The Equilibrium Phosphorus Concentration (EPC
0) of river bed sediments has been measured for a wide range of agricultural subcatchments and main river sites across two major eutrophic river basins: ...the Hampshire Avon and Herefordshire Wye catchments, to examine whether bed sediments are acting as sources or sinks of soluble reactive phosphorus (SRP) under low flows and times of greatest eutrophication risk. A conceptual reach-based model of interactions between bed sediment and river water has been used to estimate relative differences in bed-sediment SRP flux transfers. In this model, processes of SRP uptake and release are assumed to occur within an operationally defined 0.1
m river water ‘boundary layer’ and the uptake and release of SRP is assumed to be driven by a differential between the EPC
0 of the sediment and SRP concentration in the boundary layer. Most of the river monitoring sites in the Wye and Avon catchments had elevated SRP and boron (B) concentrations in the water column at low flows, linked to sewage effluent discharges. At these sites, bed sediments consistently acted as net sinks for SRP, demonstrating the role of bed sediments in riverine ‘self-cleansing’ mechanisms. In contrast, bed sediments were found to act as net sources of SRP under three circumstances: (i) where there was minimal sewage influence (in headwater streams of the Avon), (ii) where sewage inputs were subject to large hydrological dilution by water of low SRP concentration (in the main River Wye), (iii) where EPC
0 values were relatively high, as a result of deposition of particulates with high exchangeable P concentrations from diffuse sources or from effluents (immediately downstream of sewage treatment works (STWs)). Under baseflow conditions, high SRP concentrations from sewage effluent in the tributaries appear to ‘swamp out’ any potential release of SRP from the bed sediments. For rivers that are subject to effluent P-stripping, reductions in SRP in the overlying water could potentially result in changes to the in-stream P-cycling mechanisms, with bed sediments possibly switching from net sinks to net sources of SRP. This feature is of potential importance in relation to environmental management and phosphorus mitigation operations.
Although CP violation in the B meson system has been well established by the B factories, there has been no direct observation of time-reversal violation. The decays of entangled neutral B mesons ...into definite flavor states (B(0) or B(0)), and J/ψK(L)(0) or ccK(S)(0) final states (referred to as B(+) or B(-)), allow comparisons between the probabilities of four pairs of T-conjugated transitions, for example, B(0) → B(-) and B(-) → B(0), as a function of the time difference between the two B decays. Using 468 × 10(6) BB pairs produced in Υ(4S) decays collected by the BABAR detector at SLAC, we measure T-violating parameters in the time evolution of neutral B mesons, yielding ΔS(T)(+) = -1.37 ± 0.14(stat) ± 0.06(syst) and ΔS(T)(-) = 1.17 ± 0.18(stat) ± 0.11(syst). These nonzero results represent the first direct observation of T violation through the exchange of initial and final states in transitions that can only be connected by a T-symmetry transformation.
The possible effects of changing climate on a southern and a north-eastern English river (the Thames and the Yorkshire Ouse, respectively) were examined in relation to water and ecological quality ...throughout the food web. The CLASSIC hydrological model, driven by output from the Hadley Centre climate model (HadCM3), based on IPCC low and high CO
2 emission scenarios for 2080 were used as the basis for the analysis. Compared to current conditions, the CLASSIC model predicted lower flows for both rivers, in all seasons except winter. Such an outcome would lead to longer residence times (by up to a month in the Thames), with nutrient, organic and biological contaminant concentrations elevated by 70–100% pro-rata, assuming sewage treatment effectiveness remains unchanged. Greater opportunities for phytoplankton growth will arise, and this may be significant in the Thames. Warmer winters and milder springs will favour riverine birds and increase the recruitment of many coarse fish species. However, warm, slow-flowing, shallower water would increase the incidence of fish diseases. These changing conditions would make southern UK rivers in general a less favourable habitat for some species of fish, such as the Atlantic salmon (
Salmo salar). Accidental or deliberate, introductions of alien macrophytes and fish may change the range of species in the rivers. In some areas, it is possible that a concurrence of different pressures may give rise to the temporary loss of ecosystem services, such as providing acceptable quality water for humans and industry. An increasing demand for water in southern England due to an expanding population, a possibly reduced flow due to climate change, together with the Water Framework Directive obligation to maintain water quality, will put extreme pressure on river ecosystems, such as the Thames.
