Showing papers by "University of Massachusetts Boston published in 2008"
TL;DR: It is demonstrated that a generic isolated quantum many-body system does relax to a state well described by the standard statistical-mechanical prescription, and it is shown that time evolution itself plays a merely auxiliary role in relaxation, and that thermalization instead happens at the level of individual eigenstates, as first proposed by Deutsch and Srednicki.
Abstract: It is demonstrated that an isolated generic quantum many-body system does relax to a state well described by the standard statistical mechanical prescription The thermalization happens at the level of individual eigenstates, allowing the computation of thermal averages from knowledge of any eigenstate in the microcanonical energy window An understanding of the temporal evolution of isolated many-body quantum systems has long been elusive Recently, meaningful experimental studies1,2 of the problem have become possible, stimulating theoretical interest3,4,5,6,7 In generic isolated systems, non-equilibrium dynamics is expected8,9 to result in thermalization: a relaxation to states in which the values of macroscopic quantities are stationary, universal with respect to widely differing initial conditions, and predictable using statistical mechanics However, it is not obvious what feature of many-body quantum mechanics makes quantum thermalization possible in a sense analogous to that in which dynamical chaos makes classical thermalization possible10 For example, dynamical chaos itself cannot occur in an isolated quantum system, in which the time evolution is linear and the spectrum is discrete11 Some recent studies4,5 even suggest that statistical mechanics may give incorrect predictions for the outcomes of relaxation in such systems Here we demonstrate that a generic isolated quantum many-body system does relax to a state well described by the standard statistical-mechanical prescription Moreover, we show that time evolution itself plays a merely auxiliary role in relaxation, and that thermalization instead happens at the level of individual eigenstates, as first proposed by Deutsch12 and Srednicki13 A striking consequence of this eigenstate-thermalization scenario, confirmed for our system, is that knowledge of a single many-body eigenstate is sufficient to compute thermal averages—any eigenstate in the microcanonical energy window will do, because they all give the same result
2,598 citations
TL;DR: The stages of invasion known as the "invasion pathway" are used to identify 5 nonexclusive consequences of climate change for invasive species and the need for enhanced environmental monitoring and expanded coordination among entities involved in invasive-species management is emphasized.
Abstract: Scientific and societal unknowns make it difficult to predict how global environmental changes such as climate change and biological invasions will affect ecological systems. In the long term, these changes may have interacting effects and compound the uncertainty associated with each individual driver. Nonetheless, invasive species are likely to respond in ways that should be qualitatively predictable, and some of these responses will be distinct from those of native counterparts. We used the stages of invasion known as the "invasion pathway" to identify 5 nonexclusive consequences of climate change for invasive species: (1) altered transport and introduction mechanisms, (2) establishment of new invasive species, (3) altered impact of existing invasive species, (4) altered distribution of existing invasive species, and (5) altered effectiveness of control strategies. We then used these consequences to identify testable hypotheses about the responses of invasive species to climate change and provide suggestions for invasive-species management plans. The 5 consequences also emphasize the need for enhanced environmental monitoring and expanded coordination among entities involved in invasive-species management.
1,130 citations
TL;DR: Clinical assessment of parental stress, acknowledging differences in parenting experiences for mothers and fathers of young children with ASD, is needed.
Abstract: Elevated parenting stress is observed among mothers of older children with autism spectrum disorders (ASD), but little is known about parents of young newly-diagnosed children. Associations between child behavior and parenting stress were examined in mothers and fathers of 54 toddlers with ASD (mean age = 26.9 months). Parents reported elevated parenting stress. Deficits/delays in children's social relatedness were associated with overall parenting stress, parent-child relationship problems, and distress for mothers and fathers. Regulatory problems were associated with maternal stress, whereas externalizing behaviors were associated with paternal stress. Cognitive functioning, communication deficits, and atypical behaviors were not uniquely associated with parenting stress. Clinical assessment of parental stress, acknowledging differences in parenting experiences for mothers and fathers of young children with ASD, is needed.
1,057 citations
TL;DR: In this paper, the authors examine corporate responses to climate change in relation to the development of reporting mechanisms for greenhouse gases, more specifically carbon disclosure, and develop a conceptual framework using theories of global governance, institutional theory and commensuration to understand the role of carbon disclosure in the emerging climate regime.
