Prospectus, November 9, 1994

https://spark.parkland.edu/prospectus_1994/1020/thumbnail.jp

Effects of zinc supplementation on cognitive function in healthy middle-aged and older adults: the ZENITH study

A randomised double-blind placebo-controlled design was employed to investigate the effects of Zn supplementation on cognitive function in 387 healthy adults aged 55–87 years. Several measures of visual memory, working memory, attention and reaction time were obtained using the Cambridge Automated Neuropsychological Test Battery at baseline and then after 3 and 6 months of 0 (placebo), 15 or 30 mg Zn/d. Younger adults (70 years), and performance improved with practice on some measures. For two out of eight dependent variables, there were significant interactions indicating a beneficial effect (at 3 months only) of both 15 and 30 mg/d on one measure of spatial working memory and a detrimental effect of 15 mg/d on one measure of attention. Further work is required to establish whether these findings generalise to older adults in poorer mental and physical health and with less adequate Zn intake and status than the present sample

Evaluating the approximation of the affinity laws and improving the efficiency estimate for variable speed pumps

Affinity laws relate to the characteristics of pumps operating at different speeds, and in a water distribution context, are usually used to predict the pump curve of variable speed pumps (VSPs). VSPs can adjust the pump curve to meet the network requirements more efficiently with resultant savings of energy. The estimation of the effectiveness of a VSP is based on hydraulic simulations, in which the behavior of VSPs is described using the affinity laws. The affinity laws, however, contain approximations because they do not take into account factors that do not scale with velocity. In particular, the approximation inherent in the affinity law that computes power and efficiency can produce a misleading result, especially for small-size pumps. The research reported in this paper estimates the error in efficiency for a wide range of pump sizes and tests the use of a previously proposed formula as an alternative to the affinity law. Results show that a better estimation can be achieved for the efficiency of small- and medium-size pumps. Moreover the formula can be easily implemented in hydraulic solvers. © 2013 American Society of Civil Engineers.Angus R. Simpson and Angela March

Hubble Space Telescope NICMOS Polarization Observations of Three Edge-on Massive YSOs

Massive young stellar objects (YSOs), like low-mass YSOs, appear to be surrounded by optically thick envelopes and/or disks and have regions, often bipolar, that are seen in polarized scattered light at near-infrared wavelengths. We are using the 0.2'' spatial resolution of NICMOS on Hubble Space Telescope to examine the structure of the disks and outflow regions of massive YSOs in star-forming regions within a few kpc of the Sun. Here we report on 2 micron polarimetry of NGC 6334 V and S255 IRS1. NGC 6334 V consists of a double-lobed bright reflection nebula seen against a dark region, probably an optically thick molecular cloud. Our polarization measurements show that the illuminating star lies ~ 2'' south of the line connecting the two lobes; we do not detect this star at 2 micron, but there are a small radio source and a mid-infrared source at this location. S255 IRS1 consists of two YSOs (NIRS1 and NIRS3) with overlapping scattered light lobes and luminosities corresponding to early B stars. Included in IRS1 is a cluster of stars from whose polarization we determine the local magnetic field direction. Neither YSO has its scattered light lobes aligned with this magnetic field. The line connecting the scattered light lobes of NIRS1 is twisted symmetrically around the star; the best explanation is that the star is part of a close binary and the outflow axis of NIRS1 is precessing as a result of non-coplanar disk and orbit. The star NIRS3 is also offset from the line connecting its two scattered light lobes. We suggest that all three YSOs show evidence of episodic ejection of material as they accrete from dense, optically thick envelopes.Comment: 39 pages, 7 figures, 4 tables To be published in The Astrophysical Journa

