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1

Q-Ball of Inferior Fronto-Occipital Fasciculus and Beyond  

PubMed Central

The inferior fronto-occipital fasciculus (IFOF) is historically described as the longest associative bundle in the human brain and it connects various parts of the occipital cortex, temporo-basal area and the superior parietal lobule to the frontal lobe through the external/extreme capsule complex. The exact functional role and the detailed anatomical definition of the IFOF are still under debate within the scientific community. In this study we present a fiber tracking dissection of the right and left IFOF by using a q-ball residual-bootstrap reconstruction of High-Angular Resolution Diffusion Imaging (HARDI) data sets in 20 healthy subjects. By defining a single seed region of interest on the coronal fractional anisotropy (FA) color map of each subject, we investigated all the pathways connecting the parietal, occipital and posterior temporal cortices to the frontal lobe through the external/extreme capsule. In line with recent post-mortem dissection studies we found more extended anterior-posterior association connections than the “classical” fronto-occipital representation of the IFOF. In particular the pathways we evidenced showed: a) diffuse projections in the frontal lobe, b) fronto-parietal lobes connections trough the external capsule in almost all the subjects and c) widespread connections in the posterior regions. Our study represents the first consistent in vivo demonstration across a large group of individuals of these novel anterior and posterior terminations of the IFOF detailed described only by post-mortem anatomical dissection. Furthermore our work establishes the feasibility of consistent in vivo mapping of this architecture with independent in vivo methodologies. In conclusion q-ball tractography dissection supports a more complex definition of IFOF, which includes several subcomponents likely underlying specific function. PMID:24945305

Amirbekian, Bagrat; Berger, Mitchel S.; Henry, Roland G.

2014-01-01

2

Structural connectivity in a single case of progressive prosopagnosia: the role of the right inferior longitudinal fasciculus.  

PubMed

Progressive prosopagnosia (PP) is a clinical syndrome characterized by a progressive and selective inability to recognize and identify faces of familiar people. Here we report a patient (G.S.) with PP, mainly related to a prominent deficit in recognition of familiar faces, without a semantic (cross-modal) impairment. An in-depth evaluation showed that his deficit extended to other classes of objects, both living and non-living. A follow-up neuropsychological assessment did not reveal substantial changes after about 1 year. Structural MRI showed predominant right temporal lobe atrophy. Diffusion tensor imaging was performed to elucidate structural connectivity of the inferior longitudinal fasciculus (ILF) and the inferior fronto-occipital fasciculus (IFOF), the two major tracts that project through the core fusiform region to the anterior temporal and frontal cortices, respectively. Right ILF was markedly reduced in G.S., while left ILF and IFOFs were apparently preserved. These data are in favour of a crucial role of the neural circuit subserved by right ILF in the pathogenesis of PP. PMID:23099263

Grossi, Dario; Soricelli, Andrea; Ponari, Marta; Salvatore, Elena; Quarantelli, Mario; Prinster, Anna; Trojano, Luigi

2014-07-01

3

The Role of the Arcuate Fasciculus in Conduction Aphasia  

ERIC Educational Resources Information Center

In aphasia literature, it has been considered that a speech repetition defect represents the main constituent of conduction aphasia. Conduction aphasia has frequently been interpreted as a language impairment due to lesions of the arcuate fasciculus (AF) that disconnect receptive language areas from expressive ones. Modern neuroradiological…

Bernal, Byron; Ardila, Alfredo

2009-01-01

4

Reflex vertical gaze and the medial longitudinal fasciculus  

Microsoft Academic Search

Extraocular movements were investigated in a patient with bilateral vascular lesions of the medial longitudinal fasciculus. The patient showed voluntary and reflex horizontal gaze consistent with his lesion, but had absent reflex vertical gaze. Voluntary vertical gaze was present. Necropsy was performed, and the findings suggest that the medial longitudinal fasciculi in the pons conveys impulses for reflex vertical gaze,

L. R. Jenkyn; G. Margolis; A. G. Reeves

1978-01-01

5

Dissecting the uncinate fasciculus: disorders, controversies and a hypothesis  

PubMed Central

The uncinate fasciculus is a bidirectional, long-range white matter tract that connects lateral orbitofrontal cortex and Brodmann area 10 with the anterior temporal lobes. Although abnormalities in the uncinate fasciculus have been associated with several psychiatric disorders and previous studies suggest it plays a putative role in episodic memory, language and social emotional processing, its exact function is not well understood. In this review we summarize what is currently known about the anatomy of the uncinate, we review its role in psychiatric and neurological illnesses, and we evaluate evidence related to its putative functions. We propose that an overarching role of the uncinate fasciculus is to allow temporal lobe-based mnemonic associations (e.g. an individual’s name + face + voice) to modify behaviour through interactions with the lateral orbitofrontal cortex, which provides valence-based biasing of decisions. The bidirectionality of the uncinate fasciculus information flow allows orbital frontal cortex-based reward and punishment history to rapidly modulate temporal lobe-based mnemonic representations. According to this view, disruption of the uncinate may cause problems in the expression of memory to guide decisions and in the acquisition of certain types of learning and memory. Moreover, uncinate perturbation should cause problems that extend beyond memory to include social–emotional problems owing to people and objects being stripped of personal value and emotional history and lacking in higher-level motivational value. PMID:23649697

Von Der Heide, Rebecca J.; Skipper, Laura M.; Klobusicky, Elizabeth

2013-01-01

6

Diffusion Tensor Anisotropy in Adolescents and Adults  

Microsoft Academic Search

We acquired diffusion tensor images on 33 normal adults aged 22–64 and 15 adolescents aged 14–21. We assessed relative anisotropy in stereotaxically located regions of interest in the internal capsule, corpus callosum, anterior thalamic radiations, frontal anterior fasciculus, fronto-occipital fasciculus, temporal lobe white matter, cingulum bundle, frontal inferior longitudinal fasciculus, frontal superior longitudinal fasciculus, and optic radiations. All of these

Jason S. Schneiderman; Monte S. Buchsbaum; M. Mehmet. Haznedar; Erin A. Hazlett; Adam M. Brickman; Lina Shihabuddin; Jesse G. Brand; Yuliya Torosjan; Randall E. Newmark; Cheuk Tang; Jonathan Aronowitz; Reshmi Paul-Odouard; William Byne; Patrick R. Hof

2007-01-01

7

The superior longitudinal fasciculus in typically developing children and adolescents: diffusion tensor imaging and neuropsychological correlates.  

PubMed

The relationship between superior longitudinal fasciculus microstructural integrity and neuropsychological functions were examined in 49 healthy children (range: 5-17 years) using diffusion tensor imaging. Seven major cognitive domains (intelligence, fine-motor, attention, language, visual-spatial, memory, executive function) were assessed. Data analyses used correlational methods. After adjusting for age and gender, fractional anisotropy and axial diffusivity values in the superior longitudinal fasciculus were positively correlated with executive functions of set shifting, whereas left superior longitudinal fasciculus fractional anisotropy values correlated with attention and language. Apparent diffusion coefficient values in the left superior longitudinal fasciculus negatively correlated with inhibitory control. In the left arcuate fasciculus, fractional anisotropy correlated with IQ and attention, whereas radial diffusivity values negatively correlated with IQ, fine-motor skills, and expressive language. Findings from this study provide an examination of the relationship between superior longitudinal fasciculus integrity and children's neuropsychological abilities that can be useful in monitoring pediatric neurologic diseases. PMID:24556549

Urger, Sacide E; De Bellis, Michael D; Hooper, Stephen R; Woolley, Donald P; Chen, Steven D; Provenzale, James

2015-01-01

8

Decoding the superior parietal lobule connections of the superior longitudinal fasciculus/arcuate fasciculus in the human brain.  

PubMed

The temporo-parietal (TP) white matter connections between the inferior parietal lobule and superior temporal gyrus as part of the superior longitudinal fasciculus/arcuate fasciculus (SLF/AF) or middle longitudinal fasciculus (MdLF) have been studied in prior diffusion tensor tractography (DTT) studies. However, few studies have been focusing on the higher TP connections of the superior parietal lobule with the temporal lobe. These higher TP connections have been shown to have a role in core processes such as attention, memory, emotions, and language. Our most recent study, for the first time, hinted to the possibility of a long white matter connection interconnecting the superior parietal lobule (SPL) with the posterior temporal lobe in human brain which we call the SLF/AF TP-SPL and for a shorter abbreviation, the TP-SPL. We decided to further investigate this white matter connection using fiber assignment by continuous tracking deterministic tractography and high spatial resolution diffusion tensor imaging on 3T. Five healthy right-handed men (age range 24-37 years) were studied. We delineated the SPL connections of the SLF/AF TP bilaterally in five normal adult human brains. Using a high resolution DTT technique, we demonstrate for the first time, the trajectory of a long fiber bundle connectivity between the SPL and posterior temporal lobe, called the SLF/AF TP-SPL (or the TP-SPL), bilaterally in five healthy adult human brains. We also demonstrate the trajectory of the vertically oriented posterior TP connections, interconnecting the inferior parietal lobule (IPL) with the posterior temporal lobe (TP-IPL) in relation to the TP-SPL, arcuate fasciculus and other major language pathways. In the current study, for the first time, we categorized the TP connections into the anterior and posterior connectivity groups and subcategorized each one into the SPL or IPL connections. PMID:25086308

Kamali, A; Sair, H I; Radmanesh, A; Hasan, K M

2014-09-26

9

Does the Left Inferior Longitudinal Fasciculus Play a Role in Language? A Brain Stimulation Study  

ERIC Educational Resources Information Center

Although advances in diffusion tensor imaging have enabled us to better study the anatomy of the inferior longitudinal fasciculus (ILF), its function remains poorly understood. Recently, it was suggested that the subcortical network subserving the language semantics could be constituted, in parallel with the inferior occipitofrontal fasciculus, by…

Mandonnet, Emmanuel; Nouet, Aurelien; Gatignol, Peggy; Capelle, Laurent; Duffau, Hugues

2007-01-01

10

Right arcuate fasciculus abnormality in chronic fatigue syndrome.  

PubMed

Purpose To identify whether patients with chronic fatigue syndrome (CFS) have differences in gross brain structure, microscopic structure, or brain perfusion that may explain their symptoms. Materials and Methods Fifteen patients with CFS were identified by means of retrospective review with an institutional review board-approved waiver of consent and waiver of authorization. Fourteen age- and sex-matched control subjects provided informed consent in accordance with the institutional review board and HIPAA. All subjects underwent 3.0-T volumetric T1-weighted magnetic resonance (MR) imaging, with two diffusion-tensor imaging (DTI) acquisitions and arterial spin labeling (ASL). Open source software was used to segment supratentorial gray and white matter and cerebrospinal fluid to compare gray and white matter volumes and cortical thickness. DTI data were processed with automated fiber quantification, which was used to compare piecewise fractional anisotropy (FA) along 20 tracks. For the volumetric analysis, a regression was performed to account for differences in age, handedness, and total intracranial volume, and for the DTI, FA was compared piecewise along tracks by using an unpaired t test. The open source software segmentation was used to compare cerebral blood flow as measured with ASL. Results In the CFS population, FA was increased in the right arcuate fasciculus (P = .0015), and in right-handers, FA was also increased in the right inferior longitudinal fasciculus (ILF) (P = .0008). In patients with CFS, right anterior arcuate FA increased with disease severity (r = 0.649, P = .026). Bilateral white matter volumes were reduced in CFS (mean ± standard deviation, 467 581 mm(3) ± 47 610 for patients vs 504 864 mm(3) ± 68 126 for control subjects, P = .0026), and cortical thickness increased in both right arcuate end points, the middle temporal (T = 4.25) and precentral (T = 6.47) gyri, and one right ILF end point, the occipital lobe (T = 5.36). ASL showed no significant differences. Conclusion Bilateral white matter atrophy is present in CFS. No differences in perfusion were noted. Right hemispheric increased FA may reflect degeneration of crossing fibers or strengthening of short-range fibers. Right anterior arcuate FA may serve as a biomarker for CFS. (©) RSNA, 2014 Online supplemental material is available for this article. PMID:25353054

Zeineh, Michael M; Kang, James; Atlas, Scott W; Raman, Mira M; Reiss, Allan L; Norris, Jane L; Valencia, Ian; Montoya, Jose G

2015-02-01

11

Superior longitudinal fasciculus and language functioning in healthy aging.  

PubMed

Structural deterioration of brain tissue in older adults is thought to be responsible for the majority of age-related cognitive decline. Disruption of widespread cortical networks due to a loss of axonal integrity may also play an important role. Research examining correlations between structural change and functional decline has focused heavily on working memory, processing speed, and executive processes while other aspects of cognition, such as language functioning, have received less attention. The current study aimed to determine whether age-related changes in the superior longitudinal fasciculus (SLF), are responsible for the deterioration in language functioning associated with age. Subjects included 112 right-handed volunteers (ages 19-76). For each subject, the SLF of the left hemisphere was reconstructed from diffusion tensor images (DTI). Mean fractional anisotropy (FA) values were extracted from parietal (SLFp) and temporal (SLFt) bundles. Language functioning was measured using the Peabody Picture Vocabulary Test (PPVT), Boston Naming Test (BNT), Controlled Oral Word Association Test (COWAT), and Semantic Fluency Test (SFT). Regression analyses revealed that males and females showed a different pattern of decline in FA across adulthood. For males, greater SLFt FA was significantly associated with increased COWAT performance, and there was a positive relationship between both age and SLFp FA with BNT scores. In females, greater SLFp FA was related to lower COWAT performance. Taken together, the results suggest that white matter integrity of the SLF follows a different pattern of decline in adulthood for males and females, and this decline differentially affects language functioning. PMID:24680744

Madhavan, Kiely M; McQueeny, Tim; Howe, Steven R; Shear, Paula; Szaflarski, Jerzy

2014-05-01

12

A tractography study in dyslexia: neuroanatomic correlates of orthographic, phonological and speech processing.  

PubMed

Diffusion tensor imaging tractography is a structural magnetic resonance imaging technique allowing reconstruction and assessment of the integrity of three dimensional white matter tracts, as indexed by their fractional anisotropy. It is assumed that the left arcuate fasciculus plays a crucial role for reading development, as it connects two regions of the reading network, the left temporoparietal region and the left inferior frontal gyrus, for which atypical functional activation and lower fractional anisotropy values have been reported in dyslexic readers. In addition, we explored the potential role of the left inferior fronto-occipital fasciculus, which might connect a third region of the reading network, the left ventral occipitotemporal region with the left inferior frontal gyrus. In the present study, 20 adults with dyslexia and 20 typical reading adults were scanned using diffusion tensor imaging, and the bilateral arcuate fasciculus and the left inferior fronto-occipital fasciculus were delineated. Group comparisons show a significantly reduced fractional anisotropy in the left arcuate fasciculus of adults with dyslexia, in particular in the segment that directly connects posterior temporal and frontal areas. This fractional anisotropy reduction might reflect a lower degree of myelination in the dyslexic sample, as it co-occurred with a group difference in radial diffusivity. In contrast, no significant group differences in fractional anisotropy were found in the right arcuate fasciculus or in the left inferior fronto-occipital fasciculus. Correlational analyses (controlled for reading status) demonstrated a specific relation between performance on phoneme awareness and speech perception and the integrity of left arcuate fasciculus as indexed by fractional anisotropy, and between orthographic processing and fractional anisotropy values in left inferior fronto-occipital fasciculus. The present study reveals structural anomalies in the left arcuate fasciculus in adults with dyslexia. This finding corroborates current hypotheses of dyslexia as a disorder of network connections. In addition, our study demonstrates a correlational double dissociation, which might reflect neuroanatomical correlates of the dual route reading model: the left arcuate fasciculus seems to sustain the dorsal phonological route underlying grapheme-phoneme decoding, while the left inferior fronto-occipital fasciculus seems to sustain the ventral orthographic route underlying reading by direct word access. PMID:22327793

Vandermosten, Maaike; Boets, Bart; Poelmans, Hanne; Sunaert, Stefan; Wouters, Jan; Ghesquière, Pol

2012-03-01

13

Am J Psychiatry 159:5, May 2002 813 Uncinate Fasciculus Findings in Schizophrenia  

E-print Network

Am J Psychiatry 159:5, May 2002 813 Article Uncinate Fasciculus Findings in Schizophrenia in schizophrenia. Conventional magnetic resonance imaging (MRI) stud- ies, however, have not shown compelling integ- rity. The first three diffusion tensor imag- ing studies in schizophrenia showed lower

14

Anatomical Properties of the Arcuate Fasciculus Predict Phonological and Reading Skills in Children  

ERIC Educational Resources Information Center

For more than a century, neurologists have hypothesized that the arcuate fasciculus carries signals that are essential for language function; however, the relevance of the pathway for particular behaviors is highly controversial. The primary objective of this study was to use diffusion tensor imaging to examine the relationship between individual…

Yeatman, Jason D.; Dougherty, Robert F.; Rykhlevskaia, Elena; Sherbondy, Anthony J.; Deutsch, Gayle K.; Wandell, Brian A.; Ben-Shachar, Michal

2011-01-01

15

Uncinate fasciculus fiber tracking in mesial temporal lobe epilepsy. Initial findings  

Microsoft Academic Search

In temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS), ictal discharge spread to the frontal and insulo-perisylvian\\u000a cortex is commonly observed. The implication of white matter pathways in this propagation has not been investigated. We compared\\u000a diffusion tensor imaging (DTI) measurements along the uncinate fasciculus (UF), a major tract connecting the frontal and temporal\\u000a lobes, in patients and controls.

S. Rodrigo; C. Oppenheim; F. Chassoux; N. Golestani; Y. Cointepas; C. Poupon; F. Semah; J.-F. Mangin; D. Le Bihan; J.-F. Meder

2007-01-01

16

Evaluating the Arcuate Fasciculus With Combined Diffusion-Weighted MRI Tractography and Electrocorticography  

PubMed Central

The conventional model of language-related brain structure describing the arcuate fasciculus as a key white matter tract providing a direct connection between Wernicke’s region and Broca’s area has been called into question. Specifically, the inferior precentral gyrus, possessing both primary motor (Brodmann Area [BA] 4) and premotor cortex (BA 6), has been identified as a potential alternative termination. The authors initially localized cortical sites involved in language using measurement of event-related gamma-activity on electrocorticography (ECoG). The authors then determined whether language-related sites of the temporal lobe were connected, via white matter structures, to the inferior frontal gyrus more tightly than to the precentral gyrus. The authors found that language-related sites of the temporal lobe were far more likely to be directly connected to the inferior precentral gyrus through the arcuate fasciculus. Furthermore, tractography was a significant predictor of frontal language-related ECoG findings. Analysis of an interaction between anatomy and tractography in this model revealed tractrography to have the highest predictive value for language-related ECoG findings of the precentral gyrus. This study failed to support the conventional model of language-related brain structure. More feasible models should include the inferior precentral gyrus as a termination of the arcuate fasciculus. The exact functional significance of direct connectivity between temporal language-related sites and the precentral gyrus requires further study. PMID:23982893

Brown, Erik C.; Jeong, Jeong-Won; Muzik, Otto; Rothermel, Robert; Matsuzaki, Naoyuki; Juhász, Csaba; Sood, Sandeep; Asano, Eishi

2014-01-01

17

'For the benefit of the people': the Dutch translation of the Fasciculus medicinae, Antwerp 1512.  

PubMed

The article deals with the Dutch translation of the Fasciculus medicinae based on the Latin edition, Venice 1495, with the famous woodcuts created in 1494 for the Italian translation of the original Latin edition of 1491. The woodcuts are compared with the Venetian model. New features in the Antwerp edition include the Skeleton and the Zodiac Man, bot originally based on German models. The text also deals with other woodcuts in the Low Countries based on these Venetian illustrations. The Appendices provide a short title catalog of all the editions and translations based on the Venetian edition and a stemma. PMID:19642255

Coppens, Christian

2009-01-01

18

Damage to the anterior arcuate fasciculus predicts non-fluent speech production in aphasia  

PubMed Central

Non-fluent aphasia implies a relatively straightforward neurological condition characterized by limited speech output. However, it is an umbrella term for different underlying impairments affecting speech production. Several studies have sought the critical lesion location that gives rise to non-fluent aphasia. The results have been mixed but typically implicate anterior cortical regions such as Broca’s area, the left anterior insula, and deep white matter regions. To provide a clearer picture of cortical damage in non-fluent aphasia, the current study examined brain damage that negatively influences speech fluency in patients with aphasia. It controlled for some basic speech and language comprehension factors in order to better isolate the contribution of different mechanisms to fluency, or its lack. Cortical damage was related to overall speech fluency, as estimated by clinical judgements using the Western Aphasia Battery speech fluency scale, diadochokinetic rate, rudimentary auditory language comprehension, and executive functioning (scores on a matrix reasoning test) in 64 patients with chronic left hemisphere stroke. A region of interest analysis that included brain regions typically implicated in speech and language processing revealed that non-fluency in aphasia is primarily predicted by damage to the anterior segment of the left arcuate fasciculus. An improved prediction model also included the left uncinate fasciculus, a white matter tract connecting the middle and anterior temporal lobe with frontal lobe regions, including the pars triangularis. Models that controlled for diadochokinetic rate, picture-word recognition, or executive functioning also revealed a strong relationship between anterior segment involvement and speech fluency. Whole brain analyses corroborated the findings from the region of interest analyses. An additional exploratory analysis revealed that involvement of the uncinate fasciculus adjudicated between Broca’s and global aphasia, the two most common kinds of non-fluent aphasia. In summary, the current results suggest that the anterior segment of the left arcuate fasciculus, a white matter tract that lies deep to posterior portions of Broca’s area and the sensory-motor cortex, is a robust predictor of impaired speech fluency in aphasic patients, even when motor speech, lexical processing, and executive functioning are included as co-factors. Simply put, damage to those regions results in non-fluent aphasic speech; when they are undamaged, fluent aphasias result. PMID:24131592

Guo, Dazhou; Fillmore, Paul; Holland, Audrey; Rorden, Chris

2013-01-01

19

Virtual dissection and comparative connectivity of the superior longitudinal fasciculus in chimpanzees and humans.  

PubMed

Many of the behavioral capacities that distinguish humans from other primates rely on fronto-parietal circuits. The superior longitudinal fasciculus (SLF) is the primary white matter tract connecting lateral frontal with lateral parietal regions; it is distinct from the arcuate fasciculus, which interconnects the frontal and temporal lobes. Here we report a direct, quantitative comparison of SLF connectivity using virtual in vivo dissection of the SLF in chimpanzees and humans. SLF I, the superior-most branch of the SLF, showed similar patterns of connectivity between humans and chimpanzees, and was proportionally volumetrically larger in chimpanzees. SLF II, the middle branch, and SLF III, the inferior-most branch, showed species differences in frontal connectivity. In humans, SLF II showed greater connectivity with dorsolateral prefrontal cortex, whereas in chimps SLF II showed greater connectivity with the inferior frontal gyrus. SLF III was right-lateralized and proportionally volumetrically larger in humans, and human SLF III showed relatively reduced connectivity with dorsal premotor cortex and greater extension into the anterior inferior frontal gyrus, especially in the right hemisphere. These results have implications for the evolution of fronto-parietal functions including spatial attention to observed actions, social learning, and tool use, and are in line with previous research suggesting a unique role for the right anterior inferior frontal gyrus in the evolution of human fronto-parietal network architecture. PMID:25534109

Hecht, Erin E; Gutman, David A; Bradley, Bruce A; Preuss, Todd M; Stout, Dietrich

2015-03-01

20

Pediatric traumatic brain injury: language outcomes and their relationship to the arcuate fasciculus.  

PubMed

Pediatric traumatic brain injury (TBI) may result in long-lasting language impairments alongside dysarthria, a motor-speech disorder. Whether this co-morbidity is due to the functional links between speech and language networks, or to widespread damage affecting both motor and language tracts, remains unknown. Here we investigated language function and diffusion metrics (using diffusion-weighted tractography) within the arcuate fasciculus, the uncinate fasciculus, and the corpus callosum in 32 young people after TBI (approximately half with dysarthria) and age-matched healthy controls (n=17). Only participants with dysarthria showed impairments in language, affecting sentence formulation and semantic association. In the whole TBI group, sentence formulation was best predicted by combined corpus callosum and left arcuate volumes, suggesting this "dual blow" seriously reduces the potential for functional reorganisation. Word comprehension was predicted by fractional anisotropy in the right arcuate. The co-morbidity between dysarthria and language deficits therefore seems to be the consequence of multiple tract damage. PMID:23756046

Liégeois, Frédérique J; Mahony, Kate; Connelly, Alan; Pigdon, Lauren; Tournier, Jacques-Donald; Morgan, Angela T

2013-12-01

21

Disynaptic excitation from the medial longitudinal fasciculus to lumbosacral motoneurons: modulation by repetitive activation, descending pathways, and locomotion  

Microsoft Academic Search

Short-latency excitatory postsynaptic potentials (EPSPs) evoked by stimulation in the medial longitudinal fasciculus (MLF) were recorded intracellularly from motoneurons in the cat lumbosacral spinal cord. Monosynaptic and disynaptic EPSPs occurred in most flexor and extensor motoneurons studied. These EPSPs resulted from the activation of fast (> 100 m\\/s) descending axons from the MLF to the spinal cord. Several features distinguished

M. K. Floeter; G. N. Sholomenko; J.-P. Gossard; R. E. Burke

1993-01-01

22

Is the term "fasciculus opticus cerebralis" more justifiable than the term "optic nerve"?  

PubMed

The terminology of the optic nerve had already been changed three times, since 1895 until 1955 when the term "nervus opticus" was introduced in the "Terminologia Anatomica". Following our study we claim that, from the aspect of phylogenetic evolution of binocular vision development as well as optical embryogenesis where opticus is evidently presented as a product of diencephalic structures, the addition of the term "nervus" to opticus is not adequate and justified. From the clinical aspect the term "nervus opticus" is also inadequate, both as a "nerve" that has no functional regenerative properties, unlike other cranial nerves, as well as from a pedagogical and didactical aspect of educating future physicians. We suggest that the term "Fasciculus Opticus Cerebralis" should be used as it much better explains the origin as well as its affiliation to the central nervous system. PMID:23837214

Vojnikovi?, Bojo; Bajek, Snjezana; Bajek, Goran; Strenja-Lini?, Ines; Grubesi?, Aron

2013-04-01

23

Evidence of Slow Maturation of the Superior Longitudinal Fasciculus in Early Childhood by Diffusion Tensor Imaging  

PubMed Central

While the majority of axonal organization is established by birth in mammalian brains, axonal wiring and pruning processes, as well as myelination, are known to extend to the postnatal periods, where environmental stimuli often play a major role. Normal axonal and myelin development of individual white matter tracts of human in this period is poorly understood and may have a major role in cognitive development of human. In this study, we applied diffusion tensor imaging and normalization-based population analyses to 44 preteen children and 30 adult images. We observed highly significant changes of fiber orientations at regions that correspond to the superior longitudinal fasciculus during the first five years. The result is attributed to slow axonal and/or myelin maturation of this tract, which is believed to be involved in language functions. PMID:17826183

Zhang, Jiangyang; Evans, Alan; Hermoye, Laurent; Lee, Seung-Koo; Wakana, Setsu; Zhang, Weihong; Donohue, Pamela; Miller, Michael I.; Huang, Hao; Wang, Xiaoqing; van Zijl, Peter C.M.; Mori, Susumu

2009-01-01

24

Bilateral agenesis of arcuate fasciculus demonstrated by fiber tractography in congenital bilateral perisylvian syndrome.  

PubMed

Congenital bilateral perisylvian syndrome (CBPS) is a type of cortical developmental abnormality associated with distinctive clinical and imaging features. Clinical spectrum of this syndrome is quite heterogeneous, with different degrees of neurological impairment in affected individuals. High-definition magnetic resonance imaging (MRI) has a great importance in revealing the presence of CBPS, but is limited in elucidating the heterogeneous clinical spectrum. The arcuate fasciculus (AF) is a prominent language tract in the perisylvian region interconnecting Broca and Wernicke areas, and has a high probability of being affected developmentally in CBPS. Herein, we report a case of CBPS with investigation of AF using diffusion tensor imaging (DTI) and fiber tractography in relation to clinical findings. We postulated that proven absence of AF on DTI and fiber tractography would correlate with a severe phenotype of CBPS. PMID:24852949

Kilinc, Ozden; Ekinci, Gazanfer; Demirkol, Ezgi; Agan, Kadriye

2015-03-01

25

Evidence of slow maturation of the superior longitudinal fasciculus in early childhood by diffusion tensor imaging.  

PubMed

While the majority of axonal organization is established by birth in mammalian brains, axonal wiring and pruning processes, as well as myelination, are known to extend to the postnatal periods, where environmental stimuli often play a major role. Normal axonal and myelin development of individual white matter tracts of human in this period is poorly understood and may have a major role in cognitive development of human. In this study, we applied diffusion tensor imaging and normalization-based population analyses to 44 preteen children and 30 adult images. We observed highly significant changes of fiber orientations at regions that correspond to the superior longitudinal fasciculus during the first 5 years. The result is attributed to slow axonal and/or myelin maturation of this tract, which is believed to be involved in language functions. PMID:17826183

Zhang, Jiangyang; Evans, Alan; Hermoye, Laurent; Lee, Seung-Koo; Wakana, Setsu; Zhang, Weihong; Donohue, Pamela; Miller, Michael I; Huang, Hao; Wang, Xiaoqing; van Zijl, Peter C M; Mori, Susumu

2007-11-01

26

Uncinate fasciculus fiber tracking in mesial temporal lobe epilepsy. Initial findings.  

PubMed

In temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS), ictal discharge spread to the frontal and insulo-perisylvian cortex is commonly observed. The implication of white matter pathways in this propagation has not been investigated. We compared diffusion tensor imaging (DTI) measurements along the uncinate fasciculus (UF), a major tract connecting the frontal and temporal lobes, in patients and controls. Ten right-handed patients referred for intractable TLE due to a right HS were investigated on a 1.5-T MR scanner including a DTI sequence. All patients had interictal fluorodeoxyglucose PET showing an ipsilateral temporal hypometabolism associated with insular and frontal or perisylvian hypometabolism. The controls consisted of ten right-handed healthy subjects. UF fiber tracking was performed, and its fractional anisotropy (FA) values were compared between patients and controls, separately for the right and left UF. The left-minus-right FA UF asymmetry index was computed to test for intergroup differences. Asymmetries were found in the control group with right-greater-than-left FA. This asymmetrical pattern was lost in the patient group. Right FA values were lower in patients with right HS versus controls. Although preliminary, these findings may be related to the preferential pathway of seizure spread from the mesial temporal lobe to frontal and insulo-perisylvian areas. PMID:17219141

Rodrigo, S; Oppenheim, C; Chassoux, F; Golestani, N; Cointepas, Y; Poupon, C; Semah, F; Mangin, J-F; Le Bihan, D; Meder, J-F

2007-07-01

27

Detection of the arcuate fasciculus in congenital amusia depends on the tractography algorithm  

PubMed Central

The advent of diffusion magnetic resonance imaging (MRI) allows researchers to virtually dissect white matter fiber pathways in the brain in vivo. This, for example, allows us to characterize and quantify how fiber tracts differ across populations in health and disease, and change as a function of training. Based on diffusion MRI, prior literature reports the absence of the arcuate fasciculus (AF) in some control individuals and as well in those with congenital amusia. The complete absence of such a major anatomical tract is surprising given the subtle impairments that characterize amusia. Thus, we hypothesize that failure to detect the AF in this population may relate to the tracking algorithm used, and is not necessarily reflective of their phenotype. Diffusion data in control and amusic individuals were analyzed using three different tracking algorithms: deterministic and probabilistic, the latter either modeling two or one fiber populations. Across the three algorithms, we replicate prior findings of a left greater than right AF volume, but do not find group differences or an interaction. We detect the AF in all individuals using the probabilistic 2-fiber model, however, tracking failed in some control and amusic individuals when deterministic tractography was applied. These findings show that the ability to detect the AF in our sample is dependent on the type of tractography algorithm. This raises the question of whether failure to detect the AF in prior studies may be unrelated to the underlying anatomy or phenotype. PMID:25653637

Chen, Joyce L.; Kumar, Sukhbinder; Williamson, Victoria J.; Scholz, Jan; Griffiths, Timothy D.; Stewart, Lauren

2015-01-01

28

Recovery of injured arcuate fasciculus in the dominant hemisphere in a patient with an intracerebral hemorrhage.  

PubMed

This study reports on a patient with an intracerebral hemorrhage who showed recovery of an injured arcuate fasciculus (AF) in the dominant hemisphere, using follow-up diffusion tensor tractography. A 43-year-old right-handed man presented with severe aphasia and hemiparesis resulting from a spontaneous intracerebral hemorrhage in the left parietotemporal lobes. The patient showed severe aphasia at 1 month after onset, with an aphasia quotient of 5% on the Korean-Western Aphasia Battery. He underwent comprehensive rehabilitative therapy until 22 months after onset and his aphasia showed improvement, with an aphasia quotient of 58% on the Korean-Western Aphasia Battery. On 1-month diffusion tensor tractography, only the thin ascending part of the left AF from the Wernicke area remained. In contrast, on 16-month diffusion tensor tractography, the injured left AF was thickened and elongated to around the left Broca area; however, discontinuation of the left AF was observed around the left Broca area, and this continuation was elongated to the left Broca area on 22-month diffusion tensor tractography. This study reports on a patient who showed recovery from injury of the left AF along with improvement of aphasia. Recovery of the injured AF in the dominant hemisphere appears to be one of the mechanisms for recovery from aphasia. PMID:25299531

Jang, Sung Ho; Lee, Han Do

2014-12-01

29

Detection of the arcuate fasciculus in congenital amusia depends on the tractography algorithm.  

PubMed

The advent of diffusion magnetic resonance imaging (MRI) allows researchers to virtually dissect white matter fiber pathways in the brain in vivo. This, for example, allows us to characterize and quantify how fiber tracts differ across populations in health and disease, and change as a function of training. Based on diffusion MRI, prior literature reports the absence of the arcuate fasciculus (AF) in some control individuals and as well in those with congenital amusia. The complete absence of such a major anatomical tract is surprising given the subtle impairments that characterize amusia. Thus, we hypothesize that failure to detect the AF in this population may relate to the tracking algorithm used, and is not necessarily reflective of their phenotype. Diffusion data in control and amusic individuals were analyzed using three different tracking algorithms: deterministic and probabilistic, the latter either modeling two or one fiber populations. Across the three algorithms, we replicate prior findings of a left greater than right AF volume, but do not find group differences or an interaction. We detect the AF in all individuals using the probabilistic 2-fiber model, however, tracking failed in some control and amusic individuals when deterministic tractography was applied. These findings show that the ability to detect the AF in our sample is dependent on the type of tractography algorithm. This raises the question of whether failure to detect the AF in prior studies may be unrelated to the underlying anatomy or phenotype. PMID:25653637

Chen, Joyce L; Kumar, Sukhbinder; Williamson, Victoria J; Scholz, Jan; Griffiths, Timothy D; Stewart, Lauren

2015-01-01

30

Individual differences in crossmodal brain activity predict arcuate fasciculus connectivity in developing readers.  

PubMed

Crossmodal integration of auditory and visual information, such as phonemes and graphemes, is a critical skill for fluent reading. Previous work has demonstrated that white matter connectivity along the arcuate fasciculus (AF) is predicted by reading skill and that crossmodal processing particularly activates the posterior STS (pSTS). However, the relationship between this crossmodal activation and white matter integrity has not been previously reported. We investigated the interrelationship of crossmodal integration, both in terms of behavioral performance and pSTS activity, with AF tract coherence using a rhyme judgment task in a group of 47 children with a range of reading abilities. We demonstrate that both response accuracy and pSTS activity for crossmodal (auditory-visual) rhyme judgments was predictive of fractional anisotropy along the left AF. Unimodal (auditory-only or visual-only) pSTS activity was not significantly related to AF connectivity. Furthermore, activity in other reading-related ROIs did not show the same AV-only AF coherence relationship, and AV pSTS activity was not related to connectivity along other language-related tracts. This study is the first to directly show that crossmodal brain activity is specifically related to connectivity in the AF, supporting its role in phoneme-grapheme integration ability. More generally, this study helps to define an interdependent neural network for reading-related integration. PMID:24456399

Gullick, Margaret M; Booth, James R

2014-07-01

31

Sex Differences of Uncinate Fasciculus Structural Connectivity in Individuals with Conduct Disorder  

PubMed Central

Conduct disorder (CD) is one of the most common behavior disorders in adolescents, such as impulsivity, aggression, and running from school. Males are more likely to develop CD than females, and two previous diffusion tensor imaging (DTI) studies have demonstrated abnormal microstructural integrity in the uncinate fasciculus (UF) in boys with CD compared to a healthy control group. However, little is known about changes in the UF in females with CD. In this study, the UF was illustrated by tractography; then, the fractional anisotropy (FA), axial diffusivity, mean diffusion, radial diffusivity (RD), and the length and number of the UF fiber bundles were compared between male and female patients with CD and between female patients with CD and female healthy controls, as well as between males with CD and healthy males. We found that males with CD showed significantly higher FA of the bilateral UF and significantly lower RD of the left UF when comparing with females with CD. Meanwhile, significantly higher FA and lower RD of the bilateral UF were also found in boys with CD relative to the male healthy controls. Our results replicated previous reports that the microstructural integrity of the UF was abnormal in boys with CD. Additionally, our results demonstrated significant gender effects on the UF of patients with CD, which may indicate why boys have higher rates of conduct problems than girls. PMID:24829912

Zhang, Jibiao; Gao, Junling; Shi, Huqing; Huang, Bingsheng; Wang, Xiang; Situ, Weijun; Cai, Weixiong; Yi, Jinyao; Zhu, Xiongzhao; Yao, Shuqiao

2014-01-01

32

Aberrations in the arcuate fasciculus are associated with auditory verbal hallucinations in psychotic and in non-psychotic individuals.  

PubMed

The pathophysiology of auditory verbal hallucinations (AVH) is still unclear. Cognitive as well as electrophysiological studies indicate that a defect in sensory feedback (corollary discharge) may contribute to the experience of AVH. This could result from disruption of the arcuate fasciculus, the major tract connecting frontal and temporo-parietal language areas. Previous diffusion tensor imaging studies indeed demonstrated abnormalities of this tract in schizophrenia patients with AVH. It is, however, difficult to disentangle specific associations with AVH in this patient group as many other factors, such as other positive and negative symptoms, medication or halted education could likewise have affected tract integrity. We therefore investigated AVH in relative isolation and studied a group of non-psychotic individuals with AVH as well as patients with AVH and non-hallucinating matched controls. We compared tract integrity of the arcuate fasiculus and of three other control tracts, between 35 non-psychotic individuals with AVH, 35 schizophrenia patients with AVH, and 36 controls using diffusion tensor imaging and magnetization transfer imaging. Both groups with AVH showed an increase in magnetization transfer ratio (MTR) in the arcuate fasciculus, but not in the other control tracts. In addition, a general decrease in fractional anisotropy (FA) for almost all bundles was observed in the patient group, but not in the non-psychotic individuals with AVH. As increased MTR in the arcuate fasciculus was present in both hallucinating groups, a specific association with AVH seems plausible. Decreases in FA, on the other hand, seem to be related to other disease processes of schizophrenia. PMID:22109992

de Weijer, Antoin D; Neggers, Sebastiaan F W; Diederen, Kelly M S; Mandl, René C W; Kahn, René S; Hulshoff Pol, Hilleke E; Sommer, Iris E

2013-03-01

33

Alterations of natural hand movements after interruption of fasciculus cuneatus in the macaque.  

PubMed

As part of a series of investigations on the control of fine finger movements in the macaque, spontaneous use of the hand in grooming, scratching, and manipulation was observed before and after interruption of fasciculus cuneatus (FC). Videotaped observations were made of four stumptail macaques (Macaca arctoides) living outdoors in social groups. The monkeys were followed for 1 to 3 years postoperatively. For the first 2 weeks following surgery, all monkeys neglected the affected hand and did not use it for support, locomotion, climbing, scratching, foraging, or grooming. Recovery of gross arm and hand movements occurred over a 1- to 3-month period. All the monkeys eventually used the hand for support, climbing, and object manipulation, but fine control of the fingers did not recover. Also, there was an apparent hypotonia of the fingers, imparting a "floppy" appearance to the hand. The animals coped with the loss of fine control by decreasing the frequency of some behaviors, eliminating others, and developing alternative strategies. Exploratory movements that were utilized for investigating the anogenital area or foraging for small food items were eliminated by FC interruption. There were obvious deficits in grip formation and grasp of small food objects (see Glendinning et al., this issue), but effects on similar movements during grooming only became obvious after repeated inspection of videotaped records. Self-scratching and sweeps of the hand in grooming were preserved but altered in form and frequency. The component movements in these behaviors were relatively uncoordinated, and the fingers were splayed (abducted). Often the hand was formed in a rigid posture throughout the sweeping motion, and the fingers did not stroke the skin individually. Frame-by-frame analysis of videotapes revealed that the morphology of the precision grip during grooming, in movements termed "plucks," was permanently altered. Preoperatively, the monkeys kept the index finger and thumb closely apposed and routinely made contact on the distal surfaces of the digits, as has been described for precision grip in humans. Postoperatively, this relationship was altered. The index finger frequently missed the thumb tip and made contact on the proximal part of the phalanx, or missed the thumb altogether. Thus, the dorsal column input is important for proprioceptive guidance of movements that achieve "tactile foveation," when objects or surfaces are actively contacted by the receptive areas of keenest sensitivity (on the fingertips). PMID:1595323

Leonard, C M; Glendinning, D S; Wilfong, T; Cooper, B Y; Vierck, C J

1992-01-01

34

Abnormal Language Pathway in Children with Angelman Syndrome  

PubMed Central

Angelman Syndrome is a genetic disorder characterized by pervasive developmental disability with failure to develop speech. We examined the basis for severe language delay in Angelman Syndrome patients using diffusion tensor imaging. Magnetic Resonance Imaging/diffusion tensor imaging was performed in seven genetically confirmed Angelman Syndrome children (age:70±26 months, five males) and four age-matched controls to investigate the microstructural integrity of arcuate fasciculus and other major association tracts. Six of seven Angelman Syndrome children had unidentifiable left arcuate fasciculus while all controls had identifiable arcuate fasciculus. The right arcuate fasciculus was absent in six of seven Angelman Syndrome children and one of four controls. Diffusion tensor imaging color map suggested aberrant morphology of the arcuate fasciculus region. Other association tracts, including uncinate fasciculus, inferior-fronto-occipital fasciculus, inferior-longitudinal fasciculus, and corticospinal tract, were identifiable but showed decreased fractional anisotropy in Angelman Syndrome children. Increased apparent diffusion coefficient was seen in all tracts except uncinate fasciculus when compared to controls. Angelman Syndrome patients have global impairment of white matter integrity in association tracts, particularly, the arcuate fasciculus which shows severe morphological changes. This could be due to a potential problem with axon guidance during brain development possibly due to loss of UBE3A gene expression. PMID:21481743

Wilson, Benjamin J.; Sundaram, Senthil K.; Huq, AHM; Jeong, Jeong-Won; Halverson, Stacey R.; Behen, Michael E.; Bui, Duy Q.; Chugani, Harry T.

2011-01-01

35

Relations between white matter maturation and reaction time in childhood.  

PubMed

White matter matures with age and is important for the efficient transmission of neuronal signals. Consequently, white matter growth may underlie the development of cognitive processes important for learning, including the speed of information processing. To dissect the relationship between white matter structure and information processing speed, we administered a reaction time task (finger abduction in response to visual cue) to 27 typically developing, right-handed children aged 4 to 13. Magnetoencephalography and Diffusion Tensor Imaging were used to delineate white matter connections implicated in visual-motor information processing. Fractional anisotropy (FA) and radial diffusivity (RD) of the optic radiation in the left hemisphere, and FA and mean diffusivity (MD) of the optic radiation in the right hemisphere changed significantly with age. MD and RD decreased with age in the right inferior fronto-occipital fasciculus, and bilaterally in the cortico-spinal tracts. No age-related changes were evident in the inferior longitudinal fasciculus. FA of the cortico-spinal tract in the left hemisphere and MD of the inferior fronto-occipital fasciculus of the right hemisphere contributed uniquely beyond the effect of age in accounting for reaction time performance of the right hand. Our findings support the role of white matter maturation in the development of information processing speed. PMID:24168858

Scantlebury, Nadia; Cunningham, Todd; Dockstader, Colleen; Laughlin, Suzanne; Gaetz, William; Rockel, Conrad; Dickson, Jolynn; Mabbott, Donald

2014-01-01

36

White matter abnormalities in adolescents with generalized anxiety disorder: a diffusion tensor imaging study  

PubMed Central

Background Previous neuroimaging studies have suggested an abnormal neural circuitry of emotion regulation including the amygdala and prefrontal cortex in both adult and adolescent generalized anxiety disorder (GAD) patients. Aberrant integrity of white matter in this neural circuitry has been verified in adult GAD patients. White matter abnormalities in adolescent GAD patients have not been detected. Methods Twenty-five adolescents with GAD and 24 healthy controls underwent a diffusion tensor imaging scan. Fractional anisotropy (FA) was compared between groups with a voxel-wise Tract-Based Spatial Statistics (TBSS) analysis method. Results Compared with healthy controls, adolescents with GAD showed significantly reduced FA in bilateral uncinate fasciculus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, and corona radiata. Conclusions The findings in the present study suggest a neural basis of emotion dysregulation in adolescent GAD patients. PMID:24528558

2014-01-01

37

Altered integrity of the right arcuate fasciculus as a trait marker of schizophrenia: A sibling study using tractography-based analysis of the whole brain.  

PubMed

Trait markers of schizophrenia aid the dissection of the heterogeneous phenotypes into distinct subtypes and facilitate the genetic underpinning of the disease. The microstructural integrity of the white matter tracts could serve as a trait marker of schizophrenia, and tractography-based analysis (TBA) is the current method of choice. Manual tractography is time-consuming and limits the analysis to preselected fiber tracts. Here, we sought to identify a trait marker of schizophrenia from among 74 fiber tracts across the whole brain using a novel automatic TBA method. Thirty-one patients with schizophrenia, 31 unaffected siblings and 31 healthy controls were recruited to undergo diffusion spectrum magnetic resonance imaging at 3T. Generalized fractional anisotropy (GFA), an index reflecting tract integrity, was computed for each tract and compared among the three groups. Ten tracts were found to exhibit significant differences between the groups with a linear, stepwise order from controls to siblings to patients; they included the right arcuate fasciculus, bilateral fornices, bilateral auditory tracts, left optic radiation, the genu of the corpus callosum, and the corpus callosum to the bilateral dorsolateral prefrontal cortices, bilateral temporal poles, and bilateral hippocampi. Posthoc between-group analyses revealed that the GFA of the right arcuate fasciculus was significantly decreased in both the patients and unaffected siblings compared to the controls. Furthermore, the GFA of the right arcuate fasciculus exhibited a trend toward positive symptom scores. In conclusion, the right arcuate fasciculus may be a candidate trait marker and deserves further study to verify any genetic association. Hum Brain Mapp 36:1065-1076, 2015. © 2014 Wiley Periodicals, Inc. PMID:25366810

Wu, Chen-Hao; Hwang, Tzung-Jeng; Chen, Yu-Jen; Hsu, Yun-Chin; Lo, Yu-Chun; Liu, Chih-Min; Hwu, Hai-Gwo; Liu, Chen-Chung; Hsieh, Ming H; Chien, Yi Ling; Chen, Chung-Ming; Isaac Tseng, Wen-Yih

2015-03-01

38

Uncinate fasciculus microstructure and verbal episodic memory in amyotrophic lateral sclerosis: a diffusion tensor imaging and neuropsychological study.  

PubMed

The present study evaluates the integrity of uncinate fasciculus (UF) and the association between UF microstructure and verbal episodic memory (as one of the cognitive functions linked to UF) in non-demented patients with amyotrophic lateral sclerosis (ALS) using diffusion tensor imaging (DTI). We studied 21 patients with ALS and 11 healthy, demographically-comparable volunteers. Fractional anisotropy, apparent diffusion coefficient, axial and radial diffusivity were the DTI metrics examined. Episodic memory was evaluated with Babcock Story Recall Test and Rey Auditory Verbal Learning Test (RAVLT) for patients; measures of immediate and delayed recall and retention for both tests and sum of words recalled through five learning trials for RAVLT were considered. Patients with ALS showed significant bilateral reduction of axial diffusivity in the UF as compared to controls. Furthermore, there were several significant relations between various DTI metrics (mostly in left hemisphere) and memory measures (specifically for the RAVLT). UF microstructural changes may contribute to ALS-related memory impairment, with word-list learning performance relying more upon the integrity of frontal and temporal connections than memory components associated with story recall. PMID:24190400

Christidi, Foteini; Zalonis, Ioannis; Kyriazi, Stavroula; Rentzos, Michalis; Karavasilis, Efstratios; Wilde, Elisabeth A; Evdokimidis, Ioannis

2014-12-01

39

Quantitative Analysis of Gray and White Matter in Williams Syndrome  

PubMed Central

Williams Syndrome is a developmental disorder with a genetic basis, which results in an uneven cognitive profile with relatively strong language skills and severely impaired visuospatial abilities. To better understand the brain structure underlying this profile, we compared individuals with Williams Syndrome to controls using multimodal neuroimaging data and new analytic methods (diffeomorphic mapping and atlas-based analysis). People with Williams Syndrome had basal ganglia atrophy, while the fusiform, the medium temporal gyri, and the cerebellar cortex were relatively preserved. The right superior longitudinal fasciculus, the left fronto-occipital fasciculus, the caudate, and the cingulum demonstrated increased fractional anisotropy, while the corticospinal tract revealed decreased values. These findings may be linked to the uneven cognitive profile evident in Williams Syndrome. PMID:22410548

Faria, Andreia Vasconcellos; Landau, Barbara; O’Hearn, Kirsten M.; Li, Xin; Jiang, Hangyi; Oishi, Kenichi; Zhang, Jiangyang; Mori, Susumu

2012-01-01

40

Concept Image Revisited  

ERIC Educational Resources Information Center

Concept image and concept definition is an important construct in mathematics education. Its use, however, has been limited to cognitive studies. This article revisits concept image in the context of research on undergraduate students' understanding of the derivative which regards the context of learning as paramount. The literature, mainly on…

Bingolbali, Erhan; Monaghan, John

2008-01-01

41

Revisiting Curriculum Potential  

ERIC Educational Resources Information Center

This article analyzes the notion of curriculum potential by revisiting the ideas of Miriam Ben-Peretz and Joseph Schwab. Invoking the German "Didaktik" tradition and by way of a curriculum-making framework, the paper argues that interpreting curriculum materials for curriculum potential requires a careful analysis and unpacking of the meanings and…

Deng, Zongyi

2011-01-01

42

Colloquial Hebrew Imperatives Revisited  

ERIC Educational Resources Information Center

In revisiting Bolozky's [Bolozky, Shmuel, 1979. "On the new imperative in colloquial Hebrew." "Hebrew Annual Review" 3, 17-24] and Bat-El's [Bat-El, Outi, 2002. "True truncation in colloquial Hebrew imperatives." "Language" 78(4), 651-683] analyses of colloquial Hebrew imperatives, the article argues for restricting Imperative Truncation to the…

Bolozky, Shmuel

2009-01-01

43

Anodic Polarization Curves Revisited  

ERIC Educational Resources Information Center

An experiment published in this "Journal" has been revisited and it is found that the curve pattern of the anodic polarization curve for iron repeats itself successively when the potential scan is repeated. It is surprising that this observation has not been reported previously in the literature because it immediately brings into…

Liu, Yue; Drew, Michael G. B.; Liu, Ying; Liu, Lin

2013-01-01

44

Bohr's Atomic Model Revisited  

Microsoft Academic Search

Bohr's atomic model, its relationship to the radiation spectrum of the hydrogen atom and the inherent hypotheses are revisited. It is argued that Bohr could have adopted a different approach, focusing his analyzes on the stationary orbit of the electron and its decomposition on two harmonic oscillators and then imposing, as actually he did, Planck's quantization for the oscillators' energies.