Abstract: This paper examines corporate responses to climate change in relation to the development of reporting mechanisms for greenhouse gases, more specifically carbon disclosure. It first presents some background and context on the evolution of carbon trading and disclosure, and then develops a conceptual framework using theories of global governance, institutional theory and commensuration to understand the role of carbon disclosure in the emerging climate regime. Subsequently, a closer look is taken at carbon disclosure and reporting mechanisms, with a particular focus on the Carbon Disclosure Project (CDP). Our analysis of responses shows that CDP has been successfully using institutional investors to urge firms to disclose extensive information about their climate change activities. However, although response rates in terms of numbers of disclosing firms are impressive and growing, neither the level of carbon disclosure that CDP promotes nor the more detailed carbon accounting provide information that is particularly valuable for investors, NGOs or policy makers at this stage. As a project of commensuration, carbon disclosure has achieved some progress in technical terms, but much less with regard to the cognitive and value dimensions.
516 citations
Pfizer1, University of Massachusetts Boston2, Brown University3, United States Environmental Protection Agency4, Vanderbilt University Medical Center5, Johns Hopkins University6, Schering-Plough7, American Cancer Society8, National Institute for Occupational Safety and Health9, United States Public Health Service10, North Carolina State University11, University of Massachusetts Lowell12
TL;DR: This research presents a meta-analyses of the immune system’s response to exposure to radiation and shows clear patterns of decline in the immune systems of men and women aged 65 and over.
Abstract: Robert E. Chapin, Jane Adams, Kim Boekelheide, L. Earl Gray Jr, Simon W. Hayward, Peter S.J. Lees, Barry S. McIntyre, Kenneth M. Portier, Teresa M. Schnorr, Sherry G. Selevan, John G. Vandenbergh, and Susan R. Woskie Pfizer, Inc., Groton, CT University of Massachusetts, Boston, MA Brown University, Providence, RI U.S. Environmental Protection Agency, Research Triangle Park, NC Vanderbilt University Medical Center, Nashville, TN Johns Hopkins University, Baltimore, MD Schering Plough Research Institute, Summit, NJ American Cancer Society, Atlanta, GA National Institute for Occupational Safety and Health, Cincinnati, OH U.S. Public Health Service (Ret), Silver Spring, MD North Carolina State University, Raleigh, NC University of Massachusetts, Lowell, MA
489 citations
TL;DR: The authors developed a critical framework on international management and production that draws from the literature on global commodity chains and global production networks, on institutional entrepreneurship, and on neo-Gramscian theory in international political economy.
Abstract: I develop a critical framework on international management and production that draws from the literature on global commodity chains and global production networks, on institutional entrepreneurship, and on neo-Gramscian theory in international political economy The framework views global production networks as integrated economic, political, and discursive systems in which market and political power are intertwined The framework offers insights into contested political and social issues, such as sweatshops and incomes for coffee growers
487 citations
TL;DR: Treatment with an acceptance-based behavioral therapy aimed at increasing acceptance of internal experiences and encouraging action in valued domains for GAD led to statistically significant reductions in clinician-rated and self-reported GAD symptoms that were maintained at 3- and 9-month follow-up assessments.
Abstract: Generalized anxiety disorder (GAD) is a chronic anxiety disorder, associated with comorbidity and impairment in quality of life, for which improved psychosocial treatments are needed. GAD is also associated with reactivity to and avoidance of internal experiences. The current study examined the efficacy of an acceptance-based behavioral therapy aimed at increasing acceptance of internal experiences and encouraging action in valued domains for GAD. Clients were randomly assigned to immediate (n = 15) or delayed (n = 16) treatment. Acceptance-based behavior therapy led to statistically significant reductions in clinician-rated and self-reported GAD symptoms that were maintained at 3- and 9-month follow-up assessments; significant reductions in depressive symptoms were also observed. At posttreatment assessment 78% of treated participants no longer met criteria for GAD and 77% achieved high end-state functioning; these proportions stayed constant or increased over time. As predicted, treatment was associated with decreases in experiential avoidance and increases in mindfulness.
480 citations
TL;DR: Results suggested good agreement among different measures of early language, including direct assessment and parent report measures, and significant concurrent predictors of receptive language included gestures, non-verbal cognitive ability and response to joint attention.
