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1

Decreased white matter integrity in fronto-occipital fasciculus bundles: relation to visual information processing in alcohol-dependent subjects.  

PubMed

Chronic alcohol abuse is characterized by impaired cognitive abilities with a more severe deficit in visual than in verbal functions. Neuropathologically, it is associated with widespread brain structural compromise marked by gray matter shrinkage, ventricular enlargement, and white matter degradation. The present study sought to increase current understanding of the impairment of visual processing abilities in alcohol-dependent subjects, and its correlation with white matter microstructural alterations, using diffusion tensor imaging (DTI). To that end, a DTI study was carried out on 35 alcohol-dependent subjects and 30 healthy male control subjects. Neuropsychological tests were assessed for visual processing skills and deficits were reported as raw dysfunction scores (rDyS). Reduced FA (fractional anisotropy) and increased MD (mean diffusivity) were observed bilaterally in inferior and superior fronto-occipital fasciculus (FOF) fiber bundles. A significant inverse correlation in rDyS and FA values was observed in these fiber tracts whereas a positive correlation of these scores was found with the MD values. Our results suggest that FOF fiber bundles linking the frontal lobe to occipital lobe might be related to visual processing skills. This is the first report of an alteration of the white matter microstructure of FOF fiber bundles that might have functional consequences for visual processing in alcohol-dependent subjects who exhibit no neurological complications. PMID:24388377

Bagga, Deepika; Sharma, Aakansha; Kumari, Archana; Kaur, Prabhjot; Bhattacharya, Debajyoti; Garg, Mohan Lal; Khushu, Subash; Singh, Namita

2014-02-01

2

The anatomy of fronto-occipital connections from early blunt dissections to contemporary tractography.  

PubMed

The occipital and frontal lobes are anatomically distant yet functionally highly integrated to generate some of the most complex behaviour. A series of long associative fibres, such as the fronto-occipital networks, mediate this integration via rapid feed-forward propagation of visual input to anterior frontal regions and direct top-down modulation of early visual processing. Despite the vast number of anatomical investigations a general consensus on the anatomy of fronto-occipital connections is not forthcoming. For example, in the monkey the existence of a human equivalent of the 'inferior fronto-occipital fasciculus' (iFOF) has not been demonstrated. Conversely, a 'superior fronto-occipital fasciculus' (sFOF), also referred to as 'subcallosal bundle' by some authors, is reported in monkey axonal tracing studies but not in human dissections. In this study our aim is twofold. First, we use diffusion tractography to delineate the in vivo anatomy of the sFOF and the iFOF in 30 healthy subjects and three acallosal brains. Second, we provide a comprehensive review of the post-mortem and neuroimaging studies of the fronto-occipital connections published over the last two centuries, together with the first integral translation of Onufrowicz's original description of a human fronto-occipital fasciculus (1887) and Muratoff's report of the 'subcallosal bundle' in animals (1893). Our tractography dissections suggest that in the human brain (i) the iFOF is a bilateral association pathway connecting ventro-medial occipital cortex to orbital and polar frontal cortex, (ii) the sFOF overlaps with branches of the superior longitudinal fasciculus (SLF) and probably represents an 'occipital extension' of the SLF, (iii) the subcallosal bundle of Muratoff is probably a complex tract encompassing ascending thalamo-frontal and descending fronto-caudate connections and is therefore a projection rather than an associative tract. In conclusion, our experimental findings and review of the literature suggest that a ventral pathway in humans, namely the iFOF, mediates a direct communication between occipital and frontal lobes. Whether the iFOF represents a unique human pathway awaits further ad hoc investigations in animals. PMID:23137651

Forkel, Stephanie J; Thiebaut de Schotten, Michel; Kawadler, Jamie M; Dell'Acqua, Flavio; Danek, Adrian; Catani, Marco

2014-07-01

3

Maxillary changes and occlusal traits in crania with artificial fronto-occipital deformation.  

PubMed

Artificial fronto-occipital deformation of the cranial vault was typical of pre-Columbian cultures in the central Andean coastal regions. We have studied the influence of this deformation on maxillary and mandibular morphology. Measurements were performed on 86 adult Ancon skulls with anteroposterior deformation. Undeformed skulls from the area of Makatampu (n = 52) were used as the control group. To explore the influence of the deformity on occlusion, the skulls were categorized using the Angle classification and the alignment of the interincisor midline. In the group of deformed skulls, there was an increase in lateral growth of the vault and of the base of the skull (P < 0.001), giving rise to a greater interpterygoid width of the maxilla (P < 0.001), and an increase in the transverse diameter of the palatal vault. The mandible presented an increase in the length of the rami (P < 0.001) and in the intercondylar width, with no alteration of mandibular length. The deformed skulls had normal (class I) occlusion, with no displacement of the midline. The difference in the asymmetry index between the two groups was not statistically significant. Artificial fronto-occipital deformation of the cranial vault provoked compensatory lateral expansion of the base that was correlated with the transverse development of the maxilla and mandible. Occlusion and sagittal intermaxillary position were not affected by the cranial deformity. These results provide evidence of the integration between the neurocranium and the viscerocranium in craniofacial development, and support the hypothesis of a compensatory effect of function. PMID:21990029

Jimenez, Publio; Martinez-Insua, Arturo; Franco-Vazquez, Jaime; Otero-Cepeda, Xose Luis; Santana, Urbano

2012-01-01

4

Beyond the arcuate fasciculus: consensus and controversy in the connectional anatomy of language.  

PubMed

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 function, but recent investigations using a variety of methodologies in both humans and non-human primates have provided conflicting accounts of pathways central to language. Some of the pathways classically considered language pathways, such as the arcuate fasciculus, are now argued to be domain-general rather than specialized, which represents a radical shift in perspective. Other pathways described in the non-human primate remain to be verified in humans. In this review, we examine the consensus and controversy in the study of fibre pathway connectivity for language. We focus on seven fibre pathways-the superior longitudinal fasciculus and arcuate fasciculus, the uncinate fasciculus, extreme capsule, middle longitudinal fasciculus, inferior longitudinal fasciculus and inferior fronto-occipital fasciculus-that have been proposed to support language in the human. We examine the methods in humans and non-human primate used to investigate the connectivity of these pathways, the historical context leading to the most current understanding of their anatomy, and the functional and clinical correlates of each pathway with reference to language. We conclude with a challenge for researchers and clinicians to establish a coherent framework within which fibre pathway connectivity can be systematically incorporated to the study of language. PMID:23107648

Dick, Anthony Steven; Tremblay, Pascale

2012-12-01

5

BRAINA JOURNAL OF NEUROLOGY White matter structural connectivity underlying  

E-print Network

and fractional anisotropy value of the left inferior fronto-occipital fasciculus, left anterior thalamic. These results underscore the causal role of left inferior fronto-occipital fasciculus, left anterior thalamic-damaged patient Abbreviations: ATR = anterior thalamic radiation; IFOF = inferior fronto-occipital fasciculus

Caramazza, Alfonso

6

Uncinate fasciculus abnormalities in recent onset schizophrenia and affective psychosis: A diffusion tensor imaging study  

E-print Network

years of first hospitalization (12 patients with schizophrenia and 12 patients with affective psychosisUncinate fasciculus abnormalities in recent onset schizophrenia and affective psychosis studies in chronic schizophrenia are the uncinate fasciculus (UF) and cingulum bundle (CB). The purpose

7

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

8

DIFFUSION TENSOR IMAGING OF THE UNCINATE FASCICULUS IN FIRST-EPISODE SCHIZOPHRENIA  

E-print Network

DIFFUSION TENSOR IMAGING OF THE UNCINATE FASCICULUS IN FIRST-EPISODE SCHIZOPHRENIA DIFFUSION TENSOR IMAGING OF THE UNCINATE FASCICULUS IN FIRST-EPISODE SCHIZOPHRENIA BACKGROUND This study compares diffusion) to those of age-matched controls (NCs). METHODS Diffusion-weighted images (DWI) were acquired on a 3T GE

9

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

10

Reading impairment in a patient with missing arcuate fasciculus  

PubMed Central

We describe the case of a child (“S”) who was treated with radiation therapy at age 5 for a recurrent malignant brain tumor. Radiation successfully abolished the tumor but caused radiation-induced tissue necrosis, primarily affecting cerebral white matter. S was introduced to us at age 15 because of her profound dyslexia. We assessed cognitive abilities and performed diffusion tensor imaging (DTI) to measure cerebral white matter pathways. Diffuse white matter differences were evident in T1-weighted, T2-weighted, diffusion anisotropy, and mean diffusivity measures in S compared to a group of 28 normal female controls. In addition, we found specific white matter pathway deficits by comparing tensor orientation directions in S’s brain with those of the control brains. While her principal diffusion direction maps appeared consistent with those of controls over most of the brain, there were tensor orientation abnormalities in the fiber tracts that form the superior longitudinal fasciculus (SLF) in both hemispheres. Tractography analysis indicated that the left and right arcuate fasciculus (AF), as well as other tracts within the SLF, were missing in S. Other major white matter tracts, such as the corticospinal and inferior occipitofrontal pathways, were intact. Functional MRI measurements indicated left-hemisphere dominanance for language with a normal activation pattern. Despite the left AF abnormality, S had preserved oral language with average sentence repetition skills. In addition to profound dyslexia, S exhibited visuospatial, calculation, and rapid naming deficits and was impaired in both auditory and spatial working memory. We propose that the reading and visuospatial deficits were due to the abnormal left and right SLF pathways, respectively. These results advance our understanding of the functional significance of the SLF and are the first to link radiation necrosis with selective damage to a specific set of fiber tracts. PMID:18775735

Rauschecker, Andreas M.; Deutsch, Gayle K.; Ben-Shachar, Michal; Schwartzman, Armin; Perry, Lee M.; Dougherty, Robert F.

2009-01-01

11

Uncinate Fasciculus Abnormalities in Recent Onset Schizophrenia and Affective Psychosis: A Diffusion Tensor  

E-print Network

Uncinate Fasciculus Abnormalities in Recent Onset Schizophrenia and Affective Psychosis Neuroscience Division, Laboratory of Neuroscience, Department of Psychiatry, Boston Veterans Affairs Healthcare Cognitive Neuroscience Laboratory, McLean Hospital, Department of Psychiatry, Harvard Medical School

12

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

13

Learning to read improves the structure of the arcuate fasciculus.  

PubMed

The acquisition of literacy results from an effortful learning process that leads to functional changes in several cortical regions. We explored whether learning to read also leads to anatomical changes within the left intrahemispheric white matter pathways that interconnect these regions. Using diffusion tensor imaging tractography, we compared illiterates with ex-illiterates who learned to read during adulthood and literates who learned to read during their childhood. Literacy related to an increase in fractional anisotropy and a decrease in perpendicular diffusivity in the temporo-parietal portion of the left arcuate fasciculus. The microstructure within this pathway correlated with the reading performance and the degree of functional activation within 2 dominant brain regions involved in reading: The Visual Word Form Area in response to letter strings, and the posterior superior temporal cortex in response to spoken language. Thus, the acquisition of literacy is associated with a reinforcement of left temporo-parietal connections whose microstructure predicts overall reading performance and the functional specialization of the Visual Word Form Area. This anatomical magnetic resonance imaging marker may be useful to predict developmental reading disorders. PMID:23236205

Thiebaut de Schotten, Michel; Cohen, Laurent; Amemiya, Eduardo; Braga, Lucia W; Dehaene, Stanislas

2014-04-01

14

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

E-print Network

schizophrenia patients and 18 male control subjects, group-matched for age, parental socio- economic statusCingulate Fasciculus Integrity Disruption in Schizophrenia: A Magnetic Resonance Diffusion Tensor gyrus (CG), may play a role in the pathophysi- ology of schizophrenia; however, the cingulum bundle (CB

15

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

Microsoft Academic Search

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 variation in the microstructural properties of arcuate fibers and behavioral

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

2011-01-01

16

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

17

The relationship between uncinate fasciculus white matter integrity and verbal memory proficiency in children.  

PubMed

During childhood, verbal learning and memory are important for academic performance. Recent functional MRI studies have reported on the functional correlates of verbal memory proficiency, but few have reported the underlying structural correlates. The present study sought to test the relationship between fronto-temporal white matter integrity and verbal memory proficiency in children. Diffusion weighted images were collected from 17 Black children (age 8-11 years) who also completed the California Verbal Learning Test. To index white matter integrity, fractional anisotropy values were calculated for bilateral uncinate fasciculus. The results revealed that low anisotropy values corresponded to poor verbal memory, whereas high anisotropy values corresponded to significantly better verbal memory scores. These findings suggest that a greater degree of myelination and cohesiveness of axonal fibers in uncinate fasciculus underlie better verbal memory proficiency in children. PMID:24949818

Schaeffer, David J; Krafft, Cynthia E; Schwarz, Nicolette F; Chi, Lingxi; Rodrigue, Amanda L; Pierce, Jordan E; Allison, Jerry D; Yanasak, Nathan E; Liu, Tianming; Davis, Catherine L; McDowell, Jennifer E

2014-08-20

18

Letter to the Editors The uncinate fasciculus and extraversion in schizotypal  

E-print Network

Letter to the Editors The uncinate fasciculus and extraversion in schizotypal personality disorder extraversion and agreeableness (Gurrera et al., 2005a). Since brain regions connected by the UF play important), and lower mean Extraversion (43.6±13.5 vs. 59.7±4.9, t=-3.20, df=17, p=.005) and Agreeableness (41.8±14.1 vs

19

Microstructural connectivity of the arcuate fasciculus in adolescents with high-functioning autism  

PubMed Central

The arcuate fasciculus is a white matter fiber bundle of great importance in language. In this study, diffusion tensor imaging (DTI) was used to infer white matter integrity in the arcuate fasciculi of a group of subjects with high-functioning autism and a control group matched for age, handedness, IQ, and head size. The arcuate fasciculus for each subject was automatically extracted from the imaging data using a new volumetric DTI segmentation algorithm. The results showed a significant increase in mean diffusivity (MD) in the autism group, due mostly to an increase in the radial diffusivity (RD). A test of the lateralization of DTI measurements showed that both MD and fractional anisotropy (FA) were less lateralized in the autism group. These results suggest that white matter microstructure in the arcuate fasciculus is affected in autism and that the language specialization apparent in the left arcuate of healthy subjects is not as evident in autism, which may be related to poorer language functioning. PMID:20132894

Fletcher, P. Thomas; Whitaker, Ross T.; Tao, Ran; DuBray, Molly B.; Froehlich, Alyson; Ravichandran, Caitlin; Alexander, Andrew L.; Bigler, Erin D.; Lange, Nicholas; Lainhart, Janet E.

2010-01-01

20

Quantification of the spatiotemporal microstructural organization of the human brain association, projection and commissural pathways across the lifespan using diffusion tensor tractography  

PubMed Central

Using diffusion tensor tractography, we quantified the microstructural changes in the association, projection, and commissural compact white matter pathways of the human brain over the lifespan in a cohort of healthy right-handed children and adults aged 6–68 years. In both males and females, the diffusion tensor radial diffusivity of the bilateral arcuate fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, corticospinal, somatosensory tracts, and the corpus callosum followed a U-curve with advancing age; fractional anisotropy in the same pathways followed an inverted U-curve. Our study provides useful baseline data for the interpretation of data collected from patients. PMID:20127357

Kamali, Arash; Abid, Humaira; Kramer, Larry A.; Fletcher, Jack M.; Ewing-Cobbs, Linda

2010-01-01

21

'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

22

A Combined fMRI and DTI Examination of Functional Language Lateralization and Arcuate Fasciculus Structure: Effects of Degree versus Direction of Hand Preference  

ERIC Educational Resources Information Center

The present study examined the relationship between hand preference degree and direction, functional language lateralization in Broca's and Wernicke's areas, and structural measures of the arcuate fasciculus. Results revealed an effect of degree of hand preference on arcuate fasciculus structure, such that consistently-handed individuals,…

Propper, Ruthe E.; O'Donnell, Lauren J.; Whalen, Stephen; Tie, Yanmei; Norton, Isaiah H.; Suarez, Ralph O.; Zollei, Lilla; Radmanesh, Alireza; Golby, Alexandra J.

2010-01-01

23

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

PubMed Central

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

Liegeois, Frederique J.; Mahony, Kate; Connelly, Alan; Pigdon, Lauren; Tournier, Jacques-Donald; Morgan, Angela T.

2013-01-01

24

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

25

Diffusion tensor tractography of the arcuate fasciculus in patients with brain tumors: Comparison between deterministic and probabilistic models  

PubMed Central

Purpose The purpose of this study was to compare the deterministic and probabilistic tracking methods of diffusion tensor white matter fiber tractography in patients with brain tumors. Materials and Methods We identified 29 patients with left brain tumors <2 cm from the arcuate fasciculus who underwent pre-operative language fMRI and DTI. The arcuate fasciculus was reconstructed using a deterministic Fiber Assignment by Continuous Tracking (FACT) algorithm and a probabilistic method based on an extended Monte Carlo Random Walk algorithm. Tracking was controlled using two ROIs corresponding to Broca’s and Wernicke’s areas. Tracts in tumoraffected hemispheres were examined for extension between Broca’s and Wernicke’s areas, anterior-posterior length and volume, and compared with the normal contralateral tracts. Results Probabilistic tracts displayed more complete anterior extension to Broca’s area than did FACT tracts on the tumor-affected and normal sides (p < 0.0001). The median length ratio for tumor: normal sides was greater for probabilistic tracts than FACT tracts (p < 0.0001). The median tract volume ratio for tumor: normal sides was also greater for probabilistic tracts than FACT tracts (p = 0.01). Conclusion Probabilistic tractography reconstructs the arcuate fasciculus more completely and performs better through areas of tumor and/or edema. The FACT algorithm tends to underestimate the anterior-most fibers of the arcuate fasciculus, which are crossed by primary motor fibers.

Li, Zhixi; Peck, Kyung K.; Brennan, Nicole P.; Jenabi, Mehrnaz; Hsu, Meier; Zhang, Zhigang; Holodny, Andrei I.; Young, Robert J.

2014-01-01

26

Diffusion Tensor Imaging Studies on Arcuate Fasciculus in Stroke Patients: A Review  

PubMed Central

Aphasia is one of the most common and devastating sequelae of stroke. The arcuate fasciculus (AF), an important neural tract for language function, connects Broca’s and Wernicke’s areas. In this review article, previous diffusion tensor imaging (DTI) studies on the AF in stroke patients were reviewed with regard to the usefulness for diagnosis (seven studies), prediction of prognosis (two studies), and recovery of aphasia (three studies). Although scant studies on this topic have been conducted in stroke patients, DTI for the AF appears to provide useful information on the presence or severity of injury of the AF, prognosis prediction of aphasia, and recovery mechanisms of aphasia in stroke patients. Therefore, further DTI studies on these topics should be encouraged, especially studies on prognosis prediction and recovery mechanisms of aphasia. In addition, research on other neural tracts known to be involved in aphasia as well as the AF in both hemispheres should be encouraged. PMID:24198780

Jang, Sung Ho

2013-01-01

27

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

28

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

29

Revisiting Lasswell  

Microsoft Academic Search

This article continues the line of argument and historical interpretation we offered in “The Policy Scientist of Democracy:\\u000a The Discipline of Harold D. Lasswell” by way of a response to Ronald Brunner’s “The Policy Scientist of Democracy Revisited.”\\u000a Problems regarding Lasswell’s capacious vision of the policy scientist and vagaries surrounding “democracy,” do not diminish\\u000a the importance of the questions Lasswell

James Farr; Jacob S. Hacker; Nicole Kazee

2008-01-01

30

White matter alterations in temporal lobe epilepsy  

NASA Astrophysics Data System (ADS)

In This study, we used Fractional anisotropy (FA), mean diffusivity (D), parallel diffusivity (D//) and perpendicular diffusivity (D), to localize the regions where occur axonal lesion and demyelization. TBSS was applied to analyze the FA data. After, the regions with alteration were studied with D, D// and D maps. Patients exhibited widespread degradation of FA. With D, D// and D maps analysis we found alterations in corpus callosum, corticospinal tract, fornix, internal capsule, corona radiate, Sagittal stratum, cingulum, fronto-occipital fasciculus and uncinate fasciculus. Our results are consistent with the hypothesis that exist demyelization and axonal damage in patients with TLE.

Diniz, P. B.; Salmon, C. E.; Velasco, T. R.; Sakamoto, A. C.; Leite, J. P.; Santos, A. C.

2011-03-01

31

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

32

42 CFR 488.30 - Revisit user fee for revisit surveys.  

Code of Federal Regulations, 2010 CFR

... false Revisit user fee for revisit surveys. 488.30 Section 488.30 Public...CONTINUED) STANDARDS AND CERTIFICATION SURVEY, CERTIFICATION, AND ENFORCEMENT PROCEDURES...488.30 Revisit user fee for revisit surveys. (a) Definitions. As used...

2010-10-01

33

42 CFR 488.30 - Revisit user fee for revisit surveys.  

Code of Federal Regulations, 2011 CFR

... false Revisit user fee for revisit surveys. 488.30 Section 488.30 Public...CONTINUED) STANDARDS AND CERTIFICATION SURVEY, CERTIFICATION, AND ENFORCEMENT PROCEDURES...488.30 Revisit user fee for revisit surveys. (a) Definitions. As used...

2011-10-01

34

Effect of clozapine on white matter integrity in patients with schizophrenia: a diffusion tensor imaging study.  

PubMed

Several diffusion tensor imaging (DTI) studies have reported disturbed white matter integrity in various brain regions in patients with schizophrenia, whereas only a few studied the effect of antipsychotics on DTI measures. The aim of this study was to investigate the effect of 12 weeks of clozapine treatment on DTI findings in patients with schizophrenia, and to compare the findings with those in unaffected controls. The study included 16 patients with schizophrenia who were assessed with the Positive and Negative Syndrome Scale, a neurocognitive test battery, and DTI at baseline and 12 weeks after the initiation of clozapine treatment. Eight unaffected controls were assessed once with the neurocognitive test battery and DTI. Voxel-wise analysis of DTI data was performed via tract-based spatial statistics (TBSS). Compared with the control group, the patient group exhibited lower fractional anisotropy (FA) in 16 brain regions, including the bilateral superior longitudinal fasciculi, inferior fronto-occipital fasciculi, superior and inferior parietal lobules, cingulate bundles, cerebellum, middle cerebellar peduncles, and left inferior longitudinal fasciculus, whereas the patients had higher FA in six regions, including the right parahippocampus, left anterior thalamic radiation, and right posterior limb of the internal capsule before clozapine treatment. After 12 weeks of treatment with clozapine, white matter FA was increased in widespread brain regions. In two of the regions where FA had initially been lower in patients compared with controls (left inferior fronto-occipital fasciculus and superior parietal lobule), clozapine appeared to increase FA. An improvement in semantic fluency was correlated with the increase in FA value in the left inferior fronto-occipital fasciculus. An increase in FA following 12 weeks of treatment with clozapine suggests that this treatment alters white matter microstructural integrity in patients with schizophrenia previously treated with typical and/or atypical antipsychotics and, in some locations, reverses a previous deficit. PMID:25012780

Ozcelik-Eroglu, Elcin; Ertugrul, Aygun; Oguz, Kader Karli; Has, Arzu Ceylan; Karahan, Sevilay; Yazici, Mumin Kazim

2014-09-30

35

Network Nation Revisited  

NSDL National Science Digital Library

The Network Nation Revisited" is an analysis of the predictions made by Hiltz and Turoff in _The Network Nation_, one of the seminal texts (published in 1978) in the field of Computer Mediated Communications.

36

"Sony Revisited," Revisited Another look at the paper that presaged  

E-print Network

that Sony took the staple-article doctrine of patent law as a model for its copyright safe-harbor rule"Sony Revisited," Revisited Another look at the paper that presaged Grokster and inducement of this paper is available at http://digital-law-online.info/papers/lah/sony-revisited.htm August 10, 2005 Draft

Hollaar, Lee A.

37

Management development revisited  

Microsoft Academic Search

Provides reflection on the special issue. Revisits the questions: What is management development? Why is management development worthy of our attention? What is to be learnt and when? What are the most effective techniques? This issue has identified four types of management development (MD). Administrative MD is gained through the experience of long service. Dependent MD is grooming for promotion

Jaap Paauwe; Roger Williams

2001-01-01

38

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

39

Google Scholar revisited  

Microsoft Academic Search

Purpose – The purpose of this paper is to revisit Google Scholar. Design\\/methodology\\/approach – This paper discusses the strengths and weaknesses of Google Scholar. Findings – The Google Books project has given a massive and valuable boost to the already rich and diverse content of Google Scholar. The downside of the growth is that significant gaps remain for top ranking

Péter Jacsó

2008-01-01

40

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

41

Revisiting Teachers as Learners  

ERIC Educational Resources Information Center

This article revisits the concept of teachers as learners within the context of radical changes that have taken place within the education system in England over the past 25 years. The concept of "professional courage" is discussed and examined in relation to questions and issues raised by Paulo Freire in a series of letters to teachers (1997).…

Thomson, Liz

2008-01-01

42

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

43

Revisiting Bioaccumulation Criteria  

EPA Science Inventory

The objective of workgroup 5 was to revisit the B(ioaccumulation) criteria that are currently being used to identify POPs under the Stockholm Convention and PBTs under CEPA, TSCA, REACh and other programs. Despite the lack of a recognized definition for a B substance, we defined ...

44

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

45

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

46

Horizontal portion of arcuate fasciculus fibers track to pars opercularis, not pars triangularis, in right and left hemispheres: a DTI study.  

PubMed

The arcuate fasciculus (AF) is a white matter pathway traditionally considered to connect left Broca's area with posterior language zones. We utilized diffusion tensor imaging (DTI) in eight healthy subjects (5 M) to track pathways in the horizontal mid-portion of the AF (hAF) to subregions of Broca's area - pars triangularis (PTr) and pars opercularis (POp); and to ventral premotor cortex (vPMC) in the right and left hemispheres (RH, LH). These pathways have previously been studied in the LH, but not in the RH. Only 1/8 subjects showed fiber tracts between PTr and hAF in the RH (also, only 1/8 in the LH). In contrast to PTr, 5/8 subjects showed fiber tracts between POp and hAF in the RH (8/8 in the LH). Fiber tracts for vPMC were similar to those of POp, where 7/8 subjects showed fiber tracts between vPMC and hAF in the RH (8/8 in the LH). Our designated hAF could have included some of the superior longitudinal fasciculus (SLF) III, because it is difficult to separate the two fiber bundles. The SLF III has been previously reported to connect supramarginal gyrus with POp and vPMC in the LH. Thus, although the present DTI study showed almost no pathways between PTr and hAF in the RH (and in the LH), robust pathways were observed between POp and/or vPMC with hAF in the RH (and in LH). These results replicate previous studies for the LH, but are new, for the RH. They could contribute to better understanding of recovery in aphasia. PMID:20438853

Kaplan, Elina; Naeser, Margaret A; Martin, Paula I; Ho, Michael; Wang, Yunyan; Baker, Errol; Pascual-Leone, Alvaro

2010-08-15

47

Revisiting Dialogues and Monologues  

ERIC Educational Resources Information Center

In educational discourse dialogue tends to be viewed as being (morally) superior to monologue. When we look at them as basic forms of communication, we find that dialogue is a two-way, one-to-one form and monologue is a one-way, one-to-many form. In this paper I revisit the alleged (moral) superiority of dialogue. First, I problematize certain…

Kvernbekk, Tone

2012-01-01

48

Patterns of Dysgraphia in Primary Progressive Aphasia Compared to Post-Stroke Aphasia  

PubMed Central

We report patterns of dysgraphia in participants with primary progressive aphasia that can be explained by assuming disruption of one or more cognitive processes or representations in the complex process of spelling. These patterns are compared to those described in participants with focal lesions (stroke). Using structural imaging techniques, we found that damage to the left extrasylvian regions, including the uncinate, inferior fronto-occipital fasciculus, and sagittal stratum (including geniculostriate pathway and inferior longitudinal fasciculus), as well as other deep white and grey matter structures, was significantly associated with impairments in access to orthographic word forms and semantics (with reliance on phonology-to-orthography to produce a plausible spelling in the spelling to dictation task). These results contribute not only to our understanding of the patterns of dysgraphia following acquired brain damage but also the neural substrates underlying spelling. PMID:22713396

Faria, Andreia V.; Crinion, Jenny; Tsapkini, Kyrana; Newhart, Melissa; Davis, Cameron; Cooley, Shannon; Mori, Susumu; Hillis, Argye E.

2013-01-01

49

The language connectome: new pathways, new concepts.  

PubMed

The field of the neurobiology of language is experiencing a paradigm shift in which the predominant Broca-Wernicke-Geschwind language model is being revised in favor of models that acknowledge that language is processed within a distributed cortical and subcortical system. While it is important to identify the brain regions that are part of this system, it is equally important to establish the anatomical connectivity supporting their functional interactions. The most promising framework moving forward is one in which language is processed via two interacting "streams"--a dorsal and ventral stream--anchored by long association fiber pathways, namely the superior longitudinal fasciculus/arcuate fasciculus, uncinate fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, and two less well-established pathways, the middle longitudinal fasciculus and extreme capsule. In this article, we review the most up-to-date literature on the anatomical connectivity and function of these pathways. We also review and emphasize the importance of the often overlooked cortico-subcortical connectivity for speech via the "motor stream" and associated fiber systems, including a recently identified cortical association tract, the frontal aslant tract. These pathways anchor the distributed cortical and subcortical systems that implement speech and language in the human brain. PMID:24342910

Dick, Anthony Steven; Bernal, Byron; Tremblay, Pascale

2014-10-01

50

Subcortical anatomy of the lateral association fascicles of the brain: A review.  

PubMed

Precise knowledge of the connectivities of the different white matter bundles is of great value for neuroscience research. Our knowledge of subcortical anatomy has improved exponentially during recent decades owing to the development of magnetic resonance diffusion tensor imaging tractography (DTI). Although DTI tractography has led to important progress in understanding white matter anatomy, the precise trajectory and cortical connections of the subcortical bundles remain poorly determined. The recent literature was extensively reviewed in order to analyze the trajectories and cortical terminations of the lateral association fibers of the brain.The anatomy of the following tracts is reviewed: superior longitudinal fasciculus, middle longitudinal fasciculus, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, frontal aslant tract, and vertical occipital fasciculus. The functional role of a tract can be inferred from its topography within the brain. Knowing the functional roles of the cortical areas connected by a certain bundle, it is possible to develop new insights into the putative functional properties of such connections. PMID:24453050

Martino, Juan; De Lucas, Enrique Marco

2014-05-01

51

White matter structural connectivity underlying semantic processing: evidence from brain damaged patients.  

PubMed

Widely distributed brain regions in temporal, parietal and frontal cortex have been found to be involved in semantic processing, but the anatomical connections supporting the semantic system are not well understood. In a group of 76 right-handed brain-damaged patients, we tested the relationship between the integrity of major white matter tracts and the presence of semantic deficits. The integrity of white matter tracts was measured by percentage of lesion voxels obtained in structural imaging and mean fractional anisotropy values obtained in diffusion tensor imaging. Semantic deficits were assessed by jointly considering the performance on three semantic tasks that vary in the modalities of input (visual and auditory stimuli) and output (oral naming and associative judgement). We found that the lesion volume and fractional anisotropy value of the left inferior fronto-occipital fasciculus, left anterior thalamic radiation, and left uncinate fasciculus significantly correlated with severity of impairment in all three semantic tasks. These associations remained significant even when we controlled for a wide range of potential confounding variables, including overall cognitive state, whole lesion volume, or type of brain damage. The effects of these three white matter tracts could not be explained by potential involvement of relevant grey matter, and were (relatively) specific to object semantic processing, as no correlation with performance on non-object semantic control tasks (oral repetition and number processing tasks) was observed. These results underscore the causal role of left inferior fronto-occipital fasciculus, left anterior thalamic radiation, and left uncinate fasciculus in semantic processing, providing direct evidence for (part of) the anatomical skeleton of the semantic network. PMID:23975453

Han, Zaizhu; Ma, Yujun; Gong, Gaolang; He, Yong; Caramazza, Alfonso; Bi, Yanchao

2013-10-01

52

Association of dorsal inferior frontooccipital fasciculus fibers in the deep parietal lobe with both reading and writing processes: a brain mapping study.  

PubMed

Alexia and agraphia are disorders common to the left inferior parietal lobule, including the angular and supramarginal gyri. However, it is still unclear how these cortical regions interact with other cortical sites and what the most important white matter tracts are in relation to reading and writing processes. Here, the authors present the case of a patient who underwent an awake craniotomy for a left inferior parietal lobule glioma using direct cortical and subcortical electrostimulation. The use of subcortical stimulation allowed identification of the specific white matter tracts associated with reading and writing. These tracts were found as portions of the dorsal inferior frontooccipital fasciculus (IFOF) fibers in the deep parietal lobe that are responsible for connecting the frontal lobe to the superior parietal lobule. These findings are consistent with previous diffusion tensor imaging tractography and functional MRI studies, which suggest that the IFOF may play a role in the reading and writing processes. This is the first report of transient alexia and agraphia elicited through intraoperative direct subcortical electrostimulation, and the findings support the crucial role of the IFOF in reading and writing. PMID:24655122

Motomura, Kazuya; Fujii, Masazumi; Maesawa, Satoshi; Kuramitsu, Shunichiro; Natsume, Atsushi; Wakabayashi, Toshihiko

2014-07-01

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

Fossil turbulence revisited  

E-print Network

A theory of fossil turbulence presented in the 11th Liege Colloquium on Marine turbulence is "revisited" in the 29th Liege Colloquium "Marine Turbulence Revisited". The Gibson (1980) theory applied universal similarity theories of turbulence and turbulent mixing to the vertical evolution of an isolated patch of turbulence in a stratified fluid as it is constrained and fossilized by buoyancy forces. Towed oceanic microstructure measurements of Schedvin (1979) confirmed the predicted universal constants. Universal constants, spectra, hydrodynamic phase diagrams (HPDs) and other predictions of the theory have been reconfirmed by a wide variety of field and laboratory observations. Fossil turbulence theory has many applications; for example, in marine biology, laboratory and field measurements suggest phytoplankton species with different swimming abilities adjust their growth strategies differently by pattern recognition of several days of turbulence-fossil-turbulence dissipation and persistence times above threshold values, signaling a developing surface layer sea change. In cosmology, self-gravitational structure masses are interpreted as fossils of primordial hydrodynamic states.

Carl H. Gibson

1999-04-19

55

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

56

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

57

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

58

L134N Revisited  

NASA Astrophysics Data System (ADS)

L134N (also known as L183) is a very cold, starless and nearby dark cloud which has attracted much attention from the astrochemists in the past. They have been using it as an oxygen-rich reference to test their models in parallel with TMC-1, the other, but carbon-rich, reference. However, our knowledge of the cloud temperature, structure, and various species abundances has relied for a long time largely on the work by Swade (1987a, 1987b) which suffers from low signal-to-noise C18O and CS maps and limited excitation analysis. This work has been recently repeated and improved by Dickens et al. (2000) but they still lack adequate surface coverage, higher rotational lines of important species and comparison with the dust. While FIRST will probably find many new species in this cloud, it is time to revisit completely this source in order to interpret correctly the FIRST results to come. We have thus made a complete survey of several transitions of CO, 13CO, C18O, C17O, CS, C34S, SO and 34SO species with the NRAO 12-m and CSO 10-m together with maps of the dust from ISO and SCUBA to assess the fundamental properties of this cloud. Preliminary results are reported here.

