14 research outputs found
Modeling postbreakup landscape development and denudational history across the southeast African (Drakensberg Escarpment) margin
No full textWe employ a numerical surface processes model to study the controls on postbreakup landscape development and denudational history of the southeast African margin. Apatite fission track data, presented in the companion paper, suggest that the Drakensberg Escarpment formed by rapid postbreakup river incision seaward of a preexisting drainage divide, located close to its present position, and subsequently retreated at rates of only ∼100 m m.y.−1. Numerical modeling results support such a scenario and show that the prebreakup topography of the margin has exerted a fundamental control on subsequent margin evolution. The rheology of the lithosphere, lithological variations in the eroding upper crust, and inland base level falls provided secondary controls. A relatively low flexural rigidity of the lithosphere (Te ≈ 10 km) is required to explain the observed pattern of denudation as well as the observed geological structure of the southeast African margin. Lithological variations have contributed to the formation of flat-topped ridges buttressing the main escarpment, as well as major fluvial knickpoints. Both these features have previously been interpreted as supporting significant Cenozoic uplift of the margin. An inland base level fall, possibly related to back-cutting of the Orange River drainage system and occurring 40–50 m.y. after breakup, explains the observed denudation inland of the escarpment as well as the development of inland drainage parallel to the escarpment. Our model results suggest that in contrast to widely accepted inferences from classical geomorphic studies, the southeast African margin has remained tectonically stable since breakup and escarpment retreat has been minimal (<25 km)
Early health economic analysis of virtual reality therapy for pain management after surgery
No full textINTRODUCTION: Virtual reality (VR) therapy is increasingly used to mitigate pain and anxiety in inpatient settings, with varying effectiveness in postoperative settings. The costs of VR therapy also differ among suppliers. This health-economic analysis aims to inform policy- and decision-makers on the potential impact of VR therapy from a societal perspective based on pain management at discharge and the development of chronic postsurgical pain (CPSP). METHODS: A Markov model was developed to simulate 1-year postoperative costs and effects. Using a threshold and headroom analysis, the Incremental Cost-effectiveness Ratio (ICER) was calculated for various VR effectiveness estimates and costs when VR therapy demonstrated cost-effectiveness or cost-savings for postoperative pain management. VR effectiveness was based on opioid use at discharge, affecting the Markov model's initial distribution and CPSP development. The ICER was calculated from quality-adjusted life-years (QALYs) and costs associated with CPSP. A univariate sensitivity analysis was used to assess parameter uncertainty by varying each parameter by ±20% from the base-case value. RESULTS: VR therapy needs to reduce opioid use at discharge by at least 2.8% to be cost-effective at a willingness-to-pay threshold of €20 000 per QALY and VR costs of €47.48 per patient. To be cost-saving, a reduction of at least 6.5% is needed. The sensitivity analysis indicated that the transition probability from "pain with opioid" to "pain free" in month 2 had the most impact on the ICER. Other significant variables included VR effectiveness and costs, each influencing the ICER by over €5000. CONCLUSION: The needed 2.8% reduction in opioid use at discharge seems plausible based on literature. However, knowledge gaps regarding the effectiveness of VR, the incidence of chronic postoperative pain, and societal costs of chronic pain need to be addressed, to better understand VR therapy's role in optimizing postoperative pain management.</p
Nonlinear modeling of FES-supported standing-up in paraplegia for selection of feedback sensors
