Atmospheric reduced nitrogen: Sources, transformations, effects, and management.

Human activities have increased atmospheric emissions and deposition of oxidized and reduced forms of nitrogen, but emission control programs have largely focused on oxidized nitrogen. As a result, in many regions of the world emissions of oxidized nitrogen are decreasing while emissions of reduced nitrogen are increasing. Emissions of reduced nitrogen largely originate from livestock waste and fertilizer application, with contributions from transportation sources in urban areas. Observations suggest a discrepancy between trends in emissions and deposition of reduced nitrogen in the U.S., likely due to an underestimate in emissions. In the atmosphere, ammonia reacts with oxides of sulfur and nitrogen to form fine particulate matter that impairs health and visibility and affects climate forcings. Recent reductions in emissions of sulfur and nitrogen oxides have limited partitioning with ammonia, decreasing long-range transport. Continuing research is needed to improve understanding of how shifting emissions alter formation of secondary particulates and patterns of transport and deposition of reactive nitrogen. Satellite remote sensing has potential for monitoring atmospheric concentrations and emissions of ammonia, but there remains a need to maintain and strengthen ground-based measurements and continue development of chemical transport models. Elevated nitrogen deposition has decreased plant and soil microbial biodiversity and altered the biogeochemical function of terrestrial, freshwater, and coastal ecosystems. Further study is needed on differential effects of oxidized versus reduced nitrogen and pathways and timescales of ecosystem recovery from elevated nitrogen deposition. Decreases in deposition of reduced nitrogen could alleviate exceedances of critical loads for terrestrial and freshwater indicators in many U.S. areas. The U.S. Environmental Protection Agency should consider using critical loads as a basis for setting standards to protect public welfare and ecosystems. The U.S. and other countries might look to European experience for approaches to control emissions of reduced nitrogen from agricultural and transportation sectors.Implications: In this Critical Review we synthesize research on effects, air emissions, environmental transformations, and management of reduced forms of nitrogen. Emissions of reduced nitrogen affect human health, the structure and function of ecosystems, and climatic forcings. While emissions of oxidized forms of nitrogen are regulated in the U.S., controls on reduced forms are largely absent. Decreases in emissions of sulfur and nitrogen oxides coupled with increases in ammonia are shifting the gas-particle partitioning of ammonia and decreasing long-range atmospheric transport of reduced nitrogen. Effort is needed to understand, monitor, and manage emissions of reduced nitrogen in a changing environment.

Updating Normal Organ Weights Using a Large Current Sample Database.

CONTEXT.­: Organ weights are an essential part of autopsy analysis. Deviations from normal organ weights provide important clues to disease processes. The assessment of normal organ weights depends on reliable reference tables, but most widely available reference tables are based on data that are either decades old or derived from relatively small sample sizes. OBJECTIVE.­: To provide an updated reference table of organ weights based on contemporary sources and a large sample size. DESIGN.­: Organ weights from 4197 carefully screened autopsies performed on adults at the Palm Beach County Medical Examiner's Office in West Palm Beach, Florida, and the Mayo Clinic Hospital in Rochester, Minnesota. RESULTS.­: Height and body weight data in this study reflect the well-recognized increases in both variables, but most particularly in body weight, seen during the last decades. The study data show a strong positive association between organ weight and body weight for the heart, liver, and spleen. There is a similar but weaker association between body weight and the weight of the lungs and kidneys. Brain weight is independent of body weight but shows a strong negative association with age. Even when controlling for body weight, men's organs are heavier, except for the weight of the liver, which is comparable in men and women. These associations are in agreement with the findings of previous studies. The current study suggests that, for some of the commonly weighed organs, there has been an increase in median organ weight when compared with existing references. CONCLUSIONS.­: The tables presented here provide an updated reference that should prove useful to autopsy pathologists in the forensic and hospital settings.

Aspects of uncertainty in total reactive nitrogen deposition estimates for North American critical load applications.

