strong negative selection: Topics by Science.gov

Sample records for strong negative selection

Negative selection in tumor genome evolution acts on essential cellular functions and the immunopeptidome.

PubMed

Zapata, Luis; Pich, Oriol; Serrano, Luis; Kondrashov, Fyodor A; Ossowski, Stephan; Schaefer, Martin H

2018-05-31

Natural selection shapes cancer genomes. Previous studies used signatures of positive selection to identify genes driving malignant transformation. However, the contribution of negative selection against somatic mutations that affect essential tumor functions or specific domains remains a controversial topic. Here, we analyze 7546 individual exomes from 26 tumor types from TCGA data to explore the portion of the cancer exome under negative selection. Although we find most of the genes neutrally evolving in a pan-cancer framework, we identify essential cancer genes and immune-exposed protein regions under significant negative selection. Moreover, our simulations suggest that the amount of negative selection is underestimated. We therefore choose an empirical approach to identify genes, functions, and protein regions under negative selection. We find that expression and mutation status of negatively selected genes is indicative of patient survival. Processes that are most strongly conserved are those that play fundamental cellular roles such as protein synthesis, glucose metabolism, and molecular transport. Intriguingly, we observe strong signals of selection in the immunopeptidome and proteins controlling peptide exposition, highlighting the importance of immune surveillance evasion. Additionally, tumor type-specific immune activity correlates with the strength of negative selection on human epitopes. In summary, our results show that negative selection is a hallmark of cell essentiality and immune response in cancer. The functional domains identified could be exploited therapeutically, ultimately allowing for the development of novel cancer treatments.
Investigating a memory-based account of negative priming: support for selection-feature mismatch.

PubMed

MacDonald, P A; Joordens, S

2000-08-01

Using typical and modified negative priming tasks, the selection-feature mismatch account of negative priming was tested. In the modified task, participants performed selections on the basis of a semantic feature (e.g., referent size). This procedure has been shown to enhance negative priming (P. A. MacDonald, S. Joordens, & K. N. Seergobin, 1999). Across 3 experiments, negative priming occurred only when the repeated item mismatched in terms of the feature used as the basis for selections. When the repeated item was congruent on the selection feature across the prime and probe displays, positive priming arose. This pattern of results appeared in both the ignored- and the attended-repetition conditions. Negative priming does not result from previously ignoring an item. These findings strongly support the selection-feature mismatch account of negative priming and refute both the distractor inhibition and the episodic-retrieval explanations.
Counterintuitive effects of negative social feedback on attention.

PubMed

Anderson, Brian A

2017-04-01

Which stimuli we pay attention to is strongly influenced by learning. Stimuli previously associated with reward outcomes, such as money and food, and stimuli previously associated with aversive outcomes, such as monetary loss and electric shock, automatically capture attention. Social reward (happy expressions) can bias attention towards associated stimuli, but the role of negative social feedback in biasing attentional selection remains unexplored. On the one hand, negative social feedback often serves to discourage particular behaviours. If attentional selection can be curbed much like any other behavioural preference, we might expect stimuli associated with negative social feedback to be more readily ignored. On the other hand, if negative social feedback influences attention in the same way that other aversive outcomes do, such feedback might ironically bias attention towards the stimuli it is intended to discourage selection of. In the present study, participants first completed a training phase in which colour targets were associated with negative social feedback. Then, in a subsequent test phase, these same colour stimuli served as task-irrelevant distractors during a visual search task. The results strongly support the latter interpretation in that stimuli previously associated with negative social feedback impaired search performance.
A cognitive-perceptual model of symptom perception in males and females: the roles of negative affect, selective attention, health anxiety and psychological job demands.

PubMed

Goodwin, Laura; Fairclough, Stephen H; Poole, Helen M

2013-06-01

Kolk et al.'s model of symptom perception underlines the effects of trait negative affect, selective attention and external stressors. The current study tested this model in 263 males and 498 females from an occupational sample. Trait negative affect was associated with symptom reporting in females only, and selective attention and psychological job demands were associated with symptom reporting in both genders. Health anxiety was associated with symptom reporting in males only. Future studies might consider the inclusion of selective attention, which was more strongly associated with symptom reporting than negative affect. Psychological job demands appear to influence symptom reporting in both males and females.
Choices between positive and negative reinforcement during treatment for escape-maintained behavior.

PubMed

DeLeon, I G; Neidert, P L; Anders, B M; Rodriguez-Catter, V

2001-01-01

Positive reinforcement was more effective than negative reinforcement in promoting compliance and reducing escape-maintained problem behavior for a child with autism. Escape extinction was then added while the child was given a choice between positive or negative reinforcement for compliance and the reinforcement schedule was thinned. When the reinforcement requirement reached 10 consecutive tasks, the treatment effects became inconsistent and reinforcer selection shifted from a strong preference for positive reinforcement to an unstable selection pattern.
The choices we make: An examination of situation selection in younger and older adults

PubMed Central

Rovenpor, Daniel R.; Skogsberg, Nikolaus J.; Isaacowitz, Derek M.

2013-01-01

The current study examined the effects of age and control beliefs on the use of situation selection. Younger and older adults spent 15 minutes in a room containing multiple affective streams that varied in emotional valence, and were given free choice to engage with whatever they wanted. No significant main effect of age emerged on the number of choices of, or time spent with, material of each valence. However, age and beliefs interacted such that older adults with strong emotion regulation self-efficacy and general control beliefs chose fewer negative stimuli, whereas younger adults with strong beliefs chose more negative stimuli. Results are discussed from aging and individual differences perspectives. PMID:23088197
Weak Negative and Positive Selection and the Drift Load at Splice Sites

PubMed Central

Denisov, Stepan V.; Bazykin, Georgii A.; Sutormin, Roman; Favorov, Alexander V.; Mironov, Andrey A.; Gelfand, Mikhail S.; Kondrashov, Alexey S.

2014-01-01

Splice sites (SSs) are short sequences that are crucial for proper mRNA splicing in eukaryotic cells, and therefore can be expected to be shaped by strong selection. Nevertheless, in mammals and in other intron-rich organisms, many of the SSs often involve nonconsensus (Nc), rather than consensus (Cn), nucleotides, and beyond the two critical nucleotides, the SSs are not perfectly conserved between species. Here, we compare the SS sequences between primates, and between Drosophila fruit flies, to reveal the pattern of selection acting at SSs. Cn-to-Nc substitutions are less frequent, and Nc-to-Cn substitutions are more frequent, than neutrally expected, indicating, respectively, negative and positive selection. This selection is relatively weak (1 < |4Nes| < 4), and has a similar efficiency in primates and in Drosophila. Within some nucleotide positions, the positive selection in favor of Nc-to-Cn substitutions is weaker than the negative selection maintaining already established Cn nucleotides; this difference is due to site-specific negative selection favoring current Nc nucleotides. In general, however, the strength of negative selection protecting the Cn alleles is similar in magnitude to the strength of positive selection favoring replacement of Nc alleles, as expected under the simple nearly neutral turnover. In summary, although a fraction of the Nc nucleotides within SSs is maintained by selection, the abundance of deleterious nucleotides in this class suggests a substantial genome-wide drift load. PMID:24966225
Ratings for emotion film clips.

PubMed

Gabert-Quillen, Crystal A; Bartolini, Ellen E; Abravanel, Benjamin T; Sanislow, Charles A

2015-09-01

Film clips are widely utilized to elicit emotion in a variety of research studies. Normative ratings for scenes selected for these purposes support the idea that selected clips correspond to the intended target emotion, but studies reporting normative ratings are limited. Using an ethnically diverse sample of college undergraduates, selected clips were rated for intensity, discreteness, valence, and arousal. Variables hypothesized to affect the perception of stimuli (i.e., gender, race-ethnicity, and familiarity) were also examined. Our analyses generally indicated that males reacted strongly to positively valenced film clips, whereas females reacted more strongly to negatively valenced film clips. Caucasian participants tended to react more strongly to the film clips, and we found some variation by race-ethnicity across target emotions. Finally, familiarity with the films tended to produce higher ratings for positively valenced film clips, and lower ratings for negatively valenced film clips. These findings provide normative ratings for a useful set of film clips for the study of emotion, and they underscore factors to be considered in research that utilizes scenes from film for emotion elicitation.
Recurrent Reverse Evolution Maintains Polymorphism after Strong Bottlenecks in Commensal Gut Bacteria

PubMed Central

Ramiro, Ricardo S.; Barroso-Batista, João; Güleresi, Daniela; Lourenço, Marta; Gordo, Isabel

2017-01-01

Abstract The evolution of new strains within the gut ecosystem is poorly understood. We used a natural but controlled system to follow the emergence of intraspecies diversity of commensal Escherichia coli, during three rounds of adaptation to the mouse gut (∼1,300 generations). We previously showed that, in the first round, a strongly beneficial phenotype (loss-of-function for galactitol consumption; gat-negative) spread to >90% frequency in all colonized mice. Here, we show that this loss-of-function is repeatedly reversed when a gat-negative clone colonizes new mice. The regain of function occurs via compensatory mutation and reversion, the latter leaving no trace of past adaptation. We further show that loss-of-function adaptive mutants reevolve, after colonization with an evolved gat-positive clone. Thus, even under strong bottlenecks a regime of strong-mutation-strong-selection dominates adaptation. Coupling experiments and modeling, we establish that reverse evolution recurrently generates two coexisting phenotypes within the microbiota that can or not consume galactitol (gat-positive and gat-negative, respectively). Although the abundance of the dominant strain, the gat-negative, depends on the microbiota composition, gat-positive abundance is independent of the microbiota composition and can be precisely manipulated by supplementing the diet with galactitol. These results show that a specific diet is able to change the abundance of specific strains. Importantly, we find polymorphism for these phenotypes in indigenous Enterobacteria of mice and man. Our results demonstrate that natural selection can greatly overwhelm genetic drift at structuring the strain diversity of gut commensals and that competition for limiting resources may be a key mechanism for maintaining polymorphism in the gut. PMID:28961745
Maintenance of Genetic Variability under Strong Stabilizing Selection: A Two-Locus Model

PubMed Central

Gavrilets, S.; Hastings, A.

1993-01-01

We study a two locus model with additive contributions to the phenotype to explore the relationship between stabilizing selection and recombination. We show that if the double heterozygote has the optimum phenotype and the contributions of the loci to the trait are different, then any symmetric stabilizing selection fitness function can maintain genetic variability provided selection is sufficiently strong relative to linkage. We present results of a detailed analysis of the quadratic fitness function which show that selection need not be extremely strong relative to recombination for the polymorphic equilibria to be stable. At these polymorphic equilibria the mean value of the trait, in general, is not equal to the optimum phenotype, there exists a large level of negative linkage disequilibrium which ``hides'' additive genetic variance, and different equilibria can be stable simultaneously. We analyze dependence of different characteristics of these equilibria on the location of optimum phenotype, on the difference in allelic effect, and on the strength of selection relative to recombination. Our overall result that stabilizing selection does not necessarily eliminate genetic variability is compatible with some experimental results where the lines subject to strong stabilizing selection did not have significant reductions in genetic variability. PMID:8514145
Selection signatures in four lignin genes from switchgrass populations divergently selected for in vitro dry matter digestibility

USDA-ARS?s Scientific Manuscript database

Switchgrass is undergoing development as a dedicated cellulosic bioenergy crop. Fermentation of lignocellulosic biomass to ethanol in a bioenergy system, or to volatile fatty acids in a livestock production system, is strongly and negatively influenced by lignification of cell walls. This study dete...
Negative mobility of a Brownian particle: Strong damping regime

NASA Astrophysics Data System (ADS)

Słapik, A.; Łuczka, J.; Spiechowicz, J.

2018-02-01

We study impact of inertia on directed transport of a Brownian particle under non-equilibrium conditions: the particle moves in a one-dimensional periodic and symmetric potential, is driven by both an unbiased time-periodic force and a constant force, and is coupled to a thermostat of temperature T. Within selected parameter regimes this system exhibits negative mobility, which means that the particle moves in the direction opposite to the direction of the constant force. It is known that in such a setup the inertial term is essential for the emergence of negative mobility and it cannot be detected in the limiting case of overdamped dynamics. We analyse inertial effects and show that negative mobility can be observed even in the strong damping regime. We determine the optimal dimensionless mass for the presence of negative mobility and reveal three mechanisms standing behind this anomaly: deterministic chaotic, thermal noise induced and deterministic non-chaotic. The last origin has never been reported. It may provide guidance to the possibility of observation of negative mobility for strongly damped dynamics which is of fundamental importance from the point of view of biological systems, all of which in situ operate in fluctuating environments.
The interplay between the Aharonov-Bohm interference and parity selective tunneling in graphene nanoribbon rings.

PubMed

Nguyen, V Hung; Niquet, Y-M; Dollfus, P

2014-05-21

We report on a numerical study of the Aharonov-Bohm (AB) effect and parity selective tunneling in pn junctions based on rectangular graphene rings where the contacts and ring arms are all made of zigzag nanoribbons. We find that when applying a magnetic field to the ring, the AB interference can reverse the parity symmetry of incoming waves and hence can strongly modulate the parity selective transmission through the system. Therefore, the transmission between two states of different parity exhibits the AB oscillations with a π-phase shift, compared to the case of states of the same parity. On this basis, it is shown that interesting effects, such as giant (both positive and negative) magnetoresistance and strong negative differential conductance, can be achieved in this structure. Our study thus presents a new property of the AB interference in graphene nanorings, which could be helpful for further understanding the transport properties of graphene mesoscopic systems.
Usefulness of a break-apart FISH assay in the diagnosis of Xp11.2 translocation renal cell carcinoma.

PubMed

Kim, Soo Hee; Choi, Yoomi; Jeong, Hae Yeon; Lee, Kyoungbun; Chae, Ji Youn; Moon, Kyung Chul

2011-09-01

Xp11.2 translocation renal cell carcinoma (RCC) is a rare subtype of RCC predominantly reported in young patients. It results from gene fusions between the transcription factor E3 (TFE3) gene, which is located on chromosome Xp11.2, and various fusion partners. Recently, a dual color, break-apart fluorescence in situ hybridization (FISH) assay to detect Xp11.2 translocation was reported. We performed this study to evaluate the usefulness of the FISH assay in the diagnosis of Xp11.2 translocation RCC using a commercially available TFE3 break-apart probe. We immunohistochemically analyzed TFE3 nuclear expression in 809 cases of RCCs using 14 tissue microarray blocks and selected nine cases those showed moderate to strong positive nuclear immunoreactivity for TFE3. The extent of TFE3 nuclear expression was variable. The TFE3 FISH assay was performed in these 9 selected cases and 44 negative control cases. Only four out of nine selected cases showed the TFE3 break-apart signal. TFE3 FISH-positive cases mainly showed diffuse and strong TFE3 immunopositivity, but one case revealed focal and moderate TFE3 staining. On the contrary, TFE3 FISH-negative cases mainly revealed focal and moderate TFE3 immunoreactivity, however, one FISH-negative case revealed diffuse and strong TFE3 nuclear immunopositivity. All negative control cases revealed normal TFE3 FISH results. Our results reveal that TFE3 immunohistochemistry can show false-positive results, and that the TFE3 break-apart FISH assay is a useful complementary method for confirming the diagnosis of Xp11.2 translocation RCC.
Molecular evolution of pentatricopeptide repeat genes reveals truncation in species lacking an editing target and structural domains under distinct selective pressures.

PubMed

Hayes, Michael L; Giang, Karolyn; Mulligan, R Michael

2012-05-14

Pentatricopeptide repeat (PPR) proteins are required for numerous RNA processing events in plant organelles including C-to-U editing, splicing, stabilization, and cleavage. Fifteen PPR proteins are known to be required for RNA editing at 21 sites in Arabidopsis chloroplasts, and belong to the PLS class of PPR proteins. In this study, we investigate the co-evolution of four PPR genes (CRR4, CRR21, CLB19, and OTP82) and their six editing targets in Brassicaceae species. PPR genes are composed of approximately 10 to 20 tandem repeats and each repeat has two α-helical regions, helix A and helix B, that are separated by short coil regions. Each repeat and structural feature was examined to determine the selective pressures on these regions. All of the PPR genes examined are under strong negative selection. Multiple independent losses of editing site targets are observed for both CRR21 and OTP82. In several species lacking the known editing target for CRR21, PPR genes are truncated near the 17th PPR repeat. The coding sequences of the truncated CRR21 genes are maintained under strong negative selection; however, the 3' UTR sequences beyond the truncation site have substantially diverged. Phylogenetic analyses of four PPR genes show that sequences corresponding to helix A are high compared to helix B sequences. Differential evolutionary selection of helix A versus helix B is observed in both plant and mammalian PPR genes. PPR genes and their cognate editing sites are mutually constrained in evolution. Editing sites are frequently lost by replacement of an edited C with a genomic T. After the loss of an editing site, the PPR genes are observed with three outcomes: first, few changes are detected in some cases; second, the PPR gene is present as a pseudogene; and third, the PPR gene is present but truncated in the C-terminal region. The retention of truncated forms of CRR21 that are maintained under strong negative selection even in the absence of an editing site target suggests that unrecognized function(s) might exist for this PPR protein. PPR gene sequences that encode helix A are under strong selection, and could be involved in RNA substrate recognition.
Evolution of genetic architecture under directional selection.

PubMed

Hansen, Thomas F; Alvarez-Castro, José M; Carter, Ashley J R; Hermisson, Joachim; Wagner, Günter P

2006-08-01

We investigate the multilinear epistatic model under mutation-limited directional selection. We confirm previous results that only directional epistasis, in which genes on average reinforce or diminish each other's effects, contribute to the initial evolution of mutational effects. Thus, either canalization or decanalization can occur under directional selection, depending on whether positive or negative epistasis is prevalent. We then focus on the evolution of the epistatic coefficients themselves. In the absence of higher-order epistasis, positive pairwise epistasis will tend to weaken relative to additive effects, while negative pairwise epistasis will tend to become strengthened. Positive third-order epistasis will counteract these effects, while negative third-order epistasis will reinforce them. More generally, gene interactions of all orders have an inherent tendency for negative changes under directional selection, which can only be modified by higher-order directional epistasis. We identify three types of nonadditive quasi-equilibrium architectures that, although not strictly stable, can be maintained for an extended time: (1) nondirectional epistatic architectures; (2) canalized architectures with strong epistasis; and (3) near-additive architectures in which additive effects keep increasing relative to epistasis.
Extrinsic Cation Selectivity of 2D Membranes

PubMed Central

2017-01-01

From a systematic study of the concentration driven diffusion of positive and negative ions across porous 2D membranes of graphene and hexagonal boron nitride (h-BN), we prove their cation selectivity. Using the current–voltage characteristics of graphene and h-BN monolayers separating reservoirs of different salt concentrations, we calculate the reversal potential as a measure of selectivity. We tune the Debye screening length by exchanging the salt concentrations and demonstrate that negative surface charge gives rise to cation selectivity. Surprisingly, h-BN and graphene membranes show similar characteristics, strongly suggesting a common origin of selectivity in aqueous solvents. For the first time, we demonstrate that the cation flux can be increased by using ozone to create additional pores in graphene while maintaining excellent selectivity. We discuss opportunities to exploit our scalable method to use 2D membranes for applications including osmotic power conversion. PMID:28157333
Fitness costs and benefits of novel herbicide tolerance in a noxious weed

PubMed Central

Baucom, Regina S.; Mauricio, Rodney

2004-01-01

Glyphosate, the active ingredient in the herbicide RoundUp, has increased dramatically in use over the past decade and constitutes a potent anthropogenic source of selection. In the southeastern United States, weedy morning glories have begun to develop tolerance to glyphosate, representing a unique opportunity to examine the evolutionary genetics of a novel trait. We found genetic variation for tolerance, indicating the potential for the population to respond to selection by glyphosate. However, the following significant evolutionary constraint exists: in the absence of glyphosate, tolerant genotypes produced fewer seeds than susceptible genotypes. The combination of strong positive directional selection in the presence of glyphosate and strong negative directional selection in its absence may indicate that the selective landscape of land use could drive the evolutionary trajectory of glyphosate tolerance. Understanding these evolutionary forces is imperative for devising comprehensive management strategies to help slow the rate of the evolution of tolerance. PMID:15326309
Terminal differentiation of T cells is strongly associated with CMV infection and increased in HIV-positive individuals on ART and lifestyle matched controls

PubMed Central

Booiman, Thijs; Wit, Ferdinand W.; Girigorie, Arginell F.; Maurer, Irma; De Francesco, Davide; Sabin, Caroline A.; Harskamp, Agnes M.; Prins, Maria; Franceschi, Claudio; Deeks, Steven G.; Winston, Alan; Reiss, Peter

2017-01-01

HIV-1-positive individuals on successful antiretroviral therapy (ART) are reported to have higher rates of age-associated non-communicable comorbidities (AANCCs). HIV-associated immune dysfunction has been suggested to contribute to increased AANCC risk. Here we performed a cross-sectional immune phenotype analysis of T cells in ART-treated HIV-1-positive individuals with undetectable vireamia (HIV-positives) and HIV-1-negative individuals (HIV-negatives) over 45 years of age. In addition, two control groups were studied: HIV negative adults selected based on lifestyle and demographic factors (Co-morBidity in Relation to AIDS, or COBRA) and unselected age-matched donors from a blood bank. Despite long-term ART (median of 12.2 years), HIV-infected adults had lower CD4+ T-cell counts and higher CD8+ T-cell counts compared to well-matched HIV-negative COBRA participants. The proportion of CD38+HLA-DR+ and PD-1+ CD4+ T-cells was higher in HIV-positive cohort compared to the two HIV-negative cohorts. The proportion CD57+ and CD27−CD28− cells of both CD4+ and CD8+ T-cells in HIV-positives was higher compared to unselected adults (blood bank) as reported before but this difference was not apparent in comparison with well-matched HIV-negative COBRA participants. Multiple regression analysis showed that the presence of an increased proportion of terminally differentiated T cells was strongly associated with CMV infection. Compared to appropriately selected HIV-negative controls, HIV-positive individuals on ART with long-term suppressed viraemia exhibited incomplete immune recovery and increased immune activation/exhaustion. CMV infection rather than treated HIV infection appears to have more consistent effects on measures of terminal differentiation of T cells. PMID:28806406
A Model-Based Approach for Identifying Signatures of Ancient Balancing Selection in Genetic Data

PubMed Central

DeGiorgio, Michael; Lohmueller, Kirk E.; Nielsen, Rasmus

2014-01-01

While much effort has focused on detecting positive and negative directional selection in the human genome, relatively little work has been devoted to balancing selection. This lack of attention is likely due to the paucity of sophisticated methods for identifying sites under balancing selection. Here we develop two composite likelihood ratio tests for detecting balancing selection. Using simulations, we show that these methods outperform competing methods under a variety of assumptions and demographic models. We apply the new methods to whole-genome human data, and find a number of previously-identified loci with strong evidence of balancing selection, including several HLA genes. Additionally, we find evidence for many novel candidates, the strongest of which is FANK1, an imprinted gene that suppresses apoptosis, is expressed during meiosis in males, and displays marginal signs of segregation distortion. We hypothesize that balancing selection acts on this locus to stabilize the segregation distortion and negative fitness effects of the distorter allele. Thus, our methods are able to reproduce many previously-hypothesized signals of balancing selection, as well as discover novel interesting candidates. PMID:25144706

A model-based approach for identifying signatures of ancient balancing selection in genetic data.

PubMed

DeGiorgio, Michael; Lohmueller, Kirk E; Nielsen, Rasmus

2014-08-01

While much effort has focused on detecting positive and negative directional selection in the human genome, relatively little work has been devoted to balancing selection. This lack of attention is likely due to the paucity of sophisticated methods for identifying sites under balancing selection. Here we develop two composite likelihood ratio tests for detecting balancing selection. Using simulations, we show that these methods outperform competing methods under a variety of assumptions and demographic models. We apply the new methods to whole-genome human data, and find a number of previously-identified loci with strong evidence of balancing selection, including several HLA genes. Additionally, we find evidence for many novel candidates, the strongest of which is FANK1, an imprinted gene that suppresses apoptosis, is expressed during meiosis in males, and displays marginal signs of segregation distortion. We hypothesize that balancing selection acts on this locus to stabilize the segregation distortion and negative fitness effects of the distorter allele. Thus, our methods are able to reproduce many previously-hypothesized signals of balancing selection, as well as discover novel interesting candidates.
Quantifying six decades of fishery selection for size and age at maturity in sockeye salmon

PubMed Central

Kendall, Neala W; Hard, Jeffrey J; Quinn, Thomas P

2009-01-01

Life history traits of wild animals can be strongly influenced, both phenotypically and evolutionarily, by hunting and fishing. However, few studies have quantified fishery selection over long time periods. We used 57 years of catch and escapement data to document the magnitude of and trends in gillnet selection on age and size at maturity of a commercially and biologically important sockeye salmon stock. Overall, the fishery has caught larger fish than have escaped to spawn, but selection has varied over time, becoming weaker and less consistent recently. Selection patterns were strongly affected by fish age and sex, in addition to extrinsic factors including fish abundance, mesh size regulations, and fish length variability. These results revealed a more complex and changing pattern of selective harvest than the ‘larger is more vulnerable’ model, emphasizing the need for quantified, multi-year studies before conclusions can be drawn about potential evolutionary and ecological effects of fishery selection. Furthermore, the results indicate that biologically robust escapement goals and prevention of harvest of the largest individuals may help prevent negative effects of size-selective harvest. PMID:25567896
Aerobiological Stabilities of Different Species of Gram-Negative Bacteria, Including Well-Known Biothreat Simulants, in Single-Cell Particles and Cell Clusters of Different Compositions

PubMed Central

Skogan, Gunnar

2017-01-01

ABSTRACT The ability to perform controlled experiments with bioaerosols is a fundamental enabler of many bioaerosol research disciplines. A practical alternative to using hazardous biothreat agents, e.g., for detection equipment development and testing, involves using appropriate model organisms (simulants). Several species of Gram-negative bacteria have been used or proposed as biothreat simulants. However, the appropriateness of different bacterial genera, species, and strains as simulants is still debated. Here, we report aerobiological stability characteristics of four species of Gram-negative bacteria (Pantoea agglomerans, Serratia marcescens, Escherichia coli, and Xanthomonas arboricola) in single-cell particles and cell clusters produced using four spray liquids (H2O, phosphate-buffered saline[PBS], spent culture medium[SCM], and a SCM-PBS mixture). E. coli showed higher stability in cell clusters from all spray liquids than the other species, but it showed similar or lower stability in single-cell particles. The overall stability was higher in cell clusters than in single-cell particles. The highest overall stability was observed for bioaerosols produced using SCM-containing spray liquids. A key finding was the observation that stability differences caused by particle size or compositional changes frequently followed species-specific patterns. The results highlight how even moderate changes to one experimental parameter, e.g., bacterial species, spray liquid, or particle size, can strongly affect the aerobiological stability of Gram-negative bacteria. Taken together, the results highlight the importance of careful and informed selection of Gram-negative bacterial biothreat simulants and also the accompanying particle size and composition. The outcome of this work contributes to improved selection of simulants, spray liquids, and particle size for use in bioaerosol research. IMPORTANCE The outcome of this work contributes to improved selection of simulants, spray liquids, and particle size for use in bioaerosol research. Taken together, the results highlight the importance of careful and informed selection of Gram-negative bacterial biothreat simulants and also the accompanying particle size and composition. The results highlight how even moderate changes to one experimental parameter, e.g., bacterial species, spray liquid, or particle size, can strongly affect the aerobiological stability of Gram-negative bacteria. A key finding was the observation that stability differences caused by particle size or compositional changes frequently followed species-specific patterns. PMID:28687646
Hot topic: Bovine leukemia virus (BLV)-infected cows with low proviral load are not a source of infection for BLV-free cattle.

PubMed

Juliarena, Marcela A; Barrios, Clarisa N; Ceriani, M Carolina; Esteban, Eduardo N

2016-06-01

The bovine leukemia virus (BLV) causes leukemia or lymphoma in cattle. Although most BLV-infected animals do not develop the disease, they maintain the transmission chain of BLV at the herd level. As a feasible approach to control the virus, selection of cattle carrying the BoLA-DRB3*0902 allele has been proposed, as this allele is strongly associated with a BLV infection profile or the low proviral load (LPL) phenotype. To test whether these cattle affect the BLV transmission chain under natural conditions, selected BLV-infected LPL-BoLA-DRB3*0902 heterozygous cows were incorporated into a BLV-negative dairy herd. An average ratio of 5.4 (range 4.17-6.37) BLV-negative cows per BLV-infected cow was maintained during the 20mo of the experiment, and no BLV-negative cattle became infected. The BLV incidence rate in this herd was thus zero, whereas BLV incidence rates in different local herds varied from 0.06 to 0.17 cases per 100 cattle-days. This finding strongly suggests that LPL-BoLA-DRB3*0902 cattle disrupted the BLV-transmission chain in the study period. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Host-Plant Selectivity of Rhizobacteria in a Crop/Weed Model System

PubMed Central

Zeller, Simon L.; Brandl, Helmut; Schmid, Bernhard

2007-01-01

Belowground microorganisms are known to influence plants' performance by altering the soil environment. Plant pathogens such as cyanide-producing strains of the rhizobacterium Pseudomonas may show strong host-plant selectivity. We analyzed interactions between different host plants and Pseudomonas strains and tested if these can be linked to the cyanide sensitivity of host plants, the cyanide production of bacterial strains or the plant identity from which strains had been isolated. Eight strains (four cyanide producing) were isolated from roots of four weed species and then re-inoculated on the four weed and two additional crop species. Bacterial strain composition varied strongly among the four weed species. Although all six plant species showed different reductions in root growth when cyanide was artificially applied to seedlings, they were generally not negatively affected by inoculation with cyanide-producing bacterial strains. We found a highly significant plant species x bacterial strain interaction. Partitioning this interaction into contrasts showed that it was entirely due to a strongly negative effect of a bacterial strain (Pseudomonas kilonensis/brassicacearum, isolated from Galium mollugo) on Echinochloa crus-galli. This exotic weed may not have become adapted to the bacterial strain isolated from a native weed. Our findings suggest that host-specific rhizobacteria hold some promise as biological weed-control agents. PMID:17786217
Optimization of microelectrophoresis to select highly negatively charged sperm.

PubMed

Simon, Luke; Murphy, Kristin; Aston, Kenneth I; Emery, Benjamin R; Hotaling, James M; Carrell, Douglas T

2016-06-01

The sperm membrane undergoes extensive surface remodeling as it matures in the epididymis. During this process, the sperm is encapsulated in an extensive glycocalyx layer, which provides the membrane with its characteristic negative electrostatic charge. In this study, we develop a method of microelectrophoresis and standardize the protocol to isolate sperm with high negative membrane charge. Under an electric field, the percentage of positively charged sperm (PCS), negatively charged sperm (NCS), and neutrally charged sperm was determined for each ejaculate prior to and following density gradient centrifugation (DGC), and evaluated for sperm DNA damage, and histone retention. Subsequently, PCS, NCS, and neutrally charged sperm were selected using an ICSI needle and directly analyzed for DNA damage. When raw semen was analyzed using microelectrophoresis, 94 % were NCS. In contrast, DGC completely or partially stripped the negative membrane charge from sperm resulting PCS and neutrally charged sperm, while the charged sperm populations are increased with an increase in electrophoretic current. Following DGC, high sperm DNA damage and abnormal histone retention were inversely correlated with percentage NCS and directly correlated with percentage PCS. NCS exhibited significantly lower DNA damage when compared with control (P < 0.05) and PCS (P < 0.05). When the charged sperm population was corrected for neutrally charged sperm, sperm DNA damage was strongly associated with NCS at a lower electrophoretic current. The results suggest that selection of NCS at lower current may be an important biomarker to select healthy sperm for assisted reproductive treatment.
Young Adults' Food Selection Patterns: Relations with Binge Eating and Restraint

ERIC Educational Resources Information Center

Lydecker, Janet A.; Palmberg, Allison A.; Hill, Katherine Vatalaro; Mazzeo, Suzanne E.

2015-01-01

Binge eating is increasingly prevalent in college students (White, Reynolds-Malear, & Cordero, 2011). Binge episodes involve eating an objectively large quantity of food in a discrete amount of time and a perceived lost control over eating (American Psychiatric Association [APA], 2013). Strong negative affect commonly precedes and follows each…
Item Selection, Evaluation, and Simple Structure in Personality Data

PubMed Central

Pettersson, Erik; Turkheimer, Eric

2010-01-01

We report an investigation of the genesis and interpretation of simple structure in personality data using two very different self-reported data sets. The first consists of a set of relatively unselected lexical descriptors, whereas the second is based on responses to a carefully constructed instrument. In both data sets, we explore the degree of simple structure by comparing factor solutions to solutions from simulated data constructed to have either strong or weak simple structure. The analysis demonstrates that there is little evidence of simple structure in the unselected items, and a moderate degree among the selected items. In both instruments, however, much of the simple structure that could be observed originated in a strong dimension of positive vs. negative evaluation. PMID:20694168
Vibronic coupling and selectivity of vibrational excitation in the negative ion resonances of ozone

NASA Astrophysics Data System (ADS)

Allan, Michael; Popovic̀, Duška B.

1997-04-01

A recent experimental paper reported two shape resonances in electron impact on ozone, A 1 and B 2, both causing vibrational excitation with a distinct pattern of selectivity. The present Letter attempts to rationalize this selectivity using approximate potential curves, calculated for the A 1 and B 2 resonances by adding the SCF energy of neutral ozone to electron attachment energies calculated from ab initio virtual orbital energies using the Koopmans' theorem and an empirical scaling relation. The slopes of the curves explain the efficient excitation of the symmetric stretch by both resonances and the lack of the bending excitation by the B 2 resonance. The A 1 and B 2 resonances are strongly coupled by the b 2 antisymmetric stretch vibration, causing a double minimum on the lower surface. Nonadiabatic effects caused by the strong vibronic coupling explain the observed excitation of the antisymmetric stretch vibration.
Catch a tiger snake by its tail: Differential toxicity, co-factor dependence and antivenom efficacy in a procoagulant clade of Australian venomous snakes.

PubMed

Lister, Callum; Arbuckle, Kevin; Jackson, Timothy N W; Debono, Jordan; Zdenek, Christina N; Dashevsky, Daniel; Dunstan, Nathan; Allen, Luke; Hay, Chris; Bush, Brian; Gillett, Amber; Fry, Bryan G

2017-11-01

A paradigm of venom research is adaptive evolution of toxins as part of a predator-prey chemical arms race. This study examined differential co-factor dependence, variations relative to dietary preference, and the impact upon relative neutralisation by antivenom of the procoagulant toxins in the venoms of a clade of Australian snakes. All genera were characterised by venoms rich in factor Xa which act upon endogenous prothrombin. Examination of toxin sequences revealed an extraordinary level of conservation, which indicates that adaptive evolution is not a feature of this toxin type. Consistent with this, the venoms did not display differences on the plasma of different taxa. Examination of the prothrombin target revealed endogenous blood proteins are under extreme negative selection pressure for diversification, this in turn puts a strong negative selection pressure upon the toxins as sequence diversification could result in a drift away from the target. Thus this study reveals that adaptive evolution is not a consistent feature in toxin evolution in cases where the target is under negative selection pressure for diversification. Consistent with this high level of toxin conservation, the antivenom showed extremely high-levels of cross-reactivity. There was however a strong statistical correlation between relative degree of phospholipid-dependence and clotting time, with the least dependent venoms producing faster clotting times than the other venoms even in the presence of phospholipid. The results of this study are not only of interest to evolutionary and ecological disciplines, but also have implications for clinical toxinology. Copyright © 2017 Elsevier Inc. All rights reserved.
Behavior and nutritional condition buffer a large-bodied endotherm against direct and indirect effects of climate

Treesearch

Ryan A. Long; R. Terry Bowyer; Warren P. Porter; Paul Mathewson; Kevin L. Monteith; John G. Kie

2014-01-01

Temporal changes in net energy balance of animals strongly influence fitness; consequently, natural selection should favor behaviors that increase net energy balance by buffering individuals against negative effects of environmental variation. The relative importance of behavioral responses to climate-induced variation in costs vs. supplies of energy, however, is...
Rejected by Peers--Attracted to Antisocial Media Content: Rejection-Based Anger Impairs Moral Judgment among Adolescents

ERIC Educational Resources Information Center

Plaisier, Xanthe S.; Konijn, Elly A.

2013-01-01

Adolescence is an important developmental stage during which both peers and the media have a strong influence. Both peer rejection and the use of morally adverse media are associated with negative developmental outcomes. This study examines processes by which peer rejection might drive adolescents to select antisocial media content by tying…
Can organized leisure-time activities buffer the negative outcomes of unstructured activities for adolescents' health?

PubMed

Badura, Petr; Madarasova Geckova, Andrea; Sigmundova, Dagmar; Sigmund, Erik; van Dijk, Jitse P; Reijneveld, Sijmen A

2018-06-02

We aimed to assess the associations of involvement in selected unstructured activities (UA) with health-risk behaviours and academic achievement and the degree to which the participation in organized leisure-time activities (OLTA) changes these associations. Using a sample of 6935 Czech adolescents aged 13 and 15 years, we investigated adolescents' weekly involvement in hanging out, visiting shopping malls for fun and meeting friends after 8 p.m., OLTA and engagement in three health-risk behaviours and academic achievement. Weekly involvement in the selected UA was associated with higher odds for regular smoking, being drunk, having early sexual intercourse and low academic achievement. Concurrent participation in OLTA did not buffer these negative outcomes, except for sexual experience. However, those highly engaged only in UA were more likely to participate in the health-risk behaviours and report worse academic achievement than those participating in any OLTA concurrently. The selected UA are strongly associated with an increased occurrence of adolescents' health-risk behaviours and low academic achievement. Concurrent participation in OLTA does not buffer these negative outcomes significantly, but adolescents engaged only in UA consistently report the least favourable outcomes.
Genetic conflict between sexual signalling and juvenile survival in the three-spined stickleback.

PubMed

Kim, Sin-Yeon; Velando, Alberto

2016-02-29

Secondary sexual traits and mating preferences may evolve in part because the offspring of attractive males inherit attractiveness and other genetically correlated traits such as fecundity and viability. A problem regarding these indirect genetic mechanisms is how sufficient genetic variation in the traits subject to sexual selection is maintained within a population. Here we explored the additive genetic correlations between carotenoid-based male ornament colouration, female fecundity and juvenile survival rate in the three-spined stickleback (Gasterosteus aculeatus) to test the possibility that attractiveness genes reduce important fitness components in the bearers not expressing the sexual trait. Male sexual attractiveness (i.e., red nuptial colouration) as well as female fecundity and juvenile viability showed heritable variations in the three-spined stickleback. Thus, females can gain indirect benefits by mating with an attractive male. There was a strong positive genetic correlation between female fecundity and juvenile viability. However, red sexual signal of male sticklebacks was negatively genetically correlated with juvenile survival, suggesting genetic conflict between attractiveness and viability. There was no significant correlation between attractiveness of brothers and fecundity of sisters, suggesting no intra-locus sexual conflict. The negative effects of mating with a colourful male on offspring viability may contribute to maintaining the heritable variation under strong directional sexual selection. The strength of indirect sexual selection may be weaker than previously thought due to the hidden genetic conflicts.
Spruce Budworm (Choristoneura fumiferana) Performance in Relation to Foliar Chemistry of its Host Plants

Treesearch

William John. Mattson

1983-01-01

Spruce budworm growth was best on balsam fir, poorest on lowland black spruce, and intermediate on upland white and black spruce. Growth was consistently, positively linked to foliar N and negatively linked to Fe, K, and select terpenes. Survival rates were not strongly, nor consistently linked to any of the measured foliar chemical traits.
Evoked and event-related potentials in disorders of consciousness: A quantitative review.

PubMed

Kotchoubey, Boris

2017-09-01

Sixty-one publications about evoked and event-related potentials (EP and ERP, respectively) in patients with severe Disorders of Consciousness (DoC) were found and analyzed from a quantitative point of view. Most studies are strongly underpowered, resulting in very broad confidence intervals (CI). Results of such studies cannot be correctly interpreted, because, for example, CI>1 (in terms of Cohen's d) indicate that the real effect may be very strong, very weak, or even opposite to the reported effect. Furthermore, strong negative correlations were obtained between sample size and effect size, indicating a possible publication bias. These correlations characterized not only the total data set, but also each thematically selected subset. The minimal criteria of a strong study to EP/ERP in DoC are proposed: at least 25 patients in each patient group; as reliable diagnosis as possible; the complete report of all methodological details and all details of results (including negative results); and the use of appropriate methods of data analysis. Only three of the detected 60 studies (5%) satisfy these criteria. The limitations of the current approach are also discussed. Copyright © 2017 Elsevier Inc. All rights reserved.
Hemispheric processing of predictive inferences during reading: The influence of negatively emotional valenced stimuli.

PubMed

Virtue, Sandra; Schutzenhofer, Michael; Tomkins, Blaine

2017-07-01

Although a left hemisphere advantage is usually evident during language processing, the right hemisphere is highly involved during the processing of weakly constrained inferences. However, currently little is known about how the emotional valence of environmental stimuli influences the hemispheric processing of these inferences. In the current study, participants read texts promoting either strongly or weakly constrained predictive inferences and performed a lexical decision task to inference-related targets presented to the left visual field-right hemisphere or the right visual field-left hemisphere. While reading these texts, participants either listened to dissonant music (i.e., the music condition) or did not listen to music (i.e., the no music condition). In the no music condition, the left hemisphere showed an advantage for strongly constrained inferences compared to weakly constrained inferences, whereas the right hemisphere showed high facilitation for both strongly and weakly constrained inferences. In the music condition, both hemispheres showed greater facilitation for strongly constrained inferences than for weakly constrained inferences. These results suggest that negatively valenced stimuli (such as dissonant music) selectively influences the right hemisphere's processing of weakly constrained inferences during reading.
Two Decades of Negative Educational Selectivity of Mexican Migrants to the United States

PubMed Central

Rendall, Michael S.; Parker, Susan W.

2015-01-01

Immigration is commonly considered to be selective of more able individuals. Studies comparing the educational attainment of Mexican immigrants in the United States to that of the Mexican resident population support this characterization. Upward educational-attainment biases in both coverage and measurement, however, may be substantial in U.S. data sources. Moreover, differences in educational attainment by place size are very large within Mexico, and U.S. data sources provide no information on immigrants’ places of origin within Mexico. To address these problems, we use multiple sources of nationally-representative Mexican survey data to re-evaluate the educational selectivity of working-age Mexican migrants to the United States over the 1990s and 2000s. We document disproportionately rural and small-urban-area origins of Mexican migrants and a steep positive gradient of educational attainment by place size. We show that together these conditions induced strongly negative educational selection of Mexican migrants throughout the 1990s and 2000s. We interpret this finding as consistent with low returns to the education of unauthorized migrants and few opportunities for authorized migration. PMID:25995526
Plant selection and soil legacy enhance long-term biodiversity effects.

PubMed

Zuppinger-Dingley, Debra; Flynn, Dan F B; De Deyn, Gerlinde B; Petermann, Jana S; Schmid, Bernhard

2016-04-01

Plant-plant and plant-soil interactions can help maintain plant diversity and ecosystem functions. Changes in these interactions may underlie experimentally observed increases in biodiversity effects over time via the selection of genotypes adapted to low or high plant diversity. Little is known, however, about such community-history effects and particularly the role of plant-soil interactions in this process. Soil-legacy effects may occur if co-evolved interactions with soil communities either positively or negatively modify plant biodiversity effects. We tested how plant selection and soil legacy influence biodiversity effects on productivity, and whether such effects increase the resistance of the communities to invasion by weeds. We used two plant selection treatments: parental plants growing in monoculture or in mixture over 8 yr in a grassland biodiversity experiment in the field, which we term monoculture types and mixture types. The two soil-legacy treatments used in this study were neutral soil inoculated with live or sterilized soil inocula collected from the same plots in the biodiversity experiment. For each of the four factorial combinations, seedlings of eight species were grown in monocultures or four-species mixtures in pots in an experimental garden over 15 weeks. Soil legacy (live inoculum) strongly increased biodiversity complementarity effects for communities of mixture types, and to a significantly weaker extent for communities of monoculture types. This may be attributed to negative plant-soil feedbacks suffered by mixture types in monocultures, whereas monoculture types had positive plant-soil feedbacks, in both monocultures and mixtures. Monocultures of mixture types were most strongly invaded by weeds, presumably due to increased pathogen susceptibility, reduced biomass, and altered plant-soil interactions of mixture types. These results show that biodiversity effects in experimental grassland communities can be modified by the evolution of positive vs. negative plant-soil feedbacks of plant monoculture vs. mixture types.
Borophene as a Promising Material for Charge-Modulated Switchable CO2 Capture.

PubMed

Tan, Xin; Tahini, Hassan A; Smith, Sean C

2017-06-14

Ideal carbon dioxide (CO 2 ) capture materials for practical applications should bind CO 2 molecules neither too weakly to limit good loading kinetics nor too strongly to limit facile release. Although charge-modulated switchable CO 2 capture has been proposed to be a controllable, highly selective, and reversible CO 2 capture strategy, the development of a practical gas-adsorbent material remains a great challenge. In this study, by means of density functional theory (DFT) calculations, we have examined the possibility of conductive borophene nanosheets as promising sorbent materials for charge-modulated switchable CO 2 capture. Our results reveal that the binding strength of CO 2 molecules on negatively charged borophene can be significantly enhanced by injecting extra electrons into the adsorbent. At saturation CO 2 capture coverage, the negatively charged borophene achieves CO 2 capture capacities up to 6.73 × 10 14 cm -2 . In contrast to the other CO 2 capture methods, the CO 2 capture/release processes on negatively charged borophene are reversible with fast kinetics and can be easily controlled via switching on/off the charges carried by borophene nanosheets. Moreover, these negatively charged borophene nanosheets are highly selective for separating CO 2 from mixtures with CH 4 , H 2 , and/or N 2 . This theoretical exploration will provide helpful guidance for identifying experimentally feasible, controllable, highly selective, and high-capacity CO 2 capture materials with ideal thermodynamics and reversibility.

Antimicrobial peptides and induced membrane curvature: geometry, coordination chemistry, and molecular engineering

PubMed Central

Schmidt, Nathan W.; Wong, Gerard C. L.

2013-01-01

Short cationic, amphipathic antimicrobial peptides are multi-functional molecules that have roles in host defense as direct microbicides and modulators of the immune response. While a general mechanism of microbicidal activity involves the selective disruption and permeabilization of cell membranes, the relationships between peptide sequence and membrane activity are still under investigation. Here, we review the diverse functions that AMPs collectively have in host defense, and show that these functions can be multiplexed with a membrane mechanism of activity derived from the generation of negative Gaussian membrane curvature. As AMPs preferentially generate this curvature in model bacterial cell membranes, the selective generation of negative Gaussian curvature provides AMPs with a broad mechanism to target microbial membranes. The amino acid constraints placed on AMPs by the geometric requirement to induce negative Gaussian curvature are consistent with known AMP sequences. This ‘saddle-splay curvature selection rule’ is not strongly restrictive so AMPs have significant compositional freedom to multiplex membrane activity with other useful functions. The observation that certain proteins involved in cellular processes which require negative Gaussian curvature contain domains with similar motifs as AMPs, suggests this rule may be applicable to other curvature-generating proteins. Since our saddle-splay curvature design rule is based upon both a mechanism of activity and the existing motifs of natural AMPs, we believe it will assist the development of synthetic antimicrobials. PMID:24778573
Symptom assessment in early psychosis: the use of well-established rating scales in clinical high-risk and recent-onset populations.

PubMed

Fulford, Daniel; Pearson, Rahel; Stuart, Barbara K; Fisher, Melissa; Mathalon, Daniel H; Vinogradov, Sophia; Loewy, Rachel L

2014-12-30

Symptom assessment in early psychosis research typically relies on scales validated in chronic schizophrenia samples. Our goal was to inform investigators who are selecting symptom scales for early psychosis research. We described measure characteristics, baseline scores, and scale inter-relationships in clinical-high-risk (CHR) and recent-onset psychotic disorder (RO) samples using the Positive and Negative Syndrome Scale, Brief Psychiatric Rating Scale, Scale for the Assessment of Positive Symptoms, and Scale for the Assessment of Negative Symptoms; for the CHR group only, we included the Scale of Prodromal Symptoms. For investigators selecting symptom measures in intervention or longitudinal studies, we also examined the relationship of symptom scales with psychosocial functioning. In both samples, symptom subscales in the same domain, across measures, were moderately to highly intercorrelated. Within all measures, positive symptoms were not correlated with negative symptoms, but disorganized symptoms overlapped with both positive and negative symptoms. Functioning was significantly related to negative and disorganized, but not positive, symptoms in both samples on most measures. Findings suggest strong overlap in symptom severity ratings among the most common scales. In recent-onset samples, each has strengths and weaknesses. In CHR samples, they appear to add little information above and beyond the SOPS. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.
Fecundity of patients with schizophrenia, autism, bipolar disorder, depression, anorexia nervosa, or substance abuse vs their unaffected siblings.

PubMed

Power, Robert A; Kyaga, Simon; Uher, Rudolf; MacCabe, James H; Långström, Niklas; Landen, Mikael; McGuffin, Peter; Lewis, Cathryn M; Lichtenstein, Paul; Svensson, Anna C

2013-01-01

It is unknown how genetic variants conferring liability to psychiatric disorders survive in the population despite strong negative selection. However, this is key to understanding their etiology and designing studies to identify risk variants. To examine the reproductive fitness of patients with schizophrenia and other psychiatric disorders vs their unaffected siblings and to evaluate the level of selection on causal genetic variants. We measured the fecundity of patients with schizophrenia, autism, bipolar disorder, depression, anorexia nervosa, or substance abuse and their unaffected siblings compared with the general population. Population databases in Sweden, including the Multi-Generation Register and the Swedish Hospital Discharge Register. In total, 2.3 million individuals among the 1950 to 1970 birth cohort in Sweden. Fertility ratio (FR), reflecting the mean number of children compared with that of the general population, accounting for age, sex, family size, and affected status. Except for women with depression, affected patients had significantly fewer children (FR range for those with psychiatric disorder, 0.23-0.93; P < 10-10). This reduction was consistently greater among men than women, suggesting that male fitness was particularly sensitive. Although sisters of patients with schizophrenia and bipolar disorder had increased fecundity (FR range, 1.02-1.03; P < .01), this was too small on its own to counterbalance the reduced fitness of affected patients. Brothers of patients with schizophrenia and autism showed reduced fecundity (FR range, 0.94-0.97; P < .001). Siblings of patients with depression and substance abuse had significantly increased fecundity (FR range, 1.01-1.05; P < 10-10). In the case of depression, this more than compensated for the lower fecundity of affected individuals. Our results suggest that strong selection exists against schizophrenia, autism, and anorexia nervosa and that these variants may be maintained by new mutations or an as-yet unknown mechanism. Bipolar disorder did not seem to be under strong negative selection. Vulnerability to depression, and perhaps substance abuse, may be preserved by balancing selection, suggesting the involvement of common genetic variants in ways that depend on other genes and on environment.
A Small Aptamer with Strong and Specific Recognition of the Triphosphate of ATP

PubMed Central

Sazani, Peter L.; Larralde, Rosa

2004-01-01

We report the in vitro selection of an RNA-based ATP aptamer with the ability to discriminate between adenosine ligands based on their 5‘ phosphorylation state. Previous selection of ATP aptamers yielded molecules that do not significantly discriminate between ligands at the 5‘ position. By applying a selective pressure that demands recognition of the 5‘ triphosphate, we obtained an aptamer that binds to ATP with a Kd of approximately 5 μM, and to AMP with a Kd of approximately 5.5 mM, a difference of 1100-fold. This aptamer demonstrates the ability of small RNAs to interact with negatively charged moieties. PMID:15237981
Statistical Investigations on Solar Wind Dynamic Pressure Pulses:Basic features and Their Impacts on Geosynchronous Magnetic Fields

NASA Astrophysics Data System (ADS)

Zuo, Pingbing; Feng, Xueshang

2016-07-01

Solar wind dynamic pressure pulse (DPP) structures, across which the dynamic pressure abruptly changes over timescales from a few seconds to several minutes, are often observed in the near-Earth space environment. Recently we have developed a novel procedure that is able to rapidly identify the DPPs from the plasma data stream, and simultaneously define the transition region and smartly select the upstream and downstream region for analysis. The plasma data with high time-resolution from 3DP instrument on board the WIND spacecraft are inspected with this automatic DPP-searching code, and a complete list of solar wind DPPs of historic WIND observations are built up. We perform a statistical survey on the properties of DPPs near 1 AU based on this event list. It is found that overwhelming majority of DPPs are associated with the solar wind disturbances including the CME-related flows, the corotating interaction regions, as well as the complex ejecta. The annual variations of the averaged occurrence rate of DPPs are roughly in phase with the solar activities. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears no systematic investigations on the response of GMFs to negative DPPs. Here we also study the decompression/compression effects of very strong negative/positive DPPs on GMFs under northward IMFs. In response to the decompression of strong negative DPPs, GMFs on dayside, near the dawn and dusk on nightside are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of events when GOES is located at the midnight sector, GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that on certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, being stronger at the noon sector.
Discovery of cancer drug targets by CRISPR-Cas9 screening of protein domains.

PubMed

Shi, Junwei; Wang, Eric; Milazzo, Joseph P; Wang, Zihua; Kinney, Justin B; Vakoc, Christopher R

2015-06-01

CRISPR-Cas9 genome editing technology holds great promise for discovering therapeutic targets in cancer and other diseases. Current screening strategies target CRISPR-Cas9-induced mutations to the 5' exons of candidate genes, but this approach often produces in-frame variants that retain functionality, which can obscure even strong genetic dependencies. Here we overcome this limitation by targeting CRISPR-Cas9 mutagenesis to exons encoding functional protein domains. This generates a higher proportion of null mutations and substantially increases the potency of negative selection. We also show that the magnitude of negative selection can be used to infer the functional importance of individual protein domains of interest. A screen of 192 chromatin regulatory domains in murine acute myeloid leukemia cells identifies six known drug targets and 19 additional dependencies. A broader application of this approach may allow comprehensive identification of protein domains that sustain cancer cells and are suitable for drug targeting.
Meta-structure correlation in protein space unveils different selection rules for folded and intrinsically disordered proteins.

PubMed

Naranjo, Yandi; Pons, Miquel; Konrat, Robert

2012-01-01

The number of existing protein sequences spans a very small fraction of sequence space. Natural proteins have overcome a strong negative selective pressure to avoid the formation of insoluble aggregates. Stably folded globular proteins and intrinsically disordered proteins (IDPs) use alternative solutions to the aggregation problem. While in globular proteins folding minimizes the access to aggregation prone regions, IDPs on average display large exposed contact areas. Here, we introduce the concept of average meta-structure correlation maps to analyze sequence space. Using this novel conceptual view we show that representative ensembles of folded and ID proteins show distinct characteristics and respond differently to sequence randomization. By studying the way evolutionary constraints act on IDPs to disable a negative function (aggregation) we might gain insight into the mechanisms by which function-enabling information is encoded in IDPs.
Genetic differentiation and selection against migrants in evolutionarily replicated extreme environments.

PubMed

Plath, Martin; Pfenninger, Markus; Lerp, Hannes; Riesch, Rüdiger; Eschenbrenner, Christoph; Slattery, Patrick A; Bierbach, David; Herrmann, Nina; Schulte, Matthias; Arias-Rodriguez, Lenin; Rimber Indy, Jeane; Passow, Courtney; Tobler, Michael

2013-09-01

We investigated mechanisms of reproductive isolation in livebearing fishes (genus Poecilia) inhabiting sulfidic and nonsulfidic habitats in three replicate river drainages. Although sulfide spring fish convergently evolved divergent phenotypes, it was unclear if mechanisms of reproductive isolation also evolved convergently. Using microsatellites, we found strongly reduced gene flow between adjacent populations from different habitat types, suggesting that local adaptation to sulfidic habitats repeatedly caused the emergence of reproductive isolation. Reciprocal translocation experiments indicate strong selection against immigrants into sulfidic waters, but also variation among drainages in the strength of selection against immigrants into nonsulfidic waters. Mate choice experiments revealed the evolution of assortative mating preferences in females from nonsulfidic but not from sulfidic habitats. The inferred strength of sexual selection against immigrants (RI(s)) was negatively correlated with the strength of natural selection (RI(m)), a pattern that could be attributed to reinforcement, whereby natural selection strengthens behavioral isolation due to reduced hybrid fitness. Overall, reproductive isolation and genetic differentiation appear to be replicated and direct consequences of local adaptation to sulfide spring environments, but the relative contributions of different mechanisms of reproductive isolation vary across these evolutionarily independent replicates, highlighting both convergent and nonconvergent evolutionary trajectories of populations in each drainage. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.
Strong pollinator-mediated selection for increased flower brightness and contrast in a deceptive orchid.

PubMed

Sletvold, Nina; Trunschke, Judith; Smit, Mart; Verbeek, Jeffrey; Ågren, Jon

2016-03-01

Contrasting flower color patterns that putatively attract or direct pollinators toward a reward are common among angiosperms. In the deceptive orchid Anacamptis morio, the lower petal, which makes up most of the floral display, has a light central patch with dark markings. Within populations, there is pronounced variation in petal brightness, patch size, amount of dark markings, and contrast between patch and petal margin. We tested whether pollinators mediate selection on these color traits and on morphology (plant height, number of flowers, corolla size, spur length), and whether selection is consistent with facilitated or negative frequency-dependent pollination. Pollinators mediated strong selection for increased petal brightness (Δβpoll = 0.42) and contrast (Δβpoll = 0.51). Pollinators also tended to mediate stabilizing selection on brightness (Δγpoll = -0.27, n.s.) favoring the most common phenotype in the population. Selection for reduced petal brightness among hand-pollinated plants indicated a fitness cost associated with brightness. The results demonstrate that flower color traits influence pollination success and seed production in A. morio, indicating that they affect attractiveness to pollinators, efficiency of pollen transfer, or both. The documented selection is consistent with facilitated pollination and selection for color convergence toward cooccurring rewarding species. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.
Through Sex, Nature Is Telling Us Something Important.

PubMed

Kondrashov, Alexey S

2018-05-01

Theoretically, a variety of mechanisms can make amphimixis advantageous due to reshuffling of offspring genotypes. Recently, it has been shown experimentally that some of these mechanisms can indeed work in artificial populations. However, we still do not know which of them, if any, are relevant in nature, and the available indirect estimates seem to suggest that neither negative nor positive selection in natural populations is strong enough to provide evolutionary protection for obligate amphimixis. Thus, progress in understanding the evolution of amphimixis will depend on direct measurements of the strength of natural selection. Copyright © 2018 Elsevier Ltd. All rights reserved.
The Tooth and Skin Colour Interrelationship across the Different Ethnic Groups

PubMed Central

Haralur, Satheesh B.; Dibas, Ahmed Mohammed; Almelhi, Nabil Abdullah; Al-Qahtani, Dhafer Ali

2014-01-01

Objectives. The purpose of the study was to investigate the relation between skin and tooth colour parameters in various ethnic groups. Materials and Methods. Saudi Arabian, Indian, African, and East Asian ethnic groups of 75 each were included in the study. The tooth colour was determined by spectrophotometer in CIELAB parameters. The skin colour was measured at earlobe, forehead, and malar locations by clinical skin photography. The data was statistically analysed by one-way ANOVA and correlation tests. Results. The “L” vale for the Saudi Arabian group had a strong correlation at earlobe location (r = 0.275), while correlation was found at forehead (r = 0.271) and malar region (r = 0.261) with Indian ethnic group. A strong negative correlation was observed in African ethnic group at all three locations for “L” parameter. The redness value “a” is found to have strong negative linear correlation between the earlobe and tooth for Saudi Arabian (r = −0.240) and Indian ethnic groups (r = −0.268). The “b” showed no correlation with skin location in all groups except positive correlation in African ethnic groups. Conclusions. The strong correlation was found between the skin and tooth colour parameters; hence the skin colour can be used as a guide for artificial tooth selection in edentulous patients. PMID:25101125
The Tooth and Skin Colour Interrelationship across the Different Ethnic Groups.

PubMed

Haralur, Satheesh B; Dibas, Ahmed Mohammed; Almelhi, Nabil Abdullah; Al-Qahtani, Dhafer Ali

2014-01-01

Objectives. The purpose of the study was to investigate the relation between skin and tooth colour parameters in various ethnic groups. Materials and Methods. Saudi Arabian, Indian, African, and East Asian ethnic groups of 75 each were included in the study. The tooth colour was determined by spectrophotometer in CIELAB parameters. The skin colour was measured at earlobe, forehead, and malar locations by clinical skin photography. The data was statistically analysed by one-way ANOVA and correlation tests. Results. The "L" vale for the Saudi Arabian group had a strong correlation at earlobe location (r = 0.275), while correlation was found at forehead (r = 0.271) and malar region (r = 0.261) with Indian ethnic group. A strong negative correlation was observed in African ethnic group at all three locations for "L" parameter. The redness value "a" is found to have strong negative linear correlation between the earlobe and tooth for Saudi Arabian (r = -0.240) and Indian ethnic groups (r = -0.268). The "b" showed no correlation with skin location in all groups except positive correlation in African ethnic groups. Conclusions. The strong correlation was found between the skin and tooth colour parameters; hence the skin colour can be used as a guide for artificial tooth selection in edentulous patients.
A networked voting rule for democratic representation

NASA Astrophysics Data System (ADS)

Hernández, Alexis R.; Gracia-Lázaro, Carlos; Brigatti, Edgardo; Moreno, Yamir

2018-03-01

We introduce a general framework for exploring the problem of selecting a committee of representatives with the aim of studying a networked voting rule based on a decentralized large-scale platform, which can assure a strong accountability of the elected. The results of our simulations suggest that this algorithm-based approach is able to obtain a high representativeness for relatively small committees, performing even better than a classical voting rule based on a closed list of candidates. We show that a general relation between committee size and representatives exists in the form of an inverse square root law and that the normalized committee size approximately scales with the inverse of the community size, allowing the scalability to very large populations. These findings are not strongly influenced by the different networks used to describe the individuals' interactions, except for the presence of few individuals with very high connectivity which can have a marginal negative effect in the committee selection process.
The Impact of a Targeted Training Program on E-Mail System Processing Capabilities and Self-Perception of E-Mail Overload

ERIC Educational Resources Information Center

Einstein, Michael M.

2014-01-01

As business e-mail volumes continue to grow and employees spend increasingly larger portions of their day processing e-mail, there is strong evidence of the negative impacts of e-mail processing, especially with respect to e-mail overload. This study sought to determine whether a training program focused on select e-mail features and processing…
Synthetic Mimic of Antimicrobial Peptide with Nonmembrane-Disrupting Antibacterial Properties

PubMed Central

2008-01-01

Polyguanidinium oxanorbornene (PGON) was synthesized from norbornene monomers via ring-opening metathesis polymerization. This polymer was observed to be strongly antibacterial against Gram-negative and Gram-positive bacteria as well as nonhemolytic against human red blood cells. Time-kill studies indicated that this polymer is lethal and not just bacteriostatic. In sharp contrast to previously reported SMAMPs (synthetic mimics of antimicrobial peptides), PGON did not disrupt membranes in vesicle-dye leakage assays and microscopy experiments. The unique biological properties of PGON, in same ways similar to cell-penetrating peptides, strongly encourage the examination of other novel guanidino containing macromolecules as powerful and selective antimicrobial agents. PMID:18850741
Ultra low-loss, isotropic optical negative-index metamaterial based on hybrid metal-semiconductor nanowires

PubMed Central

Paniagua-Domínguez, R.; Abujetas, D. R.; Sánchez-Gil, J. A.

2013-01-01

Recently, many fascinating properties predicted for metamaterials (negative refraction, superlensing, electromagnetic cloaking,…) were experimentally demonstrated. Unfortunately, the best achievements have no direct translation to the optical domain, without being burdened by technological and conceptual difficulties. Of particular importance within the realm of optical negative-index metamaterials (NIM), is the issue of simultaneously achieving strong electric and magnetic responses and low associated losses. Here, hybrid metal-semiconductor nanowires are proposed as building blocks of optical NIMs. The metamaterial thus obtained, highly isotropic in the plane normal to the nanowires, presents a negative index of refraction in the near-infrared, with values of the real part well below −1, and extremely low losses (an order of magnitude better than present optical NIMs). Tunability of the system allows to select the operating range in the whole telecom spectrum. The design is proven in configurations such as prisms and slabs, directly observing negative refraction. PMID:23514968
Somatic Mutation Patterns in Hemizygous Genomic Regions Unveil Purifying Selection during Tumor Evolution

PubMed Central

Basu, Swaraj; Larsson, Erik

2016-01-01

Identification of cancer driver genes using somatic mutation patterns indicative of positive selection has become a major goal in cancer genomics. However, cancer cells additionally depend on a large number of genes involved in basic cellular processes. While such genes should in theory be subject to strong purifying (negative) selection against damaging somatic mutations, these patterns have been elusive and purifying selection remains inadequately explored in cancer. Here, we hypothesized that purifying selection should be evident in hemizygous genomic regions, where damaging mutations cannot be compensated for by healthy alleles. Using a 7,781-sample pan-cancer dataset, we first confirmed this in POLR2A, an essential gene where hemizygous deletions are known to confer elevated sensitivity to pharmacological suppression. We next used this principle to identify several genes and pathways that show patterns indicative of purifying selection to avoid deleterious mutations. These include the POLR2A interacting protein INTS10 as well as genes involved in mRNA splicing, nonsense-mediated mRNA decay and other RNA processing pathways. Many of these genes belong to large protein complexes, and strong overlaps were observed with recent functional screens for gene essentiality in human cells. Our analysis supports that purifying selection acts to preserve the remaining function of many hemizygously deleted essential genes in tumors, indicating vulnerabilities that might be exploited by future therapeutic strategies. PMID:28027311
Zooplankton interactions with toxic phytoplankton: Some implications for food web studies and algal defence strategies of feeding selectivity behaviour, toxin dilution and phytoplankton population diversity

NASA Astrophysics Data System (ADS)

Barreiro, A.; Guisande, C.; Maneiro, I.; Vergara, A. R.; Riveiro, I.; Iglesias, P.

2007-11-01

This study focuses on the interactions between toxic phytoplankton and zooplankton grazers. The experimental conditions used are an attempt to simulate situations that have, so far, received little attention. We presume the phytoplankton community to be a set of species where a population of a toxic species is intrinsically diverse by the presence of coexisting strains with different toxic properties. The other species in the community may not always be high-quality food for herbivorous zooplankton. Zooplankton populations may have developed adaptive responses to sympatric toxic phytoplankton species. Zooplankton grazers may perform a specific feeding behaviour and its consequences on fitness will depend on the species ingested, the effect of toxins, and the presence of mechanisms of toxin dilution and compensatory feeding. Our target species are a strain of the dinoflagellate Alexandrium minutum and a sympatric population of the copepod Acartia clausi. Mixed diets were used with two kinds of A. minutum cells: non-toxic and toxic. The flagellate Rhodomonas baltica and the non-toxic dinoflagellate Alexandrium tamarense were added as accompanying species. The effect of each alga was studied in separate diets. The toxic A. minutum cells were shown to have negative effects on egg production, hatching success and total reproductive output, while, in terms of its effect on fitness, the non-toxic A. minutum was the best quality food offered. R. baltica and A. tamarense were in intermediate positions. In the mixed diets, copepods showed a strong preference for toxic A. minutum cells and a weaker one for A. tamarense cells, while non-toxic A. minutum was slightly negatively selected and R. baltica strongly negatively selected. Although the level of toxins accumulated by copepods was very similar, in both the diet with only toxic A. minutum cells and in the mixed diet, the negative effects on fitness in the mixed diet could be offset by toxin dilution mechanisms. The implications of these findings are the fact that mesozooplankton may not play an important role in phytoplankton blooms development. Phytoplankton endotoxin production does not seem to be an evolutionary stable strategy as a defence against some herbivores.
Activation-induced cytidine deaminase (AID) is strongly expressed in the fetal bovine ileal Peyer's patch and spleen and is associated with expansion of the primary antibody repertoire in the absence of exogenous antigens.

PubMed

Liljavirta, J; Ekman, A; Knight, J S; Pernthaner, A; Iivanainen, A; Niku, M

2013-09-01

Due to a limited range of immunoglobulin (Ig) genes, cattle and several other domestic animals rely on postrecombinatorial amplification of the primary repertoire. We report that activation-induced cytidine deaminase (AID) is strongly expressed in the fetal bovine ileal Peyer's patch and spleen but not in fetal bone marrow. The numbers of IGHV (immunoglobulin heavy chain variable) mutations correlate with AID expression. The mutational profile in the fetuses is similar to postnatal and immunized calves, with targeting of complementarity-determining region (CDR) over framework region (FR), preference of replacement over silent mutations in CDRs but not in FRs, and targeting of the AID hotspot motif RGYW/WRCY. Statistical analysis indicates negative selection on FRs and positive selection on CDRs. Our results suggest that AID-mediated somatic hypermutation and selection take place in bovine fetuses, implying a role for AID in the diversification of the primary antibody repertoire in the absence of exogenous antigens.
Psychosocial Factors Influencing Smokeless Tobacco Use by Teenage Military Dependents

DTIC Science & Technology

1994-01-01

age and grade Demographics both show strong bivariate relationships with the outcome MALE-male gender measures, we selected to use only one of these...a positive sign indicating a direct relation- no impact for either gender . Attitude and other tobacco influ- ship and a negative sign an inverse...by both genders . nlficant. However, if the interval includes one but is highly For both genders , the strongest explanatory variable for trial skewed

Sexual selection gradients change over time in a simultaneous hermaphrodite

PubMed Central

Hoffer, Jeroen NA; Mariën, Janine; Ellers, Jacintha; Koene, Joris M

2017-01-01

Sexual selection is generally predicted to act more strongly on males than on females. The Darwin-Bateman paradigm predicts that this should also hold for hermaphrodites. However, measuring this strength of selection is less straightforward when both sexual functions are performed throughout the organism’s lifetime. Besides, quantifications of sexual selection are usually done during a short time window, while many animals store sperm and are long-lived. To explore whether the chosen time frame affects estimated measures of sexual selection, we recorded mating success and reproductive success over time, using a simultaneous hermaphrodite. Our results show that male sexual selection gradients are consistently positive. However, an individual’s female mating success seems to negatively affect its own male reproductive success, an effect that only becomes visible several weeks into the experiment, highlighting that the time frame is crucial for the quantification and interpretation of sexual selection measures, an insight that applies to any iteroparous mating system. DOI: http://dx.doi.org/10.7554/eLife.25139.001 PMID:28613158
Distinct Trajectories of Massive Recent Gene Gains and Losses in Populations of a Microbial Eukaryotic Pathogen

PubMed Central

Hartmann, Fanny E.; Croll, Daniel

2017-01-01

Abstract Differences in gene content are a significant source of variability within species and have an impact on phenotypic traits. However, little is known about the mechanisms responsible for the most recent gene gains and losses. We screened the genomes of 123 worldwide isolates of the major pathogen of wheat Zymoseptoria tritici for robust evidence of gene copy number variation. Based on orthology relationships in three closely related fungi, we identified 599 gene gains and 1,024 gene losses that have not yet reached fixation within the focal species. Our analyses of gene gains and losses segregating in populations showed that gene copy number variation arose preferentially in subtelomeres and in proximity to transposable elements. Recently lost genes were enriched in virulence factors and secondary metabolite gene clusters. In contrast, recently gained genes encoded mostly secreted protein lacking a conserved domain. We analyzed the frequency spectrum at loci segregating a gene presence–absence polymorphism in four worldwide populations. Recent gene losses showed a significant excess in low-frequency variants compared with genome-wide single nucleotide polymorphism, which is indicative of strong negative selection against gene losses. Recent gene gains were either under weak negative selection or neutral. We found evidence for strong divergent selection among populations at individual loci segregating a gene presence–absence polymorphism. Hence, gene gains and losses likely contributed to local adaptation. Our study shows that microbial eukaryotes harbor extensive copy number variation within populations and that functional differences among recently gained and lost genes led to distinct evolutionary trajectories. PMID:28981698
Multivariate sexual selection on male tegmina in wild populations of sagebrush crickets, Cyphoderris strepitans (Orthoptera: Haglidae).

PubMed

Ower, G D; Hunt, J; Sakaluk, S K

2017-02-01

Although the strength and form of sexual selection on song in male crickets have been studied extensively, few studies have examined selection on the morphological structures that underlie variation in males' song, particularly in wild populations. Geometric morphometric techniques were used to measure sexual selection on the shape, size and symmetry of both top and bottom tegmina in wild populations of sagebrush crickets, a species in which nuptial feeding by females imposes an unambiguous phenotypic marker on males. The size of the tegmina negatively covaried with song dominant frequency and positively covaried with song pulse duration. Sexual selection was more intense on the bottom tegmen, conceivably because it interacts more freely with the subtegminal airspace, which may play a role in song amplification. An expanded coastal/subcostal region was one of the phenotypes strongly favoured by disruptive selection on the bottom tegmen, an adaptation that may form a more effective seal with the thorax to prevent noise cancellation. Directional selection also favoured increased symmetry in tegminal shape. Assuming more symmetrical males are better able to buffer against developmental noise, the song produced by these males may make them more attractive to females. Despite the strong stabilizing selection documented previously on the dominant frequency of the song, stabilizing selection on the resonator that regulates dominant frequency was surprisingly absent. Nonetheless, wing morphology had an important influence on song structure and appears to be subject to significant linear and nonlinear sexual selection through female mate choice. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.
Radiative PQ breaking and the Higgs boson mass

NASA Astrophysics Data System (ADS)

D'Eramo, Francesco; Hall, Lawrence J.; Pappadopulo, Duccio

2015-06-01

The small and negative value of the Standard Model Higgs quartic coupling at high scales can be understood in terms of anthropic selection on a landscape where large and negative values are favored: most universes have a very short-lived electroweak vacuum and typical observers are in universes close to the corresponding metastability boundary. We provide a simple example of such a landscape with a Peccei-Quinn symmetry breaking scale generated through dimensional transmutation and supersymmetry softly broken at an intermediate scale. Large and negative contributions to the Higgs quartic are typically generated on integrating out the saxion field. Cancellations among these contributions are forced by the anthropic requirement of a sufficiently long-lived electroweak vacuum, determining the multiverse distribution for the Higgs quartic in a similar way to that of the cosmological constant. This leads to a statistical prediction of the Higgs boson mass that, for a wide range of parameters, yields the observed value within the 1σ statistical uncertainty of ˜ 5 GeV originating from the multiverse distribution. The strong CP problem is solved and single-component axion dark matter is predicted, with an abundance that can be understood from environmental selection. A more general setting for the Higgs mass prediction is discussed.
Variations in the promoter region of the serotonin transporter gene and biased attention for emotional information: a meta-analysis.

PubMed

Pergamin-Hight, Lee; Bakermans-Kranenburg, Marian J; van Ijzendoorn, Marinus H; Bar-Haim, Yair

2012-02-15

Selective attention to negative information has been strongly implicated in the etiology and maintenance of anxiety and offered as a potential intermediate phenotype for anxiety disorders. Attention biases have been studied in relation to a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) offering equivocal findings. The present meta-analysis tested whether the extant published data support the notion that variation in the 5-HTTLPR genotype modulates selective attention to negative information. Eleven relevant samples from 10 published articles were identified through a systematic literature search (total n = 807). Relevant attention bias and 5-HTTLPR data were extracted based on specific coding rules, and Cohen's d effect size index was used to calculate all outcome measures. Publication bias was assessed using various methods. Carriers of the low (SS, SL(G), L(G)L(G)) transmission efficacy genotype display attentional vigilance toward negatively valenced stimuli, a pattern not found in the intermediate (SL(A), L(A)L(G)) and high (L(A)L(A)) efficacy genotypes. This phenomenon emerges as of medium effect size. The meta-analysis supports the notion that allele variants of the 5-HTTLPR are associated with selective attention to negative stimuli. More studies are needed to fully establish the consistency of this effect. Future studies applying systematic attention bias modification may shed further light on the role of 5-HTTLPR in the development of anxiety disorders and in the prediction of clinical response to attention bias modification treatments. Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
Neural processing of negative word stimuli concerning body image in patients with eating disorders: an fMRI study.

PubMed

Miyake, Yoshie; Okamoto, Yasumasa; Onoda, Keiichi; Shirao, Naoko; Okamoto, Yuri; Otagaki, Yoko; Yamawaki, Shigeto

2010-04-15

Eating disorders (EDs) are associated with abnormalities of body image perception. The aim of the present study was to investigate the functional abnormalities in brain systems during processing of negative words concerning body images in patients with EDs. Brain responses to negative words concerning body images (task condition) and neutral words (control condition) were measured using functional magnetic resonance imaging in 36 patients with EDs (12 with the restricting type anorexia nervosa; AN-R, 12 with the binging-purging type anorexia nervosa; AN-BP, and 12 with bulimia nervosa; BN) and 12 healthy young women. Participants were instructed to select the most negative word from each negative body-image word set and to select the most neutral word from each neutral word set. In the task relative to the control condition, the right amygdala was activated both in patients with AN-R and in patients with AN-BP. The left medial prefrontal cortex (mPFC) was activated both in patients with BN and in patients with AN-BP. It is suggested that these brain activations may be associated with abnormalities of body image perception. Amygdala activation may be involved in fearful emotional processing of negative words concerning body image and strong fears of gaining weight. One possible interpretation of the finding of mPFC activation is that it may reflect an attempt to regulate the emotion invoked by the stimuli. These abnormal brain functions may help provide better accounts of the psychopathological mechanisms underlying EDs. Copyright 2009 Elsevier Inc. All rights reserved.
Characteristics of feed efficiency within and across lactation in dairy cows and the effect of genetic selection.

PubMed

Hurley, A M; Lopez-Villalobos, N; McParland, S; Lewis, E; Kennedy, E; O'Donovan, M; Burke, J L; Berry, D P

2018-02-01

The objective of the present study was to investigate the phenotypic inter- and intra-relationships within and among alternative feed efficiency metrics across different stages of lactation and parities; the expected effect of genetic selection for feed efficiency on the resulting phenotypic lactation profiles was also quantified. A total of 8,199 net energy intake (NE I ) test-day records from 2,505 lactations on 1,290 cows were used. Derived efficiency traits were either ratio based or residual based; the latter were derived from least squares regression models. Residual energy intake (REI) was defined as NE I minus predicted energy requirements based on lactation performance; residual energy production (REP) was defined as net energy for lactation minus predicted energy requirements based on lactation performance. Energy conversion efficiency was defined as net energy for lactation divided by NE I . Pearson phenotypic correlations among traits were computed across lactation stages and parities, and the significance of the differences was determined using the Fisher r-to-z transformation. Sources of variation in the feed efficiency metrics were investigated using linear mixed models, which included the fixed effects of contemporary group, breed, parity, stage of lactation, and the 2-way interaction of parity by stage of lactation. With the exception of REI, parity was associated with all efficiency and production traits. Stage of lactation, as well as the 2-way interaction of parity by stage of lactation, were associated with all efficiency and production traits. Phenotypic correlations among the efficiency and production traits differed not only by stage of lactation but also by parity. For example, the strong phenotypic correlation between REI and energy balance (EB; 0.89) for cows in parity 3 or greater and early lactation was weaker for parity 1 cows at the same lactation stage (0.81), suggesting primiparous cows use the ingested energy for both milk production and growth. Nonetheless, these strong phenotypic correlations between REI and EB suggested negative REI animals (i.e., more efficient) are also in more negative EB. These correlations were further supported when assessing the effect on phenotypic performance of animals genetically divergent for feed intake and efficiency based on parental average. Animals genetically selected to have lower REI resulted in cows who consumed less NE I but were also in negative EB throughout the entire lactation. Nonetheless, such repercussions of negative EB do not imply that selection for negative REI (as defined here) should not be practiced, but instead should be undertaken within the framework of a balanced breeding objective, which includes traits such as reproduction and health. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Evolution of CRISPs associated with toxicoferan-reptilian venom and mammalian reproduction.

