• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 1
  • 1
  • Tagged with
  • 5
  • 5
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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.
1

A FEEDBACK CONTROL OF ACTIVE OMNIDIRECTIONAL TREADMILL SYSTEM FOR DROSOPHILA

Pun, Pikam 01 August 2019 (has links)
The study on animal models to investigate different human diseases has made a remarkable contribution to the field of biomedical science. Many studies demonstrating the behavior activities of Drosophila have been studied with a motion tracking system. Most of these studies have been performed by the conventional paradigm where the Drosophila is held fixed by tethering or within the limited space. In this paper, we demonstrate the Active Omnidirectional Treadmill System (AOT) which enables the physically unrestricted Drosophila to navigate infinitely in two-dimensional space with the privilege of real-time tracking. The system maintains the position of the fly at a specific position by compensating the motion of the fly by counter direction motion of the sphere. The system is capable of maintaining the position error < 1000 µm for 89.7% of the time and the angular error < 5o 80.0% of the time. The study evaluates the performance of the different feedback control system through the experimental and simulation results. The successful phototaxis experiment was conducted to validate the usability of the system. The integration of the treadmill system with other peripherals for olfactory, vision and thermal stimuli can be a powerful tool to study the longitudinal behavior of the Drosophila. Further, the integration of the system with the optical microscopic device can be used to perform the brain imaging of the walking Drosophila.
2

Testikulární degenerace u transgenního prasečího modelu Huntingtonové nemoci / Testicular Degeneration of Transgenic Porcine Model of Huntington's Disease

Skřivánková, Monika January 2022 (has links)
Huntington's disease is an autosomal dominant neurodegenerative disorder caused by an extended (≥36) CAG repeat in the huntingtin gene. Its hallmark is brain athrophy, but huntingtin is widely deposited in all tissues of the body, most notably in the brain and testes. Its pathogenic effect is conditioned by the formation of cytotoxic forms of aggregates and fragments, which occur in both brain and peripheral tissues. Testicular atrophy has been demonstrated in postmortem samples from human patients with Huntington's disease and in transgenic mouse models. We investigated reproductive decline in a large animal model of Huntington's disease. A transgenic (tgHD) minipig model was created by inserting a lentiviral vector into the genome of a pig. Vector contained a truncated form of the N terminal part of huntingtin gene. Boars of this transgenic line showed a reduced ability to produce offspring from 13 months of age. We confirmed apoptosis of seminiferous epithelial cells and Sertoli cells, and a production of morphologically damaged spermatozoa, which were unable to efficiently fertilize the oocyte under in vitro conditions. We found a reduction of mitochondrial metabolism parameters in the sperm of tgHD boars. These changes were not dependent on the age of the boars., It is directly related to the...
3

Detect and Analyze the 3-D Head Movement Patterns in Marmoset Monkeys using Wireless Tracking System

January 2015 (has links)
abstract: Head movement is a natural orienting behavior for sensing environmental events around us. Head movement is particularly important for identifying through the sense of hearing the location of an out-of-sight, rear-approaching target to avoid danger or threat. This research aims to design a portable device for detecting the head movement patterns of common marmoset monkeys in laboratory environments. Marmoset is a new-world primate species and has become increasingly popular for neuroscience research. Understanding the unique patterns of their head movements will improve its values as a new primate model for uncovering the neurobiology of natural orienting behavior. Due to their relatively small head size (5 cm in diameter) and body weight (300-500 g), the device has to meet several unique design requirements with respect to accuracy and workability. A head-mount wireless tracking system was implemented based on inertial sensors that are capable of detecting motion in the Yaw, Pitch and Roll axes. The sensors were connected to the encoding station, which transmits wirelessly the 3-axis movement data to the decoding station at the sampling rate of ~175 Hz. The decoding station relays this information to the computer for real-time display and analysis. Different tracking systems, based on the accelerometer and Inertial Measurement Unit is implemented to track the head movement pattern of the marmoset head. Using these systems, translational and rotational information of head movement are collected, and the data analysis focuses on the rotational head movement in body-constrained marmosets. Three stimulus conditions were tested: 1) Alert, 2) Idle 3) Sound only. The head movement patterns were examined when the house light was turned on and off for each stimulus. Angular velocity, angular displacement and angular acceleration were analyzed in all three axes. Fast and large head turns were observed in the Yaw axis in response to the alert stimuli and not much in the idle and sound-only stimulus conditions. Contrasting changes in speed and range of head movement were found between light-on and light-off situations. The mean peak angular displacement was 95 degrees (light on) and 55 (light off) and the mean peak angular velocity was 650 degrees/ second (light on) and 400 degrees/second (light off), respectively, in response to the alert stimuli. These results suggest that the marmoset monkeys may engage in different modes of orienting behaviors with respect to the availability of visual cues and thus the necessity of head movement. This study provides a useful tool for future studies in understanding the interplay among visual, auditory and vestibular systems during nature behavior. / Dissertation/Thesis / Masters Thesis Bioengineering 2015
4

