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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
381

Deformačně napěťová analýza prasečího femuru / Strain-Stress analysis of pig femur

Legerský, Radek January 2011 (has links)
This master’s thesis deals with the strain-stress analyses of the pig femoral bone in physiological and pathological condition. Pathological condition is determined by a significant defect in diaphysis of the bone fixed by using direct angular stable locking plate with screws. The thesis describes the creation of computational models with special focus on bone tissues models of material, which are based on analysis of digital images from computed tomography (CT). There are created and analyzed three types of computational models: the first one corresponds to physiological condition of femur, the second one to femur with significant defect and fixation plate and the third one to femur with significant defect, fixation plate and rod. Every model is loaded in three ways: the first of them simulating the experimental conditions of pressure testing of the femur, the second one bone stress in the sagittal plane and the third one stress by using load determined from probational release of the pig hind limb. Strain-stress states are determined by finite element method using Ansys computational system. Gained results of stress and strain are compared with experimental measurements. The thesis presents a basic idea of the mechanical behavior of porcine femur and porcine femur with significant bone defect.
382

Influence des stratégies de stimulation électrique des implants cochléaires sur les réponses neuronales du cortex auditif du cobaye / Influence of Electrical Stimulation Strategies in Cochlear Implants on Evoked Responses Recorded in the Guinea Pig Auditory Cortex

Adenis, Victor 30 November 2018 (has links)
L’implant cochléaire, la neuroprothèse la plus répandue et la plus réussie de nos jours, permet à des sujets sourds profonds de récupérer une perception auditive permettant une compréhension du langage. Bien que les technologies et les processeurs actuels aient grandement évoluées depuis ces vingt dernières années, la stratégie optimale pour coder l'intensité sonore dans l’implant n’a pas encore été trouvée. L'accès à des indices physiologiques est difficile chez le patient humain alors qu’il est relativement simple chez l’animal. Le but de cette thèse était de développer un modèle animal (cobaye) d'implantation cochléaire et d'étudier la réponse du système auditif à différentes stratégies de stimulation. Les réponses du nerf auditif et des neurones du cortex auditif primaire ont été obtenues lors de stimulations via un implant cochléaire simplifié.Nous avons observé que l’importante variabilité inter-individuelle dans l’efficacité de 2 stratégies (augmentation d’amplitude vs. de durée des pulses électriques) à augmenter les réponses du nerf auditif se répercute au niveau du cortex auditif. Les tests de nouvelles formes de pulses (pulses asymétriques ou en rampes) sur les réponses des neurones corticaux suggèrent que ce type de pulses permettrait de réduire l’étendue corticale activée par la stimulation électrique même aux charges les plus élevées. Là aussi, une importante variabilité inter-individuelle a été observée. Cela a conduit à ce que les activations corticales les plus proches de l’activation normalement observée par des sons purs, soient obtenues soit avec une forme de pulses soit une autre. Cette thèse prône donc qu’il est indispensable d’avoir accès à de nombreuses stratégies de stimulation sur chaque sujet afin de choisir celle la plus adaptée pour un patient donné. / Cochlear implant, the most successful neuroprosthesis allows deaf subjects to recover auditory perception and speech intelligibility. Over the last decades, the technology and the coding strategies in cochlear implants have been largely improved but the optimal strategy for coding loudness is still problematic. Human studies face a lot of restrictions especially regarding the collection of electrophysiological events. The primary goal of this thesis is to develop an animal model (guinea pig) of implantation and to study the auditory system's responses for different strategies for coding sound loudness (increase in amplitude vs. duration of electrical pulses). We studied the responses of the auditory nerve and primary auditory cortex obtained with electrical stimulation delivered through a simplified cochlear implant.We observed that the large inter-individual variability in the efficacy of these two classical strategies for increasing auditory nerve responses is reflected in the auditory cortex. Testing new forms of pulses (asymmetric pulses or ramped pulses) suggests that this type of pulses would reduce the evoked responses of cortical neurons even at the highest injected charges. Again, a large inter-individual variability was observed. As a consequence, for each animal, the cortical response the closest from the activation normally observed with pure tones, is obtained either with one form of pulses or another. This thesis advocates that it is essential to have access to several stimulation strategies on each subject in order to choose the most appropriate for a given patient.
383

