Non exponential relaxation in fully frustrated models

We study the dynamical properties of the fully frustrated Ising model. Due to the absence of disorder the model, contrary to spin glass, does not exhibit any Griffiths phase, which has been associated to non-exponential relaxation dynamics. Nevertheless we find numerically that the model exhibits a stretched exponential behavior below a temperature T_p corresponding to the percolation transition of the Kasteleyn-Fortuin clusters. We have also found that the critical behavior of this clusters for a fully frustrated q-state spin model at the percolation threshold is strongly affected by frustration. In fact while in absence of frustration the q=1 limit gives random percolation, in presence of frustration the critical behavior is in the same universality class of the ferromagnetic q=1/2-state Potts model.Comment: 7 pages, RevTeX, 11 figs, to appear on Physical Review

Experiencias y comprensiones sobre violencias contra mujeres jóvenes : relatos de mujeres entre 18 y 29 años en la ciudad de Bogotá

La violencia contra mujeres jóvenes es una problemática social que ha incrementado en los últimos años, ya que las mujeres entre los 18 y 29 años son las víctimas más frecuentes de violencia basada en género. Para el año 2013, en Colombia el más alto número de mujeres asesinadas se encontraban entre los 15 y 29 años. Sin embargo, es notable el bajo índice de denuncia de hechos de violencia contra mujeres en esta etapa del ciclo vital. Por tanto, esta investigación indaga sobre experiencias y comprensiones relativas a las violencias contra las mujeres relatadas por mujeres jóvenes entre 18 y 29 años en la ciudad de Bogotá. Para el análisis de los relatos se acude a la perspectiva de género y a categorías como subjetividad femenina, violencia contra mujeres y ámbito público-privado. Se utiliza una metodología con enfoque cualitativo y se diseña un cuestionario con 24 preguntas que fue aplicado a 40 mujeres de todos los estratos socioeconómicos, divididas en dos rangos de edades: entre 18 y 23 años, y entre 24 y 29 años, posteriormente, se realizó un grupo focal con seis mujeres. Se identifica que los tipos de violencia psicológica, sexual y física son las que más afectan a las mujeres jóvenes. Igualmente se hace evidente que, si bien las jóvenes reconocen y son conscientes sobre situaciones y tipos de violencias en lugares públicos y privados en los que se sienten o están efectivamente en riesgo, la persistencia de roles estereotipados de género coexisten con discursos contradictorios de contenido relativamente emancipatorio respecto a condiciones históricas y culturales que configuran sus subjetividades, lo cual incide de manera negativa respecto a prácticas de autoprotección y de denuncia.Violence against young women is a social issue that has increased in the last few years, women between the ages of 18 and 29 are the most frequent victims of gender-based violence. In 2013, the highest number of murdered women in Colombia was between the ages of 15 and 29. However the report rate of these violent crimes against women at this stage of their life cycle is notably low. Therefore, this investigation is about experiences related to violence against women, described by young women between the ages of 18 and 29 in the city of Bogota. For the analysis of the stories, we resort to gender perspective and categories like feminine subjectivity, violence against women, and the public-private sector. We opted for a method with a qualitative focus and designed a questionnaire with 24 questions that was presented to 40 women of all the socioeconomic levels, divided in two age groups: between 18 and 23, and between 24 and 29, afterwards we formed a focal group of six women. We identified that the types of violence that most affects young women are psychological, sexual, and physical. Likewise, it s evident that if young women recognize and are conscious about situations and types of violence in public and private places in which they feel or are in fact at risk, the persistence of stereotypical gender roles coexist with contradictory speeches of relatively emancipatory content regarding historical and cultural conditions that configure their subjectivity, which influences them in a negative way regarding practices of autoprotection and reporting of crimes.Psicólogo (a)Pregrad

Phase Separation and the Low-Field Bulk Magnetic Properties of Pr0.7Ca0.3MnO3

We present a detailed magnetic study of the perovskite manganite Pr0.7Ca0.3MnO3 at low temperatures including magnetization and a.c. susceptibility measurements. The data appear to exclude a conventional spin glass phase at low fields, suggesting instead the presence of correlated ferromagnetic clusters embedded in a charge-ordered matrix. We examine the growth of the ferromagnetic clusters with increasing magnetic field as they expand to occupy almost the entire sample at H ~ 0.5 T. Since this is well below the field required to induce a metallic state, our results point to the existence of a field-induced ferromagnetic insulating state in this material.Comment: 15 pages with figures, submitted to Physical Review

Integration Preferences of Wildtype AAV-2 for Consensus Rep-Binding Sites at Numerous Loci in the Human Genome