Uso de pedras como ferramentas para obtenção de alimentos por macacos-prego selvagens (Sapajus libidinosus)

MORAES, Bárbara Lins Caldas de 26 February 2013 (has links)
Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-08-12T12:56:30Z No. of bitstreams: 1 Barbara Lins Caldas de Moraes.pdf: 1002020 bytes, checksum: 55835be7452bb5679593acd3c7c7c122 (MD5) / Made available in DSpace on 2016-08-12T12:56:30Z (GMT). No. of bitstreams: 1 Barbara Lins Caldas de Moraes.pdf: 1002020 bytes, checksum: 55835be7452bb5679593acd3c7c7c122 (MD5) Previous issue date: 2013-02-26 / Wild capuchin monkeys use stones tools to access food items that otherwise would be unavailable, as encapsulated fruits and seeds. The successful completion of this activity not only requires the selection of the suitable tool, but also the correct technique. In order to analyze if the stone tools used by the capuchin monkeys are adjusted to the type of food item consumed and if this adjustment entails variations or behavioral adaptations to accomplish the task, stone tools and techniques used by animals to process five distinct food items, were compared. The study was conducted in an area of Pernambuco’s semiarid Caatinga, located in Serra Talhada. Along 15 months, 257 sites were identified, characterized and monitored. Behaviors of using stones as tools were documented by camera traps. Accounted a ‘total of 395 stones, used as hammers to break of five food items: Syagrus oleracea, Manihot epruinosa, Pilosocereus pachycladus, Tacinga inamoena and Commiphora leptophloeos, these last three were not yet described as accessed auxiliary items by other populations of capuchin monkeys. The use of stones as tools to process the cactaceae revealed especially interested, such strategy is related to the presence of these item’s thorns. It was found also that the characteristics of food items such as hardness, size and the presence of spines influences the stone’s selection to be used as hammers. The postures adopted by the animals for activity breaks are similar to those already described in other studies, however behavioral adaptations in handling the tool are performed to increase its functionality. / Macacos-prego selvagens utilizam ferramentas de pedra para acessar itens alimentares que de outra forma estariam indisponíveis, como frutos encapsulados e sementes. O sucesso na realização desta atividade requer não só a seleção da ferramenta adequada, mas também a correta aplicação da técnica. A fim de analisar se as ferramentas de pedras utilizadas por macacos-prego são ajustadas de acordo com o tipo de item alimentar consumido e se esse ajuste acarreta variações ou adequações comportamentais para a realização da tarefa, ferramentas de pedras e técnicas aplicadas pelos animais, para o processamento de cinco itens alimentares distintos, foram comparadas. O estudo foi realizado em uma área de Caatinga no semiárido Pernambucano, localizada no município de Serra Talhada. Ao longo de 15 meses, 257 sítios de quebra foram identificados, caracterizados e monitorados. Comportamentos de uso de pedras como ferramentas foram documentados através de armadilhas fotográficas. Contabilizamos um total de 395 pedras utilizadas como martelos para a quebra de cinco itens alimentares: Syagrus oleracea, Manihot epruinosa, Pilosocereus pachycladus, Tacinga inamoena e Commiphora leptophloeos, estes três últimos ainda não descritos como itens acessados com o auxílio de ferramentas por outras populações de macacos-prego. O uso de pedras como ferramentas para o processamento das cactáceas revelou-se especialmente interessante, pois tal estratégia está relacionada à presença de espinhos destes itens. Fatores como a distribuição e o tamanho do item alimentar parecem influenciar nas escolhas feitas pelos animais no uso das bigornas. Constatou-se, também, que características dos itens alimentares como rigidez, tamanho e presença de espinhos influenciam na seleção das pedras utilizadas como martelos. As posturas adotadas pelos animais para a atividade de quebra são semelhantes às já descritas em outros estudos, mas adequações comportamentais na manipulação da ferramenta são realizadas para aumentar a sua funcionalidade.
5

Investigating the Potential of Circular Economy in Stockholm’s Craft Classes : A Case Study Comparing Secondary Wood to Virgin Wood Using LCA and LCC

