Survey of vector-like fermion extensions of the Standard Model and their phenomenological implications

With the renewed interest in vector-like fermion extensions of the Standard Model, we present here a study of multiple vector-like theories and their phenomenological implications. Our focus is mostly on minimal flavor conserving theories that couple the vector-like fermions to the SM gauge fields and mix only weakly with SM fermions so as to avoid flavor problems. We present calculations for precision electroweak and vector-like state decays, which are needed to investigate compatibility with currently known data. We investigate the impact of vector-like fermions on Higgs boson production and decay, including loop contributions, in a wide variety of vector-like extensions and their parameter spaces.Comment: 43 pages, 17 figures; v2: text modified to improve readability, references added, journal versio

B-meson signatures of a Supersymmetric U(2) flavor model

We discuss B-meson signatures of a Supersymmetric U(2) flavor model, with relatively light (electroweak scale masses) third generation right-handed scalars. We impose current B and K meson experimental constraints on such a theory, and obtain expectations for B->X_s gamma, B->X_s glue, B->X_s l+ l-, B->phi K_s, B_s-B_sbar mixing, and the dilepton asymmetry in B_s. We show that such a theory is compatible with all current data, and furthermore, could reconcile the apparent deviations from Standard Model predictions that have been found in some experiments.Comment: 37 pages, 21 figures, RevTeX4; v.2 - minor modifications to improve readability. Published versio

Breeding habits of the Indian sheath tailed bat Taphozous longimanus (Hardwicke)

This article does not have an abstract

Studies on the embryology of microchiroptera Part II. Reproduction in the male vespertilionid bat Scotophilus wroughtoni (Thomas)

1. Twenty-nine male specimens of the bat Scotophilus wroughtoni were collected during the different months of the year. Collection were made during two successive years from May 1945 to April 1947. 2. The weight of the testis of these bats increases from the month of December and reaches a maximum weight during February. There is an increase nearly four times in the testis-weight from September to February. 3. The diameter of the seminiferous tubules also increases corresponding to the increase in the testis-weight and progressively vigorous spermatogenetic activity is seen in the germ cells. The diameter of the tubules of the epididymis also increases during' these months. The occurrence of sperms in the tubules of the testis and the epididymis indicates that the breeding season is confined to these months. 4. The males, like the females, probably attain their sexual maturity in their first season,i.e., before they are one year old

Faecal streptococci in fresh frozen shrimp

Present limit of faecal streptococci as 100/g in fresh frozen shrimp was found to be too strict a standard commercially prepared products. Statistical analysis of the data collected indicates that fixing the maximum permissible limit as 1000/g will be a more workable proposition

Construction of temperature compensated constant voltage (VT) curves for super Ni-Cd (tm) cells

Tests to establish current-voltage characteristics at selected temperatures for 9 a-h Super Nickel-Cadmium cells were conducted at Hughes Industrial Electronics Company's Electron Dynamics Division (HIEC/EDD) under sponsorship of NASA/GSFC through their prime spacecraft contractors Fairchild Space (SMEX/SAMPEX) and TRW (TOMSEP). Curves were constructed using techniques established by Webster, Ford, et al, at NASA/GSFC in the late 1960's - early 1970's time period for conventional nickel cadmium cells used on OAO and OSO aircraft. The NASA/GSFC techniques were slightly modified by HIEC/EDD to fit the Super Ni-Cd situation

Right-handed Sneutrinos as Nonthermal Dark Matter

When the minimal supersymmetric standard model is augmented by three right-handed neutrino superfields, one generically predicts that the neutrinos acquire Majorana masses. We postulate that all supersymmetry (SUSY) breaking masses as well as the Majorana masses of the right-handed neutrinos are around the electroweak scale and, motivated by the smallness of neutrino masses, assume that the lightest supersymmetric particle (LSP) is an almost-pure right-handed sneutrino. We discuss the conditions under which this LSP is a successful dark matter candidate. In general, such an LSP has to be nonthermal in order not to overclose the universe, and we find the conditions under which this is indeed the case by comparing the Hubble expansion rate with the rates of the relevant thermalizing processes, including self-annihilation and co-annihilation with other SUSY and standard model particles.Comment: 17 pages v.2: References adde

Safety Recommendations for Evaluation and Surgery of the Head and Neck During the COVID-19 Pandemic

Importance The rapidly expanding novel coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2, has challenged the medical community to an unprecedented degree. Physicians and health care workers are at added risk of exposure and infection during the course of patient care. Because of the rapid spread of this disease through respiratory droplets, health care workers who come in close contact with the upper aerodigestive tract during diagnostic and therapeutic procedures, such as otolaryngologists–head and neck surgeons, are particularly at risk. A set of safety recommendations was created based on a review of the literature and communications with physicians with firsthand knowledge of safety procedures during the COVID-19 pandemic. Observations A high number of health care workers were infected during the first phase of the pandemic in the city of Wuhan, China. Subsequently, by adopting strict safety precautions, other regions were able to achieve high levels of safety for health care workers without jeopardizing the care of patients. The most common procedures related to the examination and treatment of upper aerodigestive tract diseases were reviewed. Each category was reviewed based on the potential risk imposed to health care workers. Specific recommendations were made based on the literature, when available, or consensus best practices. Specific safety recommendations were made for performing tracheostomy in patients with COVID-19. Conclusions and Relevance Preserving a highly skilled health care workforce is a top priority for any community and health care system. Based on the experience of health care systems in Asia and Europe, by following strict safety guidelines, the risk of exposure and infection of health care workers could be greatly reduced while providing high levels of care. The provided recommendations, which may evolve over time, could be used as broad guidance for all health care workers who are involved in the care of patients with COVID-19