355 research outputs found

    Utility-Scale Concentrating Solar Power and Photovoltaic Projects: A Technology and Market Overview

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    Over the last several years, solar energy technologies have been, or are in the process of being, deployed at unprecedented levels. A critical recent development, resulting from the massive scale of projects in progress or recently completed, is having the power sold directly to electric utilities. Such 'utility-scale' systems offer the opportunity to deploy solar technologies far faster than the traditional 'behind-the-meter' projects designed to offset retail load. Moreover, these systems have employed significant economies of scale during construction and operation, attracting financial capital, which in turn can reduce the delivered cost of power. This report is a summary of the current U.S. utility-scale solar state-of-the-market and development pipeline. Utility-scale solar energy systems are generally categorized as one of two basic designs: concentrating solar power (CSP) and photovoltaic (PV). CSP systems can be further delineated into four commercially available technologies: parabolic trough, central receiver (CR), parabolic dish, and linear Fresnel reflector. CSP systems can also be categorized as hybrid, which combine a solar-based system (generally parabolic trough, CR, or linear Fresnel) and a fossil fuel energy system to produce electric power or steam

    Potential of Securitization in Solar PV Finance

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    This report aims to demonstrate, hypothetically and at a high level, what volumes of solar deployment could be supported given solar industry access to the capital markets in the form of security issuance. Securitization is not anticipated to replace tax equity in the near- to mid-term, but it could provide an additional source of funds that would be comparatively inexpensive and could reduce the weighted average cost of capital for a given solar project or portfolio. Thus, the potential to securitize solar assets and seek financing in the capital markets could help to sustain the solar industry when the investment tax credit (ITC) -- one of the federal incentives that has leveraged billions of dollars of private capital in the solar industry -- drops from 30% to 10% at the close of 2016. The report offers analysis on the size of the U.S. third-party financed solar market, as well as on the volumes (in MW) of solar asset origination possible through a $100 million securitization fund (assuming no overcollateralization). It also provides data on the size of the relevant securities markets and how the solar asset class may fit into these markets

    Renewable Energy Finance Tracking Initiative (REFTI): Snapshot of Recent Geothermal Financing Terms, Fourth Quarter 2009 - Second Half 2011

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    This report is a review of geothermal project financial terms as reported in the National Renewable Energy Laboratory's Renewable Energy Finance Tracking Initiative (REFTI). The data were collected over seven analysis periods from the fourth quarter (Q4) of 2009 to the second half (2H) of 2011

    Myofascial urinary frequency syndrome is a novel syndrome of bothersome lower urinary tract symptoms associated with myofascial pelvic floor dysfunction

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    This study describes a novel, distinct phenotype of urinary symptoms named myofascial urinary frequency syndrome (MUFS) present in one-third of individuals presenting with urinary frequency. In addition to a characteristic symptom constellation suggestive of myofascial dysfunction, MUFS subjects exhibit persistency : a persistent feeling of needing to urinate regardless of urine volume. On examination, 97% of MUFS patients demonstrated pelvic floor hypertonicity with either global tenderness or myofascial trigger points, and 92% displayed evidence of impaired muscular relaxation, hallmarks of myofascial dysfunction. To confirm this symptom pattern was attributable to the pelvic floor musculature, we confirmed the presence of persistency in 68 patients with pelvic floor myofascial dysfunction established through comprehensive examination and electromyography and corroborated by improvement with pelvic floor myofascial release. These symptoms distinguish subjects with myofascial dysfunction from subjects with OAB, IC/BPS, and asymptomatic controls, confirming MUFS is a distinct LUTS symptom complex

    Model-Independent Comparison of Direct vs. Indirect Detection of Supersymmetric Dark Matter