Abstract: One of the primary diagnostic criteria for the diagnosis of autism spectrum disorders (ASD) is the presence of a language delay or impairment. Children with ASD are now being identified at significantly younger ages, and prior research has consistently found that early language skills in this population are heterogeneous and an important predictor for later outcome. The goal of this study was to systematically investigate language in toddlers with ASD and to identify early correlates of receptive and expressive language in this population. The study included 164 toddlers with ASD between the ages of 18 and 33 months who were evaluated on several cognitive, language and behavioral measures. Results suggested good agreement among different measures of early language, including direct assessment and parent report measures. Significant concurrent predictors of receptive language included gestures, non-verbal cognitive ability and response to joint attention. For expressive language, the most significant predictors were non-verbal cognitive ability, gestures and imitation. These findings have important implications for intervention programs targeting this population.
426 citations
National Center for Toxicological Research1, Durham University2, University of Massachusetts Boston3, ICF International4, Center for Drug Evaluation and Research5, Biogen Idec6, SAS Institute7, Applied Biosystems8, Agilent Technologies9, Zhejiang University10, Affymetrix11, Center for Biologics Evaluation and Research12, National Institutes of Health13, Advanced Technology Center14, University of Texas Southwestern Medical Center15, Novartis16, GE Healthcare17, Cedars-Sinai Medical Center18, University of Illinois at Urbana–Champaign19
TL;DR: The results provide practical guidance to choose the appropriate FC and P-value cutoffs when selecting a given number of DEGs and recommend the use of FC-ranking plus a non-stringent P cutoff as a straightforward and baseline practice in order to generate more reproducible DEG lists.
Abstract: Background
Reproducibility is a fundamental requirement in scientific experiments. Some recent publications have claimed that microarrays are unreliable because lists of differentially expressed genes (DEGs) are not reproducible in similar experiments. Meanwhile, new statistical methods for identifying DEGs continue to appear in the scientific literature. The resultant variety of existing and emerging methods exacerbates confusion and continuing debate in the microarray community on the appropriate choice of methods for identifying reliable DEG lists.
404 citations
TL;DR: Data support that HFA/AS in adolescents may be associated with clinically relevant social anxiety symptoms and Behavioural avoidance and evaluative social anxiety increased by age within the H FA/AS group, whereas behavioural avoidance decreased by age in control participants.
Abstract: We examined social anxiety and internalizing symptoms using the Social Phobia and Anxiety Inventory for Children (SPAI-C), the Social Anxiety Scale for Children -Revised (SASC-R), and the Child Behavior Checklist (CBCL) in a sample of fifty-four high-functioning subjects with autism or Asperger syndrome (HFA/AS) (M = 11.2 ± 1.7 years) and 305 community subjects (M = 12.2 ± 2.2 years). Children and adolescents completed the SPAI-C and SASC-R, and their parents completed the CBCL Internalizing scale. Adolescents with HFA/AS scored higher than the community sample on all measures. Behavioural avoidance and evaluative social anxiety increased by age within the HFA/AS group, whereas behavioural avoidance decreased by age in control participants. Data support that HFA/AS in adolescents may be associated with clinically relevant social anxiety symptoms.
389 citations
University of Michigan1, University of Washington2, Boston University3, University of Massachusetts Boston4, University of Colorado Boulder5, University of Utah6, University of Rochester7, University of California, Los Angeles8, University of California, Davis9, Kennedy Krieger Institute10, University of California, Irvine11, Yale University12, Icahn School of Medicine at Mount Sinai13, University of Manchester14
TL;DR: Revised algorithms increase comparability between modules and improve the predictive validity of the Autism Diagnostic Observation Schedule for autism cases compared to the original algorithms.
Abstract: Objective: To replicate the factor structure and predictive validity of revised Autism Diagnostic Observation Schedule algorithms in an independent dataset ( N = 1,282). Method: Algorithm revisions were replicated using data from children ages 18 months to 16 years collected at 11 North American sites participating in the Collaborative Programs for Excellence in Autism and the Studies to Advance Autism Research and Treatment. Results: Sensitivities and specificities approximated or exceeded those of the old algorithms except for young children with phrase speech and a clinical diagnosis of pervasive developmental disorders not otherwise specified. Conclusions: Revised algorithms increase comparability between modules and improve the predictive validity of the Autism Diagnostic Observation Schedule forautism cases compared to the original algorithms.
