bluuebunny/crossref_metadata_2025 huggingface dataset:
Explicit memory training leads to improved memory for face–name pairs in patients with mild cognitive impairment: Results of a pilot investigation
Authors: HAMPSTEAD BENJAMIN M. , SATHIAN K. , MOORE ANNA BACON , NALISNICK CARRIE , STRINGER ANTHONY Y.
Published: September 2008

Relatively few studies have examined the use of cognitive rehabilitation in patients with mild cognitive impairment (MCI), largely due to the assumption that training will not improve functioning in patients with progressive conditions. Face-name association, an ecologically valid task, is both dependent on the explicit memory system and difficult for MCI patients. During three hour-long sessions, eight patients diagnosed with MCI were trained in the use of explicit memory strategies with 45 face-name pairs. For each pair, they were taught to visually identify a facial feature, link a phonological cue to that feature, and recall the associated name. There was significant improvement in recognition accuracy, along with faster reaction times, for trained face-name pairs. Improved accuracy persisted when tested one month after training. Significant, but less, improvement was also found on untrained stimuli, raising the possibility of generalization of training strategies. Preliminary results suggest strategy-based cognitive rehabilitation may be beneficial in patients with MCI, though these results must be replicated with a control group to rule out practice effects. (JINS, 2008, 14, 883–889.)
Levodopa and executive performance in Parkinson's disease: A randomized study
Authors: PASCUAL-SEDANO BERTA , KULISEVSKY JAIME , BARBANOJ MANEL , GARCÍA-SÁNCHEZ CARMEN , CAMPOLONGO ANTONIA , GIRONELL ALEXANDRE , PAGONABARRAGA JAVIER , GICH IGNASI
Published: September 2008

Parkinson's disease (PD) patients may experience fluctuations in executive performance after oral levodopa (LD). Their relationship with the pharmacokinetic profile of LD and with distinct cognitive processes associated with frontal-basal ganglia circuits is not well understood. In this randomized, double-blind, crossover study we plotted acute cognitive changes in 14 PD patients challenged with faster (immediate-release, IR) versus slower (controlled-release, CR) increases in LD plasma concentrations. We monitored motor status, LD plasma levels, and performance on four tasks of executive function (Wisconsin Card Sorting Test—WCST, Sternberg test, Stroop and Tower of Hanoi), 1 hr before and over +6 hr after IR and CR-LD dose. Analysis of variance demonstrated significant but divergent changes in the Sternberg (6-digit but not 2- and 4-digit) test: improvement after CR-LD and worsening after IR-LD. Marginal improvement (p = .085) was observed with CR-LD in the WCST, while no significant differences were seen for the Stroop or Tower of Hanoi tests. Executive-related performance after LD challenge may differ depending on the LD time-to-peak plasma concentration and specific task demands. A slower rise in LD levels appears to have a more favorable impact on more difficult working memory tests. These results require replication to determine their generalization. (JINS, 2008, 14, 832–841.)
The relationship of neuropsychological functioning to adaptation outcome in adolescents with spina bifida
Authors: HEFFELFINGER AMY K. , KOOP JENNIFER I. , FASTENAU PHILIP S. , BREI TIMOTHY J. , CONANT LISA , KATZENSTEIN JENNIFER , CASHIN SUSAN E. , SAWIN KATHLEEN J.
Published: September 2008

Adolescents with spina bifida (SB) vary in their ability to adapt to the disease, and it is likely that numerous risk and protective factors affect adaptation outcomes. The primary aim was to test neuropsychological impairment, exemplified herein by executive dysfunction, as a risk factor in the Ecological Model of Adaptation for Adolescents with SB. Specific hypotheses were that: (1) executive functioning predicts the adaptation outcome of functional independence in adolescents with SB; (2) executive functioning mediates the impact of neurological severity on functional independence; and (3) family and adolescent protective factors are related to functional independence and moderate the relationship between executive functioning and functional independence. Forty-three adolescents aged 12–21 years completed neuropsychological measures and an interview that assessed risk, adolescent and family protective factors, and functional independence. Age, level of lesion, executive functioning, and the protective factor adolescent activities were significantly correlated with the functional independence outcome. In hierarchical regression analysis, the model accounted for 61% of the variance in functional independence outcomes. Executive functioning mediated the impact of neurological severity on functional independence. (JINS, 2008,14, 793–804.)
Use of MMPI-2 to predict cognitive effort: A hierarchically optimal classification tree analysis
Authors: SMART COLETTE M. , NELSON NATHANIEL W. , SWEET JERRY J. , BRYANT FRED B. , BERRY DAVID T.R. , GRANACHER ROBERT P. , HEILBRONNER ROBERT L.
Published: September 2008

