377 research outputs found
Design and operation of a prototype interaction point beam collision feedback system for the International Linear Collider
A high-resolution, intratrain position feedback system has been developed to
achieve and maintain collisions at the proposed future electron-positron
International Linear Collider (ILC). A prototype has been commissioned and
tested with a beam in the extraction line of the Accelerator Test Facility at
the High Energy Accelerator Research Organization in Japan. It consists of a
stripline beam position monitor (BPM) with analogue signal-processing
electronics, a custom digital board to perform the feedback calculation, and a
stripline kicker driven by a high-current amplifier. The closed-loop feedback
latency is 148 ns. For a three-bunch train with 154 ns bunch spacing, the
feedback system has been used to stabilize the third bunch to 450 nm. The
kicker response is linear, and the feedback performance is maintained, over a
correction range of over 60 {\mu}m. The propagation of the correction has
been confirmed by using an independent stripline BPM located downstream of the
feedback system. The system has been demonstrated to meet the BPM resolution,
beam kick, and latency requirements for the ILC
Wingless and intermorphic males in the ant Cardiocondyla venustula
The ant genus Cardiocondyla is characterized by a pronounced male diphenism with
wingless fighter males and winged disperser males. Winged males have been lost convergently in at
least two species-rich clades. Here, we describe the morphological variability of males of C. venustula
from uThukela valley, South Africa. Winged males appear to be absent from this species. However, in
addition to wingless (āergatoidā) males with widely fused thoracic sutures and without ocelli,
āintermorphicā males exist that combine the typical morphology of wingless males with
characteristics of winged males, e.g., more pronounced thoracic sutures, rudimentary ocelli, and
vestigial wings. Similar āintermorphicā males have previously been described from one of several
genetically distinct lineages of the Southeast Asian āC. kagutsuchiā complex (Yamauchi et al., 2005).
To determine whether male morphology is associated with distinct clades also in C. venustula, we
sequenced a 631 bp fragment of mitochondrial DNA of workers from 13 colonies. We found six
haplotypes with a sequence variation of up to 5.7%. Intermorphic and wingless males did not appear
to be associated with a particular of these lineages and within colonies showed the same sequence.
Interestingly, two colonies contained workers with different haplotypes, suggesting the occasional
migration of queens and / or workers between colonies.Financial support came from Deutsche Forschungsgemeinschaft (He 1623/32 and He 1623/34).http://www.springerlink.com/content/101198/?p=d05a2cfd29ea4cf1b64b48ed3302b001&pi=906hb2013ab201
Precise Charm- and Bottom-Quark Masses: Theoretical and Experimental Uncertainties
Recent theoretical and experimental improvements in the determination of
charm and bottom quark masses are discussed. A new and improved evaluation of
the contribution from the gluon condensate to the
charm mass determination and a detailed study of potential uncertainties in the
continuum cross section for production is presented, together with a
study of the parametric uncertainty from the -dependence of our
results. The final results, MeV and
MeV, represent, together with a closely related lattice
determination MeV, the presently most precise
determinations of these two fundamental Standard Model parameters. A critical
analysis of the theoretical and experimental uncertainties is presented.Comment: 12 pages, presented at Quarks~2010, 16th International Seminar of
High Energy Physics, Kolomna, Russia, June 6-12, 2010; v2: references adde
PARP1 suppresses homologous recombination events in mice in vivo
Recent studies suggest that PARP1 inhibitors, several of which are currently in clinical trial, may selectively kill BRCA1/2 mutant cancers cells. It is thought that the success of this therapy is based on immitigable lethal DNA damage in the cancer cells resultant from the concurrent loss or inhibition of two DNA damage repair pathways: single-strand break (SSB) repair and homologous recombination repair (HRR). Presumably, inhibition of PARP1 activity obstructs the repair of SSBs and during DNA replication, these lesions cause replication fork collapse and are transformed into substrates for HRR. In fact, several previous studies have indicated a hyper-recombinogenic phenotype in the absence of active PARP1 in vitro or in response to DNA damaging agents. In this study, we demonstrate an increased frequency of spontaneous HRR in vivo in the absence of PARP1 using the pun assay. Furthermore, we found that the HRR events that occur in Parp1 nullizygous mice are associated with a significant increase in large, clonal events, as opposed to the usually more frequent single cell events, suggesting an effect in replicating cells. In conclusion, our data demonstrates that PARP1 inhibits spontaneous HRR events, and supports the model of DNA replication transformation of SSBs into HRR substrates
Higgs and non-universal gaugino masses: no SUSY signal expected yet?