TL;DR: In particular, symbiotic rhizobia appear to advocate for their access to the host by producing a variety of signal molecules capable of suppressing a general pathogen defense response as mentioned in this paper.
Abstract: Rhizobial bacteria colonize legume roots for the purpose of biological nitrogen fixation. A complex series of events, coordinated by host and bacterial signal molecules, underlie the development of this symbiotic interaction. Rhizobia elicit de novo formation of a novel root organ within which they establish a chronic intracellular infection. Legumes permit rhizobia to invade these root tissues while exerting control over the infection process. Once rhizobia gain intracellular access to their host, legumes also strongly influence the process of bacterial differentiation that is required for nitrogen fixation. Even so, symbiotic rhizobia play an active role in promoting their goal of host invasion and chronic persistence by producing a variety of signal molecules that elicit changes in host gene expression. In particular, rhizobia appear to advocate for their access to the host by producing a variety of signal molecules capable of suppressing a general pathogen defense response.
TL;DR: This study demonstrates that community members process information from online communities in a highly contextual manner that may extend to the functionality of the technical tools provided by the online communities.
Abstract: Online communities enable members to exchange messages, and rich content is generated in the wake of these contributions. Little research has systematically investigated how this content is utilized. In this paper we use the HeuristicSystematic Model of information processing to explore the mechanisms by which the potential value of these information assets can be realized. We argue that the extent to which message content and heuristic cues influence the validity assessment process is moderated by two factors: how consistent the new information is with what is already known and the extent to which information-seeking members are actively searching for on-topic information to satisfy their specific information needs. Survey data collected from two online communities generally support the hypotheses derived from this model. This study demonstrates that community members process information from online communities in a highly contextual manner that may extend to the functionality of the technical tools provided by the online communities. It also suggests numerous opportunities for future research and potential ways that online communities might improve their information sharing.
TL;DR: Results suggest the potential utility of teaching self‐harming women more adaptive ways of responding to their emotions, including nonavoidant strategies for modulating emotional arousal and the ability to identify, label, and differentiate among emotional states.
Abstract: Despite the theoretical emphasis on the role of emotion dysregulation in deliberate self‐harm (DSH), few studies have examined this relationship. The present study sought to examine the role of emotion dysregulation in DSH by extending the findings of Gratz (2006) regarding the environmental (i.e. childhood maltreatment) and individual (i.e. emotional inexpressivity and affect intensity/reactivity) factors associated with DSH among 249 female undergraduates. Specifically, the present study examined whether emotion dysregulation (a) is associated with DSH above and beyond these other risk factors and (b) mediates the relationship between these risk factors and DSH. Findings indicate that overall emotion dysregulation distinguished women with frequent DSH from those without a history of DSH, adding reliably to the prediction of DSH status above and beyond maltreatment, inexpressivity, and affect intensity/reactivity. Moreover, among self‐harming women, emotion dysregulation accounted for a significant amoun...
University of Oklahoma1, Potsdam Institute for Climate Impact Research2, Centre national de la recherche scientifique3, University of Colorado Boulder4, Technical University of Denmark5, University of Massachusetts Boston6, Oak Ridge National Laboratory7, Colorado State University8, Swedish University of Agricultural Sciences9, Woods Hole Research Center10, United States Forest Service11
TL;DR: In this article, the effects of climate warming, seasonality, and CO2 levels on seven ecosystems, including forests, grasslands, and heathlands in different climate zones, were investigated.
Abstract: Interactive effects of multiple global change factors on ecosystem processes are complex. It is relatively expensive to explore those interactions in manipulative experiments. We conducted a modeling analysis to identify potentially important interactions and to stimulate hypothesis formulation for experimental research. Four models were used to quantify interactive effects of climate warming (T), altered precipitation amounts [doubled (DP) and halved (HP)] and seasonality (SP, moving precipitation in July and August to January and February to create summer drought), and elevated [CO2 ]( C) on net primary production (NPP), heterotrophic respiration (Rh), net ecosystem production (NEP), transpiration, and runoff. We examined those responses in seven ecosystems, including forests, grasslands, and heathlands in different climate zones. The modeling analysis showed that none of the threeway interactions among T, C, and altered precipitation was substantial for either carbon or water processes, nor consistent among the seven ecosystems. However, two-way interactive effects on NPP, Rh, and NEP were generally positive (i.e. amplification of one factor’s effect by the other factor) between T and C or between T and DP. A negative interaction (i.e. depression of one factor’s effect by the other factor) occurred for simulated NPP between T and HP. The interactive effects on runoff were positive between T and HP. Four pairs of two-way interactive effects on plant transpiration were positive and two pairs negative. In addition, wet sites generally had smaller relative changes in NPP, Rh, runoff, and transpiration but larger absolute changes in NEP than dry sites in response to the treatments. The modeling results suggest new hypotheses to be tested in multifactor global change experiments. Likewise, more experimental evidence is needed for the further improvement of ecosystem models in order to adequately simulate complex interactive processes.
