Approaches to the Design of Biotechnical Streambank Stabilization: Volume I—A Guide to the Literature

Streambank stabilization has traditionally been performed with riprap for which reliable design and installation procedures are available. Due to concerns about the environmental impact of riprap, there has been increasing interest in more natural biotechnical (or bioengineering) alternatives. A review of the litera­ture on biotechnical approaches to streambank stabilization has been per­formed, with a focus on those works that might be particularly useful in developing design guidelines or standards for the Indiana Department of Transportation. Works that synthesized the literature (up to about the year 2000) and so covered a broad range of topics, were examined, including monographs and manuals published by federal and state agencies. More recent publications were also found on narrower more specific topics, including the ecological effects of riprap and bio­technical approaches, advances in the geotechnical modeling of vegetation effects on bank stability, the effectiveness of biotechnical measures, and screening methods for selecting appropriate measures. Implications of the reviewed work for the development of design guidelines are discussed

Approaches to the Design of Biotechnical Streambank Stabilization: Volume III—Design Guidelines

A conceptual framework for the design of biotechnical streambank revetment is proposed. It is intended to be simple in practice, flexible in being widely applicable, familiar in retaining cer­tain aspects of current practice while being patterned after other aspects, and encouraging a more environmentally sensitive approach to reliable streambank protection for INDOT projects. It distinguishes between a toe zone, where traditional hard armoring techniques such as those already included in the INDOT standard designs are more appropriate, and an upper bank zone where vegetation-based techniques would typically be applied. Default techniques are identified to simplify the choice of measures for \u27routine\u27 problems, but more case-specific techniques may also be selected. Primary techniques that offer immediate protection on their own are also distin­guished from supplementary techniques that are used only in combination with other (primary) techniques. The boundary between the toe zone and the upper bank zone is proposed to be the maximum of the ordinary high water mark (or bankfull elevation), the elevation corresponding to the 2-year discharge, and the elevation corresponding to the point that is one third up the slope from the bank toe at the design discharge (for streambank protection). For the upper bank zone, for bank slopes up to 2H:1V, regrading and revegetation with herbaceous species together with the use of rolled erosion control products (RECPs) is proposed as the default. The other (non-default) main primary technique for the upper bank zone is the vegetated mechanically stabilized earth (VMSE, or vegetated reinforced soil slope VRSS, or soil lifts) option (where revegetation with herbaceous species is also considered standard). This requires more engineering and construct­ion effort but is appropriate for those projects where a more vertical (up to maximum bank slope of 1H:1V) solution is desired. The supplementary techniques to be included are live staking to be used with the regrading option, and brush-layering to be used with the VMSE option

Approaches to the Design of Biotechnical Streambank Stabilization: Volume II—A Field Assessment

As part of a larger project to develop guidelines for the design of biotechnical approaches to streambank stabilization to be included in INDOT standard designs and specifications, a field assessment was undertaken of 26 sites, of which 13 were INDOT sites. Multiple techniques were frequently installed in combination, which resulted in 47 samples of 12 different techniques at the 26 sites. Each site was visited at least once and the measures were visually inspected for evi­dence of damage either to the measure or to the streambank being protected. Some of the field assessments were supplemented by interviews with designers involved in the INDOT projects; the general merits of biotechnical techniques were discussed together with those of specific tech­niques that might be included in a standard design. The assessment resulted in grouping the techniques into three broad categories: i) typically reliable techniques that could be used where tolerance for bank instability is very low, and generally involving hard armor, ii) potentially reliable techniques where the tolerance for bank instability is low to moderate, and iii) techniques that are appropriate only for special circumstances or to be used only in combination with measures from the other two groups

Sulphur-isotope compositions of pig tissues from a controlled feeding study

Sulphur-isotope determinations are becoming increasingly useful for palaeodietary reconstruction, but knowledge of isotopic discrimination between diet and various tissues remains inadequate. In this study, we explore the sensitivity of δ34Stissue values to changes in δ34Sdiet values, sulphur isotopic discrimination between diet and consumer, and the potential impact of terrestrial vs. marine protein consumption on these discrimination offsets. We present new δ34S values of bone collagen, muscle, liver, hair, milk and faeces from ten mature sows, ten piglets and fifteen adolescent pigs from a controlled feeding study. The δ34Stissue values were found to co-vary with the δ34Sdiet values, the δ34Stissue – δ34Sdiet isotopic offsets (Δ34Stissue-diet) are small but consistent, and dietary protein source does not systematically alter the Δ34Stissue-diet isotopic discrimination. The outcomes of this study are of particular relevance to questions that are difficult to resolve using carbon and nitrogen stable isotopes alone, and will also be useful in regions where terrestrial, freshwater, and marine resources could have all potentially contributed to human diet