No full textThis paper presents analysis of the standing-up manoeuvre in paraplegia considering the body supportive forces as a potential feedback source in functional electrical stimulation (FES)-assisted standing-up. The analysis investigates the significance of arm, feet, and seat reaction signals to the human body center-of-mass (COM) trajectory reconstruction. The standing-up behavior of eight paraplegic subjects was analyzed, measuring the motion kinematics and reaction forces to provide the data for modeling. Two nonlinear empirical modeling methods are implemented-Gaussian process (GP) priors and multilayer perceptron artificial neural networks (ANN)-and their performance in vertical and horizontal COM component reconstruction is compared. As the input, ten sensory configurations that incorporated different number of sensors were evaluated trading off the modeling performance for variables chosen and ease-of-use in everyday application. For the purpose of evaluation, the root-mean-square difference was calculated between the model output and the kinematics-based COM trajectory. Results show that the force feedback in COM assessment in FES assisted standing-up is comparable alternative to the kinematics measurement systems. It was demonstrated that the GP provided better modeling performance, at higher computational cost. Moreover, on the basis of averaged results, the use of a sensory system incorporating a six-dimensional handle force sensor and an instrumented foot insole is recommended. The configuration is practical for realization and with the GP model achieves an average accuracy of COM estimation 16 /spl plusmn/ 1.8 mm in horizontal and 39 /spl plusmn/ 3.7 mm in vertical direction. Some other configurations analyzed in the study exhibit better modeling accuracy, but are less practical for everyday usage
<sup>18</sup>F–Sodium Fluoride Uptake in Abdominal Aortic Aneurysms: The SoFIA3 Study
No full textBackground: Fluorine-18–sodium fluoride (18F-NaF) uptake is a marker of active vascular calcification associated with high-risk atherosclerotic plaque.Objectives: In patients with abdominal aortic aneurysm (AAA), the authors assessed whether 18F-NaF positron emission tomography (PET) and computed tomography (CT) predicts AAA growth and clinical outcomes.Methods: In prospective case-control (n = 20 per group) and longitudinal cohort (n = 72) studies, patients with AAA (aortic diameter >40 mm) and control subjects (aortic diameter <30 mm) underwent abdominal ultrasound, 18F-NaF PET-CT, CT angiography, and calcium scoring. Clinical endpoints were aneurysm expansion and the composite of AAA repair or rupture.Results: Fluorine-18-NaF uptake was increased in AAA compared with nonaneurysmal regions within the same aorta (p = 0.004) and aortas of control subjects (p = 0.023). Histology and micro-PET-CT demonstrated that 18F-NaF uptake localized to areas of aneurysm disease and active calcification. In 72 patients within the longitudinal cohort study (mean age 73 ± 7 years, 85% men, baseline aneurysm diameter 48.8 ± 7.7 mm), there were 19 aneurysm repairs (26.4%) and 3 ruptures (4.2%) after 510 ± 196 days. Aneurysms in the highest tertile of 18F-NaF uptake expanded 2.5× more rapidly than those in the lowest tertile (3.10 [interquartile range (IQR): 2.34 to 5.92 mm/year] vs. 1.24 [IQR: 0.52 to 2.92 mm/year]; p = 0.008) and were nearly 3× as likely to experience AAA repair or rupture (15.3% vs. 5.6%; log-rank p = 0.043).Conclusions: Fluorine-18-NaF PET-CT is a novel and promising approach to the identification of disease activity in patients with AAA and is an additive predictor of aneurysm growth and future clinical events. (Sodium Fluoride Imaging of Abdominal Aortic Aneurysms [SoFIA3]; NCT02229006; Magnetic Resonance Imaging [MRI] for Abdominal Aortic Aneurysms to Predict Rupture or Surgery: The MA3RS Trial; ISRCTN76413758)<br/
Geographies of hepatitis C : exploring the extent to which geographic accessibility to healthcare influences outcomes amongst individuals infected with Hepatitis C in NHS Tayside, Scotland
No full textMillions of people are infected with the Hepatitis C Virus (HCV) worldwide. In the UK, many
individuals continue to live with undiagnosed HCV infection and are increasingly at risk of
developing life-threatening cirrhosis and liver cancer. Of those that are diagnosed, only some
are referred to an HCV specialist centre where vital treatment could cure their infection. Of
those that are referred, only a proportion have actually attended and stayed in follow-up with a
specialist centre. Geographic access to healthcare may be an important factor in these trends,
but has so far received little attention in the context of HCV.
