Combined palaeolimnological and ecological approach provides added value for understanding the character and drivers of recent environmental change in Flow Country lakes

The Flow Country peatlands receive national and international recognition and protection as a highly valued habitat, and also provide a number of important ecosystem services. While there has been much research on the terrestrial peatland habitat of the Flow Country, the area’s many hundreds of natural water bodies have been largely unstudied. The first part of this study therefore focuses on establishing the contemporary conditions at 18 Flow Country lakes, examining between-lake heterogeneity in terms of physical structure, water chemistry and biological communities. Temporal change in these lakes is then considered by combining contemporary ecological and palaeolimnological approaches. We examine how the diatom and chironomid communities of Flow Country lakes have changed since a time prior to the mid-nineteenth century. Results show that the lake communities today are different to those present pre-1850, containing more taxa tolerant of increased acidity and nutrient availability. General linear modelling (GLM) analysis demonstrated a statistically significant association between the extent of change in diatom communities and both dissolved organic carbon (DOC) and nitrate. Community shifts, though considerable, are shown to be complex and idiosyncratic and no shift between trophic states is indicated. The extent and type of coarse-scale community change we observed points to widespread bottom-up drivers such as land management, afforestation and/or atmospheric deposition rather than more localised management practices such as fish stocking. The benefits of combining approaches is discussed and palaeolimnological methods by which land management, afforestation and atmospheric deposition could be further disentangled are identified

Borrowing from the palaeolimnologists toolkit; the use of lake sediment cores in diagnosing the causes of freshwater species decline

Populations of freshwater species are experiencing dramatic declines globally. Tools that facilitate the diagnosis of decline and identify management solutions and/or restoration targets are thus vital. Typically approaches taken to diagnose decline are carried out over short timescales and rely upon identifying spatial associations between presence or abundance of declining species and variables hypothesised to be driving decline. The potential to contextualise observed declines on longer time scales, with a broader range of potential explanatory variables is frequently dismissed, because of a perceived lack of existing long-term data. In this study we explore the value of incorporating a longer-term perspective to decline diagnosis using the common scoter as a case study. The number of scoter breeding in Scotland has declined substantially since the 1970s. Hypotheses for decline include a reduction in macroinvertebrate food available for females and young at the breeding lakes. In this study we apply palaeolimnological techniques to generate standardised, long-term ecological data, enabling us to characterise recent changes at four common scoter breeding lakes. Our results demonstrate that the (macroinvertebrate) food resource of common scoter has, in fact, gradually increased in abundance at all four sites from ca. 1900, and that a further statistically significant increase in macroinvertebrate abundance occurred at ca. 1970. We draw on our palaeolimnological data, to explore alternative hypotheses for common scoter decline. Increases in overall abundance across multiple algal, macrophyte and macroinvertebrate taxa, combined with specific increases in nutrient tolerant taxa, and concurrent declines in nutrient sensitive taxa indicate that the lakes have experienced enrichment within their current oligotrophic state during the last 100 years, and that this trajectory has become more marked during the period of common scoter decline. There is no evidence of changes to habitat, turbidity or increased competition from fish. In the absence of within lake changes that could be detrimental to the benthic (and generalist) feeding common scoter, we conclude that factors outside of the lake, such as increased predation, associated with afforestation in the surrounding area, are the most plausible drivers of common scoter decline. Prioritisation/testing of management solutions that address these issues are indicated

Pond management enhances the local abundance and species richness of farmland bird communities

Agricultural intensification and the associated loss of non-cropped habitats have caused a major decline in UK farmland bird populations since the 1970s. As a consequence, there is an urgent need to implement effective conservation and habitat restoration measures in agricultural landscapes. Over the last 40–50 years, due to the cessation of traditional management practices, the majority of UK farmland ponds have become highly terrestrialised, resulting in major reductions in the diversity and abundance of aquatic plant and invertebrate assemblages. Recent research undertaken at farmland ponds in early summer, has shown restored open-canopy, macrophyte-dominated ponds support an increased abundance and diversity of farmland birds, compared to non-managed, overgrown ponds. Here, we expand on this previous research with a year-long field study to assess the implications of pond management for farmland birds by comparing bird diversity, abundance and activity at managed open-canopy ponds with those at unmanaged overgrown ponds. Driven strongly by pond management and connectivity to semi-natural landscape features such as hedgerows and woodland patches, bird abundance and species richness, as well as foraging and parental behaviour, were all significantly higher at managed open-canopy ponds. Further, a wider landscape analysis found that terrestrial land-use patterns in the vicinity of the ponds were not significant predictors of bird communities at the pond sites. In light of the numerous potential benefits to conservation-listed birds and other wildlife, we conclude that farmland pond management has been undervalued as a conservation measure to assist farmland birds. Consequently, we conclude that future agri-environment schemes, should more fully embrace farmland ponds

