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The development of phonetic codes in memory of 141 pairs of normal and disabled readers from 7.8 to 16.8 years of age was tested with a task adapted from L. S. Mark, D. Shankweiler, I. Y. Liberman, and C. A. Fowler (Memory & Cognition, 1977, 5, 623–629) that measured false-positive errors in recognition memory for foil words which rhymed with words in the memory list versus foil words that did not rhyme. Our younger subjects replicated Mark et al., showing a larger difference between rhyming and nonrhyming false-positive errors for the normal readers. The older disabled readers' phonetic effect was comparable to that of the younger normal readers, suggesting a developmental lag in their use of phonetic coding in memory. Surprisingly, the normal readers' phonetic effect declined with age in the recognition task, but they maintained a significant advantage across age in the auditory WISC-R digit span recall test, and a test of phonological nonword decoding. The normals' decline with age in rhyming confusion may be due to an increase in the precision of their phonetic codes.
Linguistic and psycholinguistic accounts based on the study of English may prove unreliable as guides to sentence processing in even closely related languages. The present study illustrates this claim in a test of sentence interpretation by German-, Italian-, and English-speaking adults. Subjects were presented with simple transitive sentences in which contrasts of (1) word order, (2) agreement, (3) animacy, and (4) stress were systematically varied. For each sentence, subjects were asked to state which of the two nouns was the actor. The results indicated that Americans relied overwhelming on word order, using a first-noun strategy in NVN and a second-noun strategy in VNN and NNV sentences. Germans relied on both agreement and animacy. Italians showed extreme reliance on agreement cues. In both German and Italian, stress played a role in terms of complex interactions with word order and agreement. The findings were interpreted in terms of the “competition model” of Bates and MacWhinney (in H. Winitz (Ed.), Annals of the New York Academy of Sciences Conference on Native and Foreign Language Acquisition. New York: New York Academy of Sciences, 1982) in which cue validity is considered to be the primary determinant of cue strength. According to this model, cues are said to be high in validity when they are also high in applicability and reliability.
The optical density of human macular pigment was measured for 50 observers ranging in age from 10 to 90 years. The psychophysical method required adjusting the radiance of a 1°, monochromatic light (400–550 nm) to minimize flicker (15 Hz) when presented in counterphase with a 460 nm standard. This test stimulus was presented superimposed on a broad-band, short-wave background. Macular pigment density was determined by comparing sensitivity under these conditions for the fovea, where macular pigment is maximal, and 5° temporally. This difference spectrum, measured for 12 observers, matched Wyszecki and Stiles's standard density spectrum for macular pigment. To study variation in macular pigment density for a larger group of observers, measurements were made at only selected spectral points (460, 500 and 550 nm). The mean optical density at 460 nm for the complete sample of 50 subjects was 0.39. Substantial individual differences in density were found (ca. 0.10–0.80), but this variation was not systematically related to age.
In order to investigate the temporal characteristics of cognitive processing, we apply multivariate phase synchronization analysis to event-related potentials. The experimental design combines a semantic incongruity in a sentence context with a physical mismatch (color change). In the ERP average, these result in an N400 component and a P300-like positivity, respectively. The synchronization analysis shows an effect of global desynchronization in the theta band around 288ms after stimulus presentation for the semantic incongruity, while the physical mismatch elicits an increase of global synchronization in the alpha band around 204ms. Both of these effects clearly precede those in the ERP average. Moreover, the delay between synchronization effect and ERP component correlates with the complexity of the cognitive processes.
Fast analysis of different species of molecules in soils is investigated by capillary electrophoresis (CE). Several CE techniques for the analysis of inorganic ions and carbohydrates have been tested. With regard to the intents of pedologists and the usually large number of soil analyses a bundle of CE systems is proposed, capable of effecting time-saving soil analyses. Adapted electrolyte systems recently published and new separation systems are described. Examples of the application of these methods to two different soil samples are presented.
