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Sample records for hemisphere plant disjunctions

  1. Does the Arcto-Tertiary Biogeographic Hypothesis Explain the Disjunct Distribution of Northern Hemisphere Herbaceous Plants? The Case of Meehania (Lamiaceae)

    PubMed Central

    Deng, Tao; Nie, Ze-Long; Drew, Bryan T.; Volis, Sergei; Kim, Changkyun; Xiang, Chun-Lei; Zhang, Jian-Wen; Wang, Yue-Hua; Sun, Hang

    2015-01-01

    Despite considerable progress, many details regarding the evolution of the Arcto-Tertiary flora, including the timing, direction, and relative importance of migration routes in the evolution of woody and herbaceous taxa of the Northern Hemisphere, remain poorly understood. Meehania (Lamiaceae) comprises seven species and five subspecies of annual or perennial herbs, and is one of the few Lamiaceae genera known to have an exclusively disjunct distribution between eastern Asia and eastern North America. We analyzed the phylogeny and biogeographical history of Meehania to explore how the Arcto-Tertiary biogeographic hypothesis and two possible migration routes explain the disjunct distribution of Northern Hemisphere herbaceous plants. Parsimony and Bayesian inference were used for phylogenetic analyses based on five plastid sequences (rbcL, rps16, rpl32-trnH, psbA-trnH, and trnL-F) and two nuclear (ITS and ETS) gene regions. Divergence times and biogeographic inferences were performed using Bayesian methods as implemented in BEAST and S-DIVA, respectively. Analyses including 11 of the 12 known Meehania taxa revealed incongruence between the chloroplast and nuclear trees, particularly in the positions of Glechoma and Meehania cordata, possibly indicating allopolyploidy with chloroplast capture in the late Miocene. Based on nrDNA, Meehania is monophyletic, and the North American species M. cordata is sister to a clade containing the eastern Asian species. The divergence time between the North American M. cordata and the eastern Asian species occurred about 9.81 Mya according to the Bayesian relaxed clock methods applied to the combined nuclear data. Biogeographic analyses suggest a primary role of the Arcto-Tertiary flora in the study taxa distribution, with a northeast Asian origin of Meehania. Our results suggest an Arcto-Tertiary origin of Meehania, with its present distribution most probably being a result of vicariance and southward migrations of populations during

  2. Origin and evolution of the northern hemisphere disjunction in the moss genus Homalothecium (Brachytheciaceae).

    PubMed

    Huttunen, Sanna; Hedenäs, Lars; Ignatov, Michael S; Devos, Nicolas; Vanderpoorten, Alain

    2008-06-01

    Competing hypotheses that rely either on a stepping-stone dispersal via the North Atlantic or the Bering land bridges, or more recent transoceanic dispersal, have been proposed to explain the disjunct distribution of Mediterranean flora in southern Europe and western North America. These hypotheses were tested with molecular dating using a phylogeny of the moss genus Homalothecium based on ITS, atpB-rbcL, and rpl16 sequence data. The monophyly of two main lineages in Western Palearctic (Europe, central Asia and north Africa) and North America is consistent with the ancient vicariance hypothesis. The monophyly of Madeiran H. sericeum accessions supports the recognition of the Macaronesian endemic H. mandonii. A range of absolute rates of molecular evolution documented in land plants was used as probabilistic calibration prior by a Bayesian inference implementing a relaxed-clock model to derive ages for the nodes of interest. Our age estimates for the divergence of the American and Western Palearctic Homalothecium clade (5.7 Ma, IC 3.52-8.26) and the origin of H. mandonii (2.52 Myr IC 0.86-8.25) are not compatible with the ancient vicariance hypothesis. Age estimates suggests that species distributions result from rare instances of dispersal and subsequent sympatric diversification. The calibrated phylogeny indicates that Homalothecium has undergone a fast radiation during the last 4 Myr, which is consistent with the low levels of morphological divergence among sibling species. PMID:21632398

  3. Back to Gondwanaland: can ancient vicariance explain (some) Indian Ocean disjunct plant distributions?

    PubMed

    Pirie, Michael D; Litsios, Glenn; Bellstedt, Dirk U; Salamin, Nicolas; Kissling, Jonathan

    2015-06-01

    Oceans, or other wide expanses of inhospitable environment, interrupt present day distributions of many plant groups. Using molecular dating techniques, generally incorporating fossil evidence, we can estimate when such distributions originated. Numerous dating analyses have recently precipitated a paradigm shift in the general explanations for the phenomenon, away from older geological causes, such as continental drift, in favour of more recent, long-distance dispersal (LDD). For example, the 'Gondwanan vicariance' scenario has been dismissed in various studies of Indian Ocean disjunct distributions. We used the gentian tribe Exaceae to reassess this scenario using molecular dating with minimum (fossil), maximum (geological), secondary (from wider analyses) and hypothesis-driven age constraints. Our results indicate that ancient vicariance cannot be ruled out as an explanation for the early origins of Exaceae across Africa, Madagascar and the Indian subcontinent unless a strong assumption is made about the maximum age of Gentianales. However, both the Gondwanan scenario and the available evidence suggest that there were also several, more recent, intercontinental dispersals during the diversification of the group. PMID:26063747

  4. Back to Gondwanaland: can ancient vicariance explain (some) Indian Ocean disjunct plant distributions?

    PubMed Central

    Pirie, Michael D.; Litsios, Glenn; Bellstedt, Dirk U.; Salamin, Nicolas; Kissling, Jonathan

    2015-01-01

    Oceans, or other wide expanses of inhospitable environment, interrupt present day distributions of many plant groups. Using molecular dating techniques, generally incorporating fossil evidence, we can estimate when such distributions originated. Numerous dating analyses have recently precipitated a paradigm shift in the general explanations for the phenomenon, away from older geological causes, such as continental drift, in favour of more recent, long-distance dispersal (LDD). For example, the ‘Gondwanan vicariance’ scenario has been dismissed in various studies of Indian Ocean disjunct distributions. We used the gentian tribe Exaceae to reassess this scenario using molecular dating with minimum (fossil), maximum (geological), secondary (from wider analyses) and hypothesis-driven age constraints. Our results indicate that ancient vicariance cannot be ruled out as an explanation for the early origins of Exaceae across Africa, Madagascar and the Indian subcontinent unless a strong assumption is made about the maximum age of Gentianales. However, both the Gondwanan scenario and the available evidence suggest that there were also several, more recent, intercontinental dispersals during the diversification of the group. PMID:26063747

  5. Early signs of range disjunction of submountainous plant species: an unexplored consequence of future and contemporary climate changes.

    PubMed

    Kuhn, Emilien; Lenoir, Jonathan; Piedallu, Christian; Gégout, Jean-Claude

    2016-06-01

    Poleward and upward species range shifts are the most commonly anticipated and studied consequences of climate warming. However, these global responses to climate change obscure more complex distribution change patterns. We hypothesize that the spatial arrangement of mountain ranges and, consequently, climatic gradients in Europe, will result in range disjunctions. This hypothesis was investigated for submountainous forest plant species at two temporal and spatial scales: (i) under future climate change (between 1950-2000 and 2061-2080 periods) at the European scale and (ii) under contemporary climate change (between 1914-1987 and 1997-2013 periods) at the French scale. We selected 97 submountainous forest plant species occurring in France, among which distribution data across Europe are available for 25 species. By projecting future distribution changes for the 25 submountainous plant species across Europe, we demonstrated that range disjunction is a likely consequence of future climate change. To assess whether it is already taking place, we used a large forest vegetation-plot database covering the entire French territory over 100 years (1914-2013) and found an average decrease in frequency (-0.01 ± 0.004) in lowland areas for the 97 submountainous species - corresponding to a loss of 6% of their historical frequency - along with southward and upward range shifts, suggesting early signs of range disjunctions. Climate-induced range disjunctions should be considered more carefully since they could have dramatic consequences on population genetics and the ability of species to face future climate changes. PMID:26845484

  6. Chloroplast capture and intra- and inter-continental biogeographic diversification in the Asian - New World disjunct plant genus Osmorhiza (Apiaceae).

    PubMed

    Yi, Ting-Shuang; Jin, Gui-Hua; Wen, Jun

    2015-04-01

    Osmorhiza Raf. (Apiaceae) contains about 12 species disjunctly distributed in temperate Asia, and North, Central to South America. Phylogenetic and biogeographic analyses were carried out applying sequences of two nuclear and nine plastid loci from eleven recognized Osmorhiza species. The nuclear ITS and ETS and the plastid data fully resolved the infrageneric relationships, yet the two phylogenies were largely incongruent. Comparisons of nuclear and plastid phylogenies revealed several interspecific chloroplast transfer events in Osmorhiza, one of which involved an extinct or an unsampled lineage. This genus was inferred to have originated in the Old World during the late Miocene (11.02mya, 95% HPD: 9.13-12.93mya), and the crown of the genus was dated to be in the late Miocene (5.51mya, 95% HPD: 2.81-8.37mya). Species of Osmorhiza were inferred to have migrated from the Old World into North America across the Bering land bridge during the late Miocene, and they then diversified in the New World through multiple dispersal and divergence events. The intraspecific amphitropical disjunctions between North and South America, and the eastern and western North American disjunctions within O. berteroi and O. depauperata were hypothesized to be via recent long-distance dispersals most likely facilitated by birds. PMID:25585153

  7. Evolution of the intercontinental disjunctions in six continents in the Ampelopsis clade of the grape family (Vitaceae)

    PubMed Central

    2012-01-01

    Background The Ampelopsis clade (Ampelopsis and its close allies) of the grape family Vitaceae contains ca. 43 species disjunctly distributed in Asia, Europe, North America, South America, Africa, and Australia, and is a rare example to study both the Northern and the Southern Hemisphere intercontinental disjunctions. We reconstruct the temporal and spatial diversification of the Ampelopsis clade to explore the evolutionary processes that have resulted in their intercontinental disjunctions in six continents. Results The Bayesian molecular clock dating and the likelihood ancestral area analyses suggest that the Ampelopsis clade most likely originated in North America with its crown group dated at 41.2 Ma (95% HPD 23.4 - 61.0 Ma) in the middle Eocene. Two independent Laurasian migrations into Eurasia are inferred to have occurred in the early Miocene via the North Atlantic land bridges. The ancestor of the Southern Hemisphere lineage migrated from North America to South America in the early Oligocene. The Gondwanan-like pattern of intercontinental disjunction is best explained by two long-distance dispersals: once from South America to Africa estimated at 30.5 Ma (95% HPD 16.9 - 45.9 Ma), and the other from South America to Australia dated to 19.2 Ma (95% HPD 6.7 - 22.3 Ma). Conclusions The global disjunctions in the Ampelopsis clade are best explained by a diversification model of North American origin, two Laurasian migrations, one migration into South America, and two post-Gondwanan long-distance dispersals. These findings highlight the importance of both vicariance and long distance dispersal in shaping intercontinental disjunctions of flowering plants. PMID:22316163

  8. DISJUNCTIVE NORMAL SHAPE MODELS

    PubMed Central

    Ramesh, Nisha; Mesadi, Fitsum; Cetin, Mujdat; Tasdizen, Tolga

    2016-01-01

    A novel implicit parametric shape model is proposed for segmentation and analysis of medical images. Functions representing the shape of an object can be approximated as a union of N polytopes. Each polytope is obtained by the intersection of M half-spaces. The shape function can be approximated as a disjunction of conjunctions, using the disjunctive normal form. The shape model is initialized using seed points defined by the user. We define a cost function based on the Chan-Vese energy functional. The model is differentiable, hence, gradient based optimization algorithms are used to find the model parameters. PMID:27403233

  9. DISJUNCTIVE KRIGING 3. COKRIGING

    EPA Science Inventory

    The disjunctive kriging (DK) method described in the first paper of this series is extended to account for more than one random function. In the derivation contained herein, two random functions are considered, but this is easily generalized to any number. An example is presented...

  10. DISJUNCTIVE KRIGING PROGRAM FOR TWO DIMENSIONS

    EPA Science Inventory

    The paper describes the disjunctive kriging (DK) method for two dimensional spatially variable properties. A brief mathematical description is given which includes all pertinent equations to obtain an estimated value, disjunctive kriging variance, and conditional probability that...

  11. A Southern Hemisphere origin for campanulid angiosperms, with traces of the break-up of Gondwana

    PubMed Central

    2013-01-01

    Background New powerful biogeographic methods have focused attention on long-standing hypotheses regarding the influence of the break-up of Gondwana on the biogeography of Southern Hemisphere plant groups. Studies to date have often concluded that these groups are too young to have been influenced by these ancient continental movements. Here we examine a much larger and older angiosperm clade, the Campanulidae, and infer its biogeographic history by combining Bayesian divergence time information with a likelihood-based biogeographic model focused on the Gondwanan landmasses. Results Our analyses imply that campanulids likely originated in the middle Albian (~105 Ma), and that a substantial portion of the early evolutionary history of campanulids took place in the Southern Hemisphere, despite their greater species richness in the Northern Hemisphere today. We also discovered several disjunctions that show biogeographic and temporal correspondence with the break-up of Gondwana. Conclusions While it is possible to discern traces of the break-up of Gondwana in clades that are old enough, it will generally be difficult to be confident in continental movement as the prime cause of geographic disjunctions. This follows from the need for the geographic disjunction, the inferred biogeographic scenario, and the dating of the lineage splitting events to be consistent with the causal hypothesis. PMID:23565668

  12. Phylogeographical disjunction in abundant high-dispersal littoral gastropods.

    PubMed

    Waters, J M; King, T M; O'Loughlin, P M; Spencer, H G

    2005-08-01

    Abstract Phylogeographical disjunctions in high-dispersal marine taxa are variously ascribed to palaeogeographical conditions or contemporary ecological factors. Associated biogeographical studies, however, seldom incorporate the sampling design required to confidently discriminate among such competing hypotheses. In the current study, over 7800 gastropod specimens were examined for operculum colour, and 129 specimens genetically, to test ecological and historical biogeographical hypotheses relating to biogeographical disjunction in the Southern Hemisphere, and to southern Australia in particular. Mitochondrial DNA sequence analysis of the high-dispersal intertidal gastropod Nerita atramentosa in southern Australia (88 specimens; 18 localities) revealed an east-west phylogeographical split involving two highly divergent clades (26.0 +/- 1.9%) exhibiting minimal geographical overlap in the southeast. The eastern clade of Nerita atramentosa is also widespread in northern New Zealand (43 specimens, 10 localities), but no significant genetic differentiation is explained by the Tasman Sea, a 2000-km-wide oceanic barrier. Spatial genetic structure was not detected within either clade, consistent with the species' dispersive planktotrophic phase lasting for 5-6 months. Digital analysis of operculum colouration revealed substantial differences between eastern (tan) and western (black) specimens. Genetic analysis and visual inspection of 88 Australian specimens revealed a completely nonrandom association between mtDNA data and operculum colouration. Independent examination of a further 7822 specimens from 14 sites in southern Australia revealed both colour morphs at all localities, but reinforced the phylogeographical data by indicating a marked turnover in colour morph abundance associated with a palaeogeographical barrier: Wilsons Promontory. This sharp biogeographical disjunction is in marked contrast to the species' high dispersal abilities. The genetic similarity of

  13. Gestalt Reasoning with Conjunctions and Disjunctions.

    PubMed

    Dumitru, Magda L; Joergensen, Gitte H

    2016-01-01

    Reasoning, solving mathematical equations, or planning written and spoken sentences all must factor in stimuli perceptual properties. Indeed, thinking processes are inspired by and subsequently fitted to concrete objects and situations. It is therefore reasonable to expect that the mental representations evoked when people solve these seemingly abstract tasks should interact with the properties of the manipulated stimuli. Here, we investigated the mental representations evoked by conjunction and disjunction expressions in language-picture matching tasks. We hypothesised that, if these representations have been derived using key Gestalt principles, reasoners should use perceptual compatibility to gauge the goodness of fit between conjunction/disjunction descriptions (e.g., the purple and/ or the green) and corresponding binary visual displays. Indeed, the results of three experimental studies demonstrate that reasoners associate conjunction descriptions with perceptually-dependent stimuli and disjunction descriptions with perceptually-independent stimuli, where visual dependency status follows the key Gestalt principles of common fate, proximity, and similarity. PMID:26986760

  14. Gestalt Reasoning with Conjunctions and Disjunctions

    PubMed Central

    Dumitru, Magda L.; Joergensen, Gitte H.

    2016-01-01

    Reasoning, solving mathematical equations, or planning written and spoken sentences all must factor in stimuli perceptual properties. Indeed, thinking processes are inspired by and subsequently fitted to concrete objects and situations. It is therefore reasonable to expect that the mental representations evoked when people solve these seemingly abstract tasks should interact with the properties of the manipulated stimuli. Here, we investigated the mental representations evoked by conjunction and disjunction expressions in language-picture matching tasks. We hypothesised that, if these representations have been derived using key Gestalt principles, reasoners should use perceptual compatibility to gauge the goodness of fit between conjunction/disjunction descriptions (e.g., the purple and/ or the green) and corresponding binary visual displays. Indeed, the results of three experimental studies demonstrate that reasoners associate conjunction descriptions with perceptually-dependent stimuli and disjunction descriptions with perceptually-independent stimuli, where visual dependency status follows the key Gestalt principles of common fate, proximity, and similarity. PMID:26986760

  15. Updating knowledge bases with disjunctive information

    SciTech Connect

    Zhang, Yan; Foo, Norman Y.

    1996-12-31

    It is well known that the minimal change principle was widely used in knowledge base updates. However, recent research has shown that conventional minimal change methods, eg. the PMA, are generally problematic for updating knowledge bases with disjunctive information. In this paper, we propose two different approaches to deal with this problem - one is called the minimal change with exceptions (MCE), the other is called the minimal change with maximal disjunctive inclusions (MCD). The first method is syntax-based, while the second is model-theoretic. We show that these two approaches are equivalent for propositional knowledge base updates, and the second method is also appropriate for first order knowledge base updates. We then prove that our new update approaches still satisfy the standard Katsuno and Mendelzon`s update postulates.

  16. Transantarctic disjunctions in Schistochilaceae (Marchantiophyta) explained by early extinction events, post-Gondwanan radiations and palaeoclimatic changes.

    PubMed

    Sun, Yu; He, Xiaolan; Glenny, David

    2014-07-01

    The liverworts are the first diverging land plant group with origins in the Ordovician. The family Schistochilaceae exhibits diverse morphology and widely disjunct geographic ranges within the Southern Hemisphere. The family has been presented as a classic example of Gondwanan biogeographic distribution, with extant species ranges resulting from vicariance events. In this study, we present results that elucidate the origin and diversification of Schistochilaceae. We conducted a comprehensive time-calibrated, molecular-based phylogenetic analysis and different approaches for ancestral range inference of the family. Schistochilaceae is inferred to have originated in the Late Cretaceous, in an ancestral area including southern South America, West Antarctica and New Zealand. Despite a family origin at c. 100Ma, most of the diversification of Schistochilaceae occurred in New Zealand after the 80Ma opening of the Tasman Sea that isolated New Zealand from the rest of Gondwana. Most dispersals were transoceanic. The northward migration of the Schistochilaceae is probably linked with the spread of temperate vascular plant forest ecosystems that have Late Cretaceous southern origins and have maintained suitable environments for the family throughout the Cenozoic. The distribution and biogeographic history of the family is very similar to that of Nothofagaceae. PMID:24680916

  17. Living on the edge: timing of Rand Flora disjunctions congruent with ongoing aridification in Africa

    PubMed Central

    Pokorny, Lisa; Riina, Ricarda; Mairal, Mario; Meseguer, Andrea S.; Culshaw, Victoria; Cendoya, Jon; Serrano, Miguel; Carbajal, Rodrigo; Ortiz, Santiago; Heuertz, Myriam; Sanmartín, Isabel

    2015-01-01

    The Rand Flora is a well-known floristic pattern in which unrelated plant lineages show similar disjunct distributions in the continental margins of Africa and adjacent islands—Macaronesia-northwest Africa, Horn of Africa-Southern Arabia, Eastern Africa, and Southern Africa. These lineages are now separated by environmental barriers such as the arid regions of the Sahara and Kalahari Deserts or the tropical lowlands of Central Africa. Alternative explanations for the Rand Flora pattern range from vicariance and climate-driven extinction of a widespread pan-African flora to independent dispersal events and speciation in situ. To provide a temporal framework for this pattern, we used published data from nuclear and chloroplast DNA to estimate the age of disjunction of 17 lineages that span 12 families and nine orders of angiosperms. We further used these estimates to infer diversification rates for Rand Flora disjunct clades in relation to their higher-level encompassing lineages. Our results indicate that most disjunctions fall within the Miocene and Pliocene periods, coinciding with the onset of a major aridification trend, still ongoing, in Africa. Age of disjunctions seemed to be related to the climatic affinities of each Rand Flora lineage, with sub-humid taxa dated earlier (e.g., Sideroxylon) and those with more xeric affinities (e.g., Campylanthus) diverging later. We did not find support for significant decreases in diversification rates in most groups, with the exception of older subtropical lineages (e.g., Sideroxylon, Hypericum, or Canarina), but some lineages (e.g., Cicer, Campylanthus) showed a long temporal gap between stem and crown ages, suggestive of extinction. In all, the Rand Flora pattern seems to fit the definition of biogeographic pseudocongruence, with the pattern arising at different times in response to the increasing aridity of the African continent, with interspersed periods of humidity allowing range expansions. PMID:25983742

  18. Living on the edge: timing of Rand Flora disjunctions congruent with ongoing aridification in Africa.

    PubMed

    Pokorny, Lisa; Riina, Ricarda; Mairal, Mario; Meseguer, Andrea S; Culshaw, Victoria; Cendoya, Jon; Serrano, Miguel; Carbajal, Rodrigo; Ortiz, Santiago; Heuertz, Myriam; Sanmartín, Isabel

    2015-01-01

    The Rand Flora is a well-known floristic pattern in which unrelated plant lineages show similar disjunct distributions in the continental margins of Africa and adjacent islands-Macaronesia-northwest Africa, Horn of Africa-Southern Arabia, Eastern Africa, and Southern Africa. These lineages are now separated by environmental barriers such as the arid regions of the Sahara and Kalahari Deserts or the tropical lowlands of Central Africa. Alternative explanations for the Rand Flora pattern range from vicariance and climate-driven extinction of a widespread pan-African flora to independent dispersal events and speciation in situ. To provide a temporal framework for this pattern, we used published data from nuclear and chloroplast DNA to estimate the age of disjunction of 17 lineages that span 12 families and nine orders of angiosperms. We further used these estimates to infer diversification rates for Rand Flora disjunct clades in relation to their higher-level encompassing lineages. Our results indicate that most disjunctions fall within the Miocene and Pliocene periods, coinciding with the onset of a major aridification trend, still ongoing, in Africa. Age of disjunctions seemed to be related to the climatic affinities of each Rand Flora lineage, with sub-humid taxa dated earlier (e.g., Sideroxylon) and those with more xeric affinities (e.g., Campylanthus) diverging later. We did not find support for significant decreases in diversification rates in most groups, with the exception of older subtropical lineages (e.g., Sideroxylon, Hypericum, or Canarina), but some lineages (e.g., Cicer, Campylanthus) showed a long temporal gap between stem and crown ages, suggestive of extinction. In all, the Rand Flora pattern seems to fit the definition of biogeographic pseudocongruence, with the pattern arising at different times in response to the increasing aridity of the African continent, with interspersed periods of humidity allowing range expansions. PMID:25983742

  19. First Things First: Order Bias in Deontic Disjunctions

    ERIC Educational Resources Information Center

    Elqayam, Shira; Ohm, Eyvind; St. B. T. Evans, Jonathan; Over, David E.

    2010-01-01

    In this paper we examine the way disjunctive choices work in conversational context. We focus on disjunctive deontic rules, such as "you must either submit an essay or attend an exam". According to the Gricean "maxim of orderliness", a derivative of the "maxim of manner", people should interpret the first-mentioned option as the one preferred by…

  20. Inferring differential evolutionary processes of plant persistence traits in Northern Hemisphere Mediterranean fire-prone ecosystems

    USGS Publications Warehouse

    Pausas, J.G.; Keeley, J.E.; Verdu, M.

    2006-01-01

    1 Resprouting capacity (R) and propagule-persistence (P) are traits that are often considered to have evolved where there are predictable crown fires. Because several indicators suggest a stronger selective pressure for such traits in California than in the Mediterranean Basin, we hypothesize that plant species should have evolved to become R+ and P+ more frequently in California than in the Mediterranean Basin. 2 To test this hypothesis we studied the phylogenetic association between R and P states in both California and the Mediterranean Basin using published molecular phylogenies. 3 The results suggest that R and P evolved differently in the two regions. The occurrence of the states differs significantly between regions for trait P, but not for trait R. The different patterns (towards R+ and P+ in California and towards R+ and P- in the Mediterranean Basin) are reflected in the higher abundance and the wider taxonomic distribution of species with both persistence traits (R+P+ species) in California. 4 The differential acquisition of fire persistence mechanisms at the propagule level (P+) supports the idea that fire selective pressures has been higher in California than in the Mediterranean Basin. 5 Our comparative phylogenetic-informed analysis contributes to an understanding of the differential role of the Quaternary climate in determining fire persistence traits in different Mediterranean-type ecosystems and, thus, to the debate on the evolutionary convergence of traits. ?? 2006 British Ecological Society.

  1. Using constraints to model disjunctions in rule-based reasoning

    SciTech Connect

    Liu, Bing; Jaffar, Joxan

    1996-12-31

    Rule-based systems have long been widely used for building expert systems to perform practical knowledge intensive tasks. One important issue that has not been addressed satisfactorily is the disjunction, and this significantly limits their problem solving power. In this paper, we show that some important types of disjunction can be modeled with Constraint Satisfaction Problem (CSP) techniques, employing their simple representation schemes and efficient algorithms. A key idea is that disjunctions are represented as constraint variables, relations among disjunctions are represented as constraints, and rule chaining is integrated with constraint solving. In this integration, a constraint variable or a constraint is regarded as a special fact, and rules can be written with constraints, and information about constraints. Chaining of rules may trigger constraint propagation, and constraint propagation may cause firing of rules. A prototype system (called CFR) based on this idea has been implemented.

  2. Right Hemisphere Brain Damage

    MedlinePlus

    ... Language and Swallowing / Disorders and Diseases Right Hemisphere Brain Damage [ en Español ] What is right hemisphere brain ... right hemisphere brain damage ? What is right hemisphere brain damage? Right hemisphere brain damage (RHD) is damage ...

  3. Phylogeography of Libanotis buchtormensis (Umbelliferae) in Disjunct Populations along the Deserts in Northwest China

    PubMed Central

    Wang, Ping; Zhang, Xianzhi; Tang, Nan; Liu, Jianjun; Xu, Langran; Wang, Kai

    2016-01-01

    In Northwest China, aridification and desert expansion play significant roles in promoting desert plant diversification and speciation. However, to date, little is known about the effects of the desert barrier on the population structure of montane, non-desert species in the area. In this study, we sequenced chloroplast DNA regions (trnL–trnF and trnS–trnG) and a nuclear gene (rpb2) to investigate the population differentiation and phylogeographical history of Libanotis buchtormensis, a perennial montane species possessing a disjunct distribution at the periphery of the central desert. In total, 23 chloroplast haplotypes and 24 nuclear haplotypes were recovered from the 21 natural populations and six hebarium specimens. Phylogenetic analysis based on the combined plastid and nuclear dataset revealed two distinct lineages of L. buchtormensis, which inhabit the disjunct areas on both sides of the desert zone. The molecular dating analysis indicated that the divergence between the southeastern and the northwestern populations occurred in the middle Pleistocene, concomitantly with the desert expansion. The geographical vicariance likely contributed to the present disjunct distribution of L. buchtormensis across the deserts in Northwest China. Populations in the southeastern region may have migrated from the northwestern region, and seem to be a peripheral distribution of L. buchtormensis. PMID:27442136

  4. Phylogeography of Libanotis buchtormensis (Umbelliferae) in Disjunct Populations along the Deserts in Northwest China.

    PubMed

    Wang, Ping; Zhang, Xianzhi; Tang, Nan; Liu, Jianjun; Xu, Langran; Wang, Kai

    2016-01-01

    In Northwest China, aridification and desert expansion play significant roles in promoting desert plant diversification and speciation. However, to date, little is known about the effects of the desert barrier on the population structure of montane, non-desert species in the area. In this study, we sequenced chloroplast DNA regions (trnL-trnF and trnS-trnG) and a nuclear gene (rpb2) to investigate the population differentiation and phylogeographical history of Libanotis buchtormensis, a perennial montane species possessing a disjunct distribution at the periphery of the central desert. In total, 23 chloroplast haplotypes and 24 nuclear haplotypes were recovered from the 21 natural populations and six hebarium specimens. Phylogenetic analysis based on the combined plastid and nuclear dataset revealed two distinct lineages of L. buchtormensis, which inhabit the disjunct areas on both sides of the desert zone. The molecular dating analysis indicated that the divergence between the southeastern and the northwestern populations occurred in the middle Pleistocene, concomitantly with the desert expansion. The geographical vicariance likely contributed to the present disjunct distribution of L. buchtormensis across the deserts in Northwest China. Populations in the southeastern region may have migrated from the northwestern region, and seem to be a peripheral distribution of L. buchtormensis. PMID:27442136

  5. Post-Boreotropical dispersals explain the pantropical disjunction in Paederia (Rubiaceae)

    PubMed Central

    Nie, Ze-Long; Deng, Tao; Meng, Ying; Sun, Hang; Wen, Jun

    2013-01-01

    Background and Aims Pantropical intercontinental disjunction is a common biogeographical pattern in flowering plants exhibiting a discontinuous distribution primarily in tropical Asia, Africa and the Americas. Only a few plant groups with this pattern have been investigated at the generic level with molecular phylogenetic and biogeographical methods. Paederia (Rubiaceae) is a pantropical genus of 31 species of woody lianas, with the greatest species diversity in continental Asia and Madagascar and only two species from tropical America. The aim of this study was to reconstruct the biogeographical history of Paederia based on phylogenetic analyses to explore how the genus attained its pantropical distribution. Methods Maximum parsimony and Bayesian inference were used for phylogenetic analyses using sequences of five plastid markers (the rbcL gene, rps16 intron, trnT-F region, atpB-rbcL spacer and psbA-trnH spacer). Biogeographical inferences were based on a Bayesian uncorrelated lognormal relaxed molecular clock together with both Bayesian and likelihood ancestral area reconstructions. Key Results The data suggest an early diverged Asian lineage sister to the clade of the remaining species consisting of a predominantly Asian sub-clade and a primarily Malagasy sub-clade. Paederia is inferred to have originated in the Oligocene in tropical continental Asia. It then reached Africa in the early to middle Miocene, most probably via long-distance dispersal across the Indian Ocean. The two Neotropical species are inferred to have derived independently in the late Miocene from ancestors of Asia and East Africa, respectively. Conclusions The results demonstrate the importance of post-Boreotropical long-distance dispersals (across three major oceans) in shaping the global pantropical disjunction in some plants, such as Paederia, with small, winged diaspores adapted to long-distance dispersal by various agents including wind, ocean currents or birds. Overland migration is

  6. Remembering in Contradictory Minds: Disjunction Fallacies in Episodic Memory

    ERIC Educational Resources Information Center

    Brainerd, C. J.; Reyna, V. F.; Aydin, C.

    2010-01-01

    Disjunction fallacies have been extensively studied in probability judgment. They should also occur in episodic memory, if remembering a cue's episodic state depends on how its state is described on a memory test (e.g., being described as a target vs. as a distractor). If memory is description-dependent, cues will be remembered as occupying…

  7. Extended abstract: Managing disjunction for practical temporal reasoning

    NASA Technical Reports Server (NTRS)

    Boddy, Mark; Schrag, Bob; Carciofini, Jim

    1992-01-01

    One of the problems that must be dealt with in either a formal or implemented temporal reasoning system is the ambiguity arising from uncertain information. Lack of precise information about when events happen leads to uncertainty regarding the effects of those events. Incomplete information and nonmonotonic inference lead to situations where there is more than one set of possible inferences, even when there is no temporal uncertainty at all. In an implemented system, this ambiguity is a computational problem as well as a semantic one. In this paper, we discuss some of the sources of this ambiguity, which we will treat as explicit disjunction, in the sense that ambiguous information can be interpreted as defining a set of possible inferences. We describe the application of three techniques for managing disjunction in an implementation of Dean's Time Map Manager. Briefly, the disjunction is either: removed by limiting the expressive power of the system, or approximated by a weaker form of representation that subsumes the disjunction. We use a combination of these methods to implement an expressive and efficient temporal reasoning engine that performs sound inference in accordance with a well-defined formal semantics.

  8. Toward A Rhetoric of Visual Fragments: Analyzing Disjunctive Narratives.

    ERIC Educational Resources Information Center

    Schilb, John

    2002-01-01

    Pursues a rhetoric of visual fragments by considering the disjunctive packaging of two particular fictional films: Alfred Hitchcock's 1958 classic "Vertigo" and Christopher Reeve's 1997 adaptation of Alice Elliott Dark's short story, "In the Gloaming." Considers how "Vertigo" offers conflicting stories about the possibility of technologically…

  9. Recombination and non-disjunction: Molecular studies of trisomy 16

    SciTech Connect

    Hassold, T.; Merrill, M.; Adkins, K.

    1994-09-01

    Trisomy 16 is the most common trisomy in humans, occurring in at least 1% of all clinically recognized pregnancies. It is thought to be completely maternally age dependent, thus it provides a useful model for studying the association of increasing maternal age and non-disjunction. We recently initiated a molecular study of non-disjunction of chromosome 16 to determine the parent and meiotic stage of origin of the extra chromosome, and to study the possible association of non-disjunction and aberrant recombination. To date, we have analyzed 62 spontaneous abortions with trisomy 16. All trisomies were maternally-derived and in virtually all the error occurred at meiosis I. Thus, our results are consistent with the idea that a single, maternal age-related non-disjunctional mechanism is responsible for the vast majority of cases of trisomy 16. In studies of genetic recombination, we have used a panel of 25 chromosome 16 markers to examine the frequency and location of crossing-over in the non-disjunctional meioses. Our results indicate a highly significant reduction in recombination, with 20% of cases having no detectable exchanges, 50% a single exchange and 30% two exchanges; no multiple exchange events were identified. This suggests that reduced - but not absent - recombination is the important predisposing factor, since most cases had at least one exchange. Additionally, our data indicate an altered distribution of crossing-over in trisomy 16, as we rarely observed exchanges in the proximal long and short arms. Thus, it may be that, at least for chromosome 16, the association between maternal age and trisomy is due to diminished recombination, particularly in the proximal regions of the chromosome.

  10. Molecular phylogenetics and evolutionary history of sect. Quinquefoliae (Pinus): implications for Northern Hemisphere biogeography.

    PubMed

    Hao, Zhen-Zhen; Liu, Yan-Yan; Nazaire, Mare; Wei, Xiao-Xin; Wang, Xiao-Quan

    2015-06-01

    Climatic changes and tectonic events in the Cenozoic have greatly influenced the evolution and geographic distribution of the temperate flora. Such consequences should be most evident in plant groups that are ancient, widespread, and diverse. As one of the most widespread genera of trees, Pinus provides a good model for investigating the history of species diversification and biogeographic disjunction in the Northern Hemisphere. In this study, we reconstructed the phylogeny and investigated the evolutionary and biogeographic history of sect. Quinquefoliae (Pinus), a species-rich lineage disjunctly distributed in Asia, Europe and North America, based on complete taxon sampling and by using nine DNA fragments from chloroplast (cp), mitochondrial (mt) and nuclear genomes. The monophyly of the three subsections, Krempfianae, Gerardianae, and Strobus, is well-supported by cpDNA and nuclear gene phylogenies. However, neither subsect. Gerardianae nor subsect. Strobus forms a monophyletic group in the mtDNA phylogeny, in which sect. Quinquefoliae was divided into two major clades, one consisting of the North American and northeastern Asian species as well as the European P. peuce of subsect. Strobus, and the other comprising the remaining Eurasian species belonging to three subsections. The significant topological incongruence among the gene trees, in conjunction with divergence time estimation and ancestral area reconstruction, indicates that both ancient and relatively recent introgressive hybridization events occurred in the evolution of sect. Quinquefoliae, particularly in northeastern Asia and northwestern North America. In addition, the phylogenetic analysis suggests that the species of subsect. Strobus from subtropical eastern Asia and neighboring areas may have a single origin, although species non-monophyly is very widespread in the nuclear gene trees. Moreover, our study seems to support a Tethyan origin of sect. Quinquefoliae given the distributions and

  11. A disjunctive analysis of neonatal approach stimulus prepotence.

    PubMed

    Sigman, S E; Schulman, A H

    1976-10-01

    Preliminary results of a disjunctive procedure developed to ascertain the relative attractiveness for domestic chicks of auditory and visual stimuli are promising. A detailed account of the procedure and initial results is presented. Seventy-two Canadian Athens random bred chicks were tested at 24 or 36 h posthatch. A repetitive tone (4 per sec, 50 msec duration, 500 Hz) served as the auditory stimulus, and a flickering light (3.5 flashes per sec, 0.8 foot candle) served as the visual stimulus. An age-dependent change in the attractiveness of auditory and visual stimuli obtained with the disjunctive procedure. No change in stimulus preference obtained when the stimuli were presented individually. PMID:24923647

  12. Limiting inbreeding in disjunct and isolated populations of a woody shrub.

    PubMed

    Sampson, Jane F; Byrne, Margaret; Gibson, Neil; Yates, Colin

    2016-08-01

    Pollen movements and mating patterns are key features that influence population genetic structure. When gene flow is low, small populations are prone to increased genetic drift and inbreeding, but naturally disjunct species may have features that reduce inbreeding and contribute to their persistence despite genetic isolation. Using microsatellite loci, we investigated outcrossing levels, family mating parameters, pollen dispersal, and spatial genetic structure in three populations of Hakea oldfieldii, a fire-sensitive shrub with naturally disjunct, isolated populations prone to reduction in size and extinction following fires. We mapped and genotyped a sample of 102 plants from a large population, and all plants from two smaller populations (28 and 20 individuals), and genotyped 158-210 progeny from each population. We found high outcrossing despite the possibility of geitonogamous pollination, small amounts of biparental inbreeding, a limited number of successful pollen parents within populations, and significant correlated paternity. The number of pollen parents for each seed parent was moderate. There was low but significant spatial genetic structure up to 10 m around plants, but the majority of successful pollen came from outside this area including substantial proportions from distant plants within populations. Seed production varied among seven populations investigated but was not correlated with census population size. We suggest there may be a mechanism to prevent self-pollination in H. oldfieldii and that high outcrossing and pollen dispersal within populations would promote genetic diversity among the relatively small amount of seed stored in the canopy. These features of the mating system would contribute to the persistence of genetically isolated populations prone to fluctuations in size. PMID:27547361

  13. Young dispersal of xerophil Nitraria lineages in intercontinental disjunctions of the Old World.

    PubMed

    Zhang, Ming-Li; Temirbayeva, Kamshat; Sanderson, Stewart C; Chen, Xi

    2015-01-01

    Many cases of intercontinental disjunct distributions of seed plants have been investigated, however few have concerned the continents of Eurasia (mainly Central Asia), Africa, and Australia, especially the xerophytic lineages are lacking. Nitraria (Nitrariaceae) is just one of these xerophytic lineages. Previous Nitraria studies have hypothesized either Africa as the ancient center, with dispersals to Australia and Eurasia, or alternatively Central Asia, due to a concentration of endemism and diversity there. Our findings show eastern Central Asia, i.e. the eastern Tethys, to be the correct place of origin. Dispersal westward to Africa occurred during the late Oligocene to Pliocene, whereas dispersal to Australia from western Central Asia was young since Pliocene 2.61 Ma. Two related tetraploids are indicated to have diversified in eastern Central Asia at approximately 5.89 Ma, while the Australian tetraploid N. billardieri, is an independently derived, recent dispersal from western Central Asia. PMID:26343223

  14. Young dispersal of xerophil Nitraria lineages in intercontinental disjunctions of the Old World

    PubMed Central

    Zhang, Ming-Li; Temirbayeva, Kamshat; Sanderson, Stewart C.; Chen, Xi

    2015-01-01

    Many cases of intercontinental disjunct distributions of seed plants have been investigated, however few have concerned the continents of Eurasia (mainly Central Asia), Africa, and Australia, especially the xerophytic lineages are lacking. Nitraria (Nitrariaceae) is just one of these xerophytic lineages. Previous Nitraria studies have hypothesized either Africa as the ancient center, with dispersals to Australia and Eurasia, or alternatively Central Asia, due to a concentration of endemism and diversity there. Our findings show eastern Central Asia, i.e. the eastern Tethys, to be the correct place of origin. Dispersal westward to Africa occurred during the late Oligocene to Pliocene, whereas dispersal to Australia from western Central Asia was young since Pliocene 2.61 Ma. Two related tetraploids are indicated to have diversified in eastern Central Asia at approximately 5.89 Ma, while the Australian tetraploid N. billardieri, is an independently derived, recent dispersal from western Central Asia. PMID:26343223

  15. The gravitropic and phototropic responses of wheat grown in a space greenhouse prototype with hemispherical planting surface

    NASA Astrophysics Data System (ADS)

    Zyablova, N. V.; Berkovich, Yu. A.; Erokhin, A. N.; Skripnikov, A. Yu.

    2010-11-01

    The time course of gravicurvature of 3-day-old wheat ( Triticum aestivum L., cv. Apogee) coleoptiles and 7-day-old wheat stems were studied in darkness and under red and red-blue light illumination after declination from the vertical at various angles. The experiments showed that the shortest gravitropic curvature corresponded to 30° initial angle of gravistimulation (IAG). The time course became longer as the IAG increased and with plant age. The effects of unilateral red (660 nm) and red-blue light (660 nm; 470 nm) at photosynthetic photon flux (PPF) of 30 μmol m -2 s -1 on the curvature of 3-day-old coleoptiles were evaluated. Red light did not produce phototropic bending of wheat coleoptiles in contrast with red-blue light. The analysis of experimental data showed that the curvature in response to a gravitropic stimulus or to combined gravity-light stimuli were not statistically different. Time course of gravitropic curvature were used to determine the acceptable crop rotation rate around the horizontal axis. Approximation of stem bending to a linear dynamic system described by a first-order aperiodic element with a lag allowed the determination of the dependence of the amplitude of apex oscillations on the rate of horizontal rotation under 1-g conditions. The calculated lowest minimal rotation rate (MRR) minimizing the gravitropic effects on wheat was about 1 revolution per hour (rph). Rotating the plant growth chamber (PGC) at a rate of more than MRR eliminated the effect of gravitropic curvature.

  16. Extensive long-distance pollen dispersal and highly outcrossed mating in historically small and disjunct populations of Acacia woodmaniorum (Fabaceae), a rare banded iron formation endemic

    PubMed Central

    Millar, Melissa A.; Coates, David J.; Byrne, Margaret

    2014-01-01

    Background and Aims Understanding patterns of pollen dispersal and variation in mating systems provides insights into the evolutionary potential of plant species and how historically rare species with small disjunct populations persist over long time frames. This study aims to quantify the role of pollen dispersal and the mating system in maintaining contemporary levels of connectivity and facilitating persistence of small populations of the historically rare Acacia woodmaniorum. Methods Progeny arrays of A. woodmaniorum were genotyped with nine polymorphic microsatellite markers. A low number of fathers contributed to seed within single pods; therefore, sampling to remove bias of correlated paternity was implemented for further analysis. Pollen immigration and mating system parameters were then assessed in eight populations of varying size and degree of isolation. Key Results Pollen immigration into small disjunct populations was extensive (mean minimum estimate 40 % and mean maximum estimate 57 % of progeny) and dispersal occurred over large distances (≤1870m). Pollen immigration resulted in large effective population sizes and was sufficient to ensure adaptive and inbreeding connectivity in small disjunct populations. High outcrossing (mean tm = 0·975) and a lack of apparent inbreeding suggested that a self-incompatibility mechanism is operating. Population parameters, including size and degree of geographic disjunction, were not useful predictors of pollen dispersal or components of the mating system. Conclusions Extensive long-distance pollen dispersal and a highly outcrossed mating system are likely to play a key role in maintaining genetic diversity and limiting negative genetic effects of inbreeding and drift in small disjunct populations of A. woodmaniorum. It is proposed that maintenance of genetic connectivity through habitat and pollinator conservation will be a key factor in the persistence of this and other historically rare species with similar

  17. Children's Interpretation of Disjunction in the Scope of "before": A Comparison of English and Mandarin

    ERIC Educational Resources Information Center

    Notley, Anna; Zhou, Peng; Jensen, Britta; Crain, Stephen

    2012-01-01

    This study investigates three- to five-year-old children's interpretation of disjunction in sentences like "The dog reached the finish line before the turtle or the bunny". English disjunction has a conjunctive interpretation in such sentences ("The dog reached the finish line before the turtle and before the bunny"). This interpretation conforms…

  18. Non-disjunction of an unusual X chromosome.

    PubMed

    Hayata, I; Oshimura, M; Marinello, M J; Bannerman, R M; Sandberg, A A

    1976-08-01

    Because of multiple abnormalities in her children, a young mother was investigated and shown to have a 47,XXX chromosome constitution. Additional C group chromosomes without visible centromeric constrictions were found in a number of cells from the peripheral blood, and using C and Q banding techniques these chromosomes were identified as X chromosomes. Analysis of the banding karyotypes of 300 cells revealed that the acentric X chromosomes had the ability to replicate and that this replication was associated with non-disjunction leading to aneuploid cells. Even though cultured skin cells did not have acentric or extra chromosomes in addition to the triple-X, examination of buccal mucosa cells for the presence of X-bodies suggested that the phenomenon of non-disjunction was present in the epithelial cells of the patient. In addition to the X without a visible centromeric constriction, either acentric D or E chromosomes were found. The data suggest that a functional defect in the cells per se is responsible for the appearance of the acentric chromosomes. PMID:957382

  19. A phylogenetic perspective on the distribution of plant diversity

    PubMed Central

    Donoghue, Michael J.

    2008-01-01

    Phylogenetic studies are revealing that major ecological niches are more conserved through evolutionary history than expected, implying that adaptations to major climate changes have not readily been accomplished in all lineages. Phylogenetic niche conservatism has important consequences for the assembly of both local communities and the regional species pools from which these are drawn. If corridors for movement are available, newly emerging environments will tend to be filled by species that filter in from areas in which the relevant adaptations have already evolved, as opposed to being filled by in situ evolution of these adaptations. Examples include intercontinental disjunctions of tropical plants, the spread of plant lineages around the Northern Hemisphere after the evolution of cold tolerance, and the radiation of northern alpine plants into the Andes. These observations highlight the role of phylogenetic knowledge and historical biogeography in explanations of global biodiversity patterns. They also have implications for the future of biodiversity. PMID:18695216

  20. Tracking the evolutionary history of Cortinarius species in section Calochroi, with transoceanic disjunct distributions

    PubMed Central

    2011-01-01

    Background Cortinarius species in section Calochroi display local, clinal and circumboreal patterns of distribution across the Northern Hemisphere where these ectomycorrhizal fungi occur with host trees throughout their geographical range within a continent, or have disjunct intercontinental distributions, the origins of which are not understood. We inferred evolutionary histories of four species, 1) C. arcuatorum, 2) C. aureofulvus, 3) C. elegantior and 4) C. napus, from populations distributed throughout the Old World, and portions of the New World (Central- and North America) based on genetic variation of 154 haplotype internal transcribed spacer (ITS) sequences from 83 population samples. By describing the population structure of these species across their geographical distribution, we attempt to identify their historical migration and patterns of diversification. Results Models of population structure from nested clade, demographic and coalescent-based analyses revealed genetically differentiated and geographically structured haplotypes in C. arcuatorum and C. elegantior, while C. aureofulvus showed considerably less population structure and C. napus lacked sufficient genetic differentiation to resolve any population structure. Disjunct populations within C. arcuatorum, C. aureofulvus and C. elegantior show little or no morphological differentiation, whereas in C. napus there is a high level of homoplasy and phenotypic plasticity for veil and lamellae colour. The ITS sequences of the type specimens of C. albobrunnoides and C. albobrunnoides var. violaceovelatus were identical to one another and are treated as one species with a wider range of geographic distribution under C. napus. Conclusions Our results indicate that each of the Calochroi species has undergone a relatively independent evolutionary history, hypothesised as follows: 1) a widely distributed ancestral population of C. arcuatorum diverged into distinctive sympatric populations in the New World; 2

  1. [Hemispheric specialisation versus inter-hemispheric communication].

    PubMed

    Belin, C; Faure, S; Mayer, E

    2008-05-01

    The first part of this article covers the main discoveries that led to the concept of hemispheric specialisation, from Egyptian antiquity to present times, through the pivotal XIXth century period that saw the attribution of specific cognitive functions to the left and right hemispheres. Next, this dichotomous conception of cerebral function, attributing a given process to a hemisphere and hypothesising callosal transmission, is discussed in the light of recent studies on language comprehension. Present day knowledge suggesting an alternative to the structuralist view of hemispheric specialisation in the form of dynamic, complementary sharing of labour, and of cooperation through transcortical neural networks, is then considered. Finally, the role of the corpus callosum in interhemispheric communication is briefly covered. An emphasis is placed on the diversity of this structure that is at the origin of highly different functions (fibre size, homotopic vs heterotopic connections). Ultimately, we contrast the view of a corpus callosum serving as an information transmitting channel with that of a fibre tract co-activating the non-engaged hemisphere and preparing it for potential stimulation. In this manner, the corpus callosum minimises disparities in the distribution of attention between the two hemispheres. PMID:18675041

  2. Absence of Cospeciation between the Uncultured Frankia Microsymbionts and the Disjunct Actinorhizal Coriaria Species

    PubMed Central

    Nouioui, Imen; Ghodhbane-Gtari, Faten; Fernandez, Maria P.; Boudabous, Abdellatif; Normand, Philippe; Gtari, Maher

    2014-01-01

    Coriaria is an actinorhizal plant that forms root nodules in symbiosis with nitrogen-fixing actinobacteria of the genus Frankia. This symbiotic association has drawn interest because of the disjunct geographical distribution of Coriaria in four separate areas of the world and in the context of evolutionary relationships between host plants and their uncultured microsymbionts. The evolution of Frankia-Coriaria symbioses was examined from a phylogenetic viewpoint using multiple genetic markers in both bacteria and host-plant partners. Total DNA extracted from root nodules collected from five species: C. myrtifolia, C. arborea, C. nepalensis, C. japonica, and C. microphylla, growing in the Mediterranean area (Morocco and France), New Zealand, Pakistan, Japan, and Mexico, respectively, was used to amplify glnA gene (glutamine synthetase), dnaA gene (chromosome replication initiator), and the nif DK IGS (intergenic spacer between nifD and nifK genes) in Frankia and the matK gene (chloroplast-encoded maturase K) and the intergenic transcribed spacers (18S rRNA-ITS1-5.8S rRNA-ITS2-28S rRNA) in Coriaria species. Phylogenetic reconstruction indicated that the radiations of Frankia strains and Coriaria species are not congruent. The lack of cospeciation between the two symbiotic partners may be explained by host shift at high taxonomic rank together with wind dispersal and/or survival in nonhost rhizosphere. PMID:24864264

  3. Absence of cospeciation between the uncultured Frankia microsymbionts and the disjunct actinorhizal Coriaria species.

    PubMed

    Nouioui, Imen; Ghodhbane-Gtari, Faten; Fernandez, Maria P; Boudabous, Abdellatif; Normand, Philippe; Gtari, Maher

    2014-01-01

    Coriaria is an actinorhizal plant that forms root nodules in symbiosis with nitrogen-fixing actinobacteria of the genus Frankia. This symbiotic association has drawn interest because of the disjunct geographical distribution of Coriaria in four separate areas of the world and in the context of evolutionary relationships between host plants and their uncultured microsymbionts. The evolution of Frankia-Coriaria symbioses was examined from a phylogenetic viewpoint using multiple genetic markers in both bacteria and host-plant partners. Total DNA extracted from root nodules collected from five species: C. myrtifolia, C. arborea, C. nepalensis, C. japonica, and C. microphylla, growing in the Mediterranean area (Morocco and France), New Zealand, Pakistan, Japan, and Mexico, respectively, was used to amplify glnA gene (glutamine synthetase), dnaA gene (chromosome replication initiator), and the nif DK IGS (intergenic spacer between nifD and nifK genes) in Frankia and the matK gene (chloroplast-encoded maturase K) and the intergenic transcribed spacers (18S rRNA-ITS1-5.8S rRNA-ITS2-28S rRNA) in Coriaria species. Phylogenetic reconstruction indicated that the radiations of Frankia strains and Coriaria species are not congruent. The lack of cospeciation between the two symbiotic partners may be explained by host shift at high taxonomic rank together with wind dispersal and/or survival in nonhost rhizosphere. PMID:24864264

  4. What is disjunctive xylem parenchyma? A case study of the African tropical hardwood Okoubaka aubrevillei (Santalaceae).

    PubMed

    Kitin, Peter; Beeckman, Hans; Fujii, Tomoyuki; Funada, Ryo; Noshiro, Shuichi; Abe, Hisashi

    2009-08-01

    The morphological variation and structure-function relationships of xylem parenchyma still remain open to discussion. We analyzed the three-dimensional structure of a poorly known type of xylem parenchyma with disjunctive walls in the tropical hardwood Okoubaka aubrevillei (Santalaceae). Disjunctive cells occurred among the apotracheal parenchyma cells and at connections between axial and ray parenchyma cells. The disjunctive cells were partly detached one from another, but their tubular structures connected them into a continuous network of axial and ray parenchyma. The connecting tubules had thick secondary walls and simple pits with plasmodesmata at the points where one cell contacted a tubule of another cell. The imperforate tracheary elements of the ground tissue were seven times longer than the axial parenchyma strands, a fact that supports a hypothesis that parenchyma cells develop disjunctive walls because they are pulled apart and partly separated during the intrusive growth of fibers. We discuss unresolved details of the formation of disjunctive cell walls and the possible biomechanical advantage of the wood with disjunctive parenchyma: the proportion of tissue that improves mechanical strength is increased by the intrusive elongation of fibers (thick-walled tracheids), whereas the symplastic continuum of the parenchyma is maintained through formation of disjunctive cells. PMID:21628287

  5. Molecular phylogeny and biogeographic diversification of linnaeoideae (caprifoliaceae s. L.) disjunctly distributed in Eurasia, North America and Mexico.

    PubMed

    Wang, Hua-Feng; Landrein, Sven; Dong, Wen-Pan; Nie, Ze-Long; Kondo, Katsuhiko; Funamoto, Tsuneo; Wen, Jun; Zhou, Shi-Liang

    2015-01-01

    Linnaeoideae is a small subfamily of erect or creeping shrubs to small trees in Caprifoliaceae that exhibits a wide disjunct distribution in Eurasia, North America and Mexico. Most taxa of the subfamily occur in eastern Asia and Mexico but the monospecific genus Linnaea has a circumboreal to north temperate distribution. In this study, we conducted phylogenetic and biogeographic analyses for Linnaeoideae and its close relatives based on sequences of the nuclear ribosomal ITS and nine plastid (rbcL, trnS-G, matK, trnL-F, ndhA, trnD-psbM, petB-D, trnL-rpl32 and trnH-psbA) markers. Our results support that Linnaeoideae is monophyletic, consisting of four eastern Asian lineages (Abelia, Diabelia, Dipelta and Kolkwitzia), the Mexican Vesalea, and Linnaea. The Mexican Vesalea was formerly placed in Abelia, but it did not form a clade with the eastern Asian Abelia; instead Vesalea and Linnaea are sisters. The divergence time between the eastern Asian lineages and the Mexican Vesalea plus the Linnaea clade was dated to be 50.86 Ma, with a 95% highest posterior density of 42.8 Ma (middle Eocene) to 60.19 Ma (early Paleocene) using the Bayesian relaxed clock estimation. Reconstructed ancestral areas indicated that the common ancestor of Linnaea plus Vesalea may have been widespread in eastern Asia and Mexico or originated in eastern Asia during the Eocene and likely migrated across continents in the Northern Hemisphere via the North Atlantic Land Bridges or the Bering Land Bridge. The Qinling Mountains of eastern Asia are the modern-day center of diversity of Kolkwitzia-Dipelta-Diabelia clade. The Diabeliaclade became highly diversified in Japan and eastern China. Populations of Diabelia serrata in Japan and eastern China were found to be genetically identical in this study, suggesting a recent disjunction across the East China Sea, following the last glacial event. PMID:25756215

  6. Molecular Phylogeny and Biogeographic Diversification of Linnaeoideae (Caprifoliaceae s. l.) Disjunctly Distributed in Eurasia, North America and Mexico

    PubMed Central

    Wang, Hua-Feng; Landrein, Sven; Dong, Wen-Pan; Nie, Ze-Long; Kondo, Katsuhiko; Funamoto, Tsuneo; Wen, Jun; Zhou, Shi-Liang

    2015-01-01

    Linnaeoideae is a small subfamily of erect or creeping shrubs to small trees in Caprifoliaceae that exhibits a wide disjunct distribution in Eurasia, North America and Mexico. Most taxa of the subfamily occur in eastern Asia and Mexico but the monospecific genus Linnaea has a circumboreal to north temperate distribution. In this study, we conducted phylogenetic and biogeographic analyses for Linnaeoideae and its close relatives based on sequences of the nuclear ribosomal ITS and nine plastid (rbcL, trnS-G, matK, trnL-F, ndhA, trnD-psbM, petB-D, trnL-rpl32 and trnH-psbA) markers. Our results support that Linnaeoideae is monophyletic, consisting of four eastern Asian lineages (Abelia, Diabelia, Dipelta and Kolkwitzia), the Mexican Vesalea, and Linnaea. The Mexican Vesalea was formerly placed in Abelia, but it did not form a clade with the eastern Asian Abelia; instead Vesalea and Linnaea are sisters. The divergence time between the eastern Asian lineages and the Mexican Vesalea plus the Linnaea clade was dated to be 50.86 Ma, with a 95% highest posterior density of 42.8 Ma (middle Eocene) to 60.19 Ma (early Paleocene) using the Bayesian relaxed clock estimation. Reconstructed ancestral areas indicated that the common ancestor of Linnaea plus Vesalea may have been widespread in eastern Asia and Mexico or originated in eastern Asia during the Eocene and likely migrated across continents in the Northern Hemisphere via the North Atlantic Land Bridges or the Bering Land Bridge. The Qinling Mountains of eastern Asia are the modern-day center of diversity of Kolkwitzia-Dipelta-Diabelia clade. The Diabeliaclade became highly diversified in Japan and eastern China. Populations of Diabelia serrata in Japan and eastern China were found to be genetically identical in this study, suggesting a recent disjunction across the East China Sea, following the last glacial event. PMID:25756215

  7. Mechanics of hemispherical electronics

    NASA Astrophysics Data System (ADS)

    Wang, Shuodao; Xiao, Jianliang; Jung, Inhwa; Song, Jizhou; Ko, Heung Cho; Stoykovich, Mark P.; Huang, Yonggang; Hwang, Keh-Chih; Rogers, John A.

    2009-11-01

    A simple analytical model is established for the development of hemisphere electronics, which has many important applications in electronic-eye cameras and related curvilinear systems. The photodetector arrays, made in planar mesh layouts with conventional techniques, are deformed and transferred onto a hemisphere. The model gives accurately the positions of photodetectors on the hemisphere, and has been validated by experiments and finite element analysis. The results also indicate very small residual strains in the photodetectors. The model provides a tool to define a pattern of photodetectors in the planar, as-fabricated layout to yield any desired spatial configuration on the hemisphere.

  8. Comparison of conventional and disjunct eddy covariance fluxes for the validation of a new disjunct sampler design

    NASA Astrophysics Data System (ADS)

    Baghi, R.; Durand, P.; Jambert, C.; Delon, C.; Jarnot, C.; Martin, J.; Ceschia, E.; Keravec, P.; Serca, D.

    2012-12-01

    While Eddy Covariance (EC) is the most direct method to assess trace gas flux at ecosystem scale, it is still limited to a small number of species as it requires fast response analyzers. Alternative approaches have been introduced to relax the constraint on analysis time. An interesting alternative method is the Disjunct Eddy Covariance (DEC) technique, which allows longer integration times (1 s - 10 s) for a small (and therefore acceptable) reduction of flux estimate accuracy. DEC relies on the same assumptions as EC but sub-samples the time series. As a result, it gives more time for concentration measurements between quickly grabbed samples. An innovative design for a disjunct sampling system was developed and tested. The prototype named MEDEE features two pressure regulated reservoirs and chemically inert materials. Built in a 19" rack, this system is suitable for tower based or airplane DEC measurements. It is compatible with most analyzers with relatively slow response (up to 10 s) as it transfers samples continuously at constant pressure. Here we present the results from a validation campaign. DEC and EC measurements of CO2 and water vapor fluxes were performed concurrently with different analyzers over a winter wheat crop. Fluxes measured by the two techniques were in good agreement and encourage the use of this prototype for measurements of species were EC is not applicable. A similar validation campaign has been conducted in June and July 2012 on the French ATR-42 aircraft and will be presented elsewhere. The system is prone to be used in the CHARMEX project on biogenic volatile organic compound (BVOC) emissions in the Mediterranean area, which are known to play a significant role in atmospheric chemistry (e.g. in photo-oxidant pollution): the CHARMEX project.

  9. A time-calibrated phylogeny of southern hemisphere stoneflies: Testing for Gondwanan origins.

    PubMed

    McCulloch, Graham A; Wallis, Graham P; Waters, Jonathan M

    2016-03-01

    For more than two centuries biogeographers have attempted to explain why terrestrial or freshwater lineages have geographic distributions broken by oceans, with these disjunct distributions either attributed to vicariance associated with Gondwanan fragmentation or trans-oceanic dispersal. Stoneflies (order: Plecoptera) are a widespread order of freshwater insects whose poor dispersal ability and intolerance for salt water make them ideal candidates for Gondwanan relicts - taxa whose distribution can be explained by vicariant isolation driven by the breakup of Gondwana. Here we reconstruct the phylogenetic relationships among southern hemisphere stoneflies (5 families; 86 genera) using 2864bp of mitochondrial (COI) and nuclear (18S, H3) DNA, with a calibrated relaxed molecular clock used to estimate the chronology of diversification. Our analysis suggests that largely antitropical stonefly sub-orders, Arctoperlaria (northern hemisphere) and Antarctoperlaria (southern hemisphere), were formed approximately 121Ma (95% prior probability distribution 107-143Ma), which may reflect the vicariant rifting of the supercontinent Pangaea. Subsequently, we infer that a single Arctoperlaria lineage has dispersed into southern hemisphere 76Ma (95% range 65-98Ma). The majority of divergences between South American and Australian stonefly lineages appear to coincide with the opening of Drake Passage around 40Ma, suggesting vicariant isolation of these landmasses may be responsible for these biogeographic disjunctions. In contrast, divergences between New Zealand lineages and their sister taxa appear to post-date vicariant timeframes, implying more recent dispersal events. PMID:26585029

  10. Phylogenetic and phylogeographic evidence for a Pleistocene disjunction between Campanula jacobaea (Cape Verde Islands) and C. balfourii (Socotra).

    PubMed

    Alarcón, Marisa; Roquet, Cristina; García-Fernández, Alfredo; Vargas, Pablo; Aldasoro, Juan José

    2013-12-01

    Our understanding of processes that led to biogeographic disjunct patterns of plant lineages in Macaronesia, North Africa and Socotra remains poor. Here, we study a group of Campanula species distributed across these areas integrating morphological and reproductive traits with phylogenetic and phylogeographic data based on the obtention of sequences for 4 highly variable cpDNA regions and AFLP data. The phylogeny obtained shows a sister relationship between Campanula jacobaea (endemic to Cape Verde Islands) and C. balfourii (endemic to Socotra), thus revealing a striking disjunct pattern (8300 km). These species diverged around 1.0 Mya; AFLP and haplotype data suggest that no genetic interchange has occurred since then. Their closest taxon, C. hypocrateriformis, is endemic to SW Morocco. The archipelagos of Macaronesia and Socotra have probably acted as refugia for North-African species, leading to speciation through isolation. Although C. balfourii has a restricted distribution, its genetic variability suggests that its populations have suffered no bottlenecks. C. jacobaea is also genetically rich and its distribution across Cape Verde Islands seems to have been influenced by the NE-SW trade winds, which may also have favoured the admixture found among the populations of the three southern islands. Floral features of the morphologically hypervariable C. jacobaea were also measured to assess whether the taxon C. bravensis, described for some of the southeast populations of C. jacobaea, corresponds to a different evolutionary entity. We show that morphological variation in C. jacobaea does not correspond to any genetic or geographic group. PMID:23835079

  11. Evolutionary Migration of the Disjunct Salt Cress Eutrema salsugineum (= Thellungiella salsuginea, Brassicaceae) between Asia and North America

    PubMed Central

    Wang, Xin-Yu; Wang, Juan; Sun, Yong-Shuai; Liu, Jian-Quan

    2015-01-01

    Eutrema salsugineum (= Thellungiella salsuginea Brassicaceae), a species growing in highly saline habitats, is a good model for use in salt-stress research. However, its evolutionary migrations and genetic variations within and between disjunct regions from central Asia to northern China and North America remain largely unknown. We examined genetic variations and phylogeographic patterns of this species by sequencing ITS, 9 chloroplast (cp) DNA fragments (4379 bp) and 10 unlinked nuclear loci (6510 bp) of 24 populations across its distributional range. All markers suggested the high genetic poverty of this species and the limited number of genetic variations recovered was congruently partitioned between central Asia, northern China and North America. Further modelling of nuclear population-genetic data based on approximate bayesian computation (ABC) analyses indicated that the long-distance dispersals after the recent origin of E. salsugineum may have occurred from central Asia to the other two regions respectively within 20000 years. The fast demographic expansions should have occurred in northern China in a more recent past. Our study highlights the importance of using ABC analyses and nuclear population genetic data to trace evolutionary migrations of the disjunct distributions of the plants in the recent past. PMID:25970468

  12. Brain Hemispheric Functioning.

    ERIC Educational Resources Information Center

    Roeper Review, 1981

    1981-01-01

    Four articles consider brain hemisphere functioning of gifted students as it relates to gifted programs; alternation of education methodologies; spatial ability as an element of intellectual gifted functioning; and the interaction between hemisphere specialization, imagery, creative imagination, and sex differentiation. (SB)

  13. Reciprocal translocations in man. 3:1 Meiotic disjunction resulting in 47- or 45-chromosome offspring.

    PubMed Central

    Lindenbaum, R H; Bobrow, M

    1975-01-01

    Five cases of chromosome imbalance resulting from 3:1 disjunction of reciprocal translocations are described. A review of the literature suggests this phenomenon is more common than has previously been recognized. Images PMID:123589

  14. Phylogeny and disjunct distribution: evolution of Saintpaulia (Gesneriaceae).

    PubMed

    Möller, M; Cronk, Q C

    1997-12-22

    The molecular phylogeny of African violets (Saintpaulia H. Wendl.), based on ribosomal DNA internal transcribed spacer (ITS) sequences, follows the disjunct biogeography of the genus. Sequence analysis by parsimony of 19 accessions, representing 17 currently recognized Saintpaulia species, resulted in four trees of 182 steps. The first major division is between S. goetzeana, from the Uluguru Mts, Tanzania, and the rest of the genus. The basal position of S. goetzeana, and its putative primitive characters, may indicate an Uluguru origin for Saintpaulia and subsequent colonization of the more northerly mountains. Of the remainder, S. teitensis, from the Teita Hills of Kenya, is sister taxon to the other species (which occur mainly in the Usambara Mts of north-east Tanzania). A group of nine Usambaran species that we call the 'ionantha complex' show minimal ITS genetic differentiation and are also taxonomically critical. Species diversity in the Usambara Mts appears to be the result of rapid, recent (possibly Pleistocene) radiation. This study reveals the limitations of ITS sequences for elucidating the radiation of poorly differentiated species (the ionantha complex). However, the molecular data strongly suggest that conservation of the Uluguru and Teita populations is essential for the protection of the full range of diversity within the genus. PMID:9447739

  15. Similarity-dissimilarity competition in disjunctive classification tasks.

    PubMed

    Mathy, Fabien; Haladjian, Harry H; Laurent, Eric; Goldstone, Robert L

    2013-01-01

    Typical disjunctive artificial classification tasks require participants to sort stimuli according to rules such as "x likes cars only when black and coupe OR white and SUV." For categories like this, increasing the salience of the diagnostic dimensions has two simultaneous effects: increasing the distance between members of the same category and increasing the distance between members of opposite categories. Potentially, these two effects respectively hinder and facilitate classification learning, leading to competing predictions for learning. Increasing saliency may lead to members of the same category to be considered lesssimilar, while the members of separate categories might be considered moredissimilar. This implies a similarity-dissimilarity competition between two basic classification processes. When focusing on sub-category similarity, one would expect more difficult classification when members of the same category become less similar (disregarding the increase of between-category dissimilarity); however, the between-category dissimilarity increase predicts a less difficult classification. Our categorization study suggests that participants rely more on using dissimilarities between opposite categories than finding similarities between sub-categories. We connect our results to rule- and exemplar-based classification models. The pattern of influences of within- and between-category similarities are challenging for simple single-process categorization systems based on rules or exemplars. Instead, our results suggest that either these processes should be integrated in a hybrid model, or that category learning operates by forming clusters within each category. PMID:23403979

  16. Similarity-Dissimilarity Competition in Disjunctive Classification Tasks

    PubMed Central

    Mathy, Fabien; Haladjian, Harry H.; Laurent, Eric; Goldstone, Robert L.

    2013-01-01

    Typical disjunctive artificial classification tasks require participants to sort stimuli according to rules such as “x likes cars only when black and coupe OR white and SUV.” For categories like this, increasing the salience of the diagnostic dimensions has two simultaneous effects: increasing the distance between members of the same category and increasing the distance between members of opposite categories. Potentially, these two effects respectively hinder and facilitate classification learning, leading to competing predictions for learning. Increasing saliency may lead to members of the same category to be considered less similar, while the members of separate categories might be considered more dissimilar. This implies a similarity-dissimilarity competition between two basic classification processes. When focusing on sub-category similarity, one would expect more difficult classification when members of the same category become less similar (disregarding the increase of between-category dissimilarity); however, the between-category dissimilarity increase predicts a less difficult classification. Our categorization study suggests that participants rely more on using dissimilarities between opposite categories than finding similarities between sub-categories. We connect our results to rule- and exemplar-based classification models. The pattern of influences of within- and between-category similarities are challenging for simple single-process categorization systems based on rules or exemplars. Instead, our results suggest that either these processes should be integrated in a hybrid model, or that category learning operates by forming clusters within each category. PMID:23403979

  17. Southern hemisphere observations

    NASA Astrophysics Data System (ADS)

    Orchiston, Wayne

    Because of insurmountable problems associated with absolute dating, the non-literate cultures of the Southern Hemisphere can contribute little to Applied Historical Astronomy, although Maori traditions document a possible supernova dating to the period 1000-1770 AD. In contrast, the abundant nineteenth century solar, planetary, cometary and stellar observational data provided by Southern Hemisphere professional and amateur observatories can serve as an invaluable mine of information for present-day astronomers seeking to incorporate historical data in their investigations.