Francisco Caruso; Vitor Oguri

2009-01-01

45

Technological innovation processes revisited  

Microsoft Academic Search

This work is part of an inquiry into the causes of the small occurrence of innovations in the Brazilian society. It was based on a retrospective analysis of cases experienced by the author, as well as on the study of certain industries. The systemic model of the technological innovation process presented here, while revisiting the models in the literature, emphasizes

Antonio Cantisani

2006-01-01

46

Adolescent hallux valgus revisited.  

PubMed

Treatment of adolescent hallux valgus with first metatarsal double osteotomy is well described in the literature. Unfortunately, first metatarsal phalangeal joint stiffness and deformity recurrence have been reported at relatively high rates. The authors revisit a technique aimed at preventing these complications. PMID:25102495

Marshall, Tyler J; Shung, Joseph R; Khoury, Joseph G

2014-08-01

47

Revisiting the Rhetorical Curriculum  

ERIC Educational Resources Information Center

The aim of the special strand on "Revisiting the rhetorical curriculum" is to explore the educational potential of a new rhetorical perspective, specifically in relation to different traditions within educational and rhetorical studies. This implies that we do not only look at education "in" rhetoric, but that we position education also "as" a…

Rutten, Kris; Soetaert, Ronald

2012-01-01

48

The Linguistic Repertoire Revisited  

ERIC Educational Resources Information Center

This article argues for the relevance of poststructuralist approaches to the notion of a linguistic repertoire and introduces the notion of language portraits as a basis for empirical study of the way in which speakers conceive and represent their heteroglossic repertoires. The first part of the article revisits Gumperz's notion of a linguistic…

Busch, Brigitta

2012-01-01

49

Diffusion Tensor MR Imaging Reveals Persistent White Matter Alteration after Traumatic Brain Injury Experienced during Early Childhood  

PubMed Central

BACKGROUND AND PURPOSE Diffusion tensor imaging (DTI) can noninvasively quantify white matter (WM) integrity. Although its application in adult traumatic brain injury (TBI) is common, few studies in children have been reported. The purposes of this study were to examine the alteration of fractional anisotropy (FA) in children with TBI experienced during early childhood and to quantify the association between FA and injury severity. MATERIALS AND METHODS FA was assessed in 9 children with TBI (age = 7.89 ± 1.00 years; Glasgow Coma Scale [GCS] = 10.11 ± 4.68) and a control group of 12 children with orthopedic injuries without central nervous system involvement (age = 7.51 ± 0.95 years). All of the subjects were at minimum 12 months after injury. We examined group differences in a series of predetermined WM regions of interest with t test analysis. We subsequently conducted a voxel-wise comparison with Spearman partial correlation analysis. Correlations between FA and injury severity were also calculated on a voxel-wise basis. RESULTS FA values were significantly reduced in the TBI group in genu of corpus callosum (CC), posterior limb of internal capsule (PLIC), superior longitudinal fasciculus (SLF), superior fronto-occipital fasciculus (SFO), and centrum semiovale (CS). GCS scores were positively correlated with FA in several WM areas including CC, PLIC, SLF, CS, SFO, and inferior fronto-occipital fasciculus (IFO). CONCLUSION This DTI study provides evidence that WM integrity remains abnormal in children with moderate-to-severe TBI experienced during early childhood and that injury severity correlated strongly with FA. PMID:17905895

Yuan, W.; Holland, S.K.; Schmithorst, V.J.; Walz, N.C.; Cecil, K.M.; Jones, B.V.; Karunanayaka, P.; Michaud, L.; Wade, S.L.

2014-01-01

50

Bohr's atomic model revisited  

E-print Network

Bohr's atomic model, its relationship to the radiation spectrum of the hydrogen atom and the inherent hypotheses are revisited. It is argued that Bohr could have adopted a different approach, focusing his analyzes on the stationary orbit of the electron and its decomposition on two harmonic oscillators and then imposing, as actually he did, Planck's quantization for the oscillators' energies. Some consequences of this procedure are examined.

Caruso, Francisco

2008-01-01

51

Bohr's atomic model revisited  

E-print Network

Bohr's atomic model, its relationship to the radiation spectrum of the hydrogen atom and the inherent hypotheses are revisited. It is argued that Bohr could have adopted a different approach, focusing his analyzes on the stationary orbit of the electron and its decomposition on two harmonic oscillators and then imposing, as actually he did, Planck's quantization for the oscillators' energies. Some consequences of this procedure are examined.

Francisco Caruso; Vitor Oguri

2008-06-03

52

Downbeat nystagmus associated with damage to the medial longitudinal fasciculus of the pons: a vestibular balance control mechanism via the lower brainstem paramedian tract neurons.  

PubMed

The paramedian tract (PMT) neurons, a group of neurons associated with eye movement that project into the cerebellar flocculus, are present in or near the medial longitudinal fasciculus (MLF) in the paramedian region of the lower brainstem. A 66-year-old man with multiple sclerosis in whom downbeat nystagmus appeared along with right MLF syndrome due to a unilateral pontomedullary lesion is described. In light of these findings, a possible schema for the vestibular balance control mechanism circuit of the PMT neurons via the flocculus is presented. Damage to the PMT neurons impaired the elective inhibitory control mechanism of the anterior semicircular canal neural pathway by the flocculus. This resulted in the appearance of anterior semicircular canal-dominant vestibular imbalance and the formation of downbeat nystagmus. From the pathogenesis of this vertical vestibular nystagmus, the action of the PMT neurons in the vestibular eye movement neuronal pathway to maintain vestibular balance was conjectured to be as follows. PMT neurons transmit vestibular information from the anterior semicircular canals to the cerebellum, forming a cerebellum/brainstem feedback loop. Vestibular information from that loop is integrated in the cerebellum, inhibiting only the anterior semicircular canal neuronal pathway via the flocculus and controlling vestibular balance. PMID:23510567

Nakamagoe, Kiyotaka; Fujizuka, Natsu; Koganezawa, Tadachika; Yamaguchi, Tetsuto; Tamaoka, Akira

2013-05-15

53

Differences in the right inferior longitudinal fasciculus but no general disruption of white matter tracts in children with autism spectrum disorder  

PubMed Central

One of the most widely cited features of the neural phenotype of autism is reduced “integrity” of long-range white matter tracts, a claim based primarily on diffusion imaging studies. However, many prior studies have small sample sizes and/or fail to address differences in data quality between those with autism spectrum disorder (ASD) and typical participants, and there is little consensus on which tracts are affected. To overcome these problems, we scanned a large sample of children with autism (n = 52) and typically developing children (n = 73). Data quality was variable, and worse in the ASD group, with some scans unusable because of head motion artifacts. When we follow standard data analysis practices (i.e., without matching head motion between groups), we replicate the finding of lower fractional anisotropy (FA) in multiple white matter tracts. However, when we carefully match data quality between groups, all these effects disappear except in one tract, the right inferior longitudinal fasciculus (ILF). Additional analyses showed the expected developmental increases in the FA of fiber tracts within ASD and typical groups individually, demonstrating that we had sufficient statistical power to detect known group differences. Our data challenge the widely claimed general disruption of white matter tracts in autism, instead implicating only one tract, the right ILF, in the ASD phenotype. PMID:24449864

Koldewyn, Kami; Yendiki, Anastasia; Weigelt, Sarah; Gweon, Hyowon; Julian, Joshua; Richardson, Hilary; Malloy, Caitlin; Saxe, Rebecca; Fischl, Bruce; Kanwisher, Nancy

2014-01-01

54

Case Series: Fractional Anisotropy Along the Trajectory of Selected White Matter Tracts in Adolescents Born Preterm With Ventricular Dilation  

PubMed Central

This case series assesses white matter microstructure in 3 adolescents born preterm with nonshunted ventricular dilation secondary to intraventricular hemorrhage. Subjects (ages 12–17 years, gestational age 26–29 weeks, birth weight 825–1624 g) were compared to 3 full-term controls (13–17 years, 39–40 weeks, 3147–3345 g) and 3 adolescents born preterm without ventricular dilatation (10–13 years, 26–29 weeks, 630–1673 g). Tractography using a 2 region of interest method reconstructed the following white matter tracts: superior longitudinal/arcuate fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, and corticospinal tract. Subjects showed increased fractional anisotropy and changes in the pattern of fractional anisotropy along the trajectory of tracts adjacent to the lateral ventricles. Tensor shape at areas of increased fractional anisotropy demonstrated increased linear anisotropy at the expense of planar and spherical anisotropy. These findings suggest increased axonal packing density and straightening of fibers secondary to ventricular enlargement. PMID:22859695

Myall, Nathaniel J.; Yeom, Kristen W.; Yeatman, Jason D.; Gaman-Bean, Shayna; Feldman, Heidi M.

2014-01-01

55

``Robinson's sum rule'' revisited  

NASA Astrophysics Data System (ADS)

This discussion revisits two articles on synchrotron radiation damping published in 1958, one by this author and Evgeny K. Tarasov [Zh. Eksp. Teor. Fiz. 34, 651 (1958)ZETFA70044-4510; Sov. Phys. JETP 34, 449 (1958)SPHJAR0038-5646], and one by Kenneth W. Robinson [Phys. Rev. 111, 373 (1958)PHRVAO0031-899X10.1103/PhysRev.111.373]. The latter is the source of what is known as “Robinson’s sum rule.” Both present the familiar rule, but with very different proofs and calculations of concrete damping decrements. Comparative analysis of these differences reveals serious flaws in Robinson’s proof and calculations.

Orlov, Yuri F.

2010-02-01

56

Reframing in dentistry: revisited.  

PubMed

The successful practice of dentistry involves a good combination of technical skills and soft skills. Soft skills or communication skills are not taught extensively in dental schools and it can be challenging to learn and at times in treating dental patients. Guiding the child's behavior in the dental operatory is one of the preliminary steps to be taken by the pediatric dentist and one who can successfully modify the behavior can definitely pave the way for a life time comprehensive oral care. This article is an attempt to revisit a simple behavior guidance technique, reframing and explain the possible psychological perspectives behind it for better use in the clinical practice. PMID:24021326

Nuvvula, Sivakumar; Kamatham, Rekalakshmi; Challa, Ramasubbareddy; Asokan, Sharath

2013-01-01

57

Multicomponent diffusion revisited  

NASA Astrophysics Data System (ADS)

The derivation of the multicomponent diffusion law is revisited. Following Furry [Am. J. Phys. 16, 63 (1948)], Williams [Am. J. Phys. 26, 467 (1958); Combustion Theory, 2nd ed. (Benjamin/Cummings , Menlo Park, CA,1985)] heuristically rederived the classical kinetic theory results using macroscopic equations, and pointed out that the dynamics of the mixture fluid had been assumed inviscid. This paper generalizes the derivation, shows that the inviscid assumption can easily be relaxed to add a new term to the classical diffusion law, and the thermal diffusion term can also be easily recovered. The nonuniqueness of the multicomponent diffusion coefficient matrix is emphasized and discussed.

Lam, S. H.

2006-07-01

58

Origin and neurochemical properties of bulbospinal neurons projecting to the rat lumbar spinal cord via the medial longitudinal fasciculus and caudal ventrolateral medulla  

PubMed Central

Bulbospinal systems (BS) originate from various regions of the brainstem and influence spinal neurons by classical synaptic and modulatory mechanisms. Our aim was to determine the brainstem locations of cells of origin of BS pathways passing through the medial longitudinal fasciculus (MLF) and the caudal ventrolateral medulla (CVLM). We also examined the transmitter content of spinal terminations of the CVLM pathway. Six adult rats received Fluorogold (FG) injections to the right intermediate gray matter of the lumbar cord (L1–L2) and the b-subunit of cholera toxin (CTb) was injected either into the MLF or the right CVLM (3 animals each). Double-labeled cells were identified within brainstem structures with confocal microscopy and mapped onto brainstem diagrams. An additional 3 rats were injected with CTb in the CVLM to label axon terminals in the lumbar spinal cord. Double-labeled cells projecting via the MLF or CVLM were found principally in reticular regions of the medulla and pons but small numbers of cells were also located within the midbrain. CVLM projections to the lumbar cord were almost exclusively ipsilateral and concentrated within the intermediate gray matter. Most (62%) of terminals were immunoreactive for the vesicular glutamate transporter 2 while 23% contained the vesicular GABA transporter. The inhibitory subpopulation was glycinergic, GABAergic or contained both transmitters. The proportions of excitatory and inhibitory axons projecting via the CVLM to the lumbar cord are similar to those projecting via the MLF. Unlike the MLF pathway, CVLM projections are predominantly ipsilateral and concentrated within intermediate gray but do not extend into motor nuclei or laminia VIII. Terminations of the CVLM pathway are located in a region of the gray matter that is rich in premotor interneurons; thus its primary function may be to coordinate activity of premotor networks. PMID:24808828

Huma, Zilli; Du Beau, Amy; Brown, Christina; Maxwell, David J.

2014-01-01

59

New insights in the limbic modulation of visual inputs: The role of the inferior longitudinal fasciculus and the Li-Am bundle.  

PubMed

Recent anatomical and DTI data demonstrated new aspects in the subcortical occipito-temporal connections. Although a direct (inferior longitudinal fasciculus, ILF) pathway has been previously described, its fine description is still matter of debate. Moreover, a fast and direct subcortical connection between the limbic system and the occipital lobe has been previously recognized in many functional studies but it still remains poorly documented by anatomical images. We provided for the first time an extensive and detailed anatomical description of the ILF subcortical segmentation. We dissected four human hemispheres with modified Klingler's technique, from the basal to the lateral occipito-temporal surface in the two steps, tracking the ILF fibers until their cortical termination. Pictures of this direct temporo-occipital pathway are discussed in the light of recent literature regarding anatomy and functions of occipito-temporal areas. The dissection confirmed the classical originating branches of ILF and allowed a fine description of two main subcomponent of this bundle, both characterized by separate hierarchical distribution: a dorsal ILF and a ventral ILF. Moreover, a direct pathway between lingual cortex and amygdala, not previously demonstrated, is here described with anatomical images. Even if preliminary in results, this is the first fine description of ILF's subcomponents. The complex but clearly segregated organization of the fibers of this bundle (dILF and vILF) supports different level of functions mediated by visual recognition. Moreover, the newly described direct pathway from lingual to amygdala (Li-Am), seems involved in the limbic modulation of visual processing, so it may support physiological conditions the crucial role of this connection in human social cognition. In pathological conditions, on the other hand, this may be one of the hyperactivated pathways in temporo-occipital epileptic and nonepileptic syndromes. PMID:25323099

Latini, Francesco

2015-01-01

60

Not on speaking terms: hallucinations and structural network disconnectivity in schizophrenia.  

PubMed

Auditory verbal hallucinations (AVH) in schizophrenia have previously been associated with functional deficiencies in language networks, specifically with functional disconnectivity in fronto-temporal connections in the left hemisphere and in interhemispheric connections between frontal regions. Here, we investigate whether AVH are accompanied by white matter abnormalities in tracts connecting the frontal, parietal and temporal lobes, also engaged during language tasks. We combined diffusion tensor imaging with tract-based spatial statistics and found white matter abnormalities in patients with schizophrenia as compared with healthy controls. The patients showed reduced fractional anisotropy bilaterally: in the anterior thalamic radiation (ATR), body of the corpus callosum (forceps minor), cingulum, temporal part of the superior longitudinal fasciculus (SLF) and a small area in the inferior fronto-occipital fasciculus (IFOF); and in the right hemisphere: in the visual cortex, forceps major, body of the corpus callosum (posterior parts) and inferior parietal cortex. Compared to patients without current hallucinations, patients with hallucinations revealed decreased fractional anisotropy in the left IFOF, uncinate fasciculus, arcuate fasciculus with SLF, corpus callosum (posterior parts-forceps major), cingulate, corticospinal tract and ATR. The severity of hallucinations correlated negatively with white matter integrity in tracts connecting the left frontal lobe with temporal regions (uncinate fasciculus, IFOF, cingulum, arcuate fasciculus anterior and long part and superior long fasciculus frontal part) and in interhemispheric connections (anterior corona radiata). These findings support the hypothesis that hallucinations in schizophrenia are accompanied by a complex pattern of white matter alterations that negatively affect the language, emotion and attention/perception networks. PMID:24185461

?ur?i?-Blake, Branislava; Nanetti, Luca; van der Meer, Lisette; Cerliani, Leonardo; Renken, Remco; Pijnenborg, Gerdina H M; Aleman, André

2015-01-01

61

Internet Governance revisited: Think decentralization!  

E-print Network

Internet Governance revisited: Think decentralization! Brown-bag presentation given at the National Administration of the core technical resources of the Internet: ICANN: The mission... ,,preserving the public trust by enhancing the operational stability, reliability, security, and global interoperability

Schweik, Charles M.

62

Neuroanatomical Abnormalities and Cognitive Impairments Are Shared by Adults with Attention-Deficit/Hyperactivity Disorder and Their Unaffected First-Degree Relatives  

PubMed Central

Background Attention-deficit/hyperactivity disorder (ADHD) is a highly heritable neurodevelopmental disorder, yet the search for genes with a definitive role in its etiology has been elusive. Deconstructing the disorder in its endophenotypic traits, where the variance is thought to be associated with a fewer number of genes, should boost the statistical power of molecular genetic studies and clarify the pathophysiology of ADHD. In this study, we tested for neuroanatomical and cognitive endophenotypes in a group of adults with ADHD, their unaffected first-degree relatives, and typically developing control subjects. Methods Sixty participants, comprising 20 adults with ADHD, 20 unaffected first-degree relatives, and 20 typically developing control subjects matched for age and gender undertook structural magnetic resonance imaging scans. Voxel-based morphometry with DARTEL was performed to obtain regional gray and white matter volumes. General linear analyses of the volumes of brain regions, adjusting for age and total intracranial volume, were used to compare groups. Sustained attention and response inhibition were also investigated as cognitive endophenotypes. Results Neuroanatomical abnormalities in gray matter volume in the right inferior frontal gyrus and white matter volume in the caudal portion of the right inferior fronto-occipital fasciculus were shared between ADHD probands and their unaffected first-degree relatives. In addition, impairments in sustained attention were also found to be shared between ADHD patients and their relatives. Conclusions Cognitive impairments in sustained attention and neuroanatomical abnormalities in the right inferior frontal gyrus and the posterior part of right inferior fronto-occipital fasciculus are putative neurocognitive endophenotypes in adult ADHD. PMID:24199662

Pironti, Valentino Antonio; Lai, Meng-Chuan; Müller, Ulrich; Dodds, Chris Martin; Suckling, John; Bullmore, Edward Thomas; Sahakian, Barbara Jacquelyn

2014-01-01

63

Delineation of Early and Later Adult Onset Depression by Diffusion Tensor Imaging  

PubMed Central

Background Due to a lack of evidence, there is no consistent age of onset to define early onset (EO) versus later onset (LO) major depressive disorder (MDD). Fractional anisotropy (FA), derived from diffusion tensor imaging (DTI), has been widely used to study neuropsychiatric disorders by providing information about the brain circuitry, abnormalities of which might facilitate the delineation of EO versus LO MDD. Method In this study, 61 pairs of untreated, non-elderly, first-episode MDD patients and healthy controls (HCs) aged 18–45 years old received DTI scans. The voxel-based analysis method (VBM), classification analysis, using the Statistical Package for the Social Sciences (SPSS), and regression analyses were used to determine abnormal FA clusters and their correlations with age of onset and clinical symptoms. Results Classification analysis suggested in the best model that there were two subgroups of MDD patients, delineated by an age of onset of 30 years old, by which MDD patients could be divided into EO (18–29 years old) and LO (30–45 years old) groups. LO MDD was characterized by decreased FA, especially in the white matter (WM) of the fronto-occipital fasciculus and posterior limb of internal capsule, with a negative correlation with the severity of depressive symptoms; in marked contrast, EO MDD showed increased FA, especially in the WM of the corpus callosum, corticospinal midbrain and inferior fronto-occipital fasciculus, while FA of the WM near the midbrain had a positive correlation with the severity of depressive symptoms. Conclusion Specific abnormalities of the brain circuitry in EO vs. LO MDD were delineated by an age of onset of 30 years old, as demonstrated by distinct abnormal FA clusters with opposite correlations with clinical symptoms. This DTI study supported the evidence of an exact age for the delineation of MDD, which could have broad multidisciplinary importance. Trial Registration ClinicalTrials.gov NCT00703742 PMID:25393297

Yu, Hongjun; Nie, Binbin; Li, Na; Luo, Chunrong; Li, Haijun; Liu, Fang; Bai, Yan; Shan, Baoci; Xu, Lin; Xu, Xiufeng

2014-01-01

64

White matter microstructure and the variable adult outcome of childhood attention deficit hyperactivity disorder.  

PubMed

Changes in cerebral cortical anatomy have been tied to the clinical course of attention deficit hyperactivity disorder (ADHD). We now ask if alterations in white matter tract microstructure are likewise linked with the adult outcome of childhood ADHD. Seventy-five young adults, 32 with ADHD persisting from childhood and 43 with symptom remission were contrasted against 74 never-affected comparison subjects. Using diffusion tensor imaging, we defined fractional anisotropy, a metric related to white matter microstructure, along with measures of diffusion perpendicular (radial) and parallel (axial) to the axon. Analyses were adjusted for head motion, age and sex, and controlled for multiple comparisons and medication history. Tract-based analyses showed that greater adult inattention, but not hyperactivity-impulsivity, was associated with significantly lower fractional anisotropy in the left uncinate (standardized ?=-0.37, t=3.28, p=0.002) and inferior fronto-occipital fasciculi (standardized ?=-0.37, t=3.29, p=0.002). The ADHD group with symptoms persisting into adulthood had significantly lower fractional anisotropy than the never-affected controls in these tracts, differences associated with medium to large effect sizes. By contrast, the ADHD group that remitted by adulthood did not differ significantly from controls. The anomalies were found in tracts that connect components of neural systems pertinent to ADHD, such as attention control (inferior fronto-occipital fasciculus) and emotion regulation and the processing of reward (the uncinate fasciculus). Change in radial rather than axial diffusivity was the primary driver of this effect, suggesting pathophysiological processes including altered myelination as future targets for pharmacological and behavioral interventions. PMID:25241803

Shaw, Philip; Sudre, Gustavo; Wharton, Amy; Weingart, Daniel; Sharp, Wendy; Sarlls, Joelle

2015-02-01

65

FROST: Revisited and Distributed Vincent Poirriez  

E-print Network

FROST: Revisited and Distributed Vincent Poirriez LAMIH UVHC,UMR CNRS 8530 59313 Valenciennes de la Recherche FROST: Revisited and Distributed Vincent Poirriez HICOMB'05:April 04, 2005 #12;Protein Threading Problem Associate a protein sequence to an already known 3D structure. FROST: Revisited

Singer, Daniel

66

Bulgarian ergonomics revisited.  

PubMed

In his earlier and more intensive review of ergonomics in Bulgaria, the author concluded that this discipline was highly developed and enjoyed strong government support. It was found that the network of ergonomics activities across national, regional, and local industrial plant levels was perhaps the most highly organised and comprehensive extension of ergonomics concerns of any country in the world. The brief revisit described in this report revealed that ergonomics continues to enjoy a very high measure of respectability. As also noted earlier, the field of ergonomics is still largely the province of physiologists and engineers. Some psychologists that are associated with design organisations are involved in ergonomics activities but, for the most part, psychologists deal primarily with more traditional topics that fall under the heading of industrial or work psychology. PMID:15676425

Seminara, J L

1982-03-01

67

Revisiting the schism.  

PubMed

The schism between medicine and public health has deep historical roots. The Rockefeller Foundation's Clinical Epidemiology program, initiated in the late 1970s, was seen by Kerr White, its director, as the means to heal the schism. This article revisits the role that the Foundation played in creating that schism before reviewing post-World War II efforts on the part of both the Foundation and the World Health Organization to incorporate the teaching of preventive medicine in medical education curricula. White labeled these efforts as failures, but a closer look at the history raises questions concerning what evidence he used to make this judgment and whether clinical epidemiology has not instead widened the gap between cure and prevention. PMID:25626230

Litsios, Socrates

2014-01-01

68

Polite Theories Revisited  

NASA Astrophysics Data System (ADS)

The classic method of Nelson and Oppen for combining decision procedures requires the theories to be stably-infinite. Unfortunately, some important theories do not fall into this category (e.g. the theory of bit-vectors). To remedy this problem, previous work introduced the notion of polite theories. Polite theories can be combined with any other theory using an extension of the Nelson-Oppen approach. In this paper we revisit the notion of polite theories, fixing a subtle flaw in the original definition. We give a new combination theorem which specifies the degree to which politeness is preserved when combining polite theories. We also give conditions under which politeness is preserved when instantiating theories by identifying two sorts. These results lead to a more general variant of the theorem for combining multiple polite theories.

Jovanovi?, Dejan; Barrett, Clark

69

Satellite failures revisited  

NASA Astrophysics Data System (ADS)

In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.

Balcerak, Ernie

2012-12-01

70

Revisiting Lambert's problem  

NASA Astrophysics Data System (ADS)

The orbital boundary value problem, also known as Lambert problem, is revisited. Building upon Lancaster and Blanchard approach, new relations are revealed and a new variable representing all problem classes, under L-similarity, is used to express the time of flight equation. In the new variable, the time of flight curves have two oblique asymptotes and they mostly appear to be conveniently approximated by piecewise continuous lines. We use and invert such a simple approximation to provide an efficient initial guess to an Householder iterative method that is then able to converge, for the single revolution case, in only two iterations. The resulting algorithm is compared, for single and multiple revolutions, to Gooding's procedure revealing to be numerically as accurate, while having a significantly smaller computational complexity.

Izzo, Dario

2015-01-01

71

Clinical correlations of microstructural changes in progressive supranuclear palsy.  

PubMed

In patients with progressive supranuclear palsy (PSP), previous reports have shown a severe white matter (WM) damage involving supra and infratentorial regions including cerebellum. In the present study, we investigated potential correlations between WM integrity loss and clinical-cognitive features of patients with PSP. By using magnetic resonance imaging and diffusion tensor imaging with tract based spatial statistic analysis, we analyzed WM volume in 18 patients with PSP and 18 healthy controls (HCs). All patients and HCs underwent a detailed clinical and neuropsychological evaluation. Relative to HCs, patients with PSP showed WM changes encompassing supra and infratentorial areas such as corpus callosum, fornix, midbrain, inferior fronto-occipital fasciculus, anterior thalamic radiation, superior cerebellar peduncle, superior longitudinal fasciculus, uncinate fasciculus, cingulate gyrus, and cortico-spinal tract bilaterally. Among different correlations between motor-cognitive features and WM structural abnormalities, we detected a significant association between fronto-cerebellar WM loss and executive cognitive impairment in patients with PSP. Our findings, therefore, corroborate the hypothesis that cognitive impairment in PSP may result from both "intrinsic" and "extrinsic" frontal lobe dysfunction, likely related to cerebellar disconnection. PMID:24786632

Tessitore, Alessandro; Giordano, Alfonso; Caiazzo, Giuseppina; Corbo, Daniele; De Micco, Rosa; Russo, Antonio; Liguori, Sara; Cirillo, Mario; Esposito, Fabrizio; Tedeschi, Gioacchino

2014-10-01

72

Cortico-cortical, cortico-striatal, and cortico-thalamic white matter fiber tracts generated in the macaque brain via dynamic programming.  

PubMed

Probabilistic methods have the potential to generate multiple and complex white matter fiber tracts in diffusion tensor imaging (DTI). Here, a method based on dynamic programming (DP) is introduced to reconstruct fibers pathways whose complex anatomical structures cannot be resolved beyond the resolution of standard DTI data. DP is based on optimizing a sequentially additive cost function derived from a Gaussian diffusion model whose covariance is defined by the diffusion tensor. DP is used to determine the optimal path between initial and terminal nodes by efficiently searching over all paths, connecting the nodes, and choosing the path in which the total probability is maximized. An ex vivo high-resolution scan of a macaque hemi-brain is used to demonstrate the advantages and limitations of DP. DP can generate fiber bundles between distant cortical areas (superior longitudinal fasciculi, arcuate fasciculus, uncinate fasciculus, and fronto-occipital fasciculus), neighboring cortical areas (dorsal and ventral banks of the principal sulcus), as well as cortical projections to the hippocampal formation (cingulum bundle), neostriatum (motor cortical projections to the putamen), thalamus (subcortical bundle), and hippocampal formation projections to the mammillary bodies via the fornix. Validation is established either by comparison with in vivo intracellular transport of horseradish peroxidase in another macaque monkey or by comparison with atlases. DP is able to generate known pathways, including crossing and kissing tracts. Thus, DP has the potential to enhance neuroimaging studies of cortical connectivity. PMID:23879573

Ratnanather, J Tilak; Lal, Rakesh M; An, Michael; Poynton, Clare B; Li, Muwei; Jiang, Hangyi; Oishi, Kenichi; Selemon, Lynn D; Mori, Susumu; Miller, Michael I

2013-01-01

73

Genome-wide schizophrenia variant at MIR137 does not impact white matter microstructure in healthy participants.  

PubMed

A single nucleotide polymorphism (SNP rs1625579) within the micro-RNA 137 (MIR137) gene recently achieved strong genome-wide association with schizophrenia (SZ). However, the mechanisms by which SZ risk may be mediated by this variant are unknown. As miRNAs have the potential to influence oligodendrocyte development, we investigated whether this SNP was associated with variability in white matter (WM) microstructure. Diffusion tensor imaging (DTI) was conducted on 123 healthy participants genotyped for rs1625579. The analysis consisted of whole-brain tract-based spatial statistics and atlas-based tractography analysis of six major WM tracts known to be affected in SZ - the inferior longitudinal fasciculus, the uncinate fasciculus, the inferior fronto-occipital fasciculus, the anterior thalamic radiation, the cingulum bundle and the corpus callosum. No significant differences in either whole-brain fractional anisotropy or mean diffusivity between MIR137 genotype groups were observed (p>0.05). Similarly, atlas-based tractography of particular tracts implicated in SZ failed to reveal any significant differences between MIR137 genotype groups on measures of WM connectivity (p>0.05). In the absence of WM effects comparable to those reported for other SZ associated genes, these data suggest that MIR137 alone may not confer variability in these WM measures and therefore may not act in isolation for any effects that the variant may have on WM microstructure in SZ samples. PMID:24820543

Kelly, Sinead; Morris, Derek W; Mothersill, Omar; Rose, Emma Jane; Fahey, Ciara; O'Brien, Carol; O'Hanlon, Erik; Gill, Michael; Corvin, Aiden P; Donohoe, Gary

2014-06-27

74

Dark Energy Perturbations Revisited  

E-print Network

In this paper we study the evolution of cosmological perturbations in the presence of dynamical dark energy, and revisit the issue of dark energy perturbations. For a generally parameterized equation of state (EoS) such as w_D(z) = w_0+w_1\\frac{z}{1+z}, (for a single fluid or a single scalar field ) the dark energy perturbation diverges when its EoS crosses the cosmological constant boundary w_D=-1. In this paper we present a method of treating the dark energy perturbations during the crossing of the $w_D=-1$ surface by imposing matching conditions which require the induced 3-metric on the hypersurface of w_D=-1 and its extrinsic curvature to be continuous. These matching conditions have been used widely in the literature to study perturbations in various models of early universe physics, such as Inflation, the Pre-Big-Bang and Ekpyrotic scenarios, and bouncing cosmologies. In all of these cases the EoS undergoes a sudden change. Through a detailed analysis of the matching conditions, we show that \\delta_D an...

Li, Mingzhe; Li, Hong; Brandenberger, Robert; Zhang, Xinmin

2010-01-01

75

Great magnetic storms revisited  

NASA Astrophysics Data System (ADS)

In this work we revisit a very important topic of space weather the great magnetic storms Our inspiration comes from the work done by Tsurutani et al GRL 1992 in which 5 Dst -250nT geomagnetic storms were studied in terms mainly of their interplanetary origin Since 1996 the post-SOHO era we have identified a number of 18 Dst -200nT events this time with a much more complete set of observations of the sun and of the near-earth space We use data from the Large Angle and Spectrometric Coronagraph and the Extreme Ultraviolet Imaging Telescope both aboard the Solar and Heliospheric Observatory to identify the solar origin of these events Solar wind and interplanetary magnetic field from the Advanced Composition Explorer are used to study these events in terms of their interplanetary structure We also address the high energy cosmic ray modulation caused by these events using ground-based muon observations from telescope installed at the Southern Space Observatory Brazil

Dal Lago, A.; Gonzalez, W. D.; Echer, E.; Vieira, L. E. A.; Guarnieri, F. L.; Clua de Gonzalez, A. L.; da Silva, M. R.; de Lucas, A.; Schuch, N. J.

76

Revisiting caspases in sepsis  

PubMed Central

Sepsis is a life-threatening illness that occurs due to an abnormal host immune network which extends through the initial widespread and overwhelming inflammation, and culminates at the late stage of immunosupression. Recently, interest has been shifted toward therapies aimed at reversing the accompanying periods of immune suppression. Studies in experimental animals and critically ill patients have demonstrated that increased apoptosis of lymphoid organs and some parenchymal tissues contributes to this immune suppression, anergy and organ dysfunction. Immediate to the discoveries of the intracellular proteases, caspases for the induction of apoptosis and inflammation, and their striking roles in sepsis have been focused elaborately in a number of original and review articles. Here we revisited the different aspects of caspases in terms of apoptosis, pyroptosis, necroptosis and inflammation and focused their links in sepsis by reviewing several recent findings. In addition, we have documented striking perspectives which not only rewrite the pathophysiology, but also modernize our understanding for developing novel therapeutics against sepsis. PMID:25412304

Aziz, M; Jacob, A; Wang, P

2014-01-01

77

Searle's"Dualism Revisited"  

SciTech Connect

A recent article in which John Searle claims to refute dualism is examined from a scientific perspective. John Searle begins his recent article 'Dualism Revisited' by stating his belief that the philosophical problem of consciousness has a scientific solution. He then claims to refute dualism. It is therefore appropriate to examine his arguments against dualism from a scientific perspective. Scientific physical theories contain two kinds of descriptions: (1) Descriptions of our empirical findings, expressed in an every-day language that allows us communicate to each other our sensory experiences pertaining to what we have done and what we have learned; and (2) Descriptions of a theoretical model, expressed in a mathematical language that allows us to communicate to each other certain ideas that exist in our mathematical imaginations, and that are believed to represent, within our streams of consciousness, certain aspects of reality that we deem to exist independently of their being perceived by any human observer. These two parts of our scientific description correspond to the two aspects of our general contemporary dualistic understanding of the total reality in which we are imbedded, namely the empirical-mental aspect and the theoretical-physical aspect. The duality question is whether this general dualistic understanding of ourselves should be regarded as false in some important philosophical or scientific sense.

P., Henry

2008-11-20

78

Moment tensor decompositions revisited  

NASA Astrophysics Data System (ADS)

The decomposition of moment tensors into isotropic (ISO), double-couple (DC) and compensated linear vector dipole (CLVD) components is a tool for classifying and physically interpreting seismic sources. Since an increasing quantity and quality of seismic data allow inverting for accurate moment tensors and interpreting details of the source process, an efficient and physically reasonable decomposition of moment and source tensors is necessary. In this paper, the most common moment tensor decompositions are revisited, new equivalent formulas of the decompositions are derived, suitable norms of the moment tensors are discussed and the properties of commonly used source-type plots are analysed. The Hudson skewed diamond plot is introduced in a much simpler way than originally proposed. It is shown that not only the Hudson plot but also the diamond CLVD-ISO plot and the Riedesel-Jordan plot conserve the uniform distribution probability of moment eigenvalues if the appropriate norm of moment tensors is applied. When analysing moment tensor uncertainties, no source-type plot is clearly preferable. Since the errors in the eigenvectors and eigenvalues of the moment tensors cannot be easily separated, the moment tensor uncertainties project into the source-type plots in a complicated way. As a consequence, the moment tensors with the same uncertainties project into clusters of a different size. In case of an anisotropic focal area, the complexity of moment tensors of earthquakes prevents their direct interpretation, and the decomposition of moment tensors must be substituted by that of the source tensors.

Vavry?uk, Václav

2015-01-01

79

The "Mushroom Cloud" Demonstration Revisited  

ERIC Educational Resources Information Center

A revisitation of the classical "mushroom cloud" demonstration is described. Instead of aniline and benzoyl peroxide, the proposed reaction involves household chemicals such as alpha-pinene (turpentine oil) and trichloroisocyanuric acid ("Trichlor") giving an impressive demonstration of oxidation and combustion reactions that…

Panzarasa, Guido; Sparnacci, Katia

2013-01-01

80

Common Knowledge Revisited Ronald Fagin  

E-print Network

that in order for something to be a convention, it must in fact be common knowledge among the members of a group means "go" and red means "stop" is presumably common knowledge among the drivers in our society.) CommonCommon Knowledge Revisited Ronald Fagin IBM Almaden Research Center 650 Harry Road San Jose, CA

Halpern, Joseph Y.

81

Oxidative phosphorylation revisited.  

PubMed

The fundamentals of oxidative phosphorylation and photophosphorylation are revisited. New experimental data on the involvement of succinate and malate anions respectively in oxidative phosphorylation and photophosphorylation are presented. These new data offer a novel molecular mechanistic explanation for the energy coupling and ATP synthesis carried out in mitochondria and chloroplast thylakoids. The mechanism does not suffer from the flaws in Mitchell's chemiosmotic theory that have been pointed out in many studies since its first appearance 50 years ago, when it was hailed as a ground-breaking mechanistic explanation of what is perhaps the most important process in cellular energetics. The new findings fit very well with the predictions of Nath's torsional mechanism of energy transduction and ATP synthesis. It is argued that this mechanism, based on at least 15 years of experimental and theoretical work by Sunil Nath, constitutes a fundamentally different theory of the energy conversion process that eliminates all the inconsistencies in Mitchell's chemiosmotic theory pointed out by other authors. It is concluded that the energy-transducing complexes in oxidative phosphorylation and photosynthesis are proton-dicarboxylic acid anion cotransporters and not simply electrogenic proton translocators. These results necessitate revision of previous theories of biological energy transduction, coupling, and ATP synthesis. The novel molecular mechanism is extended to cover ATP synthesis in prokaryotes, in particular to alkaliphilic and haloalkaliphilic bacteria, essentially making it a complete theory addressing mechanistic, kinetic, and thermodynamic details. Finally, based on the new interpretation of oxidative phosphorylation, quantitative values for the P/O ratio, the amount of ATP generated per redox package of the reduced substrates, are calculated and compared with experimental values for fermentation on different substrates. It is our hope that the presentation of oxidative phosphorylation and photophosphorylation from a wholly new perspective will rekindle scientific discussion of a key process in bioenergetics and catalyze new avenues of research in a truly interdisciplinary field. Biotechnol. Bioeng. 2015;112: 429-437. © 2014 Wiley Periodicals, Inc. PMID:25384602

Nath, Sunil; Villadsen, John

2015-03-01

82

Neuronal substrates of Corsi Block span: Lesion symptom mapping analyses in relation to attentional competition and spatial bias.  

PubMed

Spatial working memory problems are frequently reported following brain damage within both left and right hemispheres but with the severity often being grater in individuals with right hemisphere lesions. Clinically, deficits in spatial working memory have also been noted in patients with visuospatial disorders such as unilateral neglect. Here, we examined neural substrates of short-term memory for spatial locations based on the Corsi Block tapping task and the relationship with the visuospatial deficits of neglect and extinction in a group of chronic neuropsychological patients. Principal Component Analysis (PCA) was used to distinguish shared and dissociate functional components. The neural substrates of spatial short-term memory deficits and the components identified by PCA were examined using whole brain voxel-based morphometry and tract-wise lesion deficits analyses. We found that bilateral lesions within occipital cortex (middle occipital gyrus) and right posterior parietal cortex, along with disconnection of the right parieto-temporal segment of arcuate fasciculus, were associated with low spatial memory span. A single component revealed by PCA accounted for over half of the variance and was linked to damage to right posterior brain regions (temporo-parietal junction, the inferior parietal lobule and middle temporal gyrus extending into middle occipital gyrus). We also found link to disconnections within several association pathways including the superior longitudinal fasciculus, arcuate fasciculus, inferior fronto-occipital fasciculus and inferior longitudinal fasciculus. These results indicate that different visuospatial deficits converge into a single component mapped within posterior parietal areas and fronto-parietal white matter pathways. Furthermore, the data presented here fit with the role of posterior parietal cortex/temporo-parietal junction in maintaining a map of salient locations in space, with Corsi Block performance being impaired when the spatial map is damaged. PMID:25281309

Chechlacz, Magdalena; Rotshtein, Pia; Humphreys, Glyn W

2014-10-01

83

First Grade Writers Revisit Their Work  

ERIC Educational Resources Information Center

In this article, the author focuses on first grade readers and writers who revisit their work and describes what first-graders do when they revisit their writing about science and literature and review collections of their work. The first-graders discussed here are in Elaine O'Connor's classroom at Clark Elementary School in Charlottesville. In a…

Hansen, Jane A.

2007-01-01

84

Lithium in the Pleiades Revisited  

NASA Astrophysics Data System (ADS)

New Li abundances have been derived for some 15-20 Pleiades dwarfs using new high-resolution and high S/N spectroscopy from HET/HRS. Previous studies suggested that our objects, all modest (projected) rotators, evinced considerable scatter in their Li abundances. We revisit the question of this scatter and its origin. This work has been supported by NSF grants AST 00-86576 and 02-39518, a South Carolina Space Grant Scholarship award, a generous donation from the Curry Foundation of Seneca, SC, and the NOAO Public Access Program.

King, J. R.; Hobbs, L. M.; Schuler, S. C.; Pinsonneault, M. H.

2003-12-01

85

Smith Theory Revisited William G. Dwyer  

E-print Network

Smith Theory Revisited William G. Dwyer Clarence W. Wilkerson* 1 Introduction In the late 1930's, P. A. Smith began the investigation. This thread has continued now for almost fifty years. Smith was successful in calculating the cohomology

Wilkerson, Clarence

86

Lifelong Bilingualism Contributes to Cognitive Reserve against White Matter Integrity Declines in Aging  

PubMed Central

Recent evidence suggests that lifelong bilingualism may contribute to cognitive reserve (CR) in normal aging. However, there is currently no neuroimaging evidence to suggest that lifelong bilinguals can retain normal cognitive functioning in the face of age-related neurodegeneration. Here we explored this issue by comparing white matter (WM) integrity and gray matter (GM) volumetric patterns of older adult lifelong bilinguals (N = 20) and monolinguals (N = 20). The groups were matched on a range of relevant cognitive test scores and on the established CR variables of education, socioeconomic status and intelligence. Participants underwent high-resolution structural imaging for assessment of GM volume and diffusion tensor imaging (DTI) for assessment of WM integrity. Results indicated significantly lower microstructural integrity in the bilingual group in several WM tracts. In particular, compared to their monolingual peers, the bilingual group showed lower fractional anisotropy and/or higher radial diffusivity in the inferior longitudinal fasciculus/inferior fronto-occipital fasciculus bilaterally, the fornix, and multiple portions of the corpus callosum. There were no group differences in GM volume. Our results suggest that lifelong bilingualism contributes to CR against WM integrity declines in aging. PMID:24103400

Gold, Brian T.; Johnson, Nathan F.; Powell, David K.

2013-01-01

87

Brain morphometry of Dravet syndrome.  

PubMed

The aim of this study was to identify differential global and local brain structural patterns in Dravet Syndrome (DS) patients as compared with a control subject group, using brain morphometry techniques which provide a quantitative whole-brain structural analysis that allows for specific patterns to be generalized across series of individuals. Nine patients with the diagnosis of DS that tested positive for mutation in the SCN1A gene and nine well-matched healthy controls were investigated using voxel brain morphometry (VBM), cortical thickness and cortical gyrification measurements. Global volume reductions of gray matter (GM) and white matter (WM) were related to DS. Local volume reductions corresponding to several white matter regions in brainstem, cerebellum, corpus callosum, corticospinal tracts and association fibers (left inferior fronto-occipital fasciculus and left uncinate fasciculus) were also found. Furthermore, DS showed a reduced cortical folding in the right precentral gyrus. The present findings describe DS-related brain structure abnormalities probably linked to the expression of the SCN1A mutation. PMID:25048308

Pérez, Alejandro; García-Pentón, Lorna; Canales-Rodríguez, Erick J; Lerma-Usabiaga, Garikoitz; Iturria-Medina, Yasser; Román, Francisco J; Davidson, Doug; Alemán-Gómez, Yasser; Acha, Joana; Carreiras, Manuel

2014-10-01

88

Multivariate pattern analysis of DTI reveals differential white matter in individuals with obsessive-compulsive disorder  

PubMed Central

Diffusion tensor imaging (DTI) studies have revealed group differences in white matter between patients with obsessive-compulsive disorder (OCD) and healthy controls. However, the results of these studies were based on average differences between the two groups, and therefore had limited clinical applicability. The objective of this study was to investigate whether fractional anisotropy (FA) of white matter can be used to discriminate between patients with OCD and healthy controls at the level of the individual. DTI data were acquired from 28 OCD patients and 28 demographically matched healthy controls, scanned using a 3T MRI system. Differences in FA values of white matter between OCD and healthy controls were examined using a multivariate pattern classification technique known as support vector machine (SVM). SVM applied to FA images correctly identified OCD patients with a sensitivity of 86% and a specificity of 82% resulting in a statistically significant accuracy of 84% (P ? 0.001). This discrimination was based on a distributed network including bilateral prefrontal and temporal regions, inferior fronto-occipital fasciculus, superior fronto-parietal fasciculus, splenium of corpus callosum and left middle cingulum bundle. The present study demonstrates subtle and spatially distributed white matter abnormalities in individuals with OCD, and provides preliminary support for the suggestion that that these could be used to aid the identification of individuals with OCD in clinical practice. Hum Brain Mapp 35:2643–2651, 2014. © 2013 Wiley Periodicals, Inc. PMID:24048702

Li, Fei; Huang, Xiaoqi; Tang, Wanjie; Yang, Yanchun; Li, Bin; Kemp, Graham J; Mechelli, Andrea; Gong, Qiyong

2014-01-01

89

Cognitive Processing Speed in Older Adults: Relationship with White Matter Integrity  

PubMed Central

Cognitive processing slows with age. We sought to determine the importance of white matter integrity, assessed by diffusion tensor imaging (DTI), at influencing cognitive processing speed among normal older adults, assessed using a novel battery of computerized, non-verbal, choice reaction time tasks. We studied 131 cognitively normal adults aged 55–87 using a cross-sectional design. Each participant underwent our test battery, as well as MRI with DTI. We carried out cross-subject comparisons using tract-based spatial statistics. As expected, reaction time slowed significantly with age. In diffuse areas of frontal and parietal white matter, especially the anterior corpus callosum, fractional anisotropy values correlated negatively with reaction time. The genu and body of the corpus callosum, superior longitudinal fasciculus, and inferior fronto-occipital fasciculus were among the areas most involved. This relationship was not explained by gray or white matter atrophy or by white matter lesion volume. In a statistical mediation analysis, loss of white matter integrity mediated the relationship between age and cognitive processing speed. PMID:23185621

Kerchner, Geoffrey A.; Racine, Caroline A.; Hale, Sandra; Wilheim, Reva; Laluz, Victor; Miller, Bruce L.; Kramer, Joel H.

2012-01-01

90

Neuroimaging abnormalities, neurocognitive function, and fatigue in patients with hepatitis C  

PubMed Central

Objective: This study examined neurologic abnormalities (as measured by proton magnetic resonance spectroscopy imaging and diffusion tensor imaging), neurocognitive performance, and fatigue among a sample of adults with hepatitis C virus (HCV). We hypothesized that HCV+ individuals would demonstrate structural brain abnormalities and neurocognitive compromise consistent with frontostriatal dysfunction as well as increased fatigue compared to controls. Method: Participants were 76 individuals diagnosed with HCV and 20 controls who underwent a comprehensive neurocognitive evaluation and clinical assessments. A subset of the HCV+ participants (n = 29) and all controls underwent MRI. Results: Individuals diagnosed with chronic HCV infection demonstrated greater fractional anisotropy in the striatum as well as greater mean diffusivity in the fronto-occiptal fasciculus and external capsule compared to HCV? controls. HCV+ participants also demonstrated lower levels of N-acetylaspartate in bilateral parietal white matter and elevations in myo-inosital (mI) in bilateral frontal white matter compared to HCV? controls (all p values < 0.05). HCV+ participants also demonstrated significantly poorer neuropsychological performance, particularly in processing speed and verbal fluency. HCV+ patients reported higher levels of fatigue than controls, and fatigue was significantly correlated with diffusivity in the superior fronto-occipital fasciculus, elevations in mI in frontal white matter, and overall cognitive performance. Conclusions: Our results suggest that HCV-associated neurologic complications disrupt frontostriatal structures, which may result in increased fatigue and poorer cognitive performance, particularly in those cognitive domains regulated by frontostriatal regions. PMID:25610883

Castellon, Steven A.; Singer, Elyse J.; Nagarajan, Rajakumar; Sarma, Manoj K.; Smith, Jason; Thaler, Nicholas S.; Truong, Jonathan Hien; Schonfeld, Daniel; Thomas, M. Albert; Hinkin, Charles H.

2015-01-01

91

Altered microstructure within social-cognitive brain networks during childhood in Williams syndrome.  

PubMed

Williams syndrome (WS) is a neurodevelopmental condition caused by a hemizygous deletion of ?26-28 genes on chromosome 7q11.23. WS is associated with a distinctive pattern of social cognition. Accordingly, neuroimaging studies show that WS is associated with structural alterations of key brain regions involved in social cognition during adulthood. However, very little is currently known regarding the neuroanatomical structure of social cognitive brain networks during childhood in WS. This study used diffusion tensor imaging to investigate the structural integrity of a specific set of white matter pathways (inferior fronto-occipital fasciculus [IFOF] and uncinate fasciculus [UF]) and associated brain regions [fusiform gyrus (FG), amygdala, hippocampus, medial orbitofrontal gyrus (MOG)] known to be involved in social cognition in children with WS and a typically developing (TD) control group. Children with WS exhibited higher fractional anisotropy (FA) and axial diffusivity values and lower radial diffusivity and apparent diffusion coefficient (ADC) values within the IFOF and UF, higher FA values within the FG, amygdala, and hippocampus and lower ADC values within the FG and MOG compared to controls. These findings provide evidence that the WS genetic deletion affects the development of key white matter pathways and brain regions important for social cognition. PMID:23709644

Haas, Brian W; Barnea-Goraly, Naama; Sheau, Kristen E; Yamagata, Bun; Ullas, Shruti; Reiss, Allan L

2014-10-01

92

...... Frechet Distance Revisited and Extended Sariel Har-Peled1  

E-print Network

. ...... Fr´echet Distance Revisited and Extended Sariel Har-Peled1 Benjamin Raichel1 1UIUC, Illinois, USA June 15, 2011 Har-Peled and Raichel (UIUC) Fr´echet Distance Revisited and Extended June 15 recognition, etc. Har-Peled and Raichel (UIUC) Fr´echet Distance Revisited and Extended June 15, 2011 2 / 26

Har-Peled, Sariel

93

Cholesterol and vitamins: revisited study.  

PubMed

The link between low density lipoprotein and coronary heart disease has been widely studied. Oxidized LDL damages the artery wall, and a diet rich in vitamins and low in saturated fat and cholesterol may reduce this risk. Not only hypercholesterolemia but also low levels of high density lipoprotein cholesterol are critical risk factors for atherosclerosis and related diseases. It has been reported that high doses of B complex vitamin may be useful in lowering blood cholesterol and triglyceride levels in the body, however the use of this compound has been limited by an annoying flush and concern for toxicity. Niacin is a B-complex vitamin with anti-atherosclerotic properties and is an effective medication for raising high density lipoprotein. The combination of niacin with other lipid-lowering drugs, such as statins, reduces the dynamic of atherosclerosis disease. In addition, vitamin E is one of the most important lipid soluble anti-oxidants in humans, and reduces atherosclerosis plaque, coronary artery diseases and myocardial infarction. Vitamin E protects the integrity of membranes by inhibiting lipid peroxidation. In this study we revisited the interrelationship between cholesterol, low density lipoproteins and vitamins. PMID:22217984

Saggini, A; Anogeianaki, A; Angelucci, D; Cianchetti, E; D'Alessandro, M; Maccauro, G; Salini, V; Caraffa, A; Teté, S; Conti, F; Tripodi, D; Fulcheri, M; Frydas, S; Shaik-Dasthagirisaheb, Y B

2011-01-01

94

The mycorrhiza helper bacteria revisited.  

