Sample records for fronto-occipital fasciculus revisited

  1. Frontal terminations for the inferior fronto-occipital fascicle: anatomical dissection, DTI study and functional considerations on a multi-component bundle.

    PubMed

    Sarubbo, Silvio; De Benedictis, Alessandro; Maldonado, Igor L; Basso, Gianpaolo; Duffau, Hugues

    2013-01-01

    The anatomy and functional role of the inferior fronto-occipital fascicle (IFOF) remain poorly known. We accurately analyze its course and the anatomical distribution of its frontal terminations. We propose a classification of the IFOF in different subcomponents. Ten hemispheres (5 left, 5 right) were dissected with Klingler's technique. In addition to the IFOF dissection, we performed a 4-T diffusion tensor imaging study on a single healthy subject. We identified two layers of IFOF. The first one is superficial and antero-superiorly directed, terminating in the inferior frontal gyrus. The second is deeper and consists of three portions: posterior, middle and anterior. The posterior component terminates in the middle frontal gyrus (MFG) and dorso-lateral prefrontal cortex. The middle component terminates in the MFG and lateral orbito-frontal cortex. The anterior one is directed to the orbito-frontal cortex and frontal pole. In vivo tractography study confirmed these anatomical findings. We suggest that the distribution of IFOF fibers within the frontal lobe corresponds to a fine functional segmentation. IFOF can be considered as a "multi-function" bundle, with each anatomical subcomponent subserving different brain processing. The superficial layer and the posterior component of the deep layer, which connects the occipital extrastriate, temporo-basal and inferior frontal cortices, might subserve semantic processing. The middle component of the deep layer could play a role in a multimodal sensory-motor integration. Finally, the anterior component of the deep layer might be involved in emotional and behavioral aspects. PMID:22200882

  2. ForPeerReview Dissecting the Uncinate Fasciculus: Disorders,

    E-print Network

    Olson, Ingrid

    ForPeerReview Dissecting the Uncinate Fasciculus: Disorders, Controversies, and a Hypothesis: Uncinate Fasciculus Page 1 Dissecting the Uncinate Fasciculus: Disorders, Controversies, and a Hypothesis the Uncinate Fasciculus: Disorders, Controversies, and a Hypothesis 1. Introduction The uncinate fasciculus (UF

  3. Virtual in Vivo Interactive Dissection of White Matter Fasciculi in the Human Brain

    Microsoft Academic Search

    Marco Catani; Robert J. Howard; Sinisa Pajevic; Derek K. Jones

    2002-01-01

    This work reports the use of diffusion tensor magnetic resonance tractography to visualize the three-dimensional (3D) structure of the major white matter fasciculi within living human brain. Specifically, we applied this technique to visualize in vivo (i) the superior longitudinal (arcuate) fasciculus, (ii) the inferior longitudinal fasciculus, (iii) the superior fronto-occipital (subcallosal) fasciculus, (iv) the inferior fronto-occipital fasciculus, (v) the

  4. Dissecting the uncinate fasciculus: disorders, controversies and a hypothesis

    PubMed Central

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

    2013-01-01

    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

  5. The Role of the Arcuate Fasciculus in Conduction Aphasia

    ERIC Educational Resources Information Center

    Bernal, Byron; Ardila, Alfredo

    2009-01-01

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

  6. 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

  7. Right arcuate fasciculus abnormality in chronic fatigue syndrome.

    PubMed

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

    2015-02-01

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

  8. Superior longitudinal fasciculus and language functioning in healthy aging.

    PubMed

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

    2014-05-01

    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

  9. Delineation of the Inferior Longitudinal Fasciculus in Subjects with 22q11.2 Deletion Syndrome

    E-print Network

    Delineation of the Inferior Longitudinal Fasciculus in Subjects with 22q11.2 Deletion Syndrome E11.2 Deletion Syndrome (22q11DS) represents a population at high risk for developing schizophrenia in adulthood. Learning disabilities and deficits in visual memory have been reported in children with 22q11DS

  10. 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

  11. Diffusion tensor imaging in autism spectrum disorders: Preliminary evidence of abnormal neural connectivity

    PubMed Central

    Jou, Roger J.; Jackowski, Andrea P.; Papademetris, Xenophon; Rajeevan, Nallakkandi; Staib, Lawrence H.; Volkmar, Fred R.

    2011-01-01

    Objective This study indirectly tested the hypothesis that individuals with autism spectrum disorders (ASDs) have impaired neural connections between the amygdala, fusiform face area, and superior temporal sulcus, key processing nodes of the “social brain.” This would be evidenced by abnormalities in the major fibre tracts known to connect these structures, including the inferior longitudinal fasciculus and inferior fronto-occipital fasciculus. Method Magnetic resonance diffusion tensor imaging was performed on 20 right-handed males (ASD = 10, controls = 10) with a mean age 13.5 ± 4.0 years. Subjects were group-matched according to age, full-scale IQ, handedness, and ethnicity. Fractional anisotropy was used to assess structural integrity of major fibre tracts. Voxel-wise comparison of white matter fractional anisotropy was conducted between groups using ANCOVA adjusting for age, full-scale IQ, and brain volume. Volumes of interest were identified using predetermined probability and cluster thresholds. Follow-up tractography was performed to confirm the anatomic location of all volumes of interest. Results All volumes of interest were regions of lower FA and were observed primarily in pericallosal regions and temporal lobes. As confirmed by tractography, affected white matter structures included the inferior longitudinal fasciculus/inferior fronto-occipital fasciculus, superior longitudinal fasciculus, and corpus callosum/cingulum. Notably, some volumes of interest were adjacent to the fusiform face area, bilaterally, corresponding to involvement of the inferior longitudinal fasciculus. The largest effect sizes were noted for volumes of interest in the right anterior radiation of the corpus callosum/cingulum and right fusiform face area (inferior longitudinal fasciculus). Conclusions This study provides preliminary evidence of impaired neural connectivity in the corpus callosum/cingulum and temporal lobes involving the inferior longitudinal fasciculus/inferior fronto-occipital fasciculus and superior longitudinal fasciculus in ASDs. These findings provide preliminary support for aberrant neural connectivity between the amygdala, fusiform face area, and superior temporal sulcus – temporal lobe structures critical for normal social perception and cognition. PMID:21128874

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2013-11-01

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

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

    PubMed

    Coppens, Christian

    2009-01-01

    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

  15. 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

    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

    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,…

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

    PubMed

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

    2015-03-01

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

  17. Bidirectional iterative parcellation of diffusion weighted imaging data: separating cortical regions connected by the arcuate fasciculus and extreme capsule.

    PubMed

    Patterson, Dianne K; Van Petten, Cyma; Beeson, Pélagie M; Rapcsak, Steven Z; Plante, Elena

    2014-11-15

    This paper introduces a Bidirectional Iterative Parcellation (BIP) procedure designed to identify the location and size of connected cortical regions (parcellations) at both ends of a white matter tract in diffusion weighted images. The procedure applies the FSL option "probabilistic tracking with classification targets" in a bidirectional and iterative manner. To assess the utility of BIP, we applied the procedure to the problem of parcellating a limited set of well-established gray matter seed regions associated with the dorsal (arcuate fasciculus/superior longitudinal fasciculus) and ventral (extreme capsule fiber system) white matter tracts in the language networks of 97 participants. These left hemisphere seed regions and the two white matter tracts, along with their right hemisphere homologues, provided an excellent test case for BIP because the resulting parcellations overlap and their connectivity via the arcuate fasciculi and extreme capsule fiber systems are well studied. The procedure yielded both confirmatory and novel findings. Specifically, BIP confirmed that each tract connects within the seed regions in unique, but expected ways. Novel findings included increasingly left-lateralized parcellations associated with the arcuate fasciculus/superior longitudinal fasciculus as a function of age and education. These results demonstrate that BIP is an easily implemented technique that successfully confirmed cortical connectivity patterns predicted in the literature, and has the potential to provide new insights regarding the architecture of the brain. PMID:25173414

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

  20. Axons from the medial habenular nucleus are topographically sorted in the fasciculus retroflexus.

    PubMed

    Ichijo, Hiroyuki; Toyama, Tomoko

    2014-08-22

    We generated transgenic mice lines with a construct consisting of the zif268/egr1 promoter and the gene for the normal long-life yellow fluorescent protein (Venus) with a membrane localization sequence. One of the lines exhibited topographic labeling in the medial habenular nucleus (MHb) during postnatal development, which confirmed the previous findings that the medial, lateral, and dorsal areas of MHb project to the ventral, dorsal, and lateral parts of the interpeduncular nucleus, respectively. In addition, the membranous localization of the labeling allowed us to observe spacial arrangement of the labeled axons in the fasciculus retroflexus (FR) in the transgenic mice. Here, we report topographic sorting of the MHb axons in the FR. At postnatal day (P) 5 and P10, the labeled axons from the medial MHb were fasciculated and ran through the narrow path in the core of the FR. At P24, the labeled axons from the medial and dorsal MHb were fasciculated and ran through the broad path in the FR core. No labeling occurred in the lateral MHb throughout development; correspondingly, parts of the FR core remained unlabeled. The results indicated that the axons from the medial and dorsal areas of the MHb are grouped together in the FR of this transgenic line and are sorted out from the axons from the lateral MHb. PMID:25145706

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

    PubMed Central

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

    2014-01-01

    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

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

    PubMed

    Gullick, Margaret M; Booth, James R

    2014-07-01

    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

  3. Atypical hemispheric asymmetry in the arcuate fasciculus of completely nonverbal children with autism.

    PubMed

    Wan, Catherine Y; Marchina, Sarah; Norton, Andrea; Schlaug, Gottfried

    2012-04-01

    Despite the fact that as many as 25% of the children diagnosed with autism spectrum disorders are nonverbal, surprisingly little research has been conducted on this population. In particular, the mechanisms that underlie their absence of speech remain unknown. Using diffusion tensor imaging, we compared the structure of a language-related white matter tract (the arcuate fasciculus, AF) in five completely nonverbal children with autism to that of typically developing children. We found that, as a group, the nonverbal children did not show the expected left-right AF asymmetry--rather, four of the five nonverbal children actually showed the reversed pattern. It is possible that this unusual pattern of asymmetry may underlie some of the severe language deficits commonly found in autism, particularly in children whose speech fails to develop. Furthermore, novel interventions (such as auditory-motor mapping training) designed to engage brain regions that are connected via the AF may have important clinical potential for facilitating expressive language in nonverbal children with autism. PMID:22524376

  4. Sex differences of uncinate fasciculus structural connectivity in individuals with conduct disorder.

    PubMed

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

    2014-01-01

    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

  5. The vertical occipital fasciculus: a century of controversy resolved by in vivo measurements.

    PubMed

    Yeatman, Jason D; Weiner, Kevin S; Pestilli, Franco; Rokem, Ariel; Mezer, Aviv; Wandell, Brian A

    2014-12-01

    The vertical occipital fasciculus (VOF) is the only major fiber bundle connecting dorsolateral and ventrolateral visual cortex. Only a handful of studies have examined the anatomy of the VOF or its role in cognition in the living human brain. Here, we trace the contentious history of the VOF, beginning with its original discovery in monkey by Wernicke (1881) and in human by Obersteiner (1888), to its disappearance from the literature, and recent reemergence a century later. We introduce an algorithm to identify the VOF in vivo using diffusion-weighted imaging and tractography, and show that the VOF can be found in every hemisphere (n = 74). Quantitative T1 measurements demonstrate that tissue properties, such as myelination, in the VOF differ from neighboring white-matter tracts. The terminations of the VOF are in consistent positions relative to cortical folding patterns in the dorsal and ventral visual streams. Recent findings demonstrate that these same anatomical locations also mark cytoarchitectonic and functional transitions in dorsal and ventral visual cortex. We conclude that the VOF is likely to serve a unique role in the communication of signals between regions on the ventral surface that are important for the perception of visual categories (e.g., words, faces, bodies, etc.) and regions on the dorsal surface involved in the control of eye movements, attention, and motion perception. PMID:25404310

  6. The Plasticity of the Superior Longitudinal Fasciculus as a Function of Musical Expertise: A Diffusion Tensor Imaging Study

    PubMed Central

    Oechslin, Mathias S.; Imfeld, Adrian; Loenneker, Thomas; Meyer, Martin; Jäncke, Lutz

    2009-01-01

    Previous neuroimaging studies have demonstrated that musical expertise leads to functional alterations in language processing. We utilized diffusion tensor imaging (DTI) to investigate white matter plasticity in musicians with absolute pitch (AP), relative pitch and non-musicians. Using DTI, we analysed the fractional anisotropy (FA) of the superior longitudinal fasciculus (SLF), which is considered the most primary pathway for processing and production of speech and music. In association with different levels of musical expertise, we found that AP is characterized by a greater left than right asymmetry of FA in core fibres of the SLF. A voxel-based analysis revealed three clusters within the left hemisphere SLF that showed significant positive correlations with error rates only for AP-musicians in an AP-test, but not for musicians without AP. We therefore conclude that the SLF architecture in AP musicians is related to AP acuity. In order to reconcile our observations with general aspects of development of fibre bundles, we introduce the Pioneer Axon Thesis, a theoretical approach to formalize axonal arrangements of major white matter pathways. PMID:20161812

  7. Extensive White Matter Abnormalities in Patients with First-Episode Schizophrenia: A Diffusion Tensor Imaging (DTI) Study

    PubMed Central

    Lee, Sang-Hyuk; Kubicki, Marek; Asami, Takeshi; Seidman, Larry J.; Goldstein, Jill M.; Mesholam-Gately, Raquelle I.; McCarley, Robert W.; Shenton, Martha E.

    2013-01-01

    Background Previous voxelwise Diffusion Tensor Imaging (DTI) investigations of white matter in first-episode schizophrenia (FESZ) have been limited to the analysis of Fractional Anisotropy (FA) and mean diffusivity (MD), with their findings inconsistent in terms of the anatomical locations and extent of abnormalities. This study examines white matter abnormalities in FESZ, compared with healthy controls, using a tract-based spatial statistics (TBSS) approach applied to multiple measures of tract integrity, and correlates these findings with symptom severity. Methods Seventeen first-episode patients with schizophrenia and seventeen age- and gender-matched healthy controls (HC) participated in this imaging study where FA, MD, and axial and radial diffusivity were compared between the two groups using TBSS. Results First-episode patients with schizophrenia showed lower FA values in the genu and body of corpus callosum, the internal capsule, the external capsule, the fornix, the superior, inferior fronto-occipital fasciculus, the cingulum, and the uncinate fasciculus compared with HC. Increased MD and radial diffusivity were shown in virtually all white matter regions. There was no significant difference, however, observed for axial diffusivity between the two groups. Pearson correlation analysis showed that the FA values of the right inferior fronto-occipital fasciculus were positively correlated with positive symptoms, negative symptoms, and total correct items of the Wisconsin Card Sorting Test. FA values of right external capsule also showed significant positive correlation with category completed scores of the WCST. Conclusions These data suggest extensive, possibly myelin related white matter disruptions in FESZ. PMID:23290268

  8. Differences in white matter reflect atypical developmental trajectory in autism: A Tract-based Spatial Statistics study?

    PubMed Central

    Bakhtiari, Reyhaneh; Zürcher, Nicole R.; Rogier, Ophélie; Russo, Britt; Hippolyte, Loyse; Granziera, Cristina; Araabi, Babak Nadjar; Nili Ahmadabadi, Majid; Hadjikhani, Nouchine

    2012-01-01

    Autism is a neurodevelopmental disorder in which white matter (WM) maturation is affected. We assessed WM integrity in 16 adolescents and 14 adults with high-functioning autism spectrum disorder (ASD) and in matched neurotypical controls (NT) using diffusion weighted imaging and Tract-based Spatial Statistics. Decreased fractional anisotropy (FA) was observed in adolescents with ASD in tracts involved in emotional face processing, language, and executive functioning, including the inferior fronto-occipital fasciculus and the inferior and superior longitudinal fasciculi. Remarkably, no differences in FA were observed between ASD and NT adults. We evaluated the effect of age on WM development across the entire age range. Positive correlations between FA values and age were observed in the right inferior fronto-occipital fasciculus, the left superior longitudinal fasciculus, the corpus callosum, and the cortical spinal tract of ASD participants, but not in NT participants. Our data underscore the dynamic nature of brain development in ASD, showing the presence of an atypical process of WM maturation, that appears to normalize over time and could be at the basis of behavioral improvements often observed in high-functioning autism. PMID:24179736

  9. Grief revisited.

    PubMed

    Ng, B Y

    2005-06-01

    The article serves to examine the cultural influences on attitudes towards the deceased and bereaved, as well as on the practice of mourning, and to revisit normal and pathological variants of grief. Grief is a subjective state of psychological and physiological reaction to the loss of a loved one. Reaction to the loss is experienced internally in a uniform manner across cultures. However, mourning, the voluntary social expression of the loss, varies from culture to culture. Rituals provide a standardised mode of behaviour, which helps to relieve the sense of uncertainty or loss. There were reports of ghost sightings involving foreign tourists in the 6 worst-hit southern provinces in Thailand following the tsunami tragedy. This phenomenon of "mass hallucinations" is understandable from the cultural perspective. New models of grief have been developed to account for the individuality and diversity of grief and to encompass the social, behavioural and spiritual dimensions of loss as well as those of the psychological and physical. Clinically, the duration of grief reactions varies widely, depending on the nature of the loss and the connection to the deceased. In the case of the tsunami tragedy, with relatives missing, homes swept away and familiar neighbourhoods turned into wastelands, many victims are likely to have complicated grief. Traumatic grief, which includes a prominent component of separation distress characterised by yearning and searching and frequent "bittersweet" recollections of the deceased, has been associated with long-term dysfunction. Grief work utilising the traumatic grief treatment protocol appears to be a promising intervention. PMID:16021224

  10. 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 ...

  11. Google Scholar revisited

    Microsoft Academic Search

    Péter Jacsó

    2008-01-01

    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

  12. Anodic Polarization Curves Revisited

    ERIC Educational Resources Information Center

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

    2013-01-01

    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…

  13. Technological innovation processes revisited

    Microsoft Academic Search

    Antonio Cantisani

    2006-01-01

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

  14. Revisiting Curriculum Potential

    ERIC Educational Resources Information Center

    Deng, Zongyi

    2011-01-01

    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…

  15. Colloquial Hebrew Imperatives Revisited

    ERIC Educational Resources Information Center

    Bolozky, Shmuel

    2009-01-01

    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…

  16. Concept Image Revisited

    ERIC Educational Resources Information Center

    Bingolbali, Erhan; Monaghan, John

    2008-01-01

    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…

  17. T2 lesion location really matters: a 10 year follow-up study in primary progressive multiple sclerosis

    PubMed Central

    Bodini, B; Battaglini, M; De Stefano, N; Khaleeli, Z; Barkhof, F; Chard, D; Filippi, M; Montalban, X; Polman, C; Rovaris, M; Rovira, A; Samson, R; Miller, D; Thompson, A

    2010-01-01

    Objectives Prediction of long term clinical outcome in patients with primary progressive multiple sclerosis (PPMS) using imaging has important clinical implications, but remains challenging. We aimed to determine whether spatial location of T2 and T1 brain lesions predicts clinical progression during a 10-year follow-up in PPMS. Methods Lesion probability maps of the T2 and T1 brain lesions were generated using the baseline scans of 80 patients with PPMS who were clinically assessed at baseline and then after 1, 2, 5 and 10?years. For each patient, the time (in years) taken before bilateral support was required to walk (time to event (TTE)) was used as a measure of progression rate. The probability of each voxel being ‘lesional’ was correlated with TTE, adjusting for age, gender, disease duration, centre and spinal cord cross sectional area, using a multiple linear regression model. To identify the best, independent predictor of progression, a Cox regression model was used. Results A significant correlation between a shorter TTE and a higher probability of a voxel being lesional on T2 scans was found in the bilateral corticospinal tract and superior longitudinal fasciculus, and in the right inferior fronto-occipital fasciculus (p<0.05). The best predictor of progression rate was the T2 lesion load measured along the right inferior fronto-occipital fasciculus (p=0.016, hazard ratio 1.00652, 95% CI 1.00121 to 1.01186). Conclusion Our results suggest that the location of T2 brain lesions in the motor and associative tracts is an important contributor to the progression of disability in PPMS, and is independent of spinal cord involvement. PMID:20627965

  18. Revisiting Dialogues and Monologues

    ERIC Educational Resources Information Center

    Kvernbekk, Tone

    2012-01-01

    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…

  19. PTH revisited12

    Microsoft Academic Search

    Peter A. Friedman

    2004-01-01

    PTH revisited. Recent investigations of parathyroid hormone (PTH) have advanced our understanding of its circulating forms as well as its action. It is now clear that first-generation immunoradiometric assays of so-called intact “PTH” not only measured full-length PTH(1–84) but also recognized large PTH fragments lacking the amino-terminus. New, second generation assays detect only full-length PTH. Under diverse pathological settings, second

  20. Brain white matter organisation in adolescence is related to childhood cerebral responses to facial expressions and harm avoidance.

    PubMed

    Taddei, Matilde; Tettamanti, Marco; Zanoni, Annalisa; Cappa, Stefano; Battaglia, Marco

    2012-07-16

    While white matter structural integrity is likely to influence the responses to social-emotional stimuli and emotional regulation during development, no longitudinal data are available on such relationships. We investigated the relationships between white matter Fractional Anisotropy (FA) derived by DTI voxelwise Tract Based Spatial Statistics (TBSS) and tractography measured at ages 14-15, and cerebral event-related N400 amplitudes in response to happy, neutral and angry facial expressions and Cloninger's Harm Avoidance (HA) measured at ages 7-9. Whole-skeleton TBSS analyses revealed reduced FA associated to smaller N400 amplitudes in response to anger, and to higher HA. Region-of-Interest TBSS analyses showed high correlations (ranging -0.69-0.82, p<0.01-0.001) between FA and N400 amplitudes across the Inferior Longitudinal, the Inferior Frontoccipital, and the left Uncinate Fasciculus, and between FA and Harm Avoidance in right Uncinate Fasciculus (-0.71, p<0.01). Tractography showed that these relationships were mainly present in the left Inferior Longitudinal and the right Inferior Fronto-Occipital Fasciculus for N400 amplitudes, and in the right Uncinate Fasciculus for HA. Ventral limbic pathways' white matter organisation affects the neural responses to expressions - such as anger - that are perceptually more challenging and/or communicate social rejection, and compounds the neural pathways that predispose to avoidant behaviour and shyness with strangers. PMID:22484203

  1. White Matter Tracts Associated with Set-Shifting in Healthy Aging

    PubMed Central

    Perry, Michele E; McDonald, Carrie R.; Hagler, Donald J.; Gharapetian, Lusineh; Kuperman, Joshua M.; Koyama, Alain K.; Dale, Anders M.; McEvoy, Linda K.

    2009-01-01

    Attentional set-shifting ability, commonly assessed with the Trail Making Test (TMT), decreases with increasing age in adults. Since set-shifting performance relies on activity in widespread brain regions, deterioration of the white matter tracts that connect these regions may underlie the age-related decrease in performance. We used an automated fiber tracking method to investigate the relationship between white matter integrity in several cortical association tracts and TMT performance in a sample of 24 healthy adults, 21 – 80 years. Diffusion tensor images were used to compute average fractional anisotropy (FA) for five cortical association tracts, the corpus callosum (CC), and the corticospinal tract (CST), which served as a control. Results showed that advancing age was associated with declines in set-shifting performance and with decreased FA in the CC and in association tracts that connect frontal cortex to more posterior brain regions, including the inferior fronto-occipital fasciculus (IFOF), uncinate fasciculus (UF), and superior longitudinal fasciculus (SLF). Declines in average FA in these tracts, and in average FA of the right inferior longitudinal fasciculus (ILF), were associated with increased time to completion on the set-shifting subtask of the TMT but not with the simple sequencing subtask. FA values in these tracts were strong mediators of the effect of age on set-shifting performance. Automated tractography methods can enhance our understanding of the fiber systems involved in performance of specific cognitive tasks and of the functional consequences of age-related changes in those systems. PMID:19540862

  2. Reframing in dentistry: revisited.

    PubMed

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

    2013-01-01

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

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

    PubMed

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

    2015-01-01

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

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

    PubMed

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

    2015-02-01

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

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

    PubMed Central

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

    2014-01-01

    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

  6. Fossil turbulence revisited

    E-print Network

    Carl H. Gibson

    1999-04-27

    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.

  7. Revisiting the schism.

    PubMed

    Litsios, Socrates

    2014-01-01

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

  8. Revisiting Lambert's problem

    NASA Astrophysics Data System (ADS)

    Izzo, Dario

    2015-01-01

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

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

    PubMed

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

    2013-01-01

    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

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

    PubMed Central

    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

    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

  11. Clinical correlations of microstructural changes in progressive supranuclear palsy.

    PubMed

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

    2014-10-01

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

  12. In Vivo Tractography of Fetal Association Fibers

    PubMed Central

    Mitter, Christian; Prayer, Daniela; Brugger, Peter C.; Weber, Michael; Kasprian, Gregor

    2015-01-01

    Association fibers connect different cortical areas within the same hemisphere and constitute an essential anatomical substrate for a diverse range of higher cognitive functions. So far a comprehensive description of the prenatal in vivo morphology of these functionally important pathways is lacking. In the present study, diffusion tensor imaging (DTI) and tractography were used to visualize major association fiber tracts and the fornix in utero in preselected non-motion degraded DTI datasets of 24 living unsedated fetuses between 20 and 34 gestational weeks (GW). The uncinate fasciculus and inferior fronto-occipital fasciculus were depicted as early as 20 GW, while in vivo 3D visualization of the inferior longitudinal fasciculus, cingulum and fornix was successful in older fetuses during the third trimester. Provided optimal scanning conditions, in utero DTI and tractography have the potential to provide a more accurate anatomical definition of developing neuronal networks in the human fetal brain. Knowledge about the normal prenatal 3D association tract morphology may serve as reference for their assessment in common developmental diseases. PMID:25742520

  13. Gray- and white-matter anatomy of absolute pitch possessors.

    PubMed

    Dohn, Anders; Garza-Villarreal, Eduardo A; Chakravarty, M Mallar; Hansen, Mads; Lerch, Jason P; Vuust, Peter

    2015-05-01

    Absolute pitch (AP), the ability to identify a musical pitch without a reference, has been examined behaviorally in numerous studies for more than a century, yet only a few studies have examined the neuroanatomical correlates of AP. Here, we used MRI and diffusion tensor imaging to investigate structural differences in brains of musicians with and without AP, by means of whole-brain vertex-wise cortical thickness (CT) analysis and tract-based spatial statistics (TBSS) analysis. APs displayed increased CT in a number of areas including the bilateral superior temporal gyrus (STG), the left inferior frontal gyrus, and the right supramarginal gyrus. Furthermore, we found higher fractional anisotropy in APs within the path of the inferior fronto-occipital fasciculus, the uncinate fasciculus, and the inferior longitudinal fasciculus. The findings in gray matter support previous studies indicating an increased left lateralized posterior STG in APs, yet they differ from previous findings of thinner cortex for a number of areas in APs. Finally, we found a relation between the white-matter results and the CT in the right parahippocampal gyrus. In this study, we present novel findings in AP research that may have implications for the understanding of the neuroanatomical underpinnings of AP ability. PMID:24304583

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

    PubMed

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

    2014-06-27

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

  15. Higher integrity of the motor and visual pathways in long-term video game players

    PubMed Central

    Du, Guijin; Yang, Yongxin; Qin, Wen; Li, Xiaodong; Zhang, Quan

    2015-01-01

    Long term video game players (VGPs) exhibit superior visual and motor skills compared with non-video game control subjects (NVGCs). However, the neural basis underlying the enhanced behavioral performance remains largely unknown. To clarify this issue, the present study compared the whiter matter integrity within the corticospinal tracts (CST), the superior longitudinal fasciculus (SLF), the inferior longitudinal fasciculus (ILF), and the inferior fronto-occipital fasciculus (IFOF) between the VGPs and the NVGCs using diffusion tensor imaging. Compared with the NVGCs, voxel-wise comparisons revealed significantly higher fractional anisotropy (FA) values in some regions within the left CST, left SLF, bilateral ILF, and IFOF in VGPs. Furthermore, higher FA values in the left CST at the level of cerebral peduncle predicted a faster response in visual attention tasks. These results suggest that higher white matter integrity in the motor and higher-tier visual pathways is associated with long-term video game playing, which may contribute to the understanding on how video game play influences motor and visual performance. PMID:25805981

  16. Higher integrity of the motor and visual pathways in long-term video game players.

    PubMed

    Zhang, Yang; Du, Guijin; Yang, Yongxin; Qin, Wen; Li, Xiaodong; Zhang, Quan

    2015-01-01

    Long term video game players (VGPs) exhibit superior visual and motor skills compared with non-video game control subjects (NVGCs). However, the neural basis underlying the enhanced behavioral performance remains largely unknown. To clarify this issue, the present study compared the whiter matter integrity within the corticospinal tracts (CST), the superior longitudinal fasciculus (SLF), the inferior longitudinal fasciculus (ILF), and the inferior fronto-occipital fasciculus (IFOF) between the VGPs and the NVGCs using diffusion tensor imaging. Compared with the NVGCs, voxel-wise comparisons revealed significantly higher fractional anisotropy (FA) values in some regions within the left CST, left SLF, bilateral ILF, and IFOF in VGPs. Furthermore, higher FA values in the left CST at the level of cerebral peduncle predicted a faster response in visual attention tasks. These results suggest that higher white matter integrity in the motor and higher-tier visual pathways is associated with long-term video game playing, which may contribute to the understanding on how video game play influences motor and visual performance. PMID:25805981

  17. Asymmetry of White Matter Pathways in Developing Human Brains.

    PubMed

    Song, Jae W; Mitchell, Paul D; Kolasinski, James; Ellen Grant, P; Galaburda, Albert M; Takahashi, Emi

    2014-05-01

    Little is known about the emergence of structural asymmetry of white matter tracts during early brain development. We examined whether and when asymmetry in diffusion parameters of limbic and association white matter pathways emerged in humans in 23 brains ranging from 15 gestational weeks (GW) up to 3 years of age (11 ex vivo and 12 in vivo cases) using high-angular resolution diffusion imaging tractography. Age-related development of laterality was not observed in a limbic connectional pathway (cingulum bundle or fornix). Among the studied cortico-cortical association pathways (inferior longitudinal fasciculus [ILF], inferior fronto-occipital fasciculus, and arcuate fasciculus), only the ILF showed development of age-related laterality emerging as early as the second trimester. Comparisons of ages older and younger than 40 GW revealed a leftward asymmetry in the cingulum bundle volume and a rightward asymmetry in apparent diffusion coefficient and leftward asymmetry in fractional anisotropy in the ILF in ages older than 40 GW. These results suggest that morphometric asymmetry in cortical areas precedes the emergence of white matter pathway asymmetry. Future correlative studies will investigate whether such asymmetry is anatomically/genetically driven or associated with functional stimulation. PMID:24812082

  18. White matter microstructure in bipolar disorder is influenced by the serotonin transporter gene polymorphism 5-HTTLPR.

