Copyright (c) 2010 Berkeley Electronic Press All rights reserved. http://www.bepress.com Recent documents in The Berkeley Electronic Press en-us Tue, 09 Feb 2010 00:57:52 PST 3600 http://www.bepress.com/jhsem/vol7/iss1/9 http://www.bepress.com/jhsem/vol7/iss1/9 Mon, 08 Feb 2010 09:11:34 PST Kelly Phelan Emergency Management http://www.bepress.com/jafio/vol8/iss1/art2 http://www.bepress.com/jafio/vol8/iss1/art2 Mon, 08 Feb 2010 08:48:07 PST In this paper we empirically analyze whether prices serve as signals. Specifically, and following the hypothesis by Bagwell and Riordan (1991), we examine whether (1) higher quality and (2) low consumer information levels about quality are associated with prices that are above the full information equilibrium. We refer to two price samples of identical wines and analyze the difference between both. The first sample consists of prices for informed wholesalers who can taste the wines before purchase. The second sample comprises retail prices for the imperfectly informed public. We find support for the Bagwell-Riordan model, i.e., price signals respond positively to wine quality and negatively to increasing information. For our sample, the information effect by far dominates the quality effect. Hubert Schnabel wine economics industrial organization wine pricing signaling retail margin information http://www.bepress.com/uwbiostat/paper357 http://www.bepress.com/uwbiostat/paper357 Fri, 05 Feb 2010 14:49:02 PST After a non-inferiority clinical trial, a new therapy may be accepted as effective, even if its treatment effect is slightly smaller than the current standard. It is therefore possible that, after a series of trials where the new therapy is slightly worse than the preceding drugs, an ineffective or harmful therapy might be incorrectly declared efficacious; this is known as "bio-creep." Several factors may influence the rate at which bio-creep occurs, including the distribution of the effects of the new agents being tested and how that changes over time, the choice of active comparator, the method used to model the variability of the estimate of the effect of the active comparator, and changes in the effect of the active comparator from one trial to the next (violations of the constancy assumption). We performed a simulation study to examine which of these factors might lead to bio-creep and found that bio-creep was rare, except when the constancy assumption was violated. Siobhan Everson-Stewart General Biostatistics http://www.bepress.com/jdpa/vol3/iss1/art1 http://www.bepress.com/jdpa/vol3/iss1/art1 Fri, 05 Feb 2010 12:21:53 PST Over the last decade there have been several large-scale efforts to leverage the law to encourage substance-abusing offenders to enter treatment. A routine practice has developed in most states in which offenders undergo an assessment for drug abuse or dependence, and based on their self-reported behavior, those deemed to have a substance use disorder are referred to treatment programs. The problem with applying the assessment-treatment model in correctional systems is that both components of this approach are seriously flawed. An alternative model, using regular random testing coupled with modest sanctions, relies on offender observed behavior rather than self report, to signal need for treatment services. Many offenders are able to desist from drug use without treatment. This reallocation of resources creates greater opportunity to provide more-intensive treatment services to those who really need it. This paper proposes replacing the traditional assess-and-treat approach with an alternative model that bases treatment decisions on observed behavior: the behavioral triage model. Angela Hawken Drug Policy http://www.bepress.com/ev/vol7/iss1/art3 http://www.bepress.com/ev/vol7/iss1/art3 Fri, 05 Feb 2010 11:58:18 PST At the international level, a global carbon price is a better form of commitment to reduce carbon emissions than a system of national caps. Peter Cramton and Steven Stoft outline a price-based approach that is simple, effective, and remarkably affordable. Peter Cramton Q54 http://www.bepress.com/feem/paper400 http://www.bepress.com/feem/paper400 Fri, 05 Feb 2010 05:07:06 PST This paper reports an original economic valuation of the impact of climate change on the provision of forest regulating services in Europe. To the authors' knowledge the current paper represents the first systematic attempt to estimate human well-being losses with respect to changes in biodiversity and forest regulating services that are directly driven by climate change. First, selected 34 European countries are grouped by their latitude intervals to capture the differentiated regional effects of forests in response to climate change. Moreover, the future trends of forest areas and stocked carbon in 2050 are projected through the construction and simulation of global circulation models such as HADMC3 following four different future developing paths described by the four IPCC scenarios. Finally, the valuation exercise is anchored in an ecosystem service based approach, involving the use of general circulation models and integrated assessment models. Our findings address two dimensions in the evaluation of climate impacts on European forests: Firstly, future projections yield different states of the world depending upon the IPCC scenario adopted. Secondly, spatial issues matter in an assessment of the distributional