PubMed

In natural conditions, mycorrhizal fungi are surrounded by complex microbial communities, which modulate the mycorrhizal symbiosis. Here, the focus is on the so-called mycorrhiza helper bacteria (MHB). This concept is revisited, and the distinction is made between the helper bacteria, which assist mycorrhiza formation, and those that interact positively with the functioning of the symbiosis. After considering some examples of MHB from the literature, the ecological and evolutionary implications of the relationships of MHB with mycorrhizal fungi are discussed. The question of the specificity of the MHB effect is addressed, and an assessment is made of progress in understanding the mechanisms of the MHB effect, which has been made possible through the development of genomics. Finally, clear evidence is presented suggesting that some MHB promote the functioning of the mycorrhizal symbiosis. This is illustrated for three critical functions of practical significance: nutrient mobilization from soil minerals, fixation of atmospheric nitrogen, and protection of plants against root pathogens. The review concludes with discussion of future research priorities regarding the potentially very fruitful concept of MHB. PMID:17803639

Frey-Klett, P; Garbaye, J; Tarkka, M

2007-01-01

95

Revisiting Bohr's semiclassical quantum theory.  

PubMed

Bohr's atomic theory is widely viewed as remarkable, both for its accuracy in predicting the observed optical transitions of one-electron atoms and for its failure to fully correspond with current electronic structure theory. What is not generally appreciated is that Bohr's original semiclassical conception differed significantly from the Bohr-Sommerfeld theory and offers an alternative semiclassical approximation scheme with remarkable attributes. More specifically, Bohr's original method did not impose action quantization constraints but rather obtained these as predictions by simply matching photon and classical orbital frequencies. In other words, the hydrogen atom was treated entirely classically and orbital quantized emerged directly from the Planck-Einstein photon quantization condition, E = h nu. Here, we revisit this early history of quantum theory and demonstrate the application of Bohr's original strategy to the three quintessential quantum systems: an electron in a box, an electron in a ring, and a dipolar harmonic oscillator. The usual energy-level spectra, and optical selection rules, emerge by solving an algebraic (quadratic) equation, rather than a Bohr-Sommerfeld integral (or Schroedinger) equation. However, the new predictions include a frozen (zero-kinetic-energy) state which in some (but not all) cases lies below the usual zero-point energy. In addition to raising provocative questions concerning the origin of quantum-chemical phenomena, the results may prove to be of pedagogical value in introducing students to quantum mechanics. PMID:17020371

Ben-Amotz, Dor

2006-10-12

96

Ant Foraging Revisited Liviu Alexandru Panait1  

E-print Network

Ant Foraging Revisited Liviu Alexandru Panait1 and Sean Luke1 1. Department of Computer Science: lpanait@cs.gmu.edu Abstract Previous artificial (non-biological) ant foraging models have to date relied ants with the knowledge of the nest direction. In contrast, the work presented solves ant foraging

Luke, Sean

97

The Fermat factorization method revisited Robert Erra  

E-print Network

The Fermat factorization method revisited Robert Erra Christophe Grenier 30th June 2009 Abstract We consider the well known Fermat factorization method, we call the Fermat factorization equation the equation works. 1 Introduction Fermat, in a letter to Mersenne around 1643, exposed an algorithm to factor odd

98

Patent Claims Revisited: Examiners and Trolls  

Microsoft Academic Search

In this article, the author revisits the writing of claims, and demonstrates two other styles of writing them. In one style, the author shows how to write a more narrow and focused claim. In the other style, he shows how to write claims that are beyond broad - claims that can be written prior to actually inventing anything. Note that

Philip G. Emma

2006-01-01

99

HARMONIC TWOSPHERES IN COMPACT SYMMETRIC SPACES, REVISITED  

E-print Network

HARMONIC TWO­SPHERES IN COMPACT SYMMETRIC SPACES, REVISITED F. E. Burstall and M. A. Guest Introduction The purpose of this article is to give a new description of harmonic maps from the two­sphere S 2 of such harmonic maps occur when G=K = S n or CP n . In 1967, E. Calabi gave a construction of all harmonic maps

Bath, University of

100

Biodiversity measures revisited Natalia Petrovskaya a  

E-print Network

Biodiversity measures revisited Natalia Petrovskaya a , Sergei Petrovskii b,c,*, Bai-Lian Li c, Riverside, CA 92521-0124, USA 1. Introduction Loss of biodiversity in various ecosystems all over the world to recognize the main threats for communities functioning and reasons for biodiversity loss; examples

Petrovskaya, Natalia B.

101

Common Knowledge Revisited \\Lambda Ronald Fagin  

E-print Network

that in order for something to be a convention, it must in fact be common knowledge among the members of a group #12; convention that green means ``go'' and red means ``stop'' is presumably common knowledge amongCommon Knowledge Revisited \\Lambda Ronald Fagin IBM Almaden Research Center 650 Harry Road San Jose

Vardi, Moshe Y.

102

Revisitation patterns in World Wide Web navigation  

Microsoft Academic Search

We report on users' revisitation patterns to World Wide Web pages, and use these to lay an empirical foundation for the design of history mechanisms in web browsers. Through history, a user can return quickly to a previously visited page, possibly reducing the cognitive and physical overhead required to navigate to it from scratch. We analyzed 6 weeks of usage

Linda Tauscher; Saul Greenberg

1997-01-01

103

Revisiting the Definition of Homo Sapiens  

Microsoft Academic Search

Research in genomics, human cloning, and transgenic technology has challenged bioethicists and scientists to rethink the definition of human be- ings as a species. For example, should the definition incorporate a genetic crite- rion and how does the capacity to genetically engineer human beings affect the definition of our species? In considering these contemporary bioethical dilem- mas, we revisit an

John D. Loike; Moshe David Tendler

2002-01-01

104

Internal waves revisited B.R. Sutherland  

E-print Network

Internal waves revisited B.R. Sutherland , G.O. Hughes y, S.B. Dalziel and P.F. Linden z Department and amplitude of internal waves. As well as being relatively inexpensive to set up, the technique is sensitive to small density uctuations: heat rising from a hand can easily be seen. If the internal wave eld

Sutherland, Bruce

105

The Rotating Morse-Pekeris Oscillator Revisited  

ERIC Educational Resources Information Center

The Morse-Pekeris oscillator model for the calculation of the vibration-rotation energy levels of diatomic molecules is revisited. This model is based on the realization of a second-order exponential expansion of the centrifugal term about the minimum of the vibrational Morse oscillator and the subsequent analytical resolution of the resulting…

Zuniga, Jose; Bastida, Adolfo; Requena, Alberto

2008-01-01

106

South Africa: Revisiting Capital's ‘Formative Action’  

Microsoft Academic Search

This article revisits Saul and Gelb's 1981 analysis of South African capital's ‘formative action’, employing their framework to assess how capital hasshaped the economic framework since 1990. I show that once prominentbusiness leaders became committed to non?racial democracy, the privatesector became enormously influential in shaping the economic programme.The policy changes permitted South African firms to restructure theiroperations largely on their

Carolyn Bassett

2008-01-01

107

Empirically Revisiting the Test Independence Assumption  

E-print Network

Empirically Revisiting the Test Independence Assumption Sai Zhang, Darioush Jalali, Jochen Wuttke}@cs.washington.edu ABSTRACT In a test suite, all the test cases should be independent: no test should affect any other test's result, and running the tests in any order should produce the same test results. Techniques such as test

Ernst, Michael

108

Women's Place, Revisited (NYT) 421 words  

E-print Network

Women's Place, Revisited (NYT) 421 words Published: January 19, 2006 The election on Sunday of Michelle Bachelet as Chile's president completes a three- continent long jump for women in politics. Ms strongman. On Monday, when Ellen Johnson Sirleaf was inaugurated as president of Liberia, she became Africa

Lopez-Carr, David

109

Security of Invertible Media Authentication Schemes Revisited  

Microsoft Academic Search

Dittmann, Katzenbeisser, Schallhart and Veith (IACR ePrint 2004) intro- duced the notion of invertible media authentication schemes, embedding authentication data in media objects via invertible watermarks. These invertible watermarks allow to recover the original media object (given a secret encryption key), as required for example in some medical applications where the distortion must be removable. Here we revisit the approach

Daniel Dönigus; Stefan Endler; Marc Fischlin; Andreas Hülsing; Patrick Jäger; Anja Lehmann; Sergey Podrazhansky; Sebastian Schipp; Erik Tews; Sven Vowe; Matthias Walthart; Frederik Weidemann

2007-01-01

110

ORIGINAL ARTICLE Cytosolic potassium homeostasis revisited: 42  

E-print Network

ORIGINAL ARTICLE Cytosolic potassium homeostasis revisited: 42 K-tracer analysis in Hordeum vulgare of the flexibility, rather than strict homeostasis, of cellular K+ maintenance, and of the dynamic interaction analysis Ã? 42 K Ã? Hordeum Ion transport Ã? Homeostasis Introduction Potassium (K+ ) availability in both

Britto, Dev T.

111

Navjot's nightmare revisited: logging, agriculture, and biodiversity  

E-print Network

tremendous biodiversity loss. This loss is exac- erbated by increased fire frequency. Therefore, we conNavjot's nightmare revisited: logging, agriculture, and biodiversity in Southeast Asia David S Raffles Museum of Biodiversity Research, National University of Singapore, 117546, Singapore 3 Centre

Vermont, University of

112

Revisiting Fascist Italy's Crime in Ethiopia ? I???? ???  

Microsoft Academic Search

This essay will make a brief historical synopsis and analysis of the crimes perpetrated by the Italian fascists against the Ethiopian people in the 1930s. At this particular juncture, it may sound ironic to revisit the crimes against humanity committed in Ethiopia by Fascist henchmen like Marshall Pietro Badoglio and Marshal Rodolfo Graziani, but sometimes the past contends with the

Ghelawdewos Araia

113

Smith Theory Revisited William G. Dwyer  

E-print Network

Smith Theory Revisited William G. Dwyer Clarence W. Wilkerson \\Lambda 1 Introduction In the late 1930's, P. A. Smith began the investigation of the cohomological properties of a group G of prime order fifty years. Smith was successful in calculating the cohomology of the the fixed point sets

Wilkerson, Clarence

114

Smith Theory Revisited William G. Dwyer  

E-print Network

Smith Theory Revisited William G. Dwyer Clarence W. Wilkerson 1 Introduction In the late 1930's, P. A. Smith began the investigation of the cohomological properties of a group G of prime order p. Smith was successful in calculating the cohomology of the the fixed point sets for involutions

Wilkerson, Clarence

115

DWORKIN'S ARGUMENT REVISITED: POINT PROCESSES, DYNAMICS, DIFFRACTION,  

E-print Network

********************************************** DWORKIN'S ARGUMENT REVISITED: POINT PROCESSES, DYNAMICS, DIFFRACTION, AND CORRELATIONS XINGHUA DENG sets by the vectors of Rd . Steven Dworkin's argument relates the diffraction of the typical point sets space of Rd under the diffraction measure into L2 (X, µ). We examine the image of this embedding

Moody, Robert Vaughan

116

Revisiting the Skills Agenda: A Complicated Geography  

ERIC Educational Resources Information Center

This paper revisits the skills agenda and suggests that in light of shifts from supply-side to demand-led provision within the UK higher education sector, there is a need to think more critically about the role and place of skills within university curricula. It suggests that if universities are to respond effectively to sector changes, then the…

Saunders, Angharad

2011-01-01

117

Multi-modal MRI of mild traumatic brain injury  

PubMed Central

Multi-modal magnetic resonance imaging (MRI) that included high resolution structural imaging, diffusion tensor imaging (DTI), magnetization transfer ratio (MTR) imaging, and magnetic resonance spectroscopic imaging (MRSI) were performed in mild traumatic brain injury (mTBI) patients with negative computed tomographic scans and in an orthopedic-injured (OI) group without concomitant injury to the brain. The OI group served as a comparison group for mTBI. MRI scans were performed both in the acute phase of injury (~24 h) and at follow-up (~90 days). DTI data was analyzed using tract based spatial statistics (TBSS). Global and regional atrophies were calculated using tensor-based morphometry (TBM). MTR values were calculated using the standard method. MRSI was analyzed using LC Model. At the initial scan, the mean diffusivity (MD) was significantly higher in the mTBI cohort relative to the comparison group in several white matter (WM) regions that included internal capsule, external capsule, superior corona radiata, anterior corona radiata, posterior corona radiata, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, forceps major and forceps minor of the corpus callosum, superior longitudinal fasciculus, and corticospinal tract in the right hemisphere. TBSS analysis failed to detect significant differences in any DTI measures between the initial and follow-up scans either in the mTBI or OI group. No significant differences were found in MRSI, MTR or morphometry between the mTBI and OI cohorts either at the initial or follow-up scans with or without family wise error (FWE) correction. Our study suggests that a number of WM tracts are affected in mTBI in the acute phase of injury and that these changes disappear by 90 days. This study also suggests that none of the MRI-modalities used in this study, with the exception of DTI, is sensitive in detecting changes in the acute phase of mTBI. PMID:25610770

Narayana, Ponnada A.; Yu, Xintian; Hasan, Khader M.; Wilde, Elisabeth A.; Levin, Harvey S.; Hunter, Jill V.; Miller, Emmy R.; Patel, Vipul Kumar S.; Robertson, Claudia S.; McCarthy, James J.

2014-01-01

118

Multi-modal MRI of mild traumatic brain injury.  

PubMed

Multi-modal magnetic resonance imaging (MRI) that included high resolution structural imaging, diffusion tensor imaging (DTI), magnetization transfer ratio (MTR) imaging, and magnetic resonance spectroscopic imaging (MRSI) were performed in mild traumatic brain injury (mTBI) patients with negative computed tomographic scans and in an orthopedic-injured (OI) group without concomitant injury to the brain. The OI group served as a comparison group for mTBI. MRI scans were performed both in the acute phase of injury (~24 h) and at follow-up (~90 days). DTI data was analyzed using tract based spatial statistics (TBSS). Global and regional atrophies were calculated using tensor-based morphometry (TBM). MTR values were calculated using the standard method. MRSI was analyzed using LC Model. At the initial scan, the mean diffusivity (MD) was significantly higher in the mTBI cohort relative to the comparison group in several white matter (WM) regions that included internal capsule, external capsule, superior corona radiata, anterior corona radiata, posterior corona radiata, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, forceps major and forceps minor of the corpus callosum, superior longitudinal fasciculus, and corticospinal tract in the right hemisphere. TBSS analysis failed to detect significant differences in any DTI measures between the initial and follow-up scans either in the mTBI or OI group. No significant differences were found in MRSI, MTR or morphometry between the mTBI and OI cohorts either at the initial or follow-up scans with or without family wise error (FWE) correction. Our study suggests that a number of WM tracts are affected in mTBI in the acute phase of injury and that these changes disappear by 90 days. This study also suggests that none of the MRI-modalities used in this study, with the exception of DTI, is sensitive in detecting changes in the acute phase of mTBI. PMID:25610770

Narayana, Ponnada A; Yu, Xintian; Hasan, Khader M; Wilde, Elisabeth A; Levin, Harvey S; Hunter, Jill V; Miller, Emmy R; Patel, Vipul Kumar S; Robertson, Claudia S; McCarthy, James J

2015-01-01

119

Pearson's meta-analysis 1 Pearson's meta-analysis revisited  

E-print Network

leads to something new that may be better revisited #12;Pearson's meta-analysis 3 Karl Pearson quote Stigler (2008) recounting Karl Pearson's amazing productivity includes this from Stouffer (1958): "YouPearson's meta-analysis 1 Pearson's meta-analysis revisited in a microarray context Art B. Owen

Owen, Art

120

Karl Pearson's meta-analysis revisited Art B. Owen  

E-print Network

Karl Pearson's meta-analysis revisited Art B. Owen Department of Statistics Sequoia Hall 390 Serra: This paper revisits a meta-analysis method proposed by Pearson (1934) and first used by David (1933 that the method Birnbaum analyzed is not the one that Pearson proposed. We show that Pearson's proposal

Owen, Art

121

Global angiosperm family richness revisited: linking ecology and evolution  

E-print Network

ORIGINAL ARTICLE Global angiosperm family richness revisited: linking ecology and evolution The global richness gradient of angiosperm families is correlated with current climate, and it has been the pattern. We revisit this issue using the Angiosperm Phylogeny Group (APG) III classification and revised

Rodríguez, Miguel Ángel

122

Extended Temporal Logic Revisited Orna Kupferman  

E-print Network

Extended Temporal Logic Revisited Orna Kupferman ¢¡ Nir Piterman £ Moshe Y. Vardi ¤¥¡¦¡ § Hebrew Rice University, Department of Computer Science, Houston, TX 77251-1892, U.S.A. Email: vardi@cs.rice.edu, URL: http://www.cs.rice.edu/ ¨ vardi Abstract. A key issue in the design of a model-checking tool

Kupferman, Orna

123

THE MATHEMATICAL FOUNDATIONS OF GAUGE THEORY REVISITED  

E-print Network

@cermics.enpc.fr ABSTRACT We start recalling with critical eyes the mathematical methods used in gauge theory and prove also [4,6,7,30]). The pupose of this introduction is to revisit these foundations with critical eyes of G if 1 hal-00874139,version1-17Oct2013 #12;aS S, a G and the orbit of x X is the invariant subset

Paris-Sud XI, Université de

124

Karl Pearson's meta-analysis revisited  

Microsoft Academic Search

This paper revisits a meta-analysis method proposed by Pearson [Biometrika 26 (1934) 425--442] and first used by David [Biometrika 26 (1934) 1--11]. It was thought to be inadmissible for over fifty years, dating back to a paper of Birnbaum [J. Amer. Statist. Assoc. 49 (1954) 559--574]. It turns out that the method Birnbaum analyzed is not the one that Pearson

Art B. Owen

2009-01-01

125

Association between white matter fiber structure and reward-related reactivity of the ventral striatum.  

PubMed

Individual responsiveness to rewards or rewarding stimuli may affect various domains of normal as well as pathological behavior. The ventral striatum/nucleus accumbens (NAcc) constitutes a key brain structure in the regulation of reward-appetitive behavior. It remains unclear, however, to which extent individual reward-related BOLD response in the NAcc is dependent on individual characteristics of connecting white matter fiber tracts. Using tract-based spatial statistics (TBSS) and statistical parametric mapping (SPM) this combined DTI - fMRI study investigated this question by correlating NAcc BOLD signal upon receipt of a monetary reward with different white matter characteristics (FA, axial diffusivity, radial diffusivity). The results show that increased integrity of white matter as assessed by FA in the cingulate and corpus callosum, the inferior fronto-occipital fasciculus, the anterior thalamic radiation and the anterior limb of the internal capsule was positively correlated with reward-related activation in the NAcc. There were no negative correlations as well as no significant results regarding axial and radial diffusivity. These findings indicate that microstructural properties of fiber tracts connecting, amongst others, the cortex with the striatum may influence intensity of reward-related responsiveness of the ventral striatum by constraining or increasing efficiency in information transfer within relevant circuitries involved in processing of reward. PMID:23616433

Koch, Kathrin; Wagner, Gerd; Schachtzabel, Claudia; Schultz, C Christoph; Güllmar, Daniel; Reichenbach, Jürgen R; Sauer, Heinrich; Zimmer, Claus; Schlösser, Ralf G M

2014-04-01

126

Pathways to Seeing Music: Enhanced Structural Connectivity in Colored-Music Synesthesia  

PubMed Central

Synesthesia, a condition in which a stimulus in one sensory modality consistently and automatically triggers concurrent percepts in another modality, provides a window into the neural correlates of cross-modal associations. While research on grapheme-color synesthesia has provided evidence for both hyperconnectivity/hyperbinding and disinhibited feedback as possible underlying mechanisms, less research has explored the neuroanatomical basis of other forms of synesthesia. In the current study we investigated the white matter correlates of colored-music synesthesia. As these synesthetes report seeing colors upon hearing musical sounds, we hypothesized they might show different patterns of connectivity between visual and auditory association areas. We used diffusion tensor imaging to trace the white matter tracts in temporal and occipital lobe regions in 10 synesthetes and 10 matched non-synesthete controls. Results showed that synesthetes possessed different hemispheric patterns of fractional anisotropy, an index of white matter integrity, in the inferior fronto-occipital fasciculus (IFOF), a major white matter pathway that connects visual and auditory association areas to frontal regions. Specifically, white matter integrity within the right IFOF was significantly greater in synesthetes than controls. Furthermore, white matter integrity in synesthetes was correlated with scores on audiovisual tests of the Synesthesia Battery, especially in white matter underlying the right fusiform gyrus. Our findings provide the first evidence of a white matter substrate of colored-music synesthesia, and suggest that enhanced white matter connectivity is involved in enhanced cross-modal associations. PMID:23454047

Zamm, Anna; Schlaug, Gottfried; Eagleman, David M.; Loui, Psyche

2013-01-01

127

Pathways to seeing music: enhanced structural connectivity in colored-music synesthesia.  

PubMed

Synesthesia, a condition in which a stimulus in one sensory modality consistently and automatically triggers concurrent percepts in another modality, provides a window into the neural correlates of cross-modal associations. While research on grapheme-color synesthesia has provided evidence for both hyperconnectivity-hyperbinding and disinhibited feedback as potential underlying mechanisms, less research has explored the neuroanatomical basis of other forms of synesthesia. In the current study we investigated the white matter correlates of colored-music synesthesia. As these synesthetes report seeing colors upon hearing musical sounds, we hypothesized that they might show unique patterns of connectivity between visual and auditory association areas. We used diffusion tensor imaging to trace the white matter tracts in temporal and occipital lobe regions in 10 synesthetes and 10 matched non-synesthete controls. Results showed that synesthetes possessed hemispheric patterns of fractional anisotropy, an index of white matter integrity, in the inferior fronto-occipital fasciculus (IFOF), a major white matter pathway that connects visual and auditory association areas to frontal regions. Specifically, white matter integrity within the right IFOF was significantly greater in synesthetes than controls. Furthermore, white matter integrity in synesthetes was correlated with scores on audiovisual tests of the Synesthesia Battery, especially in white matter underlying the right fusiform gyrus. Our findings provide the first evidence of a white matter substrate of colored-music synesthesia, and suggest that enhanced white matter connectivity is involved in enhanced cross-modal associations. PMID:23454047

Zamm, Anna; Schlaug, Gottfried; Eagleman, David M; Loui, Psyche

2013-07-01

128

Proper Motion of the Crab Pulsar Revisited  

E-print Network

It has been suggested that the Crab pulsar's proper motion is well aligned with the symmetry axis of the pulsar wind nebula. We have re-visited this question, examining over 6 years of F547M WFPC2 chip 3 images to obtain a best-fit value of $\\mu_\\ast = 14.9 \\pm 0.8$mas/yr at PA $278\\arcdeg \\pm 3\\arcdeg$. At $26\\arcdeg\\pm 3\\arcdeg$ to the nebula axis, this substantially relaxes constraints on the birth kick of this pulsar. Such misalignment allows the momentum to be imparted over $\\sim$1s timescales.

C. -Y. Ng; Roger W. Romani

2006-02-11

129

Revisiting Gribov's copies inside the horizon  

NASA Astrophysics Data System (ADS)

In this work, we revisit the problem of legitimate topologically trivial Gribov copies inside the Gribov horizon. We avoid the reducibility problem which hampered the standard construction of van Baal, and then we are able to build a valid example with spherical symmetry. We also apply the same technique in the presence of a background of a Polyakov instanton in a Euclidian 3D spacetime, in order to study the effect of a non-trivial environment in the generation of multiple copies inside the horizon.

Landim, R. R.; Lemes, V. E. R.; Ventura, O. S.; Vilar, L. C. Q.

2014-11-01

130

Sloan Digital Sky Survey Photometric Calibration Revisited  

SciTech Connect

The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.

Marriner, John; /Fermilab

2012-06-29

131

Orthorhombic Zr2Co11 phase revisited  

SciTech Connect

The structure of the orthorhombic Zr2Co11 phase was revisited in the present work. Selected-area electron diffraction (SAED) and high-resolution electron microscopy (HREM) techniques were used to investigate the structure. They show the orthorhombic Zr2Co11 phase has a 1-D incommensurate modulated structure. The structure can be approximately described as a B-centered orthorhombic lattice. The lattice parameters of the orthorhombic Zr2Co11 phase have been determined by a tilt series of SAED patterns. A hexagonal network with a modulation wave has been observed in the HREM image and the hexagonal motif is considered as the basic structural unit.

Li, X. -Z. [University of Nebraska; Zhang, W. Y. [University of Nebraska; Sellmyer, D. J. [University of Nebraska; Zhao, X. [Ames Laboratory; Nguyen, M. C. [Ames Laboratory; Wang, C. Z. [Ames Laboratory; Ho, K. M. [Ames Laboratory

2014-10-01

132

Expressiveness Revisited Carlos Areces and Maarten de Rijke  

E-print Network

Expressiveness Revisited Carlos Areces and Maarten de Rijke ILLC, University of Amsterdam Plantage de­ scription logic was really a logic in the strict sense of the notion (i.e., with a formal syntax

Amsterdam, University of

133

Zebra Finch Sexual Differentiation: The Aromatization Hypothesis Revisited  

E-print Network

Zebra Finch Sexual Differentiation: The Aromatization Hypothesis Revisited JULI WADE Departments; testosterone; sexual dimorphism ABSTRACT Zebra finches have emerged as an outstanding model system organ. Other dimorphic aspects of reproduction in the zebra finch, such as copulatory behaviors

Wade, Juli

134

Distance Perception in Immersive Virtual Environments, Revisited Victoria Interrante  

E-print Network

Distance Perception in Immersive Virtual Environments, Revisited Victoria Interrante 1 , Lee experiments in which we assess egocentric distance perception in a high fidelity, low latency, immersive perception appears not to be significantly compressed in the immersive virtual environment, relative

Interrante, Victoria

135

A Revisiting of Scientific and Philosophical Perspectives on  

E-print Network

by James Clerk Maxwell is generally acknowledged as one of the most innovative concepts ever introducedA Revisiting of Scientific and Philosophical Perspectives on Maxwell's Displacement Current; Maxwell equations; Maxwell; scientific approach 1. Introduction Maxwell's electromagnetic theory is one

Broschat, Shira Lynn

136

``Interval Rational = Algebraic'' Revisited: A More Computer Realistic Result  

E-print Network

the numbers representable in a computer are rational and therefore, form a set of Lebesgue measure 0, only rational numbers ``Interval Rational = Algebraic'' Revisited: A More Computer Realistic Result Anatoly V. Lakeyev 1

Kreinovich, Vladik

137

Herpetologists' League The Polytypic Species Revisited: Morphological Differentiation among Tiger Salamanders  

E-print Network

Herpetologists' League The Polytypic Species Revisited: Morphological Differentiation among Tiger REVISITED: MORPHOLOGICAL DIFFERENTIATION AMONG TIGER SALAMANDERS (AMBYSTOMA TIGRINUM) (AMPHIBIA: CAUDATA Ambystoma tigrinum and two closely related members of the tiger salamander complex, A. californiense and A

Shaffer, H. Bradley

138

Resonance on the web: web dynamics and revisitation patterns  

Microsoft Academic Search

The Web is a dynamic, ever-changing collection of information accessed in a dynamic way. This paper explores the relationship between Web page content change (obtained from an hourly crawl of over 40K pages) and people's revisitation to those pages (collected via a large scale log analysis of 2.3M users). We identify the relationship, or resonance, between revisitation behavior and the

Eytan Adar; Jaime Teevan; Susan T. Dumais

2009-01-01

139

Waugh revisited : destabilizing language and structure in Vile bodies, A handful of dust, and Brideshead revisited by Jabe Ziino.  

E-print Network

Introduction: Last Fall semester I had only a very vague idea of a thesis topic: with a broad interest in the conflict between romantic love and religion inspired in part by a summertime reading of Brideshead Revisited, I ...

Ziino, Jabe (Jabe S.)

2011-01-01

140

Effects of early-life adversity on white matter diffusivity changes in patients at risk for major depression  

PubMed Central

Background Relatives of patients with major depressive disorder (MDD) and people who experienced early-life adversity are at risk for MDD. The aim of our study was to investigate whether unaffected first-degree healthy relatives (UHRs) of patients with MDD show changes in white matter fibre connections compared with healthy controls and whether there are interactions between early-life adversity and these microstructural changes. Methods Unaffected, healthy first-degree relatives of patients with MDD and healthy controls without any family history for a psychiatric disease underwent high angular resolution diffusion imaging with 61 diffusion directions. Data were analyzed with tract-based spatial statistics, and findings were confirmed with tractography. Results Twenty-one UHRs and 24 controls participated in our study. The UHRs showed greater fractional anisotropy than controls in the body and splenium of the corpus callosum, inferior fronto-occipital fasciculus (IFO), left superior longitudinal fasciculus (SLF) and right fornix. The UHRs who experienced more early-life adversity had greater fractional anisotropy than those with less early-life adversity in the splenium of the corpus callosum, fornix, IFO and SLF; in controls, early-life adversity was found to be associated with decreased fractional anisotropy in these fibre tracts. Limitations Studying participants’ strategies for coping with early-life adversity would have been helpful. Crossing fibres in tracts are a general limitation of the method used. Conclusion Altogether, our findings provide evidence for greater fractional anisotropy in UHRs and for interaction between early-life adversity and family risk on white matter tracts involved in cognitive–emotional processes. Whether stronger neural fibre connections are associated with more resilience against depression needs to be addressed in future studies. PMID:22008179

Frodl, Thomas; Carballedo, Angela; Fagan, Andrew J.; Lisiecka, Danuta; Ferguson, Yolande; Meaney, James F.

2012-01-01

141

Perturbative Deformations of Conformal Field Theories Revisited  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to revisit the theory of perturbative deformations of conformal field theory from a mathematically rigorous, purely worldsheet point of view. We specifically include the case of N = (2,2) conformal field theories. From this point of view, we find certain surprising obstructions, which appear to indicate that contrary to previous findings, not all deformations along marginal fields exist perturbatively. This includes the case of deformation of the Gepner model of the Fermat quintic along certain cc fields. In other cases, including Gepner models of K3-surfaces and the free field theory, our results coincides with known predictions. We give partial interpretation of our results via renormalization and mirror symmetry.

Kriz, Igor

142

Trace anomalies in chiral theories revisited  

NASA Astrophysics Data System (ADS)

Motivated by the search for possible CP violating terms in the trace of the energy-momentum tensor in theories coupled to gravity we revisit the problem of trace anomalies in chiral theories. We recalculate the latter and ascertain that in the trace of the energy-momentum tensor of theories with chiral fermions at one-loop the Pontryagin density appears with an imaginary coefficient. We argue that this may break unitarity, in which case the trace anomaly has to be used as a selective criterion for theories, analogous to the chiral anomalies in gauge theories. We analyze some remarkable consequences of this fact, that seem to have been overlooked in the literature.

Bonora, Loriano; Giaccari, Stefano; de Souza, Bruno Lima

2014-07-01

143

Nonlinear Dynamics of Mirror Instability Revisited  

SciTech Connect

A nonlinear dynamics of the mirror modes near the instability threshold is revisited. It is shown that the major saturation is provided by modification of the velocity distribution function in the vicinity of small parallel ion velocities. The final relaxation scenario is based on almost resonant particle interaction with mirror modes. The saturated plasma state can be considered as a magnetic counterpart to electrostatic Bernstein-Greene-Kruskal modes. Our analytical model is verified by relevant numerical simulations. Test particle and PIC simulations indeed show that it is a modification of distribution function at small parallel velocities that results in fading away of free energy driving mirror mode. The physical similarity of the mirror and Weibel instabilities is demonstrated. The multipoint satellite measurements in space plasma can be used to validate a proposed scenario.

Pokhotelov, O. A.; Balikhin, M. A. [Automatic Control Systems Engineering, University of Sheffield, Sheffield (United Kingdom); Sagdeev, R. Z.; Dudnikova, G. I. [Department of Physics, University of Maryland, College Park, Maryland (United States); Fedun, V. N. [Department of Applied Mathematics, University of Sheffield, Sheffield (United Kingdom)

2010-12-14

144

The Doppler spread theory and parameterization revisited  

NASA Astrophysics Data System (ADS)

The author's earlier Doppler Spread Theory (DST) and Doppler Spread Parameterization (DSP) are revisited with a new understanding of the dichotomous roles played by nonlinearity in Eulerian and Lagrangian coordinates, respectively. An embryo Lagrangian DST is introduced and employed to assess the original DST. Earlier results near the Eulerian spectral peak are found to be reasonably valid, whereas those at greater vertical wavenumber are confirmed to have produced too much spreading. The earlier DSP is found to need little if any change, though specific values are suggested for its two most important ``fudge factors''. In a more general context, the continuing identity of a wave undergoing certain nonlinear interactions with other waves is discussed.

Hines, Colin O.

2004-07-01

145

Revisiting Twomey's approximation for peak supersaturation  

NASA Astrophysics Data System (ADS)

Twomey's seminal 1959 paper provided lower and upper bound approximations to the estimation of peak supersaturation within an updraft and thus provides the first closed expression for the number of nucleated cloud droplets. The form of this approximation is simple, but provides a surprisingly good estimate and has subsequently been employed in more sophisticated treatments of nucleation parametrization. In the current paper, we revisit the lower bound approximation of Twomey and make a small adjustment which can be used to obtain a more accurate calculation of peak supersaturation under all potential aerosol loadings and thermodynamic conditions. In order to make full use of this improved approximation, the underlying integro-differential equation for supersaturation evolution and the condition for calculating peak supersaturation are examined. A simple rearrangement of the algebra allows for an expression to be written down which can then be solved with a single lookup table with only one independent variable for an underlying lognormal aerosol population. Multimode aerosol with only N different dispersion characteristics require only N of these one-dimensional lookup tables. No additional information is required in the lookup table to deal with additional chemical, physical or thermodynamic properties. The resulting implementation provides a relatively simple, yet computationally cheap and very accurate physically-based parametrization of droplet nucleation for use in climate and NWP models.

Shipway, B. J.

2014-10-01

146

Carbon emission from global hydroelectric reservoirs revisited.  

PubMed

Substantial greenhouse gas (GHG) emissions from hydropower reservoirs have been of great concerns recently, yet the significant carbon emitters of drawdown area and reservoir downstream (including spillways and turbines as well as river reaches below dams) have not been included in global carbon budget. Here, we revisit GHG emission from hydropower reservoirs by considering reservoir surface area, drawdown zone and reservoir downstream. Our estimates demonstrate around 301.3 Tg carbon dioxide (CO2)/year and 18.7 Tg methane (CH4)/year from global hydroelectric reservoirs, which are much higher than recent observations. The sum of drawdown and downstream emission, which is generally overlooked, represents 42 % CO2 and 67 % CH4 of the total emissions from hydropower reservoirs. Accordingly, the global average emissions from hydropower are estimated to be 92 g CO2/kWh and 5.7 g CH4/kWh. Nonetheless, global hydroelectricity could currently reduce approximate 2,351 Tg CO2eq/year with respect to fuel fossil plant alternative. The new findings show a substantial revision of carbon emission from the global hydropower reservoirs. PMID:24943886

Li, Siyue; Zhang, Quanfa

2014-12-01

147

Revisiting the phase diagram of hard ellipsoids.  

PubMed

In this work, the well-known Frenkel-Mulder phase diagram of hard ellipsoids of revolution [D. Frenkel and B. M. Mulder, Mol. Phys. 55, 1171 (1985)] is revisited by means of replica exchange Monte Carlo simulations. The method provides good sampling of dense systems and so, solid phases can be accessed without the need of imposing a given structure. At high densities, we found plastic solids and fcc-like crystals for semi-spherical ellipsoids (prolates and oblates), and SM2 structures [P. Pfleiderer and T. Schilling, Phys. Rev. E 75, 020402 (2007)] for x : 1-prolates and 1 : x-oblates with x ? 3. The revised fluid-crystal and isotropic-nematic transitions reasonably agree with those presented in the Frenkel-Mulder diagram. An interesting result is that, for small system sizes (100 particles), we obtained 2:1- and 1.5:1-prolate equations of state without transitions, while some order is developed at large densities. Furthermore, the symmetric oblate cases are also reluctant to form ordered phases. PMID:22482570

Odriozola, Gerardo

2012-04-01

148

Critical boundary sine-Gordon revisited  

SciTech Connect

We revisit the exact solution of the two space-time dimensional quantum field theory of a free massless boson with a periodic boundary interaction and self-dual period. We analyze the model by using a mapping to free fermions with a boundary mass term originally suggested in Ref. [J. Polchinski, L. Thorlacius, Phys. Rev. D 50 (1994) 622]. We find that the entire SL (2, C) family of boundary states of a single boson are boundary sine-Gordon states and we derive a simple explicit expression for the boundary state in fermion variables and as a function of sine-Gordon coupling constants. We use this expression to compute the partition function. We observe that the solution of the model has a strong-weak coupling generalization of T-duality. We then examine a class of recently discovered conformal boundary states for compact bosons with radii which are rational numbers times the self-dual radius. These have simple expression in fermion variables. We postulate sine-Gordon-like field theories with discrete gauge symmetries for which they are the appropriate boundary states.

Hasselfield, M. [Pacific Institute for Theoretical Physics, Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada); Lee, Taejin [Pacific Institute for Theoretical Physics, Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada); Department of Physics, Kangwon University, Chuncheon 200-701 (Korea, Republic of); Asia Pacific Center for Theoretical Physics, Pohang 790-784 (Korea, Republic of); Semenoff, G.W. [Pacific Institute for Theoretical Physics, Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada) and Institute des Hautes Etudes Scientifiques, Le Bois-Marie 35, F-91440 Bures-sur-Yvette (France)]. E-mail: gordonws@phas.ubc.ca; Stamp, P.C.E. [Pacific Institute for Theoretical Physics, Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC, V6T 1Z1 (Canada)

2006-12-15

149

Pair Production Constraints on Superluminal Neutrinos Revisited  

SciTech Connect

We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p{sup 2} can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.

Brodsky, Stanley J.; /SLAC; Gardner, Susan; /Kentucky U.

2012-02-16

150

CRISPR revisited: structure prediction of CRISPR repeats Sita Lange1  

E-print Network

CRISPR revisited: structure prediction of CRISPR repeats Sita Lange1 , Omer S. Alkhnbashi 1 Regularly Interspaced Short Palindromic Repeats (CRISPRs), illustrated to the right. The CRISPR transcripts sequences have been found to match foreign virus or plasmid DNA. A set of CRISPR-associated (Cas) proteins

Will, Sebastian

151

Ant Foraging Revisited Liviu A. Panait and Sean Luke  

E-print Network

Ant Foraging Revisited Liviu A. Panait and Sean Luke George Mason University, Fairfax, VA 22030 lpanait@cs.gmu.edu, sean@cs.gmu.edu Abstract Most previous artificial ant foraging algorithms have to date the artificial ants with the knowledge of the nest direction. In contrast, the work presented solves ant foraging

Turk, Greg

152

Ant Foraging Revisited Liviu A. Panait and Sean Luke  

E-print Network

Ant Foraging Revisited Liviu A. Panait and Sean Luke George Mason University, Fairfax, VA 22030 lpanait@cs.gmu.edu, sean@cs.gmu.edu Abstract Most previous artificial ant foraging models have to date re the artificial ants with the knowledge of the nest direction. In contrast, the work presented solves ant foraging

George Mason University

153

Friction versus dilation revisited: Insights from theoretical and numerical models  

E-print Network

Friction versus dilation revisited: Insights from theoretical and numerical models N. Makedonska,1 controlled by the frictional strength of the fault gouge, a granular layer that accumulates between the fault friction coefficient) of such granular layers is the systems resistance to dilation, a byprocess

Einat, Aharonov

154

Revisiting Evolutionary Game Theory Ilaria Brunetti and Eitan Altman  

E-print Network

Revisiting Evolutionary Game Theory Ilaria Brunetti and Eitan Altman Abstract-- Evolutionary game such as the linguistics, economics and engineering. The current theory of evolutionary game makes an implicit assumption class of such individuals. I. INTRODUCTION Evolutionary game theory (EGT) started as a theory

Paris-Sud XI, Université de

155

Ostwald Ripening: The screening length revisited Barbara Niethammer Felix Otto  

E-print Network

Ostwald Ripening: The screening length revisited Barbara Niethammer Felix Otto Institut f, a phenomenon called Ostwald ripening. Lifshitz, Slyozov and Wagner formally derived an evolution Introduction 1.1 The Cahn{Hilliard model Ostwald ripening may for instance occur in phase segregation of a two

Otto, Felix

156

The Fermat factorization method revisited Robert Erra # Christophe Grenier +  

E-print Network

The Fermat factorization method revisited Robert Erra # Christophe Grenier + 30th June 2009 Abstract We consider the well known Fermat factorization method, we call the Fermat factorization equation with proposals for future works. 1 Introduction Fermat, in a letter to Mersenne around 1643, exposed an algorithm

157

Facilitating Grade Acceleration: Revisiting the Wisdom of John Feldhusen  

ERIC Educational Resources Information Center

This article revisits the 1986 Feldhusen, Proctor, and Black recommendations on grade skipping. These recommendations originally appeared as 12 guidelines. In this article, the guidelines are grouped into three general categories: how to screen accelerant candidates, how to engage with the adults in the acceleration process (e.g., teachers,…

Culross, Rita R.; Jolly, Jennifer L.; Winkler, Daniel

2013-01-01

158

Gale-Shapley Stable Marriage Problem Revisited: Strategic Issues  

E-print Network

Gale-Shapley Stable Marriage Problem Revisited: Strategic Issues and Applications Chung-Piaw Teo@nus.edu.sg · jay@ieor.columbia.edu We study strategic issues in the Gale-Shapley stable marriage model behavior of the students need not be a major concern. (Stable Marriage; Strategic Issues; Gale

Sethuraman, Jay

159

Rural-Nonrural Disparities in Postsecondary Educational Attainment Revisited  

ERIC Educational Resources Information Center

Using data from the National Educational Longitudinal Study, this study revisited rural-nonrural disparities in educational attainment by considering a comprehensive set of factors that constrain and support youth's college enrollment and degree completion. Results showed that rural students were more advantaged in community social resources…

Byun, Soo-yong; Meece, Judith L.; Irvin, Matthew J.

2012-01-01

160

REVISITING MALARIA: MOVING FROM CONTROL TO SUSTAINABLE ELIMINATION  

E-print Network

REVISITING MALARIA: MOVING FROM CONTROL TO SUSTAINABLE ELIMINATION December 8-12, 2013 Hebrew, Malaria and Professor Israel Kligler" (Room 436) 20:30-21:00 Discuss Conference agenda, format;9:30 ­ 13:15 HISTORICAL MODELS OF MALARIA ERADICATION Moderator: Prof. Nadav Davidovitch, Chair, Center

Yehoshua, Kolodny

161

Stuck Schools Revisited: Beneath the Averages. K-12 Policy  

ERIC Educational Resources Information Center

"Stuck Schools Revisited: Beneath the Averages" shows why a national focus on turning around the lowest performing schools, while needed, is not enough to raise achievement and close gaps. The report analyzes student achievement data from Maryland and Indiana, which reflect the outcomes seen in other states. The results confirm a troubling…

Ushomirsky, Natasha

2011-01-01

162

The angular momentum of baryons and dark matter halos revisited  

Microsoft Academic Search

Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive mesh refinement, we find that at the time of accretion, gas and dark matter do carry a similar amount of specific

Taysun Kimm; Julien Devriendt; Adrianne Slyz; Christophe Pichon; Susan A. Kassin; Yohan Dubois

2011-01-01

163

Nurse Rostering and Integer Programming Revisited John Thornton  

E-print Network

Nurse Rostering and Integer Programming Revisited John Thornton School of Information Technology and limited problem domains. In this paper, we consider a large, real world scheduling problem of nurse are introduced to evaluate the automated nurse schedules. Finally, we conclude that an integer programming

Thornton, John

164

VIRTUE EPISTEMOLOGY AND EPISTEMIC LUCK, REVISITED DUNCAN PRITCHARD  

E-print Network

1 VIRTUE EPISTEMOLOGY AND EPISTEMIC LUCK, REVISITED DUNCAN PRITCHARD ABSTRACT. In this paper I return to an argument that I presented in earlier work to the effect that virtue epistemology is at worse. KEYWORDS: Epistemology; Luck; Reliabilism; Virtue. 0. INTRODUCTION In recent worksee especially Pritchard

Edinburgh, University of

165

Multiprecision multiplication on AVR revisited Michael Hutter Peter Schwabe  

E-print Network

Multiprecision multiplication on AVR revisited Michael Hutter · Peter Schwabe July 31, 2014 Abstract This paper presents new speed records for multi- precision multiplication on the AVR ATmega family these speed records by care- fully optimizing the Karatsuba multiplication technique for AVR ATmega. One might

166

Geochemistry of the martian meteorite ALH84001, revisited  

E-print Network

1 Geochemistry of the martian meteorite ALH84001, revisited by Jean-Alix Barrat1,2 and Claire. Introduction In the absence of returned samples, the martian meteorites provide an unique opportunity martian meteorites have been identified. Most of them are shergottites or nakhlites. These rocks

Boyer, Edmond

167

Revisiting Maya Blue and Designing Hybrid Pigments by Archaeomimetism**  

E-print Network

1 Revisiting Maya Blue and Designing Hybrid Pigments by Archaeomimetism** Catherine Dejoie, Eric led several past civilizations to develop artificial pigments. Maya Blue (MB), manufactured in pre an archaeoinspired pigment, here indigo in a zeolite host, which satisfactorily reproduces the colour and chemical

Paris-Sud XI, Université de

168

A Theorem of Brny Revisited and Extended Nabil H. Mustafa  

E-print Network

A Theorem of Bárány Revisited and Extended Nabil H. Mustafa Department of Computer Science theorem [Bár82] states that given d + 1 sets of points in Rd , the convex hull of each containing of our results is the following exten- sion of the colorful Carathéodory theorem: given d/2 + 1 sets

Boyer, Edmond

169

Prediction of Prokaryotic Transcription Units from Microarray Data Revisited  

E-print Network

Prediction of Prokaryotic Transcription Units from Microarray Data Revisited Ulrich Bodenhofer, Wilhelm Lichtberger, Frank Klawonn In prokaryotic genomes, a transcription unit is a set of one or more co the knowledge about E.coli. For less investigated prokaryotes, it allows to infer hypotheses about transcription

Hochreiter, Sepp

170

Perceptual Issues in Augmented Reality Revisited Ernst Kruijff  

E-print Network

, handheld devices, mobile computing 1 INTRODUCTION Over the years, research on head-worn Augmented RealityPerceptual Issues in Augmented Reality Revisited Ernst Kruijff 1 J. Edward Swan II 2 Steven Feiner--Artificial, augmented, and virtual realities; H.5.2 [Infor- mation Interfaces and Presentation]: User Interfaces

Swan II, J. Edward

171

Revisiting Extinction in National Parks: Mountain Caribou in Banff  

E-print Network

's backcountry, Parks Canada staff dug a dead cari- bou (Rangifer tarandus) out of a snow avalancheDiversity Revisiting Extinction in National Parks: Mountain Caribou in Banff M. HEBBLEWHITE, C. This individual was likely the last southern mountain wood- land caribou, also a SARA-listed species, in the park

Hebblewhite, Mark

172

Ties Matter: Complexity of Voting Manipulation Revisited Svetlana Obraztsova  

E-print Network

Ties Matter: Complexity of Voting Manipulation Revisited Svetlana Obraztsova School of Physical, or, equivalently, that ties are broken in favor of the manipulator's preferred candidate that the algorithm presented in [1] extends to all rules that break ties according to a fixed ordering over

Elkind, Edith

173

DNA Compression Challenge Revisited: a Dynamic Programming Approach  

E-print Network

DNA Compression Challenge Revisited: a Dynamic Programming Approach Behshad Behzadi and Fabrice Le Fessant LIX, Ecole Polytechnique, Paris, FRANCE June 21 2005 B. Behzadi, F. Le Fessant (LIX) DNA Compression June 21 2005 1 / 38 #12;Outline 1 DNA Compression Challenge 2 Tools and Methods 3 DNA Compression

Lonardi, Stefano

174

Revisiting Multimode Coupled Bridge Flutter: Some New Insights  

E-print Network

Revisiting Multimode Coupled Bridge Flutter: Some New Insights Xinzhong Chen1 and Ahsan Kareem2 Abstract: Better understanding of the bimodal coupled bridge flutter involving fundamental vertical bending and torsional modes offers valuable insight into multimode coupled flutter, which has primarily been the major

Chen, Xinzhong

175

Revisiting the Role of Communication in Adolescent Intimate Partner Violence  

ERIC Educational Resources Information Center

A growing literature suggests that communication strategies can promote or inhibit intimate partner violence (IPV). Research on communication is still needed on a group ripe for early IPV intervention: high school-aged adolescents. This article revisits our previous analyses of young female reproductive clinic patients (Messinger, Davidson, &…

Messinger, Adam M.; Rickert, Vaughn I.; Fry, Deborah A.; Lessel, Harriet; Davidson, Leslie L.

2012-01-01

176

Hotelling Revisited: Oil Prices and Endogenous Technological Progress1  

E-print Network

Hotelling Revisited: Oil Prices and Endogenous Technological Progress1 C.-Y. Cynthia Lin,2 Haoying prices have been trendless despite resource scarcity. In particular, we examine how endoge- nous a constant market price for nonrenewable resources. We calibrate our model using empirical data on world oil

Lin, C.-Y. Cynthia

177

Innate phonetic boundaries revisited (L) Richard N. Aslina)  

E-print Network

Innate phonetic boundaries revisited (L) Richard N. Aslina) Department of Brain and Cognitive serious concerns with the so-called Universal Theory of phonetic category development that she the entire notion of phonetic categories. Here we argue that Nittrouer not only misrepresented Universal

Aslin, Richard N.

178

Obsidian provenance studies in Colombia and Ecuador: obsidian sources revisited  

Microsoft Academic Search

The field occurrences, elemental compositions and formation ages of Colombian and Ecuadorian obsidians are revisited. It is shown that the regional sources of this raw material are linked to two major volcanic structures: the Chacana and the Paletara calderas, localised on the eastern cordillera of Ecuador and on the central Andean cordillera of south Colombia respectively. Seventy-two samples were analysed

Ludovic Bellot-Gurlet; Olivier Dorighel; Gérard Poupeau

2008-01-01

179

Don't Give Yourself Away: Cooperation Revisited  

E-print Network

determined to reach a certain goal, a partner can have more social intelligence and be able to read the mindDon't Give Yourself Away: Cooperation Revisited Anton Nijholt University of Twente, Human Media possible elements of competitiveness. In these situations Grice's maxims on cooperation, i.e. assumptions

Nijholt, Anton

180

Genome Rearrangement and Planning: Revisited Tansel Uras and Esra Erdem  

E-print Network

Genome Rearrangement and Planning: Revisited Tansel Uras and Esra Erdem Faculty of Engineering be reconstructed by pair- wise comparison of their entire genomes. Such a comparison can be quantified by determining the number of events that change the order of genes in a genome. Earlier Erdem and Tillier

Erdem, Esra

181

Revisiting the dissociation between singing and speaking in expressive aphasia  

E-print Network

Revisiting the dissociation between singing and speaking in expressive aphasia Sylvie HeÃ?bert,1 Ame a severe expressive aphasia following a right-hemisphere stroke, but whose language comprehension from the operation of same mechanisms. Keywords: aphasia; melody intonation therapy; singing; songs

182

Educational Administration and the Management of Knowledge: 1980 Revisited  

ERIC Educational Resources Information Center

This paper revisits the thesis of a 1980 paper that suggested a new approach to educational administration based upon the New Sociology of Education. In particular it updates answers to the six key questions asked by that paper: what counts as knowledge; how is what counts as knowledge organised; how is what counts as knowledge transmitted; how is…

Bates, Richard

2013-01-01

183

Artificial Intelligence 120 (2000) 2942 Optimal auctions revisited 6  

E-print Network

Artificial Intelligence 120 (2000) 29­42 Optimal auctions revisited 6 Dov Monderer , Moshe. Tennenholtz / Artificial Intelligence 120 (2000) 29­42 game theory [5]. In particular, the design of protocols aspects of multi-agent activity in Artificial Intelligence has grown rapidly in the recent years. Work

Monderer, Dov

184

"An analysis of the classical Doppler Effect"[1] revisited  

E-print Network

After having shown that the formula which describes the Doppler effect in the general case holds only in the case of the "very high" frequency assumption, we derive free of assumptions Doppler formulas for two scenarios presented in the revisited paper.

