322 research outputs found
Responses to comments and elaborations of previous posts III
This post is dedicated to the memory of Rabbi Chaim Flom, late rosh yeshiva of Yeshivat Ohr David in Jerusalem. I first met Rabbi Flom thirty years ago when he became my teacher at the Hebrew Youth Academy of Essex County (now known as the Joseph Kushner Hebrew Academy; unfortunately, another one of my teachers from those years also passed away much too young, Rabbi Yaakov Appel). When he first started teaching he was known as Mr. Flom, because he hadn't yet received semikhah (Actually, he had some sort of semikhah but he told me that he didn't think it was adequate to be called "Rabbi" by the students.) He was only at the school a couple of years and then decided to move to Israel to open his yeshiva. I still remember his first parlor meeting which was held at my house. Rabbi Flom was a very special man. Just to give some idea of this, ten years after leaving the United States he was still in touch with many of the students and even attended our weddings. He would always call me when he came to the U.S. and was genuinely interested to hear about my family and what I was working on. He will be greatly missed
Symmetry, dimension and the distribution of the conductance at the mobility edge
The probability distribution of the conductance at the mobility edge,
, in different universality classes and dimensions is investigated
numerically for a variety of random systems. It is shown that is
universal for systems of given symmetry, dimensionality, and boundary
conditions. An analytical form of for small values of is discussed
and agreement with numerical data is observed. For , is
proportional to rather than .Comment: 4 pages REVTeX, 5 figures and 2 tables include
DMAPT inhibits NF-κB activity and increases sensitivity of prostate cancer cells to X-rays in vitro and in tumor xenografts in vivo
Constitutive activation of the pro-survival transcription factor NF-κB has been associated with resistance to both chemotherapy and radiation therapy in many human cancers, including prostate cancer. Our lab and others have demonstrated that the natural product parthenolide can inhibit NF-κB activity and sensitize PC-3 prostate cancers cells to X-rays in vitro; however, parthenolide has poor bioavailability in vivo and therefore has little clinical utility in this regard. We show here that treatment of PC-3 and DU145 human prostate cancer cells with dimethylaminoparthenolide (DMAPT), a parthenolide derivative with increased bioavailability, inhibits constitutive and radiation-induced NF-κB binding activity and slows prostate cancer cell growth. We also show that DMAPT increases single and fractionated X-ray-induced killing of prostate cancer cells through inhibition of DNA double strand break repair and also that DMAPT-induced radiosensitization is, at least partially, dependent upon the alteration of intracellular thiol reduction-oxidation chemistry. Finally, we demonstrate that the treatment of PC-3 prostate tumor xenografts with oral DMAPT in addition to radiation therapy significantly decreases tumor growth and results in significantly smaller tumor volumes compared to xenografts treated with either DMAPT or radiation therapy alone, suggesting that DMAPT might have a potential clinical role as a radiosensitizing agent in the treatment of prostate cancer
Distributed transactional reads: the strong, the quick, the fresh & the impossible
International audienceThis paper studies the costs and trade-offs of providing transactional consistent reads in a distributed storage system. We identify the following dimensions: read consistency, read delay (latency), and data freshness. We show that there is a three-way trade-off between them, which can be summarised as follows: (i) it is not possible to ensure at the same time order-preserving (e.g., causally-consistent) or atomic reads, Minimal Delay, and maximal freshness; thus, reading data that is the most fresh without delay is possible only in a weakly-isolated mode; (ii) to ensure atomic or order-preserving reads at Minimal Delay imposes to read data from the past (not fresh); (iii) however, order-preserving minimal-delay reads can be fresher than atomic; (iv) reading atomic or order-preserving data at maximal freshness may block reads or writes indefinitely. Our impossibility results hold independently of other features of the database, such as update semantics (totally ordered or not) or data model (structured or unstructured). Guided by these results, we modify an existing protocol to ensure minimal-delay reads (at the cost of freshness) under atomic-visibility and causally-consistent semantics. Our experimental evaluation supports the theoretical results
The DiskMass Survey. II. Error Budget
We present a performance analysis of the DiskMass Survey. The survey uses
collisionless tracers in the form of disk stars to measure the surface-density
of spiral disks, to provide an absolute calibration of the stellar
mass-to-light ratio, and to yield robust estimates of the dark-matter halo
density profile in the inner regions of galaxies. We find a disk inclination
range of 25-35 degrees is optimal for our measurements, consistent with our
survey design to select nearly face-on galaxies. Uncertainties in disk
scale-heights are significant, but can be estimated from radial scale-lengths
to 25% now, and more precisely in the future. We detail the spectroscopic
analysis used to derive line-of-sight velocity dispersions, precise at low
surface-brightness, and accurate in the presence of composite stellar
populations. Our methods take full advantage of large-grasp integral-field
spectroscopy and an extensive library of observed stars. We show that the
baryon-to-total mass fraction (F_b) is not a well-defined observational
quantity because it is coupled to the halo mass model. This remains true even
when the disk mass is known and spatially-extended rotation curves are
available. In contrast, the fraction of the rotation speed supplied by the disk
at 2.2 scale lengths (disk maximality) is a robust observational indicator of
the baryonic disk contribution to the potential. We construct the error-budget
for the key quantities: dynamical disk mass surface-density, disk stellar
mass-to-light ratio, and disk maximality (V_disk / V_circular). Random and
systematic errors in these quantities for individual galaxies will be ~25%,
while survey precision for sample quartiles are reduced to 10%, largely devoid
of systematic errors outside of distance uncertainties.Comment: To appear in ApJ; 88 pages, 4 tables, 18 figures. High-resolution
version available at
http://www.astro.wisc.edu/~mab/publications/DMS_II_preprint.pd
Ancient papillomavirus-host co-speciation in Felidae
The evolutionary rate of feline papillomaviruses is inferred from the phylogenetic analysis of their hosts, providing evidence for long-term virus-host co-speciatio
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