Каталитическая активность разнометальных комплексов CuII/MnII с этилендиамином в реакции разложения пероксида водорода

Показано, что разнометальные соединения [Cuеn₂][MnCl₄], [Cu(phen)₂Cl]₂ [MnCl₄] и [{Cuen₂}₃Mn(NCS)₆](NCS)₂ являются эффективными катализаторами реакции разложения пероксида водорода. Активность этих соединений во время реакции существенно уменьшается, что объясняется их разложением под действием реакционной среды. Предложена математическая модель процесса, позволяющая рассчитать эффективные константы процессов разложения H₂O₂ и дезактивации катализатора. Особенностью разложения пероксида в присутствии [{Cuen₂}₃Mn(NCS)₆](NCS)₂ является индукционный период, который объясняется наличием тиоционатных групп в составе комплекса. Рассчитаны константы всех стадий процесса, а также энергии активации для температурного интервала 288—303 K.Показано, що різнометальні сполуки [Cuеn₂][MnCl₄], [Cu(phen)₂Cl]₂ [MnCl₄] і [{Cuen₂}₃Mn(NCS)₆](NCS)₂ є ефективними каталізаторами реакції розкладу пероксиду водню. Активність цих сполук впродовж реакції суттєво зменшується, що пояснюється їх розкладом під дією реакційного середовища. Запропоновано математичну модель процесу, що дозволяє обчислити ефективні константи процесів розкладу H₂O₂ і дезактивації каталізатора. Особливістю розкладу пероксиду в присутності [{Cuen₂}₃Mn(NCS)₆](NCS)₂ є індукційний період, що пояснюється наявністю тіоціонатних груп у складі комплексу. Розраховано константи всіх стадій процесу, а також енергії активації для температурного інтервалу 288–303 K.Compounds [Cuеn₂][MnCl₄], [Cu(phen)₂Cl]₂ [MnCl₄] and [{Cuen₂}₃Mn(NCS)₆](NCS)₂ are shown as effective catalysts at reaction of hydrogen peroxide decomposition. Activity of these compounds during the reaction are considerably decreasing, that can be explained by theirs decomposition at reaction medium. Mathematical model allowing to calculate effective constants of H₂O₂ decomposition and catalysts deactivation has been suggested. The peculiarity of H₂O₂ decomposition with [{Cuen₂}₃Mn(NCS)₆](NCS)₂ is induction period, that can be explained by presence of thiocyanate groups at complexes. Constants of all reaction stages and theirs activation energies at temperature range 288—303 K have been calculated

Evaluating the importance of mangroves as fish nurseries in selected warm temperate South African estuaries

The value of mangrove habitats as fish nurseries was assessed by comparing communities of early stage and juvenile fishes between estuaries with and without mangroves. Early stage fishes were sampled using boat-based plankton towing while juveniles were sampled by seine netting. Sampling took place at five sites spaced 1 km apart starting near the estuary mouth in four estuaries along the temperate coastline of the Eastern Cape Province of South Africa. Four estuaries were selected based on shared similarities which included catchment area, estuarine area and shared habitats barring the presence of mangroves which occupied the river margins of two systems. Results revealed that early stage and juvenile fish communities (both marine- and estuary-spawned) were similar between systems with and without mangrove habitats. Differences in fish communities among estuaries were rather attributed to axial salinity gradients associated with greater freshwater input, while season and temperature produced significant variances in fish densities with Generalised Additive Models revealing responses of communities to these variables. A common estuarine-dependent fish, Rhabdosargus holubi (Family Sparidae), was further investigated to determine habitat use, residency and dietary patterns in different mangrove habitats. High habitat residency in this species was revealed during a short-term tagging study using Visible Implant Elastomer tags and long-term isotope analysis in juveniles sampled from two contrasting mangrove habitats. A wider feeding niche was observed in an eelgrass-red mangrove connected habitat when compared with more exposed white mangrove areas. Low dependence on mangrove habitats in temperate estuaries is likely due to their tidally dominated inundation and limited refuge potential due to smaller area coverage by mangroves in temperate estuaries. Relatively lower primary productivity in warm temperate mangrove areas, relative to their tropical counterparts, provides no significant feeding advantage or refuge opportunities relative to other available habitats in these estuaries. Warm temperate estuaries, which are both spatially and temporally highly variable, instead host species which are habitat generalists, able to capitalise on these highly dynamic environments

On the spacing distribution of the Riemann zeros: corrections to the asymptotic result

