361 research outputs found
Discrete charging of metallic grains: Statistics of addition spectra
We analyze the statistics of electrostatic energies (and their differences)
for a quantum dot system composed of a finite number of electron islands
(metallic grains) with random capacitance-inductance matrix , for which the
total charge is discrete, (where is the charge of an electron and
is an integer). The analysis is based on a generalized charging model,
where the electrons are distributed among the grains such that the
electrostatic energy E(N) is minimal. Its second difference (inverse
compressibility) represents the spacing between
adjacent Coulomb blockade peaks appearing when the conductance of the quantum
dot is plotted against gate voltage. The statistics of this quantity has been
the focus of experimental and theoretical investigations during the last two
decades. We provide an algorithm for calculating the distribution function
corresponding to and show that this function is piecewise
polynomial.Comment: 21 pages, no figures, mathematical nomenclature (except for Abstract
and Introduction
Hepatitis C services at harm reduction centres in the European Union: a 28-country survey
Background: In the context of the WHO’s 2016 Viral Hepatitis Strategy and the introduction of treatment that
can cure more than 95% of cases with hepatitis C virus (HCV) infection, the European Joint Action on HIV
and Co-infection Prevention and Harm Reduction (HA-REACT) undertook a study in the member states of the
European Union (EU). It aimed to determine service providers’ understanding of the current services in their
respective countries and the barriers experienced by PWID in accessing HCV testing, care and treatment
services in their country.
Methods: In 2017, 38 purposively selected harm reduction service providers completed a 26-item Englishlanguage online survey addressing the availability, accessibility and funding of HCV services at harm reduction
centres. HCV-related data and reported findings were extracted by country or by responding organization.
Results: Responses were received from all EU member states. Respondents from 23 countries reported that
HCV tests are offered by harm reduction services in their countries, and eight countries reported that
addiction specialists in their countries are able to prescribe HCV therapy. Almost half of the respondents
(45%) said that their respective organizations had established referral systems with centres providing HCV
treatment.
Conclusions: Not all EU member states have harm reduction services that provide HCV tests, and many do
not have established referral systems with treatment providers. Moreover, the inability of addiction specialists
to prescribe HCV treatment points to missed opportunities to make treatment more accessible. Further,
discrepancies were noted between the available HCV services and stakeholders’ knowledge about their
availability
Health Outcomes for Clients of Needle and Syringe Programs in Prisons
High levels of drug dependence have been observed in the
prison population globally, and the sharing of injecting drug
equipment in prisons has contributed to higher prevalence of
bloodborne diseases in prisoners than in the general population.
Few prison needle and syringe programs (PNSPs) exist. We
conducted a systematic review to assess evidence regarding
health outcomes of PNSPs. We searched peer-reviewed databases
for data relating to needle and syringe programs in prisons. The
search methodology was conducted in accordance with accepted
guidelines. Five studies met review inclusion criteria, and all
presented evidence associating PNSPs with one or more health
benefits, but the strength of the evidence was low. The outcomes
for which the studies collectively demonstrated the strongest
evidence were prevention of human immunodeficiency virus and
viral hepatitis. Few negative consequences from PNSPs were
observed, consistent with previous evidence assessments. More
research is needed on PNSP effectiveness, and innovative study
designs are needed to overcome methodological limitations of
previous research. Until stronger evidence becomes available,
policymakers are urged to recognize that not implementing PNSPs
has the potential to cause considerable harm, in light of what
is currently known about the risks and benefits of needle and
syringe programs and PNSPs and about the high prevalence of
human immunodeficiency virus and viral hepatitis in prisons
Early disruptions to syringe services programs during the Russian invasion of Ukraine
IntroductionThe widespread HIV epidemic in Ukraine is concentrated among people who inject drugs (PWID), making access to sterile injection paraphernalia (SIP) like sterile needles and syringes a critical method of HIV/AIDS prevention; however, the Russian invasion has threatened to disrupt the operations of syringe services programs (SSPs), creating a risk of HIV outbreaks among PWID.MethodsWe conducted 10 semi-structured interviews with outreach workers from SSPs. Interviews were purposively sampled to cover three prototypic regions of Ukraine: temporarily Russian-controlled, frontline, and destination. Qualitative results from interviews were then compared against a standardized, nationwide harm reduction database.ResultsWe found that the Russian invasion triggered both supply and demand challenges for SSPs. Demand increased for all regions due to client transitions from pharmacies that closed to SSPs, increases in illicit drug use, greater client openness to NGO support, and displacement of clients to destination regions. Supply decreased for all areas (except for remote destination regions) due to battle-related barriers like curfews, roadblocks, and Internet disruptions; diminished deliveries of SIP and funding; and staff displacement. Time series plots of the number of unique clients accessing harm reduction services showed that an initial decrease in service provision occurred at the start of the war but that most regions recovered within several months except for Russian-controlled regions, which continued to provide services to fewer clients relative to previous years.ConclusionTo ensure continued scale-up of SIP and other HIV prevention services, the SyrEx database should be leveraged to serve as a streamlined harm reduction locator that can inform workers and clients of open site locations and other pertinent information
