962 resultados para Lusitano horse
Resumo:
Recognising the growing significance of sport and recreation in the countryside, this paper seeks to examine the changing demand for, and supply of, opportunities for horse riding in the countryside. It considers the physical problems associated with horse riding, together with the changing social context. The paper considers possible solutions to the issues raised, both within existing rights of way legislation and via new opportunities created by the revisions to agricultural support that have occurred in the last decade. The paper concludes that while the new opportunities have ameliorated some of the problems associated with the supply of land for horse riding, no new rights of access have been conferred. The ability of horse riders to guarantee continued provision will be governed partially by the market but also by future agricultural support policy.
Resumo:
Despite decades of research, the roles of climate and humans in driving the dramatic extinctions of large-bodied mammals during the Late Quaternary period remain contentious. Here we use ancient DNA, species distribution models and the human fossil record to elucidate how climate and humans shaped the demographic history of woolly rhinoceros, woolly mammoth, wild horse, reindeer, bison and musk ox. We show that climate has been a major driver of population change over the past 50,000 years. However, each species responds differently to the effects of climatic shifts, habitat redistribution and human encroachment. Although climate change alone can explain the extinction of some species, such as Eurasian musk ox and woolly rhinoceros, a combination of climatic and anthropogenic effects appears to be responsible for the extinction of others, including Eurasian steppe bison and wild horse. We find no genetic signature or any distinctive range dynamics distinguishing extinct from surviving species, emphasizing the challenges associated with predicting future responses of extant mammals to climate and human-mediated habitat change.
Resumo:
This paper presents direct radiocarbon measurements on horse skeletal remains from the Beaker period settlement at the site of Newgrange in Ireland, finds which have previously been argued as the earliest domestic horses in Ireland. The new determinations date the horse remains to the Irish Iron Age and shed important new light on the introduction of domestic horses to Ireland and to north-west Europe more generally. Although the new dates undermine the idea for the introduction of horses as part of a ‘Beaker package’, the early use of horse is not well defined archaeologically or chronologically and the earliest use of domestic horses in Ireland and Britain is still uncertain. This paper also identifies evidence for heavy bitting damage on the Iron Age Newgrange horse teeth and presents some possible parallels between the evidence from Newgrange and that at Tara, which has been previously linked with kingship rituals
Resumo:
There is a period of some 5000 years or so in the prehistory of Europe when horse populations were greatly depleted and perhaps even disappeared in many places. Before this time, during the Upper Palaeolithic, wild horses were common; after, during the Bronze Age, domestic horses were being raised and used across Europe. What happened in between is uncertain, in part because of the sketchy archaeological record. Debates continue as to the origins (the when, where and how) of Europe's domestic horses, including whether horse husbandry dispersed only from habitats favourable to horses on the Eurasian steppes or whether there was local domestication in temperate Europe. This paper reviews the evidence for the transition from wild horses to domestic horses in Europe.
Resumo:
This paper describes a simple technique for the patterning of glia and neurons. The integration of neuronal patterning to Multi-Electrode Arrays (MEAs), planar patch clamp and silicon based ‘lab on a chip’ technologies necessitates the development of a microfabrication-compatible method, which will be reliable and easy to implement. In this study a highly consistent, straightforward and cost effective cell patterning scheme has been developed. It is based on two common ingredients: the polymer parylene-C and horse serum. Parylene-C is deposited and photo-lithographically patterned on silicon oxide (SiO2) surfaces. Subsequently, the patterns are activated via immersion in horse serum. Compared to non-activated controls, cells on the treated samples exhibited a significantly higher conformity to underlying parylene stripes. The immersion time of the patterns was reduced from 24 to 3 h without compromising the technique. X-ray photoelectron spectroscopy (XPS) analysis of parylene and SiO2 surfaces before and after immersion in horse serum and gel based eluant analysis suggests that the quantity and conformation of proteins on the parylene and SiO2 substrates might be responsible for inducing glial and neuronal patterning.
Resumo:
While it was happening, European expansion was often legitimised by evoking frontier images: pioneers setting off from the metropolis, penetrating wilderness in order to open access to resources, like minerals, living-space, and fertile lands. Central to the ideology of the frontier is the notion of 'no-man's land'. These 'pioneers', however, often had to face local inhabitants and their interpretations and uses of this land. Thus it will be argued that contestations over landscape were at the same time battles over the legitimation of European expansion, as well as over local perceptions of this process. Ideologically, contestations by Europeans and Africans become apparent in the sexualisation of landscape. This paper is based on the case study of a Valley in eastern Zimbabwe on the border with Mozambique, and more specifically of two tea estates which were established in the rainforest. Unusually late for the region, European influence in this remote area only began to become significant in the 1950s which were an important turning point regarding land and landscape in the area. These years of great change will be analysed in order to map out different strands of interest by the main parties involved. It will be demonstrated that their readings of landscape translated into contestations over land. A recent example of such a conflict will be given.