It has been conjectured that the statistical properties of zeros of the Riemann zeta function near z = 1/2 + \ui E tend, as $E \to \infty$, to the distribution of eigenvalues of large random matrices from the Unitary Ensemble. At finite $E$ numerical results show that the nearest-neighbour spacing distribution presents deviations with respect to the conjectured asymptotic form. We give here arguments indicating that to leading order these deviations are the same as those of unitary random matrices of finite dimension $N_{\rm eff}=\log(E/2\pi)/\sqrt{12 \Lambda}$, where $\Lambda=1.57314 ...$ is a well defined constant.Comment: 9 pages, 3 figure

An eco-physiological investigation of fisheries-induced evolution: comparing the resilience of larvae from exploited and unexploited commercial reef fish populations to projected ocean acidification

It is now accepted that anthropogenic-induced climate change is resulting in unprecedented rates of change to marine environments. Marine organisms are being challenged by rapidly increasing temperatures, acidification, expansion of oxygen dead zones, and higher frequencies and magnitudes of extreme weather events. Exploited fish populations are also undergoing selective harvesting. Certain traits, such as large size, fast growth, and/or bold/active behaviours, are being actively targeted and removed from the population gene pool. This selective removal of individuals may compromise the capacity of fish populations to resist or recover from environmental disturbances and reduce their ability to adapt to a changing environment as many of these traits are heritable. As most marine fishes' embryonic and larval stages represent the period when individuals are most sensitive to environmental disturbances, they are a critical bottleneck to population persistence in the face of exploitation and climate change. This thesis aimed to quantify and compare the metabolic physiology, growth, and development of an exploited and endemic sparid, the roman seabream Chrysoblephus laticeps, during the early larval stages under 1) ocean acidification conditions expected by the year 2100 and 2) from populations experiencing dissimilar rates of exploitation. To quantify and compare the physiology of larvae, adult C. laticeps from an exploited population were captured and field-spawned. Fertilised eggs were placed into either control/present-day conditions (pH = 8.03, pCO2 ≈ 420 μatm) or high-pCO2/hypercapnic treatment conditions (pH = 7.63, pCO2 ≈ 1400 μatm). The metabolic physiology of individual larvae was determined using a novel rolling-regression technique on static respirometry data. Here, estimates of the minimum and maximum oxygen consumption rates (VO2) could be determined with high test-retest reliability. The very early developmental stages (yolk-sac stage) appeared resilient to high pCO2 conditions despite being exposed to treatment conditions throughout the embryonic stage. Preflexion larvae showed sensitivity to treatment conditions by exhibiting reduced metabolic and growth rates, consistent with metabolic depression, associated with environmental stress. However, by the onset of flexion, which coincides with gill development, acid-base regulation, and muscle differentiation, metabolic and growth rates of treatment larvae were significantly greater than that of controls. This suggests that acid-base regulation imposes a high cost to maintain internal pH homeostasis. Importantly, these elevated metabolic costs were likely mediated through increased feeding rates in experimental conditions where food was ad libitum. In natural conditions, where food availability may be varied, high pCO2 conditions could be associated with higher mortality rates. Based on evidence that protected/unexploited populations are more genetically diverse and are composed of individuals representing a greater range of metabolic phenotypes, offspring were collected from a protected population experiencing otherwise similar environmental conditions to the exploited population. Metabolic rates of control larvae were generally similar to those of the exploited population. However, minimum rates of VO2 were typically higher for larvae from the protected population at comparable life stages. Preflexion treatment larvae from the protected population did not appear to undergo a period of reduced metabolism or growth compared to their control counterparts. While metabolic rates at the onset of flexion were significantly higher for treatment larvae, this was not associated with growth differences. Growth over-compensation following periods of growth depression is often associated with deleterious effects, such as organ damage and body or developmental malformations. This suggests somewhat improved resilience to ocean acidification conditions. This thesis found evidence that larval C. laticeps are sensitive to ocean acidification conditions expected by 2100. When this stressor is combined with increasing thermal variability, changing current coastal regimes, and heterogeneous food availability, also expected to occur by 2100, ocean acidification may compromise the population persistence of this species. However, an energetics approach to stress-tolerance suggests that larvae from the protected population may inherently show greater resilience to climate change-related environmental stressors. Evidence that exploitation affects the resilience of fish larvae to climate change highlights the need for an evolutionary approach to fisheries management and the importance of spatial protection in maintaining larger and more resilient populations while providing the raw material essential for adaptation.Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 202

Tensor Products of Random Unitary Matrices

Tensor products of M random unitary matrices of size N from the circular unitary ensemble are investigated. We show that the spectral statistics of the tensor product of random matrices becomes Poissonian if M=2, N become large or M become large and N=2.Comment: 23 pages, 2 figure

