ABD e-News Special Edition - May 18, 2007

Weekly newsletter

Report on a special investigation of Three Rivers Independent Living Corporation for the period July 1, 2005 through May 26, 2006

Report on a special investigation of Three Rivers Independent Living Corporation for the period July 1, 2005 through May 26, 2006

Special investigation of the Dallas County Mental Health Advocate for the period September 1, 2005 through March 31, 2006

Special investigation of the Dallas County Mental Health Advocate for the period September 1, 2005 through March 31, 2006

Are rules-based government programs shielded from special-interest politics? Evidence from revenue-sharing transfers in Brazil

Manipulation of government finances for the benefit of narrowly defined groups is usuallythought to be limited to the part of the budget over which politicians exercise discretion inthe short run, such as earmarks. Analyzing a revenue-sharing program between the centraland local governments in Brazil that uses an allocation formula based on local population estimates,I document two main results: first, that the population estimates entering the formulawere manipulated and second, that this manipulation was political in nature. Consistent withswing-voter targeting by the right-wing central government, I find that municipalities withroughly equal right-wing and non-right-wing vote shares benefited relative to opposition orconservative core support municipalities. These findings suggest that the exclusive focus ondiscretionary transfers in the extant empirical literature on special-interest politics may understatethe true scope of tactical redistribution that is going on under programmatic disguise.

Special investigation of the City of Riverdale for the period July 1, 2002 through June 30, 2005

Special investigation of the City of Riverdale for the period July 1, 2002 through June 30, 2005

ABD e-News - Special Edition, July 11, 2007

weekly newsletter

Special investigation of the City of Mystic for the period January 1, 2006 through January 31, 2007

Special investigation of the City of Mystic for the period January 1, 2006 through January 31, 2007

Beyond Smith's rule: An optimal dynamic index, rule for single machine stochastic scheduling with convex holding costs

Most research on single machine scheduling has assumedthe linearity of job holding costs, which is arguablynot appropriate in some applications. This motivates ourstudy of a model for scheduling $n$ classes of stochasticjobs on a single machine, with the objective of minimizingthe total expected holding cost (discounted or undiscounted). We allow general holding cost rates that are separable,nondecreasing and convex on the number of jobs in eachclass. We formulate the problem as a linear program overa certain greedoid polytope, and establish that it issolved optimally by a dynamic (priority) index rule,whichextends the classical Smith's rule (1956) for the linearcase. Unlike Smith's indices, defined for each class, ournew indices are defined for each extended class, consistingof a class and a number of jobs in that class, and yieldan optimal dynamic index rule: work at each time on a jobwhose current extended class has larger index. We furthershow that the indices possess a decomposition property,as they are computed separately for each class, andinterpret them in economic terms as marginal expected cost rate reductions per unit of expected processing time.We establish the results by deploying a methodology recentlyintroduced by us [J. Niño-Mora (1999). "Restless bandits,partial conservation laws, and indexability. "Forthcomingin Advances in Applied Probability Vol. 33 No. 1, 2001],based on the satisfaction by performance measures of partialconservation laws (PCL) (which extend the generalizedconservation laws of Bertsimas and Niño-Mora (1996)):PCL provide a polyhedral framework for establishing theoptimality of index policies with special structure inscheduling problems under admissible objectives, which weapply to the model of concern.

Audit report on a special investigation of the City of Gravity for the period January 1, 2003 through February 15, 2007

Audit report on a special investigation of the City of Gravity for the period January 1, 2003 through February 15, 2007

Special investigation of the Haverhill Volunteer Fire Department for the period January 1, 2003 through January 29, 2007

Special investigation of the Haverhill Volunteer Fire Department for the period January 1, 2003 through January 29, 2007

Impact of biocontrol strain Pseudomonas fluorescens CHA0 on rhizosphere bacteria isolated from barley (Hordeum vulgare L.) with special reference to Cytophaga-like bacteria.