The haemolymph of the adult Colorado potato beetle, Lepinotarsa decemlineata Say, contains a high molecular weight (MW > 200,000) JH-III specific binding protein. The Kd value of the protein for racemic JH-III is 1.3 ± 0.2 × 10−7 M. It has a lower affinity for racemic JH-I and it does not bind JH-III-diol or JH-III-acid. The binding protein does discriminate between the enantiomers of synthetic, racemic JH-III as was determined by stereochemical anaysis of the bound and the free JH-III. Incubation of racemic JH-III with crude haemolymph results in preferential formation of (10S)-JH-III-acid, the unnatural configuration. The JH-esterase present in L. decemlineata haemolymph is not enantioselective. It is concluded that the most important function of the binding protein is that of a specific carrier, protecting the natural hormone against degradation by esterases. The carrier does not protect JH-I as efficiently as the lower homologue.
The site of confluence of the artery and the portal vein in the liver still appears to be controversial. Anatomical studies suggested a presinusoidal or an intrasinusoidal confluence in the first, second or even final third of the sinusoids. The objective of this investigation was to study the problem with functional biochemical techniques. Rat livers were perfused through the hepatic artery and simultaneously either in the orthograde direction from the portal vein to the hepatic vein or in the retrograde direction from the hepatic vein to the portal vein. Arterial how was linearly dependent on arterial pressure between 70 cm H2O and 120 cm H2O at a constant portal or hepatovenous pressure of 18 cm H2O. An arterial pressure of 100 cm H2O was required for the maintenance of a homogeneous orthograde perfusion of the whole parenchyma and of a physiologic ratio of arterial to portal how of about 1:3. Glucagon was infused either through the artery or the portal vein and hepatic vein, respectively, to a submaximally effective ''calculated'' sinusoidal concentration after mixing of 0.1 nmol/L. During orthograde perfusions, arterial and portal glucagon caused the same increases in glucose output. Yet during retrograde perfusions, hepatovenous glucagon elicited metabolic alterations equal to those in orthograde perfusions, whereas arterial glucagon effected changes strongly reduced to between 10% and 50%. Arterially infused trypan blue was distributed homogeneously in the parenchyma during orthograde perfusions, whereas it reached clearly smaller areas of parenchyma during retrograde perfusions. Finally, arterially applied acridine orange was taken up by all periportal hepatocytes in the proximal half of the acinus during orthograde perfusions but only by a much smaller portion of periportal cells in the proximal third of the acinus during retrograde perfusions. These findings suggest that in rat liver, the hepatic artery and the portal vein mix before and within the first third of the sinusoids, rather than in the middle or even last third.
Auszug: Aphasien sind variable Sprachstörungen, die auf umschriebene Hirnläsionen zurückführbar sind und die Produktion und Verständnis separat oder kombiniert betreffen (Weniger 2003). Hierbei wird das klinische Syndrom oft mit der Lokalisation der morphologischen Gehirndefekte (z. B. durch Hirn-infarkte oder -blutungen oder Tumoren) korreliert. Sprachkompetenz gilt in erster Linie als eine Leistung des Kortex, jedoch wurden v. a. im Zuge sich verbessernder bildgebender Verfahren aphasische Syndrome auch nach Läsionen subkortikaler Hirnregionen, insbesondere der Basalganglien und des Thalamus nachgewiesen (Wallesch & Papagno 1988; Friston et al. 1993; Nadeau & Crosson 1997; Zoppelt & Daum 2003; DeWitte et al. 2006; Wahl in Druck). Diese Strukturen liegen in der Tiefe des Gehirns und kommunizieren über weit gefächerte Faserverbindungen mit dem Kortex. In erster Linie werden den Basalganglien senso-motorische Kontrollfunktionen zugewiesen (Alexander et al. 1986). Diverse Erkrankungen, die durch Störungen physiologischer Bewegungsabläufe gekennzeichnet sind (z. B. Morbus Parkinson, Chorea Huntington), werden auf Funktionsdefekte dieser Strukturen zurückgeführt. Hierbei wurde der Thalamus häufig als Relais-Station des Informationsaustauschs zwischen anatomisch entfernten Arealen des Nervensystems aufgefasst. Basalganglien und Thalamus jedoch können darüber hinausgehende Funktionen, z. B. zur Bereitstellung, Aufrechterhaltung und Auslenkung von Aufmerksamkeit bei der Bearbeitung kognitiver Aufgaben, zugesprochen werden (Cavedini et al. 2006; Piguet et al. 2006; Klostermann et al. 2006; Marzinzik et al. 2008). [...]
