Seasonal Composition of Benthic Diatom Associations in the Cedar River Basin (Iowa)

This is the first detailed report on the taxonomy and ecology of diatoms in the portion of the upper reaches of the Cedar River basin in Iowa. This paper describes the diatom taxa from shallow benthic substrata collected quarterly between 11 October 1975 and 19 February 1977 at 14 sampling stations. Just over 500 frustules were counted from each of the 216 samples obtained. Analysis of water samples collected at the same time as the diatoms indicates these screams have alkaline hard waters rich in nutrients with extreme turbidity level fluctuation at irregular intervals. The 281 diatom taxa identified represented 34 genera, the most diverse being Navicula, Nitzschia, Gomphonema, and Fragilaria (including Synedra). Over 10% of all diatoms counted were Cyclotella meneghiniana. Other diatoms most often reported as plankton but found in this study at greater than 4% total abundance in the haptobenthos included Stephanodiscus parvus, S. hantzschii var. tenuis, Nitzschia acicularis, and Cyclotella atomus. Diatoma vulgare was the only nonmotile pennate so abundant. Thirty-four taxa not previously reported from Iowa were found. The Cedar River and its tributaries have regular seasonal changes in water conditions plus irregular fluctuations reflecting flood effects from storm events or from spring melting. The benthic diatoms respond to these changes in ways similar to diatoms in streams with more predictable disturbance regimes. However regular patterns in distribution and abundance of attached and motile diatoms are unlikely. The data presented strongly suggests that irregular erosion of diatom films and subsequent deposition of upstream benthic and planktonic diatoms along with silt determines the composition of the diatom portion of benthic communities as much as does seasonal succession or substrate affinity

Bose-Einstein condensates with attractive 1/r interaction: The case of self-trapping

Amplifying on a proposal by O'Dell et al. for the realization of Bose-Einstein condensates of neutral atoms with attractive $1/r$ interaction, we point out that the instance of self-trapping of the condensate, without external trap potential, is physically best understood by introducing appropriate "atomic" units. This reveals a remarkable scaling property: the physics of the condensate depends only on the two parameters $N^2 a/a_u$ and $\gamma/N^2$, where $N$ is the particle number, $a$ the scattering length, $a_u$ the "Bohr" radius and $\gamma$ the trap frequency in atomic units. We calculate accurate numerical results for self-trapping wave functions and potentials, for energies, sizes and peak densities, and compare with previous variational results. As a novel feature we point out the existence of a second solution of the extended Gross-Pitaevskii equation for negative scattering lengths, with and without trapping potential, which is born together with the ground state in a tangent bifurcation. This indicates the existence of an unstable collectively excited state of the condensate for negative scattering lengths.Comment: 7 pages, 7 figures, to appear in Phys. Rev.

Decimation and Harmonic Inversion of Periodic Orbit Signals

We present and compare three generically applicable signal processing methods for periodic orbit quantization via harmonic inversion of semiclassical recurrence functions. In a first step of each method, a band-limited decimated periodic orbit signal is obtained by analytical frequency windowing of the periodic orbit sum. In a second step, the frequencies and amplitudes of the decimated signal are determined by either Decimated Linear Predictor, Decimated Pade Approximant, or Decimated Signal Diagonalization. These techniques, which would have been numerically unstable without the windowing, provide numerically more accurate semiclassical spectra than does the filter-diagonalization method.Comment: 22 pages, 3 figures, submitted to J. Phys.

The Role of Osteocyte Estrogen Receptor Beta (ERβ) in Regulating the Skeletal Response to Mechanical Loading

Estrogen’s biological functions are mediated by estrogen binding to estrogen receptors (ER). Understanding what role both ERα and ERβ have in bone maintenance and formation can contribute to possible treatment of osteoporosis. This study examined osteocyte specific deletion of ERβ in mice. The cross of ERβ-floxed mice with DMP1-8kb-Cre mice provided both experimental knockout mice as well as littermate control mice. At 24 weeks of age the left tibiae of all mice were mechanically loaded five days per week for two weeks to induce bone formation. Analysis of cortical bone was conducted using microcomputed tomography (microCT) to measure load-induced changes in bone density and architecture of both loaded and non-loaded limbs. We found a significant effect of load on cortical bone geometry in both male and female knockout and control mice at 37% and 50% bone length. Based on our findings, osteocyte ERβ appears to play a minor role in determining cortical bone geometry in 24 week old mice. We are still investigating the effect of load and genotype on cancellous bone