impacts of climate change, as these impacts are not distributed in a uniform way across the European countries under consideration. Paulo A.L.D. Nunes http://www.bepress.com/feem/paper399 http://www.bepress.com/feem/paper399 Fri, 05 Feb 2010 03:52:34 PST This paper investigates how the ownership and the procedure for the selection of firms operating in the local public transport sector affect their productivity. In order to compare different institutional regimes, we carry out a comparative analysis of 72 companies operating in large European cities. This allows us to consider firms selected either through competitive tendering or negotiated procedures. The analysis of the data on 77 European firms over the period 1997-2006 indicates that firms operate under constant returns to scale. Retrieving the residuals we obtain a measure of total factor productivity, which we regress on firm and city characteristics. We find that when firms are totally or partially in public hands their productivity is lower. Moreover, firms selected through competitive tendering display higher total factor productivity. Marcella Nicolini http://www.bepress.com/feem/paper398 http://www.bepress.com/feem/paper398 Fri, 05 Feb 2010 03:36:30 PST The potential of traditional natural resources management for biodiversity conservation and the improvement of sustainable rural livelihoods is no longer in doubt. In sub-Saharan Africa, extensive habitat destruction, degradation, and severe depletion of wildlife, which have seriously reduced biodiversity and undermined the livelihoods of many people in rural communities, have been attributed mainly to the erosion of traditional strategies for natural resources management. In Ghana, recent studies point to an increasing disregard for traditional rules and regulations, beliefs and practices that are associated with natural resources management. Traditional natural resources management in many typically indigenous communities in Ghana derives from changes in the perceptions and attitudes of local people towards tumi, the traditional belief in super natural power suffused in nature by Onyame, the Supreme Creator Deity. However, this is closely entwined with ecological, demographic and economic factors. Whilst these factors have driven the need to over-exploit natural resources, a situation which threatens the sustainability of community forests including sacred groves, religion has been used to justify such actions. This paper explores changes in tumi and the sustainability of sacred groves in the forest-savanna transitional zone in Ghana. It would confirm that changes in traditional animist beliefs, such as tumi, which informs the worldview of local people and underlies traditional natural resources management, is mainly due to the advances made by Christianity and Islam. Paul Sarfo-Mensah http://www.bepress.com/feem/paper397 http://www.bepress.com/feem/paper397 Fri, 05 Feb 2010 03:28:38 PST Bayesian networks (BNs) have been increasingly applied to support management and decision-making processes under conditions of environmental variability and uncertainty, providing logical and holistic reasoning in complex systems since they succinctly and effectively translate causal assertions between variables into patterns of probabilistic dependence. Through a theoretical assessment of the features and the statistical rationale of BNs, and a review of specific applications to ecological modelling, natural resource management, and climate change policy issues, the present paper analyses the effectiveness of the BN model as a synthesis framework, which would allow the user to manage the uncertainty characterising the definition and implementation of climate change adaptation policies. The review will let emerge the potentials of the model to characterise, incorporate and communicate the uncertainty, with the aim to provide an efficient support to an informed and transparent decision making process. The possible drawbacks arising from the implementation of BNs are also analysed, providing potential solutions to overcome them. Michela Catenacci http://www.bepress.com/feem/paper396 http://www.bepress.com/feem/paper396 Fri, 05 Feb 2010 03:23:52 PST This paper explores optimal environmental tax policy under which duopoly firms strategically choose the location of their plants in a simple three-stage game. We examine how the relationship between the optimal emission tax and the choice of location of duopoly firms affects the welfare of the home country. We characterize the relationship between the optimal emission tax and the fixed cost, depending on the degree of environmental damage from production. Finally, we show the existence of asymmetric equilibrium in which either firm chooses relocation of its plant even if the duopoly firms are identical ex ante. Masako Ikefuji http://www.bepress.com/feem/paper395 http://www.bepress.com/feem/paper395 Fri, 05 Feb 2010 03:18:57 PST A government bargains a mutually convenient agreement with a multinational corporation to extract a natural resource. The corporation bears the initial investment and earns as a return a share on the profits. The host country provides access and guarantee conditions of operation. Being the investment totally sunk, the corporation must account in its plan not only for uncertainty on market conditions but also for the threat of nationalization. In a real options framework where the