Determination of the amount of reactive nitrogen (Nr) deposition in excess of the ecosystem critical load (CL) requires an estimate of total deposition. Because the CL exceedance is used to inform policy decisions, uncertainty in both the CL and the exceedance itself must be understood. In this paper we review the state of the science with respect to the sources of uncertainty in total Nr deposition budgets used for CL assessments in North America and put forth recommendations for research and monitoring to improve deposition measurements and models. In the absence of methods to rigorously quantify uncertainty in total Nr deposition, a simple weighted deposition uncertainty metric (WDUM) is introduced as a tool for scientists and decision makers to use in assessing CL exceedances. Maps of the WDUM applied to National Atmospheric Deposition Program (NADP) Total Deposition (TDep) estimates show greater uncertainty in areas of the U.S. where dry deposition makes a larger contribution to the deposition budget, particularly ammonia (NH3) in agricultural areas and oxidized nitrogen (NOx) in urban areas. Organic N deposition is an important source of uncertainty over much of the U.S. Our analysis illustrates how the WDUM can be used to assess spatial patterns of deposition uncertainty and inform actions to improve deposition budgets for CL assessments at the local scale.

Environmental change, shifting distributions, and habitat conservation plans: A case study of the California gnatcatcher.

Many species have already experienced distributional shifts due to changing environmental conditions, and analyzing past shifts can help us to understand the influence of environmental stressors on a species as well as to analyze the effectiveness of conservation strategies. We aimed to (1) quantify regional habitat associations of the California gnatcatcher (Polioptila californica); (2) describe changes in environmental variables and gnatcatcher distributions through time; (3) identify environmental drivers associated with habitat suitability changes; and (4) relate habitat suitability changes through time to habitat conservation plans. Southern California's Western Riverside County (WRC), an approximately 4,675 km2 conservation planning area. We assessed environmental correlates of distributional shifts of the federally threatened California gnatcatcher (hereafter, gnatcatcher) using partitioned Mahalanobis D2 niche modeling for three time periods: 1980-1997, 1998-2003, and 2004-2012, corresponding to distinct periods in habitat conservation planning. Highly suitable gnatcatcher habitat was consistently warmer and drier and occurred at a lower elevation than less suitable habitat and consistently had more CSS, less agriculture, and less chaparral. However, its relationship to development changed among periods, mainly due to the rapid change in this variable. Likewise, other aspects of highly suitable habitat changed among time periods, which became cooler and higher in elevation. The gnatcatcher lost 11.7% and 40.6% of highly suitable habitat within WRC between 1980-1997 to 1998-2003, and 1998-2003 to 2004-2012, respectively. Unprotected landscapes lost relatively more suitable habitat (-64.3%) than protected landscapes (30.5%). Over the past four decades, suitable habitat loss within WRC, especially between the second and third time periods, was associated with temperature-related factors coupled with landscape development across coastal sage scrub habitat; however, development appears to be driving change more rapidly than climate change. Our study demonstrates the importance of providing protected lands for potential suitable habitat in future scenarios.

A framework to quantify the strength of ecological links between an environmental stressor and final ecosystem services.

