424 research outputs found
Saltmarsh plants, but not fertilizer, facilitate invertebrate recolonization after an oil spill
Foundation species contribute to the recovery of animal communities from disturbance by engineering, by improving habitat quality, and by regulating food availability. In a salt marsh impacted by the Deepwater Horizon oil spill, we tested the hypothesis that nutrient subsidies would enhance the positive effects of the foundation species Spartina alterniflora on the initial recolonization of benthic invertebrate communities (e.g., copepods, annelids, nematodes) by augmenting food (i.e., microalgae) availability. After two months, plantings of S.alterniflora significantly elevated the densities of the polychaete Capitella capitata, meiofauna-sized annelids, and total macroinfauna over unplanted plots. After 7months, the significant effect of plantings persisted for meiofauna-sized annelids, but not for C.capitata and total macroinfauna. Plantings had no effect on copepods (including Nannopus palustris, the dominant species), nematodes, or microalgal biomass for either month. Nutrient additions did not influence any taxon, despite initial increases in benthic microalgal biomass after 2months. We hypothesize that the structural effects of plants were important to early colonization, possibly by facilitating larval settlement or ameliorating temperature and desiccation stress. Our results emphasize the importance of re-establishing foundation species in oil-impacted sites to enhance recolonization of saltmarsh annelids, but suggest that recolonization is not promoted by the addition of nutrients
Condensate and superfluid fractions for varying interactions and temperature
A system with Bose-Einstein condensate is considered in the frame of the
self-consistent mean-field approximation, which is conserving, gapless, and
applicable for arbitrary interaction strengths and temperatures. The main
attention is paid to the thorough analysis of the condensate and superfluid
fractions in a wide region of interaction strengths and for all temperatures
between zero and the critical point T_c. The normal and anomalous averages are
shown to be of the same order for almost all interactions and temperatures,
except the close vicinity of T_c. But even in the vicinity of the critical
temperature, the anomalous average cannot be neglected, since only in the
presence of the latter the phase transition at T_c becomes of second order, as
it should be. Increasing temperature influences the condensate and superfluid
fractions in a similar way, by diminishing them. But their behavior with
respect to the interaction strength is very different. For all temperatures,
the superfluid fraction is larger than the condensate fraction. These coincide
only at T_c or under zero interactions. For asymptotically strong interactions,
the condensate is almost completely depleted, even at low temperatures, while
the superfluid fraction can be close to one.Comment: Latex file, 22 pages, 5 figure
Why do physicians prescribe dialysis? A prospective questionnaire study
Funding Information: This study was supported by an unrestricted grant 14CECPDEU1001 from Baxter Healthcare International. Baxter Novum is the result of a grant from Baxter Healthcare Corporation to Division of Renal Medicine and Baxter Novum, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, to support research activities at Karolinska Institutet to promote the understanding and treatment of renal disease. Bengt Lindholm is employed by Baxter Healthcare Corporation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This does not alter our adherence to PLOS ONE policies on sharing data and materials. Publisher Copyright: © 2017 Heaf et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.Introduction.The incidence of unplanned dialysis initiation (DI) with consequent increased comorbidity, mortality and reduced modality choice remains high, but the optimal timing of dialysis initiation (DI) remains controversial, and there is a lack of studies of specific reasons for DI. We investigated why and when physicians prescribe dialysis and hypothesized that physician motivation for DI is an independent factor which may have clinical consequences. Methods In the Peridialysis study, an ongoing multicenter prospective study assessing the causes and timing of DI and consequences of unplanned dialysis, physicians in 11 hospitals were asked to describe their primary, secondary and further reasons for prescribing DI. The stated reasons for DI were analyzed in relation to clinical and biochemical data at DI, and characteristics of physicians. Results In 446 patients (median age 67 years; 38% females; diabetes 25.6%), DI was prescribed by 84 doctors who stated 23 different primary reasons for DI. The primary indication was clinical in 63% and biochemical in 37%; 23% started for life-threatening conditions. Reduced renal function accounted for only 19% of primary reasons for DI but was a primary or contributing reason in 69%. The eGFR at DI was 7.2 ±3.4 ml/min/1.73 m2, but varied according to comorbidity and cause of DI. Patients with cachexia, anorexia and pulmonary stasis (34% with heart failure) had the highest eGFR (8.2–9.8 ml/min/1.73 m2), and those with edema, “low GFR”, and acidosis, the lowest (4.6–6.1 ml/min/1.73 m2). Patients with multiple comorbidity including diabetes started at