Pagani, L.; Pardo-Carrion, J. R.; Stepnik, B.

2001-07-01

59

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 of the Internet" #12;unique identifiers basis for accurate routing of information (TCP/IP) IP-blocks managed

Schweik, Charles M.

60

PSOS Revisited Peter G. Neumann  

E-print Network

PSOS Revisited Peter G. Neumann Computer Science Laboratory SRI International Menlo Park CA 94025 This paper provides a retrospective view of the design of SRI's Provably Secure Operating System (PSOS), a for- mally specified tagged-capability hierarchical system ar- chitecture. It examines PSOS

Neumann, Peter G.

61

Radiolytic Cryovolcanism Revisited  

NASA Astrophysics Data System (ADS)

Active geysers of water vapor and ice grains from the south pole of Enceladus are not yet definitively explained in terms of energy sources and processes. Other instances of hot (Io) and cold (Mars, Triton) volcanism beyond Earth are known if not fully understood. We revisit, in comparison to other models, the 'Old Faithful' theory of radiolytic gas-driven cryovolcanism first proposed by Cooper et al. [Plan. Sp. Sci. 2009]. In the energetic electron irradiation environment of Enceladus within Saturn's magnetosphere, a 10-percent duty cycle could be maintained for current geyser activity driven by gases from oxidation of ammonia to N2 and methane to CO2 in the thermal margins of a south polar sea. Much shorter duty cycles down to 0.01 percent would be required to account for thermal power output up to 16 GW, Steady accumulation of oxidant energy over four billion years could have powered all Enceladus emissions over the past four hundred thousand to four hundred million years. There could be separate energy sources driving mass flow and thermal emission over vastly different time scales. Since episodic tidal dissipation on 10 Myr time scales at 0.1 - 1 Gyr intervals [O'Neill and Nimmo, Nature 2010], and thus duty cycles 1 - 10 percent, could heat the polar sea to the current level, the radiolytic energy source could easily power and modulate the geyser mass flow on million-year time scales. Maximum thermal emission temperature 223 K [Abramov and Spencer, Icarus 2009] hints at thermal buffering in the basal and vent wall layers by a 1:1 H2O:H2O2 radiolytic eutectic, assuming deep ice crust saturation with H2O2 from long cumulative surface irradiation and downward ice convection. Due to density stratification the peroxide eutectic and salt water layers could separate, so that the denser peroxide layer (1.2 g/cc) descends to the polar sea while the lighter salt water (1.05 g/cc) rises along separate channels. Methane reservoirs could be found dissolved into the polar sea, or else trapped in hydrates [Kieffer et al., Science 2006] along flow paths and at the walls of the polar sea at surface depths below 20 km [Fortes, Icarus 2007]. Driver gas production for cryovolcanism could occur wherever these two layers come into contact under requisite temperature and pressure conditions, e.g. from 220 K and 10 bar at the 10-km basal layer of the overlying ice crust to 647 K and 220 bars at the liquid water limit, above the core-mantle boundary at 460 bars [Fortes, Icarus 2007]. We expect H2O2 oxidation to ignite at high temperatures but metallic minerals could catalyze reactions at lower temperatures nearer the basal layer. Pressure effects on oxidation rates are uncertain. Definitive modeling of Enceladus cryovolcanism likely involves synthesis of key processes from multiple models: Cold Faithful [Porco et al., Science 2006], Frigid Faithful [Keiffer et al., Science 2006], Frothy Faithful [Fortes, Icarus 2007], Old Faithful, and 'Perrier Ocean' recirculation [Matson et al., Icarus 2012].

Cooper, J. F.; Cooper, P. D.; Sittler, E. C.; Wesenberg, R. P.

2013-12-01

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; Muller, 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

Lithium and GSK3-? Promoter Gene Variants Influence White Matter Microstructure in Bipolar Disorder  

PubMed Central

Lithium is the mainstay for the treatment of bipolar disorder (BD) and inhibits glycogen synthase kinase 3-? (GSK3-?). The less active GSK3-? promoter gene variants have been associated with less detrimental clinical features of BD. GSK3-? gene variants and lithium can influence brain gray matter structure in psychiatric conditions. Diffusion tensor imaging (DTI) measures of white matter (WM) integrity showed widespred disruption of WM structure in BD. In a sample of 70 patients affected by a major depressive episode in course of BD, we investigated the effect of ongoing long-term lithium treatment and GSK3-? promoter rs334558 polymorphism on WM microstructure, using DTI and tract-based spatial statistics with threshold-free cluster enhancement. We report that the less active GSK3-? rs334558*C gene-promoter variants, and the long-term administration of the GSK3-? inhibitor lithium, were associated with increases of DTI measures of axial diffusivity (AD) in several WM fiber tracts, including corpus callosum, forceps major, anterior and posterior cingulum bundle (bilaterally including its hippocampal part), left superior and inferior longitudinal fasciculus, left inferior fronto-occipital fasciculus, left posterior thalamic radiation, bilateral superior and posterior corona radiata, and bilateral corticospinal tract. AD reflects the integrity of axons and myelin sheaths. We suggest that GSK3-? inhibition and lithium could counteract the detrimental influences of BD on WM structure, with specific benefits resulting from effects on specific WM tracts contributing to the functional integrity of the brain and involving interhemispheric, limbic, and large frontal, parietal, and fronto-occipital connections. PMID:22990942

Benedetti, Francesco; Bollettini, Irene; Barberi, Ignazio; Radaelli, Daniele; Poletti, Sara; Locatelli, Clara; Pirovano, Adele; Lorenzi, Cristina; Falini, Andrea; Colombo, Cristina; Smeraldi, Enrico

2013-01-01

65

Revisiting the Schrodinger probability current  

E-print Network

We revisit the definition of the probability current for the Schrodinger equation. First, we prove that the Dirac probability currents of stationary wave functions of the hydrogen atom and of the isotrop harmonic oscillator are not nil and correspond to a circular rotation of the probability. Then, we recall how it is necessary to add to classical Pauli and Schrodinger currents, an additional spin-dependant current, the Gordan current. Consequently, we get a circular probability current in the Schrodinger approximation for the hydrogen atom and the isotrop harmonic oscillator.

Michel Gondran; Alexandre Gondran

2003-04-08

66

Cortico-Cortical, Cortico-Striatal, and Cortico-Thalamic White Matter Fiber Tracts Generated in the Macaque Brain via Dynamic Programming  

PubMed Central

Abstract 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

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

67

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

68

Personality-relationship transactions revisited.  

PubMed

The transactional paradigm states that people create, maintain, and change their environments according to their personalities. At the same time, the environment reacts back on personality. As social relationships are part of an individual's environment, this likewise implies that there are reciprocal transactions between personality and relationships. However, earlier studies have concluded that adult personality traits are so stable that they have a stronger effect on later relationships, but that relationship effects on personality are negligible. In this article, we contend that personality-relationship transactions should be revisited. We submit that the relative powers of personality versus relationship effects depend on the type of life transition during which the effects take place: Relationship effects on personality development are more likely to emerge in the context of rather normative and highly scripted life transitions, whereas personality effects on relationship development are more likely to occur in the context of rather non-normative life transitions that are less regulated by social expectations. We illustrate these assumptions with examples from our own work and other findings reported in the literature. Furthermore, we theorize that effects of personality-relationship transactions on health also vary with the normativeness of the eliciting life transition. PMID:23927445

Neyer, Franz J; Mund, Marcus; Zimmermann, Julia; Wrzus, Cornelia

2014-12-01

69

Pharmacy School Survey Standards Revisited  

PubMed Central

In a series of 3 papers on survey practices published from 2008 to 2009, the editors of the American Journal of Pharmaceutical Education presented guidelines for reporting survey research, and these criteria are reflected in the Author Instructions provided on the Journal’s Web site. This paper discusses the relevance of these criteria for publication of survey research regarding pharmacy colleges and schools. In addition, observations are offered about surveying of small "universes" like that comprised of US colleges and schools of pharmacy. The reason for revisiting this issue is the authors’ concern that, despite the best of intentions, overly constraining publication standards might discourage research on US colleges and schools of pharmacy at a time when the interest in the growth of colleges and schools, curricular content, clinical education, competence at graduation, and other areas is historically high. In the best traditions of academia, the authors share these observations with the community of pharmacy educators in the hope that the publication standards for survey research about US pharmacy schools will encourage investigators to collect and disseminate valuable information. PMID:23459404

Barnett, Mitchell J.; Lenth, Russell V.; Knapp, Katherine K.

2013-01-01

70

Attention to Form and Meaning Revisited  

ERIC Educational Resources Information Center

The present study revisited the issue of simultaneous attention to form and meaning from a methodological perspective that addressed several potential methodological issues of previous research in this strand of inquiry. Seventy-two second-semester-level participants were randomly assigned to one of five experimental groups, including a control,…

Leow, Ronald P.; Hsieh, Hui-Chen; Moreno, Nina

2008-01-01

71

Revisiting the Regenerative Possibilities of Ortiz  

ERIC Educational Resources Information Center

The author of this article revisits Simon Ortiz's poem, "From Sand Creek," in which the latter can in so few words convey both the horrific tragedy of conquest and colonization, while at the same time find a space for possibility, a means for recovery that is never about forgetting but always occurs as a kind of recuperative remembering. Ortiz…

Duques, Matthew

2004-01-01

72

REVISITING COMMONS – ARE COMMON PROPERTY REGIMES IRRATIONAL?  

Microsoft Academic Search

This paper revisits the debate about communal management of natural resources and brings together various issues confronting it. Much of the criticism against common property regimes stems from an incorrect modeling of a common property situation, and misunderstandings about the terms and their wrong usage. Models of collective action (Hardin’s tragedy of the Commons, Olson’s Logic of Collective Action, and

Lubna Hasan

2002-01-01

73

Revisiting link privacy in social networks  

Microsoft Academic Search

In this paper, we revisit the problem of the link privacy attack in online social networks. In the link privacy attack, it turns out that by bribing or compromising a small number of nodes (users) in the social network graph, it is possible to obtain complete link information for a much larger fraction of other non-bribed nodes in the graph.

Suhendry Effendy; Roland H. C. Yap; Felix Halim

2012-01-01

74

IN THIS ISSUE Light Signaling Revisited  

E-print Network

IN THIS ISSUE Light Signaling Revisited Plants respond to light in a myriad of ways. Between light- genesis and the control of flowering time. More than 50 years ago, Harry Borthwick and colleagues the pigment responsible for this effect, which they named phyto- chrome, and also described its role in seed

Schäfer, Eberhard

75

Modeling skin permeation revisited Gabriel Wittum  

E-print Network

Modeling skin permeation revisited Gabriel Wittum Computing diffusion through human skin is usually into the diffusion process and yielded results about the permeation paths. After starting with simple two dimensional were made a decade ago, yielding new insight into permeation pathways through human skin, which were

Hackbusch, Wolfgang

76

Broadcast Flooding Revisited: Survivability and Latency  

E-print Network

Broadcast Flooding Revisited: Survivability and Latency Petteri Mannersalo VTT Technical Research University Email: riedi@rice.edu Abstract--This paper addresses the dynamics of broadcast flooding in random wireless ad hoc networks. In particular, we study the subset of nodes covered by a flood as well as timing

Riedi, Rudolf H.

77

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

78

Quantum Mechanics Revisited Jean Claude Dutailly  

E-print Network

Quantum Mechanics Revisited Jean Claude Dutailly Paris (France) August 20, 2014 Abstract The purpose of the paper is to study the foundations of the main axioms of Quantum Mechanics. From a general a new theoretical foundation. ii) The quantum mechanics (QM) which is presented in all the books

Boyer, Edmond

79

Diagnosis as Planning Revisited Shirin Sohrabi  

E-print Network

Diagnosis as Planning Revisited Shirin Sohrabi Department of Computer Science University of Toronto of diagnosis to deal with the case of incomplete information, and rich preferences. We also explore the use classes of diagnosis problems, we provide both proof of concept and benchmark experiments, the latter

McIlraith, Sheila

80

Declarative diagnosis revisited Marco Comini, Giorgio Levi  

E-print Network

Declarative diagnosis revisited Marco Comini, Giorgio Levi diagnosis methods to the diagnosis w.r.t. compu* *ted answers. We show that absence of uncovered-down and in a bottom-up styl* *e. Keywords: Declarative diagnosis, Verification, Semantics, Debugging 1

Comini, Marco

81

Panel: The Insider Problem Revisited Matt Bishop  

E-print Network

Panel: The Insider Problem Revisited Matt Bishop Dept. of Computer Science University of California at Davis Davis, CA 95616-8562 +1 (530)752-8060 bishop@cs.ucdavis.edu ABSTRACT The "insider problem as different assumptions. 1. INTRODUCTION The "insider threat" or "insider problem" is cited as the most

Bishop, Matt

82

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.

83

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

84

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

85

Levine's motivic comparison theorem revisited Florian Ivorra  

E-print Network

Levine's motivic comparison theorem revisited Florian Ivorra 5th July 2006 Abstract For a #12;eld of characteristic zero Levine has proved in [12, Part I, Ch. VI, 2.5.5] that the triangulated tensor categories that the strategy of Levine's proof can also be applied on every perfect #12;eld to the categories of triangulated

86

Levine's motivic comparison theorem revisited Florian Ivorra  

E-print Network

Levine's motivic comparison theorem revisited Florian Ivorra Levine has proved in [12, Part I, Ch. V* *I, 2.5.5] that the triangulated tensor categories that the strategy of Levine's proof can also be applied on every perfect field to the categories

87

Levine's motivic comparison theorem revisited Florian Ivorra  

E-print Network

Levine's motivic comparison theorem revisited Florian Ivorra 5th July 2006 Abstract For a field of characteristic zero Levine has proved in [12, Part I, Ch. VI, 2.5.5] that the triangulated tensor categories that the strategy of Levine's proof can also be applied on every perfect field to the categories of triangulated

88

Sony Revisited: A new look at contributory copyright infringement*  

E-print Network

of the copyright, and therefore the right to determine the business model for its distribution to the publicSony Revisited: A new look at contributory copyright infringement* Lee A. Hollaar Professor, School at http://digital-law-online.info/papers/lah/sony-revisited.htm Introduction Digital technology

Hollaar, Lee A.

89

RED Revisited Tuan Anh Trinh and Sandor Molnar  

E-print Network

RED Revisited Tuan Anh Trinh and S´andor Moln´ar High Speed Networks Laboratory Department- ternet is RED. However, research results on RED perfor- mance are highly mixed, especially in the field of tuning its parameters. In this paper, we revisit some features in RED and study them in greater details

Molnár, Sándor

90

RED Revisited Tuan Anh Trinh and Sandor Molnar  

E-print Network

RED Revisited Tuan Anh Trinh and S�andor Moln�ar High Speed Networks Laboratory Department� ternet is RED. However, research results on RED perfor� mance are highly mixed, especially in the field of tuning its parameters. In this paper, we revisit some features in RED and study them in greater details

Molnár, Sándor

91

A drift homogenization problem revisited Marc BRIANE Patrick GERARD  

E-print Network

A drift homogenization problem revisited Marc BRIANE Patrick G´ERARD INSA de Rennes Universit Abstract This paper revisits a homogenization problem studied by L. Tartar related to a tridi- mensional method. A new method in the context of homogenization theory is proposed. It is based on a parametrix

Paris-Sud XI, Université de

92

Revisiting the North Atlantic Oscillation Rodwell et al.1  

E-print Network

Revisiting the North Atlantic Oscillation Rodwell et al.1 use an atmospheric general circulation in the wintertime North Atlantic Oscillation (NAO) observed over the past 50 years. They reduce internal atmospheric WEBSITE. IT CAN BE CITED AS: Osborn TJ (1999) Revisiting the North Atlantic Oscillation. [http

Osborn, Tim

93

Transient and secular radioactive equilibrium revisited  

E-print Network

The two definitions of radioactive equilibrium are revisited in this paper. The terms activity equilibrium and effective life equilibrium are proposed to take the place of currently used terms transient equilibrium and secular equilibrium. The proposed new definitions have the advantage of providing a clearer physics meaning. Besides the well known instant activity equilibrium, another class of exact effective life-time equilibrium is also discussed in this letter.

Zhang, Qinghui; Amols, Howard

2014-01-01

94

Lifelong bilingualism contributes to cognitive reserve against white matter integrity declines in aging.  

PubMed

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

2013-11-01

95

Brain structures associated with executive functions during everyday events in a non-clinical sample.  

PubMed

Executive functions involve control processes such as goal-oriented planning, flexible strategy generation, sustaining set maintenance, self-monitoring, and inhibition. Executive functions during everyday events (EFEEs) are distinct from those measured under laboratory settings; the former can be severely impaired while the latter remain intact. Non-routine everyday problems due to executive dysfunctions affect individual functioning in everyday life and are of great clinical interest. Despite the importance of anatomical bases underlying better EFEEs, such bases have never been investigated among non-clinical samples. Using voxel-based morphometry to measure regional gray matter volume (rGMV) and regional white matter volume (rWMV) and diffusion tensor imaging to determine fractional anisotropy values, we identified the anatomical correlates of better EFEEs using the Dysexecutive Questionnaire in 303 normal young subjects (168 men and 135 women). Better EFEEs were associated with a smaller rGMV in the orbitofrontal cortex (OFC) spread across Brodmann areas (BA) 25, 11, and 12 and larger rWMV in the WM area of OFC adjacent to BA 11. Furthermore, individual EFEEs were positively associated with rWMV in the temporal areas, primarily the inferior longitudinal fasciculus and inferior fronto-occipital fasciculus, the latter of which connects OFC and posterior regions. Thus, our findings suggest that brain structures involving OFC, together with other regions, contribute to the maintenance of effective EFEEs among non-clinical subjects. PMID:22851058

Takeuchi, Hikaru; Taki, Yasuyuki; Sassa, Yuko; Hashizume, Hiroshi; Sekiguchi, Atsushi; Fukushima, Ai; Kawashima, Ryuta

2013-07-01

96

Facial affect recognition linked to damage in specific white matter tracts in traumatic brain injury.  

PubMed

Emotional processing deficits have recently been identified in individuals with traumatic brain injury (TBI), specifically in the domain of facial affect recognition. However, the neural networks underlying these impairments have yet to be identified. In the current study, 42 individuals with moderate to severe TBI and 23 healthy controls performed a task of facial affect recognition (Facial Emotion Identification Test (FEIT)) in order to assess their ability to identify and discriminate six emotions: happiness, sadness, anger, surprise, shame, and fear. These individuals also underwent structural neuroimaging including diffusion tensor imaging to examine white matter (WM) integrity. Correlational analyses were performed to determine where in the brain WM damage was associated with performance on the facial affect recognition task. Reduced performance on the FEIT was associated with reduced WM integrity (fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity) in the inferior longitudinal fasciculus and inferior-fronto-occipital fasciculus in individuals with TBI. Poor performance on the task was additionally associated with reduced gray matter (GM) volume in lingual gyrus and parahippocampal gyrus. The results implicate a pattern of WM and GM damage in TBI that may play a role in emotional processing impairments. PMID:25223759

Genova, Helen M; Rajagopalan, Venkateswaran; Chiaravalloti, Nancy; Binder, Allison; Deluca, John; Lengenfelder, Jeannie

2015-02-01

97

White Matter Integrity Predicts Delay Discounting Behavior in 9- to 23-Year-Olds: A Diffusion Tensor Imaging Study  

PubMed Central

Healthy participants (n = 79), ages 9–23, completed a delay discounting task assessing the extent to which the value of a monetary reward declines as the delay to its receipt increases. Diffusion tensor imaging (DTI) was used to evaluate how individual differences in delay discounting relate to variation in fractional anisotropy (FA) and mean diffusivity (MD) within whole-brain white matter using voxel-based regressions. Given that rapid prefrontal lobe development is occurring during this age range and that functional imaging studies have implicated the prefrontal cortex in discounting behavior, we hypothesized that differences in FA and MD would be associated with alterations in the discounting rate. The analyses revealed a number of clusters where less impulsive performance on the delay discounting task was associated with higher FA and lower MD. The clusters were located primarily in bilateral frontal and temporal lobes and were localized within white matter tracts, including portions of the inferior and superior longitudinal fasciculi, anterior thalamic radiation, uncinate fasciculus, inferior fronto-occipital fasciculus, corticospinal tract, and splenium of the corpus callosum. FA increased and MD decreased with age in the majority of these regions. Some, but not all, of the discounting/ DTI associations remained significant after controlling for age. Findings are discussed in terms of both developmental and age-independent effects of white matter organization on discounting behavior. PMID:18767918

Olson, Elizabeth A.; Collins, Paul F.; Hooper, Catalina J.; Muetzel, Ryan; Lim, Kelvin O.; Luciana, Monica

2014-01-01

98

Thalamo-cortical connectivity in children born preterm mapped using probabilistic magnetic resonance tractography.  

PubMed

Our aim was to investigate the feasibility of studying white matter tracts and connections between the thalamus and the cortex in 2-year-old infants who were born preterm by probabilistic magnetic resonance (MR) tractography. Using this approach, we were able to visualize and quantify connectivity distributions in a number of white matter tracts, including the corticospinal tracts, optic radiations, fibers of the genu and splenium of the corpus callosum, superior longitudinal fasciculus and inferior fronto-occipital fasciculus, and to map the distribution within thalamus of fibers connecting to specific cortical regions. In eleven infants with no MR evidence of focal cerebral lesions and appropriate neurodevelopment as shown by general quotient (GQ) scores above 100, we mapped cortical connections to the thalamus that appeared similar to those reported in adults. However, in a proof-of-principle experiment, we examined one further child with marked white matter abnormalities and found that the volume and pattern of thalamo-cortical connections were severely disrupted. This technique promises to be a useful tool for assessing connectivity in the developing brain and in infants with lesions. PMID:17174575

Counsell, Serena J; Dyet, Leigh E; Larkman, David J; Nunes, Rita G; Boardman, James P; Allsop, Joanna M; Fitzpatrick, Julie; Srinivasan, Latha; Cowan, Frances M; Hajnal, Joseph V; Rutherford, Mary A; Edwards, A David

2007-02-01

99

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

100

Emerging structure-function relations in the developing face processing system.  

PubMed

To evaluate emerging structure-function relations in a neural circuit that mediates complex behavior, we investigated age-related differences among cortical regions that support face recognition behavior and the fiber tracts through which they transmit and receive signals using functional neuroimaging and diffusion tensor imaging. In a large sample of human participants (aged 6-23 years), we derived the microstructural and volumetric properties of the inferior longitudinal fasciculus (ILF), the inferior fronto-occipital fasciculus, and control tracts, using independently defined anatomical markers. We also determined the functional characteristics of core face- and place-selective regions that are distributed along the trajectory of the pathways of interest. We observed disproportionately large age-related differences in the volume, fractional anisotropy, and mean and radial, but not axial, diffusivities of the ILF. Critically, these differences in the structural properties of the ILF were tightly and specifically linked with an age-related increase in the size of a key face-selective functional region, the fusiform face area. This dynamic association between emerging structural and functional architecture in the developing brain may provide important clues about the mechanisms by which neural circuits become organized and optimized in the human cortex. PMID:23765156

Suzanne Scherf, K; Thomas, Cibu; Doyle, Jaime; Behrmann, Marlene

2014-11-01

101

Altered white matter microstructure is associated with social cognition and psychotic symptoms in 22q11.2 microdeletion syndrome  

PubMed Central

22q11.2 Microdeletion Syndrome (22q11DS) is a highly penetrant genetic mutation associated with a significantly increased risk for psychosis. Aberrant neurodevelopment may lead to inappropriate neural circuit formation and cerebral dysconnectivity in 22q11DS, which may contribute to symptom development. Here we examined: (1) differences between 22q11DS participants and typically developing controls in diffusion tensor imaging (DTI) measures within white matter tracts; (2) whether there is an altered age-related trajectory of white matter pathways in 22q11DS; and (3) relationships between DTI measures, social cognition task performance, and positive symptoms of psychosis in 22q11DS and typically developing controls. Sixty-four direction diffusion weighted imaging data were acquired on 65 participants (36 22q11DS, 29 controls). We examined differences between 22q11DS vs. controls in measures of fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD), using both a voxel-based and region of interest approach. Social cognition domains assessed were: Theory of Mind and emotion recognition. Positive symptoms were assessed using the Structured Interview for Prodromal Syndromes. Compared to typically developing controls, 22q11DS participants showed significantly lower AD and RD in multiple white matter tracts, with effects of greatest magnitude for AD in the superior longitudinal fasciculus. Additionally, 22q11DS participants failed to show typical age-associated changes in FA and RD in the left inferior longitudinal fasciculus. Higher AD in the left inferior fronto-occipital fasciculus (IFO) and left uncinate fasciculus was associated with better social cognition in 22q11DS and controls. In contrast, greater severity of positive symptoms was associated with lower AD in bilateral regions of the IFO in 22q11DS. White matter microstructure in tracts relevant to social cognition is disrupted in 22q11DS, and may contribute to psychosis risk.

Jalbrzikowski, Maria; Villalon-Reina, Julio E.; Karlsgodt, Katherine H.; Senturk, Damla; Chow, Carolyn; Thompson, Paul M.; Bearden, Carrie E.

2014-01-01

102

Revisiting Future Dangerousness Revisited: Response to DeLisi and Munoz  

Microsoft Academic Search

In a recently published article in this journal titled “Future Dangerousness Revisited,” DeLisi and Munoz (2003) offered a number of findings regarding the major disciplinary and violent misconduct of inmates in the Arizona Department of Corrections (ADOC). Most prominently, they opined that their findings demonstrated that death row inmates are more dangerous than other inmate groups. The methodology and analysis

Mark D. Cunningham; Jon R. Sorensen; Thomas J. Reidy

2004-01-01

103

Polynomial chaotic inflation in supergravity revisited  

NASA Astrophysics Data System (ADS)

We revisit a polynomial chaotic inflation model in supergravity which we proposed soon after the Planck first data release. Recently some issues have been raised in Ref. [12], concerning the validity of our polynomial chaotic inflation model. We study the inflaton dynamics in detail, and confirm that the inflaton potential is very well approximated by a polynomial potential for the parameters of our interest in any practical sense, and in particular, the spectral index and the tensor-to-scalar ratio can be estimated by single-field approximation. This justifies our analysis of the polynomial chaotic inflation in supergravity.

Nakayama, Kazunori; Takahashi, Fuminobu; Yanagida, Tsutomu T.

2014-10-01

104

Polynomial Chaotic Inflation in Supergravity Revisited  

E-print Network

We revisit a polynomial chaotic inflation model in supergravity which we proposed soon after the Planck first data release. Recently some issues have been raised in Ref.[12], concerning the validity of our polynomial chaotic inflation model. We study the inflaton dynamics in detail, and confirm that the inflaton potential is very well approximated by a polynomial potential for the parameters of our interest in any practical sense, and in particular, the spectral index and the tensor-to-scalar ratio can be estimated by single-field approximation. This justifies our analysis of the polynomial chaotic inflation in supergravity.

Kazunori Nakayama; Fuminobu Takahashi; Tsutomu T. Yanagida

2014-07-26

105

Polynomial Chaotic Inflation in Supergravity Revisited  

E-print Network

We revisit a polynomial chaotic inflation model in supergravity which we proposed soon after the Planck first data release. Recently some issues have been raised in Ref.[12], concerning the validity of our polynomial chaotic inflation model. We study the inflaton dynamics in detail, and confirm that the inflaton potential is very well approximated by a polynomial potential for the parameters of our interest in any practical sense, and in particular, the spectral index and the tensor-to-scalar ratio can be estimated by single-field approximation. This justifies our analysis of the polynomial chaotic inflation in supergravity.

Nakayama, Kazunori; Yanagida, Tsutomu T

2014-01-01

106

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

107

Delta potentials revisited via Fourier transform  

E-print Network

The problem of bound states in delta potentials is revisited by means of Fourier transform approach. The problem in a simple delta potential sums up to solve an algebraic equation of degree one for the Fourier transform of the eigenfunction and the problem for more than one delta function also reveals itself to be a simple matter. Quite differently from direct methods, no knowledge about the jump discontinuity of the first derivative of the eigenfunction is required to determine the solution of the problem.

A. S. de Castro

2012-09-30

108

The Guinea-Bissau Family of Mycobacterium tuberculosis Complex Revisited  

E-print Network

The Guinea-Bissau Family of Mycobacterium tuberculosis Complex Revisited Ramona Groenheit1, 8 WHO Supranational TB Reference Laboratory, Tuberculosis and Mycobacteria Unit, Institut Pasteur de of the Mycobacterium tuberculosis complex that, although genotypically closely related, phenotypically demonstrates

Paris-Sud XI, Université de

109

CALCULUS REVISITED: AN INTRODUCTORY COURSE IN K. GRACE KENNEDY  

E-print Network

CALCULUS REVISITED: AN INTRODUCTORY COURSE IN MATLAB K. GRACE KENNEDY When beginning to think about of programming language. 1 #12;2 K. GRACE KENNEDY · the relationship between secant lines, the tangent line

Bigelow, Stephen

110

THE GEISSER-LEVINE METHOD REVISITED BRUNO KAHN  

E-print Network

THE GEISSER-LEVINE METHOD REVISITED BRUNO KAHN Abstract. We reformulate part of the arguments of T. Geisser and M. Levine computing motivic that the Geisser-Levine method can be applied generally to compare motivic cohomology with other

111

Measuring Hospital Quality Using Pediatric Readmission and Revisit Rates  

PubMed Central

OBJECTIVE: To assess variation among hospitals on pediatric readmission and revisit rates and to determine the number of high- and low-performing hospitals. METHODS: In a retrospective analysis using the State Inpatient and Emergency Department Databases from the Healthcare Cost and Utilization Project with revisit linkages available, we identified pediatric (ages 1–20 years) visits with 1 of 7 common inpatient pediatric conditions (asthma, dehydration, pneumonia, appendicitis, skin infections, mood disorders, and epilepsy). For each condition, we calculated rates of all-cause readmissions and rates of revisits (readmission or presentation to the emergency department) within 30 and 60 days of discharge. We used mixed logistic models to estimate hospital-level risk-standardized 30-day revisit rates and to identify hospitals that had performance statistically different from the group mean. RESULTS: Thirty-day readmission rates were low (<10.0%) for all conditions. Thirty-day rates of revisit to the inpatient or emergency department setting ranged from 6.2% (appendicitis) to 11.0% (mood disorders). Study hospitals (n = 958) had low condition-specific visit volumes (37.0%–82.8% of hospitals had <25 visits). The only condition with >1% of hospitals labeled as different from the mean on 30-day risk-standardized revisit rates was mood disorders (4.2% of hospitals [n = 15], range of hospital performance 6.3%–15.9%). CONCLUSIONS: We found that when comparing hospitals’ performances to the average, few hospitals that care for children are identified as high- or low-performers for revisits, even for common pediatric diagnoses, likely due to low hospital volumes. This limits the usefulness of condition-specific readmission or revisit measures in pediatric quality measurement. PMID:23979094

Vittinghoff, Eric; Asteria-Penaloza, Renee; Edwards, Jeffrey D.; Yazdany, Jinoos; Lee, Henry C.; Boscardin, W. John; Cabana, Michael D.; Dudley, R. Adams

2013-01-01

112

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

113

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

114

Revisiting monotop production at the LHC  

E-print Network

Scenarios of new physics where a single top quark can be produced in association with large missing energy (monotop) have been recently studied both from the theoretical point of view and by experimental collaborations. We revisit the originally proposed monotop setup by embedding the effective couplings of the top quark in an SU(2)L invariant formalism. We show that minimality selects one model for each of the possible production mechanisms: a scalar field coupling to a right-handed top quark and an invisible fermion when the monotop system is resonantly produced, and a vector field mediating the interactions of a dark sector to right-handed quarks for the non-resonant production mode. We study in detail constraints on the second class of scenarios, originating from contributions to standard single top processes when the mediator is lighter than the top quark and from the dark matter relic abundance when the mediator is heavier than the top quark.

Boucheneb, Idir; Deandrea, Aldo; Fuks, Benjamin

2014-01-01

115

Revisiting monotop production at the LHC  

E-print Network

Scenarios of new physics where a single top quark can be produced in association with large missing energy (monotop) have been recently studied both from the theoretical point of view and by experimental collaborations. We revisit the originally proposed monotop setup by embedding the effective couplings of the top quark in an SU(2)L invariant formalism. We show that minimality selects one model for each of the possible production mechanisms: a scalar field coupling to a right-handed top quark and an invisible fermion when the monotop system is resonantly produced, and a vector field mediating the interactions of a dark sector to right-handed quarks for the non-resonant production mode. We study in detail constraints on the second class of scenarios, originating from contributions to standard single top processes when the mediator is lighter than the top quark and from the dark matter relic abundance when the mediator is heavier than the top quark.

Idir Boucheneb; Giacomo Cacciapaglia; Aldo Deandrea; Benjamin Fuks

2014-07-28

116

Rotation and anisotropy of galaxies revisited  

E-print Network

The use of the tensor virial theorem (TVT) as a diagnostic of anisotropic velocity distributions in galaxies is revisited. The TVT provides a rigorous global link between velocity anisotropy, rotation and shape, but the quantities appearing in it are not easily estimated observationally. Traditionally use has been made of a centrally averaged velocity dispersion and the peak rotation velocity. Although this procedure cannot be rigorously justified, tests on model galaxies show that it works surprisingly well. With the advent of integral-field spectroscopy it is now possible to establish a rigorous connection between the TVT and observations. The TVT is reformulated in terms of sky-averages, and the new formulation is tested on model galaxies.

James Binney

2005-04-18

117

ALFVEN WAVES IN SHEAR FLOWS REVISITED  

SciTech Connect

We revisit our earlier study of the evolution of an initial propagating Alfven wave in a magnetic-field-aligned flow with a cross-field velocity shear. Our goal is to show how the Alfven wave drives up plasma density fluctuations which might be observed and serve as a signature of the presence of Alfven waves in regions such as the solar corona which are inaccessible to direct observations. Here, we introduce a new initial condition which takes into account the initial distortion of the streamlines by the Alfven wave, and we present new analytical results for the driven waves. We find that the density fluctuations of a properly placed linearly polarized Alfven wave in a shear flow are much smaller than we originally estimated.

Hollweg, Joseph V. [Space Science Center, Morse Hall, University of New Hampshire, Durham, NH 03824 (United States); Kaghashvili, Edisher Kh., E-mail: joe.hollweg@unh.edu [Atmospheric and Environmental Research, Inc., 131 Hartwell Avenue, Lexington, MA 02421 (United States)

2012-01-10

118

Revisiting a magneto-elastic strange attractor  

NASA Astrophysics Data System (ADS)

We revisit an early example of a nonlinear oscillator that exhibits chaotic motions when subjected to periodic excitation: the magneto-elastically buckled beam. In the paper of Moons and Holmes (1980) [1] magnetic field calculations were outlined but not carried through; instead the nonlinear forces responsible for creation of a two-well potential and buckling were fitted to a polynomial function after reduction to a single mode model. In the present paper we compute the full magnetic field and use it to approximate the forces acting on the beam, also using a single mode reduction. This provides a complete model that accurately predicts equilibria, bifurcations, and free oscillation frequencies of an experimental device. We also compare some periodic, transient and chaotic motions with those obtained by numerical simulations of the single mode model, further illustrating the rich dynamical behavior of this simple electromechanical system.

