Sample records for poorly understood process

  1. 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…

  2. 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…

  3. 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…

  4. 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...

  5. 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,...

  6. 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...

  7. 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…

  8. 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…

  9. 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...

  10. 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…

  11. 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...

  12. 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...

  13. 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…

  14. 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…

  15. Consequences of Contextual Factors on Clinical Reasoning in Resident Physicians

    ERIC Educational Resources Information Center

    McBee, Elexis; Ratcliffe, Temple; Picho, Katherine; Artino, Anthony R., Jr.; Schuwirth, Lambert; Kelly, William; Masel, Jennifer; van der Vleuten, Cees; Durning, Steven J.

    2015-01-01

    Context specificity and the impact that contextual factors have on the complex process of clinical reasoning is poorly understood. Using situated cognition as the theoretical framework, our aim was to evaluate the verbalized clinical reasoning processes of resident physicians in order to describe what impact the presence of contextual factors have…

  16. 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...

  17. 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 (...

  18. Effects of straw processing and pen stocking density on holstein dairy heifers: ii) behavior and hygiene

    USDA-ARS?s Scientific Manuscript database

    The effects of pen-stocking density and straw processing on the daily behavior traits and hygiene of Holstein dairy heifers housed in a freestall system are not understood. Our objective was to evaluate these factors in a trial with a 2 × 3 factorial arrangement of straw-processing (GOOD or POOR) an...

  19. 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...

  20. The Process of Screening Student-Athletes for Cardiovascular Diseases at NCAA Division I Institutions in the Northeast

    ERIC Educational Resources Information Center

    Blizzard, Ronell

    2010-01-01

    Sudden cardiac death among athletes continues to take the lives of college students across the nation. Leadership at all levels of higher education has great concern over this phenomenon. However, the processes and procedures related to hypertrophic cardiomyopathy (HCM) remain poorly understood. Corrado (1998) suggests that sudden cardiac death of…

  1. Cat Got Your Tongue? Using the Tip-of-the-Tongue State to Investigate Fixed Expressions

    ERIC Educational Resources Information Center

    Nordmann, Emily; Cleland, Alexandra A.; Bull, Rebecca

    2013-01-01

    Despite the fact that they play a prominent role in everyday speech, the representation and processing of fixed expressions during language production is poorly understood. Here, we report a study investigating the processes underlying fixed expression production. "Tip-of-the-tongue" (TOT) states were elicited for well-known idioms…

  2. Lexical Processing in School-Age Children with Autism Spectrum Disorder and Children with Specific Language Impairment: The Role of Semantics

    ERIC Educational Resources Information Center

    Haebig, Eileen; Kaushanskaya, Margarita; Weismer, Susan Ellis

    2015-01-01

    Children with autism spectrum disorder (ASD) and specific language impairment (SLI) often have immature lexical-semantic knowledge; however, the organization of lexical-semantic knowledge is poorly understood. This study examined lexical processing in school-age children with ASD, SLI, and typical development, who were matched on receptive…

  3. The importance of tree size and fecundity for wind dispersal of big-leaf mahogany

    Treesearch

    Julian M. Norghauer; Charles A. Nock; James Grogan

    2011-01-01

    Seed dispersal by wind is a critical yet poorly understood process in tropical forest trees. How tree size and fecundity affect this process at the population level remains largely unknown because of insufficient replication across adults. We measured seed dispersal by the endangered neotropical timber species big-leaf mahogany (Swietenia macrophylla King, Meliaceae)...

  4. Lab Astro and the Origins of the Chemical Elements

    NASA Astrophysics Data System (ADS)

    Lawler, James E.

    2010-03-01

    Interpretation of the spectra of metal-poor Galactic halo stars is dependent on AMO laboratory data [1,2]. Metal-poor Galactic halo stars were born when the Milky Way was young and they provide a record of the chemical evolution of the Galaxy. Elements heavier than iron are produced via r(apid)-process and s(low)-process n(eutron)-capture mechanisms. The s-process mechanism, which occurs in certain AGB stars, is relatively well understood. The explosive r-process is not well understood. The r-process n-capture mechanism was dominant early in the Galaxy's history [3]. New large aperture telescopes make it possible to record high-resolution spectra with high signal-to-noise ratios on a growing number of metal-poor stars. In addition to mapping the chemical evolution of the Galaxy, these studies are yielding an increasingly well-defined r-process elemental abundance pattern which constrains models of r-process nucleosynthesis [1]. The next phase of this ongoing research will address challenges in modeling stellar photospheres. Peculiar trends in abundances of specific Fe-group elements as a function of stellar age or metallicity may be due to limitations in traditional one dimensional (1d) local thermodynamic equilibrium (LTE) models of stellar photospheres or may be due to poorly understood nucleosynthesis [4]. Efforts are now underway to test the Saha or ionization equilibrium in a variety of stellar atmospheres for several Fe-group elements using the best available spectroscopic data for selected transitions. More comprehensive spectroscopic data of improved accuracy and accurate collisional data, especially for inelastic collisions of H atoms with metal atoms and ions, will be needed to fully develop 3d/non-LTE models of photospheres [e.g. 5]. [4pt] [1] C. Sneden, J. E. Lawler, J. J. Cowan, I. I. Ivans, and E. A. Den Hartog, Astrophys. J. Suppl. Ser. 182, 80-96 (2009). [0pt] [2] J. E. Lawler, C. Sneden, J. J. Cowan, I. I. Ivans, and E. A. Den Hartog, Astrophys. J. Suppl. Ser. 182, 51-79 (2009). [0pt] [3] J. Simmerer, C. Sneden, J. J. Cowan, J. Collier, V. M. Woolf, and J. E. Lawler, Astrophys. J. 617, 1091-1114 (2004). [0pt] [4] A. McWilliam, Ann. Rev. Astron. & Astrophys. 35, 503 (1997). [0pt] [5] M. Asplund, Ann. Rev. Astron. & Astrophys. 43, 481 (2005).

  5. 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 ...

  6. 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...

  7. 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...

  8. 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 ...

  9. 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…

  10. 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.

  11. Basic Number Processing Deficits in ADHD: A Broad Examination of Elementary and Complex Number Processing Skills in 9- to 12-Year-Old Children with ADHD-C

    ERIC Educational Resources Information Center

    Kaufmann, Liane; Nuerk, Hans-Christoph

    2008-01-01

    ADHD (attention-deficit hyperactivity disorder) and academic difficulties are frequently associated, but to date this link is poorly understood. In order to explore which components of number processing and calculation skills may be disturbed in children with ADHD we presented a series of respective tasks to 9- to 12-year-old children with…

  12. Wounding induces changes in tuber polyamine content, polyamine metabolic gene expression, and enzyme activity during closing layer formation and initiation of wound periderm formation

    USDA-ARS?s Scientific Manuscript database

    Tuber wound-healing processes are complex, and the associated regulation and modulation of these processes are poorly understood. Polyamines (PA) have been shown to be involved in modulating a variety of responses to biotic and abiotic plant stresses and have been suggested to be involved in tuber ...

  13. 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…

  14. 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...

  15. 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...

  16. 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...

  17. A conceptual framework for Lake Michigan coastal/nearshore ecosystems, with application to Lake Michigan Lakewide Management Plan (LaMP) objectives

    USGS Publications Warehouse

    Seelbach, Paul W.; Fogarty, Lisa R.; Bunnell, David Bo; Haack, Sheridan K.; Rogers, Mark W.

    2013-01-01

    The Lakewide Management Plans (LaMPs) within the Great Lakes region are examples of broad-scale, collaborative resource-management efforts that require a sound ecosystems approach. Yet, the LaMP process is lacking a holistic framework that allows these individual actions to be planned and understood within the broader context of the Great Lakes ecosystem. In this paper we (1) introduce a conceptual framework that unifies ideas and language among Great Lakes managers and scientists, whose focus areas range from tributary watersheds to open-lake waters, and (2) illustrate how the framework can be used to outline the geomorphic, hydrologic biological, and societal processes that underlie several goals of the Lake Michigan LaMP, thus providing a holistic and fairly comprehensive roadmap for tackling these challenges. For each selected goal, we developed a matrix that identifies the key ecosystem processes within the cell for each lake zone and each discipline; we then provide one example where a process is poorly understood and a second where a process is understood, but its impact or importance is unclear. Implicit in these objectives was our intention to highlight the importance of the Great Lakes coastal/nearshore zone. Although the coastal/nearshore zone is the important linkage zone between the watershed and open-lake zones—and is the zone where most LaMP issues are focused--scientists and managers have a relatively poor understanding of how the coastal/nearshore zone functions. We envision follow-up steps including (1) collaborative development of a more detailed and more complete conceptual model of how (and where) identified processes are thought to function, and (2) a subsequent gap analysis of science and monitoring priorities.

  18. Appraisal, Coping, and Social Support as Mediators of Well-Being in Black and White Family Caregivers of Patients with Alzheimer's Disease.

    ERIC Educational Resources Information Center

    Haley, William E.; And Others

    1996-01-01

    Family caregivers of patients with Alzheimer's disease (AD) commonly have high levels of psychological distress. Black caregivers often report less depression than white caregivers, but the process underlying this difference is poorly understood. With the use of a stress process model, 123 white and 74 black family caregivers of patients with AD…

  19. 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...

  20. 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...

  1. 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…

  2. 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…

  3. 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...

  4. 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....

  5. 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...

  6. 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…

  7. 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 ...

  8. 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,…

  9. 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...

  10. 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…

  11. 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

  12. 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.

  13. 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.

  14. 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…

  15. 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...

  16. Differential Engagement of Brain Regions within a "Core" Network during Scene Construction

    ERIC Educational Resources Information Center

    Summerfield, Jennifer J.; Hassabis, Demis; Maguire, Eleanor A.

    2010-01-01

    Reliving past events and imagining potential future events engages a well-established "core" network of brain areas. How the brain constructs, or reconstructs, these experiences or scenes has been debated extensively in the literature, but remains poorly understood. Here we designed a novel task to investigate this (re)constructive process by…

  17. A Truth that's Told with Bad Intent: An ERP Study of Deception

    ERIC Educational Resources Information Center

    Carrion, Ricardo E.; Keenan, Julian P.; Sebanz, Natalie

    2010-01-01

    Human social cognition critically relies on the ability to deceive others. However, the cognitive and neural underpinnings of deception are still poorly understood. Why does lying place increased demands on cognitive control? The present study investigated whether cognitive control processes during deception are recruited due to the need to…

  18. Soil microbial responses to elevated CO2 and O3 in a nitrogen-aggrading agroecosystem

    USDA-ARS?s Scientific Manuscript database

    Despite decades of study, the underlying mechanisms by which soil microbes respond to rising atmospheric CO2 and ozone remain poorly understood. A prevailing hypothesis, which states that changes in C availability induced by elevated CO2 and ozone drive alterations in soil microbes and the processe...

  19. Observations and analysis of organic aerosol evolution in some prescribed fire smoke plumes

    Treesearch

    A. A. May; T. Lee; G. R. McMeeking; S. Akagi; A. P. Sullivan; S. Urbanski; R. J. Yokelson; S. M. Kreidenweis

    2015-01-01

    Open biomass burning is a significant source of primary air pollutants such as particulate matter (PM) and non-methane organic gases (NMOG). However, the physical and chemical atmospheric processing of these emissions during transport is poorly understood. Atmospheric transformations of biomass burning emissions have been investigated in environmental chambers, but...

  20. Increasing Conceptual Understanding of Glycolysis & the Krebs Cycle Using Role-Play

    ERIC Educational Resources Information Center

    Ross, Pauline M.; Tronson, Deidre A.; Ritchie, Raymond J.

    2008-01-01

    Cellular respiration and metabolism are topics that are reportedly poorly understood by students and judged to be difficult by many teachers. Although these topics may not be required learning areas in some high school biology curricula, a grasp of fundamental concepts of cellular metabolic processes is advantageous for students undertaking (or…

  1. Dopamine Receptor DOP-4 Modulates Habituation to Repetitive Photoactivation of a "C. elegans" Polymodal Nociceptor

    ERIC Educational Resources Information Center

    Ardiel, Evan L.; Giles, Andrew C.; Yu, Alex J.; Lindsay, Theodore H.; Lockery, Shawn R.; Rankin, Catharine H.

    2016-01-01

    Habituation is a highly conserved phenomenon that remains poorly understood at the molecular level. Invertebrate model systems, like "Caenorhabditis elegans," can be a powerful tool for investigating this fundamental process. Here we established a high-throughput learning assay that used real-time computer vision software for behavioral…

  2. The physiological basis for regeneration response to variable retention harvest treatments in three pine species

    Treesearch

    Matthew D. Powers; Kurt S. Pregitzer; Brian J. Palik; Christopher R. Webster

    2011-01-01

    Variable retention harvesting (VRH) is promoted for enhancing biodiversity and ecosystem processes in managed forests, but regeneration responses to the complex stand structures that result from VRH are poorly understood. We analyzed foliar stable carbon isotope ratios (δ13C), oxygen isotope ratios (δ18O...

  3. The Origin and Significance of the CCAM Line: Evidence from Chondrules and Dark Inclusions in Allende (CV3)

    NASA Technical Reports Server (NTRS)

    Greenwood, R. C.; Franchi, I. A.; Zolensky, M. E.; Buchanan, P. C.

    2016-01-01

    The process responsible for the mass independent oxygen isotope variation observed in Solar System materials remains poorly understood. While self-shielding of CO, either in the early solar nebula, or precursor molecular cloud, appears to be a viable mechanism, alternative models have also been proposed.

  4. Evasion of mucosal defenses during Aeromonas hydrophila infection of channel catfish (Ictalurus punctatus) skin

    USDA-ARS?s Scientific Manuscript database

    The mucosal surfaces of fish serve as the first-line of defense against the myriad of aquatic pathogens present in the aquatic environment. The immune repertoire functioning at these interfaces is still poorly understood. The skin, in particular, must process signals from several fronts, sensing and...

  5. Wounding induces changes in cytokinin and auxin content in potato tuber, but does not induce formation of gibberellins

    USDA-ARS?s Scientific Manuscript database

    Cytokinin, auxin and gibberellin content in resting and wound-responding potato tuber are not clearly defined. Consequently, the coordination and possible networking of these classical hormones in the regulation of wound-healing processes are poorly understood. Using a well-defined tuber wound-hea...

  6. Cognitive Operations on Space and Their Impact on the Precision of Location Memory

    ERIC Educational Resources Information Center

    Lansdale, Mark; Humphries, Joyce; Flynn, Victoria

    2013-01-01

    Learning about object locations in space usually involves the summation of information from different experiences of that space and requires various cognitive operations to make this possible. These processes are poorly understood and, in the extreme, may not occur--leading to mutual exclusivity of memories (Baguley, Lansdale, Lines, & Parkin,…

  7. Relative size and stand age determine Pinus banksiana mortality

    Treesearch

    Han Y. H. Chen; Songling Fu; Robert A. Monserud; Ian C. Gillies

    2008-01-01

    Tree mortality is a poorly understood process in the boreal forest. Whereas large disturbances reset succession by killing all or most trees, background tree mortality was hypothesized to be affected by competition, ageing, and stand composition. We tested these hypotheses on jack pine (Pinus banksiana Lamb.) mortality using data from long-term...

  8. Multi-decadal establishment for single-cohort Douglas-fir forests

    Treesearch

    James A. Freund; Jerry F. Franklin; Andrew J. Larson; James A. Lutz

    2014-01-01

    The rate at which trees regenerate following stand-replacing wildfire is an important but poorly understood process in the multi-century development of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) forests. Temporal patterns of Douglas-fir establishment reconstructed from old-growth forests (>450 year) have...

  9. Age, Cohort and Perceived Age Discrimination: Using the Life Course to Assess Self-Reported Age Discrimination

    ERIC Educational Resources Information Center

    Gee, Gilbert C.; Pavalko, Eliza K.; Long, J. Scott

    2007-01-01

    Self-reported discrimination is linked to diminished well-being, but the processes generating these reports remain poorly understood. Employing the life course perspective, this paper examines the correspondence between expected age preferences for workers and perceived age discrimination among a nationally representative sample of 7,225 working…

  10. Reduced N400 Semantic Priming Effects in Adult Survivors of Paediatric and Adolescent Traumatic Brain Injury

    ERIC Educational Resources Information Center

    Knuepffer, C.; Murdoch, B. E.; Lloyd, D.; Lewis, F. M.; Hinchliffe, F. J.

    2012-01-01

    The immediate and long-term neural correlates of linguistic processing deficits reported following paediatric and adolescent traumatic brain injury (TBI) are poorly understood. Therefore, the current research investigated event-related potentials (ERPs) elicited during a semantic picture-word priming experiment in two groups of highly functioning…

  11. Novelty-Induced Arousal Enhances Memory for Cued Classical Fear Conditioning: Interactions between Peripheral Adrenergic and Brainstem Glutamatergic Systems

    ERIC Educational Resources Information Center

    King, Stanley O., II; Williams, Cedric L.

    2009-01-01

    Exposure to novel contexts produce heightened states of arousal and biochemical changes in the brain to consolidate memory. However, processes permitting simple exposure to unfamiliar contexts to elevate sympathetic output and to improve memory are poorly understood. This shortcoming was addressed by examining how novelty-induced changes in…

  12. Hybrid Sterility over Tens of Meters Between Ecotypes Adapted to Serpentine and Non-Serpentine Soils

    Treesearch

    Leonie Moyle; Levine Mia; Stanton Maureen; Jessica Wright

    2012-01-01

    The development of hybrid sterility is an important step in the process of speciation, however the role of adaptive evolution in triggering these postzygotic barriers is poorly understood. We show that, in the California endemic plant Collinsia sparsiflora ecotypic adaptation to two distinct soil types is associated with the expression of...

  13. Stable water isotopes suggest sub-canopy water recycling in a northern forested catchment

    Treesearch

    Mark B. Green; Bethany K. Laursen; John L. Campbell; Kevin J. McGuire; Eric P. Kelsey

    2015-01-01

    Stable water isotopes provide a means of tracing many hydrologic processes, including poorly understood dynamics like soil water interactions with the atmosphere. We present a four-year dataset of biweekly water isotope samples from eight fluxes and stores in a headwater catchment at the Hubbard Brook Experimental Forest, New Hampshire, USA. We use Dansgaard's...

  14. The Therapeutic Alliance and Family Psychoeducation in the Treatment of Schizophrenia: An Exploratory Prospective Change Process Study

    ERIC Educational Resources Information Center

    Smerud, Phyllis E.; Rosenfarb, Irwin S.

    2008-01-01

    Although family psychoeducation has been shown to be highly efficacious in the treatment of schizophrenia, the mechanisms underlying the treatment's success are poorly understood. The therapeutic alliance in behavioral family management (BFM) was examined to determine whether the alliance plays a role in the efficacy of this treatment. One early…

  15. Role of Dentate Gyrus in Aligning Internal Spatial Map to External Landmark

    ERIC Educational Resources Information Center

    Lee, Jong Won; Kim, Woon Ryoung; Sun, Woong; Jung, Min Whan

    2009-01-01

    Humans and animals form internal representations of external space based on their own body movement (dead reckoning) as well as external landmarks. It is poorly understood, however, how different types of information are integrated to form a unified representation of external space. To examine the role of dentate gyrus (DG) in this process, we…

  16. Yohimbine Impairs Extinction of Cocaine-Conditioned Place Preference in an [alpha] [subscript 2]-Adrenergic Receptor Independent Process

    ERIC Educational Resources Information Center

    Davis, Adeola R.; Shields, Angela D.; Brigman, Jonathan L.; Norcross, Maxine; McElligott, Zoe A.; Holmes, Andrew; Winder, Danny G.

    2008-01-01

    Extinction, a form of learning that has the ability to reshape learned behavior based on new experiences, has been heavily studied utilizing fear learning paradigms. Mechanisms underlying extinction of positive-valence associations, such as drug self-administration and place preference, are poorly understood yet may have important relevance to…

  17. Candidate Electrophysiological Endophenotypes of Hyper-Reactivity to Change in Autism

    ERIC Educational Resources Information Center

    Gomot, Marie; Blanc, Romuald; Clery, Helen; Roux, Sylvie; Barthelemy, Catherine; Bruneau, Nicole

    2011-01-01

    Although resistance to change is a main feature of autism, the brain processes underlying this aspect of the disorder remain poorly understood. The aims of this study were to examine neural basis of auditory change-detection in children with autism spectrum disorders (ASD; N = 27) through electrophysiological patterns (MMN, P3a) and to test…

  18. A gnotobiotic pig model for determining human norovirus inactivation by high-pressure processing

    USDA-ARS?s Scientific Manuscript database

    Human norovirus (NoV) is responsible for over 90 percent of outbreaks of acute nonbacterial gastroenteritis worldwide, and accounts for 60 percent of foodborne illness in the US. Currently, the infectivity of human NoVs is poorly understood due to the lack of a cell culture system. In this study, w...

  19. The Political Economy of Alternative Trade: Social and Environmental Certification in the South African Wine Industry

    ERIC Educational Resources Information Center

    McEwan, Cheryl; Bek, David

    2009-01-01

    Despite recent critical analyses of the nature and impacts of social and environmental certification, the increasingly complex landscape of voluntary, industry and third-party codes and certification processes that have emerged in specific sectors is poorly understood. In particular, little is known about the potential threats posed by an…

  20. Mechanisms of Reference Frame Selection in Spatial Term Use: Computational and Empirical Studies

    ERIC Educational Resources Information Center

    Schultheis, Holger; Carlson, Laura A.

    2017-01-01

    Previous studies have shown that multiple reference frames are available and compete for selection during the use of spatial terms such as "above." However, the mechanisms that underlie the selection process are poorly understood. In the current paper we present two experiments and a comparison of three computational models of selection…

  1. Evaluating ecological monitoring of civic environmental stewardship in the Green-Duwamish watershed, Washington

    Treesearch

    Jacob C. Sheppard; Clare M. Ryan; Dale J. Blahna

    2017-01-01

    The ecological outcomes of civic environmental stewardship are poorly understood, especially at scales larger than individual sites. In this study we characterized civic environmental stewardship programs in the Green-Duwamish watershed in King County, WA, and evaluated the extent to which stewardship outcomes were monitored. We developed a four-step process based on...

  2. Embryonic ring closure: Actomyosin rings do the two-step

    PubMed Central

    2016-01-01

    Actomyosin rings drive numerous closure processes, but the mechanisms by which they contract are still poorly understood. In this issue, Xue and Sokac (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201608025) show that actomyosin ring closure during Drosophila melanogaster cellularization uses two steps, only one of which involves Myosin-2. PMID:27799371

  3. Social attribution processes and comorbid psychiatric symptoms in children with Asperger syndrome

    PubMed Central

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

    2009-01-01

    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 either Asperger syndrome (n = 31) or typical development (n = 33).To assess social information and attribution processing, children responded to hypothetical social vignettes.They also completed self-report measures of social difficulties and psychological functioning. Their parents provided information on social competence and clinical presentation. Children with Asperger syndrome showed poor psychosocial adjustment, which was related to their social information and attribution processing patterns. Cognitive and social-cognitive abilities were associated with aspects of social information processing tendencies, but not with emotional and behavioral difficulties. Results suggest that the comorbid symptoms of children with Asperger syndrome may be associated with their social perception, understanding, and experience. PMID:16908481

  4. Anomalous Resistance Hysteresis in Oxide ReRAM: Oxygen Evolution and Reincorporation Revealed by In Situ TEM.

    PubMed

    Cooper, David; Baeumer, Christoph; Bernier, Nicolas; Marchewka, Astrid; La Torre, Camilla; Dunin-Borkowski, Rafal E; Menzel, Stephan; Waser, Rainer; Dittmann, Regina

    2017-06-01

    The control and rational design of redox-based memristive devices, which are highly attractive candidates for next-generation nonvolatile memory and logic applications, is complicated by competing and poorly understood switching mechanisms, which can result in two coexisting resistance hystereses that have opposite voltage polarity. These competing processes can be defined as regular and anomalous resistive switching. Despite significant characterization efforts, the complex nanoscale redox processes that drive anomalous resistive switching and their implications for current transport remain poorly understood. Here, lateral and vertical mapping of O vacancy concentrations is used during the operation of such devices in situ in an aberration corrected transmission electron microscope to explain the anomalous switching mechanism. It is found that an increase (decrease) in the overall O vacancy concentration within the device after positive (negative) biasing of the Schottky-type electrode is associated with the electrocatalytic release and reincorporation of oxygen at the electrode/oxide interface and is responsible for the resistance change. This fundamental insight presents a novel perspective on resistive switching processes and opens up new technological opportunities for the implementation of memristive devices, as anomalous switching can now be suppressed selectively or used deliberately to achieve the desirable so-called deep Reset. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. A STELLA model to estimate water and nitrogen dynamics in a short-rotation woody crop plantation

    Treesearch

    Ying Ouyang; Jiaen Zhang; Theodor D. Leininger; Brent R. Frey

    2015-01-01

    Although short-rotation woody crop biomass production technology has demonstrated a promising potential to supply feedstocks for bioenergy production, the water and nutrient processes in the woody crop planation ecosystem are poorly understood. In this study, a computer model was developed to estimate the dynamics of water and nitrogen (N) species (e.g., NH4...

  6. How Does Schooling of Mothers Improve Child Health? Evidence from Morocco. Living Standards Measurement Study Working Paper No. 128.

    ERIC Educational Resources Information Center

    Glewwe, Paul

    Mothers' education is frequently found to be positively correlated with child health and nutrition in developing countries, and yet the causal mechanisms are poorly understood. An examination was conducted of the role played by three mechanisms in this process: formal education that directly teaches health knowledge to future mothers; literacy and…

  7. Locus of Control Fails to Mediate between Stress and Anxiety and Depression in Parents of Children with a Developmental Disorder

    ERIC Educational Resources Information Center

    Hamlyn-Wright, Sarah; Draghi-Lorenz, Riccardo; Ellis, Jason

    2007-01-01

    Stress, anxiety and depression are raised amongst parents of children with a developmental disorder. However, the processes by which stress leads to depression and anxiety are poorly understood. In a cross-sectional survey, levels of parental stress, depression and anxiety were compared between parents of children with an autistic disorder,…

  8. Long-term effects of fragmentation and fragment properties on bird species richness in Hawaiian forests

    Treesearch

    David J. Flaspohler; Christian P. Giardina; Gregory P. Asner; Patrick Hart; Jonathan Price; Cassie Ka’apu Lyons; Xeronimo Castaneda

    2010-01-01

    Forest fragmentation is a common disturbance affecting biological diversity, yet the impacts of fragmentation on many forest processes remain poorly understood. Forest restoration is likely to be more successful when it proceeds with an understanding of how native and exotic vertebrates utilize forest patches of different size. We used a system of forest fragments...

  9. High-severity fire: Evaluating its key drivers and mapping its probability across western US forests

    Treesearch

    Sean A. Parks; Lisa M. Holsinger; Matthew H. Panunto; W. Matt Jolly; Solomon Z. Dobrowski; Gregory K. Dillon

    2018-01-01

    Wildland fire is a critical process in forests of the western United States (US). Variation in fire behavior, which is heavily influenced by fuel loading, terrain, weather, and vegetation type, leads to heterogeneity in fire severity across landscapes. The relative influence of these factors in driving fire severity, however, is poorly understood. Here, we explore the...

  10. Characteristics of fog and fogwater fluxes in a Puerto Rican elfin cloud forest.

    Treesearch

    Werner Eugster; Reto Burkard; Friso Holwerda; Frederick N. Scatena; L.A.(Sampurno) Bruijnzeel

    2006-01-01

    The Luquillo Mountains of northeastern Puerto Rico harbours important fractions of tropical montane cloud forests. Although it is well known that the frequent occurrence of dense fog is a common climatic characteristic of cloud forests around the world, it is poorly understood how fog processes shape and influence these ecosystems. Our study focuses on the physical...

  11. Psychological Factors Associated with Weight Loss in Obese and Severely Obese Women in a Behavioral Physical Activity Intervention

    ERIC Educational Resources Information Center

    Annesi, James J.; Whitaker, Ann C.

    2010-01-01

    The behavioral processes of weight reduction are poorly understood, and responses to treatments based primarily on caloric restriction have been unfavorable. A theory-based path derived from proposed relations of physical activity, changes in psychological factors, and weight loss was separately tested with women with Class I and Class II obesity…

  12. Factors Influencing the Sahelian Paradox at the Local Watershed Scale: Causal Inference Insights

    NASA Astrophysics Data System (ADS)

    Van Gordon, M.; Groenke, A.; Larsen, L.

    2017-12-01

    While the existence of paradoxical rainfall-runoff and rainfall-groundwater correlations are well established in the West African Sahel, the hydrologic mechanisms involved are poorly understood. In pursuit of mechanistic explanations, we perform a causal inference analysis on hydrologic variables in three watersheds in Benin and Niger. Using an ensemble of techniques, we compute the strength of relationships between observational soil moisture, runoff, precipitation, and temperature data at seasonal and event timescales. Performing analysis over a range of time lags allows dominant time scales to emerge from the relationships between variables. By determining the time scales of hydrologic connectivity over vertical and lateral space, we show differences in the importance of overland and subsurface flow over the course of the rainy season and between watersheds. While previous work on the paradoxical hydrologic behavior in the Sahel focuses on surface processes and infiltration, our results point toward the importance of subsurface flow to rainfall-runoff relationships in these watersheds. The hypotheses generated from our ensemble approach suggest that subsequent explorations of mechanistic hydrologic processes in the region include subsurface flow. Further, this work highlights how an ensemble approach to causal analysis can reveal nuanced relationships between variables even in poorly understood hydrologic systems.

  13. The basics of epithelial-mesenchymal transition.

    PubMed

    Kalluri, Raghu; Weinberg, Robert A

    2009-06-01

    The origins of the mesenchymal cells participating in tissue repair and pathological processes, notably tissue fibrosis, tumor invasiveness, and metastasis, are poorly understood. However, emerging evidence suggests that epithelial-mesenchymal transitions (EMTs) represent one important source of these cells. As we discuss here, processes similar to the EMTs associated with embryo implantation, embryogenesis, and organ development are appropriated and subverted by chronically inflamed tissues and neoplasias. The identification of the signaling pathways that lead to activation of EMT programs during these disease processes is providing new insights into the plasticity of cellular phenotypes and possible therapeutic interventions.

  14. Laboratory tests for mumps vaccines.

    PubMed

    Minor, P D

    1997-03-01

    The action of live attenuated vaccines against mumps is poorly understood although their clinical efficacy is beyond doubt. The attenuated character of the vaccine is assured by consistency of production related to clinical trials, and limited studies of vaccine seeds in primates. Potency is assessed by infectivity in vitro and is subject to poorly understood sources of variation. Molecular biological studies are at an early stage.

  15. Munchausen Syndrome by Proxy: A Clinical Vignette

    PubMed Central

    Zylstra, Robert G.; Miller, Karl E.; Stephens, Walter E.

    2000-01-01

    Munchausen syndrome by proxy is the act of one person fabricating or inducing an illness in another to meet his or her own emotional needs through the treatment process. The diagnosis is poorly understood and controversial. We report here the case of a 6-year-old boy who presented with possible pneumonia, nausea, vomiting, and diarrhea and whose mother was suspected of Munchausen syndrome by proxy. PMID:15014581

  16. Memory Variability Is Due to the Contribution of Recollection and Familiarity, Not to Encoding Variability

    ERIC Educational Resources Information Center

    Koen, Joshua D.; Yonelinas, Andrew P.

    2010-01-01

    It is well established that the memory strength of studied items is more variable than the strength of new items on tests of recognition memory, but the reason why this occurs is poorly understood. One account for this old "item variance effect" is based on single-process theory, which proposes that this effect is due to variability in how well…

  17. Differential Patterns of Abnormal Activity and Connectivity in the Amygdala-Prefrontal Circuitry in Bipolar-I and Bipolar-NOS Youth

    ERIC Educational Resources Information Center

    Ladouceur, Cecile D.; Farchione, Tiffany; Diwadkar, Vaibhav; Pruitt, Patrick; Radwan, Jacqueline; Axelson, David A.; Birmaher, Boris; Phillips, Mary L.

    2011-01-01

    Objective: The functioning of neural systems supporting emotion processing and regulation in youth with bipolar disorder not otherwise specified (BP-NOS) remains poorly understood. We sought to examine patterns of activity and connectivity in youth with BP-NOS relative to youth with bipolar disorder type I (BP-I) and healthy controls (HC). Method:…

  18. Maternal and Paternal Plasma, Salivary, and Urinary Oxytocin and Parent-Infant Synchrony: Considering Stress and Affiliation Components of Human Bonding

    ERIC Educational Resources Information Center

    Feldman, Ruth; Gordon, Ilanit; Zagoory-Sharon, Orna

    2011-01-01

    Studies in mammals have implicated the neuropeptide oxytocin (OT) in processes of bond formation and stress modulation, yet the involvement of OT in human bonding throughout life remains poorly understood. We assessed OT in the plasma, saliva, and urine of 112 mothers and fathers interacting with their 4-6-month-old infants. Parent-infant…

  19. Influences of elevated carbon dioxide and ozone on soil respiration and carbon accumulation in a no-till soybean-wheat system after six years

    USDA-ARS?s Scientific Manuscript database

    Atmospheric carbon dioxide and ozone often have counteracting influences on many C3 crops depending on the concentration of the gases and sensitivity of the crop and variety, but effects of these gases on plant-soil processes are poorly understood. The objective of this six-year experiment was to d...

  20. Grade 3 Learners' Representation of Their Solutions to a Design Problem through Drawing: A Semiotic Analysis

    ERIC Educational Resources Information Center

    Alant, Busisiwe P.; Sherwood, Marion P.

    2017-01-01

    Literature suggests that drawing has an important role in the development of learning and thinking skills and the communication of ideas. However, the role and use of drawing by young learners within the process of designing is poorly understood. Working with 22 Grade 3 learners from a well-resourced school in KwaZulu-Natal, this study sought to…

  1. The Infernal Business of Contract Cheating: Understanding the Business Processes and Models of Academic Custom Writing Sites

    ERIC Educational Resources Information Center

    Ellis, Cath; Zucker, Ian Michael; Randall, David

    2018-01-01

    While there is growing awareness of the existence and activities of Academic Custom Writing websites, which form a small part of the contract cheating industry, how they work remains poorly understood. Very little research has been done on these sites, probably because it has been assumed that it is impossible to see behind their firewalls and…

  2. First steps in studying the origins of secondary woodiness in Begonia (Begoniaceae): combining anatomy, phylogenetics, and stem transcriptomics

    Treesearch

    Catherine Kidner; Andrew Groover; Daniel C. Thomas; Katie Emelianova; Claudia Soliz-Gamboa; Frederic Lens

    2015-01-01

    Since Darwin's observation that secondary woodiness is common on islands, the evolution of woody plants from herbaceous ancestors has been documented in numerous angiosperm groups. However, the evolutionary processes that give rise to this phenomenon are poorly understood. To begin addressing this we have used a range of approaches to study the anatomical and...

  3. Examining the Relationship between Home Literacy Environment and Neural Correlates of Phonological Processing in Beginning Readers with and without a Familial Risk for Dyslexia: An fMRI Study

    ERIC Educational Resources Information Center

    Powers, Sara J.; Wang, Yingying; Beach, Sara D.; Sideridis, Georgios D.; Gaab, Nadine

    2016-01-01

    Developmental dyslexia is a language-based learning disability characterized by persistent difficulty in learning to read. While an understanding of genetic contributions is emerging, the ways the environment affects brain functioning in children with developmental dyslexia are poorly understood. A relationship between the home literacy…

  4. Canopy closure exerts weak controls on understory dynamics: a 30-year study of overstory-understory interactions

    Treesearch

    C.B. Halpern; J.A. Lutz

    2013-01-01

    Stem exclusion and understory reinitiation are commonly described, but poorly understood, stages of forest development. It is assumed that overstory trees exert strong controls on understory herbs and shrubs during the transition from open- to closed-canopy forests, but long-term observations of this process are rare. We use long-term data from 188 plots to explore...

  5. Biodegradation: Updating the concepts of control for microbial cleanup in contaminated aquifers.

    PubMed

    Meckenstock, Rainer U; Elsner, Martin; Griebler, Christian; Lueders, Tillmann; Stumpp, Christine; Aamand, Jens; Agathos, Spiros N; Albrechtsen, Hans-Jørgen; Bastiaens, Leen; Bjerg, Poul L; Boon, Nico; Dejonghe, Winnie; Huang, Wei E; Schmidt, Susanne I; Smolders, Erik; Sørensen, Sebastian R; Springael, Dirk; van Breukelen, Boris M

    2015-06-16

    Biodegradation is one of the most favored and sustainable means of removing organic pollutants from contaminated aquifers but the major steering factors are still surprisingly poorly understood. Growing evidence questions some of the established concepts for control of biodegradation. Here, we critically discuss classical concepts such as the thermodynamic redox zonation, or the use of steady state transport scenarios for assessing biodegradation rates. Furthermore, we discuss if the absence of specific degrader populations can explain poor biodegradation. We propose updated perspectives on the controls of biodegradation in contaminant plumes. These include the plume fringe concept, transport limitations, and transient conditions as currently underestimated processes affecting biodegradation.

  6. Homogenizing and diversifying effects of intensive agricultural land-use on plant species beta diversity in Central Europe - A call to adapt our conservation measures

    Treesearch

    Constanze Buhk; Martin Alt; Manuel J. Steinbauer; Carl Beierkuhnlein; Steve Warren; Anke Jentsch

    2017-01-01

    The prevention of biodiversity loss in agricultural landscapes to protect ecosystem stability and functions is of major importance to stabilize overall diversity. Intense agriculture leads to a loss in species richness and homogenization of species pools, but the processes behind are poorly understood due to a lack of systematic case studies: The specific...

  7. Biocorrosion: towards understanding interactions between biofilms and metals.

    PubMed

    Beech, Iwona B; Sunner, Jan

    2004-06-01

    The term microbially influenced corrosion, or biocorrosion, refers to the accelerated deterioration of metals owing to the presence of biofilms on their surfaces. The detailed mechanisms of biocorrosion are still poorly understood. Recent investigations into biocorrosion have focused on the influence of biomineralization processes taking place on metallic surfaces and the impact of extracellular enzymes, active within the biofilm matrix, on electrochemical reactions at the biofilm-metal interface.

  8. Intense hurricane activity over the past 5,000 years controlled by El Nino and the West African monsoon.

    Treesearch

    Jeffrey P. Donnelly; Jonathan D. Woodruff

    2007-01-01

    The processes that control the formation, intensity and track of hurricanes are poorly understood1. It has been proposed that an increase in sea surface temperatures caused by anthropogenic climate change has led to an increase in the frequency of intense tropical cyclones2,3, but this proposal has been challenged on the basis that the instrumental record is too short...

  9. Alternative splicing in plant immunity.

    PubMed

    Yang, Shengming; Tang, Fang; Zhu, Hongyan

    2014-06-10

    Alternative splicing (AS) occurs widely in plants and can provide the main source of transcriptome and proteome diversity in an organism. AS functions in a range of physiological processes, including plant disease resistance, but its biological roles and functional mechanisms remain poorly understood. Many plant disease resistance (R) genes undergo AS, and several R genes require alternatively spliced transcripts to produce R proteins that can specifically recognize pathogen invasion. In the finely-tuned process of R protein activation, the truncated isoforms generated by AS may participate in plant disease resistance either by suppressing the negative regulation of initiation of immunity, or by directly engaging in effector-triggered signaling. Although emerging research has shown the functional significance of AS in plant biotic stress responses, many aspects of this topic remain to be understood. Several interesting issues surrounding the AS of R genes, especially regarding its functional roles and regulation, will require innovative techniques and additional research to unravel.

  10. Constructing event trees for volcanic crises

    USGS Publications Warehouse

    Newhall, C.; Hoblitt, R.

    2002-01-01

    Event trees are useful frameworks for discussing probabilities of possible outcomes of volcanic unrest. Each branch of the tree leads from a necessary prior event to a more specific outcome, e.g., from an eruption to a pyroclastic flow. Where volcanic processes are poorly understood, probability estimates might be purely empirical - utilizing observations of past and current activity and an assumption that the future will mimic the past or follow a present trend. If processes are better understood, probabilities might be estimated from a theoritical model, either subjectively or by numerical simulations. Use of Bayes' theorem aids in the estimation of how fresh unrest raises (or lowers) the probabilities of eruptions. Use of event trees during volcanic crises can help volcanologists to critically review their analysis of hazard, and help officials and individuals to compare volcanic risks with more familiar risks. Trees also emphasize the inherently probabilistic nature of volcano forecasts, with multiple possible outcomes.

  11. 3D animation model with augmented reality for natural science learning in elementary school

    NASA Astrophysics Data System (ADS)

    Hendajani, F.; Hakim, A.; Lusita, M. D.; Saputra, G. E.; Ramadhana, A. P.

