2,755 research outputs found
Water resource problems of energy projects in the Colorado River Basin
The successful development of western coal and oil shale deposits
is dependent, to a significant degree, on the availability of adequate
water supplies. EQL is involved in a study of the aggregate effects
of various energy activities in the upper Colorado River Basin on
downstream water quantity and quality. These activities will tend
to reduce the available water in the river, and could increase its
salinity, which is already so high as to interfere with downstream
domestic and agricultural use
Precision Power and Its Application to the Selection of Regression Sample Sizes
Because of contradictions among the various methods, sample size selection in multiple regression has been problematic. For example, how does one reconcile the difference between a 15: 1 subject-to-variable rule and a 30: 1 rule? The purpose of this paper is to analyze the advantages and disadvantages of the various methods of selecting sample sizes in regression. A discussion of the importance of cross-validity to prediction studies will be followed by descriptions of the three categories of sample size methods: cross-validation approaches, rules-of-thumb, and statistical power methods. A rationale will then be developed for the application of precision power to multiple regression, leading to the presentation, through multiple examples, of the precision power method for sample size selection in prediction studies
Economic Value Added and Small Businesses
Economic Value Added (EVA), a tool for creating wealth, is a leading idea in corporate finance today. Highly regarded companies like Coca-Cola and CSX have seen their market value soar since adopting EVA. The concept is straightforward; value is created when earnings exceed the cost of invested capital. Thus, EVA is rapidly gaining acceptance among large, publicly-traded corporations. However, EVA can be applied effectively to create value in small, privately-held firms, too. This article illustrates EVA's application in small, privately-held firms, examines EVA "s strengths and weaknesses, discusses ways to overcome those weaknesses, and describes specific operating, investing and financing actions small business managers can take to create wealth
Pathogen disgust sensitivity and resource scarcity are associated with mate preference for different waist-to-hip ratios, shoulder-to-hip ratios, and body mass index
Environmental factors, such as pathogen prevalence and resource scarcity, are thought to influence mate preferences for traits related to health and resource provisioning potential. Specific body dimensions, such as women's waist-to-hip-ratio (WHR), men’s shoulder-to-hip ratio (SHR), and body mass index (BMI) have also been theorised to be associated with health benefits, or ability to deal with resource scarcity. Here, we test across two studies using different study designs whether the effects of pathogen disgust sensitivity and socioeconomic status (SES; a negative proxy for resource scarcity) on mate preferences extend to men’s WHR preferences, women’s SHR preferences, and both sex’s BMI preferences. Study 1 found that pathogen disgust significantly negatively influenced men’s WHR preference in female bodies, while SES was significantly negatively associated with women’s SHR and BMI preferences in male bodies. Study 2 found that pathogen disgust negatively predicted men’s WHR preference, and positively predicted women’s SHR preference, while SES negatively predicted men’s WHR preference. Our findings support the notion that body shapes are used as cues to health and likelihood of resource provision, and may help explain inconsistencies in the literature regarding variation in body shapes preferences
Progress on the Development of Future Airport Surface Wireless Communications Network
Continuing advances in airport surface management and improvements in airport surface safety are required to enable future growth in air traffic throughout the airspace, as airport arrival and departure delays create a major system bottleneck. These airport management and safety advances will be built upon improved communications, navigation, surveillance, and weather sensing, creating an information environment supporting system automation. The efficient movement of the digital data generated from these systems requires an underlying communications network infrastructure to connect data sources with the intended users with the required quality of service. Current airport surface communications consists primarily of buried copper or fiber cable. Safety related communications with mobile airport surface assets occurs over 25 kHz VHF voice and data channels. The available VHF spectrum, already congested in many areas, will be insufficient to support future data traffic requirements. Therefore, a broadband wireless airport surface communications network is considered a requirement for the future airport component of the air transportation system. Progress has been made on defining the technology and frequency spectrum for the airport surface wireless communications network. The development of a test and demonstration facility and the definition of required testing and standards development are now underway. This paper will review the progress and planned future work
