Studies on the Life Cycle and Transmission of \u3ci\u3eCougourdella\u3c/i\u3e Sp., A Microsporidian Parasite of \u3ci\u3eGlossosoma Nigrior\u3c/i\u3e (Trichoptera: Glossosomatidae)

The trichopteran Glossosoma nigrior, the dominant benthic invertebrate grazer in Michigan trout streams, hosts a microsporidian (Protozoa) pathogen, Cougourdella sp., which strongly regulates the population density of larvae in the stream. In order to better understand the interactions between these two species, two possible modes of pathogen transmission, oral and transovum, were investigated. While both sexes of adult G. nigrior were found to be infected with mature environmental spores, spores were not found associated with reproductive tissue. This suggests that transovum transmission does not occur in this system. Glossosoma nigrior, when ex- posed to viable spores taken from infected larvae, did not produce Cougourdella sp. infections, which suggests that oral transmission also does not occur. It is possible that an intermediate host is required

The reproductive biology of the porbeage shark (Lamna nasus) in the western North Atlantic Ocean

Reproductive organs from 393 male and 382 female porbeagles (Lamna nasus), caught in the western North Atlantic Ocean, were examined to determine size at maturity and reproductive cycle. Males ranged in size from 86 to 246 cm fork length (FL) and females ranged from 94 to 288 cm FL. Maturity in males was best described by an inflection in the relationship of clasper length to fork length when combined with clasper calcification. Males matured between 162 and 185 cm FL and 50% were mature at 174 cm FL. In females, all reproductive organ measurements related to body length showed a strong inflection around the size of maturity. Females matured between 210 and 230 cm FL and 50% were mature at 218 cm FL. After a protracted fall mating period (September–November), females give birth to an average of 4.0 young in spring (April−June). As in other lamnids, young are nourished through oophagy. Evidence from this study indicated a one-year reproductive cycle and gestation period lasting 8–9 months

A yield model for walking catfish production in aquaculture systems

A yield model for Clarias culture was produced using a combination of laboratory data for Clarias lazera and field data on Clarias batrachus culture in Thailand. The model was used for simulations to fulfil three distinct objectives: (1) to consolidate knowledge of fish physiology and aquaculture practices for Clarias into a model which can be validated; (2) to determine sensitivity of predictions to variation in model parameters; and (3) to predict yield of Clarias ponds under different stocking density, size at stocking, and type of containment. The accuracy of this model was tested with an independent data set of 32 grow-out periods. The model was relatively poor at predicting yield when the measured feeding rate was input (r2=0.022), but reasonably good at predicting yield if maximum feeding rate was input (r2=0.52). This may reflect poor data collection of feeding rate in the ponds. Sensitivity analyses indicated that changes in parameters related to maximum consumption showed high importance in predicting yield, while changes in metabolic parameters had low importance. A doubling of feeding rate increased yield 548% in earthen ponds and 465% in concrete tanks. Density stocked was of secondary importance in increasing simulated yield, while size at stocking was relatively unimportant. The maximum consumption rate of different food types (pellets, trash fish) was also extremely important in determining simulated yield.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27263/1/0000273.pd

Influence of Stream Location in a Drainage Network on the Index of Biotic Integrity

The index of biotic integrity (IBI) has become a widely used tool for assessing the condition of stream fish communities and the overall biological status of streams. Because the location of a stream in a drainage network can influence the species richness offish communities and because species richness is an important component of the IBI, we examined the influence of stream spatial location on the IBI. We found that IBI scores for headwater streams in three Illinois drainage basins were significantly lower than those calculated for tributary streams of similar size connecting directly to larger streams. This difference in IBI was related to the increased species richness and to a greater number of sucker and darter species in tributaries that drain into larger, main‐channel streams. Because of the influence of tributary location on the IBI, expected values for headwater tributary streams should be developed independently from those developed for main‐channel tributary streams. Failure to do so can result in a substantial underestimation of the IBI of headwater tributary streams or an overestimation of main‐channel tributaries.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142315/1/tafs0635.pd

