University of Vermont

Rockström, J., W. Steffen, K. Noone, Å. Persson, F. S. Chapin, III, E. Lambin, T. M. Lenton, M. Scheffer, C. Folke, H. Schellnhuber, B. Nykvist, C. A. De Wit, T. Hughes, S. van der Leeuw, H. Rodhe, S. Sörlin, P. K. Snyder, R. Costanza, U. Svedin, M. Falkenmark, L. Karlberg, R. W. Corell, V. J. Fabry, J. Hansen, B. Walker, D. Liverman, K. Richardson, P. Crutzen, and J. Foley. 2009. Planetary boundaries:exploring the safe operating space for humanity. Ecology and Society 14(2): 32. https://doi.org/10.5751/ES-03180-140232

Species richness is a fundamental measurement of community and regional diversity, and it underlies many ecological models and conservation strategies. In spite of its importance, ecologists have not always appreciated the effects of abundance and sampling effort on richness measures and comparisons. We survey a series of common pitfalls in quantifying and comparing taxon richness. These pitfalls can be largely avoided by using accumulation and rarefaction curves, which may be based on either individuals or samples. These taxon sampling curves contain the basic information for valid richness comparisons, including category–subcategory ratios (species‐to‐genus and species‐to‐individual ratios). Rarefaction methods – both sample‐based and individual‐based – allow for meaningful standardization and comparison of datasets. Standardizing data sets by area or sampling effort may produce very different results compared to standardizing by number of individuals collected, and it is not always clear which measure of diversity is more appropriate. Asymptotic richness estimators provide lower‐bound estimates for taxon‐rich groups such as tropical arthropods, in which observed richness rarely reaches an asymptote, despite intensive sampling. Recent examples of diversity studies of tropical trees, stream invertebrates, and herbaceous plants emphasize the importance of carefully quantifying species richness using taxon sampling curves.

A key concern in Information Systems (IS) research has been to better understand the linkage between information systems and individual performance. The research reported in this study has two primary objectives: (1) to propose a comprehensive theoretical model that incorporates valuable insights from two complementary streams of research, and (2) to empirically test the core of the model. At the heart of the new model is the assertion that for an information technology to have a positive impact on individual performance, the technology: (1) must be utilized and (2) must be a good fit with the tasks it supports. This new model is moderately supported by an analysis of data from over 600 individuals in two companies. This research highlights the importance of the fit between technologies and users’ tasks in achieving individual performance impacts from information technology. It also suggests that task-technology fit, when decomposed into its more detailed components, could be the basis for a strong diagnostic tool to evaluate whether information systems and services in a given organization are meeting user needs.

BACKGROUND: Inflammation may be important in the pathogenesis of atherothrombosis. We studied whether inflammation increases the risk of a first thrombotic event and whether treatment with aspirin decreases the risk. METHODS: We measured plasma C-reactive protein, a marker for systemic inflammation, in 543 apparently healthy men participating in the Physicians' Health Study in whom myocardial infarction, stroke, or venous thrombosis subsequently developed, and in 543 study participants who did not report vascular disease during a follow-up period exceeding eight years. Subjects were randomly assigned to receive aspirin or placebo at the beginning of the trial. RESULTS: Base-line plasma C-reactive protein concentrations were higher among men who went on to have myocardial infarction (1.51 vs. 1.13 mg per liter, P<0.001) or ischemic stroke (1.38 vs. 1.13 mg per liter, P=0.02), but not venous thrombosis (1.26 vs. 1.13 mg per liter, P=0.34), than among men without vascular events. The men in the quartile with the highest levels of C-reactive protein values had three times the risk of myocardial infarction (relative risk, 2.9; P<0.001) and two times the risk of ischemic stroke (relative risk, 1.9; P=0.02) of the men in the lowest quartile. Risks were stable over long periods, were not modified by smoking, and were independent of other lipid-related and non-lipid-related risk factors. The use of aspirin was associated with significant reductions in the risk of myocardial infarction (55.7 percent reduction, P=0.02) among men in the highest quartile but with only small, nonsignificant reductions among those in the lowest quartile (13.9 percent, P=0.77). CONCLUSIONS: The base-line plasma concentration of C-reactive protein predicts the risk of future myocardial infarction and stroke. Moreover, the reduction associated with the use of aspirin in the risk of a first myocardial infarction appears to be directly related to the level of C-reactive protein, raising the possibility that antiinflammatory agents may have clinical benefits in preventing cardiovascular disease.