Tam, Jee Ian; Holmes, Philip

2014-03-01

119

Electron heating in capacitively coupled plasmas revisited  

NASA Astrophysics Data System (ADS)

We revisit the problem of electron heating in capacitively coupled plasmas (CCPs), and propose a method for quantifying the level of collisionless and collisional heating in plasma simulations. The proposed procedure, based on the electron mechanical energy conservation equation, is demonstrated with particle-in-cell simulations of a number of single and multi-frequency CCPs operated in regimes of research and industrial interest. In almost all cases tested, the total electron heating is comprised of collisional (ohmic) and pressure heating parts. This latter collisionless component is in qualitative agreement with the mechanism of electron heating predicted from the recent re-evaluation of theoretical models. Finally, in very electrically asymmetric plasmas produced in multi-frequency discharges, we observe an additional collisionless heating mechanism associated with electron inertia.

Lafleur, T.; Chabert, P.; Booth, J. P.

2014-06-01

120

Visser's massive graviton bimetric theory revisited  

SciTech Connect

A massive gravity theory was proposed by Visser in the late 1990s. This theory, based on a background metric b{sub {alpha}{beta}} and on an usual dynamical metric g{sub {alpha}{beta}} has the advantage of being free of ghosts as well as discontinuities present in other massive theories proposed in the past. In the present investigation, the equations of Visser's theory are revisited with particular care on the related conservation laws. It will be shown that a multiplicative factor is missing in the graviton tensor originally derived by Visser, which has no incidence on the weak field approach but becomes important in the strong field regime when, for instance, cosmological applications are considered. In this case, contrary to some previous claims found in the literature, we conclude that a nonstatic background metric is required in order to obtain a solution able to mimic the {Lambda}CDM cosmology.

Roany, Alain de; Chauvineau, Bertrand; Freitas Pacheco, Jose A. de [University of Nice-Sophia Antipolis, Observatoire de la Cote d'Azur, Laboratoire Cassiopee, BP 4229, Nice Cedex 4 (France)

2011-10-15

121

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

122

Revisiting light neutralino scenarios in the MSSM  

E-print Network

We revisit the case of a light neutralino LSP in the framework of the MSSM. We consider a model with eleven free parameters. We show that all scenarios where the annihilation of light neutralinos rely mainly on the exchange of a light pseudoscalar are excluded by direct detection searches and by Fermi measurements of the gamma-flux from dwarf spheroidal galaxies. On the other hand, we find scenarios with light sleptons that satisfy all collider and astroparticle physics constraints. In this case, the lower limit on the LSP mass is 12.6 GeV. We discuss how the parameter space of the model will be further probed by new physics searches at the LHC.

Daniel Albornoz Vasquez; Genevieve Belanger; Celine Boehm

2011-08-05

123

Revisiting light neutralino scenarios in the MSSM  

E-print Network

We revisit the case of a light neutralino LSP in the framework of the MSSM. We consider a model with eleven free parameters. We show that all scenarios where the annihilation of light neutralinos rely mainly on the exchange of a light pseudoscalar are excluded by direct detection searches and by Fermi measurements of the gamma-flux from dwarf spheroidal galaxies. On the other hand, we find scenarios with light sleptons that satisfy all collider and astroparticle physics constraints. In this case, the lower limit on the LSP mass is 12.6 GeV. We discuss how the parameter space of the model will be further probed by new physics searches at the LHC.

Vasquez, Daniel Albornoz; Boehm, Celine

2011-01-01

124

Individual structural differences in left inferior parietal area are associated with schoolchildrens' arithmetic scores  

PubMed Central

Arithmetic skill is of critical importance for academic achievement, professional success and everyday life, and childhood is the key period to acquire this skill. Neuroimaging studies have identified that left parietal regions are a key neural substrate for representing arithmetic skill. Although the relationship between functional brain activity in left parietal regions and arithmetic skill has been studied in detail, it remains unclear about the relationship between arithmetic achievement and structural properties in left inferior parietal area in schoolchildren. The current study employed a combination of voxel-based morphometry (VBM) for high-resolution T1-weighted images and fiber tracking on diffusion tensor imaging (DTI) to examine the relationship between structural properties in the inferior parietal area and arithmetic achievement in 10-year-old schoolchildren. VBM of the T1-weighted images revealed that individual differences in arithmetic scores were significantly and positively correlated with the gray matter (GM) volume in the left intraparietal sulcus (IPS). Fiber tracking analysis revealed that the forceps major, left superior longitudinal fasciculus (SLF), bilateral inferior longitudinal fasciculus (ILF) and inferior fronto-occipital fasciculus (IFOF) were the primary pathways connecting the left IPS with other brain areas. Furthermore, the regression analysis of the probabilistic pathways revealed a significant and positive correlation between the fractional anisotropy (FA) values in the left SLF, ILF and bilateral IFOF and arithmetic scores. The brain structure-behavior correlation analyses indicated that the GM volumes in the left IPS and the FA values in the tract pathways connecting left IPS were both related to children's arithmetic achievement. The present findings provide evidence that individual structural differences in the left IPS are associated with arithmetic scores in schoolchildren. PMID:24367320

Li, Yongxin; Hu, Yuzheng; Wang, Yunqi; Weng, Jian; Chen, Feiyan

2013-01-01

125

White Matter Hyperintensities, Exercise and Improvement in Gait Speed: Does the Type of Gait Rehabilitation Matter?  

PubMed Central

Background and Objectives White matter hyperintensities (WMH) on brain MRI are associated with cognitive and mobility impairment in older adults. We examined whether WMH in tracts in older adults with mobility impairment are linked to outcomes of gait rehabilitation interventions. Design A 12-week randomized controlled single-blind trial. Setting University-based mobility research laboratory. Participants Ambulatory adults aged 65 and older with mobility impairment. Intervention A conventional gait intervention focusing on walking, endurance, balance, and strength (WEBS, n=21) compared to a task-oriented intervention focused on timing and coordination of gait (TC, n=23). Measurements We measured self-paced gait speed over an instrumented walkway, pre and post intervention, and quantified WMH and brain volumes on pre-intervention brain MRI using an automated segmentation process. We overlaid a white matter tract atlas on the segmented images to measure tract WMH volumes and normalized WMH volumes to total brain volume. Aggregate WMH volumes in all white matter tracts and individual WMH volumes in specific longitudinal tracts (the superior longitudinal fasciculus, inferior longitudinal fasciculus and the fronto-occipital fasciculus) and cingulum were obtained. Results Gait speed gains in the TC group were of the same magnitude, independent of the WMH volume measures in all except the cingulum. However, in the WEBS group, gain in gait speed was smaller with greater overall tract WMH volumes (P<0.001) and with greater WMH volume in the three longitudinal tracts (P< 0.001 to 0.025). Conclusion Gains in gait speed with two types of gait rehabilitation are associated with individual differences in WMH. Task-oriented therapy that targets timing and coordination of gait may particularly benefit older adults with WMH in brain tracts that influence gait and cognition. PMID:23590257

Nadkarni, Neelesh K.; Studenski, Stephanie A.; Perera, Subashan; Rosano, Caterina; Aizenstein, Howard J.; Brach, Jennifer S.; VanSwearingen, Jessie M.

2013-01-01

126

Left hemisphere fractional anisotropy increase in noise-induced tinnitus: a diffusion tensor imaging (DTI) study of white matter tracts in the brain.  

PubMed

Diffusion tensor imaging (DTI) is a contemporary neuroimaging modality used to study connectivity patterns and microstructure of white matter tracts in the brain. The use of DTI in the study of tinnitus is a relatively unexplored methodology with no studies focusing specifically on tinnitus induced by noise exposure. In this investigation, participants were two groups of adults matched for etiology, age, and degree of peripheral hearing loss, but differed by the presence or absence (+/-) of tinnitus. It is assumed that matching individuals on the basis of peripheral hearing loss, allows for differentiating changes in white matter microstructure due to hearing loss from changes due to the effects of chronic tinnitus. Alterations in white matter tracts, using the fractional anisotropy (FA) metric, which measures directional diffusion of water, were quantified using tract-based spatial statistics (TBSS) with additional details provided by in vivo probabilistic tractography. Our results indicate that 10 voxel clusters differentiated the two groups, including 9 with higher FA in the group with tinnitus. A decrease in FA was found for a single cluster in the group with tinnitus. However, seven of the 9 clusters with higher FA were in left hemisphere thalamic, frontal, and parietal white matter. These foci were localized to the anterior thalamic radiations and the inferior and superior longitudinal fasciculi. The two right-sided clusters with increased FA were located in the inferior fronto-occipital fasciculus and superior longitudinal fasciculus. The only decrease in FA for the tinnitus-positive group was found in the superior longitudinal fasciculus of the left parietal lobe. PMID:24212050

Benson, Randall R; Gattu, Ramtilak; Cacace, Anthony T

2014-03-01

127

White matter integrity, language, and childhood onset schizophrenia  

PubMed Central

Background The heterogeneity of symptoms and cognitive deficits in schizophrenia can be explained by abnormal connectivity between brain regions. Childhood-onset schizophrenia (COS) is a particularly severe form of schizophrenia, with an onset during a key time period for both cerebral pruning and myelination. Methods Diffusion tensor images were acquired from 18 children and adolescents with COS and 25 controls. The COS group was divided into two sub-groups--one with linguistic impairment (LI) and the other without (NLI). The fractional anisotropy (FA), axial (AD), and radial diffusivity (RD) data from the two COS sub-groups were compared to each other and to the controls using tract-based spatial statistics (TBSS) analyses, which is a voxel-based method used to identify regions of white matter abnormalities. Results TBSS identified several regions in the left hemisphere where the LI group had increased AD and RD relative to the NLI and the control groups. These areas primarily localized to linguistic tracts: left superior longitudinal fasciculus and left inferior longitudinal fasciculus/inferior fronto-occipital fasciculus. Regions of increased RD overlapped regions of increased AD, with the former showing more pronounced effects. Conclusions Studies of adult-onset schizophrenia typically identify areas of higher RD but unchanged AD; however, normal development studies have shown that while RD decreases are pronounced over this age range, smaller decreases in AD can also be detected. The observed increases in both RD and AD suggest that developmental disturbances affecting the structural connectivity of these pathways are more severe in COS accompanied by severe linguistic impairments. PMID:22405729

Clark, Kristi; Narr, Katherine L.; O’Neill, Joseph; Levitt, Jennifer; Siddarth, Prabha; Phillips, Owen; Toga, Arthur; Caplan, Rochelle

2012-01-01

128

Evaluation of Diffusion-Tensor Imaging-Based Global Search and Tractography for Tumor Surgery Close to the Language System  

PubMed Central

Pre-operative planning and intra-operative guidance in neurosurgery require detailed information about the location of functional areas and their anatomo-functional connectivity. In particular, regarding the language system, post-operative deficits such as aphasia can be avoided. By combining functional magnetic resonance imaging and diffusion tensor imaging, the connectivity between functional areas can be reconstructed by tractography techniques that need to cope with limitations such as limited resolution and low anisotropic diffusion close to functional areas. Tumors pose particular challenges because of edema, displacement effects on brain tissue and infiltration of white matter. Under these conditions, standard fiber tracking methods reconstruct pathways of insufficient quality. Therefore, robust global or probabilistic approaches are required. In this study, two commonly used standard fiber tracking algorithms, streamline propagation and tensor deflection, were compared with a previously published global search, Gibbs tracking and a connection-oriented probabilistic tractography approach. All methods were applied to reconstruct neuronal pathways of the language system of patients undergoing brain tumor surgery, and control subjects. Connections between Broca and Wernicke areas via the arcuate fasciculus (AF) and the inferior fronto-occipital fasciculus (IFOF) were validated by a clinical expert to ensure anatomical feasibility, and compared using distance- and diffusion-based similarity metrics to evaluate their agreement on pathway locations. For both patients and controls, a strong agreement between all methods was observed regarding the location of the AF. In case of the IFOF however, standard fiber tracking and Gibbs tracking predominantly identified the inferior longitudinal fasciculus that plays a secondary role in semantic language processing. In contrast, global search resolved connections in almost every case via the IFOF which could be confirmed by probabilistic fiber tracking. The results show that regarding the language system, our global search is superior to clinically applied conventional fiber tracking strategies with results similar to time-consuming global or probabilistic approaches. PMID:23308093

Richter, Mirco; Zolal, Amir; Ganslandt, Oliver; Buchfelder, Michael; Nimsky, Christopher; Merhof, Dorit

2013-01-01

129

Predator-prey interactions, resource depression and patch revisitation  

USGS Publications Warehouse

Generalist predators may be confronted by different types of prey in different patches: sedentary and conspicuous, cryptic (with or without refugia), conspicuous and nonsocial, or conspicuous and social. I argue that, where encounter rates with prey are of most importance, patch revisitation should be a profitable tactic where prey have short 'recovery' times (conspicuous, nonsocial prey), or where anti-predator response (e.g. shoaling) may increase conspicuousness. Predictions are made for how temporal changes in prey encounter rates should affect revisit schedules and feeding rates for the 4 different prey types.

Erwin, R.M.

1989-01-01

130

The Infrared Spectrum of CH_5^+ Revisited  

NASA Astrophysics Data System (ADS)

The infrared spectrum of CH_5^+, originally collected and published over a decade ago, remains unassigned to this day owing to its complexity. CH_5^+ is a highly fluxional species that challenges the concept of molecular structure itself, and consequently the spectrum features no obvious patterns that would aid in assignment. Efforts toward extracting rotational energy level spacings using the four-line combination differences technique have been frustrated by the low precision of the spectrum, leading to a large number of coincidences in a combination differences analysis. Knowledge of energy level spacings could guide searches for its microwave spectrum, and consequently its detection in the interstellar medium where it is expected to be an important reactive species. We have revisited the infrared spectrum of CH_5^+ using Noise Immune Cavity-Enhanced Optical Heterodyne Velocity Modulation Spectroscopy (NICE-OHVMS) with a cw-OPO laser. By combining our spectrometer with an optical frequency comb, we can measure line centers with much greater precision and accuracy than previously possible. In this talk, we will discuss progress toward remeasurement of the previously-published lines with NICE-OHVMS, and the implications of greater precision and accuracy for the combination differences analysis.

Crabtree, Kyle N.; Hodges, James N.; McCall, Benjamin J.

2012-06-01

131

Double lunar swing-by orbits revisited  

NASA Astrophysics Data System (ADS)

The double lunar swing-by orbits are a special kind of orbits in the Earth-Moon system. These orbits repeatedly pass through the vicinity of the Moon and change their shapes due to the Moon's gravity. In the synodic frame of the circular restricted three-body problem consisting of the Earth and the Moon, these orbits are periodic, with two close approaches to the Moon in every orbit period. In this paper, these orbits are revisited. It is found that these orbits belong to the symmetric horseshoe periodic families which bifurcate from the planar Lyapunov family around the collinear libration point L3. Usually, the double lunar swing-by orbits have k= i+ j loops, where i is the number of the inner loops and j is the number of outer loops. The genealogy of these orbits with different i and j is studied in this paper. That is, how these double lunar swing-by orbits are organized in the symmetric horseshoe periodic families is explored. In addition, the 2 n lunar swing-by orbits ( n?2) with 2 n close approaches to the Moon in one orbit period are also studied.

Hou, XiYun; Liu, Lin

2014-04-01

132

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

133

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

134

The Casimir Effect for Parallel Plates Revisited  

E-print Network

The Casimir effect for a massless scalar field with Dirichlet and periodic boundary conditions (b.c.) on infinite parallel plates is revisited in the local quantum field theory (lqft) framework introduced by B.Kay. The model displays a number of more realistic features than the ones he treated. In addition to local observables, as the energy density, we propose to consider intensive variables, such as the energy per unit area $\\epsilon$, as fundamental observables. Adopting this view, lqft rejects Dirichlet (the same result may be proved for Neumann or mixed) b.c., and accepts periodic b.c.: in the former case $\\epsilon$ diverges, in the latter it is finite, as is shown by an expression for the local energy density obtained from lqft through the use of the Poisson summation formula. Another way to see this uses methods from the Euler summation formula: in the proof of regularization independence of the energy per unit area, a regularization-dependent surface term arises upon use of Dirichlet b.c. but not periodic b.c.. For the conformally invariant scalar quantum field, this surface term is absent, due to the condition of zero trace of the energy momentum tensor, as remarked by B.De Witt. The latter property does not hold in tha application to the dark energy problem in Cosmology, in which we argue that periodic b.c. might play a distinguished role.

N. A. Kawakami; M. C. Nemes; W. F. Wreszinski

2006-11-12

135

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

136

Quantization of the Nonlinear Sigma Model Revisited  

E-print Network

We revisit the subject of perturbatively quantizing the nonlinear sigma model in two dimensions from a rigorous, mathematical point of view. Our main contribution is to make precise the cohomological problem of eliminating potential anomalies that may arise when trying to preserve symmetries under quantization. The symmetries we consider are twofold: (i) diffeomorphism covariance for a general nonlinear sigma model; (ii) a transitive group of isometries in the special case when the target space is a homogeneous space. We show that there are no anomalies in case (i) and if in addition H_1(X) = 0 then (ii) is also anomaly-free, in agreement with the work of Friedan. We carry out some explicit computations for the O(N)-model. Finally, we show how a suitable notion of the renormalization group establishes the Ricci flow as the one loop renormalization group flow of the theory. Our approach follows the rigorous formulation of perturbative quantum field theory in the Batalin-Vilkovisky formalism due to K. Costello.

Nguyen, Timothy

2014-01-01

137

The Faraday effect revisited: General theory  

E-print Network

This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. At zero temperature and zero frequency, if the Fermi energy lies in a spectral gap, we rigorously prove the Widom-Streda formula. For free electrons, the transverse conductivity can be explicitly computed and coincides with the classical result. In the general case, using magnetic perturbation theory, the conductivity tensor is expanded in powers of the strength of the magnetic field $B$. Then the linear term in $B$ of this expansion is written down in terms of the zero magnetic field Green function and the zero field current operator. In the periodic case, the linear term in $B$ of the conductivity tensor is expressed in terms of zero magnetic field Bloch functions and energies. No derivatives with respect to the quasi-momentum appear and thereby all ambiguities are removed, in contrast to earlier work.

Horia D. Cornean; G. Nenciu; Thomas G. Pedersen

2005-06-17

138

The Faraday effect revisited: General theory  

NASA Astrophysics Data System (ADS)

This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. At zero temperature and zero frequency, if the Fermi energy lies in a spectral gap, we rigorously prove the Widom-Streda formula. For free electrons, the transverse conductivity can be explicitly computed and coincides with the classical result. In the general case, using magnetic perturbation theory, the conductivity tensor is expanded in powers of the strength of the magnetic field $B$. Then the linear term in $B$ of this expansion is written down in terms of the zero magnetic field Green function and the zero field current operator. In the periodic case, the linear term in $B$ of the conductivity tensor is expressed in terms of zero magnetic field Bloch functions and energies. No derivatives with respect to the quasi-momentum appear and thereby all ambiguities are removed, in contrast to earlier work.

Cornean, Horia D.; Nenciu, Gheorghe; Pedersen, Thomas G.

2006-01-01

139

Revisiting the phase diagram of hard ellipsoids  

NASA Astrophysics Data System (ADS)

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.

Odriozola, Gerardo

2012-04-01

140

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

141

Revisiting the Trust Effect in Urban Elementary Schools  

ERIC Educational Resources Information Center

More than a decade after Goddard, Tschannen-Moran, and Hoy (2001) found that collective faculty trust in clients predicts student achievement in urban elementary schools, we sought to identify a plausible link for this relationship. Our purpose in revisiting the trust effect was twofold: (1) to test the main effect of collective faculty trust on…

Adams, Curt M.; Forsyth, Patrick B.

2013-01-01

142

Disk Scheduling Revisited Margo Seltzer, Peter Chen, John Ousterhout  

E-print Network

Disk Scheduling Revisited Margo Seltzer, Peter Chen, John Ousterhout Computer Science Division scheduling of disk accesses. We have applied these techniques to systems with large memories and potentially utilization by applying some traditional disk scheduling tech- niques. We have analyzed these techniques

Chen, Peter M.

143

Disk Scheduling Revisited+ Margo Seltzer, Peter Chen, John Ousterhout  

E-print Network

Disk Scheduling Revisited+ Margo Seltzer, Peter Chen, John Ousterhout Computer Science Division scheduling of disk accesses. We have applied these techniques to systems with large memories and potentially utilization by applying some traditional disk scheduling tech­ niques. We have analyzed these techniques

144

LUCAS' SQUARE PYRAMID PROBLEM REVISITED MICHAEL A. BENNETT  

E-print Network

LUCAS' SQUARE PYRAMID PROBLEM REVISITED MICHAEL A. BENNETT Abstract. We discuss positive integer'elle en contient vingt-quatre sur le c^ot´e de la base. ´Eduouard Lucas [26] This assertion of Lucas, made solutions by Moret-Blanc [32] and Lucas [27] contain fatal flaws (see e.g. [42] for details

Bennett, Michael A.

145

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

146

The IO and OI hierarchies revisited Gregory M. Kobele1  

E-print Network

The IO and OI hierarchies revisited Gregory M. Kobele1 and Sylvain Salvati2 1 University of Chicago languages of -terms generated by IO and OI un- safe grammars. These languages can be used to model meaning of the decidability results for OI, we identify a de- cidable variant of the -definability problem, and prove

Boyer, Edmond

147

Sony Revisited: A new look at contributory copyright infringement*  

E-print Network

of the copyright, and therefore the right to determine the business model for its distribution to the publicSony Revisited: A new look at contributory copyright infringement* Lee A. Hollaar Professor, School considerable resources in producing the infringing products and had to have a suitable worldwide distribution

Hollaar, Lee A.

148

Environmental Education and Politics: Snakes and Ladders Revisited  

ERIC Educational Resources Information Center

This paper revisits the history of environmental education in Australia in the 1970s and 1980s and draws parallels between these and current events in four countries, including Australia. It is argued that little has changed and that few environmental educators confront the inherently political nature of their work. It is concluded that…

Chapman, David

2004-01-01

149

Language Transmission Revisited: Family Type, Linguistic Environment and Language Attitudes  

ERIC Educational Resources Information Center

This article revisits factors in intergenerational language maintenance and shift within the family. It does so through an in-depth analysis of what 14 migrants to Australia from German-speaking Switzerland reported in written life stories and subsequent life story interviews. The participants represent four family types and a wide age range, and…

Schupbach, Doris

2009-01-01

150

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

151

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

152

Revisiting Bertin Matrices: New Interactions for Crafting Tabular Visualizations  

E-print Network

Revisiting Bertin Matrices: New Interactions for Crafting Tabular Visualizations Charles Perin" by encoding cell values visually and grouping similar rows and columns. Although there were several attempts and accessible to any scientist and researcher [42]. It was based on two simple ideas: i) encoding table

Paris-Sud XI, Université de

153

Re-Visiting Health Informatics What is Health Informatics?  

E-print Network

Re-Visiting Health Informatics HINF1100 Fall 2008 #12;What is Health Informatics? · Health the effective organization, analysis, management and use of health information to improve the delivery and practice of healthcare · Health Informatics is the study of applying information and technology to improve

Abidi, Syed Sibte Raza

154

Calculational reasoning revisited an Isabelle/Isar experience  

E-print Network

Calculational reasoning revisited an Isabelle/Isar experience Gertrud Bauer and Markus Wenzel within Isabelle/Isar, which provides a framework for high-level natural deduction proofs that may commands are added to the basic Isar proof language in a flexible and non-intrusive manner. Thus

Wenzel, Makarius "Markus"

155

Threshold Concepts and Student Engagement: Revisiting Pedagogical Content Knowledge  

ERIC Educational Resources Information Center

This article revisits the notion that to facilitate quality learning requires teachers in higher education to have pedagogical content knowledge. It constructs pedagogical content knowledge as a teaching and learning space that brings content and pedagogy together. On the content knowledge side, it suggests that threshold concepts, akin to a…

Zepke, Nick

2013-01-01

156

Open Mushrooms: Stickiness revisited Carl P. Dettmann 1  

E-print Network

Open Mushrooms: Stickiness revisited Carl P. Dettmann 1 and Orestis Georgiou 1 1 School of Mathematics, University of Bristol, United Kingdom We investigate mushroom billiards, a class of dynamical a generalized mushroom and using properties of continued fractions, we describe a zero measure set of control

Dettmann, Carl

157

Nurse Rostering and Integer Programming Revisited John Thornton  

E-print Network

to effectively manage the computational resources. Schedule quality and staff allocation quality measuresNurse Rostering and Integer Programming Revisited John Thornton School of Information Technology : easjohnt@cit.gu.edu.au Abdul Sattar School of Computing and Information Technology, Faculty of Science

Thornton, John

158

Airfoil Design via Cubic Splines Ferguson's Curves Revisited  

E-print Network

Airfoil Design via Cubic Splines ­ Ferguson's Curves Revisited Andr´as S´obester , Andy J. Keane since the 1960s, and we propose it as a means of airfoil parameterization, it being ideally suited show that in the interest of parameterization parsimony, adequate airfoil shape control can be achieved

Sóbester, András

159

The Internet Hunt Revisited: Personal Information Accessible via the Web  

E-print Network

The Internet Hunt Revisited: Personal Information Accessible via the Web Kay Connelly, Tom Jagatic Gates posted an unusual Internet Hunt[4] to his monthly contest in usenet (alt.internet.services): he will not make contact with the subjects who are the targets of our hunt. · We shall not go to a library or any

Connelly, Kay

160

Revisiting the Art of Collaboration in the Age of Internet  

Microsoft Academic Search

The paper establishes the necessity for collaboration for effective supply chain management in the age of Internet. In a networked society where everything is connected, collaboration is the word visited and revisited every now and then. How can we collaborate to optimize resources efficiently? This paper briefly explores some enablers, obstacles for supply chains and proposes some basic components of

Saadat M. Alhashmi

161

A Multi-Level Model of Moral Functioning Revisited  

ERIC Educational Resources Information Center

The model of moral functioning scaffolded in the 2008 "JME" Special Issue is here revisited in response to three papers criticising that volume. As guest editor of that Special Issue I have formulated the main body of this response, concerning the dynamic systems approach to moral development, the problem of moral relativism and the role of…

Reed, Don Collins

2009-01-01

162

CD2Alloy: Class Diagrams Analysis Using Alloy Revisited  

E-print Network

CD2Alloy: Class Diagrams Analysis Using Alloy Revisited Shahar Maoz , Jan Oliver Ringert present CD2Alloy, a novel, powerful translation of UML class diagrams (CDs) to Alloy. Unlike existingAlloy uses a deeper embedding strategy. Rather than mapping each CD construct to a semantically

Maoz, Shahar

163

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

164

Precision Grip Force Control of Older and Younger Adults, Revisited  

Microsoft Academic Search

This study revisited the hypothesis that older adults lose some ability to efficiently control precision grip force. A previous study demonstrated such a decrement in older adults' performance in a vertical lift and support maneuver. This study employed a similar paradigm in which dynamic forces were applied with a simulated hand tool while measuring grip force and force applied with

Brian D. Lowe

2001-01-01

165

The Importance of Being a Complement: CED Effects Revisited  

ERIC Educational Resources Information Center

This dissertation revisits subject island effects (Ross 1967, Chomsky 1973) cross-linguistically. Controlled acceptability judgment studies in German, English, Japanese and Serbian show that extraction out of specifiers is consistently degraded compared to extraction out of complements, indicating that the Condition on Extraction domains (CED,…

Jurka, Johannes

2010-01-01

166

The anatomy and physiology of the grid revisited  

Microsoft Academic Search

In this paper, we revisit the widely cited domain- specific software architecture (DSSA) for the domain of grid computing We have comprehensively studied 18 grid systems over the past five years, observing that, while individual grid systems are widely used and deemed successful, the grid DSSA is underspecified and makes it difficult to pinpoint what makes a soft- ware system

Chris A. Mattmann; Joshua Garcia; Ivo Krka; Daniel Popescu; Nenad Medvidovic

2009-01-01

167

2-Hydroxy-3-methoxybenzaldehyde (o-vanillin) revisited  

E-print Network

The structure of ortho-vanillin, C[subscript 8]H[subscript 8]O[subscript 3], has been revisited with modern methods and at low temperature (100 K). The previous structure [Iwasaki et al. (1976). Acta Cryst. B32, 1264-1266] ...

Shin, David

168

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

169

WAC Revisited: You Get What You Pay for  

ERIC Educational Resources Information Center

In 1982, the author wrote an essay for the second issue of "The Writing Instructor," "Approaches to Comprehensive Writing: Integrating Writing into the College Curriculum," reviewing the early stages of the modern Writing Across the Curriculum (WAC)/Writing in the Disciplines (WID) movement. In this article, the author revisits his essay and…

Perelman, Les

2011-01-01

170

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

171

Titan interaction with Saturn's magnetosphere: Voyager 1 results revisited  

E-print Network

Titan interaction with Saturn's magnetosphere: Voyager 1 results revisited E. C. Sittler Jr., R. E March 2005; published 10 September 2005. [1] We investigate the details of Titan's interaction in the outermost region with respect to Titan's ``ionopause,'' followed by CH4 + at intermediate distances and N2

Johnson, Robert E.

172

Landscape Planning and Conservation Biology: Systems Thinking Revisited  

E-print Network

systems thinking. These approaches integrated biogeophysical and human factors to analyze and reLandscape Planning and Conservation Biology: Systems Thinking Revisited JOAN IVERSON NASSAUER planning in the era of the first Earth Day, one sees strong evidence of systems thinking in both fields. So

Nassauer, Joan Iverson

173

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

174

High Precision Mass Measurements in $\\psi$ and $\\Upsilon$ Families Revisited  

E-print Network

High precision mass measurements in $\\Psi$ and $\\Upsilon$ families performed in 1980-1984 at the VEPP-4 collider with OLYA and MD-1 detectors are revisited. The corrections for the new value of the electron mass are presented. The effect of the updated radiative corrections has been calculated for the $J/\\Psi(1S)$ and $\\Psi(2S)$ mass measurements.

Artamonov, S A; Blinov, A E; Blinov, V E; Bondar, A E; Bukin, A D; Chilingarov, A G; Denisov, N F; Eidelman, S I; Eidelman, Yu I; Groshev, V R; Inozemtsev, N I; Kezerashvili, G Ya; Kiselev, V A; Klimenko, S G; Kolachev, G M; Kuper, E A; Kurdadze, L M; Lelchuk, M Yu; Mishnev, S I; Nikitin, S A; Onuchin, A P; Pakhtusova, E V; Panin, V S; Petrov, V V; Protopopov, I Ya; Saldin, E L; Shamov, A G; Shatunov, Yu M; Shwartz, B A; Sidorov, V A; Skovpen, Yu I; Skrinsky, A N; Tayursky, V A; Telnov, V I; Temnykh, A B; Tikhonov, Yu A; Tumaikin, G M; Undrus, A E; Vorobiev, A I; Yurkov, M V; Zhilich, V N; Zholents, A A

2000-01-01

175

A Truly Early Starter Model of Antisocial Behavior Revisited  

Microsoft Academic Search

This paper revisits a developmental model of the origins of early conduct problems. Several of the model's primary tenets have now been validated in two samples of at-risk children followed prospectively from infancy to school-age. In both cohorts, child, family, and sociodemographic factors all play a significant role in the development of early conduct problems. In particular, the quality of

Daniel S. Shaw; Richard Q. Bell; Miles Gilliom

2000-01-01

176

The lifting of polynomial traces revisited Christine Bernardi1  

E-print Network

The lifting of polynomial traces revisited Christine Bernardi1 , Monique Dauge2 , and Yvon Maday1 Abstract We construct a lifting operator of polynomial traces on an interval that is stable in appropriate whole boundary or parts of it. They are also the natural measures for deriving stable liftings

Paris-Sud XI, Université de

177

Revisiting the structural validity of the Gender Role Conflict Scale  

Microsoft Academic Search

Despite masculinity researchers' widespread use of the Gender Role Conflict Scale (GRCS; J. M. O'Neil, B. Helms, R. Gable, L. David, & L.Wrightsman, 1986), the structural validity of this instrument has recently been called into question. The authors revisited the status of the GRCS's structural validity via confirmatory factor analyses of both rationally and randomly developed item parcels as well

Bonnie Moradi; David M. Tokar; Michael Schaub; LaRae M. Jome; George S. Serna

2000-01-01

178

HARE++: Hardware Assisted Reverse Execution Revisited Ioannis Doudalis  

E-print Network

HARE++: Hardware Assisted Reverse Execution Revisited Ioannis Doudalis Georgia Institute- nique. HARE++ reduces the reverse execution latency by 3.5-4 times on average compared to HARE-accelerators. 1. Introduction Debugging is a time consuming, yet important, process during soft- ware development

Prvulovic, Milos

179

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

180

Reply: Central American forearc slip revisited Charles DeMets  

E-print Network

Reply: Central American forearc slip revisited Charles DeMets Department of Geology and Geophysics; published XX Month 2002. [1] I thank Guzman-Speziale and Gomez (GSG02) for their comments on DeMets (2001 in this region [White, 1991; DeMets, 2001]. Below, I address their reservations. INDEX TERMS: 8107 Tectonophysics

DeMets, Chuck

181

Multiple-use forestry vs. forestland-use specialization revisited  

Microsoft Academic Search

Based on the comparative advantages of forestland in providing a variety of products and services, it is not arguable that different kinds of forestland should produce different compositions of outputs. To investigate the issue regarding forestland-use specialization or the pursuit of multiple uses on same piece of land, this paper starts by revisiting Vincent and Binkley's paper ‘Efficient Multiple-Use Forestry

Yaoqi Zhang

2005-01-01

182

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

183

Finite size mass shift formula for stable particles revisited  

E-print Network

Luescher's finite size mass shift formula in a periodic finite volume, involving forward scattering amplitudes in the infinite volume, is revisited for the two stable distinguishable particle system. The generalized mass shift formulae for the boson and fermion are derived in the boson-boson and fermion-boson systems, respectively. The nucleon mass shift is discussed in the nucleon-pion system.

Koma, Y; Koma, Yoshiaki; Koma, Miho

2004-01-01

184

Antidote for Zero Tolerance: Revisiting a "Reclaiming" School.  

ERIC Educational Resources Information Center

Reports on a revisit to the Frank Lloyd Wright Middle School, which implemented strategies to deal with disciplinary problems. The school continues to progress towards creating the type of reclaiming environment necessary to ensure the needs of all students. Strategies used include alternatives to zero tolerance policy; smaller teams of students;…

Farner, Conrad D.

2002-01-01

185

`Similarity breeds liking' revisited: The moderating role of  

E-print Network

`Similarity breeds liking' revisited: The moderating role of commitment David M. Amodio New York of a Master's thesis submitted to the University of Wisconsin ­ Madison by David Amodio. All correspondence a variety of dimensions, including attitudes (Byrne, 1971), personal- ity traits (Buss, 1984; Terman

186

White Matter Integrity is Reduced in Bulimia Nervosa  

PubMed Central

Objective To investigate brain white matter (WM) functionality in bulimia nervosa (BN) in relation to anxiety. Method Twenty-one control (CW, mean age 27±7 years) and 20 BN women (mean age 25±5 years) underwent brain diffusion tensor imaging (DTI) to measure fractional anisotropy (FA; an indication of WM axon integrity) and the apparent diffusion coefficient (ADC; reflecting WM cell damage). Results FA was decreased in BN in the bilateral corona radiata extending into the posterior limb of the internal capsule, the corpus callosum, the right sub-insular white matter and right fornix. In CW but not BN trait anxiety correlated negatively with fornix, corpus callosum and left corona radiata FA. ADC was increased in BN compared to CW in the bilateral corona radiata, corpus callosum, inferior fronto-occipital and uncinate fasciculus. Alterations in BN WM functionality were not due to structural brain alterations. Discussion WM integrity is disturbed in BN, especially in the corona radiate, which has been associated with taste and brain reward processing. Whether this is a premorbid condition or an effect from the illness is yet uncertain. The relationships between WM FA and trait anxiety in CW but not BN may suggest that altered WM functionality contributes to high anxious traits in BN. PMID:23354827

Mettler, Lisa N.; Shott, Megan E.; Pryor, Tamara; Yang, Tony T.; Frank, Guido K.W.