Smolic, Magdalena, Haji, Zin January 2023 (has links)
This thesis evaluates the environmental, economic, and social impacts of implementing secondary wood from recycling centers into wood crafts in Stockholm schools. The thesis is conducted in a case study setting as a part of the "Climate Neutral Stockholm 2030" sub-project 3.2, which focuses on promoting reuse and waste reduction through circularity. A comparative consequential life cycle assessment (LCA) and life cycle cost (LCC) within a cradle-to-gate system boundary was conducted in a scenario setting, which compared and quantified the use of virgin wood and secondary wood both environmentally and economically. The environmental profile was quantified for four impact categories: global warming potential (GWP), water use, land use, and cumulative energy demand (CED). Additionally, the social implications of incorporating secondary wood were examined through a survey and interviews with the wood craft teacher and students. Furthermore, the LCA and LCC were conducted with a functional unit (FU) of 0,00106 m3 of wood demand per student. The impacts were aggregated to understand the combined effect of all schools in Stockholm, from grades 3 to 9. The study's results verify that secondary wood is more environmentally and economically beneficial while also being positively perceived by the teacher and students. The environmental findings indicate a total yearly reduction in GWP by 78%, water use by 82%, land use by 99%, and CED by 90% for all schools in Stockholm. From an economic perspective, implementing secondary wood in craft classes leads to a significant cost saving of 81%. From a social aspect, results revealed an overall positive perception from the teacher and students. However, the quality and quantity of wood must be sufficient without excessive additional time or labor requirements. Furthermore, a sensitivity analysis was performed for both LCA and LCC results. It was observed that a percentage change in transportation distance does not significantly change the GWP results. In addition, secondary wooden boxes can become more expensive than virgin wooden boxes if transportation costs are increased by more than 54%. To support the "Climate Neutral Stockholm 2030" project, the study contributes to the city's pursuit of sustainability by showing decision makers the magnitude of impacts that can be reduced through circularity and waste reduction, therefore facilitating and motivating the implementation of a sustainable system in Stockholm. / Detta examensarbete syftar till att utvärdera de miljömässiga, ekonomiska och sociala effekterna av att implementera sekundärt trä, från återvinningscentraler, till träslöjden i Stockholms skolor. Examensarbetet genomförs som en fallstudie inom ramen för delprojektet 3.2 i "Klimatneutrala Stockholm 2030", som fokuserar på främjande av återanvändning och avfallshantering genom cirkularitet. En jämförande konsekvensbaserad livscykelanalys (LCA) och analys av livscykelkostnader (LCC) inom en “vagga-till-port" systemavgränsning genomfördes. Där användningen av nytt trä och sekundärträ jämfördes och kvantifierades både ur miljömässig och ekonomisk synvinkel. Den miljömässiga profilen kvantifierades för fyra effektkategorier: global uppvärmningspotential, vattenanvändning, markanvändning och kumulativ energiförbrukning. Dessutom undersöktes de sociala uppfattningarna av att införa sekundärt trä i skolorna genom en enkät och intervjuer med både eleverna och träslöjdsläraren. En LCA och LCC genomfördes med en funktionell enhet på 0,00106 m3 virkesbehov per elev. Effekterna sammanställdes för att förstå den kombinerade effekten av alla skolor i Stockholm, från årskurs 3 till 9. Resultaten av studien bekräftar att sekundärt trä är mer fördelaktigt både ur miljö- och ekonomisk synvinkel, samtidigt som det uppfattas positivt av läraren och eleverna. De miljömässiga resultaten visar en total årlig minskning av GWP med 78%, vattenanvändning med 82%, markanvändning med 99% och CED med 90% för alla skolor i Stockholm. Ur ett ekonomiskt perspektiv leder implementeringen av sekundärträ i träslöjden till betydande kostnadsbesparingar på 81%. Från en social aspekt visade resultaten en övergripande positiv uppfattning från både läraren och eleverna. Det är dock avgörande att kvaliteten och mängden trä är tillräcklig utan extra tid eller arbetsinsatser. Dessutom utfördes en känslighetsanalys för både LCA- och LCC-resultaten. Det observerades att en procentuell förändring i transportavståndet inte har en betydande effekt på GWP-resultaten. Däremot, kan en trälåda av sekundärt trä bli dyrare än en med nytt trä, om transportkostnaderna ökar med mer än 54%. För att stödja projektet "Klimatneutralt Stockholm 2030" bidrar denna studie till stadens strävan ett uppnå hållbarhet genom att visa beslutsfattare hur stor påverkan som kan uppnås genom cirkularitet och avfallsminskning. Den grunden kan underlätta och motivera implementeringen av ett hållbart system i Stockholm.

Page generated in 0.0548 seconds