750 research outputs found
Quale paradigma per il futuro?
Il paper presenta il dibattito tenutosi il 4 marzo 2009 durante il seminario “A Nord e a Sud: l’Italia e la crisi internazionale”, presso l’Università L’Orientale di Napoli: \ud
il cambiamento dei sistemi economico-sociali e la riformulazione dei modelli teorici sin qui utilizzati sono stati al centro della discussione.\u
Spontaneous and stimulated emission tuning characteristics of a Josephson junction in a microcavity
We have investigated theoretically the tuning characteristics of a Josephson
junction within a microcavity for one-photon spontaneous emission and for
one-photon and two-photon stimulated emission. For spontaneous emission, we
have established the linear relationship between the magnetic induction and the
voltage needed to tune the system to emit at resonant frequencies. For
stimulated emission, we have found an oscillatory dependence of the emission
rate on the initial Cooper pair phase difference and the phase of the applied
field. Under specific conditions, we have also calculated the values of the
applied radiation amplitude for the first few emission maxima of the system and
for the first five junction-cavity resonances for each process. Since the
emission of photons can be controlled, it may be possible to use such a system
to produce photons on demand. Such sources will have applications in the fields
of quantum cryptography, communications and computation
Understanding edge-connectivity in the Internet through core-decomposition
Internet is a complex network composed by several networks: the Autonomous
Systems, each one designed to transport information efficiently. Routing
protocols aim to find paths between nodes whenever it is possible (i.e., the
network is not partitioned), or to find paths verifying specific constraints
(e.g., a certain QoS is required). As connectivity is a measure related to both
of them (partitions and selected paths) this work provides a formal lower bound
to it based on core-decomposition, under certain conditions, and low complexity
algorithms to find it. We apply them to analyze maps obtained from the
prominent Internet mapping projects, using the LaNet-vi open-source software
for its visualization
Influence of neighbourhood socioeconomic position on the transition to type II diabetes in older Mexican Americans: the Sacramento Area Longitudinal Study on Aging
To examine the influence of neighbourhood socioeconomic position (NSEP) on development of diabetes over time
Guts and brains : an integrative approach to the hominin record
The human brain and its one hundred billion neurons compose the most complex organ in the body and harness more than 20 per cent of all the energy we produce. Why do we have such large and energy-demanding brains, and how have we been able to afford such an expensive organ for thousands of years? Guts and Brains discusses the key variables at stake in such a question, including the relationship between brain size and diet, diet and social organization, and large brains and the human sexual division of labour. This interdisciplinary volume provides an entry for the reader into understanding the development of both early primates and our own species.Wetensch. publicati
Invariant indices of polarimetric purity. Generalized indices of purity for nxn covariance matrices
A proper set of indices characterizing the polarimetric purity of light and
material media is defined from the eigenvalues of the corresponding coherency
matrix. A simple and generalizable relation of these indices with the current
parameters characterizing the global purity is obtained. A general definition
for systems characterized by nxn positive semidefinite Hermitian matrices is
introduced in terms of the corresponding eigenvalues and diagonal Gell-Mann
matrices. The set of n-1 indices of purity has a nested structure and provide
complete information about the statistical purity of the system.Comment: 19 pages, 2 figure
The association of parental and offspring educational attainment with systolic blood pressure, fasting blood glucose and waist circumference in Latino adults
Objective: The objective of the study is to evaluate the association of intergenerational educational attainment with cardiovascular disease (CVD) risk factors among US Latinos. Methods: We used cross-sectional data from the Niños Lifestyle and Diabetes Study, an offspring cohort of middle-aged Mexican-Americans whose parents participated in the Sacramento Latino Study on Aging. We collected educational attainment, demographic and health behaviours and measured systolic blood pressure (SBP), fasting glucose and waist circumference. We evaluated the association of parental, offspring and a combined parent–offspring education variable with each CVD risk factor using multivariable regression. Results: Higher parental education was associated only with smaller offspring waist circumference. In contrast, higher offspring education was associated with lower SBP, fasting glucose and smaller waist circumference. Adjustment for parental health behaviours modestly attenuated these offspring associations, whereas adjustment for offspring health behaviours and income attenuated the associations of offspring education with offspring SBP and fasting glucose but not smaller waist circumference, even among offspring with low parental education. Conclusions: Higher offspring education is associated with lower levels of CVD risk factors in adulthood, despite intergenerational exposure to low parental education
A cluster-randomised controlled trial to test the efficacy of facemasks in preventing respiratory viral infection among Hajj pilgrims
BACKGROUND: Cost-effective interventions are needed to control the transmission of viral respiratory tract infections (RTIs) in mass gatherings. Facemasks are a promising preventive measure, however, previous studies on the efficacy of facemasks have been inconclusive. This study proposes a large-scale facemask trial during the Hajj pilgrimage in Saudi Arabia and presents this protocol to illustrate its feasibility and to promote both collaboration with other research groups and additional relevant studies.
METHODS/DESIGN: A cluster-randomised controlled trial is being conducted to test the efficacy of standard facemasks in preventing symptomatic and proven viral RTIs among pilgrims during the Hajj season in Mina, Mecca, Saudi Arabia. The trial will compare the 'supervised use of facemasks' versus 'standard measures' among pilgrims over several Hajj seasons. Cluster-randomisation will be done by accommodation tents with a 1:1 ratio. For the intervention tents, free facemasks will be provided to be worn consistently for 7days. Data on flu-like symptoms and mask use will be recorded in diaries. Nasal samples will be collected from symptomatic recruits and tested for nucleic acid of respiratory viruses. Data obtained from questionnaires, diaries and laboratory tests will be analysed to examine whether mask use significantly reduces the frequency of laboratory-confirmed respiratory viral infection and syndromic RTI as primary outcomes.
CONCLUSIONS: This trial will provide valuable evidence on the efficacy of standard facemask use in preventing viral respiratory tract infections at mass gatherings. This study is registered at the Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN: ACTRN12613001018707 (http://www.anzctr.org.au)
Metoclopramide protection of diazinon-induced toxicosis in chickens
The efficacy of metoclopramide for preventing organophosphate insecticide-induced (diazinon) toxicosis was evaluated in 7~14 days old chicks. Injection of metoclopramide at 25 mg/kg, s.c. 15 min before diazinon increased the oral 24 h median lethal dose of the insecticide in the chicks by 80%. Metoclopramide alone inhibited the in vitro and in vivo plasma and whole brain cholinesterase activities of the chicks. Metoclopramide pretreatment at 100 mg/kg, s.c. reduced the extent of cholinesterase inhibition that was caused by diazinon (10 mg/kg, p.o.) in the plasma and whole brain by 24% and 7%, respectively. Diazinon at 10 mg/kg, p.o. produced signs of cholinergic toxicosis in the chicks, and these signs included salivation, lacrimation, gasping and convulsions within 2 h, and the 2-h and 24-h lethalities were 88 and 100%, respectively. Metoclopramide at the dose rates of 12.5, 25, 50, 100 and 200 mg/kg, s.c. given 15 min before diazinon (10 mg/kg, p.o.) variably decreased the occurrence of toxic manifestations in the chicks. The highest dose of metoclopramide (200 mg/kg, s.c.) reduced the 2-h and 24-h lethality of diazinon to 75% each and it reduced the overall toxicity score of diazinon by 32%. The data suggest that metoclopramide pretreatment only partially protected chicks against the acute toxicity of diazinon
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