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    We compare the rate for elastic scattering of neutralinos from various nuclei with the flux of upward muons induced by energetic neutrinos from neutralino annihilation in the Sun and Earth. We consider both scalar and axial-vector interactions of neutralinos with nuclei. We find that the event rate in a kg of germanium is roughly equivalent to that in a 10510^5- to 10710^7-m2^2 muon detector for a neutralino with primarily scalar coupling to nuclei. For an axially coupled neutralino, the event rate in a 50-gram hydrogen detector is roughly the same as that in a 10- to 500-m2^2 muon detector. Expected experimental backgrounds favor forthcoming elastic-scattering detectors for scalar couplings while the neutrino detectors have the advantage for axial-vector couplings.Comment: 10 pages, self-unpacking uuencoded PostScript fil

    The Persistency Index: A novel screening tool for identifying myofascial pelvic floor dysfunction in patients seeking care for lower urinary tract symptoms

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    BACKGROUND: Patients with myofascial pelvic floor dysfunction often present with lower urinary tract symptoms, such as urinary frequency, urgency, and bladder pressure. Often confused with other lower urinary tract disorders, this constellation of symptoms, recently termed myofascial urinary frequency syndrome, is distinct from other lower urinary tract symptoms and optimally responds to pelvic floor physical therapy. A detailed pelvic floor myofascial examination performed by a skilled provider is currently the only method to identify myofascial urinary frequency syndrome. Despite a high influence on quality of life, low awareness of this condition combined with no objective diagnostic testing leads to the frequent misdiagnosis or underdiagnosis of myofascial urinary frequency syndrome. OBJECTIVE: This study aimed to develop a screening measure to identify patients with myofascial urinary frequency syndrome (bothersome lower urinary tract symptoms secondary to myofascial pelvic floor dysfunction) from patient-reported symptoms. STUDY DESIGN: A population of patients with isolated myofascial urinary frequency syndrome was identified by provider diagnosis from a tertiary urology practice and verified by standardized pelvic floor myofascial examination and perineal surface pelvic floor electromyography. Least Angle Shrinkage and Selection Operator was used to identify candidate features from the Overactive Bladder Questionnaire, Female Genitourinary Pain Index, and Pelvic Floor Distress Index predictive of myofascial urinary frequency syndrome in a pooled population also containing subjects with overactive bladder (n=42), interstitial cystitis/bladder pain syndrome (n=51), and asymptomatic controls (n=54) (derivation cohort). A simple, summated score of the most discriminatory questions using the original scaling of the Pelvic Floor Distress Index 5 (0-4) and Genitourinary Pain Index 5 (0-5) and modified scaling of Female Genitourinary Pain Index 2b (0-3) had an area under the curve of 0.75. As myofascial urinary frequency syndrome was more prevalent in younger subjects, the inclusion of an age penalty (3 points added if under the age of 50 years) improved the area under the curve to 0.8. This score was defined as the Persistency Index (possible score of 0-15). The Youden Index was used to identify the optimal cut point Persistency Index score for maximizing sensitivity and specificity. RESULTS: Using a development cohort of 215 subjects, the severity (Pelvic Floor Distress Index 5) and persistent nature (Female Genitourinary Pain Index 5) of the sensation of incomplete bladder emptying and dyspareunia (Female Genitourinary Pain Index 2b) were the most discriminatory characteristics of the myofascial urinary frequency syndrome group, which were combined with age to create the Persistency Index. The Persistency Index performed well in a validation cohort of 719 patients with various lower urinary tract symptoms, including overactive bladder (n=285), interstitial cystitis/bladder pain syndrome (n=53), myofascial urinary frequency syndrome (n=111), controls (n=209), and unknown diagnoses (n=61), exhibiting an area under the curve of 0.74. A Persistency Index score ≥7 accurately identified patients with myofascial urinary frequency syndrome from an unselected population of individuals with lower urinary tract symptoms with 80% sensitivity and 61% specificity. A combination of the Persistency Index with the previously defined Bladder Pain Composite Index and Urge Incontinence Composite Index separated a population of women seeking care for lower urinary tract symptoms into groups consistent with overactive bladder, interstitial cystitis/bladder pain syndrome, and myofascial urinary frequency syndrome phenotypes with an overall diagnostic accuracy of 82%. CONCLUSION: Our study recommends a novel screening method for patients presenting with lower urinary tract symptoms to identify patients with myofascial urinary frequency syndrome. As telemedicine becomes more common, this index provides a way of screening for myofascial urinary frequency syndrome and initiating pelvic floor physical therapy even before a confirmatory pelvic examination