government holds an American call option on nationalization we show under which conditions a Nash bargaining is feasible and leads to attain a cooperative agreement maximizing the joint venture surplus. We find that the threat of nationalization does not affect the investment time trigger but only the feasible bargaining set. Finally, we show that the optimal sharing rule results from the way the two parties may differently trade off rents with option value. Luca Di Corato http://www.bepress.com/feem/paper394 http://www.bepress.com/feem/paper394 Fri, 05 Feb 2010 03:12:05 PST Climate-economy models aiming at quantifying the costs and effects of climate change impacts and policies have become important tools for climate policy decision-making. Although there are several important dimensions along which models differ, this paper focuses on a key component of climate change economics and policy, namely technical change. This paper tackles the issues of whether technical change is biased towards the energy sectors, the importance of the elasticity of substitution between factors in determining this bias and how mitigation policy is likely to affect it. The analysis is performed using the World Induced Technical Change model, WITCH. Three different versions of the model are proposed. The starting set-up includes endogenous technical change only in the energy sector. A second version introduces endogenous technical change in both the energy and non-energy sectors. A third version of the model embodies different sources of technical change, namely R&D and human capital. Although different formulations of endogenous technical change have only a minor influence on climate policy costs, the macroeconomic effects on knowledge and human capital formation can vary greatly. Enrica De Cian http://www.bepress.com/feem/paper393 http://www.bepress.com/feem/paper393 Fri, 05 Feb 2010 03:06:25 PST We construct a strategic trade model of an international duopoly, whereby production by exporting firms generates a local pollutant. Governments use environmental policies, i.e., an emissions standard or a tax, to control pollution and for rent shifting purposes. Contrary to their firm, however, governments are unable to perfectly foresee the actual level of demand, the cost of abatement and the damage caused from pollution. Under these modes of uncertainty we derive sufficient conditions under which the governments optimally choose an emissions tax over an emissions standard. Panos Hatzipanayotou http://www.bepress.com/feem/paper392 http://www.bepress.com/feem/paper392 Fri, 05 Feb 2010 03:00:44 PST In this paper we examine an alternative policy scenario, where governments allow polluting firms to trade permits in a strategic environmental policy model. We demonstrate, among other things, that with no market power in the permits market, governments of the exporting firms do not have an incentive to under-regulate pollution in order to become more competitive. This strategic effect is reversed and leads to a welfare level closer to the cooperative one and strictly higher to that when permits are non-tradable. Allowing for market power in the permits market, the incentive to under-regulate pollution re-appears regardless of whether permits are tradable or not. With tradable permits, however, the incentive to under-regulate pollution is comparatively weaker relative to the case of non-tradable permits. This entails potential benefits for the exporting firms and countries since the prisoners' dilemma is moderated. Panos Hatzipanayotou http://www.bepress.com/feem/paper391 http://www.bepress.com/feem/paper391 Fri, 05 Feb 2010 02:56:03 PST The present paper analyses the expenditure behavior of Albanian families. The objective is to cast some light upon the relationship between education expenditure and the volume of remittances, sent from abroad by household members. To assess the existence of an education enhancing effect of remittances, an Engel curve framework is employed, where heterogeneity in interests or in bargaining power among the members within the households is assumed. The empirical estimation accounts for the censored nature of the education expenditure through using Heckman two-step as well as a semiparametric model for sample selection. Finally, quintile regression analysis is employed to investigate whether migrants' remittances have a differentiated effect on various quantiles of the conditional distribution of the education consumption. Cristina Cattaneo http://www.bepress.com/cjpp/vol2/iss2/16 http://www.bepress.com/cjpp/vol2/iss2/16 Thu, 04 Feb 2010 13:38:57 PST Richard Gordon http://www.bepress.com/bejm/vol10/iss1/art3 http://www.bepress.com/bejm/vol10/iss1/art3 Thu, 04 Feb 2010 09:34:12 PST The communication of ideas fosters technological progress and prevents regress. This paper develops a growth model wherein an economy's technology is endogenous to agents' communication decisions. In equilibrium, there is too little communication and insufficient risk-taking relative to the first best. The model can generate an abrupt take-off of output growth without an exogenous "catastrophe." A numerical example illustrates such a take-off. In that example, the endogenous fall in the cost of communication leads to the acceleration of the growth rate of output by facilitating the transmission of knowledge and by encouraging risk-taking. Romans Pancs O40 D90 http://www.bepress.com/scid/vol2/iss1/art1 