    2018-05-01

    Many opinions from primary school students' on Natural Science are a difficult lesson. Many subjects are not easily understood by students, especially on materials that teach some theories about natural processes. Such as rain process, condensation and many other processes. The difficulty that students experience in understanding it is that students cannot imagine the things that have been taught in the material. Although there is material to practice some theories but is actually quite limited. There is also a video or simulation material in the form of 2D animated images. Understanding concepts in natural science lessons are also poorly understood by students. Natural Science learning media uses 3-dimensional animation models (3D) with augmented reality technology, which offers some visualization of science lessons. This application was created to visualize a process in Natural Science subject matter. The hope of making this application is to improve student's concept. This app is made to run on a personal computer that comes with a webcam with augmented reality. The app will display a 3D animation if the camera can recognize the marker.

  12. Musical Experience, Auditory Perception and Reading-Related Skills in Children

    PubMed Central

    Banai, Karen; Ahissar, Merav

    2013-01-01

    Background The relationships between auditory processing and reading-related skills remain poorly understood despite intensive research. Here we focus on the potential role of musical experience as a confounding factor. Specifically we ask whether the pattern of correlations between auditory and reading related skills differ between children with different amounts of musical experience. Methodology/Principal Findings Third grade children with various degrees of musical experience were tested on a battery of auditory processing and reading related tasks. Very poor auditory thresholds and poor memory skills were abundant only among children with no musical education. In this population, indices of auditory processing (frequency and interval discrimination thresholds) were significantly correlated with and accounted for up to 13% of the variance in reading related skills. Among children with more than one year of musical training, auditory processing indices were better, yet reading related skills were not correlated with them. A potential interpretation for the reduction in the correlations might be that auditory and reading-related skills improve at different rates as a function of musical training. Conclusions/Significance Participants’ previous musical training, which is typically ignored in studies assessing the relations between auditory and reading related skills, should be considered. Very poor auditory and memory skills are rare among children with even a short period of musical training, suggesting musical training could have an impact on both. The lack of correlation in the musically trained population suggests that a short period of musical training does not enhance reading related skills of individuals with within-normal auditory processing skills. Further studies are required to determine whether the associations between musical training, auditory processing and memory are indeed causal or whether children with poor auditory and memory skills are less likely to study music and if so, why this is the case. PMID:24086654

  13. Photomorphogenic responses to ultraviolet-B light.

    PubMed

    Jenkins, Gareth I

    2017-11-01

    Exposure to ultraviolet B (UV-B) light regulates numerous aspects of plant metabolism, morphology and physiology through the differential expression of hundreds of genes. Photomorphogenic responses to UV-B are mediated by the photoreceptor UV RESISTANCE LOCUS8 (UVR8). Considerable progress has been made in understanding UVR8 action: the structural basis of photoreceptor function, how interaction with CONSTITUTIVELY PHOTOMORPHOGENIC 1 initiates signaling and how REPRESSOR OF UV-B PHOTOMORPHOGENESIS proteins negatively regulate UVR8 action. In addition, recent research shows that UVR8 mediates several responses through interaction with other signaling pathways, in particular auxin signaling. Nevertheless, many aspects of UVR8 action remain poorly understood. Most research to date has been undertaken with Arabidopsis, and it is important to explore the functions and regulation of UVR8 in diverse plant species. Furthermore, it is essential to understand how UVR8, and UV-B signaling in general, regulates processes under natural growth conditions. Ultraviolet B regulates the expression of many genes through UVR8-independent pathways, but the activity and importance of these pathways in plants growing in sunlight are poorly understood. © 2017 John Wiley & Sons Ltd.

  14. Photoperiod cues and patterns of genetic variation limit phenological responses to climate change in warm parts of species’ range: Modeling diameter-growth cessation in coast Douglas-fir

    Treesearch

    Kevin R. Ford; Constance A. Harrington; J. Bradley St. Clair

    2017-01-01

    The phenology of diameter-growth cessation in trees will likely play a key role in mediating species and ecosystem responses to climate change. A common expectation is that warming will delay cessation, but the environmental and genetic influences on this process are poorly understood. We modeled the effects of temperature, photoperiod, and seed-source climate on...

  15. Nitrogen cycling models and their application to forest harvesting

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

    Johnson, D.W.; Dale, V.H.

    1986-01-01

    The characterization of forest nitrogen- (N-) cycling processes by several N-cycling models (FORCYTE, NITCOMP, FORTNITE, and LINKAGES) is briefly reviewed and evaluated against current knowledge of N cycling in forests. Some important processes (e.g., translocation within trees, N dynamics in decaying leaf litter) appear to be well characterized, whereas others (e.g., N mineralization from soil organic matter, N fixation, N dynamics in decaying wood, nitrification, and nitrate leaching) are poorly characterized, primarily because of a lack of knowledge rather than an oversight by model developers. It is remarkable how well the forest models do work in the absence of datamore » on some key processes. For those systems in which the poorly understood processes could cause major changes in N availability or productivity, the accuracy of model predictions should be examined. However, the development of N-cycling models represents a major step beyond the much simpler, classic conceptual models of forest nutrient cycling developed by early investigators. The new generation of computer models will surely improve as research reveals how key nutrient-cycling processes operate.« less

  16. Deconstructing and Reconstructing Cognitive Performance in Sleep Deprivation

    PubMed Central

    Jackson, Melinda L.; Gunzelmann, Glenn; Whitney, Paul; Hinson, John M.; Belenky, Gregory; Rabat, Arnaud; Van Dongen, Hans P. A.

    2012-01-01

    Summary Mitigation of cognitive impairment due to sleep deprivation in operational settings is critical for safety and productivity. Achievements in this area are hampered by limited knowledge about the effects of sleep loss on actual job tasks. Sleep deprivation has different effects on different cognitive performance tasks, but the mechanisms behind this task-specificity are poorly understood. In this context it is important to recognize that cognitive performance is not a unitary process, but involves a number of component processes. There is emerging evidence that these component processes are differentially affected by sleep loss. Experiments have been conducted to decompose sleep-deprived performance into underlying cognitive processes using cognitive-behavioral, neuroimaging and cognitive modeling techniques. Furthermore, computational modeling in cognitive architectures has been employed to simulate sleep-deprived cognitive performance on the basis of the constituent cognitive processes. These efforts are beginning to enable quantitative prediction of the effects of sleep deprivation across different task contexts. This paper reviews a rapidly evolving area of research, and outlines a theoretical framework in which the effects of sleep loss on cognition may be understood from the deficits in the underlying neurobiology to the applied consequences in real-world job tasks. PMID:22884948

  17. Deconstructing and reconstructing cognitive performance in sleep deprivation.

    PubMed

    Jackson, Melinda L; Gunzelmann, Glenn; Whitney, Paul; Hinson, John M; Belenky, Gregory; Rabat, Arnaud; Van Dongen, Hans P A

    2013-06-01

    Mitigation of cognitive impairment due to sleep deprivation in operational settings is critical for safety and productivity. Achievements in this area are hampered by limited knowledge about the effects of sleep loss on actual job tasks. Sleep deprivation has different effects on different cognitive performance tasks, but the mechanisms behind this task-specificity are poorly understood. In this context it is important to recognize that cognitive performance is not a unitary process, but involves a number of component processes. There is emerging evidence that these component processes are differentially affected by sleep loss. Experiments have been conducted to decompose sleep-deprived performance into underlying cognitive processes using cognitive-behavioral, neuroimaging and cognitive modeling techniques. Furthermore, computational modeling in cognitive architectures has been employed to simulate sleep-deprived cognitive performance on the basis of the constituent cognitive processes. These efforts are beginning to enable quantitative prediction of the effects of sleep deprivation across different task contexts. This paper reviews a rapidly evolving area of research, and outlines a theoretical framework in which the effects of sleep loss on cognition may be understood from the deficits in the underlying neurobiology to the applied consequences in real-world job tasks. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. The solar dynamo

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    1994-01-01

    The solar dynamo is the process by which the Sun's magnetic field is generated through the interaction of the field with convection and rotation. In this, it is kin to planetary dynamos and other stellar dynamos. Although the precise mechanism by which the Sun generates its field remains poorly understood in spite of decades of theoretical and observational work, recent advances suggest that solutions to this solar dynamo problem may be forthcoming. The two basic processes involved in dynamo activity are demonstrated and the Sun's activity effects are presented in this document, along with a historical perspective regarding solar dynamos and the efforts to understand and measure them.

  19. Ecology. Three-Gorges Dam--experiment in habitat fragmentation?

    PubMed

    Wu, Jianguo; Huang, Jianhui; Han, Xingguo; Xie, Zongqiang; Gao, Xianming

    2003-05-23

    Habitat fragmentation is the primary cause of the loss of biodiversity and ecosystem services, but its underlying processes and mechanisms remain poorly understood. Studies of islands and insular terrestrial habitats are essential for improving our understanding of habitat fragmentation. We argue that the Three-Gorges Dam, the largest that humans have ever created, presents a unique grand-scale natural experiment that allows ecologists to address a range of critical questions concerning the theory and practice of biodiversity conservation.

  20. Remote Sensing and Geologic Studies of Mare Australe: The North Australe Region

    NASA Technical Reports Server (NTRS)

    Lawrence, S. J.; Stopar, J. D.; Ostrach, L. R.; van der Bogert, C. H.; Hiesinger, H.; Jolliff, B. L.; Giguere, T. A.; Sato, H.; Robinson, M. S.

    2017-01-01

    A key goal of the Lunar Reconnaissance Orbiter (LRO) mission is to investigate volcanic processes at different temporal and physical scales, with one emphasis being the characterization of ancient (meaning, greater than 3.9 Ga) volcanic units. One such ancient volcanic terrain is Mare Australe, a loosely-circular collection of mare basalts centered at approximately 38.9 deg S, 93 deg E (Fig. 1). Mare Australe is a complex, extensive, and poorly understood volcanic region.

  1. Transgenerational effects of insecticides-implications for rapid pest evolution in agroecosystems.

    PubMed

    Brevik, Kristian; Lindström, Leena; McKay, Stephanie D; Chen, Yolanda H

    2018-04-01

    Although pesticides are a major selective force in driving the evolution of insect pests, the evolutionary processes that give rise to insecticide resistance remain poorly understood. Insecticide resistance has been widely observed to increase with frequent and intense insecticide exposure, but can be lost following the relaxation of insecticide use. One possible but rarely explored explanation is that insecticide resistance may be associated with epigenetic modifications, which influence the patterning of gene expression without changing underlying DNA sequence. Epigenetic modifications such as DNA methylation, histone modifications, and small RNAs have been observed to be heritable in arthropods, but their role in the context of rapid evolution of insecticide resistance remain poorly understood. Here, we discuss evidence supporting how: firstly, insecticide-induced effects can be transgenerationally inherited; secondly, epigenetic modifications are heritable; and thirdly, epigenetic modifications are responsive to pesticide and xenobiotic stress. Therefore, pesticides may drive the evolution of resistance via epigenetic processes. Moreover, insect pests primed by pesticides may be more tolerant of other stress, further enhancing their success in adapting to agroecosystems. Resolving the role of epigenetic modifications in the rapid evolution of insect pests has the potential to lead to new approaches for integrated pest management as well as improve our understanding of how anthropogenic stress may drive the evolution of insect pests. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. 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

  3. 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

  4. LAD Prize Talk: Lab Astro and the Origins of the Chemical Elements

    NASA Astrophysics Data System (ADS)

    Lawler, James E.

    2017-06-01

    Only a few of the lightest or primordial nuclei were made just after the Big Bang. Other light nuclei up to the Fe-group are made by fusion in stars. Heavier nuclei are made primarily via r(apid)-process and s(low)-process n(eutron)-capture events. Although the s-process n-capture is fairly well understood, the r-process n-capture events remain poorly understood. The relative role of Core Collapse SNe and n-star mergers will likely be understood in the next few decades. I will discuss recent studies of old Metal-Poor stars that are revealing some new details of nucleosynthesis. This progress is due to the availability of high resolution spectra from large ground based telescopes, access to the UV via HST, and better laboratory data. Our laboratory astrophysics program has focused primarily on the measurement of transition probabilities by combining radiative lifetimes with emission branching fractions. The use of Time Resolved Laser Induced Fluorescence (TRLIF) to measure radiative lifetimes in metallic atoms and ions provides an absolute scale for transition probabilities accurate to a few percent [e.g. 1]. The development and application of TRLIF to neutral and ionized atoms of nearly all elements is due to a simple, versatile, and reliable atom/ion beam source based on a hollow cathode discharge [2, 3]. Fourier transform spectrometers (FTSs) are essential in the measurement of emission branching fractions for atoms and ions with dense spectra such as the rare earths [e.g. 4, 5]. A 3 m focal length echelle spectrometer is important to the measurement of weak branches which might otherwise be obscured by multiplex noise in FTS data [6, 7]. References: [1] E. A. Den Hartog et al., ApJS 194: 35 (2011). [2] D. W. Duquette et al., Phys. Rev. A24, 2847 (1981). [3] S. Salih & J. E. Lawler, Phys. Rev. A29, 3753, (1983). [4] J. W. Brault, J. Opt. Soc. Am. 66, 1081 (1976). [5] J. E. Lawler et al., ApJS 182, 51 (2009). [6] M. P. Wood & J. E. Lawler, Appl. Opt. 51, 8407 (2012). [7] C. Sneden et al., ApJ 817:53 (2016).

  5. Template-Directed Copolymerization, Random Walks along Disordered Tracks, and Fractals

    NASA Astrophysics Data System (ADS)

    Gaspard, Pierre

    2016-12-01

    In biology, template-directed copolymerization is the fundamental mechanism responsible for the synthesis of DNA, RNA, and proteins. More than 50 years have passed since the discovery of DNA structure and its role in coding genetic information. Yet, the kinetics and thermodynamics of information processing in DNA replication, transcription, and translation remain poorly understood. Challenging issues are the facts that DNA or RNA sequences constitute disordered media for the motion of polymerases or ribosomes while errors occur in copying the template. Here, it is shown that these issues can be addressed and sequence heterogeneity effects can be quantitatively understood within a framework revealing universal aspects of information processing at the molecular scale. In steady growth regimes, the local velocities of polymerases or ribosomes along the template are distributed as the continuous or fractal invariant set of a so-called iterated function system, which determines the copying error probabilities. The growth may become sublinear in time with a scaling exponent that can also be deduced from the iterated function system.

  6. Disentangling the Role of Entanglement Density and Molecular Alignment in the Mechanical Response of Glassy Polymers

    NASA Astrophysics Data System (ADS)

    O'Connor, Thomas; Robbins, Mark

    Glassy polymers are a ubiquitous part of modern life, but much about their mechanical properties remains poorly understood. Since chains in glassy states are hindered from exploring their conformational entropy, they can't be understood with common entropic network models. Additionally, glassy states are highly sensitive to material history and nonequilibrium distributions of chain alignment and entanglement can be produced during material processing. Understanding how these far-from equilibrium states impact mechanical properties is analytically challenging but essential to optimizing processing methods. We use molecular dynamics simulations to study the yield and strain hardening of glassy polymers as separate functions of the degree of molecular alignment and inter-chain entanglement. We vary chain alignment and entanglement with three different preparation protocols that mimic common processing conditions in and out of solution. We compare our results to common mechanical models of amorphous polymers and assess their applicability to different experimental processing conditions. This research was performed within the Center for Materials in Extreme Dynamic Environments (CMEDE) under the Hopkins Extreme Materials Institute at Johns Hopkins University. Financial support was provided by Grant W911NF-12-2-0022.

  7. Contextual signals in visual cortex.

    PubMed

    Khan, Adil G; Hofer, Sonja B

    2018-06-05

    Vision is an active process. What we perceive strongly depends on our actions, intentions and expectations. During visual processing, these internal signals therefore need to be integrated with the visual information from the retina. The mechanisms of how this is achieved by the visual system are still poorly understood. Advances in recording and manipulating neuronal activity in specific cell types and axonal projections together with tools for circuit tracing are beginning to shed light on the neuronal circuit mechanisms of how internal, contextual signals shape sensory representations. Here we review recent work, primarily in mice, that has advanced our understanding of these processes, focusing on contextual signals related to locomotion, behavioural relevance and predictions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. The cell biology of polycystic kidney disease

    PubMed Central

    Chapin, Hannah C.

    2010-01-01

    Polycystic kidney disease is a common genetic disorder in which fluid-filled cysts displace normal renal tubules. Here we focus on autosomal dominant polycystic kidney disease, which is attributable to mutations in the PKD1 and PKD2 genes and which is characterized by perturbations of renal epithelial cell growth control, fluid transport, and morphogenesis. The mechanisms that connect the underlying genetic defects to disease pathogenesis are poorly understood, but their exploration is shedding new light on interesting cell biological processes and suggesting novel therapeutic targets. PMID:21079243

  9. Seborrheic Dermatitis

    PubMed Central

    Berk, Thomas; Scheinfeld, Noah

    2010-01-01

    Abstract Seborrheic dermatitis is a common chronic inflammatory skin condition, characterized by scaling and poorly defined erythematous patches. It may be associated with pruritus, and it primarily affects sebum-rich areas, such as the scalp, face, upper chest, and back. Although its pathogenesis is not completely understood, some postulate that the condition results from colonization of the skin of affected individuals with species of the genus Malassezia (formerly, Pityrosporum). A variety of treatment modalities are available, including eradication of the fungus, reducing or treating the inflammatory process, and decreasing sebum production. PMID:20592880

  10. Association of impaired facial affect recognition with basic facial and visual processing deficits in schizophrenia.

    PubMed

    Norton, Daniel; McBain, Ryan; Holt, Daphne J; Ongur, Dost; Chen, Yue

    2009-06-15

    Impaired emotion recognition has been reported in schizophrenia, yet the nature of this impairment is not completely understood. Recognition of facial emotion depends on processing affective and nonaffective facial signals, as well as basic visual attributes. We examined whether and how poor facial emotion recognition in schizophrenia is related to basic visual processing and nonaffective face recognition. Schizophrenia patients (n = 32) and healthy control subjects (n = 29) performed emotion discrimination, identity discrimination, and visual contrast detection tasks, where the emotionality, distinctiveness of identity, or visual contrast was systematically manipulated. Subjects determined which of two presentations in a trial contained the target: the emotional face for emotion discrimination, a specific individual for identity discrimination, and a sinusoidal grating for contrast detection. Patients had significantly higher thresholds (worse performance) than control subjects for discriminating both fearful and happy faces. Furthermore, patients' poor performance in fear discrimination was predicted by performance in visual detection and face identity discrimination. Schizophrenia patients require greater emotional signal strength to discriminate fearful or happy face images from neutral ones. Deficient emotion recognition in schizophrenia does not appear to be determined solely by affective processing but is also linked to the processing of basic visual and facial information.

  11. Linking Family Economic Hardship to Early Childhood Health: An Investigation of Mediating Pathways.

    PubMed

    Hsu, Hui-Chin; Wickrama, Kandauda A S

    2015-12-01

    The underlying mechanisms through which family economic adversity influences child health are less understood. Taking a process-oriented approach, this study examined maternal mental health and investment in children, child health insurance, and child healthcare as mediators linking family economic hardship (FEH) to child health. A structural equation modeling was applied to test the hypothesized mediating model. After adjustment for sociodemographic risk factors, results revealed: (1) a significant direct path linking FEH to poor child health (effect size = .372), and (2) six significant mediating pathways (total effect size = .089). In two mediating pathways, exposures to FEH undermined mothers' mental health: in the first pathway poor maternal mental health led to decreased parental investment, which, in turn, contributed to poor child health, whereas in the second pathway the adverse effect of poor maternal mental health was cascaded through child unmet healthcare need, which resulted in poor child health. One pathway involved child insurance status, where the effect of FEH increased the likelihood to be uninsured, which led to unmet healthcare need, and, in turn, to poor health. Three pathways involved preventive care: in one pathway FEH contributed to poor preventive care, which led to unmet healthcare need and then to poor health; in the other two pathways where poor preventive care respectively gave rise to decreased investment in children or poor maternal mental health, which further contributed to poor child health. Results suggest that the association between FEH and children's health is mediated by multiple pathways.

  12. Patterns and causes of observed piñon pine mortality in the southwestern United States

    USGS Publications Warehouse

    Meddens, Arjan J.H.; Hicke, Jeff H.; Macalady, Alison K.; Buotte, P.C.; Cowles, T.R.; Allen, Craig D.

    2015-01-01

    Recently, widespread piñon pine die-off occurred in the southwestern United States. Here we synthesize observational studies of this event and compare findings to expected relationships with biotic and abiotic factors. Agreement exists on the occurrence of drought, presence of bark beetles and increased mortality of larger trees. However, studies disagree about the influences of stem density, elevation and other factors, perhaps related to study design, location and impact of extreme drought. Detailed information about bark beetles is seldom reported and their role is poorly understood. Our analysis reveals substantial limits to our knowledge regarding the processes that produce mortality patterns across space and time, indicating a poor ability to forecast mortality in response to expected increases in future droughts.

  13. [Communication of scientific fraud].

    PubMed

    Zeitoun, Jean-David; Rouquette, Sébastien

    2012-09-01

    There is for a scientific journal several levels of communication depending of the degree of suspicion or certainty of a case of error or fraud. The task is increasingly difficult for journal editors as disclosed cases of fraud are more common and scientific communication on this topic is growing. Biomedical fraud is fairly little reported by the mainstream press and causes of this low interest are not currently well understood. The difficulty of processing this type of news for journalists appears to be one possible reason. The potentially numerous and significant consequences of fraud on health professionals are poorly documented. Though it is likely to cause a feeling of distrust and create controversy, the impact of fraud on the general public is poorly studied and appears multifactorial. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  14. Modelling fungal growth in heterogeneous soil: analyses of the effect of soil physical structure on fungal community dynamics

    NASA Astrophysics Data System (ADS)

    Falconer, R.; Radoslow, P.; Grinev, D.; Otten, W.

    2009-04-01

    Fungi play a pivital role in soil ecosystems contributing to plant productivity. The underlying soil physical and biological processes responsible for community dynamics are interrelated and, at present, poorly understood. If these complex processes can be understood then this knowledge can be managed with an aim to providing more sustainable agriculture. Our understanding of microbial dynamics in soil has long been hampered by a lack of a theoretical framework and difficulties in observation and quantification. We will demonstrate how the spatial and temporal dynamics of fungi in soil can be understood by linking mathematical modelling with novel techniques that visualise the complex structure of the soil. The combination of these techniques and mathematical models opens up new possibilities to understand how the physical structure of soil affects fungal colony dynamics and also how fungal dynamics affect soil structure. We will quantify, using X ray tomography, soil structure for a range of artificially prepared microcosms. We characterise the soil structures using soil metrics such as porosity, fractal dimension, and the connectivity of the pore volume. Furthermore we will use the individual based fungal colony growth model of Falconer et al. 2005, which is based on the physiological processes of fungi, to assess the effect of soil structure on microbial dynamics by qualifying biomass abundances and distributions. We demonstrate how soil structure can critically affect fungal species interactions with consequences for biological control and fungal biodiversity.

  15. Single-Dose Testosterone Administration Impairs Cognitive Reflection in Men.

    PubMed

    Nave, Gideon; Nadler, Amos; Zava, David; Camerer, Colin

    2017-10-01

    In nonhumans, the sex steroid testosterone regulates reproductive behaviors such as fighting between males and mating. In humans, correlational studies have linked testosterone with aggression and disorders associated with poor impulse control, but the neuropsychological processes at work are poorly understood. Building on a dual-process framework, we propose a mechanism underlying testosterone's behavioral effects in humans: reduction in cognitive reflection. In the largest study of behavioral effects of testosterone administration to date, 243 men received either testosterone or placebo and took the Cognitive Reflection Test (CRT), which estimates the capacity to override incorrect intuitive judgments with deliberate correct responses. Testosterone administration reduced CRT scores. The effect remained after we controlled for age, mood, math skills, whether participants believed they had received the placebo or testosterone, and the effects of 14 additional hormones, and it held for each of the CRT questions in isolation. Our findings suggest a mechanism underlying testosterone's diverse effects on humans' judgments and decision making and provide novel, clear, and testable predictions.

  16. Wound repair and regeneration: mechanisms, signaling, and translation.

    PubMed

    Eming, Sabine A; Martin, Paul; Tomic-Canic, Marjana

    2014-12-03

    The cellular and molecular mechanisms underpinning tissue repair and its failure to heal are still poorly understood, and current therapies are limited. Poor wound healing after trauma, surgery, acute illness, or chronic disease conditions affects millions of people worldwide each year and is the consequence of poorly regulated elements of the healthy tissue repair response, including inflammation, angiogenesis, matrix deposition, and cell recruitment. Failure of one or several of these cellular processes is generally linked to an underlying clinical condition, such as vascular disease, diabetes, or aging, which are all frequently associated with healing pathologies. The search for clinical strategies that might improve the body's natural repair mechanisms will need to be based on a thorough understanding of the basic biology of repair and regeneration. In this review, we highlight emerging concepts in tissue regeneration and repair, and provide some perspectives on how to translate current knowledge into viable clinical approaches for treating patients with wound-healing pathologies. Copyright © 2014, American Association for the Advancement of Science.

  17. Wound repair and regeneration: Mechanisms, signaling, and translation

    PubMed Central

    Eming, Sabine A.; Martin, Paul; Tomic-Canic, Marjana

    2015-01-01

    The cellular and molecular mechanisms underpinning tissue repair and its failure to heal are still poorly understood, and current therapies are limited. Poor wound healing after trauma, surgery, acute illness, or chronic disease conditions affects millions of people worldwide each year and is the consequence of poorly regulated elements of the healthy tissue repair response, including inflammation, angiogenesis, matrix deposition, and cell recruitment. Failure of one or several of these cellular processes is generally linked to an underlying clinical condition, such as vascular disease, diabetes, or aging, which are all frequently associated with healing pathologies. The search for clinical strategies that might improve the body’s natural repair mechanisms will need to be based on a thorough understanding of the basic biology of repair and regeneration. In this review, we highlight emerging concepts in tissue regeneration and repair, and provide some perspectives on how to translate current knowledge into viable clinical approaches for treating patients with wound-healing pathologies. PMID:25473038

  18. Interoception, contemplative practice, and health

    PubMed Central

    Farb, Norman; Daubenmier, Jennifer; Price, Cynthia J.; Gard, Tim; Kerr, Catherine; Dunn, Barnaby D.; Klein, Anne Carolyn; Paulus, Martin P.; Mehling, Wolf E.

    2015-01-01

    Interoception can be broadly defined as the sense of signals originating within the body. As such, interoception is critical for our sense of embodiment, motivation, and well-being. And yet, despite its importance, interoception remains poorly understood within modern science. This paper reviews interdisciplinary perspectives on interoception, with the goal of presenting a unified perspective from diverse fields such as neuroscience, clinical practice, and contemplative studies. It is hoped that this integrative effort will advance our understanding of how interoception determines well-being, and identify the central challenges to such understanding. To this end, we introduce an expanded taxonomy of interoceptive processes, arguing that many of these processes can be understood through an emerging predictive coding model for mind–body integration. The model, which describes the tension between expected and felt body sensation, parallels contemplative theories, and implicates interoception in a variety of affective and psychosomatic disorders. We conclude that maladaptive construal of bodily sensations may lie at the heart of many contemporary maladies, and that contemplative practices may attenuate these interpretative biases, restoring a person’s sense of presence and agency in the world. PMID:26106345

  19. Electronic and Chemical Properties of a Surface-Terminated Screw Dislocation in MgO

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

    Mckenna, Keith P.

    2013-12-18

    Dislocations represent an important and ubiquitous class of topological defect found at the surfaces of metal oxide materials. They are thought to influence processes as diverse as crystal growth, corrosion, charge trapping, luminescence, molecular adsorption and catalytic activity, however, their electronic and chemical properties remain poorly understood. Here, through a detailed first principles investigation into the properties of a surface terminated screw dislocation in MgO we provide atomistic insight into these issues. We show that surface dislocations can exhibit intriguing electron trapping properties which are important for understanding the chemical and electronic characteristics of oxide surfaces. The results presented inmore » this article taken together with recent experimental reports show that surface dislocations can be equally as important as more commonly considered surface defects, such as steps, kinks and vacanies, but are now just beginning to be understood.« less

  20. Electronic and Chemical Properties of a Surface-Terminated Screw Dislocation in MgO

    PubMed Central

    2013-01-01

    Dislocations represent an important and ubiquitous class of topological defect found at the surfaces of metal oxide materials. They are thought to influence processes as diverse as crystal growth, corrosion, charge trapping, luminescence, molecular adsorption, and catalytic activity; however, their electronic and chemical properties remain poorly understood. Here, through a detailed first-principles investigation into the properties of a surface-terminated screw dislocation in MgO we provide atomistic insight into these issues. We show that surface dislocations can exhibit intriguing electron trapping properties which are important for understanding the chemical and electronic characteristics of oxide surfaces. The results presented in this article taken together with recent experimental reports show that surface dislocations can be equally as important as more commonly considered surface defects, such as steps, kinks, and vacancies, but are now just beginning to be understood. PMID:24279391

  1. 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…

  2. Mechanics and morphogenesis of fission yeast cells.

    PubMed

    Davì, Valeria; Minc, Nicolas

    2015-12-01

    The integration of biochemical and biomechanical elements is at the heart of morphogenesis. While animal cells are relatively soft objects which shape and mechanics is mostly regulated by cytoskeletal networks, walled cells including those of plants, fungi and bacteria are encased in a rigid cell wall which resist high internal turgor pressure. How these particular mechanical properties may influence basic cellular processes, such as growth, shape and division remains poorly understood. Recent work using the model fungal cell fission yeast, Schizosaccharomyces pombe, highlights important contribution of cell mechanics to various morphogenesis processes. We envision this genetically tractable system to serve as a novel standard for the mechanobiology of walled cell. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Retail Buildings: Assessing and Reducing Plug and Process Loads in Retail Buildings (Fact Sheet)

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

    Not Available

    2013-04-01

    Plug and process loads (PPLs) in commercial buildings account for almost 5% of U.S. primary energy consumption. Minimizing these loads is a primary challenge in the design and operation of an energy-efficient building. PPLs are not related to general lighting, heating, ventilation, cooling, and water heating, and typically do not provide comfort to the occupants. They use an increasingly large fraction of the building energy use pie because the number and variety of electrical devices have increased along with building system efficiency. Reducing PPLs is difficult because energy efficiency opportunities and the equipment needed to address PPL energy use inmore » retail spaces are poorly understood.« less

  4. Electrocortical measures of information processing biases in social anxiety disorder: A review.

    PubMed

    Harrewijn, Anita; Schmidt, Louis A; Westenberg, P Michiel; Tang, Alva; van der Molen, Melle J W

    2017-10-01

    Social anxiety disorder (SAD) is characterized by information processing biases, however, their underlying neural mechanisms remain poorly understood. The goal of this review was to give a comprehensive overview of the most frequently studied EEG spectral and event-related potential (ERP) measures in social anxiety during rest, anticipation, stimulus processing, and recovery. A Web of Science search yielded 35 studies reporting on electrocortical measures in individuals with social anxiety or related constructs. Social anxiety was related to increased delta-beta cross-frequency correlation during anticipation and recovery, and information processing biases during early processing of faces (P1) and errors (error-related negativity). These electrocortical measures are discussed in relation to the persistent cycle of information processing biases maintaining SAD. Future research should further investigate the mechanisms of this persistent cycle and study the utility of electrocortical measures in early detection, prevention, treatment and endophenotype research. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. 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

  6. Star Formation Quenching, How Fast And How Frequently? Inside-Out Or Not?

    NASA Astrophysics Data System (ADS)

    Lian, Jianhui; Yan, Renbin; Blanton, Michael; Zhang, Kai; Kong, Xu

    2017-06-01

    Star formation quenching is a critical process that drive galaxies evolving from blue star-forming to red passive stage. This rapid quenching process is necessary in galaxy evolution models to explain the galaxy distribution in NUV-optical colour-colour diagrams1,2 and the buildup of red-sequence from z = 1 to z = 03,4,5. Yet, the mechanism of this quenching process is not fully understood and is of hot debate. Many candidate scenarios, such as strangulation due to shock heating in massive halos, AGN feedback or gas stripping due to environmental effect, have been proposed. To differentiate these scenarios, more constraints on the quenching process and thus the potential physical mechanism are badly needed. The first result we show in this poster is the properties of quenching process we obtained from the galaxy distribution in NUV-optical colour-colour diagrams. Aside from the unclear integrated star formation history (SFH) of galaxies, how the SFH of galaxies varies internally is still poorly understood. One direct probe of the internal variation of SFH is the spatial distribution of colours, i.e. the colour gradient. In the second part of the results of this poster, we explicitly illustrate the definition of 'inside-out growth' and 'inside-out quenching' scenarios and utilize the galaxy distribution in the u-I colour gradients to see which one is more observationally favoured.

  7. Lexical Processing in School-Age Children with Autism Spectrum Disorder and Children with Specific Language Impairment: The Role of Semantics.

    PubMed

    Haebig, Eileen; Kaushanskaya, Margarita; Ellis Weismer, Susan

    2015-12-01

    Children with autism spectrum disorder (ASD) and specific language impairment (SLI) often have immature lexical-semantic knowledge; however, the organization of lexical-semantic knowledge is poorly understood. This study examined lexical processing in school-age children with ASD, SLI, and typical development, who were matched on receptive vocabulary. Children completed a lexical decision task, involving words with high and low semantic network sizes and nonwords. Children also completed nonverbal updating and shifting tasks. Children responded more accurately to words from high than from low semantic networks; however, follow-up analyses identified weaker semantic network effects in the SLI group. Additionally, updating and shifting abilities predicted lexical processing, demonstrating similarity in the mechanisms which underlie semantic processing in children with ASD, SLI, and typical development.

  8. Lexical Processing in School-Age Children with Autism Spectrum Disorder and Children with Specific Language Impairment: The Role of Semantics

    PubMed Central

    Haebig, Eileen; Kaushanskaya, Margarita; Weismer, Susan Ellis

    2016-01-01

    Children with autism spectrum disorder (ASD) and specific language impairment (SLI) often have immature lexical-semantic knowledge; however, the organization of lexical-semantic knowledge is poorly understood. This study examined lexical processing in school-age children with ASD, SLI, and typical development, who were matched on receptive vocabulary. Children completed a lexical decision task, involving words with high and low semantic network sizes and nonwords. Children also completed nonverbal updating and shifting tasks. Children responded more accurately to words from high than from low semantic networks; however, follow-up analyses identified weaker semantic network effects in the SLI group. Additionally, updating and shifting abilities predicted lexical processing, demonstrating similarity in the mechanisms which underlie semantic processing in children with ASD, SLI, and typical development. PMID:26210517

  9. Light Signaling in Bud Outgrowth and Branching in Plants

    PubMed Central

    Leduc, Nathalie; Roman, Hanaé; Barbier, François; Péron, Thomas; Huché-Thélier, Lydie; Lothier, Jérémy; Demotes-Mainard, Sabine; Sakr, Soulaiman

    2014-01-01

    Branching determines the final shape of plants, which influences adaptation, survival and the visual quality of many species. It is an intricate process that includes bud outgrowth and shoot extension, and these in turn respond to environmental cues and light conditions. Light is a powerful environmental factor that impacts multiple processes throughout plant life. The molecular basis of the perception and transduction of the light signal within buds is poorly understood and undoubtedly requires to be further unravelled. This review is based on current knowledge on bud outgrowth-related mechanisms and light-mediated regulation of many physiological processes. It provides an extensive, though not exhaustive, overview of the findings related to this field. In parallel, it points to issues to be addressed in the near future. PMID:27135502

  10. Jupiter radio bursts and particle acceleration

    NASA Technical Reports Server (NTRS)

    Desch, Michael D.

    1994-01-01

    Particle acceleration processes are important in understanding many of the Jovian radio and plasma wave emissions. However, except for the high-energy electrons that generate synchrotron emission following inward diffusion from the outer magnetosphere, acceleration processes in Jupiter's magnetosphere and between Jupiter and Io are poorly understood. We discuss very recent observations from the Ulysses spacecraft of two new Jovian radio and plamas wave emissions in which particle acceleration processes are important and have been addressed directly by complementary investigations. First, radio bursts known as quasi-periodic bursts have been observed in close association with a population of highly energetic electrons. Second, a population of much lower energy (keV range) electrons on auroral field lines can be shown to be responsible for the first observation of a Jovian plasma wave emission known as auroral hiss.

  11. 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

  12. Supporting Pakistani and Chinese families with young children: perspectives of mothers and health visitors.

    PubMed

    Hogg, R; de Kok, B; Netto, G; Hanley, J; Haycock-Stuart, E

    2015-05-01

    In the UK, public health nurses (health visitors) provide support and advice to families with young children, including those from minority ethnic communities. While the need for cultural sensitivity is being increasingly recognized, the factors which contribute to this sensitivity are poorly understood. The Pakistani and Chinese communities constitute the two largest minority ethnic groups in Scotland. This study explored Pakistani and Chinese women's experience of motherhood and of the health visiting service and public health nurses' experiences of working with Chinese and Pakistani mothers. Semi-structured individual interviews were carried out with 16 Pakistani and 15 Chinese mothers. Eight health visitors took part in two focus groups. The study was undertaken in an urban area of Scotland. Data were analysed thematically. Chinese and Pakistani mothers negotiate complex processes in order to ensure that their children maintain their own ethnic identity while fitting in with their peers in their adopted country. Health visitors were seen as supportive, although sometimes advice and information given was culturally inappropriate, and their role was often poorly understood. Health visitors were anxious to be sensitive to families' religious and cultural beliefs. Cultural sensitivity is an important factor in providing appropriate advice and help to Pakistani and Chinese families, and involves health visitors in considering views and practices on parenting which may differ across cultures, including their own. Family characteristics need to be understood on an individual basis, rather than making assumptions about clients' cultural norms and lifestyles. This is best achieved by exploring with mothers if they understand the advice and information they are being offered and also if it is appropriate to their cultural and religious beliefs. © 2014 John Wiley & Sons Ltd.

  13. Early childhood growth failure and the developmental origins of adult disease: Do enteric infections and malnutrition increase risk for the metabolic syndrome?

    PubMed Central

    DeBoer, Mark D.; Lima, Aldo A. M.; Oría, Reinaldo B.; Scharf, Rebecca J.; Moore, Sean R.; Luna, Max A.; Guerrant, Richard L.

    2012-01-01

    Hypotheses regarding the developmental origins of health and disease postulate that developing fetuses–and potentially young children—undergo adaptive epigenetic changes with longstanding effects on metabolism and other processes. Ongoing research explores whether these adaptations occur during early life following malnutrition. In the developing world there remains a high degree of nutritional stunting—linear growth failure due to inadequate calories that may be exacerbated by inflammation from ongoing infections. In areas with poor sanitation children experience vicious cycles of enteric infections and malnutrition, resulting in poor nutrient absorption from intestinal mucosa changes now termed “environmental enteropathy.” Emerging evidence links early childhood diarrhea and/or growth failure with increased CVD risk factors in later life, including dyslipidemia, hypertension and glucose intolerance. The mechanisms for these associations remain poorly understood and may relate to epigenetic responses to poor nutrition, increased inflammation or both. Given increases in CVD in developing areas of the world, associations between childhood malnutrition, early life infections and increased CVD risk factors underscore further reasons to improve nutrition and infection-related outcomes for young children worldwide. PMID:23110643

  14. The impact of threat of shock on the framing effect and temporal discounting: executive functions unperturbed by acute stress?

    PubMed

    Robinson, Oliver J; Bond, Rebecca L; Roiser, Jonathan P

    2015-01-01

    Anxiety and stress-related disorders constitute a large global health burden, but are still poorly understood. Prior work has demonstrated clear impacts of stress upon basic cognitive function: biasing attention toward unexpected and potentially threatening information and instantiating a negative affective bias. However, the impact that these changes have on higher-order, executive, decision-making processes is unclear. In this study, we examined the impact of a translational within-subjects stress induction (threat of unpredictable shock) on two well-established executive decision-making biases: the framing effect (N = 83), and temporal discounting (N = 36). In both studies, we demonstrate (a) clear subjective effects of stress, and (b) clear executive decision-making biases but (c) no impact of stress on these decision-making biases. Indeed, Bayes factor analyses confirmed substantial preference for decision-making models that did not include stress. We posit that while stress may induce subjective mood change and alter low-level perceptual and action processes (Robinson et al., 2013c), some higher-level executive processes remain unperturbed by these impacts. As such, although stress can induce a transient affective biases and altered mood, these need not result in poor financial decision-making.

  15. The scientific challenges to forecasting and nowcasting the magnetospheric response to space weather (Invited)

    NASA Astrophysics Data System (ADS)

    Hesse, M.; Kuznetsova, M. M.; Birn, J.; Pulkkinen, A. A.

