Analysis of actinometric measurements under allsky and cloud-free conditions in Cáceres (Spain) for the period 1913–1920

Early daily actinometric and cloud cover data from C aceres (SW of Spain) were recovered for the period 1913–1920. The task of retrieving and digitising early actinometric data series turn out highly required due to the lack of solar radiation data throughout the first half of twentieth century. Firstly, the Arago actinometer and the procedure employed to record the actinometric data were described in detail. Additionally, in spite of being a short series, trends from recovered actinometric data were analysed. A negative trend of (0.16 ± 0.03) C/year was obtained for all-sky conditions, reaching a marked value of (0.26 ± 0.04) C/year when cloud-free days were selected in the analysis. Both trends were statistically significant at the 95% confidence level. The Katmai eruption in June 1912 likely caused anomalous low actinometric records in 1913 and 1914. These results suggest a decrease of solar radiation in C aceres during the second decade of the twentieth century which is in accordance with the final stage of the long-term negative trend in solar radiation data observed at several European sites from late nineteenth century to the beginning of the twentieth century (‘early dimming’).This work was partly funded by FEDER-Junta de Extremadura [Research Group Grant GR15137 and project IB16127] and from the Ministerio de Econom ıa y Competitividad of the Spanish Government [CGL2017- 87917-P]

Spherically symmetric dissipative anisotropic fluids: A general study

The full set of equations governing the evolution of self--gravitating spherically symmetric dissipative fluids with anisotropic stresses is deployed and used to carry out a general study on the behaviour of such systems, in the context of general relativity. Emphasis is given to the link between the Weyl tensor, the shear tensor, the anisotropy of the pressure and the density inhomogeneity. In particular we provide the general, necessary and sufficient, condition for the vanishing of the spatial gradients of energy density, which in turn suggests a possible definition of a gravitational arrow of time. Some solutions are also exhibited to illustrate the discussion.Comment: 28 pages Latex. To appear in Phys.Rev.

Flexibilidad energética en barrio de edificios residenciales mediante la activación de la masa termica. Resultados experimentales en un entorno semivirtual

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: En los próximos años los edificios se convertirán en productores y consumidores de energía al mismo tiempo. Por esta razón, la gestión de la demanda a nivel de edificio y a nivel de barrio a través de un agregador independiente requerirá de sistemas de control inteligentes con el objetivo de optimizar y gestionar dos aspectos: maximizar el uso de energía renovable local y usar la energía de la red en el momento más oportuno. El presente estudio se enfoca en los resultados de un sistema de algoritmos de optimización multi-nivel testeados en tiempo real. El experimento desarrollado reproduce, en dos laboratorios físicamente alejados 100 km, el comportamiento de dos edificios de un mismo barrio mediante un sistema semi-virtual donde unos modelos del edificio determinan su demanda energética emulandola en los laboratorios haciendo actuar al equipamiento físico en condiciones reales de trabajo. Los resultados muestran que la gestión inteligente de la masa térmica del edificio con los algoritmos de optimización puede aportar los mismos beneficios que instalar una batería eléctrica actuando con algoritmos inteligentes o de autoconsumo.ABSTRACT: In the coming years, buildings will become energy producers and consumers at the same time. To optimize the system operation, smart control algorithms shall manage the energy demand of an individual building and of entire districts of buildings. The algorithms goals shall maximize the use of the renewable energy produced on-site and using the energy from the electric grid at the most appropriate time. The current study focus on the results of a multilevel optimization system tested in real-time. The experiment performed reproduces, in two laboratories 100 km away, the behavior of two buildings of similar characteristics hypothetically located in the same district. This is done with energy building models which allows emulating their energy demands connected to real laboratory equipment (heat pumps, PV, batteries and management and control systems). Results of the experiments show that the smart activation of the building’s thermal mass can bring similar benefits than installing an electric battery that acts following smart or self-consumption management strategies.info:eu-repo/semantics/publishedVersio

On surface tension for compact stars

In an earlier treatment it was demonstrated that general relativity gives higher values of surface tension in strange stars with quark matter than neutron stars.We generate the modified Tolman-Oppenheimer-Volkoff equation to incorporate anisotropic matter and use this to show that pressure anisotropy provides for a wide range of behaviour in the surface tension than is the case with isotropic pressures. In particular it is possible that anisotropy drastically decreases the value of the surface tension.Comment: 8 pages, To appear in J. Astrophys. Astro

Sociobiological Control of Plasmid copy number

Background:
All known mechanisms and genes responsible for the regulation of plasmid replication lie with the plasmid rather than the chromosome. It is possible therefore that there can be copy-up mutants. Copy-up mutants will have within host selective advantage. This would eventually result into instability of bacteria-plasmid association. In spite of this possibility low copy number plasmids appear to exist stably in host populations. We examined this paradox using a computer simulation model.

Model:
Our multilevel selection model assumes a wild type with tightly regulated replication to ensure low copy number. A mutant with slightly relaxed replication regulation can act as a “cheater” or “selfish” plasmid and can enjoy a greater within-host-fitness. However the host of a cheater plasmid has to pay a greater cost. As a result, in host level competition, host cell with low copy number plasmid has a greater fitness. Furthermore, another mutant that has lost the genes required for conjugation was introduced in the model. The non-conjugal mutant was assumed to undergo conjugal transfer in the presence of another conjugal plasmid in the host cell.

