6,364 research outputs found
El aire: hábitat y medio de transmisión de microorganismos
La atmósfera no tiene una microbiota autóctona pero es un medio para la dispersión de muchos tipos de microorganismos (esporas, bacterias, virus y hongos), procedentes de otros ambientes. Algunos han creado adaptaciones especializadas que favorecen su supervivencia y permanencia. Los microorganismos dispersados por el aire tiene una gran importancia biológica y económica. Producen enfermedades en plantas, animales y humanos, causan alteración de alimentos y materiales orgánicos y contribuyen al deterioro y corrosión de monumentos y metales. La Microbiología del aire comienza en el siglo XIX, con Pasteur y Miquel que diseñaron métodos para estudiar los microorganismos en el aire y descubrir la causa de algunas enfermedades. Desde entonces numerosos investigadores han trabajado en este campo tanto en el aire exterior como en recintos cerrados. Las enfermedades transmitidas por el aire, producidas por bacterias, virus y hongos, son las respiratorias (neumonía, tosferina, tuberculosis, legionelosis, resfriado, gripe), sistémicas (meningitis, sarampión, varicela, micosis) y alérgicas
Resistance Analysis for a Trimaran
Importance has been given to resistance analysis for various types of vessels; however explicit guidelines applied to multihull vessels have not been clearly defined. The purpose of this investigation is to highlight the importance of the vessel's layout in terms of three axes positioning, the transverse (separation), the longitudinal (stagger) and the vertical (draught) with respect to resistance analysis. A vessel has the potential to experience less resistance, at a particular range of speeds, for a vast selection of hull positioning. Many potential layouts create opportunities of various design for both the commercial and leisure market
Mekong Basin Focal Project: Synthesis report
The Mekong Basin Focal Project aims were to assess water use, water productivity and
water poverty in the basin, and analyse the opportunities and risks of change in water
management that influences water poverty.
The main issue facing the Lower Mekong is not water availability (except for seasonally in
certain areas such as northeast Thailand) but the impact of changed flows (which may
result from dam or irrigation development or climate change) on ecology, fish production,
access to water and food security. Poverty is generally decreasing in the Mekong, but the
poorer people are not sharing in the improvements. Water governance and sharing of
benefits is a key challenge for the Mekong
Design of an adaptive LNA for hand-held devices in a 1-V 90-nm standard RF CMOS technology: From circuit analysis to layout
[EN]: This paper deals the design of a reconfigurable Low-Noise Amplifier (LNA) for the next generation of wireless hand-held devices by using a lumped circuit approach based on physical laws. The purpose is not only to present simulation results showing the fulfillment of different standard specifications, but also to demonstrate that each design step has a physical meaning such that the mathematical design flow is simple as well as suitable for hand-work in both laboratory and classroom. The circuit under analysis, which is designed according to technological design rules of a 90nm CMOS technology, is a two-stage topology including inductive-source degeneration, MOS-varactor based tuning networks, and programmable bias currents. This proposal, with reduced number of inductors and minimum power dissipation, adapts its performance to different standard specifications; the LNA is designed to cope with the requirements of GSM (PCS1900), WCDMA, Bluetooth and WLAN (IEEE 802.11b-g). In order to evaluate the effect of technology parasitics on the LNA performance, simulation results demonstrate that the LNA features NF16dB, S11-3.3 dBm over the 1.85-2.48 GHz band. For all the standards under study the adaptive power consumption varies from 25.3 mW to 53.3mW at a power supply of 1-V. The layout of the reconfigurable LNA occupies an area of 1.8mm2.[ES]: Este trabajo presenta el diseño de un amplificador de bajo ruido, LNA (del inglés Low‐Noise Amplifier) reconfigurable para la siguiente generación de dispositivos portátiles
