3,394 research outputs found
BPS Wilson loops and Bremsstrahlung function in ABJ(M): a two loop analysis
We study a family of circular BPS Wilson loops in N=6 super
Chern-Simons-matter theories, generalizing the usual 1/2-BPS circle. The scalar
and fermionic couplings depend on two deformation parameters and these
operators can be considered as the ABJ(M) counterpart of the DGRT latitudes
defined in N=4 SYM. We perform a complete two-loop analysis of their vacuum
expectation value, discuss the framing dependence and propose a general
relation with cohomologically equivalent bosonic operators. We make an all-loop
proposal for computing the Bremsstrahlung function associated to the 1/2-BPS
cusp in terms of these generalized Wilson loops. When applied to our two-loop
result it reproduces the known expression. Finally, we comment on the
generalization of this proposal to the bosonic 1/6-BPS case.Comment: 46 pages, 6 figures; references adde
A matrix model for the latitude Wilson loop in ABJM theory
In ABJ(M) theory, we propose a matrix model for the exact evaluation of BPS
Wilson loops on a latitude circular contour, so providing a new weak-strong
interpolation tool. Intriguingly, the matrix model turns out to be a particular
case of that computing torus knot invariants in Chern-Simons
theory. At weak coupling we check our proposal against a three-loop
computation, performed for generic framing, winding number and representation.
The matrix model is amenable of a Fermi gas formulation, which we use to
systematically compute the strong coupling and genus expansions. For the
fermionic Wilson loop the leading planar behavior agrees with a previous string
theory prediction. For the bosonic operator our result provides a clue for
finding the corresponding string dual configuration. Our matrix model is
consistent with recent proposals for computing Bremsstrahlung functions exactly
in terms of latitude Wilson loops. As a by-product, we extend the conjecture
for the exact Bremsstrahlung function to generic
representations and test it with a four-loop perturbative computation. Finally,
we propose an exact prediction for at unequal gauge group ranks.Comment: 73 pages; v2: several improvements, JHEP published versio
The quantum 1/2 BPS Wilson loop in Chern-Simons-matter theories
In three dimensional Chern-Simons-matter theories two
independent fermionic Wilson loop operators can be defined, which preserve half
of the supersymmetry charges and are cohomologically equivalent at classical
level. We compute their three-loop expectation value in a convenient color
sector and prove that the degeneracy is uplifted by quantum corrections. We
expand the matrix model prediction in the same regime and by comparison we
conclude that the quantum 1/2 BPS Wilson loop is the average of the two
operators. We provide an all-loop argument to support this claim at any order.
As a by-product, we identify the localization result at three loops as a
correction to the framing factor induced by matter interactions. Finally, we
comment on the quantum properties of the non-1/2 BPS Wilson loop operator
defined as the difference of the two fermionic ones.Comment: 22 pages + appendixes, 4 figures, 1 Tabl
Towards the exact Bremsstrahlung function of ABJM theory
We present the three-loop calculation of the Bremsstrahlung function
associated to the 1/2-BPS cusp in ABJM theory, including color subleading
corrections. Using the BPS condition we reduce the computation to that of a
cusp with vanishing angle. We work within the framework of heavy quark
effective theory (HQET) that further simplifies the analytic evaluation of the
relevant cusp anomalous dimension in the near-BPS limit. The result passes
nontrivial tests, such as exponentiation, and is in agreement with the
conjecture made in [1] for the exact expression of the Bremsstrahlung function,
based on the relation with fermionic latitude Wilson loops.Comment: 46 pages, 15 figure
Gene-specific methylation profiles in BRCA-mutation positive and BRCA-mutation negative male breast cancers
Male breast cancer (MBC) is a rare disease. Due to its rarity, MBC research and clinical approach are mostly based upon data derived from female breast cancer (FBC). Increasing evidence indicate that on molecular level MBC may be an heterogeneous disease different from FBC. In order to investigate whether epigenetic signatures could define molecular subgroups of MBCs, we performed promoter methylation analysis of genes involved in signal transduction and hormone signalling in BRCA1/2 mutation-positive and -negative MBCs. We examined 69 MBCs, paired blood samples, and 15 normal tissues for promoter methylation of hTERT, ESR1, RASSF1, AR, MYC and WNT1 genes. MBCs showed higher gene promoter methylation levels compared to paired blood and normal breast samples. Significantly higher RASSF1 methylation levels were observed in association with BRCA1/2 mutations, HER2 expression and high tumor grade. Significantly higher AR methylation levels were observed in BRCA1/2 wild-type cases and higher WNT1 methylation levels in PR negative cases. Overall, our results indicate that alterations in gene methylation profiles are common in MBC and that methylation pattern of tumor-associated genes may allow for the identification of MBC molecular subgroups, that could have implications in clinical management of MBC patients