2013-01-01

187

Diffusion tensor tractography in hypothyroidism and its correlation with memory function.  

PubMed

Diffusion tensor tractography (DTT) was performed to determine the microstructural changes in the white matter fibre tracts of hypothyroid patients compared to controls and to correlate these changes with memory dysfunction scores. DTT and Postgraduate Institute Memory Scale test were performed in eight hypothyroid patients and eight healthy controls. Diffusion tensor imaging (DTI) measures [fractional anisotropy (FA) and mean diffusivity (MD)] from all of the major cerebral tracts were calculated and a comparison was made between the patient group and controls. Pearson's correlation was performed between Memory Dysfunction score and DTI measures. Significant changes in DTI measures were observed in various white matter fibre tracts in hypothyroid patients compared to controls. In hypothyroid patients, an inverse correlation of Memory Dysfunction score with FA was observed in the right and left inferior fronto-occipital fasciculus, whereas a positive correlation with MD was observed in the right anterior thalamic radiation among all white matter tracts. These findings suggest that microstructural changes in white matter fibres may contribute to the underlying dysfunction in memory in hypothyroid patients. PMID:25131823

Singh, S; Trivedi, R; Singh, K; Kumar, P; Shankar, L R; Khushu, S

2014-11-01

188

Altered fimbria-fornix white matter integrity in anorexia nervosa predicts harm avoidance  

PubMed Central

The eating disorder anorexia nervosa (AN) is associated with high anxiety. The brain mechanisms that drive those behaviors are unknown. In this study we wanted to test whether brain WM integrity is altered in AN, and related to heightened anxiety. Sixteen adult women with AN (mean age 24±7 years) and 17 healthy control women (CW, mean age 25±4 years) underwent diffusion tensor imaging (DTI) of the brain. The DTI brain images were used to calculate the fractional anisotropy (FA) of WM tracts, which is a measure for WM integrity. AN individuals compared to CW showed clusters of significantly reduced FA (p<0.05, corrected) in the bilateral fimbria-fornix, fronto-occipital fasciculus, as well as posterior cingulum WM. In the AN group, Harm Avoidance was predicted by left (F=5.8, Beta=?0.54, p<0.03) and right (F=6.0, Beta=?0.55, p<0.03) fimbria-fornix FA. Those findings were not due to WM volume deficits in AN. This study indicates that WM integrity is abnormal in AN in limbic and association pathways, which could contribute to disturbed feeding, emotion processing and body perception in AN. The prediction of Harm Avoidance in AN by fimbria-fornix WM integrity suggests that this pathway may be mechanistically involved in high anxiety in AN. PMID:21498054

Kazlouski, Demitry; Rollin, Michael D.H.; Tregellas, Jason; Shott, Megan E.; Jappe, Leah M.; Hagman, Jennifer O.; Pryor, Tamara; Yang, Tony T.; Frank, Guido K.W.

2011-01-01

189

Sex-linked white matter microstructure of the social and analytic brain.  

PubMed

Sexual dimorphism in the brain is known to underpin sex differences in neuropsychological behaviors. The white matter (WM) microstructure appears to be coupled with cognitive performances. However, the issues concerning sex differences in WM remains to be determined. This study used the tract-based spatial statistics on diffusion tensor imaging concurrently with the assessments of Empathizing Quotient (EQ) and Systemizing Quotient (SQ) in forty healthy female and forty male adults. Females exhibited greater fractional anisotropy (FA) in the fronto-occipital fasciculus, body of the corpus callosum, and WM underlying the parahippocampal gyrus. Males exhibited larger FA in the bilateral internal capsule, WM underlying the medial frontal gyrus, fusiform gyrus, hippocampus, insula, postcentral gyrus, frontal and temporal lobe. Interestingly, the interaction analysis of dispositional measures by sex showed that females had a positive correlation between FA of the WM underlying the inferior parietal lobule and superior temporal gyrus and EQ but a negative correlation between FA of the occipital and postcentral gyrus and SQ. Males displayed the opposite effect. The findings indicate a sexual dimorphism of WM microstructure. Divergent correlations of WM microstructure and neuropsychological behaviors between sexes may account for the higher prevalence of autism spectrum disorders in males. PMID:20633662

Chou, Kun-Hsien; Cheng, Yawei; Chen, I-Yun; Lin, Ching-Po; Chu, Woei-Chyn

2011-01-01

190

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

191

Autosomal recessive cutis laxa syndrome revisited  

PubMed Central

The clinical spectrum of the autosomal recessive cutis laxa syndromes is highly heterogeneous with respect to organ involvement and severity. One of the major diagnostic criteria is to detect abnormal elastin fibers. In several other clinically similar autosomal recessive syndromes, however, the classic histological anomalies are absent, and the definite diagnosis remains uncertain. In cutis laxa patients mutations have been demonstrated in elastin or fibulin genes, but in the majority of patients the underlying genetic etiology remains unknown. Recently, we found mutations in the ATP6V0A2 gene in families with autosomal recessive cutis laxa. This genetic defect is associated with abnormal glycosylation leading to a distinct combined disorder of the biosynthesis of N- and O-linked glycans. Interestingly, similar mutations have been found in patients with wrinkly skin syndrome, without the presence of severe skin symptoms of elastin deficiency. These findings suggest that the cutis laxa and wrinkly skin syndromes are phenotypic variants of the same disorder. Interestingly many phenotypically similar patients carry no mutations in the ATP6V0A2 gene. The variable presence of protein glycosylation abnormalities in the diverse clinical forms of the wrinkled skin-cutis laxa syndrome spectrum necessitates revisiting the diagnostic criteria to be able to offer adequate prognosis assessment and counseling. This paper aims at describing the spectrum of clinical features of the various forms of autosomal recessive cutis laxa syndromes. Based on the recently unraveled novel genetic entity we also review the genetic aspects in cutis laxa syndromes including genotype–phenotype correlations and suggest a practical diagnostic approach. PMID:19401719

Morava, Eva; Guillard, Mailys; Lefeber, Dirk J; Wevers, Ron A

2009-01-01

192

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

193

Revisiting mu suppression in autism spectrum disorder.  

PubMed

Two aspects of the EEG literature lead us to revisit mu suppression in Autism Spectrum Disorder (ASD). First and despite the fact that the mu rhythm can be functionally segregated in two discrete sub-bands, 8-10Hz and 10-12/13Hz, mu-suppression in ASD has been analyzed as a homogeneous phenomenon covering the 8-13Hz frequency. Second and although alpha-like activity is usually found across the entire scalp, ASD studies of action observation have focused on the central electrodes (C3/C4). The present study was aimed at testing on the whole brain the hypothesis of a functional dissociation of mu and alpha responses to the observation of human actions in ASD according to bandwidths. Electroencephalographic (EEG) mu and alpha responses to execution and observation of hand gestures were recorded on the whole scalp in high functioning subjects with ASD and typical subjects. When two bandwidths of the alpha-mu 8-13Hz were distinguished, a different mu response to observation appeared for subjects with ASD in the upper sub-band over the sensorimotor cortex, whilst the lower sub-band responded similarly in the two groups. Source reconstructions demonstrated that this effect was related to a joint mu-suppression deficit over the occipito-parietal regions and an increase over the frontal regions. These findings suggest peculiarities in top-down response modulation in ASD and question the claim of a global dysfunction of the MNS in autism. This research also advocates for the use of finer grained analyses at both spatial and spectral levels for future directions in neurophysiological accounts of autism. PMID:25148709

Dumas, Guillaume; Soussignan, Robert; Hugueville, Laurent; Martinerie, Jacques; Nadel, Jacqueline

2014-10-17

194

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 Letters 93, 3 (2006) pp. 354-359" #12;2 Urban income inequality in China revisited (1988-2002)* 1 of these biases for urban household disposable income inequality over the 1988-2002 period, by using new data

Boyer, Edmond

195

Revisiting the parameterization of potential evaporation as a driver of long-term water balance trends  

E-print Network

Revisiting the parameterization of potential evaporation as a driver of long-term water balance), Revisiting the parameterization of potential evaporation as a driver of long-term water balance trends, herein denoted potential evaporation (Ep), and the available water. 1.2. Water- and Energy

Dai, Aiguo

196

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

197

Longitudinal changes of structural connectivity in traumatic axonal injury  

PubMed Central

Objectives: To identify structural connectivity change occurring during the first 6 months after traumatic brain injury and to evaluate the utility of diffusion tensor tractography for predicting long-term outcome. Methods: The participants were 28 patients with mild to severe traumatic axonal injury and 20 age- and sex-matched healthy control subjects. Neuroimaging was obtained 0–9 days postinjury for acute scans and 6–14 months postinjury for chronic scans. Long-term outcome was evaluated on the day of the chronic scan. Twenty-eight fiber regions of 9 major white matter structures were reconstructed, and reliable tractography measurements were determined and used. Results: Although most (23 of 28) patients had severe brain injury, their long-term outcome ranged from good recovery (16 patients) to moderately (5 patients) and severely disabled (7 patients). In concordance with the diverse outcome, the white matter change in patients was heterogeneous, ranging from improved structural connectivity, through no change, to deteriorated connectivity. At the group level, all 9 fiber tracts deteriorated significantly with 7 (corpus callosum, cingulum, angular bundle, cerebral peduncular fibers, uncinate fasciculus, and inferior longitudinal and fronto-occipital fasciculi) showing structural damage acutely and 2 (fornix body and left arcuate fasciculus) chronically. Importantly, the amount of change in tractography measurements correlated with patients' long-term outcome. Acute tractography measurements were able to predict patients' learning and memory performance; chronic measurements also determined performance on processing speed and executive function. Conclusions: Diffusion tensor tractography is a valuable tool for identifying structural connectivity changes occurring between the acute and chronic stages of traumatic brain injury and for predicting patients' long-term outcome. PMID:21813787

Wang, J.Y.; Bakhadirov, K.; Abdi, H.; Devous, M.D.; Marquez de la Plata, C.D.; Moore, C.; Madden, C.J.

2011-01-01

198

A longitudinal diffusion tensor imaging study assessing white matter fiber tracts after sports-related concussion.  

PubMed

Abstract The extent of structural injury in sports-related concussion (SRC) is central to the course of recovery, long-term effects, and the decision to return to play. In the present longitudinal study, we used diffusion tensor imaging (DTI) to assess white matter (WM) fiber tract integrity within 2 days, 2 weeks, and 2 months of concussive injury. Participants were right-handed male varsity contact-sport athletes (20.2±1.0 years of age) with a medically diagnosed SRC (no loss of consciousness). They were compared to right-handed male varsity non-contact-sport athletes serving as controls (19.9±1.7 years). We found significantly increased radial diffusivity (RD) in concussed athletes (n=12; paired t-test, tract-based spatial statistics; p<0.025) at 2 days, when compared to the 2-week postinjury time point. The increase was found in a cluster of right hemisphere voxels, spanning the posterior limb of the internal capsule (IC), the retrolenticular part of the IC, the inferior longitudinal fasciculus, the inferior fronto-occipital fasciculus (sagittal stratum), and the anterior thalamic radiation. Post-hoc, univariate, between-group (controls vs. concussed), mixed-effects analysis of the cluster showed significantly higher RD at 2 days (p=0.002), as compared to the controls, with a trend in the same direction at 2 months (p=0.11). Results for fractional anisotropy (FA) in the same cluster showed a similar, but inverted, pattern; FA was decreased at 2 days and at 2 months postinjury, when compared to healthy controls. At 2 weeks postinjury, no statistical differences between concussed and control athletes were found with regard to either RD or FA. These results support the hypothesis of increased RD and reduced FA within 72?h postinjury, followed by recovery that may extend beyond 2 weeks. RD appears to be a sensitive measure of concussive injury. PMID:24786666

Murugavel, Murali; Cubon, Valerie; Putukian, Margot; Echemendia, Ruben; Cabrera, Javier; Osherson, Daniel; Dettwiler, Annegret

2014-11-15

199

Relationship of a variant in the NTRK1 gene to white matter microstructure in young adults.  

PubMed

The NTRK1 gene (also known as TRKA) encodes a high-affinity receptor for NGF, a neurotrophin involved in nervous system development and myelination. NTRK1 has been implicated in neurological function via links between the T allele at rs6336 (NTRK1-T) and schizophrenia risk. A variant in the neurotrophin gene, BDNF, was previously associated with white matter integrity in young adults, highlighting the importance of neurotrophins to white matter development. We hypothesized that NTRK1-T would relate to lower fractional anisotropy in healthy adults. We scanned 391 healthy adult human twins and their siblings (mean age: 23.6 ± 2.2 years; 31 NTRK1-T carriers, 360 non-carriers) using 105-gradient diffusion tensor imaging at 4 tesla. We evaluated in brain white matter how NTRK1-T and NTRK1 rs4661063 allele A (rs4661063-A, which is in moderate linkage disequilibrium with rs6336) related to voxelwise fractional anisotropy-a common diffusion tensor imaging measure of white matter microstructure. We used mixed-model regression to control for family relatedness, age, and sex. The sample was split in half to test reproducibility of results. The false discovery rate method corrected for voxelwise multiple comparisons. NTRK1-T and rs4661063-A correlated with lower white matter fractional anisotropy, independent of age and sex (multiple-comparisons corrected: false discovery rate critical p = 0.038 for NTRK1-T and 0.013 for rs4661063-A). In each half-sample, the NTRK1-T effect was replicated in the cingulum, corpus callosum, superior and inferior longitudinal fasciculi, inferior fronto-occipital fasciculus, superior corona radiata, and uncinate fasciculus. Our results suggest that NTRK1-T is important for developing white matter microstructure. PMID:22539856

Braskie, Meredith N; Jahanshad, Neda; Stein, Jason L; Barysheva, Marina; Johnson, Kori; McMahon, Katie L; de Zubicaray, Greig I; Martin, Nicholas G; Wright, Margaret J; Ringman, John M; Toga, Arthur W; Thompson, Paul M

2012-04-25

200

Faraday effect revisited: sum rules and convergence issues  

NASA Astrophysics Data System (ADS)

This is the third paper of a series revisiting the Faraday effect. The question of the absolute convergence of the sums over the band indices entering the Verdet constant is considered. In general, sum rules and traces per unit volume play an important role in solid-state physics, and they give rise to certain convergence problems widely ignored by physicists. We give a complete answer in the case of smooth potentials and formulate a number of open problems related to less regular perturbations.

Cornean, Horia D.; Nenciu, Gheorghe

2010-11-01

201

Fall Semester: A Time for Parents to Revisit Discussions about College Drinking  

MedlinePLUS

... A Time for Parents to Revisit Discussions about College Drinking As college students arrive on campus this fall, it is ... even death. According to research summarized in a College Task Force report to the National Institute on ...

202

The Friedberg Jump Inversion Theorem Revisited: A Study of Undefinable Cuts  

E-print Network

1 #12; The Friedberg Jump Inversion Theorem Revisited: A Study of Undefinable Cuts C. T. Chong, Lei Mathematics Subject Classification. 03D20, 03F30, 03H15 #12; large class of degrees. In the model studied

Yang, Yue

203

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

204

Dioecy and Gametophytic Self-Incompatibility: Reproductive Efficiency Revisited Author(s): Keith Karoly  

E-print Network

Dioecy and Gametophytic Self-Incompatibility: Reproductive Efficiency Revisited Author(s): KeithAmericanNaturalist October1994 NOTES AND COMMENTS DIOECY AND GAMETOPHYTIC SELF-INCOMPATIBILITY: REPRODUCTIVE EFFICIENCY

Thomson, James D.

205

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 if known results in Computer-Go and various other games are general enough for being applied directly

Paris-Sud XI, Université de

206

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

2014-05-09

207

Reading Impairment in a Patient with Missing Arcuate Fasciculus  

ERIC Educational Resources Information Center

We describe the case of a child ("S") who was treated with radiation therapy at age 5 for a recurrent malignant brain tumor. Radiation successfully abolished the tumor but caused radiation-induced tissue necrosis, primarily affecting cerebral white matter. "S" was introduced to us at age 15 because of her profound dyslexia. We assessed cognitive…

Rauschecker, Andreas M.; Deutsch, Gayle K.; Ben-Shachar, Michal; Schwartzman, Armin; Perry, Lee M.; Dougherty, Robert F.

2009-01-01

208

Leaning-Based Travel Interfaces Revisited: Frontal versus Sidewise Stances for Flying in 3D Virtual Spaces  

E-print Network

revisit the design of leaning-based travel interfaces and propose a design space to categorize existing-centered design. Keywords Leaning-based travel interface; Stance; Navigation; 3D virtual spaces. 1. INTRODUCTIONLeaning-Based Travel Interfaces Revisited: Frontal versus Sidewise Stances for Flying in 3D Virtual

Lindeman, Robert W.

209

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

210

Star/Galaxy Separation Revisited : Into the Zone of Avoidance  

E-print Network

The problem of automated separation of stars and galaxies on photographic plates is revisited with two goals in mind : First, to separate galaxies from everything else (as opposed to most previous work, in which galaxies were lumped together with all other non-stellar images). And second, to search optically for galaxies at low Galactic latitudes (an area that has been largely avoided in the past). This paper demonstrates how an artificial neural network can be trained to achieve both goals on Schmidt plates of the Digitised Sky Survey. Here I present the method while its application to large numbers of plates is deferred to a later paper. Analysis is also provided of the way in which the network operates and the results are used to counter claims that it is a complicated and incomprehensible tool.

A. Naim

1997-01-29

211

Shuttle entry guidance revisited using nonlinear geometric methods  

NASA Astrophysics Data System (ADS)

The entry guidance law for the space shuttle orbiter is revisited using nonlinear geometric methods. The shuttle guidance concept is to track a reference drag trajectory that has been designed to lead a specified range and velocity. It is shown that the approach taken in the original derivation of the shuttle entry guidance has much in common with the more recently developed feedback linearization method of differential geometric control. Using the feedback linearization method, however, an alternative, potentially superior, guidance law was formulated. Comparing the two guidance laws based performance domains in state space, taking into account the nonlinear dynamics, the alternative guidance law achieves the desired performance over larger domains in state space; the stability domain of the laws are similar. With larger operating domain for the shuttle or some other entry vehicle, the alternative guidance law should be considered.

Mease, Kenneth D.; Kremer, Jean-Paul

1994-11-01

212

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

213

Atlas-based white matter analysis in individuals with velo-cardio-facial syndrome (22q11.2 deletion syndrome) and unaffected siblings  

PubMed Central

Background Velo-cardio-facial syndrome (VCFS, MIM#192430, 22q11.2 Deletion Syndrome) is a genetic disorder caused by a deletion of about 40 genes at the q11.2 band of one copy of chromosome 22. Individuals with VCFS present with deficits in cognition and social functioning, high risk of psychiatric disorders, volumetric reductions in gray and white matter (WM) and some alterations of the WM microstructure. The goal of the current study was to characterize the WM microstructural differences in individuals with VCFS and unaffected siblings, and the correlation of WM microstructure with neuropsychological performance. We hypothesized that individuals with VCFS would have decreased indices of WM microstructure (fractional anisotropy (FA), axial diffusivity (AD) and radial diffusivity (RD)), particularly in WM tracts to the frontal lobe, and that these measures would be correlated with cognitive functioning. Methods Thirty-three individuals with VCFS (21 female) and 16 unaffected siblings (8 female) participated in DTI scanning and neuropsychological testing. We performed an atlas-based analysis, extracted FA, AD, and RD measures for 54 WM tracts (27 in each hemisphere) for each participant, and used MANOVAs to compare individuals with VCFS to siblings. For WM tracts that were statistically significantly different between VCFS and siblings (pFDR?fasciculus, and decreased AD in multiple WM tracts (bilateral superior and posterior corona radiata, dorsal cingulum, inferior fronto-occipital fasciculus, superior longitudinal fasciculus, superior cerebellar peduncle, posterior thalamic radiation, and left anterior corona radiata, retrolenticular part of the internal capsule, external capsule, sagittal stratum). We also found significant correlations of AD with measures of executive function, IQ, working memory, and/or social cognition. Conclusions Our results suggest that individuals with VCFS display abnormal WM connectivity in a widespread cerebro-anatomical network, involving tracts from/to all cerebral lobes and the cerebellum. Future studies could focus on the WM developmental trajectory in VCFS, the association of WM alterations with psychiatric disorders, and the effects of candidate 22q11.2 genes on WM anomalies. PMID:22853778

2012-01-01

214

Interfaces endowed with non-constant surface energies revisited with the d'Alembert-Lagrange principle  

E-print Network

The equation of motions and the conditions on surfaces and edges between fluids and solids in presence of non-constant surface energies, as in the case of surfactants attached to the fluid particles at the interfaces, are revisited under the principle of virtual work. We point out that adequate behaviors of surface concentrations may drastically modify the surface tension which naturally appears in the Laplace and the Young-Dupr\\'e equations. Thus, the principle of virtual work points out a strong difference between the two revisited concepts of surface energy and surface tension.

Henri Gouin

2013-11-05

215

Genetics of brain fiber architecture and intellectual performance.  

PubMed

The study is the first to analyze genetic and environmental factors that affect brain fiber architecture and its genetic linkage with cognitive function. We assessed white matter integrity voxelwise using diffusion tensor imaging at high magnetic field (4 Tesla), in 92 identical and fraternal twins. White matter integrity, quantified using fractional anisotropy (FA), was used to fit structural equation models (SEM) at each point in the brain, generating three-dimensional maps of heritability. We visualized the anatomical profile of correlations between white matter integrity and full-scale, verbal, and performance intelligence quotients (FIQ, VIQ, and PIQ). White matter integrity (FA) was under strong genetic control and was highly heritable in bilateral frontal (a(2)=0.55, p=0.04, left; a(2)=0.74, p=0.006, right), bilateral parietal (a(2)=0.85, p<0.001, left; a(2)=0.84, p<0.001, right), and left occipital (a(2)=0.76, p=0.003) lobes, and was correlated with FIQ and PIQ in the cingulum, optic radiations, superior fronto-occipital fasciculus, internal capsule, callosal isthmus, and the corona radiata (p=0.04 for FIQ and p=0.01 for PIQ, corrected for multiple comparisons). In a cross-trait mapping approach, common genetic factors mediated the correlation between IQ and white matter integrity, suggesting a common physiological mechanism for both, and common genetic determination. These genetic brain maps reveal heritable aspects of white matter integrity and should expedite the discovery of single-nucleotide polymorphisms affecting fiber connectivity and cognition. PMID:19228974

Chiang, Ming-Chang; Barysheva, Marina; Shattuck, David W; Lee, Agatha D; Madsen, Sarah K; Avedissian, Christina; Klunder, Andrea D; Toga, Arthur W; McMahon, Katie L; de Zubicaray, Greig I; Wright, Margaret J; Srivastava, Anuj; Balov, Nikolay; Thompson, Paul M

2009-02-18

216

Fiber tract-specific white matter lesion severity Findings in late-life depression and by AGTR1 A1166C genotype.  

PubMed

Past work demonstrated that late-life depression is associated with greater severity of ischemic cerebral hyperintense white matter lesions, particularly frontal lesions. However, these lesions are also associated with other neuropsychiatric deficits, so these clinical relationships may depend on which fiber tracts are damaged. We examined the ratio of lesion to nonlesioned white matter tissue within multiple fiber tracts between depressed and nondepressed elders. We also sought to determine if the AGTR1 A1166C and BDNF Val66Met polymorphisms contributed to vulnerability to lesion development in discrete tracts. The 3T structural MR images and blood samples for genetic analyses were acquired on 54 depressed and 37 nondepressed elders. Lesion maps were created through an automated tissue segmentation process and applied to a probabilistic white matter fiber tract atlas allowing for identification of the fraction of the tract occupied by lesion. The depressed cohort exhibited a significantly greater lesion ratio only in the left upper cingulum near the cingulate gyrus (F((1,86)) = 4.62, P = 0.0344), supporting past work implicating cingulate dysfunction in the pathogenesis of depression. In the 62 Caucasian subjects with genetic data, AGTR1 C1166 carriers exhibited greater lesion ratios across multiple tracts including the anterior thalamic radiation and inferior fronto-occipital fasciculus. In contrast, BDNF Met allele carriers exhibited greater lesion ratios only in the frontal corpus callosum. Although these findings did not survive correction for multiple comparisons, this study supports our hypothesis and provides preliminary evidence that genetic differences related to vascular disease may increase lesion vulnerability differentially across fiber tracts. PMID:22021115

Taylor, Warren D; Zhao, Zheen; Ashley-Koch, Allison; Payne, Martha E; Steffens, David C; Krishnan, Ranga R; Hauser, Elizabeth; MacFall, James R

2013-02-01

217

The multimodal connectivity of the hippocampal complex in auditory and visual hallucinations.  

PubMed

Hallucinations constitute one of the most representative and disabling symptoms of schizophrenia. Several Magnetic Resonance Imaging (MRI) findings support the hypothesis that distinct patterns of connectivity, particularly within networks involving the hippocampal complex (HC), could be associated with different hallucinatory modalities. The aim of this study was to investigate HC connectivity as a function of the hallucinatory modality, that is, auditory or visual. Two carefully selected subgroups of schizophrenia patients with only auditory hallucinations (AH) or with audio-visual hallucinations (A+VH) were compared using the following three complementary multimodal MRI methods: resting state functional MRI, diffusion MRI and structural MRI were used to analyze seed-based Functional Connectivity (sb-FC), Tract-Based Spatial Statistics (TBSS) and shape analysis, respectively. Sb-FC was significantly higher between the HC, the medial prefrontal cortex (mPFC) and the caudate nuclei in A+VH patients compared with the AH group. Conversely, AH patients exhibited a higher sb-FC between the HC and the thalamus in comparison with the A+VH group. In the A+VH group, TBSS showed specific higher white matter connectivity in the pathways connecting the HC with visual areas, such as the forceps major and the inferior-fronto-occipital fasciculus than in the AH group. Finally, shape analysis showed localized hippocampal hypertrophy in the A+VH group. Functional results support the fronto-limbic dysconnectivity hypothesis of schizophrenia, while specific structural findings indicate that plastic changes are associated with hallucinations. Together, these results suggest that there are distinct connectivity patterns in patients with schizophrenia that depend on the sensory-modality, with specific involvement of the HC in visual hallucinations. PMID:23318999

Amad, A; Cachia, A; Gorwood, P; Pins, D; Delmaire, C; Rolland, B; Mondino, M; Thomas, P; Jardri, R

2014-02-01

218

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

2012-08-20

219

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

220

Biogas from Macroalgae: is it time to revisit the idea?  

PubMed Central

The economic and environmental viability of dedicated terrestrial energy crops is in doubt. The production of large scale biomass (macroalgae) for biofuels in the marine environment was first tested in the late 1960’s. The culture attempts failed due to the engineering challenges of farming offshore. However the energy conversion via anaerobic digestion was successful as the biochemical composition of macroalgae makes it an ideal feedstock. The technology for the mass production of macroalgae has developed principally in China and Asia over the last 50 years to such a degree that it is now the single largest product of aquaculture. There has also been significant technology transfer and macroalgal cultivation is now well tried and tested in Europe and America. The inherent advantage of production of biofuel feedstock in the marine environment is that it does not compete with food production for land or fresh water. Here we revisit the idea of the large scale cultivation of macroalgae at sea for subsequent anaerobic digestion to produce biogas as a source of renewable energy, using a European case study as an example. PMID:23186536

2012-01-01

221

Revisiting the sadomasochistic marriage: the paranoid-masochistic relationship.  

PubMed

The sadomasochistic marriage is thought to be very resistant to change because of the object relations of each member of a couple as well as the sadomasochistic dynamics within the couple. However, the picture may be even more complex because there are times when a psychoanalytic therapist may mistakenly believe he or she is treating a sadomasochistic couple when the couple actually is functioning in a paranoid-masochistic relationship. The present paper reexamines the sadomasochistic marriage by revisiting the work of Nydes, who formulated the concept of paranoid-masochism in individuals and contrasted it to the more commonly understood sadomasochist dynamic. This paper applies his concepts to couples: Just as we understand some couples to be sadomasochistic, other couples may have paranoid-masochistic dynamics, which may require a somewhat different kind of understanding and technical approach than the dynamics of a sadomasochistic couple at the same level of object relations. This may be the reason why some marriages, misdiagnosed as sadomasochistic, are even more difficult to treat than others, because they might be more accurately treated as paranoid-masochistic. PMID:25247285

Mendelsohn, Robert

2014-10-01

222

Leber's Hereditary Optic Neuropathy: The Mitochondrial Connection Revisited  

PubMed Central

Our current understanding of Leber’s hereditary optic neuropathy (LHON)-mitochondrial connection falls short of comprehensive. Twenty years of intensive investigation have yielded a wealth of information about mitochondria, the mitochondrial genome, the metabolism of the optic nerve and other structures, and the phenotypic variability of classic LHON. However, we still cannot completely explain how primary LHON mutations injure the optic nerve or why the optic nerve is particularly at risk. We cannot explain the incomplete penetrance or the male predominance of LHON, the typical onset in young adult life without warning, or the synchronicity of visual loss. Moreover, primary LHON mutations clearly are not present in every family with the LHON phenotype (including multigenerational maternal inheritance), and they are present in only a minority of individuals who have the LHON optic neuropathy phenotype without a family history. All lines of evidence point to abnormalities of the mitochondria as the direct or indirect cause of LHON. Therefore, the mitochondria-LHON connection needs to be revisited and examined closely. This review will attempt to do that and provide an update on various aspects of LHON. PMID:21572729

Abu-Amero, Khaled K.

2011-01-01

223

Leber's Hereditary Optic Neuropathy: The Mitochondrial Connection Revisited.  

PubMed

Our current understanding of Leber's hereditary optic neuropathy (LHON)-mitochondrial connection falls short of comprehensive. Twenty years of intensive investigation have yielded a wealth of information about mitochondria, the mitochondrial genome, the metabolism of the optic nerve and other structures, and the phenotypic variability of classic LHON. However, we still cannot completely explain how primary LHON mutations injure the optic nerve or why the optic nerve is particularly at risk. We cannot explain the incomplete penetrance or the male predominance of LHON, the typical onset in young adult life without warning, or the synchronicity of visual loss. Moreover, primary LHON mutations clearly are not present in every family with the LHON phenotype (including multigenerational maternal inheritance), and they are present in only a minority of individuals who have the LHON optic neuropathy phenotype without a family history. All lines of evidence point to abnormalities of the mitochondria as the direct or indirect cause of LHON. Therefore, the mitochondria-LHON connection needs to be revisited and examined closely. This review will attempt to do that and provide an update on various aspects of LHON. PMID:21572729

Abu-Amero, Khaled K

2011-01-01

224

Evaluation of left ventricular systolic function revisited in septic shock.  

PubMed

The meta-analysis of Huang and coworkers failed to find any evidence for a protective effect of a decreased left ventricular (LV) ejection fraction (EF). These results have to be interpreted with caution since in most studies included in the meta-analysis patients with LV systolic dysfunction received inotropic drugs. We have some arguments suggesting that such a treatment may improve macrocirculation and microcirculation and finally prognosis. This paper allows us to clarify the meaning of LV function in septic shock patients. In all experimental models of septic shock using the load-independent parameter of LV systolic function, LV contractility impairment, called septic cardiomyopathy, has been reported to be constant. However, LVEF reflects the coupling between LV contractility and LV afterload. A normal LVEF may be observed when the arterial tone is severely depressed, as in septic shock, despite seriously impaired intrinsic LV contractility. LV systolic function, evaluated using an echocardiograph or another device, is then more a reflection of arterial tone (and its correction) than of intrinsic LV contractility. As a consequence, the incidence of LV systolic dysfunction greatly depends on the time of the evaluation, reflecting the fact that, during resuscitation and treatment, vasoplegia and then LV afterload are corrected, thus unmasking septic cardiomyopathy. With these points in mind, we can revisit the results of Margaret Parker's original study: it is not that the patients with a low EF survived better, but rather that the other patients had an increased mortality due to persistent profound vasoplegia. PMID:23826739

Repessé, Xavier; Charron, Cyril; Vieillard-Baron, Antoine

2013-01-01

225

Evaluation of left ventricular systolic function revisited in septic shock  

PubMed Central

The meta-analysis of Huang and coworkers failed to find any evidence for a protective effect of a decreased left ventricular (LV) ejection fraction (EF). These results have to be interpreted with caution since in most studies included in the meta-analysis patients with LV systolic dysfunction received inotropic drugs. We have some arguments suggesting that such a treatment may improve macrocirculation and microcirculation and finally prognosis. This paper allows us to clarify the meaning of LV function in septic shock patients. In all experimental models of septic shock using the load-independent parameter of LV systolic function, LV contractility impairment, called septic cardiomyopathy, has been reported to be constant. However, LVEF reflects the coupling between LV contractility and LV afterload. A normal LVEF may be observed when the arterial tone is severely depressed, as in septic shock, despite seriously impaired intrinsic LV contractility. LV systolic function, evaluated using an echocardiograph or another device, is then more a reflection of arterial tone (and its correction) than of intrinsic LV contractility. As a consequence, the incidence of LV systolic dysfunction greatly depends on the time of the evaluation, reflecting the fact that, during resuscitation and treatment, vasoplegia and then LV afterload are corrected, thus unmasking septic cardiomyopathy. With these points in mind, we can revisit the results of Margaret Parker's original study: it is not that the patients with a low EF survived better, but rather that the other patients had an increased mortality due to persistent profound vasoplegia. PMID:23826739

2013-01-01

226

Maturation of the human medial efferent reflex revisited  

PubMed Central

Past work applying otoacoustic emissions to gauge maturational status of the medial olivocochlear (MOC) reflex in human newborns has produced mixed results. The present study revisits the question while considering the dual nature of the 2f1 – f2 distortion product otoacoustic emission (DPOAE) and expanding measures of medial efferent function. Subjects included premature and term-born neonates, 6-month-old infants and young adults. The MOC reflex was elicited with contralateral acoustic stimulation (CAS) while shifts in amplitude and phase of the DPOAE, and its distortion and reflection components, were monitored. Overall, CAS-elicited reductions in DPOAE level did not differ among age groups. For all ages, the MOC reflex was strongest at frequencies below 1.5 kHz, and the reflection component of the DPOAE was most affected, showing maximally reduced amplitude and shallower phase slope when contralateral noise was presented. Results suggest that the MOC reflex likely reaches maturation prior to full-term birth. However, prematurely born neonates show markedly more episodes of CAS-induced DPOAE level enhancement. This may be due to more intrusive component mixing in this age group or disruptions in the formation of the MOC pathway or synapse in the most premature neonates. PMID:23363111

Abdala, Carolina; Mishra, Srikanta; Garinis, Angela

2013-01-01

227

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

228

Historical volcanoes of Armenia and adjacent areas: What is revisited?  

