364 research outputs found

    Water Allocation Under Distribution Losses: Comparing Alternative Institutions

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    The distribution of water resources is characterized by increasing returns to scale. Distribution systems link water generation to its end-use. Standard economic analysis overlooks the interaction among these micro-markets - generation, distribution and end-use. We compare water allocation when there is market power in each micro-market. These outcomes are compared with benchmark cases - social planning and a competitive business-as-usual regime. Simulations suggest that institutions with market power in generation and end-use generate significantly higher welfare than the distribution monopoly and the competitive regime. However, if the policy goal is to maximize the size of the grid, a distribution monopoly is preferred.infrastructure; market power; spatial models; vertical integration; water markets

    Optimal Mean Squared Error Imaging

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77345/1/AIAA-2002-4952-350.pd

    Post-menopausal alopecia due to ovarian hyperandrogenaemia treated with bilateral salpingo-oophorectomy

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    Introduction: Increased ovarian production of androgens due to the stimulation of luteinizing hormone (LH) on theca cells can cause hyperandrogenism that may present with signs of alopecia in postmenopausal women. Case description: A 65-year-old postmenopausal woman presented to the gynecology clinic with male-pattern baldness. Serum testosterone was high that was suppressed with gonadotropin-releasing hormone analog (GnRH agonist). This confirmed ovarian source of androgens. Laparoscopic salpingo-oophorectomy helped reduce androgen levels over a period of an year therefore reversing at least partially the hair loss. Conclusion: Gonadotropin-releasing hormone analogs can be useful to diagnose the source of increased androgen levels to be of ovarian origin. Once confirmed, laparoscopic bilateral salpingo-oophorectomy can reverse hair loss in these cases

    Highly Sensitive Detection of Staphylococcus aureus Directly from Patient Blood

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    Background: Rapid detection of bloodstream infections (BSIs) can be lifesaving. We investigated the sample processing and assay parameters necessary for highly-sensitive detection of bloodstream bacteria, using Staphylococcus aureus as a model pathogen and an automated fluidic sample processing – polymerase chain reaction (PCR) platform as a model diagnostic system. Methodology/Principal Findings: We compared a short 128 bp amplicon hemi-nested PCR and a relatively shorter 79 bp amplicon nested PCR targeting the S. aureus nuc and sodA genes, respectively. The sodA nested assay showed an enhanced limit of detection (LOD) of 5 genomic copies per reaction or 10 colony forming units (CFU) per ml blood over 50 copies per reaction or 50 CFU/ml for the nuc assay. To establish optimal extraction protocols, we investigated the relative abundance of the bacteria in different components of the blood (white blood cells (WBCs), plasma or whole blood), using the above assays. The blood samples were obtained from the patients who were culture positive for S. aureus. Whole blood resulted in maximum PCR positives with sodA assay (90 % positive) as opposed to cell-associated bacteria (in WBCs) (71 % samples positive) or free bacterial DNA in plasma (62.5 % samples positive). Both the assays were further tested for direct detection of S. aureus in patient whole blood samples that were contemporaneous culture positive. S. aureus was detected in 40/45 of culture-positive patients (sensitivity 89%, 95 % CI 0.75–0.96) and 0/59 negative controls with the sodA assay (specificit

    Cognitive Behavioral Therapy for Insomnia in Alcohol‐Dependent Veterans: A Randomized, Controlled Pilot Study

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149521/1/acer14030.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149521/2/acer14030-sup-0001-FigS1-S3.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149521/3/acer14030_am.pd

    Higher oxygen saturation with hydroxyurea in paediatric sickle cell disease.

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    INTRODUCTION: Sickle cell disease (SCD) is one of the most common inherited diseases worldwide. It is associated with lifelong morbidity and reduced life expectancy. Hydroxyurea (HU) has been shown to reduce the frequency and severity of vaso-occlusive episodes in SCD. Hypoxaemia and intermittent nocturnal oxygen desaturations occur frequently in children with SCD and contribute to the associated morbidity, including risk of cerebrovascular disease. OBJECTIVE: To evaluate the effect of HU on oxygen saturation (SpO2) overnight and on daytime SpO2 spot checks in children with SCD. METHODS: A retrospective review of children with SCD and respiratory problems who attended two UK tertiary sickle respiratory clinics and were treated with HU. Longitudinal data were collected from 2 years prior and up to 3 years after the commencement of HU. RESULTS: Forty-three children, 23 males (53%) with a median age of 9 (range 1.8-18) years were included. In the 21 children who had comparable sleep studies before and after starting HU, mean SpO2 was higher (95.2% from 93.5%, p=0.01) and nadir SpO2 was higher (87.2% from 84.3%, p=0.009) when taking HU. In 32 of the children, spot daytime oxygen saturations were also higher (96.3% from 93.5%, p=0.001). CONCLUSION: Children with SCD had higher oxygen saturation overnight and on daytime spot checks after starting HU. These data suggest HU may be helpful for treating persistent hypoxaemia in children with SCD pending more evidence from a randomised clinical trial