http://www.bepress.com/scid/vol2/iss1/art1 Thu, 04 Feb 2010 08:31:10 PST Most randomized efficacy trials of interventions to prevent HIV or other infectious diseases have assessed intervention efficacy by a method that either does not incorporate baseline covariates, or that incorporates them in a non-robust or inefficient way. Yet, it has long been known that randomized treatment effects can be assessed with greater efficiency by incorporating baseline covariates that predict the response variable. Tsiatis et al. (2007) and Zhang et al. (2008) advocated a semiparametric efficient approach, based on the theory of Robins et al. (1994), for consistently estimating randomized treatment effects that optimally incorporates predictive baseline covariates, without any parametric assumptions. They stressed the objectivity of the approach, which is achieved by separating the modeling of baseline predictors from the estimation of the treatment effect. While their work adequately justifies implementation of the method for large Phase 3 trials (because its optimality is in terms of asymptotic properties), its performance for intermediate-sized screening Phase 2b efficacy trials, which are increasing in frequency, is unknown. Furthermore, the past work did not consider a right-censored time-to-event endpoint, which is the usual primary endpoint for a prevention trial. For Phase 2b HIV vaccine efficacy trials, we study finite-sample performance of Zhang et al.'s (2008) method for a dichotomous endpoint, and develop and study an adaptation of this method to a discrete right-censored time-to-event endpoint. We show that, given the predictive capacity of baseline covariates collected in real HIV prevention trials, the methods achieve 5-15% gains in efficiency compared to methods in current use. We apply the methods to the first HIV vaccine efficacy trial. This work supports implementation of the discrete failure time method for prevention trials. Min Zhang Clinical Trial http://www.bepress.com/cjpp/vol2/iss2/15 http://www.bepress.com/cjpp/vol2/iss2/15 Wed, 03 Feb 2010 10:44:22 PST "Are you ready to put on your white wigs?" That question increasingly is being posed to many everyday Californians, as the Golden State considers if a constitutional convention composed of regular folks might hold the solution to California's ongoing political and budgetary woes. With state government in Sacramento seemingly frozen in place, a group of California leaders formed RepairCalifornia.org and have filed a voter initiative to create a constitutional convention to address the state's deeply entrenched structural problems. But this would be no ordinary convention. Just over half of the 460 or so participants would be "citizen delegates," regular people who have been selected to convene a broad cross-section of California. Steven Hill http://www.bepress.com/cjpp/vol2/iss2/14 http://www.bepress.com/cjpp/vol2/iss2/14 Wed, 03 Feb 2010 10:44:21 PST Gabriella Holt http://www.bepress.com/cjpp/vol2/iss2/13 http://www.bepress.com/cjpp/vol2/iss2/13 Wed, 03 Feb 2010 10:44:19 PST While constitutional reform is essential for addressing the dysfunctionality that characterizes California government, it probably cannot be accomplished by means of a convention. Why? Because the same forces that have created our governance problems would be in a position to make sure their interests are protected in the convention process. A better approach would be to target strategic reforms through a series of voter initiatives that would mitigate the influence of special interests.Among the many strategic reforms needed, two of the most important would be (1) to increase the capacity of the legislature to make wise decisions, and (2) to create a decision-making process that would allow wise choices on the part of individual legislators to translate into collective action by the legislature. John Sweeten http://www.bepress.com/cjpp/vol2/iss2/12 http://www.bepress.com/cjpp/vol2/iss2/12 Wed, 03 Feb 2010 10:44:18 PST Gloria Duffy http://www.bepress.com/cjpp/vol2/iss2/11 http://www.bepress.com/cjpp/vol2/iss2/11 Wed, 03 Feb 2010 10:44:17 PST B. Timothy Gage http://www.bepress.com/cjpp/vol2/iss2/10 http://www.bepress.com/cjpp/vol2/iss2/10 Wed, 03 Feb 2010 10:44:16 PST Robert W. Naylor http://www.bepress.com/cjpp/vol2/iss2/9 http://www.bepress.com/cjpp/vol2/iss2/9 Wed, 03 Feb 2010 10:44:15 PST Peter Schrag http://www.bepress.com/cjpp/vol2/iss2/8 http://www.bepress.com/cjpp/vol2/iss2/8 Wed, 03 Feb 2010 10:44:14 PST Tom Campbell http://www.bepress.com/cjpp/vol2/iss2/7 http://www.bepress.com/cjpp/vol2/iss2/7 Wed, 03 Feb 2010 10:44:12 PST California's current budget process fails to accomplish any of the goals a budget should. It does not maintain aggregate fiscal control. The budget fails to achieve allocative efficiency by targeting resources to programs that address the sectors of the state economy that would most benefit from additional resources. In addition, the budget is frequently tardy. A Constitutional Convention could fix these problems. Stuart Kasdin http://www.bepress.com/cjpp/vol2/iss2/6 http://www.bepress.com/cjpp/vol2/iss2/6 Wed, 03 Feb 2010 10:23:46 PST We study the effects of California's Tax and Expenditure Limitations, especially Proposition 13. We find that Proposition 13 was indeed effective at reducing both ad valorem property taxes per capita and total state and local taxes per capita, at