Helicobacter pylori and cancer among adults in Uganda

Data from Africa on infection with Helicobacter pylori (H. pylori) are sparse. Therefore, as part of an epidemiological study of cancer in Uganda, we investigated the prevalence and determinants of antibodies against H. pylori among 854 people with different cancer types and benign tumours. Patients were recruited from hospitals in Kampala, Uganda, interviewed about various demographic and lifestyle factors and tested for antibodies against H. pylori. In all patients combined, excluding those with stomach cancer (which has been associated with H. pylori infection), the prevalence of antibodies was 87% (723/833) overall, but declined with increasing age (p = 0.02) and was lower among people who were HIV seropositive compared to seronegative (p <0.001). Otherwise, there were few consistent epidemiological associations. Among those with stomach cancer, 18/21 (86%) had anti-H. pylori antibodies (odds ratio 0.8, 95% confidence intervals 0.2–2.9, p = 0.7; estimated using all other patients as controls, with adjustment for age, sex and HIV serostatus). No other cancer site or type was significantly associated with anti-H. pylori antibodies. The prevalence of H. pylori reported here is broadly in accord with results from other developing countries, although the determinants of infection and its' role in the aetiology of gastric cancer in Uganda remain unclear

Collaborative Community Health Needs Assessments: Approaches and Benefits for Critical Access Hospitals (FMT Policy Brief #36)

The primary purpose of this brief is to inform the efforts of state Flex Programs to support CAHs in conducting collaborative Community Health Needs Assessments (CHNAs). The results of these assessments can be used by hospitals as well as state Flex Programs to inform their ongoing strategic initiatives. Key Findings: Small hospitals and communities can successfully collaborate on CHNAs. Collaborative CHNAs can serve as building blocks for a more comprehensive community health improvement strategy. Data requirements for the community assessment obligations of CAHs, rural hospitals, public health departments, and community providers offer a key opportunity for collaboration and economies of scale in collecting and analyzing needed primary and secondary data. Collaboration requires the development of trust and rapport among participants; the acknowledgement and management of imbalances of leadership, power, and resources; and recognition of each participant’s assessment needs. Collaborative CHNAs can provide a foundation to engage diverse hospital, public health and other community stakeholders in the development of strategies to address identified community needs

Optically Thin Metallic Films for High-radiative-efficiency Plasmonics

Plasmonics enables deep-subwavelength concentration of light and has become important for fundamental studies as well as real-life applications. Two major existing platforms of plasmonics are metallic nanoparticles and metallic films. Metallic nanoparticles allow efficient coupling to far field radiation, yet their synthesis typically leads to poor material quality. Metallic films offer substantially higher quality materials, but their coupling to radiation is typically jeopardized due to the large momentum mismatch with free space. Here, we propose and theoretically investigate optically thin metallic films as an ideal platform for high-radiative-efficiency plasmonics. For far-field scattering, adding a thin high-quality metallic substrate enables a higher quality factor while maintaining the localization and tunability that the nanoparticle provides. For near-field spontaneous emission, a thin metallic substrate, of high quality or not, greatly improves the field overlap between the emitter environment and propagating surface plasmons, enabling high-Purcell (total enhancement > $10^4$), high-quantum-yield (> 50 %) spontaneous emission, even as the gap size vanishes (3$\sim$5 nm). The enhancement has almost spatially independent efficiency and does not suffer from quenching effects that commonly exist in previous structures.Comment: Supporting Information not included but freely available from DOI:10.1021/acs.nanolett.6b0085

Scattering states of coupled valence-band holes in point defect potential derived from variable phase theory

