bluuebunny/crossref_metadata_2025 huggingface dataset:
Age Accounts for Racial Differences in Ischemic Stroke Volume in a Population-Based Study
Authors: Zakaria Tarek , Lindsell Christopher J. , Kleindorfer Dawn , Alwell Kathleen , Moomaw Charles J. , Woo Daniel , Szaflarski Jerzy P. , Khoury Jane , Miller Rosie , Broderick Joseph P. , Kissela Brett
Published: August 2008

Background: The stroke volume among black ischemic stroke patients in phase I of the population-based Greater Cincinnati/Northern Kentucky Stroke Study (GCNKSS) was smaller than reported among acute stroke studies, with a median stroke volume of 2.5 cm. However, it is not known if stroke volume was similar between black and white patients within the same study population. Methods: Phase II of the GCNKSS identified all ischemic strokes between July 1993 and June 1994. The stroke volume was estimated by study physicians using the modified ellipsoid method. Analysis of stroke volume by race, sex and age was performed for strokes with a measurable lesion of ≧0.5 cm3. Results: Among verified cases of ischemic stroke, 334 patients were eligible for this analysis. There were 191 whites (57%) and 143 blacks (43%). The mean age was 69.4 years. The median stroke volume for all patients was 8.8 cm3 (range 0.5–540), with a mean of 36.4 cm3. Stroke volume was not different between men and women, and it tended to increase with age. Although stroke volume was significantly higher among whites, age was a confounding factor. Subsequent analysis of stroke volume stratified by age showed no difference between blacks and whites in any age group. Conclusions: Our data show that most ischemic stroke lesions, regardless of the race, are of small size, and this may be an important reason for the low percentageof strokes treated currently with tissue-type plasminogen activator. The association of age with stroke volume requires further study.
Treatment Mapping – A Systematic Methodology to Assess Quality, Efficiency and Variability in the Hemodialysis Delivery Process
Authors: Alquist Maria , Bosch Juan P.
Published: August 2008

Background/Aims: Radical thinking about the design of industrial processes has greatly improved the quality and efficiency of manufacturing and services. Applying similar methods in healthcare to deliver quality care at lower costs would be valuable. Methods: We have developed and validated a methodology – Treatment Mapping – to analyze the hemodialysis (HD) delivery as an operational process. Results: The methodology was well applicable in the 26 Gambro Healthcare clinics studied (Europe, Taiwan, USA). Monitor process, patient process and dialysis treatment times (mean ± SD) were 324.4 ± 46.0, 272.2 ± 34.5 and 221.6 ± 28.8 min, respectively. In general, significant variability in process cycle times was found in the clinics studied. Conclusion: HD delivery is a complex process influenced by patient characteristics, monitor/disposables design, staff skills and clinic practices and physical layout. The Treatment Mapping methodology is a useful tool to analyze the HD delivery from a process quality and process operational perspective.
Potential Role of Proprotein Convertase SKI-1 in the Mineralization of Primary Bone
Authors: Gorski Jeff P. , Huffman Nichole T. , Cui Chaoying , Henderson Ellen P. , Midura Ronald J. , Seidah Nabil G.
Published: August 2008

The biochemical mechanism controlling nucleation of mineral crystals in developing bone, along with the growth and propagation of these crystals once formed, remains poorly understood. To define the nucleation mechanism, a proteomics analysis was begun on isolated biomineralization foci (BMF), sites of initial crystal nucleation in osteoblastic cell cultures and in primary bone. Comparative analyses of the protein profile for mineralized BMF with that for total osteoblast cultures revealed the latter were enriched in several proteins including BAG-75 and BSP, as well as fragments of each. When 12 protease inhibitors were added separately to UMR 106-01 osteoblastic cultures, only the serine protease inhibitor 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride (AEBSF) blocked cleavage of BAG-75 and BSP, and prevented mineral crystal nucleation within BMF. Consideration of the specificities of the inhibitors tested and the fact that AEBSF inhibition was not dependent upon inclusion of FBS in the culture media indicated that mineral nucleation does not require serine protease plasmin, thrombin, kallikrein, urokinase, C1s or furin. In contrast, SKI-1 (S1P or site-1) is a membrane-bound serine protease inhibitable by AEBSF. We show here for the first time that mineralizing UMR 106 cells express a 98-kDa active, soluble form of SKI-1 within BMF. In contrast, nonmineralizing UMR cells appear to differentially process SKI-1 into smaller immunoreactive fragments (<35 kDa). These findings suggest that SKI-1 plays a direct or indirect role in assembly of functional nucleation complexes containing BAG-75 and BSP and their fragments, thus facilitating initial mineral nucleation within these biomineralization foci.
Phosphorylation of Osteopontin Peptides Mediates Adsorption to and Incorporation into Calcium Oxalate Crystals
Authors: O’Young Jason , Chirico Sara , Al Tarhuni Nehal , Grohe Bernd , Karttunen Mikko , Goldberg Harvey A. , Hunter Graeme K.
Published: August 2008

