Sleep Complaints Affecting School Performance at Different Educational Levels

The clear association between reports of sleep disturbance and poor school performance has been documented for sleepy adolescents. This study extends that research to students outside the adolescent age grouping in an associated school setting (98 middle school students, 67 high school students, and 64 college students). Reported restless legs and periodic limb movements are significantly associated with lower GPA's in junior high students. Consistent with previous studies, daytime sleepiness was the sleep variable most likely to negatively affects high school students. Sleep onset and maintenance insomnia were the reported sleep variables significantly correlated with poorer school performance in college students. This study indicates that different sleep disorder variables negatively affect performance at different age and educational levels

Gas gun shock experiments with single-pulse x-ray phase contrast imaging and diffraction at the Advanced Photon Source

The highly transient nature of shock loading and pronounced microstructure effects on dynamic materials response call for {\it in situ}, temporally and spatially resolved, x-ray-based diagnostics. Third-generation synchrotron x-ray sources are advantageous for x-ray phase contrast imaging (PCI) and diffraction under dynamic loading, due to their high photon energy, high photon fluxes, high coherency, and high pulse repetition rates. The feasibility of bulk-scale gas gun shock experiments with dynamic x-ray PCI and diffraction measurements was investigated at the beamline 32ID-B of the Advanced Photon Source. The x-ray beam characteristics, experimental setup, x-ray diagnostics, and static and dynamic test results are described. We demonstrate ultrafast, multiframe, single-pulse PCI measurements with unprecedented temporal ($<$100 ps) and spatial ($\sim$2 $\mu$m) resolutions for bulk-scale shock experiments, as well as single-pulse dynamic Laue diffraction. The results not only substantiate the potential of synchrotron-based experiments for addressing a variety of shock physics problems, but also allow us to identify the technical challenges related to image detection, x-ray source, and dynamic loading

Reduction of energy cost of magnetization switching in a biaxial nanoparticle by use of internal dynamics

A solution to energy-efficient magnetization switching in a nanoparticle with biaxial anisotropy is presented. Optimal control paths minimizing the energy cost of magnetization reversal are calculated numerically as functions of the switching time and materials properties, and used to derive energy-efficient switching pulses of external magnetic field. Hard-axis anisotropy reduces the minimum energy cost of magnetization switching due to the internal torque in the desired switching direction. Analytical estimates quantifying this effect are obtained based on the perturbation theory. The optimal switching time providing a tradeoff between fast switching and energy efficiency is obtained. The energy cost of switching and the energy barrier between the stable states can be controlled independently in a biaxial nanomagnet. This provides a solution to the dilemma between energy-efficient writability and good thermal stability of magnetic memory elements.Comment: 13 pages, 10 figure

190 MeV Proton-Induced Fission

This work was supported by the National Science Foundation Grants NSF PHY 78-22774 A03, NSF PHY 81-14339, and by Indiana Universit

Zastosowanie nieinwazyjnej metody NIR-T/BSS (Near Infra-Red Transillumination-Back Scattering) do monitorowania zmian ukrwienia mózgu w chirurgii naczyń szyjnych