Resumo:
Resistance of bacteria to phages may be gained by alteration of surface proteins to which phages bind, a mechanism that is likely to be costly as these molecules typically have critical functions such as movement or nutrient uptake. To address this potential trade-off, we combine a systematic study of natural bacteria and phage populations with an experimental evolution approach. We compare motility, growth rate and susceptibility to local phages for 80 bacteria isolated from horse chestnut leaves and, contrary to expectation, find no negative association between resistance to phages and bacterial motility or growth rate. However, because correlational patterns (and their absence) are open to numerous interpretations, we test for any causal association between resistance to phages and bacterial motility using experimental evolution of a subset of bacteria in both the presence and absence of naturally associated phages. Again, we find no clear link between the acquisition of resistance and bacterial motility, suggesting that for these natural bacterial populations, phage-mediated selection is unlikely to shape bacterial motility, a key fitness trait for many bacteria in the phyllosphere. The agreement between the observed natural pattern and the experimental evolution results presented here demonstrates the power of this combined approach for testing evolutionary trade-offs.
Resumo:
Background Pseudomonas syringae can cause stem necrosis and canker in a wide range of woody species including cherry, plum, peach, horse chestnut and ash. The detection and quantification of lesion progression over time in woody tissues is a key trait for breeders to select upon for resistance. Results In this study a general, rapid and reliable approach to lesion quantification using image recognition and an artificial neural network model was developed. This was applied to screen both the virulence of a range of P. syringae pathovars and the resistance of a set of cherry and plum accessions to bacterial canker. The method developed was more objective than scoring by eye and allowed the detection of putatively resistant plant material for further study. Conclusions Automated image analysis will facilitate rapid screening of material for resistance to bacterial and other phytopathogens, allowing more efficient selection and quantification of resistance responses.
Resumo:
In spite of numerous, substantial advances in equine reproduction, many stages of embryonic and fetal morphological development are poorly understood, with no apparent single source of comprehensive information. Hence, the objective of the present study was to provide a complete macroscopic and microscopic description of the equine embryo/fetus at various gestational ages. Thirty-four embryos/fetuses were aged based on their crown rump length (CRL), and submitted to macroscopic description, biometry, light and scanning microscopy, as well as the alizarin technique. All observed developmental changes were chronologically ordered and described. As examples of the main observed features, an accentuated cervical curvature was observed upon macroscopic examination in all specimens. In the nervous system, the encephalic fourth ventricle and the encephalic vesicles forebrain, midbrain, and hindbrain, were visualized from Day 19 (ovulation = Day 0). The thoracic and pelvic limbs were also visualized; their extremities gave rise to the hoof during development from Day 27. Development of other structures such as pigmented optical vesicle, liver, tail, cardiac area, lungs, and dermal vascularization started on Days 25, 25, 19, 19, 34, and 35, respectively. Light and scanning microscopy facilitated detailed examinations of several organs, e.g., heart, kidneys, lungs, and intestine, whereas the alizarin technique enabled visualization of ossification. Observations in this study contributed to the knowledge regarding equine embryogenesis, and included much detailed data from many specimens collected over a long developmental interval. (C) 2011 Elsevier Inc. All rights reserved.
Resumo:
Quantity and variety of environmental antigens, age, diet, vaccine protocols, exercising practice and mucosal cytokine microenvironment are factors that influence serum immunoglobulin (Ig) levels. IgA, IgG, IgG(T) and IgM were quantified in 60 horses, which were classified into two groups, `intensive` or `relaxed`, according to sanitary standards of the facilities and physical exercise to which animals were subjected to. The `intensive` group presented lower means for all isotypes, but only IgA presented a significant (P < 0.0064) difference when compared to the `relaxed` group. This suggests that mucosal immunity found in the `intensive` group is lower when compared to the `relaxed` group. Our data suggest that athlete horses may be less poised to mount an effective mucosal immunity response to environmental challenges and should not be considered by the same perspectives as a free-ranging horse.
Resumo:
Cytochrome c exhibits two positively charged sites: site A containing lysine residues with high pK(a) values and site L containing ionizable groups with pK(aobs),values around 7.0. This protein feature implies that cytochrome c can participate in the fusion of mitochondria and have its detachment from the inner membrane regulated by cell acidosis and alkalosis. In this study, We demonstrated that both horse and tuna cytochrome c exhibited two types of binding to inner mitochondrial membranes that contributed to respiration: a high-affinity and low-efficiency pi-I-independent binding (microscopic dissociation constant K(sapp2), similar to 10 nM) and a low-affinity and high-efficiency pH-dependent binding that for horse cytochrome c had a pK(a) of similar to 6.7. For tuna cytochrome c (Lys22 and His33 replaced with Asn and Trp, respectively), the effect of pH on K(sapp1), was less striking than for the horse heme protein, and both tuna and horse cytochrome c had closed K(sapp1) values at pH 7.2 and 6.2, respectively. Recombinant mutated cytochrome c H26N and H33N also restored the respiration of the cytochrome c-depleted mitoplast in a pH-dependent manner. Consistently, the detachment of cytochrome c from nondepleted mitoplasts was favored by alkalinization, suggesting that site Lionization influences the participation of cytochrome c in the respiratory chain and apoptosis.
