152 research outputs found

    Mapping solar array location, size, and capacity using deep learning and overhead imagery

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    The effective integration of distributed solar photovoltaic (PV) arrays into existing power grids will require access to high quality data; the location, power capacity, and energy generation of individual solar PV installations. Unfortunately, existing methods for obtaining this data are limited in their spatial resolution and completeness. We propose a general framework for accurately and cheaply mapping individual PV arrays, and their capacities, over large geographic areas. At the core of this approach is a deep learning algorithm called SolarMapper - which we make publicly available - that can automatically map PV arrays in high resolution overhead imagery. We estimate the performance of SolarMapper on a large dataset of overhead imagery across three US cities in California. We also describe a procedure for deploying SolarMapper to new geographic regions, so that it can be utilized by others. We demonstrate the effectiveness of the proposed deployment procedure by using it to map solar arrays across the entire US state of Connecticut (CT). Using these results, we demonstrate that we achieve highly accurate estimates of total installed PV capacity within each of CT's 168 municipal regions

    Media Use for Professional Information Among German Dentists

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    OBJECTIVES: The purpose of the study was to assess the media use for professional information among German dentists on the basis of a representative survey. METHODS: After questionnaire development and pretests, 3000 questionnaires were mailed to German dentists in early October 2000. The random sample was taken by systematic sampling from the database of the German Federal Dentists Chamber. The survey wasannounced in a German Dental Journal (Zahn‰rztliche Mitteilungen). RESULTS: The return rate amounted to 28.9% (n=866). Among the questioned dentists, 39.7% had an Internet access in their workplace / practice, 61.4% a private access at home. 46% used the Internet not at all as a source of information. 21.3% for up to an hour a week and 10.2% for more than an hour a week. The importance of the Internet as a source of information is given as high by 30.5% of respondents, 49.1% said its importance was average and 15.3% saw it as low, 5.1% didn\u27t answer this question. The preference for mediation of scientific information were given as shown in the table below (percentage of high importance): Journal-supplements 74%, Mail 63%, Advanced education 55%, Internet 40%, E-mail 33%, Modules in the practice software 20%. CONCLUSION: With a rather low return-rate, this study has only an explorative character. Although a high availability of the Internet in the private area was present, the possibilities of electronic procurement of information were used only cautiously. For the supply of overview works or statements, conventional means such as the post or publication in journals are preferred over electronic media. This study was supported by the German Society of Dentistry and Oral Medicine

    A Two-level Prediction Model for Deep Reactive Ion Etch (DRIE)

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    We contribute a quantitative and systematic model to capture etch non-uniformity in deep reactive ion etch of microelectromechanical systems (MEMS) devices. Deep reactive ion etch is commonly used in MEMS fabrication where high-aspect ratio features are to be produced in silicon. It is typical for many supposedly identical devices, perhaps of diameter 10 mm, to be etched simultaneously into one silicon wafer of diameter 150 mm. Etch non-uniformity depends on uneven distributions of ion and neutral species at the wafer level, and on local consumption of those species at the device, or die, level. An ion–neutral synergism model is constructed from data obtained from etching several layouts of differing pattern opening densities. Such a model is used to predict wafer-level variation with an r.m.s. error below 3%. This model is combined with a die-level model, which we have reported previously, on a MEMS layout. The two-level model is shown to enable prediction of both within-die and wafer-scale etch rate variation for arbitrary wafer loadings.Singapore-MIT Alliance (SMA

    Sensitivity of the Southern Ocean to enhanced regional Antarctic ice sheet meltwater input

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    Despite advances in our understanding of the processes driving contemporary sea level rise, the stability of the Antarctic ice sheets and their contribution to sea level under projected future warming remains uncertain due to the influence of strong ice-climate feedbacks. Disentangling these feedbacks is key to reducing uncertainty. Here we present a series of climate system model simulations that explore the potential effects of increased West Antarctic Ice Sheet (WAIS) meltwater flux on Southern Ocean dynamics. We project future changes driven by sectors of the WAIS, delivering spatially and temporally variable meltwater flux into the Amundsen, Ross and Weddell embayments over future centuries. Focusing on the Amundsen Sea sector of the WAIS over the next 200 years, we demonstrate that the enhanced meltwater flux rapidly stratifies surface waters, resulting in a significant decrease in the rate of Antarctic Bottom Water (AABW) formation. This triggers rapid pervasive ocean warming (>1°C) at depth due to advection from the original site(s) of meltwater input. The greatest warming predicted along sectors of the ice sheet that are highly sensitized to ocean forcing, creating a feedback loop that could enhance basal ice shelf melting and grounding line retreat. Given that we do not include the effects of rising CO2 - predicted to further reduce AABW formation - our experiments highlight the urgent need to develop a new generation of fully-coupled ice sheet climate models, that include feedback mechanisms such as this, to reduce uncertainty in climate and sea level projections