Neuropsychologists routinely rely on response validity measures to evaluate the authenticity of test performances. However, the relationship between cognitive and psychological response validity measures is not clearly understood. It remains to be seen whether psychological test results can predict the outcome of response validity testing in clinical and civil forensic samples. The present analysis applied a unique statistical approach, classification tree methodology (Optimal Data Analysis: ODA), in a sample of 307 individuals who had completed the MMPI-2 and a variety of cognitive effort measures. One hundred ninety-eight participants were evaluated in a secondary gain context, and 109 had no identifiable secondary gain. Through recurrent dichotomous discriminations, ODA provided optimized linear decision trees to classify either sufficient effort (SE) or insufficient effort (IE) according to various MMPI-2 scale cutoffs. After “pruning” of an initial, complex classification tree, the Response Bias Scale (RBS) took precedence in classifying cognitive effort. After removing RBS from the model, Hy took precedence in classifying IE. The present findings provide MMPI-2 scores that may be associated with SE and IE among civil litigants and claimants, in addition to illustrating the complexity with which MMPI-2 scores and effort test results are associated in the litigation context. (JINS, 2008, 14, 842–852.)
Subthalamic stimulation affects homophone meaning generation in Parkinson's disease
Authors: CASTNER JOANNA E. , COPLAND DAVID A. , SILBURN PETER A. , COYNE TERRY J. , SINCLAIR FELICITY , CHENERY HELEN J.
Published: September 2008

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) in individuals with Parkinson's disease (PD) has often been associated with reduced verbal fluency performance. This study aimed to directly assess semantic switching as a function of STN stimulation in PD participants with the Homophone Meaning Generation Test (HMGT). Seventeen participants with PD who had received STN DBS completed the HMGT in on and off stimulation conditions. Twenty-one non-neurologically impaired participants acted as controls. PD participants (in both on and off stimulation conditions) generated significantly fewer meanings than control participants and consistent with the previous reports of verbal fluency impairment, PD participants produced fewer definitions in the on stimulation condition. PD participants (in both on and off stimulation conditions) also had greater difficulty generating definitions for nonhomographic homophones compared with homographic homographs. The results of this study indicate that STN stimulation exacerbates impairment in semantic switching. (JINS, 2008, 14, 890–894.)
Cerebellar pathology does not impair performance on identification or categorization tasks
Authors: ELL SHAWN W. , IVRY RICHARD B.
Published: September 2008

In comparison to the basal ganglia, prefrontal cortex, and medial temporal lobes, the cerebellum has been absent from recent research on the neural substrates of categorization and identification, two prominent tasks in the learning and memory literature. To investigate the contribution of the cerebellum to these tasks, we tested patients with cerebellar pathology (seven with bilateral degeneration, six with unilateral lesions, and two with midline damage) on rule-based and information-integration categorization tasks and an identification task. In rule-based tasks, it is assumed that participants learn the categories through an explicit reasoning process. In information-integration tasks, optimal performance requires the integration of information from multiple stimulus dimensions, and participants are typically unaware of the decision strategy. The identification task, in contrast, required participants to learn arbitrary, color-word associations. The cerebellar patients performed similar to matched controls on all three tasks and performance did not vary with the extent of cerebellar pathology. Although the interpretation of these null results requires caution, these data contribute to the current debate on cerebellar contributions to cognition by providing boundary conditions on understanding the neural substrates of categorization and identification, and help define the functional domain of the cerebellum in learning and memory. (JINS, 2008, 14, 760–770.)
Executive function and metacognitive self-awareness after Severe Traumatic Brain Injury
Authors: BIVONA UMBERTO , CIURLI PAOLA , BARBA CARMEN , ONDER GRAZIANO , AZICNUDA EVA , SILVESTRO DANIELA , MANGANO RENATA , RIGON JESSICA , FORMISANO RITA
Published: September 2008

The objective of this study is to identify the clinical, neuropsychological, neuropsychiatric, and functional variables that correlate with metacognitive self-awareness (SA) in severe traumatic brain injury (TBI) outpatients and to assess the influence of the same variables on the sensory-motor, cognitive, and behavioral-affective indicators of SA. This cross-sectional observational study evaluated 37 outpatients from May 2006 to June 2007 in a neurorehabilitation hospital on the basis of the following inclusion criteria: (1) age ≥ 15 years; (2) diagnosis of severe TBI (Glasgow Coma Scale, GCS ≤ 8); (3) posttraumatic amnesia (PTA) resolution; (4) capacity to undergo formal psychometric evaluation despite cognitive and sensory-motor deficits; (5) absence of aphasia; (6) availability of informed consent. A neuropsychological battery was used to evaluate attention, memory, and executive functions. SA was assessed by the awareness questionnaire (AQ), administered to both patients and relatives. Decreased metacognitive self-awareness is significantly correlated with increased problems in some components of executive system, even when the AQ subscales were considered separately. The significant correlation found between some components of executive system and metacognitive self-awareness confirmed the importance of addressing this issue to treat SA contextually in the rehabilitation of executive functions. (JINS, 2008,14, 862–868.)
Patterns of memory: A normative taxonomy of the Wide Range Assessment of Memory and Learning – Second Edition (WRAML-2)
Authors: ATKINSON THOMAS M. , KONOLD TIMOTHY R. , GLUTTING JOSEPH J.
Published: September 2008