Auszug: Wie arbeitet unser Gehirn? Was sind die Grundlagen der Kognition? Wie funktioniert unser Sprachsystem? Das ist nur ein kleiner Teil der Probleme, mit denen sich Kognitionsforscher und Neurowissenschaftler auf der ganzen Welt auseinandersetzen. Die Frage nach den neurofunktionellen Grundlagen der Sprachverarbeitung hat dabei zunehmend an Bedeutung gewonnen. Obwohl jedes gesunde Kind problemlos und auch unter schwierigen Bedingungen Sprache erwerben und verwenden kann, sind die zugrunde liegenden kognitiven und neurofunktionellen Mechanismen hierfür noch weitgehend ungeklärt. Immer häufiger werden neurolinguistische Fragestellungen mit funktionell-bildgebenden und anderen modernen Verfahren der Hirnforschung untersucht. Ein wesentliches Ziel dieser Forschungsbemühungen ist es, herauszufinden, wie Bedeutungen und Wörter in unserem Gehirn gespeichert sind. Ein besonderes Interesse wird gegenwärtig dem Problem der neuronalen Verarbeitung von Nomen und Verben entgegengebracht. Aktuelle Fragestellungen sind dabei, welche neuroanatomischen Korrelate der Verarbeitung von Nomen und Verben unterliegen und ob es Faktoren gibt, die die Verarbeitung beeinflussen. Zur Beantwortung dieser und weiterer Fragestellungen wurden im Rahmen meines Forschungsprojektes1 funktionelle Magnetresonanzdaten zum Benennen von Nomen und Verben bereitgestellt. Die wichtigsten Methoden und Ergebnisse sollen im Folgenden kurz dargelegt werden. [...]
Auszug: Bei der Beschreibung und Analyse von zentralen Störungen des Nachsprechens stehen - wie bei der Beschreibung und Analyse von Sprachproduktionsstörungen allgemein - Abweichungen auf der lautlichen Ebene zumeist im Vordergrund. In der schwersten Form solcher Störungen können dabei nur noch phonematische Neologismen produziert werden. Doch auch die Definition phonematischer Neologismen als „Wörter, die in der Standardsprache aus lautlichen Gründen … nicht vorkommen“ (Huber et al. 1983) bzw. „Lautkette, … die als solche kein Wort der betreffenden Sprache ist“ (Tesak 2006) beschränkt sich auf segmentale Abweichungen. Prosodische Abweichungen hingegen - insbesondere Abweichungen bei der Wortbetonung - sowie mögliche Wechselwirkungen zwischen segmentalen und prosodischen Eigenschaften von Stimulus und Reaktion werden kaum diskutiert. [...]
Auszug: Etwa zwei Drittel aller Ausgaben der Krankenkassen für das Heilmittel Sprachtherapie betreffen ein Klientel in der Altersgruppe der 0- bis 15-jährigen (GVK-HIS Bundesrepublik 2007). Spracherwerbsstörungen stellen das häufigste Entwicklungsrisiko bei Kindern dar. Ca. 18% der einzuschulenden Kinder weisen einen Förderbedarf im Entwicklungsbereich Sprache auf (Tollkühn 2001) und ca. 18% der 6-jährigen Jungen erhalten nach dem Heilmittelbericht 2006 Sprachtherapieverordnungen (Schröder & Waltersbacher 2006). Die überwiegende Mehrheit erhält diese Verordnung aufgrund der Zuweisung des Indikationsschlüssels „Störungen der Sprache vor Abschluss der Sprachentwicklung“. Darunter fallen v.a. Kinder mit einer primären Spracherwerbsstörung, für deren Art und Ausmaß keine Hörstörung, keine Intelligenzbeeinträchtigung, keine neurologische Schädigung oder soziale Deprivation verantwortlich gemacht werden kann. Für diese besondere Entwicklungssituation wird die Diagnose „Spezifische Spracherwerbsstörung (SSES)“ vergeben (Grimm 2003; Dannenbauer 2002). [...]
