“Do one, teach one” : the new paradigm in general surgery residency training

Peer reviewedPreprin

Perceptions of Teachers and Students of School Effectiveness Factors at Knoxville High School

This field study was designed to investigate teacher and student perceptions of school effectiveness factors as related to Knoxville High School. Specifically, this study compared actual perceived school effectiveness factors between teachers and students. A comparison of past achievement tests was also initiated to determine what effect, if any, school leadership might play in the process. Two instruments were designed for this study, Teacher Feedback Survey and the Student Opinion Survey. Dr. David Bartz, of Eastern Illinois University, developed the survey instruments based on research conducted by Edmonds, Brookover, Lezotte and Weber and a review of current literature addressing the issue of identifying school effectiveness factors. Thirty-three teachers and four hundred and thirty-six students provided the data for the study. Responses to the surveys were scored at the computer center at Eastern Illinois University. This field study was divided into five chapters. Chapter One explains the problem and limitations of the study. Chapter Two presents a study of the research and related literature specific to school effectiveness factors. Chapter Three describes the design of the study, method of data collection and instrumentation, and method of data analysis. Chapter Four lists the results, conclusions, and recommendations of the data collected from the two surveys and prior achievement testing results. Chapter Five summarizes the recommendations of the researcher based upon survey results

An application of Markov chains

Thesis (M.A.)--Boston UniversityProbability problems in which a time parameter is involved are known as stochastic processes. The simplest time dependent stochastic processes are those in which the probabilities of a system changing to various states are solely dependent upon the present state of the system. These processes are known as Markov processes, or for the case where only discrete time intervals are considered, as Markov chains. A Markov chain may be completely defined by the matrix of its transition probabilities. This matrix is called a stochastic matrix and is characterized by the facts that it is a square matrix, that the elements of each column sum to one and that all the elements are non-negative. An important consideration in most Markov chain problems is the effect of a number of transitions as defined by the stochastic matrix. Performing this operation requires determining the higher powers of the stochastic matrix. Two modal matrices are defined, where k is the matrix of the column characteristic vectors of the stochastic matrix and K is the matrix of the row characteristic vectors. It is shown that with proper normalization of these vectors, the stochastic matrix P is equal to kAK, where A is the matrix of the characteristic roots along the diagonal and zeroes elsewhere. .The higher powers of the stochastic matrix, Pm, are then found to be equal to kAmk. The stochastic matrix is found always to have a characteristic root one, and all the other roots are shown to be less than one in absolute value. The limiting transition matrix P ∞ is found to have identical columns, each consisting of the characteristic column vector associated with the characteristic root one. The limiting distribution is the same vector and is independent of the initial conditions.[TRUNCATED

Reduction of niobium pentoxide by carbon

The investigations of the reduction of niobium pentoxide by carbon showed that niobium metal could be prepared by a direct reduction. High temperatures in the region of 2000°C but below the melting point of niobium and dynamic vacuum of one micron or less were the principal experimental conditions employed throughout the course of this study. The reaction, which followed very closely the stoichiometry of the equation Nb2o5 +5C ---\u3e 2Nb + 5CO, began at a temperature near 1200°C and was nearly completed at 1600°C. The data indicated that it might be possible to allow reduction to take place at approximately 1800°C. After the reaction is completed at this temperature, raising of the temperature of the reaction material to nearly 2000°C might eliminate residual oxygen as a result of volatilization of a lower oxide of niobium

Draft genome sequence of Staphylococcus aureus 1608, a strain that caused toxic mastitis in twin cows

Staphylococcus aureus 1608 is a strain that caused a lethal mastitis in cows. Here, the draft genome sequence of the strain is presented

Unraveling the Genotypic and Phenotypic Diversity of the Psychrophilic Clostridium estertheticum Complex, a Meat Spoilage Agent

The spoilage of vacuum-packed meat by Clostridium estertheticum complex (CEC), which is accompanied by or without production of copious amounts of gas, has been linked to the acetone–butyrate–ethanol fermentation, but the mechanism behind the variable gas production has not been fully elucidated. The reconstruction and comparison of intra- and interspecies metabolic pathways linked to meat spoilage at the genomic level can unravel the genetic basis for the variable phenotype. However, this is hindered by unavailability of CEC genomes, which in addition, has hampered the determination of genetic diversity and its drivers within CEC. Therefore, the current study aimed at determining the diversity of CEC through comprehensive comparative genomics. Fifty CEC genomes from 11 CEC species were compared. Recombination and gene gain/loss events were identified as important sources of natural variation within CEC, with the latter being pronounced in genomospecies2 that has lost genes related to flagellar assembly and signaling. Pan-genome analysis revealed variations in carbohydrate metabolic and hydrogenases genes within the complex. Variable inter- and intraspecies gas production in meat by C. estertheticum and Clostridium tagluense were associated with the distribution of the [NiFe]-hydrogenase hyp gene cluster whose absence or presence was associated with occurrence or lack of pack distention, respectively. Through comparative genomics, we have shown CEC species exhibit high genetic diversity that can be partly attributed to recombination and gene gain/loss events. We have also shown genetic basis for variable gas production in meat can be attributed to the presence/absence of the hyp gene cluster