Phosphorylated peptides of osteopontin (OPN) have been shown to inhibit the growth of the {100} face of calcium oxalate monohydrate (COM). The inhibitory potency has been shown to be dependent on the phosphate content of the peptide. The purpose of this study is to better understand the means by which phosphate groups promote crystal growth inhibition by OPN peptides. Peptides of rat bone OPN 220–235 peptides have been synthesized with zero (P0), 1 (P1) or 3 (P3) phosphate modifications. COM crystals were grown in the presence of 0.1–10 μg of P0, P1 or P3. P0 incorporation into COM crystals was evident at 10 μg/ml of peptide, whereas the phosphorylated peptides P1 and P3 were incorporated at all tested concentrations. At 5 μg/ml of P3, COM crystals exhibited a ‘dumbbell’ morphology. To study the peptide-mineral interaction, surface frequency plots were constructed from molecular dynamics simulations of OPN peptide adsorption. Carboxylate and phosphate groups were found to adsorb in specific orientations to the COM {100} surface. In conclusion, it appears that the phosphate groups on OPN peptides are capable of interacting with the COM {100} surface. This interaction appears to increase the adsorption energy of the peptide to the surface, thus enhancing its inhibitory potency.
Studies of the DMP1 57-kDa Functional Domain both in vivo and in vitro
Authors: Lu Yongbo , Qin Chunlin , Xie Yixia , Bonewald Lynda F. , Feng Jian Q.
Published: August 2008

Dmp1-null mice and patients with mutations in dentin matrix protein 1 (DMP1) resulting in autosomal recessive hypophosphatemic rickets display similar skeletal defects. As mutations were observed in the last 18 amino acids of DMP1 in 1 subset of patients and as fragments of intact DMP1, a 37-kDa N-terminal and a 57-kDa C-terminal fragment, have been purified from bone and dentin, we hypothesized that the cleaved 57-kDa C-terminal fragment is the essential functional domain of DMP1. To test this hypothesis, different forms of recombinant DMP1 were expressed in 293EBNA, CHO and 2T3 cells. The results showed that DMP1 was processed into a 37-kDa N-terminal and a 57-kDa C-terminal fragment in vitro in all cell lines examined. DMP1 processing in CHO cells was blocked by a furin protease inhibitor, decanoyl-Arg-Val-Lys-Arg-chloromethyl ketone, in a dose-dependent manner. Coexpression of PHEX, a potential upstream protease, had no apparent effect on DMP1 cleavage in 293EBNA cells, suggesting that PHEX may not be required for DMP1 processing. To test the in vivo role of the C-terminal fragment, transgenic mice overexpressing full-length DMP1 or the 57-kDa fragment controlled by the 3.6-kb Col1 promoter were generated. Overexpression of these transgenes had no effect on the wild-type skeleton, but on the Dmp1-null background showed expression in the osteoblast layer and throughout the bone matrix leading to the rescue of the null bone phenotype. This suggests that the 57-kDa C-terminal fragment may be able to recapitulate the function of intact DMP1 in vivo.
Transcriptional Regulation of Osteoblasts
Authors: Franceschi Renny T. , Ge Chunxi , Xiao Guozhi , Roca Hernan , Jiang Di
Published: August 2008

The differentiation of osteoblasts from mesenchymal precursors requires a series of cell fate decisions controlled by a hierarchy of transcription factors. These include RUNX2, Osterix (OSX), ATF4 and a large number of nuclear coregulators. During bone development, initial RUNX2 expression coincides with the formation of mesenchymal condensations and precedes the branching of chondrogenic and osteogenic lineages. Given its central role in bone development, it is not surprising that RUNX2 is subject to a variety of controls. These include posttranslational modification, especially phosphorylation, and interactions with accessory nuclear factors. Specific examples of RUNX2 regulation to be reviewed include phosphorylation by the ERK/MAP kinase pathway and interactions with DLX5. RUNX2 is regulated via phosphorylation of critical serine residues in the proline/serine/threonine domain. In vivo, the transgenic expression of constitutively active MAP kinase in osteoblasts accelerated skeletal development, while a dominant-negative MAPK retarded development in a RUNX2-dependent manner. DLX5-RUNX2 complexes can be detected in osteoblasts and this interaction plays a critical role in maintaining osteoblast-specific expression of the bone sialoprotein gene. These studies allow us to begin understanding the complex mechanisms necessary to fine-tune bone formation as mesenchymal progenitors progress down the osteoblast lineage.
Cognitive and Emotional Modulation of Brain Default Operation
Authors: Pallesen Karen Johanne , Brattico Elvira , Bailey Christopher J. , Korvenoja Antti , Gjedde Albert
Published: August 2008

