The utility of a digital simulation language for ecological modeling

Dynamic modeling of ecological phenomena has been greatly facilitated by the recent development of continuous system simulator programs. This paper illustrates the application of one of these programs, S/360 Continuous System Modeling Program (S/360 CSMP), to four systems of graduated complexity. The first is a two species system, with one feeding on the other, using differential equations with constant coefficients. The second and third systems involve two competing plant species in which the coefficients of the differential equations are varying with time. The final example considers the management of a postulated buffalo herd in which the dynamics of the herd population and composition by sex and age is combined with various strategies to control its size and to optimize buffalo production

Mass Parameterizations and Predictions of Isotopic Observables

We discuss the accuracy of mass models for extrapolating to very asymmetric nuclei and the impact of such extrapolations on the predictions of isotopic observables in multifragmentation. We obtain improved mass predictions by incorporating measured masses and extrapolating to unmeasured masses with a mass formula that includes surface symmetry and Coulomb terms. We find that using accurate masses has a significant impact on the predicted isotopic observables.Comment: 12 pages, 4 figure

Measurement of Fluorescence Phenomena from Yttrium and Gadolinium Oxysulfide Phosphors using a 45-MeV Proton Beam

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Interventions for hand eczema

BackgroundHand eczema is an inflammation of the skin of the hands that tends to run a chronic, relapsing course. This common condition is often associated with itch, social stigma, and impairment in employment. Many different interventions of unknown effectiveness are used to treat hand eczema.ObjectivesTo assess the effects of topical and systemic interventions for hand eczema in adults and children.Search methodsWe searched the following up to April 2018: Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, AMED, LILACS, GREAT, and four trials registries. We checked the reference lists of included studies for further references to relevant trials.Selection criteriaWe included randomised controlled trials (RCTs) that compared interventions for hand eczema, regardless of hand eczema type and other affected sites, versus no treatment, placebo, vehicle, or active treatments.Data collection and analysisWe used standard methodological procedures expected by Cochrane. Primary outcomes were participant‐ and investigator‐rated good/excellent control of symptoms, and adverse events.Main resultsWe included 60 RCTs, conducted in secondary care (5469 participants with mild to severe chronic hand eczema). Most participants were over 18 years old. The duration of treatment was short, generally up to four months. Only 24 studies included a follow‐up period. Clinical heterogeneity in treatments and outcome measures was evident. Few studies performed head‐to‐head comparisons of different interventions. Risk of bias varied considerably, with only five studies at low risk in all domains. Twenty‐two studies were industry‐funded.Eighteen trials studied topical corticosteroids or calcineurin inhibitors; 10 studies, phototherapy; three studies, systemic immunosuppressives; and five studies, oral retinoids. Most studies compared an active intervention against no treatment, variants of the same medication, or placebo (or vehicle). Below, we present results from the main comparisons.Corticosteroid creams/ointments: when assessed 15 days after the start of treatment, clobetasol propionate 0.05% foam probably improves participant‐rated control of symptoms compared to vehicle (risk ratio (RR) 2.32, 95% confidence interval (CI) 1.38 to 3.91; number needed to treat for an additional beneficial outcome (NNTB) 3, 95% CI 2 to 8; 1 study, 125 participants); the effect of clobetasol compared to vehicle for investigator‐rated improvement is less clear (RR 1.43, 95% CI 0.86 to 2.40). More participants had at least one adverse event with clobetasol (11/62 versus 5/63; RR 2.24, 95% CI 0.82 to 6.06), including application site burning/pruritus. This evidence was rated as moderate certainty.When assessed 36 weeks after the start of treatment, mometasone furoate cream used thrice weekly may slightly improve investigator‐rated symptom control compared to twice weekly (RR 1.23, 95% CI 0.94 to 1.61; 1 study, 72 participants) after remission is reached. Participant‐rated symptoms were not measured. Some mild atrophy was reported in both groups (RR 1.76, 95% CI 0.45 to 6.83; 5/35 versus 3/37). This evidence was rated as low certainty.Irradiation with ultraviolet (UV) light: local combination ultraviolet light therapy (PUVA) may lead to improvement in investigator‐rated symptom control when compared to local narrow‐band UVB after 12 weeks of treatment (RR 0.50, 95% CI 0.22 to 1.16; 1 study, 60 participants). However, the 95% CI indicates that PUVA might make little or no difference. Participant‐rated symptoms were not measured. Adverse events (mainly erythema) were reported by 9/30 participants in the narrow‐band UVB group versus none in the PUVA group. This evidence was rated as moderate certainty.Topical calcineurin inhibitors: tacrolimus 0.1% over two weeks probably improves investigator‐rated symptom control measured after three weeks compared to vehicle (14/14 tacrolimus versus 0/14 vehicle; 1 study). Participant‐rated symptoms were not measured. Four of 14 people in the tacrolimus group versus zero in the vehicle group had well‐tolerated application site burning/itching.A within‐participant study in 16 participants compared 0.1% tacrolimus to 0.1% mometasone furoate but did not measure investigator‐ or participant‐rated symptoms. Both treatments were well tolerated when assessed at two weeks during four weeks of treatment.Evidence from these studies was rated as moderate certainty.Oral interventions: oral cyclosporin 3 mg/kg/d probably slightly improves investigator‐rated (RR 1.88, 95% CI 0.88 to 3.99; 1 study, 34 participants) or participant‐rated (RR 1.25, 95% CI 0.69 to 2.27) control of symptoms compared to topical betamethasone dipropionate 0.05% after six weeks of treatment. The risk of adverse events such as dizziness was similar between groups (up to 36 weeks; RR 1.22, 95% CI 0.80 to 1.86, n = 55; 15/27 betamethasone versus 19/28 cyclosporin). The evidence was rated as moderate certainty.Alitretinoin 10 mg improves investigator‐rated symptom control compared with placebo (RR 1.58, 95% CI 1.20 to 2.07; NNTB 11, 95% CI 6.3 to 26.5; 2 studies, n = 781) and alitretinoin 30 mg also improves this outcome compared with placebo (RR 2.75, 95% CI 2.20 to 3.43; NNTB 4, 95% CI 3 to 5; 2 studies, n = 1210). Similar results were found for participant‐rated symptom control: alitretinoin 10 mg RR 1.73 (95% CI 1.25 to 2.40) and 30 mg RR 2.75 (95% CI 2.18 to 3.48). Evidence was rated as high certainty. The number of adverse events (including headache) probably did not differ between alitretinoin 10 mg and placebo (RR 1.01, 95% CI 0.66 to 1.55; 1 study, n = 158; moderate‐certainty evidence), but the risk of headache increased with alitretinoin 30 mg (RR 3.43, 95% CI 2.45 to 4.81; 2 studies, n = 1210; high‐certainty evidence). Outcomes were assessed between 48 and 72 weeks.Authors' conclusionsMost findings were from single studies with low precision, so they should be interpreted with caution. Topical corticosteroids and UV phototherapy were two of the major standard treatments, but evidence is insufficient to support one specific treatment over another. The effect of topical calcineurin inhibitors is not certain. Alitretinoin is more effective than placebo in controlling symptoms, but advantages over other treatments need evaluating.Well‐designed and well‐reported, long‐term (more than three months), head‐to‐head studies comparing different treatments are needed. Consensus is required regarding the definition of hand eczema and its subtypes, and a standard severity scale should be established.The main limitation was heterogeneity between studies. Small sample size impacted our ability to detect differences between treatments