PubMed

Sunagar, Kartik; Johnson, Warren E; O'Brien, Stephen J; Vasconcelos, Vítor; Antunes, Agostinho

2012-07-01

Cysteine-rich secretory proteins (CRISPs) are glycoproteins found exclusively in vertebrates and have broad diversified functions. They are hypothesized to play important roles in mammalian reproduction and in reptilian venom, where they disrupt homeostasis of the prey through several mechanisms, including among others, blockage of cyclic nucleotide-gated and voltage-gated ion channels and inhibition of smooth muscle contraction. We evaluated the molecular evolution of CRISPs in toxicoferan reptiles at both nucleotide and protein levels relative to their nonvenomous mammalian homologs. We show that the evolution of CRISP gene in these reptiles is significantly influenced by positive selection and in snakes (ω = 3.84) more than in lizards (ω = 2.33), whereas mammalian CRISPs were under strong negative selection (CRISP1 = 0.55, CRISP2 = 0.40, and CRISP3 = 0.68). The use of ancestral sequence reconstruction, mapping of mutations on the three-dimensional structure, and detailed evaluation of selection pressures suggests that the toxicoferan CRISPs underwent accelerated evolution aided by strong positive selection and directional mutagenesis, whereas their mammalian homologs are constrained by negative selection. Gene and protein-level selection analyses identified 41 positively selected sites in snakes and 14 sites in lizards. Most of these sites are located on the molecular surface (nearly 76% in snakes and 79% in lizards), whereas the backbone of the protein retains a highly conserved structural scaffold. Nearly 46% of the positively selected sites occur in the cysteine-rich domain of the protein. This directional mutagenesis, where the hotspots of mutations are found on the molecular surface and functional domains of the protein, acts as a diversifying mechanism for the exquisite biological targeting of CRISPs in toxicoferan reptiles. Finally, our analyses suggest that the evolution of toxicoferan-CRISP venoms might have been influenced by the specific predatory mechanism employed by the organism. CRISPs in Elapidae, which mostly employ neurotoxins, have experienced less positive selection pressure (ω = 2.86) compared with the "nonvenomous" colubrids (ω = 4.10) that rely on grip and constriction to capture the prey, and the Viperidae, a lineage that mostly employs haemotoxins (ω = 4.19). Relatively lower omega estimates in Anguimorph lizards (ω = 2.33) than snakes (ω = 3.84) suggests that lizards probably depend more on pace and powerful jaws for predation than venom.
Topology of evolving, mutagenized viral populations: quasispecies expansion, compression, and operation of negative selection.

PubMed

Ojosnegros, Samuel; Agudo, Rubén; Sierra, Macarena; Briones, Carlos; Sierra, Saleta; González-López, Claudia; Domingo, Esteban; Cristina, Juan

2008-07-17

The molecular events and evolutionary forces underlying lethal mutagenesis of virus (or virus extinction through an excess of mutations) are not well understood. Here we apply for the first time phylogenetic methods and Partition Analysis of Quasispecies (PAQ) to monitor genetic distances and intra-population structures of mutant spectra of foot-and-mouth disease virus (FMDV) quasispecies subjected to mutagenesis by base and nucleoside analogues. Phylogenetic and PAQ analyses have revealed a highly dynamic variation of intrapopulation diversity of FMDV quasispecies. The population diversity first suffers striking expansions in the presence of mutagens and then compressions either when the presence of the mutagenic analogue was discontinued or when a mutation that decreased sensitivity to a mutagen was selected. The pattern of mutations found in the populations was in agreement with the behavior of the corresponding nucleotide analogues with FMDV in vitro. Mutations accumulated at preferred genomic sites, and dn/ds ratios indicate the operation of negative (or purifying) selection in populations subjected to mutagenesis. No evidence of unusually elevated genetic distances has been obtained for FMDV populations approaching extinction. Phylogenetic and PAQ analysis provide adequate procedures to describe the evolution of viral sequences subjected to lethal mutagenesis. These methods define the changes of intra-population structure more precisely than mutation frequencies and Shannon entropies. PAQ is very sensitive to variations of intrapopulation genetic distances. Strong negative (or purifying) selection operates in FMDV populations subjected to enhanced mutagenesis. The quantifications provide evidence that extinction does not imply unusual increases of intrapopulation complexity, in support of the lethal defection model of virus extinction.
A networked voting rule for democratic representation

PubMed Central

Brigatti, Edgardo; Moreno, Yamir

2018-01-01

We introduce a general framework for exploring the problem of selecting a committee of representatives with the aim of studying a networked voting rule based on a decentralized large-scale platform, which can assure a strong accountability of the elected. The results of our simulations suggest that this algorithm-based approach is able to obtain a high representativeness for relatively small committees, performing even better than a classical voting rule based on a closed list of candidates. We show that a general relation between committee size and representatives exists in the form of an inverse square root law and that the normalized committee size approximately scales with the inverse of the community size, allowing the scalability to very large populations. These findings are not strongly influenced by the different networks used to describe the individuals’ interactions, except for the presence of few individuals with very high connectivity which can have a marginal negative effect in the committee selection process. PMID:29657817
Impact of emotional maltreatment on self esteem among adolescents.

PubMed

Malik, Sadia; Kaiser, Aneeqa

2016-07-01

To investigate the impact of emotional maltreatment on self-esteem among adolescents, and to see if gender makes a difference in this context. The cross-sectional study was conducted from January to April 2014, and comprised adolescents in the age range of 14 to 18 years who were selected using purposive sampling from various government and private schools and colleges of Sargodha, Punjab. The questionnaire on seven dimensions of emotional maltreatment at home and Rosenberg self-esteem scale were used. There were 400 subjects; 200(50%) boys and as many girls. The overall mean age was 16.14±1.36 years (range: 14-18 years). Correlation coefficient indicated significant negative relationship between emotional maltreatment and self-esteem (degrading r= -0.33, p<0.01; exploitation r= -0.30, p< 0.01; isolating r=-0.36, p<0.01; ignoring r= -0.32, p<0.01; rejecting r=-0.43, p< 0.01; and terrorizing r= -0.35, p<0.01) among students. Emotional maltreatment strongly predicted negative self-esteem (isolating?= -0.12, p<0.05; and rejecting ?= -0.30, p< 0.001) among adolescents. Findings indicated significant gender differences in degrading component of emotional maltreatment and self-esteem. Emotional maltreatment strongly predicted negative self-esteem among adolescents. Gender was a significant factor in the domain of degrading.
Effect of insecticide resistance on development, longevity and reproduction of field or laboratory selected Aedes aegypti populations.

PubMed

Martins, Ademir Jesus; Ribeiro, Camila Dutra e Mello; Bellinato, Diogo Fernandes; Peixoto, Alexandre Afranio; Valle, Denise; Lima, José Bento Pereira

2012-01-01

Aedes aegypti dispersion is the major reason for the increase in dengue transmission in South America. In Brazil, control of this mosquito strongly relies on the use of pyrethroids and organophosphates against adults and larvae, respectively. In consequence, many Ae. aegypti field populations are resistant to these compounds. Resistance has a significant adaptive value in the presence of insecticide treatment. However some selected mechanisms can influence important biological processes, leading to a high fitness cost in the absence of insecticide pressure. We investigated the dynamics of insecticide resistance and its potential fitness cost in five field populations and in a lineage selected for deltamethrin resistance in the laboratory, for nine generations. For all populations the life-trait parameters investigated were larval development, sex ratio, adult longevity, relative amount of ingested blood, rate of ovipositing females, size of egglaying and eggs viability. In the five natural populations, the effects on the life-trait parameters were discrete but directly proportional to resistance level. In addition, several viability parameters were strongly affected in the laboratory selected population compared to its unselected control. Our results suggest that mechanisms selected for organophosphate and pyrethroid resistance caused the accumulation of alleles with negative effects on different life-traits and corroborate the hypothesis that insecticide resistance is associated with a high fitness cost.
Effect of Insecticide Resistance on Development, Longevity and Reproduction of Field or Laboratory Selected Aedes aegypti Populations

PubMed Central

Bellinato, Diogo Fernandes; Peixoto, Alexandre Afranio; Valle, Denise; Lima, José Bento Pereira

2012-01-01

Aedes aegypti dispersion is the major reason for the increase in dengue transmission in South America. In Brazil, control of this mosquito strongly relies on the use of pyrethroids and organophosphates against adults and larvae, respectively. In consequence, many Ae. aegypti field populations are resistant to these compounds. Resistance has a significant adaptive value in the presence of insecticide treatment. However some selected mechanisms can influence important biological processes, leading to a high fitness cost in the absence of insecticide pressure. We investigated the dynamics of insecticide resistance and its potential fitness cost in five field populations and in a lineage selected for deltamethrin resistance in the laboratory, for nine generations. For all populations the life-trait parameters investigated were larval development, sex ratio, adult longevity, relative amount of ingested blood, rate of ovipositing females, size of egglaying and eggs viability. In the five natural populations, the effects on the life-trait parameters were discrete but directly proportional to resistance level. In addition, several viability parameters were strongly affected in the laboratory selected population compared to its unselected control. Our results suggest that mechanisms selected for organophosphate and pyrethroid resistance caused the accumulation of alleles with negative effects on different life-traits and corroborate the hypothesis that insecticide resistance is associated with a high fitness cost. PMID:22431967
Valley-selective Landau-Zener oscillations in semi-Dirac p -n junctions

NASA Astrophysics Data System (ADS)

Saha, K.; Nandkishore, R.; Parameswaran, S. A.

2017-07-01

We study transport across p -n junctions of gapped two-dimensional semi-Dirac materials: nodal semimetals whose energy bands disperse quadratically and linearly along distinct crystal axes. The resulting electronic properties—relevant to materials such as TiO2/VO2 multilayers and α -(BEDT-TTF)2I3 salts—continuously interpolate between those of mono- and bilayer graphene as a function of propagation angle. We demonstrate that tunneling across the junction depends on the orientation of the tunnel barrier relative to the crystalline axes, leading to strongly nonmonotonic current-voltage characteristics, including negative differential conductance in some regimes. In multivalley systems, these features provide a natural route to engineering valley-selective transport.
Selecting habitat to survive: the impact of road density on survival in a large carnivore.

PubMed

Basille, Mathieu; Van Moorter, Bram; Herfindal, Ivar; Martin, Jodie; Linnell, John D C; Odden, John; Andersen, Reidar; Gaillard, Jean-Michel

2013-01-01

Habitat selection studies generally assume that animals select habitat and food resources at multiple scales to maximise their fitness. However, animals sometimes prefer habitats of apparently low quality, especially when considering the costs associated with spatially heterogeneous human disturbance. We used spatial variation in human disturbance, and its consequences on lynx survival, a direct fitness component, to test the Hierarchical Habitat Selection hypothesis from a population of Eurasian lynx Lynx lynx in southern Norway. Data from 46 lynx monitored with telemetry indicated that a high proportion of forest strongly reduced the risk of mortality from legal hunting at the home range scale, while increasing road density strongly increased such risk at the finer scale within the home range. We found hierarchical effects of the impact of human disturbance, with a higher road density at a large scale reinforcing its negative impact at a fine scale. Conversely, we demonstrated that lynx shifted their habitat selection to avoid areas with the highest road densities within their home ranges, thus supporting a compensatory mechanism at fine scale enabling lynx to mitigate the impact of large-scale disturbance. Human impact, positively associated with high road accessibility, was thus a stronger driver of lynx space use at a finer scale, with home range characteristics nevertheless constraining habitat selection. Our study demonstrates the truly hierarchical nature of habitat selection, which aims at maximising fitness by selecting against limiting factors at multiple spatial scales, and indicates that scale-specific heterogeneity of the environment is driving individual spatial behaviour, by means of trade-offs across spatial scales.
Bullying victimization prevalence and its effects on psychosomatic complaints: can sense of coherence make a difference?

PubMed

García-Moya, Irene; Suominen, Sakari; Moreno, Carmen

2014-10-01

The aim of this study was to examine the prevalence of bullying victimization and its impact on physical and psychological complaints in a representative sample of adolescents and to explore the role of sense of coherence (SOC) in victimization prevalence and consequences. A representative sample of Spanish adolescents (N = 7580, mean age = 15.41) was selected as part of the Health Behaviour in School-aged Children study. Bullying victimization, physical and psychological symptoms, and SOC were measured, and comparisons were made between strong- and weak-SOC adolescents regarding their likelihood of being a victim of bullying and the negative effects of bullying victimization on their health. Weak-SOC adolescents were significantly more likely to suffer from bullying victimization regardless of type (nonphysical vs physical and nonphysical) or means (traditional vs cyberbullying). In addition, bullying victimization showed significant increasing effects on weak-SOC adolescents' physical and psychological symptoms whereas in strong-SOC adolescents it was not significantly associated with increases in physical complaints and its effects on psychological complaints seemed to be weaker. Weak-SOC adolescents seem to be at higher risk of becoming bullying victims and victimization experiences appear to have increased negative effects on them when compared to strong-SOC students. © 2014, American School Health Association.
Monitoring of vegetation condition using the NDVI/ENSO anomalies in Central Asia and their relationships with ONI (very strong) phases

NASA Astrophysics Data System (ADS)

Aralova, Dildora; Toderich, Kristina; Jarihani, Ben; Gafurov, Dilshod; Gismatulina, Liliya

2016-10-01

An investigation of temporal dynamics of El Niño-Southern Oscillation (ENSO) and spatial patterns of dryness/wetness period over arid and semi-arid zones of Central Asia and their relationship with Normalized Difference Vegetation Index (NDVI) values (1982-2011) have explored in this article. For identifying periodical oscillations and their relationship with NDVI values have selected El Nino 3.4 index and thirty years of new generation bi-weekly NDVI 3g acquired by the Advanced Very High Resolution Radiometer (AVHRR) satellites time-series data. Based on identification ONI (Oceanic Nino Index) is a very strong El Nino (warm) anomalies observed during 1982-1983, 1997-1998 and very strong La Nino (cool) period events have observed 1988-1989 years. For correlation these two factors and seeking positive and negative trends it has extracted from NDVI time series data as "low productivity period" following years: 1982-1983, 1997 -1998; and as "high productivity period" following years: 1988 -1989. Linear regression observed warm events as moderate phase period selected between moderate El Nino (ME) and NDVI with following periods:1986-1987; 1987-1988; 1991-1992; 2002-2003; 2009-2010; and moderate La Niña (ML) periods and NDVI (1998-1999; 1999-2000; 2007-2008) which has investigated a spatial patterns of wetness conditions. The results indicated that an inverse relationship between very strong El Nino and NDVI, decreased vegetation response with larger positive ONI value; and direct relationship between very strong La Niña and NDVI, increased vegetation response with smaller negative ONI value. Results assumed that significant impact of these anomalies influenced on vegetation productivity. These results will be a beneficial for efficient rangeland/grassland management and to propose drought periods for assessment and reducing quantity of flocks' due to a lack of fodder biomass for surviving livestock flocks on upcoming years in rangelands. Also results demonstrate that a non-anthropogenic drivers of variability effected to land surface vegetation signals, understanding of which will be beneficial for efficient rangeland and agriculture management and establish ecosystem services in precipitation-driven drylands of Central Asia.
Distinct Trajectories of Massive Recent Gene Gains and Losses in Populations of a Microbial Eukaryotic Pathogen.

PubMed

Hartmann, Fanny E; Croll, Daniel

2017-11-01

Differences in gene content are a significant source of variability within species and have an impact on phenotypic traits. However, little is known about the mechanisms responsible for the most recent gene gains and losses. We screened the genomes of 123 worldwide isolates of the major pathogen of wheat Zymoseptoria tritici for robust evidence of gene copy number variation. Based on orthology relationships in three closely related fungi, we identified 599 gene gains and 1,024 gene losses that have not yet reached fixation within the focal species. Our analyses of gene gains and losses segregating in populations showed that gene copy number variation arose preferentially in subtelomeres and in proximity to transposable elements. Recently lost genes were enriched in virulence factors and secondary metabolite gene clusters. In contrast, recently gained genes encoded mostly secreted protein lacking a conserved domain. We analyzed the frequency spectrum at loci segregating a gene presence-absence polymorphism in four worldwide populations. Recent gene losses showed a significant excess in low-frequency variants compared with genome-wide single nucleotide polymorphism, which is indicative of strong negative selection against gene losses. Recent gene gains were either under weak negative selection or neutral. We found evidence for strong divergent selection among populations at individual loci segregating a gene presence-absence polymorphism. Hence, gene gains and losses likely contributed to local adaptation. Our study shows that microbial eukaryotes harbor extensive copy number variation within populations and that functional differences among recently gained and lost genes led to distinct evolutionary trajectories. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
Bim-mediated apoptosis is not necessary for thymic negative selection to ubiquitous self-antigens.

PubMed

Hu, Qian; Sader, Alyssa; Parkman, Julia C; Baldwin, Troy A

2009-12-15

T cell education in the thymus is critical for establishing a functional, yet self-tolerant, T cell repertoire. Negative selection is a key process in enforcing self-tolerance. There are many questions that surround the mechanism of negative selection, but it is currently held that apoptosis initiated by Bim and/or Nur77 is critical for negative selection. Recent studies, however, have questioned the necessity of Bim in maintaining both central and peripheral T cell tolerance. To reconcile these apparently contradictory findings, we examined the role of Bim in negative selection in the well-characterized, physiological HY(cd4) mouse model. We found that while Bim expression was required for CD4(+)CD8(+) double-positive thymocyte apoptosis, it was not required for negative selection. Furthermore, Bim deficiency did not alter the frequency or affinity of male reactive cells that escape negative selection in an oligoclonal repertoire. Collectively, these studies indicate that negative selection occurs efficiently in the absence of apoptosis and suggest that the current paradigm of negative selection requiring apoptosis be revisited.
Unusual transformation from strong negative to positive thermal expansion in PbTiO3-BiFeO3 perovskite.

PubMed

Chen, Jun; Fan, Longlong; Ren, Yang; Pan, Zhao; Deng, Jinxia; Yu, Ranbo; Xing, Xianran

2013-03-15

Tetragonal PbTiO(3)-BiFeO(3) exhibits a strong negative thermal expansion in the PbTiO(3)-based ferroelectrics that consist of one branch in the family of negative thermal expansion materials. Its strong negative thermal expansion is much weakened, and then unusually transforms into positive thermal expansion as the particle size is slightly reduced. This transformation is a new phenomenon in the negative termal expansion materials. The detailed structure, temperature dependence of unit cell volume, and lattice dynamics of PbTiO(3)-BiFeO(3) samples were studied by means of high-energy synchrotron powder diffraction and Raman spectroscopy. Such unusual transformation from strong negative to positive thermal expansion is highly associated with ferroelectricity weakening. An interesting zero thermal expansion is achieved in a wide temperature range (30-500 °C) by adjusting particle size due to the negative-to-positive transformation character. The present study provides a useful method to control the negative thermal expansion not only for ferroelectrics but also for those functional materials such as magnetics and superconductors.

Debunking vaccination myths: strong risk negations can increase perceived vaccination risks.

PubMed

Betsch, Cornelia; Sachse, Katharina

2013-02-01

Information about risks is often contradictory, especially in the health domain. A vast amount of bizarre information on vaccine-adverse events (VAE) can be found on the Internet; most are posted by antivaccination activists. Several actors in the health sector struggle against these statements by negating claimed risks with scientific explanations. The goal of the present work is to find optimal ways of negating risk to decrease risk perceptions. In two online experiments, we varied the extremity of risk negations and their source. Perception of the probability of VAE, their expected severity (both variables serve as indicators of perceived risk), and vaccination intentions. Paradoxically, messages strongly indicating that there is "no risk" led to a higher perceived vaccination risk than weak negations. This finding extends previous work on the negativity bias, which has shown that information stating the presence of risk decreases risk perceptions, while information negating the existence of risk increases such perceptions. Several moderators were also tested; however, the effect occurred independently of the number of negations, recipient involvement, and attitude. Solely the credibility of the information source interacted with the extremity of risk negation: For credible sources (governmental institutions), strong and weak risk negations lead to similar perceived risk, while for less credible sources (pharmaceutical industries) weak negations lead to less perceived risk than strong negations. Optimal risk negation may profit from moderate rather than extreme formulations as a source's trustworthiness can vary.
The selective determination of sulfates, sulfonates, and phosphates in urine by capillary electrophoresis/mass spectrometry.

PubMed

Bunz, Svenja-Catharina; Neusüß, Christian

2013-01-01

Metabolite identification and metabolite profiling are of major importance in the pharmaceutical and clinical context. However, anions of biological relevance such as sulfates, sulfonates, and phosphates are rarely included in common techniques for metabolite studies. In this protocol, we demonstrate a unique method to selectively determine these anions. The method comprises a capillary electrophoresis separation using an acidic background electrolyte (pH ≤ 2) and anodic detection by mass spectrometry via negative electrospray ionization. In this way, only anions of strong acids like sulfates are determined. The selectivity for sulfur-containing species is proved based on the specific isotopic ratios. In conjunction with the accurate mass from the time-of-flight mass spectrometer, the presented method is well suited for clinical and pharmaceutical applications to identify possible metabolites and to quantify known metabolites.
Identification and analysis of evolutionary selection pressures acting at the molecular level in five forkhead subfamilies.

PubMed

Fetterman, Christina D; Rannala, Bruce; Walter, Michael A

2008-09-24

Members of the forkhead gene family act as transcription regulators in biological processes including development and metabolism. The evolution of forkhead genes has not been widely examined and selection pressures at the molecular level influencing subfamily evolution and differentiation have not been explored. Here, in silico methods were used to examine selection pressures acting on the coding sequence of five multi-species FOX protein subfamily clusters; FoxA, FoxD, FoxI, FoxO and FoxP. Application of site models, which estimate overall selection pressures on individual codons throughout the phylogeny, showed that the amino acid changes observed were either neutral or under negative selection. Branch-site models, which allow estimated selection pressures along specified lineages to vary as compared to the remaining phylogeny, identified positive selection along branches leading to the FoxA3 and Protostomia clades in the FoxA cluster and the branch leading to the FoxO3 clade in the FoxO cluster. Residues that may differentiate paralogs were identified in the FoxA and FoxO clusters and residues that differentiate orthologs were identified in the FoxA cluster. Neutral amino acid changes were identified in the forkhead domain of the FoxA, FoxD and FoxP clusters while positive selection was identified in the forkhead domain of the Protostomia lineage of the FoxA cluster. A series of residues under strong negative selection adjacent to the N- and C-termini of the forkhead domain were identified in all clusters analyzed suggesting a new method for refinement of domain boundaries. Extrapolation of domains among cluster members in conjunction with selection pressure information allowed prediction of residue function in the FoxA, FoxO and FoxP clusters and exclusion of known domain function in residues of the FoxA and FoxI clusters. Consideration of selection pressures observed in conjunction with known functional information allowed prediction of residue function and refinement of domain boundaries. Identification of residues that differentiate orthologs and paralogs provided insight into the development and functional consequences of paralogs and forkhead subfamily composition differences among species. Overall we found that after gene duplication of forkhead family members, rapid differentiation and subsequent fixation of amino acid changes through negative selection has occurred.
Strong monogamy conjecture in a four-qubit system

NASA Astrophysics Data System (ADS)

Karmakar, Sumana; Sen, Ajoy; Bhar, Amit; Sarkar, Debasis

2016-01-01

Monogamy is a defining feature of entanglement, having far-reaching applications. Recently, Regula et al. [Phys. Rev. Lett. 113, 110501 (2014), 10.1103/PhysRevLett.113.110501] proposed a stronger version of monogamy relation for concurrence. We have extended the strong monogamy inequality for another entanglement measure, viz., negativity. In particular, we have concentrated on the four-qubit system and provided a detailed study on the status of strong monogamy on pure states. Further, we have analytically provided some classes of states for which negativity and squared negativity satisfy strong monogamy. Numerical evidences have also been shown in proper places. Our analysis also provides cases where strong monogamy is violated.
Ion Selectivity Mechanism in a Bacterial Pentameric Ligand-Gated Ion Channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fritsch, Sebastian; Ivanov, Ivaylo; Wang, Hailong

2010-01-01

The proton-gated ion channel from Gloeobacter violaceus (GLIC) is a prokaryotic homolog of the eukaryotic nicotinic acetylcholine receptor that responds to the binding of neurotransmitter acetylcholine and mediates fast signal transmission. Recent emergence of a high-resolution crystal structure of GLIC captured in a potentially open state allowed detailed, atomic-level insight into ion conduction and selectivity mechanisms in these channels. Herein, we have examined the barriers to ion conduction and origins of ion selectivity in the GLIC channel by the construction of potential-of-mean-force profiles for sodium and chloride ions inside the transmembrane region. Our calculations reveal that the GLIC channel ismore » open for a sodium ion to transport, but presents a 11 kcal/mol free energy barrier for a chloride ion. Our collective findings identify three distinct contributions to the observed preference for the permeant ions. First, there is a substantial contribution due to a ring of negatively charged glutamate residues (E-2 ) at the narrow intracellular end of the channel. The negative electrostatics of this region and the ability of the glutamate side chains to directly bind cations would strongly favor the passage of sodium ions while hindering translocation of chloride ions. Second, our results imply a significant hydrophobic contribution to selectivity linked to differences in the desolvation penalty for the sodium versus chloride ions in the central hydrophobic region of the pore. This hydrophobic contribution is evidenced by the large free energy barriers experienced by Cl in the middle of the pore for both GLIC and the E-2 A mutant. Finally, there is a distinct contribution arising from the overall negative electrostatics of the channel.« less
Topology of evolving, mutagenized viral populations: quasispecies expansion, compression, and operation of negative selection

PubMed Central

2008-01-01

Background The molecular events and evolutionary forces underlying lethal mutagenesis of virus (or virus extinction through an excess of mutations) are not well understood. Here we apply for the first time phylogenetic methods and Partition Analysis of Quasispecies (PAQ) to monitor genetic distances and intra-population structures of mutant spectra of foot-and-mouth disease virus (FMDV) quasispecies subjected to mutagenesis by base and nucleoside analogues. Results Phylogenetic and PAQ analyses have revealed a highly dynamic variation of intrapopulation diversity of FMDV quasispecies. The population diversity first suffers striking expansions in the presence of mutagens and then compressions either when the presence of the mutagenic analogue was discontinued or when a mutation that decreased sensitivity to a mutagen was selected. The pattern of mutations found in the populations was in agreement with the behavior of the corresponding nucleotide analogues with FMDV in vitro. Mutations accumulated at preferred genomic sites, and dn/ds ratios indicate the operation of negative (or purifying) selection in populations subjected to mutagenesis. No evidence of unusually elevated genetic distances has been obtained for FMDV populations approaching extinction. Conclusion Phylogenetic and PAQ analysis provide adequate procedures to describe the evolution of viral sequences subjected to lethal mutagenesis. These methods define the changes of intra-population structure more precisely than mutation frequencies and Shannon entropies. PAQ is very sensitive to variations of intrapopulation genetic distances. Strong negative (or purifying) selection operates in FMDV populations subjected to enhanced mutagenesis. The quantifications provide evidence that extinction does not imply unusual increases of intrapopulation complexity, in support of the lethal defection model of virus extinction. PMID:18637173
Sequence polymorphism in an insect RNA virus field population: A snapshot from a single point in space and time reveals stochastic differences among and within individual hosts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stenger, Drake C., E-mail: drake.stenger@ars.usda.

Population structure of Homalodisca coagulata Virus-1 (HoCV-1) among and within field-collected insects sampled from a single point in space and time was examined. Polymorphism in complete consensus sequences among single-insect isolates was dominated by synonymous substitutions. The mutant spectrum of the C2 helicase region within each single-insect isolate was unique and dominated by nonsynonymous singletons. Bootstrapping was used to correct the within-isolate nonsynonymous:synonymous arithmetic ratio (N:S) for RT-PCR error, yielding an N:S value ~one log-unit greater than that of consensus sequences. Probability of all possible single-base substitutions for the C2 region predicted N:S values within 95% confidence limits of themore » corrected within-isolate N:S when the only constraint imposed was viral polymerase error bias for transitions over transversions. These results indicate that bottlenecks coupled with strong negative/purifying selection drive consensus sequences toward neutral sequence space, and that most polymorphism within single-insect isolates is composed of newly-minted mutations sampled prior to selection. -- Highlights: •Sampling protocol minimized differential selection/history among isolates. •Polymorphism among consensus sequences dominated by negative/purifying selection. •Within-isolate N:S ratio corrected for RT-PCR error by bootstrapping. •Within-isolate mutant spectrum dominated by new mutations yet to undergo selection.« less
STRONG SOLAR WIND DYNAMIC PRESSURE PULSES: INTERPLANETARY SOURCES AND THEIR IMPACTS ON GEOSYNCHRONOUS MAGNETIC FIELDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuo, Pingbing; Feng, Xueshang; Wang, Yi

In this investigation, we first present a statistical result of the interplanetary sources of very strong solar wind dynamic pressure pulses (DPPs) detected by WIND during solar cycle 23. It is found that the vast majority of strong DPPs reside within solar wind disturbances. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears to be no systematic investigations on the response of GMFs to negative DPPs. Here, we study both the decompression effects of very strong negative DPPs and the compression from strong positive DPPs on GMFs atmore » different magnetic local time sectors. In response to the decompression of strong negative DPPs, GMFs on the dayside near dawn and near dusk on the nightside, are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of the events when GOES is located at the midnight sector, the GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that under certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here, we find that a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at the midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, which are stronger at the noon sector.« less
Population Level Purifying Selection and Gene Expression Shape Subgenome Evolution in Maize.

PubMed

Pophaly, Saurabh D; Tellier, Aurélien

2015-12-01

The maize ancestor experienced a recent whole-genome duplication (WGD) followed by gene erosion which generated two subgenomes, the dominant subgenome (maize1) experiencing fewer deletions than maize2. We take advantage of available extensive polymorphism and gene expression data in maize to study purifying selection and gene expression divergence between WGD retained paralog pairs. We first report a strong correlation in nucleotide diversity between duplicate pairs, except for upstream regions. We then show that maize1 genes are under stronger purifying selection than maize2. WGD retained genes have higher gene dosage and biased Gene Ontologies consistent with previous studies. The relative gene expression of paralogs across tissues demonstrates that 98% of duplicate pairs have either subfunctionalized in a tissuewise manner or have diverged consistently in their expression thereby preventing functional complementation. Tissuewise subfunctionalization seems to be a hallmark of transcription factors, whereas consistent repression occurs for macromolecular complexes. We show that dominant gene expression is a strong determinant of the strength of purifying selection, explaining the inferred stronger negative selection on maize1 genes. We propose a novel expression-based classification of duplicates which is more robust to explain observed polymorphism patterns than the subgenome location. Finally, upstream regions of repressed genes exhibit an enrichment in transposable elements which indicates a possible mechanism for expression divergence. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Isolation of adherent polycyclic aromatic hydrocarbon (PAH)-degrading bacteria using PAH-sorbing carriers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bastiaens, L.; Springael, D.; Wattiau, P.

Two different procedures were compared to isolate polycyclic aromatic hydrocarbon (PAH)-utilizing bacteria from PAH-contaminated soil and sludge samples, i.e., (i) shaken enrichment cultures in liquid mineral medium in which PAHs were supplied as crystals and (ii) a new method in which PAH degraders were enriched on and recovered from hydrophobic membranes containing sorbed PAHs. Both techniques were successful, but selected from the same source different bacterial strains able to grow on PAHs as the sole source of carbon and energy. The liquid enrichment mainly selected for Sphingomonas spp., whereas the membrane method exclusively led to the selection of Mycobacterium spp.more » Furthermore, in separate membrane enrichment set-ups with different membrane types, three repetitive extragenic palindromic PCR-related Mycobacterium strains were recovered. The new Mycobactereium isolates were strongly hydrophobic and displayed the capacity to adhere strongly to different surfaces. One strain, Mycobacterium sp. LB501T, displayed an unusual combination of high adhesion efficiency and an extremely high negative charge. This strain may represent a new bacterial species as suggested by 16S rRNA gene sequence analysis. These results indicate that the provision of hydrophobic sorbents containing sorbed PAHs in the enrichment procedure discriminated in favor of certain bacterial characteristics. The new isolation method is appropriate to select for adherent PAH-degrading bacteria, which might be useful to biodegrade sorbed PAHs in soils and sludge.« less
Isolation of Adherent Polycyclic Aromatic Hydrocarbon (PAH)-Degrading Bacteria Using PAH-Sorbing Carriers

PubMed Central

Bastiaens, Leen; Springael, Dirk; Wattiau, Pierre; Harms, Hauke; deWachter, Rupert; Verachtert, Hubert; Diels, Ludo

2000-01-01

Two different procedures were compared to isolate polycyclic aromatic hydrocarbon (PAH)-utilizing bacteria from PAH-contaminated soil and sludge samples, i.e., (i) shaken enrichment cultures in liquid mineral medium in which PAHs were supplied as crystals and (ii) a new method in which PAH degraders were enriched on and recovered from hydrophobic membranes containing sorbed PAHs. Both techniques were successful, but selected from the same source different bacterial strains able to grow on PAHs as the sole source of carbon and energy. The liquid enrichment mainly selected for Sphingomonas spp., whereas the membrane method exclusively led to the selection of Mycobacterium spp. Furthermore, in separate membrane enrichment set-ups with different membrane types, three repetitive extragenic palindromic PCR-related Mycobacterium strains were recovered. The new Mycobacterium isolates were strongly hydrophobic and displayed the capacity to adhere strongly to different surfaces. One strain, Mycobacterium sp. LB501T, displayed an unusual combination of high adhesion efficiency and an extremely high negative charge. This strain may represent a new bacterial species as suggested by 16S rRNA gene sequence analysis. These results indicate that the provision of hydrophobic sorbents containing sorbed PAHs in the enrichment procedure discriminated in favor of certain bacterial characteristics. The new isolation method is appropriate to select for adherent PAH-degrading bacteria, which might be useful to biodegrade sorbed PAHs in soils and sludge. PMID:10788347
Promoting calls to a quitline: quantifying the influence of message theme, strong negative emotions and graphic images in television advertisements.

PubMed

Farrelly, Matthew C; Davis, Kevin C; Nonnemaker, James M; Kamyab, Kian; Jackson, Christine

2011-07-01

To understand the relative effectiveness of television advertisements that differ in their thematic focus and portrayals of negative emotions and/or graphic images in promoting calls to a smokers' quitline. Regression analysis is used to explain variation in quarterly media market-level per smoker calls to the New York State Smokers' Quitline from 2001 to 2009. The primary independent variable is quarterly market-level delivery of television advertisements measured by target audience rating points (TARPs). Advertisements were characterised by their overall objective--promoting cessation, highlighting the dangers of secondhand smoke (SHS) or other--and by their portrayals of strong negative emotions and graphic images. Per smoker call volume is positively correlated with total TARPs (p<0.001), and cessation advertisements are more effective than SHS advertisements in promoting quitline call volume. Advertisements with graphic images only or neither strong negative emotions nor graphic images are associated with higher call volume with similar effect sizes. Call volume was not significantly associated with the number of TARPs for advertisements with strong negative emotions only (p=0.71) or with both graphic images and strong emotions (p=0.09). Exposure to television advertisements is strongly associated with quitline call volume, and both cessation and SHS advertisements can be effective. The use of strong negative emotions in advertisements may be effective in promoting smoking cessation in the population but does not appear to influence quitline call volume. Further research is needed to understand the role of negative emotions in promoting calls to quitlines and cessation more broadly among the majority of smokers who do not call quitlines.
Promising intervention strategies to reduce parents' use of physical punishment.

PubMed

Gershoff, Elizabeth T; Lee, Shawna J; Durrant, Joan E

2017-09-01

The strong and ever-growing evidence base demonstrating that physical punishment places children at risk for a range of negative outcomes, coupled with global recognition of children's inherent rights to protection and dignity, has led to the emergence of programs specifically designed to prevent physical punishment by parents. This paper describes promising programs and strategies designed for each of three levels of intervention - indicated, selective, and universal - and summarizes the existing evidence base of each. Areas for further program development and evaluation are identified. Copyright © 2017 Elsevier Ltd. All rights reserved.
Examining Convergence of Retrospective and Ecological Momentary Assessment Measures of Negative Affect and Eating Disorder Behaviors

PubMed Central

Wonderlich, Joseph A.; Lavender, Jason M.; Wonderlich, Stephen A.; Peterson, Carol B.; Crow, Scott J.; Engel, Scott G.; Le Grange, Daniel; Mitchell, James E.; Crosby, Ross D.

2017-01-01

Objective Data gathered via retrospective forms of assessment are subject to various recall biases. Ecological momentary assessment (EMA) is an alternative approach involving repeated momentary assessments within a participant's natural environment, thus reducing recall biases and improving ecological validity. EMA has been used in numerous prior studies examining various constructs of theoretical relevance to eating disorders. Method This investigation includes data from three previously published studies with distinct clinical samples: (a) women with anorexia nervosa (N=118), (b) women with bulimia nervosa (N=133), and (c) obese men and women (N=50; 9 with current binge eating disorder). Each study assessed negative affective states and eating disorder behaviors using traditional retrospective assessments and EMA. Spearman rho correlations were used to evaluate the concordance of retrospective versus EMA measures of affective and/or behavioral constructs in each sample. Bland-Altman plots were also used to further evaluate concordance in the assessment of eating disorder behaviors. Results There was moderate to strong concordance for the measures of negative affective states across all three studies. Moderate to strong concordance was also found for the measures of binge eating and exercise frequency. The strongest evidence of concordance across measurement approaches was found for purging behaviors. Discussion Overall, these preliminary findings support the convergence of retrospective and EMA assessments of both negative affective states and various eating disorder behaviors. Given the advantages and disadvantages associated with each of these assessment approaches, the specific questions being studied in future empirical studies should inform decisions regarding selection of the most appropriate method. PMID:25195932
Food preferences of larvae of Antarctic silverfish Pleuragramma antarcticum Boulenger, 1902 from Terre Adélie coastal waters during summer 2004

NASA Astrophysics Data System (ADS)

Vallet, Carole; Beans, Cristina; Koubbi, Philippe; Courcot, Lucie; Hecq, Jean-Henri; Goffart, Anne

2011-08-01

Ichthyoplankton samples were collected from 19 to 31 January 2004 in the Dumont d’Urville Sea (East Antarctic shelf). The Nototheniidae Pleuragramma antarcticum comprised more than 90% of the sampled larvae. Gut contents of 95 P antarcticum larvae were examined. Most larvae fed on phytoplankton, especially diatoms, whereas some other specimens had a mixed diet with phyto- and zooplankton prey. A single specimen fed exclusively on copepods. The stomach contents was dominated by three diatoms taxa, such as Thalassiothrix antarctica, Fragilariopsis spp. and Chaetoceros spp. Prey selection was apparently food density dependent, with an inverse relationship between food abundance and selection feeding. Larvae selected positively some diatoms, such as Coscinodiscus spp. and T. antarctica, presenting a low concentration in the water column compared to Fragilariopsis spp., which were strongly negatively selected. During summer, larvae were opportunistic feeders with a broad trophic niche, which allowed them to switch between different food types.
Socioemotional selectivity theory, aging, and health: the increasingly delicate balance between regulating emotions and making tough choices.

PubMed

Löckenhoff, Corinna E; Carstensen, Laura L

2004-12-01

After providing an introductory overview of socioemotional selectivity theory, we review empirical evidence for its basic postulates and consider the implications of the predicted cognitive and behavioral changes for physical health. The main assertion of socioemotional selectivity theory is that when boundaries on time are perceived, present-oriented goals related to emotional meaning are prioritized over future-oriented goals aimed at acquiring information and expanding horizons. Such motivational changes, which are strongly correlated with chronological age, systematically influence social preferences, social network composition, emotion regulation, and cognitive processing. On the one hand, there is considerable reason to believe that such changes are good for well-being and social adjustment. On the other hand, the very same motivational changes may limit health-related information-seeking and influence attention, memory, and decision-making such that positive material is favored over negative information. Grounding our arguments in socioemotional selectivity theory, we consider possible ways to tailor contexts such that disadvantages are avoided.
Nucleotide variation at the dopa decarboxylase (Ddc) gene in natural populations of Drosophila melanogaster.

PubMed

Tatarenkov, Andrey; Ayala, Francisco J

2007-08-01

We studied nucleotide sequence variation at the gene coding for dopa decarboxylase (Ddc) in seven populations of Drosophila melanogaster. Strength and pattern of linkage disequilibrium are somewhat distinct in the extensively sampled Spanish and Raleigh populations. In the Spanish population, a few sites are in strong positive association, whereas a large number of sites in the Raleigh population are associated nonrandomly but the association is not strong. Linkage disequilibrium analysis shows presence of two groups of haplotypes in the populations, each of which is fairly diverged, suggesting epistasis or inversion polymorphism. There is evidence of two forms of natural selection acting on Ddc. The McDonald-Kreitman test indicates a deficit of fixed amino acid differences between D. melanogaster and D. simulans, which may be due to negative selection. An excess of derived alleles at high frequency, significant according to the H-test, is consistent with the effect of hitchhiking. The hitchhiking may have been caused by directional selection downstream of the locus studied, as suggested by a gradual decrease of the polymorphism-to-divergence ratio. Altogether, the Ddc locus exhibits a complicated pattern of variation apparently due to several evolutionary forces. Such a complex pattern may be a result of an unusually high density of functionally important genes.
Emotional reactivity to incentive downshift as a correlated response to selection of high and low alcohol preferring mice and an influencing factor on ethanol intake.

PubMed

Matson, Liana M; Grahame, Nicholas J

2015-11-01

Losing a job or significant other are examples of incentive loss that result in negative emotional reactions. The occurrence of negative life events is associated with increased drinking (Keyes, Hatzenbuehler, & Hasin, 2011). Further, certain genotypes are more likely to drink alcohol in response to stressful negative life events (Blomeyer et al., 2008; Covault et al., 2007). Shared genetic factors may contribute to alcohol drinking and emotional reactivity, but this relationship is not currently well understood. We used an incentive downshift paradigm to address whether emotional reactivity is elevated in mice predisposed to drink alcohol. We also investigated if ethanol drinking is influenced in High Alcohol Preferring mice that had been exposed to an incentive downshift. Incentive downshift procedures have been widely utilized to model emotional reactivity, and involve shifting a high reward group to a low reward and comparing the shifted group to a consistently rewarded control group. Here, we show that replicate lines of selectively bred High Alcohol Preferring mice exhibited larger successive negative contrast effects than their corresponding replicate Low Alcohol Preferring lines, providing strong evidence for a genetic association between alcohol drinking and susceptibility to the emotional effects of negative contrast. These mice can be used to study the shared neurological and genetic underpinnings of emotional reactivity and alcohol preference. Unexpectedly, an incentive downshift suppressed ethanol drinking immediately following an incentive downshift. This could be due to a specific effect of negative contrast on ethanol consumption or a suppressive effect on consummatory behavior in general. These data suggest that either alcohol intake does not provide the anticipated negative reinforcement, or that a single test was insufficient for animals to learn to drink following incentive downshift. However, the emotional intensity following incentive downshift provides initial evidence that this type of emotional reactivity may be a predisposing factor in alcoholism. Copyright © 2015 Elsevier Inc. All rights reserved.
Update on Aire and thymic negative selection.

PubMed

Passos, Geraldo A; Speck-Hernandez, Cesar A; Assis, Amanda F; Mendes-da-Cruz, Daniella A

2018-01-01

Twenty years ago, the autoimmune regulator (Aire) gene was associated with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy, and was cloned and sequenced. Its importance goes beyond its abstract link with human autoimmune disease. Aire identification opened new perspectives to better understand the molecular basis of central tolerance and self-non-self distinction, the main properties of the immune system. Since 1997, a growing number of immunologists and molecular geneticists have made important discoveries about the function of Aire, which is essentially a pleiotropic gene. Aire is one of the functional markers in medullary thymic epithelial cells (mTECs), controlling their differentiation and expression of peripheral tissue antigens (PTAs), mTEC-thymocyte adhesion and the expression of microRNAs, among other functions. With Aire, the immunological tolerance became even more apparent from the molecular genetics point of view. Currently, mTECs represent the most unusual cells because they express almost the entire functional genome but still maintain their identity. Due to the enormous diversity of PTAs, this uncommon gene expression pattern was termed promiscuous gene expression, the interpretation of which is essentially immunological - i.e. it is related to self-representation in the thymus. Therefore, this knowledge is strongly linked to the negative selection of autoreactive thymocytes. In this update, we focus on the most relevant results of Aire as a transcriptional and post-transcriptional controller of PTAs in mTECs, its mechanism of action, and its influence on the negative selection of autoreactive thymocytes as the bases of the induction of central tolerance and prevention of autoimmune diseases. © 2017 John Wiley & Sons Ltd.
A Conserved Cytochrome P450 Evolved in Seed Plants Regulates Flower Maturation.

PubMed

Liu, Zhenhua; Boachon, Benoît; Lugan, Raphaël; Tavares, Raquel; Erhardt, Mathieu; Mutterer, Jérôme; Demais, Valérie; Pateyron, Stéphanie; Brunaud, Véronique; Ohnishi, Toshiyuki; Pencik, Ales; Achard, Patrick; Gong, Fan; Hedden, Peter; Werck-Reichhart, Danièle; Renault, Hugues

2015-12-07

Global inspection of plant genomes identifies genes maintained in low copies across taxa and under strong purifying selection, which are likely to have essential functions. Based on this rationale, we investigated the function of the low-duplicated CYP715 cytochrome P450 gene family that appeared early in seed plants and evolved under strong negative selection. Arabidopsis CYP715A1 showed a restricted tissue-specific expression in the tapetum of flower buds and in the anther filaments upon anthesis. cyp715a1 insertion lines showed a strong defect in petal development, and transient alteration of pollen intine deposition. Comparative expression analysis revealed the downregulated expression of genes involved in pollen development, cell wall biogenesis, hormone homeostasis, and floral sesquiterpene biosynthesis, especially TPS21 and several key genes regulating floral development such as MYB21, MYB24, and MYC2. Accordingly, floral sesquiterpene emission was suppressed in the cyp715a1 mutants. Flower hormone profiling, in addition, indicated a modification of gibberellin homeostasis and a strong disturbance of the turnover of jasmonic acid derivatives. Petal growth was partially restored by the active gibberellin GA3 or the functional analog of jasmonoyl-isoleucine, coronatine. CYP715 appears to function as a key regulator of flower maturation, synchronizing petal expansion and volatile emission. It is thus expected to be an important determinant of flower-insect interaction. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

Impairment of organ-specific T cell negative selection by diabetes susceptibility genes: genomic analysis by mRNA profiling.

PubMed

Liston, Adrian; Hardy, Kristine; Pittelkow, Yvonne; Wilson, Susan R; Makaroff, Lydia E; Fahrer, Aude M; Goodnow, Christopher C

2007-01-01

T cells in the thymus undergo opposing positive and negative selection processes so that the only T cells entering circulation are those bearing a T cell receptor (TCR) with a low affinity for self. The mechanism differentiating negative from positive selection is poorly understood, despite the fact that inherited defects in negative selection underlie organ-specific autoimmune disease in AIRE-deficient people and the non-obese diabetic (NOD) mouse strain Here we use homogeneous populations of T cells undergoing either positive or negative selection in vivo together with genome-wide transcription profiling on microarrays to identify the gene expression differences underlying negative selection to an Aire-dependent organ-specific antigen, including the upregulation of a genomic cluster in the cytogenetic band 2F. Analysis of defective negative selection in the autoimmune-prone NOD strain demonstrates a global impairment in the induction of the negative selection response gene set, but little difference in positive selection response genes. Combining expression differences with genetic linkage data, we identify differentially expressed candidate genes, including Bim, Bnip3, Smox, Pdrg1, Id1, Pdcd1, Ly6c, Pdia3, Trim30 and Trim12. The data provide a molecular map of the negative selection response in vivo and, by analysis of deviations from this pathway in the autoimmune susceptible NOD strain, suggest that susceptibility arises from small expression differences in genes acting at multiple points in the pathway between the TCR and cell death.
Impairment of organ-specific T cell negative selection by diabetes susceptibility genes: genomic analysis by mRNA profiling

PubMed Central

Liston, Adrian; Hardy, Kristine; Pittelkow, Yvonne; Wilson, Susan R; Makaroff, Lydia E; Fahrer, Aude M; Goodnow, Christopher C

2007-01-01

Background T cells in the thymus undergo opposing positive and negative selection processes so that the only T cells entering circulation are those bearing a T cell receptor (TCR) with a low affinity for self. The mechanism differentiating negative from positive selection is poorly understood, despite the fact that inherited defects in negative selection underlie organ-specific autoimmune disease in AIRE-deficient people and the non-obese diabetic (NOD) mouse strain Results Here we use homogeneous populations of T cells undergoing either positive or negative selection in vivo together with genome-wide transcription profiling on microarrays to identify the gene expression differences underlying negative selection to an Aire-dependent organ-specific antigen, including the upregulation of a genomic cluster in the cytogenetic band 2F. Analysis of defective negative selection in the autoimmune-prone NOD strain demonstrates a global impairment in the induction of the negative selection response gene set, but little difference in positive selection response genes. Combining expression differences with genetic linkage data, we identify differentially expressed candidate genes, including Bim, Bnip3, Smox, Pdrg1, Id1, Pdcd1, Ly6c, Pdia3, Trim30 and Trim12. Conclusion The data provide a molecular map of the negative selection response in vivo and, by analysis of deviations from this pathway in the autoimmune susceptible NOD strain, suggest that susceptibility arises from small expression differences in genes acting at multiple points in the pathway between the TCR and cell death. PMID:17239257
The Ecology and Evolution of Cancer: The Ultra-Microevolutionary Process.

PubMed

Wu, Chung-I; Wang, Hurng-Yi; Ling, Shaoping; Lu, Xuemei

2016-11-23

Although tumorigenesis has been accepted as an evolutionary process ( 20 , 102 ), many forces may operate differently in cancers than in organisms, as they evolve at vastly different time scales. Among such forces, natural selection, here defined as differential cellular proliferation among distinct somatic cell genotypes, is particularly interesting because its action might be thwarted in multicellular organisms ( 20 , 29 ). In this review, selection is analyzed in two stages of cancer evolution: Stage I is the evolution between tumors and normal tissues, and Stage II is the evolution within tumors. The Cancer Genome Atlas (TCGA) data show a low degree of convergent evolution in Stage I, where genetic changes are not extensively shared among cases. An equally important, albeit much less highlighted, discovery using TCGA data is that there is almost no net selection in cancer evolution. Both positive and negative selection are evident but they neatly cancel each other out, rendering total selection ineffective in the absence of recombination. The efficacy of selection is even lower in Stage II, where neutral (non-Darwinian) evolution is increasingly supported by high-density sampling studies ( 81 , 123 ). Because natural selection is not a strong deterministic force, cancers usually evolve divergently even in similar tissue environments.
On The Relationship between Suspended Solids of Different Size, the Observed Boundary Flux and Rejection Values for Membranes Treating a Civil Wastewater Stream.

PubMed

Stoller, Marco; Pulido, Javier Miguel Ochando; Palma, Luca Di

2014-08-04

Membrane fouling is one of the main issues in membrane processes, leading to a progressive decrease of permeability. High fouling rates strongly reduce the productivity of the membrane plant, and negatively affect the surviving rate of the membrane modules, especially when real wastewater is treated. On the other hand, since selectivity must meet certain target requirements, fouling may lead to unexpected selectivity improvements due to the formation of an additional superficial layer formed of foulants and that act like a selective secondary membrane layer. In this case, a certain amount of fouling may be profitable to the point where selectivity targets were reached and productivity is not significantly affected. In this work, the secondary clarifier of a step sludge recirculation bioreactor treating municipal wastewater was replaced by a membrane unit, aiming at recovering return sludge and producing purified water. Fouling issues of such a system were checked by boundary flux measurements. A simple model for the description of the observed productivity and selectivity values as a function of membrane fouling is proposed.
On The Relationship between Suspended Solids of Different Size, the Observed Boundary Flux and Rejection Values for Membranes Treating a Civil Wastewater Stream

PubMed Central

Stoller, Marco; Pulido, Javier Miguel Ochando; Di Palma, Luca

2014-01-01

Membrane fouling is one of the main issues in membrane processes, leading to a progressive decrease of permeability. High fouling rates strongly reduce the productivity of the membrane plant, and negatively affect the surviving rate of the membrane modules, especially when real wastewater is treated. On the other hand, since selectivity must meet certain target requirements, fouling may lead to unexpected selectivity improvements due to the formation of an additional superficial layer formed of foulants and that act like a selective secondary membrane layer. In this case, a certain amount of fouling may be profitable to the point where selectivity targets were reached and productivity is not significantly affected. In this work, the secondary clarifier of a step sludge recirculation bioreactor treating municipal wastewater was replaced by a membrane unit, aiming at recovering return sludge and producing purified water. Fouling issues of such a system were checked by boundary flux measurements. A simple model for the description of the observed productivity and selectivity values as a function of membrane fouling is proposed. PMID:25093867
Selective scanning tunnelling microscope electron-induced reactions of single biphenyl molecules on a Si(100) surface.

PubMed

Riedel, Damien; Bocquet, Marie-Laure; Lesnard, Hervé; Lastapis, Mathieu; Lorente, Nicolas; Sonnet, Philippe; Dujardin, Gérald

2009-06-03

Selective electron-induced reactions of individual biphenyl molecules adsorbed in their weakly chemisorbed configuration on a Si(100) surface are investigated by using the tip of a low-temperature (5 K) scanning tunnelling microscope (STM) as an atomic size source of electrons. Selected types of molecular reactions are produced, depending on the polarity of the surface voltage during STM excitation. At negative surface voltages, the biphenyl molecule diffuses across the surface in its weakly chemisorbed configuration. At positive surface voltages, different types of molecular reactions are activated, which involve the change of adsorption configuration from the weakly chemisorbed to the strongly chemisorbed bistable and quadristable configurations. Calculated reaction pathways of the molecular reactions on the silicon surface, using the nudge elastic band method, provide evidence that the observed selectivity as a function of the surface voltage polarity cannot be ascribed to different activation energies. These results, together with the measured threshold surface voltages and the calculated molecular electronic structures via density functional theory, suggest that the electron-induced molecular reactions are driven by selective electron detachment (oxidation) or attachment (reduction) processes.
Dengue virus type 1 clade replacement in recurring homotypic outbreaks

PubMed Central

2013-01-01

Background Recurring dengue outbreaks occur in cyclical pattern in most endemic countries. The recurrences of dengue virus (DENV) infection predispose the population to increased risk of contracting the severe forms of dengue. Understanding the DENV evolutionary mechanism underlying the recurring dengue outbreaks has important implications for epidemic prediction and disease control. Results We used a set of viral envelope (E) gene to reconstruct the phylogeny of DENV-1 isolated between the periods of 1987–2011 in Malaysia. Phylogenetic analysis of DENV-1 E gene revealed that genotype I virus clade replacements were associated with the cyclical pattern of major DENV-1 outbreaks in Malaysia. A total of 9 non-conservative amino acid substitutions in the DENV-1 E gene consensus were identified; 4 in domain I, 3 in domain II and 2 in domain III. Selection pressure analyses did not reveal any positively selected codon site within the full length E gene sequences (1485 nt, 495 codons). A total of 183 (mean dN/dS = 0.0413) negatively selected sites were found within the Malaysian isolates; neither positive nor negative selection was noted for the remaining 312 codons. All the viruses were cross-neutralized by the respective patient sera suggesting no strong support for immunological advantage of any of the amino acid substitutions. Conclusion DENV-1 clade replacement is associated with recurrences of major DENV-1 outbreaks in Malaysia. Our findings are consistent with those of other studies that the DENV-1 clade replacement is a stochastic event independent of positive selection. PMID:24073945
Screening Allelochemical-Resistant Species of the Alien Invasive Mikania micrantha for Restoration in South China

PubMed Central

Wu, Ai-Ping; Li, Zi-Li; He, Fei-Fei; Wang, Yan-Hong; Dong, Ming

2015-01-01

To screen allelochemical-resistant species of the alien invasive weed Mikania micrantha, we studied the allelopathic inhibition effects of the leaf aqueous extract (LAE) of Mikania on seed germination and seedling growth of the 26 species native or naturalized in the invaded region in South China. Seed germination was more strongly negatively affected by LAE than seedling growth. Responses of seed germination and seed growth to LAE differed differently among the target species. LAE more strongly negatively affected seed germination, but less strongly negatively affected seedling growth, in non-legume species than in legume species. LAE more strongly negatively affected seed germination and seedling growth in native species than naturalized exotic species. Therefore, naturalized exotic non-legume seedlings are more suitable than seeds of native legume species for restoration of Mikania-invaded habitats. PMID:26177031
Screening Allelochemical-Resistant Species of the Alien Invasive Mikania micrantha for Restoration in South China.

PubMed

Wu, Ai-Ping; Li, Zi-Li; He, Fei-Fei; Wang, Yan-Hong; Dong, Ming

2015-01-01

To screen allelochemical-resistant species of the alien invasive weed Mikania micrantha, we studied the allelopathic inhibition effects of the leaf aqueous extract (LAE) of Mikania on seed germination and seedling growth of the 26 species native or naturalized in the invaded region in South China. Seed germination was more strongly negatively affected by LAE than seedling growth. Responses of seed germination and seed growth to LAE differed differently among the target species. LAE more strongly negatively affected seed germination, but less strongly negatively affected seedling growth, in non-legume species than in legume species. LAE more strongly negatively affected seed germination and seedling growth in native species than naturalized exotic species. Therefore, naturalized exotic non-legume seedlings are more suitable than seeds of native legume species for restoration of Mikania-invaded habitats.
Studies of the TLR4-associated protein MD-2 using yeast-display and mutational analyses

PubMed Central

Mattis, Daiva M.; Chervin, Adam; Ranoa, Diana; Kelley, Stacy; Tapping, Richard; Kranz, David M.

2015-01-01

Bacterial lipopolysaccharide (LPS) activates the innate immune system by forming a complex with myeloid differentiation factor 2 (MD-2) and Toll-like receptor 4 (TLR4), which is present on antigen presenting cells. MD-2 plays an essential role in this activation of the innate immune system as a member of the ternary complex, TLR4:MD-2:LPS. With the goal of further understanding the molecular details of the interaction of MD-2 with LPS and TLR4, and possibly toward engineering dominant negative regulators of the MD-2 protein, here we subjected MD-2 to a mutational analysis using yeast display. The approach included generation of site-directed alanine mutants, and ligand-driven selections of MD-2 mutant libraries. Our findings showed that: 1) proline mutations in the F119-K132 loop that binds LPS were strongly selected for enhanced yeast surface stability, 2) there was a preference for positive-charged side chains (R/K) at residue 120 for LPS binding, and negative-charged side chains (D/E) for TLR4 binding, 3) aromatic residues were strongly preferred at F119 and F121 for LPS binding, and 4) an MD-2 mutant (T84N/D101A/S118A/S120D/K122P) exhibited increased binding to TLR4 but decreased binding to LPS. These studies revealed the impact of specific residues and regions of MD-2 on the binding of LPS and TLR4, and they provide a framework for further directed evolution of the MD-2 protein. PMID:26320630
Conditional entropy in variation-adjusted windows detects selection signatures associated with expression quantitative trait loci (eQTLs)

PubMed Central

2015-01-01

Background Over the past 50,000 years, shifts in human-environmental or human-human interactions shaped genetic differences within and among human populations, including variants under positive selection. Shaped by environmental factors, such variants influence the genetics of modern health, disease, and treatment outcome. Because evolutionary processes tend to act on gene regulation, we test whether regulatory variants are under positive selection. We introduce a new approach to enhance detection of genetic markers undergoing positive selection, using conditional entropy to capture recent local selection signals. Results We use conditional logistic regression to compare our Adjusted Haplotype Conditional Entropy (H|H) measure of positive selection to existing positive selection measures. H|H and existing measures were applied to published regulatory variants acting in cis (cis-eQTLs), with conditional logistic regression testing whether regulatory variants undergo stronger positive selection than the surrounding gene. These cis-eQTLs were drawn from six independent studies of genotype and RNA expression. The conditional logistic regression shows that, overall, H|H is substantially more powerful than existing positive-selection methods in identifying cis-eQTLs against other Single Nucleotide Polymorphisms (SNPs) in the same genes. When broken down by Gene Ontology, H|H predictions are particularly strong in some biological process categories, where regulatory variants are under strong positive selection compared to the bulk of the gene, distinct from those GO categories under overall positive selection. . However, cis-eQTLs in a second group of genes lack positive selection signatures detectable by H|H, consistent with ancient short haplotypes compared to the surrounding gene (for example, in innate immunity GO:0042742); under such other modes of selection, H|H would not be expected to be a strong predictor.. These conditional logistic regression models are adjusted for Minor allele frequency(MAF); otherwise, ascertainment bias is a huge factor in all eQTL data sets. Relationships between Gene Ontology categories, positive selection and eQTL specificity were replicated with H|H in a single larger data set. Our measure, Adjusted Haplotype Conditional Entropy (H|H), was essential in generating all of the results above because it: 1) is a stronger overall predictor for eQTLs than comparable existing approaches, and 2) shows low sequential auto-correlation, overcoming problems with convergence of these conditional regression statistical models. Conclusions Our new method, H|H, provides a consistently more robust signal associated with cis-eQTLs compared to existing methods. We interpret this to indicate that some cis-eQTLs are under positive selection compared to their surrounding genes. Conditional entropy indicative of a selective sweep is an especially strong predictor of eQTLs for genes in several biological processes of medical interest. Where conditional entropy is a weak or negative predictor of eQTLs, such as innate immune genes, this would be consistent with balancing selection acting on such eQTLs over long time periods. Different measures of selection may be needed for variant prioritization under other modes of evolutionary selection. PMID:26111110
Selection signatures in four lignin genes from switchgrass populations divergently selected for in vitro dry matter digestibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Shiyu; Kaeppler, Shawn M.; Vogel, Kenneth P.

Switchgrass is undergoing development as a dedicated cellulosic bioenergy crop. Fermentation of lignocellulosic biomass to ethanol in a bioenergy system or to volatile fatty acids in a livestock production system is strongly and negatively influenced by lignification of cell walls. This study detects specific loci that exhibit selection signatures across switchgrass breeding populations that differ in in vitro dry matter digestibility (IVDMD), ethanol yield, and lignin concentration. Allele frequency changes in candidate genes were used to detect loci under selection. Out of the 183 polymorphisms identified in the four candidate genes, twenty-five loci in the intron regions and four locimore » in coding regions were found to display a selection signature. All loci in the coding regions are synonymous substitutions. Selection in both directions were observed on polymorphisms that appeared to be under selection. Genetic diversity and linkage disequilibrium within the candidate genes were low. The recurrent divergent selection caused excessive moderate allele frequencies in the cycle 3 reduced lignin population as compared to the base population. As a result, this study provides valuable insight on genetic changes occurring in short-term selection in the polyploid populations, and discovered potential markers for breeding switchgrass with improved biomass quality.« less
Selection signatures in four lignin genes from switchgrass populations divergently selected for in vitro dry matter digestibility

DOE PAGES

Chen, Shiyu; Kaeppler, Shawn M.; Vogel, Kenneth P.; ...

2016-11-28

Switchgrass is undergoing development as a dedicated cellulosic bioenergy crop. Fermentation of lignocellulosic biomass to ethanol in a bioenergy system or to volatile fatty acids in a livestock production system is strongly and negatively influenced by lignification of cell walls. This study detects specific loci that exhibit selection signatures across switchgrass breeding populations that differ in in vitro dry matter digestibility (IVDMD), ethanol yield, and lignin concentration. Allele frequency changes in candidate genes were used to detect loci under selection. Out of the 183 polymorphisms identified in the four candidate genes, twenty-five loci in the intron regions and four locimore » in coding regions were found to display a selection signature. All loci in the coding regions are synonymous substitutions. Selection in both directions were observed on polymorphisms that appeared to be under selection. Genetic diversity and linkage disequilibrium within the candidate genes were low. The recurrent divergent selection caused excessive moderate allele frequencies in the cycle 3 reduced lignin population as compared to the base population. As a result, this study provides valuable insight on genetic changes occurring in short-term selection in the polyploid populations, and discovered potential markers for breeding switchgrass with improved biomass quality.« less
Argininosuccinate synthetase (ASS) deficiency in high-grade pulmonary neuroendocrine carcinoma: an opportunity for personalized targeted therapy.

PubMed

Walts, Ann E; Bomalaski, John S; Ines, Delma; Orsulic, Sandra

2015-08-01

Cells deficient in argininosuccinate synthetase (ASS) must absorb the arginine they need for growth from circulating blood. Treatment with pegylated arginine deiminase (ADI-PEG 20) selectively eliminates arginine from the circulation and has shown some efficacy against ASS-deficient tumors including small cell lung cancer (SCLC). We sought to assess ASS expression in a cohort of high-grade pulmonary neuroendocrine carcinomas (PNEC) which include SCLC and large cell neuroendocrine carcinoma (LCNEC). Sixty-nine PNEC (49 SCLC and 20 LCNEC) were retrieved from our pathology archives. Formalin-fixed paraffin-embedded sections of the 54 primary tumors, 15 metastases and appropriate positive and negative controls were immunostained using an ASS-specific monoclonal antibody. Positive staining in <30 % of the tumor was scored as weak; staining in ≥30 % of the tumor was scored as strong. The absence of staining in the tumor was recorded as ASS negative. 58 % of the PNEC including 61.2 % of the SCLC and 50 % of the LCNEC were ASS negative. These ASS-negative tumors included 63 % of the primary and 40 % of the metastatic lesions tested. More than 50 % of the high-grade PNEC tested lack immunohistochemically detectable ASS, suggesting that they are auxotrophic for arginine and potential candidates for arginine deprivation therapy. PNEC comprise about 25 % of primary lung cancers and have a 5-year overall survival of only 5-10 %, underscoring the need for new and more effective therapies. Immunostaining for ASS has potential to improve the selection of patients with PNEC for arginine deprivation therapy with ADI-PEG 20.
Natural selection and inheritance of breeding time and clutch size in the collared flycatcher.

PubMed

Sheldon, B C; Kruuk, L E B; Merilä, J

2003-02-01

Many characteristics of organisms in free-living populations appear to be under directional selection, possess additive genetic variance, and yet show no evolutionary response to selection. Avian breeding time and clutch size are often-cited examples of such characters. We report analyses of inheritance of, and selection on, these traits in a long-term study of a wild population of the collared flycatcher Ficedula albicollis. We used mixed model analysis with REML estimation ("animal models") to make full use of the information in complex multigenerational pedigrees. Heritability of laying date, but not clutch size, was lower than that estimated previously using parent-offspring regressions, although for both traits there was evidence of substantial additive genetic variance (h2 = 0.19 and 0.29, respectively). Laying date and clutch size were negatively genetically correlated (rA = -0.41 +/- 0.09), implying that selection on one of the traits would cause a correlated response in the other, but there was little evidence to suggest that evolution of either trait would be constrained by correlations with other phenotypic characters. Analysis of selection on these traits in females revealed consistent strong directional fecundity selection for earlier breeding at the level of the phenotype (beta = -0.28 +/- 0.03), but little evidence for stabilising selection on breeding time. We found no evidence that clutch size was independently under selection. Analysis of fecundity selection on breeding values for laying date, estimated from an animal model, indicated that selection acts directly on additive genetic variance underlying breeding time (beta = -0.20 +/- 0.04), but not on clutch size (beta = 0.03 +/- 0.05). In contrast, selection on laying date via adult female survival fluctuated in sign between years, and was opposite in sign for selection on phenotypes (negative) and breeding values (positive). Our data thus suggest that any evolutionary response to selection on laying date is partially constrained by underlying life-history trade-offs, and illustrate the difficulties in using purely phenotypic measures and incomplete fitness estimates to assess evolution of life-history trade-offs. We discuss some of the difficulties associated with understanding the evolution of laying date and clutch size in natural populations.
Mutation Supply and Relative Fitness Shape the Genotypes of Ciprofloxacin-Resistant Escherichia coli.

PubMed

Huseby, Douglas L; Pietsch, Franziska; Brandis, Gerrit; Garoff, Linnéa; Tegehall, Angelica; Hughes, Diarmaid

2017-05-01

Ciprofloxacin is an important antibacterial drug targeting Type II topoisomerases, highly active against Gram-negatives including Escherichia coli. The evolution of resistance to ciprofloxacin in E. coli always requires multiple genetic changes, usually including mutations affecting two different drug target genes, gyrA and parC. Resistant mutants selected in vitro or in vivo can have many different mutations in target genes and efflux regulator genes that contribute to resistance. Among resistant clinical isolates the genotype, gyrA S83L D87N, parC S80I is significantly overrepresented suggesting that it has a selective advantage. However, the evolutionary or functional significance of this high frequency resistance genotype is not fully understood. By combining experimental data and mathematical modeling, we addressed the reasons for the predominance of this specific genotype. The experimental data were used to model trajectories of mutational resistance evolution under different conditions of drug exposure and population bottlenecks. We identified the order in which specific mutations are selected in the clinical genotype, showed that the high frequency genotype could be selected over a range of drug selective pressures, and was strongly influenced by the relative fitness of alternative mutations and factors affecting mutation supply. Our data map for the first time the fitness landscape that constrains the evolutionary trajectories taken during the development of clinical resistance to ciprofloxacin and explain the predominance of the most frequently selected genotype. This study provides strong support for the use of in vitro competition assays as a tool to trace evolutionary trajectories, not only in the antibiotic resistance field. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
Specialized proteasome subunits play an essential role in thymic selection of CD8+ T cells

PubMed Central

Kincaid, Eleanor Z.; Murata, Shigeo; Tanaka, Keiji; Rock, Kenneth L.

2016-01-01

The cells that stimulate positive selection express different specialized proteasome β-subunits than all other cells, including those involved in negative selection. Mice that lack all four specialized proteasome β-subunits, and therefore express only constitutive proteasomes in all cells, had a profound defect in the generation of CD8+ T cells. While a defect in positive selection would reflect an inability to generate the appropriate positively selecting peptides, a block at negative selection would point to the potential need to switch peptides between positive and negative selection to avoid the two processes often cancelling each other out. We found that the block in T cell development occurred around the checkpoints of positive and, surprisingly, also negative selection. PMID:27294792
Energetic benefits and adaptations in mammalian limbs: Scale effects and selective pressures.

PubMed

Kilbourne, Brandon M; Hoffman, Louwrens C

2015-06-01

Differences in limb size and shape are fundamental to mammalian morphological diversity; however, their relevance to locomotor costs has long been subject to debate. In particular, it remains unknown if scale effects in whole limb morphology could partially underlie decreasing mass-specific locomotor costs with increasing limb length. Whole fore- and hindlimb inertial properties reflecting limb size and shape-moment of inertia (MOI), mass, mass distribution, and natural frequency-were regressed against limb length for 44 species of quadrupedal mammals. Limb mass, MOI, and center of mass position are negatively allometric, having a strong potential for lowering mass-specific locomotor costs in large terrestrial mammals. Negative allometry of limb MOI results in a 40% reduction in MOI relative to isometry's prediction for our largest sampled taxa. However, fitting regression residuals to adaptive diversification models reveals that codiversification of limb mass, limb length, and body mass likely results from selection for differing locomotor modes of running, climbing, digging, and swimming. The observed allometric scaling does not result from selection for energetically beneficial whole limb morphology with increasing size. Instead, our data suggest that it is a consequence of differing morphological adaptations and body size distributions among quadrupedal mammals, highlighting the role of differing limb functions in mammalian evolution. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.
Effects of cytosine methylation on transcription factor binding sites

PubMed Central

2014-01-01

Background DNA methylation in promoters is closely linked to downstream gene repression. However, whether DNA methylation is a cause or a consequence of gene repression remains an open question. If it is a cause, then DNA methylation may affect the affinity of transcription factors (TFs) for their binding sites (TFBSs). If it is a consequence, then gene repression caused by chromatin modification may be stabilized by DNA methylation. Until now, these two possibilities have been supported only by non-systematic evidence and they have not been tested on a wide range of TFs. An average promoter methylation is usually used in studies, whereas recent results suggested that methylation of individual cytosines can also be important. Results We found that the methylation profiles of 16.6% of cytosines and the expression profiles of neighboring transcriptional start sites (TSSs) were significantly negatively correlated. We called the CpGs corresponding to such cytosines “traffic lights”. We observed a strong selection against CpG “traffic lights” within TFBSs. The negative selection was stronger for transcriptional repressors as compared with transcriptional activators or multifunctional TFs as well as for core TFBS positions as compared with flanking TFBS positions. Conclusions Our results indicate that direct and selective methylation of certain TFBS that prevents TF binding is restricted to special cases and cannot be considered as a general regulatory mechanism of transcription. PMID:24669864
Detecting Selection on Protein Stability through Statistical Mechanical Models of Folding and Evolution

PubMed Central

Bastolla, Ugo

2014-01-01

The properties of biomolecules depend both on physics and on the evolutionary process that formed them. These two points of view produce a powerful synergism. Physics sets the stage and the constraints that molecular evolution has to obey, and evolutionary theory helps in rationalizing the physical properties of biomolecules, including protein folding thermodynamics. To complete the parallelism, protein thermodynamics is founded on the statistical mechanics in the space of protein structures, and molecular evolution can be viewed as statistical mechanics in the space of protein sequences. In this review, we will integrate both points of view, applying them to detecting selection on the stability of the folded state of proteins. We will start discussing positive design, which strengthens the stability of the folded against the unfolded state of proteins. Positive design justifies why statistical potentials for protein folding can be obtained from the frequencies of structural motifs. Stability against unfolding is easier to achieve for longer proteins. On the contrary, negative design, which consists in destabilizing frequently formed misfolded conformations, is more difficult to achieve for longer proteins. The folding rate can be enhanced by strengthening short-range native interactions, but this requirement contrasts with negative design, and evolution has to trade-off between them. Finally, selection can accelerate functional movements by favoring low frequency normal modes of the dynamics of the native state that strongly correlate with the functional conformation change. PMID:24970217

Effects of wind energy development on nesting ecology of greater prairie-chickens in fragmented grasslands.

PubMed

McNew, Lance B; Hunt, Lyla M; Gregory, Andrew J; Wisely, Samantha M; Sandercock, Brett K

2014-08-01

Wind energy is targeted to meet 20% of U.S. energy needs by 2030, but new sites for development of renewable energy may overlap with important habitats of declining populations of grassland birds. Greater Prairie-Chickens (Tympanuchus cupido) are an obligate grassland bird species predicted to respond negatively to energy development. We used a modified before-after control-impact design to test for impacts of a wind energy development on the reproductive ecology of prairie-chickens in a 5-year study. We located 59 and 185 nests before and after development, respectively, of a 201 MW wind energy facility in Greater Prairie-Chicken nesting habitat and assessed nest site selection and nest survival relative to proximity to wind energy infrastructure and habitat conditions. Proximity to turbines did not negatively affect nest site selection (β = 0.03, 95% CI = -1.2-1.3) or nest survival (β = -0.3, 95% CI = -0.6-0.1). Instead, nest site selection and survival were strongly related to vegetative cover and other local conditions determined by management for cattle production. Integration of our project results with previous reports of behavioral avoidance of oil and gas facilities by other species of prairie grouse suggests new avenues for research to mitigate impacts of energy development. © 2014 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.
Control of Ion Selectivity in LeuT: Two Na+ Binding Sites with two different mechanisms

PubMed Central

Noskov, Sergei Y.; Roux, Benoît

2016-01-01

The x-ray structure of LeuT, a bacterial homologue of Na+/Cl−-dependent neurotransmitter transporter, provides a great opportunity to better understand the molecular basis of monovalent cation selectivity in ion-coupled transporters. LeuT possesses two ion-binding sites, NA1 and NA2, which are highly selective for Na+. Extensive all-atom free energy molecular dynamics simulations of LeuT embedded in an explicit membrane are performed at different temperatures and various occupancy states of the binding sites to dissect the molecular mechanism of ion selectivity. The results show that the two binding sites display robust selectivity for Na+ over K+ or Li+, the competing ions of most similar radii. Of particular interest, the mechanism primarily responsible for selectivity for each of the two binding sites appears to be different. In site NA1, selectivity for Na+ over K+ arises predominantly from the strong electrostatic field arising from the negatively charged carboxylate group of the leucine substrate coordinating the ion directly. In site NA2, which comprises only neutral ligands, selectivity for Na+ is enforced by the local structural restraints arising from the hydrogen-bonding network and the covalent connectivity of the poly-peptide chain surrounding the ion according to a snug-fit mechanism. PMID:18280500
CSC-3436 switched tamoxifen-induced autophagy to apoptosis through the inhibition of AMPK/mTOR pathway.

PubMed

Wu, Sheng-Tang; Sun, Guang-Huan; Cha, Tai-Lung; Kao, Chien-Chang; Chang, Sun-Yran; Kuo, Sheng-Chu; Way, Tzong-Der

2016-08-15

Triple-negative breast cancer (TNBC) lacks specific therapeutic target and limits to chemotherapy and is essential to develop novel therapeutic regimens. Increasing studies indicated that tamoxifen, a selective estrogen receptor modulators (SERMs), has anti-tumor therapeutic effect in estrogen receptor α (ERα)-negative tumor. Here, we determined whether autophagy was activated by tamoxifen in TNBC cells. Moreover, CSC-3436 displayed strong and selective growth inhibition on cancer cells. Next, we investigated the anti-proliferation effect of combination of CSC-3436 plus tamoxifen on cell death in TNBC cells. Our study found that tamoxifen induces autophagy in TNBC cells. Endoplasmic reticulum stress and AMPK/mTOR contributed tamoxifen-induced autophagy. Interestingly, in combination treatment with CSC-3436 enhanced the anti-proliferative effect of tamoxifen. We found that CSC-3436 switched tamoxifen-induced autophagy to apoptosis via cleavage of ATG-5. Moreover, AMPK/mTOR pathway may involve in CSC-3436 switched tamoxifen-induced autophagy to apoptosis. The combination of tamoxifen and CSC-3436 produced stronger tumor growth inhibition compared with CSC-3436 or tamoxifen alone treatments in vivo. These data indicated that CSC-3436 combined with tamoxifen may be a potential approach for treatment TNBC.
Condition-dependent reproductive effort in frogs infected by a widespread pathogen

PubMed Central

Roznik, Elizabeth A.; Sapsford, Sarah J.; Pike, David A.; Schwarzkopf, Lin; Alford, Ross A.

2015-01-01

To minimize the negative effects of an infection on fitness, hosts can respond adaptively by altering their reproductive effort or by adjusting their timing of reproduction. We studied effects of the pathogenic fungus Batrachochytrium dendrobatidis on the probability of calling in a stream-breeding rainforest frog (Litoria rheocola). In uninfected frogs, calling probability was relatively constant across seasons and body conditions, but in infected frogs, calling probability differed among seasons (lowest in winter, highest in summer) and was strongly and positively related to body condition. Infected frogs in poor condition were up to 40% less likely to call than uninfected frogs, whereas infected frogs in good condition were up to 30% more likely to call than uninfected frogs. Our results suggest that frogs employed a pre-existing, plastic, life-history strategy in response to infection, which may have complex evolutionary implications. If infected males in good condition reproduce at rates equal to or greater than those of uninfected males, selection on factors affecting disease susceptibility may be minimal. However, because reproductive effort in infected males is positively related to body condition, there may be selection on mechanisms that limit the negative effects of infections on hosts. PMID:26063847
Formation of stable inverse sheath in ion–ion plasma by strong negative ion emission

NASA Astrophysics Data System (ADS)

Zhang, Zhe; Wu, Bang; Yang, Shali; Zhang, Ya; Chen, Dezhi; Fan, Mingwu; Jiang, Wei

2018-06-01

The effect of strong charged particle emission on plasma–wall interactions is a classical, yet unresolved question in plasma physics. Previous studies on secondary electron emission have shown that with different emission coefficients, there are classical, space-charge-limited, and inverse sheaths. In this letter, we demonstrate that a stable ion–ion inverse sheath and ion–ion plasma are formed with strong surface emission of negative ions. The continuous space-charge-limited to inverse ion–ion sheath transition is observed, and the plasma near the surface consequently transforms into pure ion–ion plasma. The results may explain the long-puzzled experimental observation that the density of negative ions depends on only charge not mass in negative ion sources.
Task versus relationship conflict, team performance, and team member satisfaction: a meta-analysis.

PubMed

De Dreu, Carsten K W; Weingart, Laurie R

2003-08-01

This study provides a meta-analysis of research on the associations between relationship conflict, task conflict, team performance, and team member satisfaction. Consistent with past theorizing, results revealed strong and negative correlations between relationship conflict, team performance, and team member satisfaction. In contrast to what has been suggested in both academic research and introductory textbooks, however, results also revealed strong and negative (instead of the predicted positive) correlations between task conflict team performance, and team member satisfaction. As predicted, conflict had stronger negative relations with team performance in highly complex (decision making, project, mixed) than in less complex (production) tasks. Finally, task conflict was less negatively related to team performance when task conflict and relationship conflict were weakly, rather than strongly, correlated.
Unmatched U.S. Allopathic Seniors in the 2015 Main Residency Match: A Study of Applicant Behavior, Interview Selection, and Match Outcome.

PubMed

Liang, Mei; Curtin, Laurie S; Signer, Mona M; Savoia, Maria C

2017-07-01

The application and interview behaviors of unmatched U.S. allopathic medical school senior students (U.S. seniors) participating in the 2015 National Resident Matching Program (NRMP) Main Residency Match were studied in conjunction with their United States Medical Licensing Examination (USMLE) Step 1 scores and ranking preferences to understand their effects on Match outcome. USMLE Step 1 score and preferred specialty information were reviewed for U.S. seniors who responded to the 2015 NRMP Applicant Survey. Unmatched U.S. seniors were categorized as "strong," "solid," "marginal," or "weak" based on the perceived competitiveness of their Step 1 scores compared with U.S. seniors who matched in the same preferred specialty. The numbers of applications sent, interviews obtained, and programs ranked also were examined by Match outcome. Strong unmatched U.S. seniors submitted significantly more applications to achieve and attend approximately the same number of interviews as strong matched U.S. seniors. Strong unmatched seniors ranked fewer programs than their matched counterparts. As a group, unmatched U.S. seniors were less likely than their matched counterparts to rank a mix of competitive and less competitive programs and more likely to rank programs based on their perceived likelihood of matching. A small number of unmatched U.S. seniors would have matched if they had ranked programs that ranked them. U.S. seniors' Match outcomes may be affected by applicant characteristics that negatively influence their selection for interviews, and their difficulties may be exacerbated by disadvantageous ranking behaviors.
Negativity and strong monogamy of multiparty quantum entanglement beyond qubits

NASA Astrophysics Data System (ADS)

Choi, Jin Hyuk; Kim, Jeong San

2015-10-01

We propose the square of convex-roof extended negativity (SCREN) as a powerful candidate to characterize strong monogamy of multiparty quantum entanglement. We first provide a strong monogamy inequality of multiparty entanglement using SCREN and show that the tangle-based multiqubit strong-monogamy inequality can be rephrased by SCREN. We further show that the SCREN strong-monogamy inequality is still true for the counterexamples that violate tangle-based the strong-monogamy inequality in higher-dimensional quantum systems other than qubits. We also analytically show that SCREN strong-monogamy inequality is true for a large class of multiqudit states, a superposition of multiqudit generalized W -class states and vacuums. Thus SCREN is a good alternative to characterize the strong monogamy of entanglement even in multiqudit systems.
Discrimination of selected species of pathogenic bacteria using near-infrared Raman spectroscopy and principal components analysis

NASA Astrophysics Data System (ADS)

de Siqueira e Oliveira, Fernanda S.; Giana, Hector E.; Silveira, Landulfo, Jr.