TL;DR: Mentoring is one of the most popular social interventions in American society, with an estimated three million youth in formal one-to-one relationships as mentioned in this paper, and studies have revealed significant associations between youth involvement in mentoring relationships and positive developmental outcomes.
Abstract: Mentoring is one of the most popular social interventions in American society, with an estimated three million youth in formal one-to-one relationships. Studies have revealed significant associations between youth involvement in mentoring relationships and positive developmental outcomes. These associations are modest, however, and depend on several intervening processes. Centrally important is the formation of close, enduring connectionsbetweenmentorsandyouththatfosterpositive developmental change. Effects of mentoring programs likewise typically have been small in magnitude, but they increase systematically with the use of program practices likely to support relationship development. Gaps between research and practice are evident both in the indiscrimi- nate use of the term mentoring in the prevention field and in a focus on the growth and efficiency of mentoring pro- grams at the expense of quality. Continued expansion of effective mentoring will require a better alignment of research and practice.
TL;DR: Total cumulative childhood adversity was related to depressive symptoms, drug use, and antisocial behavior in a positive curvilinear manner with incremental impact increasing as adversities accumulate, but further analysis revealed that this curvilInear effect was an artifact of the confounding of high cumulative adversity scores with the experience of more severe events.
TL;DR: Screening with a standardized tool in early childhood has the potential to identify the majority of children who exhibit significant emotional/behavioral problems in early elementary school.
Abstract: OBJECTIVE. The goal was to examine whether children who screen positive for social-emotional/behavioral problems at 12 to 36 months of age are at elevated risk for social-emotional/behavioral problems in early elementary school. METHODS. The sample studied (N = 1004) comprised an ethnically (33.3% minority) and socioeconomically (17.8% living in poverty and 11.3% living in borderline poverty) diverse, healthy, birth cohort from a metropolitan region of the northeastern United States. When children were 12 to 36 months of age (mean age: 23.8 months; SD: 7.1 months), parents completed the Brief Infant-Toddler Social and Emotional Assessment and questions concerning their level of worry about their child9s behavior, emotions, and social development. When children were in early elementary school (mean age: 6.0 years; SD: 0.4 years), parents completed the Child Behavior Checklist and teachers completed the Teacher Report Form regarding behavioral problems. In a subsample (n = 389), parents reported child psychiatric status. RESULTS. Brief Infant-Toddler Social and Emotional Assessment screen status and parental worry were associated significantly with school-age symptoms and psychiatric disorders. In multivariate analyses that included Brief Infant-Toddler Social and Emotional Assessment status and parental worry, Brief Infant-Toddler Social and Emotional Assessment scores significantly predicted all school-age problems, whereas worry predicted only parent reports with the Child Behavior Checklist. Children with of-concern scores on the problem scale of the Brief Infant-Toddler Social and Emotional Assessment were at increased risk for parent-reported subclinical/clinical levels of problems and for psychiatric disorders. Low competence scores predicted later teacher-reported subclinical/clinical problems and parent-reported disorders. Worry predicted parent-reported subclinical/clinical problems. Moreover, the Brief Infant-Toddler Social and Emotional Assessment identified 49.0% of children who exhibited subclinical/clinical symptoms according to teachers and 67.9% of children who later met the criteria for a psychiatric disorder. CONCLUSIONS. Screening with a standardized tool in early childhood has the potential to identify the majority of children who exhibit significant emotional/behavioral problems in early elementary school.
TL;DR: Although there was evidence of maternal distress in both groups, the presence of significant buffering effects reflects adaptation in the face of stress, particularly for mothers of adolescents.
