Tidal amplification of seabed light

Because solar irradiance decreases approximately exponentially with depth in the sea, the increase in irradiance at the seabed from mid to low tide is greater than the decrease from mid to high tide. Summed over a day, this can lead to a net amplification of seabed irradiance in tidal waters compared to nontidal waters with the same mean depth and transparency. In this paper, this effect is quantified by numerical and analytical integration of the Lambert-Beer equation to derive the ratio of daily total seabed irradiance with and without a tide. Greatest amplification occurs in turbid water with large tidal range and low tide occurring at noon. The theoretical prediction is tested against observations of seabed irradiance in the coastal waters of North Wales where tidal amplification of seabed light by up to a factor of 7 is both observed and predicted. Increasing the strength of tidal currents tends to increase the turbidity of the water and hence reduce the light reaching the seabed, but this effect is made less by increasing tidal amplification, especially when low water is in the middle of the day. The ecological implications of tidal amplification are discussed. The productivity of benthic algae will be greater than that predicted by simple models which calculate seabed irradiance using the mean depth of water alone. Benthic algae are also able to live at greater depths in tidal waters than in nontidal waters with the same transparency

An Exploration of Fetish Social Networks and Communities

Online Social Networks (OSNs) provide a venue for virtual interactions and relationships between individuals. In some communities, OSNs also facilitate arranging offline meetings and relationships. FetLife, the world’s largest anonymous social network for the BDSM, fetish and kink communities, provides a unique example of an OSN that serves as an interaction space, community organizing tool, and sexual market. In this paper, we present a first look at the characteristics of European members of Fetlife, comprising 504,416 individual nodes with 1,912,196 connections. We looked at user characteristics in terms of gender, sexual orientation, and preferred role. We further examined the homophilic communities and find that women in particular are far more platonically involved on the site than straight males. Our results suggest there are important differences between the FetLife community and conventional OSNs

Changes in microphytobenthos fluorescence over a tidal cycle: implications for sampling designs

Intertidal microphytobenthos (MPB) are important primary producers and provide food for herbivores in soft sediments and on rocky shores. Methods of measuring MPB biomass that do not depend on the time of collection relative to the time of day or tidal conditions are important in any studies that need to compare temporal or spatial variation, effects of abiotic factors or activity of grazers. Pulse amplitude modulated (PAM) fluorometry is often used to estimate biomass of MPB because it is a rapid, non-destructive method, but it is not known how measures of fluorescence are altered by changing conditions during a period of low tide. We investigated this experimentally using in situ changes in minimal fluorescence (F) on a rocky shore and on an estuarine mudflat around Sydney (Australia), during low tides. On rocky shores, the time when samples are taken during low tide had little direct influence on measures of fluorescence as long as the substratum is dry. Wetness from wave-splash, seepage from rock pools, run-off, rainfall, etc., had large consequences for any comparisons. On soft sediments, fluorescence was decreased if the sediment dried out, as happens during low-spring tides on particularly hot and dry days. Surface water affected the response of PAM and therefore measurements used to estimate MPB, emphasising the need for care to ensure that representative sampling is done during low tide

Detection of magnetic dipole lines of Fe XII in the ultraviolet spectrum of the dwarf star Epsilon Eri

We report observations of the dwarf star Epsilon Eri (K2 V) made with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope (HST). The high sensitivity of the STIS instrument has allowed us to detect the magnetic dipole transitions of Fe XII at 1242.00A and 1349.38A for the first time in a star other than the Sun. The width of the stronger line at 1242.00A has also been measured; such measurements are not possible for the permitted lines of Fe XII in the extreme ultraviolet. To within the accurcy of the measurements, the N V and the Fe XII lines occur at their rest wavelengths. Electron densities and line widths have been measured from other transition region lines. Together, these can be used to investigate the non-thermal energy flux in the lower and upper transition region, which is useful in constraining possible heating processes. The Fe XII lines are also present in archival STIS spectra of other G/K-type dwarfs.Comment: 12 pages, 4 figures, submitted to MNRAS letters (11 Jan 2001

