133 research outputs found
Holistic wild bee management in urban spaces
Projects promoting bees in urban areas are initiated in cities around the world but evidence-based conservation concepts at a city-wide scale are scarce. We developed a holistic approach for assessment of bee and flowering plant diversity in a medium-sized city. In addition to standard mapping approaches in bee hotspots, we initiated citizen science projects for participative urban bee research to be able to collect comprehensive bee data across the entire city. We identified 22 hotspots of bee diversity, analyzed connectivity between those hotspots and evaluated the impact of flower patches planted in collaboration with the municipal gardens department as stepping stones for oligolectic bee species throughout the city. Participation by urban citizens in bee identification trainings was high (c. 630 persons) but their subsequent contribution through observation reports was relatively low (1,165 records by 140 observers). However, we identified a total of 139 bee taxa, seven of them only discovered by citizen scientists. Total species richness was higher in extensively managed orchards than in semi-natural and wasteland areas. Half of the stepping stone flower patches were occupied by the target oligolectic bee species in the year of planting. After 3 years, all but two species could be confirmed. We suggest a 5-step concept for bee management in cities: (1) identification of bee hotspots combined with standardized surveys, especially of rare species; (2) training of citizen scientists at two different levels for comprehensive surveys in all parts of the city: (a) half-day introductions to wild bee diversity, ecology and conservation in order to create more awareness and (b) 2-weeks workshops for in-depth training of a small number of dedicated citizen scientists; (3) extensive management of existing habitats and special conservation programs for very rare species; (4) creation of high-value habitats which take into account the varied resource needs of bees within flight ranges of only a few hundred meters; (5) creation of stepping stone habitats as floral and nesting resources, integrating educative and participative aspects
Parameterized optimized effective potential for atoms
The optimized effective potential equations for atoms have been solved by
parameterizing the potential. The expansion is tailored to fulfill the known
asymptotic behavior of the effective potential at both short and long
distances. Both single configuration and multi configuration trial wave
functions are implemented. Applications to several atomic systems are presented
improving previous works. The results here obtained are very close to those
calculated in either the Hartree-Fock and the multi configurational
Hartree-Fock framework.Comment: 8 pages, 3 figure
A Self-Consistent Model for Positronium Formation from Helium Atoms
The differential and total cross sections for electron capture by positrons
from helium atoms are calculated using a first-order distorted wave theory
satisfying the Coulomb boundary conditions. In this formalism a parametric
potential is used to describe the electron screening in a consistent and
realistic manner. The present procedure is self consistent because (i) it
satisfies the correct boundary conditions and post-prior symmetry, and (ii) the
potential and the electron binding energies appearing in the transition
amplitude are consistent with the wave functions describing the collision
system. The results are compared with the other theories and with the available
experimental measurements. At the considered range of collision energies, the
results agree reasonably well with recent experiments and theories.
[Note: This paper will be published on volume 42 of the Brazilian Journal of
Physics
Evolution in intergenerational exchanges between elderly people and their grandchildren in Taiwan; data from a multiple round cross-sectional study from 1993 to 2007
<p>Abstract</p> <p>Background</p> <p>This study aimed to evaluate social evolution in Taiwan in recent decades using the changing pattern of care provided by grandparents for their grandchildren as an indicator.</p> <p>Methods</p> <p>Data from the second, fourth and sixth wave surveys of the <it>Study of Health and Living Status of the Middle-Aged and Elderly in Taiwan </it>were used for the analysis. This survey collected individual characteristics, including age, gender, education, ethnicity, dwelling place, living with partners, co-resident with children, employment status, self-reported health status and their provision of care for their grandchildren. Information about the attitudes toward National Health Insurance (NHI) was further collected in a questionnaire of 1999 following the implementation of NHI in 1995. By elders, we mean persons 60 or more years old. By grandchildren, we mean persons under 16 years of age. First, changes in individual characteristics were compared during these study periods (chi-square test). Then the logistic regression was performed to determine how significantly elders' grandchild-care behavior was associated with their individual characteristics.</p> <p>Results</p> <p>The percentage of elders providing grandchild care increased from 7.7% in 1993 to 13.6% in 1999, and then to 19.4% in 2007. By analysis, significant association was found between behavior in taking care of grandchildren and individuals of lower age, grandmothers, those living with partners or co-residing with children, those unemployed and those with better self-reported health status. And the effect of year was confirmed in the multivariable analysis.</p> <p>Conclusions</p> <p>This study pointed out the changing pattern of elders' behavior in taking care of their grandchildren as the main indicator and their related individual characteristics. We argue the need for improving social security policies in an ageing society. We suggest that the interaction between population policies and those of social welfare, including policies for health care and childcare, should be carefully evaluated.</p
Teaching and Learning of Calculus
This survey focuses on the main trends in the field of calculus education. Despite their variety, the findings reveal a cornerstone issue that is strongly linked to the formalism of calculus concepts and to the difficulties it generates in the learning and teaching process. As a complement to the main text, an extended bibliography with some of the most important references on this topic is included. Since the diversity of the research in the field makes it difficult to produce an exhaustive state-of-the-art summary, the authors discuss recent developments that go beyond this survey and put forward new research questions
Soziale Dienste und Hilfe zwischen Generationen in Europa
Private Hilfen zwischen erwachsenen Generationen bei der Haushaltsführung (z. B. bei Haus- und Gartenarbeiten oder Formalitäten) variieren in Europa stark von Nord nach Süd. Während die Hilfehäufigkeit in nördlichen Ländern wie Schweden oder Dänemark mit ausgebauten sozialen Dienstleistungen bei über einem Drittel der Kind-Eltern-Dyaden liegt, helfen erwachsene Kinder in den Mittelmeerländern nur in ungefähr fünfzehn Prozent der Fälle ihren Eltern. Dagegen verteilt sich die Intensität dieser Hilfeleistungen in umgekehrter Richtung: In den südlichen Ländern unterstützen die relativ wenigen Helfer ihre Eltern zeitintensiver als im Norden. Die Ergebnisse logistischer und linearer Mehrebenenmodelle auf Basis der SHARE-Daten legen nahe, dass neben individuellen Bedürfnissen und Möglichkeiten sowie Familienfaktoren auch kulturell-kontextuelle Strukturen eine entscheidende Rolle für die Wahrscheinlichkeit und Intensität intergenerationaler Hilfe spielen. Die Spezialisierungsthese im Sinne der spezifischen Aufgabenteilung von sozialen Diensten und Familie kann auf die Hilfe für die Eltern in Europa übertragen werden: Je mehr die Familie durch soziale Dienstleistungen bei der Betreuung Bedürftiger entlastet wird, desto eher erbringen die Kinder kurzfristige Unterstützungen – während der öffentliche Sektor eher die besser planbaren, stetigen und zeitintensiven Aufgaben übernimmt
Intergenerational solidarity and conflict
The article deals with intergenerational solidarity as well as the problematic aspects of intergenerational relations, focusing on conflicts. It analyzes interconnection between intergenerational solidarity and conflict. The determinants of solidarity and conflict were identified based on the proposed theoretical model. This model indicates intergenerational relations are not only within family sociology. It added that societal conditions establish a structure for intergenerational relations within the family
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