    PubMed

    Benedetti, F; Bollettini, I; Poletti, S; Locatelli, C; Lorenzi, C; Pirovano, A; Smeraldi, E; Colombo, C

    2015-03-01

    Bipolar disorder (BD) is associated with signs of widespread disruption of white matter (WM) integrity. A polymorphism in the promoter of the serotonin transporter (5-HTTLPR) influenced functional cortico-limbic connectivity in healthy subjects and course of illness in BD, with the short (s) allele being associated with lower functional connectivity, and with earlier onset of illness and poor response to treatment. We tested the effects of 5-HTTLPR on diffusion tensor imaging (DTI) measures of WM microstructure in 140 inpatients, affected by a major depressive episode in course of BD, of Italian descent. We used whole brain tract-based spatial statistics in the WM skeleton with threshold-free cluster enhancement of DTI measures of WM microstructure: axial, radial and mean diffusivity and fractional anisotropy. Compared with l/l homozygotes, 5-HTTLPR*s carriers showed significantly increased radial and mean diffusivity in several brain WM tracts, including corpus callosum, cingulum bundle, uncinate fasciculus, corona radiata, thalamic radiation, inferior and superior longitudinal fasciculus and inferior fronto-occipital fasciculus. An increase of mean and radial diffusivity, perpendicular to the main axis of the WM tract, is thought to signify increased space between fibers, thus suggesting demyelination or dysmyelination, or loss of bundle coherence. The effects of 5-HTTLPR on the anomalous emotional processing in BD might be mediated by changes of WM microstructure in key WM tracts contributing to the functional integrity of the brain. PMID:25704032

  19. White matter changes in preclinical Alzheimer's disease: a magnetic resonance imaging-diffusion tensor imaging study on cognitively normal older people with positive amyloid ? protein 42 levels.

    PubMed

    Molinuevo, José Luis; Ripolles, Pablo; Simó, Marta; Lladó, Albert; Olives, Jaume; Balasa, Mircea; Antonell, Anna; Rodriguez-Fornells, Antoni; Rami, Lorena

    2014-12-01

    The aim of this study was to use diffusion tensor imaging measures to determine the existence of white matter microstructural differences in the preclinical phases of Alzheimer's disease, assessing cognitively normal older individuals with positive amyloid ? protein (A?42) levels (CN_A?42+) on the basis of normal cognition and cerebrospinal fluid A?42 levels below 500 pg/mL. Nineteen CN_A?42+ and 19 subjects with A?42 levels above 500 pg/mL (CN_A?42-) were included. We encountered increases in axial diffusivity (AxD) in CN_A?42+ relative to CN_A?42- in the corpus callosum, corona radiata, internal capsule, and superior longitudinal fasciculus bilaterally, and also in the left fornix, left uncinate fasciculus, and left inferior fronto-occipital fasciculus. However, no differences were found in other diffusion tensor imaging indexes. Cognitive reserve scores were positively associated with AxD exclusively in the CN_A?42+ group. The finding of AxD alteration together with preserved fractional anisotropy, mean diffusivity, and radial diffusivity indexes in the CN_A?42+ group may indicate that, subtle axonal changes may be happening in the preclinical phases of Alzheimer's disease, whereas white matter integrity is still widely preserved. PMID:25002037

  20. Searle's"Dualism Revisited"

    SciTech Connect

    P., Henry

    2008-11-20

    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.

  1. L134N Revisited

    NASA Astrophysics Data System (ADS)

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

    2001-07-01

    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.

  2. Revisiting caspases in sepsis

    PubMed Central

    Aziz, M; Jacob, A; Wang, P

    2014-01-01

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

  3. The "Mushroom Cloud" Demonstration Revisited

    ERIC Educational Resources Information Center

    Panzarasa, Guido; Sparnacci, Katia

    2013-01-01

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

  4. Internet Governance revisited: Think decentralization!

    E-print Network

    Schweik, Charles M.

    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

  5. Economic History Revisited: New Uncertainties

    E-print Network

    Economic History Revisited: New Uncertainties I n the last Sitar-Rutgers Regional Report, we the fourth straight year of improvement, it was nowhere near "breakout" status. For the first time in six years, the state's job growth fell behind that of the nation. A brief discussion of rebenchmarking

  6. Quantum Damped Harmonic Oscillator Revisited

    E-print Network

    Fujii, Kazuyuki

    2007-01-01

    In this paper we revisit the quantum damped harmonic oscillator and construct an interesting approximate solution in the operator algebra level. Namely, we first give the general solution to the Lindblad form (equation) and next construct an approximate solution to the full equation by use of it. Our method is a milestone to construct the general solution.

  7. Extended equal area criterion revisited

    Microsoft Academic Search

    X. Xue; L. Wehenkel; R. Belhomme; P. Rousseaux; M. Pavella; E. Euxibie; B. Heilbronn; J. F. Lesigne

    1992-01-01

    This paper reports on a case study conducted on the EHV French power system in order to revisit the extended equal area criterion and test its suitability as a fast transient stability indicator. The assumptions underlying the method are reexamined, causes liable to invalidate them are identified, and indices are devised to automatically circumvent them. The selection of candidate critical

  8. Revisiting the Mysterious Mpemba Effect

    Microsoft Academic Search

    R. P. Gamage; S. R. D. Rosa

    2008-01-01

    The effect of hot water freezing faster than cold water is mentioned in Greek literature. However, it came out as a scientific phenomenon during the last few decades and is known as Mpemba effect since 1969. But there is an inadequacy of explanation which was a challenge to the modern science. Hence, it is an important issue to revisit this

  9. Oxidative phosphorylation revisited.

    PubMed

    Nath, Sunil; Villadsen, John

    2015-03-01

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

  10. Revisiting Random Utility Models A dissertation presented

    E-print Network

    Chen, Yiling

    #12;Revisiting Random Utility Models A dissertation presented by Hossein Azari Souani to The School 2014 Hossein Azari Souani All rights reserved. #12;Dissertation Advisor: Professor David C. Parkes Author: Hossein Azari Souani Revisiting Random Utility Models Abstract This thesis explores extensions

  11. Radiolytic Cryovolcanism Revisited

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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].

  12. Sex differences in white matter development during adolescence: A DTI study

    PubMed Central

    Wang, Yingying; Adamson, Chris; Yuan, Weihong; Altaye, Mekibib; Rajagopal, Akila; Byars, Anna W.; Holland, Scott K.

    2012-01-01

    Adolescence is a complex transitional period in human development, composing physical maturation, cognitive and social behavioral changes. The objective of this study is to investigate sex differences in white matter development and the associations between intelligence and white matter microstructure in the adolescent brain using diffusion tensor imaging (DTI) and tract-based spatial statistics (TBSS). In a cohort of 16 typically-developing adolescents aged 13 to 17 years, longitudinal DTI data were recorded from each subject at two time points that were one year apart. We used TBSS to analyze the diffusion indices including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Our results suggest that boys (13–18 years) continued to demonstrate white matter maturation, whereas girls appeared to reach mature levels earlier. In addition, we identified significant positive correlations between FA and full-scale intelligence quotient (IQ) in the right inferior fronto-occipital fasciculus when both sexes were looked at together. Only girls showed significant positive correlations between FA and verbal IQ in the left cortico-spinal tract and superior longitudinal fasciculus. The preliminary evidence presented in this study supports that boys and girls have different developmental trajectories in white matter microstructure. PMID:22954903

  13. Early frontal structural and functional changes in mild white matter lesions relevant to cognitive decline.

    PubMed

    Sun, Xuan; Liang, Ying; Wang, Jun; Chen, Kewei; Chen, Yaojing; Zhou, Xiaoqing; Jia, Jianjun; Zhang, Zhanjun

    2014-01-01

    White matter lesions (WMLs) are of considerable research interest because of their high prevalence and serious consequences, such as stroke and dementia. Most existing studies of WMLs have focused on severe WMLs, but mild WMLs, which are clinically and fundamentally significant, have been largely neglected. The present study is a comprehensive investigation on the injury pattern and on the anatomical, functional, and cognitive changes related to mild WMLs. These results may provide better understanding mild WMLs. Fifty-one human subjects with mild WMLs and 49 control participants completed serial neuropsychological tests and underwent a 3-T magnetic resonance imaging (MRI) scan that included diffusion tensor imaging, a resting-state functional MRI, and a structural MRI. We found declines in cognitive functions such as global function, executive function, and episodic memory in mild WMLs subjects. The white matter injuries in the mild WMLs subjects were mainly in the fibers that projected to frontal areas, while gray matter structures were relatively intact. The overall resting state function of the frontal area was significantly increased. The integrity of the neural fibers in the inferior fronto-occipital fasciculus and the inferior longitudinal fasciculus was significantly correlated with the cognitive scores in executive function and episodic memory in both the control and the mild WMLs group. These findings demonstrate that mild WMLs subjects exhibit abnormalities in both white matter structure and functional intrinsic brain activity and that such changes are related to several types of cognitive dysfunction. PMID:24346215

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2014-06-01

    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. PMID:24048702

  16. Individual differences in white matter anatomy predict dissociable components of reading skill in adults.

    PubMed

    Welcome, Suzanne E; Joanisse, Marc F

    2014-08-01

    We used diffusion tensor imaging (DTI) to investigate relationships between white matter anatomy and different reading subskills in typical-reading adults. A series of analytic approaches revealed that phonological decoding ability is associated with anatomical markers that do not relate to other reading-related cognitive abilities. Thus, individual differences in phonological decoding might relate to connectivity between a network of cortical regions, while skills like sight word reading might rely less strongly on integration across regions. Specifically, manually-drawn ROIs and probabilistic tractography revealed an association between the volume and integrity of white matter underlying primary auditory cortex and nonword reading ability. In a related finding, more extensive cross-hemispheric connections through the isthmus of the corpus callosum predicted better phonological decoding. Atlas-based white matter ROIs demonstrated that relationships with nonword reading were strongest in the inferior fronto-occipital fasciculus and uncinate fasciculus that connect occipital and anterior temporal cortex with inferior frontal cortex. In contrast, tract volume underlying the left angular gyrus was related to nonverbal IQ. Finally, connectivity underlying functional ROIs that are differentially active during phonological and semantic processing predicted nonword reading and reading comprehension, respectively. Together, these results provide important insights into how white matter anatomy may relate to both typical reading subskills, and perhaps a roadmap for understanding neural connectivity in individuals with reading impairments. PMID:24704456

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

    PubMed Central

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

    2014-01-01

    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

  18. White matter and visuospatial processing in autism: a constrained spherical deconvolution tractography study.

    PubMed

    McGrath, Jane; Johnson, Katherine; O'Hanlon, Erik; Garavan, Hugh; Gallagher, Louise; Leemans, Alexander

    2013-10-01

    Autism spectrum disorders (ASDs) are associated with a marked disturbance of neural functional connectivity, which may arise from disrupted organization of white matter. The aim of this study was to use constrained spherical deconvolution (CSD)-based tractography to isolate and characterize major intrahemispheric white matter tracts that are important in visuospatial processing. CSD-based tractography avoids a number of critical confounds that are associated with diffusion tensor tractography, and to our knowledge, this is the first time that this advanced diffusion tractography method has been used in autism research. Twenty-five participants with ASD and aged 25, intelligence quotient-matched controls completed a high angular resolution diffusion imaging scan. The inferior fronto-occipital fasciculus (IFOF) and arcuate fasciculus were isolated using CSD-based tractography. Quantitative diffusion measures of white matter microstructural organization were compared between groups and associated with visuospatial processing performance. Significant alteration of white matter organization was present in the right IFOF in individuals with ASD. In addition, poorer visuospatial processing was associated in individuals with ASD with disrupted white matter in the right IFOF. Using a novel, advanced tractography method to isolate major intrahemispheric white matter tracts in autism, this research has demonstrated that there are significant alterations in the microstructural organization of white matter in the right IFOF in ASD. This alteration was associated with poorer visuospatial processing performance in the ASD group. This study provides an insight into structural brain abnormalities that may influence atypical visuospatial processing in autism. PMID:23509018

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

    PubMed Central

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

    2013-01-01

    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

  20. Adaptive Filters Revisited :Adaptive Filters Revisited : RFI Mitigation in PulsarRFI Mitigation in Pulsar

    E-print Network

    Ellingson, Steven W.

    Adaptive Filters Revisited :Adaptive Filters Revisited : RFI Mitigation in PulsarRFI Mitigation in Pulsar ObservationsObservations M.Kesteven1, G.Hobbs1, R.Clement2,, B.Dawson1, R.Manchester1 , T.Uppal1/folding. We have started to quantify the RFI impact on the pulsar observations and timing. We continue

  1. Analysis of revisitations in online games Ruck Thawonmas a,

    E-print Network

    Chen, Sheng-Wei

    Analysis of revisitations in online games Ruck Thawonmas a, , Keisuke Yoshida a , Jing-Kai Lou b xxxx Keywords: Revisitation Online game Analysis Support Vector Machine Ward hierarchical clustering Shen Zhou Online World of Warcraft a b s t r a c t This paper analyzes revisitations in online games

  2. Pharmacy school survey standards revisited.

    PubMed

    Mészáros, Károly; Barnett, Mitchell J; Lenth, Russell V; Knapp, Katherine K

    2013-02-12

    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

  3. Revisiting Bohr's semiclassical quantum theory.

    PubMed

    Ben-Amotz, Dor

    2006-10-12

    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

  4. Cholesterol and vitamins: revisited study.

    PubMed

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

    2011-01-01

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

  5. Revisitation patterns in World Wide Web navigation

    Microsoft Academic Search

    Linda Tauscher; Saul Greenberg

    1997-01-01

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

  6. The Rotating Morse-Pekeris Oscillator Revisited

    ERIC Educational Resources Information Center

    Zuniga, Jose; Bastida, Adolfo; Requena, Alberto

    2008-01-01

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

  7. The Do-Calculus Revisited Judea Pearl

    E-print Network

    California at Los Angeles, University of

    The Do-Calculus Revisited Judea Pearl Keynote Lecture, August 17, 2012 UAI-2012 Conference and Pearl, 2006] and the graphi- cal criteria of [Tian and Shpitser, 2010] have laid this identification areas: mediation analysis [Pearl, 2012], trans- portability [Pearl and Bareinboim, 2011] and meta

  8. "Student Personnel: All Hail and Farewell!" Revisited.

    ERIC Educational Resources Information Center

    Bucci, Frank A.

    1993-01-01

    Revisits Crookston's (1976) article advocating to expunge term "student personnel," arguing that it is inappropriate and no longer descriptive of student affairs. Presents background of term to determine whether it continues to be used to identify chief student affairs officers and graduate programs that prepare sstudent affairs practitioners or…

  9. Ribaucour transformations revisited Armando V. Corro

    E-print Network

    Tenenblat, Keti

    Ribaucour transformations revisited Armando V. Corro Keti Tenenblat Abstract We present a revised definition of a Ribaucour transformation for submanifolds of space forms, with flat normal bundle, motivated- cise treatment of the geometric aspect of such transformations preserving lines of curvature and it can

  10. Nikos Tz. 1 AJM-games revisited

    E-print Network

    Nikos Tz. ­ 1 AJM-games revisited Nikos Tzevelekos GaLoP V ­ Paphos ­ 2010 #12;AJM vs. HO AJM vs. HO · The Mother of All Toy Languages · Full abstraction for PCF · Features of two game models: HO vs, Jagadeesan & Malacaria; · HO: Hyland & Ong and, indipendently, Nickau. #12;Full abstraction for PCF Nikos Tz

  11. Gate sizing by Lagrangian relaxation revisited

    Microsoft Academic Search

    Jia Wang; Debasish Das; Hai Zhou

    2007-01-01

    In this paper, we formulate the Generalized Convex Sizing (GCS) problem that unifies and generalizes the sizing problems. We revisit the approach to solve the sizing problem by Lagrangian relaxation, point out several misunderstandings in the previous works, and extend the approach to handle general convex delay functions in the GCS problems. We identify a class of proper GCS problems

  12. Gate sizing by lagrangian relaxation revisited

    Microsoft Academic Search

    Jia Wang; Debasish Das; Hai Zhou

    2007-01-01

    In this paper, we formulate the generalized convex sizing (GCS) problem that unifies and generalizes the sizing problems. We revisit the approach to solve the sizing problem by Lagrangian relaxation, point out several misunderstandings in the previous works, and extend the approach to handle general convex delay functions in the GCS problems. We identify a class of proper GCS problems

  13. Modeling skin permeation revisited Gabriel Wittum

    E-print Network

    Hackbusch, Wolfgang

    Modeling skin permeation revisited Gabriel Wittum Computing diffusion through human skin is usually diffusion through human skin using two and three dimensional models. First computations for this problem were made a decade ago, yielding new insight into permeation pathways through human skin, which were

  14. Making Meaning in Computers: Synthetic Ethology Revisited

    E-print Network

    MacLennan, Bruce

    Making Meaning in Computers: Synthetic Ethology Revisited Technical Report UT-CS-05-549 Bruce J.cs.utk.edu/~mclennan May 5, 2005 Revised November 1, 2006 Abstract This report describes synthetic ethology, a scientific to their environment. First we review the motivations for synthetic ethology as an experimental methodology and explain

  15. The Fermat factorization method revisited Robert Erra

    E-print Network

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

  16. Spectral analysis revisited with optimization techniques

    E-print Network

    Combettes, Patrick Louis

    dk, Signal x IMF d1 for K = 2 IMF d2 Trend a2 #12;Motivations Decomposition Spectral analysis 7Spectral analysis revisited with optimization techniques Nelly Pustelnik (joint work with P Italo-Fran¸cais, Sestri Levante 2014 #12;Motivations Decomposition Spectral analysis 2/24 Motivations

  17. Redemption Revisited: Doing Theology at Shawshank

    Microsoft Academic Search

    Christopher Deacy

    2006-01-01

    This article examines recent scholarly attempts to revisit the Christian theme of redemption by making various uses of Frank Darabont's 1994 film The Shawshank Redemption. While the appropriation of this film has generated much insightful theology, there has been an insufficient regard for the extent to which ‘redemption’ is a diverse and heterogeneous term which is not intrinsically transferable beyond

  18. Ant Foraging Revisited Liviu Alexandru Panait1

    E-print Network

    Luke, Sean

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

  19. Revisiting the argument from fetal potential

    Microsoft Academic Search

    Bertha Alvarez Manninen

    2007-01-01

    One of the most famous, and most derided, arguments against the morality of abortion is the argument from potential, which maintains that the fetus' potential to become a person and enjoy the valuable life common to persons, entails that its destruction is prima facie morally impermissible. In this paper, I will revisit and offer a defense of the argument from

  20. ORIGINAL ARTICLE Cytosolic potassium homeostasis revisited: 42

    E-print Network

    Britto, Dev T.

    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

  1. Revisiting the Definition of Homo Sapiens

    Microsoft Academic Search

    John D. Loike; Moshe David Tendler

    2002-01-01

    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

  2. Revisiting the Regenerative Possibilities of Ortiz

    ERIC Educational Resources Information Center

    Duques, Matthew

    2004-01-01

    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…

  3. Broadcast Flooding Revisited: Survivability and Latency

    E-print Network

    Riedi, Rudolf H.

    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

  4. Mutual Exclusion Revisited Boleslaw K. Szymanski

    E-print Network

    Varela, Carlos

    Mutual Exclusion Revisited Boleslaw K. Szymanski Computer Science Department Rensselaer Polytechnic Institute Troy, NY 12180 Abstract A family of four mutual exclusion algorithms is pre- sented. Its members vary from a simple three-bit linear wait mutual exclusion to the four-bit first-come first- served

  5. Revisiting the Skills Agenda: A Complicated Geography

    ERIC Educational Resources Information Center

    Saunders, Angharad

    2011-01-01

    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…

  6. Multi-modal MRI of mild traumatic brain injury

    PubMed Central

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

    2014-01-01

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

  7. Disconnection mechanism and regional cortical atrophy contribute to impaired processing of facial expressions and theory of mind in multiple sclerosis: a structural MRI study.

    PubMed

    Mike, Andrea; Strammer, Erzsebet; Aradi, Mihaly; Orsi, Gergely; Perlaki, Gabor; Hajnal, Andras; Sandor, Janos; Banati, Miklos; Illes, Eniko; Zaitsev, Alexander; Herold, Robert; Guttmann, Charles R G; Illes, Zsolt

    2013-01-01

    Successful socialization requires the ability of understanding of others' mental states. This ability called as mentalization (Theory of Mind) may become deficient and contribute to everyday life difficulties in multiple sclerosis. We aimed to explore the impact of brain pathology on mentalization performance in multiple sclerosis. Mentalization performance of 49 patients with multiple sclerosis was compared to 24 age- and gender matched healthy controls. T1- and T2-weighted three-dimensional brain MRI images were acquired at 3Tesla from patients with multiple sclerosis and 18 gender- and age matched healthy controls. We assessed overall brain cortical thickness in patients with multiple sclerosis and the scanned healthy controls, and measured the total and regional T1 and T2 white matter lesion volumes in patients with multiple sclerosis. Performances in tests of recognition of mental states and emotions from facial expressions and eye gazes correlated with both total T1-lesion load and regional T1-lesion load of association fiber tracts interconnecting cortical regions related to visual and emotion processing (genu and splenium of corpus callosum, right inferior longitudinal fasciculus, right inferior fronto-occipital fasciculus, uncinate fasciculus). Both of these tests showed correlations with specific cortical areas involved in emotion recognition from facial expressions (right and left fusiform face area, frontal eye filed), processing of emotions (right entorhinal cortex) and socially relevant information (left temporal pole). Thus, both disconnection mechanism due to white matter lesions and cortical thinning of specific brain areas may result in cognitive deficit in multiple sclerosis affecting emotion and mental state processing from facial expressions and contributing to everyday and social life difficulties of these patients. PMID:24349280

  8. Multi-modal MRI of mild traumatic brain injury.

    PubMed

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

    2015-01-01

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

  9. UNIVERSITY OF MANCHESTER Stability boundaries revisited -Runge-Kutta

    E-print Network

    Paul, Christopher A.H.

