• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 396
  • 88
  • 68
  • 46
  • 40
  • 31
  • 22
  • 17
  • 8
  • 7
  • 7
  • 5
  • 5
  • 5
  • 4
  • Tagged with
  • 866
  • 139
  • 82
  • 67
  • 66
  • 65
  • 61
  • 58
  • 55
  • 54
  • 53
  • 42
  • 41
  • 41
  • 40
  • 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.
251

Hydrodynamics of Binary Bose-Einstein Condensates and Hydro-elasticity of the Inner Crust of Neutron Stars

Kobyakov, Dmitry January 2014 (has links)
In the present thesis, “Hydrodynamics of Binary Bose-Einstein Condensates and Hydro-elasticity of the Inner Crust of Neutron Stars”, the hydrodynamic effects, instabilities and superfluid turbulence in binary immiscible ultracold gases, and hydro-elastic macroscopic coupled modes and microscopic structure of the inner layers of the crust of neutron stars, are studied. The ultracold gas dynamics can be realized in the laboratory. The excitation modes of the inner crust determine a number of observable properties such as elasticity, thermal properties and mass transport properties. Here we focus on expanding the details, rather than repeating the results presented in the published articles. In the part of the thesis related to atomic ultracold gases, we utilize the physical parameters in the experimentally realizable parameter region. We numerically simulate the coupled non-linear Schrödinger equations, and calculate observable quantities, such as phase and modulus of the order parameter, conditions needed for observation of the Rayleigh-Taylor instability and for turbulence generation. The numerical calculations are accompanied by analytical description of the processes. The dispersion relation for capillary-gravitational waves at the interface between two ultracold gases, is derived straightforwardly from the superfluid Lagrangian. The equations of motion for centre-of-mass of the superfluids are derived, and then used in our model of the quantum swapping of immiscible superfluids pressed by a strong external force. By numerical simulation, we find that the Kelvin-Helmholtz instability which occurs at the non-linear stage of the Rayleigh-Taylor instability, can generate quantum turbulence with peculiar properties. We find that two-dimensional superfluid systems with weak inter-component repulsion are different from previously studied strongly repulsive binary superfluids, because the quantum Kelvin-Helmholtz instability in weakly repulsive superfluids rolls up the whole interface forming a vortex bundle, similarly to dynamics of the shear fluid layers in the classical hydrodynamics. Production of vortex bundles favours the Kolmogorov spectrum of turbulence, and we find that the Kolmogorov scaling indeed is present in a freely decaying turbulence. In the part of the thesis related to neutron stars, we study the inner crust of neutron stars, where the fully ionized atomic nuclei coexist with a superfluid of neutrons. The interaction between superfluid neutrons and the crystallized Coulomb plasma is due to the interaction between density perturbations (interaction of the scalar type), and between the current - the non-dissipative entrainment effect (interaction of the vector type). We calculate velocities of the collective modes of the crystal coupled to superfluid neutrons. As an input we use the results of microscopic nuclear calculations in the framework of the compressible liquid drop model (the Lattimer and Swesty equation of state), and more recent effective Thomas-Fermi calculations with shell corrections (N. Chamel, and the Brussels theoretical nuclear physics group). Knowledge of velocities as functions of the matter density in the inner crust is important for calculation of a number of dynamic and transport properties. The heat transport properties of the inner crust are directly observable in accreting binary systems (low-mass x-ray binaries). The mass transport properties of the inner crust are directly linked to the rotational evolution, being a key physical ingredient of the pulsar glitch phenomenon. The elastic properties are related to the vibrational modes of the star, and to the breaking stress of the crust. In the second part of our work on neutron stars we investigate the microscopic structure of the inner crust treating the structure as an anisotropic crystal coupled to s-wave superfluid neutron liquid. As we analyse dynamics of the elementary excitations at higher wavenumbers (smaller scales), we reach the edge of the first Brillouin zone. The Lattimer-Swesty data is applicable for wavenumbers much smaller than the edge of the first Brillouin zone. We extrapolate the data through the whole first Brillouin zone to calculate the fastest growth rate of the unstable modes. The crucial step is to calculate the mode velocities in anisotropic crystal incorporating both the induced neutron-proton interactions, and the electron screening properties. We find that the combined influence of these two effects leads to softening of the longitudinal phonon of the lattice above about the Thomas-Fermi screening wavenumber of the electrons. The critical wavenumber when the frequency becomes purely imaginary is about  1/5 - 2/3  of the reciprocal lattice vector, thus validating our assumption. The imaginary mode frequency implies instability at finite wavenumbers. Our calculations suggest that the mode at the first Brillouin zone edge is the most unstable, and thus the structure experiences a displacive phase transition when the central ion of a unit cell of the body-cubic-centred lattice, is displaced to the cube face. Thus, the electronic structure of matter at densities above the neutron drip [1], is richer than previously appreciated, and new microscopic calculations of nuclear structure are necessary which take into account the high-wavenumber physics. Such calculations will provide crucial input to models interpreting the quasi-periodic oscillations in Soft Gamma Repeaters as magnetar x-ray flares, and to the theory of glitches of neutron stars. [1] The neutron drip density is ~3×1011 g cm-3.
252