So far, no supersymmetric particles have been detected at the Large Hadron
Collider (LHC). However, the recent Higgs results have interesting implications
for the SUSY parameter space. In this paper, we study the consequences of an
LHC Higgs signal for a model with non-universal gaugino masses in the context
of SU(5) unification. The gaugino mass ratios associated with the higher
representations produce viable spectra that are largely inaccessible to the
current LHC and direct dark matter detection experiments. Thus, in light of the
Higgs results, the non-observation of SUSY is no surprise.Comment: supplementary file containing plots with log priors in ancillary
files. v2: added some comments on more general settings and references,
accepted for publication in JHE
Widespread detection of highly pathogenic H5 influenza viruses in wild birds from the Pacific Flyway of the United States
A novel highly pathogenic avian influenza virus belonging to the H5 clade 2.3.4.4 variant viruses was detected in North America in late 2014. Motivated by the identification of these viruses in domestic poultry in Canada, an intensive study was initiated to conduct highly pathogenic avian influenza surveillance in wild birds in the Pacific Flyway of the United States. A total of 4,729 hunter-harvested wild birds were sampled and highly pathogenic avian influenza virus was detected in 1.3% (n = 63). Three H5 clade 2.3.4.4 subtypes were isolated from wild birds, H5N2, H5N8, and H5N1, representing the wholly Eurasian lineage H5N8 and two novel reassortant viruses. Testing of 150 additional wild birds during avian morbidity and mortality investigations in Washington yielded 10 (6.7%) additional highly pathogenic avian influenza isolates (H5N8 = 3 and H5N2 = 7). The geographically widespread detection of these viruses in apparently healthy wild waterfowl suggest that the H5 clade 2.3.4.4 variant viruses may behave similarly in this taxonomic group whereby many waterfowl species are susceptible to infection but do not demonstrate obvious clinical disease. Despite these findings in wild waterfowl, mortality has been documented for some wild bird species and losses in US domestic poultry during the first half of 2015 were unprecedented
Does the Time Inconsistency Problem Make Flexible Exchange Rates Look Worse than You Think?
The Human Phenotype Ontology in 2024: phenotypes around the world
The Human Phenotype Ontology (HPO) is a widely used resource that comprehensively organizes and defines the phenotypic features of human disease, enabling computational inference and supporting genomic and phenotypic analyses through semantic similarity and machine learning algorithms. The HPO has widespread applications in clinical diagnostics and translational research, including genomic diagnostics, gene-disease discovery, and cohort analytics. In recent years, groups around the world have developed translations of the HPO from English to other languages, and the HPO browser has been internationalized, allowing users to view HPO term labels and in many cases synonyms and definitions in ten languages in addition to English. Since our last report, a total of 2239 new HPO terms and 49235 new HPO annotations were developed, many in collaboration with external groups in the fields of psychiatry, arthrogryposis, immunology and cardiology. The Medical Action Ontology (MAxO) is a new effort to model treatments and other measures taken for clinical management. Finally, the HPO consortium is contributing to efforts to integrate the HPO and the GA4GH Phenopacket Schema into electronic health records (EHRs) with the goal of more standardized and computable integration of rare disease data in EHRs
- ā¦