    UNIVERSITY OF MANCHESTER Stability boundaries revisited - Runge-Kutta methods for delay;Stability boundaries revisited - Runge-Kutta methods for delay differential equations C.A.H. Paul and C various Runge- Kutta methods, combined with continuous extensions, are applied with a fixed stepsize h

  10. Martin's maximum revisited: Woodin cardinals, forcing axioms, -logic, continued.....

    E-print Network

    Viale, Matteo

    Martin's maximum revisited: Woodin cardinals, forcing axioms, -logic, continued..... Matteo Viale Dipartimento di Matematica Universit`a di Torino 21 July 2011 Singapore M. Viale (Torino) Martin's maximum revisited 21 July 2011 Singapore 1 / 34 #12;....and partly repeated...... M. Viale (Torino) Martin's maximum

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

    E-print Network

    Owen, Art

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

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

    E-print Network

    Owen, Art

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

  13. Setting the revisit interval in primary care

    Microsoft Academic Search

    Lisa M. Schwartz; Steven Woloshin; John H. Wasson; Roger A. Renfrew; H. Gilbert Welch

    1999-01-01

    OBJECTIVE: Although longitudinal care constitutes the bulk of primary care, physicians receive little guidance on the fundamental question\\u000a of how to time follow-up visits. We sought to identify important predictors of the revisit interval and to describe the variability\\u000a in how physicians set these intervals when caring for patients with common medical conditions.\\u000a \\u000a \\u000a DESIGN: Cross-sectional survey of physicians performed at

  14. THE MATHEMATICAL FOUNDATIONS OF GAUGE THEORY REVISITED

    E-print Network

    Paris-Sud XI, Université de

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

  15. Correspondence - Dynamic leakage current compensation revisited.

    PubMed

    Schenk, Tony; Schroeder, Uwe; Mikolajick, Thomas

    2015-03-01

    The approach of dynamic leakage current compensation (DLCC) for leaky ferroelectrics is revisited. Meyer et al. introduced a calculus based on the transient currents recorded during a dynamic hysteresis measurement. Here, a complementary calculus based on polarization data is presented which eases data processing. The effect of the DLCC is exemplified and some practical limitations are given beyond what was presented in 2005. PMID:25768825

  16. T. W. Patzek, Fick's Diffusion Experiments Revisited, 6/22/06 1 Fick's Diffusion Experiments Revisited

    E-print Network

    Patzek, Tadeusz W.

    at Berkeley 591 Evans Hall Berkeley, CA 94720 Patzek@patzek.berkeley.edu Abstract In this paper, we revisit to medicine and it brings interesting insights into Fick's way of thinking about diffusion and osmosis, see) and (Bird 1960). For an exquisite and brief discussion of the various theories of diffusion developed over

  17. Structural correlates of facial emotion recognition deficits in Parkinson's disease patients.

    PubMed

    Baggio, H C; Segura, B; Ibarretxe-Bilbao, N; Valldeoriola, F; Marti, M J; Compta, Y; Tolosa, E; Junqué, C

    2012-07-01

    The ability to recognize facial emotion expressions, especially negative ones, is described to be impaired in Parkinson's disease (PD) patients. Previous neuroimaging work evaluating the neural substrate of facial emotion recognition (FER) in healthy and pathological subjects has mostly focused on functional changes. This study was designed to evaluate gray matter (GM) and white matter (WM) correlates of FER in a large sample of PD. Thirty-nine PD patients and 23 healthy controls (HC) were tested with the Ekman 60 test for FER and with magnetic resonance imaging. Effects of associated depressive symptoms were taken into account. In accordance with previous studies, PD patients performed significantly worse in recognizing sadness, anger and disgust. In PD patients, voxel-based morphometry analysis revealed areas of positive correlation between individual emotion recognition and GM volume: in the right orbitofrontal cortex, amygdala and postcentral gyrus and sadness identification; in the right occipital fusiform gyrus, ventral striatum and subgenual cortex and anger identification, and in the anterior cingulate cortex (ACC) and disgust identification. WM analysis through diffusion tensor imaging revealed significant positive correlations between fractional anisotropy levels in the frontal portion of the right inferior fronto-occipital fasciculus and the performance in the identification of sadness. These findings shed light on the structural neural bases of the deficits presented by PD patients in this skill. PMID:22640663

  18. White matter structure and symptom dimensions in obsessive-compulsive disorder.

    PubMed

    Koch, Kathrin; Wagner, Gerd; Schachtzabel, Claudia; Schultz, C Christoph; Straube, Thomas; Güllmar, Daniel; Reichenbach, Jürgen R; Peikert, Gregor; Sauer, Heinrich; Schlösser, Ralf G M

    2012-02-01

    There is evidence that the different symptom dimensions in obsessive-compulsive disorder (OCD) may be mediated by partially distinct neural systems. This DTI study investigated the relationship between symptom dimensions and white matter microstructure. Fractional anisotropy (FA), axial and radial diffusivity was analyzed in relation to the main OCD symptom dimensions. Symptom severity on the obsessing dimension was negatively correlated with FA in the corpus callosum and the cingulate bundle. Severity on the ordering dimension was negatively correlated with FA in, amongst others, the right inferior fronto-occipital fasciculus and the right optic radiation. All correlations were ascribable to alterations in radial diffusivity while there was no association between symptoms and axial diffusivity. Present results illustrate an association between alterations in visual processing tracts and ordering symptoms which are characterized by altered visual processing and increased attention towards irrelevant detail. They also indicate an association between obsessive thoughts and alterations in structures known to be relevant for cognitive control and inhibition. Hence, different symptom dimensions must be taken into account in order to disentangle the neurobiological underpinnings of OCD. PMID:22099866

  19. White matter integrity and vulnerability to Alzheimer's disease: Preliminary findings and future directions

    PubMed Central

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

    2011-01-01

    Neuroimaging biomarkers that precede cognitive decline have the potential to aid early diagnosis of Alzheimer's disease (AD). A body of diffusion tensor imaging (DTI) work has demonstrated declines in white matter (WM) microstructure in AD and its typical prodromal state, amnestic mild cognitive impairment. The present review summarizes recent evidence suggesting that WM integrity declines are present in individuals at high AD-risk, prior to cognitive decline. The available data suggest that AD-risk is associated with WM integrity declines in a subset of tracts showing decline in symptomatic AD. Specifically, AD-risk has been associated with WM integrity declines in tracts that connect grey matter structures associated with memory function. These tracts include parahippocampal WM, the cinglum, the inferior fronto-occipital fasciculus, and the splenium of the corpus callosum. Preliminary evidence suggests that some AD-risk declines are characterized by increases of radial diffusivity, raising the possibility that a myelin-related pathology may contribute to AD onset. These findings justify future research aimed at a more complete understanding of the neurobiological bases of DTI-based declines in AD. With continued refinement of imaging methods, DTI holds promise as a method to aid identification of presymptomatic AD. PMID:21803153

  20. Brain white matter microstructure in deficit and non-deficit subtypes of schizophrenia.

    PubMed

    Spalletta, Gianfranco; De Rossi, Pietro; Piras, Fabrizio; Iorio, Mariangela; Dacquino, Claudia; Scanu, Francesca; Girardi, Paolo; Caltagirone, Carlo; Kirkpatrick, Brian; Chiapponi, Chiara

    2015-03-30

    Dividing schizophrenia into its deficit (SZD) and nondeficit (SZND) subtypes may help to identify specific and more homogeneous pathophysiological characteristics. Our aim was to define a whole brain voxelwise map specifically characterizing white matter tracts of schizophrenia patients with and without the deficit syndrome. We compared microstructural diffusion-related parameters as measured by diffusion tensor imaging in 21 SZD patients, 21 SZND patients, and 21 healthy controls, age- and gender-matched. Results showed that fractional anisotropy was reduced in the right precentral area in SZND patients, and in the left corona radiata of the schizophrenia group as a whole. Axial diffusivity was reduced in the left postcentral area of SZD patients and in the left cerebellum of the whole schizophrenia group. Radial diffusivity was increased in the left forceps minor of SZD patients, in the left internal capsule of SZND patients, and in the right inferior fronto-occipital fasciculus in the whole schizophrenia group. Mean diffusivity was increased from healthy controls to SZD patients to SZND patients in the right occipital lobe. In conclusion, SZD patients are not simply at the extreme end of a severity continuum of white matter disruption. Rather, the SZD and SZND subtypes are associated with distinct and specific brain microstructural anomalies that are consistent with their peculiar psychopathological dimensions. PMID:25649975

  1. Orthorhombic Zr2Co11 phase revisited

    SciTech Connect

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

    2014-10-01

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

  2. Sloan Digital Sky Survey Photometric Calibration Revisited

    SciTech Connect

    Marriner, John; /Fermilab

    2012-06-29

    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.

  3. Revisiting Interval Graphs for Network Science

    E-print Network

    Loe, Chuan Wen

    2015-01-01

    The vertices of an interval graph represent intervals over a real line where overlapping intervals denote that their corresponding vertices are adjacent. This implies that the vertices are measurable by a metric and there exists a linear structure in the system. The generalization is an embedding of a graph onto a multi-dimensional Euclidean space and it was used by scientists to study the multi-relational complexity of ecology. However the research went out of fashion in the 1980s and was not revisited when Network Science recently expressed interests with multi-relational networks known as multiplexes. This paper studies interval graphs from the perspective of Network Science.

  4. 1969 revisited: reflections on Tomorrow's community physician.

    PubMed

    Donaldson, L J

    2001-10-01

    This lecture focuses on a paper that Jerry Morris published in the Lancet of Saturday 18 October 1969 entitled Tomorrow's Community Physician. It was a seminal paper in which a vision of the role and potential of a new breed of public health practitioner was set out. The themes raised in the original paper which examined population health and health service issues, are revisited, by assessing how things have changed, and in particular examining the extent to which the vision set out in the paper has become reality over the last 30 years. PMID:11689541

  5. Zebra Finch Sexual Differentiation: The Aromatization Hypothesis Revisited

    E-print Network

    Wade, Juli

    Zebra Finch Sexual Differentiation: The Aromatization Hypothesis Revisited JULI WADE Departments State University, East Lansing, Michigan 48824 KEY WORDS steroid hormone; estradiol; aromatase and sexual partner preference, however, are not associated with known sex differences in anatomy. In many

  6. A Revisiting of Scientific and Philosophical Perspectives on

    E-print Network

    Broschat, Shira Lynn

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

  7. Working through polytomies: Auklets revisited Elizabeth M. Humphries *, Kevin Winker

    E-print Network

    Winker, Kevin

    Working through polytomies: Auklets revisited Elizabeth M. Humphries *, Kevin Winker University multiple gene trees that have experienced incomplete lineage sort- ing (Carstens and Knowles, 2007; Liu and Pearl, 2007; Maddison and Knowles,

  8. Poisson Compound and Empirical Bayes Estimation, Revisited1 Lawrence Brown

    E-print Network

    Brown, Lawrence D.

    1 Poisson Compound and Empirical Bayes Estimation, Revisited1 Lawrence investigate a classical non-parametric Poisson empirical Bayes estimation problem,!( )= EG R ",!( )( ). The Bayes procedure is !G y( )= E " Y = y( ) (with the conditional

  9. Distance Perception in Immersive Virtual Environments, Revisited Victoria Interrante

    E-print Network

    Interrante, Victoria

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

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

    E-print Network

    Kreinovich, Vladik

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

  11. Landscape Planning and Conservation Biology: Systems Thinking Revisited

    E-print Network

    Nassauer, Joan Iverson

    Landscape Planning and Conservation Biology: Systems Thinking Revisited JOAN IVERSON NASSAUER Point: Science, Society, and Rising Culture. Both conservation biology and landscape planning are fields biolo- gists know that landscape planning processes affect biodi- versity on the ground, and practicing

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

    E-print Network

    Shaffer, H. Bradley

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

  13. Resonance on the web: web dynamics and revisitation patterns

    Microsoft Academic Search

    Eytan Adar; Jaime Teevan; Susan T. Dumais

    2009-01-01

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

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

    E-print Network

    Ziino, Jabe (Jabe S.)

    2011-01-01

    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 ...

  15. Anatomo-functional study of the temporo-parieto-occipital region: dissection, tractographic and brain mapping evidence from a neurosurgical perspective.

    PubMed

    De Benedictis, Alessandro; Duffau, Hugues; Paradiso, Beatrice; Grandi, Enrico; Balbi, Sergio; Granieri, Enrico; Colarusso, Enzo; Chioffi, Franco; Marras, Carlo Efisio; Sarubbo, Silvio

    2014-08-01

    The temporo-parieto-occipital (TPO) junction is a complex brain territory heavily involved in several high-level neurological functions, such as language, visuo-spatial recognition, writing, reading, symbol processing, calculation, self-processing, working memory, musical memory, and face and object recognition. Recent studies indicate that this area is covered by a thick network of white matter (WM) connections, which provide efficient and multimodal integration of information between both local and distant cortical nodes. It is important for neurosurgeons to have good knowledge of the three-dimensional subcortical organisation of this highly connected region to minimise post-operative permanent deficits. The aim of this dissection study was to highlight the subcortical functional anatomy from a topographical surgical perspective. Eight human hemispheres (four left, four right) obtained from four human cadavers were dissected according to Klingler's technique. Proceeding latero-medially, the authors describe the anatomical courses of and the relationships between the main pathways crossing the TPO. The results obtained from dissection were first integrated with diffusion tensor imaging reconstructions and subsequently with functional data obtained from three surgical cases, all resection of infiltrating glial tumours using direct electrical mapping in awake patients. The subcortical limits for performing safe lesionectomies within the TPO region are as follows: within the parietal region, the anterior horizontal part of the superior longitudinal fasciculus and, more deeply, the arcuate fasciculus; dorsally, the vertical projective thalamo-cortical fibres. For lesions located within the temporal and occipital lobes, the resection should be tailored according to the orientation of the horizontal associative pathways (the inferior fronto-occipital fascicle, inferior longitudinal fascicle and optic radiation). The relationships between the WM tracts and the ventricle system were also examined. These results indicate that a detailed anatomo-functional awareness of the WM architecture within the TPO area is mandatory when approaching intrinsic brain lesions to optimise surgical results and to minimise post-operative morbidity. PMID:24975421

  16. Microstructural white matter correlates of emotion recognition impairment in Amyotrophic Lateral Sclerosis.

    PubMed

    Crespi, Chiara; Cerami, Chiara; Dodich, Alessandra; Canessa, Nicola; Arpone, Marta; Iannaccone, Sandro; Corbo, Massimo; Lunetta, Christian; Scola, Elisa; Falini, Andrea; Cappa, Stefano F

    2014-04-01

    Amyotrophic Lateral Sclerosis (ALS) is associated in about half of the cases with behavioral and cognitive disorders, including impairments in socio-emotional processing, considered as key-features for the diagnosis of the behavioral variant of frontotemporal dementia (bv-FTD). The neurostructural bases of emotional deficits in ALS, however, still remain largely unexplored. Here we aim to assess emotion recognition in non-demented sporadic ALS patients compared with healthy controls, and to explore for the first time its microstructural white-matter correlates. Twenty-two subjects with either probable or definite diagnosis of ALS and 55 age-, gender-, and education-matched healthy controls were recruited in the study. All participants performed the Ekman 60-Faces Test, assessing the recognition of six basic emotions (i.e., anger, disgust, fear, sadness, surprise and happiness). A subgroup of subjects, comprising 19 patients and 20 healthy controls, also underwent a Diffusion Tensor Imaging scanning. Behavioral analysis highlighted a significant decline of emotion recognition skills in patients compared to controls, particularly affecting the identification of negative emotions. Moreover, the Diffusion Tensor Imaging analyses revealed a correlation between this impairment and the alteration of white-matter integrity along the right inferior longitudinal fasciculus and inferior fronto-occipital fasciculus. Our findings indicate the presence of an early emotion recognition deficit in non-demented sporadic ALS patients, associated with microstructural changes in ventral associative bundles connecting occipital, temporo-limbic and orbitofrontal regions in the right hemisphere. These changes may represent a frontotemporal-limbic microstructural marker of socio-emotional impairment in ALS. PMID:24534360

  17. Genetic Contributions to Changes of Fiber Tracts of Ventral Visual Stream in 22q11.2 Deletion Syndrome

    PubMed Central

    Kikinis, Zora; Makris, Nikos; Finn, Christine T.; Bouix, Sylvain; Lucia, Diandra; Coleman, Michael J.; Tworog-Dube, Erica; Kikinis, Ron; Kucherlapati, Raju; Shenton, Martha E.; Kubicki, Marek

    2013-01-01

    Patients with 22q11.2 deletion syndrome (22q11.2DS) represent a population at high risk for developing schizophrenia, as well as learning disabilities. Deficits in visuo-spatial memory are thought to underlie some of the cognitive disabilities. Neuronal substrates of visuo-spatial memory include the inferior fronto-occipital fasciculus (IFOF) and the inferior longitudinal fasciculus (ILF), two tracts that comprise the ventral visual stream. Diffusion Tensor Magnetic Resonance Imaging (DT-MRI) is an established method to evaluate white matter (WM) connections in vivo. DT-MRI scans of nine 22q11.2DS young adults and nine matched healthy subjects were acquired. Tractography of the IFOF and the ILF was performed. DT-MRI indices, including Fractional anisotropy (FA) (measure of WM changes), axial diffusivity (AD, measure of axonal changes) and radial diffusivity (RD, measure of myelin changes) of each of the tracts and each group were measured and compared. The 22q11.2DS group showed statistically significant reductions of FA in IFOF in the left hemisphere. Additionally, reductions of AD were found in the IFOF and the ILF in both hemispheres. These findings might be the consequence of axonal changes, which is possibly due to fewer, thinner, or less organized fibers. No changes in RD were detected in any of the tracts delineated, which is in contrast to findings in schizophrenia patients where increases in RD are believed to be indicative of demyelination. We conclude that reduced axonal changes may be key to understanding the underlying pathology of WM leading to the visuo-spatial phenotype in 22q11.2DS. PMID:23612843

  18. Longitudinal changes of structural connectivity in traumatic axonal injury

    PubMed Central

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

    2011-01-01

    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

  19. The Microstructural Status of the Corpus Callosum Is Associated with the Degree of Motor Function and Neurological Deficit in Stroke Patients

    PubMed Central

    Liang, Fanrong; Huang, Wenhua

    2015-01-01

    Human neuroimaging studies and animal models have suggested that white matter damage from ischemic stroke leads to the functional and structural reorganization of perilesional and remote brain regions. However, the quantitative relationship between the transcallosal tract integrity and clinical motor performance score after stroke remains unexplored. The current study employed a tract-based spatial statistics (TBSS) analysis on diffusion tensor imaging (DTI) to investigate the relationship between white matter diffusivity changes and the clinical scores in stroke patients. Probabilistic fiber tracking was also used to identify structural connectivity patterns in the patients. Thirteen ischemic stroke patients and fifteen healthy control subjects participated in this study. TBSS analyses showed that the corpus callosum (CC) and bilateral corticospinal tracts (CST) in the stroke patients exhibited significantly decreased fractional anisotropy and increased axial and radial diffusivity compared with those of the controls. Correlation analyses revealed that the motor and neurological deficit scores in the stroke patients were associated with the value of diffusivity indices in the CC. Compared with the healthy control group, probabilistic fiber tracking analyses revealed that significant changes in the inter-hemispheric fiber connections between the left and right motor cortex in the stroke patients were primarily located in the genu and body of the CC, left anterior thalamic radiation and inferior fronto-occipital fasciculus, bilateral CST, anterior/superior corona radiate, cingulum and superior longitudinal fasciculus, strongly suggesting that ischemic induces inter-hemispheric network disturbances and disrupts the white matter fibers connecting motor regions. In conclusion, the results of the present study show that DTI-derived measures in the CC can be used to predict the severity of motor skill and neurological deficit in stroke patients. Changes in structural connectivity pattern tracking between the left and right motor areas, particularly in the body of the CC, might reflect functional reorganization and behavioral deficit. PMID:25875333

  20. Structural and functional magnetic resonance imaging correlates of motor network dysfunction in primary progressive multiple sclerosis.

    PubMed

    Ceccarelli, Antonia; Rocca, Maria A; Valsasina, Paola; Rodegher, Mariaemma; Falini, Andrea; Comi, Giancarlo; Filippi, Massimo

    2010-04-01

    We combined functional magnetic resonance imaging (fMRI) and diffusion tensor tractography to investigate the functional and structural substrates of motor network dysfunction in patients with primary progressive multiple sclerosis (PPMS). In 15 right-handed PPMS patients and 15 age-matched healthy controls, we acquired diffusion tensor magnetic resonance imaging and fMRI during the performance of a simple motor task. Tractography was used to calculate diffusion tensor-derived measures of the corpus callosum, the corticospinal tract, the optic radiation, the fronto-occipital fasciculus, and the inferior longitudinal fasciculus. Analyses of fMRI activations and functional connectivity were performed using statistical parametric mapping (cluster threshold of P = 0.001, and extent cluster threshold of 10 voxels for comparison of activations; P < 0.05, family-wise error corrected for functional connectivity). As compared with controls, PPMS patients had more significant activations of the left postcentral gyrus, left secondary sensorimotor area, left parahippocampal gyrus, left cerebellum, right primary sensorimotor cortex (SMC), right basal ganglia, right insula, right cingulum, and cuneus bilaterally. As compared with PPMS patients, controls had increased functional connectivity between the left primary SMC and the ipsilateral inferior frontal gyrus. Conversely, PPMS patients showed increased functional connectivity between the left primary SMC and the right cuneus. Moderate correlations were found between functional activations and damage to the tracts studied (r-values between 0.82 and 0.84; P < 0.001). These results suggest that, as compared with healthy controls, PPMS patients show increased activations and abnormal functional connectivity measures in several areas of the sensorimotor network. Such changes are correlated with the structural damage to the white matter fiber bundles connecting these regions. PMID:20345920

  1. Abnormalities of cortical thickness, subcortical shapes, and white matter integrity in subcortical vascular cognitive impairment.

    PubMed

    Thong, Jamie Yu Jin; Du, Jia; Ratnarajah, Nagulan; Dong, Yanhong; Soon, Hock Wei; Saini, Monica; Tan, Ming Zhen; Ta, Anh Tuan; Chen, Christopher; Qiu, Anqi

    2014-05-01

    Subcortical vascular cognitive impairment (sVCI) is caused by lacunar infarcts or extensive and/or diffuse lesions in the white matter that may disrupt the white matter circuitry connecting cortical and subcortical regions and result in the degeneration of neurons in these regions. This study used structural magnetic resonance imaging (MRI) and high angular resolution diffusion imaging (HARDI) techniques to examine cortical thickness, subcortical shapes, and white matter integrity in mild vascular cognitive impairment no dementia (VCIND Mild) and moderate-to-severe VCI (MSVCI). Our study found that compared to controls (n = 25), VCIND Mild (n = 25), and MSVCI (n = 30) showed thinner cortex predominantly in the frontal cortex. The cortex in MSVCI was thinner in the parietal and lateral temporal cortices than that in VCIND Mild. Moreover, compared to controls, VCIND Mild and MSVCI showed smaller shapes (i.e., volume reduction) in the thalamus, putamen, and globus pallidus and ventricular enlargement. Finally, compared to controls, VCIND Mild, and MSVCI showed an increased mean diffusivity in the white matter, while decreased generalized fractional anisotropy was only found in the MSVCI subjects. The major axonal bundles involved in the white matter abnormalities were mainly toward the frontal regions, including the internal capsule/corona radiata, uncinate fasciculus, and anterior section of the inferior fronto-occipital fasciculus, and were anatomically connected to the affected cortical and subcortical structures. Our findings suggest that abnormalities in cortical, subcortical, and white matter morphology in sVCI occur in anatomically connected structures, and that abnormalities progress along a similar trajectory from the mild to moderate and severe conditions. PMID:23861356

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

    E-print Network

    Revisit Behavior in Social Media: The Phoenix-R Model and Discoveries Flavio Figueiredo1 , Jussara and mining popularity dynamics of social activity has important impli- cations for researchers, content creators and providers. We here investigate and model the effect of revisits on popularity. A revisit can

  3. Visser's massive graviton bimetric theory revisited

    SciTech Connect

    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

    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.

  4. Rotation and anisotropy of galaxies revisited

    E-print Network

    James Binney

    2005-04-18

    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.

  5. Perturbative Deformations of Conformal Field Theories Revisited

    NASA Astrophysics Data System (ADS)

    Kriz, Igor

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

  6. Revisiting a magneto-elastic strange attractor

    NASA Astrophysics Data System (ADS)

    Tam, Jee Ian; Holmes, Philip

    2014-03-01

    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.

  7. Higgs Portal Vector Dark Matter : Revisited

    E-print Network

    Seungwon Baek; P. Ko; Wan-Il Park; Eibun Senaha

    2013-04-15

    We revisit the Higgs portal vector dark matter model including a hidden sector Higgs field that generates the mass of the vector dark matter. The model becomes renormalizable and has two scalar bosons, the mixtures of the standard model (SM) Higgs and the hidden sector Higgs bosons. The strong bound from direct detection such as XENON100 is evaded due to the cancellation mechanism between the contributions from two scalar bosons. As a result, the model becomes still viable in large range of dark matter mass, contrary to some claims in the literature. The Higgs properties are also affected, the signal strengths for the Higgs boson search being universally suppressed relative to the SM value, which could be tested at the LHC in the future.

  8. Predator-prey interactions, resource depression and patch revisitation

    USGS Publications Warehouse

    Erwin, R.M.

    1989-01-01

    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.

  9. Charge symmetry breaking in $\\Lambda$ hypernuclei revisited

    E-print Network

    Gal, Avraham

    2015-01-01

    The large charge symmetry breaking (CSB) implied by the $\\Lambda$ binding energy difference $\\Delta B^{4}_{\\Lambda}(0^+_{\\rm g.s.})\\equiv B_{\\Lambda}(_{\\Lambda}^4$He)$-$$B_{\\Lambda}(_{\\Lambda}^4$H) = 0.35$\\pm$0.06 MeV of the $A=4$ mirror hypernuclei ground states, determined from emulsion studies, has defied theoretical attempts to reproduce it in terms of CSB in hyperon masses and in hyperon-nucleon interactions, including one pion exchange arising from $\\Lambda-\\Sigma^0$ mixing. Using a schematic strong-interaction $\\Lambda N\\leftrightarrow\\Sigma N$ coupling model developed by Akaishi and collaborators for $s$-shell $\\Lambda$ hypernuclei, we revisit the evaluation of CSB in the $A=4$ $\\Lambda$ hypernuclei and extend it to $p$-shell mirror $\\Lambda$ hypernuclei. The model yields values of $\\Delta B^{4}_{\\Lambda} (0^+_{\\rm g.s.})\\sim 0.25$ MeV. Smaller size and mostly negative $p$-shell binding energy differences are calculated for the $A=7-10$ mirror hypernuclei, in rough agreement with the few available dat...

  10. Revisiting Discrete Dark Matter Model:?_{13}\

    E-print Network

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

    2014-12-30

    We revisit the discrete dark matter model with $A_4$ flavor symmetry originally introduced by M.Hirsch {\\it et.al}. We show that radiative corrections can lead to non-zero $\\theta_{13}$ and 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 the thermal freeze-out explains observed dark matter abundance, TeV-scale right-handed neutrino and flavored scalar bosons are required. In such a case, 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 can be viable against currently existing constraints from collider, low energy experiments and cosmological observations.

  11. Spin-orbit evolution of Mercury revisited

    E-print Network

    Noyelles, Benoit; Makarov, Valeri; Efroimsky, Michael

    2013-01-01

    Mercury is a peculiar case, in that it is locked into the 3:2 spin-orbit resonance. Its rotation period, 58 days, is exactly two thirds of its orbital period. It is accepted that the eccentricity of Mercury (0.206) favours the trapping into this resonance. More controversial is how the capture took place. A recent study by Makarov has shown that entrapment into this resonance is certain if the eccentricity is larger than 0.2, provided that we use a realistic tidal model, based on the Darwin-Kaula expansion of the tidal torque, including both the elastic rebound and anelastic creep of solids. We here revisit the scenario of Mercury's capture into the supersynchronous spin-orbit resonances. The study is based on a realistic model of tidal friction in solids, that takes into account the rheology and the self-gravitation of the planet. Developed in Efroimsky, it was employed by Makarov et al. to determine the likely spin state of the planet GJ581d, with its eccentricity evolution taken into account. It was also u...

  12. Nursing knowledge, theory and method revisited.

    PubMed

    Booth, K; Kenrick, M; Woods, S

    1997-10-01

    With the approach of the 21st century, nursing is having to respond to diverse influences which are remoulding the professional landscape. Not least of these is the changing status of western economies which underpins a drive towards evidence-based practice and an increased emphasis on multidisciplinary approaches to health care delivery. Certainty in health care is now a thing of the past. Central to the way the nursing profession embraces the future is its underlying philosophy: that which articulates professional values and shapes practice, research, education and management. In a time of change it is therefore essential to revisit the philosophical framework which underpins nursing. The debate in nursing research and theory appears to have stressed the polarization of viewpoints. It may be the case that feminist writers, ethnographers, positivist researchers and nursing theorists, in defending their own points of view, diminish rather than enhance professional dialogue. This paper reviews the nature of this debate within nursing and considers the implications that a dichotomous position may have for knowledge, theory and research method within the current context of health care. It then suggests a philosophical framework which could be relevant and accessible across the whole spectrum of nursing activity. In so doing, the paper aims to contribute to the discussion around epistemology and method in a way which encompasses the diversity found within the broad church of nursing. PMID:9354995

  13. The Infrared Spectrum of CH_5^+ Revisited

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    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.

  14. Pair Production Constraints on Superluminal Neutrinos Revisited

    SciTech Connect

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

    2012-02-16

    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.

  15. Revisiting the phase diagram of hard ellipsoids.

    PubMed

    Odriozola, Gerardo

    2012-04-01

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

  16. Critical boundary sine-Gordon revisited

    SciTech Connect

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

    2006-12-15

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

  17. Structural sensitivity of biological models revisited.

    PubMed

    Cordoleani, Flora; Flora, Cordoleani; Nerini, David; David, Nerini; Gauduchon, Mathias; Mathias, Gauduchon; Morozov, Andrew; Andrew, Morozov; Poggiale, Jean-Christophe; Jean-Christophe, Poggiale

    2011-08-21

    Enhancing the predictive power of models in biology is a challenging issue. Among the major difficulties impeding model development and implementation are the sensitivity of outcomes to variations in model parameters, the problem of choosing of particular expressions for the parametrization of functional relations, and difficulties in validating models using laboratory data and/or field observations. In this paper, we revisit the phenomenon which is referred to as structural sensitivity of a model. Structural sensitivity arises as a result of the interplay between sensitivity of model outcomes to variations in parameters and sensitivity to the choice of model functions, and this can be somewhat of a bottleneck in improving the models predictive power. We provide a rigorous definition of structural sensitivity and we show how we can quantify the degree of sensitivity of a model based on the Hausdorff distance concept. We propose a simple semi-analytical test of structural sensitivity in an ODE modeling framework. Furthermore, we emphasize the importance of directly linking the variability of field/experimental data and model predictions, and we demonstrate a way of assessing the robustness of modeling predictions with respect to data sampling variability. As an insightful illustrative example, we test our sensitivity analysis methods on a chemostat predator-prey model, where we use laboratory data on the feeding of protozoa to parameterize the predator functional response. PMID:21641916

  18. Revisiting the argument from fetal potential.

    PubMed

    Manninen, Bertha Alvarez

    2007-01-01

    One of the most famous, and most derided, arguments against the morality of abortion is the argument from potential, which maintains that the fetus' potential to become a person and enjoy the valuable life common to persons, entails that its destruction is prima facie morally impermissible. In this paper, I will revisit and offer a defense of the argument from potential.First, I will criticize the classical arguments proffered against the importance of fetal potential, specifically the arguments put forth by philosophers Peter Singer and David Boonin, by carefully unpacking the claims made in these arguments and illustrating why they are flawed.Secondly, I will maintain that fetal potential is morally relevant when it comes to the morality of abortion, but that it must be accorded a proper place in the argument. This proper place, however, cannot be found until we first answer a very important and complex question: we must first address the issue of personal identity, and when the fetus becomes the type of being who is relevantly identical to a future person. I will illustrate why the question of fetal potential can only be meaningfully addressed after we have first answered the question of personal identity and how it relates to the human fetus. PMID:17509146

  19. Reducibility and contractivity of Runge-Kutta methods revisited1

    E-print Network

    Lang, Annika

    Reducibility and contractivity of Runge-Kutta methods revisited1 G. Dahlquist2 and R. Jeltsch, The Royal Institute of Technology, S-100 44 Stockholm 70, Sweden #12;Reducibility and contractivity of Runge-Kutta, Spijker and by Dahlquist and Jeltsch is given. A shifted Runge- Kutta scheme and a transplanted

  20. Cascade Encryption Revisited Peter Gazi1,2

    E-print Network

    Maurer, Ueli

    Cascade Encryption Revisited Peter Gazi1,2 and Ueli Maurer1 1 ETH Z¨urich, Switzerland Department of Computer Science Abstract. The security of cascade blockcipher encryption is an impor- tant and well-studied problem in theoretical cryptography with practical implications. It is well-known that double encryption

  1. Cascade Encryption Revisited Peter Gazi1,2

    E-print Network

    Cascade Encryption Revisited Peter Gazi1,2 and Ueli Maurer1 1 ETH Z¨urich, Switzerland Department of Computer Science gazi@dcs.fmph.uniba.sk Abstract. The security of cascade blockcipher encryption-known that double encryption improves the secu- rity only marginally, leaving triple encryption as the shortest

  2. REVISITING MALARIA: MOVING FROM CONTROL TO SUSTAINABLE ELIMINATION

    E-print Network

    Yehoshua, Kolodny

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

  3. Honors question 3: Complex numbers (revisited). Arithmetic of complex numbers

    E-print Network

    Leininger, Christopher J.

