Towards the Green-Griffiths-Lang conjecture

The Green-Griffiths-Lang conjecture stipulates that for every projective variety X of general type over C, there exists a proper algebraic subvariety of X containing all non constant entire curves f : C $\rightarrow$ X. Using the formalism of directed varieties, we prove here that this assertion holds true in case X satisfies a strong general type condition that is related to a certain jet-semistability property of the tangent bundle TX . We then give a sufficient criterion for the Kobayashi hyperbolicity of an arbitrary directed variety (X,V). This work is dedicated to the memory of Professor Salah Baouendi.Comment: version 2 has been expanded and improved (15 pages

Sur le lemme de Brody

Brody's lemma is a basic tool in complex hyperbolicity. We present a version of it making more precise the localization of an entire curve coming from a diverging sequence of holomorphic discs. As a byproduct we characterize hyperbolicity in terms of an isoperimetric inequality

Factors associated with growth in daily smoking among Indigenous adolescents

North American Indigenous adolescents smoke earlier, smoke more, and are more likely to become regular smokers as adults than youth from any other ethnic group, yet we know very little about their early smoking trajectories. We use multilevel growth modeling across five waves of data from Indigenous adolescents (aged 10-13 years at Wave 1) to investigate factors associated with becoming a daily smoker. Several factors, including number of peers who smoked at Wave 1 and meeting diagnostic criteria for major depressive episode and conduct disorder, were associated with early daily smoking. Only age and increases in the number of smoking peers were associated with increased odds of becoming a daily smoker. © 2012 The Authors. Journal of Research on Adolescence © 2012 Society for Research on Adolescence

Proton and cadmium adsorption by the archaeon Thermococcus zilligii: Generalising the contrast between thermophiles and mesophiles as sorbents

Adsorption by microorganisms can play a significant role in the fate and transport of metals in natural systems. Surface complexation models (SCMs) have been applied extensively to describe metal adsorption by mesophilic bacteria, and several recent studies have extended this framework to thermophilic bacteria. We conduct acid-base titrations and batch experiments to characterise proton and Cd adsorption onto the thermophilic archaeon Thermococcus zilligii. The experimental data and the derived SCMs indicate that the archaeon displays significantly lower overall sorption site density compared to previously studied thermophilic bacteria such Anoxybacillus flavithermus, Geobacillus stearothermophilus, G. thermocatenulatus, and Thermus thermophilus. The thermophilic bacteria and archaea display lower sorption site densities than the mesophilic microorganisms that have been studied to date, which points to a general pattern of total concentration of cell wall adsorption sites per unit biomass being inversely correlated to growth temperature

Effective algebraic degeneracy

We prove that any nonconstant entire holomorphic curve from the complex line C into a projective algebraic hypersurface X = X^n in P^{n+1}(C) of arbitrary dimension n (at least 2) must be algebraically degenerate provided X is generic if its degree d = deg(X) satisfies the effective lower bound: d larger than or equal to n^{{(n+1)}^{n+5}}

Fast Partial Distance Estimation and Applications

We study approximate distributed solutions to the weighted {\it all-pairs-shortest-paths} (APSP) problem in the CONGEST model. We obtain the following results. $1.$ A deterministic $(1+o(1))$-approximation to APSP in $\tilde{O}(n)$ rounds. This improves over the best previously known algorithm, by both derandomizing it and by reducing the running time by a $\Theta(\log n)$ factor. In many cases, routing schemes involve relabeling, i.e., assigning new names to nodes and require that these names are used in distance and routing queries. It is known that relabeling is necessary to achieve running times of $o(n/\log n)$. In the relabeling model, we obtain the following results. $2.$ A randomized $O(k)$-approximation to APSP, for any integer $k>1$, running in $\tilde{O}(n^{1/2+1/k}+D)$ rounds, where $D$ is the hop diameter of the network. This algorithm simplifies the best previously known result and reduces its approximation ratio from $O(k\log k)$ to $O(k)$. Also, the new algorithm uses uses labels of asymptotically optimal size, namely $O(\log n)$ bits. $3.$ A randomized $O(k)$-approximation to APSP, for any integer $k>1$, running in time $\tilde{O}((nD)^{1/2}\cdot n^{1/k}+D)$ and producing {\it compact routing tables} of size $\tilde{O}(n^{1/k})$. The node lables consist of $O(k\log n)$ bits. This improves on the approximation ratio of $\Theta(k^2)$ for tables of that size achieved by the best previously known algorithm, which terminates faster, in $\tilde{O}(n^{1/2+1/k}+D)$ rounds

