844 research outputs found

    Degenerate Elastic Networks

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    We minimize a linear combination of the length and the L2-norm of the curvature among networks in Rd belonging to a given class determined by the number of curves, the order of the junctions, and the angles between curves at the junctions. Since this class lacks compactness, we characterize the set of limits of sequences of networks bounded in energy, providing an explicit representation of the relaxed problem. This is expressed in terms of the new notion of degenerate elastic networks that, rather surprisingly, involves only the properties of the given class, without reference to the curvature. In the case of d= 2 we also give an equivalent description of degenerate elastic networks by means of a combinatorial definition easy to validate by a finite algorithm. Moreover we provide examples, counterexamples, and additional results that motivate our study and show the sharpness of our characterization

    Life cycle of the pelagic goby Aphia minuta (Pisces: Gobiidae)

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    Reproductive aspects of the transparent goby Aphia minuta (n=2977, 14-45 mm total length (TL)) were studied in Majorcan waters, western Mediterranean, during the fishing season (December to April) from 1985 to 1993. Male:female sex ratio was 1:1. Size at first maturity was 38 mm TL for females and 34 mm TL for males. Oocyte size-frequency distribution indicated that A. minuta is a single spawner. Fecundity of A. minuta ranged from 935 to 2648 oocytes. The breeding season extended from December to April with a peak in March. After a single reproduction at 5-6 months of age, most of the specimens disappeared from the fishing areas. Recruitment to the fishing area occurred in late December and early January (14-24 mm TL, age 2-3 months). On the other hand, the hatch date back-calculated from the age in days and the date of capture of individuals of A. minuta during the fishing season, indicated a spawning peak in autumn (September-October), six months after the peak of observed spawning. Schools of A. minuta were detected by acoustic methods, during the fishing season (winter-spring) in fishing areas (5-40 m depth), principally inside bays, and during the rest of the year (summer and autumn) in deeper areas (40-90 m), outside bays, with water temperatures between 13 and 16ºC and a high seasonal productivity in each depth range. Therefore, we propose that A. minuta has two annual cohorts in the western Mediterranean, corresponding to two main spawning in spring and autumn, respectively. Life history pattern indicated that we only know the winter cohort resulting from the autumn spawning. Meanwhile the summer cohort (spring spawning) grows and reproduces in deeper areas not being targeted by the fishery. Indirect validation is provided from information from other areas. The relevance of the life cycle is discussed in relation to fishery managementPublicado

    Necrosis as Programmed Cell Death

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    The process of cell death is the mechanism through which organisms eliminate useless cells. Hence, it is a normal process that maintains homeostasis. Cell removal can be effectuated by several pathways that involve complex and regulated molecular events specific to each type of cell death. Diverse studies have evidenced different types of cell death: apoptosis, autophagy, and necrosis. This chapter presents a brief review of the apoptotic and autophagic cell death processes but focuses attention primarily on necrosis because it has previously been considered an accidental and uncontrolled form of cell death. More recent evidence, however, has shown that, under certain circumstances, necrosis is conducted by a controlled program called necroptosis, which is now included as a programmed cell death process

    Structure of the thioredoxin-like domain of yeast glutaredoxin 3

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    Yeast Grx3 is involved in iron-responsive transcription regulation. The single active site thiol of the thioredoxin-like domain is in a flexible surface loop as suggested by its partial disorder

    Inestabilidad patelofemoral en niños con Síndrome de Down

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    La inestabilidad patelofemoral en el síndrome de Down se presenta en el contexto de hiperlaxitud e inmadurez esquelética suponiendo un reto en el tratamiento. Nuestro objetivo es valorar el resultado clínico-funcional de la cirugía de partes blandas, en estos pacientes hiperlaxos e inmaduros esqueléticamente. Hemos revisado retrospectivamente a los pacientes con síndrome de Down e inmadurez esquelética intervenidos por inestabilidad patelofemoral con seguimiento hasta el cierre fisario. Seis pacientes (9 rodillas) con media de edad de 12,4 años fueron incluidos. El grado de inestabilidad patelofemoral prequirúrgica (clasificación de Dugdale) mostró 1 (11,1%) caso grado 2; 2 (22,2%) casos grado 3 y 6 (66,6%) casos grado 4. El grado de función patelar (según Insall) al alcanzar la madurez esquelética fue malo en un caso (recidiva de la luxación), bueno en 2 y excelente en 6. En definitiva, los procedimientos sobre partes blandas pueden ser suficientes en pacientes con síndrome de Down.Patelofemoral instability in Down syndrome´s patients appears in hiperlaxity and open physis context. Our aim is to make a retrospective clinical-functional assessment of the soft tissue procedure treatment of patellofemoral instability in patients with Down Syndrome skeletally immature (open physeal), following them until the physeal closure. We have included six patients (9 knees) with a mean age of 12.4 years old. Patellar instability (Dugdale´s classification) distribution was 1 (11.1%) cases degree ll; 2 (22.2%) cases degree lll and 6 (66.6%) cases degree IV. Patellar function assessed by Insall score at follow up was excellent in 6 of the cases, good in 2 cases and bad in one case (recurrent dislocation). In summary, a proximal soft tissues procedure in Down syndrome patients could be enough for patellar instability treatment

    Measurements of Isoprene-Derived Organosulfates in Ambient Aerosols by Aerosol Time-of-Flight Mass Spectrometry—Part 2: Temporal Variability and Formation Mechanisms

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    Organosulfate species have recently gained attention for their potentially significant contribution to secondary organic aerosol (SOA); however, their temporal behavior in the ambient atmosphere has not been probed in detail. In this work, organosulfates derived from isoprene were observed in single particle mass spectra in Atlanta, GA during the 2002 Aerosol Nucleation and Characterization Experiment (ANARChE) and the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS). Real-time measurements revealed that the highest organosulfate concentrations occurred at night under a stable boundary layer, suggesting gas-to-particle partitioning and subsequent aqueous-phase processing of the organic precursors played key roles in their formation. Further analysis of the diurnal profile suggests possible contributions from multiple production mechanisms, including acid-catalysis and radical-initiation. This work highlights the potential for additional SOA formation pathways in biogenically influenced urban regions to enhance the organic aerosol burden

    Measurements of Isoprene-Derived Organosulfates in Ambient Aerosols by Aerosol Time-of-Flight Mass Spectrometry - Part 1: Single Particle Atmospheric Observations in Atlanta

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    Organosulfate species have recently been identified as a potentially significant class of secondary organic aerosol (SOA) species, yet little is known about their behavior in the atmosphere. In this work, organosulfates were observed in individual ambient aerosols using single particle mass spectrometry in Atlanta, GA during the 2002 Aerosol Nucleation and Characterization Experiment (ANARChE) and the 2008 August Mini-Intensive Gas and Aerosol Study (AMIGAS). Organosulfates derived from biogenically produced isoprene were detected as deprotonated molecular ions in negative-ion spectra measured by aerosol time-of-flight mass spectrometry; comparison to high-resolution mass spectrometry data obtained from filter samples corroborated the peak assignments. The size-resolved chemical composition measurements revealed that organosulfate species were mostly detected in submicrometer aerosols and across a range of aerosols from different sources, consistent with secondary reaction products. Detection of organosulfates in a large fraction of negative-ion ambient spectra − ca. 90−95% during ANARChE and ~65% of submicrometer particles in AMIGAS − highlights the ubiquity of organosulfate species in the ambient aerosols of biogenically influenced urban environments

    An attempt to determine variability of RNA/DNA ratios during Dicentrarchus labrax larval development

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    RNA and DNA content of seabass (Dicentrarchus labra.x) larvae were determined from day 10 to day 60 after hatching in an aquaculture facility. Our results show a two-phase modulation of the RNA/DNA ratio throughout seabass larvae development. From day 10 after hatching there is an increase in the RNA/DNA ratio reaching maximal values at day 30 of age. Then, the RNA/DNA ratio decreased reaching minimal values at day 60 after hatching. These results are consistent with a high rate of protein synthesis during the first 30 days of seabass development compared with the rest of the developmental period studied. The results are compared with that of otolith growth carried out for the same species larvaeAPROXIMACIÓ A LA DETERMINACIÓ DE LA VARIABILITAT DE LA RELACIÓ DNA/RNA DURANT EL DESENVOLUPAMENT LARVAL DEL LLOBARRO Dicentrarchus labrax. S'ha determinat el contingut de DNA (àcid desoxiribonucleic) i de RNA (àcid ribonucleic) en larves de llobarro (Dicentrarchus labrax) d'edats compreses entre 10 i 60 dies de vida, procedents d'una planta de cultiu. Els resultats obtinguts mostren dues fases diferenciades de desenvolupament d'aquestes larves, basades en la relaci6 RNA/DNA avaluada. S'observa un augment de la proporci6 de RNNDNA des del dia 10 fins el dia 30 de vida, per a decréixer a continuació, trobant els valors mínims en les larves de 60 dies de vidaPublicado

    Effects of monthly feedback of VFA measured by dual BIA method in Japanese patients with obesity: a randomized controlled study

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    Objective: To investigate the effects of monthly feedback of changes in visceral fat area (VFA) as measured by dual bioelectrical impedance analysis method and the importance of VFA in individuals with obesity. Methods: Thirty‐eight Japanese patients with obesity underwent VFA measurements. The feedback group was given feedback on VFA measurements each month for 4 months. The control group underwent VFA measurements at the beginning and end of the study but was not informed of the results. All the study participants completed eating behaviour and weight efficacy lifestyle questionnaires. Results: Mean age was 53.9 (14.3) years; mean body mass index was 30.6 (4.3) kg m⁻². At the 4‐month follow‐up, there was no significant difference in VFA reduction between the control and feedback groups (−4.4% vs. −3.0%; 95% CI, −3.8 to 5.5). In post‐hoc analysis using the overall group irrespective of allocation, changes of eating style were significantly associated with a reduction in VFA at 4 months (p = 0.034). Conclusions: Monthly feedback on changes in VFA does not reduce VFA. More frequent feedback may be required. In post‐hoc analysis, changes of eating style were associated with a reduction in VFA
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