472 research outputs found
ASYMMETRIC PRICE RELATIONSHIPS IN THE U.S. BROILER INDUSTRY
This study presents a testing methodology to analyze potential price asymmetries among the farm, wholesale, and retail levels of the U.S. broiler industry. Lag length, direction of causality and power of the integrators in the industry have allowed the wholesale price to become the center, causal price in the market. Asymmetric price transmissions, however, are limited. While downward movements in the wholesale price are passed on more fully to growers than increases in the wholesale price, only consumers in the North Central region of the U.S. share a larger portion of wholesalers' price increases than price decreases.Asymmetry, Broilers, Concentration, Granger causality, Price transmission, Demand and Price Analysis, Livestock Production/Industries,
Trends in the Black-White Achievement Gap:Clarifying the Meaning of Within- and Between-School Achievement Gaps
We decompose black-white achievement gap trends between 1971 and 2004 into trends in within- and between-school differences. We show that the previous finding that narrowing within-school inequality explains most of the decline in the black-white achievement gap between 1971 and 1988 is sensitive to methodology. Employing a more detailed partition of achievement differences, we estimate that 40 percent of the narrowing of the gap through the 1970s and 1980s is attributable to the narrowing of within-school differences between black and white students. Further, the consequences for achievement of attending a high minority school became increasingly deleterious between 1971 and 1999.
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Draft Genome of a Type 4 Pilus Defective Myxococcus xanthus Strain, DZF1
Myxococcus xanthus is a member of the Myxococcales order within the deltaproteobacterial subdivision. Here, we report the whole-genome shotgun sequence of the type IV pilus (T4P) defective strain DZF1, which includes many genes found in strain DZ2 but absent from strain DK1622
Prediagnostic use of hormone therapy and mortality after breast cancer.
BACKGROUND: A few studies have observed reduced breast cancer mortality in women who used hormone therapy before diagnosis. Due to the high prevalence of past and current hormone use, it is important to investigate whether these preparations are related to breast cancer mortality. METHODS: To evaluate the influence of prediagnostic use of hormone therapy on breast cancer mortality, a prospective cohort of 12,269 women ages 50 years or more diagnosed with incident invasive breast cancer and residents of Wisconsin, Massachusetts, or New Hampshire were enrolled in three phases beginning in 1988. They were followed for death until December 31, 2005, using the National Death Index. Cumulative mortality and multivariable adjusted hazard rate ratios for breast cancer and other mortality causes were calculated for women according to any hormone therapy use, and for exclusive use of estrogen or estrogen-progestin (EP). RESULTS: During an average 10.3 years of follow-up, 1,690 deaths from breast cancer were documented. Cumulative mortality from breast cancer was lower among hormone therapy users, specifically current users at the time of diagnosis, and EP users, compared with nonusers. Adjusted survival varied by type and duration of hormone therapy before diagnosis. A reduced risk of death from breast cancer was associated with EP preparations (hazard rate ratio, 0.73; 0.59-0.91) and with > or =5 years of EP use (0.60; 0.43-0.84). No association was observed for women who were former or current users of E-alone preparations. CONCLUSIONS: Although use of combined EP preparations increases breast cancer risk, in this study, use of these hormones before diagnosis was associated with reduced risk of death after a breast cancer diagnosis. The better survival among users, particularly of EP, persisted after adjustment of screening, stage, and measured confounders
Cigarette Smoking Before and After Breast Cancer Diagnosis: Mortality From Breast Cancer and Smoking-Related Diseases
Cigarette smoking increases overall mortality, but it is not established whether smoking is associated with breast cancer prognosis
Adherence to the Mediterranean Diet and Incidence of Pre-Frailty and Frailty in Community-Dwelling Adults 70+: The 3-Year DO-HEALTH Study
The Mediterranean diet has been associated with many health benefits. Therefore, we investigated whether the degree of adherence to the Mediterranean diet at baseline, or changes in adherence over time, were associated with the incidence of pre-frailty or frailty in generally healthy older adults. This study used the DO-HEALTH trial data. We evaluated Mediterranean diet adherence with Panagiotakos’ MedDietScore at baseline and at 3-year follow-up; frailty was assessed annually with the Fried frailty phenotype. We used minimally and fully adjusted mixed logistic regression models to estimate the exposure–disease relationship. We included 1811 participants without frailty at baseline (mean age 74.7 years; 59.4% women). Baseline adherence, as reflected by the MedDietScore, was not associated with becoming pre-frail [OR(95%CI) = 0.93 (0.83–1.03) for five-point greater adherence] or frail [OR(95%CI) = 0.90 (0.73–1.12) for five points]. However, a five-point increase in the MedDietScore over three years was associated with lower odds of becoming pre-frail [OR(95%CI) = 0.77 (0.68–0.88)] and frail [OR(95%CI) = 0.77 (0.64–0.92)]. In generally healthy and active older adults, baseline adherence to the Mediterranean diet was not associated with the incidence of pre-frailty or frailty over a 3-year follow-up. However, improved adherence to the Mediterranean diet over time was associated with significantly lower odds of becoming pre-frail or frail
