bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microevolution of Dengue Viruses Circulating among Primary School Children in Kamphaeng Phet, Thailand
Authors: Jarman Richard G. , Holmes Edward C. , Rodpradit Prinyada , Klungthong Chonticha , Gibbons Robert V. , Nisalak Ananda , Rothman Alan L. , Libraty Daniel H. , Ennis Francis A. , Mammen Mammen P. , Endy Timothy P. 
Published: March 2008

ABSTRACT
To determine the extent and structure of genetic variation in dengue viruses (DENV) on a restricted spatial and temporal scale, we sequenced the E (envelope) genes of DENV-1, -2, and -3 isolates collected in 2001 from children enrolled in a prospective school-based study in Kamphaeng Phet, Thailand, and diagnosed with dengue disease. Our analysis revealed substantial viral genetic variation in both time and space, with multiple viral lineages circulating within individual schools, suggesting the frequent gene flow of DENV into this microenvironment. More-detailed analyses of DENV-2 samples revealed strong clustering of viral isolates within individual schools and evidence of more-frequent viral gene flow among schools closely related in space. Conversely, we observed little evolutionary change in those viral isolates sampled over multiple time points within individual schools, indicating a low rate of mutation fixation. These results suggest that frequent viral migration into Kamphaeng Phet, coupled with population (school) subdivision, shapes the genetic diversity of DENV on a local scale, more so than in situ evolution within school catchment areas.
Neuropsychiatric complications of commonly used palliative care drugs
Authors: Jackson N , Doherty J , Coulter S 
Published: March 2008

Abstract
For those facing progressive life limiting disease, symptoms across a range of systems can be problematic. Clinicians may find themselves prescribing from several classes of drugs to alleviate distressing problems and to maximise quality of life for patients. Many drugs used for symptom control in palliative care give rise to neuropsychiatric side effects as they affect the central nervous system either directly or indirectly. The common unwanted effects of these drugs are well known, but there are some important neuropsychiatric effects that physicians are less aware of. If unrecognised, these effects can generate considerable distress and unnecessary harm to patients. We aim to highlight some of the adverse neuropsychiatric effects which occur with commonly used drugs in palliative care. Antiemetics such as metoclopramide and haloperidol can cause significant levels of neuropsychiatric toxicity, as can opiates, antidepressants, anxiolytics and antipsychotics. The syndromes or entities that will be considered are delirium, drug induced parkinsonism, akathisia, serotonin syndrome and neuroleptic malignant syndrome. The intention is to alert clinicians to the iatrogenic complications which may ensue on prescribing drugs commonly used in the palliative care setting.
Incremental predictive value of vascular assessments combined with the Framingham Risk Score for prediction of coronary events in subjects of low–intermediate risk
Authors: Lau K-K , Chan Y-H , Yiu K-H , Tam S , Li S-W , Lau C-P , Tse H-F 
Published: March 2008

Abstract

Background
In patients with low–intermediate risk, the use of the Framingham Risk Score (FRS) may not allow accurate prediction of the occurrence of coronary events.

Objective
To determine whether non-invasive vascular sonographic assessments add value to the FRS for prediction of coronary events.

Methods
Brachial artery flow-mediated dilatation (FMD), carotid intima–media thickness (IMT) and the presence of carotid plaque in 70 male subjects (mean (SD) age 62 (9) years) with a low–intermediate FRS who presented with a recent coronary event were evaluated and compared with those in 35 male controls matched for age (mean age 60 (9) years).

Results
Patients with a recent coronary event had a significantly higher FRS than controls. They had a significantly lower FMD (3.56 (2.41)% vs 5.18 (2.69)%, p = 0.003) and significantly higher prevalence of carotid plaque (67% vs 40%, p = 0.008), but there was no significant difference in mean maximum IMT between the two groups (1.01 (0.28) vs 0.96 (0.14) mm, p = 0.32). Multivariate analysis revealed that FMD ⩽4.75% was an independent predictor of an acute coronary event. Of the three vascular markers, FMD ⩽4.75% and presence of carotid plaque provided the best diagnostic accuracy for a coronary event, with area under the curve (AUC) of 0.70 and 0.64 (p = 0.001 and p = 0.033), respectively, based on receiver operating characteristic curve analysis. Furthermore, incorporating carotid plaque or FMD ⩽4.75% into the FRS (AUC = 0.72 and AUC = 0.78) provided incremental benefit in risk stratification over FRS alone (AUC = 0.66) (p = 0.008 and p = 0.007, for comparison of difference in two receiver operating characteristic curves).

