bluuebunny/crossref_metadata_2025 huggingface dataset:
Reasoning about actions with sensing under qualitative and probabilistic uncertainty
Authors: Iocchi Luca , Lukasiewicz Thomas , Nardi Daniele , Rosati Riccardo
Published: January 2009

We focus on the aspect of sensing in reasoning about actions under qualitative and probabilistic uncertainty. We first define the action language
E
for reasoning about actions with sensing, which has a semantics based on the autoepistemic description logic

ALCK
NF

, and which is given a formal semantics via a system of deterministic transitions between epistemic states. As an important feature, the main computational tasks in
E
can be done in linear and quadratic time. We then introduce the action language
E
+ for reasoning about actions with sensing under qualitative and probabilistic uncertainty, which is an extension of
E
by actions with nondeterministic and probabilistic effects, and which is given a formal semantics in a system of deterministic, nondeterministic, and probabilistic transitions between epistemic states. We also define the notion of a belief graph, which represents the belief state of an agent after a sequence of deterministic, nondeterministic, and probabilistic actions, and which compactly represents a set of unnormalized probability distributions. Using belief graphs, we then introduce the notion of a conditional plan and its goodness for reasoning about actions under qualitative and probabilistic uncertainty. We formulate the problems of optimal and threshold conditional planning under qualitative and probabilistic uncertainty, and show that they are both uncomputable in general. We then give two algorithms for conditional planning in our framework. The first one is always sound, and it is also complete for the special case in which the relevant transitions between epistemic states are cycle-free. The second algorithm is a sound and complete solution to the problem of finite-horizon conditional planning in our framework. Under suitable assumptions, it computes every optimal finite-horizon conditional plan in polynomial time. We also describe an application of our formalism in a robotic-soccer scenario, which underlines its usefulness in realistic applications.
A logical characterization of the counting hierarchy
Authors: Kontinen Juha
Published: January 2009

In this article we give a logical characterization of the counting hierarchy. The counting hierarchy is the analogue of the polynomial hierarchy, the building block being Probabilistic polynomial time PP instead of NP. We show that the extension of first-order logic by second-order majority quantifiers of all arities describes exactly the problems in the counting hierarchy. We also consider extending the characterization to general proportional quantifiersQkrinterpreted as “more than anr-fraction ofk-ary relations”. We show that the result holds for rational numbers of the forms/2mbut for any other 0 <r< 1 the corresponding logic satisfies the 0-1 law.
FPGA Acceleration of RankBoost in Web Search Engines
Authors: Xu Ning-Yi , Cai Xiong-Fei , Gao Rui , Zhang Lei , Hsu Feng-Hsiung
Published: January 2009

Search relevance is a key measurement for the usefulness of search engines. Shift of search relevance among search engines can easily change a search company's market cap by tens of billions of dollars. With the ever-increasing scale of the Web, machine learning technologies have become important tools to improve search relevance ranking. RankBoost is a promising algorithm in this area, but it is not widely used due to its long training time. To reduce the computation time for RankBoost, we designed a FPGA-based accelerator system and its upgraded version. The accelerator, plugged into a commodity PC, increased the training speed on MSN search engine data up to 1800x compared to the original software implementation on a server. The proposed accelerator has been successfully used by researchers in the search relevance ranking.
Exploiting Partial Runtime Reconfiguration for High-Performance Reconfigurable Computing
Authors: El-Araby Esam , Gonzalez Ivan , El-Ghazawi Tarek
Published: January 2009

Runtime Reconfiguration (RTR) has been traditionally utilized as a means for exploiting the flexibility of High-Performance Reconfigurable Computers (HPRCs). However, the RTR feature comes with the cost of high configuration overhead which might negatively impact the overall performance. Currently, modern FPGAs have more advanced mechanisms for reducing the configuration overheads, particularly Partial Runtime Reconfiguration (PRTR). It has been perceived that PRTR on HPRC systems can be the trend for improving the performance. In this work, we will investigate the potential of PRTR on HPRC by formally analyzing the execution model and experimentally verifying our analytical findings by enabling PRTR for the first time, to the best of our knowledge, on one of the current HPRC systems, Cray XD1. Our approach is general and can be applied to any of the available HPRC systems. The paper will conclude with recommendations and conditions, based on our conceptual and experimental work, for the optimal utilization of PRTR as well as possible future usage in HPRC.
Synthesis and Optimization of 2D Filter Designs for Heterogeneous FPGAs
Authors: Bouganis Christos-S. , Park Sung-Boem , Constantinides George A. , Cheung Peter Y. K.
Published: January 2009

Many image processing applications require fast convolution of an image with one or more 2D filters. Field-Programmable Gate Arrays (FPGAs) are often used to achieve this goal due to their fine grain parallelism and reconfigurability. However, the heterogeneous nature of modern reconfigurable devices is not usually considered during design optimization. This article proposes an algorithm that explores the space of possible implementation architectures of 2D filters, targeting the minimization of the required area, by optimizing the usage of the different components in a heterogeneous device. This is achieved by exploring the heterogeneous nature of modern reconfigurable devices using a Singular Value Decomposition based algorithm, which provides an efficient mapping of filter's implementation requirements to the heterogeneous components of modern FPGAs. In the case of multiple 2D filters, the proposed algorithm also exploits any redundancy that exists within each filter and between different filters in the set, leading to designs with minimized area. Experiments with real filter sets from computer vision applications demonstrate an average of up to 38% reduction in the required area.
Coordinating government funding of file system and I/O research through the high end computing university research activity
Authors: Grider Gary , Nunez James , Bent John , Poole Steve , Ross Rob , Felix Evan
Published: January 2009

