scispace - formally typeset
Search or ask a question

Showing papers by "University of Nevada, Reno published in 2009"


Proceedings ArticleDOI
20 Jun 2009
TL;DR: A novel method to detect and localize abnormal behaviors in crowd videos using Social Force model and it is shown that the social force approach outperforms similar approaches based on pure optical flow.
Abstract: In this paper we introduce a novel method to detect and localize abnormal behaviors in crowd videos using Social Force model. For this purpose, a grid of particles is placed over the image and it is advected with the space-time average of optical flow. By treating the moving particles as individuals, their interaction forces are estimated using social force model. The interaction force is then mapped into the image plane to obtain Force Flow for every pixel in every frame. Randomly selected spatio-temporal volumes of Force Flow are used to model the normal behavior of the crowd. We classify frames as normal and abnormal by using a bag of words approach. The regions of anomalies in the abnormal frames are localized using interaction forces. The experiments are conducted on a publicly available dataset from University of Minnesota for escape panic scenarios and a challenging dataset of crowd videos taken from the web. The experiments show that the proposed method captures the dynamics of the crowd behavior successfully. In addition, we have shown that the social force approach outperforms similar approaches based on pure optical flow.

1,585 citations


Journal ArticleDOI
TL;DR: A rapid systemic signal in Arabidopsis thaliana was reported that traveled at a rate of 8.4 centimeters per minute and was dependent on the respiratory burst oxidase homolog D (RbohD) gene, which encodes a plant NADPH oxidase that generates reactive oxygen species.
Abstract: Cell-to-cell communication and long-distance signaling play a key role in the response of plants to pests, mechanical wounding, and extreme environmental conditions Here, we report on a rapid systemic signal in Arabidopsis thaliana that traveled at a rate of 84 centimeters per minute and was dependent on the respiratory burst oxidase homolog D (RbohD) gene Signal propagation was accompanied by the accumulation of reactive oxygen species (ROS) in the extracellular spaces between cells and was inhibited by the suppression of ROS accumulation at locations distant from the initiation site The rapid systemic signal was triggered by wounding, heat, cold, high-intensity light, and salinity stresses Our results reveal the profound role that ROS play in mediating rapid, long-distance, cell-to-cell propagating signals in plants

923 citations


Journal ArticleDOI
TL;DR: In this paper, a novel osmotic membrane bioreactor (OsMBR) is presented, which utilizes a submerged forward osmosis (FO) membrane module inside a bioreactors.

755 citations


Journal ArticleDOI
TL;DR: This research highlights the need to understand more fully the rationale behind the rapid decline in physical activity in middle-aged people over a longer period of time.
Abstract: Sarah L. Booth, Ph.D., Vitamin K Laboratory, Jean Mayer USDAHuman Nutrition Research Center on Aging at Tufts University, Boston, MA; James F. Sallis, Ph.D., F.A.C.S.M., Department ofPsychology, San Diego State University, San Diego, CA; Cheryl Ritenbaugh, Ph.D., M.P.H., Kaiser Permanente Center for Health Research, Portland, O R James 0. Hill, Ph.D., Center for Human Nutrition, University of Colorado Health Sciences Center, Denver, CO; Leann L. Birch, Ph.D., Department ofHuman Development and Family Studies, Pennsylvania State University, University Park, PA; Lawrence D. Frank, Ph.D., College OfArchitecture, Georgia Institute of Technology, Atlanta, GA; Karen Glanz, Ph.D., M.P.H., Cancer Research Center of Hawaii, University of Hawaii, Honolulu, HI; David A. Himmelgreen, Ph.D., Department ofAnthropology, University of South Florida, Tampa, FL; Michael Mudd, Corporate Affairs, Kraft Foods, Inc., Northfield, IL; Barry M. Popkin, Ph.D., Department ofNutrition, Carolina Population Center, University of North Carolina, Chapel Hill, NC; Karyl A. Rickard, Ph.D., R.D., C.S.P., F.A.D.A., Nutrition and Dietetics Program, School ofAllied Health Sciences, Indiana University School of Medicine, Indianapolis, IN; Sachiko St. Jeor, Ph.D., R.D., Nutrition Education and Research Program, University of Nevada School of Medicine, Reno, W, Nicholas P. Hays, M.S., Energy Metabolism Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA.

