Showing papers by "University of California, Davis published in 2006"
Dalhousie University1, University of Wyoming2, Plymouth Marine Laboratory3, Stockholm University4, Royal Swedish Academy of Sciences5, University of California, Santa Barbara6, Scripps Institution of Oceanography7, Smithsonian Tropical Research Institute8, Stanford University9, University of California, Davis10, University of British Columbia11
TL;DR: The authors analyzed local experiments, long-term regional time series, and global fisheries data to test how biodiversity loss affects marine ecosystem services across temporal and spatial scales, concluding that marine biodiversity loss is increasingly impairing the ocean's capacity to provide food, maintain water quality, and recover from perturbations.
Abstract: Human-dominated marine ecosystems are experiencing accelerating loss of populations and species, with largely unknown consequences. We analyzed local experiments, long-term regional time series, and global fisheries data to test how biodiversity loss affects marine ecosystem services across temporal and spatial scales. Overall, rates of resource collapse increased and recovery potential, stability, and water quality decreased exponentially with declining diversity. Restoration of biodiversity, in contrast, increased productivity fourfold and decreased variability by 21%, on average. We conclude that marine biodiversity loss is increasingly impairing the ocean's capacity to provide food, maintain water quality, and recover from perturbations. Yet available data suggest that at this point, these trends are still reversible.
3,672 citations
TL;DR: In this paper, the authors test and confirm the hypothesis that individual investors are net buyers of attentiongrabbing stocks, e.g., stocks in the news, stocks experiencing high abnormal trading volume, and stocks with extreme one day returns.
Abstract: We test and confirm the hypothesis that individual investors are net buyers of attention-grabbing stocks, e.g., stocks in the news, stocks experiencing high abnormal trading volume, and stocks with extreme one day returns. Attention-driven buying results from the difficulty that investors have searching the thousands of stocks they can potentially buy. Individual investors don't face the same search problem when selling because they tend to sell only stocks they already own. We hypothesize that many investors only consider purchasing stocks that have first caught their attention. Thus, preferences determine choices after attention has determined the choice set.
3,048 citations
TL;DR: In this article, the authors proposed a targeted global conservation effort that includes a reduction of watershed nutrient and sediment inputs to seagrass habitats and a targeted educational program informing regulators and the public of the value of meadows.
Abstract: Seagrasses, marine flowering plants, have a long evolutionary history but are now challenged with rapid environmental changes as a result of coastal human population pressures. Seagrasses provide key ecological services, including organic carbon production and export, nutrient cycling, sediment stabilization, enhanced biodiversity, and trophic transfers to adjacent habitats in tropical and temperate regions. They also serve as “coastal canaries,” global biological sentinels of increasing anthropogenic influences in coastal ecosystems, with large-scale losses reported worldwide. Multiple stressors, including sediment and nutrient runoff, physical disturbance, invasive species, disease, commercial fishing practices, aquaculture, overgrazing, algal blooms, and global warming, cause seagrass declines at scales of square meters to hundreds of square kilometers. Reported seagrass losses have led to increased awareness of the need for seagrass protection, monitoring, management, and restoration. However, seagrass science, which has rapidly grown, is disconnected from public awareness of seagrasses, which has lagged behind awareness of other coastal ecosystems. There is a critical need for a targeted global conservation effort that includes a reduction of watershed nutrient and sediment inputs to seagrass habitats and a targeted educational program informing regulators and the public of the value of seagrass meadows.
2,645 citations
TL;DR: The relationship between temperature and individual performance is reasonably well understood, and much climate-related research has focused on potential shifts in distribution and abundance driven directly by temperature as discussed by the authors, however, recent work has revealed that both abiotic changes and biological responses in the ocean will be substantially more complex.
Abstract: Anthropogenically induced global climate change has profound implications for marine ecosystems and the economic and social systems that depend upon them. The relationship between temperature and individual performance is reasonably well understood, and much climate-related research has focused on potential shifts in distribution and abundance driven directly by temperature. However, recent work has revealed that both abiotic changes and biological responses in the ocean will be substantially more complex. For example, changes in ocean chemistry may be more important than changes in temperature for the performance and survival of many organisms. Ocean circulation, which drives larval transport, will also change, with important consequences for population dynamics. Furthermore, climatic impacts on one or a few 'leverage species' may result in sweeping community-level changes. Finally, synergistic effects between climate and other anthropogenic variables, particularly fishing pressure, will likely exacerbate climate-induced changes. Efforts to manage and conserve living marine systems in the face of climate change will require improvements to the existing predictive framework. Key directions for future research include identifying key demographic transitions that influence population dynamics, predicting changes in the community-level impacts of ecologically dominant species, incorporating populations' ability to evolve (adapt), and understanding the scales over which climate will change and living systems will respond.
2,137 citations
TL;DR: Kepler as mentioned in this paper is a scientific workflow system, which is currently under development across a number of scientific data management projects and is a community-driven, open source project, and always welcome related projects and new contributors to join.