NASA Astrophysics Data System (ADS)

The validity of some data in Karakhanian et al. [Karakhanian, A., Djrbashian, R., Trifonov V., Philip H., Arakelian S., Avagian, A., 2002. Holocene-historical volcanism and active faults as natural risk factor for Armenia and adjacent countries. Journal of Volcanology and Geothermal Research, 113, 1, 319-344; Karakhanian, A., Jrbashyan, R., Trifonov, V., Philip, H., Arakelian, S., Avagyan, A., Baghdassaryan, H., Davtian, V., Ghoukassyan, Yu., 2003. Volcanic hazards in the region of the Armenian nuclear power plant. Journal of Volcanology and Geothermal Research, 126/1-2, 31-62] that are revisited by R. Haroutiunian is considered. A conclusion is made that the revisions suggested by Haroutiunian concern unessential parts of the content of work by Karakhanian et al. [Karakhanian, A., Djrbashian, R., Trifonov V., Philip H., Arakelian S., Avagian, A., 2002. Holocene-historical volcanism and active faults as natural risk factor for Armenia and adjacent countries. Journal of Volcanology and Geothermal Research, 113, 1, 319-344; Karakhanian, A., Jrbashyan, R., Trifonov, V., Philip, H., Arakelian, S., Avagyan, A., Baghdassaryan, H., Davtian, V., Ghoukassyan, Yu., 2003. Volcanic hazards in the region of the Armenian nuclear power plant. Journal of Volcanology and Geothermal Research, 126/1-2, 31-62]. This article presents new evidence and re-proves the earlier conclusions that are disputed or revised by R. Haroutiunian.

Karakhanian, A.; Jrbashyan, R.; Trifonov, V.; Philip, H.; Arakelian, S.; Avagyan, A.; Baghdassaryan, H.; Davtian, V.

2006-07-01

229

Revisited global drift fluid model for linear devices  

SciTech Connect

The problem of energy conserving global drift fluid simulations is revisited. It is found that for the case of cylindrical plasmas in a homogenous magnetic field, a straightforward reformulation is possible avoiding simplifications leading to energetic inconsistencies. The particular new feature is the rigorous treatment of the polarisation drift by a generalization of the vorticity equation. The resulting set of model equations contains previous formulations as limiting cases and is suitable for efficient numerical techniques. Examples of applications on studies of plasma blobs and its impact on plasma target interaction are presented. The numerical studies focus on the appearance of plasma blobs and intermittent transport and its consequences on the release of sputtered target materials in the plasma. Intermittent expulsion of particles in radial direction can be observed and it is found that although the neutrals released from the target show strong fluctuations in their propagation into the plasma column, the overall effect on time averaged profiles is negligible for the conditions considered. In addition, the numerical simulations are utilised to perform an a-posteriori assessment of the magnitude of energetic inconsistencies in previously used simplified models. It is found that certain popular approximations, in particular by the use of simplified vorticity equations, do not significantly affect energetics. However, popular model simplifications with respect to parallel advection are found to provide significant deterioration of the model consistency.

Reiser, Dirk [Institute for Energy and Climate Research-Plasma Physics, Research Center Juelich GmbH, Association FZJ-Euratom, D-52425 Juelich (Germany)

2012-07-15

230

How Black Holes Get Their Kicks: Gravitational Radiation Recoil Revisited  

NASA Astrophysics Data System (ADS)

Gravitational waves from the coalescence of binary black holes carry away linear momentum, causing center of mass recoil. This ``radiation rocket'' effect has important implications for systems with escape speeds of order the recoil velocity. We revisit this problem using black hole perturbation theory, treating the binary as a test mass spiraling into a spinning hole. For extreme mass ratios (q?m1/m2<<1), we compute the recoil for the slow in-spiral epoch of binary coalescence very accurately; these results can be extrapolated to q~0.4 with modest accuracy. Although the recoil from the final plunge contributes significantly to the final recoil, we are only able to make crude estimates of its magnitude. We find that the recoil can easily reach ~100-200 km s-1 but most likely does not exceed ~500 km s-1. Although much lower than previous estimates, this recoil is large enough to have important astrophysical consequences. These include the ejection of black holes from globular clusters, dwarf galaxies, and high-redshift dark matter halos.

Favata, Marc; Hughes, Scott A.; Holz, Daniel E.

2004-05-01

231

Mirror Instability in the Solar Wind: The Theory Revisited  

NASA Technical Reports Server (NTRS)

"Magnetic holes", localized depressions in the interplanetary magnetic field, have been identified in Ulysses data over a range of several AU and as far as 23 degrees south in latitude by Winterhalter et al., who concluded that these structures are most likely the remnants of structures caused by occasional mirror-mode instability in the solar wind. However, these authors, like a number of previous investigators, used the mirror stability criterion derived from the kinetic theory under very special assumptions. On the other hand, theoretical investigations using the fully self-consistent kinetic theory (Vlasov-Maxwell equations) have shown that the mirror stability criterion is more complicated when electrons and ions have different anisotropies, as is normally the case in the solar wind. Winterhalter et al used an instability criterion of the form R is greater than 1, where R is a function of the thermal anisotropy; the correct criterion (for bi-Maxwellian distributions) is R R is greater than 1 - x(exp 2), where x is a real quantity that depends on both the proton anisotropy and electron anisotropy. So nonzero x would modify the Winterhalter et al results in the direction of reinforcing their conclusions. We have revisited the instability criterion in its most general form, allowing for (a) non-Maxwellian velocity distributions, (b) multiple ion species, and (c) interparticle streaming. These results should give sound theoretical grounding for future observational studies related to the mirror instability, by Ulysses and other spacecraft.

Barnes, A.

1995-01-01

232

Changes in Sea Levels around the British Isles Revisited (Invited)  

NASA Astrophysics Data System (ADS)

Recently a number of new and/or updated sources for estimates of vertical land movements for the British Isles have become available allowing the relative and average changes in sea levels for this region to be revisited. The geodetic data set stems from a combination of re-processed continuous Global Positioning System (GPS) measurements from stations in the British Isles and from a global reference frame network, and absolute gravity (AG) measurements from two stations in the British Isles. The geologic data set of late Holocene sea level indicators has recently been updated, now applying corrections for the 20th century sea level rise, syphoning effect and late Holocene global ice melt, and expanded to Northern Ireland and Ireland. Several new model predictions of the glacial isostatic adjustment (GIA) process active in this region form the modelling data set of vertical land movements for the British Isles. Correcting the updated revised local reference (RLR) trends from the Permanent Service for Mean Sea Level (PSMSL) with these vertical land movement data sets, regional and averaged changes in sea levels around the British Isles have been investigated. Special focus is thereby also given to the coastal areas that have recently been identified within the UK Climate Projections 2009.

Teferle, F. N.; Hansen, D. N.; Bingley, R. M.; Williams, S. D.; Woodworth, P. L.; Gehrels, W. R.; Bradley, S. L.; Stocchi, P.

2009-12-01

233

Revisiting the Source Process of the 2007 Tocopilla, Chile Earthquake  

NASA Astrophysics Data System (ADS)

We revisit the 2007 Mw 7.7 Tocopilla, Chile earthquake to create a finite fault kinematic source model based on the current best practices in data analysis and inversion methods. The data used to constrain the source model include both static GPS offsets and 1 Hz kinematic GPS time series, as well as interferograms which have been reanalyzed to remove tropospheric effects which can be quite significant in this region. Our inversion methodology is a Bayesian approach that uses only physics-based constraints on the rupture evolution, and which utilizes models of both the observational noise and the errors in our forward model to obtain the ensemble of all plausible rupture models which satisfy both the data and our a priori assumptions. This approach allows us to better understand which parts of the rupture process are well-constrained and which are not, and thus to better understand how the 2007 Tocopilla, Chile earthquake rupture fits into the sequence of large earthquakes which have been mosaicking the northern Chile subduction zone.

Simons, M.; Minson, S. E.; Jolivet, R.; Jiang, J.; Beck, J. L.

2013-12-01

234

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

235

Dynamics of personality test responses: the empiricist's manifesto revisited.  

PubMed

This article revisits the classic empirical manifesto written by Meehl in 1945, and examines subsequent developments in structured personality assessment. The current status of personality assessment from an empirical-scale-development perspective is presented, with examples drawn from recent work on the MMPI-2. Meehl's heuristic defense of empirically based personality-scale construction was reexamined and the lasting influences of these views were highlighted. Meehl's early conceptualization of the relative unimportance of item content in personality-test construction and several alternative views were summarized, and Meehl's modified position was described. The role that test-taking attitudes can play in personality assessment was discussed in the 1945 article, and Meehl's views on the need for appraisal of invalidating conditions have been reaffirmed in contemporary test development. Finally, the so-called "dynamics" of a structured personality item response were discussed from a contemporary perspective, and some recent research was included to illustrate the continued importance of anchoring test interpretation in empirical correlates. PMID:10726673

Butcher, J N

2000-03-01

236

Storage coefficient revisited: is purely vertical strain a good assumption?  

PubMed

The storage coefficient that is used ubiquitously today was first defined by the analytical work of Theis and Jacob over a half-century ago. Inherent within this definition is the restriction of purely vertical compression of the aquifer during a reduction in pressure. The assumption is revisited and quantitatively evaluated by comparing numerical results using both one- and three-dimensional strain models in the presence of three-dimensional flow. Results indicate that (1) calculated hydraulic head values are nearly identical for both models; (2) the release of water from storage in terms of volume strain is nearly identical for both models and that the location of maximum production moves outward from the well as a function of time; (3) the vertical strain components are markedly different with at least 50% of the total volume of water pumped originating from horizontal strain (and increasing to as much as 70%); and (4) for the one-dimensional strain model to yield the necessary quantity of water to the pumped well, the resulting vertical compaction (land subsidence) is as much as four times greater and vertical strain is as much as 60% greater than the three-dimensional strain model. Results indicate that small changes in porosity resulting from horizontal strain can yield extremely large quantities of water to the pumping well. This study suggests that the assumption of purely vertical strain used in the definition of the storage coefficient is not valid. PMID:11341012

Burbey, T J

2001-01-01

237

Neural network modelling of CIMIS-ET0 (revisited)  

NASA Astrophysics Data System (ADS)

This paper will revisit the use of four independent hydrometeorological variables to predict 'reference crop evapotranspiration' in a neural network model - calculated as CIMIS-ET0 (Kisi, 2006; Aytek et al., 2008). The two earlier studies are coalesced and their published findings positioned in a broader environmental modelling context. Four models developed on similar datasets are compared and contrasted in the current exercise: a multiple linear regression model (MLIN: Pearson, 1896), a piecewise multiple linear regression model (M5 Model Tree; M5MT: Quinlan, 1992; Wang & Witten, 1997) and two neural network models developed on different optimisation algorithms - Conjugate Gradient (CGNN: Hestenes & Stiefel, 1952) and Levenberg-Marquet (LMNN: Levenberg, 1944; Marquardt, 1963). The results are presented using residual scatterplots so that the exact nature of the each individual modelling solution can be determined: permitting outputs to be interpreted in terms of structures, symmetries, orientations, local features and outliers. The reported inspection and interpretation of plots is matched against a selection of traditional numerical modelling statistics that were computed on HydroTest (http://www.hydrotest.org.uk; Dawson et al., 2007). The reported closeness of earlier neurocomputing outputs to predicted values estimated using a counterpart multiple linear regression model is explained in detail.

Abrahart, R. J.; Ghani, N. Ab

2009-04-01

238

Revisiting the naturalness problem: Who is afraid of quadratic divergences?  

NASA Astrophysics Data System (ADS)

It is widely believed that quadratic divergences severely restrict natural constructions of particle physics models beyond the standard model (SM). Supersymmetry provides a beautiful solution, but the recent LHC experiments have excluded large parameter regions of supersymmetric extensions of the SM. It will now be important to reconsider whether we have been misinterpreting the quadratic divergences in field theories. In this paper, we revisit the problem from the viewpoint of the Wilsonian renormalization group and argue that quadratic divergences—which can always be absorbed into a position of the critical surface—should be simply subtracted in model constructions. Such a picture gives another justification to the argument [W. A. Bardeen, Report No. FERMILAB-CONF-95-391-T] that the scale invariance of the SM, except for the soft-breaking terms, is an alternative solution to the naturalness problem. It also largely broadens possibilities of model constructions beyond the SM since we just need to take care of logarithmic divergences, which cause mixings of various physical scales and runnings of couplings.

Aoki, Hajime; Iso, Satoshi

2012-07-01

239

Cauchy-perturbative matching revisited: tests in spherical symmetry  

E-print Network

During the last few years progress has been made on several fronts making it possible to revisit Cauchy-perturbative matching (CPM) in numerical relativity in a more robust and accurate way. This paper is the first in a series where we plan to analyze CPM in the light of these new results. Here we start by testing high-order summation-by-parts operators, penalty boundaries and contraint-preserving boundary conditions applied to CPM in a setting that is simple enough to study all the ingredients in great detail: Einstein's equations in spherical symmetry, describing a black hole coupled to a massless scalar field. We show that with the techniques described above, the errors introduced by Cauchy-perturbative matching are very small, and that very long term and accurate CPM evolutions can be achieved. Our tests include the accretion and ring-down phase of a Schwarzschild black hole with CPM, where we find that the discrete evolution introduces, with a low spatial resolution of \\Delta r = M/10, an error of 0.3% after an evolution time of 1,000,000 M. For a black hole of solar mass, this corresponds to approximately 5 s, and is therefore at the lower end of timescales discussed e.g. in the collapsar model of gamma-ray burst engines. (abridged)

Burkhard Zink; Enrique Pazos; Peter Diener; Manuel Tiglio

2005-11-30

240

MERCURY CONCENTRATIONS IN LAKE SEDIMENTS REVISITING THE PREDICTIVE POWER OF CATCHMENT MORPHOMETRY AND  

E-print Network

MERCURY CONCENTRATIONS IN LAKE SEDIMENTS ­ REVISITING THE PREDICTIVE POWER OF CATCHMENT MORPHOMETRY@uvic.ca) (Received 21 April 2005; accepted 9 September 2005) Abstract. Lake sediments are a potential source for lake catchment morphometry and (b) organic matter composition of sediments in an effort to account

Long, Bernard

241

The Myth of Meeting Needs Revisited: The Case of Educational Research  

ERIC Educational Resources Information Center

Our primary objective in this paper is revisit a debate that was articulated 25 years ago in this journal in which it was argued that the idea of meeting needs in adult and continuing education is a myth. We extend the original analysis of need and apply it to the case of educational research. We look at the policy context, which has, in the…

Lawy, Robert; Armstrong, Paul

2009-01-01

242

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

243

Relative Age Effects and the PhD 1 Revisiting Gladwell's Hockey Players  

E-print Network

Relative Age Effects and the PhD 1 Revisiting Gladwell's Hockey Players: Influence of Relative Age involving Canadian hockey players to popularize the concept of "redshirting" kindergarten-aged children by the order of their selection in the National Hockey League (NHL) draft � than children who were always

Danforth, Bryan Nicholas

244

The Anatomy and Physiology of the Grid Revisited Chris A. Mattmann1,2  

E-print Network

related such technologies. The first, OODT [7], is a data grid platform currently in use at NASA California Institute of Technology Pasadena, CA 91109, USA mattmann@jpl.nasa.gov Abstract A domain software systems within a given appli- cation domain. In this paper, we revisit the widely cited DSSA

Mattmann, Chris

245

Revisiting the Accuracy Hypothesis in Families of Young Children With Conduct Problems  

Microsoft Academic Search

Revisited the accuracy hypothesis in an examination of the relation between maternal depressive symptomatology and child conduct problems. All data were gathered as part of the pretreatment assessment in an outcome study of families with clinic-re - ferred children with conduct problems (age 3 to 6). The mothers varied in their depres - sive symptomatology, from not at all symptomatic

Jane G. Querido; Sheila M. Eyberg; Stephen R. Boggs

2001-01-01

246

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

E-print Network

Media Equation revisited. Do users show polite reactions towards an embodied agent? Laura Hoffmann1 they were asked to evaluate the ECA. Additionally, user variables (e.g. gender, computer literacy) show an impact on the on the evaluation of the ECA. Keywords: evaluation study, social effects, politeness, media

Kopp, Stefan

247

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

248

Resampling Methods Revisited: Advancing the Understanding and Applications in Educational Research  

ERIC Educational Resources Information Center

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…

Bai, Haiyan; Pan, Wei

2008-01-01

249

REVISITING THE VARIANCE-BASED SELECTION MODEL OF DIPLOID DRONE PRODUCTION FOR MULTIPLE MATING IN  

E-print Network

REVISITING THE VARIANCE-BASED SELECTION MODEL OF DIPLOID DRONE PRODUCTION FOR MULTIPLE MATING with comprehensive theoretical analysis lacking behind. We report on the mathematical analysis of the diploid drone mating does not reduce the average value of diploid drone production but reduces its variance. We combine

Saidak, Filip

250

Plasmon-Assisted Two-Slit Transmission: Young's Experiment Revisited H. F. Schouten,1  

E-print Network

Plasmon-Assisted Two-Slit Transmission: Young's Experiment Revisited H. F. Schouten,1 N. Kuzmin,2 G perforated by two subwavelength slits, separated by many optical wavelengths. The total intensity of the far of at the detector. The interference arises as a consequence of the excitation of surface plasmons propagating from

Visser, Taco D.

251

Sputnik and ‘skill thinking’ revisited: technological determinism in American responses to the Soviet missile threat  

Microsoft Academic Search

Revisiting popular, political and academic reactions 50 years after the launch of Sputnik, this article seeks to highlight the substantial fear of technological development evident in these reactions. The nature of responses to Sputnik is especially notable, it is argued, in light of the tendency to assume an American love affair with technology across all areas of social and political

Columba Peoples

2008-01-01

252

Author's personal copy Revisiting dirt cracking as a physical weathering process in warm deserts  

E-print Network

- envisioned dirt-cracking wedging process starts with calcium carbonate precipitating in ssures less than 5 m pressure to widen and deepen the ssure, allowing the carbonate precipitation process to penetrate evenAuthor's personal copy Revisiting dirt cracking as a physical weathering process in warm deserts

Dorn, Ron

253

Distance Learning Revisited: Life-Long Learning and the National Information Infrastructure.  

ERIC Educational Resources Information Center

This paper "revisits" distance learning by addressing its past achievements, its present state, and its future in the face of the rapidly converging computer and communications technologies and the goals and potential that underlie the creation of the proposed National Information Infrastructure (NII). The analysis was undertaken recognizing that…

Weisburg, Michael; Ullmer, Eldon J.

254

Revisiting the protein-coding gene catalog of Drosophila melanogaster using 12 fly genomes  

E-print Network

Revisiting the protein-coding gene catalog of Drosophila melanogaster using 12 fly genomes Michael as Drosophila melanogaster. [Supplemental material is available online at www.genome.org. Additional understanding the functional elements in any genome. In Drosophila melanogaster, a century of classical genetics

Kellis, Manolis

255

Revisiting the protein-coding gene catalog of Drosophila melanogaster using twelve fly genomes  

E-print Network

1 Revisiting the protein-coding gene catalog of Drosophila melanogaster using twelve fly genomes of sequenced genomes from 12 Drosophila species has enabled the use of comparative genomics for the systematic,193 candidate new protein-coding exons in the D. melanogaster genome. We have both reviewed these predictions

Kellis, Manolis

256

Gender Differences in Self-Reports of Depression: The Response Bias Hypothesis Revisited  

Microsoft Academic Search

This study was designed to revisit the response bias hypothesis, which posits that gender differences in depression prevalence rates may reflect a tendency for men to underreport depressive symptoms. In this study, we examined aspects of gender role socialization (gender-related traits, socially desirable responding, beliefs about mental health and depression) that may contribute to a response bias in self-reports of

Sandra T. Sigmon; Jennifer J. Pells; Nina E. Boulard; Stacy Whitcomb-Smith; Teresa M. Edenfield; Barbara A. Hermann; Stephanie M. LaMattina; Janell G. Schartel; Elizabeth Kubik

2005-01-01

257

Recreancy Revisited: Beliefs about Institutional Failure Following the Exxon Valdez Oil Spill  

Microsoft Academic Search

In 1993, Freudenburg suggested the term “recreancy” to refer to behaviors associated with institutional failures, which he distinguished from the consequences of such failures. This article revisits issues related to recreancy associated with the 1989 Exxon Valdez oil spill. Using qualitative data collected in Cordova, Alaska, between 2002 and 2010, we examine notions about recreancy and technological disasters. Findings highlight

Liesel Ashley Ritchie; Duane A. Gill; Courtney N. Farnham

2012-01-01

258

Revisiting the Influence of the Quasi-Biennial Oscillation on Tropical Cyclone Activity  

E-print Network

al. 2010), the Atlantic multidecadal oscillation (AMO; Goldenberg et al. 2001; Zhang and DelworthRevisiting the Influence of the Quasi-Biennial Oscillation on Tropical Cyclone Activity SUZANA J form 7 June 2010) ABSTRACT The statistical relationship between the quasi-biennial oscillation (QBO

Sobel, Adam

259

Preschool in Three Cultures Revisited: China, Japan, and the United States  

ERIC Educational Resources Information Center

Published twenty years ago, the original "Preschool in Three Cultures" was a landmark in the study of education: a profoundly enlightening exploration of the different ways preschoolers are taught in China, Japan, and the United States. Here, lead author Joseph Tobin--along with new collaborators Yeh Hsueh and Mayumi Karasawa--revisits his…

Tobin, Joseph; Hsueh, Yeh; Karasawa, Mayumi

2009-01-01

260

Revisiting nutrient utilization in the glacial Antarctic: Evidence from a new method for diatom-bound  

E-print Network

Revisiting nutrient utilization in the glacial Antarctic: Evidence from a new method for diatom Antarctic: Evidence from a new method for diatom-bound N isotopic analysis, Paleoceanography, 19, PA3001; accepted 16 April 2004; published 1 July 2004. [1] Isotopic measurements of diatom-bound nitrogen, using

Sigman, Daniel M.

261

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

262

Static Query Result Caching Revisited Rifat Ozcan, Ismail Sengor Altingovde, zgr Ulusoy  

E-print Network

Static Query Result Caching Revisited Rifat Ozcan, Ismail Sengor Altingovde, �zgür Ulusoy first review several query features that are used to determine the contents of a static result cache and effectiveness). General Terms Performance, Experimentation. Keywords Search engine, static caching, query result

Ulusoy, �zgür

263

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.

264

Teacher Leadership and Pupil Reaction: the Authoritarian?Democratic Dimension Revisited  

Microsoft Academic Search

Rian, H. (1969). Teacher Leadership and Pupil Reaction: The Authoritarian Democratic Dimension Revisited. Pedagogisk Forskning, Scand. J. Educ. Res. 13, 1?15. The purpose of the study was 1) to make an experimental comparison between the effects of directive and non?directive teacher leadership on pupil achievement and satisfaction, and 2) to explore possible interactions between teacher leadership patterns and a) pupil

Håvard Rian

1969-01-01

265

Plasma and Fusion Research: Regular Articles Vol. 4 (2009) Adiabatic Wave-Particle Interaction Revisited  

E-print Network

Revisited Robert L. DEWAR1,2) and Justin C.-C. YAP1) 1) Plasma Research Laboratory and Dept. of Theoretical that the wave frame is noninertial if is author's e-mail: robert.dewar@anu.edu.au time-dependent.) The equation

Dewar, Robert L.

266

Unstable Escherichia coli L-forms revisited:4 growth requires peptidoglycan synthesis5  

E-print Network

1 1 2 3 Unstable Escherichia coli L-forms revisited:4 growth requires peptidoglycan synthesis5 of a wild type Escherichia coli K-12 strain overnight to a growing5 L-form-like state, using the -lactam L-forms require, using Escherichia coli K-12 as model.8 Septal synthesis is carried out

Paris-Sud XI, Université de

267

Monetary Policy in the Open Economy Revisited: The Case for Exchange-Rate Flexibility Restored  

E-print Network

Monetary Policy in the Open Economy Revisited: The Case for Exchange-Rate Flexibility Restored of an expenditure-switching role of exchange rate changes. Keywords: optimal monetary policy, exchange rate home and foreign goods and lends a stabilization role to exchange rates in the face of country

Sadoulet, Elisabeth

268

Revisiting the van Trees inequality in the spirit of Hajek and Le Cam Elisabeth Gassiat  

E-print Network

Revisiting the van Trees inequality in the spirit of H´ajek and Le Cam Elisabeth Gassiat form and under minimal assumptions, in the spirit of H´ajek and Le Cam. We prove that the van Trees in the spirit of H´ajek and Le Cam 1. Introduction A long story made short. Once upon a time (in April 2001

Gassiat, Elisabeth

269

Revisiting Feminism and Australian Education: Who Speaks? What Questions? What Contexts? What Impact?  

ERIC Educational Resources Information Center

This article revisits the development of feminist research and policy in education in Australia in the mid-1970s to mid-1980s from the perspective of the present decade. The purpose is to give one insider's account of the specificities of that initial period, and to use that analysis to draw attention to changes evident in the context and agendas…

Yates, Lyn

2008-01-01

270

ALUMINUM SITING IN THE ZSM-22 AND THETA-1 ZEOLITES REVISITED: A QM/MM STUDY  

E-print Network

ALUMINUM SITING IN THE ZSM-22 AND THETA-1 ZEOLITES REVISITED: A QM/MM STUDY Stepan SKLENAKa1 structure was investigated analyzing already published 27 Al 3Q MAS NMR experimental data using QM with the majority of Al at- oms in the TON structure exhibit a significantly limited reaction space. The 27 Al NMR

Sklenak, Stepan

271

Revisiting the Layer/Mask Paradigm for Augmented Scenery Christian Jacquemin12  

E-print Network

domains of cultural life, are influenced by the developments of digital media and their possible useRevisiting the Layer/Mask Paradigm for Augmented Scenery Christian Jacquemin12 and Georges Gagneré Carnot 93300 Aubervilliers gg@didascalie.net Bios Christian Jacquemin is a Professor in Computer Science

Jacquemin, Christian

272

REVISITING THE SECURITY OF SPEAKER VERIFICATION SYSTEMS AGAINST IMPOSTURE USING SYNTHETIC SPEECH  

E-print Network

-likelihood ratio (X) is computed by scoring the sequence of test feature vectors X = {x1, . . . , xM } againstREVISITING THE SECURITY OF SPEAKER VERIFICATION SYSTEMS AGAINST IMPOSTURE USING SYNTHETIC SPEECH. We use two SV systems: standard GMM- UBM-based and a newer SVM-based. Our results show when

De Leon, Phillip

273

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

274

Unplanned Emergency Department Revisits within 72 Hours to a Secondary Teaching Referral Hospital in Taiwan  

Microsoft Academic Search

Background: When patients return to the emergency department (ED) shortly after being seen, it is generally assumed that their initial evaluation or treatment was inadequate. Objectives: The purpose of this study was to determine the rates and causes of revisits to the ED of a 710-bed secondary teaching referral hospital (Kuang Tien General Hospital), to identify areas for improvement, and

Chiu-Lung Wu; Fa-Tsai Wang; Yao-Chiu Chiang; Yuan-Fa Chiu; Teong-Giap Lin; Lian-Fong Fu; Tsung-Lung Tsai

2010-01-01

275

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 (e-mail." seranne@dstu, univ-montp2.fr) Abstract: The Gulf of Lion margin is one of the Tertiary and the geodynamic setting of the margin within the Western Mediterranean. IBS-Gulf of Lion research was based

Demouchy, Sylvie

276

Benign and Benevolent Conquest?: The Ideology of Elizabethan Atlantic Expansion Revisited  

Microsoft Academic Search

:This essay revisits the language of conquest in metropolitan writings advocating Elizabethan Atlantic expansion. It argues that contrary to the belligerent connotations scholars usually attach to the word conquest, in Elizabethan England it was a term used in a benign and benevolent manner that fit within humanist goals for a noble, peaceful, and long-term relationship with both the people and

Ken MacMillan

2011-01-01

277

Benign and Benevolent Conquest?: The Ideology of Elizabethan Atlantic Expansion Revisited  

Microsoft Academic Search

This essay revisits the language of conquest in metropolitan writings advocating Elizabethan Atlantic expansion. It argues that contrary to the belligerent connotations scholars usually attach to the word conquest, in Elizabethan England it was a term used in a benign and benevolent manner that fit within humanist goals for a noble, peaceful, and long-term relationship with both the people and

Ken MacMillan

2011-01-01

278

Revisiting Levy flight search patterns of wandering albatrosses, bumblebees and deer  

E-print Network

LETTERS Revisiting Le´vy flight search patterns of wandering albatrosses, bumblebees and deer about the search strategies of deer10 and bumblebees10 . These pioneering studies have triggered much weights19,20 . We apply this to the four original deer and bumblebee data sets10 , finding that none

Stanley, H. Eugene

279

DNA as Genetic Material: Revisiting Classic Experiments through a Simple, Practical Class  

ERIC Educational Resources Information Center

In 1928, Frederick Griffith demonstrated a transmission process of genetic information by transforming "Pneumococcus". In 1944, Avery et al. demonstrated that Griffith's transforming principle was DNA. We revisited these classic experiments in a practical class for undergraduate students. Both experiments were reproduced in simple, adapted forms.…

Malago, Wilson, Jr.; Soares-Costa, Andrea; Henrique-Silva, Flavio

2009-01-01

280

Revisiting Evidence for Modularity and Functional Equivalence across Verbal and Spatial Domains in Memory  

ERIC Educational Resources Information Center

The authors revisited evidence in favor of modularity and of functional equivalence between the processing of verbal and spatial information in short-term memory. This was done by investigating the patterns of intrusions, omissions, transpositions, and fill-ins in verbal and spatial serial recall and order reconstruction tasks under control,…

Guerard, Katherine; Tremblay, Sebastien

2008-01-01

281

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

282

Short Communication Revisit on the evolutionary relationship between alternative splicing and  

E-print Network

Short Communication Revisit on the evolutionary relationship between alternative splicing and gene for Evolutionary Biology, School of Life Sciences, Fudan University, Shanghai 200433, China b Department duplication Alternative splicing Copy number variation Exon­intron structure Gene duplications and alternative

Gu, Xun

283

Fall Semester: A Time for Parents to Revisit Discussions About College Drinking  

E-print Network

Fall Semester: A Time for Parents to Revisit Discussions About College Drinking As college students), the consequences of excessive drinking by college students are more significant, more destructive, and more costly from this report, which were updated recently, indicate that drinking by college students aged 18 to 24

Bezrukov, Sergey M.

284

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

285

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

286

Sunday School Revisited: An Alternative to Christian Education of the Church Today?  

ERIC Educational Resources Information Center

This article attempts to demonstrate similarities between the socioeconomic, cultural, and religious contexts of 18th-century England and 21st-century Canada. Revisiting the Sunday School movement in 18th-century England provides insights for the development of renewed Sunday School models in the current Canadian context of transnational…

Song, Nam Soon

2013-01-01

287

ISRP 2002-9 Moses Lake Revisited Independent Scientific Review Panel  

E-print Network

ISRP 2002-9 Moses Lake Revisited 1 Independent Scientific Review Panel for the Northwest Power MEMORANDUM TO: Council Members FROM: Rick Williams, ISRP Chair SUBJECT: ISRP Review of Revised Moses Lake Recreational Fishery Proposal, Factors Affecting the Recreational Fishery in Moses Lake, Washington; - formerly

288

Tickets and Currencies Revisited: Extensions to Multi-Resource Lottery Scheduling  

E-print Network

Tickets and Currencies Revisited: Extensions to Multi-Resource Lottery Scheduling David G. Sullivan, Robert Haas, Margo I. Seltzer Harvard University Abstract Lottery scheduling's ticket and currency management framework developed for lottery scheduling [10, 11, 12] provides a means for resource allocation

289

Tickets and Currencies Revisited: Extensions to MultiResource Lottery Scheduling  

E-print Network

Tickets and Currencies Revisited: Extensions to Multi­Resource Lottery Scheduling David G. Sullivan, Robert Haas, Margo I. Seltzer Harvard University Abstract Lottery scheduling's ticket and currency management framework developed for lottery scheduling [10, 11, 12] provides a means for resource allocation

290

Measurement Program Success Factors Revisited Frank Niessink and Hans van Vliet  

E-print Network

Measurement Program Success Factors Revisited Frank Niessink and Hans van Vliet Division.vu.nl Abstract Success factors for measurement programs as identified in the literature typically focus on the `internals' of the measurement program: incremental implementation, support from manage- ment, a well

van Vliet, Hans

291

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

292

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

293

ArmstrongMcGehee mechanism revisited: Competitive exclusion and coexistence of nonlinear consumers  

E-print Network

Armstrong­McGehee mechanism revisited: Competitive exclusion and coexistence of nonlinear consumers logistically growing resource and two nonlinear consumers. Both the potential coexistence region and realized consumers. Non-monotonic changes occur at high nonlinearity due to reduced parameter space. a r t i c l e i

Fussman, Gregor

294

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

295

The Beam_Optics at the Extraction Region of SNS Ring: Revisited  

E-print Network

all fourteen kickers fire. The beam displacement is below the median plane of the ring. Beam Optics of the Extraction Region The single beam bunch circulating in the SNS ring is extracted in one turn, upon firing allThe Beam_Optics at the Extraction Region of SNS Ring: Revisited BNL/SNS TECHNICAL NOTE NO. 141 N

296

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

297

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

298

Production, Manufacturing and Logistics Bucket brigades revisited: Are they always effective?  

E-print Network

. There are no additional WIP buffers kept. The number of machines in a TSS line typically ranges from 2 to 16Production, Manufacturing and Logistics Bucket brigades revisited: Are they always effective architectures of this kind. TSS is employed regularly by manufacturers of sewn products in modules that are used

Armbruster, Dieter

299

Revisiting Imaging Features and the Embryologic Basis of Third and Fourth Branchial Anomalies  

Microsoft Academic Search

BACKGROUND AND PURPOSE: There is wide discrepancy between common clinical and radiologic presentations of branchial sinuses arising from the pyriform fossa and the theoretic course of third and fourth branchial arch anomalies. The purpose of this study was to revisit the clinical presentations and imaging features of such anomalies in children. MATERIALS AND METHODS: A retrospective review of institutional and

B. Thomas; M. Shroff; V. Forte; S. Blaser; A. James

2009-01-01

300

Revisiting imaging features and the embryologic basis of third and fourth branchial anomalies  

Microsoft Academic Search

BACKGROUND AND PURPOSE: There is wide discrepancy between common clinical and radiologic presentations of branchial sinuses arising from the pyriform fossa and the theoretic course of third and fourth branchial arch anomalies. The purpose of this study was to revisit the clinical presentations and imaging features of such anomalies in children. MATERIALS AND METHODS: A retrospective review of institutional and

B. Thomas; M. Shroff; V. Forte; S. Blaser; A. James

2010-01-01

301

Revisiting High School Conversions: What is Sustained After the Funding Goes?  

ERIC Educational Resources Information Center

School reformers hope that converting comprehensive high schools into collections of small schools will produce results similar to those realized in freestanding small schools. This comparative case study revisits two "conversions" as they complete the grant funding that supported the reform, in order to explore the extent to which changes…

Wallach, Catherine A.