Goal-directed behavior lowers activity in brain areas that include the medial frontal cortex, the medial and lateral parietal cortex, and limbic and paralimbic brain regions, commonly referred to as the “default network.” These activity decreases are believed to reflect the interruption of processes that are ongoing when the mind is in a restful state. Previously, the nature of these processes was probed by varying cognitive task parameters, but the presence of emotional processes, while often assumed, was little investigated. With fMRI, we studied the effect of systematic variations of both cognitive load and emotional stimulus connotation on task-related decreases in the default network by employing an auditory working memory (WM) task with musical sounds. The performance of the WM task, compared to passive listening, lowered the activity in medial and lateral, prefrontal, parietal, temporal, and limbic regions. In a subset of these regions, the magnitude of decrease depended on the memory load; the greater the cognitive load, the larger the magnitude of the observed decrease. Furthermore, in the right amygdala and the left precuneus, areas previously associated with processing of unpleasant dissonant musical sounds, there was an interaction between the experimental condition and the stimulus type. The current results are consistent with the previously reported effect of task difficulty on task-related brain activation decreases. The results also indicate that task-related decreases may be further modulated by the emotional stimulus connotation.
Exploring the Neural Correlates of Social Stereotyping
Authors: Quadflieg Susanne , Turk David J. , Waiter Gordon D. , Mitchell Jason P. , Jenkins Adrianna C. , Macrae C. Neil
Published: August 2008

Judging people on the basis of cultural stereotypes is a ubiquitous facet of daily life, yet little is known about how this fundamental inferential strategy is implemented in the brain. Using fMRI, we measured neural activity while participants made judgments about the likely actor (i.e., person-focus) and location (i.e., place-focus) of a series of activities, some of which were associated with prevailing gender stereotypes. Results revealed that stereotyping was underpinned by activity in areas associated with evaluative processing (e.g., ventral medial prefrontal cortex, amygdala) and the representation of action knowledge (e.g., supramarginal gyrus, middle temporal gyrus). In addition, activity accompanying stereotypic judgments was correlated with the strength of participants' explicit and implicit gender stereotypes. These findings elucidate how stereotyping fits within the neuroscience of person understanding.
Impaired List Learning Is Not a General Property of Frontal Lesions
Authors: Alexander Michael P. , Stuss Donald , Gillingham Susan
Published: August 2008

Background: List-learning tasks are frequently used to provide measures of “executive functions” that are believed necessary for successful memory performance. Small sample sizes, confounding anomia, and incomplete representation of all frontal regions have prevented consistent demonstration of distinct regional frontal effects on this task. Objective: To confirm specific effects of lesions in different frontal regions. Subjects: Forty-one patients with chronic focal frontal lesions and 38 control subjects. There were no group differences in naming scores. Methods: Two word lists were presented, one with unblocked words from related categories and one in a preblocked format. Standard measures of learning, recall, recognition, and strategies were obtained, first for the frontal group as a whole and then for large but defined frontal regions. For all measures with significant group differences, a lesion “hotspotting” method identified possible specific regional injury effects. Results: The frontal group was impaired on almost all measures, but impairments on most measures were particularly identified with lesions in the left superior frontal lobe (approximately area 9s) and some deficits in learning processes were surprisingly more prominent on the blocked list. Conclusion: Difficulty with list learning is not a general property of all frontal lesions. Lesions in different frontal regions impair list learning through specific mechanisms, and these effects may be modified by manipulations of the task structure.
Dissociation of Frontal and Medial Temporal Lobe Activity in Maintenance and Binding of Sequentially Presented Paired Associates
Authors: Hales Jena B. , Israel Sarah L. , Swann Nicole C. , Brewer James B.
Published: August 2008

Substructures of the prefrontal cortex (PFC) and the medial-temporal lobe are critical for associating objects presented over time. Previous studies showing frontal and medial-temporal involvement in associative encoding have not addressed the response specificity of these regions to different aspects of the task, which include instructions to associate and binding of stimuli. This study used a novel paradigm to temporally separate these two components of the task by sequential presentation of individual images with or without associative instruction; fMRI was used to investigate the temporal involvement of the PFC and the parahippocampal cortex in encoding each component. Although both regions showed an enhanced response to the second stimulus of a pair, only the PFC had increased activation during the delay preceding a stimulus when associative instruction was given. These findings present new evidence that prefrontal and medial-temporal regions provide distinct temporal contributions during associative memory formation.
When Time Shapes Behavior: fMRI Evidence of Brain Correlates of Temporal Monitoring
Authors: Vallesi Antonino , McIntosh Anthony R. , Shallice Tim , Stuss Donald T.
Published: August 2008

Time processing may shape behavior in several ways, although the underlying neural correlates are still poorly understood. When preparatory intervals between stimuli vary randomly in a block, for instance, responses are faster as the interval gets longer. This effect, known as variable foreperiod (FP) effect, has been attributed to a process monitoring the conditional probability of stimulus occurrence as the interval increases. Previous evidence points to the right dorsolateral prefrontal cortex (DLPFC) as a possible node for this time-monitoring process. The present study addresses this hypothesis with functional magnetic resonance imaging (fMRI). Block-design fMRI was used on 14 young participants while they performed a visual discrimination task with fixed and variable preparatory intervals (FPs) of 1 and 3 sec. In the variable versus fixed FP contrast, the right DLPFC and a visual area were more activated in the subgroup of participants who showed a reliable variable FP effect than in another subgroup who did not show that effect. Only the activation in the right DLPFC was supported by a significant interaction between FP condition (variable vs. fixed) and group. This finding may reflect possible differences in the strategy adopted by the two subgroups of participants while performing the task. Although results suggest that many brain areas may be involved in preparation over time, the role of the right DLPFC is critical to observe the strategically mediated behavioral effects in the variable FP paradigm.
Neurons in the Frontal Lobe Encode the Value of Multiple Decision Variables
Authors: Kennerley Steven W. , Dahmubed Aspandiar F. , Lara Antonio H. , Wallis Jonathan D.
Published: August 2008

