Statistical effect in the parton distribution functions of the nucleon

A new and simple statistical approach is performed to calculate the parton distribution functions (PDFs) of the nucleon in terms of light-front kinematic variables. We do not put in any extra arbitrary parameter or corrected term by hand, which guarantees the stringency of our approach. Analytic expressions of the $x$-dependent PDFs are obtained in the whole $x$ region [0,1], and some features, especially the low-$x$ rise, are more agreeable with experimental data than those in some previous instant-form statistical models in the infinite-momentum frame (IMF). Discussions on heavy-flavored PDFs are also presented.Comment: 16 latex pages, 10 figures, to appear in PL

The analysis on the single particle model of CDW

Gruner put forward a single particle model of charge-density wave, which is a typical nonlinear differential equation, and also a mathematical model of pendulum. This Letter analyzes the solution of equation by the rotated vector fields theory, providing the relation between the applied field E and the periodic solution, and the conclusion that the critical value of E for the periodic solution is fixed in the over-damped situation. With these conclusions, it derives the formulae of nonlinear conductivity, narrow-band noise, which are consistent with the empirical ones given by Fleming.Comment: This is a version with a physics focus, the part with a mathematical focus is submitted at arXiv:0807.328

Synthesizing attractors of Hindmarsh-Rose neuronal systems

In this paper a periodic parameter switching scheme is applied to the Hindmarsh-Rose neuronal system to synthesize certain attractors. Results show numerically, via computer graphic simulations, that the obtained synthesized attractor belongs to the class of all admissible attractors for the Hindmarsh-Rose neuronal system and matches the averaged attractor obtained with the control parameter replaced with the averaged switched parameter values. This feature allows us to imagine that living beings are able to maintain vital behavior while the control parameter switches so that their dynamical behavior is suitable for the given environment.Comment: published in Nonlinear Dynamic

Systematic decay studies of even-even 132−138132-138^Nd, 144−158144-158^Gd, 176−196176-196^Hg and 192−198192-198^Pb isotopes

The alpha and cluster decay properties of the $132-138$^Nd, $144-158$^Gd, $176-196$^Hg and $192-198$^Pb even-even isotopes in the two mass regions A = 130-158 and A = 180-198 are analysed using the Coulomb and Proximity Potential Model. On examining the clusters at corresponding points in the cold valleys (points with same A_2) of the various isotopes of a particular nucleus we find that at certain mass numbers of the parent nuclei, the clusters emitted are getting shifted to the next lower atomic number. It is interesting to see that the change in clusters appears at those isotopes where a change in shape is occurring correspondingly. Such a change of clusters with shape change is studied for the first time in cluster decay. The alpha decay half lives of these nuclei are computed and these are compared with the available experimental alpha decay data. It is seen that the two are in good agreement. On making a comparison of the alpha half lives of the normal deformed and super deformed nuclei, it can be seen that the normal deformed $132$^Nd, $176-188$^Hg and $192$^Pb nuclei are found to be better alpha emitters than the super deformed (in excited state) $134,136$^Nd, $190-196$^Hg and $194$^Pb nuclei. The cluster decay studies reveal that as the atomic number of the parent nuclei increases the N \neq Z cluster emissions become equally or more probable than the N=Z emissions. On the whole the alpha and cluster emissions are more probable from the parents in the heavier mass region (A=180-198) than from the parents in the lighter mass region (A= 130-158). The effect of quadrupole ({\beta}_2) and hexadecapole ({\beta}_4) deformations of parent and fragments on half life times are also studied.Comment: 42 pages,19 figure

One year follow-up of physical performance and quality of life in patients surviving COVID-19: a prospective cohort study

