A relative Hilbert-Mumford criterion

We generalize the classical Hilbert-Mumford criteria for GIT (semi-)stability in terms of one parameter subgroups of a linearly reductive group G over a field k, to the relative situation of an equivariant, projective morphism X -> Spec A to a noetherian k-algebra A. We also extend the classical projectivity result for GIT quotients: the induced morphism X^ss/G -> Spec A^G is projective. As an example of applications to moduli problems, we consider degenerations of Hilbert schemes of points.Comment: v4: minor correction

Gauged Supergravity and Singular Calabi-Yau Manifolds

Compactifications of M-theory on singular manifolds contain additional charged massless states descending from M-branes wrapped on vanishing cycles. We construct the first explicit example of a complete supergravity Lagrangian that includes such extra states. This is done for a compactification on a Calabi-Yau threefold that develops a genus zero curve of A_1 singularities at the boundary of the K\"ahler cone with a resulting SU(2) gauge symmetry enhancement. The corresponding SU(2) gauged supergravity Lagrangian includes two charged and two neutral vector multiplets, and turns out to be uniquely fixed by the Calabi-Yau geometry and by the effective ungauged Lagrangian describing the Coulomb branch. One can see explicitly how resolving the singularity corresponds to a supersymmetric Higgs effect in the gauged supergravity description. The elementary transformation relating the two families of smooth Calabi-Yau resolutions of the singularity acts as the SU(2) Weyl twist. The resulting structure appears to be very rigid and is likely to apply to other types of singularities and manifolds as well.Comment: 37 pages, no figures, JHEP3, minor typos corrected, one reference added, Appendix A streamline

The stimulating effect of bright light on physical performance depends on internal time.

The human circadian clock regulates the daily timing of sleep, alertness and performance and is synchronized to the 24-h day by the environmental light-dark cycle. Bright light exposure has been shown to positively affect sleepiness and alertness, yet little is known about its effects on physical performance, especially in relation to chronotype. We, therefore, exposed 43 male participants (mean age 24.5 yrs ± SD 2.3 yrs) in a randomized crossover study to 160 minutes of bright (BL: ≈ 4.420 lx) and dim light (DL: ≈ 230 lx). During the last 40 minutes of these exposures, participants performed a bicycle ergometer test. Time-of-day of the exercise sessions did not differ between the BL and DL condition. Chronotype (MSF(sc), mid-sleep time on free days corrected for oversleep due to sleep debt on workdays) was assessed by the Munich ChronoType Questionnaire (MCTQ). Total work was significantly higher in BL (median 548.4 kJ, min 411.82 kJ, max 875.20 kJ) than in DL (median 521.5 kJ, min 384.33 kJ, max 861.23 kJ) (p = 0.004) going along with increased exhaustion levels in BL (blood lactate (+12.7%, p = 0.009), heart rate (+1.8%, p = 0.031), and Borg scale ratings (+2.6%, p = 0.005)) in all participants. The differences between total work levels in BL and DL were significantly higher (p = 0.004) if participants were tested at a respectively later time point after their individual mid-sleep (chronotype). These novel results demonstrate, that timed BL exposure enhances physical performance with concomitant increase in individual strain, and is related not only to local (external) time, but also to an individual's internal time

A GIT construction of degenerations of Hilbert schemes of points

We present a Geometric Invariant Theory (GIT) con-struction which allows us to construct good projective degenerationsof Hilbert schemes of points for simple degenerations. A comparisonwith the construction of Li and Wu shows that our GIT stack andthestack they construct are isomorphic, as are the associated coarse mod-uli schemes. Our construction is sufficiently explicit to obtain goodcontrol over the geometry of the singular fibres. We illustrate thisby giving a concrete description of degenerations of degreenHilbertschemes of a simple degeneration with two components

Evaluation and selection of lower limb lymphedema patients for lymphaticovenular anastomosis: A prospective study

