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Key Hypothesis (key + hypothesis)

Distribution by Scientific Domains

Medical Sciences	60%

Selected Abstracts

The Versatility of Helicobacter pylori CagA Effector Protein Functions: the Master Key Hypothesis

HELICOBACTER, Issue 5 2010
Steffen Backert
No abstract is available for this article. [source]

,Motor Magic': Evaluation of a community capacity-building approach to supporting the development of preschool children

AUSTRALIAN OCCUPATIONAL THERAPY JOURNAL, Issue 3 2006
Naomi Priest
Background and Aims:,There is a lack of literature on the evaluation of programmes addressing the motor and sensory development of preschool children. This paper presents and discusses an exploratory evaluation study of the ,Motor Magic' programme run in Adelaide, South Australia. The purpose of this study was to identify outcomes for children, parents and kindergarten staff, as well as develop hypotheses about how these outcomes occurred and in what contexts. Methods:,Using a realist approach, two focus groups were conducted, one with parents and one with kindergarten staff, to develop and refine key hypotheses. Results and Conclusion:,Evaluation results for participating children and parents suggested that this programme provided a model of best practice for supporting the development of preschool-aged children, with or at risk of, developmental delay, within their family and social environments. [source]

Do the Transtheoretical Model processes of change, decisional balance and temptation predict stage movement?

ADDICTION, Issue 5 2009
Evidence from smoking cessation in adolescents
ABSTRACT Aims To examine the effects of processes of change (POC) on forward stage movement directly, indirectly through decisional balance and temptation, and total effects as a test of the key hypothesis of the Transtheoretical Model (TTM). Design Prospective cohort study. Setting United Kingdom. Participants A total of 1160 adolescents aged 13,14 years who were current or former smokers at baseline. Measurements Stage was assessed with the standard algorithm three times, once every 3 months. On each occasion the POC, decisional balance and temptation were measured with the standard questionnaires. Path analysis was used to examine the direct, indirectly mediated and total contribution of POC and the other constructs to stage movement 3 months later. Findings Four of the 24 analyses showed evidence that the theoretically appropriate POC predicted stage transition, with statistically significant total effects. Effect sizes were small. When the POC were summarized to experiential and behavioural process means, one transition from pre-contemplation was predicted by experiential processes and, contrary to the TTM, one transition predicted by behavioural processes. There was slightly more evidence that decisional balance (attitudes towards smoking) and temptation (ability to resist the urge to smoke) was associated with stage transition. Conclusions POC use was not associated generally with stage transition and evidence that effects, if missed, must be modest, giving no support to the central tenet of the TTM. [source]

Taxonomic revision of Mecyclothorax Sharp (Coleoptera, Carabidae) of Hawaii Island: abundant genitalic variation in a nascent island radiation

MITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE IN BERLIN-DEUTSCHE ENTOMOLOGISCHE ZEITSCHRIFT, Issue 1 2008
James K. Liebherr
Abstract The Hawaii Island fauna of Mecyclothorax Sharp, 1903 is taxonomically revised and found to comprise 30 species, 18 newly described: M. gagnei sp. n., M. nitidus sp. n., M. maunakukini sp. n., M. punakukini sp. n., M. kaukukini sp. n., M. perivariipes sp. n., M. aa sp. n., M. giffini sp. n., M. hephaestus sp. n., M. funebris sp. n., M. granulipennis sp. n., M. rufipennis sp. n., M. blackburnianus sp. n., M. swezeyi sp. n., M. sinuosus sp. n., M. williamsi sp. n., M. purpuripennis sp. n., and M. footei sp. n. New synonymies include: Mecyclothorax parvus Britton, 1948 = M. subunctus (Perkins), 1917; Thriscothorax munroi Perkins, 1937 = M. karschi (Blackburn), 1882; Thriscothorax gracilis Sharp, 1903 and Mecyclothorax proximus Britton, 1948 = M. konanus Sharp, 1903; Mecyclothorax terminalis Britton, 1948 = M. discedens (Sharp) 1903. Mecyclothorax vulcanus (Blackburn) was described from a mixed series, with the cryptic sibling species M. hephaestus newly described to correct the partial misidentification. Species delimitation for the highly variable M. konanus is achieved using a hierarchical analysis based on infraspecifically variable attributes. Extensive male genitalic variation is documented within M. konanus and M. deverilli (Blackburn), and also among the cryptic sibling species pair M. variipes (Blackburn) and M. perivariipes. The observed variation is consistent with various hypotheses of sexual selection, but not with the genitalic lock and key hypothesis. Areas of endemism are tentatively proposed based on the most restricted distributions of Hawaii Island Mecyclothorax, with various flanks of Mauna Kea and Mauna Loa volcanoes identified as distinctive areas. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