    2013-12-01

    Space weather is different from terrestrial weather in an essential way. Terrestrial weather has benefitted from a long history of research, which has led to a deep and detailed level of understanding. In comparison, space weather is scientifically in its infancy. Many key processes in the causal chains from processes on the Sun to space weather effects in various locations in the heliosphere remain either poorly understood or not understood at all. Space weather is therefore, and will remain in the foreseeable future, primarily a research field. Extensive further research efforts are needed before we can reasonably expect the precision and fidelity of weather forecasts. For space weather within the Earth's magnetosphere, the coupling between solar wind and magnetosphere is of crucial importance. While past research has provided answers, often on qualitative levels, to some of the most fundamental questions, answers to some of the latter and the ability to predict quantitatively remain elusive. This presentation will provide an overview of pertinent aspects of solar wind-magnetospheric coupling, its importance for space weather near the Earth, and it will analyze the state of our ability to describe and predict its efficiency. It will conclude with a discussion of research activities, which are aimed at improving our ability to quantitatively forecast coupling processes.

  16. An aegialodontid upper molar and the evolution of mammal dentition.

    PubMed

    Lopatin, Alexey V; Averianov, Alexander O

    2006-08-25

    The most obvious key synapomorphy of the therian mammals is the tribosphenic pattern of their molars. Tribosphenic teeth are capable of both shearing and grinding, which substantially increase effectiveness of food processing and, in turn, permit evolution of a wide range of dietary specializations. Functional tribospheny developed repeatedly during mammalian evolution but was successful only in the Boreosphenida. The earliest stage in the development of boreosphenidan tribospheny has remained poorly understood, being documented only by lower molars of aegialodontids. Here, we report a known upper molar of an aegialodontid mammal, Kielantherium, from the Early Cretaceous of Mongolia.

  17. Mechanisms of, and Adjuvants for, Bone Pain.

    PubMed

    Figura, Nicholas; Smith, Joshua; Yu, Hsiang-Hsuan Michael

    2018-06-01

    Metastatic bone pain is a complex, poorly understood process. Understanding the unique mechanisms causing cancer-induced bone pain may lead to potential therapeutic targets. This article discusses the effects of osteoclast overstimulation within the tumor microenvironment; the role of inflammatory factors at the tumor-nociceptor interface; the development of structural instability, causing mechanical nerve damage; and, ultimately, the neuroplastic changes in the setting of sustained pain. Several adjuvant therapies are available to attenuate metastatic bone pain. This article discusses the role of pharmacologic therapies, surgery, kyphoplasty, vertebroplasty, and radiofrequency ablation. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Characterization of human cervical remodeling throughout pregnancy using in vivo Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    O'Brien, Christine M.; Vargis, Elizabeth; Slaughter, Chris; Rudin, Amy P.; Herington, Jennifer L.; Bennett, Kelly A.; Reese, Jeff; Mahadevan-Jansen, Anita

    2015-02-01

    Globally, fifteen million babies are born preterm each year, affecting 1 in 8 pregnancies in the US alone. Cervical remodeling includes a biochemical cascade of changes that ultimately result in the thinning and dilation of the cervix for passage of a fetus. This process is poorly understood and is the focus of this study. Our group is utilizing Raman spectroscopy to evaluate biochemical changes occurring in the human cervix throughout pregnancy. This technique has high molecular specificity and can be performed in vivo, with the potential to unveil new molecular dynamics essential for cervical remodeling.

  19. Paradigm shift in plant growth control.

    PubMed

    Körner, Christian

    2015-06-01

    For plants to grow they need resources and appropriate conditions that these resources are converted into biomass. While acknowledging the importance of co-drivers, the classical view is still that carbon, that is, photosynthetic CO2 uptake, ranks above any other drivers of plant growth. Hence, theory and modelling of growth traditionally is carbon centric. Here, I suggest that this view is not reflecting reality, but emerged from the availability of methods and process understanding at leaf level. In most cases, poorly understood processes of tissue formation and cell growth are governing carbon demand, and thus, CO2 uptake. Carbon can only be converted into biomass to the extent chemical elements other than carbon, temperature or cell turgor permit. Copyright © 2015. Published by Elsevier Ltd.

  20. Impact of Platelet-Rich Plasma on Viability and Proliferation in Wound Healing Processes after External Radiation

    PubMed Central

    Reinders, Yvonne; Felthaus, Oliver; Brockhoff, Gero; Pohl, Fabian; Prantl, Lukas; Haubner, Frank

    2017-01-01

    Platelet-rich plasma is a current subject of studies on chronic wound healing therapy due to possible pro-angiogenic effects. Microvascular compromise represents the major component in radiogenic wound healing complications. The effects of platelet-rich plasma on irradiated cells of the cutaneous wound healing process are poorly understood so far. In this study, the interaction of endothelial cells and adipose-derived stem cells in conjunction with treatment with platelet-rich plasma is investigated in the context of radiation effects. Therefore, the expression of surface-marker CD90 and CD31 was determined. Moreover, cell proliferation and viability after external radiation was analyzed with and without treatment by platelet-rich plasma. PMID:28829358

  1. It's fun to transcribe with Fun30: A model for nucleosome dynamics during RNA polymerase II-mediated elongation.

    PubMed

    Lee, Junwoo; Choi, Eun Shik; Lee, Daeyoup

    2018-01-01

    The ability of elongating RNA polymerase II (RNAPII) to regulate the nucleosome barrier is poorly understood because we do not know enough about the involved factors and we lack a conceptual framework to model this process. Our group recently identified the conserved Fun30/SMARCAD1 family chromatin-remodeling factor, Fun30 Fft3 , as being critical for relieving the nucleosome barrier during RNAPII-mediated elongation, and proposed a model illustrating how Fun30 Fft3 may contribute to nucleosome disassembly during RNAPII-mediated elongation. Here, we present a model that describes nucleosome dynamics during RNAPII-mediated elongation in mathematical terms and addresses the involvement of Fun30 Fft3 in this process.

  2. 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...

  3. 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…

  4. 'Why didn't you write a not-for-cardiopulmonary resuscitation order?' Unexpected death or failure of process?

    PubMed

    Levinson, Michele; Mills, Amber; Barrett, Jonathan; Sritharan, Gaya; Gellie, Anthea

    2018-02-01

    Objective The aim of the present study was to understand the reasons for the delivery of non-beneficial cardiopulmonary resuscitation (CPR) attempts in a tertiary private hospital over 12 months. We determined doctors' expectations of survival after CPR for their patient, whether they had considered a not-for-resuscitation (NFR) order and the barriers to completion of NFR orders. Methods Anonymous questionnaires were sent to the doctors primarily responsible for a given patient's care in the hospital within 2 weeks of the unsuccessful CPR attempt. The data were analysed quantitatively where appropriate and qualitatively for themes for open-text responses Results Most doctors surveyed in the present study understood the poor outcome after CPR in the older person. Most doctors had an expectation that their own patient had a poor prognosis and a poor likely predicted outcome after CPR. This implied that the patient's death was neither unexpected nor likely to be reversible. Some doctors considered NFR orders, but multiple barriers to completion were cited, including the family's wishes, being time poor and diffusion or deferral of responsibility. Conclusions It is likely that futile CPR is provided contrary to policy and legal documents relating to end-of-life care, with the potential for harms relating to both patient and family, and members of resuscitation teams. The failure appears to relate to process rather than recognition of poor patient outcome. What is known about the topic? Mandatory CPR has been established in Australian hospitals on the premise that it will save lives. The outcome from in-hospital cardiac arrest has not improved despite significant training and resources. The outcome for those acutely hospitalised patients aged over 80 years has been repeatedly demonstrated to be poor with significant morbidity in the survivors. There is emerging literature on the extent of the delivery of non-beneficial treatments at the end of life, including futile CPR, the recognition of harms incurred by patients, families and members of the resuscitation teams and on the opportunity cost of the inappropriate use of resources. What does this paper add? This is the first study, to our knowledge, that has demonstrated that doctors understood the outcomes for CPR, particularly in those aged 80 years and older, and that failure to recognise poor outcome and prognosis in their own patients is not a barrier to writing NFR orders. What are the implications for practitioners? Recognition of the poor outcomes from CPR for the elderly patient for whom the doctor has a duty of care should result in a discussion with the patients, allowing an exploration of values and expectations of treatment. This would promote shared decision making, which includes the use of CPR. Facilitation of these discussions should be the focus of health service review.

  5. Origin of Shear Stability and Compressive Ductility Enhancement of Metallic Glasses by Metal Coating

    PubMed Central

    Sun, B. A.; Chen, S. H.; Lu, Y. M.; Zhu, Z. G.; Zhao, Y. L.; Yang, Y.; Chan, K. C.; Liu, C. T.

    2016-01-01

    Metallic glasses (MGs) are notorious for the poor macroscopic ductility and to overcome the weakness various intrinsic and extrinsic strategies have been proposed in past decades. Among them, the metal coating is regarded as a flexible and facile approach, yet the physical origin is poorly understood due to the complex nature of shear banding process. Here, we studied the origin of ductile enhancement in the Cu-coating both experimentally and theoretically. By examining serrated shear events and their stability of MGs, we revealed that the thin coating layer plays a key role in stopping the final catastrophic failure of MGs by slowing down shear band dynamics and thus retarding its attainment to a critical instable state. The mechanical analysis on interplay between the coating layer and shear banding process showed the enhanced shear stability mainly comes from the lateral tension of coating layer induced by the surface shear step and the bonding between the coating layer and MGs rather than the layer thickness is found to play a key role in contributing to the shear stability. PMID:27271435

  6. Care erosion in hospitals: Problems in reflective nursing practice and the role of cognitive dissonance.

    PubMed

    de Vries, Jan; Timmins, Fiona

    2016-03-01

    Care erosion - gradual decline in care level - is an important problem in health care today. Unfortunately, the mechanism whereby it occurs is complex and poorly understood. This paper seeks to address this by emphasising problems in reflective nursing practice. Critical reflection on quality of care which should drive good care instead spawns justifications, denial, and trivialisation of deficient care. This perpetuates increasingly poor care levels. We argue that cognitive dissonance theory provides a highly effective understanding of this process and suggest for this approach to be incorporated in all efforts to address care erosion. The paper includes a detailed discussion of examples and implications for practice, in particular the need to restore critical reflection in nursing, the importance of embracing strong values and standards, and the need for increased awareness of signs of care erosion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. The intact Kunitz domain protects the amyloid precursor protein from being processed by matriptase-2.

    PubMed

    Beckmann, Anna-Madeleine; Glebov, Konstantin; Walter, Jochen; Merkel, Olaf; Mangold, Martin; Schmidt, Frederike; Becker-Pauly, Christoph; Gütschow, Michael; Stirnberg, Marit

    2016-08-01

    Proteolytic processing of the amyloid precursor protein (APP) leads to amyloid-β (Aβ) peptides. So far, the mechanism of APP processing is insufficiently characterized at the molecular level. Whereas the knowledge of Aβ generation by several proteases has been expanded, the contribution of the Kunitz-type protease inhibitor domain (KPI) present in two major APP isoforms to the complex proteolytic processing of APP is poorly understood. In this study, we have identified KPI-containing APP as a very potent, slow-binding inhibitor for the membrane-bound proteolytic regulator of iron homeostasis matriptase-2 by forming stable complexes with its target protease in HEK cells. Inhibition and complex formation depend on the intact KPI domain. By inhibiting matriptase-2, KPI-containing APP is protected from matriptase-2-mediated proteolysis within the Aβ region, thus preventing the generation of N-terminally truncated Aβ.

  8. Characterizing Chain Processes in Visible Light Photoredox Catalysis

    PubMed Central

    Cismesia, Megan A.

    2015-01-01

    The recognition that Ru(bpy)32+ andsimilar visible light absorbing transition metal complexes can be photocatalysts for a variety of synthetically useful organic reactions has resulted in a recent resurgence of interest in photoredox catalysis. However, many of the critical mechanistic aspects of this class of reactions remain poorly understood. In particular, the degree to which visible light photoredox reactions involve radical chain processes has been a point of some disagreement that has not been subjected to systematic analysis. We have now performed quantum yield measurements to demonstrate that threerepresentative, mechanistically distinct photoredox processes involve product-forming chain reactions. Moreover, we show that the combination of quantum yield and luminescence quenching experiments provides a rapid method to estimate the length of these chains. Together, these measurements constitute a robust, operationally facile strategy for characterizing chain processes in a wide range of visible light photoredox reactions. PMID:26668708

  9. Cognitive-Processing Bias in Chinese Student Teachers with Strong and Weak Professional Identity.

    PubMed

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

    2017-01-01

    Professional identity plays an important role in career development. Although many studies have examined professional identity, differences in cognitive-processing biases between Chinese student teachers with strong and weak professional identity are poorly understood. The current study adopted Tversky's social-cognitive experimental paradigm to explore cognitive-processing biases in Chinese student teachers with strong and weak professional identity. Experiment 1 showed that participants with strong professional identity exhibited stronger positive-coding bias toward positive profession-related life events, relative to that observed in those with weak professional identity. Experiment 2 showed that participants with strong professional identity exhibited greater recognition bias for previously read items, relative to that observed in those with weak professional identity. Overall, the results suggested that participants with strong professional identity exhibited greater positive cognitive-processing bias relative to that observed in those with weak professional identity.

  10. Cognitive-Processing Bias in Chinese Student Teachers with Strong and Weak Professional Identity

    PubMed Central

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

    2017-01-01

    Professional identity plays an important role in career development. Although many studies have examined professional identity, differences in cognitive-processing biases between Chinese student teachers with strong and weak professional identity are poorly understood. The current study adopted Tversky’s social-cognitive experimental paradigm to explore cognitive-processing biases in Chinese student teachers with strong and weak professional identity. Experiment 1 showed that participants with strong professional identity exhibited stronger positive-coding bias toward positive profession-related life events, relative to that observed in those with weak professional identity. Experiment 2 showed that participants with strong professional identity exhibited greater recognition bias for previously read items, relative to that observed in those with weak professional identity. Overall, the results suggested that participants with strong professional identity exhibited greater positive cognitive-processing bias relative to that observed in those with weak professional identity. PMID:28555123

  11. Sensitivity, child regulatory processes, and naturally occurring declines in antisocial behavior across childhood.

    PubMed

    Buck, Katharine Ann

    2014-12-01

    Despite considerable research on why antisocial behavior develops and interventions that reduce it, aspects of everyday family processes that may promote naturally occurring declines in antisocial behavior or that may result from such declines in most children without intervention are poorly understood. The current study explored family processes that may enable children to replace antisocial tendencies and the effects that declines in antisocial behavior may have on parenting and child regulatory processes. Longitudinal data from 1,022 children (54 months-6th grade) from the NICHD Study of Early Child Care and Youth Development were examined. Findings demonstrated that naturally occurring declines in antisocial behavior both predicted and were predicted by maternal sensitivity, emotion regulation, and social skills. These declines predicted but were not predicted by declines in hostile attributions. The data revealed multiple indirect paths, which highlight the complex nature of these variables across development.

  12. Region effects influence local tree species diversity.

    PubMed

    Ricklefs, Robert E; He, Fangliang

    2016-01-19

    Global patterns of biodiversity reflect both regional and local processes, but the relative importance of local ecological limits to species coexistence, as influenced by the physical environment, in contrast to regional processes including species production, dispersal, and extinction, is poorly understood. Failure to distinguish regional influences from local effects has been due, in part, to sampling limitations at small scales, environmental heterogeneity within local or regional samples, and incomplete geographic sampling of species. Here, we use a global dataset comprising 47 forest plots to demonstrate significant region effects on diversity, beyond the influence of local climate, which together explain more than 92% of the global variation in local forest tree species richness. Significant region effects imply that large-scale processes shaping the regional diversity of forest trees exert influence down to the local scale, where they interact with local processes to determine the number of coexisting species.

  13. 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

  14. The Role of Microbial Iron Reduction in the Formation of Proterozoic Molar Tooth Structures

    NASA Astrophysics Data System (ADS)

    Hodgskiss, M. S. W.; Kunzmann, M.; Halverson, G. P.; Poirier, A.

    2016-12-01

    Molar tooth structures are poorly understood early diagenetic, microspar-filled voids in clay-rich carbonate sediments. They are a common structure in sedimentary successions dating from 2600-720 Ma, but do not occur in rocks older or younger. Despite being volumetrically significant in carbonate rocks of this age, their formation and disappearance are poorly understood. Here, we present iron isotope data, supported by carbon and oxygen isotopes, major and minor element concentrations, and total organic carbon and pyrite contents for samples from ten regions spanning 1870-635 Ma. The iron isotopic composition of molar tooth structures is almost always lighter (modal depletion of 2‰) than the carbonate or siliciclastic components in the host sediment, whereas carbon isotopes are indistinguishable. We interpret the isotopically light iron in molar tooth structures to have been produced by microbial iron reduction utilising Fe-oxyhydroxides and smectites. The microbial conversion of smectite to illite results in a volume reduction of clay minerals ( 30%), while locally increasing pore water alkalinity. Therefore, this biogeochemical process is a viable mechanism to produce voids and subsequently precipitate carbonate minerals. The disappearance of molar tooth structures is likely linked to a combination of a decrease in smectite abundance, a decline in the marine DIC reservoir, and increase in the concentration of O2 in shallow seawater in the mid-Neoproterozoic.

  15. Small vessel disease, neurovascular regulation and cognitive impairment: post-mortem studies reveal a complex relationship, still poorly understood.

    PubMed

    Love, Seth; Miners, J Scott

    2017-07-15

    The contribution of vascular disease to cognitive impairment is under-recognized and the pathogenesis is poorly understood. This information gap has multiple causes, including a lack of post-mortem validation of clinical diagnoses of vascular cognitive impairment (VCI) or vascular dementia (VaD), the exclusion of cases with concomitant neurodegenerative disease when diagnosing VCI/VaD, and a lack of standardization of neuropathological assessment protocols for vascular disease. Other contributors include a focus on end-stage destructive lesions to the exclusion of more subtle types of diffuse brain injury, on structural abnormalities of arteries and arterioles to the exclusion of non-structural abnormalities and capillary damage, and the use of post-mortem sampling strategies that are biased towards the identification of neurodegenerative pathologies. Recent studies have demonstrated the value of detailed neuropathology in characterizing vascular contributions to cognitive impairment (e.g. in diabetes), and highlight the importance of diffuse white matter changes, capillary damage and vasoregulatory abnormalities in VCI/VaD. The use of standardized, evidence-based post-mortem assessment protocols and the inclusion of biochemical as well as morphological methods in neuropathological studies should improve the accuracy of determination of the contribution of vascular disease to cognitive impairment and clarify the relative contribution of different pathogenic processes to the tissue damage. © 2017 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  16. microRNA biogenesis and turnover in plants.

    PubMed

    Rogers, K; Chen, X

    2012-01-01

    microRNAs (miRNAs) are short RNAs that regulate gene expression in eukaryotes. The biogenesis and turnover of miRNAs determine their spatiotemporal accumulation within tissues. miRNA biogenesis is a multistep process that entails transcription, processing, nuclear export, and formation of the miRNA-ARGONAUTE complex. Factors that perform each of these steps have been identified. Generation of mature miRNAs from primary transcripts, i.e., miRNA processing, is a key step in miRNA biogenesis. Our understanding of miRNA processing has expanded beyond the enzyme that performs the reactions, as more and more additional factors that impact the efficiency and accuracy of miRNA processing are uncovered. In contrast to miRNA biogenesis, miRNA turnover is an important but poorly understood process that contributes to the steady-state levels of miRNAs. Enzymes responsible for miRNA degradation have only recently been identified. This review describes the processes of miRNA maturation and degradation in plants.

  17. Caregiver Burden Among Caregivers of Individuals With Severe Mental Illness: Testing the Moderation and Mediation Models of Resilience.

    PubMed

    Mulud, Zamzaliza Abdul; McCarthy, Geraldine

    2017-02-01

    The association between the socio-demographic characteristics of caregivers, such as gender and caregiver burden, is well documented; however, the process underlying this relationship is poorly understood. Based on the stress process model, we designed a cross-sectional study to examine the mediating and moderating effect of resilience on the relationship between gender and caregiver burden. Caregivers of individuals with severe mental illness (n=201) were recruited in two psychiatric outpatient clinics in Malaysia. The relationship between the gender of the caregiver and caregiver burden was mediated by resilience, thus supporting the stress process model. The findings from the present research contribute to the growing evidence of the interaction between socio-demographic variables of caregivers and resilience, and caregiver burden. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. GluA2-dependent AMPA receptor endocytosis and the decay of early and late long-term potentiation: possible mechanisms for forgetting of short- and long-term memories.

    PubMed

    Hardt, Oliver; Nader, Karim; Wang, Yu-Tian

    2014-01-05

    The molecular processes involved in establishing long-term potentiation (LTP) have been characterized well, but the decay of early and late LTP (E-LTP and L-LTP) is poorly understood. We review recent advances in describing the mechanisms involved in maintaining LTP and homeostatic plasticity. We discuss how these phenomena could relate to processes that might underpin the loss of synaptic potentiation over time, and how they might contribute to the forgetting of short-term and long-term memories. We propose that homeostatic downscaling mediates the loss of E-LTP, and that metaplastic parameters determine the decay rate of L-LTP, while both processes require the activity-dependent removal of postsynaptic GluA2-containing AMPA receptors.

  19. 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.

  20. Poor supplementary motor area activation differentiates auditory verbal hallucination from imagining the hallucination☆

    PubMed Central

    Raij, Tuukka T.; Riekki, Tapani J.J.

    2012-01-01

    Neuronal underpinnings of auditory verbal hallucination remain poorly understood. One suggested mechanism is brain activation that is similar to verbal imagery but occurs without the proper activation of the neuronal systems that are required to tag the origins of verbal imagery in one's mind. Such neuronal systems involve the supplementary motor area. The supplementary motor area has been associated with awareness of intention to make a hand movement, but whether this region is related to the sense of ownership of one's verbal thought remains poorly known. We hypothesized that the supplementary motor area is related to the distinction between one's own mental processing (auditory verbal imagery) and similar processing that is attributed to non-self author (auditory verbal hallucination). To test this hypothesis, we asked patients to signal the onset and offset of their auditory verbal hallucinations during functional magnetic resonance imaging. During non-hallucination periods, we asked the same patients to imagine the hallucination they had previously experienced. In addition, healthy control subjects signaled the onset and offset of self-paced imagery of similar voices. Both hallucinations and the imagery of hallucinations were associated with similar activation strengths of the fronto-temporal language-related circuitries, but the supplementary motor area was activated more strongly during the imagery than during hallucination. These findings suggest that auditory verbal hallucination resembles verbal imagery in language processing, but without the involvement of the supplementary motor area, which may subserve the sense of ownership of one's own verbal imagery. PMID:24179739

  1. Laboratory Astrophysics in Support of the Study of Nucleosynthesis

    NASA Astrophysics Data System (ADS)

    den Hartog, Betsy

    2017-04-01

    One of the outstanding questions in our understanding of the Universe is how the elements were made. Only a few of the lightest or primordial nuclei were made just after the Big Bang. Other light nuclei up to the iron (Fe)-group are made by fusion reactions in the interior of stars. Heavier nuclei are made primarily via neutron-capture events which are categorized as either slow or rapid, the s-process or r-process, respectively. Although s-process neutron-capture is fairly well understood, the r-process, which occurs in neutron dense (explosive) environments, remains more elusive. In recent years, progress has been made in the understanding of r-process nucleosynthesis through the study of elemental abundances in metal-poor stars. These stars, which are among the oldest objects in our Galaxy, contain a fossil record of the elemental mix of the surrounding interstellar medium when they formed. The improvement of both the accuracy and precision of elemental abundances in metal-poor stars has required a long-term effort to improve the necessary laboratory data - first for the rare earth elements and more recently for the Fe-group. In this talk I will describe our laboratory effort measuring atomic transition probabilities, which are determined from a combination of radiative lifetimes and emission branching fractions. I will then show some examples of the application of our laboratory data to the determination of metal-poor star elemental abundances and discuss insights that can be gleaned from these improved data. Work in collaboration with (and supported by) Jim Lawler (NSF Grant AST-1516182, NASA Grant NNX16AE96G), Chris Sneden (NSF Grant AST-1211585) and John Cowan (NSF Grant PHY-1430152 (JINA Center for the Evolution of the Elements)), among others.

  2. Modelling the Diversity of Outer Planetary Systems. 1; Formation and Evolution

    NASA Technical Reports Server (NTRS)

    Lissauer, J. J.; Levison, H. F.; Duncan, M. J.; Young, Richard E. (Technical Monitor)

    1998-01-01

    The process of planetary growth is extremely complicated, involving a myriad of physical and chemical processes, many of which are poorly understood. The ultimate configuration that a planetary system attains depends upon the properties of the disk out of which it grew, of the star at the center of the disk and, at least in some cases, of the interstellar environment. However, this dependence is poorly understood. Thus, in an effort to numerically survey the possible diversity of planetary systems, we have constructed synthetic systems of giant planets and integrated their orbits to determine the dynamical lifetimes and thus the viability of these systems. Our construction algorithm begins with 110 -- 180 planetesimals located between 4 and 40 AU from a one solar mass star; most initial planetesimals have masses several tenths that of Earth. We integrate the orbits of these bodies subject to mutual gravitational perturbations and gas drag for $10^6 - 10^7$ years, merging any pair of planetesimals which passed within one-tenth of a Hill Sphere of one another and adding "gas" to embryos larger than 10 Earth masses. Use of such large planetesimal radii provided sufficient damping to prevent the system from excessive dynamical heating. Subsequently, systems were evolved without gas drag, either with the inflated radii or with more realistic radii. Systems took from a few million years to greater than ten billion years to become stable ($10^9$ years without mergers of ejections). Some of the systems produced with the inflated radii closely resemble our Solar System. Encounters in simulations using realistic radii resulted in ejections, typically leaving only a few planets per system, most of which were in highly eccentric orbits. The structure and dynamics of the resulting "stable" systems is discussed in detail in the abstract by Levison et al.

  3. Right ventricular involution: What can we learn from nature's model of compensated hypertrophy?

    PubMed

    Bowen, Megan E; Liu, Xiaoqing; Sundwall, Peter M; Drakos, Stavros G; Li, Dean Y; Selzman, Craig H; McKellar, Stephen H

    2018-05-01

    Right ventricular (RV) failure (RVF) is a vexing problem facing patients with various disease processes and carries a high mortality. RVF is a poorly understood phenomenon with limited treatment options. In mammalian fetal circulation, the right ventricle is the systemic ventricle. In neonates, however, the left ventricle assumes that role and gradually thickens compared with the right ventricle. This process, known as right ventricular involution (RVI), is poorly understood. We sought to define the time course and identify mechanisms involved in RVI. Wild-type mice were bred and sacrificed on day of life (DOL) 1, 4, 8, 16, and 30 to evaluate left ventricular (LV) and RV wall thickness and apoptosis. A terminal deoxynucleotidyl transferase nick-end labeling assay and RNA sequencing were performed to measure changes during RVI. Morphometric analysis demonstrated the changes in RV and LV wall thickness occurring between DOL 1 and DOL 16 (RV:LV, 0.53:0.44; P = .03). In addition, apoptosis was most active early, with the highest percentage of apoptotic cells on DOL 1 (1.0%) and a significant decrease by DOL 30 (0.23%) (P = .02). Similarly, expression of the proapoptotic genes BCL2l11 and Pawr were increased at DOL 1, and the antiapoptotic genes Nol3 and Naip2 were significantly increased at DOL 30. RVI is a misnomer, but significant changes occur early (by DOL 16) in neonatal mouse hearts. Apoptosis plays a role in RVI, but whether manipulation of apoptotic pathways can prevent or reverse RVI is unknown and warrants further investigation. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  4. 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...

  5. 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…

  6. 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...

  7. Asian and Pacific Islander American Poverty: The Working Poor and the Jobless Poor.

    ERIC Educational Resources Information Center

    Toji, Dean S.; Johnson, James H.

    1992-01-01

    Assesses the incidence of Asian-American and Pacific Islander-American poverty, and offers a theoretical explanation for its existence. It is argued that poverty of Americans of Asian and Pacific Island descent is best understood in the context of the linkage of labor migration and U.S. labor market segmentation. (SLD)

  8. Activation of Corticostriatal Circuitry Relieves Chronic Neuropathic Pain

    PubMed Central

    Lee, Michelle; Manders, Toby R.; Eberle, Sarah E.; Su, Chen; D'amour, James; Yang, Runtao; Lin, Hau Yueh; Deisseroth, Karl; Froemke, Robert C.

    2015-01-01

    Neural circuits that determine the perception and modulation of pain remain poorly understood. The prefrontal cortex (PFC) provides top-down control of sensory and affective processes. While animal and human imaging studies have shown that the PFC is involved in pain regulation, its exact role in pain states remains incompletely understood. A key output target for the PFC is the nucleus accumbens (NAc), an important component of the reward circuitry. Interestingly, recent human imaging studies suggest that the projection from the PFC to the NAc is altered in chronic pain. The function of this corticostriatal projection in pain states, however, is not known. Here we show that optogenetic activation of the PFC produces strong antinociceptive effects in a rat model (spared nerve injury model) of persistent neuropathic pain. PFC activation also reduces the affective symptoms of pain. Furthermore, we show that this pain-relieving function of the PFC is likely mediated by projections to the NAc. Thus, our results support a novel role for corticostriatal circuitry in pain regulation. PMID:25834050

  9. Stochastic processes in gravitropism.

    PubMed

    Meroz, Yasmine; Bastien, Renaud

    2014-01-01

    In this short review we focus on the role of noise in gravitropism of plants - the reorientation of plants according to the direction of gravity. We briefly introduce the conventional picture of static gravisensing in cells specialized in sensing. This model hinges on the sedimentation of statoliths (high in density and mass relative to other organelles) to the lowest part of the sensing cell. We then present experimental observations that cannot currently be understood within this framework. Lastly we introduce some current alternative models and directions that attempt to incorporate and interpret these experimental observations, including: (i) dynamic sensing, where gravisensing is suggested to be enhanced by stochastic events due to thermal and mechanical noise. These events both effectively lower the threshold of response, and lead to small-distance sedimentation, allowing amplification, and integration of the signal. (ii) The role of the cytoskeleton in signal-to-noise modulation and (iii) in signal transduction. In closing, we discuss directions that seem to either not have been explored, or that are still poorly understood.

  10. Connecting marine ecosystem services to human well-being: insights from participatory well-being assessment in Kenya.

    PubMed

    Abunge, Caroline; Coulthard, Sarah; Daw, Tim M

    2013-12-01

    The linkage between ecosystems and human well-being is a focus of the conceptualization of "ecosystem services" as promoted by the Millennium Ecosystem Assessment. However, the actual nature of connections between ecosystems and the well-being of individuals remains complex and poorly understood. We conducted a series of qualitative focus groups with five different stakeholder groups connected to a small-scale Kenyan coastal fishery to understand (1) how well-being is understood within the community, and what is important for well-being, (2) how people's well-being has been affected by changes over the recent past, and (3) people's hopes and aspirations for their future fishery. Our results show that people conceive well-being in a diversity of ways, but that these can clearly map onto the MA framework. In particular, our research unpacks the "freedoms and choices" element of the framework and argues for greater recognition of these aspects of well-being in fisheries management in Kenya through, for example, more participatory governance processes.

  11. Mannose-pepstatin conjugates as targeted inhibitors of antigen processing.

    PubMed

    Free, Paul; Hurley, Christopher A; Kageyama, Takashi; Chain, Benjamin M; Tabor, Alethea B

    2006-05-07

    The molecular details of antigen processing, including the identity of the enzymes involved, their intracellular location and their substrate specificity, are still incompletely understood. Selective inhibition of proteolytic antigen processing enzymes such as cathepsins D and E, using small molecular inhibitors such as pepstatin, has proven to be a valuable tool in investigating these pathways. However, pepstatin is poorly soluble in water and has limited access to the antigen processing compartment in antigen presenting cells. We have synthesised mannose-pepstatin conjugates, and neomannosylated BSA-pepstatin conjugates, as tools for the in vivo study of the antigen processing pathway. Conjugation to mannose and to neomannosylated BSA substantially improved the solubility of the conjugates relative to pepstatin. The mannose-pepstatin conjugates showed no reduction in inhibition of cathepsin E, whereas the neomannosylated BSA-pepstatin conjugates showed some loss of inhibition, probably due to steric factors. However, a neomannosylated BSA-pepstatin conjugate incorporating a cleavable disulfide linkage between the pepstatin and the BSA showed the best uptake to dendritic cells and the best inhibition of antigen processing.

  12. Prevention of preterm birth: harnessing science to address the global epidemic.

    PubMed

    Rubens, Craig E; Sadovsky, Yoel; Muglia, Louis; Gravett, Michael G; Lackritz, Eve; Gravett, Courtney

    2014-11-12

    Preterm birth is a leading cause of infant morbidity and mortality worldwide, but current interventions to prevent prematurity are largely ineffective. Preterm birth is increasingly recognized as an outcome that can result from a variety of pathological processes. Despite current research efforts, the mechanisms underlying these processes remain poorly understood and are influenced by a range of biological and environmental factors. Research with modern techniques is needed to understand the mechanisms responsible for preterm labor and birth and identify targets for diagnostic and therapeutic solutions. This review evaluates the state of reproductive science relevant to understanding the causes of preterm birth, identifies potential targets for prevention, and outlines challenges and opportunities for translating research findings into effective interventions. Copyright © 2014, American Association for the Advancement of Science.

  13. Microbial community assembly and metabolic function during mammalian corpse decomposition

    USGS Publications Warehouse

    Metcalf, Jessica L; Xu, Zhenjiang Zech; Weiss, Sophie; Lax, Simon; Van Treuren, Will; Hyde, Embriette R.; Song, Se Jin; Amir, Amnon; Larsen, Peter; Sangwan, Naseer; Haarmann, Daniel; Humphrey, Greg C; Ackermann, Gail; Thompson, Luke R; Lauber, Christian; Bibat, Alexander; Nicholas, Catherine; Gebert, Matthew J; Petrosino, Joseph F; Reed, Sasha C.; Gilbert, Jack A; Lynne, Aaron M; Bucheli, Sibyl R; Carter, David O; Knight, Rob

    2016-01-01

    Vertebrate corpse decomposition provides an important stage in nutrient cycling in most terrestrial habitats, yet microbially mediated processes are poorly understood. Here we combine deep microbial community characterization, community-level metabolic reconstruction, and soil biogeochemical assessment to understand the principles governing microbial community assembly during decomposition of mouse and human corpses on different soil substrates. We find a suite of bacterial and fungal groups that contribute to nitrogen cycling and a reproducible network of decomposers that emerge on predictable time scales. Our results show that this decomposer community is derived primarily from bulk soil, but key decomposers are ubiquitous in low abundance. Soil type was not a dominant factor driving community development, and the process of decomposition is sufficiently reproducible to offer new opportunities for forensic investigations.

  14. Onset of frictional sliding of rubber–glass contact under dry and lubricated conditions

    PubMed Central

    Tuononen, Ari J.

    2016-01-01

    Rubber friction is critical in many applications ranging from automotive tyres to cylinder seals. The process where a static rubber sample transitions to frictional sliding is particularly poorly understood. The experimental and simulation results in this paper show a completely different detachment process from the static situation to sliding motion under dry and lubricated conditions. The results underline the contribution of the rubber bulk properties to the static friction force. In fact, simple Amontons’ law is sufficient as a local friction law to produce the correct detachment pattern when the rubber material and loading conditions are modelled properly. Simulations show that micro-sliding due to vertical loading can release initial shear stresses and lead to a high static/dynamic friction coefficient ratio, as observed in the measurements. PMID:27291939

  15. Recruitment of Mesenchymal Stem Cells Into Prostate Tumors Promotes Metastasis

    PubMed Central

    Jung, Younghun; Kim, Jin Koo; Shiozawa, Yusuke; Wang, Jingcheng; Mishra, Anjali; Joseph, Jeena; Berry, Janice E.; McGee, Samantha; Lee, Eunsohl; Sun, Hongli; Wang, Jianhua; Jin, Taocong; Zhang, Honglai; Dai, Jinlu; Krebsbach, Paul H.; Keller, Evan T.; Pienta, Kenneth J.; Taichman, Russell S.

    2013-01-01

    Tumors recruit mesenchymal stem cells (MSCs) to facilitate healing, which induces their conversion into cancer-associated fibroblasts that facilitate metastasis. However, this process is poorly understood on the molecular level. Here we show that the CXCR6 ligand CXCL16 facilitates MSC or Very Small Embryonic-Like (VSEL) cells recruitment into prostate tumors. CXCR6 signaling stimulates the conversion of MSCs into cancer-associated fibroblasts, which secrete stromal-derived factor-1, also known as CXCL12. CXCL12 expressed by cancer-associated fibroblasts then binds to CXCR4 on tumor cells and induces an epithelial to mesenchymal transition, which ultimately promotes metastasis to secondary tumor sites. Our results provide the molecular basis for MSC recruitment into tumors and how this process leads to tumor metastasis. PMID:23653207

  16. Modeling lung cancer evolution and preclinical response by orthotopic mouse allografts.

    PubMed

    Ambrogio, Chiara; Carmona, Francisco J; Vidal, August; Falcone, Mattia; Nieto, Patricia; Romero, Octavio A; Puertas, Sara; Vizoso, Miguel; Nadal, Ernest; Poggio, Teresa; Sánchez-Céspedes, Montserrat; Esteller, Manel; Mulero, Francisca; Voena, Claudia; Chiarle, Roberto; Barbacid, Mariano; Santamaría, David; Villanueva, Alberto

    2014-11-01

    Cancer evolution is a process that is still poorly understood because of the lack of versatile in vivo longitudinal studies. By generating murine non-small cell lung cancer (NSCLC) orthoallobanks and paired primary cell lines, we provide a detailed description of an in vivo, time-dependent cancer malignization process. We identify the acquisition of metastatic dissemination potential, the selection of co-driver mutations, and the appearance of naturally occurring intratumor heterogeneity, thus recapitulating the stochastic nature of human cancer development. This approach combines the robustness of genetically engineered cancer models with the flexibility of allograft methodology. We have applied this tool for the preclinical evaluation of therapeutic approaches. This system can be implemented to improve the design of future treatments for patients with NSCLC. ©2014 American Association for Cancer Research.

  17. Microbial community assembly and metabolic function during mammalian corpse decomposition

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

    Metcalf, J. L.; Xu, Z. Z.; Weiss, S.

    2015-12-10

    Vertebrate corpse decomposition provides an important stage in nutrient cycling in most terrestrial habitats, yet microbially mediated processes are poorly understood. Here we combine deep microbial community characterization, community-level metabolic reconstruction, and soil biogeochemical assessment to understand the principles governing microbial community assembly during decomposition of mouse and human corpses on different soil substrates. We find a suite of bacterial and fungal groups that contribute to nitrogen cycling and a reproducible network of decomposers that emerge on predictable time scales. Our results show that this decomposer community is derived primarily from bulk soil, but key decomposers are ubiquitous in lowmore » abundance. Soil type was not a dominant factor driving community development, and the process of decomposition is sufficiently reproducible to offer new opportunities for forensic investigations.« less

  18. NONFUEL MINERAL RESOURCES OF THE PACIFIC EXCLUSIVE ECONOMIC ZONE.

    USGS Publications Warehouse

    Clague, David; Bischoff, James; Howell, David

    1984-01-01

    The Pacific Exclusive Economic Zone contains a variety of hard mineral resources. Sand and gravel and their associated placer deposits of heavy minerals are the most likely to be developed in the near future, but offshore and deep water deposits of phosphorite, abyssal manganese nodules, ferromanganese crusts enriched in cobalt, and massive sulfide deposits all represent future resources. The distribution, extent, and formation of these deposits are poorly understood and will be clarified only with additional exploration, framework geologic mapping, and study of the processes by which these resources form. It is pointed out that the initial discovery of most hard-mineral resources in the EEZ was made during routine scientific marine-geologic surveys aimed at understanding the framework geology and geologic processes of an offshore region.

  19. 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.

  20. A PIONIER and Incisive Look at the Interacting Binary SS Lep

    NASA Astrophysics Data System (ADS)

    Blind, N.; Boffin, H. M. J.; Berger, J.-P.; Lebouquin, J.-B.; Mérand, A.

    2011-09-01

    Symbiotic stars are excellent laboratories to study a broad range of poorly understood physical processes, such as mass loss of red giants, accretion onto compact objects, and evolution of nova-like outbursts. As their evolution is strongly influenced by the mass transfer episodes, understanding the history of these systems requires foremost to determine which process is at play: Roche lobe overflow, stellar wind accretion, or some more complex mixture of both. We report here an interferometric study of the symbiotic system SS Leporis, performed with the unique PIONIER instrument. By determining the binary orbit and revisiting the parameters of the two stars, we show that the giant does not fill its Roche lobe, and that the mass transfer most likely occurs via the accretion of an important part of the giant's wind.

  1. Suppressing breakers with polar oil films: Using an epic sea rescue to model wave energy budgets

    NASA Astrophysics Data System (ADS)

    Cox, Charles S.; Zhang, Xin; Duda, Timothy F.