Memory is arguably the most important function of cognition. When left undetected, memory impairments are linked to life long underachievement and negative social consequences. Given that the construct of memory is multidimensional, the current study examined patterns of multiple indicators associated with memory across individuals ranging in age from 5 to 85 years who had been administered the Wide Range Assessment of Memory and Learning – Second Edition (WRAML-2). Multistage cluster analysis with independent age replications was used to empirically identify normative profiles in a sample of (n= 1172) typically developing individuals. This procedure considered how various indicators of memory operate in concert by accounting for the nonlinear multivariate relationships among them. Results supported nine common (or core) profile types that satisfied all formal heuristic and statistical criteria, including complete coverage, satisfactory within-type homogeneity, between-type dissimilarity, and replicability. A summary of the defining characteristics for each profile is provided. (JINS, 2008,14, 869–877.)
Composite scores for executive function items: Demographic heterogeneity and relationships with quantitative magnetic resonance imaging
Authors: CRANE PAUL K. , NARASIMHALU KAAVYA , GIBBONS LAURA E. , PEDRAZA OTTO , MEHTA KALA M. , TANG YUXIAO , MANLY JENNIFER J. , REED BRUCE R. , MUNGAS DAN M.
Published: September 2008

Accurate neuropsychological assessment of older individuals from heterogeneous backgrounds is a major challenge. Education, ethnicity, language, and age are associated with scale level differences in test scores, but item level bias might contribute to these differences. We evaluated several strategies for dealing with item and scale level demographic influences on a measure of executive abilities defined by working memory and fluency tasks. We determined the impact of differential item functioning (DIF). We compared composite scoring strategies on the basis of their relationships with volumetric magnetic resonance imaging (MRI) measures of brain structure. Participants were 791 Hispanic, white, and African American older adults. DIF had a salient impact on test scores for 9% of the sample. MRI data were available on a subset of 153 participants. Validity in comparison with structural MRI was higher after scale level adjustment for education, ethnicity/language, and gender, but item level adjustment did not have a major impact on validity. Age adjustment at the scale level had a negative impact on relationships with MRI, most likely because age adjustment removes variance related to age-associated diseases. (JINS, 2008,14, 746–759.)
Temperature finestructure in the Indonesian Seas
Authors: Ffield Amy , Robertson Robin
Published: September 2008

Twenty‐one years of eXpendable BathyThermograph temperature profile data are used to examine the spatial and temporal variability in finestructure throughout the Indonesian Seas region. Finestructure is the variation of vertical properties on scales from several meter to tens of meter thickness, and is associated, for example, with internal wave activity, an evolving system that can be a precursor to turbulent vertical mixing. As might be expected, on average, the highest temperature finestructure values are observed within 5 km of the shelf‐slope boundary, especially within straits, and the lowest values at distances greater than 35 km. However, the long‐period time variability in the temperature finestructure reveals significant, unexpected, depth‐dependent monsoonal and interannual modulations. In the upper 100 m, there is a 63% enhancement in the temperature finestructure during the windy Southeast Monsoon months of June, July, and August (in particular during La Niña years), relative to the low‐wind intermonsoon months of September, October, and November (in particular during El Niño years). Below 100 m, the monsoon influence is much reduced, but surprisingly significant interannual temperature finestructure variability is observed down to 600‐m depth with a signal opposite to that in the upper layer of the ocean: a 6‐month lagged 13% enhancement associated with El Niño relative to La Niña time periods between 100‐ and 600‐m depths. These results provide a background framework in which to interpret modeling and observational vertical mixing studies in the Indonesian Seas region.
Structure of an MHD‐scale Kelvin‐Helmholtz vortex: Two‐dimensional two‐fluid simulations including finite electron inertial effects
Authors: Nakamura T. K. M. , Fujimoto M. , Otto A.
Published: September 2008

Our two‐dimensional two‐fluid simulations including finite electron inertial effects of an MHD‐scale Kelvin‐Helmholtz (KH) vortex show that the plasma mixing and transport across the Earth's tail‐magnetopause during northward interplanetary magnetic field (IMF) conditions can be caused by the coupling between the KH vortex and magnetic reconnection. First, it is found by systematical two‐dimensional simulations under various fundamental conditions that two types of magnetic reconnection are driven in a KH vortex that are crucial factors for determining the structure of the KH vortex itself. One, named “type I reconnection,” occurs in the case where the magnetic field components along the k vector of Kelvin‐Helmholtz instability (KHI) are antiparallel across the velocity shear layer (antiparallel case). Another, named “type II reconnection,” is driven in the case where the velocity shear is strong enough to produce highly rolled‐up KH vortices and highly stretched field lines therein (strong KHI case). It is also found that type I reconnection leads directly to plasma mixing across the shear layer and that type II reconnection forms magnetic islands and plasma contained in these magnetic islands can be transferred from one side to the other across the shear layer. Next, linear analyses of the Earth's magnetopause‐like cases under northward IMF show that the antiparallel case is obtained rather commonly and also that there is a significant possibility that the strong KHI case may be important. Furthermore, two‐fluid simulations of the magnetopause‐like cases actually show the occurrence of type I and type II reconnection in two dimensions. These results indicate that type I and type II reconnection may play a substantial role in the plasma mixing and transport across the magnetopause.
Observations of the warm plasma cloak and an explanation of its formation in the magnetosphere
Authors: Chappell C. R. , Huddleston M. M. , Moore T. E. , Giles B. L. , Delcourt D. C.
Published: September 2008