ADVERTISEMENT RETURN TO ISSUEPREVArticleChemical Redox Agents for Organometallic ChemistryNeil G. Connelly and William E. GeigerView Author Information School of Chemistry, University of Bristol, U.K., and Department of Chemistry, University of Vermont, Burlington, Vermont 05405-0125 Cite this: Chem. Rev. 1996, 96, 2, 877–910Publication Date (Web):March 28, 1996Publication History Received3 October 1995Revised9 January 1996Published online28 March 1996Published inissue 1 January 1996https://pubs.acs.org/doi/10.1021/cr940053xhttps://doi.org/10.1021/cr940053xresearch-articleACS PublicationsRequest reuse permissionsArticle Views89729Altmetric-Citations3552LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Oxidation,Reagents,Redox reactions,Salts,Solvents Get e-Alerts

Quantifying and assessing changes in biological diversity are central aspects of many ecological studies, yet accurate methods of estimating biological diversity from sampling data have been elusive. Hill numbers, or the effective number of species, are increasingly used to characterize the taxonomic, phylogenetic, or functional diversity of an assemblage. However, empirical estimates of Hill numbers, including species richness, tend to be an increasing function of sampling effort and, thus, tend to increase with sample completeness. Integrated curves based on sampling theory that smoothly link rarefaction (interpolation) and prediction (extrapolation) standardize samples on the basis of sample size or sample completeness and facilitate the comparison of biodiversity data. Here we extended previous rarefaction and extrapolation models for species richness (Hill number q D , where q = 0) to measures of taxon diversity incorporating relative abundance (i.e., for any Hill number q D , q &gt; 0) and present a unified approach for both individual‐based (abundance) data and sample‐based (incidence) data. Using this unified sampling framework, we derive both theoretical formulas and analytic estimators for seamless rarefaction and extrapolation based on Hill numbers. Detailed examples are provided for the first three Hill numbers: q = 0 (species richness), q = 1 (the exponential of Shannon's entropy index), and q = 2 (the inverse of Simpson's concentration index). We developed a bootstrap method for constructing confidence intervals around Hill numbers, facilitating the comparison of multiple assemblages of both rarefied and extrapolated samples. The proposed estimators are accurate for both rarefaction and short‐range extrapolation. For long‐range extrapolation, the performance of the estimators depends on both the value of q and on the extrapolation range. We tested our methods on simulated data generated from species abundance models and on data from large species inventories. We also illustrate the formulas and estimators using empirical data sets from biodiversity surveys of temperate forest spiders and tropical ants.

Abstract When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon. To image and study this phenomenon, we have assembled the Event Horizon Telescope, a global very long baseline interferometry array observing at a wavelength of 1.3 mm. This allows us to reconstruct event-horizon-scale images of the supermassive black hole candidate in the center of the giant elliptical galaxy M87. We have resolved the central compact radio source as an asymmetric bright emission ring with a diameter of 42 ± 3 μ as, which is circular and encompasses a central depression in brightness with a flux ratio ≳10:1. The emission ring is recovered using different calibration and imaging schemes, with its diameter and width remaining stable over four different observations carried out in different days. Overall, the observed image is consistent with expectations for the shadow of a Kerr black hole as predicted by general relativity. The asymmetry in brightness in the ring can be explained in terms of relativistic beaming of the emission from a plasma rotating close to the speed of light around a black hole. We compare our images to an extensive library of ray-traced general-relativistic magnetohydrodynamic simulations of black holes and derive a central mass of M = (6.5 ± 0.7) × 10 9 M ⊙ . Our radio-wave observations thus provide powerful evidence for the presence of supermassive black holes in centers of galaxies and as the central engines of active galactic nuclei. They also present a new tool to explore gravity in its most extreme limit and on a mass scale that was so far not accessible.

▪ Abstract Contributions from the field of population biology hold promise for understanding and managing invasiveness; invasive species also offer excellent opportunities to study basic processes in population biology. Life history studies and demographic models may be valuable for examining the introduction of invasive species and identifying life history stages where management will be most effective. Evolutionary processes may be key features in determining whether invasive species establish and spread. Studies of genetic diversity and evolutionary changes should be useful for understanding the potential for colonization and establishment, geographic patterns of invasion and range expansion, lag times, and the potential for evolutionary responses to novel environments, including management practices. The consequences of biological invasions permit study of basic evolutionary processes, as invaders often evolve rapidly in response to novel abiotic and biotic conditions, and native species evolve in response to the invasion.

There is broad consensus that good outcome measures are needed to distinguish interventions that are effective from those that are not. This task requires standardized, patient-centered measures that can be administered at a low cost. We developed a questionnaire to assess short- and long-term patient-relevant outcomes following knee injury, based on the WOMAC Osteoarthritis Index, a literature review, an expert panel, and a pilot study. The Knee injury and Osteoarthritis Outcome Score (KOOS) is self-administered and assesses five outcomes: pain, symptoms, activities of daily living, sport and recreation function, and knee-related quality of life. In this clinical study, the KOOS proved reliable, responsive to surgery and physical therapy, and valid for patients undergoing anterior cruciate ligament reconstruction. The KOOS meets basic criteria of outcome measures and can be used to evaluate the course of knee injury and treatment outcome.

