6,182 research outputs found
Alien Registration- La Pierre, Leo J. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/21838/thumbnail.jp
Polynomial growth of volume of balls for zero-entropy geodesic systems
The aim of this paper is to state and prove polynomial analogues of the
classical Manning inequality relating the topological entropy of a geodesic
flow with the growth rate of the volume of balls in the universal covering. To
this aim we use two numerical conjugacy invariants, the {\em strong polynomial
entropy } and the {\em weak polynomial entropy }. Both are
infinite when the topological entropy is positive and they satisfy
. We first prove that the growth rate of the volume of
balls is bounded above by means of the strong polynomial entropy and we show
that for the flat torus this inequality becomes an equality. We then study the
explicit example of the torus of revolution for which we can give an exact
asymptotic equivalent of the growth rate of volume of balls, which we relate to
the weak polynomial entropy.Comment: 22 page
An orchestrated intron retention program in meiosis controls timely usage of transcripts during germ cell differentiation
Global transcriptome reprogramming during sper-matogenesis ensures timely expression of factors in each phase of male germ cell differentiation. Sper-matocytes and spermatids require particularly exten-sive reprogramming of gene expression to switch from mitosis to meiosis and to support gamete morphogenesis. Here, we uncovered an extensive alternative splicing program during this transmeiotic differentiation. Notably, intron retention was largely the most enriched pattern, with spermatocytes showing generally higher levels of retention compared with spermatids. Retained introns are characterized by weak splice sites and are enriched in genes with strong relevance for gamete func-tion. Meiotic intron-retaining transcripts (IRTs) were exclusively localized in the nucleus. However, differ-ently from other developmentally regulated IRTs, they are stable RNAs, showing longer half-life than properly spliced transcripts. Strikingly, fate-mapping experiments revealed that IRTs are recruited onto polyribosomes days after synthesis. These studies reveal an unexpected function for regulated intron retention in modulation of the timely expression of select transcripts during spermatogenesis
Influence of the substrate type on CVD grown homoepitaxial diamond layer quality by cross sectional TEM and CL analysis
To assess diamond-based semiconducting devices, a reduction of point defect levels and an accurate control of doping are required as well as the control of layer thickness. Among the analyses required to improve such parameters, cross sectional studies should take importance in the near future. The present contribution shows
how FIB (focused ion beam) preparations followed by electron microscopy related techniques as TEM or CL allowed to performanalysis versus depth in the layer, doping and point defect levels. Three samples grown along the sameweek in the same machinewith identical growth conditions but on different substrates (CVD-IIIa (110)
oriented, CVD-optical grade (100) oriented and a HPHT-Ib (100) oriented) are studied. Even though A-band is observed by CL, no dislocation is observed by CTEM. Point defect type and level are shown to substantially change with respect to the substrate type as well as the boron doping levels that vary within an order of magnitude. H3 present in the epilayer grown on HPHT type of substrate is replaced by T1 and NE3 point defects for epilayers grown on the CVD type one. An increase of excitonic transitions through LO phonons is also shown to take place near the surface while only TO ones are detected deeper in the epilayer. Such results highlight the importance of choosing the correct substrate.5 page
Freeze-Dried Ham Promotes Azoxymethane-Induced Mucin-Depleted Foci and Aberrant Crypt Foci in Rat Colon
Processed and red meat consumption is associated with the risk of colorectal cancer. Meta-analyses have suggested that the risk associated with processed meat is higher. Most processed meats are cured and cooked, which leads to formation of free nitrosyl heme. We speculated that free nitrosyl heme is more toxic than native myoglobin. The promoting effect of a freeze-dried, cooked, cured ham diet was looked for in a 100-day study. Colon carcinogenesis endpoints were aberrant crypt foci and mucin depleted foci (MDF). A second study (14 days) was designed 1) to compare the effect of ham, hemoglobin, and hemin; and 2) to test the effect of sodium chloride, nitrite, and phosphate in diet on early biomarkers associated with heme-induced promotion. In the 100-day study, control and ham-fed rats had 3.5 and 8.5 MDF/colon, respectively (P < 0.0001). Promotion was associated with cytotoxicity and lipid peroxidation. In the short-term study, cytotoxicity and lipid peroxidation of fecal water, and the urinary marker of lipid peroxidation, increased dramatically in ham- and hemin-fed rat. In contrast, the hemoglobin diet, sodium chloride, nitrite, phosphate diet had no effect. Freeze-dried cooked ham can promote colon carcinogenesis in a rodent model. Hemin, but not hemoglobin, mimicked ham effect on early biochemical markers associated with carcinogenesis
On the initial estimate of interface forces in FETI methods
The Balanced Domain Decomposition (BDD) method and the Finite Element Tearing
and Interconnecting (FETI) method are two commonly used non-overlapping domain
decomposition methods. Due to strong theoretical and numerical similarities,
these two methods are generally considered as being equivalently efficient.
