Journal of the National Cancer Institute, Dec 1, 2016
Diffuse large B cell lymphoma (DLBCL) comprises multiple molecular and biological subtypes, resul... more Diffuse large B cell lymphoma (DLBCL) comprises multiple molecular and biological subtypes, resulting in a broad range of clinical outcomes. With standard chemoimmunotherapy, there remains an unacceptably high treatment failure rate in certain DLBCL subsets: activated B cell (ABC) DLBCL, double-hit lymphoma defined by the dual translocation of MYC and BCL2, dual protein-expressing lymphomas defined by the overexpression of MYC and BCL2, and older patients and those with central nervous system involvement. The main research challenges for DLBCL are to accurately identify molecular subsets and to determine if specific chemotherapy platforms and targeted agents offer differential benefit. The ultimate goal should be to maximize initial cure rates to improve long-term survival while minimizing toxicity. In particular, a frontline trial should focus on biologically defined risk groups not likely to be cured with cyclophosphamide, doxorubicin, vincristine, and prednisone plus rituximab (R...
Fisheries management operates in an environment characterized by multiple risks. These risks are ... more Fisheries management operates in an environment characterized by multiple risks. These risks are often complementary and can be traded off against each other. An important goal for managers is to develop strategies to minimize the overall risk exposure at minimal cost. We show a simple model that quantifies a range of risks faced by fisheries management agencies in terms of long-term expected budgetary expenditure. The model includes not only the cost a management agency would be expected to incur from overfishing a stock, or from being seen to overfish it, but also the social cost incurred from not achieving its objectives, such as the opportunity cost of foregoing catches and economic returns. These costs can be controlled by adjusting the biomass level targeted by management, or increasing expenditures for data collection to improve the precision of biomass estimates. The overall risk, expressed as the long-term total expected cost to a management agency, depends strongly on the fisheries management objectives, and the emphasis on conservation or economic motives. In general, management under a conservation-oriented objective would reduce risk either by increasing target biomass levels or by expenditure on monitoring and assessment, while a catch-focused objective would seek to lower management costs by reducing expenditure on data collection and assessment. Increased natural stock variability affects the risk of overfishing, and long-term expected costs as the ability to make a meaningful estimate of biomass declines. Management of catch-focused fisheries would reduce the biomass target as stock variability increases, because the benefit of catches are seen to outweigh the cost, or risk of being overfished. The model provides the basis for more extensive risk analyses, and serves as a simple lesson that the consequences of reducing the short-term costs associated with managing a fishery can come with a concomitant increase in overall risk. Keywords: false-negative estimation error, false-positive estimation error, fisheries management cost, risk – cost – catch trade-off, risk equivalency.
Balancing bio-economic risks and high profit expectations is often a major concern in fisheries m... more Balancing bio-economic risks and high profit expectations is often a major concern in fisheries management. We examine this trade-off in the context of the Australian Northern Prawn Fishery (NPF). The fishery derives its revenue from different prawn species with different dynamics and recruitment processes. A multi-species bio-economic and stochastic model is used to examine the trade-offs between mean profitability of the fishery and its variance, under a range of economic scenarios, fishing capacities and distributions of fishing effort across the various sub-fisheries that comprise the NPF. Simulation results show that the current fishing strategy diversifying catch across sub-components of the fishery entails a compromise between expected performance and risk. Furthermore, given the current economic conditions, increases in fleet size would improve the expected economic performance of the fishery, but at the cost of increased variability of this performance.
We present a modelling approach to rapidly assess the effect of management decisions on ecologica... more We present a modelling approach to rapidly assess the effect of management decisions on ecological problems and demonstrate its use in fishery management. Each stage of the approach is controlled by a Graphical User Interface which allows a team of non-expert modellers to compare the outcomes of multiple model simulations and to decide what further simulation is needed.A distinguishing feature of the method is that it allows the goal of the management strategies to arise as a result of the interaction between the user and the model, rather than being defined a priori, as well as to change during the process in response to the information and the insight such modelling may provide. We envisage that a management team, rather than a single user, may also employ the method as an avenue for communication, in order to discuss the potentially conflicting aspects of different model outcomes along the path to finding workable compromises. We discuss an application of the approach to the sustainable management of a recreational fishery in a marine park in Western Australia.