AIMS: To assess the impact of the biocontrol strain Pseudomonas fluorescens CHA0 on a collection of barley rhizosphere bacteria using an agar plate inhibition assay and a plant microcosm, focusing on a CHA0-sensitive member of the Cytophaga-like bacteria (CLB). METHODS AND RESULTS: The effect of strain CHA0 on a collection of barley rhizosphere bacteria, in particular CLB and fluorescent pseudomonads sampled during a growth season, was assessed by a growth inhibition assay. On average, 85% of the bacteria were sensitive in the May sample, while the effect was reduced to around 68% in the July and August samples. In the May sample, around 95% of the CLB and around 45% of the fluorescent pseudomonads were sensitive to strain CHA0. The proportion of CHA0-sensitive CLB and fluorescent pseudomonad isolates decreased during the plant growth season, i.e. in the July and August samples. A particularly sensitive CLB isolate, CLB23, was selected, exposed to strain CHA0 (wild type) and its genetically modified derivatives in the rhizosphere of barley grown in gnotobiotic soil microcosms. Two dry-stress periods were imposed during the experiment. Derivatives of strain CHA0 included antibiotic or exopolysaccharide (EPS) overproducing strains and a dry-stress-sensitive mutant. Despite their inhibitory activity against CLB23 in vitro, neither wild-type strain CHA0, nor any of its derivatives, had a major effect on culturable and total cell numbers of CLB23 during the 23-day microcosm experiment. Populations of all inoculants declined during the two dry-stress periods, with soil water contents below 5% and plants reaching the wilting point, but they recovered after re-wetting the soil. Survival of the dry-stress-sensitive mutant of CHA0 was most affected by the dry periods; however, this did not result in an increased population density of CLB23. CONCLUSIONS: CLB comprise a large fraction of barley rhizosphere bacteria that are sensitive to the biocontrol pseudomonad CHA0 in vitro. However, in plant microcosm experiments with varying soil humidity conditions, CHA0 or its derivatives had no major impact on the survival of the highly sensitive CLB strain, CLB23, during two dry-stress periods and a re-wetting period; all co-existed well in the rhizosphere of barley plants. SIGNIFICANCE AND IMPACT OF THE STUDY: Results indicate a lack of interaction between the biocontrol pseudomonad CHA0 and a sensitive CLB when the complexity increases from agar plate assays to plant microcosm experiments. This suggests the occurrence of low levels of antibiotic production and/or that the two bacterial genera occupy different niches in the rhizosphere.

Report on a special investigation of the City of Clearfield for the period August 1, 2006 through June 30, 2007

Report on a special investigation of the City of Clearfield for the period August 1, 2006 through June 30, 2007

Report on a special investigation of the Fifth and Eighth Judicial Districts Department of Correctional Services (Districts) for the period January 1, 2003 through June 30, 2006

Report on a special investigation of the Fifth and Eighth Judicial Districts Department of Correctional Services (Districts) for the period January 1, 2003 through June 30, 2006

Parallel scheduling of multiclass M/M/m queues: Approximate and heavy-traffic optimization of achievable performance

We address the problem of scheduling a multiclass $M/M/m$ queue with Bernoulli feedback on $m$ parallel servers to minimize time-average linear holding costs. We analyze the performance of a heuristic priority-index rule, which extends Klimov's optimal solution to the single-server case: servers select preemptively customers with larger Klimov indices. We present closed-form suboptimality bounds (approximate optimality) for Klimov's rule, which imply that its suboptimality gap is uniformly bounded above with respect to (i) external arrival rates, as long as they stay within system capacity;and (ii) the number of servers. It follows that its relativesuboptimality gap vanishes in a heavy-traffic limit, as external arrival rates approach system capacity (heavy-traffic optimality). We obtain simpler expressions for the special no-feedback case, where the heuristic reduces to the classical $c \mu$ rule. Our analysis is based on comparing the expected cost of Klimov's ruleto the value of a strong linear programming (LP) relaxation of the system's region of achievable performance of mean queue lengths. In order to obtain this relaxation, we derive and exploit a new set ofwork decomposition laws for the parallel-server system. We further report on the results of a computational study on the quality of the $c \mu$ rule for parallel scheduling.

Special investigation of the Monona County Engineer’s Office for the period January 1, 2004 through April 20, 2007

Special investigation of the Monona County Engineer’s Office for the period January 1, 2004 through April 20, 2007