The semicircular canals are involved in the coding of angular acceleration of the head and body. Presently, video-nystagmography (VNG) and specifically, caloric testing, is the gold standard for evaluation of semicircular canal function. Caloric irrigation via VNG can only evaluate horizontal semicircular canal function; with this test, there is no way to evaluate the function of the anterior and posterior vertical semicircular canals. The video Head Impulse Test (vHIT) is a relatively new protocol that has the capability to test the function of the horizontal, anterior vertical, and posterior vertical semicircular canals. Because the vHIT system is newly available to clinicians, there is a need to collect normative data, particularly for the vertical semicircular canals. For this study, data was collected from 12 participants with no complaint or history of balance difficulty. Additionally, we compared our data with normative data collected in an earlier study to determine consistency. Lateral average velocity gain measurements were consistent however, a comparison of RALP an LARP velocity gain measurements showed inconsistency.

Conventional gas turbine combustors operate with a designed drop in pressure over the length of the device. This is desired in order to encourage mixing within the combustor. Compared to this, pulse pressure gain combustors are an alternative to the conventional combustor that produces an increase in static pressure between the inlet and exhaust of the device. The removal of the combustor pressure loss increases the efficiency of the combustion process by increasing the amount of work produced. Many types of pulsed pressure gain combustors exist. Of these, the valveless pulse combustor is the simplest featuring no moving parts. Whilst some research has been conducted into investigating the performance and workings of a pulse combustor, little has been conducted with the view of cooling the combustor. This has been the focus for the research contained herein. The research has focussed on establishing an understanding of the heat transfer characteristics within a pulse combustor tailpipe. This has involved experimental, analytical and computational research on a pulse combustor as well as on a cold-flow model of a pulse combustor tailpipe. This has enabled a study into the feasibility of cooling a pulse combustor to be conducted. The research has found that for conditions where the unsteady velocity amplitude within the cold-flow model of the pulse combustor tailpipe exceeds the mean velocity, an enhancement to the heat transfer coefficient is measured compared to the value expected in a similar non-oscillating flow. When there is no enhancement to the heat transfer coefficient, the cyclic variation of the unsteady heat flux follows the variation of the unsteady pressure within the device. However, at times of enhancement, the instantaneous heat flux structure shows a large deviation from the structure of the pressure field driving the oscillations. This change is shown to be caused by the reversal in the near-wall velocity and may indicate a mechanism for the enhancement in the mean heat flux. The cooling feasibility study showed that with further investigation, it may be possible to cool a pulse combustor within a gas turbine engine.

AFRIKAANS: In hierdie studie is die rol van massa-toename in die vroeë-adolessente dogter se belewenis van die self bestudeer. Aspekte uit die literatuur wat ’n betekenisvolle bydrae tot die grondslag van die studie gelê het, is die volgende: • die rol wat massa speel in die vroeë-adolessente dogter se belewenis van die self en die implikasies daarvan op haar kledinggedrag • die rol van ander in die vroeë-adolessente dogter se belewenis van die self en die implikasies daarvan op haar kledinggedrag • die strategieë wat die vroeë-adolessente dogter gebruik om die self in hierdie ontwikkelingsfase te kan handhaaf en die implikasies daarvan op haar kledinggedrag. Die steekproef is saamgestel uit 16 blanke vroeë-adolessente dogters tussen die ouderdom van 11 en 13 jaar, wat in ’n stedelike gebied woonagtig was. ’n Kwalitatiewe navorsingsmetodologie is vir die studie gevolg met ongestruktureerde onderhoude, fokusgroepe en persoonlike dokumentasie wat ook verskeie stimulustegnieke ingesluit het. Verbatim transkripsies van die onderhoude sowel as bekrywings van die onderhoudsituasies is gebruik vir die bespreking en interpretasie van die resultate. Dit is gedoen met inagneming van die breë navorsingsvrae wat die studie gerig het. Vroeë-adolessente dogters ervaar massa-toename verskillend: • Die normale-massa vroeë-adolessente dogter ervaar dat sy deur die fase van ingrypende veranderinge, wat massa-toename insluit, eintlik vet word. Sy is konstant besig met selfmonitering; die self word ’n objek van evaluering. Sy ervaar die emosie van skaamte en poog om haar liggaam te bedek vir ander wat haar voortdurend dophou. • Aan die ander kant beleef die oormassa vroeë-adolessente dogter die ontwikkelingsfase meer ontspanne en is sy nie so bewus van haar liggaam en dit wat ander daarvan sê nie. Sy gee voor om nie so begaan te wees oor die oormassa nie, deur ander te blameer vir die situasie en vir haar voorkoms. Sy blameer selfs vir God dat Hy haar so geskep het. Sy ervaar die emosie van hartseer en deur voor te gee dat sy nie oor die situasie bekommerd is nie, hanteer sy slegs die emosie en nie die situasie nie. • Aan die einde blyk dit egter dat normale-massa en oormassa vroeë-adolessente dogters dieselfde belewenis van die self in die oorgangsfase het. Hulle voel hartseer oor die verlore kinderjare en ervaar dat hulle minder tyd het om te speel maar meer verantwoordelikhede moet dra. Die studie het die volgende bydrae gelewer: • ’n Lewensverloop- en simboliese interaksionistiese perspektief kan as geskik beskou word vir ’n studie waarin ’n ontwikkelingsfase soos vroeë adolessensie ter sprake kom. • Dit blyk dat die vroeë-adolessente dogter in die studie werklik bekommerd is oor haar voorkoms en dit wat ander van haar dink. • Dit blyk ook dat die vroeë-adolessente dogter in hierdie studie, kleding gebruik om haar voorkoms so te bestuur dat dit aan die norm van ideale liggaamsbou wat in die media voorgehou word, kan voldoen, en dat dit haar kan ondersteun in die aanneem van ‘n volwasse vroulike geslagsrol. • Dit blyk dat die normale-massa vroeë-adolessente dogter van probleem-gefokusde handhawingstrategieë gebruik maak soos bedek, wegsteek of self-manipulering van die liggaam. • Die oormassa vroeë-adolessente dogter daarenteë maak van meer emosioneel gefokusde handhawingstrategieë gebruik soos ontkenning, vermyding, kognitiewe her-ontwerp en godsdiens. Die volgende aanbevelings kan gemaak word: • Die kwalitatiewe navorsingstyl kan meer dikwels gebruik word in studies met jonger deelnemers. • Kledingkundiges behoort dit in gedagte te hou dat veral die pas van klere vir die vroeë-adolessente dogter belangrik is en dat kleding wat die liggaam ontbloot, of styf aan die liggaam pas, die liggaam benadruk en die dogter ongemaklik en skaam laat voel. • Daar behoort ook begrip te wees vir die feit dat dit vir die vroeë-adolessente dogter nou belangrik is om met verskillende voorkomsstyle te eksperimenteer ten einde ‘n voorkoms te vind wat nie net by haar veranderde liggaam pas nie, maar ook by die nuwe rol wat sy nou moet aanneem. Daar moet in gedagte gehou word dat die studie uitgevoer is met ’n beperkte aantal deelnemers en daarom kan die gevolgtrekking nie na die breë populasie veralgemeen word nie; dit het slegs betrekking op die 16 deelnemers wat met die toestemming van hul ouers aan die studie deelgeneem het. ENGLISH: In this study the role of weight gain in the early-adolescent girl’s experience of the self was studied. Aspects from the literature that were significant and formed the foundation of the study were: • the role that weight gain plays in the early adolescent girl’s perception of the self and the implication that it may have for her clothing behaviour • the role of others in the early adolescent girl’s perception of the self and the implications that it may have for her clothing behaviour • the strategies that the early-adolescent uses to cope with this development phase and the implications that it may have for her clothing behaviour The study comprises 16 white early-adolescent girls aged between 11 and 13 years who, according to acknowledged criteria, are staying in an urban environment. A qualitative research methodology was selected with unstructured interviews, focus groups, and personal documentation utilising various stimulus techniques. Verbatim transcriptions of the interviews as well as descriptions of the interview situation were used for the discussions and interpretations of the results, taking into account the broad research questions set for the study. The findings were the following: Early-adolescent girls experience weight gain differently: • The normal-weight early-adolescent girl experiences that by going through this phase of rapid change, which includes an increase in her weight, that she is actually becoming fat. She is constantly busy with self monitoring; her self is becoming an object to evaluate. She experiences the emotion of shame and wants to cover her body from people that are constantly looking at her. • On the other hand, the overweight early-adolescent girl’s experience of this phase is more relaxed; she is not so much aware of her body and what other people are saying about her. She pretends not to be worried about being overweight by blaming other people and situations for her appearance. She even blames God for creating her that way. She experiences the emotion of sadness and by pretending not to worry or by avoiding the situation, she only copes with the emotion – but the situation is not handled. • In the end it seems that normal-weight and overweight early-adolescent girls share the same experience of the self. They feel sad about losing their childhood years when they felt less ashamed and had fewer concerns about their body’s appearance. They feel the loss of having less time to play and more responsibilities. The study could make the following contribution to the theory of clothing: • The life course and symbolic interactions perspective would be suitable for studies into a developmental stage such as early adolescence. • It seems that the early-adolescent girl in this study was really concerned with her appearance and about what other people thought of her. • It seems that the early adolescent girl in this study used clothes in appearance management to manipulate her appearance in order to try and fit the ideal body that the mass media hold up as an example as well as for support in her adoption of an adult gender role. • The normal-weight early-adolescent girls in this study made use of problem-focused coping strategies such as hiding and self-manipulation of their bodies. • The overweight early-adolescent girl, on the other hand, made use of more emotionally focused coping strategies such as avoidance, re-appraisal, denial and religion. The following recommendations were made: • The qualitative research methodology could be used more often when studying younger participants. • The early adolescent girl is especially concerned about the fit of her clothes. Tight fitted clothes and clothes that expose her body make her feel uncomfortable and ashamed of herself. • An understanding of the early-adolescent girl’s need to experiment with new styles and various appearances is needed. One should keep in mind that this study was conducted with a limited number of participants and the conclusions reached therefore pertain only to the 16 participants who gave their valuable input willingly and with the consent of their parents. / Thesis (PhD)--University of Pretoria, 2009. / Consumer Science / unrestricted

With increased demand for bandwidth-hungry applications such as video-on-demand, wavelength-division-multiplexing passive optical network (WDM-PON) has become a strong contender in overcoming the last mile bottle neck. However, the wide-scale deployment of WDM-PONs has been delayed mainly due to the high cost of wavelength-specific optical components. To realize cost-effective WDM-PONs, various wavelength-independent, so called colorless architectures, have been developed so that all the subscribers can have identical optical network units (ONUs). In such WDM-PONs, however, single-fiber bidirectional transmission results in degradation of system performance caused by interference between the signals and backreflections. This thesis investigates the impact of backreflections on single-fiber bidirectional WDM-PONs. A WDM-PON with various optical line terminals (OLTs) and colorless ONU configurations is presented. The dependence of the power penalty, caused by backreflections, on a variety of parameters is investigated. This includes parameters such as the source linewidths, receiver bandwidth, transmission line loss (TLL), ONU gain, chirp effect at the ONU and optical return loss (ORL), in various WDM-PON configurations. The WDM-PON with continuous wave (CW) seed light and remodulation schemes are both presented and studied experimentally. The impacts of the backreflections on the single-fiber bidirectional WDM-PON with various OLT and ONU configurations are compared and analyzed accordingly.

It has been shown that post-menarcheal girls are more likely to have increased their body weight and body mass index (BMI) than pre-menarcheal girls of the same age. In addition to the metabolic changes which occur during this interval, behavioural risk factors synergize to promote weight gain, putting adolescents at a much higher risk for excess weight gain and its associated health complications. Moreover, obesity during adolescence increase the risk of becoming an obese adult. A systematic review of English and French articles using MEDLINE, EMBASE, Cochrane, and CINAHL was conducted. Studies underwent a three level screening assessment by two independent assessors. Only studies with post-menarcheal weight change information were selected for data extraction and quality assessment, which was conducted by two independent reviewers. A meta-analysis was conducted for weight change and included 389 girls. Five studies discussed the effects of menarche on body weight change. Pooled results for three studies indicated a 10.39 kg increase from pre to post-menarche (95% CI, 9.16-11.62). The other two studies showed significant increases in body fat mass (p<0.05) and higher skinfolds measurements for post-menarcheal girls compared to pre-menarcheal girls. It is important to further explore the bio-psychosocial and environmental factors influencing the weight, especially the total fat mass and body fat distributions in young adolescent girls during the menarche transition in order to develop and evaluate preventive intervention strategies to prevent adolescent and adult obesity.