    2017-02-01

    Oil has been used to still stormy seas for centuries, but the mechanisms are poorly understood. Here we examine the processes by using quantitative information from a remarkable 1883 sea rescue where oil was used to reduce large breakers during a storm. Modeling of the oil film's extent and waves under the film suggests that large breakers were suppressed by a reduction of wind energy input. Modification of surface roughness by the film is hypothesized to alter the wind profile above the sea and the energy flow. The results are central to understanding air-sea momentum exchange, including its role in such processes as cyclone growth and storm surge, although they address only one aspect of the complex problem of wind interaction with the ocean surface.

  2. The rich get richer, the poor get even: Perceived socioeconomic position influences micro-social distributions of wealth.

    PubMed

    Bratanova, Boyka; Loughnan, Steve; Klein, Olivier; Wood, Robert

    2016-06-01

    Economic inequality has a robust negative effect on a range of important societal outcomes, including health, wellbeing, and education. Yet, it remains insufficiently understood why, how, and by whom unequal systems tend to be perpetuated. In two studies we examine whether psychological mindsets adopted by the wealthy and the poor in their micro-social transactions act to perpetuate or challenge inequality. We hypothesized that occupying a wealthier socioeconomic position promotes the pursuit of self-interest and contributes to inequality maintenance; poorer socioeconomic position, on the other hand, should promote the pursuit of fairness and equality restoration. In Study 1, participants completed an ultimatum game as proposers after being primed to believe they are wealthier or poorer, offering money to either poor or wealthy responders. As expected, the wealthy pursued their self-interest and the net effect of this behavior contributes to the maintenance of inequality. Conversely, the poor pursued fairness and the net effect of this behavior challenges inequality. In Study 2, participants were responders deciding whether to accept or reject unfair distributions. Compared to the wealthier, the poorer challenged inequality by rejecting unequal offers. The links between micro-social processes and macro-societal inequality are discussed. © 2016 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  3. Explanatory models of diabetes in urban poor communities in Accra, Ghana.

    PubMed

    de-Graft Aikins, Ama; Awuah, Raphael Baffour; Pera, Tuula Anneli; Mendez, Montserrat; Ogedegbe, Gbenga

    2015-01-01

    The objective of the study was to examine explanatory models of diabetes and diabetes complications among urban poor Ghanaians living with diabetes and implications for developing secondary prevention strategies. Twenty adults with type 2 diabetes were recruited from three poor communities in Accra. Qualitative data were obtained using interviews that run between 40 and 90 minutes. The interviews were audio-taped, transcribed and analysed thematically, informed by the 'explanatory model of disease' concept. Respondents associated diabetes and its complications with diet, family history, lifestyle factors (smoking, excessive alcohol consumption and physical inactivity), psychological stress and supernatural factors (witchcraft and sorcery). These associations were informed by biomedical and cultural models of diabetes and disease. Subjective experience, through a process of 'body-listening,' constituted a third model on which respondents drew to theorise diabetes complications. Poverty was an important mediator of poor self-care practices, including treatment non-adherence. The biomedical model of diabetes was a major source of legitimate information for self-care practices. However, this was understood and applied through a complex framework of cultural theories of chronic disease, the biopsychological impact of everyday illness experience and the disempowering effects of poverty. An integrated biopsychosocial approach is proposed for diabetes intervention in this research community.

  4. 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...

  5. New Insights into Glomerular Parietal Epithelial Cell Activation and Its Signaling Pathways in Glomerular Diseases

    PubMed Central

    Su, Hua; Chen, Shan; He, Fang-Fang; Wang, Yu-Mei; Bondzie, Philip; Zhang, Chun

    2015-01-01

    The glomerular parietal epithelial cells (PECs) have aroused an increasing attention recently. The proliferation of PECs is the main feature of crescentic glomerulonephritis; besides that, in the past decade, PEC activation has been identified in several types of noninflammatory glomerulonephropathies, such as focal segmental glomerulosclerosis, diabetic glomerulopathy, and membranous nephropathy. The pathogenesis of PEC activation is poorly understood; however, a few studies delicately elucidate the potential mechanisms and signaling pathways implicated in these processes. In this review we will focus on the latest observations and concepts about PEC activation in glomerular diseases and the newest identified signaling pathways in PEC activation. PMID:25866774

  6. Phase transitions and size scaling of membrane-less organelles

    PubMed Central

    2013-01-01

    The coordinated growth of cells and their organelles is a fundamental and poorly understood problem, with implications for processes ranging from embryonic development to oncogenesis. Recent experiments have shed light on the cell size–dependent assembly of membrane-less cytoplasmic and nucleoplasmic structures, including ribonucleoprotein (RNP) granules and other intracellular bodies. Many of these structures behave as condensed liquid-like phases of the cytoplasm/nucleoplasm. The phase transitions that appear to govern their assembly exhibit an intrinsic dependence on cell size, and may explain the size scaling reported for a number of structures. This size scaling could, in turn, play a role in cell growth and size control. PMID:24368804

  7. [Calcium hypothesis of Alzheimer disease].

    PubMed

    Riazantseva, M A; Mozhaeva, G N; Kaznacheeva, E V

    2012-01-01

    Alzheimer's disease is the most common neurodegenerative disorder characterized by progressive memory and cognitive abilities loss. The etiology of Alzheimer's disease is poorly understood. In this regard, there is no effective treatment for the disease. Various hypotheses to explain the nature of the pathology of Alzheimer's disease led to the development of appropriate therapeutics. Despite of decades of research and clinical trials available therapeutics, at best, can only slow down the progression of the disease, but cannot cure it. This review dedicated to the one of modern hypotheses of Alzheimer's disease pathogenesis implied the impairment of calcium homeostasis as a key event for the development of neurodegenerative processes.

  8. Manuscript peer review at the AJR: facts, figures, and quality assessment.

    PubMed

    Friedman, D P

    1995-04-01

    Concern by the government, funding institutions, and the public for quality assurance in all aspects of medical endeavors mandates critical examination of various professional activities. Although peer review is generally regarded as the best system for selecting and improving scientific papers for publication, the efficacy of this process has never been proved. Moreover, the administrative functions of the editorial staff are often poorly understood. The purpose of this article is to make peer review a the AJR less esoteric and more understandable by quantifying some of its activities. This information is then assessed as it relates to the quality of this important step in scientific publication.

  9. Reduction in the number of astrocytes and their projections is associated with increased synaptic protein density in the hypothalamus of poorly controlled diabetic rats.

    PubMed

    Lechuga-Sancho, Alfonso M; Arroba, Ana I; Frago, Laura M; García-Cáceres, Cristina; de Célix, Arancha Delgado-Rubín; Argente, Jesús; Chowen, Julie A

    2006-11-01

    Processes under hypothalamic control, such as thermogenesis, feeding behavior, and pituitary hormone secretion, are disrupted in poorly controlled diabetes, but the underlying mechanisms are poorly understood. Because glial cells regulate neurosecretory neurons through modulation of synaptic inputs and function, we investigated the changes in hypothalamic glia in rats with streptozotocin-induced diabetes mellitus. Hypothalamic glial fibrillary acidic protein (GFAP) levels decreased significantly 6 wk after diabetes onset. This was coincident with decreased GFAP immunoreactive surface area, astrocyte number, and the extension of GFAP immunoreactive processes/astrocyte in the arcuate nucleus. Cell death, analyzed by terminal deoxyuridine 5-triphosphate nick-end labeling and ELISA, increased significantly at 4 wk of diabetes. Proliferation, measured by Western blot for proliferating cell nuclear antigen and immunostaining for phosphorylated histone H-3, decreased in the hypothalamus of diabetic rats throughout the study, becoming significantly reduced by 8 wk. Both proliferation and death affected astroctyes because both phosphorylated histone H-3- and terminal deoxyuridine 5-triphosphate nick-end labeling-labeled cells were GFAP positive. Western blot analysis revealed that postsynaptic density protein 95 and the presynaptic proteins synapsin I and synaptotagmin increased significantly at 8 wk of diabetes, suggesting increased hypothalamic synaptic density. Thus, in poorly controlled diabetic rats, there is a decrease in the number of hypothalamic astrocytes that is correlated with modifications in synaptic proteins and possibly synaptic inputs. These morphological changes in the arcuate nucleus could be involved in neurosecretory and metabolic changes seen in diabetic animals.

  10. Risk-prone individuals prefer the wrong options on a rat version of the Iowa Gambling Task.

    PubMed

    Rivalan, Marion; Ahmed, Serge H; Dellu-Hagedorn, Françoise

    2009-10-15

    Decision making in complex and conflicting situations, as measured in the widely used Iowa Gambling Task (IGT), can be profoundly impaired in psychiatric disorders, such as attention-deficit/hyperactivity disorder, drug addiction, and also in healthy individuals for whom immediate gratification prevails over long-term gain. The cognitive processes underlying these deficits are poorly understood, in part due to a lack of suitable animal models assessing complex decision making with good construct validity. We developed a rat gambling task analogous to the IGT that tracks, for the first time, the ongoing decision process within a single session in an operant cage. Rats could choose between various options. Disadvantageous options, as opposed to advantageous ones, offered bigger immediate food reward but were followed by longer, unpredictable penalties (time-out). The majority of rats can evaluate and deduce favorable options more or less rapidly according to task complexity, whereas others systematically choose disadvantageously. These interindividual differences are stable over time and do not depend on task difficulty or on the level of food restriction. We find that poor decision making does not result from a failure to acquire relevant information but from hypersensitivity to reward and higher risk taking in anxiogenic situations. These results suggest that rats, as well as human poor performers, share similar traits to those observed in decision-making related psychiatric disorders. These traits could constitute risk factors of developing such disorders. The rapid identification of poor decision makers using the rat gambling task should promote the discovery of the specific brain dysfunctions that cause maladapted decision making.

  11. How does creating a concept map affect item-specific encoding?

    PubMed

    Grimaldi, Phillip J; Poston, Laurel; Karpicke, Jeffrey D

    2015-07-01

    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 words into categories, or creating a concept map. Memory was tested using a free recall test and a recognition memory test, which is considered to be especially sensitive to item-specific processing. Typically, tasks that promote item-specific processing enhance free recall of categorized lists, relative to category sorting. Concept mapping resulted in lower recall performance than both the pleasantness rating and category sorting condition for categorized words. Moreover, concept mapping resulted in lower recognition memory performance than the other 2 tasks. These results converge on the conclusion that creating a concept map disrupts the processing of item-specific information. (c) 2015 APA, all rights reserved.

  12. How Ag Nanospheres Are Transformed into AgAu Nanocages

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

    Moreau, Liane M.; Schurman, Charles A.; Kewalramani, Sumit

    Bimetallic hollow, porous noble metal nanoparticles are of broad interest for biomedical, optical and catalytic applications. The most straightforward method for preparing such structures involves the reaction between HAuCl4 and well-formed Ag particles, typically spheres, cubes, or triangular prisms, yet the mechanism underlying their formation is poorly understood at the atomic scale. By combining in situ nanoscopic and atomic-scale characterization techniques (XAFS, SAXS, XRF, and electron microscopy) to follow the process, we elucidate a plausible reaction pathway for the conversion of citrate-capped Ag nanospheres to AgAu nanocages; importantly, the hollowing event cannot be explained by the nanoscale Kirkendall effect, normore » by Galvanic exchange alone, two processes that have been previously proposed. We propose a modification of the bulk Galvanic exchange process that takes into account considerations that can only occur with nanoscale particles. This nanoscale Galvanic exchange process explains the novel morphological and chemical changes associated with the typically observed hollowing process.« less

  13. Differences in interfacial bond strengths of graphite fiber-epoxy resin composites

    NASA Technical Reports Server (NTRS)

    Needles, H. L.

    1985-01-01

    The effect of epoxy-size and degree of cure on the interfacial bonding of an epoxy-amine-graphite fiber composite system is examined. The role of the fiber-resin interface in determining the overall mechanical properties of composites is poorly understood. A good interfacial adhesive bond is required to achieve maximum stress transfer to the fibers in composites, but at the same time some form of energy absorbing interfacial interaction is needed to achieve high fracture toughening. The incompatibility of these two processes makes it important to understand the nature and basic factors involved at the fiber-resin interface as stress is applied. The mechanical properties including interlaminar shear values for graphite fiber-resin composites are low compared to glass and boron-resin composites. These differences have been attributed to poor fiber-matrix adhesion. Graphite fibers are commonly subjected to post-treatments including application of organic sizing in order to improve their compatibility with the resin matrix and to protect the fiber tow from damage during processing and lay-up. In such processes, sized graphite fiber tow is impregnated with epoxy resin and then layed-up i nto the appropriate configuration. Following an extended ambient temperature cure, the graphite-resin composite structure is cured at elevated temperature using a programmed temperature sequence to cure and then cool the product.

  14. Opponent appetitive-aversive neural processes underlie predictive learning of pain relief.

    PubMed

    Seymour, Ben; O'Doherty, John P; Koltzenburg, Martin; Wiech, Katja; Frackowiak, Richard; Friston, Karl; Dolan, Raymond

    2005-09-01

    Termination of a painful or unpleasant event can be rewarding. However, whether the brain treats relief in a similar way as it treats natural reward is unclear, and the neural processes that underlie its representation as a motivational goal remain poorly understood. We used fMRI (functional magnetic resonance imaging) to investigate how humans learn to generate expectations of pain relief. Using a pavlovian conditioning procedure, we show that subjects experiencing prolonged experimentally induced pain can be conditioned to predict pain relief. This proceeds in a manner consistent with contemporary reward-learning theory (average reward/loss reinforcement learning), reflected by neural activity in the amygdala and midbrain. Furthermore, these reward-like learning signals are mirrored by opposite aversion-like signals in lateral orbitofrontal cortex and anterior cingulate cortex. This dual coding has parallels to 'opponent process' theories in psychology and promotes a formal account of prediction and expectation during pain.

  15. Integrative analyses of human reprogramming reveal dynamic nature of induced pluripotency

    PubMed Central

    Cacchiarelli, Davide; Trapnell, Cole; Ziller, Michael J.; Soumillon, Magali; Cesana, Marcella; Karnik, Rahul; Donaghey, Julie; Smith, Zachary D.; Ratanasirintrawoot, Sutheera; Zhang, Xiaolan; Ho Sui, Shannan J.; Wu, Zhaoting; Akopian, Veronika; Gifford, Casey A.; Doench, John; Rinn, John L.; Daley, George Q.; Meissner, Alexander; Lander, Eric S.; Mikkelsen, Tarjei S.

    2015-01-01

    Summary Induced pluripotency is a promising avenue for disease modeling and therapy, but the molecular principles underlying this process, particularly in human cells, remain poorly understood due to donor-to-donor variability and intercellular heterogeneity. Here we constructed and characterized a clonal, inducible human reprogramming system that provides a reliable source of cells at any stage of the process. This system enabled integrative transcriptional and epigenomic analysis across the human reprogramming timeline at high resolution. We observed distinct waves of gene network activation, including the ordered reactivation of broad developmental regulators followed by early embryonic patterning genes and culminating in the emergence of a signature reminiscent of pre-implantation stages. Moreover, complementary functional analyses allowed us to identify and validate novel regulators of the reprogramming process. Altogether, this study sheds light on the molecular underpinnings of induced pluripotency in human cells and provides a robust cell platform for further studies. PMID:26186193

  16. Ultrafast dynamics of low-energy electron attachment via a non-valence correlation-bound state

    NASA Astrophysics Data System (ADS)

    Rogers, Joshua P.; Anstöter, Cate S.; Verlet, Jan R. R.

    2018-03-01

    The primary electron-attachment process in electron-driven chemistry represents one of the most fundamental chemical transformations with wide-ranging importance in science and technology. However, the mechanistic detail of the seemingly simple reaction of an electron and a neutral molecule to form an anion remains poorly understood, particularly at very low electron energies. Here, time-resolved photoelectron imaging was used to probe the electron-attachment process to a non-polar molecule using time-resolved methods. An initially populated diffuse non-valence state of the anion that is bound by correlation forces evolves coherently in ∼30 fs into a valence state of the anion. The extreme efficiency with which the correlation-bound state serves as a doorway state for low-energy electron attachment explains a number of electron-driven processes, such as anion formation in the interstellar medium and electron attachment to fullerenes.

  17. Pedophilic brain potential responses to adult erotic stimuli.

    PubMed

    Knott, Verner; Impey, Danielle; Fisher, Derek; Delpero, Emily; Fedoroff, Paul

    2016-02-01

    Cognitive mechanisms associated with the relative lack of sexual interest in adults by pedophiles are poorly understood and may benefit from investigations examining how the brain processes adult erotic stimuli. The current study used event-related brain potentials (ERP) to investigate the time course of the explicit processing of erotic, emotional, and neutral pictures in 22 pedophilic patients and 22 healthy controls. Consistent with previous studies, early latency anterior ERP components were highly selective for erotic pictures. Although the ERPs elicited by emotional stimuli were similar in patients and controls, an early frontal positive (P2) component starting as early as 185 ms was significantly attenuated and slow to onset in pedophilia, and correlated with a clinical measure of cognitive distortions. Failure of rapid attentional capture by erotic stimuli suggests a relative reduction in early processing in pedophilic patients which may be associated with relatively diminished sexual interest in adults. Copyright © 2016. Published by Elsevier B.V.

  18. Striatal BOLD Response Reflects the Impact of Herd Information on Financial Decisions

    PubMed Central

    Burke, Christopher J.; Tobler, Philippe N.; Schultz, Wolfram; Baddeley, Michelle

    2010-01-01

    Like other species, humans are sensitive to the decisions and actions of conspecifics, which can lead to herd behavior and undesirable outcomes such as stock market bubbles and bank runs. However, how the brain processes this socially derived influence is only poorly understood. Using functional magnetic resonance imaging (fMRI), we scanned participants as they made decisions on whether to buy stocks after observing others’ buying decisions. We demonstrate that activity in the ventral striatum, an area heavily implicated in reward processing, tracked the degree of influence on participants’ decisions arising from the observation of other peoples’ decisions. The signal did not track non-human, non-social control decisions. These findings lend weight to the notion that the ventral striatum is involved in the processing of complex social aspects of decision making and identify a possible neural basis for herd behavior. PMID:20589242

  19. Regulation of wound healing and fibrosis by hypoxia and hypoxia-inducible factor-1.

    PubMed

    Ruthenborg, Robin J; Ban, Jae-Jun; Wazir, Anum; Takeda, Norihiko; Kim, Jung-Whan

    2014-09-01

    Wound healing is a complex multi-step process that requires spatial and temporal orchestration of cellular and non-cellular components. Hypoxia is one of the prominent microenvironmental factors in tissue injury and wound healing. Hypoxic responses, mainly mediated by a master transcription factor of oxygen homeostasis, hypoxia-inducible factor-1 (HIF-1), have been shown to be critically involved in virtually all processes of wound healing and remodeling. Yet, mechanisms underlying hypoxic regulation of wound healing are still poorly understood. Better understanding of how the wound healing process is regulated by the hypoxic microenvironment and HIF-1 signaling pathway will provide insight into the development of a novel therapeutic strategy for impaired wound healing conditions such as diabetic wound and fibrosis. In this review, we will discuss recent studies illuminating the roles of HIF-1 in physiologic and pathologic wound repair and further, the therapeutic potentials of HIF-1 stabilization or inhibition.

  20. Current challenges in organic photovoltaic solar energy conversion.

    PubMed

    Schlenker, Cody W; Thompson, Mark E

    2012-01-01

    Over the last 10 years, significant interest in utilizing conjugated organic molecules for solid-state solar to electric conversion has produced rapid improvement in device efficiencies. Organic photovoltaic (OPV) devices are attractive for their compatibility with low-cost processing techniques and thin-film applicability to flexible and conformal applications. However, many of the processes that lead to power losses in these systems still remain poorly understood, posing a significant challenge for the future efficiency improvements required to make these devices an attractive solar technology. While semiconductor band models have been employed to describe OPV operation, a more appropriate molecular picture of the pertinent processes is beginning to emerge. This chapter presents mechanisms of OPV device operation, based on the bound molecular nature of the involved transient species. With the intention to underscore the importance of considering both thermodynamic and kinetic factors, recent progress in elucidating molecular characteristics that dictate photovoltage losses in heterojunction organic photovoltaics is also discussed.

  1. Large-Scale Fluorescence Calcium-Imaging Methods for Studies of Long-Term Memory in Behaving Mammals

    PubMed Central

    Jercog, Pablo; Rogerson, Thomas; Schnitzer, Mark J.

    2016-01-01

    During long-term memory formation, cellular and molecular processes reshape how individual neurons respond to specific patterns of synaptic input. It remains poorly understood how such changes impact information processing across networks of mammalian neurons. To observe how networks encode, store, and retrieve information, neuroscientists must track the dynamics of large ensembles of individual cells in behaving animals, over timescales commensurate with long-term memory. Fluorescence Ca2+-imaging techniques can monitor hundreds of neurons in behaving mice, opening exciting avenues for studies of learning and memory at the network level. Genetically encoded Ca2+ indicators allow neurons to be targeted by genetic type or connectivity. Chronic animal preparations permit repeated imaging of neural Ca2+ dynamics over multiple weeks. Together, these capabilities should enable unprecedented analyses of how ensemble neural codes evolve throughout memory processing and provide new insights into how memories are organized in the brain. PMID:27048190

  2. The multiple subfunctions of attention: differential developmental gateways to literacy and numeracy.

    PubMed

    Steele, Ann; Karmiloff-Smith, Annette; Cornish, Kim; Scerif, Gaia

    2012-11-01

    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 impact of distinct attention subfunctions on concurrent and longitudinal abilities related to literacy and numeracy. Distinct trajectories across attention measures revealed the emergence of 2 attentional factors, encompassing "executive" and "sustained-selective" processes. Executive attention predicted concurrent abilities across domains at Time 1, whereas sustained-selective attention predicted basic numeracy 1 year later. These concurrent and longitudinal constraints cast a broader light on the unfolding relations between domain-general and domain-specific processes over early childhood. © 2012 The Authors. Child Development © 2012 Society for Research in Child Development, Inc.

  3. Nanomechanics of Protein Unfolding outside Protease Nanopores

    NASA Astrophysics Data System (ADS)

    Luan, Binquan; Zhou, Ruhong

    Protein folding and unfolding have been the subject of active research for decades. Most of previous studies in protein unfolding were focused on temperature, chemical and/or force (such as in AFM) induced denaturations. Recent studies on the functional roles of proteasomes (such as ClpXP) revealed a novel unfolding process in cell, during which a target protein is mechanically unfolded and pulled into a confined, pore-like geometry for degradation. While the proteasome nanomachine has been extensively studied, the mechanism for unfolding proteins with the proteasome pore is still poorly understood. Here, we investigate the mechanical unfolding process of ubiquitin with (or really outside) an idealized proteasome pore, and compare such process with that in the AFM pulling experiment. Unexpectedly, the required force by a proteosome can be much smaller than that by the AFM. Simulation results also unveiled different nanomechanics, tearing fracture vs. shearing friction, in these two distinct types of mechanical unfoldings.

  4. 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

  5. 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 ...

  6. DNA replication-timing analysis of human chromosome 22 at high resolution and different developmental states.

    PubMed

    White, Eric J; Emanuelsson, Olof; Scalzo, David; Royce, Thomas; Kosak, Steven; Oakeley, Edward J; Weissman, Sherman; Gerstein, Mark; Groudine, Mark; Snyder, Michael; Schübeler, Dirk

    2004-12-21

    Duplication of the genome during the S phase of the cell cycle does not occur simultaneously; rather, different sequences are replicated at different times. The replication timing of specific sequences can change during development; however, the determinants of this dynamic process are poorly understood. To gain insights into the contribution of developmental state, genomic sequence, and transcriptional activity to replication timing, we investigated the timing of DNA replication at high resolution along an entire human chromosome (chromosome 22) in two different cell types. The pattern of replication timing was correlated with respect to annotated genes, gene expression, novel transcribed regions of unknown function, sequence composition, and cytological features. We observed that chromosome 22 contains regions of early- and late-replicating domains of 100 kb to 2 Mb, many (but not all) of which are associated with previously described chromosomal bands. In both cell types, expressed sequences are replicated earlier than nontranscribed regions. However, several highly transcribed regions replicate late. Overall, the DNA replication-timing profiles of the two different cell types are remarkably similar, with only nine regions of difference observed. In one case, this difference reflects the differential expression of an annotated gene that resides in this region. Novel transcribed regions with low coding potential exhibit a strong propensity for early DNA replication. Although the cellular function of such transcripts is poorly understood, our results suggest that their activity is linked to the replication-timing program.

  7. Evidence of current impact of climate change on life: a walk from genes to the biosphere.

    PubMed

    Peñuelas, Josep; Sardans, Jordi; Estiarte, Marc; Ogaya, Romà; Carnicer, Jofre; Coll, Marta; Barbeta, Adria; Rivas-Ubach, Albert; Llusià, Joan; Garbulsky, Martin; Filella, Iolanda; Jump, Alistair S

    2013-08-01

    We review the evidence of how organisms and populations are currently responding to climate change through phenotypic plasticity, genotypic evolution, changes in distribution and, in some cases, local extinction. Organisms alter their gene expression and metabolism to increase the concentrations of several antistress compounds and to change their physiology, phenology, growth and reproduction in response to climate change. Rapid adaptation and microevolution occur at the population level. Together with these phenotypic and genotypic adaptations, the movement of organisms and the turnover of populations can lead to migration toward habitats with better conditions unless hindered by barriers. Both migration and local extinction of populations have occurred. However, many unknowns for all these processes remain. The roles of phenotypic plasticity and genotypic evolution and their possible trade-offs and links with population structure warrant further research. The application of omic techniques to ecological studies will greatly favor this research. It remains poorly understood how climate change will result in asymmetrical responses of species and how it will interact with other increasing global impacts, such as N eutrophication, changes in environmental N : P ratios and species invasion, among many others. The biogeochemical and biophysical feedbacks on climate of all these changes in vegetation are also poorly understood. We here review the evidence of responses to climate change and discuss the perspectives for increasing our knowledge of the interactions between climate change and life. © 2013 John Wiley & Sons Ltd.

  8. Parental Decisions regarding pre-hospital therapy and costing of the Emergency Department Visit.

    PubMed

    McGovern, M; Kernan, R; O'Neill, M B

    2017-02-10

    Paediatric patients represent a large percentage of Emergency Department (ED) visits and there is often a perception that the acuity of these presentations is low. The decision-making process that results in parents attending the ED is poorly understood. We designed a cross-sectional cohort study to explore the reasons for attendance, the treatment initiated at home and to assess parental perception of the economic cost of attendance. Data was collected on 200 patients using a survey administered to parents in ED with a follow-up phone call 4-6 weeks later. Our results suggest that attendances are often prompted by parental anxiety rather than clinical deterioration and that prior ED usage is common among those presenting for assessment. Many parents had attempted community therapy with 128/200 patients (64%) having been referred by a healthcare professional and medical therapy at home having been employed by 114/200 (57%) parents before attendance. Parental knowledge of the safety of over-the-counter medications was variable the economic cost of an ED visit was poorly understood by participants. The results of our study suggest that parental desire for control over worrisome symptoms drives much of their management strategy prior to hospital attendance. Strategies in the ED may need to focus more on managing parental expectations than on managing the illness itself and management strategies employed should focus not only on medical therapy of the child's illness but on educating and empowering the parent.

  9. 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...

  10. Achieving Operability via the Mission System Paradigm

    NASA Technical Reports Server (NTRS)

    Hammer, Fred J.; Kahr, Joseph R.

    2006-01-01

    In the past, flight and ground systems have been developed largely-independently, with the flight system taking the lead, and dominating the development process. Operability issues have been addressed poorly in planning, requirements, design, I&T, and system-contracting activities. In many cases, as documented in lessons-learned, this has resulted in significant avoidable increases in cost and risk. With complex missions and systems, operability is being recognized as an important end-to-end design issue. Never-the-less, lessons-learned and operability concepts remain, in many cases, poorly understood and sporadically applied. A key to effective application of operability concepts is adopting a 'mission system' paradigm. In this paradigm, flight and ground systems are treated, from an engineering and management perspective, as inter-related elements of a larger mission system. The mission system consists of flight hardware, flight software, telecom services, ground data system, testbeds, flight teams, science teams, flight operations processes, procedures, and facilities. The system is designed in functional layers, which span flight and ground. It is designed in response to project-level requirements, mission design and an operations concept, and is developed incrementally, with early and frequent integration of flight and ground components.

  11. 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 ...

  12. Chemical trends in ocean islands explained by plume–slab interaction

    NASA Astrophysics Data System (ADS)

    Dannberg, Juliane; Gassmöller, Rene

    2018-04-01

    Earth's surface shows many features, of which the genesis can be understood only through their connection with processes in Earth's deep interior. Recent studies indicate that spatial geochemical patterns at oceanic islands correspond to structures in the lowermost mantle inferred from seismic tomographic models. This suggests that hot, buoyant upwellings can carry chemical heterogeneities from the deep lower mantle toward the surface, providing a window to the composition of the lowermost mantle. The exact nature of this link between surface and deep Earth remains debated and poorly understood. Using computational models, we show that subducted slabs interacting with dense thermochemical piles can trigger the ascent of hot plumes that inherit chemical gradients present in the lowermost mantle. We identify two key factors controlling this process: (i) If slabs induce strong lower-mantle flow toward the edges of these piles where plumes rise, the pile-facing side of the plume preferentially samples material originating from the pile, and bilaterally asymmetric chemical zoning develops. (ii) The composition of the melt produced reflects this bilateral zoning if the overlying plate moves roughly perpendicular to the chemical gradient in the plume conduit. Our results explain some of the observed geochemical trends of oceanic islands and provide insights into how these trends may originate.

  13. Multiscale analysis of information dynamics for linear multivariate processes.

    PubMed

    Faes, Luca; Montalto, Alessandro; Stramaglia, Sebastiano; Nollo, Giandomenico; Marinazzo, Daniele

    2016-08-01

    In the study of complex physical and physiological systems represented by multivariate time series, an issue of great interest is the description of the system dynamics over a range of different temporal scales. While information-theoretic approaches to the multiscale analysis of complex dynamics are being increasingly used, the theoretical properties of the applied measures are poorly understood. This study introduces for the first time a framework for the analytical computation of information dynamics for linear multivariate stochastic processes explored at different time scales. After showing that the multiscale processing of a vector autoregressive (VAR) process introduces a moving average (MA) component, we describe how to represent the resulting VARMA process using statespace (SS) models and how to exploit the SS model parameters to compute analytical measures of information storage and information transfer for the original and rescaled processes. The framework is then used to quantify multiscale information dynamics for simulated unidirectionally and bidirectionally coupled VAR processes, showing that rescaling may lead to insightful patterns of information storage and transfer but also to potentially misleading behaviors.

  14. Long-term priority effects among insects and fungi colonizing decaying wood.

    PubMed

    Weslien, Jan; Djupström, Line B; Schroeder, Martin; Widenfalk, Olof

    2011-11-01

    1. Priority effects have been hypothesized to have long-lasting impact on community structure in natural ecosystems. Long-term studies of priority effects in natural ecosystems are however sparse, especially in terrestrial ecosystems. 2. Wood decay is a slow process involving a high diversity of insect and fungus species. Species interactions that drive change in communities of insects and fungi during wood decay are poorly understood because of a lack of sufficient long-term studies. 3. In this paper, we followed the colonization and succession of wood-living insects and fungi on cut trees during 15 years, from tree death and onwards, in a boreal forest landscape. We test the long-term priority effects hypothesis that the identity and abundance of species that colonize first affect the colonization success of later-arriving species. We also hypothesize that species interact in both facilitative and inhibitory ways, which ultimately affect habitat quality for a red-listed late-succession beetle species. 4. Possible causal associations between species were explored by path analysis. The results indicate that one bark beetle species, Hylurgops palliatus, and one wood-borer species, Monochamus sutor, which colonized the wood during the first year after cutting, influenced the occurrence of a rare, wood-living beetle, Peltis grossa, that started to emerge from the stumps about 10 years later. The positive effects of Hylurgops palliatus and negative effects of M. sutor were largely mediated through the wood-decaying fungus species Fomitopsis pinicola. 5. The study shows that variable priority effects may have long-lasting impact on community assembly in decaying wood. The study also exemplifies new possibilities for managing populations of threatened species by exploring links between early, well-understood species guilds and late, more poorly understood species guilds. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

  15. Metaproteogenomics reveals the soil microbial communities active in nutrient cycling processes under different tree species

    NASA Astrophysics Data System (ADS)

    Keiblinger, Katharina Maria; Masse, Jacynthe; Zühlke, Daniela; Riedel, Katharina; Zechmeister-Boltenstern, Sophie; Prescott, Cindy E.; Grayston, Sue

    2016-04-01

    Tree species exert strong effects on microbial communities in litter and soil and may alter rates of soil processes fundamental to nutrient cycling and carbon fluxes (Prescott and Grayston 2013). However, the influence of tree species on decomposition processes are still contradictory and poorly understood. An understanding of the mechanisms underlying plant influences on soil processes is important for our ability to predict ecosystem response to altered global/environmental conditions. In order to link microbial community structure and function to forest-floor nutrient cycling processes, we sampled forest floors under western redcedar (Thuja plicata), Douglas-fir (Pseudotsuga menziesii) and Sitka spruce (Picea sitchensis) grown in nutrient-poor sites in common garden experiments on Vancouver island (Canada). We measured forest-floor total N, total C, initial NH4+ and NO3- concentrations, DOC, Cmic and Nmic. Gross rates of ammonification and NH4+ consumption were measured using the 15N pool-dilution method. Organic carbon quality was assessed through FTIR analyses. Microbial community structure was analysed by a metaproteogenomic approach using 16S and ITS amplification and sequencing with MiSeq platform. Proteins were extracted and peptides characterized via LC-MS/MS on a Velos Orbitrap to assess the active microbial community. Different microbial communities were active under the three tree species and variation in process rates were observed and will be discussed. This research provides new insights on microbial processes during organic matter decomposition. The metaproteogenomic approach enables us to investigate these changes with respect to possible effects on soil C-storage at even finer taxonomic resolution.

  16. Singlet Oxygen Formation during the Charging Process of an Aprotic Lithium-Oxygen Battery.

    PubMed

    Wandt, Johannes; Jakes, Peter; Granwehr, Josef; Gasteiger, Hubert A; Eichel, Rüdiger-A

    2016-06-06

    Aprotic lithium-oxygen (Li-O2 ) batteries have attracted considerable attention in recent years owing to their outstanding theoretical energy density. A major challenge is their poor reversibility caused by degradation reactions, which mainly occur during battery charge and are still poorly understood. Herein, we show that singlet oxygen ((1) Δg ) is formed upon Li2 O2 oxidation at potentials above 3.5 V. Singlet oxygen was detected through a reaction with a spin trap to form a stable radical that was observed by time- and voltage-resolved in operando EPR spectroscopy in a purpose-built spectroelectrochemical cell. According to our estimate, a lower limit of approximately 0.5 % of the evolved oxygen is singlet oxygen. The occurrence of highly reactive singlet oxygen might be the long-overlooked missing link in the understanding of the electrolyte degradation and carbon corrosion reactions that occur during the charging of Li-O2 cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Microbial metabolisms in a 2.5-km-deep ecosystem created by hydraulic fracturing in shales

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

    Daly, Rebecca A.; Borton, Mikayla A.; Wilkins, Michael J.

    Hydraulic fracturing is the industry standard for extracting hydrocarbons from shale formations. Attention has been paid to the economic benefits and environmental impacts of this process, yet the biogeochemical changes induced in the deep subsurface are poorly understood. Recent single-gene investigations revealed that halotolerant microbial communities were enriched after hydraulic fracturing. Here the reconstruction of 31 unique genomes coupled to metabolite data from the Marcellus and Utica shales revealed that methylamine cycling supports methanogenesis in the deep biosphere. Fermentation of injected chemical additives also sustains long-term microbial persistence, while sulfide generation from thiosulfate represents a poorly recognized corrosion mechanism inmore » shales. Extensive links between viruses and microbial hosts demonstrate active viral predation, which may contribute to the release of labile cellular constituents into the extracellular environment. Our analyses show that hydraulic fracturing provides the organismal and chemical inputs for colonization and persistence in the deep terrestrial subsurface.« less

  18. Medical management of ischemic stuttering priapism: a contemporary review of the literature.

    PubMed

    Levey, Helen R; Kutlu, Omer; Bivalacqua, Trinity J

    2012-01-01

    Priapism is defined as a prolonged and persistent erection of the penis without sexual stimulation. This is a poorly understood disease process with little information on the pathophysiology of this erectile disorder. Complications from this disorder are devastating due to the irreversible erectile damage and resultant erectile dysfunction (ED). Stuttering priapism, though relatively rare, affects a high prevalence of men with sickle-cell disease (SCD) and presents a challenging problem with guidelines for treatment lacking or resulting in permanent ED. The mechanisms involved in the development of priapism in this cohort are poorly characterized; therefore, medical management of priapism represents a therapeutic challenge to urologists. Additional research is warranted, so we can effectively target treatments for these patients with prevention as the goal. This review gives an introduction to stuttering priapism and its clinical significance, specifically with regards to the patient with SCD. Additionally, the proposed mechanisms behind its pathophysiology and a summary of the current and future targets for medical management are discussed.

  19. A Qualitative Systematic Review of the Bereavement Process Following Suicide.

    PubMed

    Shields, Chris; Kavanagh, Michele; Russo, Kate

    2017-03-01

    Despite the fact that a large number of people are bereaved by suicide each year, the experiences of those bereaved by suicide are poorly understood. It has been suggested that a contributing factor in relation to this lack of understanding has been the use of quantitative methods, which may not be sensitive to the bereavement process and its thematic content. Therefore, the current article outlines a systematic review of 11 qualitative studies that address issues related to the bereavement process following suicide. The results indicate that those bereaved by suicide encounter a range of difficult feelings following suicide including blame, guilt, and emptiness and that these feelings are affected by participants' ability to make meaning of the event. The meaning-making process is a complex one that occurs within a difficult social context in which both those bereaved by suicide and members of the wider community struggle to interact with each other in a beneficial way. Clinical implications of these findings are discussed.

  20. Enhancement of MS Signal Processing For Improved Cancer Biomarker Discovery

    NASA Astrophysics Data System (ADS)

    Si, Qian

    Technological advances in proteomics have shown great potential in detecting cancer at the earliest stages. One way is to use the time of flight mass spectroscopy to identify biomarkers, or early disease indicators related to the cancer. Pattern analysis of time of flight mass spectra data from blood and tissue samples gives great hope for the identification of potential biomarkers among the complex mixture of biological and chemical samples for the early cancer detection. One of the keys issues is the pre-processing of raw mass spectra data. A lot of challenges need to be addressed: unknown noise character associated with the large volume of data, high variability in the mass spectroscopy measurements, and poorly understood signal background and so on. This dissertation focuses on developing statistical algorithms and creating data mining tools for computationally improved signal processing for mass spectrometry data. I have introduced an advanced accurate estimate of the noise model and a half-supervised method of mass spectrum data processing which requires little knowledge about the data.

  1. The nature of short-term consolidation in visual working memory.

    PubMed

    Ricker, Timothy J; Hardman, Kyle O

    2017-11-01

    Short-term consolidation is the process by which stable working memory representations are created. This process is fundamental to cognition yet poorly understood. The present work examines short-term consolidation using a Bayesian hierarchical model of visual working memory recall to determine the underlying processes at work. Our results show that consolidation functions largely through changing the proportion of memory items successfully maintained until test. Although there was some evidence that consolidation affects representational precision, this change was modest and could not account for the bulk of the consolidation effect on memory performance. The time course of the consolidation function and selective influence of consolidation on specific serial positions strongly indicates that short-term consolidation induces an attentional blink. The blink leads to deficits in memory for the immediately following item when time pressure is introduced. Temporal distinctiveness accounts of the consolidation process are tested and ruled out. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  2. Analytic cognitive style, not delusional ideation, predicts data gathering in a large beads task study.

    PubMed

    Ross, Robert M; Pennycook, Gordon; McKay, Ryan; Gervais, Will M; Langdon, Robyn; Coltheart, Max

    2016-07-01

    It has been proposed that deluded and delusion-prone individuals gather less evidence before forming beliefs than those who are not deluded or delusion-prone. The primary source of evidence for this "jumping to conclusions" (JTC) bias is provided by research that utilises the "beads task" data-gathering paradigm. However, the cognitive mechanisms subserving data gathering in this task are poorly understood. In the largest published beads task study to date (n = 558), we examined data gathering in the context of influential dual-process theories of reasoning. Analytic cognitive style (the willingness or disposition to critically evaluate outputs from intuitive processing and engage in effortful analytic processing) predicted data gathering in a non-clinical sample, but delusional ideation did not. The relationship between data gathering and analytic cognitive style suggests that dual-process theories of reasoning can contribute to our understanding of the beads task. It is not clear why delusional ideation was not found to be associated with data gathering or analytic cognitive style.

  3. 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.

