Cotard Syndrome.

PubMed

Dieguez, Sebastian

2018-01-01

Cotard's syndrome is often described as the delusional belief that one is dead or non-existent. However, Jules Cotard's initial description (1880) of the "delusion of negations" was much richer and also involved delusions and claims of immortality and enormity, feelings of damnation, and illusions of bodily dissolution and transformation. Alternatively conceived as an extreme case of depression, hypochondria, or psychosis, the condition is considered rare and remains poorly understood. Cotard himself provided a taxonomy and several explanations for the condition, focusing on its distinction from classical persecutory delusions and suggesting that it could be a kind of reversed grandiosity. He proposed a psychosensory basis in the dissolution of mental imagery, which he then extended to a more general psychomotor impairment of volition. Other early authors highlighted a disorder of the bodily self, and more recent theories postulated an impairment of right hemispheric functions, leading to perceptual and somatosensory feelings of unreality, which coupled with reasoning impairments and an internalized attributional style led in turn to beliefs of non-existence. However, despite its striking presentation and its relevance to our understanding of self-awareness, Cotard's syndrome remains an elusive condition, rarely reported and poorly researched. © 2018 S. Karger AG, Basel.

Differences among Major Taxa in the Extent of Ecological Knowledge across Four Major Ecosystems

PubMed Central

Fisher, Rebecca; Knowlton, Nancy; Brainard, Russell E.; Caley, M. Julian

2011-01-01

Existing knowledge shapes our understanding of ecosystems and is critical for ecosystem-based management of the world's natural resources. Typically this knowledge is biased among taxa, with some taxa far better studied than others, but the extent of this bias is poorly known. In conjunction with the publically available World Registry of Marine Species database (WoRMS) and one of the world's premier electronic scientific literature databases (Web of Science®), a text mining approach is used to examine the distribution of existing ecological knowledge among taxa in coral reef, mangrove, seagrass and kelp bed ecosystems. We found that for each of these ecosystems, most research has been limited to a few groups of organisms. While this bias clearly reflects the perceived importance of some taxa as commercially or ecologically valuable, the relative lack of research of other taxonomic groups highlights the problem that some key taxa and associated ecosystem processes they affect may be poorly understood or completely ignored. The approach outlined here could be applied to any type of ecosystem for analyzing previous research effort and identifying knowledge gaps in order to improve ecosystem-based conservation and management. PMID:22073172

Current applications of nanotechnology in dentistry: a review.

PubMed

Bhavikatti, Shaeesta Khaleelahmed; Bhardwaj, Smiti; Prabhuji, M L V

2014-01-01

With the increasing demand for advances in diagnosis and treatment modalities, nanotechnology is being considered as a groundbreaking and viable research subject. This technology, which deals with matter in nanodimensions, has widened our views of poorly understood health issues and provided novel means of diagnosis and treatment. Researchers in the field of dentistry have explored the potential of nanoparticles in existing therapeutic modalities with moderate success. The key implementations in the field of dentistry include local drug delivery agents, restorative materials, bone graft materials, and implant surface modifications. This review provides detailed insights about current developments in the field of dentistry, and discusses potential future uses of nanotechnology.

The Nature and Origin of Aromatic Organic Matter in the Tagish Lake Meteorite

NASA Technical Reports Server (NTRS)

Clemett, S. J.; Keller, L. P.; Nakamura, K.; McKay, D. S.

2004-01-01

The Tagish Lake meteorite is an unusual carbonaceous chondrite that does not fit well within existing chondrite taxonomy. Bulk analyses suggest approx. 5 wt.% C of which approx. 1 wt.% is in the form of organic matter and the remainder is present as inorganic carbonate. The exact nature and form of this organic component is, as is the case with the other ordinary and carbonaceous chondrites, still poorly understood. Yet its significance has far reaching implications, from contributing to the abiotic evolution of the early Earth and Mars, to providing geothermal constraints in the evolution of the Solar nebula.

Preservation of Fertility Potential for Gender and Sex Diverse Individuals.

PubMed

Johnson, Emilie K; Finlayson, Courtney

2016-01-01

Gender and sex diverse individuals-transgender individuals and those with disorders of sex development (DSD)-both face medical treatments that may impair biological fertility potential. Young DSD patients also often have abnormal gonadal development. Fertility preservation for these populations has historically been poorly understood and rarely addressed. Future fertility should be discussed with gender and sex diverse individuals, particularly given recent advances in fertility preservation technologies and evolving views of fertility potential. Key ethical issues include parental proxy decision-making and uncertainty regarding prepubertal fertility preservation technologies. Many opportunities exist for advancing fertility-related care and research for transgender and DSD patients.

Hydroxycut hepatotoxicity: A case series and review of liver toxicity from herbal weight loss supplements

PubMed Central

Dara, Lily; Hewett, Jennifer; Lim, Joseph Kartaik

2008-01-01

Dietary supplements represent an increasingly common source of drug-induced liver injury. Hydroxycut is a popular weight loss supplement which has previously been linked to hepatotoxicity, although the individual chemical components underlying liver injury remain poorly understood. We report two cases of acute hepatitis in the setting of Hydroxycut exposure and describe possible mechanisms of liver injury. We also comprehensively review and summarize the existing literature on commonly used weight loss supplements, and their individual components which have demonstrated potential for liver toxicity. An increased effort to screen for and educate patients and physicians about supplement-associated hepatotoxicity is warranted. PMID:19058338

Misdiagnosis of attention deficit hyperactivity disorder: ‘Normal behaviour’ and relative maturity

PubMed Central

Ford-Jones, Polly Christine

2015-01-01

Attention deficit hyperactivity disorder (ADHD) is one of the most frequently diagnosed disorders in children, yet it remains poorly understood. Substantial controversy exists regarding correct diagnosis of ADHD, and areas of subjectivity in diagnosis have been identified. Concerns for appropriate diagnosis are critical in terms of children’s educational outcomes, as well as health concerns associated with the use and potential overuse of stimulant medications. There exists a relative-age effect in which children who are relatively younger than their peers and born closest to the school start age cut-off are more frequently diagnosed and treated for ADHD. Additionally, substantial variation exists in ADHD diagnosis between boys and girls, with boys often presenting with more stereotypical symptoms. Both the relative-age effect and variation in sex diagnosis, as well as the challenges of early preschool diagnosis, emphasize the importance of considering relative maturity in ADHD diagnosis of children. Implications and knowledge translation strategies for practitioners, parents and the education system are presented. PMID:26038639

[Stranger isolated minors and the french health care system: qualitative study].

PubMed

Guégan, Marion; Rivollier, Elisabeth

2017-01-01

While waiting for health insurance coverage, unaccompanied foreign minors (UFM) can attend PASS healthcare access clinics in French hospitals. The aim of this study was to identify UFM's representations and perceptions of the French health care system. This qualitative study was based on a series of individual, semi-structured interviews of UFMs attending a PASS clinic. The methodology was approved by the French data protection authority and an ethics committee. A total of 21 UFMs were interviewed. Participants expressed their satisfaction with health care, although the health care system was perceived as a complex system. The prescription is essential, as it enables the patient to obtain medications, the ultimate goal of health care access. Not all participants knew about the existence of national health insurance. They were unable to distinguish between PASS clinics and the hospital in general and the screening role of PASS clinics was often poorly understood. The general practitioner was not always identified and his role was poorly understood. Educators were perceived as playing a decisive role in health care access. Heath is essential for all UFMs. None of them referred to mental health issues. UFMs need better information about the health care system and their rights. The educators' health care support training, their knowledge of the rights of UFMs and the role of healthcare professionals need to be improved. Screening of mental illness needs to be developed.

Resonant activation of population extinctions

NASA Astrophysics Data System (ADS)

Spalding, Christopher; Doering, Charles R.; Flierl, Glenn R.

2017-10-01

Understanding the mechanisms governing population extinctions is of key importance to many problems in ecology and evolution. Stochastic factors are known to play a central role in extinction, but the interactions between a population's demographic stochasticity and environmental noise remain poorly understood. Here we model environmental forcing as a stochastic fluctuation between two states, one with a higher death rate than the other. We find that, in general, there exists a rate of fluctuations that minimizes the mean time to extinction, a phenomenon previously dubbed "resonant activation." We develop a heuristic description of the phenomenon, together with a criterion for the existence of resonant activation. Specifically, the minimum extinction time arises as a result of the system approaching a scenario wherein the severity of rare events is balanced by the time interval between them. We discuss our findings within the context of more general forms of environmental noise and suggest potential applications to evolutionary models.

Enhanced heterogeneous ice nucleation by special surface geometry

PubMed Central

Bi, Yuanfei; Cao, Boxiao; Li, Tianshu

2017-01-01

The freezing of water typically proceeds through impurity-mediated heterogeneous nucleation. Although non-planar geometry generically exists on the surfaces of ice nucleation centres, its role in nucleation remains poorly understood. Here we show that an atomically sharp, concave wedge can further promote ice nucleation with special wedge geometries. Our molecular analysis shows that significant enhancements of ice nucleation can emerge both when the geometry of a wedge matches the ice lattice and when such lattice match does not exist. In particular, a 45° wedge is found to greatly enhance ice nucleation by facilitating the formation of special topological defects that consequently catalyse the growth of regular ice. Our study not only highlights the active role of defects in nucleation but also suggests that the traditional concept of lattice match between a nucleation centre and crystalline lattice should be extended to include a broader match with metastable, non-crystalline structural motifs. PMID:28513603

Enhanced heterogeneous ice nucleation by special surface geometry.

PubMed

Bi, Yuanfei; Cao, Boxiao; Li, Tianshu

2017-05-17

The freezing of water typically proceeds through impurity-mediated heterogeneous nucleation. Although non-planar geometry generically exists on the surfaces of ice nucleation centres, its role in nucleation remains poorly understood. Here we show that an atomically sharp, concave wedge can further promote ice nucleation with special wedge geometries. Our molecular analysis shows that significant enhancements of ice nucleation can emerge both when the geometry of a wedge matches the ice lattice and when such lattice match does not exist. In particular, a 45° wedge is found to greatly enhance ice nucleation by facilitating the formation of special topological defects that consequently catalyse the growth of regular ice. Our study not only highlights the active role of defects in nucleation but also suggests that the traditional concept of lattice match between a nucleation centre and crystalline lattice should be extended to include a broader match with metastable, non-crystalline structural motifs.

A hormone-related female anti-aphrodisiac signals temporary infertility and causes sexual abstinence to synchronize parental care.

PubMed

Engel, Katharina C; Stökl, Johannes; Schweizer, Rebecca; Vogel, Heiko; Ayasse, Manfred; Ruther, Joachim; Steiger, Sandra

2016-03-22

The high energetic demand of parental care requires parents to direct their resources towards the support of existing offspring rather than investing into the production of additional young. However, how such a resource flow is channelled appropriately is poorly understood. In this study, we provide the first comprehensive analysis of the physiological mechanisms coordinating parental and mating effort in an insect exhibiting biparental care. We show a hormone-mediated infertility in female burying beetles during the time the current offspring is needy and report that this temporary infertility is communicated via a pheromone to the male partner, where it inhibits copulation. A shared pathway of hormone and pheromone system ensures the reliability of the anti-aphrodisiac. Female infertility and male sexual abstinence provide for the concerted investment of parental resources into the existing developing young. Our study thus contributes to our deeper understanding of the mechanisms underlying adaptive parental decisions.

Understanding asexual identity as a means to facilitate culturally competent care: A systematic literature review.

PubMed

Jones, Catriona; Hayter, Mark; Jomeen, Julie

2017-12-01

To provide a contemporary overview of asexuality and the implications this has for healthcare practice. Individuals belonging to sexual minority groups face many barriers in accessing appropriate health care. The term "sexual minority group" is usually used to refer to lesbian women, gay, bisexual and transgender individuals. Anecdotal and research evidence suggests that those who identify as asexual have similar poor experiences. Systematic review and qualitative analysis. This work uses a systematic review and qualitative analysis of the existing interview data from self-identified asexuals, to construct features of the asexual identity. The findings will help practitioners and health professionals develop an understanding of this poorly understood construct. Ultimately this work is aimed at facilitating culturally competent care in the context of asexuality. Qualitative analysis produced three themes, which can be used, not only to frame asexuality in a positive and normalising way, but also to provide greater understanding of asexuality, "romantic differences coupled with sexual indifference," "validation through engagement with asexual communities" and "a diversity of subasexual identities." Having some understanding of what it means to identify as asexual, and respecting the choices made by asexuals can markedly improve the experiences of those who embrace an asexual identity when engaging with health care. Anecdotal evidence, taken from one of the largest asexual online forums, suggests that a number of self-identified asexuals choose not to disclose their identity to healthcare professionals through fear of their asexual status being pathologised, problematised or judged. Given that asexuality is a poorly understood concept, this may be due to lack of understanding on behalf of healthcare providers. The review provides health professionals and practitioners working in clinical settings with some insights of the features of an asexual identity to facilitate culturally competent care. © 2017 John Wiley & Sons Ltd.

Sources of heavy metals in urban wastewater in Stockholm.

PubMed

Sörme, L; Lagerkvist, R

2002-10-21

The sources of heavy metals to a wastewater treatment plant was investigated. Sources can be actual goods, e.g. runoff from roofs, wear of tires, food, or activities, e.g. large enterprises, car washes. The sources were identified by knowing the metals content in various goods and the emissions from goods to sewage or stormwater. The sources of sewage water and stormwater were categorized to enable comparison with other research and measurements. The categories were households, drainage water, businesses, pipe sediment (all transported in sewage water), atmospheric deposition, traffic, building materials and pipe sediment (transported in stormwater). Results show that it was possible to track the sources of heavy metals for some metals such as Cu and Zn (110 and 100% found, respectively) as well as Ni and Hg (70% found). Other metals sources are still poorly understood or underestimated (Cd 60%, Pb 50%, Cr 20% known). The largest sources of Cu were tap water and roofs. For Zn the largest sources were galvanized material and car washes. In the case of Ni, the largest sources were chemicals used in the WTP and drinking water itself. And finally, for Hg the most dominant emission source was the amalgam in teeth. For Pb, Cr and Cd, where sources were more poorly understood, the largest contributors for all were car washes. Estimated results of sources from this study were compared with previously done measurements. The comparison shows that measured contribution from households is higher than that estimated (except Hg), leading to the conclusion that the sources of sewage water from households are still poorly understood or that known sources are underestimated. In the case of stormwater, the estimated contributions are rather well in agreement with measured contributions, although uncertainties are large for both estimations and measurements. Existing pipe sediments in the plumbing system, which release Hg and Pb, could be one explanation for the missing amount of these metals. Large enterprises were found to make a very small contribution, 4% or less for all metals studied. Smaller enterprises (with the exception of car washes) have been shown to make a small contribution in another city; the contribution in this case study is still unknown.

Atmospheric Research at BNL

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

Peter Daum

2008-10-06

Brookhaven researcher Peter Daum discusses an international field experiment designed to make observations of critical components of the climate system of the southeastern Pacific. Because elements of this system are poorly understood and poorly represent

Atmospheric Research at BNL

ScienceCinema

Peter Daum

2017-12-09

Brookhaven researcher Peter Daum discusses an international field experiment designed to make observations of critical components of the climate system of the southeastern Pacific. Because elements of this system are poorly understood and poorly represent

Exercising arrhythmias and sudden cardiac death in horses: Review of the literature and comparative aspects.

PubMed

Navas de Solis, C

2016-07-01

Arrhythmias are common in equine athletes during and immediately after exercise. Many of these rhythm variations are not clinically relevant. In horses, a link between different exercising arrhythmias and poor performance or between exercising arrhythmias and sudden cardiac death (SCD) is strongly suspected but not fully understood or proven. SCD during races or competitions is rare, but has catastrophic consequences for the safety of the human partner and public perceptions of welfare during equestrian sports. This review summarises current knowledge of equine exercise arrhythmias and their implications in SCD and compares existing principles and recommendations for equine subjects with those for human athletes. © 2016 EVJ Ltd.

Interplay of DNA repair with transcription: from structures to mechanisms.

PubMed

Deaconescu, Alexandra M; Artsimovitch, Irina; Grigorieff, Nikolaus

2012-12-01

Many DNA transactions are crucial for maintaining genomic integrity and faithful transfer of genetic information but remain poorly understood. An example is the interplay between nucleotide excision repair (NER) and transcription, also known as transcription-coupled DNA repair (TCR). Discovered decades ago, the mechanisms for TCR have remained elusive, not in small part due to the scarcity of structural studies of key players. Here we summarize recent structural information on NER/TCR factors, focusing on bacterial systems, and integrate it with existing genetic, biochemical, and biophysical data to delineate the mechanisms at play. We also review emerging, alternative modalities for recruitment of NER proteins to DNA lesions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Reactive Granulomatous Dermatitis: A Review of Palisaded Neutrophilic and Granulomatous Dermatitis, Interstitial Granulomatous Dermatitis, Interstitial Granulomatous Drug Reaction, and a Proposed Reclassification.

PubMed

Rosenbach, Misha; English, Joseph C

2015-07-01

The terms "palisaded neutrophilic and granulomatous dermatitis," "interstitial granulomatous dermatitis," and the subset "interstitial granulomatous drug reaction" are a source of confusion. There exists substantial overlap among the entities with few strict distinguishing features. We review the literature and highlight areas of distinction and overlap, and propose a streamlined diagnostic workup for patients presenting with this cutaneous reaction pattern. Because the systemic disease associations and requisite workup are similar, and the etiopathogenesis is poorly understood but likely similar among these entities, we propose the simplified unifying term "reactive granulomatous dermatitis" to encompass these entities. Copyright © 2015 Elsevier Inc. All rights reserved.

Main magnetic field of Jupiter and its implications for future orbiter missions

NASA Technical Reports Server (NTRS)

Acuna, M. H.; Ness, N. F.

1975-01-01

A very strong planetary magnetic field and an enormous magnetosphere with extremely intense radiation belts exist at Jupiter. Pioneer 10 and 11 fly-bys confirmed and extended the earlier ground based estimates of many of these characteristics but left unanswered or added to the list of several important and poorly understood features: the source mechanism and location of decametric emissions, and the absorption effects by the natural satellites Amalthea, Io, Europa and Ganymede. High inclination orbits (exceeding 60 deg) with low periapses (less than 2 Jupiter radii) are required to map the radiation belts and main magnetic field of Jupiter accurately so as to permit full investigation of these and associated phenomena.

Anatomy of a Jam

NASA Astrophysics Data System (ADS)

Tang, Junyao; Sagdighpour, Sepehr; Behringer, Robert

2008-11-01

Flow in a hopper is both a fertile testing ground for understanding models for granular flow and industrially highly relevant. However, the formation of arches in the hopper opening, which halts the hopper flow unpredictably, is still poorly understood. In this work, we conduct a two-dimension hopper experiments, using photoelastic particles, and characterize these experiments in terms of a statistical model that considers the probability of jamming. The distribution of the hopper flow times exhibits an exponential decay, which shows the existence of a characteristic ``mean flow time.'' We then conduct further experiments to examine the connection between the mean flow time, the hopper geometry, the local density, and geometric structures and forces at the particle scale.

Chronic Wound Repair and Healing in Older Adults: Current Status and Future Research

PubMed Central

Gould, Lisa; Abadir, Peter; Brem, Harold; Carter, Marissa; Conner-Kerr, Teresa; Davidson, Jeff; DiPietro, Luisa; Falanga, Vincent; Fife, Caroline; Gardner, Sue; Grice, Elizabeth; Harmon, John; Hazzard, William R.; High, Kevin P.; Houghton, Pamela; Jacobson, Nasreen; Kirsner, Robert S.; Kovacs, Elizabeth J.; Margolish, David; McFarland Horne, Frances; Reed, May J.; Sullivan, Dennis H.; Thom, Stephen; Tomic-Canic, Marjana; Walston, Jeremy; Whitney, JoAnne; Williams, John; Zieman, Susan; Schmader, Kenneth

2014-01-01

The incidence of chronic wounds is increased among older adults, and the impact of chronic wounds on quality of life is particularly profound in this population. It is well established that wound healing slows with age. However, the basic biology underlying chronic wounds and the influence of age-associated changes on wound healing are poorly understood. Most studies have used in vitro approaches and various animal models, but observed changes translate poorly to human healing conditions. The impact of age and accompanying multi-morbidity on the effectiveness of existing and emerging treatment approaches for chronic wounds is also unknown, and older adults tend to be excluded from randomized clinical trials. Poorly defined outcomes and variables, lack of standardization in data collection, and variations in the definition, measurement, and treatment of wounds also hamper clinical studies. The Association of Specialty Professors, in conjunction with the National Institute on Aging and the Wound Healing Society, held a workshop, summarized in this paper, to explore the current state of knowledge and research challenges, engage investigators across disciplines, and identify key research questions to guide future study of age-associated changes in chronic wound healing. PMID:25486905

Chronic Wound Repair and Healing in Older Adults: Current Status and Future Research

PubMed Central

Gould, Lisa; Abadir, Peter; Brem, Harold; Carter, Marissa; Conner-Kerr, Teresa; Davidson, Jeff; DiPietro, Luisa; Falanga, Vincent; Fife, Caroline; Gardner, Sue; Grice, Elizabeth; Harmon, John; Hazzard, William R.; High, Kevin P.; Houghton, Pamela; Jacobson, Nasreen; Kirsner, Robert S.; Kovacs, Elizabeth J.; Margolis, David; Horne, Frances McFarland; Reed, May J.; Sullivan, Dennis H.; Thom, Stephen; Tomic-Canic, Marjana; Walston, Jeremy; Whitney, Jo Anne; Williams, John; Zieman, Susan; Schmader, Kenneth

2015-01-01

Older adults are more likely to have chronic wounds than younger people, and the effect of chronic wounds on quality of life is particularly profound in this population. Wound healing slows with age, but the basic biology underlying chronic wounds and the influence of age-associated changes on wound healing are poorly understood. Most studies have used in vitro approaches and various animal models, but observed changes translate poorly to human healing conditions. The effect of age and accompanying multimorbidity on the effectiveness of existing and emerging treatment approaches for chronic wounds is also unknown, and older adults tend to be excluded from randomized clinical trials. Poorly defined outcomes and variables; lack of standardization in data collection; and variations in the definition, measurement, and treatment of wounds also hamper clinical studies. The Association of Specialty Professors, in conjunction with the National Institute on Aging and the Wound Healing Society, held a workshop, summarized in this article, to explore the current state of knowledge and research challenges, engage investigators across disciplines, and identify research questions to guide future study of age-associated changes in chronic wound healing. PMID:25753048

The Evolution of the Data Scientist.

NASA Astrophysics Data System (ADS)

Parsons, M. A.

2011-12-01

When did the data scientist come into being? The National Science Board formally defined the term in 2005. Prior to that, the term was used sporadically, but typically to refer to statisticians or analysts. Nevertheless, the data scientist function has existed for a long time. Those who performed the function were called data managers or librarians or curators. Their role with digital data was critical but ill defined and poorly understood, especially by outsiders. Today, the tem data scientist is gaining currency and the discipline is gaining prominence, but it is a very dynamic field. And while it may be better defined, the term is still poorly understood. This lack of understanding can partly be attributed to the dynamic and evolutionary nature of the field. Domain scientists have developed new expectations for technology and services that enhance their ability to handle massive and complex data and present new challenges to data scientists. In response, data scientists are redefining and adapting their role to these rapidly changing demands of data-driven science and the fourth paradigm. In this paper, I explore the recent evolution of the field of data science as a socio-technical discipline. I discuss what has changed as well as what has remained the same and how some things that seem new may be a recasting of old problems. I take the view that data science is necessarily an evolutionary field that will need to continue to adapt in response to known and unknown challenges in order to ensure a healthy data ecosystem.

Measuring and modeling polymer concentration profiles near spindle boundaries argues that spindle microtubules regulate their own nucleation

NASA Astrophysics Data System (ADS)

Kaye, Bryan; Stiehl, Olivia; Foster, Peter J.; Shelley, Michael J.; Needleman, Daniel J.; Fürthauer, Sebastian

2018-05-01

Spindles are self-organized microtubule-based structures that segregate chromosomes during cell division. The mass of the spindle is controlled by the balance between microtubule turnover and nucleation. The mechanisms that control the spatial regulation of microtubule nucleation remain poorly understood. While previous work found that microtubule nucleators bind to pre-existing microtubules in the spindle, it is still unclear whether this binding regulates the activity of those nucleators. Here we use a combination of experiments and mathematical modeling to investigate this issue. We measured the concentration of microtubules and soluble tubulin in and around the spindle. We found a very sharp decay in the concentration of microtubules at the spindle interface. This is inconsistent with a model in which the activity of nucleators is independent of their association with microtubules but consistent with a model in which microtubule nucleators are only active when bound to pre-existing microtubules. This argues that the activity of microtubule nucleators is greatly enhanced when bound to pre-existing microtubules. Thus, microtubule nucleators are both localized and activated by the microtubules they generate.

Unraveling navigational strategies in migratory insects

PubMed Central

Merlin, Christine; Heinze, Stanley; Reppert, Steven M.

2011-01-01

Long-distance migration is a strategy some animals use to survive a seasonally changing environment. To reach favorable grounds, migratory animals have evolved sophisticated navigational mechanisms that rely on a map and compasses. In migratory insects, the existence of a map sense (sense of position) remains poorly understood, but recent work has provided new insights into the mechanisms some compasses use for maintaining a constant bearing during long-distance navigation. The best-studied directional strategy relies on a time-compensated sun compass, used by diurnal insects, for which neural circuits have begun to be delineated. Yet, a growing body of evidence suggests that migratory insects may also rely on other compasses that use night sky cues or the Earth's magnetic field. Those mechanisms are ripe for exploration. PMID:22154565

Joint Stability in Total Knee Arthroplasty: What Is the Target for a Stable Knee?

PubMed

Wright, Timothy M

2017-02-01

Instability remains a common cause of failure in total knee arthroplasty. Although approaches for surgical treatment of instability exist, the target for initial stability remains elusive, increasing the likelihood that failures will persist because adequate stability is not restored when performing the primary arthroplasty. Although the mechanisms that stabilize the knee joint-contact between the articular surfaces, ligamentous constraints, and muscle forces-are well-defined, their relative importance and the interplay among them throughout functions of daily living are poorly understood. The problem is exacerbated by the complex multiplanar motions that occur across the joint and the large variations in these motions across the population, suggesting that stability targets may need to be patient-specific.

Human casualties in earthquakes: Modelling and mitigation

USGS Publications Warehouse

Spence, R.J.S.; So, E.K.M.

2011-01-01

Earthquake risk modelling is needed for the planning of post-event emergency operations, for the development of insurance schemes, for the planning of mitigation measures in the existing building stock, and for the development of appropriate building regulations; in all of these applications estimates of casualty numbers are essential. But there are many questions about casualty estimation which are still poorly understood. These questions relate to the causes and nature of the injuries and deaths, and the extent to which they can be quantified. This paper looks at the evidence on these questions from recent studies. It then reviews casualty estimation models available, and finally compares the performance of some casualty models in making rapid post-event casualty estimates in recent earthquakes.

Multiplex engineering of industrial yeast genomes using CRISPRm.

PubMed

Ryan, Owen W; Cate, Jamie H D

2014-01-01

Global demand has driven the use of industrial strains of the yeast Saccharomyces cerevisiae for large-scale production of biofuels and renewable chemicals. However, the genetic basis of desired domestication traits is poorly understood because robust genetic tools do not exist for industrial hosts. We present an efficient, marker-free, high-throughput, and multiplexed genome editing platform for industrial strains of S. cerevisiae that uses plasmid-based expression of the CRISPR/Cas9 endonuclease and multiple ribozyme-protected single guide RNAs. With this multiplex CRISPR (CRISPRm) system, it is possible to integrate DNA libraries into the chromosome for evolution experiments, and to engineer multiple loci simultaneously. The CRISPRm tools should therefore find use in many higher-order synthetic biology applications to accelerate improvements in industrial microorganisms.

A primitive protostegid from Australia and early sea turtle evolution

PubMed Central

Kear, Benjamin P; Lee, Michael S.Y

2005-01-01

Sea turtles (Chelonioidea) are a prominent group of modern marine reptiles whose early history is poorly understood. Analysis of exceptionally well preserved fossils of Bouliachelys suteri gen. et sp. nov., a large-bodied basal protostegid (primitive chelonioid) from the Early Cretaceous (Albian) of Australia, indicates that early sea turtles were both larger and more diverse than previously thought. The analysis implies at least five distinct sea turtle lineages existed around 100 million years ago. Currently, the postcranially primitive Ctenochelys and Toxochelys are interpreted as crown-group sea turtles closely related to living cheloniids (e.g. Chelonia); in contrast, the new phylogeny suggests that they are transitional (intermediate stem-taxa) between continental testudines and derived, pelagic chelonioids. PMID:17148342

The effect of wind mixing on the vertical distribution of buoyant plastic debris

NASA Astrophysics Data System (ADS)

Kukulka, T.; Proskurowski, G.; Morét-Ferguson, S.; Meyer, D. W.; Law, K. L.

2012-04-01

Micro-plastic marine debris is widely distributed in vast regions of the subtropical gyres and has emerged as a major open ocean pollutant. The fate and transport of plastic marine debris is governed by poorly understood geophysical processes, such as ocean mixing within the surface boundary layer. Based on profile observations and a one-dimensional column model, we demonstrate that plastic debris is vertically distributed within the upper water column due to wind-driven mixing. These results suggest that total oceanic plastics concentrations are significantly underestimated by traditional surface measurements, requiring a reinterpretation of existing plastic marine debris data sets. A geophysical approach must be taken in order to properly quantify and manage this form of marine pollution.

The sopite syndrome revisited: Drowsiness and mood changes during real or apparent motion

NASA Astrophysics Data System (ADS)

Lawson, B. D.; Mead, A. M.

The sopite syndrome is a poorly understood response to motion. Drowsiness and mood changes are the primary characteristics of the syndrome. The sopite syndrome can exist in isolation from more apparent symptoms such as nausea, can last long; after nausea has subsided, and can debilitate some individuals. It is most likely a distinct syndrome from "regular" motion sickness or common fatigue, and is of potential concern in a variety of situations. The syndrome may be particularly hazardous in transportation settings where other performance challenges (e.g., sleep deprivation) are already present. It is also a potential concern in cases where illnesses such as sleep disorders or depression may interact with the syndrome and confuse diagnosis.

Zoonotic Transmission of Waterborne Disease: A Mathematical Model.

PubMed

Waters, Edward K; Hamilton, Andrew J; Sidhu, Harvinder S; Sidhu, Leesa A; Dunbar, Michelle

2016-01-01

Waterborne parasites that infect both humans and animals are common causes of diarrhoeal illness, but the relative importance of transmission between humans and animals and vice versa remains poorly understood. Transmission of infection from animals to humans via environmental reservoirs, such as water sources, has attracted attention as a potential source of endemic and epidemic infections, but existing mathematical models of waterborne disease transmission have limitations for studying this phenomenon, as they only consider contamination of environmental reservoirs by humans. This paper develops a mathematical model that represents the transmission of waterborne parasites within and between both animal and human populations. It also improves upon existing models by including animal contamination of water sources explicitly. Linear stability analysis and simulation results, using realistic parameter values to describe Giardia transmission in rural Australia, show that endemic infection of an animal host with zoonotic protozoa can result in endemic infection in human hosts, even in the absence of person-to-person transmission. These results imply that zoonotic transmission via environmental reservoirs is important.

Research Review: The Neurobiology and Genetics of Maltreatment and Adversity

ERIC Educational Resources Information Center

McCrory, Eamon; De Brito, Stephane A.; Viding, Essi

2010-01-01

The neurobiological mechanisms by which childhood maltreatment heightens vulnerability to psychopathology remain poorly understood. It is likely that a complex interaction between environmental experiences (including poor caregiving) and an individual's genetic make-up influence neurobiological development across infancy and childhood, which in…

Should Social Value Obligations be Local or Global?

PubMed

Nayak, Rahul; Shah, Seema K

2017-02-01

According to prominent bioethics scholars and international guidelines, researchers and sponsors have obligations to ensure that the products of their research are reasonably available to research participants and their communities. In other words, the claim is that research is unethical unless it has local social value. In this article, we argue that the existing conception of reasonable availability should be replaced with a social value obligation that extends to the global poor (and not just research participants and host communities). To the extent the social value requirement has been understood as geographically constrained to the communities that host research and the countries that can afford the products of research, it has neglected to include the global poor as members of the relevant society. We argue that a new conception of social value obligations is needed for two reasons. First, duties of global beneficence give reason for researchers, sponsors, and institutions to take steps to make their products more widely accessible. Second, public commitments made by many institutions acknowledge and engender responsibilities to make the products of research more accessible to the global poor. Future research is needed to help researchers and sponsors discharge these obligations in ways that unlock their full potential. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Diversity and Ecology of Viruses in Hyperarid Desert Soils

PubMed Central

Zablocki, Olivier; Adriaenssens, Evelien M.

2015-01-01

In recent years, remarkable progress has been made in the field of virus environmental ecology. In marine ecosystems, for example, viruses are now thought to play pivotal roles in the biogeochemical cycling of nutrients and to be mediators of microbial evolution through horizontal gene transfer. The diversity and ecology of viruses in soils are poorly understood, but evidence supports the view that the diversity and ecology of viruses in soils differ substantially from those in aquatic systems. Desert biomes cover ∼33% of global land masses, and yet the diversity and roles of viruses in these dominant ecosystems remain poorly understood. There is evidence that hot hyperarid desert soils are characterized by high levels of bacterial lysogens and low extracellular virus counts. In contrast, cold desert soils contain high extracellular virus titers. We suggest that the prevalence of microbial biofilms in hyperarid soils, combined with extreme thermal regimens, exerts strong selection pressures on both temperate and virulent viruses. Many desert soil virus sequences show low values of identity to virus genomes in public databases, suggesting the existence of distinct and as-yet-uncharacterized soil phylogenetic lineages (e.g., cyanophages). We strongly advocate for amplification-free metavirome analyses while encouraging the classical isolation of phages from dominant and culturable microbial isolates in order to populate sequence databases. This review provides an overview of recent advances in the study of viruses in hyperarid soils and of the factors that contribute to viral abundance and diversity in hot and cold deserts and offers technical recommendations for future studies. PMID:26590289

NASA Aims to Create First-Ever Space-Based Sodium Lidar to Study Poorly Understood Mesosphere

NASA Image and Video Library

2017-12-08

Caption: Mike Krainak (left) and Diego Janches recently won NASA follow-on funding to advance a spaceborne sodium lidar needed to probe Earth’s poorly understood mesosphere. Credits: NASA/W. Hrybyk More: A team of NASA scientists and engineers now believes it can leverage recent advances in a greenhouse-detecting instrument to build the world’s first space-based sodium lidar to study Earth’s poorly understood mesosphere. Scientist Diego Janches and laser experts Mike Krainak and Tony Yu, all of whom work at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, are leading a research-and-development effort to further advance the sodium lidar, which the group plans to deploy on the International Space Station if it succeeds in proving its flightworthiness. Read more: go.nasa.gov/2rcGpSM NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Auditory Processing Disorders: Acquisition and Treatment

ERIC Educational Resources Information Center

Moore, David R.

2007-01-01

Auditory processing disorder (APD) describes a mixed and poorly understood listening problem characterised by poor speech perception, especially in challenging environments. APD may include an inherited component, and this may be major, but studies reviewed here of children with long-term otitis media with effusion (OME) provide strong evidence…

Dignity-based approaches in the care of terminally ill patients.

PubMed

Thompson, Genevieve N; Chochinov, Harvey M

2008-03-01

Promoting dignified dying is an altruistic goal in palliative care. Until recently, what was meant by this construct was poorly understood. This review seeks to clarify what is meant by dignity at the end of life, what threatens dignity, and evidence of the domains that define dignity. A model of dignity is proposed from which interventions can be derived. A paucity of research exists exploring the concept of dignity. What can be gleaned from this work is that dignity is socially constructed and mediated in our relationships with others. Research has noted that self-perceived burden, depression, hopelessness, and 'the reflection patients see of themselves in the eye of the beholder' are intimately connected to one's notion of dignity. A model of dignity in the terminally ill has been developed that outlines three areas that are most influential in shaping dignity. Interventions such as dignity therapy and critical personal reflection are proposed as tools to promote dignity. Despite the fact that little research exists exploring the notion of dignity at the end of life, a robust model of dignity exists and is helpful in directing interventions aimed at improving care at the end of life.

Unraveling navigational strategies in migratory insects.

PubMed

Merlin, Christine; Heinze, Stanley; Reppert, Steven M

2012-04-01

Long-distance migration is a strategy some animals use to survive a seasonally changing environment. To reach favorable grounds, migratory animals have evolved sophisticated navigational mechanisms that rely on a map and compasses. In migratory insects, the existence of a map sense (sense of position) remains poorly understood, but recent work has provided new insights into the mechanisms some compasses use for maintaining a constant bearing during long-distance navigation. The best-studied directional strategy relies on a time-compensated sun compass, used by diurnal insects, for which neural circuits have begun to be delineated. Yet, a growing body of evidence suggests that migratory insects may also rely on other compasses that use night sky cues or the Earth's magnetic field. Those mechanisms are ripe for exploration. Copyright © 2011 Elsevier Ltd. All rights reserved.

Silencing of ATP11B by RNAi-Induced Changes in Neural Stem Cell Morphology.

PubMed

Wang, Jiao; Wang, Qian; Zhou, Fangfang; Wang, Dong; Wen, Tieqiao

2017-01-01

RNA interference (RNAi) technology is one of the main research tools in many studies of neural stem cells. This study describes effects of ATP11B on the morphology change of neural stem cells by using RNAi. ATP11B belongs to P4-ATPases family, which is preferential translocate phosphatidylserine of cell membrane. Although it exists in neural stem cells, its physiological function is poorly understood. By using RNAi technology to downregulate expression of ATP11B, we found distinct morphological changes in neural stem cells. More important, psiRNA-ATP11B-transfected cells displayed short neurite outgrowth compared to the control cells. These data strongly suggest that ATP11B plays a key role in the morphological change of neural stem cells.

Emergency warning for people with disabilities.

PubMed

Putkovich, Kenneth

2013-01-01

The intent of this article is to assess the current state of Emergency Warning capabilities in the United States and make recommendations on what needs to be done to cost effectively establish a National Emergency Warning System to best serve the people of the United States, including those with disabilities. As part of this assessment, terminology will be defined, existing systems will be examined, critical needs and functions will be explained, and recommendations made for a system to deliver emergency messages to those people immediately at risk from natural and human-caused disasters in a timely and effective manner, regardless of location or situational circumstance. The assessment will include the needs and available technologies for delivering emergency warnings to people with disabilities, which are generally little understood, poorly addressed, and often ignored.

Role of a new Rho family member in cell migration and axon guidance in C. elegans.

PubMed

Zipkin, I D; Kindt, R M; Kenyon, C J

1997-09-05

Rho family GTPases are thought to regulate actin-dependent processes, but their functions in vivo are still poorly understood. We have investigated the function of a new, widely expressed Rho family member in C. elegans by analyzing mutations in the endogenous gene. Activated and null alleles all inhibit cell migration, demonstrating that this protein is required for cell migration in vivo. Only a small subset of the migrations inhibited by activating mutations are inhibited by null mutations, suggesting that considerable functional redundancy exists within this system. Our findings support this conclusion and show that mig-2 functions redundantly with another pathway to regulate nuclear migration. Surprisingly, activated alleles also cause misguided axon growth, suggesting that Rho family GTPases may couple guidance cues to process outgrowth.

Dynamic void behavior in polymerizing polymethyl methacrylate cement.

PubMed

Muller, Scott D; McCaskie, Andrew W

2006-02-01

Cement mantle voids remain controversial with respect to survival of total hip arthroplasty. Void evolution is poorly understood, and attempts at void manipulation can only be empirical. We induced voids in a cement model simulating the constraints of the proximal femur. Intravoid pressure and temperature were recorded throughout polymerization, and the initial and final void volumes were measured. Temperature-dependent peak intravoid pressures and void volume increases were observed. After solidification, subatmospheric intravoid pressures were observed. The magnitude of these observations could not be explained by the ideal gas law. Partial pressures of the void gas at peak pressures demonstrated a dominant effect of gaseous monomer, thereby suggesting that void growth is a pressure-driven phenomenon resulting from temperature-dependent evaporation of monomer into existing trapped air voids.

Tropical forests and global change: filling knowledge gaps.

PubMed

Zuidema, Pieter A; Baker, Patrick J; Groenendijk, Peter; Schippers, Peter; van der Sleen, Peter; Vlam, Mart; Sterck, Frank

2013-08-01

Tropical forests will experience major changes in environmental conditions this century. Understanding their responses to such changes is crucial to predicting global carbon cycling. Important knowledge gaps exist: the causes of recent changes in tropical forest dynamics remain unclear and the responses of entire tropical trees to environmental changes are poorly understood. In this Opinion article, we argue that filling these knowledge gaps requires a new research strategy, one that focuses on trees instead of leaves or communities, on long-term instead of short-term changes, and on understanding mechanisms instead of documenting changes. We propose the use of tree-ring analyses, stable-isotope analyses, manipulative field experiments, and well-validated simulation models to improve predictions of forest responses to global change. Copyright © 2013 Elsevier Ltd. All rights reserved.

Neurotoxicology of the Brain Barrier System: New Implications

PubMed Central

Zheng, Wei

2014-01-01

The concept of a barrier system in the brain has existed for nearly a century. The barrier that separates the blood from the cerebral interstitial fluid is defined as the blood-brain barrier, while the one that discontinues the circulation between the blood and cerebrospinal fluid is named the blood-cerebrospinal fluid barrier. Evidence in the past decades suggests that brain barriers are subject to toxic insults from neurotoxic chemicals circulating in blood. The aging process and some disease states render barriers more vulnerable to insults arising inside and outside the barriers. The implication of brain barriers in certain neurodegenerative diseases is compelling, although the contribution of chemical-induced barrier dysfunction in the etiology of any of these disorders remains poorly understood. This review examines what is currently understood about brain barrier systems in central nervous system disorders by focusing on chemical-induced neurotoxicities including those associated with nitrobenzenes, N-methyl-D-aspartate, cyclosporin A, pyridostigmine bromide, aluminum, lead, manganese, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and 3-nitropropionic acid. Contemporary research questions arising from this growing understanding show enormous promises for brain researchers, toxicologists, and clinicians. PMID:11778669

"Nobody came to help": interviews with women convicted of filicide in Malaysia.

PubMed

Razali, Salmi; Fisher, Jane; Kirkman, Maggie

2018-03-22

Although filicide is of serious concern, it is poorly understood in Malaysia. Our interviews with health and policy professionals revealed that they attribute responsibility for filicide to women's failure to comply with social norms and religious teachings. This research sought to understand the meaning of and background to filicide from the perspectives of women who have been convicted of filicide in Malaysia. In-depth interviews were conducted in person with all eligible and consenting women convicted of filicide and incarcerated in prisons or forensic psychiatric institutions. Women's accounts were translated into English and analysed using interpretative phenomenological analysis and interpreted using narrative theory. Interviews with nine women convicted of filicide yielded evidence that others were implicated in the crime but punished less severely, if at all, and that the women had experienced lifelong gender-based violence and marginalisation with minimal access to health and social care. These findings illuminate an inadequately understood phenomenon in Malaysia and reveal why existing strategies to reduce filicide, which reflect key stakeholders' views, have had little impact. They reveal the pervasive harm of violence against women and children and its link to filicide.

Collective arrangements and social networks: Coping strategies for the poor households in the Great Ruaha Catchment in Tanzania

NASA Astrophysics Data System (ADS)

Kadigi, Reuben M. J.; Mdoe, N. S. Y.; Ashimogo, G. C.

