77 research outputs found
The Panther Mountain circular structure, a possible buried meteorite crater
Panther Mountain, located near Phoenicia, New York, is part of the Catskill Mountains, which form the eastern end of the Allegheny Plateau in New York. It is a circular mass defined physiographically by an anomalous circular drainage pattern produced by Esopus Creek and its tributary Woodland Creek. The circular valley that rings the mountain is fracture-controlled; where bedrock is exposed, it shows a joint density 5 to 10 times greater than that on either side of the valley. Where obscured by alluvial valley fill, the bedrock's low seismic velocity suggests that this anomalous fracturing is continuous in the bedrock underlying the rim valley. North-south and east-west gravity and magnetic profiles were made across the structure. Terrane-corrected, residual gravity profiles show an 18-mgal negative anomaly, and very steep gradients indicate a near-surface source. Several possible explanations of the gravity data were modeled. We conclude that the Panther Mountain circular structure is probably a buried meteorite crater that formed contemporaneously with marine or fluvial sedimentation during Silurian or Devonian time. An examination of drill core and cuttings in the region is underway to search for ejecta deposits and possible seismic and tsunami effects in the sedimentary section. Success would result in both dating the impact and furnishing a chronostratigraphic marker horizon
On the role of eddies and surface forcing in the heat transport and overturning circulation in marginal seas
Author Posting. © American Meteorological Society, 2011. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 24 (2011): 4844–4858, doi:10.1175/2011JCLI4130.1.The factors that determine the heat transport and overturning circulation in marginal seas subject to wind forcing and heat loss to the atmosphere are explored using a combination of a high-resolution ocean circulation model and a simple conceptual model. The study is motivated by the exchange between the subpolar North Atlantic Ocean and the Nordic Seas, a region that is of central importance to the oceanic thermohaline circulation. It is shown that mesoscale eddies formed in the marginal sea play a major role in determining the mean meridional heat transport and meridional overturning circulation across the sill. The balance between the oceanic eddy heat flux and atmospheric cooling, as characterized by a nondimensional number, is shown to be the primary factor in determining the properties of the exchange. Results from a series of eddy-resolving primitive equation model calculations for the meridional heat transport, overturning circulation, density of convective waters, and density of exported waters compare well with predictions from the conceptual model over a wide range of parameter space. Scaling and model results indicate that wind effects are small and the mean exchange is primarily buoyancy forced. These results imply that one must accurately resolve or parameterize eddy fluxes in order to properly represent the mean exchange between the North Atlantic and the Nordic Seas, and thus between the Nordic Seas and the atmosphere, in climate models.This study was supported by the
National Science Foundation under Grants OCE-0726339
and OCE-0850416
The Size and Growth of the Hidden Economy in Norway
The present size of the hidden economy in Norway is between 4 and 6 percent of GDP, of which
hidden labor income constitutes about half. A survey approach reveals that 415 of the population is
of the opinion that people in general accept income from moonlighting that is not reported, and 213
believes that this share of acceptance is on the increase. Furthermore, surveys clearly show that
hidden labor services are of satisfactory quality, that they mainly are paid for in cash, but with
checks being increasingly used, and that buyers find it easier to obtain services from the hidden labor
market than from the regular one. A shortening of the work week in order to alleviate unemployment
may result in an increased supply of hidden labor
Ar-Ar Analysis of Chelyabinsk: Evidence for a Recent Impact
The Chelyabinsk meteorite is an LL5 ordinary chondrite that fell as a spectacular fireball on February 15th, 2013, over the Ural region in Russia. The meteoroid exploded at an altitude of 25-30 km, producing shockwaves that broke windowpanes in Chelyabinsk and surrounding areas, injuring some 1500 people. Analyses of the samples show that the meteorite underwent moderate shock metamorphism (stage S4; 25-35 GPa) [1]. Most of the samples have a fusion crust ranging from ~0.1-1mm thick, and roughly a third of the samples were composed of a dark fine-grained impact melt with chondrule fragments which were targeted for chronometry. A Pb-Pb age obtained by [2] of a shock-darkened and potentially melted sample of Chelyabinsk is reported as 4538.3 +/- 2.1 Ma, while a U-Pb study [3] gave an upper concordia intercept of 4454 +/- 67 Ma and a lower intercept of 585 +/- 390. Galimov et al. 2013 [1] suggest the Sm-Nd system records a recent impact event [~290 Ma] that may represent separation from the parent body, while the Rb-Sr isotopic system is disturbed and does not give any definitive isochron. In order to better understand its history, we have performed 40Ar-39Ar analysis on multiple splits of two Chelyabinsk samples; clast- rich MB020f,2 and melt-rich MB020f,5. The term "clast-rich" lithology is meant to indicate a mechanical mixture of highly shock-darkened and less shocked components, both with some shock melt veining
Influences of precipitation on water mass transformation and deep convection
Author Posting. © American Meteorological Society, 2012. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 42 (2012): 1684–1700, doi:10.1175/JPO-D-11-0230.1.The influences of precipitation on water mass transformation and the strength of the meridional overturning circulation in marginal seas are studied using theoretical and idealized numerical models. Nondimensional equations are developed for the temperature and salinity anomalies of deep convective water masses, making explicit their dependence on both geometric parameters such as basin area, sill depth, and latitude, as well as on the strength of atmospheric forcing. In addition to the properties of the convective water, the theory also predicts the magnitude of precipitation required to shut down deep convection and switch the circulation into the haline mode. High-resolution numerical model calculations compare well with the theory for the properties of the convective water mass, the strength of the meridional overturning circulation, and also the shutdown of deep convection. However, the numerical model also shows that, for precipitation levels that exceed this critical threshold, the circulation retains downwelling and northward heat transport, even in the absence of deep convection.This study was supported by the
National Science Foundation underGrantsOCE-0850416,
OCE-0959381, andOCE-0859381.2013-04-0
Informal Employment
The myth surrounding negative connotation of informal employment / informal economy work engagement is one that needs to be revisited as research ventures must be pursued in the direction of encouraging those engaged in it to feel quite elated about their boldness in becoming actively involved in economic development activities. Equally, sensitive approaches should be pursued in pursuance of government statutory obligations in addressing core services like expenditures connected with education and health for example, which can only be achieved through revenue raised from genuine contributions made by the workforce, be it through formal or informal work engagement
The Use of Cash and the Size of the Shadow Economy in Sweden
We use an 'unexplained demand for cash' approach to measure the size of the shadow economy in Sweden. The size of the shadow economy is found to have increased from 3.8 to 6.5 per cent of GDP from 1990 to 2004. This result is also supported by our finding of an increased residual between households' recorded disposable income and their consumption, investments and changes in net financial positions. Moreover, the correlation between the demand for cash that cannot be explained by recorded transactions and this residual is strong
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