A central question in behavioral science is how we select among choice alternatives to obtain consistently the most beneficial outcomes. Three variables are particularly important when making a decision: the potential payoff, the probability of success, and the cost in terms of time and effort. A key brain region in decision making is the frontal cortex as damage here impairs the ability to make optimal choices across a range of decision types. We simultaneously recorded the activity of multiple single neurons in the frontal cortex while subjects made choices involving the three aforementioned decision variables. This enabled us to contrast the relative contribution of the anterior cingulate cortex (ACC), the orbito-frontal cortex, and the lateral prefrontal cortex to the decision-making process. Neurons in all three areas encoded value relating to choices involving probability, payoff, or cost manipulations. However, the most significant signals were in the ACC, where neurons encoded multiplexed representations of the three different decision variables. This supports the notion that the ACC is an important component of the neural circuitry underlying optimal decision making.
Anterior Intraparietal Sulcus is Sensitive to Bottom–Up Attention Driven by Stimulus Salience
Authors: Geng Joy J. , Mangun George R.
Published: August 2008

Frontal eye fields (FEF) and anterior intraparietal sulcus (aIPS) are involved in the control of voluntary attention in humans, but their functional differences remain poorly understood. We examined the activity in these brain regions as a function of task-irrelevant changes in target and nontarget perceptual salience during a sustained spatial attention task. Both aIPS and FEF were engaged during selective attention. FEF, but not aIPS, was sensitive to the direction of spatial attention. Conversely, aIPS, but not FEF, was modulated by the relative perceptual salience of the target and nontarget stimuli. These results demonstrate separable roles for FEF and aIPS in attentional control with FEF more involved in goal-directed spatial attention and aIPS relatively more sensitive to bottom–up attentional influences driven by stimulus salience.
Negotiating with Terrorists: A Discrete Form of Diplomacy
Authors: Olivier Faure Guy
Published: August 2008

Crisis negotiation has been burdened with an additional and most problematic task, that of dealing with terrorist issues. Negotiators must engage in a very peculiar type of diplomacy because, officially, states do not negotiate with terrorists. This track-II diplomacy involves an asymmetrical relationship between a state and an often nebulous and evasive group. Its management is most paradoxical, for the negotiation is a non-negotiation and the counterparts are the most unlikely of negotiators. This article analyses the very specific elements of such negotiation, in which the actors no longer play classical diplomatic roles but instead fulfil a much less urbane function that is embedded in the register of terror, even murder. It examines methods that are fundamentally alien to classical diplomacy because of the nature of the counterpart (who is not perceived as legitimate/equal), the issues at stake, the context, and the paradigms governing negotiating with terrorists, where psychological asymmetry and poor communication are basic attributes. Specific processes such as demonization and media management, as well as negotiation-effectiveness evaluation methods, are also studied. Two types of situations are finally investigated, those where discussions can take place immediately, such as hostage-taking via kidnapping or barricade hostage-taking, and those where the potential for negotiation must be created because the terrorists make no demands and consider their actions as strictly punitive.
The Politics of the State Visit
Authors: Goldstein Erik
Published: August 2008

State visits are one of the oldest forms of diplomatic contact between the leaders of states. Redolent of the pomp of previous ages, the modern era has seen a vertical rise in the frequency of state visits. This article examines the mechanics of the state visit and considers their purpose in contemporary diplomacy, as well as some of their unintended consequences.
Reflections on Public Diplomacy after the Danish Cartoon Crises: From Crisis Management to Normal Public Diplomacy Work
Authors: Andreasen Uffe
Published: August 2008

The Danish cartoon crisis was resurrected in Spring 2008 when the Mohammed cartoons were reprinted as an expression of solidarity following the revelation that definite death threats had been made to one of the cartoonists. During both crises the Danish government stuck to the principle of transparency and stood its ground, almost to excess, or so some thought. But the government's stance has possibly paid off, at least in the long run. A crisis situation is an inappropriate moment for a country to start a polemical discussion with its 'opposite number'. But as soon as things have quietened down, reconstruction work must take place. To stick one's head in the sand during this second phase is dangerous for a country's reputation. This article argues that the answer to this dilemma is to concentrate your counter-attack on the 'disputable area'. And the best method is to invite a meaningful dialogue.
Identifying the Uncertainty in Determining Satellite-Derived Atmospheric Motion Vector Height Attribution
Authors: Velden Christopher S. , Bedka Kristopher M.
Published: August 2008

