The Fission Yeast S-Phase Cyclin Cig2 Can Drive Mitosis [preprint]

Commitment to mitosis is regulated by cyclin-dependent kinase (CDK) activity. In the fission yeast Schizosaccharomyces pombe, the major B-type cyclin, Cdc13, is necessary and sufficient to drive mitotic entry. Furthermore, Cdc13 is also sufficient to drive S phase, demonstrating that a single cyclin can regulate alternating rounds of replication and mitosis and providing the foundation of the quantitative model of CDK function. It has been assumed that Cig2, a B-type cyclin expressed only during S-phase and incapable of driving mitosis in wild-type cells, was specialized for S-phase regulation. Here, we show that Cig2 is capable of driving mitosis. Cig2/CDK activity drives mitotic catastrophe -- lethal mitosis in inviably small cells -- in cells that lack CDK inhibition by tyrosine-phosphorylation. Moreover, Cig2/CDK can drive mitosis in the absence of Cdc13/CDK activity. These results demonstrate that in fission yeast, not only can the presumptive M-phase cyclin drive S phase, but the presumptive S-phase cyclin can drive M phase, further supporting the quantitative model of CDK function. Furthermore, these results provide an explanation, previously proposed on the basis of computation analyses, for the surprising observation that cells expressing a single-chain Cdc13-Cdc2 CDK do not require Y15 phosphorylation for viability. Their viability is due to the fact that in such cells, which lack Cig2/CDK complexes, Cdc13/CDK activity is unable to drive mitotic catastrophe

Adsorption of malachite green and alizarin red s dyes using fe-btc metal organic framework as adsorbent

Synthetic organic dyes are widely used in various industrial sectors but are also among the most harmful water pollutants. In the last decade, significant efforts have been made to develop improved materials for the removal of dyes from water, in particular, on nanostructured adsorbent materials. Metal organic frameworks (MOFs) are an attractive class of hybrid nanostructured materials with an extremely wide range of applications including adsorption. In the present work, an iron-based Fe-BTC MOF, prepared according to a rapid, aqueous-based procedure, was used as an adsorbent for the removal of alizarin red S (ARS) and malachite green (MG) dyes from water. The synthesized material was characterized in detail, while the adsorption of the dyes was monitored by UV-Vis spectroscopy. An optimal adsorption pH of 4, likely due to the establishment of favor-able interactions between dyes and Fe-BTC, was found. At this pH and at a temperature of 298 K, adsorption equilibrium was reached in less than 30 min following a pseudo-second order kinetics, with k” of 4.29 × 10−3 and 3.98 × 10−2 g∙mg−1 min−1 for ARS and MG, respectively. The adsorption isotherm followed the Langmuir model with maximal adsorption capacities of 80 mg∙g−1 (ARS) and 177 mg∙g−1 (MG), and KL of 9.30∙103 L∙mg−1 (ARS) and 51.56∙103 L∙mg−1 (MG)

Chaoticity and Shell Effects in the Nearest-Neighbor Distributions

Statistics of the single-particle levels in a deformed Woods-Saxon potential is analyzed in terms of the Poisson and Wigner nearest-neighbor distributions for several deformations and multipolarities of its surface distortions. We found the significant differences of all the distributions with a fixed value of the angular momentum projection of the particle, more closely to the Wigner distribution, in contrast to the full spectra with Poisson-like behavior. Important shell effects are observed in the nearest neighbor spacing distributions, the larger the smaller deformations of the surface multipolarities.Comment: 10 pages and 9 figure

The Impact of Worksite Weight-Related Social Norms on Associated Behaviors

Objective: To assess the association between descriptive social norms for weight and weight-related behaviors and associated behaviors at the worksite. Design and Sample: Baseline data from site-randomized trial of a worksite ecological intervention for weight control; 12 public high schools in central Massachusetts; Sample of 844 employees enrolled (~ 2/3 of all employees). Conclusions: Associations of weight loss and eating social norms with behavior; Unique from social support; No association of physical activity social norms with physical activity; May be little opportunity for and therefore little exposure to physical activity during the workday; Results support the development of weight loss interventions that address social norms for weight loss and eating behaviors at work

Drinking to Cope is Uniquely Associated with Less Specific and Bleaker Future Goal Generation in Young Hazardous Drinkers

This is the final version. Available on open access from Springer via the DOI in this recordGroups with mental health and/or substance use problems generate less detailed descriptions of their future goals. As substance use to cope with negative affect is common to both groups, this characteristic might be uniquely associated with less specific goal descriptions. To test this prediction, 229 past year hazardous drinking undergraduates aged 18–25 years wrote about three positive future life goals in an open-ended survey, before reporting their internalizing (anxiety and depression) symptoms, alcohol dependence severity and motivations for drinking: coping, conformity, enhancement and social. Future goal descriptions were experimenter-rated for detail specificity, and participant-self-rated for positivity, vividness, achievability, and importance. Effort in goal writing was indexed by time spent writing and total word count. Multiple regression analyses revealed that drinking to cope was uniquely associated with the production of less detailed goals, and lower self-rated positivity and vividness of goals (achievability and importance were also marginally lower), over and above internalizing symptoms, alcohol dependence severity, drinking for conformity, enhancement and social motives, age, and gender. However, drinking to cope was not uniquely associated with reduced effort in writing goals: time spent and word count. In sum, drinking to cope with negative affect is a unique characteristic predicting the generation of less detailed and bleaker (less positive and vivid) future goals, and this is not due to lower effort in reporting. Future goal generation may play a role in the aetiology of comorbidity of mental health and substance use problems, and therapeutic targeting of goal generation might benefit both conditions.Alcohol Change UKMedical Research Council (MRC