A multivariate approach to human mate preferences
Human mate choice is complicated, with various individual differences and contextual factors influencing preferences for numerous traits. However, focused studies on human mate choice often do not capture this multivariate complexity. Here, we consider multiple factors simultaneously to demonstrate the advantages of a multivariate approach to human mate preferences. Participants (N = 689) rated the attractiveness of opposite-sex online dating profiles that were independently manipulated on facial attractiveness, perceived facial masculinity/femininity, and intelligence. Participants were also randomly instructed to either consider short- or long-term relationships. Using fitness surfaces analyses, we assess the linear and nonlinear effects and interactions of the profiles' facial attractiveness, perceived facial masculinity/femininity, and perceived intelligence on participants' attractiveness ratings. Using hierarchical linear modeling, we were also able to consider the independent contribution of participants' individual differences on their revealed preferences for the manipulated traits. These individual differences included participants' age, socioeconomic status, education, disgust (moral, sexual, and pathogen), sociosexual orientation, personality variables, masculinity, and mate value. Together, our results illuminate various previously undetectable phenomena, including nonlinear preference functions and interactions with individual differences. More broadly, the study illustrates the value of considering both individual variation and population-level measures when addressing questions of sexual selection, and demonstrates the utility of multivariate approaches to complement focused studies
Maturation and Reproduction of Shovelnose Sturgeon in the Middle Mississippi River
Shovelnose sturgeon Scaphirhynchus platorynchus in the middle Mississippi River provide one of the last commercially viable sturgeon fisheries in the world, yet their maturation and reproduction have not been linked. During 2005 and 2006, we sampled adult and age-0 shovelnose sturgeon to link age at maturation, the timing and periodicity of spawning, age-0 sturgeon production, and the resulting age-0 growth rates. Age at maturity was later than previous estimates, the minimum age of first maturation being 8 years for males and 9 years for females. Total egg count was slightly lower than previously reported (mean = 29,573 per female; SE = 2,472). Males and females typically spawned every 2 and 3 years, respectively. Peaks in mature fish coincided with rising river stages and water temperatures at which shovelnose sturgeon probably spawn. Peaks in spent adults followed. Age-0 shovelnose sturgeon occurred during June and July 2005 and May and June 2006, confirming successful spawning. Age-0 sturgeon grew between 0.69 and 1.69 mm total length/d; four distinct weekly cohorts occurred each year. During fall 2006, females contained ripe eggs, males were milting, and a single age-0 sturgeon (total length = 55 mm) was captured, suggesting that shovelnose sturgeon spawn during fall as well as spring. Management must consider the protracted nature of spawning within seasons as well as differences in spawning activity between seasons
Alteration of Gene Expression Signatures of Cortical Differentiation and Wound Response in Lethal Clear Cell Renal Cell Carcinomas
Clear cell renal cell carcinoma (ccRCC) is the most common malignancy of the adult kidney and displays heterogeneity in clinical outcomes. Through comprehensive gene expression profiling, we have identified previously a set of transcripts that predict survival following nephrectomy independent of tumor stage, grade, and performance status. These transcripts, designated as the SPC (supervised principal components) gene set, show no apparent biological or genetic features that provide insight into renal carcinogenesis or tumor progression. We explored the relationship of this gene list to a set of genes expressed in different anatomical segments of the normal kidney including the cortex (cortex gene set) and the glomerulus (glomerulus gene set), and a gene set expressed after serum stimulation of quiescent fibroblasts (the core serum response or CSR gene set). Interestingly, the normal cortex, glomerulus (part of the normal renal cortex), and CSR gene sets captured more than 1/5 of the genes in the highly prognostic SPC gene set. Based on gene expression patterns alone, the SPC gene set could be used to sort samples from normal adult kidneys by the anatomical regions from which they were dissected. Tumors whose gene expression profiles most resembled the normal renal cortex or glomerulus showed better survival than those that did not, and those with expression features more similar to CSR showed poorer survival. While the cortex, glomerulus, and CSR signatures predicted survival independent of traditional clinical parameters, they were not independent of the SPC gene list. Our findings suggest that critical biological features of lethal ccRCC include loss of normal cortical differentiation and activation of programs associated with wound healing
Amputation and advance care plans:an observational study exploring decision-making and long-term outcomes in a vascular centre
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