This study investigates the assignment of pressure heights to satellite-derived atmospheric motion vectors (AMVs), commonly known as cloud-drift and water vapor–motion winds. Large volumes of multispectral AMV datasets are compared with collocated rawinsonde wind profiles collected by the U.S. Department of Energy Atmospheric Radiation Measurement Program at three geographically disparate sites: the southern Great Plains, the North Slope of Alaska, and the tropical western Pacific Ocean. From a careful analysis of these comparisons, the authors estimate that mean AMV observation errors are ∼5–5.5 m s−1 and that vector height assignment is the dominant factor in AMV uncertainty, contributing up to 70% of the error. These comparisons also reveal that in most cases the RMS differences between matched AMVs and rawinsonde wind values are minimized if the rawinsonde values are averaged over specified layers. In other words, on average, the AMV values better correlate to a motion over a mean tropospheric layer rather than to a traditionally assigned discrete level. The height assignment behavioral characteristics are specifically identified according to AMV height (high cloud vs low cloud), type (spectral bands; clear vs cloudy), geolocation, height assignment method, and amount of environmental vertical wind shear present. The findings have potentially important implications for data assimilation of AMVs, and these are discussed.
The CM-SAF and FUB Cloud Detection Schemes for SEVIRI: Validation with Synoptic Data and Initial Comparison with MODIS and CALIPSO
Authors: Reuter M. , Thomas W. , Albert P. , Lockhoff M. , Weber R. , Karlsson K-G. , Fischer J.
Published: August 2008

The Satellite Application Facility on Climate Monitoring (CM-SAF) is aiming to retrieve satellite-derived geophysical parameters suitable for climate monitoring. CM-SAF started routine operations in early 2007 and provides a climatology of parameters describing the global energy and water cycle on a regional scale and partially on a global scale. Here, the authors focus on the performance of cloud detection methods applied to measurements of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on the first Meteosat Second Generation geostationary spacecraft. The retrieved cloud mask is the basis for calculating the cloud fractional coverage (CFC) but is also mandatory for retrieving other geophysical parameters. Therefore, the quality of the cloud detection directly influences climate monitoring of many other parameters derived from spaceborne sensors. CM-SAF products and results of an alternative cloud coverage retrieval provided by the Institut für Weltraumwissenschaften of the Freie Universität in Berlin, Germany (FUB), were validated against synoptic measurements. Furthermore, and on the basis of case studies, an initial comparison was performed of CM-SAF results with results derived from the Moderate Resolution Imaging Spectrometer (MODIS) and from the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP). Results show that the CFC from CM-SAF and FUB agrees well with synoptic data and MODIS data over midlatitudes but is underestimated over the tropics and overestimated toward the edges of the visible Earth disk.
Errors in Estimating Raindrop Size Distribution Parameters Employing Disdrometer and Simulated Raindrop Spectra
Authors: Cao Qing , Zhang Guifu
Published: August 2008

There have been debates and differences of opinion over the validity of using drop size distribution (DSD) models to characterize precipitation microphysics and to retrieve DSD parameters from multiparameter radar measurements. In this paper, simulated and observed rain DSDs are used to evaluate moment estimators. Seven estimators for gamma DSD parameters are evaluated in terms of the biases and fractional errors of five integral parameters: radar reflectivity (ZH), differential reflectivity (ZDR), rainfall rate (R), mean volume diameter (Dm), and total number concentration (NT). It is shown that middle-moment estimators such as M234 (using the second-third-fourth moments) produce smaller errors than lower- and higher-moment estimators if the DSD follows the gamma distribution. However, if there are model errors, the performance of M234 degrades. Even though the DSD parameters can be biased in moment estimators, integral parameters are usually not. Maximum likelihood (ML) and L-moment (LM) estimators perform similarly to low-moment estimators such as M012. They are sensitive to both model error and the measurement errors of the low ends of DSDs. The overall differences among M234, M246, and M346 are not substantial for the five evaluated parameters. This study also shows that the discrepancy between the radar and disdrometer observations cannot be reduced by using these estimators. In addition, the previously found constrained-gamma model is shown not to be exclusively determined by error effects. Rather, it is equivalent to the mean function of normalized DSDs derived through Testud’s approach, and linked to precipitation microphysics.
Blocking in Areas of Complex Topography, and Its Influence on Rainfall Distribution
Authors: Hughes Mimi , Hall Alex , Fovell Robert G.
Published: August 2008

Using a 6-km-resolution regional climate simulation of Southern California, the effect of orographic blocking on the precipitation climatology is examined. To diagnose whether blocking occurs, precipitating hours are categorized by a bulk Froude number. The precipitation distribution becomes much more spatially homogeneous as the Froude number decreases, and an inspection of winds confirms that this results from the increasing prevalence of orographic blocking. Low Froude (Froude approximately less than 1), blocked cases account for a large fraction of climatological precipitation, particularly at the coastline where more than half is attributable to blocked cases. Thus, the climatological precipitation–slope relationship seen in observations and in the simulation is a hybrid of blocked and unblocked cases.

