Disorder Enhanced Spin Polarization in Diluted Magnetic Semiconductors

We present a theoretical study of diluted magnetic semiconductors that includes spin-orbit coupling within a realistic host band structure and treats explicitly the effects of disorder due to randomly substituted Mn ions. While spin-orbit coupling reduces the spin polarization by mixing different spin states in the valence bands, we find that disorder from Mn ions enhances the spin polarization due to formation of ferromagnetic impurity clusters and impurity bound states. The disorder leads to large effects on the hole carriers which form impurity bands as well as hybridizing with the valence band. For Mn doping 0.01 < x < 0.04, the system is metallic with a large effective mass and low mobility

Phenomenology of the Baryon Resonance 70-plet at Large N_c

We examine the multiplet structure and decay channels of baryon resonances in the large N_c QCD generalization of the N_c = 3 SU(6) spin-flavor 70. We show that this ``70'', while a construct of large N_c quark models, actually consists of five model-independent irreducible spin-flavor multiplets in the large N_c limit. The preferred decay modes for these resonances fundamentally depend upon which of the five multiplets to which the resonance belongs. For example, there exists an SU(3) ``8'' of resonances that is eta-philic and pi-phobic, and an ``8'' that is the reverse. Moreover, resonances with a strong SU(3) ``1'' component prefer to decay via a K-bar rather than via a pi. Remarkably, available data appears to bear out these conclusions.Comment: 26 pages, ReVTe

Glaucoma Screening in the Haitian Afro-Caribbean Population of South Florida

Objective: To evaluate the presence of clinical signs consistent with suspected glaucoma in Haitian Afro-Caribbean individuals residing in South Florida who do not receive regular eye examinations. Design: Retrospective, cross-sectional study. Methods: SETTING: Community health center in the Little Haiti district of Miami, Florida. PATIENT POPULATION: We reviewed medical records and screening forms from five health screenings between October 2011 to October 2013 of 939 Afro-Caribbean individuals older than 18 years, who were never diagnosed with glaucoma or had an eye examination within the last ten years. PROCEDURES: Measurements of distance visual acuity (VA), intraocular eye pressure (IOP), central corneal thickness (CCT), cup-to-disc ratio (CDR), frequency doubling technology (FDT) perimeter visual field (VF). Main Outcome Measures: Proportion of glaucoma suspects, based on IOP greater than or equal to 24 mm Hg or CDR greater than or equal to 0.7 in either eye, and determinants of CDR and IOP. Results: One hundred ninety-one (25.5%) of 750 patients were identified as glaucoma suspects. Glaucoma suspects were common in both the youngest and oldest age groups (70 years, 25.0%; 95% CI, 21.8–28.2) and higher in men than women less than 70 years; the reverse was true after 70 years. Among all patients, mean IOP was 19.2±4.5 mmHg, mean CDR was 0.37±0.17, and mean CCT was 532±37.1 µm. In multiple linear stepwise regression analysis, determinates of increased CDR included increasing age (P = 0.004), lack of insurance (P = 0.019), and higher IOP (P<0.001), while increasing CDR (P<0.001) and thicker CCT (P<0.001) were associated with higher IOP. Conclusions: This first glaucoma survey in a U.S. Haitian Afro-Caribbean population indicates glaucoma suspect status is high across all age groups, and suggests glaucoma monitoring in people less than 40 years of age is indicated in this population

British entrepreneurs and industrial revolution cost management: a study of innovation

Traditional accounting histories date the advent of sophisticated cost accounting from the mid-1880\u27s and credit American innovators of Frederick Taylor\u27s scientific management movement with conceiving the new practices. However, it is counterintuitive to think the entrepreneurs of the British Industrial Revolution would not have developed costing techniques, given their significant methodological advances in other economic areas, such as technology, capital accumulation, and marketing structure development. This paper reports the findings from a survey of surviving business records from twenty-five large industrial firms during the 1760-1850 period, concentrated in the dominant textile and iron industries. Substantial evidence of mature cost management has been found in eight major areas of activity

Dietary treatment of Crohn’s disease: perceptions of families with children treated by exclusive enteral nutrition, a questionnaire survey

Background: Diet is strongly associated with the aetiology of Crohn’s Disease (CD) and exclusive enteral nutrition (EEN) is the primary induction treatment in paediatric CD. This study explored opinions around the use of EEN and alternative novel, solid food-based diets (SFDs) expressed by paediatric patients with CD, previously treated with EEN and their parents. Methods: This anonymous questionnaire surveyed families of CD patients treated with EEN over 1 year. Two questionnaire forms were completed; one asking the patients’ opinions and another referring to their main carer. This questionnaire explored participants’ demographic characteristics; acceptability of a repeat EEN course to treat a future flare (EEN repeat); their opinion on how difficult EEN would be compared to an example SFD; and their intention to participate in a future clinical trial assessing the therapeutic efficacy of an SFD in CD. Results: Forty-one families of CD patients were approached with 29 sending replies (71%). Most of our participants were positive on completing another EEN course, however the majority would choose an SFD alternative (Patients: 66, Parents:72%). Both patients and their parents rated EEN to be more difficult to adhere to compared to an example SFD (p &lt; 0.05), and their ratings were strongly correlated (EEN:r = 0.83, SFD:r = 0.75, p &lt; 0.001). The majority of our respondents would agree to participate in a clinical trial assessing an SFD’s effectiveness (Patients:79, Parents:72%) for the management of active CD. Conclusions: While patients with CD and their families would accept an EEN repeat, the majority would prefer an SFD alternative. CD families surveyed are supportive of the development of solid food-based dietary treatments

Efficient Computation of Probabilities of Events Described by Order Statistics and Application to a Problem of Queues

Consider a set of N i.i.d. random variables in [0, 1]. When the experimental values of the random variables are arranged in ascending order from smallest to largest, one has the order statistics of the set of random variables. In this note an O(N3) algorithm is developed for computing the probability that the order statistics vector lies in a given rectangle. The new algorithm is then applied to a problem of statistical inference in queues. Illustrative computational results are included

Efficient Computation of Probabilities of Events Described by Order Statistics and Applications to Queue Inference

This paper derives recursive algorithms for efficiently computing event probabilities related to order statistics and applies the results in a queue inferencing setting. Consider a set of N i.i.d. random variables in [0, 1]. When the experimental values of the random variables are arranged in ascending order from smallest to largest, one has the order statistics of the set of random variables. Both a forward and a backward recursive O(N3 ) algorithm are developed for computing the probability that the order statistics vector lies in a given N-rectangle. The new algorithms have applicability in inferring the statistical behavior of Poisson arrival queues, given only the start and stop times of service of all N customers served in a period of continuous congestion. The queue inference results extend the theory of the "Queue Inference Engine" (QIE), originally developed by Larson in 1990 [8]. The methodology is extended to a third O(N 3 ) algorithm, employing both forward and backward recursion, that computes the conditional probability that a random customer of the N served waited in queue less than r minutes, given the observed customer departure times and assuming first come, first served service. To our knowledge, this result is the first O(N3 ) exact algorithm for computing points on the in-queue waiting time distribution function,conditioned on the start and stop time data. The paper concludes with an extension to the computation of certain correlations of in-queue waiting times. Illustrative computational results are included throughout