Effects of Retreating Glaciers on Seasonal Water Availability

Glacial recession caused by slowly warming temperatures will have a substantial impact on the availability of freshwater for hundreds of thousands to millions of people in the coming decades. The meltwater provided by glaciers in the summer months is a vital resource to several regions of the world; some much more reliant than others. This presentation will highlight the role that glaciers play in the hydrology of glacially fed river systems, and attempt to understand the severity of changes to future water availability as a result of retreating glaciers. Freshwater shortage could have devastating effects on agricultural yield, drinking water availability, hydroelectric power generation, sanitation, industrial processing and dozens of other uses especially in the late summer of already water strained areas. Despite the amount of research being done on this subject, there is still significant evidence missing for drawing conclusions on the state of future freshwater output of glaciers. Further knowledge and understanding of the topic may prove critical in adapting to water scarcity for certain areas

Defining the Clinical Spectrum of Sickle Cell Disease in Tanzania: A Clinico-Epidemiological Study

Introduction: The burden of Sickle Cell Disease (SCD) in Africa is high; having over 75% of annual global births and mortality reaching 95% in childhood. Introduction of interventions, which could prevent 70% of deaths, have been limited because of lack of local evidence. This study described the clinical spectrum of SCD in Tanzania as the first step in providing evidence to guide targeted interventions. Methods: SCD patients attending Muhimbili Hospital in Dar-es-Salaam, Tanzania were recruited between 2004 and 2009. Prospective surveillance of clinical and laboratory information was done at outpatient clinic and during hospitalisation. Specific investigations included blood cultures on all hospitalised SCD patients, Transcranial Doppler (TCD) ultrasonography to measure cerebral blood flow velocity (CBFv) and HPLC to measure levels of foetal haemoglobin (HbF). The outcomes of interest were death, hospitalisation, malaria, bacteraemia and stroke. Results: 1,725 SCD patients [mean age 9.7 (SD 7.9) years; 10% below 2 years] were enrolled with information recorded from 14,000 visits during the study period. 12% of enrolled SCD patients were lost to follow up and 23% of 86 deaths occurred at the hospital. The mortality was 2 deaths/100 person years of observation (PYO); highest under 5 years and independently associated with low haemoglobin (Hazard ratio 0.7 95%CI 0.6-0.8; p0.01). 504 (29%) of the SCD cohort were hospitalised with pain, fever and anaemia as the commonest cause of hospitalisation. SCD patients had less malaria than non-SCD patients at clinic (OR, 0.46; 95% CI, 0.25-0.94; P = .01) and during hospitalisation (OR, 0.53; 95% CI, 0.32-0.86; P = .008). In SCD patients, prevalence of malaria was higher during hospitalisation and associated with severe anaemia and death. 43 out of 890 hospitalisations had bacteraemia (4.8%) with Staphylococcus aureus (28%), non-typhii Salmonella (21%) and Streptococcus pneumoniae (7%) as the most common organisms. The mean CBFv in 372 patients (2 - 16 years) was 132 cm/sec with CBFv > 200cm/sec occurring in 40 (10%) patients. The incidence of stroke was 0.3 per 100PYO; associated with sickle haemoglobin and reticulocyte count but not with CBFv. The mean HbF level in 1,669 SCD patients was 6.3 (SD 4.7) % with no association with mortality and hospitalisation. Conclusion: This study has highlighted the burden of disease to individuals and health system. The findings have important implications for policies to improve healthcare as well as identifying areas for further research

Urbanization and freshwater salinity: Impacts on water quality, sediment, and microbial communities in semi-arid streams

Stream ecosystems can be sensitive to watershed urbanization, but less is known about how streams respond to urbanization in semi-arid cities. To characterize how urbanization and altered salinity regimes affect stream chemistry and microbial activity, I conducted (1) a mesocosm experiment to investigate how press versus pulse salinity regimes altered biogeochemical cycles in stream sediments and (2) a field survey of streams in Reno, Nevada. The mesocosm experiment results revealed that the press salinity regime caused the greatest fluxes in ammonium and potassium from exposed stream sediments, while microbial activity rates were not affected. Results from the field survey demonstrated that the heterogenous underlying lithology of Reno imparted a stronger signal on stream chemistry than watershed urbanization in paired sites. The results of this work characterize the wide temporal and spatial variability in how stream chemistry and microbial activity respond to urbanization and altered salinity regimes in a semi-arid city

Strategies Small Restaurant Owners Use to Reduce Food Waste and Increase Profits

There were 133 billion pounds of food that went to waste in the United States in 2014, leading to $161.6 billion in economic loss. Of this waste, 89 billion pounds occurred in restaurants and other food service facilities. A case study was used to explore the strategies small, independent, family-owned restaurants owners used to reduce food waste. Four small independent, family-owned restaurants owners located in the Washington, DC, metro area participated in the study. These owners were selected based on their revenue and years of survival. Stakeholders theory was the conceptual framework in which the study was grounded. Face-to-face interviews with participants and company financial documents comprised the data. Interview transcripts, member checking results, and financial documents were analyzed for emergent themes. The 3 themes that emerged from this study are employee training, communication among stakeholders, and customer loyalty. The implications for social change include the potential to provide new strategies that can help small, independent, family-owned restaurants reduce food waste, increase profits, and improve the economic conditions of communities in the Washington, DC metro area

Advances in Raman hyperspectral compressive detection instrumentation for fast label free classification, quantitation and imaging

Multiple prototypes of hyperspectral compressive detection (CD) Raman spectrometers have previously been constructed in the Ben-Amotz lab and have proven to be useful for fast, label-free chemical identification, quantitation and imaging. The CD spectrometer consists of a volume holographic grating (VHG) that linearly disperses the Raman photons into its component wavelengths and all wavelengths are focused onto a digital micromirror devise (DMD). The DMD is an optical modulator that consists of an array of programmable 10μm mirrors that can reflect photons in either +12° or -12° to the incoming light. The DMD is tilted such that the +12° photons go back through the focusing lens and the VHG and is focused onto a single 150μm photon counting avalanche photodiode detector(APD). In chapter 1 of the thesis I describe the construction of a new CD Raman spectrometer capable of fast hyperspectral imaging that has better photon collection efficiency and fewer photon losses compared to its predecessors. The new spectrometer consists of a VHG and a DMD, however, the DMD is not tilted but is perpendicular to the incoming Raman photons. All the Raman photons modulated by the DMD are symmetrically detected in the +12° and -12° by two photon counting photomultiplier tube(PMT) detector modules. The new spectrometer avoids a double pass through the optics and hence has fewer losses associated due to reflection transmission of the optics. Full spectral measurements are made by consecutively scanning through columns of the DMD mirrors and measuring the intensity of photons associated with each wavelength. CD measurements are made by multiplexing wavelengths channels onto the detectors and can be done by applying optimal binary(OB) or Hadamard filters. The new optical design has a spectral window from 150cm-1 to 4000 cm-1 and the improvement in the photon collection efficiency allows classification and imaging speeds of 10μs per point with 13mW of laser power on the sample, and is significantly faster than measurements made with the previous prototype. In chapter 2 of the thesis I describe the construction of a new instrument which is equipped with both a hyperspectral CD spectrometer as well as a traditional Czerny Turner spectrometer. A flip mirror after the Raman microscope directs the Raman scattered beam either towards the CD spectrometer (with the mirror down) or towards the Czerny Turner spectrometer. This instrument allows us to perform head to head comparisons of the two spectrometers using the same Raman scattered photons emitted by the sample. The CD spectrometer uses hardware optical filters to perform compressed chemometric measurements to classify chemicals. The traditional spectrometer uses the CCD to measure full spectral data and chemometric analysis is performed to extract lower dimensional chemical information post measurement. Chemical classification results obtained using two sets of chemicals with differing degrees of spectral overlap show that CD classification is comparable to full spectral classification in the high signal regime. However, for signals consisting of less than 1000 total photon counts, CD classification outperforms full spectral classification. In chapter 3 of the thesis, Raman spectroscopy is used to probe changes in vibrational spectra of nucleotide solutions and hanging droplets containing RNA crystals at different pH. Self-modeling curve resolution (SMCR) applied to full Raman is used to extract solute correlated (SC) Raman spectral components that contain solute spectra with minimal interference from the surrounding solvent. The goal of these studies is to show that Raman spectroscopy can be used to study biological molecules in aqueous environments, with minimal sample preparation and without the need of labels

Communication interventriculaire post infarctus du myocarde: réparation chirurgicale

La communication interventriculaire (CIV) post infarctus du myocarde est une complication aiguë. l’incidence de cette complication est évaluée entre 1% et 2%, mais elle est responsable de 5% des décès en phase aiguë de l’infarctus. Sa prise en charge est chirurgicale, avec la difficulté de réparation à partir des tissus infarcis fragiles. Le septum interventriculaire a une double vascularisation, ce qui explique les deux types de localisation de CIV: CIV antérieure par occlusion de l’artère interventriculaire antérieure (IVA), qui est la plus fréquente, et la CIV postérieure par occlusion d’une coronaire droite dominante ou plus rarement d’une circonflexe dominante. Nous rapportons le cas d’une réparation chirurgicale, faite avec succès, d’une CIV antérieure de 15mm, chez un patient de 75 ans, qui avait une occlusion de l’IVA. La réparation a été faite sous circulation éxtracorporelle, avec résection des tissus infarcis et mise en place d’un patch adapté au défect. Le patch a été positionné du coté ventriculaire gauche. Des points en U sur feutre de Teflon ont fixé le patch. Les suites opératoires ont été favorables et le patient est sorti du bloc opératoire avec de faible dose de DOBUTAMINE