Inner strength among old people : a resource for experience of health, despite disease and adversities

Viglund, Kerstin January 2013 (has links)
Background Inner strength has been described as an important phenomenon in association with disease management, health, and ageing. To increase the knowledge of the phenomenon of inner strength, a meta-theoretical analysis was performed which resulted in a model of Inner Strength where inner strength comprises four interrelated and interacting dimensions; connectedness, creativity, flexibility, and firmness. The model was used in this thesis as a theoretical framework. Aim The overall purpose of this thesis was to develop and validate an inner strength scale, describe inner strength among an older population, and elucidate its significance for experience of health, despite disease and adversities. Methods The studies had quantitative approaches with cross-sectional designs (I-III) and a qualitative approach with narrative interviews (IV). Studies I-IV was part of the GErontological Regional DAtabase (GERDA) Botnia project. In study I, the participants (n = 391, 19-90 years old) were mostly from northern Sweden. In studies II and III, the participants (n = 6119, 65, 70, 75 and 80 years old) were from Sweden and Finland, and in study IV the participants (n = 12, 67-82 years old) were from Västerbotten County. Data was analysed using principal component analysis and confirmatory factor analysis (CFA), various statistics, structural equation modelling, and qualitative content analysis. Results In study I, the Inner Strength Scale (ISS) was developed and psychometrically tested. An initial 63-item ISS was reduced to a final 20-item ISS. A four-factor solution based on the four dimensions of inner strength was supported, explaining 51% of the variance, and the CFA showed satisfactory goodness-of-fit. In study II, ISS scores in relation to age, gender and culture showed the highest mean ISS score among the 65-year-olds, with a decrease in mean score for every subsequent age (70, 75, and 80 years). Women had slightly higher mean ISS scores than men, and there were minor differences between the regions in Sweden and Finland. In study III, a hypothesis was proposed and subsequently supported in the results where inner strength was found to partially mediate in the relationship between disease and self-rated health. The bias-corrected bootstrap, estimating the mediating indirect effect was significant and the test of goodness-of-fit was satisfactory. In study IV, from the narratives of inner strength it was found that inner strength comprised feelings of being connected and finding life worth living. Having faith in oneself and one’s possibilities and facing and taking an active part in the situation were also expressed. Finally, coming back and finding ways to go forward in life were found to be essential aspects of inner strength. Conclusions The newly developed ISS is a reliable and valid instrument that captures a broad perspective of inner strength. Basic data about inner strength in a large population of old people in Sweden and Finland is provided, showing the highest mean ISS score among the 65-year-olds. Inner strength among old people is a resource for experience of health, despite disease and adversities. This thesis contributes to increase knowledge of the phenomenon of inner strength and provide evidence for the importance of inner strength for old people’s wellbeing. Increased knowledge of the four dimensions of inner strength; connectedness, creativity, flexibility and firmness, is proposed to serve as an aid for health care professionals in their efforts