Large-eddy simulation of the aerodynamic and aeroacoustic performance of a ventilation fan
There are controversial requirements involved in developing numerical methodologies in order to compute the flow in industrial fans. The full resolution of turbulence spectrum in such high-Reynolds number flow configurations entails unreasonably expensive computational costs. The authors applied the study to a large unidirectional axial flow fan unit for tunnel ventilation to operate in the forward direction under ambient conditions. This delivered cooling air to the tunnel under routine operation, or hot gases at 400∘C under emergency conditions in the event of a tunnel fire. The simulations were carried out using the open source code OpenFOAM, within which they implemented a very large eddy simulation (VLES) based on one-equation SGS model to solve a transport equation for the modelled (subgrid) turbulent kinetic energy. This subgrid turbulence model improvement is a remedial strategy in VLES of high-Reynolds number industrial flows which are able to tackle the turbulence spectrum's well-known insufficient resolution. The VLES of the industrial fan permits detecting the unsteady topology of the rotor flow. This paper explores the evolution of secondary flow phenomena and speculates on its influence on the actual load capability when operating at peak-pressure condition. Predicted noise emissions, in terms of sound pressure level spectra, are also compared with experimental results and found to agree within the uncertainty of the measurements
Sars-cov-2 envelope and membrane proteins: structural differences linked to virus characteristics?
The Coronavirus Disease 2019 (COVID-19) is a new viral infection caused by the severe acute respiratory coronavirus 2 (SARS-CoV-2). Genomic analyses have revealed that SARS-CoV-2 is related to Pangolin and Bat coronaviruses. In this report, a structural comparison between the Sars-CoV-2 Envelope and Membrane proteins from different human isolates with homologous proteins from closely related viruses is described. The analyses here reported show the high structural similarity of Envelope and Membrane proteins to the counterparts from Pangolin and Bat coronavirus isolates. However, the comparisons have also highlighted structural differences specific of Sars-CoV-2 proteins which may be correlated to the cross-species transmission and/or to the properties of the virus. Structural modelling has been applied to map the variant sites onto the predicted three-dimensional structure of the Envelope and Membrane proteins
Smoking and FGFR2 rs2981582 variant independently modulate male breast cancer survival: A population-based study in Tuscany, Italy
Aim: Male breast cancer (MBC) is a rare disease and recommendations for its clinical management are often extrapolated from those for female breast cancer, even if breast cancer (BC) has different characteristics in the two sexes. The purpose of this study was to assess the influence of several individual characteristics including clinico-pathological, lifestyle and genetic factors on overall survival (OS) of a relatively large and well characterized population-based series of 166 MBCs enrolled in Tuscany. Methods: We genotyped MBC cases at BRCA1/2 genes and at 9 candidate BC susceptibility SNPs. Kaplan-Meier method and multivariate Cox regression, adjusted for several individual characteristics were used. To reduce a possible selection bias related to the interval between diagnosis and enrolment of MBC cases into the study, we used the date of blood donation as the date of the start of observation for survival analysis. Results: Only smoking habits had a significant effect on OS at 10 years (for current smokers, HR: 3.34; 95% CI 1.45–7.68; p = 0.004), while lymph node status fell short of reaching statistical significance (for pN positive, HR: 2.07; 95% CI 0.93–4.55; p = 0.07). In the same multivariate analysis we found a significantly higher OS in cases with FGFR2 rs2981582 variant in the dominant transmission model (HR: 0.29; 95% CI: 0.13–0.62; p = 0.028). A sensitivity analysis with left truncation showed similar results. Conclusions: Our results may contribute to shed light on factors influencing MBC survival suggesting an important role for cigarette smoking and FGFR2 rs2981582 variant, and provide clues for better patient management
Sac enlargement due to seroma after endovascular abdominal aortic aneurysm repair with the Endologix PowerLink device
A patient who had undergone endovascular repair of an abdominal aortic aneurysm with the Endologix PowerLink bifurcated system presented with delayed aortic aneurysm enlargement due to assumed endotension. He was treated with aortic sac evacuation and wrapping of the endograft. This is the first report of endotension and aneurysm sac enlargement after implantation of the PowerLink endograft
A predictive index of intra-dialysis IDH. A statistical clinical data mining approach.