A major feature of Alzheimer's disease is the accumulation of amyloid-β peptide (Aβ) in the brain both in the form of plaques in the cerebral cortex and in blood vessel as cerebral amyloid angiopathy ...(CAA). Experimental models and human clinical trials have shown that accumulation of Aβ plaques can be reversed by immunotherapy. In this study, we hypothesized that Aβ in plaques is solubilized by antibodies generated by immunization and drains via the perivascular pathway, detectable as an increase in cerebrovascular Aβ. We have performed a follow up study of Alzheimer's disease patients immunized against Aβ42. Neuropathological examination was performed on nine patients who died between four months and five years after their first immunization. Immunostaining for Aβ40 and Aβ42 was quantified and compared with that in unimmunized Alzheimer's disease controls (n = 11). Overall, compared with these controls, the group of immunized patients had approximately 14 times as many blood vessels containing Aβ42 in the cerebral cortex (P<0.001) and seven times more in the leptomeninges (P = 0.013); among the affected blood vessels in the immunized cases, most of them had full thickness and full circumference involvement of the vessel wall in the cortex (P = 0.001), and in the leptomeninges (P = 0.015). There was also a significantly higher level of cerebrovascular Aβ40 in the immunized cases than in the unimmunized cases (cortex: P = 0.009 and leptomeninges: P = 0.002). In addition, the immunized patients showed a higher density of cortical microhaemorrhages and microvascular lesions than the unimmunized controls, though none had major CAA-related intracerebral haemorrhages. The changes in cerebral vascular Aβ load did not appear to substantially influence the structural proteins of the blood vessels. Unlike most of the immunized patients, two of the longest survivors, four to five years after first immunization, had virtually complete absence of both plaques and CAA, raising the possibility that, given time, Aβ is eventually cleared from the cerebral vasculature. The findings are consistent with the hypothesis that Aβ immunization results in solubilization of plaque Aβ42 which, at least in part, exits the brain via the perivascular pathway, causing a transient increase in the severity of CAA. The extent to which these vascular alterations following Aβ immunization in Alzheimer's disease are reflected in changes in cognitive function remains to be determined.
We present a search for a neutral, long-lived particle L that is produced in e+ e- collisions and decays at a significant distance from the e+ e- interaction point into various flavor combinations of ...two oppositely charged tracks. The analysis uses an e+ e- data sample with a luminosity of 489.1 fb(-1) collected by the BABAR detector at the ϒ(4S), ϒ(3S), and ϒ(2S) resonances and just below the ϒ(4S). Fitting the two-track mass distribution in search of a signal peak, we do not observe a significant signal, and set 90% confidence level upper limits on the product of the L production cross section, branching fraction, and reconstruction efficiency for six possible two-body L decay modes as a function of the L mass. The efficiency is given for each final state as a function of the mass, lifetime, and transverse momentum of the candidate, allowing application of the upper limits to any production model. In addition, upper limits are provided on the branching fraction B(B→XsL), where Xs is a strange hadronic system.
We report the identification of metastable isomeric states of
228
Ac at 6.28 keV, 6.67 keV and 20.19 keV, with lifetimes of an order of 100 ns. These states are produced by the
β
-decay of
228
Ra, a ...component of the
232
Th decay chain, with
β
Q-values of 39.52 keV, 39.13 keV and 25.61 keV, respectively. Due to the low Q-value of
228
Ra as well as the relative abundance of
232
Th and their progeny in low background experiments, these observations potentially impact the low-energy background modeling of dark matter search experiments.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
ACC/AHA Task Force Members Glenn N. Levine, MD, FACC, FAHA, Chair Patrick T. O’Gara, MD, MACC, FAHA, Chair-Elect Jonathan L. Halperin, MD, FACC, FAHA, Immediate Past Chair¶ Sana M. Al-Khatib, MD, ...MHS, FACC, FAHA Joshua A. Beckman, MD, MS, FAHA Kim K. Birtcher, MS, PharmD, AACC Biykem Bozkurt, MD, PhD, FACC, FAHA¶ Ralph G. Brindis, MD, MPH, MACC¶ Joaquin E. Cigarroa, MD, FACC Anita Deswal, MD, MPH, FACC, FAHA Lesley H. Curtis, PhD, FAHA¶ Lee A. Fleisher, MD, FACC, FAHA Federico Gentile, MD, FACC Samuel Gidding, MD, FAHA¶ Zachary D. Goldberger, MD, MS, FACC, FAHA Mark A. Hlatky, MD, FACC, FAHA John Ikonomidis, MD, PhD, FAHA José A. Joglar, MD, FACC, FAHA Laura Mauri, MD, MSc, FAHA Barbara Riegel, PhD, RN, FAHA Susan J. Pressler, PhD, RN, FAHA¶ Duminda N. Wijeysundera, MD, PhD¶Former Task Force member; current member during the writing effort.Table of Contents Preamblee93 Introductione95 1.1.Methodology and Evidence Reviewe95 1.2.Organization of the Writing Committeee95 1.3.Document Review and Approvale95 1.4.Scope of the Guidelinee97 1.5.Abbreviationse99 2. Evidence Gaps and Future Research Needse182 Appendix 1 Author Relationships With Industry and Other Entities (Relevant)e214 Appendix 2 Reviewer Relationships With Industry and Other Entities (Comprehensive)e216 Preamble Since 1980, the American College of Cardiology (ACC) and American Heart Association (AHA) have translated scientific evidence into clinical practice guidelines with recommendations to improve cardiovascular health. Adherence to recommendations can be enhanced by shared decision-making between healthcare providers and patients, with patient engagement in selecting interventions based on individual values, preferences, and associated conditions and comorbidities.Methodology and Modernization The ACC/AHA Task Force on Clinical Practice Guidelines (Task Force) continuously reviews, updates, and modifies guideline methodology on the basis of published standards from organizations including the Institute of Medicine (P-1,P-2) and on the basis of internal reevaluation. Publication of new, potentially practice-changing study results that are relevant to an existing or new medication, device, or management strategy will prompt evaluation by the Task Force, in consultation with the relevant guideline writing committee, to determine whether a focused update should be commissioned.
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