Access to water and land resources underpins the socio-economic fabric of many societies in the Southern Africa region, which is characterized broadly as underdeveloped with widespread food insecurity, exacerbated by persistent droughts, erratic rainfalls and increasing human populations. The availability of land and water resources is increasingly diminishing and becoming a stumbling block to the development of the agrarian societies in the region. The poor households have in turn adopted new livelihood coping mechanisms but little research has been done to assess the effectiveness of these ‘instruments’. Consequently, the concepts of sustainable water resources management and agricultural development have remained elusive and poorly understood by policy makers as well as by water resources planners and managers. Recognizing this, a study was conducted between 2002 and 2005 under the RIPARWIN (Raising Irrigation Productivity and Releasing Water for Intersectoral Needs) project to assess the spatial dynamics of livelihood capital, vulnerability and coping strategies for the poor agrarian households in the Upper Great Ruaha River Catchment (GRRC) in Tanzania. The results of analysis showed an array of livelihood platforms and institutional contexts that act to shape the existing livelihood typologies in the GRRC. In addition, the results showed a gradual increase in household vulnerability from upstream to downstream, particularly in terms of access to physical and natural assets. Vulnerability was found to be directly associated with the number of dependants. The female-headed households were relatively more likely to be vulnerable than the male-headed households (cf. probabilities of 27% and 21%, respectively). The value of collective arrangements and drawing on social networks crosscut all social strata and ranked as the most common livelihood strategy. This suggests that the scope for reducing vulnerability among the poor households in the GRRC critically depends on the existing institutional arrangements and mechanisms. Of paramount importance is perhaps the need to facilitate the establishment and empowerment of water use associations and apex bodies. In the study area, this appears to be promising enough to build ‘strong’ institutional platforms through which water and land resources would be managed sustainably.

Isotopic signals of summer denitrification in a northern hardwood forested catchment

Treesearch

Sarah K. Wexler; Christine L. Goodale; Kevin J. McGuire; Scott W. Bailey; Peter M. Groffman

2014-01-01

Despite decades of measurements, the nitrogen balance of temperate forest catchments remains poorly understood. Atmospheric nitrogen deposition often greatly exceeds streamwater nitrogen losses; the fate of the remaining nitrogen is highly uncertain. Gaseous losses of nitrogen to denitrification are especially poorly documented and are often ignored. Here, we provide...

Punishment and Welfare: Paternal Incarceration and Families' Receipt of Public Assistance

ERIC Educational Resources Information Center

Sugie, Naomi F.

2012-01-01

The United States criminal justice and welfare systems are two important government institutions in the lives of the poor. Despite many theoretical discussions about their relationship, their operation at the level of offenders and families remains poorly understood. This paper utilizes Fragile Families and Child Wellbeing data to examine how…

Experimental Investigation of Neutral Species from Micrometeoroid Bombardment

NASA Astrophysics Data System (ADS)

Collette, A.; Sternovsky, Z.; Rocha, J. R.; Munsat, T. L.; Horanyi, M.

2014-12-01

Surface-boundary exospheres exist in a balance between source and loss processes. An important area of uncertainty, highlighted by the MESSENGER observations of Mg and Ca at Mercury, and the recently concluded LADEE observations at the Moon, is the role of micrometeoroid bombardment as a source process for liberating surface species. Unlike sputtering or photon stimulated desorption processes, the physics of micrometeoroid impacts are still poorly understood; in particular, no comprehensive model exists to predict partitioning of impact products between ejecta fragments, charged particles, and neutrals. We present initial experiments at the IMPACT dust accelerator facility (University of Colorado Boulder) aimed at directly measuring the fraction of neutral species liberated in micrometeoroid impacts. Simulated micrometeoroids (micron- and submicron-sized iron spheres) are fired at targets containing refractory elements, including fused silica (SiO2), sapphire (Al2O3), and magnesium fluoride (MgF2). Total quantities of specific impact-generated neutral species are measured using a mass spectrometer, as a function of impactor speed and mass, and compared with well-established scaling laws for charged particle production.

Widespread mixing and burial of Earth's Hadean crust by asteroid impacts.

PubMed

Marchi, S; Bottke, W F; Elkins-Tanton, L T; Bierhaus, M; Wuennemann, K; Morbidelli, A; Kring, D A

2014-07-31

The history of the Hadean Earth (∼4.0-4.5 billion years ago) is poorly understood because few known rocks are older than ∼3.8 billion years old. The main constraints from this era come from ancient submillimetre zircon grains. Some of these zircons date back to ∼4.4 billion years ago when the Moon, and presumably the Earth, was being pummelled by an enormous flux of extraterrestrial bodies. The magnitude and exact timing of these early terrestrial impacts, and their effects on crustal growth and evolution, are unknown. Here we provide a new bombardment model of the Hadean Earth that has been calibrated using existing lunar and terrestrial data. We find that the surface of the Hadean Earth was widely reprocessed by impacts through mixing and burial by impact-generated melt. This model may explain the age distribution of Hadean zircons and the absence of early terrestrial rocks. Existing oceans would have repeatedly boiled away into steam atmospheres as a result of large collisions as late as about 4 billion years ago.

Child maltreatment and pediatric asthma: a review of the literature.

PubMed

Schreier, Hannah M C; Chen, Edith; Miller, Gregory E

2016-01-01

Child maltreatment is a common problem with known adverse consequences, yet its contributions to the development and course of pediatric asthma are only poorly understood. This review first describes possible pathways connecting child maltreatment to pediatric asthma, including aspects of the physical home environment, health behaviors and disease management, and psychological consequences of child maltreatment. We subsequently review existing studies, which generally report an association between maltreatment experiences and asthma outcomes in childhood. However, this literature is in its early stages; there are only a handful studies, most of them rely on self-reports of both child maltreatment and asthma history, and none have investigated the physiological underpinnings of this association. Taken together, however, the studies are suggestive of child maltreatment playing a role in pediatric asthma incidence and expression that should be explored further. Existing data are sparse and do not allow for specific conclusions. However, the data are suggestive of child maltreatment influencing asthma risk and morbidity long before the adult years. Future research should focus on understanding how child maltreatment contributes to asthma disease risk and progression in this highly vulnerable population.

Origin of anomalous inverse notch effect in bulk metallic glasses

NASA Astrophysics Data System (ADS)

Pan, J.; Zhou, H. F.; Wang, Z. T.; Li, Y.; Gao, H. J.

2015-11-01

Understanding notch-related failure is crucial for the design of reliable engineering structures. However, substantial controversies exist in the literature on the notch effect in bulk metallic glasses (BMGs), and the underlying physical mechanism responsible for the apparent confusion is still poorly understood. Here we investigate the physical origin of an inverse notch effect in a Zr-based metallic glass, where the tensile strength of the material is dramatically enhanced, rather than decreased (as expected from the stress concentration point of view), by introduction of a notch. Our experiments and molecular dynamics simulations show that the seemingly anomalous inverse notch effect is in fact caused by a transition in failure mechanism from shear banding at the notch tip to cavitation and void coalescence. Based on our theoretical analysis, the transition occurs as the stress triaxiality in the notched sample exceeds a material-dependent threshold value. Our results fill the gap in the current understanding of BMG strength and failure mechanism by resolving the conflicts on notch effects and may inspire re-interpretation of previous reports on BMG fracture toughness where pre-existing notches were routinely adopted.

Co-existence of Blau syndrome and NAID? Diagnostic challenges associated with presence of multiple pathogenic variants in NOD2 gene: a case report.

PubMed

Dziedzic, Magdalena; Marjańska, Agata; Bąbol-Pokora, Katarzyna; Urbańczyk, Anna; Grześk, Elżbieta; Młynarski, Wojciech; Kołtan, Sylwia

2017-07-27

Pediatric autoinflammatory diseases are rare and still poorly understood conditions resulting from defective genetic control of innate immune system, inter alia from anomalies of NOD2 gene. The product of this gene is Nod2 protein, taking part in maintenance of immune homeostasis. Clinical form of resultant autoinflammatory condition depends on NOD2 genotype; usually patients with NOD2 defects present with Blau syndrome, NOD2-associated autoinflammatory disease (NAID) or Crohn's disease. We present the case of a 7-year-old girl with co-existing symptoms of two rare diseases, Blau syndrome and NAID. Overlapping manifestations of two syndromes raised a significant diagnostic challenge, until next-generation molecular test (NGS) identified presence of three pathogenic variants of NOD2 gene: P268S, IVS8 +158 , 1007 fs, and established the ultimate diagnosis. Presence of multiple genetical abnormalities resulted in an ambiguous clinical presentation with overlapping symptoms of Blau syndrome and NAID. Final diagnosis of autoinflammatory disease opened new therapeutic possibilities, including the use of biological treatments.

Attitudes and norms affecting scientists’ data reuse

PubMed Central

Curty, Renata Gonçalves; Specht, Alison; Grant, Bruce W.; Dalton, Elizabeth D.

2017-01-01

The value of sharing scientific research data is widely appreciated, but factors that hinder or prompt the reuse of data remain poorly understood. Using the Theory of Reasoned Action, we test the relationship between the beliefs and attitudes of scientists towards data reuse, and their self-reported data reuse behaviour. To do so, we used existing responses to selected questions from a worldwide survey of scientists developed and administered by the DataONE Usability and Assessment Working Group (thus practicing data reuse ourselves). Results show that the perceived efficacy and efficiency of data reuse are strong predictors of reuse behaviour, and that the perceived importance of data reuse corresponds to greater reuse. Expressed lack of trust in existing data and perceived norms against data reuse were not found to be major impediments for reuse contrary to our expectations. We found that reported use of models and remotely-sensed data was associated with greater reuse. The results suggest that data reuse would be encouraged and normalized by demonstration of its value. We offer some theoretical and practical suggestions that could help to legitimize investment and policies in favor of data sharing. PMID:29281658

The Prospect of Market-Driven Improvements in Animal Welfare: Lessons from the Case of Grass Milk in Denmark

PubMed Central

Heerwagen, Lennart R.; Christensen, Tove; Sandøe, Peter

2013-01-01

Simple Summary Increased consumption of animal welfare-friendly products is suggested as one way of addressing public worries about the welfare of farm animals. However, the factors that drive and limit markets for animal welfare-friendly products are poorly understood. Based on an analysis of market for grass milk in Denmark, we conclude that successful cases of market-driven improvements in animal welfare require the joint presence of a number of positive drivers as well as low consumption barriers. Abstract Citizens in many European countries urge that the welfare of farm animals should be improved. Policy-makers propose that this could, at least to some extent, be achieved through increased consumption of animal products produced under labeling schemes guaranteeing higher standards of animal welfare. Yet considerable uncertainties exist about the ability of the market to promote animal welfare. So far the consumption of most welfare-friendly products has been limited, and the impact of driving and limiting factors is poorly understood. Reviewing market studies, we identify the factors that have shaped the relatively successful market for grass milk in Denmark. We conclude that the positive drivers such as an appealing animal welfare attribute and animal welfare being bundled with other qualities are essentially the same as those operating in connection with less successful animal welfare-friendly products. It is therefore to be expected that other animal welfare-friendly food products marketed via “natural behaviors” in the farm animals will catch the interest of consumers. However, grass milk consumption has been supported by proper labeling, ready availability and low price premiums as well as multifaceted public support. This suggests that successful cases require the joint presence of a number of positive drivers as well as low consumption barriers. PMID:26487414

Intensification of the Northeast Pacific oxygen minimum zone during the Bölling-Alleröd warm period

USGS Publications Warehouse

Zheng, Yen; van Geen, Alexander; Anderson, Robert F.; Gardner, James V.; Dean, Walter E.

2000-01-01

Although climate records from several locations around the world show nearly synchronous and abrupt changes, the nature of the inferred teleconnection is still poorly understood. On the basis of preserved laminations and molybdenum enrichments in open margin sediments we demonstrate that the oxygen content of northeast Pacific waters at 800 m depth during the Bölling-Alleröd warm period (15–13 kyr) was greatly reduced. Existing oxygen isotopic records of benthic and planktonic foraminifera suggest that this was probably due to suppressed ventilation at higher latitudes of the North Pacific. Comparison with ventilation records for the North Atlantic indicates an antiphased pattern of convection relative to the North Pacific over the past 22 kyr, perhaps due to variations in water vapor transport across Central America.

Conflicting health information: a critical research need.

PubMed

Carpenter, Delesha M; Geryk, Lorie L; Chen, Annie T; Nagler, Rebekah H; Dieckmann, Nathan F; Han, Paul K J

2016-12-01

Conflicting health information is increasing in amount and visibility, as evidenced most recently by the controversy surrounding the risks and benefits of childhood vaccinations. The mechanisms through which conflicting information affects individuals are poorly understood; thus, we are unprepared to help people process conflicting information when making important health decisions. In this viewpoint article, we describe this problem, summarize insights from the existing literature on the prevalence and effects of conflicting health information, and identify important knowledge gaps. We propose a working definition of conflicting health information and describe a conceptual typology to guide future research in this area. The typology classifies conflicting information according to four fundamental dimensions: the substantive issue under conflict, the number of conflicting sources (multiplicity), the degree of evidence heterogeneity and the degree of temporal inconsistency. © 2015 The Authors. Health Expectations Published by John Wiley & Sons Ltd.

THE DISCOVERY OF SOLAR-LIKE ACTIVITY CYCLES BEYOND THE END OF THE MAIN SEQUENCE?

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

Route, Matthew, E-mail: mroute@purdue.edu

2016-10-20

The long-term magnetic behavior of objects near the cooler end of the stellar main sequence is poorly understood. Most theoretical work on the generation of magnetism in these ultracool dwarfs (spectral type ≥M7 stars and brown dwarfs) suggests that their magnetic fields should not change in strength and direction. Using polarized radio emission measurements of their magnetic field orientations, I demonstrate that these cool, low-mass, fully convective objects appear to undergo magnetic polarity reversals analogous to those that occur on the Sun. This powerful new technique potentially indicates that the patterns of magnetic activity displayed by the Sun continue tomore » exist, despite the fully convective interiors of these objects, in contravention of several leading theories of the generation of magnetic fields by internal dynamos.« less

Protein-mediated looping of DNA under tension requires supercoiling

PubMed Central

Yan, Yan; Leng, Fenfei; Finzi, Laura; Dunlap, David

2018-01-01

Abstract Protein-mediated DNA looping is ubiquitous in chromatin organization and gene regulation, but to what extent supercoiling or nucleoid associated proteins promote looping is poorly understood. Using the lac repressor (LacI), a paradigmatic loop-mediating protein, we measured LacI-induced looping as a function of either supercoiling or the concentration of the HU protein, an abundant nucleoid protein in Escherichia coli. Negative supercoiling to physiological levels with magnetic tweezers easily drove the looping probability from 0 to 100% in single DNA molecules under slight tension that likely exists in vivo. In contrast, even saturating (micromolar) concentrations of HU could not raise the looping probability above 30% in similarly stretched DNA or 80% in DNA without tension. Negative supercoiling is required to induce significant looping of DNA under any appreciable tension. PMID:29365152

Contextual cueing: implicit learning and memory of visual context guides spatial attention.

PubMed

Chun, M M; Jiang, Y

1998-06-01

Global context plays an important, but poorly understood, role in visual tasks. This study demonstrates that a robust memory for visual context exists to guide spatial attention. Global context was operationalized as the spatial layout of objects in visual search displays. Half of the configurations were repeated across blocks throughout the entire session, and targets appeared within consistent locations in these arrays. Targets appearing in learned configurations were detected more quickly. This newly discovered form of search facilitation is termed contextual cueing. Contextual cueing is driven by incidentally learned associations between spatial configurations (context) and target locations. This benefit was obtained despite chance performance for recognizing the configurations, suggesting that the memory for context was implicit. The results show how implicit learning and memory of visual context can guide spatial attention towards task-relevant aspects of a scene.

Revealing the role of phospholipase Cβ3 in the regulation of VEGF-induced vascular permeability

PubMed Central

Hoeppner, Luke H.; Phoenix, Kathryn N.; Clark, Karl J.; Bhattacharya, Resham; Gong, Xun; Sciuto, Tracey E.; Vohra, Pawan; Suresh, Sandip; Bhattacharya, Santanu; Dvorak, Ann M.; Ekker, Stephen C.; Dvorak, Harold F.; Claffey, Kevin P.

2012-01-01

VEGF induces vascular permeability (VP) in ischemic diseases and cancer, leading to many pathophysiological consequences. The molecular mechanisms by which VEGF acts to induce hyperpermeability are poorly understood and in vivo models that easily facilitate real-time, genetic studies of VP do not exist. In the present study, we report a heat-inducible VEGF transgenic zebrafish (Danio rerio) model through which VP can be monitored in real time. Using this approach with morpholino-mediated gene knock-down and knockout mice, we describe a novel role of phospholipase Cβ3 as a negative regulator of VEGF-mediated VP by regulating intracellular Ca2+ release. Our results suggest an important effect of PLCβ3 on VP and provide a new model with which to identify genetic regulators of VP crucial to several disease processes. PMID:22674805

Developmental differences in auditory detection and localization of approaching vehicles.

PubMed

Barton, Benjamin K; Lew, Roger; Kovesdi, Casey; Cottrell, Nicholas D; Ulrich, Thomas

2013-04-01

Pedestrian safety is a significant problem in the United States, with thousands being injured each year. Multiple risk factors exist, but one poorly understood factor is pedestrians' ability to attend to vehicles using auditory cues. Auditory information in the pedestrian setting is increasing in importance with the growing number of quieter hybrid and all-electric vehicles on America's roadways that do not emit sound cues pedestrians expect from an approaching vehicle. Our study explored developmental differences in pedestrians' detection and localization of approaching vehicles. Fifty children ages 6-9 years, and 35 adults participated. Participants' performance varied significantly by age, and with increasing speed and direction of the vehicle's approach. Results underscore the importance of understanding children's and adults' use of auditory cues for pedestrian safety and highlight the need for further research. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ultrasonic Vocalizations Emitted by Flying Squirrels

PubMed Central

Murrant, Meghan N.; Bowman, Jeff; Garroway, Colin J.; Prinzen, Brian; Mayberry, Heather; Faure, Paul A.

2013-01-01

Anecdotal reports of ultrasound use by flying squirrels have existed for decades, yet there has been little detailed analysis of their vocalizations. Here we demonstrate that two species of flying squirrel emit ultrasonic vocalizations. We recorded vocalizations from northern (Glaucomys sabrinus) and southern (G. volans) flying squirrels calling in both the laboratory and at a field site in central Ontario, Canada. We demonstrate that flying squirrels produce ultrasonic emissions through recorded bursts of broadband noise and time-frequency structured frequency modulated (FM) vocalizations, some of which were purely ultrasonic. Squirrels emitted three types of ultrasonic calls in laboratory recordings and one type in the field. The variety of signals that were recorded suggest that flying squirrels may use ultrasonic vocalizations to transfer information. Thus, vocalizations may be an important, although still poorly understood, aspect of flying squirrel social biology. PMID:24009728

Algorithms in the historical emergence of word senses.

PubMed

Ramiro, Christian; Srinivasan, Mahesh; Malt, Barbara C; Xu, Yang

2018-03-06

Human language relies on a finite lexicon to express a potentially infinite set of ideas. A key result of this tension is that words acquire novel senses over time. However, the cognitive processes that underlie the historical emergence of new word senses are poorly understood. Here, we present a computational framework that formalizes competing views of how new senses of a word might emerge by attaching to existing senses of the word. We test the ability of the models to predict the temporal order in which the senses of individual words have emerged, using an historical lexicon of English spanning the past millennium. Our findings suggest that word senses emerge in predictable ways, following an historical path that reflects cognitive efficiency, predominantly through a process of nearest-neighbor chaining. Our work contributes a formal account of the generative processes that underlie lexical evolution.

The Small Acceptance Vertex Detector of NA61/SHINE

NASA Astrophysics Data System (ADS)

Deveaux, M.; Aduszkiewicz, A.; Ali, Y.; Baszczyk, M.; Brylinski, W.; Dorosz, P.; Di Luise, S.; Feofilov, G.; Gazdzicki, M.; Igolkin, S.; Jablonski, M.; Kovalenko, V.; Koziel, M.; Kucewicz, W.; Larsen, D.; Lazareva, T.; Martinengo, P.; Merzlaya, A.; Mik, L.; Planeta, R.; Snoch, A.; Vechernin, V.; Tefelski, D.; Suljic, M.; Staszel, P.

2018-02-01

Charmonium production in heavy ion collisions is considered as an important diagnostic probe for studying the phase diagram of strongly interacting matter for potential phase transitions. The interpretation of existing data from the CERN SPS is hampered by a lack of knowledge on the properties of open charm particle production in the fireball. Moreover, open charm production in heavy ion collisions by itself is poorly understood. To overcome this obstacle, the NA61/SHINE was equipped with a Small Acceptance Vertex Detector (SAVD), which is predicted to make the experiment sensitive to open charm mesons produced in A-A collisions at the SPS top energy. This paper will introduce the concept and the hardware of the SAVD. Moreover, first running experience as obtained in a commissioning run with a 150 AGeV/c Pb+Pb collision system will be reported.

Evolution of a sediment wave in an experimental channel

Treesearch

Thomas E. Lisle; James E. Pizzuto; Hiroshi Ikeda; Fujiko Iseya; Yoshinori Kodama

1997-01-01

Abstract - The routing of bed material through channels is poorly understood. We approach the problem by observing and modeling the fate of a low-amplitude sediment wave of poorly sorted sand that we introduced into an experimental channel transporting sediment identical to that of the introduced wave. The wave essentially dispersed upstream and downstream without...

Independent Learning--What We Do When You're Not There

ERIC Educational Resources Information Center

Hockings, Christine; Thomas, Liz; Ottaway, Jim; Jones, Rob

2018-01-01

Independent learning is one of the cornerstones of UK higher education yet it is poorly understood by students and is seen by politicians as a poor substitute for face to face teaching. This paper explores students' understandings, approaches and experiences of independent learning and how they may become more effective independent learners. This…

The role of bedrock groundwater in rainfall-runoff response at hillslope and catchment scales

Treesearch

C. Gabrielli; J.J. McDonnell; W.T. Jarvis

2012-01-01

Bedrock groundwater dynamics in headwater catchments are poorly understood and poorly characterized. Direct hydrometric measurements have been limited due to the logistical challenges associated with drilling through hard rock in steep, remote and often roadless terrain. We used a new portable bedrock drilling system to explore bedrock groundwater dynamics aimed at...

Global priorities for conservation across multiple dimensions of mammalian diversity

PubMed Central

Graham, Catherine H.; Costa, Gabriel C.; Hedges, S. Blair; Penone, Caterina; Radeloff, Volker C.; Rondinini, Carlo; Davidson, Ana D.

2017-01-01

Conservation priorities that are based on species distribution, endemism, and vulnerability may underrepresent biologically unique species as well as their functional roles and evolutionary histories. To ensure that priorities are biologically comprehensive, multiple dimensions of diversity must be considered. Further, understanding how the different dimensions relate to one another spatially is important for conservation prioritization, but the relationship remains poorly understood. Here, we use spatial conservation planning to (i) identify and compare priority regions for global mammal conservation across three key dimensions of biodiversity—taxonomic, phylogenetic, and traits—and (ii) determine the overlap of these regions with the locations of threatened species and existing protected areas. We show that priority areas for mammal conservation exhibit low overlap across the three dimensions, highlighting the need for an integrative approach for biodiversity conservation. Additionally, currently protected areas poorly represent the three dimensions of mammalian biodiversity. We identify areas of high conservation priority among and across the dimensions that should receive special attention for expanding the global protected area network. These high-priority areas, combined with areas of high priority for other taxonomic groups and with social, economic, and political considerations, provide a biological foundation for future conservation planning efforts. PMID:28674013

Global priorities for conservation across multiple dimensions of mammalian diversity.

PubMed

Brum, Fernanda T; Graham, Catherine H; Costa, Gabriel C; Hedges, S Blair; Penone, Caterina; Radeloff, Volker C; Rondinini, Carlo; Loyola, Rafael; Davidson, Ana D

2017-07-18

Conservation priorities that are based on species distribution, endemism, and vulnerability may underrepresent biologically unique species as well as their functional roles and evolutionary histories. To ensure that priorities are biologically comprehensive, multiple dimensions of diversity must be considered. Further, understanding how the different dimensions relate to one another spatially is important for conservation prioritization, but the relationship remains poorly understood. Here, we use spatial conservation planning to ( i ) identify and compare priority regions for global mammal conservation across three key dimensions of biodiversity-taxonomic, phylogenetic, and traits-and ( ii ) determine the overlap of these regions with the locations of threatened species and existing protected areas. We show that priority areas for mammal conservation exhibit low overlap across the three dimensions, highlighting the need for an integrative approach for biodiversity conservation. Additionally, currently protected areas poorly represent the three dimensions of mammalian biodiversity. We identify areas of high conservation priority among and across the dimensions that should receive special attention for expanding the global protected area network. These high-priority areas, combined with areas of high priority for other taxonomic groups and with social, economic, and political considerations, provide a biological foundation for future conservation planning efforts.

Acoustic measurement and morphological features of organic sediment deposits in combined sewer networks.

PubMed

Carnacina, Iacopo; Larrarte, Frédérique; Leonardi, Nicoletta

2017-04-01

The performance of sewer networks has important consequences from an environmental and social point of view. Poor functioning can result in flood risk and pollution at a large scale. Sediment deposits forming in sewer trunks might severely compromise the sewer line by affecting the flow field, reducing cross-sectional areas, and increasing roughness coefficients. In spite of numerous efforts, the morphological features of these depositional environments remain poorly understood. The interface between water and sediment remains inefficiently identified and the estimation of the stock of deposit is frequently inaccurate. In part, this is due to technical issues connected to difficulties in collecting accurate field measurements without disrupting existing morphologies. In this paper, results from an extensive field campaign are presented; during the campaign a new survey methodology based on acoustic techniques has been tested. Furthermore, a new algorithm for the detection of the soil-water interface, and therefore for the correct esteem of sediment stocks is proposed. Finally, results in regard to bed topography, and morphological features at two different field sites are presented and reveal that a large variability in bed forms is present along sewer networks. Copyright © 2017 Elsevier Ltd. All rights reserved.

High blood pressure, Alzheimer disease and antihypertensive treatment.

PubMed

Marfany, Agustí; Sierra, Cristina; Camafort, Miguel; Doménech, Mónica; Coca, Antonio

2018-03-01

Alzheimer's disease (AD), the most common form of dementia, is a complex disease, the mechanisms of which are poorly understood. AD represents 70% of all dementia cases, affecting up to 50% of elderly persons aged 85 or older, with functional dependence, poor quality of life, institutionalization and mortality. Advanced age is the main risk factor of AD, that is why population ageing, due to life expectancy improvements, increases AD incidence and prevalence, as well as the economic, social, and emotional costs associated with this illness. Existing anti-AD drugs present some limitations, as they target specific downstream neurochemical abnormalities while the upstream underlying pathology continues unchecked. Chronic hypertension has been suggested as one of the largest modifiable risk factors for developing AD. At least 25% of all adults and more than 50% of those over 60 years of age have hypertension. Epidemiological studies have shown that hypertension is a risk factor for dementia and AD, but the association is complex. Some studies have demonstrated that antihypertensive drugs can reduce the risk of AD. This review focuses on current knowledge about the relationship between chronic hypertension and AD as well as antihypertensive treatment effect on AD pathogenesis and its clinical outcomes.

Cell-fusion method to visualize interphase nuclear pore formation.

PubMed

Maeshima, Kazuhiro; Funakoshi, Tomoko; Imamoto, Naoko

2014-01-01

In eukaryotic cells, the nucleus is a complex and sophisticated organelle that organizes genomic DNA to support essential cellular functions. The nuclear surface contains many nuclear pore complexes (NPCs), channels for macromolecular transport between the cytoplasm and nucleus. It is well known that the number of NPCs almost doubles during interphase in cycling cells. However, the mechanism of NPC formation is poorly understood, presumably because a practical system for analysis does not exist. The most difficult obstacle in the visualization of interphase NPC formation is that NPCs already exist after nuclear envelope formation, and these existing NPCs interfere with the observation of nascent NPCs. To overcome this obstacle, we developed a novel system using the cell-fusion technique (heterokaryon method), previously also used to analyze the shuttling of macromolecules between the cytoplasm and the nucleus, to visualize the newly synthesized interphase NPCs. In addition, we used a photobleaching approach that validated the cell-fusion method. We recently used these methods to demonstrate the role of cyclin-dependent protein kinases and of Pom121 in interphase NPC formation in cycling human cells. Here, we describe the details of the cell-fusion approach and compare the system with other NPC formation visualization methods. Copyright © 2014 Elsevier Inc. All rights reserved.

The evolution of phenotypic correlations and ‘developmental memory’

PubMed Central

Watson, Richard A.; Wagner, Günter P.; Pavlicev, Mihaela; Weinreich, Daniel M.; Mills, Rob

2014-01-01

Development introduces structured correlations among traits that may constrain or bias the distribution of phenotypes produced. Moreover, when suitable heritable variation exists, natural selection may alter such constraints and correlations, affecting the phenotypic variation available to subsequent selection. However, exactly how the distribution of phenotypes produced by complex developmental systems can be shaped by past selective environments is poorly understood. Here we investigate the evolution of a network of recurrent non-linear ontogenetic interactions, such as a gene regulation network, in various selective scenarios. We find that evolved networks of this type can exhibit several phenomena that are familiar in cognitive learning systems. These include formation of a distributed associative memory that can ‘store’ and ‘recall’ multiple phenotypes that have been selected in the past, recreate complete adult phenotypic patterns accurately from partial or corrupted embryonic phenotypes, and ‘generalise’ (by exploiting evolved developmental modules) to produce new combinations of phenotypic features. We show that these surprising behaviours follow from an equivalence between the action of natural selection on phenotypic correlations and associative learning, well-understood in the context of neural networks. This helps to explain how development facilitates the evolution of high-fitness phenotypes and how this ability changes over evolutionary time. PMID:24351058

Biannual birth pulses allow filoviruses to persist in bat populations

PubMed Central

Hayman, David T. S.

2015-01-01

Filoviruses Ebolavirus (EBOV) and Marburgvirus (MARV) cause haemorrhagic fevers with high mortality rates, posing significant threats to public health. To understand transmission into human populations, filovirus dynamics within reservoir host populations must be understood. Studies have directly linked filoviruses to bats, but the mechanisms allowing viral persistence within bat populations are poorly understood. Theory suggests seasonal birthing may decrease the probability of pathogen persistence within populations, but data suggest MARV may persist within colonies of seasonally breeding Egyptian fruit bats, Rousettus aegyptiacus. I synthesize available filovirus and bat data in a stochastic compartmental model to explore fundamental questions relating to filovirus ecology: can filoviruses persist within isolated bat colonies; do critical community sizes exist; and how do host–pathogen relationships affect spillover transmission potential? Synchronous annual breeding and shorter incubation periods did not allow filovirus persistence, whereas bi-annual breeding and longer incubation periods, such as reported for Egyptian fruit bats and EBOV in experimental studies, allowed persistence in colony sizes often found in nature. Serological data support the findings, with bats from species with two annual birth pulses more likely to be seropositive (odds ratio (OR) 4.4, 95% confidence interval (CI) 2.5–8.7) than those with one, suggesting that biannual birthing is necessary for filovirus persistence. PMID:25673678

An exploratory study of the experience of fibromyalgia diagnosis in South Africa.

PubMed

Cooper, Silvie; Gilbert, Leah

2017-05-01

Within the conceptual framework of 'medically-ill-defined' conditions, this article focuses on the experiences of 'diagnosis' through a narrative analysis of fibromyalgia (a chronic musculoskeletal pain disorder) in South Africa. In-depth interviews were used to collect narratives from 15 participants. The findings show how the contested and confusing experience of fibromyalgia diagnosis can be understood, by viewing the interactions that patients have with their practitioners, families, peers and colleagues. The currency of fibromyalgia as a diagnosis and the inequalities present in the South African health care system characterise the experiences of symptom recognition, diagnosis and treatment. The analysis reveals how those living with fibromyalgia search for diagnosis, and struggle to maintain legitimacy for their experience in the complex constellation of porous symptoms that appear infrequently. The findings of this study confirm the existing evidence that shows fibromyalgia to be a challenging illness experience, which is attributed to the lack of clarity and legitimacy, and high contestation that surrounds the condition. Additionally, this study presents the ways that limited access to diagnosis and treatment for fibromyalgia in the South African context shapes this specific illness experience, and the value of using narrative approaches to gain insight into how people live with hidden and poorly understood conditions in this environment.

What does productivity really mean? Towards an integrative paradigm in the search for biodiversity-productivity relationships

Treesearch

Liangjun Hu; Qinfeng Guo

2013-01-01

How species diversity relates to productivity remains a major debate. To date, however, the underlying mechanisms that regulate the ecological processes involved are still poorly understood. Three major issues persist in early efforts at resolution. First, in the context that productivity drives species diversity, how the pathways operate is poorly-explained. Second,...

Low serum omega-3 and omega-6 polyunsaturated fatty acids and other metabolites are associated with poor linear growth in young children from rural Malawi

USDA-ARS?s Scientific Manuscript database

Stunting affects ~25% of children <5 y of age and is associated with impaired cognitive and motor development and increased morbidity and mortality. The pathogenesis of stunting is poorly understood. The purpose of this study was to identify altered metabolic pathways associated with child stunting...

Digestive tract absorption of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in a nursing infant

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

McLachlan, M.S.

The digestive tract absorption of environmental contaminants is an important but poorly understood parameter in contaminant is an important but poorly understood parameter in contaminant risk assessments. The net absorption of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in a nursing infant was measured under natural conditions over 12 days. The levels of the substances in the mother's milk were typical for Germany. It was found that for almost all congeners over 90% of the ingested compound was absorbed. This indicates that the common assumption of 100% absorption in nursing infants is reasonable. No firm conclusions could be drawn regarding the absorptionmore » of Cl7- and Cl8DD/F due to high blank levels in the cotton diapers used.« less

Poorly Understood Aspects of Striated Muscle Contraction

PubMed Central

Månsson, Alf

2015-01-01

Muscle contraction results from cyclic interactions between the contractile proteins myosin and actin, driven by the turnover of adenosine triphosphate (ATP). Despite intense studies, several molecular events in the contraction process are poorly understood, including the relationship between force-generation and phosphate-release in the ATP-turnover. Different aspects of the force-generating transition are reflected in the changes in tension development by muscle cells, myofibrils and single molecules upon changes in temperature, altered phosphate concentration, or length perturbations. It has been notoriously difficult to explain all these events within a given theoretical framework and to unequivocally correlate observed events with the atomic structures of the myosin motor. Other incompletely understood issues include the role of the two heads of myosin II and structural changes in the actin filaments as well as the importance of the three-dimensional order. We here review these issues in relation to controversies regarding basic physiological properties of striated muscle. We also briefly consider actomyosin mutation effects in cardiac and skeletal muscle function and the possibility to treat these defects by drugs. PMID:25961006

Poorly understood aspects of striated muscle contraction.

PubMed

Månsson, Alf; Rassier, Dilson; Tsiavaliaris, Georgios

2015-01-01

Muscle contraction results from cyclic interactions between the contractile proteins myosin and actin, driven by the turnover of adenosine triphosphate (ATP). Despite intense studies, several molecular events in the contraction process are poorly understood, including the relationship between force-generation and phosphate-release in the ATP-turnover. Different aspects of the force-generating transition are reflected in the changes in tension development by muscle cells, myofibrils and single molecules upon changes in temperature, altered phosphate concentration, or length perturbations. It has been notoriously difficult to explain all these events within a given theoretical framework and to unequivocally correlate observed events with the atomic structures of the myosin motor. Other incompletely understood issues include the role of the two heads of myosin II and structural changes in the actin filaments as well as the importance of the three-dimensional order. We here review these issues in relation to controversies regarding basic physiological properties of striated muscle. We also briefly consider actomyosin mutation effects in cardiac and skeletal muscle function and the possibility to treat these defects by drugs.

Linking Early Environmental Exposures to Adult Diseases

MedlinePlus

... diseases. Given that many disorders arise during fetal development from disruptions in the dynamic but still poorly understood interplay of genes, environment and nutrition, prevention may have to occur decades ...

Distinct Contributions of T1R2 and T1R3 Taste Receptor Subunits to the Detection of Sweet Stimuli

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

Nie,Y.; Vigues, S.; Hobbs, J.

2005-01-01

The molecular mechanisms by which G protein-coupled receptor (GPCR)-type chemosensory receptors of animals selectively interact with their cognate ligands remain poorly understood. There is growing evidence that many chemosensory receptors exist in multimeric complexes, though little is known about the relative contributions of individual subunits to receptor functions. This study showed that each of the two subunits in the mammalian heteromeric T1R2:T1R3 sweet taste receptor binds sweet stimuli, though with distinct affinities and conformational changes. Furthermore, ligand affinities for T1R3 are drastically reduced by the introduction of a single amino acid change associated with decreased sweet taste sensitivity in mice.more » Thus, individual T1R subunits increase the receptive range of the sweet taste receptor, offering a functional mechanism for phenotypic variations in sweet taste.« less

Processes Contributing to the Maintenance of Flying Phobia: A Narrative Review

PubMed Central

Clark, Gavin I.; Rock, Adam J.

2016-01-01

Flying phobia is a highly prevalent anxiety disorder, which causes sufferers significant distress and life interference. The processes which maintain flying phobia remain poorly understood. A systematic search of the literature was performed to identify what research has been conducted into the processes which may be involved in the fear of flying and whether processes which are believed to maintain other anxiety disorder diagnoses have been investigated in flying phobia. The results of the literature review are presented and related to existing cognitive behavioral theory and research. The results indicate that little research has been conducted into a number of areas considered important in the wider cognitive behavioral literature on anxiety disorders: namely attention, mental imagery, memory, worry, and safety-seeking behaviors. The review proposes a hypothetical model, derived from cognitive behavioral theory, for the processes which may be involved in maintaining flying phobia, and considers a number of areas for future research. PMID:27313550

Population Pulsation Resonances of Excitons in Monolayer MoSe 2 with Sub-1 μeV Linewidths

DOE PAGES

Schaibley, John R.; Karin, Todd; Yu, Hongyi; ...

2015-04-01

Monolayer transition metal dichalcogenides, a new class of atomically thin semiconductors, possess optically coupled 2D valley excitons. The nature of exciton relaxation in these systems is currently poorly understood. In this paper, we investigate exciton relaxation in monolayer MoSe 2 using polarization-resolved coherent nonlinear optical spectroscopy with high spectral resolution. We report strikingly narrow population pulsation resonances with two different characteristic linewidths of 1 and <0.2 μeV at low temperature. These linewidths are more than 3 orders of magnitude narrower than the photoluminescence and absorption linewidth, and indicate that a component of the exciton relaxation dynamics occurs on time scalesmore » longer than 1 ns. Finally, the ultranarrow resonance (<0.2 μeV) emerges with increasing excitation intensity, and implies the existence of a long-lived state whose lifetime exceeds 6 ns.« less

Rational noncompliance with prescribed medical treatment.

PubMed

Stewart, Douglas O; DeMarco, Joseph P

2010-09-01

Despite the attention that patient noncompliance has received from medical researchers, patient noncompliance remains poorly understood and difficult to alter. With a better theory of patient noncompliance, both greater success in achieving compliance and greater respect for patient decision making are likely. The theory presented, which uses a microeconomic approach, bridges a gap in the extant literature that has so far ignored the contributions of this classic perspective on decision making involving the tradeoff of costs and benefits. The model also generates a surprising conclusion: that patients are typically acting rationally when they refuse to comply with certain treatments. However, compliance is predicted to rise with increased benefits and reduced costs. The prediction that noncompliance is rational is especially true in chronic conditions at the point that treatment begins to move closer to the medically ideal treatment level. Although the details of this theory have not been tested empirically, it is well supported by existing prospective and retrospective studies.

Homelessness and Housing Insecurity Among Former Prisoners

PubMed Central

HERBERT, CLAIRE W.; MORENOFF, JEFFREY D.; HARDING, DAVID J.

2016-01-01

The United States has experienced dramatic increases in both incarceration rates and the population of insecurely housed or homeless persons since the 1980s. These marginalized populations have strong overlaps, with many people being poor, minority, and from an urban area. That a relationship between homelessness, housing insecurity, and incarceration exists is clear, but the extent and nature of this relationship is not yet adequately understood. We use longitudinal, administrative data on Michigan parolees released in 2003 to examine returning prisoners’ experiences with housing insecurity and homelessness. Our analysis finds relatively low rates of outright homelessness among former prisoners, but very high rates of housing insecurity, much of which is linked to features of community supervision, such as intermediate sanctions, returns to prison, and absconding. We identify risk factors for housing insecurity, including mental illness, substance use, prior incarceration, and homelessness, as well as protective “buffers” against insecurity and homelessness, including earnings and social supports. PMID:26913294

Effect of hydrogen on the integrity of aluminium–oxide interface at elevated temperatures

PubMed Central

Li, Meng; Xie, De-Gang; Ma, Evan; Li, Ju; Zhang, Xi-Xiang; Shan, Zhi-Wei

2017-01-01

Hydrogen can facilitate the detachment of protective oxide layer off metals and alloys. The degradation is usually exacerbated at elevated temperatures in many industrial applications; however, its origin remains poorly understood. Here by heating hydrogenated aluminium inside an environmental transmission electron microscope, we show that hydrogen exposure of just a few minutes can greatly degrade the high temperature integrity of metal–oxide interface. Moreover, there exists a critical temperature of ∼150 °C, above which the growth of cavities at the metal–oxide interface reverses to shrinkage, followed by the formation of a few giant cavities. Vacancy supersaturation, activation of a long-range diffusion pathway along the detached interface and the dissociation of hydrogen-vacancy complexes are critical factors affecting this behaviour. These results enrich the understanding of hydrogen-induced interfacial failure at elevated temperatures. PMID:28218260

Breakup of a homeobox cluster after genome duplication in teleosts

PubMed Central

Mulley, John F.; Chiu, Chi-hua; Holland, Peter W. H.

2006-01-01

Several families of homeobox genes are arranged in genomic clusters in metazoan genomes, including the Hox, ParaHox, NK, Rhox, and Iroquois gene clusters. The selective pressures responsible for maintenance of these gene clusters are poorly understood. The ParaHox gene cluster is evolutionarily conserved between amphioxus and human but is fragmented in teleost fishes. We show that two basal ray-finned fish, Polypterus and Amia, each possess an intact ParaHox cluster; this implies that the selective pressure maintaining clustering was lost after whole-genome duplication in teleosts. Cluster breakup is because of gene loss, not transposition or inversion, and the total number of ParaHox genes is the same in teleosts, human, mouse, and frog. We propose that this homeobox gene cluster is held together in chordates by the existence of interdigitated control regions that could be separated after locus duplication in the teleost fish. PMID:16801555

Influence of metal concentrations, percent salinity, and length of exposure on the metabolic rate of fathead minnows (Pimephales promelas).

PubMed

Pistole, David H; Peles, John D; Taylor, Kelly

2008-07-01

Understanding the effects of chemical toxicants on energetic processes is an important aspect of ecotoxicology. However, the influence of toxicant concentration and time of exposure on metabolism in aquatic organisms is still poorly understood. The purpose of this investigation was to determine the influence of increasing levels of three stressors (Cu, Cd, percent salinity) and exposure time (24 h and 96 h) on the metabolic rate of fathead minnows (Pimephales promelas). In all 24-h exposures, there existed a threshold concentration, above which metabolic rate decreased significantly compared to the control and lower concentrations. In contrast, the metabolic rate of fish exposed for 96 h increased significantly in all concentrations compared to fish from the control. We suggest fathead minnows exhibit a consistent pattern of metabolic response to stressors, regardless of the physiological mechanisms involved, and that this response differs as a function of time of exposure.

The Migraine-Ischemic Stroke Relation in Young Adults

PubMed Central

Pezzini, Alessandro; Del Zotto, Elisabetta; Giossi, Alessia; Volonghi, Irene; Costa, Paolo; Dalla Volta, Giorgio; Padovani, Alessandro

2011-01-01

In spite of the strong epidemiologic evidence linking migraine and ischemic stroke in young adults, the mechanisms explaining this association remain poorly understood. The observation that stroke occurs more frequently during the interictal phase of migraine prompts to speculation that an indirect relation between the two diseases might exist. In this regard, four major issues might be considered which may be summarized as follows: (1) the migraine-ischemic stroke relation is influenced by specific risk factors such as patent foramen ovale or endothelial dysfunction and more frequent in particular conditions like spontaneous cervical artery dissection; (2) migraine is associated with an increased prevalence of cardiovascular risk factors; (3) the link is caused by migraine-specific drugs; (4) migraine and ischemic vascular events are linked via a genetic component. In the present paper, we will review epidemiological studies, discuss potential mechanisms of migraine-induced stroke and comorbid ischemic stroke, and pose new research questions. PMID:21197470

A quiet flow Ludwieg tube for study of transition in compressible boundary layers: Design and feasibility

NASA Technical Reports Server (NTRS)

Schneider, Steven P.