    Climatic and glacial impact on erosion patterns and sediment provenance in the Himalayan rain shadow, Zanskar River, NW India

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    Erosion is a key step in the destruction and recycling of the continental crust yet its primary drivers continue to be debated. The relative balance between climatic and solid Earth forces in determining erosion patterns and rates, and in turn orogenic architecture, is unresolved. The monsoon-dominated frontal Himalaya is a classic example of how surface processes may drive focused denudation and potentially control structural evolution. We investigate whether there is a clear relationship between climate and erosion in the drier Himalayan rain shadow of northwest India where a coupled climate-erosion relationship is less clear. We present a new integrated dataset combining bulk petrography, geomorphometric analysis, detrital U-Pb zircon geochronology, and bulk Nd and Sr isotope geochemistry from modern river sediments that provides constraints on spatial patterns of sediment production and transport in the Zanskar River. Zanskar River sands are dominated by Greater Himalayan detritus sourced from the glaciated Stod River catchment that represents only 13% of the total basin area. Prevalent zircon peaks from the Cambro-Ordovician (440–500 Ma) and Mississippian-Permian (245–380 Ma) indicate more abundant pre-Himalayan granitoids in the northwest Himalaya than in the central and eastern Himalaya. Erosion from the widely-exposed Tethyan Himalaya, however, appears modest. Spatial patterns of erosion do not correlate with highest channel steepness. Our data demonstrate that Zanskar differs from the monsoon-soaked frontal Himalaya and the arid, extremely slow-eroding orogenic interior in that focused erosion and sediment production are driven by glaciers. Subsequent remobilization of glacially-derived sediments is likely controlled by monsoonal rainfall and we suggest sediment reworking plays an important role. These data support strong climatic control on modern orogenic erosion on the periphery of the Himalayan rain shadow

    Haemoglobin mass and running time trial performance after recombinant human erythropoietin administration in trained men

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    <p>Recombinant human erythropoietin (rHuEpo) increases haemoglobin mass (Hbmass) and maximal oxygen uptake (vË™ O2 max).</p> <p>Purpose: This study defined the time course of changes in Hbmass, vË™ O2 max as well as running time trial performance following 4 weeks of rHuEpo administration to determine whether the laboratory observations would translate into actual improvements in running performance in the field.</p> <p>Methods: 19 trained men received rHuEpo injections of 50 IUNkg21 body mass every two days for 4 weeks. Hbmass was determined weekly using the optimized carbon monoxide rebreathing method until 4 weeks after administration. vË™ O2 max and 3,000 m time trial performance were measured pre, post administration and at the end of the study.</p> <p>Results: Relative to baseline, running performance significantly improved by ,6% after administration (10:3061:07 min:sec vs. 11:0861:15 min:sec, p,0.001) and remained significantly enhanced by ,3% 4 weeks after administration (10:4661:13 min:sec, p,0.001), while vË™ O2 max was also significantly increased post administration (60.765.8 mLNmin21Nkg21 vs. 56.066.2 mLNmin21Nkg21, p,0.001) and remained significantly increased 4 weeks after rHuEpo (58.065.6 mLNmin21Nkg21, p = 0.021). Hbmass was significantly increased at the end of administration compared to baseline (15.261.5 gNkg21 vs. 12.761.2 gNkg21, p,0.001). The rate of decrease in Hbmass toward baseline values post rHuEpo was similar to that of the increase during administration (20.53 gNkg21Nwk21, 95% confidence interval (CI) (20.68, 20.38) vs. 0.54 gNkg21Nwk21, CI (0.46, 0.63)) but Hbmass was still significantly elevated 4 weeks after administration compared to baseline (13.761.1 gNkg21, p<0.001).</p> <p>Conclusion: Running performance was improved following 4 weeks of rHuEpo and remained elevated 4 weeks after administration compared to baseline. These field performance effects coincided with rHuEpo-induced elevated vË™ O2 max and Hbmass.</p&gt

    Controls on erosion in the western Tarim Basin: implications for the uplift of northwest Tibet and the Pamir