Conclusions
Incorporating a measure of FMD or carotid plaque burden with FRS significantly increases the accuracy of predicting coronary events in subjects of low–intermediate risk and hence should be considered as additional investigations to improve coronary risk assessment.
The Human Thalamus is Crucially Involved in Executive Control Operations
Authors: Marzinzik Frank , Wahl Michael , Schneider Gerd-Helge , Kupsch Andreas , Curio Gabriel , Klostermann Fabian 
Published: March 2008

Abstract
The processing of executive control is thought to involve cortical as well as thalamic brain areas. However, the questions of how thalamic structures contribute to the control of behavior and how cortical versus thalamic processing is coordinated remain to be settled. We therefore aimed at specifying respective activations during the performance of a go/no-go task. To this end, an electroencephalogram was recorded simultaneously from scalp and thalamic electrodes in seven patients undergoing deep brain stimulation. Meanwhile, left- or right-directed precues were presented indicating with which index finger a button press should be putatively executed. Thereafter, 2 sec elapsed until a go or no-go stimulus determined if the prepared movement had to be performed or withheld. In fronto-central scalp as well as in thalamic recordings, event-related potentials upon go versus no-go instructions were expressed differentially. This task effect was unrelated to motor processes and emerged significantly prior at thalamic than at scalp level. Amplitude fluctuations of depth and scalp responses showed site- and task-dependent correlations, particularly between thalamic and no-go-related activities at frontal recording sites. We conclude that an early classification of go and no-go instructions is performed already thalamically. It further appears that this information is subsequently utilized by cortical areas engaged in the definite inhibition of the prepared action.
Left-lateralized N170 Effects of Visual Expertise in Reading: Evidence from Japanese Syllabic and Logographic Scripts
Authors: Maurer Urs , Zevin Jason D. , McCandliss Bruce D. 
Published: March 2008

Abstract
The N170 component of the event-related potential (ERP) reflects experience-dependent neural changes in several forms of visual expertise, including expertise for visual words. Readers skilled in writing systems that link characters to phonemes (i.e., alphabetic writing) typically produce a left-lateralized N170 to visual word forms. This study examined the N170 in three Japanese scripts that link characters to larger phonological units. Participants were monolingual English speakers (EL1) and native Japanese speakers (JL1) who were also proficient in English. ERPs were collected using a 129-channel array, as participants performed a series of experiments viewing words or novel control stimuli in a repetition detection task. The N170 was strongly left-lateralized for all three Japanese scripts (including logographic Kanji characters) in JL1 participants, but bilateral in EL1 participants viewing these same stimuli. This demonstrates that left-lateralization of the N170 is dependent on specific reading expertise and is not limited to alphabetic scripts. Additional contrasts within the moraic Katakana script revealed equivalent N170 responses in JL1 speakers for familiar Katakana words and for Kanji words transcribed into novel Katakana words, suggesting that the N170 expertise effect is driven by script familiarity rather than familiarity with particular visual word forms. Finally, for English words and novel symbol string stimuli, both EL1 and JL1 subjects produced equivalent responses for the novel symbols, and more left-lateralized N170 responses for the English words, indicating that such effects are not limited to the first language. Taken together, these cross-linguistic results suggest that similar neural processes underlie visual expertise for print in very different writing systems.
Autobiographical Memory and Patterns of Brain Atrophy in Fronto-temporal Lobar Degeneration
Authors: McKinnon Margaret C. , Nica Elena I. , Sengdy Pheth , Kovacevic Natasa , Moscovitch Morris , Freedman Morris , Miller Bruce L. , Black Sandra E. , Levine Brian 
Published: March 2008

Abstract
Autobiographical memory paradigms have been increasingly used to study the behavioral and neuroanatomical correlates of human remote memory. Although there are numerous functional neuroimaging studies on this topic, relatively few studies of patient samples exist, with heterogeneity of results owing to methodological variability. In this study, fronto-temporal lobar degeneration (FTLD), a form of dementia affecting regions crucial to autobiographical memory, was used as a model of autobiographical memory loss. We emphasized the separation of episodic (recollection of specific event, perceptual, and mental state information) from semantic (factual information unspecific in time and place) autobiographical memory, derived from a reliable method for scoring transcribed autobiographical protocols, the Autobiographical Interview [Levine, B., Svoboda, E., Hay, J., Winocur, G., & Moscovitch, M. Aging and autobiographical memory: Dissociating episodic from semantic retrieval. Psychology and Aging, 17, 677–689, 2002]. Patients with the fronto-temporal dementia (FTD) and mixed fronto-temporal and semantic dementia (FTD/SD) variants of FTLD were impaired at reconstructing episodically rich autobiographical memories across the lifespan, with FTD/SD patients generating an excess of generic semantic autobiographical information. Patients with progressive nonfluent aphasia were mildly impaired for episodic autobiographical memory, but this impairment was eliminated with the provision of structured cueing, likely reflecting relatively intact medial-temporal lobe function, whereas the same cueing failed to bolster the FTD and FTD/SD patients' performance relative to that of matched comparison subjects. The pattern of episodic, but not semantic, autobiographical impairment was enhanced with disease progression on 1- to 2-year follow-up testing in a subset of patients, supplementing the cross-sectional evidence for specificity of episodic autobiographical impairment with longitudinal data. This behavioral pattern covaried with volume loss in a distributed left-lateralized posterior network centered on the temporal lobe, consistent with evidence from other patient and functional neuroimaging studies of autobiographical memory. Frontal lobe volumes, however, did not significantly contribute to this network, suggesting that frontal contributions to autobiographical episodic memory may be more complex than previously appreciated.
Selective Attention to Affective Value Alters How the Brain Processes Olfactory Stimuli
Authors: Rolls Edmund T. , Grabenhorst Fabian , Margot Christian , da Silva Maria A. A. P. , Velazco Maria Ines 
Published: March 2008

Abstract
How does selective attention to affect influence sensory processing? In a functional magnetic resonance imaging investigation, when subjects were instructed to remember and rate the pleasantness of a jasmin odor, activations were greater in the medial orbito-frontal and pregenual cingulate cortex than when subjects were instructed to remember and rate the intensity of the odor. When the subjects were instructed to remember and rate the intensity, activations were greater in the inferior frontal gyrus. These top-down effects occurred not only during odor delivery but started in a preparation period after the instruction before odor delivery, and continued after termination of the odor in a short-term memory period. Thus, depending on the context in which odors are presented and whether affect is relevant, the brain prepares itself, responds to, and remembers an odor differently. These findings show that when attention is paid to affective value, the brain systems engaged to prepare for, represent, and remember a sensory stimulus are different from those engaged when attention is directed to the physical properties of a stimulus such as its intensity. This differential biasing of brain regions engaged in processing a sensory stimulus depending on whether the cognitive demand is for affect-related versus more sensory-related processing may be an important aspect of cognition and attention. This has many implications for understanding the effects not only of olfactory but also of other sensory stimuli.
Aging Does Not Affect Brain Patterns of Repetition Effects Associated with Perceptual Priming of Novel Objects
Authors: Soldan Anja , Gazes Yunglin , Hilton H. John , Stern Yaakov 
Published: March 2008

