Can a Newly Proposed Mechanism for Allocating Contracts in U.S. Electricity Wholesale Markets Lead to Lower Prices? A Game Theoretic Analysis

This study of the wholesale electricity market compares the cost-minimizing performance of the auction mechanism currently in place in U.S. markets with the performance of a proposed replacement. The current mechanism chooses an allocation of contracts that minimizes a fictional cost calculated using pay-as-offer pricing. Then suppliers are paid the market clearing price. The proposed mechanism uses the market clearing price in the allocation phase as well as in the payment phase. In concentrated markets, the proposed mechanism outperforms the current mechanism even when strategic behavior by suppliers is taken into account. The advantage of the proposed mechanism increases with increased price competition.

Carcinoma of the lower uterine segment: A newly described association with Lynch Syndrome

Purpose. We performed a case-comparison study to describe the characteristics of LUS tumors and their association with risk factors for endometrial cancer. ^ Patients and Methods. From January 1996 through October 2007, 3,892 women were identified with a diagnosis of primary endometrial carcinoma or primary cervical adenocarcinoma. Pathology records from the 1,009 women who had a hysterectomy were reviewed. Subjects were included in the LUS group only if the tumor was clearly originating from the area between the lower corpus and upper cervix in the hysterectomy specimen. The LUS group was compared to all patients with endometrial corpus carcinoma who underwent hysterectomy at our institution in a 12-month period randomly selected from the study period. Risk factors for endometrial carcinoma such as body mass index (BMI) and Lynch Syndrome were assessed. Expression of estrogen receptor (ER), vimentin, carcinoembryonic antigen (CEA), p16, and human papilloma virus DNA (HPV DNA) was assessed; this panel is known to be effective in distinguishing adenocarcinomas of endometrial versus endocervical origin. Fisher's Exact, Chi-square, Mann-Whitney, and Student's t-tests were utilized for statistical analysis. ^ Results. Thirty-five of 1,009 women had endometrial carcinoma of the LUS (3.5%; 95% CI: 2–4%). Compared to patients with corpus tumors, LUS patients were younger (54.2 vs. 62.9 years, P = .001), had higher stage (P < .001), and more invasive tumors (P = .001). Preoperative diagnosis of the LUS tumors more frequently included the possibility of endocervical adenocarcinoma ( P < .001), leading to preoperative radiation therapy in 4 patients. Median BMI was similar in the LUS and corpus groups. Seventy-three percent of the available LUS tumors had a similar immunohistochemical expression pattern to conventional endometrioid adenocarcinoma. Because of the young median age for the LUS group, we performed immunohistochemistry for Lynch syndrome-associated DNA mismatch repair proteins MLH1, MSH2, MSH6, and PMS2. Microsatellite instability testing (MSI) and MLH1 promoter hypermethylation were performed when indicated. Thirty-six percent of the LUS tumors were MSI-high. Ten of thirty-five (29%) women with LUS tumors were either confirmed to have Lynch Syndrome or were strongly suspected to have Lynch Syndrome based on tissue-based molecular assays (95% CI, 16 to 45%). ^ Conclusions. Endometrial carcinoma arising in the LUS is a clinical and pathologic entity which can be diagnostically confused with cervical adenocarcinoma. In general, LUS tumors can be correctly identified as being endometrial carcinoma using the immunohistochemical panel noted above. The prevalence of Lynch Syndrome in patients with LUS tumors is much greater than that of the general endometrial cancer population (1.8%) or in endometrial cancer patients younger than 50 years of age (8–9%). Based on our results, the possibility of Lynch Syndrome should be considered in women with LUS tumors. ^

Occupational performance of Mexican Americans with end-stage-renal-disease living on dialysis in the lower Rio Grande Valley

The number of people with end-stage-renal-disease (ESRD) and living with dialysis is a growing public health concern. Most studies about the impact of ESRD on people’s lives have placed attention on the medical and clinical dimension of ESRD. Very few have given attention to the environmental and cultural context in which people with ESRD live, the adaptation that these individuals must make to adjust to living with ESRD and dialysis, or the occupations in which they engage. Additionally these studies have not focused on Mexican Americans who are disproportionately affected by this illness and condition. This qualitative study explores the needs, perceptions, and issues facing Mexican Americans with ESRD living with dialysis as well as their families. Participants were residents of the Lower Rio Grande Valley and included individuals with ESRD, family members, and the healthcare providers who give care to them. The Health Belief Model and Lifestyle Performance Model served as the theoretical frameworks. The study also explored the daily occupations of this population. ^ In-depth interviews were conducted on 15 Mexican Americans with ESRD living with dialysis, 15 family members, and six dialysis healthcare providers. A video documentary of the day-to-day life of three individuals with ESRD and their families was produced. Such data do not currently exist and will greatly enhance the understanding of the human experience of living with ESRD. The results suggest that a collective effort of the family unit is at work to deal with the demands of dialysis. An imbalance and disharmony exist among the occupational activities, which creates occupational deprivation and disruption for both the individuals and family members. Implications for practice and recommendations for further research are described. ^

