4,255 research outputs found
Exactly solvable mixed-spin Ising-Heisenberg diamond chain with the biquadratic interactions and single-ion anisotropy
An exactly solvable variant of mixed spin-(1/2,1) Ising-Heisenberg diamond
chain is considered. Vertical spin-1 dimers are taken as quantum ones with
Heisenberg bilinear and biquadratic interactions and with single-ion
anisotropy, while all interactions between spin-1 and spin-1/2 residing on the
intermediate sites are taken in the Ising form. The detailed analysis of the
ground state phase diagram is presented. The phase diagrams have shown to
be rather rich, demonstrating large variety of ground states: saturated one,
three ferrimagnetic with magnetization equal to 3/5 and another four
ferrimagnetic ground states with magnetization equal to 1/5. There are also two
frustrated macroscopically degenerated ground states which could exist at zero
magnetic filed.
Solving the model exactly within classical transfer-matrix formalism we
obtain an exact expressions for all thermodynamic function of the system. The
thermodynamic properties of the model have been described exactly by exact
calculation of partition function within the direct classical transfer-matrix
formalism, the entries of transfer matrix, in their turn, contain the
information about quantum states of vertical spin-1 XXZ dimer (eigenvalues of
local hamiltonian for vertical link).Comment: 14 pages, 9 figure
Evolució i tendències en l'ocupació del sòl a les illes balears
Se analizan los cambios de ocupación del suelo en las Islas Baleares para el período 1956-2000,
así como los potenciales de crecimiento que posibilitan los planes territorial, profundizando en el
estudio de las cubiertas del suelo urbano-industriales, que tienen la origen en la explosión turísticoinmobiliaria
de las Islas Baleares. La transformación territorial que resulta de la incorporación de
las islas Baleares al capitalismo global hace que estas cubiertas urbano-industriales pasen de ocupar
7.416 Ha (1956) a 28.746 Ha (2000). A partir de los planes vigentes, la cubierta urbano-industrial
podría alcanzar, potencialmente, unas 38.120 Ha para el 2015, con la siguiente distribución de superficies:
urbano (32.360 Ha), viario (2966 Ha), ferroviario (252 Ha), golf (1189 Ha) y canteras (1353 Ha).This study analyses the changes in land use in the Balearic Islands during the 1956-2000 period
and the growth potential generated by the planning policy, while examining the industrial and
urban coverage of land caused by the tourism and real estate boom in the Islands. The land transformation
stemming from the Balearic Islands’ entry into global capitalism gave rise to the growth
of urban and industrial land, which went from 7,416 ha. in 1956 to 28,746 ha. in 2000. Based on the
current planning model, the urban and industrial coverage could potentially reach some 38,120 ha.
by around 2015, with the following distribution: urban (32,360 ha.), roads (2966 ha.), railway (252
ha.), golf (1189 ha.) and quarries (1353 ha.)