This thesis examines the influence of geographic access to primary and specialist healthcare on
HCV detection, trends of referral, chances of specialist centre utilisation and the odds of staying
in follow-up. It also explores association between geographic access and the type of location in
which diagnoses were made with the risk of mortality from liver-related causes. HCV detection
was lower amongst those with poorer geographic access to primary healthcare, but further
analyses suggest this trend is due to selection, not causation. Individuals with the furthest to
travel were less likely to be referred to an HCV specialist centre, compared to those who lived
closer. Travel-time was not a significant predictor of utilisation of HCV specialist centres, but
with patients in more remote areas less likely to be referred, it is probable that the utilisation
result is biased due to selection. Liver-related mortality was higher for patients diagnosed in
hospitals, but the risk of death was not associated with a lack of geographic access to healthcare
Screening older people for impaired vision
No full textA systematic review of trials about screening
older
people
for
visual
impairment found no evidence that screening
improved
vision.
We
undertook
a new trial nested within a larger cluster randomised
trial
of
multidimensional
screening for people aged 75 years and over.
106
general
practices
were
randomised to: targeted screening in which only a small
proportion
of
participants with a range of health problems
were offered
visual
acuity
screening, and universal screening
in
which all
participants
were offered
visual acuity screening. People identified with
impaired
vision
were
referred
to the eye services. Around 220 participants were randomly
sampled
from
ten practices in each group and visual outcomes measured
at
three to five
years.
The response rate to the baseline assessments was
76.1
Over
one
third
of
eligible participants died before having an outcome assessment.
Of those
alive, 67.8% in the targeted screening group
and
57.9% in the
universal
group completed an outcome assessment.
At
outcome
37.0%
(307/829) in
the universal group had visual acuity of
less than
6/18 in
either eye compared
with 34.7% (339/978) in the targeted group
(odds
ratio
1.11,95%
confidence
interval 0.76 to 1.62, P=0.58). The 25 item
National Eye Institute
Visual
Function Questionnaire composite score
was
86.03 in the
universal group
and 85.62 in the targeted group (difference 0.41,95%
confidence
interval
-
1.68 to 2.50, P=0.69). Although visual
impairment
was
common,
few
people
benefited from subsequent intervention. Possible
explanations
for the lack
of
effect include: chance; under-detection of uncorrected
refractive
error
and
that only around half the recommendations
for
referral
to
an
ophthalmologist
resulted in referral
Epidemiology of lameness in dairy cows
No full textFour visits were made to 50 dairy farms in England and Wales between February 2003 and February 2004 and a further three visits to 42 of these farms between February 2005 and February 2006. At each visit the locomotion of all cows was scored (15,597 cows, 34,643 measures). Multivariable regression analyses were preformed to identify risk factors associated with increased lameness (poor locomotion). Factors associated with mean herd poor locomotion were dry cows kept in straw yards compared with cubicle houses, pregnant heifers kept with milking cows compared with dry cows in winter, passage way widths 15cm, routine trimming of claws ofall cows by a claw trimmer or by- the farmer compared with no routine claw trimming, feeding maize silage to milking cows compared with other forage types, and the use of automatic scrapers compared with tractor scrapers in the cubicle house. Farmers recorded the lesions they observed while treating lame cows. Sole ulcer, white line disease and digital dermatitis were the three most frequently recorded lesions. The occurrence of sole ulcer, white line disease or digital dermatitis compared with having no lesion was used as the outcome variable in three multilevel binomial logistic regression models with month from calving nested within cow nested within farm. Risk factors associated with increased risk of sole ulcer were being housed on sparse bedding for four months or more, having grooved concrete floors on ~e farm, large herd sizes and parity numbers of four and above. Risk factors associated with increased white line disease were grooved concrete floors increasing parity number. Risk factors associated with increased digital dermatitis were grooved concrete floors and large herd sizes. A large clinical trial was used to assess the effect of intervening on known risk factors associated with lameness. Farmers in the treatment group received farm specific recommendations grouped under five targets areas which reflected the hypothesised aetiologies of sole ulcer, white line disease and digital dermatitis. There were small reductions in locomotion score and sole ulcer rate on treatment farms compared with control. These suggested that the hypotheses that reduced standing time and encouraged increased lying time through improved cow comfort may reduce sole ulcer were, at least in part, correct. There was no clear effect of treatment on the rate white line disease and digital dermatitis. It is likely that more than one of the following factors explain the lack of significant results from these initial investigations; poor recognition oflameness by farmers, insufficient uptake of recommendations, predisposition to lameness from previous lameness event and insufficiently specific lesion definitions
Wissensstandsanalyse zu Qualität, Verbraucherschutz und Verarbeitung ökologischer Lebensmittel
No full textZielsetzung des Projektes war es, den aktuellen Stand des Wissens zur Qualität und Verarbeitung ökologischer Lebensmittel sowie zum Verbraucherschutz aufzuzeigen und zu bewerten.