Relationship between parental feeding practices and weight status in a lower socioeconomic pre-school population

High prevalence of overweight and obesity among preschool children in the low income population is consistently documented in research with one of every seven low-income, preschool-aged children classified as obese. Parental feeding practices have the potential to be contributing factors to the obesity epidemic. However, the impact of parental feeding practices on obesity in preschool age children has not been well explored. The purpose of this study was to determine relationships between the parental feeding practices of using dessert, sweets or candy as a reward for finishing foods, restricting dessert if the child does not finish their plate at dinner, asking the child to consume everything on their plate at dinner, and having family dinners to obesity in low income, preschool age children.^ A cross-sectional secondary data analysis was completed using the STATA 11 statistical software. Descriptive statistics were completed to summarize demographic and BMI data of participants, as well as parental feeding behavior variables. Pearson’s correlation was implemented to determine a correlation between parental feeding behavior variables and BMI z scores. Predictive relationships between the variables were explored through multivariable linear regression analysis. Regression analyses were also completed factoring in the confounders of gender, age, and ethnicity.^ Results revealed (1) no significant correlations or predictive trends between the use of rewards, forced consumption, or family dinner and BMI in low income preschool age children, and (2) a significant negative correlation and predictive trend between restriction of desserts and BMI in low income preschool age children. Since the analysis supported the null hypothesis for the practices of reward use, forced consumption, and family dinner, these practices are not considered risk factors for obese level BMIs. The inverse association found for practice of restriction and BMI suggests it is unnecessary to discourage parents from using restriction. Limitations of the study included the sample size, reliability of the answers provided on the Healthy Home Survey by participant guardians, and generalizability of the sample to the larger population.^

Confidential inquiry into perinatal mortality in the Lower Rio Grande Valley, 1988

A review of 1985 neonatal death statistics in the Lower Rio Grande Valley of Texas revealed an excessive perinatal death rate among Hispanics compared to Anglos. In order to identify factors contributing to perinatal mortality in the region and to determine if existing perinatal services were adequate, a confidential inquiry into each 1988 perinatal death was performed.^ Medical risk factors in the mothers were infrequent. The most commonly noted pregnancy complication was polyhydramnios. This complication is often associated with anencephalus which was the most frequent birth anomaly detected in the region.^ The study results did not reveal an association between lay midwife deliveries in the region and excessive perinatal mortality nor did perinatal mortality appear to be associated with a lack of neonatal intensive care facilities. Lack of prenatal care was the most commonly encountered preventable factor associated with perinatal death. It was not possible to determine if the level of care for Anglos and Hispanics differed because of the low number of Anglo deaths although the socioeconomic level of deaths in each of the ethnic groups was the same. ^

RESPIRATORY COMPENSATION MECHANISMS IN THE UPPER AND LOWER RESPIRATORY TRACTS OF AN ANIMAL MODEL AFTER SUBCHRONIC INHALATION EXPOSURE TO FORMALDEHYDE: IMPLICATIONS FOR TOXICOLOGY RISK ASSESSMENT (DEPOSITION, DOSE RECEIVED, RESPONSE)

