221 research outputs found
Mollified Moments of Cubic Dirichlet L-Functions over the Eisenstein Field
We prove, assuming the generalized Riemann Hypothesis (GRH) that the density
of the -functions associated with primitive cubic Dirichlet characters over
the Eisenstein field that do not vanish at the central point is
positive. This is achieved by computing the first mollified moment assuming a
subconvexity bound, and obtaining a sharp upper bound for the higher mollified
moments for these -functions under GRH. The proportion of non-vanishing is
explicit, but extremely small.Comment: 46 page
<i>Cocconeis molesta</i> Kütz., <i>C. diaphana</i> W.Sm. and <i>C. dirupta</i> W.Greg. (Bacillariophyta): type material, ambiguities and possible synonymies
F.T. Kützing introduced Cocconeis molesta with only an uninformative description and a poor illustration: C. molesta has small, oblong valves and is an epiphyte. Another species, Cocconeis diaphana, described by William Smith, is said to have larger valves than C. molesta, with frustules that are relatively oblong. Smith described two forms: one with a distinct fascia on its raphe valve (var. β), the other without this feature. A third species, Cocconeis dirupta was described by Gregory, who expressed doubts that it differed from C. diaphana. Finally, Cocconeis molesta var. crucifera Grunow was first introduced in Van Heurck’s Atlas but was subsequently treated by Van Heurck as a synonym of C. molesta. No previous account has examined the type material of these species. In this paper, we undertake that task and examine type slides and raw material in order to discriminate these different taxa. We conclude by recognizing three species: Cocconeis molesta Kütz., C. diaphana W.Sm. and C. dirupta W.Greg. Cocconeis diaphana var. β is considered to be a synonym of C. dirupta and C. molesta var. crucifera is considered to be a synonym of C. molesta. Lectotypes are designated for C. diaphana and C. dirupta
Ge/SiGe Quantum Well p-i-n Structures for Uncooled Infrared Bolometers
Cataloged from PDF version of article.The temperature dependence of current is
investigated experimentally for silicon–germanium (Si-Ge)
multi-quantum-well p-i-n devices on Si substrates as uncooled
bolometer active layers. Temperature coefficient of resistance
values as high as −5.8%/K are recorded. This value is
considerably higher than that of even commercial bolometer
materials in addition to being well above the previous efforts
based on CMOS compatible materials
Impacts of neighboring countries on military expenditures:A dynamic spatial panel approach
Using the latest spatial econometric techniques and data pertaining to 144 countries over the period 1993-2007, this article tests and compares four frequently used spatial econometric models and eight matrices describing the mutual relationships among the countries, all within a common framework, which helps clarify the impact of neighboring countries on military expenditures. Furthermore, it utilizes two different data sources. Due to this setup, it provides one of the most thorough spatial analyses of military expenditures so far. Furthermore, it confirms but also challenges the results of several previous studies. Military spending measured as a ratio of GDP in one country indeed depends primarily on the spending of other countries, but in a limited number of cases, it also depends on control variables that can be observed in other countries, among which are the level of GDP, the occurrence of international wars, and the political regime. The most likely specification of the matrix describing the relationships among countries is the first-order binary contiguity matrix based on land or maritime borders, extended to include two-sided relationships among the five countries that are permanent members of the UN Security Council and one-sided relationships to all other countries. Finally, cross-sectional approaches are rejected in favor of dynamic spatial panel data approaches due to their controls for habit persistence, country, and time-period fixed effects
Local differences of the position of the mental foramen
The mental foramen has been reported to vary in position in different ethnic
groups. Repeated failures during injections and operative procedures involving
the mental foramen suggest the presence of local differences in a given population.
The aim of the present study was to investigate possible local differences of
the mental foramen in Eastern Anatolian individuals in the Turkish population.
The present investigation is based on the examination of 70 adult mandibles.
The study consisted of three measurements, to include the relations of the mental
foramen to the following: 1) the lower teeth; 2) the body of mandible; 3) the
mandibular symphysis and posterior border of the ramus of the mandible.
The most common position of the foramen was in line with the longitudinal
axis of the second premolar tooth (relation IV), at the midpoint of the mandibular
body height and at 1/3.5 of the distance from the mandibular symphysis
to the posterior border of the ramus.
Local differences of the mental foramen may occur in a population. Prior to
surgery knowledge of the most common location of the foramen peculiar to
a local population may enable effective mental block anaesthesia to be provided.
(Folia Morphol 2008; 67: 32-35)
Silicon-Germanium multi-quantum well photodetectors in the near infrared
Cataloged from PDF version of article.Single crystal Silicon-Germanium multi-quantum well layers were epitaxially grown on silicon substrates. Very high quality films were achieved with high level of control utilizing recently developed MHAH epitaxial technique. MHAH growth technique facilitates the monolithic integration of photonic functionality such as modulators and photodetectors with low-cost silicon VLSI technology. Mesa structured p-i-n photodetectors were fabricated with low reverse leakage currents of ∼10 mA/cm2 and responsivity values exceeding 0.1 A/W. Moreover, the spectral responsivity of fabricated detectors can be tuned by applied voltage. © 2012 Optical Society of Americ
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