to identify where the need of support is greatest and to find interventions that promotes and strengthen inner strength. / Bakgrund Inre styrka har beskrivits som ett viktigt fenomen associerat till att hantera sjukdom, till hälsa och åldrande. För att öka kunskapen om fenomenet inre styrka genomfördes en metateoretisk analys som resulterade i en Inre Styrka modell där inre styrka omfattar fyra samverkande dimensioner; samhörighet, kreativitet, flexibilitet och fasthet. Modellen har använts i denna avhandling som ett teoretiskt ramverk. Syfte Det övergripande syftet med denna avhandling var att utveckla och testa en skala som mäter inre styrka, beskriva inre styrka i en population av äldre, och att belysa dess betydelse för upplevelsen av hälsa, trots sjukdom 0ch motgångar. Metod Studierna som genomfördes hade kvantitativ ansats med tvärsnittsdesign (I-III) och kvalitativ ansats med narrativa intervjuer (IV).  Alla studier var en del av GErontologiska Regionala DAtabas (GERDA) Botnia projektet. Deltagarna i studie I (n= 391, 19-90 år) var mestadels från norra delarna av Sverige. I studierna II och III var deltagarna (n=6119, 65, 70, 75 och 80 år) från Sverige och Finland. I studie IV var deltagarna (n=12, 67-82 år) från Västerbotten. Data analyserades med hjälp av principalkomponentanalys och konfirmatorisk faktor analys (CFA), varierande statistik, strukturell ekvationsmodellering, och kvalitativ innehållsanalys. Resultat I studie I utvecklades och testades Inre Styrka Skalan (ISS). En inledande 63 frågors ISS reducerades till en slutlig 20 frågors ISS. Baserad på de fyra dimensionerna av inre styrka bekräftades en fyrafaktors lösning med 51 % förklaringsgrad och CFA visade ett tillfredställande goodness-of-fit. I studie II beskrevs inre styrka i relation till ålder, kön och kultur. Det högsta totala ISS medelvärdet skattades bland 65-åringarna med lägre medelvärden för varje efterföljande ålder (70, 75 och 80 år). Kvinnor skattade ett något högre totalt ISS medelvärde än män och det var inte några större skillnader mellan regionerna i Sverige och Finland. I studie III bekräftades den hypotes som lagts fram, att inre styrka kan mediera i relationen mellan sjukdom och upplevelsen av hälsa. Bias-corrected bootstrap visade en signifikant indirekt effekt i relationen mellan sjukdom och upplevelsen av hälsa, medierad av inre styrka, och test av modellens goodness-of-fit var tillfredsställande. I studie IV, utifrån berättelserna om inre styrka visade det sig att inre styrka omfattar känslor av samhörighet och att finna livet värt att leva. Att ha tillit till sig själv och sina möjligheter, och att kunna möta och ta aktiv del i situationen beskrevs också. Slutligen, att komma igen och hitta vägar att gå vidare i livet var viktiga aspekter av inre styrka.  Slutsatser Den nyutvecklade Inre Styrka Skalan är ett reliabelt och valitt instrument som fångar ett brett perspektiv av inre styrka. Basdata om inre styrka i en stor population äldre i Sverige och Finland har presenterats, och visar det högsta ISS medelvärdet bland 65-åringarna. Inre styrka bland äldre är en resurs för upplevelsen av hälsa, trots sjukdom och motgångar. Denna avhandling bidrar till att öka kunskapen om fenomenet inre styrka och ger evidens för att inre styrka har en viktig betydelse för äldres välbefinnande. Ökad kunskap om de fyra dimensionerna av inre styrka; samhörighet, kreativitet, flexibilitet, och fasthet, föreslås kunna vara en hjälp för vårdpersonal i deras arbete att identifiera var behovet av stöd är störst och att sätta in insatser som främjar och stärker inre styrka. / GErontologiska Regionala DAtabas (GERDA) Botnia projektet
253