Abstract: Many scientific disciplines are now data and information driven, and new scientific knowledge is often gained by scientists putting together data analysis and knowledge discovery “pipelines”. A related trend is that more and more scientific communities realize the benefits of sharing their data and computational services, and are thus contributing to a distributed data and computational community infrastructure (a.k.a. “the Grid”). However, this infrastructure is only a means to an end and scientists ideally should be bothered little with its existence. The goal is for scientists to focus on development and use of what we call scientific workflows. These are networks of analytical steps that may involve, e.g., database access and querying steps, data analysis and mining steps, and many other steps including computationally intensive jobs on high performance cluster computers. In this paper we describe characteristics of and requirements for scientific workflows as identified in a number of our application projects. We then elaborate on Kepler, a particular scientific workflow system, currently under development across a number of scientific data management projects. We describe some key features of Kepler and its underlying Ptolemyii system, planned extensions, and areas of future research. Kepler is a communitydriven, open source project, and we always welcome related projects and new contributors to join.
1,926 citations
TL;DR: In this article, a review of the basic ideas and techniques of spectral density functional theory which are currently used in electronic structure calculations of strongly correlated materials where the one-dimensional electron description breaks down is presented.
Abstract: We present a review of the basic ideas and techniques of the spectral density functional theory which are currently used in electronic structure calculations of strongly{correlated materials where the one{electron description breaks down. We illustrate the method with several examples where interactions play a dominant role: systems near metal{insulator transition, systems near volume collapse transition, and systems with local moments.
1,921 citations
TL;DR: In this article, the use of electric current to activate the consolidation and reaction-sintering of materials is reviewed with special emphasis of the spark plasma sintering method, which has been used extensively over the past decade with results showing clear benefits over conventional methods.
Abstract: The use of electric current to activate the consolidation and reaction-sintering of materials is reviewed with special emphasis of the spark plasma sintering method. The method has been used extensively over the past decade with results showing clear benefits over conventional methods. The review critically examines the important features of this method and their individual roles in the observed enhancement of the consolidation process and the properties of the resulting materials.
1,855 citations
Ohio State University1, Fred Hutchinson Cancer Research Center2, University of Cincinnati3, University of Iowa4, University of California, Davis5, University of Alabama at Birmingham6, University of Arizona7, University of Washington8, Rush University Medical Center9, Wake Forest University10, University of Nevada, Reno11, University of Texas at San Antonio12, Kaiser Permanente13, University of Pittsburgh14, University of California, Los Angeles15, Stony Brook University16, Baylor College of Medicine17, University of North Carolina at Chapel Hill18, Wayne State University19, Howard University20, George Washington University21, University of California, Irvine22, University of Tennessee Health Science Center23, Medical College of Wisconsin24, University of California, San Diego25, Rutgers University26, University of Florida27, National Institutes of Health28, Harvard University29, University of Minnesota30, University of Massachusetts Boston31, University of Miami32, Emory University33, University of Wisconsin-Madison34, Stanford University35, Northwestern University36, University at Buffalo37, Brown University38, Yeshiva University39
TL;DR: Among healthy postmenopausal women, calcium with vitamin D supplementation resulted in a small but significant improvement in hip bone density, did not significantly reduce hip fracture, and increased the risk of kidney stones.
Abstract: Background The efficacy of calcium with vitamin D supplementation for preventing hip and other fractures in healthy postmenopausal women remains equivocal. Methods We recruited 36,282 postmenopausal women, 50 to 79 years of age, who were already enrolled in a Women's Health Initiative (WHI) clinical trial. We randomly assigned participants to receive 1000 mg of elemental calcium as calcium carbonate with 400 IU of vitamin D3 daily or placebo. Fractures were ascertained for an average follow-up period of 7.0 years. Bone density was measured at three WHI centers. Results Hip bone density was 1.06 percent higher in the calcium plus vitamin D group than in the placebo group (P<0.01). Intention-to-treat analysis indicated that participants receiving calcium plus vitamin D supplementation had a hazard ratio of 0.88 for hip fracture (95 percent confidence interval, 0.72 to 1.08), 0.90 for clinical spine fracture (0.74 to 1.10), and 0.96 for total fractures (0.91 to 1.02). The risk of renal calculi increased with...
1,765 citations
TL;DR: Using TRPA1-deficient mice, it is shown that this channel is the sole target through which mustard oil and garlic activate primary afferent nociceptors to produce inflammatory pain.
1,748 citations
TL;DR: In this paper, the current knowledge of microbial processes affecting C sequestration in agroecosystems is reviewed, and gaps within our knowledge on MOM-C dynamics and how they are related to soil properties and agricultural practices are identified.