Previous studies of the magnetospheric plasma populations have concentrated on the low‐energy (1 eV) plasma of the plasmasphere, the more energetic (1‐100 keV) plasma of the plasma sheet and ring current, and the high‐energy (approximately MeV) plasma of the radiation belts. A compilation of satellite measurements over the past 30 years augmented by recent observations from the Polar‐TIDE instrument has revealed a new perspective on a plasma population in the middle magnetosphere. This population consists of ions with energies of a few eV to greater than several hundred eV which display a characteristic bidirectional field‐aligned pitch angle distribution. Measurements from the ATS, ISEE, SCATHA, DE, and POLAR satellites establish the characteristics of this “warm plasma cloak” of particles that is draped over the nightside region of the plasmasphere and is blown into the morning and early afternoon dayside sector by the sunward convective wind in the magnetosphere. The satellite observations combined with the predictions of an ion trajectory model are used to describe the formation and dynamics of the warm plasma cloak.
Lateral circulation and suspended sediment transport in a curved estuarine channel: Winyah Bay, SC, USA
Authors: Kim Yong Hoon , Voulgaris George
Published: September 2008

Shipborne vertical profiles of flow and suspended sediment concentration collected on a transect, across a curved, nonsymmetrical estuarine channel are presented. Analysis of the transient cross‐channel momentum balance equation shows that the lateral circulation pattern is controlled by the interaction between centrifugal and lateral baroclinic forcings although those two might not be necessarily in balance as suggested earlier by Seim and Gregg (1997). Instead, differential along‐channel advection and local acceleration appear to influence greatly lateral circulation dynamics. During ebb when the water column is highly stratified, the interaction between centrifugal acceleration and opposite‐directed lateral baroclinic forcing results in weak lateral flows. During flood, lateral flows are dominated by centrifugal acceleration, which is directed toward the outside of the curvature at the mid‐depth because of the nonlogarithmic current profile, and reinforced by lateral baroclinic forcing. This results in strong two‐layer clockwise circulation (looking up‐estuary) during flood. The eastward‐directed bottom currents during ebb deliver only a small amount of suspended sediment from the relatively narrow western shoal to the channel bed. During flood, the west‐directed near‐bed currents deliver a significant amount of sediments from the gentle, broad eastern shoal, which in conjunction with the locally resuspended sediment load promotes the development of the estuarine turbidity maximum. Increased lateral advection of sediments during flood reinforces a tidal asymmetry in the development of turbidity maximum. Decomposition analysis of lateral sediment fluxes averaged over a tidal cycle suggests convergence of sediment toward the center of the channel is driven mainly by the oscillatory tidal component.
Modeling of vortex ripple morphodynamics
Authors: Marieu V. , Bonneton P. , Foster D. L. , Ardhuin F.
Published: September 2008

A new morphology module has been developed in order to perform simulations of the bed form evolution under hydrodynamic forcing. This module has been implemented into the numerical model Dune2D, which solves the Reynolds Averaged Navier‐Stokes (RANS) equations in the boundary layer and resolves sediment transport over moving sand beds. The morphology module is composed of a modified central scheme and a routine that simulates avalanches and has been successfully applied to the study of orbital ripples evolution. Ripple growth from a quasiflat bed have been simulated, and the growth behavior has been compared to previous experimental measurements. The simulated ripples reach an equilibrium state where energy damping processes (avalanches) compensate energy production processes (flux of sediment). These processes have been analyzed during ripple creation, growth, merging, and annihilation. Furthermore, sandy bed evolutions have been simulated with random initial bed forms in order to examine the influence of the bed “history” on the final solution and the wave energy dissipated during these evolutions.
Brazilian Analog for Ancient Marine Environments on Mars
Authors: Bridges Nathan T. , Hook Simon J. , Thomson Bradley J. , Crowley James K. , de Souza Filho Carlos Roberto , Macambira Joel B. , de Lima Pereira Silva Gilberto
Published: September 2008

Banded iron formations (BIFs) are iron oxide‐ and silica‐rich chemical sedimentary rocks that were deposited in great abundance during an approximately 800‐million‐year span from the late Archean to the mid‐Proterozoic eons (circa 2.7–1.9 billion years ago). At that time, the terrestrial atmosphere was changing in composition from early anoxic conditions to a more oxygenated state, due possibly to the increasing activity of photosynthetic organisms. It has been suggested that Mars and Earth were more similar in their early history than they are today, and that analogous geologic processes—including those responsible for BIF deposition—may have operated on both planets. Here we discuss BIF samples collected from drill cores at Carajas, Brazil, that represent a variety of fresh, weathered, and altered rocks. Laboratory and remote sensing measurements of these rocks show unique properties that may assist in the discovery of any similar deposits on Mars.
Environmental Legacies of the International Polar Year
Authors: Carlson David , Tin Tina
Published: September 2008

