603 research outputs found
The a-number of hyperelliptic curves
It is known that for a smooth hyperelliptic curve to have a large -number,
the genus must be small relative to the characteristic of the field, ,
over which the curve is defined. It was proven by Elkin that for a genus
hyperelliptic curve to have , the genus is bounded by
. In this paper, we show that this bound can be lowered to . The method of proof is to force the Cartier-Manin matrix to have rank one
and examine what restrictions that places on the affine equation defining the
hyperelliptic curve. We then use this bound to summarize what is known about
the existence of such curves when and .Comment: 7 pages. v2: revised and improved the proof of the main theorem based
on suggestions from the referee. To appear in the proceedings volume of Women
in Numbers Europe-
Large Silicon Abundance in Photodissociation Regions
We have made one-dimensional raster-scan observations of the rho Oph and
sigma Sco star-forming regions with two spectrometers (SWS and LWS) on board
the ISO. In the rho Oph region, [SiII] 35um, [OI] 63um, 146um, [CII] 158um, and
the H2 pure rotational transition lines S(0) to S(3) are detected, and the PDR
properties are derived as the radiation field scaled by the solar neighborhood
value G_0~30-500, the gas density n~250--2500 /cc, and the surface temperature
T~100-400 K. The ratio of [SiII] 35um to [OI] 146um indicates that silicon of
10--20% of the solar abundance must be in the gaseous form in the
photodissociation region (PDR), suggesting that efficient dust destruction is
undergoing even in the PDR and that part of silicon atoms may be contained in
volatile forms in dust grains. The [OI] 63um and [CII] 158um emissions are too
weak relative to [OI] 146um to be accounted for by standard PDR models. We
propose a simple model, in which overlapping PDR clouds along the line of sight
absorb the [OI] 63um and [CII] 158um emissions, and show that the proposed
model reproduces the observed line intensities fairly well. In the sigma Sco
region, we have detected 3 fine-structure lines, [OI] 63um, [NII] 122um, and
[CII] 158um, and derived that 30-80% of the [CII] emission comes from the
ionized gas. The upper limit of the [SiII] 35um is compatible with the solar
abundance relative to nitrogen and no useful constraint on the gaseous Si is
obtained for the sigma Sco region.Comment: 25 pages with 7 figures, accepted in Astrophysical Journa
Notch signaling during human T cell development
Notch signaling is critical during multiple stages of T cell development in both mouse and human. Evidence has emerged in recent years that this pathway might regulate T-lineage differentiation differently between both species. Here, we review our current understanding of how Notch signaling is activated and used during human T cell development. First, we set the stage by describing the developmental steps that make up human T cell development before describing the expression profiles of Notch receptors, ligands, and target genes during this process. To delineate stage-specific roles for Notch signaling during human T cell development, we subsequently try to interpret the functional Notch studies that have been performed in light of these expression profiles and compare this to its suggested role in the mouse
PII S0016-7037(02)00844-X Low ␦ 18 O zircons, U-Pb dating, and the age of the Qinglongshan oxygen and hydrogen isotope anomaly near Donghai in Jiangsu Province, China
Abstract-Zircons 18 O values were imprinted on the rocks by a hydrothermal system charged with meteoric water from a cold climate. Groundwater circulation was driven by heat from cooling granitic magma. The geologic age of the hydrothermal system correlates with that of the Nantuo tillite in the Sinian strata of the South China block, suggesting that Qinglongshan's cold climate may be a manifestation of Neoproterozoic "snowball Earth."
