42 resultados para ecological anatomy

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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Gross dissection for demonstrating anatomy of the human pelvis has traditionally involved one of two approaches, each with advantages and disadvantages. Classic hemisection in the median plane through the pelvic ring transects the visceral organs but maintains two symmetric pelvic halves. An alternative paramedial transection compromises one side of the bony pelvis but leaves the internal organs intact. The authors propose a modified technique that combines advantages of both classical dissections. This novel approach involves dividing the pubic symphysis and sacrum in the median plane after shifting all internal organs to one side. The hemipelvis without internal organs is immediately available for further dissection of the lower limb. The hemipelvis with intact internal organs is ideal for showing the complex spatial relationships of the pelvic organs and vessels relative to the intact pelvic floor.

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This article presents the implementation and validation of a dose calculation approach for deforming anatomical objects. Deformation is represented by deformation vector fields leading to deformed voxel grids representing the different deformation scenarios. Particle transport in the resulting deformed voxels is handled through the approximation of voxel surfaces by triangles in the geometry implementation of the Swiss Monte Carlo Plan framework. The focus lies on the validation methodology which uses computational phantoms representing the same physical object through regular and irregular voxel grids. These phantoms are chosen such that the new implementation for a deformed voxel grid can be compared directly with an established dose calculation algorithm for regular grids. Furthermore, separate validation of the aspects voxel geometry and the density changes resulting from deformation is achieved through suitable design of the validation phantom. We show that equivalent results are obtained with the proposed method and that no statistically significant errors are introduced through the implementation for irregular voxel geometries. This enables the use of the presented and validated implementation for further investigations of dose calculation on deforming anatomy.

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The present study was conducted to assess the interrelation between teat anatomy and machine milking in dairy buffaloes raised in Switzerland. A 3-min pre-stimulation induced milk ejection before cluster attachment in most cases and caused an optimal milk removal during machine milking. In an additional experiment, longitudinal cross-section ultrasound was obtained before and after a 3-min pre-stimulation. Teat wall thickness, teat diameter, cisternal diameter and teat canal length were evaluated. It was observed that 3-min pre-stimulation dramatically reduced teat canal length whereas all the other anatomical parameters remained unchanged. The vacuum needed to open the teat canal was also measured before and after a 3-min pre-stimulation by using a special teat cup with only the mouthpiece of the liner remaining on the top of the teat cup (no liner, no pulsation). Without pre-stimulation but after wetting the teat canal by stripping one squirt of milk out of the teat, no milk could be withdrawn with a vacuum up to 39 kPa. However, after pre-stimulation, milk flow occurred in all buffaloes at a vacuum between 16 and 38 kPa. In the last experiment, the teat tissue was examined in slaughtered buffaloes and compared with teat tissue of cows. No difference was noted in histological sections and teat canal length was similar in cows and buffaloes. Proximal to the teat canal, the teat did not pass into an open cistern but the lumen was collapsed. In conclusion, buffaloes need to be well pre-stimulated because the tissue above the teat canal provides additional teat closure before milk ejection. Therefore, milk can only be obtained after pre-stimulation.

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Hatchery fish stocking for stock enhancement has been operated at a massive and global scale. However, the use of hatchery fish as a means of stock enhancement is highly controversial, and little is known about its effects on wild stock and consequences for stock enhancement. Here we review the scientific literature on this subject in order to address a fundamental - question is hatchery stocking a help or harm for wild stock and stock enhancement? We summarized 266 peer-reviewed papers that were published in the last 50 years, which describe empirical case studies on ecology and genetics of hatchery stocks and their effects on stock enhancement. Specifically, we asked whether hatchery stock and wild stock differed in fitness and the level of genetic variation, and whether stocking affected population abundance. Seventy studies contained comparisons between hatchery and wild stocks, out of which 23 studies showed significantly negative effects of hatchery rearing on the fitness of stocked fish, and 28 studies showed reduced genetic variation in hatchery populations. None of these studies suggested a positive genetic effect on the fitness of hatchery-reared individuals after release. These results suggest that negative effects of hatchery rearing are not just a concern but undeniably present in many aquaculture species. In a few cases, however, no obvious effect of hatchery rearing was observed, and a positive contribution of hatchery stock to the abundance of fish populations was indicated. These examples suggest that there is a chance to improve hatchery practices and mitigate the negative effects on wild stocks, although scientific data supporting the positive effect on stock enhancement are largely missing at this moment. Technically, microsatellite-based parentage assignments have been proven as a useful tool for the evaluation of reproductive fitness in natural settings, which is a key for stock enhancement by hatchery-based stocking. We discuss implications of these results, as well as their limitations and future directions. (C) 2010 Elsevier B.V. All rights reserved.

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Nerve blocks and radiofrequency neurotomy of the nerves supplying the cervical zygapophyseal joints are validated tools for diagnosis and treatment of chronic neck pain, respectively. Unlike fluoroscopy, ultrasound may allow visualization of the target nerves, thereby potentially improving diagnostic accuracy and therapeutic efficacy of the procedures. The aims of this exploratory study were to determine the ultrasound visibility of the target nerves in chronic neck pain patients and to describe the variability of their course in relation to the fluoroscopically used bony landmarks.

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Giulio Cesare Aranzio in Italian (Julius Caesar Arantius in Latin) has not received full acclaim for his achievements in the field of anatomy and surgery that remain unknown to most physicians. His anatomical books Observationes Anatomicas, and De Humano Foetu Opusculum and surgical books De Tumoribus Secundum Locos Affectos and Hippocratis librum de vulneribus capitis commentarius brevis printed in Latin and additional existing literature on Aranzio from medical history books and journals were analysed extensively. Aranzio became Professor of Anatomy and Surgery at the University of Bologna in 1556. He established anatomy as a distinguished branch of medicine for the first time in medical history. Aranzio combined anatomy with a description of pathological processes. He discovered the 'Nodules of Aranzio' in the semilunar valves of the heart. He gave the first description of the superior levator palpebral and the coracobrachialis muscles. Aranzio wrote on surgical techniques for a wide spectrum of conditions that range from hydrocephalus, nasal polyp, goitre and tumours to phimosis, ascites, haemorrhoids, anal abscess and fistulae, and much more. Aranzio had an extensive knowledge in surgery and anatomy based in part on the ancient Greek and his contemporaries in the 16th century but essentially on his personal experience and practice.

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Seventeen polycyclic aromatic hydrocarbons (PAHs) were studied in surface waters (including particulate phase) from the Chenab River, Pakistan and ranged from 289-994 and 437-1290 ng l-1 in summer and winter (2007-09), respectively. Concentrations for different ring-number PAHs followed the trend: 3-rings > 2-rings > 4-rings > 5-rings > 6-rings. The possible sources of PAHs are identified by calculating the indicative ratios; appropriating petrogenic sources of PAHs in urban and sub-urban regions with pyrogenic sources in agricultural region. Factor analysis based on principal component analysis identified the origins of PAHs from industrial activities, coal and trash burning in agricultural areas and municipal waste disposal from surrounding urban and sub-urban areas via open drains into the riverine ecosystem. Water quality guidelines and toxic equivalent factors highlighted the potential risk of low molecular weight PAHs to the aquatic life of the Chenab River. The flux estimated for PAHs contaminants from the Chenab River to the Indus River was >50 tons/year.

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