947 research outputs found

    The poem will resemble you: A human-computer collaboration

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    Senior Project submitted to The Division of Languages and Literature of Bard College

    Exploring challenging variations of parsons problems

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    Introductory programming classes teach students to program using worked examples, code tracing, and code writing exercises. Parsons Problems are an educational innovation in which students unscramble provided lines of code, as a step towards bridging the gap between reading and writing code. Though Parsons Problems have been found effective, there is some evidence that students can use syntactic heuristics to help them solve these problems without fully understanding the solution. To address this limitation, we introduce Faded Parsons Problems, a variation of Parsons Problems where parts of the provided code are incomplete. We explore a specific instantiation of this idea, Blank-Variable Parsons Problems, in which all variable names are blanked out. Unlike another Parsons Problem variation-adding distractor code lines-Blank-Variable Parsons can be automatically created from a solution without additional effort from an instructor. A 75 minute pilot study with CS1 students indicates that solving standard Parsons Problems does not lead to short-term near-transfer in code writing, suggesting a need for problems with less scaffolding. Additionally, students self-report Blank-Variable Parsons as fitting in difficulty between Parsons Problems and code writing, suggesting Blank-Variable Parsons may be one opportunity to fill this gap

    Quantifying Geomorphic Controls on Time in Weathering Systems

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    AbstractThe time minerals spend in the weathering zone is crucial in determining soil biogeochemical cycles, solid state chemistry and soil texture. This length of time is closely related to erosion rates and can be modulated by sediment transport, mixing rates within the soil and the temporal evolution of erosion. Here we describe how time length can be approximated using geomorphic metrics and how topography reveals changing residence times of minerals within soils. We also show model simulations from a field site in California that can reproduce observed solid state geochemistry in the eroding portion of the landscape

    Potential of high-resolution detection and retrieval of precipitation fields from X-band spaceborne synthetic aperture radar over land

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    Abstract. X-band Synthetic Aperture Radars (X-SARs), able to image the Earth's surface at metric resolution, may provide a unique opportunity to measure rainfall over land with spatial resolution of about few hundred meters, due to the atmospheric moving-target degradation effects. This capability has become very appealing due to the recent launch of several X-SAR satellites, even though several remote sensing issues are still open. This work is devoted to: (i) explore the potential of X-band high-resolution detection and retrieval of rainfall fields from space using X-SAR signal backscattering amplitude and interferometric phase; (ii) evaluate the effects of spatial resolution degradation by precipitation and inhomogeneous beam filling when comparing to other satellite-based sensors. Our X-SAR analysis of precipitation effects has been carried out using both a TerraSAR-X (TSX) case study of Hurricane "Gustav" in 2008 over Mississippi (USA) and a COSMO-SkyMed (CSK) X-SAR case study of orographic rainfall over Central Italy in 2009. For the TSX case study the near-surface rain rate has been retrieved from the normalized radar cross section by means of a modified regression empirical algorithm (MREA). A relatively simple method to account for the geometric effect of X-SAR observation on estimated rainfall rate and first-order volumetric effects has been developed and applied. The TSX-retrieved rain fields have been compared to those estimated from the Next Generation Weather Radar (NEXRAD) in Mobile (AL, USA). The rainfall detection capability of X-SAR has been tested on the CSK case study using the repeat-pass coherence response and qualitatively comparing its signature with ground-based Mt. Midia C-band radar in central Italy. A numerical simulator to represent the effect of the spatial resolution and the antenna pattern of TRMM satellite Precipitation Radar (PR) and Microwave Imager (TMI), using high-resolution TSX-retrieved rain images, has been also set up in order to evaluate the rainfall beam filling phenomenon. As expected, the spatial average can modify the statistics of the high-resolution precipitation fields, strongly reducing its dynamics in a way non-linearly dependent on the rain rate local average value

    Proteasome Activation by Hepatitis C Core Protein Is Reversed by Ethanol-Induced Oxidative Stress