Wstęp. Z roku na rok zwiększa się liczba zabiegów wykonywanych na tętnicach szyjnych. Dotychczas stosowane metody kontroli zmian ukrwienia mózgu wydają się niewystarczające. Szczególnie dotkliwy jest brak możliwości monitorowania podczas zabiegu operacyjnego. Cel pracy. Wykazanie przydatności nowo opracowanej metody transluminacji w bliskiej podczerwieni (NIR-T/BSS) do monitorowania zmian ukrwienia mózgu podczas zabiegu operacyjnego endarterektomii, oceny jego skuteczności, jak również do wspomagania diagnostyki przed zabiegiem. Materiał i metody. Badaniem objęto 50 chorych ze zwężeniem tętnicy szyjnej, u których wykonano zabieg endarterektomii. Wyniki. Zastosowanie metody NIR-T/BSS pozwoliło obiektywnie ocenić krążenie oboczne, wybrać kolejność stron w przypadku zabiegów obustronnych przy takim samym stopniu zwężenia, określonym metodą opartą na efekcie Dopplera, monitorować zmiany ukrwienia mózgu podczas zabiegu operacyjnego oraz ocenić poprawę ukrwienia mózgu po zabiegu. Wnioski. Wstępna ocena wyników uzyskanych za pomocą metody NIR-T/BSS pozwala uznać ją za bardzo przydatną metodę nieinwazyjnego monitorowania zmian ukrwienia mózgu. Technika ta jest łatwa do zastosowania w warunkach operacyjnych, charakteryzuje się wysoką czułością, a otrzymane wyniki korelują z wynikami uzyskanymi innymi metodami (np. Dopplera) oraz z procedurą zabiegu. Przedstawione zapisy mają charakter jakościowy.Background. A steady rising trend is observed in the number of carotid surgeries performed. Methods of monitoring of changes in cerebral blood supply used so far, prove inadequate and insufficient. Of special importance and value would be availability of such monitoring during carotid surgery. Aim of the study. The objective of the current study was evaluation of the applicability and usefulness of a newly devised non-invasive method of Near Infra-Red Transillumination/Backscattering Sounding (NIR-T/BSS) for monitoring of changes in cerebral blood supply in the course of carotid endarterectomy and for assessment of the effectiveness of the surgery, as well as a supplementary diagnostic tool prior to surgical treatment. Material and methods. NIR-T/BSS recordings were made in 50 patients with recognised carotid stenosis, in whom surgical treatment with carotid endarterectomy was performed. Results. Application of the NIR-T/BSS method enabled: A. objective assessment of the collateral circulation, B. selection of the sequence of sides to be operated on in cases of equal bilateral carotid stenosis, as determined with Doppler ultrasound, C. monitoring of the changes in cerebral blood supply during the surgery, and D. post-operative evaluation of the beneficial effect of the surgery.   Conclusions. The early results obtained with the NIR-T/BSS method provide arguments to believe that this method will soon be recognised as highly useful modality in monitoring of the changes in cerebral blood supply. The technique is characterised by high simplicity of use in intra-operative conditions, high sensitivity and congruence of the obtained results with those collected with other methods, as well as with the logic of the physiological reactions. The presented NIR-T/BSS recordings provide qualitative and not quantitative arguments

Uterine NK cells are critical in shaping DC immunogenic functions compatible with pregnancy progression.

Dendritic cell (DC) and natural killer (NK) cell interactions are important for the regulation of innate and adaptive immunity, but their relevance during early pregnancy remains elusive. Using two different strategies to manipulate the frequency of NK cells and DC during gestation, we investigated their relative impact on the decidualization process and on angiogenic responses that characterize murine implantation. Manipulation of the frequency of NK cells, DC or both lead to a defective decidual response characterized by decreased proliferation and differentiation of stromal cells. Whereas no detrimental effects were evident upon expansion of DC, NK cell ablation in such expanded DC mice severely compromised decidual development and led to early pregnancy loss. Pregnancy failure in these mice was associated with an unbalanced production of anti-angiogenic signals and most notably, with increased expression of genes related to inflammation and immunogenic activation of DC. Thus, NK cells appear to play an important role counteracting potential anomalies raised by DC expansion and overactivity in the decidua, becoming critical for normal pregnancy progression

EBT2 Dosimetry of X-rays produced by the electron beam from PFMA-3, a Plasma Focus for medical applications

The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for IORT (IntraOperative Radiation Therapy) applications. A Plasma Focus device is being developed to this aim, to be utilized as an X-ray source. The electron beam is driven to impinge on 50 {\mu}m brass foil, where conversion X-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the X-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.Comment: 10 pages, 14 figure

Entorse de la cheville chez le jeune sportif [Ankle sprain in youth athlete]

Lateral ankle sprain is the most frequent musculoskeletal injury in the young athlete. Myths, dogma and common belief are regularly encountered when discussing this injury, for which the scientific literature does not prevail yet. In the youth, the growing skeleton further influences the diagnosis and therapeutic processes, as well as the healing potential. For the athlete, a fast recovery and return to sports without recurrence are a priority. In this specific context, an integrated management of the ankle sprain in the young athlete must be based on an adequate diagnosis, a sound knowledge of pediatrics pitfalls and peer-reviewed physiotherapy recommendations and consensus statements

Virtual Top-Quark Effects on the H->bb-bar Decay at Next-to-Leading Order in QCD

By means of a heavy-top-quark effective Lagrangian, we calculate the three-loop corrections of O(alpha_s^2 G_F M_t^2) to the H->bb-bar partial decay width of the standard-model Higgs boson with intermediate mass M_H<<2M_t. We take advantage of a soft-Higgs theorem to construct the relevant coefficient functions. We present our result both in the MS-bar and on-shell schemes of mass renormalization. The MS-bar formulation turns out to be favourable with regard to the convergence behaviour. We also test a recent idea concerning the naive non-abelianization of QCD.Comment: 8 pages (Latex), 5 figures (Postscript