1,624 research outputs found

    FISHRENT; Bio-economic simulation and optimisation model

    Get PDF
    Key findings: The FISHRENT model is a major step forward in bio-economic model-ling, combining features that have not been fully integrated in earlier models: 1- Incorporation of any number of species (or stock) and/or fleets 2- Integration of simulation and optimisation over a period of 25 years 3- Integration of effort and TAC-driven management policies 4- Three independent relations for stock growth, production and investments. The feedbacks within the model allow for a dynamic simulation. The main application of the model is scenario analysis of policy options. Complementary findings: The model formulates a complete set of mathematical relations, but it also con-tains a number of important assumptions, which remain to be tested empirically. Therefore the model presents a challenging agenda for empirical research, which should lead to further qualitative and quantitative improvements of the in-dividual mathematical equations and parameter values. Method: This model was developed during the EU-funded project 'Remuneration of spawning stock biomass'. Its aim was to generate consistent sets of scenarios for an assessment of potential resource rents in different EU fisheries. The model comprises six modules, each focussing on a different aspect of the functioning of the fisheries system: biology (stocks), economy (costs, earnings and profits), policy (TACs, effort and access fees), behaviour (investments), prices (fish and fuel) and an interface linking the modules together. Input, calculation and output are clearly separated. The model produces a standard set of graphics, which provide a quick insight into the results of any model run. All output of the model runs can be exported to database software for further analysis. The model has been built in Excel, which makes it accessible for most us-ers. It has been used in new applications and even translated to other software. The model is continually further developed

    The efficacy of intravitreal antivascular endothelial growth factor as primary treatment of retinopathy of prematurity: Experience from a tertiary hospital

    Get PDF
    Background. Retinopathy of prematurity (ROP) is a vasoproliferative disease affecting premature babies and a major cause of blindness in childhood. Appropriate screening and treatment can prevent blindness.Objective. To report on the efficacy of using antivascular endothelial growth factor (bevacizumab) as first-line therapy in ROP.Methods. This was a retrospective analysis of patients with ROP treated at St John Eye Hospital, Johannesburg, South Africa, over a 3-year period. Outcome measures were the clinical response to intravitreal bevacizumab (IVB) as well as the economic impact of IVB therapy.Results. Twenty-three patients were treated for active ROP or type 1 disease, in 44 eyes. Two patients required treatment in one eye only. The mean birth weight of these patients was 1 074 g (range 810 - 1 480). Response to treatment outcome was available for 22 patients (43 eyes). The mean follow-up period was 9 months (range 1 - 18). Forty-one eyes (95.3%) showed complete regression or non-progression of the disease. Two eyes (one eye each in two patients) progressed to advanced disease. There were no short-term adverse events. A cost-effective model showed that IVB treatment was much more economical than laser therapy.Conclusion. IVB is a safe and effective first-line treatment for ROP and should be considered in resource-limited centres

    Stochastic Resonance: influence of a fκf^{-\kappa} noise spectrum

    Get PDF
    Here, in order to study \textit{stochastic resonance} (SR) in a double-well potential when the noise source has a spectral density of the form fκf^{-\kappa} with varying κ\kappa, we have extended a procedure, introduced by Kaulakys et al (Phys. Rev. E \textbf{70}, 020101 (2004)). In order to have an analytical understanding of the results, we have obtained an effective Markovian approximation, that allows us to make a systematic study of the effect of such kind of noises on the SR phenomenon. The comparison of numerical and analytical results shows an excellent qualitative agreement indicating that the effective Markovian approximation is able to correctly describe the general trends.Comment: 11 pages, 6 figures, submitted to Euro.Phys.J.

    The efficacy of intravitreal antivascular endothelial growth factor as primary treatment of retinopathy of prematurity: Experience from a tertiary hospital

    Get PDF
    Background. Retinopathy of prematurity (ROP) is a vasoproliferative disease affecting premature babies and a major cause of blindness in childhood. Appropriate screening and treatment can prevent blindness.Objective. To report on the efficacy of using antivascular endothelial growth factor (bevacizumab) as first-line therapy in ROP.Methods. This was a retrospective analysis of patients with ROP treated at St John Eye Hospital, Johannesburg, South Africa, over a 3-year period. Outcome measures were the clinical response to intravitreal bevacizumab (IVB) as well as the economic impact of IVB therapy.Results. Twenty-three patients were treated for active ROP or type 1 disease, in 44 eyes. Two patients required treatment in one eye only. The mean birth weight of these patients was 1 074 g (range 810 - 1 480). Response to treatment outcome was available for 22 patients (43 eyes). The mean follow-up period was 9 months (range 1 - 18). Forty-one eyes (95.3%) showed complete regression or non-progression of the disease. Two eyes (one eye each in two patients) progressed to advanced disease. There were no short-term adverse events. A cost-effective model showed that IVB treatment was much more economical than laser therapy.Conclusion. IVB is a safe and effective first-line treatment for ROP and should be considered in resource-limited centres

    Creatinine, diet, micronutrients, and arsenic methylation in West Bengal, India.