Organizations continue to invest heavily in personal computers for their knowledge workers. When use is optional, however, having access to the technology by no means ensures it will be used or used effectively. To help us gain a better understanding of factors that influence the use of personal computers, researchers have recently adapted the theory of reasoned action proposed by Fishbein and Azjen (1975). This study uses a competing theory of behavior proposed by Triandis (1980). Responses were collected from 212 knowledge workers in nine divisions of a multi-national firm, and the measures and research hypotheses were analyzed using partial least squares (PLS). The results show that social norms and three components of expected consequences (complexity of use, fit between the job and PC capabilities, and long-term consequences) have a strong influence on utilization. These findings confirm the importance of the expected consequences of using PC technology, suggesting that training programs and organizational policies could be instituted to enhance or modify these expectations.

Microalgal biovolume is commonly calculated to assess the relative abundance (as biomass or carbon) of co‐occurring algae varying in shape and/or size. However, a standardized set of equations for biovolume calculations from microscopically measured linear dimensions that includes the entire range of microalgal shapes is not available yet. In comparison with automated methods, the use of microscopical measurements allows high taxonomic resolution, up to the species level, and has fewer sources of error. We present a set of geometric shapes and mathematical equations for calculating biovolumes of &gt;850 pelagic and benthic marine and freshwater microalgal genera. The equations are designed to minimize the effort of microscopic measurement. The similarities and differences between our proposal for standardization and previously published proposals are discussed and recommendations for quality standards given.

Significance Most nations recently agreed to hold global average temperature rise to well below 2 °C. We examine how much climate mitigation nature can contribute to this goal with a comprehensive analysis of “natural climate solutions” (NCS): 20 conservation, restoration, and/or improved land management actions that increase carbon storage and/or avoid greenhouse gas emissions across global forests, wetlands, grasslands, and agricultural lands. We show that NCS can provide over one-third of the cost-effective climate mitigation needed between now and 2030 to stabilize warming to below 2 °C. Alongside aggressive fossil fuel emissions reductions, NCS offer a powerful set of options for nations to deliver on the Paris Climate Agreement while improving soil productivity, cleaning our air and water, and maintaining biodiversity.

The reliability and validity of traditional taxonomies are limited by arbitrary boundaries between psychopathology and normality, often unclear boundaries between disorders, frequent disorder co-occurrence, heterogeneity within disorders, and diagnostic instability. These taxonomies went beyond evidence available on the structure of psychopathology and were shaped by a variety of other considerations, which may explain the aforementioned shortcomings. The Hierarchical Taxonomy Of Psychopathology (HiTOP) model has emerged as a research effort to address these problems. It constructs psychopathological syndromes and their components/subtypes based on the observed covariation of symptoms, grouping related symptoms together and thus reducing heterogeneity. It also combines co-occurring syndromes into spectra, thereby mapping out comorbidity. Moreover, it characterizes these phenomena dimensionally, which addresses boundary problems and diagnostic instability. Here, we review the development of the HiTOP and the relevant evidence. The new classification already covers most forms of psychopathology. Dimensional measures have been developed to assess many of the identified components, syndromes, and spectra. Several domains of this model are ready for clinical and research applications. The HiTOP promises to improve research and clinical practice by addressing the aforementioned shortcomings of traditional nosologies. It also provides an effective way to summarize and convey information on risk factors, etiology, pathophysiology, phenomenology, illness course, and treatment response. This can greatly improve the utility of the diagnosis of mental disorders. The new classification remains a work in progress. However, it is developing rapidly and is poised to advance mental health research and care significantly as the relevant science matures. (PsycINFO Database Record

Progress and issues in the study of coping with stress during childhood and adolescence are reviewed. Definitions of coping are considered, and the relationship between coping and other aspects of responses to stress (e.g., temperament and stress reactivity) is described. Questionnaire, interview, and observation measures of child and adolescent coping are evaluated with regard to reliability and validity. Studies of the association of coping with symptoms of psychopathology and social and academic competence are reviewed. Initial progress has been made in the conceptualization and measurement of coping, and substantial evidence has accumulated on the association between coping and adjustment. Problems still remain in the conceptualization and measurement of coping in young people, however, and aspects of the development and correlates of coping remain to be identified. An agenda for future research on child-adolescent coping is outlined.