Simulated precipitation distributions are compared to those predicted by a simple linear model that includes only rainfall arising from direct forced topographic ascent. The agreement is nearly perfect for high Froude (Froude substantially larger than 1) cases but degrades dramatically as the index decreases; as blocking becomes more prevalent, the precipitation–slope relationship becomes continuously weaker than that predicted by the linear model. Because of its high fidelity during unblocked cases, it is surmised that blocking effects are the primary limitation preventing the linear model from accurately representing precipitation climatology and that the representation would be significantly improved during low Froude hours by the addition of a term to reduce the effective slope of the topography. These results suggest orographic blocking may substantially affect climatological precipitation distributions in similarly configured coastal areas.
Large Eddy Simulation of the Diurnal Cycle in Southeast Pacific Stratocumulus
Authors: Caldwell Peter , Bretherton Christopher S.
Published: August 2008

This paper describes a series of 6-day large eddy simulations of a deep, sometimes drizzling stratocumulus-topped boundary layer based on forcings from the East Pacific Investigation of Climate (EPIC) 2001 field campaign. The base simulation was found to reproduce the observed mean boundary layer properties quite well. The diurnal cycle of liquid water path was also well captured, although good agreement appears to result partially from compensating errors in the diurnal cycles of cloud base and cloud top due to overentrainment around midday. At all times of the day, entrainment is found to be proportional to the vertically integrated buoyancy flux. Model stratification matches observations well; turbulence profiles suggest that the boundary layer is always at least somewhat decoupled. Model drizzle appears to be too sensitive to liquid water path and subcloud evaporation appears to be too weak. Removing the diurnal cycle of subsidence had little effect on simulated liquid water path. Simulations with changed droplet concentration and drizzle susceptibility showed large liquid water path differences at night, but differences were quite small at midday. Droplet concentration also had a significant impact on entrainment, primarily through droplet sedimentation feedback rather than through drizzle processes.
Are Changes in Global Precipitation Constrained by the Tropospheric Energy Budget?
Authors: Lambert F. Hugo , Allen Myles R.
Published: August 2008

A tropospheric energy budget argument is used to analyze twentieth-century precipitation changes. It is found that global and ocean-mean general circulation model (GCM) precipitation changes can be understood as being due to the competing direct and surface-temperature-dependent effects of external climate forcings. In agreement with previous work, precipitation is found to respond more strongly to anthropogenic and volcanic sulfate aerosol and solar forcing than to greenhouse gas and black carbon aerosol forcing per unit temperature. This is due to the significant direct effects of greenhouse gas and black carbon forcing. Given that the relative importance of different forcings may change in the twenty-first century, the ratio of global precipitation change to global temperature change may be quite different. Differences in GCM twentieth- and twenty-first-century values are tractable via the energy budget framework in some, but not all, models. Changes in land-mean precipitation, on the other hand, cannot be understood at all with the method used here, even if land–ocean heat transfer is considered. In conclusion, the tropospheric energy budget is a useful concept for understanding the precipitation response to different forcings but it does not fully explain precipitation changes even in the global mean.
The Role of Eddies in the Southern Ocean Temperature Response to the Southern Annular Mode
Authors: Screen James A. , Gillett Nathan P. , Stevens David P. , Marshall Gareth J. , Roscoe Howard K.
Published: August 2008

The role of eddies in modulating the Southern Ocean response to the southern annular mode (SAM) is examined, using an ocean model run at multiple resolutions from coarse to eddy resolving. The high-resolution versions of the model show an increase in eddy kinetic energy that peaks 2–3 yr after a positive anomaly in the SAM index. Previous work has shown that the instantaneous temperature response to the SAM is characterized by predominant cooling south of 45°S and warming to the north. At all resolutions the model captures this temperature response. This response is also evident in the coarse-resolution implementation of the model with no eddy mixing parameterization, showing that eddies do not play an important role in the instantaneous response. On the longer time scales, an intensification of the mesoscale eddy field occurs, which causes enhanced poleward heat flux and drives warming south of the oceanic Polar Front. This warming is of greater magnitude and occurs for a longer period than the initial cooling response. The results demonstrate that this warming is surface intensified and strongest in the mixed layer. Non-eddy-resolving models are unable to capture the delayed eddy-driven temperature response to the SAM. The authors therefore question the ability of coarse-resolution models, such as those commonly used in climate simulations, to accurately represent the full impacts of the SAM on the Southern Ocean.
Characterizing and Modeling Temporal and Spatial Trends in Rainfall Extremes
Authors: Aryal Santosh K. , Bates Bryson C. , Campbell Edward P. , Li Yun , Palmer Mark J. , Viney Neil R.
Published: August 2008

A hierarchical spatial model for daily rainfall extremes that characterizes their temporal variation due to interannual climatic forcing as well as their spatial pattern is proposed. The model treats the parameters of at-site probability distributions for rainfall extremes as “data” that are likely to be spatially correlated and driven by atmospheric forcing. The method is applied to daily rainfall extremes for summer and winter half years over the Swan–Avon River basin in Western Australia. Two techniques for the characterization of at-site extremes—peaks-over-threshold (POT) analysis and the generalized extreme value (GEV) distribution—and three climatic drivers—the El Niño–Southern Oscillation as measured by the Southern Oscillation index (SOI), the Southern Hemisphere annular mode as measured by an Antarctic Oscillation index (AOI), and solar irradiance (SI)—were considered. The POT analysis of at-site extremes revealed that at-site thresholds lacked spatial coherence, making it difficult to determine a smooth spatial surface for the threshold parameter. In contrast, the GEV-based analysis indicated smooth spatial patterns in daily rainfall extremes that are consistent with the predominant orientation of storm tracks over the study area and the presence of a coastal escarpment near the western edge of the basin. It also indicated a linkage between temporal trends in daily rainfall extremes and those of the SOI and AOI. By applying the spatial models to winter and summer extreme rainfalls separately, an apparent increasing trend in return levels of summer rainfall to the northwest and decreasing trends in return levels of winter rainfall to the southwest of the region are found.
Can Long Meridional Length Scales Yield Faster Rossby Waves?
Authors: Poulin F. J.
Published: August 2008