Cell-Free DNA and Active Rejection in Kidney Allografts
Histologic analysis of the allograft biopsy specimen is the standard method used to differentiate rejection from other injury in kidney transplants. Donor-derived cell-free DNA (dd-cfDNA) is a noninvasive test of allograft injury that may enable more frequent, quantitative, and safer assessment of allograft rejection and injury status. To investigate this possibility, we prospectively collected blood specimens at scheduled intervals and at the time of clinically indicated biopsies. In 102 kidney recipients, we measured plasma levels of dd-cfDNA and correlated the levels with allograft rejection status ascertained by histology in 107 biopsy specimens. The dd-cfDNA level discriminated between biopsy specimens showing any rejection (T cell-mediated rejection or antibody-mediated rejection [ABMR]) and controls (no rejection histologically), P1% indicate a probability of active rejection
Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt{s}=1.96 TeV using Lepton + Jets Events with Secondary Vertex b-tagging
We present a measurement of the ttbar production cross section using events
with one charged lepton and jets from ppbar collisions at a center-of-mass
energy of 1.96 TeV. In these events, heavy flavor quarks from top quark decay
are identified with a secondary vertex tagging algorithm. From 162 pb-1 of data
collected by the Collider Detector at Fermilab, a total of 48 candidate events
are selected, where 13.5 +- 1.8 events are expected from background
contributions. We measure a ttbar production cross section of 5.6^{+1.2}_{-1.1}
(stat.) ^{+0.9}_{0.6} (syst.) pb.Comment: 28 pages, 20 figures. Published in Physical Review
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Mesopontine rostromedial tegmental nucleus neurons projecting to the dorsal raphe and pedunculopontine tegmental nucleus: psychostimulant-elicited Fos expression and collateralization
The mesopontine rostromedial tegmental nucleus (RMTg) is a GABAergic structure in the ventral midbrain and rostral pons that, when activated, inhibits dopaminergic neurons in the ventral tegmental area and substantia nigra compacta. Additional strong outputs from the RMTg to the pedunculopontine tegmental nucleus pars dissipata, dorsal raphe nucleus, and the pontomedullary gigantocellular reticular formation were identified by anterograde tracing. RMTg neurons projecting to the ventral tegmental area express the immediate early gene Fos upon psychostimulant administration. The present study was undertaken to determine if neurons in the RMTg that project to the additional structures listed above also express Fos upon psychostimulant administration and, if so, whether single neurons in the RMTg project to more than one of these structures. We found that about 50% of RMTg neurons exhibiting retrograde labeling after injections of retrograde tracer in the dorsal raphe or pars dissipata of the pedunculopontine tegmental nucleus express Fos after acute methamphetamine exposure. Also, we observed that a significant number of RMTg neurons project both to the ventral tegmental area and one of these structures. In contrast, methamphetamine-elicited Fos expression was not observed in RMTg neurons labeled with retrograde tracer following injections into the pontomedullary reticular formation. The findings suggest that the RMTg is an integrative modulator of multiple rostrally projecting structures
Nomenclature for kidney function and disease: report of a Kidney Disease:Improving Global Outcomes (KDIGO) Consensus Conference
The worldwide burden of kidney disease is rising, but public awareness remains limited, underscoring the need for more effective communication by stakeholders in the kidney health community. Despite this need for clarity, the nomenclature for describing kidney function and disease lacks uniformity. In June 2019, Kidney Disease: Improving Global Outcomes (KDIGO) convened a Consensus Conference with the goal of standardizing and refining the nomenclature used in the English language to describe kidney function and disease, and of developing a glossary that could be used in scientific publications. Guiding principles of the conference were that the revised nomenclature should be patient-centered, precise, and consistent with nomenclature used in the KDIGO guidelines. Conference attendees reached general consensus on the following recommendations: (i) to use "kidney" rather than "renal" or "nephro-" when referring to kidney disease and kidney function; (ii) to use "kidney failure" with appropriate descriptions of presence or absence of symptoms, signs, and treatment, rather than "end-stage kidney disease"; (iii) to use the KDIGO definition and classification of acute kidney diseases and disorders (AKD) and acute kidney injury (AKI), rather than alternative descriptions, to define and classify severity of AKD and AKI; (iv) to use the KDIGO definition and classification of chronic kidney disease (CKD) rather than alternative descriptions to define and classify severity of CKD; and (v) to use specific kidney measures, such as albuminuria or decreased glomerular filtration rate (GFR), rather than "abnormal" or "reduced" kidney function to describe alterations in kidney structure and function. A proposed 5-part glossary contains specific items for which there was general agreement. Conference attendees acknowledged limitations of the recommendations and glossary, but they considered standardization of scientific nomenclature to be essential for improving communication
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