This document has been approved by the AASLD, the Infectious Diseases Society of America, and the American College of Gastroenterology. These recommendations provide a data-supported approach to establishing guidelines. They are based on the following: (1) a formal review and analysis of the recently published world literature on the topic (Medline search up to September 2008); (2) the American College of Physicians' Manual for Assessing Health Practices and Designing Practice Guidelines;1 (3) guideline policies, including the American Association for the Study of Liver Diseases' (AASLD) Policy on the Development and Use of Practice Guidelines and the American Gastroenterological Association's Policy Statement on the Use of Medical Practice Guidelines;2 and (4) the experience of the authors in regard to hepatitis C. Intended for use by physicians, these recommendations suggest preferred approaches to the diagnostic, therapeutic and preventive aspects of care. They are intended to be flexible, in contrast to standards of care, which are inflexible policies to be followed in every case. Specific recommendations are based on relevant published information. To more fully characterize the quality of evidence supporting recommendations, the Practice Guidelines Committee of the AASLD requires a Class (reflecting benefit versus risk) and Level (assessing strength or certainty) of Evidence to be assigned and reported with each recommendation (Table 1, adapted from the American College of Cardiology and the American Heart association Practice Guidelines).3, 4 AASLD, American Association for the Study of Liver Diseases; ALT, alanine aminotransferase; ANC, absolute neutrophil count; anti-HCV, antibody to HCV; AST, aspartate aminotransferase; CKD, chronic kidney disease; CTP, Child-Turcotte-Pugh; EIA, enzyme immunoassay; ETR, end-of-treatment response; EVR, early virological response; FDA, U.S. Food and Drug Administration; HCV, hepatitis C virus; HIV, human immunodeficiency virus; PCR, polymerase chain reaction; PEG, polyethylene glycol; RVR, rapid virological response; SVR, sustained virological response; ULN, upper limit of normal. The hepatitis C virus (HCV) is a major public health problem and a leading cause of chronic liver disease.5 An estimated 180 million people are infected worldwide.6 In the United States (U.S.), the prevalence of HCV infection between the years 1999 and 2002 was 1.6%, equating to about 4.1 million persons positive for antibody to hepatitis C (anti-HCV), 80% of whom are estimated to be viremic.7 Hepatitis C is the principal cause of death from liver disease and the leading indication for liver transplantation in the U.S.8 Some calculations suggest that mortality related to HCV infection (death from liver failure or hepatocellular carcinoma) will continue to increase over the next two decades.9 The purpose of this document is to provide clinicians with evidence-based approaches to the prevention, diagnosis, and management of HCV infection. The optimal approach to detecting HCV infection is to screen persons for a history of risk of exposure to the virus, and to test selected individuals who have an identifiable risk factor.10 Currently, injection drug use is the primary mode of HCV transmission in the U.S; thus, all persons who use or have used illicit injection drugs in the present or past, even if only once, as well as intranasal drug users who share paraphernalia, should be tested for HCV infection.7, 11, 12 Individuals who have received a blood or blood component transfusion or an organ transplant before 1992 should also be tested. With the introduction of sensitive tests to screen blood donors for HCV antibodies in 1992, transfusion-transmission of HCV has become rare.12, 13 Persons with hemophilia should be tested for HCV infection if blood products were received before 1987, after which time, viral inactivation procedures were implemented.14 Similarly, individuals with unexplained elevations of the aminotransferase levels (alanine and/or aspartate aminotransferase; ALT/AST), those ever on hemodialysis, children born to HCV-infected mothers, or those with human immunodeficiency virus (HIV) infection should be tested for the presence of HCV infection.15-17 Other potential sources of HCV transmission include exposure to an infected sexual partner or multiple sexual partners, exposure among health care workers to HCV-contaminated blood and blood products, and tattooing.12, 15, 18-23 The prevalence of HCV infection is consistently higher among persons with multiple sexual partners, whereas sexual transmission of HCV between monogamous partners is uncommon.11, 18 Thus, although it is prudent to counsel HCV-infected persons to notify their current partners of their HCV status, they should be informed that the risk of sexual transmission is sufficiently low19 that many authorities do not advise the use of barrier protection among monogamous couples.18 Nevertheless, between 1% and 5% of monogamous sexual partners of index HCV cases test positive for anti-HCV. There is no need for HCV-infected persons to limit ordinary household activities except for those that might result in blood exposure, such as sharing a razor or toothbrush. The hepatitis C virus is not transmitted by hugging, kissing, sharing of eating utensils or breastfeeding. Folk medicine practices, including acupuncture and ritual scarification, as well as body piercing, tattooing and commercial barbering are potential modes for transmission of HCV infection when performed without appropriate infection control measures.24-28 Transmission of HCV infection by body piercing is, however, rare and many HCV infected persons who have undergone body piercing acquired their infection by other means.23, 29-33 Therefore, there is no need to routinely test persons who have received tattoos or undergone piercings in the absence of other risk factors, particularly if these procedures have taken place in licensed establishments. Because symptoms are generally absent in individuals with chronic HCV infection, recognition of infection requires risk factor screening, which should be done whenever it is possible to link with appropriate HCV testing and counseling.10 Table 2 outlines the list of persons who should be routinely screened for HCV infection.15 For some groups, such as those with a history of injection drug use or persons with hemophilia, the prevalence of HCV is high (≈90%). For other groups (recipients of blood transfusions prior to 1992), the prevalence is moderate (≈10%). For still others, (persons with needle stick exposure, sexual partners of HCV-infected persons), the prevalence is low (1% to 5%). ○ Persons with HIV infection ○ Persons with hemophilia who received clotting factor concentrates prior to 1987 ○ Persons who have ever been on hemodialysis ○ Persons with unexplained abnormal aminotransferase levels ○ Persons who were notified that they had received blood from a donor who later tested positive for HCV infection ○ Persons who received a transfusion of blood or blood products ○ Persons who received an organ transplant Recommendation 1. As part of a comprehensive health evaluation, all persons should be screened for behaviors that place them at high risk for HCV infection. (Class I, level B). 2. Persons who are at risk should be tested for the presence of HCV infection (Table2) (Class I, level B). Good clinical practice dictates that persons found to be HCV-infected are counseled regarding prevention of spread of the virus to others. Because exposure to infected blood is the primary mode of transmission, it is essential to inform HCV-infected individuals that precautions should be taken to avoid the possibility of exposing others to contact with their blood. This is particularly important for injection drug users who are the leading source of HCV infection, because their transmission route is primarily via sharing of needles and other infected implements. Table 3 outlines the measures to avoid HCV transmission. Recommendation 3. Persons infected with HCV should be counseled on how to avoid HCV transmission to others, as indicated in Table3 (Class I, level C) Two classes of assays are used in the diagnosis and management of HCV infection: serologic assays that detect specific antibody to hepatitis C virus (anti-HCV) and molecular assays that detect viral nucleic acid. These assays have no role in the assessment of disease severity or prognosis. Tests that detect anti-HCV are used both to screen for and to diagnose HCV infection. Anti-HCV can be detected in the serum or plasma using a number of immunoassays. Two enzyme immunoassays (EIAs) are approved by the U.S. Food and Drug Administration (FDA) for clinical use, Abbott HCV EIA 2.0 (Abbott Laboratories, Abbott Park, IL) and ORTHO® HCV Version 3.0 ELISA (Ortho-Clinical Diagnostics, Raritan, NJ), as well as one enhanced chemiluminescence immunoassay (CIA) VITROS® Anti-HCV assay, (Ortho-Clinical Diagnostics, Raritan, NJ). The specificity of current EIAs for anti-HCV is greater than 99%.34 False positive results are more likely to occur when testing is performed among populations where the prevalence of hepatitis C is low. False negative results may occur in the setting of severe immunosuppression such as infection with HIV, solid organ transplant recipients, hypo- or aggammaglobulinemia or in patients on hemodialysis.35-37 The recombinant immunoblot assay, Chiron RIBA HCV 3.0 SIA (Chiron Corporation, Emeryville, CA) is also FDA approved. This assay was originally developed as a more specific, supplemental assay to confirm the results of EIA testing.38, 39 However, specificity is extremely high for third generation EIA results that exceed particular signal/cutoff ratios (e.g., >3.8 for the above mentioned Ortho and Abbott EIA tests). Given the widespread availability of nucleic acid testing, the role for RIBA testing in HCV diagnosis and management has all but disappeared.40, 41 The list of commercial assays available for the detection (qualitative assays) or quantification (quantitative assays) of HCV RNA is shown in Tables 4 and 5. Historically, qualitative assays have been more sensitive than quantitative assays. With the recent availability of real time polymerase chain reaction (PCR)-based assays and transcription-mediated amplification (TMA) assays, with sensitivities of 10-50 IU/mL, there is no longer need for qualitative assays.42, 43 A highly sensitive assay with this lower limit of detection is considered appropriate for monitoring during therapy. All currently available assays have excellent specificity, in the range of 98% to 99%. In 1997, the World Health Organization established the first International standard for HCV RNA nucleic acid technology,44 and the IU rather than viral copies is now the preferred unit to report test results.44, 45 For monitoring purposes, it is important to use the same laboratory test before and during therapy. Genotyping is useful in epidemiological studies and in clinical management for predicting the likelihood of response and determining the optimal duration of therapy. The hepatitis C virus can be classified into at least 6 major genotypes (genotypes 1 to 6) based on a sequence divergence of 30% among isolates.46 Genotype 1 (subtypes 1a and 1b) is the most common in the U.S., followed by genotypes 2 and 3. Less common genotypes (genotypes 4-6) are beginning to be observed more frequently because of the growing cultural diversity within the United States.47 Several commercial assays are available to determine HCV genotypes using direct sequence analysis of the 5′ non-coding region, that include Trugene 5′NC HCV Genotyping kit (Siemens Healthcare Diagnostics Division, Tarrytown, NY), reverse hybridization analysis using genotype specific oligonucleotide probes located in the 5′ non-coding region, INNO-LiPa HCV II, (Innogenetics, Ghent, Belgium), and Versant HCV Genotyping Assay 2.0 (Siemens Healthcare Diagnostics Division, Tarrytown, NY). Incorrect typing among the major genotypes is rare (<3%) and mixed genotypes occur but are uncommon. Occasionally (<5%), tested samples cannot be genotyped. This usually results from low viral levels, issues with the PCR amplification step of the assay, or extreme nucleotide variability within the HCV genome.48 The diagnosis of acute or chronic HCV infection generally requires testing of serum for