1,427 research outputs found
Evaluación de tres modelos para estimar la variación diurna y diaria de la radiación neta en un cultivo de tomates (Licopersicon esculentum Mill)
Resumen (Spanish, English)36 p.Se desarrolló un estudio para evaluar tres modelos que permiten estimar la radiación neta (Rn) en intervalos de tiempo de veinte minutos y cada 24 horas. Para ello se instaló un sistema meteorológico automático que midió variables climáticas (radiación global, radiación neta, temperatura del aire, humedad relativa y presión de vapor) en la parte central de un cultivo de tomate ubicado en la Estación Experimental Panguilemo (35º23’13” latitud sur, 71º40’42” longitud oeste y a una altura de 110,5 m sobre el nivel del mar). Los resultados de este estudio indicaron que el mejor modelo evaluado fue capaz de estimar la variación diurna de la Rn en intervalos de tiempo de 20 minutos con una desviación estándar del error (DEE) de 32 Wm-2 y un error absoluto (Ea) de 3,4%. Por otro lado, la Rn diaria estimada presentó una DEE y un Ea de 0,04 MJm-2d-1 y 3,4%, respectivamente. Los mayores errores entre los valores de radiación neta observada (RnO) y estimada (RnE) fueron asociados a la estimación de la emisividad del aire
Holographic Renormalization Group with Fermions and Form Fields
We find the Holographic Renormalization Group equations for the holographic
duals of generic gravity theories coupled to form fields and spin-1/2 fermions.
Using Hamilton-Jacobi theory we discuss the structure of Ward identities,
anomalies, and the recursive equations for determining the divergent terms of
the generating functional. In particular, the Ward identity associated to
diffeomorphism invariance contains an anomalous contribution that, however, can
be solved either by a suitable counter term or by imposing a condition on the
boundary fields. Consistency conditions for the existence of the dual arise, if
one requires that a Callan-Symanzik type equation follows from the Hamiltonian
constraint. Under mild assumptions we are able to find a class of solutions to
the constraint equations. The structure of the fermionic phase space and
constraints is treated extensively for any dimension and signature.Comment: 37 pages, LaTeX; v2: Minor changes, references added; v3: End of Sec.
5 and the Appendix C removed. Final version published in Nuclear Physics
HIV diagnosis in Brazil: the impact of the COVID-19 pandemic
Letter to the editor
Omeprazole Increases the Efficacy of Acyclovir Against Herpes Simplex Virus Type 1 and 2
Omeprazole was shown to improve the anti-cancer effects of the nucleoside analogue 5-fluorouracil. Here, we combined omeprazole with the antiviral nucleoside analogues ribavirin and acyclovir. Omeprazole did not affect the antiviral effects of ribavirin in non-toxic concentrations up to 80 μg/mL but increased the acyclovir-mediated effects on herpes simplex virus 1 and 2 (HSV-1 and -2) replication in a dose-dependent manner. Omeprazole alone reduced HSV-1 and -2 titers [but not HSV-induced formation of cytopathogenic effects (CPE)] at concentrations ≥40 μg/mL. However, it exerted substantially stronger effects on acyclovir activity and also increased acyclovir activity at lower concentrations that did not directly interfere with HSV replication. Omeprazole 80 μg/mL caused a 10.8-fold (Vero cells) and 47.7-fold (HaCaT cells) decrease of the acyclovir concentrations that reduced HSV-1-induced CPE formation by 50% (IC50). In HSV-2-infected cells, omeprazole 80 μg/mL reduced the acyclovir IC50 by 7.3- (Vero cells) and 12.9-fold (HaCaT cells). In HaCaT cells, omeprazole 80 μg/mL reduced the HSV-1 titer in the presence of acyclovir 1 μg/mL by 1.6 × 105-fold and the HSV-2 titer in the presence of acyclovir 2 μg/mL by 9.2 × 103-fold. The proton pump inhibitors pantoprazole, rabeprazole, lansoprazole, and dexlansoprazole increased the antiviral effects of acyclovir in a similar fashion as omeprazole, indicating this to be a drug class effect. In conclusion, proton pump inhibitors increase the anti-HSV activity of acyclovir and are candidates for antiviral therapies in combination with acyclovir, in particular for topical preparations for the treatment of immunocompromised individuals who are more likely to suffer from severe complications
Astrophysically Triggered Searches for Gravitational Waves: Status and Prospects
In gravitational-wave detection, special emphasis is put onto searches that
focus on cosmic events detected by other types of astrophysical observatories.