There is much interest in better understanding the westward-propagating subinertial signal in the ocean basins because it influences many aspects of the ocean’s circulation. One explanation for the origin of this signal is that it is predominantly composed of Rossby waves. Chelton and Schlax assumed the observations were Rossby waves and compared their phase speeds with those predicted from nondispersive linear quasigeostrophic wave speeds. They concluded that the theory underestimated the observed wave speeds. Recently, in the context of the shallow-water model, Paldor, Rubin, and Mariano found that by including the full meridional variation of the Coriolis parameter, the Rossby waves have faster phase speeds. Here, their analysis is extended to derive a general dispersion relation for stratified Rossby waves that is suitable for both mesoscale and synoptic length scales. Then, realistic profiles of the buoyancy frequency are used to compare the phase speeds from the Ocean Topography Experiment (TOPEX)/Poseidon data with the new theory. It is found that the new theory does not yield any significant increase in Rossby wave speeds.
Spectral Coherence and the Statistical Significance of Turbulent Flux Computations
Authors: Biltoft Christopher A. , Pardyjak Eric R.
Published: August 2008

The squared spectral coherence, a frequency-domain analog of the squared correlation coefficient, identifies the frequencies at which two variables most strongly covary. A simple coherence significance test designed to determine whether coherence peaks exceed critical values expected from chance random number correlations is described. This significance test determines the probability with which coherence peaks are likely to arise out of random turbulence. A statistically significant coherence peak also indicates the likely presence of a significant turbulent flux. The test is illustrated using sonic anemometer–thermometer data acquired in an urban setting and over a salt playa. Successful application of this coherence significance test requires selection of a properly sized data record and a Fourier transform with appropriate windowing. The sampling period should be sufficiently long to span major flux-generating scales of motion up to the cross-spectral gap but not so long that extraneous larger scale motions are included. A record length and transform size that yield equivalent degrees of freedom in the range between 10 and 100 produces the most consistent and reliable significance test results.
Links between Tropical Cyclone Activity and Madden–Julian Oscillation Phase in the North Atlantic and Northeast Pacific Basins
Authors: Barrett Bradford S. , Leslie Lance M.
Published: August 2008

The leading intraseasonal mode of atmospheric and oceanic variability, the Madden–Julian oscillation (MJO), influences tropical and extratropical sea level pressure, temperature, divergent and rotational wind components, moisture, and deep convection. As a 40- to 50-day oscillation, the MJO is also known to influence tropical phenomena, including tropical cyclone (TC) activity in various TC basins. The links between the MJO and multiple measures of TC activity, including genesis, landfall, and an integrative accumulated cyclone energy (ACE) index, were quantified for multiple TC-formation basins across the Western Hemisphere, including the North Atlantic and northeast Pacific Ocean and subbasins, for the period 1978–2006. Using this relatively long (29 yr) TC dataset and employing an upper-tropospheric MJO diagnostic that is physically meaningful over the entire Western Hemisphere, this study extends existing research on the relationships between the MJO and TCs. The NOAA Climate Prediction Center’s operational MJO index, derived from 200-hPa velocity potential data, was divided into three phases. Relative frequencies of the MJO phases were compared with observed levels of TC activity using a binomial distribution hypothesis test. The MJO was found to statistically significantly modulate the frequency of TC genesis, intensification, and landfall in the nine TC basins studied. For example, when an MJO index was large and positive at 120°W, hurricanes and intense hurricanes were 4 times as likely to make landfall in the North Atlantic. This modulation of TC activity, including landfall patterns in the North Atlantic, was physically linked to the upper-atmospheric response to the eastward-propagating MJO and is evident as a dipole of TC activity between Pacific and Atlantic subbasins.
Generalizability Theory Applied to Reading Assessments for Students With Significant Cognitive Disabilities
Authors: Tindal Gerald , Yovanoff Paul , Geller Josh P.
Published: August 2008

Students with significant disabilities must participate in large-scale assessments, often using an alternate assessment judged against alternate achievement standards. The development and administration of this type of assessment must necessarily balance meaningful participation with accurate measurement. In this study, generalizability theory is used to estimate the dependability of reading items and tasks that have been administered using two formats of communication (receptive and expressive). The results reflect a trade-off between meaningful participation and accurate measurement of students with significant cognitive disabilities, particularly when considering the two formats. Significant variance is obtained for persons interacting with tasks, whereas the effect of raters is negligible. Furthermore, these results appear to vary across administrative format.
Testimony from a Popperian Perspective
Authors: Diller Antoni
Published: August 2008