both antibody to HCV (anti-HCV) and for HCV RNA. A sensitive quantitative HCV RNA assay is recommended for diagnosis because it also provides information on the level of virus which is helpful in management. The differentiation of acute from chronic HCV infection depends on the clinical presentation: namely the presence of symptoms or jaundice, and whether or not there was a prior history of ALT elevation and its duration. After acute exposure, HCV RNA is usually detected in serum before antibody; HCV RNA can be identified as early as 2 weeks following exposure whereas anti-HCV is generally not detectable before 8-12 weeks. These two markers of HCV infection may be present in varying permutations, requiring careful analysis for interpretation (Table 6). One pattern is the identification of both anti-HCV and HCV RNA in a person with recent elevation of the ALT value. This scenario is consistent with either acute HCV infection when there is a recent known risk exposure, with exacerbation of chronic HCV infection, or with an acute hepatitis of another etiology in a patient with chronic HCV infection. Another pattern is the detection of anti-HCV but with a negative test for HCV RNA. This may represent acute HCV infection during a period of transient clearance of HCV RNA, a false positive or negative result or, more commonly, recovery from HCV infection. Re-testing for HCV RNA 4-6 months later is recommended to confirm the resolution of HCV infection. The reverse scenario — a negative anti-HCV test but a positive result for HCV RNA — is compatible with the early stage of acute infection prior to the development of antibody or may represent chronic infection in an immunosuppressed individual. Alternatively, it may represent a false positive HCV RNA result. In all circumstances, re-testing for anti-HCV and HCV RNA in 4-6 months should resolve the issue. Finally, if the patient has raised ALT values but the tests for anti-HCV and HCV RNA are negative, both acute and chronic hepatitis C may be excluded and another diagnosis should be considered. Antibody testing should be repeated in 4-6 months for confirmation purposes. Recommendation 4. Patients suspected of having acute or chronic HCV infection should first be tested for anti-HCV (Class I, Level B.) 5. HCV RNA testing should be performed in: a) Patients with a positive anti-HCV test (Class I, Level B) b) Patients for whom antiviral treatment is being considered, using a sensitive quantitative assay (Class I, Level A) c) Patients with unexplained liver disease whose anti-HCV test is negative and who are immunocompromised or suspected of having acute HCV infection (Class I, Level B). 6. HCV genotyping should be performed in all HCV-infected persons prior to interferon-based treatment in order to plan for the dose and duration of therapy and to estimate the likelihood of response (Class I, Level A) There are three primary reasons for performing a liver biopsy: it provides helpful information on the current status of the liver injury, it identifies features useful in the decision to embark on therapy, and it may reveal advanced fibrosis or cirrhosis that necessitates surveillance for hepatocellular carcinoma (HCC) and/or screening for varices. The biopsy is assessed for grade and stage of the liver injury, but also provides information on other histological features that might have a bearing on liver disease progression.49 The grade defines the extent of necroinflammatory activity, while the stage establishes the extent of fibrosis or the presence of cirrhosis. Several scoring systems have been conceived, the most common being the French METAVIR, the Batts-Ludwig, the International Association for the Study of the Liver (IASL) and the Ishak Scoring systems.50-54 (Table 7). The two more common non-HCV conditions that might affect disease progression and possibly impede treatment response are steatosis49, 55, 56 and excess hepatocellular iron.57 Identifying either of these two features does not preclude initiating treatment, but their presence provides additional information regarding the likelihood of response to treatment.58-60 The liver biopsy has been widely regarded as the "gold standard" for defining the liver disease status, but it has drawbacks that have prompted questions about its value.61, 62 The procedure is not without risks (including pain, bleeding and perforation of other organs),63, 64 it is subject to sampling error,65 it requires special expertise for interpreting the histopathology, it adds cost to medical care, and it is anxiety-provoking for the implicated person. Thus, efforts are underway to seek alternative means of establishing information on the extent of fibrosis by focusing on noninvasive blood marker panels.66 These markers are useful for establishing the two ends of the fibrosis spectrum (minimal fibrosis and cirrhosis) but are less helpful in assessing the mid-ranges of fibrosis or for tracking fibrosis progression.66 The recently developed transient elastography that uses ultrasound and low frequency elastic waves to measure liver elasticity67 has improved the ability to define the extent of fibrosis without a liver biopsy, particularly when combined with other noninvasive markers.68 However, it is not yet ready to replace the liver biopsy since it is not FDA approved, the failure rate is higher in obese patients, and there is now evidence that the transient elastography score can be unexpectedly increased in persons with acute hepatitis who have high necroinflammatory activity but no or minimal fibrosis.69, 70 A liver biopsy may be unnecessary in persons with genotypes 2 and 3 HCV infection, since more than 80% of them achieve a sustained virlogical response (SVR) to standard-of-care treatment. There is, however, an ongoing debate about whether a biopsy is warranted for persons infected with HCV, genotype 1, whose response to such treatment approximates 50% among Caucasians and 30% among African Americans.71-73 Even more uncertain is whether there is need for a liver biopsy in persons infected with the other less common genotypes (4 through 6). Thus, although the liver biopsy was previously regarded as routine for defining the fibrosis stage in persons with genotype 1 infection,62 the issue is now in a state of flux and possible transition. Supporters of a biopsy cite the difficult nature and high cost of current antiviral therapy and are to or treatment if liver minimal to moderate fibrosis stage (Table if the infection is known to have been These individuals are regarded as having liver disease that may not be for their However, treatment is for those with more advanced fibrosis stage (Table be however, that while information from a biopsy is the procedure is not for on treatment. performed and treatment is a common is to the liver biopsy 4 to years later and to treatment should there be evidence of disease The that persons with genotype 1 infection and aminotransferase values not a liver biopsy because they were to have minimal liver and that treatment may be are no longer is now that as many as a of such individuals have and that treatment response is to that of individuals with abnormal serum aminotransferase Therefore, the decision to a liver biopsy should be based on whether treatment is being considered, into the estimated duration of infection and other of liver disease (e.g., the the viral and the to a liver biopsy and to be the biopsy is not performed and treatment not the patient should continue to be at least and a biopsy performed if the aminotransferase values become abnormal and other of liver disease become A liver biopsy should be considered in patients with chronic hepatitis C infection if the patient and health care information regarding fibrosis stage for or to a decision regarding treatment (Class Level B) available noninvasive tests may be useful in defining the presence or absence of advanced fibrosis in persons with chronic hepatitis C infection, but should not replace the liver biopsy in routine clinical practice (Class Level history studies that to of individuals who acute hepatitis C will resolution is more common among infected and than among persons who are when they acute HCV infection has for the infected persons as well as for their the are at risk for progression to cirrhosis and/or the are at risk of the infection through exposure to the The risk of cirrhosis from 5% to over of to studies of and children infected at a and followed for to years report low of 1% to studies of patients to care document higher of to but this may be by to cirrhosis may be in persons who are of who are who are immunosuppressed (e.g., HIV and who more than of although the of with fibrosis progression is Persons with cirrhosis are at risk for the development of over as well as hepatocellular carcinoma (1% to Identifying individuals at risk for disease is the preferred approach is to the of fibrosis on liver biopsy, using a such as the or Persons with no or minimal fibrosis stage and stage have a low risk for and death the next to However, the presence of fibrosis stage Table is an important of progression to cirrhosis and an indication for with HCV can also cause including mixed and is an indication for HCV antiviral therapy of the stage of liver on of Patients with The of therapy is to and death from HCV infection. Because of the of chronic HCV infection over it has been difficult to that therapy of liver treatment are by a virological rather than a clinical can be of serum ALT of HCV RNA from serum by a sensitive and in necroinflammatory score with no in fibrosis Several of virological may to their to treatment. The most important is the sustained virological response as the absence of HCV RNA from serum by a sensitive PCR assay weeks following of therapy (Table This is generally regarded as a although liver has been identified years if cirrhosis at the time of an of virological RVR, rapid virological response of HCV from serum by 4 using a sensitive EVR, early virological response in HCV RNA level to HCV RNA level or HCV RNA negative at treatment SVR, sustained virological response RNA negative weeks after of of HCV RNA in serum after therapy is failure to HCV RNA from serum after weeks of 2 in HCV RNA but still HCV RNA positive at failure to HCV RNA by 2 after of therapy. virus at the of either a or of therapy is to as an end-of-treatment response An does not that an will be but is for it to A rapid virological response as HCV RNA at 4 of treatment, using a sensitive test with a lower limit of detection of IU/mL, a high likelihood of an An early virological response is as a or absence of serum HCV RNA at 12 of therapy with the to achieve an is the most of not an viral is useful for predicting whether or not an is likely to to the of HCV RNA while still on therapy, while virological is the of HCV RNA in serum after treatment is and an was Persons who to serum HCV RNA by at least 2 after weeks of therapy are while those whose HCV RNA levels by but become are to as The currently recommended therapy of chronic HCV infection is the of a and The of this was based the results of three clinical that the of this treatment over standard and not these three of therapy, namely the appropriate dose of the the optimal duration of therapy and the need for a for patients with genotype 1 and genotype 2 and 3 There are two licensed in the United NJ), with a polyethylene to the standard and with a to the standard The of these two of The optimal dose of based on the is to body the dose of used in the was at a of patients with genotype 1 infection that for patients for patients to for patients to and for patients but was more to and in the two U.S. ETR, end-of-treatment response; SVR, sustained virological is at a dose of 180 with to for those who and for those who The the two of an in the more a in the rate as to treatment. A third that the optimal duration of treatment should be based on the viral The established that patients with genotype 1 should be for weeks with standard whereas patients with genotypes 2 and 3 be with low dose for For patients with HCV genotype 4 infection, treatment with for weeks to be the optimal as in a of from another of treatment with a dose of has that weeks duration of therapy is an is these results need to be Patients with genotypes and 6 are in of and to their A recent analysis of the treatment of patients