  4. Context processing in adolescents with autism spectrum disorder: How complex could it be?

    PubMed

    Ben-Yosef, Dekel; Anaki, David; Golan, Ofer

    2017-03-01

    The ability of individuals with Autism Spectrum Disorder (ASD) to process context has long been debated: According to the Weak Central Coherence theory, ASD is characterized by poor global processing, and consequently-poor context processing. In contrast, the Social Cognition theory argues individuals with ASD will present difficulties only in social context processing. The complexity theory of autism suggests context processing in ASD will depend on task complexity. The current study examined this controversy through two priming tasks, one presenting human stimuli (facial expressions) and the other presenting non-human stimuli (animal faces). Both tasks presented visual targets, preceded by congruent, incongruent, or neutral auditory primes. Local and global processing were examined by presenting the visual targets in three spatial frequency conditions: High frequency, low frequency, and broadband. Tasks were administered to 16 adolescents with high functioning ASD and 16 matched typically developing adolescents. Reaction time and accuracy were measured for each task in each condition. Results indicated that individuals with ASD processed context for both human and non-human stimuli, except in one condition, in which human stimuli had to be processed globally (i.e., target presented in low frequency). The task demands presented in this condition, and the performance deficit shown in the ASD group as a result, could be understood in terms of cognitive overload. These findings provide support for the complexity theory of autism and extend it. Our results also demonstrate how associative priming could support intact context processing of human and non-human stimuli in individuals with ASD. Autism Res 2017, 10: 520-530. © 2016 International Society for Autism Research, Wiley Periodicals, Inc. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

  5. Surface tension propulsion of fungal spores by use of microdroplets

    NASA Astrophysics Data System (ADS)

    Noblin, Xavier; Yang, Sylvia; Dumais, Jacques

    2010-11-01

    Most basidiomycete fungi (such as edible mushrooms) actively eject their spores. The process begins with the condensation of a water droplet at the base of the spore. The fusion of the droplet onto the spore creates a momentum that propels the spore forward. The use of surface tension for spore ejection offers a new paradigm to perform work at small length scales. However, this mechanism of force generation remains poorly understood. To elucidate how fungal spores make effective use of surface tension, we performed high-speed video imaging of spore ejection in Auricularia auricula and Sporobolomyces yeast, along with a detailed mechanical analysis of the spore ejection. We developed an explicit relation for the conversion of surface energy into kinetic energy during the coalescence process. The relation was validated with a simple artificial system.

  6. Systemic localization of seven major types of carbohydrates on cell membranes by dSTORM imaging.

    PubMed

    Chen, Junling; Gao, Jing; Zhang, Min; Cai, Mingjun; Xu, Haijiao; Jiang, Junguang; Tian, Zhiyuan; Wang, Hongda

    2016-07-25

    Carbohydrates on the cell surface control intercellular interactions and play a vital role in various physiological processes. However, their systemic distribution patterns are poorly understood. Through the direct stochastic optical reconstruction microscopy (dSTORM) strategy, we systematically revealed that several types of representative carbohydrates are found in clustered states. Interestingly, the results from dual-color dSTORM imaging indicate that these carbohydrate clusters are prone to connect with one another and eventually form conjoined platforms where different functional glycoproteins aggregate (e.g., epidermal growth factor receptor, (EGFR) and band 3 protein). A thorough understanding of the ensemble distribution of carbohydrates on the cell surface paves the way for elucidating the structure-function relationship of cell membranes and the critical roles of carbohydrates in various physiological and pathological cell processes.

  7. Elevated arousal levels enhance contrast perception.

    PubMed

    Kim, Dongho; Lokey, Savannah; Ling, Sam

    2017-02-01

    Our state of arousal fluctuates from moment to moment-fluctuations that can have profound impacts on behavior. Arousal has been proposed to play a powerful, widespread role in the brain, influencing processes as far ranging as perception, memory, learning, and decision making. Although arousal clearly plays a critical role in modulating behavior, the mechanisms underlying this modulation remain poorly understood. To address this knowledge gap, we examined the modulatory role of arousal on one of the cornerstones of visual perception: contrast perception. Using a reward-driven paradigm to manipulate arousal state, we discovered that elevated arousal state substantially enhances visual sensitivity, incurring a multiplicative modulation of contrast response. Contrast defines vision, determining whether objects appear visible or invisible to us, and these results indicate that one of the consequences of decreased arousal state is an impaired ability to visually process our environment.

  8. GABAergic interneurons: The orchestra or the conductor in fear learning and memory?

    PubMed

    Lucas, Elizabeth K; Clem, Roger L

    2017-12-02

    Fear conditioning is a form of associative learning that is fundamental to survival and involves potentiation of activity in excitatory projection neurons (PNs). Current models stipulate that the mechanisms underlying this process involve plasticity of PN synapses, which exhibit strengthening in response to fear conditioning. However, excitatory PNs are extensively modulated by a diverse array of GABAergic interneurons whose contributions to acquisition, storage, and expression of fear memory remain poorly understood. Here we review emerging evidence that genetically-defined interneurons play important subtype-specific roles in processing of fear-related stimuli and that these dynamics shape PN firing through both inhibition and disinhibition. Furthermore, interneurons exhibit structural, molecular, and electrophysiological evidence of fear learning-induced synaptic plasticity. These studies warrant discarding the notion of interneurons as passive bystanders in long-term memory. Copyright © 2017. Published by Elsevier Inc.

  9. Towards Mechanistic Understanding of Mercury Availability and Toxicity to Aquatic Primary Producers.

    PubMed

    Dranguet, Perrine; Flück, Rebecca; Regier, Nicole; Cosio, Claudia; Le Faucheur, Séverine; Slaveykova, Vera I

    2014-11-01

    The present article reviews current knowledge and recent progress on the bioavailability and toxicity of mercury to aquatic primary producers. Mercury is a ubiquitous toxic trace element of global concern. At the base of the food web, primary producers are central for mercury incorporation into the food web. Here, the emphasis is on key, but still poorly understood, processes governing the interactions between mercury species and phytoplankton, and macrophytes, two representatives of primary producers. Mass transfer to biota surface, adsorption to cell wall, internalization and release from cells, as well as underlying toxicity mechanisms of both inorganic mercury and methylmercury are discussed critically. In addition, the intracellular distribution and transformation processes, their importance for mercury toxicity, species-sensitivity differences and trophic transfer are presented. The mini-review is illustrated with examples of our own research.

  10. Associative fear learning and perceptual discrimination: a perceptual pathway in the development of chronic pain.

    PubMed

    Zaman, Jonas; Vlaeyen, Johan W S; Van Oudenhove, Lukas; Wiech, Katja; Van Diest, Ilse

    2015-04-01

    Recent neuropsychological theories emphasize the influence of maladaptive learning and memory processes on pain perception. However, the precise relationship between these processes as well as the underlying mechanisms remain poorly understood; especially the role of perceptual discrimination and its modulation by associative fear learning has received little attention so far. Experimental work with exteroceptive stimuli consistently points to effects of fear learning on perceptual discrimination acuity. In addition, clinical observations have revealed that in individuals with chronic pain perceptual discrimination is impaired, and that tactile discrimination training reduces pain. Based on these findings, we present a theoretical model of which the central tenet is that associative fear learning contributes to the development of chronic pain through impaired interoceptive and proprioceptive discrimination acuity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. The Emerging Importance of IgG Fab Glycosylation in Immunity.

    PubMed

    van de Bovenkamp, Fleur S; Hafkenscheid, Lise; Rispens, Theo; Rombouts, Yoann

    2016-02-15

    Human IgG is the most abundant glycoprotein in serum and is crucial for protective immunity. In addition to conserved IgG Fc glycans, ∼15-25% of serum IgG contains glycans within the variable domains. These so-called "Fab glycans" are primarily highly processed complex-type biantennary N-glycans linked to N-glycosylation sites that emerge during somatic hypermutation. Specific patterns of Fab glycosylation are concurrent with physiological and pathological conditions, such as pregnancy and rheumatoid arthritis. With respect to function, Fab glycosylation can significantly affect stability, half-life, and binding characteristics of Abs and BCRs. Moreover, Fab glycans are associated with the anti-inflammatory activity of IVIgs. Consequently, IgG Fab glycosylation appears to be an important, yet poorly understood, process that modulates immunity. Copyright © 2016 by The American Association of Immunologists, Inc.

  12. Sand dune effects on seismic data

    NASA Astrophysics Data System (ADS)

    Arran, M.; Vriend, N. M.; Muyzert, E. J.

    2017-12-01

    Ground roll is a significant source of noise in land seismic data, with cross-line scattered ground roll particularly difficult to suppress. This noise arises from surface heterogeneities lateral to the receiver spread, and in desert regions sand dunes are a major contributor. However, the nature of this noise is poorly understood, preventing the design of more effective data acquisition or processing techniques. Here, we present numerical simulations demonstrating that sand dunes can act as resonators, scattering a seismic signal over an extensive period of time. We introduce a mathematical framework that quantitatively describes the properties of noise scattered by a barchan dune, and we discuss the relevance of heterogeneities within the dune. Having identified regions in time, space, and frequency space at which noise will be more significant, we propose the possibility of reducing dune-scattered noise through careful survey design and data processing.

  13. Systemic localization of seven major types of carbohydrates on cell membranes by dSTORM imaging

    PubMed Central

    Chen, Junling; Gao, Jing; Zhang, Min; Cai, Mingjun; Xu, Haijiao; Jiang, Junguang; Tian, Zhiyuan; Wang, Hongda

    2016-01-01

    Carbohydrates on the cell surface control intercellular interactions and play a vital role in various physiological processes. However, their systemic distribution patterns are poorly understood. Through the direct stochastic optical reconstruction microscopy (dSTORM) strategy, we systematically revealed that several types of representative carbohydrates are found in clustered states. Interestingly, the results from dual-color dSTORM imaging indicate that these carbohydrate clusters are prone to connect with one another and eventually form conjoined platforms where different functional glycoproteins aggregate (e.g., epidermal growth factor receptor, (EGFR) and band 3 protein). A thorough understanding of the ensemble distribution of carbohydrates on the cell surface paves the way for elucidating the structure-function relationship of cell membranes and the critical roles of carbohydrates in various physiological and pathological cell processes. PMID:27453176

  14. Palaeontological evidence of membrane relationship in step-by-step membrane fusion

    PubMed Central

    WANG, XIN; LIU, WENZHE; DU, KAIHE

    2011-01-01

    Studies on membrane fusion in living cells indicate that initiation of membrane fusion is a transient and hard to capture process. Despite previous research, membrane behaviour at this point is still poorly understood. Recent palaeobotanical research has revealed snapshots of membrane fusion in a 15-million-year-old fossil pinaceous cone. To reveal the membrane behaviour during the fusion, we conducted more observations on the same fossil material. Several discernible steps of membrane fusion have been fixed naturally and observed in the fossil material. This observation provides transmission electron microscope (TEM) images of the transient intermediate stage and clearly shows the relationship between membranes. Observing such a transient phenomenon in fossil material implies that the fixing was most likely accomplished quickly by a natural process. The mechanism behind this phenomenon is clearly worthy of further enquiry. PMID:21190428

  15. Microbial community assembly and metabolic function during mammalian corpse decomposition.

    PubMed

    Metcalf, Jessica L; Xu, Zhenjiang Zech; Weiss, Sophie; Lax, Simon; Van Treuren, Will; Hyde, Embriette R; Song, Se Jin; Amir, Amnon; Larsen, Peter; Sangwan, Naseer; Haarmann, Daniel; Humphrey, Greg C; Ackermann, Gail; Thompson, Luke R; Lauber, Christian; Bibat, Alexander; Nicholas, Catherine; Gebert, Matthew J; Petrosino, Joseph F; Reed, Sasha C; Gilbert, Jack A; Lynne, Aaron M; Bucheli, Sibyl R; Carter, David O; Knight, Rob

    2016-01-08

    Vertebrate corpse decomposition provides an important stage in nutrient cycling in most terrestrial habitats, yet microbially mediated processes are poorly understood. Here we combine deep microbial community characterization, community-level metabolic reconstruction, and soil biogeochemical assessment to understand the principles governing microbial community assembly during decomposition of mouse and human corpses on different soil substrates. We find a suite of bacterial and fungal groups that contribute to nitrogen cycling and a reproducible network of decomposers that emerge on predictable time scales. Our results show that this decomposer community is derived primarily from bulk soil, but key decomposers are ubiquitous in low abundance. Soil type was not a dominant factor driving community development, and the process of decomposition is sufficiently reproducible to offer new opportunities for forensic investigations. Copyright © 2016, American Association for the Advancement of Science.

  16. 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...

  17. 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

  18. 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...

  19. Biological Niches within Human Calcified Aortic Valves: Towards Understanding of the Pathological Biomineralization Process

    PubMed Central

    Cottignoli, Valentina; Agrosì, Giovanna; Familiari, Giuseppe; Salvador, Loris

    2015-01-01

    Despite recent advances, mineralization site, its microarchitecture, and composition in calcific heart valve remain poorly understood. A multiscale investigation, using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectrometry (EDS), from micrometre up to nanometre, was conducted on human severely calcified aortic and mitral valves, to provide new insights into calcification process. Our aim was to evaluate the spatial relationship existing between bioapatite crystals, their local growing microenvironment, and the presence of a hierarchical architecture. Here we detected the presence of bioapatite crystals in two different mineralization sites that suggest the action of two different growth processes: a pathological crystallization process that occurs in biological niches and is ascribed to a purely physicochemical process and a matrix-mediated mineralized process in which the extracellular matrix acts as the template for a site-directed nanocrystals nucleation. Different shapes of bioapatite crystallization were observed at micrometer scale in each microenvironment but at the nanoscale level crystals appear to be made up by the same subunits. PMID:26509159

  20. Antigen Masking During Fixation and Embedding, Dissected

    PubMed Central

    Scalia, Carla Rossana; Boi, Giovanna; Bolognesi, Maddalena Maria; Riva, Lorella; Manzoni, Marco; DeSmedt, Linde; Bosisio, Francesca Maria; Ronchi, Susanna; Leone, Biagio Eugenio; Cattoretti, Giorgio

    2016-01-01

    Antigen masking in routinely processed tissue is a poorly understood process caused by multiple factors. We sought to dissect the effect on antigenicity of each step of processing by using frozen sections as proxies of the whole tissue. An equivalent extent of antigen masking occurs across variable fixation times at room temperature. Most antigens benefit from longer fixation times (>24 hr) for optimal detection after antigen retrieval (AR; for example, Ki-67, bcl-2, ER). The transfer to a graded alcohol series results in an enhanced staining effect, reproduced by treating the sections with detergents, possibly because of a better access of the polymeric immunohistochemical detection system to tissue structures. A second round of masking occurs upon entering the clearing agent, mostly at the paraffin embedding step. This may depend on the non-freezable water removal. AR fully reverses the masking due both to the fixation time and the paraffin embedding. AR itself destroys some epitopes which do not survive routine processing. Processed frozen sections are a tool to investigate fixation and processing requirements for antigens in routine specimens. PMID:27798289

  1. Sw1644+57: a relativistic jet that switched on and is now switching off

    NASA Astrophysics Data System (ADS)

    Tanvir, Nial

    2011-09-01

    Sw-J1644+57 was detected as a long-lived gamma-ray outburst in Mar 2011. Its unique H-E properties and location in the nucleus of a small galaxy at z=0.35, suggested it was due to the tidal disruption of a star by a 1-10 million Mo black-hole producing a relativistic jet. The super-Eddington luminosity is understood by the jet pointing towards us. Subsequent monitoring has shown the emission to decline roughly at the expected -5/3 power-law for TDE fall-back, till a few weeks ago when it abruptly "switched off". Our recent XMM data fixes the decline to be a factor ~100 over only ~60d. Such a rapid shut-down of accretion (~t^-25) seems implausible, so likely it represents the jet launching mechanism turning off. We request a CXO observation, several weeks after the XMM visit, to to establish whether the flux continues to decline, or stabilises at a low level (eg. due to emission directly from the accretion disk), thus shedding light on the poorly understood process of jet production.

  2. Effects of post-encoding stress on performance in the DRM false memory paradigm

    PubMed Central

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

    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 memory task) and memory was tested 24 h later. Stress decreased recognition of studied words, while increasing false recognition of semantically related lure words. Moreover, while control subjects remembered true and false words equivalently, stressed subjects remembered more false than true words. These results suggest that stress supports gist memory formation in the DRM task, perhaps by hindering detail-specific processing in the hippocampus. PMID:26670187

  3. Adult Mouse Cortical Cell Taxonomy by Single Cell Transcriptomics

    PubMed Central

    Tasic, Bosiljka; Menon, Vilas; Nguyen, Thuc Nghi; Kim, Tae Kyung; Jarsky, Tim; Yao, Zizhen; Levi, Boaz; Gray, Lucas T.; Sorensen, Staci A.; Dolbeare, Tim; Bertagnolli, Darren; Goldy, Jeff; Shapovalova, Nadiya; Parry, Sheana; Lee, Changkyu; Smith, Kimberly; Bernard, Amy; Madisen, Linda; Sunkin, Susan M.; Hawrylycz, Michael; Koch, Christof; Zeng, Hongkui

    2016-01-01

    Nervous systems are composed of various cell types, but the extent of cell type diversity is poorly understood. Here, we construct a cellular taxonomy of one cortical region, primary visual cortex, in adult mice based on single cell RNA-sequencing. We identify 49 transcriptomic cell types including 23 GABAergic, 19 glutamatergic and seven non-neuronal types. We also analyze cell-type specific mRNA processing and characterize genetic access to these transcriptomic types by many transgenic Cre lines. Finally, we show that some of our transcriptomic cell types display specific and differential electrophysiological and axon projection properties, thereby confirming that the single cell transcriptomic signatures can be associated with specific cellular properties. PMID:26727548

  4. Vital effects in coral skeletal composition display strict three-dimensional control

    USGS Publications Warehouse

    Meibom, A.; Yurimoto, H.; Cuif, J.-P.; Domart-Coulon, I.; Houlbreque, F.; Constantz, B.; Dauphin, Y.; Tambutte, E.; Tambutte, S.; Allemand, D.; Wooden, J.; Dunbar, R.

    2006-01-01

    Biological control over coral skeletal composition is poorly understood but critically important to paleoenvironmental reconstructions. We present microanalytical measurements of trace-element abundances as well as oxygen and carbon isotopic compositions of individual skeletal components in the zooxanthellate coral Colpophyllia sp. Our data show that centers of calcification (COC) have higher trace element concentrations and distinctly lighter isotopic compositions than the fibrous components of the skeleton. These observations necessitate that COC and the fibrous skeleton are precipitated by different mechanisms, which are controlled by specialized domains of the calicoblastic cell-layer. Biological processes control the composition of the skeleton even at the ultra-structure level. Copyright 2006 by the American Geophysical Union.

  5. The Role of Histone Deacetylases in Neurodegenerative Diseases and Small-Molecule Inhibitors as a Potential Therapeutic Approach

    NASA Astrophysics Data System (ADS)

    Bürli, Roland W.; Thomas, Elizabeth; Beaumont, Vahri

    Neurodegenerative disorders are devastating for patients and their social environment. Their etiology is poorly understood and complex. As a result, there is clearly an urgent need for therapeutic agents that slow down disease progress and alleviate symptoms. In this respect, interference with expression and function of multiple gene products at the epigenetic level has offered much promise, and histone deacetylases play a crucial role in these processes. This review presents an overview of the biological pathways in which these enzymes are involved and illustrates the complex network of proteins that governs their activity. An overview of small molecules that interfere with histone deacetylase function is provided.

  6. Pivotal response treatment prompts a functional rewiring of the brain among individuals with autism spectrum disorder.

    PubMed

    Venkataraman, Archana; Yang, Daniel Y-J; Dvornek, Nicha; Staib, Lawrence H; Duncan, James S; Pelphrey, Kevin A; Ventola, Pamela

    2016-09-28

    Behavioral interventions for autism have gained prominence in recent years; however, the neural-systems-level targets of these interventions remain poorly understood. We use a novel Bayesian framework to extract network-based differences before and after a 16-week pivotal response treatment (PRT) regimen. Our results suggest that the functional changes induced by PRT localize to the posterior cingulate and are marked by a shift in connectivity from the orbitofrontal cortex to the occipital-temporal cortex. Our results illuminate a potential PRT-induced learning mechanism, whereby the neural circuits involved during social perception shift from sensory and attentional systems to higher-level object and face processing areas.

  7. Pivotal Response Treatment Prompts a Functional Rewiring of the Brain amongst Individuals with Autism Spectrum Disorder

    PubMed Central

    Venkataraman, Archana; Yang, Daniel Y.-J.; Dvornek, Nicha; Staib, Lawrence H.; Duncan, James S.; Pelphrey, Kevin A.; Ventola, Pamela

    2016-01-01

    Behavioral interventions for autism have gained prominence in recent years; however, the neural-systems-level targets of these interventions remain poorly understood. We use a novel Bayesian framework to extract network-based differences before and after a 16-week Pivotal Response Treatment (PRT) regimen. Our results suggest that functional changes induced by PRT localize to the posterior cingulate and are marked by a shift in connectivity from the orbitofrontal cortex to the occipital temporal cortex. Our results illuminate a potential PRT-induced learning mechanism, whereby the neural circuits involved during social perception shift from sensory and attentional systems to higher-level object and face processing areas. PMID:27532879

  8. Fungal biogeography. Global diversity and geography of soil fungi.

    PubMed

    Tedersoo, Leho; Bahram, Mohammad; Põlme, Sergei; Kõljalg, Urmas; Yorou, Nourou S; Wijesundera, Ravi; Villarreal Ruiz, Luis; Vasco-Palacios, Aída M; Thu, Pham Quang; Suija, Ave; Smith, Matthew E; Sharp, Cathy; Saluveer, Erki; Saitta, Alessandro; Rosas, Miguel; Riit, Taavi; Ratkowsky, David; Pritsch, Karin; Põldmaa, Kadri; Piepenbring, Meike; Phosri, Cherdchai; Peterson, Marko; Parts, Kaarin; Pärtel, Kadri; Otsing, Eveli; Nouhra, Eduardo; Njouonkou, André L; Nilsson, R Henrik; Morgado, Luis N; Mayor, Jordan; May, Tom W; Majuakim, Luiza; Lodge, D Jean; Lee, Su See; Larsson, Karl-Henrik; Kohout, Petr; Hosaka, Kentaro; Hiiesalu, Indrek; Henkel, Terry W; Harend, Helery; Guo, Liang-dong; Greslebin, Alina; Grelet, Gwen; Geml, Jozsef; Gates, Genevieve; Dunstan, William; Dunk, Chris; Drenkhan, Rein; Dearnaley, John; De Kesel, André; Dang, Tan; Chen, Xin; Buegger, Franz; Brearley, Francis Q; Bonito, Gregory; Anslan, Sten; Abell, Sandra; Abarenkov, Kessy

    2014-11-28

    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. Climatic factors, followed by edaphic and spatial variables, constitute the best predictors of fungal richness and community composition at the global scale. Fungi show similar latitudinal diversity gradients to other organisms, with several notable exceptions. These findings advance our understanding of global fungal diversity patterns and permit integration of fungi into a general macroecological framework. Copyright © 2014, American Association for the Advancement of Science.

  9. How to train your microbe: methods for dynamically characterizing gene networks

    PubMed Central

    Castillo-Hair, Sebastian M.; Igoshin, Oleg A.; Tabor, Jeffrey J.

    2015-01-01

    Gene networks regulate biological processes dynamically. However, researchers have largely relied upon static perturbations, such as growth media variations and gene knockouts, to elucidate gene network structure and function. Thus, much of the regulation on the path from DNA to phenotype remains poorly understood. Recent studies have utilized improved genetic tools, hardware, and computational control strategies to generate precise temporal perturbations outside and inside of live cells. These experiments have, in turn, provided new insights into the organizing principles of biology. Here, we introduce the major classes of dynamical perturbations that can be used to study gene networks, and discuss technologies available for creating them in a wide range of microbial pathways. PMID:25677419

  10. Motor and somatosensory conversion disorder: a functional unawareness syndrome?

    PubMed

    Perez, David L; Barsky, Arthur J; Daffner, Kirk; Silbersweig, David A

    2012-01-01

    Although conversion disorder is closely connected to the origins of neurology and psychiatry, it remains poorly understood. In this article, the authors discuss neural and clinical parallels between lesional unawareness disorders and unilateral motor and somatosensory conversion disorder, emphasizing functional neuroimaging/disease correlates. Authors suggest that a functional-unawareness neurobiological framework, mediated by right hemisphere-lateralized, large-scale brain network dysfunction, may play a significant role in the neurobiology of conversion disorder. The perigenual anterior cingulate and the posterior parietal cortices are detailed as important in disease pathophysiology. Further investigations will refine the functional-unawareness concept, clarify the role of affective circuits, and delineate the process through which functional neurologic symptoms emerge.

  11. Successful treatment of dwarfism secondary to long-term steroid therapy in steroid-dependent nephrotic syndrome.

    PubMed

    Sun, Linlin; Chen, Dongping; Zhao, Xuezhi; Xu, Chenggang; Mei, Changlin

    2010-01-01

    Prolonged steroid therapy is generally used for steroid-dependent nephrotic syndrome in pediatric patients. However, dwarfism secondary to a long-term regimen and its successful reverse is rarely reported. The underlying mechanism of dwarfism is still poorly understood, as both long-term steroid use and nephrotic syndrome may interact or independently interfere with the process of growth. Here, we present a 17-year-old patient with dwarfism and steroid-dependent nephrotic syndrome and the successful treatment by recombinant human growth factor and cyclosporine A with withdrawal of steroid. We also briefly review the current understanding and the management of dwarfism in pediatric patients with nephrotic syndrome.

  12. Selective Neuronal Activation by Cochlear Implant Stimulation in Auditory Cortex of Awake Primate

    PubMed Central

    Johnson, Luke A.; Della Santina, Charles C.

    2016-01-01

    Despite the success of cochlear implants (CIs) in human populations, most users perform poorly in noisy environments and music and tonal language perception. How CI devices engage the brain at the single neuron level has remained largely unknown, in particular in the primate brain. By comparing neuronal responses with acoustic and CI stimulation in marmoset monkeys unilaterally implanted with a CI electrode array, we discovered that CI stimulation was surprisingly ineffective at activating many neurons in auditory cortex, particularly in the hemisphere ipsilateral to the CI. Further analyses revealed that the CI-nonresponsive neurons were narrowly tuned to frequency and sound level when probed with acoustic stimuli; such neurons likely play a role in perceptual behaviors requiring fine frequency and level discrimination, tasks that CI users find especially challenging. These findings suggest potential deficits in central auditory processing of CI stimulation and provide important insights into factors responsible for poor CI user performance in a wide range of perceptual tasks. SIGNIFICANCE STATEMENT The cochlear implant (CI) is the most successful neural prosthetic device to date and has restored hearing in hundreds of thousands of deaf individuals worldwide. However, despite its huge successes, CI users still face many perceptual limitations, and the brain mechanisms involved in hearing through CI devices remain poorly understood. By directly comparing single-neuron responses to acoustic and CI stimulation in auditory cortex of awake marmoset monkeys, we discovered that neurons unresponsive to CI stimulation were sharply tuned to frequency and sound level. Our results point out a major deficit in central auditory processing of CI stimulation and provide important insights into mechanisms underlying the poor CI user performance in a wide range of perceptual tasks. PMID:27927962

  13. The impacts of livestock diseases and their control on growth and development processes that are pro-poor

    PubMed Central

    Perry, Brian; Grace, Delia

    2009-01-01

    Poverty is now at the heart of development discourse; we discuss how it is measured and understood. We next consider the negative and positive impacts of livestock on pro-poor development. Taking a value-chain approach that includes keepers, users and eaters of livestock, we identify diseases that are road blocks on the ‘three livestock pathways out of poverty’. We discuss livestock impacts on poverty reduction and review attempts to prioritize the livestock diseases relevant to the poor. We make suggestions for metrics that better measure disease impact and show the benefits of more rigorous evaluation before reviewing recent attempts to measure the importance of disease to the poor. High impact of a disease does not guarantee high benefits from its control; other factors must be taken into consideration, including technical feasibility and political desirability. We conclude by considering how we might better understand and exploit the roles of livestock and improved animal health by posing three speculative questions on the impact of livestock diseases and their control on global poverty: how can understanding livestock and poverty links help disease control?; if global poverty reduction was the aim of livestock disease control, how would it differ from the current model?; and how much of the impact of livestock disease on poverty is due to disease control policy rather than disease itself? PMID:19687035

  14. 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.

  15. Aerosol physicochemical properties in relation to meteorology: Case studies in urban, marine, and arid settings

    NASA Astrophysics Data System (ADS)

    Wonaschuetz, Anna

    Atmospheric aerosols are a highly relevant component of the climate system affecting atmospheric radiative transfer and the hydrological cycle. As opposed to other key atmospheric constituents with climatic relevance, atmospheric aerosol particles are highly heterogeneous in time and space with respect to their size, concentration, chemical composition and physical properties. Many aspects of their life cycle are not understood, making them difficult to represent in climate models and hard to control as a pollutant. Aerosol-cloud interactions in particular are infamous as a major source of uncertainty in future climate predictions. Field measurements are an important source of information for the modeling community and can lead to a better understanding of chemical and microphysical processes. In this study, field data from urban, marine, and arid settings are analyzed and the impact of meteorological conditions on the evolution of aerosol particles while in the atmosphere is investigated. Particular attention is given to organic aerosols, which are a poorly understood component of atmospheric aerosols. Local wind characteristics, solar radiation, relative humidity and the presence or absence of clouds and fog are found to be crucial factors in the transport and chemical evolution of aerosol particles. Organic aerosols in particular are found to be heavily impacted by processes in the liquid phase (cloud droplets and aerosol water). The reported measurements serve to improve the process-level understanding of aerosol evolution in different environments and to inform the modeling community by providing realistic values for input parameters and validation of model calculations.

  16. Decision making by patients with breast cancer: the role of information in treatment selection.

    PubMed

    Hughes, K K

    1993-05-01

    In recent years, patients have become more involved in the clinical decision-making process, yet the nature of this process, including the role of information, is poorly understood. The purpose of this exploratory study was to examine the relationship between information about breast cancer treatment alternatives and patients' choices of treatments. The target population was all patients with breast cancer in the process of deciding between breast conservation (lumpectomy plus irradiation) and more traditional management (modified radical mastectomy, with or without reconstruction). A convenience sample of 71 female patients with stage I or II breast cancer was drawn from a breast clinic affiliated with a 1,000-bed tertiary medical center. The amount of information provided to each subject and the nature of its presentation were recorded using an observer checklist. Recall of information and final treatment selection were ascertained during telephone interviews conducted six to eight weeks after surgery. The results indicate that subjects' choice of treatment was unrelated to the amount of information they received during the clinic visit. Manner of presentation also did not influence treatment selection. However, treatment selection was related to the amount of information subjects received prior to their clinic visit (p < 0.01). The results also indicate that patients' recall of information about treatments and associated risks is exceedingly poor. Clinical and legal implications are discussed and recommendations for further research are offered in this article.

  17. 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.

  18. 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...

  19. 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...

  20. 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.

  1. 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

  2. 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.

  3. Towards an integrated understanding of how micro scale processes shape groundwater ecosystem functions.

    PubMed

    Schmidt, Susanne I; Cuthbert, Mark O; Schwientek, Marc

    2017-08-15

    Micro scale processes are expected to have a fundamental role in shaping groundwater ecosystems and yet they remain poorly understood and under-researched. In part, this is due to the fact that sampling is rarely carried out at the scale at which microorganisms, and their grazers and predators, function and thus we lack essential information. While set within a larger scale framework in terms of geochemical features, supply with energy and nutrients, and exchange intensity and dynamics, the micro scale adds variability, by providing heterogeneous zones at the micro scale which enable a wider range of redox reactions. Here we outline how understanding micro scale processes better may lead to improved appreciation of the range of ecosystems functions taking place at all scales. Such processes are relied upon in bioremediation and we demonstrate that ecosystem modelling as well as engineering measures have to take into account, and use, understanding at the micro scale. We discuss the importance of integrating faunal processes and computational appraisals in research, in order to continue to secure sustainable water resources from groundwater. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Proposal for management and alkalinity transformation of bauxite residue in China.

    PubMed

    Xue, Shengguo; Kong, Xiangfeng; Zhu, Feng; Hartley, William; Li, Xiaofei; Li, Yiwei

    2016-07-01

    Bauxite residue is a hazardous solid waste produced during the production of alumina. Its high alkalinity is a potential threat to the environment which may disrupt the surrounding ecological balance of its disposal areas. China is one of the major global producers of alumina and bauxite residue, but differences in alkalinity and associated chemistry exist between residues from China and those from other countries. A detailed understanding of the chemistry of bauxite residue remains the key to improving its management, both in terms of minimizing environmental impacts and reducing its alkaline properties. The nature of bauxite residue and the chemistry required for its transformation are still poorly understood. This review focuses on various transformation processes generated from the Bayer process, sintering process, and combined Bayer-sintering process in China. Problems associated with transformation mechanisms, technical methods, and relative merits of these technologies are reviewed, while current knowledge gaps and research priorities are recommended. Future research should focus on transformation chemistry and its associated mechanisms and for the development of a clear and economic process to reduce alkalinity and soda in bauxite residue.

  5. Processes of recovery through routine or specialist treatment for borderline personality disorder (BPD): a qualitative study.

    PubMed

    Katsakou, Christina; Pistrang, Nancy; Barnicot, Kirsten; White, Hayley; Priebe, Stefan

    2017-07-04

    Recovery processes in borderline personality disorder (BPD) are poorly understood. This study explored how recovery in BPD occurs through routine or specialist treatment, as perceived by service users (SUs) and therapists. SUs were recruited from two specialist BPD services, three community mental health teams, and one psychological therapies service. Semi-structured interviews were conducted with 48 SUs and 15 therapists. The "framework" approach was used to analyse the data. The findings were organized into two domains of themes. The first domain described three parallel processes that constituted SUs' recovery journey: fighting ambivalence and committing to taking action; moving from shame to self-acceptance and compassion; and moving from distrust and defensiveness to opening up to others. The second domain described four therapeutic challenges that needed to be addressed to support this journey: balancing self-exploration and finding solutions; balancing structure and flexibility; confronting interpersonal difficulties and practicing new ways of relating; and balancing support and independence. Therapies facilitating the identified processes may promote recovery. The recovery processes and therapeutic challenges identified in this study could provide a framework to guide future research.

  6. Pubertal status associations with reward and threat sensitivities and subcortical brain volumes during adolescence.

    PubMed

    Urošević, Snežana; Collins, Paul; Muetzel, Ryan; Lim, Kelvin O; Luciana, Monica

    2014-08-01

    Adolescence is characterized by complex developmental processes that impact behavior, biology, and social functioning. Two such adolescence-specific processes are puberty and increases in reward sensitivity. Relations between these processes are poorly understood. The present study focused on examining unique effects of puberty, age, and sex on reward and threat sensitivities and volumes of subcortical brain structures relevant for reward/threat processing in a healthy sample of 9-18year-olds. Unlike age, pubertal status had a significant unique positive relationship with reward sensitivity. In addition, there was a trend for adolescent females to exhibit higher threat sensitivity with more advanced pubertal development and higher reward and threat sensitivity with older age. Similarly, there were significant puberty by sex interaction effects on striatal volumes, i.e., left nucleus accumbens and right pallidum. The present pattern of results suggests that pubertal development, independent of chronological age, is uniquely associated with reward hypersensitivity and with structural differences in striatal regions implicated in reward processing. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. The Solar Dynamo

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    1998-01-01

    The solar dynamo is the process by which the Sun's magnetic field is generated through the interaction of the field with convection and rotation. In this, it is kin to planetary dynamos and other stellar dynamos. Although the precise mechanism by which the Sun generates its field remains poorly understood despite decades of theoretical and observational work, recent advances suggest that solutions to this solar dynamo problem may be forthcoming. Two basic processes are involved in dynamo activity. When the fluid stresses dominate the magnetic stresses (high plasma beta = 8(pi)rho/B(sup 2)), shear flows can stretch magnetic field lines in the direction of the shear (the "alpha effect") and helical flows can lift and twist field lines into orthogonal planes (the "alpha effect"). These two processes can be active anywhere in the solar convection zone but with different results depending upon their relative strengths and signs. Little is known about how and where these processes occur. Other processes, such as magnetic diffusion and the effects of the fine scale structure of the solar magnetic field, pose additional problems.

  8. Characteristic of root decomposition in a tropical rainforest in Sarawak, Malaysi

    NASA Astrophysics Data System (ADS)

    Ohashi, Mizue; Makita, Naoki; Katayam, Ayumi; Kume, Tomonori; Matsumoto, Kazuho; Khoon Kho, L.

    2016-04-01

    Woody roots play a significant role in forest carbon cycling, as up to 60 percent of tree photosynthetic production can be allocated to belowground. Root decay is one of the main processes of soil C dynamics and potentially relates to soil C sequestration. However, much less attention has been paid for root litter decomposition compared to the studies of leaf litter because roots are hidden from view. Previous studies have revealed that physico-chemical quality of roots, climate, and soil organisms affect root decomposition significantly. However, patterns and mechanisms of root decomposition are still poorly understood because of the high variability of root properties, field environment and potential decomposers. For example, root size would be a factor controlling decomposition rates, but general understanding of the difference between coarse and fine root decompositions is still lacking. Also, it is known that root decomposition is performed by soil animals, fungi and bacteria, but their relative importance is poorly understood. In this study, therefore, we aimed to characterize the root decomposition in a tropical rainforest in Sarawak, Malaysia, and clarify the impact of soil living organisms and root sizes on root litter decomposition. We buried soil cores with fine and coarse root litter bags in soil in Lambir Hills National Park. Three different types of soil cores that are covered by 1.5 cm plastic mesh, root-impermeable sheet (50um) and fungi-impermeable sheet (1um) were prepared. The soil cores were buried in February 2013 and collected 4 times, 134 days, 226 days, 786 days and 1151 days after the installation. We found that nearly 80 percent of the coarse root litter was decomposed after two years, whereas only 60 percent of the fine root litter was decomposed. Our results also showed significantly different ratio of decomposition between different cores, suggesting the different contribution of soil living organisms to decomposition process.

  9. Measurements of evaporation from a mine void lake and testing of modelling approaches

    NASA Astrophysics Data System (ADS)

    McJannet, David; Hawdon, Aaron; Van Niel, Tom; Boadle, Dave; Baker, Brett; Trefry, Mike; Rea, Iain

    2017-12-01

    Pit lakes often form in the void that remains after open cut mining operations cease. As pit lakes fill, hydrological and geochemical processes interact and these need to be understood for appropriate management actions to be implemented. Evaporation is important in the evolution of pit lakes as it acts to concentrate various constituents, controls water level and changes the thermal characteristics of the water body. Despite its importance, evaporation from pit lakes is poorly understood. To address this, we used an automated floating evaporation pan and undertook measurements at a pit lake over a 12 month period. We also developed a new procedure for correcting floating pan evaporation estimates to lake evaporation estimates based on surface temperature differences. Total annual evaporation was 2690 mm and reflected the strong radiation inputs, high temperatures and low humidity experienced in this region. Measurements were used to test the performance of evaporation estimates derived using both pan coefficient and aerodynamic modelling techniques. Daily and monthly evaporation estimates were poorly reproduced using pan coefficient techniques and their use is not recommended for such environments. Aerodynamic modelling was undertaken using a range of input datasets that may be available to those who manage pit lake systems. Excellent model performance was achieved using over-water or local over-land meteorological observations, particularly when the sheltering effects of the pit were considered. Model performance was reduced when off-site data were utilised and differences between local and off-site vapor pressure and wind speed were found to be the major cause.

  10. Posterior cingulate cortex mediates outcome-contingent allocation of behavior

    PubMed Central

    Hayden, Benjamin Y.; Nair, Amrita C.; McCoy, Allison N.; Platt, Michael L.

    2008-01-01

    SUMMARY Adaptive decision making requires selecting an action and then monitoring its consequences to improve future decisions. The neuronal mechanisms supporting action evaluation and subsequent behavioral modification, however, remain poorly understood. To investigate the contribution of posterior cingulate cortex (CGp) to these processes, we recorded activity of single neurons in monkeys performing a gambling task in which the reward outcome of each choice strongly influenced subsequent choices. We found that CGp neurons signaled reward outcomes in a nonlinear fashion, and that outcome-contingent modulations in firing rate persisted into subsequent trials. Moreover, firing rate on any one trial predicted switching to the alternative option on the next trial. Finally, microstimulation in CGp following risky choices promoted a preference reversal for the safe option on the following trial. Collectively, these results demonstrate that CGp directly contributes to the evaluative processes that support dynamic changes in decision making in volatile environments. PMID:18940585

  11. Different forms of effective connectivity in primate frontotemporal pathways.

    PubMed

    Petkov, Christopher I; Kikuchi, Yukiko; Milne, Alice E; Mishkin, Mortimer; Rauschecker, Josef P; Logothetis, Nikos K

    2015-01-23

    It is generally held that non-primary sensory regions of the brain have a strong impact on frontal cortex. However, the effective connectivity of pathways to frontal cortex is poorly understood. Here we microstimulate sites in the superior temporal and ventral frontal cortex of monkeys and use functional magnetic resonance imaging to evaluate the functional activity resulting from the stimulation of interconnected regions. Surprisingly, we find that, although certain earlier stages of auditory cortical processing can strongly activate frontal cortex, downstream auditory regions, such as voice-sensitive cortex, appear to functionally engage primarily an ipsilateral temporal lobe network. Stimulating other sites within this activated temporal lobe network shows strong activation of frontal cortex. The results indicate that the relative stage of sensory processing does not predict the level of functional access to the frontal lobes. Rather, certain brain regions engage local networks, only parts of which have a strong functional impact on frontal cortex.

