476 research outputs found

    Anatomy of a Community-Level Fiscal Impact Model: FIT-4-NH.

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    Abstract: This paper describes the development of a fiscal impact tool for New Hampshire communities (HT -4-NH). FIT -4-NH belongs to a family of computergenerated fiscal impact assessment models designed to estimate the impacts to local government revenues and expenditures that result from economic changes. In the past, work in this area has centered on the completion of countylevel models for the midwestern states. FIT-4-NH is unique in that it was designed for rural community-level use in the northern New England region of the country

    A Timed IO monad

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    Programming with explicit timing information is often tedious and error prone. This is especially visible in music programming where, when played, the specified durations of notes and rests must be shortened in order to compensate the actual duration of all surrounding processing. In this paper, we develop the notion of timed extension of a monad that aims at relieving programmers from such a burden. We show how, under simple conditions, such extensions can be built, and how useful features of monad programming such as asynchronous concurrency with promises or data-flow programming with monadic streams can be uniformly lifted to the resulting timed programming framework. Even though presented and developed in the abstract, the notion of timed extension of a monad is nevertheless illustrated by two concrete instances: a default timed IO monad where programmers specify durations in mi-croseconds, and a musically timed IO monad, where programmers specify durations in number of beats, the underlying tempo, that is, the speed of the music in beats per minute, possibly changed whenever needed

    Improvement of the Embarrassingly Parallel Search for Data Centers

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    International audienceWe propose an adaptation of the Embarrassingly Parallel Search (EPS) method for data centers. EPS is a simple but efficient method for parallel solving of CSPs. EPS decomposes the problem in many distinct subproblems which are then solved independently by workers. EPS performed well on multi-cores machines (40), but some issues arise when using more cores in a datacenter. Here, we identify the decomposition as the cause of the degradation and propose a parallel decomposition to address this issue. Thanks to it, EPS gives almost linear speedup and outperforms work stealing by orders of magnitude using the Gecode solver

    Book Reviews

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    Current Legal Problems 1956 Edited by G. W. Keeton and G. Schwarzenberger London: Stevens & Sons, 1956. Pp. vii, 275. 5.55reviewer:DavidF.Maxwell===================================SomeProblemsofProofundertheAnglo−AmericanSystemofLitigationByEdmundMorrisMorgan.NewYork:ColumbiaUniversityPress,1956.Pp.xii,195.5.55 reviewer: David F. Maxwell =================================== Some Problems of Proof under the Anglo-American System of Litigation By Edmund Morris Morgan. New York: Columbia University Press, 1956. Pp. xii, 195. 3.50 reviewer: Charles T. McCormick =================================== Effective Drafting of Leases with Check List and Forms By Milton N. Lieberman Newark: Gann Law Books, 1956. Pp. viii, 974 reviewer: Robert N. Cooks =================================== The Law and One Man Among Many By Arthur E. Sutherland Madison: University of Wisconsin Press, 1956. Pp. ix, 101. 2.50reviewer:KennethB.Hughs===================================ProxyContestsforCorporateControlByEdwardRossAranowandHerbertA.Einhorn.NewYork:ColumbiaUniversityPress,1957.Pp.xxiii,577.2.50 reviewer: Kenneth B. Hughs =================================== Proxy Contests for Corporate Control By Edward Ross Aranow and Herbert A. Einhorn. New York: Columbia University Press,1957. Pp. xxiii, 577. 15.00 reviewer: Jess Halstead =================================== Gibson\u27s Suits in Chancery By Arthur Crownover, Jr. Charlottesville: The Michie Company, 1955-1956. Vol. I, Pp. xxiii, 909; Vol. II,Pp. xv, 949. 45.00.reviewer:WalterP.Armstrong,Jr.===================================LaissezFaireandtheGeneral−WelfareState:AStudyofConflictinAmericanThought,1865−1901.BySidneyFineAnnArbor:UniversityofMichiganPress,1956.Pp.x,468.45.00. reviewer: Walter P. Armstrong, Jr. =================================== Laissez Faire and the General-Welfare State: A Study of Conflict in American Thought, 1865-1901. By Sidney Fine Ann Arbor: University of Michigan Press, 1956. Pp. x, 468. 7.50. reviewer: Howard Jay Graha

    The impact of the demographic transition on dengue in Thailand: Insights from a statistical analysis and mathematical modeling