685 citations


Journal ArticleDOI
TL;DR: In this paper, a pressure retarded osmosis (PRO) model was developed to predict water flux and power density under specific experimental conditions, relying on experimental determination of the membrane water permeability coefficient (A), the membrane salt permeability coefficients (B), and the solute resistivity (K).

681 citations


Journal ArticleDOI
TL;DR: In this article, an analysis of the food industry showed that sustainability requires an expanded view to encompass both environmental and social elements, and that environmental performance improvements lead to improved quality performance, which in turn improves cost performance.
Abstract: Sustainable supply management research generally focuses on environmental practices. We show through an analysis of the food industry that sustainability requires an expanded view to encompass both environmental and social elements. We interviewed and surveyed food and beverage producers in the U.S. Pacific Northwest to both validate expanded sustainability elements in the industry and assess subsequent performance outcomes. A path analysis reveals that food industry managers perceive both direct and mediated impacts of sustainability programs on performance. Specifically, the results indicate that sustainability program effects are limited to the impact of conservation and land management environmental practices on overall environmental performance and human resources practices on quality performance. However, environmental performance improvements lead to improved quality performance, which in turn improves cost performance. The results highlight the complexity of sustainability impacts on performance and suggest that performance benefits from sustainability programs may be difficult to recognize.

520 citations


Journal ArticleDOI
TL;DR: In this article, two reverse osmosis (RO) brine streams with total dissolved solids concentrations averaging 7500 and 17,500 mg/L were further desalinated by VEDCMD and FO.

514 citations


Journal ArticleDOI
22 Oct 2009-Nature
TL;DR: The Pten–Ets2 axis is identified as a critical stroma-specific signalling pathway that suppresses mammary epithelial tumours and ameliorated disruption of the tumour microenvironment.
Abstract: The tumour stroma is believed to contribute to some of the most malignant characteristics of epithelial tumours. However, signalling between stromal and tumour cells is complex and remains poorly understood. Here we show that the genetic inactivation of Pten in stromal fibroblasts of mouse mammary glands accelerated the initiation, progression and malignant transformation of mammary epithelial tumours. This was associated with the massive remodelling of the extracellular matrix (ECM), innate immune cell infiltration and increased angiogenesis. Loss of Pten in stromal fibroblasts led to increased expression, phosphorylation (T72) and recruitment of Ets2 to target promoters known to be involved in these processes. Remarkably, Ets2 inactivation in Pten stroma-deleted tumours ameliorated disruption of the tumour microenvironment and was sufficient to decrease tumour growth and progression. Global gene expression profiling of mammary stromal cells identified a Pten-specific signature that was highly represented in the tumour stroma of patients with breast cancer. These findings identify the Pten-Ets2 axis as a critical stroma-specific signalling pathway that suppresses mammary epithelial tumours.

490 citations


Journal ArticleDOI
TL;DR: In this article, an analysis of high resolution OA spectra was performed at the T0 urban supersite in Mexico City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation.
Abstract: . Submicron aerosol was analyzed during the MILAGRO field campaign in March 2006 at the T0 urban supersite in Mexico City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation. Mass concentrations, diurnal cycles, and size distributions of inorganic and organic species are similar to results from the CENICA supersite in April 2003 with organic aerosol (OA) comprising about half of the fine PM mass. Positive Matrix Factorization (PMF) analysis of the high resolution OA spectra identified three major components: chemically-reduced urban primary emissions (hydrocarbon-like OA, HOA), oxygenated OA (OOA, mostly secondary OA or SOA), and biomass burning OA (BBOA) that correlates with levoglucosan and acetonitrile. BBOA includes several very large plumes from regional fires and likely also some refuse burning. A fourth OA component is a small local nitrogen-containing reduced OA component (LOA) which accounts for 9% of the OA mass but one third of the organic nitrogen, likely as amines. OOA accounts for almost half of the OA on average, consistent with previous observations. OA apportionment results from PMF-AMS are compared to the PM2.5 chemical mass balance of organic molecular markers (CMB-OMM, from GC/MS analysis of filters). Results from both methods are overall consistent. Both assign the major components of OA to primary urban, biomass burning/woodsmoke, and secondary sources at similar magnitudes. The 2006 Mexico City emissions inventory underestimates the urban primary PM2.5 emissions by a factor of ~4, and it is ~16 times lower than afternoon concentrations when secondary species are included. Additionally, the forest fire contribution is at least an order-of-magnitude larger than in the inventory.