a high eGFR (8.7 ml/min/1.73 m2). Physician experience played a role in dialysis prescription. Non-specialists were more likely to prescribe dialysis for life-threatening conditions, while older and more experienced physicians were more likely to start dialysis for clinical reasons, and at a lower eGFR. Female doctors started dialysis at a higher eGFR than males (8.0 vs. 7.1 ml/min/1.73 m2). Conclusions DI was prescribed mainly based on clinical reasons in accordance with current recommendations while low renal function accounted for only 19% of primary reasons for DI. There are considerable differences in physicians´ stated motivations for DI, related to their age, clinical experience and interpretation of biochemical variables. These differences may be an independent factor in the clinical treatment of patients, with consequences for the risk of unplanned DI.publishersversionPeer reviewe
Infrared Absorption Investigations Confirm the Extraterrestrial Origin of Carbonado-Diamonds
The first complete infrared FTIR absorption spectra for carbonado-diamond
confirm the interstellar origin for the most enigmatic diamonds known as
carbonado. All previous attempts failed to measure the absorption of
carbonado-diamond in the most important IR-range of 1000-1300 cm-1 (10.00-7.69
micro-m.) because of silica inclusions. In our investigation, KBr pellets were
made from crushed silica-free carbonado-diamond and thin sections were also
prepared. The 100 to 1000 times brighter synchrotron infrared radiation permits
a greater spatial resolution. Inclusions and pore spaces were avoided and/or
sources of chemical contamination were removed. The FTIR spectra of
carbonado-diamond mostly depict the presence of single nitrogen impurities, and
hydrogen. The lack of identifiable nitrogen aggregates in the infrared spectra,
the presence of features related to hydrocarbon stretch bonds, and the
resemblance of the spectra to CVD and presolar diamonds indicate that
carbonado-diamonds formed in a hydrogen-rich interstellar environment. This is
consistent with carbonado-diamond being sintered and porous, with extremely
reduced metals, metal alloys, carbides and nitrides, light carbon isotopes,
surfaces with glassy melt-like patinas, deformation lamellae, and a complete
absence of primary, terrestrial mineral inclusions. The 2.6-3.8 billion year
old fragmented body was of asteroidal proportions
Pre-dialysis clinic attendance improves quality of life among hemodialysis patients
BACKGROUND: Although previous research has demonstrated that referral to pre-dialysis clinics is associated with favourable objective outcomes, the benefit of a pre-dialysis clinic from the perspective of patient-perceived subjective outcomes, such as quality of life (QOL), is less well defined. METHODS: A retrospective incident cohort study was conducted to determine if pre-dialysis clinic attendance was a predictor of better QOL scores measured within the first six months of hemodialysis (HD) initiation. Inclusion criteria were HD initiation from January 1 1998 to January 1 2000, diagnosis of chronic renal failure, and completion of the QOL questionnaire within six months of HD initiation. Patients receiving HD for less than four weeks were excluded. An incident cohort of 120 dialysis patients was identified, including 74 patients who attended at least one pre-dialysis clinic and 46 patients who did not. QOL was measured using the SF 36-Item Health Survey. Independent variables included age, sex, diabetes, pre-dialysis clinic attendance and length of attendance, history of ischemic heart disease, stroke, peripheral vascular disease, heart failure, malignancy, and chronic lung disease, residual creatinine clearance at dialysis initiation, and kt/v, albumin and hemoglobin at the time of QOL assessment. Bivariate and multivariate linear regression analyses were used to identify predictors of QOL scores. RESULTS: Multivariate analysis suggested that pre-dialysis clinic attendance was an independent predictor of higher QOL scores in four of eight health domains (physical function, p < 0.01; emotional role limitation, p = 0.01; social function, p = 0.01; and general health, p = 0.03), even after statistical adjustment for age, sex, residual renal function, kt/v, albumin, and co-morbid disease. Pre-dialysis clinic attendance was also an independent predictor of the physical component summary score (p = 0.03). CONCLUSIONS: We conclude that pre-dialysis clinic attendance favourably influences patient-perceived quality of life within six months of dialysis initiation
Global and exponential attractors for a Ginzburg-Landau model of superfluidity
The long-time behavior of the solutions for a non-isothermal model in
superfluidity is investigated. The model describes the transition between the
normal and the superfluid phase in liquid 4He by means of a non-linear
differential system, where the concentration of the superfluid phase satisfies
a non-isothermal Ginzburg-Landau equation. This system, which turns out to be
consistent with thermodynamical principles and whose well-posedness has been
recently proved, has been shown to admit a Lyapunov functional. This allows to
prove existence of the global attractor which consists of the unstable manifold
of the stationary solutions. Finally, by exploiting recent techniques of
semigroups theory, we prove the existence of an exponential attractor of finite