The International Polar Year (IPY) 2007–2008 seems poised to make major advances in polar knowledge and understanding, while leaving a legacy of new or enhanced observational systems, facilities, and infrastructure (see “Status and progress of the International Polar Year,” Eos, 89(34), 19 August 2008). In addition, we hope the IPY will stimulate and leave a positive environmental legacy for polar research and for research generally. In this Forum, we consider the prospects for positive IPY legacies in the forms of reduced environmental impacts of research activities, wise decisions about resource management, and greater internal (within the scientific community) and external (among global citizens) awareness of polar and global environmental issues.
Interdisciplinary Links in Oceanic Spreading Center Systems: Mantle to Microbe: Integrated Studies at Oceanic Spreading Centers; Portland, Oregon, 25–26 March 2008, Mid‐Atlantic Ridge ∼35°–37.5°N Implementation Plan Workshop, Portland, Oregon, 27–28 March 2008
Authors: Phillips Kathleen A. , Blackman Donna K.
Published: September 2008

Ridge 2000 (R2K) is an interdisciplinary research program sponsored by the U.S. National Science Foundation (NSF) that conducts integrated studies on Earth's oceanic spreading centers and hydrothermal vent communities. R2K's scientific community gathered in Oregon for two meetings to discuss recent research results and to consider future coordinated studies.
Radioactive Isotopes as Tracers: A Closer Look at Radium and Radon: Measurement and Application of Radium and Radon Isotopes in Environmental Sciences; Venice, Italy, 7–11 April 2008
Authors: Moore W.
Published: September 2008

The accurate measurement and modeling of certain radium and radon isotopes is important because such radionuclides have become primary tools for determining fluxes of submarine groundwater discharge (SGD) into the ocean, rates of mixing of coastal waters, residence times of water in estuaries, and interactions between surface water and groundwater.

Fifty‐two scientists from 14 countries met for a workshop on radium and radon isotopes, hosted by the Venice office of the U.N. Educational, Scientific, and Cultural Organization (UNESCO). These scientists discussed complexities regarding the measurement of radium‐223 (223Ra), radium‐224 (224Ra), radium‐226 (226Ra), radium‐228 (228Ra), radon‐220 (220Rn), and radon‐222 (222Rn), as well as models used to apply the results to environmental questions.
Clark Receives Ocean Sciences Award
Authors: Roman Michael R. , Clark H. Lawrence
Published: September 2008

H. Lawrence Clark received the 2008 Ocean Sciences Award at the 2008 Ocean Sciences Meeting, held 2–7 March 2008 in Orlando, Fla. The award is given in recognition of outstanding and long‐standing service to the ocean sciences.
The Science and Politics of Global Climate Change: A Guide to the Debate
Authors: Gordon Wendy S.
Published: September 2008

The Science and Politics of Global Climate Change is a fascinating hybrid of science and policy directed at a broad, or nonspecialist, audience that may not be well versed in the ongoing climate change controversy. The authors, scientists at heart who have worked in both academic and political settings, have the necessary background and credentials to write an authoritative primer on the subject. In doing so, they offer the public the opportunity to hear both sides of the debate, review the scientific evidence supporting or refuting competing arguments, and consider policy options in an unbiased presentation. Their fundamental aim is to develop a knowledgeable citizenry equipped to participate in the debate and help shape future climate change policy.
Strong evidence for non‐similar earthquake source scaling in central Italy
Authors: Malagnini Luca , Scognamiglio Laura , Mercuri Alessia , Akinci Aybige , Mayeda Kevin
Published: September 2008

The scaling of earthquakes of the Central Apennines (Italy) is investigated using broadband seismograms from the Colfiorito sequence (4 ≤ MW ≤ 6). Our results are not consistent with self‐similar scaling, and can be described by the following relationship: M0 ∝ fc−(3 + ɛ), where ɛ = 1.7 ± 0.3. We speculate that dynamic fault lubrication by fluid pressurization may be responsible for such extreme behavior, and use our results for the calibration of a weak‐motion‐based predictive relationship for the ground motion (MW ≤ 4.1) up to MW ∼ 6 for this region.
Effect of the altitudinal variation of the gravitational acceleration on the thermosphere simulation
Authors: Deng Yue , Ridley Aaron J. , Wang Wenbin
Published: September 2008

For simplicity, a constant gravitational acceleration () is assumed in many general circulation models (GCMs). To estimate the influence of the altitudinal variation of the on the thermosphere simulation, two runs have been made under the solar maximum condition using the non‐hydrostatic Global Ionosphere Thermosphere Model (GITM), including one with a constant (8.7 m/s2) and the other with an altitude‐dependent . During geomagnetic quiet time, globe averagely, the constant case overestimates the neutral density by 30% and underestimates the temperature by 10% around 120 km altitude compared with the altitude‐dependent gravitation case. A post‐processing then has been done to the constant case by shifting the atmosphere vertically according to the altitude‐dependent . After this shifting, the global average density difference decreases to 10%, and the temperature difference also changes correspondingly to 2% at 120 km. The specification directly causes the vertical shift of the atmosphere through changing the scale height. Meanwhile, it changes the temperature profile, which feeds back to the altitude profile of the neutral density. In order to separate these two effects, three simple tests with one‐dimensional semi‐realistic atmosphere have been conducted, and the primary results are that the vertical shifting and the temperature variation caused by the specification contribute 20% and 25% of the density difference, respectively. This study gives a reference to other GCMs about the validity of the constant gravitational acceleration assumption.
An assessment of remotely sensed land surface temperature
Authors: Trigo Isabel F. , Monteiro Isabel T. , Olesen Folke , Kabsch Ewa
Published: September 2008