2012-03-01

It has been proposed a method based on Raman spectroscopy for identification of different microorganisms involved in bacterial urinary tract infections. Spectra were collected from different bacterial colonies (Gram negative: E. coli, K. pneumoniae, P. mirabilis, P. aeruginosa, E. cloacae and Gram positive: S. aureus and Enterococcus sp.), grown in culture medium (Agar), using a Raman spectrometer with a fiber Raman probe (830 nm). Colonies were scraped from Agar surface placed in an aluminum foil for Raman measurements. After pre-processing, spectra were submitted to a Principal Component Analysis and Mahalanobis distance (PCA/MD) discrimination algorithm. It has been found that the mean Raman spectra of different bacterial species show similar bands, being the S. aureus well characterized by strong bands related to carotenoids. PCA/MD could discriminate Gram positive bacteria with sensitivity and specificity of 100% and Gram negative bacteria with good sensitivity and high specificity.
Stereotype Threat and College Academic Performance: A Latent Variables Approach*

PubMed Central

Owens, Jayanti; Massey, Douglas S.

2013-01-01

Stereotype threat theory has gained experimental and survey-based support in helping explain the academic underperformance of minority students at selective colleges and universities. Stereotype threat theory states that minority students underperform because of pressures created by negative stereotypes about their racial group. Past survey-based studies, however, are characterized by methodological inefficiencies and potential biases: key theoretical constructs have only been measured using summed indicators and predicted relationships modeled using ordinary least squares. Using the National Longitudinal Survey of Freshman, this study overcomes previous methodological shortcomings by developing a latent construct model of stereotype threat. Theoretical constructs and equations are estimated simultaneously from multiple indicators, yielding a more reliable, valid, and parsimonious test of key propositions. Findings additionally support the view that social stigma can indeed have strong negative effects on the academic performance of pejoratively stereotyped racial-minority group members, not only in laboratory settings, but also in the real world. PMID:23950616
Expectations about Memory Change Across the Life Span Are Impacted By Aging Stereotypes

PubMed Central

Lineweaver, Tara T.; Berger, Andrea K.; Hertzog, Christopher

2008-01-01

This study examined whether expectations about memory change with age vary for different personality types. Four adjectives from each of Hummert’s age-stereotype trait sets were selected to create 11 adjective clusters varying in both valence (positive versus negative) and relevance to memory functioning. Three hundred and seventy three participants in three age groups rated the memory abilities of target adults, defined by the adjective clusters, across the adult life span. Consistent with past studies, participants believed in age-related memory decline. However, participants rated target adults with positive personality traits as having better memory ability and less age-related memory decline than target adults with negative personality traits. This effect was larger when the traits were relevant to memory than when they were not. Finally, older participants were more strongly influenced by both the valence and the relevance of the personality descriptions than younger participants. PMID:19290748
A new method for selectively enhancing hemisphere processing: voice frequency amplification influences the strength of attribute framing.

PubMed

McCormick, Michael; Seta, John J

2012-01-01

An attribute framing effect occurs when positive or negative associations produced by positive or negative frames are mapped onto evaluations resulting in a more favourable evaluation for the positively framed attribute. We used a new voice frequency manipulation to differentially enhance right versus left hemisphere processing. In doing so we found a strong attribute framing effect when a speaker with a low-frequency voice enhanced the contextual processing style of the right hemisphere. However, a framing effect was not obtained when a speaker with a high-frequency voice enhanced the inferential/analytical processing style of the left hemisphere. At the theoretical level our results provide evidence that the contextual processing style of the right hemisphere is especially susceptible to associative implications, such as those found in attribute framing manipulations. At the applied level we provide a simple method for altering the effectiveness of persuasion messages.
Prevalence and pathogens of subclinical mastitis in dairy goats in China.

PubMed

Zhao, Yanqing; Liu, Hui; Zhao, Xuanduo; Gao, Yang; Zhang, Miaotao; Chen, Dekun

2015-02-01

Subclinical mastitis, a costly disease for the dairy industry, is usually caused by intramammary bacterial infection. The aim of this study was to investigate the prevalence of and pathogens involved in subclinical mastitis in dairy goats in China. A total of 683 dairy goats in the main breeding areas of China were selected, and milk samples were collected. Out of these, 313 (45.82 %) goats were detected distinct or strong positive for subclinical mastitis by using California mastitis test. Among these positive goats, 209 milk samples were used to identify the causing agents by a multiplex PCR assay, and results were listed as follows: coagulase-negative staphylococci (59.52 %), Staphylococcus aureus (15.24 %), Escherichia coli (11.43 %), and Streptococcus spp. (10.95 %). In conclusion, subclinical mastitis is a highly prevalent disease in dairy goats in China, and coagulase-negative staphylococci are the predominant pathogens.
Feline mammary basal-like adenocarcinomas: a potential model for human triple-negative breast cancer (TNBC) with basal-like subtype.

PubMed

Wiese, David A; Thaiwong, Tuddow; Yuzbasiyan-Gurkan, Vilma; Kiupel, Matti

2013-09-03

Breast cancer is one of the leading causes of cancer deaths. Triple-negative breast cancer (TNBC), an immunophenotype defined by the absence of immunolabeling for estrogen receptor (ER), progesterone receptor (PR) and HER2 protein, has a highly aggressive behavior. A subpopulation of TNBCs exhibit a basal-like morphology with immunohistochemical positivity for cytokeratins 5/6 (CK5/6) and/or epidermal growth factor receptor (EGFR), and have a high incidence of BRCA (breast cancer susceptibility) mutations. Feline mammary adenocarcinomas (FMAs) are highly malignant and share a similar basal-like subtype. The purpose of this study was to classify FMAs according to the current human classification of breast cancer that includes evaluation of ER, PR and HER2 status and expression of basal CK 5/6 and EGFR. Furthermore, we selected triple negative, basal-like FMAs to screen for BRCA mutations similar to those described in human TNBC. Twenty four FMAs were classified according to the current human histologic breast cancer classification including immunohistochemistry (IHC) for ER, PR HER2, CK5/6 and EGFR. Genetic alteration and loss of heterozygosity of BRCA1 and BRCA2 genes were analyzed in triple negative, basal-like FMAs. IHC for ER, PR and HER2 identified 14 of the 24 (58%) FMAs as a triple negative. Furthermore, 11 of these 14 (79%) triple negative FMAs had a basal-like subtype. However, no genetic abnormalities were detected in BRCA1 and BRCA2 by direct sequencing and loss of heterozygosity analysis. FMAs are highly aggressive neoplasms that are commonly triple negative and exhibit a basal-like morphology. This is similar to human TNBC that are also commonly classified as a basal-like subtype. While sequencing of a select number of triple negative, basal-like FMAs and testing for loss of heterozygosity of BRCA1 and BRCA2 did not identify mutations similar to those described in human TNBC, further in-depth evaluation is required to elucidate a potential role of BRCA in the tumorigenesis of triple negative, basal-like FMAs. The strong similarities in clinical behavior, morphology and IHC phenotype suggest that triple negative, basal-like FMAs may be a suitable spontaneous animal model for studying novel therapeutic approaches against human basal-like TNBC.
A Parent-Offspring Trade-Off Limits the Evolution of an Ontogenetic Niche Shift.

PubMed

Ten Brink, Hanna; de Roos, André M

2017-07-01

Many free-living animal species, including the majority of fish, insects, and amphibians, change their food and habitat during their life. Even though these ontogenetic changes in niche are common, it is not well understood which ecological conditions have favored the evolution of these shifts. Using an adaptive dynamics approach, we show that it is evolutionarily advantageous to switch to an alternative food source in the course of ontogeny when this results in a higher intake rate for the switching consumers. Individuals are, however, not able to specialize on this new food source when this negatively affects the performance early in life on the original food source. Selection on these early life stages is so strong that in species with a complete diet shift, evolution results in large juveniles and adults that are maladapted to the alternative food source while their offspring are specialized on the original food source when young. These outcomes suggest strong selection to decouple the different life stages, such that they can maximize their performance on different food sources independently from each other. Metamorphosis could be a way to decouple the different life stages and therefore evolve in species that feed on multiple food sources during their life.
Psychological interventions in the management of common skin conditions

PubMed Central

Shenefelt, Philip D

2010-01-01

The nervous system and the skin develop next to each other in the embryo and remain intimately interconnected and interactive throughout life. The nervous system can influence skin conditions through psychoneuroimmunoendocrine mechanisms and through behaviors. Understanding the pathophysiology aids in selection of treatment plans for correcting the negative effects of the psyche on specific skin conditions. Medication options include standard psychotropic medications and alternative herbs and supplements. Other options include biofeedback, cognitive-behavioral methods, hypnosis, meditation, progressive relaxation, the placebo effect, and suggestion. When simple measures fail, combining medications with other therapeutic options may produce better results. Skin conditions that have strong psychophysiologic aspects may respond well to techniques such as biofeedback, cognitive-behavioral methods, hypnosis, meditation, or progressive relaxation that help to counteract stress. Treatment of primary psychiatric disorders that negatively influence skin conditions often results in improvement of those skin conditions. Abnormal conditions of the skin, hair, and nails can also influence the psyche negatively. Treatment of secondary psychiatric disorders such as anxiety or depression that are triggered or exacerbated by the appearance of these skin conditions or the associated discomfort may also be required. PMID:22110329
The Role of Trait and State Absorption in the Enjoyment of Music

PubMed Central

2016-01-01

Little is known about the role of state versus trait characteristics on our enjoyment of music. The aim of this study was to investigate the influence of state and trait absorption upon preference for music, particularly preference for music that evokes negative emotions. The sample consisted of 128 participants who were asked to listen to two pieces of self-selected music and rate the music on variables including preference and felt and expressed emotions. Participants completed a brief measure of state absorption after listening to each piece, and a trait absorption inventory. State absorption was strongly positively correlated with music preference, whereas trait absorption was not. Trait absorption was related to preference for negative emotions in music, with chi-square analyses demonstrating greater enjoyment of negative emotions in music among individuals with high trait absorption. This is the first study to show that state and trait absorption have separable and distinct effects on a listener’s music experience, with state characteristics impacting music enjoyment in the moment, and trait characteristics influencing music preference based on its emotional content. PMID:27828970
The Role of Trait and State Absorption in the Enjoyment of Music.

PubMed

Hall, Sarah E; Schubert, Emery; Wilson, Sarah J

2016-01-01

Little is known about the role of state versus trait characteristics on our enjoyment of music. The aim of this study was to investigate the influence of state and trait absorption upon preference for music, particularly preference for music that evokes negative emotions. The sample consisted of 128 participants who were asked to listen to two pieces of self-selected music and rate the music on variables including preference and felt and expressed emotions. Participants completed a brief measure of state absorption after listening to each piece, and a trait absorption inventory. State absorption was strongly positively correlated with music preference, whereas trait absorption was not. Trait absorption was related to preference for negative emotions in music, with chi-square analyses demonstrating greater enjoyment of negative emotions in music among individuals with high trait absorption. This is the first study to show that state and trait absorption have separable and distinct effects on a listener's music experience, with state characteristics impacting music enjoyment in the moment, and trait characteristics influencing music preference based on its emotional content.
Effects of attention on the neural processing of harmonic syntax in Western music.

PubMed

Loui, Psyche; Grent-'t-Jong, Tineke; Torpey, Dana; Woldorff, Marty

2005-12-01

The effects of selective attention on the neural response to the violation of musical syntax were investigated in the present study. Musical chord progressions were played to nonmusicians while Event-Related Potentials (ERPs) were recorded. The five-chord progressions included 61% harmonically expected cadences (I-I(6)-IV-V-I), 26% harmonically unexpected cadences (I-I(6)-IV-V-N(6)), and 13% with one of the five chords having an intensity fadeout across its duration. During the attended condition, subjects responded by pressing a button upon detecting a fadeout in volume; during the unattended condition, subjects were given reading comprehension materials and instructed to ignore all auditory stimuli. In response to the harmonic deviant, an Early Anterior Negativity (EAN) was observed at 150-300 ms in both attention conditions, but it was much larger in amplitude in the attended condition. A second scalp-negative deflection was also identified at 380-600 ms following the harmonic deviants; this Late Negativity onset earlier during the attended condition. These results suggest strong effects of attention on the neural processing of harmonic syntax.
Ion Selectivity Mechanism in a Bacterial Pentameric Ligand-Gated Ion Channel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fritsch, Sebastian M; Ivanov, Ivaylo N; Wang, Hailong

2011-01-01

The proton-gated ion channel from Gloeobacter violaceus (GLIC) is a prokaryotic homolog of the eukaryotic nicotinic acetylcholine receptor (nAChR) that responds to the binding of neurotransmitter acetylcholine and mediates fast signal transmission. Recent emergence of a high resolution crystal structure of GLIC captured in a potentially open state allowed detailed, atomic-level insight into ion conduction and selectivity mechanisms in these channels. Herein, we have examined the barriers to ion conduction and origins of ion selectivity in the GLIC channel by the construction of potential of mean force (PMF) profiles for sodium and chloride ions inside the transmembrane region. Our calculationsmore » reveal that the GLIC channel is open for a sodium ion to transport, but presents a ~10 kcal/mol free energy barrier for a chloride ion, which arises primarily from the unfavorable interactions with a ring of negatively charged glutamate residues (E-2 ) at the intracellular end and a ring of hydrophobic residues (I9 ) in the middle of the transmembrane domain. Our collective findings further suggest that the charge selection mechanism can, to a large extent, be attributed to the narrow intracellular end and a ring of glutamate residues in this position their strong negative electrostatics and ability to bind cations. By contrast, E19 at the extracellular entrance only plays a minor role in ion selectivity of GLIC. In addition to electrostatics, both ion hydration and protein dynamics are found to be crucial for ion conduction as well, which explains why a chloride ion experiences a much greater barrier than a sodium ion in the hydrophobic region of the pore.« less

Uneven segregation of sporophytic self-incompatibility alleles in Arabidopsis lyrata.

PubMed

Bechsgaard, J; Bataillon, T; Schierup, M H

2004-05-01

Self-incompatibility in Arabidopsis lyrata is sporophytically controlled by the multi-allelic S-locus. Self-incompatibility alleles (S-alleles) are under strong negative frequency dependent selection because pollen carrying common S-alleles have fewer mating opportunities. Population genetics theory predicts that deleterious alleles can accumulate if linked to the S-locus. This was tested by studying segregation of S-alleles in 11 large full sib families in A. lyrata. Significant segregation distortion leading to an up to fourfold difference in transmission rates was found in six families. Differences in transmission rates were not significantly different in reciprocal crosses and the distortions observed were compatible with selection acting at the gametic stage alone. The S-allele with the largest segregation advantage is also the most recessive, and is very common in natural populations concordant with its apparent segregation advantage. These results imply that frequencies of S-alleles in populations of A. lyrata cannot be predicted based on simple models of frequency-dependent selection alone.
Selective mode of action of guanidine-containing non-peptides at human NPFF receptors.

PubMed

Findeisen, Maria; Würker, Cäcilia; Rathmann, Daniel; Meier, René; Meiler, Jens; Olsson, Roger; Beck-Sickinger, Annette G

2012-07-12

The binding pocket of both NPFF receptors was investigated, focusing on subtype-selective behavior. By use of four nonpeptidic compounds and the peptide mimetics RF9 and BIBP3226, agonistic and antagonistic properties were characterized. A set of Ala receptor mutants was generated. The binding pocket was narrowed down to the upper part of transmembrane helices V, VI, VII and the extracellular loop 2. Positions 5.27 and 6.59 have been shown to have a strong impact on receptor activation and were suggested to form an acidic, negatively charged binding pocket in both NPFF receptor subtypes. Additionally, position 7.35 was identified to play an important role in functional selectivity. According to docking experiments, the aryl group of AC-216 interacts with position 7.35 in the NPFF(1) but not in the NPFF(2) receptor. These results provide distinct insights into the receptor specific binding pockets, which is necessary for the development of drugs to address the NPFF system.
Selective mode of action of guanidine-containing non-peptides at human NPFF receptors

PubMed Central

Findeisen, Maria; Würker, Cäcilia; Rathmann, Daniel; Meier, René; Meiler, Jens; Olsson, Roger; Beck-Sickinger, Annette G.

2012-01-01

The binding pocket of both NPFF receptors was investigated, focusing on subtype-selective behavior. By using four non-peptidic compounds and the peptide mimetics RF9 and BIBP3226 agonistic and antagonistic properties were characterized. A set of Ala receptor mutants was generated, the binding pocket was narrowed down to the upper part of transmembrane helices V, VI, VII, and the extracellular loop 2. Positions 5.27 and 6.59 have been shown to have a strong impact on receptor activation and were suggested to form an acidic, negatively charged binding pocket in both NPFF receptor subtypes. Additionally, position 7.35 was identified to play an important role in functional selectivity. According to docking experiments, the aryl group of AC-216 interacts with position 7.35 in the NPFF1 but not in the NPFF2 receptor. These results provide distinct insights into the receptor specific binding pockets, which is necessary for the development of drugs to address the NPFF system. PMID:22708927
Simultaneous separation of inorganic anions and metal-citrate complexes on a zwitterionic stationary phase with on-column complexation.

PubMed

Nesterenko, Ekaterina P; Nesterenko, Pavel N; Paull, Brett

2008-12-05

The retention and separation selectivity of inorganic anions and on-column derivatised negatively charged citrate or oxalate metal complexes on reversed-phase stationary phases dynamically coated with N-(dodecyl-N,N-dimethylammonio)undecanoate (DDMAU) has been investigated. The retention mechanism for the metal-citrate complexes was predominantly anion exchange, although the amphoteric/zwitterionic nature of the stationary phase coating undoubtedly also contributed to the unusual separation selectivity shown. A mixture of 10 inorganic anions and metal cations was achieved using a 20 cm monolithic DDMAU modified column and a 1 mM citrate eluent, pH 4.0, flow rate equal to 0.8 mL/min. Selectivity was found to be strongly pH dependent, allowing additional scope for manipulation of solute retention, and thus application to complex samples. This is illustrated with the analysis of an acidic mine drainage sample with a range of inorganic anions and transition metal cations, varying significantly in their concentrations levels.
Trans-species polymorphism at antimicrobial innate immunity cathelicidin genes of Atlantic cod and related species

PubMed Central

Árnason, Einar

2015-01-01

Natural selection, the most important force in evolution, comes in three forms. Negative purifying selection removes deleterious variation and maintains adaptations. Positive directional selection fixes beneficial variants, producing new adaptations. Balancing selection maintains variation in a population. Important mechanisms of balancing selection include heterozygote advantage, frequency-dependent advantage of rarity, and local and fluctuating episodic selection. A rare pathogen gains an advantage because host defenses are predominantly effective against prevalent types. Similarly, a rare immune variant gives its host an advantage because the prevalent pathogens cannot escape the host’s apostatic defense. Due to the stochastic nature of evolution, neutral variation may accumulate on genealogical branches, but trans-species polymorphisms are rare under neutrality and are strong evidence for balancing selection. Balanced polymorphism maintains diversity at the major histocompatibility complex (MHC) in vertebrates. The Atlantic cod is missing genes for both MHC-II and CD4, vital parts of the adaptive immune system. Nevertheless, cod are healthy in their ecological niche, maintaining large populations that support major commercial fisheries. Innate immunity is of interest from an evolutionary perspective, particularly in taxa lacking adaptive immunity. Here, we analyze extensive amino acid and nucleotide polymorphisms of the cathelicidin gene family in Atlantic cod and closely related taxa. There are three major clusters, Cath1, Cath2, and Cath3, that we consider to be paralogous genes. There is extensive nucleotide and amino acid allelic variation between and within clusters. The major feature of the results is that the variation clusters by alleles and not by species in phylogenetic trees and discriminant analysis of principal components. Variation within the three groups shows trans-species polymorphism that is older than speciation and that is suggestive of balancing selection maintaining the variation. Using Bayesian and likelihood methods positive and negative selection is evident at sites in the conserved part of the genes and, to a larger extent, in the active part which also shows episodic diversifying selection, further supporting the argument for balancing selection. PMID:26038731
Antibacterial activities of fluorescent nano assembled triphenylamine phosphonium ionic liquids.

PubMed

Brunel, Frédéric; Lautard, Christelle; Garzino, Frédéric; Giorgio, Suzanne; Raimundo, Jean M; Bolla, Jean M; Camplo, Michel

2016-08-01

Staphylococcus aureus, a Gram positive coccal bacterium is a major cause of nosocomial infection. We report the synthesis of new triphenylamine phosphonium ionic liquids which are able to self-assemble into multiwall nanoassemblies and to reveal a strong bactericidal activity (MIC=0.5mg/L) for Gram positive bacteria (including resistant strains) comparable to that of standard antibiotics. Time kill, metabolism and fluorescence confocal microscopy studies show a quasi-instantaneously penetration of the nanoassemblies inside the bacteria resulting of a rapid blocking (30min) of their proliferation. As confirmed by rezasurin reduction monitoring, these compounds strongly affect the bacterial metabolism and a Gram positive versus Gram negative selectivity is clearly observed. These fluorescent phosphonium ionic liquid might constitute a useful tool for both translocation studies and to tackle infectious diseases related to the field of implantology. Copyright © 2016 Elsevier Ltd. All rights reserved.
Advancing understanding of affect labeling with dynamic causal modeling

PubMed Central

Torrisi, Salvatore J.; Lieberman, Matthew D.; Bookheimer, Susan Y.; Altshuler, Lori L.

2013-01-01

Mechanistic understandings of forms of incidental emotion regulation have implications for basic and translational research in the affective sciences. In this study we applied Dynamic Causal Modeling (DCM) for fMRI to a common paradigm of labeling facial affect to elucidate prefrontal to subcortical influences. Four brain regions were used to model affect labeling, including right ventrolateral prefrontal cortex (vlPFC), amygdala and Broca’s area. 64 models were compared, for each of 45 healthy subjects. Family level inference split the model space to a likely driving input and Bayesian Model Selection within the winning family of 32 models revealed a strong pattern of endogenous network connectivity. Modulatory effects of labeling were most prominently observed following Bayesian Model Averaging, with the dampening influence on amygdala originating from Broca’s area but much more strongly from right vlPFC. These results solidify and extend previous correlation and regression-based estimations of negative corticolimbic coupling. PMID:23774393
Raman scattering excitation spectroscopy of monolayer WS2.

PubMed

Molas, Maciej R; Nogajewski, Karol; Potemski, Marek; Babiński, Adam

2017-07-11

Resonant Raman scattering is investigated in monolayer WS 2 at low temperature with the aid of an unconventional technique, i.e., Raman scattering excitation (RSE) spectroscopy. The RSE spectrum is made up by sweeping the excitation energy, when the detection energy is fixed in resonance with excitonic transitions related to either neutral or charged excitons. We demonstrate that the shape of the RSE spectrum strongly depends on the selected detection energy. The resonance of outgoing light with the neutral exciton leads to an extremely rich RSE spectrum, which displays several Raman scattering features not reported so far, while no clear effect on the associated background photoluminescence is observed. Instead, when the outgoing photons resonate with the negatively charged exciton, a strong enhancement of the related emission occurs. Presented results show that the RSE spectroscopy can be a useful technique to study electron-phonon interactions in thin layers of transition metal dichalcogenides.
Which lamp will be optimum to eye? Incandescent, fluorescent or LED etc

PubMed Central

Chen, Liang; Zhang, Xiao-Wei

2014-01-01

Low frequency flicker, high frequency flicker, strong light, strong blue light, infrared, ultraviolet, electromagnetic radiation, ripple flicker and dimming flicker produced by different lamps have negative impact on vision, eyes and health. Negative impact on eyes resulting in myopia or cataract etc: the solution is to remove all the negative factors by applying upright lighting technology and that is optimum to vision, eyes and health. PMID:24634884
Which lamp will be optimum to eye? Incandescent, fluorescent or LED etc.

PubMed

Chen, Liang; Zhang, Xiao-Wei

2014-01-01

Low frequency flicker, high frequency flicker, strong light, strong blue light, infrared, ultraviolet, electromagnetic radiation, ripple flicker and dimming flicker produced by different lamps have negative impact on vision, eyes and health. Negative impact on eyes resulting in myopia or cataract etc: the solution is to remove all the negative factors by applying upright lighting technology and that is optimum to vision, eyes and health.
Antimicrobial Use and Veterinary Care among Agro-Pastoralists in Northern Tanzania

PubMed Central

Quinlan, Marsha B.; Subbiah, Murugan; Call, Douglas R.; Roulette, Casey J.; Roulette, Jennifer W.; Roth, Adam; Matthews, Louise; Quinlan, Robert J.

2017-01-01

Frequent and unregulated use of antimicrobials (AM) in livestock requires public health attention as a likely selection pressure for resistant bacteria. Studies among small-holders, who own a large percentage of the world’s livestock, are vital for understanding how practices involving AM use might influence resistance. We present a cultural-ecological mixed-methods analysis to explore sectors of veterinary care, loosely regulated AM use, and human exposure to AMs through meat and milk consumption across three rural to peri-urban Tanzanian ethnic groups (N = 415 households). Reported use of self-administered AMs varied by ethnic group (Maasai: 74%, Arusha: 21%, Chagga: 1%) as did consultation with professional veterinarians (Maasai: 36%, Arusha: 45%, Chagga: 96%) and observation of withdrawal of meat and milk from consumption during and following AM treatment (Maasai: 7%, Arusha: 72%, Chagga: 96%). The antibiotic oxytetracycline was by far the most common AM in this sample. Within ethnic groups, herd composition differences, particularly size of small-stock and cattle herds, were most strongly associated with differences in lay AM use. Among the Arusha, proxies for urbanization, including owning transportation and reliance on “zero-grazing” herds had the strongest positive associations with veterinarian consultation, while distance to urban centers was negatively associated. For Maasai, consultation was negatively associated with use of traditional healers or veterinary drug-shops. Observation of withdrawal was most strongly associated with owning technology among Maasai while Arusha observance displayed seasonal differences. This “One-Health” analysis suggests that livelihood and cultural niche factors, through their association with practices in smallholder populations, provide insight into the selection pressures that may contribute to the evolution and dissemination of antimicrobial resistance. PMID:28125722
Antimicrobial Use and Veterinary Care among Agro-Pastoralists in Northern Tanzania.

PubMed

Caudell, Mark A; Quinlan, Marsha B; Subbiah, Murugan; Call, Douglas R; Roulette, Casey J; Roulette, Jennifer W; Roth, Adam; Matthews, Louise; Quinlan, Robert J

2017-01-01

Frequent and unregulated use of antimicrobials (AM) in livestock requires public health attention as a likely selection pressure for resistant bacteria. Studies among small-holders, who own a large percentage of the world's livestock, are vital for understanding how practices involving AM use might influence resistance. We present a cultural-ecological mixed-methods analysis to explore sectors of veterinary care, loosely regulated AM use, and human exposure to AMs through meat and milk consumption across three rural to peri-urban Tanzanian ethnic groups (N = 415 households). Reported use of self-administered AMs varied by ethnic group (Maasai: 74%, Arusha: 21%, Chagga: 1%) as did consultation with professional veterinarians (Maasai: 36%, Arusha: 45%, Chagga: 96%) and observation of withdrawal of meat and milk from consumption during and following AM treatment (Maasai: 7%, Arusha: 72%, Chagga: 96%). The antibiotic oxytetracycline was by far the most common AM in this sample. Within ethnic groups, herd composition differences, particularly size of small-stock and cattle herds, were most strongly associated with differences in lay AM use. Among the Arusha, proxies for urbanization, including owning transportation and reliance on "zero-grazing" herds had the strongest positive associations with veterinarian consultation, while distance to urban centers was negatively associated. For Maasai, consultation was negatively associated with use of traditional healers or veterinary drug-shops. Observation of withdrawal was most strongly associated with owning technology among Maasai while Arusha observance displayed seasonal differences. This "One-Health" analysis suggests that livelihood and cultural niche factors, through their association with practices in smallholder populations, provide insight into the selection pressures that may contribute to the evolution and dissemination of antimicrobial resistance.
Selection Shapes Transcriptional Logic and Regulatory Specialization in Genetic Networks.

PubMed

Fogelmark, Karl; Peterson, Carsten; Troein, Carl

2016-01-01

Living organisms need to regulate their gene expression in response to environmental signals and internal cues. This is a computational task where genes act as logic gates that connect to form transcriptional networks, which are shaped at all scales by evolution. Large-scale mutations such as gene duplications and deletions add and remove network components, whereas smaller mutations alter the connections between them. Selection determines what mutations are accepted, but its importance for shaping the resulting networks has been debated. To investigate the effects of selection in the shaping of transcriptional networks, we derive transcriptional logic from a combinatorially powerful yet tractable model of the binding between DNA and transcription factors. By evolving the resulting networks based on their ability to function as either a simple decision system or a circadian clock, we obtain information on the regulation and logic rules encoded in functional transcriptional networks. Comparisons are made between networks evolved for different functions, as well as with structurally equivalent but non-functional (neutrally evolved) networks, and predictions are validated against the transcriptional network of E. coli. We find that the logic rules governing gene expression depend on the function performed by the network. Unlike the decision systems, the circadian clocks show strong cooperative binding and negative regulation, which achieves tight temporal control of gene expression. Furthermore, we find that transcription factors act preferentially as either activators or repressors, both when binding multiple sites for a single target gene and globally in the transcriptional networks. This separation into positive and negative regulators requires gene duplications, which highlights the interplay between mutation and selection in shaping the transcriptional networks.
Optimizing trial design in pharmacogenetics research: comparing a fixed parallel group, group sequential, and adaptive selection design on sample size requirements.

PubMed

Boessen, Ruud; van der Baan, Frederieke; Groenwold, Rolf; Egberts, Antoine; Klungel, Olaf; Grobbee, Diederick; Knol, Mirjam; Roes, Kit

2013-01-01

Two-stage clinical trial designs may be efficient in pharmacogenetics research when there is some but inconclusive evidence of effect modification by a genomic marker. Two-stage designs allow to stop early for efficacy or futility and can offer the additional opportunity to enrich the study population to a specific patient subgroup after an interim analysis. This study compared sample size requirements for fixed parallel group, group sequential, and adaptive selection designs with equal overall power and control of the family-wise type I error rate. The designs were evaluated across scenarios that defined the effect sizes in the marker positive and marker negative subgroups and the prevalence of marker positive patients in the overall study population. Effect sizes were chosen to reflect realistic planning scenarios, where at least some effect is present in the marker negative subgroup. In addition, scenarios were considered in which the assumed 'true' subgroup effects (i.e., the postulated effects) differed from those hypothesized at the planning stage. As expected, both two-stage designs generally required fewer patients than a fixed parallel group design, and the advantage increased as the difference between subgroups increased. The adaptive selection design added little further reduction in sample size, as compared with the group sequential design, when the postulated effect sizes were equal to those hypothesized at the planning stage. However, when the postulated effects deviated strongly in favor of enrichment, the comparative advantage of the adaptive selection design increased, which precisely reflects the adaptive nature of the design. Copyright © 2013 John Wiley & Sons, Ltd.
Effect of plasma-induced surface charging on catalytic processes: application to CO2 activation

NASA Astrophysics Data System (ADS)

Bal, Kristof M.; Huygh, Stijn; Bogaerts, Annemie; Neyts, Erik C.

2018-02-01

Understanding the nature and effect of the multitude of plasma-surface interactions in plasma catalysis is a crucial requirement for further process development and improvement. A particularly intriguing and rather unique property of a plasma-catalytic setup is the ability of the plasma to modify the electronic structure, and hence chemical properties, of the catalyst through charging, i.e. the absorption of excess electrons. In this work, we develop a quantum chemical model based on density functional theory to study excess negative surface charges in a heterogeneous catalyst exposed to a plasma. This method is specifically applied to investigate plasma-catalytic CO2 activation on supported M/Al2O3 (M = Ti, Ni, Cu) single atom catalysts. We find that (1) the presence of a negative surface charge dramatically improves the reductive power of the catalyst, strongly promoting the splitting of CO2 to CO and oxygen, and (2) the relative activity of the investigated transition metals is also changed upon charging, suggesting that controlled surface charging is a powerful additional parameter to tune catalyst activity and selectivity. These results strongly point to plasma-induced surface charging of the catalyst as an important factor contributing to the plasma-catalyst synergistic effects frequently reported for plasma catalysis.
Opposing selection and environmental variation modify optimal timing of breeding.

PubMed

Tarwater, Corey E; Beissinger, Steven R

2013-09-17

Studies of evolution in wild populations often find that the heritable phenotypic traits of individuals producing the most offspring do not increase proportionally in the population. This paradox may arise when phenotypic traits influence both fecundity and viability and when there is a tradeoff between these fitness components, leading to opposing selection. Such tradeoffs are the foundation of life history theory, but they are rarely investigated in selection studies. Timing of breeding is a classic example of a heritable trait under directional selection that does not result in an evolutionary response. Using a 22-y study of a tropical parrot, we show that opposing viability and fecundity selection on the timing of breeding is common and affects optimal breeding date, defined by maximization of fitness. After accounting for sampling error, the directions of viability (positive) and fecundity (negative) selection were consistent, but the magnitude of selection fluctuated among years. Environmental conditions (rainfall and breeding density) primarily and breeding experience secondarily modified selection, shifting optimal timing among individuals and years. In contrast to other studies, viability selection was as strong as fecundity selection, late-born juveniles had greater survival than early-born juveniles, and breeding later in the year increased fitness under opposing selection. Our findings provide support for life history tradeoffs influencing selection on phenotypic traits, highlight the need to unify selection and life history theory, and illustrate the importance of monitoring survival as well as reproduction for understanding phenological responses to climate change.
Glacial history affected phenotypic differentiation in the alpine plant, Campanula thyrsoides.

PubMed

Scheepens, J F; Frei, Eva S; Stöcklin, Jürg

2013-01-01

Numerous widespread Alpine plant species show molecular differentiation among populations from distinct regions. This has been explained as the result of genetic drift during glacial survival in isolated refugia along the border of the European Alps. Since genetic drift may affect molecular markers and phenotypic traits alike, we asked whether phenotypic differentiation mirrors molecular patterns among Alpine plant populations from different regions. Phenotypic traits can be under selection, so we additionally investigated whether part of the phenotypic differentiation can be explained by past selection and/or current adaptation. Using the monocarpic Campanula thyrsoides as our study species, a common garden experiment with plants from 21 populations from four phylogeographic groups located in regions across the Alps and the Jura Mountains was performed to test for differentiation in morphological and phenological traits. Past selection was investigated by comparing phenotypic differentiation among and within regions with molecular differentiation among and within regions. The common garden results indicated regional differentiation among populations for all investigated phenotypic traits, particularly in phenology. Delayed flowering in plants from the South-eastern Alps suggested adaptation to long sub-mediterranean summers and contrasted with earlier flowering of plants experiencing shorter growing seasons in regions with higher elevation to the West. Comparisons between molecular and phenotypic differentiation revealed diversifying selection among regions in height and biomass, which is consistent with adaptation to environmental conditions in glacial refugia. Within regions, past selection acted against strong diversification for most phenotypic traits, causing restricted postglacial adaptation. Evidence consistent with post-glacial adaptation was also given by negative correlation coefficients between several phenotypic traits and elevation of the population's origin. In conclusion, our study suggests that, irrespective of adaptation of plants to their current environment, glacial history can have a strong and long-lasting influence on the phenotypic evolution of Alpine plants.
Comparative analysis of protein evolution in the genome of pre-epidemic and epidemic Zika virus.

PubMed

Ramaiah, Arunachalam; Dai, Lei; Contreras, Deisy; Sinha, Sanjeev; Sun, Ren; Arumugaswami, Vaithilingaraja

2017-07-01

Zika virus (ZIKV) causes microcephaly in congenital infection, neurological disorders, and poor pregnancy outcome and no vaccine is available for use in humans or approved. Although ZIKV was first discovered in 1947, the exact mechanism of virus replication and pathogenesis remains unknown. Recent outbreaks of Zika virus in the Americas clearly suggest a human-mosquito cycle or urban cycle of transmission. Understanding the conserved and adaptive features in the evolution of ZIKV genome will provide a hint on the mechanism of ZIKV adaptation to a new cycle of transmission. Here, we show comprehensive analysis of protein evolution of ZIKV strains including the current 2015-16 outbreak. To identify the constraints on ZIKV evolution, selection pressure at individual codons, immune epitopes and co-evolving sites were analyzed. Phylogenetic trees show that the ZIKV strains of the Asian genotype form distinct cluster and share a common ancestor with African genotype. The TMRCA (Time to the Most Recent Common Ancestor) for the Asian lineage and the subsequently evolved Asian human strains was calculated at 88 and 34years ago, respectively. The proteome of current 2015/16 epidemic ZIKV strains of Asian genotype was found to be genetically conserved due to genome-wide negative selection, with limited positive selection. We identified a total of 16 amino acid substitutions in the epidemic and pre-epidemic strains from human, mosquito, and monkey hosts. Negatively selected amino acid sites of Envelope protein (E-protein) (positions 69, 166, and 174) and NS5 (292, 345, and 587) were located in central dimerization domains and C-terminal RNA-directed RNA polymerase regions, respectively. The predicted 137 (92 CD4 TCEs; 45 CD8 TCEs) immunogenic peptide chains comprising negatively selected amino acid sites can be considered as suitable target for sub-unit vaccine development, as these sites are less likely to generate immune-escape variants due to strong functional constrains operating on them. The targeted changes at the amino acid level may contribute to better adaptation of ZIKV strains to human-mosquito cycle or urban cycle of transmission. Copyright © 2017. Published by Elsevier B.V.
Evolutionary games on cycles with strong selection

NASA Astrophysics Data System (ADS)

Altrock, P. M.; Traulsen, A.; Nowak, M. A.

2017-02-01

Evolutionary games on graphs describe how strategic interactions and population structure determine evolutionary success, quantified by the probability that a single mutant takes over a population. Graph structures, compared to the well-mixed case, can act as amplifiers or suppressors of selection by increasing or decreasing the fixation probability of a beneficial mutant. Properties of the associated mean fixation times can be more intricate, especially when selection is strong. The intuition is that fixation of a beneficial mutant happens fast in a dominance game, that fixation takes very long in a coexistence game, and that strong selection eliminates demographic noise. Here we show that these intuitions can be misleading in structured populations. We analyze mean fixation times on the cycle graph under strong frequency-dependent selection for two different microscopic evolutionary update rules (death-birth and birth-death). We establish exact analytical results for fixation times under strong selection and show that there are coexistence games in which fixation occurs in time polynomial in population size. Depending on the underlying game, we observe inherence of demographic noise even under strong selection if the process is driven by random death before selection for birth of an offspring (death-birth update). In contrast, if selection for an offspring occurs before random removal (birth-death update), then strong selection can remove demographic noise almost entirely.
Intelligence, Education, and Facets of Job Satisfaction.

ERIC Educational Resources Information Center

Ganzach, Yoav

2003-01-01

Analysis of two sets of National Longitudinal Survey data found that intelligence had a strong negative effect on intrinsic satisfaction, little effect on pay satisfaction, and positive association with desired job complexity, not expected pay. Education had a strong negative effect on pay satisfaction, little effect on intrinsic satisfaction, and…

Asymmetric band gaps in a Rashba film system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carbone, C.; Moras, P.; Sheverdyaeva, P. M.

The joint effect of exchange and Rashba spin-orbit interactions is examined on the surface and quantum well states of Ag 2 Bi -terminated Ag films grown on ferromagnetic Fe(110). The system displays a particular combination of time-reversal and translational symmetry breaking that strongly influences its electronic structure. Angle-resolved photoemission reveals asymmetric band-gap openings, due to spin-selective hybridization between Rashba-split surface states and exchange-split quantum well states. This results in an unequal number of states along positive and negative reciprocal space directions. We suggest that the peculiar asymmetry of the discovered electronic structure can have significant influence on spin-polarized transport properties.
Divergent selection along climatic gradients in a rare central European endemic species, Saxifraga sponhemica

PubMed Central

Walisch, Tania J.; Colling, Guy; Bodenseh, Melanie; Matthies, Diethart

2015-01-01

Background and Aims The effects of habitat fragmentation on quantitative genetic variation in plant populations are still poorly known. Saxifraga sponhemica is a rare endemic of Central Europe with a disjunct distribution, and a stable and specialized habitat of treeless screes and cliffs. This study therefore used S. sponhemica as a model species to compare quantitative and molecular variation in order to explore (1) the relative importance of drift and selection in shaping the distribution of quantitative genetic variation along climatic gradients; (2) the relationship between plant fitness, quantitative genetic variation, molecular genetic variation and population size; and (3) the relationship between the differentiation of a trait among populations and its evolvability. Methods Genetic variation within and among 22 populations from the whole distribution area of S. sponhemica was studied using RAPD (random amplified polymorphic DNA) markers, and climatic variables were obtained for each site. Seeds were collected from each population and germinated, and seedlings were transplanted into a common garden for determination of variation in plant traits. Key Results In contrast to previous results from rare plant species, strong evidence was found for divergent selection. Most population trait means of S. sponhemica were significantly related to climate gradients, indicating adaptation. Quantitative genetic differentiation increased with geographical distance, even when neutral molecular divergence was controlled for, and QST exceeded FST for some traits. The evolvability of traits was negatively correlated with the degree of differentiation among populations (QST), i.e. traits under strong selection showed little genetic variation within populations. The evolutionary potential of a population was not related to its size, the performance of the population or its neutral genetic diversity. However, performance in the common garden was lower for plants from populations with reduced molecular genetic variation, suggesting inbreeding depression due to genetic erosion. Conclusions The findings suggest that studies of molecular and quantitative genetic variation may provide complementary insights important for the conservation of rare species. The strong differentiation of quantitative traits among populations shows that selection can be an important force for structuring variation in evolutionarily important traits even for rare endemic species restricted to very specific habitats. PMID:25862244
Strong Turbulence in Alkali Halide Negative Ion Plasmas

NASA Astrophysics Data System (ADS)

Sheehan, Daniel

1999-11-01

Negative ion plasmas (NIPs) are charge-neutral plasmas in which the negative charge is dominated by negative ions rather than electrons. They are found in laser discharges, combustion products, semiconductor manufacturing processes, stellar atmospheres, pulsar magnetospheres, and the Earth's ionosphere, both naturally and man-made. They often display signatures of strong turbulence^1. Development of a novel, compact, unmagnetized alkali halide (MX) NIP source will be discussed, it incorporating a ohmically-heated incandescent (2500K) tantulum solenoid (3cm dia, 15 cm long) with heat shields. The solenoid ionizes the MX vapor and confines contaminant electrons, allowing a very dry (electron-free) source. Plasma densities of 10^10 cm-3 and positive to negative ion mass ratios of 1 <= fracm_+m- <= 20 are achievable. The source will allow tests of strong turbulence theory^2. 1 Sheehan, D.P., et al., Phys. Fluids B5, 1593 (1993). 2 Tsytovich, V. and Wharton, C.W., Comm. Plasma Phys. Cont. Fusion 4, 91 (1978).
NMR detects molecular interactions of graphene with aromatic and aliphatic hydrocarbons in water

NASA Astrophysics Data System (ADS)

Bichenkova, Elena V.; Raju, Arun P. A.; Burusco, Kepa K.; Kinloch, Ian A.; Novoselov, Kostya S.; Clarke, David J.

2018-03-01

Polyaromatic carbon is widely held to be strongly diamagnetic and hydrophobic, with textbook van der Waals and ‘π-stacked’ binding of hydrocarbons, which disrupt their self-assembled supramolecular structures. The NMR of organic molecules sequestered by polyaromatic carbon is expected to be dominated by shielding from the orbital diamagnetism of π electrons. We report the first evidence of very different polar and magnetic behavior in water, wherein graphene remained well-dispersed after extensive dialysis and behaved as a 1H-NMR-silent ghost. Magnetic effects dominated the NMR of organic structures which interacted with graphene, with changes in spin-spin coupling, vast increase in relaxation, line broadening and decrease in NMR peak heights when bound to graphene. However, the interactions were weak, reversible and did not disrupt organic self-assemblies reliant on hydrophobic ‘π-stacking’, even when substantially sequestered on the surface of graphene by the high surface area available. Interacting assemblies of aromatic molecules retained their strongly-shielded NMR signals and remained within self-assembled structures, with slower rates of diffusion from association with graphene, but with no further shielding from graphene. Binding to graphene was selective for positively-charged organic assemblies, weaker for non-aromatic and negligible for strongly-negatively-charged molecules, presumably repelled by a negative zeta potential of graphene in water. Stronger binders, or considerable excess of weaker binders readily reversed physisorption, with no evidence of structural changes from chemisorption. The fundamental nature of these different electronic interactions between organic and polyaromatic carbon is considered with relevance to electronics, charge storage, sensor, medical, pharmaceutical and environmental research.
Resonant absorption and amplification of circularly-polarized waves in inhomogeneous chiral media.

PubMed

Kim, Seulong; Kim, Kihong

2016-01-25

It has been found that in the media where the dielectric permittivity ε or the magnetic permeability μ is near zero and in transition metamaterials where ε or μ changes from positive to negative values, there occur a strong absorption or amplification of the electromagnetic wave energy in the presence of an infinitesimally small damping or gain and a strong enhancement of the electromagnetic fields. We attribute these phenomena to the mode conversion of transverse electromagnetic waves into longitudinal plasma oscillations and its inverse process. In this paper, we study analogous phenomena occurring in chiral media theoretically using the invariant imbedding method. In uniform isotropic chiral media, right-circularly-polarized and left-circularly-polarized waves are the eigen-modes of propagation with different effective refractive indices n(+) and n(-), whereas in the chiral media with a nonuniform impedance variation, they are no longer the eigenmodes and are coupled to each other. We find that both in uniform chiral slabs where either n(+) or n(-) is near zero and in chiral transition metamaterials where n(+) or n(-) changes from positive to negative values, a strong absorption or amplification of circularly-polarized waves occurs in the presence of an infinitesimally small damping or gain. We present detailed calculations of the mode conversion coefficient, which measures the fraction of the electromagnetic wave energy absorbed into the medium, for various configurations of ε and μ with an emphasis on the influence of a nonuniform impedance. We propose possible applications of these phenomena to linear and nonlinear optical devices that react selectively to the helicity of the circular polarization.
Predation and the evolution of complex oviposition behaviour in Amazon rainforest frogs.

PubMed

Magnusson, William E; Hero, Jean-Marc

1991-05-01

Terrestrial oviposition with free-living aquatic larvae is a common reproductive mode used by amphibians within the central Amazonian rainforest. We investigated the factors presently associated with diversity of microhabitats (waterbodies) that may be maintaining the diversity of reproductive modes. In particular, desiccation, predation by fish, competition with other anurans and water quality were examined in 11 waterbodies as possible forces leading to the evolution of terrestrial oviposition. Predation experiments demonstrated that fish generally do not eat anuran eggs, and that predacious tadpoles and dytiscid beetle larvae are voracious predators of anuran eggs. The percentage of species with terrestrial oviposition was only weakly correlated with the occurrence of pond drying, pH and oxygen concentration, suggesting that anurans in this tropical community are able to use the range of water quality available for egg development. There was a tendency for terrestrial oviposition to be associated with the number of species of tadpoles using the waterbody, but we consider this to be spurious as there was no obvious competitive mechanism that could result in this relationship. The percentage of species with terrestrial oviposition was significantly positively related to our index of egg predation pressure, and negatively related to our index of fish biomass. Egg predation pressure was also negatively related to the index of fish biomass. These results allow us to discount as improbable the hypothesis that predation by fish on anuran eggs was an important selective pressure leading to terrestrial oviposition in this community. The strong positive relationship between terrestrial oviposition and our index of egg predation pressure indicates that these predators have exerted, and are exerting, a significant selective pressure for terrestrial oviposition. The strong negative relationship between the occurrence of fish and the egg predators suggests the surprising conclusion that the presence of fish actually protects aquatic anuran eggs from predation in this tropical system, and allows aquatic oviposition to dominate only in those waterbodies with moderate to high densities of fish. Our results suggest that terrestrial oviposition is a "fixed predator avoidance" trait.
A 660-Kb Deletion with Antagonistic Effects on Fertility and Milk Production Segregates at High Frequency in Nordic Red Cattle: Additional Evidence for the Common Occurrence of Balancing Selection in Livestock

PubMed Central

Kadri, Naveen Kumar; Sahana, Goutam; Charlier, Carole; Iso-Touru, Terhi; Guldbrandtsen, Bernt; Karim, Latifa; Nielsen, Ulrik Sander; Panitz, Frank; Aamand, Gert Pedersen; Schulman, Nina; Georges, Michel; Vilkki, Johanna; Lund, Mogens Sandø; Druet, Tom

2014-01-01

In dairy cattle, the widespread use of artificial insemination has resulted in increased selection intensity, which has led to spectacular increase in productivity. However, cow fertility has concomitantly severely declined. It is generally assumed that this reduction is primarily due to the negative energy balance of high-producing cows at the peak of lactation. We herein describe the fine-mapping of a major fertility QTL in Nordic Red cattle, and identify a 660-kb deletion encompassing four genes as the causative variant. We show that the deletion is a recessive embryonically lethal mutation. This probably results from the loss of RNASEH2B, which is known to cause embryonic death in mice. Despite its dramatic effect on fertility, 13%, 23% and 32% of the animals carry the deletion in Danish, Swedish and Finnish Red Cattle, respectively. To explain this, we searched for favorable effects on other traits and found that the deletion has strong positive effects on milk yield. This study demonstrates that embryonic lethal mutations account for a non-negligible fraction of the decline in fertility of domestic cattle, and that associated positive effects on milk yield may account for part of the negative genetic correlation. Our study adds to the evidence that structural variants contribute to animal phenotypic variation, and that balancing selection might be more common in livestock species than previously appreciated. PMID:24391517
Probing the Selectivity and Protein•Protein Interactions of a Non-Reducing Fungal Polyketide Synthase Using Mechanism-Based Crosslinkers

PubMed Central

Bruegger, Joel; Haushalter, Bob; Vagstad, Anna; Shakya, Gaurav; Mih, Nathan; Townsend, Craig A.; Burkart, Michael D.; Tsai, Shiou-Chuan

2013-01-01

SUMMARY Protein•protein interactions, which often involve interactions between an acyl carrier protein (ACP) and its partner enzymes, are important for coordinating polyketide biosynthesis. However, the nature of such interactions is not well understood, especially in the fungal non-reducing polyketide synthases (NR-PKSs) that biosynthesize toxic and pharmaceutically important polyketides. Here, we employ a mechanism-based crosslinker to successfully probe ACP and ketosynthase (KS) domain interactions in NR-PKSs. We found that crosslinking efficiency is closely correlated with the strength of ACP•KS interactions, and that KS demonstrates strong starter unit selectivity. We further identified positively charged surface residues by KS mutagenesis, which mediate key interactions with the negatively-charged ACP surface. Such complementary/matching contact pairs can serve as “adapter surfaces” for future efforts to generate new polyketides using NR-PKSs. PMID:23993461
Global dynamics of selective attention and its lapses in primary auditory cortex.

PubMed

Lakatos, Peter; Barczak, Annamaria; Neymotin, Samuel A; McGinnis, Tammy; Ross, Deborah; Javitt, Daniel C; O'Connell, Monica Noelle

2016-12-01

Previous research demonstrated that while selectively attending to relevant aspects of the external world, the brain extracts pertinent information by aligning its neuronal oscillations to key time points of stimuli or their sampling by sensory organs. This alignment mechanism is termed oscillatory entrainment. We investigated the global, long-timescale dynamics of this mechanism in the primary auditory cortex of nonhuman primates, and hypothesized that lapses of entrainment would correspond to lapses of attention. By examining electrophysiological and behavioral measures, we observed that besides the lack of entrainment by external stimuli, attentional lapses were also characterized by high-amplitude alpha oscillations, with alpha frequency structuring of neuronal ensemble and single-unit operations. Entrainment and alpha-oscillation-dominated periods were strongly anticorrelated and fluctuated rhythmically at an ultra-slow rate. Our results indicate that these two distinct brain states represent externally versus internally oriented computational resources engaged by large-scale task-positive and task-negative functional networks.
In silico selection of therapeutic antibodies for development: Viscosity, clearance, and chemical stability

PubMed Central

Sharma, Vikas K.; Patapoff, Thomas W.; Kabakoff, Bruce; Pai, Satyan; Hilario, Eric; Zhang, Boyan; Li, Charlene; Borisov, Oleg; Kelley, Robert F.; Chorny, Ilya; Zhou, Joe Z.; Dill, Ken A.; Swartz, Trevor E.

2014-01-01

For mAbs to be viable therapeutics, they must be formulated to have low viscosity, be chemically stable, and have normal in vivo clearance rates. We explored these properties by observing correlations of up to 60 different antibodies of the IgG1 isotype. Unexpectedly, we observe significant correlations with simple physical properties obtainable from antibody sequences and by molecular dynamics simulations of individual antibody molecules. mAbs viscosities increase strongly with hydrophobicity and charge dipole distribution and decrease with net charge. Fast clearance correlates with high hydrophobicities of certain complementarity determining regions and with high positive or high negative net charge. Chemical degradation from tryptophan oxidation correlates with the average solvent exposure time of tryptophan residues. Aspartic acid isomerization rates can be predicted from solvent exposure and flexibility as determined by molecular dynamics simulations. These studies should aid in more rapid screening and selection of mAb candidates during early discovery. PMID:25512516
Correlated responses for litter traits to six generations of selection for ovulation rate or prenatal survival in French Large White pigs.

PubMed

Rosendo, A; Druet, T; Gogué, J; Canario, L; Bidanel, J P

2007-07-01

Effects of selection for reproductive traits were estimated using data from 3 pig lines derived from the same Large White population base. Two lines were selected for 6 generations on high ovulation rate at puberty (OR line) or high prenatal survival corrected for ovulation rate in the first 2 parities (PS line). The third line was an unselected control line. Genetic parameters for age and BW at puberty (AP and WP); number of piglets born alive, weaned, and nurtured (NBA, NW, and NN, respectively); proportions of stillbirth (PSB) and survival from birth to weaning (PSW); litter and average piglet BW at birth (LWB and AWB), at 21 d (LW21 and AW21), and at weaning (LWW and AWW) were estimated using REML methodology. Heritability estimates were 0.38 +/- 0.03, 0.46 +/- 0.03, 0.16 +/- 0.01, 0.08 +/- 0.01, 0.09 +/- 0.01, 0.04 +/- 0.01, 0.04 +/- 0.02, 0.19 +/- 0.02, 0.10 +/- 0.02, 0.10 +/- 0.02, 0.36 +/- 0.02, 0.27 +/- 0.01, and 0.24 +/- 0.01 for AP, WP, NBA, PSB, NW, NN, PSW, LWB, LW21, LWW, AWB, AW21, and AWW, respectively. The measures of litter size showed strong genetic correlations (r(a) >/= 0.95) and had antagonistic relations with PSB (r(a) = -0.59 to -0.75) and average piglet BW (r(a) = -0.19 to -0.46). They also had strong positive genetic correlations with prenatal survival (r(a) = 0.67 to 0.78) and moderate ones with ovulation rate (r(a) = 0.36 to 0.42). Correlations of litter size with PSW were negative at birth but positive at weaning. The OR and PS lines were negatively related to PSW and average piglet BW. Puberty traits had positive genetic correlations with OR and negative ones with PS. Genetic trends were estimated by computing differences between OR or PS and control lines at each generation using least squares and mixed model methodologies. Average genetic trends were computed by regressing line differences on generation number. Significant (P < 0.05) average genetic trends were obtained in OR and PS lines for AP (respectively, 2.1 +/- 0.9 and 3.2 +/- 1.0 d/generation) and WP (respectively, 2.0 +/- 0.5 and 1.8 +/- 0.5 d/generation) and in the PS line for NBA (0.22 +/- 0.10 piglet/generation). Tendencies (P < 0.10) were also observed for LWB (0.21 +/- 0.12 kg/generation) and AWW (-0.25 +/- 0.14 kg/generation) in the PS line. Selection on components of litter size can be used to improve litter size at birth, but result in undesirable trends for preweaning survival.
Revisiting negative selection algorithms.

PubMed

Ji, Zhou; Dasgupta, Dipankar

2007-01-01

This paper reviews the progress of negative selection algorithms, an anomaly/change detection approach in Artificial Immune Systems (AIS). Following its initial model, we try to identify the fundamental characteristics of this family of algorithms and summarize their diversities. There exist various elements in this method, including data representation, coverage estimate, affinity measure, and matching rules, which are discussed for different variations. The various negative selection algorithms are categorized by different criteria as well. The relationship and possible combinations with other AIS or other machine learning methods are discussed. Prospective development and applicability of negative selection algorithms and their influence on related areas are then speculated based on the discussion.
Strong Solar Wind Dynamic Pressure Pulses during Solar Cycle 23 and Their Impacts on Geosynchronous Magnetic Fields

NASA Astrophysics Data System (ADS)

Zuo, P.

2015-12-01

Solar wind dynamic pressure pulse (DPP) structures, across which the dynamic pressure abruptly changes over timescales from a few seconds to several minutes, are often observed in the near-Earth space environment. In this investigation, we first present a statistical study on the properties of strong dynamic pressure pulses in the solar wind during solar cycle 23. It is found that overwhelming majority of DPPs are associated with the solar wind disturbances including the CME-related flows, the corotating interaction regions, as well as the complex ejecta. The annual variations of the averaged occurrence rate of DPPs are roughly in phase with the solar activities. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears no systematic investigations on the response of GMFs to negative DPPs. Here we also study the decompression/compression effects of very strong negative/positive DPPs on GMFs under northward IMFs. In response to the decompression of strong negative DPPs, GMFs on dayside, near the dawn and dusk on nightside are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of events when GOES is located at the midnight sector, GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that on certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here we found that, a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, being stronger at the noon sector.
Relaxion: A landscape without anthropics

NASA Astrophysics Data System (ADS)

Nelson, Ann; Prescod-Weinstein, Chanda

2017-12-01

The relaxion mechanism provides a potentially elegant solution to the hierarchy problem without resorting to anthropic or other fine-tuning arguments. This mechanism introduces an axion-like field, dubbed the relaxion, whose expectation value determines the electroweak hierarchy as well as the QCD strong C P -violating θ ¯ parameter. During an inflationary period, the Higgs mass squared is selected to be negative and hierarchically small in a theory which is consistent with 't Hooft's technical naturalness criteria. However, in the original model proposed by Graham, Kaplan, and Rajendran [Phys. Rev. Lett. 115, 221801 (2015), 10.1103/PhysRevLett.115.221801], the relaxion does not solve the strong C P problem, and in fact contributes to it, as the coupling of the relaxion to the Higgs field and the introduction of a linear potential for the relaxion produces large strong C P violation. We resolve this tension by considering inflation with a Hubble scale which is above the QCD scale but below the weak scale, and estimating the Hubble temperature dependence of the axion mass. The relaxion potential is thus very different during inflation than it is today. We find that provided the inflationary Hubble scale is between the weak scale and about 3 GeV, the relaxion resolves the hierarchy, strong C P , and dark matter problems in a way that is technically natural.
Expression of myostatin is not altered in lines of poultry exhibiting myofiber hyper- and hypoplasia.

PubMed

Mott, I; Ivarie, R

2002-06-01

Decades of selective breeding have yielded lines of poultry with substantial myofiber hyperplasia, vet little is known about what genes have been altered during the course of selection. Myostatin is a strong negative regulator of muscle mass in mice and cattle and could have been one of many genetic factors contributing to increased myofiber deposition in growth-selected lines of poultry. To test this hypothesis, the sequence and expression patterns of myostatin were analyzed in growth-selected lines of chickens and quail. The sequence of broiler myostatin cDNA, amplified via reverse transcription (RT)-PCR from embryonic muscle RNA, contained no missense mutations in the coding sequence when compared to that of White Leghorn layers, although two silent single nucleotide polymorphisms (SNP) were found. Northern analysis of myostatin transcripts from embryonic pectoralis and quadriceps showed no significant differences in expression levels between broiler and layer muscle RNA. However, levels of myostatin transcripts were greatly reduced in muscles of posthatch chicks compared to embryonic muscle. Myostatin protein was also present in broiler and layer embryonic muscle at similar levels. No significant polymorphisms or differences in RNA expression levels were found in embryonic muscles of divergently selected lines of Japanese quail. These results indicate that intense artificial selection in these growth-selected lines of poultry has neither silenced the expression of myostatin nor created null alleles via mutation in the lines analyzed.
GENOMIC BASIS OF AGING AND LIFE HISTORY EVOLUTION IN DROSOPHILA MELANOGASTER

PubMed Central

Remolina, Silvia C.; Chang, Peter L.; Leips, Jeff; Nuzhdin, Sergey V.; Hughes, Kimberly A.

2015-01-01

Natural diversity in aging and other life history patterns is a hallmark of organismal variation. Related species, populations, and individuals within populations show genetically based variation in life span and other aspects of age-related performance. Population differences are especially informative because these differences can be large relative to within-population variation and because they occur in organisms with otherwise similar genomes. We used experimental evolution to produce populations divergent for life span and late-age fertility and then used deep genome sequencing to detect sequence variants with nucleotide-level resolution. Several genes and genome regions showed strong signatures of selection, and the same regions were implicated in independent comparisons, suggesting that the same alleles were selected in replicate lines. Genes related to oogenesis, immunity, and protein degradation were implicated as important modifiers of late-life performance. Expression profiling and functional annotation narrowed the list of strong candidate genes to 38, most of which are novel candidates for regulating aging. Life span and early-age fecundity were negatively correlated among populations; therefore the alleles we identified also are candidate regulators of a major life-history trade-off. More generally, we argue that hitchhiking mapping can be a powerful tool for uncovering the molecular bases of quantitative genetic variation. PMID:23106705
Habitat selection by breeding waterbirds at ponds with size-structured fish populations

NASA Astrophysics Data System (ADS)

Kloskowski, Janusz; Nieoczym, Marek; Polak, Marcin; Pitucha, Piotr

2010-07-01

Fish may significantly affect habitat use by birds, either as their prey or as competitors. Fish communities are often distinctly size-structured, but the consequences for waterbird assemblages remain poorly understood. We examined the effects of size structure of common carp ( Cyprinus carpio) cohorts together with other biotic and abiotic pond characteristics on the distribution of breeding waterbirds in a seminatural system of monocultured ponds, where three fish age classes were separately stocked. Fish age corresponded to a distinct fish size gradient. Fish age and total biomass, macroinvertebrate and amphibian abundance, and emergent vegetation best explained the differences in bird density between ponds. Abundance of animal prey other than fish (aquatic macroinvertebrates and larval amphibians) decreased with increasing carp age in the ponds. Densities of ducks and smaller grebes were strongly negatively associated with fish age/size gradient. The largest of the grebes, the piscivorous great crested grebe ( Podiceps cristatus), was the only species that preferred ponds with medium-sized fish and was positively associated with total fish biomass. Habitat selection by bitterns and most rallids was instead strongly influenced by the relative amount of emergent vegetation cover in the ponds. Our results show that fish size structure may be an important cue for breeding habitat choice and a factor affording an opportunity for niche diversification in avian communities.
Rapid molecular evolution of human bocavirus revealed by Bayesian coalescent inference.

PubMed

Zehender, Gianguglielmo; De Maddalena, Chiara; Canuti, Marta; Zappa, Alessandra; Amendola, Antonella; Lai, Alessia; Galli, Massimo; Tanzi, Elisabetta

2010-03-01

Human bocavirus (HBoV) is a linear single-stranded DNA virus belonging to the Parvoviridae family that has recently been isolated from the upper respiratory tract of children with acute respiratory infection. All of the strains observed so far segregate into two genotypes (1 and 2) with a low level of polymorphism. Given the recent description of the infection and the lack of epidemiological and molecular data, we estimated the virus's rates of molecular evolution and population dynamics. A dataset of forty-nine dated VP2 sequences, including also eight new isolates obtained from pharyngeal swabs of Italian patients with acute respiratory tract infections, was submitted to phylogenetic analysis. The model parameters, evolutionary rates and population dynamics were co-estimated using a Bayesian Markov Chain Monte Carlo approach, and site-specific positive and negative selection was also investigated. Recombination was investigated by seven different methods and one suspected recombinant strain was excluded from further analysis. The estimated mean evolutionary rate of HBoV was 8.6x10(-4)subs/site/year, and that of the 1st+2nd codon positions was more than 15 times less than that of the 3rd codon position. Viral population dynamics analysis revealed that the two known genotypes diverged recently (mean tMRCA: 24 years), and that the epidemic due to HBoV genotype 2 grew exponentially at a rate of 1.01year(-1). Selection analysis of the partial VP2 showed that 8.5% of sites were under significant negative pressure and the absence of positive selection. Our results show that, like other parvoviruses, HBoV is characterised by a rapid evolution. The low level of polymorphism is probably due to a relatively recent divergence between the circulating genotypes and strong purifying selection acting on viral antigens.
Selection Shapes Transcriptional Logic and Regulatory Specialization in Genetic Networks

PubMed Central

Fogelmark, Karl; Peterson, Carsten; Troein, Carl

2016-01-01

Background Living organisms need to regulate their gene expression in response to environmental signals and internal cues. This is a computational task where genes act as logic gates that connect to form transcriptional networks, which are shaped at all scales by evolution. Large-scale mutations such as gene duplications and deletions add and remove network components, whereas smaller mutations alter the connections between them. Selection determines what mutations are accepted, but its importance for shaping the resulting networks has been debated. Methodology To investigate the effects of selection in the shaping of transcriptional networks, we derive transcriptional logic from a combinatorially powerful yet tractable model of the binding between DNA and transcription factors. By evolving the resulting networks based on their ability to function as either a simple decision system or a circadian clock, we obtain information on the regulation and logic rules encoded in functional transcriptional networks. Comparisons are made between networks evolved for different functions, as well as with structurally equivalent but non-functional (neutrally evolved) networks, and predictions are validated against the transcriptional network of E. coli. Principal Findings We find that the logic rules governing gene expression depend on the function performed by the network. Unlike the decision systems, the circadian clocks show strong cooperative binding and negative regulation, which achieves tight temporal control of gene expression. Furthermore, we find that transcription factors act preferentially as either activators or repressors, both when binding multiple sites for a single target gene and globally in the transcriptional networks. This separation into positive and negative regulators requires gene duplications, which highlights the interplay between mutation and selection in shaping the transcriptional networks. PMID:26927540
Selection and Inhibition in Infancy: Evidence from the Spatial Negative Priming Paradigm

ERIC Educational Resources Information Center

Amso, D.; Johnson, S.P.

2005-01-01

We used a spatial negative priming (SNP) paradigm to examine visual selective attention in infants and adults using eye movements as the motor selection measure. In SNP, when a previously ignored location becomes the target to be selected, responses to it are impaired, providing a measure of inhibitory selection. Each trial consisted of a prime…

Active Construction of Profession-Related Events: The Priming Effect among Pre-service Teachers with Different Professional Identity

PubMed Central

Wang, Xin-qiang; Zhu, Jun-cheng; Liu, Lu; Chen, Xiang-yu; Huo, Jun-yu

2018-01-01

Pre-service teachers with different professional identity may actively construct different subjective profession-related events based on the same objective profession-related events. To explore the priming effect among pre-service teachers with different professional identity, this study examined the effect of positive, negative, or neutral priming sentences in an individualized narration of profession-related events through a priming paradigm. Forty-two female volunteers were asked to complete positive, negative, and neutral priming sentences describing profession-related events. The results showed that, relative to those with weak professional identity, participants with strong professional identity generated a higher number of positive items when primed with different stimuli and displayed greater positive priming bias for positive and neutral stimuli. In addition, relative to those with strong professional identity, participants with weak professional identity generated a higher number of neutral and negative items when primed with positive and negative stimuli, respectively, and displayed greater negative priming bias toward negative stimuli. These results indicate that pre-service teachers with strong professional identity were likely to have established positive self-schemas involving profession-related events, which facilitated active, positive construction of such events. PMID:29535667
Active Construction of Profession-Related Events: The Priming Effect among Pre-service Teachers with Different Professional Identity.

PubMed

Wang, Xin-Qiang; Zhu, Jun-Cheng; Liu, Lu; Chen, Xiang-Yu; Huo, Jun-Yu

2018-01-01

Pre-service teachers with different professional identity may actively construct different subjective profession-related events based on the same objective profession-related events. To explore the priming effect among pre-service teachers with different professional identity, this study examined the effect of positive, negative, or neutral priming sentences in an individualized narration of profession-related events through a priming paradigm. Forty-two female volunteers were asked to complete positive, negative, and neutral priming sentences describing profession-related events. The results showed that, relative to those with weak professional identity, participants with strong professional identity generated a higher number of positive items when primed with different stimuli and displayed greater positive priming bias for positive and neutral stimuli. In addition, relative to those with strong professional identity, participants with weak professional identity generated a higher number of neutral and negative items when primed with positive and negative stimuli, respectively, and displayed greater negative priming bias toward negative stimuli. These results indicate that pre-service teachers with strong professional identity were likely to have established positive self-schemas involving profession-related events, which facilitated active, positive construction of such events.
The Chandra Strong Lens Sample: Revealing Baryonic Physics In Strong Lensing Selected Clusters

NASA Astrophysics Data System (ADS)

Bayliss, Matthew

2017-08-01

We propose for Chandra imaging of the hot intra-cluster gas in a unique new sample of 29 galaxy clusters selected purely on their strong gravitational lensing signatures. This will be the first program targeting a purely strong lensing selected cluster sample, enabling new comparisons between the ICM properties and scaling relations of strong lensing and mass/ICM selected cluster samples. Chandra imaging, combined with high precision strong lens models, ensures powerful constraints on the distribution and state of matter in the cluster cores. This represents a novel angle from which we can address the role played by baryonic physics |*| the infamous |*|gastrophysics|*| in shaping the cores of massive clusters, and opens up an exciting new galaxy cluster discovery space with Chandra.
The Chandra Strong Lens Sample: Revealing Baryonic Physics In Strong Lensing Selected Clusters

NASA Astrophysics Data System (ADS)

Bayliss, Matthew

2017-09-01

We propose for Chandra imaging of the hot intra-cluster gas in a unique new sample of 29 galaxy clusters selected purely on their strong gravitational lensing signatures. This will be the first program targeting a purely strong lensing selected cluster sample, enabling new comparisons between the ICM properties and scaling relations of strong lensing and mass/ICM selected cluster samples. Chandra imaging, combined with high precision strong lens models, ensures powerful constraints on the distribution and state of matter in the cluster cores. This represents a novel angle from which we can address the role played by baryonic physics -- the infamous ``gastrophysics''-- in shaping the cores of massive clusters, and opens up an exciting new galaxy cluster discovery space with Chandra.
Situation Selection and Modification for Emotion Regulation in Younger and Older Adults.

PubMed

Livingstone, Kimberly M; Isaacowitz, Derek M

2015-11-01

This research investigated age differences in use and effectiveness of situation selection and situation modification for emotion regulation. Socioemotional selectivity theory suggests stronger emotional well-being goals in older age; emotion regulation may support this goal. Younger and older adults assigned to an emotion regulation or "just view" condition first freely chose to engage with negative, neutral, or positive material (situation selection), then chose to view or skip negative and positive material (situation modification), rating affect after each experience. In both tasks, older adults in both goal conditions demonstrated pro-hedonic emotion regulation, spending less time with negative material compared to younger adults. Younger adults in the regulate condition also engaged in pro-hedonic situation selection, but not modification. Whereas situation selection was related to affect, modification of negative material was not. This research supports more frequent pro-hedonic motivation in older age, as well as age differences in use of early-stage emotion regulation.
Solid-phase synthesis and insights into structure-activity relationships of safinamide analogues as potent and selective inhibitors of type B monoamine oxidase.

PubMed

Leonetti, Francesco; Capaldi, Carmelida; Pisani, Leonardo; Nicolotti, Orazio; Muncipinto, Giovanni; Stefanachi, Angela; Cellamare, Saverio; Caccia, Carla; Carotti, Angelo

2007-10-04

Safinamide, (S)-N2-{4-[(3-fluorobenzyl)oxy]benzyl}alaninamide methanesulfonate, which is in phase III clinical trials as an anti-Parkinson drug, and a library of alkanamidic analogues were prepared through an expeditious solid-phase synthesis and evaluated for their monoamine oxidase B (MAO-B) and monoamine oxidase A (MAO-A) inhibitory activity and selectivity. (S)-3-Chlorobenzyloxyalaninamide (8) and (S)-3-chlorobenzyloxyserinamide (13) derivatives proved to be more potent MAO-B inhibitors than safinamide (IC50 = 33 and 43 nM, respectively, vs 98 nM) but with a lower MAO-B selectivity (SI = 3455 and 1967, respectively, vs 5918). The highest MAO-B inhibitory potency (IC50 = 17 nM) and a good selectivity (SI = 2941) were displayed by (R)-21, a tetrahydroisoquinoline analogue of safinamide. Structure-affinity relationships and docking simulations pointed out strong negative steric effects of alpha-aminoamide side chains and para substituents of the benzyloxy groups and favorable hydrophobic interactions of meta substituents. The significantly diverse MAO-B affinities of a number of R and S alpha-aminoamide enantiomers, including the two rigid analogues (21) of safinamide, indicated likely enantioselective interactions at the enzymatic binding sites.
Bodily attractiveness and egalitarianism are negatively related in males.

PubMed

Price, Michael E; Brown, Stuart; Dukes, Amber; Kang, Jinsheng

2015-02-09

Ancestrally, relatively attractive individuals and relatively formidable males may have had reduced incentives to be egalitarian (i.e., to act in accordance with norms promoting social equality). If selection calibrated one's egalitarianism to one's attractiveness/formidability, then such people may exhibit reduced egalitarianism ("observed egalitarianism") and be perceived by others as less egalitarian ("perceived egalitarianism") in modern environments. To investigate, we created 3D body models of 125 participants to use both as a source of anthropometric measurements and as stimuli to obtain ratings of bodily attractiveness and perceived egalitarianism. We also measured observed egalitarianism (via an economic "dictator" game) and indices of political egalitarianism (preference for socialism over capitalism) and "equity sensitivity." Results indicated higher egalitarianism levels in women than in men, and moderate-to-strong negative relationships between (a) attractiveness and observed egalitarianism among men, (b) attractiveness and perceived egalitarianism among both sexes, and (c) formidability and perceived egalitarianism among men. We did not find support for two previously-reported findings: that observed egalitarianism and formidability are negatively related in men, and that wealth and formidability interact to explain variance in male egalitarianism. However, this lack of support may have been due to differences in variable measurement between our study and previous studies.
Impact of elicited mood on movement expressivity during a fitness task.

PubMed

Giraud, Tom; Focone, Florian; Isableu, Brice; Martin, Jean-Claude; Demulier, Virginie

2016-10-01

The purpose of the present study was to evaluate the impact of four mood conditions (control, positive, negative, aroused) on movement expressivity during a fitness task. Motion capture data from twenty individuals were recorded as they performed a predefined motion sequence. Moods were elicited using task-specific scenarii to keep a valid context. Movement qualities inspired by Effort-Shape framework (Laban & Ullmann, 1971) were computed (i.e., Impulsiveness, Energy, Directness, Jerkiness and Expansiveness). A reduced number of computed features from each movement quality was selected via Principal Component Analyses. Analyses of variance and Generalized Linear Mixed Models were used to identify movement characteristics discriminating the four mood conditions. The aroused mood condition was strongly associated with increased mean Energy compared to the three other conditions. The positive and negative mood conditions showed more subtle differences interpreted as a result of their moderate activation level. Positive mood was associated with more impulsive movements and negative mood was associated with more tense movements (i.e., reduced variability and increased Jerkiness). Findings evidence the key role of movement qualities in capturing motion signatures of moods and highlight the importance of task context in their interpretations. Copyright © 2016 Elsevier B.V. All rights reserved.
Discrimination of selected species of pathogenic bacteria using near-infrared Raman spectroscopy and principal components analysis

NASA Astrophysics Data System (ADS)

de Siqueira e Oliveira, Fernanda SantAna; Giana, Hector Enrique; Silveira, Landulfo

2012-10-01

A method, based on Raman spectroscopy, for identification of different microorganisms involved in bacterial urinary tract infections has been proposed. Spectra were collected from different bacterial colonies (Gram-negative: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Enterobacter cloacae, and Gram-positive: Staphylococcus aureus and Enterococcus spp.), grown on culture medium (agar), using a Raman spectrometer with a fiber Raman probe (830 nm). Colonies were scraped from the agar surface and placed on an aluminum foil for Raman measurements. After preprocessing, spectra were submitted to a principal component analysis and Mahalanobis distance (PCA/MD) discrimination algorithm. We found that the mean Raman spectra of different bacterial species show similar bands, and S. aureus was well characterized by strong bands related to carotenoids. PCA/MD could discriminate Gram-positive bacteria with sensitivity and specificity of 100% and Gram-negative bacteria with sensitivity ranging from 58 to 88% and specificity ranging from 87% to 99%.
Nestin expression in neuroepithelial tumors.

PubMed

Schiffer, Davide; Manazza, Andrea; Tamagno, Ilaria

2006-05-29

Nestin is a marker of early stages of neurocytogenesis. It has been studied in 50 neuroepithelial tumors, mostly gliomas of different malignancy grades, by immunohistochemistry, immunofluorescence, immunoblotting, and confocal microscopy and compared with GFAP and Vimentin. As an early marker of differentiation, Nestin is almost not expressed in diffuse astrocytomas, variably expressed in anaplastic astrocytomas and strongly and irregularly expressed in glioblastomas. Negative in oligodendrogliomas, it stains ependymomas and shows a gradient of expression in pilocytic astrocytomas. In glioblastomas, Nestin distribution does not completely correspond to that of GFAP and Vimentin with which its expression varies in tumor cells in a complementary way, as confirmed by confocal microscopy. Tumor cells can thus either derive from or differentiate toward the neurocytogenetic stages. Hypothetically, they could be put in relation with radial glia where during embriogenesis the three antigens are successively expressed. Completely negative cells of invasive or recurrent glioblastomas may represent malignant selected clones after accumulation of mutations or early stem cells not expressing antigens.
Antifouling activity in some benthic Antarctic invertebrates by "in situ" experiments at Deception Island, Antarctica.

PubMed

Angulo-Preckler, Carlos; Cid, Cristina; Oliva, Francesc; Avila, Conxita

2015-04-01

Competition for space is a remarkable ecological force, comparable to predation, producing a strong selective pressure on benthic invertebrates. Some invertebrates, thus, possess antimicrobial compounds to reduce surface bacterial growth. Antimicrobial inhibition is the first step in avoiding being overgrown by other organisms, which may have a negative impact in feeding, respiration, reproduction … The in situ inhibition of bacterial biofilm was used here as an indicator of antifouling activity by testing hydrophilic extracts of twelve Antarctic invertebrates. Using two different approaches (genetics and confocal techniques) different levels of activity were found in the tested organisms. In fact, differences within body parts of the studied organisms were determined, in agreement with the Optimal Defense Theory. Eight out of 15 extracts tested had negative effects on fouling after 28 days submerged in Antarctic waters. Thus, although chemical defenses may be quite species-specific in their ecological roles, these results suggest that different chemical strategies exist to deal with space competition. Copyright © 2015 Elsevier Ltd. All rights reserved.
The tunnel magnetoresistance in chains of quantum dots weakly coupled to external leads.

PubMed

Weymann, Ireneusz

2010-01-13

We analyze numerically the spin-dependent transport through coherent chains of three coupled quantum dots weakly connected to external magnetic leads. In particular, using the diagrammatic technique on the Keldysh contour, we calculate the conductance, shot noise and tunnel magnetoresistance (TMR) in the sequential and cotunneling regimes. We show that transport characteristics greatly depend on the strength of the interdot Coulomb correlations, which determines the spatial distribution of the electron wavefunction in the chain. When the correlations are relatively strong, depending on the transport regime, we find both negative TMR as well as TMR enhanced above the Julliere value, accompanied with negative differential conductance (NDC) and super-Poissonian shot noise. This nontrivial behavior of tunnel magnetoresistance is associated with selection rules that govern tunneling processes and various high-spin states of the chain that are relevant for transport. For weak interdot correlations, on the other hand, the TMR is always positive and not larger than the Julliere TMR, although super-Poissonian shot noise and NDC can still be observed.
Emotional connotations of words related to authority and community.

