143 research outputs found
On the Momentum Dependence of the Flavor Structure of the Nucleon Sea
Difference between the and sea quark distributions in the
proton was first observed in the violation of the Gottfried sum rule in
deep-inelastic scattering (DIS) experiments. The parton momentum fraction
dependence of this difference has been measured over the region from Drell-Yan and semi-inclusive DIS experiments. The Drell-Yan data
suggested a possible sign-change for near ,
which has not yet been explained by existing theoretical models. We present an
independent evidence for the sign-change at
from an analysis of the DIS data. We further discuss the -dependence of
in the context of meson cloud model and the lattice QCD
formulation.Comment: 5 pages, 5 figures, final versio
Connected-Sea Partons
According to the path-integral formalism of the hadronic tensor, the nucleon
sea contains two distinct components called connected sea (CS) and disconnected
sea (DS). We discuss how the CS and DS are accessed in the lattice QCD
calculation of the moments of the parton distributions. We show that the CS and
DS components for can be extracted by using recent data
on the strangeness parton distribution, the CT10 global fit, and the lattice
result of the ratio of the strange to moments in the disconnected
insertion. The extracted CS and DS for have distinct
Bjorken dependence in qualitative agreement with expectation. The analysis
also shows that the momentum fraction of the is about
equally divided between CS and DS at . Implications on
future global analysis for parton distributions are presented.Comment: Revised version to be published in Phys. Rev. Let
Medial reward and lateral non-reward orbitofrontal cortex circuits change in opposite directions in depression
The first brain-wide voxel-level resting state functional-connectivity neuroimaging analysis of depression is reported, with 421 patients with major depressive disorder and 488 controls. Resting state functional connectivity between different voxels reflects correlations of activity between those voxels and is a fundamental tool in helping to understand the brain regions with altered connectivity and function in depression.
One major circuit with altered functional connectivity involved the medial orbitofrontal cortex BA 13, which is implicated in reward, and which had reduced functional connectivity in depression with memory systems in the parahippocampal gyrus and medial temporal lobe, especially involving the perirhinal cortex BA 36 and entorhinal cortex BA 28. The Hamilton Depression Rating Scale scores were correlated with weakened functional connectivity of the medial orbitofrontal cortex BA 13. Thus in depression there is decreased reward-related and memory system functional connectivity, and this is related to the depressed symptoms. The lateral orbitofrontal cortex BA 47/12, involved in non-reward and punishing events, did not have this reduced functional connectivity with memory systems.
Second, the lateral orbitofrontal cortex BA 47/12 had increased functional connectivity with the precuneus, the angular gyrus, and the temporal visual cortex BA 21. This enhanced functional connectivity of the non-reward/punishment system (BA 47/12) with the precuneus (involved in the sense of self and agency), and the angular gyrus (involved in language) is thus related to the explicit affectively negative sense of the self, and of self-esteem, in depression. A comparison of the functional connectivity in 185 depressed patients not receiving medication and 182 patients receiving medication showed that the functional connectivity of the lateral orbitofrontal cortex BA 47/12 with these three brain areas was lower in the medicated than the unmedicated patients. This is consistent with the hypothesis that the increased functional connectivity of the lateral orbitofrontal cortex BA 47/12 is related to depression.
Relating the changes in cortical connectivity to our understanding of the functions of different parts of the orbitofrontal cortex in emotion helps to provide new insight into the brain changes related to depression, which are considered in the Discussion
Lack of association of genetic variants for diabetic retinopathy in Taiwanese patients with diabetic nephropathy
[[abstract]]Objective Diabetic nephropathy (DN) and diabetic
retinopathy (DR) comprise major microvascular
complications of diabetes that occur with a high
concordance rate in patients and are considered to
potentially share pathogeneses. In this case-control
study, we sought to investigate whether DR-related single
nucleotide polymorphisms (SNPs) exert pleiotropic effects
on renal function outcomes among patients with diabetes.
Research design and methods A total of 33 DR-related
SNPs were identified by replicating published SNPs and
via a genome-wide association study. Furthermore, we
assessed the cumulative effects by creating a weighted
genetic risk score and evaluated the discriminatory and
prediction ability of these genetic variants using DN cases
according to estimated glomerular filtration rate (eGFR)
status along with a cohort with early renal functional
decline (ERFD).
Results Multivariate logistic regression models revealed
that the DR-related SNPs afforded no individual or
cumulative genetic effect on the nephropathy risk, eGFR
status or ERFD outcome among patients with type two
diabetes in Taiwan.
Conclusion Our findings indicate that larger studies would
be necessary to clearly ascertain the effects of individual
genetic variants and further investigation is also required
to identify other genetic pathways underlying DN.[[notice]]補æ£å®Œ
Women with endometriosis have higher comorbidities: Analysis of domestic data in Taiwan
AbstractEndometriosis, defined by the presence of viable extrauterine endometrial glands and stroma, can grow or bleed cyclically, and possesses characteristics including a destructive, invasive, and metastatic nature. Since endometriosis may result in pelvic inflammation, adhesion, chronic pain, and infertility, and can progress to biologically malignant tumors, it is a long-term major health issue in women of reproductive age. In this review, we analyze the Taiwan domestic research addressing associations between endometriosis and other diseases. Concerning malignant tumors, we identified four studies on the links between endometriosis and ovarian cancer, one on breast cancer, two on endometrial cancer, one on colorectal cancer, and one on other malignancies, as well as one on associations between endometriosis and irritable bowel syndrome, one on links with migraine headache, three on links with pelvic inflammatory diseases, four on links with infertility, four on links with obesity, four on links with chronic liver disease, four on links with rheumatoid arthritis, four on links with chronic renal disease, five on links with diabetes mellitus, and five on links with cardiovascular diseases (hypertension, hyperlipidemia, etc.). The data available to date support that women with endometriosis might be at risk of some chronic illnesses and certain malignancies, although we consider the evidence for some comorbidities to be of low quality, for example, the association between colon cancer and adenomyosis/endometriosis. We still believe that the risk of comorbidity might be higher in women with endometriosis than that we supposed before. More research is needed to determine whether women with endometriosis are really at risk of these comorbidities
Potential of Core-Collapse Supernova Neutrino Detection at JUNO
JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve
Detection of the Diffuse Supernova Neutrino Background with JUNO
As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO
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