Results:
The simulatons showed that if the cost of carrying a plasmid was low, the copy-up mutant could drive the wild type to extinction or very low frequencies. Consequently, another mutant with a higher copy number could invade the first invader. This process could result into an increasing copy number. However above a certain copy number within-host selection was overcompensated by host level selection leading to a rock-paper-scissor (RPS) like situation. The RPS situation allowed the coexistence of high and low copy number plasmids. The non-conjugal “hypercheaters” could further arrest the copy numbers to a substantially lower level.

Conclusions:
These sociobiological interactions might explain the stability of copy numbers better than molecular mechanisms of replication regulation alone

Policy Challenges for the Development of Energy Flexibility Services

European energy policies call for an increased share of renewable energy sources and a more active role of the energy consumer. This is facilitated by, amongst others, buildings becoming energy flexible hubs, supporting smart energy grids with demand response strategies. While there is abundant technical research in this field, the related business and policy development is less well documented. This research scopes existing policy programmes and identifies opportunities and barriers to business development supporting energy flexible buildings. Using examples from seven European countries, this work reviews influencing niche management factors such as existing policy instruments, business development cases and identified stakeholder concerns, using literature research, narrative analysis and stakeholder research. National policy pathways show many differences but confirm that European buildings might become active players in the energy market, by providing energy storage, demand response and/or shifts in the use of energy sources. Slow sustained business development for energy flexibility services was mainly identified in the retail industry, and for energy service companies and aggregators. The direct involvement of end users in energy flexible buildings is still difficult. Stakeholders call for policy improvement, especially concerning the development of flexible energy tariffs, supporting incentives, awareness raising and more stakeholder-targeted business development

Análisis de medidas actinométricas registradas en el periodo 1913-1923 en Cáceres (España)

Ponencia presentada en: XI Congreso de la Asociación Española de Climatología celebrado en Cartagena entre el 17 y el 19 de octubre de 2018.[ES]El análisis de las tendencias de los datos actinométricos registrados en Cáceres en el periodo 1913-1920 muestra un decrecimiento significativo con pendiente (-0.16 ± 0.03) ºC/año. Además, se ha realizado el análisis de las tendencias eliminando los factores externos que pueden alterarlo (erupción del volcán Katmai en 1912) mostrando un decrecimiento significativo también, pero con pendiente mayor (-0.28 ± 0.04) °C/año. También, se han analizado las tendencias en ambos periodos (1913-1920 y 1915-1920) para las distintas estaciones del año y, además, separando las medidas actinométricas por categorías de nubes al disponer de datos de cubierta nubosa. Estos resultados sugieren un decrecimiento de la radiación solar en Cáceres durante la segunda década del siglo XX en concordancia con el descenso radiativo en superficie observado en Europa entre finales del siglo XIX y principios del XX early dimming”).[EN]The analysis of the trends of the actinometric data recorded in Cáceres in the period 1913-1920 shows a significant decrease with slope (-0.16 ± 0.03) °C/year. In addition, the analysis of the trends has been done without the external factors that can modify it (the Katmai eruption in 1912) showing a significant decrease as well, but with a greater slope of (-0.28 ± 0.04) °C/year. Also, trends have been analyzed in both periods (1913-1920 and 1915-1920) for the different seasons of the year and, in addition, separating the actinometric measurements by cloud categories because cloud cover data were recorded as well in the same period. These results suggest a decrease in solar radiation in Cáceres during the second decade of the 20th century in accordance with the radiative decrease at surface observed in Europe between the end of the 19th century and the beginning of the 20th ("early dimming").Este trabajo ha sido parcialmente financiado por FEDER-Junta de Extremadura (GR15137 y IB16127) y por el Ministerio de Economía y Competitividad del Gobierno de España (AYA2014-57556-P y CGL2017-87917-P)

Proposed atomic cascade experimental test of symmetric local hidden-variables theories

The proposal is made of replacing the usual auxiliary assumptions needed for the derivation of testable Bell inequalities by an assumption resting only on symmetry considerations. It is shown that reliable atomic cascade tests of symmetric local hidden-variables theories should combine high statistics, cascades of type 0→1→0, and calcite polarizers. The three conditions have been achieved in experiments already performed, but never before simultaneously

Stable Maintenance of Multiple Plasmids in E. coli Using a Single Selective Marker

Plasmid-based genetic systems in Escherichia coli are a staple of synthetic biology. However, the use of plasmids imposes limitations on the size of synthetic gene circuits and the ease with which they can be placed into bacterial hosts. For instance, unique selective markers must be used for each plasmid to ensure their maintenance in the host. These selective markers are most often genes encoding resistance to antibiotics such as ampicillin or kanamycin. However, the simultaneous use of multiple antibiotics to retain different plasmids can place undue stress on the host and increase the cost of growth media. To address this problem, we have developed a method for stably transforming three different plasmids in E. coli using a single antibiotic selective marker. To do this, we first examined two different systems with which two plasmids may be maintained. These systems make use of either T7 RNA polymerase-specific regulation of the resistance gene or split antibiotic resistance enzymes encoded on separate plasmids. Finally, we combined the two methods to create a system with which three plasmids can be transformed and stably maintained using a single selective marker. This work shows that large-scale plasmid-based synthetic gene circuits need not be limited by the use of multiple antibiotic resistance genes

Risk of malignant lymphoma associated with human herpesvirus-8: a case–control study in Spain

No overall increased risk of lymphoma associated with antibodies to human herpesvirus-8 was found in 526 lymphomas and 599 controls (odds ratio (OR)=1.04, 95% confidence interval (CI)=0.62-1.75); significant increases were noted for 19 lymphoplasmacytic lymphomas (OR=4.47, 95% CI=1.34-14.85) and nine low-grade lymphoma/lymphoma B-cell NOS (OR=5.82, 95% CI=1.07-31.73)