239 research outputs found
Evaluation of WRF model configurations for dynamic downscaling of tropical cyclones activity over the North Atlantic basin for Lagrangian moisture tracking analysis in future climate
This study assessed five well-established physics suites of the Weather Research and Forecasting (WRF) model in operational forecasting systems in the North Atlantic (NATL) basin or from previous sensitive experiments for dynamic downscaling tropical cyclone (TC) activity. We performed long-term simulations for the 2020 TC season in the NATL and compared the WRF tracks against the HURDAT2 dataset from the US National Hurricane Center. Among the tested configurations, the analysis revealed that the Kain-Fritsch, Purdue Lin, BouLac and revised MM5 schemes for cumulus, microphysics, planetary boundary layer and surface layer, respectively (hereafter WT), outperformed all four others in terms of TC frequency, track density and intensity and showed good performance in the cyclone accumulated energy and TC landfalling locations. In addition, WT well-captured the spatial distribution of accumulated TC precipitation and moisture uptake patterns, although it overestimated the precipitation maxima. Likewise, it agreed on the relative moisture contribution from fixed moisture sources (i.e., Gulf of Mexico, Caribbean Sea, tropical NATL, and western NATL) in the NATL basin. Overall, this study highlighted the high potential of using the WT physics suite in WRF for downscaling TC activity over the NATL basin, which will be useful for TC Lagrangian moisture sources analysis in future climate.Agencia Estatal de InvestigaciĂłn | Ref. PID2021-122314OB-I00Xunta de Galicia | Ref. ED431C 2021/44Xunta de Galicia | Ref. ED481B-2023/016Xunta de Galicia | Ref. ED481D 2022/020Universidade de Vigo/CISU
Contribución al conocimiento del género Anthyllis L. (Fabaceae) en la Peninsula Ibérica. A. plumosa sp. nov.
In this paper a morphological, palynologicaland caryologicalstudy of three species of Anthyllis (sect. Oreanthyllis)is included. As a consecuencea newspecies A.plumosa E. DomiÌnguez from the dolomitics sands of Sierra de Almijara (MaÌlaga) is described.Se realiza un estudio morfoloÌgico, palinoloÌgico y carioloÌgico de tres especies del geÌnero Anthyllis (sect. Oreanthyllis), describieÌndose una nueva especie, A. plumosa E. DomiÌnguez procedente de las arenas dolomiÌticas de la Sierra de Almijara (MaÌlaga)
Recent changes of relative humidity: regional connections with land and ocean processes
We analyzed changes in surface relative humidity (RH) at the global scale from 1979 to 2014 using both observations and the ERA-Interim dataset. We compared the variability and trends in RH with those of land evapotranspiration and ocean evaporation in moisture source areas across a range of selected regions worldwide. The sources of moisture for each particular region were identified by integrating different observational data and model outputs into a Lagrangian approach. The aim was to account for the possible role of changes in air temperature over land, in comparison to sea surface temperature (SST), but also the role of land evapotranspiration and the ocean evaporation on RH variability. The results demonstrate that the patterns of the observed trends in RH at the global scale cannot be linked to a particular individual physical mechanism. Our results also stress that the different hypotheses that may explain the decrease in RH under a global warming scenario could act together to explain recent RH trends. Albeit with uncertainty in establishing a direct causality between RH trends and the different empirical moisture sources, we found that the observed decrease in RH in some regions can be linked to lower water supply from land evapotranspiration. In contrast, the empirical relationships also suggest that RH trends in other target regions are mainly explained by the dynamic and thermodynamic mechanisms related to the moisture supply from the oceanic source regions. Overall, while this work gives insights into the connections between RH trends and oceanic and continental processes at the global scale, further investigation is still desired to assess the contribution of both dynamic and thermodynamic factors to the evolution of RH over continental regions.Ministerio de EconomĂa y Competitividad | Ref. PCIN-2015-220Ministerio de EconomĂa y Competitividad | Ref. CGL2014-52135-C03-01Ministerio de EconomĂa y Competitividad | Ref. CGL2014-60849-JINEuropean Commission | Ref. n. 69046
Relaciones filogenĂ©ticas en Erysimun (Brassicaceae) de las Cordilleras BĂ©ticas (SE PenĂnsula IbĂ©rica)