de comunicación inalámbricos, usando la aproximación de circuitos concentrados sustentada
en leyes físicas. El propósito de este trabajo no
es sólo presentar resultados de simulación que
muestran el cumplimiento de especificaciones para
cada estándar, sino también demostrar que cada
paso de diseño tiene un significado físico
haciendo que el procedimiento matemático de
diseño sea simple y adecuado para el trabajo a mano tanto para actividades en laboratorio como en
el aula. El circuito bajo análisis, diseñado en
una tecnología CMOS 90nm, consta de dos etapas
que incluyen degeneración inductiva de fuente,
redes de entonado basadas en varactores MOS, y corrientes de polarización programables. Esta
propuesta, con reducido número de inductores y
mínima disipación de potencia, adapta su desempeño
a las diversas especificaciones de cada estándar;
el LNA se diseña para cubrir los requerimientos
de GSM (PCS1900), WCDMA, Bluetooth y WLAN (IEEE
802.11b‐g). Para evaluar el efecto de las no idealidades de la tecnología en el desempeño del
LNA, las simulaciones demuestran que el circuito
cumple parámetros como NF16dB, S11<
‐5.5dB, S22‐3.3dBm en la banda 1.85‐
2.48GHz. Para todos los estándares bajo estudio,
el consumo adaptivo de potencia varía de 25.3 mW
a 53.3mW usando una fuente de alimentación de 1‐V.
El patrón geométrico del LNA reconfigurable consume un área de 1.8mm2.Peer Reviewe
Thiol precursors in Catarratto Bianco Comune and Grillo grapes and effect of clarification conditions on the release of varietal thiols in wine
Background and aims: Varietal thiols characterize the typical aroma of several white wines, as Sauvignon blanc. Their presence was suggested in two Sicilian grape cultivars, Catarratto Bianco Comune (CBC) and Grillo, thought it was not analytically proved to date.
Methods and Results: Varietal thiol precursors and free varietal thiols were assessed in CBC and Grillo grapes, musts and wines by UPLC/high resolution mass spectrometry (HRMS). The isobaric compounds S-3-(hexanal)-glutathione (GSH-3MHAl) and S-3-(4-mercapto-4-methylpentan-2-one)-glutathione (GSH-4MMP) were discriminated by comparing their accurate masses and HR-MS/MS spectra with those of their synthetic standards. GSH-3MHAl, S-3-(hexan-1-ol)-glutathione (GSH-3MH) and S-3-(hexan-1-ol)-cysteine occurred in grape, must and wine, while GSH-4MMP and its hydrolysed forms did not. Their amounts decreased during the industrial winemaking processes, mostly following the grape pressing. We compared clarification conditions exposing must to either air or CO2 in terms of thiol precursors\u2019 and free thiols\u2019 content in wine. However, negligible differences were observed. Concentrations of free thiols in the range 400\u20131100 ng/L were found in the wines and they were not affected to the two clarification conditions adopted.
Conclusion: The isobaric GSH-3MHAl and GSH-4MMP were clearly distinguished for the first time by UPLC-HRMS through their retention times and MS spectra. The varietal thiols were firstly revealed CBC and Grillo wines. The air-free and air- exposed clarification poorly affected the levels of varietal thiols.
Significance of the study: This research highlights the major impact of the varietal thiols (mainly 3\u2013mercapto-hexan-1-ol and its acetate form) on the sensory properties of CBC and Grillo wines
The finding of vascular and urinary anomalies in the harvested kidney for transplantation.
INTRODUCTION: In kidney transplantation, anatomical vascular and excretory anomalies may represent causes of failure. Today's surgical techniques have made the most of the organs with anatomic anomalies and iatrogenic injury successfully used for transplantation.
MATERIALS AND METHODS: From January 2000 to June 2006, we harvested 230 kidneys, of including 88 kidneys (20%) with vascular, urinary, or vascular-urinary anomalies; 64 kidneys were implanted and 15 were sent to other transplantation centers. Only 9 kidneys were not appropriate for transplantation.
RESULTS: All patients who received kidneys with the above-mentioned anomalies were carefully examined after the transplantation and short-term and long-term complications were evaluated with respect to controls without anomalies.