  12. Early solar system. Stellar origin of the ¹⁸²Hf cosmochronometer and the presolar history of solar system matter.

    PubMed

    Lugaro, Maria; Heger, Alexander; Osrin, Dean; Goriely, Stephane; Zuber, Kai; Karakas, Amanda I; Gibson, Brad K; Doherty, Carolyn L; Lattanzio, John C; Ott, Ulrich

    2014-08-08

    Among the short-lived radioactive nuclei inferred to be present in the early solar system via meteoritic analyses, there are several heavier than iron whose stellar origin has been poorly understood. In particular, the abundances inferred for (182)Hf (half-life = 8.9 million years) and (129)I (half-life = 15.7 million years) are in disagreement with each other if both nuclei are produced by the rapid neutron-capture process. Here, we demonstrate that contrary to previous assumption, the slow neutron-capture process in asymptotic giant branch stars produces (182)Hf. This has allowed us to date the last rapid and slow neutron-capture events that contaminated the solar system material at ~100 million years and ~30 million years, respectively, before the formation of the Sun. Copyright © 2014, American Association for the Advancement of Science.

  13. Metagenomic Analyses Reveal That Energy Transfer Gene Abundances Can Predict the Syntrophic Potential of Environmental Microbial Communities.

    PubMed

    Oberding, Lisa; Gieg, Lisa M

    2016-01-05

    Hydrocarbon compounds can be biodegraded by anaerobic microorganisms to form methane through an energetically interdependent metabolic process known as syntrophy. The microorganisms that perform this process as well as the energy transfer mechanisms involved are difficult to study and thus are still poorly understood, especially on an environmental scale. Here, metagenomic data was analyzed for specific clusters of orthologous groups (COGs) related to key energy transfer genes thus far identified in syntrophic bacteria, and principal component analysis was used in order to determine whether potentially syntrophic environments could be distinguished using these syntroph related COGs as opposed to universally present COGs. We found that COGs related to hydrogenase and formate dehydrogenase genes were able to distinguish known syntrophic consortia and environments with the potential for syntrophy from non-syntrophic environments, indicating that these COGs could be used as a tool to identify syntrophic hydrocarbon biodegrading environments using metagenomic data.

  14. The role of water content in triboelectric charging of wind-blown sand.

    PubMed

    Gu, Zhaolin; Wei, Wei; Su, Junwei; Yu, Chuck Wah

    2013-01-01

    Triboelectric charging is common in desert sandstorms and dust devils on Earth; however, it remains poorly understood. Here we show a charging mechanism of sands with the adsorbed water on micro-porous surface in wind-blown sand based on the fact that water content is universal but usually a minor component in most particle systems. The triboelectric charging could be resulted due to the different mobility of H(+)/OH(-) between the contacting sands with a temperature difference. Computational fluid dynamics (CFD) and discrete element method (DEM) were used to demonstrate the dynamics of the sand charging. The numerically simulated charge-to-mass ratios of sands and electric field strength established in wind tunnel agreed well with the experimental data. The charging mechanism could provide an explanation for the charging process of all identical granular systems with water content, including Martian dust devils, wind-blown snow, even powder electrification in industrial processes.

  15. The neural correlates of reciprocity are sensitive to prior experience of reciprocity.

    PubMed

    Cáceda, Ricardo; Prendes-Alvarez, Stefania; Hsu, Jung-Jiin; Tripathi, Shanti P; Kilts, Clint D; James, G Andrew

    2017-08-14

    Reciprocity is central to human relationships and is strongly influenced by multiple factors including the nature of social exchanges and their attendant emotional reactions. Despite recent advances in the field, the neural processes involved in this modulation of reciprocal behavior by ongoing social interaction are poorly understood. We hypothesized that activity within a discrete set of neural networks including a putative moral cognitive neural network is associated with reciprocity behavior. Nineteen healthy adults underwent functional magnetic resonance imaging scanning while playing the trustee role in the Trust Game. Personality traits and moral development were assessed. Independent component analysis was used to identify task-related functional brain networks and assess their relationship to behavior. The saliency network (insula and anterior cingulate) was positively correlated with reciprocity behavior. A consistent array of brain regions supports the engagement of emotional, self-referential and planning processes during social reciprocity behavior. Published by Elsevier B.V.

  16. Defining the human deubiquitinating enzyme interaction landscape.

    PubMed

    Sowa, Mathew E; Bennett, Eric J; Gygi, Steven P; Harper, J Wade

    2009-07-23

    Deubiquitinating enzymes (Dubs) function to remove covalently attached ubiquitin from proteins, thereby controlling substrate activity and/or abundance. For most Dubs, their functions, targets, and regulation are poorly understood. To systematically investigate Dub function, we initiated a global proteomic analysis of Dubs and their associated protein complexes. This was accomplished through the development of a software platform called CompPASS, which uses unbiased metrics to assign confidence measurements to interactions from parallel nonreciprocal proteomic data sets. We identified 774 candidate interacting proteins associated with 75 Dubs. Using Gene Ontology, interactome topology classification, subcellular localization, and functional studies, we link Dubs to diverse processes, including protein turnover, transcription, RNA processing, DNA damage, and endoplasmic reticulum-associated degradation. This work provides the first glimpse into the Dub interaction landscape, places previously unstudied Dubs within putative biological pathways, and identifies previously unknown interactions and protein complexes involved in this increasingly important arm of the ubiquitin-proteasome pathway.

  17. Defining the Human Deubiquitinating Enzyme Interaction Landscape

    PubMed Central

    Sowa, Mathew E.; Bennett, Eric J.; Gygi, Steven P.; Harper, J. Wade

    2009-01-01

    Summary Deubiquitinating enzymes (Dubs) function to remove covalently attached ubiquitin from proteins, thereby controlling substrate activity and/or abundance. For most Dubs, their functions, targets, and regulation are poorly understood. To systematically investigate Dub function, we initiated a global proteomic analysis of Dubs and their associated protein complexes. This was accomplished through the development of a software platform, called CompPASS, which uses unbiased metrics to assign confidence measurements to interactions from parallel non-reciprocal proteomic datasets. We identified 774 candidate interacting proteins associated with 75 Dubs. Using Gene Ontology, interactome topology classification, sub-cellular localization and functional studies, we link Dubs to diverse processes, including protein turnover, transcription, RNA processing, DNA damage, and endoplasmic reticulum-associated degradation. This work provides the first glimpse into the Dub interaction landscape, places previously unstudied Dubs within putative biological pathways, and identifies previously unknown interactions and protein complexes involved in this increasingly important arm of the ubiquitin-proteasome pathway. PMID:19615732

  18. Anti-resorptive osteonecrosis of the jaws: facts forgotten, questions answered, lessons learned.

    PubMed

    Carlson, Eric R; Schlott, Benjamin J

    2014-05-01

    Osteonecrosis of the jaws associated with bisphosphonate and other anti-resorptive medications (ARONJ) has historically been a poorly understood disease process in terms of its pathophysiology, prevention and treatment since it was originally described in 2003. In association with its original discovery 11 years ago, non-evidence based speculation of these issues have been published in the international literature and are currently being challenged. A critical analysis of cancer patients with ARONJ, for example, reveals that their osteonecrosis is nearly identical to that of cancer patients who are naive to anti-resorptive medications. In addition, osteonecrosis of the jaws is not unique to patients exposed to anti-resorptive medications, but is also seen in patients with osteomyelitis and other pathologic processes of the jaws. This article represents a review of facts forgotten, questions answered, and lessons learned in general regarding osteonecrosis of the jaws. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. DNA replication components as regulators of epigenetic inheritance--lesson from fission yeast centromere.

    PubMed

    He, Haijin; Gonzalez, Marlyn; Zhang, Fan; Li, Fei

    2014-06-01

    Genetic information stored in DNA is accurately copied and transferred to subsequent generations through DNA replication. This process is accomplished through the concerted actions of highly conserved DNA replication components. Epigenetic information stored in the form of histone modifications and DNA methylation, constitutes a second layer of regulatory information important for many cellular processes, such as gene expression regulation, chromatin organization, and genome stability. During DNA replication, epigenetic information must also be faithfully transmitted to subsequent generations. How this monumental task is achieved remains poorly understood. In this review, we will discuss recent advances on the role of DNA replication components in the inheritance of epigenetic marks, with a particular focus on epigenetic regulation in fission yeast. Based on these findings, we propose that specific DNA replication components function as key regulators in the replication of epigenetic information across the genome.

  20. Implementation of near-infrared spectroscopy in a rat model of cardiac arrest and resuscitation

    NASA Astrophysics Data System (ADS)

    Rodriguez, Juan G.; Xiao, Feng; Ferrara, Davon; Ewing, Jennifer; Zhang, Shu; Alexander, Steven; Battarbee, Harold

    2002-07-01

    Transient global cerebral ischemia accompanying cardiac arrest (CA) often leads to permanent brain damage with poor neurological outcome. The precise chain of events underlying the cerebral damage after CA is still not fully understood. Progress in this area may profit from the development of new non-invasive tools that provide real-time information on the vascular and cellular processes preceding the damage. One way to assess these processes is through near-IR spectroscopy, which has demonstrated the ability to quantify changes in blood volume, hemoglobin oxygenation, cytochrome oxidase redox state, and tissue water content. Here we report on the successful implementation of this form of spectroscopy in a rat model of asphyxial CA and resuscitation, under hypothermic and normothermic conditions. Preliminary results are shown that provide a new temporal insight into the cerebral circulation during CA and post-resuscitation.

  1. Submillisecond Dynamics of Mastoparan X Insertion into Lipid Membranes.

    PubMed

    Schuler, Erin E; Nagarajan, Sureshbabu; Dyer, R Brian

    2016-09-01

    The mechanism of protein insertion into a lipid bilayer is poorly understood because the kinetics of this process is difficult to measure. We developed a new approach to study insertion of the antimicrobial peptide Mastoparan X into zwitterionic lipid vesicles, using a laser-induced temperature-jump to initiate insertion on the microsecond time scale and infrared and fluorescence spectroscopies to follow the kinetics. Infrared probes the desolvation of the peptide backbone and yields biphasic kinetics with relaxation lifetimes of 12 and 117 μs, whereas fluorescence probes the intrinsic tryptophan residue located near the N-terminus and yields a single exponential phase with a lifetime of 440 μs. Arrhenius analysis of the temperature-dependent rates yields an activation energy for insertion of 96 kJ/mol. These results demonstrate the complexity of the insertion process and provide mechanistic insight into the interplay between peptides and the lipid bilayer required for peptide transport across cellular membranes.

  2. Transition from direct to inverted charge transport Marcus regions in molecular junctions via molecular orbital gating

    NASA Astrophysics Data System (ADS)

    Yuan, Li; Wang, Lejia; Garrigues, Alvar R.; Jiang, Li; Annadata, Harshini Venkata; Anguera Antonana, Marta; Barco, Enrique; Nijhuis, Christian A.

    2018-04-01

    Solid-state molecular tunnel junctions are often assumed to operate in the Landauer regime, which describes essentially activationless coherent tunnelling processes. In solution, on the other hand, charge transfer is described by Marcus theory, which accounts for thermally activated processes. In practice, however, thermally activated transport phenomena are frequently observed also in solid-state molecular junctions but remain poorly understood. Here, we show experimentally the transition from the Marcus to the inverted Marcus region in a solid-state molecular tunnel junction by means of intra-molecular orbital gating that can be tuned via the chemical structure of the molecule and applied bias. In the inverted Marcus region, charge transport is incoherent, yet virtually independent of temperature. Our experimental results fit well to a theoretical model that combines Landauer and Marcus theories and may have implications for the interpretation of temperature-dependent charge transport measurements in molecular junctions.

  3. Modulation of the brain's functional network architecture in the transition from wake to sleep

    PubMed Central

    Larson-Prior, Linda J.; Power, Jonathan D.; Vincent, Justin L.; Nolan, Tracy S.; Coalson, Rebecca S.; Zempel, John; Snyder, Abraham Z.; Schlaggar, Bradley L.; Raichle, Marcus E.; Petersen, Steven E.

    2013-01-01

    The transition from quiet wakeful rest to sleep represents a period over which attention to the external environment fades. Neuroimaging methodologies have provided much information on the shift in neural activity patterns in sleep, but the dynamic restructuring of human brain networks in the transitional period from wake to sleep remains poorly understood. Analysis of electrophysiological measures and functional network connectivity of these early transitional states shows subtle shifts in network architecture that are consistent with reduced external attentiveness and increased internal and self-referential processing. Further, descent to sleep is accompanied by the loss of connectivity in anterior and posterior portions of the default-mode network and more locally organized global network architecture. These data clarify the complex and dynamic nature of the transitional period between wake and sleep and suggest the need for more studies investigating the dynamics of these processes. PMID:21854969

  4. Impact of an extreme climatic event on community assembly.

    PubMed

    Thibault, Katherine M; Brown, James H

    2008-03-04

    Extreme climatic events are predicted to increase in frequency and magnitude, but their ecological impacts are poorly understood. Such events are large, infrequent, stochastic perturbations that can change the outcome of entrained ecological processes. Here we show how an extreme flood event affected a desert rodent community that has been monitored for 30 years. The flood (i) caused catastrophic, species-specific mortality; (ii) eliminated the incumbency advantage of previously dominant species; (iii) reset long-term population and community trends; (iv) interacted with competitive and metapopulation dynamics; and (v) resulted in rapid, wholesale reorganization of the community. This and a previous extreme rainfall event were punctuational perturbations-they caused large, rapid population- and community-level changes that were superimposed on a background of more gradual trends driven by climate and vegetation change. Captured by chance through long-term monitoring, the impacts of such large, infrequent events provide unique insights into the processes that structure ecological communities.

  5. Predictive codes of familiarity and context during the perceptual learning of facial identities

    NASA Astrophysics Data System (ADS)

    Apps, Matthew A. J.; Tsakiris, Manos

    2013-11-01

    Face recognition is a key component of successful social behaviour. However, the computational processes that underpin perceptual learning and recognition as faces transition from unfamiliar to familiar are poorly understood. In predictive coding, learning occurs through prediction errors that update stimulus familiarity, but recognition is a function of both stimulus and contextual familiarity. Here we show that behavioural responses on a two-option face recognition task can be predicted by the level of contextual and facial familiarity in a computational model derived from predictive-coding principles. Using fMRI, we show that activity in the superior temporal sulcus varies with the contextual familiarity in the model, whereas activity in the fusiform face area covaries with the prediction error parameter that updated facial familiarity. Our results characterize the key computations underpinning the perceptual learning of faces, highlighting that the functional properties of face-processing areas conform to the principles of predictive coding.

  6. Interdependence of specialization and biodiversity in Phanerozoic marine invertebrates.

    PubMed

    Nürnberg, Sabine; Aberhan, Martin

    2015-03-17

    Studies of the dynamics of biodiversity often suggest that diversity has upper limits, but the complex interplay between ecological and evolutionary processes and the relative role of biotic and abiotic factors that set upper limits to diversity are poorly understood. Here we statistically assess the relationship between global biodiversity and the degree of habitat specialization of benthic marine invertebrates over the Phanerozoic eon. We show that variation in habitat specialization correlates positively with changes in global diversity, that is, times of high diversity coincide with more specialized faunas. We identify the diversity dynamics of specialists but not generalists, and origination rates but not extinction rates, as the main drivers of this ecological interdependence. Abiotic factors fail to show any significant relationship with specialization. Our findings suggest that the overall level of specialization and its fluctuations over evolutionary timescales are controlled by diversity-dependent processes--driven by interactions between organisms competing for finite resources.

  7. Different forms of effective connectivity in primate frontotemporal pathways

    PubMed Central

    Petkov, Christopher I.; Kikuchi, Yukiko; Milne, Alice E.; Mishkin, Mortimer; Rauschecker, Josef P.; Logothetis, Nikos K.

    2015-01-01

    It is generally held that non-primary sensory regions of the brain have a strong impact on frontal cortex. However, the effective connectivity of pathways to frontal cortex is poorly understood. Here we microstimulate sites in the superior temporal and ventral frontal cortex of monkeys and use functional magnetic resonance imaging to evaluate the functional activity resulting from the stimulation of interconnected regions. Surprisingly, we find that, although certain earlier stages of auditory cortical processing can strongly activate frontal cortex, downstream auditory regions, such as voice-sensitive cortex, appear to functionally engage primarily an ipsilateral temporal lobe network. Stimulating other sites within this activated temporal lobe network shows strong activation of frontal cortex. The results indicate that the relative stage of sensory processing does not predict the level of functional access to the frontal lobes. Rather, certain brain regions engage local networks, only parts of which have a strong functional impact on frontal cortex. PMID:25613079

  8. The Development of a Program Engagement Theory for Group Offending Behavior Programs.

    PubMed

    Holdsworth, Emma; Bowen, Erica; Brown, Sarah; Howat, Douglas

    2017-10-01

    Offender engagement in group offending behavior programs is poorly understood and under-theorized. In addition, there is no research on facilitators' engagement. This article presents the first ever theory to address this gap. A Program Engagement Theory (PET) was derived from a constructivist grounded theory analysis that accounts for both facilitators' and offenders' engagement in group offending behavior programs (GOBPs). Interviews and session observations were used to collect data from 23 program facilitators and 28 offenders (group members). The analysis revealed that group members' engagement involved shared identities and moving on as a group. In turn, this was dependent on facilitators personalising treatment frameworks and establishing a hook to help group members move on. The PET emphasizes the importance of considering change during treatment as a process rather than simply a program outcome. Solution-focused (SF) programs were more conducive to engagement and the change process than offence-focused programs.

  9. Meta-Analysis of the Core Aroma Components of Grape and Wine Aroma

    PubMed Central

    Ilc, Tina; Werck-Reichhart, Danièle; Navrot, Nicolas

    2016-01-01

    Wine aroma strongly influences wine quality, yet its composition and its evolution during the winemaking process are poorly understood. Volatile compounds that constitute wine aroma are traditionally divided into three classes according to their origin: grape, fermentation, and maturation aroma. We challenge this view with meta-analysis and review of grape and wine volatiles and their precursors from 82 profiling experiments. We compiled a list of 141 common grape and wine volatiles and quantitatively compared 43 of them. Our work offers insight into complex relationships between biosynthesis of aroma in grapes and the changes during the winemaking process. Monoterpenes are one of the largest and most researched wine aroma compounds. We show that their diversity in wines is mainly due to the oxidative metabolism of linalool in grapes. Furthermore, we demonstrate that most of the linalool produced in grapes is converted to these oxidized derivatives. PMID:27746799

  10. Reducing Diagnostic Errors through Effective Communication: Harnessing the Power of Information Technology

    PubMed Central

    Naik, Aanand Dinkar; Rao, Raghuram; Petersen, Laura Ann

    2008-01-01

    Diagnostic errors are poorly understood despite being a frequent cause of medical errors. Recent efforts have aimed to advance the "basic science" of diagnostic error prevention by tracing errors to their most basic origins. Although a refined theory of diagnostic error prevention will take years to formulate, we focus on communication breakdown, a major contributor to diagnostic errors and an increasingly recognized preventable factor in medical mishaps. We describe a comprehensive framework that integrates the potential sources of communication breakdowns within the diagnostic process and identifies vulnerable steps in the diagnostic process where various types of communication breakdowns can precipitate error. We then discuss potential information technology-based interventions that may have efficacy in preventing one or more forms of these breakdowns. These possible intervention strategies include using new technologies to enhance communication between health providers and health systems, improve patient involvement, and facilitate management of information in the medical record. PMID:18373151

  11. 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.

  12. Sleep facilitates consolidation of emotional declarative memory.

    PubMed

    Hu, Peter; Stylos-Allan, Melinda; Walker, Matthew P

    2006-10-01

    Both sleep and emotion are known to modulate processes of memory consolidation, yet their interaction is poorly understood. We examined the influence of sleep on consolidation of emotionally arousing and neutral declarative memory. Subjects completed an initial study session involving arousing and neutral pictures, either in the evening or in the morning. Twelve hours later, after sleeping or staying awake, subjects performed a recognition test requiring them to discriminate between these original pictures and novel pictures by responding "remember,"know" (familiar), or "new." Selective sleep effects were observed for consolidation of emotional memory: Recognition accuracy for know judgments of arousing stimuli improved by 42% after sleep relative to wake, and recognition bias for remember judgments of these stimuli increased by 58% after sleep relative to wake (resulting in more conservative responding). These findings hold important implications for understanding of human memory processing, suggesting that the facilitation of memory for emotionally salient information may preferentially develop during sleep.

  13. Diversity in arrestin function.

    PubMed

    Kendall, Ryan T; Luttrell, Louis M

    2009-09-01

    The termination of heptahelical receptor signaling is a multilevel process coordinated, in large part, by members of the arrestin family of proteins. Arrestin binding to agonist-occupied receptors promotes desensitization by interrupting receptor-G protein coupling, while simultaneously recruiting machinery for receptor endocytosis, vesicular trafficking, and receptor fate determination. By simultaneously binding other proteins, arrestins also act as ligand-regulated scaffolds that recruit protein and lipid kinase, phosphatase, phosphodiesterase, and ubiquitin ligase activity into receptor-based multiprotein 'signalsome' complexes. Arrestin-binding thus 'switches' receptors from a transient G protein-coupled state to a persistent arrestin-coupled state that continues to signal as the receptor transits intracellular compartments. While it is clear that signalsome assembly has profound effects on the duration and spatial characteristics of heptahelical receptor signals, the physiologic functions of this novel signaling mechanism are poorly understood. Growing evidence suggests that signalsomes regulate such diverse processes as endocytosis and exocytosis, cell migration, survival, and contractility.

  14. Compaction behavior of out-of-autoclave prepreg materials

    NASA Astrophysics Data System (ADS)

    Serrano, Léonard; Olivier, Philippe; Cinquin, Jacques

    2017-10-01

    The main challenges with composite parts manufacturing are related to the curing means, mainly autoclaves, the length of their cycles and their operating costs. In order to decrease this dependency, out of autoclave materials have been considered as a solution for high production rate parts such as spars, flaps, etc… However, most out-of-autoclave process do not possess the same maturity as their counterpart, especially concerning part quality1. Some pre-cure processes such as compaction and ply lay-up are usually less of a concern for autoclave manufacturing: the pressure applied during the cycle participates to reduce the potential defects (porosity caused by a poor quality lay-up, bad compaction, entrapped air or humidity…). For out-of-autoclave parts, those are crucial steps which may have many consequences on the final quality of the laminate2. In order to avoid this quality loss, those steps must be well understood.

  15. Impact of a Regional Drought on Terrestrial Carbon Fluxes and Atmospheric Carbon: Results from a Coupled Carbon Cycle Model

    NASA Technical Reports Server (NTRS)

    Lee, Eunjee; Koster, Randal D.; Ott, Lesley E.; Weir, Brad; Mahanama, Sarith; Chang, Yehui; Zeng, Fan-Wei

    2017-01-01

    Understanding the underlying processes that control the carbon cycle is key to predicting future global change. Much of the uncertainty in the magnitude and variability of the atmospheric carbon dioxide (CO2) stems from uncertainty in terrestrial carbon fluxes, and the relative impacts of temperature and moisture variations on regional and global scales are poorly understood. Here we investigate the impact of a regional drought on terrestrial carbon fluxes and CO2 mixing ratios over North America using the NASA Goddard Earth Observing System (GEOS) Model. Results show a sequence of changes in carbon fluxes and atmospheric CO2, induced by the drought. The relative contributions of meteorological changes to the neighboring carbon dynamics are also presented. The coupled modeling approach allows a direct quantification of the impact of the regional drought on local and proximate carbon exchange at the land surface via the carbon-water feedback processes.

  16. Origin of microbial biomineralization and magnetotaxis during the Archean.

    PubMed

    Lin, Wei; Paterson, Greig A; Zhu, Qiyun; Wang, Yinzhao; Kopylova, Evguenia; Li, Ying; Knight, Rob; Bazylinski, Dennis A; Zhu, Rixiang; Kirschvink, Joseph L; Pan, Yongxin

    2017-02-28

    Microbes that synthesize minerals, a process known as microbial biomineralization, contributed substantially to the evolution of current planetary environments through numerous important geochemical processes. Despite its geological significance, the origin and evolution of microbial biomineralization remain poorly understood. Through combined metagenomic and phylogenetic analyses of deep-branching magnetotactic bacteria from the Nitrospirae phylum, and using a Bayesian molecular clock-dating method, we show here that the gene cluster responsible for biomineralization of magnetosomes, and the arrangement of magnetosome chain(s) within cells, both originated before or near the Archean divergence between the Nitrospirae and Proteobacteria This phylogenetic divergence occurred well before the Great Oxygenation Event. Magnetotaxis likely evolved due to environmental pressures conferring an evolutionary advantage to navigation via the geomagnetic field. Earth's dynamo must therefore have been sufficiently strong to sustain microbial magnetotaxis in the Archean, suggesting that magnetotaxis coevolved with the geodynamo over geological time.

  17. Influence of the electron-cation interaction on electron mobility in dye-sensitized ZnO and TiO2 nanocrystals: a study using ultrafast terahertz spectroscopy.

    PubMed

    Nemec, H; Rochford, J; Taratula, O; Galoppini, E; Kuzel, P; Polívka, T; Yartsev, A; Sundström, V

    2010-05-14

    Charge transport and recombination in nanostructured semiconductors are poorly understood key processes in dye-sensitized solar cells. We have employed time-resolved spectroscopies in the terahertz and visible spectral regions supplemented with Monte Carlo simulations to obtain unique information on these processes. Our results show that charge transport in the active solar cell material can be very different from that in nonsensitized semiconductors, due to strong electrostatic interaction between injected electrons and dye cations at the surface of the semiconductor nanoparticle. For ZnO, this leads to formation of an electron-cation complex which causes fast charge recombination and dramatically decreases the electron mobility even after the dissociation of the complex. Sensitized TiO2 does not suffer from this problem due to its high permittivity efficiently screening the charges.

  18. Epigenetics of sleep and chronobiology.

    PubMed

    Qureshi, Irfan A; Mehler, Mark F

    2014-03-01

    The circadian clock choreographs fundamental biological rhythms. This system is comprised of the master circadian pacemaker in the suprachiasmatic nucleus and associated pacemakers in other tissues that coordinate complex physiological processes and behaviors, such as sleep, feeding, and metabolism. The molecular circuitry that underlies these clocks and orchestrates circadian gene expression has been the focus of intensive investigation, and it is becoming clear that epigenetic factors are highly integrated into these networks. In this review, we draw attention to the fundamental roles played by epigenetic mechanisms in transcriptional and post-transcriptional regulation within the circadian clock system. We also highlight how alterations in epigenetic factors and mechanisms are being linked with sleep-wake disorders. These observations provide important insights into the pathogenesis and potential treatment of these disorders and implicate epigenetic deregulation in the significant but poorly understood interconnections now emerging between circadian processes and neurodegeneration, metabolic diseases, cancer, and aging.

  19. The role of water content in triboelectric charging of wind-blown sand

    PubMed Central

    Gu, Zhaolin; Wei, Wei; Su, Junwei; Yu, Chuck Wah

    2013-01-01

    Triboelectric charging is common in desert sandstorms and dust devils on Earth; however, it remains poorly understood. Here we show a charging mechanism of sands with the adsorbed water on micro-porous surface in wind-blown sand based on the fact that water content is universal but usually a minor component in most particle systems. The triboelectric charging could be resulted due to the different mobility of H+/OH− between the contacting sands with a temperature difference. Computational fluid dynamics (CFD) and discrete element method (DEM) were used to demonstrate the dynamics of the sand charging. The numerically simulated charge-to-mass ratios of sands and electric field strength established in wind tunnel agreed well with the experimental data. The charging mechanism could provide an explanation for the charging process of all identical granular systems with water content, including Martian dust devils, wind-blown snow, even powder electrification in industrial processes. PMID:23434920

  20. Effect of treatment in a constructed wetland on toxicity of textile wastewater

    USGS Publications Warehouse

    Baughman, G.L.; Perkins, W.S.; Lasier, P.J.; Winger, P.V.

    2003-01-01

    Constructed wetlands for treating wastewater have proliferated in recent years and their characteristics have been studied extensively. In most cases, constructed wetlands have been used primarily for removal of nutrients and heavy metals. Extensive literature is available concerning construction and use of wetlands for treatment of wastewater. Even so, quantitative descriptions of wetland function and processes are highly empirical and difficult to extrapolate. The processes involved in removal of pollutants by wetlands are poorly understood, especially for waste streams as complex as textile effluents. The few studies conducted on treatment of textile wastewater in constructed wetlands were cited in earlier publications. Results of a two-year study of a full-scale wetland treating textile effluent are presented here. The paper describes the effects of the wetland on aquatic toxicity of the wastewater and draws conclusions about the utility and limitations of constructed wetlands for treatment of textile effluents.

  1. Investigation on the infection mechanism of the fungus Clonostachys rosea against nematodes using the green fluorescent protein.

    PubMed

    Zhang, Lin; Yang, Jinkui; Niu, Qiuhong; Zhao, Xuna; Ye, Fengping; Liang, Lianming; Zhang, Ke-Qin

    2008-04-01

    The fungus Clonostachys rosea (syn. Gliocladium roseum) is a potential biocontrol agent. It can suppress the sporulation of the plant pathogenic fungus Botrytis cinerea and kill pathogenic nematodes, but the process of nematode pathogenesis is poorly understood. To help understand the underlying mechanism, we constructed recombinant strains containing a plasmid with both the enhanced green fluorescent protein gene egfp and the hygromycin resistance gene hph. Expression of the green fluorescent protein (GFP) was monitored using fluorescence microscopy. Our observations reveal that the pathogenesis started from the adherence of conidia to nematode cuticle for germination, followed by the penetration of germ tubes into the nematode body and subsequent death and degradation of the nematodes. These are the first findings on the infection process of the fungal pathogen marked with GFP, and the developed method can become an important tool for studying the molecular mechanisms of nematode infection by C. rosea.

  2. Measuring collective transport by defined numbers of processive and nonprocessive kinesin motors.

    PubMed

    Furuta, Ken'ya; Furuta, Akane; Toyoshima, Yoko Y; Amino, Misako; Oiwa, Kazuhiro; Kojima, Hiroaki

    2013-01-08

    Intracellular transport is thought to be achieved by teams of motor proteins bound to a cargo. However, the coordination within a team remains poorly understood as a result of the experimental difficulty in controlling the number and composition of motors. Here, we developed an experimental system that links together defined numbers of motors with defined spacing on a DNA scaffold. By using this system, we linked multiple molecules of two different types of kinesin motors, processive kinesin-1 or nonprocessive Ncd (kinesin-14), in vitro. Both types of kinesins markedly increased their processivities with motor number. Remarkably, despite the poor processivity of individual Ncd motors, the coupling of two Ncd motors enables processive movement for more than 1 μm along microtubules (MTs). This improvement was further enhanced with decreasing spacing between motors. Force measurements revealed that the force generated by groups of Ncd is additive when two to four Ncd motors work together, which is much larger than that generated by single motors. By contrast, the force of multiple kinesin-1s depends only weakly on motor number. Numerical simulations and single-molecule unbinding measurements suggest that this additive nature of the force exerted by Ncd relies on fast MT binding kinetics and the large drag force of individual Ncd motors. These features would enable small groups of Ncd motors to crosslink MTs while rapidly modulating their force by forming clusters. Thus, our experimental system may provide a platform to study the collective behavior of motor proteins from the bottom up.

  3. Belief inhibition during thinking: not always winning but at least taking part.

    PubMed

    De Neys, Wim; Franssens, Samuel

    2009-10-01

    Human thinking is often biased by intuitive beliefs. Inhibition of these tempting beliefs is considered a key component of human thinking, but the process is poorly understood. In the present study we clarify the nature of an inhibition failure and the resulting belief bias by probing the accessibility of cued beliefs after people reasoned. Results indicated that even the poorest reasoners showed an impaired memory access to words that were associated with cued beliefs after solving reasoning problems in which the beliefs conflicted with normative considerations (Experiment 1 and 2). The study further established that the impairment was only temporary in nature (Experiment 3) and did not occur when people were explicitly instructed to give mere intuitive judgments (Experiment 4). Findings present solid evidence for the postulation of an inhibition process and imply that belief bias does not result from a failure to recognize the need to inhibit inappropriate beliefs, but from a failure to complete the inhibition process. This indicates that people are far more logical than hitherto believed.

  4. Bacterial spore inactivation induced by cold plasma.

    PubMed

    Liao, Xinyu; Muhammad, Aliyu Idris; Chen, Shiguo; Hu, Yaqin; Ye, Xingqian; Liu, Donghong; Ding, Tian

    2018-04-05

    Cold plasma has emerged as a non-thermal technology for microbial inactivation in the food industry over the last decade. Spore-forming microorganisms pose challenges for microbiological safety and for the prevention of food spoilage. Inactivation of spores induced by cold plasma has been reported by several studies. However, the exact mechanism of spore deactivation by cold plasma is poorly understood; therefore, it is difficult to control this process and to optimize cold plasma processing for efficient spore inactivation. In this review, we summarize the factors that affect the resistance of spores to cold plasma, including processing parameters, environmental elements, and spore properties. We then describe possible inactivation targets in spore cells (e.g., outer structure, DNA, and metabolic proteins) that associated with inactivation by cold plasma according to previous studies. Kinetic models of the sporicidal activity of cold plasma have also been described here. A better understanding of the interaction between spores and cold plasma is essential for the development and optimization of cold plasma technology in food the industry.

  5. Effect of cathodic polarization on coating doxycycline on titanium surfaces.

    PubMed

    Geißler, Sebastian; Tiainen, Hanna; Haugen, Håvard J

    2016-06-01

    Cathodic polarization has been reported to enhance the ability of titanium based implant materials to interact with biomolecules by forming titanium hydride at the outermost surface layer. Although this hydride layer has recently been suggested to allow the immobilization of the broad spectrum antibiotic doxycycline on titanium surfaces, the involvement of hydride in binding the biomolecule onto titanium remains poorly understood. To gain better understanding of the influence this immobilization process has on titanium surfaces, mirror-polished commercially pure titanium surfaces were cathodically polarized in the presence of doxycycline and the modified surfaces were thoroughly characterized using atomic force microscopy, electron microscopy, secondary ion mass spectrometry, and angle-resolved X-ray spectroscopy. We demonstrated that no hydride was created during the polarization process. Doxycycline was found to be attached to an oxide layer that was modified during the electrochemical process. A bacterial assay using bioluminescent Staphylococcus epidermidis Xen43 showed the ability of the coating to reduce bacterial colonization and planktonic bacterial growth. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. 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.

  7. Bridging the Gaps: the Promise of Omics Studies in Pediatric Exercise Research

    PubMed Central

    Radom-Aizik, Shlomit; Cooper, Dan M.

    2018-01-01

    In this review, we highlight promising new discoveries that may generate useful and clinically relevant insights into the mechanisms that link exercise with growth during critical periods of development. Growth in childhood and adolescence is unique among mammals, and is a dynamic process regulated by an evolution of hormonal and inflammatory mediators, age-dependent progression of gene expression, and environmentally modulated epigenetic mechanisms. Many of these same processes likely affect molecular transducers of physical activity. How the molecular signaling associated with growth is synchronized with signaling associated with exercise is poorly understood. Recent advances in “omics,” namely, genomics and epigenetics, metabolomics, and proteomics, now provide exciting approaches and tools that can be used for the first time to address this gap. A biologic definition of “healthy” exercise that links the metabolic transducers of physical activity with parallel processes that regulate growth will transform health policy and guidelines that promote optimal use of physical activity. PMID:27137166

  8. Emerging Roles for the Lysosome in Lipid Metabolism.

    PubMed

    Thelen, Ashley M; Zoncu, Roberto

    2017-11-01

    Precise regulation of lipid biosynthesis, transport, and storage is key to the homeostasis of cells and organisms. Cells rely on a sophisticated but poorly understood network of vesicular and nonvesicular transport mechanisms to ensure efficient delivery of lipids to target organelles. The lysosome stands at the crossroads of this network due to its ability to process and sort exogenous and endogenous lipids. The lipid-sorting function of the lysosome is intimately connected to its recently discovered role as a metabolic command-and-control center, which relays multiple nutrient cues to the master growth regulator, mechanistic target of rapamycin complex (mTORC)1 kinase. In turn, mTORC1 potently drives anabolic processes, including de novo lipid synthesis, while inhibiting lipid catabolism. Here, we describe the dual role of the lysosome in lipid transport and biogenesis, and we discuss how integration of these two processes may play important roles both in normal physiology and in disease. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Stochastic Community Assembly: Does It Matter in Microbial Ecology?

    PubMed

    Zhou, Jizhong; Ning, Daliang

    2017-12-01

    Understanding the mechanisms controlling community diversity, functions, succession, and biogeography is a central, but poorly understood, topic in ecology, particularly in microbial ecology. Although stochastic processes are believed to play nonnegligible roles in shaping community structure, their importance relative to deterministic processes is hotly debated. The importance of ecological stochasticity in shaping microbial community structure is far less appreciated. Some of the main reasons for such heavy debates are the difficulty in defining stochasticity and the diverse methods used for delineating stochasticity. Here, we provide a critical review and synthesis of data from the most recent studies on stochastic community assembly in microbial ecology. We then describe both stochastic and deterministic components embedded in various ecological processes, including selection, dispersal, diversification, and drift. We also describe different approaches for inferring stochasticity from observational diversity patterns and highlight experimental approaches for delineating ecological stochasticity in microbial communities. In addition, we highlight research challenges, gaps, and future directions for microbial community assembly research. Copyright © 2017 American Society for Microbiology.

  10. Helicobacter pylori shows asymmetric and polar cell divisome assembly associated with DNA replisome.

    PubMed

    Kamran, Mohammad; Dubey, Priyanka; Verma, Vijay; Dasgupta, Santanu; Dhar, Suman K

    2018-05-09

    DNA replication and cell division are two fundamental processes in the life cycle of a cell. The majority of prokaryotic cells undergo division by means of binary fission in coordination with replication of the genome. Both processes, but especially their coordination, are poorly understood in Helicobacter pylori. Here, we studied the cell divisome assembly and the subsequent processes of membrane and peptidoglycan synthesis in the bacterium. To our surprise, we found the cell divisome assembly to be polar, which was well-corroborated by the asymmetric membrane and peptidoglycan synthesis at the poles. The divisome components showed its assembly to be synchronous with that of the replisome and the two remained associated throughout the cell cycle, demonstrating a tight coordination among chromosome replication, segregation and cell division in H. pylori. To our knowledge, this is the first report where both DNA replication and cell division along with their possible association have been demonstrated for this pathogenic bacterium. © 2018 Federation of European Biochemical Societies.

  11. Spatial and temporal variability of rainfall and their effects on hydrological response in urban areas - a review

    NASA Astrophysics Data System (ADS)

    Cristiano, Elena; ten Veldhuis, Marie-claire; van de Giesen, Nick

    2017-07-01

    In urban areas, hydrological processes are characterized by high variability in space and time, making them sensitive to small-scale temporal and spatial rainfall variability. In the last decades new instruments, techniques, and methods have been developed to capture rainfall and hydrological processes at high resolution. Weather radars have been introduced to estimate high spatial and temporal rainfall variability. At the same time, new models have been proposed to reproduce hydrological response, based on small-scale representation of urban catchment spatial variability. Despite these efforts, interactions between rainfall variability, catchment heterogeneity, and hydrological response remain poorly understood. This paper presents a review of our current understanding of hydrological processes in urban environments as reported in the literature, focusing on their spatial and temporal variability aspects. We review recent findings on the effects of rainfall variability on hydrological response and identify gaps where knowledge needs to be further developed to improve our understanding of and capability to predict urban hydrological response.

  12. mRNA export in the apicomplexan parasite Toxoplasma gondii: emerging divergent components of a crucial pathway.

    PubMed

    Ávila, Andréa Rodrigues; Cabezas-Cruz, Alexjandro; Gissot, Mathieu

    2018-01-25

    Control of gene expression is crucial for parasite survival and is the result of a series of processes that are regulated to permit fine-tuning of gene expression in response to biological changes during the life-cycle of apicomplexan parasites. Control of mRNA nuclear export is a key process in eukaryotic cells but is poorly understood in apicomplexan parasites. Here, we review recent knowledge regarding this process with an emphasis on T. gondii. We describe the presence of divergent orthologs and discuss structural and functional differences in export factors between apicomplexans and other eukaryotic lineages. Undoubtedly, the use of the CRISPR/Cas9 system in high throughput screenings associated with the discovery of mRNA nuclear export complexes by proteomic analysis will contribute to identify these divergent factors. Ligand-based or structure-based strategies may be applied to investigate the potential use of these proteins as targets for new antiprotozoal agents.