Abstract: This paper reviews the current knowledge of microbial processes affecting C sequestration in agroecosystems. The microbial contribution to soil C storage is directly related to microbial community dynamics and the balance between formation and degradation of microbial byproducts. Soil microbes also indirectly influence C cycling by improving soil aggregation, which physically protects soil organic matter (SOM). Consequently, the microbial contribution to C sequestration is governed by the interactions between the amount of microbial biomass, microbial community structure, microbial byproducts, and soil properties such as texture, clay mineralogy, pore-size distribution, and aggregate dynamics. The capacity of a soil to protect microbial biomass and microbially derived organic matter (MOM) is directly and/or indirectly (i.e., through physical protection by aggregates) related to the reactive properties of clays. However, the stabilization of MOM in the soil is also related to the efficiency with which microorganisms utilize substrate C and the chemical nature of the byproducts they produce. Crop rotations, reduced or no-tillage practices, organic farming, and cover crops increase total microbial biomass and shift the community structure toward a more fungal-dominated community, thereby enhancing the accumulation of MOM. A quantitative and qualitative improvement of SOM is generally observed in agroecosystems favoring a fungal-dominated community, but the mechanisms leading to this improvement are not completely understood. Gaps within our knowledge on MOM-C dynamics and how they are related to soil properties and agricultural practices are identified.
1,576 citations
TL;DR: The Kiddie Schedule for Affective Disorders and Schizophrenia was modified for use in children and adolescents with autism by developing additional screening questions and coding options that reflect the presentation of psychiatric disorders in autism spectrum disorders.
Abstract: The Kiddie Schedule for Affective Disorders and Schizophrenia was modified for use in children and adolescents with autism by developing additional screening questions and coding options that reflect the presentation of psychiatric disorders in autism spectrum disorders. The modified instrument, the Autism Comorbidity Interview-Present and Lifetime Version (ACI-PL), was piloted and frequently diagnosed disorders, depression, ADHD, and OCD, were tested for reliability and validity. The ACI-PL provides reliable DSM diagnoses that are valid based on clinical psychiatric diagnosis and treatment history. The sample demonstrated a high prevalence of specific phobia, obsessive compulsive disorder, and ADHD. The rates of psychiatric disorder in autism are high and are associated with functional impairment.
University of Western Ontario1, Cornell University2, Mayo Clinic3, Erasmus University Rotterdam4, University of Illinois at Chicago5, University of Toronto6, Washington University in St. Louis7, University of California, Davis8, National Institutes of Health9, Newcastle upon Tyne Hospitals NHS Foundation Trust10, University of California, Los Angeles11, University of New Mexico12, Ludwig Maximilian University of Munich13
TL;DR: Using the same standards will help identify individuals in the early stages of cognitive impairment, will make studies comparable, and by integrating knowledge, will accelerate the pace of progress.
Abstract: Background and Purpose—One in 3 individuals will experience a stroke, dementia or both. Moreover, twice as many individuals will have cognitive impairment short of dementia as either stroke or dementia. The commonly used stroke scales do not measure cognition, while dementia criteria focus on the late stages of cognitive impairment, and are heavily biased toward the diagnosis of Alzheimer disease. No commonly agreed standards exist for identifying and describing individuals with cognitive impairment, particularly in the early stages, and especially with cognitive impairment related to vascular factors, or vascular cognitive impairment. Methods—The National Institute for Neurological Disorders and Stroke (NINDS) and the Canadian Stroke Network (CSN) convened researchers in clinical diagnosis, epidemiology, neuropsychology, brain imaging, neuropathology, experimental models, biomarkers, genetics, and clinical trials to recommend minimum, common, clinical and research standards for the description and study of vascular cognitive impairment. Results—The results of these discussions are reported herein. Conclusions—The development of common standards represents a first step in a process of use, validation and refinement. Using the same standards will help identify individuals in the early stages of cognitive impairment, will make studies comparable, and by integrating knowledge, will accelerate the pace of progress. (Stroke. 2006;37:2220-2241.)
TL;DR: The authors studied the evolution of the ionization state of the intergalactic medium (IGM) at the end of the reionization epoch using moderate-resolution spectra of a sample of 19 quasars at 5.74 5.7.
Abstract: We study the evolution of the ionization state of the intergalactic medium (IGM) at the end of the reionization epoch using moderate-resolution spectra of a sample of 19 quasars at 5.74 5.7: the GP optical depth evolution changes from τ ~ (1 + z)4.3 to (1 + z)11, and the average length of dark gaps with τ > 3.5 increases from 80 comoving Mpc. The dispersion of IGM properties along different lines of sight also increases rapidly, implying fluctuations by a factor of 4 in the UV background at z > 6, when the mean free path of UV photons is comparable to the correlation length of the star-forming galaxies that are thought to have caused reionization. The mean length of dark gaps shows the most dramatic increase at z ~ 6, as well as the largest line-of-sight variations. We suggest using dark gap statistics as a powerful probe of the ionization state of the IGM at yet higher redshift. The sizes of H II regions around luminous quasars decrease rapidly toward higher redshift, suggesting that the neutral fraction of the IGM has increased by a factor of 10 from z = 5.7 to 6.4, consistent with the value derived from the GP optical depth. The mass-averaged neutral fraction is 1%-4% at z ~ 6.2 based on the GP optical depth and H II region size measurements. The observations suggest that z ~ 6 is the end of the overlapping stage of reionization and are inconsistent with a mostly neutral IGM at z ~ 6, as indicated by the finite length of the dark absorption gaps.