PubMed

Schauenburg, Gesche; Ambrasat, Jens; Schröder, Tobias; von Scheve, Christian; Conrad, Markus

2015-09-01

We present a database of 858 German words from the semantic fields of authority and community, which represent core dimensions of human sociality. The words were selected on the basis of co-occurrence profiles of representative keywords for these semantic fields. All words were rated along five dimensions, each measured by a bipolar semantic-differential scale: Besides the classic dimensions of affective meaning (valence, arousal, and potency), we collected ratings of authority and community with newly developed scales. The results from cluster, correlational, and multiple regression analyses on the rating data suggest a robust negativity bias for authority valuation among German raters recruited via university mailing lists, whereas community ratings appear to be rather unrelated to the well-established affective dimensions. Furthermore, our data involve a strong overall negative correlation-rather than the classical U-shaped distribution-between valence and arousal for socially relevant concepts. Our database provides a valuable resource for research questions at the intersection of cognitive neuroscience and social psychology. It can be downloaded as supplemental materials with this article.
Age and the experience of strong self-conscious emotion.

PubMed

Henry, Julie D; von Hippel, William; Nangle, Matthew R; Waters, Michele

2018-04-01

It remains unclear whether there are age-related changes in the experience of strong self-conscious emotion, such as shame, guilt, pride and embarrassment. Because shame and guilt figure prominently in the aetiology of depressive symptoms and other mental health problems, a better understanding of how age affects the strong experience of these two negative self-conscious emotions is of particular importance. Thirty younger, 30 middle-aged and 30 older adults were compared on standardised cognitive assessments, in addition to an interview-based measure that assessed whether there are age differences in the likelihood of strongly experiencing four different types of self-conscious emotion within the past five years (shame, guilt, embarrassment and pride). The three groups did not differ in their likelihood of reporting an event that strongly elicited the positive self-conscious emotion of pride. However, older adults were more likely to report sources of pride that were other (as opposed to self) focused. Older adults were also less likely to report experiencing events that elicited all three negative self-conscious emotions, in particular, shame. Strong negative self-conscious emotion, and in particular shame, appears to be experienced less by older than younger adults.
Reactions to graphic health warnings in the United States.

PubMed

Nonnemaker, James M; Choiniere, Conrad J; Farrelly, Matthew C; Kamyab, Kian; Davis, Kevin C

2015-02-01

This study reports consumer reactions to the graphic health warnings selected by the Food and Drug Administration to be placed on cigarette packs in the United States. We recruited three sets of respondents for an experimental study from a national opt-in e-mail list sample: (i) current smokers aged 25 or older, (ii) young adult smokers aged 18-24 and (iii) youth aged 13-17 who are current smokers or who may be susceptible to initiation of smoking. Participants were randomly assigned to be exposed to a pack of cigarettes with one of nine graphic health warnings or with a text-only warning statement. All three age groups had overall strong negative emotional (ß = 4.7, P < 0.001 for adults; ß = 4.6, P < 0.001 for young adults and ß = 4.0, P < 0.001 for youth) and cognitive (ß = 2.4, P < 0.001 for adults; ß = 3.0, P < 0.001 for young adults and ß = 4.6, P < 0.001 for youth) reactions to the proposed labels. The strong negative emotional and cognitive reactions following a single exposure to the graphic health warnings suggest that, with repeated exposures over time, graphic health warnings may influence smokers' beliefs, intentions and behaviors. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.
Validation of sentinel lymph node biopsy in breast cancer women N1-N2 with complete axillary response after neoadjuvant chemotherapy. Multicentre study in Tarragona.

PubMed

Carrera, D; de la Flor, M; Galera, J; Amillano, K; Gomez, M; Izquierdo, V; Aguilar, E; López, S; Martínez, M; Martínez, S; Serra, J M; Pérez, M; Martin, L

2016-01-01

The aim of our study was to evaluate sentinel lymph node biopsy as a diagnostic test for assessing the presence of residual metastatic axillary lymph nodes after neoadjuvant chemotherapy, replacing the need for a lymphadenectomy in negative selective lymph node biopsy patients. A multicentre, diagnostic validation study was conducted in the province of Tarragona, on women with T1-T3, N1-N2 breast cancer, who presented with a complete axillary response after neoadjuvant chemotherapy. Study procedures consisted of performing an selective lymph node biopsy followed by lymphadenectomy. A total of 53 women were included in the study. Surgical detection rate was 90.5% (no sentinel node found in 5 patients). Histopathological analysis of the lymphadenectomy showed complete disease regression of axillary nodes in 35.4% (17/48) of the patients, and residual axillary node involvement in 64.6% (31/48) of them. In lymphadenectomy positive patients, 28 had a positive selective lymph node biopsy (true positive), while 3 had a negative selective lymph node biopsy (false negative). Of the 28 true selective lymph node biopsy positives, the sentinel node was the only positive node in 10 cases. All lymphadenectomy negative cases were selective lymph node biopsy negative. These data yield a sensitivity of 93.5%, a false negative rate of 9.7%, and a global test efficiency of 93.7%. Selective lymph node biopsy after chemotherapy in patients with a complete axillary response provides valid and reliable information regarding axillary status after neoadjuvant treatment, and might prevent lymphadenectomy in cases with negative selective lymph node biopsy. Copyright © 2016 Elsevier España, S.L.U. and SEMNIM. All rights reserved.
Dynamic Convergent Evolution Drives the Passage Adaptation across 48 Years' History of H3N2 Influenza Evolution.

PubMed

Chen, Hui; Deng, Qiang; Ng, Sock Hoon; Lee, Raphael Tze Chuen; Maurer-Stroh, Sebastian; Zhai, Weiwei

2016-12-01

Influenza viruses are often propagated in a diverse set of culturing media and additional substitutions known as passage adaptation can cause extra evolution in the target strain, leading to ineffective vaccines. Using 25,482 H3N2 HA1 sequences curated from Global Initiative on Sharing All Influenza Data and National Center for Biotechnology Information databases, we found that passage adaptation is a very dynamic process that changes over time and evolves in a seesaw like pattern. After crossing the species boundary from bird to human in 1968, the influenza H3N2 virus evolves to be better adapted to the human environment and passaging them in embryonated eggs (i.e., an avian environment) leads to increasingly stronger positive selection. On the contrary, passage adaptation to the mammalian cell lines changes from positive selection to negative selection. Using two statistical tests, we identified 19 codon positions around the receptor binding domain strongly contributing to passage adaptation in the embryonated egg. These sites show strong convergent evolution and overlap extensively with positively selected sites identified in humans, suggesting that passage adaptation can confound many of the earlier studies on influenza evolution. Interestingly, passage adaptation in recent years seems to target a few codon positions in antigenic surface epitopes, which makes it difficult to produce antigenically unaltered vaccines using embryonic eggs. Our study outlines another interesting scenario whereby both convergent and adaptive evolution are working in synchrony driving viral adaptation. Future studies from sequence analysis to vaccine production need to take careful consideration of passage adaptation. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Thermodynamic Basis of Selectivity in the Interactions of Tissue Inhibitors of Metalloproteinases N-domains with Matrix Metalloproteinases-1, -3, and -14*

PubMed Central

Zou, Haiyin; Wu, Ying

2016-01-01

The four tissue inhibitors of metalloproteinases (TIMPs) are potent inhibitors of the many matrixins (MMPs), except that TIMP1 weakly inhibits some MMPs, including MMP14. The broad-spectrum inhibition of MMPs by TIMPs and their N-domains (NTIMPs) is consistent with the previous isothermal titration calorimetric finding that their interactions are entropy-driven but differ in contributions from solvent and conformational entropy (ΔSsolv, ΔSconf), estimated using heat capacity changes (ΔCp). Selective engineered NTIMPs have potential applications for treating MMP-related diseases, including cancer and cardiomyopathy. Here we report isothermal titration calorimetric studies of the effects of selectivity-modifying mutations in NTIMP1 and NTIMP2 on the thermodynamics of their interactions with MMP1, MMP3, and MMP14. The weak inhibition of MMP14 by NTIMP1 reflects a large conformational entropy penalty for binding. The T98L mutation, peripheral to the NTIMP1 reactive site, enhances binding by increasing ΔSsolv but also reduces ΔSconf. However, the same mutation increases NTIMP1 binding to MMP3 in an interaction that has an unusual positive ΔCp. This indicates a decrease in solvent entropy compensated by increased conformational entropy, possibly reflecting interactions involving alternative conformers. The NTIMP2 mutant, S2D/S4A is a selective MMP1 inhibitor through electrostatic effects of a unique MMP-1 arginine. Asp-2 increases reactive site polarity, reducing ΔCp, but increases conformational entropy to maintain strong binding to MMP1. There is a strong negative correlation between ΔSsolv and ΔSconf for all characterized interactions, but the data for each MMP have characteristic ranges, reflecting intrinsic differences in the structures and dynamics of their free and inhibitor-bound forms. PMID:27033700
MHC II-β chain gene expression studies define the regional organization of the thymus in the developing bony fish Dicentrarchus labrax (L.).

PubMed

Picchietti, S; Abelli, L; Guerra, L; Randelli, E; Proietti Serafini, F; Belardinelli, M C; Buonocore, F; Bernini, C; Fausto, A M; Scapigliati, G

2015-02-01

MHC II-β chain gene transcripts were quantified by real-time PCR and localised by in situ hybridization in the developing thymus of the teleost Dicentrarchus labrax, regarding the specialization of the thymic compartments. MHC II-β expression significantly rose when the first lymphoid colonization of the thymus occurred, thereafter increased further when the organ progressively developed cortex and medulla regions. The evolving patterns of MHC II-β expression provided anatomical insights into some mechanisms of thymocyte selection. Among the stromal cells transcribing MHC II-β, scattered cortical epithelial cells appeared likely involved in the positive selection, while those abundant in the cortico-medullary border and medulla in the negative selection. These latter most represent dendritic cells, based on typical localization and phenotype. These findings provide further proofs that efficient mechanisms leading to maturation of naïve T cells are operative in teleosts, strongly reminiscent of the models conserved in more evolved gnathostomes. Copyright © 2014 Elsevier Ltd. All rights reserved.
Children Do Show Negative Priming: Further Evidence for Early Development of an Intact Selective Control Mechanism

ERIC Educational Resources Information Center

Frings, Christian; Feix, Silke; Rothig, Ulrike; Bruser, Charlotte; Junge, Miriam

2007-01-01

Reactions to stimuli that were shortly before presented as distractors are usually slowed down; this phenomenon is known as negative priming. Negative priming is an accepted index for tapping into selective control mechanisms. Although this effect is well established for adults, it has been claimed that children do not show negative priming.…

Cationic cell-penetrating peptide binds to planar lipid bilayers containing negatively charged lipids but does not induce conductive pores.

PubMed

Gurnev, Philip A; Yang, Sung-Tae; Melikov, Kamran C; Chernomordik, Leonid V; Bezrukov, Sergey M

2013-05-07

Using a cation-selective gramicidin A channel as a sensor of the membrane surface charge, we studied interactions of oligoarginine peptide R9C, a prototype cationic cell-penetrating peptide (CPP), with planar lipid membranes. We have found that R9C sorption to the membrane depends strongly on its lipid composition from virtually nonexistent for membranes made of uncharged lipids to very pronounced for membranes containing negatively charged lipids, with charge overcompensation at R9C concentrations exceeding 1 μM. The sorption was reversible as it was removed by addition of polyanionic dextran sulfate to the membrane bathing solution. No membrane poration activity of R9C (as would be manifested by increased bilayer conductance) was detected in the charged or neutral membranes, including those with asymmetric negative/neutral and negative/positive lipid leaflets. We conclude that interaction of R9C with planar lipid bilayers does not involve pore formation in all studied lipid combinations up to 20 μM peptide concentration. However, R9C induces leakage of negatively charged but not neutral liposomes in a process that involves lipid mixing between liposomes. Our findings suggest that direct traversing of CPPs through the uncharged outer leaflet of the plasma membrane bilayer is unlikely and that permeabilization necessarily involves both anionic lipids and CPP-dependent fusion between opposing membranes. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.
And the Last Shall Be First: Heterochrony and Compensatory Marine Growth in Sea Trout (Salmo trutta)

PubMed Central

Marco-Rius, Francisco; Caballero, Pablo; Morán, Paloma; Garcia de Leaniz, Carlos

2012-01-01

Early juvenile growth is a good indicator of growth later in life in many species because larger than average juveniles tend to have a competitive advantage. However, for migratory species the relationship between juvenile and adult growth remains obscure. We used scale analysis to reconstruct growth trajectories of migratory sea trout (Salmo trutta) from six neighbouring populations, and compared the size individuals attained in freshwater (before migration) with their subsequent growth at sea (after migration). We also calculated the coefficient of variation (CV) to examine how much body size varied across populations and life stages. Specifically, we tested the hypothesis that the CV on body size would differ between freshwater and marine environment, perhaps reflecting different trade-offs during ontogeny. Neighbouring sea trout populations differed significantly in time spent at sea and in age-adjusted size of returning adults, but not on size of seaward migration, which was surprisingly uniform and may be indicative of strong selection pressures. The CV on body size decreased significantly over time and was highest during the first 8 months of life (when juvenile mortality is highest) and lowest during the marine phase. Size attained in freshwater was negatively related to growth during the first marine growing season, suggesting the existence of compensatory growth, whereby individuals that grow poorly in freshwater are able to catch up later at sea. Analysis of 61 datasets indicates that negative or no associations between pre- and post-migratory growth are common amongst migratory salmonids. We suggest that despite a widespread selective advantage of large body size in freshwater, freshwater growth is a poor predictor of final body size amongst migratory fish because selection may favour growth heterochrony during transitions to a novel environment, and marine compensatory growth may negate any initial size advantage acquired in freshwater. PMID:23049680
Expanding the potential of NAI-107 for treating serious ESKAPE pathogens: synergistic combinations against Gram-negatives and bactericidal activity against non-dividing cells

PubMed Central

Brunati, Cristina; Thomsen, Thomas T; Gaspari, Eleonora; Maffioli, Sonia; Sosio, Margherita; Jabes, Daniela; Løbner-Olesen, Anders; Donadio, Stefano

2018-01-01

Abstract Objectives To characterize NAI-107 and related lantibiotics for their in vitro activity against Gram-negative pathogens, alone or in combination with polymyxin, and against non-dividing cells or biofilms of Staphylococcus aureus. NAI-107 was also evaluated for its propensity to select or induce self-resistance in Gram-positive bacteria. Methods We used MIC determinations and chequerboard experiments to establish the antibacterial activity of the examined compounds against target microorganisms. Time–kill assays were used to evaluate killing of exponential and stationary-phase cells. The effects on biofilms (growth inhibition and biofilm eradication) were evaluated using biofilm-coated pegs. The frequency of spontaneous resistant mutants was evaluated by either direct plating or by continuous sub-culturing at 0.5 × MIC levels, followed by population analysis profiles. Results The results showed that NAI-107 and its brominated variant are highly active against Neisseria gonorrhoeae and some other fastidious Gram-negative pathogens. Furthermore, all compounds strongly synergized with polymyxin against Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, and showed bactericidal activity. Surprisingly, NAI-107 alone was bactericidal against non-dividing A. baumannii cells. Against S. aureus, NAI-107 and related lantibiotics showed strong bactericidal activity against dividing and non-dividing cells. Activity was also observed against S. aureus biofilms. As expected for a lipid II binder, no significant resistance to NAI-107 was observed by direct plating or serial passages. Conclusions Overall, the results of the current work, along with previously published results on the efficacy of NAI-107 in experimental models of infection, indicate that this lantibiotic represents a promising option in addressing the serious threat of antibiotic resistance. PMID:29092042
Expanding the potential of NAI-107 for treating serious ESKAPE pathogens: synergistic combinations against Gram-negatives and bactericidal activity against non-dividing cells.

PubMed

Brunati, Cristina; Thomsen, Thomas T; Gaspari, Eleonora; Maffioli, Sonia; Sosio, Margherita; Jabes, Daniela; Løbner-Olesen, Anders; Donadio, Stefano

2018-02-01

To characterize NAI-107 and related lantibiotics for their in vitro activity against Gram-negative pathogens, alone or in combination with polymyxin, and against non-dividing cells or biofilms of Staphylococcus aureus. NAI-107 was also evaluated for its propensity to select or induce self-resistance in Gram-positive bacteria. We used MIC determinations and chequerboard experiments to establish the antibacterial activity of the examined compounds against target microorganisms. Time-kill assays were used to evaluate killing of exponential and stationary-phase cells. The effects on biofilms (growth inhibition and biofilm eradication) were evaluated using biofilm-coated pegs. The frequency of spontaneous resistant mutants was evaluated by either direct plating or by continuous sub-culturing at 0.5 × MIC levels, followed by population analysis profiles. The results showed that NAI-107 and its brominated variant are highly active against Neisseria gonorrhoeae and some other fastidious Gram-negative pathogens. Furthermore, all compounds strongly synergized with polymyxin against Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, and showed bactericidal activity. Surprisingly, NAI-107 alone was bactericidal against non-dividing A. baumannii cells. Against S. aureus, NAI-107 and related lantibiotics showed strong bactericidal activity against dividing and non-dividing cells. Activity was also observed against S. aureus biofilms. As expected for a lipid II binder, no significant resistance to NAI-107 was observed by direct plating or serial passages. Overall, the results of the current work, along with previously published results on the efficacy of NAI-107 in experimental models of infection, indicate that this lantibiotic represents a promising option in addressing the serious threat of antibiotic resistance. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy.
Roadmap on optical metamaterials

NASA Astrophysics Data System (ADS)

Urbas, Augustine M.; Jacob, Zubin; Dal Negro, Luca; Engheta, Nader; Boardman, A. D.; Egan, P.; Khanikaev, Alexander B.; Menon, Vinod; Ferrera, Marcello; Kinsey, Nathaniel; DeVault, Clayton; Kim, Jongbum; Shalaev, Vladimir; Boltasseva, Alexandra; Valentine, Jason; Pfeiffer, Carl; Grbic, Anthony; Narimanov, Evgenii; Zhu, Linxiao; Fan, Shanhui; Alù, Andrea; Poutrina, Ekaterina; Litchinitser, Natalia M.; Noginov, Mikhail A.; MacDonald, Kevin F.; Plum, Eric; Liu, Xiaoying; Nealey, Paul F.; Kagan, Cherie R.; Murray, Christopher B.; Pawlak, Dorota A.; Smolyaninov, Igor I.; Smolyaninova, Vera N.; Chanda, Debashis

2016-09-01

Optical metamaterials have redefined how we understand light in notable ways: from strong response to optical magnetic fields, negative refraction, fast and slow light propagation in zero index and trapping structures, to flat, thin and perfect lenses. Many rules of thumb regarding optics, such as μ = 1, now have an exception, and basic formulas, such as the Fresnel equations, have been expanded. The field of metamaterials has developed strongly over the past two decades. Leveraging structured materials systems to generate tailored response to a stimulus, it has grown to encompass research in optics, electromagnetics, acoustics and, increasingly, novel hybrid material responses. This roadmap is an effort to present emerging fronts in areas of optical metamaterials that could contribute and apply to other research communities. By anchoring each contribution in current work and prospectively discussing future potential and directions, the authors are translating the work of the field in selected areas to a wider community and offering an incentive for outside researchers to engage our community where solid links do not already exist.
Experimental assessment of the effects of gastrointestinal parasites on offspring quality in chinstrap penguins (Pygoscelis antarctica).

PubMed

Palacios, M J; Valera, F; Barbosa, A

2012-05-01

Parasites reduce host fitness and consequently impose strong selection pressures on their hosts. It has been hypothesized that parasites are scarcer and their overall effect on hosts is weaker at higher latitudes. Although Antarctic birds have relatively low numbers of parasites, their effect on host fitness has rarely been investigated. The effect of helminth parasitism on growth rate was experimentally studied in chinstrap penguin (Pygoscelis antarctica) nestlings. In a total of 22 two-nestling broods, 1 nestling was treated with anthelminthics (for cestodes and nematodes) while its sibling was left as a control. Increased growth rate was predicted in de-wormed nestlings compared to their siblings. As expected, 15 days after treatment, the experimental nestlings had increased body mass more than their siblings. These results show a non-negligible negative effect of helminth parasites on nestling body condition that would presumably affect future survival and thus fitness, and it has been suggested there is a strong relationship between body mass and mortality in chinstrap penguins.
MARRIAGE AND MEN’S WEALTH ACCUMULATION IN THE UNITED STATES, 1860-1870

PubMed Central

HONG, SOK CHUL

2013-01-01

This paper explores how changes in marital status affected men’s wealth accumulation in mid-nineteenth-century America, using a longitudinal sample of Union Army veterans linked to the 1860 and 1870 census manuscript schedules. Controlling for the endogeneity of wealth and marital selection, this paper provides strong evidence that marriage had positive effects on men’s wealth accumulation, whereas ending a marriage had negative effects. The estimated wealth premium on married men is about 60 percent per marital year. This substantial wealth premium is closely related to wives’ specializing in household production, and farmers and craftsmen economically benefited from the unpaid labor of their wives. PMID:24058226
Electroweak Sudakov logarithms and real gauge-boson radiation in the TeV region

NASA Astrophysics Data System (ADS)

Bell, G.; Kühn, J. H.; Rittinger, J.

2010-12-01

Electroweak radiative corrections give rise to large negative, double-logarithmically enhanced corrections in the TeV region. These are partly compensated by real radiation and, moreover, affected by selecting isospin-non-invariant external states. We investigate the impact of real gauge boson radiation more quantitatively by considering different restricted final state configurations. We consider successively a massive abelian gauge theory, a spontaneously broken SU(2) theory and the electroweak Standard Model. We find that details of the choice of the phase space cuts, in particular whether a fraction of collinear and soft radiation is included, have a strong impact on the relative amount of real and virtual corrections.
HPV Integration in HNSCC Correlates with Survival Outcomes, Immune Response Signatures, and Candidate Drivers.

PubMed

Koneva, Lada A; Zhang, Yanxiao; Virani, Shama; Hall, Pelle B; McHugh, Jonathan B; Chepeha, Douglas B; Wolf, Gregory T; Carey, Thomas E; Rozek, Laura S; Sartor, Maureen A

2018-01-01

The incidence of human papillomavirus (HPV)-related oropharynx cancer has steadily increased over the past two decades and now represents a majority of oropharyngeal cancer cases. Integration of the HPV genome into the host genome is a common event during carcinogenesis that has clinically relevant effects if the viral early genes are transcribed. Understanding the impact of HPV integration on clinical outcomes of head and neck squamous cell carcinoma (HNSCC) is critical for implementing deescalated treatment approaches for HPV + HNSCC patients. RNA sequencing (RNA-seq) data from HNSCC tumors ( n = 84) were used to identify and characterize expressed integration events, which were overrepresented near known head and neck, lung, and urogenital cancer genes. Five genes were recurrent, including CD274 (PD-L1) A significant number of genes detected to have integration events were found to interact with Tp63, ETS, and/or FOX1A. Patients with no detected integration had better survival than integration-positive and HPV - patients. Furthermore, integration-negative tumors were characterized by strongly heightened signatures for immune cells, including CD4 + , CD3 + , regulatory, CD8 + T cells, NK cells, and B cells, compared with integration-positive tumors. Finally, genes with elevated expression in integration-negative specimens were strongly enriched with immune-related gene ontology terms, while upregulated genes in integration-positive tumors were enriched for keratinization, RNA metabolism, and translation. Implications: These findings demonstrate the clinical relevancy of expressed HPV integration, which is characterized by a change in immune response and/or aberrant expression of the integration-harboring cancer-related genes, and suggest strong natural selection for tumor cells with expressed integration events in key carcinogenic genes. Mol Cancer Res; 16(1); 90-102. ©2017 AACR . ©2017 American Association for Cancer Research.
Evaluation of two main RNA-seq approaches for gene quantification in clinical RNA sequencing: polyA+ selection versus rRNA depletion.

PubMed

Zhao, Shanrong; Zhang, Ying; Gamini, Ramya; Zhang, Baohong; von Schack, David

2018-03-19

To allow efficient transcript/gene detection, highly abundant ribosomal RNAs (rRNA) are generally removed from total RNA either by positive polyA+ selection or by rRNA depletion (negative selection) before sequencing. Comparisons between the two methods have been carried out by various groups, but the assessments have relied largely on non-clinical samples. In this study, we evaluated these two RNA sequencing approaches using human blood and colon tissue samples. Our analyses showed that rRNA depletion captured more unique transcriptome features, whereas polyA+ selection outperformed rRNA depletion with higher exonic coverage and better accuracy of gene quantification. For blood- and colon-derived RNAs, we found that 220% and 50% more reads, respectively, would have to be sequenced to achieve the same level of exonic coverage in the rRNA depletion method compared with the polyA+ selection method. Therefore, in most cases we strongly recommend polyA+ selection over rRNA depletion for gene quantification in clinical RNA sequencing. Our evaluation revealed that a small number of lncRNAs and small RNAs made up a large fraction of the reads in the rRNA depletion RNA sequencing data. Thus, we recommend that these RNAs are specifically depleted to improve the sequencing depth of the remaining RNAs.
Resolving the conundrum of inbreeding depression but no inbreeding avoidance: Estimating sex‐specific selection on inbreeding by song sparrows (Melospiza melodia)

PubMed Central

Reid, Jane M.; Arcese, Peter; Bocedi, Greta; Duthie, A. Bradley; Wolak, Matthew E.; Keller, Lukas F.

2015-01-01

Inbreeding avoidance among interacting females and males is not always observed despite inbreeding depression in offspring fitness, creating an apparent “inbreeding paradox.” This paradox could be resolved if selection against inbreeding was in fact weak, despite inbreeding depression. However, the net magnitude and direction of selection on the degree to which females and males inbreed by pairing with relatives has not been explicitly estimated. We used long‐term pedigree data to estimate phenotypic selection gradients on the degree of inbreeding that female and male song sparrows (Melospiza melodia) expressed by forming socially persistent breeding pairs with relatives. Fitness was measured as the total numbers of offspring and grand offspring contributed to the population, and as corresponding expected numbers of identical‐by‐descent allele copies, thereby accounting for variation in offspring survival, reproduction, and relatedness associated with variation in parental inbreeding. Estimated selection gradients on the degree to which individuals paired with relatives were weakly positive in females, but negative in males that formed at least one socially persistent pairing. However, males that paired had higher mean fitness than males that remained socially unpaired. These analyses suggest that net selection against inbreeding may be weak in both sexes despite strong inbreeding depression, thereby resolving the “inbreeding paradox.” PMID:26420476
Portrayal of negative qualities in a doctor as a potential teaching tool in medical ethics and humanism: Journey to the End of Night by Louis-Ferdinand Celine.

PubMed

Wolf, G

2006-02-01

Fictional stories about physicians and patients are increasingly used as a powerful teaching resource for medical students. Very often, but not exclusively, stories of physicians as positive role models are selected to teach students virtues and ethical values. Negative role models are rarely used and if so, physicians are rather described as medical quacks in such fiction then exhibiting primarily a corrupted character. I suggest that a fictional story that presents exclusively a negative role model of a physician could also be a valuable, admittedly difficult, teaching resource to demonstrate the consequences of absolute loss of ethical standards and virtues in physicians. A not widely known example of this genre is Louis-Ferdinand Céline's (1894-1961) novel Voyage au bout de la nuit (Journey to the End of the Night), published in 1932. Having a strong autobiographical background, the novel described the adventures of the medicine student, Ferdinand Bardamu, during the first world war, in the African colonies as a trader, in the United States of America as factory worker, and later after finishing his education, as a doctor for the poor. Unfortunately, Dr Bardamu develops an unprofessional, even criminal behaviour, and may serve as a negative role model for the virtues of physicians. This article will familiarise the reader with the novel and its physician author.
Cognitive reappraisal and secondary control coping: associations with working memory, positive and negative affect, and symptoms of anxiety/depression.

PubMed

Andreotti, Charissa; Thigpen, Jennifer E; Dunn, Madeleine J; Watson, Kelly; Potts, Jennifer; Reising, Michelle M; Robinson, Kristen E; Rodriguez, Erin M; Roubinov, Danielle; Luecken, Linda; Compas, Bruce E

2013-01-01

The current study examined the relations of measures of cognitive reappraisal and secondary control coping with working memory abilities, positive and negative affect, and symptoms of anxiety and depression in young adults (N=124). Results indicate significant relations between working memory abilities and reports of secondary control coping and between reports of secondary control coping and cognitive reappraisal. Associations were also found between measures of secondary control coping and cognitive reappraisal and positive and negative affect and symptoms of depression and anxiety. Further, the findings suggest that reports of cognitive reappraisal may be more strongly predictive of positive affect whereas secondary control coping may be more strongly predictive of negative affect and symptoms of depression and anxiety. Overall, the results suggest that current measures of secondary control coping and cognitive reappraisal capture related but distinct constructs and suggest that the assessment of working memory may be more strongly related to secondary control coping in predicting individual differences in distress.
Electron transfer driven decomposition of adenine and selected analogs as probed by experimental and theoretical methods

NASA Astrophysics Data System (ADS)

Cunha, T.; Mendes, M.; Ferreira da Silva, F.; Eden, S.; García, G.; Bacchus-Montabonel, M.-C.; Limão-Vieira, P.

2018-04-01

We report on a combined experimental and theoretical study of electron-transfer-induced decomposition of adenine (Ad) and a selection of analog molecules in collisions with potassium (K) atoms. Time-of-flight negative ion mass spectra have been obtained in a wide collision energy range (6-68 eV in the centre-of-mass frame), providing a comprehensive investigation of the fragmentation patterns of purine (Pu), adenine (Ad), 9-methyl adenine (9-mAd), 6-dimethyl adenine (6-dimAd), and 2-D adenine (2-DAd). Following our recent communication about selective hydrogen loss from the transient negative ions (TNIs) produced in these collisions [T. Cunha et al., J. Chem. Phys. 148, 021101 (2018)], this work focuses on the production of smaller fragment anions. In the low-energy part of the present range, several dissociation channels that are accessible in free electron attachment experiments are absent from the present mass spectra, notably NH2 loss from adenine and 9-methyl adenine. This can be understood in terms of a relatively long transit time of the K+ cation in the vicinity of the TNI tending to enhance the likelihood of intramolecular electron transfer. In this case, the excess energy can be redistributed through the available degrees of freedom inhibiting fragmentation pathways. Ab initio theoretical calculations were performed for 9-methyl adenine (9-mAd) and adenine (Ad) in the presence of a potassium atom and provided a strong basis for the assignment of the lowest unoccupied molecular orbitals accessed in the collision process.
Designing effective anticancer-radiopeptides. A Molecular Dynamics study of their interaction with model tumor and healthy cell membranes.

PubMed

Capozzi, E; Aureli, S; Minicozzi, V; Rossi, G C; Stellato, F; Morante, S

2018-06-06

One of the greatest merit of the use of radiopeptides in oncology is their selectivity which, however, brings about the drawback that each radiopeptide is specific for a given tumor type. To overcome this problem the direction currently taken in drug design is that of radiolabelling peptide hormones (or their analogues), relying on their intrinsic ability to bind to specific receptors in precise areas of the human body, at the cost, however, of a poor selectivity against healthy cells. We present here an extensive Molecular Dynamics study of a promising alternative inspired by the mechanism through which antimicrobial peptides interact with the negatively charged bacterial membranes. Appropriately modifying the human antimicrobial peptide, LL-37, we designed a functionalized radionuclide carrier capable of binding more strongly to the negatively charged (model) tumor membranes than to the neutral healthy ones. The mechanism behind this behaviour relies on the fact that at the slight acidic pH surrounding tumor tissues the histidines belonging to the peptide get protonated thus making it positively charged. We have investigated by an extended numerical study the way in which this artificial peptide interacts with models of tumor and healthy cell membranes, proving by Potential Mean Force calculations that the affinity of the peptide to model tumor membranes is significantly larger than to healthy ones. These features (high affinity and generic tumor selectivity) recommend antimicrobial derived customized carriers as promising theranostic constructs in cancer diagnostic and therapy. Copyright © 2018 Elsevier B.V. All rights reserved.
Production of intense negative hydrogen beams with polarized nuclei by selective neutralization of cold negative ions

DOEpatents

Hershcovitch, A.

1984-02-13

A process for selectively neutralizing H/sup -/ ions in a magnetic field to produce an intense negative hydrogen ion beam with spin polarized protons. Characteristic features of the process include providing a multi-ampere beam of H/sup -/ ions that are
A possible cause of the AO polarity reversal from winter to summer in 2010 and its relation to hemispheric extreme summer weather

NASA Astrophysics Data System (ADS)

Otomi, Y.; Tachibana, Y.; Nakamura, T.

2012-12-01

In 2010, the Northern Hemisphere, in particular Russia, Europe and Japan, experienced an abnormally hot summer characterized by record-breaking warm temperatures and associated with a strongly positive Arctic Oscillation (AO). In contrast, in winter 2009/2010, the continent suffered from anomalously cold weather associated with a record-breaking negative AO. The winter-to-summer of the AO index during 2009/2010 evolved as follows: a strongly negative wintertime AO index continued until May, after which it abruptly changed, becoming strongly positive in July and continuing so until the beginning of August. The abrupt change of the AO index from strongly negative to strongly positive in 2010 thus corresponded to the change from the abnormally cold winter of 2009/2010 to the abnormally hot summer of 2010, which shows that the AO index is a good indicator of abnormal weather on a planetary-scale, and that extra-seasonal prediction of the AO is a key to long-term forecasting. In this study, we therefore aimed to examine the cause of the 2010 change in the AO index from strongly negative to strongly positive. We suggest that an oceanic memory of the strongly negative wintertime AO may have influenced the strongly positive summertime AO. The winter sea surface temperatures (SST) in the North Atlantic Ocean showed a tripolar anomaly pattern which is warm SST anomalies over the tropics and high latitudes and cold SST anomalies over the midlatitudes. The strongly negative wintertime AO would cause the warm SST anomaly in this region. The warm SST anomalies continued into summer 2010 because of the large oceanic heat capacity. In May and June, the heat flux anomaly changed from downward to upward in the tropics, and in July and August, the center of the upward anomaly moved westward. The area of the upward heat flux anomaly coincided with the area of the warm SST anomaly from May to August. The numerical model experiment showed that the tripolar SST pattern resulted in an anomalous height and wind pattern that caused a blocking high over Europe. The observed wave activity flux also seems to emanate from Europe. This midlatitude atmospheric response implies that strengthening of the positive geopotential anomalies over Europe was associated with the Atlantic tripolar SST anomaly. The positive geopotential anomaly in the area of the polar jet stream caused eastward propagation of Rossby waves, and the exceeding amplification of Rossby waves might have led to the formation of blocking anticyclones. As a consequence of these interactions, the positive AO pressure pattern can continue for a long time. Thus, a possible cause of the AO polarity reversal might be the "memory" of the negative winter AO in the North Atlantic Ocean, suggesting an interseasonal linkage of the AO in which the oceanic memory of a wintertime negative AO induces a positive AO in the following summer. Understanding of this interseasonal linkage may aid in the long-term prediction of such abnormal summer events. If this reversal pattern recurs, it might be possible to predict the summertime AO from the wintertime AO. Main parts of this study were published in Climatic Dynamics by Otomi et al, (2012).
Bilayer synergetic coupling double negative acoustic metasurface and cloak.

PubMed

Ma, Fuyin; Huang, Meng; Xu, Yicai; Wu, Jiu Hui

2018-04-12

In this paper, we propose a bilayer plate-type lightweight double negative metasurface based on a new synergetic coupling design concept, by which the perfect absorption, double negative bands, free manipulation of phase shifts with a 2π span and acoustic cloak can be successively realized. Firstly, the synergetic behavior between resonant and anti-resonant plates is presented to construct a bilayer unit in which each component respectively provides a pre-defined function in realizing the perfect absorption. Based on this bilayer structure, a double negative band with simultaneously negative effective mass density and bulk modulus is obtained, which, as a metasurface, can obtain continuous phase shifts almost completely covering a 2π range, thus facilitating the design of a three-dimensional (3D) acoustic cloak. In addition, based on this strong sound absorption concept, a two-dimensional (2D) omnidirectional broadband acoustical dark skin, covering between 800 to 6000 Hz, is also demonstrated through the proposed bilayer plate-type structure form. The proposed design concepts and metasurfaces have widespread potential application values in strong sound attenuation, filtering, superlens, imaging, cloak, and extraordinary wave steering, in which the attributes of strong absorption, double negative parameters or continuous phase shifts with full 2π span are required to realize the expected extraordinary physical features.
Who benefits most from college? Evidence for negative selection in heterogeneous economic returns to higher education *

PubMed Central

Brand, Jennie E.; Xie, Yu

2009-01-01

We consider how the economic return to a college education varies across members of the U.S. population. Based on principles of comparative advantage, positive selection is commonly presumed, i.e., individuals who are most likely to select into college benefit most from college. Net of observed economic and non-economic factors influencing college attendance, we conjecture that individuals who are least likely to obtain a college education benefit most from college. We call this theory the negative selection hypothesis. To adjudicate between the two hypotheses, we study the effects of completing college on earnings by propensity score strata using an innovative hierarchical linear model with data from the National Longitudinal Survey of Youth 1979 and the Wisconsin Longitudinal Study. For both data sources, for men and for women, and for every observed stage of the life course, we find evidence suggesting negative selection. Results from auxiliary analyses lend further support to the negative selection interpretation of the results. PMID:20454549
Situation Selection and Modification for Emotion Regulation in Younger and Older Adults

PubMed Central

Livingstone, Kimberly M.; Isaacowitz, Derek M.

2016-01-01

This research investigated age differences in use and effectiveness of situation selection and situation modification for emotion regulation. Socioemotional selectivity theory suggests stronger emotional well-being goals in older age; emotion regulation may support this goal. Younger and older adults assigned to an emotion regulation or “just view” condition first freely chose to engage with negative, neutral, or positive material (situation selection), then chose to view or skip negative and positive material (situation modification), rating affect after each experience. In both tasks, older adults in both goal conditions demonstrated pro-hedonic emotion regulation, spending less time with negative material compared to younger adults. Younger adults in the regulate condition also engaged in pro-hedonic situation selection, but not modification. Whereas situation selection was related to affect, modification of negative material was not. This research supports more frequent pro-hedonic motivation in older age, as well as age differences in use of early-stage emotion regulation. PMID:26998196

Just How Bad Negative Affect is for Your Health Depends on Culture

PubMed Central

Curhan, Katherine B.; Sims, Tamara; Markus, Hazel Rose; Kitayama, Shinobu; Karasawa, Mayumi; Kawakami, Norito; Love, Gayle D.; Coe, Christopher L.; Miyamoto, Yuri; Ryff, Carol D.

2014-01-01

Pressman, Lopez and Gallagher (2013) conclude that across the globe negative emotions are bad for one’s health. Yet, just how bad negative emotions are for health depends on culture. In U.S. American contexts, negative feelings are construed as the individual’s responsibility and as harmful. In Japanese contexts, negative feelings are construed as rooted in relationships and as natural. Using six clinically-relevant measures and two representative samples, we tested the hypothesis that negative affect is more strongly associated with poor health in the U.S. (n = 1,741) than in Japan (n = 988). Negative affect more strongly predicted poor health in the U.S. than in Japan for multi-item assessments of physical health (chronic conditions, physical functioning) and mental health (psychological well-being, self-esteem). There were no differences for single-item health assessments (life satisfaction, global health). These findings underscore the need for further theoretically-driven investigations of how cultural construals shape the emotion-health link. PMID:25304884
Non-negative matrix factorization in texture feature for classification of dementia with MRI data

NASA Astrophysics Data System (ADS)

Sarwinda, D.; Bustamam, A.; Ardaneswari, G.

2017-07-01

This paper investigates applications of non-negative matrix factorization as feature selection method to select the features from gray level co-occurrence matrix. The proposed approach is used to classify dementia using MRI data. In this study, texture analysis using gray level co-occurrence matrix is done to feature extraction. In the feature extraction process of MRI data, we found seven features from gray level co-occurrence matrix. Non-negative matrix factorization selected three features that influence of all features produced by feature extractions. A Naïve Bayes classifier is adapted to classify dementia, i.e. Alzheimer's disease, Mild Cognitive Impairment (MCI) and normal control. The experimental results show that non-negative factorization as feature selection method able to achieve an accuracy of 96.4% for classification of Alzheimer's and normal control. The proposed method also compared with other features selection methods i.e. Principal Component Analysis (PCA).
Thymic selection threshold defined by compartmentalization of Ras/MAPK signalling.

PubMed

Daniels, Mark A; Teixeiro, Emma; Gill, Jason; Hausmann, Barbara; Roubaty, Dominique; Holmberg, Kaisa; Werlen, Guy; Holländer, Georg A; Gascoigne, Nicholas R J; Palmer, Ed

2006-12-07

A healthy individual can mount an immune response to exogenous pathogens while avoiding an autoimmune attack on normal tissues. The ability to distinguish between self and non-self is called 'immunological tolerance' and, for T lymphocytes, involves the generation of a diverse pool of functional T cells through positive selection and the removal of overtly self-reactive thymocytes by negative selection during T-cell ontogeny. To elucidate how thymocytes arrive at these cell fate decisions, here we have identified ligands that define an extremely narrow gap spanning the threshold that distinguishes positive from negative selection. We show that, at the selection threshold, a small increase in ligand affinity for the T-cell antigen receptor leads to a marked change in the activation and subcellular localization of Ras and mitogen-activated protein kinase (MAPK) signalling intermediates and the induction of negative selection. The ability to compartmentalize signalling molecules differentially in the cell endows the thymocyte with the ability to convert a small change in analogue input (affinity) into a digital output (positive versus negative selection) and provides the basis for establishing central tolerance.
Use of negative pressure wound therapy in the treatment of neonatal and pediatric wounds: a retrospective examination of clinical outcomes.

PubMed

Baharestani, Mona Mylene

2007-06-01

The clinical effectiveness of negative pressure wound therapy for the management of acute and chronic wounds is well documented in the adult population but information regarding its use in the pediatric population is limited. A retrospective, descriptive study was conducted to examine the clinical outcomes of using negative pressure wound therapy in the treatment of pediatric wounds. The medical records of 24 consecutive pediatric patients receiving negative pressure wound therapy were reviewed. Demographic data, wound etiology, time to closure, closure method, duration of negative pressure wound therapy, complications, dressing change frequency, dressing type used, and pressure settings were analyzed. All categorical variables in the dataset were summarized using frequency (count and percentages) and all continuous variables were summarized using median (minimum, maximum). The 24 pediatric patients (mean age 8.5 years [range 14 days to 18 years old]) had 24 wounds - 12 (50%) were infected at baseline. Sixteen patients had hypoalbuminemia and six had exposed hardware and bone in their wounds. Twenty-two wounds reached full closure in a median time of 10 days (range 2 to 45) following negative pressure wound therapy and flap closure (11), split-thickness skin graft (three), secondary (four), and primary (four) closure. Pressures used in this population ranged from 50 to 125 mm Hg and most wounds were covered with reticulated polyurethane foam. One patient developed a fistula during the course of negative pressure wound therapy. When coupled with appropriate systemic antibiotics, surgical debridement, and medical and nutritional optimization, in this population negative pressure wound therapy resulted in rapid granulation tissue and 92% successful wound closure. Future neonatal and pediatric negative pressure wound therapy usage registries and prospective studies are needed to provide a strong evidence base from which treatment decisions can be made in the management of these challenging cases, especially pertaining to the safety and efficacy of pressure settings, dressings, and interposing contact layer selection.
Genetic structure of colline and montane populations of an endangered plant species

PubMed Central

Maurice, Tiphaine; Matthies, Diethart; Muller, Serge; Colling, Guy

2016-01-01

Due to land-use intensification, lowland and colline populations of many plants of nutrient-poor grasslands have been strongly fragmented in the last decades, with potentially negative consequences for their genetic diversity and persistence. Populations in mountains might represent a genetic reservoir for grassland plants, because they have been less affected by land-use changes. We studied the genetic structure and diversity of colline and montane Vosges populations of the threatened perennial plant Arnica montana in western central Europe using AFLP markers. Our results indicate that in contrast to our expectation even strongly fragmented colline populations of A. montana have conserved a considerable amount of genetic diversity. However, mean seed mass increased with the proportion of polymorphic loci, suggesting inbreeding effects in low diversity populations. At a similar small geographical scale, there was a clear IBD pattern for the montane Vosges but not for the colline populations. However, there was a strong IBD-pattern for the colline populations at a large geographical scale suggesting that this pattern is a legacy of historical gene flow, as most of the colline populations are today strongly isolated from each other. Genetic differentiation between colline and montane Vosges populations was strong. Moreover, results of a genome scan study indicated differences in loci under selection, suggesting that plants from montane Vosges populations might be maladapted to conditions at colline sites. Our results suggest caution in using material from montane populations of rare plants for the reinforcement of small genetically depauperate lowland populations. PMID:27519913
Spatial and temporal patterns of neutral and adaptive genetic variation in the endangered African wild dog (Lycaon pictus).

PubMed

Marsden, Clare D; Woodroffe, Rosie; Mills, Michael G L; McNutt, J Weldon; Creel, Scott; Groom, Rosemary; Emmanuel, Masenga; Cleaveland, Sarah; Kat, Pieter; Rasmussen, Gregory S A; Ginsberg, Joshua; Lines, Robin; André, Jean-Marc; Begg, Colleen; Wayne, Robert K; Mable, Barbara K

2012-03-01

Deciphering patterns of genetic variation within a species is essential for understanding population structure, local adaptation and differences in diversity between populations. Whilst neutrally evolving genetic markers can be used to elucidate demographic processes and genetic structure, they are not subject to selection and therefore are not informative about patterns of adaptive variation. As such, assessments of pertinent adaptive loci, such as the immunity genes of the major histocompatibility complex (MHC), are increasingly being incorporated into genetic studies. In this study, we combined neutral (microsatellite, mtDNA) and adaptive (MHC class II DLA-DRB1 locus) markers to elucidate the factors influencing patterns of genetic variation in the African wild dog (Lycaon pictus); an endangered canid that has suffered extensive declines in distribution and abundance. Our genetic analyses found all extant wild dog populations to be relatively small (N(e) < 30). Furthermore, through coalescent modelling, we detected a genetic signature of a recent and substantial demographic decline, which correlates with human expansion, but contrasts with findings in some other African mammals. We found strong structuring of wild dog populations, indicating the negative influence of extensive habitat fragmentation and loss of gene flow between habitat patches. Across populations, we found that the spatial and temporal structure of microsatellite diversity and MHC diversity were correlated and strongly influenced by demographic stability and population size, indicating the effects of genetic drift in these small populations. Despite this correlation, we detected signatures of selection at the MHC, implying that selection has not been completely overwhelmed by genetic drift. © 2012 Blackwell Publishing Ltd.
The relationship between internalized stigma, negative symptoms and social functioning in schizophrenia: the mediating role of self-efficacy.

PubMed

Hill, Kimberley; Startup, Mike

2013-04-30

The broad aim of the present study was to gain a greater understanding of the processes that contribute to negative symptoms and social functioning in schizophrenia. More specifically, a theoretical model was proposed predicting that self-efficacy would mediate the relationship between internalized stigma and both negative symptoms and social functioning in schizophrenia. Initial analyses revealed that all variables were correlated. Specifically, internalized stigma was strongly correlated with negative symptoms, social functioning and self-efficacy. Furthermore, self-efficacy was strongly related to negative symptoms and moderately associated with social functioning. Further analyses however did not support the mediational role of self-efficacy. The theoretical and clinical implications of the findings, together with recommendations for future research, are outlined. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
Dominant positive and negative selection using a hygromycin phosphotransferase-thymidine kinase fusion gene.

PubMed

Lupton, S D; Brunton, L L; Kalberg, V A; Overell, R W

1991-06-01

The hygromycin phosphotransferase gene was fused in-frame with the herpes simplex virus type 1 thymidine kinase gene. The resulting fusion gene (termed HyTK) confers hygromycin B resistance for dominant positive selection and ganciclovir sensitivity for negative selection and provides a means by which these selectable phenotypes may be expressed and regulated as a single genetic entity.
Medical barriers to emergency contraception: a cross-sectional survey of doctors in North India.

PubMed

Khan, M E; Dixit, Anvita; Bhatnagar, Isha; Brady, Martha

2014-05-01

Some medical doctors in India have publicly expressed opposition to making emergency contraceptive pills (ECPs) easily accessible, even though ECPs are included in the method mix of the Ministry of Health and Family Welfare program and as an over-the-counter (OTC) product. Such opposition affects access to ECPs by influencing policy, procurement, and distribution, besides stigmatizing the ECP user. This study was conducted to assess ECP knowledge, attitudes, and practices of doctors in North India. A cross-sectional survey of 83 doctors who provide ECPs, randomly selected from 3 cities in the state of Uttar Pradesh, was conducted in 2011. The quantitative data were complemented by 19 in-depth interviews with purposively selected senior gynecologists and other opinion leaders. All surveyed physicians cited the correct dose and regimen for ECPs. However, the large majority of those surveyed believed that ECPs work by preventing implantation. (The best evidence currently indicates that ECPs do not work by preventing implantation.) Most doctors also believed incorrectly that ECPs have several contraindications and side effects. They also had strong reservations against OTC provision of ECPs by pharmacists and community health workers (CHWs) and negative attitudes toward ECP users, which serve as serious medical barriers to mainstreaming use of ECPs. Physicians and their professional associations exert a strong influence on the operationalization of national contraceptive policies. Evidence-based advocacy and educational campaigns targeting doctors are needed to address and resolve their reservations about ECPs, particularly about its provision as an OTC product and its distribution by CHWs. Partnerships with medical associations can help reduce doctors' negative attitudes and create a conducive environment for influencing clinical practices. Such changes are needed to increase the availability and use of ECPs as part of a package of a full range of contraceptive method options to prevent unwanted pregnancy among the most vulnerable populations.
Is the European spatial distribution of the HIV-1-resistant CCR5-Delta32 allele formed by a breakdown of the pathocenosis due to the historical Roman expansion?

PubMed

Faure, Eric; Royer-Carenzi, Manuela

2008-12-01

We studied the possible effects of the expansion of ancient Mediterranean civilizations during the five centuries before and after Christ on the European distribution of the mutant allele for the chemokine receptor gene CCR5 which has a 32-bp deletion (CCR5-Delta32). There is a strong evidence for the unitary origin of the CCR5-Delta32 mutation, this it is found principally in Europe and Western Asia, with generally a north-south downhill cline frequency. Homozygous carriers of this mutation show a resistance to HIV-1 infection and a slower progression towards AIDS. However, HIV has clearly emerged too recently to have been the selective force on CCR5. Our analyses showed strong negative correlations in Europe between the allele frequency and two historical parameters, i.e. the first colonization dates by the great ancient Mediterranean civilizations, and the distances from the Northern frontiers of the Roman Empire in its greatest expansion. Moreover, other studies have shown that the deletion frequencies in both German Bronze Age and Swedish Neolithic populations were similar to those found in the corresponding modern populations, and this deletion has been found in ancient DNA of around 7000 years ago, suggesting that in the past, the deletion frequency could have been relatively high in European populations. In addition, in West Nile virus pathogenesis, CCR5 plays an antimicrobial role showing that host genetic factors are highly pathogen-specific. Our results added to all these previous data suggest that the actual European allele frequency distribution might not be due to genes spreading, but to a negative selection resulting in the spread of pathogens principally during Roman expansion. Indeed, as gene flows from colonizers to European native populations were extremely low, the mutational changes might be associated with vulnerability to imported infections. To date, the nature of the parasites remains unknown; however, zoonoses could be incriminated.
Chicken meat quality: genetic variability and relationship with growth and muscle characteristics

PubMed Central

Le Bihan-Duval, Elisabeth; Debut, Martine; Berri, Cécile M; Sellier, Nadine; Santé-Lhoutellier, Véronique; Jégo, Yves; Beaumont, Catherine

2008-01-01

Background The qualitative properties of the meat are of major importance for poultry breeding, since meat is now widely consumed as cuts or as processed products. The aim of this study was to evaluate the genetic parameters of several breast meat quality traits and their genetic relationships with muscle characteristics in a heavy commercial line of broilers. Results Significant levels of heritability (averaging 0.3) were obtained for breast meat quality traits such as pH at 15 min post-slaughter, ultimate pH (pHu), color assessed by lightness L*, redness a* and yellowness b*, drip loss, thawing-cooking loss and shear-force. The rate of decrease in pH early post-mortem and the final pH of the meat were shown to be key factors of chicken meat quality. In particular, a decrease in the final pH led to paler, more exudative and tougher breast meat. The level of glycogen stored in breast muscle estimated by the Glycolytic Potential (GP) at slaughter time was shown to be highly heritable (h2 0.43). There was a very strong negative genetic correlation (rg) with ultimate meat pH (rg -0.97), suggesting a common genetic control for GP and pHu. While breast muscle weight was genetically positively correlated with fiber size (rg 0.76), it was negatively correlated with the level of glycogen stored in the muscle (rg -0.58), and as a consequence it was positively correlated with the final pH of the meat (rg 0.84). Conclusion This genetic study confirmed that selection should be useful to improve meat characteristics of meat-type chickens without impairing profitability because no genetic conflict was detected between meat quality and meat quantity. Moreover, the results suggested relevant selection criteria such as ultimate pH, which is strongly related to color, water-holding capacity and texture of the meat in this heavy chicken line. PMID:18706119
Placenta-specific1 (PLAC1) is a potential target for antibody-drug conjugate-based prostate cancer immunotherapy.

PubMed

Nejadmoghaddam, Mohammad-Reza; Zarnani, Amir-Hassan; Ghahremanzadeh, Ramin; Ghods, Roya; Mahmoudian, Jafar; Yousefi, Maryam; Nazari, Mahboobeh; Ghahremani, Mohammad Hossein; Abolhasani, Maryam; Anissian, Ali; Mahmoudi, Morteza; Dinarvand, Rassoul

2017-10-17

Our recent findings strongly support the idea of PLAC1 being as a potential immunotherapeutic target in prostate cancer (PCa). Here, we have generated and evaluated an anti-placenta-specific1 (PLAC1)-based antibody drug conjugate (ADC) for targeted immunotherapy of PCa. Prostate cancer cells express considerable levels of PLAC1. The Anti-PLAC1 clone, 2H12C12, showed high reactivity with recombinant PLAC1 and selectivity recognized PLAC1 in prostate cancer cells but not in LS180 cells, the negative control. PLAC1 binding induced rapid internalization of the antibody within a few minutes which reached to about 50% after 15 min and almost completed within an hour. After SN38 conjugation to antibody, a drug-antibody ratio (DAR) of about 5.5 was achieved without apparent negative effect on antibody affinity to cell surface antigen. The ADC retained intrinsic antibody activity and showed enhanced and selective cytotoxicity with an IC50 of 62 nM which was about 15-fold lower compared to free drug. Anti-PLAC1-ADC induced apoptosis in human primary prostate cancer cells and prostate cell lines. No apparent cytotoxic effect was observed in in vivo animal safety experiments. Our newly developed anti-PLAC1-based ADCs might pave the way for a reliable, efficient, and novel immunotherapeutic modality for patients with PCa.
Do multiple herbivores maintain chemical diversity of Scots pine monoterpenes?

PubMed Central

Iason, Glenn R.; O'Reilly-Wapstra, Julianne M.; Brewer, Mark J.; Summers, Ron W.; Moore, Ben D.

2011-01-01

A central issue in our understanding of the evolution of the diversity of plant secondary metabolites (PSMs) is whether or not compounds are functional, conferring an advantage to the plant, or non-functional. We examine the hypothesis that the diversity of monoterpene PSMs within a plant species (Scots pine Pinus sylvestris) may be explained by different compounds acting as defences against high-impact herbivores operating at different life stages. We also hypothesize that pairwise coevolution, with uncorrelated interactions, is more likely to result in greater PSM diversity, than diffuse coevolution. We tested whether up to 13 different monoterpenes in Scots pine were inhibitory to herbivory by slugs (Arion ater), bank voles (Clethrionomys glareolus), red deer (Cervus elaphus) and capercaillie (Tetrao urogallus), each of which attack trees at a different life stage. Plants containing more α-pinene were avoided by both slugs and capercaillie, which may act as reinforcing selective agents for this dominant defensive compound. Herbivory by red deer and capercaillie were, respectively, weakly negatively associated with δ3-carene, and strongly negatively correlated with the minor compound β-ocimene. Three of the four herbivores are probably contributory selective agents on some of the terpenes, and thus maintain some, but by no means all, of the phytochemical diversity in the species. The correlated defensive function of α-pinene against slugs and capercaillie is consistent with diffuse coevolutionary processes. PMID:21444308
How do scientists perceive the current publication culture? A qualitative focus group interview study among Dutch biomedical researchers.

PubMed

Tijdink, J K; Schipper, K; Bouter, L M; Maclaine Pont, P; de Jonge, J; Smulders, Y M

2016-02-17

To investigate the biomedical scientist's perception of the prevailing publication culture. Qualitative focus group interview study. Four university medical centres in the Netherlands. Three randomly selected groups of biomedical scientists (PhD, postdoctoral staff members and full professors). Main themes for discussion were selected by participants. Frequently perceived detrimental effects of contemporary publication culture were the strong focus on citation measures (like the Journal Impact Factor and the H-index), gift and ghost authorships and the order of authors, the peer review process, competition, the funding system and publication bias. These themes were generally associated with detrimental and undesirable effects on publication practices and on the validity of reported results. Furthermore, senior scientists tended to display a more cynical perception of the publication culture than their junior colleagues. However, even among the PhD students and the postdoctoral fellows, the sentiment was quite negative. Positive perceptions of specific features of contemporary scientific and publication culture were rare. Our findings suggest that the current publication culture leads to negative sentiments, counterproductive stress levels and, most importantly, to questionable research practices among junior and senior biomedical scientists. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
Synoptic meteorological modes of variability for fine particulate matter (PM2.5) air quality in major metropolitan regions of China

NASA Astrophysics Data System (ADS)

Leung, Danny M.; Tai, Amos P. K.; Mickley, Loretta J.; Moch, Jonathan M.; van Donkelaar, Aaron; Shen, Lu; Martin, Randall V.

2018-05-01

In his study, we use a combination of multivariate statistical methods to understand the relationships of PM2.5 with local meteorology and synoptic weather patterns in different regions of China across various timescales. Using June 2014 to May 2017 daily total PM2.5 observations from ˜ 1500 monitors, all deseasonalized and detrended to focus on synoptic-scale variations, we find strong correlations of daily PM2.5 with all selected meteorological variables (e.g., positive correlation with temperature but negative correlation with sea-level pressure throughout China; positive and negative correlation with relative humidity in northern and southern China, respectively). The spatial patterns suggest that the apparent correlations with individual meteorological variables may arise from common association with synoptic systems. Based on a principal component analysis of 1998-2017 meteorological data to diagnose distinct meteorological modes that dominate synoptic weather in four major regions of China, we find strong correlations of PM2.5 with several synoptic modes that explain 10 to 40 % of daily PM2.5 variability. These modes include monsoonal flows and cold frontal passages in northern and central China associated with the Siberian High, onshore flows in eastern China, and frontal rainstorms in southern China. Using the Beijing-Tianjin-Hebei (BTH) region as a case study, we further find strong interannual correlations of regionally averaged satellite-derived annual mean PM2.5 with annual mean relative humidity (RH; positive) and springtime fluctuation frequency of the Siberian High (negative). We apply the resulting PM2.5-to-climate sensitivities to the Intergovernmental Panel on Climate Change (IPCC) Coupled Model Intercomparison Project Phase 5 (CMIP5) climate projections to predict future PM2.5 by the 2050s due to climate change, and find a modest decrease of ˜ 0.5 µg m-3 in annual mean PM2.5 in the BTH region due to more frequent cold frontal ventilation under the RCP8.5 future, representing a small climate benefit, but the RH-induced PM2.5 change is inconclusive due to the large inter-model differences in RH projections.
PEGylated Self-Assembled Nano-Bacitracin A: Probing the Antibacterial Mechanism and Real-Time Tracing of Target Delivery in Vivo.

PubMed

Hong, Wei; Zhao, Yining; Guo, Yuru; Huang, Chengcheng; Qiu, Peng; Zhu, Jia; Chu, Chun; Shi, Hong; Liu, Mingchun

2018-04-04

Although nano-self-assemblies of hydrophobic-modified bacitracin A with poly(d,l-lactic- co-glycolic acid) (PLGA) (nano-BA PLGA ) have demonstrated promising antibacterial activities, the application of nano-BA PLGA was severely compromised by low water solubility. In this study, a series of PEGylated PLGA copolymers were selected to conjugate with the N-terminus of bacitracin A to construct PEGylated self-assembled nano-BAs and to further develop nano-self-assemblies of bacitracin A with strong antibacterial potency and high solubility. Compared with nano-BA PLGA , all PEGylated nano-BAs, except nano-BA 5k , exhibited strong antibacterial efficiency against both Gram-positive and Gram-negative bacteria by inducing loss of cytoplasmic membrane potential, membrane permeabilization, and leakage of calcein from artificial cell membranes. Studies elucidating the underlying mechanism of PEGylated nano-BAs against Gram-negative bacteria indicated that the strong hydrophobic and van der Waals interactions between PLGA and lipopolysaccharide (LPS) could bind, neutralize, and disassociate LPS, facilitating cellular uptake of the nanoparticles, which could destabilize the membrane, resulting in cell death. Moreover, PEGylated nano-BAs (nano-BA 12k ) with a longer PLGA block were expected to occupy a higher local density of BA mass on the surface and result in stronger hydrophobic and van der Waals interactions with LPS, which were responsible for the enhanced antibacterial activity against Gram-positive and emerging antibacterial activity against Gram-negative bacteria, respectively. In vivo imaging verified that PEGylated nano-BAs exhibited higher inflammatory tissue distribution and longer circulation time than nano-BA PLGA . Therefore, although PEGylation did not affect antibacterial activity, it is necessary for target delivery and resistance to clearance of the observed PEGylated nano-BAs. In vivo, nano-BA 12k also showed the highest therapeutic index against infection burden in a mouse thigh infection model among the tested formulations, which showed good correlation with the in vitro results. In conclusion, nano-BA 12k showed high efficacy in the treatment of invasive infections. This new approach of constructing nanoantibiotics by modification of commercially available antibiotics with PEGylated copolymers is safe, cost-effective, and environmentally friendly.
Natural Selection and Genetic Diversity in the Butterfly Heliconius melpomene.

PubMed

Martin, Simon H; Möst, Markus; Palmer, William J; Salazar, Camilo; McMillan, W Owen; Jiggins, Francis M; Jiggins, Chris D

2016-05-01

A combination of selective and neutral evolutionary forces shape patterns of genetic diversity in nature. Among the insects, most previous analyses of the roles of drift and selection in shaping variation across the genome have focused on the genus Drosophila A more complete understanding of these forces will come from analyzing other taxa that differ in population demography and other aspects of biology. We have analyzed diversity and signatures of selection in the neotropical Heliconius butterflies using resequenced genomes from 58 wild-caught individuals of Heliconius melpomene and another 21 resequenced genomes representing 11 related species. By comparing intraspecific diversity and interspecific divergence, we estimate that 31% of amino acid substitutions between Heliconius species are adaptive. Diversity at putatively neutral sites is negatively correlated with the local density of coding sites as well as nonsynonymous substitutions and positively correlated with recombination rate, indicating widespread linked selection. This process also manifests in significantly reduced diversity on longer chromosomes, consistent with lower recombination rates. Although hitchhiking around beneficial nonsynonymous mutations has significantly shaped genetic variation in H. melpomene, evidence for strong selective sweeps is limited overall. We did however identify two regions where distinct haplotypes have swept in different populations, leading to increased population differentiation. On the whole, our study suggests that positive selection is less pervasive in these butterflies as compared to fruit flies, a fact that curiously results in very similar levels of neutral diversity in these very different insects. Copyright © 2016 by the Genetics Society of America.
The GTPase Rac-1 controls cell fate in the thymus by diverting thymocytes from positive to negative selection.

PubMed

Gomez, M; Kioussis, D; Cantrell, D A

2001-11-01

The positive selection of CD4 or CD8 single-positive mature peripheral T lymphocytes and the deletion of self-reactive cells are crucial for central tolerance in the peripheral immune system. Previously, the guanine nucleotide binding protein Rac-1 has been shown to control pre-T cell development. The present report now describes the actions of Rac-1 in thymocyte selection. The study reveals that this molecule has the striking and unique ability to efficiently divert cells from positive selection into a pathway of negative selection and deletion. The ability of Rac-1 to switch thymocytes from a destiny of positive to negative selection identifies this molecule as a critical regulator of the developmental processes in T cells that are essential for immune homeostasis.
A simple model for solvation in mixed solvents. Applications to the stabilization and destabilization of macromolecular structures.

PubMed

Schellman, J A

1990-08-31

The properties of a simple model for solvation in mixed solvents are explored in this paper. The model is based on the supposition that solvent replacement is a simple one-for-one substitution reaction at macromolecular sites which are independent of one another. This leads to a new form for the binding polynomial in which all terms are associated with ligand interchange rather than ligand addition. The principal solvent acts as one of the ligands. Thermodynamic analysis then shows that thermodynamic binding (i.e., selective interaction) depends on the properties of K'-1, whereas stoichiometric binding (site occupation) depends on K'. K' is a 'practical' interchange equilibrium constant given by (f3/f1)K, where K is the true equilibrium constant for the interchange of components 3 and 1 on the site and f3 and f4 denote their respective activity coefficients on the mole fraction scale. Values of K' less than unity lead to negative selective interaction. It is selective interaction and not occupation number which determines the thermodynamic effects of solvation. When K' greater than 100 on the mole fraction scale or K' greater than 2 on the molality scale (in water), the differences between stoichiometric binding and selective interaction become less than 1%. The theory of this paper is therefore necessary only for very weak binding constants. When K'-1 is small, large concentrations of the added solvent component are required to produce a thermodynamic effect. Under these circumstances the isotherms for the selective interaction and for the excess (or transfer) free energy are strongly dependent on the behavior of the activity coefficients of both solvent components. Two classes of behavior are described depending on whether the components display positive or negative deviations from Raoult's law. Examples which are discussed are aqueous solutions of urea and guanidinium chloride for positive deviations and of sucrose and glucose for negative deviations. Examination of the few studies which have been reported in the literature shows that most of the qualitative features of the stabilization of proteins by sugars and their destabilization by urea and guanidinium chloride are faithfully represented with the model. This includes maxima in the free energy of stabilization and destabilization, decreased and zero selective interaction at high concentrations, etc. These phenomena had no prior explanation. Deficiencies in the model as a representation of solvation in aqueous solution are discussed in the appendix.
Sexual selection on morphological and physiological traits and fluctuating asymmetry in the black scavenger fly Sepsis cynipsea.

PubMed

Blanckenhorn, W U; Kraushaar, U R S; Teuschl, Y; Reim, C

2004-05-01

Previous univariate studies of the fly Sepsis cynipsea (Diptera: Sepsidae) have demonstrated spatiotemporally variable and consequently overall weak sexual selection favouring large male size, which is nevertheless stronger on average than fecundity selection favouring larger females. To identify specific target(s) of selection on body size and additional traits possibly affecting mating success, two multivariate field studies of sexual selection were conducted. In one study using seasonal replicates from three populations, we assessed 15 morphological traits. No clear targets of sexual selection on male size could be detected, perhaps because spatiotemporal variation in selection was again strong. In particular, there was no (current) selection on male abdomen length or fore coxa length, the only traits for which S. cynipsea males are not smaller than females. Interestingly, copulating males had a consistently shorter fore femur base, a secondary sexual trait, and a wider clasper (hypopygium) gap, an external genital trait. In a second study using daily and seasonal replicates from one population, we included physiological measures of energy reserves (lipids, glucose, glycogen), in addition to hind tibia length and fluctuating asymmetry (FA) of all pairs of legs. This study again confirmed the mating advantage of large males, and additionally suggests independent positive influences of lipids (the long-term energy stores), with effects of glucose and glycogen (the short-term energy stores) tending to be negative. FA of paired traits was not associated with male mating success. Our study suggests that inclusion of physiological measures and genital traits in phenomenological studies of selection, which is rare, would be fruitful in other species.

Perceived social pressure not to experience negative emotion is linked to selective attention for negative information.

PubMed

Bastian, Brock; Pe, Madeline Lee; Kuppens, Peter

2017-02-01

Social norms and values may be important predictors of how people engage with and regulate their negative emotional experiences. Previous research has shown that social expectancies (the perceived social pressure not to feel negative emotion (NE)) exacerbate feelings of sadness. In the current research, we examined whether social expectancies may be linked to how people process emotional information. Using a modified classical flanker task involving emotional rather than non-emotional stimuli, we found that, for those who experienced low levels of NE, social expectancies were linked to the selective avoidance of negative emotional information. Those who experienced high levels of NE did not show a selective avoidance of negative emotional information. The findings suggest that, for people who experience many NEs, social expectancies may lead to discrepancies between how they think they ought to feel and the kind of emotional information they pay attention to.
Fibroblast growth factor 2 restrains Ras-driven proliferation of malignant cells by triggering RhoA-mediated senescence.

PubMed

Costa, Erico T; Forti, Fábio L; Matos, Tatiana G F; Dermargos, Alexandre; Nakano, Fábio; Salotti, Jacqueline; Rocha, Kátia M; Asprino, Paula F; Yoshihara, Celina K; Koga, Marianna M; Armelin, Hugo A

2008-08-01

Fibroblast growth factor 2 (FGF2) is considered to be a bona fide oncogenic factor, although results from our group and others call this into question. Here, we report that exogenous recombinant FGF2 irreversibly inhibits proliferation by inducing senescence in Ras-dependent malignant mouse cells, but not in immortalized nontumorigenic cell lines. We report the following findings in K-Ras-dependent malignant Y1 adrenocortical cells and H-Ras V12-transformed BALB-3T3 fibroblasts: (a) FGF2 inhibits clonal growth and tumor onset in nude and immunocompetent BALB/c mice, (b) FGF2 irreversibly blocks the cell cycle, and (c) FGF2 induces the senescence-associated beta-galactosidase with no accompanying signs of apoptosis or necrosis. The tyrosine kinase inhibitor PD173074 completely protected malignant cells from FGF2. In Y1 adrenal cells, reducing the constitutively high levels of K-Ras-GTP using the dominant-negative RasN17 mutant made cells resistant to FGF2 cytotoxicity. In addition, transfection of the dominant-negative RhoA-N19 into either Y1 or 3T3-B61 malignant cell lines yielded stable clonal transfectants that were unable to activate RhoA and were resistant to the FGF2 stress response. We conclude that in Ras-dependent malignant cells, FGF2 interacts with its cognate receptors to trigger a senescence-like process involving RhoA-GTP. Surprisingly, attempts to select FGF2-resistant cells from the Y1 and 3T3-B61 cell lines yielded only rare clones that (a) had lost the overexpressed ras oncogene, (b) were dependent on FGF2 for proliferation, and (c) were poorly tumorigenic. Thus, FGF2 exerted a strong negative selection that Ras-dependent malignant cells could rarely overcome.
Motion sickness: a negative reinforcement model.

PubMed

Bowins, Brad

2010-01-15

Theories pertaining to the "why" of motion sickness are in short supply relative to those detailing the "how." Considering the profoundly disturbing and dysfunctional symptoms of motion sickness, it is difficult to conceive of why this condition is so strongly biologically based in humans and most other mammalian and primate species. It is posited that motion sickness evolved as a potent negative reinforcement system designed to terminate motion involving sensory conflict or postural instability. During our evolution and that of many other species, motion of this type would have impaired evolutionary fitness via injury and/or signaling weakness and vulnerability to predators. The symptoms of motion sickness strongly motivate the individual to terminate the offending motion by early avoidance, cessation of movement, or removal of oneself from the source. The motion sickness negative reinforcement mechanism functions much like pain to strongly motivate evolutionary fitness preserving behavior. Alternative why theories focusing on the elimination of neurotoxins and the discouragement of motion programs yielding vestibular conflict suffer from several problems, foremost that neither can account for the rarity of motion sickness in infants and toddlers. The negative reinforcement model proposed here readily accounts for the absence of motion sickness in infants and toddlers, in that providing strong motivation to terminate aberrant motion does not make sense until a child is old enough to act on this motivation.
Is the compressibility positive or negative in a strongly-coupled dusty plasma?

NASA Astrophysics Data System (ADS)

Goree, John; Ruhunusiri, W. D. Suranga

2014-10-01

In dusty plasmas, dust particles are often strongly coupled with a large Coulomb coupling parameter Γ, while the electrons and ions that share the same volume are weakly coupled. In most substances, compressibility β must be positive; otherwise there would be an explosive instability. In a multicomponent plasma, however, one could entertain the idea that β for a single strongly coupled component could be negative, provided that the restoring force from charge separation overwhelms the destabilizing effect. Indeed, the compressibility for a strongly-coupled dust component is assumed to be negative in three theories we identified in the literature for dust acoustic waves. These theories use a multi-fluid model, with an OCP (one component plasma) or Yukawa-OCP approach for the dust fluid. We performed dusty plasma experiments designed to determine the value of the inverse compressibility β-1, and in particular its sign. We fit an experimentally measured dispersion relation to theory, with β-1 as a free parameter, taking into account the systematic errors in the experiment and model. We find that β-1 is either positive, or it has a negligibly small negative value, which is not in agreement with the assumptions of the OCP-based theories. Supported by NSF and NASA.
Pharmacological means of reducing human drug dependence: a selective and narrative review of the clinical literature

PubMed Central

Lin, Shih-Ku

2014-01-01

Substance abuse or addictive disorder is a global problem. A greater understanding of the associated changes in brain pathophysiology supports the notion that pharmacological treatments are part of the necessary treatment options. Craving is a core symptom of addictive disorder. It refers to a strong desire to use drugs again either to re-experience positive effects or to diminish negative experiences. Currently there are a number of medicines that are effective in the treatment of addictive disorders. These medications can either be for substitution (same pharmacological effect as the abused substance) or anticraving (decrease the craving of the abused substance). In this MEDLNE based review, specific compounds (naltrexone, acamprosate, topiramate, disulfiram, baclofen, N-acetylcysteine and bupropion) were selected that are known to diminish desire to use (anticraving effect) and that have been trialled for a number of different substance addictive disorders. Their therapeutic potential in clinical practice is discussed in light of their efficacy. PMID:23701272
Modeling multi-scale resource selection for bear rub trees in northwestern Montana

USGS Publications Warehouse

Morgan Henderson, Matthew J.; Hebblewhite, Mark; Mitchell, Michael S.; Stetz, Jeffrey B.; Kendall, Katherine C.; Carlson, Ross T.

2015-01-01

Both black (Ursus americanus) and grizzly bears (U. arctos) are known to rub on trees and other objects, producing a network of repeatedly used and identifiable rub sites. In 2012, we used a resource selection function to evaluate hypothesized relationships between locations of 887 bear rubs in northwestern Montana, USA, and elevation, slope angle, density of open roads and distance from areas of heightened plant-productivity likely containing forage for bears. Slope and density of open roads were negatively correlated with rub presence. No other covariates were supported as explanatory variables. We also hypothesized that bear rubs would be more strongly associated with closed roads and developed trails than with game trails. The frequencies of bear rubs on 30 paired segments of developed tracks and game trails were not different. Our results suggest bear rubs may be associated with bear travel routes, and support their use as “random” sampling devices for non-invasive spatial capture–recapture population monitoring.
Hoxa2 Selectively Enhances Meis Binding to Change a Branchial Arch Ground State

PubMed Central

Amin, Shilu; Donaldson, Ian J.; Zannino, Denise A.; Hensman, James; Rattray, Magnus; Losa, Marta; Spitz, François; Ladam, Franck; Sagerström, Charles; Bobola, Nicoletta

2015-01-01

Summary Hox transcription factors (TFs) are essential for vertebrate development, but how these evolutionary conserved proteins function in vivo remains unclear. Because Hox proteins have notoriously low binding specificity, they are believed to bind with cofactors, mainly homeodomain TFs Pbx and Meis, to select their specific targets. We mapped binding of Meis, Pbx, and Hoxa2 in the branchial arches, a series of segments in the developing vertebrate head. Meis occupancy is largely similar in Hox-positive and -negative arches. Hoxa2, which specifies second arch (IIBA) identity, recognizes a subset of Meis prebound sites that contain Hox motifs. Importantly, at these sites Meis binding is strongly increased. This enhanced Meis binding coincides with active enhancers, which are linked to genes highly expressed in the IIBA and regulated by Hoxa2. These findings show that Hoxa2 operates as a tissue-specific cofactor, enhancing Meis binding to specific sites that provide the IIBA with its anatomical identity. PMID:25640223
Functional asymmetry between the left and right human fusiform gyrus explored through electrical brain stimulation.

PubMed

Rangarajan, Vinitha; Parvizi, Josef

2016-03-01

The ventral temporal cortex (VTC) contains several areas with selective responses to words, numbers, faces, and objects as demonstrated by numerous human and primate imaging and electrophysiological studies. Our recent work using electrocorticography (ECoG) confirmed the presence of face-selective neuronal populations in the human fusiform gyrus (FG) in patients implanted with intracranial electrodes in either the left or right hemisphere. Electrical brain stimulation (EBS) disrupted the conscious perception of faces only when it was delivered in the right, but not left, FG. In contrast to our previous findings, here we report both negative and positive EBS effects in right and left FG, respectively. The presence of right hemisphere language dominance in the first, and strong left-handedness and poor language processing performance in the second case, provide indirect clues about the functional architecture of the human VTC in relation to hemispheric asymmetries in language processing and handedness. Copyright © 2015 Elsevier Ltd. All rights reserved.
[Dental loss and prosthetic replacement expectation: qualitative study].

PubMed

Silva, Maria Elisa de Souza E; Magalhães, Cláudia Silami de; Ferreira, Efigênia Ferreira E

2010-05-01

This qualitative research analyses the repercussions of total dental loss on people's quality of life. The Oral Health Impact Profile short-form (OHIP14) was applied to 50 volunteers, and after analyzing the results, 13 out of those 50, were selected to be individually interviewed in an opened questions script. The criteria to select these 13 people were: perception of the impact of mouth condition on quality of life measured by the score reached on OHIP. We tried to comprise the sample with a good variety, according to the profile of the initial sample. After analyzing people's statements, it was possible to verify that dental loss had strong negative consequences on people's life, like shame, difficulty to eat, impact on social relationship and feeling of not being complete. The possibility of having their teeth replaced generates some anxiety. Although being aware that wearing total prosthesis represents some sacrifices, people considered it worthwhile because the possibility of regaining the social pattern and the self-image is renewed.
Evolutionary dynamics of Newcastle disease virus

USGS Publications Warehouse

Miller, P.J.; Kim, L.M.; Ip, Hon S.; Afonso, C.L.

2009-01-01

A comprehensive dataset of NDV genome sequences was evaluated using bioinformatics to characterize the evolutionary forces affecting NDV genomes. Despite evidence of recombination in most genes, only one event in the fusion gene of genotype V viruses produced evolutionarily viable progenies. The codon-associated rate of change for the six NDV proteins revealed that the highest rate of change occurred at the fusion protein. All proteins were under strong purifying (negative) selection; the fusion protein displayed the highest number of amino acids under positive selection. Regardless of the phylogenetic grouping or the level of virulence, the cleavage site motif was highly conserved implying that mutations at this site that result in changes of virulence may not be favored. The coding sequence of the fusion gene and the genomes of viruses from wild birds displayed higher yearly rates of change in virulent viruses than in viruses of low virulence, suggesting that an increase in virulence may accelerate the rate of NDV evolution. ?? 2009 Elsevier Inc.
ACPA-Negative RA Consists of Two Genetically Distinct Subsets Based on RF Positivity in Japanese

PubMed Central

Terao, Chikashi; Ohmura, Koichiro; Ikari, Katsunori; Kochi, Yuta; Maruya, Etsuko; Katayama, Masaki; Yurugi, Kimiko; Shimada, Kota; Murasawa, Akira; Honjo, Shigeru; Takasugi, Kiyoshi; Matsuo, Keitaro; Tajima, Kazuo; Suzuki, Akari; Yamamoto, Kazuhiko; Momohara, Shigeki; Yamanaka, Hisashi; Yamada, Ryo; Saji, Hiroo; Matsuda, Fumihiko; Mimori, Tsuneyo

2012-01-01

HLA-DRB1, especially the shared epitope (SE), is strongly associated with rheumatoid arthritis (RA). However, recent studies have shown that SE is at most weakly associated with RA without anti-citrullinated peptide/protein antibody (ACPA). We have recently reported that ACPA-negative RA is associated with specific HLA-DRB1 alleles and diplotypes. Here, we attempted to detect genetically different subsets of ACPA-negative RA by classifying ACPA-negative RA patients into two groups based on their positivity for rheumatoid factor (RF). HLA-DRB1 genotyping data for totally 954 ACPA-negative RA patients and 2,008 healthy individuals in two independent sets were used. HLA-DRB1 allele and diplotype frequencies were compared among the ACPA-negative RF-positive RA patients, ACPA-negative RF-negative RA patients, and controls in each set. Combined results were also analyzed. A similar analysis was performed in 685 ACPA-positive RA patients classified according to their RF positivity. As a result, HLA-DRB1*04:05 and *09:01 showed strong associations with ACPA-negative RF-positive RA in the combined analysis (p = 8.8×10−6 and 0.0011, OR: 1.57 (1.28–1.91) and 1.37 (1.13–1.65), respectively). We also found that HLA-DR14 and the HLA-DR8 homozygote were associated with ACPA-negative RF-negative RA (p = 0.00022 and 0.00013, OR: 1.52 (1.21–1.89) and 3.08 (1.68–5.64), respectively). These association tendencies were found in each set. On the contrary, we could not detect any significant differences between ACPA-positive RA subsets. As a conclusion, ACPA-negative RA includes two genetically distinct subsets according to RF positivity in Japan, which display different associations with HLA-DRB1. ACPA-negative RF-positive RA is strongly associated with HLA-DRB1*04:05 and *09:01. ACPA-negative RF-negative RA is associated with DR14 and the HLA-DR8 homozygote. PMID:22792215
Chemical and colloidal aspects of collectorless flotation behavior of sulfide and non-sulfide minerals.