  13. X-ray emission processes in stars and their immediate environment

    PubMed Central

    Testa, Paola

    2010-01-01

    A decade of X-ray stellar observations with Chandra and XMM-Newton has led to significant advances in our understanding of the physical processes at work in hot (magnetized) plasmas in stars and their immediate environment, providing new perspectives and challenges, and in turn the need for improved models. The wealth of high-quality stellar spectra has allowed us to investigate, in detail, the characteristics of the X-ray emission across the Hertzsprung-Russell (HR) diagram. Progress has been made in addressing issues ranging from classical stellar activity in stars with solar-like dynamos (such as flares, activity cycles, spatial and thermal structuring of the X-ray emitting plasma, and evolution of X-ray activity with age), to X-ray generating processes (e.g., accretion, jets, magnetically confined winds) that were poorly understood in the preChandra/XMM-Newton era. I will discuss the progress made in the study of high energy stellar physics and its impact in a wider astrophysical context, focusing on the role of spectral diagnostics now accessible. PMID:20360562

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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.

  19. 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 ...

  20. 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...

  1. 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…

  2. 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.

  3. Effects of primitive photosynthesis on Earth's early climate system

    NASA Astrophysics Data System (ADS)

    Ozaki, Kazumi; Tajika, Eiichi; Hong, Peng K.; Nakagawa, Yusuke; Reinhard, Christopher T.

    2018-01-01

    The evolution of different forms of photosynthetic life has profoundly altered the activity level of the biosphere, radically reshaping the composition of Earth's oceans and atmosphere over time. However, the mechanistic impacts of a primitive photosynthetic biosphere on Earth's early atmospheric chemistry and climate are poorly understood. Here, we use a global redox balance model to explore the biogeochemical and climatological effects of different forms of primitive photosynthesis. We find that a hybrid ecosystem of H2-based and Fe2+-based anoxygenic photoautotrophs—organisms that perform photosynthesis without producing oxygen—gives rise to a strong nonlinear amplification of Earth's methane (CH4) cycle, and would thus have represented a critical component of Earth's early climate system before the advent of oxygenic photosynthesis. Using a Monte Carlo approach, we find that a hybrid photosynthetic biosphere widens the range of geochemical conditions that allow for warm climate states well beyond either of these metabolic processes acting in isolation. Our results imply that the Earth's early climate was governed by a novel and poorly explored set of regulatory feedbacks linking the anoxic biosphere and the coupled H, C and Fe cycles. We suggest that similar processes should be considered when assessing the potential for sustained habitability on Earth-like planets with reducing atmospheres.

  4. Crystal structure control of aluminized clay minerals on the mobility of caesium in contaminated soil environments

    NASA Astrophysics Data System (ADS)

    Dzene, Liva; Ferrage, Eric; Viennet, Jean-Christophe; Tertre, Emmanuel; Hubert, Fabien

    2017-02-01

    Radioactive caesium pollution resulting from Fukushima Dai-ichi and Chernobyl nuclear plant accidents involves strong interactions between Cs+ and clays, especially vermiculite-type minerals. In acidic soil environments, such as in Fukushima area, vermiculite is subjected to weathering processes, resulting in aluminization. The crystal structure of aluminized clays and its implications for Cs+ mobility in soils remain poorly understood due to the mixture of these minerals with other clays and organic matter. We performed acidic weathering of a vermiculite to mimic the aluminization process in soils. Combination of structure analysis and Cs+ extractability measurements show that the increase of aluminization is accompanied by an increase in Cs+ mobility. Crystal structure model for aluminized vermiculite is based on the interstratification of unaltered vermiculite layers and aluminized layers within the same particle. Cs+ in vermiculite layers is poorly mobile, while the extractability of Cs+ is greatly enhanced in aluminized layers. The overall reactivity of the weathered clay (cation exchange capacity, Cs+ mobility) is then governed by the relative abundance of the two types of layers. The proposed layer model for aluminized vermiculite with two coexisting populations of caesium is of prime importance for predicting the fate of caesium in contaminated soil environments.

  5. 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).

  6. Bioavailability and Effects of Manufactured TiO2 and Quantum Dot Nanomaterials to Environmental Microorganisms (Invited)

    NASA Astrophysics Data System (ADS)

    Holden, P. A.; Nadeau, J. L.; Stucky, G.; Priester, J.; Horst, A.; Vukanti, R.; Ge, Y.; Schimel, J.

    2010-12-01

    Whether through manufacturing processes, waste disposal or the use of consumer goods, manufactured nanomaterials enter soil, sediment and aquatic environments where their impacts are poorly understood. Ecosystem level scale impacts, for example on nutrient cycling and other pollutant biodegradation, are plausible if nanomaterials are bioavailable to, and negatively affect, microbes. Microbes may also contribute to trophic transfer and thus effects to higher organisms. We present data from studies of CdSe quantum dots (QDs) where direct toxicity of these particles and specific entry into bacteria are observed. Effects are similar for planktonic and biofilm bacteria, and biofilm exopolymers do not appear to reduce bioavailability to cells. QDs are taken up whole, retained, but also partially broken down in cells. While nano-TiO2 does not appear to enter cells, negative effects on growth are observed; effects of bacteria on TiO2 agglomerate stability are also observed which could impact nanomaterial transport in the environment. Soil microcosm studies suggest that nano-TiO2 is bioavailable to bacteria as effects on bacterial communities are observed. Taken together, these data support that nanoparticles can affect microorganisms, and thus the processes that they catalyze, and that such effects could manifest in the environment. Still weakly understood are actual environmental exposure levels, and controlling effects mechanisms under environmental conditions.

  7. Using photometrically selected metal-poor stars to study dwarf galaxies and the Galactic stellar halo

    NASA Astrophysics Data System (ADS)

    Youakim, Kris; Starkenburg, Else; Martin, Nicolas; Pristine Team

    2018-06-01

    The Pristine survey is a narrow-band photometric survey designed to efficiently search for extremely metal-poor (EMP) stars. In the first three years of the survey, it has demonstrated great efficiency at finding EMP stars, and also great promise for increasing the current, small sample of the most metal-poor stars. The present sky coverage is ~2500 square degrees in the Northern Galactic Halo, including several individual fields targeting dwarf galaxies. By efficiently identifying member stars in the outskirts of known faint dwarf galaxies, the dynamical histories and chemical abundance patterns of these systems can be understood in greater detail. Additionally, with reliable photometric metallicities over a large sky coverage it is possible to perform a large scale clustering analysis in the Milky Way halo, and investigate the characteristic scale of substructure at different metallicities. This can reveal important details about the process of building up the halo through dwarf galaxy accretion, and offer insight into the connection between dwarf galaxies and the Milky Way halo. In this talk I will outline our results on the search for the most pristine stars, with a focus on how we are using this information to advance our understanding of dwarf galaxies and their contribution to the formation of the Galactic stellar halo.

  8. Molecular mechanism of polymer-assisting supersaturation of poorly water-soluble loratadine based on experimental observations and molecular dynamic simulations.

    PubMed

    Zhang, Shenwu; Sun, Mengchi; Zhao, Yongshan; Song, Xuyang; He, Zhonggui; Wang, Jian; Sun, Jin

    2017-10-01

    Polymers have been usually used to retard nucleation and crystal growth in order to maintain supersaturation, yet their roles in inhibition of nucleation and crystal growth are poorly understood. In our work, the polymer-based supersaturation performances and molecular mechanisms of poorly aqueous soluble loratadine were investigated. Two common hydrophilic polymers (hydroxylpropylmethyl cellulose acetate succinate (HPMC-AS) and poly(vinylpyrrolidone-co-vinyl-acetate) (PVP-VA)) were used. It was found that HPMC-AS was a better polymer to prevent drug molecules from aggregation and to maintain the supersaturated state in solution than PVP-VA. The in vitro dissolution experiments showed that HPMC-AS solid dispersions had more rapid release at pH 4.5 and 6.8 media than PVP-VA solid dispersions under the un-sink condition. Moreover, molecular dynamic simulation results showed that HPMC-AS was more firmly absorbed onto a surface of the drug nanoparticles than PVP-VA due to bigger hydrophobic areas of HPMC-AS. Thereby, crystallization process of loratadine was inhibited in the presence of water to provide prolonged stability of the supersaturated state. In conclusion, polymers played a key role in maintaining supersaturation state of loratadine solid dispersions by strong drug-polymer interactions and the hydrophobic characteristic of polymers.

  9. Mature clustered, regularly interspaced, short palindromic repeats RNA (crRNA) length is measured by a ruler mechanism anchored at the precursor processing site.

    PubMed

    Hatoum-Aslan, Asma; Maniv, Inbal; Marraffini, Luciano A

    2011-12-27

    Precise RNA processing is fundamental to all small RNA-mediated interference pathways. In prokaryotes, clustered, regularly interspaced, short palindromic repeats (CRISPR) loci encode small CRISPR RNAs (crRNAs) that protect against invasive genetic elements by antisense targeting. CRISPR loci are transcribed as a long precursor that is cleaved within repeat sequences by CRISPR-associated (Cas) proteins. In many organisms, this primary processing generates crRNA intermediates that are subject to additional nucleolytic trimming to render mature crRNAs of specific lengths. The molecular mechanisms underlying this maturation event remain poorly understood. Here, we defined the genetic requirements for crRNA primary processing and maturation in Staphylococcus epidermidis. We show that changes in the position of the primary processing site result in extended or diminished maturation to generate mature crRNAs of constant length. These results indicate that crRNA maturation occurs by a ruler mechanism anchored at the primary processing site. We also show that maturation is mediated by specific cas genes distinct from those genes involved in primary processing, showing that this event is directed by CRISPR/Cas loci.

  10. The Arabidopsis EIN2 restricts organ growth by retarding cell expansion

    PubMed Central

    Feng, Guanping; Liu, Gang; Xiao, Jianhua

    2015-01-01

    The growth of plant organ to its characteristic size is a fundamental developmental process, but the mechanism is still poorly understood. Plant hormones play a great role in organ size control by modulating cell division and/or cell expansion. ETHYLENE INSENSITVE 2 (EIN2) was first identified by a genetic screen for ethylene insensitivity and is regarded as a central component of ethylene signaling, but its role in cell growth has not been reported. Here we demonstrate that changed expression of EIN2 led to abnormity of cell expansion by morphological and cytological analyses of EIN2 loss-of-function mutants and the overexpressing transgenic plant. Our findings suggest that EIN2 controls final organ size by restricting cell expansion. PMID:26039475

  11. Non-invasive brain stimulation approaches to fibromyalgia pain

    PubMed Central

    Short, Baron; Borckardt, Jeffrey J; George, Mark; Beam, Will; Reeves, Scott T

    2010-01-01

    Fibromyalgia is a poorly understood disorder that likely involves central nervous system sensory hypersensitivity. There are a host of genetic, neuroendocrine and environmental abnormalities associated with the disease, and recent research findings suggest enhanced sensory processing, and abnormalities in central monoamines and cytokines expression in patients with fibromyalgia. The morbidity and financial costs associated with fibromyalgia are quite high despite conventional treatments with antidepressants, anticonvulsants, low-impact aerobic exercise and psychotherapy. Noninvasive brain stimulation techniques, such as transcranial direct current stimulation, transcranial magnetic stimulation, and electroconvulsive therapy are beginning to be studied as possible treatments for fibromyalgia pain. Early studies appear promising but more work is needed. Future directions in clinical care may include innovative combinations of noninvasive brain stimulation, pharmacological augmentation, and behavior therapies. PMID:21841959

  12. Tidal Forces as Drivers of Collisional Evolution

    NASA Technical Reports Server (NTRS)

    Asphaug, E.; Agnor, C.; Williams, Q.

    2005-01-01

    Planetary collisions are usually understood as shock-related phenomena, analogous to impact cratering. But at large scales, where the impact timescale is comparable to the gravitational timescale, collisions can be dominated by gravitational torques and disruptive tides. Shock physics fares poorly, in many respects, in explaining asteroid and meteorite genesis. Melts, melt residues, welded agglomerates and hydrous and gasrich phases among meteorites lead to an array of diverse puzzles whose solution might be explained, in part, by the thermomechanics of tidal unloading. Comet Shoemaker-Levy 9 disrupted in a process that is common in the present and ancestral solar system, so here we consider specific effects tidal disruption had on the evolution of asteroids, comets and meteorites the unaccreted residues of planet formation.

  13. How do intake clinicians use patient characteristics to select treatment for patients with personality disorders?

    PubMed

    van Manen, Janine; Kamphuis, Jan Henk; Visbach, Geny; Ziegler, Uli; Gerritsen, Ad; Van Rossum, Bert; Rijnierse, Piet; Timman, Reinier; Verheul, Roel

    2008-11-01

    Treatment selection in clinical practice is a poorly understood, often largely implicit decision process, perhaps especially for patients with personality disorders. This study, therefore, investigated how intake clinicians use information about patient characteristics to select psychotherapeutic treatment for patients with personality disorder. A structured interview with a forced-choice format was administered to 27 experienced intake clinicians working in five specialist mental health care institutes in the Netherlands. Substantial consensus was evident among intake clinicians. The results revealed that none of the presented patient characteristics were deemed relevant for the selection of the suitable treatment setting. The appropriate duration and intensity are selected using severity or personal strength variables. The theoretical orientation is selected using personal strength variables.

  14. Control of transcriptional pausing by biased thermal fluctuations on repetitive genomic sequences

    PubMed Central

    Imashimizu, Masahiko; Afek, Ariel; Takahashi, Hiroki; Lubkowska, Lucyna; Lukatsky, David B.

    2016-01-01

    In the process of transcription elongation, RNA polymerase (RNAP) pauses at highly nonrandom positions across genomic DNA, broadly regulating transcription; however, molecular mechanisms responsible for the recognition of such pausing positions remain poorly understood. Here, using a combination of statistical mechanical modeling and high-throughput sequencing and biochemical data, we evaluate the effect of thermal fluctuations on the regulation of RNAP pausing. We demonstrate that diffusive backtracking of RNAP, which is biased by repetitive DNA sequence elements, causes transcriptional pausing. This effect stems from the increased microscopic heterogeneity of an elongation complex, and thus is entropy-dominated. This report shows a linkage between repetitive sequence elements encoded in the genome and regulation of RNAP pausing driven by thermal fluctuations. PMID:27830653

  15. The formation conditions of chondrules and chondrites

    USGS Publications Warehouse

    Alexander, C.M. O'D.; Grossman, Jeffrey N.; Ebel, D.S.; Ciesla, F.J.

    2008-01-01

    Chondrules, which are roughly millimeter-sized silicate-rich spherules, dominate the most primitive meteorites, the chondrites. They formed as molten droplets and, judging from their abundances in chondrites, are the products of one of the most energetic processes that operated in the early inner solar system. The conditions and mechanism of chondrule formation remain poorly understood. Here we show that the abundance of the volatile element sodium remained relatively constant during chondrule formation. Prevention of the evaporation of sodium requires that chondrules formed in regions with much higher solid densities than predicted by known nebular concentration mechanisms. These regions would probably have been self-gravitating. Our model explains many other chemical characteristics of chondrules and also implies that chondrule and planetesimal formation were linked.

  16. Tracking the global footprint of fisheries

    NASA Astrophysics Data System (ADS)

    Kroodsma, David A.; Mayorga, Juan; Hochberg, Timothy; Miller, Nathan A.; Boerder, Kristina; Ferretti, Francesco; Wilson, Alex; Bergman, Bjorn; White, Timothy D.; Block, Barbara A.; Woods, Paul; Sullivan, Brian; Costello, Christopher; Worm, Boris

    2018-02-01

    Although fishing is one of the most widespread activities by which humans harvest natural resources, its global footprint is poorly understood and has never been directly quantified. We processed 22 billion automatic identification system messages and tracked >70,000 industrial fishing vessels from 2012 to 2016, creating a global dynamic footprint of fishing effort with spatial and temporal resolution two to three orders of magnitude higher than for previous data sets. Our data show that industrial fishing occurs in >55% of ocean area and has a spatial extent more than four times that of agriculture. We find that global patterns of fishing have surprisingly low sensitivity to short-term economic and environmental variation and a strong response to cultural and political events such as holidays and closures.

  17. Molecular aspects of defence priming.

    PubMed

    Conrath, Uwe

    2011-10-01

    Plants can be primed for more rapid and robust activation of defence to biotic or abiotic stress. Priming follows perception of molecular patterns of microbes or plants, recognition of pathogen-derived effectors or colonisation by beneficial microbes. However the process can also be induced by treatment with some natural or synthetic compounds and wounding. The primed mobilization of defence is often associated with development of immunity and stress tolerance. Although the phenomenon has been known for decades, the molecular basis of priming is poorly understood. Here, I summarize recent progress made in unravelling molecular aspects of defence priming that is the accumulation of dormant mitogen-activated protein kinases, chromatin modifications and alterations of primary metabolism. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. A Southern Ocean trigger for Northwest Pacific ventilation during the Holocene?

    NASA Astrophysics Data System (ADS)

    Rella, S. F.; Uchida, M.

    2014-02-01

    Holocene ocean circulation is poorly understood due to sparsity of dateable marine archives with submillennial-scale resolution. Here we present a record of mid-depth water radiocarbon contents in the Northwest (NW) Pacific Ocean over the last 12.000 years, which shows remarkable millennial-scale variations relative to changes in atmospheric radiocarbon inventory. Apparent decoupling of these variations from regional ventilation and mixing processes leads us to the suggestion that the mid-depth NW Pacific may have responded to changes in Southern Ocean overturning forced by latitudinal displacements of the southern westerly winds. By inference, a tendency of in-phase related North Atlantic and Southern Ocean overturning would argue against the development of a steady bipolar seesaw regime during the Holocene.

  19. A Southern Ocean trigger for Northwest Pacific ventilation during the Holocene?

    PubMed

    Rella, S F; Uchida, M

    2014-02-17

    Holocene ocean circulation is poorly understood due to sparsity of dateable marine archives with submillennial-scale resolution. Here we present a record of mid-depth water radiocarbon contents in the Northwest (NW) Pacific Ocean over the last 12.000 years, which shows remarkable millennial-scale variations relative to changes in atmospheric radiocarbon inventory. Apparent decoupling of these variations from regional ventilation and mixing processes leads us to the suggestion that the mid-depth NW Pacific may have responded to changes in Southern Ocean overturning forced by latitudinal displacements of the southern westerly winds. By inference, a tendency of in-phase related North Atlantic and Southern Ocean overturning would argue against the development of a steady bipolar seesaw regime during the Holocene.

  20. 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.

  1. Ionospheric Composition and Reactions: Our present knowledge of what ions are in the ionosphere, and why, is summarized.

    PubMed

    Donahue, T M

    1968-02-02

    Recent measurements of ion densities in the ionosphere seem to be more or less compatible with current data for ion-molecule reaction rates in some parts of the ionosphere under conditions in which a steady state prevails. There is no such agreement for the upper ionosphere, where the densities of He(+) and H(+) are difficult to understand in terms of present concepts concerning the relevant production and loss processes. Sources of ionizing radiation are needed to explain night- time observations in the E region and perhaps also in the F region. The D region remains a poorly understood laboratory of negative-ion and positiveion chemistry, where neither observation nor theory is as yet adequate.

  2. Early microbial biofilm formation on marine plastic debris.

    PubMed

    Lobelle, Delphine; Cunliffe, Michael

    2011-01-01

    An important aspect of the global problem of plastic debris pollution is plastic buoyancy. There is some evidence that buoyancy is influenced by attached biofilms but as yet this is poorly understood. We submerged polyethylene plastic in seawater and sampled weekly for 3 weeks in order to study early stage processes. Microbial biofilms developed rapidly on the plastic and coincided with significant changes in the physicochemical properties of the plastic. Submerged plastic became less hydrophobic and more neutrally buoyant during the experiment. Bacteria readily colonised the plastic but there was no indication that plastic-degrading microorganisms were present. This study contributes to improved understanding of the fate of plastic debris in the marine environment. Copyright © 2010 Elsevier Ltd. All rights reserved.

  3. Rivers of the Andes and the Amazon Basin: Deciphering global change from the hydroclimatic variability in the critical zone

    NASA Astrophysics Data System (ADS)

    Moreira-Turcq, Patricia; Carlo Espinoza, Jhan; Filizola, Naziano; Martinez, Jean-Michel

    2018-01-01

    The Critical Zone has been defined as the thin layer of the continental surfaces extending from fresh bedrock and the bottom of groundwater up to vegetation canopy, where soil, rock, water, air, and living organisms interact (Banwart et al., 2012; Lin et al., 2011). Despite the Critical Zone's importance to terrestrial life, it remains poorly understood. In this context, understanding the complex interactions between physical, chemical, and biological processes of the Critical Zone requires long-term observations (Anderson et al., 2012; Brantley et al., 2017), not only because different mechanisms have varying time frames, but also because it is necessary to monitor its natural and anthropogenic evolution in response to global climate and environmental changes.

  4. Science to Practice: Killing Dormant Cells-Is Targeting Autophagy the Key to Complete Tumor Response in Transarterial Chemoembolization?

    PubMed

    Savic, Lynn Jeanette; Chapiro, Julius; Geschwind, Jean-François

    2017-06-01

    In this issue of Radiology, Gade et al ( 1 ) describe a unique mechanism of hepatocellular carcinoma (HCC) cells for surviving ischemia induced by transarterial embolization (TAE)/transarterial chemoembolization (TACE) in a state of cell cycle arrest-a function that may serve as a defensive shield against conventional chemotherapeutic agents. This finding adds to our knowledge and establishes a previously poorly understood mechanism of chemoresistance in HCC. As the Achilles heel in terms of this process, a concurrent upregulation of autophagic flux as an adaptive response to TAE-like ischemia was found by the authors. This is a targetable mechanism that can potentially be exploited for combined therapeutic approaches of embolotherapy and autophagy inhibition in HCC.

  5. Mathematical Modeling of the Origins of Life

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew

    2006-01-01

    The emergence of early metabolism - a network of catalyzed chemical reactions that supported self-maintenance, growth, reproduction and evolution of the ancestors of contemporary cells (protocells) was a critical, but still very poorly understood step on the path from inanimate to animate matter. Here, it is proposed and tested through mathematical modeling of biochemically plausible systems that the emergence of metabolism and its initial evolution towards higher complexity preceded the emergence of a genome. Even though the formation of protocellular metabolism was driven by non-genomic, highly stochastic processes the outcome was largely deterministic, strongly constrained by laws of chemistry. It is shown that such concepts as speciation and fitness to the environment, developed in the context of genomic evolution, also held in the absence of a genome.

  6. Transmission of the gut microbiota: spreading of health

    PubMed Central

    Browne, Hilary P.; Neville, B. Anne; Forster, Samuel C.; Lawley, Trevor D.

    2018-01-01

    Transmission of commensal intestinal bacteria between humans could promote health by establishing, maintaining and replenishing microbial diversity in the microbiota of an individual. Unlike pathogens, the routes of transmission for commensal bacteria remain unappreciated and poorly understood, despite the likely commonalities between both. Consequently, broad infection control measures that are designed to prevent pathogen transmission and infection, such as oversanitation and the overuse of antibiotics, may inadvertently affect human health by altering normal commensal transmission. In this Review, we discuss the mechanisms and factors that influence host-to-host transmission of the intestinal microbiota and examine how a better understanding of these processes will identify new approaches to nurture and restore transmission routes that are used by beneficial bacteria. PMID:28603278

  7. Accretion shocks in the laboratory: Design of an experiment to study star formation

    DOE PAGES

    Young, Rachel P.; Kuranz, C. C.; Drake, R. P.; ...

    2017-02-13

    Here, we present the design of a laboratory-astrophysics experiment to study magnetospheric accretion relevant to young, pre-main-sequence stars. Spectra of young stars show evidence of hotspots created when streams of accreting material impact the surface of the star and create shocks. The structures that form during this process are poorly understood, as the surfaces of young stars cannot be spatially resolved. Our experiment would create a scaled "accretion shock" at a major (several kJ) laser facility. The experiment drives a plasma jet (the "accretion stream") into a solid block (the "stellar surface"), in the presence of a parallel magnetic fieldmore » analogous to the star's local field.« less

  8. A Southern Ocean trigger for Northwest Pacific ventilation during the Holocene?

    PubMed Central

    Rella, S. F.; Uchida, M.

    2014-01-01

    Holocene ocean circulation is poorly understood due to sparsity of dateable marine archives with submillennial-scale resolution. Here we present a record of mid-depth water radiocarbon contents in the Northwest (NW) Pacific Ocean over the last 12.000 years, which shows remarkable millennial-scale variations relative to changes in atmospheric radiocarbon inventory. Apparent decoupling of these variations from regional ventilation and mixing processes leads us to the suggestion that the mid-depth NW Pacific may have responded to changes in Southern Ocean overturning forced by latitudinal displacements of the southern westerly winds. By inference, a tendency of in-phase related North Atlantic and Southern Ocean overturning would argue against the development of a steady bipolar seesaw regime during the Holocene. PMID:24509792

  9. Processes of change in a school-based mindfulness programme: cognitive reactivity and self-coldness as mediators.

    PubMed

    Van der Gucht, Katleen; Takano, Keisuke; Raes, Filip; Kuppens, Peter

    2018-05-01

    The underlying mechanisms of the effectiveness of mindfulness-based interventions for emotional well-being remain poorly understood. Here, we examined the potential mediating effects of cognitive reactivity and self-compassion on symptoms of depression, anxiety and stress using data from an earlier randomised controlled school trial. A moderated time-lagged mediation model based on multilevel modelling was used to analyse the data. The findings showed that post-treatment changes in cognitive reactivity and self-coldness, an aspect of self-compassion, mediated subsequent changes in symptoms of depression, anxiety and stress. These results suggest that cognitive reactivity and self-coldness may be considered as transdiagnostic mechanisms of change of a mindfulness-based intervention programme for youth.

  10. Yersinia vs. host Immunity: how a pathogen evades or triggers a protective response

    PubMed Central

    Chung, Lawton K.; Bliska, James B.

    2015-01-01

    The human pathogenic Yersinia species cause diseases that represent a significant source of morbidity and mortality. Despite this, specific mechanisms underlying Yersinia pathogenesis and protective host responses remain poorly understood. Recent studies have shown that Yersinia disrupt cell death pathways, perturb inflammatory processes and exploit immune cells to promote disease. The ensuing host responses following Yersinia infection include coordination of innate and adaptive immune responses in an attempt to control bacterial replication. Here, we highlight current advances in our understanding of the interactions between the pathogenic yersiniae and host cells, as well as the protective host responses mobilized to counteract these pathogens. Together, these studies enhance our understanding of Yersinia pathogenesis and highlight the ongoing battle between host and microbe. PMID:26638030

  11. Social Motor Synchronization: Insights for Understanding Social Behavior in Autism.

    PubMed

    Fitzpatrick, Paula; Romero, Veronica; Amaral, Joseph L; Duncan, Amie; Barnard, Holly; Richardson, Michael J; Schmidt, R C

    2017-07-01

    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 assessments of ASD traits. We found (a) spontaneous social motor synchronization was associated with responding to joint attention, cooperation, and theory of mind while intentional social motor synchronization was associated with initiating joint attention and theory of mind; and (b) social motor synchronization was associated with ASD severity but not fully explained by motor problems. Findings suggest that objective measures of social motor synchronization may provide insights into understanding ASD traits.

  12. 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.

  13. GlacierRocks - Glacier-Headwall Interaction and its Influence on Rockfall Activity

    NASA Astrophysics Data System (ADS)

    Hartmeyer, Ingo; Keuschnig, Markus; Krautblatter, Michael; Helfricht, Kay; Leith, Kerry; Otto, Jan-Christoph

    2017-04-01

    Climate models predict continued climate warming and a decrease of Austrian glaciers to less than 20% of their present area by the end of this century. Rockfall from freshly exposed headwalls has been documented as an increasing risk factor with considerable significance for man and high-alpine infrastructure. Recent findings of a five-year terrestrial laserscanning campaign (2011-2016) monitoring glacial headwalls at the Kitzsteinhorn (3.203 m a.s.l.), Hohe Tauern Range, Austria, show the dramatic impact of glacier thinning on adjacent headwalls: 80 % of the detected rockfall volumes were triggered from areas located less than 20 m above the current glacier surface. Despite these implications, little is known about the thermal, mechanical and hydrological processes that operate at the glacier-headwall interface (randkluft). Systemic in-situ monitoring of stability-relevant parameters are lacking, leaving fundamental gaps in the understanding of rockfall preconditioning in glacial headwalls and the geomorphological evolution of glaciated catchments. In this contribution we introduce the recently approved research project 'GlacierRocks', which starts in 2017 and will run for at least three years. 'GlacierRocks' will establish the worldwide first research site for long-term monitoring of stability-relevant processes inside a randkluft system. Based on the acquired monitoring data 'GlacierRocks' is pursuing three overall aims at (1) gaining a better understanding of rockfall preconditioning in randklufts and related geomorphological shaping of headwalls, (2) analyzing poorly understood glacial thinning dynamics near headwalls, and (3) estimating present and future rockfall hazard potential in headwalls on a regional scale. The three system components (headwall, glacier, randkluft) will be investigated by combining geomorphological, glaciological and meteorological methods. 'GlacierRocks' will continuously monitor rock temperature, rock moisture, frost cracking, glacier ice temperature, glacier ice motion, randkluft depth/width changes and a series of meteorological parameters. The study site of 'GlacierRocks' is located in the summit region of the Kitzsteinhorn (3.203 m a.s.l.), which is home to an interdisciplinary Open Air Lab (OPAL) focusing on permafrost and rockfall monitoring. Utilizing the existing infrastructure of the OPAL and collaborating with several Kitzsteinhorn-based partner projects, 'GlacierRocks' will make a concerted effort to shed light on poorly understood processes operating at the transition zone between subglacial and subaerial process domains.

  14. 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...

  15. 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...

  16. 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...

  17. 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…

  18. 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.

  19. Emotional and cognitive social processes are impaired in Parkinson's disease and are related to behavioral disorders.

    PubMed

    Narme, Pauline; Mouras, Harold; Roussel, Martine; Duru, Cécile; Krystkowiak, Pierre; Godefroy, Olivier

    2013-03-01

    Parkinson's disease (PD) is associated with behavioral disorders that can affect social functioning but are poorly understood. Since emotional and cognitive social processes are known to be crucial in social relationships, impairment of these processes may account for the emergence of behavioral disorders. We used a systematic battery of tests to assess emotional processes and social cognition in PD patients and relate our findings to conventional neuropsychological data (especially behavioral disorders). Twenty-three PD patients and 46 controls (matched for age and educational level) were included in the study and underwent neuropsychological testing, including an assessment of the behavioral and cognitive components of executive function. Emotional and cognitive social processes were assessed with the Interpersonal Reactivity Index caregiver-administered questionnaire (as a measure of empathy), a facial emotion recognition task and two theory of mind (ToM) tasks. When compared with controls, PD patients showed low levels of empathy (p = .006), impaired facial emotion recognition (which persisted after correction for perceptual abilities) (p = .001), poor performance in a second-order ToM task (p = .008) that assessed both cognitive (p = .004) and affective (p = .03) inferences and, lastly, frequent dysexecutive behavioral disorders (in over 40% of the patients). Overall, impaired emotional and cognitive social functioning was observed in 17% of patients and was related to certain cognitive dysexecutive disorders. In terms of behavioral dysexecutive disorders, social behavior disorders were related to impaired emotional and cognitive social functioning (p = .04) but were independent of cognitive impairments. Emotional and cognitive social processes were found to be impaired in Parkinson's disease. This impairment may account for the emergence of social behavioral disorders. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  20. Preservation of organic matter in nontronite against iron redox cycling.

    NASA Astrophysics Data System (ADS)

    Zeng, Q.

    2015-12-01

    It is generally believed that clay minerals can protect organic matter from degradation in redox active environments, but both biotic and abiotic factors can influence the redox process and thus potentially change the clay-organic associations. However, the specific mechanisms involved in this process remain poorly understood. In this study, a model organic compound, 12-Aminolauric acid (ALA) was selected to intercalate into the structural interlayer of nontronite (an iron-rich smectite, NAu-2) to form an ALA-intercalated NAu-2 composite (ALA-NAu-2). Shawanella putrefaciens CN32 and sodium dithionite were used to reduce structural Fe(III) to Fe(II) in NAu-2 and ALA-NAu-2. The bioreduced ALA-NAu-2 was subsequently re-oxidized by air. The rates and extents of bioreduction and air re-oxidation were determined with wet chemistry methods. ALA release from ALA-NAu-2 via redox process was monitored. Mineralogical changes after iron redox cycle were investigated with X-ray diffraction, infrared spectroscopy, and scanning and transmission electron microscopy. At the beginning stage of bioreduction, S. putrefaciens CN32 reduced Fe(III) from the edges of nontronite and preferentially reduced and dissolved small and poorly crystalline particles, and released ALA, resulting a positive correlation between ALA release and iron reduction extent (<12%). The subsequent bioreduction (reduction extent ranged from 12~30%) and complete air re-oxidation showed no effect on ALA release. These results suggest that released ALA was largely from small and poorly crystalline NAu-2 particles. In contrast to bioreduction, chemical reduction did not exhibit any selectivity in reducing ALA-NAu-2 particles, and a considerable amount of reductive dissolution was responsible for a large amount of ALA release (>80%). Because bacteria are the principal agent for mediating redox process in natural environments, our results demonstrated that the structural interlayer of smectite can serve as a potential shelter to protect organic matter from oxidation.

  1. The introduction of new vaccines into developing countries. III. The role of intellectual property.

    PubMed

    Mahoney, Richard T; Pablos-Mendez, Ariel; Ramachandran, S

    2004-01-26

    The development of new vaccines that address the particular needs of developing countries has been proceeding slowly. A number of new public sector vaccine research and development initiatives have been launched to address this problem. These new initiatives find that they often wish to collaborate with the private sector and, in collaborating with the private sector, they must address issues of intellectual property (IP) management. It has not been well understood why IP management is important and how such management by public sector groups can best be conducted. IP management has become very important because vaccine research and development is driven by the regulatory process. The regulatory process has increased the cost of vaccine development to very high levels especially for the highly sophisticated new vaccines currently under development. Thus, investors seek IP protection for the required large investments. Conversely, we assert this concept as a new insight, IP rights are essential for mobilizing the significant funds necessary to meet regulatory requirements. Thus, IP rights are of value not only for investors but also for the public at large. In the absence of public sector mechanisms to carry out the functions that the private sector currently conducts, the public sector needs to increase its sophistication in IP management and needs to identify and implement strategies that will help the public sector to achieve its public health goals, especially for the poor and, among these individuals, the poor in developing countries. This paper suggests some strategies that might be used by the public sector to help achieve its public health goals, especially for the poor.

  2. Na, K-ATPase subunits as markers for epithelial-mesenchymal transition in cancer and fibrosis

    PubMed Central

    Rajasekaran, Sigrid A.; Huynh, Thu P.; Wolle, Daniel G.; Espineda, Cromwell E.; Inge, Landon J.; Skay, Anna; Lassman, Charles; Nicholas, Susanne B.; Harper, Jeffrey F.; Reeves, Anna E.; Ahmed, Mansoor M.; Leatherman, James M; Mullin, James M.; Rajasekaran, Ayyappan K.

    2010-01-01

    Epithelial-to-mesenchymal transition (EMT) is an important developmental process, participates in tissue repair and occurs during pathological processes of tumor invasiveness, metastasis and tissue fibrosis. The molecular mechanisms leading to EMT are poorly understood. While it is well documented that transforming growth factor (TGF)-β plays a central role in the induction of EMT, the targets of TGF-β signaling are poorly defined. We have shown earlier that Na,K-ATPase β1-subunit levels are highly reduced in poorly differentiated kidney carcinoma cells in culture and in patients’ tumor samples. In this study, we provide evidence that Na,K-ATPase is a new target of TGF-β1-mediated EMT in renal epithelial cells, a model system used in studies of both cancer progression and fibrosis. We show that following treatment with TGF-β1 the surface expression of the β1-subunit of Na,K-ATPase is reduced, prior to well-characterized EMT markers and is associated with the acquisition of a mesenchymal phenotype. RNAi mediated knockdown confirmed the specific involvement of the Na,K-ATPase β1-subunit in the loss of the epithelial phenotype and exogenous over-expression of the Na,K-ATPase β1-subunit attenuated TGF-β1-mediated EMT. We further show that both Na,K-ATPase α- and β-subunit levels are highly reduced in renal fibrotic tissues. These findings for the first time reveal that Na,K-ATPase is a target of TGF-β1-mediated EMT and is associated with the progression of EMT in both cancer and fibrosis. PMID:20501797

  3. 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.

  4. Environmental Stress-mediated EPS Production Shape Microbial Activity on Various Hydrated Rough Surfaces

    NASA Astrophysics Data System (ADS)

    Wang, G.; Liu, L.; Chen, G.

    2016-12-01

    The complex environmental physical and chemical processes and interplay with the associating biological responses are keys to understanding the environmental microbiology ensconced in environmental remediation, water quality control, food safety, nutrient cycling, and etc., yet remain poorly understood. Using experimental micromodels, we study how environmental conditions (e.g., hydration fluctuation, nutrient limitation, pH variation, etc.) affect microbial extracellular polymeric substances (EPS) production and their configuration within various hydrated surfaces, and impacts on microbial motility, surface attachment, aggregation, and other bioremediation activities. To elucidate the potential mechanisms underlying the complex bio-physicochemical processes, we developed an individual-based and spatio-temporally resolved modeling platform that explicitly considers microscale aqueous-phase configuration and nutrient transport/diffusion and associated biophysical processes affecting individual microbial cell life history. We quantitatively explore the effects of the above microscale environmental processes on bio-physicochemical interactions affecting microbial growth, motility, surface attachment and aggregation, and shaping population interactions and functions. Simulation scenarios of microbial induced pollutant (e.g., roxarsone) biotransformation on various hydrated rough surfaces will also be present.

  5. Effects of Plant Traits on Ecosystem and Regional Processes: a Conceptual Framework for Predicting the Consequences of Global Change

    PubMed Central

    CHAPIN, F. STUART

    2003-01-01

    Human activities are causing widespread changes in the species composition of natural and managed ecosystems, but the consequences of these changes are poorly understood. This paper presents a conceptual framework for predicting the ecosystem and regional consequences of changes in plant species composition. Changes in species composition have greatest ecological effects when they modify the ecological factors that directly control (and respond to) ecosystem processes. These interactive controls include: functional types of organisms present in the ecosystem; soil resources used by organisms to grow and reproduce; modulators such as microclimate that influence the activity of organisms; disturbance regime; and human activities. Plant traits related to size and growth rate are particularly important because they determine the productive capacity of vegetation and the rates of decomposition and nitrogen mineralization. Because the same plant traits affect most key processes in the cycling of carbon and nutrients, changes in plant traits tend to affect most biogeochemical cycling processes in parallel. Plant traits also have landscape and regional effects through their effects on water and energy exchange and disturbance regime. PMID:12588725

  6. Limits of computational biology.

    PubMed

    Bray, Dennis

    2015-01-01

    Are we close to a complete inventory of living processes so that we might expect in the near future to reproduce every essential aspect necessary for life? Or are there mechanisms and processes in cells and organisms that are presently inaccessible to us? Here I argue that a close examination of a particularly well-understood system--that of Escherichia coli chemotaxis--shows we are still a long way from a complete description. There is a level of molecular uncertainty, particularly that responsible for fine-tuning and adaptation to myriad external conditions, which we presently cannot resolve or reproduce on a computer. Moreover, the same uncertainty exists for any process in any organism and is especially pronounced and important in higher animals such as humans. Embryonic development, tissue homeostasis, immune recognition, memory formation, and survival in the real world, all depend on vast numbers of subtle variations in cell chemistry most of which are presently unknown or only poorly characterized. Overcoming these limitations will require us to not only accumulate large quantities of highly detailed data but also develop new computational methods able to recapitulate the massively parallel processing of living cells.

  7. Creative cognition and dopaminergic modulation of fronto-striatal networks: Integrative review and research agenda.

    PubMed

    Boot, Nathalie; Baas, Matthijs; van Gaal, Simon; Cools, Roshan; De Dreu, Carsten K W

    2017-07-01

    Creative cognition is key to human functioning yet the underlying neurobiological mechanisms are sparsely addressed and poorly understood. Here we address the possibility that creative cognition is a function of dopaminergic modulation in fronto-striatal brain circuitries. It is proposed that (i) creative cognition benefits from both flexible and persistent processing, (ii) striatal dopamine and the integrity of the nigrostriatal dopaminergic pathway is associated with flexible processing, while (iii) prefrontal dopamine and the integrity of the mesocortical dopaminergic pathway is associated with persistent processing. We examine this possibility in light of studies linking creative ideation, divergent thinking, and creative problem-solving to polymorphisms in dopamine receptor genes, indirect markers and manipulations of the dopaminergic system, and clinical populations with dysregulated dopaminergic activity. Combined, studies suggest a functional differentiation between striatal and prefrontal dopamine: moderate (but not low or high) levels of striatal dopamine benefit creative cognition by facilitating flexible processes, and moderate (but not low or high) levels of prefrontal dopamine enable persistence-driven creativity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Laser Shock Peening on Zr-based Bulk Metallic Glass and Its Effect on Plasticity: Experiment and Modeling

    NASA Astrophysics Data System (ADS)

    Cao, Yunfeng; Xie, Xie; Antonaglia, James; Winiarski, Bartlomiej; Wang, Gongyao; Shin, Yung C.; Withers, Philip J.; Dahmen, Karin A.; Liaw, Peter K.