Anthropogenic stressors such as climate change, increased fire frequency, and pollution drive shifts in ecosystem function and resilience. Scientists generally rely on biological indicators of these stressors to signal that ecosystem conditions have been altered. However, these biological indicators are not always capable of being directly related to ecosystem components that provide benefits to humans and/or can be used to evaluate the cost-benefit of a change in health of the component (ecosystem services). Therefore, we developed the STEPS (STressor - Ecological Production function - final ecosystem Services) Framework to link changes in a biological indicator of a stressor to final ecosystem services. The STEPS framework produces "chains" of ecological components that explore the breadth of impacts resulting from the change of a stressor. Chains are comprised of the biological indicator, the ecological production function (EPF; which uses ecological components to link the biological indicator to a final ecosystem service), and the user group who directly uses, appreciates, or values the component. The framework uses a qualitative score (High, Medium, Low) to describe the Strength of Science (SOS) for the relationship between each component in the EPF. We tested the STEPS Framework within a workshop setting using the exceedance of critical loads of air pollution as a model stressor and the Final Ecosystem Goods and Services Classification System (FEGS-CS) to describe final ecosystem services. We identified chains for four modes of ecological response to deposition: aquatic acidification, aquatic eutrophication, terrestrial acidification, and terrestrial eutrophication. The workshop participants identified 183 unique EPFs linking a change in a biological indicator to a FEGS; and when accounting for the multiple beneficiaries, we ended with 1104 chains. The SOS scores were effective in identifying chains with the highest confidence ranking as well as those where more research is needed. The STEPS framework could be adapted to any system in which a stressor is modifying a biological component. The results of the analysis can be used by the social science community to apply valuation measures to multiple or selected chains, providing a comprehensive analysis of the effects of anthropogenic stressors on measures of human well-being.

Prognostic value of urinary cytology and other biomarkers for recurrence and progression in bladder cancer: a prospective study.

PURPOSE: Urinary cytology (C) and cystoscopy remain the gold standard for the detection and screening of bladder cancer (BC). In this prospective study, we analyzed whether baseline C, ImmunoCyt (I), BTA Stat (B), hemoglobin dipstick (H), and NMP22 BladderChek (N) can predict recurrence and progression. METHODS: Urinary samples from 91 patients with BC were prospectively collected over an 18-month period. Baseline characteristics of the population included patient demographics, various clinicopathological variables and use of intravesical therapy. Progression and recurrence were then assessed after a median follow-up of 48 months (IQR 23.7-59.5). Univariate and multivariate analyses were performed using COX proportional hazards models. RESULTS: On univariate analysis, C (HR 1.36; p = 0.26), I (HR 0.89; p = 0.66), B (HR 0.80; p = 0.42), H (HR 0.75; p = 0.30), and N (HR 0.82; p = 0.48) were not associated with recurrence-free survival (RFS). With regard to progression-free survival (PFS), C was significantly prognostic (HR 2.67; p = 0.017), whereas I, B, H, and N were not. On multivariable analysis, NMP22 was the only marker to be independently associated with RFS (HR 0.41, p < 0.01) and PFS (HR 0.32, p = 0.02). CONCLUSION: Based on the results of this study, baseline C, B, I, and H were not independently prognostic. Prognostic impact of NMP22 requires further validation in a multicenter larger study.

Sclerosing epithelioid fibrosarcoma metastasizing to the penile shaft.

We present the case of a 50-year-old man with a periurethral mass. He was previously known for sclerosing epithelioid fibrosarcoma (SEF) of the left foot, having an amputation for local recurrence with >2 cm negative margins. A solid periurethral mass was surgically excised seven months later, yielding the diagnosis of metastatic SEF. This is the first documented metastasis of SEF to the penis. These sarcomas have proven difficult to treat, with high recurrence rates despite a multimodal approach.

Correcting for background nitrate contamination in KCl-extracted samples during isotopic analysis of oxygen and nitrogen by the denitrifier method.