2009-01-01

302

Revisiting shock-driven exploding pushers: Insights into plasma flows and fields, stopping power, nucleosynthesis, and  

E-print Network

Revisiting shock-driven exploding pushers: Insights into plasma flows and fields, stopping power of Technology 77 Massachusetts, Ave., Cambridge, MA 02139 USA E-mail: petrasso@psfc.mit.edu Abstract. Shock variety of experiments for radiographs of plasma-flow dynamics and self-generated fields in plasma jet

303

Gender Differences in End-User Debugging, Revisited: What the Miners Found  

E-print Network

Gender Differences in End-User Debugging, Revisited: What the Miners Found Valentina Grigoreanu to uncover gender differences in the ways males and females problem solve in end-user programming situations Although there has been a fairly wide interest in gender differences in computing professions and education

Fern, Xiaoli Zhang

304

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

305

Validation of SeaWiFS chlorophyll a concentrations in the Southern Ocean: A revisit  

E-print Network

Validation of SeaWiFS chlorophyll a concentrations in the Southern Ocean: A revisit Marina Marrari 15 July 2006 Abstract Surface chlorophyll a concentrations (Ca, mg m-3 ) in the Southern Ocean be attributed to the relatively low concentrations of chlorophyll b (Cb/Ca =0.023±0.034, n=482) and relatively

Daly, Kendra L.

306

Revisiting synchronous gamete release by fucoid algae in the intertidal zone: fertilization success and beyond?  

E-print Network

Revisiting synchronous gamete release by fucoid algae in the intertidal zone: fertilization success fertilization and settlement are critical processes linking adult and early juvenile life-history phases. This review focuses on synchronous gamete release (¼ spawning) in fucoid algae. These brown macroalgae

Teixeira, Sara

307

Where Traffic meets DNA: Mobility Mining using Biological Sequence Analysis Revisited  

E-print Network

Copyright 2011 ACM 978-1-4503-1031-4/11/11 ...$10.00. an attempt to improve human health, guide trafficWhere Traffic meets DNA: Mobility Mining using Biological Sequence Analysis Revisited Ahmed Jawad, Germany firstname.lastname@iais.fraunhofer.de ABSTRACT Traffic and mobility mining are fascinating

Kersting, Kristian

308

HIV-1 dynamics revisited: biphasic decay by cytotoxic T lymphocyte killing?  

E-print Network

HIV-1 dynamics revisited: biphasic decay by cytotoxic T lymphocyte killing? Ramy A. Arnaout1 treated for human immunode¢ciency virus type 1 (HIV-1) infection has been explained as the decay of two infections. Keywords: human immunode¢ciency virus (HIV); hepatitis C virus (HCV); mathematical model

Nowak, Martin A.

309

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

310

THE GEISSER-LEVINE METHOD REVISITED AND ALGEBRAIC CYCLES OVER A FINITE FIELD  

E-print Network

THE GEISSER-LEVINE METHOD REVISITED AND ALGEBRAIC CYCLES OVER A FINITE FIELD BRUNO KAHN Abstract. We reformulate part of the arguments of T. Geisser and M. Levine, and shows that the Geisser-Levine method can be applied generally to compare motivic cohomology

311

THE GEISSER-LEVINE METHOD REVISITED AND ALGEBRAIC CYCLES OVER A FINITE FIELD  

E-print Network

THE GEISSER-LEVINE METHOD REVISITED AND ALGEBRAIC CYCLES OVER A FINITE FIELD BRUNO KAHN Abstract. We reformulate part of the arguments of T. Geisser and M. Levine relating motivic cohomology amounts to a uniqueness theorem for motivic coho- mology, and shows that the Geisser-Levine method can

312

THE GEISSER-LEVINE METHOD REVISITED Abstract. We reformulate part of the arguments of T. Geisser  

E-print Network

THE GEISSER-LEVINE METHOD REVISITED BRUNO KAHN Abstract. We reformulate part of the arguments of T. Geisser and M. Levine computing motivic cohomology with finite coeffi- cients under the assumption cohomology, and shows that the Geisser-Levine method can be applied generally to compare motivic cohomology

313

Acoustic scattering from a thermally driven buoyant plume revisited John Oeschger  

E-print Network

Acoustic scattering from a thermally driven buoyant plume revisited John Oeschger Coastal Systems and L. Goodman, JASA, Acoustic scattering 1 #12;Far-field weak scattering theory is applied to the case of high frequency broadbandwidth acoustic scattering from a thermally generated buoyant plume

Goodman, Louis

314

Modular Ontology Languages Revisited Bernardo Cuenca-Grau and Oliver Kutz  

E-print Network

be processed, it may still be the case that the processing time involved is too high for ontology engineering in order to assist the ontology engineer in performing these tasks. We distinguish two ap- proachesModular Ontology Languages Revisited Bernardo Cuenca-Grau and Oliver Kutz The University

Grau, Bernardo Cuenca

315

Large Torsional Oscillations in Suspension Bridges Revisited: Fixing an Old Approximation Author(s): P. J. McKenna  

E-print Network

Large Torsional Oscillations in Suspension Bridges Revisited: Fixing an Old Approximation Author to The American Mathematical Monthly. http://www.jstor.org #12;LargeTorsionalOscillations in SuspensionBridges

McKenna, Joseph

316

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.

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

2014-01-01

317

Distant future of the Sun and Earth revisited  

E-print Network

We revisit the distant future of the Sun and the solar system, based on stellar models computed with a thoroughly tested evolution code. For the solar giant stages, mass-loss by the cool (but not dust-driven) wind is considered in detail. Using the new and well-calibrated mass-loss formula of Schroder & Cuntz (2005, 2007), we find that the mass lost by the Sun as an RGB giant (0.332 M_Sun, 7.59 Gy from now) potentially gives planet Earth a significant orbital expansion, inversely proportional to the remaining solar mass. According to these solar evolution models, the closest encounter of planet Earth with the solar cool giant photosphere will occur during the tip-RGB phase. During this critical episode, for each time-step of the evolution model, we consider the loss of orbital angular momentum suffered by planet Earth from tidal interaction with the giant Sun, as well as dynamical drag in the lower chromosphere. We find that planet Earth will not be able to escape engulfment, despite the positive effect of solar mass-loss. In order to survive the solar tip-RGB phase, any hypothetical planet would require a present-day minimum orbital radius of about 1.15 AU. Furthermore, our solar evolution models with detailed mass-loss description predict that the resulting tip-AGB giant will not reach its tip-RGB size. The main reason is the more significant amount of mass lost already in the RGB phase of the Sun. Hence, the tip-AGB luminosity will come short of driving a final, dust-driven superwind, and there will be no regular solar planetary nebula (PN). But a last thermal pulse may produce a circumstellar (CS) shell similar to, but rather smaller than, that of the peculiar PN IC 2149 with an estimated total CS shell mass of just a few hundredths of a solar mass.

Klaus-Peter Schroder; Robert C. Smith

2008-01-25

318

Revisiting the doping requirement for low power junctionless MOSFETs  

NASA Astrophysics Data System (ADS)

In this work, we revisit the requirement of higher channel doping (?1019 cm-3) in junctionless (JL) double gate MOSFETs. It is demonstrated that moderately doped (1018 cm-3) ultra low power (ULP) JL transistors perform significantly better than heavily doped (1019 cm-3) devices. JL MOSFETs with moderate doping results in the spreading out of carriers across the entire silicon film instead of being localized at the center of the film. This improves gate controllability leading to higher on-off current ratio and lower intrinsic delay for ULP subthreshold logic applications. Additional benefits of using a channel doping concentration of 1018 cm-3 instead of conventional heavily doped design is the significant reduction in threshold voltage sensitivity values (by ˜70-90%) with respect to film thickness and gate oxide thickness. Further improvement in ULP performance metrics can be achieved by limiting the source/drain implantation away from the gate edge. This design, specifically for ULP, allows the requirement of gate workfunction to be reduced from p+-poly (˜ 5.1 eV) to near about midgap values (˜ 4.8 eV). On-off current ratio and intrinsic delay for optimized JL devices are compared for low standby power projections of the technological roadmap. A 6T-SRAM cell operating at 0.8 V with 25 nm JL devices exhibits a static noise margin of 151 mV with gate workfunction offset of 0.2 eV with respect to midgap value (4.72 eV). The results highlight new viewpoints for realizing improved low power JL transistors.

Singh Parihar, Mukta; Kranti, Abhinav

2014-07-01

319

Richards model revisited: validation by and application to infection dynamics.  

PubMed

Ever since Richards proposed his flexible growth function more than half a century ago, it has been a mystery that this empirical function has made many incredible coincidences with real ecological or epidemic data even though one of its parameters (i.e., the exponential term) does not seem to have clear biological meaning. It is therefore a natural challenge to mathematical biologists to provide an explanation of the interesting coincidences and a biological interpretation of the parameter. Here we start from a simple epidemic SIR model to revisit Richards model via an intrinsic relation between both models. Especially, we prove that the exponential term in the Richards model has a one-to-one nonlinear correspondence to the basic reproduction number of the SIR model. This one-to-one relation provides us an explicit formula in calculating the basic reproduction number. Another biological significance of our study is the observation that the peak time is approximately just a serial interval after the turning point. Moreover, we provide an explicit relation between final outbreak size, basic reproduction number and the peak epidemic size which means that we can predict the final outbreak size shortly after the peak time. Finally, we introduce a constraint in Richards model to address over fitting problem observed in the existing studies and then apply our method with constraint to conduct some validation analysis using the data of recent outbreaks of prototype infectious diseases such as Canada 2009 H1N1 outbreak, GTA 2003 SARS outbreak, Singapore 2005 dengue outbreak, and Taiwan 2003 SARS outbreak. Our new formula gives much more stable and precise estimate of model parameters and key epidemic characteristics such as the final outbreak size, the basic reproduction number, and the turning point, compared with earlier simulations without constraints. PMID:22889641

Wang, Xiang-Sheng; Wu, Jianhong; Yang, Yong

2012-11-21

320

Inhibition of Apurinic/apyrimidinic endonuclease I's redox activity revisited  

PubMed Central

The essential base excision repair protein, apurinic/apyrimidinic endonuclease 1 (APE1), plays an important role in redox regulation in cells and is currently targeted for development of cancer therapeutics. One compound that binds APE1 directly is (E)-3-(2-(5,6-dimethoxy-3-methyl-1,4-benzoquinonyl))-2-nonyl propenoic acid (E3330). Here, we revisit the mechanism by which this negatively charged compound interacts with APE1 and inhibits its redox activity. At high concentrations (mM), E3330 interacts with two regions in the endonuclease active site of APE1, as mapped by hydrogen/deuterium exchange mass spectrometry. However, this interaction lowers the melting temperature of APE1 consistent with a loss of structure in APE1, as measured by both differential scanning fluorimetry and circular dichroism. These results are consistent with other findings that concentrations of E3330 greater than 100 ?M are required to inhibit APE1’s endonuclease activity. To determine the role of E3330’s negatively charged carboxylate in redox inhibition, we converted the carboxylate to an amide by synthesizing (E)-2-((4,5-dimethoxy-2-methyl-3,6-dioxocyclohexa-1,4-dien-1-yl)methylene)-N-methoxy-undecanamide (E3330-amide), a novel uncharged derivative. E3330-amide has no effect on the melting temperature of APE1, suggesting that it does not interact with the fully-folded protein. However, E3330-amide inhibits APE1’s redox activity in in vitro EMSA redox and cell-based transactivation assays producing lower IC50 values as compared to E3330, 8.5 ?M vs. 20 ?M and 7 ?M vs. 55 ?M, respectively. Thus, E3330’s negatively charged carboxylate is not required for redox inhibition. Collectively, our results provide additional support for a mechanism of redox inhibition involving interaction of E3330 or E3330-amide with partially unfolded APE1. PMID:23597102

Zhang, Jun; Luo, Meihua; Marasco, Daniela; Logsdon, Derek; LaFavers, Kaice A.; Chen, Qiujia; Reed, April; Kelley, Mark R.; Gross, Michael L.; Georgiadis, Millie M.

2013-01-01

321

Revisiting the solid HDO/H2O abundances  

NASA Astrophysics Data System (ADS)

We revisit the reported detection and upper limits on HDO in ice mantles present in the molecular cloud environments of the massive young protostars Gl 2136 and W33 A, using independent VLT-ISAAC and UKIRT-CGS4 spectroscopic observations. We also present VLT and UKIRT spectra of RAFGL 7009 near the HDO absorption wavelength and reanalyze the ISO-SWS spectral data for NGC 7538 IRS9, Orion-BN and S140. We demonstrate that the previously reported detections of HDO in W33 A and NGC 7538 IRS9 are incorrect. We present an in-depth analysis that shows that, besides the sensitivity limits, detection of low levels of HDO is difficult in amorphous ice mantles when features from solid methanol, a common grain mantle constituent, are present. We discuss the specific problems arising in the ISO data in this wavelength range for NGC 7538 IRS9. Using VLT-ISAAC observations, we also investigate the HDO/H2O ratio toward the intermediate mass stars IRAS 05329-0728 and IRAS 08448-4343. Our derived upper limits for the D/H ratio in water ice range from HDO/H2O < 1% to 0.2% in the different sources, and we discuss these limits in comparison with values derived in other environments. Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO Programme 164.I-0605(A)), UKIRT, Mauna Kea, Hawaii, and ISO satellite. The United Kingdom Infrared Telescope is operated by the Joint Astronomy Centre on behalf of the UK Particle Physics and Astronomy Research Council. TRG's research is supported by the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., on behalf of the international Gemini partnership of Argentina, Australia, Brazil, Canada, Chile, the UK, and the USA.

Dartois, E.; Thi, W.-F.; Geballe, T. R.; Deboffle, D.; d'Hendecourt, L.; van Dishoeck, E.

2003-03-01

322

Revisiting the sequencing of the first tree genome: Populus trichocarpa.  

PubMed

Ten years ago, it was announced that the Joint Genome Institute with funds provided by the Department of Energy, Office of Science, Biological and Environmental Research would sequence the black cottonwood (Populus trichocarpa Torr. & Gray) genome. This landmark decision was the culmination of work by the forest science community to develop Populus as a model system. Since its public release in late 2006, the availability of the Populus genome has spawned research in plant biology, morphology, genetics and ecology. Here we address how the tree physiologist has used this resource. More specifically, we revisit our earlier contention that the rewards of sequencing the Populus genome would depend on how quickly scientists working with woody perennials could adopt molecular approaches to investigate the mechanistic underpinnings of basic physiological processes. Several examples illustrate the integration of functional and comparative genomics into the forest sciences, especially in areas that target improved understanding of the developmental differences between woody perennials and herbaceous annuals (e.g., phase transitions). Sequencing the Populus genome and the availability of genetic and genomic resources has also been instrumental in identifying candidate genes that underlie physiological and morphological traits of interest. Genome-enabled research has advanced our understanding of how phenotype and genotype are related and provided insights into the genetic mechanisms whereby woody perennials adapt to environmental stress. In the future, we anticipate that low-cost, high-throughput sequencing will continue to facilitate research in tree physiology and enhance our understanding at scales of individual organisms and populations. A challenge remains, however, as to how genomic resources, including the Populus genome, can be used to understand ecosystem function. Although examples are limited, progress in this area is encouraging and will undoubtedly improve as future research targets the many unique aspects of Populus as a keystone species in terrestrial ecosystems. PMID:23100257

Wullschleger, Stan D; Weston, D J; DiFazio, S P; Tuskan, G A

2013-04-01

323

Effective-Medium Models for Marine Gas Hydrates, Mallik Revisited  

NASA Astrophysics Data System (ADS)

Hertz-Mindlin type effective-medium dry-rock elastic models have been commonly used for more than three decades in rock physics analysis, and recently have been applied to assessment of marine gas hydrate resources. Comparisons of several effective-medium models with derivative well-log data from the Mackenzie River Valley, Northwest Territories, Canada (i.e. Mallik 2L-38 and 5L-38) were made several years ago as part of a marine gas hydrate joint industry project in the Gulf of Mexico. The matrix/grain supporting model (one of the five models compared) was clearly a better representation of the Mallik data than the other four models (2 cemented sand models; a pore-filling model; and an inclusion model). Even though the matrix/grain supporting model was clearly better, reservations were noted that the compressional velocity of the model was higher than the compressional velocity measured via the sonic logs, and that the shear velocities showed an even greater discrepancy. Over more than thirty years, variations of Hertz-Mindlin type effective medium models have evolved for unconsolidated sediments and here, we briefly review their development. In the past few years, the perfectly smooth grain version of the Hertz-Mindlin type effective-medium model has been favored over the infinitely rough grain version compared in the Gulf of Mexico study. We revisit the data from the Mallik wells to review assertions that effective-medium models with perfectly smooth grains are a better predictor than models with infinitely rough grains. We briefly review three Hertz-Mindlin type effective-medium models, and standardize nomenclature and notation. To calibrate the extended effective-medium model in gas hydrates, we use a well accepted framework for unconsolidated sediments through Hashin-Shtrikman bounds. We implement the previously discussed effective-medium models for saturated sediments with gas hydrates and compute theoretical curves of seismic velocities versus gas hydrate saturation to compare with well log data available from the Canadian gas hydrates research site. By directly comparing the infinitely rough and perfectly smooth grain versions of the Hertz-Mindlin type effective-medium model, we provide additional insight to the discrepancies noted in the Gulf of Mexico study.

Terry, D. A.; Knapp, C. C.; Knapp, J. H.

2011-12-01

324

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

325

Revisiting Scaling Relations for Giant Radio Halos in Galaxy Clusters  

NASA Astrophysics Data System (ADS)

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 500 as P_{1.4} \\sim L^{2.1+/- 0.2}_{500}. Our bigger and more homogenous sample confirms that the X-ray luminous (L 500 > 5 × 1044 erg s-1) 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 1.4 scales with the cluster integrated SZ signal within R 500, measured by Planck, as P_{1.4}\\sim 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 500 > 6 × 10-5 Mpc2 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, M.

2013-11-01

326

Mountain Wave-Induced Turbulence - "Lower Turbulent Zones" Revisited  

NASA Astrophysics Data System (ADS)

In their seminal 1974 paper on "Lower Turbulent Zones Associated with Mountain Lee Waves" P. F. Lester and W. A. Fingerhut attempted to characterize regions of low-level turbulence in the lee of mountain ranges that are commonly associated with large-amplitude mountain waves aloft. For their study, they made extensive use of airborne measurements with small research aircraft that penetrated into the "lower turbulent zone" (LTZ). The Lester and Fingerhut study complemented previous work on wave-induced LTZs by J. P. Kuettner and others in the 1950s who were among the first to employ sailplanes as scientific measurement platforms. Given the limitations of scientific instrumentation on research aircraft in the 1970s (e.g., no GPS) and, in particular, on sailplanes in the 1950s, credit has to be given to these authors for their remarkably detailed account and classification of LTZs. Ever since then, scientists have been trying to refine the conceptual model of the LTZ and shed more light on the origin of turbulence therein. The Terrain-Induced Rotor Experiment (T-REX, Sierra Nevada, California, 2006) is the most recent, major effort organized to investigate the characteristics of LTZs by studying the coupled mountain-wave, rotor, and boundary-layer system. During T-REX, comprehensive ground-based and airborne, in situ and remote sensing measurements were collected during 15 Intensive Observation Periods (IOPs). In this study, we make use of the extensive T-REX datasets to revisit the LTZ concept. During T-REX IOPs, the University of Wyoming King Air (UWKA) research aircraft flew straight-and-level legs aligned with the mean wind direction to document the variation of flow and turbulence over and downwind of the Sierra Nevada. In order to characterize the structure and intensity of turbulence within the LTZ, turbulent kinetic energy (TKE) and eddy-dissipation rate (EDR) were computed from UWKA research flights. In contrast to the rough average values of TKE and EDR obtained by Lester and Fingerhut, high-rate measurements by the UWKA allow documentation of the turbulent flow field at unprecedented spatial resolution and accuracy. Using TKE and EDR obtained from UWKA measurements from the T-REX IOPs with strong low-level turbulence, an attempt is made to summarize the T-REX findings on low-level turbulence and place them in the context of the extant conceptual models of the LTZ. Given the rich variety and complexity of mountain-wave cases observed during the campaign, simple conceptual models, while helpful, provide merely rough guidelines for a possible LTZ classification.

Strauss, Lukas; Grubiši?, Vanda; Serafin, Stefano; Mühlgassner, Rita

2014-05-01

327

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

328

REVISITING SCALING RELATIONS FOR GIANT RADIO HALOS IN GALAXY CLUSTERS  

SciTech Connect

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}?L{sup 2.1±0.2}{sub 500}. Our bigger and more homogenous sample confirms that the X-ray luminous (L{sub 500} > 5 × 10{sup 44} erg s{sup –1}) 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}?Y{sup 2.05±0.28}{sub 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{sup –5} Mpc{sup 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.; Brunetti, G.; Venturi, T.; Kale, R. [INAF/IRA, via Gobetti 101, I-40129 Bologna (Italy); Ettori, S. [INAF/Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Giacintucci, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Pratt, G. W. [Laboratoire AIM, IRFU/Service dAstrophysique-CEA/DSM-CNRS-Université Paris Diderot, Bât. 709, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Dolag, K. [University Observatory Munich, Scheinerstr. 1, D-81679 Munich (Germany); Markevitch, M. [Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2013-11-10

329

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

330

Outline Motivation of the study Sublinear eigenvalue problems associated to the Laplace operator revisited Eigenvalue problems for th Nonlinear eigenvalue problems for  

E-print Network

Outline Motivation of the study Sublinear eigenvalue problems associated to the Laplace operator Motivation of the study Sublinear eigenvalue problems associated to the Laplace operator revisited Eigenvalue to the Laplace operator revisited Eigenvalue problems for th Outline of the talk Motivation of the study

331

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

. 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: the aims of education re-visited in the information society: how can ICT help innovation SCIENTER 2

Paris-Sud XI, Université de

332

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.

333

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

334

Memory Organization in MultiChannel Optical Networks: NUMA and COMA Revisited  

E-print Network

Memory Organization in Multi­Channel Optical Networks: NUMA and COMA Revisited YanYang Xiao, and has in particu­ lar favored cache­coherent non­uniform memory access (CC­ NUMA) over cache­only memory in the presence of high bandwidth and scal­ able broadcast. Using simulation, we compare the perfor­ mance of CC­NUMA

Bennett, John K.

335

Revisiting the Controlled teleportation schemes from the controller's point of view  

E-print Network

We present a quantity to evaluate the controller's power in controlled teleportation schemes and give a reasonable lower bound for controlled teleportation protocol of N-qubit state. We revisit several typical controlled teleportation schemes from the controller's point of view. We ?nd for teleporting arbitrary N-qubit states, each controller should master N bits useful information at least to ensure his authority. We also discuss the general rules for eligible controlled teleportation schemes.

Xi-Han Li; Shohini Ghose

2014-10-07

336

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

Microsoft Academic Search

\\u000a We revisit Monte-Carlo Tree Search on a recent game, termed NoGo. Our goal is to check if known results in Computer-Go and\\u000a various other games are general enough for being applied directly on a new game. We also test if the known limitations of\\u000a Monte-Carlo Tree Search also hold in this case and which improvements of Monte-Carlo Tree Search are

C.-W. Chou; Olivier Teytaud; Shi-Jim Yen

2011-01-01

337

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

338

Volume 62A, number 4 PHYSICS LETTERS 22 August 1977 THE ZEEMAN EFFECT REVISITED  

E-print Network

].Someoftheresultsextendto q =11n2+4C+ ~ ~÷ r e_X --1 dx~00S796, more general atoms and we have studied the correc- 0 1 xVolume 62A, number 4 PHYSICS LETTERS 22 August 1977 THE ZEEMAN EFFECT REVISITED J. AVRON~and I of the field. The weak field Zeeman effect [1] in simple atoms A = -4(r X B); B = (0,0, B) (2) was one

Makarov, Nikolai

339

The Reachability Problem for Uncertain Hybrid Systems Revisited: A Viability Theory Perspective  

Microsoft Academic Search

\\u000a We revisit the problem of designing controllers to meet safety specifications for hybrid systems, whose evolution is affected\\u000a by both control and disturbance inputs. The problem is formulated as a dynamic game and an appropriate notion of hybrid strategy\\u000a for the control inputs is developed. The design of hybrid strategies to meet safety specifications is based on an iteration\\u000a of

Yan Gao; John Lygeros; Marc Quincampoix

2006-01-01

340

The Msissi norite revisited - K/Ar dating, petrography and paleomagnetism  

NASA Astrophysics Data System (ADS)

The 'Msissi norite' in Morocco (30.93 deg N, 4.71 deg W), from where one of the paleomagnetic reference pole for Africa in Devonian times has been derived, has been revisited and dated. Petrological examination shows that the rock is an alkaline gabbro (teschenite). K-Ar analyses on fresh biotite yield a 136-139 Ma age, which infirms the supposed Devonian age. The paleomagnetic study displays several distinct magnetic components.

Salmon, E.; Montigny, R.; Edel, J. B.; Pique, A.; Thuizat, R.

1986-08-01

341

Optimum concentration of trifluoroacetic acid for reversed-phase liquid chromatography of peptides revisited  

Microsoft Academic Search

Trifluoroacetic acid (TFA) remains the dominant mobile phase additive for reversed-phase high-performance liquid chromatography (RP-HPLC) of peptides after more than two decades since its introduction to this field. Generally, TFA has been employed in a concentration range of 0.05–0.1% (6.5–13mM) for the majority of peptide separations. In order to revisit the question as to whether such a concentration range is

Y Chen; A. R Mehok; C. T Mant; R. S Hodges

2004-01-01

342

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

343

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

344

RNS derivation of N-point disk amplitudes from the revisited S-matrix approach  

E-print Network

In the past year, in arXiv:1208.6066 we proposed a revisited S-matrix approach to efficiently find the bosonic terms of the open superstring low energy effective lagrangian (OSLEEL). This approach allows to compute the ${\\alpha'}^N$ terms of the OSLEEL using open superstring $n$-point amplitudes in which $n$ is very much lower than $(N+2)$ (which is the order of the required amplitude to obtain those ${\\alpha'}^N$ terms by means of the conventional S-matrix approach). In this work we use our revisited S-matrix approach to examine the structure of the scattering amplitudes, arriving at a closed form for them. This is a RNS derivation of the formula first found by Mafra, Schlotterer and Stieberger in arXiv:1106.2645, using the Pure Spinor formalism. We have succeeded doing this for the 5, 6 and 7-point amplitudes. In order to achieve these results we have done a careful analysis of the kinematical structure of the amplitudes, finding as a by-product a purely kinematical derivation of the BCJ relations (for N=4, 5, 6 and 7). Also, following the spirit of the revisited S-matrix approach, we have found the $\\alpha'$ expansions for these amplitudes up to ${\\alpha'}^6$ order in some cases, by only using the well known open superstring 4-point amplitude, cyclic symmetry and tree level unitarity: we have not needed to compute any numerical series or any integral involving polylogarithms, at any moment.

Luiz Antonio Barreiro; Ricardo Medina

2013-10-22

345

Revisit Behavior in Social Media: The Phoenix-R Model and Discoveries  

E-print Network

How many listens will an artist receive on a online radio? How about plays on a YouTube video? How many of these visits are new or returning users? Modeling and mining popularity dynamics of social activity has important implications for researchers, content creators and providers. We here investigate and model the effect of revisits on popularity. A revisit can be defined as a repeated play (song or video) or a re-tweet of the same hashtag over time. Using four datasets of social activity, with up to tens of millions media objects (e.g., YouTube videos, Twitter hashtags or LastFM artists), we show the effect of revisits in the popularity evolution of such objects. Secondly, we propose the Phoenix-R model which captures the popularity dynamics of individual objects. Phoenix-R has the desired properties of being: (1) parsimonious, being based on the minimum description length principle, and achieving lower root mean squared error than state-of-the-art baselines; (2) applicable, the model is effective for predi...

Figueiredo, Flavio; Matsubara, Yasuko; Ribeiro, Bruno; Faloutsos, Christos

2014-01-01

346

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

347

Revisiting the Saffman-Taylor experiment: imbibition patterns and liquid-entrainment transitions.  

PubMed

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. PMID:25105621

Levaché, Bertrand; Bartolo, Denis

2014-07-25

348

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

349

Global dynamics of Nicholson?s blowflies equation revisited: Onset and termination of nonlinear oscillations  

NASA Astrophysics Data System (ADS)

We revisit Nicholson's blowflies model with natural death rate incorporated into the delay feedback. We consider the delay as a bifurcation parameter and examine the onset and termination of Hopf bifurcations of periodic solutions from a positive equilibrium. We show that the model has only a finite number of Hopf bifurcation values and we describe how branches of Hopf bifurcations are paired so the existence of periodic solutions with specific oscillation frequencies occurs only in bounded delay intervals. The bifurcation analysis and the Matlab package DDE-BIFTOOL developed by Engelborghs et al. guide some numerical simulations to identify ranges of parameters for coexisting multiple attractive periodic solutions.

Shu, Hongying; Wang, Lin; Wu, Jianhong

350

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 Belen; Andrade, Raquel Tapajos; Tauil, Pedro Luiz; Monteiro, Wuelton Marcelo; Lacerda, Marcus Vinicius Guimaraes

2014-01-01

351

Theoretical revisit of a Fe(CO)(5)-catalyzed water-gas shift reaction.  

PubMed

We have revisited the water-gas shift reaction catalyzed by iron pentacarbonyl at the DFT-B3LYP level. The reaction mechanism proposed by Rozanska and Vuilleumier (Inorg. Chem. 2008, 47, 8635-8640) has been followed and revised. The results show that transition states TS4/5 and TS5/2_a actually connect other intermediates rather than those suggested by Rozanska and Vuilleumier. Furthermore, the entire reaction has been proven to proceed with processes 1 --> 2 --> 3 --> 4 --> 6 --> 7 --> 2. It is the first time that species 6 and 7 are reported as intermediates for this reaction mechanism. PMID:20199050

Zhang, Fuli; Zhao, Liang; Xu, Chunming; Chen, Yu

2010-04-01

352

Long, Cold, Early r Process? Neutrino-Induced Nucleosynthesis in He Shells Revisited  

SciTech Connect

We revisit a {nu}-driven r-process mechanism in the He shell of a core-collapse supernova, finding that it could succeed in early stars of metallicity Z < or approx. 10{sup -3}Z{sub {center_dot}}, at relatively low temperatures and neutron densities, producing A{approx}130 and 195 abundance peaks over {approx}10-20 s. The mechanism is sensitive to the {nu} emission model and to {nu} 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.

Banerjee, Projjwal; Qian Yongzhong [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Haxton, W. C. [Department of Physics, University of California, and Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2011-05-20

353

Revisiting Du Bois: The Relationship Between African American Double Consciousness and Beliefs About Racial and National Group Experiences  

Microsoft Academic Search

This study revisits Du Bois’s concept of double consciousness by examining the relationship between racial and mainstream acculturation and African Americans’ beliefs about their racial and national groups. Surveys completed by 100 prospective Black jurors at a municipal courthouse approximately 6 months after 9\\/11 revealed that they perceived their racial group as more unjustly treated and more helpless than their

Mikhail Lyubansky; Roy J. Eidelson

2005-01-01

354

Revisiting silicon budgets at a tropical continental shelf: Silica standing stocks in sponges surpass those in diatoms  

E-print Network

Revisiting silicon budgets at a tropical continental shelf: Silica standing stocks in sponges in five habitats of an extensive continental shelf area of the Mesoamerican Caribbean. In most habitats-ocean blue water, it may not realistically reflect the situation on at least some continental shelves, which

Maldonado, Manuel

355

Revisiting Risk in the 21st Century. Forum Focus. Volume 3, Issue 1, January-February 2005  

ERIC Educational Resources Information Center

Over the past year, dozens of articles have been published about excessive youth borrowing and spending (leading to high amounts of debt), new reactions to negative body image (such as plastic surgery), as well as more familiar risks like premarital sex and smoking. In Forum Focus: Revisiting Risk in the 21st Century, we explore these challenges…

Forum for Youth Investment, 2005

2005-01-01

356

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

357

Today's Teens, Their Problems, and Their Literature: Revisiting G. Robert Carlsen's "Books and the Teenage Reader" Thirty Years Later.  

ERIC Educational Resources Information Center

Revisits G. Robert Carlsen's call for the use of young adult literature in the classroom by looking specifically at the emotional and reading needs of older adolescents, those in the upper grades. Discusses problems associated with adolescence in the late twentieth century and lists recommended young adult books that touch on those issues. (TB)

Carroll, Pamela Sissi

1997-01-01

358

Asymmetric copper-catalyzed Diels-Alder reaction revisited: control of the structure of bis(oxazoline) ligands.  

E-print Network

1 Asymmetric copper-catalyzed Diels-Alder reaction revisited: control of the structure of bis,R)-dihydroethano trans-dicarboxylic acid, a complete series of ligands was evaluated in the copper-catalyzed Diels-Alder[2.2.2] backbone; Diels-Alder catalysis; Copper; Enantioselectivity. * Corresponding author. E

Paris-Sud XI, Université de

359

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

360

32ND INTERNATIONAL COSMIC RAY CONFERENCE, BEIJING 2011 Heliocentric Distance of CMEs at the Time of Energetic Particle Release: Revisit-  

E-print Network

of Energetic Particle Release: Revisit- ing the Ground Level Enhancement Events of Solar Cycle 23 NAT of the energetic particles during the ground level enhancement (GLE) events of Solar Cycle 23. We find that the GLE particles are released when the CMEs reach an average heliocentric distance of ~3.6 solar radii (Rs

Usoskin, Ilya G.

361

PROCEEDINGS of the Third International Driving Symposium on Human Factors in Driver Assessment, Training and Vehicle Design STEERING ENTROPY REVISITED  

E-print Network

. Steering entropy was introduced to quantify drivers' efforts to maintain their lateral safety margins frequencies and an increased number of safety margin violations. Steering entropy (SE) was developed, Training and Vehicle Design 25 STEERING ENTROPY REVISITED Erwin R. Boer LUEBEC San Diego, California, USA E

Goodrich, Michael A.

362

Abstract--In the context of the ongoing deregulation of the electricity industry, we revisit the commonly held assumption that,  

E-print Network

1 Abstract-- In the context of the ongoing deregulation of the electricity industry, we revisit, Power generation dispatch, Power generation economics I. INTRODUCTION n the deregulated industry. Tasks that were performed in a centralized, coordinated fashion, are now performed by market

Ilic, Marija D.

363

The fit between capabilities and priorities and its impact on performance improvement: revisiting and extending the theory of production competence  

Microsoft Academic Search

This paper revisits and extends the theory of production competence, which has received wide attention in the operations and production management literature. As such, considering the aspects of quality, delivery, flexibility, and cost, we develop two novel measures that assess the concept of production competence, which is conceptualised as the fit between production and operations management (POM) capabilities and production

Tobias Schoenherr; Ram Narasimhan

2012-01-01

364

The fit between capabilities and priorities and its impact on performance improvement: revisiting and extending the theory of production competence  

Microsoft Academic Search

This paper revisits and extends the theory of production competence, which has received wide attention in the operations and production management literature. As such, considering the aspects of quality, delivery, flexibility, and cost, we develop two novel measures that assess the concept of production competence, which is conceptualised as the fit between production and operations management (POM) capabilities and production

Tobias Schoenherr; Ram Narasimhan

2011-01-01

365

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

366

Revisiting the mechanisms of metformin action in the liver Les mcanismes d'action de la metformine dans le foierevisits  

E-print Network

Revisiting the mechanisms of metformin action in the liver Les mécanismes d'action de la metformine of metformin, the first line therapeutic for type 2 diabetes, its mechanisms of action has not been fully molecular mechanism of action now emerges from recent breakthroughs that place metformin at the control

Paris-Sud XI, Université de

367

Int. J. Human-Computer Studies 69 (2011) 170181 Revisiting path steering for 3D manipulation tasks  

E-print Network

Int. J. Human-Computer Studies 69 (2011) 170­181 Revisiting path steering for 3D manipulation tasks of path steering, as proposed by Accot and Zhai, describes a quantitative relationship between the human temporal performance and the path spatial characteristics. The steering law is formulated as a continuous

Liere, Robert van

368

steiner@kis.uni-freiburg.de http://www.kis.uni-freiburg.de/~steiner Multi-Grid Radiation Transfer Revisited  

E-print Network

steiner@kis.uni-freiburg.de http://www.kis.uni-freiburg.de/~steiner Multi-Grid Radiation Transfer Revisited Kiepenheuer-Institut fuer Sonnenphysik, FreiburgOskar Steiner Homogeneous slab Figure 2 shows for this problem of the accelerated - iteration (·) with the multi-grid method (). The two scales account for a W

Steiner, Oskar

369

Revisiting an Old Friend: The Practice and Promise of Cooperative Learning for the Twenty-First Century  

ERIC Educational Resources Information Center

Cooperative learning has long been at the disposal of school teachers. However, it is often misunderstood by some teachers as just another form of collaborative group work. This article revisits cooperative learning, including a sampling of its popular variations, with practical approaches toward effectively integrating it into classroom…

Schul, James E.