least in the short run. We further argue that there have been unintended secondary effects that have resulted in an increased tax burden, undermining the aims of Proposition 13. To circumvent the limits imposed by Proposition 13, the state has drastically increased nonguaranteed debt, has privatized the public fisc, and has devolved the authority to lay and collect taxes and to spend the proceeds so gained. The devolution of authority has been among the swiftest growing aspects of government finance in California, to a far greater extent than in other states. Lastly, we argue that the new tax and spending authorities that have been created to circumvent Proposition 13 have led to a reduction in government transparency and accountability and pose an increasing threat to our democracy. Colin H. McCubbins http://www.bepress.com/cjpp/vol2/iss2/5 http://www.bepress.com/cjpp/vol2/iss2/5 Wed, 03 Feb 2010 10:23:44 PST In a survey of over 1,000 Californians, we found substantial divides in public opinion on issues related to constitutional change. Beyond partisan differences, there are racial and ethnic divides as well as unexpected differences between counties. Latinos and Asian-Americans (the growing "new" California electorate) are less dissatisfied with the initiative process, less eager to change California's constitution to restrict direct democracy, and more likely to be unsure about their views on constitutional reform than whites and African-Americans (the "old" California electorate). This article also explores surprising geographic patterns in support and opposition to proposed reforms, such as the elimination of the two-thirds requirement for passing the state budget. Mike Binder http://www.bepress.com/cjpp/vol2/iss2/4 http://www.bepress.com/cjpp/vol2/iss2/4 Wed, 03 Feb 2010 10:23:43 PST Over the past 50 years, partisan polarization--the ideological distance between the typical Democratic and the average Republican legislator--has widened in California. This article asks whether growing polarization has led to increasing legislative gridlock. Borrowing the approach of the congressional literature to collect a new measure of gridlock by using journalistic sources, it charts the percentage of major issues that state leaders were unable to resolve in the first year of every gubernatorial term from 1931 to 2004. It finds that divided government dramatically increases the level of gridlock, that legislative party polarization exerts no direct effect, but that higher levels of polarization magnify the impact of divided government on gridlock. Thad B. Kousser http://www.bepress.com/cjpp/vol2/iss2/3 http://www.bepress.com/cjpp/vol2/iss2/3 Wed, 03 Feb 2010 10:23:41 PST Over the past 45 years, 15 American states have held constitutional conventions to confront the pressing concerns of the day. These conventions pursued markedly different paths toward constitutional reform, and achieved widely varying degrees of success. The experience of these states provides important insights for policymakers and citizens that can help identify both models worthy of emulation and the potential pitfalls of reform. The likely success of state constitutional conventions appears tied not to the identity of delegates or the selection mechanism used to recruit them but rather to the scope of the possible revisions and the way in which amendments are presented to voters for final approval. In addition, recent political history suggests that voters remain reluctant to empanel conventions to pursue wholesale reform, rejecting every call for a constitutional convention that has appeared on a state ballot since 1990. Vladimir Kogan http://www.bepress.com/cjpp/vol2/iss2/2 http://www.bepress.com/cjpp/vol2/iss2/2 Wed, 03 Feb 2010 10:23:40 PST With all that is at stake in reforming the government of the nation's largest state, with responsibility for the welfare of 38 million Californians, we know very little about how to make a constitutional convention work. How large should the convention be? Should delegates be elected or appointed? What issues should be on the agenda? How can the convention delegates obtain expert information? Who will organize and lead the convention? Remarkably, there is virtually no discussion of the far more common experience by which local and some state governments in California and throughout the nation have reformed governance structures: the charter reform commission. Such commissions have routinely dealt with these issues for more than a hundred years and have managed to update and adapt municipal government with great success. Raphael Sonenshein http://www.bepress.com/cjpp/vol2/iss2/1 http://www.bepress.com/cjpp/vol2/iss2/1 Wed, 03 Feb 2010 10:23:39 PST Fourteen years after the demise of the last serious attempt to revise California's much maligned Constitution, the effort has been renewed again. California Forward, a foundation funded bipartisan coalition, has proposed a slate of structural reforms that could be adopted as either legislative (LCAs) or as initiative (ICAs) constitutional amendments. Reform California, sponsored by the Bay Area Council (a business sponsored public policy advocacy organization for the nine counties of the Bay Area) has proposed a radical new form of constitutional convention that would bypass the legislature and rely on delegates chosen by local government and lottery. Bruce Cain http://www.bepress.com/jhsem/vol7/iss1/8 