TL;DR: The positional cloning of Gpc-B1, a wheat quantitative trait locus associated with increased grain protein, zinc, and iron content, is reported here, and reduction in RNA levels of the multiple NAM homologs by RNA interference delayed senescence by more than 3 weeks and reduced wheat grain protein and zinc content.
Abstract: Enhancing the nutritional value of food crops is a means of improving human nutrition and health. We report here the positional cloning of Gpc-B1, a wheat quantitative trait locus associated with increased grain protein, zinc, and iron content. The ancestral wild wheat allele encodes a NAC transcription factor (NAM-B1) that accelerates senescence and increases nutrient remobilization from leaves to developing grains, whereas modern wheat varieties carry a nonfunctional NAM-B1 allele. Reduction in RNA levels of the multiple NAM homologs by RNA interference delayed senescence by more than 3 weeks and reduced wheat grain protein, zinc, and iron content by more than 30%.
TL;DR: The identification of a cluster of three genes at the Sub1 locus, encoding putative ethylene response factors, indicates that Sub1A-1 is a primary determinant of submergence tolerance in O. sativa ssp.
Abstract: Most Oryza sativa cultivars die within a week of complete submergence--a major constraint to rice production in south and southeast Asia that causes annual losses of over US 1 billion dollars and affects disproportionately the poorest farmers in the world. A few cultivars, such as the O. sativa ssp. indica cultivar FR13A, are highly tolerant and survive up to two weeks of complete submergence owing to a major quantitative trait locus designated Submergence 1 (Sub1) near the centromere of chromosome 9 (refs 3, 4, 5-6). Here we describe the identification of a cluster of three genes at the Sub1 locus, encoding putative ethylene response factors. Two of these genes, Sub1B and Sub1C, are invariably present in the Sub1 region of all rice accessions analysed. In contrast, the presence of Sub1A is variable. A survey identified two alleles within those indica varieties that possess this gene: a tolerance-specific allele named Sub1A-1 and an intolerance-specific allele named Sub1A-2. Overexpression of Sub1A-1 in a submergence-intolerant O. sativa ssp. japonica conferred enhanced tolerance to the plants, downregulation of Sub1C and upregulation of Alcohol dehydrogenase 1 (Adh1), indicating that Sub1A-1 is a primary determinant of submergence tolerance. The FR13A Sub1 locus was introgressed into a widely grown Asian rice cultivar using marker-assisted selection. The new variety maintains the high yield and other agronomic properties of the recurrent parent and is tolerant to submergence. Cultivation of this variety is expected to provide protection against damaging floods and increase crop security for farmers.
Emory University1, University of California, Davis2, University of Oxford3, California Institute of Technology4, University of California, Los Angeles5, College of DuPage6, University of Los Andes7, University of California, Santa Barbara8, Guilford College9, Washington University in St. Louis10, Harvard University11, University of Colorado Denver12, Boise State University13
TL;DR: Experimental results from 15 diverse populations show that all populations demonstrate some willingness to administer costly punishment as unequal behavior increases, and the magnitude of this punishment varies substantially across populations, and costly punishment positively covaries with altruistic behavior across populations.
Abstract: Recent behavioral experiments aimed at understanding the evolutionary foundations of human cooperation have suggested that a willingness to engage in costly punishment, even in one-shot situations, may be part of human psychology and a key element in understanding our sociality. However, because most experiments have been confined to students in industrialized societies, generalizations of these insights to the species have necessarily been tentative. Here, experimental results from 15 diverse populations show that (i) all populations demonstrate some willingness to administer costly punishment as unequal behavior increases, (ii) the magnitude of this punishment varies substantially across populations, and (iii) costly punishment positively covaries with altruistic behavior across populations. These findings are consistent with models of the gene-culture coevolution of human altruism and further sharpen what any theory of human cooperation needs to explain.
National Institutes of Health1, Birkbeck, University of London2, United States Department of Energy3, North Carolina State University4, United States Department of Agriculture5, Utah State University6, University of Nebraska–Lincoln7, University of Minnesota8, University of Wisconsin-Madison9, University of California, San Diego10, University of California, Davis11, University of Idaho12
TL;DR: Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.
Abstract: Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.
TL;DR: Hahn et al. as mentioned in this paper presented CAFE (Computational Analysis of gene Family Evolution), a tool for the statistical analysis of the evolution of the size of gene families.
Abstract: Summary: We present CAFE (Computational Analysis of gene Family Evolution), a tool for the statistical analysis of the evolution of the size of gene families. It uses a stochastic birth and death process to model the evolution of gene family sizes over a phylogeny. For a specified phylogenetic tree, and given the gene family sizes in the extant species, CAFE can estimate the global birth and death rate of gene families, infer the most likely gene family size at all internal nodes, identify gene families that have accelerated rates of gain and loss (quantified by a p-value) and identify which branches cause the p-value to be small for significant families.
