Influence of Tire Tread Pattern and Runway Surface Condition on Braking Friction and Rolling Resistance of a Modern Aircraft Tire

A series of taxiing tests was conducted at the Langley landing loads track with both braked and unbraked (freely rolling) single and tandem wheels equipped with 32x8.8 type VII aircraft tires of different tread designs to obtain data on tire and braking characteristics during operation on dry and on contaminated concrete and asphalt run ways. Contaminants used were water, slush, JP-4 jet fuel, and organic and detergent fire-extinguishing foams. Forward velocities for the tests ranged from approximately 13 to 104 knots. Vertical loads of approximately 9,000 to 22,000 pounds and tire inflation pressures of 85 to 350 pounds per square inch were used. Results indicated that the unbraked tire rolling resistance increased with increasing forward velocity on dry and on contaminated runway surfaces. Peak tire-ground friction coefficients developed during wheel braking decreased rapidly with increasing velocity on contaminated runways but remained relatively unchanged on dry runways as the forward velocity was increased. Dry-runway friction coefficients were found to be relatively insensitive to tire tread pattern. However, the magnitude of the friction coefficients developed by tires on contaminated runways was extremely sensitive to the tire tread pat tern used, with circumferential-groove treads developing the highest values of friction coefficient, and smooth and dimple treads the lowest values for the tread patterns and runway conditions investigated

The Theology of Aeschylus.

This thesis examines the theology of Aeschylus through a close text-based discussion of the nature and justice of Zeus. This will not be a dogmatic investigation that looks for signs of monotheism or 'proto-monotheism'. Rather, this thesis will examine the presentation of the god in Aeschylus, as he is found in his plays, free from any desire or attempt to form a rounded, comprehensive 'Aeschylean theology'. The first chapter considers the two closely connected divine terms, thetaepsilonozeta and deltaalphaiotamuonu. The clear-cut and easily discernible meaning of thetaepsilonozeta acts as a constant with which the more ambiguous and less determinable word deltaalphaiotamuonu can be compared and contrasted. This chapter discusses both those instances where deltaalphaiotamuonu seems to be synonymous with thetaepsilonozeta and where it does not, where the term seems to possess a meaning close to that of an individual's fortune or destiny in life. This is done in order to conclusively see how Aeschylus uses the word deltaalphaiotamuonu in the Eumenides as part of his characterisation of the Erinyes, which enables us to see more clearly what role divine terminology plays in the presentation of Zeus and the god's justice. The remaining chapters of this thesis examine Zeus in Aeschylus. First, attention is given to the old debates concerning the potential and respective influence of Homeric, Hesiodic and Presocratic conceptions of divinity on the theology of Aeschylus. Then, the final chapter of the thesis looks at the justice of Zeus primarily through a discussion of one question, whether we should understand Agamemnon as guilty in the eyes of Zeus, which it is argued we should not. It is shown that Aeschylus does not present an optimistic idea of Zeus or divine justice, and the god's rule is seen as neither kind nor benevolent. Rather a pragmatic and pessimistic view is presented to us by Aeschylus, one which recognises that Zeus is an all-powerful being in need of respect and honour and whose will must be carefully observed

Laser cooling of a magnetically guided ultra cold atom beam

We report on the transverse laser cooling of a magnetically guided beam of ultra cold chromium atoms. Radial compression by a tapering of the guide is employed to adiabatically heat the beam. Inside the tapered section heat is extracted from the atom beam by a two-dimensional optical molasses perpendicular to it, resulting in a significant increase of atomic phase space density. A magnetic offset field is applied to prevent optical pumping to untrapped states. Our results demonstrate that by a suitable choice of the magnetic offset field, the cooling beam intensity and detuning, atom losses and longitudinal heating can be avoided. Final temperatures below 65 microkelvin have been achieved, corresponding to an increase of phase space density in the guided beam by more than a factor of 30.Comment: 9 pages, 4 figure

A qualitative study of patients and healthcare workers’ experiences and perceptions to inform a better understanding of gaps in care for pre-discharged tuberculosis patients in Cape Town, South Africa

