Ammonium uptake and regeneration rates in a coastal upwelling regime

Ammonium uptake and regeneration rates were measured in time course experiments with 15N as a tracer. Both ammonium uptake and regeneration rates measured over 12 to 18 h remained essentially constant. However, as the length of the incubations increased the amount of usable data decreased dramatically due to substrate depletion and recycling of 15N. Mass balance calculations indicated that 22 to 51% of the ammonium removed from the dissolved pool was not recovered in the particulate fraction. This appeared to be a more serious problem at 0 and 8 m (47%) than at 25 m (22%). As a result, ammonium uptake rates were probably underestimated. At 0, 12, and 20 m uptake rates either balanced or exceeded regeneration rates, while at 8 and 25 m net regeneration occurred. The fastest rates were measured during upwelling-induced phytoplankton blooms, intermediate rates characterized post-bloom conditions and the lowest rates coincided with an active upwelling event. Ammonium uptake rates were highest during the upwelling season (11 to 17 mmol N m-2 d-1) and lowest during the non-upwelling season (3 mmol N m-2 d-1), whereas regeneration rates did not differ significantly between seasons (11 to 20 mmol N m-2 d-1)

Efficacy of hepatic transplantation in patients with primary sclerosing cholangitis

Controlled trials to assess the therapeutic benefit of orthotopic hepatic transplantation (OHTx) for primary sclerosing cholangitis (PSC) cannot be justified in view of improvement of patient survival after this operation since 1981. However, the actual patient survival with OHTx can be compared with the Mayo model estimated survival probabilities without OHTx. This model, which encompasses physical, biochemical and histopathologic parameters of PSC, was constructed from a study of 392 conservatively treated PSC patients at five international centers in England and North America. We compared the actual survival of 216 adult patients with the diagnosis of advanced PSC who underwent hepatic replacement with the expected survival estimated by the Mayo PSC natural history model, 'the simulated control technique.' OHTx was performed at the University of Pittsburgh and Mayo Medical Center between 5 December 1981 and 26 December 1990. The mean (plus or minus standard deviation) post-OHTx follow-up period was 34 ± 25 months (range of zero to 104 months). Before transplantation, biliary or portal hypertensive operation, or both, was performed upon 104 patients. At operation, the mean age of recipients was 42.1 ± 11.3 years and the mean value of total serum bilirubin was 13.3 ± 13.0 milligrams per deciliter. Extensive septal fibrosis and cirrhosis were histologically documented in 97 percent of the patients, with splenomegaly in 63 percent. Immunosuppressive therapy was based primarily on cyclosporin in 184 recipients and FK-506 in 32. Within six months, the Kaplan-Meier survival probability after OHTx (0.89) already was higher than predicted by the Mayo model (0.83). At five years, the Kaplan-Meier actual survival with OHTx was 0.73 compared with 0.28 expected Mayo model survival. The overall increased survival rate with transplantation was statistically significant (chi-square equals 126.6; p<0.001). At all risk stratifications, OHTx significantly improved survival with a p value of 0.031 (low risk), 0.001 (moderate risk) and <0.001 (high risk). Thus, OHTx is effective therapy for PSC. Disease gravity and unsuspected cholangiocarcinoma in the excised native liver adversely influenced short and long term survival rates after transplantation, respectively

What a difference a term makes:the effect of educational attainment on marital outcomes in the UK

Abstract In the past, students in England and Wales born within the first 5 monthsof the academic year could leave school one term earlier than those born later inthe year. Focusing on women, those who were required to stay on an extra termmore frequently hold some academic qualification. Using having been required tostay on as an exogenous factor affecting academic attainment, we find that holding alow-level academic qualification has no effect on the probability of being currentlymarried for women aged 25 or above, but increases the probability of the husbandholding some academic qualification and being economically active.33 Halama

Forest Statistics for Maine, 1971 and 1982

https://digitalmaine.com/usda_feddocs/1001/thumbnail.jp

Institutional strategies for capturing socio-economic impact of academic research

Evaluation of socio-economic impact is an emerging theme for publicly-funded academic research. Within this context the paper suggests that the concept of institutional research capital be expanded to include the capture and evaluation of socio-economic impact. Furthermore, it argues that understanding the typology of impacts and the tracking from research to impact will assist the formulation of institutional strategies for capturing socio-economic impact. A three-stage approach is proposed for capturing and planning activities to enhance the generation of high-quality impact. Stage one outlines the critical role of user engagement that facilitates the tracking of such impact. Stage two employs an analytical framework based on the criteria of ‘depth’ and ‘spread’ to evaluate impacts that have been identified. Stage three utilizes the outcomes of the framework to devise strategies, consisting of either further research (to increase depth) or more engagement (to increase spread) that will improve the generation of higher quality impact

Tools for delivering entomopathogenic fungi to malaria mosquitoes: effects of delivery surfaces on fungal efficacy and persistence.