2011-01-01

370

From Revisiting the LCA-based Approach to a New Semantics-based Approach for XML Keyword Search  

E-print Network

From Revisiting the LCA-based Approach to a New Semantics-based Approach for XML Keyword Search keyword search approach, and propose an approach to perform XML keyword search based on semantics rather search has been studied for several years. Inspired by the hierarchical structure of XML data, most

Ling, Tok Wang

371

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

372

A resource based interpretation of performance enhancing capital structure changes: The O.M. Scott LBO revisited  

E-print Network

.M. Scott LBO revisited Peter Wirtz Université Lumière (Lyon 2) Abstract The O.M. Scott case study published in 1989 in the Journal of Financial Economics has come to be a classic in illustrating the plausibility-LBO was to a great extent the consequence of the yet unexplored cognitive changes implied by switching dominant

Boyer, Edmond

373

Revisiting "Kindergarten as Academic Boot Camp": A Nationwide Study of Ability Grouping and Psycho-Social Development  

ERIC Educational Resources Information Center

We revisit Harry L. Gracey's perspective of kindergarten as academic boot camp where, at school entry, children acquire the student role through a structured program of activities. We provide further insights into the crucial mechanisms of socialization that occur in U.S. kindergartens by examining the relationship between within-class ability…

Catsambis, Sophia; Buttaro, Anthony, Jr.

2012-01-01

374

SN1987A: Revisiting the Data and the Correlation between Neutrino and Gravitational Detectors  

E-print Network

We re-examine the data taken by the neutrino detectors during the supernova SN1987A. It is found that the Kamiokande data, in addition to the well known burst at 7:35 hours UT, show another one at 7:54 hours, with seven pulses in 6.2 seconds. This second burst supports the idea that the duration of the collapse was much longer than a few seconds, as already suggested by the LSD detection at 2:56 hours the same day, i.e. four and a half hours earlier. The correlations between the gravitational wave detectors (Rome and Maryland) and the neutrino detectors are also revisited. It is shown that the g.w. detectors exhibit significant correlations with both the LSD and the Kamiokande detectors over periods of one-two hours that are centered, in both cases, at the LSD time.

P. Galeotti; G. V. Pallottino; G. Pizzella

2008-10-21

375

Sn1987a Revisited after 20 Years: May the Supernova Bang More Than Once?  

E-print Network

The observations of supernova 1987A in underground detectors are revisited. It is shown that, while the LSD detector in the Mont Blanc Laboratory observed only one burst at 2h 52min 36.8sec U.T., the Kamiokande data show a possible second burst, in addition to the well known one at 7h 35min 33.7sec U.T. This second burst consists of a cluster of seven pulses, well above the energy threshold of the detector, observed during 6.2 seconds starting at 7h 54min 22.2sec U.T. Do these observations imply a long duration of the collapse?

P. Galeotti; G. Pizzella

2007-06-15

376

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

377

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

378

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

379

The impact of minimum legal drinking age laws on alcohol consumption, smoking, and marijuana use revisited.  

PubMed

In volume 30, issue 4 of this journal, we used data from the National Longitudinal Study of Youth, 1997 cohort (NLSY97) to estimate the impact of the minimum legal drinking age (MLDA) laws on alcohol consumption, smoking, and marijuana use among young adults. In our analysis, we used a restricted sample of young adults and considered only those who have consumed alcohol, smoked cigarettes, or used marijuana at least once since the date of their last interview. In this paper, we revisit our original study using the full sample. We show that our results for alcohol consumption in the full sample are similar to those from the restricted sample. However, the effect of the MLDA on smoking and marijuana use is smaller and often statistically insignificant. PMID:23092933

Yörük, Bar?? K; Yörük, Ceren Ertan

2013-03-01

380

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

381

Revisiting the death of Eleanor Roosevelt: was the diagnosis of tuberculosis missed?  

PubMed

Controversy has surrounded the death of Eleanor Roosevelt in 1962. There has been a persistent sense that doctors missed the diagnosis of miliary tuberculosis, thereby jeopardizing her life. This article, using Roosevelt's medical chart and other previously unreviewed documents, revisits her illness and death. What disease actually killed Eleanor Roosevelt? Did her physicians miss the diagnosis? These questions are of particular importance in light of the recent Institute of Medicine report estimating that almost 100,000 Americans die each year from medical mistakes. Why has the possibility of error clouded the care of Roosevelt for almost 40 years? What can Roosevelt's case reveal about ongoing efforts to reduce mistakes in clinical practice? PMID:11769765

Lerner, B H

2001-12-01

382

On the origin of damped electrochemical oscillations at silicon anodes (revisited).  

PubMed

Electrochemical oscillations accompanying the formation of anodic silica have been shown in the past to be correlated with rather abrupt changes in the mechanical stress state of the silica film, commonly associated with some kind of fracture or porosification of the oxide. To advance the understanding on the origin of such oscillations in fluoride-free electrolytes, we have revisited a seminal experiment reported by Lehmann almost two decades ago. We thereby demonstrate that the oscillations are not stress-induced, and do not originate from a morphological transformation of the oxide in the course of anodisation. Alternatively, the mechanical features accompanying the oscillations can be explained by a partial relaxation of the field-induced electrostrictive stress. Furthermore, our observations suggest that the oscillation mechanism more likely results from a periodic depolarisation of the anodic silica. PMID:25164094

Proost, Joris; Blaffart, Frédéric; Turner, Stuart; Idrissi, Hosni

2014-10-01

383

Revisiting scope of practice facilitators and barriers for primary care nurse practitioners: a qualitative investigation.  

PubMed

Revisiting scope of practice (SOP) policies for nurse practitioners (NPs) is necessary in the evolving primary care environment with goals to provide timely access, improve quality, and contain cost. This study utilized qualitative descriptive design to investigate NP roles and responsibilities as primary care providers (PCPs) in Massachusetts and their perceptions about barriers and facilitators to their SOP. Through purposive sampling, 23 NPs were recruited and they participated in group and individual interviews in spring 2011.The interviews were audio recorded and transcribed. Data were analyzed using Atlas.ti 6.0 software, and content analysis was applied. In addition to NP roles and responsibilities, three themes affecting NP SOP were: regulatory environment; comprehension of NP role; and work environment. NPs take on similar responsibilities as physicians to deliver primary care services; however, the regulatory environment and billing practices, lack of comprehension of the NP role, and challenging work environments limit successful NP practice. PMID:23528433

Poghosyan, Lusine; Nannini, Angela; Smaldone, Arlene; Clarke, Sean; O'Rourke, Nancy C; Rosato, Barbara G; Berkowitz, Bobbie

2013-02-01

384

What drives health care expenditure?--Baumol's model of 'unbalanced growth' revisited.  

PubMed

The share of health care expenditure in GDP rises rapidly in virtually all OECD countries, causing increasing concern among politicians and the general public. Yet, economists have to date failed to reach an agreement on what the main determinants of this development are. This paper revisits Baumol's [Baumol, W.J., 1967. Macroeconomics of unbalanced growth: the anatomy of urban crisis. American Economic Review 57 (3), 415-426] model of 'unbalanced growth', showing that the latter offers a ready explanation for the observed inexorable rise in health care expenditure. The main implication of Baumol's model in this context is that health care expenditure is driven by wage increases in excess of productivity growth. This hypothesis is tested empirically using data from a panel of 19 OECD countries. Our tests yield robust evidence in favor of Baumol's theory. PMID:18164773

Hartwig, Jochen

2008-05-01

385

Revisiting Down syndrome from the ENT perspective: review of literature and recommendations.  

PubMed

Down syndrome is the most common chromosomal abnormality among live born infants reaching up to 1 in 700 births and is characterized by a variety of dysmorphic features and medical conditions. The potential to reach their full developmental capacities can be hindered by ear, nose, and throat problems. Hence, knowledge of the various anatomic peculiarities that predispose them to various medical conditions is fundamental. The medical states resulting from these variations and suggested treatment options are reviewed. Such conditions include refractory otitis, eustachian tube dysfunction, laryngomalacia, tracheal stenosis, obstructive sleep apnea, hearing loss, and voice and articulatory impairments. This review revisits besides the otolaryngeal pathologies, special medical considerations in Down's syndrome patients that might affect surgical outcomes used in the management of the above pathologies. PMID:23689804

Ramia, Maria; Musharrafieh, Umayya; Khaddage, Wajdi; Sabri, Alain

2014-05-01

386

Revisiting the universality of (multiple) star formation in present-day star formation regions  

E-print Network

Populations of multiple stars inside clustered regions are known to change through dynamical interactions. The efficiency of binary disruption is thought to be determined by stellar density. King and collaborators recently investigated the multiplicity properties in young star forming regions and in the Galactic field. They concluded that stellar density-dependent modification of a universal initial binary population (the standard or null hypothesis model) cannot explain the observations. We re-visit their results, analyzing the data within the framework of different model assumptions, namely non-universality without dynamical modification and universality with dynamics. We illustrate that the standard model does account for all known populations if regions were significantly denser in the past. Some of the effects of using present-day cluster properties as proxies for their past values are emphasized and that the degeneracy between age and density of a star forming region can not be omitted when interpreting...

Marks, Michael; Giersz, Mirek; Pfalzner, Susanne; Pflamm-Altenburg, Jan; Oh, Seungkyung

2014-01-01

387

Multinational Knowledge Strategies, Policy and the Upgrading Process of Regions: Revisiting the Automotive Industry in Ostrava and Shanghai  

Microsoft Academic Search

This paper revisits how and why new multinational knowledge-based strategies and multi-level governmental policies influence the upgrading process of regions in developing economies. Automotive multinationals traditionally exploited local asset conditions, but it is shown that they have also been contributing to knowledge-generation systems via investments in R&D centres and cooperation with regional knowledge producers. We discern three elements of the

Erwin van Tuijl; Luis Carvalho; Willem Van Winden; Wouter Jacobs

2012-01-01

388

Decision-making in the physician–patient encounter: revisiting the shared treatment decision-making model  

Microsoft Academic Search

In this paper we revisit and add elements to our earlier conceptual framework on shared treatment decision-making within the context of different decision-making approaches in the medical encounter (Charles, C., Gafni, A., Whelan, T., 1997. Shared decision-making in the medical encounter: what does it mean? (or, it takes at least two to tango). Social Science & Medicine 44, 681–692.). This

Cathy Charles; Amiram Gafni; Tim Whelan

1999-01-01

389

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

390

Revisiting the Stimulus-Secretion Coupling in the Adrenal Medulla: Role of Gap Junction-Mediated Intercellular Communication  

Microsoft Academic Search

The current view of stimulation-secretion coupling in adrenal neuroendocrine chromaffin cells holds that catecholamines are\\u000a released upon transsynaptic sympathetic stimulation mediated by acetylcholine released from the splanchnic nerve terminals.\\u000a However, this traditional vertical scheme would merit to be revisited in the light of recent data. Although electrical discharges\\u000a invading the splanchnic nerve endings are the major physiological stimulus to trigger

Claude Colomer; Michel G. Desarménien; Nathalie C. Guérineau

2009-01-01

391

Understanding and Revisiting Properties of EuTiO3 Bulk Material and Films from First Principles  

NASA Astrophysics Data System (ADS)

Ab initio computations are performed to investigate properties of bulk material and epitaxial films made of EuTiO3 (ETO). A whole family of nanoscale twinned phases, that present complex oxygen octahedra tilting (OOT) and unusual antiferroelectricity, is found to be degenerate in energy with simpler phases (all possessing typical OOT) in bulk ETO. Such degeneracy provides a successful explanation of recently observed anomalous phenomena. The calculations also lead to revisiting the (rich) phase diagram of ETO films.

Yang, Yurong; Ren, Wei; Wang, Dawei; Bellaiche, L.

2012-12-01

392

Understanding and revisiting properties of EuTiO3 bulk material and films from first principles.  

PubMed

Ab initio computations are performed to investigate properties of bulk material and epitaxial films made of EuTiO3 (ETO). A whole family of nanoscale twinned phases, that present complex oxygen octahedra tilting (OOT) and unusual antiferroelectricity, is found to be degenerate in energy with simpler phases (all possessing typical OOT) in bulk ETO. Such degeneracy provides a successful explanation of recently observed anomalous phenomena. The calculations also lead to revisiting the (rich) phase diagram of ETO films. PMID:23368621

Yang, Yurong; Ren, Wei; Wang, Dawei; Bellaiche, L

2012-12-28

393

PRELIMINARY REPORT In Vivo Visualization of White Matter Fiber Tracts of  

E-print Network

, the inferior fronto- occipital fasciculi, and optic radiations were visualized. Results: Our results suggest tractography (or "WM fiber tracking") techniques have been developed to establish interregional connectivity for resolving their smaller ana- tomic structures. In addition, the developing infant brain possesses vastly

394

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

Microsoft Academic Search

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 throughout the childhood years, and several lines of evidence implicate the left fronto-parietal cortices and connecting fiber tracts

Martin Vestergaard; Kathrine Skak Madsen; William F. C. Baaré; Arnold Skimminge; Lisser Rye Ejersbo; Thomas Z. Ramsøy; Christian Gerlach; Per Åkeson; Olaf B. Paulson; Terry L. Jernigan

2011-01-01

395

Diffusion tensor spectroscopy and imaging of the arcuate fasciculus Jaymin Upadhyay,a,b  

E-print Network

characterization of AF is possible. In this study, water-based diffusion tensor probabilistic mapping was first on the diffusion of water, which is not particular to either the intra- or extra-axonal compartments, and thus its. Diffusion properties of NAA, which solely reflect the intra-axonal space, indicated possible leftward

Reber, Paul J.

396

White Matter Differences in the Inferior Longitudinal Fasciculus Between First Episode and Chronic Schizophrenia Patients  

E-print Network

of treatment and/or a progression of the disease. Tractography Results of the ILFAnterior and Posterior ROI), Michael J. Lyons (5), Marek Kubicki(1, 4), Martha E. Shenton (1, 4) (1) Psychiatry Neuroimaging Laboratory

397

Differences in the right inferior longitudinal fasciculus but no general disruption of white matter tracts in  

E-print Network

,e , and Nancy Kanwishera,1 a Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology for review December 8, 2013) One of the most widely cited features of the neural phenotype of autism of white matter tracts in autism, instead implicating only one tract, the right ILF, in the ASD phenotype

Kanwisher, Nancy

398

Bryonora, Praha, 34 (2004) 41 Vzda A. (2003): Lichenes rariores exsiccati. Fasciculus 4950 (numeris 481500). Brno.  

E-print Network

among Central European species of the aquatic moss Cinclidotus. ­ Cryptogamie Bryologie 24: 147. ­ Journal of Molecular Evolution 55: 595­605. Aldous A. R. (2002): Nitrogen translocation in Sphagnum mosses (2004) Allen B. (ed.) (2002): Moss flora of Central America. Part 2. Encalyptaceae

Kucera, Jan

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

Robbins Revisited.  

ERIC Educational Resources Information Center

The Robbins Report of 1966, which has influenced the development of higher education in Great Britain for many years, now seems dated. Changed national economic conditions and changed ideological emphasis (now more utilitarian, more humane, and less elitist) have caused a divergence in British higher education in recent years. (MSE)

Niblett, W. Roy

1981-01-01

401

Lipoatrophy Revisited  

Microsoft Academic Search

The lipoatrophy syndromes are a heterogeneous group of syndromes characterized by a paucity of adipose tissue. Severe lipoatrophy is associated with insulin-resistant diabetes mellitus (DM). The loss of adipose tissue can have a genetic, immune, or infectious\\/drug-associated etiology. Causative mutations have been identified in patients for one form of partial lipoatrophy – Dunnigan-type familial partial lipodystrophy. Experiments using lipoatrophic mice

Marc L. Reitman; Elif Arioglu; Oksana Gavrilova; Simeon I. Taylor

2000-01-01

402

Hybridomas revisited.  

PubMed

In the report by John C. Behrendt et al. "Aeromagnetic and radio echo ice-sounding measurements show much greater area of the Dufek Intrusion, Antarctica" (29 Aug., p. 1014), the word "expedition" should have read "exploitation" in line 13 of the first paragraph on page 1014. Also, in line 2 of the next to last paragraph on page 1016, "50 to 60 cm/sec(2)" should have read "50 to 60 (cm sec(2)) x 10(-3)." PMID:7423184

Koprowski, H; Croce, C

1980-10-17

403

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

404

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

405

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

406

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

407

Censorship Revisited.  

ERIC Educational Resources Information Center

Governments, groups, and individuals have always tried to control information. This paper examines censorship, particularly textbook censorship and its effect upon the curriculum, and opposes the recent trend to censor textbooks in public schools. Since the mission of public schooling involves indoctrination and socialization as much as education,…

Fernandez, Melanie

408

Youngstown Revisited  

Microsoft Academic Search

In 1952, President Harry S. Truman promulgated an Executive Order that authorized federal government seizure of the nation's steel mills to support United States participation in the Korean conflict, but the Supreme Court held that Truman lacked any power to seize the property in Youngstown Sheet & Tube Co. v. Sawyer. In 2001, President George W. Bush promulgated an Executive

A. Christopher Bryant; Carl Tobias

2002-01-01

409

Bibliophilately Revisited.  

ERIC Educational Resources Information Center

Discusses stamps and other postal products that feature libraries and/or librarians. Offers advice for creating a postal memento for individual libraries and how to lobby for library-related stamps. (LRW)

Nix, Larry T.

2000-01-01

410

Power, Revisited  

ERIC Educational Resources Information Center

Power is a core theoretical construct in the field with amazing utility across substantive areas, levels of analysis and methodologies. Yet, its use along with associated assumptions--assumptions surrounding constraint vs. action and specifically organizational structure and rationality--remain problematic. In this article, and following an…

Roscigno, Vincent J.

2011-01-01

411

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

412

Phenytoin revisited.  

PubMed

Phenytoin has a wide range of pharmacologic effects other than its anticonvulsant activity. It has been the subject of more than 8,000 published papers, which include clinical reports of its usefulness in approximately 100 diseases and symptoms. In the United States the only indications for use in the official labeling for phenytoin are various types of seizures. An advisory committee of the Food and Drug Administration recently recommended the addition of certain cardiac arrhythmias to the labeling. To determine whether other uses should be added to the labeling and whether additional clinical trials should be encouraged, an in-depth review of the published literature was undertaken. This review revealed that, on the basis of controlled studies, phenytoin is probably useful in the continuous muscle fiber activity syndrome, myotonic muscular dystrophy, and myotonia congenita. In addition, phenytoin appears to be potentially useful in recessive dystrophic epidermolysis bullosa, intermittent explosive disorder, anxiety disorder in which anger and irritability are prominent features, and, topically, in burns and refractory skin ulcers. Additional clinical studies are needed before definitive conclusions can be drawn. Clinical trials of phenytoin in most of these disorders are ongoing or are contemplated. Any labeling changes will await results of the studies. Based on phenytoin's pharmacologic effects in animals, controlled trials of the drug appear to be warranted in cerebral ischemia and stroke, spinal cord injury, angina pectoris, and fractures in which the rate of healing is poor. PMID:6383610

Finkel, M J

1984-01-01

413

Pneumomediastinum revisited.  

PubMed

Pneumomediastinum may result from a variety of causes that may be either intrathoracic (eg, narrowed or plugged airway, straining against a closed glottis, blunt chest trauma, alveolar rupture) or extrathoracic (eg, sinus fracture, iatrogenic manipulation in dental extraction, perforation of a hollow viscus [corrected]. The radiographic signs of pneumomediastinum depend on the depiction of normal anatomic structures that are outlined by the air as it leaves the mediastinum. These signs include the thymic sail sign, "ring around the artery" sign, tubular artery sign, double bronchial wall sign, continuous diaphragm sign, and extrapleural sign. In distal esophageal rupture, air may migrate from the mediastinum into the pulmonary ligament. Pneumomediastinum may be difficult to differentiate from medial pneumothorax and pneumopericardium. Occasionally, normal anatomic structures (eg, major fissure, anterior junction line) may simulate air within the mediastinum. Iatrogenic entities that may simulate pneumomediastinum include helium in the balloon of an intraaortic assist device. In addition, pneumomediastinum may be simulated by the Mach band effect, which manifests as a region of lucency adjacent to structures with convex borders. The absence of an opaque line, which is typically seen in pneumomediastinum, can aid in differentiation. Computed tomographic (CT) digital radiography and conventional CT can also be helpful in establishing or confirming the diagnosis. PMID:10903694

Zylak, C M; Standen, J R; Barnes, G R; Zylak, C J

2000-01-01

414

Myolysis Revisited  

PubMed Central

Numerous procedures have been developed in recent decades that claim to provide significant improvement in myoma status without hysterectomy. However, what is the cost in time and money of these procedures? This is a review of the current literature regarding these recent procedures to determine which, if any, is the best treatment for myomas. We conducted a search of PubMed using the terms “bipolar-, cryo-, radiofrequency, laparoscopic-, focused high-energy MRI-guided ultrasound, and MRI-guided laser myolysis” to identify reports of the various procedures. Based on these published reports, we describe the various types of myolysis performed in multiple patients in outpatient facilities including patient outcomes, complications, cost, and efficiency of the procedures. PMID:19275864

2008-01-01

415

Polybenzene revisited.  

PubMed

Polybenzene was described by O'Keeffe et al., as an embedding of a 6.82 net in the infinite periodic minimal D-surface, with a single type of carbon atoms and was predicted to have a substantially lower energy per atom in comparison to C60, the reference structure in Nanoscience. They also described a 6.82 net embedded in the periodic minimal P-surface. We give here a rational structure construction for three benzene-based units (a third one described here for the first time in literature) and the corresponding networks. Their stability, relative to C60 but also to diamonds (the classical diamond D6 and the pentagon-based diamond D5), was calculated at the Hartree-Fock level of theory. The results confirmed the previous stability evaluation and support these structures for laboratory preparation. A Graph-theoretical description, in terms of Omega polynomial, of the three infinite networks is also presented. PMID:24061361

Szefler, Beata; Diudea, Mircea V

2012-12-01

416

Psychopharmacology Revisited  

Microsoft Academic Search

Comments on J. R. Snibbe's article that cites the increase in number of nonphysician mental health professionals who frequently are in contact with patients who use and abuse a wide variety of medications. The current author argues that there is no reason why a licensed clinical psychologist should not be allowed to work in an area once considered the exclusive

Nicky Edd

1976-01-01

417

Petaluma Revisited  

ERIC Educational Resources Information Center

If economic recovery occurs, land development and construction will revive simultaneously with land-use controls. Already the Federal government has affected land use by passing the Coastal Zone Management Act and the Clean Air Act. The states have also initiated land-use regulations concerning community planning and environmental quality. (MR)

Wolff, Anthony

1975-01-01

418

Palatogram revisited  

PubMed Central

It is the responsibility of the dentist to fabricate a denture that is fully functional and perfectly esthetic. One prime oral function that has always been overlooked in this regard is speech. It has been thought that speech will follow mere replacement of teeth and that it is the patient's duty to fine tune this function with practice. Phonetics, esthetics, function and comfort form the foundation of a successful prosthodontic treatment. Accurate approximation of palatal contours of a maxillary complete denture to a patient's tongue can improve speech intelligibility, if other factors such as tooth position, occlusal plane and occlusal vertical dimension are satisfactory. Customizing palatal contours of a maxillary complete denture can be accomplished by using tissue-conditioning material, which provides sufficient working time for a patient to pronounce a series of sibilant sounds while recording dynamic impression of the tongue. This article describes a technique of obtaining palatogram and customizing palatal contours of a maxillary complete denture with autopolymerizing acrylic resin to improve the intelligibility of speech. PMID:24808716

Jain, Ashish R.; Venkat Prasad, M. K.; Ariga, Padma

2014-01-01

419

Palatogram revisited.  

PubMed

It is the responsibility of the dentist to fabricate a denture that is fully functional and perfectly esthetic. One prime oral function that has always been overlooked in this regard is speech. It has been thought that speech will follow mere replacement of teeth and that it is the patient's duty to fine tune this function with practice. Phonetics, esthetics, function and comfort form the foundation of a successful prosthodontic treatment. Accurate approximation of palatal contours of a maxillary complete denture to a patient's tongue can improve speech intelligibility, if other factors such as tooth position, occlusal plane and occlusal vertical dimension are satisfactory. Customizing palatal contours of a maxillary complete denture can be accomplished by using tissue-conditioning material, which provides sufficient working time for a patient to pronounce a series of sibilant sounds while recording dynamic impression of the tongue. This article describes a technique of obtaining palatogram and customizing palatal contours of a maxillary complete denture with autopolymerizing acrylic resin to improve the intelligibility of speech. PMID:24808716

Jain, Ashish R; Venkat Prasad, M K; Ariga, Padma

2014-01-01

420

Superdiffusion revisited  

E-print Network

The concept of diffusion in collisionless space plasmas like those near the magnetopause and in the geomagnetic tail is reexamined from a fundamental statistical point of view making use of the division of particle orbits into waiting orbits and break-out into ballistic motion lying at the bottom, for instance, of L\\'evy flights and the celebrated $\\kappa$-distribution. A stringent derivation yields an anomalous diffusion coefficient increasing with time, thus describing superdiffusion. Contrary to wide belief, superdiffusion, though faster than classical, is a weak process. Absolute values of the coefficient are small due to the largeness of the anomalous collision frequency in waiting statistics compared with the infinitesimally small binary collision frequency. We provide parallel and perpendicular diffusion coefficients, determine the exponents of temporal increase, determine the power and $\\kappa$ for two-dimensional diffusion by referring to published numerical particle-in-cell simulations, fix the rang...

Treumann, R A

2014-01-01

421

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

422

The Galactic Cepheid period-luminosity relation revisited using bona fide cluster Cepheids  

NASA Astrophysics Data System (ADS)

Classical Cepheids in Galactic open clusters (cluster Cepheids: CCs) have been studied extensively for multiple decades, thanks to their importance as calibrators of the Galactic Cepheid period-luminosity relation (PLR). Here we revisit the calibration of the Galactic PLR using a new sample of CCs, since even recent calibrations show significant discrepancies. The CC sample employed for the calibration is based on the preliminary results of a self-consistent, eight-dimensional all-sky census. This census is based mostly on literature data, supplemented with high-precision radial-velocity observations from both hemispheres. New CCs are identified from our census and the degree of confidence in membership is quantified for known candidates. Using only bona fide CCs, we obtain MV = (-3.08 +/- 0.50) log P + (-0.94 +/- 0.42) mag, which is in perfect agreement with the results by Sandage, Tammann, and Reindl, albeit with larger error bars and an rms of 0.21 mag. The key to obtaining a meaningful calibration is to employ accurate cluster distance moduli and space reddening values. A homogeneous study of all bona fide host clusters would be desirable to increase precision and confidence in the calibration.

Anderson, Richard I.; Mowlavi, Nami; Eyer, Laurent

2013-02-01

423

Keratinocyte Detachment-Differentiation Connection Revisited, or Anoikis-Pityriasi Nexus Redux  

PubMed Central

Epidermis, a continuously self-renewing and differentiating organ, produces a protective stratum corneum that shields us from external chemical, physical and microbial threats. Epidermal differentiation is a multi-step process regulated by influences, some unknown, others insufficiently explored. Detachment of keratinocytes from the basement membrane is one such pro-differentiation stimulus. Here, we define the transcriptional changes during differentiation, especially those caused by detachment from the substratum. Using comprehensive transcriptional profiling, we revisited the effects of detachment as a differentiation signal to keratinocytes. We identified the genes regulated by detachment, the corresponding ontological categories and, using metaanalysis, compared the genes and categories to those regulated by other pro-differentiating stimuli. We identified 762 genes overexpressed in suspended keratinocyte, including known and novel differentiation markers, and 1427 in attached cells, including basal layer markers. Detachment induced epidermis development, cornification and desmosomal genes, but also innate immunity, proliferation inhibitors, transcription regulators and MAPKs; conversely the attached cells overexpressed cell cycle, anchoring, motility, splicing and mitochondrial genes, and both positive and negative regulators of apoptosis. Metaanalysis identified which detachment-regulated categories overlap with those induced by suprabasal location in vivo, by reaching confluency in vitro, and by inhibition of JUN kinases. Attached and in vivo basal cells shared overexpression of mitochondrial components. Interestingly, melanosome trafficking components were also overexpressed in the attached and in vivo basal keratinocytes. These results suggest that specific pro-differentiation signals induce specific features of the keratinization process, which are in vivo orchestrated into harmonious epidermal homeostasis. PMID:24960166

Banno, Tomohiro; Blumenberg, Miroslav

2014-01-01

424

Revisiting annual mean and seasonal cycle of deep meridional overturning circulation of the Indian Ocean  

NASA Astrophysics Data System (ADS)

The annual mean and seasonal cycle of the deep meridional overturning circulation (MOC) of the Indian Ocean is being revisited here using GECCO synthesis. Resulting from ocean general circulation models, the annual mean deep MOC of the Indian Ocean are generally weak with inflow in the bottom layer and outflow in the intermediate and upper layer mixing with strong Indonesian Throughflow. For seasonal cycle of deep MOC, two significant and seasonal reversed counter-rotating deep cells over full depth of water column, roughly separated by 20S, are revealed during boreal summer and winter. The coincidences of the latitude 20S with where the maximum climatological wind curl for most of seasons reveals intimate relations between the deep meridional overturning and surface winds. Dynamical decompositions on annual mean and complete seasonal cycle of the meridional overturning show varying relative contribution of each dynamical component at different time scale. For annual mean deep MOC, Ekman dynamics is found to be dominant in the region of north of 25S, particularly in upper 3000m, whereas south of 25S external and vertical shear components show remarkable "seamount" features and are compensated with much larger strengths because of topo-modulated strong western boundary topography. At seasonal time scale, dominant role of Ekman dynamics and secondary role of external mode are found in the deep cell north of 20S in January and July. However in transition seasons, vertical shear is responsible for major part of meridional overturning and Ekman dynamics has comparable contribution north of Equator.

Wang, Weiqiang; Xie, Qiang; Li, Sha; Zhu, Xiuhua

2014-05-01

425

Anharmonicity and tunneling effects in revisited vibrational O(1s) photoelectron spectrum of water gas phase.  

PubMed

The authors have revisited the description of the core-hole ionization dynamics of the oxygen atom in water by re-exploiting the high-resolution, vibrationally resolved, XPS photoelectron spectrum of gas phase at the O(1s) edge. The agreement between theory and experiments is mainly controlled by (i) the description of the tunneling behavior near the barrier top (linear H-O-H conformation) of wave functions with high vibrational quanta, and (ii) the relative displacement of the potential-energy minimum of the O(1s) final state with respect to the ground state one. Accurate change in bond angle between the neutral and core-ionized states is essential to account for the Franck-Condon factors. The O(1s) photoelectron spectrum of water is well reproduced by the molecular ab initio calculations based on density functional theory and Franck-Condon factors calculations in a double-well (2 x W) simulation of the bending motion. PMID:17581054

Carniato, Stéphane

2007-06-14

426

Gray and green revisited: a multidisciplinary perspective of gardens, gardening, and the aging process.  

PubMed

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

427

Indiana v. Davis: revisiting due process rights of permanently incompetent defendants.  

PubMed

With its landmark Jackson v. Indiana (406 U.S. 715 (1972)) decision, the United States Supreme Court ruled that states may not indefinitely confine criminal defendants solely on the basis of incompetence to stand trial. While this decision led to widespread state statutory and procedural changes, the Jackson court left unresolved whether states could indefinitely maintain criminal charges against incompetent defendants. Nearly four decades after the Jackson decision, the Indiana Supreme Court finally revisited this question in Indiana v. Davis (898 N.E.2d. 281 (Ind. 2008)), unanimously ruling that holding criminal charges over the head of a permanently incompetent defendant, when her pretrial confinement extended beyond the maximum period of any sentence the trial court could impose, violated the basic notions of fundamental fairness embodied in the Due Process Clause of the Fourteenth Amendment. In this analysis of Indiana v. Davis, the facts of the case and the court's rationale for its decision are discussed. This unique ruling is considered in light of the questions resolved and still unanswered since Jackson v. Indiana. PMID:19767504

Morris, Douglas R; Parker, George F

2009-01-01

428

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

429

Revisiting the concept of hepatosplenic schistosomiasis and its challenges using traditional and new tools.  

PubMed

Different aspects of hepatosplenic schistosomiasis are revisited here. Manson's schistosomiasis causes periportal fibrosis and portal hypertension in approximately 6% of infected subjects, usually with preservation of their hepatic function. The assessment of liver involvement is of major importance in determining the prognosis and risk of complications from schistosomiasis, such as upper digestive bleeding secondary to variceal rupture. For many years, the diagnosis of hepatosplenic schistosomiasis and liver fibrosis was made by abdominal palpation and the finding of liver and/or spleen enlargement. However, there is no consensus regarding the clinical parameters of the liver and spleen to be considered in this physical evaluation. For the last three decades, abdominal ultrasound (US) has become the best imaging technique to evaluate liver fibrosis caused by schistosomiasis mansoni. However, US is a subjective procedure and is therefore examiner-dependent. Magnetic resonance imaging (MRI) findings have provided valuable information in addition to ultrasound and clinical examination. The combination of a comprehensive history and physical examination, basic laboratory tests (a stool examination for Schistosoma mansoni eggs and a blood cell count), biomarkers for liver fibrosis/portal hypertension and imaging methods seem to offer the best approach for evaluating patients with this disease. In situations where research is involved or in patients with severe disease, MRI may be considered. PMID:24861284

Lambertucci, José Roberto

2014-01-01

430

The enigma of Gerstmann's syndrome revisited: a telling tale of the vicissitudes of neuropsychology.  