472 citations


Journal ArticleDOI
TL;DR: In this article, the authors reviewed relevant literature which deals with various manifestations of energy absorption of composites from the nano to the macro-scale, with emphasis on the nano-scale.

472 citations


Journal ArticleDOI
TL;DR: The established mechanisms by which oxidative stress and environmental stressors regulate the apoptotic machinery are reviewed with the aim of underscore the relevance of apoptosis as a component in environmental toxicity and human disease progression.
Abstract: Apoptosis is an evolutionary conserved homeostatic process involved in distinct physiological processes including organ and tissue morphogenesis, development and senescence. Its deregulation is also known to participate in the etiology of several human diseases including cancer, neurodegenerative and autoimmune disorders. Environmental stressors (cytotoxic agents, pollutants or toxicants) are well known to induce apoptotic cell death and to contribute to a variety of pathological conditions. Oxidative stress seems to be the central element in the regulation of the apoptotic pathways triggered by environmental stressors. In this work, we review the established mechanisms by which oxidative stress and environmental stressors regulate the apoptotic machinery with the aim to underscore the relevance of apoptosis as a component in environmental toxicity and human disease progression.

Journal ArticleDOI
TL;DR: In this paper, a simple sonoelectrochemical anodization method was proposed to grow smooth and ultrathin (5−7 nm thick) Fe2O3 nanotube arrays (3−4 μm long) on Fe foil in as little as 13 min.
Abstract: One-dimensional nanostructures exhibit quantum confinement that leads to unique electronic properties, making them attractive as the active elements for various applications. Iron oxide (α-Fe2O3 or hematite) nanotubes are of particular interest in catalysis, sensor devices, Li-ion battery, environmental remediation and photocatalysis. Here, we report a simple sonoelectrochemical anodization method to grow smooth and ultrathin (5−7 nm thick) Fe2O3 nanotube arrays (3−4 μm long) on Fe foil in as little as 13 min. The prepared catalyst has shown tremendous potential to split water to generate hydrogen under solar light illumination. A photocurrent density of 1.41 mA/cm2 is observed for hematite nanotube arrays with more than 50% being contributed by the visible light components of the solar spectrum.

Journal ArticleDOI
TL;DR: Preliminary support for the role of acceptance and mindfulness in improving the quality of life of obese individuals while simultaneously augmenting their weight control efforts is provided.
Abstract: Background Obesity is a growing epidemic. Weight control interventions can achieve weight loss, but most is regained over time. Stigma and low quality of life are significant problems that are rarely targeted. Purpose A new model aimed at reducing avoidant behavior and increasing psychological flexibility, has shown to be relevant in the treatment of other chronic health problems and is worth examining for improving the lives of obese persons. Methods Patients who had completed at least 6 months of a weight loss program (N=84) were randomly assigned to receive a 1-day, mindfulness and acceptance-based workshop targeting obesity-related stigma and psychological distress or be placed on a waiting list. Results At a 3-month follow-up, workshop participants showed greater improvements in obesity-related stigma, quality of life, psychological distress, and body mass, as well as improvements in distress tolerance, and both general and weight-specific acceptance and psychological flexibility. Effects on distress, stigma, and quality of life were above and beyond the effects due to improved weight control. Mediational analyses indicated that changes in weight-specific acceptance coping and psychological flexibility mediated changes in outcomes. Conclusion Results provide preliminary support for the role of acceptance and mindfulness in improving the quality of life of obese individuals while simultaneously augmenting their weight control efforts.

Journal ArticleDOI
TL;DR: The metabolic responses of grapes to water deficit varied with the cultivar and fruit pigmentation, and changes in metabolism have important impacts on berry flavor and quality characteristics.
Abstract: Water deficit has significant effects on grape berry composition resulting in improved wine quality by the enhancement of color, flavors, or aromas. While some pathways or enzymes affected by water deficit have been identified, little is known about the global effects of water deficit on grape berry metabolism. The effects of long-term, seasonal water deficit on berries of Cabernet Sauvignon, a red-wine grape, and Chardonnay, a white-wine grape were analyzed by integrated transcript and metabolite profiling. Over the course of berry development, the steady-state transcript abundance of approximately 6,000 Unigenes differed significantly between the cultivars and the irrigation treatments. Water deficit most affected the phenylpropanoid, ABA, isoprenoid, carotenoid, amino acid and fatty acid metabolic pathways. Targeted metabolites were profiled to confirm putative changes in specific metabolic pathways. Water deficit activated the expression of numerous transcripts associated with glutamate and proline biosynthesis and some committed steps of the phenylpropanoid pathway that increased anthocyanin concentrations in Cabernet Sauvignon. In Chardonnay, water deficit activated parts of the phenylpropanoid, energy, carotenoid and isoprenoid metabolic pathways that contribute to increased concentrations of antheraxanthin, flavonols and aroma volatiles. Water deficit affected the ABA metabolic pathway in both cultivars. Berry ABA concentrations were highly correlated with 9-cis-epoxycarotenoid dioxygenase (NCED1) transcript abundance, whereas the mRNA expression of other NCED genes and ABA catabolic and glycosylation processes were largely unaffected. Water deficit nearly doubled ABA concentrations within berries of Cabernet Sauvignon, whereas it decreased ABA in Chardonnay at veraison and shortly thereafter. The metabolic responses of grapes to water deficit varied with the cultivar and fruit pigmentation. Chardonnay berries, which lack any significant anthocyanin content, exhibited increased photoprotection mechanisms under water deficit conditions. Water deficit increased ABA, proline, sugar and anthocyanin concentrations in Cabernet Sauvignon, but not Chardonnay berries, consistent with the hypothesis that ABA enhanced accumulation of these compounds. Water deficit increased the transcript abundance of lipoxygenase and hydroperoxide lyase in fatty metabolism, a pathway known to affect berry and wine aromas. These changes in metabolism have important impacts on berry flavor and quality characteristics. Several of these metabolites are known to contribute to increased human-health benefits.

Journal ArticleDOI
TL;DR: In this article, a lobster pine was treated by wet torrefaction (hot compressed water, 200-260°C) and dry torrefraction (nitrogen, 250-300°C), with mass yield of solid product ranging between 57 and 89%.
Abstract: Torrefaction is a process to convert diverse lignocellulosic biomass feedstocks into an energy dense homogeneous solid, a pretreatment for subsequent thermochemical conversion. Loblolly pine was treated by wet torrefaction (hot compressed water, 200–260°C) and dry torrefaction (nitrogen, 250–300°C), with mass yield of solid product ranging between 57 and 89%, and energy densification to 108–136% of the original feedstock. The solid product has been characterized, including proximate analysis, fiber analysis, ultimate analysis, and equilibrium moisture. In both dry and wet torrefaction, increasing temperature results in decreased mass yield and increased energy densification, and results in a solid with increased carbon content, decreased oxygen content, and decreased volatiles. The biomass is transformed into a fuel similar to a low-rank coal. Generally, the wet torrefaction process produces a solid with greater energy density than dry torrefaction, with the same mass yield. The fiber analysis indicates that hemicellulose is quickly removed during wet torrefaction, and the solid product contains substantial quantities of aqueous soluble compounds. The equilibrium moisture content of solids produced by both processes is somewhat decreased from that of the biomass feedstock, indicating a hydrophobic solid suitable for storage and transportation. © 2009 American Institute of Chemical Engineers Environ Prog, 2009

Journal ArticleDOI
TL;DR: In particular, inversion-based control can find the feedforward input needed to account for the positioning dynamics and, thus, achieve the required precision and bandwidth as mentioned in this paper, which can substantially impact the throughput of a wide range of emerging nanosciences and nanotechnologies.
Abstract: Control can enable high-bandwidth nanopositioning needed to increase the operating speed of scanning probe microscopes (SPMs). High-speed SPMs can substantially impact the throughput of a wide range of emerging nanosciences and nanotechnologies. In particular, inversion-based control can find the feedforward input needed to account for the positioning dynamics and, thus, achieve the required precision and bandwidth. This article reviews inversion-based feedforward approaches used for high-speed SPMs such as optimal inversion that accounts for model uncertainty and inversion-based iterative control for repetitive applications. The article establishes connections to other existing methods such as zero-phase-error-tracking feedforward and robust feedforward. Additionally the article reviews the use of feedforward in emerging applications such as SPM-based nanoscale combinatorial-science studies, image-based control for subnanometer-scale studies, and imaging of large soft biosamples with SPMs.

