4D Spin Glasses in Magnetic Field Have a Mean Field like Phase

By using numerical simulations we show that the 4D $J=\pm 1$ Edwards Anderson spin glass in magnetic field undergoes a mean field like phase transition. We use a dynamical approach: we simulate large lattices (of volume $V$) and work out the behavior of the system in limit where both $t$ and $V$ go to infinity, but where the limit $V \to \infty$ is taken first. By showing that the dynamic overlap $q$ converges to a value smaller than the static one we exhibit replica symmetry breaking. The critical exponents are compatible with the ones obtained by mean field computations.Comment: Physrev format, 5 ps figures include

Temporal variations of zooplankton biomass in the Ligurian Sea inferred from long time series of ADCP data

Abstract. Three years of 300 kHz acoustic doppler current profiler data collected in the central Ligurian Sea are analysed to investigate the variability of the zooplankton biomass and the diel vertical migration in the upper thermocline. After a pre-processing phase aimed at avoiding the slant range attenuation, hourly volume backscattering strength time series are obtained. Despite the lack of concurrent net samples collection, different migration patterns are identified and their temporal variability examined by means of time–frequency analysis. The effect of changes in the environmental condition is also investigated. The highest zooplankton biomasses are observed in April–May just after the peak of surface primary production in March–April. The main migration pattern found here points to a "nocturnal" migration, with zooplankton organisms occurring deeper in the water column during the day and shallower at night. Also, twilight migration is highlighted during this study. The largest migrations are recorded in November–December, corresponding to lowest backscattering strength values and they are likely attributable to larger and more active organisms (i.e. euphausiids and mesopelagic fish). The results suggest further applications of the available historical acoustic doppler current profiler time series

Genetic programs driving oncogenic transformation: Lessons from in vitro models

Cancer complexity relies on the intracellular pleiotropy of oncogenes/tumor suppressors and in the strong interplay between tumors and micro- and macro-environments. Here we followed a reductionist approach, by analyzing the transcriptional adaptations induced by three oncogenes (RAS, MYC, and HDAC4) in an isogenic transformation process. Common pathways, in place of common genes became dysregulated. From our analysis it emerges that, during the process of transformation, tumor cells cultured in vitro prime some signaling pathways suitable for coping with the blood supply restriction, metabolic adaptations, infiltration of immune cells, and for acquiring the morphological plasticity needed during the metastatic phase. Finally, we identified two signatures of genes commonly regulated by the three oncogenes that successfully predict the outcome of patients affected by different cancer types. These results emphasize that, in spite of the heterogeneous mutational burden among different cancers and even within the same tumor, some common hubs do exist. Their location, at the intersection of the various signaling pathways, makes a therapeutic approach exploitable

Historic Churches and Their Hygrothermal Environment: A Review of Criteria Related to Building Fabric, Artefacts, Artwork and Occupants

Regarded as important cultural heritage, historic churches have been utilised over hundreds of years for worship and community benefit. Simple on/off space heating systems are installed in many churches to increase human comfort. However, the conservation of the important historic artefacts and artwork contained within may not have been fully considered. This review attempts to appraise the standards in place for artefacts and artwork. A consensus of 15–25 °C and 40–65% relative humidity is established as safe from the standards reviewed. Consideration is given to the environment within the church to understand if such exacting conditions can be met. The review finds that the conservation and preservation of artefacts and buildings are aligned goals, although striving to meet specified target ranges for artefact types is not fully compatible with historic churches. The stability of the internal environment is clearly an important factor in conservation and benefits human comfort expectations. Churches may contain microclimates throughout the building, complicating the use of target ranges for artefacts, artwork and comfort. The findings of this study can assist historic churches in managing the change, alteration or installation of heating systems

Herramientas hidrogeoquímicas aplicadas a la evaluación del acuífero de Trenque Lauquen, provincia de Buenos Aires, Argentina

La ciudad de Trenque Lauquen en la provincia de Buenos Aires, Argentina se abastece exclusivamente del recurso hídrico subterráneo. El objetivo del trabajo es analizar la evolución temporal en la calidad fisicoquímica del agua, teniendo en cuenta las características hidrogeológicas y los procesos con la matriz sólida. La metodología consistió en la valoración y síntesis de la información geológica, geofísica, hidrogeológica e hidroquímica y la modelación de procesos hidrogeoquímicos. El agua del acuífero incrementa su salinidad con la profundidad de explotación y evoluciona hacia una disolución de yeso y precipitación de calcita, con el consiguiente incremento del contenido de sulfatos y de dureza. Se consideran apropiadas las medidas de gestión en los últimos años, que condujeron a realizar perforaciones más someras y con menor caudal de extracción, lo que ha permitido que la tendencia creciente a la salinización haya disminuido su tasa de evolución, mejorando la calidad del agua subterránea.The city of Trenque Lauquen in the Buenos Aires Province, Argentina, gets water supply ex-clusively from groundwater resources. The goal of this study is to analyze time trends related to water quality, taking into account hydrogeological characteristics and processes with the solid matrix. The methodology consisted in the assessment and summary of geological, geophysical, hydrogeological and hydrochemical in-formation, and hydrogeochemical modelling. Groundwater salinity increases with the depth of exploitation and evolves into a gypsum dissolution and calcite precipitation, increasing sulphate content and hardness. Water management measures in recent years, based on shallow wells and lower extraction volumes became appropriate since the rate of salinization has decreased improving groundwater quality

Temperature Chaos, Rejuvenation and Memory in Migdal-Kadanoff Spin Glasses

We use simulations within the Migdal-Kadanoff real space renormalization approach to probe the scales relevant for rejuvenation and memory in spin glasses. One of the central questions concerns the role of temperature chaos. First we investigate scaling laws of equilibrium temperature chaos, finding super-exponential decay of correlations but no chaos for the total free energy. Then we perform out of equilibrium simulations that follow experimental protocols. We find that: (1) rejuvenation arises at a length scale smaller than the ``overlap length'' l(T,T'); (2) memory survives even if equilibration goes out to length scales much larger than l(T,T').Comment: 4 pages, 4 figures, added references, slightly changed content, modified Fig.

The Phenomenology of Strings and Clusters in the 3-d Ising Model

We examine the geometrical and topological properties of surfaces surrounding clusters in the 3--$d$ Ising model. For geometrical clusters at the percolation temperature and Fortuin--Kasteleyn clusters at $T_c$, the number of surfaces of genus $g$ and area $A$ behaves as $A^{x(g)}e^{-\mu(g)A}$, with $x$ approximately linear in $g$ and $\mu$ constant. We observe that cross--sections of spin domain boundaries at $T_c$ decompose into a distribution $N(l)$ of loops of length $l$ that scales as $l^{-\tau}$ with $\tau \sim 2.2$. We address the prospects for a string--theoretic description of cluster boundaries. (To appear in proceedings for the Cargese Workshop on "String Theory, Conformal Models and Topological Field Theories", May 1993)Comment: 20 pages followed by 15 uuencoded ps figures, latex, SU-HEP-4241-563, PAR-LPTHE 93/5