Roggeneinsatz in der Schweinemast

Alert, Hans-Joachim, Fröhlich, Brigitte 28 August 2006 (has links)
Noch vor 50 Jahren stand Roggen an erster Stelle im Getreideanbau, erst mit Abstand folgte der Weizen . Gerste wurde meist nur als Sommerfrucht angebaut und der Mais war noch ein Exot. Die Pflanzenzüchtung bewirkte eine grundlegende Änderung der Anbaugewohnheiten. Roggen erwies sich bei der züchterischen Verbesserung als schwieriger und sein langes Stroh störte bei der Ernte mit dem Mähdrescher. Roggen wurde deshalb auf die geringerwertigeren Böden mit hohem Sandanteil abgedrängt. Durch eine neue Methode der Pflanzenzüchtung, die Hybridzüchtung, kann Roggen heute im Ertrag auf vielen Standorten wieder mit dem Weizen konkurrieren. Mit der vorliegenden Veröffentlichung wird erläutert, ob höhere Roggenanteile in der Ferkel- und Mastschweinefütterung vertretbar sind.
384

Leistungsprüfung bei Schweinen: Jahresbericht 2009 der LPA Köllitsch

Gschwender, Felicitas, Milich, Andrea 24 August 2010 (has links)
Im Prüfjahr 2009 erhielten 842 Tiere (davon 492 Eber der Deutschen Landrasse) einen Prüfabschluss. 39 Eber mit hervorragender Eigenleistung wurden durch den Mitteldeutschen Schweinezuchtverband e.V als Besamungseber angekauft. Der Jahresbericht dokumentiert den Prüfablauf und die Prüfergebnisse. Bei den geprüften Rassen wurden u.a. die Mast- und Schlachtleistung sowie die Fleischqualität untersucht. Die Durchführung der Leistungsprüfung erfolgt praxisnah in Gruppen mit elektronischer Einzeltiererkennung und tierindividueller Erfassung des Futterverzehrs. Es erfolgt eine kombinierte Eigenleistungs-, Geschwister- und Nachkommenprüfung mit hohem Anteil Ebereigenleistungsprüfung zur züchterisch effizienten Nutzung der Prüfkapazitäten. Grundlage der Prüfung, die seit 1995 im Lehr- und Versuchsgut Köllitsch durchgeführt wird, sind die bundeseinheitlichen »Richtlinien für die Stationsprüfung auf Mastleistung, Schlachtkörperwert und Fleischbeschaffenheit beim Schwein (Geschwister- und Nachkommenprüfung)«, die vom Zentralverband der Deutschen Schweineproduktion e.V. herausgegeben werden.
385

Vliv sourozenecké kompetice během přítomnosti u struku na mateřské chování u prasete domácího / Vliv sourozenecké kompetice během přítomnosti u struku na mateřské chování u prasete domácího

Leszkowová, Iva January 2013 (has links)
This diploma thesis deal with the neonatal sibling competition during nursing within first day after farrowing, focusing on maternal reaction on neonatal sibling competition during nursing. We predicted that the sow will terminate nursing by a changing posture or by a non- nutritive nursing (i.e. nursing without milk ejection) with increasing number of fights and screams. A total of 19 healthy sows and their litters were directly observed and video recorded during first day after farrowing for 6 h. The behaviour of piglets (fighting, screaming, presence at the udder) in the pre massage and the post massage was scored every 15 seconds. Piglets which missed milk ejection, posture changing of the sow and whether the nursing involve milk ejection were noted. A sum of fighting and screaming piglets in the pre massage and the post massage was calculated. A higher sum of fighting and screaming piglets correlated with a higher proportion of non-nutritive nursing (P<0.001) as well as with a higher proportion of sow posture changing in the pre massage (P<0.01). However, a higher sum of fighting and screaming piglets did not increase the probability of sow posture changing in the post massage. The results show a positive correlation between the litter size and the sum of fighting and screaming piglets in the...
386

Evolution and paleoecology of Pliocene Suidae (Artiodactyla, Mammalia) in the lower Awash Valley (Afar, Ethiopia): implications for hominin evolution and paleoenvironments