http://www.bepress.com/jhsem/vol7/iss1/8 Wed, 03 Feb 2010 10:14:09 PST Robert Lloyd Ditch Emergency Management http://www.bepress.com/ijcre/vol8/A32 http://www.bepress.com/ijcre/vol8/A32 Wed, 03 Feb 2010 09:58:27 PST A 2D model of a confined impinging jets mixer having the same geometry of the mixing chamber of a Reaction Injection Moulding, RIM, machine is introduced for the flow field simulation in a Computational Fluid Dynamics, CFD, code. From the CFD simulations the flow field structures and dynamics are clearly established. In addition, the numerical parameters affecting the 2D model simulations are studied, setting for each parameter a validity range. The 2D model is validated and used in the study of some operational parameters: the Reynolds number, the Froude number and the momentum ratio between the opposed jets. The validation of the CFD simulations is also made by comparison with experimental results. The limitations of the 2D model, for simulating the actual 3D flow field, are assessed; from the 2D/3D comparison, it is clearly shown that the introduced model can predict the main flow field features. Ricardo J. Santos Computational Fluid Dynamics http://www.bepress.com/ijcre/vol8/A31 http://www.bepress.com/ijcre/vol8/A31 Wed, 03 Feb 2010 09:58:23 PST The present work is focused on the aqueous-phase reforming of ethylene glycol at 500 K. The influence of the system pressure (27 to 36 bar) and the catalyst weight/ethylene glycol flow rate ratio has been studied using a Pt/Al2O3 research catalyst. A comparison of the latter with a Ni/Al coprecipitated catalyst showed a significant influence on hydrogen and alkane selectivities. Ana Valiente http://www.bepress.com/ijcre/vol8/A30 http://www.bepress.com/ijcre/vol8/A30 Wed, 03 Feb 2010 09:58:19 PST This paper concerns the cleaning of the hot gas produced by steam gasification of biomass in a fluidized bed. The cleaning takes place in a catalytic filter candle device placed directly in the freeboard of the bed. Such integration results in a compact processing unit and increased thermal efficiency; the result of the cleaning being carried out directly at the reactor outlet temperature. It thus lends itself to exploitation in distributed power generation systems utilizing renewable energy sources. Results are reported for runs performed in a bench scale fluidized bed steam gasifier fitted with a single full-size catalytic candle filter. Tar and particulates in the product gas were sampled in accord with technical specification CEN/TS 15439 with analysis by UV and fluorescence spectroscopy. Sergio Rapagną Engineering: Chemical Engineering: Catalysis and Reaction Engineering http://www.bepress.com/ijcre/vol8/A29 http://www.bepress.com/ijcre/vol8/A29 Wed, 03 Feb 2010 09:58:15 PST A Modified Activated Sludge Model No.1 (M-ASM1), including six COD components (SI, SS, XI, XS, XH and SO) and three biochemical processes (aerobic growth of heterotrophs, aerobic decay of heterotrophs and hydrolysis of entrapped organics) is used to simulate the anaerobic hydrolysis-aeration- sedimentation treatment series in a full-scale textile dyeing wastewater treatment plant with an influent flowrate of 200,000 m3/d. M-ASM1 has the following characteristics: (1) the effect of temperature variation on biochemical reactions is included; (2) adding a parameter: η. Using this parameter, the anaerobic hydrolysis tank and the aerobic initial compartments in which the dissolved oxygen concentrations are equal to "0 mg/L" can be differentiated; (3) the oxygen transfer coefficient KLa is excluded. Namely, as long as inputting the aeration flowrate, the pressure in the aeration pipe and other running data on air supply into this model, M-ASM1 can simulate the oxygen concentrations of each compartment in a plug-flow aeration tank. Jingjie Yu environmental engineering reactor modeling http://www.bepress.com/ijcre/vol8/A28 http://www.bepress.com/ijcre/vol8/A28 Wed, 03 Feb 2010 09:58:11 PST This paper presents a Photovoltaic (PV) simulation system powering a reverse osmosis (RO) desalination unit with no energy recovery device (ERD). The simulation is carried out using commercial software, Transient System Simulation (TRNSYS®). The PV system consists on solar panels (Siemens SM55) with rated power of 55 W, connected to a storage battery via DC-DC charge controller. The load of this system is a pump, which provides the RO system with feed water. The RO unit is composed of one Filmtec spiral wound membrane. Simulation results for fresh water production showed that with a continuous feed of 1.5 m3h-1, a total capacity production of 110 m3 per year can be achieved. The effect of the main parameters in desalinated water production capacity showed that with the increase of the raw water feed flow and the PV surface, the monthly fresh water production increases. They also showed that with the increase of raw water salinity, the fresh water production decreases. This work is validated with literature experimental results. Rym Chaker Water Desalination using Solar Energy http://www.bepress.com/ijcre/vol8/A27 http://www.bepress.com/ijcre/vol8/A27 Wed, 03 Feb 2010 09:58:07 PST Heat supplement is necessary for FCC gasoline upgrading processes to keep the heat balance of reaction-regeneration system, while excess heat would be removed in FCC process due to the processing of heavy feedstock. Combining gasoline upgrading processes with FCC process can