    Honors question 3: Complex numbers (revisited). Arithmetic of complex numbers Recall that the complex numbers are formally defined as C = {a + bi} where a and b can be any real numbers and i is treated as a variable (so we can identify the complex numbers with the set of linear polynomials with real

  4. Patterns of Revisitation in World Wide Web Navigation

    Microsoft Academic Search

    Linda Tauscher; Saul Greenberg

    1996-01-01

    In this paper, we report user's revisitation patterns to World Wide Web (WWW) pages, and u se the results to lay an empirical foundation towards the design of history mechanisms in Web browsers. Through history, a user can return qu ickly to a previously v isited p age, ostensibly reducing the c ognitive a nd phy sical overhead required to

  5. Tau-Coupling Revisited 103 When Is Behavioral Data

    E-print Network

    Jegelka, Stefanie

    Tau-Coupling Revisited 103 When Is Behavioral Data Evidence for a Control Theory? Tau is met in studies that claim to provide evidence for the tau- coupling theory. This theory proposes that moving targets are intercepted at a specified goal zone by maintaining a constant ratio between the tau

  6. Agent UML Class Diagrams Revisited Marc-Philippe Huget

    E-print Network

    Atkinson, Katie

    . In UML, objects which are the main element in the software are represented by class diagrams. SinceAgent UML Class Diagrams Revisited Marc-Philippe Huget Agent ART Group University of Liverpool and objects are not exactly the same, one can guess that the UML class diagram has to be changed

  7. A SIMPLE CARD GUESSING GAME REVISITED Arnold Knopfmacher

    E-print Network

    Prodinger, Helmut

    A SIMPLE CARD GUESSING GAME REVISITED Arnold Knopfmacher://www.wits.ac.za/helmut/index.htm Submitted: January 4, 2000; Accepted: March 3, 2000. Abstract. A deck of cards consisting of m red and n black cards is given.* * A guess is made as to the colour of the top card, after which

  8. Projected Tetrahedra Revisited: A Barycentric Formulation Applied to Digital

    E-print Network

    Cohen, Jonathan

    Projected Tetrahedra Revisited: A Barycentric Formulation Applied to Digital Radiograph tetrahedra, DRR, higher-order volumetric functions. æ 1 INTRODUCTION DRR (digitally reconstructed radiograph to the classic Projected Tetrahedra (PT) method, as presented by Shirley and Tuchman [3], and to its developments

  9. Threshold Concepts and Student Engagement: Revisiting Pedagogical Content Knowledge

    ERIC Educational Resources Information Center

    Zepke, Nick

    2013-01-01

    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…

  10. Information Theoretically Secure Multi Party Set Intersection Re-visited

    Microsoft Academic Search

    Arpita Patra; Ashish Choudhary; C. Pandu Rangan

    2009-01-01

    We re-visit the problem of secure multiparty set intersection in information theoretic settings. In (16), Li et.al have proposed a protocol for multiparty set intersection problem with n parties, that provides information theoretic security, when t < n 3 parties are corrupted by an active adversary having unbounded computing power. In (16), the authors claimed that their protocol takes six

  11. Artificial Intelligence 120 (2000) 2942 Optimal auctions revisited 6

    E-print Network

    Monderer, Dov

    2000-01-01

    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

  12. Of pungency, pain, and naked mole rats: chili peppers revisited

    E-print Network

    Borges, Renee M

    Clipboard Of pungency, pain, and naked mole rats: chili peppers revisited Capsaicinoids are unique to the chili pepper genus Capsicum within the plant family Solanaceae. The family is also known for species ranging from dry dehiscent capsules to fleshy drupes and berries. Botanically speaking, chili peppers

  13. Critical natural capital revisited: Ecological resilience and sustainable development

    Microsoft Academic Search

    Fridolin Brand

    2009-01-01

    The maintenance of critical natural capital is an important objective of sustainable development. Critical natural capital represents a multidimensional concept, as it mirrors the different frameworks of various scientific disciplines and social groups in valuing nature. This article revisits the concept of critical natural capital and examines its relation to the concept of ecological resilience. I propose that ecological resilience

  14. Revisiting Safe Strategies for Agent Modelling in Games Michael Bowling

    E-print Network

    Bowling, Michael

    Revisiting Safe Strategies for Agent Modelling in Games Michael Bowling Department of Computing;Acknowledgements Thanks to Sam Ganzfried for noting the circular argument in the original proof. References Peter McCracken and Michael Bowling. Safe strategies for agent modelling in games. In AAAI Fall Sympo- sium

  15. Revisiting Oligopolistic Reaction: Are Decisions on Foreign Direct

    E-print Network

    Boyer, Edmond

    Revisiting Oligopolistic Reaction: Are Decisions on Foreign Direct Investment Strategic Complements. Introduction Research on foreign direct investment (FDI) has long recognized two important motives for choosing-the-leader behavior. We find that rival foreign investment will make risk-neutral firms less inclined to move abroad

  16. Hotelling Revisited: Oil Prices and Endogenous Technological Progress1

    E-print Network

    Lin, C.-Y. Cynthia

    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

  17. The Polarized Structure Function g_2: A Lattice Study Revisited

    E-print Network

    M. Göckeler; R. Horsley; W. Kürzinger; H. Oelrich; P. Rakow; G. Schierholz

    1999-09-05

    A recent lattice calculation of the spin-dependent structure function g_2 is revisited. It has been recognized that the twist-three operator, which gives rise to d_2, mixes non-perturbatively with operators of lower dimensions under renormalization. This changes the results substantially.

  18. Montgomery Modular Multiplication on ARM-NEON Revisited

    E-print Network

    Montgomery Modular Multiplication on ARM-NEON Revisited Hwajeong Seo1 , Zhe Liu2 , Johann GroÃ?sch NEON) has initiated a massive body of research on vector-parallel implementations of Montgomery modular modular multiplication on ARM-NEON platforms. Detailed benchmarking results obtained on an ARM Cortex-A9

  19. Orientation Distance Graphs Revisited Wayne Goddard, Kiran Kanakadandi

    E-print Network

    Goddard, Wayne

    Orientation Distance Graphs Revisited Wayne Goddard, Kiran Kanakadandi Dept of Computer Science, Clemson University Abstract The orientation distance graph Do(G) of a graph G is defined as the graph whose vertex set is the pair-wise non-isomorphic orientations of G, and two orientations are adjacent

  20. Revisiting the Equivalence Problem for Finite Multitape Automata

    E-print Network

    Worrell, James

    Revisiting the Equivalence Problem for Finite Multitape Automata James Worrell Department on which they differ. 1 Introduction One-way multitape finite automata were introduced in the seminal 1959 the conjecture that the equivalence problem is decidable for general multitape deterministic finite-state

  1. The Fermat factorization method revisited Robert Erra # Christophe Grenier +

    E-print Network

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

  2. Re-Visiting Health Informatics What is Health Informatics?

    E-print Network

    Abidi, Syed Sibte Raza

    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

  3. NOTES AND COMMENTS Revisiting powdered sugar for varroa control on

    E-print Network

    Delaplane, Keith S.

    NOTES AND COMMENTS Revisiting powdered sugar for varroa control on honey bees (Apis mellifera L, accepted for publication 1 September 2012. Keywords: Varroa destructor, IPM, powdered sugar, dusts Journal sugar has been examined as a remedial control for Varroa destructor Anderson and Trueman (varroa). Two

  4. January 2013 BEE CULTURE 23 Revisiting Powdered Sugar For

    E-print Network

    Delaplane, Keith S.

    January 2013 BEE CULTURE 23 Revisiting Powdered Sugar For Varroa Control On Honey Bees (Apis dust bees with powder sugar as a means of removing mites. Dusting with powder sugar was also gaining conducted a study which examined the efficacy of powder sugar and found it did not help in controlling

  5. DNA Compression Challenge Revisited: a Dynamic Programming Approach

    E-print Network

    Lonardi, Stefano

    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

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

    ERIC Educational Resources Information Center

    Ushomirsky, Natasha

    2011-01-01

    "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…

  7. Revisiting the Trust Effect in Urban Elementary Schools

    ERIC Educational Resources Information Center

    Adams, Curt M.; Forsyth, Patrick B.

    2013-01-01

    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…

  8. Pockets of Participation: Revisiting Child-Centred Participation Research

    ERIC Educational Resources Information Center

    Franks, Myfanwy

    2011-01-01

    This article revisits the theme of the clash of interests and power relations at work in participatory research which is prescribed from above. It offers a possible route toward solving conflict between adult-led research carried out by young researchers, funding requirements and organisational constraints. The article explores issues of…

  9. The Importance of Being a Complement: CED Effects Revisited

    ERIC Educational Resources Information Center

    Jurka, Johannes

    2010-01-01

    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,…

  10. Back to the Future: Revisiting IPv6 Privacy Extensions

    E-print Network

    Van Oorschot, Paul

    Back to the Future: Revisiting IPv6 Privacy Extensions David Barrera, Glenn Wurster and P. C. van in current IPv6 privacy extensions and propose improvements that significantly enhance both the flexibility and functionality, to protect a client from being tracked as it moves between different IPv6 networks

  11. A Multi-Level Model of Moral Functioning Revisited

    ERIC Educational Resources Information Center

    Reed, Don Collins

    2009-01-01

    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…

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

    E-print Network

    Johnson, Robert E.

    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

  13. Revisiting the Uniqueness of Simple Demographics in the US Population

    E-print Network

    Golle, Philippe

    precisely the degree of privacy of in- dividuals on a scale that goes from uniquely identi- fiable to kRevisiting the Uniqueness of Simple Demographics in the US Population Philippe Golle Palo Alto% of the US population can be uniquely identified by gen- der, ZIP code and full date of birth. This short

  14. Ant Foraging Revisited Liviu A. Panait and Sean Luke

    E-print Network

    George Mason University

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

  15. Ant Foraging Revisited Liviu A. Panait and Sean Luke

    E-print Network

    Turk, Greg

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

  16. Revisiting the Role of Organizational Effectiveness in Educational Evaluation.

    ERIC Educational Resources Information Center

    Lotto, Linda S.

    Organizational effectiveness ought to play a role in educational evaluation, and the development of alternative perspectives for viewing organizations could be a starting point for revisiting organizational evaluation in education. Five possible perspectives and criteria for evaluating organizations have been developed. If an organization is…

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

    E-print Network

    Kreinovich, Vladik

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

  18. Revisiting Methodological Issues in Transcript Analysis: Negotiated Coding and Reliability

    ERIC Educational Resources Information Center

    Garrison, D. R.; Cleveland-Innes, M.; Koole, Marguerite; Kappelman, James

    2006-01-01

    Transcript analysis is an important methodology to study asynchronous online educational discourse. The purpose of this study is to revisit reliability and validity issues associated with transcript analysis. The goal is to provide researchers with guidance in coding transcripts. For validity reasons, it is suggested that the first step is to…

  19. Revisiting the Role of Communication in Adolescent Intimate Partner Violence

    ERIC Educational Resources Information Center

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

    2012-01-01

    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, &…

  20. Phenomenology of $n$-${\\bar n}$ Oscillations Revisited

    E-print Network

    S. Gardner; E. Jafari

    2015-02-05

    We revisit the phenomenology of $n$-${\\bar n}$ oscillations in the presence of external magnetic fields, highlighting the role of spin. We show, contrary to long-held belief, that the $n$-${\\bar n}$ transition rate need not be suppressed, opening new opportunities for its empirical study.

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

    E-print Network

    Aslin, Richard N.

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

  2. Pedomorphosis revisited: thyroid hormone receptors are functional in Necturus maculosus

    E-print Network

    Denver, Robert J.

    Pedomorphosis revisited: thyroid hormone receptors are functional in Necturus maculosus Rachid Safi metamorphosis. Thyroid hormone induces tissue transformation in metamorphosing species and this action is mediated by nuclear thyroid hormone (TH) receptors (TRs). The absence of metamorphosis in Necturus has been

  3. Magnetic Braking Revisited: Activities for the Undergraduate Laboratory

    ERIC Educational Resources Information Center

    Ireson, Gren; Twidle, John

    2008-01-01

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

  4. Prediction of Prokaryotic Transcription Units from Microarray Data Revisited

    E-print Network

    Hochreiter, Sepp

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

  5. The angular momentum of baryons and dark matter halos revisited

    Microsoft Academic Search

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

    2011-01-01

    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

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

    E-print Network

    Bernhard Rothenstein; Corina Nafornita

    2004-03-26

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

  7. Friction versus dilation revisited: Insights from theoretical and numerical models

    E-print Network

    Einat, Aharonov

    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

  8. Photochemical -cleavage of ketones: revisiting acetone Yehuda Haas

    E-print Network

    Haas, Yehuda

    Photochemical -cleavage of ketones: revisiting acetone Yehuda Haas Department of Physical Chemistry on the web 30th September 2003 The photochemical -cleavage of acetone is analyzed in view of recent results -cleavage to form the triplet radical pair CH3 CH3CO . Direct reaction from the S1 is negligible

  9. The coordinate coherent states approach revisited

    SciTech Connect

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

    2013-02-15

    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.

  10. Autosomal recessive cutis laxa syndrome revisited

    PubMed Central

    Morava, Éva; Guillard, Maïlys; Lefeber, Dirk J; Wevers, Ron A

    2009-01-01

    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

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

    PubMed Central

    2012-01-01

    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

  12. Some Operator Bounds Employing Complex Interpolation Revisited

    E-print Network

    Fritz Gesztesy; Yuri Latushkin; Fedor Sukochev; Yuri Tomilov

    2014-05-07

    We revisit and extend known bounds on operator-valued functions of the type $$ T_1^{-z} S T_2^{-1+z}, \\quad z \\in \\ol \\Sigma = \\{z\\in\\bbC\\,|\\, \\Re(z) \\in [0,1]\\}, $$ under various hypotheses on the linear operators $S$ and $T_j$, $j=1,2$. We particularly single out the case of self-adjoint and sectorial operators $T_j$ in some separable complex Hilbert space $\\cH_j$, $j=1,2$, and suppose that $S$ (resp., $S^*$) is a densely defined closed operator mapping $\\dom(S) \\subseteq \\cH_1$ into $\\cH_2$ (resp., $\\dom(S^*) \\subseteq \\cH_2$ into $\\cH_1$), relatively bounded with respect to $T_1$ (resp., $T_2^*$). Using complex interpolation methods, a generalized polar decomposition for $S$, and Heinz's inequality, the bounds we establish lead to inequalities of the following type, \\begin{align*} & \\big\\|\\ol{T_2^{-x}ST_1^{-1+x}}\\big\\|_{\\cB(\\cH_1,\\cH_2)} \\leq N_1 N_2 e^{(\\theta_1 + \\theta_2) [x(1-x)]^{1/2}} \\\\ & \\quad \\times \\big\\|ST_1^{-1}\\big\\|_{\\cB(\\cH_1,\\cH_2)}^{1-x} \\, \\big\\|S^*(T_2^*)^{-1}\\big\\|_{\\cB(\\cH_2,\\cH_1)}^{x}, \\quad x \\in [0,1], \\end{align*} assuming that $T_j$ have bounded imaginary powers, that is, for some $N_j\\ge 1$ and $\\theta_j \\ge 0,$ $$ \\big\\|T_j^{is}\\big\\|_{\\cB(\\cH)} \\leq N_j e^{\\theta_j |s|}, \\quad s \\in \\bbR, \\; j=1,2. $$ We also derive analogous bounds with $\\cB(\\cH_1,\\cH_2)$ replaced by trace ideals, $\\cB_p(\\cH_1, \\cH_2)$, $p \\in [1,\\infty)$. The methods employed are elementary, predominantly relying on Hadamard's three-lines theorem and Heinz's inequality.

  13. Reading Impairment in a Patient with Missing Arcuate Fasciculus

    ERIC Educational Resources Information Center

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

    2009-01-01

    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…

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

    E-print Network

    Obata, Nobuaki

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

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

    E-print Network

    IODINE IN THE ENVIRONMENT REVISITED. AN EVALUATION OF THE CHEMICAL- AND PHYSICO CHEMICAL PROCESSES-M-2791 IODINE IN THE ENVIRONMENT REVISITED. AN EVALUATION OF THE CHEMICAL- AND PHYSICO CHEMICAL PROCESSES POSSIBLY CONTROLLING THE MIGRATION BEHAVIOUR OF IODINE IN THE TERRESTRIAL ENVIRONMENT. Jesper V

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

    E-print Network

    Paris-Sud XI, Université de

    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[18], incidentally reaching infinite (continuous) domains. The NoGo game is similar to Go

  17. Brane inflation revisited after WMAP five-year results

    Microsoft Academic Search

    Yin-Zhe Ma; Xin Zhang

    2009-01-01

    In this paper, we revisit brane inflation models with the WMAP five-year results. The WMAP five-year data favor a red-tilted power spectrum of primordial fluctuations at the level of two standard deviations, which is the same as the WMAP three-year result qualitatively, but quantitatively the spectral index is slightly greater than the three-year value. This result can bring impacts on

  18. Indoor air and human health revisited: A recent IAQ symposium

    SciTech Connect

    Gammage, R.B.

    1994-12-31

    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.

  19. Topological Twisted Sigma Model with H-flux Revisited

    SciTech Connect

    Chuang, Wu-yen

    2006-08-18

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

  20. White matter organization and neurocognitive performance variability in schizophrenia

    PubMed Central

    Roalf, David R.; Ruparel, Kosha; Verma, Ragini; Elliott, Mark A.; Gur, Raquel E.; Gur, Ruben C.

    2012-01-01

    Background White matter alterations in schizophrenia are associated with deficits in neurocognitive performance. Recently, across task within-individual variability (WIV) has emerged as a useful construct for assessing the profile in cognitive performance in schizophrenia. However, the neural basis of WIV has not been studied in patients with schizophrenia. Methods Twenty-five patients with schizophrenia (SZ) and 27 healthy comparison subjects (HC) performed a computerized neurocognitive battery (CNB) and underwent diffusion tensor imaging (DTI). WIV for performance accuracy and speed on the CNB was calculated across-tasks. Voxel-wise group comparisons of white matter fractional anisotropy (FA) were performed using tract-based spatial statistics (TBSS). The relationship between accuracy and speed WIV on the CNB and white matter FA was examined within the regions that differentiated patients and healthy comparison subjects. Results SZ had higher WIV for performance accuracy and speed as compared to HC. FA in SZ compared to HC was reduced in bilateral frontal, temporal and occipital white matter including a large portion of the corpus callosum. In white matter regions that differed between patients and comparison subjects, higher FA in the left cingulum bundle and left fronto-occipital fasciculus were associated with lower CNB speed WIV for HC, but not SZ. Accuracy WIV was not associated with differences in white matter FA between SZ and HC. Conclusions We provide evidence that WIV is greater in patients with SZ and that this greater within-individual variability in performance in patients is associated with disruptions of WM integrity in specific brain regions. PMID:23148898

  1. IN VIVO STUDY OF CEREBRAL WHITE MATTER IN THE DOG USING DIFFUSION TENSOR TRACTOGRAPHY.

    PubMed

    Anaya García, Mitzi Sarahí; Hernández Anaya, Jael Sarahí; Marrufo Meléndez, Oscar; Velázquez Ramírez, José Luis; Palacios Aguiar, Ricardo

    2014-10-01

    Conventional magnetic resonance imaging (MRI) allows investigators and clinicians to observe the anatomy and injuries of the cerebral white matter (CWM) in dogs. However, dynamic images based on the diffusion tensor (DT) technique are required to assess fiber tract integrity of the CWM. Diffusion tensor tractography (DTT) produces a three-dimensional representation in which data are displayed on a colored map obtained from the anisotropy of water molecules in the CWM tracts. Fractional anisotropy (FA) is a value that measures changes in water diffusion, which can occur if the CWM tracts are displaced, disrupted, or infiltrated. The goal of this study was to determine the feasibility of DTT for in vivo examination of the normal appearance of CWM in dogs through visual and quantitative analysis of the most representative CWM tracts. Nine tractographies were performed on healthy dogs using a 3T MRI scanner. T1- and T2-weighted images and DTI were acquired at different planes. Using DTT, three-dimensional reconstructions were obtained. Fractional ansisotropy and apparent diffusion coefficient (ADC) values of the right and left corticospinal tracts, corpus callosum, cingulum, and right and left fronto-occipital fasciculus were determined. Tract reconstructions were similar in 8/9 healthy dogs. Values for FA and ADC were similar in all the dogs. In one dog, tract reconstructions were inhomogeneous; these were displaced because it had larger lateral ventricles. Findings indicated that DTT is a feasible technique for in vivo study of CWM in dogs and that it complements information from conventional MRI. PMID:25288360

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

    PubMed Central

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

    2010-01-01

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

  3. White Matter Disruptions in Adolescents Exposed to Childhood Maltreatment and Vulnerability to Psychopathology

    PubMed Central

    Huang, Hao; Gundapuneedi, Tejasvi; Rao, Uma

    2012-01-01

    Childhood maltreatment has been known to produce long-lasting impairments in behavioral, cognitive and social functioning, but their underlying mechanisms are not well-understood. A better understanding of their underlying mechanisms will aid in developing effective preventive interventions. Nineteen adolescent volunteers with no personal history of a psychiatric illness, but who were exposed to maltreatment during childhood, and 13 adolescent volunteers with no personal or family history of a psychiatric disorder (controls) underwent diffusion tensor imaging (DTI) studies. The participants were then followed longitudinally at 6-month intervals for up to 5 years to determine the onset of mood and substance use disorders. The associations among fractional anisotropy (FA) values obtained from the DTI scans at baseline and psychopathology at follow-up were examined. At baseline, adolescents exposed to childhood maltreatment had significantly lower FA values in the left and right superior longitudinal fasciculi, right cingulum bundle projecting to the hippocampus, left inferior fronto-occipital fasciculus, and splenium of the corpus callosum compared with controls. Adolescents who developed major depressive disorder at follow-up had significantly lower FA values in the superior longitudinal fasciculi and the right cingulum-hippocampal projection compared with their counterparts who did not develop the illness. Adolescents who developed substance use disorder during follow-up had significantly lower FA values in the right cingulum-hippocampal projection than their counterparts without the disorder. These preliminary results suggest that white matter disruptions observed in adolescents exposed to childhood maltreatment may be associated with increased vulnerability to psychopathology, specifically depressive and substance use disorders. PMID:22850736

  4. Shared genetic variance between obesity and white matter integrity in Mexican Americans

    PubMed Central

    Spieker, Elena A.; Kochunov, Peter; Rowland, Laura M.; Sprooten, Emma; Winkler, Anderson M.; Olvera, Rene L.; Almasy, Laura; Duggirala, Ravi; Fox, Peter T.; Blangero, John; Glahn, David C.; Curran, Joanne E.

    2015-01-01

    Obesity is a chronic metabolic disorder that may also lead to reduced white matter integrity, potentially due to shared genetic risk factors. Genetic correlation analyses were conducted in a large cohort of Mexican American families in San Antonio (N = 761, 58% females, ages 18–81 years; 41.3 ± 14.5) from the Genetics of Brain Structure and Function Study. Shared genetic variance was calculated between measures of adiposity [(body mass index (BMI; kg/m2) and waist circumference (WC; in)] and whole-brain and regional measurements of cerebral white matter integrity (fractional anisotropy). Whole-brain average and regional fractional anisotropy values for 10 major white matter tracts were calculated from high angular resolution diffusion tensor imaging data (DTI; 1.7 × 1.7 × 3 mm; 55 directions). Additive genetic factors explained intersubject variance in BMI (heritability, h2 = 0.58), WC (h2 = 0.57), and FA (h2 = 0.49). FA shared significant portions of genetic variance with BMI in the genu (?G = ?0.25), body (?G = ?0.30), and splenium (?G = ?0.26) of the corpus callosum, internal capsule (?G = ?0.29), and thalamic radiation (?G = ?0.31) (all p's = 0.043). The strongest evidence of shared variance was between BMI/WC and FA in the superior fronto-occipital fasciculus (?G = ?0.39, p = 0.020; ?G = ?0.39, p = 0.030), which highlights region-specific variation in neural correlates of obesity. This may suggest that increase in obesity and reduced white matter integrity share common genetic risk factors.

  5. Genetics of brain fiber architecture and intellectual performance.

    PubMed

    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

    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

  6. Diffuse alterations in grey and white matter associated with cognitive impairment in Shwachman–Diamond syndrome: Evidence from a multimodal approach

    PubMed Central

    Perobelli, Sandra; Alessandrini, Franco; Zoccatelli, Giada; Nicolis, Elena; Beltramello, Alberto; Assael, Baroukh M.; Cipolli, Marco

    2015-01-01

    Shwachman–Diamond syndrome is a rare recessive genetic disease caused by mutations in SBDS gene, at chromosome 7q11. Phenotypically, the syndrome is characterized by exocrine pancreatic insufficiency, bone marrow dysfunction, skeletal dysplasia and variable cognitive impairments. Structural brain abnormalities (smaller head circumference and decreased brain volume) have also been reported. No correlation studies between brain abnormalities and neuropsychological features have yet been performed. In this study we investigate neuroanatomical findings, neurofunctional pathways and cognitive functioning of Shwachman–Diamond syndrome subjects compared with healthy controls. To be eligible for inclusion, participants were required to have known SBDS mutations on both alleles, no history of cranial trauma or any standard contraindication to magnetic resonance imaging. Appropriate tests were used to assess cognitive functions. The static images were acquired on a 3 × 0 T magnetic resonance scanner and blood oxygen level-dependent functional magnetic resonance imaging data were collected both during the execution of the Stroop task and at rest. Diffusion tensor imaging was used to assess brain white matter. The Tract-based Spatial Statistics package and probabilistic tractography were used to characterize white matter pathways. Nine participants (5 males), half of all the subjects aged 9–19 years included in the Italian Shwachman–Diamond Syndrome Registry, were evaluated and compared with nine healthy subjects, matched for sex and age. The patients performed less well than norms and controls on cognitive tasks (p = 0.0002). Overall, cortical thickness was greater in the patients, both in the left (+10%) and in the right (+15%) hemisphere, significantly differently increased in the temporal (left and right, p = 0.04), and right parietal (p = 0.03) lobes and in Brodmann area 44 (p = 0.04) of the right frontal lobe. The greatest increases were observed in the left limbic-anterior cingulate cortex (?43%, p < 0.0004). Only in Broca's area in the left hemisphere did the patients show a thinner cortical thickness than that of controls (p = 0.01). Diffusion tensor imaging showed large, significant difference increases in both fractional anisotropy (+37%, p < 0.0001) and mean diffusivity (+35%, p < 0.005); the Tract-based Spatial Statistics analysis identified six abnormal clusters of white matter fibres in the fronto-callosal, right fronto-external capsulae, left fronto-parietal, right pontine, temporo-mesial and left anterior–medial–temporal regions. Brain areas activated during the Stroop task and those active during the resting state, are different, fewer and smaller in patients and correlate with worse performance (p = 0.002). Cognitive impairment in Shwachman–Diamond syndrome subjects is associated with diffuse brain anomalies in the grey matter (verbal skills with BA44 and BA20 in the right hemisphere; perceptual skills with BA5, 37, 20, 21, 42 in the left hemisphere) and white matter connectivity (verbal skills with alterations in the fronto-occipital fasciculus and with the inferior-longitudinal fasciculus; perceptual skills with the arcuate fasciculus, limbic and ponto-cerebellar fasciculus; memory skills with the arcuate fasciculus; executive functions with the anterior cingulated and arcuate fasciculus). PMID:25844324

  7. Non linear evolution: revisiting the solution in the saturation region

    E-print Network

    Carlos Contreras; Eugene Levin; Rodrigo Meneses

    2014-06-04

    In this paper we revisit the problem of the solution to Balitsky-Kovchegov equation deeply in the saturation domain. We find that solution has the form of Levin-Tuchin solution but it depends on variable $\\bar{z} = \\ln(r^2 Q^2_s) + \\mbox{Const}$ and the value of $\\mbox{Const}$ is calculated in this paper. We propose the solution for full BFKL kernel at large $z$ in the entire kinematic region that satisfies the McLerram-Venugopalan initial condition

  8. Massless Axions: the Callan-Harvey effect revisited

    NASA Astrophysics Data System (ADS)

    Kikuchi, Toru; Tanaka, Akihiro

    2013-03-01

    Axion-like degrees of freedom appear in the low energy physics of various condensed matter systems, which range from quantum spin systems and superconductors to topological insulators and their variants. When topological defects such as domain walls and vortices are formed by the axion fields, their responses to external fields are dominated by the current inflow from the surrounding bulk (Callan-Harvey effect). However, a dual reformulation due to Izquierdo-Townsend is known to present a controversy regarding the existence of this inflow in the case when axions are massless, and can have important consequences. We revisit this problem and discuss its possible relevance to condensed matters.