Factors Associated with Growth in Daily Smoking among Indigenous Adolescents

North American Indigenous adolescents smoke earlier, smoke more, and are more likely to become regular smokers as adults than youth from any other ethnic group yet we know very little about their early smoking trajectories. We use multilevel growth modeling across five waves of data from Indigenous adolescents (aged 10 to 13 years at Wave 1) to investigate factors associated with becoming a daily smoker. Several factors, including number of peers who smoked at Wave 1 and meeting diagnostic criteria for major depressive episode and conduct disorder were associated with early daily smoking. Only age and increases in the number of smoking peers were associated with increased odds of becoming a daily smoker

Factors Associated with Growth in Daily Smoking among Indigenous Adolescents

North American Indigenous adolescents smoke earlier, smoke more, and are more likely to become regular smokers as adults than youth from any other ethnic group yet we know very little about their early smoking trajectories. We use multilevel growth modeling across five waves of data from Indigenous adolescents (aged 10 to 13 years at Wave 1) to investigate factors associated with becoming a daily smoker. Several factors, including number of peers who smoked at Wave 1 and meeting diagnostic criteria for major depressive episode and conduct disorder were associated with early daily smoking. Only age and increases in the number of smoking peers were associated with increased odds of becoming a daily smoker

Testing the recovery of stellar rotation signals from Kepler light curves using a blind hare-and-hounds exercise

We present the results of a blind exercise to test the recoverability of stellar rotation and differential rotation in Kepler light curves. The simulated light curves lasted 1000 days and included activity cycles, Sun-like butterfly patterns, differential rotation and spot evolution. The range of rotation periods, activity levels and spot lifetime were chosen to be representative of the Kepler data of solar like stars. Of the 1000 simulated light curves, 770 were injected into actual quiescent Kepler light curves to simulate Kepler noise. The test also included five 1000-day segments of the Sun's total irradiance variations at different points in the Sun's activity cycle. Five teams took part in the blind exercise, plus two teams who participated after the content of the light curves had been released. The methods used included Lomb-Scargle periodograms and variants thereof, auto-correlation function, and wavelet-based analyses, plus spot modelling to search for differential rotation. The results show that the `overall' period is well recovered for stars exhibiting low and moderate activity levels. Most teams reported values within 10% of the true value in 70% of the cases. There was, however, little correlation between the reported and simulated values of the differential rotation shear, suggesting that differential rotation studies based on full-disk light curves alone need to be treated with caution, at least for solar-type stars. The simulated light curves and associated parameters are available online for the community to test their own methods.Comment: Accepted for publication in MNRAS. Accepted, 13 April 2015. Received, 26 March 2015; in original form, 9 November 201

A Population-Based Serologic Survey of Immunity to Tetanus in the United States

Background. Vaccination rates are frequently considered a surrogate measure of protection. To provide more accurate estimates, serum levels of antibody against tetanus were measured as part of the third National Health and Nutrition Examination Survey (NHANES III), which studied a representative sample of the civilian, noninstitutionalized population of the United States. Methods. We measured tetanus antitoxin using a solid- phase enzyme immunoassay in serum samples from 10,618 persons six years of age and older who were examined during phase 1 of NHANES III in 1988 to 1991. Results. Overall, 69.7 percent of Americans six years of age and older had protective levels of tetanus antibodies (0.15 IU per milliliter). The rate decreased from 87.7 percent among those 6 to 11 years of age to 27.8 percent among those 70 years of age or older. Among children 6 to 16 years of age, 82.2 percent had protective levels of tetanus antibodies, with little variation according to race or ethnicity. More men than women were immune (79.0percent vs. 62.4 percent). Mexican Americans had a significantly lower rate of immunity (57.9 percent, P 0.05) than either non-Hispanic whites (72.7 percent) or non-Hispanic blacks (68.1 percent). Those with a history of military service, higher levels of education, or incomes above the poverty level were more likely to have protective antibody levels. Although the prevalence of immunity declined rapidly starting at the age of 40 years, most of the 107 cases of tetanus (with 20 deaths) reported in 1989 and 1990 occurred in persons 60 years of age or older. Conclusions. Despite the fact that effective vaccines against tetanus have been available since the 1940s, many Americans do not have immunity to tetanus, and the rates are lowest among the elderly. There is an excellent correlation between vaccination rates (96 percent) and immunity (96 percent) among six-year-olds. However, antibody levels decline over time, and one fifth of older children (10 to 16 years of age) do not have protective antibody levels