January 2018 (has links)
abstract: Providing an environmental context to early hominins is as important as describing the hominin fossils themselves, because evolutionary processes are tightly linked to everchanging ecosystems that vary across space and through time. An optimal understanding of ecosystems changes is critical to formulate and test hypotheses regarding human evolution and adaptation. Fortunately, the fossil record has yielded abundant remains of mammals which can be used to explore the possible causal relationships between environmental change and mammal – including hominin –evolution. Although many studies have already been conducted on this topic, most of them are framed at large spatial and temporal scales. Instead, this dissertation focuses on the evolution and paleoecology of only one group of mammals (the Suidae) in a specific geographical area (lower Awash Valley in Ethiopia) and within a constrained time frame (3.8–2.6 Ma). Three dissertation papers address: 1) changes in suid taxonomic composition in relation to Late Pliocene faunal turnover ~2.8 Ma in the Lee-Adoyta basin, Ledi-Geraru; 2) comparisons of suid diets from Hadar (~3.45–2.95 Ma) with respect to those of Kanapoi (~4.1 Ma, West Turkana, Kenya); 3) the dietary ecology of the suids from Woranso-Mille (~3.8–3.2 Ma). Results of these papers show that 1) after ~2.8 Ma there is a replacement of suid species that is coupled with low relative abundance of suids. This is compatible with more open and/or arid environments at this time; 2) suid dietary breadth was broader in Hadar than in Kanapoi, but this is mostly driven by the dietary niche space occupied by Kolpochoerus in Hadar, a suid genus absent from Kanapoi; 3) suid diets vary both temporally and geographically within the lower Awash Valley. Kolpochoerus incorporates more C4 resources (e.g., grasses) in its diet after ~3.5 Ma and in general, suids after ~3.5 Ma in Woranso-Mille had C4-enriched diets in comparison with those from nearby Hadar and Dikika. Presumably, the changes in suid communities (relative abundance and taxonomic composition) and dietary shifts observed in suids were triggered by climatic and habitat changes that also contributed to shape the behavioural and morphological evolution of early hominins. / Dissertation/Thesis / Doctoral Dissertation Anthropology 2018
387

Continuous Measurements of the Pig-Iron Temperature

Björn, Linnéa, Forslin, Malin January 2012 (has links)
This report is about continuous temperature measurements of pig-iron at tapping from blast furnace 2 in Oxelösund, SSAB. Nowadays the temperature is only checked once at every tapping. The purpose of this project is to see if the process stability increases by continuously knowing the temperature and to compare the costs of this new technique with the technique used today. Possible savings due to less consumption of coke/coal if the silicon amount and the temperature are closer to their aim values will be regarded and if as little steam consumption as possible are used. The process stability can be divided into different sub goals. The ordinary measuring techniques were investigated as a part of the main goal; such as the ordinary measured temperature, the pig-iron and slag samples. The new continuous temperature measuring technique was compared with the ordinary temperature measurement and investigations of the life length were done. How representative the pig-iron and slag samples are, when taking them at the time they are today, are also looked into. The continuous measured temperature showed around 0,37 % higher temperature than the ordinary measured temperature. The pig-iron and slag samples should be taken as they are today, for mainly safety aspects. By using continuous temperature measurement, some of the sub goals can be achieved for a more stable process. The economy on the other hand has shown that large savings can be done by using this continuous temperature method due to a more stable process. This is mainly because of a decrease in steam usage in the experimental period. By regarding only the material of the methods the continuous temperature equipment is a bit more expensive, but the savings are much larger so the continuous temperature method is beneficial. With time this method could probably improve the process stability even more since the operators will deal with the information and the probe better.
388

Effects of an External Oscillation Device on Phonation Threshold Pressure (PTP)

