1,408 research outputs found
Pole Inflation - Shift Symmetry and Universal Corrections
An appealing explanation for the Planck data is provided by inflationary
models with a singular non-canonical kinetic term: a Laurent expansion of the
kinetic function translates into a potential with a nearly shift-symmetric
plateau in canonical fields. The shift symmetry can be broken at large field
values by including higher-order poles, which need to be hierarchically
suppressed in order not to spoil the inflationary plateau. The herefrom
resulting corrections to the inflationary dynamics and predictions are shown to
be universal at lowest order and possibly to induce power loss at large angular
scales. At lowest order there are no corrections from a pole of just one order
higher and we argue that this phenomenon is related to the well-known extended
no-scale structure arising in string theory scenarios. Finally, we outline
which other corrections may arise from string loop effects.Comment: twocolumn, 9 pages, 1 figure; v2: clarifications and refs added, JHEP
layout, 19 page
Scalable Layer-2/Layer-3 Multistage Switching Architectures for Software Routers
Software routers are becoming an important alternative to proprietary and expensive network devices, because they exploit the economy of scale of the PC market and open-source software. When considering maximum performance in terms of throughput, PC-based routers suffer from limitations stemming from the single PC architecture, e.g., limited bus bandwidth, and high memory access latency. To overcome these limitations, in this paper we present a multistage architecture that combines a layer-2 load-balancer front-end and a layer-3 routing back-end, interconnected by standard Ethernet switches. Both the front-end and the back-end are implemented using standard PCs and open- source software. After describing the architecture, evaluation is performed on a lab test-bed, to show its scalability. While the proposed solution allows to increase performance of PC- based routers, it also allows to distribute packet manipulation functionalities, and to automatically recover from component failures
Detection Method for Liquids Using Near Infrared Spectra
A method for detecting the presence or absence of microorganisms in a liquid test sample is provided without need for withdrawing an aliquot or destroying the sample. The method comprises taking near-infrared spectra of the sample and comparing it visually or mathematically to the spectra of a standard, which may be the values of the spectra known to the operator or may be a standard sample that is provided and run side-by-side
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Prospective observational study of point-of-care creatinine in trauma.
Background:Patients with trauma are at risk for renal dysfunction from hypovolemia or urological injury. In austere environments, creatinine values are not available to guide resuscitation. A new portable device, the Stat Sensor Point-of-care (POC) Whole Blood Creatinine Analyzer, provides accurate results in <30 s and requires minimal training. This device has not been evaluated in trauma despite the theoretical benefit it provides. The purpose of this study is to determine the clinical impact of the POC device in trauma. Methods:40 patients with trauma were enrolled in a prospective observational study. One drop of blood was used for creatinine determination on the Statsensor POC device. POC creatinine results were compared to the laboratory. Turnaround time (TAT) for POC and laboratory methods was calculated as well as time elapsed to CT scan if applicable. Results:Patients (n=40) were enrolled between December 2014 and March 2015. POC creatinine values were similar to laboratory methods with a mean bias of 0.075±0.27 (p=0.08). Mean analytical TATs for the POC measurements were significantly faster than the laboratory method (11.6±10.0 min vs 78.1±27.9 min, n=40, p<0.0001). Mean elapsed time before arrival at the CT scanner was 52.9±34.2 min. Conclusions:The POC device reported similar creatinine values to the laboratory and provided significantly faster results. POC creatinine testing is a promising development for trauma practice in austere environments and workup of a subset of stable patients with trauma. Further study is warranted to determine clinical impact, both in hospital-based trauma and austere environments
Approaching Space Time Through Velocity in Doubly Special Relativity
We discuss the definition of velocity as dE/dp, where E,p are the energy and
momentum of a particle, in Doubly Special Relativity (DSR). If this definition
matches dx/dt appropriate for the space-time sector, then space-time can in
principle be built consistently with the existence of an invariant length
scale. We show that, within different possible velocity definitions, a
space-time compatible with momentum-space DSR principles can not be derived.Comment: 11 pages, no figures, minor changes, references added, final version
to appear in PR
Effects of mindfulness-based cognitive therapy on mental disorders: a systematic review and meta-analysis of randomised controlled trials.