1991-01-01

Laminar-turbulent transition in high speed boundary layers is a complicated problem which is still poorly understood, partly because of experimental ambiguities caused by operating in noisy wind tunnels. The NASA Langley experience with quiet tunnel design has been used to design a quiet flow tunnel which can be constructed less expensively. Fabrication techniques have been investigated, and inviscid, boundary layer, and stability computer codes have been adapted for use in the nozzle design. Construction of such a facility seems feasible, at a reasonable cost. Two facilities have been proposed: a large one, with a quiet flow region large enough to study the end of transition, and a smaller and less expensive one, capable of studying low Reynolds number issues such as receptivity. Funding for either facility remains to be obtained, although key facility elements have been obtained and are being integrated into the existing Purdue supersonic facilities.

Changes in the Mechanisms Causing Rapid Drought Cessation in the Southeastern United States

NASA Astrophysics Data System (ADS)

Maxwell, Justin T.; Knapp, Paul A.; Ortegren, Jason T.; Ficklin, Darren L.; Soulé, Peter T.

2017-12-01

The synoptic processes that end droughts are poorly understood, yet have significant climatological implications. Here we examined the spatiotemporal patterns of rapid drought cessation (RDC) in the southeastern United States during the1979-2013 warm season (April-November) for three storm types: Frontal, Tropical, and Air mass. We defined RDC as a 1 month shift in soil moisture sufficient to alleviate an existing drought. We found that 73% of all warm-season droughts were ended by RDC events and the three storm-type groups ended droughts over similar spatial areas. Frontal storms were the most frequent mechanism for RDC events, yet their occurrences significantly decreased and were negatively related to increases in Northern Hemisphere air temperatures. Projected future warming in the Northern Hemisphere suggests a continued decline in the frequency and relative contribution of Frontal storms as RDC events, potentially influencing the timing and spatial scale of drought cessation in the southeastern U.S.

Initial genome sequencing and analysis of multiple myeloma

PubMed Central

Chapman, Michael A.; Lawrence, Michael S.; Keats, Jonathan J.; Cibulskis, Kristian; Sougnez, Carrie; Schinzel, Anna C.; Harview, Christina L.; Brunet, Jean-Philippe; Ahmann, Gregory J.; Adli, Mazhar; Anderson, Kenneth C.; Ardlie, Kristin G.; Auclair, Daniel; Baker, Angela; Bergsagel, P. Leif; Bernstein, Bradley E.; Drier, Yotam; Fonseca, Rafael; Gabriel, Stacey B.; Hofmeister, Craig C.; Jagannath, Sundar; Jakubowiak, Andrzej J.; Krishnan, Amrita; Levy, Joan; Liefeld, Ted; Lonial, Sagar; Mahan, Scott; Mfuko, Bunmi; Monti, Stefano; Perkins, Louise M.; Onofrio, Robb; Pugh, Trevor J.; Vincent Rajkumar, S.; Ramos, Alex H.; Siegel, David S.; Sivachenko, Andrey; Trudel, Suzanne; Vij, Ravi; Voet, Douglas; Winckler, Wendy; Zimmerman, Todd; Carpten, John; Trent, Jeff; Hahn, William C.; Garraway, Levi A.; Meyerson, Matthew; Lander, Eric S.; Getz, Gad; Golub, Todd R.

2013-01-01

Multiple myeloma is an incurable malignancy of plasma cells, and its pathogenesis is poorly understood. Here we report the massively parallel sequencing of 38 tumor genomes and their comparison to matched normal DNAs. Several new and unexpected oncogenic mechanisms were suggested by the pattern of somatic mutation across the dataset. These include the mutation of genes involved in protein translation (seen in nearly half of the patients), genes involved in histone methylation, and genes involved in blood coagulation. In addition, a broader than anticipated role of NF-κB signaling was suggested by mutations in 11 members of the NF-κB pathway. Of potential immediate clinical relevance, activating mutations of the kinase BRAF were observed in 4% of patients, suggesting the evaluation of BRAF inhibitors in multiple myeloma clinical trials. These results indicate that cancer genome sequencing of large collections of samples will yield new insights into cancer not anticipated by existing knowledge. PMID:21430775

Aeromagnetic anomaly patterns reveal buried faults along the eastern margin of the Wilkes Subglacial Basin (East Antarctica)

USGS Publications Warehouse

Armadillo, E.; Ferraccioli, F.; Zunino, A.; Bozzo, E.

2007-01-01

The Wilkes Subglacial Basin (WSB) is the major morphological feature recognized in the hinterland of the Transantarctic Mountains. The origin of this basin remains contentious and relatively poorly understood due to the lack of extensive geophysical exploration. We present a new aeromagnetic anomaly map over the transition between the Transantarctic Mountains and the WSB for an area adjacent to northern Victoria Land. The aeromagnetic map reveals the existence of subglacial faults along the eastern margin of the WSB. These inferred faults connect previously proposed fault zones over Oates Land with those mapped along the Ross Sea Coast. Specifically, we suggest a link between the Matusevich Frature Zone and the Priestley Fault during the Cenozoic. The new evidence for structural control on the eastern margin of the WSB implies that a purely flexural origin for the basin is unlikely.

Epidemic cholera spreads like wildfire

NASA Astrophysics Data System (ADS)

Roy, Manojit; Zinck, Richard D.; Bouma, Menno J.; Pascual, Mercedes

2014-01-01

Cholera is on the rise globally, especially epidemic cholera which is characterized by intermittent and unpredictable outbreaks that punctuate periods of regional disease fade-out. These epidemic dynamics remain however poorly understood. Here we examine records for epidemic cholera over both contemporary and historical timelines, from Africa (1990-2006) and former British India (1882-1939). We find that the frequency distribution of outbreak size is fat-tailed, scaling approximately as a power-law. This pattern which shows strong parallels with wildfires is incompatible with existing cholera models developed for endemic regions, as it implies a fundamental role for stochastic transmission and local depletion of susceptible hosts. Application of a recently developed forest-fire model indicates that epidemic cholera dynamics are located above a critical phase transition and propagate in similar ways to aggressive wildfires. These findings have implications for the effectiveness of control measures and the mechanisms that ultimately limit the size of outbreaks.

Immature Stages of Development in the Parasitoid Wasp, Diachasmimorpha longicaudata

PubMed Central

Paladino, Leonela Zusel Carabajal; Papeschi, Alba Graciela; Cladera, Jorge Luis

2010-01-01

The morphological changes experienced during the immature stages of the solitary parasitoid Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae: Opiinae) were studied. This natural enemy of several species of tephritid fruit flies is widely used in biological control strategies. Immature stages are poorly understood in endoparasitoids because they exist within the host. In the present work, developmental processes are described for this species, reared in Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) larvae under controlled environmental conditions. At 25° C, 85% RH, and with an 18:6 L:D photoperiod, preimaginal development takes about 16 days. Five preimaginal stages can be described: egg, three larval instars, prepupa, pupa, and pharate adult. Superparasitism was found in 20% of the host pupae, and the number of oviposition scars was positively correlated with the number of parasitoid larvae per host puparium. The results are compared and discussed with previous studies on related species. PMID:20569133

Deep groundwater and potential subsurface habitats beneath an Antarctic dry valley

PubMed Central

Mikucki, J. A.; Auken, E.; Tulaczyk, S.; Virginia, R. A.; Schamper, C.; Sørensen, K. I.; Doran, P. T.; Dugan, H.; Foley, N.

2015-01-01

The occurrence of groundwater in Antarctica, particularly in the ice-free regions and along the coastal margins is poorly understood. Here we use an airborne transient electromagnetic (AEM) sensor to produce extensive imagery of resistivity beneath Taylor Valley. Regional-scale zones of low subsurface resistivity were detected that are inconsistent with the high resistivity of glacier ice or dry permafrost in this region. We interpret these results as an indication that liquid, with sufficiently high solute content, exists at temperatures well below freezing and considered within the range suitable for microbial life. These inferred brines are widespread within permafrost and extend below glaciers and lakes. One system emanates from below Taylor Glacier into Lake Bonney and a second system connects the ocean with the eastern 18 km of the valley. A connection between these two basins was not detected to the depth limitation of the AEM survey (∼350 m). PMID:25919365

Dominant phonon polarization conversion across dimensionally mismatched interfaces: Carbon-nanotube-graphene junction

NASA Astrophysics Data System (ADS)

Shi, Jingjing; Lee, Jonghoon; Dong, Yalin; Roy, Ajit; Fisher, Timothy S.; Ruan, Xiulin

2018-04-01

Dimensionally mismatched interfaces are emerging for thermal management applications, but thermal transport physics remains poorly understood. Here we consider the carbon-nanotube-graphene junction, which is a dimensionally mismatched interface between one- and two-dimensional materials and is the building block for carbon-nanotube (CNT)-graphene three-dimensional networks. We predict the transmission function of individual phonon modes using the wave packet method; surprisingly, most incident phonon modes show predominantly polarization conversion behavior. For instance, longitudinal acoustic (LA) polarizations incident from CNTs transmit mainly into flexural transverse (ZA) polarizations in graphene. The frequency stays the same as the incident mode, indicating elastic transmission. Polarization conversion is more significant as the phonon wavelength increases. We attribute such unique phonon polarization conversion behavior to the dimensional mismatch across the interface, and it opens significantly new phonon transport channels as compared to existing theories where polarization conversion is neglected.

The Neuroscience of Consumer Choice

PubMed Central

Hsu, Ming; Yoon, Carolyn

2015-01-01

We review progress and challenges relating to scientific and applied goals of the nascent field of consumer neuroscience. Scientifically, substantial progress has been made in understanding the neurobiology of choice processes. Further advances, however, require researchers to begin clarifying the set of developmental and cognitive processes that shape and constrain choices. First, despite the centrality of preferences in theories of consumer choice, we still know little about where preferences come from and the underlying developmental processes. Second, the role of attention and memory processes in consumer choice remains poorly understood, despite importance ascribed to them in interpreting data from the field. The applied goal of consumer neuroscience concerns our ability to translate this understanding to augment prediction at the population level. Although the use of neuroscientific data for market-level predictions remains speculative, there is growing evidence of superiority in specific cases over existing market research techniques. PMID:26665152

Causes of learning disability and epilepsy: a review.

PubMed

Prince, Elizabeth; Ring, Howard

2011-04-01

Although the association between learning disability and epilepsy is well known, until relatively recently specific processes underlying this association were relatively poorly understood. However, scientific advances in molecular biology are starting to guide researchers towards descriptions of genetic and pathophysiological processes that may explain why syndromes of epilepsy and learning disability often co-exist. This article will focus largely on three areas of advancing knowledge: insights gained from wider use of genome-wide array comparative genomic hybridization (aCGH), specific insights gained from detailed study of Rett syndrome and the role of abnormalities of astrocytic function in predisposing to both epilepsy and learning disability. The enormous complexity of the biological underpinnings of the co-occurrence of epilepsy and learning disability are becoming apparent. In the future it is likely that research into therapeutic approaches will include, amongst other approaches, investigations of gene structure and expression, the role of astrocytes and the stability of dendritic spines.

Epidemic cholera spreads like wildfire

PubMed Central

Roy, Manojit; Zinck, Richard D.; Bouma, Menno J.; Pascual, Mercedes

2014-01-01

Cholera is on the rise globally, especially epidemic cholera which is characterized by intermittent and unpredictable outbreaks that punctuate periods of regional disease fade-out. These epidemic dynamics remain however poorly understood. Here we examine records for epidemic cholera over both contemporary and historical timelines, from Africa (1990–2006) and former British India (1882–1939). We find that the frequency distribution of outbreak size is fat-tailed, scaling approximately as a power-law. This pattern which shows strong parallels with wildfires is incompatible with existing cholera models developed for endemic regions, as it implies a fundamental role for stochastic transmission and local depletion of susceptible hosts. Application of a recently developed forest-fire model indicates that epidemic cholera dynamics are located above a critical phase transition and propagate in similar ways to aggressive wildfires. These findings have implications for the effectiveness of control measures and the mechanisms that ultimately limit the size of outbreaks. PMID:24424273

Epidemic cholera spreads like wildfire.

PubMed

Roy, Manojit; Zinck, Richard D; Bouma, Menno J; Pascual, Mercedes

2014-01-15

Cholera is on the rise globally, especially epidemic cholera which is characterized by intermittent and unpredictable outbreaks that punctuate periods of regional disease fade-out. These epidemic dynamics remain however poorly understood. Here we examine records for epidemic cholera over both contemporary and historical timelines, from Africa (1990-2006) and former British India (1882-1939). We find that the frequency distribution of outbreak size is fat-tailed, scaling approximately as a power-law. This pattern which shows strong parallels with wildfires is incompatible with existing cholera models developed for endemic regions, as it implies a fundamental role for stochastic transmission and local depletion of susceptible hosts. Application of a recently developed forest-fire model indicates that epidemic cholera dynamics are located above a critical phase transition and propagate in similar ways to aggressive wildfires. These findings have implications for the effectiveness of control measures and the mechanisms that ultimately limit the size of outbreaks.

Eighteenth century Yersinia pestis genomes reveal the long-term persistence of an historical plague focus.

PubMed

Bos, Kirsten I; Herbig, Alexander; Sahl, Jason; Waglechner, Nicholas; Fourment, Mathieu; Forrest, Stephen A; Klunk, Jennifer; Schuenemann, Verena J; Poinar, Debi; Kuch, Melanie; Golding, G Brian; Dutour, Olivier; Keim, Paul; Wagner, David M; Holmes, Edward C; Krause, Johannes; Poinar, Hendrik N

2016-01-21

The 14th-18th century pandemic of Yersinia pestis caused devastating disease outbreaks in Europe for almost 400 years. The reasons for plague's persistence and abrupt disappearance in Europe are poorly understood, but could have been due to either the presence of now-extinct plague foci in Europe itself, or successive disease introductions from other locations. Here we present five Y. pestis genomes from one of the last European outbreaks of plague, from 1722 in Marseille, France. The lineage identified has not been found in any extant Y. pestis foci sampled to date, and has its ancestry in strains obtained from victims of the 14th century Black Death. These data suggest the existence of a previously uncharacterized historical plague focus that persisted for at least three centuries. We propose that this disease source may have been responsible for the many resurgences of plague in Europe following the Black Death.

Local Generation and Propagation of Ripples along the Septotemporal Axis of the Hippocampus

PubMed Central

Patel, Jagdish; Schomburg, Erik W.; Berényi, Antal; Fujisawa, Shigeyoshi

2013-01-01

A topographical relationship exists between the septotemporal segments of the hippocampus and their entorhinal–neocortical targets, but the physiological organization of activity along the septotemporal axis is poorly understood. We recorded sharp-wave ripple patterns in rats during sleep from the entire septotemporal axis of the CA1 pyramidal layer. Qualitatively similar ripples emerged at all levels. From the local seed, ripples traveled septally or temporally at a speed of ∼0.35 m/s, and the spatial spread depended on ripple magnitude. Ripples propagated smoothly across the septal and intermediate segments of the hippocampus, but ripples in the temporal segment often remained isolated. These findings show that ripples can combine information from the septal and intermediate hippocampus and transfer integrated signals downstream. In contrast, ripples that emerged in the temporal pole broadcast largely independent information to their cortical and subcortical targets. PMID:24155307

Clearing the haze: the complexities and challenges of research on state marijuana laws.

PubMed

Choo, Esther K; Emery, Sherry L

2017-04-01

As states increasingly liberalize marijuana laws, high-quality research is needed that will inform the public and policymakers about the health and societal impact of these laws. However, there are many challenges to studying marijuana policy, including the heterogeneity of the drug and its use, the variability in the laws and their implementation from state to state, the need to capture a wide variety of relevant outcomes, and the poorly understood influence of marijuana commercialization. Furthermore, current instruments generally fail to distinguish between types of users and lack accurate and detailed measures of use. This review provides a background on marijuana laws in the United States and an overview of existing policy research, discusses methodological considerations when planning analysis of state marijuana laws, and highlights specific topics needing further development and investigation. © 2016 New York Academy of Sciences.

Patterns of neuroAIDS in Africa.

PubMed

Tadesse, Tizeta; Langford, Dianne; Manji, Karim; Mehari, Enawgaw

2005-01-01

According to UNAIDS, the African population accounts for greater than half of persons infected with HIV. Nevertheless, little information exists characterizing HIV in this population. Thus, the natural history and progression of HIV in the African population is virtually undocumented and therefore, poorly understood. Information regarding virtually every aspect of the disease including microbiology, pathogenicity, virulence, and clinical manifestation is based largely on data from select and limited populations. During the HAART-era, we have seen dramatic and significant changes in patterns of NeuroAIDS in patients in clinical cohorts from the United States and Western Europe. These observations have led to increased understanding of the progression of NeuroAIDS and have improved our ability to design treatment regimens to combat CNS complications resulting from HIV. Despite the existence of antiretroviral therapy for HIV, its absence in Africa along with poor treatments for opportunistic infections associated with HIV have become the main sources of neurological morbidity and mortality. In this context, we are presented with a unique opportunity to cultivate and enhance our understanding of the natural history and progression of NeuroAIDS in the African population thereby, better equipping healthcare providers, patients and their families in addressing this epidemic. This concept is particularly important as rapidly improving and more accessible anti-HIV medications and medications for the treatment of opportunistic infections become available to third world countries such as Africa. We believe that it is imperative to foster research, education and training between institutions in the industrialized world and Africa to close the gap in understanding patterns of NeuroAIDS in Africa.

An inexpensive and portable drill rig for bedrock groundwater studies in headwater catchments

Treesearch

C. Gabrielli; J.J. McDonnell

2011-01-01

Bedrock groundwater dynamics in headwater catchments are poorly understood and poorly characterized. Here, we present an inexpensive and portable bedrock drilling system designed for use in remote locations. Our system is capable of drilling bedrock wells up to 11 m deep and 38 mm in diameter in a wide range of bedrock types. The drill consists of a lawn mower engine...

Researchers Realize Major Breakthrough in Understanding Endometriosis

MedlinePlus

... a rarely studied and poorly understood disease that affects many, many women.” Health Terms: Women's Health RELATED LINKS RSS LISTSERV YOUTUBE FACEBOOK TWITTER GOOGLE+ NIH...T URNING D ISCOVERY I ...

Stem cell-based growth, regeneration, and remodeling of the planarian intestine

PubMed Central

Forsthoefel, David J.; Park, Amanda E.; Newmark, Phillip A.

2011-01-01

Although some animals are capable of regenerating organs, the mechanisms by which this is achieved are poorly understood. In planarians, pluripotent somatic stem cells called neoblasts supply new cells for growth, replenish tissues in response to cellular turnover, and regenerate tissues after injury. For most tissues and organs, however, the spatiotemporal dynamics of stem cell differentiation and the fate of tissue that existed prior to injury have not been characterized systematically. Utilizing in vivo imaging and bromodeoxyuridine pulse-chase experiments, we have analyzed growth and regeneration of the planarian intestine, the organ responsible for digestion and nutrient distribution. During growth, we observe that new gut branches are added along the entire anteroposterior axis. We find that new enterocytes differentiate throughout the intestine rather than in specific growth zones, suggesting that branching morphogenesis is achieved primarily by remodeling of differentiated intestinal tissues. During regeneration, we also demonstrate a previously unappreciated degree of intestinal remodeling, in which pre-existing posterior gut tissue contributes extensively to the newly formed anterior gut, and vice versa. By contrast to growing animals, differentiation of new intestinal cells occurs at preferential locations, including within newly generated tissue (the blastema), and along pre-existing intestinal branches undergoing remodeling. Our results indicate that growth and regeneration of the planarian intestine are achieved by coordinated differentiation of stem cells and the remodeling of pre-existing tissues. Elucidation of the mechanisms by which these processes are integrated will be critical for understanding organogenesis in a post-embryonic context. PMID:21664348

Effects of landscape gradients on wetland vegetation communities: information for large-scale restoration

USGS Publications Warehouse

Zweig, Christa L.; Kitchens, Wiley M.

2008-01-01

Projects of the scope of the restoration of the Florida Everglades require substantial information regarding ecological mechanisms, and these are often poorly understood. We provide critical base knowledge for Everglades restoration by characterizing the existing vegetation communities of an Everglades remnant, describing how present and historic hydrology affect wetland vegetation community composition, and documenting change from communities described in previous studies. Vegetation biomass samples were collected along transects across Water Conservation Area 3A South (3AS). Ten community types were present between November 2002 and 2005. Separate analyses for key a priori groups (slough, wet prairie, and sawgrass) provided detailed conclusions about effects of historic hydrology on the vegetation of 3AS. Communities were affected by hydrologic variables LIP to four years previous to the sample. We identified wet prairie/slough species such as Eleocharis spp. and Nymphaea odorata as short-term sentinel species of community change. Sawgrass and N. odorata should be monitored for long-term change. Comparisons to preceding studies indicated that many of the communities of previous times, when conditions were drier, no longer exist in our study area and have been replaced by deeper water community types.

The Genomic Basis of Evolutionary Innovation in Pseudomonas aeruginosa

PubMed Central

Wagner, Andreas; MacLean, R. Craig

2016-01-01

Novel traits play a key role in evolution, but their origins remain poorly understood. Here we address this problem by using experimental evolution to study bacterial innovation in real time. We allowed 380 populations of Pseudomonas aeruginosa to adapt to 95 different carbon sources that challenged bacteria with either evolving novel metabolic traits or optimizing existing traits. Whole genome sequencing of more than 80 clones revealed profound differences in the genetic basis of innovation and optimization. Innovation was associated with the rapid acquisition of mutations in genes involved in transcription and metabolism. Mutations in pre-existing duplicate genes in the P. aeruginosa genome were common during innovation, but not optimization. These duplicate genes may have been acquired by P. aeruginosa due to either spontaneous gene amplification or horizontal gene transfer. High throughput phenotype assays revealed that novelty was associated with increased pleiotropic costs that are likely to constrain innovation. However, mutations in duplicate genes with close homologs in the P. aeruginosa genome were associated with low pleiotropic costs compared to mutations in duplicate genes with distant homologs in the P. aeruginosa genome, suggesting that functional redundancy between duplicates facilitates innovation by buffering pleiotropic costs. PMID:27149698

Soil heating during wildfires and prescribed burns: a global evaluation based on existing and new data

NASA Astrophysics Data System (ADS)

Doerr, Stefan; Santin, Cristina; Reardon, James; Mataix-Solera, Jorge; Stoof, Cathelijne; Bryant, Rob; Miesel, Jessica; Badia, David

2017-04-01

Heat transfer from the combustion of ground fuels and soil organic matter during vegetation fires can cause substantial changes to the physical, chemical and biological characteristics of soils. Numerous studies have investigated the effects of wildfires and prescribed burns on soil properties based either on field samples or using laboratory experiments. Critical thresholds for changes in soil properties, however, have been determined largely based on laboratory heating experimentation. These experimental approaches have been criticized for being inadequate for reflecting the actual heating patterns soil experienced in vegetation fires, which remain poorly understood. To address this research gap, this study reviews existing and evaluates new field data on key soil heating parameters determined during wildfires and prescribed burns from a wide range of environments. The results highlight the high spatial and temporal variability in soil heating patters not only between, but also within fires. Most wildfires and prescribed burns are associated with heat pulses that are much shorter than those typically applied in laboratory studies, which can lead to erroneous conclusions when results from laboratory studies are used to predict fire impacts on soils in the field.

Proximate Sources of Population Sex Imbalance in India

PubMed Central

OSTER, EMILY

2009-01-01

There is a population sex imbalance in India. Despite a consensus that this imbalance is due to excess female mortality, the specific source of this excess mortality remains poorly understood. I use microdata on child survival in India to analyze the proximate sources of the sex imbalance. I address two questions: when in life does the sex imbalance arise, and what health or nutritional investments are specifically responsible for its appearance? I present a new methodology that uses microdata on child survival. This methodology explicitly takes into account both the possibility of naturally occurring sex differences in survival and possible differences between investments in their importance for survival. Consistent with existing literature, I find significant excess female mortality in childhood, particularly between the ages of 1 and 5, and argue that the sex imbalance that exists by age 5 is large enough to explain virtually the entire imbalance in the population. Within this age group, sex differences in vaccinations explain between 20% and 30% of excess female mortality, malnutrition explains an additional 20%, and differences in treatment for illness play a smaller role. Together, these investments account for approximately 50% of the sex imbalance in mortality in India. PMID:21305396

Sensory adaptation for timing perception.

PubMed

Roseboom, Warrick; Linares, Daniel; Nishida, Shin'ya

2015-04-22

Recent sensory experience modifies subjective timing perception. For example, when visual events repeatedly lead auditory events, such as when the sound and video tracks of a movie are out of sync, subsequent vision-leads-audio presentations are reported as more simultaneous. This phenomenon could provide insights into the fundamental problem of how timing is represented in the brain, but the underlying mechanisms are poorly understood. Here, we show that the effect of recent experience on timing perception is not just subjective; recent sensory experience also modifies relative timing discrimination. This result indicates that recent sensory history alters the encoding of relative timing in sensory areas, excluding explanations of the subjective phenomenon based only on decision-level changes. The pattern of changes in timing discrimination suggests the existence of two sensory components, similar to those previously reported for visual spatial attributes: a lateral shift in the nonlinear transducer that maps relative timing into perceptual relative timing and an increase in transducer slope around the exposed timing. The existence of these components would suggest that previous explanations of how recent experience may change the sensory encoding of timing, such as changes in sensory latencies or simple implementations of neural population codes, cannot account for the effect of sensory adaptation on timing perception.

Trajectories of Future Land Use for Earth System Modeling of the Northeast United States

NASA Astrophysics Data System (ADS)

Rosenzweig, B.; Vorosmarty, C. J.; Lu, X.; Kicklighter, D. W.

2015-12-01

The U.S. Northeast includes some of the nation's most populated cities and their supporting hinterlands, with an urban corridor spanning from Maine to Virginia. The megaregion's centuries-long history of landscape transformations has had enduring impact on the region's hydrology, ecosystems and socioeconomy. Driven by policy decisions made in the next decade, future landscape changes will also interplay with climate change, with multi-decadal effects that are currently poorly understood. While existing national and global land cover trajectories will play an important role in understanding these future impacts, they do not allow for investigation of many issues of interest to regional stakeholders, such as local zoning and suburban sprawl, the development of a regional food system, or varying rates of natural lands protection. Existing land cover trajectories also do not usually provide the detail needed as input drivers for earth system models, such as disaggregated vegetation types or harmonized time series of infrastructure management. We discuss the development of a simple land use/land cover allocation scheme to develop such needed trajectories, their implementation for 4 regional socioeconomic pathways developed collaboratively with regional stakeholders, and their preliminary use in regional ecosystem modeling.

Redox Signaling Regulated by Cysteine Persulfide and Protein Polysulfidation.

PubMed

Kasamatsu, Shingo; Nishimura, Akira; Morita, Masanobu; Matsunaga, Tetsuro; Abdul Hamid, Hisyam; Akaike, Takaaki

2016-12-15

For decades, reactive persulfide species including cysteine persulfide (CysSSH) have been known to exist endogenously in organisms. However, the physiological significance of endogenous persulfides remains poorly understood. That cystathionine β-synthase and cystathionine γ-lyase produced CysSSH from cystine was recently demonstrated. An endogenous sulfur transfer system involving CysSSH evidently generates glutathione persulfide (GSSH) that exists at concentrations greater than 100 μM in vivo. Because reactive persulfide species such as CysSSH and GSSH have higher nucleophilicity than parental cysteine (Cys) and glutathione do, these reactive species exhibit strong scavenging activities against oxidants, e.g., hydrogen peroxide, and electrophiles, which contributes to redox signaling regulation. Also, several papers indicated that various proteins and enzymes have Cys polysulfides including CysSSH at their specific Cys residues, which is called protein polysulfidation. Apart from the redox signaling regulatory mechanism, another plausible function of protein polysulfidation is providing protection for protein thiol residues against irreversible chemical modification caused by oxidants and electrophiles. Elucidation of the redox signaling regulatory mechanism of reactive persulfide species including small thiol molecules and thiol-containing proteins should lead to the development of new therapeutic strategies and drug discoveries for oxidative and electrophilic stress-related diseases.

76 FR 61379 - Final Recovery Plan, Bexar County Karst Invertebrates

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-04

... 200, Austin, TX (512-490-0057 ext. 223). FOR FURTHER INFORMATION CONTACT: Adam Zerrenner, at the above... poorly understood, recovery is also dependant on incorporating research findings into adaptive management...

Fine-scale landscape genetics of the American badger (Taxidea taxus): disentangling landscape effects and sampling artifacts in a poorly understood species

PubMed Central

Kierepka, E M; Latch, E K

2016-01-01

Landscape genetics is a powerful tool for conservation because it identifies landscape features that are important for maintaining genetic connectivity between populations within heterogeneous landscapes. However, using landscape genetics in poorly understood species presents a number of challenges, namely, limited life history information for the focal population and spatially biased sampling. Both obstacles can reduce power in statistics, particularly in individual-based studies. In this study, we genotyped 233 American badgers in Wisconsin at 12 microsatellite loci to identify alternative statistical approaches that can be applied to poorly understood species in an individual-based framework. Badgers are protected in Wisconsin owing to an overall lack in life history information, so our study utilized partial redundancy analysis (RDA) and spatially lagged regressions to quantify how three landscape factors (Wisconsin River, Ecoregions and land cover) impacted gene flow. We also performed simulations to quantify errors created by spatially biased sampling. Statistical analyses first found that geographic distance was an important influence on gene flow, mainly driven by fine-scale positive spatial autocorrelations. After controlling for geographic distance, both RDA and regressions found that Wisconsin River and Agriculture were correlated with genetic differentiation. However, only Agriculture had an acceptable type I error rate (3–5%) to be considered biologically relevant. Collectively, this study highlights the benefits of combining robust statistics and error assessment via simulations and provides a method for hypothesis testing in individual-based landscape genetics. PMID:26243136

Biodiversity and ecosystem function in species-poor communities: community structure and leaf litter breakdown in a Pacific island stream

Treesearch

Jonathan P. Benstead; James G. March; Catherine M. Pringle; Katherine C. Ewel; John W. Short

2009-01-01

Pacific island stream communities are species-poor because of the effects of extreme geographic isolation on colonization rates of taxa common to continental regions. The effects of such low species richness on stream ecosystem function are not well understood. Here, we provide data on community structure and leaf litter breakdown rate in a virtually pristine stream on...

Influence of gender on attention-deficit/hyperactivity disorder in Europe--ADORE.

PubMed

Nøvik, Torunn Stene; Hervas, Amaia; Ralston, Stephen J; Dalsgaard, Søren; Rodrigues Pereira, Rob; Lorenzo, Maria J

2006-12-01

Attention-deficit/hyperactivity disorder (ADHD) in girls in Europe is poorly understood; it is not known whether they exhibit similar symptom patterns or co-existing problems and receive the same type of treatment as boys. To examine gender differences for referral patterns, social demographic factors, ADHD core symptomatology, co-existing health problems, psychosocial functioning and treatment. Baseline data from the ADHD Observational Research in Europe (ADORE) study, a 24-month, naturalistic, longitudinal observational study in 10 European countries of children (aged 6-18 years) with hyperactive/inattentive/impulsive symptoms but no previous diagnosis of ADHD, were analysed by gender. Data from 1,478 children were analysed: 231 girls (15.7%) and 1,222 boys (84.3%) (gender data missing for 25 patients). Gender ratios (girl:boy) varied by country, ranging from 1:3 to 1:16. Comparisons showed few gender effects in core ADHD symptomatology and clinical correlates of ADHD. Compared with boys, girls had significantly more parent-rated emotional symptoms and prosocial behaviour and were more likely to be the victim of bullying and less likely to be the bully. Girls and boys had similar levels of co-existing psychiatric and physical health problems, and received the same type of treatment. Fewer girls than boys are referred for ADHD treatment, but they have a similar pattern of impairment and receive similar treatment.

The public's belief about biology.

PubMed

Wolpert, L

2007-02-01

This short review is concerned with a topic that has been neglected and is still very poorly understood: what the general public think and believe about biology (including health and medicine, and bioethics), and, in particular, about biotechnology.

A Production Function Approach to Regional Environmental-Economic Assessments

EPA Science Inventory

Numerous difficulties await those creating regional-scale environmental assessments, from data having inconsistent spatial or temporal scales to poorly understood environmental processes and indicators. Including socioeconomic variables further complicates the situation. In place...

Sleep-wake disturbances in sporadic Creutzfeldt-Jakob disease.

PubMed

Landolt, H-P; Glatzel, M; Blättler, T; Achermann, P; Roth, C; Mathis, J; Weis, J; Tobler, I; Aguzzi, A; Bassetti, C L

2006-05-09

The prevalence and characteristics of sleep-wake disturbances in sporadic Creutzfeldt-Jakob disease (sCJD) are poorly understood. Seven consecutive patients with definite sCJD underwent a systematic assessment of sleep-wake disturbances, including clinical history, video-polysomnography, and actigraphy. Extent and distribution of neurodegeneration was estimated by brain autopsy in six patients. Western blot analyses enabling classification and quantification of the protease-resistant isoform of the prion protein, PrPSc, in thalamus and occipital cortex was available in four patients. Sleep-wake symptoms were observed in all patients, and were prominent in four of them. All patients had severe sleep EEG abnormalities with loss of sleep spindles, very low sleep efficiency, and virtual absence of REM sleep. The correlation between different methods to assess sleep-wake functions (history, polysomnography, actigraphy, videography) was generally poor. Brain autopsy revealed prominent changes in cortical areas, but only mild changes in the thalamus. No mutation of the PRNP gene was found. This study demonstrates in sporadic Creutzfeldt-Jakob disease, first, the existence of sleep-wake disturbances similar to those reported in fatal familial insomnia in the absence of prominent and isolated thalamic neuronal loss, and second, the need of a multimodal approach for the unambiguous assessment of sleep-wake functions in these patients.

The evolution of transcriptional regulation in eukaryotes

NASA Technical Reports Server (NTRS)

Wray, Gregory A.; Hahn, Matthew W.; Abouheif, Ehab; Balhoff, James P.; Pizer, Margaret; Rockman, Matthew V.; Romano, Laura A.

2003-01-01

Gene expression is central to the genotype-phenotype relationship in all organisms, and it is an important component of the genetic basis for evolutionary change in diverse aspects of phenotype. However, the evolution of transcriptional regulation remains understudied and poorly understood. Here we review the evolutionary dynamics of promoter, or cis-regulatory, sequences and the evolutionary mechanisms that shape them. Existing evidence indicates that populations harbor extensive genetic variation in promoter sequences, that a substantial fraction of this variation has consequences for both biochemical and organismal phenotype, and that some of this functional variation is sorted by selection. As with protein-coding sequences, rates and patterns of promoter sequence evolution differ considerably among loci and among clades for reasons that are not well understood. Studying the evolution of transcriptional regulation poses empirical and conceptual challenges beyond those typically encountered in analyses of coding sequence evolution: promoter organization is much less regular than that of coding sequences, and sequences required for the transcription of each locus reside at multiple other loci in the genome. Because of the strong context-dependence of transcriptional regulation, sequence inspection alone provides limited information about promoter function. Understanding the functional consequences of sequence differences among promoters generally requires biochemical and in vivo functional assays. Despite these challenges, important insights have already been gained into the evolution of transcriptional regulation, and the pace of discovery is accelerating.

Blaming the helpers: the marginalization of teachers and parents of the urban poor.

PubMed

Farber, B A; Azar, S T

1999-10-01

The nature and origins of the current tendency toward disparaging parents and teachers of the urban poor are examined. It is suggested that the influence of parents and teachers must be understood in the context of multiple intervening variables. Several explanations are offered for the phenomenon of blame, including the fact that women constitute the great majority of teachers and are often the primary agents of parenting.

PHYTOASSESSMENT OF ESTUARINE SEDIMENTS

EPA Science Inventory

Most sediment quality assessments and quality guidelines are based on the laboratory response of single animal species and benthic animal community composition. The role of plants in this hazard assessment process is poorly understood despite the fact that plant-dominated habitat...

FACTORS INFLUENCING LIGHT-INDUCED MORTALITY OF ENTEROCOCCI IN SEDIMENT SUSPENSIONS

EPA Science Inventory

Contamination of recreational waters by pathogenic microorganisms occurs through complex, poorly understood interactions involving variable microbial sources, hydrodynamic transport, arid microbial fate processes. Fecal indicator bacteria such as enterococci have been used to ass...

Plantation management intensity affects belowground carbon and nitrogen storage in northern California

Treesearch

K. J. McFarlane; S. H. Schoenholtz; R. F. Powers

2009-01-01

Belowground C and N storage is important in maintaining forestproductivity and to CO2 sequestration. How these pools respondto management is poorly understood. We investigated effectsof repeated applications of complete fertilizer and competing...

Predictive Models of Liver Cancer

EPA Science Inventory

Predictive models of chemical-induced liver cancer face the challenge of bridging causative molecular mechanisms to adverse clinical outcomes. The latent sequence of intervening events from chemical insult to toxicity are poorly understood because they span multiple levels of bio...

What Can Plasticity Contribute to Insect Responses to Climate Change?

PubMed

Sgrò, Carla M; Terblanche, John S; Hoffmann, Ary A

2016-01-01

Plastic responses figure prominently in discussions on insect adaptation to climate change. Here we review the different types of plastic responses and whether they contribute much to adaptation. Under climate change, plastic responses involving diapause are often critical for population persistence, but key diapause responses under dry and hot conditions remain poorly understood. Climate variability can impose large fitness costs on insects showing diapause and other life cycle responses, threatening population persistence. In response to stressful climatic conditions, insects also undergo ontogenetic changes including hardening and acclimation. Environmental conditions experienced across developmental stages or by prior generations can influence hardening and acclimation, although evidence for the latter remains weak. Costs and constraints influence patterns of plasticity across insect clades, but they are poorly understood within field contexts. Plastic responses and their evolution should be considered when predicting vulnerability to climate change-but meaningful empirical data lag behind theory.

Activity-Induced Remodeling of Olfactory Bulb Microcircuits Revealed by Monosynaptic Tracing

PubMed Central

Arenkiel, Benjamin R.; Hasegawa, Hiroshi; Yi, Jason J.; Larsen, Rylan S.; Wallace, Michael L.; Philpot, Benjamin D.; Wang, Fan; Ehlers, Michael D.

2011-01-01

The continued addition of new neurons to mature olfactory circuits represents a remarkable mode of cellular and structural brain plasticity. However, the anatomical configuration of newly established circuits, the types and numbers of neurons that form new synaptic connections, and the effect of sensory experience on synaptic connectivity in the olfactory bulb remain poorly understood. Using in vivo electroporation and monosynaptic tracing, we show that postnatal-born granule cells form synaptic connections with centrifugal inputs and mitral/tufted cells in the mouse olfactory bulb. In addition, newly born granule cells receive extensive input from local inhibitory short axon cells, a poorly understood cell population. The connectivity of short axon cells shows clustered organization, and their synaptic input onto newborn granule cells dramatically and selectively expands with odor stimulation. Our findings suggest that sensory experience promotes the synaptic integration of new neurons into cell type-specific olfactory circuits. PMID:22216277

The Multifactorial Epidemiology of Blackwater Fever.

PubMed

Shanks, G Dennis

2017-12-01

Blackwater fever is a massive hemolytic event usually occurring in the context of repeated falciparum malaria infections and intermittent quinine use. Its etiology is poorly understood, and it is rarely seen today. Historical epidemiological observations from the 20th century demonstrated variable patterns in prisoners in Andaman Islands, refugees in Macedonia, canal workers in Panama, expatriates in Rhodesia, and Second World War soldiers. Rates of blackwater fever per 1,000 malaria cases varied over two orders of magnitude. Islands, such as the Andaman Islands and New Guinea, had lower blackwater fever rates than continental areas. During the Second World War, blackwater fever rates in British soldiers in West Africa and Australian soldiers in New Guinea differed by a factor of 40 despite similar treatment regimens and falciparum malaria transmission risks. Blackwater fever is a complex interaction between host erythrocyte, falciparum malaria, and antimalarial drugs which remains poorly understood.

Desiccation stress and tolerance in green algae: consequences for ultrastructure, physiological and molecular mechanisms

PubMed Central

Holzinger, Andreas; Karsten, Ulf

2013-01-01

Although most green algae typically occur in aquatic ecosystems, many species also live partly or permanently under aeroterrestrial conditions, where the cells are exposed to the atmosphere and hence regularly experience dehydration. The ability of algal cells to survive in an air-dried state is termed desiccation tolerance. The mechanisms involved in desiccation tolerance of green algae are still poorly understood, and hence the aim of this review is to summarize recent findings on the effects of desiccation and osmotic water loss. Starting from structural changes, physiological, and biochemical consequences of desiccation will be addressed in different green-algal lineages. The available data clearly indicate a range of strategies, which are rather different in streptophycean and non-streptophycean green algae. While members of the Trebouxiophyceae exhibit effective water loss-prevention mechanisms based on the biosynthesis and accumulation of particular organic osmolytes such as polyols, these compounds are so far not reported in representatives of the Streptophyta. In members of the Streptophyta such as Klebsormidium, the most striking observation is the appearance of cross-walls in desiccated samples, which are strongly undulating, suggesting a high degree of mechanical flexibility. This aids in maintaining structural integrity in the dried state and allows the cell to maintain turgor pressure for a prolonged period of time during the dehydration process. Physiological strategies in aeroterrestrial green algae generally include a rapid reduction of photosynthesis during desiccation, but also a rather quick recovery after rewetting, whereas aquatic species are sensitive to drying. The underlying mechanisms such as the affected molecular components of the photosynthetic machinery are poorly understood in green algae. Therefore, modern approaches based on transcriptomics, proteomics, and/or metabolomics are urgently needed to better understand the molecular mechanisms involved in desiccation-stress physiology of these organisms. The very limited existing information is described in the present review. PMID:23986769

How do respiratory patients perceive oxygen therapy? A critical interpretative synthesis of the literature.

PubMed

Kelly, Carol Ann; Maden, Michelle

2014-11-01

Oxygen therapy is a common intervention in health care worldwide; yet, despite universal use, it is evident through poor practice that oxygen is often prescribed and administered injudiciously. It is proposed that possibly an influencing culture presides, whereby oxygen is often poorly understood and uncertainty regarding its use exists. It is unclear where the origins of this culture lie but exploring perceptions may enlighten the problem. A review of the literature was undertaken to establish what is already known about this elusive phenomenon. The paucity of any direct evidence regarding perceptions of oxygen directed the review to utilize a critical interpretative synthesis (CIS). The aim of this study was to explore how respiratory patients perceive oxygen therapy. A systematic search in Medline, Cinahl, Embase, British Nursing Index and PsychInfo yielded 1514 studies of which 42 were selected to consider the review question. The CIS allowed evidence from across studies to synthesize existing and new interpretations of data related to patients' perceptions of oxygen therapy. Synthetic constructs then informed the synthesizing arguments, namely positive - feeling safe, enabler and comforter; negative - fear, oxygen versus self, restriction and embarrassment; and impartiality - mixed blessings. The findings are divergent, and at times contradictory. There appears uncertainty among patients regarding the purpose and benefits of oxygen therapy, though an underlying faith in health-care professionals is apparent. This faith seems to foster acceptance of a life-changing therapy, despite the impact, burden and incomplete understanding. There is a clear need for further research regarding these elusive perceptions in order to improve clinical practice in respect of oxygen. © The Author(s) 2014.

"It's not really worth my while": understanding contextual factors contributing to decisions to participate in community aphasia groups.

PubMed

Lanyon, Lucette; Worrall, Linda; Rose, Miranda

2018-01-10

Community aphasia groups represent a formalised opportunity for social participation. The potential barriers and facilitators to accessing and maintaining group participation remain poorly understood. The aim of this study was to explore environmental and personal factors contributing to community aphasia group participation. A framework analysis (FA) was used to analyse the semi-structured interview data from 22 current and past members of community aphasia groups. People with aphasia weigh up the benefits of group participation in the context of a range of personal and environmental factors. These include personal coping mechanisms, perceptions of existing social support as well as the practicalities of accessing the group. Understanding factors that contribute to participation experiences is critical to ensure that, people with aphasia are well supported to access and engage in community aphasia groups. This study found that people may be more able to participate when they are accepting of the chronic nature of the aphasia, when they identify tangible benefits to participation, and when they have easy access to the group. This suggests a role for speech pathologists to recognise critical periods of need and support people with aphasia and their significant others to access and engage in group services. Implications for Rehabilitation Critical stages exist when people with aphasia may feel more ready and able to participate in community aphasia groups. These critical stages include an acceptance of the chronic nature of aphasia, as well as a desire to make positive change. There is a need for clinicians to minimise barriers to participation early in the therapeutic relationship. Proliferation of community aphasia groups will function to alleviate environmental barriers associated with poor public awareness of groups and group accessibility.