Journal ArticleDOI
TL;DR: The fundamental role of ANO1 is demonstrated in the generation of slow waves in GI ICC, which failed to develop by birth in mice homozygous for a null allele of Tmem16a and did not develop subsequent to birth in organ culture, as in wildtype and heterozygous muscles.
Abstract: Specialized cells, referred to as interstitial cells of Cajal (ICC), generate and actively propagate the spontaneous electrical activity known as slow waves in the gastrointestinal (GI) tract (Ward et al. 1994, Huizinga et al. 1995; Sanders, 1996). Slow waves time the phasic contractions of GI muscles and provide the underlying organization of excitability for gastric peristalsis and intestinal segmentation. ICC are also interposed between nerve terminals and smooth muscle cells and serve as sites of post-junctional transduction of responses to enteric motor neurotransmitters (see Burns et al. 1996; Ward et al. 2000a). There are at least two classes of ICC, those intermingled within muscle bundles of the circular (CM) and longitudinal muscle (LM) layers (ICC-IM), and those arranged in a dense network between the CM and LM (ICC-MY), at the submucosal surface of the CM (ICC-SM) and in the septa between bundles of smooth muscle cells (ICC-SEP). There have been many studies regarding the mechanisms of pacemaker activity and slow wave propagation, but the precise mechanisms of this behaviour remain controversial. Studies of pacemaker activity in intact muscle strips and bundles have suggested the involvement of a Ca2+-dependent inward current because activity was reduced when the muscles were treated with membrane-permeable Ca2+ buffers (Edwards et al. 1999; Hirst et al. 2002; Kito & Suzuki, 2003). The Ca2+-dependent conductance has been thought to be a Cl− conductance, since a variety of Cl− channel blocking drugs reduced pacemaker activity in guinea-pig and murine muscles (see Hirst et al. 2002; Kito et al. 2002a; Kito & Suzuki, 2003). Similar conclusions were reached from studies of slow waves recorded directly from ICC-MY of the small intestine (e.g. Kito & Suzuki, 2003). In contrast, studies of isolated and cultured ICC have suggested that spontaneous activity is generated by activation of a non-selective cation conductance (Ward et al. 2000; Koh et al. 2002; Sanders et al. 2006), and the putative conductance was found to be inhibited by Ca2+ (Koh et al. 2002). Thus, pacemaker current may be initiated by a transient reduction in [Ca2+]i in a sub-compartment under the plasma membrane containing the non-selective cation conductance (Sanders et al. 2006). No Ca2+-activated inward currents were observed in cultured ICC, and the non-selective cation channels activated by reduced Ca2+ were inhibited by niflumic acid (Koh et al. 2002). Thus, use of Cl− channel antagonists does not necessarily indicate a role for Ca2+- activated Cl− channels in pacemaker activity. A microarray genetic screen recently revealed that Tmem16a is expressed at far greater levels in ICC than in the rest of the muscularis (Chen et al. 2007). Tmem16a encodes ANO1, a Ca2+-activated Cl− channel (Caputo et al. 2008; Schroeder et al. 2008; Yang et al. 2008), and immunohistochemical studies have documented expression of ANO1 (also known as DOG1) protein by ICC (Espinosa et al. 2008; Gomez-Pinilla et al. 2009). Taken together these data suggest the hypothesis that expression and function of these channels may be important in pacemaker activity in the GI tract. Therefore, we have characterized expression of Tmem16a transcripts and ANO1 protein in the tunica muscularis of mouse, monkey (Macaca fascicularis) and human GI tracts using RT-PCR, amplicon sequencing and immunohistochemical techniques. We also evaluated the electrical activity of murine gastric and small intestine muscles, and tested the effects of Cl− channel-blocking drugs. Finally, we tested whether slow wave activity is affected in mice homozygous with null Tmem16a alleles (Tmem16atm1Bdh/tm1Bdh, see Rock et al. 2008). Our data show ubiquitous expression of ANO1 in ICC throughout the GI tract and inhibitory effects of Cl− channel blocking drugs on slow waves. Tmem16a−/− animals failed to generate slow waves, and pacemaker activity did not develop in organ culture after birth, as occurs in wildtype muscles. Together with voltage-clamp studies of isolated ICC (Zhu et al. 2009), our findings strongly support a role for ANO1 in the generation of slow wave currents of GI ICC and electrical slow waves in intact muscles. The model of pacemaker activity deduced from previous studies of cultured ICC (e.g. as detailed in Sanders et al. 2006) will require reconsideration in light of these new findings.


Journal ArticleDOI
TL;DR: This review will combine an analysis of microarray data with information available on protein and enzyme activity patterns in grapes and other fruits, to explore pathways through which malate is conditionally metabolised, and how these may be controlled in response to developmental and climatic changes.

Journal ArticleDOI
TL;DR: An assessment of the ability of the dynamic capabilities view to explain successful change with logical consistency, conceptual clarity and empirical rigor is taken and four major problems are identified that limit the potential contribution of the DCV.
Abstract: Why do some firms succeed in a dynamic competitive environment when others fail? Recently, concepts and models addressing this question have increasingly clustered around the dynamic capabilities view (DCV). Citation counts suggest that the DCV is the new touchstone firm-based performance-focused theory (Teece et al. [1997], for example, had received 1180 citations in the ISI Web of Knowledge as of June 2008), and case studies of innovative firms such as IDEO (Hargadon and Sutton, 1997) have fueled interest. We take a step back to assess the ability of the DCV to explain successful change with logical consistency, conceptual clarity and empirical rigor, criteria suggested by Laudan (1977). Such an assessment is important not only because of the DCV’s popularity, but also because of the theoretical and practical significance of the issues it addresses. While the arguably static resource-based view (RBV) emphasizes the value of resources, the DCV addresses the need to explain changes in valuable resources, e.g. the erosion of asset stocks (Dierickx and Cool, 1989) and the changes in asset values (Miller and Shamsie, 1996). The DCV also addresses a practical need to understand how firms can change effectively, given perceptions that many competitive environments now change at increasing rates, and that firms have difficulty changing successfully (Beer and Nohria, 2000; Strebel, 1996). Our assessment identifies four major problems that limit the potential contribution of the DCV: (1) unclear value-added relative to existing concepts; (2) lack of a coherent theoretical foundation; (3) weak empirical support; and (4) unclear practical implications. Although potentially interrelated, each problem presents different difficulties and raises different questions.

Journal ArticleDOI
TL;DR: The proof of principle of the rectification degree-based sensing was shown by preparation of sensors for avidin and streptavidin and the devices allowed for determination of the isoelectric point of the minute amounts of proteins immobilized on the surface.
Abstract: Recently reported nanofluidic diodes with highly nonlinear current−voltage characteristics offer a unique possibility to construct different biosensors. These sensors are based on local changes of the surface charge on walls of single conical nanopores induced by binding of an analyte. The analyte binding can be detected as a change of the ion-current rectification of single nanopores defined as a ratio of currents for voltages of one polarity, and currents for voltages of the opposite polarity. In this article, we provided both modeling and experimental studies of various biosensing routes based on monitoring changes of the rectification degree in nanofluidic diodes used as a biosensing platform. A prototype of a sensor for the capsular poly γ-d-glutamic acid (γDPGA) from Bacillus anthracis is presented. The nanopore used for the sensing was locally modified with the monoclonal antibody for γDPGA. The proof of principle of the rectification degree-based sensing was further shown by preparation of sensors...

Journal ArticleDOI
TL;DR: In this article, the authors focus on providing the hydrologic user with sufficient knowledge and specifications to allow sound decisions on the application and deployment of distributed temperature sensing (DTS) systems.
Abstract: [1] Raman spectra distributed temperature sensing (DTS) by fiber-optic cables has recently shown considerable promise for the measuring and monitoring of surface and near-surface hydrologic processes such as groundwater–surface water interaction, borehole circulation, snow hydrology, soil moisture studies, and land surface energy exchanges. DTS systems uniquely provide the opportunity to monitor water, air, and media temperatures in a variety of systems at much higher spatial and temporal frequencies than any previous measurement method. As these instruments were originally designed for fire and pipeline monitoring, their extension to the typical conditions encountered by hydrologists requires a working knowledge of the theory of operation, limitations, and system accuracies, as well as the practical aspects of designing either short- or long-term experiments in remote or challenging terrain. This work focuses on providing the hydrologic user with sufficient knowledge and specifications to allow sound decisions on the application and deployment of DTS systems.

Journal ArticleDOI
TL;DR: Four current control structures for selective harmonic compensation in active power filters are compared and it emerges that the fourth one has superior behavior and robustness and can stably work at higher frequencies than the others.
Abstract: This paper compares four current control structures for selective harmonic compensation in active power filters. All controllers under scrutiny perform the harmonic compensation by using arrays of resonant controllers, one for the fundamental and one for each harmonic of interest, in order to achieve zero phase shift and unity gain in the closed-loop transfer function for selected harmonics. The complete current controller is the superposition of all individual harmonic controllers and may be implemented in various reference frames. The analysis is focused on the comparison of harmonic and total closed-loop transfer functions for each controller. Analytical similarities and differences between schemes in terms of frequency response characteristics are emphasized. It is concluded that three of them have identical harmonic behavior despite the fact that their implementation is significantly different. It emerges that the fourth one has superior behavior and robustness and can stably work at higher frequencies than the others. Theoretical findings and analysis are supported by comparative experimental results on a 7-kVA laboratory setup. The highest harmonic frequency that can be stably compensated with each control method has been determined, indicating significant differences in the control performance.

Journal ArticleDOI
TL;DR: This chemistry reveals the synthetic potential of incorporating gold(I)/gold(III) catalytic cycles into contemporary gold chemistry and promises a new area of gold research by merging powerful gold catalysis and oxidative metal-catalyzed cross-coupling reactions.
Abstract: Oxidizing gold? A gold(I)/gold(III) catalytic cycle is essential for the first oxidative cross-coupling reaction in gold catalysis. By using Selectfluor for gold(I) oxidation, this chemistry reveals the synthetic potential of incorporating gold(I)/gold(III) catalytic cycles into contemporary gold chemistry and promises a new area of gold research by merging powerful gold catalysis and oxidative metal-catalyzed cross-coupling reactions.

Journal ArticleDOI
TL;DR: An update of this emergent field of hybridization, based both on the papers in this volume and on the relevant literature, considers how its examples suggest mechanisms whereby hybridization may act to stimulate the evolution of invasiveness.
Abstract: Less than a decade ago, we proposed that hybridization could serve as a stimulus for the evolution of invasiveness in plants (Ellstrand and Schierenbeck Proc Nat Acad Sci USA 97:7043–7050, 2000). A substantial amount of research has taken place on that topic since the publication of that paper, stimulating the symposium that makes up this special issue. Here we present an update of this emergent field, based both on the papers in this volume and on the relevant literature. We reevaluate the lists that we presented in our earlier paper of reports in which hybridization has preceded the evolution of invasiveness. We discard a few cases that were found to be in error, published only as abstracts, or based on personal communication. Then we augment the list from examples in this volume and a supplementary literature search. Despite the omissions, the total number of cases has increased. Many have been strengthened. We add a list of cases in which there has been evidence that intra-taxon hybridization has preceded the evolution of invasiveness. We also provide a number of examples from organisms other than plants. We consider how our examples suggest mechanisms whereby hybridization may act to stimulate the evolution of invasiveness. Hybridization does not represent the only evolutionary pathway to invasiveness, but it is one that can explain why the appearance of invasiveness often involves a long lag time and/or multiple introductions of exotics.

Journal ArticleDOI
TL;DR: In this brief review, some insight is provided into what the authors currently know about the health problems associated with various air pollutants and their relationship in promoting chronic diseases through changes in oxidative stress and modulation of gene expression.
Abstract: Air pollutants have, and continue to be, major contributing factors to chronic diseases and mortality, subsequently impacting public health. Chronic diseases include: chronic obstructive pulmonary diseases (COPD), cardiovascular diseases (CVD), asthma, and cancer. Byproducts of oxidative stress found in air pollutants are common initiators or promoters of the damage produced in such chronic diseases. Such air pollutants include: ozone, sulfur oxides, carbon monoxide, nitrogen oxides, and particulate matter. Interaction between oxidative stress byproducts and certain genes within our population may modulate the expression of specific chronic diseases. In this brief review we attempt to provide some insight into what we currently know about the health problems associated with various air pollutants and their relationship in promoting chronic diseases through changes in oxidative stress and modulation of gene expression. Such insight eventually may direct the means for effective public health prevention and treatment of diseases associated with air pollution and treatment of diseases associated with air pollution.