POPs , schwer abbaubare Chemikalien

CHEMIE IN UNSERER ZEIT (CHIUZ), Issue 3 2007
Gerhard Lammel Professor
Abstract POPs, persistent organic pollutants, sind in der Umwelt schwer abbaubare, gleichzeitig bioakkumulative und toxische Stoffe. Die meisten sind mittelflüchtig und lipophil. Sie werden in der Atmosphäre zu einem erheblichen Teil an Aerosolpartikel sorbiert und nach Ablagerung am Boden oder Deposition in den Ozean in die Atmosphäre zurück verflüchtigt und können so mehrere Emissions-Transport-Depositions-Zyklen durchlaufen. Die Transport- und Verteilungsmuster und das Ferntransport-Potenzial sind damit ganz anders als bei herkömmlichen Luftschadstoffen, deren Transport nach Ablagerung aus der Atmosphäre endet. Dass weite Strecken durch mehrere, jeweils kürzere Wege überwunden werden können, wird als Grashüpfer-Effekt bezeichnet. Eine wichtige Hypothese der Umweltchemie besagt, dass die beobachtete Anreicherung von vielen persistenten und bioakkumulativen Schadstoffen in den Polargebieten, fernab der Anwendungsgebiete eine Konsequenz des Grashüpfer-Effekts sei in Verbindung mit stärkerer Kondensation in kalten Gebieten. Die Lipophilie ist die Voraussetzung für die Bioakkumulation und beeinflusst die Verteilung der Stoffe über mehrere Umweltmedien. Weil es sich bei den POPs im Allgemeinen um teilhalogenierte Stoffe handelt, ist der atmosphärische Abbau zumeist langsamer als für andere Luftschadstoffe, aber schneller als in den anderen Umweltkompartimenten, in denen erst bei Verweildauern von Monaten von Persistenz gesprochen wird. Ferntransport-Potenzial und Persistenz eines Stoffes sind wichtig für die Einschätzung der Gefährdung, die von ihm ausgeht. Sie sind das Ergebnis des Zusammenwirkens physikalisch-chemischer Stoffeigenschaften mit den in Raum und Zeit variablen Umweltbedingungen. Sie variieren deswegen in Raum und Zeit. POPs, persistent organic pollutants, are slowly degradable, bio-accumulative and toxic substances. Most of them are semivolatile and lipophilic. In the atmosphere they sorb to aerosol particles, and upon deposition to soil or water surfaces they may return through volatilisation, enabling them to undergo sequential cycles of emission, atmospheric transport and deposition. These patterns of transport and distribution as well as the long-range transport potential differ significantly from those of conventional air pollutants, which undergo only one such cycle. The capability to travel long distances by several hops is called the grasshopper effect. According to a key hypothesis of environmental chemistry the accumulation of persistent and bio-accumulative pollutants in polar regions, far from the areas of usage, is due to the combination of the grasshopper effect and enhanced condensation in cold areas. Lipophilicity is a prerequisite for bio-accumulation and influences the partitioning among environmental media (multicompartment compounds). As POPs are typically halogenated compounds, chemical degradation in the atmosphere is in most cases slower than of other air pollutants, but faster than in the other environmental compartments, where persistence coincides with residence times of months. The long-range transport potential and persistence are crucial for chemical hazard assessment. These characteristics result from the combined action of physico-chemical properties and environmental conditions variable in time and space. Hence, they vary in time and space. [source]