Abstract
This study examined how aging affects the spatial patterns of repetition effects associated with perceptual priming of unfamiliar visual objects. Healthy young (n = 14) and elderly adults (n = 13) viewed four repetitions of structurally possible and impossible figures while being scanned with blood oxygenation level-dependent functional magnetic resonance imaging. Although explicit recognition memory for the figures was reduced in the elder subjects, repetition priming did not differ across the two age groups. Using multivariate linear modeling, we found that the spatial networks of regions that demonstrated repetition-related increases and decreases in activity were identical in both age groups, although there was a trend for smaller magnitude repetition effects in these networks in the elder adults for objects that had been repeated thrice. Furthermore, repetition-related reductions in activity in the left inferior frontal cortex for possible objects correlated with repetition-related facilitation in reaction time across both young and elder subjects. Repetition-related increases of an initially negative response were observed for both object types in both age groups in parts of the default network, suggesting that less attention was required for processing repeated stimuli. These findings extend prior studies using verbal and semantic picture priming tasks and support the view that perceptual repetition priming remains intact in later adulthood because the same spatial networks of regions continue to show repetition-related neural plasticity across the adult life span.
Plasticity in the Adult Human Auditory Brainstem following Short-term Linguistic Training
Authors: Song Judy H. , Skoe Erika , Wong Patrick C. M. , Kraus Nina 
Published: March 2008

Abstract
Peripheral and central structures along the auditory pathway contribute to speech processing and learning. However, because speech requires the use of functionally and acoustically complex sounds which necessitates high sensory and cognitive demands, long-term exposure and experience using these sounds is often attributed to the neocortex with little emphasis placed on subcortical structures. The present study examines changes in the auditory brainstem, specifically the frequency following response (FFR), as native English-speaking adults learn to incorporate foreign speech sounds (lexical pitch patterns) in word identification. The FFR presumably originates from the auditory midbrain and can be elicited preattentively. We measured FFRs to the trained pitch patterns before and after training. Measures of pitch tracking were then derived from the FFR signals. We found increased accuracy in pitch tracking after training, including a decrease in the number of pitch-tracking errors and a refinement in the energy devoted to encoding pitch. Most interestingly, this change in pitch-tracking accuracy only occurred in the most acoustically complex pitch contour (dipping contour), which is also the least familiar to our English-speaking subjects. These results not only demonstrate the contribution of the brainstem in language learning and its plasticity in adulthood but also demonstrate the specificity of this contribution (i.e., changes in encoding only occur in specific, least familiar stimuli, not all stimuli). Our findings complement existing data showing cortical changes after second-language learning, and are consistent with models suggesting that brainstem changes resulting from perceptual learning are most apparent when acuity in encoding is most needed.
Prestimulus Cortical Activity is Correlated with Speed of Visuomotor
Processing
Authors: Zhang Yan , Wang Xue , Bressler Steven L. , Chen Yonghong , Ding Mingzhou 
Published: March 2008

Abstract
Response time (RT) is an important behavioral measure of the overall efficacy of sensorimotor processing and is known to vary significantly from trial to trial. Past work on how stimulus evoked cortical responses contribute to RT variability has helped delineate the stages of neuronal information processing. Much less is known about how the state of the brain immediately preceding the stimulus onset (prestimulus) affects RT. We addressed this problem by analyzing data from three macaque monkeys trained to perform a visuomotor pattern discrimination task. Local field potentials were recorded from up to 16 bipolar surface-to-depth electrodes widely distributed over one cerebral hemisphere in each monkey. The degree of linear correlation between RT and prestimulus spectral power was determined over a wide range of frequencies. In the prefrontal cortex, prestimulus power in the beta range (14–30 Hz) was negatively correlated with RT in two monkeys, suggesting a possible role of activity in this frequency range in the mediation of top-down control of visuomotor processing. In the sensorimotor cortex, prestimulus power in the beta range was positively correlated with RT in two monkeys, consistent with the hypothesis that oscillations in this range support the maintenance of steady-state motor output. In visual occipital and temporal lobe areas, prestimulus power in the alpha/low beta range (8–20 Hz) showed positive correlations with RT in three monkeys, possibly reflecting a spatially specific disengagement of visual anticipatory attention. Through measurement of prestimulus spectral coherence, it was further determined that sites showing similar patterns of correlation between spectral power and RT were also linked together in synchronized networks.
Connections between Potential Vorticity Intrusions and Convection in the Eastern Tropical Pacific
Authors: Funatsu Beatriz M. , Waugh Darryn W. 
Published: March 2008