realize the heat coupling so as to achieve the maximum energy utilization. In this paper, the heat balance calculations of a commercial FCC unit and a FCC gasoline aromatization process were carried out, and the feasibility as well as the way to accomplish the heat coupling for the two processes was investigated. The results showed that the coked aromatization catalysts could be heated to the desired temperature by the direct contact with the hot regenerated FCC catalysts. The pilot experiment and CFD simulation was carried out to investigate the flow behavior and heat transfer of the direct coupling system of FCC process and FCC gasoline aromatization process. The results indicated that the well-mixing and efficient heat transfer between FCC catalysts and aromatization catalysts, as well as the sufficient regeneration of aromatization catalysts, could be achieved at appropriate operating conditions. Xingying Lan http://www.bepress.com/jhubiostat/paper205 http://www.bepress.com/jhubiostat/paper205 Wed, 03 Feb 2010 08:19:28 PST For a better understanding of the biology of an organism a complete description is needed of all regions of the genome that are actively transcribed. Tiling arrays can be used for this purpose. Such arrays allow the discovery of novel transcripts and the assessment of differential expression between two or more experimental conditions such as genotype, treatment, tissue, etc. Much of the initial methodological efforts were designed for transcript discovery, while more recent developments also focus on differential expression. To our knowledge no methods for tiling arrays are described in the literature that can both assess transcript discovery and identify differentially expressed transcripts, simultaneously. The wavelet based functional model developed in this paper is designed to fill this methodological void. As opposed to existing methods, our statistical framework also permits a natural integration of preprocessing into the standard statistical analysis flow of tiling array data. We use Johnson transformations, which are based on cumulants, for computing false discovery rates (FDRs) and Bayesian credibility intervals for the estimates of the effect functions within the data space. A case study illustrates that our model is well suited for a simultaneous assessment of transcript discovery and differential expression, while remaining competitive with methods that perform only one of these tasks. Lieven Clement Computational Biology/Bioinformatics http://www.bepress.com/bejeap/vol10/iss1/art7 http://www.bepress.com/bejeap/vol10/iss1/art7 Wed, 03 Feb 2010 02:27:42 PST This article considers how legal status affects agricultural labor market outcomes and food prices. Using both propensity score matching and treatment effects regression analysis, undocumented immigrants are found to make 5 to 6% less on average and to have significantly lower probabilities of aid program participation than their documented immigrant counterparts. Magnitudes of differences depend on the permanence of legal status, with naturalized citizens and green card holders benefiting more from their legal status than those with other forms of work authorization. Results suggest that a new program granting amnesty to undocumented immigrant farmworkers, reminiscent of the Seasonal Agricultural Worker program under the Immigration Reform and Control Act, would have minimal effects on farmworker outcomes especially in the short term, and that if employers pass labor cost increases to consumers via food prices, effects on consumers would be similarly minimal. Anita Alves Pena J31 J43 O15 http://www.bepress.com/cppm/vol5/iss1/6 http://www.bepress.com/cppm/vol5/iss1/6 Tue, 02 Feb 2010 20:55:38 PST This work aims to present a detailed study on a commercial double-effect tomato paste evaporation system. The modeling equations formulated for process simulation belong to backward feeding arrangement. Open-loop process dynamics has been studied by rigorous simulation of the model structure. In the next, three multi-loop control schemes, namely conventional proportional integral (PI), gain-scheduled PI (GSPI) and nonlinear PI (NLPI), have been synthesized for the sample process. Finally, several simulation experiments have been conducted to investigate the comparative closed-loop performance based on set point tracking and disturbance rejection. Praveen Yadav Modeling simulation and control http://www.bepress.com/uwbiostat/paper356 http://www.bepress.com/uwbiostat/paper356 Tue, 02 Feb 2010 12:25:48 PST Sequential analysis is frequently employed to address ethical and financial issues in clinical trials. Sequential analysis may be performed using standard group sequential designs, or, more recently, with adaptive designs that use estimates of treatment effect to modify the maximal statistical information to be collected. In the general setting in which statistical information and clinical trial costs are functions of the number of subjects used, it has yet to be established whether there is any major efficiency advantage to adaptive designs over traditional group sequential designs. In survival analysis, however, statistical information (and hence efficiency) is most closely related to the observed number of events, while trial costs still depend on the number of patients accrued. As the number of subjects may dominate the cost of a trial, an adaptive design that specifies