  9. ArmstrongMcGehee mechanism revisited: Competitive exclusion and coexistence of nonlinear consumers

    E-print Network

    Fussman, Gregor

    theoretical work has attempted to reconcile the competitive exclusion principle with naturally observedArmstrong­McGehee mechanism revisited: Competitive exclusion and coexistence of nonlinear consumers between competing consumers and their ability to avoid competitive exclusion through temporal resource

  10. INTERPERSONAL RELATIONS AND GROUP PROCESSES Sex Differences in Mate Preferences Revisited: Do People Know What

    E-print Network

    Reber, Paul J.

    INTERPERSONAL RELATIONS AND GROUP PROCESSES Sex Differences in Mate Preferences Revisited: Do-up procedures. Replicating previous research, participants exhibited traditional sex differences when stating, data revealed no sex differences in the associations between participants' romantic interest in real

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

    E-print Network

    Boyer, Edmond

    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

  12. Calendar of Events Machiavelli Revisited: New Approaches to his Political Theory

    E-print Network

    Qian, Ning

    1 Calendar of Events Machiavelli Revisited: New Approaches to his Political Theory Conference Jean Nicod - EHESS, Paris and Visiting Professor of Politics and Law, New York University. "Machiavelli Professor of Philosophy, University of Southern California "Machiavelli at Our Table: Philosophical

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    E-print Network

    Chaudhuri, Sanjay

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

  15. Edge Disjoint Paths Revisited \\Lambda Chandra Chekuri y Sanjeev Khanna z

    E-print Network

    Chekuri, Chandra

    Edge Disjoint Paths Revisited \\Lambda Chandra Chekuri y Sanjeev Khanna z Corresponding Author: Sanjeev Khanna 574 Levine Hall Dept. of CIS 3330 Walnut Street University of Pennsylvania Philadelphia, PA

  16. A parcel of muddling muckworms’: revisiting Habermas and the Early Modern English coffee-houses 

    E-print Network

    Laurier, Eric; Philo, Chris

    2007-01-01

    In the context of a research project concerned with contemporary cafés, one in which coffee-shops have loomed large, it has been appropriate to revisit Habermas’s famous 1962/1989 work on the transformation of the ‘public ...

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

    E-print Network

    Paris-Sud XI, Université de

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

  18. The contact of elastic regular wavy surfaces revisited

    E-print Network

    Vladislav A. Yastrebov; Guillaume Anciaux Jean-Francois Molinari

    2014-09-05

    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.

  19. Evidence based practice: decreasing psychiatric revisits to the emergency department.

    PubMed

    Adams, Priscilla; Nielson, Heather

    2012-08-01

    Inpatient psychiatric settings anticipate changes in reimbursement that will link payment rates to objective quality measures. Readmission rates are expected to be one of the quality measures. Inpatient areas are undertaking initiatives to decrease readmission rates in preparation for this change. The emphasis on avoiding readmission could cause an increase in emergency room revisit rates by psychiatric patients. In preparation for this potential impact, the mental health emergency service within the Emergency Department of a not-for-profit community based hospital implemented a proactive process improvement plan. The plan's goal was to insure that all patients' care was provided according to a defined standardize best practice process. Steps of the plan focused on (1) improving treatment providers' communications across the continuum of care, (2) enhancing communication between the mental health emergency department nurses and the on-call psychiatrists, (3) developing on-line decisional support to enhance communication, and (4) providing providers with feedback on the impact of changes. Implementation of the improvement process decreased the mean psychiatric emergency revisit rate from 5.7% to 4.3% and decreased the variability in monthly rates from a range of 1.83%-9.53% to a range of 3.53%-5.56%. PMID:22849781

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

    E-print Network

    Lindeman, Robert W.

    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

  1. Revisiting public health challenges in the new millennium.

    PubMed

    Anish, Ts; Sreelakshmi, Pr

    2013-07-01

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

  2. Revisiting symmetries of lattice fermions via spin-flavor representation

    E-print Network

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

    2011-12-23

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

  3. Impulsive Spot Heating and Thermal Explosion of Interstellar Grains Revisited

    E-print Network

    Ivlev, A V; Vasyunin, A; Caselli, P

    2015-01-01

    The problem of impulsive heating of dust grains in cold, dense interstellar clouds is revisited theoretically, with the aim to better understand leading mechanisms of the explosive desorption of icy mantles. It is rigorously shown that if the heating of a reactive medium occurs within a sufficiently localized spot (e.g., heating of mantles by cosmic rays), then the subsequent thermal evolution is characterized by a single dimensionless number $\\lambda$. This number identifies a bifurcation between two distinct regimes: When $\\lambda$ exceeds a critical value (threshold), the heat equation exhibits the explosive solution, i.e., the thermal (chemical) explosion is triggered. Otherwise, thermal diffusion causes the deposited heat to spread over the entire grain -- this regime is commonly known as the whole-grain heating. The theory allows us to find a critical combination of the physical parameters that govern the explosion of icy mantles due to impulsive spot heating. In particular, the calculations suggest tha...

  4. Brane inflation revisited after WMAP five-year results

    SciTech Connect

    Ma, Yin-Zhe [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)] [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Zhang, Xin, E-mail: yzm20@cam.ac.uk, E-mail: zhangxin@mail.neu.edu.cn [College of Sciences, Northeastern University, Shenyang 110004, Liaoning (China)] [College of Sciences, Northeastern University, Shenyang 110004, Liaoning (China)

    2009-03-15

    In this paper, we revisit brane inflation models with the WMAP five-year results. The WMAP five-year data favor a red-tilted power spectrum of primordial fluctuations at the level of two standard deviations, which is the same as the WMAP three-year result qualitatively, but quantitatively the spectral index is slightly greater than the three-year value. This result can bring impacts on brane inflation models. According to the WMAP five-year data, we find that the KKLMMT model can survive at the level of one standard deviation, and the fine-tuning of the parameter {beta} can be alleviated to a certain extent at the level of two standard deviations.

  5. Star/Galaxy Separation Revisited : Into the Zone of Avoidance

    E-print Network

    A. Naim

    1997-01-29

    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.

  6. Hadronization revisited: the dynamics behind hadro-chemical equilibrium

    E-print Network

    Reinhard Stock

    2007-03-15

    The multiplicity of hadronic species created in elementary, and in nucleus-nucleus collisions, are known to be well reproduced by the statistical hadronization model, in its canonical and grand-canonical versions.To understand the origin of the implied equilibrium we revisit the hadronization models developed for e+e- annihilation to hadrons which imply spatial color pre-confinement clusters forming at the end of the pQCD evolution, which decays into on-shell hadrons/resonances. The classical ensemble description arises as a consequence of decoherence and phase space dominance during cluster formation, and decay.For A+A collisions we assume that hadronization occurs from similar singlet clusters which will overlap spatially owing to the extreme density. This is imaged in the transition to the grand-canonical ensemble.This transition sets in with increasing A and collision centrality. It can be described by a percolation model.

  7. Tidal Disruption Revisited - Creating Bifurcated Shapes Among Rubble Pile Asteroids

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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

  8. Revisited modeling of Titan’s middle atmosphere electrical conductivity

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  9. Revisiting NMR composite pulses for broadband 2H excitation

    PubMed Central

    Shen, Ming; Roopchand, Rabia; Mananga, Eugene S.; Amoureux, Jean-Paul; Chen, Qun; Boutis, Gregory S.; Hu, Bingwen

    2014-01-01

    Quadrupolar echo NMR spectroscopy of static solids often requires RF excitation that covers spectral widths exceeding 100 kHz, which is difficult to obtain due to instrumental limitations. In this work we revisit four well-known composite pulses (COM-I, II, III and IV) for broadband excitation in deuterium quadrupolar echo spectroscopy. These composite pulses are combined with several phase cycling schemes that were previously shown to decrease finite pulse width distortions in deuterium solid-echo experiments performed with two single pulses. The simulations and experiments show that COM-II and IV composite pulses combined with an 8-step phase cycling aid in achieving broadband excitation with limited pulse width distortions. PMID:25583576

  10. Revisiting NMR composite pulses for broadband (2)H excitation.

    PubMed

    Shen, Ming; Roopchand, Rabia; Mananga, Eugene S; Amoureux, Jean-Paul; Chen, Qun; Boutis, Gregory S; Hu, Bingwen

    2015-01-01

    Quadrupolar echo NMR spectroscopy of static solids often requires RF excitation that covers spectral widths exceeding 100kHz, which is difficult to obtain due to instrumental limitations. In this work we revisit four well-known composite pulses (COM-I, II, III and IV) for broadband excitation in deuterium quadrupolar echo spectroscopy. These composite pulses are combined with several phase cycling schemes that were previously shown to decrease finite pulse width distortions in deuterium solid-echo experiments performed with two single pulses. The simulations and experiments show that COM-II and IV composite pulses combined with an 8-step phase cycling aid in achieving broadband excitation with limited pulse width distortions. PMID:25583576

  11. Feedback instability in the magnetosphere-ionosphere coupling system: Revisited

    SciTech Connect

    Watanabe, T.-H. [National Institute for Fusion Science/Graduate University for Advanced Studies, Toki, Gifu, 509-5292 (Japan)

    2010-02-15

    A coupled set of the reduced magnetohydrodynamic and the two-fluid equations is applied to the magnetosphere-ionosphere (M-I) feedback interactions in relation to growth of quite auroral arcs. A theoretical analysis revisiting the linear feedback instability reveals asymptotic behaviors of the dispersion relation and a non-Hermite property in the M-I coupling. A nonlinear simulation of the feedback instability in the M-I coupling system manifests growth of the Kelvin-Helmholtz-like mode in the magnetosphere as the secondary instability. The distorted vortex and field-aligned current profiles propagating as the shear Alfven waves lead to spontaneous deformation of ionospheric density and current structures associated with auroral arcs.

  12. Revisiting Johnson and Jackson boundary conditions for granular flows

    SciTech Connect

    Li, Tingwen; Benyahia, Sofiane

    2012-07-01

    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.

  13. Energy in synthetic fertilizers and pesticides: Revisited. Final project report

    SciTech Connect

    Bhat, M.G.; English, B.C.; Turhollow, A.F.; Nyangito, H.O. [Tennessee Univ., Knoxville, TN (United States). Dept. of Agricultural Economics and Rural Sociology

    1994-01-01

    Agricultural chemicals that are derived from fossil-fuels are the major energy intensive inputs in agriculture. Growing scarcity of the world`s fossil resources stimulated research and development of energy-efficient technology for manufacturing these chemicals in the last decade. The purpose of this study is to revisit the energy requirements of major plant nutrients and pesticides. The data from manufacturers energy survey conducted by The Fertilizer Institute are used to estimate energy requirements of fertilizers. Energy estimates for pesticides are developed from consulting previously published literature. The impact of technical innovation in the fertilizer industry to US corn, cotton, soybean and wheat producers is estimated in terms of energy-saving.

  14. Revisiting Public Health Challenges in the New Millennium

    PubMed Central

    Anish, TS; Sreelakshmi, PR

    2013-01-01

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

  15. Revisiting the Interaction between the Chaperone Skp and Lipopolysaccharide.

    PubMed

    Burmann, Björn M; Holdbrook, Daniel A; Callon, Morgane; Bond, Peter J; Hiller, Sebastian

    2015-03-24

    The bacterial outer membrane comprises two main classes of components, lipids and membrane proteins. These nonsoluble compounds are conveyed across the aqueous periplasm along specific molecular transport routes: the lipid lipopolysaccharide (LPS) is shuttled by the Lpt system, whereas outer membrane proteins (Omps) are transported by chaperones, including the periplasmic Skp. In this study, we revisit the specificity of the chaperone-lipid interaction of Skp and LPS. High-resolution NMR spectroscopy measurements indicate that LPS interacts with Skp nonspecifically, accompanied by destabilization of the Skp trimer and similar to denaturation by the nonnatural detergent lauryldimethylamine-N-oxide (LDAO). Bioinformatic analysis of amino acid conservation, structural analysis of LPS-binding proteins, and MD simulations further confirm the absence of a specific LPS binding site on Skp, making a biological relevance of the interaction unlikely. Instead, our analysis reveals a highly conserved salt-bridge network, which likely has a role for Skp function. PMID:25809264

  16. Revisiting the quantum Szilard engine with fully quantum considerations

    E-print Network

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

    2012-08-30

    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.

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

    PubMed Central

    2012-01-01

    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

  18. Generalized low-rank approximations of matrices revisited.

    PubMed

    Liu, Jun; Chen, Songcan; Zhou, Zhi-Hua; Tan, Xiaoyang

    2010-04-01

    Compared to singular value decomposition (SVD), generalized low-rank approximations of matrices (GLRAM) can consume less computation time, obtain higher compression ratio, and yield competitive classification performance. GLRAM has been successfully applied to applications such as image compression and retrieval, and quite a few extensions have been successively proposed. However, in literature, some basic properties and crucial problems with regard to GLRAM have not been explored or solved yet. For this sake, we revisit GLRAM in this paper. First, we reveal such a close relationship between GLRAM and SVD that GLRAM's objective function is identical to SVD's objective function except the imposed constraints. Second, we derive a lower bound of GLRAM's objective function, and discuss when the lower bound can be touched. Moreover, from the viewpoint of minimizing the lower bound, we answer one open problem raised by Ye (Machine Learning, 2005), i.e., a theoretical justification of the experimental phenomenon that, under given number of reduced dimension, the lowest reconstruction error is obtained when the left and right transformations have equal number of columns. Third, we explore when and why GLRAM can perform well in terms of compression, which is a fundamental problem concerning the usability of GLRAM. PMID:20172823

  19. The Zeta Herculis binary system revisited. Calibration and seismology

    E-print Network

    P. Morel; G. Berthomieu; J. Provost; F. Thevenin

    2001-09-29

    We have revisited the calibration of the visual binary system Zeta Herculis with the goal to give the seismological properties of the G0 IV sub-giant Zeta Her A. We have used the most recent physical and observational data. For the age we have obtained 3387 Myr, for the masses respectively 1.45 and 0.98 solar mass, for the initial helium mass fraction 0.243, for the initial mass ratio of heavy elements to hydrogen 0.0269 and for the mixing-length parameters respectively 0.92 and 0.90 using the Canuto & Mazitelli (1991, 1992) convection theory. Our results do not exclude that Zeta Her A is itself a binary sub-system; the mass of the hypothetical unseen companion would be smaller than 0.05 solar mass. The adiabatic oscillation spectrum of Zeta Her A is found to be a complicated superposition of acoustic and gravity modes; some of them have a dual character. This greatly complicates the classification of the non-radial modes. The echelle diagram used by the observers to extract the frequencies will work for ell=0, 2, 3. The large difference is found to be of the order of 42 mu Hz, in agreement with the Martic et al. (2001) seismic observations.

  20. Advanced Single-Aisle Transport Propulsion Design Options Revisited

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  1. Factor structure and external validity of the PANSS revisited.

    PubMed

    Van den Oord, Edwin J C G; Rujescu, Dan; Robles, Jaime R; Giegling, Ina; Birrell, Claire; Bukszár, József; Murrelle, Lenn; Möller, Hans-Jürgen; Middleton, Lefkos; Muglia, Pierandrea

    2006-02-28

    Considerable controversy exists concerning the positive and negative syndrome scale (PANSS), one of the most widely used instruments in schizophrenia research. In this article we revisited the factor structure and external validity of the PANSS in a sample of 500 participants with DSM IV diagnoses of schizophrenia. We found that a model with six latent factors provided a relatively good fit, considered adequate by two rules of thumb. Five factors corresponded closely to those typically derived in other studies: Negative, Positive, Excited/Activation, Anxious-Depressed/Dysphoric, and Disorganized/Autistic preoccupation. The sixth factor seemed to have face validity and was labeled Withdrawn. With the exception of Anxious-Depressed/Dysphoric, Cronbach's Alpha ranged from 0.70 to 0.85 suggesting an acceptable internal consistency. External validity was studied through correlations with socio-demographic variables, DSM IV (subtype) diagnoses, clinical characteristics, and drug use. The many significant correlations suggested that the six PANSS scales measure meaningful aspects of schizophrenia. Furthermore, the pattern of correlations varied, providing evidence that the scales assessed partly different aspects of the disease. Our analyses also suggested that some of the controversy about the PANSS can possibly be attributed to methodological factors where the substantial cross-loadings of some PANSS items may play an important role. PMID:16229988

  2. Quantization table design revisited for image/video coding.

    PubMed

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

    2014-11-01

    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

  3. Leber’s Hereditary Optic Neuropathy: The Mitochondrial Connection Revisited

    PubMed Central

    Abu-Amero, Khaled K.

    2011-01-01

    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

  4. Revisiting heritability accounting for shared environmental effects and maternal inheritance.

    PubMed

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

    2015-02-01

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

  5. On kaonic hydrogen. Phenomenological quantum field theoretic model revisited

    E-print Network

    A. N. Ivanov; M. Cargnelli; M. Faber; H. Fuhrmann; V. A. Ivanova; J. Marton; N. I. Troitskaya; J. Zmeskal

    2006-07-04

    We argue that due to isospin and U-spin invariance of strong low-energy interactions the S-wave scattering lengths a^0_0 and a^1_0 of bar-KN scattering with isospin I=0 and I = 1 satisfy the low-energy theorem a^0_0 + 3 a^1_0 = 0 valid to leading order in chiral expansion. In the model of strong low-energy bar-KN interactions at threshold (EPJA 21,11 (2004)) we revisit the contribution of the Sigma(1750) resonance, which does not saturate the low-energy theorem a^0_0 + 3 a^1_0 = 0, and replace it by the baryon background with properties of an SU(3) octet. We calculate the S-wave scattering amplitudes of K^-N and K^-d scattering at threshold. We calculate the energy level displacements of the ground states of kaonic hydrogen and kaonic deuterium. The result obtained for kaonic hydrogen agrees well with recent experimental data by the DEAR Collaboration. We analyse the cross sections for elastic and inelastic K^-p scattering for laboratory momenta of the incident K^- meson from the domain 70 MeV/c < p_K < 150 MeV/c. The theoretical results agree with the available experimental data within two standard deviations.

  6. The significance of the integrated Sachs-Wolfe effect revisited

    NASA Astrophysics Data System (ADS)

    Giannantonio, Tommaso; Crittenden, Robert; Nichol, Robert; Ross, Ashley J.

    2012-11-01

    We revisit the state of the integrated Sachs-Wolfe (ISW) effect measurements in light of newly available data and address criticisms about the measurements which have recently been raised. We update the data set previously assembled by Giannantonio et al. to include new data releases for both the cosmic microwave background and the large-scale structure of the Universe. We find that our updated results are consistent with previous measurements. By fitting a single template amplitude, we now obtain a combined significance of the ISW detection at the 4.4? level, which fluctuates by ˜0.4? when alternative data cuts and analysis assumptions are considered. We also make new tests for systematic contaminations of the data, focusing in particular on the issues raised by Sawangwit et al. Amongst them, we address the rotation test, which aims at checking for possible systematics by correlating pairs of randomly rotated maps. We find results consistent with the expected data covariance, no evidence for enhanced correlation on any preferred axis of rotation, and therefore no indication of any additional systematic contamination. We publicly release the results, the covariance matrix and the sky maps used to obtain them.

  7. Revisiting the Monoamine Hypothesis of Depression: A New Perspective

    PubMed Central

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

    2014-01-01

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

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

    PubMed

    Hughes, Adam D; Kelly, Maeve S; Black, Kenneth D; Stanley, Michele S

    2012-01-01

    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

  9. V838 Monocerotis revisited: Space phenomenon imitates art

    NASA Astrophysics Data System (ADS)

    2004-03-01

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

  10. Central exclusive ? c meson production at the Tevatron revisited

    NASA Astrophysics Data System (ADS)

    Harland-Lang, L. A.; Khoze, V. A.; Ryskin, M. G.; Stirling, W. J.

    2010-02-01

    Motivated by the recent experimental observation of exclusive ? c events at the Tevatron, we revisit earlier studies of central exclusive scalar ? c0 meson production, before generalising the existing formalism to include ? c1 and ? c2 mesons. Although ? c0 production was previously assumed to be dominant, we find that the ? c1 and ? c2 rates for the experimentally considered ? c ? J/ ? ?? ? + ? - ? decay process are in fact comparable to the ? c0 rate. We have developed a new Monte Carlo event generator, SuperCHIC, which models the central exclusive production of the three ? c states via this decay chain, and have explored possible ways of distinguishing them, given that their mass differences are not resolvable within the current experimental set-up. Although we find that the severity of current experimental cuts appears to preclude this, the acceptance does not change crucially between the three states and so our conclusions regarding the overall rates remain unchanged. This therefore raises the interesting possibility that exclusive ? c1 and ? c2 production has already been observed at the Tevatron.

  11. Neural network modelling of CIMIS-ET0 (revisited)

    NASA Astrophysics Data System (ADS)

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

    2009-04-01

    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.

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

    PubMed

    Burbey, T J

    2001-01-01

    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

  13. Fast dynamics in glass-forming polymers revisited

    SciTech Connect

    Colmenero, J.; Arbe, A. [Univ. del Pais Vasco, San Sebastian (Spain). Dept. de Fisica de Materiales; Mijangos, C.; Reinecke, H. [CSIC, Madrid (Spain). Inst. de Ciencia y Tecnologia de Polimeros

    1997-12-31

    The so called fast-dynamics of glass-forming systems as observed by time of flight (TOF) neutron scattering techniques is revisited. TOF-results corresponding to several glass-forming polymers with different chemical microstructure and glass-transition temperature are presented together with the theoretical framework proposed by the authors to interpret these results. The main conclusion is that the TOF-data can be explained in terms of quasiharmonic vibrations and the particular short time behavior of the segmental dynamics. The segmental dynamics display in the very short time range (t {approx} 2 ps) a crossover from a simple exponential behavior towards a non-exponential regime. The first exponential decay, which is controlled by C-C rotational barriers, can be understood as a trace of the behavior of the system in absence of the effects (correlations, cooperativity, memory effects {hor_ellipsis}) which characterize the dense supercooled liquid like state against the normal liquid state. The non-exponential regime at t > 2 ps corresponds to what is usually understood as {alpha} and {beta} relaxations. Some implications of these results are also discussed.

  14. Revisiting Directed Polymers with heavy-tailed disorder

    E-print Network

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

    2014-11-05

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

  15. Psychological Well-Being Revisited: Advances in Science and Practice

    PubMed Central

    Ryff, Carol D.

    2014-01-01

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

  16. Cherry Hill revisited: Background events and photovoltaic technology status

    NASA Astrophysics Data System (ADS)

    Herwig, Lloyd O.

    1999-03-01

    The workshop on "Photovoltaic Conversion of Solar Energy for Terrestrial Applications" was held in Cherry Hill, New Jersey, on October 23-25, 1973, under the sponsorship of the Research Applied to National Needs (RANN) program of the National Science Foundation (NSF). The workshop was organized in recognition of several pressing needs. These included (1) promoting dialog and exchange of information among participants in the field: (2) setting and documenting of consensus photovoltaic technology goals, plans, and budget resources for potential use in NSF/RANN program development: and, (3) coordinating the research, manufacturing, and commercialization communities. There were about 135 participants in the workshop, which was organized by NSF/RANN staff with major assistance from Jet Propulsion Laboratory (JPL) staff. Cherry Hill Revisited is presented in two parts: Part 1 by Dr. Lloyd O. Herwig, former Director of Advanced Solar Energy Research and Development Division in the NSF's Research Applied to National Needs Directorate; and, Part 2 by Dr. H. Richard Blieden, former Chief of the Photovoltaic Branch within the Advanced Solar Energy Research and Development Division. Part 1 is an overview of prior technology development and the background events surrounding the start-up and early years of the terrestrial solar technologies initiative leading up to the Cherry Hill Photovoltaic Workshop. Part 2 summarizes the conclusions and general outcome of the workshop.

  17. Revisiting the quantum Szilard engine with fully quantum considerations

    SciTech Connect

    Li, Hai [School of Physics, Beijing Institute of Technology, Beijing 100081 (China) [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); School of Information and Electronics Engineering, Shandong Institute of Business and Technology, Yantai 264000 (China); Zou, Jian, E-mail: zoujian@bit.edu.cn [School of Physics, Beijing Institute of Technology, Beijing 100081 (China)] [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Li, Jun-Gang; Shao, Bin [School of Physics, Beijing Institute of Technology, Beijing 100081 (China)] [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Wu, Lian-Ao [Department of Theoretical Physics and History of Science, The Basque Country University (EHU/UPV), P.O. Box 644, ES-48080 Bilbao (Spain) [Department of Theoretical Physics and History of Science, The Basque Country University (EHU/UPV), P.O. Box 644, ES-48080 Bilbao (Spain); IKERBASQUE, Basque Foundation for Science, ES-48011 Bilbao (Spain)

    2012-12-15

    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{yields}{infinity} or the temperature of the bath T{yields}{infinity} the QSZE reduces to the classical Szilard engine (CSZE), and the total work satisfies the relation W{sub tot}=k{sub B}Tln2 as obtained by Sang Wook Kim et al. [S.W. Kim, T. Sagawa, S. De Liberato, M. Ueda, Phys. Rev. Lett. 106 (2011) 070401] for one particle case. - Highlights: Black-Right-Pointing-Pointer For the first time analyze the QSZE by considering energy level shifts. Black-Right-Pointing-Pointer Find different roles played by classical and quantum information in the QSZE. Black-Right-Pointing-Pointer The amount of work extracted depends on the cyclic strategies of the QSZE. Black-Right-Pointing-Pointer Verify that the QSZE will reduce to the CSZE in the classical limits.

  18. Internal wave focusing revisited; a reanalysis and new theoretical links

    NASA Astrophysics Data System (ADS)

    Lam, Frans-Peter A.; Maas, Leo R. M.