PubMed

Eighty years ago, the Austrian neurologist Josef Gerstmann observed in a few patients a concomitant impairment in discriminating their own fingers, writing by hand, distinguishing left from right and performing calculations. He claimed that this tetrad of symptoms constituted a syndromal entity, assigned it to a lesion of the dominant parietal lobe and suggested that it was due to damage of a common functional denominator. Ever since, these claims have been debated and an astute synopsis and sceptical discussion was presented 40 years ago by MacDonald Critchley in this journal. Nonetheless, Gerstmann's syndrome has continued to intrigue both clinical neurologists and researchers in neuropsychology, and more frequently than not is described in textbooks as an example of parietal lobe damage. In this review, we revisit the chequered history of this syndrome, which can be seen as a case study of the dialectic evolution of concepts in neuropsychology. In light of several modern era findings of pure cases we conclude that it is legitimate to label the conjunction of symptoms first described by Gerstmann as a 'syndrome', but that it is very unlikely that damage to the same population of cortical neurons should account for all of the four symptoms. Instead, we propose that a pure form of Gerstmann's syndrome might arise from disconnection, via a lesion, to separate but co-localized fibre tracts in the subcortical parietal white matter, a hypothesis for which we have recently provided evidence using combined imaging of functional and structural organization in the healthy brain. PMID:19903731

Rusconi, Elena; Pinel, Philippe; Dehaene, Stanislas; Kleinschmidt, Andreas

2010-02-01

431

Stochastic Gravitational Wave Background from Neutron Star r-mode Instability Revisited  

E-print Network

We revisit the possibility and detectability of a stochastic gravitational wave background (SGWB) produced by a cosmological population of newborn neutron stars (NSs) with r-mode instabilities. We show that the resultant SGWB is insensitive to the choice of CSFR models, but depends strongly on the evolving behavior of CSFR at low redshifts. Our results show that the dimensionless energy density $\\Omega_{\\rm{GW}}$ could have a peak amplitude of $\\simeq (1-3.5) \\times10^{-8}$ in the frequency range $(200-1000)$~Hz. However, such a high mode amplitude is unrealistic as it is known that the maximum value is much smaller and at most $10^{-2}$. A realistic estimate of $\\Omega_{\\rm{GW}}$ should be at least 4 orders of magnitude lower ($\\sim 10^{-12}$), which leads to a pessimistic outlook for the detection of r-mode background. We consider different pairs of terrestrial interferometers (IFOs) and compare two approaches to combine multiple IFOs in order to evaluate the detectability of this GW background. Constraints...

Zhu, Xing-Jiang; Zhu, Zong-Hong

2011-01-01

432

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

433

The light curve of SN 1987A revisited: constraining production masses of radioactive nuclides  

E-print Network

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) x 10^{-2} Msun and M(57Ni) = (4.1 +- 1.8) x 10^{-3} Msun. Our best fit 44Ti mass is M(44Ti) = (0.55 +- 0.17) x 10^{-4} Msun, which is in disagreement with the much higher (3.1 +- 0.8) x 10^{-4} Msun recently derived from INTEGRAL observations. The associated uncertainties far exceed the best fit values f...

Seitenzahl, I R; Magkotsios, G

2014-01-01

434

Phobos 2/ASPERA data revisited: Planetary ion escape rate from Mars near the 1989 solar maximum  

NASA Astrophysics Data System (ADS)

Insights about the near-Mars space environment from Mars Express observations have motivated a revisit of the Phobos 2/ASPERA ion data from 1989. We have expanded the analysis to now include all usable heavy ion (O+, O2+, CO2+) measurements from the circular orbits of Phobos 2. Phobos 2/ASPERA ion fluxes in the Martian tail are compared with previous results obtained by the instruments on Phobos 2. Further validation of the measurement results is obtained by comparing IMP-8 and Phobos 2/ASPERA solar wind ion fluxes, taking into account the time lag between Earth and Mars. Heavy ion flux measurements from 18 circular equatorial orbits around Mars are bin-averaged to a grid, using the MSE (electric field) frame of reference. The binned data are subsequently integrated to determine the total escape rate of planetary ions. From this we derive a total planetary heavy ion escape rate of (2-3) × 1025 s-1 from Mars for the 1989 solar maximum.

Ramstad, Robin; Futaana, Yoshifumi; Barabash, Stas; Nilsson, Hans; Martin Del Campo B, Sergio; Lundin, Rickard; Schwingenschuh, Konrad

2013-02-01

435

Phobos 2/ASPERA data revisited: Planetary ion escape rate from Mars near the 1989 solar maximum  

NASA Astrophysics Data System (ADS)

Insights about the near-Mars space environment from Mars Express observations have motivated a revisit of the ASPERA-Phobos 2 ion data from 1989. The Sun's more active past makes the escape rate measured during the extremely high 1989 solar maximum crucial for understanding the evolution of the Martian atmosphere. Our escape rate analysis is expanded to include all usable heavy ion measurements (O+, O++, O2+) from the circular orbits of Phobos 2. We used an empirical model for the ion distribution function in the Martian tail, based on Mars Express data, to reexamine the Phobos 2 data. The newly calculated fluxes in the Martian tail were also recalibrated against IMP-8 measurements of the solar wind and Phobos 2-TAUS ion measurements in the tail. Heavy ion flux measurements from 18 circular equatorial orbits around Mars have were bin-averaged to a grid, using the MSE (electric field) frame of reference and data from the MAGMA magnetometer. The heavy ion flux grid reveals a disturbed Martian magnetosphere and is integrated to yield a total planetary heavy ion escape rate of 2.2 × 1025 s-1 from Mars for the 1989 solar maximum.

Ramstad, Robin; Futaana, Yoshifumi; Barabash, Stas; Nilsson, Hans; Fedorov, Andrei; del Campo Barraza, Sergio Martin; Lundin, Rickard; Schwingenschuh, Konrad

2013-04-01

436

COPS science questions revisited: What have we learned so far from COPS?  

NASA Astrophysics Data System (ADS)

The Convective and Orographically-induced Precipitation Study (COPS) was an international field campaign carried out in summer 2007 with the overall goal to advance the quality of forecasts of orographically-induced convective precipitation by 4-dimensional observations and modeling of its life cycle. The pre-convective environment, the formation of clouds and the onset and development of precipitation were observed in a low-mountain area in south-western Germany and eastern France covering the Vosges Mountains, the Rhine Valley, and the Black Forest Mountains during 18 Intensive Observations Periods from June 1 to August 31, 2007, under different forcing conditions. Meanwhile, in the nearly five years since the COPS field phase, a large number of results on analyses of selected COPS IOPs and of continuous measurements during the COPS period have been published; in a special issue of the Quarterly Journal of the Royal Meteorological Society alone, 21 papers appeared in January 2011. A second special issue on COPS results is currently in preparation for the Meteorologische Zeitschrift (MetZ). In this contribution, we will revisit the original science questions of COPS, summarize the results gained so far from COPS, and discuss questions which still remain open.

Behrendt, A.; Wulfmeyer, V.; Kottmeier, Ch.; Richard, E.; Dorninger, M.; Di Girolamo, P.; Corsmeier, U.; Kalthoff, N.; Bauer, H.-S.

2012-04-01

437

Infantile scurvy: an old diagnosis revisited with a modern dietary twist.  

PubMed

Ascorbic acid (vitamin C) is necessary for the formation of collagen, reducing free radicals, and aiding in iron absorption. Scurvy, a disease of dietary ascorbic acid deficiency, is uncommon today. Indeed, implementation of dietary recommendations largely eradicated infantile scurvy in the US in the early 1900s. We present a case of an otherwise healthy 2-year-old Caucasian girl who presented with refusal to walk secondary to pain in her lower extremities, generalized irritability, sleep disturbance, and malaise. The girl's parents described feeding the patient an organic diet recommended by the Church of Scientology that included a boiled mixture of organic whole milk, barley, and corn syrup devoid of fruits and vegetables. Physical examination revealed pale, bloated skin with edematous, violaceous gums and loosening of a few of her teeth. Dermatologic findings included xerosis, multiple scattered ecchymoses of the extremities, and perifollicular hemorrhage. Laboratory and radiographic evaluation confirmed the diagnosis of scurvy. The patient showed dramatic improvement after only 3 days of treatment with oral ascorbic acid and significant dietary modification. In this case report, we revisit the old diagnosis of scurvy with a modern dietary twist secondary to religious practices. This case highlights the importance of taking a detailed dietary history when evaluating diseases involving the skin. PMID:17428115

Burk, Cynthia J; Molodow, Rona

2007-01-01

438

Revisiting the Spiral Density Wave Paradigm in M51 with PAWS  

NASA Astrophysics Data System (ADS)

The interacting Whirlpool galaxy M51 is a favorite test-bed for spiral arm density wave theories, and studies of the spiral morphology and kinematics show evidence for the offset alignment of the gaseous, young and old stellar tracers predicted by theory, as well as strong non-circular gas streaming motions. Now, the unparalleled high resolution of the PAWS (PdBI Arcsecond Whirlpool Survey, PI:Schinnerer) data, combined with exceptional multi-wavelength coverage, makes it an ideal target for revisiting the density wave picture and for examining the influence of bar and spiral instabilities on secular evolution. We present an updated view of the current dynamical state of the system, with particular emphasis on GMC scales. Gas kinematics at these scales--available for the first time in a spiral outside the Local Group--are a critical tool for assessing the influence of spiral arms on the organization of the ISM. To interpret the role of pressure and shear on GMC formation and evolution, we combine these data with a 2D map of spiral arm torques newly derived from the stellar mass distribution mapped with S4G 3.6 and 4.5 ?m images. We also compare gas inflow and star formation rates throughout the disk, assembling a view of the spatial-dependence of consumption timescales for the current gas reservoir.

Meidt, Sharon; Schinnerer, E.; Garcia-Burillo, S.; Hughes, A.; Colombo, D.; Pety, J.; Leroy, A.; Schuster, K.; Kramer, C.; Dumas, G.; Dobbs, C.; Thompson, T.

2012-01-01

439

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

SciTech Connect

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.

Saykally, Richard J; Cappa, Chris D.; Smith, Jared D.; Wilson, Kevin R.; Saykally, Richard J.

2008-02-16

440

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

441

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

442

Polyploidy and its effect on evolutionary success: old questions revisited with new tools  

PubMed Central

Polyploidy, the condition of possessing more than two complete genomes in a cell, has intrigued biologists for almost a century. Polyploidy is found in many plants and some animal species and today we know that polyploidy has had a role in the evolution of all angiosperms. Despite its widespread occurrence, the direct effect of polyploidy on evolutionary success of a species is still largely unknown. Over the years many attractive hypotheses have been proposed in an attempt to assign functionality to the increased content of a duplicated genome. Among these hypotheses are the proposal that genome doubling confers distinct advantages to a polyploid and that these advantages allow polyploids to thrive in environments that pose challenges to the polyploid's diploid progenitors. This article revisits these long-standing questions and explores how the integration of recent genomic developments with ecological, physiological and evolutionary perspectives has contributed to addressing unresolved problems about the role of polyploidy. Although unsatisfactory, the current conclusion has to be that despite significant progress, there still isn't enough information to unequivocally answer many unresolved questions about cause and effect of polyploidy on evolutionary success of a species. There is, however, reason to believe that the increasingly integrative approaches discussed here should allow us in the future to make more direct connections between the effects of polyploidy on the genome and the responses this condition elicits from the organism living in its natural environment. PMID:23149459

Madlung, A

2013-01-01

443

Brownian motion and anomalous diffusion revisited via a fractional Langevin equation  

E-print Network

In this paper we revisit the Brownian motion on the basis of {the fractional Langevin equation which turns out to be a particular case of the generalized Langevin equation introduced by Kubo in 1966. The importance of our approach is to model the Brownian motion more realistically than the usual one based on the classical Langevin equation, in that it takes into account also the retarding effects due to hydrodynamic back-flow, i.e. the added mass and the Basset memory drag. We provide the analytical expressions of the correlation functions (both for the random force and the particle velocity) and of the mean squared particle displacement. The random force has been shown to be represented by a superposition of the usual white noise with a "fractional" noise. The velocity correlation function is no longer expressed by a simple exponential but exhibits a slower decay, proportional to t^{-3/2} for long times, which indeed is more realistic. Finally, the mean squared displacement is shown to maintain, for sufficiently long times, the linear behaviour which is typical of normal diffusion, with the same diffusion coefficient of the classical case. However, the Basset history force induces a retarding effect in the establishing of the linear behaviour, which in some cases could appear as a manifestation of anomalous diffusion to be correctly interpreted in experimental measurements.

Francesco Mainardi; Antonio Mura; Francesco Tampieri

2010-04-20

444

Antisolar differential rotation of the K1-giant sigma Geminorum revisited  

E-print Network

Context. Surface differential rotation and other global surface flows on magnetically active stars are among the observable manifestations of the stellar dynamo working underneath. Therefore, such observations are important for stellar dynamo theory and useful constraints for solar dynamo studies as well. Aims. The active K1-giant component of the long-period RS CVn-type binary system sigma Gem and its global surface flow pattern is revisited. 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 from the formerly used 4 to 17 we expect a more robust determination of the differential surface rotation law. In addition, we present a new time-series Doppler imaging study of sigma Gem using our advanced surface reconstruction code iMap for a dataset collected in 2006/07. R...

Kovari, Zs; Künstler, A; Carroll, T A; Strassmeier, K G; Vida, K; Olah, K; Bartus, J; Weber, M

2014-01-01

445

Irrigation effects in the northern lake states: Wisconsin central sands revisited.  

PubMed

Irrigated agriculture has expanded greatly in the water-rich U.S. northern lake states during the past half century. Source water there is usually obtained from glacial aquifers strongly connected to surface waters, so irrigation has a potential to locally decrease base flows in streams and water levels in aquifers, lakes, and wetlands. During the nascent phase of the irrigation expansion, water availability was explored in works of some fame in the Wisconsin central sands by Weeks et al. (1965) on the Little Plover River and Weeks and Stangland (1971) on "headwater area" streams and lakes. Four decades later, and after irrigation has grown to a dominant landscape presence, we revisited irrigation effects on central sands hydrology. Irrigation effects have been substantial, on average decreasing base flows by a third or more in many stream headwaters and diminishing water levels by more than a meter in places. This explains why some surface waters have become flow and stage impaired, sometimes to the point of drying, with attendant losses of aquatic ecosystems. Irrigation exerts its effects by increasing evapotranspiration by an estimated 45 to 142 mm/year compared with pre-irrigated land cover. We conclude that irrigation water availability in the northern lake states and other regions with strong groundwater-surface water connections is tied to concerns for surface water health, requiring a focus on managing the upper few meters of aquifers on which surface waters depend rather than the depletability of an aquifer. PMID:21707615

Kraft, George J; Clancy, Katherine; Mechenich, David J; Haucke, Jessica

2012-01-01

446

Re-visiting the relations: Galactic thin disc age-velocity dispersion relation  

E-print Network

The velocity dispersion of stars in the solar neighbourhood thin disc increases with time after star formation. Nordstrom et al. (2004) is the most recent observational attempt to constrain the age-velocity dispersion relation. They fitted the age-velocity dispersion relations of each Galactic cardinal direction space velocity component, U (towards the Galactic centre), V (in the direction of Galactic rotation) and W (towards the North Galactic Pole), with power laws and interpreted these as evidence for continuous heating of the disc in all directions throughout its lifetime. We re-visit these relations with their data and use Famaey et al. (2005) to show that structure in the local velocity distribution function distorts the in-plane (U and V) velocity distributions away from Gaussian so that a dispersion is not an adequate parametrization of their functions. The age-sigma(W) relation can however be constrained because the sample is well phase-mixed vertically. We do not find any local signature of the stellar warp in the Galactic disc. Vertical disc heating does not saturate at an early stage. Our new result is that a power law is not required by the data: disc heating models that saturate after ~ 4.5 Gyr are equally consistent with observations.

G. M. Seabroke; G. Gilmore

2007-07-06

447

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

448

Nuclear magnetic resonance signal dynamics of liquids in the presence of distant dipolar fields, revisited  

PubMed Central

The description of the nuclear magnetic resonance magnetization dynamics in the presence of long-range dipolar interactions, which is based upon approximate solutions of Bloch–Torrey equations including the effect of a distant dipolar field, has been revisited. New experiments show that approximate analytic solutions have a broader regime of validity as well as dependencies on pulse-sequence parameters that seem to have been overlooked. In order to explain these experimental results, we developed a new method consisting of calculating the magnetization via an iterative formalism where both diffusion and distant dipolar field contributions are treated as integral operators incorporated into the Bloch–Torrey equations. The solution can be organized as a perturbative series, whereby access to higher order terms allows one to set better boundaries on validity regimes for analytic first-order approximations. Finally, the method legitimizes the use of simple analytic first-order approximations under less demanding experimental conditions, it predicts new pulse-sequence parameter dependencies for the range of validity, and clarifies weak points in previous calculations. PMID:19425789

Barros, Wilson; Gochberg, Daniel F.; Gore, John C.

2009-01-01

449

H I Kinematics of the Large Magellanic Cloud revisited : Evidence of possible infall and outflow  

E-print Network

The neutral atomic Hydrogen (H I) kinematics of the Large Magellanic Cloud (LMC) is revisited in light of two new proper motion estimates. We analysed the intensity weighted H I velocity maps of the ATCA/Parkes and 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. The value of position angle (PA) of kinematic major axis estimated using ATCA/Parkes data 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. Using ATCA/Parkes data, most of the H I gas in the LMC is found to be located in the disk. We detected 12.1% of the data points as kinematic outliers. We identified the well-known Arm E, Arm S, Arm W, Arm B and a new stream, Outer Arm, as part of outlier components. The GASS data analysis brings out the velocity d...

Indu, G

2014-01-01

450

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

451

Fertility control in historical China revisited: New Methods for an Old Debate  

PubMed Central

We revisit the debate over deliberate control of reproduction in historical China through a reanalysis of data from the Qing (1644-911) Imperial Lineage that accounts for physiological or other differences between couples that affected their chances of having children. Even though studies of contemporary and historical European fertility suggest that failing to control for such differences may obscure evidence of parity-specific control, previous studies of historical Chinese fertility have not accounted for them. We show that in the Lineage, failure to account for such differences leads the association between number of children already born and the chances of having another birth to appear to be positive, but that once they are accounted for properly, the relationship is inverted. Based on this, we conclude that lineage members adjusted their reproductive behavior based on the number of children. We also show that the sex composition and survival of previous births affected reproductive behavior. We conclude by suggesting that one way forward in the ongoing debate over fertility control in historical China is through application of such methods to other datasets and comparison of results. We also suggest that progress in the debate over fertility in historical China has been impeded by confusion over the definition of fertility control, so that some behaviors are recognized as fertility control by some parties in the debate but not others. PMID:21151712

Lee, James Z.

2010-01-01

452

Revisiting discrete dark matter model: ? 13 ? 0 and ? R dark matter  

NASA Astrophysics Data System (ADS)

We revisit the discrete dark matter model with the A 4 flavor symmetry originally introduced by M.Hirsch et.al. We show that radiative corrections can lead to non-zero ? 13 and the non-zero mass for the lightest neutrino. We find an interesting relation among neutrino mixing parameters and it indicates the sizable deviation of s 23 from the maximal angle s {23/2} = 1/2 and the degenerate mass spectrum for neutrinos. Also we study the possibilities that the right-handed neutrino is a dark matter candidate. Assuming that the thermal freeze-out explains observed dark matter abundance, TeV-scale right-handed neutrino and flavored scalar bosons are required. In such a case, the flavor symmetry plays an important role for the suppression of lepton flavor violating processes as well as for the stability of dark matter. We show that this scenario is viable within currently existing constraints from collider, low energy experiments and cosmological observations.

Hamada, Yuta; Kobayashi, Tatsuo; Ogasahara, Atsushi; Omura, Yuji; Takayama, Fumihiro; Yasuhara, Daiki

2014-10-01

453

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

454

Post-Tanner stages of droplet spreading: the energy balance approach revisited  

NASA Astrophysics Data System (ADS)

The spreading of a circular liquid drop on a solid substrate can be described in terms of the time evolution of its base radius R(t). In complete wetting, the quasistationary regime (far away from initial and final transients) typically obeys the so-called Tanner law, with R~t?T, ?T = 1/10. Late-time spreading may differ significantly from the Tanner law: in some cases the drop does not thin down to a molecular film and instead reaches an equilibrium pancake-like shape; in other situations, as revealed by recent experiments with spontaneously spreading nematic crystals, the growth of the base radius accelerates after the Tanner stage. Here we demonstrate that these two seemingly conflicting trends can be reconciled within a suitably revisited energy balance approach, by taking into account the line tension contribution to the driving force of spreading: a positive line tension is responsible for the formation of pancake-like structures, whereas a negative line tension tends to lengthen the contact line and induces an accelerated spreading (a transition to a faster power law for R(t) than in the Tanner stage).

Mechkov, S.; Cazabat, A. M.; Oshanin, G.

2009-11-01

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

Post-Tanner stages of droplet spreading: the energy balance approach revisited  

E-print Network

The spreading of a circular liquid drop on a solid substrate can be described by the time evolution of its base radius R(t). In complete wetting the quasistationary regime (far away from initial and final transients) typically obeys the so-called Tanner law, with R t^alpha_T, alpha_T=1/10. Late-time spreading may differ significantly from the Tanner law: in some cases the drop does not thin down to a molecular film and instead reaches an equilibrium pancake-like shape; in other situations, as revealed by recent experiments with spontaneously spreading nematic crystals, the growth of the base radius accelerates after the Tanner stage. Here we demonstrate that these two seemingly conflicting trends can be reconciled within a suitably revisited energy balance approach, by taking into account the line tension contribution to the driving force of spreading: a positive line tension is responsible for the formation of pancake-like structures, whereas a negative line tension tends to lengthen the contact line and induces an accelerated spreading (a transition to a faster power law for R(t) than in the Tanner stage).

Serguei Mechkov; Anne-Marie Cazabat; Gleb Oshanin

2009-09-10

457

Andreev-Lifshitz supersolid revisited for a few electrons on a square lattice. I  

NASA Astrophysics Data System (ADS)

In 1969, Andreev and Lifshitz have conjectured the existence of a supersolid phase taking place at zero temperature between the quantum liquid and the solid. In this and a succeeding paper, we re-visit this issue for a few polarized electrons (spinless fermions) interacting via a U/r Coulomb repulsion on a two dimensional L×L square lattice with periodic boundary conditions and nearest neighbor hopping t. This paper is restricted to the magic number of particles N = 4 for which a square Wigner molecule is formed when U increases and to the size L = 6 suitable for exact numerical diagonalizations. When the Coulomb energy to kinetic energy ratio rs = UL/(2t) reaches a value rsF 10, there is a level crossing between ground states of different momenta. Above rsF, the mesoscopic crystallization proceeds through an intermediate regime ( rsF < rs < rsW 28) where unpaired fermions with a reduced Fermi energy co-exist with a strongly paired, nearly solid assembly. We suggest that this is the mesoscopic trace of the supersolid proposed by Andreev and Lifshitz. When a random substrate is included, the level crossing at rsF is avoided and gives rise to a lower threshold rsF(W) < rsF where two usual approximations break down: the Wigner surmise for the distribution of the first energy excitation and the Hartree-Fock approximation for the ground state.

Katomeris, G.; Selva, F.; Pichard, J.-L.

2003-02-01

458

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

459

Three-Dimensional Wavelet-Based Multifractal Method: The Need for Revisiting the Multifractal Description of Turbulence Dissipation Data  

NASA Astrophysics Data System (ADS)

We generalize the wavelet transform modulus maxima (WTMM) method to multifractal analysis of 3D random fields. This method is calibrated on synthetic 3D monofractal fractional Brownian fields and on 3D multifractal singular cascade measures as well as their random function counterpart obtained by fractional integration. Then we apply the 3D WTMM method to the dissipation field issued from 3D isotropic turbulence simulations. We comment on the need to revisit previous box-counting analyses which have failed to estimate correctly the corresponding multifractal spectra because of their intrinsic inability to master nonconservative singular cascade measures.

Kestener, Pierre; Arneodo, Alain

2003-11-01

460

A three-dimensional wavelet based multifractal method : about the need of revisiting the multifractal description of turbulence dissipation data  

E-print Network

We generalize the wavelet transform modulus maxima (WTMM) method to multifractal analysis of 3D random fields. This method is calibrated on synthetic 3D monofractal fractional Brownian fields and on 3D multifractal singular cascade measures as well as their random function counterpart obtained by fractional integration. Then we apply the 3D WTMM method to the dissipation field issue from 3D isotropic turbulence simulations. We comment on the need to revisiting previous box-counting analysis which have failed to estimate correctly the corresponding multifractal spectra because of their intrinsic inability to master non-conservative singular cascade measures.

Pierre Kestener; Alain Arneodo

2003-02-28

461

Three-dimensional wavelet-based multifractal method: the need for revisiting the multifractal description of turbulence dissipation data.  

PubMed

We generalize the wavelet transform modulus maxima (WTMM) method to multifractal analysis of 3D random fields. This method is calibrated on synthetic 3D monofractal fractional Brownian fields and on 3D multifractal singular cascade measures as well as their random function counterpart obtained by fractional integration. Then we apply the 3D WTMM method to the dissipation field issued from 3D isotropic turbulence simulations. We comment on the need to revisit previous box-counting analyses which have failed to estimate correctly the corresponding multifractal spectra because of their intrinsic inability to master nonconservative singular cascade measures. PMID:14611583

Kestener, Pierre; Arneodo, Alain

2003-11-01

462

Impact of the Lund Integrated Medicines Management (LIMM) model on medication appropriateness and drug-related hospital revisits  

Microsoft Academic Search

Purpose  To examine the impact of systematic medication reconciliations upon hospital admission and of a medication review while in\\u000a hospital on the number of inappropriate medications and unscheduled drug-related hospital revisits in elderly patients.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  This was a prospective, controlled study in 210 patients, aged 65 years or older, who were admitted to one of three internal\\u000a medicine wards at a University Hospital

Lina M. Hellström; Åsa Bondesson; Peter Höglund; Patrik Midlöv; Lydia Holmdahl; Eva Rickhag; Tommy Eriksson

2011-01-01

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

Revisit control of a phased-array radar for tracking maneuvering targets when supported by a precision electronic support measures (ESM) sensor  

Microsoft Academic Search

Since phased array radars have the ability to perform adaptive sampling of the target trajectory by radar beam positioning, proper control of the radar has the potential for significantly improving many aspects associated with the tracking of multiple maneuvering targets. When supported by additional sensors, the sampling of the phased array radar can be reduced significantly. However, controlling the revisit

Gregory A. Watson; William D. Blair

1994-01-01

465

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

466

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

467

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

468

Apple Burrknot Borers in New York Revisited Pest status and chemical control of borers infesting apple burrknots in New York State  

E-print Network

Apple Burrknot Borers in New York ­ Revisited Pest status and chemical control of borers infesting apple burrknots in New York State DAVID P. KAIN, RICHARD W. STRAUB AND ARTHUR M. AGNELLO Department damage to dwarf apple trees caused by American plum borer, a survey was conducted in the major apple

Agnello, Arthur M.

469

hat makes a good mentor? Naturejobs often revisits this complex query. On page 791 of this issue, Nature presents an in-depth  

E-print Network

W hat makes a good mentor? Naturejobs often revisits this complex query. On page 791 of this issue are only as good as the scientists who produce them, then becoming a super-mentor is as worthy Production Manager: Stephen Russell To send materials use London address above. Tel: +44 (0) 20 7843 4816 Fax

Cai, Long

470

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

471

Tensions of Reimagining Our Roles as Teacher Educators in a Third Space: Revisiting a Co/Autoethnography through a Faculty Lens  

ERIC Educational Resources Information Center

This co/autoethnography uses our lens as university faculty to examine how engaging in a year-long self-study with mentors nurtured a complicated third space where we could together begin to reimagine our roles as teacher educators. Two secondary faculty members and a doctoral assistant used co/autoethnography to revisit a collaborative self-study…

Taylor, Monica; Klein, Emily J.; Abrams, Linda

2014-01-01

472

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; Nemeth, Sandor; Jeney, Zsigmond; Bercsenyi, Miklos; Orban, Laszlo

2013-01-01

473

The I2 dissociation mechanisms in the chemical oxygen-iodine laser revisited.  

PubMed

The recently suggested mechanism of I(2) dissociation in the chemical oxygen-iodine laser (COIL) [K. Waichman, B. D. Barmashenko, and S. Rosenwaks, J. Appl. Phys. 106, 063108 (2009); and J. Chem. Phys. 133, 084301 (2010)] was largely based on the suggestion of V. N. Azyazov, S. Yu. Pichugin, and M. C. Heaven [J. Chem. Phys. 130, 104306 (2009)] that the vibrational population of O(2)(a) produced in the chemical generator is high enough to play an essential role in the dissociation. The results of model calculations based on this mechanism agreed very well with measurements of the small signal gain g, I(2) dissociation fraction F, and temperature T in the COIL. This mechanism is here revisited, following the recent experiments of M. V. Zagidullin [Quantum Electron. 40, 794 (2010)] where the observed low population of O(2)(b, v = 1) led to the conclusion that the vibrational population of O(2)(a) at the outlet of the generator is close to thermal equilibrium value. This value corresponds to a very small probability, ?0.05, of O(2)(a) energy pooling to the states O(2)(X,a,b, v > 0). We show that the dissociation mechanism can reproduce the experimentally observed values of g, F, and T in the COIL only if most of the energy released in the processes of O(2)(a) energy pooling and O(2)(b) quenching by H(2)O ends up as vibrational energy of the products, O(2)(X,a,b), where the vibrational states v = 2 and 3 are significantly populated. We discuss possible reasons for the differences in the suggested vibrational population and explain how these differences can be reconciled. PMID:22755574

Waichman, K; Barmashenko, B D; Rosenwaks, S

2012-06-28

474

Post-Newtonian approximation for isolated systems by matched asymptotic expansions I. General structure revisited  

E-print Network

In recent years post-Newtonian approximations for isolated slowly-moving systems in general relativity have been studied by means of matched asymptotic expansions. A paper by Poujade & Blanchet in 2002 made great progress by effectively reducing the use of such expansions to an algorithmic form. It gave systematic procedures for the development of both near-zone and far-zone asymptotic expansions, avoiding the divergent integrals which often bedevilled such methods, and showed that these two expansions could be made to match exactly, a result described there as somewhat remarkable. This paper revisits that work and shows that there is unfortunately an error in it which invalidates the results of the matching process as given therein. The present paper identifies that error and shows how it may be corrected to give valid matching results. The correction is presented in a redevelopment somewhat different from that of their paper. This shows that far from being somewhat remarkable, it is in fact inevitable that the match is exact. It is indeed remarkable that they could carry both expansions to the point at which matching becomes possible, but if it can be done at all, then the match is necessarily exact. A companion paper will apply this asymptotic matching to a model problem in which the correct near-zone expansion was obtained by approximation from an exact solution. It will be shown that there is a discrepancy between this expansion and results from the original development of Poujade & Blanchet but that the corrected development presented here reproduces the result of the model problem exactly.

W. G. Dixon

2013-11-23

475

Anik-E1 and E2 satellite failures of January 1994 revisited  

NASA Astrophysics Data System (ADS)

The consecutive failures of the geosynchronous Anik-E1 communication satellite on January 20, 1994, and Anik-E2 about nine hours later on January 21 (both incidents occurred on January 20 local time) received considerable publicity because the malfunctions of the satellites disrupted television and computer data transmissions across Canada, as well as telephone services to remote northern communities for hours. This often-cited event is revisited here with materials not covered before. Using publicly available information, Anik-E failure details, media coverage, recovery effort and cost incurred are first presented. This is then followed by scrutiny of space weather conditions pertinent to the occurrences of the Anik-E upsets. We trace the space weather episode's inception on the Sun, propagation through interplanetary medium, and manifestation in magnetic field variations as well as in energetic electron flux increases, and its eventual impact on the Anik-Es. The genesis of the energetic electron enhancements that have been blamed for the satellite malfunctions is thus traceable via high-speed solar wind stream with Alfven wave fluctuations to a longitudinally wide coronal hole on the Sun. Furthermore, strong magnetic pulsations preceding electron flux peaks indicate Pc5 ULF (Ultra Low Frequency) waves as a probable acceleration mechanism for the energetic electron flux enhancement that resulted in the internal charging of the Anik-Es. The magnetic fluctuations may even be possible triggers for the subsequent discharge that caused the satellites to malfunction. This incident illustrates that satellite operators should be on alert for elevated high-energy electron environment that is above established thresholds, as specifications in satellite design may not render a satellite immune from internal charging.

Lam, H.-L.; Boteler, D. H.; Burlton, B.; Evans, J.

2012-10-01

476

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

477

Central Indian Ocean Plate Tectonics Between Chrons 34 to 20 (83 to 42 Ma) Revisited  

NASA Astrophysics Data System (ADS)

The Indian Ocean is the result of East Gondwanaland fragmentation and dispersal since Jurassic. Its complex plate tectonic history is the result of several major events such as the Kerguelen and Reunion hotspot inception and the Indo-Eurasian collision. Indian and French scientists have collected a large amount of marine geophysical data in the conjugate basins of the northern and southern Indian Ocean, respectively. Using these data and under the auspices of an Indo-French collaborative project, we revisited the Central Indian (CIB), Crozet (CZB) and Madagascar (MDB) basins to understand their evolution. We created a common database consisting of magnetic data from 148 cruises belonging to the Indian and French scientists along with the so-called international data archived at NGDC. From these magnetic profiles, (1) we identified the anomalies using the inter-profile correlation and forward modelling as well as a detailed analysis of the characteristic shape of the anomalies (including the tiny wiggles); (2) we precisely located the magnetic isochrons using the analytic signal technique; and (3) we validated these isochrons by plate reconstructions. We present the updated magnetic isochrons and the associated fracture zones (depicted from the free air gravity anomaly derived from satellite altimetry) in the Central Indian, Crozet and Madagascar basins between chron 34ny (83 Ma) and chron 20ny (42.5 Ma). The 1399 magnetic anomaly crossings (846, 287 and 266 picks from CIB, CZB, and MDB respectively) enabled us to estimate improved finite rotation parameters for Indian-Antarctic and Indian-African plate boundaries and provide better constrained plate reconstruction models of the study area for closer time intervals ( ~2 Ma).

Yatheesh, V.; Dyment, J.; Bhattacharya, G.; Jensen, J.; Ramprasad, T.; Royer, J.; Kamesh Raju, K.; Patriat, P.; Chaubey, A.; Choi, Y.; Srinivas, K.

2008-12-01

478

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

479

The growth of galactic bulges through mergers in ? CDM haloes revisited - I. Present-day properties  

NASA Astrophysics Data System (ADS)

We use the combined data sets of the Millennium I and II cosmological simulations to revisit the impact of mergers in the growth of bulges in central galaxies in the ? cold dark matter (?CDM) scenario. We seed galaxies within the growing CDM haloes using semi-empirical relations to assign stellar and gaseous masses, and an analytic treatment to estimate the transfer of stellar mass to the bulge of the remnant after a galaxy merger. We find that this model roughly reproduces the observed correlation between the bulge-to-total mass (B/T) ratio and stellar mass (M*) in present-day central galaxies as well as their observed demographics, although low-mass B/T < 0.1 (bulgeless) galaxies might be scarce relative to the observed abundance. In our merger-driven scenario, bulges have a composite stellar population made of (i) stars acquired from infalling satellites, (ii) stars transferred from the primary disc due to merger-induced perturbations and (iii) newly formed stars in starbursts triggered by mergers. We find that the first two are the main channels of mass assembly, with the first one being dominant for massive galaxies, creating large bulges with different stellar populations than those of the inner discs, while the second is dominant for intermediate/low-mass galaxies and creates small bulges with similar stellar populations to the inner discs. We associate the dominion of the first (second) channel to classical (pseudo) bulges, and compare the predicted fractions to observations. We emphasize that our treatment does not include other mechanisms of bulge growth such as intrinsic secular processes in the disc or misaligned gas accretion. Interestingly, we find that the evolution of the stellar and gaseous contents of the satellite as it spirals towards the central galaxy is a key ingredient in setting the morphology of the remnant galaxy, and that a good match to the observed bulge demographics occurs when this evolution proceeds closely to that of the central galaxy.