Prevalence and risk factors for chronic edema in U.K. community nursing services

Background and study design: Chronic edema (CO) is believed to be a major clinical problem within community nursing services in the UK. This study was undertaken as part of the LIMPRINT international study to determine the number of people with chronic oedema and its impact on health services. Methods and Results: Three urban based community nursing services participated in the UK with prospective evaluation over 4 weeks of all patients receiving nursing care using a questionnaire-based interview and clinical assessment using the LIMPRINT tools. Of the total 2,541 assessed 1,440 (56.7%) were considered to have CO, comprising Leicester City (768/ 1298 (59.2%), Nottingham West (124/ 181 (68.5%)) and Nottingham City (548/1062 (51.6%)). The mean age for women with CO was 78.6 (SD 12.8) years and for men 72.9 (SD14.5). More patients with CO suffered from diabetes (32.1% versus 27.9%, p=0.027), heart failure/ ischaemic heart disease (27.3% versus 14.0%, p<0.001) and peripheral arterial occlusive disease (5.5% versus 1.9%, p<0.001). By far the greatest association was with the presence of a wound (73.6% versus 37.9%, p<0.001). Cellulitis affected 628 (24.7%) and 688 (47.8%) had a concurrent leg ulcer. Rates of reduced mobility (71.6% versus 61.9%) and obesity were higher in those with CO. Six independent factors associated with chronic oedema were service location, age, ethnicity, obesity, heart failure and the presence of a wound. Conclusion: Chronic oedema is a major and growing health care problem within primary care that has been previously unrecognised and requires effective service provision

Estimation of the prevalence of lymphoedema/chronic oedema in acute hospital in-patients

Background: To estimate the prevalence of lymphoedema/chronic oedema and wounds in acute hospital in-patients in 5 different countries. Method: A point-prevalence study was carried out during working day periods in six general hospitals in four countries (Denmark, France, United Kingdom, Australia) and one hospital oncology in-patient unit in one other country (Ireland). The study used validated clinical tools for the assessment and collection of data. Data were collected by expert clinicians through interviews and physical examination of the patients present in the wards. Results: A total of 1905 patients could be included and investigated among the 3041 total bed occupancy in the seven hospitals. Lymphoedema/chronic oedema was present in 723 of them (38%). Main risk factors associated with chronic oedema were age, morbid obesity and heart failure as well as chair bound immobility and neurological deficiency. History of cellulitis was frequent in patients with chronic oedema and wounds (24.8%), chronic oedema alone (14.1%) as compared to the 1.5% prevalence in patients without chronic oedema. Conclusion: Lymphoedema/chronic oedema is very frequent in patients hospitalized in hospital acute wards. It is strongly associated with obesity, venous insufficiency and heart failure. Our results strongly suggest a hidden health care burden and cost linked to chronic oedema independently of chronic wounds

IL28B, HLA-C, and KIR Variants Additively Predict Response to Therapy in Chronic Hepatitis C Virus Infection in a European Cohort: A Cross-Sectional Study

Vijayaprakash Suppiah and colleagues show that genotyping hepatitis C patients for the IL28B, HLA-C, and KIR genes improves the ability to predict whether or not patients will respond to antiviral treatment

Expression, localization and polymorphisms of the nuclear receptor PXR in Barrett's esophagus and esophageal adenocarcinoma

Background: The continuous exposure of esophageal epithelium to refluxate may induce ectopic expression of bile-responsive genes and contribute to the development of Barrett's esophagus (BE) and esophageal adenocarcinoma. In normal physiology of the gut and liver, the nuclear receptor Pregnane × Receptor (PXR) is an important factor in the detoxification of xenobiotics and bile acid homeostasis. This study aimed to investigate the expression and genetic variation of PXR in reflux esophagitis (RE), Barrett's esophagus (BE) and esophageal adenocarcinoma.Methods: PXR mRNA levels and protein expression were determined in biopsies from patients with adenocarcinoma, BE, or RE, and healthy controls. Esophageal cell lines were stimulated with lithocholic acid and rifampicin. PXR polymorphisms 25385C/T, 7635A/G, and 8055C/T were genotyped in 249 BE patients, 233 RE patients, and 201 controls matched for age and gender.Results: PXR mRNA levels were significantly higher in adenocarcinoma tissue and columnar Barrett's epithelium, compared to squamous epithelium of these BE patients (P < 0.001), and RE patients (P = 0.003). Immunohistochemical staining of PXR showed predominantly cytoplasmic expression in BE tissue, whereas nuclear expression was found in adenocarcinoma tissue. In cell lines, stimulation with lithocholic acid did not increase PXR mRNA levels, but did induce nuclear translocation of PXR protein. Genotyping of the PXR 7635A/G polymorphism revealed that the G allele was significantly more prevalent in BE than in RE or controls (P = 0.037).Conclusions: PXR expresses in BE and adenocarcinoma tissue, and showed nuclear localization in adenocarcinoma tissue. Upon stimulation with lithocholic acid, PXR translocates to the nuclei of OE19 adenocarcinoma cells. Together with the observed association of a PXR polymorphism and BE, this data implies that PXR may have a function in prediction and treatment of esophageal disease