991 resultados para 1010


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Texas is home to over one million Latino teens who are at risk for negative reproductive health outcomes, such as teen pregnancy and STIs. Teen pregnancy disproportionately impacts the health of Latino teens in Texas and places them at risk of continued high rates of poverty, school dropout, and unemployment unless Texas makes a concerted effort to reduce its teen pregnancy rate. The birth rate among Latina girls is astonishing: 98 per 1000 Latinas (aged 15-19) are giving birth. This translates to over 32,000 births each year among Latina teens, costing almost $98 million in direct medical expenditures and well over $638 million if other costs are included. Most teens become sexually experienced while they are of school age, which translates to an estimated 414,583 sexually experienced Latino students attending Texas public schools. Of these Latino youth, 237,466 report being currently sexually active, and 89,000 report having had four or more sexual partners in their lifetime. While causes of teen pregnancy are complex, the solutions to teen pregnancy are known. Texas needs an effective, comprehensive approach to address the sexual health needs of Texas Latino youth that includes: statewide implementation and monitoring of evidence-based sex education for middle school and high school students, access to reproductive health services for students who are already sexually experienced, and widespread training on adolescent sexual health for teachers, service providers, and parents. By tackling teen pregnancy, we can positively impact the future and well-being of not only Latinos, but of all Texans, and subsequently can contribute to the social and economic success of Texas.

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Studies of intraspecific morphological variation in fishes have traditionally focused on freshwater rather than marine species. In addition, such studies typically focus on adults, although causes and intensities of selective pressures most likely vary through an individual’s lifetime. In this study, body and head shape of a marine species, shiner perch Cymatogaster aggregata Gibbons were compared among localities along the Pacific Northwest coast of North America. Evidence was found for intraspecific variation in ontogenetic allometry, and for a closer correlation of body shape with environment rather than geographical proximity. This correlation with environment was more evident in younger fish, thereby demonstrating the importance of analysing multiple life stages. A common garden experiment suggests both environmental and genetic bases for the observed differences. Recognizing intraspecific ecomorphological complexity and its specificity to habitat and/or life stage can have important consequences for understanding the role of local adaptation and population dynamics in macroecology.

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Im Rahmen einer Längsschnittstudie wurde untersucht, wie sich die schulische Lernfreude bei österreichischen Hauptschülern und Hauptschülerinnen zwischen der 6. und 7. Schulstufe (N = 356) entwickelt. Des Weiteren wurde die Rolle von Kontroll- und Valenzkognitionen, die gemäß der Kontroll-Wert-Theorie (Pekrun, 2000, 2006) für das Entstehen der schulischen Lernfreude zentral sein sollten, geprüft. Als Methoden zur Erfassung der habituellen und aktuellen Merkmale kamen Fragebögen und Tagebücher zum Einsatz. Die Ergebnisse belegen den Rückgang der Lernfreude während dieses von Fend (1997) als «kritisch» bezeichneten Schuljahres. Ebenso erweisen sich hohe Kontrollkognitionen und positive Valenzkognitionen als bedeutsam für die schulische Lernfreude, sie schützen jedoch nicht vor ihrem Rückgang. Der Zusammenhang von Lernfreude und Kognitionen bedarf daher weiterer Klärung.

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The fall 1007 issue of The Olive Tree features articles about library projects, collections, technological innovations, and events at Fogler Library, University of Maine.

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The Flavell (l981) model of cognitive monitoring and metamnemonic development was tested by four experiments conducted to determine whether preschool children (1) recognize that mood, fatigue, and fear are variables that influence learning; and (2) self-monitor their internal states and adjust their study behavior when they are sad or tired.

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We present a reconstruction of Antarctic mean surface temperatures over the past two centuries based on water stable isotope records from high-resolution, precisely dated ice cores. Both instrumental and reconstructed temperatures indicate large interannual to decadal scale variability, with the dominant pattern being anti-phase anomalies between the main Antarctic continent and the Antarctic Peninsula region. Comparative analysis of the instrumental Southern Hemisphere (SH) mean temperature record and the reconstruction suggests that at longer timescales, temperatures over the Antarctic continent vary in phase with the SH mean. Our reconstruction suggests that Antarctic temperatures have increased by about 0.2 degrees C since the late nineteenth century. The variability and the long-term trends are strongly modulated by the SH Annular Mode in the atmospheric circulation.