    2008-02-01

    An experiment which discussed the appearance of an internal wave attractor in a uniformly stratified, free-surface fluid [Maas, L.R.M., Benielli, D., Sommeria, J., Lam, F.-P.A., 1997. Observation of an internal wave attractor in a confined, stably stratified fluid. Nature 388(6642), 557-561] is revisited. This is done in order to give a more detailed and more accurate description of the underlying focusing process. Evolution of the attractor can now be quantified. For the tank with one sloping sidewall, and for the parameter regime (density stratification, forcing frequency) studied, the inverse exponential growth rate determined at several locations in the fluid turns out to be 122 s always. Only the start and duration of the growth differed: away from the attractor region it appeared later and of shorter duration. Here, these features are interpreted by employing a new theoretical basis that incorporates an external forcing via a surface boundary condition (an infinitesimal barotropic seiche) and that describes the solution in terms of propagating waves.

  19. NLTE in a Hot Hydrogen Star: Auer & Mihalas Revisited

    NASA Astrophysics Data System (ADS)

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

    2003-01-01

    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.

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

    ERIC Educational Resources Information Center

    Alim, H. Samy

    2005-01-01

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

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

    E-print Network

    Rivlin, Ehud

    of the Internet, striving at providing users with search results most relevant to their information needsPlacing Search in Context: The Concept Revisited Lev Finkelstein, Evgeniy Gabrilovich 1 , Yossi describe a new paradigm for performing search in context. In the IntelliZap system we developed, search

  2. Cascade Encryption Revisited Peter Gazi 1,2 and Ueli Maurer 1

    E-print Network

    Cascade Encryption Revisited Peter GaŸzi 1,2 and Ueli Maurer 1 1 ETH ZË?urich, Switzerland encryption is an impor­ tant and well­studied problem in theoretical cryptography with practical implications. It is well­known that double encryption improves the secu­ rity only marginally, leaving triple encryption

  3. Proof of Plaintext Knowledge for Code-Based Public-Key Encryption Revisited

    E-print Network

    Morozov, Kirill

    Proof of Plaintext Knowledge for Code-Based Public-Key Encryption Revisited Rong Hu , Kirill in security arguments of proof of plaintext knowledge (PPK) and verifiable encryption for the McEliece public key encryption (PKE) proposed by Morozov and Takagi at ACISP'2012. We fix the latter result by showing

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

    E-print Network

    International Association for Cryptologic Research (IACR)

    Public-Key Encryption Resilient Against Linear Related-Key Attacks Revisited Hui Cui School-key encryption scheme in the setting of related-key attacks. Bellare, Paterson and Thom- son (Asiacrypt'12, this is impractical in real world. In this paper, we concentrate on the security of public-key encryption schemes

  5. Dictionary Approximation In this chapter, we revisit the topics of dictionary design and implementation. The

    E-print Network

    Zakhor, Avideh

    239 Chapter 6 Dictionary Approximation In this chapter, we revisit the topics of dictionary design dictionary of separable 2­D Gabor functions. This dictionary was first introduced in [45] and was completely described in Chapter 2. Additional dictionary designs have been proposed by others in order to improve

  6. BurmesterDesmedt TreeBased Key Transport Revisited: Provable Security without Broadcast

    E-print Network

    . Unfortunately, in [BD95] security proofs are not included, and so far these proposals have not been putBurmester­Desmedt Tree­Based Key Transport Revisited: Provable Security without Broadcast Jens­to­point connections, and its security against active adver­ saries is proven in the standard model under the Decision

  7. Concluding Messages: The Toolbox Revisited--Paths to Degree Completion from High School through College

    ERIC Educational Resources Information Center

    Adelman, Clifford

    2005-01-01

    Compared to its predecessor, "Answers in the Tool Box," the preponderance of the "Toolbox Revisited" story has been on the postsecondary side of the matriculation line. Implicitly, it calls on colleges, universities, and community colleges to be a great deal more interventionary in the precollegiate world, to be more self-reflective about the…

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

    E-print Network

    Bearing capacity of spatially random soil: the undrained clay Prandtl problem revisited D. V, an investigation has been performed into the bearing capacity of undrained clays with spatially vary- ing shear strength. The object of the investigation is to determine the extent to which variance and spatial correla

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

    E-print Network

    Danforth, Bryan Nicholas

    Relative Age Effects and the PhD 1 Revisiting Gladwell's Hockey Players: Influence of Relative Age examine the influence of relative age effects (RAE) upon whether someone earns the PhD. Drawing, or conclusions contained in this report. #12;Relative Age Effects and the PhD 2 1. INTRODUCTION Parental

  10. REVISITING “MASS COMMUNICATION” AND THE “WORK” OF THE AUDIENCE IN THE NEW MEDIA ENVIRONMENT

    Microsoft Academic Search

    Philip M. Napoli

    2008-01-01

    This paper revisits the concept of mass communication, which has faced persistent challenges to its continued relevance in light of changes that have taken place in the media environment. This paper offers a counterpoint to claims of the term’s diminished relevance, as well as to some recent efforts to reposition the term, by putting forth an interpretive approach that is

  11. NON-LINEAR SIMILARITY REVISITED IAN HAMBLETON AND ERIK K. PEDERSEN

    E-print Network

    Pedersen, Erik Kjær

    NON-LINEAR SIMILARITY REVISITED IAN HAMBLETON isomorphic, then such a homeomorphism is called a non-linear similarity. The topological classification] constructed the first exam* *ples of non-linear similarities. The simplest occurs for G = Z=8, but they also

  12. NON-LINEAR SIMILARITY REVISITED IAN HAMBLETON AND ERIK K. PEDERSEN

    E-print Network

    NON-LINEAR SIMILARITY REVISITED IAN HAMBLETON AND ERIK K isomorphic, then such a homeomorphism is called a non- linear similarity. The topological classification [1] constructed the first examples of non-linear similarities* *. The simplest occurs for G = Z=8

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

    Microsoft Academic Search

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

    2010-01-01

    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

  14. Revisiting the Schoolwide Enrichment Model--An Approach to Gifted Programming.

    ERIC Educational Resources Information Center

    Gibson, Sherry; Efinger, Joan

    2001-01-01

    This article provides a consistent framework through which educators may better identify and serve gifted and talented students by revisiting the dynamics of the Schoolwide Enrichment Model (SEM) in relation to student achievement. Delivery and structural and organizational components of SEM are discussed, along with research supporting the model.…

  15. The Heavy Burden of the State: Revisiting the History of Labor Law in the Interwar Period

    Microsoft Academic Search

    Christopher L. Tomlins

    2000-01-01

    This Article reflects on possible conclusions to be drawn from this symposium. The article concludes that individually, these authors have demonstrated the returns to be gained by pushing labor law history into new empirical and conceptual areas. Collectively, however, their achievement is somewhat different, for collectively they recommend that we revisit what is ostensibly familiar to us.

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

    ERIC Educational Resources Information Center

    Gopinathan, S.

    2007-01-01

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

  17. Revisiting the Quantitative-Qualitative Debate: Implications for Mixed-Methods Research

    Microsoft Academic Search

    Joanna E. M. Sale; Lynne H. Lohfeld; Kevin Brazil

    2002-01-01

    Health care research includes many studies that combine quantitative and qualitative methods. In this paper, we revisit the quantitative-qualitative debate and review the arguments for and against using mixed-methods. In addition, we discuss the implications stemming from our view, that the paradigms upon which the methods are based have a different view of reality and therefore a different view of

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

    ERIC Educational Resources Information Center

    Lawy, Robert; Armstrong, Paul

    2009-01-01

    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…

  19. OptimalSupply of a Depletable Resource with a Backstop Technology: Heal's Theorem Revisited

    E-print Network

    Oren, Shmuel S.

    OptimalSupply of a Depletable Resource with a Backstop Technology: Heal's Theorem Revisited SHMUEL states that if the extraction cost of a depletable resource increases with cumulative extraction, and if a backstop technology exists, the user cost of the depletable resource declines to zero at the date

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

    ERIC Educational Resources Information Center

    Han, Soonghee

    2007-01-01

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

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

    E-print Network

    Florida, University of

    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

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

    Microsoft Academic Search

    Linda Tauscher; Saul Greenberg

    1997-01-01

    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

  3. Revisiting a Limit on Efficient Quantum Computation Tarsem S. Purewal Jr.

    E-print Network

    Geller, Michael R.

    Revisiting a Limit on Efficient Quantum Computation Tarsem S. Purewal Jr. Department of Computer and no knowledge of quan- tum mechanics. Keywords Computational Complexity, Quantum Computing 1. INTRODUCTION In the race to build a quantum computer, the question of whether or not such a machine will be more useful

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

    E-print Network

    Al Hanbali, Ahmad

    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

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

    E-print Network

    Schuettpelz, Eric

    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

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

    E-print Network

    Kersting, Kristian

    Where 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 already in the early 90ies, many recent papers on mobility mining seem to be unaware of it. We therefore

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

    Microsoft Academic Search

    Shino Shiode

    2012-01-01

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

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

    E-print Network

    Demouchy, Sylvie

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

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

    ERIC Educational Resources Information Center

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

    2009-01-01

    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.…

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

    E-print Network

    Matias, Yossi

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

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

    Microsoft Academic Search

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

    2001-01-01

    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

  12. Perspectives on types of schools from Ghana and Pakistan: revisiting the relationship between

    E-print Network

    Steiner, Ullrich

    Perspectives on types of schools from Ghana and Pakistan: revisiting the relationship between in both Ghana and Pakistan. While parents focus more on the economic opportunities that are becoming providers in the field of education in both Ghana and Pakistan. This has created a discernable rise

  13. The solution of an open XXZ chain with arbitrary spin revisited

    E-print Network

    Rajan Murgan; Christopher Silverthorn

    2015-01-19

    The Bethe ansatz solutions for an open XXZ spin chain with arbitrary spin with N sites and nondiagonal boundary terms are revisited. The anisotropy parameter, for cases considered here, has values \\eta = i \\pi r/q, where r and q are positive integers with q restricted to odd integers. Numerical results are presented to support the solutions.

  14. The solution of an open XXZ chain with arbitrary spin revisited

    NASA Astrophysics Data System (ADS)

    Murgan, Rajan; Silverthorn, Chris

    2015-02-01

    The Bethe ansatz solutions for an open XXZ spin chain with arbitrary spin with N sites and nondiagonal boundary terms are revisited. The anisotropy parameter, for cases considered here, has values ? = i? \\frac{r}{q} , where r and q are positive integers with q restricted to odd integers. Numerical results are presented to support the solutions.

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

    ERIC Educational Resources Information Center

    Nikolic, Hrvoje

    2012-01-01

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

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

    ERIC Educational Resources Information Center

    Rappleye, Jeremy

    2015-01-01

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

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

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

    ERIC Educational Resources Information Center

    Kuzyk, Raya

    2006-01-01

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

  19. Decoding information in the honeybee dance: revisiting the tactile hypothesis Mariana Gil*, Rodrigo J. De Marco

    E-print Network

    Menzel, Randolf - Institut für Biologie

    Decoding information in the honeybee dance: revisiting the tactile hypothesis Mariana Gil*, Rodrigo-00526 Keywords: Apis mellifera dance communication honeybee mechanosensory input tactile stimulus waggle dance The waggle dance of honeybees, Apis mellifera, is one of the most remarkable communication systems

  20. The game of red and blue revisited: propensities, subjective probabilities, and the goodness-of-fit

    E-print Network

    Hennig, Christian

    The game of red and blue revisited: propensities, subjective probabilities, and the goodness@stats.ucl.ac.uk November 29, 2006 Abstract "The game of red and blue" is an example given by Gillies (2000) to illustrate, which is crucial for Gillies' interpretation, is subject to serious dif- ficulties, one of which

  1. The game of red and blue revisited: propensities, subjective probabilities, and the goodness-of-fit

    E-print Network

    Guillas, Serge

    The game of red and blue revisited: propensities, subjective probabilities, and the goodness@stats.ucl.ac.uk December 4, 2006 Abstract "The game of red and blue" is an example given by Gillies (2000) to illustrate, which is crucial for Gillies' interpretation, is subject to serious dif- ficulties, one of which

  2. FTIR spectroscopy of biofluids revisited: an automated approach to spectral biomarker identification

    E-print Network

    Gerwert, Klaus

    FTIR spectroscopy of biofluids revisited: an automated approach to spectral biomarker¨uningb and Klaus Gerwert*a The extraction of disease specific information from Fourier transform infrared (FTIR sensitivity of modern FTIR spectrometers, automatisation of sample preparation and modern bioinformatics

  3. Revisiting the Relationship between Software Architecture and Requirements: the case of Dynamically Adaptive Systems

    Microsoft Academic Search

    Nelly Bencomo; Paul Grace; Pete Sawyer

    This paper revisits the relationship between software architecture and requirements focusing on the case of self- adaptive systems. The authors present their view of the state-of-the-art, including their own work, on both areas and their contribution towards the development of self- adaptive systems. The authors support the claim that there i s no fundamental distinction between architectural decisio ns and

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

    E-print Network

    Howk, Jay Christopher

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

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

    E-print Network

    Paris-Sud XI, Université de

    1 Crystal Structure of A-amylose: a Revisit from Synchrotron Microdiffraction Analysis of Single;2 Abstract The three-dimensional structure of A-amylose crystals, as a model of the crystal domains of A the resolution of important new fine details. These include a distortion of the amylose double helices resulting

  6. Reading Researchers in Search of Common Ground: The Expert Study Revisited. 2nd Edition

    ERIC Educational Resources Information Center

    Flippo, Rona F., Ed.

    2011-01-01

    In "Reading Researchers in Search of Common Ground, Second Edition", Rona F. Flippo revisits her study, in which she set out to find common ground among experts in the much-fragmented field of reading research. The original edition, featuring contributions from participants in the study, commentary from additional distinguished literacy scholars…

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

    E-print Network

    Young, R. Michael

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

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

    E-print Network

    Schulte, Jim

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

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

    ERIC Educational Resources Information Center

    Baker, Bruce D.

    2012-01-01

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

  10. Ambiguity Advantage Revisited: Two Meanings Are Better than One when Accessing Chinese Nouns

    ERIC Educational Resources Information Center

    Lin, Chien-Jer Charles; Ahrens, Kathleen

    2010-01-01

    This paper revisits the effect of lexical ambiguity in word recognition, which has been controversial as previous research reported advantage, disadvantage, and null effects. We discuss factors that were not consistently treated in previous research (e.g., the level of lexical ambiguity investigated, parts of speech of the experimental stimuli,…

  11. Asymptotic Electromagnetic Fields in Non-relativistic QED: the Problem of Existence Revisited

    E-print Network

    Asymptotic Electromagnetic Fields in Non-relativistic QED: the Problem of Existence Revisited-relativistic quantum mechanical particles coupled minimally to the soft modes of the quantized electromagnetic field of arbitrarily high energy. Previously, upper bounds on the photon energies seemed necessary in the case of n > 1

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

    E-print Network

    Paris-Sud XI, Université de

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

  13. How to Compute the Area of a Triangle: a Formal Revisit with a tighter error bound

    E-print Network

    Paris-Sud XI, Université de

    1 How to Compute the Area of a Triangle: a Formal Revisit with a tighter error bound Sylvie Boldo for the computation of the area of a triangle. When the triangle is needle-like, the common formula has a very poor--floating-point arithmetic, formal proof, Coq, triangle, underflow ! 1 INTRODUCTION Floating-point (FP) arithmetic is seen

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

    ERIC Educational Resources Information Center

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

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

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

    E-print Network

    Paris-Sud XI, Université de

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

  16. 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

  17. The MATE/GNOME Proposals for Anaphoric Annotation, Revisited Massimo Poesio

    E-print Network

    Poesio, Massimo

    The MATE/GNOME Proposals for Anaphoric Annotation, Revisited Massimo Poesio University of Essex since it was proposed, the MATE scheme for anaphoric annotation has been used in a variety of annotation modifications. 1 Introduction The MATE `meta-scheme' for anaphora annotation (Poe- sio et al., 1999) is one

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

    ERIC Educational Resources Information Center

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

    2012-01-01

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

  19. LE CONCEPT D'INTERACTIVIT DE SIMONS REVISIT L'AUNE DES SYSTMES DE

    E-print Network

    Paris-Sud XI, Université de

    diagnostique, stratégie environnementale, tableaux de bord verts. Abstract : We propose in this paper to revisit the concept of interactive control, highlighted by Robert Simons, examining the use of "environmental control systems" in ten French companies proactive in ecology. By showing that interactivity

  20. Perspective: Evolution of Flower Color in the Desert Annual Linanthus parryae: Wright Revisited

    E-print Network

    Bierzychudek, Paulette

    of a long- standing debate among evolutionary biologists. At issue is whether the flower color polymorphismPerspective: Evolution of Flower Color in the Desert Annual Linanthus parryae: Wright Revisited(7), 2001, pp. 1269-1282 PERSPECTIVE: EVOLUTION OF FLOWER COLOR IN THE DESERT ANNUAL LINANTHUS PARRYAE

  1. Nonlinear Transform Coding: Polar Coordinates Revisited Demba E. Ba and Vivek K Goyal

    E-print Network

    Goyal, Vivek K

    Nonlinear Transform Coding: Polar Coordinates Revisited Demba E. Ba and Vivek K Goyal Massachusetts Institute of Technology Transform coding is central to standards for audio, image and video coding. In con- ventional transform coding, the encoder first performs a linear transformation, followed by uniform scalar

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

    ERIC Educational Resources Information Center

    Dannels, Deanna P.

    2015-01-01

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

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

    Microsoft Academic Search

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

    2012-01-01

    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

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

    Microsoft Academic Search

    Olukayode D. Akinyemi; Thomas J. Sauer; Yemi S. Onifade

    2011-01-01

    Determination of thermal conductivities of porous media using the contact method was revisited and revalidated. Thermal conductivities of granite and clay were determined in the laboratory with and without the use of thermal interface material (TIM) (Arctic Silver®) to reduce contact resistance. KD2 probe was also used with and without TIM to compare results. Thermal conductivity of dry clay sample

  5. The CH4 structure in Titan's upper atmosphere revisited R. V. Yelle,2

    E-print Network

    Yelle, Roger V.

    The CH4 structure in Titan's upper atmosphere revisited J. Cui,1 R. V. Yelle,2 D. F. Strobel,3 I. C the CH4 structure in Titan's upper atmosphere combining the Cassini Ion Neutral Mass Spectrometer (INMS on Titan. Ignoring ionospheric chemistry, the optimal CH4 loss rate is $3 Â 1027 sÀ1 or 80 kg sÀ1

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

    E-print Network

    Saidak, Filip

    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

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

    ERIC Educational Resources Information Center

    Ledesma, Maria C.

    2013-01-01

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

  8. Increasing the Degrees of Freedom in Future Group Randomized Trials: The "df*" Method Revisited

    ERIC Educational Resources Information Center

    Murray, David M.; Blitstein, Jonathan L.; Hannan, Peter J.; Shadish, William R.

    2012-01-01

    Background: This article revisits an article published in Evaluation Review in 2005 on sample size estimation and power analysis for group-randomized trials. With help from a careful reader, we learned of an important error in the spreadsheet used to perform the calculations and generate the results presented in that article. As we studied the…

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

    E-print Network

    Boyer, Edmond

    of these biases for urban household disposable income inequality over the 1988-2002 period, by using new data inequality in urban household disposable income using the square root of the total number of household1 Urban income inequality in China revisited (1988-2002)* Sylvie Démurger HIEBS, The University

  10. Making Productive Use of Four Models of School English: A Case Study Revisited

    ERIC Educational Resources Information Center

    Macken-Horarik, Mary

    2014-01-01

    At a time when political leaders and media pundits seek to narrow the English curriculum and reduce its knowledge structure to the "basics," it is helpful to revisit the potential of different approaches to learning in English that have evolved over time. In this paper I reflect on the semantic features of personal growth, cultural…

  11. Revisiting Flow-Based Load Balancing: Stateless Path Selection in Data Center Networks

    E-print Network

    Bonaventure, Olivier

    Revisiting Flow-Based Load Balancing: Stateless Path Selection in Data Center Networks Gregory elephant flows in large data center networks. Keywords: Load Balancing; Data Center Networks; Multipath TCP 1. Introduction Load balancing plays a key role in enterprise, data center and ISP networks

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

    ERIC Educational Resources Information Center

    Guerard, Katherine; Tremblay, Sebastien

    2008-01-01

    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,…

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

    E-print Network

    Long, Bernard

    MERCURY CONCENTRATIONS IN LAKE SEDIMENTS ­ REVISITING THE PREDICTIVE POWER OF CATCHMENT MORPHOMETRY-Ville, Montr´eal (PQ), H3C 3P8, Canada; 2 Department of Biology, University of Victoria, P.O. Box 3020, Stn. CSC, Victoria (British Columbia), V8W 3N5, Canada ( author for correspondence, e-mail: mkainz

  14. Revisiting elliptical satellite orbits to enhance the O3b constellation

    E-print Network

    Wood, Lloyd

    leaves apogee, another satellite entering apogee takes its place, with handover of communication, from1 Revisiting elliptical satellite orbits to enhance the O3b constellation Lloyd Wood University satellite coverage of locations at high latitudes. We review the history of use of these orbits

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

    E-print Network

    Nowak, Martin A.

    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

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

    E-print Network

    Lill, John T.

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

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

    ERIC Educational Resources Information Center

    Weisburg, Michael; Ullmer, Eldon J.

    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…

  18. Interest rates and budget deficits revisited–evidence from the G7 countries

    Microsoft Academic Search

    David Hauner; Manmohan S. Kumar

    2011-01-01

    This article revisits whether budget deficits affect interest rates, and broadens the literature by examining whether financial globalization has changed this relationship. A structural model of interest determination is extended to account for the fact that official capital flows are determined differently than private flows and is estimated for a 1960–2005 G7 panel. We find that deficits have a significant

  19. Implementing Core IS Capabilities:: Feeny-Willcocks IT Governance and Management Framework Revisited

    Microsoft Academic Search

    Leslie Willcocks; David Feeny; Nancy Olson

    2006-01-01

    In 1998, Feeny and Willcocks published a core IS capabilities framework suggesting four tasks and nine capabilities for any future IT function. This paper revisits the framework, examining the challenges and learning points from its implementation in three organizations from 2000 to 2005. The cases, studied longitudinally, involved a medium-sized organization beginning to outsource, and a multinational and a national

  20. Globalisation, the Singapore developmental state and education policy: a thesis revisited

    Microsoft Academic Search

    S. Gopinathan

    2007-01-01

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

  1. 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. In TPM2.0, a single signature primitive is proposed to sup- port various signature schemes including measure the practical impact of the SDH oracle in TPM2.0 and show the security strength of these signature

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

    Microsoft Academic Search

    Jay F. Tu

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

  3. Exploring Visitors' Experiences and Intention to Revisit a Heritage Destination: The Case for Lukang, Taiwan

    Microsoft Academic Search

    Yu-Ju Wang; Chihkang Wu; Jingxue Yuan

    2010-01-01

    The purpose of this study was to identify the factors that affect visitors' decisions to visit and then revisit a “community-heritage” destination, namely Lukang, Taiwan, a popular heritage site. Specifically, this study examined the impact of the purpose of the visit, the trip experience, the destination attributes, the destination image, and the market communication tools for each visitor's experience. In

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

    E-print Network

    Sklenak, Stepan

    ALUMINUM SITING IN THE ZSM-22 AND THETA-1 ZEOLITES REVISITED: A QM/MM STUDY Stepan SKLENAKa1 on the occasion of his 80th birthday. The Al siting in the silicon rich ZSM-22 and Theta-1 zeolites of the TON. Keywords: QM/MM calculations; Ab initio calculations; BLYP; GIAO; Zeolites; 27 Al 3Q MAS NMR spectroscopy

  5. ELSEVIER Information processing Letters 64 ( 1997) 155-160 Revisiting the COUNTER algorithms for list update

    E-print Network

    Mitzenmacher, Michael

    ratio smaller than 12/7 for any mixture of COUNTER algorithms using the type of potential function the type of potential function argument that has been used so far. Next, we develop new lower boundsELSEVIER Information processing Letters 64 ( 1997) 155-160 Revisiting the COUNTER algorithms

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

    Microsoft Academic Search

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

    2008-01-01

    The problem of phase mixing of shear Alfvén waves is revisited taking into account dissipative phenomena specific for the solar corona. In regions of space plasmas where the dynamics is controlled by the magnetic field, transport coefficients become anisotropic with transport mechanism having different behavior and magnitude depending on the orientation with respect to the ambient magnetic field. Taking into

  7. Revisiting the doping requirement for low power junctionless MOSFETs

    NASA Astrophysics Data System (ADS)

    Singh Parihar, Mukta; Kranti, Abhinav

    2014-07-01

    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.

  8. PHOTOEVAPORATION OF CIRCUMSTELLAR DISKS REVISITED: THE DUST-FREE CASE

    SciTech Connect

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

    2013-08-20

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

  9. Revisiting the Interpretation of Thorium Abundances at Hansteen Alpha

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  10. Revisiting evidence for sustainability of bushmeat hunting in West Africa.

    PubMed

    Waite, T A

    2007-09-01

    Bushmeat hunting, a key source of dietary protein, has been implicated as a major extinction threat to tropical vertebrate species in West Africa. Ideally, any such hunting of wild species should be done sustainably, with off-take levels low enough to ensure viability of harvested species. Recent work purports to show that a mature bushmeat market in a major city in Ghana operates sustainably after depletion of vulnerable, slow-reproducing species (Cowlishaw and others 2005). I revisit two aspects of this work. First, I retest the prediction that larger species are transported to the market from greater distances, as expected if overexploitation depletes large species close to the city. Cowlishaw and others failed to find a significantly positive relationship between species-specific body mass and distance between capture site and the market. However, my reanalysis provides evidence for a positive relationship after all, consistent with unsustainable harvesting. In particular, ungulate species were harvested significantly farther from the market than smaller-bodied rodent species. Second, I caution that just because species "persist" in the marketplace in no way implies that they can withstand hunting pressure elsewhere and so should be of little concern to conservationists. I reveal that such species, despite their high intrinsic rates of population growth, are not robust elsewhere. Several of them have disappeared from a network of protected areas in Ghana (Brashares and others 2001). I show that faster-reproducing species are not necessarily more likely to persist in protected areas. The mere presence of fast-reproducing species in a mature bushmeat market should not be construed as generalizable robustness; criteria for ecological sustainability should ensure viability; and harvested species should be robust, not highly prone to extinction, in protected areas. PMID:17638049

  11. Revisiting theories with enhanced Higgs couplings to weak gauge bosons

    NASA Astrophysics Data System (ADS)

    Chang, Spencer; Newby, Christopher A.; Raj, Nirmal; Wanotayaroj, Chaowaroj

    2012-11-01

    Based on recent LHC Higgs analyses and in anticipation of future results we revisit theories where Higgs bosons can couple to weak gauge bosons with enhanced strength relative to the Standard Model value. Specifically, we look at the Georgi-Machacek model and its generalizations where higher “spin” representations of SU(2)L break electroweak symmetry while maintaining custodial SU(2). In these theories, there is not only a Higgs-like boson but partner Higgs scalars transforming under representations of custodial SU(2), leading to a rich phenomenology. These theories serve as a consistent theoretical and experimental framework to explain enhanced couplings to gauge bosons, including fermiophobic Higgses. We focus on the phenomenology of a neutral scalar partner to the Higgs, which is determined once the Higgs couplings are specified. Depending on the parameter space, this partner could have (i) enhanced fermion and gauge boson couplings and should be searched for at high mass (>600GeV), (ii) suppressed couplings and could be searched for at lower masses, where the Standard Model Higgs has already been ruled out, and (iii) fermiophilic couplings, where it can be searched for in heavy Higgs and top resonance searches. In the first two regions, the partner also has substantial decay rates into a pair of Higgs bosons. We touch briefly on the more model-dependent effects of the nontrivial SU(2)C multiplets, which have exotic signals, such as a doubly charged Higgs. We also discuss how the loop induced effects of these scalars tend to reduce the Higgs decay rate to photons, adding an additional uncertainty when extracting the couplings for the Higgs boson.

  12. Antisolar differential rotation of the K1-giant ? Geminorum revisited

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    E-print Network

    Stern, Claudio

    1991-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

  15. Revisited Inventory of Glaciers on Axel Heiberg Island, Nunavut

    NASA Astrophysics Data System (ADS)

    Thomson, L.; Osinski, G.

    2009-05-01

    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.

  16. Effective-Medium Models for Marine Gas Hydrates, Mallik Revisited

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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.

  17. REVISITING SCALING RELATIONS FOR GIANT RADIO HALOS IN GALAXY CLUSTERS

    SciTech Connect

    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

    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.

  18. Revisiting Scaling Relations for Giant Radio Halos in Galaxy Clusters

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  19. Revisiting Scaling Relations for Giant Radio Halos in Galaxy Clusters

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  20. The Angular Momentum of Baryons and Dark Matter Halos Revisited

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

  1. Hydrodynamic limit of Wigner-Poisson kinetic theory: Revisited

    NASA Astrophysics Data System (ADS)

    Akbari-Moghanjoughi, M.

    2015-02-01

    In this paper, we revisit the hydrodynamic limit of the Langmuir wave dispersion relation based on the Wigner-Poisson model in connection with that obtained directly from the original Lindhard dielectric function based on the random-phase-approximation. It is observed that the (fourth-order) expansion of the exact Lindhard dielectric constant correctly reduces to the hydrodynamic dispersion relation with an additional term of fourth-order, beside that caused by the quantum diffraction effect. It is also revealed that the generalized Lindhard dielectric theory accounts for the recently discovered Shukla-Eliasson attractive potential (SEAP). However, the expansion of the exact Lindhard static dielectric function leads to a k4 term of different magnitude than that obtained from the linearized quantum hydrodynamics model. It is shown that a correction factor of 1/9 should be included in the term arising from the quantum Bohm potential of the momentum balance equation in fluid model in order for a correct plasma dielectric response treatment. Finally, it is observed that the long-range oscillatory screening potential (Friedel oscillations) of type cos ( 2 k F r ) / r 3 , which is a consequence of the divergence of the dielectric function at point k = 2kF in a quantum plasma, arises due to the finiteness of the Fermi-wavenumber and is smeared out in the limit of very high electron number-densities, typical of white dwarfs and neutron stars. In the very low electron number-density regime, typical of semiconductors and metals, where the Friedel oscillation wavelength becomes much larger compared to the interparticle distances, the SEAP appears with a much deeper potential valley. It is remarked that the fourth-order approximate Lindhard dielectric constant approaches that of the linearized quantum hydrodynamic in the limit if very high electron number-density. By evaluation of the imaginary part of the Lindhard dielectric function, it is shown that the Landau-damping region in ?-k plane increases dramatically by increase of the electron number-density.

  2. 7/1/09 7:49 PMSage Worksheet: Archimedes Revisited Page 1 of 3http://localhost:8000/home/admin/80/print

    E-print Network

    Landweber, Gregory D.

    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

  3. Visual-motor deficits relate to altered gray and white matter in young adults born preterm with very low birth weight.

    PubMed

    Sripada, Kam; Løhaugen, Gro C; Eikenes, Live; Bjørlykke, Kjerstin M; Håberg, Asta K; Skranes, Jon; Rimol, Lars M

    2015-04-01

    Individuals born preterm and at very low birth weight (birth weight?1500g) are at an increased risk of perinatal brain injury and neurodevelopmental deficits over the long term. This study examined whether this clinical group has more problems with visual-motor integration, motor coordination, and visual perception compared to term-born controls, and related these findings to cortical surface area and thickness and white matter fractional anisotropy. Forty-seven preterm-born very low birth weight individuals and 56 term-born controls were examined at 18-22years of age with a combined cognitive, morphometric MRI, and diffusion tensor imaging evaluation in Trondheim, Norway. Visual-motor skills were evaluated with the Beery-Buktenica Developmental Test of Visual-Motor Integration-V (VMI) copying test and its supplemental tests of motor coordination and visual perception. 3D T1-weighted MPRAGE images and diffusion tensor imaging were done at 1.5T. Cortical reconstruction generated in FreeSurfer and voxelwise maps of fractional anisotropy calculated with Tract-Based Spatial Statistics were used to explore the relationship between MRI findings and cognitive results. Very low birth weight individuals had significantly lower scores on the copying and motor coordination tests compared with controls. In the very low birth weight group, VMI scores showed significant positive relationships with cortical surface area in widespread regions, with reductions of the superior temporal gyrus, insula, and medial occipital lobe in conjunction with the posterior ventral temporal lobe. Visual perception scores also showed positive relationships with cortical thickness in the very low birth weight group, primarily in the lateral occipito-temporo-parietal junction, the superior temporal gyrus, insula, and superior parietal regions. In the very low birth weight group, visual-motor performance correlated positively with fractional anisotropy especially in the corpus callosum, inferior fronto-occipital fasciculus bilaterally, and anterior thalamic radiation bilaterally, driven primarily by an increase in radial diffusivity. VMI scores did not demonstrate a significant relationship to cortical surface area, cortical thickness, or diffusion measures in the control group. Our results indicate that visual-motor integration problems persist into adulthood for very low birth weight individuals, which may be due to structural alterations in several specific gray-white matter networks. Visual-motor deficits appear related to reduced surface area of motor and visual cortices and disturbed connectivity in long association tracts containing visual and motor information. We conjecture that these outcomes may be due to perinatal brain injury or aberrant cortical development secondary to injury or due to very preterm birth. PMID:25592994

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

    Microsoft Academic Search

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

    2001-01-01

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

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

    E-print Network

    van Genabith, Josef

    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

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

    E-print Network

    Dewar, Robert L.

    2009-01-01

    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 is not a constant of the motion. How- ever, Dewar [2, 3] showed that the approximation of adia- batic invariance

  7. Long-time behaviour of particles diffusing in strongly disordered medium, revisited

    E-print Network

    Boyer, Edmond

    L-895 Long-time behaviour of particles diffusing in strongly disordered medium, revisited Y. Shapir) Résumé. 2014 On réexamine l'argument heuristique de Lifshitz pour le comportement à longue durée de la diffusion classique dans le régime fortement désordonné. La déviation de la densité à l'origine suit un

  8. Operator entanglement of two-qubit joint unitary operations revisited: Schmidt number approach

    E-print Network

    Xia, Hui-Zhi; Yang, Qing; Yang, Ming; Cao, Zhuo-Liang

    2012-01-01

    Operator entanglement of two-qubit joint unitary operations is revisited. Schmidt number is an important attribute of a two-qubit unitary operation, and may have connection with the entanglement measure of the unitary operator. We found the entanglement measure of two-qubit unitary operators is classified by the Schmidt number of the unitary operators. The exact relation between the operator entanglement and the parameters of the unitary operator is clarified too.

  9. Inverse neutrinoless double beta decay revisited: Neutrinos, Higgs triplets, and a muon collider

    Microsoft Academic Search

    Werner Rodejohann

    2010-01-01

    We revisit the process of inverse neutrinoless double beta decay (e-e--->W-W-) at future linear colliders. The cases of Majorana neutrino and Higgs triplet exchange are considered. We also discuss the processes e-mu--->W-W- and mu-mu--->W-W-, which are motivated by the possibility of muon colliders. For heavy neutrino exchange, we show that masses up to 106 (105)GeV could be probed for ee

  10. Revisiting the Imperial Archive: Jane Eyre, Wide Sargasso Sea, and the Decomposition of Englishness

    Microsoft Academic Search

    Trevor Hope

    2012-01-01

    Returning to the much-noted relationship between Charlotte Brontë's novel Jane Eyre and Jean Rhys's Wide Sargasso Sea, and noting the central role of architectural structures in both texts, this essay analyses the ways in which the later novel 'revisits' and 'reinhabits' its forerunner. It is argued that the symbolic architecture described by the texts is inseparable from the discursive practices

  11. On reduced order identification; revisiting `On some system identification techniques for adaptive filtering'

    Microsoft Academic Search

    H. Fan; M. Nayeri

    1990-01-01

    T. Soderstrom and P. Stoica (1988) have previously discussed three algorithms: the Steiglitz-McBride method (SMM), the recursive gradient method (RGM), and the instrumental variable method (IVM). These adaptive algorithms are revisited. Their stability and convergence points are studied and discussed under a reduced-order framework which is more realistic in a practical situation. It is concluded that no algorithm has compelling

  12. The infrared spectrum of indium in silicon revisited A. Tardella and B. Pajot

    E-print Network

    Paris-Sud XI, Université de

    1789 The infrared spectrum of indium in silicon revisited A. Tardella and B. Pajot Groupe de Le spectre d'absorption de l'indium dans le silicium a été mesuré dans des conditions où l concentration d'indium dans le silicium par une méthode spectroscopique, nous trouvons que l'élargissement par

  13. Type IIP Supernovae as Standard Candles: The SDSS-II Sample Revisited

    Microsoft Academic Search

    Dovi Poznanski; Peter E. Nugent; Alexei V. Filippenko

    2010-01-01

    We revisit the observed correlation between the Hbeta 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-1. Using this correlation, we re-analyze the publicly available sample of SNe II-P compiled by D'Andrea

  14. The Merton Theorem Revisited and Restated: Conservatism and Fascism as Functional Analogues

    Microsoft Academic Search

    Milan Zafirovski

    2010-01-01

    The paper revisits and restates the Merton Theorem of American religious conservatism (Puritanism) and European fascism (Nazism)\\u000a as functional analogues. The original formulation the Merton Theorem identifies and describes them as functional analogues\\u000a in nativism or nationalism through exclusion of and aggression against non-native out-groups. The paper offers an extended\\u000a restatement of the Merton Theorem in which American conservatism and

  15. Revisiting energy-based swing-up control for the Pendubot

    Microsoft Academic Search

    Xin Xin; Seiji Tanaka; Jin-Hua She; Taiga Yamasaki

    2010-01-01

    In this paper, we revisit the energy-based swing-up control for the Pendubot, a two-link underactuated planar robot with a single actuator at the base joint (shoulder). Different from previous energy-based control solutions, we obtain the following results: 1) we provide a bigger control parameter region for achieving the control objective. Specifically, we present a necessary and sufficient condition for avoiding

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  17. The Relationship between R&D and Market Share: The Schumpeterian Hypothesis Revisited and Implications

    Microsoft Academic Search

    Jungho Kim

    Abstract This,paper presents a simple ,model ,to explore the revisited Schumpeterian ,hypothesis concerning the relationship between,R&D expenditure and market share. The paper generalizes existing works in two ways. First, the model includes both process R&D as a cost-reducing investment and product R&D as a quality-enhancing investment. Second, market share in the model depends on the product quality relative to price,

  18. ES42CH04-Janz ARI 31 July 2011 14:9 Ehrlich and Raven Revisited

    E-print Network

    ES42CH04-Janz ARI 31 July 2011 14:9 R E V I E W S IN A D V A N CE Ehrlich and Raven Revisited and Raven presented in their classical paper on the coevolution between butterflies and plants are still ARI 31 July 2011 14:9 INTRODUCTION It is now nearly 50 years since Ehrlich and Raven published

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

    NASA Astrophysics Data System (ADS)

    Barreiro, Luiz Antonio; Medina, Ricardo

    2014-09-01

    Recently, in [7] 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 ? terms of the OSLEEL using open superstring n-point amplitudes in which n is considerably lower than (N+2) (which is the order of the required amplitude to obtain those ? 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 [21], 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 ?? expansions for these amplitudes up to ? 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.

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

    PubMed Central

    2014-01-01

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

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

    PubMed Central

    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

    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

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

    PubMed Central

    Shin, David; Müller, Peter

    2012-01-01

    The structure of ortho-vanillin, C8H8O3, has been revisited with modern methods and at low temperature (100?K). The previous structure [Iwasaki et al. (1976 ?). Acta Cryst. B32, 1264–1266] is confirmed, but geometric precision is improved by an order of magnitude. The C atom of the meth­oxy group lies close to the benzene ring plane, which is the most common geometry for –OMe groups lying ortho to –OH groups on an aromatic ring. The crystal structure displays one intra­molecular O—H?O and three weak inter­molecular C—H?O hydrogen bonds. PMID:22904806

  3. Silent cries, dancing tears: the metapsychology of art revisited/revised.

    PubMed

    Aragno, Anna

    2011-04-01

    Against the backdrop of a broad survey of the literature on applied psychoanalysis, a number of concepts underpinning the metapsychology of art are revisited and revised: sublimation; interrelationships between primary and secondary processes; symbolization; "fantasy"; and "cathexis." Concepts embedded in dichotomous or drive/energic contexts are examined and reformulated in terms of a continuum of semiotic processes. Freudian dream structure is viewed as a biological/natural template for nonrepressive artistic forms of sublimation. The synthesis presented proposes a model of continuous rather than discontinuous processes, in a nonenergic, biosemiotic metatheoretical framework. PMID:21653915

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

    NASA Astrophysics Data System (ADS)

    Carlà, Marcello

    2013-07-01

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

  5. Inverse neutrinoless double beta decay revisited: Neutrinos, Higgs triplets, and a muon collider

    Microsoft Academic Search

    Werner Rodejohann

    2010-01-01

    We revisit the process of inverse neutrinoless double beta decay (e⁻e{sup -â}W⁻W⁻) at future linear colliders. The cases of Majorana neutrino and Higgs triplet exchange are considered. We also discuss the processes e{sup -μ-â}W⁻W⁻ and μ{sup -μ-â}W⁻W⁻, which are motivated by the possibility of muon colliders. For heavy neutrino exchange, we show that masses up to 10⁶ (10⁵) GeV could

  6. Revisiting Valley Development on Martian Volcanoes Using MGS and Odyssey Data

    NASA Technical Reports Server (NTRS)

    Gulick, Virginia C.

    2005-01-01

    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.

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

    PubMed

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

    2014-01-01

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

  8. A parable of oil and water: Revisiting Prince William Sound, four years after

    SciTech Connect

    Keeble, J.

    1993-12-31

    On Good Friday, March 24, 1989, the Exxon oil tanker Valdez foundered on Bligh Reef, spilling 11 million gallons of crude oil into Alaska`s Prince William Sound. To Alaskans, especially fishing people, this was a shocking but not entirely unanticipated event, as there had been several near misses in the twelve years since the opening of oil shipping from Valdez, Alaska. This article revisits Prince William sound to evaluate both the lingering environmental effects and the socio-economic effects of the spill and the huge monetary settlement from the spills.

  9. Investigating Predictors of Visiting, Using, and Revisiting an Online Health-Communication Program: A Longitudinal Study

    PubMed Central

    Crutzen, Rik; De Vries, Hein

    2010-01-01

    Background Online health communication has the potential to reach large audiences, with the additional advantages that it can be operational at all times and that the costs per visitor are low. Furthermore, research shows that Internet-delivered interventions can be effective in changing health behaviors. However, exposure to Internet-delivered health-communication programs is generally low. Research investigating predictors of exposure is needed to be able to effectively disseminate online interventions. Objective In the present study, the authors used a longitudinal design with the aim of identifying demographic, psychological, and behavioral predictors of visiting, using, and revisiting an online program promoting physical activity in the general population. Methods A webpage was created providing the public with information about health and healthy behavior. The website included a “physical activity check,” which consisted of a physical activity computer-tailoring expert system where visitors could check whether their physical activity levels were in line with recommendations. Visitors who consented to participate in the present study (n = 489) filled in a questionnaire that assessed demographics, mode of recruitment, current physical activity levels, and health motivation. Immediately after, participants received tailored feedback concerning their current physical activity levels and completed a questionnaire assessing affective and cognitive user experience, attitude toward being sufficiently physically active, and intention to be sufficiently physically active. Three months later, participants received an email inviting them once more to check whether their physical activity level had changed. Results Analyses of visiting showed that more women (67.5%) than men (32.5%) visited the program. With regard to continued use, native Dutch participants (odds ratio [OR] = 2.81, 95% confidence interval [CI] = 1.16-6.81, P = .02) and participants with a strong motivation to be healthy (OR = 1.46, CI = 1.03-2.07, P = .03) were most likely to continue usage of the program. With regard to revisiting, older participants (OR = 1.04, CI = 1.01-1.06, P = .01) and highly educated participants (OR = 4.69, CI = 1.44-15.22, P = .01) were more likely to revisit the program after three months. In addition, positive affective user experience predicted revisiting (OR = 1.64, CI = 1.12-2.39, P = .01). Conclusions The results suggest that online interventions could specifically target men, young people, immigrant groups, people with a low education, and people with a weak health motivation to increase exposure to these interventions. Furthermore, eliciting positive feelings in visitors may contribute to higher usage rates. PMID:20813716

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  11. Revisiting amorphous organic matter in Kimmeridgian laminites: what is the role of the vulcanization process in the amorphization

    E-print Network

    Gilli, Adrian

    Revisiting amorphous organic matter in Kimmeridgian laminites: what is the role of the vulcanization process in the amorphization of organic matter? M. Pacton,1 N. Fiet2 and G. Gorin1 1 Department-Sedimentology, University Paris XI, Paris, France Introduction Organic geochemistry and palyno- facies are standard methods

  12. We revisit memory hierarchy design viewing memory as an inter-operation communication agent. This perspective leads to

    E-print Network

    Sohi, Guri S.

    Abstract We revisit memory hierarchy design viewing memory as an inter-operation communication by the TVC do not have to be serviced by other parts of the memory hierarchy, e.g., the data cache. The first agent. This perspective leads to the development of novel methods of performing inter-operation memory

  13. #MOLN-D-09-00009 Revisiting the stimulus-secretion coupling in the adrenal medulla: role of gap junction-

    E-print Network

    Boyer, Edmond

    ). The first demonstration of a neuronal control of the release of catecholamines from the adrenal gland comes1 #MOLN-D-09-00009 Revisiting the stimulus-secretion coupling in the adrenal medulla: role of gap. Abstract The current view of stimulation-secretion coupling in adrenal neuroendocrine chromaffin cells

  14. Revisiting Hot Passive Replication Ruben de Juan-Marin, Hendrik Decker and Francesc D. Mu~noz-Escoi

    E-print Network

    Muñoz, Francesc

    Revisiting Hot Passive Replication Rub´en de Juan-Mar´in, Hendrik Decker and Francesc D. Mu Valencia, Spain {rjuan, hendrik, fmunyoz}@iti.upv.es Abstract Passive replication has been extensively of communication synchrony. Therefore, we propose a new, detailed classification of hot passive replication

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

    E-print Network

    Ilic, Marija D.

    production costs cannot be used as baseline for the assessment of market power in electricity markets1 Abstract-- In the context of the ongoing deregulation of the electricity industry, we revisit to show that a generator owner's optimum bid sequence for a centralized auction market can be above

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

    ERIC Educational Resources Information Center

    Catsambis, Sophia; Buttaro, Anthony, Jr.

    2012-01-01

    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…

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

    E-print Network

    Das, Rhiju

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

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

    ERIC Educational Resources Information Center

    Forum for Youth Investment, 2005

    2005-01-01

    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…

  19. International Conference on E-Portfolio Process in Vocational Education-EPVET 2007 REVISITING CNC TRAINING A "VIRTUAL TRAINING CENTRE

    E-print Network

    Aristomenis, Antoniadis

    International Conference on E-Portfolio Process in Vocational Education- EPVET 2007 REVISITING CNC TRAINING ­ A "VIRTUAL TRAINING CENTRE FOR CNC" Mehmet ahin*1 , Nikolaos Bilalis2 , Süleyman Yaldiz1, Technological Educational Institute of Crete, Chania, Greece Abstract CNC Training has been a scope of interest

  20. Revisiting the Perceptron Predictor Again UNIV. OF VIRGINIA DEPT. OF COMPUTER SCIENCE TECH. REPORT CS-2004-28

    E-print Network

    Vintan, Lucian N.

    Revisiting the Perceptron Predictor Again UNIV. OF VIRGINIA DEPT. OF COMPUTER SCIENCE TECH. REPORT perceptron predictor, which merges the concepts behind the gshare and perceptron branch predictors. This is done by fetching the perceptron weights using the exclusive-or of branch addresses and branch history

  1. Adaptive Evolution of Digestive RNASE1 Genes in Leaf-Eating Monkeys Revisited: New Insights from Ten Additional

    E-print Network

    Oregon, University of

    Adaptive Evolution of Digestive RNASE1 Genes in Leaf-Eating Monkeys Revisited: New Insights from it into focus again. Current understanding of Colobine RNASE1 gene evolution of colobine monkeys largely depends University of New York Graduate Center 3 State Key Laboratory of Genetic Resources and Evolution

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

    E-print Network

    Richner, Heinz

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

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

    E-print Network

    Paris-Sud XI, Université de

    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

  4. Floor the Ceil & Ceil the Floor: Revisiting AIMD Evaluation Ashwin Rao, Arnaud Legout, Bruno Cessac, and Walid Dabbous

    E-print Network

    Paris-Sud XI, Université de

    that is known to be fair and efficient in utilizing the network resources. In this pa- per, we revisit. [6]. We show that under realistic conditions the fairness and efficiency of AIMD is sensitive is often used to round the congestion win- dow value because either kernel implementations or protocol

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

    ERIC Educational Resources Information Center

    Schul, James E.

    2011-01-01

    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…

  6. Dental development of the Ta Forest chimpanzees revisited T.M. Smith a,b,*, B.H. Smith c

    E-print Network

    Dental development of the Taï Forest chimpanzees revisited T.M. Smith a,b,*, B.H. Smith c , D Biology, School of Dental Sciences, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4BW an emerging mandibular M1 at death (previously estimated from the maxillary molar as occurring at 4.1 years

  7. 118 J. Opt. Soc. Am. A/Vol. 11, No. 1/January 1994 Revisiting Pentland's estimator of light source direction

    E-print Network

    Chojnacki, Wojtek

    automatically estimating the direction of the "sun" (light source) from a single image. It is shown that, under a technique for automatic recovery of light source direction was made by Pentland.3 In Pentland's estimator118 J. Opt. Soc. Am. A/Vol. 11, No. 1/January 1994 Revisiting Pentland's estimator of light source

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

    E-print Network

    Krubitzer, Leah A.

    2003-01-01

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

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

    E-print Network

    Bilham, Roger

    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

  10. Indirect transitions, free and impurity-bound excitons in gallium phosphide: A revisit with modulation and photoluminescence spectroscopy

    E-print Network

    Woodall, Jerry M.

    with modulation and photoluminescence spectroscopy H. Alawadhi, R. Vogelgesang, A. K. Ramdas, T. P. Chin, and J. M phosphide: A revisit with modulation and photoluminescence spectroscopy H. Alawadhi, R. Vogelgesang, and A-LA, A-TA, A-X . The phonon energies obtained from both piezo-modulation and photoluminescence

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

    E-print Network

    Kucera, Jan

    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

  12. Letter to the Editors The uncinate fasciculus and extraversion in schizotypal

    E-print Network

    in schizophrenia (Gurrera et al., 2000; Kubicki et al., 2002), and some clinical features of schizophrenia may in schizophrenia may also stem from altered brain function (Gurrera et al., 2005b). The present data suggest). In unstructured situations, autonoetic awareness supports the formulation of goals and the behavioral oversight

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

    ERIC Educational Resources Information Center

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

    2011-01-01

    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…

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

    E-print Network

    to and from other components of Broca's "grand limbic lobe." Of note, cingulate gyrus abnormal- ities have with amygdala, nucleus accum- bens, medial dorsal thalamus, and dorsolateral prefrontal cortex, whereas

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

    ERIC Educational Resources Information Center

    Dick, Anthony Steven; Tremblay, Pascale

    2012-01-01

    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…

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

    E-print Network

    the later course of the disease. Published by Elsevier B.V. Keywords: Diffusion tensor imaging Schizophrenia during their first hospitalization), and 15 psychiatrically healthy controls underwent line

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

    PubMed

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

    2014-11-15

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

  18. Revisiting constraints on the (pseudo)conformal universe with Planck data

    NASA Astrophysics Data System (ADS)

    Rubtsov, G. I.; Ramazanov, S. R.

    2015-02-01

    We revisit constraints on the (pseudo)conformal universe from the nonobservation of statistical anisotropy in the Planck data. The quadratic maximal likelihood estimator is applied to the Planck temperature maps at frequencies 143 and 217 GHz as well as their cross-correlation. The strongest constraint is obtained in the scenario of the (pseudo)conformal universe with a long intermediate evolution after conformal symmetry breaking. In terms of the relevant parameter (coupling constant), the limit is h2<0.0013 at 95% C.L. (using the cross estimator). The analogous limit is much weaker in the scenario without the intermediate stage (h2ln H/0 ? <0.52 ) allowing the coupling constant to be of order 1. In the latter case, the non-Gaussianity in the four-point function appears to be a more promising signature.

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

    E-print Network

    Ge-Rui Chen; Yong-Chang Huang

    2015-01-15

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

  20. Nice to kin and nasty to non-kin: revisiting Hamilton's early insights on eusociality

    PubMed Central

    Boomsma, Jacobus J.; d'Ettorre, Patrizia

    2013-01-01

    When helping behaviour is costly, Hamiltonian logic implies that animals need to direct helpful acts towards kin, so that indirect fitness benefits justify the costs. We revisit inferences about nepotism and aggression in Hamilton's 1964 paper to argue that he overestimated the general significance of nepotism, but that other issues that he raised continue to suggest novel research agendas today. We now know that nepotism in eusocial insects is rare, because variation in genetic recognition cues is insufficient. A lower proportion of individuals breeding and larger clutch sizes selecting for a more uniform colony odour may explain this. Irreversible worker sterility can induce both the fiercest possible aggression and the highest likelihood of helping random distant kin, but these Hamiltonian contentions still await large-scale testing in social animals. PMID:24132094

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

    PubMed

    Venkataraghavan, Karthik; Chan, John; Karthik, Sandhya

    2014-01-01

    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

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

    PubMed

    Hartwig, Jochen

    2008-05-01

    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

  3. Revisiting the Prominent Anti-Tumoral Potential of Pre-mNK Cells

    PubMed Central

    Guimont-Desrochers, Fanny; Lesage, Sylvie

    2013-01-01

    Interferon-producing killer dendritic cells (IKDC) were first described for their outstanding anti-tumoral properties. The “IKDC” terminology implied the description of a novel DC subset and initiated a debate on their cellular lineage origin. This debate shifted the focus away from their notable anti-tumoral potential. IKDC were recently redefined as precursors to mature NK (mNK) cells and consequently renamed pre-mNK cells. Importantly, a putative human equivalent of pre-mNK cells was recently associated with improved disease outcome in cancer patients. It is thus timely to revisit the functional attributes as well as the therapeutic potential of pre-mNK cells in line with their newly defined NK-cell precursor function. PMID:24376447

  4. Cancer Stem Cells, Endothelial Progenitors, and Mesenchymal Stem Cells: “Seed and Soil” Theory Revisited

    PubMed Central

    Lin, Edward H.; Jiang, Yixing; Deng, Yanhong; Lapsiwala, Ritu; Lin, Tongyu; Blau, C. Anthony

    2008-01-01

    Isolation of putative cancer stem cells (CSCs) in various tumors has generated much excitement among researchers who consider these cells the potential “culprits” behind resistance to conventional therapy. Both cancer and cardiovascular disease are believed to be stem cell disorders involving circulating endothelial progenitors (CEPs) and mesenchymal stem cells (MSCs). CD133 and CD44, markers of CSCs in many tumors, also enrich CEPs and MSCs, respectively. We propose an integrated tumorigenesis model that involves all three interdependent stem cell (CSC, CEP, MSC) compartments by revisiting the “seed and soil” model. Developing therapeutics that can effectively target CSCs and spare normal cardiovascular tissue will remain a challenge. Preliminary laboratory and clinical data on monitoring and targeting colon CSCs, using such a modeling system, are discussed. PMID:19259284

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

    E-print Network

    Boudaud, Mathieu; Giesen, Gaëlle; Salati, Pierre

    2014-01-01

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

  6. Revisiting competition in a classic model system using formal links between theory and data.

    PubMed

    Hart, Simon P; Burgin, Jacqueline R; Marshall, Dustin J

    2012-09-01

    Formal links between theory and data are a critical goal for ecology. However, while our current understanding of competition provides the foundation for solving many derived ecological problems, this understanding is fractured because competition theory and data are rarely unified. Conclusions from seminal studies in space-limited benthic marine systems, in particular, have been very influential for our general understanding of competition, but rely on traditional empirical methods with limited inferential power and compatibility with theory. Here we explicitly link mathematical theory with experimental field data to provide a more sophisticated understanding of competition in this classic model system. In contrast to predictions from conceptual models, our estimates of competition coefficients show that a dominant space competitor can be equally affected by interspecific competition with a poor competitor (traditionally defined) as it is by intraspecific competition. More generally, the often-invoked competitive hierarchies and intransitivities in this system might be usefully revisited using more sophisticated empirical and analytical approaches. PMID:23094373

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

    SciTech Connect

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

    2009-01-01

    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.