Journal ArticleDOI
TL;DR: These studies suggest that thiamin and TPP function as important stress-response molecules that alleviate oxidative stress during different abiotic stress conditions.
Abstract: Thiamin and thiamin pyrophosphate (TPP) are well known for their important roles in human nutrition and enzyme catalysis. In this work, we present new evidence for an additional role of these compounds in the protection of cells against oxidative damage. Arabidopsis (Arabidopsis thaliana) plants subjected to abiotic stress conditions, such as high light, cold, osmotic, salinity, and oxidative treatments, accumulated thiamin and TPP. Moreover, the accumulation of these compounds in plants subjected to oxidative stress was accompanied by enhanced expression of transcripts encoding thiamin biosynthetic enzymes. When supplemented with exogenous thiamin, wild-type plants displayed enhanced tolerance to oxidative stress induced by paraquat. Thiamin application was also found to protect the reactive oxygen species-sensitive ascorbate peroxidase1 mutant from oxidative stress. Thiamin-induced tolerance to oxidative stress was accompanied by decreased production of reactive oxygen species in plants, as evidenced from decreased protein carbonylation and hydrogen peroxide accumulation. Because thiamin could protect the salicylic acid induction-deficient1 mutant against oxidative stress, thiamin-induced oxidative protection is likely independent of salicylic acid signaling or accumulation. Taken together, our studies suggest that thiamin and TPP function as important stress-response molecules that alleviate oxidative stress during different abiotic stress conditions.

Journal ArticleDOI
TL;DR: A role for a Ca2+‐activated Cl− conductance in slow wave current in ICC is demonstrated and is consistent with the idea that ANO1 participates in pacemaker activity.
Abstract: Interstitial cells of Cajal (ICC) are unique cells that generate electrical pacemaker activity in gastrointestinal (GI) muscles. Many previous studies have attempted to characterize the conductances responsible for pacemaker current and slow waves in the GI tract, but the precise mechanism of electrical rhythmicity is still debated. We used a new transgenic mouse with a bright green fluorescent protein (copGFP) constitutively expressed in ICC to facilitate study of these cells in mixed cell dispersions. We found that ICC express a specialized ‘slow wave’ current. Reversal of tail current analysis showed this current was due to a Cl− selective conductance. ICC express ANO1, a Ca2+-activated Cl− channel. Slow wave currents are not voltage dependent, but a secondary voltage-dependent process underlies activation of these currents. Removal of extracellular Ca2+, replacement of Ca2+ with Ba2+, or extracellular Ni2+ (30 μm) blocked the slow wave current. Single Ca2+-activated Cl− channels with a unitary conductance of 7.8 pS were resolved in excised patches of ICC. These are similar in conductance to ANO1 channels (8 pS) expressed in HEK293 cells. Slow wave current was blocked in a concentration-dependent manner by niflumic acid (IC50= 4.8 μm). Slow wave currents are associated with transient depolarizations of ICC in current clamp, and these events were blocked by niflumic acid. These findings demonstrate a role for a Ca2+-activated Cl− conductance in slow wave current in ICC and are consistent with the idea that ANO1 participates in pacemaker activity.

Journal ArticleDOI
TL;DR: It is shown here that overexpression of MsProDH in tobacco and Arabidopsis or impairment of P5C oxidation in theArabidopsis p5cdh mutant did not change the cellular Pro to P5c ratio under ambient and osmotic stress conditions, indicating that P5 C excess was reduced to Pro in a mitochondrial-cytosolic cycle.

Journal ArticleDOI
10 Mar 2009
TL;DR: In this article, the authors reported on the detection by Swift of GRB 080913, and subsequent optical/near-infrared follow-up observations by GROND, which led to the discovery of its optical/NIR afterglow and the recognition of its high-z nature via the detection of a spectral break between the i' and z' bands.
Abstract: We report on the detection by Swift of GRB 080913, and subsequent optical/near-infrared follow-up observations by GROND, which led to the discovery of its optical/NIR afterglow and the recognition of its high-z nature via the detection of a spectral break between the i' and z' bands. Spectroscopy obtained at the ESO-VLT revealed a continuum extending down to lambda = 9400 angstrom, and zero flux for 7500 angstrom< lambda < 9400 angstrom, which we interpret as the onset of a Gunn-Peterson trough at z = 6.695 +/- 0.025 (95.5% confidence level), making GRB 080913 the highest-redshift gamma-ray burst (GRB) to date, and more distant than the highest-redshift QSO. We note that many redshift indicators that are based on promptly available burst or afterglow properties have failed for GRB 080913. We report on our follow-up campaign and compare the properties of GRB 080913 with bursts at lower redshift. In particular, since the afterglow of this burst is fainter than typical for GRBs, we show that 2 m class telescopes can identify most high-redshift GRBs.