    A novel research definition of bladder health in women and girls: Implications for research and public health promotion

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    BACKGROUND:Bladder health in women and girls is poorly understood, in part, due to absence of a definition for clinical or research purposes. This article describes the process used by a National Institutes of Health funded transdisciplinary research team (The Prevention of Lower Urinary Tract Symptoms [PLUS] Consortium) to develop a definition of bladder health. METHODS:The PLUS Consortium identified currently accepted lower urinary tract symptoms (LUTS) and outlined elements of storage and emptying functions of the bladder. Consistent with the World Health Organization's definition of health, PLUS concluded that absence of LUTS was insufficient and emphasizes the bladder's ability to adapt to short-term physical, psychosocial, and environmental challenges for the final definition. Definitions for subjective experiences and objective measures of bladder dysfunction and health were drafted. An additional bioregulatory function to protect against infection, neoplasia, chemical, or biologic threats was proposed. RESULTS:PLUS proposes that bladder health be defined as: "A complete state of physical, mental, and social well-being related to bladder function and not merely the absence of LUTS. Healthy bladder function permits daily activities, adapts to short-term physical or environmental stressors, and allows optimal well-being (e.g., travel, exercise, social, occupational, or other activities)." Definitions for each element of bladder function are reported with suggested subjective and objective measures. CONCLUSIONS:PLUS used a comprehensive transdisciplinary process to develop a bladder health definition. This will inform instrument development for evaluation of bladder health promotion and prevention of LUTS in research and public health initiatives

    Indirect Detection of a Light Higgsino Motivated by Collider Data

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    Kane and Wells recently argued that collider data point to a Higgsino-like lightest supersymmetric partner which would explain the dark matter in our Galactic halo. They discuss direct detection of such dark-matter particles in laboratory detectors. Here, we argue that such a particle, if it is indeed the dark matter, might alternatively be accessible in experiments which search for energetic neutrinos from dark-matter annihilation in the Sun. We provide accurate analytic estimates for the rates which take into account all relevant physical effects. Currently, the predicted signal falls roughly one to three orders of magnitude below experimental bounds, depending on the mass and coupling of the particle; however, detectors such as MACRO, super-Kamiokande, and AMANDA will continue to take data and should be able to rule out or confirm an interesting portion of the possible mass range for such a dark-matter particle within the next five years.Comment: 10 pages, RevTe

    Optical Properties of Deep Ice at the South Pole - Absorption

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    We discuss recent measurements of the wavelength-dependent absorption coefficients in deep South Pole ice. The method uses transit time distributions of pulses from a variable-frequency laser sent between emitters and receivers embedded in the ice. At depths of 800 to 1000 m scattering is dominated by residual air bubbles, whereas absorption occurs both in ice itself and in insoluble impurities. The absorption coefficient increases approximately exponentially with wavelength in the measured interval 410 to 610 nm. At the shortest wavelength our value is about a factor 20 below previous values obtained for laboratory ice and lake ice; with increasing wavelength the discrepancy with previous measurements decreases. At around 415 to 500 nm the experimental uncertainties are small enough for us to resolve an extrinsic contribution to absorption in ice: submicron dust particles contribute by an amount that increases with depth and corresponds well with the expected increase seen near the Last Glacial Maximum in Vostok and Dome C ice cores. The laser pulse method allows remote mapping of gross structure in dust concentration as a function of depth in glacial ice.Comment: 26 pages, LaTex, Accepted for publication in Applied Optics. 9 figures, not included, available on request from [email protected]
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