15,608 research outputs found
Estimating the Size and Growth of Unrecorded Economic Activity in Transition Countries: A Re-evaluation of Electric Consumption Method Estimates and their Implications
It is widely acknowledged that underground (unrecorded) economic activities play a major role in transition economies. Evaluations of the success and failure of the transition experience should therefore be based on total economic activity [TEA], namely, the sum of recorded and unrecorded economic activity. Substantive conclusions concerning the effects of unrecorded activities on the transition process as well as investigations of the causes and consequences of unrecorded activities have to date, relied extensively on estimates of unrecorded income based on variants of the electric consumption method [ECM] during the first half of the transition process. We first attempt to replicate these estimates employing improved data series. We then go on to extend and update alternative versions of the ECM estimates of unrecorded income for twenty five transition countries for the period 1989-2001. These new estimates enable us to examine the sensitivity of the results to alternative specifying assumptions, particularly, initial conditions. We find that our updated ECM estimates of the size of the unrecorded sector are not only highly sensitive to initial conditions, but they produce negative estimates of unrecorded income for many transition countries. Our findings are also compared to the new national accounting procedures that attempt to estimate exhaustive measures of the “non-observed economy”. Our disturbing results call into question many of the substantive conclusions reached by other scholars who relied on earlier ECM estimates to draw inferences about the transition process as well as the causes and consequences of underground economies in transition. In short, while we conclude that ECM estimates of the size of the unrecorded economy are unreliable, it is still possible to use the growth rate of the unrecorded sector to make important inferences about the transition process by examining the dynamic relationship between recorded and unrecorded sectors. The extension of our data base to cover the entire transition period will hopefully result in new investigations employing panel data rather than the more traditional method of applying simple cross country test procedures. Key words: underground, unreported, unrecorded, unobserved, hidden, informal, nonobserved, shadow economy, transition economies.http://deepblue.lib.umich.edu/bitstream/2027.42/40022/2/wp636.pd
Measuring Underground (Unobserved, Non-Observed, Unrecorded) Economies in Transition Countries: Can We Trust GDP?
This paper compiles alternative estimates of underground economies in twenty five transition countries during the transition decade and finds a disturbing lack of convergence between them, calling into question the reliability of GDP figures (which in varying degrees now include non-transparent imputations for the ìnonobserved economyî) as well as the macro model estimates of the unrecorded economy.http://deepblue.lib.umich.edu/bitstream/2027.42/64384/1/wp913.pd
Measuring Underground (Unobserved, Non-Observed, Unrecorded) Economies in Transition Countries: Can We Trust GDP?
This paper compiles alternative estimates of underground economies in twenty five transition countries during the transition decade and finds a disturbing lack of convergence between them, calling into question the reliability of GDP figures (which in varying degrees now include non-transparent imputations for the “nonobserved economy”) as well as the macro model estimates of the unrecorded economy.Underground, unrecorded, unobserved, non-observed, NOE, hidden, informal, shadow, GDP, national accounts, transition economies.
Contributions of Microgravity Test Results to the Design of Spacecraft Fire Safety Systems
Experiments conducted in spacecraft and drop towers show that thin-sheet materials have reduced flammability ranges and flame-spread rates under quiescent low-gravity environments (microgravity) as compared to normal gravity. Furthermore, low-gravity flames may be suppressed more easily by atmospheric dilution or decreasing atmospheric total pressure than their normal-gravity counterparts. The addition of a ventilating air flow to the low-gravity flame zone, however, can greatly enhance the flammability range and flame spread. These results, along with observations of flame and smoke characteristics useful for microgravity fire-detection 'signatures', promise to be of considerable value to spacecraft fire-safety designs. The paper summarizes the fire detection and suppression techniques proposed for the Space Station Freedom and discusses both the application of low-gravity combustion knowledge to improve fire protection and the critical needs for further research
Estimating the Size and Growth of Unrecorded Economic Activity in Transition Countries: A Re-evaluation of Electric Consumption Method Estimates and their Implications
It is widely acknowledged that underground (unrecorded) economic activities play a major role in transition economies. Evaluations of the success and failure of the transition experience should therefore be based on total economic activity [TEA], namely, the sum of recorded and unrecorded economic activity. Substantive conclusions concerning the effects of unrecorded activities on the transition process as well as investigations of the causes and consequences of unrecorded activities have to date, relied extensively on estimates of unrecorded income based on variants of the electric consumption method [ECM] during the first half of the transition process. We first attempt to replicate these estimates employing improved data series. We then go on to extend and update alternative versions of the ECM estimates of unrecorded income for twenty five transition countries for the period 1989-2001. These new estimates enable us to examine the sensitivity of the results to alternative specifying assumptions, particularly, initial conditions. We find that our updated ECM estimates of the size of the unrecorded sector are not only highly sensitive to initial conditions, but they produce negative estimates of unrecorded income for many transition countries. Our findings are also compared to the new national accounting procedures that attempt to estimate exhaustive measures of the “non-observed economy”. Our disturbing results call into question many of the substantive conclusions reached by other scholars who relied on earlier ECM estimates to draw inferences about the transition process as well as the causes and consequences of underground economies in transition. In short, while we conclude that ECM estimates of the size of the unrecorded economy are unreliable, it is still possible to use the growth rate of the unrecorded sector to make important inferences about the transition process by examining the dynamic relationship between recorded and unrecorded sectors. The extension of our data base to cover the entire transition period will hopefully result in new investigations employing panel data rather than the more traditional method of applying simple cross country test procedures.underground, unreported, unrecorded, unobserved, hidden, informal, shadow economy, transition economies, electric consumption method
Measuring Underground (Unobserved, Non-Observed, Unrecorded) Economies in Transition Countries: Can We Trust GDP?
