bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect Of Summarization On Intermediate EFL Learners Reading Comprehension And Their Performance On Display, Referential And Inferential Questions
Authors: Ghabanchi Zargham , Mirza Fateme Haji
Published: March 2016

This study examined the effect of summarization as a generative learning strategy of the readers' performance on reading comprehension, in general, and reading comprehension display, referential and inferential questions in particular. The subjects in this study were 61 high school students. They were assigned to two groups - control and experimental – each given the same texts taught by one of the researchers during ten sessions. In the control group, learners automatically used their own self-preferred strategies; but the experimental group was taught how to summarize the paragraphs. Then all were post-tested on their achievement of the instructed texts. The results revealed that the use of summarization did not have a significant effect on the readers' performance on display and inferential questions. As for the referential questions, however, the results demonstrated a significant effect for the use of summarization.
Statistical downscaling of general circulation model outputs to precipitation, evaporation and temperature using a key station approach
Authors: Sachindra D. A. , Huang F. , Barton A. , Perera B. J. C.
Published: March 2016

Using a key station approach, statistical downscaling of monthly general circulation model outputs to monthly precipitation, evaporation, minimum temperature and maximum temperature at 17 observation stations located in Victoria, Australia was performed. Using the observations of each predictand, over the period 1950–2010, correlations among all stations were computed. For each predictand, the station which showed the highest number of correlations above 0.80 with other stations was selected as the first key station. The stations that were highly correlated with that key station were considered as the member stations of the first cluster. By employing this same procedure on the remaining stations, the next key station was found. This procedure was performed until all stations were segregated into clusters. Thereafter, using the observations of each predictand, regression equations (inter-station regression relationships) were developed between the key stations and the member stations for each calendar month. The downscaling models at the key stations were developed using reanalysis data as inputs to them. The outputs of HadCM3 pertaining to A2 emission scenario were introduced to these downscaling models to produce projections of the predictands over the period 2000–2099. Then the outputs of these downscaling models were introduced to the inter-station regression relationships to produce projections of predictands at all member stations.
Differences in In Vivo Cellular Kinetics in Abdominal and Femoral Subcutaneous Adipose Tissue in Women
Authors: White Ursula A. , Fitch Mark D. , Beyl Robbie A. , Hellerstein Marc K. , Ravussin Eric
Published: March 2016

The accumulation of fat in upper-body (abdominal) adipose tissue is associated with obesity-related cardiometabolic diseases, whereas lower-body (gluteal and femoral) fat may be protective. Studies suggest physiological and molecular differences between adipose depots and depot-specific cellular mechanisms of adipose expansion. We assessed in vivo cellular kinetics in subcutaneous adipose tissue from the abdominal (scABD) and femoral (scFEM) depots using an 8-week incorporation of deuterium (2H) from 2H2O into the DNA of adipocytes and preadipocytes in 25 women with overweight or obesity. DNA synthesis rates denote new cell formation of preadipocytes and adipocytes in each depot. Formation of adipocytes was positively correlated to that of preadipocytes in the scABD and scFEM depots and was related to percent body fat in each depot. Notably, preadipocytes and adipocytes had higher formation rates in the scFEM depot relative to the scABD. This method to assess in vivo adipogenesis will be valuable to evaluate adipocyte kinetics in individuals with varying body fat distributions and degrees of metabolic health and in response to a variety of interventions, such as diet, exercise, or pharmacological treatment.
Brain Lactate Concentration Falls in Response to Hypoglycemia in Patients With Type 1 Diabetes and Impaired Awareness of Hypoglycemia
Authors: Wiegers Evita C. , Rooijackers Hanne M. , Tack Cees J. , Heerschap Arend , de Galan Bastiaan E. , van der Graaf Marinette
Published: March 2016

Brain lactate may be involved in the development of impaired awareness of hypoglycemia (IAH), a condition that affects approximately 25% of patients with type 1 diabetes and increases the risk of severe hypoglycemia. The aim of this study was to investigate the effect of acute hypoglycemia on brain lactate concentration in patients with IAH as compared with those with normal awareness of hypoglycemia (NAH) and healthy control subjects (n = 7 per group). After an overnight fast, all subjects underwent a two-step hyperinsulinemic euglycemic (5.0 mmol/L)–hypoglycemic (2.8 mmol/L) glucose clamp. Brain lactate concentrations were measured continuously with 1H-MRS using a specific lactate detection method. Hypoglycemia generated symptoms in patients with NAH and healthy control subjects but not in patients with IAH. Brain lactate fell significantly by ∼20% in response to hypoglycemia in patients with type 1 diabetes with IAH but remained stable in both healthy control subjects and in patients with NAH. The fall in brain lactate is compatible with increased brain lactate oxidation providing an alternative fuel source during hypoglycemia, which may contribute to the impaired detection of hypoglycemia.
Phytochemical investigation and in vitro antimicrobial activity of Richardia scabra
Authors: Poonkodi Kathirvel , Ravi Subban
Published: March 2016

The present study was aimed to evaluate the phytochemical screening and antimicrobial activity of the petroleum ether and methanol extracts from the mature leaves of Richardia scabra from India. Disc diffusion method was used to determine the zone inhibition of the tested samples for antibacterial and agar plug method was used to determine the antifungal activity, while the microtube-dilution technique was used to determine the minimum inhibitory concentration. Both extracts showed significant antibacterial and antifungal activities when tested against 10 bacterial and four fungal strains. The minimum inhibitory concentrations of the methanol extract of R. scabra ranged between 12.5–100 μg/mL for bacterial strains. Alkaloids, steroids, flavonoids, fatty acids, terpenoids and simple sugar were detected as phytoconstituents of extracts. To the best of our knowledge, this is the first report against antimicrobial activity of common weed species R. scabra found in India.

