5,573 research outputs found
Logarithmic behavior of degradation dynamics in metal--oxide semiconductor devices
In this paper the authors describe a theoretical simple statistical modelling
of relaxation process in metal-oxide semiconductor devices that governs its
degradation. Basically, starting from an initial state where a given number of
traps are occupied, the dynamics of the relaxation process is measured
calculating the density of occupied traps and its fluctuations (second moment)
as function of time. Our theoretical results show a universal logarithmic law
for the density of occupied traps , i.e., the degradation is logarithmic and its amplitude depends on the
temperature and Fermi Level of device. Our approach reduces the work to the
averages determined by simple binomial sums that are corroborated by our Monte
Carlo simulations and by experimental results from literature, which bear in
mind enlightening elucidations about the physics of degradation of
semiconductor devices of our modern life
Emerging stronger? Assessing the outcomes of Habitat for Humanity’s housing reconstruction programmes following the Indian Ocean tsunami
Habitat for Humanity (HFH) built, rehabilitated or repaired homes for 25,000 families
in four countries in the five years following the Indian Ocean tsunami in 2004. As part
of a broader organizational and learning review in 2009-2010, HFH commissioned
Arup International Development to carry out an assessment of its post-tsunami housing
reconstruction programmes in India, Sri Lanka, Thailand, and Indonesia. The purpose
of this assessment was to investigate the extent to which HFH’s tsunami-response
housing reconstruction programmes had contributed to the development of sustainable
communities and livelihoods. Arup International Development undertook the assessment
using the ASPIRE tool they had developed with Engineers Against Poverty. Basing their
assessment on programme documentation and key informant interviews, household
questionnaires and workshops with communities in each country, they completed one
assessment for each country and a fifth assessment covering all four countries. This
enabled comparison of both the impact of these four programmes and how the outcomes
varied as a result of varying approaches and contextual issues. / The assessment found that HFH’s programme had made a significant contribution to
the development of sustainable communities and livelihoods. The provision of high
quality core homes had reduced household vulnerability and increased the standard
of living, while HFH’s participatory process had increased community cohesion and
developed positive relationships between communities and a range of external actors.
There were also areas for improvement such as: the incorporation of hazard assessment,
settlement planning and infrastructure at settlement level; greater community
participation in decision-making regarding settlement planning, house design and
the choice of appropriate construction techniques and technologies; greater focus on
livelihood support and diversification both during construction and after completion of
the housing programme; and complementing HFH’s experience in housing construction
with the specialist expertise of other actors to maximize the impact of its work
Guidelines for the recording and evaluation of pharmaco-EEG data in man: the International Pharmaco-EEG Society (IPEG)
The International Pharmaco-EEG Society (IPEG) presents updated guidelines summarising the requirements for the recording and computerised evaluation of pharmaco-EEG data in man. Since the publication of the first pharmaco-EEG guidelines in 1982, technical and data processing methods have advanced steadily, thus enhancing data quality and expanding the palette of tools available to investigate the action of drugs on the central nervous system (CNS), determine the pharmacokinetic and pharmacodynamic properties of novel therapeutics and evaluate the CNS penetration or toxicity of compounds. However, a review of the literature reveals inconsistent operating procedures from one study to another. While this fact does not invalidate results per se, the lack of standardisation constitutes a regrettable shortcoming, especially in the context of drug development programmes. Moreover, this shortcoming hampers reliable comparisons between outcomes of studies from different laboratories and hence also prevents pooling of data which is a requirement for sufficiently powering the validation of novel analytical algorithms and EEG-based biomarkers. The present updated guidelines reflect the consensus of a global panel of EEG experts and are intended to assist investigators using pharmaco-EEG in clinical research, by providing clear and concise recommendations and thereby enabling standardisation of methodology and facilitating comparability of data across laboratories
Connecting RS OPh to [some] Type Ia Supernovae
Aims: Recurrent nova systems like RS Oph have been proposed as a possible
channel to Type Ia Supernova explosions, based on the high mass of the
accreting white dwarf. Additional support to this hypothesis has been recently
provided by the detection of circumstellar material around SN2006X and
SN2007le, showing a structure compatible with that expected for recurrent nova
outbursts.In this paper we investigate the circumstellar environment of RS Oph
and its structure, with the aim of establishing a firmer and independent link
between this class of objects and Type Ia SN progenitors.
Methods: We study the time evolution of CaII, NaI and KI absorption features
in RS Oph, before, during, and after the last outburst, using multi-epoch,
high-resolution spectroscopy, and applying the same method adopted for SN2006X
and SN2007le.
Results: A number of components, blue-shifted with respect to the systemic
velocity of RS Oph, are detected. In particular, one feature strongly weakens
in the first two weeks after the outburst, simultaneously with the
disappearance of very narrow P-Cyg profiles overimposed on the much wider nova
emission lines of H, He, FeII and other elements.