Bernhard Rothenstein; Corina Nafornita

2004-03-26

185

Revisiting Size-Based Scheduling with Estimated Job Sizes  

E-print Network

, suggesting that size-based scheduling is effective only when the error on size estimation is small; knownRevisiting Size-Based Scheduling with Estimated Job Sizes Matteo Dell'Amico EURECOM, France Damiano errors on job size estimates, thus limiting the applicability of size-based schedulers. We show

Carra, Damiano

186

UNCORRECTED Natural enemy ravine revisited: the importance of  

E-print Network

UNCORRECTED PROOF Natural enemy ravine revisited: the importance of sample size for determining. It is concluded that the natural enemy ravine in the population dynamics of cereal aphids, identified by Southwood unless very large samples are taken. Key words. Cereal aphids, natural enemy ravine, population density

Kratochvíl, Lukas

187

Moral Judgment Development across Cultures: Revisiting Kohlberg's Universality Claims  

ERIC Educational Resources Information Center

This article revisits Kohlberg's cognitive developmental claims that stages of moral judgment, facilitative processes of social perspective-taking, and moral values are commonly identifiable across cultures. Snarey [Snarey, J. (1985). "The cross-cultural universality of social-moral development: A critical review of Kohlbergian research."…

Gibbs, John C.; Basinger, Karen S.; Grime, Rebecca L.; Snarey, John R.

2007-01-01

188

Magnetic Braking Revisited: Activities for the Undergraduate Laboratory  

ERIC Educational Resources Information Center

This paper revisits the demonstration of Lenz by dropping magnets down a non-magnetic tube. Recent publications are reviewed and ideas for undergraduate laboratory investigations are suggested. Finally, an example of matching theory to observation is presented. (Contains 4 tables, 5 figures and 3 footnotes.)

Ireson, Gren; Twidle, John

2008-01-01

189

"Interval Rational = Algebraic" Revisited: A More Computer Realistic Result  

E-print Network

numbers are represented. The set of all rational numbers is countable and has, therefore, Lebesgue measure"Interval Rational = Algebraic" Revisited: A More Computer Realistic Result Anatoly V. Lakeyev1 rational functions, then the resulting class of "interval-rational" functions practically coincides

Kreinovich, Vladik

190

The Soundex Phonetic Algorithm Revisited for SMS Text Representation  

E-print Network

The Soundex Phonetic Algorithm Revisited for SMS Text Representation David Pinto1, Darnes Vilariño1 has had a major social and technological impact such as the growing use of Short Message Services (SMS phones sending between 30 and 40 SMS at month. Hence the great importance of analyzing representation

Pinto, David Eduardo

191

Girl Number 20 Revisited: Feminist Literacies in New Hard Times  

ERIC Educational Resources Information Center

This paper revisits the question of "voice" in the context of neo-liberal social and educational reform. "Voice" has been one of the key concepts of feminist and critical pedagogies in the theory and practice of producing social transformation. I argue in this paper, that the political effectiveness of this concept needs to be reconsidered at a…

Gonick, Marnina

2007-01-01

192

Revisiting the Cramer-Rao Bound for Localization Algorithms  

E-print Network

Revisiting the Cramer-Rao Bound for Localization Algorithms S. Dulman and P. Havinga Pervasive the usage of lateration [6] and the associated Cramer-Rao Bound (CRB) [3], concepts borrowed from GPS the lateration technique we come across the concept of Cramer-Rao Bound applied to the localization problem [3

Langendoen, Koen

193

Minimum-Link Paths Revisited Joseph S. B. Mitchell  

E-print Network

Minimum-Link Paths Revisited Joseph S. B. Mitchell Valentin Polishchuk Mikko Sysikaski Abstract-vertex polygonal domain P with h holes, and two points s, t P; the goal is to find an s-t path with the fewest

194

Calculational reasoning revisited an Isabelle/Isar experience  

E-print Network

Calculational reasoning revisited an Isabelle/Isar experience Gertrud Bauer and Markus Wenzel://www.in.tum.de/bauerg/ http://www.in.tum.de/wenzelm/ Abstract. We discuss the general concept of calculational reasoning meta-logical framework of Isabelle, such as higher-order unification and resolution, calculational

Wenzel, Makarius "Markus"

195

Burr Type X Distribution: Revisited Mohammad Z. Raqab1  

E-print Network

Burr Type X Distribution: Revisited Mohammad Z. Raqab1 Debasis Kundu2 Abstract In this paper, we consider the two-parameter Burr-Type X distribution. We observe several interesting properties of this distribution. This particular skewed distribution can be used quite effectively in analyzing lifetime data

Kundu, Debasis

196

Revisiting Feminist Identity Development Theory, Research, and Practice  

ERIC Educational Resources Information Center

The model of feminist identity development proposed by Downing and Roush in 1985 is revisited as a potentially useful framework in counseling psychology theory, research, and practice. An examination of the historical context from which the model arose illustrates how it advanced theory in the psychology of women. A critical review of the extant…

Moradi, Bonnie; Subich, Linda Mezydlo; Phillips, Julia C.

2002-01-01

197

Sodium and potassium vapor Faraday filters revisited: theory and applications  

E-print Network

: 260.1440, 260.5430, 260.5740, 260.7490. 1. INTRODUCTION Extremely narrowband optical filtersSodium and potassium vapor Faraday filters revisited: theory and applications S. D. Harrell,1, * C vapor Faraday filters is developed. The dependence of the filter transmission on atomic density

198

The Frechet Distance Revisited and Extended Sariel Har-Peled  

E-print Network

1 The Fr´echet Distance Revisited and Extended Sariel Har-Peled Benjamin Raichel February 24, 2012 to compute curves (in each complex) between these vertices, such that the weak Fr´echet distance between these curves is minimized. As a polygonal curve is a complex, this generalizes the regular notion of weak Fr´echet

Har-Peled, Sariel

199

The Frechet Distance Revisited and Extended Sariel Har-Peled  

E-print Network

1 The Fr´echet Distance Revisited and Extended Sariel Har-Peled Benjamin Raichel March 8, 2011 to compute curves (in each complex) between these vertices, such that the Fr´echet distance between these curves is minimized. As a polygonal curve is a complex, this generalizes the regular notion of weak Fr´echet

Har-Peled, Sariel

200

Instructional Efficiency: Revisiting the Original Construct in Educational Research  

ERIC Educational Resources Information Center

This article revisits Paas and Van Merrienboer's (1993) measure of instructional efficiency, which can be applied by educational researchers to compare the effects of different instructional conditions on learning. This measure relied on performance and mental effort on the test, and as such gave an indication of the quality of learning outcomes.…

van Gog, Tamara; Paas, Fred

2008-01-01

201

Programming Revisited - The Educational Value of Computer Programming  

Microsoft Academic Search

This panel will address pedagogical needs for revisiting the role of computer programming for student learning. We will explore advances in programming platforms that enable students to create compelling projects with new technologies, and discuss the affordances of these new initiatives. We will address how these tools and techniques can be integrated into the curriculum of the classroom as well

Eric Klopfer; Mitchel Resnick; John Maloney; Brian Silverman; Andrew Begel; Chris Hancock

2004-01-01

202

December 2007December 2007 2121 Dutchwoman Butte Revisited  

E-print Network

December 2007December 2007 2121 Dutchwoman Butte Revisited Examining paradigms for livestock on the allotment is a 100-acre isolated landform (Photo 1) support- ing relict vegetation, Dutchwoman Butte (DWB%­40%) of perennial grasses than the grazed Photo 1. Dutchwoman Butte, a 100-acre isolated landform protected from

203

The root of the angiosperms revisited Michael J. Zanis  

E-print Network

The root of the angiosperms revisited Michael J. Zanis , Douglas E. Soltis§ , Pamela S. Soltis of basal angiosperms have converged on the placement of Amborella as sister to all other extant angiosperms to all remaining angiosperms or that Nymphaeales alone are the sister to the remaining angiosperms. We

Donoghue, Michael

204

The coordinate coherent states approach revisited  

SciTech Connect

We revisit the coordinate coherent states approach through two different quantization procedures in the quantum field theory on the noncommutative Minkowski plane. The first procedure, which is based on the normal commutation relation between an annihilation and creation operators, deduces that a point mass can be described by a Gaussian function instead of the usual Dirac delta function. However, we argue this specific quantization by adopting the canonical one (based on the canonical commutation relation between a field and its conjugate momentum) and show that a point mass should still be described by the Dirac delta function, which implies that the concept of point particles is still valid when we deal with the noncommutativity by following the coordinate coherent states approach. In order to investigate the dependence on quantization procedures, we apply the two quantization procedures to the Unruh effect and Hawking radiation and find that they give rise to significantly different results. Under the first quantization procedure, the Unruh temperature and Unruh spectrum are not deformed by noncommutativity, but the Hawking temperature is deformed by noncommutativity while the radiation specturm is untack. However, under the second quantization procedure, the Unruh temperature and Hawking temperature are untack but the both spectra are modified by an effective greybody (deformed) factor. - Highlights: Black-Right-Pointing-Pointer Suggest a canonical quantization in the coordinate coherent states approach. Black-Right-Pointing-Pointer Prove the validity of the concept of point particles. Black-Right-Pointing-Pointer Apply the canonical quantization to the Unruh effect and Hawking radiation. Black-Right-Pointing-Pointer Find no deformations in the Unruh temperature and Hawking temperature. Black-Right-Pointing-Pointer Provide the modified spectra of the Unruh effect and Hawking radiation.

Miao, Yan-Gang, E-mail: miaoyg@nankai.edu.cn; Zhang, Shao-Jun, E-mail: sjzhang@mail.nankai.edu.cn

2013-02-15

205

Finite frequency tomography: the checkerboard test revisited  

NASA Astrophysics Data System (ADS)

We address some consequences of the application of finite frequency theory for seismic tomography by revisiting the classical checkerboard test. We use a simple borehole-to-borehole experiment set-up in order to have complete control of the situation and to avoid complicating factors such as crustal corrections that still hamper global tomography. We are particularly interested in the feasibility of using ray-based finite frequency kernels in the inversion of travel time perturbations measured by crosscorrelation, in the cross-dependence between S wave velocity perturbations and the measured P travel times, and in the benefits of using finite-frequency theory on one or multiple frequency bands. We have done a 3D checkerboard test to assess the influence of these issues. Full-waveform synthetic seismograms are calculated using the spectral elements method up to 2 kHz maximum frequency. The computational domain extends 200 m x 120 m x 120 m and the target velocity model is a checkerboard with 12 m x 12 m x 12 m blocks of velocities 5% slower and faster than the background (homogeneous, Vp=6 km/s) model. First, we make a comparison between finite-frequency kernels calculated by ray theory with those based on the spectral elements method (adjoint technique), in terms of resolution, accuracy, but also computational cost. From synthetic seismograms calculated for the 3D checkerboard model as well as for the homogeneous model, we measure crosscorrelation travel times at different frequency bands and invert them with classical ray theory as well as with finite frequency theory. Several interesting features are highlighted in our multi-band data set, such as the wavefront healing effect. For instance, we observe that the delay times, in absolute value, are usually larger at short (0.5 ms) than long (4 ms) periods. This can be explained by the presence of the "doughnut hole" along the geometrical ray path in the sensitivity kernels, whose diameter is proportional to the period. Thus, as the period increases, the anomalies are able to "hide" inside the growing "doughnut hole". When a single frequency band is interpreted using ray theory (infinite frequency approximation), the fact that wavefront healing is not taken into account has a disastrous effect, in particular on the imaging of blocks that are somewhat smaller than the Fresnel zone. When interpreting the same data set with finite-frequency theory we do much better, especially in the center of the model where Fresnel zones are widest. Adding a range of frequencies in the inversion (i.e. taking body wave dispersion into account) significantly increases resolution.

Mercerat, E. D.; Zaroli, C.; Nolet, G.

2011-12-01

206

Keyboard Acoustic Emanations Revisited LI ZHUANG, FENG ZHOU, and J. D. TYGAR  

E-print Network

3 Keyboard Acoustic Emanations Revisited LI ZHUANG, FENG ZHOU, and J. D. TYGAR University of California, Berkeley We examine the problem of keyboard acoustic emanations. We present a novel attack taking acoustic emanations revisited. ACM Trans. Info. Syst. Sec. 13, 1, Article 3 (October 2009), 26 pages. DOI

Tygar, Doug

207

Destination Image, Novelty, Hedonics, Perceived Value, and Revisiting Behavioral Intention for Island Tourism  

Microsoft Academic Search

This paper examines tourists’ experience of island tourism and investigates the causal relationships between the destination image, novelty, hedonics, perceived value, and revisiting behavioral intention. A total of 355 respondents completed a survey conducted on Green Island (Lyudao in Chinese), Taiwan. Using structural equation modeling, the results of the analysis supported the proposed revisiting behavioral intention model as follows: (1)

Tien-Ming Cheng; Chiang-Chuan Lu

2012-01-01

208

Convolution Operators in White Noise Calculus: Revisited (joint work with H. Ouerdiane)  

E-print Network

. . Convolution Operators in White Noise Calculus: Revisited (joint work with H. Ouerdiane) Nobuaki Operators in White Noise Calculus: Revisited Levico, June 1, 2011 1 / 35 #12;Plan [0] 1 Backgrounds 2 White Noise Distributions Boson Fock Space White Noise Triples Construction of Underlying Gelfand Triple

Obata, Nobuaki

209

IODINE IN THE ENVIRONMENT REVISITED. AN EVALUATION OF THE CHEMICAL-AND PHYSICO CHEMICAL  

E-print Network

IODINE IN THE ENVIRONMENT REVISITED. AN EVALUATION OF THE CHEMICAL- AND PHYSICO CHEMICAL PROCESSES-M-2791 IODINE IN THE ENVIRONMENT REVISITED. AN EVALUATION OF THE CHEMICAL- AND PHYSICO CHEMICAL PROCESSES, under physical and chemical conditions normally prevailing, exist as iodide. No evidence for a direct

210

Frontiers of Language and Teaching ............................................................. Volume 3 (2012) Revisiting Foreign Language Teacher Beliefs  

E-print Network

, grammar teaching, teacher and student role expectations, testing innovation, the use of L1 (mother tongue ............................................................. Volume 3 (2012) 190 Revisiting Foreign Language Teacher Beliefs Zehra Gabillon Laboratoire EA Sociétés.gabillon@gmail.com Abstract This state of the art paper revisits foreign language teacher beliefs. The first part of the paper

Paris-Sud XI, Université de

211

Topological Twisted Sigma Model with H-flux Revisited  

SciTech Connect

In this paper we revisit the topological twisted sigma model with H-flux. We explicitly expand and then twist the worldsheet Lagrangian for bi-Hermitian geometry. we show that the resulting action consists of a BRST exact term and pullback terms, which only depend on one of the two generalized complex structures and the B-field. We then discuss the topological feature of the model.

Chuang, Wu-yen

2006-08-18

212

Indoor air and human health revisited: A recent IAQ symposium  

SciTech Connect

Indoor Air and Human Health Revisited was a speciality symposium examining the scientific underpinnings of sensory and sensitivity effects, allergy and respiratory disease, neurotoxicity and cancer. An organizing committee selected four persons to chain the sessions and invite experts to give state-of-the-art presentations that will be published as a book. A summary of the presentations is made and some critical issues identified.

Gammage, R.B.

1994-12-31

213

DTI-measured white matter abnormalities in adolescents with Conduct Disorder.  

PubMed

Emerging research suggests that antisocial behavior in youth is linked to abnormal brain white matter microstructure, but the extent of such anatomical connectivity abnormalities remain largely untested because previous Conduct Disorder (CD) studies typically have selectively focused on specific frontotemporal tracts. This study aimed to replicate and extend previous frontotemporal diffusion tensor imaging (DTI) findings to determine whether noncomorbid CD adolescents have white matter microstructural abnormalities in major white matter tracts across the whole brain. Seventeen CD-diagnosed adolescents recruited from the community were compared to a group of 24 non-CD youth which did not differ in average age (12-18) or gender proportion. Tract-based spatial statistics (TBSS) fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) measurements were compared between groups using FSL nonparametric two-sample t test, clusterwise whole-brain corrected, p < .05. CD FA and AD deficits were widespread, but unrelated to gender, verbal ability, or CD age of onset. CD adolescents had significantly lower FA and AD values in frontal lobe and temporal lobe regions, including frontal lobe anterior/superior corona radiata, and inferior longitudinal and fronto-occipital fasciculi passing through the temporal lobe. The magnitude of several CD FA deficits was associated with number of CD symptoms. Because AD, but not RD, differed between study groups, abnormalities of axonal microstructure in CD rather than myelination are suggested. This study provides evidence that adolescent antisocial disorder is linked to abnormal white matter microstructure in more than just the uncinate fasciculus as identified in previous DTI studies, or frontotemporal brain structures as suggested by functional neuroimaging studies. Instead, neurobiological risk specific to antisociality in adolescence is linked to microstructural abnormality in numerous long-range white matter connections among many diverse different brain regions. PMID:24139595

Haney-Caron, Emily; Caprihan, Arvind; Stevens, Michael C

2014-01-01

214

Cerebral grey, white matter and csf in never-medicated, first-episode schizophrenia.  

PubMed

We report the first voxel-based morphometric (VBM) study to examine cerebral grey and white matter and cerebrospinal fluid (CSF) using computational morphometry in never-medicated, first-episode psychosis (FEP). Region-of-interest (ROI) analysis was also performed blind to group membership. 26 never-medicated individuals with FEP (23 with DSM-IV schizophrenia) and 38 healthy controls had MRI brain scans. Groups were balanced for age, sex, handedness, ethnicity, paternal socio-economic status, and height. Healthy controls were recruited from the local community by advertisement. Grey matter, white matter, and CSF: global brain volume ratios were significantly smaller in patients. Patients had significantly less grey matter volume in L and R caudate nuclei, cingulate gyri, parahippocampal gyri, superior temporal gyri, cerebellum and R thalamus, prefrontal cortex. They also had significantly less white matter volume in the R anterior limb of the internal capsule fronto-occipital fasciculus and L and R fornices, and significantly greater CSF volume especially in the R lateral ventricle. Excluding the 3 subjects with brief psychotic disorder did not alter our results. Our data suggest that fronto-temporal and subcortical-limbic circuits are morphologically abnormal in never-medicated, schizophrenia. ROI analysis comparing the schizophrenia group (n=23) with the healthy controls (n=38) confirmed caudate volumes were significantly smaller bilaterally by 11%, and lateral ventricular volume was significantly larger on the right by 26% in the patients. Caudate nuclei and lateral ventricular volume measurements were uncorrelated (Pearson correlation coefficient 0.30, p=0.10), ruling out the possibility of segmentation artefact. Ratio of lateral ventricle to caudate volume was bilaterally significantly increased (p<0.005, 2-tailed), which could represent an early biomarker in first-episode, never-medicated schizophrenia. PMID:17098398

Chua, Siew E; Cheung, Charlton; Cheung, Vinci; Tsang, Jack T K; Chen, Eric Y H; Wong, Jason C H; Cheung, Jason P Y; Yip, Lawrance; Tai, Kin-Shing; Suckling, John; McAlonan, Gráinne M

2007-01-01

215

Neuroanatomical pattern classification in a population-based sample of first-episode schizophrenia.  

PubMed

Recent neuroanatomical pattern classification studies have attempted to individually classify cases with psychotic disorders using morphometric MRI data in an automated fashion. However, this approach has not been tested in population-based samples, in which variable patterns of comorbidity and disease course are typically found. We aimed to evaluate the diagnostic accuracy (DA) of the above technique to discriminate between incident cases of first-episode schizophrenia identified in a circumscribed geographical region over a limited period of time, in comparison with next-door healthy controls. Sixty-two cases of first-episode schizophrenia or schizophreniform disorder and 62 age, gender and educationally-matched controls underwent 1.5 T MRI scanning at baseline, and were naturalistically followed-up over 1 year. T1-weighted images were used to train a high-dimensional multivariate classifier, and to generate both spatial maps of the discriminative morphological patterns between groups and ROC curves. The spatial map discriminating first-episode schizophrenia patients from healthy controls revealed a complex pattern of regional volumetric abnormalities in the former group, affecting fronto-temporal-occipital gray and white matter regions bilaterally, including the inferior fronto-occipital fasciculus, as well as the third and lateral ventricles. However, an overall modest DA (73.4%) was observed for the individual discrimination between first-episode schizophrenia patients and controls, and the classifier failed to predict 1-year prognosis (remitting versus non-remitting course) of first-episode schizophrenia (DA=58.3%). In conclusion, using a "real world" sample recruited with epidemiological methods, the application of a neuroanatomical pattern classifier afforded only modest DA to classify first-episode schizophrenia subjects and next-door healthy controls, and poor discriminative power to predict the 1-year prognosis of first-episode schizophrenia. PMID:23261522

Zanetti, Marcus V; Schaufelberger, Maristela S; Doshi, Jimit; Ou, Yangming; Ferreira, Luiz K; Menezes, Paulo R; Scazufca, Marcia; Davatzikos, Christos; Busatto, Geraldo F

2013-06-01

216

Neuroanatomical Changes due to Hearing Loss and Chronic Tinnitus: A Combined VBM and DTI Study  

PubMed Central

Subjective tinnitus is the perception of sound in the absence of an external source. Tinnitus is often accompanied by hearing loss but not everyone with hearing loss experiences tinnitus. We examined neuroanatomical alterations associated with hearing loss and tinnitus in three groups of subjects: those with hearing loss with tinnitus, those with hearing loss without tinnitus and normal hearing controls without tinnitus. To examine changes in gray matter we used structural MRI scans and voxel-based morphometry (VBM) and to identify changes in white matter tract orientation we used diffusion tensor imaging (DTI). A major finding of our study was that there were both gray and white matter changes in the vicinity of the auditory cortex for subjects with hearing loss alone relative to those with tinnitus and those with normal hearing. We did not find significant changes in gray or white matter in subjects with tinnitus and hearing loss compared to normal hearing controls. VBM analysis revealed that individuals with hearing loss without tinnitus had gray matter decreases in anterior cingulate and superior and medial frontal gyri relative to those with hearing loss and tinnitus. Region-of-interest analysis revealed additional decreases in superior temporal gyrus for the hearing loss group compared to the tinnitus group. Investigating effects of hearing loss alone, we found gray matter decreases in superior and medial frontal gyri in participants with hearing loss compared to normal hearing controls. DTI analysis showed decreases in fractional anisotropy values in the right superior and inferior longitudinal fasciculi, corticospnial tract, inferior fronto-occipital tract, superior occipital fasciculus, and anterior thalamic radiation for the hearing loss group relative to normal hearing controls. In attempting to dissociate the effect of tinnitus from hearing loss, we observed that hearing loss rather than tinnitus had the greatest influence on gray and white matter alterations. PMID:21047501

Husain, Fatima T.; Medina, Roberto E.; Davis, Caroline W.; Szymko-Bennett, Yvonne; Simonyan, Kristina; Pajor, Nathan M.; Horwitz, Barry

2010-01-01

217

Revisiting a Constructive Classic: Wright's Physical Disability: A Psychosocial Approach  

PubMed Central

Beatrice A. Wright's (1960) classic book, Physical Disability: A Psychological Approach is a landmark publication in rehabilitation psychology. The authors believe that Division 22's forthcoming 50th anniversary, the results of a recent survey on essential readings in rehabilitation psychology, and a public critique concerning the relevance of individuating language in psychology are compelling reasons for revisiting the influence of Physical Disability. After discussing these catalysts, the authors review the book's history, scholarly impact, and link to positive disciplinary directions. The authors conclude by encouraging rehabilitation psychologists and other members of the discipline to (re)acquaint themselves with this important book and the timeless concepts it espouses. PMID:19079791

Dunn, Dana S.; Elliott, Timothy R.

2008-01-01

218

Revisiting User Simulation in Dialogue Systems. Do we still need them?  

E-print Network

Revisiting User Simulation in Dialogue Systems. Do we still need them? Will imitation play the role came into our lives stayed for ever. It is with that sense I am writing this note at the end of my work

Paris-Sud XI, Université de

219

Counterion Condensation in DNA Systems: The Cylindrical Poisson-Boltzmann Model Revisited  

E-print Network

Counterion Condensation in DNA Systems: The Cylindrical Poisson-Boltzmann Model Revisited E 110016, India Nucleic acids are highly charged systemsand counterions condense on the negatively charged phosphates, imparting electrostatic stability to the system.' This counterion condensation (CC) hypothesis

Jayaram, Bhyravabotla

220

Revisiting the block method for evaluating thermal conductivities of clay and granite  

Technology Transfer Automated Retrieval System (TEKTRAN)

Determination of thermal conductivities of porous media using the contact method is revisited and revalidated with consideration of thermal contact resistance. Problems that limit the accuracy of determination of thermal conductivities of porous media are discussed. Thermal conductivities of granite...

221

Aristotle's Square Revisited to Frame Discovery Mohammad Afshar, Christopher Dartnell, Dominique Luzeaux, Jean Sallantin, Yannick Tognetti  

E-print Network

Aristotle's Square Revisited to Frame Discovery Science Mohammad Afshar, Christopher Dartnell This paper uses the terminol- ogy from paraconsistent logic and paracomplete logic that extends Aristotle molecules. Index Terms-- Machine Learning, Scientific Method, Logical Reasoning Framework, Aristotle

Paris-Sud XI, Université de

222

Revisiting Calendar Anomalies in Asian Stock Markets Using a Stochastic Dominance Approach  

E-print Network

Revisiting Calendar Anomalies in Asian Stock Markets Using a Stochastic Dominance Approach Hooi Abstract Extensive evidence on the prevalence of calendar effects suggests that there exist abnormal returns. Some recent studies, however, have concluded that calendar effects have largely disappeared

Chaudhuri, Sanjay

223

Occupational asthma and occupational rhinitis: The united airways disease model revisited  

E-print Network

1 Occupational asthma and occupational rhinitis: The united airways disease model revisited Jacques number: +33147107754; Fax number:+33147107768 Key words: occupational asthma, occupational rhinitis, high) Objectives: Whereas accumulating evidence indicates close associations between rhinitis and asthma, little

Boyer, Edmond

224

Revisiting Monte-Carlo Tree Search on a Normal Form Game: NoGo  

E-print Network

Revisiting Monte-Carlo Tree Search on a Normal Form Game: NoGo C.-W. Chou2 ,O. Teytaud1 , S.-J. Yen, Taiwan. Abstract. We revisit Monte-Carlo Tree Search on a recent game, termed NoGo. Our goal is to check on a new game. We also test if the known limitations of Monte-Carlo Tree Search also hold in this case

Paris-Sud XI, Université de

225

The contact of elastic regular wavy surfaces revisited  

E-print Network

We revisit the classic problem of an elastic solid with a two-dimensional wavy surface squeezed against an elastic flat half-space from infinitesimal to full contact. Through extensive numerical calculations and analytic derivations, we discover previously overlooked transition regimes. These are seen in particular in the evolution with applied load of the contact area and perimeter, the mean pressure and the probability density of contact pressure. These transitions are correlated with the contact area shape, which is affected by long range elastic interactions. Our analysis has implications for general random rough surfaces, as similar local transitions occur continuously at detached areas or coalescing contact zones. We show that the probability density of null contact pressures is non-zero at full contact. This might suggest revisiting the conditions necessary for applying Persson's model at partial contacts and guide the comparisons with numerical simulations. We also address the evaluation of the contact perimeter for discrete geometries and the applicability of Westergaard's solution for three-dimensional geometries.

Vladislav A. Yastrebov; Guillaume Anciaux Jean-Francois Molinari

2014-09-05

226

Artifact quantification and tractography from 3T MRI after placement of aneurysm clips in subarachnoid hemorrhage patients  

PubMed Central

Background The application of advanced 3T MRI imaging techniques to study recovery after subarachnoid hemorrhage (SAH) is complicated by the presence of image artifacts produced by implanted aneurysm clips. To characterize the effect of these artifacts on image quality, we sought to: 1) quantify extent of image artifact in SAH patients with implanted aneurysm clips across a range of MR sequences typically used in studies of volumetry, blood oxygen level dependent signal change (BOLD-fMRI), and diffusion-weighted imaging (DW-MRI) and 2) to explore the ability to reconstruct white matter pathways in these patients. Methods T1- and T2-weighted structural, BOLD-fMRI, and DW-MRI scans were acquired at 3T in two patients with titanium alloy clips in ACOM and left ACA respectively. Intensity-based planimetric contouring was performed on aligned image volumes to define each artifact. Artifact volumes were quantified by artifact/clip length and artifact/brain volume ratios and analyzed by two-way (scan-by-rater) ANOVAs. Tractography pathways were reconstructed from DW-MRI at varying distances from the artifacts using deterministic methods. Results Artifact volume varied by MR sequence for length (p = 0.007) and volume (p < 0.001) ratios: it was smallest for structural images, larger for DW-MRI acquisitions, and largest on fMRI images. Inter-rater reliability was high (r = 0.9626, p < 0.0001), and reconstruction of white matter connectivity characteristics increased with distance from the artifact border. In both patients, reconstructed white matter pathways of the uncinate fasciculus and inferior fronto-occipital fasciculus were clearly visible within 2 mm of the artifact border. Conclusions Advanced 3T MR can successfully image brain tissue around implanted titanium aneurysm clips at different spatial ranges depending on sequence type. White matter pathways near clip artifacts can be reconstructed and visualized. These findings provide a reference for designing functional and structural neuroimaging studies of recovery in aSAH patients after clip placement. PMID:21970560

2011-01-01

227

Revisited modeling of Titan’s middle atmosphere electrical conductivity  

NASA Astrophysics Data System (ADS)

The atmospheric electrical conductivity measured by the Permittivity, Wave and Altimetry (PWA) subsystem on board the Huygens probe, during the landing mission on Titan, has been modeled in the present work. Previous modeling studies showed a Galactic Cosmic Ray (GCR) peak of conductivity at a higher altitude and a quantitative overestimation in the altitude range 0-100 km compared to that observed by the PWA instrument. Recently the PWA data was revisited and provided new constraints on the conductivity at altitudes 100-180 km. Because the aerosols in the atmosphere are known to alter the electron concentration, using a detailed distribution of the aerosols at all altitudes, the electron conductivity has been calculated in the altitude range 0-180 km. By using a variable range of photoemission threshold for the aerosols, the present model is able to reasonably predict the altitude at which the GCR peak of conductivity occurs and to meet the new constraints for the conductivity profile.

Mishra, Alabhya; Michael, Marykutty; Tripathi, Sachchida Nand; Béghin, Christian

2014-08-01

228

Quasi-particle model of QGP - a revisit  

E-print Network

The quasi-particle model of quark gluon plasma (QGP) is revisited here with thermodynamically consistent formalism, different from earlier studies, without the need of temperature dependent bag constant as well as other effects such as confinement effects, effective degrees of freedom etc. Our model has only one system dependent parameter and surpraisingly good fit to lattice results for gluon plasma, 2-flavor and 3-flavor QGP are obtained. The basic idea is to evaluate energy density $\\epsilon$ first from grand partition function of quasi-particle QGP and then derive all other thermodynamic functions from $\\epsilon$. Quasi-particles are assumed to have temperature dependent mass equal to plasma frequency. Energy density, pressure and speed of sound are evaluated and compared with available lattice data. We further extend the model to finite chemical potential, without any new parameters, to obtain quark density, quark susceptibility etc. and fits very well with the lattice results on 2-flavor QGP.

Vishnu M. Bannur

2005-08-05

229

Revisiting symmetries of lattice fermions via spin-flavor representation  

E-print Network

Employing the spin-flavor representation, we investigate the structures of the doubler-mixing symmetries and the mechanisms of their spontaneous breakdown in four types of lattice fermion formulation. We first revisit the $U(4)\\timesU(4)A$ symmetries of the naive fermion with the vanishing bare mass m, and re-express them in terms of the spin-flavor representation. We apply the same method to the Wilson fermion, which possesses only the U(1) vector symmetry for general values of m. For a special value of m, however, there emerges an additional U(1) symmetry to be broken by pion condensation. We also explore two types of minimally doubled fermion, and discover a similar kind of symmetry enhancement and its spontaneous breakdown.

Taro Kimura; Shota Komatsu; Tatsuhiro Misumi; Toshifumi Noumi; Shingo Torii; Sinya Aoki

2011-12-23

230

Iron under pressure: bcc-hcp equilibrium coexistence revisited  

E-print Network

We revisit results from decades of pressure experiments on the bcc - hcp transformations in iron, which are sensitive to non-hydrostatic conditions and sample size. We emphasize the role of martensitic stress in the observed pressure hysteresis and address the large spread in values for onset pressures of the nucleating phase. From electronic-structure calculations, we find a bcc - hcp equilibrium coexistence pressure of 8.4 GPa. Accounting for non-hydrostatic martensitic stress and a stress-dependent transition barrier, we suggest a pressure inequality for better comparison to experiment and observed hysteresis. We construct the equation of state for bcc and hcp phases under hydrostatic pressure, and compare to experiments and previous calculations.

Zarkevich, Nikolai A

2014-01-01

231

Revisiting Noether gauge symmetry approach in quintom cosmology  

E-print Network

The Noether gauge symmetry approach is revisited to study various quintom scenarios (those that arise by the presence of two dynamical scalar fields) to comprehend the role of dark energy in our universe. For such models, we obtain smooth parameterizations of the equation of state of dark energy across the boundary of cosmological constant $w_{\\Lambda}=-1$. This study gives rise to two new cases of the potential $V(\\phi, \\sigma)$, due to a quintom field in which nonlinear coupling of the scalar fields arise. Besides we report that a few cases of Noether gauge symmetries and their invariants in [Adnan Aslam, et. al., Astrophys Space Sci (2013), 348:533-540] are incorrect. Consequently, the given cosmological model in their paper is not a feasible quintom model.

Ali, Sajid

2015-01-01

232

Revisiting Public Health Challenges in the New Millennium  

PubMed Central

Positive Health of the communities could only be brought out through the interrelationship between conventional health sector and other development sectors. It was a dream that came true when World Health Organization (WHO) accepted Primary Health Care (PHC) as the major tool to achieve its proposed goal of Health For All (HFA) by 2000 A.D., but we could not succeed as expected. Now we have the Millennium Development Goals (MDG), which place health at the heart of development but the achievements in health is still challenging. The literature search in this article has been conducted in Pub Med and Google scholar, with the aim to draw references to discuss the major health issues and ways to tackle them. The current article briefly narrates the burden and complexities of challenges faced by the present global health. Revisiting the concept of PHC and reaffirming our solidarity to this philosophy is the need of this hour. PMID:24116303

Anish, TS; Sreelakshmi, PR

2013-01-01

233

Tidal Disruption Revisited - Creating Bifurcated Shapes Among Rubble Pile Asteroids  

NASA Astrophysics Data System (ADS)

We revisit the tidal disruption of rubble pile asteroids encountering terrestrial planets. The rubble pile structure of the asteroid is modeled with spherical particles that interact with full ``soft-sphere'' descriptions of the particles interactions - including static, sliding, and rolling friction. Using friction parameters that have matched the behavior of irregularly shaped gravel particles dynamically evolving [1], we have run a suite of tidal disruption simulations to compare with previous simulations that used more simplistic particle interactions. We find that the soft-sphere description of the asteroids's mechanics is very important and dramatically change the dynamics of the disruption, particularly the resulting shapes of remnants. Here we find many elongated and bifurcated shapes, reminiscent of some of the irregularly shaped bodies recently imaged with delay-doppler radar.[1] Yu, Y. et al. 2014, Icarus, 10.1016/j.icarus.2014.07.027

Walsh, Kevin J.; Richardson, Derek C.; Schwartz, Stephen R.

2014-11-01

234

Response variance in functional maps: neural darwinism revisited.  

PubMed

The mechanisms by which functional maps and map plasticity contribute to cortical computation remain controversial. Recent studies have revisited the theory of neural Darwinism to interpret the learning-induced map plasticity and neuronal heterogeneity observed in the cortex. Here, we hypothesize that the Darwinian principle provides a substrate to explain the relationship between neuron heterogeneity and cortical functional maps. We demonstrate in the rat auditory cortex that the degree of response variance is closely correlated with the size of its representational area. Further, we show that the response variance within a given population is altered through training. These results suggest that larger representational areas may help to accommodate heterogeneous populations of neurons. Thus, functional maps and map plasticity are likely to play essential roles in Darwinian computation, serving as effective, but not absolutely necessary, structures to generate diverse response properties within a neural population. PMID:23874733

Takahashi, Hirokazu; Yokota, Ryo; Kanzaki, Ryohei

2013-01-01

235

Response Variance in Functional Maps: Neural Darwinism Revisited  

PubMed Central

The mechanisms by which functional maps and map plasticity contribute to cortical computation remain controversial. Recent studies have revisited the theory of neural Darwinism to interpret the learning-induced map plasticity and neuronal heterogeneity observed in the cortex. Here, we hypothesize that the Darwinian principle provides a substrate to explain the relationship between neuron heterogeneity and cortical functional maps. We demonstrate in the rat auditory cortex that the degree of response variance is closely correlated with the size of its representational area. Further, we show that the response variance within a given population is altered through training. These results suggest that larger representational areas may help to accommodate heterogeneous populations of neurons. Thus, functional maps and map plasticity are likely to play essential roles in Darwinian computation, serving as effective, but not absolutely necessary, structures to generate diverse response properties within a neural population. PMID:23874733

Takahashi, Hirokazu; Yokota, Ryo; Kanzaki, Ryohei

2013-01-01

236

Revisiting Johnson and Jackson boundary conditions for granular flows  

SciTech Connect

In this article, we revisit Johnson and Jackson boundary conditions for granular flows. The oblique collision between a particle and a flat wall is analyzed by adopting the classic rigid-body theory and a more realistic semianalytical model. Based on the kinetic granular theory, the input parameter for the partial-slip boundary conditions, specularity coefficient, which is not measurable in experiments, is then interpreted as a function of the particle-wall restitution coefficient, the frictional coefficient, and the normalized slip velocity at the wall. An analytical expression for the specularity coefficient is suggested for a flat, frictional surface with a low frictional coefficient. The procedure for determining the specularity coefficient for a more general problem is outlined, and a working approximation is provided.

Li, Tingwen; Benyahia, Sofiane

2012-07-01

237

Quantization table design revisited for image/video coding.  

PubMed

Quantization table design is revisited for image/video coding where soft decision quantization (SDQ) is considered. Unlike conventional approaches, where quantization table design is bundled with a specific encoding method, we assume optimal SDQ encoding and design a quantization table for the purpose of reconstruction. Under this assumption, we model transform coefficients across different frequencies as independently distributed random sources and apply the Shannon lower bound to approximate the rate distortion function of each source. We then show that a quantization table can be optimized in a way that the resulting distortion complies with certain behavior. Guided by this new design principle, we propose an efficient statistical-model-based algorithm using the Laplacian model to design quantization tables for DCT-based image coding. When applied to standard JPEG encoding, it provides more than 1.5-dB performance gain in PSNR, with almost no extra burden on complexity. Compared with the state-of-the-art JPEG quantization table optimizer, the proposed algorithm offers an average 0.5-dB gain in PSNR with computational complexity reduced by a factor of more than 2000 when SDQ is OFF, and a 0.2-dB performance gain or more with 85% of the complexity reduced when SDQ is ON. Significant compression performance improvement is also seen when the algorithm is applied to other image coding systems proposed in the literature. PMID:25248184

Yang, En-Hui; Sun, Chang; Meng, Jin

2014-11-01

238

Revisiting cosmic no-hair theorem for inflationary settings  

NASA Astrophysics Data System (ADS)

In this work we revisit Wald’s cosmic no-hair theorem [R. M. Wald, Phys. Rev. DPRVDAQ0556-2821 28, 2118 (1983).10.1103/PhysRevD.28.2118] in the context of accelerating Bianchi cosmologies for a generic cosmic fluid with nonvanishing anisotropic stress tensor and when the fluid energy-momentum tensor is of the form of a cosmological constant term plus a piece which does not respect strong or dominant energy conditions. Such a fluid is the one appearing in inflationary models. We show that for such a system anisotropy may grow, in contrast to the cosmic no-hair conjecture. In particular, for a generic inflationary model we show that there is an upper bound on the growth of anisotropy. For slow-roll inflationary models, our analysis can be refined further and the upper bound is found to be of the order of slow-roll parameters. We examine our general discussions and our extension of Wald’s theorem for three classes of slow-roll inflationary models, generic multiscalar field driven models, anisotropic models involving U(1) gauge fields and the gauge-flation scenario.

Maleknejad, A.; Sheikh-Jabbari, M. M.

2012-06-01

239

Revisiting the quantum Szilard engine with fully quantum considerations  

E-print Network

By considering level shifting during the insertion process we revisit the quantum Szilard engine (QSZE) with fully quantum consideration. We derive the general expressions of the heat absorbed from thermal bath and the total work done to the environment by the system in a cycle with two different cyclic strategies. We find that only the quantum information contributes to the absorbed heat, and the classical information acts like a feedback controller and has no direct effect on the absorbed heat. This is the first demonstration of the different effects of quantum information and classical information for extracting heat from the bath in the QSZE. Moreover, when the well width $L\\rightarrow \\infty $ or the temperature of the bath $T\\rightarrow \\infty $ the QSZE reduces to the classical Szilard engine (CSZE), and the total work satisfies the relation $W_{\\mathtt{tot}}=k_{B}T \\mathtt{ln}2$ as obtained by Sang Wook Kim et al. [Phys. Rev. Lett. 106, 070401 (2011)] for one particle case.

Hai Li; Jian Zou; Jun-Gang Li; Bin Shao; Lian-Ao Wu

2012-08-30

240

Revisiting heritability accounting for shared environmental effects and maternal inheritance.  

PubMed

Heritability measures the proportion of phenotypic variation attributable to genetic factors. In addition to a shared nuclear genetic component, a number of additional variance components, such as spousal correlation, sibship, household and maternal effects, may have strong contributions to inter-individual phenotype variation. In humans, the confounding effects of these components on heritability have not been studied thoroughly. We sought to obtain unbiased heritability estimates for complex traits in the presence of multiple variance components and also to estimate the contributions of these variance components to complex traits. We compared regression and variance component methods to estimate heritability in simulations when additional variance components existed. We then revisited heritability for several traits in Framingham Heart Study (FHS) participants. Using simulations, we found that failure to account for or misclassification of necessary variance components yielded biased heritability estimates. The direction and magnitude of the bias varied depending on a variance structure and an estimation method. Using the best fitted models to account for necessary variance components, we found that heritability estimates for most FHS traits were overestimated, ranging from 4 to 47 %, when we compared models that considered necessary variance components to models that only considered familial relationships. Spousal correlation explained 14-36 % of phenotypic variation in several anthropometric and lifestyle traits. Maternal and sibling effects also contributed to phenotypic variation, ranging from 3 to 5 % and 4 to 7 %, respectively, in several anthropometric and metabolic traits. Our findings may explain, in part, the missing heritability for some traits. PMID:25381465

Liu, Chunyu; Dupuis, Josée; Larson, Martin G; Cupples, L Adrienne; Ordovas, Jose M; Vasan, Ramachandran S; Meigs, James B; Jacques, Paul F; Levy, Daniel

2015-02-01

241

Masses and Gravities of Blue Horizontal Branch Stars Revisited  

E-print Network

Previous spectroscopic analyses of Blue Horizontal Branch (BHB) stars in six globular clusters revealed too low masses in four clusters when compared to canonical evolutionary theory, while the masses of the BHB stars in NGC 6752 and M 5 are found to be consistent with theory. We recalculated BHB star masses using new cluster distances derived by Reid (1997a,b) from HIPPARCOS parallaxes of local subdwarfs by main sequence fitting. The new distances are larger than previous estimates resulting in larger masses for the BHB stars. Since the increase in distance is small for NGC 6752 and M 5, the agreement with predicted masses persists. For M 15 and M 92 the masses now come into good agreement with theoretical predictions, while for NGC 288 and NGC 6397 the mass deficit is reduced but the BHB star masses remain slightly too low. Previous spectroscopic analyses also highlighted the problem of too low gravities for some BHB stars. The gravities and absolute magnitudes of BHB stars are revisited in the light of new evolutionary Horizontal Branch models.

U. Heber; S. Moehler; I. N. Reid

1997-09-11

242

V838 Monocerotis revisited: Space phenomenon imitates art  

NASA Astrophysics Data System (ADS)

V838 Monocerotis revisited: Space phenomenon imitates art hi-res Size hi-res: 558 Kb Credits: NASA, the Hubble Heritage Team (AURA/STScI) and ESA V838 Monocerotis revisited: Space phenomenon imitates art "Starry Night", Vincent van Gogh's famous painting, is renowned for its bold whorls of light sweeping across a raging night sky. Although this image of the heavens came only from the artist's restless imagination, a new picture from the NASA/ESA Hubble Space Telescope bears remarkable similarities to the van Gogh work, complete with never-before-seen spirals of dust swirling across trillions of kilometres of interstellar space. This image, obtained with the Advanced Camera for Surveys on February 8, 2004, is Hubble's latest view of an expanding halo of light around a distant star, named V838 Monocerotis (V838 Mon). The illumination of interstellar dust comes from the red supergiant star at the middle of the image, which gave off a flashbulb-like pulse of light two years ago. V838 Mon is located about 20,000 light-years away from Earth in the direction of the constellation Monoceros, placing the star at the outer edge of our Milky Way galaxy V838 Monocerotis revisited: Space phenomenon imitates art hi-res Size hi-res: 1989 kb Credits: NASA, the Hubble Heritage Team (AURA/STScI) and ESA V838 Monocerotis revisited: Space phenomenon imitates art "Starry Night", Vincent van Gogh's famous painting, is renowned for its bold whorls of light sweeping across a raging night sky. Although this image of the heavens came only from the artist's restless imagination, a new picture from the NASA/ESA Hubble Space Telescope bears remarkable similarities to the van Gogh work, complete with never-before-seen spirals of dust swirling across trillions of kilometres of interstellar space. This image, obtained with the Advanced Camera for Surveys on February 8, 2004, is Hubble's latest view of an expanding halo of light around a distant star, named V838 Monocerotis (V838 Mon). The illumination of interstellar dust comes from the red supergiant star at the middle of the image, which gave off a flashbulb-like pulse of light two years ago. V838 Mon is located about 20,000 light-years away from Earth in the direction of the constellation Monoceros, placing the star at the outer edge of our Milky Way galaxy This image, obtained with the Advanced Camera for Surveys on 8 February 2004, is Hubble's latest view of an expanding halo of light around a distant star, named V838 Monocerotis (V838 Mon). The illumination of interstellar dust comes from the red supergiant star at the middle of the image, which gave off a flashbulb-like pulse of light two years ago. V838 Mon is located about 20 000 light-years away from Earth in the direction of the constellation Monoceros, placing the star at the outer edge of our Milky Way galaxy. Called a 'light echo', the expanding illumination of a dusty cloud around the star has been revealing remarkable structures ever since the star suddenly brightened for several weeks in early 2002. Though Hubble has followed the light echo in several snapshots, this new image shows swirls or eddies in the dusty cloud for the first time. These eddies are probably caused by turbulence in the dust and gas around the star as they slowly expand away. The dust and gas were likely ejected from the star in a previous explosion, similar to the 2002 event, which occurred some tens of thousands of years ago. The surrounding dust remained invisible and unsuspected until suddenly illuminated by the brilliant explosion of the central star two years ago. The Hubble Space Telescope has imaged V838 Mon and its light echo several times since the star's outburst in January 2002, in order to follow the constantly changing appearance of the dust as the pulse of illumination continues to expand away from the star at the speed of light. During the outburst event, the normally faint star suddenly brightened, becoming 600 000 times more luminous than our Sun. It was thus one of the most luminous stars in the entire Milky Way, until it faded

2004-03-01

243

Revisiting the Monoamine Hypothesis of Depression: A New Perspective  

PubMed Central

As the incidence of depression increases, depression continues to inflict additional suffering to individuals and societies and better therapies are needed. Based on magnetic resonance spectroscopy and laboratory findings, gamma aminobutyric acid (GABA) may be intimately involved in the pathophysiology of depression. The isoelectric point of GABA (pI = 7.3) closely approximates the pH of cerebral spinal fluid (CSF). This may not be a trivial observation as it may explain preliminary spectrophotometric, enzymatic, and HPLC data that monoamine oxidase (MAO) deaminates GABA. Although MAO is known to deaminate substrates such as catecholamines, indoleamines, and long chain aliphatic amines all of which contain a lipophilic moiety, there is very good evidence to predict that a low concentration of a very lipophilic microspecies of GABA is present when GABA pI = pH as in the CSF. Inhibiting deamination of this microspecies of GABA could explain the well-established successful treatment of refractory depression with MAO inhibitors (MAOI) when other antidepressants that target exclusively levels of monoamines fail. If further experimental work can confirm these preliminary findings, physicians may consider revisiting the use of MAOI for the treatment of non-intractable depression because the potential benefits of increasing GABA as well as the monoamines may outweigh the risks associated with MAOI therapy. PMID:24737931

Goldberg, Joel S; Bell, Clifton E; Pollard, David A

2014-01-01

244

Psychological Well-Being Revisited: Advances in Science and Practice  

PubMed Central

This article reviews the research and interventions that have grown up around a model of psychological well-being (Ryff, 1989) generated more than two decades ago to address neglected aspects of positive functioning, such as purposeful engagement in life, realization of personal talents and capacities, and enlightened self-knowledge. The conceptual origins of this formulation are revisited and scientific products emerging from six thematic areas are examined: (1) how well-being changes across adult development and later life, (2) what are the personality correlates of well-being, (3) how well-being is linked with experiences in family life, (4) how well-being relates to work and other community activities, (5) what are the connections between well-being and health, including biological risk factors, (6) and via clinical and intervention studies, how psychological well-being can be promoted for ever greater segments of society. Together, these topics illustrate flourishing interest across diverse scientific disciplines in understanding adults as striving, meaning-making, proactive organisms who are actively negotiating the challenges of life. A take-home message is that increasing evidence supports the health protective features of psychological well-being in reducing risk for disease and promoting length of life. A recurrent and increasingly important theme is resilience – the capacity to maintain or regain well-being in the face of adversity. Implications for future research and practice are considered. PMID:24281296

Ryff, Carol D.

2014-01-01

245

Advanced Single-Aisle Transport Propulsion Design Options Revisited  

NASA Technical Reports Server (NTRS)

Future propulsion options for advanced single-aisle transports have been investigated in a number of previous studies by the authors. These studies have examined the system level characteristics of aircraft incorporating ultra-high bypass ratio (UHB) turbofans (direct drive and geared) and open rotor engines. During the course of these prior studies, a number of potential refinements and enhancements to the analysis methodology and assumptions were identified. This paper revisits a previously conducted UHB turbofan fan pressure ratio trade study using updated analysis methodology and assumptions. The changes incorporated have decreased the optimum fan pressure ratio for minimum fuel consumption and reduced the engine design trade-offs between minimizing noise and minimizing fuel consumption. Nacelle drag and engine weight are found to be key drivers in determining the optimum fan pressure ratio from a fuel efficiency perspective. The revised noise analysis results in the study aircraft being 2 to 4 EPNdB (cumulative) quieter due to a variety of reasons explained in the paper. With equal core technology assumed, the geared engine architecture is found to be as good as or better than the direct drive architecture for most parameters investigated. However, the engine ultimately selected for a future advanced single-aisle aircraft will depend on factors beyond those considered here.