    2015-05-01

    The Zr-based bulk metallic glasses (BMGs) are a new family of attractive materials with good glass-forming ability and excellent mechanical properties, such as high strength and good wear resistance, which make them candidates for structural and biomedical materials. Although the mechanical behavior of BMGs has been widely investigated, their deformation mechanisms are still poorly understood. In particular, their poor ductility significantly impedes their industrial application. In the present work, we show that the ductility of Zr-based BMGs with nearly zero plasticity is improved by a laser shock peening technique. Moreover, we map the distribution of laser-induced residual stresses via the micro-slot cutting method, and then predict them using a three-dimensional finite-element method coupled with a confined plasma model. Reasonable agreement is achieved between the experimental and modeling results. The analyses of serrated flows reveal plentiful and useful information of the underlying deformation process. Our work provides an easy and effective way to extend the ductility of intrinsically-brittle BMGs, opening up wider applications of these materials.

  9. Laser shock peening on Zr-based bulk metallic glass and its effect on plasticity: Experiment and modeling

    DOE PAGES

    Cao, Yunfeng; Xie, Xie; Antonaglia, James; ...

    2015-05-20

    The Zr-based bulk metallic glasses (BMGs) are a new family of attractive materials with good glass-forming ability and excellent mechanical properties, such as high strength and excellent wear resistance, which make them candidates for structural and biomedical materials. Although the mechanical behavior of BMGs has been widely investigated, their deformation mechanisms are still poorly understood. In particular, their poor ductility significantly impedes their industrial application. In the present work, we show that the ductility of Zr-based BMGs with nearly zero plasticity is improved by a laser shock peening technique. Moreover, we map the distribution of laser-induced residual stresses via themore » micro-slot cutting method, and then predict them using a three dimensional finite-element method coupled with a confined plasma model. Reasonable agreement is achieved between the experimental and modeling results. The analysis of serrated flow reveals plentiful and useful information of the underlying deformation process. As a result, our work provides an easy and effective way to extend the ductility of intrinsically-brittle BMGs, opening up wider applications of these materials.« less

  10. 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.

  11. 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

  12. 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)

  13. 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.

  14. Changes in assembly processes in soil bacterial communities following a wildfire disturbance.

    PubMed

    Ferrenberg, Scott; O'Neill, Sean P; Knelman, Joseph E; Todd, Bryan; Duggan, Sam; Bradley, Daniel; Robinson, Taylor; Schmidt, Steven K; Townsend, Alan R; Williams, Mark W; Cleveland, Cory C; Melbourne, Brett A; Jiang, Lin; Nemergut, Diana R

    2013-06-01

    Although recent work has shown that both deterministic and stochastic processes are important in structuring microbial communities, the factors that affect the relative contributions of niche and neutral processes are poorly understood. The macrobiological literature indicates that ecological disturbances can influence assembly processes. Thus, we sampled bacterial communities at 4 and 16 weeks following a wildfire and used null deviation analysis to examine the role that time since disturbance has in community assembly. Fire dramatically altered bacterial community structure and diversity as well as soil chemistry for both time-points. Community structure shifted between 4 and 16 weeks for both burned and unburned communities. Community assembly in burned sites 4 weeks after fire was significantly more stochastic than in unburned sites. After 16 weeks, however, burned communities were significantly less stochastic than unburned communities. Thus, we propose a three-phase model featuring shifts in the relative importance of niche and neutral processes as a function of time since disturbance. Because neutral processes are characterized by a decoupling between environmental parameters and community structure, we hypothesize that a better understanding of community assembly may be important in determining where and when detailed studies of community composition are valuable for predicting ecosystem function.

  15. Changes in assembly processes in soil bacterial communities following a wildfire disturbance

    PubMed Central

    Ferrenberg, Scott; O'Neill, Sean P; Knelman, Joseph E; Todd, Bryan; Duggan, Sam; Bradley, Daniel; Robinson, Taylor; Schmidt, Steven K; Townsend, Alan R; Williams, Mark W; Cleveland, Cory C; Melbourne, Brett A; Jiang, Lin; Nemergut, Diana R

    2013-01-01

    Although recent work has shown that both deterministic and stochastic processes are important in structuring microbial communities, the factors that affect the relative contributions of niche and neutral processes are poorly understood. The macrobiological literature indicates that ecological disturbances can influence assembly processes. Thus, we sampled bacterial communities at 4 and 16 weeks following a wildfire and used null deviation analysis to examine the role that time since disturbance has in community assembly. Fire dramatically altered bacterial community structure and diversity as well as soil chemistry for both time-points. Community structure shifted between 4 and 16 weeks for both burned and unburned communities. Community assembly in burned sites 4 weeks after fire was significantly more stochastic than in unburned sites. After 16 weeks, however, burned communities were significantly less stochastic than unburned communities. Thus, we propose a three-phase model featuring shifts in the relative importance of niche and neutral processes as a function of time since disturbance. Because neutral processes are characterized by a decoupling between environmental parameters and community structure, we hypothesize that a better understanding of community assembly may be important in determining where and when detailed studies of community composition are valuable for predicting ecosystem function. PMID:23407312

  16. 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...

  17. 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 ...

  18. 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.

  19. 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...

  20. 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 ...

  1. 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...

  2. 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...

  3. 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 ...

  4. 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

  5. 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…

  6. 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...

  7. 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.…

  8. 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.

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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…

  14. REVIEW OF QUANTITATIVE STANDARDS AND GUIDELINES FOR FUNGI IN INDOOR AIR

    EPA Science Inventory

    Exposure to fungal aerosols clearly causes human disease. However, methods for assessing exposure remain poorly understood, and guidelines for interpreting data are often contradictory. The purposes of this paper are to review and compare existing guidelines for indoor airborne...

  15. 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

  16. From Parasite Encounter to Infection: Multiple-Scale Drivers of Parasite Richness in a Wild Social Primate Population

    NASA Technical Reports Server (NTRS)

    Benavides J. A.; Huchard, E.; Pettorelli, N.; King, A. J.; Brown, M. E.; Archer, C. E.; Appleton, C. C.; Raymond, M.; Cowlishaw, G.

    2011-01-01

    Host parasite diversity plays a fundamental role in ecological and evolutionary processes, yet the factors that drive it are still poorly understood. A variety of processes, operating across a range of spatial scales, are likely to influence both the probability of parasite encounter and subsequent infection. Here, we explored eight possible determinants of parasite richness, comprising rainfall and temperature at the population level, ranging behavior and home range productivity at the group level, and age, sex, body condition, and social rank at the individual level. We used a unique dataset describing gastrointestinal parasites in a terrestrial subtropical vertebrate (chacma baboons, Papio ursinus), comprising 662 faecal samples from 86 individuals representing all age-sex classes across two groups over two dry seasons in a desert population. Three mixed models were used to identify the most important factor at each of the three spatial scales (population, group, individual); these were then standardised and combined in a single, global, mixed model. Individual age had the strongest influence on parasite richness, in a convex relationship. Parasite richness was also higher in females and animals in poor condition, albeit at a lower order of magnitude than age. Finally, with a further halving of effect size, parasite richness was positively correlated to day range and temperature. These findings indicate that a range of factors influence host parasite richness through both encounter and infection probabilities, but that individual-level processes may be more important than those at the group or population level.

  17. Binding of Glutathione to Enterovirus Capsids Is Essential for Virion Morphogenesis

    PubMed Central

    Thibaut, Hendrik Jan; Thys, Bert; Canela, María-Dolores; Aguado, Leire; Wimmer, Eckard; Paul, Aniko; Pérez-Pérez, María-Jesús; van Kuppeveld, Frank J. M.; Neyts, Johan

    2014-01-01

    Enteroviruses (family of the Picornaviridae) cover a large group of medically important human pathogens for which no antiviral treatment is approved. Although these viruses have been extensively studied, some aspects of the viral life cycle, in particular morphogenesis, are yet poorly understood. We report the discovery of TP219 as a novel inhibitor of the replication of several enteroviruses, including coxsackievirus and poliovirus. We show that TP219 binds directly glutathione (GSH), thereby rapidly depleting intracellular GSH levels and that this interferes with virus morphogenesis without affecting viral RNA replication. The inhibitory effect on assembly was shown not to depend on an altered reducing environment. Using TP219, we show that GSH is an essential stabilizing cofactor during the transition of protomeric particles into pentameric particles. Sequential passaging of coxsackievirus B3 in the presence of low GSH-levels selected for GSH-independent mutants that harbored a surface-exposed methionine in VP1 at the interface between two protomers. In line with this observation, enteroviruses that already contained this surface-exposed methionine, such as EV71, did not rely on GSH for virus morphogenesis. Biochemical and microscopical analysis provided strong evidence for a direct interaction between GSH and wildtype VP1 and a role for this interaction in localizing assembly intermediates to replication sites. Consistently, the interaction between GSH and mutant VP1 was abolished resulting in a relocalization of the assembly intermediates to replication sites independent from GSH. This study thus reveals GSH as a novel stabilizing host factor essential for the production of infectious enterovirus progeny and provides new insights into the poorly understood process of morphogenesis. PMID:24722756

  18. Affective context interferes with cognitive control in unipolar depression: An fMRI investigation

    PubMed Central

    Dichter, Gabriel S.; Felder, Jennifer N.; Smoski, Moria J.

    2009-01-01

    Background Unipolar major depressive disorder (MDD) is characterized by aberrant amygdala responses to sad stimuli and poor cognitive control, but the interactive effects of these impairments are poorly understood. Aim To evaluate brain activation in MDD in response to cognitive control stimuli embedded within sad and neutral contexts. Method Fourteen adults with MDD and fifteen matched controls participated in a mixed block/event-related functional magnetic resonance imaging (fMRI) task that presented oddball target stimuli embedded within blocks of sad or neutral images. Results Target events activated similar prefrontal brain regions in both groups. However, responses to target events embedded within blocks of emotional images revealed a clear group dissociation. During neutral blocks, the control group demonstrated greater activation to targets in the midfrontal gyrus and anterior cingulate relative to the MDD group, replicating previous findings of prefrontal hypo-activation in MDD samples to cognitive control stimuli. However, during sad blocks, the MDD group demonstrated greater activation in a number of prefrontal regions, including the mid-, inferior, and orbito-frontal gyri and the anterior cingulate, suggesting that relatively more prefrontal brain activation was required to disengage from the sad images to respond to the target events. Limitations A larger sample size would have provided greater statistical power, and more standardized stimuli would have increased external validity. Conclusions This double dissociation of prefrontal responses to target events embedded within neutral and sad context suggests that MDD impacts not only responses to affective events, but extends to other cognitive processes carried out in the context of affective engagement. This implies that emotional reactivity to sad events in MDD may impact functioning more broadly than previously understood. PMID:18706701

  19. 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...

  20. 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…

  1. 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…

  2. 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...

  3. 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 ...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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…

  16. 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…

  17. 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...

  18. 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…

  19. 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...

  20. 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...

  1. 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.

  2. 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.

  3. 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.

  4. Inhibiting platelet-derived growth factor beta reduces Ewing's sarcoma growth and metastasis in a novel orthotopic human xenograft model.

    PubMed

    Wang, Yong Xin; Mandal, Deendayal; Wang, Suizhau; Hughes, Dennis; Pollock, Raphael E; Lev, Dina; Kleinerman, Eugenie; Hayes-Jordan, Andrea

    2009-01-01

    Despite aggressive therapy, Ewing's sarcoma (ES) patients have a poor five-year overall survival of only 20-40%. Pulmonary metastasis is the most common form of demise in these patients. The pathogenesis of pulmonary metastasis is poorly understood and few orthotopic models exist that allow study of spontaneous pulmonary metastasis in ES. We have developed a novel orthotopic xenograft model in which spontaneous pulmonary metastases develop. While the underlying biology of ES is incompletely understood, in addition to the EWS-FLI-1 mutation, it is known that platelet-derived growth factor receptor beta (PDGFR-beta) is highly expressed in ES. Hypothesizing that PDGFR-beta expression is indicative of a specific role for this receptor protein in ES progression, the effect of PDGFR-beta inhibition on ES growth and metastasis was assessed in this novel orthotopic ES model. Silencing PDGFR-beta reduced spontaneous growth and metastasis in ES. Preclinical therapeutically relevant findings such as these may ultimately lead to new treatment initiatives in ES.

  5. 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.

  6. Using the Co-Production of Knowledge for Developing Realistic Natural Disaster Scenarios for Small-to-Medium Scale Emergency Management Exercises

    NASA Astrophysics Data System (ADS)

    Robinson, T.; Wilson, T. M.; Davies, T. R.; Orchiston, C.; Thompson, J.

    2014-12-01

    Disaster scenarios for Emergency Management (EM) exercises are a widely-used and effective tool for communicating hazard information to policy makers, EM personnel, lifelines operators and communities in general. It is crucial that the scenarios are as realistic as possible. Major disasters however, contain a series of cascading consequences, both environmental and social, which are difficult to model. Consequently, only recently have large-scale exercises included such processes; incorporating these in small- and medium-scale scenarios has yet to be attempted. This study details work undertaken in a recent medium-scale earthquake exercise in New Zealand to introduce such cascading processes into the disaster scenario. Given limited time, data, and funding, we show that the co-production of knowledge between natural disaster scientists, EM personnel, and governance and lifelines organisations can yield detailed, realistic scenarios. Using the co-production process, scenario development was able to identify where the pre-exercise state of knowledge was insufficient. This enabled a focussed research response driven by end-user needs. This found that in general, seismic hazard (ground shaking) and its likely impacts were well known and understood by all parties. However, subsequent landsliding and associated effects were poorly known and understood and their potential impacts unconsidered. Scenario development therefore focussed primarily on understanding these processes and their potential effects. This resulted in cascading hazards being included in a medium-scale NZ exercise for the first time. Further, all participants were able to focus on the potential impacts on their specific sectors, increasing the level of knowledge of cascading processes across all parties. Using group based discussions throughout the design process allowed a detailed scenario to be created, fostered stronger inter-disciplinary relationships, and identified areas for further research. Consequently, further detailed research has begun specifically into the impacts from secondary effects in an effort to further increase resilience to future events.

  7. 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.

  8. Arabidopsis Intracellular NHX-Type Sodium-Proton Antiporters are Required for Seed Storage Protein Processing.

    PubMed

    Ashnest, Joanne R; Huynh, Dung L; Dragwidge, Jonathan M; Ford, Brett A; Gendall, Anthony R

    2015-11-01

    The Arabidopsis intracellular sodium-proton exchanger (NHX) proteins AtNHX5 and AtNHX6 have a well-documented role in plant development, and have been used to improve salt tolerance in a variety of species. Despite evidence that intracellular NHX proteins are important in vacuolar trafficking, the mechanism of this role is poorly understood. Here we show that NHX5 and NHX6 are necessary for processing of the predominant seed storage proteins, and also influence the processing and activity of a vacuolar processing enzyme. Furthermore, we show by yeast two-hybrid and bimolecular fluorescence complementation (BiFC) technology that the C-terminal tail of NHX6 interacts with a component of Retromer, another component of the cell sorting machinery, and that this tail is critical for NHX6 activity. These findings demonstrate that NHX5 and NHX6 are important in processing and activity of vacuolar cargo, and suggest a mechanism by which NHX intracellular (IC)-II antiporters may be involved in subcellular trafficking. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  9. Motivation versus aversive processing during perception.

    PubMed

    Padmala, Srikanth; Pessoa, Luiz

    2014-06-01

    Reward facilitates performance and boosts cognitive performance across many tasks. At the same time, negative affective stimuli interfere with performance when they are not relevant to the task at hand. Yet, the investigation of how reward and negative stimuli impact perception and cognition has taken place in a manner that is largely independent of each other. How reward and negative emotion simultaneously contribute to behavioral performance is currently poorly understood. The aim of the present study was to investigate how the simultaneous manipulation of positive motivational processing (here manipulated via reward) and aversive processing (here manipulated via negative picture viewing) influence behavior during a perceptual task. We tested 2 competing hypotheses about the impact of reward on negative picture viewing. On the one hand, suggestions about the automaticity of emotional processing predict that negative picture interference would be relatively immune to reward. On the other, if affective visual processing is not obligatory, as we have argued in the past, reward may counteract the deleterious effect of more potent negative pictures. We found that reward counteracted the effect of potent, negative distracters during a visual discrimination task. Thus, when sufficiently motivated, participants were able to reduce the deleterious impact of bodily mutilation stimuli.

  10. An Intensive Observation of Calving at Helheim Glacier, East Greenland

    NASA Technical Reports Server (NTRS)

    Holland, David M.; Voytenko, Denis; Christianson, Knut; Dixon, Timothy H.; Mei, M. Jeffrey; Parizek, Byron R.; Vankova, Irena; Walker, Ryan T.; Walter, Jacob I.; Nicholls, Keith; hide

    2016-01-01

    Calving of glacial ice into the ocean from the Greenland Ice Sheet is an important component of global sea-level rise. The calving process itself is relatively poorly observed, understood, and modeled; as such, it represents a bottleneck in improving future global sea-level estimates in climate models. We organized a pilot project to observe the calving process at Helheim Glacier in east Greenland in an effort to better understand it. During an intensive one-week survey, we deployed a suite of instrumentation, including a terrestrial radar interferometer, global positioning system (GPS) receivers, seismometers, tsunameters, and an automated weather station. We were fortunate to capture a calving process and to measure various glaciological, oceanographic, and atmospheric parameters before, during, and after the event. One outcome of our observations is evidence that the calving process actually consists of a number of discrete events, spread out over time, in this instance over at least two days. This time span has implications for models of the process. Realistic projections of future global sea level will depend on an accurate parametrization of calving, and we argue that more sustained observations will be required to reach this objective.

  11. Adaptive management for ecosystem services (j/a) | Science ...

    EPA Pesticide Factsheets

    Management of natural resources for the production of ecosystem services, which are vital for human well-being, is necessary even when there is uncertainty regarding system response to management action. This uncertainty is the result of incomplete controllability, complex internal feedbacks, and non-linearity that often interferes with desired management outcomes, and insufficient understanding of nature and people. Adaptive management was developed to reduce such uncertainty. We present a framework for the application of adaptive management for ecosystem services that explicitly accounts for cross-scale tradeoffs in the production of ecosystem services. Our framework focuses on identifying key spatiotemporal scales (plot, patch, ecosystem, landscape, and region) that encompass dominant structures and processes in the system, and includes within- and cross-scale dynamics, ecosystem service tradeoffs, and management controllability within and across scales. Resilience theory recognizes that a limited set of ecological processes in a given system regulate ecosystem services, yet our understanding of these processes is poorly understood. If management actions erode or remove these processes, the system may shift into an alternative state unlikely to support the production of desired services. Adaptive management provides a process to assess the underlying within and cross-scale tradeoffs associated with production of ecosystem services while proceeding with manage

  12. Social-Emotional Correlates of Early Stage Social Information Processing Skills in Children With and Without Autism Spectrum Disorder.

    PubMed

    Russo-Ponsaran, Nicole M; McKown, Clark; Johnson, Jason K; Allen, Adelaide W; Evans-Smith, Bernadette; Fogg, Louis

    2015-10-01

    Difficulty processing social information is a defining feature of autism spectrum disorder (ASD). Yet the failure of children with ASD to process social information effectively is poorly understood. Using Crick and Dodge's model of social information processing (SIP), this study examined the relationship between social-emotional (SE) skills of pragmatic language, theory of mind, and emotion recognition on the one hand, and early stage SIP skills of problem identification and goal generation on the other. The study included a sample of school-aged children with and without ASD. SIP was assessed using hypothetical social situations in the context of a semistructured scenario-based interview. Pragmatic language, theory of mind, and emotion recognition were measured using direct assessments. Social thinking differences between children with and without ASD are largely differences of quantity (overall lower performance in ASD), not discrepancies in cognitive processing patterns. These data support theoretical models of the relationship between SE skills and SIP. Findings have implications for understanding the mechanisms giving rise to SIP deficits in ASD and may ultimately inform treatment development for children with ASD. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

  13. Self-Referential Processing, Rumination, and Cortical Midline Structures in Major Depression

    PubMed Central

    Nejad, Ayna Baladi; Fossati, Philippe; Lemogne, Cédric

    2013-01-01

    Major depression is associated with a bias toward negative emotional processing and increased self-focus, i.e., the process by which one engages in self-referential processing. The increased self-focus in depression is suggested to be of a persistent, repetitive and self-critical nature, and is conceptualized as ruminative brooding. The role of the medial prefrontal cortex in self-referential processing has been previously emphasized in acute major depression. There is increasing evidence that self-referential processing as well as the cortical midline structures play a major role in the development, course, and treatment response of major depressive disorder. However, the links between self-referential processing, rumination, and the cortical midline structures in depression are still poorly understood. Here, we reviewed brain imaging studies in depressed patients and healthy subjects that have examined these links. Self-referential processing in major depression seems associated with abnormally increased activity of the anterior cortical midline structures. Abnormal interactions between the lateralized task-positive network, and the midline cortical structures of the default mode network, as well as the emotional response network, may underlie the pervasiveness of ruminative brooding. Furthermore, targeting this maladaptive form of rumination and its underlying neural correlates may be key for effective treatment. PMID:24124416

  14. 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.

  15. Effects of post-encoding stress on performance in the DRM false memory paradigm.

    PubMed

    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 memory task) and memory was tested 24 h later. Stress decreased recognition of studied words, while increasing false recognition of semantically related lure words. Moreover, while control subjects remembered true and false words equivalently, stressed subjects remembered more false than true words. These results suggest that stress supports gist memory formation in the DRM task, perhaps by hindering detail-specific processing in the hippocampus. © 2015 Pardilla-Delgado et al.; Published by Cold Spring Harbor Laboratory Press.

  16. Persistent Self-Association of Solute Molecules in Solution.

    PubMed

    Tang, Weiwei; Mo, Huaping; Zhang, Mingtao; Parkin, Sean; Gong, Junbo; Wang, Jingkang; Li, Tonglei

    2017-11-02

    The structural evolvement of a solute determines the crystallization outcome. The self-association mechanism leading to nucleation, however, remains poorly understood. Our current study explored the solution chemistry of a model compound, tolfenamic acid (TFA), in three different solvents mainly by solution NMR. It was found that hydrogen-bonded pairs of solute-solute or solute-solvent stack with each through forming a much weaker π-π interaction as the concentration increases. Depending on the solvent, configurations of the solution species may be retained in the resultant crystal structure or undergo rearrangement. Yet, the π-π stacking is always retained in the crystal regardless of the solvent used for the crystallization. The finding suggests that nucleation not only involves the primary intermolecular interaction (hydrogen bonding) but also engages the secondary forces in the self-assembly process.

  17. Modeling the Provenance of Crater Ejecta

    NASA Astrophysics Data System (ADS)

    Huang, Ya-Huei; Minton, David A.

    2014-11-01

    The cratering history of the Moon provides a way to study the violent early history of our early solar system. Nevertheless, we are still limited in our ability to interpret the lunar cratering history because the complex process of generation and subsequent transportation and destruction of impact melt products is relatively poorly understood. Here we describe a preliminary model for the transport of datable impact melt products by craters over Gy timescales on the lunar surface. We use a numerical model based on the Maxwell Z-model to model the exhumation and transport of ejecta material from within the excavation flow of a transient crater. We describe our algorithm for rapidly estimating the provenance of ejecta material for use in a Monte Carlo cratering code capable of simulating lunar cratering over Gy timescales.

  18. Imaging the distribution of transient viscosity after the 2016 Mw 7.1 Kumamoto earthquake

    NASA Astrophysics Data System (ADS)

    Moore, James D. P.; Yu, Hang; Tang, Chi-Hsien; Wang, Teng; Barbot, Sylvain; Peng, Dongju; Masuti, Sagar; Dauwels, Justin; Hsu, Ya-Ju; Lambert, Valère; Nanjundiah, Priyamvada; Wei, Shengji; Lindsey, Eric; Feng, Lujia; Shibazaki, Bunichiro

    2017-04-01

    The deformation of mantle and crustal rocks in response to stress plays a crucial role in the distribution of seismic and volcanic hazards, controlling tectonic processes ranging from continental drift to earthquake triggering. However, the spatial variation of these dynamic properties is poorly understood as they are difficult to measure. We exploited the large stress perturbation incurred by the 2016 earthquake sequence in Kumamoto, Japan, to directly image localized and distributed deformation. The earthquakes illuminated distinct regions of low effective viscosity in the lower crust, notably beneath the Mount Aso and Mount Kuju volcanoes, surrounded by larger-scale variations of viscosity across the back-arc. This study demonstrates a new potential for geodesy to directly probe rock rheology in situ across many spatial and temporal scales.

  19. Thermal Cycling Fatigue in DIPs Mounted with Eutectic Tin-Lead Solder Joints in Stub and Gullwing Geometries

    NASA Technical Reports Server (NTRS)

    Winslow, J. W.; Silveira, C. de

    1993-01-01

    It has long been known that solder joints under mechanical stress are subject to failure. In early electronic systems, such failures were avoided primarily by avoiding the use of solder as a mechanical structural component. The rule was first to make sound wire connections that did not depend mechanically on solder, and only then to solder them. Careful design and miniaturization in modern electronic systems limits the mechanical stresses exerted on solder joints to values less than their yield points, and these joints have become integral parts of the mechanical structures. Unfortunately, while these joints are strong enough when new, they have proven vulnerable to fatigue failures as they age. Details of the fatigue process are poorly understood, making predictions of expected lifetimes difficult.

  20. Astrocytic Ca2+ responses in the spinal dorsal horn by noxious stimuli to the skin.

    PubMed

    Yoshihara, Kohei; Matsuda, Tsuyoshi; Kohro, Yuta; Tozaki-Saitoh, Hidetoshi; Inoue, Kazuhide; Tsuda, Makoto

    2018-05-03

    The role of astrocytes in the spinal dorsal horn (SDH) for sensory information processing under normal conditions is poorly understood. In this study, we investigated whether SDH astrocytes respond to noxious and innocuous stimuli to the skin of normal mice using in vivo two-photon Ca 2+ imaging under anesthesia. We found that noxious stimulation evoked by intraplantar formalin injection provoked an elevation in intracellular Ca 2+ levels in SDH astrocytes. By contrast, neither instantaneous noxious pinching nor innocuous stimuli (cooling or brushing) to the hindpaw elicited astrocytic Ca 2+ responses. Thus, SDH astrocytes could respond preferentially to a strong and/or sustained noxious stimulus. Copyright © 2018 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  1. Wave Modeling of the Solar Wind.

    PubMed

    Ofman, Leon

    The acceleration and heating of the solar wind have been studied for decades using satellite observations and models. However, the exact mechanism that leads to solar wind heating and acceleration is poorly understood. In order to improve the understanding of the physical mechanisms that are involved in these processes a combination of modeling and observational analysis is required. Recent models constrained by satellite observations show that wave heating in the low-frequency (MHD), and high-frequency (ion-cyclotron) range may provide the necessary momentum and heat input to coronal plasma and produce the solar wind. This review is focused on the results of several recent solar modeling studies that include waves explicitly in the MHD and the kinetic regime. The current status of the understanding of the solar wind acceleration and heating by waves is reviewed.

  2. Distinctive striatal dopamine signaling after dieting and gastric bypass.

    PubMed

    Hankir, Mohammed K; Ashrafian, Hutan; Hesse, Swen; Horstmann, Annette; Fenske, Wiebke K

    2015-05-01

    Highly palatable and/or calorically dense foods, such as those rich in fat, engage the striatum to govern and set complex behaviors. Striatal dopamine signaling has been implicated in hedonic feeding and the development of obesity. Dieting and bariatric surgery have markedly different outcomes on weight loss, yet how these interventions affect central homeostatic and food reward processing remains poorly understood. Here, we propose that dieting and gastric bypass produce distinct changes in peripheral factors with known roles in regulating energy homeostasis, resulting in differential modulation of nigrostriatal and mesolimbic dopaminergic reward circuits. Enhancement of intestinal fat metabolism after gastric bypass may also modify striatal dopamine signaling contributing to its unique long-term effects on feeding behavior and body weight in obese individuals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Physicochemical basis for water-actuated movement and stress generation in nonliving plant tissues.

    PubMed

    Bertinetti, L; Fischer, F D; Fratzl, P

    2013-12-06

    Generating stresses and strains through water uptake from atmospheric humidity is a common process in nature, e.g., in seed dispersal. Actuation depends on a balance between chemical interactions and the elastic energy required to accomplish the volume change. In order to study the poorly understood chemical interactions, we combine mechanosorption experiments with theoretical calculations of the swelling behavior to estimate the mechanical energy and extract the contribution of the chemical energy per absorbed water molecule. The latter is highest in the completely dry state and stays almost constant at about 1.2 kT for higher hydrations. This suggests that water bound to the macromolecular components of the wood tissues acquires one additional hydrogen bond per eight water molecules, thus providing energy for actuation.

  4. Linking Anxiety and Insistence on Sameness in Autistic Children: The Role of Sensory Hypersensitivity.

    PubMed

    Black, Karen R; Stevenson, Ryan A; Segers, Magali; Ncube, Busiswe L; Sun, Sol Z; Philipp-Muller, Aviva; Bebko, James M; Barense, Morgan D; Ferber, Susanne

    2017-08-01

    Sensory hypersensitivity and insistence on sameness (I/S) are common, co-occurring features of autism, yet the relationship between them is poorly understood. This study assessed the impact of sensory hypersensitivity on the clinical symptoms of specific phobia, separation anxiety, social anxiety and I/S for autistic and typically developing (TD) children. Parents of 79 children completed questionnaires on their child's difficulties related to sensory processing, I/S, and anxiety. Results demonstrated that sensory hypersensitivity mediated 67% of the relationship between symptoms of specific phobia and I/S and 57% of the relationship between separation anxiety and I/S. No relationship was observed between sensory hypersensitivity and social anxiety. These mediation effects of sensory hypersensitivity were found only in autistic children, not in TD children.

  5. The molecular basis of plant cell wall extension.

    PubMed

    Darley, C P; Forrester, A M; McQueen-Mason, S J

    2001-09-01

    In all terrestrial and aquatic plant species the primary cell wall is a dynamic structure, adjusted to fulfil a diversity of functions. However a universal property is its considerable mechanical and tensile strength, whilst being flexible enough to accommodate turgor and allow for cell elongation. The wall is a composite material consisting of a framework of cellulose microfibrils embedded in a matrix of non-cellulosic polysaccharides, interlaced with structural proteins and pectic polymers. The assembly and modification of these polymers within the growing cell wall has, until recently, been poorly understood. Advances in cytological and genetic techniques have thrown light on these processes and have led to the discovery of a number of wall-modifying enzymes which, either directly or indirectly, play a role in the molecular basis of cell wall expansion.

  6. What is interesting? Exploring the appraisal structure of interest.

    PubMed

    Silvia, Paul J

    2005-03-01

    Relative to other emotions, interest is poorly understood. On the basis of theories of appraisal process and structure, it was predicted that interest consists of appraisals of novelty (factors related to unfamiliarity and complexity) and appraisals of coping potential (the ability to understand the new, complex thing). Four experiments, using in vivo rather than retrospective methods, supported this appraisal structure. The findings were general across measured and manipulated appraisals, interesting stimuli (random polygons, visual art, poetry), and measures of interest (self-reports, forced-choice, behavioral measures). Furthermore, the appraisal structure was specific to interest (it did not predict enjoyment, a related positive emotion), and appraisals predicted interest beyond relevant traits (curiosity, openness). The appraisal perspective offers a powerful way of construing the causes of interest. Copyright 2005 APA, all rights reserved.

  7. Effect of the fluid core on changes in the length of day due to long period tides

    NASA Technical Reports Server (NTRS)

    Wahr, J. M.; Smith, M. L.; Sasao, T.

    1981-01-01

    The long period luni-solar tidal potential is known to cause periodic changes in the earth's rotation rate. It is found that the effect of a dissipationless fluid outer core is to reduce the amplitudes of these tidal perturbations by about 11 percent. When the fluid core effect is added to Agnew and Farrell's (1978) estimate of the effect of an equilibrium ocean, the result is in accord with observation. The effects of dissipative processes within the fluid core are also examined. Out-of-phase perturbations are found which could be as large as about 10 ms at 18.6 yr. It is concluded, however, that the poorly understood decade fluctuations in the earth's rotation rate will prohibit observation of this effect.

  8. Electron temperature gradient scale at collisionless shocks.

    PubMed

    Schwartz, Steven J; Henley, Edmund; Mitchell, Jeremy; Krasnoselskikh, Vladimir

    2011-11-18

    Shock waves are ubiquitous in space and astrophysics. They transform directed flow energy into thermal energy and accelerate energetic particles. The energy repartition is a multiscale process related to the spatial and temporal structure of the electromagnetic fields within the shock layer. While large scale features of ion heating are known, the electron heating and smaller scale fields remain poorly understood. We determine for the first time the scale of the electron temperature gradient via electron distributions measured in situ by the Cluster spacecraft. Half of the electron heating coincides with a narrow layer several electron inertial lengths (c/ω(pe)) thick. Consequently, the nonlinear steepening is limited by wave dispersion. The dc electric field must also vary over these small scales, strongly influencing the efficiency of shocks as cosmic ray accelerators.

  9. Tracing the Rationale Behind UML Model Change Through Argumentation

    NASA Astrophysics Data System (ADS)

    Jureta, Ivan J.; Faulkner, Stéphane

    Neglecting traceability—i.e., the ability to describe and follow the life of a requirement—is known to entail misunderstanding and miscommunication, leading to the engineering of poor quality systems. Following the simple principles that (a) changes to UML model instances ought be justified to the stakeholders, (b) justification should proceed in a structured manner to ensure rigor in discussions, critique, and revisions of model instances, and (c) the concept of argument instantiated in a justification process ought to be well defined and understood, the present paper introduces the UML Traceability through Argumentation Method (UML-TAM) to enable the traceability of design rationale in UML while allowing the appropriateness of model changes to be checked by analysis of the structure of the arguments provided to justify such changes.

  10. Modeling and Deorphanization of Orphan GPCRs.

    PubMed

    Diaz, Constantino; Angelloz-Nicoud, Patricia; Pihan, Emilie

    2018-01-01

    Despite tremendous efforts, approximately 120 GPCRs remain orphan. Their physiological functions and their potential roles in diseases are poorly understood. Orphan GPCRs are extremely important because they may provide novel therapeutic targets for unmet medical needs. As a complement to experimental approaches, molecular modeling and virtual screening are efficient techniques to discover synthetic surrogate ligands which can help to elucidate the role of oGPCRs. Constitutively activated mutants and recently published active structures of GPCRs provide stimulating opportunities for building active molecular models for oGPCRs and identifying activators using virtual screening of compound libraries. We describe the molecular modeling and virtual screening process we have applied in the discovery of surrogate ligands, and provide examples for CCKA, a simulated oGPCR, and for two oGPCRs, GPR52 and GPR34.

  11. Computational design and multiscale modeling of a nanoactuator using DNA actuation.

    PubMed

    Hamdi, Mustapha

    2009-12-02

    Developments in the field of nanobiodevices coupling nanostructures and biological components are of great interest in medical nanorobotics. As the fundamentals of bio/non-bio interaction processes are still poorly understood in the design of these devices, design tools and multiscale dynamics modeling approaches are necessary at the fabrication pre-project stage. This paper proposes a new concept of optimized carbon nanotube based servomotor design for drug delivery and biomolecular transport applications. The design of an encapsulated DNA-multi-walled carbon nanotube actuator is prototyped using multiscale modeling. The system is parametrized by using a quantum level approach and characterized by using a molecular dynamics simulation. Based on the analysis of the simulation results, a servo nanoactuator using ionic current feedback is simulated and analyzed for application as a drug delivery carrier.

  12. Reconstructing a hydrogen-driven microbial metabolic network in Opalinus Clay rock

    DOE PAGES

    Bagnoud, Alexandre; Chourey, Karuna; Hettich, Robert L.; ...

    2016-10-14

    A significant fraction (~ 20%) of microbial life is found in the terrestrial deep subsurface, yet the metabolic processes extant in those environments are poorly understood. Here we show that H 2, injected into the Opalinus Clay formation in a borehole located 300 meters below the surface, fuels a community of microorganisms with interconnected metabolisms. Metagenomic binning and metaproteomic analysis reveal a complete carbon cycle, driven by autotrophic hydrogen oxidizers. Dead biomass from these organisms is a substrate for a fermenting bacterium that produces acetate as a product. In turn, complete oxidizer heterotrophic sulfate- reducing bacteria utilize acetate and oxidizemore » it to CO 2, closing the cycle. This metabolic reconstruction sheds light onto a hydrogen-driven carbon cycle, and a sunlight-independent ecosystem in the deep subsurface.« less

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

    Volkow, N.D.; Wang, G.; Volkow, N.D.

    A major challenge in understanding substance-use disorders lies in uncovering why some individuals become addicted when exposed to drugs, whereas others do not. Although genetic, developmental, and environmental factors are recognized as major contributors to a person's risk of becoming addicted, the neurobiological processes that underlie this vulnerability are still poorly understood. Imaging studies suggest that individual variations in key dopamine-modulated brain circuits, including circuits involved in reward, memory, executive function, and motivation, contribute to some of the differences in addiction vulnerability. A better understanding of the main circuits affected by chronic drug use and the influence of social stressors,more » developmental trajectories, and genetic background on these circuits is bound to lead to a better understanding of addiction and to more effective strategies for the prevention and treatment of substance-use disorders.« less

  14. Female puberty acceleration by male odour in mice: neural pathway and behavioural consequences.

    PubMed

    Jouhanneau, Mélanie; Szymanski, Laura A; Keller, Matthieu

    2014-08-01

    In female mice, exposure to male chemosignals results in early puberty onset characterized by advanced vaginal opening and higher uterine weight. Evidence suggests that the male chemosignals responsible for acceleration of female puberty are androgen-dependent, but not all of the compounds that contribute to puberty acceleration have been identified. The male chemosignals are primarily detected and processed by the vomeronasal system including the vomeronasal organ, the accessory olfactory bulb and the medial amygdala. By contrast, the mechanism by which this olfactory information is integrated in the hypothalamus is poorly understood. In this context, the recent identification of the neuropeptide kisspeptin as a gatekeeper of puberty onset may provide a good candidate neuropeptide system for the transmission of chemosensory information to the gonadotrope axis.

  15. Air Pollution: Mechanisms of Neuroinflammation & CNS Disease

    PubMed Central

    Block, Michelle L.; Calderón-Garcidueñas, Lilian

    2009-01-01

    Emerging evidence implicates air pollution as a chronic source of neuroinflammation, reactive oxygen species (ROS), and neuropathology instigating central nervous system (CNS) disease. Stroke incidence, and Alzheimer’s and Parkinson’s disease pathology are linked to air pollution. Recent reports reveal that air pollution components reach the brain. Further, systemic effects known to impact lung and cardiovascular disease also impinge upon CNS health. While mechanisms driving air pollution-induced CNS pathology are poorly understood, new evidence suggests that activation of microglia and changes in the blood brain barrier may be key to this process. Here, we summarize recent findings detailing the mechanisms through which air pollution reaches the brain and activates the resident innate immune response to become a chronic source of pro-inflammatory factors and ROS culpable in CNS disease. PMID:19716187

  16. Yersinia versus host immunity: how a pathogen evades or triggers a protective response.

    PubMed

    Chung, Lawton K; Bliska, James B

    2016-02-01

    The human pathogenic Yersinia species cause diseases that represent a significant source of morbidity and mortality. Despite this, specific mechanisms underlying Yersinia pathogenesis and protective host responses remain poorly understood. Recent studies have shown that Yersinia disrupt cell death pathways, perturb inflammatory processes and exploit immune cells to promote disease. The ensuing host responses following Yersinia infection include coordination of innate and adaptive immune responses in an attempt to control bacterial replication. Here, we highlight current advances in our understanding of the interactions between the pathogenic yersiniae and host cells, as well as the protective host responses mobilized to counteract these pathogens. Together, these studies enhance our understanding of Yersinia pathogenesis and highlight the ongoing battle between host and microbe. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. 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...

  18. 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...

  19. 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...

  20. 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 ...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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…

  7. 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...

  8. 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) ...

  9. 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...

  10. 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…

  11. 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...

  12. 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…

  13. 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, ...

  14. 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...

  15. 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…

  16. 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...

  17. 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...

  18. 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)...

  19. 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...

  20. 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…

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