In this article we present a method to compute the scattering states of holes in spherical bands in the strong spin-orbit coupling regime. More precisely, we calculate scattering phase shifts and amplitudes of holes induced by defects in a semiconductor crystal. We follow a previous work done on this topic by Ralph [H. I. Ralph, Philips Res. Rept. 32 160 (1977)] to account for the p-wave nature and the coupling of valence band states. We extend Ralph's analysis to incorporate finite-range potentials in the scattering problem. We find that the variable phase method provides a very convenient framework for our purposes and show in detail how scattering amplitudes and phase shifts are obtained. The Green's matrix of the Schroedinger equation, the Lippmann-Schwinger equation and the Born approximation are also discussed. Examples are provided to illustrate our calculations with Yukawa type potentials.Comment: 16 pages and 9 figure

Causes and Consequences of Broad-Scale Changes in the Distribution of Migratory Caribou (Rangifer tarandus) of Southern Hudson Bay

Understanding the factors driving changes in species distributions is fundamental to conservation, but for wide-ranging species this is often complicated by the need for broad-scale observations across space and time. In the last three decades, the location of summer concentrations of migratory caribou (Rangifer tarandus) in southern Hudson Bay (SHB), Canada, has shifted south and east as much as 500 km. We used long-term data (1987 – 2011) to test two hypotheses that could explain the distribution shift: forage depletion and anthropogenic disturbance. Over time and space, we compared the body size of live-captured adult female caribou, dietary quality from fecal nitrogen in July, the location of VHF- and GPS-collared female caribou in July, distribution of all-terrain vehicle (ATV) tracks and caribou tracks in August, and the proximity of collared caribou to sections of the coast with higher ATV activity in spring and summer. The forage depletion hypothesis was supported by greater body size and dietary quality in caribou of the eastern portion of SHB than in western SHB animals in 2009 – 11. The anthropogenic disturbance hypothesis was supported by the negative correlation of the distributions of ATV tracks and caribou tracks on the coast in 2010 and the fact that caribou avoided areas with ATV activity by 10 – 14 km. In 1987, collared caribou were observed largely along the coast in western SHB in mid-July, while in 2009 – 11, they were inland in western SHB and along the coast in eastern SHB. While these locations demonstrate a substantial change in summer distri­bution over three decades, we were unable to differentiate between forage depletion and anthropogenic disturbance as a single causal factor of the distribution shift.La compréhension des facteurs qui influencent les changements caractérisant les distributions des espèces est fondamentale aux efforts de conservation, mais pour les espèces dont l’aire de distribution est étendue, ce principe est souvent compliqué par la nécessité de faire des observations à grande échelle, dans le temps et dans l’espace. Au cours des trois dernières décennies, l’emplacement des concentrations estivales du caribou migrateur (Rangifer tarandus) dans le sud de la baie d’Hudson (SBH), au Canada, s’est déplacé vers le sud et vers l’est dans une mesure de 500 km. Nous nous sommes appuyés sur des données de longue haleine (1987–2011) pour mettre à l’épreuve deux hypothèses susceptibles d’expliquer ce changement en matière de distribution, soit l’appauvrissement du fourrage et la perturbation anthropique. Au fil du temps et de l’espace, nous avons comparé la taille du corps des caribous femelles adultes capturées vivantes, la qualité de leur alimentation à partir de l’azote fécal en juillet, l’emplacement des femelles portant un collier de type VHF ou GPS en juillet, la répartition des traces de véhicules tout terrain (VTT) et des pistes de caribou en août de même que la proximité des caribous portant un collier aux tronçons de la côte où la présence de VTT est plus grande au printemps et à l’été. L’hypothèse de l’appauvrissement du fourrage a été étayée par la plus grande taille du corps et la qualité de l’alimentation du caribou de la zone est du SBH comparativement à celles du caribou de l’ouest du SBH entre 2009 et 2011. Pour sa part, l’hypothèse perturbation anthropique a été appuyée par la corrélation négative caractérisant la répartition des pistes de VTT et des traces de caribou sur la côte en 2010 et par le fait que les caribous sont restés à l’écart des zones fréquentées par les VTT dans une mesure de 10 à 14 km. En 1987, des caribous portant un collier ont été observés en grand nombre le long de la côte ouest du SBH à la mi-juillet, tandis que de 2009 à 2011, ils ont été repérés à l’intérieur des terres dans l’ouest du SBH et le long de la côte est du SBH. Bien que ces emplacements indiquent un important changement en matière de distribution estivale au cours de trois décennies, nous n’avons pas été en mesure de faire une distinction entre l’appauvrissement du fourrage et la perturbation anthropique en tant que facteur causal unique du changement de distribution