Intra-Dialysis Hypotension (IDH) is one of the main hemodialysis related complications, occurring in 25-30% of the sessions. The factors involved in the onset of hypotension in patients undergoing dialysis are due both to clinical conditions (e.g. presence of vascular or cardiac diseases, neuropathology, anemia) and treatment settings such as temperature of the dialysate, sodium concentration, buffer composition,
ultrafiltration rate, etc. The patient’s peculiar reaction to the treatment implies difficulties in preventing IDH episodes. This work explores the possibility to use a multivariate analysis of clinical data to quantify the risk to develop IDH at the beginning
of each session. The study is framed in the DialysIS project (Dialysis therapy between Italy and Switzerland) funded by INTERREG – Italy – Switzerland and Co-funded by European Union. Data referring to a total of 516 sessions performed on 70 adult patients undergoing dialysis treatment (50 patients enrolled at A. Manzoni Hospital Lecco, Italy and 20 patients at Regional Hospital of Lugano, Switzerland) were collected. Clinical prescriptions, hydration status, dialysis machine data and hematochemical data were recorded and stored in a unique
flexible structured MySQL® database. A statistical analysis was performed to find the potential risk factor related to IDH onset. IDH episodes were automatically detected during the monitored sessions, according to the literature criteria. Patients suffering from IDH in 2 or more sessions were classified as Hypotension Prone (HP), the others as Hypotension Resistant (HR). Initial values of potassium concentration [K+], systolic (SBP) and diastolic (DBP) blood pressure, and weight gain (ΔW) from the end of the previous treatment result to be statistically
different between the HP and HR groups.
A new index, J, was defined as a weighted patient-specific combination of these parameters and calculated for each session of each patient. The weight of the index coefficients can be dynamically adjourned based on the longitudinal analysis of [K+], SBP, DBP, and ΔW. The results reported in this paper were calculated based on a longitudinal analysis of a minimum of three sessions for each patient. The accuracy of the J index in predicting IDH events has been evaluated and quantified in terms of percentage number of predicted IDH events, with respect to the total number of IDHs.
Values of J index higher than 1 point out the risk of IDH onset. J allows the prediction of 100% of IDH episodes using 5 sessions, the 90% using 3 sessions. More specifically, at Lecco Hospital 43 IDH events were detected by the automatic system of which 100% and 95% were respectively predicted by the new index calculated using 5 or 3 sessions. Similarly, at Lugano Hospital 58 IDH were detected by the automatic system of which 100% and 87,5% were predicted using 5 or 3 sessions respectively. A longer longitudinal dataset will allow a higher matching of J to actual IDH episodes.
In conclusion, the evaluation of this new index at the beginning of the dialysis session prior to connecting the patient to the machine can provide the clinician with useful information about the risk for the patient to develop cardiovascular instabilities (IDH) during the treatment and can advise the physician about the need to modify the prescription
- …