43 research outputs found
FP-17-22 Crossover in the Median Age at First Marriage and First Birth: Thirty-Five Years of Change
Intraspecific diversity of the rhizodeposition of Lupinus angustifolius L. regarding the phosphorus mobilization in the soil
The cropping of lupines (Lupinus spp.) for protein production is rising worldwide. The growth of lupines is often limited by P deficiency, caused by low P bioavailability in soils. The rhizodeposition is a leading control of the P mobilization in the soil, i.e. especially by the release of phosphatases and organic acids. In the present study 20 genotypes of L. angustifolius (19 accessions from different geographic origins and the cultivar Boruta) were tested on their molecular-chemical composition of the rhizodeposition in P-deficiency by pyrolysis-field ionisation mass spectrometry (Py-FIMS) and on the phosphatase and Ă-glucosidase activities in the rhizosphere soil.
The intraspecific diversity of the composition of the rhizodeposits was especially large for the relative abundance of carbohydrates and in this way in a specific impact on the microbial activity in the rhizosphere by selective promotion under some genotypes by easily available C sources for the microbial rhizosphere community. This was confirmed by a large variation in the thermal stability of the rhizodeposits of different genotypes, a varying pH level in identical cultivation conditions and in varying activities of alkaline and acid phosphomonoesterases and Ă-glucosidase in the rhizosphere. Furthermore, the data revealed a strong variation in the release of alkaloids into the rhizosphere during the growth with a further impact on the microbial activity. In conclusion, the use of the quality of the rhizodeposition as an indicator of the potential for P mobilization in P-deficient soils highlighted a broad intraspecific diversity within L. angustifolius. This is a promising basis for a selection of highly P efficient genotypes within this species for further breeding strategies of productive cultivars
Measurement of the Nucleon Structure Function F2 in the Nuclear Medium and Evaluation of its Moments
We report on the measurement of inclusive electron scattering off a carbon
target performed with CLAS at Jefferson Laboratory. A combination of three
different beam energies 1.161, 2.261 and 4.461 GeV allowed us to reach an
invariant mass of the final-state hadronic system W~2.4 GeV with four-momentum
transfers Q2 ranging from 0.2 to 5 GeV2. These data, together with previous
measurements of the inclusive electron scattering off proton and deuteron,
which cover a similar continuous two-dimensional region of Q2 and Bjorken
variable x, permit the study of nuclear modifications of the nucleon structure.
By using these, as well as other world data, we evaluated the F2 structure
function and its moments. Using an OPE-based twist expansion, we studied the
Q2-evolution of the moments, obtaining a separation of the leading-twist and
the total higher-twist terms. The carbon-to-deuteron ratio of the leading-twist
contributions to the F2 moments exhibits the well known EMC effect, compatible
with that discovered previously in x-space. The total higher-twist term in the
carbon nucleus appears, although with large systematic uncertainites, to be
smaller with respect to the deuteron case for n<7, suggesting partial parton
deconfinement in nuclear matter. We speculate that the spatial extension of the
nucleon is changed when it is immersed in the nuclear medium.Comment: 37 pages, 15 figure
Is it even possible to treat boys and girls in the same way? Gender bias in the 1990\u27s classroom
In the belief that gender bias still occurs in the 1990\u27s classroom, this investigation was carried out to explore some of the ways of committing bias based on a student\u27s gender. Additionally, some suggestions were made as to alternative equitable behaviors for teachers in today\u27s classrooms. As stated in the title of this work, the central question in the researcher\u27s mind was, Is it even possible to treat students in the same way?
The data included in this study was obtained from observing seven teachers in two schools in two western states. These schools are both located in rural communities. Williams Elementary (fictitious name) has a grant to inform teachers about gender bias, its effects and some ways to eliminate it from teaching behavior. Interviews were conducted with two teachers and a principal. The observation form developed for this study covered ten areas of concern when addressing the issue of gender bias. The interviews answered many of the specific questions regarding these issues, while the observation focused on whether or not teachers\u27 behavior matched their philosophies on the matter.
From the interviews, it was learned that the teachers of Williams Elementary try hard at, and are quite successful at, having non-stereotyped or biased classes. However, the observations showed that some biased practices still exist.
Although there has been much ground gained concerning equity for women and girls, there remains more to do. Alternating calling on boys and girls will not achieve gender equity in the classroom. Objective yet simple-to-implement methods are needed for teachers to help insure equity in their classrooms
An Online Monitoring System for the Screening of Stationary-Phase Promoters in E. Coli using GFP as a Reporter Protein
Bettenworth F, Miksch G, Fries K, et al. An Online Monitoring System for the Screening of Stationary-Phase Promoters in E. Coli using GFP as a Reporter Protein.; 2005
Family Management Practices and Positive Youth Development in Stepfamilies and SingleâMother Families
Objective
To determine how engagement in family management practices (i.e., parentâyouth closeness, knowledge of youth\u27s friends, shared family meals, and media monitoring) is associated with positive developmental outcomes for youth living in diverse family structures.
Background
As patterns of unmarried childbearing, cohabitation, divorce, and remarriage have changed in the United States, youth increasingly live in diverse family structures. Limited research, however, addresses positive youth development in these families. Specific family tasks and caregiver constellations in the home may mean that youth in different family structures benefit differently from family management practices.
Method
Using data from 9,131 households with a 12- to 17-year-old child in the 2011â2012 National Survey of Children\u27s Health, structural equation modeling was used to test whether four family management practices were associated with two positive youth developmental outcomes (flourishing and extracurricular activity participation). Multigroup analyses tested for differences in the associations across family structures.
Results
Family management practices were generally positively associated with positive youth development. The strength of associations between specific family management practices and positive youth developmental outcomes, however, varied across family structures, suggesting that practices may have differing effectiveness depending on family context.
Conclusion
Understanding mechanisms that promote positive youth developmental outcomes in diverse family structures and how mechanisms may function differently across family contexts can broaden the sophistication of family theories and interventions