Abstract
The connections between intrusions of stratospheric air into the upper troposphere and deep convection in the tropical eastern Pacific are examined using a combination of data analysis, potential vorticity (PV) inversion, and numerical simulations. Analysis of NCEP–NCAR reanalyses and satellite measurements of outgoing longwave radiation during intrusion events shows increased cloudiness, lower static stability, upward motion, and a buildup of convective available potential energy (CAPE) at the leading edge of the intruding tongue of high PV. Potential inversion inversion calculations show that the upper-level PV makes the dominant contribution to the changes in the quantities that characterize convection. This supports the hypothesis that upper-level PV anomalies initiate and support convection by destabilizing the lower troposphere and causing upward motion ahead on the PV tongue. The dominant role of the upper-level PV is confirmed by simulations using the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5). Convection only occurs when the upper-level PV anomaly is present in the simulations, and the relative contribution of the upper-level PV to changes in the quantities that characterize convection is similar to that inferred from the PV inversion calculations.
Nonlinear Atmospheric Adjustment to Momentum Forcing
Authors: Edson Adam R. , Bannon Peter R. 
Published: March 2008

Abstract
A nonlinear, numerical model of a dry, compressible atmosphere is used to simulate the hydrostatic and geostrophic adjustment to a localized prescribed injection of momentum applied over 5 min. with a size characteristic of an isolated, deep, cumulus cloud. This theoretical study is relevant to the initialization of updrafts in compressible numerical weather prediction models. The four different forcings studied are vertical, divergent horizontal, and nondivergent horizontal momentum forcings, and a prescribed transverse circulation. These forcings are applied to an isothermal atmosphere, a nonisothermal atmosphere, and an atmosphere with a nonisothermal troposphere capped by an isothermal stratosphere. These scenarios are studied by analyzing the resulting perturbation fields and the energetics of the system. Potential vorticity is used to determine the possibility of steady atmospheric states. The energetics of the system are examined to observe the creation and propagation of atmospheric waves. Both traditional and available energetics are used to determine the presence and strength of these waves. Traditional energetics consist of kinetic, internal, and potential energies while available energetics consist of kinetic, available potential, and available elastic energies. The efficiencies are similar for these different energetics, though they represent different phenomena. The traditional energetics show a strong dependence on the presence of a Lamb wave, whereas in the available energetics the Lamb wave has little or no effect.
Singular Vectors and Time-Dependent Normal Modes of a Baroclinic Wave-Mean Oscillation
Authors: Wolfe Christopher L. , Samelson Roger M. 
Published: March 2008

Abstract
Linear disturbance growth is studied in a quasigeostrophic baroclinic channel model with several thousand degrees of freedom. Disturbances to an unstable, nonlinear wave-mean oscillation are analyzed, allowing the comparison of singular vectors and time-dependent normal modes (Floquet vectors). Singular vectors characterize the transient growth of linear disturbances in a specified inner product over a specified time interval and, as such, they complement and are related to Lyapunov vectors, which characterize the asymptotic growth of linear disturbances. The relationship between singular vectors and Floquet vectors (the analog of Lyapunov vectors for time-periodic systems) is analyzed in the context of a nonlinear baroclinic wave-mean oscillation. It is found that the singular vectors divide into two dynamical classes that are related to those of the Floquet vectors. Singular vectors in the “wave dynamical” class are found to asymptotically approach constant linear combinations of Floquet vectors. The most rapidly decaying singular vectors project strongly onto the most rapidly decaying Floquet vectors. In contrast, the leading singular vectors project strongly onto the leading adjoint Floquet vectors. Examination of trajectories that are near the basic cycle show that the leading Floquet vectors are geometrically tangent to the local attractor while the leading initial singular vectors point off the local attractor. A method for recovering the leading Floquet vectors from a small number of singular vectors is additionally demonstrated.