PubMed

Aghazadeh, Sajjad; Mousavinezhad, Seyed Kamal; Gharabaghi, Mahdi

2015-11-01

Flotation has been widely used for separation of valuable minerals from gangues based on their surface characterizations and differences in hydrophobicity on mineral surfaces. As hydrophobicity of minerals widely differs from each other, their separation by flotation will become easier. Collectors are chemical materials which are supposed to make selectively valuable minerals hydrophobic. In addition, there are some minerals which based on their surface and structural features are intrinsically hydrophobic. However, their hydrophobicities are not strong enough to be floatable in the flotation cell without collectors such as sulfide minerals, coal, stibnite, and so forth. To float these minerals in a flotation cell, their hydrophobicity should be increased in specific conditions. Various parameters including pH, Eh, size distribution, mill types, mineral types, ore characterization, and type of reaction in flotation cells affect the hydrophobicity of minerals. Surface analysis results show that when sulfide minerals experience specific flotation conditions, the reactions on the surface of these minerals increase the amount of sulfur on the surface. These phenomenons improve the hydrophobicity of these minerals due to strong hydrophobic feature of sulfurs. Collectorless flotation reduces chemical material consumption amount, increases flotation selectivity (grade increases), and affects the equipment quantities; however, it can also have negative effects. Some minerals with poor surface floatability can be increased by adding some ions to the flotation system. Depressing undesirable minerals in flotation is another application of collectorless flotation.
Distinction of Gram-positive and -negative bacteria using a colorimetric microbial viability assay based on the reduction of water-soluble tetrazolium salts with a selection medium.

PubMed

Tsukatani, Tadayuki; Suenaga, Hikaru; Higuchi, Tomoko; Shiga, Masanobu; Noguchi, Katsuya; Matsumoto, Kiyoshi

2011-01-01

Bacteria are fundamentally divided into two groups: Gram-positive and Gram-negative. Although the Gram stain and other techniques can be used to differentiate these groups, some issues exist with traditional approaches. In this study, we developed a method for differentiating Gram-positive and -negative bacteria using a colorimetric microbial viability assay based on the reduction of the tetrazolium salt {2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt} (WST-8) via 2-methyl-1,4-napthoquinone with a selection medium. We optimized the composition of the selection medium to allow the growth of Gram-negative bacteria while inhibiting the growth of Gram-positive bacteria. When the colorimetric viability assay was carried out in a selection medium containing 0.5µg/ml crystal violet, 5.0 µg/ml daptomycin, and 5.0µg/ml vancomycin, the reduction in WST-8 by Gram-positive bacteria was inhibited. On the other hand, Gram-negative bacteria produced WST-8-formazan in the selection medium. The proposed method was also applied to determine the Gram staining characteristics of bacteria isolated from various foodstuffs. There was good agreement between the results obtained using the present method and those obtained using a conventional staining method. These results suggest that the WST-8 colorimetric assay with selection medium is a useful technique for accurately differentiating Gram-positive and -negative bacteria.
Dynamic Association between Negative Affect and Alcohol Lapses following Alcohol Treatment

ERIC Educational Resources Information Center

Witkiewitz, Katie; Villarroel, Nadia Aracelliz

2009-01-01

Clinical research has found a strong association between negative affect and returning to alcohol use after a period of abstinence. Yet little is known about the probability of a lapse given a particular level of negative affect or whether there is a reciprocal relationship between negative affect and alcohol use across time. The goal of the…
BAPJ69-4A: a yeast two-hybrid strain for both positive and negative genetic selection.

PubMed

Shaffer, Hally Anne; Rood, Michael Kenneth; Kashlan, Badar; Chang, Eileen I-ling; Doyle, Donald Francis; Azizi, Bahareh

2012-10-01

Genetic selection systems, such as the yeast two-hybrid system, are efficient methods to detect protein-protein and protein-ligand interactions. These systems have been further developed to assess negative interactions, such as inhibition, using the URA3 genetic selection marker. Previously, chemical complementation was used to assess positive selection in Saccharomyces cerevisiae. In this work, a new S. cerevisiae strain, called BAPJ69-4A, containing three selective markers ADE2, HIS3, and URA3 as well as the lacZ gene controlled by Gal4 response elements, was developed and characterized using the retinoid X receptor (RXR) and its ligand 9-cis retinoic acid (9cRA). Further characterization was performed using RXR variants and the synthetic ligand LG335. To assess the functionality of the strain, RXR was compared to the parent strain PJ69-4A in adenine, histidine, and uracil selective media. In positive selection, associating partners that lead to cell growth were observed in all media in the presence of ligand, whereas partners that did not associate due to the absence of ligand displayed no growth. Conversely, in negative selection, partners that did not associate in 5-FOA medium did not display cell death due to the lack of expression of the URA3 gene. The creation of the BAPJ69-4A yeast strain provides a high-throughput selection system, called negative chemical complementation, which can be used for both positive and negative selection, providing a fast, powerful tool for discovering novel ligand receptor pairs for applications in drug discovery and protein engineering. Copyright © 2012 Elsevier B.V. All rights reserved.
What we talk about when we talk about access deficits

PubMed Central

Mirman, Daniel; Britt, Allison E.

2014-01-01

Semantic impairments have been divided into storage deficits, in which the semantic representations themselves are damaged, and access deficits, in which the representations are intact but access to them is impaired. The behavioural phenomena that have been associated with access deficits include sensitivity to cueing, sensitivity to presentation rate, performance inconsistency, negative serial position effects, sensitivity to number and strength of competitors, semantic blocking effects, disordered selection between strong and weak competitors, correlation between semantic deficits and executive function deficits and reduced word frequency effects. Four general accounts have been proposed for different subsets of these phenomena: abnormal refractoriness, too much activation, impaired competitive selection and deficits of semantic control. A combination of abnormal refractoriness and impaired competitive selection can account for most of the behavioural phenomena, but there remain several open questions. In particular, it remains unclear whether access deficits represent a single syndrome, a syndrome with multiple subtypes or a variable collection of phenomena, whether the underlying deficit is domain-general or domain-specific, whether it is owing to disorders of inhibition, activation or selection, and the nature of the connection (if any) between access phenomena in aphasia and in neurologically intact controls. Computational models offer a promising approach to answering these questions. PMID:24324232
Sex-dependent selection differentially shapes genetic variation on and off the guppy Y chromosome.

PubMed

Postma, Erik; Spyrou, Nicolle; Rollins, Lee Ann; Brooks, Robert C

2011-08-01

Because selection is often sex-dependent, alleles can have positive effects on fitness in one sex and negative effects in the other, resulting in intralocus sexual conflict. Evolutionary theory predicts that intralocus sexual conflict can drive the evolution of sex limitation, sex-linkage, and sex chromosome differentiation. However, evidence that sex-dependent selection results in sex-linkage is limited. Here, we formally partition the contribution of Y-linked and non-Y-linked quantitative genetic variation in coloration, tail, and body size of male guppies (Poecilia reticulata)-traits previously implicated as sexually antagonistic. We show that these traits are strongly genetically correlated, both on and off the Y chromosome, but that these correlations differ in sign and magnitude between both parts of the genome. As predicted, variation in attractiveness was found to be associated with the Y-linked, rather than with the non-Y-linked component of genetic variation in male ornamentation. These findings show how the evolution of Y-linkage may be able to resolve sexual conflict. More generally, they provide unique insight into how sex-specific selection has the potential to differentially shape the genetic architecture of fitness traits across different parts of the genome. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
Robust online tracking via adaptive samples selection with saliency detection

NASA Astrophysics Data System (ADS)

Yan, Jia; Chen, Xi; Zhu, QiuPing

2013-12-01

Online tracking has shown to be successful in tracking of previously unknown objects. However, there are two important factors which lead to drift problem of online tracking, the one is how to select the exact labeled samples even when the target locations are inaccurate, and the other is how to handle the confusors which have similar features with the target. In this article, we propose a robust online tracking algorithm with adaptive samples selection based on saliency detection to overcome the drift problem. To deal with the problem of degrading the classifiers using mis-aligned samples, we introduce the saliency detection method to our tracking problem. Saliency maps and the strong classifiers are combined to extract the most correct positive samples. Our approach employs a simple yet saliency detection algorithm based on image spectral residual analysis. Furthermore, instead of using the random patches as the negative samples, we propose a reasonable selection criterion, in which both the saliency confidence and similarity are considered with the benefits that confusors in the surrounding background are incorporated into the classifiers update process before the drift occurs. The tracking task is formulated as a binary classification via online boosting framework. Experiment results in several challenging video sequences demonstrate the accuracy and stability of our tracker.
The intake of selected foods by six-year-old Swedish children differs according to parental education and migration status.

PubMed

Säfsten, Eleonor; Nyberg, Gisela; Elinder, Liselotte Schäfer; Norman, Åsa; Patterson, Emma

2016-04-01

Little is known about how parental migration status may be associated with children's diets. We examined whether the intake of selected foods by six-year-old children differed according to their parents' migration status, taking education level into account. This study used pooled baseline data from two clustered randomised controlled trials of A Healthy School Start, conducted in municipalities of low-to-medium socio-economic status in Stockholm County, Sweden. The children's intake of selected healthy and unhealthy foods was reported by parents using the Eating and Physical Activity Questionnaire, and the children's height and weight were measured. Parental education and country of birth were self-reported. Data were available for 520 children. Low parental education was associated with significantly higher intakes of fruit, higher intakes of several unhealthy foods and lower intakes of vegetables. Children of parents born outside the Nordic region had higher intakes of all unhealthy foods as well as fruit and vegetables, even when adjusted for education. A negative association between high education and overweight was only seen in children of Nordic-born parents. Parental migration status was a strong predictor of the intake of selected foods and was a stronger predictor than parental education. ©2015 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.
The role of selective estrogen receptor modulators in the treatment of schizophrenia.

PubMed

Bratek, Agnieszka; Krysta, Krzysztof; Drzyzga, Karolina; Barańska, Justyna; Kucia, Krzysztof

2016-09-01

Gender differences in schizophrenia have been recognized for a long time and it has been widely accepted that sex steroid hormones, especially estradiol, are strongly attributed to this fact. Two hypotheses regarding estradiol action in psychoses gained special research attention - the estrogen protection hypothesis and hypoestrogenism hypothesis. A growing number of studies have shown benefits in augmenting antipsychotic treatment with estrogens or selective estrogen receptor modulators (SERM). This review is focused on the role of selective estrogen receptor modulators in the treatment of schizophrenic patients. In order to achieve this result PubMed was searched using the following terms: schizophrenia, raloxifene, humans. We reviewed only randomized, placebo-controlled studies. Raloxifene, a selective estrogen receptor modulator was identified as useful to improve negative, positive, and general psychopathological symptoms, and also cognitive functions. All reviewed studies indicated improvement in at least one studied domain. Augmentation with raloxifene was found to be a beneficial treatment strategy for chronic schizophrenia both in female and male patients, however potential side effects (a small increase in the risk of venous thromboembolism and endometrial cancer) should be carefully considered. SERMs could be an effective augmentation strategy in the treatment of both men women with schizophrenia, although further research efforts are needed to study potential long-term side effects.

Adaptation to fragmentation: evolutionary dynamics driven by human influences.

PubMed

Cheptou, Pierre-Olivier; Hargreaves, Anna L; Bonte, Dries; Jacquemyn, Hans

2017-01-19

Fragmentation-the process by which habitats are transformed into smaller patches isolated from each other-has been identified as a major threat for biodiversity. Fragmentation has well-established demographic and population genetic consequences, eroding genetic diversity and hindering gene flow among patches. However, fragmentation should also select on life history, both predictably through increased isolation, demographic stochasticity and edge effects, and more idiosyncratically via altered biotic interactions. While species have adapted to natural fragmentation, adaptation to anthropogenic fragmentation has received little attention. In this review, we address how and whether organisms might adapt to anthropogenic fragmentation. Drawing on selected case studies and evolutionary ecology models, we show that anthropogenic fragmentation can generate selection on traits at both the patch and landscape scale, and affect the adaptive potential of populations. We suggest that dispersal traits are likely to experience especially strong selection, as dispersal both enables migration among patches and increases the risk of landing in the inhospitable matrix surrounding them. We highlight that suites of associated traits are likely to evolve together. Importantly, we show that adaptation will not necessarily rescue populations from the negative effects of fragmentation, and may even exacerbate them, endangering the entire metapopulation.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'. © 2016 The Author(s).
Selective Attention and Inhibitory Deficits in ADHD: Does Subtype or Comorbidity Modulate Negative Priming Effects?

ERIC Educational Resources Information Center

Pritchard, Verena E.; Neumann, Ewald; Rucklidge, Julia J.

2008-01-01

Selective attention has durable consequences for behavior and neural activation. Negative priming (NP) effects are assumed to reflect a critical inhibitory component of selective attention. The performance of adolescents with Attention Deficit/Hyperactivity Disorder (ADHD) was assessed across two conceptually based NP tasks within a selective…
WHAT MAKES A GOOD PEDIATRIC TRANSPLANT LUNG: INSIGHTS FROM IN VIVO LUNG MORPHOMETRY WITH HYPERPOLARIZED 3HE MRI (WHAT MAKES A GOOD PEDIATRIC TRANSPLANT LUNG)

PubMed Central

Fishman, Emily F.; Quirk, James D.; Sweet, Stuart C.; Woods, Jason C.; Gierada, David S.; Conradi, Mark S.; Siegel, Marilyn J.; Yablonskiy, Dmitriy A.

2016-01-01

Background Obtaining information on transplanted lung microstructure is an important part of the current care for monitoring transplant recipients. However, until now this information was only available from invasive lung biopsy. The objective of this study was to evaluate the use of an innovative non-invasive technique in vivo lung morphometry with hyperpolarized 3He MRI - to characterize lung microstructure in the pediatric lung transplant population. This technique yields quantitative measurements of acinar airways’ (alveolar ducts and sacs) parameters, such as acinar airways radii and alveolar depth. Methods Six pediatric lung transplant recipients with cystic fibrosis underwent in vivo lung morphometry MRI, pulmonary function testing, and quantitative CT. Results We found a strong correlation between lung lifespan and alveolar depth - patients with more shallow alveoli were likely to have a negative outcome sooner than those with larger alveolar depth. Combining morphometric results with CT we also determined mean alveolar wall thickness and found substantial increases in this parameter in some patients that negatively correlated with DLCO. Conclusion In vivo lung morphometry uniquely provides previously unavailable information on lung microstructure that may be predictive of a negative outcome and has a potential to aid in lung selection for transplantation. PMID:28120553
Differential susceptibility to maternal expressed emotion in children with ADHD and their siblings? Investigating plasticity genes, prosocial and antisocial behaviour.

PubMed

Richards, Jennifer S; Hartman, Catharina A; Franke, Barbara; Hoekstra, Pieter J; Heslenfeld, Dirk J; Oosterlaan, Jaap; Arias Vásquez, Alejandro; Buitelaar, Jan K

2015-02-01

The differential susceptibility theory states that children differ in their susceptibility towards environmental experiences, partially due to plasticity genes. Individuals carrying specific variants in such genes will be more disadvantaged in negative but, conversely, more advantaged in positive environments. Understanding gene-environment interactions may help unravel the causal mechanisms involved in multifactorial psychiatric disorders such as Attention-Deficit/Hyperactivity Disorder (ADHD). The differential susceptibility theory was examined by investigating the presence of interaction effects between maternal expressed emotion (EE; warmth and criticism) and the solitary and combined effects of plasticity genes (DAT1, DRD4, 5-HTT) on prosocial and antisocial behaviour (measured with parent- and self-reports) in children with ADHD and their siblings (N = 366, M = 17.11 years, 74.9% male). Maternal warmth was positively associated with prosocial behaviour and negatively with antisocial behaviour, while maternal criticism was positively associated with antisocial behaviour and negatively with prosocial behaviour. No evidence of differential susceptibility was found. The current study found no evidence for differential susceptibility based on the selected plasticity genes, in spite of strong EE-behaviour associations. It is likely that additional factors play a role in the complex relationship between genes, environment and behaviour.
Richness and cover of nontimber economic plants along altitude in temperate Himalayan forest-use types.

PubMed

Tariq, Akash; Adnan, Muhammad; AbdElsalam, Naser M; Fouad, Hassan; Hussain, Kamran; Ullah, Riaz; Ullah, Ahsan

2014-01-01

Pakistani Himalaya stretches over a wide range of altitudinal gradients and supports high diversity of medicinal plants that are an important source for rural livelihood. Altitudinal effects on ground vegetation have already been indicated but ground vegetation is also under severe threat of grazing and over collection. The present study investigated the effect of altitude on medicinal plants abundance in both old-growth and derived woodland forests. Each of the five line transects was selected in old-growth and derived woodland forests. Each line transect consisted of four plots distributed at four altitudinal levels (2200, 2300, 2400, and 2500 m asl). Species richness under derived woodland had shown strong negative correlation (r = -0.95) with altitude while it was found to be nonsignificant under old-growth. Cover of most of the species such as Veronica laxa (r = -0.95, P ≤ 0.05) had shown significant negative correlation with altitude under derived woodland. Cover abundance of some species like Valeriana jatamansi and Viola canescens has also shown significant negative correlation under old-growth forest. Derived woodland can decrease the cover abundance of valuable medicinal plants towards extension at higher altitudes. Thus, protection of the derived woodland could serve as a tool for the improvement of rural livelihood and ecological restoration.
Sexually antagonistic genetic variance for fitness in an ancestral and a novel environment.

PubMed

Delcourt, Matthieu; Blows, Mark W; Rundle, Howard D

2009-06-07

The intersex genetic correlation for fitness , a standardized measure of the degree to which male and female fitness covary genetically, has consequences for important evolutionary processes, but few estimates are available and none have explored how it changes with environment. Using a half-sibling breeding design, we estimated the genetic (co)variance matrix (G) for male and female fitness, and the resulting , in Drosophila serrata. Our estimates were performed in two environments: the laboratory yeast food to which the population was well adapted and a novel corn food. The major axis of genetic variation for fitness in the two environments, accounting for 51.3 per cent of the total genetic variation, was significant and revealed a strong signal of sexual antagonism, loading negatively in both environments on males but positively on females. Consequently, estimates of were negative in both environments (-0.34 and -0.73, respectively), indicating that the majority of genetic variance segregating in this population has contrasting effects on male and female fitness. The possible strengthening of the negative in this novel environment may be a consequence of no history of selection for amelioration of sexual conflict. Additional studies from a diverse range of novel environments will be needed to determine the generality of this finding.
The Integrative Effects of Cognitive Reappraisal on Negative Affect: Associated Changes in Secretory Immunoglobulin A, Unpleasantness and ERP Activity

PubMed Central

Zhang, Wencai; Li, Fan; Qin, Shaozheng; Luo, Jing

2012-01-01

Although the regulatory role of cognitive reappraisal in negative emotional responses is widely recognized, this reappraisal's effect on acute saliva secretory immunoglobulin A (SIgA), as well as the relationships among affective, immunological, and event-related potential (ERP) changes, remains unclear. In this study, we selected only people with low positive coping scores (PCSs) as measured by the Trait Coping Style Questionnaire to avoid confounding by intrinsic coping styles. First, we found that the acute stress of viewing unpleasant pictures consistently decreased SIgA concentration and secretion rate, increased perceptions of unpleasantness and amplitude of late positive potentials (LPPs) between 200–300 ms and 400–1000 ms. After participants used cognitive reappraisal, their SIgA concentration and secretion rate significantly increased and their unpleasantness and LPP amplitudes significantly decreased compared with a control condition. Second, we found a significantly positive correlation between the increases in SIgA and the decreases in unpleasantness and a significantly negative correlation between the increases in SIgA and the increases in LPP across the two groups. This study is the first to demonstrate that cognitive reappraisal reverses the decrease of SIgA. In addition, it revealed strong correlations among affective, SIgA and electrophysiological changes with convergent multilevel evidence. PMID:22319586
Richness and Cover of Nontimber Economic Plants along Altitude in Temperate Himalayan Forest-Use Types

PubMed Central

Tariq, Akash; Adnan, Muhammad; AbdElsalam, Naser M.; Fouad, Hassan; Hussain, Kamran; Ullah, Ahsan

2014-01-01

Pakistani Himalaya stretches over a wide range of altitudinal gradients and supports high diversity of medicinal plants that are an important source for rural livelihood. Altitudinal effects on ground vegetation have already been indicated but ground vegetation is also under severe threat of grazing and over collection. The present study investigated the effect of altitude on medicinal plants abundance in both old-growth and derived woodland forests. Each of the five line transects was selected in old-growth and derived woodland forests. Each line transect consisted of four plots distributed at four altitudinal levels (2200, 2300, 2400, and 2500 m asl). Species richness under derived woodland had shown strong negative correlation (r = −0.95) with altitude while it was found to be nonsignificant under old-growth. Cover of most of the species such as Veronica laxa (r = −0.95, P ≤ 0.05) had shown significant negative correlation with altitude under derived woodland. Cover abundance of some species like Valeriana jatamansi and Viola canescens has also shown significant negative correlation under old-growth forest. Derived woodland can decrease the cover abundance of valuable medicinal plants towards extension at higher altitudes. Thus, protection of the derived woodland could serve as a tool for the improvement of rural livelihood and ecological restoration. PMID:25032237
Differential Susceptibility to Maternal Expressed Emotion in Children with ADHD and their Siblings? Investigating Plasticity Genes, Prosocial and Antisocial Behaviour

PubMed Central

Richards, Jennifer S.; Hartman, Catharina A.; Franke, Barbara; Hoekstra, Pieter J.; Heslenfeld, Dirk J.; Oosterlaan, Jaap; Vásquez, Alejandro Arias; Buitelaar, Jan K.

2014-01-01

Background The differential susceptibility theory states that children differ in their susceptibility towards environmental experiences, partially due to plasticity genes. Individuals carrying specific variants in such genes will be more disadvantaged in negative but, conversely, more advantageous in positive environments. Understanding gene-environment interactions may help unravel the causal mechanisms involved in multifactorial psychiatric disorders such as Attention-Deficit/Hyperactivity Disorder (ADHD). Methods The differential susceptibility theory was examined by investigating the presence of interaction effects between maternal expressed emotion (EE; warmth and criticism) and the solitary and combined effects of plasticity genes (DAT1, DRD4, 5-HTT) on prosocial and antisocial behaviour (measured with parent- and self-reports) in children with ADHD and their siblings (N=366, M=17.11 years, 74.9 % male). Results Maternal warmth was positively associated with prosocial behaviour and negatively with antisocial behaviour, while maternal criticism was positively associated with antisocial behaviour and negatively with prosocial behaviour. No evidence of differential susceptibility was found. Conclusions The current study found no evidence for differential susceptibility based on the selected plasticity genes, in spite of strong EE-behaviour associations. It is likely that additional factors play a role in the complex relationship between genes, environment and behaviour. PMID:24929324
Simple method of DNA stretching on glass substrate for fluorescence image and spectroscopy

NASA Astrophysics Data System (ADS)

Neupane, Guru P.; Dhakal, Krishna P.; Lee, Hyunsoo; Guthold, Martin; Joseph, Vincent S.; Hong, Jong-Dal; Kim, Jeongyong

2013-05-01

Study of biological molecule DNA has contributed to developing many breaking thoughts and wide applications in multidisciplinary fields, such as genomic, medical, sensing and forensic fields. Stretching of DNA molecules is an important supportive tool for AFM or spectroscopic studies of DNA in a single molecular level. In this article, we established a simple method of DNA stretching (to its full length) that occurred on a rotating negatively-charged surface of glass substrate. The isolation of a single DNA molecule was attained by the two competitive forces on DNA molecules, that is, the electrostatic attraction developed between the positively charged YOYO-1 stained DNA and the negatively charged substrate, and the centrifugal force of the rotating substrate, which separates the DNA aggregates into the single molecule. Density of stretched DNA molecules was controlled by selecting the specific parameters such as spinning time and rates, loading volume of DNA-dye complex solution etc. The atomic force microscopy image exhibited a single DNA molecule on the negatively-charged substrate in an isolated state. Further, the photoluminescence spectra of a single DNA molecule stained with YOYO-1 were achieved using the method developed in the present study, which is strongly believed to effectively support the spectroscopic analysis of DNA in a single molecular level.
Selection and paucity of phylogenetic signal challenge the utility of alpha-tubulin in reconstruction of evolutionary history of free-living litostomateans (Protista, Ciliophora).

PubMed

Rajter, Ľubomír; Vďačný, Peter

2018-05-12

The class Litostomatea represents a highly diverse but monophyletic group, uniting both free-living and endosymbiotic ciliates. Ribosomal RNA genes and ITS-region sequences helped to recognize and define the main litostomatean lineages, but did not provide enough phylogenetic signal to unambiguously resolve their interrelationships. In this study, we attempted to improve the resolution among main free-living predatory lineages by adding the gene coding for alpha-tubulin. However, our phylogenetic analyses challenged the performance of alpha-tubulin in reconstruction of evolutionary history of free-living litostomateans. We identified several mutually interconnected problems associated with the ciliate alpha-tubulin gene: the paucity of phylogenetic signal, molecular homoplasies and non-neutral evolution. Positive selection may generate molecular homoplasies (parallel evolution), while negative selection may cause a small number of changes and hence little phylogenetic informativness. Both problems were encountered in nucleotide and amino acid alpha-tubulin alignments, indicating an action of various selective pressures. Taking into account the involvement of alpha-tubulin in many essential biological processes, this protein could be so strongly affected by purifying selection that it even might have become an inappropriate molecular marker for reconstruction of phylogenetic relationships. Therefore, a great caution should be paid when tubulin genes are included in phylogenetic and/or phylogenomic analyses. Copyright © 2018 Elsevier Inc. All rights reserved.
SIMS of Organic Materials—Interface Location in Argon Gas Cluster Depth Profiles Using Negative Secondary Ions

NASA Astrophysics Data System (ADS)

Havelund, R.; Seah, M. P.; Tiddia, M.; Gilmore, I. S.

2018-02-01

A procedure has been established to define the interface position in depth profiles accurately when using secondary ion mass spectrometry and the negative secondary ions. The interface position varies strongly with the extent of the matrix effect and so depends on the secondary ion measured. Intensity profiles have been measured at both fluorenylmethyloxycarbonyl-uc(l)-pentafluorophenylalanine (FMOC) to Irganox 1010 and Irganox 1010 to FMOC interfaces for many secondary ions. These profiles show separations of the two interfaces that vary over some 10 nm depending on the secondary ion selected. The shapes of these profiles are strongly governed by matrix effects, slightly weakened by a long wavelength roughening. The matrix effects are separately measured using homogeneous, known mixtures of these two materials. Removal of the matrix and roughening effects give consistent compositional profiles for all ions that are described by an integrated exponentially modified Gaussian (EMG) profile. Use of a simple integrated Gaussian may lead to significant errors. The average interface positions in the compositional profiles are determined to standard uncertainties of 0.19 and 0.14 nm, respectively, using the integrated EMG function. Alternatively, and more simply, it is shown that interface positions and profiles may be deduced from data for several secondary ions with measured matrix factors by simply extrapolating the result to Ξ = 0. Care must be taken in quoting interface resolutions since those measured for predominantly Gaussian interfaces with Ξ above or below zero, without correction, appear significantly better than the true resolution.
Ab initio theory of spin-orbit coupling for quantum bits in diamond exhibiting dynamic Jahn-Teller effect

NASA Astrophysics Data System (ADS)

Gali, Adam; Thiering, Gergő

Dopants in solids are promising candidates for implementations of quantum bits for quantum computing. In particular, the high-spin negatively charged nitrogen-vacancy defect (NV) in diamond has become a leading contender in solid-state quantum information processing. The initialization and readout of the spin is based on the spin-selective decay of the photo-excited electron to the ground state which is mediated by spin-orbit coupling between excited states states and phonons. Generally, the spin-orbit coupling plays a crucial role in the optical spinpolarization and readout of NV quantum bit (qubit) and alike. Strong electron-phonon coupling in dynamic Jahn-Teller (DJT) systems can substantially influence the effective strength of spin-orbit coupling. Here we show by ab initio supercell density functional theory (DFT) calculations that the intrinsic spin-orbit coupling is strongly damped by DJT effect in the triplet excited state that has a consequence on the rate of non-radiative decay. This theory is applied to the ground state of silicon-vacancy (SiV) and germanium-vacancy (GeV) centers in their negatively charged state that can also act like qubits. We show that the intrinsic spin-orbit coupling in SiV and GeV centers is in the 100 GHz region, in contrast to the NV center of 10 GHz region. Our results provide deep insight in the nature of SiV and GeV qubits in diamond. EU FP7 DIADEMS project (Contract No. 611143).
A systematic review of the diagnostic performance of orthopedic physical examination tests of the hip

PubMed Central

2013-01-01

Background Previous reviews of the diagnostic performances of physical tests of the hip in orthopedics have drawn limited conclusions because of the low to moderate quality of primary studies published in the literature. This systematic review aims to build on these reviews by assessing a broad range of hip pathologies, and employing a more selective approach to the inclusion of studies in order to accurately gauge diagnostic performance for the purposes of making recommendations for clinical practice and future research. It specifically identifies tests which demonstrate strong and moderate diagnostic performance. Methods A systematic search of Medline, Embase, Embase Classic and CINAHL was conducted to identify studies of hip tests. Our selection criteria included an analysis of internal and external validity. We reported diagnostic performance in terms of sensitivity, specificity, predictive values and likelihood ratios. Likelihood ratios were used to identify tests with strong and moderate diagnostic utility. Results Only a small proportion of tests reported in the literature have been assessed in methodologically valid primary studies. 16 studies were included in our review, producing 56 independent test-pathology combinations. Two tests demonstrated strong clinical utility, the patellar-pubic percussion test for excluding radiologically occult hip fractures (negative LR 0.05, 95% Confidence Interval [CI] 0.03-0.08) and the hip abduction sign for diagnosing sarcoglycanopathies in patients with known muscular dystrophies (positive LR 34.29, 95% CI 10.97-122.30). Fifteen tests demonstrated moderate diagnostic utility for diagnosing and/or excluding hip fractures, symptomatic osteoarthritis and loosening of components post-total hip arthroplasty. Conclusions We have identified a number of tests demonstrating strong and moderate diagnostic performance. These findings must be viewed with caution as there are concerns over the methodological quality of the primary studies from which we have extracted our data. Future studies should recruit larger, representative populations and allow for the construction of complete 2×2 contingency tables. PMID:23987589
A systematic review of the diagnostic performance of orthopedic physical examination tests of the hip.

PubMed

Rahman, Labib Ataur; Adie, Sam; Naylor, Justine Maree; Mittal, Rajat; So, Sarah; Harris, Ian Andrew

2013-08-30

Previous reviews of the diagnostic performances of physical tests of the hip in orthopedics have drawn limited conclusions because of the low to moderate quality of primary studies published in the literature. This systematic review aims to build on these reviews by assessing a broad range of hip pathologies, and employing a more selective approach to the inclusion of studies in order to accurately gauge diagnostic performance for the purposes of making recommendations for clinical practice and future research. It specifically identifies tests which demonstrate strong and moderate diagnostic performance. A systematic search of Medline, Embase, Embase Classic and CINAHL was conducted to identify studies of hip tests. Our selection criteria included an analysis of internal and external validity. We reported diagnostic performance in terms of sensitivity, specificity, predictive values and likelihood ratios. Likelihood ratios were used to identify tests with strong and moderate diagnostic utility. Only a small proportion of tests reported in the literature have been assessed in methodologically valid primary studies. 16 studies were included in our review, producing 56 independent test-pathology combinations. Two tests demonstrated strong clinical utility, the patellar-pubic percussion test for excluding radiologically occult hip fractures (negative LR 0.05, 95% Confidence Interval [CI] 0.03-0.08) and the hip abduction sign for diagnosing sarcoglycanopathies in patients with known muscular dystrophies (positive LR 34.29, 95% CI 10.97-122.30). Fifteen tests demonstrated moderate diagnostic utility for diagnosing and/or excluding hip fractures, symptomatic osteoarthritis and loosening of components post-total hip arthroplasty. We have identified a number of tests demonstrating strong and moderate diagnostic performance. These findings must be viewed with caution as there are concerns over the methodological quality of the primary studies from which we have extracted our data. Future studies should recruit larger, representative populations and allow for the construction of complete 2×2 contingency tables.
Looking on the bright side: biased attention and the human serotonin transporter gene.

PubMed

Fox, Elaine; Ridgewell, Anna; Ashwin, Chris

2009-05-22

Humans differ in terms of biased attention for emotional stimuli and these biases can confer differential resilience and vulnerability to emotional disorders. Selective processing of positive emotional information, for example, is associated with enhanced sociability and well-being while a bias for negative material is associated with neuroticism and anxiety. A tendency to selectively avoid negative material might also be associated with mental health and well-being. The neurobiological mechanisms underlying these cognitive phenotypes are currently unknown. Here we show for the first time that allelic variation in the promotor region of the serotonin transporter gene (5-HTTLPR) is associated with differential biases for positive and negative affective pictures. Individuals homozygous for the long allele (LL) showed a marked bias to selectively process positive affective material alongside selective avoidance of negative affective material. This potentially protective pattern was absent among individuals carrying the short allele (S or SL). Thus, allelic variation on a common genetic polymorphism was associated with the tendency to selectively process positive or negative information. The current study is important in demonstrating a genotype-related alteration in a well-established processing bias, which is a known risk factor in determining both resilience and vulnerability to emotional disorders.
Transport across the outer membrane porin of mycolic acid containing actinomycetales: Nocardia farcinica.

PubMed

Singh, Pratik Raj; Bajaj, Harsha; Benz, Roland; Winterhalter, Mathias; Mahendran, Kozhinjampara R

2015-02-01

The role of the outer-membrane channel from a mycolic acid containing Gram-positive bacteria Nocardia farcinica, which forms a hydrophilic pathway across the cell wall, was characterized. Single channel electrophysiology measurements and liposome swelling assays revealed the permeation of hydrophilic solutes including sugars, amino acids and antibiotics. The cation selective N. farcinica channel exhibited strong interaction with the positively charged antibiotics; amikacin and kanamycin, and surprisingly also with the negatively charged ertapenem. Voltage dependent kinetics of amikacin and kanamycin interactions were studied to distinguish binding from translocation. Moreover, the importance of charged residues inside the channel was investigated using mutational studies that revealed rate limiting interactions during the permeation. Copyright © 2014 Elsevier B.V. All rights reserved.
A quantitative measure of chirality inside nucleic acid databank.

PubMed

Pietropaolo, Adriana; Parrinello, Michele

2011-08-01

We show the capability of a chirality index (Pietropaolo et al., Proteins 2008;70:667-677) to investigate nucleic acid structures because of its high sensitivity to helical conformations. By analyzing selected structures of DNA and RNA, we have found that sequences rich in cytosine and guanine have a tendency to left-handed chirality, in contrast to regions rich in adenine or thymine which show strong negative, right-handed, chirality values. We also analyze RNA structures, where specific loops and hairpin motifs are characterized by a well-defined chirality value. We find that in nucleosome the chirality is exalted, whereas in ribosome it is reduced. Our results illustrate the sensitivity of this descriptor for nucleic acid conformations. Copyright © 2011 Wiley-Liss, Inc.
Selection of forages by timor deer (cervus timorensis blainville) in menjangan island, bali

NASA Astrophysics Data System (ADS)

Ketut Ginantra, I.; Bagus Made Suaskara, Ida; Ketut Muksin, I.

2018-03-01

This study was conducted to determine the selection of forages plants by Timor deer (Cervus timorensis) on Menjangan Island and its relation to the availability, chemical and physical properties of feed plants. The study was conducted in July-September 2016 in savanna and monsoon forest habitats. The availability of habitat feed plants in the habitat was determined by the quadrat method, and the species of plant eaten by Timor deer was determined through the microhistological analysis of the fecal sample. The food selection index is determine by the Ivlev index. Energy contents of forages plants by bomb calorimeter apparatus, crude protein analyzed by Semi-Micro Kjeldahl technique, NDF, ADF and lignin levels refer to the method of Goering and Van Soest. Mineral content of calcium (Ca) and phosphorus (P) by using atomic absorption spectrophotometer. Determination of tannin content with Folin Denish reaction. Physical properties determine are water regain capacity and water solubility. The relationship between availability with the utilization of plants by Timor deer was analyzed with the similarity index. Multiple regression statistic to test the relationship between index selection with nutritional value factor and physical characteristic of plant species. The result showed that Timor deer selected 32 plants species of graminoids, forbs and woody plants. Feeding selection of Timor deer is strongly influenced by the availability of forage plants in habitat. The feeding selection was significantly influenced by three predictor variables i.e. positive nutritional value is crude protein and negative nutritional value were lignin and tannins. Selection of forage plant Timor deer is positively correlated with the physical properties of feed plants.
Mood effects on attitude judgments: independent effects of mood before and after message elaboration.

PubMed

Bless, H; Mackie, D M; Schwarz, N

1992-10-01

This study investigated the independent effects of induced mood on the encoding of persuasive messages and on the assessment of attitude judgments. In Experiment 1, positive or negative mood was induced either before the encoding of a counterattitudinal message or before the assessment of attitude judgments. When mood was induced before message presentation, Ss in a bad mood were more persuaded by strong than by weak arguments, whereas Ss in a good mood were equally persuaded by strong and by weak arguments. When Ss encoded the message in a neutral mood, however, the advantage of strong over weak arguments was more pronounced when Ss were in a good rather than in a bad mood at the time of attitude assessment. In Experiment 2, Ss exposed to a counterattitudinal message composed of either strong or weak arguments formed either a global evaluation or a detailed representation of the message. Positive, negative, or neutral mood was then induced. Ss in a good mood were most likely and Ss in a negative mood least likely to base their reported attitudes on global evaluations.

Detecting Past Positive Selection through Ongoing Negative Selection

PubMed Central

Bazykin, Georgii A.; Kondrashov, Alexey S.

2011-01-01

Detecting positive selection is a challenging task. We propose a method for detecting past positive selection through ongoing negative selection, based on comparison of the parameters of intraspecies polymorphism at functionally important and selectively neutral sites where a nucleotide substitution of the same kind occurred recently. Reduced occurrence of recently replaced ancestral alleles at functionally important sites indicates that negative selection currently acts against these alleles and, therefore, that their replacements were driven by positive selection. Application of this method to the Drosophila melanogaster lineage shows that the fraction of adaptive amino acid replacements remained approximately 0.5 for a long time. In the Homo sapiens lineage, however, this fraction drops from approximately 0.5 before the Ponginae–Homininae divergence to approximately 0 after it. The proposed method is based on essentially the same data as the McDonald–Kreitman test but is free from some of its limitations, which may open new opportunities, especially when many genotypes within a species are known. PMID:21859804
The complexity of selection at the major primate beta-defensin locus.

PubMed

Semple, Colin A M; Maxwell, Alison; Gautier, Philippe; Kilanowski, Fiona M; Eastwood, Hayden; Barran, Perdita E; Dorin, Julia R

2005-05-18

We have examined the evolution of the genes at the major human beta-defensin locus and the orthologous loci in a range of other primates and mouse. For the first time these data allow us to examine selective episodes in the more recent evolutionary history of this locus as well as the ancient past. We have used a combination of maximum likelihood based tests and a maximum parsimony based sliding window approach to give a detailed view of the varying modes of selection operating at this locus. We provide evidence for strong positive selection soon after the duplication of these genes within an ancestral mammalian genome. Consequently variable selective pressures have acted on beta-defensin genes in different evolutionary lineages, with episodes both of negative, and more rarely positive selection, during the divergence of primates. Positive selection appears to have been more common in the rodent lineage, accompanying the birth of novel, rodent-specific beta-defensin genes. These observations allow a fuller understanding of the evolution of mammalian innate immunity. In both the rodent and primate lineages, sites in the second exon have been subject to positive selection and by implication are important in functional diversity. A small number of sites in the mature human peptides were found to have undergone repeated episodes of selection in different primate lineages. Particular sites were consistently implicated by multiple methods at positions throughout the mature peptides. These sites are clustered at positions predicted to be important for the specificity of the antimicrobial or chemoattractant properties of beta-defensins. Surprisingly, sites within the prepropeptide region were also implicated as being subject to significant positive selection, suggesting previously unappreciated functional significance for this region. Identification of these putatively functional sites has important implications for our understanding of beta-defensin function and for novel antibiotic design.
Prevalence and risk factors of female sexual dysfunction among healthcare personnel in Malaysia.

PubMed

Grewal, Gurdeep Singh; Gill, Jesjeet Singh; Sidi, Hatta; Gurpreet, Kaur; Jambunathan, Stephen Thevanathan; Suffee, Nusrat J; Midin, Marhani; Nik Jaafar, Nik Ruzyanei; Das, Srijit

2014-01-01

To determine the prevalence and risk factors of female sexual dysfunction (FSD) among healthcare personnel in selected healthcare facilities in Malaysia. This was a cross-sectional study carried out at three large healthcare facilities that were selected by convenience sampling. Within each facility, stratified random sampling was used to select suitable candidates to participate in the study (n=201). Validated questionnaires were used to assess depression, anxiety, sexual function in women and erectile dysfunction (ED) in their partners. The prevalence of FSD was 5.5%. Women with sexual dysfunction were more likely to be married longer (OR=4.08; 95% CI; 1.15-4.50), had lower frequency of sexual intercourse (OR=5.00; 95% C; 1.05-23.76) and had a spouse with ED (OR=24.35; 95% CI; 4.55-130.37). Multivariate analysis showed that ED was the strongest predictor for FSD (AOR=27.30; 95% CI; 4.706-159.08). One in eighteen female healthcare personnel suffered from FSD and presence of ED in the partner strongly impacted her sexual function, negatively. The findings highlight the importance of including the male partner in clinical assessment of FSD. Copyright © 2014 Elsevier Inc. All rights reserved.
Plant Rhizosphere Selection of Plasmodiophorid Lineages from Bulk Soil: The Importance of “Hidden” Diversity

PubMed Central

Bass, David; van der Gast, Christopher; Thomson, Serena; Neuhauser, Sigrid; Hilton, Sally; Bending, Gary D.

2018-01-01

Microbial communities closely associated with the rhizosphere can have strong positive and negative impacts on plant health and growth. We used a group-specific amplicon approach to investigate local scale drivers in the diversity and distribution of plasmodiophorids in rhizosphere/root and bulk soil samples from oilseed rape (OSR) and wheat agri-systems. Plasmodiophorids are plant- and stramenopile-associated protists including well known plant pathogens as well as symptomless endobiotic species. We detected 28 plasmodiophorid lineages (OTUs), many of them novel, and showed that plasmodiophorid communities were highly dissimilar and significantly divergent between wheat and OSR rhizospheres and between rhizosphere and bulk soil samples. Bulk soil communities were not significantly different between OSR and wheat systems. Wheat and OSR rhizospheres selected for different plasmodiophorid lineages. An OTU corresponding to Spongospora nasturtii was positively selected in the OSR rhizosphere, as were two genetically distinct OTUs. Two novel lineages related to Sorosphaerula veronicae were significantly associated with wheat rhizosphere samples, indicating unknown plant-protist relationships. We show that group-targeted eDNA approaches to microbial symbiont-host ecology reveal significant novel diversity and enable inference of differential activity and potential interactions between sequence types, as well as their presence. PMID:29503632
Resolving the conundrum of inbreeding depression but no inbreeding avoidance: Estimating sex-specific selection on inbreeding by song sparrows (Melospiza melodia).

PubMed

Reid, Jane M; Arcese, Peter; Bocedi, Greta; Duthie, A Bradley; Wolak, Matthew E; Keller, Lukas F

2015-11-01

Inbreeding avoidance among interacting females and males is not always observed despite inbreeding depression in offspring fitness, creating an apparent "inbreeding paradox." This paradox could be resolved if selection against inbreeding was in fact weak, despite inbreeding depression. However, the net magnitude and direction of selection on the degree to which females and males inbreed by pairing with relatives has not been explicitly estimated. We used long-term pedigree data to estimate phenotypic selection gradients on the degree of inbreeding that female and male song sparrows (Melospiza melodia) expressed by forming socially persistent breeding pairs with relatives. Fitness was measured as the total numbers of offspring and grand offspring contributed to the population, and as corresponding expected numbers of identical-by-descent allele copies, thereby accounting for variation in offspring survival, reproduction, and relatedness associated with variation in parental inbreeding. Estimated selection gradients on the degree to which individuals paired with relatives were weakly positive in females, but negative in males that formed at least one socially persistent pairing. However, males that paired had higher mean fitness than males that remained socially unpaired. These analyses suggest that net selection against inbreeding may be weak in both sexes despite strong inbreeding depression, thereby resolving the "inbreeding paradox." © 2015 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.
Moderating Effects of a Craving Intervention on the Relation between Negative Mood and Heavy Drinking Following Treatment for Alcohol Dependence

ERIC Educational Resources Information Center

Witkiewitz, Katie; Bowen, Sarah; Donovan, Dennis M.

2011-01-01

Objective: Negative affect is a significant predictor of alcohol relapse, and the relation between negative affect and drinking has been shown to be strongly mediated by alcohol craving. Thus, targeting craving during treatment could potentially attenuate the relation between negative affect and drinking. Method: The current study is a secondary…
Frequency dependence limits divergent evolution by favouring rare immigrants over residents.

PubMed

Bolnick, Daniel I; Stutz, William E

2017-06-08

Two distinct forms of natural selection promote adaptive biological diversity. Divergent selection occurs when different environments favour different phenotypes, leading to increased differences between populations. Negative frequency-dependent selection occurs when rare variants within a population are favoured over common ones, increasing diversity within populations. These two diversifying forces promote genetic variation at different spatial scales, and may act in opposition, but their relative effects remain unclear because they are rarely measured concurrently. Here we show that negative frequency-dependent selection within populations can favor rare immigrants over locally adapted residents. We reciprocally transplanted lake and stream ecotypes of threespine stickleback into lake and stream habitats, while manipulating the relative abundance of residents versus immigrants. We found negative frequency-dependence: survival was highest for the locally rare ecotype, rather than natives. Also, individuals with locally rare major histocompatibility complex (MHC) class IIb genotypes were infected by fewer parasites. This negative frequency-dependent selection will tend to favour rare immigrants over common residents, amplifying the effect of migration and undermining the efficacy of divergent natural selection to drive population differences. The only signal of divergent selection was a tendency for foreign fish to have higher parasite loads than residents, after controlling for MHC genotype rarity. Frequency-dependent ecological interactions have long been thought to promote speciation. Our results suggest a more nuanced view in which negative frequency dependence alters the fate of migrants to promote or constrain evolutionary divergence between populations.
A Newtonian approach to extraordinarily strong negative refraction.

PubMed

Yoon, Hosang; Yeung, Kitty Y M; Umansky, Vladimir; Ham, Donhee

2012-08-02

Metamaterials with negative refractive indices can manipulate electromagnetic waves in unusual ways, and can be used to achieve, for example, sub-diffraction-limit focusing, the bending of light in the 'wrong' direction, and reversed Doppler and Cerenkov effects. These counterintuitive and technologically useful behaviours have spurred considerable efforts to synthesize a broad array of negative-index metamaterials with engineered electric, magnetic or optical properties. Here we demonstrate another route to negative refraction by exploiting the inertia of electrons in semiconductor two-dimensional electron gases, collectively accelerated by electromagnetic waves according to Newton's second law of motion, where this acceleration effect manifests as kinetic inductance. Using kinetic inductance to attain negative refraction was theoretically proposed for three-dimensional metallic nanoparticles and seen experimentally with surface plasmons on the surface of a three-dimensional metal. The two-dimensional electron gas that we use at cryogenic temperatures has a larger kinetic inductance than three-dimensional metals, leading to extraordinarily strong negative refraction at gigahertz frequencies, with an index as large as -700. This pronounced negative refractive index and the corresponding reduction in the effective wavelength opens a path to miniaturization in the science and technology of negative refraction.
Freeze or flee? Negative stimuli elicit selective responding.

PubMed

Estes, Zachary; Verges, Michelle

2008-08-01

Humans preferentially attend to negative stimuli. A consequence of this automatic vigilance for negative valence is that negative words elicit slower responses than neutral or positive words on a host of cognitive tasks. Some researchers have speculated that negative stimuli elicit a general suppression of motor activity, akin to the freezing response exhibited by animals under threat. Alternatively, we suggest that negative stimuli only elicit slowed responding on tasks for which stimulus valence is irrelevant for responding. To discriminate between these motor suppression and response-relevance hypotheses, we elicited both lexical decisions and valence judgments of negative words and positive words. Relative to positive words (e.g., kitten), negative words (e.g., spider) elicited slower lexical decisions but faster valence judgments. Results therefore indicate that negative stimuli do not cause a generalized motor suppression. Rather, negative stimuli elicit selective responding, with faster responses on tasks for which stimulus valence is response-relevant.
Effects of fine sediment, hyporheic flow, and spawning site characteristics on survival and development of bull trout embryos

USGS Publications Warehouse

Bowerman, Tracy; Neilson, Bethany; Budy, Phaedra

2014-01-01

Successful spawning is imperative for the persistence of salmonid populations, but relatively little research has been conducted to evaluate factors affecting early life-stage survival for bull trout (Salvelinus confluentus), a threatened char. We conducted a field experiment to assess the relationship between site-specific environmental factors and bull trout embryo survival and fry emergence timing. Survival from egg to hatch was negatively related to percent fine sediment (<1 mm) in the redd and positively related to the strength of downwelling at spawning sites. Survival of eggs to fry emergence was also negatively related to fine sediment, and the best statistical models included additional variables that described the rate of downwelling and intragravel flow within the incubation environment. Fry emerged at an earlier stage in development from redds with high percentages of fine sediment. Increased hydraulic conductivity via redd construction and selection of spawning sites with strong downwelling appear to enhance hyporheic flow rates and bull trout egg survival, but early life-stage success may ultimately be limited by intrusion of fine sediment into the incubation environment.
Visual search in complex displays: factors affecting conflict detection by air traffic controllers.

PubMed

Remington, R W; Johnston, J C; Ruthruff, E; Gold, M; Romera, M

2000-01-01

Recent free flight proposals to relax airspace constraints and give greater autonomy to aircraft have raised concerns about their impact on controller performance. Relaxing route and altitude restrictions would reduce the regularity of traffic through individual sectors, possibly impairing controller situation awareness. We examined the impact of this reduced regularity in four visual search experiments that tested controllers' detection of traffic conflicts in the four conditions created by factorial manipulation of fixed routes (present vs. absent) and altitude restrictions (present vs. absent). These four conditions were tested under varying levels of traffic load and conflict geometry (conflict time and conflict angle). Traffic load and conflict geometry showed strong and consistent effects in all experiments. Color coding altitude also substantially improved detection times. In contrast, removing altitude restrictions had only a small negative impact, and removing route restrictions had virtually no negative impact. In some cases conflict detection was actually better without fixed routes. The implications and limitations of these results for the feasibility of free flight are discussed. Actual or potential applications include providing guidance in the selection of free flight operational concepts.
Why are reproductively parasitic fish males so small?—influence of tactic-specific selection

NASA Astrophysics Data System (ADS)

Ota, Kazutaka; Kohda, Masanori; Sato, Tetsu

2010-12-01

Despite the wide prevalence of alternative reproductive tactics, little attention has been paid to why reproductively parasitic males are so small. In this study, we tackled this issue in a shell-brooding fish Lamprologus callipterus. Sneaky `dwarf males' of this fish remain much smaller than bourgeois conspecifics throughout their life and employ a unique parasitic tactic, i.e. entering into a gastropod shell where a female is spawning, passing through the space between the female and shell wall and staying behind her to ejaculate throughout the spawning event. Here, we tested the prediction that they remain small to get past her through the shell spaces by interpopulation comparison. We showed, across populations, a negative allometry for sexual size dimorphism, an exponential increase of female size with an increase in shell size and a negative correlation between the magnitude of sexual size dimorphism and shell size. These results suggest that the inner spaces strongly regulate dwarf male size. We conclude that the small bodies of dwarf males arise from adaptation to their unique reproductive behaviour.
A nursing career in mental health care: choices and motives of nursing students.

PubMed

Hoekstra, Hanneke J; van Meijel, Berno B; van der Hooft-Leemans, Truus G

2010-01-01

This article describes the results of a study into how first-year nursing students' perceptions of psychiatric patients and mental health care influence their choice of specialization in mental health care and future working in this sector. A descriptive qualitative study design with semi-structured interviews. Respondents were selected through purposive sampling among all first-year bachelor students attending a Dutch school of nursing. First-year nursing students have stereotype, mostly negative perceptions of psychiatric patients and mental health care. These perceptions strongly influence their future professional choices. The respondents provided various reasons for their decision not to major in mental health care, one of these being that the school did too little to counsel and inform them about mental health issues and a career in mental health care. As a result, their unrealistic perceptions prevailed. If schools offering bachelor of nursing programmes do not sufficiently counsel and inform students about mental health care, students will leave school with their stereotype, negative perception of mental health care intact. Mental health care institutions will run a great risk of losing potentially good nurses.
Tainted resurrection: metal pollution is linked with reduced hatching and high juvenile mortality in Daphnia egg banks.

PubMed

Rogalski, Mary A

2015-05-01

Many taxa, from plants to zooplankton, produce long-lasting dormant propagules capable of temporal dispersal. In some cases, propagules can persist for decades or even centuries before emerging from seed and egg banks. Despite impressive longevity, relatively little is known about how the chemical environment experienced before or during dormancy affects the fate and performance of individuals. This study examines the hatching rate and developmental success of Daphnia hatched from diapausing eggs isolated from sediments from four lakes that experienced varying levels of metal contamination. Two hundred seventy-three animals were hatched from lake sediments deposited over the past century. Hatching rate was negatively influenced by metal contamination and sediment age. There was a robust positive relationship between sediment metal concentrations and juvenile mortality in Daphnia hatching from those sediments. The negative effect of metals on Daphnia hatching and juvenile survival may stem from metal bioaccumulation, genetic effects, or reduced maternal investment in diapausing embryos. Regardless of the specific mechanism driving this trend, exposure to metals may impose strong selection on Daphnia diapausing egg banks.
Portrayal of negative qualities in a doctor as a potential teaching tool in medical ethics and humanism: Journey to the End of Night by Louis‐Ferdinand Céline

PubMed Central

Wolf, G

2006-01-01

Fictional stories about physicians and patients are increasingly used as a powerful teaching resource for medical students. Very often, but not exclusively, stories of physicians as positive role models are selected to teach students virtues and ethical values. Negative role models are rarely used and if so, physicians are rather described as medical quacks in such fiction then exhibiting primarily a corrupted character. I suggest that a fictional story that presents exclusively a negative role model of a physician could also be a valuable, admittedly difficult, teaching resource to demonstrate the consequences of absolute loss of ethical standards and virtues in physicians. A not widely known example of this genre is Louis‐Ferdinand Céline's (1894–1961) novel Voyage au bout de la nuit (Journey to the End of the Night), published in 1932. Having a strong autobiographical background, the novel described the adventures of the medicine student, Ferdinand Bardamu, during the first world war, in the African colonies as a trader, in the United States of America as factory worker, and later after finishing his education, as a doctor for the poor. Unfortunately, Dr Bardamu develops an unprofessional, even criminal behaviour, and may serve as a negative role model for the virtues of physicians. This article will familiarise the reader with the novel and its physician author. PMID:16461481
The strengths of r- and K-selection shape diversity-disturbance relationships.

PubMed

Bohn, Kristin; Pavlick, Ryan; Reu, Björn; Kleidon, Axel

2014-01-01

Disturbance is a key factor shaping species abundance and diversity in plant communities. Here, we use a mechanistic model of vegetation diversity to show that different strengths of r- and K-selection result in different disturbance-diversity relationships. R- and K-selection constrain the range of viable species through the colonization-competition tradeoff, with strong r-selection favoring colonizers and strong K-selection favoring competitors, but the level of disturbance also affects the success of species. This interplay among r- and K-selection and disturbance results in different shapes of disturbance-diversity relationships, with little variation of diversity with no r- and no K-selection, a decrease in diversity with r-selection with disturbance rate, an increase in diversity with K-selection, and a peak at intermediate values with strong r- and K-selection. We conclude that different disturbance-diversity relationships found in observations may reflect different intensities of r- and K-selection within communities, which should be inferable from broader observations of community composition and their ecophysiological trait ranges.
PPARγ partial agonist GQ-16 strongly represses a subset of genes in 3T3-L1 adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milton, Flora Aparecida; Genomic Medicine, Houston Methodist Research Institute, Houston, TX; Cvoro, Aleksandra

Thiazolidinediones (TZDs) are peroxisome proliferator-activated receptor gamma (PPARγ) agonists that improve insulin resistance but trigger side effects such as weight gain, edema, congestive heart failure and bone loss. GQ-16 is a PPARγ partial agonist that improves glucose tolerance and insulin sensitivity in mouse models of obesity and diabetes without inducing weight gain or edema. It is not clear whether GQ-16 acts as a partial agonist at all PPARγ target genes, or whether it displays gene-selective actions. To determine how GQ-16 influences PPARγ activity on a gene by gene basis, we compared effects of rosiglitazone (Rosi) and GQ-16 in mature 3T3-L1more » adipocytes using microarray and qRT-PCR. Rosi changed expression of 1156 genes in 3T3-L1, but GQ-16 only changed 89 genes. GQ-16 generally showed weak effects upon Rosi induced genes, consistent with partial agonist actions, but a subset of modestly Rosi induced and strongly repressed genes displayed disproportionately strong GQ-16 responses. PPARγ partial agonists MLR24 and SR1664 also exhibit disproportionately strong effects on transcriptional repression. We conclude that GQ-16 displays a continuum of weak partial agonist effects but efficiently represses some negatively regulated PPARγ responsive genes. Strong repressive effects could contribute to physiologic actions of GQ-16. - Highlights: • GQ-16 is an insulin sensitizing PPARγ ligand with reduced harmful side effects. • GQ-16 displays a continuum of weak partial agonist activities at PPARγ-induced genes. • GQ-16 exerts strong repressive effects at a subset of genes. • These inhibitor actions should be evaluated in models of adipose tissue inflammation.« less
High brilliance negative ion and neutral beam source

DOEpatents

Compton, Robert N.

1991-01-01

A high brilliance mass selected (Z-selected) negative ion and neutral beam source having good energy resolution. The source is based upon laser resonance ionization of atoms or molecules in a small gaseous medium followed by charge exchange through an alkali oven. The source is capable of producing microampere beams of an extremely wide variety of negative ions, and milliampere beams when operated in the pulsed mode.
Characteristics of ionospheric storms in East Asia

NASA Astrophysics Data System (ADS)

Wang, Xiao; Wang, Guojun; Shi, Jiankui

The ionosphere experiences intense response during the geomagnetic storm and it varies with latitude and longitude. The DPS-4 digisonde measurements and GPS-TEC data of ionospheric stations located at different latitudes in the longitudinal sector of 90-130E during 2002 to 2012 were analyzed to investigate the ionospheric effects in the different latitude of East Asia during geomagnetic storm. About 70 geomagnetic storms are selected according to the Dst index and observed data and they are in different seasons and different solar activity levels. A few quiet days’ averages of data before geomagnetic storm were used as the undisturbed level. Results show that for the middle and high latitude, the short-lived positive disturbance associated with the initial phase of the every storm was observed in each season and then the disturbances were negative till the termination of storm. At the low latitude, storm-time disturbances of foF2 have obvious diurnal, seasonal and solar cycle characteristics. Generally, geomagnetic activity will cause foF2 to increase at daytime and decrease at nighttime except for the summer in low solar activity period. The intensity of response of foF2 is stronger at nighttime than that at daytime. The negative ionospheric storm effect is the strongest in summer and the positive ionospheric storm effect is the strongest in winter. In high solar activity period, the diurnal variation of the response of foF2 is very pronounced in each season, and the strong ionospheric response can last several days. In low solar activity period, ionospheric response has very pronounced diurnal variation in winter only. It’s notable that geomagnetic activities occurred at local time nighttime can cause stronger and longer responses of foF2 at the low latitude. All in all, the obvious negative phase ionospheric storms often occurred at the low latitude. Moreover a notable phenomenon was observed for the low latitude, there are the intensive oscillations of foF2 occurring during the main storm phase of enhanced storm in Hainan, and it occurred in the morning generally. For the TEC data, strong disturbances can be observed simultaneously from high latitude to low latitude during the main phase of some storms. Generally strong/weak storms can cause the negative/positive phase storms of TEC in the low latitude and which are obvious in the daytime for the summer and winter and in the period from noon to midnight for the equinox. The differences of the responses of foF2 and TEC are also investigated.
Update on Multiple Ovulations in Dairy Cattle

PubMed Central

Macmillan, Kira; Kastelic, John P.

2018-01-01

Simple Summary Multiple ovulations (MOV) in cattle can lead to twin pregnancies, which negatively affects the health, production, and reproduction of cows. Despite many studies, the causal mechanisms behind MOV are still not well understood. There is a general agreement that MOV are more likely during periods of low progesterone (P4), which may increase the luteinizing hormone (LH) release at the time of selection, resulting in more than one follicle becoming dominant. The MOV rate also increases in older cows and when the selection of a dominant follicle occurs concurrently with a high milk yield. Additional risk factors for MOV are ovarian cysts, diet, season, and genetics. A better understanding of the mechanisms underlying MOV may help to mitigate twinning, perhaps through the appropriate reproductive management protocols or genetic selection. Abstract This review updates the causal mechanisms and risk factors for multiple ovulations (MOV) in cattle. Clearly, MOV can lead to twin pregnancies, which negatively affects the health, production, and reproduction of cows. Therefore, a better understanding of the factors causing MOV may help to reduce twinning. Multiple ovulations occur after two or more follicles deviate and achieve codominance. The MOV rate is influenced by a complex network of hormones. For example, MOV is more common during periods of low progesterone (P4), that is, in anovulatory cattle or when luteolysis coincides with the selection of the future ovulatory follicle. There is also strong evidence for the luteinizing hormone (LH) being the primary factor leading to codominance, as high P4 concentrations suppress the transient LH surges and can reduce the ovulation rate in cattle or even inhibit deviation. Rates of MOV are increased in older and higher-producing dairy cows. Increased milk production and dry matter intake (DMI) increases hormone clearance, including P4; however, the association between milk yield and MOV has not been consistent. Additional risk factors for MOV include ovarian cysts, diet, season, and genetics. PMID:29695075

Why humans might help strangers

PubMed Central

Raihani, Nichola J.; Bshary, Redouan

2015-01-01

Humans regularly help strangers, even when interactions are apparently unobserved and unlikely to be repeated. Such situations have been simulated in the laboratory using anonymous one-shot games (e.g., prisoner’s dilemma) where the payoff matrices used make helping biologically altruistic. As in real-life, participants often cooperate in the lab in these one-shot games with non-relatives, despite that fact that helping is under negative selection under these circumstances. Two broad explanations for such behavior prevail. The “big mistake” or “mismatch” theorists argue that behavior is constrained by psychological mechanisms that evolved predominantly in the context of repeated interactions with known individuals. In contrast, the cultural group selection theorists posit that humans have been selected to cooperate in anonymous one-shot interactions due to strong between-group competition, which creates interdependence among in-group members. We present these two hypotheses before discussing alternative routes by which humans could increase their direct fitness by cooperating with strangers under natural conditions. In doing so, we explain why the standard lab games do not capture real-life in various important aspects. First, asymmetries in the cost of perceptual errors regarding the context of the interaction (one-shot vs. repeated; anonymous vs. public) might have selected for strategies that minimize the chance of making costly behavioral errors. Second, helping strangers might be a successful strategy for identifying other cooperative individuals in the population, where partner choice can turn strangers into interaction partners. Third, in contrast to the assumptions of the prisoner’s dilemma model, it is possible that benefits of cooperation follow a non-linear function of investment. Non-linear benefits result in negative frequency dependence even in one-shot games. Finally, in many real-world situations individuals are able to parcel investments such that a one-shot interaction is turned into a repeated game of many decisions. PMID:25750619
Apolipoprotein L1 confers pH-switchable ion permeability to phospholipid vesicles.

PubMed

Bruno, Jonathan; Pozzi, Nicola; Oliva, Jonathan; Edwards, John C

2017-11-03

Apolipoprotein L1 (ApoL1) is a human serum protein conferring resistance to African trypanosomes, and certain ApoL1 variants increase susceptibility to some progressive kidney diseases. ApoL1 has been hypothesized to function like a pore-forming colicin and has been reported to have permeability effects on both intracellular and plasma membranes. Here, to gain insight into how ApoL1 may function in vivo , we used vesicle-based ion permeability, direct membrane association, and intrinsic fluorescence to study the activities of purified recombinant ApoL1. We found that ApoL1 confers chloride-selective permeability to preformed phospholipid vesicles and that this selectivity is strongly pH-sensitive, with maximal activity at pH 5 and little activity above pH 7. When ApoL1 and lipid were allowed to interact at low pH and were then brought to neutral pH, chloride permeability was suppressed, and potassium permeability was activated. Both chloride and potassium permeability linearly correlated with the mass of ApoL1 in the reaction mixture, and both exhibited lipid selectivity, requiring the presence of negatively charged lipids for activity. Potassium, but not chloride, permease activity required the presence of calcium ions in both the association and activation steps. Direct assessment of ApoL1-lipid associations confirmed that ApoL1 stably associates with phospholipid vesicles, requiring low pH and the presence of negatively charged phospholipids for maximal binding. Intrinsic fluorescence of ApoL1 supported the presence of a significant structural transition when ApoL1 is mixed with lipids at low pH. This pH-switchable ion-selective permeability may explain the different effects of ApoL1 reported in intracellular and plasma membrane environments. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
Impact of media and antifoam selection on monoclonal antibody production and quality using a high throughput micro‐bioreactor system

PubMed Central

Velugula‐Yellela, Sai Rashmika; Williams, Abasha; Trunfio, Nicholas; Hsu, Chih‐Jung; Chavez, Brittany; Yoon, Seongkyu

2017-01-01

Monoclonal antibody production in commercial scale cell culture bioprocessing requires a thorough understanding of the engineering process and components used throughout manufacturing. It is important to identify high impact components early on during the lifecycle of a biotechnology‐derived product. While cell culture media selection is of obvious importance to the health and productivity of mammalian bioreactor operations, other components such as antifoam selection can also play an important role in bioreactor cell culture. Silicone polymer‐based antifoams were known to have negative impacts on cell health, production, and downstream filtration and purification operations. High throughput screening in micro‐scale bioreactors provides an efficient strategy to identify initial operating parameters. Here, we utilized a micro‐scale parallel bioreactor system to study an IgG1 producing CHO cell line, to screen Dynamis, ProCHO5, PowerCHO2, EX‐Cell Advanced, and OptiCHO media, and 204, C, EX‐Cell, SE‐15, and Y‐30 antifoams and their impacts on IgG1 production, cell growth, aggregation, and process control. This study found ProCHO5, EX‐Cell Advanced, and PowerCHO2 media supported strong cellular growth profiles, with an IVCD of 25‐35 × 106 cells‐d/mL, while maintaining specific antibody production (Qp > 2 pg/cell‐d) for our model cell line and a monomer percentage above 94%. Antifoams C, EX‐Cell, and SE‐15 were capable of providing adequate control of foaming while antifoam 204 and Y‐30 noticeably stunted cellular growth. This work highlights the utility of high throughput micro bioreactors and the importance of identifying both positive and negative impacts of media and antifoam selection on a model IgG1 producing CHO cell line. © 2017 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 34:262–270, 2018 PMID:29086492
Influence of Strong versus Weak Fair Employment Policies and Applicant's Sex on Selection Decisions and Salary Recommendations in a Management Simulation.

ERIC Educational Resources Information Center

Rosen, Benson; Mericle, Mary F.

1979-01-01

Strong and weak policies on fair employment were equally effective in counteracting sex bias in selection decisions; however, lower starting salaries were recommended for females compared to males in the strong fair employment policy condition. (Author/IRT)
Pathogen prevalence predicts human cross-cultural variability in individualism/collectivism.

PubMed

Fincher, Corey L; Thornhill, Randy; Murray, Damian R; Schaller, Mark

2008-06-07

Pathogenic diseases impose selection pressures on the social behaviour of host populations. In humans (Homo sapiens), many psychological phenomena appear to serve an antipathogen defence function. One broad implication is the existence of cross-cultural differences in human cognition and behaviour contingent upon the relative presence of pathogens in the local ecology. We focus specifically on one fundamental cultural variable: differences in individualistic versus collectivist values. We suggest that specific behavioural manifestations of collectivism (e.g. ethnocentrism, conformity) can inhibit the transmission of pathogens; and so we hypothesize that collectivism (compared with individualism) will more often characterize cultures in regions that have historically had higher prevalence of pathogens. Drawing on epidemiological data and the findings of worldwide cross-national surveys of individualism/collectivism, our results support this hypothesis: the regional prevalence of pathogens has a strong positive correlation with cultural indicators of collectivism and a strong negative correlation with individualism. The correlations remain significant even when controlling for potential confounding variables. These results help to explain the origin of a paradigmatic cross-cultural difference, and reveal previously undocumented consequences of pathogenic diseases on the variable nature of human societies.
Factors affecting the use of contraception in Bangladesh: a multivariate analysis.

PubMed

Ullah, M S; Chakraborty, N

1993-09-01

The government of Bangladesh since independence has tried to strengthen the national family planning program. Using data from the 1989 Bangladesh Fertility Survey on a nationally representative sample of 7984 rural and urban households, the authors consider fifteen socioeconomic and demographic variables and assess their relative importance in relation to current contraceptive use. The data indicate that 31.1% of younger and lower parity women use contraceptives. Women's education, followed by women's participation in family planning decision making, were the most important of selected factors which positively affect current use of contraception. Administrative division, desire for additional children, urban residence, and family planning worker visits were also important factors significantly and positively related to the current use of contraception. Husband's occupation was strongly associated with contraceptive use. Child loss, however, was negatively associated with contraceptive use, followed by sex composition of living children. The authors suggest that women should be encouraged to participate in family decisions, and become informed about their rights, privileges, and family law. Finally, it was found that education makes less difference to contraceptive use where family planning programs are strong.
Prognostic and predictive value of tumor-infiltrating lymphocytes in two phase III randomized adjuvant breast cancer trials

PubMed Central

Dieci, M. V.; Mathieu, M. C.; Guarneri, V.; Conte, P.; Delaloge, S.; Andre, F.; Goubar, A.

2015-01-01

Background Tumor-infiltrating lymphocytes (TILs) are emerging as strong prognostic factor for early breast cancer patients, especially in the triple-negative subtype. Here, we aim to validate previous findings on the prognostic role of TIL in the context of two randomized adjuvant trials and to investigate whether lymphocyte infiltrates can predict benefit from adjuvant anthracyclines. Patients and methods A total of 816 patients enrolled and treated at the Gustave Roussy in the context of two multicentric randomized trials comparing adjuvant anthracyclines versus no chemotherapy were included in the present analysis. Primary end point was overall survival (OS). Hematoxilin and eosin slides of primary tumors were retrieved and evaluated for the percentage of intratumoral (It) and stromal (Str) TIL. Each case was also defined as high-TIL or low-TIL breast cancer adopting previously validated cutoffs. Results TIL were assessable for 781 of 816 cases. High-TIL cases were more likely grade 3 and estrogen receptor (ER)-negative (P < 0.001). In multivariate analysis, both continuous It-TIL and Str-TIL were strong prognostic factors for OS [hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.77–0.95 P = 0.003; HR 0.89, 95% CI 0.81–0.96, P = 0.005 for It-TIL and Str-TIL, respectively]. The prognostic effect of continuous TIL was limited to triple-negative and HER2-positive patients. Ten-year OS rates were: 89% and 68% for triple-negative high-TIL and low-TIL, respectively (HR 0.44, 95% CI 0.18–1.10, P = 0.07) and 78% and 57% for HER2-positive high-TIL versus low-TIL, respectively (HR 0.46, 95% CI 0.20–1.11, P = 0.08). Either continuous or binary TIL variables did not predict for the efficacy of anthracyclines. Test for interaction P value was not significant in the whole study population and in subgroups (ER+/HER2−, HER2+, ER−/HER2−). Conclusions We confirmed the prognostic role of TIL in triple-negative early breast cancer and suggested a prognostic impact in HER2+ patients as well. Basing on our data, TIL should not be used as a parameter to select patients for anthracyclines chemotherapy. PMID:25995301
Positive Selection during the Evolution of the Blood Coagulation Factors in the Context of Their Disease-Causing Mutations

PubMed Central

Rallapalli, Pavithra M.; Orengo, Christine A.; Studer, Romain A.; Perkins, Stephen J.

2014-01-01

Blood coagulation occurs through a cascade of enzymes and cofactors that produces a fibrin clot, while otherwise maintaining hemostasis. The 11 human coagulation factors (FG, FII–FXIII) have been identified across all vertebrates, suggesting that they emerged with the first vertebrates around 500 Ma. Human FVIII, FIX, and FXI are associated with thousands of disease-causing mutations. Here, we evaluated the strength of selective pressures on the 14 genes coding for the 11 factors during vertebrate evolution, and compared these with human mutations in FVIII, FIX, and FXI. Positive selection was identified for fibrinogen (FG), FIII, FVIII, FIX, and FX in the mammalian Primates and Laurasiatheria and the Sauropsida (reptiles and birds). This showed that the coagulation system in vertebrates was under strong selective pressures, perhaps to adapt against blood-invading pathogens. The comparison of these results with disease-causing mutations reported in FVIII, FIX, and FXI showed that the number of disease-causing mutations, and the probability of positive selection were inversely related to each other. It was concluded that when a site was under positive selection, it was less likely to be associated with disease-causing mutations. In contrast, sites under negative selection were more likely to be associated with disease-causing mutations and be destabilizing. A residue-by-residue comparison of the FVIII, FIX, and FXI sequence alignments confirmed this. This improved understanding of evolutionary changes in FVIII, FIX, and FXI provided greater insight into disease-causing mutations, and better assessments of the codon sites that may be mutated in applications of gene therapy. PMID:25158795
Seamless Genome Editing in Rice via Gene Targeting and Precise Marker Elimination.

PubMed

Nishizawa-Yokoi, Ayako; Saika, Hiroaki; Toki, Seiichi

2016-01-01

Positive-negative selection using hygromycin phosphotransferase (hpt) and diphtheria toxin A-fragment (DT-A) as positive and negative selection markers, respectively, allows enrichment of cells harboring target genes modified via gene targeting (GT). We have developed a successful GT system employing positive-negative selection and subsequent precise marker excision via the piggyBac transposon derived from the cabbage looper moth to introduce desired modifications into target genes in the rice genome. This approach could be applied to the precision genome editing of almost all endogenous genes throughout the genome, at least in rice.
The genealogy of sequences containing multiple sites subject to strong selection in a subdivided population.

PubMed Central

Nordborg, Magnus; Innan, Hideki

2003-01-01

A stochastic model for the genealogy of a sample of recombining sequences containing one or more sites subject to selection in a subdivided population is described. Selection is incorporated by dividing the population into allelic classes and then conditioning on the past sizes of these classes. The past allele frequencies at the selected sites are thus treated as parameters rather than as random variables. The purpose of the model is not to investigate the dynamics of selection, but to investigate effects of linkage to the selected sites on the genealogy of the surrounding chromosomal region. This approach is useful for modeling strong selection, when it is natural to parameterize the past allele frequencies at the selected sites. Several models of strong balancing selection are used as examples, and the effects on the pattern of neutral polymorphism in the chromosomal region are discussed. We focus in particular on the statistical power to detect balancing selection when it is present. PMID:12663556
The genealogy of sequences containing multiple sites subject to strong selection in a subdivided population.

PubMed

Nordborg, Magnus; Innan, Hideki

2003-03-01

A stochastic model for the genealogy of a sample of recombining sequences containing one or more sites subject to selection in a subdivided population is described. Selection is incorporated by dividing the population into allelic classes and then conditioning on the past sizes of these classes. The past allele frequencies at the selected sites are thus treated as parameters rather than as random variables. The purpose of the model is not to investigate the dynamics of selection, but to investigate effects of linkage to the selected sites on the genealogy of the surrounding chromosomal region. This approach is useful for modeling strong selection, when it is natural to parameterize the past allele frequencies at the selected sites. Several models of strong balancing selection are used as examples, and the effects on the pattern of neutral polymorphism in the chromosomal region are discussed. We focus in particular on the statistical power to detect balancing selection when it is present.
Social and Emotional Learning in the Classroom: Evaluation of "Strong Kids" and "Strong Teens" on Students' Social-Emotional Knowledge and Symptoms

ERIC Educational Resources Information Center

Merrell, Kenneth W.; Juskelis, Michael P.; Tran, Oanh K.; Buchanan, Rohanna

2008-01-01

This article describes the results of three pilot studies that were conducted to evaluate the recently developed "Strong Kids" and "Strong Teens" social-emotional learning programs in increasing students' knowledge of healthy social-emotional behavior and decreasing their symptoms of negative affect and emotional distress. The first study included…
Reduced TCR signaling potential impairs negative selection but does not result in autoimmune disease

PubMed Central

Hwang, SuJin; Song, Ki-Duk; Lesourne, Renaud; Lee, Jan; Pinkhasov, Julia; Li, LiQi; El-Khoury, Dalal

2012-01-01

Negative selection and regulatory T (T reg) cell development are two thymus-dependent processes necessary for the enforcement of self-tolerance, and both require high-affinity interactions between the T cell receptor (TCR) and self-ligands. However, it remains unclear if they are similarly impacted by alterations in TCR signaling potential. We generated a knock-in allele (6F) of the TCR ζ chain gene encoding a mutant protein lacking signaling capability whose expression is controlled by endogenous ζ regulatory sequences. Although negative selection was defective in 6F/6F mice, leading to the survival of autoreactive T cells, 6F/6F mice did not develop autoimmune disease. We found that 6F/6F mice generated increased numbers of thymus-derived T reg cells. We show that attenuation of TCR signaling potential selectively impacts downstream signaling responses and that this differential effect favors Foxp3 expression and T reg cell lineage commitment. These results identify a potential compensatory pathway for the enforcement of immune tolerance in response to defective negative selection caused by reduced TCR signaling capability. PMID:22945921
Protein Kinase Cδ Promotes Transitional B Cell-Negative Selection and Limits Proximal B Cell Receptor Signaling To Enforce Tolerance

PubMed Central

Zikherman, Julie; Lau, Tannia; Leitges, Michael; Weiss, Arthur

2014-01-01

Protein kinase Cδ (PKCδ) deficiency causes autoimmune pathology in humans and mice and is crucial for the maintenance of B cell homeostasis. However, the mechanisms underlying autoimmune disease in PKCδ deficiency remain poorly defined. Here, we address the antigen-dependent and -independent roles of PKCδ in B cell development, repertoire selection, and antigen responsiveness. We demonstrate that PKCδ is rapidly phosphorylated downstream of both the B cell receptor (BCR) and the B cell-activating factor (BAFF) receptor. We found that PKCδ is essential for antigen-dependent negative selection of splenic transitional B cells and is required for activation of the proapoptotic Ca2+-Erk pathway that is selectively activated during B cell-negative selection. Unexpectedly, we also identified a previously unrecognized role for PKCδ as a proximal negative regulator of BCR signaling that substantially impacts survival and proliferation of mature follicular B cells. As a consequence of these distinct roles, PKCδ deficiency leads to the survival and development of a B cell repertoire that is not only aberrantly autoreactive but also hyperresponsive to antigen stimulation. PMID:24515435
Thermodynamic Basis of Selectivity in the Interactions of Tissue Inhibitors of Metalloproteinases N-domains with Matrix Metalloproteinases-1, -3, and -14.