The satellite application facility on land surface analysis (Land SAF) generates, archives, and disseminates land surface temperature (LST) in an operational basis. LST is estimated from the spinning enhanced visible and infrared imager (SEVIRI) onboard Meteosat, making use of a generalized split‐windows algorithm. Here SEVIRI LST is compared with retrievals from the moderate resolution imaging spectroradiometer (MODIS), collocated in space and time, for three 10° × 10° areas (Iberian Peninsula, Central Africa, and the Kalahari), and for six 7‐day periods between July 2005 and May 2006. Overall, SEVIRI LSTs are warmer than MODIS values, with maximum discrepancies generally observed for daytime. The mismatches between the two satellite retrievals are then analyzed in terms of (1) satellite viewing angle differences, (2) surface orography, and (3) surface type. Daytime discrepancies are strongly impacted by differential heating rates of elements within a pixel (e.g., vegetation types, bareground), leading to a relatively wide range of MODIS‐SEVIRI LST differences, with strong dependency on the MODIS view zenith angle. In contrast, average nighttime discrepancies are generally below 2°C. The intercomparison between MODIS and SEVIRI LST is complemented with in situ observations taken at Evora ground station (southwestern part of the Iberian Peninsula). The differences between ground and satellite‐derived values show high variability for daytime for both sensors, with a systematic overestimation of in situ values by SEVIRI LST. In the case of nighttime observations, both sensors tend to underestimate local measurements, with estimated bias over all events under study of −1.7°C and −2.6°C for SEVIRI and MODIS LST, respectively.
Refinements to Atlantic basin seasonal hurricane prediction from 1 December
Authors: Klotzbach Philip J.
Published: September 2008

Atlantic basin seasonal hurricane predictions have been issued by the Tropical Meteorology Project at Colorado State University since 1984, with early December forecasts being issued every year since early December 1991. These forecasts have yet to show real‐time forecast skill, despite several statistical models that have shown considerable hindcast skill. In an effort to improve both hindcast skill and hopefully real‐time forecast skill, a modified forecast scheme has been developed using data from 1950 to 2007. Predictors were selected based upon how much variance was explained over the 1950–1989 subperiod. These predictors were then required to explain similar amounts of variance over a latter subperiod from 1990 to 2007. Similar amounts of skill were demonstrated for each of the three predictors selected over the 1950–1989 period, the 1990–2007 period, and the full 1950–2007 period. In addition, significant correlations between individual predictors and physical features known to affect hurricanes during the following August–October (i.e., tropical Atlantic wind shear and sea level pressure changes, ENSO phase changes) were obtained. This scheme uses a new methodology where hindcasts were obtained using linear regression and then ranked to generate final hindcast values. Fifty‐four percent of the variance was explained for seasonal Net Tropical Cyclone (NTC) activity over the 1950–2007 period. These hindcasts show considerable differences in landfalling U.S. tropical cyclones, especially for the Florida Peninsula and East Coast. Seven major hurricanes made Florida Peninsula and East Coast landfall during the top 15 largest NTC hindcasts compared with only two major hurricane landfalls in the bottom 15 smallest NTC hindcasts.
Evidence for the functional significance of diazotroph community structure in soil
Authors: Hsu Shi-Fang , Buckley Daniel H
Published: September 2008

Microbial ecologists continue to seek a greater understanding of the factors that govern the ecological significance of microbial community structure. Changes in community structure have been shown to have functional significance for processes that are mediated by a narrow spectrum of organisms, such as nitrification and denitrification, but in some cases, functional redundancy in the community seems to buffer microbial ecosystem processes. The functional significance of microbial community structure is frequently obscured by environmental variation and is hard to detect in short-term experiments. We examine the functional significance of free-living diazotrophs in a replicated long-term tillage experiment in which extraneous variation is minimized and N-fixation rates can be related to soil characteristics and diazotroph community structure. Soil characteristics were found to be primarily impacted by tillage management, whereas N-fixation rates and diazotroph community structure were impacted by both biomass management practices and interactions between tillage and biomass management. The data suggest that the variation in diazotroph community structure has a greater impact on N-fixation rates than do soil characteristics at the site. N-fixation rates displayed a saturating response to increases in diazotroph community diversity. These results show that the changes in the community structure of free-living diazotrophs in soils can have ecological significance and suggest that this response is related to a change in community diversity.
Transport functions dominate the SAR11 metaproteome at low-nutrient extremes in the Sargasso Sea
Authors: Sowell Sarah M , Wilhelm Larry J , Norbeck Angela D , Lipton Mary S , Nicora Carrie D , Barofsky Douglas F , Carlson Craig A , Smith Richard D , Giovanonni Stephen J
Published: September 2008