BACKGROUND: In white populations, computed tomographic measurements of coronary-artery calcium predict coronary heart disease independently of traditional coronary risk factors. However, it is not known whether coronary-artery calcium predicts coronary heart disease in other racial or ethnic groups. METHODS: We collected data on risk factors and performed scanning for coronary calcium in a population-based sample of 6722 men and women, of whom 38.6% were white, 27.6% were black, 21.9% were Hispanic, and 11.9% were Chinese. The study subjects had no clinical cardiovascular disease at entry and were followed for a median of 3.8 years. RESULTS: There were 162 coronary events, of which 89 were major events (myocardial infarction or death from coronary heart disease). In comparison with participants with no coronary calcium, the adjusted risk of a coronary event was increased by a factor of 7.73 among participants with coronary calcium scores between 101 and 300 and by a factor of 9.67 among participants with scores above 300 (P<0.001 for both comparisons). Among the four racial and ethnic groups, a doubling of the calcium score increased the risk of a major coronary event by 15 to 35% and the risk of any coronary event by 18 to 39%. The areas under the receiver-operating-characteristic curves for the prediction of both major coronary events and any coronary event were higher when the calcium score was added to the standard risk factors. CONCLUSIONS: The coronary calcium score is a strong predictor of incident coronary heart disease and provides predictive information beyond that provided by standard risk factors in four major racial and ethnic groups in the United States. No major differences among racial and ethnic groups in the predictive value of calcium scores were detected.

