1,513 research outputs found
Impaired H-Reflex Adaptations Following Slope Walking in Individuals With Post-stroke Hemiparesis
Background and Purpose: Short term adaptations in the Ia afferent-motoneuron pathway, as measured using the H-reflex, in response to altered ground reaction forces (GRFs) applied at the feet during slope walking have been observed in the non-impaired nervous system. The ability of the stroke-impaired nervous system to adapt to altered GRFs have not been examined. The purpose of this study was to examine the acute effects of altered propulsive and braking forces applied at the feet, which naturally occurs when walking on different slopes, on adaptations of the H-reflex pathway in individuals with chronic post-stroke hemiparesis
Host and viral mechanisms of congenital Zika syndrome
In 2015-2016, in the Americas, and especially in northeast Brazil, a significant number of cases of microcephaly and other congenital brain abnormalities were linked with an outbreak of Zika virus (ZIKV) infection in pregnant women. While maternal symptoms of ZIKV are generally mild and self-limiting, clinical presentation in fetuses and newborns infected is extensive and includes microcephaly, decreased cortical development, atrophy and hypoplasia of the cerebellum and cerebellar vermis, arthrogryposis, and polyhydramnios. The term congenital ZIKV syndrome (CZS) was introduced to describe the range of findings associated with maternal-fetal ZIKV transmission. ZIKV is primarily transmitted b
LASER: Light, Accurate Sharing dEtection and Repair
Contention for shared memory, in the forms of true sharing and false sharing, is a challenging performance bug to discover and to repair. Understanding cache contention requires global knowledge of the program\u27s actual sharing behavior, and can even arise invisibly in the program due to the opaque decisions of the memory allocator. Previous schemes have focused only on false sharing, and impose significant performance penalties or require non-trivial alterations to the operating system or runtime system environment.
This paper presents the Light, Accurate Sharing dEtection and Repair (LASER) system, which leverages new performance counter capabilities available on Intel\u27s Haswell architecture that identify the source of expensive cache coherence events. Using records of these events generated by the hardware, we build a system for online contention detection and repair that operates with low performance overhead and does not require any invasive program, compiler or operating system changes. Our experiments show that LASER imposes just 2% average runtime overhead on the Phoenix, Parsec and Splash2x benchmarks. LASER can automatically improve the performance of programs by up to 19% on commodity hardware
The Effect of Condensates on the Characterization of Transiting Planet Atmospheres with Transmission Spectroscopy
Through a simple physical argument we show that the slant optical depth
through the atmosphere of a "hot Jupiter" planet is 35-90 times greater than
the normal optical depth. This not unexpected result has direct consequences
for the method of transmission spectroscopy for characterizing the atmospheres
of transiting giant planets. The atmospheres of these planets likely contain
minor condensates and hazes which at normal viewing geometry have negligible
optical depth, but at slant viewing geometry have appreciable optical depth
that can obscure absorption features of gaseous atmospheric species. We
identify several possible condensates. We predict that this is a general
masking mechanism for all planets, not just for HD 209458b, and will lead to
weaker than expected or undetected absorption features. Constraints on an
atmosphere from transmission spectroscopy are not the same as constraints on an
atmosphere at normal viewing geometry.Comment: 6 pages. MNRAS, in press. New version fixes some incorrect numbers in
Table 1. References update
Rhomboid family member 2 regulates cytoskeletal stress-associated Keratin 16.