DISCUSSION: Renal anatomic anomalies are frequently observed during kidney transplantation and may produce postsurgical complications. However, the presence of these anomalies does not necessarily imply the impossibility of using the kidney for a transplant, especially because of improved surgical techniques. Our experience in transplantation procedures showed that even if kidneys present the above-mentioned anomalies they can still be considered appropriate for transplantation when we perform a correct harvesting/back-table transplant surgery. So vascular and urinary anomalies have to be considered always an incentive to research new surgical solutions and to perform a careful surgical technique
Nonpuerperal Breast Infection
Objective: We undertook a microbiological study of purulent specimens from women with symptomatic breast abscesses
Neuroglial involvement in abnormal glutamate transport in the cochlear nuclei of the Igf1—/— mouse
Insulin-like growth factor 1 (IGF-1) is a powerful regulator of synaptic activity and a
deficit in this protein has a profound impact on neurotransmission, mostly on excitatory
synapses in both the developing and mature auditory system. Adult Igf1—/— mice
are animal models for the study of human syndromic deafness; they show altered
cochlear projection patterns into abnormally developed auditory neurons along with
impaired glutamate uptake in the cochlear nuclei, phenomena that probably reflect
disruptions in neuronal circuits. To determine the cellular mechanisms that might
be involved in regulating excitatory synaptic plasticity in 4-month-old Igf1—/— mice,
modifications to neuroglia, astroglial glutamate transporters (GLTs) and metabotropic
glutamate receptors (mGluRs) were assessed in the cochlear nuclei. The Igf1—/— mice
show significant decreases in IBA1 (an ionized calcium-binding adapter) and glial
fibrillary acidic protein (GFAP) mRNA expression and protein accumulation, as well
as dampened mGluR expression in conjunction with enhanced glutamate transporter
1 (GLT1) expression. By contrast, no differences were observed in the expression
of glutamate aspartate transporter (GLAST) between these Igf1—/— mice and their
heterozygous or wildtype littermates. These observations suggest that congenital IGF-1
deficiency may lead to alterations in microglia and astrocytes, an upregulation of GLT1,
and the downregulation of groups I, II and III mGluRs. Understanding the molecular,
biochemical and morphological mechanisms underlying neuronal plasticity in a mouse
model of hearing deficits will give us insight into new therapeutic strategies that could
help to maintain or even improve residual hearing when human deafness is related to
IGF-1 deficiencyThis work was supported by the Spanish Ministerio de Economía
y Competitividad (MINECO; SAF2016-788898-C2-1R) to JJ and
VF-S; Seventh Framework Programme (FP7)-HEALTH-
2012-INNOVATON (#304925) to JJ; CIBERER/FEDER
ACCI-ER16P5AC7091 and ER17P5AC7612 to LR-R;
and Spanish MINECO/FEDER (SAF2014-53979-R), FP7-
PEOPLE-2013-IAPP TARGEAR, CIBERER/FEDER (ACCIER16P5AC7091
and ER17P5AC7612) to IV-N. LR-R holds a
contract supported by CIBERER (Institute of Health Carlos III)
co-financed with FEDER fund
Implementation of binary stochastic STDP learning using chalcogenide-based memristive devices
The emergence of nano-scale memristive devices encouraged many different
research areas to exploit their use in multiple applications. One of the
proposed applications was to implement synaptic connections in bio-inspired
neuromorphic systems. Large-scale neuromorphic hardware platforms are being
developed with increasing number of neurons and synapses, having a critical
bottleneck in the online learning capabilities. Spike-timing-dependent
plasticity (STDP) is a widely used learning mechanism inspired by biology which
updates the synaptic weight as a function of the temporal correlation between
pre- and post-synaptic spikes. In this work, we demonstrate experimentally that
binary stochastic STDP learning can be obtained from a memristor when the
appropriate pulses are applied at both sides of the device
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