Moksleivių vidinės darnos, psichosocialinės aplinkos ir sveikatos nusiskundimų sąsajų tyrimas / Associations between sense of coherence, psychosocial environment and health complaints among students

Kirtiklytė, Kristina 16 June 2008 (has links)
Darbo tikslas. Įvertinti moksleivių vidinės darnos, psichosocialinės aplinkos ir sveikatos nusiskundimų sąsajas. Tyrimo metodika. Tyrime dalyvavo 291 Kauno X vidurinės mokyklos 5 – 12 klasių moksleiviai (atsako dažnis 67,8 proc.). Tyrimas atliktas 2007 m. lapkričio – 2008 m. kovo mėnesiais. Duomenys surinkti anoniminės anketinės apklausos būdu. Statistinė duomenų analizė atlikta naudojant kompiuterinį SPSS 13.0 statistinį paketą ir MS Excel. Rezultatai. Mūsų rezultatai parodė, kad 59,2 proc. apklaustų moksleivių pasižymėjo aukšta vidine darna, žema vidine darna pasižymėjo 7,0 proc. 5-9 klasių moksleivių, ir 4,1 proc. 10 - 12 klasių moksleivių. Žema vidine darna pasižymintys moksleiviai patikimai dažniau skundėsi liūdesiu (p<0,0001), nemiga (p=0,004), silpnumu (p<0,001), jautė stresą (p<0,0001), jautėsi nelaimingi (p<0,0001), palyginus su aukšta vidine darna pasižyminčiais moksleiviais. Dažną priekabiavimą (kartą per savaitę ir dažniau) patyrė 16,6 proc. moksleivių, atsitiktinį 36,9 proc. moksleivių. Žemos vidinės darnos grupėje net 43,8 proc. moksleivių patyrė dažną priekabiavimą mokykloje (p=0,003), palyginus su priekabiavimo nepatyrusiais) ir 18,8 proc. moksleivių priekabiavimą patyrė metus ir daugiau. Net 22,4 proc. moksleivių rūko arba kažkada rūkė. Kas savaitę ir dažniau alkoholį vartoja 5,9 proc. moksleivių. Didžiausia dalis moksleivių jautėsi pavargę ryte (51,7 proc.), skundėsi irzlumu (40,3 proc.) ir įtampa (31,4 proc.). Rezultatai patvirtino statistiškai reikšmingas... [toliau žr. visą tekstą] / Objective of the study. To evaluate the associations between sense of coherence, psychosocial environment and health complaints among students. Methods. The survey was conducted among Kaunas X secondary school 5 – 12 grade students from November, 2007 until March, 2008. Totally 291 students participated in the study (response rate 67.8 percent). Data collection was performed by means of anonymous questionnaire. The statistical softwares SPSS 13.0 and MS Excel. were used in the statistical analysis. Results. Our results indicated that 59.2 per cent of students had high sense of coherence, 7 percent of 5-9 grade students and 4.1 percent of 10 and 12 grade students had low sense of coherence. Sadness (p<0.0001), insomnia (p=0,004), weakness (p<0,001), stress (p<0.0001), unhappiness (p<0.0001) were more prevalent in the subgroup of low sense of coherence as compared to the high one. 16.6 percent of students experienced frequent harassment (once per week and more often), and 36.9 percent of students experienced occasional harassment. The prevalence of frequent harassment was 43.8 percent in the subgroup of low sense of coherence (p=0,003 compared to non-experienced the harassment and 18.8 per cent of students experienced harassment for one year and longer. Even 22.4 percent of students were recent or former smokers, 5.9 percent were weekly and more often alcohol users. The most prevalent health complaints were tiredness in the morning (51.7 percent), irritability (40.3 percent)... [to full text]
254

Vidaus audito įtaka Telšių apskrities vidurinių mokyklų veiklos kokybei / The inner audit influence in Telšiai District Comprehensive schools for quality of activity