A model for malaria treatment evaluation in the presence of multiple species

Plasmodium (P.) falciparum and P. vivax are the two most common causes of malaria. While the majority of deaths and severe morbidity are due to P. falciparum, P. vivax poses a greater challenge to eliminating malaria outside of Africa due to its ability to form latent liver stage parasites (hypnozoites), which can cause relapsing episodes within an individual patient. In areas where P. falciparum and P. vivax are co-endemic, individuals can carry parasites of both species simultaneously. These mixed infections complicate dynamics in several ways; treatment of mixed infections will simultaneously affect both species, P. falciparum can mask the detection of P. vivax, and it has been hypothesised that clearing P. falciparum may trigger a relapse of dormant P. vivax. When mixed infections are treated for only blood-stage parasites, patients are at risk of relapse infections due to P. vivax hypnozoites. We present a stochastic mathematical model that captures interactions between P. falciparum and P. vivax, and incorporates both standard schizontocidal treatment (which targets blood-stage parasites) and radical treatment (which additionally targets liver-stage parasites). We apply this model to assess the implications of different treatment coverage of radical cure for mixed and P. vivax infections and a so-called "unified radical cure" treatment strategy for P. falciparum, P. vivax and mixed infections. We find that a unified radical cure strategy, with G6PD screening, leads to a substantially lower incidence of malaria cases and deaths overall. We perform a one-way sensitivity analysis to highlight important model parameters

Spitzer IRS Observations of the Galactic Center: Shocked Gas in the Radio Arc Bubble

We present Spitzer IRS spectra (R ~600, 10 - 38 micron) of 38 positions in the Galactic Center (GC), all at the same Galactic longitude and spanning plus/minus 0.3 degrees in latitude. Our positions include the Arches Cluster, the Arched Filaments, regions near the Quintuplet Cluster, the ``Bubble'' lying along the same line-of-sight as the molecular cloud G0.11-0.11, and the diffuse interstellar gas along the line-of-sight at higher Galactic latitudes. From measurements of the [O IV], [Ne II], [Ne III], [Si II], [S III], [S IV], [Fe II], [Fe III], and H_2 S(0), S(1), and S(2) lines we determine the gas excitation and ionic abundance ratios. The Ne/H and S/H abundance ratios are ~ 1.6 times that of the Orion Nebula. The main source of excitation is photoionization, with the Arches Cluster ionizing the Arched Filaments and the Quintuplet Cluster ionizing the gas nearby and at lower Galactic latitudes including the far side of the Bubble. In addition, strong shocks ionize gas to O^{+3} and destroy dust grains, releasing iron into the gas phase (Fe/H ~ 1.3 times 10^{-6} in the Arched Filaments and Fe/H ~ 8.8 times 10^{-6} in the Bubble). The shock effects are particularly noticeable in the center of the Bubble, but O$^{+3}$ is present in all positions. We suggest that the shocks are due to the winds from the Quintuplet Cluster Wolf-Rayet stars. On the other hand, the H_2 line ratios can be explained with multi-component models of warm molecular gas in photodissociation regions without the need for H_2 production in shocks.Comment: 51 pages, 17 figures To be published in the Astrophysical Journa

Dietary macronutrient composition impacts gene regulation in adipose tissue

Diet is a key lifestyle component that influences metabolic health through several factors, including total energy intake and macronutrient composition. While the impact of caloric intake on gene expression and physiological phenomena in various tissues is well described, the influence of dietary macronutrient composition on these parameters is less well studied. Here, we use the Nutritional Geometry framework to investigate the role of macronutrient composition on metabolic function and gene regulation in adipose tissue. Using ten isocaloric diets that vary systematically in their proportion of energy from fat, protein, and carbohydrates, we find that gene expression and splicing are highly responsive to macronutrient composition, with distinct sets of genes regulated by different macronutrient interactions. Specifically, the expression of many genes associated with Bardet-Biedl syndrome is responsive to dietary fat content. Splicing and expression changes occur in largely separate gene sets, highlighting distinct mechanisms by which dietary composition influences the transcriptome and emphasizing the importance of considering splicing changes to more fully capture the gene regulation response to environmental changes such as diet. Our study provides insight into the gene regulation plasticity of adipose tissue in response to macronutrient composition, beyond the already well-characterized response to caloric intake