690 research outputs found
On stirling numbers of the second kind
AbstractWe first find inequalities between the Stirling numbers S(n, r) for fixed n, then introduce functions L and U such that L(n, r)≤S(n, r)≤U(n, r), and finally obtain the asymptotic value n/log n for the value of r for which S(n, r) is maximal
Collisionless hydrodynamics for 1D motion of inhomogeneous degenerate electron gases: equivalence of two recent descriptions
Recently I. Tokatly and O. Pankratov (''TP'', Phys. Rev. B 60, 15550 (1999))
used velocity moments of a semiclassical kinetic equation to derive a
hydrodynamic description of electron motion in a degenerate electron gas.
Independently, the present authors (Theochem 501-502, 327 (2000)) used
considerations arising from the Harmonic Potential Theorem (Phys. Rev. Lett.
73, 2244 (1994)) to generate a new form of high-frequency hydrodynamics for
inhomogeneous degenerate electron gases (HPT-N3 hydrodynamics). We show here
that TP hydrodynamics yields HPT-N3 hydrodynamics when linearized about a
Thomas-Fermi groundstate with one-dimensional spatial inhomnogeneity.Comment: 17p
Eimeria chinchillae De Vos & Van der Westhuizen, 1968 and other Eimeria spp. from three South African rodent species
Eimeria chinchillae De Vos & Van der Westhuizen, 1968, an organism originally described from the chinchilla and subsequently shown to be transmissible to other rodents, was found to occur naturally in Rhabdomys pumilio (Sparrman, 1784) in South Africa. The morphology of the oocysts, the site of development of the endogenous stages and the prepatent period of the infection were similar to those of E. chinchillae obtained from chinchillas and transmitted experimentally to R. pumilio. The identity of the organism was confirmed by the successful infection of chinchillas. Three additional Eimeria spp. were found in R. pumilio. Oocysts of Eimeria pumilioi n. sp. measured 18 by 12 µ, those of Eimeria rhabdomyis n. sp., 13 by 12 µ and those of Eimeria pretoriensis n. sp., 24 by 19 µ. Two Eimeria spp. were also found in Praomys (Mastomys) natalensis (Smith, 1834). Oocysts of Eimeria mastomyis n. sp. measured 27 by 21 µ and those of Eimeria theileri n. sp. 20 by 17 µ. A single Eimeria sp., Eimeria otomyis n. sp., was found in Otomys irroratus (Brants, 1827). The oocysts measured 20 by 15 µ.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format..mn201
Distributed Generation and Resilience in Power Grids
We study the effects of the allocation of distributed generation on the
resilience of power grids. We find that an unconstrained allocation and growth
of the distributed generation can drive a power grid beyond its design
parameters. In order to overcome such a problem, we propose a topological
algorithm derived from the field of Complex Networks to allocate distributed
generation sources in an existing power grid.Comment: proceedings of Critis 2012 http://critis12.hig.no
Microfluidics for Small-Angle X-ray Scattering
Small-angle X-ray scattering is a well-established biophysical technique, whilst micro-fluidics is proving to be a convenient technology for creating miniaturised multifunctional devices. Both fields are highly versatile and find use in multiple scientific disciplines. Together, they offer the potential to obtain structural information on biomacromolecules, nanoparticles and condensed matter, in a high-throughput manner and with enhanced time-resolution capabilities. This chapter provides practical design considerations for X-ray-based microfluidic systems and examines some of the existing microfluidic platforms used in conjunction with small-angle X-ray scattering. As the exclusive advantages of microfluidics become recognised and accessible, the prevalence of microfluidic sample environments in X-ray scattering measurements will hopefully increase
Statistical inaccuracies over use of facial skin care products and sunscreens in the aetiology of frontal fibrosing alopecia: reply from authors.
We did not perform a matched one-to-one comparison between FFA subjects and controls, we compared two groups with similar ages. The only continuous variable was age. The responses to the questions posed were categorical. We therefore maintain that a Fisher's exact test rather than a McNemar's test was an appropriate method for analyzing the results
The SF3B1 inhibitor spliceostatin A (SSA) elicits apoptosis in chronic lymphocytic leukemia cells through downregulation of Mcl-1
The pro-survival Bcl-2 family member Mcl-1 is expressed in chronic lymphocytic leukemia (CLL), with high expression correlated with progressive disease. The spliceosome inhibitor spliceostatin A (SSA), is known to regulate Mcl-1 and so here we assessed the ability of SSA to elicit apoptosis in CLL. SSA induced apoptosis of CLL cells at low nanomolar concentrations in a dose- and time-dependent manner, but independently of SF3B1 mutational status, IGHV status and CD38 or ZAP70 expression. However, normal B and T cells were less sensitive than CLL cells (P=0.006 and P<0.001, respectively). SSA altered the splicing of anti-apoptotic MCL-1L to MCL-1s in CLL cells coincident with induction of apoptosis. Overexpression studies in Ramos cells suggested Mcl-1 was important for SSA-induced killing since its expression inversely correlated with apoptosis (P=0.001). IL4 and CD40L, present in patient lymph nodes, are known to protect tumor cells from apoptosis and significantly inhibited SSA, ABT-263 and ABT-199 induced killing following administration to CLL cells (P=0.008). However, by combining SSA with the Bcl-2/Bcl-xL antagonists ABT-263 or ABT-199, we were able to overcome this pro-survival effect. We conclude that SSA combined with Bcl-2/Bcl-xL antagonists may have therapeutic utility for CL
Spin Resolution of the Electron-Gas Correlation Energy: Positive same-spin contribution
The negative correlation energy per particle of a uniform electron gas of
density parameter and spin polarization is well known, but its
spin resolution into up-down, up-up, and down-down contributions is not.
Widely-used estimates are incorrect, and hamper the development of reliable
density functionals and pair distribution functions. For the spin resolution,
we present interpolations between high- and low-density limits that agree with
available Quantum Monte Carlo data. In the low-density limit for ,
we find that the same-spin correlation energy is unexpectedly positive, and we
explain why. We also estimate the up and down contributions to the kinetic
energy of correlation.Comment: new version, to appear in PRB Rapid Communicatio
Genomic Deletion Marking an Emerging Subclone of Francisella tularensis subsp. holarctica in France and the Iberian Peninsula
P. 7465-7470Francisella tularensis subsp. holarctica is widely disseminated in North America and the boreal and temperate
regions of the Eurasian continent. Comparative genomic analyses identified a 1.59-kb genomic deletion specific
to F. tularensis subsp. holarctica isolates from Spain and France. Phylogenetic analysis of strains carrying this
deletion by multiple-locus variable-number tandem repeat analysis showed that the strains comprise a highly
related set of genotypes, implying that these strains were recently introduced or recently emerged by clonal
expansion in France and the Iberian PeninsulaS
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