Das Projektteam setzte sich aus Wissenschaftlern des Forschungsinstituts für biologischen Landbau (Deutschland und Schweiz), des Büros für Lebensmittelkunde, des Forschungsrings für Biologisch-Dynamische Wirtschaftsweise e.V. sowie des Fachgebiets Ökologische Lebensmittelqualität und Ernährungskultur der Universität Kassel zusammen.
In dem zeitlich sehr begrenzten Projekt fokussierte die Arbeitsgruppe die Betrachtung auf folgende Themenkomplexe und Produktgruppen:
Bereich Qualität
- Ernährung
- Sensorik
- Ökospezifische Qualitäten
- Authentizität und Rückverfolgbarkeit
Bereich Verarbeitung
- Rohwaren/Lagerung und Technologien für die Produktgruppen:
-- Getreide
-- Milch
-- Fleisch
-- Obst und Gemüse und Erzeugnisse aus diesen
- Nachhaltigkeit im Unternehmen und entlang der Prozesskette
- Verpackung
Vorhandenes Wissen, aktuelle Fragestellungen und Entwicklungsrichtungen wurden nach thematisch angepassten Vorgehensweisen identifiziert und anhand internationaler Literatur und Experteninterviews diskutiert.
Zu allen Themenkomplexen wurden kurze und allgemeinverständliche Reports erstellt, die einen schnellen und fundierten Überblick zum aktuellen Stand des Wissens und zu eventuellen Wissenslücken geben. Der Abschlussreport wurde in deutscher und englischer Sprache veröffentlicht.
Insgesamt wurde festgestellt, dass in den betrachteten Themenkomplexen erheblicher Bedarf an Forschung und Entwicklung sowie an Wissenstransfer besteht. Neben einer Reihe von Detailfragen sind grundlegende Themen, wie beispielsweise das Anforderungsprofil an eine „ökologische Verarbeitung“, nicht hinreichend erforscht und geklärt. Diese Arbeiten sind jedoch Voraussetzung für die Bearbeitung von Detailthemen, da hier Aufgabenstellungen, Schwerpunktsetzungen und Methoden definiert werden
Turn down the heat
No full textThis report provides a snapshot of recent scientific literature and new analyses of likely impacts and risks that would be associated with a 4° Celsius warming within this century. It is a rigorous attempt to outline a range of risks, focusing on developing countries and especially the poor. A 4°C world would be one of unprecedented heat waves, severe drought, and major floods in many regions, with serious impacts on ecosystems and associated services. But with action, a 4°C world can be avoided and we can likely hold warming below 2°C.
Without further commitments and action to reduce greenhouse gas emissions, the world is likely to warm by more than 3°C above the preindustrial climate. Even with the current mitigation commitments and pledges fully implemented, there is roughly a 20 percent likelihood of exceeding 4°C by 2100.
If they are not met, a warming of 4°C could occur as early as the 2060s. Such a warming level and associated sea-level rise of 0.5 to 1 meter, or more, by 2100 would not be the end point: a further warming to levels over 6°C, with several meters of sea-level rise, would likely occur over the following centuries