Performance of Risk-Based Criteria for Targeting Acute HIV Screening in San Francisco

Federal guidelines now recommend supplemental HIV RNA testing for persons at high risk for acute HIV infection. However, many rapid HIV testing sites do not include HIV RNA or p24 antigen testing due to concerns about cost, the need for results follow-up, and the impact of expanded venipuncture on clinic flow. We developed criteria to identify patients in a municipal STD clinic in San Francisco who are asymptomatic but may still be likely to have acute infection.Data were from patients tested with serial HIV antibody and HIV RNA tests to identify acute HIV infection. BED-CEIA results were used to classify non-acute cases as recent or longstanding. Demographics and self-reported risk behaviors were collected at time of testing. Multivariate models were developed and preliminarily evaluated using predictors associated with recent infection in bivariate analyses as a proxy for acute HIV infection. Multivariate models demonstrating ≥70% sensitivity for recent infection while testing ≤60% of patients in this development dataset were then validated by determining their performance in identifying acute infections.From 2004-2007, 137 of 12,622 testers had recent and 36 had acute infections. A model limiting acute HIV screening to MSM plus any one of a series of other predictors resulted in a sensitivity of 83.3% and only 47.6% of patients requiring testing. A single-factor model testing only patients reporting any receptive anal intercourse resulted in 88.9% sensitivity with only 55.2% of patients requiring testing.In similar high risk HIV testing sites, acute screening using "supplemental" HIV p24 antigen or RNA tests can be rationally targeted to testers who report particular HIV risk behaviors. By improving the efficiency of acute HIV testing, such criteria could facilitate expanded acute case identification

Large woody debris "rewilding" rapidly restores biodiversity in riverine food webs

Extensive habitat destruction and pollution have caused dramatic declines in aquatic biodiversity at local to global scales. In rivers, the reintroduction of large woody debris is a common method aimed at restoring degraded ecosystems through "rewilding." However, causal evidence for its effectiveness is lacking due to a dearth of replicated before-after control-impact field experiments. We conducted the first replicated experiment of large woody debris rewilding across multiple rivers and organisational levels, from individual target species populations to entire food webs. For the first time, we demonstrate causal links between habitat restoration, biodiversity restoration and food web responses. Populations of invertebrates and an apex predator, brown trout (Salmo trutta), increased, and food web analysis suggested increased biomass flux from basal resources to invertebrates and subsequently fishes within restored reaches. Synthesis and applications. This study contributes significant new evidence demonstrating that large woody debris rewilding can help to restore human-impacted river ecosystems, primarily through altering the abundance and biomass of consumers and resources in the food web. We also outline a means to gauge the magnitude of ecological responses to restoration, relative to environmental stressors, which could help to prioritise the most effective conservation efforts

Inhibition of the tyrosine phosphatase SHP-2 suppresses angiogenesis in vitro and in vivo

Endothelial cell survival is indispensable to maintain endothelial integrity and initiate new vessel formation. We investigated the role of SHP-2 in endothelial cell survival and angiogenesis in vitro as well as in vivo. SHP-2 function in cultured human umbilical vein and human dermal microvascular endothelial cells was inhibited by either silencing the protein expression with antisense-oligodesoxynucleotides or treatment with a pharmacological inhibitor (PtpI IV). SHP-2 inhibition impaired capillary-like structure formation (p < 0.01; n = 8) in vitro as well as new vessel growth ex vivo (p < 0.05; n = 10) and in vivo in the chicken chorioallantoic membrane (p < 0.01, n = 4). Additionally, SHP-2 knock-down abrogated fibroblast growth factor 2 (FGF-2)-dependent endothelial proliferation measured by MTT reduction ( p ! 0.01; n = 12). The inhibitory effect of SHP-2 knock-down on vessel growth was mediated by increased endothelial apoptosis ( annexin V staining, p ! 0.05, n = 9), which was associated with reduced FGF-2-induced phosphorylation of phosphatidylinositol 3-kinase (PI3-K), Akt and extracellular regulated kinase 1/2 (ERK1/2) and involved diminished ERK1/2 phosphorylation after PI3-K inhibition (n=3). These results suggest that SHP-2 regulates endothelial cell survival through PI3-K-Akt and mitogen-activated protein kinase pathways thereby strongly affecting new vessel formation. Thus, SHP-2 exhibits a pivotal role in angiogenesis and may represent an interesting target for therapeutic approaches controlling vessel growth. Copyright (C) 2007 S. Karger AG, Basel

Intermittent control models of human standing: similarities and differences

Two architectures of intermittent control are compared and contrasted in the context of the single inverted pendulum model often used for describing standing in humans. The architectures are similar insofar as they use periods of open-loop control punctuated by switching events when crossing a switching surface to keep the system state trajectories close to trajectories leading to equilibrium. The architectures differ in two significant ways. Firstly, in one case, the open-loop control trajectory is generated by a system-matched hold, and in the other case, the open-loop control signal is zero. Secondly, prediction is used in one case but not the other. The former difference is examined in this paper. The zero control alternative leads to periodic oscillations associated with limit cycles; whereas the system-matched control alternative gives trajectories (including homoclinic orbits) which contain the equilibrium point and do not have oscillatory behaviour. Despite this difference in behaviour, it is further shown that behaviour can appear similar when either the system is perturbed by additive noise or the system-matched trajectory generation is perturbed. The purpose of the research is to come to a common approach for understanding the theoretical properties of the two alternatives with the twin aims of choosing which provides the best explanation of current experimental data (which may not, by itself, distinguish beween the two alternatives) and suggesting future experiments to distinguish between the two alternatives

Activation of Latent HIV Using Drug-Loaded Nanoparticles

Antiretroviral therapy is currently only capable of controlling HIV replication rather than completely eradicating virus from patients. This is due in part to the establishment of a latent virus reservoir in resting CD4+ T cells, which persists even in the presence of HAART. It is thought that forced activation of latently infected cells could induce virus production, allowing targeting of the cell by the immune response. A variety of molecules are able to stimulate HIV from latency. However no tested purging strategy has proven capable of eliminating the infection completely or preventing viral rebound if therapy is stopped. Hence novel latency activation approaches are required. Nanoparticles can offer several advantages over more traditional drug delivery methods, including improved drug solubility, stability, and the ability to simultaneously target multiple different molecules to particular cell or tissue types. Here we describe the development of a novel lipid nanoparticle with the protein kinase C activator bryostatin-2 incorporated (LNP-Bry). These particles can target and activate primary human CD4+ T-cells and stimulate latent virus production from human T-cell lines in vitro and from latently infected cells in a humanized mouse model ex vivo. This activation was synergistically enhanced by the HDAC inhibitor sodium butyrate. Furthermore, LNP-Bry can also be loaded with the protease inhibitor nelfinavir (LNP-Bry-Nel), producing a particle capable of both activating latent virus and inhibiting viral spread. Taken together these data demonstrate the ability of nanotechnological approaches to provide improved methods for activating latent HIV and provide key proof-of-principle experiments showing how novel delivery systems may enhance future HIV therapy

Does a SLAP lesion affect shoulder muscle recruitment as measured by EMG activity during a rugby tackle?

Background: The study objective was to assess the influence of a SLAP lesion on onset of EMG activity in shoulder muscles during a front on rugby football tackle within professional rugby players. Methods: Mixed cross-sectional study evaluating between and within group differences in EMG onset times. Testing was carried out within the physiotherapy department of a university sports medicine clinic. The test group consisted of 7 players with clinically diagnosed SLAP lesions, later verified on arthroscopy. The reference group consisted of 15 uninjured and full time professional rugby players from within the same playing squad. Controlled tackles were performed against a tackle dummy. Onset of EMG activity was assessed from surface EMG of Pectorialis Major, Biceps Brachii, Latissimus Dorsi, Serratus Anterior and Infraspinatus muscles relative to time of impact. Analysis of differences in activation timing between muscles and limbs (injured versus non-injured side and non injured side versus matched reference group). Results: Serratus Anterior was activated prior to all other muscles in all (P = 0.001-0.03) subjects. In the SLAP injured shoulder Biceps was activated later than in the non-injured side. Onset times of all muscles of the noninjured shoulder in the injured player were consistently earlier compared with the reference group. Whereas, within the injured shoulder, all muscle activation timings were later than in the reference group. Conclusions: This study shows that in shoulders with a SLAP lesion there is a trend towards delay in activation time of Biceps and other muscles with the exception of an associated earlier onset of activation of Serratus anterior, possibly due to a coping strategy to protect glenohumeral stability and thoraco-scapular stability. This trend was not statistically significant in all cases