In 2003, the High End Computing Revitalization Task Force designated file systems and I/O as an area in need of national focus. The purpose of the High End Computing Interagency Working Group (HECIWG) is to coordinate government spending on File Systems and I/O (FSIO) R&D by all the government agencies that are involved in High End Computing. The HECIWG tasked a smaller advisory group to list, categorize, and prioritize HEC I/O and File Systems R&D needs. In 2005, leaders in FSIO from academia, industry and government agencies collaborated to list and prioritize areas of research in HEC FSIO. This led to a very successful High End Computing University Research Activity (HECURA) call from NSF in 2006 and has prompted a new HECURA call from NSF in 2009. This paper serves as both a review of the 2008 HEC FSIO identified research gaps as well as a preview of this forthcoming HECURA call.
Providing secure services for a virtual infrastructure
Authors: Baldwin Adrian , Dalton Chris , Shiu Simon , Kostienko Krzysztof , Rajpoot Qasim
Published: January 2009

Virtualization brings exibility to the data center and enables separations allowing for better security properties. For these security properties to be fully utilized, virtual machines need to be able to connect to secure services such as networking and storage. This paper addresses the problems associated with managing the cryptographic keys upon which such services rely by ensuring that keys remain within the trusted computing base. Here we describe a general architecture for managing keys tied to the underlying virtualized systems, with a specific example given for secure storage.
The Impact of Seller Reputation on the Performance of online sales
Authors: Ye Qiang , Li Yijun , Kiang Melody , Wu Weifang
Published: January 2009

The understanding of the seller reputation and sales performance relationship is an important topic in C2C market. Previous research has mainly focused on the C2C market in the U.S. The findings of that research have not been validated in countries with different cultural backgrounds such as China. With the explosive growth of electronic markets in China, the study of C2C online sales becomes increasingly important. This paper attempts to understand seller reputation effects on sales price, number of sales, and total revenue, based on But-It-Now (BIN) data collected from TaoBao.com, the largest online auction site in China. Multiple regression analysis is performed to test the significance of the effects. This study revealed cross effects of negative ratings on the performance of a seller. By separating the cross effects of magnitude and reputation of negative ratings, this study demonstrated that positive ratings have a significant positive impact on the performance of sellers, while negative ratings have negative reputation effects and positive magnitude effects. This is the first study that has focused on understanding the Buy-It-Now pricing and seller reputation relationship. Since the BIN feature is the most popular way of selling in online C2C markets in China, we believe the findings of this research will provide insight to researchers performing cross-cultural comparisosn between China and other markets.
Green tea (−)-epigallocatechin gallate inhibits insulin stimulation of 3T3-L1 preadipocyte mitogenesis via the 67-kDa laminin receptor pathway
Authors: Ku Hui-Chen , Chang Hsin-Huei , Liu Hsien-Chun , Hsiao Chiao-Hsin , Lee Meng-Jung , Hu Yu-Jung , Hung Pei-Fang , Liu Chi-Wei , Kao Yung-Hsi
Published: January 2009

Insulin and (−)-epigallocatechin gallate (EGCG) have been reported to regulate fat cell mitogenesis and adipogenesis, respectively. This study investigated the pathways involved in EGCG modulation of insulin-stimulated mitogenesis in 3T3-L1 preadipocytes. EGCG inhibited insulin stimulation of preadipocyte proliferation in a dose- and time-dependent manner. EGCG also suppressed insulin-stimulated phosphorylation of the insulin receptor-β, insulin receptor (IR) substrates 1 and 2 (IRS1 and IRS2), and mitogen-activated protein kinase pathway proteins, RAF1, MEK1/2, and ERK1/2, but not JNK. Furthermore, EGCG inhibited the association of IR with the IRS1 and IRS2 proteins, but not with the IRS4 protein. These data suggest that EGCG selectively affects particular types of IRS and MAPK family members. Generally, EGCG was more effective than epicatechin, epicatechin gallate, and epigallocatechin in modulating insulin-stimulated mitogenic signaling. We identified the EGCG receptor [also known as the 67-kDa laminin receptor (67LR)] in fat cells and found that its expression was sensitive to growth phase, tissue type, and differentiation state. Pretreatment of preadipocytes with 67LR antiserum prevented the effects of EGCG on insulin-stimulated phosphorylation of IRS2, RAF1, and ERK1/2 and insulin-stimulated preadipocyte proliferation (cell number and bromodeoxyuridine incorporation). Moreover, EGCG tended to increase insulin-stimulated associations between the 67LR and IR, IRS1, IRS2, and IRS4 proteins. These data suggest that EGCG mediates anti-insulin signaling in preadipocyte mitogenesis via the 67LR pathway.
The role of cell cholesterol and the cytoskeleton in the interaction between IK1 and maxi-K channels
Authors: Romanenko Victor G. , Roser Kurt S. , Melvin James E. , Begenisich Ted
Published: January 2009

Recently, we demonstrated a novel interaction between large-conductance (maxi-K or KCa1.1) and intermediate-conductance (IK1 or KCa3.1) Ca2+-activated K channels: activation of IK1 channels causes the inhibition of maxi-K activity (Thompson J and Begenisich T. J Gen Physiol 127: 159–169, 2006). Here we show that the interaction between these two channels can be regulated by the membrane cholesterol level in parotid acinar cells. Depletion of cholesterol using methyl-β-cyclodextrin weakened, while cholesterol enrichment increased, the ability of IK1 activation to inhibit maxi-K channels. Cholesterol's stereoisomer, epicholesterol, was unable to substitute for cholesterol in the interaction between the two K channels, suggesting a specific cholesterol-protein interaction. This suggestion was strengthened by the results of experiments in which cholesterol was replaced by coprostanol and epicoprostanol. These two sterols have nearly identical effects on membrane physical properties and cholesterol-rich microdomain stability, but had very different effects on the IK1/maxi-K interaction. In addition, the IK1/maxi-K interaction was unaltered in cells lacking caveolin, the protein essential for formation and stability of caveolae. Finally, disruption of the actin cytoskeleton restored the IK1-induced maxi-K inhibition that was lost with cell cholesterol depletion, demonstrating the importance of an intact cytoskeleton for the cholesterol-dependent regulation of the IK1/maxi-K interaction.
Counterregulation of clathrin-mediated endocytosis by the actin and microtubular cytoskeleton in human neutrophils
Authors: Uriarte Silvia M. , Jog Neelakshi R. , Luerman Gregory C. , Bhimani Samrath , Ward Richard A. , McLeish Kenneth R.
Published: January 2009

We have recently reported that disruption of the actin cytoskeleton enhanced N-formylmethionyl-leucyl-phenylalanine (fMLP)-stimulated granule exocytosis in human neutrophils but decreased plasma membrane expression of complement receptor 1 (CR1), a marker of secretory vesicles. The present study was initiated to determine if reduced CR1 expression was due to fMLP-stimulated endocytosis, to determine the mechanism of this endocytosis, and to examine its impact on neutrophil functional responses. Stimulation of neutrophils with fMLP or ionomycin in the presence of latrunculin A resulted in the uptake of Alexa fluor 488-labeled albumin and transferrin and reduced plasma membrane expression of CR1. These effects were prevented by preincubation of the cells with sucrose, chlorpromazine, or monodansylcadaverine (MDC), inhibitors of clathrin-mediated endocytosis. Sucrose, chlorpromazine, and MDC also significantly inhibited fMLP- and ionomycin-stimulated specific and azurophil granule exocytosis. Disruption of microtubules with nocodazole inhibited endocytosis and azurophil granule exocytosis stimulated by fMLP in the presence of latrunculin A. Pharmacological inhibition of phosphatidylinositol 3-kinase, ERK1/2, and PKC significantly reduced fMLP-stimulated transferrin uptake in the presence of latrunculin A. Blockade of clathrin-mediated endocytosis had no significant effect on fMLP-stimulated phosphorylation of ERK1/2 in neutrophils pretreated with latrunculin A. From these data, we conclude that the actin cytoskeleton functions to limit microtubule-dependent, clathrin-mediated endocytosis in stimulated human neutrophils. The limitation of clathrin-mediated endocytosis by actin regulates the extent of both specific and azurophilic granule exocytosis.
Vascular endothelial growth factor induces protein kinase D-dependent production of proinflammatory cytokines in endothelial cells
Authors: Hao Qin , Wang Linping , Tang Hua
Published: January 2009

Emerging evidence indicates that vascular endothelial growth factor (VEGF) plays a critical role in host inflammatory responses in several disease states, including atherosclerosis, sepsis, and rheumatoid arthritis. In this study, we determined the effect of VEGF on endothelial induction of proinflammatory cytokines and investigated the responsible signal pathways. By using a cytokine antibody array that detects the end point protein products released from endothelial cells (ECs), we found that VEGF, via VEGF receptor 2 (VEGFR2), predominantly induced the production of proinflammatory cytokine interleukin (IL)-6 and CXC chemokines IL-8 and growth-related oncogene-α (GRO-α) in ECs but not in leukocytes among 36 cytokines in the array. The production of these inflammatory cytokines by VEGF was much stronger than the induction of cell adhesion molecule in ECs. We further found that the cytokine production by VEGF was essentially mediated by the Gö-6976-sensitive protein kinase D (PKD) family kinases. Importantly, the VEGF-induced production of IL-6, IL-8, and GRO-α was inhibited ∼70%, 40%, or 37% by PKD1 silencing (more than 90% knockdown) with three small interference RNAs that target different PKD1 regions. Moreover, silencing PKD2 downregulated VEGFR2 and markedly inhibited the cytokine production by VEGF in ECs. Our results indicate that VEGF, via VEGFR2-PKD1 axis, induces the production of proinflammatory cytokine IL-6, IL-8, and GRO-α in ECs but not in leukocytes, which may offer new insights into the mechanism of the proinflammatory activity of VEGF.
Polyamines regulate E-cadherin transcription through c-Myc modulating intestinal epithelial barrier function
Authors: Liu Lan , Guo Xin , Rao Jaladanki N. , Zou Tongtong , Xiao Lan , Yu Tingxi , Timmons Jennifer A. , Turner Douglas J. , Wang Jian-Ying
Published: January 2009

The integrity of the intestinal epithelial barrier depends on intercellular junctions that are highly regulated by numerous extracellular and intracellular factors. E-cadherin is found primarily at the adherens junctions in the intestinal mucosa and mediates strong cell-cell contacts that have a functional role in forming and regulating the epithelial barrier. Polyamines are necessary for E-cadherin expression, but the exact mechanism underlying polyamines remains elusive. The current study was performed to determine whether polyamines induce E-cadherin expression through the transcription factor c-Myc and whether polyamine-regulated E-cadherin plays a role in maintenance of the epithelial barrier integrity. Decreasing cellular polyamines reduced c-Myc and repressed E-cadherin transcription as indicated by a decrease in levels of E-cadherin promoter activity and its mRNA. Forced expression of the c- myc gene by infection with adenoviral vector containing c-Myc cDNA stimulated E-cadherin promoter activity and increased E-cadherin mRNA and protein levels in polyamine-deficient cells. Experiments using different E-cadherin promoter mutants revealed that induction of E-cadherin transcription by c-Myc was mediated through the E-Pal box located at the proximal region of the E-cadherin promoter. Decreased levels of E-cadherin in polyamine-deficient cells marginally increased basal levels of paracellular permeability but, remarkably, potentiated H2O2-induced epithelial barrier dysfunction. E-cadherin silencing by transfection with its specific small interfering RNA also increased vulnerability of the epithelial barrier to H2O2. These results indicate that polyamines enhance E-cadherin transcription by activating c-Myc, thus promoting function of the epithelial barrier.
Glycemic control prevents microvascular remodeling and increased tone in Type 2 diabetes: link to endothelin-1
Authors: Sachidanandam Kamakshi , Hutchinson Jim R. , Elgebaly Mostafa M. , Mezzetti Erin M. , Dorrance Anne M. , Motamed Kouros , Ergul Adviye
Published: January 2009

Medial thickening and vascular hypertrophy of resistance arteries can lead to cardiovascular complications associated with diabetes. While previous studies have established a role of Type 1 diabetes in vascular remodeling, we recently extended these observations to Type 2 diabetes and reported increased collagen deposition due to alterations in matrix metalloproteinase expression and activity in mesenteric resistance arteries. These studies also showed that remodeling response was mediated by endothelin-1 (ET-1) via activation of ETA receptors, whereas blockade of ETB receptors exacerbated the remodeling. However, the effectiveness of glycemic control strategies in preventing these vascular changes, including activation of the ET system still remained unclear. Also, very little is known about whether and to what extent reorganization of the extracellular matrix (ECM) affects vascular compliance and vasomotor tone. Accordingly, this study assessed structural remodeling of mesenteric microvessels, vascular compliance, and myogenic tone, as well as the role of matrix metalloproteinases (MMP) in mediating these processes. Spontaneously diabetic, non-obese Goto-Kakizaki (GK) rats, a model for Type 2 diabetes, and normoglycemic Wistar rats were used for the studies. A subset of GK rats were administered metformin to achieve euglycemia. Glycemic control normalized the increased media-to-lumen ratios (M/L) and myogenic tone seen in diabetes, as well as normalizing plasma ET-1 levels and mesenteric ETA receptor expression. There was increased collagen synthesis in diabetes paralleled by decreased collagenase MMP-13 activity, while glycemic control attenuated the process. These findings and our previous study taken together suggest that hyperglycemia-mediated activation of ET-1 and ETA receptors alter vascular structure and mechanics in Type 2 diabetes.
The role of venous capacitance, circulating catecholamines, and heart rate in the hemodynamic response to increased temperature and hypoxia in the dogfish
Authors: Sandblom Erik , Cox Georgina K. , Perry Steve F. , Farrell Anthony P.
Published: January 2009

Hypoxia and increased temperature alter venous blood pressures in teleosts through active changes in venous tone. Elasmobranchs possess a capacious venous system but have limited adrenergic vascular innervation and subambient central venous pressure (Pcv). In this study, we explored venous hemodynamic responses to acute temperature increase and moderate (6.9 kPa) and severe (2.5 kPa) hypoxia in the dogfish ( Squalus acanthias). Normoxic dogfish at 10°C had a Pcvbetween −0.08 and −0.04 kPa and a mean circulatory filling pressure (Pmcf) of ∼0.12 kPa. At 16°C, heart rate ( fH), cardiac output (Q), and Pmcfincreased but Pcvand plasma epinephrine and norepinephrine levels were unchanged. In contrast, moderate and severe hypoxia increased Pcvand decreased Q and stroke volume (VS). fHdecreased in severe hypoxia, whereas Pmcfwas unaffected despite elevated catecholamine levels. Atropine abolished hypoxic reductions in Q, VS, and fH, but Pcvstill increased. In contrast to the response in teleosts, this study on dogfish suggests that venous capacitance changes associated with warming and hypoxia are minimal and likely not mediated by circulating catecholamines. Thus hemodynamic status of the capacious elasmobranch venous circulation is potentially regulated by blood volume shifts from passive flow-mediated events and possibly through myogenic mechanisms.
Postnatal developmental renal physiology: a study of historic significance
Authors: Baum Michel
Published: January 2009

This essay looks at the historic significance of an APS classic paper ( http://www.the-aps.org/publications/classics/ ) that is freely available online:

Falk G. Maturation of renal function in infant rats. Am J Physiol 181: 157–170, 1955 ( http://ajplegacy.physiology.org/cgi/reprint/181/1/157 ).
The cardiotonic steroid hormone marinobufagenin induces renal fibrosis: implication of epithelial-to-mesenchymal transition
Authors: Fedorova Larisa V. , Raju Vanamala , El-Okdi Nasser , Shidyak Amjad , Kennedy David J. , Vetteth Sandeep , Giovannucci David R. , Bagrov Alexei Y. , Fedorova Olga V. , Shapiro Joseph I. , Malhotra Deepak
Published: January 2009

We recently demonstrated that the cardiotonic steroid marinobufagenin (MBG) induced fibrosis in rat hearts through direct stimulation of collagen I secretion by cardiac fibroblasts. This stimulation was also responsible for the cardiac fibrosis seen in experimental renal failure. In this study, the effect of MBG on the development of renal fibrosis in rats was investigated. Four weeks of MBG infusion triggered mild periglomerular and peritubular fibrosis in the cortex and the appearance of fibrotic scars in the corticomedullary junction of the kidney. MBG also significantly increased the protein levels and nuclear localization of the transcription factor Snail in the tubular epithelia. It is known that activation of Snail is associated with epithelial-to-mesenchymal transition (EMT) during renal fibrosis. To examine whether MBG alone can trigger EMT, we used the porcine proximal tubular cell line LLC-PK1. MBG (100 nM) caused LLC-PK1 cells grown to confluence to acquire a fibroblast-like shape and have an invasive motility. The expressions of the mesenchymal proteins collagen I, fibronectin, and vimentin were increased twofold. However, the total level of E-cadherin remained unchanged. These alterations in LLC-PK1 cells in the presence of MBG were accompanied by elevated expression and nuclear translocation of Snail. During the time course of EMT, MBG did not have measurable inhibitory effects on the ion pumping activity of its natural ligand, Na+-K+-ATPase. Our data suggest that the MBG may be an important factor in inducing EMT and, through this mechanism, elevated levels of MBG in chronic renal failure may play a role in the progressive fibrosis.
Right coronary artery becomes stiffer with increase in elastin and collagen in right ventricular hypertrophy
Authors: Garcia Marisa , Kassab Ghassan S.
Published: January 2009

Changes in blood flow influence the structure, function, mechanical properties, and remodeling of arteries. The objective of the present study was to investigate the role of increased blood flow on the biaxial incremental elastic moduli of the porcine right coronary artery (RCA) and to determine the microstructural basis for the changes in moduli. We hypothesized that an increase in RCA flow will lead to increased stiffness in conjunction with remodeling of elastin and collagen in the vessel wall. The control and experimental groups consisted of five RCA vessels each. The RCA of the experimental group was exposed to 4 wk of flow-overload in right ventricular hypertrophy induced by pulmonary artery banding. Stress-strain relationships were determined and the incremental elastic moduli were derived in the circumferential, axial, and cross directions. The results show a significant increase in the elastic moduli in the circumferential (262.7 ± 15.7 vs. 120.2 ± 12.4 kPa; P < 0.001), axial (177.8 ± 25.5 vs. 100.3 ± 11.9 kPa; P = 0.025), and cross directions (104.8 ± 8.2 vs. 68.2 ± 8.6 kPa; P = 0.016) of the experimental RCA compared with controls. Multiphoton microscopy was used to assess the changes in elastin and collagen content in the media and adventitia of the vessel wall. We found a significant increase in elastin and collagen area fraction particularly in the adventitial layer. These data suggest stiffening of the vessel wall as a result of increased elastin and more predominantly collagen.
Neural Basis of the Set-Size Effect in Frontal Eye Field: Timing of Attention During Visual Search
Authors: Cohen Jeremiah Y. , Heitz Richard P. , Woodman Geoffrey F. , Schall Jeffrey D.
Published: January 2009

Visual search for a target object among distractors often takes longer when more distractors are present. To understand the neural basis of this capacity limitation, we recorded activity from visually responsive neurons in the frontal eye field (FEF) of macaque monkeys searching for a target among distractors defined by form (randomly oriented T or L). To test the hypothesis that the delay of response time with increasing number of distractors originates in the delay of attention allocation by FEF neurons, we manipulated the number of distractors presented with the search target. When monkeys were presented with more distractors, visual target selection was delayed and neuronal activity was reduced in proportion to longer response time. These findings indicate that the time taken by FEF neurons to select the target contributes to the variation in visual search efficiency.
Functional Consequences of Neuronal Divergence Within the Retinogeniculate Pathway
Authors: Yeh Chun-I , Stoelzel Carl R. , Weng Chong , Alonso Jose-Manuel
Published: January 2009

The neuronal connections from the retina to the dorsal lateral geniculate nucleus (dLGN) are characterized by a high specificity. Each retinal ganglion cell diverges to connect to a small group of geniculate cells and each geniculate cell receives input from a small number of retinal ganglion cells. Consistent with the high specificity of the connections, geniculate cells sharing input from the same retinal afferent are thought to have very similar receptive fields. However, the magnitude of the receptive-field mismatches, which has not been systematically measured across the different cell types in dLGN, seems to be in contradiction with the functional anatomy of the Y visual pathway: Y retinal afferents in the cat diverge into two geniculate layers (A and C) that have Y geniculate cells (YAand YC) with different receptive-field sizes, response latencies, nonlinearity of spatial summation, and contrast sensitivity. To better understand the functional consequences of retinogeniculate divergence, we recorded from pairs of geniculate cells that shared input from a common retinal afferent across layers and within the same layer in dLGN. We found that nearly all cell pairs that shared retinal input across layers had Y-type receptive fields of the same sign (i.e., both on-center) that overlapped by >70%, but frequently differed in size and response latency. The receptive-field mismatches were relatively small in value (receptive-field size ratio <5; difference in peak response <5 ms), but were robustly correlated with the strength of the synchronous firing generated by the shared retinal connections ( R2= 0.75). On average, the percentage of geniculate spikes that could be attributed to shared retinal inputs was about 10% for all cell-pair combinations studied. These results are used to provide new estimates of retinogeniculate divergence for different cell classes.
Distinct Roles of Metabotropic Glutamate Receptor Activation on Inhibitory Signaling in the Ventral Lateral Geniculate Nucleus
Authors: Govindaiah G. , Cox Charles L.
Published: January 2009

The ventral lateral geniculate nucleus (vLGN) has been implicated in numerous functions including circadian rhythms, brightness discrimination, pupillary light reflex, and other visuomotor functions. The contribution of inhibitory mechanisms in the regulation of vLGN neuron excitability remains unexplored. We examined the actions of metabotropic glutamate receptor (mGluR) activation on the intrinsic excitability and inhibitory synaptic transmission in different lamina of vLGN. Activation of mGluRs exerts distinct pre- and postsynaptic actions in vLGN neurons. In the lateral magnocellular subdivision of vLGN (vLGNl), the general mGluR agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (ACPD) enhanced the frequency of GABAA receptor-mediated spontaneous inhibitory postsynaptic currents (sIPSC) that persisted in the presence of sodium channel blocker tetrodotoxin (TTX) in a subpopulation of neurons (TTX insensitive). This increase is attributed to the increased output of dendritic GABA release from vLGN interneurons. In contrast, in the medial subdivision of vLGN (vLGNm), the mGluR agonist-mediated increase in sIPSC frequency was completely blocked by TTX. The selective Group I mGluR agonist ( RS)-3,5-dihydroxyphenylglycine (DHPG) increased sIPSC frequency, whereas the selective Group II mGluR agonist (2 R, 4 R)-4-aminopyrrolidine-2,4-dicarboxylate (APDC) significantly decreased sIPSC frequency in vLGNl neurons. Optic tract stimulation also produced an mGluR-dependent increase in sIPSC frequency in vLGNl neurons. In contrast, we were unable to synaptically evoke alterations in sIPSC activity in vLGNm neurons. In addition to these presynaptic actions, DHPG depolarized both vLGNl and vLGNm neurons. In vLGN interneurons, mGluR activation produced opposing actions: APDC hyperpolarized the membrane potential, whereas DHPG produced a membrane depolarization. The present findings demonstrate diverse actions of mGluRs on vLGN neurons localized within different vLGN lamina. Considering these different lamina are coupled with distinct functional roles, thus these diverse actions may be involved in distinctive forms of visual and visuomotor information processing.
Autophagy in Ischemic Heart Disease
Authors: Gustafsson Åsa B. , Gottlieb Roberta A.
Published: January 2009

Autophagy is a major catabolic pathway by which mammalian cells degrade and recycle macromolecules and organelles. It plays a critical role in removing protein aggregates, as well as damaged or excess organelles, to maintain intracellular homeostasis and to keep the cell healthy. In the heart, autophagy occurs at low levels under normal conditions, and defects in this process cause cardiac dysfunction and heart failure. However, this pathway is rapidly upregulated under environmental stress conditions, including ATP depletion, reactive oxygen species, and mitochondrial permeability transition pore opening. Although autophagy is enhanced in various pathophysiological conditions, such as during ischemia and reperfusion, the functional role of increased autophagy is not clear and is currently under intense investigation. In this review, we discuss the evidence for autophagy in the heart in response to ischemia and reperfusion, identify factors that regulate autophagy, and analyze the potential roles autophagy might play in cardiac cells.
WTO Accessions: The Story So Far
Authors: Milthorp Peter
Published: January 2009

Drawing on his thirteen years of experience as a Counsellor in the Accessions Division of the WTO Secretariat, Peter Milthorp describes accession as consisting of 'government-to-government negotiation, conducted at two mutually interactive levels'. The multilateral negotiations among the acceding country and the collective WTO membership correspond to Putnam's Level I; while the bilateral negotiations between the acceding country and individual members to agree on market access commitments require domestic bargaining and coalition building, and provide evidence of Putnam's Level II schema. Milthorp argues that the most arduous negotiations fall upon the government of the acceding country (that is, Level II), as it must develop a focused yet flexible negotiating mandate, implement economic reforms that may cause short-term hardship to some previously protected sectors, and ensure that negotiations progress steadily — all in order to retain political support for ratification. For accession negotiations to reach the end-game, negotiators must thus engage in both international and domestic diplomacy to create a balanced package that is acceptable to both WTO members as well as domestic stakeholders.
Non-Market Economies' Accessions to the WTO: Evolution of the Approach and Implications for the Organization
Authors: Huang Chieh
Published: January 2009

The General Agreement on Tariffs and Trade (GATT) and its successor, the Word Trade Organization (WTO), have been the main forum of international trade since the end of the Second World War. The regime is unquestionably based on free-market rules and principles. Yet in the last two decades, formerly planned economies — including Eastern European countries, former Soviet countries and China — have attempted to join the GATT/WTO. To encourage their transition under the influence of free-market principles, and to be a truly global trade organization, the GATT/WTO has accepted applicants with a reforming planned economy. This article studies the evolution of the GATT/WTO's approaches to integrate non-market economies and shows that the approach to integrate non-market economies during the WTO era is significantly different than during the GATT. While special mechanisms were provided in GATT accession protocols to bridge different market structures, WTO accessions require non-market economies to convert their own market structures. This article holds that this intolerance of different market structures in the WTO reflects the collapse of embedded liberalism and the rise of coercive trade diplomacy. Multilateral trade diplomacy has therefore become a means of imposing a domestic restructuring of economic structures rather than providing a negotiation forum for trade liberalization.
Will Russia Ever Join the WTO?
Authors: Dyker David
Published: January 2009

Why would Russia, a major power, be thwarted for fourteen years in its attempt to join the World Trade Organization (WTO)? Through a detailed examination of Russia's WTO accession negotiations, the diplomatic processes of the WTO's accession procedures are uncovered, showing that this diplomacy is best understood as a complex process where state-level factors and international regime-level factors, such as the rules and conditions of accession, interact. In the Russian case, the dialogue's length partly reflects technical difficulties in specific elements of the negotiations and partly a degree of ambivalence in the Russian government's attitudes towards accession. The Russian economy's high degree of dependence on oil and gas exports has taken the short-run urgency out of the negotiations from the Russian point of view, while reinforcing the medium-term case for accession within the context of a diversification policy. Russia's new President Dmitry Medvedev and new Minister for the Economy Elvira Nabiullina are strongly committed to WTO accession as a basis for developing the Russian economy as an innovation-based economy. Meanwhile, Russia's former President and current Prime Minister Vladimir Putin is sympathetic to that idea, but is inconsistent in his pronouncements. At the regime level, the key obstacles to accession in the past have been Russia's insistence on the freedom to maintain government agricultural subsidies and the reluctance of other WTO members to compromise on this issue. Since the Georgian crisis of August 2008, the United States has tended increasingly to use WTO accession as an instrument of political leverage vis-à-vis Russia. It must be assumed that Georgia will veto any Russian application for membership unless a satisfactory solution to the Abkhazia/South Ossetia issue can be found.
The Value of ENSO Forecast Information to Dual-Purpose Winter Wheat Production in the U.S. Southern High Plains
Authors: Mauget Steve , Zhang John , Ko Jonghan
Published: January 2009

The value of El Niño–Southern Oscillation (ENSO) forecast information to southern high plains winter wheat and cattle-grazing production systems was estimated here by simulation. Although previous work has calculated average forecast value, the approach here was to estimate probabilities of the value of single forecasts from value distributions associated with categorical ENSO forecast conditions. A simple ENSO-phase forecast system’s value was compared with that of an ideal forecast method that exactly predicted the tercile category of regional November–March precipitation. Simulations were conducted for four price scenarios with wheat prices that randomly varied about a historical ($3.22 per bushel) and elevated ($7.00 per bushel) mean and with returns on live weight gain that are consistent with the grain producer leasing pasturage or owning cattle. In the simulations at $3.22 per bushel, the best practices for specific forecast conditions varied with cattle-ownership conditions. However, the ENSO-phase system’s value distributions were comparable to that of the perfect forecast system; thus more-accurate regional precipitation forecasts may not lead to more forecast value at the farm level. In the simulations at $7.00 per bushel, even perfect categorical forecasts produced only minor profit effects, a result that is attributed here to an increased profit margin rather than to increased wheat value. Under both wheat-price conditions, however, the best no-forecast baseline practices are also shown to have value relative to an arbitrarily chosen management practice. Thus, following practices optimized to climatic conditions and current price and cost conditions might increase profits when no forecast information is available.
The Path Density of Interhemispheric Surface-to-Surface Transport. Part I: Development of the Diagnostic and Illustration with an Analytic Model
Authors: Holzer Mark
Published: January 2009

A new path-density diagnostic for atmospheric surface-to-surface transport is formulated. The path density η gives the joint probability that air whose last surface contact occurred on patch Ωi at time ti will make its next surface contact with patch Ωf after a residence time τ ∈ (τ, τ + dτ) and that it can be found in d3r during its surface-to-surface journey. The dependence on τ allows the average surface-to-surface flow rate carried by the paths to be computed. A simple algorithm for using passive tracers to determine η is developed. A key advantage of the diagnostic is that it can be computed efficiently without an adjoint model and using only a moderately large number of tracers. The nature of the path density is illustrated with a one-dimensional advection–diffusion model. In Part II of this study, the path density diagnostic is applied to quantify interhemispheric transport through the troposphere and stratosphere.
On the relationship between morphological and phonological awareness: Effects of training in kindergarten and in first-grade reading
Authors: Casalis Séverine , Colé Pascale
Published: January 2009

This study examined the relationship between phonological and morphological awareness in kindergarten, and their respective influence on learning to read in first grade, through an experimental training design with three groups of children. One experimental group received phonological awareness training while the other received morphological awareness training. The control group did not receive any training. Both training sessions were efficient since the largest pre- and post-test improvements were observed in the trained domains. Reciprocal influence analysis indicated that morphological awareness improved phonological sensitivity, but not the explicit manipulation of phonemes. In addition, phonological awareness training helped children to segment morphemes, but not to derive complex words. Thus, while some processes are shared by both metalinguistic domains, each domain appears to have its own specificity and may develop independently, at least partly. Even though morphological awareness training was found to be efficient at the kindergarten level, no clear impact on reading was found at the first-grade level, while phonological training displayed a clear positive effect on reading.
Mapping Excellence in National Research Systems
Authors: Abramo Giovanni , Andrea D'Angelo Ciriaco , Di Costa Flavia
Published: January 2009

The study of “scientific excellence” is taking on increasing importance in the development of research policies in many nations. However, scientific excellence is difficult to define because of its multidimensional and highly complex character. This work contributes to the state of the art by exploring an effective, simple, and inexpensive bibliometric methodology that further identifies “excellent” centers of research by beginning with the individual researchers affiliated with such centers. The study concentrates on public research organizations in Italy, analyzing 109 scientific categories of research in the “hard” sciences and 157 centers of excellence operating in 60 of these categories. Findings from this first application of the methodology should be considered exploratory and indicative. With a longer period of observation and the addition of further measurements, this methodology could be extended and adapted to a variety of national and supranational contexts, aiding policy decisions at various levels.
The Evolution of the National Early Childhood Technical Assistance Center
Authors: Gallagher James J. , Danaher Joan C. , Clifford Richard M.
Published: January 2009

This review traces the evolution from 1971 to the present of a national technical assistance (TA) program to support the creation, expansion, and improvement of services for infants, toddlers, and preschoolers with special needs. From its beginning as a TA resource for demonstration projects, to linking outreach projects' expertise with state efforts to expand services, to supporting national constituencies across the research, development, and policy communities, to promoting program improvement and accountability for results, the OSEP-funded national early childhood TA center has been an important piece of a comprehensive infrastructure for early childhood special education. Through its collaboration with other agencies' early childhood TA programs, the National Early Childhood Technical Assistance Center is committed to influencing the development of an infrastructure for early childhood to better serve all of our children.
Development and Evaluation of the Social-Emotional Learning Scale
Authors: Coryn Chris L. S. , Spybrook Jessaca K. , Evergreen Stephanie D. H. , Blinkiewicz Meg
Published: January 2009

This article presents the development and evaluation of a measurement device designed to assess elementary-aged students' social-emotional learning needs. A sample of 633 fourth-, fifth-, and sixth-grade elementary students from 11 public schools in a midsized Midwestern U.S. city was used to evaluate the reliability and validity of the 20-item Social-Emotional Learning Scale (SELS) for the sample. A correlated three-factor model consisting of the factors Task Articulation, Peer Relationships, and Self-Regulation was fit using maximum likelihood estimation and found to be adequate. For the sample, the SELS demonstrated evidence of both precision and accuracy, including internal consistency as well as convergent and discriminant validity. Potential applications for the SELS and further research are discussed.
Chronic Hepatitis B Infection: Principles of Therapy
Authors: Scarsi Kimberly K. , Darin Kristin M.
Published: January 2009

Chronic hepatitis B is a global health concern in many resource-limited settings due to perinatal or pediatric hepatitis B virus transmission. In the United States, pediatric infection has been virtually eliminated due to maternal screening during pregnancy and the availability of an effective vaccine. However, young adults remain an at-risk group for hepatitis B virus infection due to sexual transmission and injection drug use. The frequency of progression from acute hepatitis B virus infection to chronic hepatitis B infection depends on multiple factors, including host immune function and age at time of hepatitis B virus infection. Fortunately, there are 7 currently approved therapies for chronic hepatitis B infection, and several emerging therapies that show promise. Despite the availability of these agents, many clinical questions still surround chronic hepatitis B therapy including when to start therapy, which agent is ideal for first and second line therapy, the appropriate duration of therapy, and the role of combination antiviral therapy. This review focuses on agents available for chronic hepatitis B management, including pharmacology, safety and efficacy data, monitoring parameters, and the role for each in chronic hepatitis B therapy in adult patients.