Sensory neurons assemble to form networks that process inputs coming from the senses. Through synaptic connections neurons interact and create complex dynamical states in response to these inputs. Networks with different connectivity patterns are thought to display different states and therefore subserve different computational goals. In this thesis, we mainly study brain rhythms, a dynamical state that occurs in various neural structures. Rhythms are emergent oscillations that typically occur in homogeneous recurrent networks, whose neurons have identical properties and are densely interconnected. Many sensory systems comprise neurons with opposite ON and OFF responses to inputs. We show that homogenous recurrent networks fail to sustain rhythms when ON and OFF neurons are present in equal proportions. This happens even when the network is subjected to spatially correlated inputs, which are known to promote synchronized oscillations. In this context, we adapted the so-called linear response theory to include networks containing ON and OFF neurons with different intrinsic properties. In this asymmetric case, oscillations can be recovered. A simpler approach is to segregate the ON and OFF populations, thus producing two oscillating subnetworks. The dynamics of purely feedforward networks are studied next. These networks are composed of two or more populations. The populations are connected in a serial fashion, but neurons are unconnected within the populations. This connectivity scheme is drastically different from the fully recurrent network. Yet, this network is shown to display oscillatorylike properties when subjected to spatially correlated stimulation under certain conditions. We also find that this network can implement various types of gain control, depending on the noise in the system and the strength of synaptic interactions. These results establish some unexpected links between feedforward and recurrent networks. Along the way, we apply our results and conclusions to a well-characterized sensory network, the electrosensory system of weakly electric fish.

The purpose of this paper is to show the integration of the transmission gain values of a telemetry transmission antenna according to its relative position and integrate them in the C band link budget, in order to obtain an accuracy vision of the link. Once our C band link budget was fully performed to model our link and ready to work in real time with several received values (GPS position, roll, pitch and yaw) from the aircraft and other values from the Ground System (azimuth and elevation of the reception telemetry antenna), it was necessary to avoid a constant value of the transmitter antenna and estimate its values with better accuracy depending of the relative beam angles between the transmitter antenna and receiver antenna. Keeping in mind an aircraft is not a static telecommunication system it was necessary to have a real time value of the transmission gain. In this paper, we will show how to perform a real time link budget (C band).

No description available.

ackground: The changes in body composition markers (weight, fat mass, lean mass, and BMI) over time can be associated with TB treatment outcome among HIV-infected patients. The aim of this study was to investigate whether changes in fat mass and lean mass were associated with the treatment response among patients with HIV infection and pulmonary tuberculosis. Materials and Methods: This was a prospective cohort study. Data from HIV-infected patients commencing TB therapy were analyzed. This included body weight measurement using bioimpedance equipment at baseline, one month, and two months after starting TB treatment. Results: The study was conducted in 125 patients, 17 patients (13.6%) died during treatment, of which 5 died during the first month of treatment, 4 during the second month and 8 after the second month. The group of patients with good response, increased their weight by 1.3 kg (p <0.001) at the end of the first month of TB treatment and 2.6 kg in the second month (p <0.001), and body fat increase was 1.2 Kg (p <0.001) and 2.3 kg (p <0.001), the first and second month respectively. The group of patients who died had lost 2.1 kg fat mass after the first month (p <0.001) and 3.7 kg in the second month (p <0.001). Conclusions: Our results show that the weight change during TB treatment (increased fat mass) helps us predict therapeutic response. Weight loss during the first month of starting therapy should be evaluated thoroughly to identify the probable cause of treatment failure. / Revisión por pares

Issues surrounding the contextual environment in which strategic decisions are made are difficult concepts to grasp, particularly for undergraduate students with little business experience. They are also problematic for graduate students that have not been called on to make such decisions within their career. The authors propose an exercise that blends many elements of decision making under uncertainty and risk. Students are placed in an environment in which their own choice may differ from that of the team, but in which the team's performance will have explicit implications on their individual performance and rewards. The exercise incorporates team dynamics and problem-solving capabilities in a temporally and competitively constrained environment.