Guynn, Mark D.; Berton, Jeffrey J.; Tong, Michael T.; Haller, William J.

2013-01-01

246

Revisiting cancer immunoediting by understanding cancer immune complexity.  

PubMed

Since 1909, the cancer immunosurveillance concept has undergone four distinct eras. These include a general acceptance during 1957–1974, an abandonment during 1974–1996, resurrection during 1996–2001 in the form of an elegant theory of tumour immunoediting proposed by Robert Schreiber, and a retreat since 2006. Recently, in the Journal of Pathology, Ciampricotti et al reported an elegant experimental model designed by establishing RAG2?/?/MMTV-NeuT mice. Using this, they demonstrated that the development and metastasis of HER-2/neu-positive spontaneous mammary carcinoma were not altered by the presence or absence of the adaptive immune system. Their fascinating results are a call to revisit controversial reports as to an effective role of the adaptive immune system in tumour inhibition versus tumour promotion or tolerance in the development of spontaneous carcinomas. Ciampricotti and colleagues present a strong case for revising our ideas of cancer immunoediting and appreciating the complexity of the interaction between cancer and the immune system. PMID:21480229

Manjili, Masoud H

2011-05-01

247

NLTE in a Hot Hydrogen Star: Auer & Mihalas Revisited  

NASA Astrophysics Data System (ADS)

We pay tribute to two landmark papers published by Auer & Mihalas in 1969. They modeled hot-star NLTE-RE hydrogen-only atmospheres, using two simplified hydrogen atoms: ApJ 156, 157: H I levels 1, 2 and c, Lyman ? the only line ApJ 156, 681: H I levels 1, 2, 3 and c, Balmer ? the only line and computed LTE and NLTE models with the single line turned on and off. The results were extensively analyzed in the two papers. Any student of stellar line formation should take these beautiful papers to heart. The final exercise in Rutten's lecture notes ``Radiative Transfer in Stellar Atmospheres'' asks the student to work through five pages of questions concerning diagrams from the first paper alone! That exercise led to the present work in which we recompute the Auer-Mihalas hot-hydrogen-star models with TLUSTY, adding results from a complete hydrogen atom for comparison. Our motivation for this Auer-Mihalas re-visitation is twofold: 1. to add diagnostic diagrams to the ones published by Auer & Mihalas, in particular B?, J?, S? graphs to illustrate the role of the radiation field, and radiative heating & cooling graphs to illustrate the radiative energy budget, 2. to see the effect of adding the rest of the hydrogen atom.

Wiersma, J.; Rutten, R. J.; Lanz, T.

2003-01-01

248

Revisiting Directed Polymers with heavy-tailed disorder  

E-print Network

In this mostly numerical study, we revisit the statistical properties of the ground state of a directed polymer in a $d=1+1$ "hilly" disorder landscape, i.e. when the quenched disorder has power-law tails. When disorder is Gaussian, the polymer minimizes its total energy through a collective optimization, where the energy of each visited site only weakly contributes to the total. Conversely, a hilly landscape forces the polymer to distort and explore a larger portion of space to reach some particularly deep energy sites. As soon as the fifth moment of the disorder diverges, this mechanism radically changes the standard "KPZ" scaling behaviour of the directed polymer, and new exponents prevail. After confirming again that the Flory argument accurately predicts these exponent in the tail-dominated phase, we investigate several other statistical features of the ground state that shed light on this unusual transition and on the accuracy of the Flory argument. We underline the theoretical challenge posed by this situation, which paradoxically becomes even more acute above the upper critical dimension.

Thomas Gueudré; Pierre Le Doussal; Jean-Philippe Bouchaud; Alberto Rosso

2014-11-05

249

Interplant volatile signaling in willows: revisiting the original talking trees.  

PubMed

The importance of interplant volatile signaling in plant-herbivore interactions has been a contentious issue for the past 30 years. We revisit willows as the system in which evidence for interplant signaling was originally found, but then questioned. We established three well-replicated experiments with two willow species (Salix exigua and Salix lemmonii) to address whether the receipt of an interplant signal from a neighboring willow reduces herbivore damage. Additionally we tested whether this signal is volatile in nature, and whether plants signal better to themselves than they do to other individuals. In all three experiments, we found evidence that cues from a damaged neighbor reduce subsequent herbivory experienced by willows. In one experiment, we showed that bagging of clipped tissue, which prevents the exchange of volatile signals, removed the effect of neighbor wounding. This was consistent with results from the other two experiments, in which clipping potted neighbors connected only through airborne volatile cues reduced damage of receivers. In one year, we found evidence that the perception of volatile signals from genetically identical clones was more effective at reducing foliar damage to a neighbor than signals from a genetically different individual. However, this trend was not significant in the following year. In three well-replicated experiments, we found strong evidence for the importance of interplant volatile cues in mediating herbivore interactions with willows. PMID:23576105

Pearse, Ian S; Hughes, Kathy; Shiojiri, Kaori; Ishizaki, Satomi; Karban, Richard

2013-07-01

250

Rim curvature anomaly in thin conical sheets revisited  

E-print Network

This paper revisits one of the puzzling behaviors in a developable cone (d-cone), the shape obtained by pushing a thin sheet into a circular container of radius $ R $ by a distance $ \\eta $ [E. Cerda, S. Chaieb, F. Melo, and L. Mahadevan, {\\sl Nature} {\\bf 401}, 46 (1999)]. The mean curvature was reported to vanish at the rim where the d-cone is supported [T. Liang and T. A. Witten, {\\sl Phys. Rev. E} {\\bf 73}, 046604 (2006)]. We investigate the ratio of the two principal curvatures versus sheet thickness $h$ over a wider dynamic range than was used previously, holding $ R $ and $ \\eta $ fixed. Instead of tending towards 1 as suggested by previous work, the ratio scales as $(h/R)^{1/3}$. Thus the mean curvature does not vanish for very thin sheets as previously claimed. Moreover, we find that the normalized rim profile of radial curvature in a d-cone is identical to that in a "c-cone" which is made by pushing a regular cone into a circular container. In both c-cones and d-cones, the ratio of the principal curvatures at the rim scales as $ (R/h)^{5/2}F/(YR^{2}) $, where $ F $ is the pushing force and $ Y $ is the Young's modulus. Scaling arguments and analytical solutions confirm the numerical results.

Jin W. Wang

2011-12-01

251

Media Equation revisited. Do users show polite reactions towards an embodied agent?  

E-print Network

an impact on the on the evaluation of the ECA. Keywords: evaluation study, social effects, politeness, media equation 1 Introduction As by now is widely known the Computer as Social Actors research group (CASA- groupMedia Equation revisited. Do users show polite reactions towards an embodied agent? Laura Hoffmann1

Kopp, Stefan

252

Crystal Structure of A-amylose: a Revisit from Synchrotron Microdiffraction Analysis of Single Crystals  

E-print Network

1 Crystal Structure of A-amylose: a Revisit from Synchrotron Microdiffraction Analysis of Single;2 Abstract The three-dimensional structure of A-amylose crystals, as a model of the crystal domains of A-sized single crystals. The resulting datasets allowed a determination of the structure with conventional X

Paris-Sud XI, Université de

253

DIVERGENCE TIMES AND THE EVOLUTION OF EPIPHYTISM IN FILMY FERNS (HYMENOPHYLLACEAE) REVISITED  

E-print Network

DIVERGENCE TIMES AND THE EVOLUTION OF EPIPHYTISM IN FILMY FERNS (HYMENOPHYLLACEAE) REVISITED Sabine and Science, 4-1-1 Amakubo, Tsukuba 305-0005, Japan Although the phylogeny of the filmy fern family to examine the diversification of filmy ferns and the evolution of their ecology within a temporal context

Schuettpelz, Eric

254

L-H Transition Threshold; Orbit Loss Theory Revisited J.A. Heikkinen1  

E-print Network

L-H Transition Threshold; Orbit Loss Theory Revisited J.A. Heikkinen1 , T.P. Kiviniemi2 , T. Kurki is the ion orbit loss theory [2], where the ion orbit losses out of the plasma separatrix cause a loss. The theories vary in the way the radial electric field E is enhanced at transition. One of the oldest theories

255

Keyboard Acoustic Emanations Revisited Li Zhuang, Feng Zhou, J. D. Tygar  

E-print Network

Keyboard Acoustic Emanations Revisited Li Zhuang, Feng Zhou, J. D. Tygar University of California, Berkeley {zl,zf,tygar}@cs.berkeley.edu We examine the problem of keyboard acoustic emanations. We present on recovering keystrokes typed on a keyboard from a sound recording of the user typing. Emanations produced

Tygar, Doug

256

Keyboard Acoustic Emanations Revisited Li Zhuang, Feng Zhou, J. D. Tygar  

E-print Network

Keyboard Acoustic Emanations Revisited Li Zhuang, Feng Zhou, J. D. Tygar University of California, Berkeley {zl,zf,tygar}@cs.berkeley.edu ABSTRACT We examine the problem of keyboard acoustic emanations. We Terms: Security Keywords: Computer Security, Human Factors, Acoustic Emanations, Learning Theory, Hidden

Tygar, Doug

257

Observer-Controllers for Output Regulation: the Internal Model Principle Revisited  

E-print Network

Observer-Controllers for Output Regulation: the Internal Model Principle Revisited Jason H. Laks of the internal model principle that clarifies the necessary requirements for designing DAC-type observer-controllers Engineering, University of Colorado, Boulder, CO. Abstract This paper addresses the design of observer-controllers

Pao, Lucy Y.

258

The Best and the Rest: Revisiting the Norm of Normality of Individual Performance  

ERIC Educational Resources Information Center

We revisit a long-held assumption in human resource management, organizational behavior, and industrial and organizational psychology that individual performance follows a Gaussian (normal) distribution. We conducted 5 studies involving 198 samples including 633,263 researchers, entertainers, politicians, and amateur and professional athletes.…

O'Boyle, Ernest, Jr.; Aguinis, Herman

2012-01-01

259

Beliefs, attitude and behaviour towards fresh meat revisited after the Belgian dioxin crisis  

Microsoft Academic Search

This study revisits consumer beliefs, attitude and behaviour towards fresh meat consumption in Belgium after the occurrence of the dioxin crisis of 1999. The meat dioxin scare evoked a large amount of negative press, mainly pertained to poultry meat and pork. The focus of this follow-up study is on assessing shifts and persistence in consumer perception and attitude, based on

Wim Verbeke

2001-01-01

260

Some works of Furtwangler and Vandiver revisited and Fermat s last theorem  

E-print Network

Some works of Furtw¨angler and Vandiver revisited and Fermat s last theorem by Georges Gras cyclotomic approach to Fermat s last theorem for p > 3 and to a stronger version called SFLT, by introducing () with 1 (mod p2) (where c is the complex conjugation), then Fermat s last theorem holds for p. More

Paris-Sud XI, Université de

261

Revisiting First-Year College Students' Mattering: Social Support, Academic Stress, and the Mattering Experience  

ERIC Educational Resources Information Center

In this study, Nancy Schlossberg's (1989) theory of college students' mattering to others was revisited. Mattering is the experience of others depending on us, being interested in us, and being concerned with our fate. The relationships of gender, mattering to college friends and the college environment, and friend and family social support with…

Rayle, Andrea Dixon; Chung, Kuo-Yi

2008-01-01

262

Gale-Shapley Stable Marriage Problem Revisited: Strategic Issues and Applications  

E-print Network

Gale-Shapley Stable Marriage Problem Revisited: Strategic Issues and Applications (Extended studied by Gale and Shapley [2]. In a stable marriage problem we have two finite sets of players between the stable marriage model as described here, and the problem faced by the primary school students

Sethuraman, Jay

263

Extended Temporal Logic Revisited Orna Kupferman 1? Nir Piterman 2 Moshe Y. Vardi 3??  

E-print Network

Extended Temporal Logic Revisited Orna Kupferman 1? Nir Piterman 2 Moshe Y. Vardi 3?? 1 Hebrew://www.wisdom.weizmann.ac.il/ #24; nirp 3 Rice University, Department of Computer Science, Houston, TX 77251­1892, U.S.A. Email: vardi@cs.rice.edu, URL: http://www.cs.rice.edu/ #24; vardi Abstract. A key issue in the design

Vardi, Moshe Y.

264

G. van der Schrier J. Barkmeijer Bjerknes' hypothesis on the coldness during AD 17901820 revisited  

E-print Network

­1820 revisited Received: 1 July 2004 / Accepted: 16 November 2004 / Published online: 23 February 2005 � Springer that as much as 41­64% of pre-1850 Northern Hemisphere averaged temperature variations on decadal timescales in the winter season, lowering the sea-surface temperatures (SSTs) there with 0.3­1.0°C. This SST anomaly

Schrier, Gerard van der

265

Product differentiation when consumers may choose not to buy: Hotelling's convergence result revisited  

E-print Network

Product differentiation when consumers may choose not to buy: Hotelling's convergence result consumers may choose not to buy: Hotelling's convergence result revisited Karine Van der Straeten1 March Hotelling's spatial competition between two firms, but rather than assuming that consumers are ready to buy

Paris-Sud XI, Université de

266

Selection and Repetition, revisited CSC 1051 Villanova University Dr. Papalaskari 1  

E-print Network

Selection and Repetition, revisited CSC 1051 Villanova University Dr. Papalaskari 1 CSC 1051 ­ Data Course website: www.csc.villanova.edu/~map/1051/ Some slides in this presentation are adapted from the slides accompanying Java Software Solutions by Lewis & Loftus CSC 1051 M.A. Papalaskari, Villanova

Papalaskari, Mary-Angela

267

REVIEW Open Access Revisiting the B-cell compartment in mouse and  

E-print Network

characterised in the mouse; and the conventional, or lymph node type, B2 cells -- plus the detailed description by their expression of an immunoglobulin that serves the function of an antigen receptor, which mediates intracellular to be re-visited. As such, B-cells were found to express "Pathogen Recognition Receptors" such as TLRs

Boyer, Edmond

268

Revisiting the Use of LexicallyBased Features for Sentiment Detection Ben Allison  

E-print Network

Revisiting the Use of Lexically­Based Features for Sentiment Detection Ben Allison Department the problem of supervised sentiment detection using classifiers which are derived from word features. We argue that, while the literature has suggested the use of lexical features is inappropriate for sentiment

Edinburgh, University of

269

Revisiting Hele-Shaw Dynamics to Better Understand Beach O. Bokhove1,2  

E-print Network

Revisiting Hele-Shaw Dynamics to Better Understand Beach Evolution O. Bokhove1,2 , A.J. van der during storms, drives the evo- lution of beaches. Beach evolution by non-linear break- ing waves to the classic "Hele-Shaw" lab- oratory experiment can be designed that creates beach mor- phologies

Al Hanbali, Ahmad

270

Revisiting John Snow's map: network-based spatial demarcation of cholera area  

Microsoft Academic Search

Dr. John Snow's cholera map is known as one of the pioneering examples of an epidemiology map, illustrating the spatial distribution of the victims from the cholera outbreak. This article revisits his map and expands on his attempt at visualizing the distribution of the victims by focusing on spatial demarcation using the sphere of influence along the street network by

Shino Shiode

2012-01-01

271

Revisiting Numerical Pattern Mining with Formal Concept Analysis Mehdi Kaytoue1  

E-print Network

Revisiting Numerical Pattern Mining with Formal Concept Analysis Mehdi Kaytoue1 , Sergei O investigate the problem of mining numerical data with Formal Concept Analysis. The usual way is to use in climate analysis, etc. We introduce an original framework for mining numerical data based on advances

Paris-Sud XI, Université de

272

Globalisation, the Singapore Developmental State and Education Policy: A Thesis Revisited  

ERIC Educational Resources Information Center

In this article I revisit and extend arguments made in 1996 and 1997 about the relationship between globalisation, the state and education policy. I was particularly concerned then to see how a small but strong state, Singapore, was responding in the education arena to globalisation. I also wished to draw attention to the literature on the high…

Gopinathan, S.

2007-01-01

273

NOTES AND CORRESPONDENCE Stommel's Box Model of Thermohaline Circulation Revisited--The Role of Mechanical  

E-print Network

NOTES AND CORRESPONDENCE Stommel's Box Model of Thermohaline Circulation Revisited--The Role the wind-driven gyre. Stommel postulated a buoyancy constraint for the thermohaline circulation, and his basic idea has evolved into the dominating theory of thermohaline circulation; however, recently

Huang, Rui Xin

274

Phosphoric acid fractionation factors for calcite and aragonite between 25 and 75 C: Revisited  

E-print Network

Phosphoric acid fractionation factors for calcite and aragonite between 25 and 75 °C: Revisited-determine the phosphoric acid fractionation factor for calcite and aragonite in order to improve the accuracy and limit the uncertainty of this very important quantity. The 18 O/16 O ratio of 100% of the oxygen in calcite

Long, Bernard

275

Geochemistry of the Martian meteorite ALH 84001, revisited Jean-Alix BARRAT*  

E-print Network

Geochemistry of the Martian meteorite ALH 84001, revisited Jean-Alix BARRAT* and Claire BOLLINGER. INTRODUCTION In the absence of returned samples, the Martian meteorites provide a unique opportunity Martian meteorites have been identified. Most of them are shergottites or nakhlites. These rocks

Boyer, Edmond

276

Asian Lifelong Learning in the Context of a Global Knowledge Economy: A Task Re-Visited  

ERIC Educational Resources Information Center

This article revisits and reinterprets my previous paper. It is a snapshot of the lifelong learning system building in selected Asian countries, reflected in the mirror of the Asian Financial Crisis in the 1997s and the aftermath of that event. I reconsidered the arguments (1) the economic recession had delivered a global dimension of lifelong…

Han, Soonghee

2007-01-01

277

Revisiting "Grutter" and "Gratz" in the Wake of "Fisher": Looking Back to Move Forward  

ERIC Educational Resources Information Center

This article revisits the University of Michigan's 2003 affirmative action cases, "Grutter v. Bollinger" and "Gratz v. Bollinger." Through the aid of critical textual analysis and critical race theory, the author looks back at the predominant narratives that framed the challenge to, and defense of, race-conscious affirmative action policy in the…

Ledesma, Maria C.

2013-01-01

278

A Re-Visitation of Two Communities Represented in the Linguistic Atlas of New England.  

ERIC Educational Resources Information Center

A study was undertaken "to determine the extent and nature of change, if any, in the speech of two New England communities" since the fieldwork for the "Linguistic Atlas of New England" (LANE) was completed in 1932. Two rural communities, Granby and Deerfield, Massachusetts, were re-visited in order to interview the same three types of informants…

Carlson, David R.

279

Placing Search in Context: The Concept Revisited Lev Finkelstein, Evgeniy Gabrilovich  

E-print Network

Placing Search in Context: The Concept Revisited Lev Finkelstein, Evgeniy Gabrilovich , Yossi-based search engines are in widespread use today as a popular means for Web-based information retrieval to satisfy non-trivial information needs. This paper presents a new conceptual paradigm for performing search

Matias, Yossi

280

Placing Search in Context: The Concept Revisited Lev Finkelstein, Evgeniy Gabrilovich  

E-print Network

refinement questions or accumulated personalization information) [11]. Search engines have now enteredPlacing Search in Context: The Concept Revisited Lev Finkelstein, Evgeniy Gabrilovich 1 , Yossi describe a new paradigm for performing search in context. In the IntelliZap system we developed, search

Rivlin, Ehud

281

Spectral structure of laser light scattering revisited: bandwidths of nonresonant scattering lidars  

E-print Network

Spectral structure of laser light scattering revisited: bandwidths of nonresonant scattering lidars of the procedure of laser light scattering has led to a number of powerful lidar instruments for remote sensing in Rayleigh scattered light: a Doppler-broadened central peak, called the Cabannes line, and sidebands

282

Where Are They Now? LJ Revisits a Decade's Worth of Graduates  

ERIC Educational Resources Information Center

In this article, the author revisits 11 graduates who were profiled as part of LJ's annual Placements & Salaries issue. Armed with a library science degree from various institutions, they had just secured jobs in librarianship and were off to a good start forging their careers. Since then, they have worked at elementary school, college, and…

Kuzyk, Raya

2006-01-01

283

Cooling rates in the lower crust of the Oman ophiolite: Ca in olivine, revisited  

E-print Network

Cooling rates in the lower crust of the Oman ophiolite: Ca in olivine, revisited Jill A. Van crust of the Khafifah section in the Wadi Tayin massif of the Oman ophiolite. Additionally, very high B.V. All rights reserved. Keywords: calcium; olivine; oman; hydrothermal; cooling; crust 1

VanTongeren, Jill A.

284

Revisiting Interpretation of Canonical Correlation Analysis: A Tutorial and Demonstration of Canonical Commonality Analysis  

ERIC Educational Resources Information Center

In the face of multicollinearity, researchers face challenges interpreting canonical correlation analysis (CCA) results. Although standardized function and structure coefficients provide insight into the canonical variates produced, they fall short when researchers want to fully report canonical effects. This article revisits the interpretation of…

Nimon, Kim; Henson, Robin K.; Gates, Michael S.

2010-01-01

285

Nuggets of Mechanical Engineering - Revisit of the Free-Body Diagram Analysis and Force Flow Concept  

Microsoft Academic Search

Several key concepts in mechanical engineering, such as free-body diagram analysis, fo rce flow concept, stiffness network, observing coordina tes for kinematics, stress analysis, electric circuit analy sis, tolerancing, etc, often present great difficulties to students. In this paper, the author starts an atte mpt to revisit some fundamentals. It will be called nugge ts of mechanical engineering. Although no

Jay F. Tu

286

EPR before EPR: A 1930 Einstein-Bohr thought Experiment Revisited  

ERIC Educational Resources Information Center

In 1930, Einstein argued against the consistency of the time-energy uncertainty relation by discussing a thought experiment involving a measurement of the mass of the box which emitted a photon. Bohr seemingly prevailed over Einstein by arguing that Einstein's own general theory of relativity saves the consistency of quantum mechanics. We revisit…

Nikolic, Hrvoje

2012-01-01

287

Urban income inequality in China revisited (1988-2002)* Sylvie Dmurger  

E-print Network

1 Urban income inequality in China revisited (1988-2002)* Sylvie Démurger HIEBS, The University of Economics and Business, Beijing Normal University (China) This version: May 17, 2006 Abstract: Using newly the magnitude of inequality and inequality changes in China, as well as the role played by regional differences

Boyer, Edmond

288

Observa(onal Constraints on Brown Dwarf Forma(on Revisited  

E-print Network

Observa(onal Constraints on Brown Dwarf Forma(on Revisited Kevin Luhman (Penn State) #12;If a large frac(on of low-mass stars and brown dwarfs form (10x) IC348 Chamaeleon #12;Taurus Width of IMF and abundance of brown dwarfs

Joergens, Viki

289

Rare earth element partitioning between titanite and silicate melts: Henry's law revisited  

E-print Network

Rare earth element partitioning between titanite and silicate melts: Henry's law revisited Stefan earth elements (REE) between titanite and a range of different silicate melts. Our results show that Henry's law of trace element partitioning depends on bulk composition, the available partners

290

Literacy Interven-ons Revisited: Moving Up the Treatment Research Ladder  

E-print Network

Literacy Interven-ons Revisited: Moving Up the Treatment Research Ladder S C R O L L South Carolina Research on Language and Literacy h5p://sph.sc.edu/comd/scroll/ #12;S C R O L L South Carolina Research on Language and Literacy Introduc-on #12

Almor, Amit

291

Re-Visit to the School Nurse and Adolescents' Medicine Use  

ERIC Educational Resources Information Center

Objective: To examine if students who re-visit the school nurse use medicines differently than other students when exposed to aches and psychological problems. Methods: The study includes all 11-, 13- and 15-year-old students from a random sample of schools in Denmark, response rate 87 per cent, n = 5,205. The data collection followed the…

Borup, Ina K.; Andersen, Anette; Holstein, Bjorn E.

2011-01-01

292

Revisiting the Metaphor of the Island: Challenging "World Culture" from an Island Misunderstood  

ERIC Educational Resources Information Center

This article revisits the newly "discovered" island that world culture theorists have repeatedly utilised to explain their theoretical stance, conceptual preferences and methodological approach. Yet, it seeks to (re)connect world culture with the real world by replacing their imagined atoll with a real one--the island-nation of Japan. In…

Rappleye, Jeremy

2015-01-01

293

Critical Language Awareness in the United States: Revisiting Issues and Revising Pedagogies in a Resegregated Society  

ERIC Educational Resources Information Center

As scholars examine the successes and failures of more than 50 years of court-ordered desegregation since "Brown v. Board of Education of Topeka, Kansas," and 25 years of language education of Black youth since "Martin Luther King Elementary School Children v. Ann Arbor School District Board," this article revisits the key issues involved in those…

Alim, H. Samy

2005-01-01

294

OXYGEN GAS-PHASE ABUNDANCE REVISITED M. K. Andre,1,2  

E-print Network

OXYGEN GAS-PHASE ABUNDANCE REVISITED M. K. Andre´,1,2 C. M. Oliveira,2 J. C. Howk,2 R. Ferlet,1 J gas-phase oxygen abundance along the sight lines toward 19 early-type Galactic stars at an average mag�1 with a standard deviation of 15% is consistent with previous surveys. The mean oxygen abundance

Howk, Jay Christopher

295

Revisiting the codon adaptation index from a whole-genome perspective: analyzing the  

E-print Network

Revisiting the codon adaptation index from a whole-genome perspective: analyzing the relationship between gene expression and codon occurrence in yeast using a variety of models Ronald Jansen1 , Harmen J compositional bias, in terms of codon usage. Two widely used numerical indices, the codon adaptation index (CAI

Gerstein, Mark

296

REVISITING THE CODON ADAPTATION INDEX FROM A WHOLE-GENOME PERSPECTIVE  

E-print Network

REVISITING THE CODON ADAPTATION INDEX FROM A WHOLE-GENOME PERSPECTIVE: GENE EXPRESSION, CODON BIAS of nucleotides, called codons. The four nucleotides (A, T, C, G) define 64 codons used in the cell. Codons are not uniformly employed in the cell, but at the contrary, certain codons are preferred and we speak about codon

Carbone, Alessandra

297

Resampling methods revisited: advancing the understanding and applications in educational research  

Microsoft Academic Search

Resampling methods including randomization test, cross?validation, the jackknife and the bootstrap are widely employed in the research areas of natural science, engineering and medicine, but they lack appreciation in educational research. The purpose of the present review is to revisit and highlight the key principles and developments of resampling methods to advance the understanding and applications of resampling methods in

Haiyan Bai; Wei Pan

2008-01-01

298

REVISITING THE DEFINITION OF ANIMAL TOOL USE ST. AMANT & HORTON: ANIMAL TOOL USE  

E-print Network

, continue to advance our understanding of the behavioral and cognitive capabilities of animals today researchers in animal behavior. In this article, we analyze the criteria on which definitions of tool use1 REVISITING THE DEFINITION OF ANIMAL TOOL USE ST. AMANT & HORTON: ANIMAL TOOL USE ROBERT ST. AMANT

Young, R. Michael

299

THE BOY WHO CRIED WOLF REVISITED: THE IMPACT OF FALSE ALARM INTOLERANCE ON  

E-print Network

THE BOY WHO CRIED WOLF REVISITED: THE IMPACT OF FALSE ALARM INTOLERANCE ON COST-LOSS SCENARIOS M's fable about the "The Boy who Cried Wolf", a young shepherd boy guarding the village flock cries. This event is repeated two or three times before a wolf actually does show up on the hillside. The boy cries

Stevenson, Paul

300

Revisiting the rare earth elements in foraminiferal tests Brian A. Haley a,*, Gary P. Klinkhammer b  

E-print Network

Revisiting the rare earth elements in foraminiferal tests Brian A. Haley a,*, Gary P. Klinkhammer b of REEs in planktonic and benthic foraminifera. Several different cleaning protocols were tested. Although, it seems to remobilize metal oxides that are otherwise unaffected in flow-through dissolution

Kurapov, Alexander

301

Re-visiting the Foundations of Artificial Immune Systems for Data Mining  

E-print Network

Re-visiting the Foundations of Artificial Immune Systems for Data Mining Alex A. Freitas Jon Timmis) for data mining. By problem-oriented approach we mean that, in real-world data mining applications, the design of an AIS should take into account the characteristics of the data to be mined together

Timmis, Jon

302

Revisiting Backoff algorithms in CSMA/CA based MAC for channel Reservation in RFID reader  

E-print Network

Revisiting Backoff algorithms in CSMA/CA based MAC for channel Reservation in RFID reader Networks-scale dynamic RFID system with a number of readers deployed in order to maximize the system performance (i perform worse in a large-scale RFID dynamic system and require more additional components or are based

Paris-Sud XI, Université de

303

Public-Key Encryption Resilient Against Linear Related-Key Attacks Revisited  

E-print Network

Public-Key Encryption Resilient Against Linear Related-Key Attacks Revisited Hui Cui School as all the internal computations remain perfectly hidden. Unfortu- nately, this assumption does. In this case, the adversary might get some partial information about private keys through some methods, which

International Association for Cryptologic Research (IACR)

304

UTC-WP-08-02 Trip Generation Revisited: Estimation of Trip Generation Rates from  

E-print Network

WP-08-02 UTC-WP-08-02 Trip Generation Revisited: Estimation of Trip Generation Rates from Small-size sizes are large, estimates are generally not affected too much by a suspect observation. However misleading information) can play havoc with the quality of estimates and have a profound effect on forecasts

Illinois at Chicago, University of

305

Atmospheric Entry Heating of Micrometeorites Revisited: Higher Temperatures and Potential Biases  

NASA Technical Reports Server (NTRS)

The atmospheric entry heating model of Love and Brownlee appears to have overestimated evaporation rates by as much as two orders of magnitude. Here we revisit the issue of atmospheric entry heating, using a revised prescription for evaporation rates. Additional information is contained in the original extended abstract.

Love, S.; Alexander, C. M. OD.

2001-01-01

306

Revisiting the Age-Old Question: Does Money Matter in Education?  

ERIC Educational Resources Information Center

This policy brief revisits the long and storied literature on whether money matters in providing a quality education. Increasingly, political rhetoric adheres to the unfounded certainty that money doesn't make a difference in education, and that reduced funding is unlikely to harm educational quality. Such proclamations have even been used to…

Baker, Bruce D.

2012-01-01

307

Bearing capacity of spatially random soil: the undrained clay Prandtl problem revisited  

E-print Network

Bearing capacity of spatially random soil: the undrained clay Prandtl problem revisited D. V, an investigation has been performed into the bearing capacity of undrained clays with spatially vary- ing shear- tion of the soil's undrained shear strength impact on the statistics of the bearing capacity

308

The Gulf of Lion continental margin (NW Mediterranean) revisited by IBS: an overview  

E-print Network

The Gulf of Lion continental margin (NW Mediterranean) revisited by IBS: an overview MICHEL St study for stretching models of 'Atlantic-type' margins. However, when the Inte- grated Basin Study (IBS and the geodynamic setting of the margin within the Western Mediterranean. IBS-Gulf of Lion research was based

Demouchy, Sylvie

309

REVISITING THE "PERFECT DETECTOR" CONCEPT: electron moments from thermal noise spectroscopy and  

E-print Network

a large plasma volume. Thermal noise spectroscopy is based on a passive measurement of the plasma waveH if magnetised Principle: spectroscopy of plasma quasi-thermal noise measured at the ports of an electric antennaREVISITING THE "PERFECT DETECTOR" CONCEPT: electron moments from thermal noise spectroscopy

Meyer-Vernet, Nicole

310

Revisiting the anomalous rf field penetration into a warm plasma Igor D. Kaganovich  

E-print Network

transport the plasma current away from the skin layer due to their thermal motion. As a result, the widthRevisiting the anomalous rf field penetration into a warm plasma Igor D. Kaganovich Plasma Physics Radio frequency waves do not penetrate into a plasma and are damped within it. The elec- tric field

Kaganovich, Igor

311

Transformation of Learning in Education and Training: Key Qualifications Revisited. CEDEFOP Reference Series.  

ERIC Educational Resources Information Center

This book contains 15 papers examining European approaches to the theme of key qualifications. The following papers are included: "Key Qualifications Revisited: An Introduction" (Pekka Kamarainen); "Exploring Key Qualifications: Context, Theory, and Practice in Europe" (Pekka Kamarainen); "Rethinking Key Qualifications: Towards a New Framework"…

Kamarainen, Pekka, Ed.; Attwell, Graham, Ed.; Brown, Alan, Ed.

312

Revisiting the Steam-Boiler Case Study with LUTESS : Modeling for Automatic Test Generation  

E-print Network

Revisiting the Steam-Boiler Case Study with LUTESS : Modeling for Automatic Test Generation. In this paper, we apply this modeling principle to a well known case study, the steam boiler problem which has model and to assess the difficulty of such a process in a realistic case study. The steam boiler case

Boyer, Edmond

313

Shake-Your-Head: Revisiting Walking-In-Place for Desktop Virtual Reality Leo Terziman  

E-print Network

Shake-Your-Head: Revisiting Walking-In-Place for Desktop Virtual Reality L´eo Terziman INSA / INRIA it notably to the context of desktop Virtual Reality. With our novel "Shake-Your-Head" technique, the user.7 [Computer Graphics]: Three- Dimensional Graphics and Realism--Virtual Reality Keywords: Walking, Walking

Paris-Sud XI, Université de

314

Feeny revisited: condensed tannins as anti-herbivore defences in leaf-chewing herbivore communities of  

E-print Network

Feeny revisited: condensed tannins as anti-herbivore defences in leaf-chewing herbivore communities Sciences, George Washington University, Washington, U.S.A. Abstract. 1. Community level oak­tannin-chewing herbivores are negatively correlated with foliar condensed tannin concentrations and variation in condensed

Lill, John T.

315

Structural Analysis of fMRI Data Revisited: Improving the Sensitivity and Reliability of  

E-print Network

Structural Analysis of fMRI Data Revisited: Improving the Sensitivity and Reliability of fMRI Group Studies Abstract Group studies of functional MRI datasets are usually based on the computation of the mean coregistration of the individual datasets and normality of the measured signal at the group level, are frequently

Boyer, Edmond

316

Framing the Future: Revisiting the Place of Educational Expectations in Status Attainment  

ERIC Educational Resources Information Center

This study revisits the Wisconsin model of status attainment from a life course developmental perspective. Fixed-effects regression analyses lend strong support to the Wisconsin framework's core proposition that academic performance and significant others' influence shape educational expectations. However, investigating the process of expectation…

Bozick, Robert; Alexander, Karl; Entwisle, Doris; Dauber, Susan; Kerr, Kerri

2010-01-01

317

DAA-related APIs in TPM2.0 Revisited Trusted Computing and Information Assurance Laboratory  

E-print Network

DAA-related APIs in TPM2.0 Revisited Li Xi Trusted Computing and Information Assurance Laboratory is implemented by several APIs which can be utilized as a static Diffie- Hellman oracle. In this paper, we how to utilize these DAA-related APIs to break forward anonymity. Then we propose new APIs which

318

Phylogenetic relationships and heterogeneous evolutionary processes among phrynosomatine sand lizards (Squamata, Iguanidae) revisited  

E-print Network

lizards (Squamata, Iguanidae) revisited James A. Schulte II *, Kevin de Queiroz Division of Amphibians sand lizard rela- tionships. Sequences comprising 2871 aligned base pair positions representing the regions spanning ND1­COI and cyt b-tRNAThr of the mitochondrial genome from all recognized sand lizard

Schulte, Jim

319

Revisiting Jiang's dynamic continuum model for urban cities , S.C. Wong2  

E-print Network

Revisiting Jiang's dynamic continuum model for urban cities Jie Du1 , S.C. Wong2 , Chi-Wang Shu3 of travelers. The modeled region is a dense urban city, which is arbitrary in shape and has a single cen- tral, 2011, 45(2), 343-363) proposed a predictive continuum dynamic user-optimal (PDUO-C) model

Shu, Chi-Wang

320

The Frechet Distance Revisited and Extended # Sariel HarPeled + Benjamin Raichel #  

E-print Network

1 The Frâ??echet Distance Revisited and Extended # Sariel Har­Peled + Benjamin Raichel # March 8 show how to compute curves (in each complex) between these vertices, such that the Frâ??echet distance of weak Frâ??echet distance between curves. We also generalize the algorithm to handle an input of k

Har-Peled, Sariel

321

The Frechet Distance Revisited and Extended # Sariel HarPeled + Benjamin Raichel #  

E-print Network

1 The Frâ??echet Distance Revisited and Extended # Sariel Har­Peled + Benjamin Raichel # February 24 show how to compute curves (in each complex) between these vertices, such that the weak Frâ??echet notion of weak Frâ??echet distance between curves. We also generalize the algorithm to handle an input of k

Har-Peled, Sariel

322

The Peter Effect Revisited: Reading Habits and Attitudes of College Students  

ERIC Educational Resources Information Center

Certainly a primary goal of literacy education is the creation of avid, enthusiastic, and highly motivated readers. However, in this article revisiting the Peter Effect (Applegate & Applegate, 2004), researchers surveyed more than 1,000 college sophomores and found strikingly low levels of enthusiasm for reading. Only 46.6% of surveyed…

Applegate, Anthony J.; Applegate, Mary DeKonty; Mercantini, Martha A.; McGeehan, Catherine M.; Cobb, Jeanne B.; DeBoy, Joanne R.; Modla, Virginia B.; Lewinski, Kimberly E.

2014-01-01

323

Journal of Electrostatics 65 (2007) 296306 The lightning striking distance--Revisited  

E-print Network

of lightning protection to formulate the criterion for the onset of the upward connecting leader in termsJournal of Electrostatics 65 (2007) 296­306 The lightning striking distance--Revisited Vernon Cooraya,�, Vladimir Rakovb , Nelson Theethayia a Division for Electricity and Lightning Research, Uppsala

Florida, University of

324

Teacher Communication Concerns Revisited: Calling into Question the Gnawing Pull towards Equilibrium  

ERIC Educational Resources Information Center

This study revisits the long-standing teacher communication concerns framework originating over three decades ago. Analysis of 10 years of contemporary GTA teacher communication concerns reveals a typology of 10 concerns, which taken together construct teaching as a process of negotiating relationships, managing identities, and focusing attention.…

Dannels, Deanna P.

2015-01-01

325

Critical Language Awareness in the United States: Revisiting Issues and Revising Pedagogies in a Resegregated Society  

Microsoft Academic Search

As scholars examine the successes and failures of more than 50 years of court-ordered desegregation since Brown v. Board of Education of Topeka, Kansas, and 25 years of language education of Black youth since Martin Luther King Elementary School Children v. Ann Arbor School District Board, this article revisits the key issues involved in those cases and urges educators and

H. Samy Alim

2005-01-01

326

54 IEEE MICROWAVE AND GUIDED WAVE LETTERS, VOL. 9, NO. 2, FEBRUARY 1999 FDTD Dispersion Revisited  

E-print Network

54 IEEE MICROWAVE AND GUIDED WAVE LETTERS, VOL. 9, NO. 2, FEBRUARY 1999 FDTD Dispersion Revisited: Faster-Than-Light Propagation John B. Schneider, Member, IEEE, and Christopher L. Wagner Abstract--The numerical dispersion relation that governs the propagation of fields in a finite-difference time

Schneider, John B.

327

Streptophyte Algae and the Origin of Land Plants Revisited Using Heterogeneous Models with Three New Algal  

E-print Network

Letter Streptophyte Algae and the Origin of Land Plants Revisited Using Heterogeneous Models to understanding plant evolution. Previous studies have demonstrated that land plants evolved from streptophyte related to land plants. An early study based on four genes from three genomic compartments indicated

328

How people revisit web pages: empirical findings and implications for the design of history systems  

Microsoft Academic Search

We report on users' revisitation patterns to World Wide Web (web) pages, and use the results to lay an empirical foundation for the design of history mechanisms in web browsers. Through history, a user can return quickly to a previously visited page, possibly reducing the cognitive and physical overhead required to navigate to it from scratch. We analysed 6 weeks

Linda Tauscher; Saul Greenberg

1997-01-01

329

NeuroQuantology | March 2009 | Vol 7 | Issue 1 | Page 138-151 Glicksohn J. Time production and EEG alpha revisited  

E-print Network

Revisited Joseph Glicksohn* , Aviva Berkovich Ohana Tal Balaban Dotan , Abraham Goldstein , Opher Donchin posited, what Corresponding author: Joseph Glicksohn, Ph.D. Address:*Department of Criminology, Bar

Donchin, Opher

330

REVISITING ACCELERATION OF CHARGED GRAINS IN MAGNETOHYDRODYNAMIC TURBULENCE  

SciTech Connect

We study the acceleration of charged grains by magnetohydrodynamic (MHD) turbulence in the interstellar medium (ISM). We begin with revisiting gyroresonance acceleration by taking into account the fluctuations of grain guiding center along a uniform magnetic field (i.e., nonlinear theory-NLT). We calculate grain velocities due to gyroresonance by fast MHD modes using the NLT for different phases of the ISM and compare them with results obtained using quasi-linear theory (QLT). We find for the parameters applicable to the typical ISM phases that the fluctuations of the grain guiding center reduce grain velocities by less than 15%, but they can be important for more special circumstances. We confirm that large grains can be accelerated to super-Alfvenic velocities through gyroresonance. For such super-Alfvenic grains, we investigate the effect of further acceleration via transit-time damping (TTD) by fast modes. We find that due to the broadening of the resonance condition in the NLT, the TTD acceleration is not only important for the cosines of grain pitch angle relative to the magnetic field {mu} > V{sub A}/v, but also for {mu} < V{sub A}/v where v is the grain velocity and V{sub A} is the Alfven speed. We show that the TTD acceleration is dominant over the gyroresonance for large grains, and can increase substantially grain velocities induced by gyroresonance acceleration. We quantify another stochastic acceleration mechanism arising from low-frequency Alfven waves. We discuss the range of applicability of the mechanisms and their implications.

Hoang, Thiem; Lazarian, A. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Schlickeiser, R. [Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum, 44780 Bochum (Germany)

2012-03-01

331

Practical Considerations for Perforator Flap Thinning Procedures Revisited  

PubMed Central

Background A thin perforator flap is one of the best methods for covering defects. This study aimed to revisit and further test the rapidly advancing field of flap thinning techniques. Methods We performed two cadaveric studies to test the known flap thinning methods, and then applied these methods to a clinical series. In the first study, five cadavers were used to observe the anatomical relation of the perforator with the subdermal plexuses and the subcutaneous fat layer by injecting a colored latex solution. The second study was done on four cadavers independently from the first study. Last, a clinical series was performed on 15 patients. Results The areolar fat lobules of 10 anterolateral thigh perforator (ALT), seven deep inferior epigastric artery perforator (DIEAP), and six thoracodorsal artery perforator (TAP) flaps were dissected to reduce the flap thickness guided by the colored vascular pattern. On average, the ALT, DIEAP, and TAP flaps were reduced to 32.76%±9.76%, 37.01%±9.21%, and 35.42%±9.41%, respectively. In the second study, the areolar fat lobules were directly dissected in six ALT, six TAP, and four MSAP flaps, and an average reduction in flap thickness of 53.41%±5.64%, 52.30%±2.88%, and 47.87%±6.41%, respectively, was found. In the clinical series, 13 out of the 15 cases yielded satisfactory outcomes with an average thickness reduction of 37.91%±7.15%. Conclusions These multiple studies showed that the deep fat layer could be safely removed to obtain a thin yet viable perforator flap. This evidence suggests that the macroscopic flap thinning technique can achieve thin flaps. Surgeons should consider this technique before embracing the latest technique of supermicrosurgery. PMID:25396182

Bangun, Kristaninta; Buchari, Frank B; Rezkini, Putri

2014-01-01

332

Antisolar differential rotation of the K1-giant ? Geminorum revisited  

NASA Astrophysics Data System (ADS)

Context. Surface differential rotation and other global surface flows on magnetically active stars are among the observable manifestations of the underlying stellar dynamo. Therefore, these types of observations are important for stellar dynamo theory and useful constraints for solar dynamo studies as well. Aims: We revisit the active K1-giant component of the long-period RS CVn-type binary system ? Gem and its global surface flow pattern. Methods: We refine the differential rotation law from recovering the spot migration pattern. We apply a detailed cross-correlation technique to a unique set of 34 time-series Doppler images recovered using data from 1996-97. By increasing the number of the available cross-correlation function maps, we expect a more robust determination of the differential surface rotation law. In addition, we present a new time-series Doppler imaging study of ? Gem using our advanced surface reconstruction code iMap for a data set collected in 2006-07. Results: Results from the reprocessed cross-correlation study confirm that the star performs antisolar-type differential rotation with a surface shear ? of - 0.04 ± 0.01, i.e., almost a factor of two larger compared to the previously claimed value. We also confirm the evidence of a global poleward spot migration, with an average velocity of 0.21 ± 0.03 km s-1, in accordance with theoretical predictions. From the new observations, we obtain three subsequent Doppler images. The time evolution of these images confirms the antisolar-type differential rotation of the same amount.

K?vári, Zs.; Kriskovics, L.; Künstler, A.; Carroll, T. A.; Strassmeier, K. G.; Vida, K.; Oláh, K.; Bartus, J.; Weber, M.

2015-01-01

333

Coarse woody debris dynamics: revisiting a boreal black spruce chronosequence  

NASA Astrophysics Data System (ADS)

We re-visited a seven-stand boreal chronosequence west of Thompson, Manitoba, Canada, in which coarse woody debris (CWD) and its instantaneous decomposition were measured in 2000. New CWD levels and tree and snag fall rates were measured in 2007, and the resulting data used to evaluate how well CWD changes can be modeled using one- and three-pool decay class models. Thus this study compared three independent measures of decomposition (k): direct measurements of CWD respiration; rates based on a seven-year resampling effort; and rates inferred from the chronosequence progression itself. Measured CWD was between 3.3 and 80.4 Mg ha-1, with the lowest and highest values in the 77- and 18-year-old stands, respectively. Spatial variability was high, and thus at most stands CWD levels had not changed significantly from 2000 to 2007. Snag fall rate varied by an order of magnitude, from 1.4% yr-1 in the 43-year-old stand to 10.4% yr-1 in the 12-year-old stand. A one-pool model based on these inputs underestimated actual 2000-2007 CWD decomposition, implying that fragmentation was at least as important a process as heterotrophic respiration; the mean overall k was 0.08 for most stands. The three-pool model was hampered by limited data on decay class transition rates and performed no better than the one-pool model. Although the computed k values implied a failure in chronosequence site selection for at least one site, the overall CWD trend was consistent with a larger number of sites surveyed in the region.

Bond-Lamberty, B.; Gower, S. T.

2007-12-01

334

Revisiting the Interpretation of Thorium Abundances at Hansteen Alpha  

NASA Technical Reports Server (NTRS)

Hansteen Alpha is one of the few remaining locations on the Moon thought to be formed by highlands volcanism. Hansteen Alpha is a triangular shaped feature located in the southern portion of Oceanus Procellarum (12 degrees W, 50 degrees S) and its size is approximately 25 km on each side. As described by Hawke et al., there is clear evidence that: 1) Hansteen Alpha was emplaced by extrusive volcanic processes; and 2) it was formed by a viscous lava that should be enriched in Th. However, in the study of Hawke et al. using available Lunar Prospector (LP) Th data, it was concluded that the Hansteen Alpha region was not greatly enriched in Th as would be expected for a highly evolved, viscous lava. It was further concluded based on other compositional data that the magma that formed Hansteen Alpha did not correspond to any known rock type. Here we revisit the interpretation of Th abundances at Hansteen Alpha for a couple of reasons. First, the size of Hansteen Alpha is smaller than the spatial resolution of the LP Gamma-ray Spectrometer (LP-GRS) from which the Th abundances were derived. Therefore, the LP-GRS pixels covering Hansteen Alpha may not truly represent the Th abundance of the Hansteen Alpha feature. Second, recent work has led to a much greater understanding of the Th spatial distribution for small-area features on the lunar surface. In particular, using forward modeling techniques, we have developed the ability to obtain information about Th abundances for features that are at or smaller than the FWHM spatial resolution (approximately [80 square kilometers]) of the LP-GRS data.

Lawrence, D. J.; Hawke, B. R.; Elphic, R. C.; Feldman, W. C.; Prettyman, T. H.; Vaniman, D. T.

2004-01-01

335

Revisiting four scientific debates in ocean acidification research  

NASA Astrophysics Data System (ADS)

In recent years, ocean acidification has gained continuously increasing attention from scientists and a number of stakeholders and has raised serious concerns about its effects on marine organisms and ecosystems. With the increase in interest, funding resources, and the number of scientific investigations focusing on this environmental problem, increasing amounts of data and results have been produced, and a progressively growing and more rigorous understanding of this problem has begun to develop. Nevertheless, there are still a number of scientific debates, and in some cases misconceptions, that keep reoccurring at a number of forums in various contexts. In this article, we revisit four of these topics that we think require further thoughtful consideration including: (1) surface seawater CO2 chemistry in shallow water coastal areas, (2) experimental manipulation of marine systems using CO2 gas or by acid addition, (3) net versus gross calcification and dissolution, and (4) CaCO3 mineral dissolution and seawater buffering. As a summation of these topics, we emphasize that: (1) many coastal environments experience seawater pCO2 that is significantly higher than expected from equilibrium with the atmosphere and is strongly linked to biological processes; (2) addition of acid, base or CO2 gas to seawater can all be useful techniques to manipulate seawater chemistry in ocean acidification experiments; (3) estimates of calcification or CaCO3 dissolution based on present techniques are measuring the net of gross calcification and dissolution; and (4) dissolution of metastable carbonate mineral phases will not produce sufficient alkalinity to buffer the pH and carbonate saturation state of shallow water environments on timescales of decades to hundreds of years to the extent that any potential negative effects on marine calcifiers will be avoided.

Andersson, A. J.; MacKenzie, F. T.

2012-03-01

336

PHOTOEVAPORATION OF CIRCUMSTELLAR DISKS REVISITED: THE DUST-FREE CASE  

SciTech Connect

Photoevaporation by stellar ionizing radiation is believed to play an important role in the dispersal of disks around young stars. The mass-loss model for dust-free disks developed by Hollenbach et al. is currently regarded as the conventional one and has been used in a wide variety of studies. However, the rate in this model was derived using the crude so-called 1+1D approximation of ionizing radiation transfer, which assumes that diffuse radiation propagates in a direction vertical to the disk. In this study, we revisit the photoevaporation of dust-free disks by solving the two-dimensional axisymmetric radiative transfer for steady-state disks. Unlike that solved by the conventional model, we determine that direct stellar radiation is more important than the diffuse field at the disk surface. The radial density distribution at the ionization boundary is represented by a single power law with index -3/2 in contrast to the conventional double power law. For this distribution, the photoevaporation rate from the entire disk can be written as a function of the ionizing photon emissivity {Phi}{sub EUV} from the central star and the disk outer radius r{sub d} as follows: M-dot{sub PE} = 5.4 x 10{sup -5} ({Phi}{sub EUV}/10{sup 49} s{sup -1}){sup 1/2} (r{sub d}/1000 AU){sup 1/2} M{sub Sun} yr{sup -1}. This new rate depends on the outer disk radius rather than on the gravitational radius as in the conventional model, because of the enhanced contribution to the mass loss from the outer disk annuli. In addition, we discuss its applications to present-day as well as primordial star formation.