BACKGROUND\ud \ud Entomopathogenic fungi infection on malaria vectors increases daily mortality rates and thus represents a control measure that could be used in integrated programmes alongside insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS). Before entomopathogenic fungi can be integrated into control programmes, an effective delivery system must be developed.\ud \ud METHODS\ud \ud The efficacy of Metarhizium anisopliae ICIPE-30 and Beauveria bassiana I93-825 (IMI 391510) (2 × 10(10) conidia m(-2)) applied on mud panels (simulating walls of traditional Tanzanian houses), black cotton cloth and polyester netting was evaluated against adult Anopheles gambiae sensu stricto. Mosquitoes were exposed to the treated surfaces 2, 14 and 28 d after conidia were applied. Survival of mosquitoes was monitored daily.\ud \ud RESULTS\ud \ud All fungal treatments caused a significantly increased mortality in the exposed mosquitoes, descending with time since fungal application. Mosquitoes exposed to M. anisopliae conidia on mud panels had a greater daily risk of dying compared to those exposed to conidia on either netting or cotton cloth (p < 0.001). Mosquitoes exposed to B. bassiana conidia on mud panels or cotton cloth had similar daily risk of death (p = 0.14), and a higher risk than those exposed to treated polyester netting (p < 0.001). Residual activity of fungi declined over time; however, conidia remained pathogenic at 28 d post application, and were able to infect and kill 73 - 82% of mosquitoes within 14 d.\ud \ud CONCLUSION\ud \ud Both fungal isolates reduced mosquito survival on immediate exposure and up to 28 d after application. Conidia were more effective when applied on mud panels and cotton cloth compared with polyester netting. Cotton cloth and mud, therefore, represent potential substrates for delivering fungi to mosquitoes in the field

Simultaneous PET-MRI Studies of the Concordance of Atrophy and Hypometabolism in Syndromic Variants of Alzheimer's Disease and Frontotemporal Dementia: An Extended Case Series

Background: Simultaneous PET-MRI is used to compare patterns of cerebral hypometabolism and atrophy in six different dementia syndromes. Objectives: The primary objective was to conduct an initial exploratory study regarding the concordance of atrophy and hypometabolism in syndromic variants of Alzheimer’s disease (AD) and frontotemporal dementia (FTD). The secondary objective was to determine the effect of image analysis methods on determination of atrophy and hypometabolism. Method: PET and MRI data were acquired simultaneously on 24 subjects with six variants of AD and FTD (n = 4 per group). Atrophy was rated visually and also quantified with measures of cortical thickness. Hypometabolism was rated visually and also quantified using atlas- and SPM-based approaches. Concordance was measured using weighted Cohen’s kappa. Results: Atrophy-hypometabolism concordance differed markedly between patient groups; kappa scores ranged from 0.13 (nonfluent/agrammatic variant of primary progressive aphasia, nfvPPA) to 0.49 (posterior cortical variant of AD, PCA). Heterogeneity was also observed within groups; the confidence intervals of kappa scores ranging from 0–0.25 for PCA to 0.29–0.61 for nfvPPA. More widespread MRI and PET changes were identified using quantitative methods than on visual rating. Conclusion: The marked differences in concordance identified in this initial study may reflect differences in the molecular pathologies underlying AD and FTD syndromic variants but also operational differences in the methods used to diagnose these syndromes. The superior ability of quantitative methodologies to detect changes on PET and MRI, if confirmed on larger cohorts, may favor their usage over qualitative visual inspection in future clinical diagnostic practic

Access to housing subsidies, housing status, drug use and HIV risk among low-income U.S. urban residents

