927 resultados para Direction of Arrival Estimator


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Data from the HEGRA air shower array are used to set an upper limit on the emission of gamma-radiation above 25 (18) TeV from the direction of the radio bright region DR4 within the SNR G78.2 + 2.1 of 2.5 (7.1). 10^-13 cm^-2 sec^-1. The shock front of SNR G78.2 + 2.1 probably recently overtook the molecular cloud Gong 8 which then acts as a target for the cosmic rays produced within the SNR, thus leading to the expectation of enhanced gamma-radiation. Using a model of Drury, Aharonian and Völk which assumes that SNRs are the sources of galactic cosmic rays via first order Fermi acceleration, we calculated a theoretical prediction for the gamma-ray flux from the DR4 region and compared it with our experimental flux limit. Our 'best estimate' value for the predicted flux lies a factor of about 18 above the upper limit for gamma-ray energies above 25 TeV. Possible reasons for this discrepancy are discussed.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The center of our Galaxy hosts a supermassive black hole, Sagittarius (Sgr) A∗. Young, massive stars within 0.5 pc of Sgr A∗ are evidence of an episode of intense star formation near the black hole a few million years ago, which might have left behind a young neutron star traveling deep into Sgr A∗’s gravitational potential. On 2013 April 25, a short X-ray burst was observed from the direction of the Galactic center. With a series of observations with the Chandra and the Swift satellites, we pinpoint the associated magnetar at an angular distance of 2.4±0.3 arcsec from Sgr A∗, and refine the source spin period and its derivative (P = 3.7635537(2) s and ˙ P = 6.61(4) × 10−12 s s−1), confirmed by quasi simultaneous radio observations performed with the Green Bank Telescope and Parkes Radio Telescope, which also constrain a dispersion measure of DM = 1750 ± 50 pc cm−3, the highest ever observed for a radio pulsar. We have found that this X-ray source is a young magnetar at ≈0.07–2 pc from Sgr A∗. Simulations of its possible motion around Sgr A∗ show that it is likely (∼90% probability) in a bound orbit around the black hole. The radiation front produced by the past activity from the magnetar passing through the molecular clouds surrounding the Galactic center region might be responsible for a large fraction of the light echoes observed in the Fe fluorescence features.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background: The immigrant population living in Spain grew exponentially in the early 2000s but has been particularly affected by the economic crisis. This study aims to analyse health inequalities between immigrants born in middle- or low-income countries and natives in Spain, in 2006 and 2012, taking into account gender, year of arrival and socioeconomic exposures. Methods: Study of trends using two cross-sections, the 2006 and 2012 editions of the Spanish National Health Survey, including residents in Spain aged 15–64 years (20 810 natives and 2950 immigrants in 2006, 14 291 natives and 2448 immigrants in 2012). Fair/poor self-rated health, poor mental health (GHQ-12 > 2), chronic activity limitation and use of psychotropic drugs were compared between natives and immigrants who arrived in Spain before 2006, adjusting robust Poisson regression models for age and socioeconomic variables to obtain prevalence ratios (PR) and 95% confidence interval (CI). Results: Inequalities in poor self-rated health between immigrants and natives tend to increase among women (age-adjusted PR2006 = 1.39; 95% CI: 1.24–1.56, PR2012 = 1.56; 95% CI: 1.33–1.82). Among men, there is a new onset of inequalities in poor mental health (PR2006 = 1.10; 95% CI: 0.86–1.40, PR2012 = 1.34; 95% CI: 1.06–1.69) and an equalization of the previously lower use of psychotropic drugs (PR2006 = 0.22; 95% CI: 0.11–0.43, PR2012 = 1.20; 95% CI: 0.73–2.01). Conclusions: Between 2006 and 2012, immigrants who arrived in Spain before 2006 appeared to worsen their health status when compared with natives. The loss of the healthy immigrant effect in the context of a worse impact of the economic crisis on immigrants appears as potential explanation. Employment, social protection and re-universalization of healthcare would prevent further deterioration of immigrants’ health status.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Both spin and orbital degrees of freedom contribute to the magnetic moment of isolated atoms. However, when inserted in crystals, atomic orbital moments are quenched because of the lack of rotational symmetry that protects them when isolated. Thus, the dominant contribution to the magnetization of magnetic materials comes from electronic spin. Here we show that nanoislands of quantum spin Hall insulators can host robust orbital edge magnetism whenever their highest occupied Kramers doublet is singly occupied, upgrading the spin edge current into a charge current. The resulting orbital magnetization scales linearly with size, outweighing the spin contribution for islands of a few nm in size. This linear scaling is specific of the Dirac edge states and very different from Schrodinger electrons in quantum rings. By modeling Bi(111) flakes, whose edge states have been recently observed, we show that orbital magnetization is robust with respect to disorder, thermal agitation, shape of the island, and crystallographic direction of the edges, reflecting its topological protection.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