The northwestern Sargasso Sea undergoes annual cycles of productivity with increased production in spring corresponding to periods of upwelling, and oligotrophy in summer and autumn, when the water column becomes highly stratified. The biological productivity of this region is reduced during stratified periods as a result of low concentrations of phosphorus and nitrogen in the euphotic zone. To better understand the mechanisms of microbial survival in this oligotrophic environment, we used capillary liquid chromatography (LC)-tandem mass spectrometry to detect microbial proteins in surface samples collected in September 2005. A total of 2215 peptides that mapped to 236 SAR11 proteins, 1911 peptides that mapped to 402 Prochlorococcus proteins and 2407 peptides that mapped to 404 Synechococcus proteins were detected. Mass spectra from SAR11 periplasmic substrate-binding proteins accounted for a disproportionately large fraction of the peptides detected, consistent with observations that these extremely small cells devote a large proportion of their volume to periplasm. Abundances were highest for periplasmic substrate-binding proteins for phosphate, amino acids, phosphonate, sugars and spermidine. Proteins implicated in the prevention of oxidative damage and protein refolding were also abundant. Our findings support the view that competition for multiple nutrients in oligotrophic systems is extreme, but nutrient flux is sufficient to sustain microbial community activity.
Are Eating Occasions and Their Energy Content Related to Child Overweight and Socioeconomic Status?
Authors: Lioret Sandrine , Touvier Mathilde , Lafay Lionel , Volatier Jean‐Luc , Maire Bernard
Published: September 2008

The objectives of this study were: (i) to assess the relationships between childhood overweight (OW) and four eating behaviors: daily eating frequency, and the relative contribution of breakfast, main meals (lunch and dinner), and snacks to total daily energy intake (EI); (ii) to explore whether these eating behaviors are involved in the negative association between socioeconomic status (SES) and OW. A representative sample of French children aged 3–11 years (n = 748) was taken from the 1998–1999 cross‐sectional French INCA1 (Enquête Individuelle et Nationale sur les Consommations Alimentaires) food consumption survey. Food intake was reported in a 7‐day food record, and SES, physical activity, sedentary behavior (SED), weight, and height were reported by answering face‐to‐face questionnaires. After adjusting for EI, physical activity, and SED, OW was positively associated with the contribution of the main meals to EI (P = 0.03), not significantly associated with the contribution of breakfast to EI, and inversely correlated to the number of eating episodes (P = 0.009) and to the contribution of snacking episodes to EI (P = 0.007). Our data suggest that a combination of more frequent intake occasions and lower contribution of the main meals to total daily EI is associated with a smaller risk of OW in children. However, eating frequency was the only eating behavior that played a slight mediation role (contributing ∼8%) in the inverse relationship between SES and OW.
Characterization of coenzyme binding and selectivity determinants in Mycobacterium tuberculosis flavoprotein reductase A: analysis of Arg199 and Arg200 mutants at the NADP(H) 2′-phosphate binding site
Authors: Sabri Muna , Dunford Adrian J. , McLean Kirsty J. , Neeli Rajasekhar , Scrutton Nigel S. , Leys David , Munro Andrew W.
Published: September 2008

Mycobacterium tuberculosis FprA (flavoprotein reductase A) is an NAD(P)H- and FAD-binding reductase that is structurally/evolutionarily related to adrenodoxin reductase. Structural analysis implicates Arg199 and Arg200 in interactions with the NADP(H) 2′-phosphate group. R199A, R200A and R199A/R200A mutants were characterized to explore the roles of these basic residues. All mutations abolished neutral FAD semiquinone stabilization in the NADPH-reduced enzyme, owing to weakened NADPH affinity. Instead, FAD hydroquinone was formed in all mutants, and each displayed substantially enhanced autooxidation rates (20–40-fold) compared with NADPH-reduced WT (wild-type) FprA. Steady-state ferricyanide reduction studies revealed diminished NADPH affinity (higher Km values), but lower NADH Km values. Despite a lowered kcat, the R199A/R200A mutant exhibited a 200-fold coenzyme specificity switch towards NADH, although substrate inhibition was observed at high NADH concentrations (Ki=250 μM). Stopped-flow FAD reduction studies confirmed substantially increased NADPH Kd values, although the limiting flavin reduction rate constant was similar in all mutants. The R199A mutation abolished electron transfer between hydroquinone FprA and NADP+, while this reaction progressed (via an FADH2-NADP+ charge-transfer intermediate) for R200A FprA, albeit more slowly (klim=58.1 s−1 compared with >300 s−1) than in WT. All mutations caused positive shifts in FAD potential (∼40–65 mV). Binding of an NADPH analogue (tetrahydro-NADP) induced negative shifts in potential (∼30–40 mV) only for variants with the R200A mutation, indicating distinctive effects of Arg199/Arg200 on coenzyme binding mode and FAD potential. Collectively, these data reveal important roles for the phylogenetically conserved arginines in controlling FprA FAD environment, thermodynamics, coenzyme selectivity and reactivity.
A complementary metal-oxide-semiconductor compatible monocantilever 12-point probe for conductivity measurements on the nanoscale
Authors: Gammelgaard L. , Bøggild P. , Wells J. W. , Handrup K. , Hofmann Ph. , Balslev M. B. , Hansen J. E. , Petersen P. R. E.
Published: September 2008