Leinartienė, Lina 23 January 2009 (has links)
Magistrinio darbo tema: „Vidaus audito įtaka Telšių apskrities vidurinių mokyklų veiklos kokybei“. Darbo autorė: Lina Leinartienė. Darbo tikslas: išanalizuoti ir empiriškai pagrįsti bendrojo lavinimo mokyklos vidaus audito įtaką mokyklos veiklos kokybės gerinimui Telšių apskrities vidurinėse mokyklose. Uždaviniai: 5. Atskleisti švietimo kokybės sampratą. 6. Apibrėžti švietimo kokybės rodiklius. 7. Išanalizuoti bendrojo lavinimo mokyklos vidaus audito metodiką. 8. Nustatyti mokyklos vidaus audito įtaką mokyklos kokybei. 9. Pateikti rekomendacijas, kaip pagerinti švietimo kokybę naudojant vidaus audito rezultatus. Tyrimo objektas - Telšių apskrities vidurinių mokyklų pedagogai ir vadovai. Tyrimo dalykas - Telšių apskrities vidurinių mokyklų vadovų ir pedagogų požiūris į vidaus audito vykdymą, jo įtaką švietimo kokybei. Tyrimo hipotezė - mokyklos vidaus auditas ne visada nustato mokyklos veiklos kokybės trūkumus ir parengia tinkamas rekomendacijas tiems trūkumams šalinti. Imtis: Tyrime dalyvavo Telšių apskrities vidurinių mokyklų 270 mokytojų bei 22 mokyklų vadovai. Atlikus tyrimą Telšių apskrities vidurinėse mokyklose, nustatyta, kad mokyklos vidaus auditas ne visada nustato mokyklos veiklos kokybės trūkumus ir parengia tinkamas rekomendacijas tiems trūkumams šalinti. Pagrindinės problemos, trukdančios tinkamai atlikti vidaus auditą bendrojo lavinimo mokykloje, yra laiko bei pedagogų įgūdžių trūkumas, sudėtinga metodika, neigiamos mokytojų nuostatos į vidaus auditą. Nors... [toliau žr. visą tekstą] / The topic of master paper: „The inner audit influence in Telšiai District Comprehensive schools for quality of activity“. The author of paper: Lina Leinartienė. The aim of the paper: to analyze and justify empirically the influence of comprehensive schools’ inner audit on school activities quality‘s development in Telšiai district secondary schools. The goals: 10. To reveal conception of education quality. 11. To describe the indexes of education quality. 12. To analyze the methodology of comprehensive school‘s inner audit. 13. To establish the influence of inner audit on school‘s quality. 14. To list the recommendations how to improve education quality using the results of inner audit. The research object - Telšiai district secondary schools’ pedagogues and directors. The theme of research – the attitude of Telšiai district secondary schools’ directors and pedagogues on the implementation of inner audit and its influence on the education quality. Hypothesis of the research – the inner school‘s audit not always detects the defects of school activities’ quality and prepares the necessary recommendations to eliminate those defects. Undertake: There participated 270 teachers and 22 schools’ directors from Telšiai district secondary schools. After finishing of research in Telšiai district secondary schools there were found out that the inner school‘s audit not always detects the defects of school activities’ quality and prepares the necessary recommendations to eliminate... [to full text]
255