The potential for significant human populations to experience long-term inhalation of formaldehyde and reports of symptomatology due to this exposure has led to a considerable interest in the toxicologic assessment of risk from subchronic formaldehyde exposures using animal models. Since formaldehyde inhalation depresses certain respiratory parameters in addition to its other forms of toxicity, there is a potential for the alteration of the actual dose received by the exposed individual (and the resulting toxicity) due to this respiratory effect. The respiratory responses to formaldehyde inhalation and the subsequent pattern of deposition were therefore investigated in animals that had received subchronic exposure to the compound, and the potential for changes in the formaldehyde dose received due to long-term inhalation evaluated. Male Sprague-Dawley rats were exposed to either 0, 0.5, 3, or 15 ppm formaldehyde for 6 hours/day, 5 days/week for up to 6 months. The patterns of respiratory response, deposition and the compensation mechanisms involved were then determined in a series of formaldehyde test challenges to both the upper and to the lower respiratory tracts in separate groups of subchronically exposed animals and age-specific controls (four concentration groups, two time points). In both the control and pre-exposed animals, there was a characteristic recovery of respiratory parameters initially depressed by formaldehyde inhalation to at or approaching pre-exposure levels within 10 minutes of the initiation of exposure. Also, formaldehyde deposition was found to remain very high in the upper and lower tracts after long-term exposure. Therefore, there was probably little subsequent effect on the dose received by the exposed individual that was attributable to the repeated exposures. There was a diminished initial minute volume response in test challenges of both the upper and lower tracts of animals that had received at least 16 weeks of exposure to 15 ppm, with compensatory increases in tidal volume in the upper tract and respiratory rate in the lower tract. However, this dose-related effect was probably not relevant to human risk estimation because this formaldehyde dose is in excess of that experienced by human populations. ^

(Table 1) Geochemistry of realatively fresh rocks of ODP Sites 127-794 and 127-797

The flows and sills drilled at Sites 794 and 797 in the Yamato Basin of the Japan Sea are subalkalic, olivine, and/or plagioclase phyric basalts. Compositionally, the rocks can be divided into a depleted, low-K type and an enriched, relatively high-K type. In addition, two contrasting evolution trends are reflected in the rock compositions, which allow four different magmatic suites to be identified. It is suggested that the depleted or enriched nature of these suites represent primary characteristics, while the different evolution trends are related to fractionation processes in crustal magma chambers. A tholeiitic evolution trend, with increasing FeO and TiO2 and decreasing Al2O3, can be modelled by fractional crystallization of 40%-50% plagioclase, olivine, and augite. A mildly calc-alkalic evolution trend, with decreasing FeO, increasing Al2O3, and nearly constant TiO2, can be modelled by 8%-12% olivine fractionation. Mineralogical evidence suggests that these differences may be related to the effect of small amounts of water during crystallization of the calc-alkalic suites. The tholeiitic suites occur in the lower parts of the drill cores, while the calc-alkalic suites occur in the upper parts. This suggests a complex tectonic and magmatic evolution, perhaps reflecting a transition between calc-alkalic magmatism related to subduction zone activity and tholeiitic magmatism related to back-arc spreading. Furthermore, any magmatic model must be able to account for the range in parental magmas from depleted to enriched throughout the tectonic history of the Yamato Basin.

Mineral resources in Lower Brule Indian Reservation

On the Lower Brule Indian Reservation in South Dakota, about 3 million tons of metallic manganese are in low-grade deposits in the DeGrey Member of the Pierre Shale on the reservation. The geology and methods of mining and processing this sub-economic mineral resource have been studied extensively; technologically, extraction of manganese is possible. However, an efficient, economical method to separate manganese-bearing nodules from the shale host rocks has yet to be found. The manganiferous nodules occur in the Oacoma zone of the Sully shale member (De-Grey Member) which is a subdivision of the South Dakota Pierre Shale formation. These nodular deposits have an interesting similarity in stratigraphical position, lithology and manganese content to those of the Porcupine Mountain area in Manitoba.

Chemical analysis and argon geochronology from dive SAR_1 on Cornacya seamount of the Sardinia Channel

Sarcya 1 dive explored a previously unknown 12 My old submerged volcano, labelled Cornacya. A well developed fracturation is characterised by the following directions: N 170 to N-S, N 20 to N 40, N 90 to N 120, N 50 to N 70, which corresponds to the fracturation pattern of the Sardinian margin. The sampled lavas exhibit features of shoshonitic suites of intermediate composition and include amphibole-and mica-bearing lamprophyric xenoliths which are geochemically similar to Ti-poor lamproites. Mica compositions reflect chemical exchanges between the lamprophyre and its shoshonitic host rock suggesting their simultaneous emplacement. Nd compositions of the Cornacya K-rich suite indicate that continental crust was largely involved in the genesis of these rocks. The spatial association of the lamprophyre with the shoshonitic rocks is geochemically similar to K-rich and TiO2-poor igneous suites, emplaced in post-collisional settings. Among shoshonitic rocks, sample SAR 1-01 has been dated at 12.6±0.3 My using the 40Ar/39Ar method with a laser microprobe on single grains. The age of the Cornacya shoshonitic suite is similar to that of the Sisco lamprophyre from Corsica, which similarly is located on the western margin of the Tyrrhenian Sea. Thus, the Cornacya shoshonitic rocks and their lamprophyric xenolith and the Sisco lamprophyre could represent post-collisional suites emplaced during the lithospheric extension of the Corsica-Sardinia block, just after its rotation and before the Tyrrhenian sea opening. Drilling on the Sardinia margin (ODP Leg 107) shows that the upper levels of the present day margin (Hole 654) suffered tectonic subsidence before the lower part (Hole 652). The structure of this lower part is interpreted as the result of an eastward migration of the extension during Late Miocene and Early Pliocene times. Data of Cornacya volcano are in good agreement with this model and provide good chronological constraints for the beginning of the phenomenon.