The Baetic mountains, located in the southern Iberian Peninsula, is a major hotspot of biodiversity in the Mediterranean Basin, constituting one of the most important glacial refugia for vascular plants in Europe. Despite their relatively limited extension, the Baetic Mountains contain almost 50% of the total endemic Erysimum species in the Iberian Peninsula. The broadly distributed Erysimum genus has diversified profusely in the Mediterranean region, with more than a hundred species described in the area, out of a total of c. 200 species included in the genus. We used two plastid DNA regions (ndhF and trnT-L) and one nuclear DNA region (ITS1-5.8S rDNA-ITS2), with 3,556 bp total length, to carry out phylogenetic analysis by Bayesian inference, maximum likelihood and maximum parsimony, in order to explore the evolutionary relationships between the Erysimum species inhabiting these ranges. Analyses of concatenated sequences from the two genomes identified two main clades with no overlap in species composition so that samples from the same species fell within the same major clade. The phylogenetic relationships depicted by those two clades do not give support to the E. nevadense group, previously proposed on taxonomic grounds. In addition, our results indicated recurrent changes in flower colour in the Baetic Erysimum species although, alternatively, reticulate evolution, which is suggested by incongruent position of taxa in the different trees, may have also affected this trait.Las cordilleras BĂ©ticas, localizadas en el sudeste de la PenĂnsula IbĂ©rica,
representan una importante zona para la biodiversidad de la cuenca mediterrĂĄnea,
constituyendo uno de los refugios glaciares mĂĄs destacados de
plantas vasculares en Europa. A pesar de su extensiĂłn relativamente limitada,
las cordilleras BĂ©ticas albergan casi el 50% del total de las especies
endĂ©micas de Erysimum de la PenĂnsula IbĂ©rica. Erysimum es un gĂ©nero
ampliamente distribuido, que se ha diversificado profusamente en la regiĂłn
mediterrĂĄnea, con mĂĄs de un centenar de especies descritas en dicha ĂĄrea,
del total de las alrededor de 200 especies incluidas en el género. Usamos
dos regiones de ADN plastidial (ndhF y trnT-L) y una regiĂłn de ADN nuclear
(ITS1-5.8S rDNA-ITS2), con una longitud total de 3.556 pb, para llevar a
cabo anålisis filogenéticos mediante inferencia bayesiana, måxima verosimilitud
y mĂĄxima parsimonia, con el fin de explorar las relaciones evolutivas
entre las especies de Erysimum que habitan en Ă©stas cordilleras.
El anĂĄlisis de secuencias concatenadas de los dos genomas identifica dos
clados principales y las muestras de la misma especie aparecen siempre en
un clado o en el otro pero no en ambos. Las relaciones filogenéticas que
indican esos dos clados no apoyan la circunscripciĂłn del grupo taxonĂłmico
E. nevadense, previamente definido en dicho género. Ademås, los anålisis
indican cambios recurrentes en el color floral de las especies de Erysimum
que habitan los Sistemas BĂ©ticos aunque la evoluciĂłn reticulada, que sugiere
la posición de algunos taxones en uno y otro årbol, puede haber también
afectado a este rasgo, lo que serĂa una hipĂłtesis alternativa.This study has been supported
by MARM (078/2007), Junta de AndalucĂa (P07-RNM-02869 and
P11-RNM-7676), MONTES Consolider-Ingenio (CSD2008-00040), and
Spanish MCyT (CGL2009-07015, and CGL2012-34736) grants. AJMP and
MA were supported by Spanish Education and Science grants AP-2006-
00685 and BES-2007-14206, respectively
Computer-Aided Structure-Based Design of Multitarget Leads for Alzheimerâs Disease
Alzheimerâs disease is a neurodegenerative pathology with unmet clinical needs. A highly desirable approach to this syndrome would be to find a single lead that could bind to some or all of the selected biomolecules that participate in the amyloid cascade, the most accepted route for Alzheimer disease genesis. In order to circumvent the challenge posed by the sizable differences in the binding sites of the molecular targets, we propose a computer-assisted protocol based on a pharmacophore and a set of required interactions with the targets that allows for the automated screening of candidates. We used a combination of docking and molecular dynamics protocols in order to discard nonbinders, optimize the best candidates, and provide a rationale for their potential as inhibitors. To provide a proof of concept, we proceeded to screen the literature and databases, a task that allowed us to identify a set of carbazole-containing compounds that initially showed affinity only for the cholinergic targets in our experimental assays. Two cycles of design based on our protocol led to a new set of analogues that were synthesized and assayed. The assay results revealed that the designed inhibitors had improved affinities for BACE-1 by more than 3 orders of magnitude and also displayed amyloid aggregation inhibition and affinity for AChE and BuChE, a result that led us to a group of multitarget amyloid cascade inhibitors that also could have a positive effect at the cholinergic levelFinancial support from the Ministerio de Economia y
Competitividad of Spain (Project CTQ2011-22436) and the
Xunta de Galicia (CN2011/047 and 10CSA209063PR) is
gratefully acknowledgedS
8âAminomethylâ7âhydroxyâ4âmethylcoumarins as Multitarget Leads for Alzheimer's Disease
This is the peer reviewed version of the following article: DomĂnguez, J., FernĂĄndez-Nieto, F., Brea, J., Catto, M., Paleo, M., & Porto, S. et al. (2016). 8-Aminomethyl-7-hydroxy-4-methylcoumarins as Multitarget Leads for Alzheimer's Disease. Chemistryselect, 1(11), 2742-2749, which has been published in final form at https://doi.org/10.1002/slct.201600735.