Abstract: The present study examined the impact of autism symptoms and coping strategies on the well-being of mothers of children with autism spectrum disorder (ASD). The sample consisted of 153 mothers of toddlers and 201 mothers of adolescents drawn from two ongoing, longitudinal studies of families of individuals with ASD. For mothers of toddlers, lower levels of emotion-focused coping and higher levels of problem-focused coping were generally associated with better maternal well-being, regardless of the level of child symptomatology. For mothers of adolescents, coping often acted as a buffer when autism symptoms were high. Although there was evidence of maternal distress in both groups, the presence of significant buffering effects reflects adaptation in the face of stress, particularly for mothers of adolescents.
TL;DR: In this paper, the authors used a gridded, global-scale water balance model to estimate interannual variability in global irrigation water demand arising from climate data sets and uncertainties arising from agricultural and climate data.
Abstract: [1] Agricultural water use accounts for around 70% of the total water that is withdrawn from surface water and groundwater. We use a new, gridded, global-scale water balance model to estimate interannual variability in global irrigation water demand arising from climate data sets and uncertainties arising from agricultural and climate data sets. We used contemporary maps of irrigation and crop distribution, and so do not account for variability or trends in irrigation area or cropping. We used two different global maps of irrigation and two different reconstructions of daily weather 1963–2002. Simulated global irrigation water demand varied by ∼30%, depending on irrigation map or weather data. The combined effect of irrigation map and weather data generated a global irrigation water use range of 2200 to 3800 km3 a−1. Weather driven variability in global irrigation was generally less than ±300 km3 a−1, globally (<∼10%), but could be as large as ±70% at the national scale.
01 Jan 2008
TL;DR: In this paper, the authors proposed a solar concentrator pathway to low-cost Electrolytic Hydrogen and Thermochemical and Thermal/Photo Hybrid Solar Water Splitting for renewable energy and the Hydrogen economy.
Abstract: Renewable Energy and the Hydrogen Economy.- The Solar Resource.- Electrolysis of Water.- A Solar Concentrator Pathway to Low-Cost Electrolytic Hydrogen.- Thermochemical and Thermal/Photo Hybrid Solar Water Splitting.- Molecular Approaches to Photochemical Splitting of Water.- Hydrogen Generation from Irradiated Semiconductor-Liquid Interfaces.- Photobiological Methods of Renewable Hydrogen Production.- Centralized Production of Hydrogen using a Coupled Water Electrolyzer-Solar Photovoltaic System.
TL;DR: Results demonstrated that suppression produced short-term reductions in sadness, and found that suppression was no longer effective at moderate and higher levels of anxiety about the experience of depressed mood.
TL;DR: It is shown that Rabaptin5 binds to both Elipsa and Rab8, suggesting that these proteins provide a bridging mechanism between the IFT particle and protein complexes that assemble at the ciliary membrane.
Abstract: The formation and function of cilia involves the movement of intraflagellar transport (IFT) particles underneath the ciliary membrane, along axonemal microtubules. Although this process has been studied extensively, its molecular basis remains incompletely understood. For example, it is unknown how the IFT particle interacts with transmembrane proteins. To study the IFT particle further, we examined elipsa, a locus characterized by mutations that cause particularly early ciliogenesis defects in zebrafish. We show here that elipsa encodes a coiled-coil polypeptide that localizes to cilia. Elipsa protein binds to Ift20, a component of IFT particles, and Elipsa homologue in Caenorhabditis elegans, DYF-11, translocates in sensory cilia, similarly to the IFT particle. This indicates that Elipsa is an IFT particle polypeptide. In the context of zebrafish embryogenesis, Elipsa interacts genetically with Rabaptin5, a well-studied regulator of endocytosis, which in turn interacts with Rab8, a small GTPase, known to localize to cilia. We show that Rabaptin5 binds to both Elipsa and Rab8, suggesting that these proteins provide a bridging mechanism between the IFT particle and protein complexes that assemble at the ciliary membrane.
TL;DR: This work considers the problem of estimating the geographic locations of nodes in a wireless sensor network where most sensors are without an effective self-positioning functionality and proposes LSVM, a novel solution based on Support Vector Machine learning that addresses the border and coverage-hole problems effectively.