Availability: Software is available from http://www.bio.indiana.edu/~hahnlab/Software.html
Contact: mwh@indiana.edu
TL;DR: In this article, the results of a study in which natural microbial biological processes were used to engineer a cemented soil matrix within initially loose, collapsible sand were presented, using the microorganism Bacillus pasteurii, an aerobic bacterium pervasive in natural soil deposits.
Abstract: Current methods to improve the engineering properties of sands are diverse with respect to methodology, treatment uniformity, cost, environmental impact, site accessibility requirements, etc. All of these methods have benefits and drawbacks, and there continues to be a need to explore new possibilities of soil improvement, particularly as suitable land for development becomes more scarce. This paper presents the results of a study in which natural microbial biological processes were used to engineer a cemented soil matrix within initially loose, collapsible sand. Microbially induced calcite precipitation (MICP) was achieved using the microorganism Bacillus pasteurii, an aerobic bacterium pervasive in natural soil deposits. The microbes were introduced to the sand specimens in a liquid growth medium amended with urea and a dissolved calcium source. Subsequent cementation treatments were passed through the specimen to increase the cementation level of the sand particle matrix. The results of both MICP- and ...
TL;DR: For some types of cancer, the incidence of venous thromboembolism was sufficiently high to warrant prospective clinical trials of primary thromboprophylaxis and was highest among patients initially diagnosed with metastatic-stage disease.
Abstract: Background: The incidence of venous thromboembolism after diagnosis of specific cancers and the effect of thromboembolism on survival are not well defined. Methods: The California Cancer Registry was linked to the California Patient Discharge Data Set to determine the incidence of venous thromboembolism among cancer cases diagnosed between 1993 and 1995. The incidence and timing of thromboembolism within 1 and 2 years of cancer diagnosis and the risk factors associated with thromboembolism and death were determined. Results: Among 235 149 cancer cases, 3775 (1.6%) were diagnosed with venous thromboembolism within 2 years, 463 (12%) at the time cancer was diagnosed and 3312 (88%) subsequently. In risk-adjusted models, metastatic disease at the time of diagnosis was the strongest predictor of thromboembolism. Expressed as events per 100 patient-years, the highest incidence of thromboembolism occurred during the first year of follow-up among cases with metastatic-stage pancreatic (20.0), stomach (10.7), bladder (7.9), uterine (6.4), renal (6.0), and lung (5.0) cancer. Adjusting for age, race, and stage, diagnosis of thromboembolism was a significant predictor of decreased survival during the first year for all cancer types (hazard ratios, 1.6-4.2; P Conclusions: The incidence of venous thromboembolism varied with cancer type and was highest among patients initially diagnosed with metastatic-stage disease. The incidence rate of thromboembolism decreased over time. Diagnosis of thromboembolism during the first year of follow-up was a significant predictor of death for most cancer types and stages analyzed. For some types of cancer, the incidence of thromboembolism was sufficiently high to warrant prospective clinical trials of primary thromboprophylaxis.
TL;DR: It is found that although there are important potential trade-offs between conservation for biodiversity and for ecosystem services, a systematic planning framework offers scope for identifying valuable synergies.
Abstract: Despite increasing attention to the human dimension of conservation projects, a rigorous, systematic methodology for planning for ecosystem services has not been developed. This is in part because flows of ecosystem services remain poorly characterized at local-to-regional scales, and their protection has not generally been made a priority. We used a spatially explicit conservation planning framework to explore the trade-offs and opportunities for aligning conservation goals for biodiversity with six ecosystem services (carbon storage, flood control, forage production, outdoor recreation, crop pollination, and water provision) in the Central Coast ecoregion of California, United States. We found weak positive and some weak negative associations between the priority areas for biodiversity conservation and the flows of the six ecosystem services across the ecoregion. Excluding the two agriculture-focused services—crop pollination and forage production—eliminates all negative correlations. We compared the degree to which four contrasting conservation network designs protect biodiversity and the flow of the six services. We found that biodiversity conservation protects substantial collateral flows of services. Targeting ecosystem services directly can meet the multiple ecosystem services and biodiversity goals more efficiently but cannot substitute for targeted biodiversity protection (biodiversity losses of 44% relative to targeting biodiversity alone). Strategically targeting only biodiversity plus the four positively associated services offers much promise (relative biodiversity losses of 7%). Here we present an initial analytical framework for integrating biodiversity and ecosystem services in conservation planning and illustrate its application. We found that although there are important potential trade-offs between conservation for biodiversity and for ecosystem services, a systematic planning framework offers scope for identifying valuable synergies.
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TL;DR: This paper showed that immigrants are imperfect substitutes for U.S.-born workers within the same education-experience-gender group (because they choose different occupations and have different skills) and that most of the wage effects of immigration accrue to native workers within a decade.