INTRODUCTION: The coronavirus disease (COVID-19) continues to affect many countries globally, with the long-term impact of the disease now being recognized. According to the latest research, some of the affected individuals continue to experience functional limitations, reduced physical performance and impaired health-related quality of life (HRQoL) even after eight months. This prospective cohort study aimed to describe the longer-term recovery of physical performance and HRQoL in COVID-19 survivors over one year. METHOD: A cohort (n = 43; 32-84 years old) hospitalized with COVID-19 between March and June 2020 was followed over one year and assessed at three time points: hospital discharge, 3 months and 12 months post-admission. Participants experienced mild (10/43) to critical (6/43) pneumonia and stayed in the hospital for a median of 10 days (IQR 9). Participants were assessed for physical performance (six-minute walk test), HRQoL (EQ-5D-5L), COVID-19 related limitations in functionality (PCFS), hospital-related anxiety and depression (HADS-A/-D), lung function (FEV1, FVC) and dyspnea during activity (mMRC). All assessments were conducted by physiotherapists trained in cardio-respiratory rehabilitation. RESULTS: After discharge, 8/34 showed reduced physical performance, 9/42 had lower HRQoL and 14/32 had COVID-19 induced limitations in functionality on the PCFS scale. Physical performance did not change significantly between discharge and 12-month follow-up, but 15/34 participants showed clinically relevant improvements in walking distance (>30 m). However, 16/34 had a decreased walking distance >30 m when comparing 3-month to 12-month follow-up. At 12 months, 12/41 of participants still perceived COVID-19 related limitations in daily life on the PCFS scale. For HRQoL, 12/41 participants still perceived moderate-to-severe symptoms of pain and discomfort and 13/41 slight-to-severe symptoms of anxiety and depression. CONCLUSION: This cohort of adult patients hospitalized for mild to severe COVID-19 in Switzerland was generally mildly affected but still reported some limitations after one year. These results offer preliminary indications for ongoing support after hospitalization and point towards the need for specific, individualized follow-up to support their recovery. ClinicalTrials.gov (NCT04375709

Biological structure and function emerge from scaling unsupervised learning to 250 million protein sequences

In the field of artificial intelligence, a combination of scale in data and model capacity enabled by unsupervised learning has led to major advances in representation learning and statistical generation. In the life sciences, the anticipated growth of sequencing promises unprecedented data on natural sequence diversity. Protein language modeling at the scale of evolution is a logical step toward predictive and generative artificial intelligence for biology. To this end, we use unsupervised learning to train a deep contextual language model on 86 billion amino acids across 250 million protein sequences spanning evolutionary diversity. The resulting model contains information about biological properties in its representations. The representations are learned from sequence data alone. The learned representation space has a multiscale organization reflecting structure from the level of biochemical properties of amino acids to remote homology of proteins. Information about secondary and tertiary structure is encoded in the representations and can be identified by linear projections. Representation learning produces features that generalize across a range of applications, enabling state-of-the-art supervised prediction of mutational effect and secondary structure and improving state-of-the-art features for long-range contact prediction

Physicians Infrequently Adhere to Hepatitis Vaccination Guidelines for Chronic Liver Disease

Background and Goals:Hepatitis A (HAV) and hepatitis B (HBV) vaccination in patients with chronic liver disease is an accepted standard of care. We determined HAV and HBV vaccination rates in a tertiary care referral hepatology clinic and the impact of electronic health record (EHR)-based reminders on adherence to vaccination guidelines.Methods:We reviewed the records of 705 patients with chronic liver disease referred to our liver clinic in 2008 with at least two follow-up visits during the subsequent year. Demographics, referral source, etiology, and hepatitis serology were recorded. We determined whether eligible patients were offered vaccination and whether patients received vaccination. Barriers to vaccination were determined by a follow-up telephone interview.Results:HAV and HBV serologic testing prior to referral and at the liver clinic were performed in 14.5% and 17.7%; and 76.7% and 74% patients, respectively. Hepatologists recommended vaccination for HAV in 63% and for HBV in 59.7% of eligible patients. Patient demographics or disease etiology did not influence recommendation rates. Significant variability was observed in vaccination recommendation amongst individual providers (30-98.6%), which did not correlate with the number of patients seen by each physician. Vaccination recommendation rates were not different for Medicare patients with hepatitis C infection for whom a vaccination reminder was automatically generated by the EHR. Most patients who failed to get vaccination after recommendation offered no specific reason for noncompliance; insurance was a barrier in a minority.Conclusions:Hepatitis vaccination rates were suboptimal even in an academic, sub-speciality setting, with wide-variability in provider adherence to vaccination guidelines. © 2013 Thudi et al