  18. Hemispherical Laue camera

    DOEpatents

    Li, James C. M.; Chu, Sungnee G.

    1980-01-01

    A hemispherical Laue camera comprises a crystal sample mount for positioning a sample to be analyzed at the center of sphere of a hemispherical, X-radiation sensitive film cassette, a collimator, a stationary or rotating sample mount and a set of standard spherical projection spheres. X-radiation generated from an external source is directed through the collimator to impinge onto the single crystal sample on the stationary mount. The diffracted beam is recorded on the hemispherical X-radiation sensitive film mounted inside the hemispherical film cassette in either transmission or back-reflection geometry. The distances travelled by X-radiation diffracted from the crystal to the hemispherical film are the same for all crystal planes which satisfy Bragg's Law. The recorded diffraction spots or Laue spots on the film thereby preserve both the symmetry information of the crystal structure and the relative intensities which are directly related to the relative structure factors of the crystal orientations. The diffraction pattern on the exposed film is compared with the known diffraction pattern on one of the standard spherical projection spheres for a specific crystal structure to determine the orientation of the crystal sample. By replacing the stationary sample support with a rotating sample mount, the hemispherical Laue camera can be used for crystal structure determination in a manner previously provided in conventional Debye-Scherrer cameras.

  19. Exploring the Formation of a Disjunctive Pattern between Eastern Asia and North America Based on Fossil Evidence from Thuja (Cupressaceae).

    PubMed

    Cui, Yi-Ming; Sun, Bin; Wang, Hai-Feng; Ferguson, David Kay; Wang, Yu-Fei; Li, Cheng-Sen; Yang, Jian; Ma, Qing-Wen

    2015-01-01

    Thuja, a genus of Cupressaceae comprising five extant species, presently occurs in both East Asia (3 species) and North America (2 species) and has a long fossil record from Paleocene to Pleistocene in the Northern Hemisphere. Two distinct hypotheses have been proposed to account for the origin and present distribution of this genus. Here we recognize and describe T. sutchuenensis Franch., a new fossil Thuja from the late Pliocene sediments of Zhangcun, Shanxi, North China, based on detailed comparisons with all living species and other fossil ones, integrate the global fossil records of this genus plotted in a set of paleomaps from different time intervals, which show that Thuja probably first appeared at high latitudes of North America in or before the Paleocene. This genus reached Greenland in the Paleocene, then arrived in eastern Asia in the Miocene via the land connection between East Asia and western North America. In the late Pliocene, it migrated into the interior of China. With the Quaternary cooling and drying, Thuja gradually retreated southwards to form today's disjunctive distribution between East Asia and North America. PMID:26393513

  20. Exploring the Formation of a Disjunctive Pattern between Eastern Asia and North America Based on Fossil Evidence from Thuja (Cupressaceae)

    PubMed Central

    Ferguson, David Kay; Wang, Yu-Fei; Li, Cheng-Sen; Yang, Jian; Ma, Qing-Wen

    2015-01-01

    Thuja, a genus of Cupressaceae comprising five extant species, presently occurs in both East Asia (3 species) and North America (2 species) and has a long fossil record from Paleocene to Pleistocene in the Northern Hemisphere. Two distinct hypotheses have been proposed to account for the origin and present distribution of this genus. Here we recognize and describe T. sutchuenensis Franch., a new fossil Thuja from the late Pliocene sediments of Zhangcun, Shanxi, North China, based on detailed comparisons with all living species and other fossil ones, integrate the global fossil records of this genus plotted in a set of paleomaps from different time intervals, which show that Thuja probably first appeared at high latitudes of North America in or before the Paleocene. This genus reached Greenland in the Paleocene, then arrived in eastern Asia in the Miocene via the land connection between East Asia and western North America. In the late Pliocene, it migrated into the interior of China. With the Quaternary cooling and drying, Thuja gradually retreated southwards to form today’s disjunctive distribution between East Asia and North America. PMID:26393513

  1. Large-scale phylogeography of the disjunct Neotropical tree species Schizolobium parahyba (Fabaceae-Caesalpinioideae).

    PubMed

    Turchetto-Zolet, Andreia C; Cruz, Fernanda; Vendramin, Giovanni G; Simon, Marcelo F; Salgueiro, Fabiano; Margis-Pinheiro, Marcia; Margis, Rogerio

    2012-10-01

    Neotropical rainforests exhibit high levels of endemism and diversity. Although the evolutionary genetics of plant diversification has garnered increased interest, phylogeographic studies of widely distributed species remain scarce. Here we describe chloroplast and nuclear variation patterns in Schizolobium parahyba (Fabaceae), a widespread tree in Neotropical rainforests that harbor two varieties with a disjunct distribution. Chloroplast and nuclear sequence analyses yielded 21 and 4 haplotypes, respectively. Two genetic diversity centers that correlate with the two known varieties were identified: the Southeastern Atlantic forest and the Amazonian basin. In contrast, the populations from southern and northeastern Atlantic forests and Andean-Central American forests exhibited low levels of genetic diversity and divergent haplotypes, likely related to historical processes that impact the flora and fauna in these regions, such as a founder's effect after dispersion and demographic expansion. Phylogeographic and demographic patterns suggest that episodes of genetic isolation and dispersal events have shaped the evolutionary history for this species, and different patterns have guided the evolution of S. parahyba. Moreover, the results of this study suggest that the dry corridor formed by Cerrado and Caatinga ecoregions and the Andean uplift acted as barriers to this species' gene flow, a picture that may be generalized to most of the plant biodiversity tropical woodlands and forests. These results also reinforce the importance of evaluating multiple genetic markers for a more comprehensive understanding of population structure and history. Our results provide insight into the conservation efforts and ongoing work on the genetics of population divergence and speciation in these Neotropical rainforests. PMID:22750114

  2. Multicolor FISH studies of male non-disjunction: Evidence for a paternal age effect

    SciTech Connect

    Griffin, D.K.; Millie, E.A.; Sheean, L.A.

    1994-09-01

    Approximately 5-10% of autosomal trisomies and the majority of sex chromosome aneuploidies are paternally derived, thus paternal non-disjunction is an important contributor to human chromosomal syndromes. We have been using multicolor FISH to screen for aneuploidy in sperm of normal males and to determine whether there is, among individuals or among chromosomes, variation in the likelihood of non-disjunction. Our initial studies based on analysis of 5000 sperm scored per chromosome in nine males identified significant differences in disomy rates for chromosomes 16, 18 and the sex chromosomes. We have now extended those analyses to a new series of 10 donors aged 22 to 45 to confirm or refute our observations of chromosome-specific differences in rates of disomy; to determine if the size of the centromeric (alpha satellite) sequences is related to non-disjunction frequency; and to determine if there is a paternal as well as a maternal age effect on non-disjunction. For these studies, we have used 3 color FISH for chromosomes 18 and the X and Y chromosomes to now score {approximately}20,000 sperm for each of 10 new donors. Our results provide little evidence for an effect of the size of the Y chromosome centromere on the frequency of sex chromosome disomy. However, we have found considerable variation in rates of disomy among individuals and have confirmed significant differences among chromosomes in the likelihood of non-disjunction; i.e., the rate of non-disjunction of the sex chromosomes is 3.5 -4 times greater than that of chromosome 18 and meiosis II errors are significantly more likely for the Y chromosome than for the X chromosome. Specifically, we have identified increases in the frequency of disomy 18 and both meiosis I (XY) and meiosis II (XX and YY) sex chromosome disomy although the effect is only significant for total sex chromosome disomy.

  3. Social Decision Schemes of the Same Dyads and Tetrads on Two Different Disjunctive Tasks. Educational Reports Umea, No. 24.

    ERIC Educational Resources Information Center

    Egerbladh, Thor

    The purposes of this study were: (1) to test several social decision schemes to obtain plausible explanations of different group processes in solving different disjunctive tasks; and (2) to study both dyads and tetrads solving a eureka and a non-eureka disjunctive task. Social decision schemes theory assumes that a group decision is a joint…

  4. Implementation of Boolean functions with a bounded number of zeros by disjunctive normal forms

    NASA Astrophysics Data System (ADS)

    Maximov, Yu. V.

    2013-09-01

    The problem of constructing simple disjunctive normal forms (DNFs) of Boolean functions with a small number of zeros is considered. The problem is of interest in the complexity analysis of Boolean functions and in its applications to data analysis. The method used is a further development of the reduction approach to the construction of DNFs of Boolean functions. A key idea of the reduction method is that a Boolean function is represented as a disjunction of Boolean functions with fewer zeros. In a number of practically important cases, this technique makes it possible to considerably reduce the complexity of DNF implementations of Boolean functions.

  5. Hemispheric lateralization in reasoning.

    PubMed

    Turner, Benjamin O; Marinsek, Nicole; Ryhal, Emily; Miller, Michael B

    2015-11-01

    A growing body of evidence suggests that reasoning in humans relies on a number of related processes whose neural loci are largely lateralized to one hemisphere or the other. A recent review of this evidence concluded that the patterns of lateralization observed are organized according to two complementary tendencies. The left hemisphere attempts to reduce uncertainty by drawing inferences or creating explanations, even at the cost of ignoring conflicting evidence or generating implausible explanations. Conversely, the right hemisphere aims to reduce conflict by rejecting or refining explanations that are no longer tenable in the face of new evidence. In healthy adults, the hemispheres work together to achieve a balance between certainty and consistency, and a wealth of neuropsychological research supports the notion that upsetting this balance results in various failures in reasoning, including delusions. However, support for this model from the neuroimaging literature is mixed. Here, we examine the evidence for this framework from multiple research domains, including an activation likelihood estimation analysis of functional magnetic resonance imaging studies of reasoning. Our results suggest a need to either revise this model as it applies to healthy adults or to develop better tools for assessing lateralization in these individuals. PMID:26426534

  6. Vicariance and dispersal across Baja California in disjunct marine fish populations.

    PubMed

    Bernardi, Giacomo; Findley, Lloyd; Rocha-Olivares, Axayacatl

    2003-07-01

    Population disjunctions, as a first step toward complete allopatry, present an interesting situation to study incipient speciation. The geological formation of the Baja California Peninsula currently divides 19 species of fish into disjunct populations that are found on its Pacific Coast and in the northern part of the Gulf of California (also called the Sea of Cortez), but are absent from the Cape (Cabo San Lucas) region. We studied the genetic makeup of disjunct populations for 12 of these 19 fish species. Phylogeographic patterns for the 12 species can be separated into two major classes: a first group (eight species) showed reciprocal monophyly and high genetic divergence between disjunct populations. A second group (four species) displayed what appeared to be panmictic populations. Population structure between Pacific Coast populations, across the Punta Eugenia biogeographic boundary, was also evaluated. While dispersal potential (inferred by pelagic larval duration) was a poor predictor of population structure between Gulf of California and Pacific populations, we found that population genetic subdivision along the Pacific Coast at Punta Eugenia was always positively correlated with differentiation between Pacific and Gulf of California populations. Vicariant events, ongoing gene flow, and ecological characteristics played essential roles in shaping the population structures observed in this study. PMID:12940364

  7. The compatibility heuristic in non-categorical hypothetical reasoning: inferences between conditionals and disjunctions.

    PubMed

    Espino, Orlando; Byrne, Ruth M J

    2013-11-01

    A new theory explains how people make hypothetical inferences from a premise consistent with several alternatives to a conclusion consistent with several alternatives. The key proposal is that people rely on a heuristic that identifies compatible possibilities. It is tested in 7 experiments that examine inferences between conditionals and disjunctions. Participants accepted inferences between conditionals and inclusive disjunctions when a compatible possibility was immediately available, in their binary judgments that a conclusion followed or not (Experiment 1a) and ternary judgments that included it was not possible to know (Experiment 1b). The compatibility effect was amplified when compatible possibilities were more readily available, e.g., for 'A only if B' conditionals (Experiment 2). It was eliminated when compatible possibilities were not available, e.g., for 'if and only if A B' bi-conditionals and exclusive disjunctions (Experiment 3). The compatibility heuristic occurs even for inferences based on implicit negation e.g., 'A or B, therefore if C D' (Experiment 4), and between universals 'All A's are B's' and disjunctions (Experiment 5a) and universals and conditionals (Experiment 5b). The implications of the results for alternative theories of the cognitive processes underlying hypothetical deductions are discussed. PMID:23968595

  8. The Effects of Concreteness and Negation on the Difficulty of Hypothetical, Disjunctive and Linear Syllogisms.

    ERIC Educational Resources Information Center

    Hample, Dale

    Three studies investigated the effects of concrete versus abstract wording and negative versus positive premises on the difficulty subjects had in solving several kinds of reasoning tasks. Subjects for all three studies were college undergraduates who received booklets containing either hypothetical, disjunctive, or linear syllogisms. Each booklet…

  9. Music, Hemisphere Preference and Imagery.

    ERIC Educational Resources Information Center

    Stratton, Valerie N.; Zalanowski, Annette H.

    Two experiments were conducted to determine a possible relationship between the right hemisphere, music perception, and mental imagery. The first experiment compared two groups of college students, one of which showed a preference for left hemisphere thinking (n=22) and the other a preference for right hemisphere thinking (n=20), in order to test…

  10. Brain Hemisphericity and Developmental Dyslexia

    ERIC Educational Resources Information Center

    Vlachos, Filippos; Andreou, Eleni; Delliou, Afroditi

    2013-01-01

    The present study examined the link between brain hemisphericity and dyslexia in secondary school students, using the Preference Test (PT), a widely used self-report index of preferred hemisphere thinking styles. The hypothesis was that differences would be revealed between the dyslexic group and their peers in hemispheric preference. A total of…

  11. Phylogeography and disjunct distribution in Lychnophora ericoides (Asteraceae), an endangered cerrado shrub species

    PubMed Central

    Collevatti, Rosane Garcia; Rabelo, Suelen Gonçalves; Vieira, Roberto F.

    2009-01-01

    Background and Aims Lychnophora ericoides (Asteraceae) presents disjunct geographical distribution in cerrado rupestre in the south-east and central Brazil. The phylogeography of the species was investigated to understand the origin of the disjunct geographical distribution. Methods Populations in the south and centre of Serra do Espinhaço, south-east Brazil and on ten other localities in Federal District and Goiás in central Brazil were sampled. Analyses were based on the polymorphisms at chloroplast (trnL intron and psbA-trnH intergenic spacer) and nuclear (ITS nrDNA) genomes. From 12 populations, 192 individuals were sequenced. Network analysis, AMOVA and the Mantel test were performed to understand the relationships among haplotypes and population genetic structure. To understand better the origin of disjunct distribution, demographic parameters and time to most recent common ancestor (TMRCA) were estimated using coalescent analyses. Key Results A remarkable differentiation between populations from the south-east and central Brazil was found and no haplotype was shared between these two regions. No significant effect of isolation by distance was detected. Coalescent analyses showed that some populations are shrinking and others are expanding and that gene flow between populations from the south-east and central Brazil was probably negligible. Conclusions The results strongly support that the disjunct distribution of L. ericoides may represent a climatic relict and that long-distance gene flow is unlikely. With an estimated time to most recent common ancestor (TMRCA) dated from approx. 790 655 ± 36 551 years bp (chloroplast) and approx. 623 555 ± 55 769 years bp (ITS), it was hypothesized that the disjunct distribution may be a consequence of an expansion of the geographical distribution favoured by the drier and colder conditions that prevailed in much of Brazil during the Kansan glaciation, followed by the retraction of the distribution due to the

  12. Pre-Holocene Origin for the Coronopus navasii Disjunction: Conservation Implications from Its Long Isolation.

    PubMed

    Martín-Hernanz, Sara; G Fernández de Castro, Alejandro; Moreno-Saiz, Juan Carlos; Valcárcel, Virginia

    2016-01-01

    Integration of unexpected discoveries about charismatic species can disrupt their well-established recovery plans, particularly when this requires coordinate actions among the different governments responsible. The Critically Endangered Coronopus navasii (Brassicaceae) was considered a restricted endemism to a few Mediterranean temporary ponds in a high mountain range of Southeast Spain, until a new group of populations were discovered 500 km North in 2006. Ten years after this finding, its management has not been accommodated due to limited information of the new populations and administrative inertia. In this study, DNA sequences and species distribution models are used to analyse the origin of the C. navasii disjunction as a preliminary step to reassess its recovery plan. Molecular results placed the disjunction during Miocene-Pleistocene (6.30-0.49 Mya, plastid DNA; 1.45-0.03 Mya, ribosomal DNA), which discards a putative human-mediated origin. In fact, the haplotype network and the low gene flow estimated between disjunct areas suggest long-term isolation. Dispersal is the most likely explanation for the disjunction as interpreted from the highly fragmented distribution projected to the past. Particularly, a northward dispersal from Southeast is proposed since C. navasii haplotype network is connected to the sister-group through the southern haplotype. Although the reassessment of C. navasii conservation status is more optimistic under the new extent of occurrence, its long-term survival may be compromised due to the: (1) natural fragmentation and rarity of the species habitat, (2) genetic isolation between the two disjunct areas, and (3) northward shift of suitable areas under future climate change scenarios. Several ex-situ and in-situ conservation measures are proposed for integrating Central East Spanish populations into the on-going recovery plan, which still only contemplates Southeast populations and therefore does not preserve the genetic structure and

  13. Pre-Holocene Origin for the Coronopus navasii Disjunction: Conservation Implications from Its Long Isolation

    PubMed Central

    G. Fernández de Castro, Alejandro; Moreno-Saiz, Juan Carlos; Valcárcel, Virginia

    2016-01-01

    Integration of unexpected discoveries about charismatic species can disrupt their well-established recovery plans, particularly when this requires coordinate actions among the different governments responsible. The Critically Endangered Coronopus navasii (Brassicaceae) was considered a restricted endemism to a few Mediterranean temporary ponds in a high mountain range of Southeast Spain, until a new group of populations were discovered 500 km North in 2006. Ten years after this finding, its management has not been accommodated due to limited information of the new populations and administrative inertia. In this study, DNA sequences and species distribution models are used to analyse the origin of the C. navasii disjunction as a preliminary step to reassess its recovery plan. Molecular results placed the disjunction during Miocene-Pleistocene (6.30–0.49 Mya, plastid DNA; 1.45–0.03 Mya, ribosomal DNA), which discards a putative human-mediated origin. In fact, the haplotype network and the low gene flow estimated between disjunct areas suggest long-term isolation. Dispersal is the most likely explanation for the disjunction as interpreted from the highly fragmented distribution projected to the past. Particularly, a northward dispersal from Southeast is proposed since C. navasii haplotype network is connected to the sister-group through the southern haplotype. Although the reassessment of C. navasii conservation status is more optimistic under the new extent of occurrence, its long-term survival may be compromised due to the: (1) natural fragmentation and rarity of the species habitat, (2) genetic isolation between the two disjunct areas, and (3) northward shift of suitable areas under future climate change scenarios. Several ex-situ and in-situ conservation measures are proposed for integrating Central East Spanish populations into the on-going recovery plan, which still only contemplates Southeast populations and therefore does not preserve the genetic structure

  14. Spatio-temporal history of the disjunct family Tecophilaeaceae: a tale involving the colonization of three Mediterranean-type ecosystems

    PubMed Central

    Buerki, Sven; Manning, John C.; Forest, Félix

    2013-01-01

    Background and Aims Tecophilaeaceae (27 species distributed in eight genera) have a disjunct distribution in California, Chile and southern and tropical mainland Africa. Moreover, although the family mainly occurs in arid ecosystems, it has colonized three Mediterranean-type ecosystems. In this study, the spatio-temporal history of the family is examined using DNA sequence data from six plastid regions. Methods Modern methods in divergence time estimation (BEAST), diversification (LTT and GeoSSE) and biogeography (LAGRANGE) are applied to infer the evolutionary history of Tecophilaeaceae. To take into account dating and phylogenetic uncertainty, the biogeographical inferences were run over a set of dated Bayesian trees and the analyses were constrained according to palaeogeographical evidence. Key Results The analyses showed that the current distribution and diversification of the family were influenced primarily by the break up of Gondwana, separating the family into two main clades, and the establishment of a Mediterranean climate in Chile, coinciding with the radiation of Conanthera. Finally, unlike many other groups, no shifts in diversification rates were observed associated with the dispersals in the Cape region of South Africa. Conclusions Although modest in size, Tecophilaeaceae have a complex spatio-temporal history. The family is now most diverse in arid ecosystems in southern Africa, but is expected to have originated in sub-tropical Africa. It has subsequently colonized Mediterranean-type ecosystems in both the Northern and Southern Hemispheres, but well before the onset of the Mediterranean climate in these regions. Only one lineage, genus Conanthera, has apparently diversified to any extent under the impetus of a Mediterranean climate. PMID:23277471

  15. Triton's Southern Hemisphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This polar projection of Triton's southern hemisphere provides a view of the southern polar cap and bright equatorial fringe. The margin of the cap is scalloped and ranges in latitude from +10 degrees to -30 degrees. The bright fringe is closely associated with the cap's margin; from it, diffuse bright rays extend north-northeast for hundreds of kilometers. The bright fringe probably consists of very fresh nitrogen frost or snow, and the rays consist of bright-fringe materials that were redistributed by north-moving Coriolis-deflected winds.

  16. Using semantic information for processing negation and disjunction in logic programs

    SciTech Connect

    Gaasterland, T. ); Lobo, J. )

    1993-01-01

    There are many applications in which integrity constraints can play an important role. An example is the semantic query optimization method developed by Chakravarthy, Grant, and Minker for definite deductive databases. They use integrity constraints during query processing to prevent the exploration of search space that is bound to fail. In this paper, the authors generalize the semantic query optimization method to apply to negated atoms. The generalized method is referred to as semantic compilation. They show that semantic compilation provides an alternative search space for negative query literals. They also show how semantic compilation can be used to transform a disjunctive database with or without functions and denial constraints without negation into a new disjunctive database that complies with the integrity constraints.

  17. Using semantic information for processing negation and disjunction in logic programs

    SciTech Connect

    Gaasterland, T.; Lobo, J.

    1993-07-01

    There are many applications in which integrity constraints can play an important role. An example is the semantic query optimization method developed by Chakravarthy, Grant, and Minker for definite deductive databases. They use integrity constraints during query processing to prevent the exploration of search space that is bound to fail. In this paper, the authors generalize the semantic query optimization method to apply to negated atoms. The generalized method is referred to as semantic compilation. They show that semantic compilation provides an alternative search space for negative query literals. They also show how semantic compilation can be used to transform a disjunctive database with or without functions and denial constraints without negation into a new disjunctive database that complies with the integrity constraints.

  18. Increased frequency of lymphocytic mitotic non-disjunction in recurrent spontaneous aborters.

    PubMed Central

    Juberg, R C; Knops, J; Mowrey, P N

    1985-01-01

    Hypermodal chromosomal spreads occurred significantly more frequently in lymphocytes from couples with recurrent spontaneous abortion than from comparison populations. Previously, we reported a similarly increased frequency in couples with aneuploid offspring. Considering the frequency of aneuploidy among first trimester spontaneous abortions, we suggest that there may be a sub-population of persons predisposed to non-disjunction among couples with reproductive wastage. PMID:4039006

  19. Dealing with disjunct concentration measurements in eddy covariance applications: a comparison of available approaches

    PubMed Central

    Hörtnagl, Lukas; Clement, Robert; Graus, Martin; Hammerle, Albin; Hansel, Armin; Wohlfahrt, Georg

    2013-01-01

    Using proton transfer reaction mass spectrometry equipped with a quadrupol mass analyser to quantify the biosphere-atmosphere exchange of volatile organic compounds (VOC), concentrations of different VOC are measured sequentially. Depending on how many VOC species are targeted and their respective integration times, each VOC is measured at repeat rates on the order of a few seconds. This represents an order of magnitude longer sample interval compared to the standard eddy covariance (EC) method (5-20 Hz sampling rates). Here we simulate the effect of disjunct sampling on EC flux estimates by decreasing the time resolution of CO2 and H2O concentrations measured at 20 Hz above a temperate mountain grassland in the Austrian Alps. Fluxes for one month are calculated with the standard EC method and compared to fluxes calculated based on the disjunct data (1, 3 and 5 s sampling rates) using the following approaches: i) imputation of missing concentrations based on the nearest neighbouring samples (iDECnn), ii) imputation by linear interpolation (iDECli), and iii) virtual disjunct EC (vDEC), i.e. flux calculation based solely on the disjunct concentrations. It is shown that the two imputation methods result in additional low-pass filtering, longer lag times (as determined with the maximum cross-correlation method) and a flux loss of 3-30 % as compared to the standard EC method. A novel procedure, based on a transfer function approach, which specifically corrects for the effect of data treatment, was developed, resulting in improved correspondence (to within 2 %). The vDEC method yields fluxes which approximate the true (20 Hz) fluxes to within 3-7 % and it is this approach we recommend because it involves no additional empirical corrections. The only drawback of the vDEC method is the noisy nature of the cross-correlations, which poses problems with lag determination – practical approaches to overcome this limitation are discussed. PMID:24339727

  20. Neptune's Southern Hemisphere

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This photograph of Neptune's southern hemisphere was taken by the narrow-angle camera on NASA's Voyager 2 when the spacecraft was 4.2 million km (2.6 million miles) from the planet. The smallest features that can be seen are 38 km (24 miles) across. The almond-shaped structure at the left is a large cloud system that has been seen for several weeks. Internal details in the feature have become increasingly apparent as Voyager 2 has approached. Systems with similar shapes in Jupiter's atmosphere rotate about their centers, rolling in the local winds that increase toward the south. However, the wispy nature of the white central clouds in this Neptunian feature make confirmation of the system's rotation difficult. The Voyager Mission is conducted by JPL for NASA's Office of Space Science and Applications.

  1. A disjunctive kriging program for assessing point-support conditional distributions

    NASA Astrophysics Data System (ADS)

    Emery, Xavier

    2006-08-01

    In geostatistical applications, the local distributions of the values of a regionalized attribute at unsampled locations can be assessed by nonlinear methods such as indicator or multigaussian kriging. Disjunctive kriging can also be applied in the framework of bivariate isofactorial models, for which there exists a complete family of functions (factors) with no spatial cross-correlations. This work focuses on the point-support models with polynomial factors and gives practical tips for the modeling of the univariate and bivariate distributions and for the implementation of disjunctive kriging, mainly in what refers to the convergence of the expansions into factors, the post-processing of the estimated statistics and the use of ordinary kriging. The tools and concepts are complemented by a set of computer programs and applied to two case studies. The first one consists of topsoil samples measuring the lead concentration at a smelter site in Dallas, Texas. A gamma isofactorial model is fitted to these data and disjunctive kriging is used to map the local probabilities that the actual concentrations exceed a toxic threshold and to divide the smelter site into a safe and a polluted area. The second case study concerns the infestation of field crops by a caterpillar. A negative binomial model is used to characterize the number of bored stalk internodes and to assess the risk that this number exceeds given values.

  2. Aurora B prevents chromosome arm separation defects by promoting telomere dispersion and disjunction

    PubMed Central

    Reyes, Céline; Serrurier, Céline; Gauthier, Tiphaine

    2015-01-01

    The segregation of centromeres and telomeres at mitosis is coordinated at multiple levels to prevent the formation of aneuploid cells, a phenotype frequently observed in cancer. Mitotic instability arises from chromosome segregation defects, giving rise to chromatin bridges at anaphase. Most of these defects are corrected before anaphase onset by a mechanism involving Aurora B kinase, a key regulator of mitosis in a wide range of organisms. Here, we describe a new role for Aurora B in telomere dispersion and disjunction during fission yeast mitosis. Telomere dispersion initiates in metaphase, whereas disjunction takes place in anaphase. Dispersion is promoted by the dissociation of Swi6/HP1 and cohesin Rad21 from telomeres, whereas disjunction occurs at anaphase after the phosphorylation of condensin subunit Cnd2. Strikingly, we demonstrate that deletion of Ccq1, a telomeric shelterin component, rescued cell death after Aurora inhibition by promoting the loading of condensin on chromosome arms. Our findings reveal an essential role for telomeres in chromosome arm segregation. PMID:25778919

  3. Aurora B prevents chromosome arm separation defects by promoting telomere dispersion and disjunction.

    PubMed

    Reyes, Céline; Serrurier, Céline; Gauthier, Tiphaine; Gachet, Yannick; Tournier, Sylvie

    2015-03-16

    The segregation of centromeres and telomeres at mitosis is coordinated at multiple levels to prevent the formation of aneuploid cells, a phenotype frequently observed in cancer. Mitotic instability arises from chromosome segregation defects, giving rise to chromatin bridges at anaphase. Most of these defects are corrected before anaphase onset by a mechanism involving Aurora B kinase, a key regulator of mitosis in a wide range of organisms. Here, we describe a new role for Aurora B in telomere dispersion and disjunction during fission yeast mitosis. Telomere dispersion initiates in metaphase, whereas disjunction takes place in anaphase. Dispersion is promoted by the dissociation of Swi6/HP1 and cohesin Rad21 from telomeres, whereas disjunction occurs at anaphase after the phosphorylation of condensin subunit Cnd2. Strikingly, we demonstrate that deletion of Ccq1, a telomeric shelterin component, rescued cell death after Aurora inhibition by promoting the loading of condensin on chromosome arms. Our findings reveal an essential role for telomeres in chromosome arm segregation. PMID:25778919

  4. The emergence of reasoning by the disjunctive syllogism in early childhood.

    PubMed

    Mody, Shilpa; Carey, Susan

    2016-09-01

    Logical inference is often seen as an exclusively human and language-dependent ability, but several nonhuman animal species search in a manner that is consistent with a deductive inference, the disjunctive syllogism: when a reward is hidden in one of two cups, and one cup is shown to be empty, they will search for the reward in the other cup. In Experiment 1, we extended these results to toddlers, finding that 23-month-olds consistently approached the non-empty location. However, these results could reflect non-deductive approaches of simply avoiding the empty location, or of searching in any location that might contain the reward, rather than reasoning through the disjunctive syllogism to infer that the other location must contain the reward. Experiment 2 addressed these alternatives, finding evidence that 3- to 5-year-olds used the disjunctive syllogism, while 2.5-year-olds did not. This suggests that younger children may not easily deploy this logical inference, and that a non-deductive approach may be behind the successful performance of nonhuman animals and human infants. PMID:27239748

  5. A Left-Hemisphere Model for Right-Hemisphere Programmers.

    ERIC Educational Resources Information Center

    Krantz, Gordon C.

    The paper presents an action-and-decision (left-hemisphere) algorithm as a model for planning by holistic, intuitive (right-hemisphere) managers of service programs, including programs for exceptional children. Because the model is not based upon an established literature in the field of service to exceptional individuals, and because it appears…

  6. Right Hemisphere and Left Hemisphere: Pedagogical Implications for CSL Reading.

    ERIC Educational Resources Information Center

    Mickel, Stanley L.

    Students can be taught to read Chinese more efficiently and accurately by using the specific capabilities of the right and left hemispheres of the brain. The right hemisphere is the site of image and pattern recognition, and students can be taught to use those capacities to process individual characters efficiently by watching for the element of…

  7. Callisto Hemispherical Globes

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The images used for the base of this globe were chosen from the best image quality and moderate resolution coverage supplied by Galileo SSI and Voyager 1 and 2 (Batson, 1987; Becker and others, 1998; Becker and others, 1999; Becker and others, 2001). The digital map was produced using Integrated Software for Imagers and Spectrometers (ISIS) (Eliason, 1997; Gaddis and others, 1997; Torson and Becker, 1997). The individual images were radiometrically calibrated and photometrically normalized using a Lunar-Lambert function with empirically derived values (McEwen, 1991; Kirk and others, 2000). A linear correction based on the statistics of all overlapping areas was then applied to minimize image brightness variations. The image data were selected on the basis of overall image quality, reasonable original input resolution (from 20 km/pixel for gap fill to as much as 150 m/pixel), and availability of moderate emission/incidence angles for topography. Although consistency was achieved where possible, different filters were included for global image coverage as necessary: clear for Voyager 1 and 2; clear and green (559 nm) for Galileo SSI. Individual images were projected to a Sinusoidal Equal-Area projection at an image resolution of 1.0 kilometer/pixel, and a final global mosaic was constructed in this same projection. The final mosaic was enhanced using commercial software. The global mosaic was then reprojected so that the entire surface of Callisto is portrayed in a manner suitable for the production of a globe. A specialized program was used to create the 'flower petal' appearance of the images; the area of each petal from 0 to 75 degrees latitude is in the Transverse Mercator projection, and the area from 75 to 90 degrees latitude is in the Lambert Azimuthal Equal-Area projection. The projections for adjacent petals overlap by 2 degrees of longitude, so that some features are shown twice. The northern hemisphere is shown on the left, and the southern hemisphere is

  8. Europa Hemispherical Globes

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The images used for the base of this globe were chosen from coverage supplied by the Galileo solid-state imaging (SSI) camera and Voyager 1 and 2 spacecraft. The individual images were radiometrically calibrated and photometrically normalized using a Lunar-Lambert function with empirically derived values. A linear correction based on the statistics of all overlapping areas was then applied to minimize image brightness variations. The image data were selected on the basis of overall image quality, reasonable original input resolution (from 20 km/pixel for gap fill to as much as 200 m/pixel), and availability of moderate emission/incidence angles for topography. Although consistency was achieved where possible, different filters were included for global image coverage as necessary: clear/blue for Voyager 1 and 2, and clear, near-IR (757 nm), and green (559 nm) for Galileo SSI. Individual images were projected to a Sinusoidal Equal-Area projection at an image resolution of 500 m/pixel, and a final global mosaic was constructed in this same Sinusoidal projection.

    The global mosaic was then reprojected so that the entire surface of Europa is portrayed in a manner suitable for the production of a globe. A specialized program was used to create the 'flower petal' appearance of the images; the area of each petal from 0 to 75 degrees latitude is in the Transverse Mercator projection, and the area from 75 to 90 degrees latitude is in the Lambert Azimuthal Equal-Area projection. The projections for adjacent petals overlap by 2 degrees of longitude, so that some features are shown twice.

    Names shown on the globe are approved by the International Astronomical Union. The number, size, and placement of text were chosen for a 9-inch globe. A complete list of Europa nomenclature can be found at the Gazetteer of Planetary Nomenclature at http://planetarynames.wr.usgs.gov. The northern hemisphere is shown on the left, and the southern hemisphere is shown on the right.

  9. Callisto's Southern Hemisphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    These views of Callisto's southern hemisphere were taken by the Near Infrared Mapping Spectrometer just after closest approach in orbit G8 on May 6, 1997. These false color images show surface compositional differences, red = more ice, blue = less ice.

    The upper left view contains Buri, a crater with a diameter of about 60 km. In the infrared spectrum, Buri and the rays that extend from the crater have high abundance of water ice compared to the surrounding region. The center view, a large (200 km or 120 mile diameter) unnamed impact crater with a distinct ring or circle around it reveals a complex mix of ice and non-ice materials. This is possibly due to impact excavation of the ice-rich subsurface which suggests that the darker material is just a thin surface covering caused by impact debris or a lag deposit from which the ice has evaporated away. The infrared data shows spectral signatures for both sulfur and carbon as two potential materials which could play a part in the complicated make-up of Callisto's surface.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  10. Europa's Leading Hemisphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image of Europa's leading hemisphere was obtained by the solid state imaging (CCD) system on board NASA's Galileo spacecraft during its seventh orbit of Jupiter. In the upper left part of the image is Tyre, a multi-ringed structure that may have formed as a result of an ancient impact. Also visible are numerous lineaments that extend for over 1000 kilometers. The limb, or edge, of Europa in this image can be used by scientists to constrain the radius and shape of the satellite. North is to the top of the picture and the sun illuminates the surface from the right. The image, centered at -40 latitude and 180 longitude, covers an area approximately 2000 by 1300 kilometers. The finest details that can be discerned in this picture are about 6.6 kilometers across. The images were taken on April 3, 1997 at 17 hours, 42 minutes, 19 seconds Universal Time when the spacecraft was at a range of 31,8628 kilometers.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  11. Io's Kanehekili Hemisphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This color composite of Io, acquired by Galileo during its ninth orbit (C9) of Jupiter, shows the hemisphere of Io which is centered at longitude 52 degrees. The dark feature just to the lower right of the center of the disk is called Kanehekili. Named after an Hawaiian thunder god, Kanehekili contains two persistent high temperature hot spots and a 'new' active volcanic plume. NASA's Voyager spacecraft returned images of nine active plumes during its 1979 flyby of this dynamic satellite. To date, Galileo's plume monitoring observations have shown continued activity at four of those nine plume locations as well as new activity at six other locations.

    North is to the top of the picture which combines images acquired using violet, green, and near-infrared (756 micrometers) filters. The resolution is 21 kilometers per picture element. The images were taken on June 27, 1997 at a range of 1,033,000 kilometers by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  12. Detonation in TATB Hemispheres

    SciTech Connect

    Druce, B; Souers, P C; Chow, C; Roeske, F; Vitello, P; Hrousis, C

    2004-03-17

    Streak camera breakout and Fabry-Perot interferometer data have been taken on the outer surface of 1.80 g/cm{sup 3} TATB hemispherical boosters initiated by slapper detonators at three temperatures. The slapper causes breakout to occur at 54{sup o} at ambient temperatures and 42{sup o} at -54 C, where the axis of rotation is 0{sup o}. The Fabry velocities may be associated with pressures, and these decrease for large timing delays in breakout seen at the colder temperatures. At room temperature, the Fabry pressures appear constant at all angles. Both fresh and decade-old explosive are tested and no difference is seen. The problem has been modeled with reactive flow. Adjustment of the JWL for temperature makes little difference, but cooling to -54 C decreases the rate constant by 1/6th. The problem was run both at constant density and with density differences using two different codes. The ambient code results show that a density difference is probably there but it cannot be quantified.

  13. The Southern Hemisphere VLBI experiment

    SciTech Connect

    Preston, R.A.; Meier, D.L.; Louie, A.P.; Morabito, D.D.; Skjerve, L.; Slade, M.A.; Niell, A.E.; Wehrle, A.E.; Jauncey, D.L.; Tzioumis, A.K.; Haystack Observatory, Westford, MA; California Univ., Los Angeles; CSIRO, Div. of Radiophysics, Epping; Sydney Univ.; Manchester Victoria Univ., Jodrell Bank )

    1989-07-01

    Six radio telescopes were operated as the first Southern Hemisphere VLBI array in April and May 1982. Observations were made at 2.3 and 8.4 GHz. This array provided VLBI modeling and hybrid imaging of celestial radio sources in the Southern Hemisphere, high-accuracy VLBI geodesy between Southern Hemisphere sites, and subarcsecond radio astrometry of celestial sources south of declination -45 deg. The goals and implementation of the array are discussed, the methods of modeling and hybrid image production are explained, and the VLBI structure of the sources that were observed is summarized. 36 refs.

  14. Archimedes and the Magdeburg Hemispheres

    ERIC Educational Resources Information Center

    Hayn, Carl H.

    1975-01-01

    Weights suspended from a lever arm separate evacuated hemispheres allowing estimation of atmospheric pressure to within five percent of the barometric reading. An illustration and a reference to von Guericke's demonstration are provided. (GH)

  15. Brain Hemispheres and Thinking Styles.

    ERIC Educational Resources Information Center

    Gray, Esther Cappon

    1980-01-01

    The author reviews some research, particularly that of Roger Sperry, substantiating the existence of different thinking styles in the two brain hemispheres and the development of this differentiation in infancy and childhood. She draws some implications for elementary teaching. (SJL)

  16. Free form hemispherical shaped charge

    DOEpatents

    Haselman, L.C. Jr.

    1996-06-04

    A hemispherical shaped charge has been modified such that one side of the hemisphere is spherical and the other is aspherical allowing a wall thickness variation in the liner. A further modification is to use an elongated hemispherical shape. The liner has a thick wall at its pole and a thin wall at the equator with a continually decreasing wall thickness from the pole to the equator. The ratio of the wall thickness from the pole to the equator varies depending on liner material and HE shape. Hemispherical shaped charges have previously been limited to spherical shapes with no variations in wall thicknesses. By redesign of the basic liner thicknesses, the jet properties of coherence, stability, and mass distribution have been significantly improved. 8 figs.

  17. Free form hemispherical shaped charge

    DOEpatents

    Haselman, Jr., Leonard C.

    1996-01-01

    A hemispherical shaped charge has been modified such that one side of the hemisphere is spherical and the other is aspherical allowing a wall thickness variation in the liner. A further modification is to use an elongated hemispherical shape. The liner has a thick wall at its pole and a thin wall at the equator with a continually decreasing wall thickness from the pole to the equator. The ratio of the wall thickness from the pole to the equator varies depending on liner material and HE shape. Hemispherical shaped charges have previously been limited to spherical shapes with no variations in wall thicknesses. By redesign of the basic liner thicknesses, the jet properties of coherence, stability, and mass distribution have been significantly improved.

  18. Comparison of disjunctive kriging to generalized probability kriging in application to the estimation of simulated and real data

    SciTech Connect

    Carr, J.R. . Dept. of Geological Sciences); Mao, Nai-hsien )

    1992-01-01

    Disjunctive kriging has been compared previously to multigaussian kriging and indicator cokriging for estimation of cumulative distribution functions; it has yet to be compared extensively to probability kriging. Herein, disjunctive kriging and generalized probability kriging are applied to one real and one simulated data set and compared for estimation of the cumulative distribution functions. Generalized probability kriging is an extension, based on generalized cokriging theory, of simple probability kriging for the estimation of the indicator and uniform transforms at each cutoff, Z{sub k}. The disjunctive kriging and the generalized probability kriging give similar results for simulated data of normal distribution, but differ considerably for real data set with non-normal distribution.

  19. Genetic differentiation, niche divergence, and the origin and maintenance of the disjunct distribution in the Blossomcrown Anthocephala floriceps (Trochilidae).

    PubMed

    Lozano-Jaramillo, María; Rico-Guevara, Alejandro; Cadena, Carlos Daniel

    2014-01-01

    Studies of the origin and maintenance of disjunct distributions are of special interest in biogeography. Disjunct distributions can arise following extinction of intermediate populations of a formerly continuous range and later maintained by climatic specialization. We tested hypotheses about how the currently disjunct distribution of the Blossomcrown (Anthocephala floriceps), a hummingbird species endemic to Colombia, arose and how is it maintained. By combining molecular data and models of potential historical distributions we evaluated: (1) the timing of separation between the two populations of the species, (2) whether the disjunct distribution could have arisen as a result of fragmentation of a formerly widespread range due to climatic changes, and (3) if the disjunct distribution might be currently maintained by specialization of each population to different climatic conditions. We found that the two populations are reciprocally monophyletic for mitochondrial and nuclear loci, and that their divergence occurred ca. 1.4 million years before present (95% credibility interval 0.7-2.1 mybp). Distribution models based on environmental data show that climate has likely not been suitable for a fully continuous range over the past 130,000 years, but the potential distribution 6,000 ybp was considerably larger than at present. Tests of climatic divergence suggest that significant niche divergence between populations is a likely explanation for the maintenance of their disjunct ranges. However, based on climate the current range of A. floriceps could potentially be much larger than it currently is, suggesting other ecological or historical factors have influenced it. Our results showing that the distribution of A. floriceps has been discontinous for a long period of time and that populations exhibit different climatic niches have taxonomic and conservation implications. PMID:25251766

  20. Genetic Differentiation, Niche Divergence, and the Origin and Maintenance of the Disjunct Distribution in the Blossomcrown Anthocephala floriceps (Trochilidae)

    PubMed Central

    Lozano-Jaramillo, María; Rico-Guevara, Alejandro; Cadena, Carlos Daniel

    2014-01-01

    Studies of the origin and maintenance of disjunct distributions are of special interest in biogeography. Disjunct distributions can arise following extinction of intermediate populations of a formerly continuous range and later maintained by climatic specialization. We tested hypotheses about how the currently disjunct distribution of the Blossomcrown (Anthocephala floriceps), a hummingbird species endemic to Colombia, arose and how is it maintained. By combining molecular data and models of potential historical distributions we evaluated: (1) the timing of separation between the two populations of the species, (2) whether the disjunct distribution could have arisen as a result of fragmentation of a formerly widespread range due to climatic changes, and (3) if the disjunct distribution might be currently maintained by specialization of each population to different climatic conditions. We found that the two populations are reciprocally monophyletic for mitochondrial and nuclear loci, and that their divergence occurred ca. 1.4 million years before present (95% credibility interval 0.7–2.1 mybp). Distribution models based on environmental data show that climate has likely not been suitable for a fully continuous range over the past 130,000 years, but the potential distribution 6,000 ybp was considerably larger than at present. Tests of climatic divergence suggest that significant niche divergence between populations is a likely explanation for the maintenance of their disjunct ranges. However, based on climate the current range of A. floriceps could potentially be much larger than it currently is, suggesting other ecological or historical factors have influenced it. Our results showing that the distribution of A. floriceps has been discontinous for a long period of time and that populations exhibit different climatic niches have taxonomic and conservation implications. PMID:25251766

  1. Western Hemisphere Knowledge Partnerships

    NASA Astrophysics Data System (ADS)

    Malone, T. F.

    2001-05-01

    , and application of knowledge concerning the nature of -- and interaction among -- matter, living organisms, energy, information, and human behavior. This strategy calls for innovative partnerships among the physical, biological, health, and social sciences, engineering, and the humanities. New kinds of partnership must also be forged among academia, business and industry, governments, and nongovernmental organizations. Geophysicists can play an important role in these partnerships. A focus for these partnerships is to manage the individual economic productivity that drives both human development and global change. As world population approaches stability during the twenty-first century, individual economic productivity will be the critical link between the human and the natural systems on planet Earth. AGU is among a core group of individuals and institutions proposing Western Hemisphere Knowledge Partnerships (WHKP) to test the hypothesis that knowledge, broadly construed, is an important organizing principle in choosing a path into the future. The WHKP agenda includes: (1) life-long learning, (2) the health and resilience of natural ecosystems, (3) eco-efficiency in economic production and consumption, (4) extension of national income accounts, (5) environmentally benign sources of energy, (6) delivery of health care, (7) intellectual property rights, and (8) networks for action by local communities.Collaboratories and distance education technologies will be major tools. A panel of experts will explore this proposal.

  2. Zoogeography of South American Forest-Dwelling Bats: Disjunct Distributions or Sampling Deficiencies?

    PubMed

    da Rocha, Patrício Adriano; Ferrari, Stephen Francis; Feijó, Anderson; Gouveia, Sidney Feitosa

    2015-01-01

    Many forest-dwelling bats are purported to be widespread in South America, although records are scant from the vast diagonal belt of dry ecosystems that straddles the continent, implying possible sampling deficiencies. Here, we investigate this possibility in the case of four species of bat (Centronycteris maximiliani, Lampronycteris brachyotis, Peropteryx kappleri and Trinycteris nicefori), evaluating whether their disjunct present-day distributions reflect their true zoogeographic characteristics or the subsampling of intermediate zones. We use environmental niche modelling (ENM) in an ensemble approach, combining four different modeling techniques, and using niche descriptors based on climatic and remote sensing data, to estimate the potential distribution of the four species. The models indicate that all four species have disjunct distributions in the Amazon and Atlantic forest biomes. The one possible exception is P. kappleri, which the models indicated might potentially occur in humid forest enclaves in western Brazil and eastern Bolivia. The present-day distribution of the species may date back to the Plio-Pleistocene, when the forested biomes of South America were more extensive and connected. Further studies of different chiropteran lineages may provide additional insights into the historic processes of faunal interchange between the Amazon and Atlantic forest biomes. PMID:26186587

  3. Multisite phosphorylation of C-Nap1 releases it from Cep135 to trigger centrosome disjunction

    PubMed Central

    Hardy, Tara; Lee, Miseon; Hames, Rebecca S.; Prosser, Suzanna L.; Cheary, Donna-Marie; Samant, Mugdha D.; Schultz, Francisca; Baxter, Joanne E.; Rhee, Kunsoo; Fry, Andrew M.

    2014-01-01

    ABSTRACT During mitotic entry, centrosomes separate to establish the bipolar spindle. Delays in centrosome separation can perturb chromosome segregation and promote genetic instability. However, interphase centrosomes are physically tethered by a proteinaceous linker composed of C-Nap1 (also known as CEP250) and the filamentous protein rootletin. Linker disassembly occurs at the onset of mitosis in a process known as centrosome disjunction and is triggered by the Nek2-dependent phosphorylation of C-Nap1. However, the mechanistic consequences of C-Nap1 phosphorylation are unknown. Here, we demonstrate that Nek2 phosphorylates multiple residues within the C-terminal domain of C-Nap1 and, collectively, these phosphorylation events lead to loss of oligomerization and centrosome association. Mutations in non-phosphorylatable residues that make the domain more acidic are sufficient to release C-Nap1 from the centrosome, suggesting that it is an increase in overall negative charge that is required for this process. Importantly, phosphorylation of C-Nap1 also perturbs interaction with the core centriolar protein, Cep135, and interaction of endogenous C-Nap1 and Cep135 proteins is specifically lost in mitosis. We therefore propose that multisite phosphorylation of C-Nap1 by Nek2 perturbs both oligomerization and Cep135 interaction, and this precipitates centrosome disjunction at the onset of mitosis. PMID:24695856

  4. Prometaphase APCcdh1 activity prevents non-disjunction in mammalian oocytes

    PubMed Central

    Reis, Alexandra; Madgwick, Suzanne; Chang, Heng-Yu; Nabti, Ibtissem; Levasseur, Mark; Jones, Keith T

    2008-01-01

    Summary The first female meiotic division (MI) is uniquely prone to chromosome segregation errors through non-disjunction, resulting in trisomies and early pregnancy loss1. Here, we show a fundamental difference in the control of mammalian meiosis which may underlie such susceptibility. It involved a reversal in the well-established timing of activation of the Anaphase-Promoting Complex (APC)2, 3 by its co-activators cdc20 and cdh1. APCcdh1 was active first, during prometaphase I, and was needed in order to allow homologue congression, since loss of cdh1 speeded up MI, leading to premature chromosome segregation and a non-disjunction phenotype. APCcdh1 targeted cdc20 for degradation but not securin and cyclin B1. These were degraded later in MI through APCcdc20, making cdc20 re-synthesis essential for successful meiotic progression. The switch from APCcdh1 to APCcdc20 activity was controlled by increasing CDK1 and cdh1 loss. These findings demonstrate a fundamentally different mechanism of control for the first meiotic division in mammalian oocytes not observed in meioses of other species. PMID:17891138

  5. Prometaphase APCcdh1 activity prevents non-disjunction in mammalian oocytes.

    PubMed

    Reis, Alexandra; Madgwick, Suzanne; Chang, Heng-Yu; Nabti, Ibtissem; Levasseur, Mark; Jones, Keith T

    2007-10-01

    The first female meiotic division (meiosis I, MI) is uniquely prone to chromosome segregation errors through non-disjunction, resulting in trisomies and early pregnancy loss. Here, we show a fundamental difference in the control of mammalian meiosis that may underlie such susceptibility. It involves a reversal in the well-established timing of activation of the anaphase-promoting complex (APC) by its co-activators cdc20 and cdh1. APC(cdh1) was active first, during prometaphase I, and was needed in order to allow homologue congression, as loss of cdh1 speeded up MI, leading to premature chromosome segregation and a non-disjunction phenotype. APC(cdh1) targeted cdc20 for degradation, but did not target securin or cyclin B1. These were degraded later in MI through APC(cdc20), making cdc20 re-synthesis essential for successful meiotic progression. The switch from APC(cdh1) to APC(cdc20) activity was controlled by increasing CDK1 and cdh1 loss. These findings demonstrate a fundamentally different mechanism of control for the first meiotic division in mammalian oocytes that is not observed in meioses of other species. PMID:17891138

  6. Genetic divergence of peripherally disjunct populations of the gastropod Batillariella estuarina in the Houtman Abrolhos Islands, Western Australia.

    PubMed

    Pudovskis, M S; Johnson, M S; Black, R

    2001-11-01

    Geographically disjunct populations are unusual in marine species, but the Houtman Abrolhos Islands, Western Australia, provide opportunities to study highly disjunct peripheral isolates of several species. The intertidal snail Batillariella estuarina occurs in isolated tidal ponds in the Abrolhos Islands, where it is at its northern limit, disjunct from mainland populations by 600-900 km. The species is thus disjunct both geographically and among the peripherally isolated populations in the Abrolhos Islands. Comparisons of allozymes at 11 polymorphic loci were made among populations from 10 ponds in the Abrolhos Islands and six sites from relatively continuous tidal flats at Albany, 900 km away, the nearest major set of populations. Among all 16 populations, subdivision was high (FST = 0.455). Although there were subtle differences between the geographical regions, the large majority of divergence occurred among the isolated ponds in the Abrolhos (FST = 0.441), and divergence on the tidal flats at Albany was only moderate (FST = 0.085). Characteristic of peripheral isolates, the pond populations have less polymorphism and fewer alleles than the more connected populations at Albany. Combined with evidence of genetic divergence in the gastropods Bembicium vittatum and Austrocochlea constricta, which have very similar geographical distributions to that of B. estuarina, these results indicate the potential evolutionary significance of peripherally isolated marine populations in the unusual habitats of the Abrolhos Islands. PMID:11883876

  7. Acquiring the Scope of Disjunction and Negation in L2: A Bidirectional Study of Learners of Japanese and English

    ERIC Educational Resources Information Center

    Gruter, Theres; Lieberman, Moti; Gualmini, Andrea

    2010-01-01

    While L1 transfer and L2 learnability have been studied extensively in the domain of syntax and the syntax/semantics interface, purely semantic phenomena have received little attention in the L2 literature. This paper presents two experiments examining the relative scope assigned to disjunction and negation by English-speaking learners of Japanese…

  8. Blue Marble Western Hemisphere

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Drawing on data from multiple satellite missions (not all collected at the same time), a team of NASA scientists and graphic artists created layers of global data for everything from the land surface, to polar sea ice, to the light reflected by the chlorophyll in the billions of microscopic plants that grow in the ocean. They wrapped these layers around a globe, set it against a black background, and simulated the hazy edge of the Earth's atmosphere (the limb) that appears in astronaut photography of the Earth. The land surface layer is based on photo-like surface reflectance observations (reflected sunlight) measured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite in July 2004. The sea ice layer near the poles comes from Terra MODIS observations of daytime sea ice observed between August 28 and September 6, 2001. The ocean layer is a composite. In shallow water areas, the layer shows surface reflectances observed by Terra MODIS in July 2004. In the open ocean, the photo-like layer is overlaid with observations of the average ocean chlorophyll content for 2004. NASA's Aqua MODIS collected the chlorophyll data. The cloud layer shows a single-day snapshot of clouds observed by Terra MODIS across the planet on July 29, 2001. City lights on Earth's night side are visualized from data collected by the Defense Meteorological Satellite Program mission between 1994-1995. The topography layer is based on radar data collected by the Space Shuttle Endeavour during an 11-day mission in February of 2000. Topography over Antarctica comes from the Radarsat Antarctic Mapping Project, version 2.

  9. Blue Marble Eastern Hemisphere

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Drawing on data from multiple satellite missions (not all collected at the same time), a team of NASA scientists and graphic artists created layers of global data for everything from the land surface, to polar sea ice, to the light reflected by the chlorophyll in the billions of microscopic plants that grow in the ocean. They wrapped these layers around a globe, set it against a black background, and simulated the hazy edge of the Earth's atmosphere (the limb) that appears in astronaut photography of the Earth. The land surface layer is based on photo-like surface reflectance observations (reflected sunlight) measured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite in July 2004. The sea ice layer near the poles comes from Terra MODIS observations of daytime sea ice observed between August 28 and September 6, 2001. The ocean layer is a composite. In shallow water areas, the layer shows surface reflectances observed by Terra MODIS in July 2004. In the open ocean, the photo-like layer is overlaid with observations of the average ocean chlorophyll content for 2004. NASA's Aqua MODIS collected the chlorophyll data. The cloud layer shows a single-day snapshot of clouds observed by Terra MODIS across the planet on July 29, 2001. City lights on Earth's night side are visualized from data collected by the Defense Meteorological Satellite Program mission between 1994-1995. The topography layer is based on radar data collected by the Space Shuttle Endeavour during an 11-day mission in February of 2000. Topography over Antarctica comes from the Radarsat Antarctic Mapping Project, version 2.

  10. Seasonal hemispherical SWIR airglow imaging

    NASA Astrophysics Data System (ADS)

    Allen, Jeffrey; Dayton, David C.; Gonglewski, John D.; Myers, Michael M.; Nolasco, Rudolph

    2011-09-01

    Airglow luminescence in the SWIR region due to upper atmospheric recombination of solar excited molecules is a well accepted phenomenon. While the intensity appears broadly uniform over the whole sky hemisphere, we are interested in variations in four areas: 1) fine periodic features known as gravity waves, 2) broad patterns across the whole sky, 3) temporal variations in the hemispheric mean irradiance over the course of the night, and 4) long term seasonal variations in the mean irradiance. An experiment is described and results presented covering a full year of high resolution hemispheric SWIR irradiance images. An automated gimbal views 45 hemispheric positions, using 30 second durations, and repeats approximately every half hour through out the night. The gimbal holds co-mounted and bore-sighted visible and SWIR cameras. Measuring airglow with respect to spatial, temporal, and seasonal variations will facilitate understanding its behavior and possible benefits, such as night vision and predicting upper atmosphere turbulence. The measurements were performed in a tropical marine location on the island of Kauai Hi.

  11. A pox on the mind: Disjunction of attention and memory in the processing of physical disfigurement

    PubMed Central

    Ackerman, Joshua M.; Becker, D. Vaughn; Mortensen, Chad R.; Sasaki, Takao; Neuberg, Steven L.; Kenrick, Douglas T.

    2009-01-01

    The unfavorable treatment of people with physical disfigurements is well-documented, yet little is known about basic perceptual and cognitive responses to disfigurement. Here, we identify a specialized pattern of cognitive processing consistent with the hypothesis that disfigurements act as heuristic cues to contagious disease. Disfigurements are often invariant across time and difficult to conceal, and thus observers can detect the presence of such cues without necessarily remembering the particular individuals bearing these cues. Indeed, despite the fact that disfigured faces were especially likely to hold disease-sensitive perceivers’ attention (Study 1), disfigured individuals were often confused with one another and thus not well remembered later (Study 2), revealing a disjunction of the typical relationship between elevated attention and elevated memory. We discuss the implications of our results for stigmatization of people with and without physical abnormalities and suggest the possibility that cognitive mechanisms for processing social information may be functionally tuned to the variant nature of important cues. PMID:19578547

  12. Phenological Changes in the Southern Hemisphere

    PubMed Central

    Chambers, Lynda E.; Altwegg, Res; Barbraud, Christophe; Barnard, Phoebe; Beaumont, Linda J.; Crawford, Robert J. M.; Durant, Joel M.; Hughes, Lesley; Keatley, Marie R.; Low, Matt; Morellato, Patricia C.; Poloczanska, Elvira S.; Ruoppolo, Valeria; Vanstreels, Ralph E. T.; Woehler, Eric J.; Wolfaardt, Anton C.

    2013-01-01

    Current evidence of phenological responses to recent climate change is substantially biased towards northern hemisphere temperate regions. Given regional differences in climate change, shifts in phenology will not be uniform across the globe, and conclusions drawn from temperate systems in the northern hemisphere might not be applicable to other regions on the planet. We conduct the largest meta-analysis to date of phenological drivers and trends among southern hemisphere species, assessing 1208 long-term datasets from 89 studies on 347 species. Data were mostly from Australasia (Australia and New Zealand), South America and the Antarctic/subantarctic, and focused primarily on plants and birds. This meta-analysis shows an advance in the timing of spring events (with a strong Australian data bias), although substantial differences in trends were apparent among taxonomic groups and regions. When only statistically significant trends were considered, 82% of terrestrial datasets and 42% of marine datasets demonstrated an advance in phenology. Temperature was most frequently identified as the primary driver of phenological changes; however, in many studies it was the only climate variable considered. When precipitation was examined, it often played a key role but, in contrast with temperature, the direction of phenological shifts in response to precipitation variation was difficult to predict a priori. We discuss how phenological information can inform the adaptive capacity of species, their resilience, and constraints on autonomous adaptation. We also highlight serious weaknesses in past and current data collection and analyses at large regional scales (with very few studies in the tropics or from Africa) and dramatic taxonomic biases. If accurate predictions regarding the general effects of climate change on the biology of organisms are to be made, data collection policies focussing on targeting data-deficient regions and taxa need to be financially and logistically

  13. Bloom's syndrome and PICH helicases cooperate with topoisomerase IIα in centromere disjunction before anaphase.

    PubMed

    Rouzeau, Sébastien; Cordelières, Fabrice P; Buhagiar-Labarchède, Géraldine; Hurbain, Ilse; Onclercq-Delic, Rosine; Gemble, Simon; Magnaghi-Jaulin, Laura; Jaulin, Christian; Amor-Guéret, Mounira

    2012-01-01

    Centromeres are specialized chromosome domains that control chromosome segregation during mitosis, but little is known about the mechanisms underlying the maintenance of their integrity. Centromeric ultrafine anaphase bridges are physiological DNA structures thought to contain unresolved DNA catenations between the centromeres separating during anaphase. BLM and PICH helicases colocalize at these ultrafine anaphase bridges and promote their resolution. As PICH is detectable at centromeres from prometaphase onwards, we hypothesized that BLM might also be located at centromeres and that the two proteins might cooperate to resolve DNA catenations before the onset of anaphase. Using immunofluorescence analyses, we demonstrated the recruitment of BLM to centromeres from G2 phase to mitosis. With a combination of fluorescence in situ hybridization, electron microscopy, RNA interference, chromosome spreads and chromatin immunoprecipitation, we showed that both BLM-deficient and PICH-deficient prometaphase cells displayed changes in centromere structure. These cells also had a higher frequency of centromeric non disjunction in the absence of cohesin, suggesting the persistence of catenations. Both proteins were required for the correct recruitment to the centromere of active topoisomerase IIα, an enzyme specialized in the catenation/decatenation process. These observations reveal the existence of a functional relationship between BLM, PICH and topoisomerase IIα in the centromere decatenation process. They indicate that the higher frequency of centromeric ultrafine anaphase bridges in BLM-deficient cells and in cells treated with topoisomerase IIα inhibitors is probably due not only to unresolved physiological ultrafine anaphase bridges, but also to newly formed ultrafine anaphase bridges. We suggest that BLM and PICH cooperate in rendering centromeric catenates accessible to topoisomerase IIα, thereby facilitating correct centromere disjunction and preventing the

  14. Comparison of two techniques for applying disjunctive kriging: the Gaussian anamorphosis model versus the direct statistical inference of the bivariate distributions

    SciTech Connect

    Carr, J.R.; Deng, E.D.

    1987-01-01

    Indicator atcokriging is an alternative to disjunctive kriging for estimation of spatial distributions. One way to determine which of these techniques is more accurate for estimation of spatial distributions is to apply each to a particular type of data. A procedure is developed for evaluation of disjunctive kriging and indicator atcokriging for such an application. Application of this procedure to earthquake ground motion data found disjunctive kriging to be at least as accurate as indicator atcokriging for estimation of spatial distributions for peak horizontal acceleration. Indicator atcokriging was superior for all other types of earthquake ground motion data.

  15. Hemispheric ultra-wideband antenna.

    SciTech Connect

    Brocato, Robert Wesley

    2006-04-01

    This report begins with a review of reduced size ultra-wideband (UWB) antennas and the peculiar problems that arise when building a UWB antenna. It then gives a description of a new type of UWB antenna that resolves these problems. This antenna, dubbed the hemispheric conical antenna, is similar to a conventional conical antenna in that it uses the same inverted conical conductor over a ground plane, but it also uses a hemispheric dielectric fill in between the conductive cone and the ground plane. The dielectric material creates a fundamentally new antenna which is reduced in size and much more rugged than a standard UWB conical antenna. The creation of finite-difference time domain (FDTD) software tools in spherical coordinates, as described in SAND2004-6577, enabled this technological advance.

  16. Focal hemisphere and visuoperceptual categorization.

    PubMed Central

    Bisiach, E; Capitani, E; Spinnler, H

    1975-01-01

    Visuoperceptual categorization was investigated in patients with unilateral brain damage by a task in which meaningless shapes had to be classified with reference to a number of prototype patterns. Right brain-damaged subjects with visual field defect turned out to have a narrower categorization span. As this outcome seems to be scarcely consonant with a lower level disorder of visual processing, a major competence of the right hemisphere is suggested for visuoperceptual categorization. PMID:1206421

  17. Classifying Southern Hemisphere extratropical cyclones

    NASA Astrophysics Data System (ADS)

    Catto, Jennifer

    2015-04-01

    There is a wide variety of flavours of extratropical cyclones in the Southern Hemisphere, with differing structures and lifecycles. Previous studies have classified these manually using upper level flow features or satellite data. In order to be able to evaluate climate models and understand how extratropical cyclones might change in the future, we need to be able to use an automated method to classify cyclones. Extratropical cyclones have been identified in the Southern Hemisphere from the ERA-Interim reanalysis dataset with a commonly used identification and tracking algorithm that employs 850hPa relative vorticity. A clustering method applied to large-scale fields from ERA-Interim at the time of cyclone genesis (when the cyclone is first identified), has been used to objectively classify these cyclones in the Southern Hemisphere. This simple method is able to separate the cyclones into classes with quite different development mechanisms and lifecycle characteristics. Some of the classes seem to coincide with previous manual classifications on shorter timescales, showing their utility for climate model evaluation and climate change studies.

  18. Awake right hemisphere brain surgery.

    PubMed

    Hulou, M Maher; Cote, David J; Olubiyi, Olutayo I; Smith, Timothy R; Chiocca, E Antonio; Johnson, Mark D

    2015-12-01

    We report the indications and outcomes of awake right hemispheric brain surgery, as well as a rare patient with crossed aphasia. Awake craniotomies are often performed to protect eloquent cortex. We reviewed the medical records for 35 of 96 patients, in detail, who had awake right hemisphere brain operations. Intraoperative cortical mapping of motor and/or language function was performed in 29 of the 35 patients. A preoperative speech impairment and left hand dominance were the main indicators for awake right-sided craniotomies in patients with right hemisphere lesions. Four patients with lesion proximity to eloquent areas underwent awake craniotomies without cortical mapping. In addition, one patient had a broncho-pulmonary fistula, and another had a recent major cardiac procedure that precluded awake surgery. An eloquent cortex representation was identified in 14 patients (48.3%). Postoperatively, seven of 17 patients (41.1%) who presented with weakness, experienced improvements in their motor functions, 11 of 16 (68.7%) with seizures became seizure-free, and seven of nine (77.7%) with moderate to severe headaches and one of two with a visual field deficit improved significantly. There were also improvements in speech and language functions in all patients who presented with speech difficulties. A right sided awake craniotomy is an excellent option for left handed patients, or those with right sided cortical lesions that result in preoperative speech impairments. When combined with intraoperative cortical mapping, both speech and motor function can be well preserved. PMID:26279501

  19. Hemispheric Assymeries in Auroral Precipitation

    NASA Astrophysics Data System (ADS)

    Mende, S. B.

    2014-12-01

    It is widely accepted that the space weather related electrodynamic forcing of the geospace environment acts through the high geomagnetic latitude regions. At high latitudes inter-hemispheric asymmetries are largely due to the differences in solar illumination, the direction of the solar wind and interplanetary magnetic field components and to a lesser extent, due to differences between the two hemispheric internal fields. So far most research regarding interhemispheric differences concentrated on learning about the basic magnetosphere-ionosphere coupling mechanisms. It has been well established that sunlit conditions affect the energy flux of auroral precipitation resulting from the reduction in the mean energy of the auroral electrons in the sunlit summer hemisphere. This can be explained by the partial shorting out of the particle accelerating fields by the sunlight induced conductivity. It has also been found that sunlit conditions reduce the particle fluxes and therefore the associated field aligned currents. Unless the precipitation-induced conductivities overwhelm the sunlit component of conductivity, this would imply that the magnetospheric current generator responds to the ionospheric load in a highly non-linear manner. Interhemispheric currents may also play an important role that has not been fully explored. Interhemispheric asymmetries in substorm morphology have been explored critically because conjugacy implies that substorms have a common source at equatorial latitudes. In some cases the lack of conjugacy of substorms could be explained by considering the magnitude and direction of the IMF.

  20. Right Hemisphere Dominance in Visual Statistical Learning

    ERIC Educational Resources Information Center

    Roser, Matthew E.; Fiser, Jozsef; Aslin, Richard N.; Gazzaniga, Michael S.

    2011-01-01

    Several studies report a right hemisphere advantage for visuospatial integration and a left hemisphere advantage for inferring conceptual knowledge from patterns of covariation. The present study examined hemispheric asymmetry in the implicit learning of new visual feature combinations. A split-brain patient and normal control participants viewed…

  1. Brain Hemispheric Functions and the Native American.

    ERIC Educational Resources Information Center

    Ross, Allen Chuck

    1982-01-01

    Uses brain research conducted by Dr. Roger Sperry to show that traditional Native Americans are more dominant in right hemisphere thinking, setting them apart from a modern left hemisphere-oriented society (especially emphasized in schools). Describes some characteristics of Native American thinking that illustrate a right hemisphere orientation…

  2. Hemispheric Laterality in Music and Math

    ERIC Educational Resources Information Center

    Szirony, Gary Michael; Burgin, John S.; Pearson, L. Carolyn

    2008-01-01

    Hemispheric laterality may be a useful concept in teaching, learning, training, and in understanding more about human development. To address this issue, a measure of hemispheric laterality was compared to musical and mathematical ability. The Human Information Processing Survey (HIPS) instrument, designed to measure hemispheric laterality, was…

  3. Mitral annular disjunction in myxomatous mitral valve disease: a relevant abnormality recognizable by transthoracic echocardiography

    PubMed Central

    2010-01-01

    Background Mitral annular disjunction (MAD) consists of an altered spatial relation between the left atrial wall, the attachment of the mitral leaflets, and the top of the left ventricular (LV) free wall, manifested as a wide separation between the atrial wall-mitral valve junction and the top of the LV free wall. Originally described in association with myxomatous mitral valve disease, this abnormality was recently revisited by a surgical group that pointed its relevance for mitral valve reparability. The aims of this study were to investigate the echocardiographic prevalence of mitral annular disjunction in patients with myxomatous mitral valve disease, and to characterize the clinical profile and echocardiographic features of these patients. Methods We evaluated 38 patients with myxomatous mitral valve disease (mean age 57 ± 15 years; 18 females) and used standard transthoracic echocardiography for measuring the MAD. Mitral annular function, assessed by end-diastolic and end-systolic annular diameters, was compared between patients with and without MAD. We compared the incidence of arrhythmias in a subset of 21 patients studied with 24-hour Holter monitoring. Results MAD was present in 21 (55%) patients (mean length: 7.4 ± 8.7 mm), and was more common in women (61% vs 38% in men; p = 0.047). MAD patients more frequently presented chest pain (43% vs 12% in the absence of MAD; p = 0.07). Mitral annular function was significantly impaired in patients with MAD in whom the mitral annular diameter was paradoxically larger in systole than in diastole: the diastolic-to-systolic mitral annular diameter difference was -4,6 ± 4,7 mm in these patients vs 3,4 ± 1,1 mm in those without MAD (p < 0.001). The severity of MAD significantly correlated with the occurrence of non-sustained ventricular tachycardia (NSVT) on Holter monitoring: MAD›8.5 mm was a strong predictor for (NSVT), (area under ROC curve = 0.74 (95% CI, 0.5-0.9); sensitivity 67%, specificity 83%). There

  4. Electric analysis of a conducting hemisphere

    NASA Astrophysics Data System (ADS)

    Yang, Mimi X.; Yang, Fuqian

    2016-05-01

    Using Legendre polynomials, the boundary value problem of a charged, conducting hemisphere in an infinite space was reduced to the solution of an infinite system of linear, algebraic equations. Analytical solutions of electric charge and electric stress on the surface of the hemisphere were obtained. The numerical analysis revealed non-uniform distributions of the electric charge and electric stress over the surface of the hemisphere with local singularities at the edge of the hemisphere. Both the electric charge and electric stress distributions were expressed in terms of the power function with respect to the distance to the nearest hemisphere edge. The power index for the flat surface is larger than that corresponding to the spherical surface. Numerical result of the capacitance of the conducting hemisphere is the same as the result reported in the literature. There is no net force acting on the hemisphere.