Auditory domain speech enhancement

Yang, Xiaofeng 04 June 2008 (has links)
Many speech enhancement algorithms suffer from musical noise - an estimation residue noise consisting of music-like varying tones. To reduce this annoying noise, some speech enhancement algorithms require post-processing. However, a lack of auditory perception theories about musical noise limits the effectiveness of musical noise reduction methods. Scientists now have some understanding of the human auditory system, thanks to the advances in hearing research across multiple disciplines - anatomy, physiology, psychology, and neurophysiology. Auditory models, such as the gammatone filter bank and the Meddis inner hair cell model, have been developed to simulate the acoustic to neuron transduction process. The auditory models generate the neuron firing signals called the cochleagram. Cochleagram analysis is a powerful tool to investigate musical noise. We use auditory perception theories in our musical noise investigations. Some auditory perception theories (e.g., volley theory and auditory scene analysis theories) suggest that speech perception is an auditory grouping process. Temporal properties of neuron firing signals, such as period and rhythm, play important roles in the grouping process. The grouping process generates a foreground speech stream, a background noise stream, and possibly additional streams. We assume that musical noise is the result of grouping to the background stream the neuron firing signals whose temporal properties are different from the ones grouped to the foreground stream. Based on this hypothesis, we believe that a musical noise reduction method should increase the probability of grouping the enhanced neuron firing signals to the foreground speech stream, or decrease the probability of grouping them into the background stream. We propose a post-processing musical noise reduction method for the auditory Wiener filter speech enhancement method, in which we employ a proposed complex gammatone filter bank for the cochlear decomposition. The results of a subjective listening test of our speech enhancement system show that the proposed musical noise reduction method is effective. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2008-05-28 16:11:28.374
256

Provision of leisure facilities towards improving the quality of life in the residential inner city : a case study of Albert park.

Dladla, Sibusiso. 27 November 2013 (has links)
In South African cities, the subdivision of the social world and spaces which the public inhabits tends to manifest and reflect itself in the leisure choices that the public makes. It has been proven that leisure choices and experiences affect an individual's mental state and experience and in addition, they superimpose a long lasting structure onto human societies. Contemporary inner city housing developments are infested with antisocial challenges which are in the form of delinquency, alcohol abuse and drug trafficking. If such challenges go by unchecked, it may lead to a totally deteriorated society and environment. The aim of this dissertation is to explore the possibility of facilitating social and economic upliftment amongst inner city youth through provision of adequate and appropriate leisure facilities and spaces. From a planning and an architectural approach, the intention is to reveal how architecture may be used to alleviate the social ills that have infested the residential inner city. It is believed that architecture and the built environment should play a role in correcting, improving and echoing the ethics and values of its users such that there is a mutual harmony and coexistence. / Thesis (M.Arch.)-University of KwaZulu-Natal, 2006.
257

Having CLOUT: becoming an ally and having the power to resist colonialism and neoliberalism in Winnipeg's inner city

O'Brien, Carole S. 26 September 2013 (has links)
Becoming an ally to Indigenous peoples, as a planner, depends on understanding the oppressive dynamics of colonialism and neoliberalism that invisibilize their everyday realities. Resisting these dynamics as an ally, and as a planner, also depends on becoming liberated from them, and to create spaces for collectivization, since only the collective has the power to resist the oppressive systems and discourses that characterize these ideologies. In Winnipeg, a coalition of Indigenous inner city community development practitioners (CLOUT) is effectively resisting these hegemonies. Contrasting this everyday resistance praxis is the practice of non-Indigenous city planners who are placated in their own everyday by the problems of difference and separation these hegemonies produce; effectively being thwarted in their ability to resist. Alliance building will remain a challenge between these two groups, that is unless the planners learn from CLOUT: become allies to each other, unlearn their euro-western way of thinking and learn the value of practices oriented towards integration, that in themselves counter the divisive nature colonialism and neoliberalism.
258

The social impacts of bed bugs on inner-city residents

Lyons, James 10 September 2010 (has links)
Bed bugs are making a large international comeback. While people from all economic and social backgrounds can experience a bed bug infestation, the social impacts on the lives of low-income people are potentially far greater given the condition of their living accommodations as well as the financial costs associated with dealing with an infestation. Utilizing the Community Economic Development and Social Determinants of Health approaches, this thesis argues that the experience of a bed bug infestation poses a significant threat to inner-city residents—economically, socially, and in terms of human health. Interviews with 16 inner-city residents, 2 landlords, 1 property manager, 2 By-Law Enforcement Officers, and 5 representatives of inner-city agencies in Winnipeg are drawn upon in developing this argument. In addition, relevant policy documents and other secondary sources are utilized to assess the effectiveness of policies and practices in place to respond to this issue and to offer a more comprehensive approach for responding to the social impacts of bed bugs in the city of Winnipeg.
259

