986 resultados para Fisher, Abby.


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"Preface and apology" on p. [3] contains information on Mrs. Fisher's life and names of benefactors in San Francisco and Oakland who assisted her in writing the book.

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The Wright-Fisher model is an Itô stochastic differential equation that was originally introduced to model genetic drift within finite populations and has recently been used as an approximation to ion channel dynamics within cardiac and neuronal cells. While analytic solutions to this equation remain within the interval [0,1], current numerical methods are unable to preserve such boundaries in the approximation. We present a new numerical method that guarantees approximations to a form of Wright-Fisher model, which includes mutation, remain within [0,1] for all time with probability one. Strong convergence of the method is proved and numerical experiments suggest that this new scheme converges with strong order 1/2. Extending this method to a multidimensional case, numerical tests suggest that the algorithm still converges strongly with order 1/2. Finally, numerical solutions obtained using this new method are compared to those obtained using the Euler-Maruyama method where the Wiener increment is resampled to ensure solutions remain within [0,1].

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Background: Standard methods for quantifying IncuCyte ZOOM™ assays involve measurements that quantify how rapidly the initially-vacant area becomes re-colonised with cells as a function of time. Unfortunately, these measurements give no insight into the details of the cellular-level mechanisms acting to close the initially-vacant area. We provide an alternative method enabling us to quantify the role of cell motility and cell proliferation separately. To achieve this we calibrate standard data available from IncuCyte ZOOM™ images to the solution of the Fisher-Kolmogorov model. Results: The Fisher-Kolmogorov model is a reaction-diffusion equation that has been used to describe collective cell spreading driven by cell migration, characterised by a cell diffusivity, D, and carrying capacity limited proliferation with proliferation rate, λ, and carrying capacity density, K. By analysing temporal changes in cell density in several subregions located well-behind the initial position of the leading edge we estimate λ and K. Given these estimates, we then apply automatic leading edge detection algorithms to the images produced by the IncuCyte ZOOM™ assay and match this data with a numerical solution of the Fisher-Kolmogorov equation to provide an estimate of D. We demonstrate this method by applying it to interpret a suite of IncuCyte ZOOM™ assays using PC-3 prostate cancer cells and obtain estimates of D, λ and K. Comparing estimates of D, λ and K for a control assay with estimates of D, λ and K for assays where epidermal growth factor (EGF) is applied in varying concentrations confirms that EGF enhances the rate of scratch closure and that this stimulation is driven by an increase in D and λ, whereas K is relatively unaffected by EGF. Conclusions: Our approach for estimating D, λ and K from an IncuCyte ZOOM™ assay provides more detail about cellular-level behaviour than standard methods for analysing these assays. In particular, our approach can be used to quantify the balance of cell migration and cell proliferation and, as we demonstrate, allow us to quantify how the addition of growth factors affects these processes individually.

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A systematic method is formulated to carry out theoretical analysis in a multilocus multiallele genetic system. As a special application, the Fundamental Theorem of Natural Selection is proved (in the continuous time model) for a multilocus multiallele system if all pairwise linkage disequilibria are zero.

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A fully discrete C-0 interior penalty finite element method is proposed and analyzed for the Extended Fisher-Kolmogorov (EFK) equation u(t) + gamma Delta(2)u - Delta u + u(3) - u = 0 with appropriate initial and boundary conditions, where gamma is a positive constant. We derive a regularity estimate for the solution u of the EFK equation that is explicit in gamma and as a consequence we derive a priori error estimates that are robust in gamma. (C) 2013 Elsevier B.V. All rights reserved.

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Fisher families had been investigated by the Department of Commerce and Industries in earlier economic surveys conducted in 1935, 1938 and 1939 (Das Gupta, 1937 a & b; 1944 a & b). These surveys were directed at the general economic conditions of the urban and rural sectors of the population and therefore did not provide much information in particular on the life of the fisherman or his environment. The Department of Fisheries in 1954 conducted a rapid enquiry into the living conditions of fishermen to obtain some data on their income, indebtedness and general social conditions, at the request of the Canadian Co-operative Consultant for incorporation in his report on the "Status and Possibilities of Co-operative Development of the Fisheries of Ceylon” (MacDonald, 1954). The present survey was undertaken to provide more definite socio-economic information on the fishermen of Ceylon, covering such aspects as income, expenditure, indebtedness and living conditions. The survey was started in June, 1958, but was interrupted by the unsettled conditions of the Island at the time, taking therefore a little over a year for completion. Some of the data collected was used as a basis for a report on the living conditions of fishermen, incorporated in the “Guide to the Fisheries of Ceylon", a hand book published by the Department of Fisheries (Anon. 1958).

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The objectives of the study was to provide information on the changes in the socio- economis status of the fisher communities.The study aimed at contributing to the following selected OVIs of the IFMP log frame:"10% increased in incomes from fish catches by fishing crews by EOP",20% women in BMUs reporting increased household incomefrom fishing by EOP","50% women and fishing crews in BMUs reporting greater say in fisheries decision making.

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A study was undertaken to find out the impact of ten days fishing ban in the major spawning grounds of hilsa during October to December. The study revealed a positive impact of fishing ban during spawning season on reproduction success of hilsa. Proportionate distribution of male and female hilsa also showed a significant level of distribution in and around the spawning grounds where the ratio was 35:65. Percent of oozing hilsa during fishing ban period in the spawning grounds was observed 1.61%. About 5% spent hilsa was observed in the fish landing centers and was compared with the data of Global Environment Facility (GEF) and Bangladesh Fisheries Research Institute (BFRI) studies and was found about 2.80-3.57 times higher than that of the findings of 2002 and 2003. Estimated egg production value showed about 46,800 Kg of eggs could have been produced that indicating a positive impact of 10 days fishing ban in spawning season. Abundance of higher percentages of gravid hilsa was found which were not available in the same quantity and condition in the non-fishing ban period. During the present investigation, fairly higher amount of spent hilsa and juveniles were also observed in the spawning grounds. Along with the jatka fry, spawn and fries of other fishes were also found in higher quantity than the previous years and thus it is assumed that fishing ban also might have positive impact on the successful breeding of other fishes. Overall, the fishing ban was found effective for successful breeding of hilsa.

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In Bangladesh, wetlands are managed through leasing system traditionally from time immemorial. Recently the Government accepted co-management approach for wetland fisheries management and this approach is being practiced in few wetlands for maximize revenue income. A study was carried out to evaluate trend and impact of co-management in Tanguar haor (a Ramsar site wetland) on fisheries resources and livelihood of resident people in the immediate vicinity of the wetland. In Tanguar haor, conflict between leaseholders and the local community was a common phenomenon in the past. Since 2003 the district administration of Sunamganj has been managing the vast wetland resources, however, local people participation was ignored in haor management system. Average monthly fish catch of fishermen increased by 17% after introduction of co-management system and 7 fish species reappeared after introduction of co-management. Average monthly volume of fish catch has increased from 70 kg to 87 kg. A well-defined management structure has been developed for integration of all people of Tanguar haor which would enable them to raise voice jointly and influence policy in their favour.

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Michael Rojas, a 24-year-old artisanal fisher from Caballo Island in Costa Rica, believes that youth can pursue fishing in an artisanally responsible and sustainable way.