Jones, Brittany Tiffany 08 June 2022 (has links)
The purpose of the present study was to examine the effects of external laryngeal vibration on voice function. The current study was based on a recent pilot study using silicone vocal folds that demonstrated a decrease in phonation threshold pressure (PTP; cmH2O) when an external oscillation was applied to the vocal folds. Using a within-subjects experimental design, a custom external oscillatory device was fitted to the posterior portion of 12 excised pig larynges using a traditional benchtop phonation setup. For each larynx, phonation was elicited during 30 repeated trials, including 15 with and 15 without external oscillation. During the phonation trials, aerodynamic measures were collected. The outcome measure for this study was PTP, which has been established in the literature as being correlated with physiologic and self-perceived vocal effort. Furthermore, PTP is used routinely as an aerodynamic indicator of voice function, vocal efficiency, and the nature and severity of voice disorders. Although the aim was to quantify either positive (i.e., PTP decrease) or negative (i.e., PTP increase) effects of external oscillation on PTP, it was hypothesized that external oscillation would result in a reduction in average PTP values. The results of the study indicate that application of an external oscillatory device results in significantly lower PTP. These findings have important clinical implications for PTP signal acquisition and the potential use of external oscillation as a therapeutic tool to improve voice function.
389

A Comparison of Phonation Threshold Pressure and Phonation Threshold Flow Between Pig and Rabbit Benchtop-Mounted Larynges

Prigmore, Amber Christeen 03 April 2020 (has links)
Animal models are used extensively in voice research to study aspects of phonation, including physiology, kinematics, structure, and histology. Animals such as dog, cow, pig, sheep, deer, monkey, ferret, and rabbit have been used in voice research, with pig being one of the most common models. It is thought that the pig larynx is highly similar to the human larynx and one of the best models used in animal translational research. As with any model, however, the pig larynx does have some limitations. Perhaps a limitation most important to the rationale of this investigation is that pigs are difficult animals to study in vivo. Maintenance for a pig is challenging due to its large size and the variability of phonation use in the animal. Therefore, viable and practical alternatives are needed for in vivo voice research. The current study collected preliminary normative data from an alternate animal model, the rabbit, which has been used more recently in studies to model human phonation. The rabbit model was chosen due to its histological similarities to humans, in vivo phonation patterns, size, and practicality. The rabbit represents a more practical model for some longitudinal designs, as well as ex vivo phonatory models with aerodynamic measures as the primary variables. The current study involved a comparison of two aerodynamic measures, specifically phonation threshold pressure (PTP) and phonation threshold flow (PTF) between two groups, pig and rabbit larynges. The purpose of this study was to determine normative aerodynamic values for rabbits and to compare these with normative values for pigs during excised larynx benchtop phonation. Each group consisted of 15 larynges that were finely dissected to reveal the true vocal folds. Each larynx was then connected to a pseudolung and humidified air was passed through it. Fifteen phonation trials were elicited and the results averaged for each larynx. The results indicated that PTP and PTF were significantly different between the two groups, with PTP and PTF being lower for the rabbit group. Additionally, PTP values for rabbits were closer than pigs to the typical human value; however, some methodological challenges to rabbit benchtop models, including size and structural integrity, also exist. But the results from this study indicate that rabbits should be considered a viable option for voice research that would be more feasible with a small animal option that translates well to humans than a large animal option.
390

Neverbální chování seniorů při zooterapii / Nonverbal behaviour of elderly people during animal-assisted activity

Lupienská, Natálie January 2011 (has links)
Bc. Natálie Lupienská: Nonverbal behaviour of elderly people during animal-assisted activity Abstract The aim of the study is to compare nonverbal behaviour of elderly people in three studied interactions: 1) with a therapeutic animal, specifically guinea-pig (Cavia aperea porcellus), 2) with a plush guinea-pig toy and 3) with an ordinary single-coloured cup. Twenty one elderly people (3 men and 18 women, average age of 85 years, SD 7,95 y) participated in the study. All data used for the purpose of the study (video recordings) were collected in a Prague residential house for elderly people in summer 2009. An ethogram composed of sixty elements was prepared. Consequently the Interact software was used for coding of those elements. The inter-subject comparison demonstrated that a guinea-pig significantly enhances an interest in an object and tactile behaviour of observed people. There was no significant difference between the three examined situations in terms of respondent's communication with a therapist, facial expressions or the overall activity. Keywords: nonverbal behaviour, animal-assisted activity, elderly, guinea-pig

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