 
Les développements récents de la littérature sur les plates-formes
Authors: Verdier Marianne
Published: March 2016

Cet article offre une synthèse de la littérature sur les marchés de plates-formes. De nouvelles avancées ont permis de généraliser les modèles fondateurs de Rochet et Tirole [2003] et d’Armstrong [2006] et d’élargir les sujets de recherches à des questions diverses comme celle de la mesure du pouvoir de marché en présence d’externalités croisées, ou encore l’effet sur le surplus social des ventes liées. Ces résultats peuvent guider l’analyse menée par les régulateurs et les autorités de la concurrence vers de nouvelles conclusions.
Licensing Commitments in Standard Setting Organizations
Authors: Lévêque François , Ménière Yann
Published: March 2016

Les organismes de standardisation ont mis en place des politiques ad hoc imposant aux propriétaires de brevets dits « essentiels » à un standard de s’engager ex ante à licencier ces brevets à des conditions raisonnables et non discriminatoires. Toutefois, la capacité de ces engagements à protéger réellement les utilisateurs du standard contre le hold-up est controversée. Dans cet article, nous développons un modèle permettant d’analyser l’effet d’engagements FRAND non contraignants, et de les comparer avec des engagements contraignants sur un niveau de redevance ou un plafond de redevance. Nous montrons que l’engagement sur un tel plafond est systématiquement préféré par le propriétaire de brevets, et qu’il a des effets ambigus sur les consommateurs en fonction de la stratégie alternative préférée du donneur de licence. JEL Codes: K21, L.
Transient Surface CCR5 Expression by Naive CD8+ T Cells within Inflamed Lymph Nodes Is Dependent on High Endothelial Venule Interaction and Augments Th Cell–Dependent Memory Response
Authors: Askew David , Su Charles A. , Barkauskas Deborah S. , Dorand R. Dixon , Myers Jay , Liou Rachel , Nthale Joseph , Huang Alex Y.
Published: March 2016

In inflamed lymph nodes, Ag-specific CD4+ and CD8+ T cells encounter Ag-bearing dendritic cells and, together, this complex enhances the release of CCL3 and CCL4, which facilitate additional interaction with naive CD8+ T cells. Although blocking CCL3 and CCL4 has no effect on primary CD8+ T cell responses, it dramatically impairs the development of memory CD8+ T cells upon Ag rechallenge. Despite the absence of detectable surface CCR5 expression on circulating native CD8+ T cells, these data imply that naive CD8+ T cells are capable of expressing surface CCR5 prior to cognate Ag-induced TCR signaling in inflamed lymph nodes; however, the molecular mechanisms have not been characterized to date. In this study, we show that CCR5, the receptor for CCL3 and CCL4, can be transiently upregulated on a subset of naive CD8+ T cells and that this upregulation is dependent on direct contact with the high endothelial venule in inflamed lymph node. Binding of CD62L and CD11a on T cells to their ligands CD34 and CD54 on the high endothelial venule can be enhanced during inflammation. This enhanced binding and subsequent signaling promote the translocation of CCR5 molecules from intracellular vesicles to the surface of the CD8+ T cell. The upregulation of CCR5 on the surface of the CD8+ T cells increases the number of contacts with Ag-bearing dendritic cells, which ultimately results in increased CD8+ T cell response to Ag rechallenge.
Peculiar/Unusual Perceptions and Beliefs and Covariation Detection
Authors: Berenbaum Howard
Published: March 2016

The present research explored the possibility that peculiar/unusual perceptions and/or beliefs might be associated with covariation detection. One-hundred thirty-five college students completed the Perceptual Aberration and Magical Ideation scales. They also performed a task in which they were presented with unpleasant images and asked to indicate whether the image was upright or rotated; participants were told the task was examining the impact of distraction on visual processing. In fact, loud noises were paired disproportionately with images of automobile accidents. After completing the task, participants were asked to identify the type of image that had been paired disproportionately with the loud noises. Participants who successfully detected the covariation had significantly higher Perceptual Aberration scale scores than did participants who did not detect the covariation.
“It's not just about being judged”: Interpersonal distrust uniquely contributes to social anxiety
Authors: Fetzner Mathew G. , Teale Sapach Michelle J. N. , Mulvogue Myriah , Carleton R. Nicholas
Published: March 2016

