Mechanical properties of wool and cotton yarns used in twenty-first century tapestry: preparing for the future by understanding the present

The conservation of historic tapestries is a complex and highly skilled task. Tapestries now being woven will need conservation in years to come. Can we, by understanding the properties of these contemporary works, assist the conservators of the future? The recreation of the Hunt of the Unicorn tapestries being undertaken by the West Dean Tapestry Studio offers a unique opportunity to access the materials being used and to create a body of data on their initial properties. This study uses tensile testing of the warp and weft materials to determine their maximum load at break, extension at maximum load, and specific stress (tenacity). Wool weft yarns from two different sources and of two thicknesses were examined. These wools were dyed ‘in house’ and the effect of the different dyes used was also assessed. These parameters all showed some significant (P < 0.05) differences. Cotton warp yarns of differing thickness and a gold thread were also tested. The comparison of how cotton and wool break demonstrates that when a tapestry is put under sufficient stress the cotton will snap but the wool may only stretch. However, this could often be beyond its recovery range resulting in a failure to return to shape

Sexually transmitted infection testing and self-reported diagnoses among a community sample of men who have sex with men, in Scotland

Introduction To examine sexually transmitted infection (STI) testing and self-reported diagnoses among men who have sex with men (MSM), in Scotland. Methods Cross-sectional survey of seven Glasgow gay bars in July 2010 (n=822, 62% response rate); 693 are included in the analyses. Results 81.8% reported ever having had an STI test; 37.4% had tested in the previous 6 months; 13.2% reported having an STI in the previous 12 months. The adjusted odds of having ever tested were significantly higher for men who had 6+ sexual partners in the previous 12 months (adjusted OR=2.66), a maximum sexual health knowledge score (2.23), and had talked to an outreach worker/participated in counselling (1.96), and lower for men reporting any high-risk unprotected anal intercourse (UAI) in the previous 12 months (0.51). Adjusted odds of recent testing were higher for men who had 6+ sexual partners (2.10), talked to an outreach worker/participated in counselling (1.66), maximum sexual health knowledge (1.59), and higher condom use knowledge (1.04), and lower for men aged ≥25 years (0.46). Adjusted odds of having had an STI in the previous 12 months were higher for men who had 6+ sexual partners (3.96) and any high-risk UAI in the previous 12 months (2.24) and lower for men aged ≥25 years (0.57). Conclusions STI testing rates were relatively high, yet still below the minimum recommended for MSM at high risk. Consideration should be given to initiating recall systems for men who test positive for STIs, and to developing behavioural interventions which seek to address STI transmission

Has testing been normalized? An analysis of changes in barriers to HIV testing among men who have sex with men between 2000 and 2010 in Scotland, UK

Objectives: This paper examines changes in barriers to HIV testing amongst gay men. We compared data collected in 2000 and 2010 to assess changes in HIV testing behaviours, in community-level perceptions of barriers to HIV testing, and in the relative contributions of barrier measures. Methods: Cross-sectional surveys were conducted within the commercial gay scene in Glasgow with good response rates (78% and 62%) using a form of time and location sampling. Results: Major changes in HIV testing behaviours were observed between 2000 and 2010 (30.6% increase in testing within previous year). At the community level, the perceived benefits of testing [t (1284) = –8.46; P <0.001] and the norm for HIV testing [t (1236) = –11.62; P < 0.001] increased; however, other perceived barriers did not change (fear of a positive result, clinic-related barriers and attitudes to sex with HIV-positive men). Multinomial logistic regression showed that fear of a positive test result remained a key barrier to HIV testing; however, a significant fear × year of survey interaction indicated that fear played a lesser role in differentiating those who had never been tested from those who had been tested in 2010 than it had in 2000. Conclusions: These findings suggest the partial normalization of HIV testing. While some barriers have reduced, other key barriers remain important. Interventions should be designed and evaluated that attend to both the biomedical and the psychosocial aspects of HIV testing (e.g. the meaning of positive test results, the sexual exclusion of positive men, and HIV-related stigma)

Ranking of 11 coastal halophytes from salt marshes in northwest Turkey according their salt tolerance

Salt-affected soils with high electrolyte contents limit the development of the majority of plants and serve as a habitat only for such species (halophytes) that can survive the conditions. To date, there is still much that is unknown about the physiological mechanisms, including ion relationships, that make plants salt-resistant. The primary aim of this study was to evaluate a method of ranking plants for their salt tolerance. A total of 11 coastal halophytes of the Kavak Delta were evaluated for their ability to cope with different soil salinities. For this, electrical conductivities of soils (of up to 135 dS m(-1)) were recorded and a total of 100 plant samples, including plant roots, were taken from a depth of 0-15 cm in the soil. The halophytes were ranked in the following order from highest to moderate salt tolerance: Halocnemum strobilaceum >= Salicornia fragilis >= Arthrocnemum fruticosum = Suaeda prostrata >= Salsola kali = Petrosimonia brachiata >= Juncus maritimus = Aeluropus littoralis >= Halimione portulacoides = Limonium graecum >= Artemisia santonicum. The Na+/K+ ratios of leaves perfectly reflected the salinity tolerance ranking of all halophytic species examined. It proved possible to rank the salt tolerance of halophytes by assessment of the electrical conductivity of the soil in which they grew naturally; tolerance was well predicted by the Na+/K+ ratio in the shoots

Oscillatory subglacial drainage in the absence of surface melt

The presence of strong diurnal cycling in basal water pressure records obtained during the melt season is well established for many glaciers. The behaviour of the drainage system outside the melt season is less well understood. Here we present borehole observations from a surge-type valley glacier in the St Elias Mountains, Yukon Territory, Canada. Our data indicate the onset of strongly correlated multi-day oscillations in water pressure in multiple boreholes straddling a main drainage axis, starting several weeks after the disappearance of a dominant diurnal mode in August 2011 and persisting until at least January 2012, when multiple data loggers suffered power failure. Jökulhlaups provide a template for understanding spontaneous water pressure oscillations not driven by external supply variability. Using a subglacial drainage model, we show that water pressure oscillations can also be driven on a much smaller scale by the interaction between conduit growth and distributed water storage in smaller water pockets, basal crevasses and moulins, and that oscillations can be triggered when water supply drops below a critical value. We suggest this in combination with a steady background supply of water from ground water or englacial drainage as a possible explanation for the observed wintertime pressure oscillations

Fiber-Cavity-Based Optomechanical Device

We describe an optomechanical device consisting of a fiber-based optical cavity containing a silicon nitiride membrane. In comparison with typical free-space cavities, the fiber-cavity's small mode size (10 {\mu}m waist, 80 {\mu}m length) allows the use of smaller, lighter membranes and increases the cavity-membrane linear coupling to 3 GHz/nm and quadratic coupling to 20 GHz/nm^2. This device is also intrinsically fiber-coupled and uses glass ferrules for passive alignment. These improvements will greatly simplify the use of optomechanical systems, particularly in cryogenic settings. At room temperature, we expect these devices to be able to detect the shot noise of radiation pressure.Comment: 4 pages, 3 figures; the following article has been submitted to Applied Physics Letter

Colouring of Pacific barkcloth: identification of the brown, red and yellow colourants used in the decoration of historic Pacific barkcloths

Barkcloth textiles made in the Pacific islands and collected by western explorers in the eighteenth and nineteenth centuries form part of many museum collections worldwide. Here high-performance liquid chromatography (HPLC) and X-ray fluorescence (XRF) were used on cloths that were highly coloured or pigmented specifically focussing on identifying the red, yellow and brown colorants. The cloths studied came from collections held at the Hunterian, University of Glasgow, the Economic Botany Collection, Royal Botanic Gardens Kew and the Centre for Textile Conservation and Technical Art History, University of Glasgow. HPLC analysis was carried out following a sequential extraction procedure to minimise changes to the colorants during extraction. A portable XRF was used so no invasive sampling was required. A small number of plant derived colorants were found, Morinda citrifolia, noni (morindin or morindone), Rubia tinctorum (madder), tree tannins and Curcuma longa (turmeric) plus an inorganic colorant, iron oxide. For 40 samples a single colorant was found while in the remaining 12 samples combinations of up to three colorants were found. Madder was found in only 2 samples on the same cloth. The morindone coloured samples were all red whereas morindin samples were both red and yellow. Morindin was used predominantly in combination with other colouring agents. A combination of iron ochre and organic colorant was found in 4 samples. These findings show that despite the numerous potential colorant sources for red, brown and yellow shades listed in the many accounts of historic barkcloth making, only five types of plant colourant and one inorganic pigment were found. There are a number of potential reasons for these findings. Some colours may have faded and so no longer appear coloured. It is also possible that, as some of these cloths were prepared specifically as gifts for visitors or for ceremonial uses, the makers used materials that they knew would retain their integrity over time. Perhaps, like artisans worldwide, experience had taught them that some colorants, although initially bright and vivid, faded over time

Growth, Condition, and Trophic Relations of Stocked Trout in Southern Appalachian Mountain Streams

Stream trout fisheries are among the most popular and valuable in the United States, but many are dependent on hatcheries to sustain fishing and harvest. Thus, understanding the ecology of hatchery‐reared trout stocked in natural environments is fundamental to management. We evaluated the growth, condition, and trophic relations of Brook Trout Salvelinus fontinalis, Brown Trout Salmo trutta, and Rainbow Trout Oncorhynchus mykiss that were stocked in southern Appalachian Mountain streams in western North Carolina. Stocked and wild (naturalized) trout were sampled over time (monthly; September 2012–June 2013) to compare condition and diet composition and to evaluate temporal dynamics of trophic position with stable isotope analysis. Relative weights (Wr) of stocked trout were inversely associated with their stream residence time but were consistently higher than those of wild trout. Weight loss of harvested stocked trout was similar among species and sizes, but fish stocked earlier lost more weight. Overall, 40% of 141 stomachs from stocked trout were empty compared to 15% of wild trout stomachs (N = 26). We identified a much higher rate of piscivory in wild trout (18 times that of stocked trout), and wild trout were 4.3 times more likely to consume gastropods relative to stocked trout. Hatchery‐reared trout were isotopically similar to co‐occurring wild fish for both δ13C and δ15N values but were less variable than wild trout. Differences in sulfur isotope ratios (δ34S) between wild and hatchery‐reared trout indicated that the diets of wild fish were enriched in δ34S relative to the diets of hatchery‐reared fish. Although hatcheryreared trout consumed prey items similar to those of wild fish, differences in consumption or behavior (e.g., reduced feeding) may have resulted in lower condition and negative growth. These findings provide critical insight on the trophic dynamics of stocked trout and may assist in developing and enhancing stream trout fisheries