Reduced healthcare utilisation following successful HCV treatment in HIV co-infected patients with mild liver disease

New direct-acting antivirals (DAA) for hepatitis C virus (HCV) infection have achieved high cure rates in many patient groups previously considered difficult-to-treat, including those HIV/HCV co-infected. The high price of these medications is likely to limit access to treatment, at least in the short term. Early treatment priority is likely to be given to those with advanced disease, but a more detailed understanding of the potential benefits in treating those with mild disease is needed. We hypothesized that successful HCV treatment within a co-infected population with mild liver disease would lead to a reduction in the use and costs of healthcare services in the 5 years following treatment completion. We performed a retrospective cohort study of HIV/HCV-co-infected patients without evidence of fibrosis/cirrhosis who received a course of HCV therapy between 2004 and 2013. Detailed analysis of healthcare utilization up to 5 years following treatment for each patient using clinical and electronic records was used to estimate healthcare costs. Sixty-three patients were investigated, of whom 48 of 63 (76.2%) achieved sustained virological response 12 weeks following completion of therapy (SVR12). Individuals achieving SVR12 incurred lower health utilization costs (£5000 per-patient) compared to (£10 775 per-patient) non-SVR patients in the 5 years after treatment. Healthcare utilization rates and costs in the immediate 5 years following treatment were significantly higher in co-infected patients with mild disease that failed to achieve SVR12. These data suggest additional value to achieving cure beyond the prevention of complications of disease

Synthesis and alkyne-coupling chemistry of cyclomanganated 1- and 3-acetylindoles, 3-formylindole and analogues

The syntheses are reported of new cyclomanganated indole derivatives (1-acetyl-κO-indolyl-κC2)dicarbonylbis(trimethylphosphite)manganese (2), (1-methyl-3-acetyl-κO-indolyl-κC2)tetracarbonylmanganese (4), (3-formyl-κO-indolyl-κC2)tetracarbonylmanganese (5a) and (1-methyl-3-formyl-κO-indolyl-κC2)tetracarbonylmanganese (5b). The unusually complicated crystal structure of 5b has been determined, the first for a cyclomanganated aryl aldehyde. The preparations of a mitomycin-related pyrrolo-indole and related products by thermally promoted and oxidatively (Me3NO) initiated alkyne-coupling reactions of the previously known complex (1-acetyl-κO-indolyl-κC2)tetracarbonylmanganese (1) are reported for different alkynes and solvents. X-ray crystal structures are reported for the dimethyl acetylenedicarboxylate coupling product of 1 (dimethyl 1-methyl-l-hydroxypyrrolo[1,2a]-indole-2,3-dicarboxylate; 6a), and an unusually-cyclised triple insertion product 8 from the coupling of acetylene with 4, in which a cyclopentadiene moiety is η3-allyl-coordinated to Mn through only one double bond and an exocyclic carbon, but which rearranges on heating to an η5-cyclopentadienyl complex

Factors affecting maritime pilots\u27 health and well-being : a systematic review

Background: Maritime pilotage is a demanding occupation where pilots are required to perform complex procedures in sometimes unfamiliar working environments. These psychological stressors, in addition tothe physical demands associated with the role (e.g., reduced sleep, boarding, and departing vessels), may over time have a damaging effect on pilots’ physical and mental health. Therefore the aim of this paper was to systematically review the existing literature on maritime pilots’ health and well-being.Materials and methods: The databases academic search complete, MEDLINE and MEDLINE complete, PsycINFO, PsycARTICLES, PubMed, and ScienceDirect were searched from the earliest available record until 1 May 2015. From an initial pool of 167 manuscripts retrieved, only 18 were peer-reviewed original research and discussed topics associated with maritime pilots’ health and well-being.Results: In total, 29 factors associated with maritime pilot health and well-being were identified. These were loosely categorised into physical (n = 14), psychosocial (n = 8), and workplace issues (n = 7). The most commonly investigated factors were blood pressure or heart rate, sleep or fatigue, smoking and alcohol consumption, perceived stress, and shift duration or cycle. Conclusions: Findings from the review suggest that the prevention of cardiovascular diseases and associated cardio-metabolic risk factors seems to be of paramount importance, with ample evidence indicating that modern-day pilots present as being overweight or obese. What remains unknown is whether these physical factors are associated with variations in psychosocial functioning. Therefore, it is recommended that future pilotage investigations adopt a multidisciplinary approach to better quantify the impact of maritimepilotage on long-term health and well-being