Spoiled breast milk and bad water; local understandings of diarrhea causes and prevention in rural Sierra Leone.

PubMed

McMahon, Shannon A; George, Asha S; Yumkella, Fatu; Diaz, Theresa

2013-12-13

Globally, diarrhea remains a leading killer of young children. In Sierra Leone, one in seven children die before their fifth birthday and diarrhea is a leading cause. Studies that emphasize the demand-side of health interventions -- how caregivers understand causation and prevention of diarrhea -- have been neglected in research and programming. We undertook applied qualitative research including 68 in-depth interviews and 36 focus group discussions with mothers, fathers and older female caretakers to examine the causes and prevention of childhood diarrhea in villages near and far from health facilities across four rural districts. Verbal consent was obtained. Respondents reported multiple, co-existing descriptions of causation including: contaminated water and difficulties accessing clean water; exposure to an unclean environment and poor food hygiene; contaminated breast milk due to sexual intercourse, overheated breast milk or bodily maternal conditions such as menstruation or pregnancy; and dietary imbalances and curses. Respondents rarely discussed the role of open defecation or the importance of handwashing with soap in preventing diarrhea. Categorizing behaviors as beneficial, harmful, non-existent or benign enables tailored programmatic recommendations. For example, respondents recognized the value of clean water and we correspondingly recommend interventions that reinforce consumption of and access to clean water. Second, respondents report denying "contaminated" breast milk to breastfeeding children. This is a harmful practice that merits attention. Third, the role of open defecation and poor hygiene in causing diarrhea is less understood and warrants introduction or clarification. Finally, the role of exposed feet or curses in causing diarrhea is relatively benign and does not necessitate programmatic attention. Further research supportive of communication and social mobilization strategies building on these findings is required to ensure that improved understanding regarding diarrhea causation translates into improved diarrhea prevention.

Spoiled breast milk and bad water; local understandings of diarrhea causes and prevention in rural Sierra Leone

PubMed Central

2013-01-01

Background Globally, diarrhea remains a leading killer of young children. In Sierra Leone, one in seven children die before their fifth birthday and diarrhea is a leading cause. Studies that emphasize the demand-side of health interventions -- how caregivers understand causation and prevention of diarrhea -- have been neglected in research and programming. Methods We undertook applied qualitative research including 68 in-depth interviews and 36 focus group discussions with mothers, fathers and older female caretakers to examine the causes and prevention of childhood diarrhea in villages near and far from health facilities across four rural districts. Verbal consent was obtained. Results Respondents reported multiple, co-existing descriptions of causation including: contaminated water and difficulties accessing clean water; exposure to an unclean environment and poor food hygiene; contaminated breast milk due to sexual intercourse, overheated breast milk or bodily maternal conditions such as menstruation or pregnancy; and dietary imbalances and curses. Respondents rarely discussed the role of open defecation or the importance of handwashing with soap in preventing diarrhea. Conclusions Categorizing behaviors as beneficial, harmful, non-existent or benign enables tailored programmatic recommendations. For example, respondents recognized the value of clean water and we correspondingly recommend interventions that reinforce consumption of and access to clean water. Second, respondents report denying “contaminated” breast milk to breastfeeding children. This is a harmful practice that merits attention. Third, the role of open defecation and poor hygiene in causing diarrhea is less understood and warrants introduction or clarification. Finally, the role of exposed feet or curses in causing diarrhea is relatively benign and does not necessitate programmatic attention. Further research supportive of communication and social mobilization strategies building on these findings is required to ensure that improved understanding regarding diarrhea causation translates into improved diarrhea prevention. PMID:24330586

Estimating aquifer properties using time-lapse, high precision gravity surveys and groundwater modeling

NASA Astrophysics Data System (ADS)

Keating, E.; Cogbill, A. H.; Ferguson, J. F.

2003-12-01

In the past, gravity methods have had limited application for monitoring aquifers, primarily due to the poor drift characteristics of relative gravimeters, which made long-term gravity studies of aquifers prohibitively expensive. Recent developments in portable, very accurate, absolute gravity instruments having essentially zero long-term drift have reawakened interest in using gravity methods for hydrologic monitoring. Such instruments have accuracies of 7 microGals or better and can acquire measurements at the rate of better than one station per hour. Theoretically, temporal changes in gravity can be used to infer storage characteristics and fluxes into and out of the aquifer. The sensitivity of the method to scaling effects, temporal lags between recharge/discharge and changes in storage, and to uncertainties in aquifer structure are poorly understood. In preparation for interpreting a basin-scale, time-lapse gravity data set, we have established a network of gravity stations within the Espanola Basin in northern New Mexico, a semi-arid region which is experiencing rapid population growth and groundwater resource use. We are using an existing basin-scale groundwater flow model to predict changes in mass, given our current level of understanding of inflows, outflows, and aquifer properties. Preliminary model results will be used to examine scaling issues related to the spatial density of the gravity station network and depths to the regional water table. By modeling the gravitational response to water movement in the aquifer, we study the sensitivity of gravity measurements to aquifer storage properties, given other known uncertainties in basin-scale fluxes. Results will be used to evaluate the adequacy of the existing network and to modify its design, if necessary.

Tracking contaminant flux from aquatic to terrestrial food webs

EPA Science Inventory

Aquatic insects provide a critical energy subsidy to riparian food webs, yet their role as vectors of contaminants to terrestrial ecosystems is poorly understood. We investigated aquatic resource utilization and contaminant exposure among riparian invertivores (spiders and herpt...

Asthma and Respiratory Allergic Disease

EPA Science Inventory

The pathogenesis of non-communicable diseases such as allergy is complex and poorly understood. The causes of chronic allergic diseases including asthma involve to a large extent, immunomodulation of the adaptive and particularly the innate immune systems and are markedly influen...

A Production Function Approach to Regional Environmental Economic Assessments

EPA Science Inventory

Regional-scale environmental assessments require integrating many available types of data having inconsistent spatial or temporal scales. Moreover, the relationships among the environmental variables in the assessment tend to be poorly understood, a situation made even more compl...

AtCHX13 is a plasma membrane K(+) transporter

USDA-ARS?s Scientific Manuscript database

Potassium (K+) homeostasis is essential for diverse cellular processes, although how various cation transporters collaborate to maintain a suitable K(+) required for growth and development is poorly understood. The Arabidopsis ("Arabidopsis thaliana") genome contains numerous cation:proton antiporte...

AtCHX13 is a plasma membrane K+ transporter

USDA-ARS?s Scientific Manuscript database

Potassium (K+) homeostasis is essential for diverse cellular processes, although how various cation transporters collaborate to maintain a suitable K+ required for growth and development is poorly understood. The Arabidopsis (Arabidopsis thaliana) genome contains numerous cation:proton antiporters (...

The 2011 National Wetland Condition Assessment

EPA Science Inventory

The ecological condition of wetland resources across the conterminous United States is poorly understood. To address this issue, the U.S. Environmental Protection Agency (USEPA), in collaboration with states, tribes, and other federal partners, is conducting the first-ever Natio...

Impacts of Human Activity on the Microbial Communities of Devon Island, Canadian High Arctic

NASA Astrophysics Data System (ADS)

Bywaters, K. B.; Burton, A. S.; Wallace, S. L.; Glass, B. J.

2016-09-01

The impacts of human activities on microbial communities in arctic environments are poorly understood. This project compares the distribution of microbes at the HMP Mars analog site prior to and after human settlement.

AN IMPROVED METHOD FOR DETECTING VIRUSES IN WATER

EPA Science Inventory

Enteroviruses are important etiological agents of waterborne disease and are responsible for outbreaks of gastroenteritis. However, the prevalence and occurrence of these pathogens in raw drinking water sources is poorly understood. This is primarily due to the limited methods ...

The mechanisms of intrarenal hemodynamic changes following acute arterial occlusion.

DOT National Transportation Integrated Search

1963-10-01

The hemodynamic response of the kidney to acute arterial occlusion is poorly understood. The purpose of the present study was to determine intrarenal hemodynamic changes in intact and isolated kidneys following arterial occlusion. : The relative role...

Prediction of Membership in Rehabilitation Counseling Professional Associations

ERIC Educational Resources Information Center

Phillips, Brian N.; Leahy, Michael J.

2012-01-01

Declining membership is a concerning yet poorly understood issue affecting professional associations across disciplines (Bauman, 2008). Rehabilitation counseling association membership is in decline even while number of certified rehabilitation counselors continues to increase (Leahy, 2009). Factors influencing rehabilitation counseling…

The prevalence and causes of autistic spectrum disorders.

PubMed

Hainsworth, Terry

Autism and autistic spectrum disorders are still relatively poorly understood. This article outlines the results of new research into the prevalence of autism and into the causes of the condition and highlights implications for nurses from the findings.

Familiarity and Aptness in Metaphor Comprehension.

PubMed

Damerall, Alison Whiteford; Kellogg, Ronald T

2016-01-01

The career of metaphor hypothesis suggests that novel metaphors are understood through a search for shared features between the topic and vehicle, but with repeated exposure, the figurative meaning is understood directly as a new category is established. The categorization hypothesis argues that instead good or apt metaphors are understood through a categorization process, whether or not they are familiar. Only poor metaphors ever invoke a literal comparison. In Experiment 1, with aptness equated, we found that high familiarity speeded comprehension time over low-familiarity metaphors. In Experiment 2a, providing a literal prime failed to facilitate interpretation of low-familiarity metaphors, contrary to the career of metaphor hypothesis. In Experiment 2b, with familiarity equated, high- and low-aptness metaphors did not differ, contrary to the categorization hypothesis.

Loneliness in psychosis: a systematic review.

PubMed

Lim, Michelle H; Gleeson, John F M; Alvarez-Jimenez, Mario; Penn, David L

2018-03-01

The aim of the review is to understand the relationships between loneliness and related psychological and social factors in individuals with psychosis. Loneliness is poorly understood in people with psychosis. Given the myriad of social challenges facing individuals with psychosis, these findings can inform psychosocial interventions that specifically target loneliness in this vulnerable group. We adhered to the PRISMA guidelines and systematically reviewed empirical studies that measured loneliness either as a main outcome or as an associated variable in individuals with psychosis. A total of ten studies examining loneliness in people diagnosed with a psychotic disorder were examined. Heterogeneity in the assessment of loneliness was found, and there were contradictory findings on the relationship between loneliness and psychotic symptomatology. In individuals with psychosis, loneliness may be influenced by psychological and social factors such as increased depression, psychosis, and anxiety, poor social support, poor quality of life, more severe internalised stigma and perceived discrimination, and low self-esteem. The relationship between loneliness and psychosis remains poorly understood due to a lack of rigorous studies. Although having strong social relationships is crucial to facilitate recovery from serious mental illness, psychosocial interventions that specifically target loneliness in individuals with psychosis are lacking and sorely needed. Interventions targeting loneliness in those with psychosis will also need to account for additional barriers associated with psychosis (e.g., social skill deficits, impoverished social networks, and negative symptoms).

Late Maturation Steps Preceding Selective Nuclear Export and Egress of Progeny Parvovirus

PubMed Central

Wolfisberg, Raphael; Kempf, Christoph

2016-01-01

ABSTRACT Although the mechanism is not well understood, growing evidence indicates that the nonenveloped parvovirus minute virus of mice (MVM) may actively egress before passive release through cell lysis. We have dissected the late maturation steps of the intranuclear progeny with the aims of confirming the existence of active prelytic egress and identifying critical capsid rearrangements required to initiate the process. By performing anion-exchange chromatography (AEX), we separated intranuclear progeny particles by their net surface charges. Apart from empty capsids (EC), two distinct populations of full capsids (FC) arose in the nuclei of infected cells. The earliest population of FC to appear was infectious but, like EC, could not be actively exported from the nucleus. Further maturation of this early population, involving the phosphorylation of surface residues, gave rise to a second, late population with nuclear export potential. While capsid surface phosphorylation was strictly associated with nuclear export capacity, mutational analysis revealed that the phosphoserine-rich N terminus of VP2 (N-VP2) was dispensable, although it contributed to passive release. The reverse situation was observed for the incoming particles, which were dephosphorylated in the endosomes. Our results confirm the existence of active prelytic egress and reveal a late phosphorylation event occurring in the nucleus as a selective factor for initiating the process. IMPORTANCE In general, the process of egress of enveloped viruses is active and involves host cell membranes. However, the release of nonenveloped viruses seems to rely more on cell lysis. At least for some nonenveloped viruses, an active process before passive release by cell lysis has been reported, although the underlying mechanism remains poorly understood. By using the nonenveloped model parvovirus minute virus of mice, we could confirm the existence of an active process of nuclear export and further characterize the associated capsid maturation steps. Following DNA packaging in the nucleus, capsids required further modifications, involving the phosphorylation of surface residues, to acquire nuclear export potential. Inversely, those surface residues were dephosphorylated on entering capsids. These spatially controlled phosphorylation-dephosphorylation events concurred with the nuclear export-import potential required to complete the infectious cycle. PMID:27009963

Late Maturation Steps Preceding Selective Nuclear Export and Egress of Progeny Parvovirus.

PubMed

Wolfisberg, Raphael; Kempf, Christoph; Ros, Carlos

2016-06-01

Although the mechanism is not well understood, growing evidence indicates that the nonenveloped parvovirus minute virus of mice (MVM) may actively egress before passive release through cell lysis. We have dissected the late maturation steps of the intranuclear progeny with the aims of confirming the existence of active prelytic egress and identifying critical capsid rearrangements required to initiate the process. By performing anion-exchange chromatography (AEX), we separated intranuclear progeny particles by their net surface charges. Apart from empty capsids (EC), two distinct populations of full capsids (FC) arose in the nuclei of infected cells. The earliest population of FC to appear was infectious but, like EC, could not be actively exported from the nucleus. Further maturation of this early population, involving the phosphorylation of surface residues, gave rise to a second, late population with nuclear export potential. While capsid surface phosphorylation was strictly associated with nuclear export capacity, mutational analysis revealed that the phosphoserine-rich N terminus of VP2 (N-VP2) was dispensable, although it contributed to passive release. The reverse situation was observed for the incoming particles, which were dephosphorylated in the endosomes. Our results confirm the existence of active prelytic egress and reveal a late phosphorylation event occurring in the nucleus as a selective factor for initiating the process. In general, the process of egress of enveloped viruses is active and involves host cell membranes. However, the release of nonenveloped viruses seems to rely more on cell lysis. At least for some nonenveloped viruses, an active process before passive release by cell lysis has been reported, although the underlying mechanism remains poorly understood. By using the nonenveloped model parvovirus minute virus of mice, we could confirm the existence of an active process of nuclear export and further characterize the associated capsid maturation steps. Following DNA packaging in the nucleus, capsids required further modifications, involving the phosphorylation of surface residues, to acquire nuclear export potential. Inversely, those surface residues were dephosphorylated on entering capsids. These spatially controlled phosphorylation-dephosphorylation events concurred with the nuclear export-import potential required to complete the infectious cycle. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Continuous-variable quantum key distribution protocols over noisy channels.

PubMed

García-Patrón, Raúl; Cerf, Nicolas J

2009-04-03

A continuous-variable quantum key distribution protocol based on squeezed states and heterodyne detection is introduced and shown to attain higher secret key rates over a noisy line than any other one-way Gaussian protocol. This increased resistance to channel noise can be understood as resulting from purposely adding noise to the signal that is converted into the secret key. This notion of noise-enhanced tolerance to noise also provides a better physical insight into the poorly understood discrepancies between the previously defined families of Gaussian protocols.

Predictive Models of Nanotoxicity: Relationship of Physicochemical Properties to Particle Movement Through Biological Barriers

EPA Science Inventory

Understanding the linkage between the physicochemical (PC) properties of nanoparticles (NP) and their activation of biological systems is poorly understood, yet fundamental to predicting nanotoxicity, idenitifying mode of actions and developing appropriate and effective regul...

Physiological benefits of nectar-feeding by a predatory beetle

USDA-ARS?s Scientific Manuscript database

Extrafloral nectar is an important food source for many animals, including predatory lady beetles (Coleoptera: Coccinellidae), although the physiological benefits of nectar consumption are poorly understood for most consumers. Under laboratory conditions, we confined new females of Coleomegilla macu...

Fructose, high fructose corn syrup, sucrose, and non-alcoholic liver disease

USDA-ARS?s Scientific Manuscript database

Nonalcoholic fatty liver disease (NAFLD), formerly called nonalcoholic steatohepatitis, is characterized by hepatic steatosis and abnormal triglyceride accumulation in liver cells. Its etiology, pathophysiology, and pathogenesis are still poorly understood. Some have suggested that the increased in...

Salary, Performance, and Superintendent Turnover

ERIC Educational Resources Information Center

Grissom, Jason A.; Mitani, Hajime

2016-01-01

Purpose: Superintendent retention is an important goal for many school districts, yet the factors contributing to superintendent turnover are poorly understood. Most prior quantitative studies of superintendent turnover have relied on small, cross-sectional samples, limiting the evidence base. Utilizing longitudinal administrative records from…

New perspectives on microbial community distortion after whole-genome amplification

EPA Science Inventory

Whole-genome amplification (WGA) has become an important tool to explore the genomic information of microorganisms in an environmental sample with limited biomass, however potential selective biases during the amplification processes are poorly understood. Here, we describe the e...

Ankle ligament injuries.

PubMed

Abbassian, Ali; Thomas, Rhidian

2008-06-01

Ankle ligament injuries in the presence or in the absence of fractures are common. They often present a diagnostic challenge, and their management is poorly understood and subject to debate. This article reviews and discusses the current literature on the management and diagnosis of these injuries.

Pedagogical Play Types: What Do They Suggest for Learning about Sustainability in Early Childhood Education?

ERIC Educational Resources Information Center

Edwards, Susan; Cutter-Mackenzie, Amy

2013-01-01

Sustainability education is increasingly understood as necessary for young children. An important aspect of early childhood sustainability education is associated with how best to integrate the conceptual basis of sustainability education with existing play-based pedagogies. Play-based pedagogies can be understood as occurring along a continuum,…

Accurately Characterizing the Importance of Wave-Particle Interactions in Radiation Belt Dynamics: The Pitfalls of Statistical Wave Representations

NASA Technical Reports Server (NTRS)

Murphy, Kyle R.; Mann, Ian R.; Rae, I. Jonathan; Sibeck, David G.; Watt, Clare E. J.

2016-01-01

Wave-particle interactions play a crucial role in energetic particle dynamics in the Earths radiation belts. However, the relative importance of different wave modes in these dynamics is poorly understood. Typically, this is assessed during geomagnetic storms using statistically averaged empirical wave models as a function of geomagnetic activity in advanced radiation belt simulations. However, statistical averages poorly characterize extreme events such as geomagnetic storms in that storm-time ultralow frequency wave power is typically larger than that derived over a solar cycle and Kp is a poor proxy for storm-time wave power.

Perfectionism related to self-reported insomnia severity, but not when controlled for stress and emotion regulation.

PubMed

Brand, Serge; Kirov, Roumen; Kalak, Nadeem; Gerber, Markus; Pühse, Uwe; Lemola, Sakari; Correll, Christoph U; Cortese, Samuele; Meyer, Till; Holsboer-Trachsler, Edith

2015-01-01

Perfectionism is understood as a set of personality traits such as unrealistically high and rigid standards for performance, fear of failure, and excessive self-criticism. Previous studies showed a direct association between increased perfectionism and poor sleep, though without taking into account possible mediating factors. Here, we tested the hypothesis that perfectionism was directly associated with poor sleep, and that this association collapsed, if mediating factors such as stress and poor emotion regulation were taken into account. Three hundred and forty six young adult students (M=23.87 years) completed questionnaires relating to perfectionism traits, sleep, and psychological functioning such as stress perception, coping with stress, emotion regulation, and mental toughness. Perfectionism was directly associated with poor sleep and poor psychological functioning. When stress, poor coping, and poor emotion regulation were entered in the equation, perfectionism traits no longer contributed substantively to the explanation of poor sleep. Though perfectionism traits seem associated with poor sleep, the direct role of such traits seemed small, when mediating factors such as stress perception and emotion regulation were taken into account.

Perfectionism related to self-reported insomnia severity, but not when controlled for stress and emotion regulation

PubMed Central

Brand, Serge; Kirov, Roumen; Kalak, Nadeem; Gerber, Markus; Pühse, Uwe; Lemola, Sakari; Correll, Christoph U; Cortese, Samuele; Meyer, Till; Holsboer-Trachsler, Edith

2015-01-01

Background Perfectionism is understood as a set of personality traits such as unrealistically high and rigid standards for performance, fear of failure, and excessive self-criticism. Previous studies showed a direct association between increased perfectionism and poor sleep, though without taking into account possible mediating factors. Here, we tested the hypothesis that perfectionism was directly associated with poor sleep, and that this association collapsed, if mediating factors such as stress and poor emotion regulation were taken into account. Methods Three hundred and forty six young adult students (M=23.87 years) completed questionnaires relating to perfectionism traits, sleep, and psychological functioning such as stress perception, coping with stress, emotion regulation, and mental toughness. Results Perfectionism was directly associated with poor sleep and poor psychological functioning. When stress, poor coping, and poor emotion regulation were entered in the equation, perfectionism traits no longer contributed substantively to the explanation of poor sleep. Conclusion Though perfectionism traits seem associated with poor sleep, the direct role of such traits seemed small, when mediating factors such as stress perception and emotion regulation were taken into account. PMID:25678791

Discrimination and the health of immigrants and refugees: exploring Canada's evidence base and directions for future research in newcomer receiving countries.

PubMed

Edge, Sara; Newbold, Bruce

2013-02-01

Research and practice increasingly suggests discrimination compromises health. Yet the unique experiences and effects facing immigrant and refugee populations remain poorly understood in Canada and abroad. We review current knowledge on discrimination against newcomers in Canada, emphasizing impacts upon health status and service access to identify gaps and research needs. Existing knowledge centers around experiences within health-care settings, differences in perception and coping, mental health impacts, and debates about "non-discriminatory" health-care. There is need for comparative analyses within and across ethno-cultural groups and newcomer classes to better understand factors shaping how discrimination and its health effects are differentially experienced. Women receive greater attention in the literature given their compounded vulnerability. While this must continue, little is known about the experiences of youth and men. Governance and policy discourse analyses would elucidate how norms, institutions and practices shape discriminatory attitudes and responses. Finally, "non-discriminatory health-care" interventions require critical evaluation to determine their effectiveness.

Epigenome confrontation triggers immediate reprogramming of DNA methylation and transposon silencing in Arabidopsis thaliana F1 epihybrids

PubMed Central

Rigal, Mélanie; Becker, Claude; Pélissier, Thierry; Pogorelcnik, Romain; Devos, Jane; Ikeda, Yoko; Weigel, Detlef; Mathieu, Olivier

2016-01-01

Genes and transposons can exist in variable DNA methylation states, with potentially differential transcription. How these epialleles emerge is poorly understood. Here, we show that crossing an Arabidopsis thaliana plant with a hypomethylated genome and a normally methylated WT individual results, already in the F1 generation, in widespread changes in DNA methylation and transcription patterns. Novel nonparental and heritable epialleles arise at many genic loci, including a locus that itself controls DNA methylation patterns, but with most of the changes affecting pericentromeric transposons. Although a subset of transposons show immediate resilencing, a large number display decreased DNA methylation, which is associated with de novo or enhanced transcriptional activation and can translate into transposon mobilization in the progeny. Our findings reveal that the combination of distinct epigenomes can be viewed as an epigenomic shock, which is characterized by a round of epigenetic variation creating novel patterns of gene and TE regulation. PMID:27001853

FUSE Cycle 3 Program CO22: Chromospheric Activity in Population II Giants

NASA Technical Reports Server (NTRS)

Harper, Graham M.

2004-01-01

One of the mysteries of Population II giants is that they still show chromospheric emission despite their great age. The global dynamo which was active during their main-sequence lifetimes is expected to become extremely weak through magnetic rotational braking. The nature of the observed emission is not understood; although acoustic shock waves might provide the heating, acoustic waves are not predicted to drive the observed mass loss - which in turn requires the dissipation of magneto-hydrodynamic waves. This program was designed to search for the faint stellar H Ly(beta) emission wings and the fluorescent Fe II and H2 emission from one of the brightest, metal poor, Population II stars. These FUSE diagnostics, when combined with existing UV and optical spectra, help determine the major radiative cooling channels for the chromosphere. This observation was to complement that previously planned for the mildly metal deficient giant alpha Boo (K2 III). However, a Boo has yet to be observed with FUSE.

Chromospheric Activity in Population II Giants

NASA Technical Reports Server (NTRS)

Harper, Graham M.

2004-01-01

One of the mysteries of Population II giants is that they still show chromospheric emission despite their great age. The global dynamo which was active during their main-sequence lifetimes is expected to become extremely weak through magnetic rotational braking. The nature of the observed emission is not understood; although acoustic shock waves might provide the heating, acoustic waves are not predicted to drive the observed mass loss - which in turn requires the dissipation of magneto-hydrodynamic waves. This program was designed to search for the faint stellar H Ly beta emission wings and the fluorescent Fe II and H2 emission from one of the brightest, metal poor, Population II stars. These FUSE diagnostics, when combined with existing UV and optical spectra, help determine the major radiative cooling channels for the chromosphere. This observation was to complement that previously planned for the mildly metal deficient giant alpha Boo (K2 III). However, alpha Boo has yet to be observed with FUSE.

Double-Cusp type electrostatic Analyzer for SupraThermal ions (DCAST)

NASA Astrophysics Data System (ADS)

Ogasawara, Keiichi; Livi, Stefano; Desai, Mihir; Allegrini, Frederic; McComas, David; John, Joerg-Micha

2016-04-01

Measurements obtained over the last decade have led to a general consensus that the poorly understood suprathermal (ST) tail between ˜2-100 keV/nucleon provides much of the seed population for CME-driven shocks near the Sun and in the interplanetary space. However, existing instruments are not only resource hungry (e.g., power and mass) but also require very long integration times (>days) to measure key properties of the ST ions e.g., anisotropy, energy spectra, composition, and spatial-temporal variations. Our proposed concept of the electrostatic analyzer, employing a toroidal double-shell structure, covers the ST energy between ˜3-200 keV/q ions with higher temporal resolution while using significantly lower resources compared to conventional solar wind instruments covering ST energy range. In this presentation, we describe the concept and show testing results obtained with our laboratory prototype. We will give the expected performance (G-factor, analyzer constant, energy resolution, cross-shell contamination, and UV suppression) based on measurements and simulations.

Description of a method to support public health information management: organizational network analysis

PubMed Central

Merrill, Jacqueline; Bakken, Suzanne; Rockoff, Maxine; Gebbie, Kristine; Carley, Kathleen

2007-01-01

In this case study we describe a method that has potential to provide systematic support for public health information management. Public health agencies depend on specialized information that travels throughout an organization via communication networks among employees. Interactions that occur within these networks are poorly understood and are generally unmanaged. We applied organizational network analysis, a method for studying communication networks, to assess the method’s utility to support decision making for public health managers, and to determine what links existed between information use and agency processes. Data on communication links among a health department’s staff was obtained via survey with a 93% response rate, and analyzed using Organizational Risk Analyzer (ORA) software. The findings described the structure of information flow in the department’s communication networks. The analysis succeeded in providing insights into organizational processes which informed public health managers’ strategies to address problems and to take advantage of network strengths. PMID:17098480

Evaluation and management of priapism in a newborn: A case report and review of the literature

PubMed Central

Dust, Nicholas; Daboval, Thierry; Guerra, Luis

2011-01-01

Idiopathic neonatal priapism is a rare and poorly understood phenomenon. The case of an otherwise healthy premature male newborn who was noted to have a persistent penile erection on the first day of life is presented. A Doppler ultrasound of the penis was performed, along with the first-ever cavernous blood gas analysis reported in a newborn. These investigations indicated that the presentation was consistent with nonischemic (arterial or high-flow) priapism. The patient was managed conservatively and the erection resolved fully on the sixth day of life. A review of the existing literature identified polycythemia as the most common identifiable cause of priapism in newborns, but the majority of cases are idiopathic. In most instances, observation alone is appropriate and spontaneous detumescence occurs. There are no published reports of erectile impairment following neonatal priapism, which suggests that this condition is relatively benign in the absence of other disease states. PMID:22211080

Galaxy Alignments: Theory, Modelling & Simulations

NASA Astrophysics Data System (ADS)

Kiessling, Alina; Cacciato, Marcello; Joachimi, Benjamin; Kirk, Donnacha; Kitching, Thomas D.; Leonard, Adrienne; Mandelbaum, Rachel; Schäfer, Björn Malte; Sifón, Cristóbal; Brown, Michael L.; Rassat, Anais

2015-11-01

The shapes of galaxies are not randomly oriented on the sky. During the galaxy formation and evolution process, environment has a strong influence, as tidal gravitational fields in the large-scale structure tend to align nearby galaxies. Additionally, events such as galaxy mergers affect the relative alignments of both the shapes and angular momenta of galaxies throughout their history. These "intrinsic galaxy alignments" are known to exist, but are still poorly understood. This review will offer a pedagogical introduction to the current theories that describe intrinsic galaxy alignments, including the apparent difference in intrinsic alignment between early- and late-type galaxies and the latest efforts to model them analytically. It will then describe the ongoing efforts to simulate intrinsic alignments using both N-body and hydrodynamic simulations. Due to the relative youth of this field, there is still much to be done to understand intrinsic galaxy alignments and this review summarises the current state of the field, providing a solid basis for future work.

Folding of a single domain protein entering the endoplasmic reticulum precedes disulfide formation.

PubMed

Robinson, Philip J; Pringle, Marie Anne; Woolhead, Cheryl A; Bulleid, Neil J

2017-04-28

The relationship between protein synthesis, folding, and disulfide formation within the endoplasmic reticulum (ER) is poorly understood. Previous studies have suggested that pre-existing disulfide links are absolutely required to allow protein folding and, conversely, that protein folding occurs prior to disulfide formation. To address the question of what happens first within the ER, that is, protein folding or disulfide formation, we studied folding events at the early stages of polypeptide chain translocation into the mammalian ER using stalled translation intermediates. Our results demonstrate that polypeptide folding can occur without complete domain translocation. Protein disulfide isomerase (PDI) interacts with these early intermediates, but disulfide formation does not occur unless the entire sequence of the protein domain is translocated. This is the first evidence that folding of the polypeptide chain precedes disulfide formation within a cellular context and highlights key differences between protein folding in the ER and refolding of purified proteins. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Medicine's perception of reality - a split picture: critical reflections on apparent anomalies within the biomedical theory of science.

PubMed

Kirkengen, Anna Luise; Ekeland, Tor-Johan; Getz, Linn; Hetlevik, Irene; Schei, Edvin; Ulvestad, Elling; Vetlesen, Arne Johan

2016-08-01

Escalating costs, increasing multi-morbidity, medically unexplained health problems, complex risk, poly-pharmacy and antibiotic resistance can be regarded as artefacts of the traditional knowledge production in Western medicine, arising from its particular worldview. Our paper presents a historically grounded critical analysis of this view. The materialistic shift of Enlightenment philosophy, separating subjectivity from bodily matter, became normative for modern medicine and yielded astonishing results. The traditional dichotomies of mind/body and subjective/objective are, however, incompatible with modern biological theory. Medical knowledge ignores central tenets of human existence, notably the physiological impact of subjective experience, relationships, history and sociocultural contexts. Biomedicine will not succeed in resolving today's poorly understood health problems by doing 'more of the same'. We must acknowledge that health, sickness and bodily functioning are interwoven with human meaning-production, fundamentally personal and biographical. This implies that the biomedical framework, although having engendered 'success stories' like the era of antibiotics, needs to be radically revised. © 2015 John Wiley & Sons, Ltd.

Dynamics of Tumor Heterogeneity Derived from Clonal Karyotypic Evolution.

PubMed

Laughney, Ashley M; Elizalde, Sergi; Genovese, Giulio; Bakhoum, Samuel F

2015-08-04

Numerical chromosomal instability is a ubiquitous feature of human neoplasms. Due to experimental limitations, fundamental characteristics of karyotypic changes in cancer are poorly understood. Using an experimentally inspired stochastic model, based on the potency and chromosomal distribution of oncogenes and tumor suppressor genes, we show that cancer cells have evolved to exist within a narrow range of chromosome missegregation rates that optimizes phenotypic heterogeneity and clonal survival. Departure from this range reduces clonal fitness and limits subclonal diversity. Mapping of the aneuploid fitness landscape reveals a highly favorable, commonly observed, near-triploid state onto which evolving diploid- and tetraploid-derived populations spontaneously converge, albeit at a much lower fitness cost for the latter. Finally, by analyzing 1,368 chromosomal translocation events in five human cancers, we find that karyotypic evolution also shapes chromosomal translocation patterns by selecting for more oncogenic derivative chromosomes. Thus, chromosomal instability can generate the heterogeneity required for Darwinian tumor evolution. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Homogeneity of Powassan virus populations in naturally infected Ixodes scapularis

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

Brackney, Doug E.; Brown, Ivy K.; Nofchissey, Robert A.

2010-07-05

Powassan virus (POWV, Flaviviridae: Flavivirus) is the sole North American member of the tick-borne encephalitis complex and consists of two distinct lineages that are maintained in ecologically discrete enzootic transmission cycles. The underlying genetic mechanisms that lead to niche partitioning in arboviruses are poorly understood. Therefore, intra- and interhost genetic diversity was analyzed to determine if POWV exists as a quasispecies in nature and quantify selective pressures within and between hosts. In contrast to previous reports for West Nile virus (WNV), significant intrahost genetic diversity was not observed. However, pN (0.238) and d{sub N}/d{sub S} ratios (0.092) for interhost diversitymore » were similar to those of WNV. Combined, these data suggest that purifying selection and/or population bottlenecks constrain quasispecies diversity within ticks. These same selective and stochastic mechanisms appear to drive minor sequence changes between ticks. Moreover, Powassan virus populations seem not to be structured as quasispecies in naturally infected adult deer ticks.« less

A long-term epigenetic memory switch controls bacterial virulence bimodality

PubMed Central

Ronin, Irine; Katsowich, Naama; Rosenshine, Ilan; Balaban, Nathalie Q

2017-01-01

When pathogens enter the host, sensing of environmental cues activates the expression of virulence genes. Opposite transition of pathogens from activating to non-activating conditions is poorly understood. Interestingly, variability in the expression of virulence genes upon infection enhances colonization. In order to systematically detect the role of phenotypic variability in enteropathogenic E. coli (EPEC), an important human pathogen, both in virulence activating and non-activating conditions, we employed the ScanLag methodology. The analysis revealed a bimodal growth rate. Mathematical modeling combined with experimental analysis showed that this bimodality is mediated by a hysteretic memory-switch that results in the stable co-existence of non-virulent and hyper-virulent subpopulations, even after many generations of growth in non-activating conditions. We identified the per operon as the key component of the hysteretic switch. This unique hysteretic memory switch may result in persistent infection and enhanced host-to-host spreading. DOI: http://dx.doi.org/10.7554/eLife.19599.001 PMID:28178445

Feedbacks between climate change and biosphere integrity

NASA Astrophysics Data System (ADS)

Lade, Steven; Anderies, J. Marty; Donges, Jonathan; Steffen, Will; Rockström, Johan; Richardson, Katherine; Cornell, Sarah; Norberg, Jon; Fetzer, Ingo

2017-04-01

The terrestrial and marine biospheres sink substantial fractions of human fossil fuel emissions. How the biosphere's capacity to sink carbon depends on biodiversity and other measures of biosphere integrity is however poorly understood. Here, we (1): review assumptions from literature regarding the relationships between the carbon cycle and the terrestrial and marine biospheres; and (2) explore the consequences of these different assumptions for climate feedbacks using the stylised carbon cycle model PB-INT. We find that: terrestrial biodiversity loss could significantly dampen climate-carbon cycle feedbacks; direct biodiversity effects, if they exist, could rival temperature increases from low-emission trajectories; and the response of the marine biosphere is critical for longer term climate change. Simple, low-dimensional climate models such as PB-INT can help assess the importance of still unknown or controversial earth system processes such as biodiversity loss for climate feedbacks. This study constitutes the first detailed study of the interactions between climate change and biosphere integrity, two of the 'planetary boundaries'.

A mechanism for the activation of the Na/H exchanger NHE-1 by cytoplasmic acidification and mitogens

PubMed Central

Lacroix, Jérôme; Poët, Mallorie; Maehrel, Céline; Counillon, Laurent

2004-01-01

Eukaryotic cells constantly have to fight against internal acidification. In mammals, this task is mainly performed by the ubiquitously expressed electroneutral Na+/H+ exchanger NHE-1, which activates in a cooperative manner when cells become acidic. Despite its biological importance, the mechanism of this activation is still poorly understood, the most commonly accepted hypothesis being the existence of a proton-sensor site on the internal face of the transporter. This work uncovers mutations that lead to a nonallosteric form of the exchanger and demonstrates that NHE-1 activation is best described by a Monod–Wyman–Changeux concerted mechanism for a dimeric transporter. During intracellular acidification, a low-affinity form of NHE-1 is converted into a form possessing a higher affinity for intracellular protons, with no requirement for an additional proton-sensor site on the protein. This new mechanism also explains the activation of the exchanger by growth signals, which shift the equilibrium towards the high-affinity form. PMID:14710192

Bioinspired magnetic reception and multimodal sensing.

PubMed

Taylor, Brian K

2017-08-01

Several animals use Earth's magnetic field in concert with other sensor modes to accomplish navigational tasks ranging from local homing to continental scale migration. However, despite extensive research, animal magnetic reception remains poorly understood. Similarly, the Earth's magnetic field offers a signal that engineered systems can leverage to navigate in environments where man-made positioning systems such as GPS are either unavailable or unreliable. This work uses a behavioral strategy inspired by the migratory behavior of sea turtles to locate a magnetic goal and respond to wind when it is present. Sensing is performed using a number of distributed sensors. Based on existing theoretical biology considerations, data processing is performed using combinations of circles and ellipses to exploit the distributed sensing paradigm. Agent-based simulation results indicate that this approach is capable of using two separate magnetic properties to locate a goal from a variety of initial conditions in both noiseless and noisy sensory environments. The system's ability to locate the goal appears robust to noise at the cost of overall path length.

What makes you tic? Translational approaches to study the role of stress and contextual triggers in Tourette syndrome

PubMed Central

Godar, Sean C; Bortolato, Marco

2016-01-01

Tourette syndrome (TS) is a neurodevelopmental condition characterized by multiple, recurring motor and phonic tics. Rich empirical evidence shows that the severity of tics and associated manifestations is increased by several stressors and contextual triggers; however, the neurobiological mechanisms responsible for symptom exacerbation in TS remain poorly understood. This conceptual gap partially reflects the high phenotypic variability in tics, as well as the existing difficulties in operationalizing and standardizing stress and its effects in a clinical setting. Animal models of TS may be highly informative tools to overcome some of these limitations; these experimental preparations have already provided critical insights on key aspects of TS pathophysiology, and may prove useful to identify the neurochemical alterations induced by different stressful contingencies. In particular, emerging knowledge on the role of contextual triggers in animal models of TS may inform the development of novel pharmacological interventions to reduce tic fluctuations in this disorder. PMID:27939782

Maternal-fetal transfer and metabolism of vitamin A and its precursor β-carotene in the developing tissues.

PubMed

Spiegler, Elizabeth; Kim, Youn-Kyung; Wassef, Lesley; Shete, Varsha; Quadro, Loredana

2012-01-01

The requirement of the developing mammalian embryo for retinoic acid is well established. Retinoic acid, the active form of vitamin A, can be generated from retinol and retinyl ester obtained from food of animal origin, and from carotenoids, mainly β-carotene, from vegetables and fruits. The mammalian embryo relies on retinol, retinyl ester and β-carotene circulating in the maternal bloodstream for its supply of vitamin A. The maternal-fetal transfer of retinoids and carotenoids, as well as the metabolism of these compounds in the developing tissues are still poorly understood. The existing knowledge in this field has been summarized in this review in reference to our basic understanding of the transport and metabolism of retinoids and carotenoids in adult tissues. The need for future research on the metabolism of these essential lipophilic nutrients during development is highlighted. This article is part of a Special Issue entitled: Retinoid and Lipid Metabolism. © 2011 Elsevier B.V. All rights reserved.

Gas chromatography on wall-coated open-tubular columns with ionic liquid stationary phases.

PubMed

Poole, Colin F; Lenca, Nicole

2014-08-29

Ionic liquids have moved from novel to practical stationary phases for gas chromatography with an increasing portfolio of applications. Ionic liquids complement conventional stationary phases because of a combination of thermophysical and solvation properties that only exist for ionic solvents. Their high thermal stability and low vapor pressure makes them suitable as polar stationary phases for separations requiring high temperatures. Ionic liquids are good solvents and can be used to expand the chemical space for separations. They are the only stationary phases with significant hydrogen-bond acidity in common use; they extend the hydrogen-bond basicity of conventional stationary phases; they are as dipolar/polarizable as the most polar conventional stationary phases; and some ionic liquids are significantly less cohesive than conventional polar stationary phases. Problems in column coating techniques and related low column performance, column activity, and stationary phase reactivity require further exploration as the reasons for these features are poorly understood at present. Copyright © 2014 Elsevier B.V. All rights reserved.

Fate mapping of human glioblastoma reveals an invariant stem cell hierarchy.

PubMed

Lan, Xiaoyang; Jörg, David J; Cavalli, Florence M G; Richards, Laura M; Nguyen, Long V; Vanner, Robert J; Guilhamon, Paul; Lee, Lilian; Kushida, Michelle M; Pellacani, Davide; Park, Nicole I; Coutinho, Fiona J; Whetstone, Heather; Selvadurai, Hayden J; Che, Clare; Luu, Betty; Carles, Annaick; Moksa, Michelle; Rastegar, Naghmeh; Head, Renee; Dolma, Sonam; Prinos, Panagiotis; Cusimano, Michael D; Das, Sunit; Bernstein, Mark; Arrowsmith, Cheryl H; Mungall, Andrew J; Moore, Richard A; Ma, Yussanne; Gallo, Marco; Lupien, Mathieu; Pugh, Trevor J; Taylor, Michael D; Hirst, Martin; Eaves, Connie J; Simons, Benjamin D; Dirks, Peter B

2017-09-14

Human glioblastomas harbour a subpopulation of glioblastoma stem cells that drive tumorigenesis. However, the origin of intratumoural functional heterogeneity between glioblastoma cells remains poorly understood. Here we study the clonal evolution of barcoded glioblastoma cells in an unbiased way following serial xenotransplantation to define their individual fate behaviours. Independent of an evolving mutational signature, we show that the growth of glioblastoma clones in vivo is consistent with a remarkably neutral process involving a conserved proliferative hierarchy rooted in glioblastoma stem cells. In this model, slow-cycling stem-like cells give rise to a more rapidly cycling progenitor population with extensive self-maintenance capacity, which in turn generates non-proliferative cells. We also identify rare 'outlier' clones that deviate from these dynamics, and further show that chemotherapy facilitates the expansion of pre-existing drug-resistant glioblastoma stem cells. Finally, we show that functionally distinct glioblastoma stem cells can be separately targeted using epigenetic compounds, suggesting new avenues for glioblastoma-targeted therapy.

Fate mapping of human glioblastoma reveals an invariant stem cell hierarchy

PubMed Central

Lan, Xiaoyang; Jörg, David J.; Cavalli, Florence M. G.; Richards, Laura M.; Nguyen, Long V.; Vanner, Robert J.; Guilhamon, Paul; Lee, Lilian; Kushida, Michelle; Pellacani, Davide; Park, Nicole I.; Coutinho, Fiona J.; Whetstone, Heather; Selvadurai, Hayden J.; Che, Clare; Luu, Betty; Carles, Annaick; Moksa, Michelle; Rastegar, Naghmeh; Head, Renee; Dolma, Sonam; Prinos, Panagiotis; Cusimano, Michael D.; Das, Sunit; Bernstein, Mark; Arrowsmith, Cheryl H.; Mungall, Andrew J.; Moore, Richard A.; Ma, Yussanne; Gallo, Marco; Lupien, Mathieu; Pugh, Trevor J.; Taylor, Michael D.; Hirst, Martin; Eaves, Connie J.; Simons, Benjamin D.; Dirks, Peter B.