We present two standards developed by the Genomic Standards Consortium (GSC) for reporting bacterial and archaeal genome sequences. Both are extensions of the Minimum Information about Any (x) Sequence (MIxS). The standards are the Minimum Information about a Single Amplified Genome (MISAG) and the Minimum Information about a Metagenome-Assembled Genome (MIMAG), including, but not limited to, assembly quality, and estimates of genome completeness and contamination. These standards can be used in combination with other GSC checklists, including the Minimum Information about a Genome Sequence (MIGS), Minimum Information about a Metagenomic Sequence (MIMS), and Minimum Information about a Marker Gene Sequence (MIMARKS). Community-wide adoption of MISAG and MIMAG will facilitate more robust comparative genomic analyses of bacterial and archaeal diversity.

The inhalation of airborne pollutants, such as asbestos or silica, is linked to inflammation of the lung, fibrosis, and lung cancer. How the presence of pathogenic dust is recognized and how chronic inflammatory diseases are triggered are poorly understood. Here, we show that asbestos and silica are sensed by the Nalp3 inflammasome, whose subsequent activation leads to interleukin-1beta secretion. Inflammasome activation is triggered by reactive oxygen species, which are generated by a NADPH oxidase upon particle phagocytosis. (NADPH is the reduced form of nicotinamide adenine dinucleotide phosphate.) In a model of asbestos inhalation, Nalp3-/- mice showed diminished recruitment of inflammatory cells to the lungs, paralleled by lower cytokine production. Our findings implicate the Nalp3 inflammasome in particulate matter-related pulmonary diseases and support its role as a major proinflammatory "danger" receptor.