The astrophysical triggers, e.g. from gamma-ray and X-ray satellites, optical
telescopes and neutrino observatories, provide a trigger time for analyzing
gravitational wave data coincident with the event. In certain cases the
expected frequency range, source energetics, directional and progenitor
information is also available. Beyond allowing the recognition of gravitational
waveforms with amplitudes closer to the noise floor of the detector, these
triggered searches should also lead to rich science results even before the
onset of Advanced LIGO. In this paper we provide a broad review of LIGO's
astrophysically triggered searches and the sources they target
Biochemical mutagens affect the preservation of fungi and biodiversity estimations
Many fungi have significant industrial applications
or biosafety concerns and maintaining the original
characteristics is essential. The preserved fungi have to
represent the situation in nature for posterity, biodiversity
estimations, and taxonomic research. However, spontaneous
fungal mutations and secondary metabolites affecting
producing fungi are well known. There is increasing
interest in the preservation of microbes in Biological
Resource Centers (BRC) to ensure that the organisms
remain viable and stable genetically. It would be anathema
if they contacted mutagens routinely. However, for
the purpose of this discussion, there are three potential
sources of biochemical mutagens when obtaining individual
fungi from the environment: (a) mixtures of microorganisms
are plated routinely onto growth media
containing mutagenic antibiotics to control overgrowth
by contaminants, (b) the microbial mixtures may contain
microorganisms capable of producing mutagenic secondary
metabolites, and (c) target fungi for isolation may
produce “self” mutagens in pure culture. The probability
that these compounds could interact with fungi undermines
confidence in the preservation process and the
potential effects of these biochemical mutagens are considered
for the first time on strains held in BRC in this
review
Sensitivity to Gravitational Waves from Compact Binary Coalescences Achieved during LIGO's Fifth and Virgo's First Science Run
We summarize the sensitivity achieved by the LIGO and Virgo gravitational
wave detectors for compact binary coalescence (CBC) searches during LIGO's
fifth science run and Virgo's first science run. We present noise spectral
density curves for each of the four detectors that operated during these
science runs which are representative of the typical performance achieved by
the detectors for CBC searches. These spectra are intended for release to the
public as a summary of detector performance for CBC searches during these
science runs.Comment: 12 pages, 5 figure
Search for gravitational waves associated with the InterPlanetary Network short gamma ray bursts
We outline the scientific motivation behind a search for gravitational waves
associated with short gamma ray bursts detected by the InterPlanetary Network
(IPN) during LIGO's fifth science run and Virgo's first science run. The IPN
localisation of short gamma ray bursts is limited to extended error boxes of
different shapes and sizes and a search on these error boxes poses a series of
challenges for data analysis. We will discuss these challenges and outline the
methods to optimise the search over these error boxes.Comment: Methods paper; Proceedings for Eduardo Amaldi 9 Conference on
Gravitational Waves, July 2011, Cardiff, U
Swift follow-up observations of candidate gravitational-wave transient events
We present the first multi-wavelength follow-up observations of two candidate
gravitational-wave (GW) transient events recorded by LIGO and Virgo in their
2009-2010 science run. The events were selected with low latency by the network
of GW detectors and their candidate sky locations were observed by the Swift
observatory. Image transient detection was used to analyze the collected
electromagnetic data, which were found to be consistent with background.
Off-line analysis of the GW data alone has also established that the selected
GW events show no evidence of an astrophysical origin; one of them is
consistent with background and the other one was a test, part of a "blind
injection challenge". With this work we demonstrate the feasibility of rapid
follow-ups of GW transients and establish the sensitivity improvement joint
electromagnetic and GW observations could bring. This is a first step toward an
electromagnetic follow-up program in the regime of routine detections with the
advanced GW instruments expected within this decade. In that regime
multi-wavelength observations will play a significant role in completing the
astrophysical identification of GW sources. We present the methods and results
from this first combined analysis and discuss its implications in terms of
sensitivity for the present and future instruments.Comment: Submitted for publication 2012 May 25, accepted 2012 October 25,
published 2012 November 21, in ApJS, 203, 28 (
http://stacks.iop.org/0067-0049/203/28 ); 14 pages, 3 figures, 6 tables;
LIGO-P1100038; Science summary at
http://www.ligo.org/science/Publication-S6LVSwift/index.php ; Public access
area to figures, tables at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p110003
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