  5. PICH promotes sister chromatid disjunction and co-operates with topoisomerase II in mitosis.

    PubMed

    Nielsen, Christian F; Huttner, Diana; Bizard, Anna H; Hirano, Seiki; Li, Tian-Neng; Palmai-Pallag, Timea; Bjerregaard, Victoria A; Liu, Ying; Nigg, Erich A; Wang, Lily Hui-Ching; Hickson, Ian D

    2015-01-01

    PICH is a SNF2 family DNA translocase that binds to ultra-fine DNA bridges (UFBs) in mitosis. Numerous roles for PICH have been proposed from protein depletion experiments, but a consensus has failed to emerge. Here, we report that deletion of PICH in avian cells causes chromosome structural abnormalities, and hypersensitivity to an inhibitor of Topoisomerase II (Topo II), ICRF-193. ICRF-193-treated PICH(-/-) cells undergo sister chromatid non-disjunction in anaphase, and frequently abort cytokinesis. PICH co-localizes with Topo IIα on UFBs and at the ribosomal DNA locus, and the timely resolution of both structures depends on the ATPase activity of PICH. Purified PICH protein strongly stimulates the catalytic activity of Topo II in vitro. Consistent with this, a human PICH(-/-) cell line exhibits chromosome instability and chromosome condensation and decatenation defects similar to those of ICRF-193-treated cells. We propose that PICH and Topo II cooperate to prevent chromosome missegregation events in mitosis. PMID:26643143

  6. PICH promotes sister chromatid disjunction and co-operates with topoisomerase II in mitosis

    PubMed Central

    Nielsen, Christian F.; Huttner, Diana; Bizard, Anna H.; Hirano, Seiki; Li, Tian-Neng; Palmai-Pallag, Timea; Bjerregaard, Victoria A.; Liu, Ying; Nigg, Erich A.; Wang, Lily Hui-Ching; Hickson, Ian D.

    2015-01-01

    PICH is a SNF2 family DNA translocase that binds to ultra-fine DNA bridges (UFBs) in mitosis. Numerous roles for PICH have been proposed from protein depletion experiments, but a consensus has failed to emerge. Here, we report that deletion of PICH in avian cells causes chromosome structural abnormalities, and hypersensitivity to an inhibitor of Topoisomerase II (Topo II), ICRF-193. ICRF-193-treated PICH−/− cells undergo sister chromatid non-disjunction in anaphase, and frequently abort cytokinesis. PICH co-localizes with Topo IIα on UFBs and at the ribosomal DNA locus, and the timely resolution of both structures depends on the ATPase activity of PICH. Purified PICH protein strongly stimulates the catalytic activity of Topo II in vitro. Consistent with this, a human PICH−/− cell line exhibits chromosome instability and chromosome condensation and decatenation defects similar to those of ICRF-193-treated cells. We propose that PICH and Topo II cooperate to prevent chromosome missegregation events in mitosis. PMID:26643143

  7. New Insights into the Genetic Regulation of Homologue Disjunction in Mammalian Oocytes

    PubMed Central

    Homer, H.

    2011-01-01

    Mammalian oocytes execute a unique meiotic programme involving 2 arrest stages and an unusually protracted preamble to chromosome segregation during the first meiotic division (meiosis I). How mammalian oocytes successfully navigate their exceptional meiotic journey has long been a question of immense interest. Understanding the minutiae of female mammalian meiosis I is not merely of academic interest as 80–90% of human aneuploidy is the consequence of errors arising at this particular stage of oocyte maturation, a stage with a peculiar vulnerability to aging. Recent evidence indicates that oocytes employ many of the same cast of proteins during meiosis I as somatic cells do during mitosis, often to execute similar tasks, but intriguingly, occasionally delegate them to unexpected and unprecedented roles. This is epitomised by the master cell-cycle regulon, the anaphase-promoting complex or cyclosome (APC/C), acting in concert with a critical APC/C-targeted surveillance mechanism, the spindle assembly checkpoint (SAC). Together, the APC/C and the SAC are among the most influential entities overseeing the fidelity of cell-cycle progression and the precision of chromosome segregation. Here I review the current status of pivotal elements underpinning homologue disjunction in mammalian oocytes including spindle assembly, critical biochemical anaphase-initiating events, APC/C activity and SAC signalling along with contemporary findings relevant to progressive oocyte SAC dysfunction as a model for age-related human aneuploidy. PMID:21335952

  8. Public engagement in climate change - Disjunctions, tensions and blind spots in the UK

    NASA Astrophysics Data System (ADS)

    Höppner, C.

    2009-11-01

    There is much talk about engaging the public in climate change mitigation and adaptation in the UK and elsewhere. Governments rush to demand greater engagement of the public in tackling climate change and delivering sustainable futures. The importance that public engagement has gained as part of the UK climate agenda begs the questions of what is actually behind this call and what are the implications. This paper analyses the rationale for public engagement as enshrined in major policy documents. This rationale is clearly instrumental in that citizens are expected to engage by adopting the 'right attitude', by performing prescribed behaviours, and by consenting to proposed measures. Using recent cases of climate change mitigation and adaptation practice the paper discusses the implications of such an approach to public engagement. The paper concludes that until the manifold disjunctions between climate related policy agendas and their rationales for engagement are explicitly addressed citizen engagement will be serving incumbent interests rather than contributing to socially sustainable and democratic decision-making

  9. Dis1: A Yeast Gene Required for Proper Meiotic Chromosome Disjunction

    PubMed Central

    Rockmill, B.; Fogel, S.

    1988-01-01

    Mutants at a newly identified locus, DIS1 (disjunction), were detected by screening for mutants that generate aneuploid spores (chromosome VIII disomes) at an increased frequency. Strains carrying the partially dominant alleles, DIS1-1 or DIS1-2, generate disomes at rates up to 100 times the background level. Mitotic nondisjunction is also increased 10- to 50-fold over background. Half-tetrad analysis of disomes for a marked interval on chromosome VIII yields wild-type map distances, indicating that a general recombination deficiency is not the cause of nondisjuction. Meiotic nondisjunction in DIS1 mutants is not chromosome specific; 5% of the spores disomic for chromosome VIII are also disomic for chromosome III. Although only one disomic spore is found per exceptional ascus most of the disomes appear to be generated in the first meiotic division because recovered chromosome VIII disomes contain mostly nonsister chromosomes. We propose that disome generation in the DIS1 mutants results from precocious separation of sister centromeres. PMID:3294101

  10. Relative time scales reveal multiple origins of parallel disjunct distributions of African caecilian amphibians.

    PubMed

    Loader, Simon P; Pisani, Davide; Cotton, James A; Gower, David J; Day, Julia J; Wilkinson, Mark

    2007-10-22

    Parallel patterns of distribution in different lineages suggest a common cause. Explanations in terms of a single biogeographic event often imply contemporaneous diversifications. Phylogenies with absolute time scales provide the most obvious means of testing temporal components of biogeographic hypotheses but, in their absence, the sequence of diversification events and whether any could have been contemporaneous can be tested with relative date estimates. Tests using relative time scales have been largely overlooked, but because they do not require the calibration upon which absolute time scales depend, they make a large amount of existing molecular data of use to historical biogeography and may also be helpful when calibration is possible but uncertain. We illustrate the use of relative dating by testing the hypothesis that parallel, disjunct east/west distributions in three independent lineages of African caecilians have a common cause. We demonstrate that at least two biogeographic events are implied by molecular data. Relative dating analysis reveals the potential complexity of causes of parallel distributions and cautions against inferring common cause from common spatial patterns without considering the temporal dimension. PMID:17609171

  11. Electroformation of uranium hemispherical shells

    SciTech Connect

    Marshall, S.L.; Redey, L.; Vandegrift, G.F.; Vissers, D.R.

    1989-11-01

    This effort was directed at developing an electrochemical process for forming uniform and dendrite-free deposits of uranium from molten salts. This process is to be used for the electroformation of free-standing hemispherical shells of uranium for nuclear applications. Electrodeposition of uranium onto a substrate was accomplished with a fused chloride mixture containing 42 wt% UCl{sub 3} and a fused chloride-fluoride mixture containing 4 wt % UF{sub 4}. Under pulsed potential control at 504{degree}C, the chloride-fluoride mixture yielded the widest range of plating conditions for which dendrites could be avoided. Bipolar current pulse plating with both electrolytes gave good results, and successful application of this technique to a large tubular cathode has been demonstrated. 24 refs., 10 figs.

  12. Hemispheric Asymmetries: The Comparative View

    PubMed Central

    Ocklenburg, Sebastian; Güntürkün, Onur

    2012-01-01

    Hemispheric asymmetries play an important role in almost all cognitive functions. For more than a century, they were considered to be uniquely human but now an increasing number of findings in all vertebrate classes make it likely that we inherited our asymmetries from common ancestors. Thus, studying animal models could provide unique insights into the mechanisms of lateralization. We outline three such avenues of research by providing an overview of experiments on left–right differences in the connectivity of sensory systems, the embryonic determinants of brain asymmetries, and the genetics of lateralization. All these lines of studies could provide a wealth of insights into our own asymmetries that should and will be exploited by future analyses. PMID:22303295

  13. Microsatellite-based genetic diversity patterns in disjunct populations of a rare orchid.

    PubMed

    Pandey, Madhav; Richards, Matt; Sharma, Jyotsna

    2015-12-01

    We investigated the patterns of genetic diversity and structure in seven disjunct populations of a rare North American orchid, Cypripedium kentuckiense by including populations that represented the periphery and the center of the its range. Eight nuclear and two chloroplast microsatellites were used. Genetic diversity was low across the sampled populations of C. kentuckiense based on both nuclear (average An = 4.0, Ho = 0.436, He = 0.448) and cpDNA microsatellites (average An = 1.57, Nh = 1.57 and H = 0.133). The number of private alleles ranged from one to four per population with a total of 17 private alleles detected at five nuclear microsatellites. One private allele at one cpDNA microsatellite was also observed. Although the absolute values for nuclear microsatellite based population differentiation were low (Fst = 0.075; ϕPT = 0.24), they were statistically significant. Pairwise Fst values ranged from 0.038 to 0.123 and each comparison was significant. We also detected isolation by distance with nDNA microsatellites based on the Mantel test (r(2) = 0.209, P = 0.05). STRUCTURE analysis and the neighbor joining trees grouped the populations similarly whereby the geographically proximal populations were genetically similar. Our data indicate that the species is genetically depauperate but the diversity is distributed more or less equally across its range. Population differentiation and isolation by distance were detectable, which indicates that genetic isolation is beginning to manifest itself across the range in this rare species. PMID:26481007

  14. Homotopic Language Reorganization in the Right Hemisphere after Early Left Hemisphere Injury

    ERIC Educational Resources Information Center

    Tivarus, Madalina E.; Starling, Sarah J.; Newport, Elissa L.; Langfitt, John T.

    2012-01-01

    To determine the areas involved in reorganization of language to the right hemisphere after early left hemisphere injury, we compared fMRI activation patterns during four production and comprehension tasks in post-surgical epilepsy patients with either left (LH) or right hemisphere (RH) speech dominance (determined by Wada testing) and healthy…

  15. An overview of Fukushima radionuclides measured in the northern hemisphere.

    PubMed

    Thakur, P; Ballard, S; Nelson, R

    2013-08-01

    The Great East Japan Earthquake and tsunami on March 11, 2011 resulted in the tragic accident at the Fukushima Nuclear Power Plant (NPP) and subsequently uncontrolled release of radioactive contaminants into the atmosphere. This review article attempts to compile and interpret data collected by various national and international monitoring networks in response to the Fukushima releases across the northern hemisphere. The majority of the releases occurred during the period March 12-22 with a maximum release phase from March 14-17, 2011. The radioactivity released was dominated by volatile fission products including isotopes of the noble gases (xenon and krypton), iodine, cesium, and tellurium. The radioactive gases and particles released in the accident were dispersed over the middle latitudes of the entire northern hemisphere and for the first time also measured in the southern Hemisphere. Isotopes of iodine and cesium were detected in air, water, milk and food samples collected across the entire northern hemisphere. Elevated levels of fission products were detected from March to May 2011 at many locations over the northern hemisphere. This article focuses on the most prevalent cesium and iodine isotopes, but other secondary isotopes are also discussed. Spatial and temporal patterns and differences are contrasted. The activity ratios of (131)I/(137)Cs and (134)Cs/(137)Cs measured at several locations are evaluated to gain an insight into the fuel burn-up, the inventory of radionuclides in the reactor and the isotopic signature of the accident. It is important to note that all of the radiation levels detected outside of Japan have been very low and are well below any level of public and environmental hazard. PMID:23707866

  16. Fantasy and the Brain's Right Hemisphere.

    ERIC Educational Resources Information Center

    Shuman, R. Baird

    While the left hemisphere of the brain is responsible for logical and verbal activity, the right brain is the center of much of human feeling and emotion. Its vision is holistic rather than segmented or compartmentalized. Although schools today are geared almost exclusively to training the brain's left hemisphere, fantasy literature can provide…

  17. The Cost of Action Miscues: Hemispheric Asymmetries

    ERIC Educational Resources Information Center

    Shenal, Brian V.; Hinze, Stephan; Heilman, Kenneth M.

    2012-01-01

    Adaptive behaviors require preparation and when necessary inhibition or alteration of actions. The right hemisphere has been posited to be dominant for preparatory motor activation. This experiment was designed to learn if there are hemispheric asymmetries in the control of altered plans of actions. Cues, both valid and invalid, which indicate the…

  18. UV Observations of Hemispheric Asymmetry

    NASA Astrophysics Data System (ADS)

    Schaefer, R. K.; Paxton, L. J.; Wolven, B. C.; Zhang, Y.; Romeo, G.

    2015-12-01

    Asymmetry in the auroral patterns can be an important diagnostic for understanding the dynamics of solar wind interaction with the magnetosphere-ionosphere-thermosphere system (e.g., Newel and Meng, 1998; Fillingrim et al., 2005). Molecular nitrogen emission in the UV Lyman-Birge-Hopfield bands can be used to determine energy flux and electron mean energy (Sotirelis, et al, 2013) and thereby Hall and Pederson integrated conductances (Gjerloev, et al., 2014). UV imagery provided by the 4 SSUSI instruments on the Defense Meteorological Satellite Program (DMSP) F16-F19 spacecraft provide two dimensional maps of this emission at different local times. Often there are near simultaneous observations of both poles by some combination of the satellites. (see figure 1) The SSUSI auroral data products are well suited to this study, as they have the following features.: - dayglow has been subtracted on dayside aurora - electron energy flux and mean energy are pre-calculated - individual arcs have been identified through image processing. In order to intercompare data from multiple satellites, we must first ensure that the instrument calibrations are consistent. In this work we show that the instruments are consistently calibrated, and that results generated from the SSUSI data products can be trusted. Several examples of storm time asymmetries captured by the SSUSI instruments will be discussed. Fillingim, M. O., G. K. Parks, H. U. Frey, T. J. Immel, and S. B. Mende (2005), Hemispheric asymmetry of the afternoon electron aurora, Geophys. Res. Lett., 32, L03113, doi:10.1029/2004GL021635. Gjerloev, J., Schaefer, R., Paxton, L, and Zhang, Y. (2014), A comprehensive empirical model of the ionospheric conductivity derived from SSUSI/GUVI, SuperMAG and SuperDARN data, SM51G-4339, Fall 2014 AGU meeting, San Francisco. Newell, P. T., and C.-I. Meng (1988), Hemispherical asymmetry in cusp precipitation near solstices, J. Geophys. Res., 93(A4), 2643-2648, doi:10.1029/JA093iA04p02643

  19. Reciprocal organization of the cerebral hemispheres

    PubMed Central

    McGilchrist, Iain

    2010-01-01

    The cerebral hemispheres are anatomically and neurophysiologically asymmetrical. The evolutionary basis for these differences remains uncertain. There are, however, highly consistent differences between the hemispheres, evident in reptiles, birds, and mammals, as well as in humans, in the nature of the attention each applies to the environment. This permits the simultaneous application of precisely focused, but narrow, attention, needed for grasping food or prey, with broad, open, and uncommitted attention, needed to watch out for predators and to interpret the intentions of conspecifics. These different modes of attention can account for a very wide range of repeated observations relating to hemisphere specialization, and suggest that hemisphere differences lie not in discrete functional domains as such, but distinct modes of functioning within any one domain. These modes of attention are mutually incompatible, and their application depends on inhibitory transmission in the corpus callosum. There is also an asymmetry of interaction between the hemispheres at the phenomenological level. PMID:21319495

  20. Temporal variation of hemispheric solar rotation

    NASA Astrophysics Data System (ADS)

    Xie, Jing-Lan; Shi, Xiang-Jun; Xu, Jing-Chen

    2012-02-01

    The daily sunspot numbers of the whole disk as well as the northern and southern hemispheres from 1945 January 1 to 2010 December 31 are used to investigate the temporal variation of rotational cycle length through the continuous wavelet transformation analysis method. Auto-correlation function analysis of daily hemispheric sunspot numbers shows that the southern hemisphere rotates faster than the northern hemisphere. The results obtained from the wavelet transformation analysis are that no direct relationship exists between the variation trend of the rotational cycle length and the solar activity in the two hemispheres and that the rotational cycle length of both hemispheres has no significant period appearing at 11yr, but has a significant period of about 7.6 yr. Analysis concerning the solar cycle dependence of the rotational cycle length shows that acceleration seems to appear before the minimum time of solar activity in the whole disk and the northern hemisphere, respectively. Furthermore, the cross-correlation study indicates that the rotational cycle length of the two hemispheres has different phases, and that the rotational cycle length of the whole disk as well as the northern and southern hemispheres, also has phase shifts with corresponding solar activity. In addition, the temporal variation of the north-south (N-S) asymmetry of the rotational cycle length is also studied. This displays the same variation trend as the N-S asymmetry of solar activity in a solar cycle, as well as in the considered time interval, and has two significant periods of 7.7 and 17.5 yr. Moreover, the rotational cycle length and the N-S asymmetry of solar activity are highly correlated. It is inferred that the northern hemisphere should rotate faster at the beginning of solar cycle 24.

  1. Ontogenesis of hemispheric specialization: apraxia associated with congenital left hemisphere lesions.

    PubMed

    Nass, R

    1983-12-01

    In adults apraxia is more common after left-hemisphere damage. The engram for control of skilled motor movements has therefore been considered a specialized function of the left hemisphere. The ontogenesis of motor control was studied in a group of prepubertal children with congenital unilateral hemispheric lesions. Left-hemisphere lesions caused greater impairment of rapid independent finger movements, suggesting that specialization for motor control is innately programmed in the left hemisphere. No subject evidenced apraxia to verbal command, but adult-like performance is not yet expected at the age the group was tested, and effects of side of lesion could appear later. PMID:6664762

  2. The Asgard Hemisphere of Callisto

    NASA Technical Reports Server (NTRS)

    1997-01-01

    False color view of a portion of the leading hemisphere of Jupiter's moon Callisto as seen through the infrared filters of the Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft. North is to the top of the picture and the sun illuminates the surface from the east. More recent impacts have excavated bright, relatively clean ice from beneath Callisto's battered surface. Callisto's dark mottled appearance may be due to contamination by non-ice components contributed by impactors or concentrated in a residue as ice is removed. This color composite image is centered on longitude 139 West and encompasses an area about 1000 miles (1600 kilometers) by 2470 miles (4000 kilometers). The images were obtained on November 3rd, 1996.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  3. HEMISPHERIC CENTER FOR ENVIRONMENTAL TECHNOLOGY

    SciTech Connect

    M.A. Ebadian

    1999-10-31

    The Deactivation and Decommissioning (D&D) Technology Assessment Program (TAP) was developed to provide detailed, comparable data for environmental technologies and to disseminate this data to D&D professionals in a manner that will facilitate the review and selection of technologies to perform decontamination and decommissioning. The objectives for this project include the following: Determine technology needs through review of the Site Technology Coordination Group (STCG) information and other applicable websites and needs databases; Perform a detailed review of industries that perform similar activities as those required in D&D operations to identify additional technologies; Define the technology assessment program for characterization and waste management problem sets; Define the data management program for characterization, dismantlement, and waste management problem sets; Evaluate baseline and innovative technologies under standard test conditions at Florida International University's Hemispheric Center for Environmental Technology (FIU-HCET) and other locations and collect data in the areas of performance, cost, health and safety, operations and maintenance, and primary and secondary waste generation; Continue to locate, verify, and incorporate technology performance data from other sources into the multimedia information system; and Develop the conceptual design for a dismantlement technology decision analysis tool for dismantlement technologies.

  4. Hemispheric sunspot unit area: comparison with hemispheric sunspot number and sunspot area

    SciTech Connect

    Li, K. J.; Xiang, N. B.; Qu, Z. N.; Xie, J. L.

    2014-03-01

    The monthly mean northern and southern hemispheric sunspot numbers (SNs) and sunspot areas (SAs) in the time interval of 1945 January to 2012 December are utilized to construct the monthly northern and southern hemispheric sunspot unit areas (SUAs), which are defined as the ratio of hemispheric SA to SN. Hemispheric SUAs are usually found to rise at the beginning and to fall at the ending time of a solar cycle more rapidly, forming a more irregular cycle profile than hemispheric SNs and SAs, although it also presents Schwabe-cycle-like hemispheric SNs and SAs. Sunspot activity (SN, SA, and SUA) is found asynchronously and is asymmetrically distributed in the northern and southern hemispheres, and hemispheric SNs, SAs, and SUAs are not in phase in the two hemispheres. The similarity of hemispheric SNs and SAs is found to be much more obvious than that of hemispheric SUAs and SNs (or SAs), and also for their north-south asymmetry. A notable feature is found for the behavior of the SUA around the minimum time of cycle 24: the SUA rapidly decreases from the cycle maximum value to the cycle minimum value of sunspot cycles 19-24 within just 22 months.

  5. Northern hemisphere dust storms on Mars

    NASA Technical Reports Server (NTRS)

    James, P. B.

    1993-01-01

    Dust storms in the northern hemisphere of Mars appear to be less common than the more familiar southern hemisphere storms, and essentially, no activity north of about 30 latittude has been documented. The data are, however, subject to an observational bias because Mars is near aphelion during oppositions, which occur during the most likely seasons for dust activity in the north. The amount of dust activity in the northern hemisphere is clearly very relevant to the role of atmospheric transport in the dust cycle. The classic global storms that occur during spring in the southern hemisphere are observed to transport dust from sources in the southern hemisphere to sinks or temporary depositories in the north. The question of whether atmospheric transport can close the dust cycle, i.e., return the dust to the southern hemisphere sources on some timescale, is clearly relevant to the solution of the puzzle of how the dust storm cycle is modulated, i.e., why storms occur in some years but not in others. There are data that suggest that the spring/early summer season in the northern hemisphere of Mars during the year following the major 1977 storms observed by Viking was very dusty. A number of observations of the vicinity of the receding north polar cap showed clear evidence of substantial dust activity in the sub-Arctic region.

  6. Hemispheric Asymmetries in Substorm Recovery Time Scales

    NASA Technical Reports Server (NTRS)

    Fillingim, M. O.; Chua, D H.; Germany, G. A.; Spann, James F.

    2009-01-01

    Previous statistical observations have shown that the recovery time scales of substorms occurring in the winter and near equinox (when the nighttime auroral zone was in darkness) are roughly twice as long as the recovery time scales for substorms occurring in the summer (when the nighttime auroral region was sunlit). This suggests that auroral substorms in the northern and southern hemispheres develop asymmetrically during solstice conditions with substorms lasting longer in the winter (dark) hemisphere than in the summer (sunlit) hemisphere. Additionally, this implies that more energy is deposited by electron precipitation in the winter hemisphere than in the summer one during substorms. This result, coupled with previous observations that have shown that auroral activity is more common when the ionosphere is in darkness and is suppressed when the ionosphere is in daylight, strongly suggests that the ionospheric conductivity plays an important role governing how magnetospheric energy is transferred to the ionosphere during substorms. Therefore, the ionosphere itself may dictate how much energy it will accept from the magnetosphere during substorms rather than this being an externally imposed quantity. Here, we extend our earlier work by statistically analyzing the recovery time scales for a large number of substorms observed in the conjugate hemispheres simultaneously by two orbiting global auroral imagers: Polar UVI and IMAGE FUV. Our current results are consistent with previous observations. The recovery time scales are observed to be longer in the winter (dark) hemisphere while the auroral activity has a shorter duration in the summer (sunlit) hemisphere. This leads to an asymmetric energy input from the magnetosphere to the ionosphere with more energy being deposited in the winter hemisphere than in the summer hemisphere.

  7. Mind the gaps: investigating the cause of the current range disjunction in the Cape Platanna, Xenopus gilli (Anura: Pipidae)

    PubMed Central

    Fogell, Deborah J.; Tolley, Krystal A.

    2013-01-01

    Low-lying areas of the Cape at Africa’s south-westernmost tip have undergone dramatic marine-remodelling, with regular changes in sea-level following glacial cycles. Species for which marine barriers are impenetrable underwent concomitant radical distribution changes which may account for current range disjunctions. The Cape platanna, Xenopus gilli, is a frog distributed in only three disjunt areas within low-lying regions of the southwestern Cape. We determined the relationship between frogs from these three disjunct areas, by using a combination of morphometric analysis and mtDNA (ND2 and 16S fragments) sequences of 130 frogs from eight ponds. Coalescent analyses on molecular data dated the divergence in two major clades to around 4.6 Mya, a period during which major uplifting on the eastern side of the subcontinent caused climate changes throughout southern Africa. Principal components analysis showed significant morphometric differences between each clade on head and limb measurements. Consistent differences in ventral colouration and patterning were also observed. We report on increased levels of hybridisation with X. laevis throughout the range of X. gilli, which reaches at least 27% hybrids in some ponds. Urgent conservation actions are required to control habitat loss from alien invasive vegetation, and prevent introgression with the domestic-exotic, X. laevis. PMID:24109551

  8. Securin and not CDK1/cyclin B1 regulates sister chromatid disjunction during meiosis II in mouse eggs.

    PubMed

    Nabti, Ibtissem; Reis, Alexandra; Levasseur, Mark; Stemmann, Olaf; Jones, Keith T

    2008-09-15

    Mammalian eggs remain arrested at metaphase of the second meiotic division (metII) for an indeterminate time before fertilization. During this period, which can last several hours, the continued attachment of sister chromatids is thought to be achieved by inhibition of the protease separase. Separase is known to be inhibited by binding either securin or Maturation (M-Phase)-Promoting Factor, a heterodimer of CDK1/cyclin B1. However, the relative contribution of securin and CDK/cyclin B1 to sister chromatid attachment during metII arrest has not been assessed. Although there are conditions in which either CDK1/cyclinB1 activity or securin can prevent sister chromatid disjunction, principally by overexpression of non-degradable cyclin B1 or securin, we find here that separase activity is primarily regulated by securin and not CDK1/cyclin B1. Thus the CDK1 inhibitor roscovitine and an antibody we designed to block the interaction of CDK1/cyclin B1 with separase, both failed to induce sister disjunction. In contrast, securin morpholino knockdown specifically induced loss of sister attachment, that could be restored by securin cRNA rescue. During metII arrest separase appears primarily regulated by securin binding, not CDK1/cyclin B1. PMID:18639540

  9. Compact Autonomous Hemispheric Vision System

    NASA Technical Reports Server (NTRS)

    Pingree, Paula J.; Cunningham, Thomas J.; Werne, Thomas A.; Eastwood, Michael L.; Walch, Marc J.; Staehle, Robert L.

    2012-01-01

    Solar System Exploration camera implementations to date have involved either single cameras with wide field-of-view (FOV) and consequently coarser spatial resolution, cameras on a movable mast, or single cameras necessitating rotation of the host vehicle to afford visibility outside a relatively narrow FOV. These cameras require detailed commanding from the ground or separate onboard computers to operate properly, and are incapable of making decisions based on image content that control pointing and downlink strategy. For color, a filter wheel having selectable positions was often added, which added moving parts, size, mass, power, and reduced reliability. A system was developed based on a general-purpose miniature visible-light camera using advanced CMOS (complementary metal oxide semiconductor) imager technology. The baseline camera has a 92 FOV and six cameras are arranged in an angled-up carousel fashion, with FOV overlaps such that the system has a 360 FOV (azimuth). A seventh camera, also with a FOV of 92 , is installed normal to the plane of the other 6 cameras giving the system a > 90 FOV in elevation and completing the hemispheric vision system. A central unit houses the common electronics box (CEB) controlling the system (power conversion, data processing, memory, and control software). Stereo is achieved by adding a second system on a baseline, and color is achieved by stacking two more systems (for a total of three, each system equipped with its own filter.) Two connectors on the bottom of the CEB provide a connection to a carrier (rover, spacecraft, balloon, etc.) for telemetry, commands, and power. This system has no moving parts. The system's onboard software (SW) supports autonomous operations such as pattern recognition and tracking.

  10. Hemispherical color differences on Pluto and Charon

    NASA Technical Reports Server (NTRS)

    Binzel, Richard P.

    1988-01-01

    Time-resolved multicolor photometric observations of Pluto-Charon mutual events have been used to derive individual colors for these two bodies and to investigate the degree of color differences between their synchronous facing and opposite hemispheres. Pluto is significantly redder than Charon, where direct measurements of the anti-Charon hemisphere of Pluto and the Pluto-facing hemisphere of Charon yield B-V magnitudes of 0.867 + or - 0.008 and 0.700 + or - 0.010, respectively. Both Pluto and Charon are found to have relatively uniform longitudinal color distributions with 1-sigma upper limits of 2 percent and 5 percent, respectively, for any large-scale hemispherical color asymmetries. Thus, a previous suspicion of a significant color asymmetry on Charon is not confirmed. Instead the data may be attributed to a direct detection of polar caps on Pluto.

  11. Huge Filament Rises From Sun's Northern Hemisphere

    NASA Video Gallery

    On August 1, 2010 following a C3-class solar flare from sunspot 1092, an enormous magnetic filament stretching across the sun's northern hemisphere erupted. This 304 angstrom video shows that filam...

  12. Recovering two languages with the right hemisphere.

    PubMed

    Marini, Andrea; Galetto, Valentina; Tatu, Karina; Duca, Sergio; Geminiani, Giuliano; Sacco, Katiuscia; Zettin, Marina

    2016-08-01

    Converging evidence suggests that the right hemisphere (RH) plays an important role in language recovery from aphasia after a left hemisphere (LH) lesion. In this longitudinal study we describe the neurological, cognitive, and linguistic profile of A.C., a bilingual who, after a severe traumatic brain injury, developed a form of fluent aphasia that affected his two languages (i.e., Romanian and Italian). The trauma-induced parenchymal atrophy led to an exceptional ventricular dilation that, gradually, affected the whole left hemisphere. A.C. is now recovering both languages relying only on his right hemisphere. An fMRI experiment employing a bilingual covert verb generation task documented the involvement of the right middle temporal gyrus in processes of lexical selection and access. This case supports the hypothesis that the RH plays a role in language recovery from aphasia when the LH has suffered massive lesions. PMID:27289209

  13. Southern Hemisphere Polygonal Patterned Ground

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On Earth, periglacial is a term that refers to regions and processes where cold climate contributes to the evolution of landforms and landscapes. Common in periglacial environments on Earth, such as the arctic of northern Canada,Siberia, and Alaska, is a phenomenon called patterned ground. The 'patterns' in patterned ground often take the form of large polygons, each bounded by either troughs or ridges made up of rock particles different in size from those seen in the interior of the polygon. On Earth, many polygons in periglacial environments are directly linked to water: they typically form from stresses induced by repeated freezing and thawing of water, contraction from stress induced by changing temperatures, and sorting of rocks brought to the surface along polygon boundaries by the freeze-thaw processes. Although not exclusively formed by freezing and thawing of water, that is often the dominant mechanism on Earth.

    Polygons similar to those found in Earth's arctic and antarctic regions are also found in the polar regions of Mars. Typically, they occur on crater floors, or on intercrater plains, between about 60o and 80o latitude. The polygons are best seen when bright frost or dark sand has been trapped in the troughs that form the polygon boundaries. Three examples of martian polygons seen by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) are shown here. Each is located in the southern hemisphere:(left) Polygon troughs highlighted by frost as the south polar cap retreats during spring. The circular features are the locations of buried craters that were originally formed by meteor impact. This image, E09-00029, is located at 75.1oS, 331.3oW, and was acquired on 1 October 2001.(center) Summertime view of polygons, highlighted by dark, windblown sand, on the floor of a crater at 71.2oS, 282.6oW. The image, E12-02319, was obtained on 21January 2002.(right) Polygon troughs highlighted by the retreating south polar frost cap during southern summer

  14. The Utilization during Mitotic Cell Division of Loci Controlling Meiotic Recombination and Disjunction in DROSOPHILA MELANOGASTER

    PubMed Central

    Baker, Bruce S.; Carpenter, Adelaide T. C.; Ripoll, P.

    1978-01-01

    To inquire whether the loci identified by recombination-defective and disjunction-defective meiotic mutants in Drosophila are also utilized during mitotic cell division, the effects of 18 meiotic mutants (representing 13 loci) on mitotic chromosome stability have been examined genetically. To do this, meiotic-mutant-bearing flies heterozygous for recessive somatic cell markers were examined for the frequencies and types of spontaneous clones expressing the cell markers. In such flies, marked clones can arise via mitotic recombination, mutation, chromosome breakage, nondisjunction or chromosome loss, and clones from these different origins can be distinguished. In addition, meiotic mutants at nine loci have been examined for their effects on sensitivity to killing by UV and X rays.—Mutants at six of the seven recombination-defective loci examined (mei-9, mei-41, c(3)G, mei-W68, mei-S282, mei-352, mei-218) cause mitotic chromosome instability in both sexes, whereas mutants at one locus (mei-218) do not affect mitotic chromosome stability. Thus many of the loci utilized during meiotic recombination also function in the chromosomal economy of mitotic cells.—The chromosome instability produced by mei-41 alleles is the consequence of chromosome breakage, that of mei-9 alleles is primarily due to chromosome breakage and, to a lesser extent, to an elevated frequency of mitotic recombination, whereas no predominant mechanism responsible for the instability caused by c(3)G alleles is discernible. Since these three loci are defective in their responses to mutagen damage, their effects on chromosome stability in nonmutagenized cells are interpreted as resulting from an inability to repair spontaneous lesions. Both mei-W68 and mei-S282 increase mitotic recombination (and in mei-W68, to a lesser extent, chromosome loss) in the abdomen but not the wing. In the abdomen, the primary effect on chromosome stability occurs during the larval period when the abdominal histoblasts

  15. The Genome of a Southern Hemisphere Seagrass Species (Zostera muelleri).

    PubMed

    Lee, HueyTyng; Golicz, Agnieszka A; Bayer, Philipp E; Jiao, Yuannian; Tang, Haibao; Paterson, Andrew H; Sablok, Gaurav; Krishnaraj, Rahul R; Chan, Chon-Kit Kenneth; Batley, Jacqueline; Kendrick, Gary A; Larkum, Anthony W D; Ralph, Peter J; Edwards, David

    2016-09-01

    Seagrasses are marine angiosperms that evolved from land plants but returned to the sea around 140 million years ago during the early evolution of monocotyledonous plants. They successfully adapted to abiotic stresses associated with growth in the marine environment, and today, seagrasses are distributed in coastal waters worldwide. Seagrass meadows are an important oceanic carbon sink and provide food and breeding grounds for diverse marine species. Here, we report the assembly and characterization of the Zostera muelleri genome, a southern hemisphere temperate species. Multiple genes were lost or modified in Z. muelleri compared with terrestrial or floating aquatic plants that are associated with their adaptation to life in the ocean. These include genes for hormone biosynthesis and signaling and cell wall catabolism. There is evidence of whole-genome duplication in Z. muelleri; however, an ancient pan-commelinid duplication event is absent, highlighting the early divergence of this species from the main monocot lineages. PMID:27373688

  16. Northern Hemisphere forcing of Southern Hemisphere climate during the last deglaciation.

    PubMed

    He, Feng; Shakun, Jeremy D; Clark, Peter U; Carlson, Anders E; Liu, Zhengyu; Otto-Bliesner, Bette L; Kutzbach, John E

    2013-02-01

    According to the Milankovitch theory, changes in summer insolation in the high-latitude Northern Hemisphere caused glacial cycles through their impact on ice-sheet mass balance. Statistical analyses of long climate records supported this theory, but they also posed a substantial challenge by showing that changes in Southern Hemisphere climate were in phase with or led those in the north. Although an orbitally forced Northern Hemisphere signal may have been transmitted to the Southern Hemisphere, insolation forcing can also directly influence local Southern Hemisphere climate, potentially intensified by sea-ice feedback, suggesting that the hemispheres may have responded independently to different aspects of orbital forcing. Signal processing of climate records cannot distinguish between these conditions, however, because the proposed insolation forcings share essentially identical variability. Here we use transient simulations with a coupled atmosphere-ocean general circulation model to identify the impacts of forcing from changes in orbits, atmospheric CO(2) concentration, ice sheets and the Atlantic meridional overturning circulation (AMOC) on hemispheric temperatures during the first half of the last deglaciation (22-14.3 kyr BP). Although based on a single model, our transient simulation with only orbital changes supports the Milankovitch theory in showing that the last deglaciation was initiated by rising insolation during spring and summer in the mid-latitude to high-latitude Northern Hemisphere and by terrestrial snow-albedo feedback. The simulation with all forcings best reproduces the timing and magnitude of surface temperature evolution in the Southern Hemisphere in deglacial proxy records. AMOC changes associated with an orbitally induced retreat of Northern Hemisphere ice sheets is the most plausible explanation for the early Southern Hemisphere deglacial warming and its lead over Northern Hemisphere temperature; the ensuing rise in atmospheric CO(2

  17. Biogeographic implications of the striking discovery of a 4000 kilometer disjunct population of the wild potato Solanum morelliforme in South America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solanum morelliforme is an epiphytic wild potato (Solanum section Petota) species widely distributed throughout central Mexico to Honduras. A strikingly disjunct (4000 km) population was recently discovered in Bolivia, representing the first record of this species in South America. Our maximum entro...

  18. Meiotic disjunction and embryonic lethality in sex-linked double-translocation heterozygous males of the onion fly, Hylemya antiqua (Meigen).

    PubMed

    Vosselman, L; van Heemert, C

    1980-05-01

    The frequencies of disjunction types in double-translocation heterozygous males (2(6)2(Y)6(2)6XY(2)) in Hylemya antiqua have been established in MII cells and eggs of testcrosses.Several disjunction types occurred but four predominated. A correlation was found between the frequencies of the disjunction types and the relative position of the centromeres. The frequency of numerical non-disjunction (NND) was 4%. Differences in frequency of NND between sex-linked and autosomal translocations of H. antiqua are discussed. A good correspondence between the frequencies of unbalanced karyotypes, and embryonic and larval mortality was found. The total genetic load which can be induced by the T14/T61 males is estimated to be 60-65%. Some duplication/deficiency karyotypes appeared to be viable in pupal and even adult stages. In 2(6)2(6)2(Y)6(2)6(2)X males a regular coorientation between 2(Y) and X was observed, in spite of non-homologous centromeres and a complicated synapsis of 2(Y). Application possibilities of the present material for genetic control of H. antiqua are discussed. PMID:24301348

  19. A new disjunct eddy-covariance system for BVOC flux measurements - validation on CO2 and H2O fluxes

    NASA Astrophysics Data System (ADS)

    Baghi, R.; Durand, P.; Jambert, C.; Jarnot, C.; Delon, C.; Serça, D.; Striebig, N.; Ferlicoq, M.; Keravec, P.

    2012-12-01

    The disjunct eddy covariance (DEC) method is an interesting alternative to the conventional eddy covariance (EC) method because it allows the estimation of turbulent fluxes of species for which fast sensors are not available. We have developed and validated a new disjunct sampling system (called MEDEE). This system is built with chemically inert materials. Air samples are taken quickly and alternately in two cylindrical reservoirs, the internal pressures of which are regulated by a moving piston. The MEDEE system was designed to be operated either on the ground or aboard an aircraft. It is also compatible with most analysers since it transfers the air samples at a regulated pressure. To validate the system, DEC and EC measurements of CO2 and latent heat fluxes were performed concurrently during a field campaign. EC fluxes were first compared to simulated DEC (SDEC) fluxes and then to actual DEC fluxes. Both the simulated and actual DEC fluxes showed a good agreement with EC fluxes in terms of correlation. The determination coefficients (R2) were 0.93 and 0.91 for DEC and SDEC latent heat fluxes, respectively. For DEC and SDEC CO2 fluxes R2 was 0.69 in both cases. The conditions of low fluxes experienced during the campaign impaired the comparison of the different techniques especially for CO2 flux measurements. Linear regression analysis showed an 14% underestimation of DEC fluxes for both CO2 and latent heat compared to EC fluxes. A first field campaign, focusing on biogenic volatile organic compound (BVOC) emissions, was carried out to measure isoprene fluxes above a downy oak (Quercus Pubescens) forest in the south-east of France. The measured standard emission rate was in the lower range of reported values in earlier studies. Further analysis will be conducted through ground-based and airborne campaigns in the coming years.

  20. Molecular Biogeography of Tribe Thermopsideae (Leguminosae): A Madrean-Tethyan Disjunction Pattern with an African Origin of Core Genistoides

    PubMed Central

    Zhang, Ming-Li; Huang, Jian-Feng; Sanderson, Stewart C.; Yan, Ping; Wu, Yu-Hu; Pan, Bo-Rong

    2015-01-01

    Thermopsideae has 45 species and exhibits a series of interesting biogeographical distribution patterns, such as Madrean-Tethyan disjunction and East Asia-North America disjunction, with a center of endemism in the Qinghai-Xizang Plateau (QTP) and Central Asia. Phylogenetic analysis in this paper employed maximum likelihood using ITS, rps16, psbA-trnH, and trnL-F sequence data; biogeographical approaches included BEAST molecular dating and Bayesian dispersal and vicariance analysis (S-DIVA). The results indicate that the core genistoides most likely originated in Africa during the Eocene to Oligocene, ca. 55-30 Ma, and dispersed eastward to Central Asia at ca. 33.47 Ma. The origin of Thermopsideae is inferred as Central Asian and dated to ca. 28.81 Ma. Ammopiptanthus is revealed to be a relic. Birth of the ancestor of Thermopsideae coincided with shrinkage of the Paratethys Sea at ca. 30 Ma in the Oligocene. The Himalayan motion of QTP uplift of ca. 20 Ma most likely drove the diversification between Central Asia and North America. Divergences in East Asia, Central Asia, the Mediterranean, and so forth, within Eurasia, except for Ammopiptanthus, are shown to be dispersals from the QTP. The onset of adaptive radiation at the center of the tribe, with diversification of most species in Thermopsis and Piptanthus at ca. 4-0.85 Ma in Tibet and adjacent regions, seems to have resulted from intense northern QTP uplift during the latter Miocene to Pleistocene. PMID:26114116

  1. A right hemisphere dominance for bimanual grasps.

    PubMed

    Le, Ada; Niemeier, Matthias

    2013-01-01

    To find points on the surface of an object that ensure a stable grasp, it would be most effective to employ one area in one cortical hemisphere. But grasping the object with both hands requires control through both hemispheres. To better understand the control mechanisms underlying this "bimanual grasping", here we examined how the two hemispheres coordinate their control processes for bimanual grasping depending on visual field. We asked if bimanual grasping involves both visual fields equally or one more than the other. To test this, participants fixated either to the left or right of an object and then grasped or pushed it off a pedestal. We found that when participants grasped the object in the right visual field, maximum grip aperture (MGA) was larger and more variable, and participants were slower to react and to show MGA compared to when they grasped the object in the left visual field. In contrast, when participants pushed the object we observed no comparable visual field effects. These results suggest that grasping with both hands, specifically the computation of grasp points on the object, predominantly involves the right hemisphere. Our study provides new insights into the interactions of the two hemispheres for grasping. PMID:23109083

  2. Hemispheric lateralization of semantic feature distinctiveness

    PubMed Central

    Reilly, M.; Machado, N.; Blumstein, S. E.

    2015-01-01

    Recent models of semantic memory propose that the semantic representation of concepts is based, in part, on a network of features. In this view, a feature that is distinctive for an object (a zebra has stripes) is processed differently from a feature that is shared across many objects (a zebra has four legs). The goal of this paper is to determine whether there are hemispheric differences in such processing. In a feature verification task, participants responded ‘yes’ or ‘no’ following concepts which were presented to a single visual field (left or right) paired with a shared or distinctive feature. Both hemispheres showed faster reaction times to shared features than to distinctive features, although right hemisphere responses were significantly slower overall and particularly in the processing of distinctive features. These findings support models of semantic processing in which the dominant left hemisphere more efficiently performs highly discriminating ‘fine’ encoding, in contrast to the right hemisphere which performs less discriminating ‘coarse’ encoding. PMID:26022059

  3. Single Mode Lasing from Hybrid Hemispherical Microresonators

    PubMed Central

    Chen, Rui; Van Duong Ta; Sun, Han Dong

    2012-01-01

    Enormous attention has been paid to optical microresonators which hold a great promise for microlasers as well as fundamental studies in cavity quantum electrodynamics. Here we demonstrate a three-dimensional (3D) hybrid microresonator combining self-assembled hemispherical structure with a planar reflector. By incorporating dye molecules into the hemisphere, optically pumped lasing phenomenon is observed at room temperature. We have studied the lasing behaviors with different cavity sizes, and particularly single longitudinal mode lasing from hemispheres with diameter ∼15 μm is achieved. Detailed characterizations indicate that the lasing modes shift under varying pump densities, which can be well-explained by frequency shift and mode hopping. This work provides a versatile approach for 3D confined microresonators and opens an opportunity to realize tunable single mode microlasers. PMID:22540027

  4. Right hemisphere grey matter structure and language outcomes in chronic left hemisphere stroke.

    PubMed

    Xing, Shihui; Lacey, Elizabeth H; Skipper-Kallal, Laura M; Jiang, Xiong; Harris-Love, Michelle L; Zeng, Jinsheng; Turkeltaub, Peter E

    2016-01-01

    The neural mechanisms underlying recovery of language after left hemisphere stroke remain elusive. Although older evidence suggested that right hemisphere language homologues compensate for damage in left hemisphere language areas, the current prevailing theory suggests that right hemisphere engagement is ineffective or even maladaptive. Using a novel combination of support vector regression-based lesion-symptom mapping and voxel-based morphometry, we aimed to determine whether local grey matter volume in the right hemisphere independently contributes to aphasia outcomes after chronic left hemisphere stroke. Thirty-two left hemisphere stroke survivors with aphasia underwent language assessment with the Western Aphasia Battery-Revised and tests of other cognitive domains. High-resolution T1-weighted images were obtained in aphasia patients and 30 demographically matched healthy controls. Support vector regression-based multivariate lesion-symptom mapping was used to identify critical language areas in the left hemisphere and then to quantify each stroke survivor's lesion burden in these areas. After controlling for these direct effects of the stroke on language, voxel-based morphometry was then used to determine whether local grey matter volumes in the right hemisphere explained additional variance in language outcomes. In brain areas in which grey matter volumes related to language outcomes, we then compared grey matter volumes in patients and healthy controls to assess post-stroke plasticity. Lesion-symptom mapping showed that specific left hemisphere regions related to different language abilities. After controlling for lesion burden in these areas, lesion size, and demographic factors, grey matter volumes in parts of the right temporoparietal cortex positively related to spontaneous speech, naming, and repetition scores. Examining whether domain general cognitive functions might explain these relationships, partial correlations demonstrated that grey matter

  5. Genetic variability of Spodoptera frugiperda (Lepidoptera: Noctuidae) in the Western Hemisphere

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) is a migratory and polyphagous pest of both cultivated and uncultivated plant species in the Western Hemisphere. We investigated the genetic diversity of FAW by collecting 31 representative samples from the United States, Argentina, Panama...

  6. A vision of graded hemispheric specialization.

    PubMed

    Behrmann, Marlene; Plaut, David C

    2015-11-01

    Understanding the process by which the cerebral hemispheres reach their mature functional organization remains challenging. We propose a theoretical account in which, in the domain of vision, faces and words come to be represented adjacent to retinotopic cortex by virtue of the need to discriminate among homogeneous exemplars. Orthographic representations are further constrained to be proximal to typically left-lateralized language-related information to minimize connectivity length between visual and language areas. As reading is acquired, orthography comes to rely more heavily (albeit not exclusively) on the left fusiform region to bridge vision and language. Consequently, due to competition from emerging word representations, face representations that were initially bilateral become lateralized to the right fusiform region (albeit, again, not exclusively). We review recent research that describes constraints that give rise to this graded hemispheric arrangement. We then summarize empirical evidence from a variety of studies (behavioral, evoked response potential, functional imaging) across different populations (children, adolescents, and adults; left handers and individuals with developmental dyslexia) that supports the claims that hemispheric lateralization is graded rather than binary and that this graded organization emerges dynamically over the course of development. Perturbations of this system either during development or in adulthood provide further insights into the principles governing hemispheric organization. PMID:26199998

  7. Meaning Apprehension in the Cerebral Hemispheres

    ERIC Educational Resources Information Center

    Kandhadai, Padmapriya A.

    2009-01-01

    When we hear a word, it is remarkable how we store, activate and rapidly retrieve a vast amount of relevant information within a few hundred milliseconds. This thesis examines how meaning is processed in parallel--but with critical differences--between the two hemispheres of the brain. Event-related brain potentials (ERP) were used to examine…

  8. Right Hemisphere Specialization for Color Detection

    ERIC Educational Resources Information Center

    Sasaki, Hitoshi; Morimoto, Akiko; Nishio, Akira; Matsuura, Sumie

    2007-01-01

    Three experiments were carried out to investigate hemispheric asymmetry in color processing among normal participants. In Experiment 1, it was shown that the reaction times (RTs) of the dominant and non-dominant hands assessed using a visual target presented at the central visual field, were not significantly different. In Experiment 2, RTs of…

  9. Hemispheric differences in the mesostriatal dopaminergic system

    PubMed Central

    Molochnikov, Ilana; Cohen, Dana

    2014-01-01

    The mesostriatal dopaminergic system, which comprises the mesolimbic and the nigrostriatal pathways, plays a major role in neural processing underlying motor and limbic functions. Multiple reports suggest that these processes are influenced by hemispheric differences in striatal dopamine (DA) levels, DA turnover and its receptor activity. Here, we review studies which measured the concentration of DA and its metabolites to examine the relationship between DA imbalance and animal behavior under different conditions. Specifically, we assess evidence in support of endogenous, inter-hemispheric DA imbalance; determine whether the known anatomy provides a suitable substrate for this imbalance; examine the relationship between DA imbalance and animal behavior; and characterize the symmetry of the observed inter-hemispheric laterality in the nigrostriatal and the mesolimbic DA systems. We conclude that many studies provide supporting evidence for the occurrence of experience-dependent endogenous DA imbalance which is controlled by a dedicated regulatory/compensatory mechanism. Additionally, it seems that the link between DA imbalance and animal behavior is better characterized in the nigrostriatal than in the mesolimbic system. Nonetheless, a variety of brain and behavioral manipulations demonstrate that the nigrostriatal system displays symmetrical laterality whereas the mesolimbic system displays asymmetrical laterality which supports hemispheric specialization in rodents. The reciprocity of the relationship between DA imbalance and animal behavior (i.e., the capacity of animal training to alter DA imbalance for prolonged time periods) remains controversial, however, if confirmed, it may provide a valuable non-invasive therapeutic means for treating abnormal DA imbalance. PMID:24966817

  10. Hemispheric Differences in Processing Handwritten Cursive

    ERIC Educational Resources Information Center

    Hellige, Joseph B.; Adamson, Maheen M.

    2007-01-01

    Hemispheric asymmetry was examined for native English speakers identifying consonant-vowel-consonant (CVC) non-words presented in standard printed form, in standard handwritten cursive form or in handwritten cursive with the letters separated by small gaps. For all three conditions, fewer errors occurred when stimuli were presented to the right…

  11. Rethinking a Right Hemisphere Deficit in ADHD

    ERIC Educational Resources Information Center

    Hale, T. Sigi; Loo, Sandra K.; Zaidel, Eran; Hanada, Grant; Macion, James; Smalley, Susan L.

    2009-01-01

    Introduction: Early observations from lesion studies suggested right hemisphere (RH) dysfunction in ADHD. However, a strictly right-lateralized deficit has not been well supported. An alternatively view suggests increased R greater than L asymmetry of brain function and abnormal interhemispheric interaction. If true, RH pathology in ADHD should…

  12. Hemisphere jet mass distribution at finite Nc

    NASA Astrophysics Data System (ADS)

    Hagiwara, Yoshikazu; Hatta, Yoshitaka; Ueda, Takahiro

    2016-05-01

    We perform the leading logarithmic resummation of nonglobal logarithms for the single-hemisphere jet mass distribution in e+e- annihilation including the finite-Nc corrections. The result is compared with the previous all-order result in the large-Nc limit as well as fixed-order perturbative calculations.

  13. Civilisations of the Left Cerebral Hemisphere?

    ERIC Educational Resources Information Center

    Racle, Gabriel L.

    Research conducted by Tadanobu Tsunoda on auditory and visual sensation, designed to test and understand the functions of the cerebral hemispheres, is discussed. Tsunoda discovered that the Japanese responses to sounds by the left and the right sides of the brain are very different from the responses obtained from people from other countries. His…

  14. Hemisphere and gender differences in mental rotation.

    PubMed

    Uecker, A; Obrzut, J E

    1993-05-01

    Hemisphere and gender differences in mental rotation for tachistoscopically presented stimuli were assessed in 40 right-handed university students. Twenty male and 20 female subjects each were individually administered (via computer) a mental rotation task which included 10 stimulus presentations at each of eight angular disorientations (0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees) in each visual half-field (VHF) for a total of 160 trials. Analyses of variance performed on reaction time and accuracy data revealed only a main effect for orientation. A typical mental rotation function for both the left VHF and the right VHF for both genders resulted; however, no gender x visual field interaction was found. Lack of hemisphere and gender differences provide further evidence questioning the interpretation of right-hemisphere male superiority for spatial tasks. Investigation into factors such as task complexity, stimulus familiarity, and task demands may lend further insight into hemisphere and gender differences in mental rotation. PMID:8499111

  15. Creative Cognitive Processes and Hemispheric Specialization.

    ERIC Educational Resources Information Center

    Poreh, A. M.; Whitman, R. D.

    1991-01-01

    The relationship between creative thought processes and hemispheric asymmetry was examined in 47 right-handed male undergraduates. Four factors were identified, accounting for 75 percent of the total variance: Verbal Divergent Thinking Factor, Nonverbal Divergent Thinking Factor, Convergent Verbal Search Factor, and Cognitive Complexity Factor.…

  16. Hemispheric Coupling: Comparing Dynamo Simulations and Observations

    NASA Astrophysics Data System (ADS)

    Norton, A. A.; Charbonneau, P.; Passos, D.

    2014-12-01

    Numerical simulations that reproduce solar-like magnetic cycles can be used to generate long-term statistics. The variations in north-south hemispheric solar cycle synchronicity and amplitude produced in simulations has not been widely compared to observations. The observed limits on solar cycle amplitude and phase asymmetry show that hemispheric sunspot area production is no more than 20 % asymmetric for cycles 17-23 and that phase lags do not exceed 20 % (or two years) of the total cycle period, as determined from Royal Greenwich Observatory sunspot data. Several independent studies have found a long-term trend in phase values as one hemisphere leads the other for, on average, four cycles. Such persistence in phase is not indicative of a stochastic phenomenon. We compare these observational findings to the magnetic cycle found in a numerical simulation of solar convection recently produced with the EULAG-MHD model. This long "millennium simulation" spans more than 1600 years and generated 40 regular, sunspot-like cycles. While the simulated cycle length is too long (˜40 yrs) and the toroidal bands remain at too high of latitudes (>30°), some solar-like aspects of hemispheric asymmetry are reproduced. The model is successful at reproducing the synchrony of polarity inversions and onset of cycle as the simulated phase lags do not exceed 20 % of the cycle period. The simulated amplitude variations between the north and south hemispheres are larger than those observed in the Sun, some up to 40 %. An interesting note is that the simulations also show that one hemisphere can persistently lead the other for several successive cycles, placing an upper bound on the efficiency of transequatorial magnetic coupling mechanisms. These include magnetic diffusion, cross-equatorial mixing within latitudinally-elongated convective rolls (a.k.a. "banana cells") and transequatorial meridional flow cells. One or more of these processes may lead to magnetic flux cancellation whereby

  17. A new delimitation of the Afro-Eurasian plant genus Althenia to include its Australasian relative, Lepilaena (Potamogetonaceae) - Evidence from DNA and morphological data.

    PubMed

    Ito, Yu; Tanaka, Norio; García-Murillo, Pablo; Muasya, A Muthama

    2016-05-01

    Althenia (Potamogetonaceae) is an aquatic plant genus disjunctly distributed in the southern- (South Africa's Cape Floristic Region: CFR) and northern- (Mediterranean Eurasia) hemispheres. This genus and its Australasian relative, Lepilaena, share similar floral characters yet have been treated as different genera or sections of Althenia sensu lato (s.l.) due to the isolated geographic distribution as well as the differences in sex expression, stamen construction, and stigma morphology. The diagnostic characters, however, need reevaluation over the boundaries between the entities. Here we tested the taxonomic delimitation between the entities, assessed synapomorphies for evolutionary lineages, and inferred biogeographic history in a phylogenetic framework. Our results indicated that Lepilaena was resolved as non-monophyletic in both plastid DNA and nuclear PhyC trees and Althenia was nested within it. As Althenia has nomenclatural priority, we propose a new delimitation to recognize Althenia s.l., which can be diagnosed by the female flowers with 3-segmented perianths and male flowers with perianths. The previously used diagnostic characters are either autapomorphies or synapomorphies for small lineages within Althenia s.l., and evolutionary transitions to sessile female flowers and narrow leaves characterize larger clades. Biogeographic analyses suggested a Miocene origin of Althenia s.l. in Australasia and indicated at least one inter- and one intra-specific inter-continental dispersal events among Australasia, Mediterranean Eurasia, and CFR need to be hypothesized to explain the current distribution patterns. PMID:26899346

  18. A signal detection model predicts the effects of set size on visual search accuracy for feature, conjunction, triple conjunction, and disjunction displays

    NASA Technical Reports Server (NTRS)

    Eckstein, M. P.; Thomas, J. P.; Palmer, J.; Shimozaki, S. S.

    2000-01-01

    Recently, quantitative models based on signal detection theory have been successfully applied to the prediction of human accuracy in visual search for a target that differs from distractors along a single attribute (feature search). The present paper extends these models for visual search accuracy to multidimensional search displays in which the target differs from the distractors along more than one feature dimension (conjunction, disjunction, and triple conjunction displays). The model assumes that each element in the display elicits a noisy representation for each of the relevant feature dimensions. The observer combines the representations across feature dimensions to obtain a single decision variable, and the stimulus with the maximum value determines the response. The model accurately predicts human experimental data on visual search accuracy in conjunctions and disjunctions of contrast and orientation. The model accounts for performance degradation without resorting to a limited-capacity spatially localized and temporally serial mechanism by which to bind information across feature dimensions.

  19. Hemispheric Bias in Earth's response to orbital forcing

    NASA Astrophysics Data System (ADS)

    Roychowdhury, Rajarshi; DeConto, Rob

    2014-05-01

    Today, there is an unequal distribution of land and water between the two hemispheres. The Northern Hemisphere has about 68% of the total landmass on earth, while the Southern hemisphere has less than half of the northern hemisphere land (~32%). It is observed that the Southern Hemisphere climates tend to be slightly milder than those in the Northern Hemisphere at similar latitudes, except in the Antarctic which is colder than the Arctic. This variance in climate can be attributed to two reasons: the current precessional configuration of the earth; and the fact that the Southern Hemisphere has significantly more ocean and much less land. The objective of this paper is to determine a hemispheric bias in climate due to unequal land distribution in the Northern and Southern Hemispheres. In this study, we use physically based climate models to gain insights into the role of Northern Hemisphere landmass distribution affecting the Southern Hemisphere climate and vice versa. We use hypothetical symmetric earth models in which landmass distribution is mirrored along the equator. We use these hypothetical landmass distributions to run a control simulation to provide the boundary conditions for a number of branched runs with a range of modified orbital parameters. The aim is to isolate the effects of the modified landmass distribution from the usual effects of orbital forcing. Using a Northern-Hemisphere symmetric earth model and a Southern-Hemisphere symmetric earth model, we are able to draw conclusions regarding the Northern influence on Southern Hemisphere and vice versa. With this information, a hemispheric bias map is constructed which has the potential to reveal useful insights into many unsolved climate problems. Precession and Obliquity effects are also studied in isolation on the calculated hemispheric bias. An improved understanding of the hemispheric bias caused by continental distribution will help associate past climates to paleocontinental reconstructions with

  20. Benchmark Evaluation of Plutonium Hemispheres Reflected by Steel and Oil

    SciTech Connect

    John Darrell Bess

    2008-06-01

    During the period from June 1967 through September 1969 a series of critical experiments was performed at the Rocky Flats Critical Mass Laboratory with spherical and hemispherical plutonium assemblies as nested hemishells as part of a Nuclear Safety Facility Experimental Program to evaluate operational safety margins for the Rocky Flats Plant. These assemblies were both bare and fully or partially oil-reflected. Many of these experiments were subcritical with an extrapolation to critical configurations or critical at a particular oil height. Existing records reveal that 167 experiments were performed over the course of 28 months. Unfortunately, much of the data was not recorded. A reevaluation of the experiments had been summarized in a report for future experimental and computational analyses. This report examines only fifteen partially oil-reflected hemispherical assemblies. Fourteen of these assemblies also had close-fitting stainless-steel hemishell reflectors, used to determine the effective critical reflector height of oil with varying steel-reflector thickness. The experiments and their uncertainty in keff values were evaluated to determine their potential as valid criticality benchmark experiments of plutonium.

  1. Choosing words: left hemisphere, right hemisphere, or both? Perspective on the lateralization of word retrieval.

    PubMed

    Riès, Stéphanie K; Dronkers, Nina F; Knight, Robert T

    2016-04-01

    Language is considered to be one of the most lateralized human brain functions. Left hemisphere dominance for language has been consistently confirmed in clinical and experimental settings and constitutes one of the main axioms of neurology and neuroscience. However, functional neuroimaging studies are finding that the right hemisphere also plays a role in diverse language functions. Critically, the right hemisphere may also compensate for the loss or degradation of language functions following extensive stroke-induced damage to the left hemisphere. Here, we review studies that focus on our ability to choose words as we speak. Although fluidly performed in individuals with intact language, this process is routinely compromised in aphasic patients. We suggest that parceling word retrieval into its subprocesses-lexical activation and lexical selection-and examining which of these can be compensated for after left hemisphere stroke can advance the understanding of the lateralization of word retrieval in speech production. In particular, the domain-general nature of the brain regions associated with each process may be a helpful indicator of the right hemisphere's propensity for compensation. PMID:26766393

  2. The 2011 Northern Hemisphere Solar Maximum

    NASA Astrophysics Data System (ADS)

    Altrock, Richard C.

    2013-01-01

    Altrock (1997, Solar Phys. 170, 411) discusses a process in which Fe XIV 530.3 nm emission features appear at high latitudes and gradually migrate towards the equator, merging with the sunspot "butterfly diagram". In cycles 21 - 23 solar maximum occurred when the number of Fe XIV emission regions per day > 0.19 (averaged over 365 days and both hemispheres) first reached latitudes 18°, 21° and 21°, for an average of 20° ± 1.7°. Another high-latitude process is the "Rush to the Poles" of polar crown prominences and their associated coronal emission, including Fe XIV. The Rush is a harbinger of solar maximum (cf. Altrock, 2003, Solar Phys. 216, 343). Solar maximum in cycles 21 - 23 occurred when the center line of the Rush reached a critical latitude. These latitudes were 76°, 74° and 78°, respectively, for an average of 76° ± 2°. Cycle 24 displays an intermittent Rush that is only well-defined in the northern hemisphere. In 2009 an initial slope of 4.6°/yr was found in the north, compared to an average of 9.4 ± 1.7 °/yr in the previous three cycles. However, in 2010 the slope increased to 7.5°/yr. Extending that rate to 76° ± 2° indicates that the solar maximum smoothed sunspot number in the northern hemisphere already occurred at 2011.6 ± 0.3. In the southern hemisphere the Rush is very poorly defined. A linear fit to several maxima would reach 76° in the south at 2014.2. In 1999, persistent Fe XIV coronal emission connected with the ESC appeared near 70° in the north and began migrating towards the equator at a rate 40% slower than the previous two solar cycles. A fit to the early ESC would not reach 20° until 2019.8. However, in 2009 and 2010 an acceleration occurred. Currently the greatest number of emission regions is at 21° in the north and 24°in the south. This indicates that solar maximum is occurring now in the north but not yet in the south. The latest global smoothed sunspot numbers show an inflection point in late 2011, which

  3. Characterization of Cep85 – a new antagonist of Nek2A that is involved in the regulation of centrosome disjunction

    PubMed Central

    Chen, Canhe; Tian, Fang; Lu, Lin; Wang, Yun; Xiao, Zhe; Yu, Chengtao; Yu, Xianwen

    2015-01-01

    ABSTRACT Nek2 has been implicated in centrosome disjunction at the onset of mitosis to promote bipolar spindle formation, and hyperactivation of Nek2 leads to the premature centrosome separation. Its activity, therefore, needs to be strictly regulated. In this study, we report that Cep85, an uncharacterized centrosomal protein, acts as a binding partner of Nek2A. It colocalizes with isoform A of Nek2 (Nek2A) at centrosomes and forms a granule meshwork enveloping the proximal ends of centrioles. Opposite to the effects of Nek2A, overexpression of Cep85 in conjunction with inhibition of the motor protein Eg5 (also known as KIF11) leads to the failure of centrosome disjunction. By contrast, depletion of Cep85 results in the precocious centrosome separation. We also define the Nek2A binding and centrosome localization domains within Cep85. Although the Nek2A-binding domain alone is sufficient to inhibit Nek2A kinase activity in vitro, both domains are indispensable for full suppression of centrosome disjunction in cells. Thus, we propose that Cep85 is a bona fide Nek2A-binding partner that surrounds the proximal ends of centrioles where it cooperates with PP1γ (also known as PPP1CC) to antagonize Nek2A activity in order to maintain the centrosome integrity in interphase in mammalian cells. PMID:26220856

  4. Asymmetric auroral intensities in the Earth's Northern and Southern hemispheres

    NASA Astrophysics Data System (ADS)

    Laundal, K. M.; Østgaard, N.

    2009-07-01

    It is commonly assumed that the aurora borealis (Northern Hemisphere) and aurora australis (Southern Hemisphere) are mirror images of each other because the charged particles causing the aurora follow the magnetic field lines connecting the two hemispheres. The particles are believed to be evenly distributed between the two hemispheres, from the source region in the equatorial plane of the magnetosphere. Although it has been shown that similar auroral features in the opposite hemispheres can be displaced tens of degree in longitude and that seasonal effects can cause differences in global intensity, the overall auroral patterns were still similar. Here we report observations that clearly contradict the common assumption about symmetric aurora: intense spots are seen at dawn in the Northern summer Hemisphere, and at dusk in the Southern winter Hemisphere. The asymmetry is interpreted in terms of inter-hemispheric currents related to seasons, which have been predicted but hitherto had not been seen.

  5. Cortical Hemisphere Registration Via Large Deformation Diffeomorphic Metric Curve Mapping

    PubMed Central

    Qiu, Anqi; Miller, Michael I.

    2010-01-01

    We present large deformation diffeomorphic metric curve mapping (LDDMM-Curve) for registering cortical hemispheres. We showed global cortical hemisphere matching and evaluated the mapping accuracy in five subregions of the cortex in fourteen MRI scans. PMID:18051058

  6. Nitrate probability mapping in the northern aquifer alluvial system of the river Tagus (Portugal) using Disjunctive Kriging.

    PubMed

    Mendes, Maria Paula; Ribeiro, Luís

    2010-02-01

    The Water Framework Directive and its daughter directives recognize the urgent need to adopt specific measures against the contamination of water by individual pollutants or a group of pollutants that present a significant risk to the quality of water. Probability maps showing that the nitrate concentrations exceed a legal threshold value in any location of the aquifer are used to assess risk of groundwater quality degradation from intensive agricultural activity in aquifers. In this paper we use Disjunctive Kriging to map the probability that the Nitrates Directive limit (91/676/EEC) is exceeded for the Nitrate Vulnerable Zone of the River Tagus alluvium aquifer. The Tagus alluvial aquifer system belongs to one of the most productive hydrogeological unit of continental Portugal and it is used to irrigate crops. Several groundwater monitoring campaigns were carried out from 2004 to 2006 according to the summer crops cycle. The study reveals more areas on the west bank with higher probabilities of contamination by nitrates (nitrate concentration values above 50mg/L) than on the east bank. The analysis of synthetic temporal probability map shows the areas where there is an increase of nitrates concentration during the summers. PMID:19932915

  7. Inferring the phylogeny of disjunct populations of the azure-winged magpie Cyanopica cyanus from mitochondrial control region sequences.