Caliban en el pensamiento de Roberto Fernández Retamar
Distintas interpretaciones en literatura, historia y filosofía han problematizado el personaje y la categoría de Caliban. Perspectivas contemporáneas: Eagleton (2001), Frey (2000), Kirk (2006), Rebaza-Soraluz (2004) —sólo por mencionar algunos casos— enfrentan la cuestión de la resignificación simbólica de tal concepto. La finalidad del presente artículo es responder la siguiente interrogante: ¿ A partir de la formulación y el planteamiento que Fernández Retamar hace de lo posoccidental (como una ideología que permite comprender y superar a Occidente, es decir, como aquello con lo que América Latina, o Caliban, se ha estado “confrontando”) se puede llevar a cabo una reinterpretación del símbolo de Caliban, ahora con características posoccidentales? Con el análisis de dicha cuestión, se busca seguir adecuadamente la polémica clásica y contemporánea que al respecto, en literatura, historia y filosofía se encuentra disponible
Ética del discurso y Ética de la liberación: un diálogo que permite reflexionar la situación actual y global durante y después de la pandemia
Here I am interested in explaining some reasoning derived from the dialogue between Apel and Dussel, which allow us to understand the criterion or material principle from which Dussel contra argued the challenges and scope of discursive ethics. For the Latin American thinker, it is the criterion of life, a criterion that, in reality, had always been presupposed in the entire development of the ethics of Latin American liberation since its first version in 1973. I am going to base myself mainly on the work Ethics of Discourse and Ethics of Liberation, specifically in his works entitled: "The introduction of the Transformation of the philosophy of K.O. Apel and the philosophy of liberation", as well as "The reason of the Other. The act of interpellation as speaks”, where the criticism was made from the Other, from which it has been excluded from the communication community and from a community of economic life on which it had to be complementary with discursive ethics. These leads, on the one hand, to the Dusselian differentiation between validity and truth as aspects that are complementary and necessary, both as differentiated moments of the same process that implies ensuring human life. On the other hand, the dialogue between both ethics allows us to rethink the current and global situation of the coronavirus pandemic because the human fight for survival did not begin with the arrival of COVID-19, but with the exclusion of countless communities of life ago several decades
From feudal colonization to agrarian capitalism in Mallorca: Peasant endurance under the rise and fall of large states (1229-1900)
The colonization of Mallorca gave rise to a late-feudal agrarian society that evolved towards capitalism based on large estates owned by noblemen who hired large numbers of wage labourers from among smallholders living in agro-towns, the dispossessed remnants of a formerly wealthier peasantry. These well-off peasants originated from when the colonization frontier was open in the 13th and 14th centuries, but had been defeated when three peasant-plebeian revolts were crushed. Afterwards, Mallorca followed a latifundist transition towards agrarian capitalism similar to southern Italy or Spain, in sharp contrast with the middle-peasant paths seen in Catalonia or Valencia. The land rent rose, while agricultural wages fell from 1659 to 1800. Peasant families could not survive, and had to supplement wages with the products of their own plots. This set a socio-agroecological limit to growth in this agrarian class structure. The agrarian crisis at the end of the 19th century bankrupted the Mallorcan nobility. Bankers bought much of the land and sold it on as small allotments. This expanded the intensive cropping formerly limited to agro-town belts, giving rise to a new 'peasantization'. Despite their subordination, Mallorcan peasants had survived and created complex agroecological landscapes endowed with a rich biocultural heritage
Silencing mutant ataxin-3 rescues motor deficits and neuropathology in machado-joseph disease transgenic mice.
Machado-Joseph disease (MJD) or spinocerebellar ataxia type 3 (SCA3) is an autosomal dominantly-inherited neurodegenerative disorder caused by the over-repetition of a CAG codon in the MJD1 gene. This expansion translates into a polyglutamine tract that confers a toxic gain-of-function to the mutant protein - ataxin-3, leading to neurodegeneration in specific brain regions, with particular severity in the cerebellum. No treatment able to modify the disease progression is available. However, gene silencing by RNA interference has shown promising results. Therefore, in this study we investigated whether lentiviral-mediated allele-specific silencing of the mutant ataxin-3 gene, after disease onset, would rescue the motor behavior deficits and neuropathological features in a severely impaired transgenic mouse model of MJD. For this purpose, we injected lentiviral vectors encoding allele-specific silencing-sequences (shAtx3) into the cerebellum of diseased transgenic mice expressing the targeted C-variant of mutant ataxin-3 present in 70% of MJD patients. This variation permits to discriminate between the wild-type and mutant forms, maintaining the normal function of the wild-type allele and silencing only the mutant form. Quantitative analysis of rotarod performance, footprint and activity patterns revealed significant and robust alleviation of gait, balance (average 3-fold increase of rotarod test time), locomotor and exploratory activity impairments in shAtx3-injected mice, as compared to control ones injected with shGFP. An important improvement of neuropathology was also observed, regarding the number of intranuclear inclusions, calbindin and DARPP-32 immunoreactivity, fluorojade B and Golgi staining and molecular and granular layers thickness. These data demonstrate for the first time the efficacy of gene silencing in blocking the MJD-associated motor-behavior and neuropathological abnormalities after the onset of the disease, supporting the use of this strategy for therapy of MJD