Abstract: We consider the problem of estimating the geographic locations of nodes in a wireless sensor network where most sensors are without an effective self-positioning functionality. We propose LSVM-a novel solution with the following merits. First, LSVM localizes the network based on mere connectivity information (that is, hop counts only) and therefore is simple and does not require specialized ranging hardware or assisting mobile devices as in most existing techniques. Second, LSVM is based on Support Vector Machine (SVM) learning. Although SVM is a classification method, we show its applicability to the localization problem and prove that the localization error can be upper bounded by any small threshold given an appropriate training data size. Third, LSVM addresses the border and coverage-hole problems effectively. Last but not least, LSVM offers fast localization in a distributed manner with efficient use of processing and communication resources. We also propose a modified version of mass-spring optimization to further improve the location estimation in LSVM. The promising performance of LSVM is exhibited by our simulation study.
15 Apr 2008
TL;DR: A conceptual model of police response to persons with mental illness is presented that accounts for officer, organizational, mental health system and community level factors likely to influence implementation and effectiveness of CIT and other approaches.
TL;DR: The authors used structural equation modeling techniques and a nationally representative sample to understand racial differences in the direct and indirect effects of campus racial climate on degree completion and found that students from disparate racial backgrounds may experience and react to their campus racial climates in different ways.
Abstract: Racial minority student persistence is of paramount importance to higher education policymakers and practitioners. This study was aimed at understanding racial differences in the direct and indirect effects of campus racial climate on degree completion using structural equation modeling techniques and a nationally representative sample. The findings of this analysis highlight the importance of examining conditional effects and indicate that students from disparate racial backgrounds may experience and react to their campus racial climates in different ways. Implications for research and practice are discussed.
TL;DR: Exploratory results support an inverse association between audiovisual speech processing capacities and social impairment in children with ASD and suggest thatChildren with ASD may use visual information for speech differently from children without ASD.
Abstract: Fifteen children with autism spectrum disorders (ASD) and twenty-one children without ASD completed six perceptual tasks designed to characterize the nature of the audiovisual processing difficulties experienced by children with ASD. Children with ASD scored significantly lower than children without ASD on audiovisual tasks involving human faces and voices, but scored similarly to children without ASD on audiovisual tasks involving nonhuman stimuli (bouncing balls). Results suggest that children with ASD may use visual information for speech differently from children without ASD. Exploratory results support an inverse association between audiovisual speech processing capacities and social impairment in children with ASD.
TL;DR: Poor specificity of symptoms and academic complaints casts doubt on the utility of this self-reported information in diagnosis, particularly if used alone and without regard to severity or extent of impairment.
Abstract: Objective: Previous research has found ADHD symptoms to be common in the general population but has not compared endorsement of symptoms between ADHD and non-ADHD groups. This study examines self-r...
Potsdam Institute for Climate Impact Research1, University of Oklahoma2, Centre national de la recherche scientifique3, University of Colorado Boulder4, University of Massachusetts Boston5, Oak Ridge National Laboratory6, Colorado State University7, Swedish University of Agricultural Sciences8, Woods Hole Research Center9, United States Forest Service10
TL;DR: In this article, the authors explored the effects of potential P changes on water limitation and net primary production in seven terrestrial ecosystems with distinctive vegetation types in different hydroclimatic zones and found that NPP responses to P changes differed not only among sites but also within a year at a given site.
Abstract: The ongoing changes in the global climate expose the world’s ecosystems not only to increasing CO2 concentrations and temperatures but also to altered precipitation (P) regimes. Using four well-established process-based ecosystem models (LPJ, DayCent, ORCHIDEE, TECO), we explored effects of potential P changes on water limitation and net primary production (NPP) in seven terrestrial ecosystems with distinctive vegetation types in different hydroclimatic zones. We found that NPP responses to P changes differed not only among sites but also within a year at a given site. The magnitudes of NPP change were basically determined by the degree of ecosystem water limitation, which was quantified here using the ratio between atmospheric transpirational demand and soil water supply. Humid sites and/or periods were least responsive to any change in P as compared with moderately humid or dry sites/periods. We also found that NPP responded more strongly to doubling or halving of P amount and a seasonal shift in P occurrence than that to altered P frequency and intensity at constant annual amounts. The findings were highly robust across the four models especially in terms of the direction of changes and largely consistent with earlier P manipulation experiments and modelling results. Overall, this study underscores the widespread importance of P as a driver of change in ecosystems, although the ultimate response of a particular site will depend on the detailed nature and seasonal timing of P change.