Global synchronization algorithms for the Intel iPSC/860

In a distributed memory multicomputer that has no global clock, global processor synchronization can only be achieved through software. Global synchronization algorithms are used in tridiagonal systems solvers, CFD codes, sequence comparison algorithms, and sorting algorithms. They are also useful for event simulation, debugging, and for solving mutual exclusion problems. For the Intel iPSC/860 in particular, global synchronization can be used to ensure the most effective use of the communication network for operations such as the shift, where each processor in a one-dimensional array or ring concurrently sends a message to its right (or left) neighbor. Three global synchronization algorithms are considered for the iPSC/860: the gysnc() primitive provided by Intel, the PICL primitive sync0(), and a new recursive doubling synchronization (RDS) algorithm. The performance of these algorithms is compared to the performance predicted by communication models of both the long and forced message protocols. Measurements of the cost of shift operations preceded by global synchronization show that the RDS algorithm always synchronizes the nodes more precisely and costs only slightly more than the other two algorithms

The Flow Approach to Labor Markets: New Data Sources and Micro-Macro Links

New data sources and products developed by the Bureau of Labor Statistics and the Bureau of the Census highlight the fluid character of U.S. labor markets. Private-sector job creation and destruction rates average nearly 8% of employment per quarter. Worker flows in the form of hires and separations are more than twice as large. The data also underscore the lumpy nature of micro-level employment adjustments. More than two-thirds of job destruction occurs at establishments that shrink by more than 10% within the quarter, and more than one-fifth occurs at those that shut down. Our study also uncovers highly nonlinear relationships of worker flows to employment growth and job flows at the micro level. These micro relations interact with movements over time in the cross-sectional density of establishment growth rates to produce recurring cyclical patterns in aggregate labor market flows. Cyclical movements in the layoffs-separation ratio, for example, and the propensity of separated workers to become unemployed reflect distinct micro relations for quits and layoffs. A dominant role for the job-finding rate in accounting for unemployment movements in mild downturns and a bigger role for the job-loss rate in severe downturns reflect distinct micro relations for hires and layoffs.

Policy uncertainty: a new indicator

The damaging impact of economic uncertainty on growth has been reasonably well studied - but what happens when there is uncertainty about economic policy-making? Nicholas Bloom and colleagues have developed a measure of this distinct kind of uncertainty, one that shows the value of restoring stability to current policy actions.US economic policy, global financial markets,

The Establishment-Level Behavior of Vacancies and Hiring

This paper is the first to study vacancies, hires, and vacancy yields at the establishment level in the Job Openings and Labor Turnover Survey, a large sample of U.S. employers. To interpret the data, we develop a simple model that identifies the flow of new vacancies and the job-filling rate for vacant positions. The fill rate moves counter to aggregate employment but rises steeply with employer growth rates in the cross section. It falls with employer size, rises with worker turnover rates, and varies by a factor of four across major industry groups. We also develop evidence that the employer-level hiring technology exhibits mild increasing returns in vacancies, and that employers rely heavily on other instruments, in addition to vacancies, as they vary hires. Building from our evidence and a generalized matching function, we construct a new index of recruiting intensity (per vacancy). Recruiting intensity partly explains the recent breakdown in the standard matching function, delivers a better-fitting empirical Beveridge Curve, and accounts for a large share of fluctuations in aggregate hires. Our evidence and analysis provide useful inputs for assessing, developing and calibrating theoretical models of search, matching and hiring in the labor market.

The establishment-level behavior of vacancies and hiring

The authors study vacancies, hires, and vacancy yields (success rate in generating hires) in the Job Openings and Labor Turnover Survey, a large representative sample of U.S. employers. The authors also develop a simple framework that identifies the monthly flow of new vacancies and the job-filling rate for vacant positions, the employer counterpart to the job-finding rate for unemployed workers. The job-filling rate moves counter to employment at the aggregate level but rises steeply with employer growth rates in the cross section. It falls with employer size, rises with the worker turnover rate, and varies by a factor of four across major industry groups. The authors' analysis also indicates that more than 1 in 6 hires occur without benefit of a vacancy, as defined by JOLTS. These findings provide useful inputs for assessing, developing, and calibrating theoretical models of search, matching, and hiring in the labor market.Employment ; Labor market

Recruiting Intensity during and after the Great Recession: National and Industry Evidence

We measure job-filling rates and recruiting intensity per vacancy at the national and industry levels from January 2001 to September 2011 using data from the Job Openings and Labor Turnover Survey. Construction makes up less than 5 percent of employment but accounts for more than 40 percent of the large swings in the job-filling rate during and after the Great Recession. Leisure & Hospitality accounts for nearly a quarter of the large drop in recruiting intensity during the Great Recession. We show that industry-level movements in job-filling rates and recruiting intensity are at odds with the implications of the standard matching function in labor search theory but consistent with a generalized function that incorporates an important role for recruiting intensity per vacancy.

Characterization of the Non-Uniqueness of Used Nuclear Fuel Burnup Signatures through a Mesh-Adaptive Direct Search

The use of passive gamma and neutron signatures from fission indicators is a common means of estimating used fuel burnup, enrichment, and cooling time. However, while characteristic fission product signatures such as 134Cs, 137Cs and 154Eu, and others are generally reliable estimators for used fuel burnup within the context where the assembly initial enrichment and the discharge time are known, in the absence of initial enrichment and/or cooling time information (such as when applying NDA measurements in a safeguards/verification context), these fission product indicators no longer yield a unique solution for assembly enrichment, burnup, and cooling time after discharge. Through the use of a new mesh-adaptive direct search (MADS) algorithm, it is possible to directly probe the shape of this ``degeneracy space\u27\u27 characteristic of individual nuclides (and combinations thereof), both as a function of constrained parameters (such as the assembly irradiation history) and unconstrained parameters (e.g., the cooling time before measurement and the measurement precision for particular indicator nuclides). In doing so, this affords the identification of potential means of narrowing the uncertainty space of potential assembly enrichment, burnup, and cooling time combinations, thereby bounding estimates of assembly plutonium content. In particular, combinations of gamma-emitting nuclides with distinct half-lives (e.g., 134Cs with 137Cs and 154Eu) in conjunction with gross neutron counting (via 244Cm) are able to reasonably constrain the degeneracy space of possible solutions to a space small enough to perform useful discrimination and verification of fuel assemblies based on their irradiation history

Dancing behavior of Cosmopterix victor Springer, a species new to the fauna of China (Lepidoptera: Cosmopterigidae).

Zum ersten Mal wird ein Fund der Bambus fressenden Art Cosmopterix victor Stringer, 1930 vom asiatischen Festland gemeldet. Weiterhin wird das sehr auffällige Tanzverhalten dieser Art beschrieben und abgebildet. Dabei handelt es sich um eine spezielle Anpassung, um für eine Ansammlung der adulten Schmetterlinge auf der Wirtspflanze zur Paarung und anschließenden Eiablage zu sorgen.Stichwörter Microlepidoptera, Zhejiang Province, Cosmopterigidae, Cosmopterix victor, dancing behavior.A bamboo-feeding species Cosmopterix victor Stringer, 1930 is mentioned from mainland Asia for the first time, with a description and illustration of its very striking dancing behavior. This behavior is regarded as a special adaptation providing the aggregation of adults on the host plants for mating and subsequent oviposition.Keywords Microlepidoptera, Zhejiang Province, Cosmopterigidae, Cosmopterix victor, dancing behavior

COMBINING TASTE PANELS WITH FOCUS GROUPS TO ELICIT CONSUMER PREFERENCES TOWARD A NEW SHRIMP PRODUCT

Consumer/Household Economics,