Currently, testimony is studied extensively in Anglo-American philosophy. However, most of this work is done from a justificationist perspective in which philosophers try to justify our reliance on testimony in some way. I agree with Popper that justificationism is radically mistaken. Thus, I construct an account of how we respond to testimony that in no way attempts to justify our reliance on it. This account is not a straightforward exegesis of Popper, as he never tackled testimony systematically. It makes use, however, of several of Popper's key insights and incorporates them into a viable theory of testimony.
Changes in brain orexin levels in a rat model of depression induced by neonatal administration of clomipramine
Authors: Feng P. , Vurbic D. , Wu Z. , Hu Y. , Strohl KP
Published: August 2008

Depression is associated with a deficiency of serotonergic neurons that have been found to suppress orexinergic neurons, which in turn activate these neurons in a feedback loop. This evidence suggests that orexins may be involved in the pathology of depression. Long Evans rats were treated with clomipramine (CLI) and saline (SAL) from postnatal days 8 through 21. One set of rats from both groups was sacrificed at 35 days of age for quantification of orexins in multiple brain regions. At 3—4 months of age a second set of rats was tested for immobility in a forced swim procedure, a common test for depressive signs in rats, and a third set was sacrificed for the quantification of orexins. Compared with the control rats, adult rats with neonatal CLI treatment had (1) increased forced swim immobility and (2) increased orexins A and B in the hypothalamus. However, both orexins A and B levels were decreased in multiple brain regions in the juvenile CLI rats compared with same-age controls. We concluded that although orexin levels were decreased in juvenile CLI rats, adult CLI rats with features of depression had significantly higher levels of hypothalamic orexins compared with adult controls. These results imply that orexins are likely to be involved in the pathological regulation of depression.
Agomelatine, an innovative pharmacological response to unmet needs
Authors: Le Strat Y , Gorwood P
Published: August 2008

Abstract

Most of the available antidepressants, with different pharmacological profiles, such as inhibitors of serotonin reuptake (SSRIs) or norepinephrine reuptake (NRIs) or both (SNRIs), have limitations leading some patients to drop out of treatment. Another direction of research has therefore been undertaken, based initially on the fact that affective disorders are most often characterized by abnormal patterns of circadian rhythms. This consideration has led to the synthesis of agomelatine, a novel antidepressant combining melatonergic MT1 and MT2 agonism and serotonergic 5-HT2C antagonism. The antidepressant effects of agomelatine have been investigated in different animal models, including chronic mild stress, forced swimming, learned helplessness and psychosocial stress. All studies reported an antidepressant-like effect of agomelatine. A resynchronizing activity of agomelatine was seen in animal models for delayed sleep phase syndrome and in several original models of circadian disturbance, such as rodents infected by trypanosome or old hamsters. This activity of agomelatine on circadian rhythms was further confirmed in humans. Furthermore, several randomized, double-blind, placebo-controlled and comparator-controlled studies of agomelatine in the treatment of major depressive disorder indicate that agomelatine is effective and well tolerated.
Arthroscopic Release for Symptomatic Scarring of the Anterior Interval of the Knee
Authors: Steadman J. Richard , Dragoo Jason L. , Hines Sophie L. , Briggs Karen K.
Published: August 2008

Background

Patients with a history of knee trauma or previous surgery may exhibit pain in the infrapatellar region that is refractory to conservative care. This may be due to subtle scarring of the anterior interval.

Hypothesis

Arthroscopic release of a scarred anterior interval will lead to improvement in anterior knee pain.

Study Design

Case series; Level of evidence, 4.

Methods

Twenty-five consecutive patients with isolated scarring of the anterior interval, confirmed with both magnetic resonance imaging (MRI) and arthroscopic examination, were included. All 25 patients had refractory anterior knee pain that was unimproved after a minimum of 6 months of physical therapy and nonsteroidal anti-inflammatory medications and pain during knee extension. All patients had a minimum of 2 previous surgical procedures, and 11 (44%) of the patients had a previous anterior cruciate ligament (ACL) reconstruction. All 25 (100%) patients had an apparent decrease in the cranial excursion of the patella and had a positive Hoffa test result. Fourteen (56%) patients had a preoperative flexion contracture of at least 5°. All patients underwent an isolated arthroscopic anterior interval release.

Results

All patients were evaluated by physical examination and standardized scoring instruments with an average follow-up of 4.0 years (range, 2.0-7.2). Twenty-one patients had full range of motion of the patella in all directions and a negative Hoffa test finding at final follow-up. All 14 (100%) patients with preoperative flexion contractures (>5°) experienced a full return of extension. The average Lysholm score improved from 59 preoperatively to 81 postoperatively ( P < .0001). The average International Knee Documentation Committee (IKDC) score improved from 49 to 70 ( P < .001). There were no complications. Four patients (16%) had failed results and required a second surgical release. Patients with failures had significantly lower preoperative Lysholm scores (score = 40) than those who did not (score = 58) ( P = .022). Three of the failures were workers’ compensation cases.

Conclusion

Scarring of the anterior interval changes the mechanics of the anterior structures of the knee and may lead to refractory anterior knee pain. Arthroscopic anterior interval release successfully provides pain relief in this patient population.