This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsThis work is part of our ongoing research in the discovery of multitarget therapeutic agents for Alzheimer's disease (AD). A literature screening, based on our recently proposed pharmacophore, led to the identification of 8âaminomethylâ7âhydroxyâ4âmethyl coumarins as potential multitarget leads for AD. The results of a computerâassisted protocol developed by us to validate multitarget hits for AD indicated that our coumarin candidates were viable leads only for AChE inhibition as later validated by biological assays. The results of BChE binding and propidium displacement assays indicate that our first generation compounds bind to the PAS site in AChE. We designed new generations of coumarin derivatives with a longer substituent at position 8 aimed at leads with more efficient interaction at the catalytic anionic site (CAS). Inhibition data and docking simulations indicated that an anilinoâcapping group reached the CAS region of AChE and determined also a higher inhibitory potency towards BChE. The best compound obtained, with a Nâbenzylpiperidine fragment, displayed subâmicromolar affinity for AChE, affinity for BChE, and precluded AÎČâamyloid aggregation with a potency similar to that of 9,10âanthraquinone, making it a multitarget lead viable for further improvementFinancial support from the Ministerio de Economia y Competitividad of Spain (Project CTQ2014â55208âP) and the Xunta de Galicia (10CSA209063PR and GRC2014/029) is gratefully acknowledged. The Italian authors thank the University of Bari for partial financial support (Fondi di Ateneo 2014â2015)S
MAGIC Upper Limits for two Milagro-detected, Bright Fermi Sources in the Region of SNR G65.1+0.6
We report on the observation of the region around supernova remnant G65.1+0.6
with the stand-alone MAGIC-I telescope. This region hosts the two bright GeV
gamma-ray sources 1FGL J1954.3+2836 and 1FGL J1958.6+2845. They are identified
as GeV pulsars and both have a possible counterpart detected at about 35 TeV by
the Milagro observatory. MAGIC collected 25.5 hours of good quality data, and
found no significant emission in the range around 1 TeV. We therefore report
differential flux upper limits, assuming the emission to be point-like (<0.1
deg) or within a radius of 0.3 deg. In the point-like scenario, the flux limits
around 1 TeV are at the level of 3 % and 2 % of the Crab Nebula flux, for the
two sources respectively. This implies that the Milagro emission is either
extended over a much larger area than our point spread function, or it must be
peaked at energies beyond 1 TeV, resulting in a photon index harder than 2.2 in
the TeV band.Comment: 8 pages, 3 figures, 1 tabl
Simultaneous multi-frequency observation of the unknown redshift blazar PG 1553+113 in March-April 2008
The blazar PG 1553+113 is a well known TeV gamma-ray emitter. In this paper,
we determine its spectral energy distribution using simultaneous
multi-frequency data in order to study its emission processes. An extensive
campaign was carried out between March and April 2008, where optical, X-ray,
high-energy (HE) gamma-ray, and very-high-energy (VHE) gamma-ray data were
obtained with the KVA, Abastumani, REM, RossiXTE/ASM, AGILE and MAGIC
telescopes, respectively. This is the first simultaneous broad-band (i.e.,
HE+VHE) gamma-ray observation, though AGILE did not detect the source. We
combine data to derive source's spectral energy distribution and interpret its
double peaked shape within the framework of a synchrotron self compton modelComment: 5 pages, 2 figures, publishe
A search for spectral hysteresis and energy-dependent time lags from X-ray and TeV gamma-ray observations of Mrk 421
Blazars are variable emitters across all wavelengths over a wide range of
timescales, from months down to minutes. It is therefore essential to observe
blazars simultaneously at different wavelengths, especially in the X-ray and
gamma-ray bands, where the broadband spectral energy distributions usually
peak.
In this work, we report on three "target-of-opportunity" (ToO) observations
of Mrk 421, one of the brightest TeV blazars, triggered by a strong flaring
event at TeV energies in 2014. These observations feature long, continuous, and
simultaneous exposures with XMM-Newton (covering X-ray and optical/ultraviolet
bands) and VERITAS (covering TeV gamma-ray band), along with contemporaneous
observations from other gamma-ray facilities (MAGIC and Fermi-LAT) and a number
of radio and optical facilities. Although neither rapid flares nor significant
X-ray/TeV correlation are detected, these observations reveal subtle changes in
the X-ray spectrum of the source over the course of a few days. We search the
simultaneous X-ray and TeV data for spectral hysteresis patterns and time
delays, which could provide insight into the emission mechanisms and the source
properties (e.g. the radius of the emitting region, the strength of the
magnetic field, and related timescales). The observed broadband spectra are
consistent with a one-zone synchrotron self-Compton model. We find that the
power spectral density distribution at Hz from the
X-ray data can be described by a power-law model with an index value between
1.2 and 1.8, and do not find evidence for a steepening of the power spectral
index (often associated with a characteristic length scale) compared to the
previously reported values at lower frequencies.Comment: 45 pages, 15 figure
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