El protocolo familiar como herramienta estratégica para la subsistencia de las empresas familiares: un caso de estudio

"La mayoría de las empresas familiares, no obstante ser rentables, no pasan a la segunda generación. Esta problemática no es local o regional, sino global. Muchos estudios hablan de las causas de dicho problema; falta de profesionalización, falta de reglas entre familia y empresa y otros factores de igual manera relevantes. Frente a esta situación el enorme mundo de la administración y los negocios ha venido paulatinamente, creando una figura a manera de herramienta estratégica, que contrarresta dicha problemática: el Protocolo familiar. Así, el objetivo de este trabajo es brindar a la empresa familiar X un protocolo familiar con el fin de que perdure en el tiempo, pasando de una generación a otra. Para ello, se ha recurrido a un estudio de caso que aportará los elementos necesarios para analizar la problemática y llegar a algunas conclusiones significativas. Con un enfoque cualitativo basado en una entrevista semi guiada se trabajó un caso con la empresa familiar X. Los resultados obtenidos como resultado de esta investigación permiten afirmar que el Protocolo familiar contribuye de manera notable a que las empresas familiares subsistan al pasar de una generación a otra"

Manuel de Elías: Hermenéutica de su conciencia ceadora y experiencia formativa

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Formación de Profesorado y Educación. Departamento de Didáctica y Teoría de la Educación. Fecha de lectura: 22-09-2017La investigación estudia cuestiones específicas del proceso creativo del reconocido compositor y director de orquesta Manuel de Elías. Sus objetivos son tres: el primero es profundizar en la comprensión del proceso creativo de Manuel de Elías. El segundo es indagar, desprender y sistematizar implicaciones de la creatividad del autor para la formación de otros compositores. El tercero es validar y transferir implicaciones formativas para el proceso creativo de compositores concretos. La metodología de la investigación responde a un estudio de caso, de corte biográfico, seleccionado por su reconocido potencial creativo. El enfoque epistémico es hermenéutico, centrado en la experiencia estética, intuitiva y anímica aplicada a la composición musical del autor y recorrida, desde su ser-en-el-mundo, hasta su exposición e interpretación de estados de conciencia creadores en el proceso de composición de su obra. Se trabajará con una selección de compositores latinoamericanos –que actuarán a la vez como expertos y participantes del estudio-, que valorarán y algunos validarán la bondad de las implicaciones de las observaciones hechas en Manuel de Elías y la transferibilidad formativa, en el campo de su formación mediante creatividad para la composición musical. Las conclusiones apuntan a una riqueza extraordinaria del proceso creativo en la composición musical de Manuel de Elías, hasta cierto punto comprensible, objetivable y transferible a la formación mediante creatividad de otros compositores, específicamente relacionada con el enriquecimiento de la experiencia estética. Se concluye con que la experiencia del universo anímico y de invención de Manuel de Elías, desarrollada en torno a su proceso creativo compositor, puede ser un referente pedagógico facilitador de una identificación afectiva importante para la formación de otros compositores

Remittances and votes: Emigrant political participation in Mexico.

Few recent studies have shown how Mexico, like many other Latin American countries at the beginning of this century, has adopted new policies and programmes in order to maintain and (re)build economic, social and cultural bonds with its migrant communities in the US, who represent about 15 percent of Mexico's population. Less research has been conducted on the constitutional reforms and electoral laws that allow Mexicans abroad to participate politically in their home country's domestic affairs from afar. Employing a transnationalist approach to international migration and democratization studies, this thesis is the first major study of the politics of Mexican emigration to the US and the impact of migrants' electoral participation in their home country's affairs presented in political and institutional terms. The main question is how and with what consequences did the Mexican state extend formal political membership to its emigrant population both at the national and subnational level. Using a combination of quantitative and qualitative methods, this thesis shows that the implementation of emigrants' political rights in Mexico has resulted from cross-border coalition formations between US-based political migrant groups and domestic non-PRI political parties (mainly the centre-left PRD) in a context of democratization and decentralization unfolding in Mexico, as well as the country's insertion in the global economy. In turn, although only a small number of Mexican migrants have taken advantage of these opportunities for cross-border political action to date, the opening up of the Mexican political system creates new challenges to the incipient democratic practice. For instance, the growing influence of migrants and migrant organisations in domestic politics, the complexities of representing and being accountable to constituencies abroad and to a limited extent, the transformation of traditional political structures, especially in communities with high levels of emigration