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Draft Genome Sequence of Myxococcus xanthus Wild-Type Strain DZ2, a Model Organism for Predation and Development
Myxococcus xanthus is a member of the Myxococcales order within the Deltaproteobacteria subdivision. The myxobacteria reside in soil, have relatively large genomes, and display complex life cycles. Here, we report the whole-genome shotgun sequence of strain DZ2, which includes unique genes not found previously in strain DK1622
Rationales for the Lightning Flight-Commit Criteria
Since natural and artificially-initiated (or "triggered") lightning are demonstrated hazards to the launch of space vehicles, the American space program has responded by establishing a set of Lightning Flight Commit Criteria (LFCC), also known as Lightning Launch Commit Criteria (LLCC), and associated Definitions to mitigate the risk. The LLCC apply to all Federal Government ranges and similar LFCC have been adopted by the Federal Aviation Administration for application at state-operated and private spaceports. The LLCC and Definitions have been developed, reviewed, and approved over the years of the American space program, progressing from relatively simple rules in the mid-twentieth century (that were inadequate) to a complex suite for launch operations in the early 21st century. During this evolutionary process, a "Lightning Advisory Panel (LAP)" of top American scientists in the field of atmospheric electricity was established to guide it. Details of this process are provided in a companion document entitled "A History of the Lightning Launch Commit Criteria and the Lightning Advisory Panel for America s Space program" which is available as NASA Special Publication 2010-216283. As new knowledge and additional operational experience have been gained, the LFCC/LLCC have been updated to preserve or increase their safety and to increase launch availability. All launches of both manned and unmanned vehicles at all Federal Government ranges now use the same rules. This simplifies their application and minimizes the cost of the weather infrastructure to support them. Vehicle operators and Range safety personnel have requested that the LAP provide a detailed written rationale for each of the LFCC so that they may better understand and appreciate the scientific and operational justifications for them. This document provides the requested rationale
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Dietary fiber intake and mortality among survivors of myocardial infarction: prospective cohort study
Objective: To evaluate the associations of dietary fiber after myocardial infarction (MI) and changes in dietary fiber intake from before to after MI with all cause and cardiovascular mortality. Design: Prospective cohort study. Setting: Two large prospective cohort studies of US women and men with repeated dietary measurements: the Nurses’ Health Study and the Health Professionals Follow-Up Study. Participants: 2258 women and 1840 men who were free of cardiovascular disease, stroke, or cancer at enrollment, survived a first MI during follow-up, were free of stroke at the time of initial onset of MI, and provided food frequency questionnaires pre-MI and at least one post-MI. Main outcome measures Associations of dietary fiber post-MI and changes from before to after MI with all cause and cardiovascular mortality using Cox proportional hazards models, adjusting for drug use, medical history, and lifestyle factors. Results: Higher post-MI fiber intake was significantly associated with lower all cause mortality (comparing extreme fifths, pooled hazard ratio 0.75, 95% confidence interval 0.58 to 0.97). Greater intake of cereal fiber was more strongly associated with all cause mortality (pooled hazard ratio 0.73, 0.58 to 0.91) than were other sources of dietary fiber. Increased fiber intake from before to after MI was significantly associated with lower all cause mortality (pooled hazard ratio 0.69, 0.55 to 0.87). Conclusions: In this prospective study of patients who survived MI, a greater intake of dietary fiber after MI, especially cereal fiber, was inversely associated with all cause mortality. In addition, increasing consumption of fiber from before to after MI was significantly associated with lower all cause and cardiovascular mortality
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