a reduced maximal possible sample size when an extreme treatment effect has been observed may allow early termination of accrual and therefore a more costefficient trial. We investigate and compare the tradeoffs between efficiency (as measured by average number of observed events required), power, and cost (a function of the number of subjects accrued and length of observation) for standard group sequential methods and an adaptive design that allows for early termination of accrual. We find that when certain trial design parameters are constrained, an adaptive approach to terminating subject accrual may improve upon the cost efficiency of a group sequential clinical trial investigating time-to-event endpoints. However, when the spectrum of group sequential designs considered is broadened, the advantage of the adaptive designs is less clear. Sarah C. Emerson Clinical Trials http://www.bepress.com/uwbiostat/paper355 http://www.bepress.com/uwbiostat/paper355 Tue, 02 Feb 2010 12:25:47 PST The receiver operating characteristic (ROC) curve is a tool of particular use in disease status classification with a continuous medical test (marker). A variety of statistical regression models have been proposed for the comparison of ROC curves for different markers across covariate groups. A full parametric modeling of the marker distribution has been generally found to be overly reliant on the strong parametric assumptions. Pepe (2003) has instead developed parametric models for the ROC curve that induce a semi-parametric model for the marker distributions. The estimating equations proposed for use in these ROC-GLM models may differ from commonly used estimating equations in those same probability models. In this paper, we investigate the analysis of the power ROC curve when based on the parametric exponential model and the broader semi-parametric proportional hazards probability model. In the case of the latter, we consider estimating equations derived from the usual partial likelihood methods in time-to-event analyses and the ROC-GLM approach of Pepe, et al. In exploring the robustness of these ROC analysis approaches to violations of the distributional assumptions, we find that the ROC-GLM estimating equation provides an extra measure of robustness when compared to the Cox proportional hazards estimating equation. Sean Devlin Statistical Models http://www.bepress.com/uwbiostat/paper354 http://www.bepress.com/uwbiostat/paper354 Tue, 02 Feb 2010 12:22:03 PST In group sequential clinical trials, it is necessary to estimate the amount of information present at interim analysis times relative to the amount of information that would be present at the final analysis. If only one measurement is made per individual, this is often the ratio of sample sizes available at the interim and final analyses. However, as discussed by Wu and Lan (1992), when the statistic of interest is a change over time, as with longitudinal data, such an approach overstates the information. In this paper, we discuss other problems that can result in overestimating the information, such as heteroscedasticity and correlated observations. We demonstrate that when using an inefficient estimator on unbalanced data, the true information growth can be nonmonotonic across interim analyses. Abigail B. Shoben Clinical Trials http://www.bepress.com/jhsem/vol7/iss1/7 http://www.bepress.com/jhsem/vol7/iss1/7 Tue, 02 Feb 2010 12:12:33 PST Thomas E. Poulin Homeland Security http://www.bepress.com/jhsem/vol7/iss1/6 http://www.bepress.com/jhsem/vol7/iss1/6 Tue, 02 Feb 2010 10:09:22 PST This article utilizes the State of Colorado as a case study in how individual states are adapting and applying federal capabilities-based planning models to their homeland security programs. The article reviews the corrective change in direction taken by Colorado in implementation of homeland security organizational strategies, structures, policies and procedures. The authors' findings lead to conclusions about Colorado's beginning phase of transforming deficient homeland security strategy, incoherent organization, and fragmented planning processes into sound strategy, focused structure, and organized methods. In November 2008, the Center for Homeland Security (CHS) at the University of Colorado at Colorado Springs began a research and mutual support effort with the Colorado Governor's Office of Homeland Security for the purpose of immersing in the state's revitalized homeland security planning cycle. The intent was to gain insight into the state's creation of a new homeland security organization, the application of a new homeland security strategy, and the efficacy of implementing federal capabilities-based planning processes from a strategic and operational perspective, rather than a federal grant application focus. Colorado's shift to a capabilities-based planning process was largely in response to criticism from both the Department of Homeland Security and Colorado state auditors on the use of federal homeland security funds. Audits described the state's strategy as disorganized and its homeland security structure as fractured with poor accountability and little meaningful oversight. This article examines the initial findings of the CHS immersion experience. Kurt A. Johnson Homeland Security http://www.bepress.com/jhsem/vol7/iss1/5 http://www.bepress.com/jhsem/vol7/iss1/5 Tue, 02 Feb 2010 07:31:31 PST David Munro Homeland Security