    PubMed

    Fok, Koon Wah; Wade, Christopher M; Parkin, David T

    2002-08-22

    The azure-winged magpie (AWM), Cyanopica cyanus, is found in Asia and Iberia. This remarkable disjunct distribution has been variously explained by either the sixteenth-century introduction of birds into Iberia from the Far East, or by the loss of individuals from the central part of their range as a result of Pleistocene glaciations. We have used the mitochondrial control region to undertake a molecular phylogenetic analysis of the AWM, with sequences examined from individuals collected from across the current distribution range and incorporating representatives of all currently defined subspecies. The Western birds are genetically distinct from their Asian congeners and their divergence is basal in the phylogenetic tree. This indicates that the AWM is native to Iberia and not the result of a recent introduction from Asia. In Asia, two major mitochondrial DNA lineages were identified. These correspond to an Inland Asia group and a Pacific Seaboard group, and are separated topographically by the Da Hingan Ling mountains and the Yellow Sea. Molecular clock estimates suggest that these divergences are associated with Pleistocene glaciations. Furthermore, our data do not support the current classification of the AWM into 10 subspecies, as defined based on morphology and geographical distribution. PMID:12204127

  8. Electron-energy losses in hemispherical targets

    SciTech Connect

    Aizpurua, J.; Rivacoba, A.; Apell, S.P.

    1996-07-01

    In the framework of classical dielectric theory, the hemispherical geometry is studied. Calculations on surface modes are carried out for isolated Drude-like hemispheres. The convergence of the results with respect to the number of coupled terms in the expressions of the potential is discussed. The electron-energy-loss probability is studied for Al and Ag particles involving this geometry. The surface modes and hence the energy-loss probability are given by coupled expressions, the physical meaning of which is the coupling among multipolar terms, because of the particular geometry. The results obtained here present a good quantitative agreement with experiments in the case of clear surfaces (Ag) and provide a qualitative understanding for the experiments in Al, in terms of the position and impact parameter of the beam. This allows us to set the validity of the dielectric theory for cases that seemed to question it. {copyright} {ital 1996 The American Physical Society.}

  9. Metastability of Northern Hemisphere Teleconnection modes

    NASA Astrophysics Data System (ADS)

    Risbey, James; O'Kane, Terence; Monselesan, Didier; Franzke, Christian; Horenko, Ilia

    2014-05-01

    This work applies the FEM-BV-VARX method to study of the large scale modes of variability in the Northern Hemisphere as manifest in 500hPa geopotential height fields. The FEM-BV-VARX method identifies metastable states of the system. The results for regional domains confirm that the teleconnection modes referred to as the NAO in the Atlantic domain, PNA in the Pacific domain, and Scandanavian blocking in the Eurasian domain, all exhibit metastability. For the full Northern Hemisphere domain the metastable state combines the AO and a midlatitude circumglobal wavetrain pattern. These results are shown in a set of reanalysis products from NCEP; the 20th century reanalysis, NNR1, and the CFSR coupled reanalysis. The reanalysis products are all able to simulate the structure and temporal switching of regime states. Decadal and multidecadal regimes are clearly apparent in the model affiliation sequence of metastable states and correspond to known transition points for the teleconnection modes.

  10. Mesoscale Temperature Fluctuations in the Southern Hemisphere Stratosphere

    NASA Technical Reports Server (NTRS)

    Gary, Bruce L.

    2008-01-01

    Isentrope surfaces in the Southern Hemisphere stratosphere reveal that air parcels undergo mesoscale temperature fluctuations that depend on latitude and season. The largest temperature fluctuations occur at high latitude winter, whereas the smallest fluctuations occur at high latitude summer. This is the same pattern found for the Northern Hemisphere stratosphere. However, the amplitude of the seasonal dependence in the Southern Hemisphere is only 37% of the Northern Hemisphere's seasonal amplitude.

  11. Quaternary glaciations in the Northern Hemisphere

    SciTech Connect

    Sibrava, V.; Bowen, D.Q.; Richmond, G.M.

    1987-01-01

    This volume presents the final report of Project 24 of the International Geological Correlation Programme. The publication is drawn from the contributions of leading individual scientist as well as from scientific research teams. It reflects the present state of knowledge of the Quaternary Glaciations in the Northern Hemisphere and their correlation in space and time, as well as providing a unique summary of climatic change.

  12. Hemispheric modulations of the attentional networks.

    PubMed

    Spagna, Alfredo; Martella, Diana; Fuentes, Luis J; Marotta, Andrea; Casagrande, Maria

    2016-10-01

    Although several recent studies investigated the hemispheric contributions to the attentional networks using the Attention Network Test (ANT), the role of the cerebral hemispheres in modulating the interaction among them remains unclear. In this study, two lateralized versions of this test (LANT) were used to investigate theal effects on the attentional networks under different conflict conditions. One version, the LANTI-A, presented arrows as target and flankers, while the other version, the LANTI-F, had fruits as target and flankers. Data collected from forty-seven participants confirmed well-known results on the efficiency and interactions among the attentional networks. Further, a left visual field advantage was found when a target occurred in an unattended location (e.g. invalid trials), only with the LANTI-F, but not with LANTI-A. The present study adds more evidence to the hemispheric asymmetry of the orienting of attention, and further reveals patterns of interactions between the attentional networks and the visual fields across different conflicting conditions, underlying the dynamic control of attention in complex environments. PMID:27566000

  13. Casimir Effect in Hemisphere Capped Tubes

    NASA Astrophysics Data System (ADS)

    Bezerra de Mello, E. R.; Saharian, A. A.

    2016-02-01

    In this paper we investigate the vacuum densities for a massive scalar field with general curvature coupling in background of a (2 + 1)-dimensional spacetime corresponding to a cylindrical tube with a hemispherical cap. A complete set of mode functions is constructed and the positive-frequency Wightman function is evaluated for both the cylindrical and hemispherical subspaces. On the base of this, the vacuum expectation values of the field squared and energy-momentum tensor are investigated. The mean field squared and the normal stress are finite on the boundary separating two subspaces, whereas the energy density and the parallel stress diverge as the inverse power of the distance from the boundary. For a conformally coupled field, the vacuum energy density is negative on the cylindrical part of the space. On the hemisphere, it is negative near the top and positive close to the boundary. In the case of minimal coupling the energy density on the cup is negative. On the tube it is positive near the boundary and negative at large distances. Though the geometries of the subspaces are different, the Casimir pressures on the separate sides of the boundary are equal and the net Casimir force vanishes. The results obtained may be applied to capped carbon nanotubes described by an effective field theory in the long-wavelength approximation.

  14. Bio-inspired hemispherical compound eye camera

    NASA Astrophysics Data System (ADS)

    Xiao, Jianliang; Song, Young Min; Xie, Yizhu; Malyarchuk, Viktor; Jung, Inhwa; Choi, Ki-Joong; Liu, Zhuangjian; Park, Hyunsung; Lu, Chaofeng; Kim, Rak-Hwan; Li, Rui; Crozier, Kenneth B.; Huang, Yonggang; Rogers, John A.

    2014-03-01

    Compound eyes in arthropods demonstrate distinct imaging characteristics from human eyes, with wide angle field of view, low aberrations, high acuity to motion and infinite depth of field. Artificial imaging systems with similar geometries and properties are of great interest for many applications. However, the challenges in building such systems with hemispherical, compound apposition layouts cannot be met through established planar sensor technologies and conventional optics. We present our recent progress in combining optics, materials, mechanics and integration schemes to build fully functional artificial compound eye cameras. Nearly full hemispherical shapes (about 160 degrees) with densely packed artificial ommatidia were realized. The number of ommatidia (180) is comparable to those of the eyes of fire ants and bark beetles. The devices combine elastomeric compound optical elements with deformable arrays of thin silicon photodetectors, which were fabricated in the planar geometries and then integrated and elastically transformed to hemispherical shapes. Imaging results and quantitative ray-tracing-based simulations illustrate key features of operation. These general strategies seem to be applicable to other compound eye devices, such as those inspired by moths and lacewings (refracting superposition eyes), lobster and shrimp (reflecting superposition eyes), and houseflies (neural superposition eyes).

  15. Hemisphericity Research: An Overview with Some Implications for Problem Solving.

    ERIC Educational Resources Information Center

    Myers, John T.

    1982-01-01

    Research on cerebral hemisphericity and lateral dominance is reviewed, and relationships between right and left hemispheric modes of information processing as well as problem solving techniques are discussed. Conclusions focus mainly on need for educators to know information processing differences of the two hemispheres to teach children problem…

  16. The Influence of Context on Hemispheric Recruitment during Metaphor Processing

    ERIC Educational Resources Information Center

    Diaz, Michele T.; Hogstrom, Larson J.

    2011-01-01

    Although the left hemisphere's prominence in language is well established, less emphasis has been placed on possible roles for the right hemisphere. Behavioral, patient, and neuroimaging research suggests that the right hemisphere may be involved in processing figurative language. Additionally, research has demonstrated that context can modify…

  17. Evidence for Right Hemisphere Phonology in a Backward Masking Task

    ERIC Educational Resources Information Center

    Halderman, Laura K.

    2011-01-01

    The extent to which orthographic and phonological processes are available during the initial moments of word recognition within each hemisphere is under specified, particularly for the right hemisphere. Few studies have investigated whether each hemisphere uses orthography and phonology under constraints that restrict the viewing time of words and…

  18. Flexible Contrast Gain Control in the Right Hemisphere

    ERIC Educational Resources Information Center

    Okubo, Matia; Nicholls, Michael E. R.

    2005-01-01

    This study investigates whether the right hemisphere has more flexible contrast gain control settings for the identification of spatial frequency. Right-handed participants identified 1 and 9 cycles per degree sinusoidal gratings presented either to the left visual field-right hemisphere (LVF-RH) or the right visual field-left hemisphere (RVF-LH).…

  19. Hemisphericity, Cognitive Set, and Susceptibility to Subliminal Perception

    ERIC Educational Resources Information Center

    Sackeim, Harold A.; And Others

    1977-01-01

    Examines the role of hemisphericity, that is, the tendency habitually to activate one or the other cerebral hemispheres regardless of the appropriateness of that hemisphere for task demands, and cognitive set as moderating variables in susceptibility to subliminal perception. (Author/RK)

  20. Brain Hemisphere Dominance: Building the Whole-Brain Singer

    ERIC Educational Resources Information Center

    Boyd, Amanda R.

    2012-01-01

    The concept of brain hemisphere dominance serves as the basis for many educational learning theories. The dominant brain hemisphere guides the learning process, but both hemispheres are necessary for true learning to take place. This treatise outlines and analyzes the dominance factor, a learning theory developed by Dr. Carla Hannaford, which…

  1. Hemispheric Asymmetries in the Activation and Monitoring of Memory Errors

    ERIC Educational Resources Information Center

    Giammattei, Jeannette; Arndt, Jason

    2012-01-01

    Previous research on the lateralization of memory errors suggests that the right hemisphere's tendency to produce more memory errors than the left hemisphere reflects hemispheric differences in semantic activation. However, all prior research that has examined the lateralization of memory errors has used self-paced recognition judgments. Because…

  2. Molecular phylogeny of the squeak beetles, a family with disjunct Palearctic-Australian range.

    PubMed

    Hawlitschek, Oliver; Hendrich, Lars; Balke, Michael

    2012-01-01

    Many higher groups of plants and animals show distributional patterns which have been shown or have at some point in time been suggested to be correlated with plate tectonics and the ancient supercontinents Laurasia and Gondwana. Here, we study the family of squeak beetles (Coleoptera: Adephaga: Hygrobiidae) and its enigmatic distribution pattern, with one species in the Western Palearctic, one in China and four in Australia. We present a molecular phylogeny including five of the six extant species, showing the monophyly of the Australian radiation. We use a molecular clock approach, which indicates that Hygrobiidae is an ancient group dating back to the breakup of Pangea and discuss the possibility of vicariance as explanation for its current distribution. PMID:22019931

  3. Testing the Language of German Cerebral Palsy Patients with Right Hemispheric Language Organization after Early Left Hemispheric Damage

    ERIC Educational Resources Information Center

    Schwilling, Eleonore; Krageloh-Mann, Ingeborg; Konietzko, Andreas; Winkler, Susanne; Lidzba, Karen

    2012-01-01

    Language functions are generally represented in the left cerebral hemisphere. After early (prenatally acquired or perinatally acquired) left hemispheric brain damage language functions may be salvaged by reorganization into the right hemisphere. This is different from brain lesions acquired in adulthood which normally lead to aphasia. Right…

  4. Hemispheric specialization for linguistic processing of sung speech.

    PubMed

    Yelle, Serena K; Grimshaw, Gina M

    2009-02-01

    The two hemispheres of the brain play complementary roles in song perception, with the left hemisphere specialized for processing the linguistic aspects of song and the right hemisphere specialized for the processing of melody. However, very little is known about how language and melody interact. The present study tested the hypothesis that right hemisphere linguistic processing would be facilitated by the presence of melody. In a dichotic listening paradigm, participants (8 men, 43 women) performed a linguistic task while listening to spoken or sung speech. Contrary to the hypothesis, left hemisphere specialization for linguistic processing was identical whether the sentences were spoken or sung. PMID:19425463

  5. Croll revisited: Why is the northern hemisphere warmer than the southern hemisphere?

    NASA Astrophysics Data System (ADS)

    Kang, Sarah M.; Seager, Richard; Frierson, Dargan M. W.; Liu, Xiaojuan

    2015-03-01

    The question of why, in the annual-mean, the northern hemisphere (NH) is warmer than the southern hemisphere (SH) is addressed, revisiting an 1870 paper by James Croll. We first show that ocean is warmer than land in general which, acting alone, would make the SH, with greater ocean fraction, warmer. Croll was aware of this and thought it was caused by greater specific humidity and greenhouse trapping over ocean than over land. However, for any given temperature, it is shown that greenhouse trapping is actually greater over land. Instead, oceans are warmer than land because of the smaller surface albedo. However, hemispheric differences in planetary albedo are negligible because the impact of differences in land-sea fraction are offset by the SH ocean and land reflecting more than their NH counterparts. In the absence of a role for albedo differences it is shown that, in agreement with Croll, northward cross-equatorial ocean heat transport (X-OHT) is critical for the warmer NH. This is examined in a simple box model based on the energy budget of each hemisphere. The hemispheric difference forced by X-OHT is enhanced by the positive water vapor-greenhouse feedback, and is partly compensated by the southward atmospheric energy transport. Due to uncertainties in the ocean data, a range of X-OHT is considered. A X-OHT of larger than 0.5 PW is needed to explain the warmer NH solely by X-OHT. For smaller X-OHT, a larger basic state greenhouse trapping in the NH, conceived as imposed by continental geometry, needs to be imposed. Numerical experiments with a GCM coupled to a slab ocean provide evidence that X-OHT is fundamentally important in determining the hemispheric differences in temperature. Therefore, despite some modifications to his theory, analysis of modern data confirms Croll's 140-year-old theory that the warmer NH is partly because of northward X-OHT.

  6. Inter-Hemispherical Currents for Realistic Model of Ionospheric Conductivity

    NASA Astrophysics Data System (ADS)

    Lyatsky, S.; Khazanov, G. V.

    2013-12-01

    We present results of modeling of the global 3-D ionosphere-magnetosphere current system including in addition to the R1 and R2 field-aligned currents also inter-hemispherical currents. The inter-hemispherical currents flow between Northern and Southern conjugate ionospheres in case of a North-South asymmetry in ionospheric conductivity in two hemispheres. These currents link together the ionospheric currents in two hemispheres, so the currents observed in one hemisphere can provide us with information about currents in the opposite hemisphere, which is especially important when their magnitude can not be obtained from direct observation (e.g., in Antarctica). In this study, we investigate the generation of the inter-hemispherical currents for several distributions of ionospheric conductivity in two hemispheres including a simplified model of ionospheric conductivity, which is important for better understanding of the expected distribution and magnitude of these currents, and a more realistic model of ionospheric conductivity, which is observed during magnetospheric substorms, when the geometry of the inter-hemispherical currents is more complicated. Simulation results show that the inter-hemispherical currents during substorms could play a very significant role, and neglecting these currents does not allow obtaining the correct picture of 3-D magnetosphere-ionosphere current system. These currents are an important part of 3-D field-aligned current system, and they are especially strong during summer-winter months, when they are comparable in magnitude with the R2 currents (about ~0.5 MA). Inter-hemispherical currents map. Left panel is related to Northern hemisphere, right panel to Southern. R1 and R2 currents are not shown; their locations are indicated by the red and blue dashed circles, respectively. The inter-hemispherical currents appear inside the auroral zone in the region of conductivity gradient. The currents in both hemispheres are equal in magnitude and

  7. Hubble Spots Northern Hemispheric Clouds on Uranus

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Using visible light, astronomers for the first time this century have detected clouds in the northern hemisphere of Uranus. The newest images, taken July 31 and Aug. 1, 1997 with NASA Hubble Space Telescope's Wide Field and Planetary Camera 2, show banded structure and multiple clouds. Using these images, Dr. Heidi Hammel (Massachusetts Institute of Technology) and colleagues Wes Lockwood (Lowell Observatory) and Kathy Rages (NASA Ames Research Center) plan to measure the wind speeds in the northern hemisphere for the first time.

    Uranus is sometimes called the 'sideways' planet, because its rotation axis tipped more than 90 degrees from the planet's orbit around the Sun. The 'year' on Uranus lasts 84 Earth years, which creates extremely long seasons - winter in the northern hemisphere has lasted for nearly 20 years. Uranus has also been called bland and boring, because no clouds have been detectable in ground-based images of the planet. Even to the cameras of the Voyager spacecraft in 1986, Uranus presented a nearly uniform blank disk, and discrete clouds were detectable only in the southern hemisphere. Voyager flew over the planet's cloud tops near the dead of northern winter (when the northern hemisphere was completely shrouded in darkness).

    Spring has finally come to the northern hemisphere of Uranus. The newest images, both the visible-wavelength ones described here and those taken a few days earlier with the Near Infrared and Multi-Object Spectrometer (NICMOS) by Erich Karkoschka (University of Arizona), show a planet with banded structure and detectable clouds.

    Two images are shown here. The 'aqua' image (on the left) is taken at 5,470 Angstroms, which is near the human eye's peak response to wavelength. Color has been added to the image to show what a person on a spacecraft near Uranus might see. Little structure is evident at this wavelength, though with image-processing techniques, a small cloud can be seen near the planet's northern limb

  8. HUBBLE SPOTS NORTHERN HEMISPHERIC CLOUDS ON URANUS

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Using visible light, astronomers for the first time this century have detected clouds in the northern hemisphere of Uranus. The newest images, taken July 31 and Aug. 1, 1997 with NASA Hubble Space Telescope's Wide Field and Planetary Camera 2, show banded structure and multiple clouds. Using these images, Dr. Heidi Hammel (Massachusetts Institute of Technology) and colleagues Wes Lockwood (Lowell Observatory) and Kathy Rages (NASA Ames Research Center) plan to measure the wind speeds in the northern hemisphere for the first time. Uranus is sometimes called the 'sideways' planet, because its rotation axis is tipped more than 90 degrees from the planet's orbit around the Sun. The 'year' on Uranus lasts 84 Earth years, which creates extremely long seasons - winter in the northern hemisphere has lasted for nearly 20 years. Uranus has also been called bland and boring, because no clouds have been detectable in ground-based images of the planet. Even to the cameras of the Voyager spacecraft in 1986, Uranus presented a nearly uniform blank disk, and discrete clouds were detectable only in the southern hemisphere. Voyager flew over the planet's cloud tops near the dead of northern winter (when the northern hemisphere was completely shrouded in darkness). Spring has finally come to the northern hemisphere of Uranus. The newest images, both the visible-wavelength ones described here and those taken a few days earlier with the Near Infrared and Multi-Object Spectrometer (NICMOS) by Erich Karkoschka (University of Arizona), show a planet with banded structure and detectable clouds. Two images are shown here. The 'aqua' image (on the left) is taken at 5,470 Angstroms, which is near the human eye's peak response to wavelength. Color has been added to the image to show what a person on a spacecraft near Uranus might see. Little structure is evident at this wavelength, though with image-processing techniques, a small cloud can be seen near the planet's northern limb (rightmost

  9. Hemispherical Capsule Implosions for Fast Ignition*

    NASA Astrophysics Data System (ADS)

    Hanson, D. L.; Vesey, R. A.; Sinars, D. B.; Adams, R. G.; Cuneo, M. E.; Porter, J. L.; Slutz, S. A.; Johnston, R. R.; Wenger, D. F.; Schroen, D. G.

    2003-10-01

    The fast ignitor approach to ICF ignition separates the fuel assembly and fast heating processes. After compressing the fuel with the main driver, the fuel is ignited using a focused electron or ion beam generated by a fast, ultra-high power laser pulse. This significantly relaxes the drive symmetry, energy, and shock timing requirements compared to hot spot ignition. A hemispherical capsule target is a fast ignitor geometry well-adapted to symmetric fuel compression by a single-ended z-pinch radiation drive. The hemispherical capsule implodes radially, constrained at its equator by a flat high-density surface (a special case of the spherical capsule "cone-focus" geometry). This glide plane is mounted on a hollow pedestal that provides a plasma-free, short-pulse laser path to the compressed fuel core region. In experiments on the Z accelerator at Sandia, we are studying implosions of 2.0-mm-diameter, 60-micron-thick hemispherical capsules in cylindrical secondary hohlraums heated to 90-100 eV from one end by a 120 TW wire-array z-pinch. Analysis of ZBL 6.7 keV point-projection backlighter images of pole-hot implosions in a tall secondary and 6.18 keV monochromatic crystal backlighter images of more symmetric implosions in a short secondary will be presented. We will also discuss progress on the development of a cryogenic liquid fuel target for this fast ignitor compression geometry. * Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  10. A revision of the Neotropical species of Bolitogyrus Chevrolat, a geographically disjunct lineage of Staphylinini (Coleoptera, Staphylinidae)

    PubMed Central

    Brunke, Adam J.; Solodovnikov, Alexey

    2014-01-01

    Abstract The Neotropical species of the rarely collected genus Bolitogyrus (Coleoptera: Staphylinidae: Staphylininae: Staphylinini) are revised. The genus exhibits an uncommon, disjunct distribution between the Neotropical and Oriental Regions and is of unknown phylogenetic position within Staphylinini. Morphological evolution remarkable for Staphylinini was discovered within Bolitogyrus, including sexually dimorphic modifications of the pronotum that may be involved in male competition for females. rSEM interactive animations were used to establish morphological species boundaries between two highly variable species and are provided to illustrate diagnostic characters of the genitalia in unconventional views. The genus is redescribed based on the world fauna and twenty-eight Neotropical species are considered valid. Of these, nineteen are described as new to science: Bolitogyrus ashei sp. n.; B. apicofasciatus sp. n.; B. brevistellus sp. n.; B. bufo sp. n.; B. cheungi sp. n.; B. cornutus sp. n.; B. divisus sp. n.; B. falini sp. n.; B. gracilis sp. n.; B. inexspectatus sp. n.; B. longistellus sp. n.; B. marquezi sp. n.; B. newtoni sp. n.; B. pseudotortifolius sp. n.; B. pulchrus sp. n.; B. silex sp. n.; B. thomasi sp. n.; B. tortifolius sp. n.; and B. viridescens sp. n. Bolitogyrus sallei (Kraatz), stat. r. is removed from synonymy with B. buphthalmus (Erichson) and the following new synonyms are proposed: Cyrtothorax cyanescens Sharp, 1884, syn. n. = Quedius buphthalmus Erichson, 1840; C. nevermanni Scheerpeltz, 1974, syn. n. = C. costaricensis Wendeler, 1927. A summary of all available bionomic and distributional data, as well as an illustrated identification key to and diagnoses of all Neotropical species are provided. PMID:25061393

  11. Thousands of RAD-seq Loci Fully Resolve the Phylogeny of the Highly Disjunct Arctic-Alpine Genus Diapensia (Diapensiaceae)

    PubMed Central

    Hou, Yan; Nowak, Michael D.; Mirré, Virginia; Bjorå, Charlotte S.; Brochmann, Christian; Popp, Magnus

    2015-01-01

    Restriction-site associated DNA sequencing (RAD-seq) has recently become an important method to generate genome-wide molecular data for species delimitation, phylogeography, and population genetic studies. However, very few empirical studies have so far tested its applicability in phylogenetic reconstruction. The alpine-arctic genus Diapensia was selected to study the origin of the disjunction between the Arctic and the Himalayan-Hengduan Mountains (HHM). However, a previous phylogenetic analysis based on one nuclear and four plastid DNA regions failed to resolve the oldest divergences in Diapensia as well as the relationship between the two HHM species. Here we reconstruct a fully resolved phylogeny of Diapensia and address the conflict between the currently accepted taxonomy and the gene trees in the HHM species using RAD-seq. Based on a data set containing 2,650 loci selected to maximize the number of parsimony informative sites and allowing for a high level of missing data (51%), the phylogeny of Diapensia was fully resolved and each of the four species was reciprocally monophyletic. Whereas the arctic D. lapponica was inferred as sister to the HHM clade in the previous study, the RAD-seq data resolved the two arctic species as sisters to the HHM clade. Similar relationships were inferred from a differently filtered data set with far fewer loci (114) and less missing data (21%), but with lower support and with one of the two HHM species as non-monophyletic. Bayesian concordance analysis and Patterson’s D-statistic tests suggested that admixture has occurred between the two HHM species. PMID:26448557

  12. Phylogeny and biogeography of the eastern Asian-North American disjunct wild-rice genus (Zizania L., Poaceae).

    PubMed

    Xu, Xinwei; Walters, Christina; Antolin, Michael F; Alexander, Mara L; Lutz, Sue; Ge, Song; Wen, Jun

    2010-06-01

    The wild-rice genus Zizania includes four species disjunctly distributed in eastern Asia and North America, with three species (Z. aquatica, Z. palustris, and Z. texana) in North America and one (Z. latifolia) in eastern Asia. The phylogeny of Zizania was constructed using sequences of seven DNA fragments (atpB-rbcL, matK, rps16, trnL-F, trnH-psbA, nad1, and Adh1a) from chloroplast, mitochondrial, and nuclear genomes. Zizania is shown to be monophyletic with the North American species forming a clade and the eastern Asian Z. latifolia sister to the North American clade. The divergence between the eastern Asian Z. latifolia and the North American clade was dated to be 3.74 (95% HPD: 1.04-7.23) million years ago (mya) using the Bayesian dating method with the combined atpB-rbcL, matK, rps16, trnL-F, and nad1 data. Biogeographic analyses using a likelihood method suggest the North American origin of Zizania and its migration into eastern Asia via the Bering land bridge. Among the three North American species, the organellar data and the haplotype network of the nuclear Adh1a gene show a close relationship between Z. palustris and the narrowly distributed endangered species Z. texana. Bayesian dating estimated the divergence of North American Zizania to be 0.71 (95% HPD: 0.12-1.54) mya in the Pleistocene. The non-monophyly of Z. palustris and Z. aquatica in the organellar and nuclear data is most likely caused by incomplete lineage sorting, yet low-frequency unidirectional introgression of Z. palustris into Z. aquatica is present in the nuclear data as well. PMID:19944174

  13. Reproductive biology of Syzygiella rubricaulis (Nees) Steph. (Adelanthaceae, Marchantiophyta), a liverwort disjunctly distributed in high-altitude Neotropical mountains.

    PubMed

    Maciel-Silva, A S; Gaspar, E P; da Conceição, F P; Dias Dos Santos, N; Pinheiro da Costa, D

    2016-07-01

    Syzygiella rubricaulis is a dioecious leafy liverwort disjunctly distributed and restricted to high-altitude mountains in the Neotropics and the Azores. This study is part of a larger project examining the phylogeography of S. rubricaulis in the Neotropics, and our main goals were to understand its reproductive biology, where sex expression occurs, if vegetative propagules are frequently found, how the sexes are distributed in populations, how frequently sporophytes are formed and what environmental conditions influence sexual expression. S. rubricaulis patches are mostly female, but all patches also contain non sex-expressing shoots. Out of 42 patches examined, 29 (69%) were sex-expressing: 25 were unisexual (21 female and four male) and four of mixed sex (two male-biased and two unbiased). At shoot level, out of 4200 shoots 18% were female and 7% male; among sex-expressing shoots, 73% were female, representing a sex ratio of 0.8 (female-biased). We encountered a total of 33 sporophytes in six patches (in Brazil, Venezuela and Ecuador). Leaf regenerants were found in one patch in Mexico. Low rates of sporophytes were likely related to low frequencies of male shoots and large distances between the sexes. As 25% of S. rubricaulis shoots expressed sex (occasionally producing sporophytes), we suggest that short-distance (and rarely long-distance) spore dispersal events occur in mountainous areas on a short-term basis. On a long-term basis, however, these events likely contribute to dynamic exchanges among populations in the Neotropics. PMID:26929143

  14. Disjunct distributions of freshwater snails testify to a central role of the Congo system in shaping biogeographical patterns in Africa

    PubMed Central

    2014-01-01

    Background The formation of the East African Rift System has decisively influenced the distribution and evolution of tropical Africa’s biota by altering climate conditions, by creating basins for large long-lived lakes, and by affecting the catchment and drainage directions of river systems. However, it remains unclear how rifting affected the biogeographical patterns of freshwater biota through time on a continental scale, which is further complicated by the scarcity of molecular data from the largest African river system, the Congo. Results We study these biogeographical patterns using a fossil-calibrated multi-locus phylogeny of the gastropod family Viviparidae. This group allows reconstructing drainage patterns exceptionally well because it disperses very poorly in the absence of existing freshwater connections. Our phylogeny covers localities from major drainage basins of tropical Africa and reveals highly disjunct sister-group relationships between (a) the endemic viviparids of Lake Malawi and populations from the Middle Congo as well as between (b) the Victoria region and the Okavango/Upper Zambezi area. Conclusions The current study testifies to repeated disruptions of the distribution of the Viviparidae during the formation of the East African Rift System, and to a central role of the Congo River system for the distribution of the continent’s freshwater fauna during the late Cenozoic. By integrating our results with previous findings on palaeohydrographical connections, we provide a spatially and temporarily explicit model of historical freshwater biogeography in tropical Africa. Finally, we review similarities and differences in patterns of vertebrate and invertebrate dispersal. Amongst others we argue that the closest relatives of present day viviparids in Lake Malawi are living in the Middle Congo River, thus shedding new light on the origin of the endemic fauna of this rift lake. PMID:24597925

  15. Circular single domains in hemispherical Permalloy nanoclusters

    SciTech Connect

    Araujo, Clodoaldo I. L de Fonseca, Jakson M.; Sinnecker, João P.; Delatorre, Rafael G.; Garcia, Nicolas; Pasa, André A.

    2014-11-14

    We have studied ferromagnetic Permalloy clusters obtained by electrodeposition on n-type silicon. Magnetization measurements reveal hysteresis loops almost independent on temperature and very similar in shape to those obtained in nanodisks with diameter bigger than 150 nm. The spin configuration for the ground state, obtained by micromagnetic simulation, shows topological vortices with random chirality and polarization. This behavior in the small diameter clusters (∼80 nm) is attributed to the Dzyaloshinskii-Moriya interaction that arises in its hemispherical geometries. This magnetization behavior can be utilized to explain the magnetoresistance measured with magnetic field in plane and out of sample plane.

  16. Hemispheric asymmetries in reading Korean: task matters.

    PubMed

    Vaid, J; Park, K

    1997-06-01

    Native Korean readers were studied in a visual half-field paradigm. Subjects were to make speeded judgments on Hangul (syllabic) and Hanzza (logographic) scripts based on phonetic or visual properties of the stimuli. A task by visual field interaction was obtained indicating that, for both scripts, responses on the phonetic task were faster in the right visual field, whereas no visual field differences were found on the visual task. Script type did not interact with visual field. The results support a task-based account of hemispheric differences in verbal processing. PMID:9184098

  17. The genus Platychara from the Western Hemisphere

    USGS Publications Warehouse

    Peck, R.E.; Forester, R.M.

    1979-01-01

    The systematics of four species belonging to the genus Platychara (Charophyta) from the Western Hemisphere is discussed. Three of the species, as defined herein, occur in Cretaceous and Paleocene rocks from Mexico through South America. The type species, P. compressa (Peck and Reker) Grambast, also of Cretaceous and Paleocene age, is herein restricted to deposits north of Mexico. These latter restrictions geographically separate P. compressa and P. perlata as presently defined but the relationship between these two species is still uncertain. A new species, P. grambastii, is proposed for specimens from Maestrichtian sediments in Jamaica. ?? 1979.

  18. Tracing Fukushima Radionuclides in the Northern Hemisphere -An Overview

    NASA Astrophysics Data System (ADS)

    Thakur, Punam; Ballard, Sally; Nelson, Roger

    2013-04-01

    A massive 9.0 earthquake and ensuing tsunami struck the northern coast of the Honshu-island, Japan on March 11, 2011 and severely damaged the electric system of the Fukushima- Daiichi Nuclear Power Plant (NPP). The structural damage to the plant disabled the reactor's cooling systems. Subsequent fires, a hydrogen explosion and possible partial core meltdowns released radioactive fission products into the atmosphere. The atmospheric release from the crippled Fukushima NPP started on March 12, 2011 with a maximum release phase from March 14 to 17. The radioactivity released was dominated by volatile fission products including isotopes of the noble gases xenon (Xe-133) and krypton (Kr-85); iodine (I-131,I-132); cesium (Cs-134,Cs-136,Cs-137); and tellurium (Te-132). The non-volatile radionuclides such as isotopes of strontium and plutonium are believed to have remained largely inside the reactor, although there is evidence of plutonium release into the environment. Global air monitoring across the northern hemisphere was increased following the first reports of atmospheric releases. According to the source term, declared by the Nuclear and Industrial Safety Agency (NISA) of Japan), approximately 160 PBq (1 PBq (Peta Becquerel = 10^15 Bq)) of I-131 and 15 PBq of Cs-137 (or 770 PBq "iodine-131 equivalent"), were released into the atmosphere. The 770 PBq figure is about 15% of the Chernobyl release of 5200 PBq of "iodine-131 equivalent". For the assessment of contamination after the accident and to track the transport time of the contaminated air mass released from the Fukushima NPP across the globe, several model calculations were performed by various research groups. All model calculations suggested long-range transport of radionuclides from the damaged Fukushima NPP towards the North American Continent to Europe and to Central Asia. As a result, an elevated level of Fukushima radionuclides were detected in air, rain, milk, and vegetation samples across the northern

  19. Hemispheric specialization in dogs for processing different acoustic stimuli.

    PubMed

    Siniscalchi, Marcello; Quaranta, Angelo; Rogers, Lesley J

    2008-01-01

    Considerable experimental evidence shows that functional cerebral asymmetries are widespread in animals. Activity of the right cerebral hemisphere has been associated with responses to novel stimuli and the expression of intense emotions, such as aggression, escape behaviour and fear. The left hemisphere uses learned patterns and responds to familiar stimuli. Although such lateralization has been studied mainly for visual responses, there is evidence in primates that auditory perception is lateralized and that vocal communication depends on differential processing by the hemispheres. The aim of the present work was to investigate whether dogs use different hemispheres to process different acoustic stimuli by presenting them with playbacks of a thunderstorm and their species-typical vocalizations. The results revealed that dogs usually process their species-typical vocalizations using the left hemisphere and the thunderstorm sounds using the right hemisphere. Nevertheless, conspecific vocalizations are not always processed by the left hemisphere, since the right hemisphere is used for processing vocalizations when they elicit intense emotion, including fear. These findings suggest that the specialisation of the left hemisphere for intraspecific communication is more ancient that previously thought, and so is specialisation of the right hemisphere for intense emotions. PMID:18843371

  20. Inter-hemispheric temperature variability over the past millennium

    NASA Astrophysics Data System (ADS)

    Neukom, Raphael; Gergis, Joëlle; Karoly, David J.; Wanner, Heinz; Curran, Mark; Elbert, Julie; González-Rouco, Fidel; Linsley, Braddock K.; Moy, Andrew D.; Mundo, Ignacio; Raible, Christoph C.; Steig, Eric J.; van Ommen, Tas; Vance, Tessa; Villalba, Ricardo; Zinke, Jens; Frank, David

    2014-05-01

    The Earth's climate system is driven by a complex interplay of internal chaotic dynamics and natural and anthropogenic external forcing. Recent instrumental data have shown a remarkable degree of asynchronicity between Northern Hemisphere and Southern Hemisphere temperature fluctuations, thereby questioning the relative importance of internal versus external drivers of past as well as future climate variability. However, large-scale temperature reconstructions for the past millennium have focused on the Northern Hemisphere, limiting empirical assessments of inter-hemispheric variability on multi-decadal to centennial timescales. Here, we introduce a new millennial ensemble reconstruction of annually resolved temperature variations for the Southern Hemisphere based on an unprecedented network of terrestrial and oceanic palaeoclimate proxy records. In conjunction with an independent Northern Hemisphere temperature reconstruction ensemble, this record reveals an extended cold period (1594-1677) in both hemispheres but no globally coherent warm phase during the pre-industrial (1000-1850) era. The current (post-1974) warm phase is the only period of the past millennium where both hemispheres are likely to have experienced contemporaneous warm extremes. Our analysis of inter-hemispheric temperature variability in an ensemble of climate model simulations for the past millennium suggests that models tend to overemphasize Northern Hemisphere-Southern Hemisphere synchronicity by underestimating the role of internal ocean-atmosphere dynamics, particularly in the ocean-dominated Southern Hemisphere. Our results imply that climate system predictability on decadal to century timescales may be lower than expected based on assessments of external climate forcing and Northern Hemisphere temperature variations alone.

  1. Hemispheric specialization for handwriting in right handers.

    PubMed

    Mack, L; Gonzalez Rothi, L J; Heilman, K M

    1993-01-01

    Hand preference may be related to either lateralized language, movement representations, or both. Anatomic and behavioral studies have revealed that whereas each hemisphere has motor control of the contralateral distal and proximal limb movements, this same hemisphere's control over the ipsilateral limb is limited to proximal movements. This differential proximal-versus-distal organization may have functional implications such that when right handers write with their left hand they must be use more proximal musculature than when they write with their right hand. If hand preference is related to lateralized movement representations, right handers may also use more proximal than distal movements when drawing with their left than with their right hand. If one uses distal musculature to write or draw, the elbow travels through space less than if one uses proximal musculature. We studied 12 right handers by having them write and draw with their right and left hands and measured the spatial amplitude of their elbow movements. We found that when writing or drawing, right handers moved their left elbow more than their right. These results suggest that it is the lateralized movement representations that may be primarily responsible for writing hand preference. PMID:8424864

  2. Flow past 2-D Hemispherical Rigid Canopies

    NASA Astrophysics Data System (ADS)

    Carnasciali, Maria-Isabel

    2013-11-01

    The flow past a 2-dimensional rigid hemispherical shape is investigated using PIV. Flow field measurements and images were generated with the use of a Thermoflow® apparatus. Results of this study are compared to prior work (APS DFD 2012 Session E9.00003) which employed CFD to investigate the flow in the near wake of hemispherical parachutes. The various sized gaps/open areas were positioned at distinct locations. The work presented here is part of a larger research project to investigate flow fields in deceleration devices and parachutes. Understanding the pitch-stability of parachutes is essential for accurate design and implementation of these deceleration devices but they present a difficult system to analyze. The flexibility of the parachute fabric results in large variations in the parachute geometry leading to complex fluid-structure interactions. Such flow, combined with flow through gaps and open areas, has been postulated to shed alternating vortices causing pitching/oscillations of the canopy. The results presented provide some insight into which geometric features affect vortex shedding and may enable the redesign of the baseline parachute to minimize instabilities.

  3. Inferring the thermal-infrared hemispheric emission from a sparsely-vegetated surface by directional measurements

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Susskind, J.; Brakke, T.; Kimes, D.; Pielke, R.; Lee, T. J.

    1995-01-01

    The thermal-infrared (longwave) emission from a vegetated terrain is generally anisotropic, i.e., the emission temperature varies with the view direction. If a directional measurement of temperature is considered to be equal to the effective temperature of the hemispheric emission, then the estimate of the latter can be significantly in error. The view-direction (zenith angle theta(sub eq) at which the emission equivalence does hold is determined in our modeling study. In a two-temperature field-of-view (soil and plants), theta(sub eq) falls in a narrow range depending on plant density and canopy architecture. Theta(sub eq) does not depend on soil and (uniform) plant temperatures nor on their ratio, even though the pattern of emission vs. the view direction depends crucially on this ratio. For a sparse canopy represented as thin, vertical cylindrical stalks (or vertical blades uniformly distributed in azimuth) with horizontal facets, theta(sub eq) ranges from 48 to 53 deg depending on the optical density of the vertical elements alone. When plant elements are modeled as small spheres, theta(sub eq) lies between 53 to 57 deg (for the same values of the canopy optical density). Only for horizontal leaves (a truly planophile canopy) is the temperature measured from any direction equal to the temperature of the hemispheric emission. When the emission temperature changes with optical depth within the canopy at a specified rate, theta(sub eq) depends to some extent on that rate. For practically any sparsely vegetated surface, a directional measurement at the zenith angle of 50 deg offers an appropriate evaluation of the hemispheric emission, since the error in the estimate will, at most, only slightly exceed 1% (around 4 W/sq m). Estimates of the hemispheric emission through a nadir measurement, on the other hand, can be in error in some cases by about 10%, i.e., on the order of 40 W/sq m.

  4. Ancient vicariance and climate-driven extinction continental-wide disjunctions in Africa: the case of the Rand Flora genus Canarina (Campanulaceae).

    PubMed

    Mairal, M; Pokorny, L; Aldasoro, J J; Alarcón, M; Sanmartín, I

    2015-03-01

    Transoceanic distributions have attracted the interest of scientists for centuries. Less attention has been paid to the evolutionary origins of 'continent-wide' disjunctions, in which related taxa are distributed across isolated regions within the same continent. A prime example is the 'Rand Flora' pattern, which shows sister taxa disjunctly distributed in the continental margins of Africa. Here, we explore the evolutionary origins of this pattern using the genus Canarina, with three species: C. canariensis, associated with the Canarian laurisilva, and C. eminii and C. abyssinica, endemic to the Afromontane region in East Africa, as case study. We infer phylogenetic relationships, divergence times and the history of migration events within Canarina using Bayesian inference on a large sample of chloroplast and nuclear sequences. Ecological niche modelling was employed to infer the climatic niche of Canarina through time. Dating was performed with a novel nested approach to solve the problem of using deep time calibration points within a molecular dataset comprising both above-species and population-level sampling. Results show C. abyssinica as sister to a clade formed by disjunct C. eminii and C. canariensis. Miocene divergences were inferred among species, whereas infraspecific divergences fell within the Pleistocene-Holocene periods. Although C. eminii and C. canariensis showed a strong genetic geographic structure, among-population divergences were older in the former than in the latter. Our results suggest that Canarina originated in East Africa and later migrated across North Africa, with vicariance and aridification-driven extinction explaining the 7000 km/7 million year divergence between the Canarian and East African endemics. PMID:25688489

  5. Hemisphere asymmetry in parasympathetic control of the heart.

    PubMed

    Wittling, W; Block, A; Genzel, S; Schweiger, E

    1998-05-01

    Hemisphere asymmetry in the control of parasympathetic outflow to the sino-atrial node of the heart was studied in healthy human subjects using lateralized film presentation for selective sensory stimulation of the hemispheres and power spectral analysis of heart rate variability as a measure of vagal tone. There was a clear and consistent left hemisphere predominance in the control of parasympathetic modulation of cardiac activity which cannot be attributed to differences in emotional processing. Supplementing previous findings of our research group, the present study indicates that control of autonomic cardiac activity at the level of the cerebral cortex seems to be characterized by a division of responsibility between both hemispheres, sympathetic activity being mainly controlled by the right hemisphere and parasympathetic activity being under the left hemisphere's main control. PMID:9699952

  6. Disjunct distribution of highly diverged mitochondrial lineage clade and population subdivision in a marine bivalve with pelagic larval dispersal.

    PubMed

    Luttikhuizen, P C; Drent, J; Baker, A J

    2003-08-01

    Mitochondrial DNA sequence data for 295 individuals of the marine bivalve Macoma balthica (L.) were collected from 10 sites across the European distribution, and from Alaska. The data were used to infer population subdivision history and estimate current levels of gene flow. Inferred historical biogeography was expected to be congruent with colonization of the Atlantic Ocean from the Pacific Ocean after the opening of the Bering Strait 3.5 Ma. In addition, the last glacial maximum, about 18000 years ago, was expected to have been responsible for most of the present-day distribution of molecular variation within Europe, because the area must have been recolonized after confinement to France and the south of the British Isles during the last glacial maximum. Current gene flow was hypothesized to be high, because the larvae of M. balthica spend 2-5 weeks drifting in the water column. The geographical distribution of one highly diverged haplotype clade was found to be disjunct and was encountered exclusively in samples from the Baltic Sea and Alaska. A molecular clock calibration for marine bivalve cytochrome-c-oxidase I dates this clade as having split off from the other haplotypes 9.8-39 Ma. Multiple colonizations of the Atlantic Ocean from the Pacific by M. balthica may explain the strong differences found between Baltic Sea and other European populations of this species. The sympatric occurrence of the highly diverged mitochondrial lineages in western parts of the Baltic Sea points to secondary admixture. With the use of coalescent analysis, population divergence times for French vs. other non-Baltic European populations ('Atlantic population assemblage') were estimated at a minimum of about 110000 years ago, well before the last glacial maximum 18000 years ago. Signatures of population divergence of M. balthica that appear to have originated during the Pleistocene have thus survived the last glacial maximum. Some of the populations within the Atlantic assemblage

  7. Paleoceanography. Antarctic role in Northern Hemisphere glaciation.

    PubMed

    Woodard, Stella C; Rosenthal, Yair; Miller, Kenneth G; Wright, James D; Chiu, Beverly K; Lawrence, Kira T

    2014-11-14

    Earth's climate underwent a major transition from the warmth of the late Pliocene, when global surface temperatures were ~2° to 3°C higher than today, to extensive Northern Hemisphere glaciation (NHG) ~2.73 million years ago (Ma). We show that North Pacific deep waters were substantially colder (4°C) and probably fresher than the North Atlantic Deep Water before the intensification of NHG. At ~2.73 Ma, the Atlantic-Pacific temperature gradient was reduced to <1°C, suggesting the initiation of stronger heat transfer from the North Atlantic to the deep Pacific. We posit that increased glaciation of Antarctica, deduced from the 21 ± 10-meter sea-level fall from 3.15 to 2.75 Ma, and the development of a strong polar halocline fundamentally altered deep ocean circulation, which enhanced interhemispheric heat and salt transport, thereby contributing to NHG. PMID:25342658

  8. Voyager 1 Jupiter Southern Hemisphere Movie

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This movie shows a portion of Jupiter in the southern hemisphere over 17Jupiter days. Above the white belt, notice the series of atmospheric vortices headed west. Even these early approach frames show wild dynamics in the roiling environment south of the white belt. Notice the small tumbling white cloud near the center.

    As Voyager 1 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 17 images taken once every Jupiter rotation period (about 10 hours). These images were acquired in the Blue filter around Feb. 1, 1979. The spacecraft was about 37 million kilometers from Jupiter at that time.

    This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

  9. Dynamics of charged hemispherical soap bubbles

    NASA Astrophysics Data System (ADS)

    Hilton, J. E.; van der Net, A.

    2009-04-01

    Raising the potential of a charged hemispherical soap bubble over a critical limit causes deformation of the bubble into a cone and ejection of a charged liquid jet. This is followed by a mode which has not previously been observed in bubbles, in which a long cylindrical liquid film column is created and collapses due to a Rayleigh-Plateau instability creating child bubbles. We show that the formation of the column and subsequent creation of child bubbles is due to a drop in potential caused by the ejection of charge from the system via the jet. Similar dynamics may occur in microscopic charged liquid droplets (electrospray processes), causing the creation of daughter droplets and long liquid spindles.

  10. A simple EHF hemispheric coverage antenna

    NASA Astrophysics Data System (ADS)

    Lee, J. C.

    1994-08-01

    A circulary polarized, axially symmetric, wide-beam radiator is required in many applications, including TT&C for UAV's and satellites. This report discusses some existing wide-beam antenna designs including divergent lenses and reflectors and introduces a new antenna design. Using a simple dielectric ring in conjunction with a dielectric loaded circular waveguide opening, a near ideal, axially symmetric, hemispheric coverage antenna with circular polarization of good axial ratio and wide-band impedance match is realized. Mechanically, the antenna is small, lightweight, and low cost. The dielectric used is the common Rexolite. Since no lossy materials or resonant scatterers are used, the antenna performance is inherently broadband and low loss. A K sub a-band prototype as well as compact designs for both Q- and K-bands are described.

  11. Interpretation of recent Southern Hemisphere climate change.

    PubMed

    Thompson, David W J; Solomon, Susan

    2002-05-01

    Climate variability in the high-latitude Southern Hemisphere (SH) is dominated by the SH annular mode, a large-scale pattern of variability characterized by fluctuations in the strength of the circumpolar vortex. We present evidence that recent trends in the SH tropospheric circulation can be interpreted as a bias toward the high-index polarity of this pattern, with stronger westerly flow encircling the polar cap. It is argued that the largest and most significant tropospheric trends can be traced to recent trends in the lower stratospheric polar vortex, which are due largely to photochemical ozone losses. During the summer-fall season, the trend toward stronger circumpolar flow has contributed substantially to the observed warming over the Antarctic Peninsula and Patagonia and to the cooling over eastern Antarctica and the Antarctic plateau. PMID:11988571

  12. The Right Hemisphere in Esthetic Perception

    PubMed Central

    Bromberger, Bianca; Sternschein, Rebecca; Widick, Page; Smith, William; Chatterjee, Anjan

    2011-01-01

    Little about the neuropsychology of art perception and evaluation is known. Most neuropsychological approaches to art have focused on art production and have been anecdotal and qualitative. The field is in desperate need of quantitative methods if it is to advance. Here, we combine a quantitative approach to the assessment of art with modern voxel-lesion-symptom-mapping methods to determine brain–behavior relationships in art perception. We hypothesized that perception of different attributes of art are likely to be disrupted by damage to different regions of the brain. Twenty participants with right hemisphere damage were given the Assessment of Art Attributes, which is designed to quantify judgments of descriptive attributes of visual art. Each participant rated 24 paintings on 6 conceptual attributes (depictive accuracy, abstractness, emotion, symbolism, realism, and animacy) and 6 perceptual attributes (depth, color temperature, color saturation, balance, stroke, and simplicity) and their interest in and preference for these paintings. Deviation scores were obtained for each brain-damaged participant for each attribute based on correlations with group average ratings from 30 age-matched healthy participants. Right hemisphere damage affected participants’ judgments of abstractness, accuracy, and stroke quality. Damage to areas within different parts of the frontal parietal and lateral temporal cortices produced deviation in judgments in four of six conceptual attributes (abstractness, symbolism, realism, and animacy). Of the formal attributes, only depth was affected by inferior prefrontal damage. No areas of brain damage were associated with deviations in interestingness or preference judgments. The perception of conceptual and formal attributes in artwork may in part dissociate from each other and from evaluative judgments. More generally, this approach demonstrates the feasibility of quantitative approaches to the neuropsychology of art. PMID:22016728

  13. Hemispherical Resonator Gyro: an IRU for Cassini

    NASA Astrophysics Data System (ADS)

    Litty, Edward C.; Gresham, Lennor L.; Toole, Patrick A.; Beisecker, Debra A.

    1996-10-01

    The JPL Inertial Reference Unit (IRU) is the single most sophisticated assembly on the Cassini spacecraft. At the core of the IRU is the state-of-the-art, Litton Hemispherical Resonator Gyro (HRG). Launched in October 1997, Cassini's trajectory utilizes gravity assist maneuvers around Venus (two), Earth, and Jupiter over a seven year period, arriving at Saturn in June 2004. Its tour of the Saturnian system will last an additional four years. Although the Stellar Reference Unit (SRU) provides the ultimate reference for the spacecraft Attitude and Articulation Control System (AACS) and can be used to control the spacecraft under benign conditions, the Cassini IRU is essential during maneuvers and fault recovery operations, and for precision attitude stabilization during science data acquisition. Therefore, IRU reliability over the long Cassini mission is a critical concern. Following an extensive evaluation of possible alternatives, the Hemispherical Resonator Gyro (HRG) based IRU developed by Litton Guidance and Control Systems, was chosen for the Cassini mission. The HRG is an attitude rate sensor that has no physical wear-out mechanisms. Based on a principle first described by G. H. Bryan (1890) in his paper, 'On Beats in the Vibrations of a Revolving Cylinder or Bell', the HRG is created by vibrating a quartz resonator. This paper discusses the theory and modifications required to the design of the standard Space Inertial Reference Unit to adapt it to meet the requirements of the Cassini mission and the AACS interface. The Cassini mission is the first use of an IRU for a deep space planetary mission that does not use a spun-mass sensor.

  14. The right hemisphere in esthetic perception.

    PubMed

    Bromberger, Bianca; Sternschein, Rebecca; Widick, Page; Smith, William; Chatterjee, Anjan

    2011-01-01

    Little about the neuropsychology of art perception and evaluation is known. Most neuropsychological approaches to art have focused on art production and have been anecdotal and qualitative. The field is in desperate need of quantitative methods if it is to advance. Here, we combine a quantitative approach to the assessment of art with modern voxel-lesion-symptom-mapping methods to determine brain-behavior relationships in art perception. We hypothesized that perception of different attributes of art are likely to be disrupted by damage to different regions of the brain. Twenty participants with right hemisphere damage were given the Assessment of Art Attributes, which is designed to quantify judgments of descriptive attributes of visual art. Each participant rated 24 paintings on 6 conceptual attributes (depictive accuracy, abstractness, emotion, symbolism, realism, and animacy) and 6 perceptual attributes (depth, color temperature, color saturation, balance, stroke, and simplicity) and their interest in and preference for these paintings. Deviation scores were obtained for each brain-damaged participant for each attribute based on correlations with group average ratings from 30 age-matched healthy participants. Right hemisphere damage affected participants' judgments of abstractness, accuracy, and stroke quality. Damage to areas within different parts of the frontal parietal and lateral temporal cortices produced deviation in judgments in four of six conceptual attributes (abstractness, symbolism, realism, and animacy). Of the formal attributes, only depth was affected by inferior prefrontal damage. No areas of brain damage were associated with deviations in interestingness or preference judgments. The perception of conceptual and formal attributes in artwork may in part dissociate from each other and from evaluative judgments. More generally, this approach demonstrates the feasibility of quantitative approaches to the neuropsychology of art. PMID:22016728

  15. Hemispheric asymmetries of the Venus plasma environment

    NASA Astrophysics Data System (ADS)

    Jarvinen, R.; Kallio, E.; Dyadechkin, S.

    2013-07-01

    We study the Venus-solar wind interaction and the hemispheric asymmetries of the Venus plasma environment in the global HYB-Venus hybrid simulation. We concentrate especially on the role of the flow-aligned interplanetary magnetic field (IMF) component (i.e., the Parker spiral angle or the IMF cone angle) and analyze the dawn-dusk and Esw asymmetries between four magnetic quadrants around Venus. Using the simulation model, we study two upstream condition cases in detail: the perpendicular IMF to the solar wind flow case and the nominal Parker spiral case (dominant flow-aligned IMF component). Several differences and similarities were found in these two simulation runs. Common features of the Venus plasma environment between the two cases include asymmetric magnetic barrier and tail lobes and asymmetric planetary ion escape in the direction of the solar wind convection electric field. Further, protons of planetary origin and of solar wind origin were found to follow similar velocity patterns in the Venus plasma wake in both cases. The differences when the IMF flow-aligned component is dominating compared to the perpendicular IMF case, the so-called (magnetic) dawn-dusk asymmetries, include the parallel bow shock and the foreshock region, the asymmetric magnetic barrier, the asymmetric tail current system, and the asymmetric central tail current sheet. Further, the escaping planetary H+ and O+ ion fluxes are concentrated more on the hemisphere of the parallel bow shock. When interpreting in situ plasma and magnetic observations from Venus, the features of at least these two basic IMF configurations should be considered.

  16. Chiasmatic and achiasmatic inverted meiosis of plants with holocentric chromosomes

    PubMed Central

    Cabral, Gabriela; Marques, André; Schubert, Veit; Pedrosa-Harand, Andrea; Schlögelhofer, Peter

    2014-01-01

    Meiosis is a specialized cell division in sexually reproducing organisms before gamete formation. Following DNA replication, the canonical sequence in species with monocentric chromosomes is characterized by reductional segregation of homologous chromosomes during the first and equational segregation of sister chromatids during the second meiotic division. Species with holocentric chromosomes employ specific adaptations to ensure regular disjunction during meiosis. Here we present the analysis of two closely related plant species with holocentric chromosomes that display an inversion of the canonical meiotic sequence, with the equational division preceding the reductional. In-depth analysis of the meiotic divisions of Rhynchospora pubera and R. tenuis reveals that during meiosis I sister chromatids are bi-oriented, display amphitelic attachment to the spindle and are subsequently separated. During prophase II, chromatids are connected by thin chromatin threads that appear instrumental for the regular disjunction of homologous non-sister chromatids in meiosis II. PMID:25295686

  17. New records and distribution modeling of Gryne orensis (Sørensen) (Opiliones: Cosmetidae) support the Mesopotamian-Yungas disjunction in subtropical Argentina.

    PubMed

    Acosta, Luis E; Vergara, Julia

    2013-01-01

    The presence of Gryne orensis (Sørensen) (Opiliones: Cosmetidae) in a Yungas locality (northwestern Argentina) is reported for the first time, providing new evidence for the Mesopotamian-Yungas disjunct pattern. Combining a total of 19 new Mesopotamian records with previous, reliable citations from the literature, a dataset of 45 points was used to model the potential distribution of the species, using the presence-only methods BIOCLIM and MAXENT. Models supported the existence of a distributional gap across the Semiarid Chaco. The imprecise literature record from "El Impenetrable", province of Chaco, is assigned to three tentative locations to evaluate if models are affected by their inclusion; in all cases, the disjunction was maintained. It was thereby estimated that the actual record might have originated in a site closer to the Humid Chaco and/or associated to streams. This paper also provides a statement of the bioclimatic profile and identification of major environmental constraints that define the range of G. orensis.  PMID:25112619

  18. Cicero and Disjunctive Persuasion.

    ERIC Educational Resources Information Center

    Ochs, Donovan J.

    In his analysis of Cicero's "Philippics," Cecil Wooten (1983) describes the strategy the Roman advocate used in a rhetorical situation of national crisis as a contest of black and white, the struggle of good against evil; at stake is the very existence of the civilization that he is defending. Choices offered in crisis situations can be viewed in…

  19. From Disjunction to Multiplicity

    ERIC Educational Resources Information Center

    Greene, Maxine

    1972-01-01

    A discussion in reaction to Bell's thesis (AA 511 929) of the reflection of, and influence on, culture in art. The author focuses on literature and argues that the function of literature is to provide multiple perspectives and to influence the reader, and that this it to the good. (Author/JB)

  20. Multilocus phylogenetic analyses reveal unexpected abundant diversity and significant disjunct distribution pattern of the Hedgehog Mushrooms (Hydnum L.)

    PubMed Central

    Feng, Bang; Wang, Xiang-Hua; Ratkowsky, David; Gates, Genevieve; Lee, Su See; Grebenc, Tine; Yang, Zhu L.

    2016-01-01

    Hydnum is a fungal genus proposed by Linnaeus in the early time of modern taxonomy. It contains several ectomycorrhizal species which are commonly consumed worldwide. However, Hydnum is one of the most understudied fungal genera, especially from a molecular phylogenetic view. In this study, we extensively gathered specimens of Hydnum from Asia, Europe, America and Australasia, and analyzed them by using sequences of four gene fragments (ITS, nrLSU, tef1α and rpb1). Our phylogenetic analyses recognized at least 31 phylogenetic species within Hydnum, 15 of which were reported for the first time. Most Australasian species were recognized as strongly divergent old relics, but recent migration between Australasia and the Northern Hemisphere was also detected. Within the Northern Hemisphere, frequent historical biota exchanges between the Old World and the New World via both the North Atlantic Land Bridge and the Bering Land Bridge could be elucidated. Our study also revealed that most Hydnum species found in subalpine areas of the Hengduan Mountains in southwestern China occur in northeastern/northern China and Europe, indicating that the composition of the mycobiota in the Hengduan Mountains reigion is more complicated than what we have known before. PMID:27151256

  1. Multilocus phylogenetic analyses reveal unexpected abundant diversity and significant disjunct distribution pattern of the Hedgehog Mushrooms (Hydnum L.).

    PubMed

    Feng, Bang; Wang, Xiang-Hua; Ratkowsky, David; Gates, Genevieve; Lee, Su See; Grebenc, Tine; Yang, Zhu L

    2016-01-01

    Hydnum is a fungal genus proposed by Linnaeus in the early time of modern taxonomy. It contains several ectomycorrhizal species which are commonly consumed worldwide. However, Hydnum is one of the most understudied fungal genera, especially from a molecular phylogenetic view. In this study, we extensively gathered specimens of Hydnum from Asia, Europe, America and Australasia, and analyzed them by using sequences of four gene fragments (ITS, nrLSU, tef1α and rpb1). Our phylogenetic analyses recognized at least 31 phylogenetic species within Hydnum, 15 of which were reported for the first time. Most Australasian species were recognized as strongly divergent old relics, but recent migration between Australasia and the Northern Hemisphere was also detected. Within the Northern Hemisphere, frequent historical biota exchanges between the Old World and the New World via both the North Atlantic Land Bridge and the Bering Land Bridge could be elucidated. Our study also revealed that most Hydnum species found in subalpine areas of the Hengduan Mountains in southwestern China occur in northeastern/northern China and Europe, indicating that the composition of the mycobiota in the Hengduan Mountains reigion is more complicated than what we have known before. PMID:27151256

  2. Standardizing the Protocol for Hemispherical Photographs: Accuracy Assessment of Binarization Algorithms

    PubMed Central

    Glatthorn, Jonas; Beckschäfer, Philip

    2014-01-01

    Hemispherical photography is a well-established method to optically assess ecological parameters related to plant canopies; e.g. ground-level light regimes and the distribution of foliage within the crown space. Interpreting hemispherical photographs involves classifying pixels as either sky or vegetation. A wide range of automatic thresholding or binarization algorithms exists to classify the photographs. The variety in methodology hampers ability to compare results across studies. To identify an optimal threshold selection method, this study assessed the accuracy of seven binarization methods implemented in software currently available for the processing of hemispherical photographs. Therefore, binarizations obtained by the algorithms were compared to reference data generated through a manual binarization of a stratified random selection of pixels. This approach was adopted from the accuracy assessment of map classifications known from remote sensing studies. Percentage correct () and kappa-statistics () were calculated. The accuracy of the algorithms was assessed for photographs taken with automatic exposure settings (auto-exposure) and photographs taken with settings which avoid overexposure (histogram-exposure). In addition, gap fraction values derived from hemispherical photographs were compared with estimates derived from the manually classified reference pixels. All tested algorithms were shown to be sensitive to overexposure. Three of the algorithms showed an accuracy which was high enough to be recommended for the processing of histogram-exposed hemispherical photographs: “Minimum” ( 98.8%; 0.952), “Edge Detection” ( 98.1%; 0.950), and “Minimum Histogram” ( 98.1%; 0.947). The Minimum algorithm overestimated gap fraction least of all (11%). The overestimation by the algorithms Edge Detection (63%) and Minimum Histogram (67%) were considerably larger. For the remaining four evaluated algorithms (IsoData, Maximum Entropy, MinError, and Otsu) an

  3. Hemispheric Asymmetry in the Efficiency of Attentional Networks

    ERIC Educational Resources Information Center

    Asanowicz, Dariusz; Marzecova, Anna; Jaskowski, Piotr; Wolski, Piotr

    2012-01-01

    Despite the fact that hemispheric asymmetry of attention has been widely studied, a clear picture of this complex phenomenon is still lacking. The aim of the present study was to provide an efficient and reliable measurement of potential hemispheric asymmetries of three attentional networks, i.e. alerting, orienting and executive attention.…

  4. A Hemispheric Asymmetry for the Unconscious Perception of Emotion

    ERIC Educational Resources Information Center

    Smith, Stephen D.; Bulman-Fleming, M. Barbara

    2004-01-01

    Previous research has demonstrated that hemispheric asymmetries for conscious visual perception do not lead to asymmetries for unconscious visual perception. These studies utilized emotionally neutral items as stimuli. The current research utilized both emotionally negative and neutral stimuli to assess hemispheric differences for conscious and…

  5. Hemispheric Differences in the Organization of Memory for Text Ideas

    ERIC Educational Resources Information Center

    Long, Debra L.; Johns, Clinton L.; Jonathan, Eunike

    2012-01-01

    The goal of this study was to examine hemispheric asymmetries in episodic memory for discourse. Access to previously comprehended information is essential for mapping incoming information to representations of "who did what to whom" in memory. An item-priming-in-recognition paradigm was used to examine differences in how the hemispheres represent…

  6. Disentangling the Relationship between Hemispheric Asymmetry and Cognitive Performance

    ERIC Educational Resources Information Center

    Hirnstein, Marco; Leask, Stuart; Rose, Jonas; Hausmann, Markus

    2010-01-01

    It is widely believed that advantages of hemispheric asymmetries originated in better cognitive processing, hence it is often implied that the relationship between hemispheric asymmetry and cognitive performance is linearly positive: the higher the degree of lateralization in a specific cognitive domain, the better the performance in a…

  7. Hemispheric Differences in the Effects of Context on Vowel Perception

    ERIC Educational Resources Information Center

    Sjerps, Matthias J.; Mitterer, Holger; McQueen, James M.

    2012-01-01

    Listeners perceive speech sounds relative to context. Contextual influences might differ over hemispheres if different types of auditory processing are lateralized. Hemispheric differences in contextual influences on vowel perception were investigated by presenting speech targets and both speech and non-speech contexts to listeners' right or left…

  8. ERP Evidence of Hemispheric Independence in Visual Word Recognition

    ERIC Educational Resources Information Center

    Nemrodov, Dan; Harpaz, Yuval; Javitt, Daniel C.; Lavidor, Michal

    2011-01-01

    This study examined the capability of the left hemisphere (LH) and the right hemisphere (RH) to perform a visual recognition task independently as formulated by the Direct Access Model (Fernandino, Iacoboni, & Zaidel, 2007). Healthy native Hebrew speakers were asked to categorize nouns and non-words (created from nouns by transposing two middle…

  9. The Joint Development of Hemispheric Lateralization for Words and Faces

    ERIC Educational Resources Information Center

    Dundas, Eva M.; Plaut, David C.; Behrmann, Marlene

    2013-01-01

    Consistent with long-standing findings from behavioral studies, neuroimaging investigations have identified a region of the inferior temporal cortex that, in adults, shows greater face selectivity in the right than left hemisphere and, conversely, a region that shows greater word selectivity in the left than right hemisphere. What has not been…

  10. Assessment of Hemispheric Dominance for Language at Three Ages.

    ERIC Educational Resources Information Center

    Tegano, Deborah Walker

    The purposes of this study were to assess the development of hemispheric dominance for language function among children of 4, 7, and 10 years of age and to determine whether age predicts hemispheric dominance. Within 2 weeks of the beginning of data collection, middle-class subjects selected from private nursery schools and elementary schools…

  11. Hemispheric Specialization and the Language Abilities of Autistic Children.

    ERIC Educational Resources Information Center

    Dawson, Geraldine; And Others

    1986-01-01

    Autistic children's direction of hemispheric asymmetry in response to linguistic stimuli differed significantly from that of normal subjects, showing reversed but not necessarily reduced patterns. Autistic children with more advanced language abilities were more likely to exhibit a normal direction of hemispheric asymmetry. Implications are…

  12. Inkjet printed superparamagnetic polymer composite hemispheres with programmed magnetic anisotropy

    NASA Astrophysics Data System (ADS)

    Ergeneman, Olgaç; Peters, Christian; Gullo, Maurizio R.; Jacot-Descombes, Loïc; Gervasoni, Simone; Özkale, Berna; Fatio, Philipe; Cadarso, Victor J.; Mastrangeli, Massimo; Pané, Salvador; Brugger, Jürgen; Hierold, Christofer; Nelson, Bradley J.

    2014-08-01

    We present the fabrication and characterization of large arrays of inkjet-printed superparamagnetic polymer composite (SPMPC) hemispherical microstructures. SPMPCs are appealing for applications in microsystems and nanorobotics due to the added functionality of polymers and the significant magnetic attributes of embedded nanostructures. SPMPC-based microarchitectures can be used to perform different functions wirelessly in various media (e.g. water, solvents) using external magnetic fields: handling and assembling small objects, delivering drugs or biomass, or sensing specific physical or chemical changes. In this work superparamagnetic magnetite nanoparticles are dispersed in SU-8 to form magnetic hemispheres. Magnetically anisotropic hemispheres as well as standard SPMPC hemispheres are fabricated. Magnetic anisotropy is programmed by applying a magnetic field during curing. The distribution of nanoparticles inside the polymer matrix and magnetic characteristics of the SPMPC are investigated. Magnetic manipulation of hemispheres is demonstrated at liquid-liquid interfaces. Different assembly strategies to form lines or geometric shapes from hemispheres as well as their independent dynamic control are demonstrated. Finally, a two-interface assembly strategy is demonstrated to assemble hemispheres into complete spheres for advanced self-assembly tasks.We present the fabrication and characterization of large arrays of inkjet-printed superparamagnetic polymer composite (SPMPC) hemispherical microstructures. SPMPCs are appealing for applications in microsystems and nanorobotics due to the added functionality of polymers and the significant magnetic attributes of embedded nanostructures. SPMPC-based microarchitectures can be used to perform different functions wirelessly in various media (e.g. water, solvents) using external magnetic fields: handling and assembling small objects, delivering drugs or biomass, or sensing specific physical or chemical changes. In this

  13. Atmospheric Blocking in the Northern Hemisphere.

    NASA Astrophysics Data System (ADS)

    Knox, John Lewis

    Blocking is generally understood as the obstruction on a large scale of the normal west - to - east motion of mid-latitude pressure systems. It is a persistent phenomenon lasting from one to several weeks and the resulting prolonged weather regimes may have serious economic and social consequences. The recent Northern Hemisphere winters, starting with 1976 -77, featured unusually large circulation anomalies, many of which can be directly related to prolonged episodes of large scale blocking. The intent of this study is to investigate the statistics and certain diagnostics of blocking in the Northern Hemisphere. The first of the three primary objectives is to present and interpret the spatial and temporal distribution of blocking during the past 33 years. We develop objective identification criteria, adaptable to machine processing methods, by relating the blocking anticyclone to its associated positive anomaly of 5-day mean 500MB height. Anomalies meeting the criteria are called 'blocking signatures.' We present the seasonal frequency of occurrence of these signatures by longitude and by area. The results are in good agreement with published studies for the oceans, but they also reveal a high frequency of blocking signatures over the Northeastern Canadian Archipelago. This result, dubbed the 'Baffin Island Paradox' is further investigated and rationalized. A catalogue has been prepared which identifies the date, centre location and magnitude of every blocking signature which occurred from January 1, 1946 to December 31, 1978. A supplementary Catalogue identifies sequences of these signatures corresponding to actual blocking episodes. The second objective is to investigate whether regions with high incidence of blocking, in either the developing or the mature stage, features non-Gaussian distributions of 5-day mean geopotential. During winter, fields of significantly low kurtosis are found in certain mid-latitude regions where the genesis and amplification of

  14. Detailed Cloud Patterns in Martian Northern Hemisphere

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Cold and cloudy mornings; cool, hazy afternoons. High winds aloft and weather fronts moving slowly to the east. It is winter in the Martian northern hemisphere. One of the many reasons to study Mars is that, at times, its weather is very 'Earth-like.' At this time of the Martian year, clouds are abundant, especially in the morning and especially in the high northern latitudes. Clouds and fogs are also observed in low-lying areas farther to the south, in some lowlands they are as far south as the equator.

