Is 8:30 a.m. Still Too Early to Start School? A 10:00 a.m. School Start Time Improves Health and Performance of Students Aged 13-16.

While many studies have shown the benefits of later school starts, including better student attendance, higher test scores, and improved sleep duration, few have used starting times later than 9:00 a.m. Here we report on the implementation and impact of a 10 a.m. school start time for 13 to 16-year-old students. A 4-year observational study using a before-after-before (A-B-A) design was carried out in an English state-funded high school. School start times were changed from 8:50 a.m. in study year 0, to 10 a.m. in years 1-2, and then back to 8:50 a.m. in year 3. Measures of student health (absence due to illness) and academic performance (national examination results) were used for all students. Implementing a 10 a.m. start saw a decrease in student illness after 2 years of over 50% (p < 0.0005 and effect size: Cohen's d = 1.07), and reverting to an 8:50 a.m. start reversed this improvement, leading to an increase of 30% in student illness (p < 0.0005 and Cohen's d = 0.47). The 10:00 a.m. start was associated with a 12% increase in the value-added number of students making good academic progress (in standard national examinations) that was significant (<0.0005) and equivalent to 20% of the national benchmark. These results show that changing to a 10:00 a.m. high school start time can greatly reduce illness and improve academic performance. Implementing school start times later than 8:30 a.m., which may address the circadian delay in adolescents' sleep rhythms more effectively for evening chronotypes, appears to have few costs and substantial benefits

Machine Learning Tips and Tricks for Power Line Communications

4openopenTonello A.M.; Letizia N.A.; Righini D.; Marcuzzi F.Tonello, A. M.; Letizia, N. A.; Righini, D.; Marcuzzi, F

Detection and origin of bacteria in platelet concentrates

Savelkoul, P.H.M. [Promotor]Korte, D. de [Copromotor]Pettersson, A.M. [Copromotor

Protein kinase D enzymes are dispensable for proliferation, survival and antigen receptor-regulated NFκB activity in vertebrate B-cells

To investigate the importance of protein kinase D (PKD) enzymes we generated a PKD-null DT40 B-lymphocyte cell line. Previously we have shown that PKDs have an essential role in regulating class II histone deacetylases in DT40 B-cells [Matthews, S.A., Liu, P., Spitaler, M., Olson, E.N., McKinsey, T.A., Cantrell, D.A. and Scharenberg, A.M. (2006) Essential role for protein kinase D family kinases in the regulation of class II histone deacetylases in B lymphocytes. Mol. Cell Biol. 26, 1569–1577]. We now show that PKDs are also required to regulate HSP27 phosphorylation in DT40 B-cells. However, in contrast to previous observations in other cell types, PKD enzymes do not regulate basic cellular processes such as proliferation or survival responses, nor NFκB transcriptional activity downstream of the B cell antigen receptor. Thus, PKDs have a selective role in DT40 B-cell biology

Supported liquid membranes: stabilization by gelation

A new method has been developed to increase the stability of supported liquid membranes. By applying a homogeneous gel network in the pores of the support both the mechanical stability (against liquid displacement) and the long term permeability increase substantially. The flux decreases only slightly because of the open structure of the gel network. A second technique, by which a thin dense gel layer is applied to the feed side of the membrane, results in a specific suppression of the formation of emulsion droplets. The stability of the membrane increases by this treatment to values which are very promising

Nitrate removal using supported liquid membranes: transport mechanism

A new method is developed for the removal of nitrate ions from water. Nitrate ions can be removed from water almost completely, with a mobile carrier, by counter-transport of chloride ions through a supported liquid membrane. The transport characteristics of this process, in which the water phases are flowing parallel to flat membranes, are described. The results show that depending on the experimental conditions the flux is determined by the diffusion of the carrier through the membrane or by the diffusion of the nitrate ions through a laminar water layer at the feed side. The selectivity of the membrane, which depends on the type of the organic solvent, determines the influence of the chloride concentration in the stripping phase on the membrane flux. Furthermore the effect of carrier concentration is investigated

Daubenya alba (Hyacinthaceae, tribe Massonieae), a new species from the Roggeveld, Northern Cape Province

Daubenya alba A.M. van der Merwe, from the edge of the Roggeveld escarpment in the Northern Cape Province, is described as a new species. It resembles D. capensis (Schltr.) A.M. van der Merwe & J.C. Manning in leaf shape, floral structure and the presence of a staminal tube, but is distinguished by its delicate white to pale lilac flowers and lack of a staminal disc