Social Cognitive Theory and Health Care: Analysis and Evaluation
Social Cognitive Theory explains how different personal, environmental and cognitive factors influence human behavior and it has been an important source of knowledge in the social and health sciences. It has been employed in research and practice in nursing, the science of caring. However, no critical analysis has been conducted to show the impact of Social Cognitive Theory in nursing. This article aims to conduct an analysis and evaluation of Social Cognitive Theory using the Fawcett and DeSanto-Madeya methodological framework and a systematic search of the literature. Social Cognitive Theory showed that even though is a non-disciplinary theory of health sciences, the clarity and simplicity of its content facilitates its use in understanding and addressing different phenomena of caring, the creation of middle-range theories and in professional education. The contribution of Social Cognitive Theory in nursing science has focused mainly on two aspects: firstly, on improving disciplinary knowledge with the practical context of health caring by understanding human behavior and its integration in interventions for the promotion, prevention and treatment of health, and secondly, on nursing professionals’ education, highlighting the relevance of the interdisciplinary nature of knowledge
Socio-ecological transition in a Mediterranean agroecosystem: What energy flows tell us about agricultural landscapes ruled by landlords, peasants and tourism (Mallorca, 1860-1956-2012)
Using several energy returns on investment indicators (multi-EROI), this article analyses the socioecological transition of an agroecosystem in the western Mediterranean on the island of Mallorca (Spain) over a period of 150 years which saw a change from traditional organic farming to a fossil fuel-based system of agriculture. This circular bioeconomic analysis evaluates the agroecosystem's capacity to produce goods by reproducing itself in 1860, 1956 and 2012. In 1860 land and livestock were mostly in the hands of a few landowners, who kept agroecosystems away from the full productive capacity of traditional organic farming so as to increase land rents by lowering wages. The bankruptcy of these large estates increased peasant access to land at the end of the nineteenth and the first third of the twentieth centuries. Peasant farms were mainly solar-based and combined polyculture with a large number of small flocks, thus creating complex and attractive Mediterranean biocultural landscapes with higher EROIs. By 1956, these had practically reached the limits of traditional organic farming and early became a residual activity within the tourism specialization of the economy. As everywhere, conventional farming reduced agrarian eco-efficiency through production increases achieved at the cost of greater dependence on external fossil fuel-based inputs, a loss of biophysical circularity and lower EROIs. In Mallorca, however, this took place at the same time as agriculture was subsumed by the tourist economy, leading to a more partial and less widespread adoption of Green Revolution techniques than in other parts of Spain. Although agroecosystem live funds were undermined and the reproduction of Mallorcan biocultural landscapes was placed at risk, an important heritage of biocultural peasant agriculture still survives as a resource for the future
Chemical Composition of the Biomass of Saccharomyces cerevisiae - (Meyen ex E. C. Hansen, 1883) Yeast obtained from the Beer Manufacturing Process
Brewer's yeast was subjected to analytical studies to determine the chemical composition of its biomass. To this end, traditional methods of analysis were used to determine ribonucleic acid (RNA), mineral elements, amino acids and fatty acids. The results showed that proteins (49.63%), carbohydrates (31.55%), minerals (7.98%), RNA (8.12%) and total lipids (4.64%) predominate in the biomass composition. The amino acid profile of the protein is suitable for human nutrition, exceeding the recommendations from the FAO/WHO/UNU for essential amino acids. It is particularly rich in lysine and could be recommended as protein supplement in cereals. It was also observed that the yeast was an excellent source of some microelements, such as selenium, chromium, nickel and lithium; that it is also a good source of dietary fiber, particularly soluble fibers; and that the content of lipids was low, with a predominance of saturated and mono-unsaturated fatty acids with 10, 16 and 18 carbon atoms
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