We present a complementary metal-oxide-semiconductor compatible, nanoscale 12-point-probe based on TiW electrodes placed on a SiO2 monocantilever. Probes are mass fabricated on Si wafers by a combination of electron beam and UV lithography, realizing TiW electrode tips with a width down to 250nm and a probe pitch of 500nm. In-air four-point measurements have been performed on indium tin oxide, ruthenium, and titanium-tungsten, showing good agreement with values obtained by other four-point probes. In-vacuum four-point resistance measurements have been performed on clean Bi(111) using different probe spacings. The results show the expected behavior for bulk Bi, indicating that the contribution of electronic surface states to the transport properties is very small.
Unsteady flow separation on slip boundaries
Authors: Lekien Francois , Haller George
Published: September 2008

We derive analytic criteria for the location and angle of unsteady particle separation and reattachment in two-dimensional flows with free-slip boundary conditions. Our wall-based criteria show that, in general, fluid breakaway from the boundary takes place at locations different from either instantaneous or averaged stagnation points. Indeed, for time-varying flows, separation does not occur along a free streamline or along an average free streamline. We apply the formula to transport in randomized Rayleigh–Bénard convection cells, as well as to boundary current separation and reattachment in high-frequency radar data collected in Monterey Bay, California.
IUPAC-NIST Solubility Data Series. 86. Ethers and Ketones with Water. Part 5. C6 Ketones with Water
Authors: Góral Marian , Wiśniewska-Gocłowska Barbara
Published: September 2008

The mutual solubilities and related liquid-liquid equilibria of eight binary systems of C6 ketones with water are exhaustively and critically reviewed. Reports of experimental determination of solubility that appeared in the primary literature prior to the middle of 2007 are compiled. For five systems, sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a method based on the evaluation of all experimental data for a given series of ketones was used.
High-order large-eddy simulation of flow over the “Ahmed body” car model
Authors: Minguez M. , Pasquetti R. , Serre E.
Published: September 2008

The structure of the turbulent flow over a simplified automotive model, the Ahmed body (S. R. Ahmed and G. Ramm, SAE Paper No. 8403001, 1984) with a 25° slanted back face, is investigated using high-order large-eddy simulations (LESs) at Reynolds number Re=768000. The numerical approach is carried out with a multidomain spectral Chebyshev–Fourier solver and the bluff body is modeled with a pseudopenalization method. The LES capability is implemented thanks to a spectral vanishing viscosity (SVV) technique, with particular attention to the near wall region. Such a SVV-LES approach is extended for the first time to an industrial three-dimensional turbulent flow over a complex geometry. In order to better understand the interactions between flow separations and the dynamic behavior of the released vortex wake, a detailed analysis of the flow structures is provided. The topology of the flow is well captured showing a partial separation of the boundary layer over the slanted face and the occurrence of two strong contrarotating trailing vortices expanding farther in the wake. The interactions of these large vortices with smaller structures reminiscent of horseshoe vortices, within the shear layer over the slanted face, form large helical structures providing strong unsteady phenomena in the wake. Mean velocity fields and turbulence statistics show a global agreement with the reference experiments of Lienhart et al. (DGLR Fach Symposium der AG SRAB, Stuttgart University, 15–17 November 2000). In order to provide a deeper insight into the nature of turbulence, the flow is analyzed using power spectra and the invariant theory of turbulence of Lumley [Adv. Appl. Mech. 18, 123 (1978)].
IUPAC-NIST Solubility Data Series. 86. Ethers and Ketones with Water. Part 6. C7–C12 Ketones with Water
Authors: Góral Marian , Wiśniewska-Gocłowska Barbara
Published: September 2008

The mutual solubilities and related liquid-liquid equilibria of 25 binary systems of C7–C12 ketones with water are exhaustively and critically reviewed. Reports of experimental determination of solubility that appeared in the primary literature prior to July 2007 are compiled. For 12 systems, sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a method based on the evaluation of all experimental data for a given series of ketones was used. This completes a six-part series of papers which compile and evaluate mutual solubility data of ethers and ketones with water.
Ab initio determination of the electron affinities of DNA and RNA nucleobases
Authors: Roca-Sanjuán Daniel , Merchán Manuela , Serrano-Andrés Luis , Rubio Mercedes
Published: September 2008

High-level quantum-chemical ab initio coupled-cluster and multiconfigurational perturbation methods have been used to compute the vertical and adiabatic electron affinities of the five canonical DNA and RNA nucleobases: uracil, thymine, cytosine, adenine, and guanine. The present results aim for the accurate determination of the intrinsic electron acceptor properties of the isolated nucleic acid bases as described by their electron affinities, establishing an overall set of theoretical reference values at a level not reported before and helping to rule out less reliable theoretical and experimental data and to calibrate theoretical strategies.
Solution processable ionic p-i-n phosphorescent organic light-emitting diodes
Authors: Park Byoungchoo , Han Mi Young , Oh Seung Seok
Published: September 2008

We report efficient light-emission from solution-processed single-layered phosphorescent organic light-emitting diodes (PHOLEDs) that were doped with ionic salt and treated with simultaneous electrical and thermal annealing. Because the simultaneous annealing causes the adsorption of salt ions at the electrode surfaces, the energy levels of the organic molecules are bent by the electric fields due to the adsorbed ions; i.e., the annealing can induce the proper formation of an ionic p-i-n structure. As a result, an ionic p-i-n PHOLED with a peak luminescence of over ∼35000cd∕m2 and a power efficiency of 42lm∕W was achieved through increased and balanced carrier injections.