fractal dimension which contains the global attractor.Comment: 39 page
Reimbursement and economic factors influencing dialysis modality choice around the world
The worldwide incidence of kidney failure is on the rise and treatment is costly; thus, the global burden of illness is growing. Kidney failure patients require either a kidney transplant or dialysis to maintain life. This review focuses on the economics of dialysis. Alternative dialysis modalities are haemodialysis (HD) and peritoneal dialysis (PD). Important economic factors influencing dialysis modality selection include financing, reimbursement and resource availability. In general, where there is little or no facility or physician reimbursement or payment for PD, the share of PD is very low. Regarding resource availability, when centre HD capacity is high, there is an incentive to use that capacity rather than place patients on home dialysis. In certain countries, there is interest in revising the reimbursement structure to favour home-based therapies, including PD and home HD. Modality selection is influenced by employment status, with an association between being employed and PD as the modality choice. Cost drivers differ for PD and HD. PD is driven mainly by variable costs such as solutions and tubing, while HD is driven mainly by fixed costs of facility space and staff. Many cost comparisons of dialysis modalities have been conducted. A key factor to consider in reviewing cost comparisons is the perspective of the analysis because different costs are relevant for different perspectives. In developed countries, HD is generally more expensive than PD to the payer. Additional research is needed in the developing world before conclusive statements may be made regarding the relative costs of HD and PD
Supporting Spartina: Interdisciplinary Perspective Shows Spartina As A Distinct Solid Genus
In 2014, a DNA-based phylogenetic study confirming the paraphyly of the grass subtribe Sporobolinae proposed the creation of a large monophyletic genus Sporobolus, including (among others) species previously included in the genera Spartina, Calamovilfa, and Sporobolus. Spartina species have contributed substantially (and continue contributing) to our knowledge in multiple disciplines, including ecology, evolutionary biology, molecular biology, biogeography, experimental ecology, biological invasions, environmental management, restoration ecology, history, economics, and sociology. There is no rationale so compelling to subsume the name Spartina as a subgenus that could rival the striking, global iconic history and use of the name Spartina for over 200 yr. We do not agree with the subjective arguments underlying the proposal to change Spartina to Sporobolus. We understand the importance of both the objective phylogenetic insights and of the subjective formalized nomenclature and hope that by opening this debate we will encourage positive feedback that will strengthen taxonomic decisions with an interdisciplinary perspective. We consider that the strongly distinct, monophyletic clade Spartina should simply and efficiently be treated as the genus Spartina
Association of dialysis facility-level hemoglobin measurement and erythropoiesis-stimulating agent dose adjustment frequencies with dialysis facility-level hemoglobin variation: a retrospective analysis
<p>Abstract</p> <p>Background</p> <p>A key goal of anemia management in dialysis patients is to maintain patients' hemoglobin (Hb) levels consistently within a target range. Our aim in this study was to assess the association of facility-level practice patterns representing Hb measurement and erythropoiesis-stimulating agent (ESA) dose adjustment frequencies with facility-level Hb variation.</p> <p>Methods</p> <p>This was a retrospective observational database analysis of patients in dialysis facilities affiliated with large dialysis organizations as of July 01, 2006, covering a follow-up period from July 01, 2006 to June 30, 2009. A total of 2,763 facilities representing 436,442 unique patients were included. The predictors evaluated were facility-level Hb measurement and ESA dose adjustment frequencies, and the outcome measured was facility-level Hb variation.</p> <p>Results</p> <p>First to 99th percentile ranges for facility-level Hb measurement and ESA dose adjustment frequencies were approximately once per month to once per week and approximately once per 3 months to once per 3 weeks, respectively. Facility-level Hb measurement and ESA dose adjustment frequencies were inversely associated with Hb variation. Modeling results suggested that a more frequent Hb measurement (once per week rather than once per month) was associated with approximately 7% to 9% and 6% to 8% gains in the proportion of patients with Hb levels within a ±1 and ±2 g/dL range around the mean, respectively. Similarly, more frequent ESA dose adjustment (once per 2 weeks rather than once per 3 months) was associated with approximately 6% to 9% and 5% to 7% gains in the proportion of patients in these respective Hb ranges.</p> <p>Conclusions</p> <p>Frequent Hb measurements and timely ESA dose adjustments in dialysis patients are associated with lower facility-level Hb variation and an increase in proportion of patients within ±1 and ±2 g/dL ranges around the facility-level Hb mean.</p
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