Conclusions: We interpret these facts as the signature of density
enhancements in the circumstellar material, suggesting that the recurrent
eruptions might indeed create complex structures within the material lost by
the donor star. This establishes a strong link between RS Oph and the
progenitor system of the Type Ia SN2006X, for which similar features have been
detected.Comment: 8 pages, 10 figures. Accepted for publication in Astronomy and
Astrophysic
Bioactive compounds as potential angiotensin-converting enzyme II inhibitors against COVID-19: a scoping review
Objective and design The current study aimed to summarize the evidence of compounds contained in plant species with the ability to block the angiotensin-converting enzyme 2 (ACE-II), through a scoping review. Methods PubMed and Scopus electronic databases were used for the systematic search and a manual search was performed Results Studies included were characterized as in silico. Among the 200 studies retrieved, 139 studies listed after the exclusion of duplicates and 74 were included for the full read. Among them, 32 studies were considered eligible for the qualitative synthesis. The most evaluated class of secondary metabolites was flavonoids with quercetin and curcumin as most actives substances and terpenes (isothymol, limonin, curcumenol, anabsinthin, and artemisinin). Other classes that were also evaluated were alkaloid, saponin, quinone, substances found in essential oils, and primary metabolites as the aminoacid l-tyrosine and the lipidic compound 2-monolinolenin. Conclusion This review suggests the most active substance from each class of metabolites, which presented the strongest affinity to the ACE-II receptor, what contributes as a basis for choosing compounds and directing the further experimental and clinical investigation on the applications these compounds in biotechnological and health processes as in COVID-19 pandemic
Small bowel involvement is a prognostic factor in colorectal carcinomatosis treated with complete cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy
<p>Abstract</p> <p>Background</p> <p>Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) is a promising treatment for patients with peritoneal carcinomatosis (PC). Our objective was to identify new prognostic factors in patients with PC from colorectal cancer treated with this procedure.</p> <p>Methods</p> <p>All patients with PC from colorectal cancer treated by HIPEC from January 2000 to December 2007 were prospectively included. The tumor extension was assessed by the Peritoneal Cancer Index (PCI) and the residual disease was recorded using the completeness cytoreductive score (CCs). All clinical and treatment data were computed in univariate and multivariable analyses using survival as primary end point.</p> <p>Results</p> <p>We carried out 51 complete procedures in 49 consecutive patients. The mean PCI was 10. The allocation of CCs was: CC-0 = 37, CC-1 = 14. The five-year overall and progression-free survival rate were 40% and 20%, respectively. Several prognostic factors for survival were identified by univariate analysis: PCI < 9 (<it>P </it>< 0.001), CC-0 vs. CC-1 (<it>P </it>< 0.01) and involvement of area 4 (<it>P </it>= 0.06), area 5 (<it>P </it>= 0.031), area 7 (<it>P </it>= 0.014), area 8 (<it>P </it>= 0.022), area 10 (<it>P </it>< 0.0001), and area 11 (<it>P </it>= 0.02). Only the involvement of the distal jejunum (area 10) was significant in the multivariable analysis (<it>P </it>= 0.027).</p> <p>Conclusions</p> <p>We demonstrated that the involvement of area 10 (distal jejunum of the PCI score) was an independent factor associated with poor prognosis.</p
Neonatal anthropometry: a tool to evaluate the nutritional status and predict early and late risks
Neonatal anthropometry is an inexpensive, noninvasive and convenient tool for bedside evaluation, especially in sick and fragile neonates. Anthropometry can be used in neonates as a tool for several purposes: diagnosis of foetal malnutrition and prediction of early postnatal complications; postnatal assessment of growth, body composition and nutritional status; prediction of long-term complications including metabolic syndrome; assessment of dysmorphology; and estimation of body surface. However, in this age group anthropometry has been notorious for its inaccuracy and the main concern is to make validated indices available. Direct measurements, such as body weight, length and body circumferences are the most commonly used measurements for nutritional assessment in clinical practice and in field studies. Body weight is the most reliable anthropometric measurement and therefore is often used alone in the assessment of the nutritional status, despite not reflecting body composition. Derived indices from direct measurements have been proposed to improve the accuracy of anthropometry. Equations based on body weight and length, mid-arm circumference/head circumference ratio, and upper-arm cross-sectional areas are among the most used derived indices to assess nutritional status and body proportionality, even though these indices require further validation for the estimation of body composition in neonates
On the Nonabelian Aharonov Bohm Scattering of Spinless Particles
The Aharonov Bohm scattering for spinless, isospin 1/2, particles interacting
through a nonabelian Chern-Simons field is studied. Starting from the
relativistic quantum field theory and using a Coulomb gauge formulation, the
one loop renormalization program is implemented. Through the introduction of an
intermediary cutoff, separating the regions of high and low integration
momentum, the nonrelativistic limit is derived. The next to leading
relativistic approximation is also determined. In this approach quantum field
theory vacuum polarization effects are automatically incorporated.Comment: 20 pages, 8 figures, revtex. Misspelled reference corrected and new
references adde
Radiative Corrections to the Aharonov-Bohm Scattering
We consider the scattering of relativistic electrons from a thin magnetic
flux tube and perturbatively calculate the order , radiative
correction, to the first order Born approximation. We show also that the second
order Born amplitude vanishes, and obtain a finite inclusive cross section for
the one-body scattering which incorporates soft photon bremsstrahlung effects.
Moreover, we determine the radiatively corrected Aharonov-Bohm potential and,
in particular, verify that an induced magnetic field is generated outside of
the flux tube.Comment: 14 pages, revtex, 3 figure
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