PubMed

Zou, Haiyin; Wu, Ying; Brew, Keith

2016-05-20

The four tissue inhibitors of metalloproteinases (TIMPs) are potent inhibitors of the many matrixins (MMPs), except that TIMP1 weakly inhibits some MMPs, including MMP14. The broad-spectrum inhibition of MMPs by TIMPs and their N-domains (NTIMPs) is consistent with the previous isothermal titration calorimetric finding that their interactions are entropy-driven but differ in contributions from solvent and conformational entropy (ΔSsolv, ΔSconf), estimated using heat capacity changes (ΔCp). Selective engineered NTIMPs have potential applications for treating MMP-related diseases, including cancer and cardiomyopathy. Here we report isothermal titration calorimetric studies of the effects of selectivity-modifying mutations in NTIMP1 and NTIMP2 on the thermodynamics of their interactions with MMP1, MMP3, and MMP14. The weak inhibition of MMP14 by NTIMP1 reflects a large conformational entropy penalty for binding. The T98L mutation, peripheral to the NTIMP1 reactive site, enhances binding by increasing ΔSsolv but also reduces ΔSconf However, the same mutation increases NTIMP1 binding to MMP3 in an interaction that has an unusual positive ΔCp This indicates a decrease in solvent entropy compensated by increased conformational entropy, possibly reflecting interactions involving alternative conformers. The NTIMP2 mutant, S2D/S4A is a selective MMP1 inhibitor through electrostatic effects of a unique MMP-1 arginine. Asp-2 increases reactive site polarity, reducing ΔCp, but increases conformational entropy to maintain strong binding to MMP1. There is a strong negative correlation between ΔSsolv and ΔSconf for all characterized interactions, but the data for each MMP have characteristic ranges, reflecting intrinsic differences in the structures and dynamics of their free and inhibitor-bound forms. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.
When Negation and Epistemic Modality Combine: The Role of Information Strength in Child Language

ERIC Educational Resources Information Center

Moscati, Vincenzo; Crain, Stephen

2014-01-01

Negative sentences with epistemic modals (e.g., John "might" not come/John "can" not come) contain two logical operators, negation and the modal, which yields a potential semantic ambiguity depending on scope assignment. The two possible readings are in a subset/superset relation, such that the strong reading ("can…
Two-Way Selection for Growth Rate in the Common Carp (CYPRINUS CARPIO L.)

PubMed Central

Moav, R.; Wohlfarth, G.

1976-01-01

The domesticated European carp was subjected to a two-way selection for growth rate. Five generations of mass selection for faster growth rate did not yield any response, but subsequent selection between groups (families) resulted in considerable progress while maintaining a large genetic variance. Selection for slow growth rate yielded relatively strong response for the first three generations. Random-bred control lines suffered from strong inbreeding depression and when two lines were crossed, the F1 showed a high degree of heterosis. Selection was performed on pond-raised fish, but growth rate was also tested in cages. A strong pond-cage genetic interaction was found. A theoretical explanation was suggested involving overdominance for fast growth rate and amplification through competition of intra-group but not inter-group variation. PMID:1248737
Factors associated with cardiac mortality in developed countries with particular reference to the consumption of wine.

PubMed

St Leger, A S; Cochrane, A L; Moore, F

1979-05-12

Deaths from ischaemic heart-disease in 18 developed countries are not strongly associated with health-service factors such as doctor and nurse density. There is a negative association with gross national product per capita and a positive but inconsistent association with saturated and monounsaturated fat intake. The principal finding is a strong and specific negative association between ischaemic heart-disease deaths and alcohol consumption. This is shown to be wholly attributable to wine consumption.
Negative correlation between nuptial throat colour and blood parasite load in male European green lizards supports the Hamilton-Zuk hypothesis

NASA Astrophysics Data System (ADS)

Molnár, Orsolya; Bajer, Katalin; Mészáros, Boglárka; Török, János; Herczeg, Gábor

2013-06-01

During female mate choice, conspicuous male sexual signals are used to infer male quality and choose the best sire for the offspring. The theory of parasite-mediated sexual selection (Hamilton-Zuk hypothesis) presumes that parasite infection can influence the elaboration of sexual signals: resistant individuals can invest more energy into signal expression and thus advertise their individual quality through signal intensity. By preferring these males, females can provide resistance genes for their offspring. Previous research showed that nuptial throat colour of male European green lizard, Lacerta viridis, plays a role in both inter- and intrasexual selections as a condition-dependent multiple signalling system. The aim of this study was to test the predictions of the Hamilton-Zuk hypothesis on male European green lizards. By blood sampling 30 adult males during the reproductive season, we found members of the Haemogregarinidae family in all but one individual (prevalence = 96 %). The infection intensity showed strong negative correlation with the throat and belly colour brightness in line with the predictions of the Hamilton-Zuk hypothesis. In addition, we found other correlations between infection intensity and other fitness-related traits, suggesting that parasite load has a remarkable effect on individual fitness. This study shows that throat patch colour of the European green lizards not only is a multiple signalling system but also possibly acts as an honest sexual signal of health state in accordance with the Hamilton-Zuk hypothesis.
Modeling the effect of toe clipping on treefrog survival: Beyond the return rate

USGS Publications Warehouse

Waddle, J.H.; Rice, K.G.; Mazzotti, F.J.; Percival, H.F.

2008-01-01

Some studies have described a negative effect of toe clipping on return rates of marked anurans, but the return rate is limited in that it does not account for heterogeneity of capture probabilities. We used open population mark-recapture models to estimate both apparent survival (ϕ) and the recapture probability (p) of two treefrog species individually marked by clipping 2–4 toes. We used information-theoretic model selection to examine the effect of toe clipping on survival while accounting for variation in capture probability. The model selection results indicate strong support for an effect of toe clipping on survival of Green Treefrogs (Hyla cinerea) and only limited support for an effect of toe clipping on capture probability. We estimate there was a mean absolute decrease in survival of 5.02% and 11.16% for Green Treefrogs with three and four toes removed, respectively, compared to individuals with just two toes removed. Results for Squirrel Treefrogs (Hyla squirella) indicate little support for an effect of toe clipping on survival but may indicate some support for a negative effect on capture probability. We believe that the return rate alone should not be used to examine survival of marked animals because constant capture probability must be assumed, and our examples demonstrate how capture probability may vary over time and among groups. Mark-recapture models provide a method for estimating the effect of toe clipping on anuran survival in situations where unique marks are applied.

Genotypic character relationship and phenotypic path coefficient analysis in chili pepper genotypes grown under tropical condition.

PubMed

Usman, Magaji G; Rafii, Mohd Y; Martini, Mohammad Y; Oladosu, Yusuff; Kashiani, Pedram

2017-03-01

Studies on genotypic and phenotypic correlations among characters of crop plants are useful in planning, evaluating and setting selection criteria for the desired characters in a breeding program. The present study aimed to estimate the phenotypic correlation coefficients among yield and yield attributed characters and to work out the direct and indirect effects of yield-related characters on yield per plant using path coefficient analysis. Twenty-six genotypes of chili pepper were laid out in a randomized complete block design with three replications. Yield per plant showed positive and highly significant (P ≤ 0.01) correlations with most of the characters studied at both the phenotypic and genotypic levels. By contrast, disease incidence and days to flowering showed a significant negative association with yield. Fruit weight and number of fruits exerted positive direct effect on yield and also had a positive and significant (P ≤ 0.01) correlation with yield per plant. However, fruit length showed a low negative direct effect with a strong and positive indirect effect through fruit weight on yield and had a positive and significant association with yield. Longer fruits, heavy fruits and a high number of fruits are variables that are related to higher yields of chili pepper under tropical conditions and hence could be used as a reliable indicator in indirect selection for yield. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.
Medical home characteristics and the pediatric patient experience.

PubMed

Burnet, Deborah; Gunter, Kathryn E; Nocon, Robert S; Gao, Yue; Jin, Janel; Fairchild, Paige; Chin, Marshall H

2014-11-01

The patient-centered medical home (PCMH) has roots in pediatrics, yet we know little about the experience of pediatric patients in PCMH settings. To examine the association between clinic PCMH characteristics and pediatric patient experience as reported by parents. We assessed the cross-sectional correlation between clinic PCMH characteristics and pediatric patient experience in 24 clinics randomly selected from the Safety Net Medical Home Initiative, a 5-state PCMH demonstration project. PCMH characteristics were measured with surveys of randomly selected providers and staff; surveys generated 0 (worst) to 100 (best) scores for 5 subscales, and a total score. Patient experience was measured through surveying parents of pediatric patients. Questions from the Consumer Assessment of Healthcare Providers and Systems-Clinician and Group instrument produced 4 patient experience measures: timeliness, physician communication, staff helpfulness, and overall rating. To investigate the relationship between PCMH characteristics and patient experience, we used generalized estimating equations with an exchangeable correlation structure. We included 440 parents and 214 providers and staff in the analysis. Total PCMH score was not associated with parents' assessment of patient experience; however, PCMH subscales were associated with patient experience in different directions. In particular, quality improvement activities undertaken by clinics were strongly associated with positive ratings of patient experience, whereas patient care management activities were associated with more negative reports of patient experience. Future work should bolster features of the PCMH that work well for patients while investigating which PCMH features negatively impact patient experience, to yield a better patient experience overall.
High Resolution Spectrometry of Leaf and Canopy Chemistry for Biochemical Cycling

NASA Technical Reports Server (NTRS)

Spanner, M. A.; Peterson, D. L.; Acevedo, W.; Matson, P.

1985-01-01

High-resolution laboratory spectrophotometer and Airborne Imaging Spectrometer (AIS) data were used to analyze forest leaf and canopy chemistry. Fundamental stretching frequencies of organic bonds in the visible, near infrared and short-wave infrared are indicative of concentrations and total content of nitrogen, phosphorous, starch and sugar. Laboratory spectrophotometer measurements showed very strong negative correlations with nitrogen (measured using wet chemistry) in the visible wavelengths. Strong correlations with green wet canopy weight in the atmospheric water absorption windows were observed in the AIS data. A fairly strong negative correlation between the AIS data at 1500 nm and total nitrogen and nitrogen concentration was evident. This relationship corresponds very closely to protein absorption features near 1500 nm.
Induction of phenolic metabolites and physiological changes in chamomile plants in relation to nitrogen nutrition.

PubMed

Kováčik, Jozef; Klejdus, Bořivoj

2014-01-01

Alternative tools, such as the manipulation of mineral nutrition, may affect secondary metabolite production and thus the nutritional value of food/medicinal plants. We studied the impact of nitrogen (N) nutrition (nitrate/NO3(-) or ammonium/NH4(+) nitrogen) and subsequent nitrogen deficit on phenolic metabolites and physiology in Matricaria chamomilla plants. NH4(+)-fed plants revealed a strong induction of selected phenolic metabolites but, at the same time, growth, Fv/Fm, tissue water content and soluble protein depletion occurred in comparison with NO3(-)-fed ones. On the other hand, NO3(-)-deficient plants also revealed an increase in phenolic metabolites but growth depression was not observed after the given exposure period. Free amino acids were more accumulated in NH4(+)-fed shoots (strong increase in arginine and proline mainly), while the pattern of roots' accumulation was independent of N form. Among phenolic acids, NH4(+) strongly elevated mainly the accumulation of chlorogenic acid. Within flavonoids, flavonols decreased while flavones strongly increased in response to N deficiency. Coumarin-related metabolites revealed a similar increase in herniarin glucosidic precursor in response to N deficiency, while herniarin was more accumulated in NO3(-)- and umbelliferone in NH4(+)-cultured plants. These data indicate a negative impact of NH4(+) as the only source of N on physiology, but also a higher stimulation of some valuable phenols. Nitrogen-induced changes in comparison with other food/crop plants are discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.
Negative-mass mitigation of Coulomb repulsion for terahertz undulator radiation of electron bunches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balal, N.; Magory, E.; Bandurkin, I. V.

2015-10-19

It is proposed to utilize the effect of negative mass for stabilization of the effective axial size of very dense and short electron bunches produced by photo-injector guns by using combined undulator and strong uniform magnetic fields. It has been shown that in the “abnormal” regime, an increase in the electron energy leads to a decrease in the axial velocity of the electron; due to the negative-mass effect, the Coulomb repulsion of electrons leads to their attraction and formation of a fairly stable and compact bunch “nucleus.” An undulator with a strong uniform magnetic field providing the negative-mass effect ismore » designed for an experimental source of terahertz radiation. The use of the negative-mass regime in this experiment should result in a long-pulse coherent spontaneous undulator emission from a short dense moderately relativistic (5.5 MeV) photo-injector electron bunch with a high (up to 20%) efficiency and a narrow frequency spectrum.« less
The effect of sexual selection on adaptation and extinction under increasing temperatures.

PubMed

Parrett, Jonathan M; Knell, Robert J

2018-04-25

Strong sexual selection has been reported to both enhance and hinder the adaptive capacity and persistence of populations when exposed to novel environments. Consequently, how sexual selection influences population adaption and persistence under stress remains widely debated. Here, we present two empirical investigations of the fitness consequences of sexual selection on populations of the Indian meal moth, Plodia interpunctella, exposed to stable or gradually increasing temperatures. When faced with increasing temperatures, strong sexual selection was associated with both increased fecundity and offspring survival compared with populations experiencing weak sexual selection, suggesting sexual selection acts to drive adaptive evolution by favouring beneficial alleles. Strong sexual selection did not, however, delay extinction when the temperature became excessively high. By manipulating individuals' mating opportunities during fitness assays, we were able to assess the effect of multiple mating independently from the effect of population-level sexual selection, and found that polyandry has a positive effect on both fecundity and offspring survival under increasing temperatures in those populations evolving with weak sexual selection. Within stable temperatures, there were some benefits from strong sexual selection but these were not consistent across the entire experiment, possibly reflecting changing costs and benefits of sexual selection under stabilizing and directional selection. These results indicate that sexual selection can provide a buffer against climate change and increase adaptation rates within a continuously changing environment. These positive effects of sexual selection may, however, be too small to protect populations and delay extinction when environmental changes are relatively rapid. © 2018 The Author(s).
Strong FGFR3 staining is a marker for FGFR3 fusions in diffuse gliomas

PubMed Central

Annala, Matti; Lehtinen, Birgitta; Kesseli, Juha; Haapasalo, Joonas; Ruusuvuori, Pekka; Yli-Harja, Olli; Visakorpi, Tapio; Haapasalo, Hannu; Nykter, Matti; Zhang, Wei

2017-01-01

Abstract Background Inhibitors of fibroblast growth factor receptors (FGFRs) have recently arisen as a promising treatment option for patients with FGFR alterations. Gene fusions involving FGFR3 and transforming acidic coiled-coil protein 3 (TACC3) have been detected in diffuse gliomas and other malignancies, and fusion-positive cases have responded well to FGFR inhibition. As high FGFR3 expression has been detected in fusion-positive tumors, we sought to determine the clinical significance of FGFR3 protein expression level as well as its potential for indicating FGFR3 fusions. Methods We performed FGFR3 immunohistochemistry on tissue microarrays containing 676 grades II–IV astrocytomas and 116 grades II–III oligodendroglial tumor specimens. Fifty-one cases were further analyzed using targeted sequencing. Results Moderate to strong FGFR3 staining was detected in gliomas of all grades, was more common in females, and was associated with poor survival in diffuse astrocytomas. Targeted sequencing identified FGFR3-TACC3 fusions and an FGFR3-CAMK2A fusion in 10 of 15 strongly stained cases, whereas no fusions were found in 36 negatively to moderately stained cases. Fusion-positive cases were predominantly female and negative for IDH and EGFR/PDGFRA/MET alterations. These and moderately stained cases show lower MIB-1 proliferation index than negatively to weakly stained cases. Furthermore, stronger FGFR3 expression was commonly observed in malignant tissue regions of lower cellularity in fusion-negative cases. Importantly, subregional negative FGFR3 staining was also observed in a few fusion-positive cases. Conclusions Strong FGFR3 protein expression is indicative of FGFR3 fusions and may serve as a clinically applicable predictive marker for treatment regimens based on FGFR inhibitors. PMID:28379477
Tradeoffs between hydraulic and mechanical stress responses of mature Norway spruce trunk wood.

PubMed

Rosner, Sabine; Klein, Andrea; Müller, Ulrich; Karlsson, Bo

2008-08-01

We tested the effects of growth characteristics and basic density on hydraulic and mechanical properties of mature Norway spruce (Picea abies (L.) Karst.) wood from six 24-year-old clones, grown on two sites in southern Sweden differing in water availability. Hydraulic parameters assessed were specific hydraulic conductivity at full saturation (ks100) and vulnerability to cavitation (Psi50), mechanical parameters included bending strength (sigma b), modulus of elasticity (MOE), compression strength (sigma a) and Young's modulus (E). Basic density, diameter at breast height, tree height, and hydraulic and mechanical parameters varied considerably among clones. Clonal means of hydraulic and mechanical properties were strongly related to basic density and to growth parameters across sites, especially to diameter at breast height. Compared with stem wood of slower growing clones, stem wood of rapidly growing clones had significantly lower basic density, lower sigma b, MOE, sigma a and E, was more vulnerable to cavitation, but had higher ks100. Basic density was negatively correlated to Psi50 and ks100. We therefore found a tradeoff between Psi50 and ks100. Clones with high basic density had significantly lower hydraulic vulnerability, but also lower hydraulic conductivity at full saturation and thus less rapid growth than clones with low basic density. This tradeoff involved a negative relationship between Psi50 and sigma b as well as MOE, and between ks100 and sigma b, MOE and sigma a. Basic density and Psi50 showed no site-specific differences, but tree height, diameter at breast height, ks100 and mechanical strength and stiffness were significantly lower at the drier site. Basic density had no influence on the site-dependent differences in hydraulic and mechanical properties, but was strongly negatively related to diameter at breast height. Selecting for growth may thus lead not only to a reduction in mechanical strength and stiffness but also to a reduction in hydraulic safety.
Facilitation and Competition among Invasive Plants: A Field Experiment with Alligatorweed and Water Hyacinth

PubMed Central

Wundrow, Emily J.; Carrillo, Juli; Gabler, Christopher A.; Horn, Katherine C.; Siemann, Evan

2012-01-01

Ecosystems that are heavily invaded by an exotic species often contain abundant populations of other invasive species. This may reflect shared responses to a common factor, but may also reflect positive interactions among these exotic species. Armand Bayou (Pasadena, TX) is one such ecosystem where multiple species of invasive aquatic plants are common. We used this system to investigate whether presence of one exotic species made subsequent invasions by other exotic species more likely, less likely, or if it had no effect. We performed an experiment in which we selectively removed exotic rooted and/or floating aquatic plant species and tracked subsequent colonization and growth of native and invasive species. This allowed us to quantify how presence or absence of one plant functional group influenced the likelihood of successful invasion by members of the other functional group. We found that presence of alligatorweed (rooted plant) decreased establishment of new water hyacinth (free-floating plant) patches but increased growth of hyacinth in established patches, with an overall net positive effect on success of water hyacinth. Water hyacinth presence had no effect on establishment of alligatorweed but decreased growth of existing alligatorweed patches, with an overall net negative effect on success of alligatorweed. Moreover, observational data showed positive correlations between hyacinth and alligatorweed with hyacinth, on average, more abundant. The negative effect of hyacinth on alligatorweed growth implies competition, not strong mutual facilitation (invasional meltdown), is occurring in this system. Removal of hyacinth may increase alligatorweed invasion through release from competition. However, removal of alligatorweed may have more complex effects on hyacinth patch dynamics because there were strong opposing effects on establishment versus growth. The mix of positive and negative interactions between floating and rooted aquatic plants may influence local population dynamics of each group and thus overall invasion pressure in this watershed. PMID:23119021
Facilitation and competition among invasive plants: a field experiment with alligatorweed and water hyacinth.

PubMed

Wundrow, Emily J; Carrillo, Juli; Gabler, Christopher A; Horn, Katherine C; Siemann, Evan

2012-01-01

Ecosystems that are heavily invaded by an exotic species often contain abundant populations of other invasive species. This may reflect shared responses to a common factor, but may also reflect positive interactions among these exotic species. Armand Bayou (Pasadena, TX) is one such ecosystem where multiple species of invasive aquatic plants are common. We used this system to investigate whether presence of one exotic species made subsequent invasions by other exotic species more likely, less likely, or if it had no effect. We performed an experiment in which we selectively removed exotic rooted and/or floating aquatic plant species and tracked subsequent colonization and growth of native and invasive species. This allowed us to quantify how presence or absence of one plant functional group influenced the likelihood of successful invasion by members of the other functional group. We found that presence of alligatorweed (rooted plant) decreased establishment of new water hyacinth (free-floating plant) patches but increased growth of hyacinth in established patches, with an overall net positive effect on success of water hyacinth. Water hyacinth presence had no effect on establishment of alligatorweed but decreased growth of existing alligatorweed patches, with an overall net negative effect on success of alligatorweed. Moreover, observational data showed positive correlations between hyacinth and alligatorweed with hyacinth, on average, more abundant. The negative effect of hyacinth on alligatorweed growth implies competition, not strong mutual facilitation (invasional meltdown), is occurring in this system. Removal of hyacinth may increase alligatorweed invasion through release from competition. However, removal of alligatorweed may have more complex effects on hyacinth patch dynamics because there were strong opposing effects on establishment versus growth. The mix of positive and negative interactions between floating and rooted aquatic plants may influence local population dynamics of each group and thus overall invasion pressure in this watershed.
Anti-HER2 IgY antibody-functionalized single-walled carbon nanotubes for detection and selective destruction of breast cancer cells

PubMed Central

2009-01-01

Background Nanocarrier-based antibody targeting is a promising modality in therapeutic and diagnostic oncology. Single-walled carbon nanotubes (SWNTs) exhibit two unique optical properties that can be exploited for these applications, strong Raman signal for cancer cell detection and near-infrared (NIR) absorbance for selective photothermal ablation of tumors. In the present study, we constructed a HER2 IgY-SWNT complex and demonstrated its dual functionality for both detection and selective destruction of cancer cells in an in vitro model consisting of HER2-expressing SK-BR-3 cells and HER2-negative MCF-7 cells. Methods The complex was constructed by covalently conjugating carboxylated SWNTs with anti-HER2 chicken IgY antibody, which is more specific and sensitive than mammalian IgGs. Raman signals were recorded on Raman spectrometers with a laser excitation at 785 nm. NIR irradiation was performed using a diode laser system, and cells with or without nanotube treatment were irradiated by 808 nm laser at 5 W/cm2 for 2 min. Cell viability was examined by the calcein AM/ethidium homodimer-1 (EthD-1) staining. Results Using a Raman optical microscope, we found the Raman signal collected at single-cell level from the complex-treated SK-BR-3 cells was significantly greater than that from various control cells. NIR irradiation selectively destroyed the complex-targeted breast cancer cells without harming receptor-free cells. The cell death was effectuated without the need of internalization of SWNTs by the cancer cells, a finding that has not been reported previously. Conclusion We have demonstrated that the HER2 IgY-SWNT complex specifically targeted HER2-expressing SK-BR-3 cells but not receptor-negative MCF-7 cells. The complex can be potentially used for both detection and selective photothermal ablation of receptor-positive breast cancer cells without the need of internalization by the cells. Thus, the unique intrinsic properties of SWNTs combined with high specificity and sensitivity of IgY antibodies can lead to new strategies for cancer detection and therapy. PMID:19799784
Anti-HER2 IgY antibody-functionalized single-walled carbon nanotubes for detection and selective destruction of breast cancer cells.

PubMed

Xiao, Yan; Gao, Xiugong; Taratula, Oleh; Treado, Stephen; Urbas, Aaron; Holbrook, R David; Cavicchi, Richard E; Avedisian, C Thomas; Mitra, Somenath; Savla, Ronak; Wagner, Paul D; Srivastava, Sudhir; He, Huixin

2009-10-02

Nanocarrier-based antibody targeting is a promising modality in therapeutic and diagnostic oncology. Single-walled carbon nanotubes (SWNTs) exhibit two unique optical properties that can be exploited for these applications, strong Raman signal for cancer cell detection and near-infrared (NIR) absorbance for selective photothermal ablation of tumors. In the present study, we constructed a HER2 IgY-SWNT complex and demonstrated its dual functionality for both detection and selective destruction of cancer cells in an in vitro model consisting of HER2-expressing SK-BR-3 cells and HER2-negative MCF-7 cells. The complex was constructed by covalently conjugating carboxylated SWNTs with anti-HER2 chicken IgY antibody, which is more specific and sensitive than mammalian IgGs. Raman signals were recorded on Raman spectrometers with a laser excitation at 785 nm. NIR irradiation was performed using a diode laser system, and cells with or without nanotube treatment were irradiated by 808 nm laser at 5 W/cm2 for 2 min. Cell viability was examined by the calcein AM/ethidium homodimer-1 (EthD-1) staining. Using a Raman optical microscope, we found the Raman signal collected at single-cell level from the complex-treated SK-BR-3 cells was significantly greater than that from various control cells. NIR irradiation selectively destroyed the complex-targeted breast cancer cells without harming receptor-free cells. The cell death was effectuated without the need of internalization of SWNTs by the cancer cells, a finding that has not been reported previously. We have demonstrated that the HER2 IgY-SWNT complex specifically targeted HER2-expressing SK-BR-3 cells but not receptor-negative MCF-7 cells. The complex can be potentially used for both detection and selective photothermal ablation of receptor-positive breast cancer cells without the need of internalization by the cells. Thus, the unique intrinsic properties of SWNTs combined with high specificity and sensitivity of IgY antibodies can lead to new strategies for cancer detection and therapy.
Explicit attention interferes with selective emotion processing in human extrastriate cortex.

PubMed

Schupp, Harald T; Stockburger, Jessica; Bublatzky, Florian; Junghöfer, Markus; Weike, Almut I; Hamm, Alfons O

2007-02-22

Brain imaging and event-related potential studies provide strong evidence that emotional stimuli guide selective attention in visual processing. A reflection of the emotional attention capture is the increased Early Posterior Negativity (EPN) for pleasant and unpleasant compared to neutral images (approximately 150-300 ms poststimulus). The present study explored whether this early emotion discrimination reflects an automatic phenomenon or is subject to interference by competing processing demands. Thus, emotional processing was assessed while participants performed a concurrent feature-based attention task varying in processing demands. Participants successfully performed the primary visual attention task as revealed by behavioral performance and selected event-related potential components (Selection Negativity and P3b). Replicating previous results, emotional modulation of the EPN was observed in a task condition with low processing demands. In contrast, pleasant and unpleasant pictures failed to elicit increased EPN amplitudes compared to neutral images in more difficult explicit attention task conditions. Further analyses determined that even the processing of pleasant and unpleasant pictures high in emotional arousal is subject to interference in experimental conditions with high task demand. Taken together, performing demanding feature-based counting tasks interfered with differential emotion processing indexed by the EPN. The present findings demonstrate that taxing processing resources by a competing primary visual attention task markedly attenuated the early discrimination of emotional from neutral picture contents. Thus, these results provide further empirical support for an interference account of the emotion-attention interaction under conditions of competition. Previous studies revealed the interference of selective emotion processing when attentional resources were directed to locations of explicitly task-relevant stimuli. The present data suggest that interference of emotion processing by competing task demands is a more general phenomenon extending to the domain of feature-based attention. Furthermore, the results are inconsistent with the notion of effortlessness, i.e., early emotion discrimination despite concurrent task demands. These findings implicate to assess the presumed automatic nature of emotion processing at the level of specific aspects rather than considering automaticity as an all-or-none phenomenon.
Explicit attention interferes with selective emotion processing in human extrastriate cortex

PubMed Central

Schupp, Harald T; Stockburger, Jessica; Bublatzky, Florian; Junghöfer, Markus; Weike, Almut I; Hamm, Alfons O

2007-01-01

Background Brain imaging and event-related potential studies provide strong evidence that emotional stimuli guide selective attention in visual processing. A reflection of the emotional attention capture is the increased Early Posterior Negativity (EPN) for pleasant and unpleasant compared to neutral images (~150–300 ms poststimulus). The present study explored whether this early emotion discrimination reflects an automatic phenomenon or is subject to interference by competing processing demands. Thus, emotional processing was assessed while participants performed a concurrent feature-based attention task varying in processing demands. Results Participants successfully performed the primary visual attention task as revealed by behavioral performance and selected event-related potential components (Selection Negativity and P3b). Replicating previous results, emotional modulation of the EPN was observed in a task condition with low processing demands. In contrast, pleasant and unpleasant pictures failed to elicit increased EPN amplitudes compared to neutral images in more difficult explicit attention task conditions. Further analyses determined that even the processing of pleasant and unpleasant pictures high in emotional arousal is subject to interference in experimental conditions with high task demand. Taken together, performing demanding feature-based counting tasks interfered with differential emotion processing indexed by the EPN. Conclusion The present findings demonstrate that taxing processing resources by a competing primary visual attention task markedly attenuated the early discrimination of emotional from neutral picture contents. Thus, these results provide further empirical support for an interference account of the emotion-attention interaction under conditions of competition. Previous studies revealed the interference of selective emotion processing when attentional resources were directed to locations of explicitly task-relevant stimuli. The present data suggest that interference of emotion processing by competing task demands is a more general phenomenon extending to the domain of feature-based attention. Furthermore, the results are inconsistent with the notion of effortlessness, i.e., early emotion discrimination despite concurrent task demands. These findings implicate to assess the presumed automatic nature of emotion processing at the level of specific aspects rather than considering automaticity as an all-or-none phenomenon. PMID:17316444
Starting off on the right foot: strong right-footers respond faster with the right foot to positive words and with the left foot to negative words

PubMed Central

de la Vega, Irmgard; Graebe, Julia; Härtner, Leonie; Dudschig, Carolin; Kaup, Barbara

2015-01-01

Recent studies have provided evidence for an association between valence and left/right modulated by handedness, which is predicted by the body-specificity hypothesis (Casasanto, 2009) and also reflected in response times. We investigated whether such a response facilitation can also be observed with foot responses. Right-footed participants classified positive and negative words according to their valence by pressing a key with their left or right foot. A significant interaction between valence and foot only emerged in the by-items analysis. However, when dividing participants into two groups depending on the strength of their footedness, an interaction between valence and left/right was observed for strong right-footers, who responded faster with the right foot to positive words, and with the left foot to negative words. No interaction emerged for weak right-footers. The results strongly support the assumption that fluency lies at the core of the association between valence and left/right. PMID:25852609
Selective Imaging of Gram-Negative and Gram-Positive Microbiotas in the Mouse Gut.

PubMed

Wang, Wei; Zhu, Yuntao; Chen, Xing

2017-08-01

The diverse gut microbial communities are crucial for host health. How the interactions between microbial communities and between host and microbes influence the host, however, is not well understood. To facilitate gut microbiota research, selective imaging of specific groups of microbiotas in the gut is of great utility but remains technically challenging. Here we present a chemical approach that enables selective imaging of Gram-negative and Gram-positive microbiotas in the mouse gut by exploiting their distinctive cell wall components. Cell-selective labeling is achieved by the combined use of metabolic labeling of Gram-negative bacterial lipopolysaccharides with a clickable azidosugar and direct labeling of Gram-positive bacteria with a vancomycin-derivatized fluorescent probe. We demonstrated this strategy by two-color fluorescence imaging of Gram-negative and Gram-positive gut microbiotas in the mouse intestines. This chemical method should be broadly applicable to different gut microbiota research fields and other bacterial communities studied in microbiology.
Evolution of the complementary sex-determination gene of honey bees: balancing selection and trans-species polymorphisms.

PubMed

Cho, Soochin; Huang, Zachary Y; Green, Daniel R; Smith, Deborah R; Zhang, Jianzhi

2006-11-01

The mechanism of sex determination varies substantively among evolutionary lineages. One important mode of genetic sex determination is haplodiploidy, which is used by approximately 20% of all animal species, including >200,000 species of the entire insect order Hymenoptera. In the honey bee Apis mellifera, a hymenopteran model organism, females are heterozygous at the csd (complementary sex determination) locus, whereas males are hemizygous (from unfertilized eggs). Fertilized homozygotes develop into sterile males that are eaten before maturity. Because homozygotes have zero fitness and because common alleles are more likely than rare ones to form homozygotes, csd should be subject to strong overdominant selection and negative frequency-dependent selection. Under these selective forces, together known as balancing selection, csd is expected to exhibit a high degree of intraspecific polymorphism, with long-lived alleles that may be even older than the species. Here we sequence the csd genes as well as randomly selected neutral genomic regions from individuals of three closely related species, A. mellifera, Apis cerana, and Apis dorsata. The polymorphic level is approximately seven times higher in csd than in the neutral regions. Gene genealogies reveal trans-species polymorphisms at csd but not at any neutral regions. Consistent with the prediction of rare-allele advantage, nonsynonymous mutations are found to be positively selected in csd only in early stages after their appearances. Surprisingly, three different hypervariable repetitive regions in csd are present in the three species, suggesting variable mechanisms underlying allelic specificities. Our results provide a definitive demonstration of balancing selection acting at the honey bee csd gene, offer insights into the molecular determinants of csd allelic specificities, and help avoid homozygosity in bee breeding.
Chess masters show a hallmark of face processing with chess.

PubMed

Boggan, Amy L; Bartlett, James C; Krawczyk, Daniel C

2012-02-01

Face processing has several distinctive hallmarks that researchers have attributed either to face-specific mechanisms or to extensive experience distinguishing faces. Here, we examined the face-processing hallmark of selective attention failure--as indexed by the congruency effect in the composite paradigm--in a domain of extreme expertise: chess. Among 27 experts, we found that the congruency effect was equally strong with chessboards and faces. Further, comparing these experts with recreational players and novices, we observed a trade-off: Chess expertise was positively related to the congruency effect with chess yet negatively related to the congruency effect with faces. These and other findings reveal a case of expertise-dependent, facelike processing of objects of expertise and suggest that face and expert-chess recognition share common processes.
Funneled focusing of planar acoustic waves utilizing the metamaterial properties of an acoustic lens

NASA Astrophysics Data System (ADS)

Walker, E.; Reyes, D.; Rojas, M. M.; Krokhin, A.; Neogi, A.

2014-02-01

Metamaterial acoustic lenses are acoustic devices based on phononic crystal structures that take advantage of negative or near-zero indices of refraction. These unique properties arise due to either the antiparallel direction of the phase and group velocity or strongly anisotropic dispersion characteristics, usually above the first transmission band. In this study, we utilize an FDTD program to examine two phononic lenses that utilize anisotropic effects available in their second band to collimate and focus acoustic waves from a plane-wave source with a k00 wavevector. The phononic crystals consist of stainless steel rods arranged in a square lattice with water as the ambient material. Results show collimation and focusing in the second band for select frequencies, fc ± 0.005𝑓𝑐.
Emerging biomarkers for cancer immunotherapy in melanoma.

PubMed

Axelrod, Margaret L; Johnson, Douglas B; Balko, Justin M

2017-09-14

The treatment and prognosis of metastatic melanoma has changed substantially since the advent of novel immune checkpoint inhibitors (ICI), agents that enhance the anti-tumor immune response. Despite the success of these agents, clinically actionable biomarkers to aid patient and regimen selection are lacking. Herein, we summarize and review the evidence for candidate biomarkers of response to ICIs in melanoma. Many of these candidates can be examined as parts of a known molecular pathway of immune response, while others are clinical in nature. Due to the ability of ICIs to illicit dramatic and durable responses, well-validated biomarkers that can be effectively implemented in the clinic will require strong negative predictive values that do not limit patients with who may benefit from ICI therapy. Copyright © 2017 Elsevier Ltd. All rights reserved.

The temporal deployment of emotion regulation strategies during negative emotional episodes.

PubMed

Kalokerinos, Elise K; Résibois, Maxime; Verduyn, Philippe; Kuppens, Peter

2017-04-01

Time is given a central place in theoretical models of emotion regulation (Gross, 1998, 2015), but key questions regarding the role of time remain unanswered. We investigated 2 such unanswered questions. First, we explored when different emotion regulation strategies were used within the course of an emotional episode in daily life. Second, we investigated the association between the temporal deployment of strategies and negative emotional experience. We conducted a daily diary study in which participants (N = 74) drew an intensity profile depicting the temporal unfolding of their negative emotional experience across daily events (N = 480), and mapped their usage of emotion regulation strategies onto this intensity profile. Strategies varied in their temporal deployment, with suppression and rumination occurring more at the beginning of the episode, and reappraisal and distraction occurring more toward the end of the episode. Strategies also varied in their association with negative emotion: rumination was positively associated with negative emotion, and reappraisal and distraction were negatively associated with negative emotion. Finally, both rumination and reappraisal interacted with time to predict negative emotional experience. Rumination was more strongly positively associated with negative emotions at the end of the episode than the beginning, but reappraisal was more strongly negatively associated with negative emotion at the beginning of the episode than the end. These findings highlight the importance of accounting for timing in the study of emotion regulation, as well as the necessity of studying these temporal processes in daily life. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
Patterns and rates of intron divergence between humans and chimpanzees

PubMed Central

Gazave, Elodie; Marqués-Bonet, Tomàs; Fernando, Olga; Charlesworth, Brian; Navarro, Arcadi

2007-01-01

Background Introns, which constitute the largest fraction of eukaryotic genes and which had been considered to be neutral sequences, are increasingly acknowledged as having important functions. Several studies have investigated levels of evolutionary constraint along introns and across classes of introns of different length and location within genes. However, thus far these studies have yielded contradictory results. Results We present the first analysis of human-chimpanzee intron divergence, in which differences in the number of substitutions per intronic site (Ki) can be interpreted as the footprint of different intensities and directions of the pressures of natural selection. Our main findings are as follows: there was a strong positive correlation between intron length and divergence; there was a strong negative correlation between intron length and GC content; and divergence rates vary along introns and depending on their ordinal position within genes (for instance, first introns are more GC rich, longer and more divergent, and divergence is lower at the 3' and 5' ends of all types of introns). Conclusion We show that the higher divergence of first introns is related to their larger size. Also, the lower divergence of short introns suggests that they may harbor a relatively greater proportion of regulatory elements than long introns. Moreover, our results are consistent with the presence of functionally relevant sequences near the 5' and 3' ends of introns. Finally, our findings suggest that other parts of introns may also be under selective constraints. PMID:17309804
BREEDING AND GENETICS SYMPOSIUM: Resilience and lessons from studies in genetics of heat stress.

PubMed

Misztal, I

2017-04-01

Production environments are expected to change, mostly to a hotter climate but also possibly more extreme and drier. Can the current generation of farm animals cope with the changes or should it be specifically selected for changing conditions? In general, genetic selection produces animals with a smaller environmental footprint but also with smaller environmental flexibility. Some answers are coming from heat-stress research across species, with heat tolerance partly understood as a greater environmental flexibility. Specific studies in various species show the complexities of defining and selecting for heat tolerance. In Holsteins, the genetic component for effect of heat stress on production approximately doubles in second and quadruples in third parity. Cows with elevated body temperature have the greatest production under heat stress but probably are at risk for increased mortality. In hot but less intensive environments, the effect of heat stress on production is minimal, although the negative effect on fertility remains. Mortality peaks under heat stress and increases with parity. In Angus, the effect of heat stress is stronger only in selected regions, probably because of adaptation of calving seasons to local conditions and crossbreeding. Genetically, the direct effect shows variability because of heat stress, but the maternal effect does not, probably because dams shield calves from environmental challenges. In pigs, the effect of heat stress is strong for commercial farms but almost nothing for nucleus farms, which have lower pig density and better heat abatement. Under intensive management, heat stress is less evident in drier environments because of more efficient cooling. A genetic component of heat stress exists, but it is partly masked by improving management and selection based on data from elite farms. Genetic selection may provide superior identification of heat-tolerant animals, but a few cycles may be needed for clear results. Also, simple traits exist that are strongly related to heat stress (e.g., slick hair in dairy cattle and shedding intensity in Angus). Defining resilience may be difficult, especially when masked by improving environment. Under climate change, the current selection strategies may be adequate if they 1) are accompanied by constantly improving management, 2) use commercial data, and 3) include traits important under climate change (e.g., mortality).
Evolution of mating system and the genetic covariance between male and female investment in Clarkia (onagraceae): selfing opposes the evolution of trade-offs.

PubMed

Mazer, Susan J; Delesalle, Véronique A; Paz, Horacio

2007-01-01

Sex allocation theory has assumed that hermaphroditic species exhibit strong genetically based trade-offs between investment in male and female function. The potential effects of mating system on the evolution of this genetic covariance, however, have not been explored. We have challenged the assumption of a ubiquitous trade-off between male and female investment by arguing that in highly self-fertilizing species, stabilizing natural selection should favor highly efficient ratios of male to female gametes. In flowering plants, the result of such selection would be similar pollen:ovule (P:O) ratios across selfing genotypes, precluding a negative genetic correlation (r(g)) between pollen and ovule production per flower. Moreover, if selfing genotypes with similar P:O ratios differ in total gametic investment per flower, a positive r(g) between pollen and ovule production would be observed. In outcrossers, by contrast, male- and female-biased flowers and genotypes may have equal fitness and coexist at evolutionary equilibrium. In the absence of strong stabilizing selection on the P:O ratio, selection on this trait will be relaxed, resulting in independence or resource-based trade-offs between male and female investment. To test this prediction, we conducted artificial selection on pollen and ovule production per flower in two sister species with contrasting mating systems. The predominantly self-fertilizing species (Clarkia exilis) consistently exhibited a significant positive r(g) between pollen and ovule production while the outcrossing species (C. unguiculata) exhibited either a trade-off or independence between these traits. Clarkia exilis also exhibited much more highly canalized gender expression than C. unguiculata. Selection on pollen and ovule production resulted in little correlated change in the P:O ratio in the selfing exilis, while dramatic changes in the P:O ratio were observed in unguiculata. To test the common prediction that floral attractiveness should be positively genetically correlated with investment in male function, we examined the response of petal area to selection on pollen and ovule production and found that petal area was not consistently genetically correlated with gender expression in either species. Our results suggest that the joint evolutionary trajectory of primary sexual traits in hermaphroditic species will be affected by their mating systems; this should be taken into account in future theoretical and comparative empirical investigations.
Selective attention to a facial feature with and without facial context: an ERP-study.

PubMed

Wijers, A A; Van Besouw, N J P; Mulder, G

2002-04-01

The present experiment addressed the question whether selectively attending to a facial feature (mouth shape) would benefit from the presence of a correct facial context. Subjects attended selectively to one of two possible mouth shapes belonging to photographs of a face with a happy or sad expression, respectively. These mouths were presented randomly either in isolation, embedded in the original photos, or in an exchanged facial context. The ERP effect of attending mouth shape was a lateral posterior negativity, anterior positivity with an onset latency of 160-200 ms; this effect was completely unaffected by the type of facial context. When the mouth shape and the facial context conflicted, this resulted in a medial parieto-occipital positivity with an onset latency of 180 ms, independent of the relevance of the mouth shape. Finally, there was a late (onset at approx. 400 ms) expression (happy vs. sad) effect, which was strongly lateralized to the right posterior hemisphere and was most prominent for attended stimuli in the correct facial context. For the isolated mouth stimuli, a similarly distributed expression effect was observed at an earlier latency range (180-240 ms). These data suggest the existence of separate, independent and neuroanatomically segregated processors engaged in the selective processing of facial features and the detection of contextual congruence and emotional expression of face stimuli. The data do not support that early selective attention processes benefit from top-down constraints provided by the correct facial context.
Comparative analysis of magnetic resonance in the polaron pair recombination and the triplet exciton-polaron quenching models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mkhitaryan, V. V.; Danilovic, D.; Hippola, C.

We present a comparative theoretical study of magnetic resonance within the polaron pair recombination (PPR) and the triplet exciton-polaron quenching (TPQ) models. Both models have been invoked to interpret the photoluminescence detected magnetic resonance (PLDMR) results in π-conjugated materials and devices. We show that resonance line shapes calculated within the two models differ dramatically in several regards. First, in the PPR model, the line shape exhibits unusual behavior upon increasing the microwave power: it evolves from fully positive at weak power to fully negative at strong power. In contrast, in the TPQ model, the PLDMR is completely positive, showing amore » monotonic saturation. Second, the two models predict different dependencies of the resonance signal on the photoexcitation power, PL. At low PL, the resonance amplitude Δ I/I is ∝ PL within the PPR model, while it is ∝ P2L crossing over to P3L within the TPQ model. On the physical level, the differences stem from different underlying spin dynamics. Most prominently, a negative resonance within the PPR model has its origin in the microwave-induced spin-Dicke effect, leading to the resonant quenching of photoluminescence. The spin-Dicke effect results from the spin-selective recombination, leading to a highly correlated precession of the on-resonance pair partners under the strong microwave power. This effect is not relevant for TPQ mechanism, where the strong zero-field splitting renders the majority of triplets off resonance. On the technical level, the analytical evaluation of the line shapes for the two models is enabled by the fact that these shapes can be expressed via the eigenvalues of a complex Hamiltonian. This bypasses the necessity of solving the much larger complex linear system of the stochastic Liouville equations. Lastly, our findings pave the way towards a reliable discrimination between the two mechanisms via cw PLDMR.« less
Comparative analysis of magnetic resonance in the polaron pair recombination and the triplet exciton-polaron quenching models

DOE PAGES

Mkhitaryan, V. V.; Danilovic, D.; Hippola, C.; ...

2018-01-03

We present a comparative theoretical study of magnetic resonance within the polaron pair recombination (PPR) and the triplet exciton-polaron quenching (TPQ) models. Both models have been invoked to interpret the photoluminescence detected magnetic resonance (PLDMR) results in π-conjugated materials and devices. We show that resonance line shapes calculated within the two models differ dramatically in several regards. First, in the PPR model, the line shape exhibits unusual behavior upon increasing the microwave power: it evolves from fully positive at weak power to fully negative at strong power. In contrast, in the TPQ model, the PLDMR is completely positive, showing amore » monotonic saturation. Second, the two models predict different dependencies of the resonance signal on the photoexcitation power, PL. At low PL, the resonance amplitude Δ I/I is ∝ PL within the PPR model, while it is ∝ P2L crossing over to P3L within the TPQ model. On the physical level, the differences stem from different underlying spin dynamics. Most prominently, a negative resonance within the PPR model has its origin in the microwave-induced spin-Dicke effect, leading to the resonant quenching of photoluminescence. The spin-Dicke effect results from the spin-selective recombination, leading to a highly correlated precession of the on-resonance pair partners under the strong microwave power. This effect is not relevant for TPQ mechanism, where the strong zero-field splitting renders the majority of triplets off resonance. On the technical level, the analytical evaluation of the line shapes for the two models is enabled by the fact that these shapes can be expressed via the eigenvalues of a complex Hamiltonian. This bypasses the necessity of solving the much larger complex linear system of the stochastic Liouville equations. Lastly, our findings pave the way towards a reliable discrimination between the two mechanisms via cw PLDMR.« less
Comparative analysis of magnetic resonance in the polaron pair recombination and the triplet exciton-polaron quenching models

NASA Astrophysics Data System (ADS)

Mkhitaryan, V. V.; Danilović, D.; Hippola, C.; Raikh, M. E.; Shinar, J.

2018-01-01

We present a comparative theoretical study of magnetic resonance within the polaron pair recombination (PPR) and the triplet exciton-polaron quenching (TPQ) models. Both models have been invoked to interpret the photoluminescence detected magnetic resonance (PLDMR) results in π -conjugated materials and devices. We show that resonance line shapes calculated within the two models differ dramatically in several regards. First, in the PPR model, the line shape exhibits unusual behavior upon increasing the microwave power: it evolves from fully positive at weak power to fully negative at strong power. In contrast, in the TPQ model, the PLDMR is completely positive, showing a monotonic saturation. Second, the two models predict different dependencies of the resonance signal on the photoexcitation power, PL. At low PL, the resonance amplitude Δ I /I is ∝PL within the PPR model, while it is ∝PL2 crossing over to PL3 within the TPQ model. On the physical level, the differences stem from different underlying spin dynamics. Most prominently, a negative resonance within the PPR model has its origin in the microwave-induced spin-Dicke effect, leading to the resonant quenching of photoluminescence. The spin-Dicke effect results from the spin-selective recombination, leading to a highly correlated precession of the on-resonance pair partners under the strong microwave power. This effect is not relevant for TPQ mechanism, where the strong zero-field splitting renders the majority of triplets off resonance. On the technical level, the analytical evaluation of the line shapes for the two models is enabled by the fact that these shapes can be expressed via the eigenvalues of a complex Hamiltonian. This bypasses the necessity of solving the much larger complex linear system of the stochastic Liouville equations. Our findings pave the way towards a reliable discrimination between the two mechanisms via cw PLDMR.
Which leaf mechanical traits correlate with insect herbivory among feeding guilds?

PubMed Central

Caldwell, Elizabeth; Read, Jennifer; Sanson, Gordon D.

2016-01-01

Background and Aims There is abundant evidence that leaf mechanical traits deter feeding by insect herbivores, but little is known about which particular traits contribute to defence across feeding guilds. We investigated the contribution of multiple mechanical traits from shear, punch and tear tests to herbivore deterrence across feeding guilds. Methods Visible damage from miners and external chewers was measured and sucker feeding density estimated in mature leaves of 20 species of forest shrubs and small trees. Cafeteria trials were undertaken using a generalist chewer (larvae of Epiphyas postvittana, Lepidoptera). Damage was compared with leaf mechanical traits and associated nutrient and chemical defence traits. Key Results Damage by external chewers in the field and by E. postvittana correlated negatively with mechanical traits. Hierarchical partitioning analysis indicated that the strongest independent contribution to chewing damage was by the material trait of specific work to shear, with 68 % of total variance explained by the combination of specific work to shear (alone explaining 54 %) and tannin activity in a regression model. Mining damage did not correlate with mechanical traits, probably because miners can avoid tissues that generate high strength and toughness in mature leaves. Mechanical traits correlated more strongly with chewing damage in the field than chemical defences (total phenolics and tannin activity) and nutrients (nitrogen and water), but nutrients correlated strongly with diet selection in the cafeteria trial. Surprisingly, sucker feeding density correlated positively with mechanical traits and negatively with nutrients. Conclusions Mechanical traits of mature leaves influenced insect feeding guilds differentially, reflecting differences in life history and feeding modes. For external chewers, energy (work) to fracture in shearing tests, at both structural and material levels, was strongly predictive of damage. Knowing which leaf mechanical traits influence insect feeding, and in which guilds, is important to our wider understanding of plant–herbivore interactions. PMID:26715468
The decision to vaccinate or not during the H1N1 pandemic: selecting the lesser of two evils?

PubMed

Ashbaugh, Andrea R; Herbert, Christophe F; Saimon, Elena; Azoulay, Nelson; Olivera-Figueroa, Lening; Brunet, Alain

2013-01-01

With the release of the H1N1 vaccine, there was much controversy surrounding its use despite strong encouragements to be vaccinated in the media. Though studies have examined factors influencing people's decision to be vaccinated, few have focused on how general beliefs about the world or where an individual gathers information might influence that decision. A cross-sectional web-based survey (N = 817) was conducted during the H1N1 outbreak after the vaccine was available. Variables examined included sociodemographic information, health related behaviours, specific beliefs concerning the H1N1 virus and its vaccine, as well as general beliefs, such as fear of contamination, intolerance of uncertainty, emotional states, coping behaviour, and the source of information concerning the virus. Three converging statistical methods were used to examine the associations - analysis of variance, logistic regression, and recursive partition modelling. The most consistent and strongest association was that negative beliefs about the H1N1 vaccine (e.g. fear of its side effects) was related to the decision not to be vaccinated, whereas beliefs about the dangers of the H1N1 virus was related to the decision to be vaccinated. Most notably, having very strong negative beliefs about the vaccine was a more powerful predictor than even strong beliefs about the dangers of the H1N1 virus. Furthermore, obtaining information from the Internet, as compared to more traditional sources of information (e.g., TV, newspapers) was related to the decision not to be vaccinated. These results are consistent with the Health Belief Model. Importantly they suggest that during future pandemics public health officials should not only discuss the dangers of the pandemic but also (i) take additional steps to reassure the public about the safety of vaccines and (ii) monitor the information disseminated over the Internet rather than strictly relying on the more traditional mass media.
Evolution of Drosophila resistance against different pathogens and infection routes entails no detectable maintenance costs.

PubMed

Faria, Vítor G; Martins, Nelson E; Paulo, Tânia; Teixeira, Luís; Sucena, Élio; Magalhães, Sara

2015-11-01

Pathogens exert a strong selective pressure on hosts, entailing host adaptation to infection. This adaptation often affects negatively other fitness-related traits. Such trade-offs may underlie the maintenance of genetic diversity for pathogen resistance. Trade-offs can be tested with experimental evolution of host populations adapting to parasites, using two approaches: (1) measuring changes in immunocompetence in relaxed-selection lines and (2) comparing life-history traits of evolved and control lines in pathogen-free environments. Here, we used both approaches to examine trade-offs in Drosophila melanogaster populations evolving for over 30 generations under infection with Drosophila C Virus or the bacterium Pseudomonas entomophila, the latter through different routes. We find that resistance is maintained after up to 30 generations of relaxed selection. Moreover, no differences in several classical life-history traits between control and evolved populations were found in pathogen-free environments, even under stresses such as desiccation, nutrient limitation, and high densities. Hence, we did not detect any maintenance costs associated with resistance to pathogens. We hypothesize that extremely high selection pressures commonly used lead to the disproportionate expression of costs relative to their actual occurrence in natural systems. Still, the maintenance of genetic variation for pathogen resistance calls for an explanation. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.
Darwinian algorithms and the Wason selection task: a factorial analysis of social contract selection task problems.

PubMed

Platt, R D; Griggs, R A

1993-08-01

In four experiments with 760 subjects, the present study examined Cosmides' Darwinian algorithm theory of reasoning: specifically, its explanation of facilitation on the Wason selection task. The first experiment replicated Cosmides' finding of facilitation for social contract versions of the selection task, using both her multiple-problem format and a single-problem format. Experiment 2 examined performance on Cosmides' three main social contract problems while manipulating the perspective of the subject and the presence and absence of cost-benefit information. The presence of cost-benefit information improved performance in two of the three problems while the perspective manipulation had no effect. In Experiment 3, the cost-benefit effect was replicated; and performance on one of the three problems was enhanced by the presence of explicit negatives on the NOT-P and NOT-Q cards. Experiment 4 examined the role of the deontic term "must" in the facilitation observed for two of the social contract problems. The presence of "must" led to a significant improvement in performance. The results of these experiments are strongly supportive of social contract theory in that cost-benefit information is necessary for substantial facilitation to be observed in Cosmides' problems. These findings also suggest the presence of other cues that can help guide subjects to a deontic social contract interpretation when the social contract nature of the problem is not clear.
Non-Thermal Atmospheric Pressure Plasma Preferentially Induces Apoptosis in p53-Mutated Cancer Cells by Activating ROS Stress-Response Pathways

PubMed Central

Ma, Yonghao; Ha, Chang Seung; Hwang, Seok Won; Lee, Hae June; Kim, Gyoo Cheon; Lee, Kyo-Won; Song, Kiwon

2014-01-01

Non-thermal atmospheric pressure plasma (NTAPP) is an ionized gas at room temperature and has potential as a new apoptosis-promoting cancer therapy that acts by generating reactive oxygen species (ROS). However, it is imperative to determine its selectivity and standardize the components and composition of NTAPP. Here, we designed an NTAPP-generating apparatus combined with a He gas feeding system and demonstrated its high selectivity toward p53-mutated cancer cells. We first determined the proper conditions for NTAPP exposure to selectively induce apoptosis in cancer cells. The apoptotic effect of NTAPP was greater for p53-mutated cancer cells; artificial p53 expression in p53-negative HT29 cells decreased the pro-apoptotic effect of NTAPP. We also examined extra- and intracellular ROS levels in NTAPP-treated cells to deduce the mechanism of NTAPP action. While NTAPP-mediated increases in extracellular nitric oxide (NO) did not affect cell viability, intracellular ROS increased under NTAPP exposure and induced apoptotic cell death. This effect was dose-dependently reduced following treatment with ROS scavengers. NTAPP induced apoptosis even in doxorubicin-resistant cancer cell lines, demonstrating the feasibility of NTAPP as a potent cancer therapy. Collectively, these results strongly support the potential of NTAPP as a selective anticancer treatment, especially for p53-mutated cancer cells. PMID:24759730
The Relationship between Runs of Homozygosity and Inbreeding in Jersey Cattle under Selection

PubMed Central

Kim, Eui-Soo; Sonstegard, Tad S.; Van Tassell, Curtis P.; Wiggans, George; Rothschild, Max F.

2015-01-01

Inbreeding is often an inevitable outcome of strong directional artificial selection but on average it reduces population fitness with increased frequency of recessive deleterious alleles. Runs of homozygosity (ROH) representing genomic autozygosity that occur from mating between selected and genomically related individuals may be able to reveal the regions affecting fitness. To examine the influence of genomic autozygosity on fitness, we used a genome-wide association test to evaluate potential negative correlations between ROH and daughter pregnancy rate (DPR) or somatic cell score (SCS) in US Jersey cattle. In addition, relationships between changes of local ROH and inbreeding coefficients (F) were assessed to locate genomic regions with increased inbreeding. Despite finding some decreases in fertility associated with incremental increases in F, most emerging local ROH were not significantly associated with DPR or SCS. Furthermore, the analyses of ROH could be approximated with the most frequent haplotype(s), including the associations of ROH and F or traits. The analysis of the most frequent haplotype revealed that associations of ROH and fertility could be accounted for by the additive genetic effect on the trait. Thus, we suggest that a change of autozygosity is more likely to demonstrate footprints of selected haplotypes for production rather than highlight the possible increased local autozygosity of a recessive detrimental allele resulting from the mating between closely related animals in Jersey cattle. PMID:26154171
Trends along the debt-income axis: implications for medical students' selections of family practice careers.

PubMed

Rosenthal, M P; Marquette, P A; Diamond, J J

1996-06-01

To examine whether medical students' levels of debt have an influence on selection of family practice careers, independent of other factors. Data from the Jefferson Longitudinal Study were analyzed for 1,350 graduates from the classes of 1987-1993 at Jefferson Medical College of Thomas Jefferson University; a focused analysis for 326 graduates from the classes of 1992 and 1993 was specifically performed to identify recent trends. A binary logistic regression equation was used to predict the probability of a graduate's entrance into a family practice residency based on first-year preference for family practice, income expectation, debt level, age, and gender. A high level of indebtedness (at least $75,000) was a significant independent predictor of specialty choice (away from family practice); first-year preference for family practice and income expectation were also significant independent predictors. Combining these three factors (debt, specialty preference, and income expectation) led to a greater than 12-fold difference in specialty selection of family practice. Notably, 36% of the students graduating in 1992-1993 had debts of at least $75,000, more than three times the percentage in the classes graduating in 1987-1989. High levels of debt had a significant negative effect on family practice specialty, choice among recent Jefferson graduates. An increase in the number of students with such debt carries strong implications for the selection of careers in family practice.
Selection on parental performance opposes selection for larger body mass in a wild population of blue tits.

PubMed

Thomson, Caroline E; Bayer, Florian; Crouch, Nicholas; Farrell, Samantha; Heap, Elizabeth; Mittell, Elizabeth; Zurita-Cassinello, Mar; Hadfield, Jarrod D

2017-03-01

There is abundant evidence in many taxa for positive directional selection on body size, and yet little evidence for microevolutionary change. In many species, variation in body size is partly determined by the actions of parents, so a proposed explanation for stasis is the presence of a negative genetic correlation between direct and parental effects. Consequently, selecting genes for increased body size would result in a correlated decline in parental effects, reducing body size in the following generation. We show that these arguments implicitly assume that parental care is cost free, and that including a cost alters the predicted genetic architectures needed to explain stasis. Using a large cross-fostered population of blue tits, we estimate direct selection on parental effects for body mass, and show it is negative. Negative selection is consistent with a cost to parental care, mainly acting through a reduction in current fecundity rather than survival. Under these conditions, evolutionary stasis is possible for moderately negative genetic correlations between direct and parental effects. This is in contrast to the implausibly extreme correlations needed when care is assumed to be cost-free. Thus, we highlight the importance of accounting correctly for complete selection acting on traits across generations. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.
A comparative evaluation of in vitro skin sensitisation tests: the human cell-line activation test (h-CLAT) versus the local lymph node assay (LLNA).

PubMed

Ashikaga, Takao; Sakaguchi, Hitoshi; Sono, Sakiko; Kosaka, Nanae; Ishikawa, Makie; Nukada, Yuko; Miyazawa, Masaaki; Ito, Yuichi; Nishiyama, Naohiro; Itagaki, Hiroshi

2010-08-01

We previously developed the human cell-line activation test (h-CLAT) in vitro skin sensitisation test, based on our reported finding that a 24-hour exposure of THP-1 cells (a human monocytic leukaemia cell line) to sensitisers is sufficient to induce the augmented expression of CD86 and CD54. The aim of this study is to confirm the predictive value of h-CLAT for skin sensitisation activity by employing a larger number of test chemicals. One hundred chemicals were selected, according to their categorisation in the local lymph node assay (LLNA), as being: extreme, strong, moderate and weak sensitisers, and non-sensitisers. The correlation of the h-CLAT results with the LLNA results was 84%. There were some false negatives (e.g. benzoyl peroxide, hexyl cinnamic aldehyde) and some false positives (e.g. 1-bromobutane, diethylphthalate). Eight out of the 9 false negatives (89%) were water-insoluble chemicals. The h-CLAT could positively predict not only extreme and strong sensitisers, but also moderate and weak sensitisers, though the detection rates of weak sensitisers and non-sensitisers were comparatively low. Some sensitisers enhanced both CD86 and CD54 levels, and some enhanced the level of only one of them. The use of the combination of CD86 and CD54 induction as a positive indicator, improved the accuracy of the test. In conclusion, the h-CLAT is expected to be a useful cell-based in vitro method for predicting skin sensitisation potential. 2010 FRAME.
Negative frequency-dependent selection between Pasteuria penetrans and its host Meloidogyne arenaria

USDA-ARS?s Scientific Manuscript database

In negative frequency-dependant selection (NFDS), parasite genotypes capable of infecting the numerically dominant host genotype are favored, while host genotypes resistant to the dominant parasite genotype are favored, creating a cyclical pattern of resistant genotypes in the host population and, a...
Cognitive correlates of anxious and depressive symptomatology: an examination of the Helplessness/Hopelessness model.

PubMed

Waikar, S V; Craske, M G

1997-01-01

Expectancies about future life events were assessed in anxious and depressed patients to test predictions of the Helplessness/Hopelessness model of anxiety and depression (Alloy, Kelly, Mineka, & Clements, 1990). In addition to expectancies for future events, patients from affective and anxiety treatment clinics completed anxiety and depression symptom ratings and positive and negative affects scales. Findings revealed partial support for the model. Negative outcome and helplessness expectancies were related specifically to depression. Cognitions regarding future positive events were interrelated and associated with symptom measures more strongly than were cognitions regarding negative events. Additionally, positive affects was more strongly related to depression than to anxiety symptom ratings. Implications and limitations of these findings are discussed.
The positive relationships between plant coverage, species richness, and aboveground biomass are ubiquitous across plant growth forms in semi-steppe rangelands.

PubMed

Sanaei, Anvar; Ali, Arshad; Chahouki, Mohammad Ali Zare

2018-01-01

The positive relationships between biodiversity and aboveground biomass are important for biodiversity conservation and greater ecosystem functioning and services that humans depend on. However, the interaction effects of plant coverage and biodiversity on aboveground biomass across plant growth forms (shrubs, forbs and grasses) in natural rangelands are poorly studied. Here, we hypothesized that, while accounting for environmental factors and disturbance intensities, the positive relationships between plant coverage, biodiversity, and aboveground biomass are ubiquitous across plant growth forms in natural rangelands. We applied structural equation models (SEMs) using data from 735 quadrats across 35 study sites in semi-steppe rangelands in Iran. The combination of plant coverage and species richness rather than Shannon's diversity or species diversity (a latent variable of species richness and evenness) substantially enhance aboveground biomass across plant growth forms. In all selected SEMs, plant coverage had a strong positive direct effect on aboveground biomass (β = 0.72 for shrubs, 0.84 for forbs and 0.80 for grasses), followed by a positive effect of species richness (β = 0.26 for shrubs, 0.05 for forbs and 0.09 for grasses), and topographic factors. Disturbance intensity had a negative effect on plant coverage, whereas it had a variable effect on species richness across plant growth forms. Plant coverage had a strong positive total effect on aboveground biomass (β = 0.84 for shrubs, 0.88 for forbs, and 0.85 for grasses), followed by a positive effect of species richness, and a negative effect of disturbance intensity across plant growth forms. Our results shed light on the management of rangelands that is high plant coverage can significantly improve species richness and aboveground biomass across plant growth forms. We also found that high disturbance intensity due to heavy grazing has a strong negative effect on plant coverage rather than species richness in semi-steppe rangelands. This study suggests that proper grazing systems (e.g. rotational system) based on carrying capacity and stocking rate of a rangeland may be helpful for biodiversity conservation, better grazing of livestock, improvement of plant coverage and enhancement of aboveground biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

Freeze or Flee? Negative Stimuli Elicit Selective Responding

ERIC Educational Resources Information Center

Estes, Zachary; Verges, Michelle

2008-01-01

Humans preferentially attend to negative stimuli. A consequence of this automatic vigilance for negative valence is that negative words elicit slower responses than neutral or positive words on a host of cognitive tasks. Some researchers have speculated that negative stimuli elicit a general suppression of motor activity, akin to the freezing…
What to eat in a warming world: do increased temperatures necessitate hazardous duty pay?

USGS Publications Warehouse

Hall, L. Embere; Chalfoun, Anna D.

2018-01-01

Contemporary climate change affects nearly all biomes, causing shifts in animal distributions and resource availability. Changes in resource selection may allow individuals to offset climatic stress, thereby providing a mechanism for persistence amidst warming conditions. Whereas the role of predation risk in food choice has been studied broadly, the extent to which individuals respond to thermoregulatory risk by changing resource preferences is unclear. We addressed whether individuals compensated for temperature-related reductions in foraging time by altering forage preferences, using the American pika (Ochotona princeps) as a model species. We tested two hypotheses: (1) food-quality hypothesis—individuals exposed to temperature extremes should select higher-quality vegetation in return for accepting a physiologically riskier feeding situation; and (2) food-availability hypothesis—individuals exposed to temperature extremes should prioritize foraging quickly, thereby decreasing selection for higher-quality food. We quantified the composition and quality (% moisture, % nitrogen, and fiber content) of available and harvested vegetation, and deployed a network of temperature sensors to measure in situ conditions for 30 individuals, during July–Sept., 2015. Individuals exposed to more extreme daytime temperatures showed increased selection for high-nitrogen and for low-fiber vegetation, demonstrating strong support for the food-quality hypothesis. By contrast, pikas that experienced warmer conditions did not reduce selection for any of the three vegetation-quality metrics, as predicted by the food-availability hypothesis. By shifting resource-selection patterns, temperature-limited animals may be able to proximately buffer some of the negative effects associated with rapidly warming environments, provided that sufficient resources remain on the landscape.
Improving the efficiency of feed utilization in poultry by selection. 1. Genetic parameters of anatomy of the gastro-intestinal tract and digestive efficiency.

PubMed

de Verdal, Hugues; Narcy, Agnès; Bastianelli, Denis; Chapuis, Hervé; Même, Nathalie; Urvoix, Séverine; Le Bihan-Duval, Elisabeth; Mignon-Grasteau, Sandrine

2011-07-06

Feed costs represent about 70% of the costs of raising broilers. The main way to decrease these costs is to improve feed efficiency by modification of diet formulation, but one other possibility would be to use genetic selection. Understanding the genetic architecture of the gastro-intestinal tract (GIT) and the impact of the selection criterion on the GIT would be of particular interest. We therefore studied the genetic parameters of AMEn (Apparent metabolisable energy corrected for zero nitrogen balance), feed efficiency, and GIT traits in chickens.Genetic parameters were estimated for 630 broiler chickens of the eighth generation of a divergent selection experiment on AMEn. Birds were reared until 23 d of age and fed a wheat-based diet. The traits measured were body weight (BW), feed conversion ratio (FCR), AMEn, weights of crop, liver, gizzard and proventriculus, and weight, length and density of the duodenum, jejunum and ileum. The heritability estimates of BW, FCR and AMEn were moderate. The heritability estimates were higher for the GIT characteristics except for the weights of the proventriculus and liver. Gizzard weight was negatively correlated with density (weight to length ratio) of duodenum, jejunum and ileum. Proventriculus and gizzard weights were more strongly correlated with AMEn than with FCR, which was not the case for intestine weight and density. GIT traits were largely dependent on genetics and that selecting on AMEn or FCR would modify them. Phenotypic observations carried out in the divergent lines selected on AMEn were consistent with estimated genetic correlations between AMEn and GIT traits.
Compensatory selection for roads over natural linear features by wolves in northern Ontario: Implications for caribou conservation

PubMed Central

Patterson, Brent R.; Anderson, Morgan L.; Rodgers, Arthur R.; Vander Vennen, Lucas M.; Fryxell, John M.

2017-01-01

Woodland caribou (Rangifer tarandus caribou) in Ontario are a threatened species that have experienced a substantial retraction of their historic range. Part of their decline has been attributed to increasing densities of anthropogenic linear features such as trails, roads, railways, and hydro lines. These features have been shown to increase the search efficiency and kill rate of wolves. However, it is unclear whether selection for anthropogenic linear features is additive or compensatory to selection for natural (water) linear features which may also be used for travel. We studied the selection of water and anthropogenic linear features by 52 resident wolves (Canis lupus x lycaon) over four years across three study areas in northern Ontario that varied in degrees of forestry activity and human disturbance. We used Euclidean distance-based resource selection functions (mixed-effects logistic regression) at the seasonal range scale with random coefficients for distance to water linear features, primary/secondary roads/railways, and hydro lines, and tertiary roads to estimate the strength of selection for each linear feature and for several habitat types, while accounting for availability of each feature. Next, we investigated the trade-off between selection for anthropogenic and water linear features. Wolves selected both anthropogenic and water linear features; selection for anthropogenic features was stronger than for water during the rendezvous season. Selection for anthropogenic linear features increased with increasing density of these features on the landscape, while selection for natural linear features declined, indicating compensatory selection of anthropogenic linear features. These results have implications for woodland caribou conservation. Prey encounter rates between wolves and caribou seem to be strongly influenced by increasing linear feature densities. This behavioral mechanism–a compensatory functional response to anthropogenic linear feature density resulting in decreased use of natural travel corridors–has negative consequences for the viability of woodland caribou. PMID:29117234
Compensatory selection for roads over natural linear features by wolves in northern Ontario: Implications for caribou conservation.

PubMed

Newton, Erica J; Patterson, Brent R; Anderson, Morgan L; Rodgers, Arthur R; Vander Vennen, Lucas M; Fryxell, John M

2017-01-01

Woodland caribou (Rangifer tarandus caribou) in Ontario are a threatened species that have experienced a substantial retraction of their historic range. Part of their decline has been attributed to increasing densities of anthropogenic linear features such as trails, roads, railways, and hydro lines. These features have been shown to increase the search efficiency and kill rate of wolves. However, it is unclear whether selection for anthropogenic linear features is additive or compensatory to selection for natural (water) linear features which may also be used for travel. We studied the selection of water and anthropogenic linear features by 52 resident wolves (Canis lupus x lycaon) over four years across three study areas in northern Ontario that varied in degrees of forestry activity and human disturbance. We used Euclidean distance-based resource selection functions (mixed-effects logistic regression) at the seasonal range scale with random coefficients for distance to water linear features, primary/secondary roads/railways, and hydro lines, and tertiary roads to estimate the strength of selection for each linear feature and for several habitat types, while accounting for availability of each feature. Next, we investigated the trade-off between selection for anthropogenic and water linear features. Wolves selected both anthropogenic and water linear features; selection for anthropogenic features was stronger than for water during the rendezvous season. Selection for anthropogenic linear features increased with increasing density of these features on the landscape, while selection for natural linear features declined, indicating compensatory selection of anthropogenic linear features. These results have implications for woodland caribou conservation. Prey encounter rates between wolves and caribou seem to be strongly influenced by increasing linear feature densities. This behavioral mechanism-a compensatory functional response to anthropogenic linear feature density resulting in decreased use of natural travel corridors-has negative consequences for the viability of woodland caribou.
The impact of selection bias on vaccine effectiveness estimates from test-negative studies.

PubMed

Jackson, Michael L; Phillips, C Hallie; Benoit, Joyce; Kiniry, Erika; Madziwa, Lawrence; Nelson, Jennifer C; Jackson, Lisa A

2018-01-29

Estimates of vaccine effectiveness (VE) from test-negative studies may be subject to selection bias. In the context of influenza VE, we used simulations to identify situations in which meaningful selection bias can occur. We also analyzed observational study data for evidence of selection bias. For the simulation study, we defined a hypothetical population whose members are at risk for acute respiratory illness (ARI) due to influenza and other pathogens. An unmeasured "healthcare seeking proclivity" affects both probability of vaccination and probability of seeking care for an ARI. We varied the direction and magnitude of these effects and identified situations where meaningful bias occurred. For the observational study, we reanalyzed data from the United States Influenza VE Network, an ongoing test-negative study. We compared "bias-naïve" VE estimates to bias-adjusted estimates, which used data from the source populations to correct for sampling bias. In the simulation study, an unmeasured care-seeking proclivity could create selection bias if persons with influenza ARI were more (or less) likely to seek care than persons with non-influenza ARI. However, selection bias was only meaningful when rates of care seeking between influenza ARI and non-influenza ARI were very different. In the observational study, the bias-naïve VE estimate of 55% (95% CI, 47--62%) was trivially different from the bias-adjusted VE estimate of 57% (95% CI, 49--63%). In combination, these studies suggest that while selection bias is possible in test-negative VE studies, this bias in unlikely to be meaningful under conditions likely to be encountered in practice. Researchers and public health officials can continue to rely on VE estimates from test-negative studies. Copyright © 2017 Elsevier Ltd. All rights reserved.
Meta-analysis of age and skill effects on recalling chess positions and selecting the best move.

PubMed

Moxley, Jerad H; Charness, Neil

2013-10-01

A meta-analysis was conducted of studies that measured the effects of both age and skill in chess on the tasks of selecting the best move for chess positions (the best move task) as well as recalling chess game positions (the recall task). Despite a small sample of studies, we demonstrated that there are age and skill effects on both tasks: age being negatively associated with performance on both tasks and skill being positively associated with performance on both tasks. On the best move task, we found that skill was the dominant effect, while on the recall task, skill and age were approximately equally strong effects. We also found that skill was best measured by the best move task. In the case of the best move task, this result is consistent with the argument that it accurately replicates expert performance (Ericsson & Smith, 1991). Results for the recall task argue that this task captures effects related to skill, but also effects likely due to a general aging process. Implications for our understanding of aging in skilled domains are also discussed.
Detection of Listeria monocytogenes in pork and beef using the VIDAS® LMO2 automated enzyme linked immunoassay method.

PubMed

Meyer, Cornelia; Fredriksson-Ahomaa, Maria; Sperner, Brigitte; Märtlbauer, Erwin

2011-07-01

Listeria (L.) monocytogenes, a foodborne pathogen, is known to be a possible contaminant of foods during production and processing. Samples (n=985) of raw meat and by-products obtained from beef and pork were first screened by the VIDAS system for the presence of Listeria spp., followed by testing for the presence of L. monocytogenes. Positive L. monocytogenes results were confirmed by plating on selective agars: 14% of the samples were positive for Listeria and 4% tested positive for L. monocytogenes, of which 3% were confirmed on selective agars. In by-products (17%) the contamination with listeriae was higher than in meat cuts (10%). Only samples strongly positive for Listeria spp. by VIDAS were positive for L. monocytogenes. Overall, the prevalence of L. monocytogenes in beef and pork samples was rather low in comparison to most previous studies. The VIDAS system was shown to be a suitable method for screening out Listeria-negative samples; the main advantage being a markedly reduced assay time. Copyright © 2011 Elsevier Ltd. All rights reserved.
Targeted Sos1 deletion reveals its critical role in early T-cell development

PubMed Central

Kortum, Robert L.; Sommers, Connie L.; Alexander, Clayton P.; Pinski, John M.; Li, Wenmei; Grinberg, Alex; Lee, Jan; Love, Paul E.; Samelson, Lawrence E.

2011-01-01

Activation of the small G protein Ras is required for thymocyte differentiation. In thymocytes, Ras is activated by the Ras guanine exchange factors (RasGEFs) Sos1, Sos2, and RasGRP1. We report the development of a floxed allele of sos1 to assess the role of Sos1 during thymocyte development. Sos1 was required for pre–T-cell receptor (pre-TCR)– but not TCR-stimulated developmental signals. Sos1 deletion led to a partial block at the DN-to-DP transition. Sos1-deficient thymocytes showed reduced pre-TCR–stimulated proliferation, differentiation, and ERK phosphorylation. In contrast, TCR-stimulated positive selection, and negative selection under strong stimulatory conditions, remained intact in Sos1-deficient mice. Comparison of RasGEF expression at different developmental stages showed that relative to Sos2 and RasGRP1, Sos1 is most abundant in DN thymocytes, but least abundant in DP thymocytes. These data reveal that Sos1 is uniquely positioned to affect signal transduction early in thymocyte development. PMID:21746917
Relationship Among Dental Students' Class Lecture Attendance, Use of Online Resources, and Performance.

PubMed

Azab, Ehab; Saksena, Yun; Alghanem, Tofool; Midle, Jennifer Bassett; Molgaard, Kathleen; Albright, Susan; Karimbux, Nadeem

2016-04-01

This study aimed to evaluate the relationship among dental students' attendance at class lectures, use of online lecture materials, and performance in didactic courses. The study was conducted with second-year predoctoral students at Tufts University School of Dental Medicine during the fall semester of 2014. Three basic science and three preclinical dental courses were selected for evaluation. Online usage for each participant was collected, and a survey with questions about attendance and online behavior was conducted. The final grade for each participant in each selected course was obtained and matched with his or her online usage and attendance. Out of a total 190 students, 146 (77%) participated. The results showed no significant relationship between students' grades and their class attendance or online usage except for a weak negative relationship between class attendance and online usage for the Epidemiology course (p<0.001) and the overall preclinical dental courses (p=0.03). Although the results did not show strong relationships among class attendance, online usage, and course grades, most of the students reported that having the online resources in addition to the lectures was helpful.
'You are inferior!' Revisiting the expressivist argument.

PubMed

Hofmann, Bjørn

2017-09-01

According to the expressivist argument the choice to use biotechnologies to prevent the birth of individuals with specific disabilities is an expression of disvalue for existing people with this disability. The argument has stirred a lively debate and has recently received renewed attention. This article starts with presenting the expressivist argument and its core elements. It then goes on to present and examine the counter-arguments before it addresses some aspects that have gained surprisingly little attention. The analysis demonstrates that the expressivist argument has a wide range of underpinnings and that counter-arguments tend to focus on only a few of these. It also reveals an important aspect that appears to have been ignored, i.e., that people do not select foetuses based on chromosomes or other biological traits, but based on characteristics of living persons with specific disabilities. This makes it more difficult to undermine the claim that negative selection of foetuses expresses a disvaluing of persons with such disabilities. It leaves the expressivist argument with a strong bite still. © 2017 John Wiley & Sons Ltd.
Promiscuity resolves constraints on social mate choice imposed by population viscosity.

PubMed

While, Geoffrey M; Uller, Tobias; Bordogna, Genevieve; Wapstra, Erik

2014-02-01

Population viscosity can have major consequences for adaptive evolution, in particular for phenotypes involved in social interactions. For example, population viscosity increases the probability of mating with close kin, resulting in selection for mechanisms that circumvent the potential negative consequences of inbreeding. Female promiscuity is often suggested to be one such mechanism. However, whether avoidance of genetically similar partners is a major selective force shaping patterns of promiscuity remains poorly supported by empirical data. Here, we show (i) that fine-scale genetic structure constrains social mate choice in a pair-bonding lizard, resulting in individuals pairing with genetically similar individuals, (ii) that these constraints are circumvented by multiple mating with less related individuals and (iii) that this results in increased heterozygosity of offspring. Despite this, we did not detect any significant effects of heterozygosity on offspring or adult fitness or a strong relationship between pair relatedness and female multiple mating. We discuss these results within the context of incorporating the genetic context dependence of mating strategies into a holistic understanding of mating system evolution. © 2013 John Wiley & Sons Ltd.
IQ AND SOCIOECONOMIC DEVELOPMENT ACROSS REGIONS OF THE UK.

PubMed

Carl, Noah

2016-05-01

Cross-regional correlations between average IQ and socioeconomic development have been documented in many different countries. This paper presents new IQ estimates for the twelve regions of the UK. These are weakly correlated (r=0.24) with the regional IQs assembled by Lynn (1979). Assuming the two sets of estimates are accurate and comparable, this finding suggests that the relative IQs of different UK regions have changed since the 1950s, most likely due to differentials in the magnitude of the Flynn effect, the selectivity of external migration, the selectivity of internal migration or the strength of the relationship between IQ and fertility. The paper provides evidence for the validity of the regional IQs by showing that IQ estimates for UK nations (England, Scotland, Wales and Northern Ireland) derived from the same data are strongly correlated with national PISA scores (r=0.99). It finds that regional IQ is positively related to income, longevity and technological accomplishment; and is negatively related to poverty, deprivation and unemployment. A general factor of socioeconomic development is correlated with regional IQ at r=0.72.
Development of a small-molecule screening method for inhibitors of cellular response to myostatin and activin A.