Abstract: This paper asks the following question: what was the effect of surging immigration on average and individual wages of U.S.-born workers during the period 1990-2004? We emphasize the need for a general equilibrium approach to analyze this problem. The impact of immigrants on wages of U.S.-born workers can be evaluated only by accounting carefully for labor market and capital market interactions in production. Using such a general equilibrium approach we estimate that immigrants are imperfect substitutes for U.S.- born workers within the same education-experience-gender group (because they choose different occupations and have different skills). Moreover, accounting for a reasonable speed of adjustment of physical capital we show that most of the wage effects of immigration accrue to native workers within a decade. These two facts imply a positive and significant effect of the 1990-2004 immigration on the average wage of U.S.-born workers overall, both in the short run and in the long run. This positive effect results from averaging a positive effect on wages of U.S.-born workers with at least a high school degree and a small negative effect on wages of U.S.-born workers with no high school degree.
TL;DR: The origins of momentary creative moments are investigated, and a model of collective creativity is built that identifies the precipitating roles played by four types of social interaction: help seeking, help giving, reflective reframing, and reinforcing.
Abstract: This paper introduces a model of collective creativity that explains how the locus of creative problem solving shifts, at times, from the individual to the interactions of a collective. The model is grounded in observations, interviews, informal conversations, and archival data gathered in intensive field studies of work in professional service firms. The evidence suggests that although some creative solutions can be seen as the products of individual insight, others should be regarded as the products of a momentary collective process. Such collective creativity reflects a qualitative shift in the nature of the creative process, as the comprehension of a problematic situation and the generation of creative solutions draw from---and reframe---the past experiences of participants in ways that lead to new and valuable insights. This research investigates the origins of such moments, and builds a model of collective creativity that identifies the precipitating roles played by four types of social interaction: help seeking, help giving, reflective reframing, and reinforcing. Implications of this research include shifting the emphasis in research and management of creativity from identifying and managing creative individuals to understanding the social context and developing interactive approaches to creativity, and from a focus on relatively constant contextual variables to the alignment of fluctuating variables and their precipitation of momentary phenomena.
Howard University1, Memorial Hospital of South Bend2, Northwestern University3, George Washington University4, Harvard University5, Stanford University6, Yeshiva University7, University of Pittsburgh8, Fred Hutchinson Cancer Research Center9, University of California, San Diego10, Rutgers University11, University of Alabama at Birmingham12, University of Florida13, University of Minnesota14, Ohio State University15, University of Massachusetts Medical School16, University of Miami17, Emory University18, University of California, Davis19, National Institutes of Health20, University of Wisconsin-Madison21, University of Iowa22, Kaiser Permanente23, University at Buffalo24, Wake Forest University25, Pfizer26, Brown University27, University of Arizona28, Rush University Medical Center29, University of Nevada, Reno30, University of Texas at San Antonio31, University of California, Los Angeles32, University of Cincinnati33, Stony Brook University34, Baylor College of Medicine35, University of North Carolina at Chapel Hill36, Wayne State University37, University of California, Irvine38, University of Tennessee Health Science Center39, Medical College of Wisconsin40
TL;DR: A dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women and achieved only modest effects on CVD risk factors, suggesting that more focused diet and lifestyle interventions may be needed to improve risk factors and reduce CVDrisk.
Abstract: ContextMultiple epidemiologic studies and some trials have linked diet with cardiovascular disease (CVD) prevention, but long-term intervention data are needed.ObjectiveTo test the hypothesis that a dietary intervention, intended to be low in fat and high in vegetables, fruits, and grains to reduce cancer, would reduce CVD risk.Design, Setting, and ParticipantsRandomized controlled trial of 48 835 postmenopausal women aged 50 to 79 years, of diverse backgrounds and ethnicities, who participated in the Women's Health Initiative Dietary Modification Trial. Women were randomly assigned to an intervention (19 541 [40%]) or comparison group (29 294 [60%]) in a free-living setting. Study enrollment occurred between 1993 and 1998 in 40 US clinical centers; mean follow-up in this analysis was 8.1 years.InterventionIntensive behavior modification in group and individual sessions designed to reduce total fat intake to 20% of calories and increase intakes of vegetables/fruits to 5 servings/d and grains to at least 6 servings/d. The comparison group received diet-related education materials.Main Outcome MeasuresFatal and nonfatal coronary heart disease (CHD), fatal and nonfatal stroke, and CVD (composite of CHD and stroke).ResultsBy year 6, mean fat intake decreased by 8.2% of energy intake in the intervention vs the comparison group, with small decreases in saturated (2.9%), monounsaturated (3.3%), and polyunsaturated (1.5%) fat; increases occurred in intakes of vegetables/fruits (1.1 servings/d) and grains (0.5 serving/d). Low-density lipoprotein cholesterol levels, diastolic blood pressure, and factor VIIc levels were significantly reduced by 3.55 mg/dL, 0.31 mm Hg, and 4.29%, respectively; levels of high-density lipoprotein cholesterol, triglycerides, glucose, and insulin did not significantly differ in the intervention vs comparison groups. The numbers who developed CHD, stroke, and CVD (annualized incidence rates) were 1000 (0.63%), 434 (0.28%), and 1357 (0.86%) in the intervention and 1549 (0.65%), 642 (0.27%), and 2088 (0.88%) in the comparison group. The diet had no significant effects on incidence of CHD (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.90-1.06), stroke (HR, 1.02; 95% CI, 0.90-1.15), or CVD (HR, 0.98; 95% CI, 0.92-1.05). Excluding participants with baseline CVD (3.4%), the HRs (95% CIs) for CHD and stroke were 0.94 (0.86-1.02) and 1.02 (0.90-1.17), respectively. Trends toward greater reductions in CHD risk were observed in those with lower intakes of saturated fat or trans fat or higher intakes of vegetables/fruits.ConclusionsOver a mean of 8.1 years, a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women and achieved only modest effects on CVD risk factors, suggesting that more focused diet and lifestyle interventions may be needed to improve risk factors and reduce CVD risk.Clinical Trials RegistrationClinicalTrials.gov Identifier: NCT00000611
TL;DR: The data demonstrate that the human ingestion of the flavanol (-)-epicatechin is, at least in part, causally linked to the reported vascular effects observed after the consumption of flavanol-rich cocoa.