Resumo:
The alpha-aminoketone 1,4-diamino-2-butanone (DAB), a putrescine analogue, is highly toxic to various microorganisms, including Trypanosoma cruzi. However, little is known about the molecular mechanisms underlying DAB`s cytotoxic properties. We report here that DAB (pK(a) 7.5 and 9.5) undergoes aerobic oxidation in phosphate buffer, pH 7.4, at 37 degrees C, catalyzed by Fe(II) and Cu(II) ions yielding NH(4)(+) ion, H(2)O(2), and 4-amino-2-oxobutanal (oxoDAB). OxoDAB, like methylglyoxal and other alpha-oxoaldehydes, is expected to cause protein aggregation and nucleobase lesions. Propagation of DAB oxidation by superoxide radical was confirmed by the inhibitory effect of added SOD (50 U ml(-1)) and stimulatory effect of xanthine/xanthine oxidase, a source of superoxide radical. EPR spin trapping studies with 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) revealed an adduct attributable to DMPO-HO(center dot), and those with alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone or 3,5-dibromo-4-nitrosobenzenesulfonic acid, a six-line adduct assignable to a DAB(center dot) resonant enoyl radical adduct. Added horse spleen ferritin (HoSF) and bovine apo-transferrin underwent oxidative changes in tryptophan residues in the presence of 1.0-10 mM DAB. Iron release from HoSF was observed as well. Assays performed with fluorescein-encapsulated liposomes of cardiolipin and phosphatidylcholine (20:80) incubated with DAB resulted in extensive lipid peroxidation and consequent vesicle permeabilization. DAB (0-10 mM) administration to cultured LLC-MK2 epithelial cells caused a decline in cell viability, which was inhibited by preaddition of either catalase (4.5 mu M) or aminoguanidine (25 mM). Our findings support the hypothesis that DAB toxicity to several pathogenic microorganisms previously described may involve not only reported inhibition of polyamine metabolism but also DAB pro-oxidant activity. (C) 2011 Elsevier Inc. All rights reserved.
Resumo:
It is shown that metal complexes of the biodegradable ligand ethylenediaminedisuccinic acid (edds) present antimicrobial activity towards fungi and bacteria. [Cd(edds)], in particular, is more toxic than free Cd2+ to Aspergillus niger, behaving as a `Trojan Horse` in the facilitated delivery of the toxic metal into the fungus.
Resumo:
The purpose of this essay is to examine and explain how the Swedish mining court of Stora Kopparberget (the Great Copper Mountain) implemented its judicial legislation between 1641-1682. Questions are asked about which counts of indictments the court tried, which sentences they handed out, in what quantities and how these results looks in comparison with other contemporary courts. The index cards of the court judicial protocols are the primary source of information. The methods are those of quantity- and comparative analysis.The results show that theft of copper ore was the most common crime ransacked by the court. Other common crimes were (in order): sin of omission, transgression of work directions, fights, slander and disdain, trade of stolen ore, failing appearance in court etc.Fines were by far the most common sentence followed by shorter imprisonments, gauntlets, loss of right to mine possession, twig beating, loss of work, penal servitude, banishment, “wooden horse riding” and finally military transcription. Even though previous re-search, in the field of Swedish specialized courts, is almost non existent evidence confirms great similarities between the Stora Kopparberget mining court and Sala mining court. This essay will, hopefully, enrich our knowledge of specialized courts, of 17th century mining industry and society and let us reach a broader understanding of the working conditions of the mountain.
Resumo:
Not to put the cart before the horse: clarification of Mead’s ”role taking” George Herbert Mead’s “role taking” is subject to many interpretations. Some dominant definitions restrict role taking to reflective people trying to understand each other and taking on each others' roles. Other definitions restrict role taking to the stage of a developed language. Against these two types of definitions I assert that Meads concept is explanatory, not merely descriptive, functionally as well as existentially. It has a value also on elementary levels of human development, where man is socially similar to other primates. Swedish sociologists have contributed fruitfully to straighten the debate. My intention is to clarify it further, and to explicate my own interpretation. Basic role taking is a non-reflective activity going on in any place where living entities influence each other with gestures in similar ways. In human beings it gives rise to conscious discursive reflectivity, and it coincides phylogenetically and ontogenetically with development of language, rather than being created by it. Role taking emanates from breaking automatic responsivity. It introduces distance and reflectivity and results in conscious social behavior, rather than being produced by such. In this way, role taking is a major step in the development of intelligence on earth.