Adeno-associated virus type 2 (AAV) is known to establish latency by preferential integration in human chromosome 19q13.42. The AAV non-structural protein Rep appears to target a site called AAVS1 by simultaneously binding to Rep-binding sites (RBS) present on the AAV genome and within AAVS1. In the absence of Rep, as is the case with AAV vectors, chromosomal integration is rare and random. For a genome-wide survey of wildtype AAV integration a linker-selection-mediated (LSM)-PCR strategy was designed to retrieve AAV-chromosomal junctions. DNA sequence determination revealed wildtype AAV integration sites scattered over the entire human genome. The bioinformatic analysis of these integration sites compared to those of rep-deficient AAV vectors revealed a highly significant overrepresentation of integration events near to consensus RBS. Integration hotspots included AAVS1 with 10% of total events. Novel hotspots near consensus RBS were identified on chromosome 5p13.3 denoted AAVS2 and on chromsome 3p24.3 denoted AAVS3. AAVS2 displayed seven independent junctions clustered within only 14 bp of a consensus RBS which proved to bind Rep in vitro similar to the RBS in AAVS3. Expression of Rep in the presence of rep-deficient AAV vectors shifted targeting preferences from random integration back to the neighbourhood of consensus RBS at hotspots and numerous additional sites in the human genome. In summary, targeted AAV integration is not as specific for AAVS1 as previously assumed. Rather, Rep targets AAV to integrate into open chromatin regions in the reach of various, consensus RBS homologues in the human genome

Volatile organic compounds (VOCs) in photochemically aged air from the eastern and western Mediterranean

During the summertime CYPHEX campaign (CYprus PHotochemical EXperiment 2014) in the eastern Mediterranean, multiple volatile organic compounds (VOCs) were measured from a 650 m hilltop site in western Cyprus (34° 57′ N/32° 23′ E). Periodic shifts in the northerly Etesian winds resulted in the site being alternately impacted by photochemically processed emissions from western (Spain, France, Italy) and eastern (Turkey, Greece) Europe. Furthermore, the site was situated within the residual layer/free troposphere during some nights which were characterized by high ozone and low relative humidity levels. In this study we examine the temporal variation of VOCs at the site. The sparse Mediterranean scrub vegetation generated diel cycles in the reactive biogenic hydrocarbon isoprene, from very low values at night to a diurnal median level of 80–100 pptv. In contrast, the oxygenated volatile organic compounds (OVOCs) methanol and acetone exhibited weak diel cycles and were approximately an order of magnitude higher in mixing ratio (ca. 2.5–3 ppbv median level by day, range: ca. 1–8 ppbv) than the locally emitted isoprene and aromatic compounds such as benzene and toluene. Acetic acid was present at mixing ratios between 0.05 and 4 ppbv with a median level of ca. 1.2 ppbv during the daytime. When data points directly affected by the residual layer/free troposphere were excluded, the acid followed a pronounced diel cycle, which was influenced by various local effects including photochemical production and loss, direct emission, dry deposition and scavenging from advecting air in fog banks. The Lagrangian model FLEXPART was used to determine transport patterns and photochemical processing times (between 12 h and several days) of air masses originating from eastern and western Europe. Ozone and many OVOC levels were  ∼  20 and  ∼  30–60 % higher, respectively, in air arriving from the east. Using the FLEXPART calculated transport time, the contribution of photochemical processing, sea surface contact and dilution was estimated. Methanol and acetone decreased with residence time in the marine boundary layer (MBL) with loss rate constants of 0.74 and 0.53 day−1 from eastern Europe and 0.70 and 0.34 day−1 from western Europe, respectively. Simulations using the EMAC model underestimate these loss rates. The missing sink in the calculation is most probably an oceanic uptake enhanced by microbial consumption of methanol and acetone, although the temporal and spatial variability in the source strength on the continents might play a role as well. Correlations between acetone and methanol were weaker in western air masses (r2  =  0.68), but were stronger in air masses measured after the shorter transport time from the east (r2  =  0.73)

Targeted Chromosomal Insertion of Large DNA into the Human Genome by a Fiber-Modified High-Capacity Adenovirus-Based Vector System