This paper deals with the sustainable management of a renewable resource based on individual and ... more This paper deals with the sustainable management of a renewable resource based on individual and transferable quotas (ITQs) when agents differ in terms of harvesting costs or catch capability. In a dynamic bio-economic model, we determine the feasibility conditions under which a fishery manager can achieve sustainability objectives which simultaneously account for stock conservation, economic efficiency and maintenance of fishing activity for the agents along time. We show how the viability of quota management strategies based on ITQ depends on the degree of heterogeneity of users in the fishery, the current status and the dynamics of the stock together with the selection of TAC schedules. In particular for a given stock, we compute the maximin effort for a given set of agents and we derive the maximal number of active agents for a given guaranteed effort. An application to the nephrops fishery in the Bay of Biscay illustrates the results.
Abstract Spatial management measures in the form of no-take areas used in fisheries management c... more Abstract Spatial management measures in the form of no-take areas used in fisheries management can provide a buffer against catastrophic events. Dynamic area closures, like rotational closures, have also been used as a management tool particularly for sessile organisms. In this study, bioeconomic models are developed to investigate dynamic closure strategies for use as a management tool in the harvest of a metapopulation consisting of two local sub-populations. The models provide an optimal strategy that maximises the sum of discounted net returns with a fixed harvest level [i.e. total allowable catch (TAC)] by opening and closing the sub-populations of a metapopulation, subject to random negative catastrophic effects. Results showed the optimal policy for opening and closing a single exploited population depends on the degree and pattern of migration between it and other sub-populations. When the harvest or TAC can be applied to either sub-population, the optimal closure strategy depends on the abundance of both populations, crucially, even if they are biologically independent. The results provide insights into the management of stochastically fluctuating populations including more mobile species that are frequently not subject to no-take controls.
1 Ecological patterns in space and time have been well documented using interval variables such a... more 1 Ecological patterns in space and time have been well documented using interval variables such as plant density. In this paper, we use join Page: 1Is the text OK: join count statistics to examine spatio-temporal patterns in a binary variable, plant establishment.2 Establishment along a belt transect is represented as a grid or lattice in which each cell denotes a particular quadrat in a particular year. A cell is ‘black’ if a plant established at that particular time and place; otherwise it is ‘white’.3 Each pair of black cells is connected by a ‘join’ that represents the association between stems established at two different places and times. Join ‘length’ is the pair of factors (s,t) that describes the distance between stems in space and in time, respectively. Spatio-temporal pattern is detected by comparing the number of joins of each ‘length’ in a particular lattice with the expected number calculated from lattices generated by three different random models. Colonization rates can be estimated if there are particular join classes that occur more frequently than expected.4 Artificially generated lattices were used to examine the effect of background noise on the ability to detect underlying pattern.5 Field data were obtained from a Populus balsamifera clone that was colonizing a grassland. Three belt transects, 1 m wide and up to 13 m in length, were established, and ramets in each 0.5-m interval were aged by tree ring counts. Position and age were used to construct a lattice of stem establishment.6 We were able to discern a pattern both in artificial lattices and in the colonization of P. balsamifera ramets. Ramets took between 1 and 2 years to advance 1 m into the grassland (equivalent to a rate of 0.5–1 m per year).7 Describing plant establishment in space and time with two-factor join count statistics provides a way of measuring the rate of species movement at the scale of the individual.
Canadian Journal of Botany-revue Canadienne De Botanique, 2002
... standing vegetation from a landscape, and initiates highly spatial regeneration processes, li... more ... standing vegetation from a landscape, and initiates highly spatial regeneration processes, like establishment and growth (Houle 1995 ... Determining when intraspecific competition ceases to domi-nate and interspecific competition begins is difficult when dealing with multispecies ...
13. Multiple-Use Management Strategy Evaluation for Coastal Marine Ecosystems Using InVitro AD Mc... more 13. Multiple-Use Management Strategy Evaluation for Coastal Marine Ecosystems Using InVitro AD McDonald, E. Fulton, LR Little, R. Gray, KJ Sains-bury and VD Lyne Abstract The Management Strategy Evaluation (MSE) framework has been applied in a multiple-use setting to ...