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Die Studie untersucht, wie 70 Kindergartenkinder im Vergleich zu 71 Fünft- und Sechstklässler über Situationen denken, in welchen sich ein Protagonist für die Wahl eines behinderten oder nicht behinderten Kindes in seine Gruppe entscheiden musste. Die Situationen wurden nach Behinderungsform des behinderten Kindes (geistig behindert, körperbehindert) und nach Gruppenaktivität (schulisch, sozial, sportlich) variiert. Die Kinder sollten die Wahl des Protagonisten vorhersagen und die Wahl begründen. Die älteren Kinder berücksichtigten in ihren Überlegungen stärker den situativen Kontext als die jüngeren Kinder. Allerdings erwarteten sie weniger häufig den Einschluss des geistig behinderten Kindes als den Einschluss des körperbehinderten Kindes. Die Ergebnisse der Studie werden vor dem Hintergrund von Forschung zur Entwicklung sozialen und moralischen Denkens über Ein- und Ausschluss diskutiert.

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K-feldspar (Kfs) from the Chain of Ponds Pluton (CPP) is the archetypal reference material, on which thermochronological modeling of Ar diffusion in discrete “domains” was founded. We re-examine the CPP Kfs using cathodoluminescence and back-scattered electron imaging, transmission electron microscopy, and electron probe microanalysis. 40Ar/39Ar stepwise heating experiments on different sieve fractions, and on handpicked and unpicked aliquots, are compared. Our results reproduce the staircase-shaped age spectrum and the Arrhenius trajectory of the literature sample, confirming that samples collected from the same locality have an identical Ar isotope record. Even the most pristine-looking Kfs from the CPP contains successive generations of secondary, metasomatic/retrograde mineral replacements that post-date magmatic crystallization. These chemically and chronologically distinct phases are responsible for its staircase-shaped age spectra, which are modified by handpicking. While genuine within-grain diffusion gradients are not ruled out by these data, this study demonstrates that the most important control on staircase-shaped age spectra is the simultaneous presence of heterochemical, diachronous post-magmatic mineral growth. At least five distinct mineral species were identified in the Kfs separate, three of which can be traced to external fluids interacting with the CPP in a chemically open system. Sieve fractions have size-shifted Arrhenius trajectories, negating the existence of the smallest “diffusion domains”. Heterochemical phases also play an important role in producing non-linear trajectories. In vacuo degassing rates recovered from Arrhenius plots are neither related to true Fick’s Law diffusion nor to the staircase shape of the age spectra. The CPP Kfs used to define the "diffusion domain" model demonstrates the predominance of metasomatic alteration by hydrothermal fluids and recrystallization in establishing the natural Ar distribution amongst different coexisting phases that gives rise to the staircase-shaped age spectrum. Microbeam imaging of textures is as essential for 40Ar-39Ar hygrochronology as it is for U-Pb geochronology.

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The deceptive Iris lutescens (Iridaceae) shows a heritable and striking flower colour polymorphism, with both yellow- and purple-flowered individuals growing sympatrically. Deceptive species with flower colour polymorphism are mainly described in the family Orchidaceae and rarely found in other families. To explain the maintenance of flower colour polymorphism in I.lutescens, we investigated female reproductive success in natural populations of southern France, at both population and local scales (within populations). Female reproductive success was positively correlated with yellow morph frequency, at both the population scale and the local scale. Therefore, we failed to observe negative frequency-dependent selection (NFDS), a mechanism commonly invoked to explain flower colour polymorphism in deceptive plant species. Flower size and local flower density could also affect female reproductive success in natural populations. Pollinator behaviour could explain the positive effect of the yellow morph, and our results suggest that flower colour polymorphism might not persist in I.lutescens, but alternative explanations not linked to pollinator behaviour are discussed. In particular, NFDS, although an appealingly simple explanation previously demonstrated in orchids, may not always contribute to maintaining flower colour polymorphism, even in deceptive species.