Background: Lymphaticovenular anastomosis (LVA) with supramicrosurgical technique has recently gained popularity as a treatment method for patients with lymphedema. The aim of this study was to prospectively evaluate objective changes in leg volume in patients operated with LVA for lymphedema in the lower extremity, and to find positive predictors for the treatment method to facilitate the location of the venules and lymphatic vessels. Patients & Methods: 31 consecutive patients with lymphedema in the lower extremity and positive pitting test were examined with lymphoscintigraphy and indocyanine green (ICG) lymphography. The causes of the lymphedema were either cancer or unknown cause/primary lymphedema. Fourteen of the patients with pathological lymphangiographic patterns were chosen for surgery and 12 of them were operated with one to four LVAs each. The lymphedema volume in the lower extremity was measured preoperatively, 6- and 12 months after surgery according to the truncated cone formula with the patient \u301s contralateral leg used as control. Ten patients had unilateral lymphedema and two patients had bilateral lymphedema. Results: Five of 12 patients showed between 1-8 % edema reductions in the lower extremity after 12 months. With examination considering edema duration, number of anastomoses, radiotherapy and lymph node dissection we found a 6,2 % difference in edema reduction between patients who had undergone lymph node dissection and those who had not (p=0.03). Conclusions: The current study indicates that supramicrosurgery with LVA may reduce edema volumes, where the most distinctive positive predictor for edema reduction with LVAs was previous lymph node dissection

The geometry of degenerations of Hilbert schemes of points

Given a strict simple degeneration $f \colon X\to C$ the first three authors previously constructed a degeneration $I^n_{X/C} \to C$ of the relative degree $n$ Hilbert scheme of $0$-dimensional subschemes. In this paper we investigate the geometry of this degeneration, in particular when the fibre dimension of $f$ is at most $2$. In this case we show that $I^n_{X/C} \to C$ is a dlt model. This is even a good minimal dlt model if $f \colon X \to C$ has this property. We compute the dual complex of the central fibre $(I^n_{X/C})_0$ and relate this to the essential skeleton of the generic fibre. For a type II degeneration of $K3$ surfaces we show that the stack ${\mathcal I}^n_{X/C} \to C$ carries a nowhere degenerate relative logarithmic $2$-form. Finally we discuss the relationship of our degeneration with the constructions of Nagai.Comment: 53 pages. To appear in J. Algebraic Geo

A cluster randomised school-based lifestyle intervention programme for the prevention of childhood obesity and related early cardiovascular disease (JuvenTUM 3)

<p>Abstract</p> <p>Background</p> <p>Childhood obesity is not only associated with adult obesity but also with increased risk of adult onset of type 2 diabetes and subsequent coronary heart disease. The potential effects of school-based health intervention programmes on cardiovascular risk and surrogate markers are unclear, as only few studies have attempted to investigate a complete risk profile including a detailed laboratory analysis or micro- and macrovascular function. In this study a comprehensive school-based randomized intervention programme will be investigated in 10-14-year old children addressing the influence of lifestyle intervention on inactivity, cardiometabolic risk factors and early signs of vascular disease.</p> <p>Methods/Design</p> <p>15 secondary schools in Southern Germany are randomly assigned to intervention or control schools. Children in the fifth grade (10-11 years) will be observed over four years. The study combines a school-based with a home-based approach, aiming at children, teachers and parents. The main components are weekly lifestyle-lessons for children, taught by regular classroom teachers to increase physical activity in- and outside of school, to improve eating patterns at school and at home, to reduce media consumption and to amplify well-being. In 4-6 annual meetings, teachers receive information about health-related topics with worksheets for children and supporting equipment, accounting for school-specific needs and strategies. Parents' trainings are provided on a regular basis.</p> <p>All examinations are performed at the beginning and at the end of every school year. Anthropometry includes measurements of BMI, waist and upper arm circumferences, skinfold thickness as well as peripheral blood pressure. Blood sampling includes lipid parameters, insulin, glucose, hsCRP, adiponectin, and IL-6 as well as testosteron and estrogen to determine maturation status. Vascular function is non-invasively assessed by measuring arterial stiffness in large arteries using a sphygmograph and by analysing arteriolar and venular diameters in the retinal microcirculation using a non-mydriatric vessel analyser. A questionnaire is filled out to determine daily physical activity, motivational factors, dietary habits, quality of life (KINDL-R) and socio-economic data. Physical fitness is assessed by a six-item test battery.</p> <p>Discussion</p> <p>Our study aims to provide a feasible long-term intervention strategy to re-establish childhood health and to prevent obesity-related cardiovascular dysfunction in children.</p> <p>Trial Registration</p> <p><a href="http://www.clinicaltrials.gov/ct2/show/NCT00988754">NCT00988754</a></p