Applications of organ culture of the mouse inner ear

Berggren, Diana January 1991 (has links)
The embryonic mouse inner ear was used as a model with which to study ototoxicity and tissue interactions. The inner ear anlage can be explanted and cultured in vitro from about the 12th gestational day (gd), and will differentiate parallel with the inner ear developing in vivo until a time corresponding to birth (21st gd). During this period the ovoid sac develops into the labyrinth. In the present thesis work, otic anlagen from gd 12, 13, 13.5, 15 and 16 were used. As a rule the explants were kept in culture until a time point equivalent to the 21st gd. Analyses using freeze-fracture technique and transmission electron microscopy showed that in cultured 13th gd otocysts the development of junctional complexes followed the same principal pattern as in vivo. Tight junctions develop into many strands lying parallel to the apical surface of all epithelial cells. Uncoupling of the hair cells occurs with loss of gap junctions. Some tight junctions had an aberrant appearence, with in part very thick strands and strands running at right angles to the apical surface. All aminoglycosides are potentially ototoxic. In the inner ear, outer hair cells of the organ of Corti and vestibular type I hair cells are affected by these antibiotics. The access route to the hair cells and the sites and mechanisms of action of aminoglycosides are not precisely defined. The uptake of tritiated tobramycin in 16th gd inner ears was studied. An initial rapid uptake of the drug, within 10 min, was followed by a slower accumulation, reaching a steady state after 60 min. Most of the tobramycin was bound reversibly, at least after a short period of incubation (2 h). The irreversibly bound fraction was of the same magnitude as the uptake within 10 min. Uptake took place against a concentration gradient. The otocyst can differentiate even without the statoacoustic ganglion. The interaction of the sensory epithelium with the ganglion was investigated by explanting the statoacoustic ganglion without target tissue. Twenty-five percent of the ganglions survived and had outgrowth of neurites but there was no differentiation into either the cochlear or vestibular type of neuron cells. Exposure of cultured otocysts (13 or 13.5 gd) to l-azetidine-2-carboxylic acid, a 1-proline analog that disrupts formation of collagen, resulted in retarded morphogenesis of the labyrinth and a dose- dependent derangement of the basal lamina. The expression of intermediate filaments (IFs) was analysed using monoclonal antibodies. The same IF pattem was found in cultured inner ears as in vivo. Explants were taken on 13th, 15th or 16th gd. Exposure to gentamicin, ethacrynic acid or cisplatin did not alter the IF composition. Cytokeratins (CKs) 8 and 18 were identified in all inner ear epithelia. In addition CKs 7 and 19 were visualized in the epithelia involved in maintaining endolymph homeostasis. The ganglion cells showed coexpression of CK, vimentin and neurofilaments. The elemental composition of the endolymph compartment of 16th gd inner ears cultured for 5 days was studied using energy-dispersive X-ray microanalysis. Na to K ratios characteristic of endolymph were found. / <p>S. 1-34: sammanfattning, s. 37-88: Härtill 6 uppsatser</p> / digitalisering@umu
260

AN INVESTIGATION OF THE REYNOLDS NUMBER DEPENDENCE OF THE NEAR-WALL PEAK IN CANONICAL WALL BOUNDED TURBULENT CHANNEL FLOW

Estejab, Bahareh 01 January 2011 (has links)
An experimental investigation into fully developed high aspect ratio channels was undertaken. A review of the literature reveals that there is a need for accurate measurement of the inner peak value of streamwise turbulence intensity despite the large number of studies already completed. The scattered data on this subject could be attributed either to insufficient channel size (aspect ratio or length) or to hot-wire spatial filtering. A new, high quality, channel flow facility was designed and constructed, considering the most recent geometric limitation provided in the literature. To obtain accurate results, data were acquired using hot-wire probes with constant viscous-scale sensing length and were corrected using the most recent correction formula proposed by Smits et al. (2011). The results show dependence of inner peak value on Reynolds number in channels flow - its magnitude increasing with increasing Reynolds number.

Page generated in 0.0559 seconds