    Get PDF
    BackgroundIngested inorganic arsenic (InAs) is methylated to monomethylated (MMA) and dimethylated metabolites (DMA). Methylation may have an important role in arsenic toxicity, because the monomethylated trivalent metabolite [MMA(III)] is highly toxic.ObjectivesWe assessed the relationship of creatinine and nutrition--using dietary intake and blood concentrations of micronutrients--with arsenic metabolism, as reflected in the proportions of InAS, MMA, and DMA in urine, in the first study that incorporated both dietary and micronutrient data.MethodsWe studied methylation patterns and nutritional factors in 405 persons who were selected from a cross-sectional survey of 7,638 people in an arsenic-exposed population in West Bengal, India. We assessed associations of urine creatinine and nutritional factors (19 dietary intake variables and 16 blood micronutrients) with arsenic metabolites in urine.ResultsUrinary creatinine had the strongest relationship with overall arsenic methylation to DMA. Those with the highest urinary creatinine concentrations had 7.2% more arsenic as DMA compared with those with low creatinine (p < 0.001). Animal fat intake had the strongest relationship with MMA% (highest tertile animal fat intake had 2.3% more arsenic as MMA, p < 0.001). Low serum selenium and low folate were also associated with increased MMA%.ConclusionsUrine creatinine concentration was the strongest biological marker of arsenic methylation efficiency, and therefore should not be used to adjust for urine concentration in arsenic studies. The new finding that animal fat intake has a positive relationship with MMA% warrants further assessment in other studies. Increased MMA% was also associated, to a lesser extent, with low serum selenium and folate

    Solving Medium-Density Subset Sum Problems in Expected Polynomial Time: An Enumeration Approach

    Full text link
    The subset sum problem (SSP) can be briefly stated as: given a target integer EE and a set AA containing nn positive integer aja_j, find a subset of AA summing to EE. The \textit{density} dd of an SSP instance is defined by the ratio of nn to mm, where mm is the logarithm of the largest integer within AA. Based on the structural and statistical properties of subset sums, we present an improved enumeration scheme for SSP, and implement it as a complete and exact algorithm (EnumPlus). The algorithm always equivalently reduces an instance to be low-density, and then solve it by enumeration. Through this approach, we show the possibility to design a sole algorithm that can efficiently solve arbitrary density instance in a uniform way. Furthermore, our algorithm has considerable performance advantage over previous algorithms. Firstly, it extends the density scope, in which SSP can be solved in expected polynomial time. Specifically, It solves SSP in expected O(nlogn)O(n\log{n}) time when density dcn/lognd \geq c\cdot \sqrt{n}/\log{n}, while the previously best density scope is dcn/(logn)2d \geq c\cdot n/(\log{n})^{2}. In addition, the overall expected time and space requirement in the average case are proven to be O(n5logn)O(n^5\log n) and O(n5)O(n^5) respectively. Secondly, in the worst case, it slightly improves the previously best time complexity of exact algorithms for SSP. Specifically, the worst-case time complexity of our algorithm is proved to be O((n6)2n/2+n)O((n-6)2^{n/2}+n), while the previously best result is O(n2n/2)O(n2^{n/2}).Comment: 11 pages, 1 figur

    Gingival Pigmentation Pattern in Correlation to Skin Color in a Group of Kurdish People in Sulaimani City

    Get PDF
    Background: Melanin pigmentation of the gingiva appears in all ethnicities. Excessive pigmentation is an esthetic concern that has increased awareness about depigmentation procedures. This epidemiological study aims to find the correlation between skin color and gingival pigmentation in Sulaimani Governorate, Kurdistan/Iraq. Subjects and Methods: A total of 820 apparently healthy and non-smokers, including 338 males and 482 females with healthy gingiva, aged between (18-40 years old) were enrolled in this study. Clinical examination on the participants’ gingivae was performed to assess color, and the distribution of pigmentations. Afterward the of participants skin color were visually examined and divided into six groups according to the Fitzpatrick scale. Results: Skin color of (53%) of our participants was medium to light brown. Most of the pigmentations were observed in the attached gingiva and interdental papilla (26.83%) and least being in the marginal gingiva and interdental papilla (9.27%). A statistically significant correlation was found between the participants’ skin color, and the intensity of their gingival pigmentations   Conclusion: Darker-skinned subjects haveeavieringival pigmentation compared toair-skinned people in Sulaimani Governorate, Kurdistan/ Iraq. The intensity of gingival pigmentation increases with age with the highest rate of gingival pigmentation was in the upper and lower second premolar to premolar area

    Emission Characteristics of the Projectile Fragments at Relativistic Energy

    Full text link
    A projectile (84^Kr_36) having kinetic energy around 1 A GeV was used to expose NIKFI BR-2 emulsion target. A total of 700 inelastic events are used in the present studies on projectile fragments. The emission angle of the projectile fragments are strongly affected by charge of the other projectile fragments emitted at same time with different emission angle is observed. The angular distribution studies show symmetrical nature for lighter charge projectile fragments. The symmetrical nature decreased with the charge of projectile fragments. At ~4o of emission angle for double charge projectile fragments, the momentum transfer during interaction is similar for various target species of emulsion were observed. We also observed a small but significant amplitude peaks on both side of the big peak for almost all light charge projectile fragments having different delta angle values. It reflects that there are few percent of projectile fragments that are coming from the decay of heavy projectile fragments or any other process.Comment: 32 pages, 17 Figure
    corecore