Abstract: Epidemiological and medical anthropological investigations suggest that flavanol-rich foods exert cardiovascular health benefits. Endothelial dysfunction, a prognostically relevant key event in atherosclerosis, is characterized by a decreased bioactivity of nitric oxide (NO) and impaired flow-mediated vasodilation (FMD). We show in healthy male adults that the ingestion of flavanol-rich cocoa was associated with acute elevations in levels of circulating NO species, an enhanced FMD response of conduit arteries, and an augmented microcirculation. In addition, the concentrations and the chemical profiles of circulating flavanol metabolites were determined, and multivariate regression analyses identified (–)-epicatechin and its metabolite, epicatechin-7-O-glucuronide, as independent predictors of the vascular effects after flavanol-rich cocoa ingestion. A mixture of flavanols/metabolites, resembling the profile and concentration of circulating flavanol compounds in plasma after cocoa ingestion, induced a relaxation in preconstricted rabbit aortic rings ex vivo, thus mimicking acetylcholine-induced relaxations. Ex vivo flavanol-induced relaxation, as well as the in vivo increases in FMD, were abolished by inhibition of NO synthase. Oral administration of chemically pure (–)-epicatechin to humans closely emulated acute vascular effects of flavanol-rich cocoa. Finally, the concept that a chronic intake of high-flavanol diets is associated with prolonged, augmented NO synthesis is supported by data that indicate a correlation between the chronic consumption of a cocoa flavanol-rich diet and the augmented urinary excretion of NO metabolites. Collectively, our data demonstrate that the human ingestion of the flavanol (–)-epicatechin is, at least in part, causally linked to the reported vascular effects observed after the consumption of flavanol-rich cocoa.
TL;DR: It is demonstrated that the global population structure of M. tuberculosis is defined by six phylogeographical lineages, each associated with specific, sympatric human populations, and in an urban cosmopolitan environment, mycobacterial lineages were much more likely to spread in sympatrics than in allopatric patient populations.
Abstract: Mycobacterium tuberculosis remains a major cause of morbidity and mortality worldwide Studies have reported human pathogens to have geographically structured population genetics, some of which have been linked to ancient human migrations However, no study has addressed the potential evolutionary consequences of such longstanding human-pathogen associations Here, we demonstrate that the global population structure of M tuberculosis is defined by six phylogeographical lineages, each associated with specific, sympatric human populations In an urban cosmopolitan environment, mycobacterial lineages were much more likely to spread in sympatric than in allopatric patient populations Tuberculosis cases that did occur in allopatric hosts disproportionately involved high-risk individuals with impaired host resistance These observations suggest that mycobacterial lineages are adapted to particular human populations If confirmed, our findings have important implications for tuberculosis control and vaccine development
University at Buffalo1, Medical College of Wisconsin2, Fred Hutchinson Cancer Research Center3, Pfizer4, Memorial Hospital of Rhode Island5, University of Nevada, Reno6, University of Miami7, University of Minnesota8, University of Massachusetts Medical School9, Emory University10, National Institutes of Health11, University of California, Davis12, Yeshiva University13, University of Wisconsin-Madison14, Stanford University15, Northwestern University16, University of Iowa17, Kaiser Permanente18, University of Arizona19, University of Washington20, Rush University Medical Center21, Wake Forest University22, University of Texas at San Antonio23, University of California, Los Angeles24, University of California, San Diego25, University of Cincinnati26, Baylor College of Medicine27, University of North Carolina at Chapel Hill28, Wayne State University29, Howard University30, George Washington University31, University of California, Irvine32, Ohio State University33, University of Tennessee Health Science Center34, University of Pittsburgh35, Stony Brook University36, Rutgers University37, University of Alabama at Birmingham38, University of Florida39, Harvard University40
TL;DR: Daily supplementation of calcium with vitamin D for seven years had no effect on the incidence of colorectal cancer among postmenopausal women, and the long latency associated with the development of colorescopy cancer, along with the seven-year duration of the trial, may have contributed to this null finding.