Auszug: Seit langem ist bekannt, dass Kinder mit Sprachentwicklungsstörungen meist schon in einem frühen Stadium ihrer Sprachentwicklung auffallen: die ersten Wörter werden verspätet produziert, der Wortschatz wächst langsamer an, der Vokabularspurt setzt verzögert ein oder bleibt aus, so dass das produktive Vokabular mit zwei Jahren weniger als 50 Wörter umfasst. Außerdem treten keine Wortkombinationen auf. Obwohl bei nahezu jeder Sprachentwicklungs-störung retrospektiv derartige frühe Anzeichen auszumachen sind, mündet andererseits nicht jede frühe Verzögerung in eine anhaltende Störung. Diese Beobachtung hat Anlass zu einer regen Forschungstätigkeit gegeben. Im Zentrum steht die Frage, anhand welcher Kriterien sich der weitere Entwicklungsverlauf eines sprachlich verzögerten Kindes prognostizieren lässt. Der Forschungsstand zu diesem Bereich wurde an anderer Stelle bereits ausführlich beschrieben (z. B. in Kauschke 2000, 2003, 2006a). In diesem Beitrag möchte ich die Entwicklungswege dieser Population anhand aktueller Studien skizzieren, die Problematik der Prädiktion ansprechen und eine Studie über Sprachentwicklungsverläufe im dritten Lebensjahr vorstellen, in der ungestörte Kinder und sprachlich verzögerte längsschnittlich beobachtet wurden. Es folgen Überlegungen zur Therapienotwendigkeit und Therapiekonzeption, die durch die Darstellung eines exemplarischen Therapieverlaufs bei einem Einzelfall illustriert werden. [...]
Auszug: Lange Zeit hat die Spracherwerbsforschung den Erwerb des syntaktischen Wissens in den Mittelpunkt gestellt, da Syntax als humanspezifisch angesehen und somit als der zentrale Bereich von Sprache verstanden wurde. Auch ein aktueller Aufsatz von Hauser, Chomsky & Fitch (2002) setzt die Sprachfähigkeit im engeren Sinne („language faculty narrow“) mit dem in der Syntax gegebenen Rekursionsmechanismus gleich. Syntax, so die Autoren weiter, konnte bislang noch keinem subhumanen Primaten beigebracht werden, wohingegen ein Erwerb von Wörtern bereits belegt wurde. So lernte beispielsweise der Bonobo Kanzi knapp 600 Begriffe (Savage-Rumbaughh & Lewin 1994). Lässt sich daraus ableiten, dass Wörter im Rahmen der menschlichen Sprachfähigkeit weniger wichtig sind als das syntaktische Wissen? Sind Wörter letztendlich nur „Zierrat“ an einem rein syntaktischen Sprachgebäude? [...]
Small livestock is an important resource for rural human populations in dry climates. How strongly will climate change affect the capacity of the rangeland? We used hierarchical modelling to scale quantitatively the growth of shrubs and annual plants, the main food of sheep and goats, to the landscape extent in the eastern Mediterranean region. Without grazing, productivity increased in a sigmoid way with mean annual precipitation. Grazing reduced productivity more strongly the drier the landscape. At a point just under the stocking capacity of the vegetation, productivity declined precipitously with more intense grazing due to a lack of seed production of annuals. We repeated simulations with precipitation patterns projected by two contrasting IPCC scenarios. Compared to results based on historic patterns, productivity and stocking capacity did not differ in most cases. Thus, grazing intensity remains the stronger impact on landscape productivity in this dry region even in the future.