Fears of evaluation are central to defining social anxiety disorder (SAD); notwithstanding, evidence suggests that interpersonal distrust and perceived ineffectiveness are distinct constructs, prevalent among individuals with SAD. To date, no studies have assessed the independent contributions of interpersonal distrust and perceived ineffectiveness to SAD severity beyond fears of evaluation. In total 151 community-dwelling adults (80% women) with anxiety histories completed questionnaires as part of a larger study. Hierarchal regression analyses indicated that interpersonal distrust, but not perceived ineffectiveness, contributed significant amounts of variance to SAD severity after partitioning out variance from depressive symptoms and fear of negative and positive evaluation. Concertedly, findings suggest that although fears of evaluation are seminal to SAD severity, distrust of others may also uniquely exacerbate symptoms of social anxiety. Clinical and research implications are discussed herein.
Rumination in Everyday Life: The Influence of Distancing, Immersion, and Distraction
Authors: Yasinski Carly , Hayes Adele M. , Laurenceau Jean-Philippe
Published: March 2016

Rumination has been consistently associated with the development and maintenance of a variety of psychological disorders. While recent research has investigated a number of strategies to counter rumination and its negative effects, few have investigated their efficacy outside of a clinical or laboratory context. The current study used a daily diary methodology to compare the efficacy of three such strategies in the everyday lives of a highly ruminative sample. Over the course of 10 days, participants (N = 154) were asked to apply one of three perspectives (distanced, immersed, or distraction) to their thoughts and emotions about the most stressful event of the day and then to write a short narrative about the event. Over the 10-day period, immersion was associated with an average increase in negative emotion from before to after the narrative, whereas distancing was associated with little reactivity, and distraction was associated with a decrease in negative emotion. Participants in the distanced condition showed less ruminative, unproductive processing and used fewer negative emotion words in the narratives than those in the immersed condition. These differences were maintained over the 10-day study period. In targeted analyses of the days with the highest level of ruminative processing and/or event-related stress for each individual, the distanced and immersed groups reported similar levels of negative emotion reactivity and word use, but the distanced group showed less ruminative processing in the narratives. An interaction emerged suggesting that ruminative processing was only associated with an increase in negative emotion in the immersed group and not in the distanced group. The findings are discussed in the context of decreasing risk for depression and related disorders by targeting emotion regulation strategies on a daily level.
Intolerance of Uncertainty Mediates the Relationship between Panic and the Startle Reflex in Anticipation of Unpredictable Threat
Authors: Nelson Brady D. , Liu Huiting , Sarapas Casey , Shankman Stewart A.
Published: March 2016

The present study examined whether intolerance of uncertainty (IU) was associated with the startle reflex in anticipation of unpredictable threat, and whether IU mediated the relationship between panic and sensitivity to unpredictable threat. This was tested in separate samples of 86 undergraduates with varying panic symptoms and 148 adults with current panic disorder or no lifetime history of an anxiety disorder. Participants completed the Intolerance of Uncertainty Scale, which measures cognitive distress (prospective IU) and behavioral inhibition (inhibitory IU) elicited by uncertainty, and a no, predictable, and unpredictable threat-of-shock startle paradigm. In both samples prospective IU was associated with heightened startle during the unpredictable (but not predictable) condition, and in the clinical sample inhibitory IU was associated with attenuated startle during the unpredictable condition. IU mediated the relationship between panic and startle to unpredictable threat. These results support IU as a potential mechanism linking panic and sensitivity to unpredictable threat.
It's all about Control: Memory Bias in Anxiety is Restricted to Threat Cues that Signal Controllable Danger
Authors: Large Benita , MacLeod Colin , Clarke Patrick J.F. , Notebaert Lies
Published: March 2016

Although cognitive models of emotion propose that elevated trait anxiety may be associated with a memory bias for threatening information, evidence for such an anxiety-linked memory bias has been highly inconsistent. Given the crucial role of anxiety in preparing individuals to deal with impending danger, we hypothesized that an anxiety-linked memory bias may be restricted to cues that signal danger which can be controlled. High and low trait anxious participants performed a memory task in which three sets of neutral words were presented. These words acted as either controllable threat cues (signaled a loud noise burst that could be avoided through a secondary task), uncontrollable threat cues (signaled an unavoidable noise burst), or non-threat cues (did not signal a noise bursts). As hypothesized, high anxious participants showed better recognition of controllable threat cues as compared to non-threat cues, whereas no memory bias for uncontrollable threat cues was observed. No memory bias for either type of threat cue was observed in low anxious participants. Future research directions into the relationship between anxiety-linked memory bias and danger controllability are discussed.
Child Abuse and Neglect: Psychological Impact and Role of Social Work
Authors: Fahrudin Adi , Yusuf Husmiati , Malek Mohd Dahlan H. A.
Published: March 2016

Child welfare is considered a special area of practice within the profession of social work, and the principles and values of the social work profession generally fit with policies that guide modern child welfare organizations. In most countries, social workers in child welfare agencies have a minimum of a requirement and are registered with a government body that holds them accountable for competent and ethical practice. Child abuse can affect personality growth and later adult behavior. A social worker is closely connected with the study of causes, with treatment and associated research. Underpinning that mission is the belief that all societies have a duty to aim for an abuse-free environment. It needs to be recognized by students that working in this area can be very stressful for the professionals concerned. Interventions require exposure to deviant and stressful situations, which can, over time, affect the mental health of workers themselves. In some situations, dealing with criminal perpetrators can also be threatening and dangerous.
The Relationship between Exports and Economic Growth in Saudi Arabia
Authors: Alkhateeb Tarek Tawfik Yousef , Mahmood Haider , Sultan Zafar Ahmad
Published: March 2016

One of the most important objectives of an economy is to achieve high rate of economic growth so as to improve the well-being of their citizen. For the purpose, export-oriented policy measures are more preferably prescribed in the recent past. The present study aims at to find the linkages between exports and economic growth in case of Saudi Arabia. The study uses the most efficient unit root, cointegration and causality tests to find the true relationships between exports and economic growth. The study tries to examine the dynamic association for exports and economic growth in Saudi Arabia. Applying more popular time series technique of long run relationship and causality, the paper finds the long-run cointegration relationships in our export-growth model. Further, we have found feed-back effect in export-growth relationships and suggest the further export-promotion to foster economic growth in Saudi Arabia. 
The Possibility of Transplanting Western Bankruptcy Principles to Oman
Authors: AlBarashdi Saleh Hamed
Published: March 2016

This article investigates the extent of possible transplantation of some western bankruptcy principles to Oman. Such principles include the concept of rescue culture, the notion of ‘cram-down’, imposition of stay on secured creditors’ claims and the concept of ‘debtor-in-possession’. It demonstrates the fact that since the start of the legislation path in Oman in 1973, Oman tends to transplant some legal western concepts and such transplantation is accepted. However, the author supports the view that before transplanting foreign principles it is crucial to assess their workability and functionality to avoid the risk of rejection.
Knowledge Management Capabilities and Its Impact on Product Innovation in SME’s
Authors: Malkawi Mahmoud Saleh , Rumman As'ad H. Abu
Published: March 2016

Purpose–This study aims to explore the impact of Knowledge Management Capabilities (KMC), captured by six dimensions, on product innovation in Information Technology (IT) Small and Medium Enterprises (SMEs).

Design/methodology/approach– Survey data were collected from 300 managers in (45) IT SMEs located in Jordan. SPSS was employed to analyze the data.

Findings–Two key findings emerged: first, among the six dimensions of KMC, only acquisition, sharing, application, and protection were found to be positively associated with products innovation, whereas knowledge creation and storing were not. Second, no significant differences were identified in employees' answers due to company size.

Research limitations/implications – This study was restricted to small and medium size enterprises, and therefore, the findings of this study may not be generalized to large enterprises. Additionally, this study was confined to the Jordanian IT sector only, thus, the findings need to be interpreted with cautious as they may not be generalized to other sectors.

Originality/value – this study advances our understanding of the nature of the relationship between knowledge and innovation.
The Effect of International Trading Activities of Firms on Their Financial Structure
Authors: Esen Sinan , Simdi Halil , Erguzel Oylum Sehvez
Published: March 2016

This study aims to find out the impacts of international trading activities of firms on the their capital structure and profitability by using panel data analysis of the manufacturing companies listed in Istanbul Stock Exchange (ISE) for the period of 2009–2014. For this purpose we analyzed 107 manufacturing firms that declared international trade and financial data figures. We observed an inverse effect of import level on the long-term debt ratio and the negative impact of export level on the profitability. Every one-unit increase in import ratio decreases long term debt ratio by 0.0764, and every one-unit increase in export ratio decreases profitability by 0.0517. According to empirical findings there is no effect of import level on the short-term debt ratio, shareholder equity ratio and profitability. At the same time there is no effect of export level on the long term debt ratio, short term debt ratio and shareholder equity ratio.
Engaging the African Academic Diaspora: How Ready Are Universities in Africa?
Authors: Oanda Ogachi Ibrahim
Published: March 2016

While academic discussions on the negative effects of intellectual brain drain have been widely documented in the literature, the recourse to the academic diaspora as a resource to revitalise higher education institutions in Africa is recent. This recent positive consideration of the academic diaspora has largely been driven by academics in the African Diaspora, a reaction to the increased visibility of the African Diaspora generally as an economic resource to develop Africa, as attested by the African Union’s recognition of the Diaspora as its 6th region. The persisting challenges to fully benefit from diaspora intellectual resources seem to lie on the lack of clear policy and thought from the African political and university leadership to embrace this alternative more sustainably. Equally lacking are detailed studies mapping the terrain of academic cultures within universities in Africa, and the readiness of African institutions to embrace the academic diaspora. This article attempts to provide such a perspective. The article reports data from a background study in which the author participated, regarding engagements between African Diaspora academics and African universities. The data is complemented by information gleaned from policy documents of universities in East Africa, to unravel their readiness to embrace the academic diaspora in terms of their strategies. Alors que les discussions académiques sur les conséquences néfastes de la fuite des cerveaux ont été largement documentées dans la littérature, le sujet du recours à la diaspora académique pour revitaliser l’enseignement supérieur en Afrique n’est apparu que récemment. Ce sont les universitaires de la diaspora africaine qui sont à l’origine de cette vision positive de la diaspora académique, une réaction à la reconnaissance croissante de la diaspora comme ressource économique pour le développement de l’Afrique. Ceci a été notamment attesté par l’Union Africaine qui a reconnu la diaspora comme sa sixième région. Le manque de politiques claires de la part des autorités politiques et académiques pour profiter plus durablement des ressources intellectuelles de la diaspora empêche cependant de bénéficier pleinement de cette possibilité. On manque également d’études détaillées sur la culture académique des universités africaines et sur leur volonté d’inclure la diaspora académique. Cet article propose une telle perspective. Il présente les données d’une étude de fond, à laquelle l’auteur a participé, sur les interactions entre les universitaires de la diaspora africaine et les universités africaines. Ces données sont complétées par des informations glanées dans les documents stratégiques d’universités de l’est africain, pour déterminer leur volonté d’inclure la diaspora académique dans leur stratégie.
Diversity of copepods in Atlantic Patagonian coastal waters throughout an annual cycle
Authors: Spinelli Mariela L , Conçalves Rodrigo J , Villafañe Virginia E , Capitanio Fabiana L
Published: March 2016

The aim of this study is to analyze the annual zooplankton succession at a coastal station in Patagonia (Argentina), with special emphasis on copepods and their potential preys, using solar radiation and temperature as environmental factors. The annual plankton cycle exhibited autumn/winter and spring/summer phases. During the autumn/winter phase, low temperature and radiation were correlated with higher diatom abundance and copepod diversity. This period was characterized by a dominant classical herbivorous food web in which the large copepod Calanoides carinatus dominated the community. On the contrary, during the spring/summer period, with high radiation and temperature levels, flagellates were the dominant food available for zooplankton and correlated with smaller species of copepods such as the harpacticoid Euterpina acutifrons. Also, intensive reproduction of the small copepods E. acutifrons and Paracalanus parvus occurred mainly in summer. On the other hand, high species diversity was found in winter when the ultraviolet radiation was low. The temporal pattern of the copepods observed in our study was explained by food availability and environmental factors (temperature and solar radiation), although other factors such as predator abundance may also be important in modulating the community. Our results show the importance of copepod abundance dynamics and highlights their key role in the pelagic food web in northern Patagonian coastal waters.
Response of yellow catfish (Pelteobagrus fulvidraco) to different dietary concentrations of aflatoxin B1 and evaluation of an aflatoxin binder in offsetting its negative effects
Authors: Wang Xinxia , Wang Yizhen , Li Yongjin , Huang Ming , Gao Yang , Xue Xianfeng , Zhang Haiwen , Encarnação Pedro , Santos Gonçalo , Gonçalves Rui A
Published: March 2016

Aflatoxin B1 (AFB1), produced by Aspergillus flavus and Aspergillus parasiticus, is one of the major mycotoxins to affect animal health. AFB1 contamination of aquafeed is widespread, especially in countries with humid, tropical climates. The most applied method for protecting animals against aflatoxicosis is the use of clay minerals. Growth performance, immunosuppressive effects (bactericidal activity, lysozyme activity, albumin/globulin ratio, alternative complement pathway activity, and protein content), and pathology parameters were used to evaluate the response of yellow catfish (Pelteobagrus fulvidraco) to increasing concentrations of AFB1 and test the protective effect of dietary supplementation with a bentonite (dioctahedral montmorillonite) based AFB1 binder. Triplicate groups of yellow catfish with an average weight of 2.0 ± 0.1 g were fed diets containing 0, 200, 500, and 1,000 µg/kg of AFB1 alone, or diets containing 0, 200, 500, and 1,000 µg/kg of AFB1 along with 2 g/kg AFB1 binder, for 12 weeks. Results showed that diets containing increasing amounts of AFB1 had a significantly lower (P = 0.002) survival rate. There was a statistical significant reduction in weight gain, final body weight, and specific growth rate, and an increase in feed conversion ratio (FCR) influenced by the levels of AFB1 in the diet (P < 0.001 for all parameters), as well as increasing protection due to the presence of the binder (P = 0.046, P = 0.014, P = 0.038, and P = 0.485, respectively). The immunosuppressive nature of AFB1 in yellow catfish diets was confirmed through observation of lower bactericidal activity (P = 0.001), lower lysozyme activity (P = 0.006), reduced total protein (P = 0.002), and enhanced albumin/globulin ratio (P = 0.004). Fish fed diets contaminated with AFB1 and supplemented with the AFB1 binder showed better improvement in FCR (P = 0.019). These results indicate that AFB1 has a negative impact on yellow catfish growth and survival rate. The AFB1 binder protected fish from the toxic effects of AFB1.
Caught in the act: the crystal structure of cleaved cathepsin L bound to the active site of Cathepsin L
Authors: Sosnowski Piotr , Turk Dušan
Published: March 2016

Cathepsin L is a ubiquitously expressed papain‐like cysteine protease involved in the endosomal degradation of proteins and has numerous roles in physiological and pathological processes, such as arthritis, osteoporosis, and cancer. Insight into the specificity of cathepsin L is important for elucidating its physiological roles and drug discovery. To study interactions with synthetic ligands, we prepared a presumably inactive mutant and crystallized it. Unexpectedly, the crystal structure determined at 1.4 Å revealed that the cathepsin L molecule is cleaved, with the cleaved region trapped in the active site cleft of the neighboring molecule. Hence, the catalytic mutant demonstrated low levels of catalytic activity.
Server‐side workflow execution using data grid technology for reproducible analyses of data‐intensive hydrologic systems
Authors: Essawy Bakinam T. , Goodall Jonathan L. , Xu Hao , Rajasekar Arcot , Myers James D. , Kugler Tracy A. , Billah Mirza M. , Whitton Mary C. , Moore Reagan W.
Published: March 2016

Many geoscience disciplines utilize complex computational models for advancing understanding and sustainable management of Earth systems. Executing such models and their associated data preprocessing and postprocessing routines can be challenging for a number of reasons including (1) accessing and preprocessing the large volume and variety of data required by the model, (2) postprocessing large data collections generated by the model, and (3) orchestrating data processing tools, each with unique software dependencies, into workflows that can be easily reproduced and reused. To address these challenges, the work reported in this paper leverages the Workflow Structured Object functionality of the Integrated Rule‐Oriented Data System and demonstrates how it can be used to access distributed data, encapsulate hydrologic data processing as workflows, and federate with other community‐driven cyberinfrastructure systems. The approach is demonstrated for a study investigating the impact of drought on populations in the Carolinas region of the United States. The analysis leverages computational modeling along with data from the Terra Populus project and data management and publication services provided by the Sustainable Environment‐Actionable Data project. The work is part of a larger effort under the DataNet Federation Consortium project that aims to demonstrate data and computational interoperability across cyberinfrastructure developed independently by scientific communities.
Resonant near‐surface inertial oscillations in the northeastern Gulf of Mexico
Authors: Gough Matt K. , Reniers A. J. H. M. , MacMahan Jamie H. , Howden Stephan D.
Published: March 2016

The inertial frequency is nearly diurnal at 30°N latitude which transects the northeastern Gulf of Mexico (NeGoM). At this latitude, near‐surface inertial oscillations can amplify due to resonance with diurnal wind forcing. Diurnal oscillations have also been attributed to diurnal tidal forcing in this region. Because tidal forcing, wind forcing, and inertial oscillations are nearly diurnal, a unique series of comparative analyses are required to determine their relative influence on surface circulation. By comparing surface currents obtained by HF radar to predictions of the inertial response to wind forcing and barotropic tidal currents, it is found that diurnal oscillations in the NeGoM were predominantly due to wind‐forced inertial oscillations in June 2010. The analyses provide a unique spatiotemporal perspective of inertial oscillations in the NeGoM where there is evidence of propagation, frequency and phase shifts, and amplitude variability. Because inertial oscillations mix the ocean differently than the tides, these results provide insight into how inertial oscillations potentially mixed oil from the Deepwater Horizon spill in June 2010. Near‐diurnal oscillations during the winter were found to be predominantly due to tidal forcing when wind‐driven inertial oscillations were diminished due to a presumably deeper mixed layer.
Numerical experiments of the storm track sensitivity to oceanic frontal strength within the Kuroshio/Oyashio Extensions
Authors: Yao Yao , Zhong Zhong , Yang Xiu‐Qun
Published: March 2016

The sensitivity of the North Pacific storm track to midlatitude oceanic frontal strength within the Kuroshio/Oyashio Extensions is investigated by applying artificially changed meridional sea surface temperature (SST) gradients in the Weather Research Forecasting model version 3.4. The result of sensitivity experiments further confirms the close relationship between the storm track activity and meridional SST gradient; i.e., the storm track activity can be intensified as a response to increases in the oceanic frontal strength. In order to better understand the mechanism for the storm track intensification due to increased SST gradient, velocity‐temperature correlation and local energetics are analyzed. The result indicates that the enhancement of the meridional SST gradient leads to amplitude magnification of eddy meridional velocity and temperature and their phase consistency, suggesting that synoptic‐scale eddies tend to approach the optimum structure for the baroclinic energy conversion, which is mainly responsible for the SST front‐induced enhancement of storm track activity. In order to estimate the impact of the oceanic front on the maintenance of the near‐surface baroclinicity, further investigation is made by the composite analysis. With the increase in oceanic frontal strength, the near‐surface baroclinicity experiences a slow but strong restoration. The increase in the meridional SST gradient results in the intensification in the cross‐frontal differential sensible heat flux, which can more effectively offset the relaxing effect of the transient eddy poleward heat transport.
Polarimetric radar and aircraft observations of saggy bright bands during MC3E
Authors: Kumjian Matthew R. , Mishra Subashree , Giangrande Scott E. , Toto Tami , Ryzhkov Alexander V. , Bansemer Aaron
Published: March 2016

Polarimetric radar observations increasingly are used to understand cloud microphysical processes, which is critical for improving their representation in cloud and climate models. In particular, there has been recent focus on improving representations of ice collection processes (e.g., aggregation and riming), as these influence precipitation rate, heating profiles, and ultimately cloud life cycles. However, distinguishing these processes using conventional polarimetric radar observations is difficult, as they produce similar fingerprints. This necessitates improved analysis techniques and integration of complementary data sources. The Midlatitude Continental Convective Clouds Experiment (MC3E) provided such an opportunity. Quasi‐vertical profiles of polarimetric radar variables in two MC3E stratiform precipitation events reveal episodic melting layer sagging. Integrated analyses using scanning and vertically pointing radar and aircraft measurements reveal that saggy bright band signatures are produced when denser, faster‐falling, more isometric hydrometeors (relative to adjacent times) descend into the melting layer. In one case, strong circumstantial evidence for riming is found during bright band sagging times. A bin microphysical melting layer model successfully reproduces many aspects of the signature, supporting the observational analysis. If found to be a reliable indicator of riming, saggy bright bands could be a proxy for the presence of supercooled liquid water in stratiform precipitation, which may provide important information for mitigating aircraft icing risks and for constraining microphysical models.
Watershed model calibration to the base flow recession curve with and without evapotranspiration effects
Authors: Jepsen S. M. , Harmon T. C. , Shi Y.
Published: March 2016

Calibration of watershed models to the shape of the base flow recession curve is a way to capture the important relationship between groundwater discharge and subsurface water storage in a catchment. In some montane Mediterranean regions, such as the midelevation Providence Creek catchment in the southern Sierra Nevada of California (USA), nearly all base flow recession occurs after snowmelt, and during this time evapotranspiration (ET) usually exceeds base flow. We assess the accuracy to which watershed models can be calibrated to ET‐dominated base flow recession in Providence Creek, both in terms of fitting a discharge time‐series and realistically capturing the observed discharge‐storage relationship for the catchment. Model parameters estimated from calibrations to ET‐dominated recession are compared to parameters estimated from reference calibrations to base flow recession with ET‐effects removed (“potential recession”). We employ the Penn State Integrated Hydrologic Model (PIHM) for simulations of base flow and ET, and methods that are otherwise general in nature. In models calibrated to ET‐dominated recession, simulation errors in ET and the targeted relationship for recession (−dQ/dt versus Q) contribute substantially (up to 57% and 46%, respectively) to overestimates in the discharge‐storage differential, defined as d(lnQ)/dS, relative to that derived from water flux observations. These errors result in overestimates of deep‐subsurface hydraulic conductivity in models calibrated to ET‐dominated recession, by up to an order of magnitude, relative to reference calibrations to potential recession. These results illustrate a potential opportunity for improving model representation of discharge‐storage dynamics by calibrating to the shape of base flow recession after removing the complicating effects of ET.
Combining information from multiple flood projections in a hierarchical Bayesian framework
Authors: Le Vine Nataliya
Published: March 2016

This study demonstrates, in the context of flood frequency analysis, the potential of a recently proposed hierarchical Bayesian approach to combine information from multiple models. The approach explicitly accommodates shared multimodel discrepancy as well as the probabilistic nature of the flood estimates, and treats the available models as a sample from a hypothetical complete (but unobserved) set of models. The methodology is applied to flood estimates from multiple hydrological projections (the Future Flows Hydrology data set) for 135 catchments in the UK. The advantages of the approach are shown to be: (1) to ensure adequate “baseline” with which to compare future changes; (2) to reduce flood estimate uncertainty; (3) to maximize use of statistical information in circumstances where multiple weak predictions individually lack power, but collectively provide meaningful information; (4) to diminish the importance of model consistency when model biases are large; and (5) to explicitly consider the influence of the (model performance) stationarity assumption. Moreover, the analysis indicates that reducing shared model discrepancy is the key to further reduction of uncertainty in the flood frequency analysis. The findings are of value regarding how conclusions about changing exposure to flooding are drawn, and to flood frequency change attribution studies.
Toward improved prediction of the bedrock depth underneath hillslopes: Bayesian inference of the bottom‐up control hypothesis using high‐resolution topographic data
Authors: Gomes Guilherme J. C. , Vrugt Jasper A. , Vargas Eurípedes A.
Published: March 2016

The depth to bedrock controls a myriad of processes by influencing subsurface flow paths, erosion rates, soil moisture, and water uptake by plant roots. As hillslope interiors are very difficult and costly to illuminate and access, the topography of the bedrock surface is largely unknown. This essay is concerned with the prediction of spatial patterns in the depth to bedrock (DTB) using high‐resolution topographic data, numerical modeling, and Bayesian analysis. Our DTB model builds on the bottom‐up control on fresh‐bedrock topography hypothesis of Rempe and Dietrich (2014) and includes a mass movement and bedrock‐valley morphology term to extent the usefulness and general applicability of the model. We reconcile the DTB model with field observations using Bayesian analysis with the DREAM algorithm. We investigate explicitly the benefits of using spatially distributed parameter values to account implicitly, and in a relatively simple way, for rock mass heterogeneities that are very difficult, if not impossible, to characterize adequately in the field. We illustrate our method using an artificial data set of bedrock depth observations and then evaluate our DTB model with real‐world data collected at the Papagaio river basin in Rio de Janeiro, Brazil. Our results demonstrate that the DTB model predicts accurately the observed bedrock depth data. The posterior mean DTB simulation is shown to be in good agreement with the measured data. The posterior prediction uncertainty of the DTB model can be propagated forward through hydromechanical models to derive probabilistic estimates of factors of safety.
A laboratory study to estimate pore geometric parameters of sandstones using complex conductivity and nuclear magnetic resonance for permeability prediction
Authors: Osterman Gordon , Keating Kristina , Binley Andrew , Slater Lee
Published: March 2016

We estimate parameters from the Katz and Thompson permeability model using laboratory complex electrical conductivity (CC) and nuclear magnetic resonance (NMR) data to build permeability models parameterized with geophysical measurements. We use the Katz and Thompson model based on the characteristic hydraulic length scale, determined from mercury injection capillary pressure estimates of pore throat size, and the intrinsic formation factor, determined from multisalinity conductivity measurements, for this purpose. Two new permeability models are tested, one based on CC data and another that incorporates CC and NMR data. From measurements made on forty‐five sandstone cores collected from fifteen different formations, we evaluate how well the CC relaxation time and the NMR transverse relaxation times compare to the characteristic hydraulic length scale and how well the formation factor estimated from CC parameters compares to the intrinsic formation factor. We find: (1) the NMR transverse relaxation time models the characteristic hydraulic length scale more accurately than the CC relaxation time (
of 0.69 and 0.33 and normalized root mean square errors (NRMSE) of 0.16 and 0.21, respectively); (2) the CC estimated formation factor is well correlated with the intrinsic formation factor (NRMSE=0.23). We demonstrate that that permeability estimates from the joint‐NMR‐CC model (NRMSE=0.13) compare favorably to estimates from the Katz and Thompson model (NRMSE=0.074). This model advances the capability of the Katz and Thompson model by employing parameters measureable in the field giving it the potential to more accurately estimate permeability using geophysical measurements than are currently possible.
Weathering resistance of carbonate fault mirrors promotes rupture localization
Authors: Goldberg R. , Siman‐Tov S. , Emmanuel S.
Published: March 2016

Fractured rocks in fault zones regain their mechanical strength through a process called healing. A central pathway for healing involves the dissolution and reprecipitation of minerals in the fault zone which cements the fractured rocks during interseismic periods. However, some faults contain highly polished surfaces—coated in a thin nanoparticle layer—along which slip is localized. Crucially, these surfaces show little evidence of postseismic mineralization and healing. Here we use atomic force microscopy to show that naturally polished rocks from carbonate fault zones are resistant to dissolution, in stark contrast to the reactive minerals that make up the fault breccia. Our results suggest that the low reactivity of the nanoparticle layer could retard healing, helping to maintain the localization of the fault zone between seismic slip events. As fault localization affects seismic motion, the geochemical reactivity of fault mirrors could be an important control on seismicity along faults.
Electromagnetic disturbances observed near the dip region ahead of dipolarization front
Authors: Zhao D. , Fu S. Y. , Sun W. J. , Parks G. K. , Zong Q. G. , Shi Q. Q. , Pu Z. Y. , Cui Y. B. , Wu T. , Liu J. , Zhou X. Z.
Published: March 2016

Dipolarization front (DF) is a thin magnetic structure embedded in fast flows in the magnetotail, which plays an important role in particle acceleration, flow braking, wave excitation, and other related processes. Electromagnetic disturbances near the magnetic dip region in front of DFs are investigated using Time History of Events and Macroscale Interactions during Substorms probe observations in this paper. Strong magnetic field and electric field fluctuations, with several wave bands below and around the lower hybrid frequency, are found in an event on 21 March 2008. The properties of the wave are similar to that of magnetosonic wave. Detailed analyses show that the phase space density for ions in the perpendicular direction has a positive slope near the local Alfvén speed, which is a possible free‐energy source for the generation of the wave. This type of ion distribution could result from the earthward reflected ions ahead of DF, though other forming mechanism could not be fully ruled out.
Polar cap patches and the tongue of ionization: A survey of GPS TEC maps from 2009 to 2015
Authors: David Michael , Sojka J. J. , Schunk R. W. , Coster A. J.
Published: March 2016

The source and structuring mechanisms for F region density patches have been subjects of speculation and debate for many years. We have made a survey of mappings of total electron content (TEC) between the years 2009 and 2015 from the web‐based Madrigal data server in order to determine when patches and/or a tongue of ionization (TOI) have been present in the Northern Hemisphere polar cap; we find that there is a UT and seasonal dependence that follows a specific pattern. This finding sheds considerable light upon the old question of the source of polar cap patches, since it virtually eliminates potential patch plasma sources that do not have a UT/seasonal dependence, for example, particle precipitation or flux transfer events. We also find that the frequency of occurrence of patches or TOIs has little to do with the level of geomagnetic activity.