Honeybees Can't Do It Alone The majority of food crops require pollination to set fruit with the honeybee providing a pollination workhorse, with both feral and managed populations an integral component of crop management (see the Perspective by Tylianakis , published online 28 February). Garibaldi et al. (p. 1608 , published online 28 February) now show that wild pollinators are also a vital part of our crop systems. In more than 40 important crops grown worldwide, wild pollinators improved pollination efficiency, increasing fruit set by twice that facilitated by honeybees. Burkle et al. (p. 1611 , published online 28 February) took advantage of one of the most thorough and oldest data sets available on plant-pollinator interaction networks and recollected data on plant-pollinator interactions after more than 120 years of climate change and landscape alteration. The historical data set consists of observations collected by Charles Robertson near Carlinville, Illinois (USA), in the late 1800s on the phenology of plants and their pollinating insects, as well as information about which plants and pollinators interacted with one another. Many sites were revisited in the early 1970s and in 2009 and 2010 to collect similar plant-pollinator data. Pollinator function has declined through time, with bees showing lower visitation rates and lower fidelity to individual plant species.

Recent studies have suggested that the intestinal microbiome plays an important role in modulating risk of several chronic diseases, including inflammatory bowel disease, obesity, type 2 diabetes, cardiovascular disease, and cancer. At the same time, it is now understood that diet plays a significant role in shaping the microbiome, with experiments showing that dietary alterations can induce large, temporary microbial shifts within 24 h. Given this association, there may be significant therapeutic utility in altering microbial composition through diet. This review systematically evaluates current data regarding the effects of several common dietary components on intestinal microbiota. We show that consumption of particular types of food produces predictable shifts in existing host bacterial genera. Furthermore, the identity of these bacteria affects host immune and metabolic parameters, with broad implications for human health. Familiarity with these associations will be of tremendous use to the practitioner as well as the patient.