Vacuum structure of Toroidal Carbon Nanotubes

Low energy excitations in carbon nanotubes can be described by an effective field theory of two components spinor. It is pointed out that the chiral anomaly in 1+1 dimensions should be observed in a metallic toroidal carbon nanotube on a planar geometry with varying magnetic field. We propose an experimental setup for studying this quantum effect. We also analyze the vacuum structure of the metallic toroidal carbon nanotube including the Coulomb interactions and discuss some effects of external charges on the vacuum.Comment: 10 pages, 11 figure

The Final Fate of the Rolling Tachyon

We propose an alternative interpretation of the boundary state for the rolling tachyon, which may depict the time evolution of unstable D-branes in string theory. Splitting the string variable in the temporal direction into the classical part, which we may call "time" and the quantum one, we observe the time dependent behaviour of the boundary. Using the fermion representation of the rolling tachyon boundary state, we show that the boundary state correctly describes the time-dependent decay process of the unstable D-brane into a S-brane at the classical level.Comment: 9 pages, revte

Spin relaxation: From 2D to 1D

In inversion asymmetric semiconductors, spin-orbit interactions give rise to very effective relaxation mechanisms of the electron spin. Recent work, based on the dimensionally constrained D'yakonov Perel' mechanism, describes increasing electron-spin relaxation times for two-dimensional conducting layers with decreasing channel width. The slow-down of the spin relaxation can be understood as a precursor of the one-dimensional limit

COVID-19 and stem cell transplantation; results from an EBMT and GETH multicenter prospective survey

Altres ajuts: British Society for Blood and Marrow Transplantation and Cellular Therapy (BSBMTCT); UK NIHR Imperial College Biomedical Research Centre.This study reports on 382 COVID-19 patients having undergone allogeneic (n = 236) or autologous (n = 146) hematopoietic cell transplantation (HCT) reported to the European Society for Blood and Marrow Transplantation (EBMT) or to the Spanish Group of Hematopoietic Stem Cell Transplantation (GETH). The median age was 54.1 years (1.0-80.3) for allogeneic, and 60.6 years (7.7-81.6) for autologous HCT patients. The median time from HCT to COVID-19 was 15.8 months (0.2-292.7) in allogeneic and 24.6 months (−0.9 to 350.3) in autologous recipients. 83.5% developed lower respiratory tract disease and 22.5% were admitted to an ICU. Overall survival at 6 weeks from diagnosis was 77.9% and 72.1% in allogeneic and autologous recipients, respectively. Children had a survival of 93.4%. In multivariate analysis, older age (p = 0.02), need for ICU (p < 0.0001) and moderate/high immunodeficiency index (p = 0.04) increased the risk while better performance status (p = 0.001) decreased the risk for mortality. Other factors such as underlying diagnosis, time from HCT, GVHD, or ongoing immunosuppression did not significantly impact overall survival. We conclude that HCT patients are at high risk of developing LRTD, require admission to ICU, and have increased mortality in COVID-19

First Sagittarius A* event horizon telescope results. II. EHT and multiwavelength observations, data processing, and calibration

Instrumentatio

Food Safety Knowledge and Behaviors of Women, Infant, and Children (WIC) Program Participants in the United States

Although the incidence of foodborne illnesses has declined, thousands of cases are still reported in the United States. In conjunction with industry efforts to reduce foodborne pathogens, consumers play an important role in decreasing foodborne illnesses. To assess food safety knowledge and food handling behaviors of low-income, high-risk populations, a study was conducted with participants of the Special Supplemental Food Program for Women, Infants, and Children (WIC). A survey was conducted with 1,598 clients from 87 WIC agencies nationwide. Descriptive statistics, chi-square analyses, t tests, and analyses of variance were calculated. A majority of respondents received food safety information from WIC (78.7%), family (63.1%), and television (60.7%). Most respondents recognized the necessity for washing and sanitizing cutting boards and utensils (94.3%), but only 66.1% knew the correct ways to sanitize. Using a thermometer to ensure doneness of meat was least recognized (23.7%) and used by even fewer respondents (7.7%). The majority (77.4%) used color of meat and/or juices when checking the doneness of ground beef items. Over half of the respondents (58.4%) used acceptable thawing methods, but many thawed frozen meats on the counter (21.0%) or in a sink filled with water (20.6%). There were significant differences in thawing methods, overall knowledge scores, and overall behavior scores among different racial and ethnic groups. White respondents had higher knowledge scores than did Hispanics, and blacks had lower behavior scores than did individuals in the other racial and ethnic groups. Results of the study suggested the need for food safety education for low-income consumers and different messages to be delivered to specific demographic groups