2017-01-01

Summary Human glioblastomas (GBMs) harbour a subpopulation of glioblastoma stem cells (GSCs) that drive tumourigenesis. However, the origin of intra-tumoural functional heterogeneity between GBM cells remains poorly understood. Here we study the clonal evolution of barcoded GBM cells in an unbiased way following serial xenotransplantation to define their individual fate behaviours. Independent of an evolving mutational signature, we show that the growth of GBM clones in vivo is consistent with a remarkably neutral process involving a conserved proliferative hierarchy rooted in GSCs. In this model, slow-cycling stem-like cells give rise to a more rapidly cycling progenitor population with extensive self-maintenance capacity, that in turn generates non-proliferative cells. We also identify rare “outlier” clones that deviate from these dynamics, and further show that chemotherapy facilitates the expansion of pre-existing drug-resistant GSCs. Finally, we show that functionally distinct GSCs can be separately targeted using epigenetic compounds, suggesting new avenues for GBM targeted therapy. PMID:28854171

A Catalytic Mechanism for Cysteine N-Terminal Nucleophile Hydrolases, as Revealed by Free Energy Simulations

PubMed Central

Lodola, Alessio; Branduardi, Davide; De Vivo, Marco; Capoferri, Luigi; Mor, Marco; Piomelli, Daniele; Cavalli, Andrea

2012-01-01

The N-terminal nucleophile (Ntn) hydrolases are a superfamily of enzymes specialized in the hydrolytic cleavage of amide bonds. Even though several members of this family are emerging as innovative drug targets for cancer, inflammation, and pain, the processes through which they catalyze amide hydrolysis remains poorly understood. In particular, the catalytic reactions of cysteine Ntn-hydrolases have never been investigated from a mechanistic point of view. In the present study, we used free energy simulations in the quantum mechanics/molecular mechanics framework to determine the reaction mechanism of amide hydrolysis catalyzed by the prototypical cysteine Ntn-hydrolase, conjugated bile acid hydrolase (CBAH). The computational analyses, which were confirmed in water and using different CBAH mutants, revealed the existence of a chair-like transition state, which might be one of the specific features of the catalytic cycle of Ntn-hydrolases. Our results offer new insights on Ntn-mediated hydrolysis and suggest possible strategies for the creation of therapeutically useful inhibitors. PMID:22389698

Understanding the Dynamics of the Oxic-Anoxic Interface in the Black Sea

NASA Astrophysics Data System (ADS)

Stanev, Emil V.; Poulain, Pierre-Marie; Grayek, Sebastian; Johnson, Kenneth S.; Claustre, Hervé; Murray, James W.

2018-01-01

The Black Sea, the largest semienclosed anoxic basin on Earth, can be considered as an excellent natural laboratory for oxic and anoxic biogeochemical processes. The suboxic zone, a thin interface between oxic and anoxic waters, still remains poorly understood because it has been undersampled. This has led to alternative concepts regarding the underlying processes that create it. Existing hypotheses suggest that the interface originates either by isopycnal intrusions that introduce oxygen or the dynamics of manganese redox cycling that are associated with the sinking of particles or chemosynthetic bacteria. Here we reexamine these concepts using high-resolution oxygen, sulfide, nitrate, and particle concentration profiles obtained with sensors deployed on profiling floats. Our results show an extremely stable structure in density space over the entire basin with the exception of areas near the Bosporus plume and in the southern areas dominated by coastal anticyclones. The absence of large-scale horizontal intrusive signatures in the open-sea supports a hypothesis prioritizing the role of biogeochemical processes.

A Pilot Prospective Study of Fetomaternal Hemorrhage Identified by Anemia in Asymptomatic Neonates

PubMed Central

Stroustrup, Annemarie; Plafkin, Callie

2016-01-01

Background Fetomaternal hemorrhage (FMH) is a poorly understood condition in which fetal erythrocytes transfer to the maternal circulation via a faulty placental barrier. Little is known about the true incidence, epidemiology, or pathophysiology of FMH in the general pregnant population as existing studies are based on retrospective cohorts and manifest diagnosis and selection bias. Objective To evaluate the practicability of a prospective study of fetomaternal hemorrhage in the general population based on antepartum maternal blood testing and neonatal anemia. Study Design Prospective cohort study. Result Nineteen pregnant women were enrolled prior to the term delivery of twenty well infants. Five neonates were unexpectedly anemic on first postnatal testing. Antenatal maternal blood samples associated with 2 of 5 anemic newborns had positive Kleihauer-Betke testing while no newborn with a normal postnatal blood count had an associated abnormal Kleihauer-Betke test. Conclusion Clinically significant FMH may be more common than previously thought. Prospective epidemiological study of FMH is feasible. PMID:26765555

A pilot prospective study of fetomaternal hemorrhage identified by anemia in asymptomatic neonates.

PubMed

Stroustrup, A; Plafkin, C

2016-05-01

Fetomaternal hemorrhage (FMH) is a poorly understood condition in which fetal erythrocytes transfer to the maternal circulation via a faulty placental barrier. Little is known about the true incidence, epidemiology or pathophysiology of FMH in the general pregnant population as existing studies are based on retrospective cohorts and manifest diagnosis and selection bias. The objective of this study was to evaluate the practicability of a prospective study of FMH in the general population based on antepartum maternal blood testing and neonatal anemia. Prospective cohort study. Nineteen pregnant women were enrolled prior to the term delivery of 20 well infants. Five neonates were unexpectedly anemic on first postnatal testing. Antenatal maternal blood samples associated with two of the five anemic newborns had positive Kleihauer-Betke testing while no newborn with a normal postnatal blood count had an associated abnormal Kleihauer-Betke test. Clinically significant FMH may be more common than previously thought. Prospective epidemiological study of FMH is feasible.

The microprotein Minion controls cell fusion and muscle formation

PubMed Central

Zhang, Qiao; Vashisht, Ajay A.; O'Rourke, Jason; Corbel, Stéphane Y; Moran, Rita; Romero, Angelica; Miraglia, Loren; Zhang, Jia; Durrant, Eric; Schmedt, Christian; Sampath, Srinath C.; Sampath, Srihari C.

2017-01-01

Although recent evidence has pointed to the existence of small open reading frame (smORF)-encoded microproteins in mammals, their function remains to be determined. Skeletal muscle development requires fusion of mononuclear progenitors to form multinucleated myotubes, a critical but poorly understood process. Here we report the identification of Minion (microprotein inducer of fusion), a smORF encoding an essential skeletal muscle specific microprotein. Myogenic progenitors lacking Minion differentiate normally but fail to form syncytial myotubes, and Minion-deficient mice die perinatally and demonstrate a marked reduction in fused muscle fibres. The fusogenic activity of Minion is conserved in the human orthologue, and co-expression of Minion and the transmembrane protein Myomaker is sufficient to induce cellular fusion accompanied by rapid cytoskeletal rearrangement, even in non-muscle cells. These findings establish Minion as a novel microprotein required for muscle development, and define a two-component programme for the induction of mammalian cell fusion. Moreover, these data also significantly expand the known functions of smORF-encoded microproteins. PMID:28569745

Sudden cardiac death in haemodialysis: clinical epidemiology and mechanisms.

PubMed

Banerjee, Debasish

Sudden cardiac death, which causes premature loss of lives on haemodialysis of the elderly, youths and even children; cannot be prevented, because the aetiology is poorly understood and effective interventions are yet unknown. Improving our knowledge of mechanisms causing sudden cardiac death in haemodialysis patients may help us to design better interventions; and clinical epidemiology of sudden cardiac death could be an important tool to further guide human and animal studies. This review researches the clinical epidemiology of sudden cardiac death to suggest possible mechanisms, although they require further studies. The research shows how traditional cardiovascular risk factors such as age, diabetes and smoking have an impact; non-traditional risk factors such as inflammation, mineral-bone disease and even uraemia itself have higher impact; and how cardiac structural, functional and electrocardiographic markers predict sudden cardiac death in dialysis patients. More in-depth human and animal studies, guided with existing knowledge, are necessary to better understand the mechanisms and design successful interventions. Copyright © 2016 Elsevier Inc. All rights reserved.

A Review of the Role of Food and the Food System in the Transmission and Spread of Ebolavirus

PubMed Central

Mann, Erin; Streng, Stephen; Bergeron, Justin; Kircher, Amy

2015-01-01

The current outbreak of Ebola virus disease (EVD) centered in West Africa is the largest in history, with nearly ten times more individuals contracting the disease than all previous outbreaks combined. The details of human-to-human and zoonotic ebolavirus transmission have justifiably received the largest share of research attention, and much information exists on these topics. However, although food processing—in the form of slaughtering and preparing wildlife for consumption (referred to as bushmeat)—has been implicated in EVD outbreaks, the full role of food in EVD spread is poorly understood and has been little studied. A literature search was undertaken to assess the current state of knowledge regarding how food can or may transmit ebolaviruses and how the food system contributes to EVD outbreak and spread. The literature reveals surprising preliminary evidence that food and the food system may be more implicated in ebolavirus transmission than expected and that further research is urgently needed. PMID:26633305

Homogeneity of Powassan virus populations in naturally infected Ixodes scapularis.

PubMed

Brackney, Doug E; Brown, Ivy K; Nofchissey, Robert A; Fitzpatrick, Kelly A; Ebel, Gregory D

2010-07-05

Powassan virus (POWV, Flaviviridae: Flavivirus) is the sole North American member of the tick-borne encephalitis complex and consists of two distinct lineages that are maintained in ecologically discrete enzootic transmission cycles. The underlying genetic mechanisms that lead to niche partitioning in arboviruses are poorly understood. Therefore, intra- and interhost genetic diversity was analyzed to determine if POWV exists as a quasispecies in nature and quantify selective pressures within and between hosts. In contrast to previous reports for West Nile virus (WNV), significant intrahost genetic diversity was not observed. However, pN (0.238) and d(N)/d(S) ratios (0.092) for interhost diversity were similar to those of WNV. Combined, these data suggest that purifying selection and/or population bottlenecks constrain quasispecies diversity within ticks. These same selective and stochastic mechanisms appear to drive minor sequence changes between ticks. Moreover, Powassan virus populations seem not to be structured as quasispecies in naturally infected adult deer ticks. Copyright 2010 Elsevier Inc. All rights reserved.

HOMOGENEITY OF POWASSAN VIRUS POPULATIONS IN NATURALLY INFECTED IXODES SCAPULARIS

PubMed Central

Brackney, Doug E.; Brown, Ivy K.; Nofchissey, Robert A.; Fitzpatrick, Kelly A.; Ebel, Gregory D.

2010-01-01

Powassan virus (POWV, Flaviviridae: Flavivirus) is the sole North American member of the tick-borne encephalitis complex and consists of two distinct lineages that are maintained in ecologically discrete enzootic transmission cycles. The underlying genetic mechanisms that lead to niche partitioning in arboviruses are poorly understood. Therefore, intra- and interhost genetic diversity was analyzed to determine if POWV exists as a quasispecies in nature and quantify selective pressures within and between hosts. In contrast to previous reports for West Nile virus (WNV), significant intrahost genetic diversity was not observed. However, pN (0.238) and dN/dS ratios (0.092) for interhost diversity were similar to those of WNV. Combined, these data suggest that purifying selection and/or population bottlenecks constrain quasispecies diversity within ticks. These same selective and stochastic mechanisms appear to drive minor sequence changes between ticks. Moreover, Powassan virus populations seem not to be structured as quasispecies in naturally infected adult deer ticks. PMID:20434750

Variability of broad and blueshifted component of [OIII]λ5007 in I ZWI

NASA Astrophysics Data System (ADS)

Wang, J.; Wei, J. Y.; He, X. T.

2005-04-01

Although the existence of asymmetrical profile of [OIII]λ5007 has been discovered for ages, its filiation and physics are poorly understood. Two new spectra of I ZWI taken on November 16, 2001 and on December 3, 2002 were compared with the spectra taken by BG92. Following results are obtained. (1) The certain variations of broad [OIII] during about 10 years separating the observations are identified. The inferred length scale of broad [OIII] emitting region ranges from 0.3 to 3 pc. By assuming a Keplerian motion in line emitting region, the material emitting broad [OIII] is likely to be located at the transient emission line region, between BLR and NLR. (2) We find a positive relation between the FeII emission and flux of Hβ (or continuum). On the other hand, the parameter RFe decreases with ionizing continuum marginally. (3) We detect a low ionized NLR in I ZWI, because of the low flux ratios [OIII]n/Hβn (∼1.7).

Fluorescent sensors reporting the activity of ammonium transceptors in live cells

DOE PAGES

De Michele, Roberto; Ast, Cindy; Loqué, Dominique; ...

2013-07-02

Ammonium serves as key nitrogen source and metabolic intermediate, yet excess causes toxicity. Ammonium uptake is mediated by ammonium transporters, whose regulation is poorly understood. While transport can easily be characterized in heterologous systems, measuring transporter activity in vivo remains challenging. Here we developed a simple assay for monitoring activity in vivo by inserting circularly-permutated GFP into conformation-sensitive positions of two plant and one yeast ammonium transceptors (‘AmTrac’ and ‘MepTrac’). Addition of ammonium to yeast cells expressing the sensors triggered concentration-dependent fluorescence intensity (FI) changes that strictly correlated with the activity of the transporter. Fluorescence-based activity sensors present a novelmore » technology for monitoring the interaction of the transporters with their substrates, the activity of transporters and their regulation in vivo, which is particularly valuable in the context of analytes for which no radiotracers exist, as well as for cell-specific and subcellular transport processes that are otherwise difficult to track.« less

Eighteenth century Yersinia pestis genomes reveal the long-term persistence of an historical plague focus

PubMed Central

Bos, Kirsten I; Herbig, Alexander; Sahl, Jason; Waglechner, Nicholas; Fourment, Mathieu; Forrest, Stephen A; Klunk, Jennifer; Schuenemann, Verena J; Poinar, Debi; Kuch, Melanie; Golding, G Brian; Dutour, Olivier; Keim, Paul; Wagner, David M; Holmes, Edward C; Krause, Johannes; Poinar, Hendrik N

2016-01-01

The 14th–18th century pandemic of Yersinia pestis caused devastating disease outbreaks in Europe for almost 400 years. The reasons for plague’s persistence and abrupt disappearance in Europe are poorly understood, but could have been due to either the presence of now-extinct plague foci in Europe itself, or successive disease introductions from other locations. Here we present five Y. pestis genomes from one of the last European outbreaks of plague, from 1722 in Marseille, France. The lineage identified has not been found in any extant Y. pestis foci sampled to date, and has its ancestry in strains obtained from victims of the 14th century Black Death. These data suggest the existence of a previously uncharacterized historical plague focus that persisted for at least three centuries. We propose that this disease source may have been responsible for the many resurgences of plague in Europe following the Black Death. DOI: http://dx.doi.org/10.7554/eLife.12994.001 PMID:26795402

Groundwater connectivity of upland-embedded wetlands in the Prairie Pothole Region

USGS Publications Warehouse

Neff, Brian; Rosenberry, Donald O.

2018-01-01

Groundwater connections from upland-embedded wetlands to downstream waterbodies remain poorly understood. In principle, water from upland-embedded wetlands situated high in a landscape should flow via groundwater to waterbodies situated lower in the landscape. However, the degree of groundwater connectivity varies across systems due to factors such as geologic setting, hydrologic conditions, and topography. We use numerical models to evaluate the conditions suitable for groundwater connectivity between upland-embedded wetlands and downstream waterbodies in the prairie pothole region of North Dakota (USA). Results show groundwater connectivity between upland-embedded wetlands and other waterbodies is restricted when these wetlands are surrounded by a mounding water table. However, connectivity exists among adjacent upland-embedded wetlands where water–table mounds do not form. In addition, the presence of sand layers greatly facilitates groundwater connectivity of upland-embedded wetlands. Anisotropy can facilitate connectivity via groundwater flow, but only if it becomes unrealistically large. These findings help consolidate previously divergent views on the significance of local and regional groundwater flow in the prairie pothole region.

Dip in the gene pool: metagenomic survey of natural coccolithovirus communities.

PubMed

Pagarete, António; Kusonmano, Kanthida; Petersen, Kjell; Kimmance, Susan A; Martínez Martínez, Joaquín; Wilson, William H; Hehemann, Jan-Hendrik; Allen, Michael J; Sandaa, Ruth-Anne

2014-10-01

Despite the global oceanic distribution and recognised biogeochemical impact of coccolithoviruses (EhV), their diversity remains poorly understood. Here we employed a metagenomic approach to study the occurrence and progression of natural EhV community genomic variability. Analysis of EhV metagenomes from the early and late stages of an induced bloom led to three main discoveries. First, we observed resilient and specific genomic signatures in the EhV community associated with the Norwegian coast, which reinforce the existence of limitations to the capacity of dispersal and genomic exchange among EhV populations. Second, we identified a hyper-variable region (approximately 21kbp long) in the coccolithovirus genome. Third, we observed a clear trend for EhV relative amino-acid diversity to reduce from early to late stages of the bloom. This study validated two new methodological combinations, and proved very useful in the discovery of new genomic features associated with coccolithovirus natural communities. Copyright © 2014 Elsevier Inc. All rights reserved.

Flocking Transition in Confluent Tissues

NASA Astrophysics Data System (ADS)

Paoluzzi, Matteo; Giavazzi, Fabio; Macchi, Marta; Scita, Giorgio; Cerbino, Roberto; Manning, Lisa; Marchetti, Cristina

The emerging of collective migration in biological tissues plays a pivotal role in embryonic morphogenesis, wound healing and cancer invasion. While many aspects of single cell movements are well established, the mechanisms leading to coherent displacements of cohesive cell groups are still poorly understood. Some of us recently proposed a Self-Propelled Voronoi (SPV) model of dense tissues that combines self-propelled particle models and vertex models of confluent cell layers and exhibits a liquid-solid transition as a function of cell shape and cell motility. We now examine the role of cell polarization on collective cell dynamics by introducing an orientation mechanism that aligns cell polarization with local cell motility. The model predicts a density-independent flocking transition tuned by the strength of the aligning interaction, with both solid and liquid flocking states existing in different regions of parameter space. MP and MCM were supported by the Simons Foundation Targeted Grant in the Mathematical Modeling of Living Systems Number: 342354 and by the Syracuse Soft Matter Program.

Conformational switching of the pseudokinase domain promotes human MLKL tetramerization and cell death by necroptosis.

PubMed

Petrie, Emma J; Sandow, Jarrod J; Jacobsen, Annette V; Smith, Brian J; Griffin, Michael D W; Lucet, Isabelle S; Dai, Weiwen; Young, Samuel N; Tanzer, Maria C; Wardak, Ahmad; Liang, Lung-Yu; Cowan, Angus D; Hildebrand, Joanne M; Kersten, Wilhelmus J A; Lessene, Guillaume; Silke, John; Czabotar, Peter E; Webb, Andrew I; Murphy, James M

2018-06-21

Necroptotic cell death is mediated by the most terminal known effector of the pathway, MLKL. Precisely how phosphorylation of the MLKL pseudokinase domain activation loop by the upstream kinase, RIPK3, induces unmasking of the N-terminal executioner four-helix bundle (4HB) domain of MLKL, higher-order assemblies, and permeabilization of plasma membranes remains poorly understood. Here, we reveal the existence of a basal monomeric MLKL conformer present in human cells prior to exposure to a necroptotic stimulus. Following activation, toggling within the MLKL pseudokinase domain promotes 4HB domain disengagement from the pseudokinase domain αC helix and pseudocatalytic loop, to enable formation of a necroptosis-inducing tetramer. In contrast to mouse MLKL, substitution of RIPK3 substrate sites in the human MLKL pseudokinase domain completely abrogated necroptotic signaling. Therefore, while the pseudokinase domains of mouse and human MLKL function as molecular switches to control MLKL activation, the underlying mechanism differs between species.

Summer rainfall over the southwestern Tibetan Plateau controlled by deep convection over the Indian subcontinent

PubMed Central

Dong, Wenhao; Lin, Yanluan; Wright, Jonathon S.; Ming, Yi; Xie, Yuanyu; Wang, Bin; Luo, Yong; Huang, Wenyu; Huang, Jianbin; Wang, Lei; Tian, Lide; Peng, Yiran; Xu, Fanghua

2016-01-01

Despite the importance of precipitation and moisture transport over the Tibetan Plateau for glacier mass balance, river runoff and local ecology, changes in these quantities remain highly uncertain and poorly understood. Here we use observational data and model simulations to explore the close relationship between summer rainfall variability over the southwestern Tibetan Plateau (SWTP) and that over central-eastern India (CEI), which exists despite the separation of these two regions by the Himalayas. We show that this relationship is maintained primarily by ‘up-and-over' moisture transport, in which hydrometeors and moisture are lifted by convective storms over CEI and the Himalayan foothills and then swept over the SWTP by the mid-tropospheric circulation, rather than by upslope flow over the Himalayas. Sensitivity simulations confirm the importance of up-and-over transport at event scales, and an objective storm classification indicates that this pathway accounts for approximately half of total summer rainfall over the SWTP. PMID:26948491

Autonomous Onboard Science Data Analysis for Comet Missions

NASA Technical Reports Server (NTRS)

Thompson, David R.; Tran, Daniel Q.; McLaren, David; Chien, Steve A.; Bergman, Larry; Castano, Rebecca; Doyle, Richard; Estlin, Tara; Lenda, Matthew

2012-01-01

Coming years will bring several comet rendezvous missions. The Rosetta spacecraft arrives at Comet 67P/Churyumov-Gerasimenko in 2014. Subsequent rendezvous might include a mission such as the proposed Comet Hopper with multiple surface landings, as well as Comet Nucleus Sample Return (CNSR) and Coma Rendezvous and Sample Return (CRSR). These encounters will begin to shed light on a population that, despite several previous flybys, remains mysterious and poorly understood. Scientists still have little direct knowledge of interactions between the nucleus and coma, their variation across different comets or their evolution over time. Activity may change on short timescales so it is challenging to characterize with scripted data acquisition. Here we investigate automatic onboard image analysis that could act faster than round-trip light time to capture unexpected outbursts and plume activity. We describe one edge-based method for detect comet nuclei and plumes, and test the approach on an existing catalog of comet images. Finally, we quantify benefits to specific measurement objectives by simulating a basic plume monitoring campaign.

Thirty-day mortality rate in women with cancer and venous thromboembolism. Findings from the RIETE Registry.

PubMed

Trujillo-Santos, Javier; Casas, José Manuel; Casa, José Manuel; Casado, Ignacio; Samperiz, Angel Luis; Quintavalla, Roberto; Sahuquillo, Joan Carles; Monreal, Manuel

2011-02-01

The influence of the site of cancer on outcome in cancer women with venous thromboembolism (VTE) is poorly understood. Reliable information on its influence might facilitate better use of prevention strategies. We assessed the 30-day outcome in all women with active cancer in the RIETE Registry, trying to identify if differences exist according to the tumor site. Up to May 2010, 2474 women with cancer and acute VTE had been enrolled. The most common sites were the breast (26%), colon (13%), uterus (9.3%), and haematologic (8.6%) cancers. During the 30-day study period, 329 (13%) patients died. Of them, 71 (2.9%) died of pulmonary embolism (PE), 22 (0.9%) died of bleeding. Fatal PE was more common in women with breast, colorectal, lung or pancreatic cancer (59% of the fatal PEs). Fatal bleeding was more frequent in women with colorectal, haematologic, ovarian cancer or carcinoma of unknown origin (55% of fatal bleedings). © 2011 Elsevier Ltd. All rights reserved.

PslG, a self-produced glycosyl hydrolase, triggers biofilm disassembly by disrupting exopolysaccharide matrix.

PubMed

Yu, Shan; Su, Tiantian; Wu, Huijun; Liu, Shiheng; Wang, Di; Zhao, Tianhu; Jin, Zengjun; Du, Wenbin; Zhu, Mei-Jun; Chua, Song Lin; Yang, Liang; Zhu, Deyu; Gu, Lichuan; Ma, Luyan Z

2015-12-01

Biofilms are surface-associated communities of microorganism embedded in extracellular matrix. Exopolysaccharide is a critical component in the extracellular matrix that maintains biofilm architecture and protects resident biofilm bacteria from antimicrobials and host immune attack. However, self-produced factors that target the matrix exopolysaccharides, are still poorly understood. Here, we show that PslG, a protein involved in the synthesis of a key biofilm matrix exopolysaccharide Psl in Pseudomonas aeruginosa, prevents biofilm formation and disassembles existing biofilms within minutes at nanomolar concentrations when supplied exogenously. The crystal structure of PslG indicates the typical features of an endoglycosidase. PslG mainly disrupts the Psl matrix to disperse bacteria from biofilms. PslG treatment markedly enhances biofilm sensitivity to antibiotics and macrophage cells, resulting in improved biofilm clearance in a mouse implant infection model. Furthermore, PslG shows biofilm inhibition and disassembly activity against a wide range of Pseudomonas species, indicating its great potential in combating biofilm-related complications.

Relationship between insulin sensitivity index and cognitive function in diet-induced insulin resistant rats.

PubMed

Chen, Sisi; Xie, Hao; Wu, Jing; Hong, Hao; Jin, Jianwen; Fang, Jinbo; Huang, Ji; Fu, Ying Zhou; Ji, Hui; Li, Yong Qi; Long, Yan; Xia, Yuan Zheng

2009-06-01

Clinical and animal studies have revealed significant cognitive impairment in type II diabetic subjects. However, whether there is a relationship between insulin resistance and cognitive function is poorly understood. In the present study, we used a high fat diet to induce insulin resistance (IR) in rats, insulin sensitivity index (ISI) (= FINS x FPG/22.5) to assess the extent of insulin resistance and the Morris Water Maze Task to judge cognitive function. The relationship between insulin sensitivity index and cognitive function was determined by analysing the correlation between ISI and the time rat spent in targeted quadrant, as well as between ISI and the times the rat swam across the very point where a platform was previously placed, using Pearson's method. Perfect negative correlation between ISI and cognitive function existed when ISI fell within a certain range, which indicates that insulin resistance is associated with cognitive function impairment in some cases where ISI might be an indicator.

Cocaine Abuse, Traumatic Brain Injury, and Preexisting Brain Lesions as Risk Factors for Bupropion-Associated Psychosis.

PubMed

Barman, Rajdip; Kumar, Sanjeev; Pagadala, Bhuvaneshwar; Detweiler, Mark B

2017-08-01

Bupropion is generally considered safe and is widely used both as a monotherapy and as an augmentation agent for the treatment of major depression. Concerns have been raised about bupropion's propensity to precipitate new psychosis and worsen existing psychotic symptoms, although the mechanism is poorly understood. Three cases are reported in which bupropion use was associated with psychosis. The aim of the study was to explore the risk factors and possible mechanisms of psychosis in each case. Case 1 describes the interaction of cocaine abuse sensitization in a patient who developed psychosis with a lower dosage of bupropion. Cases 2 and 3 discuss the role of traumatic brain injury and structural brain lesions in increasing the risk of psychosis when using bupropion. Cocaine abuse, traumatic brain injury, and preexisting brain lesions appear to be risk factors for developing psychosis in persons taking bupropion. In such cases, clinicians should carefully assess the risks and benefits and closely monitor patients for symptoms of psychosis.

Cell identity regulators link development and stress responses in the Arabidopsis root.

PubMed

Iyer-Pascuzzi, Anjali S; Jackson, Terry; Cui, Hongchang; Petricka, Jalean J; Busch, Wolfgang; Tsukagoshi, Hironaka; Benfey, Philip N

2011-10-18

Stress responses in plants are tightly coordinated with developmental processes, but interaction of these pathways is poorly understood. We used genome-wide assays at high spatiotemporal resolution to understand the processes that link development and stress in the Arabidopsis root. Our meta-analysis finds little evidence for a universal stress response. However, common stress responses appear to exist with many showing cell type specificity. Common stress responses may be mediated by cell identity regulators because mutations in these genes resulted in altered responses to stress. Evidence for a direct role for cell identity regulators came from genome-wide binding profiling of the key regulator SCARECROW, which showed binding to regulatory regions of stress-responsive genes. Coexpression in response to stress was used to identify genes involved in specific developmental processes. These results reveal surprising linkages between stress and development at cellular resolution, and show the power of multiple genome-wide data sets to elucidate biological processes. Copyright © 2011 Elsevier Inc. All rights reserved.

Sea-ice floe-size distribution in the context of spontaneous scaling emergence in stochastic systems.

PubMed

Herman, Agnieszka

2010-06-01

Sea-ice floe-size distribution (FSD) in ice-pack covered seas influences many aspects of ocean-atmosphere interactions. However, data concerning FSD in the polar oceans are still sparse and processes shaping the observed FSD properties are poorly understood. Typically, power-law FSDs are assumed although no feasible explanation has been provided neither for this one nor for other properties of the observed distributions. Consequently, no model exists capable of predicting FSD parameters in any particular situation. Here I show that the observed FSDs can be well represented by a truncated Pareto distribution P(x)=x(-1-α) exp[(1-α)/x] , which is an emergent property of a certain group of multiplicative stochastic systems, described by the generalized Lotka-Volterra (GLV) equation. Building upon this recognition, a possibility of developing a simple agent-based GLV-type sea-ice model is considered. Contrary to simple power-law FSDs, GLV gives consistent estimates of the total floe perimeter, as well as floe-area distribution in agreement with observations.

Sea-ice floe-size distribution in the context of spontaneous scaling emergence in stochastic systems

NASA Astrophysics Data System (ADS)

Herman, Agnieszka

2010-06-01

Sea-ice floe-size distribution (FSD) in ice-pack covered seas influences many aspects of ocean-atmosphere interactions. However, data concerning FSD in the polar oceans are still sparse and processes shaping the observed FSD properties are poorly understood. Typically, power-law FSDs are assumed although no feasible explanation has been provided neither for this one nor for other properties of the observed distributions. Consequently, no model exists capable of predicting FSD parameters in any particular situation. Here I show that the observed FSDs can be well represented by a truncated Pareto distribution P(x)=x-1-αexp[(1-α)/x] , which is an emergent property of a certain group of multiplicative stochastic systems, described by the generalized Lotka-Volterra (GLV) equation. Building upon this recognition, a possibility of developing a simple agent-based GLV-type sea-ice model is considered. Contrary to simple power-law FSDs, GLV gives consistent estimates of the total floe perimeter, as well as floe-area distribution in agreement with observations.

ANATOMY OF A SOLAR FLARE: MEASUREMENTS OF THE 2006 DECEMBER 14 X-CLASS FLARE WITH GONG, HINODE, AND RHESSI

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

Matthews, S. A.; Zharkov, S.; Zharkova, V. V.

2011-10-01

Some of the most challenging observations to explain in the context of existing flare models are those related to the lower atmosphere and below the solar surface. Such observations, including changes in the photospheric magnetic field and seismic emission, indicate the poorly understood connections between energy release in the corona and its impact in the photosphere and the solar interior. Using data from Hinode, TRACE, RHESSI, and GONG we study the temporal and spatial evolution of the 2006 December 14 X-class flare in the chromosphere, photosphere, and the solar interior. We investigate the connections between the emission at various atmosphericmore » depths, including acoustic signatures obtained by time-distance and holography methods from the GONG data. We report the horizontal displacements observed in the photosphere linked to the timing and locations of the acoustic signatures we believe to be associated with this flare, their vertical and horizontal displacement velocities, and their potential implications for current models of flare dynamics.« less

Diversity of sharp-wave-ripple LFP signatures reveals differentiated brain-wide dynamical events.

PubMed

Ramirez-Villegas, Juan F; Logothetis, Nikos K; Besserve, Michel

2015-11-17

Sharp-wave-ripple (SPW-R) complexes are believed to mediate memory reactivation, transfer, and consolidation. However, their underlying neuronal dynamics at multiple scales remains poorly understood. Using concurrent hippocampal local field potential (LFP) recordings and functional MRI (fMRI), we study local changes in neuronal activity during SPW-R episodes and their brain-wide correlates. Analysis of the temporal alignment between SPW and ripple components reveals well-differentiated SPW-R subtypes in the CA1 LFP. SPW-R-triggered fMRI maps show that ripples aligned to the positive peak of their SPWs have enhanced neocortical metabolic up-regulation. In contrast, ripples occurring at the trough of their SPWs relate to weaker neocortical up-regulation and absent subcortical down-regulation, indicating differentiated involvement of neuromodulatory pathways in the ripple phenomenon mediated by long-range interactions. To our knowledge, this study provides the first evidence for the existence of SPW-R subtypes with differentiated CA1 activity and metabolic correlates in related brain areas, possibly serving different memory functions.

Diversity of sharp-wave–ripple LFP signatures reveals differentiated brain-wide dynamical events

PubMed Central

Ramirez-Villegas, Juan F.; Logothetis, Nikos K.; Besserve, Michel

2015-01-01

Sharp-wave–ripple (SPW-R) complexes are believed to mediate memory reactivation, transfer, and consolidation. However, their underlying neuronal dynamics at multiple scales remains poorly understood. Using concurrent hippocampal local field potential (LFP) recordings and functional MRI (fMRI), we study local changes in neuronal activity during SPW-R episodes and their brain-wide correlates. Analysis of the temporal alignment between SPW and ripple components reveals well-differentiated SPW-R subtypes in the CA1 LFP. SPW-R–triggered fMRI maps show that ripples aligned to the positive peak of their SPWs have enhanced neocortical metabolic up-regulation. In contrast, ripples occurring at the trough of their SPWs relate to weaker neocortical up-regulation and absent subcortical down-regulation, indicating differentiated involvement of neuromodulatory pathways in the ripple phenomenon mediated by long-range interactions. To our knowledge, this study provides the first evidence for the existence of SPW-R subtypes with differentiated CA1 activity and metabolic correlates in related brain areas, possibly serving different memory functions. PMID:26540729

Inflammation and wound healing: The role of the macrophage

PubMed Central

Koh, Timothy J.; DiPietro, Luisa Ann

2013-01-01

The macrophage is a prominent inflammatory cell in wounds, but its role in healing remains incompletely understood. Macrophages have been described to have many functions in wounds, including host defense, the promotion and resolution of inflammation, the removal of apoptotic cells, and the support of cell proliferation and tissue restoration following injury. Recent studies suggest that macrophages exist in several different phenotypic states within the healing wound, and that the influence of these cells on each stage of repair varies with the specific phenotypes. While the macrophage is beneficial to the repair of normally healing wounds, this pleotropic cell type may promote excessive inflammation and/or fibrosis in certain circumstances. Emerging evidence suggests that macrophage dysfunction is a component of the pathogenesis of non-healing and poorly healing wounds. Due to advances in the understanding of this multi-functional cell, the macrophage continues to be an attractive therapeutic target both to reduce fibrosis and scarring, and to improve healing of chronic wounds. PMID:21740602

Comparative proteomics analysis of Spodoptera frugiperda cells during Autographa californica multiple nucleopolyhedrovirus infection.

PubMed

Yu, Qian; Xiong, Youhua; Gao, Hang; Liu, Jianliang; Chen, Zhiqiang; Wang, Qin; Wen, Dongling

2015-08-04

Increasing evidence sugggest that in addition of balculovirus controling insect host, host cells also responds to balculovirus infection. However, compared to existing knowledge on virus gene, host cell responses are relatively poorly understood. In this study, Spodoptera frugiperda (Sf9) cells were infected with Autographa californica multiple nucleopolyhedrovirus (AcMNPV). The protein composition and protein changes of Spodoptera frugiperda (Sf9) cells of different infection stages were analysed by isobaric tag for relative and absolute quantification (iTRAQ) techniques. A total of 4004 Sf9 proteins were identified by iTRAQ and 413 proteins were found as more than 1.5-fold changes in abundance. The 413 proteins were categorised according to GO classification for insects and were categorised into: biological process, molecular function and cellular component. The determination of the protein changes in infected Sf9 cells would help to better understanding of host cell responses and facilitate better design of this virus-host cell interaction in pest insect control and other related fields.

Modeling the Free Carrier Recombination Kinetics in PTB7:PCBM Organic Photovoltaics

DOE PAGES

Oosterhout, Stefan D.; Ferguson, Andrew J.; Larson, Bryon W.; ...

2016-10-03

Currently the exact recombination mechanism of free carriers in organic photovoltaic (OPV) devices is poorly understood. Often a reduced Langevin model is used to describe the decay behavior of electrons and holes. Here we propose a novel, simple kinetic model that accurately describes the decay behavior of free carriers in the PTB7:PCBM organic photovoltaic blend. In order to accurately describe the recombination behavior of free carriers as measured by time-resolved microwave conductivity (TRMC), this model needs to only take into account free and trapped holes in the polymer, and free electrons in the fullerene. The model is consistent for differentmore » PTB7:PCBM blend ratios and spans a light intensity range of over 3 orders of magnitude. Furthermore, the model demonstrates that dark carriers exist in the polymer and interact with photoinduced charge carriers, and that the trapping and detrapping rates of the holes are of high importance to the overall carrier lifetime.« less

Taxonomic revision and phylogenetic position of Osteocephalus festae (Anura, Hylidae) with description of its larva

PubMed Central

Ron, Santiago R.; Toral, Eduardo; Venegas, Pablo J.; Barnes, Charles W.

2010-01-01

Abstract Osteocephalus festae is an Amazonian species recently resurrected from a synonymy with Osteocephalus buckleyi. Because few specimens are known, its morphological variation, diagnostic characters, and distribution are poorly understood. Herein we determine its phylogenetic relationships and provide a complete taxonomic account based on recently collected specimens (adults and larvae) from nine localities in Ecuador and Peru. Osteocephalus festae is most similar to Osteocephalus verruciger from which it differs in having less tuberculate dorsal skin on males, smaller tympanum, and more tooth rows in the oral disk of larvae. A phylogeny based on mitochondrial DNA sequences, genes 12S and ND1, shows that Osteocephalus festae is closely related to Osteocephalus buckleyi, Osteocephalus mutabor and Osteocephalus verruciger. A clade consisting of Osteocephalus festae, Osteocephalus verruciger, and Osteocephalus buckleyi is characterized by stream dwelling tadpoles. Surprisingly, we found paraphyly among Ecuadorian populations of Osteocephalus buckleyi and Osteocephalus verruciger. The causes for paraphyly are unknown but in Osteocephalus buckleyi may result from the existence of cryptic species. PMID:21594044

Can physical exercise in old age improve memory and hippocampal function?

PubMed Central

van Praag, Henriette; Sendtner, Michael

2016-01-01

Abstract Physical exercise can convey a protective effect against cognitive decline in ageing and Alzheimer’s disease. While the long-term health-promoting and protective effects of exercise are encouraging, it’s potential to induce neuronal and vascular plasticity in the ageing brain is still poorly understood. It remains unclear whether exercise slows the trajectory of normal ageing by modifying vascular and metabolic risk factors and/or consistently boosts brain function by inducing structural and neurochemical changes in the hippocampus and related medial temporal lobe circuitry—brain areas that are important for learning and memory. Hence, it remains to be established to what extent exercise interventions in old age can improve brain plasticity above and beyond preservation of function. Existing data suggest that exercise trials aiming for improvement and preservation may require different outcome measures and that the balance between the two may depend on exercise intensity and duration, the presence of preclinical Alzheimer’s disease pathology, vascular and metabolic risk factors and genetic variability. PMID:26912638

Developmental lineage priming in Dictyostelium by heterogeneous Ras activation.

PubMed

Chattwood, Alex; Nagayama, Koki; Bolourani, Parvin; Harkin, Lauren; Kamjoo, Marzieh; Weeks, Gerald; Thompson, Christopher R L

2013-11-26

In cell culture, genetically identical cells often exhibit heterogeneous behavior, with only 'lineage primed' cells responding to differentiation inducing signals. It has recently been proposed that such heterogeneity exists during normal embryonic development to allow position independent patterning based on 'salt and pepper' differentiation and sorting out. However, the molecular basis of lineage priming and how it leads to reproducible cell type proportioning are poorly understood. To address this, we employed a novel forward genetic approach in the model organism Dictyostelium discoideum. These studies reveal that the Ras-GTPase regulator gefE is required for normal lineage priming and salt and pepper differentiation. This is because Ras-GTPase activity sets the intrinsic response threshold to lineage specific differentiation signals. Importantly, we show that although gefE expression is uniform, transcription of its target, rasD, is both heterogeneous and dynamic, thus providing a novel mechanism for heterogeneity generation and position-independent differentiation. DOI: http://dx.doi.org/10.7554/eLife.01067.001.

Mineral potential for incompatible element deposits hosted in pegmatites, alkaline rocks, and carbonatites in the Islamic Republic of Mauritania (phase V, deliverable 87): Chapter Q in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)

USGS Publications Warehouse

Taylor, Cliff D.; Giles, Stuart A.

2015-01-01

USGS review of PRISM-I data suggests that there is abundant documentation of the Bou Naga alkaline complex and to a lesser degree, the Guelb er Richat carbonatite complex, but that all other occurrences of U, Th, REE, and associated elements are poorly described, and poorly understood (Taylor, 2007)

Atherosclerosis associated with pericardial effusion in a central bearded dragon (Pogona vitticeps).

PubMed

Schilliger, Lionel; Lemberger, Karin; Chai, Norin; Bourgeois, Aude; Charpentier, Maud

2010-09-01

Atherosclerosis is a common disease in pet birds, particularly in psittacines, and is frequently found when performing postmortem examinations on adult and old dogs, in which it is mainly associated with endocrine diseases, such as hypothyroidism and diabetes mellitus. However, atherosclerosis is poorly documented in reptiles and consequently poorly understood. In the current case report, atherosclerosis and pericardial effusion were diagnosed in a 2-year-old male central bearded dragon (Pogona vitticeps) based on ultrasound visualization, necropsy, and histologic examination.

Access to pain treatment as a human right.

PubMed

Lohman, Diederik; Schleifer, Rebecca; Amon, Joseph J

2010-01-20

Almost five decades ago, governments around the world adopted the 1961 Single Convention on Narcotic Drugs which, in addition to addressing the control of illicit narcotics, obligated countries to work towards universal access to the narcotic drugs necessary to alleviate pain and suffering. Yet, despite the existence of inexpensive and effective pain relief medicines, tens of millions of people around the world continue to suffer from moderate to severe pain each year without treatment. Significant barriers to effective pain treatment include: the failure of many governments to put in place functioning drug supply systems; the failure to enact policies on pain treatment and palliative care; poor training of healthcare workers; the existence of unnecessarily restrictive drug control regulations and practices; fear among healthcare workers of legal sanctions for legitimate medical practice; and the inflated cost of pain treatment. These barriers can be understood not only as a failure to provide essential medicines and relieve suffering but also as human rights abuses. According to international human rights law, countries have to provide pain treatment medications as part of their core obligations under the right to health; failure to take reasonable steps to ensure that people who suffer pain have access to adequate pain treatment may result in the violation of the obligation to protect against cruel, inhuman and degrading treatment.

Controllable Growth and Formation Mechanisms of Dislocated WS2 Spirals.

PubMed

Fan, Xiaopeng; Zhao, Yuzhou; Zheng, Weihao; Li, Honglai; Wu, Xueping; Hu, Xuelu; Zhang, Xuehong; Zhu, Xiaoli; Zhang, Qinglin; Wang, Xiao; Yang, Bin; Chen, Jianghua; Jin, Song; Pan, Anlian

2018-06-13

Two-dimensional (2D) layered metal dichalcogenides can form spiral nanostructures by a screw-dislocation-driven mechanism, which leads to changes in crystal symmetry and layer stackings that introduce attractive physical properties different from their bulk and few-layer nanostructures. However, controllable growth of spirals is challenging and their growth mechanisms are poorly understood. Here, we report the controllable growth of WS 2 spiral nanoplates with different stackings by a vapor phase deposition route and investigate their formation mechanisms by combining atomic force microscopy with second harmonic generation imaging. Previously not observed "spiral arm" features could be explained as covered dislocation spiral steps, and the number of spiral arms correlates with the number of screw dislocations initiated at the bottom plane. The supersaturation-dependent growth can generate new screw dislocations from the existing layers, or even new layers templated by existing screw dislocations. Different number of dislocations and orientation of new layers result in distinct morphologies, different layer stackings, and more complex nanostructures, such as triangular spiral nanoplates with hexagonal spiral pattern on top. This work provides the understanding and control of dislocation-driven growth of 2D nanostructures. These spiral nanostructures offer diverse candidates for probing the physical properties of layered materials and exploring new applications in functional nanoelectronic and optoelectronic devices.