OBJECTIVE: Mindfulness-based cognitive therapy (MBCT) is a programme developed to prevent depression relapse, but has been applied for other disorders. Our objective was to systematically review and meta-analyse the evidence on the effectiveness and safety of MBCT for the treatment of mental disorders. METHODS: Searches were completed in CENTRAL, MEDLINE, EMBASE, LILACS, PsychINFO, and PsycEXTRA in March 2011 using a search strategy with the terms 'mindfulness-based cognitive therapy', 'mindfulness', and 'randomised controlled trials' without time restrictions. Selection criteria of having a randomised controlled trial design, including patients diagnosed with mental disorders, using MBCT according to the authors who developed MBCT and providing outcomes that included changes in mental health were used to assess 608 reports. Two reviewers applied the pre-determined selection criteria and extracted the data into structured tables. Meta-analyses and sensitivity analyses were completed. RESULTS: Eleven studies were included. Most of them evaluated depression and compared additive MBCT against usual treatment. After 1 year of follow-up MBCT reduced the rate of relapse in patients with three or more previous episodes of depression by 40% (5 studies, relative risk [95% confidence interval]: 0.61 [0.48, 0.79]). Other meta-analysed outcomes were depression and anxiety, both with significant results but unstable in sensitivity analyses. Methodological quality of the reports was moderate. CONCLUSION: Based on this review and meta-analyses, MBCT is an effective intervention for patients with three or more previous episodes of major depression
Pharmaceutical vehicles for vaginal and rectal administration of anti-hiv microbicide nanosystems
Prevention strategies play a key role in the fight against HIV/AIDS. Vaginal and rectal microbicides hold great promise in tackling sexual transmission of HIV-1, but effective and safe products are yet to be approved and made available to those in need. While most efforts have been placed in finding and testing suitable active drug candidates to be used in microbicide development, the last decade also saw considerable advances in the design of adequate carrier systems and formulations that could lead to products presenting enhanced performance in protecting from infection. One strategy demonstrating great potential encompasses the use of nanosystems, either with intrinsic antiviral activity or acting as carriers for promising microbicide drug candidates. Polymeric nanoparticles, in particular, have been shown to be able to enhance mucosal distribution and retention of promising antiretroviral compounds. One important aspect in the development of nanotechnology-based microbicides relates to the design of pharmaceutical vehicles that allow not only convenient vaginal and/or rectal administration, but also preserve or even enhance the performance of nanosystems. In this manuscript, we revise relevant work concerning the selection of vaginal/rectal dosage forms and vehicle formulation development for the administration of microbicide nanosystems. We also pinpoint major gaps in the field and provide pertinent hints for future work.This work was supported by Programa Gilead GÉNESE, Gilead Portugal (refs. PGG/046/2015 and PGG/002/2016). This article is a result of the project NORTE-01-0145-FEDER-000012, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work was financed by FEDER-Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020-Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT-Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274), and also Partnership Agreement PT2020 UID/QUI/50006/2013-POCI/01/0145/FEDER/007265. J.G. gratefully acknowledges FCT for financial support (SFRH/BD/140271/2018 scholarship)
Short-term Effects of Gamma Ray Bursts on Earth
The aim of the present work is to study the potential short-term atmospheric
and biospheric influence of Gamma Ray Bursts on the Earth. We focus in the
ultraviolet flash at the planet's surface, which occurs as a result of the
retransmission of the radiation through the atmosphere. This would be
the only important short-term effect on life. We mostly consider Archean and
Proterozoic eons, and for completeness we also comment on the Phanerozoic.
Therefore, in our study we consider atmospheres with oxygen levels ranging from
to 1% of the present atmospheric level, representing different
moments in the oxygen rise history. Ecological consequences and some strategies
to estimate their importance are outlined.Comment: 13 pp., to appear in Astrophysics and Space Scienc
El urbanismo como instrumento de poder. Las ciudades canarias del siglo XIX
El análisis de las ciudades no se debe fundamentar, exclusivamente, en la valoración formal, espacial y semántica de sus edificios. Como muestra este artículo, al analizar las ciudades canarias del siglo XIX, se observa que convergen motivos económicos y políticos, aspectos que definieron la nueva imagen urbana, como la División Municipal (1833) Estas ciudades canarias fueron los instrumentos que la burguesía utilizó para legitimar su riqueza, prestigio y poder.The analysis of cities should not be based exclusively on the formal, spatial and semantic valuation of their buildings. As this article shows, when analyzing nineteenth century Canarian cities, it is observed that economic and political reasons converge, aspects that defined the new urban image, such as the Municipal Division (1833) These Canarian cities were the instruments that the bourgeoisie used to legitimize its wealth, prestige and power.peerReviewe
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