However, for some particular cases, such as for structures with strong
heterogeneities, FETI requires a large number of iterations to compute the
solution compared to BDD. In this paper, the origin of the bad efficiency of
FETI in these particular cases is traced back to poor initial estimates of the
interface stresses. To improve the estimation of interface forces a novel
strategy for splitting interface forces between neighboring substructures is
proposed. The additional computational cost incurred is not significant. This
yields a new initialization for the FETI method and restores numerical
efficiency which makes FETI comparable to BDD even for problems where FETI was
performing poorly. Various simple test problems are presented to discuss the
efficiency of the proposed strategy and to illustrate the so-obtained numerical
equivalence between the BDD and FETI solvers
Characterization of the pressure losses in a common rail diesel injector
A methodology to characterise the pressure losses in quasi-steady conditions (i.e. at
full needle lift) of common rail diesel injectors was developed. The aim was to quantify the
error when experimental results of nozzle internal flow are compared with CFD results,
where pressure losses are usually neglected. The proposed methodology is based mainly on
experimental tests that are complemented with some approximate calculations, based on
the physics of the phenomenon, to take into account the effect of the needle deformation.
The results obtained in the work lead to two important conclusions: on the one hand,
that it is dangerous to extrapolate results relative to the injection (internal flow, spray
atomization, spray penetrationË
..) and combustion processes from low permeability nozzles
(e.g. single-hole nozzles) to high permeability nozzles (e.g. multi-hole nozzles), and,
on the other hand, that the comparison of these results between experiments and CFD
simulations should be carried out carefully, because the pressure losses in the injector can
be high under certain conditions. Finally, people working on the study of the injection
and/or combustion processes, through experiments or simulations, will find here some
interesting information to better know the actual injection pressure to be used in their
analysis and/or simulations.The PhD studies of Oscar A. de la Garza were funded by the FPU program of the Ministerio de Educacion of Spain (grant no. AP2008-01913).LĂłpez, JJ.; Salvador Rubio, FJ.; De La Garza De Leon, O.; Arregle, JJP. (2012). Characterization of the pressure losses in a common rail diesel injector. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. 226(12):1697-1706. https://doi.org/10.1177/0954407012447020S169717062261
The influence of Ga-irradiation on the transport properties of mesoscopic conducting thin films
We studied the influence of 30keV Ga-ions -- commonly used in focused ion
beam (FIB) devices -- on the transport properties of thin crystalline graphite
flake, LaCaMnO and Co thin films. The changes of the
electrical resistance were measured in-situ during irradiation and also the
temperature and magnetic field dependence before and after irradiation. Our
results show that the transport properties of these materials strongly change
at Ga fluences much below those used for patterning and ion beam induced
deposition (IBID), limiting seriously the use of FIB when the intrinsic
properties of the materials of interest are of importance. We present a method
that can be used to protect the sample as well as to produce selectively
irradiation-induced changes.Comment: 14 pages, 11 figures, will be published in Nanotechnology 201
Mimivirus in Pneumonia Patients
Mimivirus, the largest virus known to date, is an amebal pathogen like Legionella spp. When mimivirus was used as an antigen in a migration inhibition factor assay, seroconversion was found in patients with both community- and hospital-acquired pneumonia. Mimivirus DNA was found in respiratory samples of patients with hospital-acquired pneumonia
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