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    Background & Aims: The proteasome is a major cellular proteinase. Its activity is modulated by cellular oxidants. Hepatitis C core protein and ethanol exposure both cause enhanced oxidant generation. The aim was to investigate whether core protein, by its ability to generate oxidants, alters proteasome activity and whether these alterations are further affected by ethanol exposure. Methods: These interactions were examined in Huh-7 cell lines that expressed inducible HCV core protein and/or constitutive cytochrome P450 2E1 (CYP2E1) and as purified components in a cell-free system. Chymotrypsin-like proteasome activity was measured fluorometrically. Results: Proteasome activity in core-positive 191-20 cells was 20% higher than that in core-negative cells and was enhanced 3-fold in CYP2E1-expressing L14 cells. Exposure of core-positive cells to glutathione ethyl ester, catalase, or the CYP2E1 inhibitor diallyl sulfide partially reversed the elevation of proteasome activity in core-positive cells, whereas ethanol exposure suppressed proteasome activity. The results indicate that proteasome activity was up-regulated by low levels of core-induced oxidative stress but downregulated by high levels of ethanol-elicited stress. These findings were partially mimicked in a cell-free system. Addition of core protein enhanced the peptidase activity of purified 20S proteasome containing the proteasome activator PA28 and was further potentiated by addition of liver mitochondrial and/or microsome fractions. However, proteasome activation was significantly attenuated when fractions were obtained from ethanol-fed animals. Conclusions: HCV core protein interacts with PA28, mitochondrial, and endoplasmic reticulum proteins to cause low levels of oxidant stress and proteasome activation, which is dampened during ethanol metabolism when oxidant generation is higher

    Potential of High-resolution Detection and Retrieval of Precipitation Fields from X-band Spaceborne Synthetic Aperture Radar over land

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    X-band Synthetic Aperture Radars (X-SARs), able to image the Earth’s surface at metric resolution, may provide a unique opportunity to measure rainfall over land with spatial resolution of about few hundred meters, due to the atmospheric moving-target degradation effects. This capability has become very appealing due to the recent launch of several X-SAR satellites, even though several remote sensing issues are still open. This work is devoted to: (i) explore the potential of X-band high-resolution detection and retrieval of rainfall fields from space using X-SAR signal backscattering amplitude and interferometric phase; (ii) evaluate the effects of spatial resolution degradation by precipitation and inhomogeneous beam filling when comparing to other satellite-based sensors. Our X-SAR analysis of precipitation effects has been carried out using both a TerraSAR-X (TSX) case study of Hurricane “Gustav” in 2008 over Mississippi (USA) and a COSMO-SkyMed (CSK) X-SAR case study of orographic rainfall over Central Italy in 2009. For the TSX case study the near-surface rain rate has been retrieved from the normalized radar cross section by means of a modified regression empirical algorithm (MREA). A relatively simple method to account for the geometric effect of X-SAR observation on estimated rainfall rate and firstorder volumetric effects has been developed and applied. The TSX-retrieved rain fields have been compared to those estimated from the Next Generation Weather Radar (NEXRAD) in Mobile (AL, USA). The rainfall detection capability of X-SAR has been tested on the CSK case study using the Correspondence to: F. S. Marzano ([email protected]) repeat-pass coherence response and qualitatively comparing its signature with ground-based Mt. Midia C-band radar in central Italy. A numerical simulator to represent the effect of the spatial resolution and the antenna pattern of TRMMsatellite Precipitation Radar (PR) and Microwave Imager (TMI), using high-resolution TSX-retrieved rain images, has been also set up in order to evaluate the rainfall beam filling phenomenon. As expected, the spatial average can modify the statistics of the high-resolution precipitation fields, strongly reducing its dynamics in a way non-linearly dependent on the rain rate local average value

    A pilot case series of a brief acceptance and commitment therapy (ACT)-based guided self-help intervention for improving quality of life and mood in muscle disorders

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    This study aimed to demonstrate proof of concept and acceptability of a brief acceptance and commitment therapy (ACT)-based guided self-help intervention for improving quality of life (QoL) and mood for people with muscle disorders (MD). A case-series with an AB design was used to assess changes in primary (QoL) and secondary (depression and anxiety) outcome variables across the period of study. Change in the psychological process targeted by ACT – psychological flexibility – was also investigated, to allow insight into possible treatment mechanisms. Post-intervention, participants also completed a brief free-text evaluation. Relative to pre-intervention scores, four (of seven) participants showed varying degrees of improvement in all primary and secondary outcome variables and were thus considered responders. However, consistent concomitant improvements in psychological flexibility were not apparent. Participants reported a mostly positive experience of the intervention; all appeared to complete the intervention, and no adverse events were reported. Nonetheless, there was evidence that those with compromised concentration or who report good initial QoL and low levels of distress may derive less benefit. Although several methodological weaknesses limit the strength of our conclusions, this ACT-based guided self-help intervention shows encouraging utility for improving QoL and mood in MD

    Chest computed tomography findings in HIV-infected individuals in the era of antiretroviral therapy

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    Background: Chest radiographic abnormalities were common in HIV-infected individuals in the pre-combination antiretroviral therapy era, but findings may differ now due to a changing spectrum of pulmonary complications. Copyright
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