Background Many people diagnosed with Mycobacterium tuberculosis (TB) in tertiary and district hospitals in South Africa do not arrive at their primary care clinic for continued care after they are discharged from the hospital. This loss to follow up is a major, ongoing problem for public health in South Africa, and contributes to drug-resistant TB strains. The objective of this paper was to explore patients’ experiences and perceptions of diagnosis and treatment before their discharge from hospital. We use a framework known as patient-centred care to illustrate how these patient narratives point to lapses in these principles within the hospital system, and to show how such lapses may contribute to loss to follow up and inconsistent TB care. Methods We employed a qualitative study using semi-structured interviews to investigate patient and healthcare workers’ experiences and perceptions of TB care in two Western Cape hospitals. We purposefully sampled 17 patients, 10 healthcare workers, and two key informant policy makers, all of whom had relevant experiences and insights. Data collection was done between October 2015 and February 2017. Data were analysed using Miles and Huberman’s qualitative analysis framework. Results Hospitals did not achieve patient-centred care. Newly diagnosed patients were provided with inadequate TB education, diseased-focused approaches were favoured over patient-focused approaches, and there was limited engagement with patients to understand their needs and feelings during the critical period between diagnosis and discharge. Consequently, some patients felt anxious prior to their discharge from hospital. Coupled with their overwhelming socio-economic barriers and complex family situations, some patients felt hopeless and powerless as they prepared for discharge. Finally, there was a lack of patient-provider partnership due to problems including healthcare workers’ time constraints and heavy workloads, which detracted from a focus on patients’ needs and feelings. Conclusions Improving the three intersecting elements of patient-centred care (health education, engaging with patients’ needs and feelings, and shared decision-making) has the potential to positively influence patients’ continuity of care for TB in South Africa. It would be helpful to also proactively address how patients plan to stay connected to care, on treatment, and supported, in light of their family situation or socio-economic circumstances. Detailed and unique pre-discharge counselling for each patient may be valuable in this regard

Ca analysis : an Excel based program for the analysis of intracellular calcium transients including multiple, simultaneous regression analysis

Here I present an Excel based program for the analysis of intracellular Ca transients recorded using fluorescent indicators. The program can perform all the necessary steps which convert recorded raw voltage changes into meaningful physiological information. The program performs two fundamental processes. (1) It can prepare the raw signal by several methods. (2) It can then be used to analyze the prepared data to provide information such as absolute intracellular Ca levels. Also, the rates of change of Ca can be measured using multiple, simultaneous regression analysis. I demonstrate that this program performs equally well as commercially available software, but has numerous advantages, namely creating a simplified, self-contained analysis workflow

Experiences of HIV-positive postpartum women and health workers involved with community-based antiretroviral therapy adherence clubs in Cape Town, South Africa

Background The rollout of universal, lifelong treatment for all HIV-positive pregnant and breastfeeding women (“Option B+”) has rapidly increased the number of women initiating antiretroviral treatment (ART) and requiring ART care postpartum. In a pilot project in South Africa, eligible postpartum women were offered the choice of referral to the standard of care, a local primary health care clinic, or a community-based model of differentiated ART services, the adherence club (AC). ACs have typically enrolled only non-pregnant and non-postpartum adults; postpartum women had not previously been referred directly from antenatal care. There is little evidence regarding postpartum women’s preferences for and experiences of differentiated models of care, or the capacity of this particular model to cater to their specific needs. This qualitative paper reports on feedback from both postpartum women and health workers who care for them on their respective experiences of the AC. Methods One-on-one in-depth qualitative interviews were conducted with 19 (23%) of the 84 postpartum women who selected the AC and were retained at approximately 12 months postpartum, and 9 health workers who staff the AC. Data were transcribed and thematically analysed using NVivo 11. Results Postpartum women’s inclusion in the AC was acceptable for both participants and health workers. Health workers were welcoming of postpartum women but expressed concerns about prospects for longer term adherence and retention, and raised logistical issues they felt might compromise trust with AC members in general. Conclusions Enrolling postpartum women in mixed groups with the general adult population is feasible and acceptable. Preliminary recommendations are offered and may assist in supporting the specific needs of postpartum women transitioning from antenatal ART care. Trial registration Number NCT02417675 clinicaltrials.gov/ct2/show/record/NCT02417675 (retrospective reg.

Peptide location fingerprinting reveals tissue region-specific differences in protein structures in an ageing human organ

In ageing tissues, long-lived extracellular matrix (ECM) proteins are susceptible to the accumulation of structural damage due to diverse mechanisms including glycation, oxidation and protease cleavage. Peptide location fingerprinting (PLF) is a new mass spectrometry (MS) analysis technique capable of identifying proteins exhibiting structural differences in complex proteomes. PLF applied to published young and aged intervertebral disc (IVD) MS datasets (posterior, lateral and anterior regions of the annulus fibrosus) identified 268 proteins with age-associated structural differences. For several ECM assemblies (collagens I, II and V and aggrecan), these differences were markedly conserved between degeneration-prone (posterior and lateral) and -resistant (anterior) regions. Significant differences in peptide yields, observed within collagen I alpha 2, collagen II alpha 1 and collagen V alpha 1, were located within their triple-helical regions and/or cleaved C-terminal propeptides, indicating potential accumulation of damage and impaired maintenance. Several proteins (collagen V alpha 1, collagen II alpha 1 and aggrecan) also exhibited tissue region (lateral)-specific differences in structure between aged and young samples, suggesting that some ageing mechanisms may act locally within tissues. This study not only reveals possible age-associated differences in ECM protein structures which are tissue-region specific, but also highlights the ability of PLF as a proteomic tool to aid in biomarker discovery

The concept of remembrance in Walter Benjamin

This thesis argues that the role played by the concept of remembrance (Eingedenken) in Walter Benjamin's 'theory of the knowledge of history' and in his engagement with Enlightenment universal history, is a crucial one. The implications of Benjamin's contention that history's 'original vocation' is 'remembrance' have hitherto gone largely unnoticed. The following thesis explores the meaning of the concept of remembrance and assesses the significance of this proposed link between history and memory, looking at both the mnemonic aspect of history and the historical facets of memory. It argues that by mobilising the simultaneously destructive and constructive capacities of remembrance, Benjamin sought to develop a critical historiography which would enable a radical encounter with a previously suppressed past. In so doing he takes up a stance (explicit and implicit) towards existing philosophical conceptions of history, in particular the idea of universal history found in German Idealism. Benjamin reveals an intention to retain the epistemological aspirations of universal history whilst ridding that approach of its apologetic moment. He criticises existing conceptions of history on the basis that each assumes homogeneous time to be the framework in which historical events occur. Insight into the distinctive temporality of remembrance proves to be the touchstone for this critique, and provides a paradigm for a very different conception of time. The thesis goes on to determine what is valid and what is problematic both in this concept of remembrance and in the theory of historical knowledge which it informs, by subjecting both to the most cogent criticisms which can be levelled at them. What emerges is not only the importance of this concept for an understanding of Benjamin's philosophy but the pertinence of this concept for any philosophical account of memory

A carbohydrate-binding protein, B-GRANULE CONTENT 1, influences starch granule size distribution in a dose-dependent manner in polyploid wheat

In Triticeae endosperm (e.g. wheat and barley), starch granules have a bimodal size distribution (with A- and B-type granules) whereas in other grasses the endosperm contains starch granules with a unimodal size distribution. Here, we identify the gene, BGC1 (B-GRANULE CONTENT 1), responsible for B-type starch granule content in Aegilops and wheat. Orthologues of this gene are known to influence starch synthesis in diploids such as rice, Arabidopsis, and barley. However, using polyploid Triticeae species, we uncovered a more complex biological role for BGC1 in starch granule initiation: BGC1 represses the initiation of A-granules in early grain development but promotes the initiation of B-granules in mid grain development. We provide evidence that the influence of BGC1 on starch synthesis is dose dependent and show that three very different starch phenotypes are conditioned by the gene dose of BGC1 in polyploid wheat: normal bimodal starch granule morphology; A-granules with few or no B-granules; or polymorphous starch with few normal A- or B-granules. We conclude from this work that BGC1 participates in controlling B-type starch granule initiation in Triticeae endosperm and that its precise effect on granule size and number varies with gene dose and stage of development