The Metagalactic Ionizing Radiation Field at Low Redshift

We compute the ionizing radiation field at low redshift, arising from Seyferts, QSOs, and starburst galaxies. This calculation combines recent Seyfert luminosity functions, extrapolated ultraviolet fluxes from our IUE-AGN database, and a new intergalactic opacity model based on Hubble Space Telescope and Keck Ly-alpha absorber surveys. At z = 0 for AGN only, our best estimate for the specific intensity at 1 Ryd is I_0 = 1.3 (+0.8/-0.5) x 10^-23 ergs/cm^2/s/Hz/sr, independent of H_0, Omega_0, and Lambda. The one-sided ionizing photon flux is Phi_ion = 3400 (+2100/-1300) photons/cm^2/s, and the H I photoionization rate is Gamma_HI = 3.2 (+2.0/-1.2) x 10^-14 s^-1 for alpha_s = 1.8. We also derive Gamma_ HI for z = 0 - 4. These error ranges reflect uncertainties in the spectral indexes for the ionizing EUV (alpha_s = 1.8 +/- 0.3) and the optical/UV (alpha_UV = 0.86 +/- 0.05), the IGM opacity model, the range of Seyfert luminosities (0.001 - 100 L*) and the completeness of the luminosity functions. Our estimate is a factor of three lower than the most stringent upper limits on the ionizing background (Phi_ion < 10^4 photons/cm^2/s) obtained from H-alpha observations in external clouds, and it lies within the range implied by other indirect measures. Starburst galaxies with a sufficiently large Lyman continuum escape fraction, f_ esc > 0.05, may provide a comparable background to AGN, I_0 (z=0) = 1.1 (+1.5/-0.7) x 10^{-23). An additional component of the ionizing background of this magnitude would violate neither upper limits from H-alpha observations nor the acceptable range from other measurements.Comment: 30 pages, 9 figures, accepted for Astronomical J. (Oct. 1999

Developing core sets for persons following amputation based on the International Classification of Functioning, Disability and Health as a way to specify functioning

Amputation is a common late stage sequel of peripheral vascular disease and diabetes or a sequel of accidental trauma, civil unrest and landmines. The functional impairments affect many facets of life including but not limited to: Mobility; activities of daily living; body image and sexuality. Classification, measurement and comparison of the consequences of amputations has been impeded by the limited availability of internationally, multiculturally standardized instruments in the amputee setting. The introduction of the International Classification of Functioning, Disability and Health (ICF) by the World Health Assembly in May 2001 provides a globally accepted framework and classification system to describe, assess and compare function and disability. In order to facilitate the use of the ICF in everyday clinical practice and research, ICF core sets have been developed that focus on specific aspects of function typically associated with a particular disability. The objective of this paper is to outline the development process for the ICF core sets for persons following amputation. The ICF core sets are designed to translate the benefits of the ICF into clinical routine. The ICF core sets will be defined at a Consensus conference which will integrate evidence from preparatory studies, namely: (a) a systematic literature review regarding the outcome measures of clinical trails and observational studies, (b) semi-structured patient interviews, (c) international experts participating in an internet-based survey, and (d) cross-sectional, multi-center studies for clinical applicability. To validate the ICF core sets field-testing will follow. Invitation for participation: The development of ICF Core Sets is an inclusive and open process. Anyone who wishes to actively participate in this process is invited to do so

Abnormalities in autonomic function in obese boys at-risk for insulin resistance and obstructive sleep apnea.