Tanaka, Kei E. I.; Omukai, Kazuyuki [Astronomical Institute, Tohoku University, Sendai 980-8578 (Japan); Nakamoto, Taishi, E-mail: ktanaka@astr.tohoku.ac.jp [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo 152-8551 (Japan)

2013-08-20

337

Stern, C.D. (1991) Mesoderm formation in the chick embryo, revisited. In: Gastrulation: movements, patterns and molecules (ed. R. Keller, W.H. Clark Jr and F. Griffin). New York  

E-print Network

Stern, C.D. (1991) Mesoderm formation in the chick embryo, revisited. In: Gastrulation: movements;Stern, C.D. (1991) Mesoderm formation in the chick embryo, revisited. In: Gastrulation: movements;Stern, C.D. (1991) Mesoderm formation in the chick embryo, revisited. In: Gastrulation: movements

Stern, Claudio

338

The Angular Momentum of Baryons and Dark Matter Halos Revisited  

NASA Technical Reports Server (NTRS)

Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive-mesh refinement (AMR), we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r = 0.1R(sub vir). In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/R(sub vir) > 0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its virialised dark matter halo host. This generic result holds for halos of all masses at all redshifts, as radiative cooling ensures that a significant fraction of baryons remain trapped at the centre of the halos. Despite this injection of angular momentum enriched gas, we predict an amount for stellar discs which is in fair agreement with observations at z=0. This arises because the total specific angular momentum of the baryons (gas and stars) remains close to that of dark matter halos. Indeed, our simulations indicate that any differential loss of angular momentum amplitude between the two components is minor even though dark matter halos continuously lose between half and two-thirds of their specific angular momentum modulus as they evolve. In light of our results, a substantial revision of the standard theory of disc formation seems to be required. We propose a new scenario where gas efficiently carries the angular momentum generated by large-scale structure motions deep inside dark matter halos, redistributing it only in the vicinity of the disc.

Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

2011-01-01

339

Sexual negotiation in the AIDS era: negotiated safety revisited.  

PubMed

Data from the Sydney Men and Sexual Health study were used to revisit negotiated safety. Recruitment for the study took place between November 1992 and February 1995 and involved 1037 homosexual men who were interviewed using a questionnaire. The focus was on 354 men who had been in a regular relationship for 6 months or more. Over 52% were engaged in professional occupations and their age ranged from 17 to 69 years. 181 men of the 354 reported being in a seronegative concordant regular relationship. 61.9% of these 181 had engaged in unprotected anal intercourse at least once, while 91% (165 men) had not engaged in unprotected sex outside their relationship. Of these 39.2% either had not engaged in sex outside their relationship at least in the 6 months prior to the interview, or they had not engaged in anal intercourse (34.9%), or they had engaged only in protected anal intercourse (27.1%). 82% (135) of those who had not engaged in unprotected anal intercourse outside their regular relationship had entered into an agreement with their partner, whereas only 56% (9) of those who had engaged in unprotected anal intercourse had an agreement. What distinguished the 165 men who did not engage in unprotected anal intercourse with a casual partner from the 16 men who did was also examined. Men who lived in gay areas of Sidney were more likely to engage in unprotected anal intercourse with casual partners than those who lived elsewhere (p = 0.06). Having a safety agreement was predictive of safer sex when compared with no agreement at all. The best agreement with regard to safe sex with casual partners was no anal sex. 74 (44.8%) of the 165 men who thought that anal intercourse was not important had not engaged in unprotected sex. Men who found condom use acceptable were more likely to avoid unprotected anal intercourse with their casual partners. The strategy of negotiated safety among men in HIV-seronegative regular relationships may promote safe sex. PMID:9030366

Kippax, S; Noble, J; Prestage, G; Crawford, J M; Campbell, D; Baxter, D; Cooper, D

1997-02-01

340

Revisited Inventory of Glaciers on Axel Heiberg Island, Nunavut  

NASA Astrophysics Data System (ADS)

As documented in the IPCC's Climate Change 2007 report, the high latitude regions of the Northern Hemisphere are experiencing the highest rates of warming. Given that 35% of the global glacial ice exists within the Arctic Archipelago, this region provides an excellent laboratory for monitoring the anticipated degree of glacial recession [1]. Evidence of arctic warming through negative mass balance trends has been detected in several studies already [e.g., 2]. Here, we show the importance and value of historical records in the task of monitoring glacial retreat. A highly detailed inventory developed by S. Ommanney in 1969 [3], has been revisited and transformed into digital format for the purposes of integration with modern inventories. The Ommanney inventory covers the entirety of Axel Heiberg Island , NU, and includes details often lacking in present day inventories, including orientations (accumulation and ablation zones), elevations (highest, lowest, elevation of the snowline, and the mean elevations of both the accumulation and ablation areas), length (of the ablation area, exposed ice, and of the total glacier including debris cover), area (of the ablation area, exposed ice, and of the total glacier), accumulation area ratio (AAR), depth, volume, and a six digit code which gives qualitative details on glacier attributes. This report is one of the most thorough and comprehensive glacier inventory report ever published in Canada. More recent inventories used for comparison include the glacier extents created by the National Topographic System based on photography from 1980-1987, as well as extents developed by Dr. Luke Copland for the Global Land Ice Measurements from Space (GLIMS) database using 1999-2000 satellite imagery. Our preliminary results show that approximately 90% of ice bodies under 0.2km on Axel Heiberg Island have disappeared entirely in the 40 year period of interest. The issue of glacier definition will be discussed as a possible cause of these drastic changes in the status of small, remnant glaciers. Recession trends will also be discussed with respect to glacier characteristics and regional distribution. [1] Barry, R. G., Progress in Physical Geography, 2006. 30(3): p. 285-306; [2] Dowdeswell, J. A., et al., Quaternary Research, 1997. 40: p. 1-14; [3] Ommanney, C. S. L., McGill Subarctic Research Paper, 1969. 40: p. 5-67.

Thomson, L.; Osinski, G.

2009-05-01

341

Revisiting Scaling Relations for Giant Radio Halos in Galaxy Clusters  

NASA Technical Reports Server (NTRS)

Many galaxy clusters host megaparsec-scale radio halos, generated by ultrarelativistic electrons in the magnetized intracluster medium. Correlations between the synchrotron power of radio halos and the thermal properties of the hosting clusters were established in the last decade, including the connection between the presence of a halo and cluster mergers. The X-ray luminosity and redshift-limited Extended GMRT Radio Halo Survey provides a rich and unique dataset for statistical studies of the halos. We uniformly analyze the radio and X-ray data for the GMRT cluster sample, and use the new Planck Sunyaev-Zel'dovich (SZ) catalog to revisit the correlations between the power of radio halos and the thermal properties of galaxy clusters. We find that the radio power at 1.4 GHz scales with the cluster X-ray (0.1-2.4 keV) luminosity computed within R(sub 500) as P(sub 1.4) approx. L(2.1+/-0.2) - 500). Our bigger and more homogenous sample confirms that the X-ray luminous (L(sub 500) > 5 × 10(exp 44) erg/s)) clusters branch into two populations-radio halos lie on the correlation, while clusters without radio halos have their radio upper limits well below that correlation. This bimodality remains if we excise cool cores from the X-ray luminosities. We also find that P(sub 1.4) scales with the cluster integrated SZ signal within R(sub 500), measured by Planck, as P(sub 1.4) approx. Y(2.05+/-0.28) - 500), in line with previous findings. However, contrary to previous studies that were limited by incompleteness and small sample size, we find that "SZ-luminous" Y(sub 500) > 6×10(exp -5) Mpc(exp 2) clusters show a bimodal behavior for the presence of radio halos, similar to that in the radio-X-ray diagram. Bimodality of both correlations can be traced to clusters dynamics, with radio halos found exclusively in merging clusters. These results confirm the key role of mergers for the origin of giant radio halos, suggesting that they trigger the relativistic particle acceleration.

Cassano, R.; Ettori, S.; Brunetti, G.; Giacintucci, S.; Pratt, G. W.; Venturi, T.; Kale, R.; Dolag, K.; Markevitch, Maxim L.

2013-01-01

342

7/1/09 7:49 PMSage Worksheet: Archimedes Revisited Page 1 of 3http://localhost:8000/home/admin/80/print  

E-print Network

7/1/09 7:49 PMSage Worksheet: Archimedes Revisited Page 1 of 3http://localhost:8000/home/admin/80/print Archimedes Revisited What Archimedes didn't know about What Archimedes did know about Archimedes computations when trying to approximate Ã?! However, Archimedes computed these values using nothing more than

Landweber, Gregory D.

343

Revisiting the Absolutely Minimal Realization for Two-dimensional Digital Filters  

Microsoft Academic Search

The open problem of absolutely minimal state-space realization for two-dimensional (2D) digital filters is revisited. A thorough investigation is carried out for the class of first order 2D digital filters. It is found that the canonical form proposed by Kung et al. three decades ago is incomplete, probably due to an incorrect assumption, which is also pointed out for the

Zhiping Lin; Li Xu; Yoshihisa Anazawa

2007-01-01

344

Why is it so difficult to compare treebanks? TIGER and TuBa-D/Z revisited  

E-print Network

Why is it so difficult to compare treebanks? TIGER and T¨uBa-D/Z revisited Ines Rehbein and Josef a thorough comparison of two German treebanks: the TIGER treebank and the T¨uBa-D/Z. We use simple statistics evaluation of a set of 100 sentences from the T¨uBa- D/Z, manually annotated in the TIGER as well as in the T

van Genabith, Josef

345

Freud’s civilization revisited in the nuclear age: commentary on O’Brien’s conclusions  

Microsoft Academic Search

This comment is a constructive criticism of Professor John C. O’Brien’s interesting and provocative article: “Freud’s civilization revisited in the nuclear age.” It is my conviction that both Freud and O’Brien underestimate the power of Christianity in the creation and in the defense of Western civilization. The threat of a nuclear holocaust is an ever present danger, but the remedy

Lewis E. Hill

2001-01-01

346

Differential-algebraic and bi-Hamiltonian integrability analysis of the Riemann hierarchy revisited  

NASA Astrophysics Data System (ADS)

A differential-algebraic approach to studying the Lax integrability of the generalized Riemann type hydrodynamic hierarchy is revisited and its new Lax representation is constructed in exact form. The bi-Hamiltonian integrability of the generalized Riemann type hierarchy is discussed by means of the gradient-holonomic and symplectic methods and the related compatible Poissonian structures for N = 3 and N = 4 are constructed.

Prykarpatsky, Yarema A.; Artemovych, Orest D.; Pavlov, Maxim V.; Prykarpatsky, Anatoliy K.

2012-10-01

347

Stability of Schwarzschild black holes in fourth-order gravity revisited  

E-print Network

We revisit the classical stability of Schwarzschild black hole in fourth-order theories of gravity. On the contrary of the stability of this black hole, it turns out that the linearized perturbations exhibit unstable modes featuring the Gregory-Laflamme instability of five-dimensional black string. This shows clearly an instability of black hole in fourth-order gravity with $\\alpha=-\\beta/3$.

Yun Soo Myung

2013-07-15

348

Kidney-specific chromosome transfer in genetic hypertension: The Dahl hypothesis revisited  

Microsoft Academic Search

Kidney-specific chromosome transfer in genetic hypertension: The Dahl hypothesis revisited.BackgroundA central dogma in the field of essential hypertension research is that the genetic transmission of increased blood pressure is determined solely by the genotype of the kidney. This concept is based in large part on studies in experimental rat models of spontaneous hypertension in which transplantation of a kidney from

Paul C Churchill; Monique C Churchill; Anil K Bidani; Theodore W Kurtz

2001-01-01

349

Thermodynamic approach to field equations in Lovelock gravity and f(R) gravity revisited  

NASA Astrophysics Data System (ADS)

The first law of thermodynamics at black hole horizons is known to be obtainable from the gravitational field equations. A recent study claims that the contributions at inner horizons should be considered in order to give the conventional first law of black hole thermodynamics. Following this method, we revisit the thermodynamic aspects of field equations in the Lovelock gravity and f(R) gravity by focusing on two typical classes of charged black holes in the two theories.

Miao, Yan-Gang; Yuan, Fang-Fang; Zhang, Zheng-Zheng

2014-10-01

350

The 90° problem of scattering theory revisited: dynamical turbulence versus nonlinear effects  

Microsoft Academic Search

The 90° problem of cosmic-ray transport theory is revisited in this paper. By using standard forms of the wave spectrum in the solar wind, the pitch-angle Fokker-Planck coefficient and the parallel mean free path are computed for different resonance functions. A critical comparison is made of the strength of 90° scattering due to plasmawave effects, dynamical turbulence effects and nonlinear

A. Dosch; I. Kourakis; A. Shalchi

2007-01-01

351

Taï chimpanzees anticipate revisiting high-valued fruit trees from further distances.  

PubMed

The use of spatio-temporal memory has been argued to increase food-finding efficiency in rainforest primates. However, the exact content of this memory is poorly known to date. This study investigated what specific information from previous feeding visits chimpanzees (Pan troglodytes verus), in Taï National Park, Côte d'Ivoire, take into account when they revisit the same feeding trees. By following five adult females for many consecutive days, we tested from what distance the females directed their travels towards previously visited feeding trees and how previous feeding experiences and fruit tree properties influenced this distance. To exclude the influence of sensory cues, the females' approach distance was measured from their last significant change in travel direction until the moment they entered the tree's maximum detection field. We found that chimpanzees travelled longer distances to trees at which they had previously made food grunts and had rejected fewer fruits compared to other trees. In addition, the results suggest that the chimpanzees were able to anticipate the amount of fruit that they would find in the trees. Overall, our findings are consistent with the hypothesis that chimpanzees act upon a retrieved memory of their last feeding experiences long before they revisit feeding trees, which would indicate a daily use of long-term prospective memory. Further, the results are consistent with the possibility that positive emotional experiences help to trigger prospective memory retrieval in forest areas that are further away and have fewer cues associated with revisited feeding trees. PMID:24950721

Ban, Simone D; Boesch, Christophe; Janmaat, Karline R L

2014-11-01

352

Associations between in-hospital bed occupancy and unplanned 72-h revisits to the emergency department: a register study  

PubMed Central

Background A possible downstream effect of high in-hospital bed occupancy is that patients in the emergency department (ED) who would benefit from in-hospital care are denied admission. The present study aimed at evaluating this hypothesis through investigating associations between in-hospital bed occupancy at the time of presentation in the ED and the probability for unplanned 72-hour (72-h) revisits to the ED among patients discharged at index. A second outcome was unplanned 72-h revisits resulting in admission. Methods All visits to the ED of a 420-bed emergency hospital in southern Sweden between 1 January 2011 and 31 December 2012, which did not result in admission, death, or transfer to another hospital were included. Revisiting fractions were computed for in-hospital occupancy intervals <85%, 85% to 90%, 90% to 95%, 95% to 100%, 100% to 105%, and ?105%. Multivariate models were constructed in an attempt to take confounding factors from, e.g., presenting complaints, age, referral status, and triage priority into account. Results Included in the study are 81,878 visits. The fraction of unplanned 72-h revisits/unplanned 72-h revisits resulting in admission was 5.8%/1.4% overall, 6.2%/1.4% for occupancy <85%, 6.4%/1.5% for occupancy 85% to 90%, 5.8%/1.4% for occupancy 90% to 95%, 6.0%/1.6% for occupancy 95% to 100%, 5.4%/1.6% for occupancy 100% to 105%, and 4.9%/1.4% for occupancy ?105%. In the multivariate models, a trend to lower probability of unplanned 72-h revisits was observed at occupancy ?105% compared to occupancy <95% (OR 0.88, CI 0.76 to 1.01). No significant associations between in-hospital occupancy at index and the probability of making unplanned 72-h revisits resulting in admission were observed. Conclusions The lack of associations between in-hospital occupancy and unplanned 72-h revisits does not support the hypothesis that ED patients are inappropriately discharged when in-hospital beds are scarce. The results are reassuring as they indicate that physicians are able to make good decisions, also while resources are constrained. PMID:25045408

2014-01-01

353

Risk Prediction of Emergency Department Revisit 30 Days Post Discharge: A Prospective Study  

PubMed Central

Background Among patients who are discharged from the Emergency Department (ED), about 3% return within 30 days. Revisits can be related to the nature of the disease, medical errors, and/or inadequate diagnoses and treatment during their initial ED visit. Identification of high-risk patient population can help device new strategies for improved ED care with reduced ED utilization. Methods and Findings A decision tree based model with discriminant Electronic Medical Record (EMR) features was developed and validated, estimating patient ED 30 day revisit risk. A retrospective cohort of 293,461 ED encounters from HealthInfoNet (HIN), Maine's Health Information Exchange (HIE), between January 1, 2012 and December 31, 2012, was assembled with the associated patients' demographic information and one-year clinical histories before the discharge date as the inputs. To validate, a prospective cohort of 193,886 encounters between January 1, 2013 and June 30, 2013 was constructed. The c-statistics for the retrospective and prospective predictions were 0.710 and 0.704 respectively. Clinical resource utilization, including ED use, was analyzed as a function of the ED risk score. Cluster analysis of high-risk patients identified discrete sub-populations with distinctive demographic, clinical and resource utilization patterns. Conclusions Our ED 30-day revisit model was prospectively validated on the Maine State HIN secure statewide data system. Future integration of our ED predictive analytics into the ED care work flow may lead to increased opportunities for targeted care intervention to reduce ED resource burden and overall healthcare expense, and improve outcomes. PMID:25393305

Hao, Shiying; Jin, Bo; Shin, Andrew Young; Zhao, Yifan; Zhu, Chunqing; Li, Zhen; Hu, Zhongkai; Fu, Changlin; Ji, Jun; Wang, Yong; Zhao, Yingzhen; Dai, Dorothy; Culver, Devore S.; Alfreds, Shaun T.; Rogow, Todd; Stearns, Frank; Sylvester, Karl G.; Widen, Eric; Ling, Xuefeng B.

2014-01-01

354

Plasmodium vivax malaria elimination: should innovative ideas from the past be revisited?  

PubMed Central

In the 1950s, the strategy of adding chloroquine to food salt as a prophylaxis against malaria was considered to be a successful tool. However, with the development of Plasmodium resistance in the Brazilian Amazon, this control strategy was abandoned. More than 50 years later, asexual stage resistance can be avoided by screening for antimalarial drugs that have a selective action against gametocytes, thus old prophylactic measures can be revisited. The efficacy of the old methods should be tested as complementary tools for the elimination of malaria. PMID:25184997

Val, Fernando Fonseca; Sampaio, Vanderson Souza; Cassera, Maria Belén; Andrade, Raquel Tapajós; Tauil, Pedro Luiz; Monteiro, Wuelton Marcelo; Lacerda, Marcus Vinícius Guimarães

2014-01-01

355

Revisit the spin-FET: Multiple reflection, inelastic scattering, and lateral size effects  

NASA Astrophysics Data System (ADS)

We revisit the spin-injected field effect transistor (spin-FET) in a framework of the lattice model by applying the recursive lattice Green's function approach. In the one-dimensional case the results of simulations in coherent regime reveal noticeable differences from the celebrated Datta-Das model, which lead us to an improved treatment with generalized result. The simulations also allow us to address inelastic scattering and lateral confinement effects in the control of spins. These issues are very important in the spin-FET device.

Xu, Luting; Li, Xin-Qi; Sun, Qing-Feng

2014-12-01

356

Pseudotensor problem of gravitational energy-momentum and Noether's theorem revisited  

E-print Network

Based on a general variational principle, Noether's theorem is revisited. It is shown that the so called pseudotensor problem of the gravitational energy-momentum is a result of mis-reading Noether's theorem, and in fact, all the Noether's conserved quantities are scalars. It is also shown, by using a counter-example, that the non-localizability of gravitational energy-momentum can not be attributed to the equivalence principle. As a direct consequence of variational principle, a generalized Hamilton-Jacobi equation for the Hamilton's principal functional is obtained.

Zhaoyan Wu

2013-11-08

357

Revisiting the Saffman-Taylor Experiment: Imbibition Patterns and Liquid-Entrainment Transitions  

NASA Astrophysics Data System (ADS)

We revisit the Saffman-Taylor experiment focusing on the forced-imbibition regime where the displacing fluid wets the confining walls. We demonstrate a new class of invasion patterns that do not display the canonical fingering shapes. We evidence that these unanticipated patterns stem from the entrainment of thin liquid films from the moving meniscus. We then theoretically explain how the interplay between the fluid flow at the contact line and the interface deformations results in the destabilization of liquid interfaces. In addition, this minimal model conveys a unified framework which consistently accounts for all the liquid-entrainment scenarios that have been hitherto reported.

Levaché, Bertrand; Bartolo, Denis

2014-07-01

358

Revisiting Valley Development on Martian Volcanoes Using MGS and Odyssey Data  

NASA Technical Reports Server (NTRS)

The valley networks found on the slopes of Martian volcanoes represent an interesting subset of the Martian valley networks. Not only do the volcanoes constrain the possible geologic settings, they also provide a window into Martian valley development through time, as the volcanoes formed throughout the geologic history of Mars. Here I take another look at this intriguing subset of networks by revisiting conclusions reached in my earlier studies using the Viking imagery and the valleys on Hawaii as an analog. I then examine more recent datasets.

Gulick, Virginia C.

2005-01-01

359

Long, cold, early r process? Neutrino-induced nucleosynthesis in He shells revisited.  

PubMed

We revisit a ?-driven r-process mechanism in the He shell of a core-collapse supernova, finding that it could succeed in early stars of metallicity Z ? 10?³ Z(?), at relatively low temperatures and neutron densities, producing A ~ 130 and 195 abundance peaks over ~10-20 s. The mechanism is sensitive to the ? emission model and to ? oscillations. We discuss the implications of an r process that could alter interpretations of abundance data from metal-poor stars, and point out the need for further calculations that include effects of the supernova shock. PMID:21668217

Banerjee, Projjwal; Haxton, W C; Qian, Yong-Zhong

2011-05-20

360

Stefan-Boltzmann law for the tungsten filament of a light bulb: Revisiting the experiment  

NASA Astrophysics Data System (ADS)

A classical laboratory experiment to verify the Stefan-Boltzmann radiation law with the tungsten filaments of commercial incandescent lamps has been fully revisited, collecting a fairly large amount of data with a computer-controlled four-channel power supply. In many cases, the total power dissipated by the lamp is well described by a sum of two power-law terms, with one exponent very close to 4, as predicted by the radiation law, and the other very close to 1, as for simple heat conduction. This result was true even for filament surfaces with a shiny metallic appearance, whose emissivity should vary with temperature.

Carlà, Marcello

2013-07-01

361

Revisit the spin-FET: Multiple reflection, inelastic scattering, and lateral size effects.  

PubMed

We revisit the spin-injected field effect transistor (spin-FET) in a framework of the lattice model by applying the recursive lattice Green's function approach. In the one-dimensional case the results of simulations in coherent regime reveal noticeable differences from the celebrated Datta-Das model, which lead us to an improved treatment with generalized result. The simulations also allow us to address inelastic scattering and lateral confinement effects in the control of spins. These issues are very important in the spin-FET device. PMID:25516433

Xu, Luting; Li, Xin-Qi; Sun, Qing-Feng

2014-01-01

362

Revisiting the calibration of manganin gauges for lateral stress measurements in shock-loaded solids  

NASA Astrophysics Data System (ADS)

The calibration of manganin gauges for lateral stress measurements, in shock loaded specimens, is revisited through a simplified analysis, which is based on the dependence of the gauge's strength on shock amplitude. This dependence is derived from the measured resistive hysteresis of the gauge, as obtained in shock and release experiments. The resulting values for the gauge's strength, as a function of shock amplitude, are about half the values which were obtained previously by a different analysis. With the revised strength values, a new calibration curve is derived for the commercial grid-like gauges, as lateral stress transducers in planar impact experiments.

Rosenberg, Z.; Moshel, G.

2014-03-01

363

Progress in Neurobiology 70 (2003) 3352 Nature versus nurture revisited: an old idea with a new twist  

E-print Network

Progress in Neurobiology 70 (2003) 33­52 Nature versus nurture revisited: an old idea with a new The nature versus nurture debate has recently resurfaced with the emergence of the field of developmental molecular neurobiology. The questions associated with "nature" have crystallized into testable hypotheses

Krubitzer, Leah A.

364

Motor Re-Rating for TractionApplications-Field Weakening Revisited Patrick L. Chapman and Philip T.Krein  

E-print Network

enhancements to motor and system performance, much higher power per unit mass, and in general a lowMotor Re-Rating for TractionApplications-Field Weakening Revisited Patrick L. Chapman and Philip T is avoided in an ac drive traction system. Instead, the motor's performance is extended through a reduced

Chapman, Patrick

365

Metal-ion rescue revisited: Biochemical detection of site-bound metal ions important for RNA folding  

E-print Network

Metal-ion rescue revisited: Biochemical detection of site-bound metal ions important for RNA-dimensional architectures of RNA molecules, divalent metal ions populate specific locations, shedding their water molecules make essential contributions to function. Defining the locations of these site-bound metal ions remains

Das, Rhiju

366

Conference: Family Ethics. Partiality Revisited In modern moral philosophy, family issues have first and foremost been addressed within applied and  

E-print Network

questions such as the normative foundations of familial relationships, the scope and content of particularConference: Family Ethics. Partiality Revisited In modern moral philosophy, family issues have to the legitimacy of state intervention into family life. Fewer attention has been paid to more fundamental

Richner, Heinz

367

Ordering in the Site Frustrated Heisenberg Ferromagnet Revisited A.D. Beath and D.H. Ryan  

E-print Network

as a starting point, the question of the magnetic ordering in the site frustrated model with JF A 6= 0 canOrdering in the Site Frustrated Heisenberg Ferromagnet Revisited A.D. Beath and D.H. Ryan #3, Montreal, Quebec H3A 2T8, Canada (November 7, 2002) Monte Carlo simulations of frustrated and non-frustrated

Ryan, Dominic

368

An analytic algorithm for global coverage of the revisiting orbit and its application to the CFOSAT satellite  

NASA Astrophysics Data System (ADS)

This paper addresses a new analytic algorithm for global coverage of the revisiting orbit and its application to the mission revisiting the Earth within long periods of time, such as Chinese-French Oceanic Satellite (abbr., CFOSAT). In the first, it is presented that the traditional design methodology of the revisiting orbit for some imaging satellites only on the single (ascending or descending) pass, and the repeating orbit is employed to perform the global coverage within short periods of time. However, the selection of the repeating orbit is essentially to yield the suboptimum from the rare measure of rational numbers of passes per day, which will lose lots of available revisiting orbits. Thus, an innovative design scheme is proposed to check both rational and irrational passes per day to acquire the relationship between the coverage percentage and the altitude. To improve the traditional imaging only on the single pass, the proposed algorithm is mapping every pass into its ascending and descending nodes on the specified latitude circle, and then is accumulating the projected width on the circle by the field of view of the satellite. The ergodic geometry of coverage percentage produced from the algorithm is affecting the final scheme, such as the optimal one owning the largest percentage, and the balance one possessing the less gradient in its vicinity, and is guiding to heuristic design for the station-keeping control strategies. The application of CFOSAT validates the feasibility of the algorithm.

Xu, Ming; Huang, Li

2014-08-01

369

Revisiting the surface structure of TiO2(110): A quantitative low energy electron diffraction study  

E-print Network

Revisiting the surface structure of TiO2(110): A quantitative low energy electron diffraction study in this study has no significant bearing on the interpretation of the LEED-IV data, in contrast to suggestions in the literature. PACS: 61.14.Hg; 68.35.Bs; 68.47.Gh 2 #12;In order to comprehend, and eventually predict, surface

370

366 ajp.psychiatryonline.org Am J Psychiatry 167:4, April 2010 "Splitting of the Mind" Revisited: Recent  

E-print Network

that schizophrenia is associated with chronically elevated levels of anxiety and stress (5), and paranoid symptoms" Revisited: Recent Neuroimaging Evidence for Functional Dysconnection in Schizophrenia and Its Relation to Symptoms Bleuler coined the term "schizophrenia" to capture the fragmentation and disin- tegration

Park, Sohee

371

Revisiting the 1897 Shillong and 1905 Kangra earthquakes in northern India: Site Response, Moho reflections and a Triggered Earthquake  

E-print Network

1 Revisiting the 1897 Shillong and 1905 Kangra earthquakes in northern India: Site Response, Moho reflections and a Triggered Earthquake Susan E. Hough(1), Roger Bilham(2), Nicolas Ambraseys(3), and Nicole distributions for the Mw8.0 Shillong Plateau earthquake of 1897 and the Mw7.8 Kangra earthquake of 1905

Bilham, Roger

372

696 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 34, NO. 3, JUNE 2006 Revisiting the Anomalous RF Field Penetration Into  

E-print Network

. Electrons can transport the plasma current away from the skin layer due to their thermal motion. As a result696 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 34, NO. 3, JUNE 2006 Revisiting the Anomalous RF Field Penetration Into a Warm Plasma Igor D. Kaganovich, Oleg V. Polomarov, and Constantine E

Kaganovich, Igor

373

6th International OFDM-Workshop (InOWo) 2001, Hamburg 31-1 PAR reduction revisited  

E-print Network

6th International OFDM-Workshop (InOWo) 2001, Hamburg 31-1 PAR reduction revisited: an extension to #12;31-2 6th International OFDM-Workshop (InOWo) 2001, Hamburg y should grow with the PAR limit. High

Henkel, Werner

374

A Digital Humanities Approach to the History of Science Eugenics revisited in hidden debates by means of  

E-print Network

A Digital Humanities Approach to the History of Science Eugenics revisited in hidden debates systematically stud- ied in a single comparative historical project in the subject area of heredity and eugenics the problem of traditional his- torical research that only documents explicitly referring to eugenics issues

de Rijke, Maarten

375

Road work on memory lane--functional and structural alterations to the learning and memory circuit in adults born very preterm.  

PubMed

Very preterm (VPT) birth is considered a risk factor not only for neurological impairment, but also for reduced function in several cognitive domains in childhood and later in life. Individuals who were born VPT are more likely to demonstrate learning and memory difficulties compared to term-born controls. These problems contribute to more VPT-born children repeating grades and underachieving in school. This, in turn, affects their prospects in adult life. Here we aimed to 1) study how the VPT-born adult brain functionally recruited specific areas during learning, i.e. encoding and recall across four repeated blocks of verbal stimuli, and to investigate how these patterns of activation differed from term-born subjects; and 2) probe the microstructural differences of white-matter tracts connecting these areas to other parts of the learning and memory network. To investigate these functional-structural relationships we analyzed functional and diffusion-weighted MRI. Functional-MRI and a verbal paired associate learning (VPAL) task were used to extract Blood Oxygenation Level Dependent (BOLD) activity in 21 VPT-born adults (<33 weeks of gestation) (mean age: 19.68 years ± 0.85; IQ: 99.86 ± 11.20) and 10 term-born controls (mean age: 19.87 years ± 2.04; IQ: 108.9 ± 13.18). Areas in which differences in functional activation were observed between groups were used as seed regions for tractography. Fractional anisotropy (FA) of the tract-skeleton was then compared between groups on a voxel-wise basis. Results of functional MRI analysis showed a significantly different pattern of activation between groups during encoding in right anterior cingulate-caudate body, and during retrieval in left thalamus, hippocampus and parts of left posterior parahippocampal gyrus. The number of correctly recalled word pairs did not statistically differ between individuals who were born VPT and controls. The VPT-born group was found to have reduced FA in tracts passing through the thalamic/hippocampal region that was differently activated during the recall condition, with the hippocampal fornix, inferior longitudinal fasciculus and inferior fronto-occipital fasciculus particularly affected. Young adults who were born very preterm display a strikingly different pattern of activation during the process of learning in key structures of the learning and memory network, including anterior cingulate and caudate body during encoding and thalamus/parahippocampal gyrus during cued recall. Altered activation in thalamus/parahippocampal gyrus may be explained by reduced connections between these areas and the hippocampus, which may be a direct consequence of neonatal hypoxic/ischemic injury. These results could reflect the effect of adaptive plastic processes associated with high-order cognitive functions, at least when the cognitive load remains relatively low, as ex-preterm young adults displayed unimpaired performance in completing the verbal paired associate learning task. PMID:24368264

Salvan, Piergiorgio; Froudist Walsh, Seán; Allin, Matthew P G; Walshe, Muriel; Murray, Robin M; Bhattacharyya, Sagnik; McGuire, Philip K; Williams, Steven C R; Nosarti, Chiara

2014-11-15

376

Revisiting the age of enlightenment from a collective decision making systems perspective  

SciTech Connect

The ideals of the eighteenth century's Age of Enlightenment are the foundation of modern democracies. The era was characterized by thinkers who promoted progressive social reforms that opposed the long-established aristocracies and monarchies of the time. Prominent examples of such reforms include the establishment of inalienable human rights, self-governing republics, and market capitalism. Twenty-first century democratic nations can benefit from revisiting the systems developed during the Enlightenment and reframing them within the techno-social context of the Information Age. This article explores the application of social algorithms that make use of Thomas Paine's (English: 1737--1809) representatives, Adam Smith's (Scottish: 1723--1790) self-interested actors, and Marquis de Condorcet's (French: 1743--1794) optimal decision making groups. It is posited that technology-enabled social algorithms can better realize the ideals articulated during the Enlightenment.

Rodriguez, Marko A [Los Alamos National Laboratory; Watkins, Jennifer H [Los Alamos National Laboratory

2009-01-01

377

Polycarbonate crowns for primary teeth revisited: restorative options, technique and case reports.  

PubMed

Esthetics by definition is the science of beauty - that particular detail of an animate or inanimate object that makes it appealing to the eye. In the modern, civilized, and cosmetically conscious world, well-contoured and well-aligned white teeth set the standard for beauty. Such teeth are not only considered attractive but are also indicative of nutritional health, self esteem, hygienic pride, and economic status. Numerous treatment approaches have been proposed to address the esthetics and retention of restorations in primary teeth. Even though researchers have claimed that certain restorations are better than the others, particularly owing to the issues mentioned above, the search for the ideal esthetic restoration for the primary teeth continues. This paper revisits and attempts to reintroduce the full coverage restoration, namely, polycarbonate crown, for use in primary anterior teeth. PMID:24739917

Venkataraghavan, Karthik; Chan, John; Karthik, Sandhya

2014-01-01

378

Antiresonant reflecting optical waveguide microstructured fibers revisited: a new analysis based on leaky mode coupling  

NASA Astrophysics Data System (ADS)

Using two different modal methods, the multipole method and the more recent fast Fourier factorization method, we exhibit and explain a core mode transition induced by avoided crossing between a core localized leaky mode and an high-index cylinder leaky mode in anti-resonant reflecting optical waveguide microstructured optical fibers (ARROW MOFs). Due to its wavelength selectivity and to the leaky nature of the involved modes, this transition doesn't seem to have already been described in detail and analyzed as done in this work in spite of several already published studies on core mode dispersion properties. The main properties of this transition are also described. We also revisite the already mentionned cut-off phenomena limiting the transmission band in ARROW MOFs in terms of mode coupling between the core mode and one or several high- index cylinder modes.

Renversez, Gilles; Boyer, Philippe; Sagrini, Angelo

2006-06-01

379

Essential Closures and AC Spectra for Reflectionless CMV, Jacobi, and Schrödinger Operators Revisited  

E-print Network

We provide a concise, yet fairly complete discussion of the concept of essential closures of subsets of the real axis and their intimate connection with the topological support of absolutely continuous measures. As an elementary application of the notion of the essential closure of subsets of $\\bbR$ we revisit the fact that CMV, Jacobi, and Schr\\"odinger operators, reflectionless on a set E of positive Lebesgue measure, have absolutely continuous spectrum on the essential closure of the set E (with uniform multiplicity two on E). Though this result in the case of Schr\\"odinger and Jacobi operators is known to experts, we feel it nicely illustrates the concept and usefulness of essential closures in the spectral theory of classes of reflectionless differential and difference operators.

Fritz Gesztesy; Konstantin A. Makarov; Maxim Zinchenko

2008-03-21

380

Simple pendulum dynamics: revisiting the Fourier-based approach to the solution  

E-print Network

The Fourier-based analysis customarily employed to analyze the dynamics of a simple pendulum is here revisited to propose an elementary iterative scheme aimed at generating a sequence of analytical approximants of the exact law of motion. Each approximant is expressed by a Fourier sum whose coefficients are given by suitable linear combinations of Bessel functions, which are expected to be more accessible, especially at an undergraduate level, with respect to Jacobian elliptic functions. The first three approximants are explicitely obtained and compared with the exact solution for typical initial angular positions of the pendulum. In particular, it is shown that, at the lowest approximation level, the law of motion of the pendulum turns out to be adequately described, up to oscillation amplitudes of $\\pi/2$, by a sinusoidal temporal behaviour with a frequency proportional to the square root of the so-called "besinc" function, well known in physical optics.

Borghi, Riccardo

2013-01-01

381

Cosmological Natural Selection Revisited. Some Remarks on the Conceptual Conundrum and Possible Alleys  

E-print Network

Following the selection metaphor as introduced by Lee Smolin in his 1997 book with respect to a possible model of the reproduction of Universes, this model is being reconstructed utilizing the strict analogical form of the metaphor chosen. It is asked then for the genotypal level associated with the primarily phenotypal model, and it is asked in particular where the information processing mechanism of that cosmological sort of selection could actually be found. It is argued that massive black holes in the centres of galaxies may play this important role. Some consequences on black holes in general are discussed then pointing to the necessity to actually revisit the concepts of virtual and actual black holes also.

Rainer E. Zimmermann

2003-04-14

382

The problem of phase mixed shear Alfvén waves in the solar corona revisited  

NASA Astrophysics Data System (ADS)

The problem of phase mixing of shear Alfvén waves is revisited taking into account dissipative phenomena specific for the solar corona. In regions of space plasmas where the dynamics is controlled by the magnetic field, transport coefficients become anisotropic with transport mechanism having different behavior and magnitude depending on the orientation with respect to the ambient magnetic field. Taking into account realistic values for dissipative coefficients we obtain that the previous results derived in context of torsional Alfvén wave phase mixing are actually heavily underestimated so phase mixing cannot be used to explain the damping of torsional Alfvén waves and heating of open coronal structures. The presented results indicate that in order for phase mixing to still be a viable mechanism to explain heating or wave damping unrealistic assumptions have to be made.

Mocanu, G.; Marcu, A.; Ballai, I.; Orza, B.

2008-10-01

383

Re-visit local coupling correction in the interaction regions of RHIC  

SciTech Connect

In this article we will re-visit the local coupling correction in the interaction regions (IRs) of the Relativistic Heavy Ion Collider (RHIC). We will review the measurement data of triplet quadrupole rolls, the local coupling correction strengths in the RHIC control system, and the methods for the local coupling correction with local skew quadrupole correctors. Based on the in-turnnel measurement data of triplet roll errors in 2011, we will analytically calculate and simulate IR-bump method to find out the local skew correction strengths and compare them at store and at injection with the Blue and Yellow ring lattices in the 2011 polarized proton (p-p) and Au-Au runs. The vertical dispersion from the triplet roll errors, local and global coupling correction skew quadrupoles, and the vertical dipole correctors are calculated and discussed.

Luo, Y.; Fischer, W.; Liu, C.; Marusic, A.; Minty, M.; Ptitsyn, V.; Schoefer, V.; Tepikian, S.; Trbojevic, D.; Zimmer, C.

2011-11-01

384

A fussy revisitation of antiprotons as a tool for Dark Matter searches  

E-print Network

Antiprotons are regarded as a powerful probe for Dark Matter (DM) indirect detection and indeed current data from PAMELA have been shown to lead to stringent constraints. However, in order to exploit their constraining/discovery power properly and especially in anticipation of the exquisite accuracy of upcoming data from AMS, great attention must be put into effects (linked to their propagation in the Galaxy) which may be perceived as subleasing but actually prove to be quite relevant. We revisit the computation of the astrophysical background and of the DM antiproton fluxes fully including the effects of: diffusive reacceleration, energy losses including tertiary component and solar modulation (in a force field approximation). We show that their inclusion can somewhat modify the current bounds, even at large DM masses, and that a wrong interpretation of the data may arise if they are not taken into account. The numerical results for the astrophysical background are provided in terms of fit functions; the res...

Boudaud, Mathieu; Giesen, Gaëlle; Salati, Pierre

2014-01-01

385

Radio frequency radiation beam pattern of lightning return strokes: A revisit to theoretical analysis  

NASA Astrophysics Data System (ADS)

Return stroke current pulses can propagate at speeds approaching the speed of light c. Such a fast-moving pulse is expected to radiate differently than conventional dipole emitters. In this study, we revisit the theoretical analysis for the high-speed effect on the radiation beam pattern. Instead of starting with specific return stroke models, as has been done before by other investigators, we start the analysis with a general moving current pulse. Through a simple differential transformation between the retarded time and stationary time/space, the so-called F factor (1 - v cos ?/c)-1 can be readily obtained. This factor is found to be fundamental and is explicitly associated with the radiation beam pattern but is not limited only to the lossless transmission line (TL) return stroke model. It is demonstrated that different beam pattern factors could be derived from this fundamental factor under different return stroke model assumptions.

Shao, Xuan-Min; Jacobson, Abram R.; Fitzgerald, T. Joseph

2004-10-01

386

Revisiting the {P} {T}-symmetric trimer: bifurcations, ghost states and associated dynamics  

NASA Astrophysics Data System (ADS)

In this paper, we revisit one of the prototypical {P} {T}-symmetric oligomers, namely the trimer. We find all the relevant branches of ‘regular’ solutions and analyze the bifurcations and instabilities thereof. Our work generalizes the formulation that was recently proposed in the case of dimers for the so-called ‘ghost states’ of trimers, which we also identify and connect to symmetry-breaking bifurcations from the regular states. We also examine the dynamics of unstable trimers, as well as those of the ghost states in the parametric regime where the latter are found to exist. Finally, we present the current state-of-the-art for optical experiments in {P} {T}-symmetric trimers, as well as experimental results in a gain-loss-gain three channel waveguide structure.

Li, K.; Kevrekidis, P. G.; Frantzeskakis, D. J.; Rüter, C. E.; Kip, D.

2013-09-01

387

Amish Revisited: Next Generation Sequencing Studies of Psychiatric Disorders Among the Plain People  

PubMed Central

The rapid development of next-generation sequencing (NGS) technology has led to renewed interest in the potential contribution of rarer forms of genetic variation to complex, non-Mendelian phenotypes, such as psychiatric illnesses. Although challenging, family-based studies offer some advantages, especially in communities with large families and a limited number of founders. Here we revisit family-based studies of mental illnesses in traditional Amish and Mennonite communities -- known collectively as the Plain people. We discuss the new opportunities for NGS in these populations, with a particular emphasis on investigating psychiatric disorders. We also address some of the challenges facing NGS-based studies of complex phenotypes in founder populations. PMID:23422049

Hou, Liping; Faraci, Gloria; Chen, David T.W.; Kassem, Layla; Schulze, Thomas G.; Shugart, Yin Yao; McMahon, Francis J.

2014-01-01

388

Safe Removal of an Encrusted Nephrostomy Tube Using a Vascular Sheath: A Technique Revisited  

SciTech Connect

With the advent of interventional radiology and the decrease in mortality from chronic ailments, especially malignancy, percutaneous nephrostomy has become a commonly used safe technique for temporary relief of renal tract obstruction or for urinary diversion. However, these are associated with risks of infection, particularly septicaemia, colonisation, and blockage. Another significant complication is difficulty in removal due to encrustation. We describe a useful technique used in our department for the past few years and cite four cases of variable presentation and complexity for removal of an encrusted nephrostomy tube. No mention of this technique was found recent literature. An almost similar technique was described in the 1980s ''Pollack and Banner (Radiology 145:203-205, 1982), Baron and McClennan (Radiology 141:824, 1981)''. It is possible that experienced operators may have used this technique. We revisit it with pictographic representation, describing its use with currently available equipment, for benefit of operators who are not aware of this technique.

Farooq, Ammad, E-mail: faroamm@aol.com; Agarwal, Sanjay; Jones, Vaughan [Wrexham Maelor Hospital, Department of Radiology (United Kingdom)

2013-06-15

389

Revisiting the tunneling spectrum and information recovery of a general charged and rotating black hole  

E-print Network

In this paper we revisit the tunneling spectrum of a charged and rotating black hole--Kerr-Newman black hole by using Parikh and Wilczek's tunneling method and get the most general result compared with the works [9, 10]. We find an ambiguity in Parikh and Wilczek's tunneling method, and give a reasonable description. We use this general spectrum to discuss the information recovery based on the Refs. [11-13]. For the tunneling spectrum we obtained, there exit correlations between sequential Hawking radiations, information can be carried out by such correlations, and the entropy is conserved during the radiation process. So we resolve the information loss paradox based on the methods [11-13] in the most general case.

Chen, Ge-Rui

2015-01-01

390

A new approach for agroecosystems monitoring using high-revisit multitemporal satellite data series  

NASA Astrophysics Data System (ADS)

With increasing population pressure throughout the world and the need for increased agricultural production there is a definite need for improved management of the world's agricultural resources. Comprehensive, reliable and timely information on agricultural resources is necessary for the implementation of effective management decisions. In that sense, the demand for high-quality and high-frequency geo-information for monitoring of agriculture and its associated ecosystems has been growing in the recent decades. Satellite image data enable direct observation of large areas at frequent intervals and therefore allow unprecedented mapping and monitoring of crops evolution. Furthermore, real time analysis can assist in making timely management decisions that affect the outcome of the crops. The DEIMOS-1 satellite, owned and operated by ELECNOR DEIMOS IMAGING (Spain), provides 22m, 3-band imagery with a very wide (620-km) swath, and has been specifically designed to produce high-frequency revisit on very large areas. This capability has been proved through the contracts awarded to Airbus Defence and Space every year since 2011, where DEIMOS-1 has provided the USDA with the bulk of the imagery used to monitor the crop season in the Lower 48, in cooperation with its twin satellite DMCii's UK-DMC2. Furthermore, high density agricultural areas have been targeted with increased frequency and analyzed in near real time to monitor tightly the evolution. In this paper we present the results obtained from a campaign carried out in 2013 with DEIMOS-1 and UK-DMC2 satellites. These campaigns provided a high-frequency revisit of target areas, with one image every two days on average: almost a ten-fold frequency improvement with respect to Landsat-8. The results clearly show the effectiveness of a high-frequency monitoring approach with high resolution images with respect to classic strategies where results are more exposed to weather conditions.

Diez, M.; Moclán, C.; Romo, A.; Pirondini, F.

2014-10-01

391

F center in lithium fluoride revisited: Comparison of solid-state physics and quantum-chemistry approaches  

NASA Astrophysics Data System (ADS)

We revisit the theoretical description of the F color center in lithium fluoride employing advanced complementary ab initio techniques. We compare the results from periodic supercell calculations involving density-functional theory (DFT) and post-DFT techniques with those from the embedded-cluster approach involving quantum-chemical many-electron wave-function techniques. These alternative approaches yield results in good agreement with each other and with the experimental data provided that correlation effects are properly taken into account.

Karsai, Ferenc; Tiwald, Paul; Laskowski, Robert; Tran, Fabien; Koller, David; Gräfe, Stefanie; Burgdörfer, Joachim; Wirtz, Ludger; Blaha, Peter

2014-03-01

392

Ferret badger rabies origin and its revisited importance as potential source of rabies transmission in Southeast China  

Microsoft Academic Search

BACKGROUND: The frequent occurrence of ferret badger-associated human rabies cases in southeast China highlights the lack of laboratory-based surveillance and urges revisiting the potential importance of this animal in rabies transmission. To determine if the ferret badgers actually contribute to human and dog rabies cases, and the possible origin of the ferret badger-associated rabies in the region, an active rabies

Ye Liu; Shoufeng Zhang; Xianfu Wu; Jinghui Zhao; Yanli Hou; Fei Zhang; Andres Velasco-Villa; Charles E Rupprecht; Rongliang Hu

2010-01-01

393

Does public sector efficiency matter? Revisiting the relation between fiscal size and economic growth in a world sample  

Microsoft Academic Search

This paper revisits the relationship between fiscal size and economic growth. Our work differs from the empirical growth literature because this relationship depends explicitly on the efficiency of the public sector. We use a sample of 64 countries, both developed and developing, in four 5-year time-periods over 1980-2000. Building on the work of Afonso, Schuknecht and Tanzi (2005), we construct

Konstantinos Angelopoulos; Apostolis Philippopoulos; Efthymios Tsionas

2007-01-01

394

A revisit of the papers on the theory of relativity: Reconsideration of the hypothesis of ether-dragging  

E-print Network

This paper revisits previous papers related to the theory of relativity. Afterwards, a reconsideration of the hypothesis of ether-dragging is discussed. The ether is compatible with the theory of relativity and historical experiments; this paper explains the Michelson-Morley experiment using the ether-dragging hypothesis without the orthodox interpretation that the speed c is a fixed constant in terms of any system of inertial coordinates.

Masanori Sato

2009-11-13

395

White Matter Microstructure in Superior Longitudinal Fasciculus Associated with Spatial Working Memory Performance in Children  

ERIC Educational Resources Information Center

During childhood and adolescence, ongoing white matter maturation in the fronto-parietal cortices and connecting fiber tracts is measurable with diffusion-weighted imaging. Important questions remain, however, about the links between these changes and developing cognitive functions. Spatial working memory (SWM) performance improves significantly…

Vestergaard, Martin; Madsen, Kathrine Skak; Baare, William F. C.; Skimminge, Arnold; Ejersbo, Lisser Rye; Ramsoy, Thomas Z.; Gerlach, Christian; Akeson, Per; Paulson, Olaf B.; Jernigan, Terry L.

2011-01-01

396

MR features of the developing perianterior horn structure including subcallosal fasciculus in infants and children  

Microsoft Academic Search

Introduction  To describe the changes in the magnetic resonance (MR) signal of the perianterior horn structure (PAS) with increasing age,\\u000a we studied 69 infants and children aged between 3 days and 9.4 years (average: 2.8 years) without any neurological deficits.\\u000a \\u000a \\u000a \\u000a Methods  T1- and T2-weighted images and FLAIR (fluid attenuation inversion recovery) images were obtained in the axial plane. Based\\u000a on a comparison

Hidetsuna Utsunomiya; Yasuhiro Nakamura

2007-01-01

397

Cingulate Fasciculus Integrity Disruption in Schizophrenia: A Magnetic Resonance Diffusion Tensor Imaging Study  

PubMed Central

Background Evidence suggests that a disruption in limbic system network integrity and, in particular, the cingulate gyrus (CG), may play a role in the pathophysiology of schizophrenia; however, the cingulum bundle (CB), the white matter tract furnishing both input and output to CG, and the most prominent white matter fiber tract in the limbic system, has not been evaluated in schizophrenia using the new technology of diffusion tensor imaging (DTI). Methods We used line scan DTI to evaluate diffusion in the CB in 16 male schizophrenia patients and 18 male control subjects, group-matched for age, parental socioeconomic status, and handedness. We acquired 4-mm-thick coronal slices through the entire brain. Maps of fractional anisotropy (FA) were generated to quantify diffusion within the left and right CB on eight slices that included the central portion of the CB. Results Results showed group differences, bilaterally, in area and mean FA for CB, where patients showed smaller area and less anisotropy than controls. For patients, decreased left CB correlated significantly with attention and working memory measures as assessed by the Wisconsin Card Sorting Test. Conclusions These data provide strong evidence for CB disruptions in schizophrenia, which may be related to disease-related attention and working memory abnormalities. PMID:14643084

Kubicki, Marek; Westin, Carl-Fredrik; Nestor, Paul G.; Wible, Cynthia G.; Frumin, Melissa; Maier, Stephan E.; Kikinis, Ron; Jolesz, Ferenc A.; McCarley, Robert W.; Shenton, Martha E.