Regularization-independent study of renormalized non-perturbative quenched QED

A recently proposed regularization-independent method is used for the first time to solve the renormalized fermion Schwinger-Dyson equation numerically in quenched QED$_4$. The Curtis-Pennington vertex is used to illustrate the technique and to facilitate comparison with previous calculations which used the alternative regularization schemes of modified ultraviolet cut-off and dimensional regularization. Our new results are in excellent numerical agreement with these, and so we can now conclude with confidence that there is no residual regularization dependence in these results. Moreover, from a computational point of view the regularization independent method has enormous advantages, since all integrals are absolutely convergent by construction, and so do not mix small and arbitrarily large momentum scales. We analytically predict power law behaviour in the asymptotic region, which is confirmed numerically with high precision. The successful demonstration of this efficient new technique opens the way for studies of unquenched QED to be undertaken in the near future.Comment: 20 pages,5 figure

Pulse dispersion in glass fibres

Measurements indicate that pulses incident normally on the end of a cladded multimode fibre are broadened by less than 0.1 ns over a length of 20 m. The measured dispersions in lengths of 20 m and 35 m do not exceed 5 ps/m. However, with an angle of incidence of 17°, or with a defocused input beam, the pulses are broadened by 0.6 ns

Relativistic many-body calculations of electric-dipole matrix elements, lifetimes and polarizabilities in rubidium

Electric-dipole matrix elements for ns-n'p, nd-n'p, and 6d-4f transitions in Rb are calculated using a relativistic all-order method. A third-order calculation is also carried out for these matrix elements to evaluate the importance of the high-order many-body perturbation theory contributions. The all-order matrix elements are used to evaluate lifetimes of ns and np levels with n=6, 7, 8 and nd levels with n=4, 5, 6 for comparison with experiment and to provide benchmark values for these lifetimes. The dynamic polarizabilities are calculated for ns states of rubidium. The resulting lifetime and polarizability values are compared with available theory and experiment.Comment: 8 pages, 2 figure

Uptake of gases in bundles of carbon nanotubes

Model calculations are presented which predict whether or not an arbitrary gas experiences significant absorption within carbon nanotubes and/or bundles of nanotubes. The potentials used in these calculations assume a conventional form, based on a sum of two-body interactions with individual carbon atoms; the latter employ energy and distance parameters which are derived from empirical combining rules. The results confirm intuitive expectation that small atoms and molecules are absorbed within both the interstitial channels and the tubes, while large atoms and molecules are absorbed almost exclusively within the tubes.Comment: 9 pages, 12 figures, submitted to PRB Newer version (8MAR2K). There was an error in the old one (23JAN2K). Please download thi

Tracking the reflexivity of the (dis)engaged citizen: some methodological reflections

The relationship between governments and citizens in many contemporary democracies is haunted by uncertainty and sociologists face the task of listening effectively to citizens’ own reflections on this uncertain relationship. This article reflects on the qualitative methodology of a recently completed UK project which used a combination of diary and multiple interviews/ focus groups to track over a fieldwork period of up to a year citizens’ reflections on their relationship to a public world and the contribution to this of their media consumption. In particular, the article considers how the project’s multiple methods enabled multiple angles on the inevitable artificiality and performative dimension of the diary process, resulting in rich data on people’s complex reflections on the uncertain position of the contemporary citizen