Human-animal relationships and ecocriticism: a study of the representation of animals in poetry from Malawi, Zimbabwe, and South Africa

Ph.D. Faculty of Humanities, University of the Witwatersrand, 2011This study analyses the manner in which animals are represented in selected poetry from Malawi, Zimbabwe and South Africa. It discusses the various modes of animal representation the poets draw on, and the ideological influences on their manner of animal representation. It explores the kinds of poetic forms the poets employ in their representation of animals and examines the manner in which ecological or environmental issues are reflected in the poetry. Further, the study determines the extent to which the values expressed in the poems are consistent with, or different from, current ecological orthodoxies and the ways in which the metaphors generated in relation to animals influence the way we treat them. The study shows that in the selected poetry animals occupy a significant position in the poets’ exploration of social, psychological, political, and cultural issues. As symbols in, and subjects of, the poetry animals, in particular, and nature in general, function as tools for the poets’ conceptualisation and construction of a wide range of cultural, political, and philosophical ideas, including among others, issues of justice, identity, compassion, relational selfhood, heritage, and belonging to the cosmos. Hence, the animal figure in the poetry acts as a site for the convergence of a variety of concepts the poets mobilise to grapple with and understand relevant political, social, psychological and ecological ideas. The study advances the argument that studying animal representation in the selected poetry reveals a range of ecological sensibilities, as well as the limits of these, and opens a window through which to view and appreciate the poets’ conception, construction and handling of a variety of significant ideas about human to human relationships and human-animal/nature relationships. Further, the study argues that the poets’ social vision influences their animal representation and that their failures at times to fully see or address the connection between forms of abuse (nature and human) undercuts their liberationist quests in the poetry

Flow Structure and Transport Characteristics of Feeding and Exchange Currents Generated by Upside-Down Cassiopea Jellyfish

Quantifying the flows generated by the pulsations of jellyfish bells is crucial for understanding the mechanics and efficiency of their swimming and feeding. Recent experimental and theoretical work has focused on the dynamics of vortices in the wakes of swimming jellyfish with relatively simple oral arms and tentacles. The significance of bell pulsations for generating feeding currents through elaborate oral arms and the consequences for particle capture are not as well understood. To isolate the generation of feeding currents from swimming, the pulsing kinematics and fluid flow around the benthic jellyfish Cassiopea spp. were investigated using a combination of videography, digital particle image velocimetry and direct numerical simulation. During the rapid contraction phase of the bell, fluid is pulled into a starting vortex ring that translates through the oral arms with peak velocities that can be of the order of 10 cm s–1. Strong shear flows are also generated across the top of the oral arms throughout the entire pulse cycle. A coherent train of vortex rings is not observed, unlike in the case of swimming oblate medusae such as Aurelia aurita. The phase-averaged flow generated by bell pulsations is similar to a vertical jet, with induced flow velocities averaged over the cycle of the order of 1–10 mm s–1. This introduces a strong near-horizontal entrainment of the fluid along the substrate and towards the oral arms. Continual flow along the substrate towards the jellyfish is reproduced by numerical simulations that model the oral arms as a porous Brinkman layer of finite thickness. This two-dimensional numerical model does not, however, capture the far-field flow above the medusa, suggesting that either the three-dimensionality or the complex structure of the oral arms helps to direct flow towards the central axis and up and away from the animal

Relationships between mineralogical and physico-mechanical properties of granitic aggregates

Several parameters are involved in the choice of the aggregates for concrete with good features: size, texture, quality, mineralogy, shape ... This work presents a study to characterize these materials through their geometrical properties (size, shape and size distribution), mechanical (uniaxial compressive strength and modulus of elasticity), physical (porosity, water absorption) and finally chemical and mineralogical properties. The relationships between mineralogical and physico-mechanical properties of granitic rocks from the Haute Garonne, France, were investigated. The relationships between these properties are described by simple regression analyzes. The results indicate that feldspar, chlorite and quartz contents of the studied rock-types significantly influence their physico-mechanical properties. Additionally, we find that the mechanical properties in compression are much higher when the mass percentage of quartz is important