Study objectivesCurrent evidence in adults suggests that, independent of obesity, obstructive sleep apnea (OSA) can lead to autonomic dysfunction and impaired glucose metabolism, but these relationships are less clear in children. The purpose of this study was to investigate the associations among OSA, glucose metabolism, and daytime autonomic function in obese pediatric subjects.MethodsTwenty-three obese boys participated in: overnight polysomnography; a frequently sampled intravenous glucose tolerance test; and recordings of spontaneous cardiorespiratory data in both the supine (baseline) and standing (sympathetic stimulus) postures.ResultsBaseline systolic blood pressure and reactivity of low-frequency heart rate variability to postural stress correlated with insulin resistance, increased fasting glucose, and reduced beta-cell function, but not OSA severity. Baroreflex sensitivity reactivity was reduced with sleep fragmentation, but only for subjects with low insulin sensitivity and/or low first-phase insulin response to glucose.ConclusionsThese findings suggest that vascular sympathetic activity impairment is more strongly affected by metabolic dysfunction than by OSA severity, while blunted vagal autonomic function associated with sleep fragmentation in OSA is enhanced when metabolic dysfunction is also present

Of gastro and the gold standard: evaluation and policy implications of norovirus test performance for outbreak detection

<p>Abstract</p> <p>Background</p> <p>The norovirus group (NVG) of caliciviruses are the etiological agents of most institutional outbreaks of gastroenteritis in North America and Europe. Identification of NVG is complicated by the non-culturable nature of this virus, and the absence of a diagnostic gold standard makes traditional evaluation of test characteristics problematic.</p> <p>Methods</p> <p>We evaluated 189 specimens derived from 440 acute gastroenteritis outbreaks investigated in Ontario in 2006–07. Parallel testing for NVG was performed with real-time reverse-transcriptase polymerase chain reaction (RT²-PCR), enzyme immunoassay (EIA) and electron microscopy (EM). Test characteristics (sensitivity and specificity) were estimated using latent class models and composite reference standard methods. The practical implications of test characteristics were evaluated using binomial probability models.</p> <p>Results</p> <p>Latent class modelling estimated sensitivities of RT²-PCR, EIA, and EM as 100%, 86%, and 17% respectively; specificities were 84%, 92%, and 100%; estimates obtained using a composite reference standard were similar. If all specimens contained norovirus, RT²-PCR or EIA would be associated with > 99.9% likelihood of at least one test being positive after three specimens tested. Testing of more than 5 true negative specimens with RT²-PCR would be associated with a greater than 50% likelihood of a false positive test.</p> <p>Conclusion</p> <p>Our findings support the characterization of EM as lacking sensitivity for NVG outbreaks. The high sensitivity of RT²-PCR and EIA permit identification of NVG outbreaks with testing of limited numbers of clinical specimens. Given risks of false positive test results, it is reasonable to limit the number of specimens tested when RT²-PCR or EIA are available.</p

A risk score including body mass index, glycated haemoglobin and triglycerides predicts future glycaemic control in people with type 2 diabetes

AimTo identify, predict and validate distinct glycaemic trajectories among patients with newly diagnosed type 2 diabetes treated in primary care, as a first step towards more effective patient-centred care. MethodsWe conducted a retrospective study in two cohorts, using routinely collected individual patient data from primary care practices obtained from two large Dutch diabetes patient registries. Participants included adult patients newly diagnosed with type 2 diabetes between January 2006 and December 2014 (development cohort, n=10528; validation cohort, n=3777). Latent growth mixture modelling identified distinct glycaemic 5-year trajectories. Machine learning models were built to predict the trajectories using easily obtainable patient characteristics in daily clinical practice. ResultsThree different glycaemic trajectories were identified: (1) stable, adequate glycaemic control (76.5% of patients); (2) improved glycaemic control (21.3% of patients); and (3) deteriorated glycaemic control (2.2% of patients). Similar trajectories could be discerned in the validation cohort. Body mass index and glycated haemoglobin and triglyceride levels were the most important predictors of trajectory membership. The predictive model, trained on the development cohort, had a receiver-operating characteristic area under the curve of 0.96 in the validation cohort, indicating excellent accuracy. ConclusionsThe developed model can effectively explain heterogeneity in future glycaemic response of patients with type 2 diabetes. It can therefore be used in clinical practice as a quick and easy tool to provide tailored diabetes care

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes