The significance and provenance of stromatolitic clasts in a probable Late Precambrian diamictite in north-western Tasmania

Two types of stromatolitic dolomite boulders occur in a diamictite of possibly late Precambrian age in northwestern Tasmania; they are the oldest Tasmanian fossils so far recorded. The first type comprises dark grey dolomites containing the stromatolite Baicalia cf. B. burra, generally well preserved. The remainder are pale grey rather recrystallised dolomites containing stratiform and columnar-layered stromatolites. Their diagenesis and intrusion by dolomite veins preceded the erosion and redeposition of the clasts into the diamictite. The diamictite contains no diagnostic evidence of glaciation though a glacial origin cannot be definitely excluded. A debris flow mechanism of deposition is favoured. There is no proof in the material examined that either the well preserved Baicalia specimens or the recrystallised stromatolitic dolomites, occurring in clasts in the diamictite, were derived from the Smithton Dolomite. The occurrence of Baicalia cf. B. burra is consistent with a late Precambrian age of the source rocks, and close comparisons can be made with the Skillogalee Dolomite of South Australia

Erosion and rabbits on Macquarie Island: some comments

Rapid emergence and subsequent glacial and periglacial action on Macquarie Island have placed it in a state of high erosional activity. The dominant processes are mass erosion through landslips, soil creep slumping and solifluction. Fluvial and aeolian erosion are only important in very restricted areas. Rabbit activity has had a minimal effect on the overall rates of erosion although appearing significant in some localised areas

Hegemonic masculinity as a historical problem

This article reaffirms the importance of gender history as a way of understanding the history of power, and specifically power relations between men and masculinities. The historical literature dealing with this theme has been profoundly shaped by R. W. Connell’s concept of ‘hegemonic masculinity’. Despite detailed criticism by historians, Connell’s work remains enormously influential on historical scholarship because no alternative model has delineated so clearly the significance of power relations between masculinities. This article offers a critical reading of Connell’s work and develops a new analytical framework for understanding the history of masculinity. It argues that histories of normative models of masculinity need to be accompanied by a focus on the historically specific opportunities, mechanisms or techniques that enabled individuals to identify themselves with particular normative models. It argues that power can be apprehended as a four-fold operation: cultural contestation of normative ideals; individual attempts to identify with those cultural ideals; the processes by which those attempts were accorded recognition by others; and the processes by which individuals were positioned in relation to institutional practices, rewards and sanctions. This approach would offer new periodisations of the history of masculinity with the history of power at their core

Effectiveness and cost effectiveness of pharmacological thromboprophylaxis for medical inpatients: decision analysis modelling study.

OBJECTIVE: To determine the balance of costs, risks, and benefits for different thromboprophylaxis strategies for medical patients during hospital admission. DESIGN: Decision analysis modelling study. SETTING: NHS hospitals in England. POPULATION: Eligible adult medical inpatients, excluding patients in critical care and pregnant women. INTERVENTIONS: Pharmacological thromboprophylaxis (low molecular weight heparin) for all medical inpatients, thromboprophylaxis for none, and thromboprophylaxis given to higher risk inpatients according to risk assessment models (Padua, Caprini, IMPROVE, Intermountain, Kucher, Geneva, and Rothberg) previously validated in medical cohorts. MAIN OUTCOME MEASURES: Lifetime costs and quality adjusted life years (QALYs). Costs were assessed from the perspective of the NHS and Personal Social Services in England. Other outcomes assessed were incidence and treatment of venous thromboembolism, major bleeds including intracranial haemorrhage, chronic thromboembolic complications, and overall survival. RESULTS: Offering thromboprophylaxis to all medical inpatients had a high probability (>99%) of being the most cost effective strategy (at a threshold of £20 000 (€23 440; $25 270) per QALY) in the probabilistic sensitivity analysis, when applying performance data from the Padua risk assessment model, which was typical of that observed across several risk assessment models in a medical inpatient cohort. Thromboprophylaxis for all medical inpatients was estimated to result in 0.0552 additional QALYs (95% credible interval 0.0209 to 0.1111) while generating cost savings of £28.44 (-£47 to £105) compared with thromboprophylaxis for none. No other risk assessment model was more cost effective than thromboprophylaxis for all medical inpatients when assessed in deterministic analysis. Risk based thromboprophylaxis was found to have a high (76.6%) probability of being the most cost effective strategy only when assuming a risk assessment model with very high sensitivity is available (sensitivity 99.9% and specificity 23.7% v base case sensitivity 49.3% and specificity 73.0%). CONCLUSIONS: Offering pharmacological thromboprophylaxis to all eligible medical inpatients appears to be the most cost effective strategy. To be cost effective, any risk assessment model would need to have a very high sensitivity resulting in widespread thromboprophylaxis in all patients except those at the very lowest risk, who could potentially avoid prophylactic anticoagulation during their hospital stay

Fiber-optic chemical sensors for competitive binding fluoroimmunoassay

This paper describes the development of a fiber-optic chemical sensor based on the principle of competitive-binding fluorescence immunoassay. Rabbit immunoglobln G (IgG) is covalently Immobilized on the distal sensing tip of a quartz optical fiber. The sensor is exposed to fluorescein Isothiocyanate (FITC) labeled and unlabeled anti-rabbit IgG. The 488-nm line of an argon-ion laser provides excitation of sensor-bound analyte. This results in fluorescence emission at the optical fiber‧s sensing tip. Sensor response is inversely proportional to the amount of unlabeled anti-IgG In the sample. Limits of detection (LOD) vary with Incubation time, sample size, and measurement conditions. For 10-μL samples, typical LOD are 25 fmol of unlabeled antibody In a 20-min Incubation period. These results Indicate that each fiber-optic fluoroimmunosensor can be constructed to perform a single sensitive, rapid, low-volume immunoassay, in in situ or benchtop applications. © 1987, American Chemical Society. All rights reserved

Electrical stimulation devices for the prevention of venous thromboembolism: Preliminary studies of physiological efficacy and user satisfaction.

Introduction: Electrical stimulation could provide an alternative method for preventing venous thromboembolism in stroke patients. The purpose of this preliminary study was to explore the effects of electrical stimulation and intermittent pneumatic compression on enhancing lower limb venous return in healthy and chronic stroke patients and also to evaluate patient and nurse satisfaction. Methods: We investigated the effectiveness of two electrical stimulation devices: Geko (Firstkind Ltd, High Wycombe, UK) and Orthopaedic Microstim 2V2 (Odstock Medical Ltd, Salisbury, UK); and one intermittent pneumatic compression device: Huntleigh Flowstron Universal (Huntleigh Healthcare Ltd, Cardiff, UK). We recruited 12 healthy and 5 chronic stroke participants. The devices were fitted sequentially, and Doppler ultrasound measurements were taken. Eight patients and nurses were also recruited for a separate usability evaluation. Results: The electrical stimulation devices emulated the blood flow characteristics of intermittent pneumatic compression in both healthy and stroke participants provided that the intensity of electrical stimulation was sufficient. Patients and nurses also felt that the electrical stimulation devices were acceptable. Conclusions: Electrical stimulation may offer benefit as an alternative method for venous thromboembolism prevention in stroke patients. The apparent benefit is sufficient to warrant further investigation in a full powered randomised controlled trial

Evaluating the landscape of fear between apex predatory sharks and mobile sea turtles across a large dynamic seascape

The ‘‘landscape of fear’’ model has been proposed as a unifying concept in ecology, describing, in part, how animals behave and move about in their environment. The basic model predicts that as an animal’s landscape changes from low to high risk of predation, prey species will alter their behavior to risk avoidance. However, studies investigating and evaluating the landscape of fear model across large spatial scales (tens to hundreds of thousands of square kilometers) in dynamic, open, aquatic systems involving apex predators and highly mobile prey are lacking. To address this knowledge gap, we investigated predator–prey relationships between tiger sharks (Galeocerdo cuvier) and loggerhead turtles (Caretta caretta) in the North Atlantic Ocean. This included the use of satellite tracking to examine shark and turtle distributions as well as their surfacing behaviors under varying levels of home range overlap. Our findings revealed patterns that deviated from our a priori predictions based on the landscape of fear model. Specifically, turtles did not alter their surfacing behaviors to risk avoidance when overlap in shark–turtle core home range was high. However, in areas of high overlap with turtles, sharks exhibited modified surfacing behaviors that may enhance predation opportunity. We suggest that turtles may be an important factor in determining shark distribution, whereas for turtles, other life history trade-offs may play a larger role in defining their habitat use. We propose that these findings are a result of both biotic and physically driven factors that independently or synergistically affect predator–prey interactions in this system. These results have implications for evolutionary biology, community ecology, and wildlife conservation. Further, given the difficulty in studying highly migratory marine species, our approach and conclusions may be applied to the study of other predator–prey systems.Bald Head Island ConservancyBritish Chelonia GroupNatural Environmental Research CouncilWAVE Foundation/Newport Aquarium CincinnatiPADI project AWARESEATURTLE.ORGWhitener Foundation (NC); an Endangered Species Act Section 6 Cooperative Agreement with NOAA Fisheries and the Grays Reef National Marine Sanctuary (South Carolina and Georgia)Batchelor FoundationDinsey Conservation Fun

How Firms Adapt and Interact in Open Source Ecosystems: Analyzing Stakeholder Influence and Collaboration Patterns

[Context and motivation] Ecosystems developed as Open Source Software (OSS) are considered to be highly innovative and reactive to new market trends due to their openness and wide-ranging contributor base. Participation in OSS often implies opening up of the software development process and exposure towards new stakeholders. [Question/Problem] Firms considering to engage in such an environment should carefully consider potential opportunities and challenges upfront. The openness may lead to higher innovation potential but also to frictional losses for engaged firms. Further, as an ecosystem progresses, power structures and influence on feature selection may fluctuate accordingly. [Principal ideas/results] We analyze the Apache Hadoop ecosystem in a quantitative longitudinal case study to investigate changing stakeholder influence and collaboration patterns. Further, we investigate how its innovation and time-to-market evolve at the same time. [Contribution] Findings show collaborations between and influence shifting among rivaling and non-competing firms. Network analysis proves valuable on how an awareness of past, present and emerging stakeholders, in regards to power structure and collaborations may be created. Furthermore, the ecosystem’s innovation and time-to-market show strong variations among the release history. Indications were also found that these characteristics are influenced by the way how stakeholders collaborate with each other