2009-01-01

398

Diffusion Tensor Imaging of the Superior Longitudinal Fasciculus and Working Memory  

E-print Network

). Further, these cognitive deficits are not widely responsive to neuroleptics. While atypical antipsychotics are more effective in this domain than traditional antipsychotics, impairments may persist even after

Poldrack, Russ

399

Beyond the Arcuate Fasciculus: Consensus and Controversy in the Connectional Anatomy of Language  

ERIC Educational Resources Information Center

The growing consensus that language is distributed into large-scale cortical and subcortical networks has brought with it an increasing focus on the connectional anatomy of language, or how particular fibre pathways connect regions within the language network. Understanding connectivity of the language network could provide critical insights into…

Dick, Anthony Steven; Tremblay, Pascale

2012-01-01

400

Clementine revisited  

NASA Astrophysics Data System (ADS)

NASA administrator Daniel S. Goldin is pushing for a sequel to Clementine, the joint Defense Department-NASA probe that successfully produced the most detailed topographic map of Moon ever filmed earlier this year. While a smash with scientists, the first Clementine mission was also a hit at the box office with its thrifty 80 million price tag. Clementine 2 would also come in under 100 million. The destination of Clementine 2 is under discussion. A top candidate is a Moon landing, which may help settle the question whether there is ice in the Moon's craters. Filming an asteroid and filming the Earth are the other leading options, according to Stewart Nozette, deputy program manager, Ballistic Missile Defense Organization. Although the second portion of Clementine's mission to map the asteroid Geographos failed, Clementine 2 would have the benefit of the lessons learned from number one, which is now in "cold storage" in an orbit around the Sun.

401

Pseudodiagnosticity Revisited  

ERIC Educational Resources Information Center

In the psychology of reasoning and judgment, the pseudodiagnosticity task has been a major tool for the empirical investigation of people's ability to search for diagnostic information. A novel normative analysis of this experimental paradigm is presented, by which the participants' prevailing responses turn out not to support the generally…

Crupi, Vincenzo; Tentori, Katya; Lombardi, Luigi

2009-01-01

402

Pulfrich revisited  

Microsoft Academic Search

The Pulfrich phenomenon is a stereo-illusion resulting from latency disparities in the visual pathways. It is common after optic neuritis, but is also to be found with other conditions. The symptoms are often difficult for the patient to explain and for the physician to understand. Symptoms may be sufficiently disturbing to significantly interfere with a patient's life (e.g., prevention of

Charles J. M. Diaper

1997-01-01

403

Speechreading Revisited  

ERIC Educational Resources Information Center

Although speechreading has always served an important role in the communication of deaf people, educational interest in speechreading has decreased in recent decades. This paper reviews speechreading in terms of speech processing, neural activity and literacy, and suggests that it has an important role in intervention programmes for all deaf…

Woll, Bencie

2012-01-01

404

Ortega Revisited.  

ERIC Educational Resources Information Center

Reexamines Ortega y Gasset's proposition that the professional role of the librarian is to act as a selective "filter between man and the torrent of books." Responsibilities of the librarian in light of the increasing volume of information, increases in speed of access to information, and information overload, are discussed. (Author/JL)

Asheim, Lester

1982-01-01

405

Interpolation revisited.  

PubMed

Based on the theory of approximation, this paper presents a unified analysis of interpolation and resampling techniques. An important issue is the choice of adequate basis functions. We show that, contrary to the common belief, those that perform best are not interpolating. By opposition to traditional interpolation, we call their use generalized interpolation; they involve a prefiltering step when correctly applied. We explain why the approximation order inherent in any basis function is important to limit interpolation artifacts. The decomposition theorem states that any basis function endowed with approximation order can be expressed as the convolution of a B-spline of the same order with another function that has none. This motivates the use of splines and spline-based functions as a tunable way to keep artifacts in check without any significant cost penalty. We discuss implementation and performance issues, and we provide experimental evidence to support our claims. PMID:11055789

Thévenaz, P; Blu, T; Unser, M

2000-07-01

406

Pearlite revisited  

NASA Astrophysics Data System (ADS)

Zener's model of pearlite transformation in steels can be viewed as the prototype of many microstructure evolution models in materials science. It links principles of thermodynamics and kinetics to the scale of the microstructure. In addition it solves a very practical problem: How the hardness of steel is correlated to the conditions of processing. Although the model is well established since the 1950s, quantitative explanation of growth kinetics was missing until very recently. The present paper will shortly review the classical model of pearlite transformation. Zener's conjecture of maximum entropy production will be annotated by modern theoretical and experimental considerations of a band of stable (sometimes oscillating) states around the state of maximum entropy production. Finally, an explanation of the growth kinetics observed in experiments is proposed based on diffusion fluxes driven by stress gradients due to large transformation strain.

Steinbach, Ingo; Plapp, Mathis

2012-11-01

407

Leukemia revisited  

SciTech Connect

Selected features of the historical development of our knowledge of leukemia are discussed. The use of different methodologies for study of the nature of leukemic cell proliferation are analyzed. The differences between older cell kinetic data using tritiated thymidine and autoradiography and the newer cell culture methods are more apparent than real. It is suggested that tritiated thymidine and extracorporeal irradiation of the blood may be useful for therapeutic agents that have not been given an adequate trial. Radiation leukemogenesis presents an opportunity for study of the nature of leukemogenesis that has not been exploited adequately.

Cronkite, E P

1980-01-01

408

Pestalotiopsis revisited  

PubMed Central

Species of Pestalotiopsis occur commonly as plant pathogens, and represent a fungal group known to produce a wide range of chemically novel, diverse metabolites. In the present study, we investigated 91 Pestalotiopsis isolates from the CBS-KNAW Fungal Biodiversity Centre (CBS) culture collection. The phylogeny of the Amphisphaeriaceae was constructed based on analysis of 28S nrRNA gene (LSU) sequence data, and taxonomic changes are proposed to reflect more natural groupings. We combined morphological and DNA data, and segregated two novel genera from Pestalotiopsis, namely Neopestalotiopsis and Pseudopestalotiopsis. The three genera are easily distinguishable on the basis of their conidiogenous cells and colour of their median conidial cells. We coupled morphological and combined sequence data of internal transcribed spacer (ITS), partial ?-tubulin (TUB) and partial translation elongation factor 1-alpha (TEF) gene regions, which revealed 30 clades in Neopestalotiopsis and 43 clades in Pestalotiopsis. Based on these data, 11 new species are introduced in Neopestalotiopsis, 24 in Pestalotiopsis, and two in Pseudopestalotiopsis. Several new combinations are proposed to emend monophyly of Neopestalotiopsis, Pestalotiopsis and Pseudopestalotiopsis. PMID:25492988

Maharachchikumbura, S.S.N.; Hyde, K.D.; Groenewald, J.Z.; Xu, J.; Crous, P.W.

2014-01-01

409

Brezinaite Revisited  

NASA Astrophysics Data System (ADS)

Brezinaite Data: Idealized formula: (Cr^2+Cr^3+)(sub)3S(sub)4, metal: sulphur ratio=0.76 - 0.79, structure: defect NiAs-type, symmetry: monoclinic I 2/m, Beta = 91 degrees 32'. As part of a research program in Copenhagen and at the Smithsonian Institution involving sulphides in selected irons, the mineral brezinaite was, quite surprisingly, found to be present in several of the sections studied. Brezinaite is a rare meteoritic sulphide, previously only reported in two Anom. irons; Tucson [1] and New Baltimore [2] , a list that can now be extended to include, as a minimum, the following meteorites: Type IIIA; Costilla Peak, Kalkaska and Murfreesboro. Type IVA; Jamestown, La Grange and Western Arkansas. Anom. or type IIIF; Saint Genevieve County. A thin section examination by reflected light alone will not always be enough to identify the mineral with sufficient accuracy, and it is, therefore, only meteorites in which brezinaite has been confirmed by microprobe analysis that are mentioned above. With the exception of Tucson, where brezinaite is frequently found as anhedral grains contiguous to silicate inclusions, its typical occurrence is either in or along sub-boundaries of the kamacite bands, or occasionally within comb- structured plessite fields. Brezinaite appears most commonly as minute (5-200 micrometers) anhedral-subhedral greyish colored grains, occasionally with a partial rim of schreibersite (eg., Murfreesboro), that occur freely scattered throughout the metal matrix. With the notable exception of troilite aggregates, in which brezinaite does not occur, its appearance and occurrence coincide with the common mineral daubreelite (VH~400 and R% = 37- 40). The difficulty in distinguishing between these two minerals has been a source of confusion. The present study shows that the two minerals both occur as isolated grains and in the immediate vicinity of each other. The intimate relationship between the two minerals is especially clear in Costilla Peak where one (180/120 micrometer) grain was found to consist of alternating thin lamellae of daubreelite and brezinaite. Such lamellae cannot, however, be distinguished in reflected light! Brezinaite does, however, have several distinctive features that are of diagnostic value in separating it from daubreelite. Brezinaite possesses a high degree of anisotropy that may vary from barely detectable to very pronounced, due to differing optical orientations. In general, brezinaite is not abundant in any one thin section, thus unfavorably oriented grains can be mistaken for daubreelite. More characteristic is the quite frequent display of polysynthetic twins in brezinaite, eg., Tucson, Western Arkansas, and to a lesser degree Jamestown. The twinned character is most commonly seen as two sets of parallel lamallae, almost at right angles to one another. Occasionally a third set of more irregular twins can be seen to intersect the two former at an oblique angle, as shown in Fig. 1. References: [1] Bunch T. E. and Fuchs L. H. (1969) Am. Miner., 54, 1509-1518. [2] Buchwald V. F. (1975) I-III, University of California, 1-1418. Fig. 1, which appears here in the hard copy, shows twinned brezinaite bordering a silicate inclusion in the Tucson meteorite. Crossed nicols, X 400. In a future study it is planned to cross-examine the Fe-Cr sulphides with a view to improve our understanding of iron meteorites at moderate to low temperatures.

Davis, D. E.

1993-07-01

410

Coadaptation revisited  

SciTech Connect

During the four decades or more since Dobzhansky introduced the term 'coadaptation' to refer to the commonly observed selective superiority of inversion heterozygotes in populations of Drosophila pseudoobscura, the definition of the term has evolved, as have views concerning the rapidity with which coadaptation might occur. Indeed, the paucity of demonstrated instances of linkage disequilibrium in natural populations has led many to dismiss coadaptation as a factor in evolutionary change. The present article reviews the reasons why coadaptation (and the equivalent expression, 'integration of gene pools') was proposed as a phenomenon occurring in local (or experimental) populations, offers supporting data obtained through a reanalysis of data on irradiated populations of D. melanogaster, and concludes that sound evidence supports coadaptation as a factor in the genetic change of populations.65 references.

Wallace, B. (Virginia Polytechnic Institute and State Univ., Blacksburg (USA))

1991-03-01

411

Turbulence revisited  

Microsoft Academic Search

A new approach to turbulence based upon the Stabilization Principle is introduced. Onset of turbulence is interpreted as loss of stability of solutions to the Navier–Stokes equations in the class of differentiable functions. Developed turbulence is considered as postinstability motion in the class of non-differentiable functions. A non-linear version of the Liouville equation is proposed for describing postinstability motions of

Michail Zak

2009-01-01

412

Cheiloscopy: Revisited  

PubMed Central

Identification plays a very important role in any crime investigation. Cheiloscopy helps in identifying the humans based on the lips’ traces. The pattern of wrinkles on the lips has individual characteristics like fingerprints. A review of the literature reveals very little research done on lip prints so far. The present article reviews in detail the history, scope of cheiloscopy, and the use of lip prints in crime detection. It also highlights the current research carried out in the field of cheiloscopy. An effort has been made to help the researchers by reviewing in detail the various methods of classifying and analyzing the lip prints. It concludes by enlightening the readers with the fact that the possibilities to use the red part of lips to identify a human being are wider than it is commonly thought. PMID:23087583

Prabhu, Rachana V; Dinkar, Ajit D; Prabhu, Vishnudas Dinesh; Rao, Prasanna Kumar

2012-01-01

413

Marijuana Revisited.  

ERIC Educational Resources Information Center

This review examines recent research on psychological effects of marijuana. The article contains material on potency, research problems, use patterns in the United States, and expectancy, as well as a review of research on acute effects, including psychosis, toxic delirium, acute anxiety, and brain damage. (Author)

Archer, James, Jr.; Lopata, Ann

1979-01-01

414

Pestalotiopsis revisited.  

PubMed

Species of Pestalotiopsis occur commonly as plant pathogens, and represent a fungal group known to produce a wide range of chemically novel, diverse metabolites. In the present study, we investigated 91 Pestalotiopsis isolates from the CBS-KNAW Fungal Biodiversity Centre (CBS) culture collection. The phylogeny of the Amphisphaeriaceae was constructed based on analysis of 28S nrRNA gene (LSU) sequence data, and taxonomic changes are proposed to reflect more natural groupings. We combined morphological and DNA data, and segregated two novel genera from Pestalotiopsis, namely Neopestalotiopsis and Pseudopestalotiopsis. The three genera are easily distinguishable on the basis of their conidiogenous cells and colour of their median conidial cells. We coupled morphological and combined sequence data of internal transcribed spacer (ITS), partial ?-tubulin (TUB) and partial translation elongation factor 1-alpha (TEF) gene regions, which revealed 30 clades in Neopestalotiopsis and 43 clades in Pestalotiopsis. Based on these data, 11 new species are introduced in Neopestalotiopsis, 24 in Pestalotiopsis, and two in Pseudopestalotiopsis. Several new combinations are proposed to emend monophyly of Neopestalotiopsis, Pestalotiopsis and Pseudopestalotiopsis. PMID:25492988

Maharachchikumbura, S S N; Hyde, K D; Groenewald, J Z; Xu, J; Crous, P W

2014-09-01

415

Einstein Revisited  

ERIC Educational Resources Information Center

A brief description on the work and life of the great physicist scientist Albert Einstein is presented. The photoelectric paper written by him in 1905 led him to the study of fluctuations in the energy density of radiation and from there to the incomplete nature of the equipartition theorem of classical mechanics, which failed to account for…

Fine, Leonard

2005-01-01

416

Endosymbiosis Revisited.  

ERIC Educational Resources Information Center

Presents insights into the endosymbiotic theory based on a re-examination of evidence from investigations into the archaebacteria and other strange organisms inhabiting the hindguts of wood-eating insects. Examines the mechanism of evolutionary change and the speed with which it occurs. (RT)

Tribe, Michael A.

1988-01-01

417

Relapse revisited  

Microsoft Academic Search

Rather little is known about the changes in orthodontic treatment results exceeding a decade after treatment. The purpose of this study was to quantify changes in tooth relationships in a series of cases (n = 36) at 6 years and again at 15 years after treatment. The rate of change decreased with time, supporting the contention that most “relapse” occurs

James L. Vaden; Edward F. Harris; Roberta L. Zeigler Gardner

1997-01-01

418

Balloons Revisited  

ERIC Educational Resources Information Center

Whilst everyone is familiar with the process of blowing up a balloon, few of us have gone further to quantify the actual pressures involved at different stages in the inflation process. This paper seeks to describe experiments to fill some of those gaps and examine some of the apparently anomalous behaviour of connected balloons. (Contains 12…

Jeskova, Z.; Featonby, D.; Fekova, V.

2012-01-01

419

Regression Revisited  

Microsoft Academic Search

Sir Francis Galton introduced median regression and the use of the quantile function to describe distributions. Very early on the tradition moved to mean regression and the universal use of the Normal distribution, either as the natural 'error' distribution or as one forced by transformation. Though the introduction of 'quantile regression' refocused attention on the shape of the variability about

Warren Gilchrist

2008-01-01

420

Tracks Revisited.  

ERIC Educational Resources Information Center

Describes a contemporary adaptation of the "Footprint Puzzle," whigh was first developed in the 1960s for the Earth Science Curriculum Project. Students sequentially look at three frames of track drawings. For each frame, students first list observations and then make inferences about the observations. (PR)

Scarnati, James T.

1993-01-01

421

Siphons, Revisited  

ERIC Educational Resources Information Center

The siphon is a very useful example of early technology, the operation of which has long been well understood. A recent article makes the claim that established beliefs regarding this device are incorrect and proposes a "chain model" in which intermolecular forces within the fluid play a large role while atmospheric pressure does not. We have…

Richert, Alex; Binder, P. -M.

2011-01-01

422

1948 revisited  

SciTech Connect

This paper describes what is was like to be a graduate student in 1948 when heavy nuceli were discovered in primary cosmic rays from balloon flights carrying cloud chambers from 68,000 to 101,000 feet in altitude. (AIP)

Freier, P.S. (University of Minnesota, Minneapolis, MN 55455 (USA))

1989-03-01

423

Revisiting the chemical reactivity indices as the state function derivatives. The role of classical chemical hardness.  

PubMed

The chemical reactivity indices as the equilibrium state-function derivatives are revisited. They are obtained in terms of the central moments (fluctuation formulas). To analyze the role of the chemical hardness introduced by Pearson [J. Am. Chem. Soc. 105, 7512 (1983)], the relations between the derivatives up to the third-order and the central moments are obtained. As shown, the chemical hardness and the chemical potential are really the principal indices of the chemical reactivity theory. It is clear from the results presented here that the chemical hardness is not the derivative of the Mulliken chemical potential (this means also not the second derivative of the energy at zero-temperature limit). The conventional quadratic dependence of energy, observed at finite temperature, reduces to linear dependence on the electron number at zero-temperature limit. The chemical hardness plays a double role in the admixture of ionic states to the reference neutral state energy: it determines the amplitude of the admixture and regulates the damping of its thermal factor. PMID:25662633

Malek, Ali; Balawender, Robert

2015-02-01

424

The Twin Paradox Revisited and Reformulated -- On the Possibility of Detecting Absolute Motion  

E-print Network

The famous twin paradox of the Special Theory of Relativity by Einstein (1905) is revisited and revised. This paradox is not a paradox in the true sense of a paradox but a reflection of a misunderstanding of the problem and the Principle of Relativity. The currently accepted solution to this takes into account the accelerations and deceleration of the traveling twin thus introducing an asymmetry that solves the paradox. We argue here that, with the acceleration and deceleration neglected, the problem is asymmetric hence leading to the same conclusion that the traveling twin will age less than the stay at home. We introduce a symmetric twin paradox whose solution can not be found within the currently accepted provinces of the STR if one adopts the currently accepted philosophy of the STR namely that it is impossible for an inertial observer to determine their state of motion. To resolve this, we present (in our modest view) a simple and convincing argument that leads us to conclude that it must be possible for an inertial observer to determine their own state of motion. With this, we are able to solve the symmetric twin paradox. The fact that it is possible for an inertial observer to determine their state of motion -- brings us back to the long rejected idea of an all pervading and permeating medium -- the Aether, namely the Lorentz luminiferous Aether. An experiment capable of validating or invalidating this claim is suggested.

G. G. Nyambuya; M. D. Ngobeni

2008-09-06

425

Revisiting the method to obtain the mechanical properties of hydrided fuel cladding in the hoop direction  

NASA Astrophysics Data System (ADS)

The method reported in the literature to calculate the stress-strain curve of nuclear fuel cladding from ring tensile test is revisited in this paper and a new alternative is presented. In the former method, two universal curves are introduced under the assumption of small strain. In this paper it is shown that these curves are not universal, but material-dependent if geometric nonlinearity is taken into account. The new method is valid beyond small strains, takes geometric nonlinearity into consideration and does not need universal curves. The stress-strain curves in the hoop direction are determined by combining numerical calculations with experimental results in a convergent loop. To this end, ring tensile tests were performed in unirradiated hydrogen-charged samples. The agreement among the simulations and the experimental results is excellent for the range of concentrations tested (up to 2000 wppm hydrogen). The calculated stress-strain curves show that the mechanical properties do not depend strongly on the hydrogen concentration, and that no noticeable strain hardening occurs. However, ductility decreases with the hydrogen concentration, especially beyond 500 wppm hydrogen. The fractographic results indicate that as-received samples fail in a ductile fashion, whereas quasicleavage is observed in the hydrogen-charged samples.

Martín-Rengel, M. A.; Gómez Sánchez, F. J.; Ruiz-Hervías, J.; Caballero, L.; Valiente, A.

2012-10-01

426

Re-visiting of plentiful food sources and food search strategies in desert ants.  

PubMed

North African desert ants, Cataglyphis fortis, are established model organisms in animal navigation research. Cataglyphis re-visit plentiful feeding sites, but their decision to return to a feeder and the organization of food searches has been little studied. Here we provide a review of recent advances regarding this topic. At least two parameters determine the ants' assessment of site quality, namely, amount of food available and reliability of food encounter on subsequent visits. The amount of food appears to be judged by the concentration of items at the food uptake site. Initially the amount of food in a feeder dominates the foragers' decision to return, whereas learning about reliability takes precedence in the course of a few visits. The location of a worthwhile site is determined by the animals' path integration system. In particular, the distance of the feeding site is memorized as the arithmetic average of the distances covered during the previous outbound and homebound journeys. Feeding sites that are small and inconspicuous cannot be approached directly with sufficient certainty, due to inevitable inaccuracies of the path integrator. Instead, desert ants steer downwind of the goal to encounter the odor plume emanating from the food and they follow this plume to the feeder. The angle steered downwind reflects the animals' maximal navigation error and is adjusted according to experience. In summary, food searches of desert ants provide an unexpected wealth of features that may advance our understanding of search, navigation, and decision strategies. There are several aspects that warrant further scrutiny. PMID:22783163

Wolf, Harald; Wittlinger, Matthias; Bolek, Siegfried

2012-01-01

427

Revisiting the implications of CPT and unitarity for baryogenesis and leptogenesis  

E-print Network

In the context of GUT baryogenesis models, a well-known theorem asserts that CPT conservation and the unitarity of S-matrix require that the lowest order contribution that leads to the generation of a non-zero net CP-violation via the decay of a heavy particle must be to $\\mathcal{O}({\\alpha_\\slashed{B}}^3)$, where $\\alpha_\\slashed{B}$ is a baryon number (B) violating coupling. We revisit this theorem (which holds for lepton number (L) violation, and hence for leptogenesis as well) and examine its implications for models where the particle content allows the heavy particle to also decay via modes which conserve B (or L) in addition to modes which do not. We systematically expand the S-matrix order by order in B\\slash L-violating couplings, and show, in such cases, that the net CP-violation is non-zero even to $\\mathcal{O}({\\alpha_\\slashed{B}}^2)$, without actually contradicting the theorem. By replacing a B/L violating coupling (usually constrained to be small) by a relatively unconstrained B/L conserving one, our result may allow for sufficient CP violation in models where it may otherwise have been difficult to generate the observed baryon asymmetry. As an explicit application of this result, we construct a model in low-scale leptogenesis.

Atri Bhattacharya; Raj Gandhi; Satyanarayan Mukhopadhyay

2014-06-04

428

Benchmarking ventricular arrhythmias in the mouse--revisiting the 'Lambeth Conventions' 20 years on.  

PubMed

The isolated Langendorff-mode perfused heart has become a valuable experimental model, used extensively to examine cardiac function, pathophysiology and pharmacology. For the clinical cardiologist an ECG is often a simple practicality, however in experimental circumstances, particularly with ex vivo murine hearts it is not always possible to obtain an ECG due to experimental recording constraints. However, the mechanical record of ventricular contractile function can be highly informative in relation to electrical state. It is difficult though to achieve consistency in these evaluations of arrhythmia as a validated common reference framework is lacking. In 1988, a group of investigators developed the 'Lambeth Conventions'--a standardised reference for the definition and classification of arrhythmias in animal experimental models of ischaemia, infarction and reperfusion in vivo. Now, two decades later it is timely to revisit the Lambeth Conventions, and to update the guidelines in the context of the marked increase in murine heart study in experimental cardiac pathophysiology. Here we describe an adjunct to the Lambeth Conventions for the reporting of ventricular arrhythmias post-ischaemia in ex vivo mouse hearts when ECG recordings are not employed. Of seven discrete and identifiable patterns of mechanical dysrhythmia observed in reperfusion, five could be classified using conventional ECG terminology: ventricular premature beat, bigeminy, trigeminy, ventricular tachycardia and ventricular fibrillation. Two additional rhythm variations detected from the pressure record are described (potentiated contraction and alternans). PMID:18951062

Huggins, Catherine E; Bell, James R; Pepe, Salvatore; Delbridge, Lea M D

2008-12-01

429

The Eating Attitudes Test-26 revisited using exploratory structural equation modeling.  

PubMed

Most previous studies have failed to replicate the original factor structure of the 26-item version of the Eating Attitudes Test (EAT-26) among community samples of adolescents. The main objective of the present series of four studies (n?=?2178) was to revisit the factor structure of this instrument among mixed gender community samples of adolescents using both exploratory structural equation modeling (ESEM) and confirmatory factor analysis (CFA). First, results from the ESEM analyses provided satisfactory goodness-of-fit statistics and reliability coefficients for a six-factor model of the EAT with 18 items (EAT-18) closely corresponding to the original seven-factor structure proposed for the 40-item version of the EAT. Second, these analyses were satisfactorily replicated among a new sample of community adolescents using CFA. The results confirmed the factor loading and intercept invariance of this model across gender and age groups (i.e., early and late adolescence), as well as the complete invariance of the EAT-18 measurement model between ethnicities (i.e., European versus African origins) and across weight categories (i.e., underweight, normal weight and overweight). Finally, the last study provided support for convergent validity of the EAT-18 with the Eating Disorder Inventory and with instruments measuring global self-esteem, physical appearance, social physique anxiety and fear of negative appearance evaluation. PMID:23344702

Maïano, Christophe; Morin, Alexandre J S; Lanfranchi, Marie-Christine; Therme, Pierre

2013-07-01

430

Revisiting the implications of CPT and unitarity for baryogenesis and leptogenesis  

NASA Astrophysics Data System (ADS)

In the context of Grand Unified Theories (GUT) baryogenesis models, a well-known theorem asserts that CPT conservation and the unitarity of the S matrix require that the lowest order contribution that leads to the generation of a nonzero net CP violation via the decay of a heavy particle must be to O(?B3), where ?B is a baryon number (B) violating coupling. We revisit this theorem [which holds for lepton number (L) violation, and hence for leptogenesis as well] and examine its implications for models where the particle content allows the heavy particle to also decay via modes which conserve B (or L) in addition to modes which do not. We systematically expand the S matrix order by order in B/L violating couplings, and show, in such cases, that the net CP violation is nonzero even to O(?B2), without actually contradicting the theorem. By replacing a B/L violating coupling (usually constrained to be small) by a relatively unconstrained B/L conserving one, our result may allow for sufficient CP violation in models where it may otherwise have been difficult to generate the observed baryon asymmetry. As an explicit application of this result, we construct a model in low-scale leptogenesis.

Bhattacharya, Atri; Gandhi, Raj; Mukhopadhyay, Satyanarayan

2014-06-01

431

Revisiting the total ion yield x-ray absorption spectra of liquid water microjets.  

PubMed

Measurements of the total ion yield (TIY) x-ray absorption spectrum (XAS) of liquid water by Wilson et al (2002 J. Phys.: Condens. Matter 14 L221 and 2001 J. Phys. Chem. B 105 3346) have been revisited in light of new experimental and theoretical efforts by our group. Previously, the TIY spectrum was interpreted as a distinct measure of the electronic structure of the liquid water surface. However, our new results indicate that the previously obtained spectrum may have suffered from as yet unidentified experimental artifacts. Although computational results indicate that the liquid water surface should exhibit a TIY-XAS that is fundamentally distinguishable from the bulk liquid XAS, the new experimental results suggest that the observable TIY-XAS is actually nearly identical in appearance to the total electron yield (TEY-)XAS, which is a bulk probe. This surprising similarity between the observed TIY-XAS and TEY-XAS likely results from large contributions from x-ray induced electron stimulated desorption of ions, and does not necessarily indicate that the electronic structure of the bulk liquid and liquid surface are identical. PMID:21694286

Cappa, Christopher D; Smith, Jared D; Wilson, Kevin R; Saykally, Richard J

2008-05-21

432

Dual beta-lactam therapy for serious Gram-negative infections: is it time to revisit?  

PubMed

We are rapidly approaching a crisis in antibiotic resistance, particularly among Gram-negative pathogens. This, coupled with the slow development of novel antimicrobial agents, underscores the exigency of redeploying existing antimicrobial agents in innovative ways. One therapeutic approach that was heavily studied in the 1980s but abandoned over time is dual beta-lactam therapy. This article reviews the evidence for combination beta-lactam therapy. Overall, in vitro, animal and clinical data are positive and suggest that beta-lactam combinations produce a synergistic effect against Gram-negative pathogens that rivals that of beta-lactam-aminoglycoside or beta-lactam-fluoroquinolone combination therapy. Although the precise mechanism of improved activity is not completely understood, it is likely attributable to an enhanced affinity to the diverse penicillin-binding proteins found among Gram negatives. The collective data indicate that dual beta-lactam therapy should be revisited for serious Gram-negative infections, especially in light of the near availability of potent beta-lactamase inhibitors, which neutralize the effect of problematic beta-lactamases. PMID:25308565

Rahme, Christine; Butterfield, Jill M; Nicasio, Anthony M; Lodise, Thomas P

2014-12-01

433

Major transitions in human evolution revisited: A tribute to ancient DNA.  

PubMed

The origin and diversification of modern humans have been characterized by major evolutionary transitions and demographic changes. Patterns of genetic variation within modern populations can help with reconstructing this ?200 thousand year-long population history. However, by combining this information with genomic data from ancient remains, one can now directly access our evolutionary past and reveal our population history in much greater detail. This review outlines the main recent achievements in ancient DNA research and illustrates how the field recently moved from the polymerase chain reaction (PCR) amplification of short mitochondrial fragments to whole-genome sequencing and thereby revisited our own history. Ancient DNA research has revealed the routes that our ancestors took when colonizing the planet, whom they admixed with, how they domesticated plant and animal species, how they genetically responded to changes in lifestyle, and also, which pathogens decimated their populations. These approaches promise to soon solve many pending controversies about our own origins that are indecipherable from modern patterns of genetic variation alone, and therefore provide an extremely powerful toolkit for a new generation of molecular anthropologists. PMID:25532800

Ermini, Luca; Der Sarkissian, Clio; Willerslev, Eske; Orlando, Ludovic

2015-02-01

434

The Park Grass Experiment and next-generation approaches: local adaptation of sweet vernal grass revisited.  

PubMed

Long-term ecological experiments provide unique opportunities to observe the effects of natural selection. The Park Grass Experiment at Rothamsted Experiment Station in Hertfordshire, UK, is the longest running ecological experiment that incorporates fertilization treatments and has been ongoing since 1856. In the 1970s, local adaptation was observed in the grass Anthoxanthum odoratum to the elevated soil aluminium levels of the fertilized plots. Gould et al. () have utilized this system to reevaluate the extent of local adaptation, first documented nearly 45 years ago (Snaydon ), and to use emerging molecular approaches to identify candidate genes for the adaptation. From their work, they identify several plausible candidate loci for aluminium tolerance. This work shows the power of long-term field-based trials in a scientific age concentrated on rapidly emerging molecular techniques often utilized in short, narrowly focused laboratory or controlled environment experiments. The current study clearly illustrates the benefits gained by combining these molecular approaches within long-term monitoring experiments that can be regularly revisited in a changing world and used to address questions on evolutionary scales. PMID:25532867

von Wettberg, Eric J B; Vance, Wendy; Rowland, Diane L

2014-12-01

435

Revisiting XENON100's constraints (and signals?) for low-mass dark matter  

SciTech Connect

Although observations made with the CoGeNT and CDMS experiments have been interpreted as possible signals of low-mass ( ? 7–10 GeV) dark matter particles, constraints from the XENON100 collaboration appear to be incompatible with this hypothesis, at least at face value. In this paper, we revisit XENON100's constraint on dark matter in this mass range, and consider how various uncertainties and assumptions made might alter this conclusion. We also note that while XENON100's two nuclear recoil candidates each exhibit very low ratios of ionization-to-scintillation signals, making them difficult to attribute to known electronic or neutron backgrounds, they are consistent with originating from dark matter particles in the mass range favored by CoGeNT and CDMS. We argue that with lower, but not implausible, values for the relative scintillation efficiency of liquid xenon (L{sub eff}), and the suppression of the scintillation signal in liquid xenon at XENON100's electric field (S{sub nr}), these two events could consistently arise from dark matter particles with a mass and cross section in the range favored by CoGeNT and CDMS. If this interpretation is correct, we predict that the LUX experiment, with a significantly higher light yield than XENON100, should observe dark matter induced events at an observable rate of ? 3–24 per month.

Hooper, Dan, E-mail: dhooper@fnal.gov [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

2013-09-01

436

Gray and Green Revisited: A Multidisciplinary Perspective of Gardens, Gardening, and the Aging Process  

PubMed Central

Over fourteen years ago, the concept of “gray and green” was first introduced by Wright and Lund (2000) to represent a new awareness and a call for increased scholarship at the intersection of environmental issues and the aging process. This review paper revisits that concept with a fresh perspective on the specific role of gardens and gardening in the aging experience. As example, gardening is one of the most popular home-based leisure activities in the US and represents an important activity in the lives of older adults in a variety of residential settings. Yet, there has been a lack of any comprehensive and multidisciplinary (science and humanities) examination of the nexus between gardening and the aging experience, and in particular with research connections to stewardship and caring. In this paper, we review contemporary articles demonstrating the multidisciplinarity of gardening and the aging process. First, we will focus on the beneficial psychological effects resulting from the cultivation of caring, including personal contentment and artistic expression. Second, we will focus on stewardship and how gardening increases health, community awareness, and a connection to future generations. On the surface, this may demonstrate a separation between the humanities and science, but we will clarify a symbiotic relationship between the two disciplines in our conclusion. PMID:24734179

Wright, Scott D.; Wadsworth, Amy Maida

2014-01-01

437

FUV Spectra of Evolved Late-K and M Stars: Mass Loss Revisited and Stellar Activity  

NASA Technical Reports Server (NTRS)

This is the final report for the FUSE Cycle 1 program A100: FUV Spectra of Evolved Late-K and M Stars: Mass Loss revisited and Stellar Activity. Targets alpha TrA (K3 II) and gamma Cru (M3 III) were originally assigned 25 ksec each, to be observed in the medium aperture. Once the in-flight performance and telescope alignment problems were known, the observations were reprogrammed to optimized the scientific return of the program. Alpha TrA was scheduled for 25 ksec observations in both the medium and large apertures. The principle aim of this program was to measure the stellar FUV line and continuum emission, in order to estimate the photoionization radiation field and to determine the level of stellar activity through the fluxes in the collisionally excited high temperature diagnostics: C III 977Angstroms and O VI 1032,1038Angstrom doublet. The medium aperture observations were obtained successfully while the large aperture observations were thought by Johns Hopkins University (JHU)to be lost to satellite problems. There was insufficient signal-to- noise in the medium aperture short wavelength Sic channels to do quantitative science.

Harper, Graham M.

2002-01-01

438

The CATH classification revisited—architectures reviewed and new ways to characterize structural divergence in superfamilies  

PubMed Central

The latest version of CATH (class, architecture, topology, homology) (version 3.2), released in July 2008 (http://www.cathdb.info), contains 1 14 215 domains, 2178 Homologous superfamilies and 1110 fold groups. We have assigned 20 330 new domains, 87 new homologous superfamilies and 26 new folds since CATH release version 3.1. A total of 28 064 new domains have been assigned since our NAR 2007 database publication (CATH version 3.0). The CATH website has been completely redesigned and includes more comprehensive documentation. We have revisited the CATH architecture level as part of the development of a ‘Protein Chart’ and present information on the population of each architecture. The CATHEDRAL structure comparison algorithm has been improved and used to characterize structural diversity in CATH superfamilies and structural overlaps between superfamilies. Although the majority of superfamilies in CATH are not structurally diverse and do not overlap significantly with other superfamilies, ?4% of superfamilies are very diverse and these are the superfamilies that are most highly populated in both the PDB and in the genomes. Information on the degree of structural diversity in each superfamily and structural overlaps between superfamilies can now be downloaded from the CATH website. PMID:18996897

Cuff, Alison L.; Sillitoe, Ian; Lewis, Tony; Redfern, Oliver C.; Garratt, Richard; Thornton, Janet; Orengo, Christine A.

2009-01-01

439

Revisiting the Left-Wing Response to Sociobiology: The Case of Finland in a European Context.  

PubMed

This article revisits the left-wing response to sociobiology in the 1970s and 1980s by examining the sociobiology debate in Finland in a larger European context. It argues that the Finnish academic left's response to sociobiology represents a "third way" alongside the purely negative, often Marxist denial of biology's relevance, which characterized the left's response to sociobiology in many European countries such as Hungary and Sweden, and alongside the disregard that sociobiology confronted in most parts of Eastern Europe, as well as in Germany. In the context of the last great political conflict of the Cold War in Europe, the controversy over the American "Euromissiles" (Pershing II and Tomahawk) in 1979-1983, the Finnish academic left challenged the allegedly fatalistic sociobiological aggression and war theories with an alternative biological language, turning the increasing enthusiasm over evolutionary ideas into a pacifist cause. Using leftist and pacifist forums to inform citizens and politicians of such biologically evolved human characteristics as mutual care and sociability, the Finnish critics of sociobiology wished to boost the public spirit, and to rationalize the pacifist ideal of the European-wide popular movement against nuclear weapons and militarism. As a result, the academic leftists in Finland revived the early twentieth-century tradition of "peace biology." A proper understanding of this development calls for an analysis that acknowledges Finland's special geopolitical and cultural position in the Cold War world between East and West. PMID:24990454

Lepistö, Antti

2014-07-01

440

Revisiting the Calculation of I/V Profiles in Molecular Junctions Using the Uncertainty Principle.  

PubMed

Ortiz and Seminario (J. Chem. Phys. 2007, 127, 111106/1-3) proposed some years ago a simple and direct approach to obtain I/V profiles from the combination of ab initio equilibrium electronic structure calculations and the uncertainty principle as an alternative or complementary tool to more sophisticated nonequilibrium Green's functions methods. In this work, we revisit the fundamentals of this approach and reformulate accordingly the expression of the electric current. By analogy to the spontaneous electron decay process in electron transitions, in our revision, the current is calculated upon the relaxing process from the "polarized" state induced by the external electric field to the electronic ground state. The electric current is obtained from the total charge transferred through the molecule and the corresponding electronic energy relaxation. The electric current expression proposed is more general compared with the previous expression employed by Ortiz and Seminario, where the charge variation must be tested among different slabs of atoms at the contact. This new approach has been tested on benzene-1,4-dithiolate attached to different gold clusters that represent the contact with the electrodes. Analysis of the total electron deformation density induced by the external electric voltage and properties associated with the electron deformation orbitals supports the conclusions obtained from the I/V profiles. PMID:24689867

Ramos-Berdullas, Nicolás; Mandado, Marcos

2014-04-17

441

Stereospecificity of Oligonucleotide Interactions Revisited: No Evidence for Heterochiral Hybridization and Ribozyme/DNAzyme Activity.  

PubMed

A major challenge for the application of RNA- or DNA-oligonucleotides in biotechnology and molecular medicine is their susceptibility to abundant nucleases. One intriguing possibility to tackle this problem is the use of mirror-image (l-)oligonucleotides. For aptamers, this concept has successfully been applied to even develop therapeutic agents, so-called Spiegelmers. However, for technologies depending on RNA/RNA or RNA/DNA hybridization, like antisense or RNA interference, it has not been possible to use mirror-image oligonucleotides because Watson-Crick base pairing of complementary strands is (thought to be) stereospecific. Many scientists consider this a general principle if not a dogma. A recent publication proposing heterochiral Watson-Crick base pairing and sequence-specific hydrolysis of natural RNA by mirror-image ribozymes or DNAzymes (and vice versa) prompted us to systematically revisit the stereospecificity of oligonucleotides hybridization and catalytic activity. Using hyperchromicity measurements we demonstrate that hybridization only occurs among homochiral anti-parallel complementary oligonucleotide strands. As expected, achiral PNA hybridizes to RNA and DNA irrespective of their chirality. In functional assays we could not confirm an alleged heterochiral hydrolytic activity of ribozymes or DNAzymes. Our results confirm a strict stereospecificity of oligonucleotide hybridization and clearly argue against the possibility to use mirror-image oligonucleotides for gene silencing or antisense applications. PMID:25679211

Hoehlig, Kai; Bethge, Lucas; Klussmann, Sven

2015-01-01

442

A fussy revisitation of antiprotons as a tool for Dark Matter searches  

E-print Network

Antiprotons are regarded as a powerful probe for Dark Matter (DM) indirect detection and indeed current data from PAMELA have been shown to lead to stringent constraints. However, in order to exploit their constraining/discovery power properly and especially in anticipation of the exquisite accuracy of upcoming data from AMS, great attention must be put into effects (linked to their propagation in the Galaxy) which may be perceived as subleasing but actually prove to be quite relevant. We revisit the computation of the astrophysical background and of the DM antiproton fluxes fully including the effects of: diffusive reacceleration, energy losses including tertiary component and solar modulation (in a force field approximation). We show that their inclusion can somewhat modify the current bounds, even at large DM masses, and that a wrong interpretation of the data may arise if they are not taken into account. The numerical results for the astrophysical background are provided in terms of fit functions; the results for Dark Matter are incorporated in the new release of the PPPC4DMID.

Mathieu Boudaud; Marco Cirelli; Gaëlle Giesen; Pierre Salati

2014-12-18

443

Revisiting Low Energy Deuteron Production of [18F] Fluoride and Fluorine for PET  

SciTech Connect

Fluorine-18 is currently the most widely used radioisotope in PET imaging. While much attention has been paid in recent years to production methods from 18O(p,n)18F, the current work revisits production techniques using non-enriched neon targets and the 20Ne(d,{alpha})18F reaction. While this reaction was originally pursued, and ultimately replaced by the higher yielding 18O reactions, there is an opportunity using high current low-energy deuteron accelerators and the inherent simplicity of gas targetry to provide viable alternatives to the costly 18O water target systems. 18F production systems have been developed for the gas-phase 20Ne(d,{alpha})18F reaction with deuterons from a 3MV NEC 9SDH-2 electrostatic tandem accelerator. High power target systems allowing for irradiation in excess of 100uA provided [18F]F2 yields to 86% of the theoretical maximum, and [18F]F- yields with a wash-off system of 80% of the maximum.

Barnhart, T.E.; Nickles, R.J. [Medical Physics Department, University of Wisconsin, Madison, Wisconsin, 1500 North Highland Ave., Waisman Center, Madison, WI 53705 (United States); Roberts, A.D. [Medical Physics Department, University of Wisconsin, Madison, Wisconsin, 1500 North Highland Ave., Waisman Center, Madison, WI 53705 (United States); Psychiatry Department, University of Wisconsin, Madison, Wisconsin, 1500 North Highland Ave., Waisman Center, Madison, WI 53705 (United States)

2003-08-26

444

The origin of dust in galaxies revisited: the mechanism determining dust content  

E-print Network

The origin of cosmic dust is a fundamental issue in planetary science. This paper revisits the origin of dust in galaxies, in particular, in the Milky Way, by using a chemical evolution model of a galaxy composed of stars, interstellar medium, metals (elements heavier than helium), and dust. We start from a review of time-evolutionary equations of the four components, and then, we present simple recipes for the stellar remnant mass and yields of metal and dust based on models of stellar nucleosynthesis and dust formation. After calibrating some model parameters with the data from the solar neighborhood, we have confirmed a shortage of the stellar dust production rate relative to the dust destruction rate by supernovae if the destruction efficiency suggested by theoretical works is correct. If the dust mass growth by material accretion in molecular clouds is active, the observed dust amount in the solar neighborhood is reproduced. We present a clear analytic explanation of the mechanism for determining dust co...

Inoue, Akio K

2012-01-01

445

The origin of dust in galaxies revisited: the mechanism determining dust content  

NASA Astrophysics Data System (ADS)

The origin of cosmic dust is a fundamental issue in planetary science. This paper revisits the origin of dust in galaxies, in particular, in the Milky Way, by using a chemical evolution model of a galaxy composed of stars, interstellar medium, metals (elements heavier than helium), and dust. We start from a review of time-evolutionary equations of the four components, and then, we present simple recipes for the stellar remnant mass and yields of metal and dust based on models of stellar nucleosynthesis and dust formation. After calibrating some model parameters with the data from the solar neighborhood, we have confirmed a shortage of the stellar-dust-production rate relative to the dust-destruction rate by supernovae if the destruction efficiency suggested by theoretical works is correct. If the dust-mass growth by material accretion in molecular clouds is active, the observed dust amount in the solar neighborhood is reproduced. We present a clear analytic explanation of the mechanism for determining dust content in galaxies after the activation of accretion growth: a balance between accretion growth and supernova destruction. Thus, the dust content is independent of the uncertainty of the stellar dust yield after the growth activation. The timing of the activation is determined by a critical metal mass fraction which depends on the growth and destruction efficiencies. The solar system formation seems to have occurred well after the activation and plenty of dust would have existed in the proto-solar nebula.

Inoue, A. K.

2011-10-01

446

Corona discharges and their effect on lightning attachment revisited: Upward leader initiation and downward leader interception  

NASA Astrophysics Data System (ADS)

Previous studies have suggested the possibility of using glow corona discharges to control the frequency of lightning flashes to grounded objects. In order to revisit the theoretical basis of this proposal, the self-consistent leader inception and propagation model - SLIM - is used together with a two-dimensional glow corona drift model. The analysis is performed to quantify the effect of glow corona generated at the tip of ground-based objects on the initiation and propagation of upward positive connecting leaders under the influence of downward lightning leaders. It is found that the presence of glow corona does not influence the performance of Franklin lightning rods shorter than 15 m, while it slightly reduces the lateral distance of rods up to 60 m tall by a maximum of 10%. Furthermore, the results indicate that it is not possible to suppress the initiation of upward connecting leaders by means of glow corona. It is found instead that unconventional lightning protection systems based on the generation of glow corona attract downward lightning flashes in a similar way as a standard lightning rod with the same height.

Becerra, Marley

2014-11-01

447

Iron deficiency in the elderly population, revisited in the hepcidin era  

PubMed Central

Iron deficiency (ID) is relatively common among the elderly population, contributing substantially to the high prevalence of anemia observed in the last decades of life, which in turn has important implications both on quality of life and on survival. In elderly subjects, ID is often multifactorial, i.e., due to multiple concurring causes, including inadequate dietary intake or absorption, occult bleeding, medications. Moreover, because of the typical multimorbidity of aged people, other conditions leading to anemia frequently coexist and make diagnosis of ID particularly challenging. Treatment of ID is also problematic in elderly, since response to oral iron is often slow, with a substantial fraction of patients showing refractoriness and requiring cumbersome intravenous administration. In the last decade, the discovery of the iron regulatory hormone hepcidin has revolutionized our understanding of iron pathophysiology. In this review, we revisit ID among elderly people in the light of the impressive recent advances on knowledge of iron regulation, and discuss how hepcidin may help in diagnosis and treatment of this common clinical condition. PMID:24795637

Busti, Fabiana; Campostrini, Natascia; Martinelli, Nicola; Girelli, Domenico

2014-01-01

448

Revisiting the two first instabilities of the flow in an annular rotor-stator cavity  

NASA Astrophysics Data System (ADS)

The stability of the flow enclosed between a stationary and a rotating disk with a central hub is revisited by experimental visualizations and direct numerical simulations in the case of unmerged boundary layers. The first instability appears as circular rolls, denoted by CRs (type 2 instability), which propagate along the stator before vanishing in the vicinity of the hub. The calculations highlight the convective nature of these rolls, which is in agreement with previous experimental results (P. Gauthier, P. Gondret, and M. Rabaud, J. Fluid Mech. 386, 105 (1999)). It proves in particular that the CR instability observed in the experiment under permanent conditions is noise sustained. Above a second threshold, spiral rolls, denoted SR1 (type 1 instability), appear at the periphery of the cavity and can coexist with the circular rolls. The DNS shows that they appear through a supercritical Hopf bifurcation. The SR1 patterns appear to be very close to those emitted by the corner vortices obtained by Lopez and Weidman [J. Fluid Mech. 326, 373 (1996)] during the spin-down of a rotating disk in a fixed cylinder.

Poncet, Sébastien; Serre, Éric; Le Gal, Patrice

2009-06-01

449

Revisiting the relationship between adaptive smoothing and anisotropic diffusion with modified filters.  

PubMed

Anisotropic diffusion has been known to be closely related to adaptive smoothing and discretized in a similar manner. This paper revisits a fundamental relationship between two approaches. It is shown that adaptive smoothing and anisotropic diffusion have different theoretical backgrounds by exploring their characteristics with the perspective of normalization, evolution step size, and energy flow. Based on this principle, adaptive smoothing is derived from a second order partial differential equation (PDE), not a conventional anisotropic diffusion, via the coupling of Fick's law with a generalized continuity equation where a "source" or "sink" exists, which has not been extensively exploited. We show that the source or sink is closely related to the asymmetry of energy flow as well as the normalization term of adaptive smoothing. It enables us to analyze behaviors of adaptive smoothing, such as the maximum principle and stability with a perspective of a PDE. Ultimately, this relationship provides new insights into application-specific filtering algorithm design. By modeling the source or sink in the PDE, we introduce two specific diffusion filters, the robust anisotropic diffusion and the robust coherence enhancing diffusion, as novel instantiations which are more robust against the outliers than the conventional filters. PMID:23193236

Ham, Bumsub; Min, Dongbo; Sohn, Kwanghoon

2013-03-01

450

REVISITING THE FIRST GALAXIES: THE EFFECTS OF POPULATION III STARS ON THEIR HOST GALAXIES  

SciTech Connect

We revisit the formation and evolution of the first galaxies using new hydrodynamic cosmological simulations with the adaptive refinement tree code. Our simulations feature a recently developed model for H{sub 2} formation and dissociation, and a star formation recipe that is based on molecular rather than atomic gas. Here, we develop and implement a recipe for the formation of metal-free Population III (Pop III) stars in galaxy-scale simulations that resolve primordial clouds with sufficiently high density. We base our recipe on the results of prior zoom-in simulations that resolved the protostellar collapse in pre-galactic objects. We find the epoch during which Pop III stars dominated the energy and metal budget of the first galaxies to be short-lived. Galaxies that host Pop III stars do not retain dynamical signatures of their thermal and radiative feedback for more than 10{sup 8} years after the lives of the stars end in pair-instability supernovae, even when we consider the maximum reasonable efficiency of the feedback. Though metals ejected by the supernovae can travel well beyond the virial radius of the host galaxy, they typically begin to fall back quickly, and do not enrich a large fraction of the intergalactic medium. Galaxies with a total mass in excess of 3 Multiplication-Sign 10{sup 6} M{sub Sun} re-accrete most of their baryons and transition to metal-enriched Pop II star formation.

Muratov, Alexander L.; Gnedin, Oleg Y.; Zemp, Marcel [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Gnedin, Nickolay Y., E-mail: muratov@umich.edu [Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

2013-08-01

451

'The Ethiopian famine' revisited: band aid and the antipolitics of celebrity humanitarian action.  

PubMed

In many ways the Ethiopian famine of 1983-85 has served as a watershed with respect to humanitarian action. One of its lasting legacies has been the emergence of Band Aid and the subsequent increase in celebrity humanitarianism. A revisiting of the events of 1983-85 occurred in 2010 during a dispute in which it was alleged that a portion of the donations of Band Aid were spent on arms purchases. This paper takes this controversy as its starting point. It goes on to use the theoretical reflections of Giorgio Agamben to consider the dynamics that unfolded during the Ethiopian famine of 1983-85 and to analyse the underlying conceptualisation behind the emergence of Band Aid-type celebrity humanitarianism. The paper concludes with some wider thoughts on how the in essence antipolitical agenda of celebrity humanitarian action is transported into the everyday understanding of 'African disaster', resulting ultimately in the perpetuation of hegemonic control by the global North. PMID:23067379

Müller, Tanja R

2013-01-01

452

Inverse Neutrino-less Double Beta Decay Revisited: Neutrinos, Higgs Triplets and a Muon Collider  

E-print Network

We revisit the process of inverse neutrino-less double beta decay (e e -> W W) at future linear colliders. The cases of Majorana neutrino and Higgs triplet exchange are considered. We also discuss the processes e mu -> W W and mu mu -> W W, which are motivated by the possibility of muon colliders. For heavy neutrino exchange and center-of-mass energies larger than 1 TeV, we show that masses up to 10^6 (10^5) GeV could be probed for e-e and e-mu machines, respectively. The stringent limits for mixing of heavy neutrinos with muons render mu mu -> W W less promising, even though this process is not constrained by limits from neutrino-less double beta decay. If Higgs triplets are responsible for inverse neutrino-less double beta decay, observable signals are only possible if a very narrow resonance is met. We also consider unitarity aspects of the process in case both Higgs triplets and neutrinos are exchanged. An exact see-saw relation connecting low energy data with heavy neutrino and triplet parameters is found.

Werner Rodejohann

2010-05-17

453

Adaptive Control for Linear Uncertain Systems with Unmodeled Dynamics Revisited via Optimal Control Modification  

NASA Technical Reports Server (NTRS)

This paper presents the optimal control modification for linear uncertain plants. The Lyapunov analysis shows that the modification parameter has a limiting value depending on the nature of the uncertainty. The optimal control modification exhibits a linear asymptotic property that enables it to be analyzed in a linear time invariant framework for linear uncertain plants. The linear asymptotic property shows that the closed-loop plants in the limit possess a scaled input-output mapping. Using this property, we can derive an analytical closed-loop transfer function in the limit as the adaptive gain tends to infinity. The paper revisits the Rohrs counterexample problem that illustrates the nature of non-robustness of model-reference adaptive control in the presence of unmodeled dynamics. An analytical approach is developed to compute exactly the modification parameter for the optimal control modification that stabilizes the plant in the Rohrs counterexample. The linear asymptotic property is also used to address output feedback adaptive control for non-minimum phase plants with a relative degree 1.

Nguyen, Nhan

2013-01-01

454

EVIDENCE FOR TWO DISTINCT STELLAR INITIAL MASS FUNCTIONS: REVISITING THE EFFECTS OF CLUSTER DYNAMICAL EVOLUTION  

SciTech Connect

We measure the velocity dispersions of six galactic globular clusters using spatially integrated spectra, to test for the effects of internal dynamical evolution in the stellar mass-to-light ratios, Y{sub *}, of star clusters. In particular, we revisit whether the low values of Y{sub *} that we found in our previous study, from which we concluded that there are at least two population of stellar clusters with distinct stellar initial mass functions, are artificially depressed by relaxation driven mass loss. The combination of our previous sample of five old clusters and these six now provide an order of magnitude range in cluster mass with which to explore this issue. We find no relationship between cluster mass, or relaxation time, and Y{sub *}. Because relaxation is mass dependent, we conclude that the values of Y{sub *} for these clusters are not strongly affected by dynamical effects, and so confirm the presence of the population of clusters with low Y{sub *}.

Zaritsky, Dennis [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Colucci, Janet E.; Bernstein, Rebecca A. [Department of Astronomy and Astrophysics, 1156 High Street, UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Pessev, Peter M. [Gemini South Observatory, c/o AURA Inc., Casilla 603, La Serena (Chile); Chandar, Rupali, E-mail: dzaritsky@as.arizona.edu [Department of Physics and Astronomy, The University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States)

2013-06-20

455

Re-Visiting of Plentiful Food Sources and Food Search Strategies in Desert Ants  

PubMed Central

North African desert ants, Cataglyphis fortis, are established model organisms in animal navigation research. Cataglyphis re-visit plentiful feeding sites, but their decision to return to a feeder and the organization of food searches has been little studied. Here we provide a review of recent advances regarding this topic. At least two parameters determine the ants’ assessment of site quality, namely, amount of food available and reliability of food encounter on subsequent visits. The amount of food appears to be judged by the concentration of items at the food uptake site. Initially the amount of food in a feeder dominates the foragers’ decision to return, whereas learning about reliability takes precedence in the course of a few visits. The location of a worthwhile site is determined by the animals’ path integration system. In particular, the distance of the feeding site is memorized as the arithmetic average of the distances covered during the previous outbound and homebound journeys. Feeding sites that are small and inconspicuous cannot be approached directly with sufficient certainty, due to inevitable inaccuracies of the path integrator. Instead, desert ants steer downwind of the goal to encounter the odor plume emanating from the food and they follow this plume to the feeder. The angle steered downwind reflects the animals’ maximal navigation error and is adjusted according to experience. In summary, food searches of desert ants provide an unexpected wealth of features that may advance our understanding of search, navigation, and decision strategies. There are several aspects that warrant further scrutiny. PMID:22783163

Wolf, Harald; Wittlinger, Matthias; Bolek, Siegfried

2012-01-01

456

Revisiting polymer surface diffusion in the extreme case of strong adsorption.  

PubMed

Revisiting polymer surface adsorption with a level of quantification not possible at the time of earlier seminal contributions to this field, we employ fluorescence microscopy to quantify the in-plane diffusion of end-labeled polystyrene adsorbed onto quartz and mica from cyclohexane solution, mostly at 25 °C. Care is taken to prohibit a surface-hopping mechanism, and the experimental techniques are adapted to measurements that persist for up to a few days. The main conclusion is that we fail to observe a single Fickian diffusion coefficient: instead, diffusion displays a broad multicomponent spectrum, indicating that the heterogeneity of surface diffusion fails to average out even over these long times and over distances (?600 nm, the diameter of a diffraction-limited spot) greatly exceeding the size of the polymer molecules. This holds generally when we vary the molecular weight, the surface roughness, and the temperature. It quantifies the long-believed scenario that strongly adsorbed polymer layers (monomer-surface interaction of more than 1kBT) intrinsically present diverse surface conformations that present heterogeneous environments to one another as they diffuse. Bearing in mind that in spite of adsorption from dilute solution the interfacial polymer concentration is high, ramifications of these findings are relevant to the interfacial mobility of polymer glasses, melts, and nanocomposites. PMID:25423039

Yu, Changqian; Granick, Steve

2014-12-01

457

The uranyl ion revisited: the electric field gradient at U as a probe of environmental effects  

NASA Astrophysics Data System (ADS)

The experimental electric field gradient (EFG) at the U nucleus in uranyl is positive. It has been pointed out by Pyykkö that this could be a signature of a hole in the 6p shell induced by the strong bonding to the axial O atoms. We have revisited this issue with the help of relativistic density functional calculations, including accurate ZORA-4 calculations of the EFG. We confirm the existence of a 6p hole, with a positive contribution to the EFG, but we still find the EFG in the free uranyl ion to be negative due to the non-spherical electron distribution in the valence 5f shell caused by the bonding to the oxygens. A positive EFG only results in our calculations from the effect of the crystal environment of the uranyl ion, i.e. the coordination of three nitrate groups in the equatorial plane. Again the extended nature of 6p plays a key role, with an important positive contribution to the EFG coming from 6p tails in the high-lying electron pair orbitals of the closed shell nitrate ligands due to the orthogonality requirement. A further contribution comes from electron donation by the nitrate groups into the U 5? and 6d? orbitals which both have their lobes in the equatorial plane. Our findings highlight the sensitivity of the EFG to the environment, through effects on the upper valence electronic structure.

Belanzoni, Paola; Baerends, Evert Jan; van Lenthe, Erik

458

A fussy revisitation of antiprotons as a tool for Dark Matter searches  

E-print Network

Antiprotons are regarded as a powerful probe for Dark Matter (DM) indirect detection and indeed current data from PAMELA have been shown to lead to stringent constraints. However, in order to exploit their constraining/discovery power properly and especially in anticipation of the exquisite accuracy of upcoming data from AMS, great attention must be put into effects (linked to their propagation in the Galaxy) which may be perceived as subleasing but actually prove to be quite relevant. We revisit the computation of the astrophysical background and of the DM antiproton fluxes fully including the effects of: diffusive reacceleration, energy losses including tertiary component and solar modulation (in a force field approximation). We show that their inclusion can somewhat modify the current bounds, even at large DM masses, and that a wrong interpretation of the data may arise if they are not taken into account. The numerical results for the astrophysical background are provided in terms of fit functions; the results for Dark Matter are incorporated in the new release of the PPPC4DMID.

Mathieu Boudaud; Marco Cirelli; Gaëlle Giesen; Pierre Salati

2015-01-19

459

TYPE II-P SUPERNOVAE AS STANDARD CANDLES: THE SDSS-II SAMPLE REVISITED  

SciTech Connect

We revisit the observed correlation between the H{beta} and Fe II velocities for Type II-P supernovae (SNe II-P) using 28 optical spectra of 13 SNe II-P and demonstrate that it is well modeled by a linear relation with a dispersion of about 300 km s{sup -1}. Using this correlation, we re-analyze the publicly available sample of SNe II-P compiled by D'Andrea et al. and find a Hubble diagram with an intrinsic scatter of 11% in distance, which is nearly as tight as that measured before their sample is added to the existing set. The larger scatter reported in their work is found to be systematic, and most of it can be alleviated by measuring the H{beta} rather than Fe II velocities, due to the low signal-to-noise ratios and early epochs at which many of the optical spectra were obtained. Their sample, while supporting the mounting evidence that SNe II-P are good cosmic rulers, is biased toward intrinsically brighter objects and is not a suitable set to improve upon SN II-P correlation parameters. This will await a dedicated survey.

Poznanski, Dovi; Nugent, Peter E. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Filippenko, Alexei V., E-mail: dovi@berkeley.ed [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

2010-10-01

460

Piecing the puzzle together: a revisit to transcript reconstruction problem in RNA-seq  

PubMed Central

The advancement of RNA sequencing (RNA-seq) has provided an unprecedented opportunity to assess both the diversity and quantity of transcript isoforms in an mRNA transcriptome. In this paper, we revisit the computational problem of transcript reconstruction and quantification. Unlike existing methods which focus on how to explain the exons and splice variants detected by the reads with a set of isoforms, we aim at reconstructing transcripts by piecing the reads into individual effective transcript copies. Simultaneously, the quantity of each isoform is explicitly measured by the number of assembled effective copies, instead of estimated solely based on the collective read count. We have developed a novel method named Astroid that solves the problem of effective copy reconstruction on the basis of a flow network. The RNA-seq reads are represented as vertices in the flow network and are connected by weighted edges that evaluate the likelihood of two reads originating from the same effective copy. A maximum likelihood set of transcript copies is then reconstructed by solving a minimum-cost flow problem on the flow network. Simulation studies on the human transcriptome have demonstrated the superior sensitivity and specificity of Astroid in transcript reconstruction as well as improved accuracy in transcript quantification over several existing approaches. The application of Astroid on two real RNA-seq datasets has further demonstrated its accuracy through high correlation between the estimated isoform abundance and the qRT-PCR validations. PMID:25252653

2014-01-01

461

A matching problem revisited for stability analysis of resistive wall modes in flowing plasmas  

SciTech Connect

The classical matching problem for magnetohydrodynamic stability analysis is revisited to study effects of the plasma flow on the resistive wall modes (RWMs). The Newcomb equation, which describes the marginal states and governs the regions except for the resonant surface, is generalized to analyze the stability of flowing plasmas. When there exists no flow, the singular point of the Newcomb equation and the resonant surface degenerate into the rational surface. The location of the rational surface is prescribed by the equilibrium, hence the inner layer, which must contain the resonant surface, can be set a priori. When the flow exists, the singular point of the Newcomb equation splits in two due to the Doppler shift. Additionally, the resonant surface deviates from the singular points and the rational surface if the resonant eigenmode has a real frequency. Since the location of the resonant surface depends on the unknown real frequency, it can be determined only a posteriori. Hence the classical asymptotic matching method cannot be applied. This paper shows that a new matching method that generalizes the asymptotic one to use the inner layer with finite width works well for the stability analysis of flowing plasmas. If the real frequency is limited in a certain range such as the RWM case, the resonance occurs somewhere in the finite region around the singular points, hence the inner layer with finite width can capture the resonant surface.

Shiraishi, J.; Tokuda, S.; Aiba, N. [Japan Atomic Energy Agency, 801-1 Mukouyama, Naka-shi, Ibaraki-ken 311-0193 (Japan)

2010-01-15

462

Lewis' law revisited: the role of anisotropy in size-topology correlations  

NASA Astrophysics Data System (ADS)

Since F T Lewis' pioneering work in the 1920s, a linear correlation between the average in-plane area of domains in a two-dimensional (2D) cellular structure and the number of neighbors of the domains has been empirically proposed, with many supporting and dissenting findings in the ensuing decades. Revisiting Lewis' original experiment, we take a larger set of more detailed data on the cells in the epidermal layer of Cucumis, and analyze the data in the light of recent results on size-topology correlations. We find that the correlation between the number-of-neighbor distribution (topology) and the area distribution is altered over that of many other 2D cellular systems (such as foams or disc packings), and that the systematic deviation can be explained by the anisotropic shape of the Cucumis cells. We develop a novel theory of size-topology correlation taking into account the characteristic aspect ratio of the cells within the framework of a granocentric model, and show that both Lewis' and our experimental data is consistent with the theory. In contrast to the granocentric model for isotropic domains, the new theory results in an approximately linear correlation consistent with Lewis' law. These statistical effects can be understood from the increased number of configurations available to a plane-filling domain system with non-isotropic elements, for the first time providing a firm explanation of why Lewis' law is valid in some systems and fails in others.

Kim, Sangwoo; Cai, Muyun; Hilgenfeldt, Sascha

2014-01-01

463

A review of "England's Wars of Religion, Revisited" edited by Charles W. A. Prior and Glenn Burgess  

E-print Network

engagement, it is likely to #23; nd only a very limited audience. Charles W. A. Prior and Glenn Burgess, eds. England?s Wars of Religion, Revisited. Farnham and Burlington: Ashgate, 2011. xiv + 335 pp. + 2 illustrations. $115.00. Review by #8;#7; #2...; . #15;#18;#5;#30;#15;#3;#11;, #5; #4;#3; #2; #6;#11; #14;#19; #11;#14; #31;. #22; e fourteen essays produced in this volume revolve around the premise made by John Morrill in 1983 that the English Civil War was the last war of religion, rather than...

Langley, Chris R.

2012-01-01

464

Revisiting the "Sleeping Giant" Metaphor: Is It Still Sleeping in the Commonwealth of Virginia, and Is It Still Really a Giant?  

ERIC Educational Resources Information Center

In order to revisit Martorella's metaphor of technology as a sleeping giant this paper analyzes data collected over multiple years in order to provide a portrait of how preservice teachers make sense of and choose (if at all) to integrate digital technologies within their internship classrooms. Findings indicate that in the Commonwealth of…

Hicks, David; van Hover, Stephanie

2014-01-01

465

Alderete, John, Paul Tupper, Stefan A. Frisch. 2012. Phonotactic learning without a priori constraints: Arabic root co-occurrence restrictions revisited. In Proceedings  

E-print Network

Alderete, John, Paul Tupper, Stefan A. Frisch. 2012. Phonotactic learning without a priori constraints: Arabic root co-occurrence restrictions revisited. In Proceedings of the 48th meeting are located. Both ci and wi are determined by the learning algorithm. Our architecture is: F(x) = ( - i wi (bi

Tupper, Paul

466

European Journal of Soil Science, December 2010, 61, 854864 doi: 10.1111/j.1365-2389.2010.01298.x Revisiting the particle-size distribution of soils  

E-print Network

European Journal of Soil Science, December 2010, 61, 854­864 doi: 10.1111/j.1365-2389.2010.01298.x Revisiting the particle-size distribution of soils: comparison of different methods and sample pre and Palaeontology, Faculty of Science, University of Zagreb, Horvatovac 102 a, 10000 Zagreb, Croatia Summary

Ahmad, Sajjad

467

Revisiting Experimental Catchment Studies in Forest Hydrology (Proceedings of a Workshop held during the XXV IUGG General Assembly in Melbourne, JuneJuly 2011) (IAHS Publ. 353, 2012).  

E-print Network

Revisiting Experimental Catchment Studies in Forest Hydrology (Proceedings of a Workshop held, 50080 Zaragoza, Spain Abstract The hydrological response of two neighbouring catchments in the central for this switching behaviour could be an increase in the hydrological connectivity within the slopes of the forested

Utrecht, Universiteit

468

"Keeping Close and Spoiling" Revisited: Exploring the Significance of "Home" for Family Relationships and Educational Trajectories in a Marginalised Estate in Urban South Wales  

ERIC Educational Resources Information Center

This paper revisits Diana Leonard's seminal paper "Keeping close and spoiling in a south Wales town", by drawing on one mother and daughter case study. Leonard focused on geographical closeness and the strategies employed by parents to keep their children living at home, rather than sending them to university. In contrast, this…

Mannay, Dawn

2013-01-01

469

Revisiting the Einstein-Bohr Dialogue Einstein and Bohr No names loom larger in the history of twentieth-century physics, and  

E-print Network

in the history of twentieth-century physics, and rightly so, Albert Einstein and Niels Bohr being the figuresRevisiting the Einstein-Bohr Dialogue Don Howard Einstein and Bohr ­ No names loom larger identified complementarity as the chief novelty in the quantum description of nature, Einstein for having

Howard, Don

470

Developing the individual, the worker, the citizen: the aims of education re-visited in the information society: how can ICT help innovation  

E-print Network

-visited in the information society: how can ICT help innovation SCIENTER 1 DEVELOPING THE INDIVIDUAL, THE WORKER, THE CITIZEN. THE AIMS OF EDUCATION RE-VISITED IN THE INFORMATION SOCIETY: HOW CAN ICT HELP INNOVATION? By Claudio Dondi ABSTRACT This paper addresses the issue of how ICT are producing an impact on education and training

Paris-Sud XI, Université de

471

Aluminium distribution in ZSM-5 revisited: The role of Al-Al interactions  

SciTech Connect

We present a theoretical study of the distribution of Al atoms in zeolite ZSM-5 with Si/Al=47, where we focus on the role of Al-Al interactions rather than on the energetics of Al/Si substitutions at individual sites. Using interatomic potential methods, we evaluate the energies of the full set of symmetrically independent configurations of Al siting in a Si{sub 94}Al{sub 2}O{sub 192} cell. The equilibrium Al distribution is determined by the interplay of two factors: the energetics of the Al/Si substitution at an individual site, which tends to populate particular T sites (e.g., the T14 site), and the Al-Al interaction, which at this Si/Al maximises Al-Al distances in general agreement with Dempsey's rule. However, it is found that the interaction energy changes approximately as the inverse of the square of the distance between the two Al atoms, rather than the inverse of the distance expected if this were merely charge repulsion. Moreover, we find that the anisotropic nature of the framework density plays an important role in determining the magnitude of the interactions, which are not simply dependent on Al-Al distances. - Graphical abstract: Role of Al-Al interactions in high silica ZSM-5 is shown to be anisotropic in nature and not dependent solely on Coulombic interactions. Highlights: Black-Right-Pointing-Pointer Si-Al distribution in ZSM-5 is revisited, stressing the role of the Al-Al interaction. Black-Right-Pointing-Pointer Coulomb interactions are not the key factors controlling the Al siting. Black-Right-Pointing-Pointer Anisotropy of the framework is identified as a source of departure from Dempsey's rule.

Ruiz-Salvador, A. Rabdel, E-mail: rabdel@imre.oc.uh.cu [Group of Materials Developed by Design, Division of Chemistry and Technology of Materials, Institute of Materials Science and Engineering (IMRE), University of Havana, Havana 10400 (Cuba); Grau-Crespo, Ricardo; Gray, Aileen E.; Lewis, Dewi W. [Department of Chemistry, University College London, 20 Gordon Street, London, WC1H OAJ (United Kingdom)] [Department of Chemistry, University College London, 20 Gordon Street, London, WC1H OAJ (United Kingdom)

2013-02-15

472

Short-term retention of relational memory in amnesia revisited: accurate performance depends on hippocampal integrity  

PubMed Central

Traditionally, it has been proposed that the hippocampus and adjacent medial temporal lobe cortical structures are selectively critical for long-term declarative memory, which entails memory for inter-item and item-context relationships. Whether the hippocampus might also contribute to short-term retention of relational memory representations has remained controversial. In two experiments, we revisit this question by testing memory for relationships among items embedded in scenes using a standard working memory trial structure in which a sample stimulus is followed by a brief delay and the corresponding test stimulus. In each experimental block, eight trials using different exemplars of the same scene were presented. The exemplars contained the same items but with different spatial relationships among them. By repeating the pictures across trials, any potential contributions of item or scene memory to performance were minimized, and relational memory could be assessed more directly than has been done previously. When test displays were presented, participants indicated whether any of the item-location relationships had changed. Then, regardless of their responses (and whether any item did change its location), participants indicated on a forced-choice test, which item might have moved, guessing if necessary. Amnesic patients were impaired on the change detection test, and were frequently unable to specify the change after having reported correctly that a change had taken place. Comparison participants, by contrast, frequently identified the change even when they failed to report the mismatch, an outcome that speaks to the sensitivity of the change specification measure. These results confirm past reports of hippocampal contributions to short-term retention of relational memory representations, and suggest that the role of the hippocampus in memory has more to do with relational memory requirements than the length of a retention interval. PMID:24478681

Yee, Lydia T. S.; Hannula, Deborah E.; Tranel, Daniel; Cohen, Neal J.

2014-01-01

473

Disappearing Scales in Carps: Re-Visiting Kirpichnikov's Model on the Genetics of Scale Pattern Formation  

PubMed Central

The body of most fishes is fully covered by scales that typically form tight, partially overlapping rows. While some of the genes controlling the formation and growth of fish scales have been studied, very little is known about the genetic mechanisms regulating scale pattern formation. Although the existence of two genes with two pairs of alleles (S&s and N&n) regulating scale coverage in cyprinids has been predicted by Kirpichnikov and colleagues nearly eighty years ago, their identity was unknown until recently. In 2009, the ‘S’ gene was found to be a paralog of fibroblast growth factor receptor 1, fgfr1a1, while the second gene called ‘N’ has not yet been identified. We re-visited the original model of Kirpichnikov that proposed four major scale pattern types and observed a high degree of variation within the so-called scattered phenotype due to which this group was divided into two sub-types: classical mirror and irregular. We also analyzed the survival rates of offspring groups and found a distinct difference between Asian and European crosses. Whereas nude × nude crosses involving at least one parent of Asian origin or hybrid with Asian parent(s) showed the 25% early lethality predicted by Kirpichnikov (due to the lethality of the NN genotype), those with two Hungarian nude parents did not. We further extended Kirpichnikov's work by correlating changes in phenotype (scale-pattern) to the deformations of fins and losses of pharyngeal teeth. We observed phenotypic changes which were not restricted to nudes, as described by Kirpichnikov, but were also present in mirrors (and presumably in linears as well; not analyzed in detail here). We propose that the gradation of phenotypes observed within the scattered group is caused by a gradually decreasing level of signaling (a dose-dependent effect) probably due to a concerted action of multiple pathways involved in scale formation. PMID:24386179

Goh, Chin Heng; Kathiresan, Purushothaman; Németh, Sándor; Jeney, Zsigmond; Bercsényi, Miklós; Orbán, László

2013-01-01

474

Pathophysiology of autism spectrum disorders: revisiting gastrointestinal involvement and immune imbalance.  

PubMed

Autism spectrum disorders (ASD) comprise a group of neurodevelopmental abnormalities that begin in early childhood and are characterized by impairment of social communication and behavioral problems including restricted interests and repetitive behaviors. Several genes have been implicated in the pathogenesis of ASD, most of them are involved in neuronal synaptogenesis. A number of environmental factors and associated conditions such as gastrointestinal (GI) abnormalities and immune imbalance have been linked to the pathophysiology of ASD. According to the March 2012 report released by United States Centers for Disease Control and Prevention, the prevalence of ASD has sharply increased during the recent years and one out of 88 children suffers now from ASD symptoms. Although there is a strong genetic base for the disease, several associated factors could have a direct link to the pathogenesis of ASD or act as modifiers of the genes thus aggravating the initial problem. Many children suffering from ASD have GI problems such as abdominal pain, chronic diarrhea, constipation, vomiting, gastroesophageal reflux, and intestinal infections. A number of studies focusing on the intestinal mucosa, its permeability, abnormal gut development, leaky gut, and other GI problem raised many questions but studies were somehow inconclusive and an expert panel of American Academy of Pediatrics has strongly recommended further investigation in these areas. GI tract has a direct connection with the immune system and an imbalanced immune response is usually seen in ASD children. Maternal infection or autoimmune diseases have been suspected. Activation of the immune system during early development may have deleterious effect on various organs including the nervous system. In this review we revisited briefly the GI and immune system abnormalities and neuropeptide imbalance and their role in the pathophysiology of ASD and discussed some future research directions. PMID:25110424

Samsam, Mohtashem; Ahangari, Raheleh; Naser, Saleh A

2014-08-01

475

Pathophysiology of autism spectrum disorders: Revisiting gastrointestinal involvement and immune imbalance  

PubMed Central

Autism spectrum disorders (ASD) comprise a group of neurodevelopmental abnormalities that begin in early childhood and are characterized by impairment of social communication and behavioral problems including restricted interests and repetitive behaviors. Several genes have been implicated in the pathogenesis of ASD, most of them are involved in neuronal synaptogenesis. A number of environmental factors and associated conditions such as gastrointestinal (GI) abnormalities and immune imbalance have been linked to the pathophysiology of ASD. According to the March 2012 report released by United States Centers for Disease Control and Prevention, the prevalence of ASD has sharply increased during the recent years and one out of 88 children suffers now from ASD symptoms. Although there is a strong genetic base for the disease, several associated factors could have a direct link to the pathogenesis of ASD or act as modifiers of the genes thus aggravating the initial problem. Many children suffering from ASD have GI problems such as abdominal pain, chronic diarrhea, constipation, vomiting, gastroesophageal reflux, and intestinal infections. A number of studies focusing on the intestinal mucosa, its permeability, abnormal gut development, leaky gut, and other GI problem raised many questions but studies were somehow inconclusive and an expert panel of American Academy of Pediatrics has strongly recommended further investigation in these areas. GI tract has a direct connection with the immune system and an imbalanced immune response is usually seen in ASD children. Maternal infection or autoimmune diseases have been suspected. Activation of the immune system during early development may have deleterious effect on various organs including the nervous system. In this review we revisited briefly the GI and immune system abnormalities and neuropeptide imbalance and their role in the pathophysiology of ASD and discussed some future research directions. PMID:25110424

Samsam, Mohtashem; Ahangari, Raheleh; Naser, Saleh A

2014-01-01

476

Fractional flow in fractured chalk; a flow and tracer test revisited  

NASA Astrophysics Data System (ADS)

A multi-borehole pumping and tracer test in fractured chalk is revisited and reinterpreted in the light of fractional flow. Pumping test data analyzed using a fractional flow model gives sub-spherical flow dimensions of 2.2-2.4 which are interpreted as due to the partially penetrating nature of the pumped borehole. The fractional flow model offers greater versatility than classical methods for interpreting pumping tests in fractured aquifers but its use has been hampered because the hydraulic parameters derived are hard to interpret. A method is developed to convert apparent transmissivity and storativity (L4-n/T and S2-n) to conventional transmissivity and storativity (L2/T and dimensionless) for the case where flow dimension, 2 < n < 3. These parameters may then be used in further applications, facilitating application of the fractional flow model. In the case illustrated, improved fits to drawdown data are obtained and the resultant transmissivities and storativities are found to be lower by 30% and an order of magnitude respectively, than estimates from classical methods. The revised hydraulic parameters are used in a reinterpretation of a tracer test using an analytical dual porosity model of solute transport incorporating matrix diffusion and modified for fractional flow. Model results show smaller fracture apertures, spacings and dispersivities than those when 2D flow is assumed. The pumping and tracer test results and modeling presented illustrate the importance of recognizing the potential fractional nature of flow generated by partially penetrating boreholes in fractured aquifers in estimating aquifer properties and interpreting tracer breakthrough curves.

Odling, N. E.; West, L. J.; Hartmann, S.; Kilpatrick, A.

2013-04-01

477

The Light Curve of SN 1987A Revisited: Constraining Production Masses of Radioactive Nuclides  

NASA Astrophysics Data System (ADS)

We revisit the evidence for the contribution of the long-lived radioactive nuclides 44Ti, 55Fe, 56Co, 57Co, and 60Co to the UVOIR light curve of SN 1987A. We show that the V-band luminosity constitutes a roughly constant fraction of the bolometric luminosity between 900 and 1900 days, and we obtain an approximate bolometric light curve out to 4334 days by scaling the late time V-band data by a constant factor where no bolometric light curve data is available. Considering the five most relevant decay chains starting at 44Ti, 55Co, 56Ni, 57Ni, and 60Co, we perform a least squares fit to the constructed composite bolometric light curve. For the nickel isotopes, we obtain best fit values of M(56Ni) = (7.1 ± 0.3) × 10-2 M ? and M(57Ni) = (4.1 ± 1.8) × 10-3 M ?. Our best fit 44Ti mass is M(44Ti) = (0.55 ± 0.17) × 10-4 M ?, which is in disagreement with the much higher (3.1 ± 0.8) × 10-4 M ? recently derived from INTEGRAL observations. The associated uncertainties far exceed the best fit values for 55Co and 60Co and, as a result, we only give upper limits on the production masses of M(55Co) < 7.2 × 10-3 M ? and M(60Co) < 1.7 × 10-4 M ?. Furthermore, we find that the leptonic channels in the decay of 57Co (internal conversion and Auger electrons) are a significant contribution and constitute up to 15.5% of the total luminosity. Consideration of the kinetic energy of these electrons is essential in lowering our best fit nickel isotope production ratio to [57Ni/56Ni] = 2.5 ± 1.1, which is still somewhat high but is in agreement with gamma-ray observations and model predictions.

Seitenzahl, Ivo R.; Timmes, F. X.; Magkotsios, Georgios

2014-09-01

478

Theoretical investigation of the enzymatic phosphoryl transfer of ?-phosphoglucomutase: revisiting both steps of the catalytic cycle.  

PubMed

Enzyme catalyzed phosphate transfer is a part of almost all metabolic processes. Such reactions are of central importance for the energy balance in all organisms and play important roles in cellular control at all levels. Mutases transfer a phosphoryl group while nucleases cleave the phosphodiester linkages between two nucleotides. The subject of our present study is the Lactococcus lactis ?-phosphoglucomutase (?-PGM), which effectively catalyzes the interconversion of ?-D-glucose-1-phosphate (?-G1P) to ?-D-glucose-6-phosphate (?-G6P) and vice versa via stabile intermediate ?-D-glucose-1,6-(bis)phosphate (?-G1,6diP) in the presence of Mg(2+). In this paper we revisited the reaction mechanism of the phosphoryl transfer starting from the bisphosphate ?-G1,6diP in both directions (toward ?-G1P and ?-G6P) combining docking techniques and QM/MM theoretical method at the DFT/PBE0 level of theory. In addition we performed NEB (nudged elastic band) and free energy calculations to optimize the path and to identify the transition states and the energies involved in the catalytic cycle. Our calculations reveal that both steps proceed via dissociative pentacoordinated phosphorane, which is not a stabile intermediate but rather a transition state. In addition to the Mg(2+) ion, Ser114 and Lys145 also play important roles in stabilizing the large negative charge on the phosphate through strong coordination with the phosphate oxygens and guiding the phosphate group throughout the catalytic process. The calculated energy barrier of the reaction for the ?-G1P to ?-G1,6diP step is only slightly higher than for the ?-G1,6diP to ?-G6P step (16.10 kcal mol(-1) versus 15.10 kcal mol(-1)) and is in excellent agreement with experimental findings (14.65 kcal mol(-1)). PMID:22238068

Elsässer, Brigitta; Dohmeier-Fischer, Silvia; Fels, Gregor

2012-07-01

479

The Long Life of Birds: The Rat-Pigeon Comparison Revisited  

PubMed Central

The most studied comparison of aging and maximum lifespan potential (MLSP) among endotherms involves the 7-fold longevity difference between rats (MLSP 5y) and pigeons (MLSP 35y). A widely accepted theory explaining MLSP differences between species is the oxidative stress theory, which purports that reactive oxygen species (ROS) produced during mitochondrial respiration damage bio-molecules and eventually lead to the breakdown of regulatory systems and consequent death. Previous rat-pigeon studies compared only aspects of the oxidative stress theory and most concluded that the lower mitochondrial superoxide production of pigeons compared to rats was responsible for their much greater longevity. This conclusion is based mainly on data from one tissue (the heart) using one mitochondrial substrate (succinate). Studies on heart mitochondria using pyruvate as a mitochondrial substrate gave contradictory results. We believe the conclusion that birds produce less mitochondrial superoxide than mammals is unwarranted. We have revisited the rat-pigeon comparison in the most comprehensive manner to date. We have measured superoxide production (by heart, skeletal muscle and liver mitochondria), five different antioxidants in plasma, three tissues and mitochondria, membrane fatty acid composition (in seven tissues and three mitochondria), and biomarkers of oxidative damage. The only substantial and consistent difference that we have observed between rats and pigeons is their membrane fatty acid composition, with rats having membranes that are more susceptible to damage. This suggests that, although there was no difference in superoxide production, there is likely a much greater production of lipid-based ROS in the rat. We conclude that the differences in superoxide production reported previously were due to the arbitrary selection of heart muscle to source mitochondria and the provision of succinate. Had mitochondria been harvested from other tissues or other relevant mitochondrial metabolic substrates been used, then very different conclusions regarding differences in oxidative stress would have been reached. PMID:21904609

Montgomery, Magdalene K.; Hulbert, A. J.; Buttemer, William A.

2011-01-01

480

One-zone synchrotron self-Compton model for the core emission of Centaurus A revisited  

NASA Astrophysics Data System (ADS)

Aims: We investigate the role of the second synchrotron self-Compton (SSC) photon generation to the multiwavelength emission from the compact regions of sources that are characterized as misaligned blazars. For this, we focus on the nearest high-energy emitting radio galaxy Centaurus A and we revisit the one-zone SSC model for its core emission. Methods: We have calculated analytically the peak luminosities of the first and second SSC components by first deriving the steady-state electron distribution in the presence of synchrotron and SSC cooling, and then by using appropriate expressions for the positions of the spectral peaks. We have also tested our analytical results against those derived from a numerical code where the full emissivities and cross-sections were used. Results: We show that the one-zone SSC model cannot account for the core emission of Centaurus A above a few GeV, where the peak of the second SSC component appears. We thus propose an alternative explanation for the origin of the high-energy (?0.4 GeV) and TeV emission, where these are attributed to the radiation emitted by a relativistic proton component through photohadronic interactions with the photons produced by the primary leptonic component. We show that the required proton luminosities are not extremely high, i.e. ~1043 erg/s, provided that the injection spectra are modelled by a power law with a high value of the lower energy cutoff. Finally, we find that the contribution of the core emitting region of Cen A to the observed neutrino and ultra-high-energy cosmic-ray fluxes is negligible.

Petropoulou, M.; Lefa, E.; Dimitrakoudis, S.; Mastichiadis, A.

2014-02-01

481

Weak Lensing Measurements: A Revisited Method and Application toHubble Space Telescope Images  

NASA Astrophysics Data System (ADS)

The weak distortions produced by gravitational lensing in the images of background galaxies provide a unique method to measure directly the distribution of mass in the universe. However, because the induced distortions are only of a few percent, this technique requires high-precision measurements of the lensing shear and cautious corrections for systematic effects. Kaiser, Squires, & Broadhurst proposed a method to calibrate the ellipticity-shear relation in the presence of point-spread function (PSF) anisotropies and camera distortions. Here, we revisit the Kaiser, Squires, & Broadhurst method in the context of the demanding search for weak lensing by large-scale structure. We show that both the PSF and the camera distortions can be corrected for using source moments, as opposed to ellipticities. We clarify the applicability of some of the approximations made in this method. We derive expressions for the corrections that involve only the galaxy moments. By decomposing the moments into spinors, we derive an explicit relation between the shear and the average ellipticity. We discuss the shortcomings of the method and test its validity using numerical simulations. As an application of the method, we repeat the analysis of the Hubble Space Telescope (HST) WFPC2 camera performed by Hoekstra et al. We confirm the presence of sizable (~10%) PSF ellipticities at the edge of the WFPC2 chips. However, we find that the camera distortion is radial, rather than tangential. We also show that the PSF ellipticity varies by as much as 2% over time. We use these measurements to correct the shape of galaxies in the HST Survey Strip (the ``Groth'' Strip). By considering the dependence of the ellipticities on object size, we show that, after corrections, the residual systematic uncertainty for galaxies with radii greater than 0.15" is about 0.4% when averaged over each chip. We discuss how these results provide good prospects for measuring weak lensing by large-scale structure with deep HST surveys.

Rhodes, Jason; Refregier, Alexandre; Groth, Edward J.

2000-06-01

482

Non-24-Hour Disorder in Blind Individuals Revisited: Variability and the Influence of Environmental Time Cues  

PubMed Central

Study Objectives: To assess the interindividual and intraindividual variability in the circadian rhythms of blind individuals with non-24-h disorder and to quantify the influence of environmental time cues in blind subjects lacking entrainment (non-24-h individuals or N-24s). Design: An observational study of 21 N-24s (11 females and 10 males, age 9-78 years) who kept a sleep/wake schedule of their choosing. Circadian phase was determined using the melatonin onset (MO) from plasma or saliva samples that were collected every 2 weeks. Melatonin concentrations were measured by radioimmunoassay. A total of 469 MO assessments were conducted over 5,536 days of study. The rate of drift of circadian phase was calculated using a series of MOs (total number of hours the MO drifted divided by the total number of days studied). Stability of the rest/activity rhythm was calculated using chi-squared periodogram analysis of wrist actigraphy data in 19 subjects. Setting: Academic medical center. Participants: Paid volunteers. Interventions: N/A. Measurements and Results: Subjects lacked entrainment such that circadian phase drifted an average (± standard deviation) of 0.39 ± 0.29 h later per day; however, there was notable intersubject and intrasubject variability in the rate of drift including relative coordination and periods of transient entrainment during which there was little to no drift in the circadian phase. A regular, reproducible, and significant oscillation in the rate of drift was detected in 14 of the 21 subjects. A significant non-24-h rest/activity rhythm was detected in 18 of 19 subjects. There was a strong correlation (r = 0.793, P = 0.0001) between the non-24-h rest/activity rhythm and the rate of drift of the circadian phase. Conclusions: Most N-24s are influenced by unidentified environmental time cues and the non-entrained biological clock in such N-24s is reflected in their rest/activity rhythms. These findings may have diagnostic and treatment implications: this disorder might be diagnosed with actigraphy alone, relative coordination and transient entrainment may result in misdiagnosis and responsiveness to environmental time cues may influence treatment success with oral melatonin. Citation: Emens JS; Laurie AL; Songer JB; Lewy AJ. Non-24-hour disorder in blind individuals revisited: variability and the influence of environmental time cues. SLEEP 2013;36(7):1091-1100. PMID:23814347

Emens, Jonathan S.; Laurie, Amber L.; Songer, Jeannie B.; Lewy, Alfred J.

2013-01-01

483

Revisiting the influence of particle size on the equilibrium composition of organic aerosol  

NASA Astrophysics Data System (ADS)

Atmospheric aerosol particles are comprised of both inorganic and organic compounds. Whilst the inorganic fraction is relatively well characterised, the organic fraction can comprise many thousands of largely unidentified compounds with a wide range of properties. This presents challenges when attempting to reconcile particulate composition and behaviour in the atmosphere. In addition, the size of an aerosol particle influences the equilibrium composition and phase state for a given set of ambient conditions and availability of semi-volatile material. Incorporating the influence of curvature in theoretical constructs can be complex. Unfortunately, basic absorptive equilibrium partitioning models largely neglect the influence of curvature, leading to errors in predicted composition and volatility for conditions in which size is likely to play an important role: new particle formation or cloud activation. In this study we present application of a partitioning model that explicitly accounts for impact of curvature on the equilibrium position for particles of any size and comprised of an unlimited number of compounds. Using this framework we are able to revisit predictions of cloud activation potential for organic aerosol with multiple semi-volatile fractions. Whilst the influence of curvature is explicit within the Kohler equation, this only accounts for the equilibration of water between and gaseous and particle phase. Direct use of the Kohler equation therefore does not implicitly account for the co-condensation/evaporation of semi-volatile components as the relative humidity changes. We show that equilibration of explicit consideration of gas to particle partitioning for atmospherically reasonable concentrations of any number of organic compounds with a growing particle as the ambient humidity increases has potentially larger implications on cloud activation than any other equilibrium compositional dependence, Replicating the true atmospheric behaviour of aerosol particles poses challenges for both the modelling and measurement community, our simulations suggesting it is impossible to uncouple composition and size in studying the role of aerosol particles in radiative forcing, as once previously thought. In addition to predictions of cloud activation potential allowing co-codensation of any number of organic compounds, we are able to explore generalised relationships between aerosol functionality and particle size. This allows us to probe the relationships between required abundance and volatility for those compounds expected to take part in the growth of freshly nucleated particles. A discussion of the caveats behind this approach is given, along with pitfalls of not explictly accounting for aerosol size in previously applied predictive frameworks with potential impacts of subsequent aerosol properties.

Topping, D. O.; McFiggans, G.

2011-12-01

484

The [C II] 158 Micron Line in Ultraluminous Infrared Galaxies Revisited  

NASA Technical Reports Server (NTRS)

We present a study of the [C II] 157.74 micron fine-structure line in a sample of 15 ultraluminous infrared (IR) galaxies (IR luminosity L(sub IR greater than or equal to 10(exp 12)L.; ULIRGs) using the Long Wavelength Spectrometer (LWS) on the Infrared Space Observatory (ISO). We confirm the observed order of magnitude deficit (compared to normal and starburst galaxies) in the strength of the [C II] line relative to the far-infrared (FIR) dust continuum emission found in our initial report, but here with a sample that is twice as large. This result suggests that the deficit is a general phenomenon affecting 4 out of 5 ULIRGs. We present an analysis using observations of generally acknowledged photodissociation region (PDR) tracers ([C II], [OI] 63 and 145 micron, and FIR continuum emission), which suggests that a high ultraviolet flux G(sub 0) incident on a moderate density n PDR could explain the deficit. However, comparisons with other ULIRG observations, including CO (1-0), [C I] (1-0), and 6.2 micron polycyclic aromatic hydrocarbon (PAH) emission, suggest that high G(sub 0)/n PDRs alone cannot produce a self-consistent solution that is compatible with all of the observations. We propose that non-PDR contributions to the FIR continuum can explain the apparent [C II] deficiency. Here, unusually high G(sub 0) and/ or n physical conditions in ULIRGs as compared to those in normal and starburst galaxies are not required to explain the [C II] deficit. Dust-bounded photoionization regions, which generate much of the FIR emission but do not contribute significant [C II] emission, offer one possible physical origin for this additional non-PDR component. Such environments may also contribute to the observed suppression of FIR fine-structure emission from ionized gas and PAHs, as well as the warmer FIR colors found in ULIRGs. The implications for observations at higher redshifts are also revisited.

Luhman, M. L.; Satyapal, S.; Fischer, J.; Wolfire, M. G.; Sturm, E.; Dudley, C. C.; Lutz, D.; Genzel, R.

2003-01-01

485

Kursk Magnetic Anomaly at Satellite Altitude: Revisited with the Orsted Satellite  

NASA Technical Reports Server (NTRS)

The Kursk Magnetic Anomaly (KMA) of Russia (51 deg north, 37 deg east) has long been recognized as one of the largest magnetic anomalies on Earth. It is associated with the massive iron-ore formations of this region, however, model studies have revealed that the relationship between the two is not obvious. In an early effort to demonstrate the validity of Magsat data for crustal research a detailed study of the KMA, at an average altitude of 350 km and the surrounding region was made. They recorded a 27 nT high and a -9 nT low giving a 37 nT peak-to-trough anomaly over the immediate area of the KMA. Despite the much higher altitude of Orsted (620 to 850 km) we revisited the KMA to determine if this mission would also be able to record an associated anomalous crustal signature. The Orsted profiles we selected were from April to August 1999. From these data we chose those with an altitude range of 644 to 700 km and they were subsequently gridded, by least-squares collocation, to a mean elevation of 660 km. Both ascending and descending data were examined and signals common to both were extracted and averaged. A correlation coefficient between these two orbit orientations of 0.82 was computed. The quadrant-swapping method of Kim et al. was applied. Removal of the main geomagnetic field was accomplished with a polynomial fitting procedure. A positive anomaly of >2.5 nT with ari associated negative of <-0.5 nT for a >3 nT peak-to-trough range were computed. These Magsat and Orsted results are consistent with the decay of a dipole field over the studied altitude range. Significant differences between these two anomaly fields are due to the greater number of orbit profiles and therefore greater number of intersecting orbits (ascending and descending) available in the Orsted compilation. Of the four largest amplitude anomalies in the Orsted field three are present in the Magsat map. The fourth (>2.5 nT), however, is associated with the Belorussian-Lithuanian anteclise. This sugaests that additional geologic information may be apparent in the new Orsted field.

Taylor, Patrick T.; VonFrese, Ralph R. B.; Kim, Hyung Rae

2000-01-01

486

H I kinematics of the Large Magellanic Cloud revisited: Evidence of possible infall and outflow  

NASA Astrophysics Data System (ADS)

Aims: The neutral atomic Hydrogen (H i) kinematics of the Large Magellanic Cloud (LMC) is revisited in light of two new proper motion estimates. Methods: We analysed the intensity weighted H I velocity maps of the Australia Telescope Compact Array (ATCA)/Parkes and the Parkes Galactic all sky survey (GASS) data sets. We corrected the line-of-sight velocity field for the systemic, transverse, precession, and nutation motions of the disk using two recent proper motion estimates, and estimated the kinematic parameters of the H I disk. Results: The value of position angle (PA) of kinematic major axis estimated using ATCA/Parkes data (126° ± 23°) is found to be similar to the recent estimate of the PA using stellar tracers. The effect of precession and nutation in the estimation of PA is found to be significant. The modelled H I disk is found to be disturbed within 1.?0 radius and beyond 2.?9 radius. Using ATCA/Parkes data, most of the H I gas in the LMC (~87.9% of the data points) is found to be located in the disk. We detected 12.1% of the data points as kinematic outliers. A significant part of type 1 as well as slow type 2 H I gas is identified with Arm E. We identified the well-known Arm S, Arm W, Arm B and a new stream, Outer Arm, as part of fast type 2 outlier component. The GASS data analysis brings out the velocity details of the Magellanic Bridge (MB) and its connection to the LMC disk. We find that the Arm B and the Outer Arm are connected to the MB. We detect high velocity gas in the western disk of the LMC and the south-west and southern parts of the MB. Conclusions: We proposed two models (in-plane and out-of-plane) to explain the outlier gas. We suggest that the Arm B could be an infall feature, originating from the inner MB. The Arm E could be an outflow feature. We suggest possible outflows from the western LMC disk and south and south-western MB, which could be due to ram pressure. The velocity pattern observed in the MB suggests that it is being sheared. We suggest that the various outliers identified in this study may be caused by a combination of tidal effects and hydrodynamical effect due to the motion of the LMC in the Milky Way halo.

Indu, Gopalakrishnan; Subramaniam, Annapurni

2015-01-01

487

Modelling crystal plasticity by 3D dislocation dynamics and the finite element method: The Discrete-Continuous Model revisited  

NASA Astrophysics Data System (ADS)

A unified model coupling 3D dislocation dynamics (DD) simulations with the finite element (FE) method is revisited. The so-called Discrete-Continuous Model (DCM) aims to predict plastic flow at the (sub-)micron length scale of materials with complex boundary conditions. The evolution of the dislocation microstructure and the short-range dislocation-dislocation interactions are calculated with a DD code. The long-range mechanical fields due to the dislocations are calculated by a FE code, taking into account the boundary conditions. The coupling procedure is based on eigenstrain theory, and the precise manner in which the plastic slip, i.e. the dislocation glide as calculated by the DD code, is transferred to the integration points of the FE mesh is described in full detail. Several test cases are presented, and the DCM is applied to plastic flow in a single-crystal Nickel-based superalloy.

Vattré, A.; Devincre, B.; Feyel, F.; Gatti, R.; Groh, S.; Jamond, O.; Roos, A.

2014-02-01

488

Revisiting Coincidence Rate between Gravitational Wave Detection and Short Gamma-Ray Burst for the Advanced and Third Generation  

NASA Astrophysics Data System (ADS)

We use realistic Monte Carlo simulations including both gravitational-wave (GW) and short gamma-ray burst (sGRB) selection effects to revisit the coincident rate of binary systems composed of two neutron stars or a neutron star and a black hole. We show that the fraction of GW triggers that can be observed in coincidence with sGRBs is proportional to the beaming factor at z = 0, but increases with the distance until it reaches 100% at the GW detector horizon distance. When this is taken into account the rate is improved by a factor of three compared to the simple beaming factor correction. We provide an estimate of the performance future GRB detectors should achieve in order to fully exploit the potentiality of the planned third-generation GW antenna Einstein Telescope, and we propose a simple method to constrain the beaming angle of sGRBs.

Regimbau, T.; Siellez, K.; Meacher, D.; Gendre, B.; Boër, M.

2015-01-01

489

Article publi dans Articulo Journal Urban Research, 2010, Hors-srie n3 "Revisiting Urbanity and Rurality" : http://articulo.revues.org/1524  

E-print Network

Article publié dans Articulo ­ Journal Urban Research, 2010, Hors-série n°3 "Revisiting Urbanity and Rurality" : http://articulo.revues.org/1524 Les espaces périurbains non bâtis en France : entre publicisation « urbaine » et privatisation « rurale » ? Banos Vincent1 et Sabatier Bruno2 Version auteurs Résumé

Paris-Sud XI, Université de

490

Revisiting Melton: Analyzing the correlation structure of geomorphological and climatological parameters  

NASA Astrophysics Data System (ADS)

In his expansive 1957 study of over 80 basins in Arizona, Colorado, New Mexico, and Utah, Mark Melton measured key morphometric, soil, land cover, and climatic parameters [Melton, 1957]. He identified correlations between morphological parameters and climatic regimes in an attempt to characterize the geomorphology of the basin as a function of climate and vegetation. Using modern techniques such as high resolution digital terrain models in combination with high spatial resolution weather station records, vector soil maps, seamless raster geological data, and land cover vector maps, we revisit Melton's 1957 dataset with the following hypotheses: (1) Patterns of channelization carry strong, codependent signatures in the form of statistical correlations of rainfall variability, soil type, and vegetation patterns. (2) Channelization patterns reflect the erosion processes on sub-catchment scale and the subsequent processes of vegetation recovery and gullying. In order to characterize various topographic and climatic parameters, we obtain elevation and land cover data from the USGS National Elevation dataset, climate data from the Western Regional Climate Center and PRISM climate group database, and soil type from the USDA STATSGO soil database. We generate a correlative high resolution database on vegetation, soil cover, lithology, and climatology for the basins identified by Melton in his 1957 study. Using the GeoNet framework developed by Passalacqua et al. [2010], we extract various morphological parameters such as slope, drainage density, and stream frequency. We also calculate metrics for patterns of channelization such as number of channelized pixels in a basin and channel head density. In order to understand the correlation structure between climate and morphological variables, we compute the Pearson's correlation coefficient similar to Melton's analysis and also explore other statistical procedures to characterize the feedbacks between these variables. By identifying the differences in Melton's and our results, we address the influence of climate over the degree of channel dissection in the landscape. References: Melton, M. A. (1957). An analysis of the relations among elements of climate, surface properties, and geomorphology (No. CU-TR-11). COLUMBIA UNIV NEW YORK Passalacqua, P., Do Trung, T., Foufoula-Georgiou, E., Sapiro, G., & Dietrich, W. E. (2010). A geometric framework for channel network extraction from lidar: Nonlinear diffusion and geodesic paths. Journal of Geophysical Research: Earth Surface (2003-2012), 115(F1). PRISM Climate Group, Oregon State University, http://prism.oregonstate.edu, created 4 Feb 2004 Soil Survey Staff, Natural Resources Conservation Service, United States Department of Agriculture. U.S. General Soil Map (STATSGO2). Available online at http://soildatamart.nrcs.usda.gov USGS National Map Viewer, United States Geological Survey. Web. 10 June 2013. http://viewer.nationalmap.gov/viewer/ Western U.S. Historical Climate Summaries, Western Regional Climate Group, 2013. Web. 10 June 2013. http://www.wrcc.dri.edu/Climsum.html

Carothers, R. A.; Sangireddy, H.; Passalacqua, P.

2013-12-01