234 research outputs found
Expectations for LHC from Naturalness: Modified vs. SM Higgs Sector
Common lore has it that naturalness of electroweak breaking in the SM
requires new physics (NP) at Lambda < 2-3 TeV, hopefully within the reach of
LHC. Moreover the Higgs should be light (m_h < 219 GeV) to pass electroweak
precision tests (EWPT). However one should be prepared for "unexpected"
(although admittedly unpleasant) results at LHC, i.e. no NP and/or a heavy
Higgs. We revisit recent attempts to accommodate this by modifying the SM Higgs
sector (using 2-Higgs-doublet models). We find that these models do not improve
the naturalness of the SM, and so they do not change the expectations of
observing NP at LHC. We also stress that a heavy SM Higgs would not be evidence
in favour of a modified Higgs sector, provided certain higher order operators
influence EWPT. On the other hand, we show that NP can escape LHC detection
without a naturalness price, and with the pure SM as the effective theory valid
at LHC energies, simply if the cut-off for top loops is slightly lower than for
Higgs loops.Comment: 37 pages, LaTeX, 13 figure
Low Background Micromegas in CAST
Solar axions could be converted into x-rays inside the strong magnetic field
of an axion helioscope, triggering the detection of this elusive particle. Low
background x-ray detectors are an essential component for the sensitivity of
these searches. We report on the latest developments of the Micromegas
detectors for the CERN Axion Solar Telescope (CAST), including technological
pathfinder activities for the future International Axion Observatory (IAXO).
The use of low background techniques and the application of discrimination
algorithms based on the high granularity of the readout have led to background
levels below 10 counts/keV/cm/s, more than a factor 100 lower than
the first generation of Micromegas detectors. The best levels achieved at the
Canfranc Underground Laboratory (LSC) are as low as 10
counts/keV/cm/s, showing good prospects for the application of this
technology in IAXO. The current background model, based on underground and
surface measurements, is presented, as well as the strategies to further reduce
the background level. Finally, we will describe the R&D paths to achieve
sub-keV energy thresholds, which could broaden the physics case of axion
helioscopes.Comment: 6 pages, 3 figures, Large TPC Conference 2014, Pari
"I'm not just a heart, I'm a whole person here": a qualitative study to improve sexual outcomes in women with myocardial infarction
Background: Little is known about recovery of female sexual function following an acute myocardial infarction (MI). Interventions to improve sexual outcomes in women are limited. Methods and Results: Semistructured, qualitative telephone interviews were conducted with 17 partnered women (aged 43 to 75 years) purposively selected from the Translational Research Investigating Underlying Disparities in Acute Myocardial Infarction Patients’ Health Status Registry to deepen knowledge of recovery of female sexual function following an acute myocardial infarction (MI) and to improve sexual outcomes in women. Sixteen women had a monogamous relationship with a male spouse; 1 had a long‐term female partner. Most women resumed sexual activity within 4 weeks of their MI. Sexual problems and concerns were prevalent, including patient and/or partner fear of “causing another heart attack.” Few women received counseling about sexual concerns or the safety of returning to sex. Most women who discussed sex with a physician initiated the discussion themselves. Inquiry about strategies to improve sexual outcomes elicited key themes: need for privacy, patient‐centeredness, and information about the timing and safe resumption of sexual activity. In addition, respondents felt that counseling should be initiated by the treating cardiologist, who “knows whether your heart is safe,” and then reinforced by the care team throughout the rehabilitation period. Conclusions: Partnered women commonly resume sexual activity soon after an MI with fear but without directed counseling from their physicians. Proactive attention to women's concerns related to sexual function and the safety of sexual activity following an MI could improve post‐MI outcomes for women and their partners.Emily M. Abramsohn, Carole Decker, Brian Garavalia, Linda Garavalia, Kensey Gosch, Harlan M. Krumholz, John A. Spertus and Stacy Tessler Linda
Search for the glueball candidates f0(1500) and fJ(1710) in gamma gamma collisions
Data taken with the ALEPH detector at LEP1 have been used to search for gamma
gamma production of the glueball candidates f0(1500) and fJ(1710) via their
decay to pi+pi-. No signal is observed and upper limits to the product of gamma
gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have
been measured to be Gamma_(gamma gamma -> f0(1500)). BR(f0(1500)->pi+pi-) <
0.31 keV and Gamma_(gamma gamma -> fJ(1710)). BR(fJ(1710)->pi+pi-) < 0.55 keV
at 95% confidence level.Comment: 10 pages, 3 figure
Resveratrol Targeting of Carcinogen-Induced Brain Endothelial Cell Inflammation Biomarkers MMP-9 and COX-2 is Sirt1-Independent