Journal of the National Cancer Institute, Dec 1, 2016
Diffuse large B cell lymphoma (DLBCL) comprises multiple molecular and biological subtypes, resul... more Diffuse large B cell lymphoma (DLBCL) comprises multiple molecular and biological subtypes, resulting in a broad range of clinical outcomes. With standard chemoimmunotherapy, there remains an unacceptably high treatment failure rate in certain DLBCL subsets: activated B cell (ABC) DLBCL, double-hit lymphoma defined by the dual translocation of MYC and BCL2, dual protein-expressing lymphomas defined by the overexpression of MYC and BCL2, and older patients and those with central nervous system involvement. The main research challenges for DLBCL are to accurately identify molecular subsets and to determine if specific chemotherapy platforms and targeted agents offer differential benefit. The ultimate goal should be to maximize initial cure rates to improve long-term survival while minimizing toxicity. In particular, a frontline trial should focus on biologically defined risk groups not likely to be cured with cyclophosphamide, doxorubicin, vincristine, and prednisone plus rituximab (R...
Fisheries management operates in an environment characterized by multiple risks. These risks are ... more Fisheries management operates in an environment characterized by multiple risks. These risks are often complementary and can be traded off against each other. An important goal for managers is to develop strategies to minimize the overall risk exposure at minimal cost. We show a simple model that quantifies a range of risks faced by fisheries management agencies in terms of long-term expected budgetary expenditure. The model includes not only the cost a management agency would be expected to incur from overfishing a stock, or from being seen to overfish it, but also the social cost incurred from not achieving its objectives, such as the opportunity cost of foregoing catches and economic returns. These costs can be controlled by adjusting the biomass level targeted by management, or increasing expenditures for data collection to improve the precision of biomass estimates. The overall risk, expressed as the long-term total expected cost to a management agency, depends strongly on the fisheries management objectives, and the emphasis on conservation or economic motives. In general, management under a conservation-oriented objective would reduce risk either by increasing target biomass levels or by expenditure on monitoring and assessment, while a catch-focused objective would seek to lower management costs by reducing expenditure on data collection and assessment. Increased natural stock variability affects the risk of overfishing, and long-term expected costs as the ability to make a meaningful estimate of biomass declines. Management of catch-focused fisheries would reduce the biomass target as stock variability increases, because the benefit of catches are seen to outweigh the cost, or risk of being overfished. The model provides the basis for more extensive risk analyses, and serves as a simple lesson that the consequences of reducing the short-term costs associated with managing a fishery can come with a concomitant increase in overall risk. Keywords: false-negative estimation error, false-positive estimation error, fisheries management cost, risk – cost – catch trade-off, risk equivalency.
Balancing bio-economic risks and high profit expectations is often a major concern in fisheries m... more Balancing bio-economic risks and high profit expectations is often a major concern in fisheries management. We examine this trade-off in the context of the Australian Northern Prawn Fishery (NPF). The fishery derives its revenue from different prawn species with different dynamics and recruitment processes. A multi-species bio-economic and stochastic model is used to examine the trade-offs between mean profitability of the fishery and its variance, under a range of economic scenarios, fishing capacities and distributions of fishing effort across the various sub-fisheries that comprise the NPF. Simulation results show that the current fishing strategy diversifying catch across sub-components of the fishery entails a compromise between expected performance and risk. Furthermore, given the current economic conditions, increases in fleet size would improve the expected economic performance of the fishery, but at the cost of increased variability of this performance.
We present a modelling approach to rapidly assess the effect of management decisions on ecologica... more We present a modelling approach to rapidly assess the effect of management decisions on ecological problems and demonstrate its use in fishery management. Each stage of the approach is controlled by a Graphical User Interface which allows a team of non-expert modellers to compare the outcomes of multiple model simulations and to decide what further simulation is needed.A distinguishing feature of the method is that it allows the goal of the management strategies to arise as a result of the interaction between the user and the model, rather than being defined a priori, as well as to change during the process in response to the information and the insight such modelling may provide. We envisage that a management team, rather than a single user, may also employ the method as an avenue for communication, in order to discuss the potentially conflicting aspects of different model outcomes along the path to finding workable compromises. We discuss an application of the approach to the sustainable management of a recreational fishery in a marine park in Western Australia.
This paper deals with the sustainable management of a renewable resource based on individual and ... more This paper deals with the sustainable management of a renewable resource based on individual and transferable quotas (ITQs) when agents differ in terms of harvesting costs or catch capability. In a dynamic bio-economic model, we determine the feasibility conditions under which a fishery manager can achieve sustainability objectives which simultaneously account for stock conservation, economic efficiency and maintenance of fishing activity for the agents along time. We show how the viability of quota management strategies based on ITQ depends on the degree of heterogeneity of users in the fishery, the current status and the dynamics of the stock together with the selection of TAC schedules. In particular for a given stock, we compute the maximin effort for a given set of agents and we derive the maximal number of active agents for a given guaranteed effort. An application to the nephrops fishery in the Bay of Biscay illustrates the results.
Abstract Spatial management measures in the form of no-take areas used in fisheries management c... more Abstract Spatial management measures in the form of no-take areas used in fisheries management can provide a buffer against catastrophic events. Dynamic area closures, like rotational closures, have also been used as a management tool particularly for sessile organisms. In this study, bioeconomic models are developed to investigate dynamic closure strategies for use as a management tool in the harvest of a metapopulation consisting of two local sub-populations. The models provide an optimal strategy that maximises the sum of discounted net returns with a fixed harvest level [i.e. total allowable catch (TAC)] by opening and closing the sub-populations of a metapopulation, subject to random negative catastrophic effects. Results showed the optimal policy for opening and closing a single exploited population depends on the degree and pattern of migration between it and other sub-populations. When the harvest or TAC can be applied to either sub-population, the optimal closure strategy depends on the abundance of both populations, crucially, even if they are biologically independent. The results provide insights into the management of stochastically fluctuating populations including more mobile species that are frequently not subject to no-take controls.
1 Ecological patterns in space and time have been well documented using interval variables such a... more 1 Ecological patterns in space and time have been well documented using interval variables such as plant density. In this paper, we use join Page: 1Is the text OK: join count statistics to examine spatio-temporal patterns in a binary variable, plant establishment.2 Establishment along a belt transect is represented as a grid or lattice in which each cell denotes a particular quadrat in a particular year. A cell is ‘black’ if a plant established at that particular time and place; otherwise it is ‘white’.3 Each pair of black cells is connected by a ‘join’ that represents the association between stems established at two different places and times. Join ‘length’ is the pair of factors (s,t) that describes the distance between stems in space and in time, respectively. Spatio-temporal pattern is detected by comparing the number of joins of each ‘length’ in a particular lattice with the expected number calculated from lattices generated by three different random models. Colonization rates can be estimated if there are particular join classes that occur more frequently than expected.4 Artificially generated lattices were used to examine the effect of background noise on the ability to detect underlying pattern.5 Field data were obtained from a Populus balsamifera clone that was colonizing a grassland. Three belt transects, 1 m wide and up to 13 m in length, were established, and ramets in each 0.5-m interval were aged by tree ring counts. Position and age were used to construct a lattice of stem establishment.6 We were able to discern a pattern both in artificial lattices and in the colonization of P. balsamifera ramets. Ramets took between 1 and 2 years to advance 1 m into the grassland (equivalent to a rate of 0.5–1 m per year).7 Describing plant establishment in space and time with two-factor join count statistics provides a way of measuring the rate of species movement at the scale of the individual.
Canadian Journal of Botany-revue Canadienne De Botanique, 2002
... standing vegetation from a landscape, and initiates highly spatial regeneration processes, li... more ... standing vegetation from a landscape, and initiates highly spatial regeneration processes, like establishment and growth (Houle 1995 ... Determining when intraspecific competition ceases to domi-nate and interspecific competition begins is difficult when dealing with multispecies ...
13. Multiple-Use Management Strategy Evaluation for Coastal Marine Ecosystems Using InVitro AD Mc... more 13. Multiple-Use Management Strategy Evaluation for Coastal Marine Ecosystems Using InVitro AD McDonald, E. Fulton, LR Little, R. Gray, KJ Sains-bury and VD Lyne Abstract The Management Strategy Evaluation (MSE) framework has been applied in a multiple-use setting to ...
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