Scale criticality in estimating ecosystem carbon dynamics

USGS Publications Warehouse

Zhao, Shuqing; Liu, Shuguang

2014-01-01

Scaling is central to ecology and Earth system sciences. However, the importance of scale (i.e. resolution and extent) for understanding carbon dynamics across scales is poorly understood and quantified. We simulated carbon dynamics under a wide range of combinations of resolution (nine spatial resolutions of 250 m, 500 m, 1 km, 2 km, 5 km, 10 km, 20 km, 50 km, and 100 km) and extent (57 geospatial extents ranging from 108 to 1 247 034 km2) in the southeastern United States to explore the existence of scale dependence of the simulated regional carbon balance. Results clearly show the existence of a critical threshold resolution for estimating carbon sequestration within a given extent and an error limit. Furthermore, an invariant power law scaling relationship was found between the critical resolution and the spatial extent as the critical resolution is proportional to An (n is a constant, and A is the extent). Scale criticality and the power law relationship might be driven by the power law probability distributions of land surface and ecological quantities including disturbances at landscape to regional scales. The current overwhelming practices without considering scale criticality might have largely contributed to difficulties in balancing carbon budgets at regional and global scales.

USING MOLECULAR PROBES TO STUDY INTERFACIAL REDOX REACTION AT FE-BEARING SMECTITES

EPA Science Inventory

The interfacial electron transfer of clay-water systems has a wide range of significance in geochemical and biogeochernical environments. However the mechanism of interfacial electron transport is poorly understood. The electron transfer mechanism at the solid-water interfaces of...

Larval fish distribution in the St. Louis River estuary

EPA Science Inventory

Our objective was to determine what study design, environmental, and habitat variables contribute to the distribution and abundance of larval fish in the St. Louis River estuary. Larval fish habitat associations are poorly understood in Great Lakes coastal wetlands, yet critical ...

Post-traumatic unilateral plantar hyperhidrosis.

PubMed

Eren, Y; Yavasoglu, N G; Comoglu, S S

2016-02-01

Localized unilateral hyperhidrosis is rare and poorly understood, sometimes stemming from trauma. Feet, quite vulnerable to trauma are affected by disease-mediated plantar hyperhidrosis, usually bilaterally. This report describes partial hyperhidrosis developing post-traumatically on the left plantar region of a 52-year-old male.

Predator-prey interaction reveals local effects of high-altitude insect migration

USDA-ARS?s Scientific Manuscript database

High-altitude nocturnal insect migrations represent significant pulses of resources, yet are difficult to study and poorly understood. Predator-prey interactions, specifically migratory moth consumption by high-flying bats, potentially reveal flows of migratory insects across a landscape. In North...

Assessing Effects of Pesticides on the Bee Immune System

EPA Science Inventory

Populations of some managed and wild pollinators are in decline as a result of multiple interacting factors including parasites, disease, poor nutrition and pesticides. The role that diminished immunity plays in these declines is not understood. The U.S. Environmental Protection ...

DISSECTING COLONY DEVELOPMENT OF NEUROSPORA CRASSA USING mRNA PROFILING AND COMPARTATIVE GENOMICS APPROACHES

USDA-ARS?s Scientific Manuscript database

Colony development, which includes hyphal extension, branching, anastomosis and asexual sporulation are fundamental aspects of the lifecycle of filamentous fungi; genetic mechanisms underlying these phenomena are poorly understood. We conducted transcriptional profiling during colony development of...

USEPA RESEARCH ON FISH - HABITAT RELATIONSHIPS IN GREAT LAKES COASTAL MARSHES

EPA Science Inventory

Despite numerous studies documenting fish use of particular habitat elements, the role of habitat mosaics in supporting wetland fishes is poorly understood. USEPA's Mid-Continent Ecology Division has initiated research to identify relationships of fish and habitat in coastal mars...

A Cellular Game of Telephone: Trans Tissue Reprogramming of Responses to Toxic Stimuli

EPA Science Inventory

Exposure to air pollution is a leading cause of cardiopulmonary morbidity and mortality; however, while these effects outside the lung have been associated with aberrant oxidative stress and inflammation, the underlying molecular mechanisms are poorly understood. We hypothesized ...

Cellular Plasticity in the Diabetic Myocardium

DTIC Science & Technology

2017-09-01

demonstrated that obese diabetic db/db mice in a C57Bl6J background exhibit cardiac remodeling, associated with modest ventricular dilation...HFpEF, the cellular basis for fibrotic remodeling of the ventricle is poorly understood. Metabolic diseases (such as obesity and diabetes) are

Reduce Confusion about Diffusion.

ERIC Educational Resources Information Center

Hebrank, Mary R.

1997-01-01

Presents activities that allow students to explore the fundamental but poorly understood concept of diffusion by appealing to their kinesthetic senses first, then challenging their analytical skills as they try to deduce the mathematical principle involved. Presents a computer simulation of diffusion and discusses diffusion's limitations and…

INTERNATIONAL CHILDHOOD CANCER COHORT CONSORTIUM (Journal Article)

EPA Science Inventory

Childhood cancers are rare conditions whose etiology is poorly understood. There is evidence that for some, the causal pathway may commence in utero or during peri-conception. One traditional epidemiologic approach to the study of rare diseases is the use of a retrospective cas...

A Multilevel Investigation of Neighborhood Effects on Parental Warmth

ERIC Educational Resources Information Center

Tendulkar, Shalini A.; Buka, Stephen; Dunn, Erin C.; Subramanian, S. V.; Koenen, Karestan C.

2010-01-01

Although researchers recognize that social contexts shape parenting behaviors, the relationship between neighborhood environment and parenting remains poorly understood. To address this gap, we investigated the associations between compositional and contextual (structural, social, and safety) characteristics of neighborhoods and parental warmth.…

Origins of Brain Tumor Macrophages.

PubMed

De Palma, Michele

2016-12-12

The ontogeny of brain-tumor-associated macrophages is poorly understood. New findings indicate that both resident microglia and blood-derived monocytes generate the pool of macrophages that infiltrate brain tumors of either primary or metastatic origin. Copyright © 2016 Elsevier Inc. All rights reserved.

Pollinator guilds respond differently to urban habitat fragmentation in a oak-savannah ecosystem

USDA-ARS?s Scientific Manuscript database

Habitat fragmentation is widely thought to threaten biodiversity. However, response of pollinators to habitat fragmentation is still poorly understood, as pollinator communities are notoriously spatially variable. We investigated pollinator community structure in a highly fragmented oak-savannah ec...

Effects of ecosystem development on benthic secondary production in restored and created mangrove habitats

EPA Science Inventory

Wetland creation, enhancement, and restoration activities are commonly implemented to compensate for wetland loss or degradation. However, functional equivalence in restored and created wetland habitats is often poorly understood. In estuarine habitats, changes in habitat qualit...

Ozone-Induced Metabolic Impairment is Attenuated in Adrenalectomized Wistar Kyoto Rats

EPA Science Inventory

Rationale: Air pollutants have been linked to increased incidence of metabolic syndrome however the mechanisms are poorly understood. We have recently shown that ozone exposure induces significant hyperglycemia together with elevated serum leptin and epinephrine in the Wistar Ky...

THE INTERACTION OF VAPOUR PHASE ORGANIC COMPOUNDS WITH INDOOR SINKS

EPA Science Inventory

The interaction of indoor air pollutants with interior surfaces (i.e., sinks) is a well known, but poorly understood, phenomenon. Studies have shown that re-emissions of adsorbed organic vapours can contribute to elevated concentrations of organics in indoor environments. Researc...

Preschool Executive Functioning Abilities Predict Early Mathematics Achievement

ERIC Educational Resources Information Center

Clark, Caron A. C.; Pritchard, Verena E.; Woodward, Lianne J.

2010-01-01

Impairments in executive function have been documented in school-age children with mathematical learning difficulties. However, the utility and specificity of preschool executive function abilities in predicting later mathematical achievement are poorly understood. This study examined linkages between children's developing executive function…

HYDRAULIC REDISTRIBUTION IN THE PACIFIC NORTHWEST: TWEAKING THE SYSTEM

EPA Science Inventory

Hydraulic redistribution (HR) has recently been documented in Pacific Northwest forests, but the controls governing this process and its importance to shallow-rooted species are poorly understood. Our objective in this study was to manipulate the soil-root system to tease apart ...

Large sized non-uniform sediment transport at high capacity on steep slopes

NASA Astrophysics Data System (ADS)

Fu, X.; Zhang, L.; Duan, J. G.

2015-12-01

Transport of large-sized particles such as cobbles in steep streams still remains poorly understood in spite of its importance in mountain stream morphdynamics. Here we explored the law of cobble transport and the effect of cobble existence on gravel bed material transport, using flume experiments with a steep slope (4.9%) and water and sediment constantly supplying. The experiments were conducted in an 8 m long and 0.6 m wide circulating flume with the maximal size up to 90 mm and cobble concentrations in the sediment bed ranging from 22 percent to 6 percent. The sediment transport rate is on the order of 1000 g/m/s, which could be taken as high rate transport compared with existing researches. Bed load transport rate and flow variables were measured after the flume reached an equilibrium state. Bed surface topography was also measured by applying Kinect range camera before and after each run in order to analyze the fractal characteristics of the bed surface under different flow conditions. Critical shear stress of each size friction was estimated from the reference transport method (RTM) and a new hiding function was recommended. Preliminary results show that the bed was nearly in an equal mobility transport regime. We then plot dimensionless fractional transport rate versus dimensionless shear stress and assess the existing bed load transport formulas of non-uniform sediments for their applicability at high sediment transport capacity. This study contributes to the comprehension of high rate sediment transport on steep slopes.

Kinetic Dissection of the Pre-existing Conformational Equilibrium in the Trypsin Fold*

PubMed Central

Vogt, Austin D.; Chakraborty, Pradipta; Di Cera, Enrico

2015-01-01

Structural biology has recently documented the conformational plasticity of the trypsin fold for both the protease and zymogen in terms of a pre-existing equilibrium between closed (E*) and open (E) forms of the active site region. How such plasticity is manifested in solution and affects ligand recognition by the protease and zymogen is poorly understood in quantitative terms. Here we dissect the E*-E equilibrium with stopped-flow kinetics in the presence of excess ligand or macromolecule. Using the clotting protease thrombin and its zymogen precursor prethrombin-2 as relevant models we resolve the relative distribution of the E* and E forms and the underlying kinetic rates for their interconversion. In the case of thrombin, the E* and E forms are distributed in a 1:4 ratio and interconvert on a time scale of 45 ms. In the case of prethrombin-2, the equilibrium is shifted strongly (10:1 ratio) in favor of the closed E* form and unfolds over a faster time scale of 4.5 ms. The distribution of E* and E forms observed for thrombin and prethrombin-2 indicates that zymogen activation is linked to a significant shift in the pre-existing equilibrium between closed and open conformations that facilitates ligand binding to the active site. These findings broaden our mechanistic understanding of how conformational transitions control ligand recognition by thrombin and its zymogen precursor prethrombin-2 and have direct relevance to other members of the trypsin fold. PMID:26216877

Unusual dewetting of thin polymer films in liquid media containing a poor solvent and a nonsolvent.

PubMed

Xu, Lin; Sharma, Ashutosh; Joo, Sang Woo; Liu, Hui; Shi, Tongfei

2014-12-16

We investigate the control of pattern size and kinetics in spontaneous dewetting of thin polymer films (polystyrene) that are stable to thermal annealing by annealing in a poor solvent (acetone)/nonsolvent (ethanol or n-hexane) liquid mixture. Dewetting occurs by the formation and growth of circular holes that coalesce to form droplets. The influence of the nature and the volume fraction of the nonsolvents on the contact angle of polymer droplets, number density of holes, and the kinetics of holes formation and growth is studied. Addition of ethanol greatly increases the hole density and slows down the kinetics substantially, while affecting only a small change in wettability. n-Hexane addition shows an interesting nonmonotonic response in decreasing the hole density and contact angle in the volume fraction range of 0-0.3 but an opposite effect beyond that. Although the two nonsolvents chosen cannot by themselves induce dewetting, their relative affinity for the solid substrate vis-à-vis acetone can strongly influence the observed dewetting scenarios that are not understood by the existing theoretical considerations. n-Hexane, for example, has great affinity for silicon substrate. In addition to the changes in wettability, viscosity, and film interfacial tension engendered by the nonsolvents, the possibility of the formation of adsorbed liquid layers at the substrate-polymer interface, which can modify the interfacial friction and slippage, needs to be considered.

REVIEWING HIV-RELATED RESEARCH IN EMERGING ECONOMIES: THE ROLE OF GOVERNMENT REVIEWING AGENCIES

PubMed Central

Klitzman, Robert; Sexton, Patrina; Hui, Katrina; Hanrahan, Donna; Barnes, Mark; Sugarman, Jeremy; London, Alex John

2015-01-01

Little research has explored the possible effects of government institutions in emerging economies on ethical reviews of multinational research. We conducted semi-structured, in-depth telephone interviews with 15 researchers, Research Ethics Committees (RECs) personnel, and a government agency member involved in multinational HIV Prevention Trials Network (HPTN) research in emerging economies. Ministries of Health (MOH) or other government agencies often play pivotal roles as facilitators or barriers in the research ethics approval process. Government agency RECs reviewing protocols may face particular challenges, as they can lack resources, be poorly organized, have inconsistent review processes and, limited expertise, use differing definitions of national interests, including upholding national reputation and avoiding potential exploitation and stigma of the country’s population. The MOH/governmental review body may be affected by power dynamics and politics in study reviews; may consider issues both related and unrelated to research ethics as understood elsewhere; and may prioritize particular diseases, treatments, or interventions over other topics/types of research. Poor communication and deeply-rooted tensions may exist between sponsor and host countries, impeding optimal interactions and reviews. Investigators must understand and plan for the potential effects of governmental agencies on multinational collaborative research, including preserving adequate time for agency review, and contacting these agencies beforehand to address issues that may arise. Better understanding of these issues can aid and advance appropriate global scientific collaboration. PMID:25388003

Intraspecific Variation among Social Insect Colonies: Persistent Regional and Colony-Level Differences in Fire Ant Foraging Behavior

PubMed Central

Bockoven, Alison A.; Wilder, Shawn M.; Eubanks, Micky D.

2015-01-01

Individuals vary within a species in many ecologically important ways, but the causes and consequences of such variation are often poorly understood. Foraging behavior is among the most profitable and risky activities in which organisms engage and is expected to be under strong selection. Among social insects there is evidence that within-colony variation in traits such as foraging behavior can increase colony fitness, but variation between colonies and the potential consequences of such variation are poorly documented. In this study, we tested natural populations of the red imported fire ant, Solenopsis invicta, for the existence of colony and regional variation in foraging behavior and tested the persistence of this variation over time and across foraging habitats. We also reared single-lineage colonies in standardized environments to explore the contribution of colony lineage. Fire ants from natural populations exhibited significant and persistent colony and regional-level variation in foraging behaviors such as extra-nest activity, exploration, and discovery of and recruitment to resources. Moreover, colony-level variation in extra-nest activity was significantly correlated with colony growth, suggesting that this variation has fitness consequences. Lineage of the colony had a significant effect on extra-nest activity and exploratory activity and explained approximately half of the variation observed in foraging behaviors, suggesting a heritable component to colony-level variation in behavior. PMID:26197456

Reviewing HIV-Related Research in Emerging Economies: The Role of Government Reviewing Agencies.

PubMed

Sexton, Patrina; Hui, Katrina; Hanrahan, Donna; Barnes, Mark; Sugarman, Jeremy; London, Alex John; Klitzman, Robert

2016-04-01

Little research has explored the possible effects of government institutions in emerging economies on ethical reviews of multinational research. We conducted semi-structured, in-depth telephone interviews with 15 researchers, Research Ethics Committees (RECs) personnel, and a government agency member involved in multinational HIV Prevention Trials Network (HPTN) research in emerging economies. Ministries of Health (MOH) or other government agencies often play pivotal roles as facilitators or barriers in the research ethics approval process. Government agency RECs reviewing protocols may face particular challenges, as they can lack resources, be poorly organized, have inconsistent review processes and limited expertise, and use differing definitions of national interests, including upholding national reputation and avoiding potential exploitation and stigma of the country's population. The MOH/governmental review body may be affected by power dynamics and politics in study reviews; may consider issues both related and unrelated to research ethics as understood elsewhere; and may prioritize particular diseases, treatments, or interventions over other topics/types of research. Poor communication and deeply-rooted tensions may exist between sponsor and host countries, impeding optimal interactions and reviews. Investigators must understand and plan for the potential effects of governmental agencies on multinational collaborative research, including preserving adequate time for agency review, and contacting these agencies beforehand to address issues that may arise. Better understanding of these issues can aid and advance appropriate global scientific collaboration. © 2014 John Wiley & Sons Ltd.

Hybrid quantum and molecular mechanics embedded cluster models for chemistry on silicon and silicon carbide surfaces

NASA Astrophysics Data System (ADS)

Shoemaker, James Richard

Fabrication of silicon carbide (SiC) semiconductor devices are of interest for aerospace applications because of their high-temperature tolerance. Growth of an insulating SiO2 layer on SiC by oxidation is a poorly understood process, and sometimes produces interface defects that degrade device performance. Accurate theoretical models of surface chemistry, using quantum mechanics (QM), do not exist because of the huge computational cost of solving Schrodinger's equation for a molecular cluster large enough to represent a surface. Molecular mechanics (MM), which describes a molecule as a collection of atoms interacting through classical potentials, is a fast computational method, good at predicting molecular structure, but cannot accurately model chemical reactions. A new hybrid QM/MM computational method for surface chemistry was developed and applied to silicon and SiC surfaces. The addition of MM steric constraints was shown to have a large effect on the energetics of O atom adsorption on SiC. Adsorption of O atoms on Si-terminated SiC(111) favors above surface sites, in contrast to Si(111), but favors subsurface adsorption sites on C- terminated SiC(111). This difference, and the energetics of C atom etching via CO2 desorption, can explain the observed poor performance of SiC devices in which insulating layers were grown on C-terminated surfaces.

A formative evaluation of the implementation of a medication safety data collection tool in English healthcare settings: A qualitative interview study using normalisation process theory.

PubMed

Rostami, Paryaneh; Ashcroft, Darren M; Tully, Mary P

2018-01-01

Reducing medication-related harm is a global priority; however, impetus for improvement is impeded as routine medication safety data are seldom available. Therefore, the Medication Safety Thermometer was developed within England's National Health Service. This study aimed to explore the implementation of the tool into routine practice from users' perspectives. Fifteen semi-structured interviews were conducted with purposely sampled National Health Service staff from primary and secondary care settings. Interview data were analysed using an initial thematic analysis, and subsequent analysis using Normalisation Process Theory. Secondary care staff understood that the Medication Safety Thermometer's purpose was to measure medication safety and improvement. However, other uses were reported, such as pinpointing poor practice. Confusion about its purpose existed in primary care, despite further training, suggesting unsuitability of the tool. Decreased engagement was displayed by staff less involved with medication use, who displayed less ownership. Nonetheless, these advocates often lacked support from management and frontline levels, leading to an overall lack of engagement. Many participants reported efforts to drive scale-up of the use of the tool, for example, by securing funding, despite uncertainty around how to use data. Successful improvement was often at ward-level and went unrecognised within the wider organisation. There was mixed feedback regarding the value of the tool, often due to a perceived lack of "capacity". However, participants demonstrated interest in learning how to use their data and unexpected applications of data were reported. Routine medication safety data collection is complex, but achievable and facilitates improvements. However, collected data must be analysed, understood and used for further work to achieve improvement, which often does not happen. The national roll-out of the tool has accelerated shared learning; however, a number of difficulties still exist, particularly in primary care settings, where a different approach is likely to be required.

A formative evaluation of the implementation of a medication safety data collection tool in English healthcare settings: A qualitative interview study using normalisation process theory

PubMed Central

Ashcroft, Darren M.; Tully, Mary P.

2018-01-01

Background Reducing medication-related harm is a global priority; however, impetus for improvement is impeded as routine medication safety data are seldom available. Therefore, the Medication Safety Thermometer was developed within England’s National Health Service. This study aimed to explore the implementation of the tool into routine practice from users’ perspectives. Method Fifteen semi-structured interviews were conducted with purposely sampled National Health Service staff from primary and secondary care settings. Interview data were analysed using an initial thematic analysis, and subsequent analysis using Normalisation Process Theory. Results Secondary care staff understood that the Medication Safety Thermometer’s purpose was to measure medication safety and improvement. However, other uses were reported, such as pinpointing poor practice. Confusion about its purpose existed in primary care, despite further training, suggesting unsuitability of the tool. Decreased engagement was displayed by staff less involved with medication use, who displayed less ownership. Nonetheless, these advocates often lacked support from management and frontline levels, leading to an overall lack of engagement. Many participants reported efforts to drive scale-up of the use of the tool, for example, by securing funding, despite uncertainty around how to use data. Successful improvement was often at ward-level and went unrecognised within the wider organisation. There was mixed feedback regarding the value of the tool, often due to a perceived lack of “capacity”. However, participants demonstrated interest in learning how to use their data and unexpected applications of data were reported. Conclusion Routine medication safety data collection is complex, but achievable and facilitates improvements. However, collected data must be analysed, understood and used for further work to achieve improvement, which often does not happen. The national roll-out of the tool has accelerated shared learning; however, a number of difficulties still exist, particularly in primary care settings, where a different approach is likely to be required. PMID:29489842

HIV in (and out of) the clinic: biomedicine, traditional medicine and spiritual healing in Harare.

PubMed

O'Brien, Stephen; Broom, Alex

2014-01-01

Contemporary lived experiences of the human immunodeficiency virus (HIV) are shaped by clinical and cultural encounters with illness. In sub-Saharan countries such as Zimbabwe, HIV is treated in very different ways in various therapeutic contexts including by biomedical experts, traditional medicine and faith healers. The co-existence of such expertise raises important questions around the potencies and limits of medicalisation and alternative healing practices in promoting HIV recovery. First, in this study, drawing on in-depth qualitative interviews with 60 people from poor urban areas in Harare, we explore the experiences of people living with and affected by HIV. Specifically, we sought to document, interrogate and reflect on their perceptions and experiences of biomedicine in relation to traditional medicine and spiritual healing. Their accounts indicate that traditional medicine and spiritual beliefs continue to significantly influence the way in which HIV is understood, and the forms of help and care people seek. Second, we observe the dramatic and overwhelmingly beneficial impact of Antiretroviral Therapy and conclude through Zimbabwean's own stories that limitations around delivery and wider structural inequalities impede its potential. Lastly, we explore some practical implications of the biomedical clinic (and alternative healing practices) being understood as sites of ideological and expert contestation. This paper aimed to add to our knowledge of the relationships between traditional medicine and spiritual healing in connection with biomedicine and how this may influence HIV treatment and prevention.

HIV in (and out of) the clinic: Biomedicine, traditional medicine and spiritual healing in Harare

PubMed Central

O'Brien, Stephen; Broom, Alex

2014-01-01

Abstract Contemporary lived experiences of the human immunodeficiency virus (HIV) are shaped by clinical and cultural encounters with illness. In sub-Saharan countries such as Zimbabwe, HIV is treated in very different ways in various therapeutic contexts including by biomedical experts, traditional medicine and faith healers. The co-existence of such expertise raises important questions around the potencies and limits of medicalisation and alternative healing practices in promoting HIV recovery. First, in this study, drawing on in-depth qualitative interviews with 60 people from poor urban areas in Harare, we explore the experiences of people living with and affected by HIV. Specifically, we sought to document, interrogate and reflect on their perceptions and experiences of biomedicine in relation to traditional medicine and spiritual healing. Their accounts indicate that traditional medicine and spiritual beliefs continue to significantly influence the way in which HIV is understood, and the forms of help and care people seek. Second, we observe the dramatic and overwhelmingly beneficial impact of Antiretroviral Therapy and conclude through Zimbabwean's own stories that limitations around delivery and wider structural inequalities impede its potential. Lastly, we explore some practical implications of the biomedical clinic (and alternative healing practices) being understood as sites of ideological and expert contestation. This paper aimed to add to our knowledge of the relationships between traditional medicine and spiritual healing in connection with biomedicine and how this may influence HIV treatment and prevention. PMID:25017937

IN-STREAM AND WATERSHED PREDICTORS OF GENETIC DIVERSITY, EFFECTIVE POPULATION SIZE AND IMMIGRATION ACROSS RIVER-STREAM NETWORKS

EPA Science Inventory

The influence of spatial processes on population dynamics within river-stream networks is poorly understood. Utilizing spatially explicit analyses of temporal genetic variance, we examined whether persistence of Central Stonerollers (Campostoma anomalum) reflects differences in h...

Worldwide patterns of ancestry, divergence, and admixture in domesticated cattle

USDA-ARS?s Scientific Manuscript database

The domestication and development of cattle has considerably impacted human societies, but the histories of cattle breeds have been poorly understood especially for African, Asian, and American breeds. Using genotypes from 43,043 autosomal single nucleotide polymorphism markers scored in 1,543 anima...

WWW: The Scientific Method

ERIC Educational Resources Information Center

Blystone, Robert V.; Blodgett, Kevin

2006-01-01

The scientific method is the principal methodology by which biological knowledge is gained and disseminated. As fundamental as the scientific method may be, its historical development is poorly understood, its definition is variable, and its deployment is uneven. Scientific progress may occur without the strictures imposed by the formal…

From Movements to Actions: Two Mechanisms for Learning Action Sequences

ERIC Educational Resources Information Center

Endress, Ansgar D.; Wood, Justin N.

2011-01-01

When other individuals move, we interpret their movements as discrete, hierarchically-organized, goal-directed actions. However, the mechanisms that integrate visible movement features into actions are poorly understood. Here, we consider two sequence learning mechanisms--transitional probability-based (TP) and position-based encoding…

Accumulation of the Antibiotic Phenazine-1-Carboxylic Acid in the Rhizosphere of Dryland Cereals

USDA-ARS?s Scientific Manuscript database

Natural antibiotics are thought to function in the defense, fitness, competitiveness, biocontrol activity, communication and gene regulation of microorganisms. However, the scale and quantitative aspects of antibiotic production in natural settings are poorly understood. We addressed these fundament...

Size matters: The contribution of mega-infauna to the food webs and ecosystem services of an Oregon estuary - ESA

EPA Science Inventory

Background/Questions/Methods Large-bodied invertebrates (bivalves, polychaetes, burrowing shrimps) are common to infaunal communities of NE Pacific estuaries, but their contribution to estuarine community structure, function and ecosystem services is poorly understood because ...

Olfactory disruption: towards controlling important insect vectors of disease

USDA-ARS?s Scientific Manuscript database

Chemical repellents are used to decrease contacts between insect disease vectors and their hosts, thus reducing the probability of disease transmission. The molecular mechanisms by which repellents have their effects are poorly understood and remain a controversial topic. Here we present recent re...

Environmental enteric dysfunction is associated with carnitine deficiency and altered fatty acid oxidation

USDA-ARS?s Scientific Manuscript database

Environmental enteric dysfunction (EED), a condition characterized by small intestine inflammation and abnormal gut permeability, is widespread in children in developing countries and a major cause of growth failure. The pathophysiology of EED remains poorly understood. We measured serum metabolite...

LOCAL VS. REGIONAL EFFECTS ON FISH DIVERSITY AS MEDIATED BY STREAMFLOW DISTURBANCE REGIME

EPA Science Inventory

abstract

The interplay of local and regional processes on fish diversity is poorly understood, especially related to patterns of streamflow disturbance regime. Articulation of the relationship between flow disturbance patterns and river fishes across local to regional scal...

Disruption of the circadian clock within the cardiomyocyte influences mycardial contractile function, metabolism, and gene expression

USDA-ARS?s Scientific Manuscript database

Virtually every mammalian cell, including cardiomyocytes, possesses an intrinsic circadian clock. The role of this transcriptionally based molecular mechanism in cardiovascular biology is poorly understood. We hypothesized that the circadian clock within the cardiomyocyte influences diurnal variatio...

The role of methionine metabolism in inflammatory bowel disease

USDA-ARS?s Scientific Manuscript database

Methionine (Met) cycle activity is critical for normal cell functions. Met metabolites S-adenosylmethionine (SAM) and methylthioadenosine (MTA) are anti-inflammatory, yet their role in inflammatory bowel disease (IBD) is poorly understood. We hypothesize that active IBD leads to changes in Met metab...

Molecular basis for the thermostability of Newcastle disease virus

USDA-ARS?s Scientific Manuscript database

Thermostable Newcastle disease virus (NDV) vaccines have been used widely to protect village chickens against Newcastle disease, due to their decreased dependence on cold chain for transport and storage. However, the genetic basis underlying the NDV thermostability is poorly understood. In this stud...

Development and preliminary validation of the Parenting around SNAcking Questionnaire (P-SNAQ)

USDA-ARS?s Scientific Manuscript database

Snacking makes significant contributions to children's dietary intake but is poorly understood from a parenting perspective. This research was designed to develop and evaluate the psychometrics of a theoretically grounded, empirically-informed measure of snack parenting. The Parenting around SNAckin...

Do boll weevils really diapause?

USDA-ARS?s Scientific Manuscript database

Boll weevil, Anthonomus grandis grandis Boheman, diapause has been poorly understood since the term was first used 50 yrs ago to describe the pest’s winter dormancy in temperate regions. This literature-based study found that low temperature and changes in photoperiod are the boll weevil diapause-i...

Effects of exurban development on trophic interactions in a desert landscape

USDA-ARS?s Scientific Manuscript database

Context Mechanisms of ecosystem change in urbanizing landscapes are poorly understood, especially in exurban areas featuring residential or commercial development set in a matrix of modified and natural vegetation. We asked how development altered trophic interactions and ecosystem processes in the ...

Light absorption of secondary organic aerosol: Composition and contribution of nitro-aromatic compounds

EPA Science Inventory

Secondary organic aerosol (SOA) might affect the atmospheric radiation balance through absorbing light at shorter visible and UV wavelengths. However, the composition and optical properties of light-absorbing SOA is poorly understood. In this work, SOA filter samples were collect...

Reproductive responses of northern goshawks to variable prey populations

Treesearch

Susan R. Salafsky; Richard T. Reynolds; Barry R. Noon; John A. Wiens

2007-01-01

Developing comprehensive conservation strategies requires knowledge of factors influencing population growth and persistence. Although variable prey resources are often associated with fluctuations in raptor demographic parameters, the mechanisms of food limitation are poorly understood, especially for a generalist predator like the northern goshawk (Accipiter...

The dark side of suibsidies: quantifying contaminant exposure to riparian predators via stream insects

EPA Science Inventory

Aquatic insects provide a critical nutrient subsidy to riparian food webs, yet their role as vectors of contaminants to terrestrial ecosystems is poorly understood. We investigated relationships between aquatic (resource utilization) and contaminant exposure for a riparian invert...

The geography of spatial synchrony

Treesearch

Jonathan A. Walter; Lawrence W. Sheppard; Thomas L. Anderson; Jude H. Kastens; Ottar N. Bjørnstad; Andrew M. Liebhold; Daniel C. Reuman; Bernd Blasius

2017-01-01

Spatial synchrony, defined as correlated temporal fluctuations among populations, is a fundamental feature of population dynamics, but many aspects of synchrony remain poorly understood. Few studies have examined detailed geographical patterns of synchrony; instead most focus on how synchrony declines with increasing linear distance between locations, making the...

Relations between Alcohol, Violence and Victimization in Adolescence

ERIC Educational Resources Information Center

Shepherd, J. P.; Sutherland, I.; Newcombe, R. G.

2006-01-01

Background: Compared to links between alcohol and aggression, links between alcohol and vulnerability are poorly understood. Objectives: To determine whether there is a significant relationship between vulnerability to physical violence and alcohol consumption in adolescence independent of a relationship between alcohol consumption and violent…

Heredity Factors in Spatial Visualization.

ERIC Educational Resources Information Center

Vandenberg, S. G.

Spatial visualization is not yet clearly understood. Some researchers have concluded that two factors or abilities are involved, spatial orientation and spatial visualization. Different definitions and different tests have been proposed for these two abilities. Several studies indicate that women generally perform more poorly on spatial tests than…

Ecosystem Development after Mangrove Wetland Creation: Plant-Soil Change across a 20-year Chronosequence

EPA Science Inventory

Mangrove wetland restoration and creation efforts are increasingly proposed as mechanisms to compensate for mangrove wetland loss. However, ecosystem development and functional equivalence in restored and created mangrove wetlands is poorly understood. We compared a 20-yr chrono...

Working Model Hearts

ERIC Educational Resources Information Center

Brock, David

2009-01-01

Despite student interest, the heart is often a poorly understood topic in biology. To help students understand this vital organ's physiology, the author created this investigation activity involving the mammalian heart and its role in the circulatory system. Students design, build, and demonstrate working artificial "hearts" to exhibit what they…

Technology-Enhanced Discovery

ERIC Educational Resources Information Center

Harrow, Chris; Chin, Lillian

2014-01-01

Exploration, innovation, proof: For students, teachers, and others who are curious, keeping an open mind and being ready to investigate unusual or unexpected properties will always lead to learning something new. Technology can further this process, allowing various behaviors to be analyzed that were previously memorized or poorly understood. This…

Multi-scale assessment of human-induced changes to Amazonian instream habitats

EPA Science Inventory

Context: Land use change and forest degradation have myriad effects on tropical ecosystems. Yet their consequences for low-order streams remain very poorly understood, including in the world´s largest freshwater basin, the Amazon.Objectives: Determine the degree to which ph...

Child stunting is associated with low circulating essential amino acids

USDA-ARS?s Scientific Manuscript database

Stunting affects about one-quarter of children under five worldwide. The pathogenesis of stunting is poorly understood. Nutritional interventions have had only modest effects in reducing stunting. We hypothesized that insufficiency in essential amino acids may be limiting the linear growth of childr...

Introduction to the Thematic Minireview Series: Brain glycogen metabolism.

PubMed

Carlson, Gerald M; Dienel, Gerald A; Colbran, Roger J

2018-05-11

The synthesis of glycogen allows for efficient intracellular storage of glucose molecules in a soluble form that can be rapidly released to enter glycolysis in response to energy demand. Intensive studies of glucose and glycogen metabolism, predominantly in skeletal muscle and liver, have produced innumerable insights into the mechanisms of hormone action, resulting in the award of several Nobel Prizes over the last one hundred years. Glycogen is actually present in all cells and tissues, albeit at much lower levels than found in muscle or liver. However, metabolic and physiological roles of glycogen in other tissues are poorly understood. This series of Minireviews summarizes what is known about the enzymes involved in brain glycogen metabolism and studies that have linked glycogen metabolism to multiple brain functions involving metabolic communication between astrocytes and neurons. Recent studies unexpectedly linking some forms of epilepsy to mutations in two poorly understood proteins involved in glycogen metabolism are also reviewed. © 2018 Carlson et al.

Immigrant dairy workers' perceptions of health and safety on the farm in America's Heartland.

PubMed

Liebman, Amy King; Juarez-Carrillo, Patricia Margarita; Reyes, Iris Anne Cruz; Keifer, Matthew Charles

2016-03-01

Dairy farming is dangerous. Yearly, farms grow fewer and larger by employing immigrant workers, who have limited industrial agriculture experience and safety and health training. We examined results of five focus groups with 37 Hispanic, immigrant dairy workers. Analysis followed a grounded theory approach and employed ATLAS.ti. Reported injury experience affirmed the hazardous nature of dairy. Some workers received appropriate worker compensation benefits, whereas others were instructed to deny work-relatedness. Some employers covered medical injury costs out-of-pocket, whereas others did not. Cows were a major injury source. Pressure to work and weather were noted as injury risk factors. Worker compensation was poorly understood, and immigration status and fear of deportation influenced injury and hazard reporting. Injury management practices range from benevolent to threatening. Workers compensation is poorly understood and undocumented status is an occupational hazard. We underscore the need for further research and immigration policy change. © 2015 Wiley Periodicals, Inc.

Direct observation of closed magnetic flux trapped in the high-latitude magnetosphere.

PubMed

Fear, R C; Milan, S E; Maggiolo, R; Fazakerley, A N; Dandouras, I; Mende, S B

2014-12-19

The structure of Earth's magnetosphere is poorly understood when the interplanetary magnetic field is northward. Under this condition, uncharacteristically energetic plasma is observed in the magnetotail lobes, which is not expected in the textbook model of the magnetosphere. Using satellite observations, we show that these lobe plasma signatures occur on high-latitude magnetic field lines that have been closed by the fundamental plasma process of magnetic reconnection. Previously, it has been suggested that closed flux can become trapped in the lobe and that this plasma-trapping process could explain another poorly understood phenomenon: the presence of auroras at extremely high latitudes, called transpolar arcs. Observations of the aurora at the same time as the lobe plasma signatures reveal the presence of a transpolar arc. The excellent correspondence between the transpolar arc and the trapped closed flux at high altitudes provides very strong evidence of the trapping mechanism as the cause of transpolar arcs. Copyright © 2014, American Association for the Advancement of Science.

Sea-level-induced seismicity and submarine landslide occurrence

USGS Publications Warehouse

Brothers, Daniel S.; Luttrell, Karen M.; Chaytor, Jason D.

2013-01-01

The temporal coincidence between rapid late Pleistocene sea-level rise and large-scale slope failures is widely documented. Nevertheless, the physical mechanisms that link these phenomena are poorly understood, particularly along nonglaciated margins. Here we investigate the causal relationships between rapid sea-level rise, flexural stress loading, and increased seismicity rates along passive margins. We find that Coulomb failure stress across fault systems of passive continental margins may have increased more than 1 MPa during rapid late Pleistocene–early Holocene sea-level rise, an amount sufficient to trigger fault reactivation and rupture. These results suggest that sea-level–modulated seismicity may have contributed to a number of poorly understood but widely observed phenomena, including (1) increased frequency of large-scale submarine landslides during rapid, late Pleistocene sea-level rise; (2) emplacement of coarse-grained mass transport deposits on deep-sea fans during the early stages of marine transgression; and (3) the unroofing and release of methane gas sequestered in continental slope sediments.

Cortical dendritic activity correlates with spindle-rich oscillations during sleep in rodents.

PubMed

Seibt, Julie; Richard, Clément J; Sigl-Glöckner, Johanna; Takahashi, Naoya; Kaplan, David I; Doron, Guy; de Limoges, Denis; Bocklisch, Christina; Larkum, Matthew E

2017-09-25

How sleep influences brain plasticity is not known. In particular, why certain electroencephalographic (EEG) rhythms are linked to memory consolidation is poorly understood. Calcium activity in dendrites is known to be necessary for structural plasticity changes, but this has never been carefully examined during sleep. Here, we report that calcium activity in populations of neocortical dendrites is increased and synchronised during oscillations in the spindle range in naturally sleeping rodents. Remarkably, the same relationship is not found in cell bodies of the same neurons and throughout the cortical column. Spindles during sleep have been suggested to be important for brain development and plasticity. Our results provide evidence for a physiological link of spindles in the cortex specific to dendrites, the main site of synaptic plasticity.Different stages of sleep, marked by particular electroencephalographic (EEG) signatures, have been linked to memory consolidation, but underlying mechanisms are poorly understood. Here, the authors show that dendritic calcium synchronisation correlates with spindle-rich sleep phases.

A missed Fe-S cluster handoff causes a metabolic shakeup.

PubMed

Berteau, Olivier

2018-05-25

The general framework of pathways by which iron-sulfur (Fe-S) clusters are assembled in cells is well-known, but the cellular consequences of disruptions to that framework are not fully understood. Crooks et al. report a novel cellular system that creates an acute Fe-S cluster deficiency, using mutants of ISCU, the main scaffold protein for Fe-S cluster assembly. Surprisingly, the resultant metabolic reprogramming leads to the accumulation of lipid droplets, a situation encountered in many poorly understood pathological conditions, highlighting unanticipated links between Fe-S assembly machinery and human disease. © 2018 Berteau.

The mystery of a supposed massive star exploding in a brightest cluster galaxy

NASA Astrophysics Data System (ADS)

Hosseinzadeh, Griffin

2017-08-01

Most of the diversity of core-collapse supernovae results from late-stage mass loss by their progenitor stars. Supernovae that interact with circumstellar material (CSM) are a particularly good probe of these last stages of stellar evolution. Type Ibn supernovae are a rare and poorly understood class of hydrogen-poor explosions that show signs of interaction with helium-rich CSM. The leading hypothesis is that they are explosions of very massive Wolf-Rayet stars in which the supernova ejecta excites material previously lost by stellar winds. These massive stars have very short lifetimes, and therefore should only found in actively star-forming galaxies. However, PS1-12sk is a Type Ibn supernova found on the outskirts of a giant elliptical galaxy. As this is extraordinary unlikely, we propose to obtain deep UV images of the host environment of PS1-12sk in order to map nearby star formation and/or find a potential unseen star-forming host. If star formation is detected, its amount and location will provide deep insights into the progenitor picture for the poorly-understood Type Ibn class. If star formation is still not detected, these observations would challenge the well-accepted hypothesis that these are core-collapse supernovae at all.

Annual Research Review: Improved nutrition--pathway to resilience.

PubMed

Yousafzai, Aisha K; Rasheed, Muneera A; Bhutta, Zulfiqar A

2013-04-01

Early child nutritional deficiencies are prevalent in low- and middle-countries with consequences linked not only to poor survival and growth, but also to poor development outcomes. Children in disadvantaged communities face multiple risks for nutritional deficiencies, yet some children may be less susceptible or may recover more quickly from malnutrition. A greater understanding is needed about factors which moderate the effects of nutrition-related risks and foster resilience to protect against or ameliorate poor development outcomes. A literature review was undertaken from August to December 2011 and updated in August 2012. Key word searches using terms Nutrition, Malnutrition, Child Development, Responsive Care, Stimulation, Low and Middle Income Countries and Resilience were undertaken using PubMed and Psychinfo. Dietary adequacy is critical for growth and development, but current evidence indicates that nutrition supplementation alone is insufficient to foster resilience to protect against, mitigate, and recover from nutritional threats and to promote healthy development. The combination of nutrition interventions with stimulation and responsive care is necessary. Combined nutrition and psychosocial stimulation approaches can potentially work effectively together to promote protective factors and mitigate risks for poor cognitive, motor, social, and affective functioning helping children to adapt in times of adversity. However, there are gaps in our existing knowledge to combine nutrition and psychosocial stimulation interventions effectively and promote these interventions at scale. Research needs to address barriers at the level of family, community, programme, and policy which have prevented thus far the uptake of combined nutrition and psychosocial intervention strategies. Further investigations are needed on how to provide support to caregivers, enabling them to implement appropriate care for feeding and stimulation. Finally, the effect of combined interventions on pathways of care and protective mediators that foster resilience need to be better understood to determine focus areas for content of combined intervention curricula which help families in high-risk settings. © 2012 The Authors. Journal of Child Psychology and Psychiatry © 2012 Association for Child and Adolescent Mental Health.

A Physiologically-Based Pharmacokinetic (PBPK) Model With Metabolic Interactions of Chloroform (CHCL3) and Trichloroethylene

EPA Science Inventory

Exposure to mixtures is frequent, but biologic pathways such as metabolic inhibition, are poorly understood. CHCl3 and TCE are model volatiles frequently co-occurring; combined exposure results in less than additive hepatotoxicity. Here, we explore the underlying metabolic inte...

Advanced Pavement Design: Finite Element Modeling for Rigid Pavement Joints, Report II: Model Development

DOT National Transportation Integrated Search

1998-03-01

The contribution of a cement-stabilized base course to the strength of the rigid pavement structure is poorly understood. The objective of this research was to obtain data on the response of the rigid pavement slab-joint-foundation system by conducti...

Integrating Demographic, Clinical,and Environmental Exposure Information to Identify Genomic Biomarkers Associated With Subtypes of Childhood Asthma

EPA Science Inventory

Childhood asthma is a multifactorial disease with a disturbingly high incidence in urbanized areas. The pathogenesis of asthma is poorly understood due to the complex relationship between genetic susceptibility and modulating environmental factors. The Mechanistic Indicators of C...

NITROGEN OUTPUTS FROM FECAL AND URINE DEPOSITION OF SMALL MAMMALS: IMPLICATIONS FOR NITROGEN CYCLING

EPA Science Inventory

The contribution of small mammals to nitrogen cycling is poorly understood, but it could have reverberations back to the producer community by maintaining or perhaps magnifying nitrogen availability. Our objective was to model nitrogen outputs (deposition of feces and urine) of ...