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    Background: An increase in the average age of dengue hemorrhagic fever (DHF) cases has been reported in Thailand. The cause of this increase is not known. Possible explanations include a reduction in transmission due to declining mosquito populations, declining contact between human and mosquito, and changes in reporting. We propose that a demographic shift toward lower birth and death rates has reduced dengue transmission and lengthened the interval between large epidemics. Methods and Findings: Using data from each of the 72 provinces of Thailand, we looked for associations between force of infection (a measure of hazard, defined as the rate per capita at which susceptible individuals become infected) and demographic and climactic variables. We estimated the force of infection from the age distribution of cases from 1985 to 2005. We find that the force of infection has declined by 2% each year since a peak in the late 1970s and early 1980s. Contrary to recent findings suggesting that the incidence of DHF has increased in Thailand, we find a small but statistically significant decline in DHF incidence since 1985 in a majority of provinces. The strongest predictor of the change in force of infection and the mean force of infection is the median age of the population. Using mathematical simulations of dengue transmission we show that a reduced birth rate and a shift in the population's age structure can explain the shift in the age distribution of cases, reduction of the force of infection, and increase in the periodicity of multiannual oscillations of DHF incidence in the absence of other changes. Conclusions: Lower birth and death rates decrease the flow of susceptible individuals into the population and increase the longevity of immune individuals. The increase in the proportion of the population that is immune increases the likelihood that an infectious mosquito will feed on an immune individual, reducing the force of infection. Though the force of infection has decreased by half, we find that the critical vaccination fraction has not changed significantly, declining from an average of 85% to 80%. Clinical guidelines should consider the impact of continued increases in the age of dengue cases in Thailand. Countries in the region lagging behind Thailand in the demographic transition may experience the same increase as their population ages. The impact of demographic changes on the force of infection has been hypothesized for other diseases, but, to our knowledge, this is the first observation of this phenomenon

    Viral and Epidemiological Determinants of the Invasion Dynamics of Novel Dengue Genotypes

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    Dengue fever and the more severe dengue haemorrhagic fever and dengue shock syndrome are mosquito borne viral infections that have seen a major increase in terms of global distribution and total case numbers over the last few decades. There are currently four antigenically distinct and potentially co-circulating dengue serotypes and each serotype shows substantial genetic diversity, organised into phylogenetically distinct genotypes or lineages. While there is some evidence for positive selection, the evolutionary dynamics of dengue virus (DENV) is supposed to be mostly dominated by purifying selection due to the constraints imposed by its two-host life-cycle. Motivated by a recent genotype replacement event whereby the resident American/Asian lineage of dengue virus serotype 2 (DENV2) had been displaced by the fitter Asian-1 lineage we investigated some of the epidemiological factors that might determine the success and invasion dynamics of a novel, advantageous dengue genotype. Our results show that although small differences in viral fitness can explain the rapid expansion and fixation of novel genotypes, their fate is ultimately determined by the epidemiological landscape in which they arise

    Dengue vaccines: what we know, what has been done, but what does the future hold?

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    Dengue, a disease caused by any of the four serotypes of dengue viruses, is the most important arthropod-borne viral disease in the world in terms of both morbidity and mortality. The infection by these viruses induces a plethora of clinical manifestations ranging from asymptomatic infections to severe diseases with involvement of several organs. Severe forms of the disease are more frequent in secondary infections by distinct serotypes and, consequently, a dengue vaccine must be tetravalent. Although several approaches have been used on the vaccine development, no vaccine is available against these viruses, especially because of problems on the development of a tetravalent vaccine. Here, we describe briefly the vaccine candidates available and their ability to elicit a protective immune response. We also discuss the problems and possibilities of any of the vaccines in final development stage reaching the market for human use

    From Re-Emergence to Hyperendemicity: The Natural History of the Dengue Epidemic in Brazil

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    The spread of dengue virus is a major public health problem. Though the burden of dengue has historically been concentrated in Southeast Asian countries, Brazil has become the country that reports the largest number of cases in the world. While prior to 2007 the disease affected mostly adults, during the 2007 epidemic the number of dengue hemorrhagic fever cases more than doubled, and over 53% of cases were in children under 15 years of age. In this paper, we propose that the conditions for the shift were being set gradually since the re-introduction of dengue in 1986 and that they represent the transition from re-emergence to hyperendemicity. Using data from an age stratified seroprevalence study conducted in Recife, we estimated the force of infection (a measure of transmission intensity) between 1986–2006 and used these estimates to simulate the accumulation of immunity since the re-emergence. As the length of time that dengue has circulated increases, adults have a lower probability of remaining susceptible to primary or secondary infection and thus, cases become on average younger. If in fact the shift represents the transition from re-emergence to hyperendemicity, similar shifts are likely to be observed in the rest of Brazil, the American continent and other regions where transmission emerges

    No more, no less - A formal model for serverless computing

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    Serverless computing, also known as Functions-as-a-Service, is a recent paradigm aimed at simplifying the programming of cloud applications. The idea is that developers design applications in terms of functions, which are then deployed on a cloud infrastructure. The infrastructure takes care of executing the functions whenever requested by remote clients, dealing automatically with distribution and scaling with respect to inbound traffic. While vendors already support a variety of programming languages for serverless computing (e.g. Go, Java, Javascript, Python), as far as we know there is no reference model yet to formally reason on this paradigm. In this paper, we propose the first formal programming model for serverless computing, which combines ideas from both the λ\lambda-calculus (for functions) and the π\pi-calculus (for communication). To illustrate our proposal, we model a real-world serverless system. Thanks to our model, we are also able to capture and pinpoint the limitations of current vendor technologies, proposing possible amendments
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