486 research outputs found
Beyond single-photon localization at the edge of a Photonic Band Gap
We study spontaneous emission in an atomic ladder system, with both
transitions coupled near-resonantly to the edge of a photonic band gap
continuum. The problem is solved through a recently developed technique and
leads to the formation of a ``two-photon+atom'' bound state with fractional
population trapping in both upper states. In the long-time limit, the atom can
be found excited in a superposition of the upper states and a ``direct''
two-photon process coexists with the stepwise one. The sensitivity of the
effect to the particular form of the density of states is also explored.Comment: to appear in Physical Review
Design, Construction and Evaluation of a Dual Operation Seed and Fertilizer Broadcaster for Farmers
This paper presents a report on the design, construction and evaluation of a dual operation seed and fertilizer broadcasting device, an appropriate agricultural technology especially, for small scale peasant farmers in both rural and urban areas. It is an appropriate technology because its features eliminate the short coming on both traditional and existing physical devices being used for seed and fertilizer broadcasting. Relevant literature was reviewed. Engineering design was adopted in this study. Preliminary investigation was carried out to reliably and objectively establish the need for the new product. In carrying out the preliminary investigation, thirty (30) open ended and semi structured questionnaire were used to sample thirty end users’ opinions on existing seed and fertilizer broadcasting devices. Percentage was used for analysis of data. The area of study for the preliminary investigation and the final study was Adamawa and Gombe States of Nigeria. The preliminary investigation revealed that farmers are dissatisfied with the high cost of the tractor mounted fertilizer broadcaster and they also expressed dissatisfaction with the traditional method since it is slow, energy consuming and has high health hazards. For this, respondents expressed a need for a device that is potable, has low energy requirement and is relatively cheap. After establishing the need for the new device, design specification, design criteria, production and assembly drawings were made. Materials selection was based on the design calculation made. The evaluation result revealed that the new product carried out the function for which it was designed. It was therefore recommended to entrepreneurs for mass production and for use by peasant farmers. Keywords: Design, Construction, Evaluation, Fertilizer, Broadcasting. DOI: 10.7176/IEL/11-3-02 Publication date:October 31st 202
Ultrasonically enabled low temperature electroless plating for sustainable electronic manufacture
Intrauterine growth restriction is associated with persistent juxtamedullary expression of renin in the fetal kidney
Intrauterine growth restriction is associated with persistent juxtamedullary expression of renin in the fetal kidney.BackgroundIntrauterine growth restriction (IUGR) has been linked to impaired renal function and hypertension, suggesting that an adverse prenatal environment could alter kidney development and renin production.MethodsImmunohistochemistry and in situ hybridization were employed to localize renin-containing cells (RCCs) in the deep, middle, and superficial zones of autopsy kidney sections, in parallel with histologic maturation, from unexplained stillborn fetuses of normal weight (N = 26) and stillborn fetuses with IUGR (N = 17).ResultsIn the control group, the number of RCC per 100 glomeruli in the deep zone decreased with advancing gestation from 40 at 20weeks gestation to five at term (P < 0.001), whereas the opposite change was found in the superficial zone (increase from 5 per 100 to 55 per 100; P < 0.001). In the IUGR group, the density of RCCs in both the superficial and deep zones was similar to the control group at 20weeks, and no shift in renin gene expression was observed as gestation advanced. Histologic maturation was unaltered.ConclusionsRenin gene expression persists and predominates in the deep renal cortex of the stillborn IUGR fetus, and could contribute to the pathogenesis of neonatal oliguria and/or hypertension during postnatal life
Quantum Gravitational Corrections to the Nonrelativistic Scattering Potential of Two Masses
We treat general relativity as an effective field theory, obtaining the full
nonanalytic component of the scattering matrix potential to one-loop order. The
lowest order vertex rules for the resulting effective field theory are
presented and the one-loop diagrams which yield the leading nonrelativistic
post-Newtonian and quantum corrections to the gravitational scattering
amplitude to second order in G are calculated in detail. The Fourier
transformed amplitudes yield a nonrelativistic potential and our result is
discussed in relation to previous calculations. The definition of a potential
is discussed as well and we show how the ambiguity of the potential under
coordinate changes is resolved.Comment: 27 pages, 17 figure
A solvable model of a random spin-1/2 XY chain
The paper presents exact calculations of thermodynamic quantities for the
spin-1/2 isotropic XY chain with random lorentzian intersite interaction and
transverse field that depends linearly on the surrounding intersite
interactions.Comment: 14 pages (Latex), 2 tables, 13 ps-figures included, (accepted for
publication in Phys.Rev.B
Negative Consequences of Substance Use in European University Students: Results from Project SNIPE
Background: University students are a risk group for heavy substance use and the experience of various potentially severe negative substance use consequences which may impact on their health, social, and academic functioning. Whilst the experience of negative consequences of substance use is well understood in North American student samples, there is little data on these experiences in European students. In order to develop effective harm prevention and reduction interventions for students’ substance use, there needs to be an understanding of the types of consequences experienced in European student samples. Objectives: The aim of the study was to investigate the prevalence and predictors of the experience of negative substance use-related consequences amongst university students in 7 European countries. Methods: University students (n = 4,482) in Belgium, Denmark, Germany, the Slovak Republic, Spain, Turkey, and the UK completed an online survey of their substance use behaviours and the experience of associated negative consequences. Results: European students reported that experiencing a hangover or illness, missing class, being short of money, and experiencing memory loss were the most commonly experienced negative consequences of substance use. Not living with other students and using alcohol, cannabis, sedatives, and cocaine were also associated with higher odds of experiencing these negative consequences. Conclusions: In contrast to North American data, European university students tended to experience consequences that are associated with lower level health risks rather than more severe consequences (e.g., drink-driving and physical injury). Harm prevention and reduction interventions for students should be targeted towards those consequences that are most salient to the target group to ensure feedback is relevant and potentially more effective in changing students’ substance use behaviours
Personal and Perceived Peer Use of and Attitudes Toward Alcohol Among University and College Students in Seven EU Countries: Project SNIPE.
The objective of this study was to explore perceptions of peer substance use and related attitudes among European students. Challenging perceptions about peer substance use has become the basis of a form of prevention and intervention known as the social norms approach, which can be delivered using personalized online feedback. This article reports baseline alcohol use and attitudes data for university students across Europe collected as part of the Social Norms Intervention for the prevention of Polydrug usE project (Project SNIPE)
Generalized measurements by linear elements
I give a first characterization of the class of generalized measurements that
can be exactly realized on a pair of qudits encoded in indistinguishable
particles, by using only linear elements and particle detectors. Two immediate
results follow from this characterization. (i) The Schmidt number of each POVM
element cannot exceed the number of initial particles. This rules out any
possibility of performing perfect Bell-measurements for qudits. (ii) The
maximum probability of performing a generalized incomplete Bell-measurement is
1/2.Comment: 4 pages. Submitted to Phys. Rev.
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