Accumulation of the antibiotic phenazine-1-carboxylic acid in the rhizosphere of dryland cereals

USDA-ARS?s Scientific Manuscript database

Natural antibiotics are thought to function in microbial defense, fitness, competitiveness, biocontrol, communication and gene regulation. However, the frequency and amount of antibiotics produced in nature are poorly understood. In this study, we assessed the geographic distribution of indigenous p...

Genomic medicine and ethnic differences in cardiovascular disease risk

USDA-ARS?s Scientific Manuscript database

The origins of health disparities are a poorly understood public health problem. The effects of culture, environmental hazards, and social marginalization differ between ethnicities and have strong effects on health differences. The role of the genome in health is well established and we present a s...

Extreme Precipitation and Emergency Room Visits for Influenza in Massachusetts: A Case-Crossover Analysis

EPA Science Inventory

BACKGROUND: Influenza peaks during the wintertime in temperate regions and during the annual rainy season in tropical regions – however reasons for the observed differences in disease ecology are poorly understood. We hypothesize that episodes of extreme precipitation also result...

Interdependence of endomembrane trafficking and actin dynamics during polarized growth of Arabidopsis pollen tubes

USDA-ARS?s Scientific Manuscript database

During polarized growth of pollen tubes, endomembrane trafficking and actin polymerization are two critical processes that establish membrane/wall homeostasis and maintain growth polarity. Fine-tuned interactions between these two processes are therefore necessary but poorly understood. To better un...

Evaluating the relationship between the driver and roadway to address rural intersection safety using the SHRP 2 naturalistic driving study data.

DOT National Transportation Integrated Search

2016-02-01

Rural intersections account for 30% of crashes in rural areas and 6% of all fatal crashes, representing a significant but poorly : understood safety problem. Transportation agencies have traditionally implemented countermeasures to address rural inte...

Flavonoids, alkali earth and rare earth elements affect germination of pecan pollen

USDA-ARS?s Scientific Manuscript database

The factors regulating pecan [Carya illinoinensis (Wangenh.) K. Koch] pollen grain germination on receptive stigmatic flower surfaces in vivo or in vitro in pollen viability assays are poorly understood. While there are many potential regulating factors, there is evidence for involvement of flavonol...

Neural Correlates of Socioeconomic Status in the Developing Human Brain

ERIC Educational Resources Information Center

Noble, Kimberly G.; Houston, Suzanne M.; Kan, Eric; Sowell, Elizabeth R.

2012-01-01

Socioeconomic disparities in childhood are associated with remarkable differences in cognitive and socio-emotional development during a time when dramatic changes are occurring in the brain. Yet, the neurobiological pathways through which socioeconomic status (SES) shapes development remain poorly understood. Behavioral evidence suggests that…

Gastrointestinal toxicity, systemic inflammation, and liver biochemistry in allogeneic hematopoietic stem cell transplantation

USDA-ARS?s Scientific Manuscript database

Liver toxicity is frequently seen in relation to allogeneic hematopoietic stem cell transplantation (HSCT), but pathogenesis and the risk factors are poorly understood. The purpose of this study was to investigate associations between liver toxicity, gastrointestinal toxicity, and levels of immune-r...

NITROGEN OUTPUTS OF SMALL MAMMALS FROM FECAL AND URINE DEPOSITION: IMPLICATIONS FOR NITROGEN CYCLING

EPA Science Inventory

The contribution of small mammals in nitrogen cycling is poorly understood and could have reverberations back to the producer community by maintaining or even magnifying increased nitrogen availability. Our objective was to model nitrogen outputs (deposition of feces and urine) ...

Feeding behavior and injury caused by Lygus hesperus

USDA-ARS?s Scientific Manuscript database

Despite the importance of Lygus hesperus as a crop pest in the western United States, key aspects of its feeding behavior and consequent injury to cotton are poorly understood. Previous studies of Lygus stage-dependent injury to cotton produced conflicting results. We sought to clarify these relat...

Structural Equations and Causal Explanations: Some Challenges for Causal SEM

ERIC Educational Resources Information Center

Markus, Keith A.

2010-01-01

One common application of structural equation modeling (SEM) involves expressing and empirically investigating causal explanations. Nonetheless, several aspects of causal explanation that have an impact on behavioral science methodology remain poorly understood. It remains unclear whether applications of SEM should attempt to provide complete…

Association between fertilizer-mediated changes in microbial communities and Aedes albopictus growth and survival

USDA-ARS?s Scientific Manuscript database

Contamination of aquatic habitats with anthropogenic nutrients has been associated with an increase in mosquito larval populations but the underlying mechanisms remain poorly understood. We examined the individual and combined effects of two synthetic fertilizers (ammonium sulfate and potassium chlo...

Verbal Understanding and Pavlovian Processes

ERIC Educational Resources Information Center

Tonneau, François

2004-01-01

The behavioral processes through which people react appropriately to verbal descriptions remain poorly understood. I argue here that these processes are Pavlovian. Common objections to a Pavlovian account of symbolic behavior evidence a lack of familiarity with the relevant data or misunderstandings of operant theory. Although much remains to be…

Redefining the Longitude/Latitude Experience with a Scaffolded Geocache

ERIC Educational Resources Information Center

Hammond, Thomas; Bozdin, Alec M.; Stanlick, Sarah E.

2014-01-01

Latitude and longitude are foundational concepts for geography education, yet they are typically poorly understood by students and receive indifferent attention from instructors and publishers' materials. Social studies teachers can take advantage of increasingly ubiquitous geolocating devices such as Global Positions Systems (GPS) to provide…

Wheat streak mosaic virus coat protein is a host-specific long-distance transport determinant in oat

USDA-ARS?s Scientific Manuscript database

Viral determinants involved in systemic infection of hosts by monocot-infecting plant viruses are poorly understood. Wheat streak mosaic virus (WSMV, genus Tritimovirus, family Potyviridae) exclusively infects monocotyledonous crops such as wheat, oat, barley, maize, triticale, and rye. Previously, ...

Genotype-specific responses of apple roots to pathogenic infection by Pythium ultimum

USDA-ARS?s Scientific Manuscript database

Resistance mechanisms employed to defend against soilborne necrotrophic pathogens are poorly understood, particularly with respect to perennial tree fruit crops such as apple. Pythium ultimum is a component of the pathogen complex that incites apple replant disease (ARD). Different levels of tolera...

The Structure of Integral Dimensions: Contrasting Topological and Cartesian Representations

ERIC Educational Resources Information Center

Jones, Matt; Goldstone, Robert L.

2013-01-01

Diverse evidence shows that perceptually integral dimensions, such as those composing color, are represented holistically. However, the nature of these holistic representations is poorly understood. Extant theories, such as those founded on multidimensional scaling or general recognition theory, model integral stimulus spaces using a Cartesian…

Speleothems as Examples of Chemical Equilibrium Processes.

ERIC Educational Resources Information Center

Wilson, James R.

1984-01-01

The chemical formation of speleothems such as stalactites and stalagmites is poorly understood by introductory geology instructors and misrepresented in most textbooks. Although evaporation may be a controlling factor in some caves, it is necessary to consider chemical precipitation as more important in controlling the diagenesis of calcium…

Aboveground and belowground net primary production

Treesearch

Hal O. Liechty; Mark H. Eisenbies

2000-01-01

The relationship among net primary productivity (NPP), hydroperiod, and fertility in forested wetlands is poorly understood (Burke and others 1999), particularly with respect to belowground NPP (Megonigal and others 1997). Although some researchers have studied aboveground and belowground primary production in depressional, forested wetland systems, e.g., Day and...

Remote Sensing and Underwater Glider Observations of a Springtime Plume in Western Lake Superior

EPA Science Inventory

Plumes are commonly observed in satellite imagery of western Lake Superior following storm events, and represent a significant cross-shelf pathway for sediment and other constituents. However, their subsurface extent is poorly understood. This study reports results from plume ob...

Effects of Rhododendron maximum L. on Acer rubrum L. Seedling Establishment

Treesearch

Barton D. Clinton; James M. Vose

1996-01-01

Rhododendron maximum L. restricts regeneration of overstory species; however, the mechanisms are poorly understood. Three treatments were used to examine the effects of R. maximum germination success and survival of Acer rubrum L. under a closed overstory canopy: (1) R. maximum understory, (2)...

PHOTOSYNTHETIC RESPONSES OF VALLISNERIA AMERICANA FOLLOWING EXPOSURE TO ATRAZINE AT THREE NUTRIENT REGIMES

EPA Science Inventory

The effects of anthropogenic contaminants on Gulf of Mexico plant communities are poorly understood despite the threatened condition of a number of seagrass communities and wetland habitats. In this study, we focused particular attention on the concern that elevated nutrient
l...

The Psychophysiological Mechanisms of Alexithymia in Autism Spectrum Disorder

ERIC Educational Resources Information Center

Gaigg, Sebastian B.; Cornell, Anna S. F.; Bird, Geoffrey

2018-01-01

Accumulating evidence indicates that co-occurring alexithymia underlies several facets of the social-emotional difficulties common in individuals with autism spectrum disorder. The mechanisms involved, however, remain poorly understood because measuring alexithymia relies heavily on self-report. To address this issue, carefully matched groups of…

Sugary beverage intake and preclinical Alzheimer's disease in the community

USDA-ARS?s Scientific Manuscript database

IMPORTANCE: Sugary beverages are a key component of the Western diet, yet the long-term effects of these beverages on the brain are poorly understood. OBJECTIVE: To determine whether habitual sugary beverage consumption is associated with markers of preclinical Alzheimers disease (AD) and/or vascu...

Spread and development of Phytophthora ramorum in a California christmas tree farm

Treesearch

Gary A. Chastagner; Kathy Riley; Norm Dart

2008-01-01

The risk of conifers being infected by Phytophthora ramorum under natural conditions is poorly understood. In California, infected conifers commonly occur as understory plants beneath or adjacent to heavily infected plants like California bay laurel (Umbellularia californica). During wet periods, P. ramorum is...

Satellite observation of particulate organic carbon dynamics on the Louisiana continental shelf

EPA Science Inventory

Particulate organic carbon (POC) plays an important role in coastal carbon cycling and the formation of hypoxia. Yet, coastal POC dynamics are often poorly understood due to a lack of long-term POC observations and the complexity of coastal hydrodynamic and biogeochemical process...

HYDRAULIC REDISTRIBUTION IN A DOUGLAS-FIR FOREST: LESSONS FROM SYSTEM MANIPULATIONS

EPA Science Inventory

Hydraulic redistribution (HR) has been shown to slow drying of surface soils during drought in Pacific Northwest forests, but the controls governing this process and its importance to shallow-rooted species are poorly understood. Our objective in this study was to manipulate the...

Identification of a Pathway for Perfluorocompounds to Human Diet from Application of Biosolids to Agricultural Fields

EPA Science Inventory

Perfluoro compounds are ubiquitous contaminants in human blood. The pathways which result in near universal exposure to humans in modern societies are not clearly understood. Sources to environmental compartments and transport between compartments are only poorly studies, and thi...

Glucose supplementation has minimal effects on blood neutrophil functionand gene expression in vitro

USDA-ARS?s Scientific Manuscript database

During early lactation, glucose availability is low and the effect of glucose supply on bovine polymorphonuclear leukocyte (PMNL) function is poorly understood. The objective of this study was to determine the effect of glucose supplementation on the function and transcriptomic inflammatory respons...

The water balance components of undisturbed tropical woodlands in the Brazilian cerrado

USDA-ARS?s Scientific Manuscript database

Deforestation of the Brazilian cerrado region has caused major changes in hydrological processes. These changes in water balance components are still poorly understood but are important for making land management decisions in this region. To better understand pre-deforestation conditions, we determi...

Soil type and species diversity influence selection on physiology in Panicum virgatum

USDA-ARS?s Scientific Manuscript database

Species diversity influences the productivity and stability of plant communities, but its effect on the evolution of species within those communities is poorly understood. In this study, we tested whether species diversity and soil type influence selection on physiology in switchgrass (Panicum virga...

Mechanisms of increased lifespan in hypoxia in the alfalfa leafcutting bee, Megachile rotundata

USDA-ARS?s Scientific Manuscript database

Genetic variation accounts for a small amount of variation in lifespan, while environmental stressors are strong predictors. Hypoxia is an environmental stress that increases longevity in some contexts, but the mechanisms remain poorly understood. In the bee Megachile rotundata, lifespan doubles upo...

Spatial variability in the structure of intertidal crab and gastropod assemblages within the Seychelles Archipelago (Indian Ocean)

NASA Astrophysics Data System (ADS)

Smale, Dan A.; Barnes, David K. A.; Barnes, Richard S. K.; Smith, David J.; Suggett, David J.

2012-04-01

Tropical nearshore ecosystems represent global hotspots of marine biodiversity and endemism but are often poorly understood and impacted by human activities. The Seychelles Archipelago (Western Indian Ocean) sustains a wealth of marine life, much of which is threatened by rapid development associated with tourism and climate change. Six marine parks exist within the Archipelago, but their biodiversity value and ecological health are poorly known, especially with regards to non-fish and coral species. Here we investigate spatial patterns of littoral biodiversity on 6 islands, 5 of which were granitic and within marine parks, including the first surveys of Curieuse and Ile Cocos. Our surveys formed a nested sampling design, to facilitate an examination of variability in species richness, faunal abundance, taxonomic distinctness and assemblage composition at multiple spatial scales, from islands (> 100 s km) to quadrats (metres). We identified (mostly to species) and enumerated two target taxa, brachyuran decapod crustaceans and gastropod molluscs, and recorded over 8300 individuals belonging to over 150 species. Crabs and gastropods exhibited different patterns of spatial variability, as crab assemblages were generally more distinct between islands, while gastropod assemblages were markedly variable at the smallest spatial scales of 'patch' and 'quadrat'. Intertidal biodiversity was greatest on Curieuse Island and least at Desroches, the latter was being the only coral atoll we surveyed and thereby differing in its geological and ecological context. We discuss likely drivers of these biodiversity patterns and highlight urgently-needed research directions. Our assessment of the status of poorly-known invertebrate assemblages across the Seychelles will complement more extensive surveys of coral and fish assemblages and, in doing so, provide a useful baseline for monitoring the effects of key stressors in the region, such as coastal development and climate change.

Cryotolerance of stallion spermatozoa is related to ROS production and mitochondrial membrane potential rather than to the integrity of sperm nucleus.

PubMed

Yeste, M; Estrada, E; Rocha, L G; Marín, H; Rodríguez-Gil, J E; Miró, J

2015-03-01

Although cryopreservation of stallion spermatozoa allows long-term preservation of spermatozoa from particular stallions and facilitates international trade, it is understood to inflict damages on sperm cells that may finally reduce their fertilizing ability. In addition, individual differences are known to exist in the sperm ability to withstand freeze-thawing protocols. To date, these differences have mainly been reported on the basis of sperm motility and membrane integrity. For this reason, the present work sought to determine differences between good (good freezability ejaculates: GFE) and poor (poor freezability ejaculates: PFE) freezability stallion ejaculates in other sperm parameters, including peroxide and superoxide levels, potential of mitochondrial membrane and nuclear integrity. With this purpose, a total of 24 stallion ejaculates were cryopreserved and classified into two groups (GFE vs. PFE), depending on their sperm membrane integrity and motility after freeze-thawing. From the total of 24 ejaculates, 13 were classified as GFE and the other 11 were classified as PFE. Apart from differences in sperm membrane permeability and lipid disorder after freeze-thawing, GFE presented significantly (p < 0.05) higher percentages of viable spermatozoa with high content of peroxides and of superoxides than PFE. In contrast, and despite cryopreservation of stallion spermatozoa increasing DNA fragmentation and disrupting disulphide bonds in sperm head proteins, no significant differences between GFE and PFE were seen. We can thus conclude that good and poor freezability stallion ejaculates differ in their reactive oxygen species levels after cryopreservation, but not in the damage extent on sperm nucleus. © 2014 American Society of Andrology and European Academy of Andrology.

Evidence synthesis and its role in evidence-based health care.

PubMed

Pearson, Alan

2014-12-01

The central role of evidence synthesis (or the systematic review of evidence) in evidence-based health care is often poorly understood. There are numerous examples in the literature of poorly conceived and/or executed systematic reviews and of a lack of awareness of the international standards developed by the international leaders in systematic reviews. The Cochrane Collaboration has played a critical global role in developing and refining systematic review methods in relation to evidence of effects and of diagnostic accuracy. Copyright © 2014 Elsevier Inc. All rights reserved.

Expanding Spatial and Temporal Coverage of Arctic CH4 and CO2 Fluxes

NASA Astrophysics Data System (ADS)

Murphy, P.; Oechel, W. C.; Moreaux, V.; Losacco, S.; Zona, D.

2013-12-01

Carbon storage and exchange in Arctic ecosystems is the subject of intensive study focused on determining rates, controls, and mechanisms of CH4 and CO2 fluxes. The Arctic contains more than 1 Gt of Carbon in the upper meter of soil, both in the active layer and permafrost (Schuur et al., 2008; Tarnocai et al., 2009). However, the annual pattern and controls on the release of CH4 is inadequately understood in Arctic tundra ecosystems. Annual methane budgets are poorly understood, and very few studies measure fluxes through the freeze-up cycle during autumn months (Mastepanov et al., 2008; Mastepanov et al., 2010; Sturtevant et al., 2012). There is no known, relatively continuous, CH4 flux record for the Arctic. Clearly, the datasets that currently exist for budget calculations and model parameterization and verification are inadequate. This is likely due to the difficult nature of flux measurements in the Arctic. In September 2012, we initiated a research project towards continuous methane flux measurements along a latitudinal transect in Northern Alaska. The eddy-covariance (EC) technique is challenging in such extreme weather conditions due to the effects of ice formation and precipitation on instrumentation, including gas analyzers and sonic anemometers. The challenge is greater in remote areas of the Arctic, when low power availability and limited communication can lead to delays in data retrieval or data loss. For these reasons, a combination of open- and closed-path gas analyzers, and several sonic anemometers (including one with heating), have been installed on EC towers to allow for cross-comparison and cross-referencing of calculated fluxes. Newer instruments for fast CH4 flux determination include: the Los Gatos Research Fast Greenhouse Gas Analyzer and the Li-Cor LI-7700. We also included the self-heated Metek Class-A uSonic-3 Anemometer as a new instrument. Previously existing instruments used for comparison include the Li-Cor LI-7500; Li-Cor LI-7200; Gill WindmasterPro; Gill R3; Campbell Scientific CSAT-3, and METEK USA-1. To prevent gaps in data due to poor weather, we developed a temperature control system to allow de-icing of the sonic instrument based on data quality. Enclosures were also created to support equipment that was not designed for outdoor use. A similar temperature control system was implemented to maintain stable conditions in the enclosures. Five existing EC towers on the north slope of Alaska, in Barrow, Atqasuk, and Ivotuk, are used to obtain CH4 and CO2 fluxes, and allow a comparison of fluxes across sensor type and design. Here we present the instrument set-up and some of the preliminary eddy covariance CH4 and CO2 flux data, which might prove very useful as guidelines for further flux measurements in northern high latitudes.

Reduction of rainbow trout spleen size by splenectomy does not alter resistance against bacterial cold water disease

USDA-ARS?s Scientific Manuscript database

In lower vertebrates, the contribution of the spleen to anti-bacterial immunity is poorly understood. Researchers have previously reported a phenotypic and genetic correlation between resistance to Flavobacterium psychrophilum, the causative agent of bacterial cold water disease (BCWD) and spleen so...

A sprinkling experiment to quantify celerity-velocity differences at the hillslope scale

EPA Science Inventory

The difference between celerity and velocity of hillslope water flow is poorly understood. We assessed these differences by combining a 24-day hillslope sprinkling experiment with a spatially explicit hydrologic model analysis. We focused our work at Watershed 10 at the H.J. And...

Impaired Associative Taste Learning and Abnormal Brain Activation in Kinase-Defective eEF2K Mice

ERIC Educational Resources Information Center

Gildish, Iness; Manor, David; David, Orit; Sharma, Vijendra; Williams, David; Agarwala, Usha; Wang, Xuemin; Kenney, Justin W.; Proud, Chris G.; Rosenblum, Kobi

2012-01-01

Memory consolidation is defined temporally based on pharmacological interventions such as inhibitors of mRNA translation (molecular consolidation) or post-acquisition deactivation of specific brain regions (systems level consolidation). However, the relationship between molecular and systems consolidation are poorly understood. Molecular…

METABOLISM OF PBDES IN FATHEAD MINNOWS (PIMEPHALES PROMELAS) AND EFFECTS ON THYROID REGULATION

EPA Science Inventory

PBDE effects on fish and other wildlife continue to be poorly understood, and this research will contribute to filling this data gap. It will increase our understanding of PBDE metabolic pathways and mechanisms of thyroid dysfunction in fish exposed to this important class of ...

Students' Perspective into the Apathy and Social Disconnectedness They Feel in Undergraduate Business Classrooms

ERIC Educational Resources Information Center

Sashittal, Hemant C.; Jassawalla, Avan R.; Markulis, Peter

2012-01-01

Apathy and social disconnectedness among undergraduate business students remain poorly understood and under-researched--despite evidence that they produce an adverse impact on learning-related outcomes. Qualitative research was initially conducted among a sample of undergraduate business students to identify the antecedents and learning-related…

Fishing for Features

ScienceCinema

Heredia-Langner, Alejandro; Cort, John; Bailey, Vanessa

2018-01-16

The Fishing for Features Signature Discovery project developed a framework for discovering signature features in challenging environments involving large and complex data sets or where phenomena may be poorly characterized or understood. Researchers at PNNL have applied the framework to the optimization of biofuels blending and to discover signatures of climate change on microbial soil communities.

INFILTRATION THROUGH DISTURBED URBAN SOILS AND COMPOST-AMENDED SOIL EFFECTS OF RUNOFF QUALITY AND QUANTITY

EPA Science Inventory

This project examined a common, but poorly understood, problem associated with land development, namely the modifications made to soil structure and the associated reduced rainfall infiltration and increased runoff. The project was divided into two separate major tasks: 1) to tes...

Engineering Education as a Complex System

ERIC Educational Resources Information Center

Gattie, David K.; Kellam, Nadia N.; Schramski, John R.; Walther, Joachim

2011-01-01

This paper presents a theoretical basis for cultivating engineering education as a complex system that will prepare students to think critically and make decisions with regard to poorly understood, ill-structured issues. Integral to this theoretical basis is a solution space construct developed and presented as a benchmark for evaluating…

Can Near-Peer Teaching Improve Academic Performance?

ERIC Educational Resources Information Center

Williams, Brett; Fowler, James

2014-01-01

Near peer teaching is becoming increasingly popular within healthcare education. The experiences and effects of near-peer teaching upon the near-peer teachers' academic performance are poorly understood. In order to address this, the objective of this study was to examine whether a near-peer teaching program improved the overall clinical unit…

Stages and Spatial Scales of Recruitment Limitation in Southern Appalachain Forests

Treesearch

James S. Clark; Eric Macklin; Leslie Wood

1998-01-01

Recruitment limitation of tree population dynamics is poorly understood, because fecundity and dispersal are difficult to characterize in closed stands. We present an approach that estimates seed production and dispersal under closed canopies and four limitations on recruitment: tree density and location, fecundity, seed dispersal, and establishment. Consistent...

Genetic structure and domestication of carrot (Daucus carota subsp. sativus L.) (Apiaceae)

USDA-ARS?s Scientific Manuscript database

Analyses of genetic structure and phylogenetic relationships illuminate the origin and domestication of modern crops. Despite being an important world-wide vegetable, the genetic structure and domestication of carrot (Daucus carota L.) is poorly understood. We provide the first such study using a la...

Emotional climate and feeding styles: observational analysis of dinner in low-income families

USDA-ARS?s Scientific Manuscript database

Indulgent feeding styles have been associated with a higher risk for childhood overweight. The processes through which feeding styles impact child weight are poorly understood. The aim of this study was to observe differences in the emotional climate created by parents (affect, tone of voice, gest...

A small cysteine-rich protein from the Asian soybean rust fungus, Phakopsora pachyrhizi, suppresses plant immunity

USDA-ARS?s Scientific Manuscript database

The Asian soybean rust fungus, Phakopsora pachyrhizi, is an obligate pathogen capable of causing explosive disease epidemics that drastically reduce the yield of soybean (Glycine max). Currently, the molecular mechanisms by which P. pachyrhizi and other rust fungi cause disease are poorly understood...

Developing Research Relationships toward a Learning Partnership

ERIC Educational Resources Information Center

Kaasila, Raimo; Lutovac, Sonja

2015-01-01

Research relationships are often poorly understood. Why are some collaborations between research partners more productive than others? This question was a starting point of this paper. By describing their own experiences over a period of three years, the authors evaluated research relationships through collaborative self-study. At the beginning,…

Reciprocal Peer Coaching: A Critical Contributor to Implementing Individual Leadership Plans

ERIC Educational Resources Information Center

Goldman, Ellen; Wesner, Marilyn; Karnchanomai, Ornpawee

2013-01-01

Billions of dollars are spent annually on programs to develop organizational leaders, yet the effectiveness of these programs is poorly understood. Scholars advise that value is enhanced by the development of individual leadership plans at program completion, followed by implementation experience with subsequent coaching and reflection. The…

BEL1-LIKE HOMEODOMAIN 11 regulated chloroplast development and chlorophyll synthesis in tomato fruit

USDA-ARS?s Scientific Manuscript database

Chloroplast development and chlorophyll content and metabolism in unripe tomato contribute to the growth and development of the fruit, and also the ripe fruit quality, but the mechanism is poorly understood. In this work, seven homeobox-containing transcription factors (TFs) with specific ripening-a...

Geographic variation in mycangial communities of Xyleborus glabratus

USDA-ARS?s Scientific Manuscript database

Abstract Factors that influence fungal communities in ambrosia beetle mycangia are poorly understood. The beetle that is responsible for spreading laurel wilt in the SE USA, Xyleborus glabratus, was examined at three sites along a 500 km N-S transect in Florida, each populated by host trees in the ...

Effects of Post-Encoding Stress on Performance in the DRM False Memory Paradigm

ERIC Educational Resources Information Center

Pardilla-Delgado, Enmanuelle; Alger, Sara E.; Cunningham, Tony J.; Kinealy, Brian; Payne, Jessica D.

2016-01-01

Numerous studies have investigated how stress impacts veridical memory, but how stress influences false memory formation remains poorly understood. In order to target memory consolidation specifically, a psychosocial stress (TSST) or control manipulation was administered following encoding of 15 neutral, semantically related word lists (DRM false…

ROOT GROWTH AND TURNOVER IN DIFFERENT AGED PONDEROSA PINE STANDS IN OREGON, USA

EPA Science Inventory

The impacts of pollution and climate change on soil carbon dynamics are poorly understood, in part due to a lack of information regarding root production and turnover in natural ecosystems. In order to examine how root dynamics change with stand age in ponderosa pine forests (...

Critical role for CCAAT/Enhancer-binding protein beta in immune complex-induced acute lung injury

USDA-ARS?s Scientific Manuscript database

Although inflammation plays a central role in the pathogenesis of acute lung injury (ALI), the molecular mechanisms underlying inflammatory responses in ALI are poorly understood, and therapeutic options remain limited. The CCAAT/enhancer-binding protein (C/EBP) gamma and -gamma have been implicated...

Starvation Promotes Odor/Feeding-Time Associations in Flies

ERIC Educational Resources Information Center

Chouhan, Nitin Singh; Wolf, Reinard; Heisenberg, Martin

2017-01-01

Starvation causes a motivational state that facilitates diverse behaviors such as feeding, walking, and search. Starved "Drosophila" can form odor/feeding-time associations but the role of starvation in encoding of "time" is poorly understood. Here we show that the extent of starvation is correlated with the fly's ability to…

Cobalt Distribution and Speciation: Effect of Aging, Intermittent Submergence, In situ Rice Roots

EPA Science Inventory

The speciation and distribution of cobalt (Co) in soils is poorly understood. This study was conducted using X-ray absorption spectroscopy (XAS) techniques to examine the influence of soluble Co(II) aging, submergence-dried cycling, and the presence of in vivo rice roots on the...

What makes Great Basin sagebrush ecosystems invasible by Bromus tectorum?

Treesearch

Jeanne C. Chambers; Bruce A. Roundy; Robert R. Blank; Susan E. Meyer; A. Whittaker

2007-01-01

Ecosystem susceptibility to invasion by nonnative species is poorly understood, but evidence is increasing that spatial and temporal variability in resources has large-scale effects. We conducted a study in Artemisia tridentata ecosystems at two Great Basin locations examining differences in resource availability and invasibility of Bromus...

Associations among plasma metabolite levels and short-term exposure to PM2.5 and ozone in a cardiac catheterization cohort.

EPA Science Inventory

RATIONALE: Exposure to ambient particulate matter (PM) and ozone has been associated with cardiovascular disease (CVD). However, the mechanisms linking PM and ozone exposure to CVD remain poorly understood .OBJECTIVE: This study explored associations between short-term exposures ...

Accessing and Selecting Word Meaning in Autism Spectrum Disorder

ERIC Educational Resources Information Center

Henderson, L. M.; Clarke, P. J.; Snowling, M. J.

2011-01-01

Background: Comprehension difficulties are commonly reported in autism spectrum disorder (ASD) but the causes of these difficulties are poorly understood. This study investigates how children with ASD access and select meanings of ambiguous words to test four hypotheses regarding the nature of their comprehension difficulties: semantic deficit,…

Effort versus reward: preparing samples for fungal community characterization in high-throughput sequencing surveys of soils

USDA-ARS?s Scientific Manuscript database

Next generation fungal amplicon sequencing is being used with increasing frequency to study fungal diversity in various ecosystems; however, the influence of sample preparation on the characterization of fungal community is poorly understood. We investigated the effects of four procedural modificati...

Size matters: The contribution of mega-infauna to the food webs and ecosystem services of an Oregon estuary - 9-30-12

EPA Science Inventory

Large-bodied invertebrates (bivalves, polychaetes, burrowing shrimps) are common to infaunal communities of NE Pacific estuaries, but their contribution to estuarine community structure, function and ecosystem services is poorly understood because they are difficult to sample and...

Coping Mediates the Association between Gender and Depressive Symptomatology in Adolescence

ERIC Educational Resources Information Center

Malooly, Ashley M.; Flannery, Kaitlin M.; Ohannessian, Christine McCauley

2017-01-01

Previous studies have found evidence for gender and racial/ethnic differences in depressive symptoms in adolescence; however, the mechanisms driving this relationship are poorly understood. The goal of this study was to examine the role of individual differences in dispositional coping in the relationships between gender and depressive…

Cotton defense induction patterns under spatially, temporally and quantitatively varying herbivory levels

USDA-ARS?s Scientific Manuscript database

The optimal defense theory (ODT) predicts that plants allocate defense compounds to their tissues depending on its value and the likelihood of herbivore attack. Whereas ODT has been confirmed for static damage levels it remains poorly understood if ODT holds true for defense organization of inducibl...

Drought and leaf herbivory influence floral volatiles and pollinator attraction

Treesearch

Laura A. Burkle; Justin B. Runyon

2016-01-01

The effects of climate change on species interactions are poorly understood. Investigating the mechanisms by which species interactions may shift under altered environmental conditions will help form a more predictive understanding of such shifts. In particular, components of climate change have the potential to strongly influence floral volatile organic...

CARRY-OVER EFFECTS OF OZONE ON ROOT GROWTH AND CARBOHYDRATE CONCENTRATIONS OF PONDEROSA PINE SEEDLINGS

EPA Science Inventory

Ozone exposure decreases belowground carbon allocation and root growth of plants;however,the extent to which these effects persist and the cumulative impact of ozone stress on plant growth are poorly understood.To evaluate the potential for plant compensation,we followed the prog...

Exposure for ultrafine carbon particles at levels below detectable pulmonary inflammation affects cardiovascular performance in spontaneously hypertensive rats*

EPA Science Inventory

Rationale: Exposure to particulate matter is a risk factor for cardiopulmonary disease but the related molecular mechanisms are poorly understood. Previously we studied cardiovascular responses in healthy WKY rats following inhalation exposure to ultrafine carbon particles (UfCPs...

Relationship of neuropeptide FF receptors with pubertal maturation of gilts

USDA-ARS?s Scientific Manuscript database

Mechanisms governing the timing of puberty in pigs are poorly understood. A genome-wide association study for age at first estrus in pigs identified candidate genes including NPFFR2, which is a putative receptor for RFamide-related peptides (RFRP). RFRP has been shown to negatively regulate secret...

Development of Sensitivity to Audiovisual Temporal Asynchrony during Midchildhood

ERIC Educational Resources Information Center

Kaganovich, Natalya

2016-01-01

Temporal proximity is one of the key factors determining whether events in different modalities are integrated into a unified percept. Sensitivity to audiovisual temporal asynchrony has been studied in adults in great detail. However, how such sensitivity matures during childhood is poorly understood. We examined perception of audiovisual temporal…

Understanding Authority in Classrooms: A Review of Theory, Ideology, and Research

ERIC Educational Resources Information Center

Pace, Judith L.; Hemmings, Annette

2007-01-01

Authority is a fundamental, problematic, and poorly understood component of classroom life. A better understanding of classroom authority can be achieved by reviewing writings on social theory, educational ideology, and qualitative research in schools. Social theories provide important analytical tools for examining the constitutive elements of…

Impacts of feral horse use on riparian vegetation within the sagebrush steppe

USDA-ARS?s Scientific Manuscript database

Feral horses inhabit rangeland ecosystems around the world, but their impacts on riparian ecosystems are poorly understood. We characterized impacts of a free-ranging horse population on the structure and composition of riparian plant communities in the sagebrush steppe ecosystem in the western US....

PERCHLOROETHYLENE (PERC) INHIBITS FUNCTION OF VOLTAGE-GATED CALCIUM CHANNELS IN PHEOCHROMOCYTOMA CELLS.

EPA Science Inventory

The industrial solvent perchloroethylene (PERC) is listed as a hazardous air pollutant in the 1990 Ammendments to Clean Air Act and is a known neurotoxicant. However, the mechanisms by which PERC alters nervous system function are poorly understood. In recent years, it has been d...

RNAi-mediated down-regulation of a melanin polyketide synthase (pks1) gene in the fungus Slafractonia leguminicola

USDA-ARS?s Scientific Manuscript database

The fungus Slafractonia leguminicola, the causal agent of blackpatch disease of legumes produces two mycotoxins slaframine and swainsonine, causing slobbers’ symptoms and locoism of grazing animals, respectively. The genetics of this important fungus is poorly understood. This work aimed to develop ...

Fishing for Features

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

Heredia-Langner, Alejandro; Cort, John; Bailey, Vanessa

2016-07-21

The Fishing for Features Signature Discovery project developed a framework for discovering signature features in challenging environments involving large and complex data sets or where phenomena may be poorly characterized or understood. Researchers at PNNL have applied the framework to the optimization of biofuels blending and to discover signatures of climate change on microbial soil communities.

Tiered Pricing: Implications for Library Collections

ERIC Educational Resources Information Center

Hahn, Karla

2005-01-01

In recent years an increasing number of publishers have adopted tiered pricing of journals. The design and implications of tiered-pricing models, however, are poorly understood. Tiered pricing can be modeled using several variables. A survey of current tiered-pricing models documents the range of key variables used. A sensitivity analysis…

Feeding Patterns and Emotional Care in Breastfed Infants

ERIC Educational Resources Information Center

Smith, Julie P.; Ellwood, Mark

2011-01-01

A number of studies have suggested breastfed infants have improved bonding and attachment or cognitive development outcomes. However, mechanisms by which these differences might develop are poorly understood. We used maternal time use data to examine whether exclusively breastfeeding mothers spend more time in close interactive behaviors with…

AGING AND LIFE-STAGE SUSCEPTIBILITY: TOLUENE EFFECTS ON BRAIN OXIDATIVE STRESS PARAMETERS IN BROWN NORWAY RATS.

EPA Science Inventory

The influence of aging on susceptibility to environmental contaminants is poorly understood. The objectives of this study were to test whether oxidative stress (OS) is a potential toxicity pathway following toluene exposure and to determine if these effects are age-dependent. We ...

Altered belowground carbon cycling following land use change to perennial bioenergy crops

USDA-ARS?s Scientific Manuscript database

Belowground carbon (C) dynamics of terrestrial ecosystems play an important role in the global C cycle and thereby in climate regulation, yet remain poorly understood. Globally, land use change is a major driver of changes in belowground C storage; in general, land clearing and tillage for agricult...

Measuring and Inducing Brain Plasticity in Chronic Aphasia

ERIC Educational Resources Information Center

Fridriksson, Julius

2011-01-01

Brain plasticity associated with anomia recovery in aphasia is poorly understood. Here, I review four recent studies from my lab that focused on brain modulation associated with long-term anomia outcome, its behavioral treatment, and the use of transcranial brain stimulation to enhance anomia treatment success in individuals with chronic aphasia…

Adaptation of neuronal signaling and cell stress response pathways in a multigenic response of Drosophila melanogaster to DDT selection

USDA-ARS?s Scientific Manuscript database

The adaptation of insect populations to insecticidal control is a continual threat human health and sustainable agriculture practices, but many complex genomic mechanisms involved remain poorly understood. A systems approach was applied to investigate the interconnections between structural and func...

Life cycle expression analysis of three cell wall degradation-related genes in ethylene-treated grass

USDA-ARS?s Scientific Manuscript database

Ethylene regulates multiple developmental processes during a plant life cycle, but the effect of ethylene on the upregulation of senescence-, stress-, and post-harvest-related genes in forage grasses is poorly understood. In this work, we used quantitative PCR to determine whether ethylene applicat...

Deficit irrigation practices may alter Vitis vinifera L. resistance to cold injury: Empirical evidence from the field

USDA-ARS?s Scientific Manuscript database

Deficit irrigation reduces seasonal carbohydrate supply and decreases starch concentrations in vegetative tissues. The specific role of starch metabolism in conferring tolerance to cold is still poorly understood. A decrease in cold tolerance after sequential years of deficit irrigation would limit ...

Prevalence of obesity: A public health problem poorly understood

USDA-ARS?s Scientific Manuscript database

This review article discusses the Dietary Guidelines for Americans in support of a total diet approach to achieving diet and health goals, especially as they relate to the obesity epidemic. However, some scientists and organizations have identified one food, food group, or nutrient as the cause of t...

A Qualitative Approach to Understanding Audience's Perceptions of Creativity in Online Advertising

ERIC Educational Resources Information Center

McStay, Andrew

2010-01-01

In this paper I seek to inquire upon audience's perceptions of creativity in online advertising--a heretofore poorly understood area. This paper initially outlines current academic understanding of creativity in online advertising, mainly derived from quantitative assessments. It then advances a qualitative methodology including diary-interviews…

Secondary organic aerosol formation from fossil fuel sources contribute majority of summertime organic mass at Bakersfield

EPA Science Inventory

Secondary organic aerosols (SOA), known to form in the atmosphere from oxidation of volatile organic compounds (VOCs) emitted by anthropogenic and biogenic sources, are a poorly understood but substantial component of atmospheric particles. In this study, we examined the chemic...

Structuring Program Analysis for Educational Research.

ERIC Educational Resources Information Center

Levine, Donald M.

Education is too complex, multidimensional, and poorly understood to lend itself to a single cost/effectiveness criterion. Rather, analysts in the educational field seek to rank alternatives by their effectiveness, report separately on the cost implications, and leave the tradeoffs to the decisionmaker's judgment. In this context, a program is any…

Inhibition in Dot Comparison Tasks

ERIC Educational Resources Information Center

Clayton, Sarah; Gilmore, Camilla

2015-01-01

Dot comparison tasks are commonly used to index an individual's Approximate Number System (ANS) acuity, but the cognitive processes involved in completing these tasks are poorly understood. Here, we investigated how factors including numerosity ratio, set size and visual cues influence task performance. Forty-four children aged 7-9 years completed…

Social Attribution Processes and Comorbid Psychiatric Symptoms in Children with Asperger Syndrome

ERIC Educational Resources Information Center

Meyer, Jessica A.; Mundy, Peter C.; Van Hecke, Amy Vaughan; Durocher, Jennifer Stella

2006-01-01

The factors that place children with Asperger syndrome at risk for comorbid psychiatric symptoms, such as anxiety and depression, remain poorly understood. We investigated the possibility that the children's emotional and behavioral difficulties are associated with social information and attribution processing. Participants were children with…

What Is Lexical Proficiency? Some Answers from Computational Models of Speech Data

ERIC Educational Resources Information Center

Crossley, Scott A.; Salsbury, Tom; McNamara, Danielle S.; Jarvis, Scott

2011-01-01

Lexical proficiency, as a cognitive construct, is poorly understood. However, lexical proficiency is an important element of language proficiency and fluency, especially for second language (L2) learners. Lexical proficiency is also an important attribute of L2 academic achievement. Generally speaking, lexical proficiency comprises breadth of…

Exposure to pairs of Aeromonas strains enhances virulence in the Caenorhabditis elegans infection model

USDA-ARS?s Scientific Manuscript database

Aeromonad virulence remains poorly understood, and is difficult to predict from strain characteristics. In addition, infections are often polymicrobial (i.e., are mixed infections), and 5 -10% of such infections include two distinct aeromonads, which has an unknown impact on virulence. In this work,...

Rehabilitation Counseling Professional Associations: Membership, Membership Intentions, and Levels of Commitment among Rehabilitation Counseling Professionals

ERIC Educational Resources Information Center

Phillips, Brian N.

2011-01-01

Declining membership is a concerning, yet poorly understood issue affecting professional associations across many disciplines (Bauman, 2008). The discipline of rehabilitation counseling is experiencing membership decline even as the number of certified rehabilitation counselors continues to increase (Leahy, 2009). Little empirical research…

Contributions of hydrology to Vesicular Stomatitis Virus emergence in the Western United States

USDA-ARS?s Scientific Manuscript database

Relationships between environmental variables associated with the spread of vector-borne pathogens, such as RNA viruses transmitted to humans and animals, remain poorly understood. Vesicular stomatitis (VS) is caused by a vector-borne, zoonotic RNA virus (VSV), and is the most common vesicular dise...

Statistical Word Learning in Children with Autism Spectrum Disorder and Specific Language Impairment

ERIC Educational Resources Information Center

Haebig, Eileen; Saffran, Jenny R.; Ellis Weismer, Susan

2017-01-01

Background: Word learning is an important component of language development that influences child outcomes across multiple domains. Despite the importance of word knowledge, word-learning mechanisms are poorly understood in children with specific language impairment (SLI) and children with autism spectrum disorder (ASD). This study examined…

The role of CAX1 and CAX3 in elemental distribution and abundance in Arabidopsis seed

USDA-ARS?s Scientific Manuscript database

The ability to alter nutrient partitioning within plant cells is poorly understood. In Arabidopsis (Arabidopsis thaliana), a family of endomembrane cation exchangers (CAXs) transports Ca(2+) and other cations. However, experiments have not focused on how the distribution and partitioning of calcium ...

An Investigation of Factors Involved When Educational Psychologists sSupervise Other Professionals

ERIC Educational Resources Information Center

Callicott, Katie; Leadbetter, Jane

2013-01-01

Inter-professional supervision combines the social processes of supervision and multi-agency working: both complex and often poorly understood processes. This paper discusses the first author's research of inter-professional supervision, involving an educational psychologist (EP) supervising another professional and complements the recently…

Madrone duff and the natural regeneration of Douglas-fir.

Treesearch

Don Minore

1987-01-01

Excellent natural regeneration of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) often occurs under canopies of Pacific madrone (Arbutus menziesii Pursh), but the effects of madrone duff on regeneration are poorly understood. A field experiment was conducted in a thinned Douglas-fir stand in southwestern Oregon to see if...

Storage conditions affecting increase in falling number of soft red winter wheat grain

USDA-ARS?s Scientific Manuscript database

Falling number (FN) of wheat grain, a measure of preharvest sprouting, tends to increase during storage; however, grain and storage conditions that impact FN changes are poorly understood. Wheat grain samples of varying FN from several cultivars were obtained by malting, by incubating wheat stalks,...

Can Human Associated Bacteroides (HF183MGB) be used as a Pathogen Predictor in Urban Watersheds?

EPA Science Inventory

The fate and transport dynamics of fecal indicators and pathogenic microorganisms are poorly characterized in urban watersheds. Moreover, very little is understood about the actual relationship between fecal indicator bacteria (FIB) and the risk to public health. In this study we...