  8. Revisiting Top-Bottom-Tau Yukawa Unification in Supersymmetric Grand Unified Theories

    E-print Network

    Kazuhiro Tobe; James D. Wells

    2003-01-03

    Third family Yukawa unification, as suggested by minimal SO(10) unification, is revisited in light of recent experimental measurements and theoretical progress. We characterize unification in a semi-model-independent fashion, and conclude that finite $b$ quark mass corrections from superpartners must be nonzero, but much smaller than naively would be expected. We show that a solution that does not require cancellations of dangerously large tanbeta effects in observables implies that scalar superpartner masses should be substantially heavier than the Z scale, and perhaps inaccessible to all currently approved colliders. On the other hand, gauginos must be significantly lighter than the scalars. We demonstrate that a spectrum of anomaly-mediated gaugino masses and heavy scalars works well as a theory compatible with third family Yukawa unification and dark matter observations.

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

    SciTech Connect

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

    2013-06-15

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

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

    E-print Network

    Rainer E. Zimmermann

    2003-04-14

    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.

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

    SciTech Connect

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

    2011-11-01

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

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

    E-print Network

    Borghi, Riccardo

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  14. The role of glycans in immune evasion: the human fetoembryonic defence system hypothesis revisited

    PubMed Central

    Clark, Gary F.

    2014-01-01

    Emerging data suggest that mechanisms to evade the human immune system may be shared by the conceptus, tumour cells, persistent pathogens and viruses. It is therefore timely to revisit the human fetoembryonic defense system (Hu-FEDS) hypothesis that was proposed in two papers in the 1990s. The initial paper suggested that glycoconjugates expressed in the human reproductive system inhibited immune responses directed against gametes and the developing human by employing their carbohydrate sequences as functional groups. These glycoconjugates were proposed to block specific binding interactions and interact with lectins linked to signal transduction pathways that modulated immune cell functions. The second article suggested that aggressive tumour cells and persistent pathogens (HIV, H. pylori, schistosomes) either mimicked or acquired the same carbohydrate functional groups employed in this system to evade immune responses. This subterfuge enabled these pathogens and tumour cells to couple their survival to the human reproductive imperative. The Hu-FEDS model has been repeatedly tested since its inception. Data relevant to this model have also been obtained in other studies. Herein, the Hu-FEDS hypothesis is revisited in the context of these more recent findings. Far more supportive evidence for this model now exists than when it was first proposed, and many of the original predictions have been validated. This type of subterfuge by pathogens and tumour cells likely applies to all sexually reproducing metazoans that must protect their gametes from immune responses. Intervention in these pathological states will likely remain problematic until this system of immune evasion is fully understood and appreciated. PMID:24043694

  15. Thse E2M2 2012/2015 La SSD revisite une approche nouvelle de prise en compte de la

    E-print Network

    Maume-Deschamps, Véronique

    /2015 ______________________________________________________________________________________ __________ La SSD revisitée ­ une approche nouvelle de prise en compte de la variabilité interspécifique pour la des espèces (SSD) est une des clés de voute de l'évaluation du risque en écotoxicologie aujourd'approche SSD est que les sensibilités d'un ensemble d'espèces à un contaminant peuvent être décrites par une

  16. Revisit to Grad's Closure and Development of Physically Motivated Closure for Phenomenological High-Order Moment Model

    SciTech Connect

    Myong, R. S.; Nagdewe, S. P. [Dept. of Mechanical and Aerospace Engineering and Research Center for Aircraft Parts Technology, Gyeongsang National University, Jinju, Gyeongnam 660-701 (Korea, Republic of)

    2011-05-20

    The Grad's closure for the high-order moment equation is revisited and, by extending his theory, a physically motivated closure is developed for the one-dimensional velocity shear gas flow. The closure is based on the physical argument of the relative importance of various terms appearing in the moment equation. Also, the closure is derived such that the resulting theory may be inclusive of the well established linear theory (Navier-Stokes-Fourier) as limiting case near local thermal equilibrium.

  17. Cyclotron resonance revisited Department of Physics, University of California, San Diego, La Jolla, CA 92093, U.S.A.

    E-print Network

    Paris-Sud XI, Université de

    2613 Cyclotron resonance revisited H. Suhl Department of Physics, University of California, San expériences de résonance cyclotron dans les métaux ont été effectuées dans le passé sur des signaux de faible'observation d'effets spécifiquement non linéaires, y compris le chaos, sont dérivées. Abstract. 2014 Cyclotron

  18. The 1995 Kozani-Grevena (northern Greece) earthquake revisited: an improved faulting model from synthetic aperture radar interferometry

    Microsoft Academic Search

    Alexis Rigo; Jean-Bernard de Chabalier; Bertrand Meyer; Rolando Armijo

    2004-01-01

    Previously, geodetic data associated with earthquakes have been widely modelled using co-planar rectangular dislocations in an elastic half-space. However, such models appear inadequate when complex geometries such as variations in strike and dip or multiple fault segments are involved. Here we revisit the 1995 Ms= 6.6 Kozani-Grevena earthquake, and use synthetic aperture radar (SAR) interferometric measurements, tectonic observations and seismological

  19. Lorenz Revisited

    Microsoft Academic Search

    David F. Bjorklund; Carlos Hernández Blasi; Virginia A. Periss

    2010-01-01

    Certain characteristics of childhood immaturity (e.g., infantile facial features) may have been favored by natural selection\\u000a to evoke positive feelings in adults. We propose that some aspects of cognitive immaturity might also endear young children\\u000a to adults. In two studies, adults rated expressions of mature and immature thinking attributed to children. Immature thinking\\u000a in which children expressed a supernatural explanation

  20. Siphons, Revisited

    ERIC Educational Resources Information Center

    Richert, Alex; Binder, P. -M.

    2011-01-01

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

  1. Revisiting Differentiation

    ERIC Educational Resources Information Center

    Winebrenner, Susan

    2007-01-01

    With the passage of the "No Child Left Behind Act" (NCLB), the emphasis is for all children to reach proficient levels. Since they already work above this benchmark, the needs of gifted students are often de-emphasized. If teachers define learning as moving forward from the knowledge a student already has, they find that those who are at greatest…

  2. Ortega Revisited.

    ERIC Educational Resources Information Center

    Asheim, Lester

    1982-01-01

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

  3. Bibliophilately Revisited.

    ERIC Educational Resources Information Center

    Nix, Larry T.

    2000-01-01

    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)

  4. PACER revisited

    SciTech Connect

    Moir, R.W.

    1988-11-18

    This paper discusses a modified version of the PACER concept for power and nuclear material production. In the PACER concept, a 20-kt peaceful nuclear explosion is contained in a cavity about 200 m in diameter, filled with 200 atom of 500/degree/C steam. Energy from the explosion is used to produce power, and the neutrons are used to produce materials such as STTU. The present idea is to modify the PACER concept in three ways to improve the practicality, predictability, and safety of power production from this technology and thus improve public acceptance of this power source. These improvements are (1) line the cavity with steel; (2) replace the steam with molten salt, LiF + BeF2; and (3) reduce the explosive yield to about 2 kt. PACER is the only fusion power concept where the underlying technology of the power source itself is proven and in hand today. The molten-salt shock-suppression and heat transport system and the durability of the underground cavity need demonstration. 10 refs., 3 figs., 1 tab.

  5. PACER revisited

    SciTech Connect

    Moir, R.W.

    1989-03-01

    This paper discusses a modified version of the PACER concept for power and nuclear material production. In the PACER concept, a 20-kt peaceful nuclear explosion is contained in a cavity about 200 m in diameter, filled with 200 atm of 500/sup 0/C steam. Energy from the explosion is used to produce power, and the neutrons are used to produce materials such as /sup 233/U. The present idea is to modify the PACER concept in three ways to improve the practicality, predictability, and safety of power production from this technology and thus improve public acceptance of this power source. These improvements are (1) line the cavity with steel; (2) replace the steam with molten salt, LiF + BeF/sub 2/; and (3) reduce the explosive yield to about 2 kt. PACER is the only fusion power concept where the underlying technology of the power source itself is proven and in hand today. The molten-salt shock-suppression and heat transport system and the durability of the underground cavity need demonstration.

  6. PACER revisited

    Microsoft Academic Search

    Moir

    1989-01-01

    This paper discusses a modified version of the PACER concept for power and nuclear material production. In the PACER concept, a 20-kt peaceful nuclear explosion is contained in a cavity about 200 m in diameter, filled with 200 atm of 500°C steam. Energy from the explosion is used to produce power, and the neutrons are used to produce materials such

  7. PACER revisited

    NASA Astrophysics Data System (ADS)

    Moir, Ralph W.

    1988-11-01

    This paper discusses a modified version of the PACER concept for power and nuclear material production. In the PACER concept, a 20-kt peaceful nuclear explosion is contained in a cavity about 200 m in diameter, filled with 200 atom of 500 C steam. Energy from the explosion is used to produce power, and the neutrons are used to produce materials such as U-233. The present idea is to modify the PACER concept in three ways to improve the practicality, predictability, and safety of power production from this technology and thus improve public acceptance of this power source. These improvements are: (1) line the cavity with steel; (2) replace the steam with molten salt, LiF + BeF2; and (3) reduce the explosive yield to about 2 kt. PACER is the only fusion power concept where the underlying technology of the power source itself is proven and in hand today. The molten-salt shock-suppression and heat transport system and the durability of the underground cavity need demonstration.

  8. PACER revisited

    SciTech Connect

    Moir, R.W.

    1988-10-04

    This paper discusses a modified version of the PACER concept for power and nuclear material production, which changes the working fluid in the cavity from steam to the molten salt, LiF + BeF/sub 2/. In the PACER concept, a 20-kt peaceful nuclear explosion is contained in a cavity about 200 m in diameter, filled with 200 atm of 500/degree/C steam. Energy from the explosion is used to produce power, and the neutrons are used to produce materials such as /sup 233/U, Pu, /sup 60/Co, and T. The present idea is to modify the PACER concept in three ways, to improve the practicality, predictability, and safety of power production from this technology and thus improve public acceptance of this power source. These improvements are line the cavity with steel; replace the steam with molten salt; and reduce the explosive yield to about 2 kt. This concept is the only fusion power concept where the underlying technology is proven and in hand today. 9 refs., 3 figs., 1 tab.

  9. PACER revisited

    Microsoft Academic Search

    Ralph W. Moir

    1988-01-01

    This paper discusses a modified version of the PACER concept for power and nuclear material production. In the PACER concept, a 20-kt peaceful nuclear explosion is contained in a cavity about 200 m in diameter, filled with 200 atom of 500 C steam. Energy from the explosion is used to produce power, and the neutrons are used to produce materials

  10. Wegener revisited

    NASA Astrophysics Data System (ADS)

    Girdler, R. W.

    In his reply to the comment by Marotzke and Adcroft that “The connection between Mediterranean salinity and Ice Age initiation is only postulated but not substantiated through quantitative reasoning supported by data,” (Eos, Nov. 11, 1997, p. 507) R. G. Johnson states, “By these standards Alfred Wegener's ‘outlandish’ continental drift hypothesis would never have been published.”This is grossly unfair to Wegener. If welook at any edition of Wegener's famous book The Origin of Continents and Oceans, we find a large array of arguments supported by geodetic, geophysical, geological, paleontological, biological, and paleoclimatic data. Indeed, it is a remarkable example supporting Marotzke and Adcroft's comments! What we should be pondering is: Why did the scientific establishment reject such a large amount of evidence for so long?

  11. Speechreading Revisited

    ERIC Educational Resources Information Center

    Woll, Bencie

    2012-01-01

    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…

  12. Bronchiectasis revisited.

    PubMed Central

    Lindskog, G. E.

    1986-01-01

    The writer of this retrospective essay witnessed his first open chest operation during the academic year 1928-29 while an intern in general surgery at Lakeside Hospital, Cleveland, Ohio. The operative procedure was probably the first of its kind to be performed at that teaching hospital, and it involved the excision of a mediastinal tumefaction through a median sternotomy. Now, more than fifty-five years and several thousand thoracic operations later, the author recounts the evolution of pulmonary resection, particularly in relation to the therapy of bronchiectasis. The technical obstacles which delayed too long the achievement of reasonably safe and anatomically complete resections of lung are discussed, and the circuitous route trod by pioneering surgeons in their struggle toward that desired goal is described. In addition, some contributions made along the way by members of the faculty at the Yale University School of Medicine to our present knowledge of bronchiectasis--its pathologic anatomy, pathophysiology, and surgical therapy--are summarized briefly. PMID:3515779

  13. Panspermia revisited

    NASA Astrophysics Data System (ADS)

    Horneck, Gerda

    "Panspermia", coined by S. Arrhenius in 1903, suggests that microscopic forms of life, e.g., bacterial spores, can be dispersed in space by the radiation pressure from the Sun thereby seeding life from one planet to another or even beyond our Solar System. Being ignored for almost the rest of the century, the scenario of interplanetary transfer of life has received increased support from recent discoveries, such as the detection of Martian meteorites and the high resistance of microorganisms to outer space conditions. With the aid of space technology and adequate laboratory devices the following decisive step required for viable transfer from one planet to another have been tested: (i) the escape process, i.e. impact ejection into space; (ii) the journey through space over extended periods of time; and (iii) the landing process, i.e. non-destructive deposition of the biological material on another planet. In systematic shock recovery experiments within a pressure range observed in Martian meteorites (5-50 GPa) a vital launch window of 5-40 GPa has been determined for spores of Bacillus subtilis and the lichen Xanthoria elegans, whereas this window was restricted to 5-10 GPa for the endolithic cyanobaterium Chroococcidiopsis. Traveling through space implies exposure to high vacuum, an intense radiation regime of cosmic and solar origin and high temperature fluctuations. In several space experiments the biological efficiency of these different space parameters has been tested: extraterrestrial solar UV radiation has exerted the most deleterious effects to viruses, as well as to bacterial and fungal spores; however shielding against this intense insolation resulted in 70 % survival of B. subtilis spores after spending 6 years in outer space. Lichens survived 2 weeks in space, even without any shielding. The entry process of microorganisms has been recently tested in the STONE facility attached to the heat shield of a reentry capsule. The data support the scenario of "Lithopanspermia", which assumes that impact-expelled rocks serve as interplanetary transfer vehicles for microorganisms colonizing those rocks. Literature: St¨ffler D, Horneck G, Ott S, Hornemann, U, Cockell CS, Moeller R, Meyer C, de Vera J-P, o Fritz J, Artemieva NA,.Experimental evidence for the potential impact ejection of viable microorganisms from Mars and Mars-like planets (2007) Icarus, 186, 585-588. Sancho, L.G., de la Torre, R., Horneck, G., Ascaso, C., de los Rios, A., Pintado, A., Wierzchos, J. and Schuster, M. (2007) Lichens survive in space: Results from the 2005 LICHENS experiment. Astrobiology, 7, 443-454. Mileikowsky C, Cucinotta F, Wilson J W, Gladman B, Horneck G, Lindegren L, Melosh J, Rickman H, Valtonen M, Zheng J Q (2000) Natural transfer of viable microbes In space, Part 1: From Mars to Earth and Earth to Mars, Icarus, 145, 391-427. Nicholson WL, Munakata N, Horneck G, Melosh HJ, and Setlow P (2000) Resistance of Bacillus endospores to extreme terrestrial and extraterrestrial environments, Microb. Mol. Biol. Rev. 64, 548-572.

  14. Pestalotiopsis revisited.

    PubMed

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

    2014-09-01

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

  15. Amyoplasia revisited.

    PubMed

    Hall, Judith G; Aldinger, Kimberly A; Tanaka, Kimi I

    2014-03-01

    Amyoplasia is a specific type and the most common form of arthrogryposis (multiple congenital contractures). It is a clinical diagnosis at this time. Care should be used making the diagnosis because of the implications for recurrence, natural history, associated anomalies, and both etiology and pathogenesis. We reviewed over 600 published reports and 2,500 individual records to identify the 560 individuals reported here. Affected limbs had characteristic positions with fatty-fibrous replacement of muscle. Upper limb involvement was usually characterized by extended elbows. Lower limbs were held in various positions at birth; however, equinovarus positioning of feet was almost always present. Symmetric involvement was common. Among 560 affected individuals, subtypes were identified: four-limb symmetric involvement (331/560 = 55.9%), severe involvement (41/560 = 7.3%), three-limb involvement (27/560 = 4.8%), upper limb only Amyoplasia (ULA; 94/560 = 16.8%), and lower limb only Amyoplasia (LLA; 25/560 = 15.5%). Discordant monozygotic twinning was increased, occurring in 6.6% (37/560; OR 10.9). A variety of additional anomalies were seen, attributed to apparent vascular compromise. Gastrointestinal vascular compromise-type anomalies were present in 9.1% (51/560), trunk muscle defects in another 2.7% (15/560), digit compromise in 12.1% (68/560), constriction rings in 4.3% (24/560), and perinatal long bone fractures in 10.5% (59/560). Although prenatal ultrasound became the standard of care in 1990, only about one quarter of affected pregnancies were diagnosed prenatally since 1990. Amyoplasia appears to be completely sporadic. Novel pathogenetic mechanisms for the congenital anomalies seen in Amyoplasia need to be identified. PMID:24459070

  16. Balloons Revisited

    ERIC Educational Resources Information Center

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

    2012-01-01

    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…

  17. Pestalotiopsis revisited

    PubMed Central

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

    2014-01-01

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

  18. Interpolation Revisited

    Microsoft Academic Search

    Philippe Thévenaz; Thierry Blu; Michael Unser

    2000-01-01

    Abstract—Based on the theory of approximation, this paper presents a unified analysis of interpolation and,resampling techniques. An important issue is the choice of adequate basis functions. We show that, contrary to the common belief, those that perform best are not interpolating. By opposition to traditional interpolation, we call their use generalized interpolation; they involve a prefiltering step when,correctly applied. We

  19. Marijuana Revisited.

    ERIC Educational Resources Information Center

    Archer, James, Jr.; Lopata, Ann

    1979-01-01

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

  20. 1948 revisited

    SciTech Connect

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

    1989-03-01

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

  1. Einstein Revisited

    ERIC Educational Resources Information Center

    Fine, Leonard

    2005-01-01

    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…

  2. Pseudodiagnosticity Revisited

    ERIC Educational Resources Information Center

    Crupi, Vincenzo; Tentori, Katya; Lombardi, Luigi

    2009-01-01

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

  3. Internationalization Revisited

    ERIC Educational Resources Information Center

    Peterson, Patti McGill; Helms, Robin Matross

    2013-01-01

    For the last decade, the American Council on Education (ACE) has charted higher education's progress towards internationalization through its Mapping Internationalization on US Campuses project. Using surveys of US institutions conducted in 2001, 2006, and 2011, the Mapping study examines strategic planning, the curriculum, faculty policies and…

  4. Euthanasia revisited.

    PubMed

    Chao, D V K; Chan, N Y; Chan, W Y

    2002-04-01

    Euthanasia is a debatable issue. It is illegal all over the world. The Netherlands is the only country where euthanasia and physician-assisted suicide are openly practised since the physician performing these acts will not be prosecuted under certain circumstances. There were several court cases and court decisions that affected the development of euthanasia and physician-assisted suicide in individual countries. When a patient asked for euthanasia, it was very important to find out the underlying reasons and make all legal means available to relieve the pain and other distressing symptoms. PMID:11906976

  5. Relaxation revisited

    Microsoft Academic Search

    J. B. Taylor

    2000-01-01

    Relaxation is the result of turbulence in a plasma that behaves essentially as an ideal conducting fluid, but has a small resistivity and viscosity. These small effects are locally enhanced by the turbulence and lead to reconnection of magnetic field lines. This destroys an infinity of topological constraints, leaving only the total magnetic helicity as a valid invariant. The plasma

  6. Relaxation revisited

    NASA Astrophysics Data System (ADS)

    Taylor, J. B.

    2000-05-01

    Relaxation is the result of turbulence in a plasma that behaves essentially as an ideal conducting fluid, but has a small resistivity and viscosity. These small effects are locally enhanced by the turbulence and lead to reconnection of magnetic field lines. This destroys an infinity of topological constraints, leaving only the total magnetic helicity as a valid invariant. The plasma therefore rapidly reaches a specific state of minimum energy. This minimum energy "relaxed state" can be calculated from first principles and has many striking features. These depend on the topology of the system. They include spontaneous field reversal, symmetry-breaking and current limitation in toroidal pinches, and flux generation and flux amplification in Spheromaks. In addition the relaxed states can be controlled and maintained by injection of helicity from an external circuit. These features, and the profiles of the relaxed states themselves, have been verified in many laboratory experiments.

  7. Leukemia revisited

    SciTech Connect

    Cronkite, E P

    1980-01-01

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

  8. Petaluma Revisited

    ERIC Educational Resources Information Center

    Wolff, Anthony

    1975-01-01

    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)

  9. Visibles Revisited

    ERIC Educational Resources Information Center

    Bridger, Mark; Zelevinsky, Andrei

    2005-01-01

    Within the set of points in the plane with integer coordinates, one point is said to be visible from another if no other point in the set lies between them. This study of visibility draws in topics from a wide variety of mathematical areas, including geometry, number theory, probability, and combinatorics.

  10. Chondrosarcomas revisited.

    PubMed

    Mavrogenis, Andreas F; Gambarotti, Marco; Angelini, Andrea; Palmerini, Emanuela; Staals, Eric L; Ruggieri, Pietro; Papagelopoulos, Panayiotis J

    2012-03-01

    Chondrosarcomas are malignant bone tumors with pure hyaline cartilage differentiation; myxoid changes, calcification, or ossification may be present. Several subtypes of chondrosarcomas exist. Behavior patterns vary, ranging from slow-growing nonmetastasizing lesions to aggressive metastasizing sarcomas. Symptoms are usually mild, with duration ranging from several months to years, and usually consist of persistent, dull, aching pain or palpable masses. Radiographic findings include bone expansion with cortical thickening, radiolucent areas with variably distributed punctate or ring-like matrix calcifications, cortical erosion or destruction, endosteal scalloping, and scant or absent periosteal reaction; extension into the soft tissue may be present. Histological differential diagnosis from benign cartilaginous lesions can be achieved by increased cellularity, enlarged plump nuclei, binucleated cells, hyperchromatic nuclear pleomorphism, and permeation of cortical or medullary bone. Atypia is usually mild to moderate; necrosis and mitoses can be seen, particularly in high-grade lesions. Adequate surgery is the mainstay of treatment. High-grade and pelvic chondrosarcomas are best managed with wide resection. Because of the low metastatic potential and low local recurrence rate noted with intralesional surgery, low-grade chondrosarcomas can be treated with curettage (with or without treatment of the defect cavity) with a local adjuvant, such as phenol or cryotherapy. Adjuvant chemotherapy may be considered for mesenchymal and dedifferentiated chondrosarcomas. Radiation therapy can be considered after incomplete resection or if resection is not feasible or would cause unacceptable morbidity. PMID:22385450

  11. Revisiting the \\

    Microsoft Academic Search

    Simon A. B. Schropp

    2007-01-01

    This paper constitutes an attempt to reframe and eventually deflate the ongoing “compliance-vs.-rebalancing” debate which has permeated WTO scholarship for the last 10 years. At face value, this controversy circles around object and purpose of WTO enforcement and the legal nature of dispute panels’ recommendations: Compliance advocates maintain that the objective of WTO enforcement is to induce compliance with DSB

  12. Endosymbiosis Revisited.

    ERIC Educational Resources Information Center

    Tribe, Michael A.

    1988-01-01

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

  13. Brezinaite Revisited

    NASA Astrophysics Data System (ADS)

    Davis, D. E.

    1993-07-01

    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.

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

    PubMed Central

    Madlung, A

    2013-01-01

    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

  15. Complex rupture process of the 2000 Mw 8.1 New Ireland earthquake, A revisit

    NASA Astrophysics Data System (ADS)

    Li, X.; Shao, G.; Ji, C.

    2011-12-01

    The 16 November 2000 Mw 8 New Ireland earthquake is one of the largest strike-slip earthquakes ever recorded. It was followed by one abnormally strong aftershock sequence including one Mw 7.8 event three hours later and another Mw 7.8 a day after. In spite of the fact that the centroid of fault rupture inferred from previous finite fault studies (e.g., Park and Mori, 2007) is 80 or 120 km away from the epicenter, this earthquake excited large local tsunami at Bougainville and Buka islands that locate at about 300 km southeast of the epicenter, in contrast with the nature that the strike-slip motion is generally not efficient in exciting tsunami. It was then proposed that the damage tsunami was caused by the largest aftershock instead (Geist et al., 2005). Here this complex earthquake is revisited by joint investigating the broadband body waves and long period surface waves. Both the directivity analysis using body waves and multiple double couple analysis using long period surface waves captured the second subevent 260-270 km southeast of epicenter. Our preliminary studies indicate that this subevent has a different focal mechanism but compatible moment magnitude as mainshock. It then might be a better candidate to explain the large tsunami at Bougainville and Buka islands.

  16. Iron deficiency in the elderly population, revisited in the hepcidin era

    PubMed Central

    Busti, Fabiana; Campostrini, Natascia; Martinelli, Nicola; Girelli, Domenico

    2014-01-01

    Iron deficiency (ID) is relatively common among the elderly population, contributing substantially to the high prevalence of anemia observed in the last decades of life, which in turn has important implications both on quality of life and on survival. In elderly subjects, ID is often multifactorial, i.e., due to multiple concurring causes, including inadequate dietary intake or absorption, occult bleeding, medications. Moreover, because of the typical multimorbidity of aged people, other conditions leading to anemia frequently coexist and make diagnosis of ID particularly challenging. Treatment of ID is also problematic in elderly, since response to oral iron is often slow, with a substantial fraction of patients showing refractoriness and requiring cumbersome intravenous administration. In the last decade, the discovery of the iron regulatory hormone hepcidin has revolutionized our understanding of iron pathophysiology. In this review, we revisit ID among elderly people in the light of the impressive recent advances on knowledge of iron regulation, and discuss how hepcidin may help in diagnosis and treatment of this common clinical condition. PMID:24795637

  17. Gray and Green Revisited: A Multidisciplinary Perspective of Gardens, Gardening, and the Aging Process

    PubMed Central

    Wright, Scott D.; Wadsworth, Amy Maida

    2014-01-01

    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

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

    PubMed Central

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

    2009-01-01

    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

  19. Substellar Objects in Nearby Young Clusters VII: The substellar mass function revisited

    E-print Network

    Scholz, Aleks; Clark, Paul; Jayawardhana, Ray; Muzic, Koraljka

    2013-01-01

    The abundance of brown dwarfs (BDs) in young clusters is a diagnostic of star formation theory. Here we revisit the issue of determining the substellar initial mass function (IMF), based on a comparison between NGC1333 and IC348, two clusters in the Perseus star-forming region. We derive their mass distributions for a range of model isochrones, varying distances, extinction laws and ages, with comprehensive assessments of the uncertainties. We find that the choice of isochrone and other parameters have significant effects on the results, thus we caution against comparing IMFs obtained using different approaches. For NGC1333, we find that the star/BD ratio R is between 1.9 and 2.4, for all plausible scenarios, consistent with our previous work. For IC348, R is between 2.9 and 4.0, suggesting that previous studies have overestimated this value. Thus, the star forming process generates about 2.5-5 substellar objects per 10 stars. The derived star/BD ratios correspond to a slope of the power-law mass function of ...

  20. The CO/SiO radiative instability in cool star atmospheres revisited

    NASA Astrophysics Data System (ADS)

    Cuntz, M.; Muchmore, D. O.

    1994-09-01

    We revisit the formation of radiative instabilities in cool star atmospheres and compare our results with those given by Muchmore, Nuth, & Stencel. We have considered the combined influence of CO and SiO molecules and have computed models for a grid of effective temperatures and geometrical dilution factors for the stellar radiation. Our results are based on the analysis of the energy balance of gas elements with prescribed thermodynamic properties. Our results show that radiative instabilities are most likely primarily caused by CO, whereas SiO is expected to play only a minor role, except when the CO density is reduced compared to Local Thermodynamic Equilibrium (LTE) values or the CO band can be assumed to be optically thick. The onset of radiative instabilities is expected to be strongly modified when dynamic phenomena such as stochastic shocks are present. Our results provide strong evidence that dust formation can most likely occur via a radiative instability alone. Therefore, we present a revised version of the Muchmore et al. dust formation paradigm, which also considers hydrodynamic cooling. The new paradigm is particularly relevant in cases where dust is formed relatively close to the stellar photosphere.