    Signaling Specificity Provided by the Arabidopsis thaliana Heterotrimeric G-Protein γ Subunits AGG1 and AGG2 Is Partially but Not Exclusively Provided through Transcriptional Regulation

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    The heterotrimeric G-protein complex in Arabidopsis thaliana consists of one α, one ß and three γ subunits. While two of the γ subunits, AGG1 and AGG2 have been shown to provide functional selectivity to the Gßγ dimer in Arabidopsis, it is unclear if such selectivity is embedded in their molecular structures or conferred by the different expression patterns observed in both subunits. In order to study the molecular basis for such selectivity we tested genetic complementation of AGG1- and AGG2 driven by the respectively swapped gene promoters. When expressed in the same tissues as AGG1, AGG2 rescues some agg1 mutant phenotypes such as the hypersensitivity to Fusarium oxysporum and D-mannitol as well as the altered levels of lateral roots, but does not rescue the early flowering phenotype. Similarly, AGG1 when expressed in the same tissues as AGG2 rescues the osmotic stress and lateral-root phenotypes observed in agg2 mutants but failed to rescue the heat-stress induction of flowering. The fact that AGG1 and AGG2 are functionally interchangeable in some pathways implies that, at least for those pathways, signaling specificity resides in the distinctive spatiotemporal expression patterns exhibited by each γ subunit. On the other hand, the lack of complementation for some phenotypes indicates that there are pathways in which signaling specificity is provided by differences in the primary AGG1 and AGG2 amino acid sequences

    Quantification of Silent Cerebral Infarction on High-Resolution FLAIR and Cognition in Sickle Cell Anemia

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    Research in sickle cell anemia (SCA) has used, with limited race-matched control data, binary categorization of patients according to the presence or absence of silent cerebral infarction (SCI). SCI have primarily been identified using low-resolution MRI, with radiological definitions varying in lesion length and the requirement for abnormality on both fluid attenuated inversion recovery (FLAIR) and T1-weighted images. We aimed to assess the effect of published SCI definitions on global, regional, and lobar lesion metrics and their value in predicting cognition. One hundred and six patients with SCA and 48 controls aged 8-30 years underwent 3T MRI with a high-resolution FLAIR sequence and Wechsler cognitive assessment. Prevalence, number, and volume of lesions were calculated using a semi-automated pipeline for SCI defined as: (1) Liberal: any length (L-SCI); (2) Traditional: >3 mm in greatest dimension (T-SCI); (3) Restrictive; >3 mm in greatest dimension with a corresponding T1-weighted hypo-intensity (R-SCI). Globally, as hypothesized, there were large effects of SCI definition on lesion metrics in patients and controls, with prevalence varying from 24-42% in patients, and 4-23% in controls. However, contrary to hypotheses, there was no effect of any global metric on cognition. Regionally, there was a consistent distribution of SCI in frontal and parietal deep and juxta-cortical regions across definitions and metrics in patients, but no consistent distribution in controls. Effects of regional SCI metrics on cognitive performance were of small magnitude; some were paradoxical. These findings expose the challenges associated with the widespread use of SCI presence as a biomarker of white-matter injury and cognitive dysfunction in cross-sectional high-resolution MRI studies in patients with SCA. The findings indicate that with high-resolution MRI: (1) radiological definitions have a large effect on resulting lesion groups, numbers, and volumes; (2) there is a non-negligible prevalence of lesions in young healthy controls; and (3) at the group-level, there is no cross-sectional association between global lesion metrics and general cognitive impairment irrespective of lesion definition and metric. With high-resolution multi-modal MRI, the dichotomy of presence or absence of SCI does not appear to be a sensitive biomarker for the detection of functionally significant pathology; the search for appropriate endpoints for clinical treatment trials should continue
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