<p>Abstract</p> <p>Background</p> <p>Much research has shown an association between homelessness and unstable housing and HIV risk but most has relied on relatively narrow definitions of housing status that preclude a deeper understanding of this relationship. Fewer studies have examined access to housing subsidies and supportive housing programs among low-income populations with different personal characteristics. This paper explores personal characteristics associated with access to housing subsidies and supportive housing, the relationship between personal characteristics and housing status, and the relationship between housing status and sexual risk behaviors among low-income urban residents.</p> <p>Methods</p> <p>Surveys were conducted with 392 low-income residents from Hartford and East Harford, Connecticut through a targeted sampling plan. We measured personal characteristics (income, education, use of crack, heroin, or cocaine in the last 6 months, receipt of welfare benefits, mental illness diagnosis, arrest, criminal conviction, longest prison term served, and self-reported HIV diagnosis); access to housing subsidies or supportive housing programs; current housing status; and sexual risk behaviors. To answer the aims above, we performed univariate analyses using Chi-square or 2-sided ANOVA's. Those with significance levels above (0.10) were included in multivariate analyses. We performed 2 separate multiple regressions to determine the effects of personal characteristics on access to housing subsidies and access to supportive housing respectively. We used multinomial main effects logistic regression to determine the effects of housing status on sexual risk behavior.</p> <p>Results</p> <p>Being HIV positive or having a mental illness predicted access to housing subsidies and supportive housing, while having a criminal conviction was not related to access to either housing subsidies or supportive housing. Drug use was associated with poorer housing statuses such as living on the street or in a shelter, or temporarily doubling up with friends, acquaintances or sex partners. Living with friends, acquaintances or sex partners was associated with greater sexual risk than those living on the street or in other stable housing situations.</p> <p>Conclusions</p> <p>Results suggest that providing low-income and supportive housing may be an effective structural HIV prevention intervention, but that the availability and accessibility of these programs must be increased.</p

Alcohol consumption and lifetime change in cognitive ability:a gene × environment interaction study

Studies of the effect of alcohol consumption on cognitive ability are often confounded. One approach to avoid confounding is the Mendelian randomization design. Here, we used such a design to test the hypothesis that a genetic score for alcohol processing capacity moderates the association between alcohol consumption and lifetime change in cognitive ability. Members of the Lothian Birth Cohort 1936 completed the same test of intelligence at age 11 and 70 years. They were assessed for recent alcohol consumption in later life and genotyped for a set of four single-nucleotide polymorphisms in three alcohol dehydrogenase genes. These variants were unrelated to late-life cognition or to socioeconomic status. We found a significant gene × alcohol consumption interaction on lifetime cognitive change (p = 0.007). Individuals with higher genetic ability to process alcohol showed relative improvements in cognitive ability with more consumption, whereas those with low processing capacity showed a negative relationship between cognitive change and alcohol consumption with more consumption. The effect of alcohol consumption on cognitive change may thus depend on genetic differences in the ability to metabolize alcohol

VEZF1 elements mediate protection from DNA methylation

There is growing consensus that genome organization and long-range gene regulation involves partitioning of the genome into domains of distinct epigenetic chromatin states. Chromatin insulator or barrier elements are key components of these processes as they can establish boundaries between chromatin states. The ability of elements such as the paradigm &#946;-globin HS4 insulator to block the range of enhancers or the spread of repressive histone modifications is well established. Here we have addressed the hypothesis that a barrier element in vertebrates should be capable of defending a gene from silencing by DNA methylation. Using an established stable reporter gene system, we find that HS4 acts specifically to protect a gene promoter from de novo DNA methylation. Notably, protection from methylation can occur in the absence of histone acetylation or transcription. There is a division of labor at HS4; the sequences that mediate protection from methylation are separable from those that mediate CTCF-dependent enhancer blocking and USF-dependent histone modification recruitment. The zinc finger protein VEZF1 was purified as the factor that specifically interacts with the methylation protection elements. VEZF1 is a candidate CpG island protection factor as the G-rich sequences bound by VEZF1 are frequently found at CpG island promoters. Indeed, we show that VEZF1 elements are sufficient to mediate demethylation and protection of the APRT CpG island promoter from DNA methylation. We propose that many barrier elements in vertebrates will prevent DNA methylation in addition to blocking the propagation of repressive histone modifications, as either process is sufficient to direct the establishment of an epigenetically stable silent chromatin stat