    The above color composite images, obtained by Mars Global Surveyor's camera on June 4, 1998, illustrate this Martian 'weather report.' Most of the thick, white clouds seen here occur north of latitude 35oN (roughly equivalent to Albuquerque NM, Memphis TN, and Charlotte, NC). Fog (seen as bright orange because it is lighter than the ground but some of the ground is still visible) occupies the lowest portions of the Kasei Valles outflow channel around 30oN and at 25oN.

    Several different types of cloud features are seen. The repetitious, wash-board pattern of parallel lines are 'gravity wave clouds'. These commonly form, in the lee--downwind side-- of topographic features such as mountain ranges (on Earth) or crater rims (on Mars), under very specific atmospheric conditions (low temperatures, high humidity, and high wind speeds). In this area, the wave clouds are lower in the atmosphere than some of the other clouds. These other clouds show attributes reflecting more the regional weather pattern, occasionally showing the characteristic 'slash' shape (southwest to northeast) of a weather front. These clouds probably contain mostly crystals of water ice but, depending on the temperature at high altitude (and more likely closer to the pole), some could also contain frozen carbon dioxide ('dry ice').

    MOC images 34501 (the red wide angle image) and 34502 (the blue wide angle image) were obtained on Mars Global Surveyor's 345th orbit about the planet

  15. Hemispherical total emissivity of Hastelloy N with different surface conditions

    NASA Astrophysics Data System (ADS)

    Gordon, Andrew J.; Walton, Kyle L.; Ghosh, Tushar K.; Loyalka, Sudarshan K.; Viswanath, Dabir S.; Tompson, Robert V.

    2012-07-01

    The hemispherical total emissivity of Hastelloy N (a candidate structural material for Next Generation Nuclear Plants (NGNPs), particularly for the molten fluoride cooled reactors) was measured using an experimental set-up that was constructed in accordance with the standard ASTM C835-06. The material surface conditions included: (i) 'as received' (original) sample from the supplier; (ii) samples with increased surface roughness through sand blasting; (iii) oxidized surface, and (iv) samples coated with graphite powder. The emissivity of the as received samples varied from around 0.22 to 0.28 in the temperature range of 473 K to 1498 K. The emissivity increased when the roughness of the surface increased compared to an as received sample. When Hastelloy N was oxidized in air at 1153 K or coated with graphite powder, its emissivity increased substantially. The sample sand blasted with 60 grit beads and sprinkled with graphite powder showed an increase of emissivity from 0.2 to 0.60 at 473 K and from 0.25 to 0.67 at 1473 K. The oxidized surface showed a similar behavior: an increase in emissivity compared to an unoxidized sample. This increase in emissivity has strong favorable safety implications in terms of decay heat removal in post-accident environments. The data were compared with another Hastelloy family member, Hastelloy X.

  16. Beyond Hemispheric Dominance: Brain Regions Underlying the Joint Lateralization of Language and Arithmetic to the Left Hemisphere

    ERIC Educational Resources Information Center

    Pinel, Philippe; Dehaene, Stanislas

    2010-01-01

    Language and arithmetic are both lateralized to the left hemisphere in the majority of right-handed adults. Yet, does this similar lateralization reflect a single overall constraint of brain organization, such an overall "dominance" of the left hemisphere for all linguistic and symbolic operations? Is it related to the lateralization of specific…

  17. Hemispheric Contributions to Lexical Ambiguity Resolution in a Discourse Context: Evidence from Individuals with Unilateral Left and Right Hemisphere Lesions

    ERIC Educational Resources Information Center

    Grindrod, C.M.; Baum, S.R.

    2005-01-01

    In the present study, a cross-modal semantic priming task was used to investigate the ability of left-hemisphere-damaged (LHD) nonfluent aphasic, right-hemisphere-damaged (RHD) and non-brain-damaged (NBD) control subjects to use a discourse context to resolve lexically ambiguous words. Subjects first heard four-sentence discourse passages ending…

  18. Europa's Northern Trailing Hemisphere: Lineament Stratigraphic Framework

    NASA Technical Reports Server (NTRS)

    Figueredo, P. H.; Hare, T.; Ricq, E.; Strom, K.; Greeley, R.; Tanaka, K.; Senske, D.

    2004-01-01

    Knowledge of the global distribution of Europan geologic units in time and space is a necessary step for the synthesis of the results of the Galileo mission and in preparation for future exploration (namely, by JIMO) of the satellite. We have initiated the production of the first Global Geological Map of Europa. As a base map, we use the recently published global photomosaic of Europa (U.S.G.S. Map I-2757) and additional Galileo SSI images at their original resolution. The map is being produced entirely on GIS format for analysis and combination with other datasets [1]. One of the main objectives of this project is to establish a global stratigraphic framework for Europa. In the absence of a well-developed cratering record, this goal will be achieved using the satellite s global network of lineaments (ridges, ridge complexes and bands; cf. [2]). Here we present the preliminary stratigraphic framework synthesized from the sequence of lineaments derived for the northern trailing hemisphere of Europa (Figure 1, below), and we discuss its significance and some emerging implications.

  19. Remote Control Southern Hemisphere SSA Observatory

    NASA Astrophysics Data System (ADS)

    Ritchie, I.; Pearson, M.; Sang, J.

    2013-09-01

    EOS Space Systems (EOSSS) is a research and development company which has developed custom observatories, camera and telescope systems for space surveillance since 1996, as well as creating several evolutions of systems control software for control of observatories and laser tracking systems. Our primary reserach observatory is the Space Reserach Centre (SRC) at Mount Stromlo Asutralia. The current SRC control systems are designed such that remote control can be offered for real time data collection, noise filtering and flexible session management. Several imaging fields of view are available simultaneously for tracking orbiting objects, with real time imaging to Mag 18. Orbiting objects can have the centroids post processed into orbital determination/ orbital projection (OD/OP) elements. With or without laser tracking of orbiting objects, they can be tracked in terminator conditions and their OD/OP data created, then enhanced by proprietary methods involving ballistic coefficient estimation and OD convergence pinning, using a priori radar elements. Sensors in development include a thermal imager for satellite thermal signature detection. Extending laser tracking range by use of adaptive optics beam control is also in development now. This Southern Hemisphere observatory is in a unique position to facilitate the study of space debris, either stand-alone or as part of a network such as Falcon. Current national and international contracts will enhance the remote control capabilities further, creating a resource ready to go for a wide variety of SSA missions.

  20. Hemispherical Stokes polarimeter for early cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Lemaillet, Paul; Ramella-Roman, Jessica C.

    2011-03-01

    Optimal treatment of skin cancer before it reaches metastasis depends critically on early diagnosis of the melanoma. Valuable information for this diagnosis can be obtained from the analysis of skin roughness. This information can aid in determining the necessity for skin removal. For this purpose, we developed a hemispherical imaging Stokes polarimeter designed to monitor skin cancer based on a roughness assessment of the epidermis. Our setup is composed of 16 out-of-plane polarized light illuminations tubes that contain a three color LED and a vertical polarizer, a Stokes polarimeter that contains 2 liquid crystal retarders, a reference vertical polarizer and a fast acquisition camera. The Stokes polarimeter was calibrated using a set of well-known input polarization states. Each illumination polarizer was positioned using a roughness gold standard and a facet model describing the principal angle of polarization of the analyzed light as a function of the angle of incidence. A set of phantoms mimicking the optical properties of skin at 633 nm as well as skin roughness was built using wax as the bulk material, titanium dioxide as the scatterer and a black dye as the absorber. Images of these phantoms are presented and they are analyzed using a facet model.

  1. Bright Ray Craters in Ganymede's Northern Hemisphere

    NASA Technical Reports Server (NTRS)

    1979-01-01

    GANYMEDE COLOR PHOTOS: This color picture as acquired by Voyager 1 during its approach to Ganymede on Monday afternoon (the 5th of March). At ranges between about 230 to 250 thousand km. The images show detail on the surface with a resolution of four and a half km. This picture is of a region in the northern hemisphere near the terminator. It shows a variety of impact structures, including both razed and unrazed craters, and the odd, groove-like structures discovered by Voyager in the lighter regions. The most striking features are the bright ray craters which have a distinctly 'bluer' color appearing white against the redder background. Ganymede's surface is known to contain large amounts of surface ice and it appears that these relatively young craters have spread bright fresh ice materials over the surface. Likewise, the lighter color and reflectivity of the grooved areas suggests that here, too, there is cleaner ice. We see ray craters with all sizes of ray patterns, ranging from extensive systems of the crater in the southern part of this picture, which has rays at least 300-500 kilometers long, down to craters which have only faint remnants of bright ejects patterns (such as several of the craters in the southern half of PIA01516; P21262). This variation suggests that, as on the Moon, there are processes which act to darken ray material, probably 'gardening' by micrometeoroid impact. JPL manages and controls the Voyager project for NASA's Office of Space Science.

  2. Objectively classifying Southern Hemisphere extratropical cyclones

    NASA Astrophysics Data System (ADS)

    Catto, Jennifer

    2016-04-01

    There has been a long tradition in attempting to separate extratropical cyclones into different classes depending on their cloud signatures, airflows, synoptic precursors, or upper-level flow features. Depending on these features, the cyclones may have different impacts, for example in their precipitation intensity. It is important, therefore, to understand how the distribution of different cyclone classes may change in the future. Many of the previous classifications have been performed manually. In order to be able to evaluate climate models and understand how extratropical cyclones might change in the future, we need to be able to use an automated method to classify cyclones. Extratropical cyclones have been identified in the Southern Hemisphere from the ERA-Interim reanalysis dataset with a commonly used identification and tracking algorithm that employs 850 hPa relative vorticity. A clustering method applied to large-scale fields from ERA-Interim at the time of cyclone genesis (when the cyclone is first detected), has been used to objectively classify identified cyclones. The results are compared to the manual classification of Sinclair and Revell (2000) and the four objectively identified classes shown in this presentation are found to match well. The relative importance of diabatic heating in the clusters is investigated, as well as the differing precipitation characteristics. The success of the objective classification shows its utility in climate model evaluation and climate change studies.

  3. Volcanoes and volcanic provinces - Martian western hemisphere

    NASA Technical Reports Server (NTRS)

    Scott, D. H.

    1982-01-01

    The recognition of some Martian landforms as volcanoes is based on their morphology and geologic setting. Other structures, however, may exhibit classic identifying features to a varying or a less degree; these may be only considered provisionally as having a volcanic origin. Regional geologic mapping of the western hemisphere of Mars from Viking images has revealed many more probable volcanoes and volcanotectonic features than were recognized on Mariner 9 pictures. These abundant volcanoes have been assigned to several distinct provinces on the basis of their areal distribution. Although the Olympus-Tharsis region remains as the principle center of volcanism on Mars, four other important provinces are now also recognized: the lowland plains, Tempe Terra plateau, southern highlands (in the Phaethontis and Thaumasia quadrangles), and a probable ignimbrite province, situated along the highland-lowland boundary in Amazonis Planitia. Volcanoes in any one province vary in morphlogy, size, and age, but volcanoes in each province tend to have common characteristics that distinguish that particular group.

  4. Modeling Hemispheric Detonation Experiments in 2-Dimensions

    SciTech Connect

    Howard, W M; Fried, L E; Vitello, P A; Druce, R L; Phillips, D; Lee, R; Mudge, S; Roeske, F

    2006-06-22

    Experiments have been performed with LX-17 (92.5% TATB and 7.5% Kel-F 800 binder) to study scaling of detonation waves using a dimensional scaling in a hemispherical divergent geometry. We model these experiments using an arbitrary Lagrange-Eulerian (ALE3D) hydrodynamics code, with reactive flow models based on the thermo-chemical code, Cheetah. The thermo-chemical code Cheetah provides a pressure-dependent kinetic rate law, along with an equation of state based on exponential-6 fluid potentials for individual detonation product species, calibrated to high pressures ({approx} few Mbars) and high temperatures (20000K). The parameters for these potentials are fit to a wide variety of experimental data, including shock, compression and sound speed data. For the un-reacted high explosive equation of state we use a modified Murnaghan form. We model the detonator (including the flyer plate) and initiation system in detail. The detonator is composed of LX-16, for which we use a program burn model. Steinberg-Guinan models5 are used for the metal components of the detonator. The booster and high explosive are LX-10 and LX-17, respectively. For both the LX-10 and LX-17, we use a pressure dependent rate law, coupled with a chemical equilibrium equation of state based on Cheetah. For LX-17, the kinetic model includes carbon clustering on the nanometer size scale.

  5. (An)isotropy of the Hubble diagram: comparing hemispheres

    NASA Astrophysics Data System (ADS)

    Schwarz, D. J.; Weinhorst, B.

    2007-11-01

    Aims:We test the isotropy of the Hubble diagram. At small redshifts, this is possible without assumptions on the cosmic inventory and provides a fundamental test of the cosmological principle. At higher redshift we check for the self-consistency of the ΛCDM model. Methods: At small redshifts, we use public supernovae (SNe) Ia data to determine the deceleration parameter q0 and the SN calibration on opposite hemispheres. For the complete data sets we fit ΩM and the SN calibration on opposite hemispheres. Results: A statistically significant anisotropy of the Hubble diagram at redshifts z < 0.2 is discovered (>95%C.L.). While data from the North Galactic hemisphere favour the accelerated expansion of the Universe, data from the South Galactic hemisphere are not conclusive. The hemispheric asymmetry is maximal toward a direction close to the equatorial poles. The discrepancy between the equatorial North and South hemispheres shows up in the SN calibration. For the ΛCDM model fitted to all available SNe, we find the same asymmetry. Conclusions: The alignment of discrepancies between hemispheric Hubble diagrams with the equatorial frame seems to point toward a systematic error in the SN search, observation, analysis or data reduction. We also find that our model independent test cannot exclude the case of the deceleration of the expansion at a statistically significant level.

  6. What Does the Right Hemisphere Know about Phoneme Categories?

    PubMed Central

    Wolmetz, Michael; Poeppel, David; Rapp, Brenda

    2015-01-01

    Innate auditory sensitivities and familiarity with the sounds of language give rise to clear influences of phonemic categories on adult perception of speech. With few exceptions, current models endorse highly left-hemisphere-lateralized mechanisms responsible for the influence of phonemic category on speech perception, based primarily on results from functional imaging and brain-lesion studies. Here we directly test the hypothesis that the right hemisphere does not engage in phonemic analysis. By using fMRI to identify cortical sites sensitive to phonemes in both word and pronounceable nonword contexts, we find evidence that right-hemisphere phonemic sensitivity is limited to a lexical context. We extend the interpretation of these fMRI results through the study of an individual with a left-hemisphere lesion who is right-hemisphere reliant for initial acoustic and phonetic analysis of speech. This individual’s performance revealed that the right hemisphere alone was insufficient to allow for typical phonemic category effects but did support the processing of gradient phonetic information in lexical contexts. Taken together, these findings confirm previous claims that the right temporal cortex does not play a primary role in phoneme processing, but they also indicate that lexical context may modulate the involvement of a right hemisphere largely tuned for less abstract dimensions of the speech signal. PMID:20350179

  7. A hemispherical dynamo model: Implications for the Martian crustal magnetization

    NASA Astrophysics Data System (ADS)

    Dietrich, W.; Wicht, J.

    2013-04-01

    Mars Global Surveyor measurements revealed that the Martian crust is strongly magnetized in the southern hemisphere while the northern hemisphere is virtually void of magnetization. Two possible reasons have been suggested for this dichotomy: a once more or less homogeneously magnetization may have been destroyed in the northern hemisphere by, for example, resurfacing or impacts. The alternative theory we further explore here assumes that the dynamo itself produced a hemispherical field (Stanley et al., 2008; Amit et al., 2011). We use numerical dynamo simulations to study under which conditions a spatial variation of the heat flux through the core-mantle boundary (CMB) may yield a strongly hemispherical surface field. We assume that the early Martian dynamo was exclusively driven by secular cooling and we mostly concentrate on a cosine CMB heat flux pattern with a minimum at the north pole, possibly caused by the impacts responsible for the northern lowlands. This pattern consistently triggers a convective mode which is dominated by equatorially anti-symmetric and axisymmetric (EAA, Landeau and Aubert, 2011) thermal winds. Convective up- and down-wellings and thus radial magnetic field production then tend to concentrate in the southern hemisphere which is still cooled efficiently while the northern hemisphere remains hot. The dynamo changes from an α2 for a homogeneous CMB heat flux to an αΩ-type in the hemispherical configuration. These dynamos reverse on time scales of about 10 kyrs. This too fast to allow for the more or less unidirectional magnetization of thick crustal layer required to explain the strong magnetization in the southern hemisphere.

  8. The orbicularis oculi response after hemispheral damage.

    PubMed Central

    Berardelli, A; Accornero, N; Cruccu, G; Fabiano, F; Guerrisi, V; Manfredi, M

    1983-01-01

    The corneal and blink reflexes were evaluated in 20 normal subjects and in 30 patients with motor deficits secondary to unilateral hemispheral lesions of vascular origin. In the normal population there were no differences between subjects below and subjects above 50 years of age. In the patients the reflex evoked by electrical stimulation of the cornea of the clinically affected side was depressed in 24 out of 30 cases. The depression mainly affected the afferent branch of the circuit, which triggers both homolateral and contralateral orbicularis oculi discharge (afferent abnormality). In three cases the depression was exerted concomitantly on the efferent branch (afferent and efferent abnormality) and only in one case was it limited to the efferent branch (efferent abnormality). The late R2 component of the blink reflex was depressed in 15 out of 30 patients. The early R1 component was slightly facilitated on the affected side. The changes of the corneal reflex and of the R2 component of blink reflex were similar, but the blink reflex had a greater safety factor. The patients with an abnormal corneal reflex had more extensive damage than had the patients with normal corneal response, as shown by computer tomography, but the site of the lesion was comparable in the two groups. Conduction through the brain stem circuits mediating the orbicularis oculi response is normally under pyramidal facilitatory influences while facial motoneurons are subjected to pyramidal inhibition. After pyramidal damage the transmission of impulses in the brain stem was slowed down, ultimately to a degree that abolished the reflex. Removal of pyramidal inhibition on facial motoneurons is probably the basis of the slight facilitation of the R1 component of the blink reflex. Images PMID:6311988

  9. A Giant Storm in Saturn's Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    Kurth, W. S.; Fischer, G.; Gurnett, D. A.; Zarka, P. M.; Dyudina, U. A.; Ingersoll, A. P.; Ewald, S. P.; Porco, C.; Wesley, A.; Go, C.; Delcroix, M.

    2011-12-01

    Beginning on December 5, 2010, an extraordinary thunderstorm developed as observed via the radio signatures of lightning using the Radio and Plasma Wave Science (RPWS) instrument and the appearance of a convective cloud in Cassini's Imaging Science System (ISS) images. These instruments as well as amateur astronomers across the globe have continued to track this storm to the present. The storm is extraordinary in that it is the first observed by Cassini in the northern hemisphere near 35 degrees planetocentric north latitude and is, by far, the largest storm observed by Cassini during its mission at Saturn and is comparable to the Great White Spot (GWS) storms observed approximately once per Saturn year. The development from the barely visible indications on December 5 to a storm of GWS status occurred over about 3 weeks. Expansion of the storm in latitude within a latitudinal gradient in the wind system of the planet resulted in an elongated eastward tail which entirely circled the planet by February 2011. The primary active cell lies in a relatively localized area around the main plume of high altitude clouds that overshoot the ammonia cloud layer due to strong vertical convection, although other, weaker cells occasionally develop within the tail. The lightning flash rate of this storm peaked at an order of magnitude higher than previously recorded storms with strokes occurring at the rate of 10 per second and the total power estimated for the storm is comparable to Saturn's total emitted power, making it a significant element of the planet's energy budget. That this storm occurred a year or so after northern vernal equinox suggests a seasonal change in the location of Saturn's thunderstorms. We will summarize observations of this extraordinary storm and update its progress as it is ongoing at the time of this writing.

  10. Musical priming by the right hemisphere post-callosotomy.

    PubMed

    Tramo, M J; Bharucha, J J

    1991-01-01

    The hemispheric representation of auditory functions mediating the perception of harmony in music was investigated in two split-brain patients using a musical chord priming task. Previous experiments in normal subjects had demonstrated that the harmonic context established by a prime chord influences the accuracy of target chord intonation judgements. Only the right hemisphere of each callosotomy patient manifested the normal interaction between harmonic relatedness and intonation. The results raise the possibility that associative auditory functions which generate expectancies for harmonic progression in music are lateralized within the right hemisphere. PMID:1857503

  11. On hemispheric differences in evoked potentials to speech stimuli

    NASA Technical Reports Server (NTRS)

    Galambos, R.; Benson, P.; Smith, T. S.; Schulman-Galambos, C.; Osier, H.

    1975-01-01

    Confirmation is provided for the belief that evoked potentials may reflect differences in hemispheric functioning that are marginal at best. Subjects were right-handed and audiologically normal men and women, and responses were recorded using standard EEG techniques. Subjects were instructed to listen for the targets while laying in a darkened sound booth. Different stimuli, speech and tone signals, were used. Speech sounds were shown to evoke a response pattern that resembles that to tone or clicks. Analysis of variances on peak amplitude and latency measures showed no significant differences between hemispheres, however, a Wilcoxon test showed significant differences in hemispheres for certain target tasks.

  12. Analysis of grounding systems in soils with hemispherical layering

    SciTech Connect

    Ma, J.; Dawalibi, F.P. ); Daily, W.K. )

    1993-10-01

    A theoretical model for the analysis of grounding systems located inside or near hemispherical soil heterogeneities is presented for the first time. Exact closed-form analytical expressions for the earth potential calculations due to current sources in different regions of this soil structure have been obtained. Numerical results are presented for different grounding systems and for different types of hemispherical soil volumes. The results clearly show that these finite hemispherical soil heterogeneities have a significant influence on the performance of grounding systems. The results obtained are in agreement with well known simple case results and converge asymptotically to the uniform soil case.

  13. Integrated fossil and molecular data reveal the biogeographic diversification of the eastern Asian-eastern North American disjunct hickory genus (Carya Nutt.).

    PubMed

    Zhang, Jing-Bo; Li, Rui-Qi; Xiang, Xiao-Guo; Manchester, Steven R; Lin, Li; Wang, Wei; Wen, Jun; Chen, Zhi-Duan

    2013-01-01

    The hickory genus (Carya) contains ca. 17 species distributed in subtropical and tropical regions of eastern Asia and subtropical to temperate regions of eastern North America. Previously, the phylogenetic relationships between eastern Asian and eastern North American species of Carya were not fully confirmed even with an extensive sampling, biogeographic and diversification patterns had thus never been investigated in a phylogenetic context. We sampled 17 species of Carya and 15 species representing all other genera of the Juglandaceae as outgroups, with eight nuclear and plastid loci to reconstruct the phylogeny of Carya. The phylogenetic positions of seven extinct genera of the Juglandaceae were inferred using morphological characters and the molecular phylogeny as a backbone constraint. Divergence times within Carya were estimated with relaxed Bayesian dating. Biogeographic analyses were performed in DIVA and LAGRANGE. Diversification rates were inferred by LASER and APE packages. Our results support two major clades within Carya, corresponding to the lineages of eastern Asia and eastern North America. The split between the two disjunct clades is estimated to be 21.58 (95% HPD 11.07-35.51) Ma. Genus-level DIVA and LAGRANGE analyses incorporating both extant and extinct genera of the Juglandaceae suggested that Carya originated in North America, and migrated to Eurasia during the early Tertiary via the North Atlantic land bridge. Fragmentation of the distribution caused by global cooling in the late Tertiary resulted in the current disjunction. The diversification rate of hickories in eastern North America appeared to be higher than that in eastern Asia, which is ascribed to greater ecological opportunities, key morphological innovations, and polyploidy. PMID:23875028

  14. Poleward bound: biological impacts of Southern Hemisphere glaciation.

    PubMed

    Fraser, Ceridwen I; Nikula, Raisa; Ruzzante, Daniel E; Waters, Jonathan M

    2012-08-01

    Postglacial recolonisation patterns are well documented for the Northern Hemisphere biota, but comparable processes in the Southern Hemisphere have only recently been examined. In the largely terrestrial Northern Hemisphere, recession of ice after the Last Glacial Maximum (LGM) allowed various taxa, including slow-moving terrestrial species, to migrate poleward. By contrast, the Southern Hemisphere polar region is completely ringed by ocean, and recolonisation of Antarctica and the sub-Antarctic islands has thus presented considerable challenges. Although a few highly dispersive marine species have been able to recolonise postglacially, most surviving high-latitude taxa appear to have persisted throughout glacial maxima in local refugia. These contrasting patterns highlight the importance of habitat continuity in facilitating biological range shifts in response to climate change. PMID:22658874

  15. Geological Mapping of the Encounter Hemisphere on Pluto

    NASA Astrophysics Data System (ADS)

    White, O. L.; Moore, J. M.; Stern, S. A.; Weaver, H. A.; Olkin, C. B.; Ennico, K.; Young, L. A.; Cheng, A. F.; New Horizons GGI Theme Team

    2016-06-01

    We present mapping of Pluto's encounter hemisphere performed to date (focusing on Sputnik Planum and the immediately surrounding area) and offer preliminary descriptions of terrains further afield that will be the subject of future mapping.

  16. Summer Temperature Anomalies for the Northern Hemisphere, 1955-2011

    NASA Video Gallery

    This visualization shows a flat map of the Earth with summertime temperature anomalies for the Northern Hemisphere. This analysis compares observed seasonal mean temperatures (June-July-August) to ...

  17. Metaliteral dreaming: a right hemisphere dominant linguistic activity.

    PubMed

    Arenson, K

    1990-06-01

    Many dream reports, which take the form of propositional speech, are more meaningful if understood as metaliteral speech. To achieve this understanding the speech sounds must be decoded according to different linguistic rules than govern propositional speech. The basic rules for metaliteral speech were outlined in a recent paper. Those rules came from empirical observation. This paper proposes that the right hemisphere is dominant for the linguistic activity of metaliteral speech because, in one way or another, the rules all seem to depend on the cognitive use of right hemisphere functions, or sometimes, on the absence of left hemisphere functions. The proposed theory rejects an exclusive role for the right hemisphere in metaliteral behavior. By recognizing the subordinate role of the left, the puzzles are solved of the story-like quality to dream reports and the central role of prosody in decoding metaliteral speech. PMID:2197651

  18. Large Craters in Callisto's Southern Hemisphere

    NASA Technical Reports Server (NTRS)

    1997-01-01

    NASA's Galileo spacecraft provides a new view of this heavily cratered region in the southern hemisphere of the icy Jovian satellite Callisto. The region was not observed by NASA's Voyager spacecraft. Craters ranging in diameter from the 1.85 kilometer (1.13 mile) limit of resolution up to more than 70 kilometers (43 miles) can be observed in this image. Although all craters are generally round in outline, details in their structures vary with both size and relative age. Bright spots in the center of smaller craters (up to approximately 20 kilometers (12 miles)) are central peaks. Larger craters (up to the 51 kilometer (31 mile) wide crater in the east central part of the image) exhibit central pits or depressions. The largest crater, called Thrainn, has a diameter of 74 kilometers (45 miles) and is located in the southernmost corner of the image. This crater contains a broad central uplift, or dome, and has a highly eroded rim. In contrast, the 70 kilometer (43 mile) crater Audr, located along the northern margin of the image, is flat-bottomed, and has a less degraded and generally rounder rim. If erosional or degradational forces have been roughly constant with time on Callisto, scientists viewing this image can assume that Audr is relatively younger than Thrainn by noting the less degraded or fresher appearance of its rim. The differences in crater floor features between these two similarly sized craters could have been produced by differences in the impacting bodies that produced them, differences in the crustal materials in which the craters formed, or simply by a gradual evolution of crater floor shape with time.

    North is to the top of the image which was taken by the Galileo spacecraft's solid state imaging (CCD) system during its eighth orbit around Jupiter on May 6th, 1997. The center of the image is located at 34 degrees south latitude, 84 degrees west longitude, and was taken when the spacecraft was approximately 48,430 kilometers (29,542 miles) from

  19. Highly regioselective hydroformylation with hemispherical chelators.

    PubMed

    Sémeril, David; Matt, Dominique; Toupet, Loïc

    2008-01-01

    The hemispherical diphosphites (R,R)- or (S,S)-5,11,17,23-tetra-tert-butyl-25,27-di(OR)-26,28-bis(1,1'-binaphthyl-2,2'-dioxyphosphanyloxy)calix[4]arene (R=OPr, OCH(2)Ph, OCH(2)-naphtyl, O-fluorenyl; R=H, R'=OPr) (L(R)), all with C(2) symmetry, have been synthesised starting from the appropriate di-O-alkylated calix[4]arene precursor. In the presence of [Rh(acac)(CO)(2)], these ligands straightforwardly provide chelate complexes in which the metal centre sits in a molecular pocket defined by two naphthyl planes related by the C(2) axis and the two apically situated R groups. Hydroformylation of octene with the L(Pr)/Rh system turned out to be highly regioselective, the linear-to-branched (l:b) aldehyde ratio reaching 58:1. The l:b ratio significantly increased when the propyl groups were replaced by -CH(2)Ph (l:b=80) or -CH(2)naphthyl (l:b=100) groups, that is, with substituents able to sterically interact with the apical metal sites, but without inducing an opening of the cleft nesting the catalytic centre. The trend to preferentially form the aldehyde the shape of which fits with the shape of the catalytic pocket was further confirmed in the hydroformylation of styrene, for which, in contrast to catalysis with conventional diphosphanes, the linear aldehyde was the major product (up to ca. 75 % linear aldehyde). In the hydroformylation of trans-2-octene with the L(benzyl)/Rh system, combined isomerisation/hydroformylation led to a remarkably high l:b aldehyde ratios of 25, thus showing that isomerisation is more effective than hydroformylation. Unusually large amounts of linear products were also observed with all the above diphosphites in the tandem hydroformylation/amination of styrene (l:b of ca. 3:1) as well as in the hydroformylation of allyl benzyl ether (l:b ratio up to 20). PMID:18686280

  20. Elemental Water Impact Test: Phase 1 20-Inch Hemisphere

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.

    2015-01-01

    Spacecraft are being designed based on LS-DYNA simulations of water landing impacts. The Elemental Water Impact Test (EWIT) series was undertaken to assess the accuracy of LS-DYNA water impact simulations. Phase 1 of the EWIT series featured water impact tests of a 20-inch hemisphere dropped from heights of 5 feet and 10 feet. The hemisphere was outfitted with an accelerometer and three pressure gages. The focus of this report is the correlation of analytical models against test data.

  1. RIGHT HEMISPHERIC FUNCTION IN NORMALS, AFFECTIVE DISORDER AND SCHIZOPHRENIA

    PubMed Central

    Borde, Milind; Roy, Amal; Davis, Elizabeth J.B.; Davis, Rachel

    1996-01-01

    The happy-sad chimeric faces test has been established as a useful test of right hemispheric function. It is known to elicit a left hemifacial bias (LHF bias) in right handed subjects. 41 normals and 19 manic, depressive and schizophrenic patients each were tested. All subjects were strictly right handed. Normals and depressives showed significant LHF bias. Monies and schizophrenics did not show significant LHF Bias. This suggests right hemispheric dysfunction in both mania and schizophrenia. PMID:21584135

  2. Hemispheric asymmetry in the efficiency of attentional networks.

    PubMed

    Asanowicz, Dariusz; Marzecová, Anna; Jaśkowski, Piotr; Wolski, Piotr

    2012-07-01

    Despite the fact that hemispheric asymmetry of attention has been widely studied, a clear picture of this complex phenomenon is still lacking. The aim of the present study was to provide an efficient and reliable measurement of potential hemispheric asymmetries of three attentional networks, i.e. alerting, orienting and executive attention. Participants (N=125) were tested with the Lateralized Attention Network Test (LANT) that allowed us to investigate the efficiency of the networks in both visual fields (VF). We found a LVF advantage when a target occurred in an unattended location, which seems to reflect right hemisphere superiority in control of the reorienting of attention. Furthermore, a LVF advantage in conflict resolution was observed, which may indicate hemispheric asymmetry of the executive network. No VF effect for alerting was found. The results, consistent with the common notion of general right hemisphere dominance for attention, provide a more detailed account of hemispheric asymmetries of the attentional networks than previous studies using the LANT task. PMID:22475579

  3. Category Membership and Semantic Coding in the Cerebral Hemispheres.

    PubMed

    Turner, Casey E; Kellogg, Ronald T

    2016-01-01

    Although a gradient of category membership seems to form the internal structure of semantic categories, it is unclear whether the 2 hemispheres of the brain differ in terms of this gradient. The 2 experiments reported here examined this empirical question and explored alternative theoretical interpretations. Participants viewed category names centrally and determined whether a closely related or distantly related word presented to either the left visual field/right hemisphere (LVF/RH) or the right visual field/left hemisphere (RVF/LH) was a member of the category. Distantly related words were categorized more slowly in the LVF/RH relative to the RVF/LH, with no difference for words close to the prototype. The finding resolved past mixed results showing an unambiguous typicality effect for both visual field presentations. Furthermore, we examined items near the fuzzy border that were sometimes rejected as nonmembers of the category and found both hemispheres use the same category boundary. In Experiment 2, we presented 2 target words to be categorized, with the expectation of augmenting the speed advantage for the RVF/LH if the 2 hemispheres differ structurally. Instead the results showed a weakening of the hemispheric difference, arguing against a structural in favor of a processing explanation. PMID:27424416

  4. Phase Relationships of Solar Hemispheric Toroidal and Poloidal Cycles

    NASA Astrophysics Data System (ADS)

    Muraközy, J.

    2016-08-01

    The solar northern and southern hemispheres exhibit differences in their intensities and time profiles of the activity cycles. The time variation of these properties was studied in a previous article covering the data from Cycles 12–23. The hemispheric phase lags exhibited a characteristic variation: the leading role was exchanged between hemispheres every four cycles. The present work extends the investigation of this variation using the data of Staudacher and Schwabe in Cycles 1–4 and 7–10 as well as Spörer’s data in Cycle 11. The previously observed variation cannot be clearly recognized using the data of Staudacher, Schwabe, and Spörer. However, it is more interesting that the phase lags of the reversals of the magnetic fields at the poles follow the same variations as those of the hemispheric cycles in Cycles 12–23, i.e., one of the hemispheres leads in four cyles and the leading role jumps to the opposite hemisphere in the next four cycles. This means that this variation is a long-term property of the entire solar dynamo mechanism, for both the toroidal and poloidal fields, which hints at an unidentified component of the process responsible for the long-term memory.

  5. Stereotyping, self-affirmation, and the cerebral hemispheres.

    PubMed

    Shrira, Ilan; Martin, Leonard L

    2005-06-01

    The authors used the processing characteristics of the left and right cerebral hemispheres to gain some insight into the relation between self-affirmation and stereotyping. In Study 1, self-affirmation led to greater stereotyping (of a librarian) and to greater left hemisphere activation, which in turn mediated the self-affirmation/stereotyping relationship. Study 2 replicated these results but also found that self-affirmation decreased stereotyping for a stigmatized target. However, relative hemisphere activation did not mediate this self-affirmation/stereotyping relationship. These studies showed that self-affirmation can either increase or decrease stereotyping depending on the status of the target and that relative hemisphere activation may provide clues as to underlying processes of stereotyping. In both studies, relative hemisphere activation was assessed using a line bisection task. Discussion focuses on possible mechanisms of different kinds of stereotyping and on the ways in which a consideration of relative hemisphere activation could help researchers gain insights into those mechanisms. PMID:15833910

  6. Thermal infrared (2.5- to 13.5-µm) directional hemispherical reflectance of leaves

    USGS Publications Warehouse

    Salisbury, J.W.; Milton, N.M.

    1988-01-01

    Previous biconical reflectance measurements of 13 different plant species have shown that leaves display spectral signatures in the 8- to 14-??m atmospheric window that vary with species. Directional hemispherical reflectance measurements of six species reported here document the absolute magnitude of such spectral features for the first time. If half of the spectral contrast in leaf spectra is preserved in emittance from a broad-leaf planophile canopy, then at least some broad-leafed species could be mapped remotely by using currently available airborne instrumentation. -Authors

  7. Evidence of inter-hemispheric temperature contrasts over the last millennium from a new Southern Hemisphere multi-proxy reconstruction

    NASA Astrophysics Data System (ADS)

    Neukom, Raphael; Gergis, Joëlle; Karoly, David; Wanner, Heinz; Curran, Mark; Elbert, Julie; González-Rouco, Fidel; Linsley, Braddock; Moy, Andrew; Mundo, Ignacio; Raible, Christoph; Steig, Eric; van Ommen, Tas; Vance, Tessa; Villalba, Ricardo; Zinke, Jens; Frank, David

    2014-05-01

    The instrumental temperature record shows distinct inter-hemispheric temperature differences superimposed on the common warming trend over the last 150 years. Asynchronicity between the hemispheres is also suggested by millennial-scale analyses over the last deglaciation and the Holocene, indicating a significant modulation of the response to external forcing by internal climate system variability on multiple temporal scales. However, on multi-decadal to centennial times-scales, quantitative analyses on inter-hemispheric temperature variability are largely missing due to the lack of hemispheric-scale high-resolution reconstructions from the Southern Hemisphere. We introduce a new annually resolved multi-proxy ensemble reconstruction of Southern Hemisphere mean temperatures over the last 1000 years. The reconstruction is based on an unprecedented network of 325 proxy records yielding 111 temperature sensitive predictors. In 99.7% of the reconstruction ensemble members, the warmest decade of the last millennium occurs after 1970. Comparing our results with an ensemble of Northern Hemisphere mean reconstructions, we identify periods, where both hemispheres simultaneously exhibit extreme temperatures (defined as exceeding ±1 standard deviations of 1000-2000 temperatures). The only pre-industrial period where >33% of ensemble members indicate globally synchronous extremes is the cold phase between 1594 and 1677. Simultaneous warm temperatures are only identified in the years after 1974 (1979) where more than 66% (90%) of ensemble members indicate extreme warmth. This suggests existence of a globally coherent peak 'Little Ice Age', but no consistent 'Medieval Climate Anomaly' during last 1000 years. We then compare our ensemble of temperature reconstructions to an ensemble of 24 climate model simulations. While the simulated globally consistent cold periods coincide with major volcanic eruptions, the simulations do not account for key features of reconstructed

  8. Non-conjugate aurora and inter hemispheric currents

    NASA Astrophysics Data System (ADS)

    Reistad, J. P.; Østgaard, N.; Laundal, K. M.; Oksavik, K.

    2012-04-01

    We look at large scale auroral features using global imagers to obtain simultaneous pictures of both the southern and northern auroral ovals in the ultra violet part of the spectra. During the years 2001 and 2002 the IMAGE satellite was in a favourable position for imaging the aurora borealis (Northern Hemisphere) and the POLAR satellite with its large field-of-view VIS Earth camera had a sporadic coverage of the aurora australis (Southern Hemisphere). In total 19 hours of simultaneous global imaging from different seasons are analysed searching for non-conjugacy in the night side sector. By non-conjugate aurora we mean auroral features appearing in one hemisphere only, or significant differences in intensity between the hemispheres for the same auroral feature. We suggest that our observed large scale asymmetries can be explained in terms of inter hemispheric currents (IHC). Coherent with our earlier findings, we list three possible candidates for producing such inter hemispheric currents based on observations. 1) Hemispherical differences in the solar wind dynamo due to IMF Bx and tilt angle producing different strength of region 1 currents in the conjugate he mispheres, 2) Hemispherical differences in conductivity controlled by the tilt angle only giving rise to IHC on closed field lines, and 3) Field-aligned current components induced by the penetration of the IMF By into the closed magnetosphere. Most of the observed non-conjugate aurora in our dataset can be explained by these candidates only. The IMF By penetration candidate is considered closer. We search for evidence in our data that IMF By < 0 (By > 0) can induce an IHC producing stronger aurora on the polar boundary in the Northern (Southern) Hemisphere. Also a second IHC component are predicted from the theory, mapping to the equatorward part of the oval and opposite directed along the magnetic field lines. Using a much larger dataset for one hemisphere only, we show whether these predicted currents can

  9. Does Each Hemisphere Monitor the Ongoing Process in the Contralateral One?

    ERIC Educational Resources Information Center

    Hochman, Eldad Yitzhak; Eviatar, Zohar

    2004-01-01

    The present study was conducted to examine hemispheric division of labor in the initial processing and error monitoring in tasks for which hemispheric specialization exists. We used lexical decision as a left hemisphere task and bargraph judgment as a right hemisphere task, and manipulated cognitive load. Participants had to respond to one of two…

  10. An Examination of the Right-Hemisphere Hypothesis of the Lateralization of Emotion

    ERIC Educational Resources Information Center

    Smith, S.D.; Bulman-Fleming, M.B.

    2005-01-01

    The Right-Hemisphere Hypothesis posits that emotional stimuli are perceived more efficiently by the right hemisphere than by the left hemisphere. The current research examines this hypothesis by examining hemispheric asymmetries for the conscious and unconscious perception of emotional stimuli. Negative, positive, and neutral words were presented…

  11. High Q diamond hemispherical resonators: fabrication and energy loss mechanisms

    NASA Astrophysics Data System (ADS)

    Bernstein, Jonathan J.; Bancu, Mirela G.; Bauer, Joseph M.; Cook, Eugene H.; Kumar, Parshant; Newton, Eric; Nyinjee, Tenzin; Perlin, Gayatri E.; Ricker, Joseph A.; Teynor, William A.; Weinberg, Marc S.

    2015-08-01

    We have fabricated polycrystalline diamond hemispheres by hot-filament CVD (HFCVD) in spherical cavities wet-etched into a high temperature glass substrate CTE matched to silicon. Hemispherical resonators 1.4 mm in diameter have a Q of up to 143 000 in the fundamental wineglass mode, for a ringdown time of 2.4 s. Without trimming, resonators have the two degenerate wineglass modes frequency matched as close as 2 Hz, or 0.013% of the resonant frequency (~16 kHz). Laser trimming was used to match resonant modes on hemispheres to 0.3 Hz. Experimental and FEA energy loss studies on cantilevers and hemispheres examine various energy loss mechanisms, showing that surface related losses are dominant. Diamond cantilevers with a Q of 400 000 and a ringdown time of 15.4 s were measured, showing the potential of polycrystalline diamond films for high Q resonators. These resonators show great promise for use as hemispherical resonant gyroscopes (HRGs) on a chip.

  12. [Independent resource of each hemisphere modulates selective attention].

    PubMed

    Yoshizaki, Kazuhito; Nishimura, Ritsuko

    2008-06-01

    Based on the load theory and the assumption that each hemisphere has independent resources, we examined the effects of perceptual load in each hemisphere on the compatibility effect. In Experiments 1, and 2ab, two letter-strings were presented to the left and right visual-fields with a distracter, which was presented on the center of the screen. Two conditions were prepared by pairing a letter-string which contained a target with one which did not. Right-handed participants were asked to identify the target in the letter-strings while ignoring the distracter. The results showed that the compatibility effect was larger when the perceptual load of the letter-string which did not contain a target was low. This suggests that the residual resources of the hemisphere where the target was not projected facilitated the processing of the distracter. In Experiment 3, two letter-strings were presented to both hemispheres. The results showed that the compatibility effect was constant, irrespective of the perceptual load of the letter-string. Our findings suggested that selective attention is modulated by the resources of each hemisphere. PMID:18678063

  13. Mechanisms of hemispheric specialization: Insights from analyses of connectivity

    PubMed Central

    Stephan, Klaas Enno; Fink, Gereon R.; Marshall, John C.

    2007-01-01

    Traditionally, anatomical and physiological descriptions of hemispheric specialization have focused on hemispheric asymmetries of local brain structure or local functional properties, respectively. This article reviews the current state of an alternative approach that aims at unraveling the causes and functional principles of hemispheric specialization in terms of asymmetries in connectivity. Starting with an overview of the historical origins of the concept of lateralization, we briefly review recent evidence from anatomical and developmental studies that asymmetries in structural connectivity may be a critical factor shaping hemispheric specialization. These differences in anatomical connectivity, which are found both at the intra- and inter-regional level, are likely to form the structural substrate of different functional principles of information processing in the two hemispheres. The main goal of this article is to describe how these functional principles can be characterized using functional neuroimaging in combination with models of functional and effective connectivity. We discuss the methodology of established models of connectivity which are applicable to data from positron emission tomography and functional magnetic resonance imaging and review published studies that have applied these approaches to characterize asymmetries of connectivity during lateralized tasks. Adopting a model-based approach enables functional imaging to proceed from mere descriptions of asymmetric activation patterns to mechanistic accounts of how these asymmetries are caused. PMID:16949111

  14. ERP evidence of hemispheric independence in visual word recognition.

    PubMed

    Nemrodov, Dan; Harpaz, Yuval; Javitt, Daniel C; Lavidor, Michal

    2011-09-01

    This study examined the capability of the left hemisphere (LH) and the right hemisphere (RH) to perform a visual recognition task independently as formulated by the Direct Access Model (Fernandino, Iacoboni, & Zaidel, 2007). Healthy native Hebrew speakers were asked to categorize nouns and non-words (created from nouns by transposing two middle letters) into man-made and natural categories while their performance and ERPs were recorded. The stimuli were presented parafoveally to the right and left visual fields. As predicted by the Direct Access Model, ERP data showed that both the left hemisphere and right hemisphere were able to differentiate between words and non-words as early as 170 ms post-stimulus; these results were significant only for the contralaterally presented stimuli. The N1 component, which is considered to reflect orthographic processing, was larger in both hemispheres in response to the contralateral than the ipsilateral presented stimuli. This finding provides evidence for the RH capability to access higher level lexical information at the early stages of visual word recognition, thus lending weight to arguments for the relatively independent nature of this process. PMID:20542549

  15. On inter-hemispheric coupling in the middle atmosphere

    NASA Astrophysics Data System (ADS)

    Karlsson, Bodil; Bailey, S.; Benze, S.; Gumbel, J.; Harvey, V. L.; Kürnich, H.; Lossow, S.; McLandress, D. Marsh, C.; Merkel, A. W.; Mills, M.; Randall, C. E.; Russell, J.; Shepherd, T. G.

    On inter-hemispheric coupling in the middle atmosphere From recent studies it is evident that planetary wave activity in the winter hemisphere influences the high-latitude summer mesosphere on the opposite side of the globe. This is an extraordinary example of multi-scale wave-mean flow interaction. The first indication of this inter-hemispheric coupling came from a model study by Becker and Schmitz (2003). Since then, the results have been reproduced in several models, and observations have confirmed the existence of this link. We present current understanding of inter-hemispheric coupling and its consequences for the middle atmosphere, focusing on the summer mesosphere where polar mesospheric clouds (PMCs) form. The results shown are based on year-to-year and intra-seasonal variability in PMCs ob-served by the Odin satellite and the Aeronomy of Ice in the Mesosphere (AIM) satellite, as well as on model results from the extended Canadian Middle Atmosphere Model (CMAM), the Whole Atmosphere Community Climate Model (WACCM) and the Kühlungsborn Mechanis-u tic general Circulation Model (KMCM). The latter has been used to pinpoint the proposed mechanism behind the inter-hemispheric coupling.

  16. The imprint of climate within Northern Hemisphere trees

    NASA Astrophysics Data System (ADS)

    St. George, Scott; Ault, Toby R.

    2014-04-01

    Here we show how the seasonality and strength of climate signals recorded by tree-ring widths changes across the Northern Hemisphere, and outline major regional differences in the climate 'window' sensed by trees that both constrain and augment our ability to interpret these records as paleoclimatic proxies. After surveying nearly 2200 ring-width records, we find the spatial structure of tree-climate relations across the hemisphere matches behavior predicted several decades ago very closely, confirming the principles that guide dendroclimatology are robust despite the complexity of interactions between climate, ecology and tree biology. We also show that climate filtering conducted by individual trees creates major regional differences in information that may be recovered from the hemispheric network. This behavior can introduce geographic biases to dendroclimatic reconstructions, but it also may be useful to evaluate the success of reconstruction techniques that explicitly represent the physical processes linking climate to tree growth.

  17. An asymmetric inhibition model of hemispheric differences in emotional processing

    PubMed Central

    Grimshaw, Gina M.; Carmel, David

    2014-01-01

    Two relatively independent lines of research have addressed the role of the prefrontal cortex in emotional processing. The first examines hemispheric asymmetries in frontal function; the second focuses on prefrontal interactions between cognition and emotion. We briefly review each perspective and highlight inconsistencies between them. We go on to describe an alternative model that integrates approaches by focusing on hemispheric asymmetry in inhibitory executive control processes. The asymmetric inhibition model proposes that right-lateralized executive control inhibits processing of positive or approach-related distractors, and left-lateralized control inhibits negative or withdrawal-related distractors. These complementary processes allow us to maintain and achieve current goals in the face of emotional distraction. We conclude with a research agenda that uses the model to generate novel experiments that will advance our understanding of both hemispheric asymmetries and cognition-emotion interactions. PMID:24904502

  18. Trends in Northern Hemisphere surface cyclone frequency and intensity

    USGS Publications Warehouse

    McCabe, G.J.; Clark, M.P.; Serreze, M.C.

    2001-01-01

    One of the hypothesized effects of global warming from increasing concentrations of greenhouse gases is a change in the frequency and/or intensity of extratropical cyclones. In this study, winter frequencies and intensities of extratropical cyclones in the Northern Hemisphere for the period 1959-97 are examined to determine if identifiable trends are occurring. Results indicate a statistically significant decrease in midlatitude cyclone frequency and a significant increase in high-latitude cyclone frequency. In addition, storm intensity has increased in both the high and midlatitudes. The changes in storm frequency correlate with changes in winter Northern Hemisphere temperature and support hypotheses that global warming may result in a northward shift of storm tracks in the Northern Hemisphere.

  19. Weighted frequency-difference EIT measurement of hemisphere phantom

    NASA Astrophysics Data System (ADS)

    Ahn, Sujin; In Oh, Tong; Jun, Sung Chan; Lee, Jeehyun; Seo, Jin Keun; Woo, Eung Je

    2010-04-01

    We have proposed a new frequency difference method using a weighted voltage difference (WFD-EIT) between two frequencies [1, 2]. Previous studies demonstrated its feasibility through numerical experiments and two-dimensional phantom experiments. In this study, we validate the WFD-EIT algorithm on a three-dimensional hemisphere phantom using a multi-frequency EIT system KHU Mark1. We built the hemisphere phantom with 17 stainless-steel electrodes on its inner surface. We filled the phantom with a biological material having a frequency-dependent admittivity such as carrot pieces mixed in saline. Using boundary voltage data from the deformed phantom, we reconstructed weighted frequency difference images on the computational model domain with a hemisphere shape. We discuss comparative reconstruction performance results including time difference (TD), simple frequency difference (FD), and weighted frequency difference (WFD). Animal and human head imaging experiments with the weighted frequency-difference EIT method are under investigation.

  20. Hemispheric lateralization of singing after intracarotid sodium amylobarbitone.

    PubMed

    Gordon, H W; Bogen, J E

    1974-06-01

    Hemispheric lateralization of singing was investigated in patients who had transient hemiplegia after intracarotid injection of sodium amylobarbitone. It was found that after right carotid injection singing was markedly deficient, whereas speech remained relatively intact. Songs were sung in a monotone, devoid of correct pitch rendering; rhythm was much less affected. By contrast, singing was less disturbed than speech after left carotid injection. The observations indicated a double dissociation; the right hemisphere contributed more for singing, whereas the left demonstrated its usual dominance for speech. A model is proposed that encompasses audible stimuli as well as tactual or visual into a scheme of functional lateralization wherein the right hemisphere specializes in processing a complete, time-independent stimulus configuration and the left in a series of successive, time-dependent units. PMID:4844140

  1. Asymmetric field-aligned currents in the conjugate hemispheres

    NASA Astrophysics Data System (ADS)

    Reistad, J. P.; Ostgaard, N.; Oksavik, K.; Laundal, K. M.

    2012-12-01

    Earlier studies using simultaneous imaging from space of the Aurora Borealis (Northern Hemisphere) and Aurora Australis (Southern Hemisphere) have revealed that the aurora can experience a high degree of asymmetry between the two hemispheres. Using 19 hours of simultaneous global imaging from both hemispheres (IMAGE satellite in north and Polar satellite in south) in conjunction with the entire IMAGE WIC database, we investigate the importance of various mechanisms thought to generate the asymmetries seen in global imaging. In terms of asymmetric or interhemispheric field-aligned currents, three candidate mechanisms have been suggested: 1) Hemispheric differences in solar wind dynamo efficiency mainly controlled by IMF Bx leading to asymmetric region 1 currents; 2) conductivity differences in conjugate areas; and 3) penetration of IMF By into the closed magnetosphere possibly generating a pair of oppositely directed interhemispheric currents. From the 19 hour conjugate dataset we find that the solar wind dynamo is likely to be the most important controlling mechanism for asymmetric bright aurora in the polar part of the nightside oval. Here we present statistical analyses of candidates 1) and 3). Using the entire IMAGE WIC database, a statistical analysis of the auroral brightness distribution along and across the Northern Hemisphere oval is carried out. For each candidate, two extreme cases (+/- IMF Bx for 1) and +/- IMF By for 3)) are compared during times non-favorable for the other two mechanisms. Our results indicate that solar wind dynamo induced currents play an important role for the nightside auroral brightness in an average sense. Also, signatures of interhemispheric currents due to IMF By penetration are seen in our statistics, although this effect is somehow weaker.

  2. Hemispheric lateralization of verbal and spatial working memory during adolescence

    PubMed Central

    Nagel, Bonnie J.; Herting, Megan M.; Maxwell, Emily C.; Bruno, Richard; Fair, Damien

    2013-01-01

    Adult functional magnetic resonance imaging (fMRI) literature suggests that a left-right hemispheric dissociation may exist between verbal and spatial working memory (WM), respectively. However, investigation of this type has been obscured by incomparable verbal and spatial WM tasks and/or visual inspection at arbitrary thresholds as means to assess lateralization. Furthermore, it is unclear whether this hemispheric lateralization is present during adolescence, a time in which WM skills are improving, and whether there is a developmental association with laterality of brain functioning. This study used comparable verbal and spatial WM n-back tasks during fMRI and a bootstrap analysis approach to calculate lateralization indices (LI) across several thresholds to examine the potential of a left-right WM hemispheric dissociation in healthy adolescents. We found significant left hemispheric lateralization for verbal WM, most notably in the frontal and parietal lobes, as well as right hemisphere lateralization for spatial WM, seen in frontal and temporal cortices. Although no significant relationships were observed between LI and age or LI and performance, significant age-related patterns of brain activity were demonstrated during both verbal and spatial WM. Specifically, increased adolescent age was associated with less activity in the default mode brain network during verbal WM. In contrast, increased adolescent age was associated with greater activity in task-positive posterior parietal cortex during spatial working memory. Our findings highlight the importance of utilizing non-biased statistical methods and comparable tasks for determining patterns of functional lateralization. Our findings also suggest that, while a left-right hemispheric dissociation of verbal and spatial WM is apparent by early adolescence, age-related changes in functional activation during WM are also present. PMID:23511846

  3. Multiple planetary flow regimes in the Southern Hemisphere

    NASA Technical Reports Server (NTRS)

    Yoden, Shigeo; Shiotani, Masato; Hirota, Isamu

    1987-01-01

    Low-frequency variations in the general circulation of the Southern Hemisphere during 1983 were studied using daily geopotential height and temperature analyses for 12 pressure levels from 1000 mb up to 50 mb, performed by the National Meteorological Center of Japan. Results disclosed the presence, in the Southern Hemisphere troposphere, of an irregular fluctuation of two zonal mean geostrophic wind patterns (named single-jet and double-jet regimes) during wintertime. The fluctuation is characterized by the persistence of one geostrophic wind regime, with characteristic duration of a month, followed by a rather rapid transition to another regime.

  4. Geology of the southern hemisphere of Triton: No polar cap

    NASA Technical Reports Server (NTRS)

    Schenk, P.; Moore, J. M.

    1993-01-01

    The bright southern hemisphere, comprising Uhlanga Regio, is perhaps the most poorly understood geologic province on Triton. The entire bright southern hemisphere has been described as a bright polar 'cap', implying a seasonal origin, or as a permanent geologic terrain distinct from the equatorial terrains. Also, thermal models have predicted seasonal migration of frosts and ices from the presently sun-lit south latitudes to the dark northern latitudes. The distribution of frosts and geologic history of this region must be determined observationally. We reexamine the geology of this terrain with the goal of answering these questions.

  5. Plane and hemispherical potential structures in magnetically expanding plasmas

    SciTech Connect

    Takahashi, Kazunori; Igarashi, Yuichi; Fujiwara, Tamiya

    2010-07-26

    Two-dimensional potential structures are measured for different gas pressure in expanding argon plasma using permanent magnets, where the magnetic field is about 100 G in the source and several gauss in the diffusion chamber. The plane potential drop is observed near the source exit for 0.35 mTorr, while the potential structure becomes hemispherical when increasing up to 1 mTorr; the hemispherical structure results in the radial divergence of the ion beam. It is found that the trajectories of the accelerated ions and the electrons overcoming the potential drop are dominated by the potential structure and magnetic-field lines, respectively.

  6. Mixing with piecewise isometries on a hemispherical shell

    NASA Astrophysics Data System (ADS)

    Park, Paul P.; Umbanhowar, Paul B.; Ottino, Julio M.; Lueptow, Richard M.

    2016-07-01

    We introduce mixing with piecewise isometries (PWIs) on a hemispherical shell, which mimics features of mixing by cutting and shuffling in spherical shells half-filled with granular media. For each PWI, there is an inherent structure on the hemispherical shell known as the exceptional set E, and a particular subset of E, E+, provides insight into how the structure affects mixing. Computer simulations of PWIs are used to visualize mixing and approximations of E+ to demonstrate their connection. While initial conditions of unmixed materials add a layer of complexity, the inherent structure of E+ defines fundamental aspects of mixing by cutting and shuffling.

  7. Quasi-static axisymmetric eversion hemispherical domes made of elastomers

    NASA Astrophysics Data System (ADS)

    Kabrits, Sergey A.; Kolpak, Eugeny P.

    2016-06-01

    The paper considers numerical solution for the problem of quasi-static axisymmetric eversion of a spherical shell (hemisphere) under action of external pressure. Results based on the general nonlinear theory of shells made of elastomers, proposed by K. F. Chernykh. It is used two models of shells based on the hypotheses of the Kirchhoff and Timoshenko, modified K.F. Chernykh for the case of hyperelastic rubber-like material. The article presents diagrams of equilibrium states of eversion hemispheres for both models as well as the shape of the shell at different points in the diagram.

  8. CMB hemispherical asymmetry: long mode modulation and non-Gaussianity

    SciTech Connect

    Namjoo, Mohammad Hossein; Baghram, Shant; Firouzjahi, Hassan; Abolhasani, Ali Akbar E-mail: abolhasani@ipm.ir E-mail: firouz@ipm.ir

    2014-08-01

    The observed hemispherical asymmetry in CMB map can be explained by modulation from a long wavelength super horizon mode which non-linearly couples to the CMB modes. We address the criticism in [1] about the role of non-Gaussianities in squeezed and equilateral configurations in generating hemispherical asymmetry from the long mode modulation. We stress that the modulation is sensitive to the non-Gaussianity in the squeezed limit. In addition, we demonstrate the validity of our approach in providing a consistency condition relating the amplitude of dipole asymmetry to f{sub NL} in the squeezed limit.

  9. Nitrogen deposition in a southern hemisphere biodiversity hotspot within and surrounding Cape Town, South Africa

    NASA Astrophysics Data System (ADS)

    Angstmann, J. L.; Hall, S.; February, E.; West, A. G.; Allsopp, N.; Bond, W.

    2011-12-01

    Anthropogenic nitrogen (N) emissions have increased dramatically since the agricultural and industrial revolutions leading to N deposition in the northern hemisphere that is estimated to be an order of magnitude greater than preindustrial fluxes. N deposition rates of 5-15 kg N ha-1 yr-1 in Europe and N. America decrease plant species diversity, increase invasive species, and lead to eutrophication of surface waters. The southern hemisphere is home to over 50% of the world's biodiversity hotspots, including the 90,000 km2 Cape Floristic Region which houses 9,030 vascular plant species, 69% of which are endemic. However, to date, N deposition rates in the southern hemisphere are highly uncertain, with global models of N deposition based upon sparse datasets at best. Many terrestrial systems, such as fynbos shrublands, are adapted to low N availability and exhibit high species diversity and endemism, rendering them susceptible to ecological changes from N deposition. In this research, we quantified the spatial and temporal distribution of wet and dry N deposition across 30 protected fynbos ecosystems within the urban airshed of Cape Town, South Africa. We predicted that 1) total inorganic N deposition varies predictably along the urban-rural gradient (highest near the city centre), 2) N deposition varies seasonally, with higher fluxes in the winter months when atmospheric stability causes a build-up of N gases in and around the city, and 3) total inorganic N deposition will exceed the critical load of 10-15 kg N ha-1 yr-1 for Mediterranean shrublands, past which negative ecosystem effects have been shown to occur. Estimates of N deposition based on NO2 concentrations within the city suggest that total N deposition ranges from 8-13 kg N ha-1 yr-1 . However, we show that N deposition measured by ion-exchange resin collectors is far less than expected, averaging less than 2 kg N ha-1 yr-1 (range 0.5 - 5.5 kg N ha-1 yr-1 ), and is is dominated by NO3-, suggesting

  10. Synopsis of Nekemias Raf., a segregate genus from Ampelopsis Michx. (Vitaceae) disjunct between eastern/southeastern Asia and eastern North America, with ten new combinations

    PubMed Central

    Wen, Jun; Boggan, John; Nie, Ze-Long

    2014-01-01

    Abstract The genus Nekemias (Vitaceae) was first recognized by Rafinesque in 1838. It has been treated as a synonym of Ampelopsis Michx. Recent phylogenetic studies suggest that Ampelopsis as traditionally delimited is paraphyletic. To maintain the monophyly of each of the genera of Vitaceae, we herein segregate the Ampelopsis sect. Leeaceifoliae lineage from Ampelopsis and recognize these taxa in Nekemias Raf., which has a disjunct distribution in eastern to southeastern Asia and eastern North America. Nomenclatural changes are made for nine species and one variety: Nekemias arborea (L.) J. Wen & Boggan, Nekemias cantoniensis (Hook. & Arn.) J. Wen & Z.L. Nie, Nekemias celebica (Suess.) J. Wen & Boggan, Nekemias chaffanjonii (H. Lév. & Van.) J. Wen & Z.L. Nie, Nekemias gongshanensis (C.L. Li) J. Wen & Z.L. Nie, Nekemias grossedentata (Hand.-Mazz.) J. Wen & Z.L. Nie, Nekemias hypoglauca (Hance) J. Wen & Z.L. Nie, Nekemias megalophylla (Diels & Gilg) J. Wen & Z.L. Nie, Nekemias megalophylla var. jiangxiensis (W.T. Wang) J. Wen & Z.L. Nie, and Nekemias rubifolia (Wall.) J. Wen & Z.L. Nie. A taxonomic key is provided for the genus to facilitate identification. PMID:25383008

  11. Anonymous nuclear markers reveal taxonomic incongruence and long-term disjunction in a cactus species complex with continental-island distribution in South America.

    PubMed

    Perez, Manolo F; Carstens, Bryan C; Rodrigues, Gustavo L; Moraes, Evandro M

    2016-02-01

    The Pilosocereus aurisetus complex consists of eight cactus species with a fragmented distribution associated to xeric enclaves within the Cerrado biome in eastern South America. The phylogeny of these species is incompletely resolved, and this instability complicates evolutionary analyses. Previous analyses based on both plastid and microsatellite markers suggested that this complex contained species with inherent phylogeographic structure, which was attributed to recent diversification and recurring range shifts. However, limitations of the molecular markers used in these analyses prevented some questions from being properly addressed. In order to better understand the relationship among these species and make a preliminary assessment of the genetic structure within them, we developed anonymous nuclear loci from pyrosequencing data of 40 individuals from four species in the P. aurisetus complex. The data obtained from these loci were used to identify genetic clusters within species, and to investigate the phylogenetic relationship among these inferred clusters using a species tree methodology. Coupled with a palaeodistributional modelling, our results reveal a deep phylogenetic and climatic disjunction between two geographic lineages. Our results highlight the importance of sampling more regions from the genome to gain better insights on the evolution of species with an intricate evolutionary history. The methodology used here provides a feasible approach to develop numerous genealogical molecular markers throughout the genome for non-model species. These data provide a more robust hypothesis for the relationship among the lineages of the P. aurisetus complex. PMID:26582125

  12. Catalogue of Bordeaux - southern hemisphere. Stars of the southern hemisphere proposed for the HIPPARCOS mission.

    NASA Astrophysics Data System (ADS)

    Rousseau, J. M.; Périé, J. P.; Gachard, M. T.

    The photographic catalogue of stars in the southern hemisphere from the HIPPARCOS programme has now been completed. This work was performed at the request of the INCA CONSORTIUM using 606 plates taken by the ESO Blue Survey. It contains, with a few rare exceptions, all of the 84323 objects included in the initial programme for the HIPPARCOS mission, without taking into account subsequent choices and priorities, for the zone extending from -17.5 degrees to -90 degrees. It is added to this list: (1) 21265 visible companions with magnitudes ranging from 10 to 16, located less than 30″ from the main object. (2) 12866 additional objects, which are companions that have already been identified, but which are not included in the HIPPARCOS programme, or objects situated in regions left empty by proposers. The complete catalogue therefore includes 118065 objects, mainly stars. The catalogue indicates for each object: the order number (classified by increasing Right Ascension, J2000); the B or V magnitude; the spectral type; the J2000 position; the B1950 position; the individual accuracy, epoch of observation and number of measurements; comments where necessary; LHS, V*, PPM, HIC, SAO, HD, CoD, CPC, CPD, ADS, IDS identifiers if relevant and occasionally 2 other identifiers chosen from amongst 45 standard catalogues (with preference for BD, L, LP, LTT, SRS, CF, UBV, UBV M, BPM, PHL, Ci, SB, GJ, LS...). This catalogue has not been compiled simply for astrometric objectives, but primarily to prepare for the Hipparcos satellite mission. It will shortly be available at the Centre of Astronomic Data in Strasbourg.

  13. Hemispheric asymmetries and the control of motor sequences.

    PubMed

    Serrien, Deborah J; Sovijärvi-Spapé, Michiel M

    2015-04-15

    Sequencing of finger positions reflects a prototype of skilled behaviour. In order to perform sequencing, cognitive control supports the requirements and postural transitions. In this electroencephalography (EEG) study, we evaluate the effects of hand dominance and assess the neural correlates of unimanual and bimanual sequencing in left- and right-handers. The behavioural measurements provided an index of response planning (response time to first key press) and response execution (time between successive key presses, taps/s and percentage of correct responses), whereas the neural dynamics was determined by means of EEG coherence, expressing the functional connectivity between brain areas. Correlations between brain activity and behaviour were calculated for exploring the neural correlates that are functionally relevant for sequencing. Brain-behavioural correlations during response planning and execution revealed the significance of circuitry in the left hemisphere, underlining its significant role in the organisation of goal-directed behaviour. This lateralisation profile was independent of intrinsic constraints (hand dominance) and extrinsic demands (task requirements), suggesting essential higher-order computations in the left hemisphere. Overall, the observations highlight that the left hemisphere is specialised for sequential motor organisation in left- and right-handers, suggesting an endogenous hemispheric asymmetry for compound actions and the representation of skill; processes that can be separated from those that are involved in hand dominance. PMID:25617529

  14. Spanish Heritage and Influence in the Western Hemisphere.

    ERIC Educational Resources Information Center

    San Francisco Unified School District, CA.

    This is a selected bibliography of some good and some outstanding audio-visual educational materials in the library of the Educational Materials Bureau, Audio-Visual Educational Section, that may be considered of particular interest in the study of Spanish heritage and influence in the Western Hemisphere. The bibliography is arranged…

  15. Brain Hemispheres: Administrators Must Look Also to the Right.

    ERIC Educational Resources Information Center

    Dalili, Farid

    In relating brain hemisphere differences to education and educational administration, the author reviews literature on the issue and discusses the concepts involved. For background, he briefly goes over the history of brain and cognition studies and the advent of "split-brain" studies and the "triune" brain theory. Definitions are then given of…

  16. About Hemispheric Differences in the Processing of Temporal Intervals

    ERIC Educational Resources Information Center

    Grondin, S.; Girard, C.

    2005-01-01

    The purpose of the present study was to identify differences between cerebral hemispheres for processing temporal intervals ranging from .9 to 1.4s. The intervals to be judged were marked by series of brief visual signals located in the left or the right visual field. Series of three (two standards and one comparison) or five intervals (four…

  17. Hemisphere-Dependent Holistic Processing of Familiar Faces

    ERIC Educational Resources Information Center

    Ramon, Meike; Rossion, Bruno

    2012-01-01

    In two behavioral experiments involving lateralized stimulus presentation, we tested whether one of the most commonly used measures of holistic face processing--the composite face effect--would be more pronounced for stimuli presented to the right as compared to the left hemisphere. In experiment 1, we investigated the composite face effect in a…

  18. Does Categorical Perception in the Left Hemisphere Depend on Language?

    ERIC Educational Resources Information Center

    Holmes, Kevin J.; Wolff, Phillip

    2012-01-01

    Categorical perception (CP) refers to the influence of category knowledge on perception and is revealed by a superior ability to discriminate items across categories relative to items within a category. In recent years, the finding that CP is lateralized to the left hemisphere in adults has been interpreted as evidence for a kind of CP driven by…

  19. Hemispheric Brain Research: A Breakthrough in Outdoor Education.

    ERIC Educational Resources Information Center

    Staley, Frederick A.

    1980-01-01

    Outdoor education facilitates the use of both cerebral hemispheres. The right side, which is often ignored in traditional education, is the location of intuitive, imaginative, and metaphoric thinking and can be used in conjunction with the left side, the base of logical and analytic thought. (CJ)

  20. Hemispheric Differences in the Recruitment of Semantic Processing Mechanisms

    ERIC Educational Resources Information Center

    Kandhadai, Padmapriya; Federmeier, Kara D.

    2010-01-01

    This study examined how the two cerebral hemispheres recruit semantic processing mechanisms by combining event-related potential measures and visual half-field methods in a word priming paradigm in which semantic strength and predictability were manipulated using lexically associated word pairs. Activation patterns on the late positive complex…

  1. Right Hemisphere Dominance for Emotion Processing in Baboons

    ERIC Educational Resources Information Center

    Wallez, Catherine; Vauclair, Jacques

    2011-01-01

    Asymmetries of emotional facial expressions in humans offer reliable indexes to infer brain lateralization and mostly revealed right hemisphere dominance. Studies concerned with oro-facial asymmetries in nonhuman primates largely showed a left-sided asymmetry in chimpanzees, marmosets and macaques. The presence of asymmetrical oro-facial…

  2. Hemispheric Differences in Bilingual Word and Language Recognition.

    ERIC Educational Resources Information Center

    Roberts, William T.; And Others

    The linguistic role of the right hemisphere in bilingual language processing was examined. Ten right-handed Spanish-English bilinguals were tachistoscopically presented with mixed lists of Spanish and English words to either the right or left visual field and asked to identify the language and the word presented. Five of the subjects identified…

  3. Emotional Valence and Arousal Effects on Memory and Hemispheric Asymmetries

    ERIC Educational Resources Information Center

    Mneimne, Malek; Powers, Alice S.; Walton, Kate E.; Kosson, David S.; Fonda, Samantha; Simonetti, Jessica

    2010-01-01

    This study examined predictions based upon the right hemisphere (RH) model, the valence-arousal model, and a recently proposed integrated model (Killgore & Yurgelun-Todd, 2007) of emotion processing by testing immediate recall and recognition memory for positive, negative, and neutral verbal stimuli among 35 right-handed women. Building upon…

  4. Right Hemispheric Dominance in Processing of Unconscious Negative Emotion

    ERIC Educational Resources Information Center

    Sato, Wataru; Aoki, Satoshi

    2006-01-01

    Right hemispheric dominance in unconscious emotional processing has been suggested, but remains controversial. This issue was investigated using the subliminal affective priming paradigm combined with unilateral visual presentation in 40 normal subjects. In either left or right visual fields, angry facial expressions, happy facial expressions, or…

  5. Clinical Relevance of Discourse Characteristics after Right Hemisphere Brain Damage

    ERIC Educational Resources Information Center

    Blake, Margaret Lehman

    2006-01-01

    Purpose: Discourse characteristics of adults with right hemisphere brain damage are similar to those reported for healthy older adults, prompting the question of whether changes are due to neurological lesions or normal aging processes. The clinical relevance of potential differences across groups was examined through ratings by speech-language…

  6. Gender Differences in Empathy: The Role of the Right Hemisphere

    ERIC Educational Resources Information Center

    Rueckert, Linda; Naybar, Nicolette

    2008-01-01

    The relationship between activation of the right cerebral hemisphere (RH) and empathy was investigated. Twenty-two men and 73 women participated by completing a chimeric face task and empathy questionnaire. For the face task, participants were asked to pick which of the two chimeric faces looked happier. Both men and women were significantly more…

  7. Outpatient Treatment of Dyslexia through Stimulation of the Cerebral Hemispheres.

    ERIC Educational Resources Information Center

    Kappers, E. Jan

    1997-01-01

    Integrated treatment methods of neuropsychological and cognitive origin were evaluated with 80 Dutch children (ages 6-15) with severe dyslexia. Treatment with flash cards, which exercised automatic letter-sound conversions, had a robust and slight effect in preclinical and clinical phases respectively, whereas hemisphere stimulation produced…

  8. What Does the Right Hemisphere Know about Phoneme Categories?

    ERIC Educational Resources Information Center

    Wolmetz, Michael; Poeppel, David; Rapp, Brenda

    2011-01-01

    Innate auditory sensitivities and familiarity with the sounds of language give rise to clear influences of phonemic categories on adult perception of speech. With few exceptions, current models endorse highly left-hemisphere-lateralized mechanisms responsible for the influence of phonemic category on speech perception, based primarily on results…

  9. An Educational Perspective on the Hemispheric Process of the Brain.

    ERIC Educational Resources Information Center

    Languis, Marlin; Kraft, Rosemarie Harter

    This article discusses past research on the hemispheric process of the brain, proposes an educational perspective based on this research, and lists several areas for interdisciplinary study of the relationship between education and the psychobiological dimensions of learning and learning problems. In developing an educational perspective of the…

  10. Characterizing the Influence of Hemispheric Transport on Regional Air Pollution

    EPA Science Inventory

    Expansion of the coupled WRF-CMAQ modeling system to hemispheric scales is pursued to enable the development of a robust modeling framework in which the interactions between atmospheric processes occurring at various spatial and temporal scales can be examined in a consistent man...

  11. Hemispheric Lateralization of Verbal and Spatial Working Memory during Adolescence

    ERIC Educational Resources Information Center

    Nagel, Bonnie J.; Herting, Megan M.; Maxwell, Emily C.; Bruno, Richard; Fair, Damien

    2013-01-01

    Adult functional magnetic resonance imaging (fMRI) literature suggests that a left-right hemispheric dissociation may exist between verbal and spatial working memory (WM), respectively. However, investigation of this type has been obscured by incomparable verbal and spatial WM tasks and/or visual inspection at arbitrary thresholds as means to…

  12. Brain Hemisphericity and Mathematics Achievement of High School Students

    ERIC Educational Resources Information Center

    Fernandez, Sanny F.

    2011-01-01

    This study aimed to find out the brain hemisphericity and mathematics achievement of high school students. The respondents of the study were the 168 first year high school students of Colegio de San Jose, during school year 2010-2011 who were chosen through stratified random sampling. The descriptive and interview methods of research were used in…

  13. Cross-hemispheric dopamine projections have functional significance.

    PubMed

    Fox, Megan E; Mikhailova, Maria A; Bass, Caroline E; Takmakov, Pavel; Gainetdinov, Raul R; Budygin, Evgeny A; Wightman, R Mark

    2016-06-21

    Dopamine signaling occurs on a subsecond timescale, and its dysregulation is implicated in pathologies ranging from drug addiction to Parkinson's disease. Anatomic evidence suggests that some dopamine neurons have cross-hemispheric projections, but the significance of these projections is unknown. Here we report unprecedented interhemispheric communication in the midbrain dopamine system of awake and anesthetized rats. In the anesthetized rats, optogenetic and electrical stimulation of dopamine cells elicited physiologically relevant dopamine release in the contralateral striatum. Contralateral release differed between the dorsal and ventral striatum owing to differential regulation by D2-like receptors. In the freely moving animals, simultaneous bilateral measurements revealed that dopamine release synchronizes between hemispheres and intact, contralateral projections can release dopamine in the midbrain of 6-hydroxydopamine-lesioned rats. These experiments are the first, to our knowledge, to show cross-hemispheric synchronicity in dopamine signaling and support a functional role for contralateral projections. In addition, our data reveal that psychostimulants, such as amphetamine, promote the coupling of dopamine transients between hemispheres. PMID:27298371

  14. Hemispheric Cognitive Style: A Comparison of Three Instruments

    ERIC Educational Resources Information Center

    Genovese, Jeremy E. C.

    2005-01-01

    In this study, the author tested the reliability, concurrent validity, and predictive validity of three hemispheric cognitive style instruments: (a) the Preference Test (PT; R. Zenhausern, 1978), (b) the Polarity Questionnaire (PQ; B. E. Morton, 2002), and (c) the Wagner Preference Inventory II (WAPI II; R. F. Wagner & K. A. Wells, 1985).…

  15. Hemispheric Asymmetry and Pun Comprehension: When Cowboys Have Sore Calves

    ERIC Educational Resources Information Center

    Coulson, Seana; Severens, Els

    2007-01-01

    Event-related potentials (ERPs) were recorded as healthy participants listened to puns such as ''During branding, cowboys have sore calves.'' To assess hemispheric differences in pun comprehension, visually presented probes that were either highly related (COW), moderately related (LEG), or unrelated, were presented in either the left or right…

  16. Radar meteor orbital structure of Southern Hemisphere cometary dust streams

    NASA Technical Reports Server (NTRS)

    Baggaley, W. Jack; Taylor, Andrew D.

    1992-01-01

    The Christchurch, New Zealand meteor orbit radar (AMOR) with its high precision and sensitivity, permits studies of the orbital fine structure of cometary streams. PC generated graphics are presented of data on some Southern Hemisphere Streams. Such data can be related to the formation phase and subsequent dynamical processes of dust streams.

  17. Reading the wrong way with the right hemisphere.

    PubMed

    Waldie, Karen E; Haigh, Charlotte E; Badzakova-Trajkov, Gjurgjica; Buckley, Jude; Kirk, Ian J

    2013-01-01

    Reading is a complex process, drawing on a variety of brain functions in order to link symbols to words and concepts. The three major brain areas linked to reading and phonological analysis include the left temporoparietal region, the left occipitotemporal region and the inferior frontal gyrus. Decreased activation of the left posterior language system in dyslexia is well documented but there is relatively limited attention given to the role of the right hemisphere. The current study investigated differences in right and left hemisphere activation between individuals with dyslexia and non-impaired readers in lexical decision tasks (regular words, irregular words, pseudowords) during functional Magnetic Resonance Imaging (fMRI). Results revealed the expected hypo-activation in the left posterior areas in those with dyslexia but also areas of overactivation in the right hemisphere. During pseudoword decisions, for example, adults with dyslexia showed more right inferior occipital gyrus activation than controls. In general the increased activation of left-hemisphere language areas found in response to both regular and pseudowords was absent in dyslexics. Laterality indices showed that while controls showed left lateralised activation of the temporal lobe during lexical decision making, dyslexic readers showed right activation. Findings will inform theories of reading and will have implications for the design of reading interventions. PMID:24961521

  18. South Hemispheric Teleconnection to Eastern Mediterranean synoptic systems

    NASA Astrophysics Data System (ADS)

    Osetinsky, I.; Alpert, P.

    2009-04-01

    The teleconnections between the Eastern Mediterranean regional climate and large-scaled tropical and midlatitudinal global indices are becoming widely recognized due to the recent publications. We will present the unexpectedly high correlations between the Eastern Mediterranean synoptic system of the Red Sea Trough and global and hemispheric temperature indices. The Red Sea Trough is the pressure pattern originated from the Sudanese Low and stretched over the warm surface of the Red Sea northward, sometimes reaching up to the Western Turkey. We calculated the correlations between the annual number of the Red Sea Trough days over the Eastern Mediterranean region (RST thereafter), and anomalies of the global and northern and southern hemispheric annual temperatures (TG, TNH, TSH, respectively), for 1948-2000. The annual data, both for the RST and for temperatures, were taken unsmoothed. We got the following remarkable correlations: 0.61 between the RST and TG, 0.51 - between RST and TNH, and 0.65 - between RST and TSH. The lower correlation for the Northern Hemisphere (NH), as compared to the Southern Hemisphere (SH), may be explained considering a distribution of continents and oceans. This carries, on the one hand side, a higher NH than SH mankind activity influencing the natural connections, and on the other - an enhanced SH than NH atmospheric circulation.

  19. Adaptive significance of right hemisphere activation in aphasic language comprehension.

    PubMed

    Meltzer, Jed A; Wagage, Suraji; Ryder, Jennifer; Solomon, Beth; Braun, Allen R

    2013-06-01

    Aphasic patients often exhibit increased right hemisphere activity during language tasks. This may represent takeover of function by regions homologous to the left-hemisphere language networks, maladaptive interference, or adaptation of alternate compensatory strategies. To distinguish between these accounts, we tested language comprehension in 25 aphasic patients using an online sentence-picture matching paradigm while measuring brain activation with MEG. Linguistic conditions included semantically irreversible ("The boy is eating the apple") and reversible ("The boy is pushing the girl") sentences at three levels of syntactic complexity. As expected, patients performed well above chance on irreversible sentences, and at chance on reversible sentences of high complexity. Comprehension of reversible non-complex sentences ranged from nearly perfect to chance, and was highly correlated with offline measures of language comprehension. Lesion analysis revealed that comprehension deficits for reversible sentences were predicted by damage to the left temporal lobe. Although aphasic patients activated homologous areas in the right temporal lobe, such activation was not correlated with comprehension performance. Rather, patients with better comprehension exhibited increased activity in dorsal fronto-parietal regions. Correlations between performance and dorsal network activity occurred bilaterally during perception of sentences, and in the right hemisphere during a post-sentence memory delay. These results suggest that effortful reprocessing of perceived sentences in short-term memory can support improved comprehension in aphasia, and that strategic recruitment of alternative networks, rather than homologous takeover, may account for some findings of right hemisphere language activation in aphasia. PMID:23566891

  20. Inferencing Processes after Right Hemisphere Brain Damage: Maintenance of Inferences

    ERIC Educational Resources Information Center

    Blake, Margaret Lehman

    2009-01-01

    Purpose: This study was designed to replicate and extend a previous study of inferencing in which some adults with right hemisphere damage (RHD) generated but did not maintain predictive inferences over time (M. Lehman-Blake & C. Tompkins, 2001). Two hypotheses were tested: (a) inferences were deactivated, and (b) selection of previously generated…

  1. Reading the Wrong Way with the Right Hemisphere

    PubMed Central

    Waldie, Karen E.; Haigh, Charlotte E.; Badzakova-Trajkov, Gjurgjica; Buckley, Jude; Kirk, Ian J.

    2013-01-01

    Reading is a complex process, drawing on a variety of brain functions in order to link symbols to words and concepts. The three major brain areas linked to reading and phonological analysis include the left temporoparietal region, the left occipitotemporal region and the inferior frontal gyrus. Decreased activation of the left posterior language system in dyslexia is well documented but there is relatively limited attention given to the role of the right hemisphere. The current study investigated differences in right and left hemisphere activation between individuals with dyslexia and non-impaired readers in lexical decision tasks (regular words, irregular words, pseudowords) during functional Magnetic Resonance Imaging (fMRI). Results revealed the expected hypo-activation in the left posterior areas in those with dyslexia but also areas of overactivation in the right hemisphere. During pseudoword decisions, for example, adults with dyslexia showed more right inferior occipital gyrus activation than controls. In general the increased activation of left-hemisphere language areas found in response to both regular and pseudowords was absent in dyslexics. Laterality indices showed that while controls showed left lateralised activation of the temporal lobe during lexical decision making, dyslexic readers showed right activation. Findings will inform theories of reading and will have implications for the design of reading interventions. PMID:24961521

  2. Northern Hemisphere control of deglacial vegetation changes in the Rufiji uplands (Tanzania)

    NASA Astrophysics Data System (ADS)

    Bouimetarhan, I.; Dupont, L.; Kuhlmann, H.; Patzold, J.; Prange, M.; Schefuss, E.; Zonneveld, K.

    2015-05-01

    In tropical eastern Africa, vegetation distribution is largely controlled by regional hydrology, which has varied over the past 20 000 years. Therefore, accurate reconstructions of past vegetation and hydrological changes are crucial for a better understanding of climate variability in the tropical southeastern African region. We present high-resolution pollen records from a marine sediment core recovered offshore of the Rufiji River delta. Our data document significant shifts in pollen assemblages during the last deglaciation, identifying, through changes in both upland and lowland vegetation, specific responses of plant communities to atmospheric (precipitation) and coastal (coastal dynamics and sea-level changes) alterations. Specifically, arid conditions reflected by a maximum pollen representation of dry and open vegetation occurred during the Northern Hemisphere cold Heinrich event 1 (H1), suggesting that the expansion of drier upland vegetation was synchronous with cold Northern Hemisphere conditions. This arid period is followed by an interval in which forest and humid woodlands expanded, indicating a hydrologic shift towards more humid conditions. Droughts during H1 and the shift to humid conditions around 14.8 kyr BP in the uplands are consistent with latitudinal shifts of the intertropical convergence zone (ITCZ) driven by high-latitude Northern Hemisphere climatic fluctuations. Additionally, our results show that the lowland vegetation, consisting of well-developed salt marshes and mangroves in a successional pattern typical for vegetation occurring in intertidal habitats, has responded mainly to local coastal dynamics related to marine inundation frequencies and soil salinity in the Rufiji Delta as well as to the local moisture availability. Lowland vegetation shows a substantial expansion of mangrove trees after ~ 14.8 kyr BP, suggesting an increased moisture availability and river runoff in the coastal area. The results of this study highlight the

  3. Inter-hemispheric plasticity in patients with median nerve injury.

    PubMed

    Fornander, Lotta; Nyman, Torbjörn; Hansson, Thomas; Brismar, Tom; Engström, Maria

    2016-08-15

    Peripheral nerve injuries result in reorganization within the contralateral hemisphere. Furthermore, recent animal and human studies have suggested that the plastic changes in response to peripheral nerve injury also include several areas of the ipsilateral hemisphere. The objective of this study was to map the inter-hemispheric plasticity in response to median nerve injury, to investigate normal differences in contra- and ipsilateral activation, and to study the impact of event-related or blocked functional magnetic resonance imaging (fMRI) design on ipsilateral activation. Four patients with median nerve injury at the wrist (injured and epineurally sutured >2 years earlier) and ten healthy volunteers were included. 3T fMRI was used to map the hemodynamic response to brain activity during tactile stimulation of the fingers, and a laterality index (LI) was calculated. Stimulation of Digits II-III of the injured hand resulted in a reduction in contralateral activation in the somatosensory area SI. Patients had a lower LI (0.21±0.15) compared to healthy controls (0.60±0.26) indicating greater ipsilateral activation of the primary somatosensory cortex. The spatial dispersion of the coordinates for areas SI and SII was larger in the ipsilateral than in the contralateral hemisphere in the healthy controls, and was increased in the contralateral hemisphere of the patients compared to the healthy controls. There was no difference in LI between the event-related and blocked paradigms. In conclusion, patients with median nerve injury have increased ipsilateral SI area activation, and spatially more dispersed contralateral SI activation during tactile stimulation of their injured hand. In normal subjects ipsilateral activation has larger spatial distribution than the contralateral. Previous findings in patients performed with the blocked fMRI paradigm were confirmed. The increase in ipsilateral SI activation may be due to an interhemispheric disinhibition associated with

  4. A multidisciplinary overview of intoxicating snuff rituals in the western hemisphere.

    PubMed

    de Smet, P A

    1985-03-01

    Part one of the paper discusses ethnobotanical, chemical and general pharmacological aspects of intoxicating snuff rituals in the western hemisphere. Four categories of ritual snuff ingredients arise from this multidisciplinary approach: It is well established that the plant contains one or more psychoactive principles and the Indian use of the plant as a ritual snuff ingredient is confirmed or quite probable: Anadenanthera, Erythroxylum, Nicotiana, Virola; It is well established that the plant contains one or more psychoactive principles, but the Indian use of the plant as a ritual snuff ingredient is not well recorded or even unlikely: Banisteriopsis, Cannabis, Datura, Ilex guayusa; The Indian use of the plant as a ritual snuff ingredient is confirmed or quite probable, but it is not well established that the plant contains one or more psychoactive principles: Justicia pectoralis, Pagamea macrophylla, Tanaecium nocturnum; The Indian use of the plant as a ritual snuff ingredient is not well recorded, and it is not well established that the plant contains one or more psychoactive principles: Acorus calamus, Capsicum, Macquira sclerophylla, Piper interitum. Part two of the paper discusses the nasal pharmacokinetics and efficacy of possible ritual snuff constituents. The literature yields convincing clinical evidence that atropine, cocaine, nicotine and scopolamine are effective following nasal application, but experimental confirmation of the efficacy of nasal tryptamine alkaloids is still awaited. In self-experiments, 6.4 mg/kg of caffeine produced substantial plasma levels via the nasal route, but 0.5 mg/kg of harmine did not produce measurable plasma levels, when taken as a nasal powder. Without additional experiments, it is difficult to give a definite explanation for this negative result. PMID:3887041

  5. Neuropragmatics: Extralinguistic Pragmatic Ability is Better Preserved in Left-Hemisphere-Damaged Patients than in Right-Hemisphere-Damaged Patients

    ERIC Educational Resources Information Center

    Cutica, Ilaria; Bucciarelli, Monica; Bara, Bruno G.

    2006-01-01

    The aim of the present study is to compare the pragmatic ability of right- and left-hemisphere-damaged patients excluding the possible interference of linguistic deficits. To this aim, we study extralinguistic communication, that is communication performed only through gestures. The Cognitive Pragmatics Theory provides the theoretical framework:…

  6. Right hemisphere dominance for language in a woman with schizophrenia and a porencephalic cyst of the left hemisphere.

    PubMed

    de Oliveira-Souza, Ricardo; Monteiro, Myriam; Pacheco, Paula; Tovar-Moll, Fernanda; Mattos, Paulo; Moll, Jorge; Nazar, Bruno Palazzo

    2016-06-01

    A large left hemisphere porencephalic cyst was incidentally found in a 48-year-old woman (MS) with a Diagnostic and Statistical Manual (DSM)-5 diagnosis of schizophrenia. The encephaloclastic characteristics of the cyst indicated that it was acquired between the 22nd and 24th gestational weeks, after the major waves of neuronal migration had tapered off. The cyst destroyed the left temporal and occipital lobes, and the inferior parietal lobule. Surprisingly, MS had no evidence of aphasia, alexia, agraphia, or ideational apraxia; in contrast, cognitive functions dependent on the integrity of the right hemisphere were severely impaired. To test the hypothesis that the development of language in MS took place at the expense of functions that are normally carried out by the right hemisphere, we investigated MS's correlates of oral comprehension with fMRI as a proxy for auditory comprehension and other cognitive functions strongly lateralized to the posterior left hemisphere, such as ideational praxis and reading. Comprehension of spoken language engaged the homologous of Wernicke's area in the right planum temporale. Porencephaly may represent a natural model of neuroplasticity supervening at predictable epochs of prenatal development. PMID:27283036

  7. The left hemisphere learns what is right: Hemispatial reward learning depends on reinforcement learning processes in the contralateral hemisphere.

    PubMed

    Aberg, Kristoffer Carl; Doell, Kimberly Crystal; Schwartz, Sophie

    2016-08-01

    Orienting biases refer to consistent, trait-like direction of attention or locomotion toward one side of space. Recent studies suggest that such hemispatial biases may determine how well people memorize information presented in the left or right hemifield. Moreover, lesion studies indicate that learning rewarded stimuli in one hemispace depends on the integrity of the contralateral striatum. However, the exact neural and computational mechanisms underlying the influence of individual orienting biases on reward learning remain unclear. Because reward-based behavioural adaptation depends on the dopaminergic system and prediction error (PE) encoding in the ventral striatum, we hypothesized that hemispheric asymmetries in dopamine (DA) function may determine individual spatial biases in reward learning. To test this prediction, we acquired fMRI in 33 healthy human participants while they performed a lateralized reward task. Learning differences between hemispaces were assessed by presenting stimuli, assigned to different reward probabilities, to the left or right of central fixation, i.e. presented in the left or right visual hemifield. Hemispheric differences in DA function were estimated through differential fMRI responses to positive vs. negative feedback in the left vs. right ventral striatum, and a computational approach was used to identify the neural correlates of PEs. Our results show that spatial biases favoring reward learning in the right (vs. left) hemifield were associated with increased reward responses in the left hemisphere and relatively better neural encoding of PEs for stimuli presented in the right (vs. left) hemifield. These findings demonstrate that trait-like spatial biases implicate hemisphere-specific learning mechanisms, with individual differences between hemispheres contributing to reinforcing spatial biases. PMID:27221149

  8. Spectral bidirectional and hemispherical reflectance characteristics of selected sites in the Streletskaya steppe

    NASA Technical Reports Server (NTRS)

    Eck, Thomas F.; Deering, Donald W.

    1992-01-01

    Measurements of plant canopy bidirectional reflectance made by the PARABOLA (portable apparatus for rapid acquisition of bidirectional observations of the land and atmosphere) instrument in three spectral bands are analyzed for steppe grassland sites of differing productivity levels. The variation of spectral reflectance and the normalized difference vegetation index in the solar principal plane is presented. Comparisons are made with PARABOLA measurements from selected first ISLSCP field experiment (FIFE) grassland sites in the Konza prairie, Kansas. The Streletskaya steppe sites showed no strong hot spot reflectance, while this effect was present in some FIFE sites but absent in others. The hot spot effect seems to be dependent on canopy geometry and background reflectance characteristics of these sites. Spectral hemispherical reflectance was computed from the angular integration of the bidirectional measurements for the steppe sites. Total shortwave albedo was estimated from these hemispherical reflectance measurements and compared to albedo measured by pyranometers. The albedo estimates from PARABOLA were found to be approximately 12-17 percent higher than the pyranometer measurements.

  9. Phylogeny and biogeography of exacum (gentianaceae): a disjunctive distribution in the Indian ocean basin resulted from long distance dispersal and extensive radiation.

    PubMed

    Yuan, Yong-Ming; Wohlhauser, Sébastien; Möller, Michael; Klackenberg, Jens; Callmander, Martin; Küpfer, Philippe

    2005-02-01

    Disjunctive distributions across paleotropical regions in the Indian Ocean Basin (IOB) often invoke dispersal/vicariance debates. Exacum (Gentianaceae, tribe Exaceae) species are spread around the IOB, in Africa, Madagascar, Socotra, the Arabian peninsula, Sri Lanka, India, the Himalayas, mainland Southeast Asia including southern China and Malaysia, and northern Australia. The distribution of this genus was suggested to be a typical example of vicariance resulting from the breakup of the Gondwanan supercontinent. The molecular phylogeny of Exacum is in principle congruent with morphological conclusions and shows a pattern that resembles a vicariance scenario with rapid divergence among lineages, but our molecular dating analysis demonstrates that the radiation is too recent to be associated with the Gondwanan continental breakup. We used our dating analysis to test the results of DIVA and found that the program predicted impossible vicariance events. Ancestral area reconstruction suggests that Exacum originated in Madagascar, and divergence dating suggests its origin was not before the Eocene. The Madagascan progenitor, the most recent common ancestor of Exacum, colonized Sri Lanka and southern India via long-distance dispersals. This colonizer underwent an extensive range expansion and spread to Socotra-Arabia, northern India, and mainland Southeast Asia in the northern IOB when it was warm and humid in these regions. This widespread common ancestor retreated subsequently from most parts of these regions and survived in isolation in Socotra-Arabia, southern India-Sri Lanka, and perhaps mainland Southeast Asia, possibly as a consequence of drastic climatic changes, particularly the spreading drought during the Neogene. Secondary diversification from these surviving centers and Madagascar resulted in the extant main lineages of the genus. The vicariance-like pattern shown by the phylogeny appears to have resulted from long-distance dispersals followed by extensive

  10. Characterization of O2 evolution by a wheat photosystem II reaction center complex isolated by a simplified method: disjunction of secondary acceptor quinone and enhanced Ca2+ demand.

    PubMed

    Ikeuchi, M; Inoue, Y

    1986-05-15

    An O2-evolving photosystem II (PSII) reaction center complex was prepared from wheat by a simple method consisting of octylglucoside solubilization of Triton PSII particles followed by one-step sucrose density gradient centrifugation. The complex contained six species of proteins including the 33-kDa extrinsic protein with the same relative abundance as in the original PSII particles, one cytochrome b559, 4 Mn, and about 40 chlorophyll (Chl) per O2-evolving unit, and evolved O2 at a high rate of 1400-1700 mumol O2/mg Chl/h. O2 evolution by the complex was dependent on acceptor species, showing a hierarchy, ferricyanide greater than dichlorobenzoquinone greater than phenylbenzoquinone greater than dimethylbenzoquinone greater than duroquinone, and insensitive to DCMU, indicative of disjunction of the secondary quinone acceptor of PSII from the electron transport pathway. O2 evolution also showed a marked dependence on Cl- and Ca2+: about 10-fold acceleration by Cl- and an additional 2- to 3-fold by Ca2+. Comparison of the dissociation constants for Cl- and Ca2+ between the complex and NaCl-washed PSII particles revealed that octylglucoside treatment gives rise to a new Ca2+-sensitive site by removal of some unknown factor(s) other than the extrinsic 22- and 16-kDa proteins, while it preserves the Cl(-)-sensitive site as native as in NaCl-washed PSII particles. Analysis of the relationship between Cl- demand and Ca2+ demand revealed that Ca2+ absence noncompetitively inhibits the Cl(-)-supported O2 evolution, indicative of the independence of the binding site of these two factors. PMID:3518636

  11. 75 FR 5287 - Federal Advisory Committee; Western Hemisphere Institute for Security Cooperation Board of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-02

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF DEFENSE Office of the Secretary Federal Advisory Committee; Western Hemisphere Institute for Security Cooperation... Hemisphere Institute for Security Cooperation Board of Visitors (hereafter referred to as the Board)....

  12. Deep Genetic Divergence between Disjunct Refugia in the Arctic-Alpine King’s Crown, Rhodiola integrifolia (Crassulaceae)

    PubMed Central

    DeChaine, Eric G.; Forester, Brenna R.; Schaefer, Hanno; Davis, Charles C.

    2013-01-01

    Despite the strength of climatic variability at high latitudes and upper elevations, we still do not fully understand how plants in North America that are distributed between Arctic and alpine areas responded to the environmental changes of the Quaternary. To address this question, we set out to resolve the evolutionary history of the King’s Crown, Rhodiola integrifolia using multi-locus population genetic and phylogenetic analyses in combination with ecological niche modeling. Our population genetic analyses of multiple anonymous nuclear loci revealed two major clades within R. integrifolia that diverged from each other ~ 700 kya: one occurring in Beringia to the north (including members of subspecies leedyi and part of subspecies integrifolia), and the other restricted to the Southern Rocky Mountain refugium in the south (including individuals of subspecies neomexicana and part of subspecies integrifolia). Ecological niche models corroborate our hypothesized locations of refugial areas inferred from our phylogeographic analyses and revealed some environmental differences between the regions inhabited by its two subclades. Our study underscores the role of geographic isolation in promoting genetic divergence and the evolution of endemic subspecies in R. integrifolia. Furthermore, our phylogenetic analyses of the plastid spacer region trnL-F demonstrate that among the native North American species, R. integrifolia and R. rhodantha are more closely related to one another than either is to R. rosea. An understanding of these historic processes lies at the heart of making informed management decisions regarding this and other Arctic-alpine species of concern in this increasingly threatened biome. PMID:24282505

  13. Agents with left and right dominant hemispheres and quantum statistics

    NASA Astrophysics Data System (ADS)

    Ezhov, Alexandr A.; Khrennikov, Andrei Yu.

    2005-01-01

    We present a multiagent model illustrating the emergence of two different quantum statistics, Bose-Einstein and Fermi-Dirac, in a friendly population of individuals with the right-brain dominance and in a competitive population of individuals with the left-brain hemisphere dominance, correspondingly. Doing so, we adduce the arguments that Lefebvre’s “algebra of conscience” can be used in a natural way to describe decision-making strategies of agents simulating people with different brain dominance. One can suggest that the emergence of the two principal statistical distributions is able to illustrate different types of society organization and also to be used in order to simulate market phenomena and psychic disorders, when a switching of hemisphere dominance is involved.

  14. First Scientific Results from the VISTA Hemisphere Survey (VHS)

    NASA Astrophysics Data System (ADS)

    McMahon, R. G.; Banerji, M.; Gonzalez, E.; Koposov, S. E.; Bejar, V. J.; Lodieu, N.; Rebolo, R.; VHS Collaboration

    2013-12-01

    The first Galactic and extragalactic results from the VISTA Hemisphere Survey (VHS) are presented. The aim of the VHS is to carry out a near-infrared survey which, when combined with other VISTA public surveys, will result in coverage of the whole southern celestial hemisphere (~20 000 square degrees) to a depth 30 times fainter than the Two Micron All Sky Survey in at least two wavebands (J and Ks). The VHS vision includes a deep optical survey over the same area and this is now being realised with the VST surveys and the Dark Energy Survey, which has recently started. A summary of the survey progress is presented, with some follow-up results on low-mass stars and high-redshift quasars.

  15. A [111]-Cut Si Hemisphere Two-Photon Response Photodetector

    NASA Astrophysics Data System (ADS)

    Liu, Xiu-Huan; Chen, Zhan-Guo; Jia, Gang; Wang, Hai-Yan; Gao, Yan-Jun; Li, Yi

    2011-11-01

    Properties of two-photon response in a [111]-cut nearly-intrinsic Si hemisphere photodetector are studied. The measured photocurrent of the photodetector responding to the 1.32μm continuous wave laser shows a quadratic dependence on the coupled optical power and is saturated with the bias voltage. Also, the photocurrent is independent of polarization. Such properties are in good agreement with the theory of two-photon absorption. The isotropic photocurrent generated from the [111]-cut Si hemisphere is compared to the anisotropic one induced in the [110]-cut Si sample and the ratio of χxxxx/χxxyy for silicon performing at 1.32 μm is calculated to be 2.4 via the fitted function of the anisotropic photocurrent from the [110]-cut sample.

  16. On the lack of southern hemisphere polar mesosphere summer echoes

    NASA Astrophysics Data System (ADS)

    Balsley, B. B.; Woodman, R. F.; Sarango, M.; RodríGuez, R.; Urbina, J.; Ragaini, E.; Carey, J.; Huaman, M.; Giraldez, A.

    1995-06-01

    We report VHF radar observations of the southern high-latitude mesopause region using wind profilers that were installed recently on King George Island, Antarctica, and Ushuaia, Argentina. Briefly, our observations, which were made during January and February 1993, show almost no evidence of so-called polar mesosphere summer echoes, or PMSE. Since these echoes are a predominant feature of the northern high-latitude mesosphere in summer, their absence in the southern hemisphere is both surprising and intriguing. In this paper we present evidence demonstrating the virtual absence of the echoes and demonstrate that our systems were capable of detecting them had they been present. We also outline some of the consequences of this intriguing result, which are supported by observed hemispheric differences in polar mesospheric clouds, mesospheric temperatures, upper atmospheric gravity wave activity, and mean circulation patterns.

  17. Hemispherical Anisotropic Patterns of the Earth's Inner Core

    NASA Astrophysics Data System (ADS)

    Mattesini, M.; Belonoshko, A. B.; Buforn, E.; Ramirez, M.; Simak, S. I.; Udias, A.; Mao, H.; Ahuja, R.

    2010-12-01

    It has been shown that the Earth's inner core has an axisymmetric anisotropic structure with seismic waves travelling ˜3% faster along polar paths than along equatorial directions. However, hemispherical anisotropic patterns of solid Earth's core are rather complex, and the commonly used hexagonal-close-packed (hcp) iron phase might be insufficient to account for seismological observations. We show that the data we collected are in good agreement with the presence of two anisotropically specular east and west core hemispheres. The detected travel-time anomalies can only be disclosed by a lattice preferred orientation of a body-centered-cubic iron aggregate (bcc), having a fraction of their [111] crystal axes parallel to the Earth's rotation axis. This is a compelling evidence for the presence of a body-centered-cubic Fe phase at the top 100 km of the Earth's inner core.

  18. Left hemispheric advantage for numerical abilities in the bottlenose dolphin.

    PubMed

    Kilian, Annette; von Fersen, Lorenzo; Güntürkün, Onur

    2005-02-28

    In a two-choice discrimination paradigm, a bottlenose dolphin discriminated relational dimensions between visual numerosity stimuli under monocular viewing conditions. After prior binocular acquisition of the task, two monocular test series with different number stimuli were conducted. In accordance with recent studies on visual lateralization in the bottlenose dolphin, our results revealed an overall advantage of the right visual field. Due to the complete decussation of the optic nerve fibers, this suggests a specialization of the left hemisphere for analysing relational features between stimuli as required in tests for numerical abilities. These processes are typically right hemisphere-based in other mammals (including humans) and birds. The present data provide further evidence for a general right visual field advantage in bottlenose dolphins for visual information processing. It is thus assumed that dolphins possess a unique functional architecture of their cerebral asymmetries. PMID:15686828

  19. Left face matching bias: right hemisphere dominance or scanning habits?

    PubMed

    Megreya, Ahmed M; Havard, Catriona

    2011-01-01

    A large body of work report a leftward bias in face processing. However, it is not clear whether this leftward bias purely reflects the dominance of the right hemisphere or is influenced by scanning habits developed by reading directions. Here, we report two experiments examining how well native readers of right to left Arabic scripts (Egyptians) could match (for identity) a target face that appeared with a companion to a line-up of 10 faces. There was a significant advantage for matching faces that appeared on the left. However, Experiment 2 found that the magnitude of this left face matching bias was almost three times weaker than the magnitude of the leftward bias shown by native readers of left to right English scripts (British). Accordingly, we suggest that the right hemisphere dominance for face processing underlies the leftward face perception bias, but with the interaction of scanning habits. PMID:21204307

  20. Semantic-pragmatic disorder: a right hemisphere syndrome?

    PubMed

    Shields, J

    1991-12-01

    Following right hemisphere lesions, adults' speech can become copious and inappropriate, with abnormal prosody, and they may be unable to comprehend metaphor or humour. Their symptoms resemble those of children with semantic-pragmatic language disorder, who use fluent, grammatically complex language, but with poor sensitivity to the communicative situation. The hyperlexia found in some of these children reflects an underlying cognitive problem in integrating semantic information with knowledge of the world. Both groups of patients fail comprehend inferential meaning or to make use of paralinguistic features. It is hypothesised that the disorders of communication and cognition found in semantic-pragmatic language disorder may be linked to right hemisphere dysfunction, but this has yet to be confirmed by research. PMID:1814422

  1. Hemispherical anisotropic patterns of the Earth’s inner core

    PubMed Central

    Mattesini, Maurizio

    2010-01-01

    It has been shown that the Earth’s inner core has an axisymmetric anisotropic structure with seismic waves traveling ∼3% faster along polar paths than along equatorial directions. Hemispherical anisotropic patterns of the solid Earth’s core are rather complex, and the commonly used hexagonal-close-packed iron phase might be insufficient to account for seismological observations. We show that the data we collected are in good agreement with the presence of two anisotropically specular east and west core hemispheres. The detected travel-time anomalies can only be disclosed by a lattice-preferred orientation of a body-centered-cubic iron aggregate, having a fraction of their [111] crystal axes parallel to the Earth’s rotation axis. This is compelling evidence for the presence of a body-centered-cubic Fe phase at the top of the Earth’s inner core. PMID:20457937

  2. Film Boiling on Downward Quenching Hemisphere of Varying Sizes

    SciTech Connect

    Chan S. Kim; Kune Y. Suh; Joy L. Rempe; Fan-Bill Cheung; Sang B. Kim

    2004-04-01

    Film boiling heat transfer coefficients for a downward-facing hemispherical surface are measured from the quenching tests in DELTA (Downward-boiling Experimental Laminar Transition Apparatus). Two test sections are made of copper to maintain low Biot numbers. The outer diameters of the hemispheres are 120 mm and 294 mm, respectively. The thickness of all the test sections is 30 mm. The effect of diameter on film boiling heat transfer is quantified utilizing results obtained from the test sections. The measured data are compared with the numerical predictions from laminar film boiling analysis. The measured heat transfer coefficients are found to be greater than those predicted by the conventional laminar flow theory on account of the interfacial wavy motion incurred by the Helmholtz instability. Incorporation of the wavy motion model considerably improves the agreement between the experimental and numerical results in terms of heat transfer coefficient. In addition, the interfacial wavy motion and the quenching process are visualized through a digital camera.

  3. Hemispherical anisotropic patterns of the Earth's inner core.

    PubMed

    Mattesini, Maurizio; Belonoshko, Anatoly B; Buforn, Elisa; Ramírez, María; Simak, Sergei I; Udías, Agustín; Mao, Ho-Kwang; Ahuja, Rajeev

    2010-05-25

    It has been shown that the Earth's inner core has an axisymmetric anisotropic structure with seismic waves traveling approximately 3% faster along polar paths than along equatorial directions. Hemispherical anisotropic patterns of the solid Earth's core are rather complex, and the commonly used hexagonal-close-packed iron phase might be insufficient to account for seismological observations. We show that the data we collected are in good agreement with the presence of two anisotropically specular east and west core hemispheres. The detected travel-time anomalies can only be disclosed by a lattice-preferred orientation of a body-centered-cubic iron aggregate, having a fraction of their [111] crystal axes parallel to the Earth's rotation axis. This is compelling evidence for the presence of a body-centered-cubic Fe phase at the top of the Earth's inner core. PMID:20457937

  4. Differential diagnosis of cerebral hemispheric pathology: multimodal approach.

    PubMed

    Moritani, T; Smoker, W R K; Lee, H K; Sato, Y

    2011-06-01

    This article gives a comprehensive review and illustrations of the imaging features of various pathological conditions and clinical syndromes associated with cerebral hemispheric involvement. The various conditions are described and defined to provide a basis for the differential diagnostics. The hypotheses relating to the pathology of the various syndromes are discussed with special emphasis on excitotoxic mechanisms for explaining the subsequent cerebral hemiatrophy. PMID:21528369

  5. The effects of orography on midlatitude Northern Hemisphere dry climates

    SciTech Connect

    Broccoli, A.J.; Manabe, S. )

    1992-11-01

    The role of mountains in maintaining extensive midlatitude arid regions in the Northern Hemisphere was studied utilizing simulations from the GFDL GMC with and without orography. In the integration with mountains, dry climates were simulated over the interior of North America and central Asia, in good agreement with the observed climate. The results from these experiments indicate that midlatitude dryness is due largely to the existence of orography. 38 refs.

  6. Task specific inter-hemispheric coupling in human subthalamic nuclei

    PubMed Central

    Darvas, Felix; Hebb, Adam O.

    2014-01-01

    Cortical networks and quantitative measures of connectivity are integral to the study of brain function. Despite lack of direct connections between left and right subthalamic nuclei (STN), there are apparent physiological connections. During clinical examination of patients with Parkinson’s disease (PD), this connectivity is exploited to enhance signs of PD, yet our understanding of this connectivity is limited. We hypothesized that movement leads to synchronization of neural oscillations in bilateral STN, and we implemented phase coherence, a measure of phase-locking between cortical sites in a narrow frequency band, to demonstrate this synchronization. We analyzed task specific phase synchronization and causality between left and right STN local field potentials (LFPs) recorded from both hemispheres simultaneously during a cued movement task in four subjects with PD who underwent Deep Brain Stimulation (DBS) surgery. We used a data driven approach to determine inter-hemispheric channel pairs and frequencies with a task specific increase in phase locking.We found significant phase locking between hemispheres in alpha frequency (8–12 Hz) in all subjects concurrent with movement of either hand. In all subjects, phase synchronization increased over baseline upon or prior to hand movement onset and lasted until the motion ceased. Left and right hand movement showed similar patterns. Granger causality (GC) at the phase-locking frequencies between synchronized electrodes revealed a unidirectional causality from right to left STN regardless of which side was moved.Phase synchronization across hemispheres between basal ganglia supports existence of a bilateral network having lateralized regions of specialization for motor processing. Our results suggest this bilateral network is activated by a unilateral motor program. Understanding phase synchronization in natural brain functions is critical to development of future DBS systems that augment goal directed behavioral

  7. Entire Western Hemisphere visible from Apollo 8 spacecraft

    NASA Technical Reports Server (NTRS)

    1968-01-01

    A striking view from the Apollo 8 spacecraft showing nearly the entire Western Hemisphere, from the mouth of the St. Lawrence River, including nearby Newfoundland, extending to Tierra del Fuego at the southern tip of South America. Central America is clearly outlined. Nearly all of South America is covered by clouds, except the high Andes Mountain chain along the west coast. A small portion of the bulge of west Africa shows along the sunset terminator.

  8. Northern Hemisphere Slopes from Mars Orbiter Laser Altimeter

    NASA Astrophysics Data System (ADS)

    Aharonson, O.; Zuber, M. T.

    1998-12-01

    Slopes, slope distributions, and macroscale surface roughness in the northern hemisphere of Mars have been measured from topographic profiles collected by the Mars Orbiter Laser Altimeter (MOLA) in the capture orbit, aerobraking hiatus and Science Phasing Orbit phases of the Mars Global Surveyor mission. The distribution function of slopes indicates that portions of the Martian surface fall into statistically distinct categories, distinguished by the histograms of both point-to-point slopes and of longer wavelength (10 and 100 km) slopes. Roughness correlates with elevation such that low regions tend to exhibit low roughness. Areas such as southern hemisphere highlands, dichotomy boundary terrains, and northern hemisphere lowlands all posses unique slope distribution signatures. The slope distribution within the Amazonis Planitia region, particularly member 3 of the Arcadia formation, displays an unusually smooth character. This region of anomalously low thermal inertia and low radar backscatter cross-section exhibits an rms variation in topography of <2 m over a 100-km baseline. Previous interpretations have suggested that this area is composed of accumulation of fine dust. Statistical comparison with other planetary surfaces of varying origin indicates that Amazonis most closely resembles in its smoothness the heavily sedimented surfaces on the Earth, i.e. oceanic abyssal plains and basins characterized by fluvial deposition. The smoothest measured volcanic surfaces as measured by altimetry on the Moon, Venus, and Mars are all significantly rougher than Amazonis. Saharan sand sheets are rougher by a factor of about three. Other regions in the Martian northern hemisphere that exhibit clear evidence of aeolian deposition are rougher than Amazonis as well.

  9. Hemispheric Symmetries of Plio-Pleistocene Surface Ocean Conditions: Insights from Southern Hemisphere ODP Sites 1125 and 1088

    NASA Astrophysics Data System (ADS)

    Lawrence, K. T.; Peterson, L.; Kelly, C.; Miller, H.; Seidenstein, J.

    2013-12-01

    For decades, most studies of Plio-Pleistocene climate and of the transition from the warmth of the Pliocene to the colder and more variable conditions of the Pleistocene have focused solely on northern hemisphere climate processes and responses. Here, we explore the southern hemisphere response to this major climate transition by documenting ocean surface conditions at Ocean Drilling Program Sites 1125 (42οS, 178οW, 1360m) and 1088 (40οS, 15οE, 2082m) through the Plio-Pleistocene. Secular trends in alkenone-derived sea surface temperature (SST) records indicate that these mid-latitude southern hemisphere sites cooled ~3-4οC over the past 3 Myrs, a magnitude comparable to sites located at similar latitudes in both the North Atlantic and North Pacific. This observation suggests that contraction of the low latitude warm pool was hemispherically symmetric. Our highly resolved (3 kyr resolution) Site 1125 SST record bears considerable structural similarity to SST records from nearby site 1123 (42οS,171οW) as well as sites 846 (3οS, 91οW) in the eastern equatorial Pacific and U1313 (41οN, 33οW) in the North Atlantic. Most of these SST records are dominated by 100k power and contain strong secondary 41k peaks throughout the past 3 million years. North Atlantic site U1313 is the exception, mirroring the shift in dominant periodicity from 41k to 100k associated with the mid-Pleistocene transition, that has long been observed in benthic oxygen isotope records. Finally, in southern hemisphere SST records as well as at site U1313 from the north Atlantic we observe weak precessional power that is not evident in benthic oxygen isotope record. These results suggest a fairly hemispherically-coordinated response of ocean surface temperature to changing global climate conditions during the Plio-Pleistocene in terms of both secular trends and dominant orbital frequencies.

  10. Post-Stroke Longitudinal Alterations of Inter-Hemispheric Correlation and Hemispheric Dominance in Mouse Pre-Motor Cortex

    PubMed Central

    Panarese, Alessandro; Alia, Claudia; Micera, Silvestro; Caleo, Matteo; Di Garbo, Angelo

    2016-01-01

    Purpose Limited restoration of function is known to occur spontaneously after an ischemic injury to the primary motor cortex. Evidence suggests that Pre-Motor Areas (PMAs) may “take over” control of the disrupted functions. However, little is known about functional reorganizations in PMAs. Forelimb movements in mice can be driven by two cortical regions, Caudal and Rostral Forelimb Areas (CFA and RFA), generally accepted as primary motor and pre-motor cortex, respectively. Here, we examined longitudinal changes in functional coupling between the two RFAs following unilateral photothrombotic stroke in CFA (mm from Bregma: +0.5 anterior, +1.25 lateral). Methods Local field potentials (LFPs) were recorded from the RFAs of both hemispheres in freely moving injured and naïve mice. Neural signals were acquired at 9, 16 and 23 days after surgery (sub-acute period in stroke animals) through one bipolar electrode per hemisphere placed in the center of RFA, with a ground screw over the occipital bone. LFPs were pre-processed through an efficient method of artifact removal and analysed through: spectral,cross-correlation, mutual information and Granger causality analysis. Results Spectral analysis demonstrated an early decrease (day 9) in the alpha band power in both the RFAs. In the late sub-acute period (days 16 and 23), inter-hemispheric functional coupling was reduced in ischemic animals, as shown by a decrease in the cross-correlation and mutual information measures. Within the gamma and delta bands, correlation measures were already reduced at day 9. Granger analysis, used as a measure of the symmetry of the inter-hemispheric causal connectivity, showed a less balanced activity in the two RFAs after stroke, with more frequent oscillations of hemispheric dominance. Conclusions These results indicate robust electrophysiological changes in PMAs after stroke. Specifically, we found alterations in transcallosal connectivity, with reduced inter-hemispheric functional

  11. Why do planetary wave number one and the ozone transport vary annually in the Northern Hemisphere and semiannually in the Southern Hemisphere

    NASA Technical Reports Server (NTRS)

    Geller, M. A.; Wu, M. F.; Nash, E. R.

    1989-01-01

    Evidence is cited from these studies and those of others showing the different nature of the yearly variations of the middle atmospheres of the Northern and Southern Hemispheres. The Northern Hemisphere middle atmosphere is shown to be characterized by annual variations in planetary wave number one amplitude and the accompanying ozone transports. The Southern Hemisphere middle atmosphere is shown to be characterized by semiannual variations in the amplitude of planetary wave number one and the accompanying ozone transports. The amplitude of wave number two in both hemispheres appears to vary annually. Examination is made of the nature of the planetary wave forcing in both hemispheres as well as the planetary wave propagation characteristics in both hemispheres in an attempt to better understand this.

  12. Role of brain hemispheric dominance in anticipatory postural control strategies.

    PubMed

    Cioncoloni, David; Rosignoli, Deborah; Feurra, Matteo; Rossi, Simone; Bonifazi, Marco; Rossi, Alessandro; Mazzocchio, Riccardo

    2016-07-01

    Most of the cerebral functions are asymmetrically represented in the two hemispheres. Moreover, dexterity and coordination of the distal segment of the dominant limbs depend on cortico-motor lateralization. In this study, we investigated whether postural control may be also considered a lateralized hemispheric brain function. To this aim, 15 young subjects were tested in standing position by measuring center of pressure (COP) shifts along the anteroposterior axis (COP-Y) during dynamic posturography before and after continuous Theta Burst Stimulation (cTBS) intervention applied to the dominant or non-dominant M1 hand area as well as to the vertex. We show that when subjects were expecting a forward platform translation, the COP-Y was positioned significantly backward or forward after dominant or non-dominant M1 stimulation, respectively. We postulate that cTBS applied on M1 may have disrupted the functional connectivity between intra- and interhemispheric areas implicated in the anticipatory control of postural stability. This study suggests a functional asymmetry between the two homologous primary motor areas, with the dominant hemisphere playing a critical role in the selection of the appropriate postural control strategy. PMID:26952051

  13. The left hemisphere and the selection of learned actions.

    PubMed

    Rushworth, M F; Nixon, P D; Wade, D T; Renowden, S; Passingham, R E

    1998-01-01

    The left hemisphere's dominance for movement is well known. The basis of its dominance is less clear. We have tested 16 left hemisphere (LH) patients, 17 right hemisphere (RH) patients and 12 neurologically normal controls on a battery of five tasks. The tasks were based on animal lesion and recording studies, and human imaging and magnetic stimulation studies that identified two distributed systems that are important for the selection of motor responses and object-oriented responses. The LH patients were impaired on three response selection tasks: learning to select between joystick movement responses instructed by visual cues; learning to select between analogous object-oriented responses instructed by visual cues; learning to select movements in a sequence. Although we replicated the finding that LH damage impairs sequencing, some of the impaired tasks had no sequencing element. We therefore argue that the LH deficits are best explained as an impairment of response selection. This was confirmed by showing that LH subjects were unimpaired on a more demanding task-object discrimination learning-which imposed a greater memory load but had no response selection element. Moreover, the LH deficits could not be attributed to disorganization of movement kinematics. The lesions of the impaired LH group were widespread but always included the distributed systems known to be important for response selection-the dorsolateral frontal and parietal cortices, striatum, thalamus and white matter fascicles. PMID:9533383

  14. Analytical and Numerical Investigations into Hemisphere-Shaped Electrostatic Sensors

    PubMed Central

    Lin, Jun; Chen, Zhong-Sheng; Hu, Zheng; Yang, Yong-Min; Tang, Xin

    2014-01-01

    Electrostatic sensors have been widely used in many applications due to their advantages of low cost and robustness. Their spatial sensitivity and time-frequency characteristics are two important performance parameters. In this paper, an analytical model of the induced charge on a novel hemisphere-shaped electrostatic sensor was presented to investigate its accurate sensing characteristics. Firstly a Poisson model was built for electric fields produced by charged particles. Then the spatial sensitivity and time-frequency response functions were directly derived by the Green function. Finally, numerical calculations were done to validate the theoretical results. The results demonstrate that the hemisphere-shaped sensors have highly 3D-symmetrical spatial sensitivity expressed in terms of elementary function, and the spatial sensitivity is higher and less homogeneous near the hemispherical surface and vice versa. Additionally, the whole monitoring system, consisting of an electrostatic probe and a signal conditioner circuit, acts as a band-pass filter. The time-frequency characteristics depend strongly on the spatial position and velocity of the charged particle, the radius of the probe as well as the equivalent resistance and capacitance of the circuit. PMID:25090419

  15. Are Karakoram temperatures out of phase compared to hemispheric trends?

    NASA Astrophysics Data System (ADS)

    Asad, Fayaz; Zhu, Haifeng; Zhang, Hui; Liang, Eryuan; Muhammad, Sher; Farhan, Suhaib Bin; Hussain, Iqtidar; Wazir, Muhammad Atif; Ahmed, Moinuddin; Esper, Jan

    2016-07-01

    In contrast to a global retreating trend, glaciers in the Karakoram showed stability and/or mass gaining during the past decades. This "Karakoram Anomaly" has been assumed to result from an out-of-phase temperature trend compared to hemispheric scales. However, the short instrumental observations from the Karakoram valley bottoms do not support a quantitative assessment of long-term temperature trends in this high mountain area. Here, we presented a new April-July temperature reconstruction from the Karakoram region in northern Pakistan based on a high elevation (~3600 m a.s.l.) tree-ring chronology covering the past 438 years (AD 1575-2012). The reconstruction passes all statistical calibration and validation tests and represents 49 % of the temperature variance recorded over the 1955-2012 instrumental period. It shows a substantial warming accounting to about 1.12 °C since the mid-twentieth century, and 1.94 °C since the mid-nineteenth century, and agrees well with the Northern Hemisphere temperature reconstructions. These findings provide evidence that the Karakoram temperatures are in-phase, rather than out-of-phase, compared to hemispheric scales since the AD 1575. The synchronous temperature trends imply that the anomalous glacier behavior reported from the Karakoram may need further explanations beyond basic regional thermal anomaly.

  16. Obliquity Control On Southern Hemisphere Climate During The Last Glacial

    PubMed Central

    Fogwill, C.J.; Turney, C.S.M.; Hutchinson, D.K.; Taschetto, A.S.; England, M.H.

    2015-01-01

    Recent paleoclimate reconstructions have challenged the traditional view that Northern Hemisphere insolation and associated feedbacks drove synchronous global climate and ice-sheet volume during the last glacial cycle. Here we focus on the response of the Patagonian Ice Sheet, and demonstrate that its maximum expansion culminated at 28,400 ± 500 years before present (28.4 ± 0.5 ka), more than 5,000 years before the minima in 65°N summer insolation and the formally-defined Last Glacial Maximum (LGM) at 21,000 ± 2,000 years before present. To investigate the potential drivers of this early LGM (eLGM), we simulate the effects of orbital changes using a suite of climate models incorporating prescribed and evolving sea-ice anomalies. Our analyses suggest that Antarctic sea-ice expansion at 28.5 ka altered the location and intensity of the Southern Hemisphere storm track, triggering regional cooling over Patagonia of 5°C that extends across the wider mid-southern latitudes. In contrast, at the LGM, continued sea-ice expansion reduced regional temperature and precipitation further, effectively starving the ice sheet and resulting in reduced glacial expansion. Our findings highlight the dominant role that orbital changes can play in driving Southern Hemisphere glacial climate via the sensitivity of mid-latitude regions to changes in Antarctic sea-ice extent. PMID:26115344

  17. Learning-related brain hemispheric dominance in sleeping songbirds

    PubMed Central

    Moorman, Sanne; Gobes, Sharon M. H.; van de Kamp, Ferdinand C.; Zandbergen, Matthijs A.; Bolhuis, Johan J.

    2015-01-01

    There are striking behavioural and neural parallels between the acquisition of speech in humans and song learning in songbirds. In humans, language-related brain activation is mostly lateralised to the left hemisphere. During language acquisition in humans, brain hemispheric lateralisation develops as language proficiency increases. Sleep is important for the formation of long-term memory, in humans as well as in other animals, including songbirds. Here, we measured neuronal activation (as the expression pattern of the immediate early gene ZENK) during sleep in juvenile zebra finch males that were still learning their songs from a tutor. We found that during sleep, there was learning-dependent lateralisation of spontaneous neuronal activation in the caudomedial nidopallium (NCM), a secondary auditory brain region that is involved in tutor song memory, while there was right hemisphere dominance of neuronal activation in HVC (used as a proper name), a premotor nucleus that is involved in song production and sensorimotor learning. Specifically, in the NCM, birds that imitated their tutors well were left dominant, while poor imitators were right dominant, similar to language-proficiency related lateralisation in humans. Given the avian-human parallels, lateralised neural activation during sleep may also be important for speech and language acquisition in human infants. PMID:25761654

  18. Different hemispheric roles in recognition of happy expressions.

    PubMed

    Nakamura, Akinori; Maess, Burkhard; Knösche, Thomas R; Friederici, Angela D

    2014-01-01

    The emotional expression of the face provides an important social signal that allows humans to make inferences about other people's state of mind. However, the underlying brain mechanisms are complex and still not completely understood. Using magnetoencephalography (MEG), we analyzed the spatiotemporal structure of regional electrical brain activity in human adults during a categorization task (faces or hands) and an emotion discrimination task (happy faces or neutral faces). Brain regions that are specifically important for different aspects of processing emotional facial expressions showed interesting hemispheric dominance patterns. The dorsal brain regions showed a right predominance when participants paid attention to facial expressions: The right parietofrontal regions, including the somatosensory, motor/premotor, and inferior frontal cortices showed significantly increased activation in the emotion discrimination task, compared to in the categorization task, in latencies of 350 to 550 ms, while no activation was found in their left hemispheric counterparts. Furthermore, a left predominance of the ventral brain regions was shown for happy faces, compared to neutral faces, in latencies of 350 to 550 ms within the emotion discrimination task. Thus, the present data suggest that the right and left hemispheres play different roles in the recognition of facial expressions depending on cognitive context. PMID:24520407

  19. Hypothalamic digoxin, hemispheric chemical dominance, and Alzheimer's disease.

    PubMed

    Kurup, Ravi Kumar; Kurup, Parameswara Achutha

    2003-03-01

    This study assessed the changes in the isoprenoid pathway and the consequences of its dysfunction in Alzheimer's disease (AD). The isoprenoid pathway and digoxin status were also studied for comparison in individuals of differing hemispheric dominance to find the role of cerebral dominance in the genesis of Alzheimer's disease. There was elevation in plasma HMG CoA reductase activity, serum digoxin, and dolichol levels, and a reduction in serum magnesium, RBC membrane Na(+)-K+ ATPase activity, and serum ubiquinone levels. Serum tryptophan, serotonin, strychnine, nicotine, and quinolinic acid were elevated, while serum tyrosine, morphine, dopamine, and noradrenaline were decreased. The total serum glycosaminoglycans and glycosaminoglycan fractions, the activity of GAG degrading enzymes and glycohydrolases, carbohydrate residues of glycoproteins, and serum glycolipids were elevated in Alzheimer's disease. HDL cholesterol was reduced and free fatty acids increased. The RBC membrane glycosaminoglycans, hexose, and fucose residues of glycoproteins and cholesterol were reduced, while phospholipid increased. The activity of all free radical scavenging enzymes, concentration of glutathione, alpha tocopherol, iron binding capacity, and ceruloplasmin decreased significantly in Alzheimer's disease, while the concentration of lipid peroxidation products and NO increased. The hypomagnesemia-related NMDA excitotoxicity, ubiquinone deficiency related mitochondrial dysfunction, and altered glycoconjugates/lysosomal stability could contribute to the pathogenesis of Alzheimer's disease. The biochemical patterns, including hyperdigoxinemia observed in Alzheimer's disease, correlated with those obtained in right hemispheric chemical dominance. Right hemispheric chemical dominance is a predisposing factor for Alzheimer's disease. PMID:12803139

  20. The Unusual Southern Hemisphere Stratosphere Winter of 2002

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Nash, Eric R.

    2003-01-01

    The southern hemisphere stratospheric winter of 2002 was the most unusual winter yet observed in the southern hemisphere climate record. Temperatures near the edge of the Antarctic polar vortex were considerably warmer than normal over the entire course of the winter. The polar night jet was considerably weaker than normal, and was displaced more poleward than has been observed in previous winters. These record high temperatures and weak jet resulted from a series of wave events that took place over the course of the winter. The first large event occurred on 15 May, and the final warming occurred on 25 October. The propagation of these wave events from the troposphere is diagnosed from time series of Eliassen-Palm flux vectors. The wave events tended to occur irregularly over the course of the winter, and pre-conditioned the polar night jet for the extremely large wave event of 22 September. This large wave event resulted in the first ever observed major stratospheric warming in the southern hemisphere. This wave event split the Antarctic ozone hole. The combined effect of the wave events of the 2002 winter resulted in the smallest ozone hole observed since 1988.

  1. The Relationship Between ENSO Phases and Southern Hemisphere Jet Structure

    NASA Astrophysics Data System (ADS)

    Loeb, N.

    2015-12-01

    Tropical convection affects Southern Hemisphere jet dynamics through the process of mass outflow in the upper troposphere and lower stratosphere and through radiation of planetary wave trains through the connecting westerly waveguide. Seasonal changes and El Nino Southern Oscillation (ENSO) phases have an impact on the structure of the Subtropical, Polar and Polar Night Jet in the high latitude Southern Hemisphere. Through reanalysis of ERA-Interim data sets, an investigation of the different southern hemispheric jet structures that result from the various phases of ENSO. A classification of months into categories of El Niño, neutral and La Niña and then further sub classify the El Niño and La Niña into strong, moderate and weak events. The strength of the polar jet and subtropical jet vary greatly between the El Niño and La Niña episodes and also vary in latitudinal placement. Also, the structure of the jets vary between the Atlantic, Pacific and Indian Ocean Basins. Seasonal progression also has an impact on the structure and shape of the polar and subtropical jets. During the Winter in the Southern Atlantic Ocean, a more diffuse jet structure occurs during La Nina while a more focused jet structure is favored in El Niño periods. In addition, a strong link between the Polar-Night Jet and and the tropospheric polar jet is discovered.

  2. Obliquity Control on Southern Hemisphere Climate during the Last Glacial

    NASA Astrophysics Data System (ADS)

    Fogwill, C. J.; Hutchinson, D. K.; Turney, C. S.; Taschetto, A.; England, M. H.

    2015-12-01

    Recent paleoclimate reconstructions have challenged the traditional view that Northern Hemisphere insolation and associated feedbacks drove synchronous global climate and ice-sheet volume during the last glacial cycle. Here we focus on the response of the Patagonian Ice Sheet, and demonstrate that its maximum expansion culminated at 28,400 ± 500 years before present (28.4 ± 0.5 ka), more than 5,000 years before the minima in 65°N summer insolation and the formally-defined Last Glacial Maximum (LGM) at 21,000 ± 2,000 years before present. To investigate the potential drivers of this early LGM (eLGM), we simulate the effects of orbital changes using a suite of climate models incorporating prescribed and evolving sea-ice anomalies. Our analyses suggest that Antarctic sea-ice expansion at 28.5 ka altered the location and intensity of the Southern Hemisphere storm track, triggering regional cooling over Patagonia of 5°C that extends across the wider mid-southern latitudes. In contrast, at the LGM, continued sea-ice expansion reduced regional temperature and precipitation further, effectively starving the ice sheet and resulting in reduced glacial expansion. Our findings highlight the dominant role that orbital changes can play in driving Southern Hemisphere glacial climate via the sensitivity of mid-latitude regions to changes in Antarctic sea-ice extent.

  3. Estimation of 2006 Northern Hemisphere contrail coverage using MODIS data

    NASA Astrophysics Data System (ADS)

    Duda, David P.; Minnis, Patrick; Khlopenkov, Konstantin; Chee, Thad L.; Boeke, Robyn

    2013-02-01

    Abstract A modified automated contrail detection algorithm (CDA) using five infrared channels available from the Moderate Resolution Imaging Spectrometer onboard the Aqua satellite is used to determine linear contrail coverage over the Northern <span class="hlt">Hemisphere</span> during 2006. Commercial aircraft flight data are employed to filter false contrail detections by the CDA. The Northern <span class="hlt">Hemisphere</span> annual mean linear contrail coverage ranges from 0.07% to 0.40% for three different CDA sensitivities. Based on visual analyses, the medium sensitivity CDA provides the best estimate of linear contrail coverage, which averages 0.13%. If scaled to the Southern <span class="hlt">Hemisphere</span>, the global mean coverage would be 0.07%. Coverage is greatest during winter and least during the summer with maximum coverage over the North Atlantic. Less coverage is observed over heavy European and American traffic areas, likely as a result of difficulties in detecting linear contrails that overlap with each other and with older contrail cirrus. These results are valuable for evaluating the representation of contrails and contrail cirrus within global climate models and for retrieving contrail optical properties and radiative forcing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25761654','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25761654"><span id="translatedtitle">Learning-related brain <span class="hlt">hemispheric</span> dominance in sleeping songbirds.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moorman, Sanne; Gobes, Sharon M H; van de Kamp, Ferdinand C; Zandbergen, Matthijs A; Bolhuis, Johan J</p> <p>2015-01-01</p> <p>There are striking behavioural and neural parallels between the acquisition of speech in humans and song learning in songbirds. In humans, language-related brain activation is mostly lateralised to the left <span class="hlt">hemisphere</span>. During language acquisition in humans, brain <span class="hlt">hemispheric</span> lateralisation develops as language proficiency increases. Sleep is important for the formation of long-term memory, in humans as well as in other animals, including songbirds. Here, we measured neuronal activation (as the expression pattern of the immediate early gene ZENK) during sleep in juvenile zebra finch males that were still learning their songs from a tutor. We found that during sleep, there was learning-dependent lateralisation of spontaneous neuronal activation in the caudomedial nidopallium (NCM), a secondary auditory brain region that is involved in tutor song memory, while there was right <span class="hlt">hemisphere</span> dominance of neuronal activation in HVC (used as a proper name), a premotor nucleus that is involved in song production and sensorimotor learning. Specifically, in the NCM, birds that imitated their tutors well were left dominant, while poor imitators were right dominant, similar to language-proficiency related lateralisation in humans. Given the avian-human parallels, lateralised neural activation during sleep may also be important for speech and language acquisition in human infants. PMID:25761654</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000110367&hterms=MOLA&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DMOLA','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000110367&hterms=MOLA&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DMOLA"><span id="translatedtitle">Southern <span class="hlt">Hemisphere</span> Storm Zones on Mars: Implications of MOLA Topography</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hollingsworth, J. L.; Haberle, R. M.; Schaeffer, J.</p> <p>1999-01-01</p> <p>Using the NASA Ames Mars general circulation model and recent Mars orbiter laser altimeter (MOLA) global topography, annual-cycle simulations have been performed corresponding to a lowglobally-averaged atmospheric dust loading (tau= 0 - 3). Comparisons of key global circulation fields as simulated utilizing previous topography datasets and those using the new Mars global topography have been carried out. Values of globally and/or <span class="hlt">hemispheric</span> averaged kinetic energy associated with the longitudinally averaged (i.e., zonal) circulation and longitudinal departures (i.e., eddy components) as a function of season for simulations using the different topography datasets are provided contributions arising frommeteorological variability associated with thermal tides, stationary circulation components and recurrent weather systems (transient baroclinc and/or barotropic eddies). It can be noted that eddy activity in the northern <span class="hlt">hemisphere</span> (NH) is substantially diminished using the new topographic data, and that at some seasons, the southern <span class="hlt">hemisphere</span> (SH) activity is moderately increased. Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUSM..SH42A01M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUSM..SH42A01M"><span id="translatedtitle">The Origin of Prominences and Their <span class="hlt">Hemispheric</span> Preferences</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martens, P. C.</p> <p>2001-05-01</p> <p>We present a ``head-to-tail" linkage model for the formation, evolution, and eruption of solar filaments. The magnetic field structure of our model is based upon the observation that filaments form exclusively in filament channels with no apparent magnetic connections above the polarity inversion line. The formation of a filament in this configuration is driven by flux convergence and cancellation, which produces loop-like filaments segments with a half-turn. Filament segments of like chirality may connect and form long quiescent filaments. Such filaments are stabilized through footpoint anchoring until further cancellation at the footpoints causes their eruption. The eruption restores the original filament channel so that filament formation may resume immediately. We demonstrate that the combined workings of Hale's polarity law, Joy's law, and differential rotation introduce a strong <span class="hlt">hemispheric</span> preference in the chirality of filaments formed poleward of the sunspot belt, in agreement with observations. We analyze the magnetic fine structure of filaments formed through our model and find consistency with the observed <span class="hlt">hemispheric</span> preference for barb orientation and a simple explanation for barb formation. Finally we show that every cancellation event that generates a filament obeying the <span class="hlt">hemispheric</span> chirality preference, injects a flux tube below the surface with a poloidal field opposite to that of the ongoing cycle. We suggest that this pattern of submergence of flux represents the specific mechanism for the reversal of the poloidal flux in a Babcock-Leighton-Durney type model for the solar dynamo.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Cerebral+AND+dominance&pg=7&id=EJ756089','ERIC'); return false;" href="http://eric.ed.gov/?q=Cerebral+AND+dominance&pg=7&id=EJ756089"><span id="translatedtitle">The Representation of Discourse in the Two <span class="hlt">Hemispheres</span>: An Individual Differences Investigation</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Prat, Chantel S.; Long, Debra L.; Baynes, Kathleen</p> <p>2007-01-01</p> <p>Two experiments were conducted to investigate discourse representation in the two cerebral <span class="hlt">hemispheres</span> as a function of reading skill. We used a lateralized visual-field procedure to compare left <span class="hlt">hemisphere</span> (LH) and right <span class="hlt">hemisphere</span> (RH) sensitivity to different discourse relations in readers with varying skill levels. In Experiment 1, we…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Cerebral+AND+dominance&pg=7&id=EJ856767','ERIC'); return false;" href="http://eric.ed.gov/?q=Cerebral+AND+dominance&pg=7&id=EJ856767"><span id="translatedtitle"><span class="hlt">Hemispheric</span> Division of Function Is the Result of Independent Probabilistic Biases</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Whitehouse, Andrew J. O.; Bishop, Dorothy V. M.</p> <p>2009-01-01</p> <p>Verbal and visuospatial abilities are typically subserved by different cerebral <span class="hlt">hemispheres</span>: the left <span class="hlt">hemisphere</span> for the former and the right <span class="hlt">hemisphere</span> for the latter. However little is known of the origin of this division of function. Causal theories propose that functional asymmetry is an obligatory pattern of organisation, while statistical…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=homograph&id=EJ985209','ERIC'); return false;" href="http://eric.ed.gov/?q=homograph&id=EJ985209"><span id="translatedtitle"><span class="hlt">Hemispheric</span> Asymmetries in Meaning Selection: Evidence from the Disambiguation of Homophonic vs. Heterophonic Homographs</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Peleg, Orna; Markus, Andrey; Eviatar, Zohar</p> <p>2012-01-01</p> <p>Research investigating <span class="hlt">hemispheric</span> asymmetries in meaning selection using homophonic homographs (e.g., "bank"), suggests that the left <span class="hlt">hemisphere</span> (LH) quickly selects contextually relevant meanings, whereas the right <span class="hlt">hemisphere</span> (RH) maintains a broader spectrum of meanings including those that are contextually irrelevant (e.g., Faust & Chiarello,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Anesthesia&pg=5&id=EJ282302','ERIC'); return false;" href="http://eric.ed.gov/?q=Anesthesia&pg=5&id=EJ282302"><span id="translatedtitle">A Response to Gazzaniga: Language in the Right <span class="hlt">Hemisphere</span>, Convergent Perspectives.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Zaidel, Eran</p> <p>1983-01-01</p> <p>Gazzaniga argues that without language right <span class="hlt">hemisphere</span> cognition is vastly limited and that most normal right <span class="hlt">hemispheres</span> have no language and only "rudimentary cognition." These assertion ignore important nonlinguistic observations, as well as findings with <span class="hlt">hemispheric</span> sodium amytal anesthesia and laterality effects for complex cognitive tasks…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Memory+AND+study+AND+left+AND+right+AND+brain&pg=3&id=EJ827107','ERIC'); return false;" href="http://eric.ed.gov/?q=Memory+AND+study+AND+left+AND+right+AND+brain&pg=3&id=EJ827107"><span id="translatedtitle">When Side Matters: <span class="hlt">Hemispheric</span> Processing and the Visual Specificity of Emotional Memories</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kensinger, Elizabeth A.; Choi, Elizabeth S.</p> <p>2009-01-01</p> <p>Previous studies have shown that the right <span class="hlt">hemisphere</span> processes the visual details of objects and the emotionality of information. These two roles of the right <span class="hlt">hemisphere</span> have not been examined concurrently. In the present study, the authors examined whether right <span class="hlt">hemisphere</span> processing would lead to particularly good memory for the visual details…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=serotonin&pg=4&id=EJ903627','ERIC'); return false;" href="http://eric.ed.gov/?q=serotonin&pg=4&id=EJ903627"><span id="translatedtitle"><span class="hlt">Hemispheric</span> Specialization for Emotional Word Processing Is a Function of SSRI Responsiveness</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Walsh, Amy; McDowall, John; Grimshaw, Gina M.</p> <p>2010-01-01</p> <p>Vulnerability to depression and non-response to Selective Serotonin Reuptake Inhibitors (SSRIs) are associated with specific neurophysiological characteristics including greater right <span class="hlt">hemisphere</span> (RH) relative to left <span class="hlt">hemisphere</span> (LH) activity. The present study investigated the relationship between <span class="hlt">hemispheric</span> specialization and processing of…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=stroop+AND+effect&pg=3&id=EJ927407','ERIC'); return false;" href="http://eric.ed.gov/?q=stroop+AND+effect&pg=3&id=EJ927407"><span id="translatedtitle"><span class="hlt">Hemisphere</span> Lateralization Is Influenced by Bilingual Status and Composition of Words</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Peng, Gang; Wang, William S.-Y.</p> <p>2011-01-01</p> <p>It has been generally accepted that the left <span class="hlt">hemisphere</span> is more functionally specialized for language than the right <span class="hlt">hemisphere</span> for right-handed monolinguals. But more and more studies have also demonstrated right <span class="hlt">hemisphere</span> advantage for some language tasks with certain participants. A recent comprehensive survey has shown that hemisphere…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=recognizing+AND+facial+AND+differences&id=EJ307241','ERIC'); return false;" href="http://eric.ed.gov/?q=recognizing+AND+facial+AND+differences&id=EJ307241"><span id="translatedtitle">Multiple Modes of Right-<span class="hlt">Hemisphere</span> Information Processing: Age and Sex Differences in Facial Recognition.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Turkewitz, Gerald; Ross-Kossak, Phyllis</p> <p>1984-01-01</p> <p>Examines <span class="hlt">hemispheric</span> differences in processing tachistoscopically presented faces in right-handed 8-, 11-, and 13-year-olds. Concludes that younger children and males at all ages use a diffuse right-<span class="hlt">hemisphere</span> processing strategy in recognizing faces, whereas some older females use a more integrated right-<span class="hlt">hemispheric</span> strategy. (Author/CB)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=brain+AND+mri&pg=4&id=EJ793241','ERIC'); return false;" href="http://eric.ed.gov/?q=brain+AND+mri&pg=4&id=EJ793241"><span id="translatedtitle">Association between Therapy Outcome and Right-<span class="hlt">Hemispheric</span> Activation in Chronic Aphasia</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Richter, Maria; Miltner, Wolfgang H. R.; Straube, Thomas</p> <p>2008-01-01</p> <p>The role of the right <span class="hlt">hemisphere</span> for language processing and successful therapeutic interventions in aphasic patients is a matter of debate. This study explored brain activation in right-<span class="hlt">hemispheric</span> areas and left-<span class="hlt">hemispheric</span> perilesional areas in response to language tasks in chronic non-fluent aphasic patients before and after constraint-induced…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Bowden&id=EJ909568','ERIC'); return false;" href="http://eric.ed.gov/?q=Bowden&id=EJ909568"><span id="translatedtitle">Knowledge-Based Inferences across the <span class="hlt">Hemispheres</span>: Domain Makes a Difference</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Shears, Connie; Hawkins, Amanda; Varner, Andria; Lewis, Lindsey; Heatley, Jennifer; Twachtmann, Lisa</p> <p>2008-01-01</p> <p>Language comprehension occurs when the left-<span class="hlt">hemisphere</span> (LH) and the right-<span class="hlt">hemisphere</span> (RH) share information derived from discourse [Beeman, M. J., Bowden, E. M., & Gernsbacher, M. A. (2000). Right and left <span class="hlt">hemisphere</span> cooperation for drawing predictive and coherence inferences during normal story comprehension. "Brain and Language, 71", 310-336].…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4184861','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4184861"><span id="translatedtitle">Comparison of Phenology Models for Predicting the Onset of Growing Season over the Northern <span class="hlt">Hemisphere</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fu, Yang; Zhang, Haicheng; Dong, Wenjie; Yuan, Wenping</p> <p>2014-01-01</p> <p>Vegetation phenology models are important for examining the impact of climate change on the length of the growing season and carbon cycles in terrestrial ecosystems. However, large uncertainties in present phenology models make accurate assessment of the beginning of the growing season (BGS) a challenge. In this study, based on the satellite-based phenology product (i.e. the V005 MODIS Land Cover Dynamics (MCD12Q2) product), we calibrated four phenology models, compared their relative strength to predict vegetation phenology; and assessed the spatial pattern and interannual variability of BGS in the Northern <span class="hlt">Hemisphere</span>. The results indicated that parameter calibration significantly influences the models' accuracy. All models showed good performance in cool regions but poor performance in warm regions. On average, they explained about 67% (the Growing Degree Day model), 79% (the Biome-BGC phenology model), 73% (the Number of Growing Days model) and 68% (the Number of Chilling Days-Growing Degree Day model) of the BGS variations over the Northern <span class="hlt">Hemisphere</span>. There were substantial differences in BGS simulations among the four phenology models. Overall, the Biome-BGC phenology model performed best in predicting the BGS, and showed low biases in most boreal and cool regions. Compared with the other three models, the two-phase phenology model (NCD-GDD) showed the lowest correlation and largest biases with the MODIS phenology product, although it could catch the interannual variations well for some vegetation types. Our study highlights the need for further improvements by integrating the effects of water availability, especially for <span class="hlt">plants</span> growing in low latitudes, and the physiological adaptation of <span class="hlt">plants</span> into phenology models. PMID:25279567</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25279567','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25279567"><span id="translatedtitle">Comparison of phenology models for predicting the onset of growing season over the Northern <span class="hlt">Hemisphere</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fu, Yang; Zhang, Haicheng; Dong, Wenjie; Yuan, Wenping</p> <p>2014-01-01</p> <p>Vegetation phenology models are important for examining the impact of climate change on the length of the growing season and carbon cycles in terrestrial ecosystems. However, large uncertainties in present phenology models make accurate assessment of the beginning of the growing season (BGS) a challenge. In this study, based on the satellite-based phenology product (i.e. the V005 MODIS Land Cover Dynamics (MCD12Q2) product), we calibrated four phenology models, compared their relative strength to predict vegetation phenology; and assessed the spatial pattern and interannual variability of BGS in the Northern <span class="hlt">Hemisphere</span>. The results indicated that parameter calibration significantly influences the models' accuracy. All models showed good performance in cool regions but poor performance in warm regions. On average, they explained about 67% (the Growing Degree Day model), 79% (the Biome-BGC phenology model), 73% (the Number of Growing Days model) and 68% (the Number of Chilling Days-Growing Degree Day model) of the BGS variations over the Northern <span class="hlt">Hemisphere</span>. There were substantial differences in BGS simulations among the four phenology models. Overall, the Biome-BGC phenology model performed best in predicting the BGS, and showed low biases in most boreal and cool regions. Compared with the other three models, the two-phase phenology model (NCD-GDD) showed the lowest correlation and largest biases with the MODIS phenology product, although it could catch the interannual variations well for some vegetation types. Our study highlights the need for further improvements by integrating the effects of water availability, especially for <span class="hlt">plants</span> growing in low latitudes, and the physiological adaptation of <span class="hlt">plants</span> into phenology models. PMID:25279567</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26836196','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26836196"><span id="translatedtitle"><span class="hlt">Hemisphere</span> Asymmetry of Response to Pharmacologic Treatment in an Alzheimer's Disease Mouse Model.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Manousopoulou, Antigoni; Saito, Satoshi; Yamamoto, Yumi; Al-Daghri, Nasser M; Ihara, Masafumi; Carare, Roxana O; Garbis, Spiros D</p> <p>2016-01-01</p> <p>The aim of this study was to examine <span class="hlt">hemisphere</span> asymmetry of response to pharmacologic treatment in an Alzheimer's disease mouse model using cilostazol as a chemical stimulus. Eight-month-old mice were assigned to vehicle or cilostazol treatment for three months and <span class="hlt">hemispheres</span> were analyzed using quantitative proteomics. Bioinformatics interpretation showed that following treatment, aggregation of blood platelets significantly decreased in the right <span class="hlt">hemisphere</span> whereas neurodegeneration significantly decreased and synaptic transmission increased in the left <span class="hlt">hemisphere</span> only. Our study provides novel evidence on cerebral laterality of pharmacologic activity, with important implications in deciphering regional pharmacodynamic effects of existing drugs thus uncovering novel <span class="hlt">hemisphere</span>-specific therapeutic targets. PMID:26836196</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=493058','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=493058"><span id="translatedtitle"><span class="hlt">Hemispheric</span> asymmetries of affective processing as determined by the Minnesota Multiphasic Personality Inventory.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gasparrini, W G; Satz, P; Heilman, K; Coolidge, F L</p> <p>1978-01-01</p> <p>Patients with left <span class="hlt">hemisphere</span> disease have been noted to be depressed while those with right <span class="hlt">hemisphere</span> disease appear indifferent. While patients with left <span class="hlt">hemisphere</span> disease frequently have a greater cognitive deficit, patients with right <span class="hlt">hemisphere</span> disease have difficulty in expressing affectively intoned speech. The Minnesota Multiphasic Personality Inventory (MMPI) can demonstrate underlying affective experience and is not dependent on affectively intoned speech. The purpose of this study was to determine whether a difference in affective moods, as assessed by the MMPI, was related to laterality of lesion in patients matched for severity of cognitive and motor dysfunction. Seven of the 16 subjects with left <span class="hlt">hemisphere</span> dysfunction and none of the eight subjects with right <span class="hlt">hemisphere</span> dysfunction showed an elevation on the depression scale. This observation not only confirms previous clinical observations but also demonstrates that these asymmetries cannot be ascribed completely to <span class="hlt">hemisphere</span>-related differences in cognitive deficits or expressive abilities. PMID:660213</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20667163','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20667163"><span id="translatedtitle">Chromosome 21 non-<span class="hlt">disjunction</span> and Down syndrome birth in an Indian cohort: analysis of incidence and aetiology from family linkage data.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ghosh, Sujoy; Bhaumik, Pranami; Ghosh, Priyanka; Dey, Subrata Kumar</p> <p>2010-06-01</p> <p>We analysed the family linkage data obtained from short tandem repeat (STR) genotyping of 212 unrelated Indian families having a single Down syndrome (DS) baby each, in order to explore the incidence and aetiology of this human aneuploidy in our cohort. The estimated values of maternal meiotic I and meiotic II non-<span class="hlt">disjunction</span> (NDJ) errors of chromosome 21 (Ch 21) were approximately 78 and approximately 22%, respectively. Within the paternal outcome group, about 47 and 53% were accounted for NDJ at meiosis I and meiosis II, respectively. We estimated only approximately 2% post-zygotic mitotic errors. The comparison of average age of conception between controls and DS-bearing mothers revealed a significant difference (P<0.001) with DS-bearing women were on an average older than controls and meiotic II non-disjoined mothers were oldest among meiotic outcome groups. Our linkage analysis suggested an overall reduction in recombination by more than 50% on meiotic I non-disjoined maternal Ch 21 with error prone to susceptible chiasma formation within the approximately 5.1 kbp segment near the telomeric end. We stratified meiotic I non-disjoined women in three age groups, viz. young (<or=28 years), middle (29-34 years) and old (>or=35 years) and found linear decrease in the frequency of achiasmate meiosis from the young to the old group. In contrary, a linear increase in the multiple chiasma frequency from the young to the old group was observed. Considering these results together, we propose that the risk factors for Ch 21 NDJ are of two types, one being 'maternal age-independent' and the other being 'maternal age-dependent'. Moreover, a comparison of our present Indian dataset with that of other published data of ethnically different populations suggested that the genetics that underlies the NDJ of Ch 21 is probably universal irrespective of racial difference across human populations. The present study is the first population-based report on any DS cohort from the Indian</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT.......115C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT.......115C"><span id="translatedtitle">Measurement of forest ecosystem-atmosphere exchange of delta-carbon-13--carbon dioxide using Fourier transform infrared spectroscopy and <span class="hlt">disjunct</span> eddy covariance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cambaliza, Maria Obiminda L.</p> <p></p> <p>The measurement of the stable isotopic content and isotopic flux of atmospheric carbon dioxide is important for understanding the carbon budget on ecosystem, regional, and global spatial scales. Conventional measurements of the isotopic composition of atmospheric CO2 involve laboratory mass spectrometry analysis of grab samples from the field, which limits the location, collection frequency and throughput of samples. More technologically advanced methods (e.g. tunable diode laser spectroscopy) suffer from interferences with other chemical species. We have developed a new measurement method based on Fourier-transform infrared spectroscopy (FTIR) and <span class="hlt">disjunct</span> eddy covariance (DEC) for fast, continuous, real-time measurement of the carbon isotopic composition of atmospheric CO2. Molecular absorption is measured in the 2100 to 2500 cm -1 spectral region of the 13CO2 and 12CO2 vibration-rotation bands with concentrations of both isotopologues used to determine delta13C. We demonstrate the capability of this new technique in a managed poplar forest near Boardman, Oregon with measurements during the summers of 2005 and 2006 from a 22-meter tower in a 16-m forest canopy. Long-term calibration using reference gas cylinders yielded field accuracy and precision for the forest measurements of 0.5‰ and 0.8‰, respectively, for the 45-second cycle time between samples. The signature of ecosystem respiration derived from the nighttime vertical profile measurements of CO2-delta13C was --26.6‰, about 2‰ more enriched than the isotopic composition of measured bulk leaf samples from the forest. Ecosystem respired CO 2 was ˜1.6‰ more enriched than soil-respired CO2. A comparison of the FTIR -- DEC total CO2 fluxes against standard eddy covariance measurements showed excellent (10%) agreement. FTIR-DEC measurement of the CO2 isoflux enabled the estimation of the mean carbon isotope ratio of the photosynthetic flux (deltaP). The average deltaP (-24.9‰) was 13C</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AdSpR..55.2961W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AdSpR..55.2961W&link_type=ABSTRACT"><span id="translatedtitle">Analysis of global and <span class="hlt">hemispheric</span> temperature records and prognosis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Werner, Rolf; Valev, Dimitar; Danov, Dimitar; Guineva, Veneta; Kirillov, Andrey</p> <p>2015-06-01</p> <p>Climate changes are connected to long term variations of global and <span class="hlt">hemispheric</span> temperatures, which are important for the work out of socio-political strategy for the near future. In the paper the annual temperature time series are modeled by linear multiple regression to identify important climate forcings including external climate factors such as atmospheric CO2 content, volcanic emissions, and the total solar irradiation as well as internal factors such as El Niño-Southern oscillation, Pacific decadal oscillation and Atlantic multidecadal oscillation. Adjusted temperatures were determined by removal of all significant influences except CO2. The adjusted temperatures follow a linear dependence toward the logarithm of the CO2 content, and the coefficient of determination is about 0.91. The evolution of the adjusted temperatures suggests that the warming due to CO2 from the beginning of the studied here time interval in 1900 has never stopped and is going on up to now. The global warming rate deduced from the adjusted temperatures since 1980 is about 0.14 ± 0.02 °C/decade. The warming rate reported in the IPCC assessment report 4 based on observed global surface temperature set is about 20% higher, due to the warming by the Atlantic multidecadal oscillation additional to the anthropogenic warming. The predicted temperature evolution based on long time changes of CO2 and the Atlantic multidecadal oscillation index shows that the Northern <span class="hlt">Hemispheric</span> temperatures are modulated by the Atlantic multidecadal oscillation influence and will not change significantly to about 2040, after that they will increase speedily, just like during the last decades of the past century. The temperatures of the Southern <span class="hlt">Hemisphere</span> will increase almost linearly and don't show significant periodic changes due to Atlantic multidecadal oscillation. The concrete warming rates of course are strongly depending on the future atmospheric CO2 content.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22564479','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22564479"><span id="translatedtitle"><span class="hlt">Hemispheric</span> asymmetries and prosodic emotion recognition deficits in Parkinson's disease.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ventura, Maria I; Baynes, Kathleen; Sigvardt, Karen A; Unruh, April M; Acklin, Sarah S; Kirsch, Heidi E; Disbrow, Elizabeth A</p> <p>2012-07-01</p> <p>While Parkinson's disease (PD) has traditionally been described as a movement disorder, there is growing evidence of cognitive and social deficits associated with the disease. However, few studies have looked at multi-modal social cognitive deficits in patients with PD. We studied lateralization of both prosodic and facial emotion recognition (the ability to recognize emotional valence from either tone of voice or from facial expressions) in PD. The Comprehensive Affect Testing System (CATS) is a well-validated test of human emotion processing that has been used to study emotion recognition in several major clinical populations, but never before in PD. We administered an abbreviated version of CATS (CATS-A) to 24 medicated PD participants and 12 age-matched controls. PD participants were divided into two groups, based on side of symptom onset and unilateral motor symptom severity: left-affected (N = 12) or right-affected PD participants (N = 12). CATS-A is a computer-based button press task with eight subtests relevant to prosodic and facial emotion recognition. Left-affected PD participants with inferred predominant right-<span class="hlt">hemisphere</span> pathology were expected to have difficulty with prosodic emotion recognition since there is evidence that the processing of prosodic information is right-<span class="hlt">hemisphere</span> dominant. We found that facial emotion recognition was preserved in the PD group, however, left-affected PD participants had specific impairment in prosodic emotion recognition, especially for sadness. Selective deficits in prosodic emotion recognition suggests that (1) <span class="hlt">hemispheric</span> effects in emotion recognition may contribute to the impairment of emotional communication in a subset of people with PD and (2) the coordination of neural networks needed to decipher temporally complex social cues may be specifically disrupted in PD. PMID:22564479</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.U11C0037S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.U11C0037S"><span id="translatedtitle">Reaching Across the <span class="hlt">Hemispheres</span> with Science, Language, Arts and Technology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sparrow, E. B.; Zicus, S.; Miller, A.; Baird, A.; Page, G.</p> <p>2009-12-01</p> <p>Twelve Alaskan elementary and middle school classes (grades 3-8) partnered with twelve Australian middle school classes, with each pair using web-based strategies to develop a collaborative ice-mystery fictional book incorporating authentic polar science. Three professional development workshops were held, bringing together educators and polar scientists in two IPY education outreach projects. The Alaska workshop provided an opportunity to bring together the North American teachers for lessons on arctic and antarctic science and an earth system science program Seasons and Biomes measurement protocols, as well as methods in collaborative e-writing and art in Ice e-Mysteries: Global Student Polar e-books project. Teachers worked with University of Alaska Fairbanks (UAF) and Australian scientists to become familiar with Arctic science research, science artifacts and resources available at UAF and the University of Alaska Museum of the North. In Australia, teachers received a similar project training through the Tasmania Museum and Art Gallery (TMAG) Center for Learning and Discovery on Antarctic science and the University of Tasmania. The long-distance collaboration was accomplished through Skype, emails and a TMAG supported website. A year later, Northern <span class="hlt">Hemisphere</span> and Southern <span class="hlt">Hemisphere</span> teacher partners met in a joint workshop in Tasmania, to share their experiences, do project assessments and propose activities for future collaborations. The Australian teachers received training on Seasons and Biomes scientific measurements and the Alaskan teachers, on Tasmanian vegetation, fauna and indigenous culture, Antarctic and Southern ocean studies. This innovative project produced twelve e-polar books written and illustrated by students; heightened scientific literacy about the polar regions and the earth system; increased awareness of the environment and indigenous cultures; stronger connections to the scientific community; and lasting friendships. It also resulted in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Brain+AND+imagination&pg=5&id=ED223541','ERIC'); return false;" href="http://eric.ed.gov/?q=Brain+AND+imagination&pg=5&id=ED223541"><span id="translatedtitle">Exploring the Research concerning Left <span class="hlt">Hemisphere</span>/Right <span class="hlt">Hemisphere</span> Cognitive Processes and Examining One Instructional Technique Which May Be Implemented across the Curriculum to Produce Holistic Thinkers.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>McLendon, Gloria H.</p> <p></p> <p>Current writings on the functions of the left and right <span class="hlt">hemispheres</span> of the brain are examined, focusing upon possible implications for improving present educational techniques. It has been generally accepted by researchers that the organizational and verbalizing processes are functions of the left cerebral <span class="hlt">hemisphere</span>, while creative and intuitive…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910011738','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910011738"><span id="translatedtitle">The <span class="hlt">hemispherical</span> asymmetry of the residual polar caps on Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lindner, Bernhard Lee</p> <p>1991-01-01</p> <p>A model of the polar caps of Mars was created which allows: (1) for light penetration into the cap; (2) ice albedo to vary with age, latitude, <span class="hlt">hemisphere</span>, dust content, and solar zenith angle; and (3) for diurnal variability. The model includes the radiative effects of clouds and dust, and heat transport as represented by a thermal wind. The model reproduces polar cap regression data very well, including the survival of CO2 frost at the south pole and reproduces the general trend in the Viking Lander pressure data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890054160&hterms=contaminated&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcontaminated','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890054160&hterms=contaminated&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcontaminated"><span id="translatedtitle">Measurement of total <span class="hlt">hemispherical</span> emissivity of contaminated mirror surfaces</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Facey, T. A.; Nonnenmacher, A. L.</p> <p>1989-01-01</p> <p>The effects of dust contamination on the total <span class="hlt">hemispherical</span> emissivity (THE) of a 1.5-inch-diameter Al/MgF2-coated telescope mirror are investigated experimentally. The THE is determined by means of cooling-rate measurements in the temperature range 10-14.5 C in a vacuum of 100 ntorr or better. Photographs and drawings of the experimental setup are provided, and results for 11 dust levels are presented in tables and graphs. It is shown that dust has a significant effect on THE, but the experimental losses are only about half those predicted for perfectly black dust in perfect thermal contact with the mirror surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920055266&hterms=sonar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsonar','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920055266&hterms=sonar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsonar"><span id="translatedtitle">An ice-ocean coupled model for the Northern <span class="hlt">Hemisphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cheng, Abe; Preller, Ruth</p> <p>1992-01-01</p> <p>The Hibler ice model has been modified and adapted to a domain that includes most of the sea ice-covered areas in the Northern <span class="hlt">Hemisphere</span>. This model, joined with the Cox ocean model, is developed as an enhancement to the U.S. Navy's sea ice forecasting, PIPS, and is termed PIPS2.0. Generally, the modeled ice edge is consistent with the Navy-NOAA Joint Ice Center weekly analysis, and the modeled ice thickness distribution agrees with submarine sonar data in the central Arctic basin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/564227','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/564227"><span id="translatedtitle">Valve, compressor contracts awarded for Western <span class="hlt">Hemisphere</span> projects</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>1998-01-19</p> <p>Major valve and compressor contracts have been let for projects in the Western <span class="hlt">Hemisphere</span>. Petrobras has awarded Nuovo Pignone, Florence, a $10.5 million contract to supply 400 valves for the 1,975-mile natural-gas pipeline being constructed from Bolivia into Brazil. Additionally, Brazilian company Maritima Petroleo and TransCanada PipeLines Ltd., Calgary, have awarded Nuovo Pignone separate contracts to supply turbocompressor packages. The Brazilian contract is for offshore Campos Basin; the Canadian, for a major expansion of TCPL`s system delivering natural gas out of Alberta. The paper discusses the Bolivia-Brazil pipeline, compressor orders, and the companies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NIMPB.369...95S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NIMPB.369...95S"><span id="translatedtitle">Transit time spreads in biased paracentric <span class="hlt">hemispherical</span> deflection analyzers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sise, Omer; Zouros, Theo J. M.</p> <p>2016-02-01</p> <p>The biased paracentric <span class="hlt">hemispherical</span> deflection analyzers (HDAs) are an alternative to conventional (centric) HDAs maintaining greater dispersion, lower angular aberrations, and hence better energy resolution without the use of any additional fringing field correctors. In the present work, the transit time spread of the biased paracentric HDA is computed over a wide range of analyzer parameters. The combination of high energy resolution with good time resolution and simplicity of design makes the biased paracentric analyzers very promising for both coincidence and singles spectroscopy applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991Geo....19..273L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991Geo....19..273L"><span id="translatedtitle">First early Mesozoic amber in the Western <span class="hlt">Hemisphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Litwin, Ronald J.; Ash, Sidney R.</p> <p>1991-03-01</p> <p>Detrital amber pebbles and granules have been discovered in Upper Triassic strata on the Colorado Plateau. Although amber pre-viously has been reported from Pennsylvanian, Jurassic, Cretaceous, and Tertiary strata, we know of no other reported Triassic occurrence in North America or the Western <span class="hlt">Hemisphere</span>. The newly discovered occurrences of amber are at two localities in the lower part of the Petrified }Forest Member of the Upper Triassic Chinle Formation in Petrified Forest National Park, Arizona. The paper coals and carbonaceous paper shales containing the amber also contain fossil palynomorph assemblages that indicate a late Carnian age for these occurrences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/217457','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/217457"><span id="translatedtitle">Effect of certain cerebral <span class="hlt">hemispheric</span> diseases on dreaming.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Epstein, A W</p> <p>1979-02-01</p> <p>Dreaming may be altered by cerebral <span class="hlt">hemispheric</span> disease. A woman who sustained a probable left posterior cerebral artery thrombosis, with right homonymous hemianopsia and alexia, had virtual cessation of dreaming for at least 9 months. Four individuals with temporal lobe epilepsy experienced recurrent painful (frightening) dreams, which in two patients showed features identical to seizures. Sleep recordings showed abnormalities in all four, including rhythmic temporal epileptiform activity during REM sleep. Lesions in parieto-occipital loci may interfere with production of the visual imagery required for dreaming (negative symptom in the Jacksonian sense) while epileptic activity in temporal loci may produce painful repetitive dream imagery (positive symptom). PMID:217457</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5657742','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/5657742"><span id="translatedtitle">Grinding tool for making <span class="hlt">hemispherical</span> bores in hard materials</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Duran, E.L.</p> <p>1985-04-03</p> <p>A grinding tool for forming <span class="hlt">hemispherical</span> bores in hard materials such as boron carbide. The tool comprises a hemicircular grinding bit, formed of a metal bond diamond matrix, which is mounted transversely on one end of a tubular tool shaft. The bit includes a spherically curved outer edge surface which is the active grinding surface of the tool. Two coolant fluid ports on opposite sides of the bit enable introduction of coolant fluid through the bore of the tool shaft so as to be emitted adjacent the opposite sides of the grinding bit, thereby providing optimum cooling of both the workpiece and the bit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000037980&hterms=Parkinson&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DParkinson','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000037980&hterms=Parkinson&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DParkinson"><span id="translatedtitle">Observed <span class="hlt">Hemispheric</span> Asymmetry in Global Sea Ice Changes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cavalieri, D. J.; Gloersen, P.; Parkinson, C. L.; Comiso, J. C.; Zwally, H. J.</p> <p>1997-01-01</p> <p>From November 1978 through December 1996, the areal extent of sea ice decreased by 2.9 +/- 0.4 percent per decade in the Arctic and increased by 1.3 +/- 0.2 percent per decade in the Antarctic. The observed <span class="hlt">hemispheric</span> asymmetry in these trends is consistent with a modeled response to a carbon dioxide-induced climate warming. The interannual variations, which are 2.3 percent of the annual mean in the Arctic, with a predominant period of about 5 years, and 3.4 percent of the annual mean in the Antarctic, with a predominant period of about 3 years, are uncorrelated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930019081','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930019081"><span id="translatedtitle">Spectral infrared <span class="hlt">hemispherical</span> reflectance measurements for LDEF tray clamps</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cromwell, B. K.; Shepherd, S. D.; Pender, C. W.; Wood, B. E.</p> <p>1993-01-01</p> <p>Infrared <span class="hlt">hemispherical</span> reflectance measurements that were made on 58 chromic acid anodized tray clamps from LDEF are described. The measurements were made using a hemiellipsoidal mirror reflectometer with interferometer for wavelengths between 2-15 microns. The tray clamps investigated were from locations about the entire spacecraft and provided the opportunity for comparing the effects of atomic oxygen at each location. Results indicate there was essentially no dependence on atomic oxygen fluence for the surfaces studied, but there did appear to be a slight dependence on solar radiation exposure. The reflectances of the front sides of the tray clamps consistently were slightly higher than for the protected rear tray clamp surfaces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/5211424','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/5211424"><span id="translatedtitle">Workshop: Western <span class="hlt">hemisphere</span> network of bird banding programs</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Celis-Murillo, A.</p> <p>2007-01-01</p> <p>Purpose: To promote collaboration among banding programs in the Americas. Introduction: Bird banding and marking provide indispensable tools for ornithological research, management, and conservation of migratory birds on migratory routes, breeding and non-breeding grounds. Many countries and organizations in Latin America and the Caribbean are in the process of developing or have expressed interest in developing national banding schemes and databases to support their research and management programs. Coordination of developing and existing banding programs is essential for effective data management, reporting, archiving and security, and most importantly, for gaining a fuller understanding of migratory bird conservation issues and how the banding data can help. Currently, there is a well established bird-banding program in the U.S.A. and Canada, and programs in other countries are being developed as well. Ornithologists in many Latin American countries and the Caribbean are interested in using banding and marking in their research programs. Many in the ornithological community are interested in establishing banding schemes and some countries have recently initiated independent banding programs. With the number of long term collaborative and international initiatives increasing, the time is ripe to discuss and explore opportunities for international collaboration, coordination, and administration of bird banding programs in the Western <span class="hlt">Hemisphere</span>. We propose the second ?Western <span class="hlt">Hemisphere</span> Network of Bird Banding Programs? workshop, in association with the SCSCB, to be an essential step in the progress to strengthen international partnerships and support migratory bird conservation in the Americas and beyond. This will be the second multi-national meeting to promote collaboration among banding programs in the Americas (the first meeting was held in October 8-9, 2006 in La Mancha, Veracruz, Mexico). The Second ?Western <span class="hlt">Hemisphere</span> Network of Bird Banding Programs</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160007470','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160007470"><span id="translatedtitle"><span class="hlt">Hemispherical</span> Pluto and Charon Color Composition From New Horizons</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ennico, K.; Parker, A.; Howett, C. A. J.; Olkin, C. B.; Spencer, J. R.; Grundy, W. M.; Reuter, D. E.; Cruikshank, D. P.; Binzel, R. P.; Buie, M. W.; Stern, S. A.; Weaver, H. A.; Young, L. A.</p> <p>2016-01-01</p> <p>New Horizons flew by Pluto and its moons on July 14, 2015 [1]. In the days prior to the closest approach (C/A), panchromatic and color observations of Pluto and Charon were made covering a fully complete range of longitudes. Although only a fraction of this "late-approach" data series has been transmitted to the ground, the results indicate Pluto's latitudinal coloring trends seen on the encounter <span class="hlt">hemisphere</span> continues on the far side. Charon's red pole is visible from a multitude of longitudes and its colors are uniform with longitude at lower latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12515343','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12515343"><span id="translatedtitle">The southern <span class="hlt">hemisphere</span> ozone hole split in 2002.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Varotsos, Costas</p> <p>2002-01-01</p> <p>Among the most important aspects of the atmospheric pollution problem are the anthropogenic impacts on the stratospheric ozone layer, the related trends of the total ozone content drop and the solar ultraviolet radiation enhancement at the Earth's surface level. During September 2002, the ozone hole over the Antarctic was much smaller than in the previous six years. It has split into two separate holes, due to the appearance of sudden stratospheric warming that has never been observed before in the southern <span class="hlt">hemisphere</span>. The analysis of this unprecedented event is attempted, regarding both the meteorological and photochemical aspects, in terms of the unusual thermal field patterns and the induced polar vortex disturbances. PMID:12515343</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014600','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014600"><span id="translatedtitle">Southern <span class="hlt">hemisphere</span> origin of the Cretaceous Laytonville Limestone of California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Tarduno, J.A.; McWilliams, M.; Sliter, W.V.; Cook, H.E.; Blake, M.C., Jr.; Premoli-Silva, I.</p> <p>1986-01-01</p> <p>New paleomagnetic, paleontologic, and stratigraphic data from outcrops of the Laytonville Limestone (101 to 88 million years old) support a Southern <span class="hlt">Hemisphere</span> orgin. A paleomagnetic megaconglomerate test is statistically significant and suggests magnetization at 14?? ?? 5?? south, predating Late Cretaceous to Eocene (70 to 50 million years ago) accretion. Rapid Kula plate movement or the existence and demise of a now vanished oceanic plate (or both) are required to accommodate the greater than 50?? of poleward displacement implied by the paleomagnetic data. This rapid motion brings into question the validity of a "speed limit" for absolute plate velocity based on present-day plate motions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19760049159&hterms=potential+difference&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpotential%2Bdifference','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760049159&hterms=potential+difference&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpotential%2Bdifference"><span id="translatedtitle">On <span class="hlt">hemispheric</span> differences in evoked potentials to speech stimuli</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Galambos, R.; Smith, T. S.; Schulman-Galambos, C.; Osier, H.; Benson, P.</p> <p>1975-01-01</p> <p>Subjects were asked to count the number of times a 'target' sound occurred in lists of speech sounds (pa or ba) or pure tones (250 or 600 c/sec) in which one of the sounds (the 'frequent') appeared about four times as often as the target. The response to both targets and frequents were separately averaged from electrodes at vertex at symmetrical left and right parietal locations. The expected sequence of deflections, including P3 waves with about 350 msec latency, was found in the responses to target stimuli. Very little difference was found between the right and left <span class="hlt">hemispheric</span> responses to speech or pure tones, either frequent or target.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4863527','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4863527"><span id="translatedtitle">The role of the right <span class="hlt">hemisphere</span> in semantic control: A case-series comparison of right and left <span class="hlt">hemisphere</span> stroke</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Thompson, Hannah E.; Henshall, Lauren; Jefferies, Elizabeth</p> <p>2016-01-01</p> <p>Semantic control processes guide conceptual retrieval so that we are able to focus on non-dominant associations and features when these are required for the task or context, yet the neural basis of semantic control is not fully understood. Neuroimaging studies have emphasised the role of left inferior frontal gyrus (IFG) in controlled retrieval, while neuropsychological investigations of semantic control deficits have almost exclusively focussed on patients with left-sided damage (e.g., patients with semantic aphasia, SA). Nevertheless, activation in fMRI during demanding semantic tasks typically extends to right IFG. To investigate the role of the right <span class="hlt">hemisphere</span> (RH) in semantic control, we compared nine RH stroke patients with 21 left-<span class="hlt">hemisphere</span> SA patients, 11 mild SA cases and 12 healthy, aged-matched controls on semantic and executive tasks, plus experimental tasks that manipulated semantic control in paradigms particularly sensitive to RH damage. RH patients had executive deficits to parallel SA patients but they performed well on standard semantic tests. Nevertheless, multimodal semantic control deficits were found in experimental tasks involving facial emotions and the ‘summation’ of meaning across multiple items. On these tasks, RH patients showed effects similar to those in SA cases – multimodal deficits that were sensitive to distractor strength and cues and miscues, plus increasingly poor performance in cyclical matching tasks which repeatedly probed the same set of concepts. Thus, despite striking differences in single-item comprehension, evidence presented here suggests semantic control is bilateral, and disruption of this component of semantic cognition can be seen following damage to either <span class="hlt">hemisphere</span>. PMID:26945505</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26945505','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26945505"><span id="translatedtitle">The role of the right <span class="hlt">hemisphere</span> in semantic control: A case-series comparison of right and left <span class="hlt">hemisphere</span> stroke.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thompson, Hannah E; Henshall, Lauren; Jefferies, Elizabeth</p> <p>2016-05-01</p> <p>Semantic control processes guide conceptual retrieval so that we are able to focus on non-dominant associations and features when these are required for the task or context, yet the neural basis of semantic control is not fully understood. Neuroimaging studies have emphasised the role of left inferior frontal gyrus (IFG) in controlled retrieval, while neuropsychological investigations of semantic control deficits have almost exclusively focussed on patients with left-sided damage (e.g., patients with semantic aphasia, SA). Nevertheless, activation in fMRI during demanding semantic tasks typically extends to right IFG. To investigate the role of the right <span class="hlt">hemisphere</span> (RH) in semantic control, we compared nine RH stroke patients with 21 left-<span class="hlt">hemisphere</span> SA patients, 11 mild SA cases and 12 healthy, aged-matched controls on semantic and executive tasks, plus experimental tasks that manipulated semantic control in paradigms particularly sensitive to RH damage. RH patients had executive deficits to parallel SA patients but they performed well on standard semantic tests. Nevertheless, multimodal semantic control deficits were found in experimental tasks involving facial emotions and the 'summation' of meaning across multiple items. On these tasks, RH patients showed effects similar to those in SA cases - multimodal deficits that were sensitive to distractor strength and cues and miscues, plus increasingly poor performance in cyclical matching tasks which repeatedly probed the same set of concepts. Thus, despite striking differences in single-item comprehension, evidence presented here suggests semantic control is bilateral, and disruption of this component of semantic cognition can be seen following damage to either <span class="hlt">hemisphere</span>. PMID:26945505</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.V31C4759R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V31C4759R"><span id="translatedtitle">Holocene tephrostratigraphy in high-latitude peatlands of the Southern <span class="hlt">Hemisphere</span>: a link through time?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roland, T. P.; Amesbury, M. J.; Charman, D.; De Vleeeschouwer, F.; Hodgson, D.; Hughes, P. D. M.; Mauquoy, D.; Piotrowska, N.; Royles, J.; van Bellen, S.; Vanneste, H.</p> <p>2014-12-01</p> <p>We present preliminary tephrostratigraphic data from south Patagonian peatlands and moss banks from the Antarctic Peninsula that provide greater chronological constraint to Holocene palaeoclimatic records and increase the potential for inter-regional correlation. Relative to the Northern <span class="hlt">Hemisphere</span>, there is a paucity of high-resolution, robustly dated Holocene palaeoclimate records in the Southern <span class="hlt">Hemisphere</span>, limiting our ability to validate climate models in this region and fully understand variation in the global climate system over time. In the absence of long-term instrumental data, multi-proxy (testate amoebae, <span class="hlt">plant</span> macrofossils, δ13C, δ18O and δD) palaeoclimatic records from south Patagonian peatlands can provide valuable information about the long-term variability of the southern westerlies, a key component in determining the Southern Ocean's function as a sink or source of atmospheric carbon dioxide. Similarly, multi-proxy palaeoclimatic reconstructions from moss banks provide a unique terrestrial palaeoenvironmental archive from the Antarctic Peninsula, where records of past ecological change are rare and provide vital context for the recent, rapid biotic change recorded since the mid-20th century. Robust chronologies are imperative for the accurate examination of spatial and temporal patterns in Holocene climate variation. Previous work has confirmed the presence of discrete tephra horizons in south Patagonian peatlands and Antarctic Peninsula moss banks but the examination of distal, cryptotephras is currently underemployed as a geochronological tool. The chronological potential of these archives is considerable, given their high and largely continuous accumulation rates and suitability for 14C dating, presenting additional opportunities to refine the ages of major Holocene eruptions. Here, we present initial tephrostratigraphic results from both regions and explore the links between them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26706706','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26706706"><span id="translatedtitle">Hearing it right: Evidence of <span class="hlt">hemispheric</span> lateralization in auditory imagery.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Prete, Giulia; Marzoli, Daniele; Brancucci, Alfredo; Tommasi, Luca</p> <p>2016-02-01</p> <p>An advantage of the right ear (REA) in auditory processing (especially for verbal content) has been firmly established in decades of behavioral, electrophysiological and neuroimaging research. The laterality of auditory imagery, however, has received little attention, despite its potential relevance for the understanding of auditory hallucinations and related phenomena. In Experiments 1-4 we find that right-handed participants required to imagine hearing a voice or a sound unilaterally show a strong population bias to localize the self-generated auditory image at their right ear, likely the result of left-<span class="hlt">hemispheric</span> dominance in auditory processing. In Experiments 5-8 - by means of the same paradigm - it was also ascertained that the right-ear bias for hearing imagined voices depends just on auditory attention mechanisms, as biases due to other factors (i.e., lateralized movements) were controlled. These results, suggesting a central role of the left <span class="hlt">hemisphere</span> in auditory imagery, demonstrate that brain asymmetries can drive strong lateral biases in mental imagery. PMID:26706706</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JMiMi..24l5028G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014JMiMi..24l5028G&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Hemispherical</span> micro-resonators from atomic layer deposition</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gray, Jason M.; Houlton, John P.; Gertsch, Jonas C.; Brown, Joseph J.; Rogers, Charles T.; George, Steven M.; Bright, Victor M.</p> <p>2014-12-01</p> <p><span class="hlt">Hemispherical</span> shell micro-resonators may be used as gyroscopes to potentially enable precision inertial navigation and guidance at low cost and size. Such devices require a high degree of symmetry and large quality factors (Q). Fabricating the devices from atomic layer deposition (ALD) facilitates symmetry through ALD’s high conformality and low surface roughness. To maximize Q, the shells’ geometry is optimized using finite element method (FEM) studies to reduce thermoelastic dissipation and anchor loss. The shells are fabricated by etching <span class="hlt">hemispherical</span> molds in Si (1 1 1) substrates with a 2:7:1 volumetric ratio of hydrofluoric:nitric:acetic acids, and conformally coating and patterning the molds with ALD Al2O3. The Al2O3 shells are then released from the surrounding Si substrate with an SF6 plasma. The resulting shells typically have radii around 50 µm and thicknesses close to 50 nm. The shells are highly symmetric, with radial deviations between 0.22 and 0.49%, and robust enough to be driven on resonance at amplitudes 10 × their thickness, sufficient to visualize the resonance mode shapes in an SEM. Resonance frequencies are around 60 kHz, with Q values between 1000 and 2000. This Q is lower than the 106 predicted by FEM, implying that Q is being limited by unmodeled sources of energy loss, most likely from surface effects or material defects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007AIPC..952..207H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007AIPC..952..207H&link_type=ABSTRACT"><span id="translatedtitle">Genetic biomarkers for brain <span class="hlt">hemisphere</span> differentiation in Parkinson's Disease</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hourani, Mou'ath; Mendes, Alexandre; Berretta, Regina; Moscato, Pablo</p> <p>2007-11-01</p> <p>This work presents a study on the genetic profile of the left and right <span class="hlt">hemispheres</span> of the brain of a mouse model of Parkinson's disease (PD). The goal is to characterize, in a genetic basis, PD as a disease that affects these two brain regions in different ways. Using the same whole-genome microarray expression data introduced by Brown et al. (2002) [1], we could find significant differences in the expression of some key genes, well-known to be involved in the mechanisms of dopamine production control and PD. The problem of selecting such genes was modeled as the MIN (α,β)—FEATURE SET problem [2]; a similar approach to that employed previously to find biomarkers for different types of cancer using gene expression microarray data [3]. The Feature Selection method produced a series of genetic signatures for PD, with distinct expression profiles in the Parkinson's model and control mice experiments. In addition, a close examination of the genes composing those signatures shows that many of them belong to genetic pathways or have ontology annotations considered to be involved in the onset and development of PD. Such elements could provide new clues on which mechanisms are implicated in <span class="hlt">hemisphere</span> differentiation in PD.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EL....10449001D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EL....10449001D"><span id="translatedtitle"><span class="hlt">Hemispherical</span> Parker waves driven by thermal shear in planetary dynamos</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dietrich, W.; Schmitt, D.; Wicht, J.</p> <p>2013-11-01</p> <p>Planetary and stellar magnetic fields are thought to be sustained by helical motions (α-effect) and, if present, differential rotation (Ω-effect). In the Sun, the strong differential rotation in the tachocline is responsible for an efficient Ω-effect creating a strong axisymmetric azimuthal magnetic field. This is a prerequisite for Parker dynamo waves that may be responsible for the solar cycle. In the liquid iron cores of terrestrial planets, the Coriolis force organizes convection into columns with a strong helical flow component. These likely dominate magnetic field generation while the Ω-effect is of secondary importance. Here we use numerical simulations to show that the planetary dynamo scenario may change when the heat flux through the outer boundary is higher in one <span class="hlt">hemisphere</span> than in the other. A <span class="hlt">hemispherical</span> dynamo is promoted that is dominated by fierce thermal wind responsible for a strong Ω-effect. As a consequence Parker dynamo waves are excited equivalent to those predicted for the Sun. They obey the same dispersion relation and propagation characteristics. We suggest that Parker waves may therefore also play a role in planetary dynamos for all scenarios where zonal flows become an important part of convective motions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16009238','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16009238"><span id="translatedtitle"><span class="hlt">Hemispheric</span> asymmetry in spatial attention across the menstrual cycle.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hausmann, Markus</p> <p>2005-01-01</p> <p>Functional cerebral asymmetries (FCAs) are known to fluctuate across the menstrual cycle. The mechanisms of these sex hormonal modulations are poorly understood. It has been suggested that gonadal steroid hormones might suppress or specifically activate one <span class="hlt">hemisphere</span>. However, recent studies suggest that high levels of gonadal steroid hormones reduce FCAs by its modulating effects on cortico-cortical transmission. To investigate the activating effects of gonadal steroid hormones on the interhemispheric interaction, a visual line-bisection task was administered to normally cycling women during menses and the midluteal cycle phase as well as to similar-aged healthy men. The results replicate previous findings of a sex difference in line-bisection as a function of hand-use and show that the hand-use effect fluctuates across the menstrual cycle. High levels of estradiol during the midluteal phase were related to a decrease of the hand-use effect. It is concluded that cycle-related fluctuations in levels of gonadal steroid hormones affect <span class="hlt">hemispheric</span> asymmetry of spatial attention, presumably by interhemispheric spreading of neuronal activation. PMID:16009238</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26729880','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26729880"><span id="translatedtitle">Cortical cell and neuron density estimates in one chimpanzee <span class="hlt">hemisphere</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Collins, Christine E; Turner, Emily C; Sawyer, Eva Kille; Reed, Jamie L; Young, Nicole A; Flaherty, David K; Kaas, Jon H</p> <p>2016-01-19</p> <p>The density of cells and neurons in the neocortex of many mammals varies across cortical areas and regions. This variability is, perhaps, most pronounced in primates. Nonuniformity in the composition of cortex suggests regions of the cortex have different specializations. Specifically, regions with densely packed neurons contain smaller neurons that are activated by relatively few inputs, thereby preserving information, whereas regions that are less densely packed have larger neurons that have more integrative functions. Here we present the numbers of cells and neurons for 742 discrete locations across the neocortex in a chimpanzee. Using isotropic fractionation and flow fractionation methods for cell and neuron counts, we estimate that neocortex of one <span class="hlt">hemisphere</span> contains 9.5 billion cells and 3.7 billion neurons. Primary visual cortex occupies 35 cm(2) of surface, 10% of the total, and contains 737 million densely packed neurons, 20% of the total neurons contained within the <span class="hlt">hemisphere</span>. Other areas of high neuron packing include secondary visual areas, somatosensory cortex, and prefrontal granular cortex. Areas of low levels of neuron packing density include motor and premotor cortex. These values reflect those obtained from more limited samples of cortex in humans and other primates. PMID:26729880</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4725503','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4725503"><span id="translatedtitle">Cortical cell and neuron density estimates in one chimpanzee <span class="hlt">hemisphere</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Collins, Christine E.; Turner, Emily C.; Sawyer, Eva Kille; Reed, Jamie L.; Young, Nicole A.; Flaherty, David K.; Kaas, Jon H.</p> <p>2016-01-01</p> <p>The density of cells and neurons in the neocortex of many mammals varies across cortical areas and regions. This variability is, perhaps, most pronounced in primates. Nonuniformity in the composition of cortex suggests regions of the cortex have different specializations. Specifically, regions with densely packed neurons contain smaller neurons that are activated by relatively few inputs, thereby preserving information, whereas regions that are less densely packed have larger neurons that have more integrative functions. Here we present the numbers of cells and neurons for 742 discrete locations across the neocortex in a chimpanzee. Using isotropic fractionation and flow fractionation methods for cell and neuron counts, we estimate that neocortex of one <span class="hlt">hemisphere</span> contains 9.5 billion cells and 3.7 billion neurons. Primary visual cortex occupies 35 cm2 of surface, 10% of the total, and contains 737 million densely packed neurons, 20% of the total neurons contained within the <span class="hlt">hemisphere</span>. Other areas of high neuron packing include secondary visual areas, somatosensory cortex, and prefrontal granular cortex. Areas of low levels of neuron packing density include motor and premotor cortex. These values reflect those obtained from more limited samples of cortex in humans and other primates. PMID:26729880</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA00007&hterms=North+pole&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DNorth%2Bpole','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA00007&hterms=North+pole&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DNorth%2Bpole"><span id="translatedtitle"><span class="hlt">Hemispheric</span> View of Venus Centered at the North Pole</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1995-01-01</p> <p>The <span class="hlt">hemispheric</span> view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered on the North Pole. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions. An orthographic projection was used, simulating a distant view of one <span class="hlt">hemisphere</span> of the planet. The Magellan mission was managed for NASA by Jet Propulsion Laboratory (JPL), Pasadena, CA. Data processed by JPL, the Massachusetts Institute of Technology, Cambridge, MA, and the U.S. Geological Survey, Flagstaff, AZ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3184092','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3184092"><span id="translatedtitle"><span class="hlt">Hemispheric</span> Asymmetries in Speech Perception: Sense, Nonsense and Modulations</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rosen, Stuart; Wise, Richard J. S.; Chadha, Shabneet; Conway, Eleanor-Jayne; Scott, Sophie K.</p> <p>2011-01-01</p> <p>Background The well-established left <span class="hlt">hemisphere</span> specialisation for language processing has long been claimed to be based on a low-level auditory specialization for specific acoustic features in speech, particularly regarding ‘rapid temporal processing’. Methodology A novel analysis/synthesis technique was used to construct a variety of sounds based on simple sentences which could be manipulated in spectro-temporal complexity, and whether they were intelligible or not. All sounds consisted of two noise-excited spectral prominences (based on the lower two formants in the original speech) which could be static or varying in frequency and/or amplitude independently. Dynamically varying both acoustic features based on the same sentence led to intelligible speech but when either or both acoustic features were static, the stimuli were not intelligible. Using the frequency dynamics from one sentence with the amplitude dynamics of another led to unintelligible sounds of comparable spectro-temporal complexity to the intelligible ones. Positron emission tomography (PET) was used to compare which brain regions were active when participants listened to the different sounds. Conclusions Neural activity to spectral and amplitude modulations sufficient to support speech intelligibility (without actually being intelligible) was seen bilaterally, with a right temporal lobe dominance. A left dominant response was seen only to intelligible sounds. It thus appears that the left <span class="hlt">hemisphere</span> specialisation for speech is based on the linguistic properties of utterances, not on particular acoustic features. PMID:21980349</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3196305','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3196305"><span id="translatedtitle">Right <span class="hlt">Hemispheric</span> Participation in Semantic Decision Improves Performance</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Donnelly, Kiely M.; Allendorfer, Jane B.; Szaflarski, Jerzy P.</p> <p>2011-01-01</p> <p>Functional neuroimaging studies in healthy adults demonstrate involvement of a left-lateralized network of frontal, temporal, and parietal regions during a variety of semantic processing tasks. While these areas are believed to be fundamental to semantic processing, it is unclear if task performance is correlated with differential recruitment of these or other brain regions. The objective of this study was to identify the structures underlying improved accuracy on a semantic decision task. We also investigated whether extra-scanner performance on the Boston Naming Test (BNT) and Semantic Fluency Test (SFT), neuropsychological measures of semantic retrieval, is correlated with specific areas of activation during the semantic decision/tone decision (SDTD) fMRI task. Fifty-two healthy, right-handed individuals performed a block-design SDTD task. Regression analyses revealed that increased performance on this task was associated with activation in the right inferior parietal lobule. Higher SFT performance resulted in greater recruitment of right frontal regions; improved performance on BNT was associated with more widespread activation in prefrontal, temporal, and parietal cortex bilaterally, although this activation appeared to be stronger in the right <span class="hlt">hemisphere</span>. Overall, our results suggest that improved performance on both intra- and extra-scanner measures of semantic processing are associated with increased recruitment of right <span class="hlt">hemispheric</span> regions. PMID:21937029</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012GeoRL..3919806H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012GeoRL..3919806H"><span id="translatedtitle">Monsoonal influence on Southern <span class="hlt">Hemisphere</span> 14CO2</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hua, Quan; Barbetti, Mike; Levchenko, Vladimir A.; D'Arrigo, Rosanne D.; Buckley, Brendan M.; Smith, Andrew M.</p> <p>2012-10-01</p> <p>Annual rings of a cross-dated teak tree core from Muna Island, Sulawesi, Indonesia in the southern equatorial tropics were analysed for radiocarbon from 1951-1979. 14C levels at Muna started rising in 1956 and reached a maximum value of 667‰ in early 1965. The Muna Δ14C levels are significantly higher than those derived from the other Southern <span class="hlt">Hemisphere</span> (SH) 14C records (including tree rings and atmospheric CO2 sampling) for 1959 and 1963-1965. During the growing season of teak tree rings at this location (Nov-Apr) the Inter-tropical Convergence Zone (ITCZ) moves southward of Muna. Our results indicate that the island is strongly influenced by Northern <span class="hlt">Hemisphere</span> (NH) air masses carried by the winter Asian monsoon, while the other more southerly SH sites remain covered by SH air masses. This monsoonal effect on atmospheric 14C at Muna is evident during the periods of rapidly rising atmospheric 14C (1959 and 1963-1965), when there is an enhanced 14C contrast between northern and southern air masses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25903224','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25903224"><span id="translatedtitle">Leaf onset in the northern <span class="hlt">hemisphere</span> triggered by daytime temperature.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Piao, Shilong; Tan, Jianguang; Chen, Anping; Fu, Yongshuo H; Ciais, Philippe; Liu, Qiang; Janssens, Ivan A; Vicca, Sara; Zeng, Zhenzhong; Jeong, Su-Jong; Li, Yue; Myneni, Ranga B; Peng, Shushi; Shen, Miaogen; Peñuelas, Josep</p> <p>2015-01-01</p> <p>Recent warming significantly advanced leaf onset in the northern <span class="hlt">hemisphere</span>. This signal cannot be accurately reproduced by current models parameterized by daily mean temperature (T(mean)). Here using in situ observations of leaf unfolding dates (LUDs) in Europe and the United States, we show that the interannual anomalies of LUD during 1982-2011 are triggered by daytime (Tmax) more than by nighttime temperature (T(min)). Furthermore, an increase of 1 °C in Tmax would advance LUD by 4.7 days in Europe and 4.3 days in the United States, more than the conventional temperature sensitivity estimated from T(mean). The triggering role of Tmax, rather than the T(min) or T(mean) variable, is also supported by analysis of the large-scale patterns of satellite-derived vegetation green-up in spring in the northern <span class="hlt">hemisphere</span> (>30 °N). Our results suggest a new conceptual framework of leaf onset using daytime temperature to improve the performance of phenology modules in current Earth system models. PMID:25903224</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4423217','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4423217"><span id="translatedtitle">Leaf onset in the northern <span class="hlt">hemisphere</span> triggered by daytime temperature</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Piao, Shilong; Tan, Jianguang; Chen, Anping; Fu, Yongshuo H.; Ciais, Philippe; Liu, Qiang; Janssens, Ivan A.; Vicca, Sara; Zeng, Zhenzhong; Jeong, Su-Jong; Li, Yue; Myneni, Ranga B.; Peng, Shushi; Shen, Miaogen; Peñuelas, Josep</p> <p>2015-01-01</p> <p>Recent warming significantly advanced leaf onset in the northern <span class="hlt">hemisphere</span>. This signal cannot be accurately reproduced by current models parameterized by daily mean temperature (Tmean). Here using in situ observations of leaf unfolding dates (LUDs) in Europe and the United States, we show that the interannual anomalies of LUD during 1982–2011 are triggered by daytime (Tmax) more than by nighttime temperature (Tmin). Furthermore, an increase of 1 °C in Tmax would advance LUD by 4.7 days in Europe and 4.3 days in the United States, more than the conventional temperature sensitivity estimated from Tmean. The triggering role of Tmax, rather than the Tmin or Tmean variable, is also supported by analysis of the large-scale patterns of satellite-derived vegetation green-up in spring in the northern <span class="hlt">hemisphere</span> (>30°N). Our results suggest a new conceptual framework of leaf onset using daytime temperature to improve the performance of phenology modules in current Earth system models. PMID:25903224</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/10583952','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10583952"><span id="translatedtitle">Global Warming and Northern <span class="hlt">Hemisphere</span> Sea Ice Extent.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vinnikov; Robock; Stouffer; Walsh; Parkinson; Cavalieri; Mitchell; Garrett; Zakharov</p> <p>1999-12-01</p> <p>Surface and satellite-based observations show a decrease in Northern <span class="hlt">Hemisphere</span> sea ice extent during the past 46 years. A comparison of these trends to control and transient integrations (forced by observed greenhouse gases and tropospheric sulfate aerosols) from the Geophysical Fluid Dynamics Laboratory and Hadley Centre climate models reveals that the observed decrease in Northern <span class="hlt">Hemisphere</span> sea ice extent agrees with the transient simulations, and both trends are much larger than would be expected from natural climate variations. From long-term control runs of climate models, it was found that the probability of the observed trends resulting from natural climate variability, assuming that the models' natural variability is similar to that found in nature, is less than 2 percent for the 1978-98 sea ice trends and less than 0.1 percent for the 1953-98 sea ice trends. Both models used here project continued decreases in sea ice thickness and extent throughout the next century. PMID:10583952</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/9646758','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/9646758"><span id="translatedtitle"><span class="hlt">Hemispheric</span> titanium porous coated acetabular component without screw fixation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dorr, L D; Wan, Z; Cohen, J</p> <p>1998-06-01</p> <p>One hundred fifteen hips in 108 patients with primary total hip arthroplasty using the anatomic porous replacement <span class="hlt">hemispheric</span> acetabular component implanted without adjunctive screw fixation had a mean postoperative followup time of 6 years (range, 5-7.4 years). Clinical evaluation was performed using the Harris hip score and patient self assessment using a modified Short Form-36 questionnaire. Radiographs were measured for radiolucent lines, polyethylene wear, osteolysis, migration, and fractures. No acetabular metal shell had been revised for loosening or was radiographically loose with or without migration (more than 3 mm) at final followup. Reoperation was done in nine (8%) hips because of polyethylene insert wear or disassembly. No fracture of the acetabular bone occurred at the time of surgery or was observed on radiograph. Fixation of the metal shell was stable, with progressive radiolucent lines observed at final followup in 2% of the hips. Osteolysis was recorded in one patient with two acetabular components. The fixation of noncemented <span class="hlt">hemispheric</span> porous coated acetabular components is more related to the technique of acetabular bone preparation and press fit implantation than to whether additional screws or peg fixation are used. Fixation of this acetabular component without screws at an average of 6 years after surgery is reproducible and predictable in primary hip arthroplasty. The design of modular polyethylene inserts has been improved and should reduce the wear rate of reoperations of the polyethylene insert. PMID:9646758</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JCAP...06..042M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JCAP...06..042M&link_type=ABSTRACT"><span id="translatedtitle">Direction dependence of cosmological parameters due to cosmic <span class="hlt">hemispherical</span> asymmetry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mukherjee, Suvodip; Aluri, Pavan K.; Das, Santanu; Shaikh, Shabbir; Souradeep, Tarun</p> <p>2016-06-01</p> <p>Persistent evidence for a cosmic <span class="hlt">hemispherical</span> asymmetry in the temperature field of cosmic microwave background (CMB) as observed by both WMAP as well as PLANCK increases the possibility of its cosmological origin. Presence of this signal may lead to different values for the standard model cosmological parameters in different directions, and that can have significant implications for other studies where they are used. We investigate the effect of this cosmic <span class="hlt">hemispherical</span> asymmetry on cosmological parameters using non-isotropic Gaussian random simulations injected with both scale dependent and scale independent modulation strengths. Our analysis shows that As and ns are the most susceptible parameters to acquire position dependence across the sky for the kind of isotropy breaking phenomena under study. As expected, we find maximum variation arises for the case of scale independent modulation of CMB anisotropies. We find that scale dependent modulation profile as seen in PLANCK data could lead to only 1.25σ deviation in As in comparison to its estimate from isotropic CMB sky.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA00160&hterms=Longitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DLongitude','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA00160&hterms=Longitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DLongitude"><span id="translatedtitle"><span class="hlt">Hemispheric</span> View of Venus Centered at 270 Degrees East Longitude</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1995-01-01</p> <p>The <span class="hlt">hemispheric</span> view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered at 270 degrees east longitude. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions. An orthographic projection was used, simulating a distant view of one <span class="hlt">hemisphere</span> of the planet. The Magellan mission was managed for NASA by Jet Propulsion Laboratory (JPL), Pasadena, CA. Data processed by JPL, the Massachusetts Institute of Technology, Cambridge, MA, and the U.S. Geological Survey, Flagstaff, AZ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA00158&hterms=Longitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DLongitude','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA00158&hterms=Longitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DLongitude"><span id="translatedtitle"><span class="hlt">Hemispheric</span> View of Venus Centered at 90 Degrees East Longitude</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1995-01-01</p> <p>The <span class="hlt">hemispheric</span> view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered at 90 degrees east longitude. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions. An orthographic projection was used, simulating a distant view of one <span class="hlt">hemisphere</span> of the planet. The Magellan mission was managed for NASA by Jet Propulsion Laboratory (JPL), Pasadena, CA. Data processed by JPL, the Massachusetts Institute of Technology, Cambridge, MA, and the U.S. Geological Survey, Flagstaff, AZ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA00159&hterms=Longitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DLongitude','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA00159&hterms=Longitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DLongitude"><span id="translatedtitle"><span class="hlt">Hemispheric</span> View of Venus Centered at 180 Degrees East Longitude</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1995-01-01</p> <p>The <span class="hlt">hemispheric</span> view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered at 180 degrees east longitude. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions. An orthographic projection was used, simulating a distant view of one <span class="hlt">hemisphere</span> of the planet. The Magellan mission was managed for NASA by Jet Propulsion Laboratory (JPL), Pasadena, CA. Data processed by JPL, the Massachusetts Institute of Technology, Cambridge, MA, and the U.S. Geological Survey, Flagstaff, AZ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA00157&hterms=Longitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DLongitude','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA00157&hterms=Longitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DLongitude"><span id="translatedtitle"><span class="hlt">Hemispheric</span> View of Venus Centered at 0 Degrees East Longitude</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1995-01-01</p> <p>The <span class="hlt">hemispheric</span> view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered at 0 degrees east longitude. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of this image is about 3 km. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from the Earth-based Arecibo radar in a region centered roughly on 0 degree latitude and longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features, and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions. An orthographic projection was used, simulating a distant view of one <span class="hlt">hemisphere</span> of the planet. The Magellan mission was managed for NASA by Jet Propulsion Laboratory (JPL), Pasadena, CA. Data processed by JPL, the Massachusetts Institute of Technology, Cambridge, MA, and the U.S. Geological Survey, Flagstaff, AZ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.A33J3334S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.A33J3334S"><span id="translatedtitle"><span class="hlt">Hemispheric</span> Differences in Tropical Lower Stratospheric Constituent Seasonal Cycles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stolarski, R. S.; Waugh, D. W.