RATIONALE: Previous research has shown that the denitrifying bacteria Pseudomonas chlororaphis ssp. aureofaciens (P. aureofaciens) can be used to measure the δ(15)N and δ(18)O values of extracted soil nitrate (NO3(-)) by isotope ratio mass spectrometry. We discovered that N2O production from reference blanks made in 1 M KCl increased relative to blanks made of deionized water (DIW). Further investigation showed that isotopic standards made in KCl yielded δ(15)N and δ(18)O values different from the standards prepared in DIW. METHODS: Three grades of crystalline KCl were dissolved in DIW to create solutions of increasing molarity (0.1 M to 2 M), which were added to P. aureofaciens broth and measured as blanks. Reference standards USGS-32, USGS-34, and USGS-35 were then dissolved in a range of KCl concentrations to measure isotopic responses to changing KCl molarity. Reference blanks and standards created in DIW were analyzed as controls to measure the impact of KCl on the δ(15)N and δ(18)O values. RESULTS: The amount of N2O in the KCl blanks increased linearly with increasing molarity, but at different rates for each KCl grade. The isotopic values of the reference standards measured in KCl were systematically different from those measured in DIW, suggesting contamination by background NO3(-) in the KCl reagents. However, we also noted reduced conversion of NO3(-) into N2O as the KCl molarity increased, suggesting there is a physiological response of P. aureofaciens to KCl. CONCLUSIONS: There is a small amount of NO3(-) present in crystalline KCl, which can bias isotopic measurement of NO3(-) at low sample concentrations. This can be minimized by making standards and blanks in the same KCl as is used in samples, diluting all samples and standards to the appropriate NO3(-) concentration using matched KCl solutions, and adding samples and standards to the broth at a constant volume to standardize the KCl molarity in the reaction vial.

Life history, floral development, and mating system in Clarkia xantiana (Onagraceae): do floral and whole-plant rates of development evolve independently?

Autogamously self-fertilizing taxa have evolved from outcrossing progenitors at least 12 times in the annual wildflower genus, Clarkia (Onagraceae). In C. xantiana, individuals of the selfing subspecies (ssp. parviflora) flower at an earlier age, produce successive flowers more rapidly, and produce flowers that complete their development more rapidly than their outcrossing counterparts (ssp. xantiana). Two hypotheses have been proposed to explain the joint evolution of these whole-plant and individual floral traits. The accelerated life cycle hypothesis proposes that selection favoring a short life cycle in environments with short growing seasons (such as those typically occupied by parviflora) has independently favored genotypes with early reproduction, synchronous flower production, and rapidly developing, self-fertilizing flowers. The correlated response to selection hypothesis similarly proposes that selection in environments with short growing seasons favors early reproduction, but that rapid floral development and increased selfing evolve as correlated responses to selection due to genetic linkage (or pleiotropy) affecting both whole-plant and floral development. We conducted a greenhouse experiment using maternal families from two field populations of each subspecies to examine covariation between floral and whole-plant traits within and among populations to seek support for either of these hypotheses. Our results are consistent with the accelerated life cycle hypothesis but not with the correlated response to selection hypothesis.

Unexpected findings in trauma patients dying in the intensive care unit: results of 153 consecutive autopsies.

BACKGROUND: The true incidence of missed injuries in trauma-related deaths is unknown, because in only about 60% of injury-related deaths nationwide is an autopsy performed. Few studies have documented the frequency of missed diagnoses leading to deaths specifically in the trauma ICU population. We attempted to evaluate the incidence and nature of missed injuries and complications in trauma- and burn-related deaths in our ICU given an autopsy rate of close to 100%. STUDY DESIGN: The medical records of all trauma- and burn-related deaths in the ICU over a 2-year period were reviewed retrospectively. Missed diagnoses were classified as class 1: major diagnosis that if recognized and treated appropriately might have changed outcomes; class II: major diagnosis that if recognized and treated appropriately would not have changed outcomes; and class III: minor diagnosis. RESULTS: Complete antemortem records were available for 158 patients, of which 153 (97%) underwent autopsy. Mean age was 50 years, and 72% were males. Mean ICU stay was 10 15 days. Four (3%) patients had class I missed diagnoses: bowel infarction, meningitis, retroperitoneal abscess, and bleeding gastric ulcer. Twenty-five (16%) patients had class II diagnoses, and 12 (8%) patients had class III diagnoses. Overall, 81% of 153 patients had either class III diagnoses or no missed injuries or complications. Pneumonia was the most common missed diagnosis. CONCLUSIONS: With an autopsy rate of 97%, 3% of deaths bad missed major diagnoses that might have affected outcomes if recognized antemortem. Autopsy findings can still provide valuable feedback in Improving the quality of care of critically ill trauma patients.