A multitype Dawson-Watanabe process is conditioned, in subcritical and critical cases, on non-extinction in the remote future. On every finite time interval, its distribution is absolutely continuous with respect to the law of the unconditioned process. A martingale problem characterization is also given. Several results on the long time behavior of the conditioned mass process - the conditioned multitype Feller branching diffusion - are then proved. The general case is first considered, where the mutation matrix which models the interaction between the types, is irreducible. Several two-type models with decomposable mutation matrices are analyzed too .
Team diversity
(2007)
Team diversity refers to the differences between team members on any attribute that may lead each single member of the group to perceive any other member of the group as being different from the self of this particular member. These attributes and perceptions refer to all dimensions people can differ on, such as age, gender, ethnicity, religious and functional background, personality, skills, abilities, beliefs, and attitudes.
The authors used the frameworks of reciprocal determinism and occupational socialization to study the effects of work characteristics (consisting of control and complexity of work) on personal initiative (PI)--mediated by control orientation (a 2nd-order factor consisting of control aspiration, perceived opportunity for control, and self-efficacy) and the reciprocal effects of PI on changes in work characteristics. They applied structural equation modeling to a longitudinal study with 4 measurement waves (N = 268) in a transitional economy: East Germany. Results confirm the model plus 1 additional, nonhypothesized effect. Work characteristics had a synchronous effect on PI via control orientation (full mediation). There were also effects of control orientation and of PI on later changes in work characteristics: As predicted, PI functioned as partial mediator, changing work characteristics in the long term (reciprocal effect); unexpectedly, there was a 2nd reciprocal effect of an additional lagged partial mediation of control orientation on later work characteristics.
Observational evidence exists that winds of massive stars are clumped. Many massive star systems are known as non-thermal particle production sites, as indicated by their synchrotron emission in the radio band. As a consequence they are also considered as candidate sites for non-thermal high-energy photon production up to gamma-ray energies. The present work considers the effects of wind clumpiness expected on the emitting relativistic particle spectrum in colliding wind systems, built up from the pool of thermal wind particles through diffusive particle acceleration, and taking into account inverse Compton and synchrotron losses. In comparison to a homogeneous wind, a clumpy wind causes flux variations of the emitting particle spectrum when the clump enters the wind collision region. It is found that the spectral features associated with this variability moves temporally from low to high energy bands with the time shift between any two spectral bands being dependent on clump size, filling factor, and the energy-dependence of particle energy gains and losses.
The most massive stars are those with the shortest but most active life. One group of massive stars, the Luminous Blue Variables (LBVs), of which only a few objects are known, are in particular of interest concerning the stability of stars. They have a high mass loss rate and are close to being instable. This is even more likely as rotation becomes an important factor in stellar evolution of these stars. Through massive stellar winds and sometimes giant eruptions, LBV nebulae are formed. Various aspects in the evolution in the LBV phase lead, beside the large scale morphological and kinematical differences, to a diversity of small structures like clumps, rims, and outflows in these nebulae.
Gamma-rays can be produced by the interaction of a relativistic jet and the matter of the stellar wind in the subclass of massive X-ray binaries known as “microquasars”. The relativistic jet is ejected from the surroundings of the compact object and interacts with cold protons from the stellar wind, producing pions that then quickly decay into gamma-rays. Since the resulting gamma-ray emissivity depends on the target density, the detection of rapid variability in microquasars with GLAST and the new generation of Cherenkov imaging arrays could be used to probe the clumped structure of the stellar wind. In particular, we show here that the relative fluctuation in gamma rays may scale with the square root of the ratio of porosity length to binary separation, $\sqrt{h/a}$, implying for example a ca. 10% variation in gamma ray emission for a quite moderate porosity, h/a ∼ 0.01.