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    We present here bulk sediment major element chemistry, Nd and Sr isotope ratios, and detrital apatite fission-track (AFT) and U-Pb zircon ages to characterize the provenance of the southwestern Taklimakan Desert (northwest China) and the three major rivers draining this region. We establish the spatial and temporal controls on erosion and sediment transport in the modern Tibetan rain shadow. The Hotan River drains the North Kunlun block and is characterized by zircon populations at 160–230 Ma and 370–520 Ma. The Yarkand River shares these grains with the Hotan, but also has a very prominent zircon population at 40–160 Ma, which is common in Karakoram basement, indicating heavy sediment flux from these ranges to that drainage. This implies a strong control on erosion by topographic steepness and precipitation mediated through glaciation. Our zircon data confirm earlier studies that indicated that the Taklimakan sand is derived from both the Kunlun and Pamir Mountains. AFT ages are younger in the Hotan River than in the Kashgar River, which drains the Pamir, and in both are younger than in the Transhimalaya and parts of the western edge of the Tibetan Plateau. Exhumation is estimated at ~1000 m/m.y in the North Kunlun and ~500 m/m.y. in the eastern Pamir, which have been exhuming more slowly than the western ranges in the recent past. Holocene aggradation terracing was dated using quartz optically stimulated luminescence methods and is mostly associated with times of fluctuating climate after 4 ka, with phases of valley filling dated at 2.6, 1.4, and 0.4 ka. The heights and volumes of the terraces show that sediment storage in the mountains is not a significant buffer to sediment transport, in contrast to the more monsoonal Indus system directly to the south. South of the Mazatag Ridge a significant eolian deposit accumulated ~500 yr ago, but this has been deflated in more recent times. Comparison of the modern river data with those previously measured from Cenozoic foreland sedimentary rocks shows that no sediment similar to that of the modern Yarkand River is seen in the geologic record, which is inferred to be younger than 11 Ma, and probably much less. Uplift of the North Kunlun had started by ca. 17 Ma, somewhat after that of the Pamir and Songpan Garze of northwestern Tibet, dated to before 24 Ma. Sediment from the Kunlun reached the foreland basin between 14 and 11 Ma. North Kunlun exhumation accelerated before 3.7 Ma, likely linked to faster rock uplift

    Computer-Assisted Prototyping of Advanced Microsystems

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    Contains reports on five research projects.Defense Advanced Research Projects Agency Contract DABT 63-95-C-0088Stanford Universit

    Isothiocyanates induce oxidative stress and suppress the metastasis potential of human non-small cell lung cancer cells

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    <p>Abstract</p> <p>Background</p> <p>Isothiocyanates are natural compounds found in consumable cruciferous vegetables. They have been shown to inhibit chemical carcinogenesis by a wide variety of chemical carcinogens in animal models. Recent studies have also shown that isothiocyanates have antitumor activity, inhibiting the growth of several types of cultured human cancer cells. Our previous study showed that PEITC inhibited human leukemia cells growth by inducing apoptosis. However, the effect of isothiocyanates on lung cancer cell metastasis has not been studied. In the present study, we investigated the inhibitory effects of BITC and PEITC on metastatic potential of highly metastatic human lung cancer L9981 cells.</p> <p>Methods</p> <p>Cell migration and invasion were measured by wound healing assay and transwell chemotaxis assay. Expression of metastasis-related genes was assessed by quantitative RT-PCR and Western blotting. The mechanisms of action were evaluated by flow cytometry, reporter assay and Western blotting.</p> <p>Results</p> <p>Our data showed that both BITC and PEITC inhibited L9981 cell growth in a dose-dependent manner, the IC50 values were 5.0 and 9.7 μM, respectively. Cell migrations were reduced to 8.1% and 16.5% of control, respectively; and cell invasions were reduced to 2.7% and 7.3% of control, respectively. Metastasis-related genes MMP-2, Twist and β-catenin were also modulated. BITC and PEITC inhibited cell survival signaling molecules Akt and NFκB activation. Moreover, BITC and PEITC increased ROS generation and caused GSH depletion. Pretreatment with NAC blocked BITC and PEITC induced ROS elevation and NFκB inhibition.</p> <p>Conclusion</p> <p>Our results indicated that BITC and PEITC suppress lung cancer cell metastasis potential by modulation of metastasis-related gene expression, inhibition of Akt/NFκB pathway. Induction of oxidative stress may play an important role.</p
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