PubMed

Cash, Jennifer N; Angerman, Elizabeth B; Kirby, R Jason; Merck, Lisa; Seibel, William L; Wortman, Matthew D; Papoian, Ruben; Nelson, Sandra; Thompson, Thomas B

2013-08-01

Myostatin, a member of the transforming growth factor (TGF)-β family of secreted ligands, is a strong negative regulator of muscle growth. As such, therapeutic inhibitors of myostatin are actively being investigated for their potential in the treatment of muscle-wasting diseases such as muscular dystrophy and sarcopenia. Here, we sought to develop a high-throughput screening (HTS) method for small-molecule inhibitors that target myostatin. We created a HEK293 stable cell line that expresses the (CAGA)12-luciferase reporter construct and robustly responds to signaling of certain classes of TGF-β family ligands. After optimization and miniaturization of the assay to a 384-well format, we successfully screened a library of compounds for inhibition of myostatin and the closely related activin A. Selection of some of the tested compounds was directed by in silico screening against myostatin, which led to an enrichment of target hits as compared with random selection. Altogether, we present an HTS method that will be useful for screening potential inhibitors of not only myostatin but also many other ligands of the TGF-β family.
Napping and the Selective Consolidation of Negative Aspects of Scenes

PubMed Central

Payne, Jessica D.; Kensinger, Elizabeth A.; Wamsley, Erin; Spreng, R. Nathan; Alger, Sara; Gibler, Kyle; Schacter, Daniel L.; Stickgold, Robert

2018-01-01

After information is encoded into memory, it undergoes an offline period of consolidation that occurs optimally during sleep. The consolidation process not only solidifies memories, but also selectively preserves aspects of experience that are emotionally salient and relevant for future use. Here, we provide evidence that an afternoon nap is sufficient to trigger preferential memory for emotional information contained in complex scenes. Selective memory for negative emotional information was enhanced after a nap compared to wakefulness in two control conditions designed to carefully address interference and time-of-day confounds. Although prior evidence has connected negative emotional memory formation to rapid eye movement (REM) sleep physiology, we found that non-REM delta activity and the amount of slow wave sleep (SWS) in the nap were robustly related to the selective consolidation of negative information. These findings suggest that the mechanisms underlying memory consolidation benefits associated with napping and nighttime sleep are not always the same. Finally, we provide preliminary evidence that the magnitude of the emotional memory benefit conferred by sleep is equivalent following a nap and a full night of sleep, suggesting that selective emotional remembering can be economically achieved by taking a nap. PMID:25706830
Heat amplification and negative differential thermal conductance in a strongly coupled nonequilibrium spin-boson system

NASA Astrophysics Data System (ADS)

Wang, Chen; Chen, Xu-Min; Sun, Ke-Wei; Ren, Jie

2018-05-01

We investigate the nonequilibrium quantum heat transfer in a quantum thermal transistor, constructed by a triangle-coupled spin-boson system in a three-terminal setup. By exploiting the nonequilibrium noninteracting blip approximation approach combined with full counting statistics, we obtain the steady-state thermal transport, such as heat currents. We identify the giant heat amplification feature in a strong coupling regime, which results from the negative differential thermal conductance with respect to the gate temperature. Analysis shows that the strong coupling between the gate qubit and corresponding gate thermal bath plays the crucial role in exhibiting these far-from-equilibrium features. These results would have potential implications in designing efficient quantum thermal transistors in the future.
A novel local anti-colorectal cancer drug delivery system: negative lipidoid nanoparticles with a passive target via a size-dependent pattern

NASA Astrophysics Data System (ADS)

Ding, Weifeng; Wang, Feng; Zhang, Jianfeng; Guo, Yibing; Ju, Shaoqing; Wang, Huimin

2013-09-01

The nontoxic, targeted and effective delivery of nucleic acid drugs remains an important challenge for clinical development. Here, we describe a novel negative lipidoid nanoparticle delivery system, providing entrapment-based transfection agents for local delivery of siRNA to the colorectal cancer focus. The delivery system was synthesized with lipidoid material 98N12-5(1), mPEG2000-C12/C14 glyceride and cholesterol at a desired molar ratio to realize the anionic surface charge of particles, which could alleviate to a larger degree the inflammatory response and immune stimulation of the organism, embodying dramatic biocompatibility. In particular, mPEG2000-C12/C14 glyceride was selected to ameliorate the stability of the delivery system and protection of nucleic acids by extending the tail length of the carbons, crucial also to neutralize the positive charge of 98N12-5(1) to form a resultant anionic particle. In vivo experiments revealed that a particle size of 90 nm perfectly realized a passive target in a size-dependent manner and did not affect the function of the liver and kidneys by a local delivery method, enema. We clarified that the uptake of negative lipidoid nanoparticles internalized through a lipid raft endocytotic pathway with low cytotoxicity, strong biocompatibility and high efficacy. This study suggests that negative lipidoid nanoparticles with enema delivery costitute, uniquely and appropriately, a local anti-colorectal cancer nucleic acid drug delivery platform, and the application of similar modes may be feasible in other therapeutic settings.
Comparison of amine-selective properties of weak and strong cation-exchangers.

PubMed

Stenholm, Ake; Lindgren, Helena; Shaffie, Juliana

2006-09-22

The capacity of several weak and strong cation-exchangers to adsorb 2-diethylaminoethanol (DEAE) and (2,3-hydroxypropyl) trimethylammonium chloride (HPMAC) from sodium-containing process water streams, and the ease of subsequently eluting the amines and regenerating the exchangers, were investigated. (2,3-hydroxypropyl) trimethylammonium chloride was enriched 40-fold compared with the initial amine/sodium-ratio in the bulk fluid by Amberlite IRC-50. The highest selectivity for 2-diethylaminoethanol (26-fold) was provided by Imac HP336. Neither of the selected strong cation-exchangers showed any selectivity towards 2-diethylaminoethanol, but they enriched (2,3-hydroxypropyl) trimethylammonium chloride approximately three to four fold. These findings suggest that weak cation-exchangers (WCX) could be readily used for the selective removal of these or similar amines from sodium-containing process waters.
Is There a Paradox of Aging: When the Negative Aging Stereotype Meets the Positivity Effect in Older Adults.

PubMed

Zhou, Liqing; Lu, Jia; Chen, Guopeng; Dong, Li; Yao, Yujia

2017-01-01

Background/Study Context: Socioemotional selectivity theory (SST) states that the positivity effect is a result of older adults' emotion regulation and that older adults derive more emotional satisfaction from prioritizing positive information processing. The authors explored whether the positivity effect appeared when the negative aging stereotype was activated in older adults and also whether the effect differed between mixed and unmixed valence conditions. Sixty younger (18-23 years of age) and 60 older (60-87 years of age) adults were randomly assigned to a control group and a priming group, in which the negative aging stereotype was activated. All the participants were asked to select 15 words that best described the elderly from a mixed-word list (positive and negative words were mixed together) and from an unmixed-word list (positive and negative words were separated). Older adults in the control group selected more positive words, whereas among younger adults, selection did not differ by valence in either the mixed- or unmixed-word list conditions. There were no differences between the positive and negative word choices of the younger and older adults in the priming group. We calculated the differences between the numbers of positive and negative words, and the differences in the older adults' word choices were larger than those among the younger adults; the differences were also larger in the control group than in the priming group. The positivity effect worked by choosing positive stimuli rather than avoiding negative stimuli. The role of emotion regulation in older adults was limited, and when the positivity effect faced the effect of the negative aging stereotype, the negative stereotype effect was dominant. Future research should explore the changes in the positivity effect in the face of a positive aging stereotype and what roles other factors (e.g., activation level of the stereotype, arousal level of affective words) might play.
Strong Purifying Selection at Synonymous Sites in D. melanogaster

PubMed Central

Lawrie, David S.; Messer, Philipp W.; Hershberg, Ruth; Petrov, Dmitri A.

2013-01-01

Synonymous sites are generally assumed to be subject to weak selective constraint. For this reason, they are often neglected as a possible source of important functional variation. We use site frequency spectra from deep population sequencing data to show that, contrary to this expectation, 22% of four-fold synonymous (4D) sites in Drosophila melanogaster evolve under very strong selective constraint while few, if any, appear to be under weak constraint. Linking polymorphism with divergence data, we further find that the fraction of synonymous sites exposed to strong purifying selection is higher for those positions that show slower evolution on the Drosophila phylogeny. The function underlying the inferred strong constraint appears to be separate from splicing enhancers, nucleosome positioning, and the translational optimization generating canonical codon bias. The fraction of synonymous sites under strong constraint within a gene correlates well with gene expression, particularly in the mid-late embryo, pupae, and adult developmental stages. Genes enriched in strongly constrained synonymous sites tend to be particularly functionally important and are often involved in key developmental pathways. Given that the observed widespread constraint acting on synonymous sites is likely not limited to Drosophila, the role of synonymous sites in genetic disease and adaptation should be reevaluated. PMID:23737754

MR Enterography of the Ileoanal Pouch: Descriptive Radiologic Analysis With Endoscopic and Pathologic Correlation.

PubMed

Sahi, Kamaldeep Singh; Lee, Karen S; Moss, Alan; Yee, Eric; Allard, Felicia; Brook, Alexander; Mortele, Koenraad J

2015-11-01

The purpose of this study was to describe the MR enterography (MRE) appearance of inflammation of the ileoanal pouch after ileal pouch-anal anastomosis (IPAA) surgery and to correlate it with pouch endoscopic and histopathologic findings. All MRE studies performed between October 1, 2007, and September 30, 2013, for patients who had previously undergone IPAA (n = 54) were retrieved. After review of medical records, the patients who underwent MRE, pouch endoscopy, and biopsy within 90 days (14 men, 14 women; mean age, 42.2 years; range, 24-67 years) were selected for inclusion in the study. Two blinded MRI radiologists in consensus retrospectively evaluated MRE studies for multiple MRI features. Two MRI scores were then calculated: an active and a composite inflammation score. A gastroenterologist retrospectively reviewed the pouch endoscopic images, and a pathologist reviewed the slides; both of these investigators were blinded. Both MRI scores were correlated with the pouch endoscopic and histopathologic findings. The composite MRI score had strong positive correlation with the endoscopic score (r = 0.61; p = 0.0005) but weak positive correlation with the histopathologic score (r = 0.31; p = 0.10, not statistically significant). The active inflammation MRI score had moderate positive correlation with the endoscopic score (r = 0.57; p = 0.0017) and weak positive correlation with the histopathologic score (r = 0.20; p = 0.31, not statistically significant). An MRI score ≥ 4 indicated the best results, with sensitivity of 86%, specificity of 79%, positive predictive value of 80%, negative predictive value of 85%, and accuracy of 82% for pouch inflammation. A positive likelihood ratio of 4.00 and negative likelihood ratio of 0.18 were obtained. In patients who have undergone IPAA surgery, the MRE findings strongly correlate with the pouch endoscopic findings with high sensitivity and positive predictive value for pouch inflammation. Therefore, MRE is a useful noninvasive test performed without ionizing radiation that can be used to evaluate patients with clinical symptoms and possibly alleviate the need for endoscopy in a select patient population.
Channel architecture in maltoporin: dominance studies with lamB mutations influencing maltodextrin binding provide evidence for independent selectivity filters in each subunit.

PubMed Central

Ferenci, T; Lee, K S

1989-01-01

Maltoporin trimers constitute maltodextrin-selective channels in the outer membrane of Escherichia coli. To study the organization of the maltodextrin-binding site within trimers, dominance studies were undertaken with maltoporin variants of altered binding affinity. It has been established that amino acid substitutions at three dispersed regions of the maltoporin sequence (at residues 8, 82, and 360) resulted specifically in maltodextrin-binding defects and loss of maltodextrin channel selectivity; a substitution at residue 118 increased both binding affinity and maltodextrin transport. Strains heterodiploid for lamB were constructed in which these substitutions were encoded by chromosomal and plasmid-borne genes, and the relative level of maltoporin expression from these genes was estimated. Binding assays with bacteria forming maltoporin heterotrimers were performed in order to test for complementation between binding-negative alleles, negative dominance of negative over wild-type alleles, and possible dominance of negatives over the high-affinity allele. Double mutants with mutations affecting residues 8 and 118, 82 and 118, and 118 and 360 were constructed in vitro, and the dominance properties of the mutations in cis were also tested. There was no complementation between negatives and no negative dominance in heterotrimers. The high-affinity mutation was dominant over negatives in trans but not in cis. The affinity of binding sites in heterotrimer populations was characteristic of the high-affinity allele present and uninfluenced by the negative allele. These results are consistent with the presence of three discrete binding sites in a maltoporin trimer and suggest that the selectivity filter for maltodextrins is not at the interface between the three subunits. PMID:2521623
NegGOA: negative GO annotations selection using ontology structure.

PubMed

Fu, Guangyuan; Wang, Jun; Yang, Bo; Yu, Guoxian

2016-10-01

Predicting the biological functions of proteins is one of the key challenges in the post-genomic era. Computational models have demonstrated the utility of applying machine learning methods to predict protein function. Most prediction methods explicitly require a set of negative examples-proteins that are known not carrying out a particular function. However, Gene Ontology (GO) almost always only provides the knowledge that proteins carry out a particular function, and functional annotations of proteins are incomplete. GO structurally organizes more than tens of thousands GO terms and a protein is annotated with several (or dozens) of these terms. For these reasons, the negative examples of a protein can greatly help distinguishing true positive examples of the protein from such a large candidate GO space. In this paper, we present a novel approach (called NegGOA) to select negative examples. Specifically, NegGOA takes advantage of the ontology structure, available annotations and potentiality of additional annotations of a protein to choose negative examples of the protein. We compare NegGOA with other negative examples selection algorithms and find that NegGOA produces much fewer false negatives than them. We incorporate the selected negative examples into an efficient function prediction model to predict the functions of proteins in Yeast, Human, Mouse and Fly. NegGOA also demonstrates improved accuracy than these comparing algorithms across various evaluation metrics. In addition, NegGOA is less suffered from incomplete annotations of proteins than these comparing methods. The Matlab and R codes are available at https://sites.google.com/site/guoxian85/neggoa gxyu@swu.edu.cn Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
Highly Selective Coupling of Alkenes and Aldehydes Catalyzed by NHC–Ni–P(OPh)3: Synergy Between a Strong σ-Donor and a Strong π-Acceptor**

PubMed Central

Ho, Chun-Yu; Jamison, Timothy F.

2011-01-01

Both a strong electron donor (IPr) and a strong electron acceptor (P(OPh)3) are necessary for a highly selective, nickel-catalyzed coupling reaction between alkenes, aldehydes, and silyltriflates. Without the phosphite, catalysis is not observed and several side reactions are observed. The phosphite appears to suppress the formation of these byproducts and rescue the catalytic cycle by accelerating reductive elimination from an (IPr–Ni–H)(OTf) complex. PMID:17154217
Fitness cost of incubation in great tits (Parus major) is related to clutch size

PubMed Central

de Heij, Maaike E; van den Hout, Piet J; Tinbergen, Joost M

2006-01-01

Life-history theory predicts that parents produce the number of offspring that maximizes their fitness. In birds, natural selection on parental decisions regarding clutch size may act during egg laying, incubation or nestling phase. To study the fitness consequences of clutch size during the incubation phase, we manipulated the clutch sizes during this phase only in three breeding seasons and measured the fitness consequences on the short and the long term. Clutch enlargement did not affect the offspring fitness of the manipulated first clutches, but fledging probability of the subsequent clutch in the same season was reduced. Parents incubating enlarged first clutches provided adequate care for the offspring of their first clutches during the nestling phase, but paid the price when caring for the offspring of their second clutch. Parents that incubated enlarged first clutches had lower local survival in the 2 years when the population had a relatively high production of second clutches, but not in the third year when there was a very low production of second clutches. During these 2 years, the costs of incubation were strong enough to change positive selection, as established by brood size manipulations in this study population, into stabilizing selection through the negative effect of incubation on parental fitness. PMID:16928638
Larva-mediated chalkbrood resistance-associated single nucleotide polymorphism markers in the honey bee Apis mellifera.

PubMed

Liu, Y; Yan, L; Li, Z; Huang, W-F; Pokhrel, S; Liu, X; Su, S

2016-06-01

Chalkbrood is a disease affecting honey bees that seriously impairs brood growth and productivity of diseased colonies. Although honey bees can develop chalkbrood resistance naturally, the details underlying the mechanisms of resistance are not fully understood, and no easy method is currently available for selecting and breeding resistant bees. Finding the genes involved in the development of resistance and identifying single nucleotide polymorphisms (SNPs) that can be used as molecular markers of resistance is therefore a high priority. We conducted genome resequencing to compare resistant (Res) and susceptible (Sus) larvae that were selected following in vitro chalkbrood inoculation. Twelve genomic libraries, including 14.4 Gb of sequence data, were analysed using SNP-finding algorithms. Unique SNPs derived from chromosomes 2 and 11 were analysed in this study. SNPs from resistant individuals were confirmed by PCR and Sanger sequencing using in vitro reared larvae and resistant colonies. We found strong support for an association between the C allele at SNP C2587245T and chalkbrood resistance. SNP C2587245T may be useful as a genetic marker for the selection of chalkbrood resistance and high royal jelly production honey bee lines, thereby helping to minimize the negative effects of chalkbrood on managed honey bees. © 2016 The Royal Entomological Society.
Influences on the decision to study veterinary medicine: variation with sex and background.

PubMed

Tomlin, J L; Brodbelt, D C; May, S A

2010-06-12

A questionnaire was developed to look at attitudes to veterinary medicine as a career choice among students at different stages of the veterinary course at the Royal Veterinary College. Traditional-entry first-year and final-year students, as well as entry-level 'Gateway' (widening participation) students, were invited to participate. Wanting to work with animals and exposure to a veterinary role model through taking a sick animal to visit a veterinary surgeon appeared to be major factors in choosing a veterinary career for all undergraduates, regardless of their socioeconomic background. Overall, women were more strongly influenced by owning animals (P=0.014), and men were more positively influenced by the challenging reputation of the course (P=0.028). When the students were asked to indicate their top three reasons for wanting to become a vet, men were 9.5 times as likely as women to select 'Want to train as a scientist', 5.3 times as likely to select 'Join a profession' and 13.2 times as likely to select 'Hardest course to get in to'; the top choice for both sexes was 'Want to work with animals'. Thirty-one per cent of the students felt their careers adviser had been a negative influence on their decision to become a vet.
By their words ye shall know them: Evidence of genetic selection against general intelligence and concurrent environmental enrichment in vocabulary usage since the mid 19th century

PubMed Central

Menie, Michael A. Woodley of; Fernandes, Heitor B. F.; José Figueredo, Aurelio; Meisenberg, Gerhard

2015-01-01

It has been theorized that declines in general intelligence (g) due to genetic selection stemming from the inverse association between completed fertility and IQ and the Flynn effect co-occur, with the effects of the latter being concentrated on less heritable non-g sources of intelligence variance. Evidence for this comes from the observation that 19th century populations were more intellectually productive, and also exhibited faster simple reaction times than modern ones, suggesting greater information-processing ability and therefore higher g. This co-occurrence model is tested via examination of historical changes in the utilization frequencies of words from the highly g-loaded WORDSUM test across 5.9 million texts spanning the period 1850–2005. Consistent with predictions, words with higher difficulties (δ parameters from Item Response Theory) and stronger negative correlations between pass rates and completed fertility declined in use over time whereas less difficult and less strongly selected words, increased in use over time, consistent with a Flynn effect stemming in part from the vocabulary enriching effects of increases in population literacy. These findings persisted when explicitly controlled for word age, changing literacy rates and temporal autocorrelation. These trends constitute compelling evidence for the co-occurrence model. PMID:25954211
Material deprivation or minimal education? Social class and crime in an egalitarian welfare state.

PubMed

Savolainen, Jukka; Paananen, Reija; Merikukka, Marko; Aaltonen, Mikko; Gissler, Mika

2013-09-01

Research on social class and crime is dominated by perspectives that assume socioeconomic disadvantage to exert causal influence on offending. As an alternative approach, the present study examined hypotheses derived from a social selection perspective which treats intergenerational continuity in antisocial propensity as the primary source of socioeconomic differences in criminal activity. Under this theory, individual characteristics of the parents influence their personal socioeconomic attainment as well as the behavioral traits they pass on to their children. Consistent with both of these perspectives, longitudinal data tracking Finnish males born in 1987 (n=21,513) showed strong negative associations between family socioeconomic status (SES) and offspring rates of criminal offending. In critical support for the selection perspective: (1) these association were linear rather than discrete, (2) parents' educational attainment accounted for most of the association between the occupational measure of family SES and crime, and (3) measures of offspring criminal propensity mediated a substantial share of these effects. Adolescent educational marginalization emerged as the key factor linking childhood socioeconomic status to the risk of criminal offending in emerging adulthood. We discuss the implications of this finding for social influence and social selection models of explanation. Copyright © 2013 Elsevier Ltd. All rights reserved.
Behavioral and neuronal determinants of negative reciprocity in the ultimatum game

PubMed Central

Hildebrandt, Andrea; Wilhelm, Oliver; Sommer, Werner

2016-01-01

The rejection of unfair offers in the ultimatum game (UG) indicates negative reciprocity. The model of strong reciprocity claims that negative reciprocity reflects prosociality because the rejecting individual is sacrificing resources in order to punish unfair behavior. However, a recent study found that the rejection rate of unfair offers is linked to assertiveness (status defense model). To pursue the question what drives negative reciprocity, the present study investigated individual differences in the rejection of unfair offers along with their behavioral and neuronal determinants. We measured fairness preferences and event-related potentials (ERP) in 200 healthy participants playing a computerized version of the UG with pictures of unfair and fair proposers. Structural equation modeling (SEM) on the behavioral data corroborated both the strong reciprocity and the status defense models of human cooperation: Not only more prosocial but also more assertive individuals were more likely to show negative reciprocity by rejecting unfair offers. Experimental ERP results confirmed the feedback negativity (FN) as a neural signature of fairness processing. Multilevel SEM of brain–behavior relationships revealed that negative reciprocity was significantly associated with individual differences in FN amplitudes in response to proposers. Our results confirm stable individual differences in fairness processing at the behavioral and neuronal level. PMID:27261490
The spiral of distrust: (Non-)cooperation in a repeated trust game is predicted by anger and individual differences in negative reciprocity orientation.

PubMed

Harth, Nicole S; Regner, Tobias

2017-12-01

This study investigated state anger and individual differences in negative reciprocity orientation as predictors of individuals' willingness to cooperate with strangers. In order to observe real behaviour, we used a trust game that was played over six periods. In the trust game, a first player (sender) determines how much of a certain endowment she/he wants to share with a second player (trustee), who then can give something back. We varied whether participants received feedback [feedback (yes, no)] about the trustee's behavioural decision (amount sent back). Supporting our hypotheses, the results suggest that feedback compared with no feedback about the trustee's behaviour increased anger. Specifically, information about low back transfers triggered anger and non-cooperation in return. Importantly, participants with a strong negative reciprocity orientation reported higher levels of anger and were less willing to cooperate with the trustee compared with those with low negative reciprocity orientation. Moreover, even when anger was low, individuals with a strong negative reciprocity orientation were less willing to cooperate compared with those with a low negative reciprocity orientation. Thus, negative reciprocity orientation seems to arouse a spiral of distrust. Theoretical and practical implications of these findings are discussed. © 2016 International Union of Psychological Science.
Climate variability slows evolutionary responses of Colias butterflies to recent climate change.

PubMed

Kingsolver, Joel G; Buckley, Lauren B

2015-03-07

How does recent climate warming and climate variability alter fitness, phenotypic selection and evolution in natural populations? We combine biophysical, demographic and evolutionary models with recent climate data to address this question for the subalpine and alpine butterfly, Colias meadii, in the southern Rocky Mountains. We focus on predicting patterns of selection and evolution for a key thermoregulatory trait, melanin (solar absorptivity) on the posterior ventral hindwings, which affects patterns of body temperature, flight activity, adult and egg survival, and reproductive success in Colias. Both mean annual summer temperatures and thermal variability within summers have increased during the past 60 years at subalpine and alpine sites. At the subalpine site, predicted directional selection on wing absorptivity has shifted from generally positive (favouring increased wing melanin) to generally negative during the past 60 years, but there is substantial variation among years in the predicted magnitude and direction of selection and the optimal absorptivity. The predicted magnitude of directional selection at the alpine site declined during the past 60 years and varies substantially among years, but selection has generally been positive at this site. Predicted evolutionary responses to mean climate warming at the subalpine site since 1980 is small, because of the variability in selection and asymmetry of the fitness function. At both sites, the predicted effects of adaptive evolution on mean population fitness are much smaller than the fluctuations in mean fitness due to climate variability among years. Our analyses suggest that variation in climate within and among years may strongly limit evolutionary responses of ectotherms to mean climate warming in these habitats. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
The post-pollination ethylene burst and the continuation of floral advertisement are harbingers of non-random mate selection in Nicotiana attenuata.

PubMed

Bhattacharya, Samik; Baldwin, Ian T

2012-08-01

The self-compatible plant Nicotiana attenuata grows in genetically diverse populations after fires, and produces flowers that remain open for 3 days and are visited by assorted pollinators. To determine whether and when post-pollination non-random mate selection occurs among self and non-self pollen, seed paternity and semi-in vivo pollen tube growth were determined in controlled single/mixed pollinations. Despite all pollen sources being equally proficient in siring seeds in single-genotype pollinations, self pollen was consistently selected in mixed pollinations, irrespective of maternal genotype. However, clear patterns of mate discrimination occurred amongst non-self pollen when mixed pollinations were performed soon after corollas open, including selection against hygromycin B resistance (transformation selectable marker) in wild-type styles and for it in transformed styles. However, mate choice among pollen genotypes was completely shut down in plants transformed to be unable to produce (irACO) or perceive (ETR1) ethylene. The post-pollination ethylene burst, which originates primarily from the stigma and upper style, was strongly correlated with mate selection in single and mixed hand-pollinations using eight pollen donors in two maternal ecotypes. The post-pollination ethylene burst was also negatively correlated with the continuation of emission of benzylacetone, the most abundant pollinator-attracting corolla-derived floral volatile. We conclude that ethylene signaling plays a pivotal role in mate choice, and the post-pollination ethylene burst and the termination of benzylacetone release are accurate predictors, both qualitatively and quantitatively, of pre-zygotic mate selection and seed paternity. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.
Sample Selection for Training Cascade Detectors.

PubMed

Vállez, Noelia; Deniz, Oscar; Bueno, Gloria

2015-01-01

Automatic detection systems usually require large and representative training datasets in order to obtain good detection and false positive rates. Training datasets are such that the positive set has few samples and/or the negative set should represent anything except the object of interest. In this respect, the negative set typically contains orders of magnitude more images than the positive set. However, imbalanced training databases lead to biased classifiers. In this paper, we focus our attention on a negative sample selection method to properly balance the training data for cascade detectors. The method is based on the selection of the most informative false positive samples generated in one stage to feed the next stage. The results show that the proposed cascade detector with sample selection obtains on average better partial AUC and smaller standard deviation than the other compared cascade detectors.
Integrating Negative Affect Measures in a Measurement Model: Assessing the Function of Negative Affect as Interference to Self-Regulation

ERIC Educational Resources Information Center

Magno, Carlo

2010-01-01

The present study investigated the composition of negative affect and its function as inhibitory to thought processes such as self-regulation. Negative affect in the present study were composed of anxiety, worry, thought suppression, and fear of negative evaluation. These four factors were selected based on the criteria of negative affect by…
A novel one-class SVM based negative data sampling method for reconstructing proteome-wide HTLV-human protein interaction networks.

PubMed

Mei, Suyu; Zhu, Hao

2015-01-26

Protein-protein interaction (PPI) prediction is generally treated as a problem of binary classification wherein negative data sampling is still an open problem to be addressed. The commonly used random sampling is prone to yield less representative negative data with considerable false negatives. Meanwhile rational constraints are seldom exerted on model selection to reduce the risk of false positive predictions for most of the existing computational methods. In this work, we propose a novel negative data sampling method based on one-class SVM (support vector machine, SVM) to predict proteome-wide protein interactions between HTLV retrovirus and Homo sapiens, wherein one-class SVM is used to choose reliable and representative negative data, and two-class SVM is used to yield proteome-wide outcomes as predictive feedback for rational model selection. Computational results suggest that one-class SVM is more suited to be used as negative data sampling method than two-class PPI predictor, and the predictive feedback constrained model selection helps to yield a rational predictive model that reduces the risk of false positive predictions. Some predictions have been validated by the recent literature. Lastly, gene ontology based clustering of the predicted PPI networks is conducted to provide valuable cues for the pathogenesis of HTLV retrovirus.
Negative refraction with low absorption using Raman transitions with magnetoelectric coupling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sikes, D. E.; Yavuz, D. D.

2010-07-15

We suggest a scheme for obtaining negative refraction that does not require the simultaneous presence of an electric-dipole and a magnetic-dipole transition near the same transition frequency. The key idea of the scheme is to obtain a strong electric response by using far-off-resonant Raman transitions. We propose to use a pair of electric-dipole Raman transitions and utilize magneto-electric cross coupling to achieve a negative index of refraction without requiring negative permeability. The interference of the two Raman transitions allows tunable negative refraction with low absorption.
A bivalent cationic dye enabling selective photo-inactivation against Gram-negative bacteria.

PubMed

Li, Ke; Zhang, Yang-Yang; Jiang, Guo-Yu; Hou, Yuan-Jun; Zhang, Bao-Wen; Zhou, Qian-Xiong; Wang, Xue-Song

2015-05-07

A piperazine-modified Crystal Violet was found to be able to selectively inactivate Gram-negative bacteria upon visible light irradiation but left Gram-positive bacteria less damaged, which can serve as a blueprint for the development of novel narrow-spectrum agents to replenish the current arsenal of photodynamic antimicrobial chemotherapy (PACT).
Stabilizing selection on sperm number revealed by artificial selection and experimental evolution.

PubMed

Cattelan, Silvia; Di Nisio, Andrea; Pilastro, Andrea

2018-03-01

Sperm competition is taxonomically widespread in animals and is usually associated with large sperm production, being the number of sperm in the competing pool the prime predictor of fertilization success. Despite the strong postcopulatory selection acting directionally on sperm production, its genetic variance is often very high. This can be explained by trade-offs between sperm production and traits associated with mate acquisition or survival, that may contribute to generate an overall stabilizing selection. To investigate this hypothesis, we first artificially selected male guppies (Poecilia reticulata) for high and low sperm production for three generations, while simultaneously removing sexual selection. Then, we interrupted artificial selection and restored sexual selection. Sperm production responded to divergent selection in one generation, and when we restored sexual selection, both high and low lines converged back to the mean sperm production of the original population within two generations, indicating that sperm number is subject to strong stabilizing total sexual selection (i.e., selection acting simultaneously on all traits associated with reproductive success). We discuss the possible mechanisms responsible for the maintenance of high genetic variability in sperm production despite strong selection acting on it. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.
The dynamics of diverse segmental amplifications in populations of Saccharomyces cerevisiae adapting to strong selection.

PubMed

Payen, Celia; Di Rienzi, Sara C; Ong, Giang T; Pogachar, Jamie L; Sanchez, Joseph C; Sunshine, Anna B; Raghuraman, M K; Brewer, Bonita J; Dunham, Maitreya J

2014-03-20

Population adaptation to strong selection can occur through the sequential or parallel accumulation of competing beneficial mutations. The dynamics, diversity, and rate of fixation of beneficial mutations within and between populations are still poorly understood. To study how the mutational landscape varies across populations during adaptation, we performed experimental evolution on seven parallel populations of Saccharomyces cerevisiae continuously cultured in limiting sulfate medium. By combining quantitative polymerase chain reaction, array comparative genomic hybridization, restriction digestion and contour-clamped homogeneous electric field gel electrophoresis, and whole-genome sequencing, we followed the trajectory of evolution to determine the identity and fate of beneficial mutations. During a period of 200 generations, the yeast populations displayed parallel evolutionary dynamics that were driven by the coexistence of independent beneficial mutations. Selective amplifications rapidly evolved under this selection pressure, in particular common inverted amplifications containing the sulfate transporter gene SUL1. Compared with single clones, detailed analysis of the populations uncovers a greater complexity whereby multiple subpopulations arise and compete despite a strong selection. The most common evolutionary adaptation to strong selection in these populations grown in sulfate limitation is determined by clonal interference, with adaptive variants both persisting and replacing one another.

The Dynamics of Diverse Segmental Amplifications in Populations of Saccharomyces cerevisiae Adapting to Strong Selection

PubMed Central

Payen, Celia; Di Rienzi, Sara C.; Ong, Giang T.; Pogachar, Jamie L.; Sanchez, Joseph C.; Sunshine, Anna B.; Raghuraman, M. K.; Brewer, Bonita J.; Dunham, Maitreya J.

2014-01-01

Population adaptation to strong selection can occur through the sequential or parallel accumulation of competing beneficial mutations. The dynamics, diversity, and rate of fixation of beneficial mutations within and between populations are still poorly understood. To study how the mutational landscape varies across populations during adaptation, we performed experimental evolution on seven parallel populations of Saccharomyces cerevisiae continuously cultured in limiting sulfate medium. By combining quantitative polymerase chain reaction, array comparative genomic hybridization, restriction digestion and contour-clamped homogeneous electric field gel electrophoresis, and whole-genome sequencing, we followed the trajectory of evolution to determine the identity and fate of beneficial mutations. During a period of 200 generations, the yeast populations displayed parallel evolutionary dynamics that were driven by the coexistence of independent beneficial mutations. Selective amplifications rapidly evolved under this selection pressure, in particular common inverted amplifications containing the sulfate transporter gene SUL1. Compared with single clones, detailed analysis of the populations uncovers a greater complexity whereby multiple subpopulations arise and compete despite a strong selection. The most common evolutionary adaptation to strong selection in these populations grown in sulfate limitation is determined by clonal interference, with adaptive variants both persisting and replacing one another. PMID:24368781
Could FIV zoonosis responsible of the breakdown of the pathocenosis which has reduced the European CCR5-Delta32 allele frequencies?

PubMed Central

Faure, Eric

2008-01-01

Background In Europe, the north-south downhill cline frequency of the chemokine receptor CCR5 allele with a 32-bp deletion (CCR5-Δ32) raises interesting questions for evolutionary biologists. We had suggested first that, in the past, the European colonizers, principally Romans, might have been instrumental of a progressively decrease of the frequencies southwards. Indeed, statistical analyses suggested strong negative correlations between the allele frequency and historical parameters including the colonization dates by Mediterranean civilisations. The gene flows from colonizers to native populations were extremely low but colonizers are responsible of the spread of several diseases suggesting that the dissemination of parasites in naive populations could have induced a breakdown rupture of the fragile pathocenosis changing the balance among diseases. The new equilibrium state has been reached through a negative selection of the null allele. Results Most of the human diseases are zoonoses and cat might have been instrumental in the decrease of the allele frequency, because its diffusion through Europe was a gradual process, due principally to Romans; and that several cat zoonoses could be transmitted to man. The possible implication of a feline lentivirus (FIV) which does not use CCR5 as co-receptor is discussed. This virus can infect primate cells in vitro and induces clinical signs in macaque. Moreover, most of the historical regions with null or low frequency of CCR5-Δ32 allele coincide with historical range of the wild felid species which harbor species-specific FIVs. Conclusion We proposed the hypothesis that the actual European CCR5 allelic frequencies are the result of a negative selection due to a disease spreading. A cat zoonosis, could be the most plausible hypothesis. Future studies could provide if CCR5 can play an antimicrobial role in FIV pathogenesis. Moreover, studies of ancient DNA could provide more evidences regarding the implications of zoonoses in the actual CCR5-Δ32 distribution. PMID:18925940
Type of monocyte immunomagnetic separation affects the morphology of monocyte-derived dendritic cells, as investigated by scanning electron microscopy.

PubMed

Kowalewicz-Kulbat, M; Ograczyk, E; Krawczyk, K; Rudnicka, W; Fol, M

2016-12-01

Dendritic cells (DCs) are increasingly being used for multiple applications and are useful tools for many immunotherapeutic strategies. The understanding of the possible impact of the DCs-generation methods on the biological capacities of these cells is therefore essential. Although the immunomagnetic separation is regarded as a fast and accurate method yielding cells with the high purity and efficiency, still little is known about its impact on the properties of the generated DCs. The aim of this study was to compare the morphology of the monocyte derived dendritic cells (MoDCs), generated from monocytes selected with anti-CD14 mAbs (positive separation) and treated with anti-CD3, -CD7, -CD16, -CD19, -CD56, -CD123, glycophorin A (negative separation), using laser scanning microscopy. We found that the type of the immunomagnetic separation method used strongly influences the shape and cell dimension of the MoDCs. We observed that the height of both immature and LPS-matured DCs generated from monocytes isolated by negative separation was significantly higher compared to the cells obtained by positive separation. Copyright Â© 2016 Elsevier B.V. All rights reserved.
Little effects of reduced-impact logging on insect communities in eastern Amazonia.

PubMed

Nogueira, Denis Silva; Calvão, Lenize Batista; de Assis Montag, Luciano Fogaça; Juen, Leandro; De Marco, Paulo

2016-07-01

Selective logging has become a major source of threats to tropical forest, bringing challenges for both ecologists and managers to develop low-impact forestry. Reduced-impact logging (RIL) is a prominent activity accounting for such forestry practices to prevent strong forest disturbances. Our aims were to evaluate the effects of RIL on insect communities of forested streams from Eastern Amazon and to test the hypothesis of negative effects of RIL on species richness, abundance, and functional feeding groups of aquatic insect assemblages. Neither of the evaluated metrics of the studied assemblages were negatively affected by RIL. Environmental metrics, such as substrate heterogeneity, woody canopy cover, and hill slope height, varied more among RIL streams than in reference streams, indicating a gradient according to logging impacts, and are suitable candidates to monitor RIL impacts in Amazonian streams. In addition, the PHI index also varied among REF and RIL, according to age class and year of logging, which could reflect trends to recover the forest structure after logging in a time frame of only 10 years. We conclude that RIL impacts have not had detrimental impacts on insect communities, but have changed little of the environmental conditions, especially of the riparian vegetation around streams.
The Cross-Cultural Loss Scale: development and psychometric evaluation.

PubMed

Wang, Kenneth T; Wei, Meifen; Zhao, Ran; Chuang, Chih-Chun; Li, Feihan

2015-03-01

The Cross-Cultural Loss Scale (CCLS), a measure of loss associated with crossing national boundaries, was developed across 2 samples of international students. With Sample 1 (N = 262), exploratory factor analyses were used to select the 14 CCLS items and to determine 3 factors: Belonging-Competency (α = .87), National Privileges (α = .68), and Access to Home Familiarity (α = .72). With Sample 2, confirmatory factor analyses (N = 256) cross-validated the 3-factor oblique model as well as a bifactor model. Cronbach alphas of CCLS subscale scores in Sample 2 ranged from .73 to .87. The validity of the CCLS scores was supported by its associations with related variables in the expected directions. Perceived cross-cultural losses were positively associated with negative affect, migration grief and loss, and discrimination and were negatively associated with life satisfaction, positive affect, general self-efficacy, and social connection with mainstream society. Moreover, the CCLS total and 2 subscale scores added significant incremental variance in predicting subjective well-being over and above related constructs. The results indicated measurement invariance and validity equivalency for the CCLS scores between men and women. The overall results from these 2 samples support CCLS as a psychometrically strong measure. 2015 APA, all rights reserved
Predicting the cosmological constant with the scale-factor cutoff measure

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Simone, Andrea; Guth, Alan H.; Salem, Michael P.

2008-09-15

It is well known that anthropic selection from a landscape with a flat prior distribution of cosmological constant {lambda} gives a reasonable fit to observation. However, a realistic model of the multiverse has a physical volume that diverges with time, and the predicted distribution of {lambda} depends on how the spacetime volume is regulated. A very promising method of regulation uses a scale-factor cutoff, which avoids a number of serious problems that arise in other approaches. In particular, the scale-factor cutoff avoids the 'youngness problem' (high probability of living in a much younger universe) and the 'Q and G catastrophes'more » (high probability for the primordial density contrast Q and gravitational constant G to have extremely large or small values). We apply the scale-factor cutoff measure to the probability distribution of {lambda}, considering both positive and negative values. The results are in good agreement with observation. In particular, the scale-factor cutoff strongly suppresses the probability for values of {lambda} that are more than about 10 times the observed value. We also discuss qualitatively the prediction for the density parameter {omega}, indicating that with this measure there is a possibility of detectable negative curvature.« less
The brain ages optimally to model its environment: evidence from sensory learning over the adult lifespan.

PubMed

Moran, Rosalyn J; Symmonds, Mkael; Dolan, Raymond J; Friston, Karl J

2014-01-01

The aging brain shows a progressive loss of neuropil, which is accompanied by subtle changes in neuronal plasticity, sensory learning and memory. Neurophysiologically, aging attenuates evoked responses--including the mismatch negativity (MMN). This is accompanied by a shift in cortical responsivity from sensory (posterior) regions to executive (anterior) regions, which has been interpreted as a compensatory response for cognitive decline. Theoretical neurobiology offers a simpler explanation for all of these effects--from a Bayesian perspective, as the brain is progressively optimized to model its world, its complexity will decrease. A corollary of this complexity reduction is an attenuation of Bayesian updating or sensory learning. Here we confirmed this hypothesis using magnetoencephalographic recordings of the mismatch negativity elicited in a large cohort of human subjects, in their third to ninth decade. Employing dynamic causal modeling to assay the synaptic mechanisms underlying these non-invasive recordings, we found a selective age-related attenuation of synaptic connectivity changes that underpin rapid sensory learning. In contrast, baseline synaptic connectivity strengths were consistently strong over the decades. Our findings suggest that the lifetime accrual of sensory experience optimizes functional brain architectures to enable efficient and generalizable predictions of the world.
Twistacene contained molecule for optical nonlinearity: Excited-state based negative refraction and optical limiting

NASA Astrophysics Data System (ADS)

Wu, Xingzhi; Xiao, Jinchong; Sun, Ru; Jia, Jidong; Yang, Junyi; Ao, Guanghong; Shi, Guang; Wang, Yuxiao; Zhang, Xueru; Song, Yinglin

2018-06-01

Spindle-type molecules containing twisted acenes (PyBTA-1 &PyBTA-2) are designed, synthesized characterized. Picosecond Z-scan experiments under 532 nm show reverse saturable absorption and negative nonlinear refraction, indicating large third-order optical nonlinearity in PyBTA-1. The mechanism of the optical nonlinearity is investigated and the results show that the nonlinear absorption and refraction in PyBTA-1 originates from a charge transfer (CT) state. Furthermore, relatively long lifetime and absorptive cross section of the CT state are measured. Based on the excited state absorption in PyBTA-1, strong optical limiting with ∼0.3 J/cm2 thresholds are obtained when excited by picoseconds and nanoseconds pulses. The findings on nonlinear optics suggest PyBTA-1 a promising material of all optical modulation and laser protection, which enrich the potential applications of these spindle-type molecules. Comparing to the previously reported spindle-type molecules with analogous structures, the introduction of ICT in PyBTA-1 &PyBTA-2 dramatically decreases the two-photon absorption while enhances the nonlinear refraction. The results could be used to selectively tailor the optical nonlinearity in such kind of compounds.
Substance Use as a Strong Predictor of Poor Academic Achievement among University Students

PubMed Central

Fekadu, Wubalem; Mekonnen, Tefera Chane; Workie, Shimelash Bitew

2017-01-01

Background Substance use is a growing concern globally and its association with students' academic performance is not well studied. Objective This study was aimed to assess the prevalence of substance use (alcohol, tobacco, and khat) and its association with academic performance among university students. Methods Cross-sectional study was conducted among Wolaita Sodo University students. A total of 747 students were selected by using cluster sampling technique. Data were collected by pretested self-administered questionnaire and examined using descriptive statistics and linear regression with 95% confidence intervals. Variables with p value of less than 0.05 were considered as statistically significant. Result Prevalence of substance use (alcohol, tobacco, and khat) was 28.6%. Substance use (current smoking, chewing khat at least weekly, drinking alcohol on a daily basis, and having intimate friend who uses substance) was significantly and negatively associated with students' academic performance. Conclusion Substance use among Wolaita Sodo University students was as common as other studies in Sub-Saharan countries and negatively associated with students' academic achievement. The common practice of substance use and its association with poor academic performance demand the universities to have a good control of substance and to implement youth friendly activities. PMID:28680879
Short communication: Preliminary investigation into the effect of freezing and a cryopreservant on the recovery of mastitis pathogens from ewe milk.

PubMed

Smith, E M; Monaghan, E M; Huntley, S J; Green, L E

2011-10-01

The objective of this study was to investigate the recovery of bacteria from ewe milk after freezing for 4 or 8 wk with and without the addition of glycerol as a cryopreservant. A total of 50 udder-half milk samples with a known range of bacterial species were selected, stored, and analyzed in 5 treatment groups: time zero; frozen for 4 wk with, and without, glycerol; and frozen for 8 wk with, and without, glycerol. A lower recovery was observed in all bacterial species studied after freezing. Samples containing fewer than 100 cfu/mL came from ewes with a lower somatic cell count and were more likely to be bacteriologically negative after freezing than those above this threshold. The addition of glycerol increased recovery of gram-negative bacteria after freezing, although this requires further study to draw strong conclusions. The effects on gram-positive species were inconsistent. We conclude that although the addition of glycerol had a small beneficial effect on the sensitivity of detection of bacteria from frozen sheep milk, sensitivity was highest in cultures from fresh milk. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Effect of wheat flour characteristics on sponge cake quality.

PubMed

Moiraghi, Malena; de la Hera, Esther; Pérez, Gabriela T; Gómez, Manuel

2013-02-01

To select the flour parameters that relate strongly to cake-making performance, in this study the relationship between sponge cake quality, solvent retention capacity (SRC) profile and flour physicochemical characteristics was investigated using 38 soft wheat samples of different origins. Particle size average, protein, damaged starch, water-soluble pentosans, total pentosans, SRC and pasting properties were analysed. Sponge cake volume and crumb texture were measured to evaluate cake quality. Cluster analysis was applied to assess differences in flour quality parameters among wheat lines based on the SRC profile. Cluster 1 showed significantly higher sponge cake volume and crumb softness, finer particle size and lower SRC sucrose, SRC carbonate, SRC water, damaged starch and protein content. Particle size, damaged starch, protein, thickening capacity and SRC parameters correlated negatively with sponge cake volume, while total pentosans and pasting temperature showed the opposite effect. The negative correlations between cake volume and SRC parameters along with the cluster analysis results indicated that flours with smaller particle size, lower absorption capacity and higher pasting temperature had better cake-making performance. Some simple analyses, such as SRC, particle size distribution and pasting properties, may help to choose flours suitable for cake making. Copyright © 2012 Society of Chemical Industry.
Bactericidal catechins damage the lipid bilayer.

PubMed

Ikigai, H; Nakae, T; Hara, Y; Shimamura, T

1993-04-08

The mode of antibacterial action of, the green tea (Camellia sinensis) extracts, (-)-epigallocatechin gallate (EGCg) and (-)-epicatechin (EC) was investigated. Strong bactericidal EGCg caused leakage of 5,6-carboxyfluorescein from phosphatidylcholine liposomes (PC), but EC with very weak bactericidal activity caused little damage to the membrane. Phosphatidylserine and dicetyl phosphate partially protected the membrane from EGCg-mediated damage when reconstituted into the liposome membrane with PC. EGCg, but not EC, caused strong aggregation and NPN-fluorescence quenching of PC-liposomes and these actions were markedly lowered in the presence of negatively charged lipids. These results show that bactericidal catechins primarily act on and damage bacterial membranes. The observation that Gram-negative bacteria are more resistant to bactericidal catechins than Gram-positive bacteria can be explained to some extent by the presence of negatively charged lipopolysaccharide.
Role of commitment to the supervisor, leader-member exchange, and supervisor-based self-esteem in employee-supervisor conflicts.

PubMed

Landry, Guylaine; Vandenberghe, Christian

2009-02-01

Using survey data from 240 employees working in a variety of organizations, the authors examined the relations among commitment to the supervisor, leader-member exchange, supervisor-based self-esteem (SBSE), and relationship and substantive supervisor-subordinate conflicts. They found affective commitment was negatively related to both types of conflicts; perceived lack of alternatives commitment was positively related to relationship conflicts; and leader-member exchange was negatively related to substantive conflicts. SBSE was negatively associated with both types of conflicts. In addition, when SBSE was low, affective commitment was more strongly related to both types of conflicts, and normative commitment more strongly and positively related to substantive conflicts. The authors discuss the implications of these findings for the understanding of employee-supervisor conflicts.
The negative priming paradigm: An update and implications for selective attention.

PubMed

Frings, Christian; Schneider, Katja Kerstin; Fox, Elaine

2015-12-01

Negative Priming (NP) is an influential paradigm in cognitive psychology that was originally developed to measure attentional selection. Yet, up to the mid-1990s, a large number of experimental reports questioned whether the NP effect is based on attentional inhibition and/or episodic retrieval processes. In this review, we summarize findings since the mid-1990s and discuss new and old theoretical approaches to Negative Priming. We conclude that more than one process contributes to NP and that future research should analyze the conditions under which a particular process contributes to NP. Moreover, we argue that the paradigm--although it does not measure a single cognitive process alone--is still a useful tool for understanding selection in cognition. In fact, it might be a virtue of the paradigm that several cognitive processes work here together as selection in nonexperimental contexts is surely a multidimensional process. From this perspective, research on NP is relevant for all research fields analyzing selection. We therefore close our review by discussing the implications of the new evidence on NP for theories of selective attention.
Selection of GP. Mur antigen-negative RBC for blood recipients with anti-'Mia ' records decreases transfusion reaction rates in Taiwan.

PubMed

Yang, C-A; Lin, J-A; Chang, C-W; Wu, K-H; Yeh, S-P; Ho, C-M; Chang, J-G

2016-10-01

To evaluate the clinical significance of GP. Mur antigen-negative blood selection for transfusion in patients with anti-'Mi a ' records. The GP. Mur RBC phenotype is prevalent (7·3%) in Taiwan. Antibodies against GP. Mur (anti-'Mi a ') are identified in 1·24% of our population, and anti-'Mi a ' screening using GP. Mur RBC has been routine for Taiwan's blood banks. However, due to the lack of commercial antibodies, only cross-matching was used to prevent transfusion of GP. Mur-positive blood to patients with anti-'Mi a ' in most hospitals. There is still a risk of GP. Mur-positive RBC exposure and subsequent anti-'Mi a '-related transfusion reactions. Since February 2014, GP. Mur antigen-negative RBCs identified by reaction with anti-'Mi a '-positive serum were selected for blood recipients with anti-'Mi a ' records. The transfusion reactions between January 2013 and January 2014 were compared with those that occurred between February 2014 and July 2015. The transfusion reaction rate was significantly higher in anti-'Mi a '-positive blood recipients compared to total subjects receiving an RBC transfusion before GP. Mur-negative donor RBC selection. After antigen-negative RBC selection, the transfusion reaction frequency in subjects with anti-'Mi a ' became similar to total blood recipients. IgG form anti-'Mi a ' antibodies were present in all cases of probable anti-'Mi a '-related transfusion reactions. The time required for anti-'Mi a ' boosting after transfusion was around 4-21 days. Selection of GP. Mur-negative RBC for transfusion to patients with anti-'Mi a ' records could decrease the rate of transfusion reaction and antibody boosting. This procedure should be incorporated into blood bank routines in areas where anti-'Mi a ' is prevalent. © 2016 British Blood Transfusion Society.
Genetic diversity and natural selection of Plasmodium knowlesi merozoite surface protein 1 paralog gene in Malaysia.

PubMed

Ahmed, Md Atique; Fauzi, Muh; Han, Eun-Taek

2018-03-14

Human infections due to the monkey malaria parasite Plasmodium knowlesi is on the rise in most Southeast Asian countries specifically Malaysia. The C-terminal 19 kDa domain of PvMSP1P is a potential vaccine candidate, however, no study has been conducted in the orthologous gene of P. knowlesi. This study investigates level of polymorphisms, haplotypes and natural selection of full-length pkmsp1p in clinical samples from Malaysia. A total of 36 full-length pkmsp1p sequences along with the reference H-strain and 40 C-terminal pkmsp1p sequences from clinical isolates of Malaysia were downloaded from published genomes. Genetic diversity, polymorphism, haplotype and natural selection were determined using DnaSP 5.10 and MEGA 5.0 software. Genealogical relationships were determined using haplotype network tree in NETWORK software v5.0. Population genetic differentiation index (F ST ) and population structure of parasite was determined using Arlequin v3.5 and STRUCTURE v2.3.4 software. Comparison of 36 full-length pkmsp1p sequences along with the H-strain identified 339 SNPs (175 non-synonymous and 164 synonymous substitutions). The nucleotide diversity across the full-length gene was low compared to its ortholog pvmsp1p. The nucleotide diversity was higher toward the N-terminal domains (pkmsp1p-83 and 30) compared to the C-terminal domains (pkmsp1p-38, 33 and 19). Phylogenetic analysis of full-length genes identified 2 distinct clusters of P. knowlesi from Malaysian Borneo. The 40 pkmsp1p-19 sequences showed low polymorphisms with 16 polymorphisms leading to 18 haplotypes. In total there were 10 synonymous and 6 non-synonymous substitutions and 12 cysteine residues were intact within the two EGF domains. Evidence of strong purifying selection was observed within the full-length sequences as well in all the domains. Shared haplotypes of 40 pkmsp1p-19 were identified within Malaysian Borneo haplotypes. This study is the first to report on the genetic diversity and natural selection of pkmsp1p. A low level of genetic diversity and strong evidence of negative selection was detected and observed in all the domains of pkmsp1p of P. knowlesi indicating functional constrains. Shared haplotypes were identified within pkmsp1p-19 highlighting further evaluation using larger number of clinical samples from Malaysia.
Strong Selection at MHC in Mexicans since Admixture

PubMed Central

Zhou, Quan; Zhao, Liang; Guan, Yongtao

2016-01-01

Mexicans are a recent admixture of Amerindians, Europeans, and Africans. We performed local ancestry analysis of Mexican samples from two genome-wide association studies obtained from dbGaP, and discovered that at the MHC region Mexicans have excessive African ancestral alleles compared to the rest of the genome, which is the hallmark of recent selection for admixed samples. The estimated selection coefficients are 0.05 and 0.07 for two datasets, which put our finding among the strongest known selections observed in humans, namely, lactase selection in northern Europeans and sickle-cell trait in Africans. Using inaccurate Amerindian training samples was a major concern for the credibility of previously reported selection signals in Latinos. Taking advantage of the flexibility of our statistical model, we devised a model fitting technique that can learn Amerindian ancestral haplotype from the admixed samples, which allows us to infer local ancestries for Mexicans using only European and African training samples. The strong selection signal at the MHC remains without Amerindian training samples. Finally, we note that medical history studies suggest such a strong selection at MHC is plausible in Mexicans. PMID:26863142
Joint effects of emotion and color on memory.

PubMed

Kuhbandner, Christof; Pekrun, Reinhard

2013-06-01

Numerous studies have shown that memory is enhanced for emotionally negative and positive information relative to neutral information. We examined whether emotion-induced memory enhancement is influenced by low-level perceptual attributes such as color. Because in everyday life red is often used as a warning signal, whereas green signals security, we hypothesized that red might enhance memory for negative information and green memory for positive information. To capture the signaling function of colors, we measured memory for words standing out from the context by color, and manipulated the color and emotional significance of the outstanding words. Making words outstanding by color strongly enhanced memory, replicating the well-known von Restorff effect. Furthermore, memory for colored words was further increased by emotional significance, replicating the memory-enhancing effect of emotion. Most intriguingly, the effects of emotion on memory additionally depended on color type. Red strongly increased memory for negative words, whereas green strongly increased memory for positive words. These findings provide the first evidence that emotion-induced memory enhancement is influenced by color and demonstrate that different colors can have different functions in human memory.
Bigger Is Fitter? Quantitative Genetic Decomposition of Selection Reveals an Adaptive Evolutionary Decline of Body Mass in a Wild Rodent Population.

PubMed

Bonnet, Timothée; Wandeler, Peter; Camenisch, Glauco; Postma, Erik

2017-01-01

In natural populations, quantitative trait dynamics often do not appear to follow evolutionary predictions. Despite abundant examples of natural selection acting on heritable traits, conclusive evidence for contemporary adaptive evolution remains rare for wild vertebrate populations, and phenotypic stasis seems to be the norm. This so-called "stasis paradox" highlights our inability to predict evolutionary change, which is especially concerning within the context of rapid anthropogenic environmental change. While the causes underlying the stasis paradox are hotly debated, comprehensive attempts aiming at a resolution are lacking. Here, we apply a quantitative genetic framework to individual-based long-term data for a wild rodent population and show that despite a positive association between body mass and fitness, there has been a genetic change towards lower body mass. The latter represents an adaptive response to viability selection favouring juveniles growing up to become relatively small adults, i.e., with a low potential adult mass, which presumably complete their development earlier. This selection is particularly strong towards the end of the snow-free season, and it has intensified in recent years, coinciding which a change in snowfall patterns. Importantly, neither the negative evolutionary change, nor the selective pressures that drive it, are apparent on the phenotypic level, where they are masked by phenotypic plasticity and a non causal (i.e., non genetic) positive association between body mass and fitness, respectively. Estimating selection at the genetic level enabled us to uncover adaptive evolution in action and to identify the corresponding phenotypic selective pressure. We thereby demonstrate that natural populations can show a rapid and adaptive evolutionary response to a novel selective pressure, and that explicitly (quantitative) genetic models are able to provide us with an understanding of the causes and consequences of selection that is superior to purely phenotypic estimates of selection and evolutionary change.
Bigger Is Fitter? Quantitative Genetic Decomposition of Selection Reveals an Adaptive Evolutionary Decline of Body Mass in a Wild Rodent Population

PubMed Central

Wandeler, Peter; Camenisch, Glauco

2017-01-01

In natural populations, quantitative trait dynamics often do not appear to follow evolutionary predictions. Despite abundant examples of natural selection acting on heritable traits, conclusive evidence for contemporary adaptive evolution remains rare for wild vertebrate populations, and phenotypic stasis seems to be the norm. This so-called “stasis paradox” highlights our inability to predict evolutionary change, which is especially concerning within the context of rapid anthropogenic environmental change. While the causes underlying the stasis paradox are hotly debated, comprehensive attempts aiming at a resolution are lacking. Here, we apply a quantitative genetic framework to individual-based long-term data for a wild rodent population and show that despite a positive association between body mass and fitness, there has been a genetic change towards lower body mass. The latter represents an adaptive response to viability selection favouring juveniles growing up to become relatively small adults, i.e., with a low potential adult mass, which presumably complete their development earlier. This selection is particularly strong towards the end of the snow-free season, and it has intensified in recent years, coinciding which a change in snowfall patterns. Importantly, neither the negative evolutionary change, nor the selective pressures that drive it, are apparent on the phenotypic level, where they are masked by phenotypic plasticity and a non causal (i.e., non genetic) positive association between body mass and fitness, respectively. Estimating selection at the genetic level enabled us to uncover adaptive evolution in action and to identify the corresponding phenotypic selective pressure. We thereby demonstrate that natural populations can show a rapid and adaptive evolutionary response to a novel selective pressure, and that explicitly (quantitative) genetic models are able to provide us with an understanding of the causes and consequences of selection that is superior to purely phenotypic estimates of selection and evolutionary change. PMID:28125583

The complexity of selection at the major primate β-defensin locus

PubMed Central

Semple, Colin AM; Maxwell, Alison; Gautier, Philippe; Kilanowski, Fiona M; Eastwood, Hayden; Barran, Perdita E; Dorin, Julia R

2005-01-01

Background We have examined the evolution of the genes at the major human β-defensin locus and the orthologous loci in a range of other primates and mouse. For the first time these data allow us to examine selective episodes in the more recent evolutionary history of this locus as well as the ancient past. We have used a combination of maximum likelihood based tests and a maximum parsimony based sliding window approach to give a detailed view of the varying modes of selection operating at this locus. Results We provide evidence for strong positive selection soon after the duplication of these genes within an ancestral mammalian genome. Consequently variable selective pressures have acted on β-defensin genes in different evolutionary lineages, with episodes both of negative, and more rarely positive selection, during the divergence of primates. Positive selection appears to have been more common in the rodent lineage, accompanying the birth of novel, rodent-specific β-defensin genes. These observations allow a fuller understanding of the evolution of mammalian innate immunity. In both the rodent and primate lineages, sites in the second exon have been subject to positive selection and by implication are important in functional diversity. A small number of sites in the mature human peptides were found to have undergone repeated episodes of selection in different primate lineages. Particular sites were consistently implicated by multiple methods at positions throughout the mature peptides. These sites are clustered at positions predicted to be important for the specificity of the antimicrobial or chemoattractant properties of β-defensins. Surprisingly, sites within the prepropeptide region were also implicated as being subject to significant positive selection, suggesting previously unappreciated functional significance for this region. Conclusions Identification of these putatively functional sites has important implications for our understanding of β-defensin function and for novel antibiotic design. PMID:15904491
Intra-Personal and Inter-Personal Kinetic Synergies During Jumping.

PubMed

Slomka, Kajetan; Juras, Grzegorz; Sobota, Grzegorz; Furmanek, Mariusz; Rzepko, Marian; Latash, Mark L

2015-12-22

We explored synergies between two legs and two subjects during preparation for a long jump into a target. Synergies were expected during one-person jumping. No such synergies were expected between two persons jumping in parallel without additional contact, while synergies were expected to emerge with haptic contact and become stronger with strong mechanical contact. Subjects performed jumps either alone (each foot standing on a separate force platform) or in dyads (parallel to each other, each person standing on a separate force platform) without any contact, with haptic contact, and with strong coupling. Strong negative correlations between pairs of force variables (strong synergies) were seen in the vertical force in one-person jumps and weaker synergies in two-person jumps with the strong contact. For other force variables, only weak synergies were present in one-person jumps and no negative correlations between pairs of force variable for two-person jumps. Pairs of moment variables from the two force platforms at steady state showed positive correlations, which were strong in one-person jumps and weaker, but still significant, in two-person jumps with the haptic and strong contact. Anticipatory synergy adjustments prior to action initiation were observed in one-person trials only. We interpret the different results for the force and moment variables at steady state as reflections of postural sway.
Intra-Personal and Inter-Personal Kinetic Synergies During Jumping

PubMed Central

Slomka, Kajetan; Juras, Grzegorz; Sobota, Grzegorz; Furmanek, Mariusz; Rzepko, Marian; Latash, Mark L.

2015-01-01

We explored synergies between two legs and two subjects during preparation for a long jump into a target. Synergies were expected during one-person jumping. No such synergies were expected between two persons jumping in parallel without additional contact, while synergies were expected to emerge with haptic contact and become stronger with strong mechanical contact. Subjects performed jumps either alone (each foot standing on a separate force platform) or in dyads (parallel to each other, each person standing on a separate force platform) without any contact, with haptic contact, and with strong coupling. Strong negative correlations between pairs of force variables (strong synergies) were seen in the vertical force in one-person jumps and weaker synergies in two-person jumps with the strong contact. For other force variables, only weak synergies were present in one-person jumps and no negative correlations between pairs of force variable for two-person jumps. Pairs of moment variables from the two force platforms at steady state showed positive correlations, which were strong in one-person jumps and weaker, but still significant, in two-person jumps with the haptic and strong contact. Anticipatory synergy adjustments prior to action initiation were observed in one-person trials only. We interpret the different results for the force and moment variables at steady state as reflections of postural sway. PMID:26839608
MHC class II DRB diversity in raccoons (Procyon lotor) reveals associations with raccoon rabies virus (Lyssavirus).

PubMed

Srithayakumar, Vythegi; Castillo, Sarrah; Rosatte, Rick C; Kyle, Christopher J

2011-02-01

In North America, the raccoon rabies virus (RRV) is an endemic wildlife disease which causes acute encephalopathies and is a strong selective force on raccoons (Procyon lotor), with estimates of ∼85% of the population succumbing to the disease when epizootic. RRV is regarded as a lethal disease if untreated; therefore, no evolutionary response would be expected of raccoon populations. However, variable immune responses to RRV have been observed in raccoons indicating a potential for evolutionary adaptation. Studies of variation within the immunologically important major histocompatibility complex (MHC) have revealed relationships between MHC alleles and diseases in humans and other wildlife species. This enhances our understanding of how hosts and pathogens adapt and co-evolve. In this study, we used RRV as a model system to study host-pathogen interaction in raccoons from a challenge study and from four wild populations that differ in exposure times and viral lineages. We investigated the potential role of Prlo-DRB polymorphism in relation to susceptibility/resistance to RRV in 113 RRV positive and 143 RRV negative raccoons. Six alleles were found to be associated with RRV negative status and five alleles with RRV positive animals. We found variable patterns of MHC associations given the relative number of selective RRV sweeps in the studied regions and correlations between MHC diversity and RRV lineages. The allelic associations established provide insight into how the genetic variation of raccoons may affect the disease outcome and this can be used to examine similar associations between other rabies variants and their hosts.
Low level exposure to inorganic mercury interferes with B cell receptor signaling in transitional type 1 B cells.

PubMed

Gill, R; McCabe, M J; Rosenspire, A J

2017-09-01

Mercury (Hg) has been implicated as a factor contributing to autoimmune disease in animal models and humans. However the mechanism by which this occurs has remained elusive. Since the discovery of B cells it has been appreciated by immunologists that during the normal course of B cell development, some immature B cells must be generated that produce immunoglobulin reactive to self-antigens (auto-antibodies). However in the course of normal development, the vast majority of immature auto-reactive B cells are prevented from maturing by processes collectively known as tolerance. Autoimmune disease arises when these mechanisms of tolerance are disrupted. In the B cell compartment, it is firmly established that tolerance depends in part upon negative selection of self-reactive immature (transitional type 1) B cells. In these cells negative selection depends upon signals generated by the B Cell Receptor (BCR), in the sense that those T1 B cells who's BCRs most strongly bind to, and so generate the strongest signals to self-antigens are neutralized. In this report we have utilized multicolor phosphoflow cytometry to show that in immature T1 B cells Hg attenuates signal generation by the BCR through mechanisms that may involve Lyn, a key tyrosine kinase in the BCR signal transduction pathway. We suggest that exposure to low, environmentally relevant levels of Hg, disrupts tolerance by interfering with BCR signaling in immature B cells, potentially leading to the appearance of mature auto-reactive B cells which have the ability to contribute to auto-immune disease. Copyright © 2017 Elsevier Inc. All rights reserved.
Multiple deleterious effects of experimentally aged sperm in a monogamous bird

USGS Publications Warehouse

White, J.; Wagner, R.H.; Helfenstein, F.; Hatch, Shyla A.; Mulard, Hervé; Naves, L.C.; Danchin, E.

2008-01-01

Sperm aging is known to be detrimental to reproductive performance. However, this apparently general phenomenon has seldom been studied in an evolutionary context. The negative impact of sperm aging on parental fitness should constitute a strong selective pressure for adaptations to avoid its effects. We studied the impact of sperm aging on black-legged kittiwakes (Rissa tridactyla), a monogamous seabird. Kittiwakes comprise a model system because (i) of evidence that females eject their mates' sperm to prevent fertilization by sperm that would be old and degraded by the time of fertilization and result in reduced reproductive performance and (ii) the lack of extra-pair fertilization in this species makes cryptic female choice an unlikely explanation of postcopulatory sperm ejection by females. We experimentally manipulated the age of the sperm fertilizing kittiwake eggs by fitting males with anti-insemination rings for variable periods of time preceding egg-laying. We found evidence that sperm aging negatively affected four sequential stages of reproduction: fertilization potential, rate of embryonic development, embryonic mortality, and chick condition at hatching. These results may be produced by a continuum of a single process of sperm aging that differentially affects various aspects of development, depending on the degree of damage incurred to the spermatozoa. The marked impact of sperm age on female fitness may thus drive postcopulatory sperm ejection by females. These results provide experimental evidence of deleterious effects of sperm aging on a nondomestic vertebrate, underlining its taxonomic generality and its potential to select for a wide array of adaptations. ?? 2008 by The National Academy of Sciences of the USA.
Apoptosis induction by 7-chloroquinoline-1,2,3-triazoyl carboxamides in triple negative breast cancer cells.

PubMed

Begnini, Karine Rech; Duarte, Wladimir R; da Silva, Liziane Pereira; Buss, Julieti H; Goldani, Bruna S; Fronza, Mariana; Segatto, Natália Vieira; Alves, Diego; Savegnago, Lucielli; Seixas, Fabiana Kömmling; Collares, Tiago

2017-07-01

Breast cancer is a major public health burden in both developed and developing countries and there is still a need to screen new molecules with different modes of actions. The aims of this study were to evaluate the selectivity profile, apoptotic cell death and cell cycle arrest induced by 7-chloroquinoline-1,2,3-triazoyl carboxamides derivatives in hormonal-dependent and hormonal-independent breast cancer cells. Results showed significantly decreased MCF-7 and MDA-MB-231 cells viability in vitro in a dose dependent manner after treatment with 7-chloroquinoline derivatives QTCA-1, QTCA-2 and QTCA-3. QTCA-1 displayed the highest cytotoxic activity from all the tested compounds in MDA-MB-231 with IC50 values of 20.60, 20.42 and 19.91μM in 24, 48 and 72h of treatment respectively. Apoptosis induction was also significantly higher in the hormonal-independent breast cancer cells, with 80.4% of dead cells in MDA-MB-231 and only 16.8% of dead in MCF-7 cells. As a result, G0/G1 cycle arrest was observed in MCF-7 cells and no cell cycle arrest at all was observed in MDA-MB-231 cells. Molecular docking showed a high affinity of QTCA-1 to PARP-1, Scr and PI3K/mTOR targets. These results suggest a strong activity of the 7-chloroquinoline derivative QTCA-1 in independent-hormonal cells and suggest selectivity for triple negative cells. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
Do practitioners and friends support patients with coronary heart disease in lifestyle change? a qualitative study.

PubMed

Cole, Judith A; Smith, Susan M; Hart, Nigel; Cupples, Margaret E

2013-08-28

Healthy lifestyles help to prevent coronary heart disease (CHD) but outcomes from secondary prevention interventions which support lifestyle change have been disappointing. This study is a novel, in-depth exploration of patient factors affecting lifestyle behaviour change within an intervention designed to improve secondary prevention for patients with CHD in primary care using personalised tailored support. We aimed to explore patients' perceptions of factors affecting lifestyle change within a trial of this intervention (the SPHERE Study), using semi-structured, one-to-one interviews, with patients in general practice. Interviews (45) were conducted in purposively selected general practices (15) which had participated in the SPHERE Study. Individuals, with CHD, were selected to include those who succeeded in improving physical activity levels and dietary fibre intake and those who did not. We explored motivations, barriers to lifestyle change and information utilised by patients. Data collection and analysis, using a thematic framework and the constant comparative method, were iterative, continuing until data saturation was achieved. We identified novel barriers to lifestyle change: such disincentives included strong negative influences of social networks, linked to cultural norms which encouraged consumption of 'delicious' but unhealthy food and discouraged engagement in physical activity. Findings illustrated how personalised support within an ongoing trusted patient-professional relationship was valued. Previously known barriers and facilitators relating to support, beliefs and information were confirmed. Intervention development in supporting lifestyle change in secondary prevention needs to more effectively address patients' difficulties in overcoming negative social influences and maintaining interest in living healthily.
Evaluation of interventions on road traffic injuries in Peru: a qualitative approach

PubMed Central

2012-01-01

Background Evaluation of interventions on road traffic injuries (RTI) going beyond the assessment of impact to include factors underlying success or failure is an important complement to standard impact evaluations. We report here how we used a qualitative approach to assess current interventions implemented to reduce RTIs in Peru. Methods We performed in-depth interviews with policymakers and technical officers involved in the implementation of RTI interventions to get their insight on design, implementation and evaluation aspects. We then conducted a workshop with key stakeholders to analyze the results of in-depth interviews, and to further discuss and identify key programmatic considerations when designing and implementing RTI interventions. We finally performed brainstorming sessions to assess potential system-wide effects of a selected intervention (Zero Tolerance), and to identify adaptation and redesign needs for this intervention. Results Key programmatic components were consistently identified that should be considered when designing and implementing RTI interventions. They include effective and sustained political commitment and planning; sufficient and sustained budget allocation; training, supervision, monitoring and evaluation of implemented policies; multisectoral participation; and strong governance and accountability. Brainstorming sessions revealed major negative effects of the selected intervention on various system building blocks. Conclusions Our approach revealed substantial caveats in current RTI interventions in Peru, and fundamental negative effects on several components of the sectors and systems involved. It also highlighted programmatic issues that should be applied to guarantee an effective implementation and evaluation of these policies. The findings from this study were discussed with key stakeholders for consideration in further designing and planning RTI control interventions in Peru. PMID:22269578
Evaluation of interventions on road traffic injuries in Peru: a qualitative approach.

PubMed

Huicho, Luis; Adam, Taghreed; Rosales, Edmundo; Paca-Palao, Ada; López, Luis; Luna, Diego; Miranda, J Jaime

2012-01-23

Evaluation of interventions on road traffic injuries (RTI) going beyond the assessment of impact to include factors underlying success or failure is an important complement to standard impact evaluations. We report here how we used a qualitative approach to assess current interventions implemented to reduce RTIs in Peru. We performed in-depth interviews with policymakers and technical officers involved in the implementation of RTI interventions to get their insight on design, implementation and evaluation aspects. We then conducted a workshop with key stakeholders to analyze the results of in-depth interviews, and to further discuss and identify key programmatic considerations when designing and implementing RTI interventions. We finally performed brainstorming sessions to assess potential system-wide effects of a selected intervention (Zero Tolerance), and to identify adaptation and redesign needs for this intervention. Key programmatic components were consistently identified that should be considered when designing and implementing RTI interventions. They include effective and sustained political commitment and planning; sufficient and sustained budget allocation; training, supervision, monitoring and evaluation of implemented policies; multisectoral participation; and strong governance and accountability. Brainstorming sessions revealed major negative effects of the selected intervention on various system building blocks. Our approach revealed substantial caveats in current RTI interventions in Peru, and fundamental negative effects on several components of the sectors and systems involved. It also highlighted programmatic issues that should be applied to guarantee an effective implementation and evaluation of these policies. The findings from this study were discussed with key stakeholders for consideration in further designing and planning RTI control interventions in Peru.
Optical performance and metallic absorption in nanoplasmonic systems.

PubMed

Arnold, Matthew D; Blaber, Martin G

2009-03-02

Optical metrics relating to metallic absorption in representative plasmonic systems are surveyed, with a view to developing heuristics for optimizing performance over a range of applications. We use the real part of the permittivity as the independent variable; consider strengths of particle resonances, resolving power of planar lenses, and guiding lengths of planar waveguides; and compare nearly-free-electron metals including Al, Cu, Ag, Au, Li, Na, and K. Whilst the imaginary part of metal permittivity has a strong damping effect, field distribution is equally important and thus factors including geometry, real permittivity and frequency must be considered when selecting a metal. Al performs well at low permittivities (e.g. sphere resonances, superlenses) whereas Au & Ag only perform well at very negative permittivities (shell and rod resonances, LRSPP). The alkali metals perform well overall but present engineering challenges.
Sexual Conflict and Sperm Competition

PubMed Central

Edward, Dominic A.; Stockley, Paula; Hosken, David J.

2015-01-01

Traits that increase a male’s fertilization success during sperm competition can be harmful to females and therefore represent a source of sexual conflict. In this review, we consider the variety of male adaptations to sperm competition (MASC) that may give rise to sexual conflict—including mate guarding, prolonged copulations, the transfer of large numbers of sperm, and the manipulation of females through nonsperm components of the ejaculate. We then reflect on the fitness economics influencing the escalation of these sexual conflicts, considering the likelihood of females evolving traits to offset the negative effects of MASC when compared with the strong selection on males that lead to MASC. We conclude by discussing the potential evolutionary outcomes of sexual conflict arising from MASC, including the opportunities for females to mitigate conflict costs and the prospects for conflict resolution. PMID:25301931
Role of chronic exercise on pelvic floor support and function

PubMed Central

Shaw, Janet M.; Nygaard, Ingrid E.

2017-01-01

Purpose of review To summarize recent literature about the potential role of chronic exercise on pelvic floor support and function. Recent findings Stress urinary incontinence is common during physical activity. Scant evidence suggests a dose-response association between higher volumes of exercise and urinary incontinence. Athletes do not appear to have greater pelvic floor muscle strength or worse pelvic floor support compared to non-athletes. Pelvic floor muscle electromyographic activity increases substantially as running speeds increase. Summary Based on the current literature, no strong conclusions can be drawn about whether chronic exercise exerts a positive or negative influence on pelvic floor support and function. Adopting longitudinal research methodology that prospectively monitors exercise exposure and subsequent changes in pelvic floor support and function would help to reduce selection bias associated with cross sectional studies on groups of athletes. PMID:28212118
Hypochondriasis and somatization in college women: a personal projects analysis.

PubMed

Karoly, P; Lecci, L

1993-03-01

Although the descriptive features of hypochondriasis and somatization have been widely studied, the motivational correlates (goal representations) of individuals manifesting abnormal illness patterns have not been considered. The Personal Projects Analysis method (Little, 1983) was used to contrast the health and nonhealth goals of female undergraduates. Subjects selected 10 goals for evaluation along a series of dimensions. When health pursuits alone were examined, hypochondriasis on the Minnesota Multiphasic Personality Inventory was found to correlate directly with goal appraisal dimensions subsumed by an anxiety-absorption factor and inversely with dimensions characterizing rewardingness, thus suggesting a negativity of health goal construal. Somatizers also pursued more health-related projects than did nonsomatizers; nonhealth goal cognition did not relate as strongly to hypochondriasis. Finally, using discriminant function analysis, goal representations were shown to significantly and substantially differentiate somatizers from nonsomatizers.
Salt, sodium chloride or sodium? Content and relationship with chemical, instrumental and sensory attributes in cooked meat products.

PubMed

Kameník, Josef; Saláková, Alena; Vyskočilová, Věra; Pechová, Alena; Haruštiaková, Danka

2017-09-01

The aim of this study was to determine the salt content in selected cooked meat products by the methods of determining the sodium content and the content of chlorides. The resulting data was compared with other chemical, instrumental and sensory parameters of the analysed samples. A total of 133 samples of 5 meat products were tested. The sodium content ranged from 558.0 to 1308.0mgNa/100g. Salt level determined by the two methods strongly correlated and did not differ in any meat product. Intensity of salty taste of the product was independent on its salt content. The salt (sodium) content may be reduced without a negative impact on sensory or instrumental properties of meat products. Copyright © 2017 Elsevier Ltd. All rights reserved.
An event-related brain potential study of visual selective attention to conjunctions of color and shape.

PubMed

Smid, H G; Jakob, A; Heinze, H J

1999-03-01

What cognitive processes underlie event-related brain potential (ERP) effects related to visual multidimensional selective attention and how are these processes organized? We recorded ERPs when participants attended to one conjunction of color, global shape and local shape and ignored other conjunctions of these attributes in three discriminability conditions. Attending to color and shape produced three ERP effects: frontal selection positivity (FSP), central negativity (N2b), and posterior selection negativity (SN). The results suggested that the processes underlying SN and N2b perform independent within-dimension selections, whereas the process underlying the FSP performs hierarchical between-dimension selections. At posterior electrodes, manipulation of discriminability changed the ERPs to the relevant but not to the irrelevant stimuli, suggesting that the SN does not concern the selection process itself but rather a cognitive process initiated after selection is finished. Other findings suggested that selection of multiple visual attributes occurs in parallel.
Pathogen prevalence predicts human cross-cultural variability in individualism/collectivism

PubMed Central

Fincher, Corey L; Thornhill, Randy; Murray, Damian R; Schaller, Mark

2008-01-01

Pathogenic diseases impose selection pressures on the social behaviour of host populations. In humans (Homo sapiens), many psychological phenomena appear to serve an antipathogen defence function. One broad implication is the existence of cross-cultural differences in human cognition and behaviour contingent upon the relative presence of pathogens in the local ecology. We focus specifically on one fundamental cultural variable: differences in individualistic versus collectivist values. We suggest that specific behavioural manifestations of collectivism (e.g. ethnocentrism, conformity) can inhibit the transmission of pathogens; and so we hypothesize that collectivism (compared with individualism) will more often characterize cultures in regions that have historically had higher prevalence of pathogens. Drawing on epidemiological data and the findings of worldwide cross-national surveys of individualism/collectivism, our results support this hypothesis: the regional prevalence of pathogens has a strong positive correlation with cultural indicators of collectivism and a strong negative correlation with individualism. The correlations remain significant even when controlling for potential confounding variables. These results help to explain the origin of a paradigmatic cross-cultural difference, and reveal previously undocumented consequences of pathogenic diseases on the variable nature of human societies. PMID:18302996
Simple, accurate formula for the average bit error probability of multiple-input multiple-output free-space optical links over negative exponential turbulence channels.

PubMed

Peppas, Kostas P; Lazarakis, Fotis; Alexandridis, Antonis; Dangakis, Kostas

2012-08-01

In this Letter we investigate the error performance of multiple-input multiple-output free-space optical communication systems employing intensity modulation/direct detection and operating over strong atmospheric turbulence channels. Atmospheric-induced strong turbulence fading is modeled using the negative exponential distribution. For the considered system, an approximate yet accurate analytical expression for the average bit error probability is derived and an efficient method for its numerical evaluation is proposed. Numerically evaluated and computer simulation results are further provided to demonstrate the validity of the proposed mathematical analysis.
Strongly Emitting Surfaces Unable to Float below Plasma Potential

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campanell, M. D.; Umansky, M. V.