Analytical perturbative approach to periodic orbits in the homogeneous quartic oscillator potential

We present an analytical calculation of periodic orbits in the homogeneous quartic oscillator potential. Exploiting the properties of the periodic Lam{\'e} functions that describe the orbits bifurcated from the fundamental linear orbit in the vicinity of the bifurcation points, we use perturbation theory to obtain their evolution away from the bifurcation points. As an application, we derive an analytical semiclassical trace formula for the density of states in the separable case, using a uniform approximation for the pitchfork bifurcations occurring there, which allows for full semiclassical quantization. For the non-integrable situations, we show that the uniform contribution of the bifurcating period-one orbits to the coarse-grained density of states competes with that of the shortest isolated orbits, but decreases with increasing chaoticity parameter $\alpha$.Comment: 15 pages, LaTeX, 7 figures; revised and extended version, to appear in J. Phys. A final version 3; error in eq. (33) corrected and note added in prin

Analytic approach to bifurcation cascades in a class of generalized H\'enon-Heiles potentials

We derive stability traces of bifurcating orbits in H\'enon-Heiles potentials near their saddlesComment: LaTeX revtex4, 38 pages, 7 PostScript figures, 2 table

Community Perspectives on the Impact of Climate Change on Health in Nunavut, Canada

The purpose of this study was to explore community perspectives on the most important ways that climate change is affecting the health of northern peoples. The study was conducted in Iqaluit, Nunavut, using a participatory action approach and the photovoice research method. Participants identified themes and patterns in the data and developed a visual model of the relationships between the themes identified. Five themes emerged from the data: the direct impacts of climate change on the health of individuals and communities, the transition from past climates to future climates, necessary adaptation to the changing climate in the North, the call to action (individual, regional, and national), and reflection on the past and changing knowledge systems. A climate change and health model was developed to illustrate the relationships between the themes. Participants in this study conceptualized health and climate change broadly. Participants believed that by engaging in a process of ongoing reflection, and by continually incorporating new knowledge and experiences into traditional knowledge systems, communities may be better able to adapt and cope with the challenges to health posed by climate change.L’objectif de cette étude consistait à explorer diverses perspectives communautaires quant aux manières les plus importantes dont le changement climatique a des incidences sur la santé des gens du Nord. L’étude a été réalisée à Iqaluit, au Nunavut, au moyen d’une méthode d’action et de recherche participative faisant appel à la « photovoice ». Les participants ont déterminé les thèmes de même que les tendances caractérisant les données, puis ont abouti à un modèle visuel pour établir des relations entre les thèmes ainsi déterminés. Les données ont donné lieu à la formulation de cinq thèmes, soit les incidences directes du changement climatique sur la santé des gens et des collectivités; la transition des anciens climats aux nouveaux climats; l’adaptation nécessaire au climat changeant dans le Nord; un appel à l’action (individuel, régional et national); et une réflexion sur les systèmes de savoir du passé qui sont en pleine évolution. Ensuite, un modèle de changement climatique et de santé a été élaboré dans le but d’illustrer les liens existant entre les divers thèmes. Les participants à cette étude ont conceptualisé le changement climatique et ses incidences sur la santé à grande échelle. Ils croyaient qu’en s’adonnant à un processus de réflexion continue et qu’en intégrant constamment de nouvelles connaissances et expériences aux systèmes de savoir traditionnel, les collectivités pourraient être mieux placées pour s’adapter et relever les défis posés par le changement climatique en matière de santé

The COBE Diffuse Infrared Background Experiment Search for the Cosmic Infrared Background: I. Limits and Detections

The DIRBE on the COBE spacecraft was designed primarily to conduct systematic search for an isotropic CIB in ten photometric bands from 1.25 to 240 microns. The results of that search are presented here. Conservative limits on the CIB are obtained from the minimum observed brightness in all-sky maps at each wavelength, with the faintest limits in the DIRBE spectral range being at 3.5 microns (\nu I_\nu < 64 nW/m^2/sr, 95% CL) and at 240 microns (\nu I_\nu < 28 nW/m^2/sr, 95% CL). The bright foregrounds from interplanetary dust scattering and emission, stars, and interstellar dust emission are the principal impediments to the DIRBE measurements of the CIB. These foregrounds have been modeled and removed from the sky maps. Assessment of the random and systematic uncertainties in the residuals and tests for isotropy show that only the 140 and 240 microns data provide candidate detections of the CIB. The residuals and their uncertainties provide CIB upper limits more restrictive than the dark sky limits at wavelengths from 1.25 to 100 microns. No plausible solar system or Galactic source of the observed 140 and 240 microns residuals can be identified, leading to the conclusion that the CIB has been detected at levels of \nu I_\nu = 25+-7 and 14+-3 nW/m^2/sr at 140 and 240 microns respectively. The integrated energy from 140 to 240 microns, 10.3 nW/m^2/sr, is about twice the integrated optical light from the galaxies in the Hubble Deep Field, suggesting that star formation might have been heavily enshrouded by dust at high redshift. The detections and upper limits reported here provide new constraints on models of the history of energy-releasing processes and dust production since the decoupling of the cosmic microwave background from matter.Comment: 26 pages and 5 figures, accepted for publication in the Astrophyical Journa