The occurrence of a functional relationship between the release of metalloproteinases (MMPs) and the expression of cyclooxygenase (COX)-2, two inducible pro-inflammatory biomarkers with important pro-angiogenic effects, has recently been inferred. While brain endothelial cells play an essential role as structural and functional components of the blood-brain barrier (BBB), increased BBB breakdown is thought to be linked to neuroinflammation. Chemopreventive mechanisms targeting both MMPs and COX-2 however remain poorly investigated. In this study, we evaluated the pharmacological targeting of Sirt1 by the diet-derived and antiinflammatory polyphenol resveratrol. Total RNA, cell lysates, and conditioned culture media from human brain microvascular endothelial cells (HBMEC) were analyzed using qRT-PCR, immunoblotting, and zymography respectively. Tissue scan microarray analysis of grade I–IV brain tumours cDNA revealed increased gene expression of Sirt-1 from grade I–III but surprisingly not in grade IV brain tumours. HBMEC were treated with a combination of resveratrol and phorbol 12-myristate 13-acetate (PMA), a carcinogen known to increase MMP-9 and COX-2 through NF-κB. We found that resveratrol efficiently reversed the PMA-induced MMP-9 secretion and COX-2 expression. Gene silencing of Sirt1, a critical modulator of angiogenesis and putative target of resveratrol, did not lead to significant reversal of MMP-9 and COX-2 inhibition. Decreased resveratrol inhibitory potential of carcinogen-induced IκB phosphorylation in siSirt1-transfected HBMEC was however observed. Our results suggest that resveratrol may prevent BBB disruption during neuroinflammation by inhibiting MMP-9 and COX-2 and act as a pharmacological NF-κB signal transduction inhibitor independent of Sirt1
Ex vivo fucosylation improves human cord blood engraftment in NOD-SCID IL-2Rγ null mice
Delayed engraftment remains a major hurdle after cord blood (CB) transplantation. It may be due, at least in part, to low fucosylation of cell surface molecules important for homing to the bone marrow microenvironment. Because fucosylation of specific cell surface ligands is required before effective interaction with selectins expressed by the bone marrow microvasculature can occur, a simple 30-minute ex vivo incubation of CB hematopoietic progenitor cells with fucosyltransferase-VI and its substrate (GDP-fucose) was performed to increase levels of fucosylation. The physiologic impact of CB hematopoietic progenitor cell hypofucosylation was investigated in vivo in NOD-SCID interleukin (IL)-2Rγ null (NSG) mice. By isolating fucosylated and nonfucosylated CD34 + cells from CB, we showed that only fucosylated CD34 + cells are responsible for engraftment in NSG mice. In addition, because the proportion of CD34 + cells that are fucosylated in CB is significantly less than in bone marrow and peripheral blood, we hypothesize that these combined observations might explain, at least in part, the delayed engraftment observed after CB transplantation. Because engraftment appears to be correlated with the fucosylation of CD34 + cells, we hypothesized that increasing the proportion of CD34 + cells that are fucosylated would improve CB engraftment. Ex vivo treatment with fucosyltransferase-VI significantly increases the levels of CD34 + fucosylation and, as hypothesized, this was associated with improved engraftment. Ex vivo fucosylation did not alter the biodistribution of engrafting cells or pattern of long-term, multilineage, multi-tissue engraftment. We propose that ex vivo fucosylation will similarly improve the rate and magnitude of engraftment for CB transplant recipients in a clinical setting
HighP–TNano-Mechanics of Polycrystalline Nickel
We have conducted highP–Tsynchrotron X-ray and time-of-flight neutron diffraction experiments as well as indentation measurements to study equation of state, constitutive properties, and hardness of nanocrystalline and bulk nickel. Our lattice volume–pressure data present a clear evidence of elastic softening in nanocrystalline Ni as compared with the bulk nickel. We show that the enhanced overall compressibility of nanocrystalline Ni is a consequence of the higher compressibility of the surface shell of Ni nanocrystals, which supports the results of molecular dynamics simulation and a generalized model of a nanocrystal with expanded surface layer. The analytical methods we developed based on the peak-profile of diffraction data allow us to identify “micro/local” yield due to high stress concentration at the grain-to-grain contacts and “macro/bulk” yield due to deviatoric stress over the entire sample. The graphic approach of our strain/stress analyses can also reveal the corresponding yield strength, grain crushing/growth, work hardening/softening, and thermal relaxation under highP–Tconditions, as well as the intrinsic residual/surface strains in the polycrystalline bulks. From micro-indentation measurements, we found that a low-temperature annealing (T < 0.4 Tm) hardens nanocrystalline Ni, leading to an inverse Hall–Petch relationship. We explain this abnormal Hall–Petch effect in terms of impurity segregation to the grain boundaries of the nanocrystalline Ni
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