Asynchronous combinatorial action of four regulatory factors activates Bcl11b for T cell commitment
During T cell development, multipotent progenitors relinquish competence for other fates and commit to the T cell lineage by turning on Bcl11b, which encodes a transcription factor. To clarify lineage commitment mechanisms, we followed developing T cells at the single-cell level using Bcl11b knock-in fluorescent reporter mice. Notch signaling and Notch-activated transcription factors collaborate to activate Bcl11b expression irrespectively of Notch-dependent proliferation. These inputs work via three distinct, asynchronous mechanisms: an early locus 'poising' function dependent on TCF-1 and GATA-3, a stochastic-permissivity function dependent on Notch signaling, and a separate amplitude-control function dependent on Runx1, a factor already present in multipotent progenitors. Despite their necessity for Bcl11b expression, these inputs act in a stage-specific manner, providing a multitiered mechanism for developmental gene regulation
901-2 Randomized, Double-Blind Multicenter Trial of a Novel Modified t-PA, E6010 by i.v. Bolus Injection in Treatment of Acute Myocardial Infarction (AMI) – Comparison with Native t-PA
E6010 is a novel modified t-PA, in which cysteine 84 in the epidermal growth factor domain has been replaced by serine. This is the first modified t-PA to be effective by i.v. bolus injection, and it has a prolonged half-life (Tα1/2 > 20 min) compared to native t-PA.A randomized, double-blind multicenter trial of i.v. bolus injection of E601 0, 27,500 EU/kg, compared with native t-PA (cell culture), 14,400,000 IU has been performed in the treatment of AMI of ≤ 6 hr duration and total occlusion of the infarct-related arteries. Angiograms were used to evaluate the patency of infarct-related arteries at 15, 30, 45, and 60 minutes after the administration.Result% Recanalization Rate (TIMI grade 2 or 3)15min.30min.45min60min.E6010n = 9736.561.973.779.4native t-PAn = 10213.732.449.564.7The time to reperfusion with E601 0 was shorter than that with native t-PA. Coronary recanalization at 30 and 60 minutes after administration was obtained in 61.9% and 79.4% of the case with E6010 and in 32.4% and 64.7% of the case with native t-PA, and the difference between both were statistically significant. No fatal bleeding complications were observed in E601 0.4 patients (3.8%) in E6010 and 3 patients (2.8%) in native t-PA died during 48 days post treatment hospitalization.Discussion and ConclusionNative t-PA is required to be administered over period of 1 hr with 10% of the total dose administered as an i.v. bolus and the remainder infused i.v. over 1 hr. Our present results indicate that E601 0 can be easily administered by i.v. bolus injection taking 2–3 minutes and it exerts a valuable thrombolytic effects, namely a high rate and early recanalization of infarct-related arterie
The UNITE database for molecular identification and taxonomic communication of fungi and other eukaryotes : sequences, taxa and classifications reconsidered
Acknowledgements We acknowledge Marie Zirk for her work in designing the UNITE logotype and creating the visual abstract for this article. Funding UNITE database development is financed by the Estonian Research Council [PRG1170]; European Union's Horizon 2020 project BGE [101059492]. The PlutoF digital infrastructure is supported by the European Union's Horizon 2020 project BiCIKL [101007492]; Estonian Research Infrastructure roadmap project DiSSCo Estonia. Funding for open access charge: UNITE Community. Conflict of interest statement. None declared.Peer reviewedPublisher PD
Substance-Related Health Problems during Rave Parties in the Netherlands (1997–2008)
The objective of this study was to describe a 12-year (1997–2008) observation of substance-related incidents occurring at rave parties in the Netherlands, including length of visits to first-aid stations, substances used, and severity of the incidents. During rave parties, specifically trained medical and paramedical personnel staffed first aid stations. Visitors were diagnosed and treated, and their data were recorded using standardized methods. During the 12-year period with 249 rave parties involving about 3,800,000 visitors, 27,897 people visited a first aid station, of whom 10,100 reported having a substance-related problem. The mean age of these people was 22.3+/−5.4 years; 52.4% of them were male. Most (66.7%) substance-related problems were associated with ecstasy or alcohol use or both. Among 10,100 substance-related cases, 515 required professional medical care, and 16 of these cases were life threatening. People with a substance-related problem stayed 20 min at the first aid station, which was significantly longer than the 5 min that those without a substance-related health problem stayed. These unique data from the Netherlands identify a variety of acute health problems related to the use of alcohol, amphetamines, cannabis, cocaine, ecstasy, and GHB. Although most problems were minor, people using GHB more often required professional medical care those using the other substances. We recommended adherence to harm and risk reduction policy, and the use of first aid stations with specially trained staff for both minor and serious incidents
- …