Abstract This paper compiles alternative estimates of underground economies in twenty five transition countries during the transition decade and finds a disturbing lack of convergence between them, calling into question the reliability of GDP figures (which in varying degrees now include non-transparent imputations for the “non-observed economy”) as well as the macro model estimates of the unrecorded economy. A corollary of this finding is that substantive results from many studies examining the consequences of the radical transition from planned to market economies must be viewed with considerable skepticism. Underground (unobserved, non-observed, unrecorded) economic activities play a major role in transition economies. Evaluations of the success and failure of the transition experience should be based on estimates of total economic activity (TEA) namely, recorded plus unrecorded economic activity. We examine the conceptual and empirical relationships between new National Income and Product Accounts (NIPA) methods for obtaining “exhaustive” measures of total economic activity and the two most popular macro-model approaches (electric consumption and currency ratio models) for estimating the size and growth of the unrecorded sector. Our updated empirical results detailing the size and trajectory of unrecorded activities obtained from different estimation methods reveal a disturbing lack of convergence. Until these important differences are resolved, investigations of the relationship between economic reforms and economic outcomes during the transition decade must be viewed with considerable caution. Given the shortcomings of conventional macro model estimates of the underground economy and the lack of transparency and consistency of NOE estimates, it is high time that the profession acknowledges how little we really know about underground economies and their causes and consequences.Key words: Underground, unrecorded, unobserved, non-observed, NOE, hidden, informal, shadow, GDP, national accounts, transition economies
The ecodist Package for Dissimilarity-based Analysis of Ecological Data
Ecologists are concerned with the relationships between species composition and environmental framework incorporating space explicitly is an extremely flexible tool for answering these questions. The R package ecodist brings together methods for working with dissimilarities, including some not available in other R packages. We present some of the features of ecodist, particularly simple and partial Mantel tests, and make recommendations for their effective use. Although the partial Mantel test is often used to account for the effects of space, the assumption of linearity greatly reduces its effectiveness for complex spatial patterns. We introduce a modification of the Mantel correlogram designed to overcome this restriction and allow consideration of complex nonlinear structures. This extension of the method allows the use of partial multivariate correlograms and tests of relationship between variables at different spatial scales. Some of the possibilities are demonstrated using both artificial data and data from an ongoing study of plant community composition in grazinglands of the northeastern United States.
Burden of fetal alcohol syndrome in a rural West Coast area of South Africa
Background. Fetal alcohol syndrome (FAS) is common in parts of South Africa; rural residence is a frequently cited risk factor. We conducted a FAS school prevalence survey of an isolated rural community in a West Coast village of Western Cape Province, so obtaining the first directly measured rate, focusing specifically on a South African rural area, of FAS and partial FAS (PFAS).
Methods. The study area (Aurora village), a community of about 2 500 people in a grain-producing region, has one primary school. All learners were eligible for study inclusion. Initial anthropometry screening was followed by a diagnostic stage entailing examination by a dysmorphologist for features of FAS, neurodevelopmental assessment, and an interview assessing maternal alcohol consumption.
Results. Of 160 learners screened, 78 (49%) were screen-positive, of whom 63 (81%) were clinically assessed for FAS. The overall FAS/PFAS rate among the screened learners was 17.5% (95% confidence interval 12.0 - 24.2%), with 16 (10.0%) children having FAS and 12 (7.5%) PFAS. High rates of stunting, underweight and microcephaly were noted in all learners, especially those with FAS or PFAS. Five (18%) mothers of affected children were deceased by the time of assessment.
Conclusion. We describe very high rates of FAS/PFAS in an isolated rural part of the Western Cape that is not located in a viticultural region. Our study suggests that the prevalence of FA S may be very high in isolated communities, or in particular hot-spots. It adds to the growing evidence that FAS/PFAS is a significant, and underestimated, health problem in South Africa. Expanded screening and surveillance programmes, and preventive interventions, are urgently needed
Two-fluid model for a rotating trapped Fermi gas in the BCS phase
We investigate the dynamical properties of a superfluid gas of trapped
fermionic atoms in the BCS phase. As a simple example we consider the reaction
of the gas to a slow rotation of the trap. It is shown that the currents
generated by the rotation can be understood within a two-fluid model similar to
the one used in the theory of superconductors, but with a position dependent
ratio of normal and superfluid densities. The rather general result of this
paper is that already at very low temperatures, far below the critical one, an
important normal-fluid component appears in the outer regions of the gas. This
renders the experimental observation of superfluidity effects more difficult
and indicates that reliable theoretical predictions concerning other dynamical
properties, like the frequencies of collective modes, can only be made by
taking into account temperature effects.Comment: 6 pages, 4 figure
BEC-BCS Crossover and the Liquid-Gas Phase Transition in Hot and Dense Nuclear Matter
The effect of nucleon-nucleon correlations in symmetric nuclear matter at
finite temperature is studied beyond BCS theory. Starting from a Hartree-Fock
description of nuclear matter with the Gogny effective interaction, we add
correlations corresponding to the formation of preformed pairs and scattering
states above the superfluid critical temperature within the in-medium T-matrix
approach, which is analogous to the Nozieres-Schmitt-Rink theory. We calculate
the critical temperature for a BEC superfluid of deuterons, of a BCS superfluid
of nucleons, and in the crossover between these limits. The effect of the
correlations on thermodynamic properties (equation of state, energy, entropy)
and the liquid-gas phase transition is discussed. Our results show that
nucleon-nucleon correlations beyond BCS play an important role for the
properties of nuclear matter, especially in the low-density region.Comment: 11 pages, 12 figures; v2: minor modifications of the text, references
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