Abstract: Background Higher intake of calcium and vitamin D has been associated with a reduced risk of colorectal cancer in epidemiologic studies and polyp recurrence in polyp-prevention trials. However, randomized-trial evidence that calcium with vitamin D supplementation is beneficial in the primary prevention of colorectal cancer is lacking. Methods We conducted a randomized, double-blind, placebo-controlled trial involving 36,282 postmenopausal women from 40 Women’s Health Initiative centers: 18,176 women received 500 mg of elemental calcium as calcium carbonate with 200 IU of vitamin D3 twice daily (1000 mg of elemental calcium and 400 IU of vitamin D3) and 18,106 received a matching placebo for an average of 7.0 years. The incidence of pathologically confirmed colorectal cancer was the designated secondary outcome. Baseline levels of serum 25-hydroxyvitamin D were assessed in a nested case–control study. Results The incidence of invasive colorectal cancer did not differ significantly between women assigned to calcium plus vitamin D supplementation and those assigned to placebo (168 and 154 cases; hazard ratio, 1.08; 95 percent confidence interval, 0.86 to 1.34; P = 0.51), and the tumor characteristics were similar in the two groups. The frequency of colorectal-cancer screening and abdominal symptoms was similar in the two groups. There were no significant treatment interactions with baseline characteristics. Conclusions Daily supplementation of calcium with vitamin D for seven years had no effect on the incidence of colorectal cancer among postmenopausal women. The long latency associated with the development of colorectal cancer, along with the seven-year duration of the trial, may have contributed to this null finding. Ongoing follow-up will assess the longer-term effect of this intervention. (ClinicalTrials.gov number, NCT00000611.)
TL;DR: The discovery of new bacterial and cyanobacterial members of the phytochrome family within the last decade has greatly aided biochemical and structural characterization of this family, with the first crystal structure of a bacteriophytochrome photosensory core appearing in 2005.
Abstract: Phytochromes are a widespread family of red/far-red responsive photoreceptors first discovered in plants, where they constitute one of the three main classes of photomorphogenesis regulators. All phytochromes utilize covalently attached bilin chromophores that enable photoconversion between red-absorbing (Pr) and far-red-absorbing (Pfr) forms. Phytochromes are thus photoswitchable photosensors; canonical phytochromes have a conserved N-terminal photosensory core and a C-terminal regulatory region, which typically includes a histidine-kinase-related domain. The discovery of new bacterial and cyanobacterial members of the phytochrome family within the last decade has greatly aided biochemical and structural characterization of this family, with the first crystal structure of a bacteriophytochrome photosensory core appearing in 2005. This structure and other recent biochemical studies have provided exciting new insights into the structure of phytochrome, the photoconversion process that is central to...
TL;DR: It is shown that in these species, the vernalization gene VRN3 is linked completely to a gene similar to Arabidopsis FLOWERING LOCUS T (FT), which results in a transmissible signal that promotes flowering.
Abstract: Winter wheat and barley varieties require an extended exposure to low temperatures to accelerate flowering (vernalization), whereas spring varieties do not have this requirement. In this study, we show that in these species, the vernalization gene VRN3 is linked completely to a gene similar to Arabidopsis FLOWERING LOCUS T (FT). FT induction in the leaves results in a transmissible signal that promotes flowering. Transcript levels of the barley and wheat orthologues, designated as HvFT and TaFT, respectively, are significantly higher in plants homozygous for the dominant Vrn3 alleles (early flowering) than in plants homozygous for the recessive vrn3 alleles (late flowering). In wheat, the dominant Vrn3 allele is associated with the insertion of a retroelement in the TaFT promoter, whereas in barley, mutations in the HvFT first intron differentiate plants with dominant and recessive VRN3 alleles. Winter wheat plants transformed with the TaFT allele carrying the promoter retroelement insertion flowered significantly earlier than nontransgenic plants, supporting the identity between TaFT and VRN-B3. Statistical analyses of flowering times confirmed the presence of significant interactions between vernalization and FT allelic classes in both wheat and barley (P < 0.0001). These interactions were supported further by the observed up-regulation of HvFT transcript levels by vernalization in barley winter plants (P = 0.002). These results confirmed that the wheat and barley FT genes are responsible for natural allelic variation in vernalization requirement, providing additional sources of adaptive diversity to these economically important crops.
TL;DR: It is found that adolescents with low self-esteem during adolescence had poorer mental and physical health, worse economic prospects, and higher levels of criminal behavior during adulthood, compared with adolescents with high self- esteem.
Abstract: Using prospective data from the Dunedin Multidisciplinary Health and Development Study birth cohort, the authors found that adolescents with low self-esteem had poorer mental and physical health, worse economic prospects, and higher levels of criminal behavior during adulthood, compared with adolescents with high self-esteem. The long-term consequences of self-esteem could not be explained by adolescent depression, gender, or socioeconomic status. Moreover, the findings held when the outcome variables were assessed using objective measures and informant reports; therefore, the findings cannot be explained by shared method variance in self-report data. The findings suggest that low self-esteem during adolescence predicts negative real-world consequences during adulthood.