Keratin 16 (K16) is a cytoskeletal scaffolding protein highly expressed at pressure-bearing sites of the mammalian footpad. It can be induced in hyperproliferative states such as wound healing, inflammation and cancer. Here we show that the inactive rhomboid protease RHBDF2 (iRHOM2) regulates thickening of the footpad epidermis through its interaction with K16. K16 expression is absent in the thinned footpads of irhom2-/- mice compared with irhom2+/+mice, due to reduced keratinocyte proliferation. Gain-of-function mutations in iRHOM2 underlie Tylosis with oesophageal cancer (TOC), characterized by palmoplantar thickening, upregulate K16 with robust downregulation of its type II keratin binding partner, K6. By orchestrating the remodelling and turnover of K16, and uncoupling it from K6, iRHOM2 regulates the epithelial response to physical stress. These findings contribute to our understanding of the molecular mechanisms underlying hyperproliferation of the palmoplantar epidermis in both physiological and disease states, and how this 'stress' keratin is regulated
Clear Cell Renal Cell Carcinoma With a Poorly-Differentiated Component: A Novel Variant Causing Potential Diagnostic Difficulty
Background: Several variant histologic patterns of clear cell renal cell carcinoma (RCC) are well known, especially those with sarcomatoid and rhabdoid features. However, we have encountered rare cases in which a high-grade adenocarcinoma or urothelial carcinoma-like component would be difficult to appreciate as clear cell RCC. DesignWe retrieved 26 tumors with histologically typical clear cell RCC juxtaposed to a high-grade non-clear cell component.High grade non-clear cell component was defined as non-sarcomatoid, non-rhabdoid areas that would be difficult to assign as renal cell in origin if viewed in isolation. Tumors were studied with immunohistochemistry and fluorescence in situ hybridization (FISH) or sequencing.ResultsMedian percentage of poorly differentiated component: 50%(IQR20-70). All tumors showed abrupt transition from clear cell carcinoma to poorly-differentiated (non-sarcomatoid/non-rhabdoid) areas, which showed micropapillary (7/26; 27%), urothelial-like (10/26; 39%), and adenocarcinoma NOS features (9/26; 35%). 19 tumors had necrosis. Carbonic anhydrase IX (CA-IX) was uniformly positive in well-differentiated component (20/20); poorly differentiated component showed a median positivity of 82.5% (IQR 65-100). Poorly differentiated component was positive for CK7 (5/19; 26%), CK20 (3/12; 25%), AMACR (7/12; 58%), PAX8 (12/15; 80%), and showed intact FH (6/6; 100%). CDX2 was uniformly negative. Chromosome 3p loss or VHL mutation was present in 8/13 (62%), tested with either FISH (n = 9) or sequencing (n = 4). All tested cases were negative for TFE3 (0/11) and TFEB (0/9) rearrangements on FISH. 5/21 (24%) patients were alive with metastatic disease and 5/21 (24%) had died of disease on follow up. One metastasis was composed only of the poorly-differentiated component and was near-negative for CA-IX. Conclusion: Clear cell RCC with a poorly differentiated component resembling adenocarcinoma or urothelial carcinoma is a novel source of morphologic heterogeneity that has not been previously well characterized. Potential pitfalls include decreased or absent CA-IX staining the high-grade component and aberrant positivity for cytokeratin 7 or 20. With the increasing use of renal mass biopsy and biopsies of metastatic sites for targeted therapy, pathologists should be aware of this entity and consider the possibility of clear cell RCC even for morphologically unusual tumors.https://scholarlycommons.henryford.com/merf2019caserpt/1069/thumbnail.jp
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
X-ray emission from the Sombrero galaxy: discrete sources
We present a study of discrete X-ray sources in and around the
bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival
Chandra observations with a total exposure of ~200 ks. With a detection limit
of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30
kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler
et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS
observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray
binaries (LMXBs). We quantify the differential luminosity functions (LFs) for
both the detected GC and field LMXBs, whose power-low indices (~1.1 for the
GC-LF and ~1.6 for field-LF) are consistent with previous studies for
elliptical galaxies. With precise sky positions of the GCs without a detected
X-ray source, we further quantify, through a fluctuation analysis, the GC LF at
fainter luminosities down to 1E35 erg/s. The derived index rules out a
faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent
findings in several elliptical galaxies and the bulge of M31. On the other
hand, the 2-6 keV unresolved emission places a tight constraint on the field
LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101
sources in the halo of Sombrero. The presence of these sources cannot be
interpreted as galactic LMXBs whose spatial distribution empirically follows
the starlight. Their number is also higher than the expected number of cosmic
AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray
surveys. We suggest that either the cosmic X-ray background is unusually high
in the direction of Sombrero, or a distinct population of X-ray sources is
present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres
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