Geochemistry of Cretaceous sills and lava flows of ODP Holes 129-800A and 129-802A

On the basis of their respective eruptive environments and chemical characteristics, alkalic dolerite sills from the northern Pigafetta Basin (Site 800) and tholeiitic pillow lavas from the Mariana Basin (Site 802) sampled during Ocean Drilling Program Leg 129 are considered to represent examples of the widespread mid-Cretaceous volcanic event in the western Pacific. Both groups of basic rocks feature mild, low-grade, anoxic smectite-celadonite-carbonate-pyrite alteration; late-stage oxidation is very limited in extent, with the exception of the uppermost sill unit at Site 800. The aphyric and nonvesicular Site 800 alkalic dolerite sills are all well-evolved mineralogically and chemically, being mainly of hawaiite composition, and are similar to ocean island basalts. They are characterized by high contents of incompatible elements (for example, 300-400 ppm Zr), well-fractionated rare earth element patterns ([La/Yb]N 18-21) and HIMU isotopic characters. They probably represent deep-sea, lateral, intrusive off-shoots from nearby seamounts of similar age. The olivine-plagioclase +/- clinopyroxene phyric tholeiitic pillow lavas and thin flows of Site 802 are nonvesicular and quench-textured throughout. Relative to normal-type mid-ocean ridge basalt, they are enriched in large-ion-lithophile elements, exhibit flat (unfractionated) rare earth element patterns and have distinctive (lower) Zr/Nb, Zr/Ta, La/Ta, and Hf/Th ratios. Overall they are compositionally and isotopically similar to the mid-Cretaceous tholeiites of the Nauru basin and the Ontong-Java and Manihiki plateaus. The Site 802 tholeiites differ from the thickened crustal segments of the oceanic plateaus, however, in apparently representing only a thin veneer over the local basement in an off-axis environment.

Geochemistry and oxygen and iron isotope ratios of mafic rocks

Recycling of oceanic crust into the deep mantle via subduction is a widely accepted mechanism for creating compositional heterogeneity in the upper mantle and for explaining the distinct geochemistry of mantle plumes. The oxygen isotope ratios (d18O) of some ocean island basalts (OIB) span values both above and below that of unmetasomatised upper mantle (5.5 ± 0.4 per mil) and provide support for this hypothesis, as it is widely assumed that most variations in d18O are produced by near-surface low-temperature processes. Here we show a significant linear relationship between d18O and stable iron isotope ratios (d57Fe) in a suite of pristine eclogite xenoliths. The d18O values of both bulk samples and garnets range from values within error of normal mantle to significantly lighter values. The observed range and correlation between d18O and d57Fe is unlikely to be inherited from oceanic crust, as d57Fe values determined for samples of hydrothermally altered oceanic crust do not differ significantly from the mantle value and show no correlation with d18O. It is proposed that the correlated d57Fe and d18O variations in this particular eclogite suite are predominantly related to isotopic fractionation by disequilibrium partial melting although modification by melt percolation processes cannot be ruled out. Fractionation of Fe and O isotopes by removal of partial melt enriched in isotopically heavy Fe and O is supported by negative correlations between bulk sample d57Fe and Cr content and bulk sample and garnet d18O and Sc contents, as Cr and Sc are elements that become enriched in garnet- and pyroxene-bearing melt residues. Melt extraction could take place either during subduction, where the eclogites represent the residues of melted oceanic lithosphere, or could take place during long-term residence within the lithospheric mantle, in which case the protoliths of the eclogites could be of either crustal or mantle origin. This modification of both d57Fe and d18O by melting processes and specifically the production of low-d18O signatures in mafic rocks implies that some of the isotopically light d18O values observed in OIB and eclogite xenoliths may not necessarily reflect near-surface processes or components.