Vegetative biomass predicts inflorescence production along a CO2 concentration gradient in mesic grassland

USDA-ARS?s Scientific Manuscript database

Atmospheric CO2 concentration will likely exceed 500 uL L-1 by 2050, often increasing plant community productivity in part by increasing abundance of species favored by increased CA. Whether increased abundance translates to increased inflorescence production is poorly understood, and is important ...

Homing success in wintering sparrows

Treesearch

C. John Ralph; L. Richard Mewaldt

1976-01-01

The ability of birds to return "home" after displacement is generallywell known but poorly understood because of the multiplicity of variablesthat affect homing performance. These variables can include age andprevious experience of the bird, as well as the timing and distance of thedisplacement. The phenomenon of homing is also difficult to interpretbecause,...

TOXICITY PATHWAY ANALYSIS IN AGING BROWN NORWAY RAT BRAIN FOLLOWING ACUTE TOLUENE EXPOSURE

EPA Science Inventory

The influence of aging on susceptibility to environmental stressors is poorly understood. To investigate the contribution of different life stages on response to toxicants, we examined the effects of acute exposure by oral gavage of the volatile organic solvent toluene (0.00, 0.3...

Short-term Effects of Air Temperature on Blood Markers of Coagulation and Inflammation in Potentially Susceptible Individuals

EPA Science Inventory

Objectives: Changes in air temperature are associated with an increase in cardiovascular events, but the role of pro-coagulant and pro-inflammatory blood markers is still poorly understood. We investigated the association between air temperature and fibrinogen, plasminogen act...

Cardiomyopathy confers susceptibility to particulate matter-induced oxidative stress, vagal dominance, arrhythmia, pulmonary inflammation in heart failure-prone rats

EPA Science Inventory

Acute exposure to ambient fine particulate matter (PM2.5) is tied to cardiovascular morbidity and mortality, especially among those with prior cardiac injury. The mechanisms and pathophysiologic events precipitating these outcomes remain poorly understood but may involve inflamm...

Dysarthria and Friedreich's Ataxia: What Can Intelligibility Assessment Tell Us?

ERIC Educational Resources Information Center

Blaney, Bronagh; Hewlett, Nigel

2007-01-01

Background: Friedreich's ataxia is one of the most common hereditary disorders of the nervous system. Dysarthria is a pervasive symptom of Friedreich's ataxia, yet the clinical presentation of speech symptoms remains poorly understood, leaving clinicians without the evidence required to develop therapy interventions. Aims: The research reported…

Face Scanning Distinguishes Social from Communication Impairments in Autism

ERIC Educational Resources Information Center

Falck-Ytter, Terje; Fernell, Elisabeth; Gillberg, Christopher; Von Hofsten, Claes

2010-01-01

How closely related are the social and communicative impairments in Autism Spectrum Disorder (ASD)? Recent findings in typically developing children suggest that both types of impairment are highly heritable but have only moderate behavioural and genetic overlap. So far, their respective roles in social perception are poorly understood. Here we…

Regulating Approaches to Learning: Testing Learning Strategy Convergences across a Year at University

ERIC Educational Resources Information Center

Fryer, Luke K.; Vermunt, Jan D.

2018-01-01

Background: Contemporary models of student learning within higher education are often inclusive of processing and regulation strategies. Considerable research has examined their use over time and their (person-centred) convergence. The longitudinal stability/variability of learning strategy use, however, is poorly understood, but essential to…

Spatial vegetation patterns and neighborhood competition among woody plants in an East African savanna

USDA-ARS?s Scientific Manuscript database

The majority of research on savanna vegetation dynamics has focused on the coexistence of woody and herbaceous vegetation; interactions among woody plants in savannas are relatively poorly understood. We present data from a 10-year longitudinal study of spatially explicit growth patterns of woody ve...

Variable high pressure processing sensitivities for GII human noroviruses

USDA-ARS?s Scientific Manuscript database

Human norovirus (HuNoV) is the leading cause of foodborne diseases worldwide. High pressure processing (HPP) is one of the most promising non-thermal technologies for decontamination of viral pathogens in foods. However, the survival of HuNoVs by HPP is poorly understood because these viruses cann...

High pressure treatment of human norovirus-like particles: factors affecting destruction efficacy

USDA-ARS?s Scientific Manuscript database

Human norovirus (HuNoV) is the leading cause of foodborne diseases worldwide. High pressure processing (HPP) is considered a promising non-thermal technology to inactivate viral pathogens in foods. However, the effectiveness of HPP on inactivating HuNoV remains poorly understood because it cannot be...

The Reciprocity of "Imitative Learning" through Apprenticeship

ERIC Educational Resources Information Center

Chan, Selena

2017-01-01

Humans are proposed to have evolved to learn through observation, imitation and practice or mimesis. In this article, the contribution of imitation, as an important but poorly understood aspect of mimetic learning, is advocated to create affordances for dyadic learning. However, learning through imitation is often perceived with negative…

The Therapy Process Observational Coding System for Child Psychotherapy Strategies Scale

ERIC Educational Resources Information Center

McLeod, Bryce D.; Weisz, John R.

2010-01-01

Most everyday child and adolescent psychotherapy does not follow manuals that document the procedures. Consequently, usual clinical care has remained poorly understood and rarely studied. The Therapy Process Observational Coding System for Child Psychotherapy-Strategies scale (TPOCS-S) is an observational measure of youth psychotherapy procedures…

High School Dropout in Proximal Context: The Triggering Role of Stressful Life Events

ERIC Educational Resources Information Center

Dupéré, Véronique; Dion, Eric; Leventhal, Tama; Archambault, Isabelle; Crosnoe, Robert; Janosz, Michel

2018-01-01

Adolescents who drop out of high school experience enduring negative consequences across many domains. Yet, the circumstances triggering their departure are poorly understood. This study examined the precipitating role of recent psychosocial stressors by comparing three groups of Canadian high school students (52% boys; M[subscript…

Discrimination and Sleep: The Protective Role of School Belonging

ERIC Educational Resources Information Center

Huynh, Virginia W.; Gillen-O'Neel, Cari

2016-01-01

Ethnic minority adolescents experience certain sleep problems, yet factors that affect their sleep are poorly understood. This study examined the association between ethnic discrimination and sleep during adolescence and the extent to which perceived stress mediated these associations. This study also examined whether school belonging can protect…

Global diversity and geography of soil fungi

Treesearch

Leho Tedersoo; Mohammad Bahram; Sergei Põlme; Urmas Kõljalg; Nourou S. Yorou; Ravi Wijesundera; Luis Villarreal Ruiz; Aida M. Vasco-Palacios; Pham Quang Thu; Ave Suija; Matthew E. Smith; Cathy Sharp; Erki Saluveer; Alessandro Saitta; Miguel Rosas; Taavi Riit; David Ratkowsky; Karin Pritsch; Kadri Põldmaa; Meike Piepenbring; Cherdchai Phosri; Marko Peterson; Kaarin Parts; Kadri Pärtel; Eveli Otsing; Eduardo Nouhra; André L. Njouonkou; R. Henrik Nilsson; Luis N. Morgado; Jordan Mayor; Tom W. May; Luiza Majukim; D. Jean Lodge; Su See Lee; Karl-Henrik Larsson; Petr Kohout; Kentaro Hosaka; Indrek Hiiesalu; Terry W. Henkel; Helery Harend; Liang-dong Guo; Alina Greslebin; Gwen Gretlet; Jozsef Geml; Genevieve Gates; William Dunstan; Chris Dunk; Rein Drenkhan; John Dearnaley; André De Kesel; Tan Dang; Xin Chen; Franz Buegger; Francis Q. Brearley; Gregory Bonito; Sten Anslan; Sandra Abell; Kessy Abarenkov

2014-01-01

Fungi play major roles in ecosystem processes, but the determinants of fungal diversity and biogeographic patterns remain poorly understood. Using DNA metabarcoding data from hundreds of globally distributed soil samples,we demonstrate that fungal richness is decoupled from plant diversity.The plant-to-fungus richness ratio declines exponentially toward the poles....

Climate variability drives population cycling and synchrony

Treesearch

Lars Y. Pomara; Benjamin Zuckerberg

2017-01-01

Aim There is mounting concern that climate change will lead to the collapse of cyclic population dynamics, yet the influence of climate variability on population cycling remains poorly understood. We hypothesized that variability in survival and fecundity, driven by climate variability at different points in the life cycle, scales up from...

Mosquito host choices on livestock amplifiers of Rift Valley fever virus in Kenya

USDA-ARS?s Scientific Manuscript database

Animal hosts may vary in their attraction and acceptability as components of the host location process for assessing biting rates of vectors and risk of exposure to pathogens. However, these parameters remain poorly understood for mosquito vectors of the Rift Valley fever (RVF), an arboviral disease...

Dissecting genome-wide association signals for loss-of-function phenotypes in sorghum flavonoid pigmentation traits

USDA-ARS?s Scientific Manuscript database

Genome-wide association studies (GWAS) are a powerful method to dissect the genetic basis of traits, though in practice the effects of complex genetic architecture and population structure remain poorly understood. To compare mapping strategies we dissect the genetic control of flavonoid pigmentatio...

Is body size important? Seasonal changes in morphology in two grass-feeding Abacarus mites

USDA-ARS?s Scientific Manuscript database

Overwintering strategies in herbivorous mites (Acari: Eriophyoidea) are poorly understood. A study of two Abacarus spp., was conducted to compare body size parameters of adult females in different seasons. Mites of Abacarus n. sp. (under description) and A. lolli were sampled from Bromopsis inermis ...

Single Particulate SEM-EDX Analysis of Iron-Containing Coarse Particulate Matter in an Urban Environment: Sources and Distribution of Iron within Cleveland, Ohio

EPA Science Inventory

The physicochemical properties of coarse-mode, iron-containing particles, and their temporal and spatial distributions are poorly understood. Single particle analysis combining x-ray elemental mapping and computer-controlled scanning electron microscopy (CCSEM-EDX) of passively ...

Modeling Spatial and Temporal Aspects of Visual Backward Masking

ERIC Educational Resources Information Center

Hermens, Frouke; Luksys, Gediminas; Gerstner, Wulfram; Herzog, Michael H.; Ernst, Udo

2008-01-01

Visual backward masking is a versatile tool for understanding principles and limitations of visual information processing in the human brain. However, the mechanisms underlying masking are still poorly understood. In the current contribution, the authors show that a structurally simple mathematical model can explain many spatial and temporal…

Tackling the Difficulties in Learning Evolution: Effects of Adaptive Self-Explanation Prompts

ERIC Educational Resources Information Center

Neubrand, Charlotte; Harms, Ute

2017-01-01

Teaching and learning evolution is challenging. Biology education research shows that the underlying evolutionary concepts are poorly understood among students. This prevents a meaningful understanding of the central biological concepts. The instructional format of self-explanation prompts seems to be promising to respond to these difficulties.…

Environmental enteric dysfunction and growth failure/stunting in global child health

USDA-ARS?s Scientific Manuscript database

Approximately 25% of the world's children aged <5 years have stunted growth, which is associated with increased mortality, cognitive dysfunction, and loss of productivity. Reducing by 40% the number of stunted children is a global target for 2030. The pathogenesis of stunting is poorly understood. P...

Comparative analysis of gut microbiota of Culex restuans (Diptera: Culicidae) females from different parents

USDA-ARS?s Scientific Manuscript database

The potential for gut microbiota to impede or enhance pathogen transmission is well-documented but the factors that shape this microbiota in mosquito vectors are poorly understood. We characterized and compared the gut microbiota of adult females of Culex restuans Theobald from different parents. Cu...

The Role of the Basolateral Amygdala in Punishment

ERIC Educational Resources Information Center

Dit-Bressel, Philip Jean-Richard; McNally, Gavan P.

2015-01-01

Aversive stimuli not only support fear conditioning to their environmental antecedents, they also punish behaviors that cause their occurrence. The amygdala, especially the basolateral nucleus (BLA), has been critically implicated in Pavlovian fear learning but its role in punishment remains poorly understood. Here, we used a within-subjects…

Depression and Relational Health in Asian American and European American College Women

ERIC Educational Resources Information Center

Lund, Terese J.; Chan, Pauline; Liang, Belle

2014-01-01

Research consistently demonstrates elevated rates of depression among college-aged women, yet evidence of racial differences in depression among this population are poorly understood. Moreover, the correlates of depression among Asian American women are also understudied. In this exploratory analysis, we examined mean differences in depression…

Flexibility and extracellular opening determine the interaction between ligands and insect sulfakinin receptors

USDA-ARS?s Scientific Manuscript database

Despite their fundamental importance for growth, the mechanisms that regulate food intake are poorly understood. Our previous work demonstrated that insect sulfakinin (SK) signaling is involved in inhibiting feeding in an important model and pest insect, the red flour beetle Tribolium castaneum. B...

Soy protein isolate inhibits hepatic tumor promotion in mice fed a high-fat liquid diet

USDA-ARS?s Scientific Manuscript database

Alcoholic and nonalcoholic fatty liver disease are risk factors for development of hepatocellular carcinoma, but the underlying mechanisms are poorly understood. On the other hand, ingestion of soy-containing diets may oppose the development of certain cancers. We previously reported that replacing ...

Acute and Subchronic Toxicity of Inhaled Toluene in Male Long-Evans Rats: Oxidative Stress Markers in Brain

EPA Science Inventory

The effects of exposure to volatile organic compounds (VOCs), which are of concern to the EPA, are poorly understood, in part because of insufficient characterization of how human exposure duration impacts VOC effects. Two inhalation studies with multiple endpoints, one acute an...

The Importance of Allochthonous Subsidies to an Estuarine Food Web along a Salinity Gradient

EPA Science Inventory

Estuarine food webs function within a heterogeneous mosaic and are supported by a mix of primary producers from both local and distant sources. Processes governing the exchange and consumption of organic matter (OM), however, are poorly understood. To study the contribution of ...

Metabolic coevolution in the bacterial symbiosis of whiteflies and related plant sap-feeding insects

USDA-ARS?s Scientific Manuscript database

In animals dependent on intracellular bacteria with very small genomes, the host cell is adapted to support the function of its bacterial symbionts, but the molecular basis of these adaptations is poorly understood. We investigated the metabolic coevolution between the whitefly Bemisia tabaci and th...

How Do Teachers View Their Own Pedagogical Authority?

ERIC Educational Resources Information Center

Harjunen, Elina

2009-01-01

Authority, a fundamental part of the teaching-studying-learning process, is a problematic and poorly understood component of classroom life. It can be said, in practical terms, that pedagogical authority is constructed in classrooms, in teacher-student interaction and in the spirit of their physical presence, confidence, appreciation,…

Changes in Markers of Genotoxicity in Relation to Exposure to Disinfection By-Products in Swimming Pools

EPA Science Inventory

Exposure to disinfection by-products (DBPs) has been associated with cancer risk, but the mechanisms of action are poorly understood. A recent study found increased bladder cancer risk among subjects attending swimming pools, where uptake of DBPs, such as trihalomethanes (THMs) c...

Understanding the carotenoid biosynthetic pathway through observation of four color variants of developing watermelon (Citrullus lanatus (Thunb.) Matsum. & Nanai)

USDA-ARS?s Scientific Manuscript database

The carotenoid biosynthetic pathway regulatory mechanisms leading to lycopene accumulation are well defined in the model fruit, tomato (Lycopersicon esculentum L.). The regulatory mechanisms leading to accumulation of other carotenoids and flesh colors, however, are poorly understood. The variety ...

A COMPUTER-CONTROLLED SYSTEM FOR GENERATING UNIFORM SURFACE DEPOSITS TO STUDY THE TRANSPORT OF PARTICULATE MATTER

EPA Science Inventory

Improved methods for measuring and assessing microenvironmental exposure in individuals are needed. How human activities affect particulate matter in the personal cloud is poorly understood. A quality assurance tool to aid the study of particle transport mechanisms (e.g., re-en...

Luminal Starch Substrate "Brake" on Maltase-Glucoamylase Activity Is Located within the Glucoamylase Subunit

USDA-ARS?s Scientific Manuscript database

The detailed mechanistic aspects for the final starch digestion process leading to effective alpha-glucogenesis by the 2 mucosal alpha-glucosidases, human sucrase-isomaltase complex (SI) and human maltase-glucoamylase (MGAM), are poorly understood. This is due to the structural complexity and vast v...

Evidence of a sewer vapor transport pathway at the USEPA vapor intrusion research duplex

EPA Science Inventory

The role of sewer lines as preferential pathways for vapor intrusion is poorly understood. Although the importance of sewer lines for volatile organic compound (VOC) transport has been documented at a small number of sites with vapor intrusion, sewer lines are not routinely sampl...

Variations in Cognitive Maps: Understanding Individual Differences in Navigation

ERIC Educational Resources Information Center

Weisberg, Steven M.; Schinazi, Victor R.; Newcombe, Nora S.; Shipley, Thomas F.; Epstein, Russell A.

2014-01-01

There are marked individual differences in the formation of cognitive maps both in the real world and in virtual environments (VE; e.g., Blajenkova, Motes, & Kozhevnikov, 2005; Chai & Jacobs, 2010; Ishikawa & Montello, 2006; Wen, Ishikawa, & Sato, 2011). These differences, however, are poorly understood and can be difficult to…

Synergism between inositol polyphosphates and TOR kinase signaling in nutrient sensing, growth control, and lipid metabolism in Chlamydomonas

USDA-ARS?s Scientific Manuscript database

The networks that govern carbon metabolism and control intracellular carbon partitioning in photosynthetic cells are poorly understood. Target of rapamycin (TOR) kinase is a conserved growth regulator that integrates nutrient signals and modulates cell growth in eukaryotes, though the TOR signaling ...

Altered White Matter Microstructure in Adolescents with Major Depression: A Preliminary Study

ERIC Educational Resources Information Center

Cullen, Kathryn R.; Klimes-Dougan, Bonnie; Muetzel, Ryan; Mueller, Bryon A.; Camchong, Jazmin; Houri, Alaa; Kurma, Sanjiv; Lim, Kelvin O.

2010-01-01

Objective: Major depressive disorder (MDD) occurs frequently in adolescents, but the neurobiology of depression in youth is poorly understood. Structural neuroimaging studies in both adult and pediatric populations have implicated frontolimbic neural networks in the pathophysiology of MDD. Diffusion tensor imaging (DTI), which measures white…

EFFECTS OF TOLUENE ON BRAIN OXIDATIVE STRESS PARAMETERS IN AGING BROWN NORWAY RATS

EPA Science Inventory

Aging-related susceptibility to environmental chemicals is poorly understood. Oxidative stress (OS) appears to play an important role in susceptibility and disease in old age. The objectives of this study, therefore, were to test whether OS is a potential toxicity pathway for tol...

Social Motor Synchronization: Insights for Understanding Social Behavior in Autism

ERIC Educational Resources Information Center

Fitzpatrick, Paula; Romero, Veronica; Amaral, Joseph L.; Duncan, Amie; Barnard, Holly; Richardson, Michael J.; Schmidt, R. C.

2017-01-01

Impairments in social interaction and communication are critical features of ASD but the underlying processes are poorly understood. An under-explored area is the social motor synchronization that happens when we coordinate our bodies with others. Here, we explored the relationships between dynamical measures of social motor synchronization and…

NEIGHBORHOODS AND COMMUNITY INVOLVEMENT: NO MICROBE IS AN ISLAND

EPA Science Inventory

The most important thing which must be understood about microorganisms in their environments is that no microbe exists by itself. We should consider that in the environment no microbe is an island existing independently. There are only a few, extremely rare, instances when a sing...

The effects of caffeine on the cholinergic system.

PubMed

Pohanka, Miroslav

2014-01-01

Caffeine is a secondary metabolite of tea and coffee plants. It is the active psychostimulant ingredient of widely consumed beverages, chocolate and some drugs as well. The major pathways for caffeine including interaction with adenosine receptors have been identified but caffeine has several minor pathways as well that remain poorly understood including the cholinergic system. Given the role of caffeine in the cholinergic system, some molecular targets have been tracked and a mechanism of its action has been proposed in research studies. However, the biological effect of caffeine on the cholinergic system is not completely understood. The present review focuses on the role of caffeine in the cholinergic system.

If and when: intrinsic differences and environmental stressors influence migration in brown trout (Salmo trutta).

PubMed

Peiman, Kathryn S; Birnie-Gauvin, Kim; Midwood, Jonathan D; Larsen, Martin H; Wilson, Alexander D M; Aarestrup, Kim; Cooke, Steven J

2017-06-01

Partial migration is a common phenomenon, yet the causes of individual differences in migratory propensity are not well understood. We examined factors that potentially influence timing of migration and migratory propensity in a wild population of juvenile brown trout (Salmo trutta) by combining experimental manipulations with passive integrated transponder telemetry. Individuals were subjected to one of six manipulations: three designed to mimic natural stressors (temperature increase, food deprivation, and chase by a simulated predator), an injection of exogenous cortisol designed to mimic an extreme physiological challenge, a sham injection, and a control group. By measuring length and mass of 923 individuals prior to manipulation and by monitoring tagged individuals as they left the stream months later, we assessed whether pre-existing differences influenced migratory tendency and timing of migration, and whether our manipulations affected growth, condition, and timing of migration. We found that pre-existing differences predicted migration, with smaller individuals and individuals in poor condition having a higher propensity to migrate. Exogenous cortisol manipulation had the largest negative effect on growth and condition, and resulted in an earlier migration date. Additionally, low-growth individuals within the temperature and food deprivation treatments migrated earlier. By demonstrating that both pre-existing differences in organism state and additional stressors can affect whether and when individuals migrate, we highlight the importance of understanding individual differences in partial migration. These effects may carry over to influence migration success and affect the evolutionary dynamics of sub-populations experiencing different levels of stress, which is particularly relevant in a changing world.

Defining pyromes and global syndromes of fire regimes.

PubMed

Archibald, Sally; Lehmann, Caroline E R; Gómez-Dans, Jose L; Bradstock, Ross A

2013-04-16

Fire is a ubiquitous component of the Earth system that is poorly understood. To date, a global-scale understanding of fire is largely limited to the annual extent of burning as detected by satellites. This is problematic because fire is multidimensional, and focus on a single metric belies its complexity and importance within the Earth system. To address this, we identified five key characteristics of fire regimes--size, frequency, intensity, season, and extent--and combined new and existing global datasets to represent each. We assessed how these global fire regime characteristics are related to patterns of climate, vegetation (biomes), and human activity. Cross-correlations demonstrate that only certain combinations of fire characteristics are possible, reflecting fundamental constraints in the types of fire regimes that can exist. A Bayesian clustering algorithm identified five global syndromes of fire regimes, or pyromes. Four pyromes represent distinctions between crown, litter, and grass-fueled fires, and the relationship of these to biomes and climate are not deterministic. Pyromes were partially discriminated on the basis of available moisture and rainfall seasonality. Human impacts also affected pyromes and are globally apparent as the driver of a fifth and unique pyrome that represents human-engineered modifications to fire characteristics. Differing biomes and climates may be represented within the same pyrome, implying that pathways of change in future fire regimes in response to changes in climate and human activity may be difficult to predict.

Access to pain treatment as a human right

PubMed Central

2010-01-01

Background Almost five decades ago, governments around the world adopted the 1961 Single Convention on Narcotic Drugs which, in addition to addressing the control of illicit narcotics, obligated countries to work towards universal access to the narcotic drugs necessary to alleviate pain and suffering. Yet, despite the existence of inexpensive and effective pain relief medicines, tens of millions of people around the world continue to suffer from moderate to severe pain each year without treatment. Discussion Significant barriers to effective pain treatment include: the failure of many governments to put in place functioning drug supply systems; the failure to enact policies on pain treatment and palliative care; poor training of healthcare workers; the existence of unnecessarily restrictive drug control regulations and practices; fear among healthcare workers of legal sanctions for legitimate medical practice; and the inflated cost of pain treatment. These barriers can be understood not only as a failure to provide essential medicines and relieve suffering but also as human rights abuses. Summary According to international human rights law, countries have to provide pain treatment medications as part of their core obligations under the right to health; failure to take reasonable steps to ensure that people who suffer pain have access to adequate pain treatment may result in the violation of the obligation to protect against cruel, inhuman and degrading treatment. PMID:20089155

Collecting the Missing Piece of the Puzzle: The Wind Temperatures of Arcturus (K2 III) and Aldeberan (K5 III)

NASA Astrophysics Data System (ADS)

Harper, Graham

2017-08-01

Unravelling the poorly understood processes that drive mass loss from red giant stars requires that we empirically constrain the intimately coupled momentum and energy balance. Hubble high spectral resolution observations of wind scattered line profiles, from neutral and singly ionized species, have provided measures of wind acceleration, turbulence, terminal speeds, and mass-loss rates. These wind properties inform us about the force-momentum balance, however, the spectra have not yielded measures of the much needed wind temperatures, which constrain the energy balance.We proposed to remedy this omission with STIS E140H observations of the Si III 1206 Ang. resonance emission line for two of the best studied red giants: Arcturus (alpha Boo: K2 III) and Aldebaran (alpha Tau: K5 III), both of which have detailed semi-empirical wind velocity models. The relative optical depths of wind scattered absorption in Si III 1206 Ang., O I 1303 Ang. triplet., C II 1335 Ang., and existing Mg II h & k and Fe II profiles give the wind temperatures through the thermally controlled ionization balance. The new temperature constraints will be used to test existing semi-empirical models by comparision with multi-frequency JVLA radio fluxes, and also to constrain the flux-tube geometry and wave energy spectrum of magnetic wave-driven winds.

Defining pyromes and global syndromes of fire regimes

PubMed Central

Archibald, Sally; Lehmann, Caroline E. R.; Gómez-Dans, Jose L.; Bradstock, Ross A.

2013-01-01

Fire is a ubiquitous component of the Earth system that is poorly understood. To date, a global-scale understanding of fire is largely limited to the annual extent of burning as detected by satellites. This is problematic because fire is multidimensional, and focus on a single metric belies its complexity and importance within the Earth system. To address this, we identified five key characteristics of fire regimes—size, frequency, intensity, season, and extent—and combined new and existing global datasets to represent each. We assessed how these global fire regime characteristics are related to patterns of climate, vegetation (biomes), and human activity. Cross-correlations demonstrate that only certain combinations of fire characteristics are possible, reflecting fundamental constraints in the types of fire regimes that can exist. A Bayesian clustering algorithm identified five global syndromes of fire regimes, or pyromes. Four pyromes represent distinctions between crown, litter, and grass-fueled fires, and the relationship of these to biomes and climate are not deterministic. Pyromes were partially discriminated on the basis of available moisture and rainfall seasonality. Human impacts also affected pyromes and are globally apparent as the driver of a fifth and unique pyrome that represents human-engineered modifications to fire characteristics. Differing biomes and climates may be represented within the same pyrome, implying that pathways of change in future fire regimes in response to changes in climate and human activity may be difficult to predict. PMID:23559374

A Resolution to the Blue Whiting (Micromesistius poutassou) Population Paradox?

PubMed Central

Pointin, Fabien; Payne, Mark R.

2014-01-01

We provide the strongest evidence to date supporting the existence of two independent blue whiting (Micromesistius poutassou (Risso, 1827)) populations in the North Atlantic. In spite of extensive data collected in conjunction with the fishery, the population structure of blue whiting is poorly understood. On one hand, genetic, morphometric, otolith and drift modelling studies point towards the existence of two populations, but, on the other hand, observations of adult distributions point towards a single population. A paradox therefore arises in attempting to reconcile these two sets of information. Here we analyse 1100 observations of blue whiting larvae from the Continuous Plankton Recorder (CPR) from 1948–2005 using modern statistical techniques. We show a clear spatial separation between a northern spawning area, in the Rockall Trough, and a southern one, off the Porcupine Seabight. We further show a difference in the timing of spawning between these sites of at least a month, and meaningful differences in interannual variability. The results therefore support the two-population hypothesis. Furthermore, we resolve the paradox by showing that the acoustic observations cited in support of the single-population model are not capable of resolving both populations, as they occur too late in the year and do not extend sufficiently far south to cover the southern population: the confusion is the result of a simple observational artefact. We conclude that blue whiting in the North Atlantic comprises two populations. PMID:25184302

The development of principled connections and kind representations.

PubMed

Haward, Paul; Wagner, Laura; Carey, Susan; Prasada, Sandeep

2018-07-01

Kind representations draw an important distinction between properties that are understood as existing in instances of a kind by virtue of their being the kind of thing they are and properties that are not understood in this manner. For example, the property of barking for the kind dog is understood as being had by dogs by virtue of the fact that they are dogs. These properties are said to have a principled connection to the kind. In contrast, the property of wearing a collar is not understood as existing in instances by virtue of their being dogs, despite the fact that a large percentage of dogs wear collars. Such properties are said to have a statistical connection to the kind. Two experiments tested two signatures of principled connections in 4-7 year olds and adults: (i) that principled connections license normative expectations (e.g., we judge there to be something wrong with a dog that does not bark), and (ii) that principled connections license formal explanations which explain the existence of a property by reference to the kind (e.g., that barks because it is a dog). Experiment 1 showed that both the children and adults have normative expectations for properties that have a principled connection to a kind, but not those that have a mere statistical connection to a kind. Experiment 2 showed that both children and adults are more likely to provide a formal explanation when explaining the existence of properties with a principled connection to a kind than properties with statistical connections to their kinds. Both experiments showed no effect of age (over ages 4, 7, and adulthood) on the extent to which participants differentiated principled and statistical connections. We discuss the implications of the results for theories of conceptual representation and for the structure of explanation. Copyright © 2018 Elsevier B.V. All rights reserved.

Nutrient adequacy and diet quality in low-income Hispanic Children – The VIVA LA FAMILIA Study

USDA-ARS?s Scientific Manuscript database

The role of nutrient adequacy and diet quality in the etiology of childhood obesity is poorly understood. Epidemiological studies have suggested that low-cost, energy dense diets high in grains, added sugars, and fat contribute to the development of obesity, especially in low-income groups. The spec...

Cue-Dependent Interference in Comprehension

ERIC Educational Resources Information Center

Van Dyke, Julie A.; McElree, Brian

2011-01-01

The role of interference as a primary determinant of forgetting in memory has long been accepted, however its role as a contributor to poor comprehension is just beginning to be understood. The current paper reports two studies, in which speed-accuracy tradeoff and eye-tracking methodologies were used with the same materials to provide converging…

Land-use history has a stronger impact on soil microbial community composition than aboveground vegetation and soil properties

USDA-ARS?s Scientific Manuscript database

The response of soil microbial communities following soil disturbances is poorly understood. The development of soil microbial communities in two restoration gradients was studied to investigate the impact of land-management regime at the W. K. Kellogg Biological Station, Michigan. The first restora...

Brainstem Transcription of Speech Is Disrupted in Children with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Russo, Nicole; Nicol, Trent; Trommer, Barbara; Zecker, Steve; Kraus, Nina

2009-01-01

Language impairment is a hallmark of autism spectrum disorders (ASD). The origin of the deficit is poorly understood although deficiencies in auditory processing have been detected in both perception and cortical encoding of speech sounds. Little is known about the processing and transcription of speech sounds at earlier (brainstem) levels or…

The Multiple Subfunctions of Attention: Differential Developmental Gateways to Literacy and Numeracy

ERIC Educational Resources Information Center

Steele, Ann; Karmiloff-Smith, Annette; Cornish, Kim; Scerif, Gaia

2012-01-01

Attention is construed as multicomponential, but the roles of its distinct subfunctions in shaping the broader developing cognitive landscape are poorly understood. The current study assessed 3- to 6-year-olds (N = 83) to: (a) trace developmental trajectories of attentional processes and their structure in early childhood and (b) measure the…

Germination and growth of native and invasive plants on soil associated with biological control of Tamarisk (Tamarix spp.)

USDA-ARS?s Scientific Manuscript database

Introductions of biocontrol beetles (tamarisk beetles) are causing dieback of exotic tamarisk in riparian zones across the western U.S., yet factors that determine plant communities that follow tamarisk dieback are poorly understood. Tamarisk-dominated soils are generally higher in nutrients, organi...

Fasting the Microbiota to Improve Metabolism?

PubMed

Haas, Joel T; Staels, Bart

2017-10-03

While intermittent or periodic fasting provides a variety of favorable health benefits, the molecular mediators of these effects are poorly understood. In this issue of Cell Metabolism, Li and colleagues (2017) highlight the role of gut microbiota in mediating benefits of intermittent fasting through activation of adipose tissue beiging. Copyright © 2017. Published by Elsevier Inc.

Nitrogen cycling following mountain pine beetle disturbance in lodgepole pine forests of Greater Yellowstone

Treesearch

Jacob M. Griffin; Monica G. Turner; Martin Simard

2011-01-01

Widespread bark beetle outbreaks are currently affecting multiple conifer forest types throughout western North America, yet many ecosystem-level consequences of this disturbance are poorly understood. We quantified the effect of mountain pine beetle (Dendroctonus ponderosae) outbreak on nitrogen (N) cycling through litter, soil, and vegetation in...

ANALYTICAL CHEMISTRY RESEARCH NEEDS FOR MAPPING TRENDS OF PHARMACEUTICAL AND PERSONAL CARE PRODUCT POLLUTION FROM PERSONAL USE

EPA Science Inventory

The consensus among environmental scientists and risk assessors is that the fate and effects of pharmaceutical and personal care products (PPCPS) in the environment are poorly understood. Many classes of PPCPs have yet to be investigated. Acquisition of trends data for a suite of...

Length of efficacy for control of curly top in sugar beet with seed foliar insecticides

USDA-ARS?s Scientific Manuscript database

Curly top in sugar beet caused by Beet curly top virus (BCTV) is an important yield limiting disease that can be reduced via neonicotinoid and pyrethroid insecticides. However the length of efficacy of these insecticides is poorly understood, so a series of field experiments was conducted with the ...

Chapter 1: The cactus ferruginous pygmy-owl: Taxonomy, distribution, and natural history

Treesearch

Jean-Luc E. Cartron; W. Scott Richardson; Glenn A. Proudfoot

2000-01-01

The cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) is a small, cryptic owl that is often difficult to observe. Its natural history and conservation needs are poorly understood. Despite ongoing research in Texas and Arizona, the available information remains limited. In addition, factors influencing demographics (e.g., habitat...

Relationship between Nutritional Knowledge and the Amount of Sugar-Sweetened Beverages Consumed in Los Angeles County

ERIC Educational Resources Information Center

Gase, Lauren N.; Robles, Brenda; Barragan, Noel C.; Kuo, Tony

2014-01-01

Although consumption of sugar-sweetened beverages (SSBs) is associated with many negative health outcomes, including obesity, diabetes, and cardiovascular disease, the relationship between consumer nutritional knowledge and the amount consumed is poorly understood. The objective of this study was to examine the relationship between knowledge of…

Understanding of Facial Expressions of Emotion by Children with Intellectual Disabilities of Differing Aetiology

ERIC Educational Resources Information Center

Wishart, J. G.; Cebula, K. R.; Willis, D. S.; Pitcairn, T. K.

2007-01-01

Background: Interpreting emotional expressions is a socio-cognitive skill central to interpersonal interaction. Poor emotion recognition has been reported in autism but is less well understood in other kinds of intellectual disabilities (ID), with procedural differences making comparisons across studies and syndromes difficult. This study aimed to…

Loneliness and Depression among Polish University Students: Preliminary Findings from a Longitudinal Study

ERIC Educational Resources Information Center

Grygiel, Pawel; Switaj, Piotr; Anczewska, Marta; Humenny, Grzegorz; Rebisz, Slawomir; Sikorska, Justyna

2013-01-01

It is widely acknowledged that loneliness and depression are prevalent among university students and may contribute to poor academic achievements or higher probability of dropping out of university. However, the associations between these two phenomena are complex and not fully understood. In this paper we describe preliminary findings from a…

Heritability of Creative Achievement

ERIC Educational Resources Information Center

Piffer, Davide; Hur, Yoon-Mi

2014-01-01

Although creative achievement is a subject of much attention to lay people, the origin of individual differences in creative accomplishments remain poorly understood. This study examined genetic and environmental influences on creative achievement in an adult sample of 338 twins (mean age = 26.3 years; SD = 6.6 years). Twins completed the Creative…

Approaches to understanding the impact of life-history features on plant-pathogen co-evolutionary dynamics

Treesearch

Jeremy J. Burdon; Peter H. Thrall; Adnane Nemri

2012-01-01

Natural plant-pathogen associations are complex interactions in which the interplay of environment, host, and pathogen factors results in spatially heterogeneous ecological and epidemiological dynamics. The evolutionary patterns that result from the interaction of these factors are still relatively poorly understood. Recently, integration of the appropriate spatial and...

Academic Performance of Transfer Versus "Native" Students in Natural Resources & Sciences

ERIC Educational Resources Information Center

Johnson, Matthew D.

2005-01-01

Transfer students comprise a substantial component of the student body in many 4-year academic colleges, but the factors affecting students' success once they have transferred are poorly understood. Using data from standard university records, academic performance was examined for 2,467 students enrolled in natural resource majors at a mid-sized…

AGE-RELATED TOXICITY PATHWAY ANALYSIS IN BROWN NORWAY RAT BRAIN FOLLOWING ACUTE TOLUENE EXPOSURE

EPA Science Inventory

The influence of aging on susceptibility to environmental exposures is poorly understood. To investigate-the contribution of different life stages on response to toxicants, we examined the effects of an acute exposure to the volatile organic compound, toluene (0.0 or 1.0 g/kg), i...

Context Modulates Attention to Social Scenes in Toddlers with Autism

ERIC Educational Resources Information Center

Chawarska, Katarzyna; Macari, Suzanne; Shic, Frederick

2012-01-01

Background: In typical development, the unfolding of social and communicative skills hinges upon the ability to allocate and sustain attention toward people, a skill present moments after birth. Deficits in social attention have been well documented in autism, though the underlying mechanisms are poorly understood. Methods: In order to parse the…

PHYTOTOXICITY OF THREE SUBMERGED AQUATIC MACROPHYTE SPECIES TO COPPER AND ATRAZINE UNDER HIGH AND LOW NUTRIENT CONCENTRATIONS

EPA Science Inventory

The effects of anthropogenic contaminants on Gulf of Mexico plant communities are poorly understood despite the declining number of seagrass communities and wetland habitats. This presentation focuses on the second phase of a multi-year study designed to determine the role of su...

Structure of the mouthparts of Frankliniella bispinosa (Morgan) (Thysanoptera: Thripidae)

Treesearch

Carl C. Childers; Diann S. Achor

1991-01-01

Thrips are increasingly recognized as potentially serious pests in a number of different agricultural, ornamental and sylvan commodities worldwide as indicated by the papers presented at this conference. The small size of thrips, their large numbers, capacity for flight and wind dispersal, wide host ranges, poorly understood life histories and probable potential for...

Paracrine-acting adiponectin promotes mammary epithelial differentiation and synergizes with genistein to enhance transcriptional response to estrogen receptor beta signaling

USDA-ARS?s Scientific Manuscript database

Mammary stromal adipocytes constitute an active site for the synthesis of the adipokine adiponectin (APN) that may influence the mammary epithelial microenvironment. The relationship between 'local', mammary tissue-derived APN and breast cancer risk is poorly understood. Herein, we identify a novel ...

The Impact of Threat of Shock-Induced Anxiety on Memory Encoding and Retrieval

ERIC Educational Resources Information Center

Bolton, Sorcha; Robinson, Oliver J.

2017-01-01

Anxiety disorders are the most common mental health disorders, and daily transient feelings of anxiety (or "stress") are ubiquitous. However, the precise impact of both transient and pathological anxiety on higher-order cognitive functions, including short- and long-term memory, is poorly understood. A clearer understanding of the…

Spatial and temporal controls on watershed ecohydrology in the northern Rocky Mountains

Treesearch

Ryan E. Emanuel; Howard E. Epstein; Brian L. McGlynn; Daniel L. Welsch; Daniel J. Muth; Paulo D& #65533; fOdorico

2010-01-01

Vegetation water stress plays an important role in the movement of water through the soil�]plant�]atmosphere continuum. However, the effects of water stress on evapotranspiration (ET) and other hydrological processes at the watershed scale remain poorly understood due in part to spatially and temporally heterogeneous conditions within the...

Is brood parasitism related to host nestling diet and nutrition?

Treesearch

Zachary S. Ladin; Vincent D' Amico; Deb P. Jaisi; W. Gregory Shriver

2015-01-01

Food and nutrient limitation can have negative effects on survival, fecundity, and lifetime fitness of individuals, which can ultimately limit populations. Changes in trophic dynamics and diet patterns, affected by anthropogenic environmental and landscape change, are poorly understood yet may play an important role in population regulation. We determined diets of Wood...

Identification and characterization of pyrokinin and CAPA peptides, and corresponding GPCRs from spotted wing drosophila, Drosophila suzukii

USDA-ARS?s Scientific Manuscript database

To date, some biological activities have been confirmed as different named peptides, however, most FXPRLamide peptides are still poorly understood although these peptides are found in all insects. So, the study of receptors for these peptides is particularly important. Receptors of FXPRLamide peptid...

Principles of Cancer Screening.

PubMed

Pinsky, Paul F

2015-10-01

Cancer screening has long been an important component of the struggle to reduce the burden of morbidity and mortality from cancer. Notwithstanding this history, many aspects of cancer screening remain poorly understood. This article presents a summary of basic principles of cancer screening that are relevant for researchers, clinicians, and public health officials alike. Published by Elsevier Inc.

Children's Ideas of Animals' Internal Structures

ERIC Educational Resources Information Center

Prokop, Pavol; Prokop, Matej; Tunnicliffe, Sue Dale; Diran, Carla

2007-01-01

Children's understanding about animal internal structure can be affected by several factors which are poorly understood by teachers. We conducted a large sample study (n=702) of children aged 6-16 years (Grades 1-9) examining children's responses to animals of various size, species and dimensions (2D and 3D objects), and exploring factors which…

Depressive Symptoms and Parenting Competence: An Analysis of 13 Regulatory Processes

ERIC Educational Resources Information Center

Dix, Theodore; Meunier, Leah N.

2009-01-01

Mechanisms that lead depressive symptoms to undermine parenting are poorly understood. This review examines cognitive, affective, and motivational processes thought to be responsible for the impact of depressive symptoms on parenting. We present a five-step, action-control model and review 152 studies relevant to 13 regulatory processes. Evidence…

How Does Creating a Concept Map Affect Item-Specific Encoding?

ERIC Educational Resources Information Center

Grimaldi, Phillip J.; Poston, Laurel; Karpicke, Jeffrey D.

2015-01-01

Concept mapping has become a popular learning tool. However, the processes underlying the task are poorly understood. In the present study, we examined the effect of creating a concept map on the processing of item-specific information. In 2 experiments, subjects learned categorized or ad hoc word lists by making pleasantness ratings, sorting…

Invasive perennial grasses in Quercus garryana meadows of southwestern British Columbia: prospects for restoration

Treesearch

Andrew MacDougall

2002-01-01

Garry oak (Quercus garryana) meadows of the Pacific Northwest are heavily invaded but the dynamics surrounding this ecosystem transformation are poorly understood. Of particular uncertainty is the role of the invasive species in structuring the community, and the potential stability of this invasive-dominated system when disturbed. Clarifying such...

The role of mites in insect-fungus associations

Treesearch

R. W. Hofstetter; J. C. Moser

2014-01-01

The interactions among insects, mites, and fungi are diverse and complex but poorly understood in most cases. Associations among insects, mites, and fungi span an almost incomprehensible array of ecological interactions and evolutionary histories. Insects and mites often share habitats and resources and thus interact within communities. Many mites and insects rely on...

Higher Learning, Greater Good: The Private and Social Benefits of Higher Education

ERIC Educational Resources Information Center

McMahon, Walter W.

2009-01-01

A college education has long been acknowledged as essential for both personal success and economic growth. But the measurable value of its nonmonetary benefits has until now been poorly understood. Walter W. McMahon, a leading education economist, carefully describes these benefits and suggests that higher education accrues significant social and…

Genetic Influences on Mechanically-Assessed Activity Level in Children

ERIC Educational Resources Information Center

Wood, Alexis C.; Saudino, Kimberly J.; Rogers, Hannah; Asherson, Philip; Kuntsi, Jonna

2007-01-01

Background: Activity level is an important component of children's temperament, as well as being part of the core symptom domain of hyperactivity-impulsivity within attention deficit hyperactivity disorder (ADHD). Yet it is poorly understood, due partly to limitations on parent and teacher ratings, which are typically used as measurements of these…