</p> <p>2014-12-01</p> <p>The measured seasonal cycle of ozone in the lower stratosphere shows significant differences between the northern and southern tropics. The amplitude of the seasonal cycle is larger in the northern tropics than in the southern tropics with a 2-3 month phase difference between the <span class="hlt">hemispheres</span>. MLS data shows a distinct double peak in the magnitude of the northern-tropical seasonal cycle of ozone (in percent) with maxima at 100 hPa and 68 hPa and a relative at 82 hPa. SAGE and HALOE data show a single maximum located near 80 hPa. Analysis of two years of OMPS-limb data from the Suomi-NPP mission confirms the double peak structure measured by MLS. We will show comparisons of data from MLS and OMPS-limb and will examine the interannual variability of the double-peak structure from 10 years of MLS data. It appears that vertical advection is the dominant cause of tracer annual cycles in the southern tropics, while horizontal mixing dominates in the northern tropics. We argue that separating data into separate tropical regions for each <span class="hlt">hemisphere</span> and examining the seasonal cycle and its interannual variability will lead to increased understanding of the processes that govern transport of ozone and other tracers in the tropical and sub-tropical lower stratosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18986695','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18986695"><span id="translatedtitle">Developmental dyslexia and widespread activation across the cerebellar <span class="hlt">hemispheres</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Baillieux, Hanne; Vandervliet, Everhard J M; Manto, Mario; Parizel, Paul M; De Deyn, Peter P; Mariën, Peter</p> <p>2009-02-01</p> <p>Developmental dyslexia is the most common learning disability in school-aged children with an estimated incidence of five to ten percent. The cause and pathophysiological substrate of this developmental disorder is unclear. Recently, a possible involvement of the cerebellum in the pathogenesis of dyslexia has been postulated. In this study, 15 dyslexic children and 7 age-matched control subjects were investigated by means of functional neuroimaging (fMRI) using a noun-verb association paradigm. Comparison of activation patterns between dyslexic and control subjects revealed distinct and significant differences in cerebral and cerebellar activation. Control subjects showed bilaterally well-defined and focal activation patterns in the frontal and parietal lobes and the posterior regions of the cerebellar <span class="hlt">hemispheres</span>. The dyslexic children, however, presented widespread and diffuse activations on the cerebral and cerebellar level. Cerebral activations were found in frontal, parietal, temporal and occipital regions. Activations in the cerebellum were found predominantly in the cerebellar cortex, including Crus I, Crus II, <span class="hlt">hemispheric</span> lobule VI, VII and vermal lobules I, II, III, IV and VII. This preliminary study is the first to reveal a significant difference in cerebellar functioning between dyslexic children and controls during a semantic association task. As a result, we propose a new hypothesis regarding the pathophysiological mechanisms of developmental dyslexia. Given the sites of activation in the cerebellum in the dyslexic group, a defect of the intra-cerebellar distribution of activity is suspected, suggesting a disorder of the processing or transfer of information within the cerebellar cortex. PMID:18986695</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900051716&hterms=transpiration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dtranspiration','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900051716&hterms=transpiration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dtranspiration"><span id="translatedtitle">Shock/shock interference on a transpiration cooled <span class="hlt">hemispherical</span> model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nowak, Robert J.; Wieting, Allan R.; Holden, Michael S.</p> <p>1990-01-01</p> <p>Experimental results are presented which show the effectiveness of transpiration cooling in reducing the peak heat flux caused by an impinging shock on a bow shock of a <span class="hlt">hemispherical</span> model. The 12-inch diameter <span class="hlt">hemispherical</span> transpiration model with helium coolant was tested in the Calspan 48-inch Hypersonic Shock Tunnel at nominal Mach 12.1 and freestream unit Reynolds number of 0.33 x 10 to the 6th/ft. An incident shock wave, generated by a blunt flat-plate shock generator inclined at 10 deg to the freestream, intersected the bow shock of the model to produce shock/shock interference. The stagnation heat flux without coolant or shock/shock interference was about 1.6 times a smooth surface laminar prediction due to effective roughness of the coolant ejection slots. A coolant mass flux 31 percent of the freestream mass flux reduced the stagnation heat flux to zero without shock/shock interference. However, for the same coolant mass flux and with shock/shock interference the peak heat flux was only reduced 8.3 percent, even though the total integrated heat load was reduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4138500','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4138500"><span id="translatedtitle">Right-<span class="hlt">hemisphere</span> (spatial?) acalculia and the influence of neglect</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Benavides-Varela, Silvia; Pitteri, Marco; Priftis, Konstantinos; Passarini, Laura; Meneghello, Francesca; Semenza, Carlo</p> <p>2014-01-01</p> <p>The present study aimed at exploring basic number and calculation abilities in right-<span class="hlt">hemisphere</span> damaged patients (RHD), focusing primarily on one-digit orally presented tasks, which do not require explicit visuo-spatial abilities. Twenty-four non mentally-deteriorated RHD patients [12 with clinical neglect (RHDN+), 12 without clinical neglect (RHDN−)], and 12 healthy controls were included in the study. Participants were administered an ad hoc numerical battery assessing abilities such as counting, number magnitude comparison, writing and reading Arabic numerals and mental calculation, among others. Significant differences emerged among healthy controls and both the RHDN+ group and the RHDN− group, suggesting that the mathematical impairment of RHD patients does not necessarily correspond to the presence of left-neglect. A detailed analysis of the sub-tests of the battery evidenced expected differences among RHDN+ patients, RHDN− patients, and controls in writing and reading Arabic numerals. Crucially, differences between RHDN+ patients and controls were also found in tasks such as mental subtraction and mental multiplication, which do not require written visuo-spatial abilities. The present findings thus suggest that unilateral right <span class="hlt">hemisphere</span> lesions may produce specific representational deficits that affect simple mental calculation, and not only the spatial arrangement of multi-digit written numbers as previously thought. PMID:25191257</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=cerebro&id=EJ808574','ERIC'); return false;" href="http://eric.ed.gov/?q=cerebro&id=EJ808574"><span id="translatedtitle">Reorganization of the Cerebro-Cerebellar Network of Language Production in Patients with Congenital Left-<span class="hlt">Hemispheric</span> Brain Lesions</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lidzba, K.; Wilke, M.; Staudt, M.; Krageloh-Mann, I.; Grodd, W.</p> <p>2008-01-01</p> <p>Patients with congenital lesions of the left cerebral <span class="hlt">hemisphere</span> may reorganize language functions into the right <span class="hlt">hemisphere</span>. In these patients, language production is represented homotopically to the left-<span class="hlt">hemispheric</span> language areas. We studied cerebellar activation in five patients with congenital lesions of the left cerebral <span class="hlt">hemisphere</span> to assess…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25517886','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25517886"><span id="translatedtitle">Cerebral processing of proper and common nouns: Perception and production following left <span class="hlt">hemisphere</span> damage.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Seung-Yun; Van Lancker Sidtis, Diana</p> <p>2015-04-01</p> <p>The goal of this study was to further investigate <span class="hlt">hemispheric</span> specialization for proper and common nouns by examining the ability of individuals with left <span class="hlt">hemisphere</span> damage (LHD) to perceive and verbally reproduce famous names and matched common names compared with the performance of matched healthy controls (HC). Ten individuals with LHD due to stroke and 16 age- and education-matched HC completed recognition and production tasks of famous proper and common nouns. All tasks were designed as split-visual field experiments, modelled after the study done by Ohnesorge and Van Lancker. Results contribute to a better understanding of <span class="hlt">hemispheric</span> roles in perception and production of famous proper nouns, suggesting that (1) both <span class="hlt">hemispheres</span> can recognize famous proper nouns, possibly due to a right <span class="hlt">hemisphere</span> role in personal relevance and (2) production of proper nouns as well as common nouns is associated with left <span class="hlt">hemisphere</span>. PMID:25517886</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70047021','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70047021"><span id="translatedtitle">Foreword: contributions of Arctic PRISM to monitoring western <span class="hlt">hemispheric</span> shorebirds</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Skagen, Susan K.; Smith, Paul A.; Andres, Brad A.; Donaldson, Garry; Brown, Stephen</p> <p>2012-01-01</p> <p>Long-term monitoring of populations is of paramount importance to understanding responses of organisms to global environmental change and to evaluating whether conservation practices are yielding intended results through time (Wiens 2009). The population status of many shorebird species, the focus of this volume, remain poorly known. Long-distance migrant shorebirds have proven particularly difficult to monitor, in part because of their highly inaccessible regions. As migrant shorebirds travel the length of the <span class="hlt">hemisphere</span>, the congregate and disperse in ways that vary among species, locations, and years, presenting serious challenges to designing and implementing monitoring programs. Rigorous field and quantitative methods that estimate population size and monitor trends are vitally needed to direct and evaluate effective conservation measures. Many management efforts depend on unbiased population size estimates; for examples, the shorebird conservation plans for both Canada and the United States seek to restore populations to levels calculated for the 1970s based on the best information available from existing surveys. Further, federal wildlife agencies within the United States and Canada have mandates to understand the state of their nations' resources under various conventions for the protection of migratory birds. Accurate estimates of population size are vital statistics for a variety of conservation activities, such as prioritizing species for conservation action and setting management targets. Areas of essential habitat, such as those designated under the Western <span class="hlt">Hemisphere</span> Shorebird Reserve Network, the Important Bird Areas program of BirdLife Internationals and the National Audubon Society, or Canada's National Wildlife Areas program, are all evaluated on the basis of proportions of species' populations which they contain. The size, and trends in size, of a species' population are considered key information for assessing its vulnerability and subsequent</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70156770','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70156770"><span id="translatedtitle">Contributions of Arctic PRISM to monitoring western <span class="hlt">hemispheric</span> shorebirds</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Skagen, Susan K.; Smith, Paul A.; Andres, Brad A.; Donaldson, Garry; Brown, Stephen</p> <p>2012-01-01</p> <p>Long-term monitoring of populations is of paramount importance to understanding responses oforganisms to global environmental change and to evaluating whether conservation practices are yielding intended results through time (Wiens 2009). The population status of many shorebird species, the focus of this volume, remain poorly known. Long-distance migrant shorebirds have proven particularly difficult to monitor, in part because of their highly migratory nature and ranges that extend into highly inaccessible regions. As migrant shorebirds travel the length of the <span class="hlt">hemisphere</span>, they congregate and disperse in ways that vary among species, locations, and years, presenting serious challenges to designing and implementing monitoring programs. Rigorous field and quantitative methods that estimate population size and monitor trends are vitally needed to direct and evaluate effective conservation measures. Many management efforts depend on unbiased population size estimates; for example, the shorebird conservation plans for both Canada and the United States seek to restore populations to levels calculated for the 1970s based on the best information available from existing surveys. Further, federal wildlife agencies within the United States and Canada have mandates to understand the state of their nations' resources under various conventions for the protection of migratory birds. Accurate estimates of population size are vital statistics for a variety of conservation activities, such as prioritizing species for conservation action and setting management targets. Areas of essential habitat, such as those designated under the Western <span class="hlt">Hemisphere</span> Shorebird Reserve Network, the Important Bird Areas program of BirdLife International and the National Audubon Society, or Canada's National Wildlife Areas program, are all evaluated on the basis ofproportions of species' populations which they contain. The size, and trends in size, ofa species' population are considered key information</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1512267H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1512267H"><span id="translatedtitle">Geologic Map of the Northern <span class="hlt">Hemisphere</span> of Vesta</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hiesinger, Harald; Ruesch, Ottaviano; Blewett, Dave T.; Buczkowski, Debra L.; Scully, Jennifer; Williams, Dave A.; Aileen Yingst, R.; Russell, Chris T.; Raymond, Carol A.</p> <p>2013-04-01</p> <p>For more than a year, the NASA Dawn mission acquired Framing Camera (FC) images from orbit around Vesta. The surface of the asteroid was completely imaged [1] before Dawn left for its next target, the asteroid Ceres. In an early phase of the mission, the southern and equatorial regions were imaged, allowing the production of several geologic quadrangle maps [2]. During the second High Altitude Mapping Orbit (HAMO-2), the northern <span class="hlt">hemisphere</span> became illuminated and visible. Here we present the first geologic map of the northern vestan <span class="hlt">hemisphere</span>, from 21°N to 85°N, derived mainly from HAMO-2 observations. Detailed studies of specific geologic features within this <span class="hlt">hemisphere</span> are presented elsewhere [e.g., 3,4]. For our geologic map we used high-resolution FC images [5] with ~20 m/pixel from the Low Altitude Mapping Orbit (LAMO), which unfortunately only cover the southern part of the study area (21°N to 45°N). For areas farther north, LAMO images are supplemented with HAMO-2 images, which have a pixel scale of about 70 m/pixel. During the departure phase, images of the north pole area with even lower spatial resolutions were acquired. Due to observational constraints, considerable shadowing is present north of 75°. From these data, an albedo mosaic and a stereo-photogrammetric digital terrain model [6] was produced, which serve as basis for our geologic map. For the geologic mapping at a scale of 1:500,000, all data were incorporated into a Geographic Information System (ArcGIS). We have identified several geologic units within the study area, including cratered highland material (ch) and the Saturnalia Formation (Sf), which is characterized by large-scale ridges and troughs, presumably associated with the south polar Veneneia impact [7]. In addition, we mapped undifferentiated crater material (uc), discontinuous ejecta material (dem), and dark/bright crater material and dark/bright crater ray material (dc/bc and dcr/bcr). We will present a detailed description</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25709577','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25709577"><span id="translatedtitle"><span class="hlt">Hemispheric</span> differences in relational reasoning: novel insights based on an old technique.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vendetti, Michael S; Johnson, Elizabeth L; Lemos, Connor J; Bunge, Silvia A</p> <p>2015-01-01</p> <p>Relational reasoning, or the ability to integrate multiple mental relations to arrive at a logical conclusion, is a critical component of higher cognition. A bilateral brain network involving lateral prefrontal and parietal cortices has been consistently implicated in relational reasoning. Some data suggest a preferential role for the left <span class="hlt">hemisphere</span> in this form of reasoning, whereas others suggest that the two <span class="hlt">hemispheres</span> make important contributions. To test for a <span class="hlt">hemispheric</span> asymmetry in relational reasoning, we made use of an old technique known as visual half-field stimulus presentation to manipulate whether stimuli were presented briefly to one <span class="hlt">hemisphere</span> or the other. Across two experiments, 54 neurologically healthy young adults performed a visuospatial transitive inference task. Pairs of colored shapes were presented rapidly in either the left or right visual hemifield as participants maintained central fixation, thereby isolating initial encoding to the contralateral <span class="hlt">hemisphere</span>. We observed a left-<span class="hlt">hemisphere</span> advantage for encoding a series of ordered visuospatial relations, but both <span class="hlt">hemispheres</span> contributed equally to task performance when the relations were presented out of order. To our knowledge, this is the first study to reveal <span class="hlt">hemispheric</span> differences in relational encoding in the intact brain. We discuss these findings in the context of a rich literature on <span class="hlt">hemispheric</span> asymmetries in cognition. PMID:25709577</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4681927','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4681927"><span id="translatedtitle">A comparison of driving errors in patients with left or right <span class="hlt">hemispheric</span> lesions after stroke</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Park, Myoung-Ok</p> <p>2015-01-01</p> <p>[Purpose] The aim of this study was to compare the incidence of driving errors among patients with left or right <span class="hlt">hemispheric</span> lesions due to stroke. [Subjects and Methods] Thirty stroke patients participated in the study. Driving errors were assessed using a virtual reality driving simulator. [Results] Significant differences were shown in center line crossing frequency, accident rate, brake reaction time, total driving error scores, and overall driving safety between participants with left or right <span class="hlt">hemispheric</span> lesions. [Conclusion] Driving rehabilitation specialists should consider <span class="hlt">hemispheric</span> function when teaching driving skills to stroke survivors, because patients with lesions in the left or right <span class="hlt">hemispheres</span> after stroke show differences in driving skills. PMID:26696720</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4251456','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4251456"><span id="translatedtitle">An ERP investigation of the co-development of <span class="hlt">hemispheric</span> lateralization of face and word recognition</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dundas, Eva M.; Plaut, David C.; Behrmann, Marlene</p> <p>2014-01-01</p> <p>The adult human brain would appear to have specialized and independent neural systems for the visual processing of words and faces. Extensive evidence has demonstrated greater selectivity for written words in the left over right <span class="hlt">hemisphere</span>, and, conversely, greater selectivity for faces in the right over left <span class="hlt">hemisphere</span>. This study examines the emergence of these complementary neural profiles, as well as the possible relationship between them. Using behavioral and neurophysiological measures, in adults, we observed the standard finding of greater accuracy and a larger N170 ERP component in the left over right <span class="hlt">hemisphere</span> for words, and conversely, greater accuracy and a larger N170 in the right over the left <span class="hlt">hemisphere</span> for faces. We also found that, although children aged 7-12 years revealed the adult <span class="hlt">hemispheric</span> pattern for words, they showed neither a behavioral nor a neural <span class="hlt">hemispheric</span> superiority for faces. Of particular interest, the magnitude of their N170 for faces in the right <span class="hlt">hemisphere</span> was related to that of the N170 for words in their left <span class="hlt">hemisphere</span>. These findings suggest that the <span class="hlt">hemispheric</span> organization of face recognition and of word recognition do not develop independently, and that word lateralization may precede and drive later face lateralization. A theoretical account for the findings, in which competition for visual representations unfolds over the course of development, is discussed. PMID:24933662</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21260232','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21260232"><span id="translatedtitle">A Versatile <span class="hlt">Hemispherical</span> Great Area X-ray Detector for Synchrotron Radiation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Figueroa, Rodolfo; Belmar, Felipe</p> <p>2009-01-29</p> <p>This work presents an X-ray detector with fullerene C60 semi spherical geometry constituted by a set of small cylindrical proportional counter units with needles anodes, which are located in the surface of an <span class="hlt">hemispherical</span> plastic support. The sample to be analyzed is placed on the center of the <span class="hlt">hemisphere</span> base. The radiation may enter by one of its flanks or through the <span class="hlt">hemisphere</span> top. The <span class="hlt">hemispherical</span> zone that exists between the holder sample base and the proportional counters can be vacuumed, aired or filled with counter gas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24695717','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24695717"><span id="translatedtitle">Effective connectivity reveals right-<span class="hlt">hemisphere</span> dominance in audiospatial perception: implications for models of spatial neglect.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dietz, Martin J; Friston, Karl J; Mattingley, Jason B; Roepstorff, Andreas; Garrido, Marta I</p> <p>2014-04-01</p> <p>Detecting the location of salient sounds in the environment rests on the brain's ability to use differences in sounds arriving at both ears. Functional neuroimaging studies in humans indicate that the left and right auditory hemispaces are coded asymmetrically, with a rightward attentional bias that reflects spatial attention in vision. Neuropsychological observations in patients with spatial neglect have led to the formulation of two competing models: the orientation bias and right-<span class="hlt">hemisphere</span> dominance models. The orientation bias model posits a symmetrical mapping between one side of the sensorium and the contralateral <span class="hlt">hemisphere</span>, with mutual inhibition of the ipsilateral <span class="hlt">hemisphere</span>. The right-<span class="hlt">hemisphere</span> dominance model introduces a functional asymmetry in the brain's coding of space: the left <span class="hlt">hemisphere</span> represents the right side, whereas the right <span class="hlt">hemisphere</span> represents both sides of the sensorium. We used Dynamic Causal Modeling of effective connectivity and Bayesian model comparison to adjudicate between these alternative network architectures, based on human electroencephalographic data acquired during an auditory location oddball paradigm. Our results support a <span class="hlt">hemispheric</span> asymmetry in a frontoparietal network that conforms to the right-<span class="hlt">hemisphere</span> dominance model. We show that, within this frontoparietal network, forward connectivity increases selectively in the <span class="hlt">hemisphere</span> contralateral to the side of sensory stimulation. We interpret this finding in light of hierarchical predictive coding as a selective increase in attentional gain, which is mediated by feedforward connections that carry precision-weighted prediction errors during perceptual inference. This finding supports the disconnection hypothesis of unilateral neglect and has implications for theories of its etiology. PMID:24695717</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AJ....151...70D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AJ....151...70D"><span id="translatedtitle">Systematic Regularity of <span class="hlt">Hemispheric</span> Sunspot Areas Over the Past 140 Years</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deng, L. H.; Xiang, Y. Y.; Qu, Z. N.; An, J. M.</p> <p>2016-03-01</p> <p>Solar magnetic activity varies with time in the two <span class="hlt">hemispheres</span> in different ways. The <span class="hlt">hemispheric</span> interconnection of solar activity phenomena provides an important clue to understanding the dynamical behavior of solar dynamo actions. In this paper, several analysis approaches are proposed to analyze the systematic regularity of <span class="hlt">hemispheric</span> asynchronism and amplitude asymmetry of long-term sunspot areas during solar cycles 9-24. It is found that, (1) both the <span class="hlt">hemispheric</span> asynchronism and the amplitude asymmetry of sunspot areas are prevalent behaviors and are not anomalous, but the <span class="hlt">hemispheric</span> asynchronism exhibits a much more regular behavior than the amplitude asymmetry; (2) the phase-leading <span class="hlt">hemisphere</span> returns back to the identical <span class="hlt">hemisphere</span> every 8 solar cycles, and the secular periodic pattern of <span class="hlt">hemispheric</span> phase differences follows 3 (south leading) + 5 (north leading) solar cycles, which probably corresponds to the Gleissberg cycle; and (3) the pronounced periodicities of (absolute and normalized) asymmetry indices and lines of synchronization (LOSs) are not identical: the significant periodic oscillations are 80.65 ± 6.31, 20.91 ± 0.40, and 13.45 ± 0.16 years for the LOS values, and 51.34 ± 2.48, 8.83/8.69 ± 0.07, and 3.77 ± 0.02 years for the (absolute and normalized) asymmetry indices. The analysis results improve our knowledge on the <span class="hlt">hemispheric</span> interrelation of solar magnetic activity and may provide valuable constraints for solar dynamo models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820028329&hterms=flask&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dflask','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820028329&hterms=flask&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dflask"><span id="translatedtitle">Trends of atmospheric methane in the Southern <span class="hlt">Hemisphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fraser, P. J.; Khalil, M. A. K.; Rasmussen, R. A.; Crawford, A. J.</p> <p>1981-01-01</p> <p>Atmospheric observations spanning the past three years show that methane increased at 1.2 (plus or minus 0.3)% per year at Cape Grim in Tasmania (41 deg S). This rate of increase can be compared to the 1.9 (plus or minus 0.4)% per year observed at Cape Meares in Oregon (45 deg N) over the past two years. Over the corresponding period the concentration at Cape Grim increased by 1.4 (plus or minus 0.4)% per year. The Southern <span class="hlt">Hemisphere</span> data also suggest seasonal variations with minimum concentrations in March and maximum in September. These results are based on 26 large-volume stable air samples collected cryogenically in stainless steel flasks and 75 smaller-volume air samples collected in glass flasks, all analyzed by a gas chromatograph using a flame ionization detector.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015GeoRL..42.4964K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015GeoRL..42.4964K&link_type=ABSTRACT"><span id="translatedtitle">Black carbon aerosol-induced Northern <span class="hlt">Hemisphere</span> tropical expansion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kovilakam, Mahesh; Mahajan, Salil</p> <p>2015-06-01</p> <p>Global climate models (GCMs) underestimate the observed trend in tropical expansion. Recent studies partly attribute it to black carbon (BC) aerosols, which are poorly represented in GCMs. We conduct a suite of idealized experiments with the Community Atmosphere Model version 4 coupled to a slab ocean model forced with increasing BC concentrations covering a large swath of the estimated range of current BC radiative forcing while maintaining their spatial distribution. The Northern <span class="hlt">Hemisphere</span> (NH) tropics expand poleward nearly linearly as BC radiative forcing increases (0.7° W-1 m2), indicating that a realistic representation of BC could reduce GCM biases. We find support for the mechanism where BC-induced midlatitude tropospheric heating shifts the maximum meridional tropospheric temperature gradient poleward resulting in tropical expansion. We also find that the NH poleward tropical edge is nearly linearly correlated with the location of the Intertropical Convergence Zone, which shifts northward in response to increasing BC.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Sci...347..988S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Sci...347..988S"><span id="translatedtitle">Atlantic and Pacific multidecadal oscillations and Northern <span class="hlt">Hemisphere</span> temperatures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steinman, Byron A.; Mann, Michael E.; Miller, Sonya K.</p> <p>2015-02-01</p> <p>The recent slowdown in global warming has brought into question the reliability of climate model projections of future temperature change and has led to a vigorous debate over whether this slowdown is the result of naturally occurring, internal variability or forcing external to Earth’s climate system. To address these issues, we applied a semi-empirical approach that combines climate observations and model simulations to estimate Atlantic- and Pacific-based internal multidecadal variability (termed “AMO” and “PMO,” respectively). Using this method, the AMO and PMO are found to explain a large proportion of internal variability in Northern <span class="hlt">Hemisphere</span> mean temperatures. Competition between a modest positive peak in the AMO and a substantially negative-trending PMO are seen to produce a slowdown or “false pause” in warming of the past decade.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMPP11A1796A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMPP11A1796A"><span id="translatedtitle">Northern <span class="hlt">Hemisphere</span> moisture variability during the Last Glacial period</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Asmerom, Y.; Polyak, V. J.; Lachniet, M. S.</p> <p>2013-12-01</p> <p> change in Northern <span class="hlt">Hemisphere</span> summer insolation (insolation), similar to other Northern <span class="hlt">Hemisphere</span> data, such as the strength of the East Asian summer monsoon as recorded in the Hulu speleothem, although the match to the East Asian monsoon is inverse. The much diminished expression of stadials and interstadials and secular variations in the effective moisture proxy data that match insolation seem to be <span class="hlt">hemispherical</span> in scale. In humid settings, such as east Asia monsoon regions, warm temperatures lead to northward shift of the ITCZ and increase in the strength of the Asian monsoon, while in the desert SW any increase in the strength in the North American monsoon is counterbalanced by decrease in winter moisture due to the northward shift of the polar jet stream and more importantly, the onset of more evaporative conditions. In contrast to the large and rapid shifts seen in the Greenland ice core data and the apparent shift in position in air masses, as indicated by our δ18O data, large-scale changes in moisture regimes in the Northern <span class="hlt">Hemisphere</span> seem to be driven by changes in insolation. Locations that are sensitive to small changes in atmospheric pressure and/or sea surface temperature gradients may be the exception.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050172162','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050172162"><span id="translatedtitle">Cassini VIMS Preliminary Exploration of Titan's Surface <span class="hlt">Hemispheric</span> Albedo Dichotomy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nelson, R. M.; Brown, R. H.; Hapke, B. W.; Smythe, W. D.; Kamp, L.; Boryta, M.; Baines, K. H.; Bellucci, G.; Bibring, J.-P.; Buratti, B. J.</p> <p>2005-01-01</p> <p>We present preliminary evidence that suggests a <span class="hlt">hemispheric</span> albedo dichotomy on Titan, the largest planetary satellite in the Solar System. We have also studied the photometric properties of several dark circular features on Titan's surface to test if they might be of impact origin. The evidence is derived from photometric analysis of selected surface regions taken at different Titanian longitudes and solar phase angles using images from the Cassini Saturn Orbiter Visual and Infrared Mapping Spectrometer (VIMS). The VIMS instrument is able to image Titan's surface at spectral windows (e.g. 2.02 microns) in its atmosphere where methane, the principal atmospheric absorber is transparent. Additional information is included in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/of/2001/0276/report.pdf','USGSPUBS'); return false;" href="http://pubs.usgs.gov/of/2001/0276/report.pdf"><span id="translatedtitle">Socioeconomic and environmental impacts of landslides in the Western <span class="hlt">Hemisphere</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Schuster, Robert L.; Highland, Lynn M.</p> <p>2001-01-01</p> <p>In spite of improvements in recognition, prediction, mitigative measures, and warning systems, economic losses and casualties due to landslides in the Western <span class="hlt">Hemisphere</span> appear to be growing as a result of increasing development of landslide-prone areas due to population pressures. This paper notes outstanding examples of socioeconomic losses in the Americas. Landslides impact the following elements of the natural environment: (1) the topography/morphology of both the subaerial and submarine surfaces of the Earth, (2) rivers, streams, forests, and grasslands, and (3) habitats of native fauna, both on the Earth?s surface and in its streams and oceans. Environmental disturbances are results of general tendency toward degradation of the Earth?s surface by gravitational mass wasting and erosion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPSC...10..259T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPSC...10..259T"><span id="translatedtitle">A quasi-<span class="hlt">hemispheric</span> model of the Hermean's magnetic field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thebault, E.; Oliveira, J.; Langlais, B.; Amit, H.</p> <p>2015-10-01</p> <p>We analyse and process magnetic field measurements provided by the MErcury Surface, Space ENvironment, Geochemistry, and Ranging (MESSENGER) mission. The vect or magnetic field measurements are modelled with a dedicated regional scheme expanded in space and in time. Compared to the widely used global Spherical Harmonics (SH), the regional approach is particularly well suited because the partial and quasi <span class="hlt">hemispheric</span> distribution of the MESSENGER data represents no major numerical difficulty. We confirm that the internal magnetic field of Mercury is mostly axisymmetric with a magnetic equator shifted northward. However, we also observe a time dependency in the model that is at present hardly explained only by time variations of the external magnetic fields. We present the major spatial and temporal structures shown by the regional model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/10990381','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10990381"><span id="translatedtitle">Cementless <span class="hlt">hemispheric</span> acetabular component in total hip replacement.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Weber, D; Schaper, L A; Pomeroy, D L; Badenhausen, W E; Curry, J I; Smith, M W; Suthers, K E</p> <p>2000-01-01</p> <p>A series of 198 total hip arthroplasties was performed using a porous-coated, <span class="hlt">hemispheric</span> press-fit cup. One hundred and twenty-seven cups were available for clinical and radiological examination at mean follow-up of 10.6 years. The mean age at the index procedure was 61.2 years. The mean Harris hip score at final follow-up was 89.8. Three cups were revised for aseptic loosening and two liners were changed for eccentric wear and pelvic osteolysis. Nine additional patients showed mild or suspected osteolysis. Two cups were rated "fibrous" stable. There was no correlation between additional screw fixation of the press-fit cup and osteolysis or revision. PMID:10990381</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005ApPhL..86i4105Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005ApPhL..86i4105Z&link_type=ABSTRACT"><span id="translatedtitle">Optimal energy resolution of a <span class="hlt">hemispherical</span> analyzer with virtual entry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zouros, T. J. M.; Benis, E. P.</p> <p>2005-02-01</p> <p>For an ideal <span class="hlt">hemispherical</span> deflector analyzer (HDA) utilizing a virtual entry aperture whose size is controlled by an injection lens, the "slit" and angular contributions to the overall base resolution RB are not independent, but constrained by the Helmholtz-Lagrange law. Thus, RB becomes a function of the linear lens magnification ∣ML∣ and has a minimum, RBo¯≡RB(∣ML∣o), at the optimal magnification ∣ML∣=∣ML∣o. RBo¯ and ∣ML∣o are shown to be analytic expressions of basic experimental parameters. RBo¯ is thus the ultimate resolution that can be attained in this case. The generality and simplicity of this result should be very helpful in the efficient design and performance evaluation of any modern HDA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.3897B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.3897B"><span id="translatedtitle">Annular modes and apparent eddy feedbacks in the Southern <span class="hlt">Hemisphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Byrne, Nicholas J.; Shepherd, Theodore G.; Woollings, Tim; Plumb, R. Alan</p> <p>2016-04-01</p> <p>Lagged correlation analysis is often used to infer intraseasonal dynamical effects but is known to be affected by nonstationarity. We highlight a pronounced quasi 2 year peak in the anomalous zonal wind and eddy momentum flux convergence power spectra in the Southern <span class="hlt">Hemisphere</span>, which is prima facie evidence for nonstationarity. We then investigate the consequences of this nonstationarity for the Southern Annular Mode and for eddy momentum flux convergence. We argue that positive lagged correlations previously attributed to the existence of an eddy feedback are more plausibly attributed to nonstationary interannual variability external to any potential feedback process in the midlatitude troposphere. The findings have implications for the diagnosis of feedbacks in both models and reanalysis data as well as for understanding the mechanisms underlying variations in the zonal wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860033250&hterms=skills&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dskills','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860033250&hterms=skills&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dskills"><span id="translatedtitle">Forecast skill impact of drifting buoys in the Southern <span class="hlt">Hemisphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kalnay, E.; Atlas, R.; Baker, W.; Halem, M.</p> <p>1984-01-01</p> <p>Two analyses are performed to evaluate the effect of drift buoys and the FGGE's special observing system (SOS) on forecasting. The FGGE analysis utilizes all level II-b conventional and special data, and the Nosat analysis employs only surface and conventional upper air data. Twelve five-day forecasts are produced from these data. An additional experiment utilizing the FGGE data base minus buoys data, and the Nosat data base including buoys data is being conducted. The forecasts are compared and synoptic evaluation of the effect of buoys data is described. The results reveal that the FGGE data base with the SOS significantly improves forecasting in the Southern <span class="hlt">Hemisphere</span> and the loss of buoys data does not have a great effect on forecasting. The Nosat data has less impact on forecasting; however, the addition of buoys data provides an improvement in forecast skills.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990088748&hterms=MOLA&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DMOLA','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990088748&hterms=MOLA&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DMOLA"><span id="translatedtitle">Mola's First Observations of the Southern <span class="hlt">Hemisphere</span> Topography of Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, David E.; Zuber, M. T.</p> <p>1999-01-01</p> <p>Towards the end of February 1999, the Mars Global Surveyor (MGS) spacecraft is expected to enter a near-circular polar orbit around Mars at an altitude of about 400 km. At this time the Mars Orbiter Laser Altimeter (MOLA) will begin near-continuous operation and acquire topography of the full planet. The initial areas of study will be concentrated in the southern <span class="hlt">hemisphere</span> with particular interest in the polar region near the targeted landing site of the Mars Polar Lander. In addition to topography, MOLA matched filter pulse width data will be used to assess foot-print-scale surface roughness in the region. Such observations will also be applied in future studies for assessment of the Mars '01 landing site in the latitude range 15 degrees south to 5 degrees north.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA00957&hterms=MOLA+Mars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DMOLA%2B%252B%2BMars','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA00957&hterms=MOLA+Mars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DMOLA%2B%252B%2BMars"><span id="translatedtitle">MGS Mars Orbiter Laser (MOLA) Surface Topography of Northern <span class="hlt">Hemisphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1997-01-01</p> <p>A 'picket fence' rendition of surface topography in the northern <span class="hlt">hemisphere</span> of Mars from the Mars Orbiter Laser Altimeter (MOLA). The profile was obtained during the Mars Global Surveyor Capture Orbit Calibration Pass on September 15, 1997. The profile runs from 73oN to 10oS latitude and passes through the topographically subdued northern plains, the western part of the Elysium volcanic province, which shows 3 miles (5 kilometers) of relief, and the chaotic 'dichotomy' boundary between the northern plains and ancient southern highlands. The MOLA profile is approximately 3000 miles (5000 kilometers) long and has a resolution on the surface of 1000 feet (330 meters) and a vertical resolution of approximately 3 feet (1 meter).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18662751','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18662751"><span id="translatedtitle">K.M. Bykov and transfer between the <span class="hlt">hemispheres</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Glickstein, Mitchell; Berlucchi, Giovanni</p> <p>2008-09-30</p> <p>Experiments in the laboratory of Roger Sperry showed that section of the corpus callosum blocks the normally strong transfer of information between the two <span class="hlt">hemispheres</span> of the brain. In some of the papers from Sperry's lab, work by Bykov in Pavlov's lab was cited, since he appeared to have found similar results earlier. At the time, the only source on Bykov's experiment that was easily available was an abstract in a German journal. Although Bykov was the author of the paper, he did not write the abstract. The author of the abstract was Mark Serejski. Recently we obtained a copy of Bykov's original article in Russian, and arranged for it to be translated into English. The full article makes it clear that the abstract was somewhat misleading both in the methods and the results of Bykov's study. Here we present an English translations of Bykov's paper and the Serejski abstract, along with comments on the discrepancies between the two. PMID:18662751</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27078569','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27078569"><span id="translatedtitle">Northern <span class="hlt">Hemisphere</span> hydroclimate variability over the past twelve centuries.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ljungqvist, Fredrik Charpentier; Krusic, Paul J; Sundqvist, Hanna S; Zorita, Eduardo; Brattström, Gudrun; Frank, David</p> <p>2016-04-01</p> <p>Accurate modelling and prediction of the local to continental-scale hydroclimate response to global warming is essential given the strong impact of hydroclimate on ecosystem functioning, crop yields, water resources, and economic security. However, uncertainty in hydroclimate projections remains large, in part due to the short length of instrumental measurements available with which to assess climate models. Here we present a spatial reconstruction of hydroclimate variability over the past twelve centuries across the Northern <span class="hlt">Hemisphere</span> derived from a network of 196 at least millennium-long proxy records. We use this reconstruction to place recent hydrological changes and future precipitation scenarios in a long-term context of spatially resolved and temporally persistent hydroclimate patterns. We find a larger percentage of land area with relatively wetter conditions in the ninth to eleventh and the twentieth centuries, whereas drier conditions are more widespread between the twelfth and nineteenth centuries. Our reconstruction reveals that prominent seesaw patterns of alternating moisture regimes observed in instrumental data across the Mediterranean, western USA, and China have operated consistently over the past twelve centuries. Using an updated compilation of 128 temperature proxy records, we assess the relationship between the reconstructed centennial-scale Northern <span class="hlt">Hemisphere</span> hydroclimate and temperature variability. Even though dry and wet conditions occurred over extensive areas under both warm and cold climate regimes, a statistically significant co-variability of hydroclimate and temperature is evident for particular regions. We compare the reconstructed hydroclimate anomalies with coupled atmosphere-ocean general circulation model simulations and find reasonable agreement during pre-industrial times. However, the intensification of the twentieth-century-mean hydroclimate anomalies in the simulations, as compared to previous centuries, is not supported</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.5242O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.5242O"><span id="translatedtitle">Stratospheric influence on Northern <span class="hlt">Hemisphere</span> winter climate variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ouzeau, Gaelle; Douville, Herve; Saint Martin, David</p> <p>2010-05-01</p> <p>Despite significant improvements in observing and data assimilation systems, long-range dynamical forecasting remains a difficult challenge for the climate modelling community. The skill of operational seasonal forecasting systems is particularly poor in the northern extratropics where seas surface temperature (SST) has a weaker influence than in the Tropics. It is therefore relevant to look for additional potential sources of long-range climate predictability in the stratosphere using ensembles of global atmospheric simulations. Besides a control experiment where the ARPEGE-Climat model is only driven by SST, parallel simulations have been performed in which an additional control on climate variability has been accounted for through the nudging of the northern extratropical stratosphere towards the ERA40 reanalysis. Though idealized, this original experiment design allows us to compare the relative contribution of the lower and upper boundary forcings on the simulated tropospheric variability. Results show that the stratospheric nudging improves the climatology and interannual variability of the mid-latitude troposphere, especially in winter in the Northern <span class="hlt">Hemisphere</span>. Major impacts are found in particular on the simulation of the Arctic and North Atlantic oscillations (AO and NAO). Case studies were carried out for the 1976-1977 and 1988-1989 winters, corresponding to extreme phases of the AO. Results confirm the robustness of the positive impact of the nudging, especially for winter 1976-1977 corresponding to relatively weak SST anomalies in the tropical Pacific. A sensitivity study to the model resolution shows that a well-resolved stratosphere is not necessary for the nudging to be efficient. Besides seasonal mean results, analysis of the day-to-day variability in winter allowed us to better understand the stratospheric polar vortex influence on the tropospheric circulation in the Northern <span class="hlt">Hemisphere</span> mid-latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18580945','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18580945"><span id="translatedtitle">Mega-impact formation of the Mars <span class="hlt">hemispheric</span> dichotomy.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Marinova, Margarita M; Aharonson, Oded; Asphaug, Erik</p> <p>2008-06-26</p> <p>The Mars <span class="hlt">hemispheric</span> dichotomy is expressed as a dramatic difference in elevation, crustal thickness and crater density between the southern highlands and northern lowlands (which cover approximately 42% of the surface). Despite the prominence of the dichotomy, its origin has remained enigmatic and models for its formation largely untested. Endogenic degree-1 convection models with north-south asymmetry are incomplete in that they are restricted to simulating only mantle dynamics and they neglect crustal evolution, whereas exogenic multiple impact events are statistically unlikely to concentrate in one <span class="hlt">hemisphere</span>. A single mega-impact of the requisite size has not previously been modelled. However, it has been hypothesized that such an event could obliterate the evidence of its occurrence by completely covering the surface with melt or catastrophically disrupting the planet. Here we present a set of single-impact initial conditions by which a large impactor can produce features consistent with the observed dichotomy's crustal structure and persistence. Using three-dimensional hydrodynamic simulations, large variations are predicted in post-impact states depending on impact energy, velocity and, importantly, impact angle, with trends more pronounced or unseen in commonly studied smaller impacts. For impact energies of approximately (3-6) x 10(29) J, at low impact velocities (6-10 km s(-1)) and oblique impact angles (30-60 degrees ), the resulting crustal removal boundary is similar in size and ellipticity to the observed characteristics of the lowlands basin. Under these conditions, the melt distribution is largely contained within the area of impact and thus does not erase the evidence of the impact's occurrence. The antiquity of the dichotomy is consistent with the contemporaneous presence of impactors of diameter 1,600-2,700 km in Mars-crossing orbits, and the impact angle is consistent with the expected distribution. PMID:18580945</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12291093','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12291093"><span id="translatedtitle">Advocacy in the Western <span class="hlt">Hemisphere</span> Region: some FPA success stories.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Andrews, D J</p> <p>1996-01-01</p> <p>The International Planned Parenthood Federation's Vision 2000 Strategic Plan has emphasized advocacy and the training of family planning associations (FPAs) in the Western <span class="hlt">Hemisphere</span> region. During the summer of 1995 training programs in advocacy leadership management were sponsored for six FPAs in the Bahamas, Suriname, Belize, Colombia, Honduras, and Brazil. At the Western <span class="hlt">Hemisphere</span> Regional Council Meeting in September 1995 awards were presented to FPAs for media outstanding projects. These FPAs used outreach to the community to promote the goals of Vision 2000. The Bahamas FPA won the Rosa Cisneros Award for articles published in a magazine that is distributed in primary and secondary schools and deals with the activities, achievements, and opinions of students. Issues include: love, relationships, responsibility, and teen pregnancy. A weekly television talk show also addresses the issues facing youth including education, music, community work, sexuality, pregnancy, and the relationship between teenagers and adults. The Family Planning Association of Honduras was also nominated for the award for a radio show on the health of mothers and children, the problems of adolescents, and FP. The newspaper Tiempo received the award for feature articles on social issues and FP. In 1994 the Association distributed thousands of booklets on contraceptives as well as fliers on vasectomy, female sterilization, oral contraceptives, IUDs, condoms, responsible parenthood, high-risk pregnancy, vaginal cytology, and cervical cancer. Similar posters were placed in hospitals and health centers, in 1997 FP posts, and 400 commercial outlets. The Family Planning Association of Suriname also carried out an impressive advocacy program during the period of 1968-93 with the goals of establishing a balance between population growth and the available resources to achieve well-being with regard to education, health care, nutrition, and housing. PMID:12291093</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3358327','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3358327"><span id="translatedtitle">Reduction in Inter-<span class="hlt">Hemispheric</span> Connectivity in Disorders of Consciousness</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ovadia-Caro, Smadar; Nir, Yuval; Soddu, Andrea; Ramot, Michal; Hesselmann, Guido; Vanhaudenhuyse, Audrey; Dinstein, Ilan; Tshibanda, Jean-Flory L.; Boly, Melanie; Harel, Michal; Laureys, Steven; Malach, Rafael</p> <p>2012-01-01</p> <p>Clinical diagnosis of disorders of consciousness (DOC) caused by brain injury poses great challenges since patients are often behaviorally unresponsive. A promising new approach towards objective DOC diagnosis may be offered by the analysis of ultra-slow (<0.1 Hz) spontaneous brain activity fluctuations measured with functional magnetic resonance imaging (fMRI) during the resting-state. Previous work has shown reduced functional connectivity within the “default network”, a subset of regions known to be deactivated during engaging tasks, which correlated with the degree of consciousness impairment. However, it remains unclear whether the breakdown of connectivity is restricted to the “default network”, and to what degree changes in functional connectivity can be observed at the single subject level. Here, we analyzed resting-state inter-<span class="hlt">hemispheric</span> connectivity in three homotopic regions of interest, which could reliably be identified based on distinct anatomical landmarks, and were part of the “Extrinsic” (externally oriented, task positive) network (pre- and postcentral gyrus, and intraparietal sulcus). Resting-state fMRI data were acquired for a group of 11 healthy subjects and 8 DOC patients. At the group level, our results indicate decreased inter-<span class="hlt">hemispheric</span> functional connectivity in subjects with impaired awareness as compared to subjects with intact awareness. Individual connectivity scores significantly correlated with the degree of consciousness. Furthermore, a single-case statistic indicated a significant deviation from the healthy sample in 5/8 patients. Importantly, of the three patients whose connectivity indices were comparable to the healthy sample, one was diagnosed as locked-in. Taken together, our results further highlight the clinical potential of resting-state connectivity analysis and might guide the way towards a connectivity measure complementing existing DOC diagnosis. PMID:22629375</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36.2189M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36.2189M"><span id="translatedtitle">Polar mesosphere summer echoes (PMSE) a southern <span class="hlt">hemisphere</span> perspective</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morris, R. J.; Murphy, D. J.; Klekociuk, A. R.; Holdsworth, D. A.</p> <p></p> <p>The existence of Polar Mesosphere Summer Echoes PMSE in the Southern <span class="hlt">Hemisphere</span> SH has recently been confirmed using HF radar Ogawa et al 2002 MST radar Morris et al 2004 and a Dynasonde Jarvis et al 2005 following earlier observations using MST radar Woodman et al 1999 These studies spanned the geographic latitudes 62 1 r S Machu Picchu 68 6 r S Davis 69 0 r S Syowa and 75 5 r S Halley Bay The emerging array of SH SuperDARN radars provide an opportunity to extend the spatial coverage of PMSE observations An understanding of the occurrence and intensity of PMSE against latitude in the SH is needed to facilitate a comparison with the better spatial coverage of Northern <span class="hlt">Hemisphere</span> NH PMSE observations Such a comparison will contribute to the ongoing debate as to whether PMSE can provide a proxy for mesosphere temperature and thus shed light on the existence of any interhemispheric asymmetry or otherwise in the polar mesosphere regions The argument for different polar mesosphere environments spawned in part by the reported lack of SH PMSE observations Recent PMSE reflectivity and intensity results from Davis 68 6 r S and Andenes 69 0 r N are given The characteristics and morphology of PMSE events above these Antarctic stations are considered in the context of the thermal and dynamical state of the mesosphere as deduced from satellite i e SABER and AURA and radar i e MF and MST observations respectively A brief account of recent coincident PMSE MST radar and Polar Mesospheric Cloud PMC</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24929474','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24929474"><span id="translatedtitle">Object and space perception - is it a matter of <span class="hlt">hemisphere</span>?</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schintu, Selene; Hadj-Bouziane, Fadila; Dal Monte, Olga; Knutson, Kristine M; Pardini, Matteo; Wassermann, Eric M; Grafman, Jordan; Krueger, Frank</p> <p>2014-08-01</p> <p>In the 1980s, following Newcombe's observations, Ungerleider and Mishkin put forward the functional subdivision of the visual system into a ventral stream dedicated to object perception and a dorsal stream dedicated to space perception. Ten years after this discovery, the perception-action model re-defined the dorsal stream as responsible for non-conscious visual guidance, and most recently a tripartition has been suggested to account for a variety of visuospatial functions. Here, we investigated the neural underpinnings of object and space perception by combining the administration of the Visual Object Space Perception (VOSP) battery with a voxel-based lesion symptom mapping (VLSM) approach in a large sample of patients with penetrating traumatic brain injury (pTBI). First, our results provided new support for the complementary role of both <span class="hlt">hemispheres</span> in object recognition. The right lateral occipital complex was found to be critical in early perceptual discrimination, whereas more anterior temporal and frontal regions in the left <span class="hlt">hemisphere</span> were found to be critical in more complex forms of object discrimination and recognition. Second, our findings confirmed that space perception depended on the integrity of the right inferior parietal lobule (IPL) and revealed that a network linking the right IPL with the right premotor cortex was critical for the perception of spatial relationships in both 2D and 3D representations. Taken together, our results supported the functional subdivision of the visual system and shed new light on the specific processes involved along both the dorsal and the ventral streams. PMID:24929474</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.4392B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.4392B"><span id="translatedtitle">Mechanism of secular increasing of mean gravity in Northern <span class="hlt">hemisphere</span> and secular decreasing of mean gravity in Southern <span class="hlt">hemisphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barkin, Yu. V.; Ferrandiz, J. M.</p> <p>2009-04-01</p> <p> phenomena as cyclicity and synchronism of planetary natural processes, inversion of activity of natural processes in opposite <span class="hlt">hemispheres</span>. Numerous confirmations give the extensive data of every possible geophysical observations. The phenomenon of synchronism in annual variations of activity of various natural processes is rather brightly expressed - their phases are precisely synchronized, and the periods of extreme activity (or passivity) fall to February - March or August - September. In daily variations of natural processes similar laws are observed. Here we speak about modern processes, but similar laws take place in various time scales, including geological. In the given report we shall concentrate on the analysis of possible secular variations of a gravity at displacement of an external core (of its centre of mass) relatively to the elastic mantle. The analysis has shown, that gravitational influence of displaced superfluous mass of the core are a major factor of secular variations of a gravity. However the displaced core causes directed redistribution of atmospheric masses from a southern <span class="hlt">hemisphere</span> in northern, and also complex slow redistribution of oceanic masses. Increase of loading of atmospheric and oceanic masses on an elastic crust of northern <span class="hlt">hemisphere</span> results in its slow lowering. Return processes should observed in a southern <span class="hlt">hemisphere</span>. All listed factors, certainly, directly influence variations of a gravity. In a more comprehensive sense redistribution of all fluid masses, including climatic character also result in changes of a gravity. <span class="hlt">Hemispheres</span> mean secular trends of gravity. For an estimation of a role of factors of redistribution of air and fluid masses in variations of a gravity the point model of redistribution of masses of the Earth (Barkin, 2001), obtained very effective applications at studying of fundamental problems of geodynamics, has been used. Let's emphasize, that the Earth is active dynamic object at which activity in the certain</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.7879H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.7879H"><span id="translatedtitle">Determination of the Annual Shading Potential of Salix Purpurea Coppice using <span class="hlt">Hemispherical</span> Photographs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holzapfel, G.; Weihs, P.; Stockreiter, L.; Hoffmann, E.</p> <p>2012-04-01</p> <p>The European Water Framework Directive (WFD) aims to achieve a good ecological potential and good surface water chemical status for all surface waters. Widely constant shading with riparian vegetation is the potential natural <span class="hlt">plant</span> cover condition and plays a key role by the implementation of the WFD. The shading effect of vegetation is considered to be particularly relevant for small and medium sized rivers with slow flow velocity. Soil Bioengineering measures effect technical (e.g. soil protection), ecological and socio-economical issues on river systems. Positive ecological effects are based on the development of the used <span class="hlt">plants</span> and result among others in shading of the water body. Natural bank vegetation provides very important niches for terrestrial and aquatic stages and reduces the incident solar radiation up to 95%. Consequently large riparian wooded areas form a microclimate that leads to a decrease of water temperature or prevent an increase. They even reduce evaporation and increase the relative air humidity which contributes to reducing water temperature and enlarges the oxygen uptake capacity. Accordingly the daily variations of temperature and those of oxygen content are definitely lower in vegetated areas. This issue is especially important considering climate change scenarios with increasing water temperatures. From an ecological point of view it is essential to quantify the processes. There are different ways to characterize densities of vegetation. Most of them - such as the method by Braun-Blanquet and Londo - rely on estimations of the dominance of species. Applying this kind of procedures on riparian vegetation result in uncertainties due to the strong variations in height and densities. <span class="hlt">Hemispherical</span> photographs are a standardized method in forest ecology under more or less uniform forest stand conditions. However it is now hardly used for riparian vegetation stands. Questions that will be addressed are the determination of annual stand</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26090853','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26090853"><span id="translatedtitle">Multigene Phylogeography of Bactrocera caudata (Insecta: Tephritidae): Distinct Genetic Lineages in Northern and Southern <span class="hlt">Hemispheres</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yong, Hoi-Sen; Lim, Phaik-Eem; Tan, Ji; Song, Sze-Looi; Suana, I Wayan; Eamsobhana, Praphathip</p> <p>2015-01-01</p> <p>Bactrocera caudata is a pest of pumpkin flower. Specimens of B. caudata from the northern <span class="hlt">hemisphere</span> (mainland Asia) and southern <span class="hlt">hemisphere</span> (Indonesia) were analysed using the partial DNA sequences of the nuclear 28S rRNA and internal transcribed spacer region 2 (ITS-2) genes, and the mitochondrial cytochrome c oxidase subunit I (COI), cytochrome c oxidase subunit II (COII) and 16S rRNA genes. The COI, COII, 16S rDNA and concatenated COI+COII+16S and COI+COII+16S+28S+ITS-2 nucleotide sequences revealed that B. caudata from the northern <span class="hlt">hemisphere</span> (Peninsular Malaysia, East Malaysia, Thailand) was distinctly different from the southern <span class="hlt">hemisphere</span> (Indonesia: Java, Bali and Lombok), without common haplotype between them. Phylogenetic analysis revealed two distinct clades (northern and southern <span class="hlt">hemispheres</span>), indicating distinct genetic lineage. The uncorrected 'p' distance for the concatenated COI+COII+16S nucleotide sequences between the taxa from the northern and southern <span class="hlt">hemispheres</span> ('p' = 4.46-4.94%) was several folds higher than the 'p' distance for the taxa in the northern <span class="hlt">hemisphere</span> ('p' = 0.00-0.77%) and the southern <span class="hlt">hemisphere</span> ('p' = 0.00%). This distinct difference was also reflected by concatenated COI+COII+16S+28S+ITS-2 nucleotide sequences with an uncorrected 'p' distance of 2.34-2.69% between the taxa of northern and southern <span class="hlt">hemispheres</span>. In accordance with the type locality the Indonesian taxa belong to the nominal species. Thus the taxa from the northern <span class="hlt">hemisphere</span>, if they were to constitute a cryptic species of the B. caudata species complex based on molecular data, need to be formally described as a new species. The Thailand and Malaysian B. caudata populations in the northern <span class="hlt">hemisphere</span> showed distinct genetic structure and phylogeographic pattern. PMID:26090853</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23358602','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23358602"><span id="translatedtitle">Contralesional motor deficits after unilateral stroke reflect <span class="hlt">hemisphere</span>-specific control mechanisms.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mani, Saandeep; Mutha, Pratik K; Przybyla, Andrzej; Haaland, Kathleen Y; Good, David C; Sainburg, Robert L</p> <p>2013-04-01</p> <p>We have proposed a model of motor lateralization, in which the left and right <span class="hlt">hemispheres</span> are specialized for different aspects of motor control: the left <span class="hlt">hemisphere</span> for predicting and accounting for limb dynamics and the right <span class="hlt">hemisphere</span> for stabilizing limb position through impedance control mechanisms. Our previous studies, demonstrating different motor deficits in the ipsilesional arm of stroke patients with left or right <span class="hlt">hemisphere</span> damage, provided a critical test of our model. However, motor deficits after stroke are most prominent on the contralesional side. Post-stroke rehabilitation has also, naturally, focused on improving contralesional arm impairment and function. Understanding whether contralesional motor deficits differ depending on the <span class="hlt">hemisphere</span> of damage is, therefore, of vital importance for assessing the impact of brain damage on function and also for designing rehabilitation interventions specific to laterality of damage. We, therefore, asked whether motor deficits in the contralesional arm of unilateral stroke patients reflect <span class="hlt">hemisphere</span>-dependent control mechanisms. Because our model of lateralization predicts that contralesional deficits will differ depending on the <span class="hlt">hemisphere</span> of damage, this study also served as an essential assessment of our model. Stroke patients with mild to moderate hemiparesis in either the left or right arm because of contralateral stroke and healthy control subjects performed targeted multi-joint reaching movements in different directions. As predicted, our results indicated a double dissociation; although left <span class="hlt">hemisphere</span> damage was associated with greater errors in trajectory curvature and movement direction, errors in movement extent were greatest after right <span class="hlt">hemisphere</span> damage. Thus, our results provide the first demonstration of <span class="hlt">hemisphere</span> specific motor control deficits in the contralesional arm of stroke patients. Our results also suggest that it is critical to consider the differential deficits induced by right</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4474862','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4474862"><span id="translatedtitle">Multigene Phylogeography of Bactrocera caudata (Insecta: Tephritidae): Distinct Genetic Lineages in Northern and Southern <span class="hlt">Hemispheres</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yong, Hoi-Sen; Lim, Phaik-Eem; Tan, Ji; Song, Sze-Looi; Suana, I Wayan; Eamsobhana, Praphathip</p> <p>2015-01-01</p> <p>Bactrocera caudata is a pest of pumpkin flower. Specimens of B. caudata from the northern <span class="hlt">hemisphere</span> (mainland Asia) and southern <span class="hlt">hemisphere</span> (Indonesia) were analysed using the partial DNA sequences of the nuclear 28S rRNA and internal transcribed spacer region 2 (ITS-2) genes, and the mitochondrial cytochrome c oxidase subunit I (COI), cytochrome c oxidase subunit II (COII) and 16S rRNA genes. The COI, COII, 16S rDNA and concatenated COI+COII+16S and COI+COII+16S+28S+ITS-2 nucleotide sequences revealed that B. caudata from the northern <span class="hlt">hemisphere</span> (Peninsular Malaysia, East Malaysia, Thailand) was distinctly different from the southern <span class="hlt">hemisphere</span> (Indonesia: Java, Bali and Lombok), without common haplotype between them. Phylogenetic analysis revealed two distinct clades (northern and southern <span class="hlt">hemispheres</span>), indicating distinct genetic lineage. The uncorrected ‘p’ distance for the concatenated COI+COII+16S nucleotide sequences between the taxa from the northern and southern <span class="hlt">hemispheres</span> (‘p’ = 4.46-4.94%) was several folds higher than the ‘p’ distance for the taxa in the northern <span class="hlt">hemisphere</span> (‘p’ = 0.00-0.77%) and the southern <span class="hlt">hemisphere</span> (‘p’ = 0.00%). This distinct difference was also reflected by concatenated COI+COII+16S+28S+ITS-2 nucleotide sequences with an uncorrected 'p' distance of 2.34-2.69% between the taxa of northern and southern <span class="hlt">hemispheres</span>. In accordance with the type locality the Indonesian taxa belong to the nominal species. Thus the taxa from the northern <span class="hlt">hemisphere</span>, if they were to constitute a cryptic species of the B. caudata species complex based on molecular data, need to be formally described as a new species. The Thailand and Malaysian B. caudata populations in the northern <span class="hlt">hemisphere</span> showed distinct genetic structure and phylogeographic pattern. PMID:26090853</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=191550','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=191550"><span id="translatedtitle">POLLINATION BIOLOGY OF A <span class="hlt">DISJUNCT</span> POPULATION OF THE ENDANGERED SANDHILLS ENDEMIC PENSTEMON HAYDENII S. WATS. (SCROPHULARIACEAE) IN WYOMING, U.S.A.</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>We studied the breeding system and pollinators of the endangered <span class="hlt">plant</span> Penstemon haydenii, at several south central Wyoming U.S.A. occurrences. In agreement with earlier studies in Nebraska, we found Wyoming <span class="hlt">plants</span> to be self-incompatible and pollinator-dependent for sexual reproduction. As in Nebr...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3534693','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3534693"><span id="translatedtitle">Historical Biogeography and Diversification of Truffles in the Tuberaceae and Their Newly Identified Southern <span class="hlt">Hemisphere</span> Sister Lineage</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Bonito, Gregory; Smith, Matthew E.; Nowak, Michael; Healy, Rosanne A.; Guevara, Gonzalo; Cázares, Efren; Kinoshita, Akihiko; Nouhra, Eduardo R.; Domínguez, Laura S.; Tedersoo, Leho; Murat, Claude; Wang, Yun; Moreno, Baldomero Arroyo; Pfister, Donald H.; Nara, Kazuhide; Zambonelli, Alessandra; Trappe, James M.; Vilgalys, Rytas</p> <p>2013-01-01</p> <p>Truffles have evolved from epigeous (aboveground) ancestors in nearly every major lineage of fleshy fungi. Because accelerated rates of morphological evolution accompany the transition to the truffle form, closely related epigeous ancestors remain unknown for most truffle lineages. This is the case for the quintessential truffle genus Tuber, which includes species with socio-economic importance and esteemed culinary attributes. Ecologically, Tuber spp. form obligate mycorrhizal symbioses with diverse species of <span class="hlt">plant</span> hosts including pines, oaks, poplars, orchids, and commercially important trees such as hazelnut and pecan. Unfortunately, limited geographic sampling and inconclusive phylogenetic relationships have obscured our understanding of their origin, biogeography, and diversification. To address this problem, we present a global sampling of Tuberaceae based on DNA sequence data from four loci for phylogenetic inference and molecular dating. Our well-resolved Tuberaceae phylogeny shows high levels of regional and continental endemism. We also identify a previously unknown epigeous member of the Tuberaceae – the South American cup-fungus Nothojafnea thaxteri (E.K. Cash) Gamundí. Phylogenetic resolution was further improved through the inclusion of a previously unrecognized Southern <span class="hlt">hemisphere</span> sister group of the Tuberaceae. This morphologically diverse assemblage of species includes truffle (e.g. Gymnohydnotrya spp.) and non-truffle forms that are endemic to Australia and South America. Southern <span class="hlt">hemisphere</span> taxa appear to have diverged more recently than the Northern <span class="hlt">hemisphere</span> lineages. Our analysis of the Tuberaceae suggests that Tuber evolved from an epigeous ancestor. Molecular dating estimates Tuberaceae divergence in the late Jurassic (∼156 million years ago), with subsequent radiations in the Cretaceous and Paleogene. Intra-continental diversification, limited long-distance dispersal, and ecological adaptations help to explain patterns of truffle</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23300990','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23300990"><span id="translatedtitle">Historical biogeography and diversification of truffles in the Tuberaceae and their newly identified southern <span class="hlt">hemisphere</span> sister lineage.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bonito, Gregory; Smith, Matthew E; Nowak, Michael; Healy, Rosanne A; Guevara, Gonzalo; Cázares, Efren; Kinoshita, Akihiko; Nouhra, Eduardo R; Domínguez, Laura S; Tedersoo, Leho; Murat, Claude; Wang, Yun; Moreno, Baldomero Arroyo; Pfister, Donald H; Nara, Kazuhide; Zambonelli, Alessandra; Trappe, James M; Vilgalys, Rytas</p> <p>2013-01-01</p> <p>Truffles have evolved from epigeous (aboveground) ancestors in nearly every major lineage of fleshy fungi. Because accelerated rates of morphological evolution accompany the transition to the truffle form, closely related epigeous ancestors remain unknown for most truffle lineages. This is the case for the quintessential truffle genus Tuber, which includes species with socio-economic importance and esteemed culinary attributes. Ecologically, Tuber spp. form obligate mycorrhizal symbioses with diverse species of <span class="hlt">plant</span> hosts including pines, oaks, poplars, orchids, and commercially important trees such as hazelnut and pecan. Unfortunately, limited geographic sampling and inconclusive phylogenetic relationships have obscured our understanding of their origin, biogeography, and diversification. To address this problem, we present a global sampling of Tuberaceae based on DNA sequence data from four loci for phylogenetic inference and molecular dating. Our well-resolved Tuberaceae phylogeny shows high levels of regional and continental endemism. We also identify a previously unknown epigeous member of the Tuberaceae--the South American cup-fungus Nothojafnea thaxteri (E.K. Cash) Gamundí. Phylogenetic resolution was further improved through the inclusion of a previously unrecognized Southern <span class="hlt">hemisphere</span> sister group of the Tuberaceae. This morphologically diverse assemblage of species includes truffle (e.g. Gymnohydnotrya spp.) and non-truffle forms that are endemic to Australia and South America. Southern <span class="hlt">hemisphere</span> taxa appear to have diverged more recently than the Northern <span class="hlt">hemisphere</span> lineages. Our analysis of the Tuberaceae suggests that Tuber evolved from an epigeous ancestor. Molecular dating estimates Tuberaceae divergence in the late Jurassic (~156 million years ago), with subsequent radiations in the Cretaceous and Paleogene. Intra-continental diversification, limited long-distance dispersal, and ecological adaptations help to explain patterns of truffle</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=only+AND+10%25+AND+brain&pg=7&id=EJ925216','ERIC'); return false;" href="http://eric.ed.gov/?q=only+AND+10%25+AND+brain&pg=7&id=EJ925216"><span id="translatedtitle">Finding the Right Word: <span class="hlt">Hemispheric</span> Asymmetries in the Use of Sentence Context Information</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Wlotko, Edward W.; Federmeier, Kara D.</p> <p>2007-01-01</p> <p>The cerebral <span class="hlt">hemispheres</span> have been shown to be differentially sensitive to sentence-level information; in particular, it has been suggested that only the left <span class="hlt">hemisphere</span> (LH) makes predictions about upcoming items, whereas the right (RH) processes words in a more integrative fashion. The current study used event-related potentials to jointly…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Body+AND+temperature&pg=4&id=EJ730562','ERIC'); return false;" href="http://eric.ed.gov/?q=Body+AND+temperature&pg=4&id=EJ730562"><span id="translatedtitle">Cognition Is Cool: Can <span class="hlt">Hemispheric</span> Activation Be Assessed by Tympanic Membrane Thermometry?</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Cherbuin, Nicolas; Brinkman, Cobie</p> <p>2004-01-01</p> <p><span class="hlt">Hemispheric</span> activation during cognitive tasks using functional magnetic resonance imaging (fMRI) can be difficult to interpret, uncomfortable, and is not widely available. This study investigated whether tympanic membrane thermometry could be used as a broad measure of <span class="hlt">hemispheric</span> activation. Infrared probes measured ear temperature continuously…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=left-handed&pg=7&id=EJ239726','ERIC'); return false;" href="http://eric.ed.gov/?q=left-handed&pg=7&id=EJ239726"><span id="translatedtitle"><span class="hlt">Hemispheric</span> Specialization in Normally and Slowly Developing Children: A Tachistoscopic and Dichaptic Evaluation.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Williams, H. G.; And Others</p> <p>1980-01-01</p> <p>Both right-and left-handed normally developing 6-year-olds showed considerable evidence of bilateralization of <span class="hlt">hemispheric</span> functions for spatial and verbal information processing; the slowly developing children (ages 5-9) exhibited unusual patterns of <span class="hlt">hemispheric</span> specialization usually opposite those typically expected in children or adults.…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSA21A4045L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSA21A4045L"><span id="translatedtitle">Longitudinal and <span class="hlt">Hemispheric</span> Variations of Nighttime E-Layer Electron Density in the Auroral Zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luan, X.; Wang, W.; Dou, X.; Burns, A. G.; Yue, X.</p> <p>2014-12-01</p> <p>The longitudinal patterns of nighttime E layer electron density in the auroral zone are analyzed in both <span class="hlt">hemispheres</span> using COSMIC observation under quiet and solar minimum conditions. These l patterns are compared with the variations of particle precipitating energy flux from TIMED/GUVI under similar geophysical conditions, and also the solar radiation source of the auroral E layer are discussed. Our main conclusions are: (1) the nighttime maximum E-layer electron density presents pronounced longitudinal variations in the auroral zone, which depends on seasons and <span class="hlt">hemispheres</span>. In local winter of both <span class="hlt">hemispheres</span> and in northern equinox, maximum electron density is located in most western sectors within magnetic longitudes of 120-360°E. In local summer of both <span class="hlt">hemispheres</span> and in southern equinox, greater the electron density occurs in a wide longitudinal sector centered at 0°E. (2) <span class="hlt">Hemispheric</span> asymmetry occurs in auroral E layer electron density in all seasons, including equinox. In local winter, the maximum density of the northern <span class="hlt">hemisphere</span> is much higher than that of southern <span class="hlt">hemisphere</span>. In equinox, the longitudinal patterns of the electron density are out of phase between the two <span class="hlt">hemispheres</span>. (3) The effects of the auroral precipitation are dominant in building the E layer electron density in the auroral zone for all seasons, except in southern summer in sector of 300-90°E MLON, where strong solar radiation takes place.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=e-database&id=EJ1005168','ERIC'); return false;" href="http://eric.ed.gov/?q=e-database&id=EJ1005168"><span id="translatedtitle">An Evidence-Based Systematic Review on Communication Treatments for Individuals with Right <span class="hlt">Hemisphere</span> Brain Damage</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Blake, Margaret Lehman; Frymark, Tobi; Venedictov, Rebecca</p> <p>2013-01-01</p> <p>Purpose: The purpose of this review is to evaluate and summarize the research evidence related to the treatment of individuals with right <span class="hlt">hemisphere</span> communication disorders. Method: A comprehensive search of the literature using key words related to right <span class="hlt">hemisphere</span> brain damage and communication treatment was conducted in 27 databases (e.g.,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=concept+AND+right&pg=4&id=EJ697525','ERIC'); return false;" href="http://eric.ed.gov/?q=concept+AND+right&pg=4&id=EJ697525"><span id="translatedtitle">Semantic Processing of Living and Nonliving Concepts across the Cerebral <span class="hlt">Hemispheres</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Pilgrim, L.K.; Moss, H.E.; Tyler, L.K.</p> <p>2005-01-01</p> <p>Studies of patients with category-specific semantic deficits suggest that the right and left cerebral <span class="hlt">hemispheres</span> may be differently involved in the processing of living and nonliving domains concepts. In this study, we investigate whether there are <span class="hlt">hemisphere</span> differences in the semantic processing of these domains in healthy volunteers. Based on…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016A%26A...592A.160L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016A%26A...592A.160L&link_type=ABSTRACT"><span id="translatedtitle">Properties of sunspot cycles and <span class="hlt">hemispheric</span> wings since the 19th century</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leussu, Raisa; Usoskin, Ilya G.; Arlt, Rainer; Mursula, Kalevi</p> <p>2016-08-01</p> <p>Aims: The latitudinal evolution of sunspot emergence over the course of the solar cycle, the so-called butterfly diagram, is a fundamental property of the solar dynamo. Here we present a study of the butterfly diagram of sunspot group occurrence for cycles 7-10 and 11-23 using data from a recently digitized sunspot drawings by Samuel Heinrich Schwabe in 1825-1867, and from RGO/USAF/NOAA(SOON) compilation of sunspot groups in 1874-2015. Methods: We developed a new, robust method of <span class="hlt">hemispheric</span> wing separation based on an analysis of long gaps in sunspot group occurrence in different latitude bands. The method makes it possible to ascribe each sunspot group to a certain wing (solar cycle and <span class="hlt">hemisphere</span>), and separate the old and new cycle during their overlap. This allows for an improved study of solar cycles compared to the common way of separating the cycles. Results: We separated each <span class="hlt">hemispheric</span> wing of the butterfly diagram and analysed them with respect to the number of groups appearing in each wing, their lengths, <span class="hlt">hemispheric</span> differences, and overlaps. Conclusions: The overlaps of successive wings were found to be systematically longer in the northern <span class="hlt">hemisphere</span> for cycles 7-10, but in the southern <span class="hlt">hemisphere</span> for cycles 16-22. The occurrence of sunspot groups depicts a systematic long-term variation between the two <span class="hlt">hemispheres</span>. During Schwabe time, the <span class="hlt">hemispheric</span> asymmetry was north-dominated during cycle 9 and south-dominated during cycle 10.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2010-06-08/pdf/2010-13661.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2010-06-08/pdf/2010-13661.pdf"><span id="translatedtitle">75 FR 32418 - Western <span class="hlt">Hemisphere</span> Institute for Security Cooperation Board of Visitors; Meeting</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2010-06-08</p> <p>... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF DEFENSE Department of the Army Western <span class="hlt">Hemisphere</span> Institute for Security Cooperation Board of Visitors; Meeting... <span class="hlt">Hemisphere</span> Institute for Security Cooperation (WHINSEC). Notice of this meeting is required under the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2010-11-23/pdf/2010-29470.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2010-11-23/pdf/2010-29470.pdf"><span id="translatedtitle">75 FR 71421 - Western <span class="hlt">Hemisphere</span> Institute for Security Cooperation Board of Visitors; Meeting</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2010-11-23</p> <p>... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF DEFENSE Department of the Army Western <span class="hlt">Hemisphere</span> Institute for Security Cooperation Board of Visitors; Meeting... <span class="hlt">Hemisphere</span> Institute for Security Cooperation (WHINSEC). Notice of this meeting is required under the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2012-04-04/pdf/2012-8047.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2012-04-04/pdf/2012-8047.pdf"><span id="translatedtitle">77 FR 20369 - Western <span class="hlt">Hemisphere</span> Institute for Security Cooperation Board of Visitors; Meeting</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2012-04-04</p> <p>... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF DEFENSE Department of the Army Western <span class="hlt">Hemisphere</span> Institute for Security Cooperation Board of Visitors; Meeting... <span class="hlt">Hemisphere</span> Institute for Security Cooperation (WHINSEC). Notice of this meeting is required under the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=animal+AND+rights&pg=5&id=EJ751846','ERIC'); return false;" href="http://eric.ed.gov/?q=animal+AND+rights&pg=5&id=EJ751846"><span id="translatedtitle">Remembering 1500 Pictures: The Right <span class="hlt">Hemisphere</span> Remembers Better than the Left</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Laeng, Bruno; Overvoll, Morten; Ole Steinsvik, Oddmar</p> <p>2007-01-01</p> <p>We hypothesized that the right <span class="hlt">hemisphere</span> would be superior to the left <span class="hlt">hemisphere</span> in remembering having seen a specific picture before, given its superiority in perceptually encoding specific aspects of visual form. A large set of pictures (N=1500) of animals, human faces, artifacts, landscapes, and art paintings were shown for 2 s in central…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=information+AND+asymmetry&pg=7&id=EJ746385','ERIC'); return false;" href="http://eric.ed.gov/?q=information+AND+asymmetry&pg=7&id=EJ746385"><span id="translatedtitle">Effect of Temporal Constraints on <span class="hlt">Hemispheric</span> Asymmetries during Spatial Frequency Processing</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Peyrin, Carole; Mermillod, Martial; Chokron, Sylvie; Marendaz, Christian</p> <p>2006-01-01</p> <p>Studies on functional <span class="hlt">hemispheric</span> asymmetries have suggested that the right vs. left <span class="hlt">hemisphere</span> should be predominantly involved in low vs. high spatial frequency (SF) analysis, respectively. By manipulating exposure duration of filtered natural scene images, we examined whether the temporal characteristics of SF analysis (i.e., the temporal…</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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