A prominent goal in gene therapy research concerns the development of gene transfer vehicles that can integrate exogenous DNA at specific chromosomal loci to prevent insertional oncogenesis and provide for long-term transgene expression. Adenovirus (Ad) vectors arguably represent the most efficient delivery systems of episomal DNA into eukaryotic cell nuclei. The most advanced recombinant Ads lack all adenoviral genes. This renders these so-called high-capacity (hc) Ad vectors less cytotoxic/immunogenic than those only deleted in early regions and creates space for the insertion of large/multiple transgenes. The versatility of hcAd vectors is been increased by capsid modifications to alter their tropism and by the incorporation into their genomes of sequences promoting chromosomal insertion of exogenous DNA. Adeno-associated virus (AAV) can insert its genome into a specific human locus designated AAVS1. Trans- and cis-acting elements needed for this reaction are the AAV Rep78/68 proteins and Rep78/68-binding sequences, respectively. Here, we describe the generation, characterization and testing of fiber-modified dual hcAd/AAV hybrid vectors (dHVs) containing both these elements. Due to the inhibitory effects of Rep78/68 on Ad-dependent DNA replication, we deployed a recombinase-inducible gene switch to repress Rep68 synthesis during vector rescue and propagation. Flow cytometric analyses revealed that rep68-positive dHVs can be produced similarly well as rep68-negative control vectors. Western blot experiments and immunofluorescence microscopy analyses demonstrated transfer of recombinase-dependent rep68 genes into target cells. Studies in HeLa cells and in the dystrophin-deficient myoblasts from a Duchenne muscular dystrophy (DMD) patient showed that induction of Rep68 synthesis in cells transduced with fiber-modified and rep68-positive dHVs leads to increased stable transduction levels and AAVS1-targeted integration of vector DNA. These results warrant further investigation especially considering the paucity of vector systems allowing permanent phenotypic correction of patient-own cell types with large DNA (e.g. recombinant full-length DMD genes)

Multi-Parametric Analysis and Modeling of Relationships between Mitochondrial Morphology and Apoptosis

Mitochondria exist as a network of interconnected organelles undergoing constant fission and fusion. Current approaches to study mitochondrial morphology are limited by low data sampling coupled with manual identification and classification of complex morphological phenotypes. Here we propose an integrated mechanistic and data-driven modeling approach to analyze heterogeneous, quantified datasets and infer relations between mitochondrial morphology and apoptotic events. We initially performed high-content, multi-parametric measurements of mitochondrial morphological, apoptotic, and energetic states by high-resolution imaging of human breast carcinoma MCF-7 cells. Subsequently, decision tree-based analysis was used to automatically classify networked, fragmented, and swollen mitochondrial subpopulations, at the single-cell level and within cell populations. Our results revealed subtle but significant differences in morphology class distributions in response to various apoptotic stimuli. Furthermore, key mitochondrial functional parameters including mitochondrial membrane potential and Bax activation, were measured under matched conditions. Data-driven fuzzy logic modeling was used to explore the non-linear relationships between mitochondrial morphology and apoptotic signaling, combining morphological and functional data as a single model. Modeling results are in accordance with previous studies, where Bax regulates mitochondrial fragmentation, and mitochondrial morphology influences mitochondrial membrane potential. In summary, we established and validated a platform for mitochondrial morphological and functional analysis that can be readily extended with additional datasets. We further discuss the benefits of a flexible systematic approach for elucidating specific and general relationships between mitochondrial morphology and apoptosis

Oxidation processes in the eastern Mediterranean atmosphere: evidence from the modelling of HOx measurements over Cyprus

The Mediterranean is a climatically sensitive region located at the crossroads of air masses from three continents: Europe, Africa, and Asia. The chemical processing of air masses over this region has implications not only for the air quality but also for the long-range transport of air pollution. To obtain a comprehensive understanding of oxidation processes over the Mediterranean, atmospheric concentrations of the hydroxyl radical (OH) and the hydroperoxyl radical (HO2) were measured during an intensive field campaign (CYprus PHotochemistry EXperiment, CYPHEX-2014) in the northwest of Cyprus in the summer of 2014. Very low local anthropogenic and biogenic emissions around the measurement location provided a vantage point to study the contrasts in atmospheric oxidation pathways under highly processed marine air masses and those influenced by relatively fresh emissions from mainland Europe. The CYPHEX measurements were used to evaluate OH and HO2 simulations using a photochemical box model (CAABA/MECCA) constrained with CYPHEX observations of O3, CO, NOx, hydrocarbons, peroxides, and other major HOx (OH+HO2) sources and sinks in a low-NOx environment (<100pptv of NO). The model simulations for OH agreed to within 10% with in situ OH observations. Model simulations for HO2 agreed to within 17% of the in situ observations. However, the model strongly under-predicted HO2 at high terpene concentrations, this under-prediction reaching up to 38% at the highest terpene levels. Different schemes to improve the agreement between observed and modelled HO2, including changing the rate coefficients for the reactions of terpene-generated peroxy radicals (RO2) with NO and HO2 as well as the autoxidation of terpene-generated RO2 species, are explored in this work. The main source of OH in Cyprus was its primary production from O3 photolysis during the day and HONO photolysis during early morning. Recycling contributed about one-third of the total OH production, and the maximum recycling efficiency was about 0.7. CO, which was the largest OH sink, was also the largest HO2 source. The lowest HOx production and losses occurred when the air masses had higher residence time over the oceans