2016-02-25

One important unresolved question in plasma physics concerns the effect of strong electron emission on plasma-surface interactions. Previous papers reported solutions with negative and positive floating potentials relative to the plasma edge. For these two models a very different predictions for particle and energy balance is given. Here we show that the positive potential state is the only possible equilibrium in general. Even if a negative floating potential existed at t=0, the ionization collisions near the surface will force a transition to the positive floating potential state. Moreover, this transition is demonstrated with a new simulation code.
Evolution of the human immunodeficiency virus envelope gene is dominated by purifying selection.

PubMed

Edwards, C T T; Holmes, E C; Pybus, O G; Wilson, D J; Viscidi, R P; Abrams, E J; Phillips, R E; Drummond, A J

2006-11-01

The evolution of the human immunodeficiency virus (HIV-1) during chronic infection involves the rapid, continuous turnover of genetic diversity. However, the role of natural selection, relative to random genetic drift, in governing this process is unclear. We tested a stochastic model of genetic drift using partial envelope sequences sampled longitudinally in 28 infected children. In each case the Bayesian posterior (empirical) distribution of coalescent genealogies was estimated using Markov chain Monte Carlo methods. Posterior predictive simulation was then used to generate a null distribution of genealogies assuming neutrality, with the null and empirical distributions compared using four genealogy-based summary statistics sensitive to nonneutral evolution. Because both null and empirical distributions were generated within a coalescent framework, we were able to explicitly account for the confounding influence of demography. From the distribution of corrected P-values across patients, we conclude that empirical genealogies are more asymmetric than expected if evolution is driven by mutation and genetic drift only, with an excess of low-frequency polymorphisms in the population. This indicates that although drift may still play an important role, natural selection has a strong influence on the evolution of HIV-1 envelope. A negative relationship between effective population size and substitution rate indicates that as the efficacy of selection increases, a smaller proportion of mutations approach fixation in the population. This suggests the presence of deleterious mutations. We therefore conclude that intrahost HIV-1 evolution in envelope is dominated by purifying selection against low-frequency deleterious mutations that do not reach fixation.

Dynamics of Dark-Fly Genome Under Environmental Selections.

PubMed

Izutsu, Minako; Toyoda, Atsushi; Fujiyama, Asao; Agata, Kiyokazu; Fuse, Naoyuki

2015-12-04

Environmental adaptation is one of the most fundamental features of organisms. Modern genome science has identified some genes associated with adaptive traits of organisms, and has provided insights into environmental adaptation and evolution. However, how genes contribute to adaptive traits and how traits are selected under an environment in the course of evolution remain mostly unclear. To approach these issues, we utilize "Dark-fly", a Drosophila melanogaster line maintained in constant dark conditions for more than 60 years. Our previous analysis identified 220,000 single nucleotide polymorphisms (SNPs) in the Dark-fly genome, but did not clarify which SNPs of Dark-fly are truly adaptive for living in the dark. We found here that Dark-fly dominated over the wild-type fly in a mixed population under dark conditions, and based on this domination we designed an experiment for genome reselection to identify adaptive genes of Dark-fly. For this experiment, large mixed populations of Dark-fly and the wild-type fly were maintained in light conditions or in dark conditions, and the frequencies of Dark-fly SNPs were compared between these populations across the whole genome. We thereby detected condition-dependent selections toward approximately 6% of the genome. In addition, we observed the time-course trajectory of SNP frequency in the mixed populations through generations 0, 22, and 49, which resulted in notable categorization of the selected SNPs into three types with different combinations of positive and negative selections. Our data provided a list of about 100 strong candidate genes associated with the adaptive traits of Dark-fly. Copyright © 2016 Izutsu et al.
Dynamics of Dark-Fly Genome Under Environmental Selections

PubMed Central

Izutsu, Minako; Toyoda, Atsushi; Fujiyama, Asao; Agata, Kiyokazu; Fuse, Naoyuki

2015-01-01

Environmental adaptation is one of the most fundamental features of organisms. Modern genome science has identified some genes associated with adaptive traits of organisms, and has provided insights into environmental adaptation and evolution. However, how genes contribute to adaptive traits and how traits are selected under an environment in the course of evolution remain mostly unclear. To approach these issues, we utilize “Dark-fly”, a Drosophila melanogaster line maintained in constant dark conditions for more than 60 years. Our previous analysis identified 220,000 single nucleotide polymorphisms (SNPs) in the Dark-fly genome, but did not clarify which SNPs of Dark-fly are truly adaptive for living in the dark. We found here that Dark-fly dominated over the wild-type fly in a mixed population under dark conditions, and based on this domination we designed an experiment for genome reselection to identify adaptive genes of Dark-fly. For this experiment, large mixed populations of Dark-fly and the wild-type fly were maintained in light conditions or in dark conditions, and the frequencies of Dark-fly SNPs were compared between these populations across the whole genome. We thereby detected condition-dependent selections toward approximately 6% of the genome. In addition, we observed the time-course trajectory of SNP frequency in the mixed populations through generations 0, 22, and 49, which resulted in notable categorization of the selected SNPs into three types with different combinations of positive and negative selections. Our data provided a list of about 100 strong candidate genes associated with the adaptive traits of Dark-fly. PMID:26637434
LOFAR-Boötes: properties of high- and low-excitation radio galaxies at 0.5 < z < 2.0

NASA Astrophysics Data System (ADS)

Williams, W. L.; Calistro Rivera, G.; Best, P. N.; Hardcastle, M. J.; Röttgering, H. J. A.; Duncan, K. J.; de Gasperin, F.; Jarvis, M. J.; Miley, G. K.; Mahony, E. K.; Morabito, L. K.; Nisbet, D. M.; Prandoni, I.; Smith, D. J. B.; Tasse, C.; White, G. J.

2018-04-01

This paper presents a study of the redshift evolution of radio-loud active galactic nuclei (AGN) as a function of the properties of their galaxy hosts in the Boötes field. To achieve this we match low-frequency radio sources from deep 150-MHz LOFAR (LOw Frequency ARray) observations to an I-band-selected catalogue of galaxies, for which we have derived photometric redshifts, stellar masses, and rest-frame colours. We present spectral energy distribution (SED) fitting to determine the mid-infrared AGN contribution for the radio sources and use this information to classify them as high- versus low-excitation radio galaxies (HERGs and LERGs) or star-forming galaxies. Based on these classifications, we construct luminosity functions for the separate redshift ranges going out to z = 2. From the matched radio-optical catalogues, we select a sub-sample of 624 high power (P150 MHz > 1025 W Hz-1) radio sources between 0.5 ≤ z < 2. For this sample, we study the fraction of galaxies hosting HERGs and LERGs as a function of stellar mass and host galaxy colour. The fraction of HERGs increases with redshift, as does the fraction of sources in galaxies with lower stellar masses. We find that the fraction of galaxies that host LERGs is a strong function of stellar mass as it is in the local Universe. This, combined with the strong negative evolution of the LERG luminosity functions over this redshift range, is consistent with LERGs being fuelled by hot gas in quiescent galaxies.
Finding strong lenses in CFHTLS using convolutional neural networks

NASA Astrophysics Data System (ADS)

Jacobs, C.; Glazebrook, K.; Collett, T.; More, A.; McCarthy, C.

2017-10-01

We train and apply convolutional neural networks, a machine learning technique developed to learn from and classify image data, to Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) imaging for the identification of potential strong lensing systems. An ensemble of four convolutional neural networks was trained on images of simulated galaxy-galaxy lenses. The training sets consisted of a total of 62 406 simulated lenses and 64 673 non-lens negative examples generated with two different methodologies. An ensemble of trained networks was applied to all of the 171 deg2 of the CFHTLS wide field image data, identifying 18 861 candidates including 63 known and 139 other potential lens candidates. A second search of 1.4 million early-type galaxies selected from the survey catalogue as potential deflectors, identified 2465 candidates including 117 previously known lens candidates, 29 confirmed lenses/high-quality lens candidates, 266 novel probable or potential lenses and 2097 candidates we classify as false positives. For the catalogue-based search we estimate a completeness of 21-28 per cent with respect to detectable lenses and a purity of 15 per cent, with a false-positive rate of 1 in 671 images tested. We predict a human astronomer reviewing candidates produced by the system would identify 20 probable lenses and 100 possible lenses per hour in a sample selected by the robot. Convolutional neural networks are therefore a promising tool for use in the search for lenses in current and forthcoming surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope.
Characterizing Lithospheric Thickness in Australia using Ps and Sp Scattered Waves

NASA Astrophysics Data System (ADS)

Ford, H. A.; Fischer, K. M.; Rychert, C. A.

2008-12-01

The purpose of this study is to constrain the morphology of the lithosphere-asthenosphere boundary throughout Australia using scattered waves. Prior surface wave studies have shown a correlation between lithospheric thickness and the three primary geologic provinces of Australia, with the shallowest lithosphere located beneath the Phanerozoic province to the east, and the thicker lithosphere located beneath the Proterozoic and Archean regions. To determine lithospheric thickness, waveform data from twenty permanent broadband stations spanning mainland Australia and the island of Tasmania were analyzed using Ps and Sp migration techniques. Waveform selection for each station was based on epicentral distance (35° to 80° for Ps and 55° to 80° for Sp), and event depth (no greater than 300 km for Sp). For both Ps and Sp a simultaneous deconvolution was performed on the data for each of the twenty stations, and the resulting receiver function for each station was migrated to depth. Data were binned with epicentral distance to differentiate direct discontinuity phases from crustal reverberations (for Ps) and other teleseismic arrivals (for Sp). Early results in both Ps and Sp show a clear Moho discontinuity at most stations in addition to sharp, strong crustal reverberations seen in many of the Ps images. In the eastern Phanerozoic province, a strong negative phase at 100-105 km is evident in Ps for stations CAN and EIDS. The negative phase lies within a depth range that corresponds to the negative velocity gradient between fast lithosphere and slow asthenosphere imaged by surface waves. We therefore think that it is the lithosphere- asthenosphere boundary. On the island of Tasmania, a negative phase at 70-75 km in Ps images at stations TAU and MOO also appears to be the lithosphere-asthenosphere boundary. In the Proterozoic and Archean regions of the Australian continent, initial results for both Ps and Sp migration indicate clear crustal phases, but significantly more complicated signals at mantle depths. However, at some stations along the southern edge of the thick sub-cratonic lithosphere (previously imaged by surface waves) phases exist which may represent a lithosphere-asthenosphere boundary at depths of 110-115 km. Constraining the relationship of lithospheric thickness to the age and tectonic history of the overlying crust in Australia is important for better understanding the long term evolution of the continent.
Mode Selection Rules for a Two-Delay System with Positive and Negative Feedback Loops

NASA Astrophysics Data System (ADS)

Takahashi, Kin'ya; Kobayashi, Taizo

2018-04-01

The mode selection rules for a two-delay system, which has negative feedback with a short delay time t1 and positive feedback with a long delay time t2, are studied numerically and theoretically. We find two types of mode selection rules depending on the strength of the negative feedback. When the strength of the negative feedback |α1| (α1 < 0) is sufficiently small compared with that of the positive feedback α2 (> 0), 2m + 1-th harmonic oscillation is well sustained in a neighborhood of t1/t2 = even/odd, i.e., relevant condition. In a neighborhood of the irrelevant condition given by t1/t2 = odd/even or t1/t2 = odd/odd, higher harmonic oscillations are observed. However, if |α1| is slightly less than α2, a different mode selection rule works, where the condition t1/t2 = odd/even is relevant and the conditions t1/t2 = odd/odd and t1/t2 = even/odd are irrelevant. These mode selection rules are different from the mode selection rule of the normal two-delay system with two positive feedback loops, where t1/t2 = odd/odd is relevant and the others are irrelevant. The two types of mode selection rules are induced by individually different mechanisms controlling the Hopf bifurcation, i.e., the Hopf bifurcation controlled by the "boosted bifurcation process" and by the "anomalous bifurcation process", which occur for |α1| below and above the threshold value αth, respectively.
What explains rare and conspicuous colours in a snail? A test of time-series data against models of drift, migration or selection.

PubMed

Johannesson, K; Butlin, R K

2017-01-01

It is intriguing that conspicuous colour morphs of a prey species may be maintained at low frequencies alongside cryptic morphs. Negative frequency-dependent selection by predators using search images ('apostatic selection') is often suggested without rejecting alternative explanations. Using a maximum likelihood approach we fitted predictions from models of genetic drift, migration, constant selection, heterozygote advantage or negative frequency-dependent selection to time-series data of colour frequencies in isolated populations of a marine snail (Littorina saxatilis), re-established with perturbed colour morph frequencies and followed for >20 generations. Snails of conspicuous colours (white, red, banded) are naturally rare in the study area (usually <10%) but frequencies were manipulated to levels of ~50% (one colour per population) in 8 populations at the start of the experiment in 1992. In 2013, frequencies had declined to ~15-45%. Drift alone could not explain these changes. Migration could not be rejected in any population, but required rates much higher than those recorded. Directional selection was rejected in three populations in favour of balancing selection. Heterozygote advantage and negative frequency-dependent selection could not be distinguished statistically, although overall the results favoured the latter. Populations varied idiosyncratically as mild or variable colour selection (3-11%) interacted with demographic stochasticity, and the overall conclusion was that multiple mechanisms may contribute to maintaining the polymorphisms.
40 CFR 798.5275 - Sex-linked recessive lethal test in drosophila melanogaster.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Control groups—(i) Concurrent controls. Concurrent positive and negative (vehicle) controls shall be... the negative (vehicle) control group shall be determined by the availability of appropriate laboratory... the appropriate control group will strongly influence the number of treated chromosomes that must be...
40 CFR 798.5275 - Sex-linked recessive lethal test in drosophila melanogaster.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Control groups—(i) Concurrent controls. Concurrent positive and negative (vehicle) controls shall be... the negative (vehicle) control group shall be determined by the availability of appropriate laboratory... the appropriate control group will strongly influence the number of treated chromosomes that must be...
40 CFR 798.5275 - Sex-linked recessive lethal test in drosophila melanogaster.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Control groups—(i) Concurrent controls. Concurrent positive and negative (vehicle) controls shall be... the negative (vehicle) control group shall be determined by the availability of appropriate laboratory... the appropriate control group will strongly influence the number of treated chromosomes that must be...
40 CFR 798.5275 - Sex-linked recessive lethal test in drosophila melanogaster.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Control groups—(i) Concurrent controls. Concurrent positive and negative (vehicle) controls shall be... the negative (vehicle) control group shall be determined by the availability of appropriate laboratory... the appropriate control group will strongly influence the number of treated chromosomes that must be...
40 CFR 798.5275 - Sex-linked recessive lethal test in drosophila melanogaster.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Control groups—(i) Concurrent controls. Concurrent positive and negative (vehicle) controls shall be... the negative (vehicle) control group shall be determined by the availability of appropriate laboratory... the appropriate control group will strongly influence the number of treated chromosomes that must be...
Behavioral and neuronal determinants of negative reciprocity in the ultimatum game.

PubMed

Kaltwasser, Laura; Hildebrandt, Andrea; Wilhelm, Oliver; Sommer, Werner

2016-10-01

The rejection of unfair offers in the ultimatum game (UG) indicates negative reciprocity. The model of strong reciprocity claims that negative reciprocity reflects prosociality because the rejecting individual is sacrificing resources in order to punish unfair behavior. However, a recent study found that the rejection rate of unfair offers is linked to assertiveness (status defense model). To pursue the question what drives negative reciprocity, the present study investigated individual differences in the rejection of unfair offers along with their behavioral and neuronal determinants. We measured fairness preferences and event-related potentials (ERP) in 200 healthy participants playing a computerized version of the UG with pictures of unfair and fair proposers. Structural equation modeling (SEM) on the behavioral data corroborated both the strong reciprocity and the status defense models of human cooperation: Not only more prosocial but also more assertive individuals were more likely to show negative reciprocity by rejecting unfair offers. Experimental ERP results confirmed the feedback negativity (FN) as a neural signature of fairness processing. Multilevel SEM of brain-behavior relationships revealed that negative reciprocity was significantly associated with individual differences in FN amplitudes in response to proposers. Our results confirm stable individual differences in fairness processing at the behavioral and neuronal level. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.
CLAVATA1 Dominant-Negative Alleles Reveal Functional Overlap between Multiple Receptor Kinases That Regulate Meristem and Organ Development

PubMed Central

Diévart, Anne; Dalal, Monica; Tax, Frans E.; Lacey, Alexzandria D.; Huttly, Alison; Li, Jianming; Clark, Steven E.

2003-01-01

The CLAVATA1 (CLV1) receptor kinase controls stem cell number and differentiation at the Arabidopsis shoot and flower meristems. Other components of the CLV1 signaling pathway include the secreted putative ligand CLV3 and the receptor-like protein CLV2. We report evidence indicating that all intermediate and strong clv1 alleles are dominant negative and likely interfere with the activity of unknown receptor kinase(s) that have functional overlap with CLV1. clv1 dominant-negative alleles show major differences from dominant-negative alleles characterized to date in animal receptor kinase signaling systems, including the lack of a dominant-negative effect of kinase domain truncation and the ability of missense mutations in the extracellular domain to act in a dominant-negative manner. We analyzed chimeric receptor kinases by fusing CLV1 and BRASSINOSTEROID INSENSITIVE1 (BRI1) coding sequences and expressing these in clv1 null backgrounds. Constructs containing the CLV1 extracellular domain and the BRI1 kinase domain were strongly dominant negative in the regulation of meristem development. Furthermore, we show that CLV1 expressed within the pedicel can partially replace the function of the ERECTA receptor kinase. We propose the presence of multiple receptors that regulate meristem development in a functionally related manner whose interactions are driven by the extracellular domains and whose activation requires the kinase domain. PMID:12724544
Climate change and evolution: disentangling environmental and genetic responses.

PubMed

Gienapp, P; Teplitsky, C; Alho, J S; Mills, J A; Merilä, J

2008-01-01

Rapid climate change is likely to impose strong selection pressures on traits important for fitness, and therefore, microevolution in response to climate-mediated selection is potentially an important mechanism mitigating negative consequences of climate change. We reviewed the empirical evidence for recent microevolutionary responses to climate change in longitudinal studies emphasizing the following three perspectives emerging from the published data. First, although signatures of climate change are clearly visible in many ecological processes, similar examples of microevolutionary responses in literature are in fact very rare. Second, the quality of evidence for microevolutionary responses to climate change is far from satisfactory as the documented responses are often - if not typically - based on nongenetic data. We reinforce the view that it is as important to make the distinction between genetic (evolutionary) and phenotypic (includes a nongenetic, plastic component) responses clear, as it is to understand the relative roles of plasticity and genetics in adaptation to climate change. Third, in order to illustrate the difficulties and their potential ubiquity in detection of microevolution in response to natural selection, we reviewed the quantitative genetic studies on microevolutionary responses to natural selection in the context of long-term studies of vertebrates. The available evidence points to the overall conclusion that many responses perceived as adaptations to changing environmental conditions could be environmentally induced plastic responses rather than microevolutionary adaptations. Hence, clear-cut evidence indicating a significant role for evolutionary adaptation to ongoing climate warming is conspicuously scarce.
Repeated landscape-scale treatments following fire suppress a non-native annual grass and promote recovery of native perennial vegetation

USGS Publications Warehouse

Munson, Seth M.; Long, A. Lexine; Decker, Cheryl E.; Johnson, Katie A.; Walsh, Kathleen; Miller, Mark E.

2015-01-01

Invasive non-native species pose a large threat to restoration efforts following large-scale disturbances. Bromus tectorum (cheatgrass) is a non-native annual grass in the western U.S. that both spreads quickly following fire and accelerates the fire cycle. Herbicide and seeding applications are common restoration practices to break the positive fire-invasion feedback loop and recover native perennial species, but their interactive effects have infrequently been tested at the landscape-scale and repeated in time to encourage long-lasting effects. We determined the efficacy of repeated post-fire application of the herbicide imazapic and seeding treatments to suppressBromus abundance and promote perennial vegetation recovery. We found that the selective herbicide reduced Bromus cover by ~30 % and density by >50 % across our study sites, but had a strong initial negative effect on seeded species. The most effective treatment to promote perennial seeded species cover was seeding them alone followed by herbicide application 3 years later when the seeded species had established. The efficacy of the treatments was strongly influenced by water availability, as precipitation positively affected the density and cover of Bromus; soil texture and aspect secondarily influenced Bromus abundance and seeded species cover by modifying water retention in this semi-arid region. Warmer temperatures positively affected the non-native annual grass in the cool-season, but negatively affected seeded perennial species in the warm-season, suggesting an important role of seasonality in a region projected to experience large increases in warming in the future. Our results highlight the importance of environmental interactions and repeated treatments in influencing restoration outcomes at the landscape-scale.
Multimodal analysis of pretreated biomass species highlights generic markers of lignocellulose recalcitrance.

PubMed

Herbaut, Mickaël; Zoghlami, Aya; Habrant, Anouck; Falourd, Xavier; Foucat, Loïc; Chabbert, Brigitte; Paës, Gabriel

2018-01-01

Biomass recalcitrance to enzymatic hydrolysis has been assigned to several structural and chemical factors. However, their relative importance remains challenging to evaluate. Three representative biomass species (wheat straw, poplar and miscanthus) were submitted to four standard pretreatments (dilute acid, hot water, ionic liquid and sodium chlorite) in order to generate a set of contrasted samples. A large array of techniques, including wet chemistry analysis, porosity measurements using NMR spectroscopy, electron and fluorescence microscopy, were used in order to determine possible generic factors of biomass recalcitrance. The pretreatment conditions selected allowed obtaining samples displaying different susceptibility to enzymatic hydrolysis (from 3 up to 98% of the initial glucose content released after 96 h of saccharification). Generic correlation coefficients were calculated between the measured chemical and structural features and the final saccharification rates. Increases in porosity displayed overall strong positive correlations with saccharification efficiency, but different porosity ranges were concerned depending on the considered biomass. Lignin-related factors displayed highly negative coefficients for all biomasses. Lignin content, which is likely involved in the correlations observed for porosity, was less detrimental to enzymatic hydrolysis than lignin composition. Lignin influence was highlighted by the strong negative correlation with fluorescence intensity which mainly originates from monolignols in mature tissues. Our results provide a better understanding of the factors responsible for biomass recalcitrance that can reasonably be considered as generic. The correlations with specific porosity ranges are biomass species-dependent, meaning that enzymes cocktails with fitted enzyme size are likely to be needed to optimise saccharification depending on the biomass origin. Lignin composition, which probably influences its structure, is the most important parameter to overcome to enhance enzymes access to the polysaccharides. Accordingly, fluorescence intensity was found to be a rapid and simple method to assess recalcitrance after pretreatment.
[Assessment of the patient-safety culture in a healthcare district].

PubMed

Pozo Muñoz, F; Padilla Marín, V

2013-01-01

1) To describe the frequency of positive attitudes and behaviours, in terms of patient safety, among the healthcare providers working in a healthcare district; 2) to determine whether the level of safety-related culture differs from other studies; and 3) to analyse negatively valued dimensions, and to establish areas for their improvement. A descriptive, cross-sectional study based on the results of an evaluation of the safety-related culture was conducted on a randomly selected sample of 247 healthcare providers, by using the Spanish adaptation of the Hospital Survey on Patient Safety Culture (HSOPSC) designed by the Agency for Healthcare Research and Quality (AHRQ), as the evaluation tool. Positive and negative responses were analysed, as well as the global score. Results were compared with international and national results. A total of 176 completed survey questionnaires were analysed (response rate: 71.26%); 50% of responders described the safety climate as very good, 37% as acceptable, and 7% as excellent. Strong points were: «Teamwork within the units» (80.82%) and «Supervisor/manager expectations and actions» (80.54%). Dimensions identified for potential improvement included: «Staffing» (37.93%), «Non-punitive response to error» (41.67%), and «Frequency of event reporting» (49.05%). Strong and weak points were identified in the safety-related culture of the healthcare district studied, together with potential improvement areas. Benchmarking at the international level showed that our safety-related culture was within the average of hospitals, while at the national level, our results were above the average of hospitals. Copyright © 2013 SECA. Published by Elsevier Espana. All rights reserved.
Importance of intra- and interspecific plant interactions for the phytomanagement of semiarid mine tailings using the tree species Pinus halepensis.

PubMed

Martinez-Oró, Duli; Parraga-Aguado, Isabel; Querejeta, Jose Ignacio; Conesa, Héctor M

2017-11-01

The objective of this work was to evaluate the effects of plant interactions (intra- and interspecific) on the growth and metal(loid) uptake of the tree species Pinus halepensis to determine its suitability for the phytomanagement of semiarid mine tailings. The pioneer tailings colonizer grass Piptatherum miliaceum was selected for assessing interspecific interactions. The experiment was conducted following a pot experimental design employing mine tailings soil. Pots containing single individuals of P. halepensis or P. miliaceum and pots containing combinations with pines (two pines per pot, or one pine and one grass per pot) were used. The analyses included the determination of plant biomass, foliar element status and stable isotope composition, metal(loid) uptake and its translocation to different plant organs. P. halepensis strongly favoured the growth of P. miliaceum by increasing 9-fold the latter's biomass and alleviating its P limitation. In this interspecific treatment P. halepensis showed a strong N limitation (N/P = 7), which negatively affected its growth, (to about half the biomass of that obtained for the other treatments) and exhibited a significant increase in some metals translocation (especially Cd) into aerial parts. Interestingly, P. miliaceum showed a decrease in the root to leaves translocation factor for most of metals when growing together with pines. The effects of the intraespecific combination on growth and metal uptake in P. halepensis were less relevant than those obtained for the interspecific one. Further research should be focused on testing the behaviour of plant co-cultures under the addition of N or P amendments which could alleviate the negative effects of plant competition. Copyright © 2017 Elsevier Ltd. All rights reserved.
Selection based on the size of the black tie of the great tit may be reversed in urban habitats.

PubMed

Senar, Juan Carlos; Conroy, Michael J; Quesada, Javier; Mateos-Gonzalez, Fernando

2014-07-01

A standard approach to model how selection shapes phenotypic traits is the analysis of capture-recapture data relating trait variation to survival. Divergent selection, however, has never been analyzed by the capture-recapture approach. Most reported examples of differences between urban and nonurban animals reflect behavioral plasticity rather than divergent selection. The aim of this paper was to use a capture-recapture approach to test the hypothesis that divergent selection can also drive local adaptation in urban habitats. We focused on the size of the black breast stripe (i.e., tie width) of the great tit (Parus major), a sexual ornament used in mate choice. Urban great tits display smaller tie sizes than forest birds. Because tie size is mostly genetically determined, it could potentially respond to selection. We analyzed capture/recapture data of male great tits in Barcelona city (N = 171) and in a nearby (7 km) forest (N = 324) from 1992 to 2008 using MARK. When modelling recapture rate, we found it to be strongly influenced by tie width, so that both for urban and forest habitats, birds with smaller ties were more trap-shy and more cautious than their larger tied counterparts. When modelling survival, we found that survival prospects in forest great tits increased the larger their tie width (i.e., directional positive selection), but the reverse was found for urban birds, with individuals displaying smaller ties showing higher survival (i.e., directional negative selection). As melanin-based tie size seems to be related to personality, and both are heritable, results may be explained by cautious personalities being favored in urban environments. More importantly, our results show that divergent selection can be an important mechanism in local adaptation to urban habitats and that capture-recapture is a powerful tool to test it.

Strength of selection pressure is an important parameter contributing to the complexity of antibiotic resistance evolution.

PubMed

Oz, Tugce; Guvenek, Aysegul; Yildiz, Sadik; Karaboga, Enes; Tamer, Yusuf Talha; Mumcuyan, Nirva; Ozan, Vedat Burak; Senturk, Gizem Hazal; Cokol, Murat; Yeh, Pamela; Toprak, Erdal

2014-09-01

Revealing the genetic changes responsible for antibiotic resistance can be critical for developing novel antibiotic therapies. However, systematic studies correlating genotype to phenotype in the context of antibiotic resistance have been missing. In order to fill in this gap, we evolved 88 isogenic Escherichia coli populations against 22 antibiotics for 3 weeks. For every drug, two populations were evolved under strong selection and two populations were evolved under mild selection. By quantifying evolved populations' resistances against all 22 drugs, we constructed two separate cross-resistance networks for strongly and mildly selected populations. Subsequently, we sequenced representative colonies isolated from evolved populations for revealing the genetic basis for novel phenotypes. Bacterial populations that evolved resistance against antibiotics under strong selection acquired high levels of cross-resistance against several antibiotics, whereas other bacterial populations evolved under milder selection acquired relatively weaker cross-resistance. In addition, we found that strongly selected strains against aminoglycosides became more susceptible to five other drug classes compared with their wild-type ancestor as a result of a point mutation on TrkH, an ion transporter protein. Our findings suggest that selection strength is an important parameter contributing to the complexity of antibiotic resistance problem and use of high doses of antibiotics to clear infections has the potential to promote increase of cross-resistance in clinics. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.
Understanding heterogeneity in borderline personality disorder: differences in affective reactivity explained by the traits of dependency and self-criticism.

PubMed

Kopala-Sibley, Daniel C; Zuroff, David C; Russell, Jennifer J; Moskowitz, D S; Paris, Joel

2012-08-01

This study examined whether the personality traits of self-criticism and dependency respectively moderated the effects of perceived inferiority and emotional insecurity on negative affect during interpersonal interactions in individuals with borderline personality disorder (BPD). A sample of 38 patients with BPD and matched community comparison participants completed event-contingent record forms after each significant interaction for a 20-day period. Multilevel models showed that, controlling for baseline levels of depressive symptoms and neuroticism, as well as lagged negative affect, event-level elevations in perceived inferiority and emotional insecurity were related to more negative affect in both groups. Event-level perceived inferiority was more strongly associated with negative affect in patients with BPD who reported higher levels of self-criticism, while event-level perceived emotional insecurity was more strongly associated with negative affect in patients with BPD who reported higher levels of dependency. No significant interactions emerged for the comparison group. These findings further our understanding of differences among patients with BPD and support the application of personality-vulnerability or diathesis-stress models in predicting negative affect in BPD. Results have implications for the design of therapies for patients with BPD. PsycINFO Database Record (c) 2012 APA, all rights reserved.
Types of work-family interface: well-being correlates of negative and positive spillover between work and family.

PubMed

Kinnunen, Ulla; Feldt, Taru; Geurts, Sabine; Pulkkinen, Lea

2006-04-01

The aim of the present study was to test the structure of the work-family interface measure, which was intended to take into account both the positive and negative spillover between work and family demands in both directions. In addition, the links among the types of work-family spillover and the subjects' general and domain-specific well-being were examined. The sample (n = 202) consisted of Finnish employees, aged 42, who had a spouse/partner. Confirmatory factor analyses indicated that a four-factor model, including negative work-to-family spillover, negative family-to-work spillover, positive work-to-family spillover, and positive family-to-work spillover, was superior compared to the other factor models examined. Path analysis showed, as hypothesized, that the negative work-to-family spillover was most strongly related to low well-being at work (job exhaustion) and next strongly to low general well-being (psychological distress), whereas the negative family-to-work spillover was associated with low well-being in the domain of family (marital dissatisfaction). Positive work-to-family spillover was positively related both to well-being at work and general well-being. Inconsistent with our expectations, positive family-to-work spillover was not directly related to any of the well-being indicators examined.
Negative plant-soil feedback predicts tree-species relative abundance in a tropical forest.

PubMed

Mangan, Scott A; Schnitzer, Stefan A; Herre, Edward A; Mack, Keenan M L; Valencia, Mariana C; Sanchez, Evelyn I; Bever, James D

2010-08-05

The accumulation of species-specific enemies around adults is hypothesized to maintain plant diversity by limiting the recruitment of conspecific seedlings relative to heterospecific seedlings. Although previous studies in forested ecosystems have documented patterns consistent with the process of negative feedback, these studies are unable to address which classes of enemies (for example, pathogens, invertebrates, mammals) exhibit species-specific effects strong enough to generate negative feedback, and whether negative feedback at the level of the individual tree is sufficient to influence community-wide forest composition. Here we use fully reciprocal shade-house and field experiments to test whether the performance of conspecific tree seedlings (relative to heterospecific seedlings) is reduced when grown in the presence of enemies associated with adult trees. Both experiments provide strong evidence for negative plant-soil feedback mediated by soil biota. In contrast, above-ground enemies (mammals, foliar herbivores and foliar pathogens) contributed little to negative feedback observed in the field. In both experiments, we found that tree species that showed stronger negative feedback were less common as adults in the forest community, indicating that susceptibility to soil biota may determine species relative abundance in these tropical forests. Finally, our simulation models confirm that the strength of local negative feedback that we measured is sufficient to produce the observed community-wide patterns in tree-species relative abundance. Our findings indicate that plant-soil feedback is an important mechanism that can maintain species diversity and explain patterns of tree-species relative abundance in tropical forests.
Systems modeling accurately predicts responses to genotoxic agents and their synergism with BCL-2 inhibitors in triple negative breast cancer cells.

PubMed

Lucantoni, Federico; Lindner, Andreas U; O'Donovan, Norma; Düssmann, Heiko; Prehn, Jochen H M

2018-01-19

Triple negative breast cancer (TNBC) is an aggressive form of breast cancer which accounts for 15-20% of this disease and is currently treated with genotoxic chemotherapy. The BCL2 (B-cell lymphoma 2) family of proteins controls the process of mitochondrial outer membrane permeabilization (MOMP), which is required for the activation of the mitochondrial apoptosis pathway in response to genotoxic agents. We previously developed a deterministic systems model of BCL2 protein interactions, DR_MOMP that calculates the sensitivity of cells to undergo mitochondrial apoptosis. Here we determined whether DR_MOMP predicts responses of TNBC cells to genotoxic agents and the re-sensitization of resistant cells by BCL2 inhibitors. Using absolute protein levels of BAX, BAK, BCL2, BCL(X)L and MCL1 as input for DR_MOMP, we found a strong correlation between model predictions and responses of a panel of TNBC cells to 24 and 48 h cisplatin (R 2 = 0.96 and 0.95, respectively) and paclitaxel treatments (R 2 = 0.94 and 0.95, respectively). This outperformed single protein correlations (best performer BCL(X)L with R 2 of 0.69 and 0.50 for cisplatin and paclitaxel treatments, respectively) and BCL2 proteins ratio (R 2 of 0.50 for cisplatin and 0.49 for paclitaxel). Next we performed synergy studies using the BCL2 selective antagonist Venetoclax /ABT199, the BCL(X)L selective antagonist WEHI-539, or the MCL1 selective antagonist A-1210477 in combination with cisplatin. In silico predictions by DR_MOMP revealed substantial differences in treatment responses of BCL(X)L, BCL2 or MCL1 inhibitors combinations with cisplatin that were successfully validated in cell lines. Our findings provide evidence that DR_MOMP predicts responses of TNBC cells to genotoxic therapy, and can aid in the choice of the optimal BCL2 protein antagonist for combination treatments of resistant cells.
Consistent Selection towards Low Activity Phenotypes When Catchability Depends on Encounters among Human Predators and Fish

PubMed Central

Alós, Josep; Palmer, Miquel; Arlinghaus, Robert

2012-01-01

Together with life-history and underlying physiology, the behavioural variability among fish is one of the three main trait axes that determines the vulnerability to fishing. However, there are only a few studies that have systematically investigated the strength and direction of selection acting on behavioural traits. Using in situ fish behaviour revealed by telemetry techniques as input, we developed an individual-based model (IBM) that simulated the Lagrangian trajectory of prey (fish) moving within a confined home range (HR). Fishers exhibiting various prototypical fishing styles targeted these fish in the model. We initially hypothesised that more active and more explorative individuals would be systematically removed under all fished conditions, in turn creating negative selection differentials on low activity phenotypes and maybe on small HR. Our results partly supported these general predictions. Standardised selection differentials were, on average, more negative on HR than on activity. However, in many simulation runs, positive selection pressures on HR were also identified, which resulted from the stochastic properties of the fishes’ movement and its interaction with the human predator. In contrast, there was a consistent negative selection on activity under all types of fishing styles. Therefore, in situations where catchability depends on spatial encounters between human predators and fish, we would predict a consistent selection towards low activity phenotypes and have less faith in the direction of the selection on HR size. Our study is the first theoretical investigation on the direction of fishery-induced selection of behaviour using passive fishing gears. The few empirical studies where catchability of fish was measured in relation to passive fishing techniques, such as gill-nets, traps or recreational fishing, support our predictions that fish in highly exploited situations are, on average, characterised by low swimming activity, stemming, in part, from negative selection on swimming activity. PMID:23110164
Location negative priming effects in children with developmental dyslexia: An event-related potential study.

PubMed

Ma, Yujun; Wang, Enguo; Yuan, Tian; Zhao, Guo Xiang

2016-08-01

As the reading process is inseparable from working memory, inhibition, and other higher cognitive processes, the deep cognitive processing defects that are associated with dyslexia may be due to defective distraction inhibition systems. In this study, we used event-related potential technology to explore the source of negative priming effects in children with developmental dyslexia and in a group of healthy children for comparison. We found that the changes in the average response times in the negative priming and control conditions were consistent across the two groups, while the negative priming effects differed significantly between the groups. The magnitude of the negative priming effect was significantly different between the two groups, with the magnitude being significantly higher in the control group than it was in the developmental dyslexia group. These results indicate that there are deficits in distraction inhibition in children with developmental dyslexia. In terms of the time course of processing, inhibition deficits in the dyslexia group appeared during early-stage cognition selection and lasted through the response selection phase. Regarding the cerebral cortex locations, early-stage cognition selection was mainly located in the parietal region, while late-stage response selection was mainly located in the frontal and central regions. The results of our study may help further our understanding of the intrinsic causes of developmental dyslexia. Copyright © 2016 Elsevier Ltd. All rights reserved.
A Cross-National Investigation of Student Intentions to Pursue a Sales Career

ERIC Educational Resources Information Center

Karakaya, Fahri; Quigley, Charles; Bingham, Frank

2011-01-01

Previous studies related to student selection of a sales career indicate that their perception of sales as a career is generally negative. Numerous reasons have been offered for this negative view, including negative perceptions of attributes associated with sales jobs and salespeople. This study examines the perceptions of negative and positive…
Population genetics inference for longitudinally-sampled mutants under strong selection.

PubMed

Lacerda, Miguel; Seoighe, Cathal

2014-11-01

Longitudinal allele frequency data are becoming increasingly prevalent. Such samples permit statistical inference of the population genetics parameters that influence the fate of mutant variants. To infer these parameters by maximum likelihood, the mutant frequency is often assumed to evolve according to the Wright-Fisher model. For computational reasons, this discrete model is commonly approximated by a diffusion process that requires the assumption that the forces of natural selection and mutation are weak. This assumption is not always appropriate. For example, mutations that impart drug resistance in pathogens may evolve under strong selective pressure. Here, we present an alternative approximation to the mutant-frequency distribution that does not make any assumptions about the magnitude of selection or mutation and is much more computationally efficient than the standard diffusion approximation. Simulation studies are used to compare the performance of our method to that of the Wright-Fisher and Gaussian diffusion approximations. For large populations, our method is found to provide a much better approximation to the mutant-frequency distribution when selection is strong, while all three methods perform comparably when selection is weak. Importantly, maximum-likelihood estimates of the selection coefficient are severely attenuated when selection is strong under the two diffusion models, but not when our method is used. This is further demonstrated with an application to mutant-frequency data from an experimental study of bacteriophage evolution. We therefore recommend our method for estimating the selection coefficient when the effective population size is too large to utilize the discrete Wright-Fisher model. Copyright © 2014 by the Genetics Society of America.
Protein Kinase A Regulates Constitutive Expression of Small Heat-Shock Genes in an Msn2/4p-Independent and Hsf1p-Dependent Manner in Saccharomyces cerevisiae

PubMed Central

Ferguson, Scott B.; Anderson, Erik S.; Harshaw, Robyn B.; Thate, Tim; Craig, Nancy L.; Nelson, Hillary C. M.

2005-01-01

Hsf1p, the heat-shock transcription factor from Saccharomyces cerevisiae, has a low level of constitutive transcriptional activity and is kept in this state through negative regulation. In an effort to understand this negative regulation, we developed a novel genetic selection that detects altered expression from the HSP26 promoter. Using this reporter strain, we identified mutations and dosage compensators in the Ras/cAMP signaling pathway that decrease cAMP levels and increase expression from the HSP26 promoter. In yeast, low cAMP levels reduce the catalytic activity of the cAMP-dependent kinase PKA. Previous studies had proposed that the stress response transcription factors Msn2p/4p, but not Hsf1p, are repressed by PKA. However, we found that reduction or elimination of PKA activity strongly derepresses transcription of the small heat-shock genes HSP26 and HSP12, even in the absence of MSN2/4. In a strain deleted for MSN2/4 and the PKA catalytic subunits, expression of HSP12 and HSP26 depends on HSF1 expression. Our findings indicate that Hsf1p functions downstream of PKA and suggest that PKA might be involved in negative regulation of Hsf1p activity. These results represent a major change in our understanding of how PKA signaling influences the heat-shock response and heat-shock protein expression. PMID:15545649
Assessment of electrocardiographic criteria of left atrial enlargement.

PubMed

Batra, Mahesh Kumar; Khan, Atif; Farooq, Fawad; Masood, Tariq; Karim, Musa

2018-05-01

Background Left atrial enlargement is considered to be a robust, strong, and widely acceptable indicator of cardiovascular outcomes. Echocardiography is the gold standard for measurement of left atrial size, but electrocardiography can be simple, cost-effective, and noninvasive in clinical practice. This study was undertaken to assess the diagnostic accuracy of an established electrocardiographic criterion for left atrial enlargement, taking 2-dimensional echocardiography as the gold-standard technique. Methods A cross-sectional study was conducted on 146 consecutively selected patients with the complaints of dyspnea and palpitation and with a murmur detected on clinical examination, from September 10, 2016 to February 10, 2017. Electrocardiography and echocardiography were performed in all patients. Patients with a negative P wave terminal force in lead V 1 > 40 ms·mm on electrocardiography or left atrial dimension > 40 mm on echocardiography were classified as having left atrial enlargement. Sensitivity and specificity were calculated to assess the diagnostic accuracy. Results Taking 2-dimensional echocardiography as the gold-standard technique, electrocardiography correctly diagnosed 68 patients as positive for left atrial enlargement and 12 as negative. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of electrocardiography for left atrial enlargement were 54.4%, 57.1%, 88.3%, 17.4%, and 54.8%, respectively. Conclusion The electrocardiogram appears to be a reasonable indicator of left atrial enlargement. In case of nonavailability of echocardiography, electrocardiography can be used for diagnosis of left atrial enlargement.
The evolution of sexual size dimorphism in the house finch. II. Population divergence in relation to local selection.

PubMed

Badyaev, A V; Hill, G E; Stoehr, A M; Nolan, P M; McGraw, K J

2000-12-01

Recent colonization of ecologically distinct areas in North America by the house finch (Carpodacus mexicanus) was accompanied by strong population divergence in sexual size dimorphism. Here we examined whether this divergence was produced by population differences in local selection pressures acting on each sex. In a long-term study of recently established populations in Alabama, Michigan, and Montana, we examined three selection episodes for each sex: selection for pairing success, overwinter survival, and within-season fecundity. Populations varied in intensity of these selection episodes, the contribution of each episode to the net selection, and in the targets of selection. Direction and intensity of selection strongly differed between sexes, and different selection episodes often favored opposite changes in morphological traits. In each population, current net selection for sexual dimorphism was highly concordant with observed sexual dimorphism--in each population, selection for dimorphism was the strongest on the most dimorphic traits. Strong directional selection on sexually dimorphic traits, and similar intensities of selection in both sexes, suggest that in each of the recently established populations, both males and females are far from their local fitness optimum, and that sexual dimorphism has arisen from adaptive responses in both sexes. Population differences in patterns of selection on dimorphism, combined with both low levels of ontogenetic integration in heritable sexually dimorphic traits and sexual dimorphism in growth patterns, may account for the close correspondence between dimorphism in selection and observed dimorphism in morphology across house finch populations.
Confirmatory Factor Analysis and Differential Relationships of the Two Subdomains of Negative Symptoms in Chronically Ill Psychotic Patients

PubMed Central

Stiekema, Annemarie P. M.; Liemburg, Edith J.; van der Meer, Lisette; Castelein, Stynke; Stewart, Roy; van Weeghel, Jaap; Aleman, André; Bruggeman, Richard

2016-01-01

Research suggests a two factor structure for negative symptoms in patients with psychotic disorders: social amotivation (SA) and expressive deficits (ED). Applying this two-factor structure in clinical settings may provide valuable information with regard to outcomes and to target treatments. We aimed to investigate 1) whether the factor structure is also supported in chronically ill patients with a psychotic disorder and 2) what the relationship is between these factors and functioning (overall functioning and living situation), depressive symptoms and quality of life. 1157 Patients with a psychotic disorder and a duration of illness of 5 years or more were included in the analysis (data selected from the Pharmacotherapy Monitoring Outcome Survey; PHAMOUS). A confirmatory factor analysis was performed using items of the Positive and Negative Syndrome Scale that were previously identified to reflect negative symptoms (N1-4, N6, G5, G7, G13, G16). Subsequently, regression analysis was performed on outcomes. The results confirmed the distinction between SA (N2, N4, G16) and ED (N1, N3, N6, G5, G7, G13) in chronically ill patients. Both factors were related to worse overall functioning as measured with the Health of the Nation Outcome Scales, ED was uniquely associated with residential living status. Higher scores for SA were associated with more depressive symptoms and worse quality of life. Thus, SA is most strongly related to level of social-emotional functioning, while ED are more related to living situation and thereby are indicative of level of everyday functioning. This subdivision may be useful for research purposes and be a valuable additional tool in clinical practice and treatment development. PMID:26895203
Enzymatic polymerization of natural anacardic acid and antibiofouling effects of polyanacardic acid coatings.

PubMed

Chelikani, Rahul; Kim, Yong Hwan; Yoon, Do-Young; Kim, Dong-Shik

2009-05-01

Anacardic acid, separated from cashew nut shell liquid, is well known for its strong antibiotic and antioxidant activities. Recent findings indicate that phenolic compounds from plant sources have an effect on Gram-negative bacteria biofilm formation. In this work, a polyphenolic coating was prepared from anacardic acid using enzymatic synthesis and tested for its effects on biofilm formation of both Gram-negative and Gram-positive bacteria. Natural anacardic acid was enzymatically polymerized using soybean peroxidase. Hydrogen peroxide and phenothiazine-10-propionic acid were used as an oxidizing agent and redox mediator, respectively. Nuclear magnetic resonance and Fourier transform infrared (FTIR) analyses showed the formation of oxyphenylene and phenylene units through the phenol rings. No linkage through the alkyl chain was observed, which proved a high chemo-selectivity of the enzyme. Aqueous solvents turned out to play an important role in the polymer production yield and molecular weight. With 2-propanol, the highest production yield (61%) of polymer (molecular weight = 3,900) was observed, and with methanol, higher-molecular-weight polymers (5,000) were produced with lower production yields (43%). The resulting polyanacardic acid was cross-linked on a solid surface to form a permanent natural polymer coating. The FTIR analysis indicates that the cross-linking between the polymers took place through the unsaturated alkyl side chains. The polyanacardic acid coating was then tested for its antibiofouling effect against Gram-negative and Gram-positive bacteria and compared with the antibiofouling effects of polycardanol coatings reported in the literature. The polyanacardic acid coating showed more reduction in biofilm formation on its surface than polycardanol coatings in the case of Gram-positive bacteria, while in the case of Gram-negative bacteria, it showed a similar reduction in biofilm formation as polycardanol.
Pharmacists levels of emotionality and career success correlates: an exploratory study.

PubMed

Lonie, John M; Marzella, Nino; Perry, Richard; Shah, Bupendra; Jariwala, Jesal

2015-06-01

The objectives of this study were to (1) examine the relationships between Emotional Thinking Scale (ETS) scores and demographic variables such as income, years worked as a pharmacist, and hours worked per week and (2) determine the distribution of ETS scores among this sample of pharmacists. These objectives are significant to explore because they may provide important data regarding effective and ineffective pharmacist work-related behaviors that affect career and life success. A convenience sample of practicing pharmacists was selected. Participants completed the 8-item ETS and a demographic survey. The ETS predicts how an individual's thoughts might influence his or her emotions and behaviors. Researchers analyzed participant's ETS scores with his or her demographic responses. Data were analyzed using SPSS statistical software. One hundred twenty-five pharmacists completed the survey. Twenty-one percent of the sample scored between slightly high and very extremely high on the ETS. "often being incapacitated by strong feelings" correlated negatively with annual income r = -.309 (P = .008); "relying on feelings to deal with complex situations" correlated negatively with annual income r = -.253 (P = .026), with the "number of years practicing pharmacy" r = -.317 (P = .007), and "number of hours worked each week" r = -.317 (P = .007); and "focusing on details thus losing the big picture" was correlated negatively with annual income r = .215 (P = .05). These findings are consistent with the previous ETS research. The variables of interest in this study were negatively but significantly related. Emotional thinking scores decreased with pharmacy practice experience and may be counterproductive for career goals. Entry-level pharmacy education and continuing education programs may help develop self-awareness to this issue. © The Author(s) 2014.
Stress and physiological, behavioral and performance patterns of children under varied air ion levels

NASA Astrophysics Data System (ADS)

Fornof, K. T.; Gilbert, G. O.

1988-12-01

The possibility that individual differences in reactivity to stressors are a major factor underlying discordant results reported for air ion studies prompted an investigation of response patterns in school children under both normal indoor air ion levels and moderately increased negative air ion levels (4000±500/cm3). It was hypothesized that the impact of stressors is reduced with high negative air ionization, and that resultant changes in stress effects would be differentially exhibited according to the children's normal degree of stimulus reactivity. A counter-balanced, replicative, withinssubject design was selected, and the subjects were 12 environmentally sensitive, 1st 4th grade school children. In addition to monitoring stress effects on activity level, attention span, concentration to task and conceptual performance, measures were also made of urinary 5-hydroxyindole acetic acid levels and skin resistance response (SRR) to determine if changes extended to the physiological state. The cold water test was used to add physical stress and enable calculations of Lacey's autonomic lability scores (ALS) as indicators of individual reactivity. The results show main effects for air ions on both physiological parameters, with 48% less change in %SRR ( P<0.01) and 46% less change in urinary 5-HIAA levels ( P<0.055) during negative air ions, indicating increased stress tolerance. Strong interactive effects for ALS x air ion condition appeared, with high and low ALS children reacting oppositely to negative air ions in measures of skin resistance level ( P<0.01), wrist activity ( P<0.01) and digit span backwards ( P<0.004). Thus individual differences in autonomic reactivity and the presence or absence of stressors appear as critical elements for internal validity, and in preventing consequent skewed results from obscuring progress in air ion research.
Development and psychometric evaluation of a clinical global impression for schizoaffective disorder scale.

PubMed

Allen, Michael H; Daniel, David G; Revicki, Dennis A; Canuso, Carla M; Turkoz, Ibrahim; Fu, Dong-Jing; Alphs, Larry; Ishak, K Jack; Bartko, John J; Lindenmayer, Jean-Pierre

2012-01-01

The Clinical Global Impression for Schizoaffective Disorder scale is a new rating scale adapted from the Clinical Global Impression scale for use in patients with schizoaffective disorder. The psychometric characteristics of the Clinical Global Impression for Schizoaffective Disorder are described. Content validity was assessed using an investigator questionnaire. Inter-rater reliability was determined with 12 sets of videotaped interviews rated independently by two trained individuals. Test-retest reliability was assessed using 30 randomly selected raters from clinical trials who evaluated the same videos on separate occasions two weeks apart. Convergent and divergent validity and effect size were evaluated by comparing scores between the Clinical Global Impression for Schizoaffective Disorder and the Positive and Negative Syndrome Scale, 21-item Hamilton Rating Scale for Depression, and Young Mania Rating Scale scales using pooled patient data from two clinical trials. Clinical Global Impression for Schizoaffective Disorder scores were then linked to corresponding Positive and Negative Syndrome Scale scores. Content validity was strong. Inter-rater agreement was good to excellent for most scales and subscales (intra-class correlation coefficient ≥ 0.50). Test-retest showed good reproducibility, with intraclass correlation coefficients ranging from 0.444 to 0.898. Spearman correlations between Clinical Global Impression for Schizoaffective Disorder domains and corresponding symptom scales were 0.60 or greater, and effect sizes for Clinical Global Impression for Schizoaffective Disorder overall and domain scores were similar to Positive and Negative Syndrome Scale Young Mania Rating Scale, and 21-item Hamilton Rating Scale for Depression scores. Raters anticipated that the scale might be less effective in distinguishing negative from depressive symptoms, and, in fact, the results here may reflect that clinical reality. Multiple lines of evidence support the reliability and validity of the Clinical Global Impression for Schizoaffective Disorder for studies in schizoaffective disorder.
The role of negative affect and message credibility in perceived effectiveness of smokeless tobacco health warning labels in Navi Mumbai, India and Dhaka, Bangladesh: A moderated-mediation analysis.

PubMed

Mutti-Packer, Seema; Reid, Jessica L; Thrasher, James F; Romer, Daniel; Fong, Geoffrey T; Gupta, Prakash C; Pednekar, Mangesh S; Nargis, Nigar; Hammond, David

2017-10-01

There is strong evidence showing that pictorial health warnings are more effective than text-only warnings. However, much of this evidence comes from high-income countries and is limited to cigarette packaging. Moreover, few studies have identified mechanisms that might explain the impact of warnings. The current study examined the potential mediating role of negative affect and the moderating influence of message credibility in perceived effectiveness of smokeless tobacco warnings in two low- and middle-income countries (LMICs). Field interviews were conducted in India and Bangladesh, with adult (19+ years) smokeless tobacco users (n=1053), and youth (16-18years) users (n=304) and non-users (n=687). Respondents were randomly assigned to view warnings in one of four conditions: (1) Text-only, (2) pictorial with symbolic imagery, (3) pictorial with graphic images of health effects, or (4) pictorial with personalized graphic images plus a personal testimonial. The findings provide support for the mediating influence of negative affect in perceived effectiveness, for adult and youth smokeless tobacco users who viewed pictorial warnings (vs. text-only), and graphic health warnings (vs. personal testimonials). Among adults, message credibility moderated the indirect effect; the association was stronger when credibility was high and weaker when it was low. Among youth users and non-users, message credibility did not moderate the indirect effect. Consistent with research from high-income countries, these findings highlight the importance of selecting imagery that will elicit negative emotional reactions and be perceived as credible. Differential effects among adults and youth highlight the importance of pre-testing images. Copyright © 2017 Elsevier Ltd. All rights reserved.
IQ and Fertility: A Cross-National Study

ERIC Educational Resources Information Center

Shatz, Steven M.

2008-01-01

Many studies have found a small to moderate negative correlation between IQ and fertility rates. However, these studies have been limited to the United States and some European countries. The present study was a between-nation study using national IQ scores and national fertility rates. There were strong negative correlations found between…
Insight into structural requirements for selective and/or dual CXCR3 and CXCR4 allosteric modulators.

PubMed

Kolarič, Anja; Švajger, Urban; Tomašič, Tihomir; Brox, Regine; Frank, Theresa; Minovski, Nikola; Tschammer, Nuska; Anderluh, Marko

2018-05-11

Based on the previously published pyrazolopyridine-based hit compound for which negative allosteric modulation of both CXCR3 and CXCR4 receptors was disclosed, we designed, synthesized and biologically evaluated a set of novel, not only negative, but also positive allosteric modulators with preserved pyrazolopyridine core. Compound 9e is a dual negative modulator, inhibiting G protein activity of both receptors. For CXCR4 receptor para-substituted aromatic group of compounds distinguishes between negative and positive modulation. Para-methoxy substitution leads to functional antagonism, while para-chloro triggers agonism. Additionally, we discovered that chemotaxis is not completely correlated with G protein pathways. This is the first work in which we have on a series of compounds successfully demonstrated that it is possible to produce selective as well as dual-acting modulators of chemokine receptors, which is very promising for future research in the field of discovery of selective or dual modulators of chemokine receptors. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Impulsivity and Alcohol-Related Risk among College Students: Examining Urgency, Sensation Seeking and the Moderating Influence of Beliefs about Alcohol's Role in the College Experience

PubMed Central

LaBrie, Joseph W.; Kenney, Shannon R.; Napper, Lucy E.; Miller, Kevin

2013-01-01

The personality trait of impulsivity is predictive of heavy drinking and consequences among college students. The current study examined how impulsivity—measured via positive urgency, negative urgency, and sensation seeking—and a person's beliefs about the role alcohol plays in the college experience relate to drinking and consequences in a sample of 470 college students (mean age = 19 years, 61.3% female, 59.8% white). In support of hypotheses, sensation seeking independently predicted greater drinking, and both positive and negative urgency predicted greater experience of alcohol-related negative consequences after controlling for consumption level. Moreover, alcohol beliefs moderated the relationship between impulsivity types and alcohol outcomes. Among students high (versus low) in sensation seeking, strong beliefs about alcohol's role in college life were related to significantly greater drinking, and among students high (versus low) in negative urgency, endorsing strong beliefs about alcohol's role in college life were related to greater levels of alcohol-related negative consequences. Overall, findings inform college prevention efforts by highlighting the need to distinguish unique facets of impulsivity and examine how they intersect with students’ beliefs about alcohol in college. PMID:24120644
Impulsivity and alcohol-related risk among college students: examining urgency, sensation seeking and the moderating influence of beliefs about alcohol's role in the college experience.

PubMed

LaBrie, Joseph W; Kenney, Shannon R; Napper, Lucy E; Miller, Kevin

2014-01-01

The personality trait of impulsivity is predictive of heavy drinking and consequences among college students. The current study examined how impulsivity-measured via positive urgency, negative urgency, and sensation seeking-and a person's beliefs about the role alcohol plays in the college experience relate to drinking and consequences in a sample of 470 college students (mean age=19 years, 61.3% female, 59.8% White). In support of the hypotheses, sensation seeking independently predicted greater drinking, and both positive urgency and negative urgency predicted greater experience of alcohol-related negative consequences after controlling for consumption level. Moreover, alcohol beliefs moderated the relationship between impulsivity types and alcohol outcomes. Among students high (versus low) in sensation seeking, strong beliefs about alcohol's role in college life were related to significantly greater drinking, and among students high (versus low) in negative urgency, endorsing strong beliefs about alcohol's role in college life were related to greater levels of alcohol-related negative consequences. Overall, findings inform college prevention efforts by highlighting the need to distinguish unique facets of impulsivity and examine how they intersect with students' beliefs about alcohol in college. © 2013.
Context-specific control and the Stroop negative priming effect.

PubMed

Milliken, Bruce; Thomson, David R; Bleile, Karmen; MacLellan, Ellen; Giammarco, Maria

2012-01-01

The present study highlights the utility of context-specific learning for different probe types in accounting for the commonly observed dependence of negative priming on probe selection. Using a Stroop priming procedure, Experiments 1a and 1b offered a demonstration that Stroop priming effects can differ qualitatively for selection and no-selection probes when probe selection is manipulated between subjects, but not when it is manipulated randomly from trial to trial within subject (see also Moore, 1994). In Experiments 2 and 3, selection and no-selection probes served as two contexts that varied randomly from trial to trial, but for which proportion repeated was manipulated separately. A context-specific proportion repeated effect was observed in Experiment 2, characterized by modest quantitative shifts in the repetition effects as a function of the context-specific proportion repeated manipulation. However, with a longer intertrial interval in Experiment 3, a context-specific proportion repeated manipulation that focused on the no-selection probes changed the repetition effect qualitatively, from negative priming when the proportion repeated was .25 to positive priming when the proportion repeated was .75. The results are discussed with reference to the role of rapid, context-specific learning processes in the integration of prior experiences with current perception and action.
Pollen-specific, but not sperm-specific, genes show stronger purifying selection and higher rates of positive selection than sporophytic genes in Capsella grandiflora.

PubMed

Arunkumar, Ramesh; Josephs, Emily B; Williamson, Robert J; Wright, Stephen I

2013-11-01

Selection on the gametophyte can be a major force shaping plant genomes as 7-11% of genes are expressed only in that phase and 60% of genes are expressed in both the gametophytic and sporophytic phases. The efficacy of selection on gametophytic tissues is likely to be influenced by sexual selection acting on male and female functions of hermaphroditic plants. Moreover, the haploid nature of the gametophytic phase allows selection to be efficient in removing recessive deleterious mutations and fixing recessive beneficial mutations. To assess the importance of gametophytic selection, we compared the strength of purifying selection and extent of positive selection on gametophyte- and sporophyte-specific genes in the highly outcrossing plant Capsella grandiflora. We found that pollen-exclusive genes had a larger fraction of sites under strong purifying selection, a greater proportion of adaptive substitutions, and faster protein evolution compared with seedling-exclusive genes. In contrast, sperm cell-exclusive genes had a smaller fraction of sites under strong purifying selection, a lower proportion of adaptive substitutions, and slower protein evolution compared with seedling-exclusive genes. Observations of strong selection acting on pollen-expressed genes are likely explained by sexual selection resulting from pollen competition aided by the haploid nature of that tissue. The relaxation of selection in sperm might be due to the reduced influence of intrasexual competition, but reduced gene expression may also be playing an important role.
Detecting negative selection on recurrent mutations using gene genealogy

PubMed Central

2013-01-01

Background Whether or not a mutant allele in a population is under selection is an important issue in population genetics, and various neutrality tests have been invented so far to detect selection. However, detection of negative selection has been notoriously difficult, partly because negatively selected alleles are usually rare in the population and have little impact on either population dynamics or the shape of the gene genealogy. Recently, through studies of genetic disorders and genome-wide analyses, many structural variations were shown to occur recurrently in the population. Such “recurrent mutations” might be revealed as deleterious by exploiting the signal of negative selection in the gene genealogy enhanced by their recurrence. Results Motivated by the above idea, we devised two new test statistics. One is the total number of mutants at a recurrently mutating locus among sampled sequences, which is tested conditionally on the number of forward mutations mapped on the sequence genealogy. The other is the size of the most common class of identical-by-descent mutants in the sample, again tested conditionally on the number of forward mutations mapped on the sequence genealogy. To examine the performance of these two tests, we simulated recurrently mutated loci each flanked by sites with neutral single nucleotide polymorphisms (SNPs), with no recombination. Using neutral recurrent mutations as null models, we attempted to detect deleterious recurrent mutations. Our analyses demonstrated high powers of our new tests under constant population size, as well as their moderate power to detect selection in expanding populations. We also devised a new maximum parsimony algorithm that, given the states of the sampled sequences at a recurrently mutating locus and an incompletely resolved genealogy, enumerates mutation histories with a minimum number of mutations while partially resolving genealogical relationships when necessary. Conclusions With their considerably high powers to detect negative selection, our new neutrality tests may open new venues for dealing with the population genetics of recurrent mutations as well as help identifying some types of genetic disorders that may have escaped identification by currently existing methods. PMID:23651527
Time trends, environmental factors and genetic basis of semen traits collected in Holstein bulls under commercial conditions.

PubMed

Karoui, Sofiene; Díaz, Clara; Serrano, Magdalena; Cue, Roger; Celorrio, Idoia; Carabaño, María J

2011-03-01

The fact that results of artificial insemination (AI) are declining in highly selected dairy cattle populations has added a renewed interest to the evaluation of male fertility. Data from 42,348 ejaculates collected from 1990 to 2007 on 502 Holstein bulls were analysed in a Bayesian framework to provide estimates of the evolution of semen traits routinely collected in AI centres throughout the last decades of intense selection for production traits and estimate genetic parameters. The traits under consideration were volume (VOL), concentration (CONC), number of spermatozoa per ejaculate (NESPZ), mass motility score (MM), individual motility (IM), and post-thawing motility (PTM). The environmental factors studied were year-season and week of collection, which account for changes in environmental and technical conditions along time, age at collection, ejaculate order, time from previous collection (TPC) and time between collection and freezing (TCF) (only for PTM). Bull's inbreeding coefficient (Fi), bull's permanent environmental and additive genetic effects were also considered. The use of reduced models was evaluated using the Bayes factor. For all the systematic effects tested, strong or very strong evidence in favour of including the effect in the model was obtained, except for Fi for motility traits and TCF for PTM. No systematic time trends for environment or bull effects were observed, except for PTM, which showed an increasing environmental trend, associated with improvements in freezing-thawing protocols. Heritability estimates were moderate (0.16-0.22), except for IM, which presented a low value (0.07). Genetic correlations among motilities and between motilities and CONC were large and positive [0.38-0.87], VOL showed a negative correlation with CONC (-0.13) but with ample HPD 95%. The magnitude of heritabilities would allow an efficient selection if required and grants the use of these traits as indicators of the sperm viability component of bulls breeding soundness. Copyright © 2011 Elsevier B.V. All rights reserved.
Electron-Phonon and Electron-Electron Interactions in Individual Suspended Carbon Nanotubes

NASA Astrophysics Data System (ADS)

Cronin, Stephen

2010-03-01

The fabrication of pristine, nearly defect-free, suspended carbon nanotubes (CNTs) enables the observation of several phenomena not seen before in carbon nanotubes, including breakdown of the Born-Oppenheimer approximation^1, mode selective electron-phonon coupling^2, and a Mott insulator transition^3. Raman spectroscopy of these nanotubes under applied gate and bias potentials reveals exceptionally strong electron-phonon coupling, arising from Kohn anomalies, which result in mode selective electron-phonon coupling, negative differential conductance (NDC), and non-equilibrium phonon populations^2,4. Due to the extremely long electron lifetimes, we observe a breakdown of the Born-Oppenheimer approximation, as deduced from the gate voltage-induced changes in the vibrational energies of suspended carbon nanotubes^1. We also report strikingly large variations in the Raman intensity of pristine metallic CNTs in response to gate voltages, which are attributed to a Mott insulating state of the strongly correlated electrons^3. As will be shown, preparing clean, defect-free devices is an essential prerequisite for studying the rich low-dimensional physics of CNTs. (1.) Bushmaker, A.W., Deshpande, V.V., Hsieh, S., Bockrath, M.W., and Cronin, S.B., ``Direct Observation of Born-Oppenheimer Approximation Breakdown in Carbon Nanotubes.'' Nano Letters, 9, 607 (2009). (2.) Bushmaker, A.W., Deshpande, V.V., Bockrath, M.W., and Cronin, S.B., ``Direct Observation of Mode Selective Electron-Phonon Coupling in Suspended Carbon Nanotubes.'' Nano Letters, 7, 3618 (2007) (3.) Bushmaker, A.W., Deshpande, V.V., Hsieh, S., Bockrath, M.W., and Cronin, S.B., ``Large Modulations in the Intensity of Raman-Scattered Light from Pristine Carbon Nanotubes.'' Physical Review Letters, 103, 067401 (2009). (4.) Bushmaker, A.W., Deshpande, V.V., Hsieh, S., Bockrath, M.W., and Cronin, S.B., ``Gate Voltage Controlled Non-Equilibrium and Non-Ohmic Behavior in Suspended Carbon Nanotubes.'' Nano Letters, 9, 2862 (2009)
An investigation of the effect of body dissatisfaction on selective attention toward negative shape and weight-related information.

PubMed

Smith, Evelyn; Rieger, Elizabeth

2010-05-01

The aim of the present study was to investigate the effect of inducing body dissatisfaction on selective attention toward negative shape and weight-related information. A total of 54 female undergraduate university students were randomly allocated to one of three induction conditions: body dissatisfaction, negative mood, and neutral. Subsequently, participants' attentional bias toward negative shape/weight words was measured using a dot probe task. Contrary to the hypotheses, participants in the body dissatisfaction condition did not demonstrate an increase in attention toward negative shape/weight words compared with the negative mood and neutral conditions. Indeed, it was the negative mood induction that resulted in significantly increased attention toward negative shape/weight words relative to the body dissatisfaction condition. The finding that the negative mood (rather than the body dissatisfaction) induction triggered an attentional bias toward shape- and weight-related information is discussed in terms of the anxiety literature given the nature of the mood induction utilized. This finding might help to account for the high comorbidity between eating disorders and anxiety disorders and suggests the possible relevance of attentional training interventions designed for anxiety disorders in the treatment of eating disorders. 2009 by Wiley Periodicals, Inc.
Praziquantel decreases fecundity in Schistosoma mansoni adult worms that survive treatment: evidence from a laboratory life-history trade-offs selection study.

PubMed

Lamberton, Poppy H L; Faust, Christina L; Webster, Joanne P

2017-06-16

Mass drug administration of praziquantel is the World Health Organization's endorsed control strategy for schistosomiasis. A decade of annual treatments across sub-Saharan Africa has resulted in significant reductions of infection prevalence and intensity levels, although 'hotspots' remain. Repeated drug treatments place strong selective pressures on parasites, which may affect life-history traits that impact transmission dynamics. Understanding drug treatment responses and the evolution of such traits can help inform on how to minimise the risk of drug resistance developing, maximise sustainable control programme success, and improve diagnostic protocols. We performed a four-generation Schistosoma mansoni praziquantel selection experiment in mice and snails. We used three S. mansoni lines: a praziquantel-resistant isolate (R), a praziquantel-susceptible isolate (S), and a co-infected line (RS), under three treatment regimens: untreated, 25 mg/kg praziquantel, or 50 mg/kg praziquantel. Life-history traits, including parasite adult-worm establishment, survival, reproduction (fecundity), and associated morbidity, were recorded in mice across all four generations. Predictor variables were tested in a series of generalized linear mixed effects models to determine which factors had a significant influence on parasite life-history traits in definitive hosts under different selection regimes. Praziquantel pressure significantly reduced adult-worm burdens across all generations and isolates, including within R-lines. However, previous drug treatment resulted in an increase in adult-worm establishment with increasing generation from P1 to F3. The highest worm numbers were in the co-infected RS line. Praziquantel treatment decreased adult-worm burden, but had a larger negative impact on the mean daily number of miracidia, a proxy for fecundity, across all three parasite isolates. Our predicted cost of resistance was not supported by the traits we measured within the murine host. We did not find evidence for negative adult worm density-dependent effects on fecundity. In contrast, of the adult worms that survived treatment, even low doses of praziquantel significantly reduced adult-worm fecundity. Such reductions in worm fecundity post treatment suggest that egg - based measures of drug efficacy, such as Kato-Katz, may overestimate the short-term effect of praziquantel on adult - worm burdens. These findings have important implications for S. mansoni transmission control, diagnostic protocols, and the potential for undetected selection toward drug resistance.
Depression, Craving, and Substance Use Following a Randomized Trial of Mindfulness-Based Relapse Prevention

ERIC Educational Resources Information Center

Witkiewitz, Katie; Bowen, Sarah

2010-01-01

Objective: A strong relation between negative affect and craving has been demonstrated in laboratory and clinical studies, with depressive symptomatology showing particularly strong links to craving and substance abuse relapse. Mindfulness-based relapse prevention (MBRP), shown to be efficacious for reduction of substance use, uses…
Drug Use and Attitudes Toward Social and Legal Aspects of Marijuana in a Large Metropolitan University

ERIC Educational Resources Information Center

Martino, Edward R.; Truss, Carroll V.

1973-01-01

Attitude toward marijuana shifted from strongly negative to strongly positive as frequency of marijuana use increased. With frequency of use controlled, attitude toward marijuana was even more favorable when other drugs had been tried, and also among students who were religiously inactive. (Author)
Profilometry and subsurface imaging in point of care diagnosis in ocular disease and lymphedema after breast cancer treatment

NASA Astrophysics Data System (ADS)

Sayegh, Samir I.; Taghian, Alphonse

2013-03-01

Breast cancer-related lymphedema (BCRL) can be irreversible with profound negative impact on patients' quality of life. Programs that provide screening and active surveillance for BCRL are essential to determine whether early detection and intervention influences the course of lymphedema development. Established methods of quantitatively assessing lymphedema at early stages include "volume" methods such as perometry and bioimpedance spectroscopy. Here we demonstrate 1) Use of topographical techniques analogous to those used in corneal topography 2) Development of point-of-care lymphedema detection and characterization based on off-the-shelf hardward 3) The role of subsurface imaging 4) Multimodal diagnostics and integration yielding higher sensitivity/ specificity.
Bacteriological aspects of selective decontamination of the digestive tract as a method of infection prevention in granulocytopenic patients.

PubMed Central

de Vries-Hospers, H G; Sleijfer, D T; Mulder, N H; van der Waaij, D; Neiweg, H O; van Saene, H K

1981-01-01

We describe the bacteriological results of a controlled clinical trial of selective decontamination of the digestive tract as a method of infection prevention in granulocytopenic patients. Selective elimination of Enterobacteriaceae and Pseudomonadaceae species was accomplished by the oral administration of nalidixic acid, co-trimoxazole, or polymyxin. Yeasts were eliminated selectively by amphotericin B or nystatin treatment. The drugs used in this study were chosen because of their capacities to selectively eliminate gram-negative rods and yeast without affecting the anaerobic part of the gut flora which is responsible for colonization resistance. Compared with the control group, the selectively decontaminated patients had significantly fewer (P less than 0.0005) gram-negative rods or yeasts or both in their throat swab cultures and in their feces. This reduction may explain the clinical effectiveness of selective decontamination. PMID:7027923
An analysis on the fate of a selection of blood products derived from cytomegalovirus-seronegative donors at three tertiary referral hospitals in Australia.

PubMed

Hirani, Rena; Tohidi-Esfahani, Ibrahim; Mondy, Phillip; Irving, David O

2018-03-01

Supply of cytomegalovirus (CMV)-seronegative blood products in Australia is an ongoing challenge. Requests for CMV-negative products are increasing with prediction that the demand will exceed supply by 2019. Clinical information evaluating how these products are being utilized by health providers within Australia is limited. This study aimed to identify indications for use of CMV-negative blood products and gather data to support possible practice change. All CMV-negative products issued to three tertiary Australian hospitals from May 1, 2016, to May 31, 2016, were identified (n = 1219). This equated to 1044 red blood cell units and 175 platelet units. Data were collected on the fate of each unit. Information collected included the indication and urgency of transfusion, reason for discard, product age, and recipient CMV immunoglobulin G status. Of the units issued during the audit period, 32 (2.6%) were discarded by the hospitals. Transfusion data were collected on 411 units. Of these, 136 (33.1%) were transfused to CMV-positive recipients, in most cases for hematology indications, and 67 units (16.3%) were transfused to CMV-negative requiring recipients. A total of 144 (35%) CMV-negative units were selected based on their irradiation status. Other reasons for the selection of CMV-negative units included product close to expiry (n = 134, 32.6%) or specific patient phenotype requirements (n = 31, 7.5%). In this study, the majority of CMV-negative blood products were not used for CMV-negative requiring recipients. Alterations to inventory management would be advantageous to ensure continued supply for CMV-negative requiring recipients. © 2017 AABB.
Framing effects: the influence of handedness and access to right hemisphere processing.

PubMed

Stein, Jeannette M

2012-01-01

Changing how information is framed, such that the same critical information is cast in a positive or negative light, has a powerful impact on judgements and decision making. Research indicates that the influence of frames may be driven by participants' initial affective response and that the right hemisphere is sensitive to the emotional connotation of stimuli. While previous research tested the effects of hemispheric differences on framing effects by inducing asymmetrical activation, the current study explored how stable brain differences may account for differences in susceptibility to framing effects. Because mixed degree of handedness is associated with increased access to right hemisphere processes, mixed-handed participants were expected to be more susceptible to the effects of framing than strong-handed participants. Participants responded to the Asian disease problem and completed as assessment of handedness. Although mixed- and strong-handed participants were affected differently, the results were not consistent with the hypothesis. Mixed-handed participants conformed to risky choice framing effects when options were framed negatively and showed no effect of the positive frame. Strong-handed participants conformed to positively framed options and showed no effect of the negative frame. Possible explanations are discussed.
Sentiment Diffusion of Public Opinions about Hot Events: Based on Complex Network

PubMed Central

Hao, Xiaoqing; An, Haizhong; Zhang, Lijia; Li, Huajiao; Wei, Guannan

2015-01-01

To study the sentiment diffusion of online public opinions about hot events, we collected people’s posts through web data mining techniques. We calculated the sentiment value of each post based on a sentiment dictionary. Next, we divided those posts into five different orientations of sentiments: strongly positive (P), weakly positive (p), neutral (o), weakly negative (n), and strongly negative (N). These sentiments are combined into modes through coarse graining. We constructed sentiment mode complex network of online public opinions (SMCOP) with modes as nodes and the conversion relation in chronological order between different types of modes as edges. We calculated the strength, k-plex clique, clustering coefficient and betweenness centrality of the SMCOP. The results show that the strength distribution obeys power law. Most posts’ sentiments are weakly positive and neutral, whereas few are strongly negative. There are weakly positive subgroups and neutral subgroups with ppppp and ooooo as the core mode, respectively. Few modes have larger betweenness centrality values and most modes convert to each other with these higher betweenness centrality modes as mediums. Therefore, the relevant person or institutes can take measures to lead people’s sentiments regarding online hot events according to the sentiment diffusion mechanism. PMID:26462230
Distribution of the Crustal Magnetic Field in Sichuan-Yunnan Region, Southwest China

PubMed Central

Bai, Chunhua; Kang, Guofa; Gao, Guoming

2014-01-01

Based on the new and higher degree geomagnetic model NGDC-720-V3, we have investigated the spatial distribution, the altitude decay characteristics of the crustal magnetic anomaly, the contributions from different wavelength bands to the anomaly, and the relationship among the anomaly, the geological structure, and the geophysical field in Sichuan-Yunnan region of China. It is noted that the most outstanding feature in this area is the strong positive magnetic anomaly in Sichuan Basin, a geologically stable block. Contrasting with this feature, a strong negative anomaly can be seen nearby in Longmen Mountain block, an active block. This contradiction implies a possible relationship between the magnetic field and the geological activity. Completely different feature in magnetic field distribution is seen in the central Yunnan block, another active region, where positive and negative anomalies distribute alternatively, showing a complex magnetic anomaly map. Some fault belts, such as the Longmen Mountain fault, Lijiang-Xiaojinhe fault, and the Red River fault, are the transitional zones of strong and weak or negative and positive anomalies. The corresponding relationship between the magnetic anomaly and the geophysical fields was confirmed. PMID:25243232
Using Negative Reinforcement to Increase Self-Feeding in a Child with Food Selectivity

ERIC Educational Resources Information Center

Vaz, Petula C. M.; Volkert, Valerie M.; Piazza, Cathleen C.

2011-01-01

We examined the effects of a negative reinforcement-based treatment on the self-feeding of 1 child with food selectivity by type and texture. Self-feeding increased when the child could choose to either self-feed 1 bite of a target food or be fed 1 bite of the target food and 5 bites of another food. Possible mechanisms that underlie the…
Kernel Extended Real-Valued Negative Selection Algorithm (KERNSA)

DTIC Science & Technology

2013-06-01

are discarded, which is similar to how T-cells function in the BIS. An unlabeled, future sample is considered non -self if any detectors match it. This...Affinity Performs Best With Each type of Dataset 65 5.1.4 More Kernel Functions . . . . . . . . . . . . . . . . . . . . . . . . 65 5.1.5 Automate the...13 2.5 The Negative Selection Algorithm (NSA). . . . . . . . . . . . . . . . . . . . . 16 2.6 Illustration of self and non -self
Models of microbiome evolution incorporating host and microbial selection.

PubMed

Zeng, Qinglong; Wu, Steven; Sukumaran, Jeet; Rodrigo, Allen

2017-09-25

Numerous empirical studies suggest that hosts and microbes exert reciprocal selective effects on their ecological partners. Nonetheless, we still lack an explicit framework to model the dynamics of both hosts and microbes under selection. In a previous study, we developed an agent-based forward-time computational framework to simulate the neutral evolution of host-associated microbial communities in a constant-sized, unstructured population of hosts. These neutral models allowed offspring to sample microbes randomly from parents and/or from the environment. Additionally, the environmental pool of available microbes was constituted by fixed and persistent microbial OTUs and by contributions from host individuals in the preceding generation. In this paper, we extend our neutral models to allow selection to operate on both hosts and microbes. We do this by constructing a phenome for each microbial OTU consisting of a sample of traits that influence host and microbial fitnesses independently. Microbial traits can influence the fitness of hosts ("host selection") and the fitness of microbes ("trait-mediated microbial selection"). Additionally, the fitness effects of traits on microbes can be modified by their hosts ("host-mediated microbial selection"). We simulate the effects of these three types of selection, individually or in combination, on microbiome diversities and the fitnesses of hosts and microbes over several thousand generations of hosts. We show that microbiome diversity is strongly influenced by selection acting on microbes. Selection acting on hosts only influences microbiome diversity when there is near-complete direct or indirect parental contribution to the microbiomes of offspring. Unsurprisingly, microbial fitness increases under microbial selection. Interestingly, when host selection operates, host fitness only increases under two conditions: (1) when there is a strong parental contribution to microbial communities or (2) in the absence of a strong parental contribution, when host-mediated selection acts on microbes concomitantly. We present a computational framework that integrates different selective processes acting on the evolution of microbiomes. Our framework demonstrates that selection acting on microbes can have a strong effect on microbial diversities and fitnesses, whereas selection on hosts can have weaker outcomes.

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