prepared under the direction of Carroll D. Wright ; for the use of the United States Department of Labor.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This bill of lading is from Jasper Mauduit's shipment of books (his own gift and those bequeathed by Dr. Avery) to Andrew Oliver. The books were shipped from London to Boston via a ship called Hale Galley, under the direction of Captain Harris Hatch.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Includes minutes and other records, 1816-1829, of the trustees of the Society and other correspondence relating to the founding of the Society; treasurer's reports, 1843-1844, of J.G. Palfrey; lists of beneficiaries, 1824- 1830; and subscription receipts, 1819-1823. Also records regarding subscriptions for a professorship, 1828, an extract from the will of J.D. Williams, and legal matters. For more detailed information about records, see Harvard Archives LOCATION below.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: This map of the island of Jamaica; laid down from the papers and under the direction of Henry Moore, Esqr.; His Majesty's Lieutenant Governor and Commander in Chief of that island, in the years 1756, 57, 58, 59, 60 & 61; & from a great number of actual surveys performed by the publishers is humbly inscribed by his lordship's most obedient & most humble servants, Thos. Craskell, engineer, Jas. Simpson, surveyor. It was published by D. Fournier in 1763. Scale [ca 1:200,000]. This layer is image 1 of 4 total images of the four sheet map, representing the southwest portion of the map.The image inside the map neatline is georeferenced to the surface of the earth and fit to the Jamaica Grid projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as towns, villages, and other human settlements, roads, drainage, selected buildings, ground cover, shoreline features, and more. Relief shown pictorially. Includes also illustrations.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: This map of the island of Jamaica; laid down from the papers and under the direction of Henry Moore, Esqr.; His Majesty's Lieutenant Governor and Commander in Chief of that island, in the years 1756, 57, 58, 59, 60 & 61; & from a great number of actual surveys performed by the publishers is humbly inscribed by his lordship's most obedient & most humble servants, Thos. Craskell, engineer, Jas. Simpson, surveyor. It was published by D. Fournier in 1763. Scale [ca 1:200,000]. This layer is image 2 of 4 total images of the four sheet map, representing the southeast portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Jamaica Grid projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as towns, villages, and other human settlements, roads, drainage, selected buildings, ground cover, shoreline features, and more. Relief shown pictorially. Includes also illustrations.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: This map of the island of Jamaica; laid down from the papers and under the direction of Henry Moore, Esqr.; His Majesty's Lieutenant Governor and Commander in Chief of that island, in the years 1756, 57, 58, 59, 60 & 61; & from a great number of actual surveys performed by the publishers is humbly inscribed by his lordship's most obedient & most humble servants, Thos. Craskell, engineer, Jas. Simpson, surveyor. It was published by D. Fournier in 1763. Scale [ca 1:200,000]. This layer is image 3 of 4 total images of the four sheet map, representing the northeast portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Jamaica Grid projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as towns, villages, and other human settlements, roads, drainage, selected buildings, ground cover, shoreline features, and more. Relief shown pictorially. Includes also illustrations.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: This map of the island of Jamaica; laid down from the papers and under the direction of Henry Moore, Esqr.; His Majesty's Lieutenant Governor and Commander in Chief of that island, in the years 1756, 57, 58, 59, 60 & 61; & from a great number of actual surveys performed by the publishers is humbly inscribed by his lordship's most obedient & most humble servants, Thos. Craskell, engineer, Jas. Simpson, surveyor. It was published by D. Fournier in 1763. Scale [ca 1:200,000]. This layer is image 4 of 4 total images of the four sheet map, representing the northwest portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Jamaica Grid projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as towns, villages, and other human settlements, roads, drainage, selected buildings, ground cover, shoreline features, and more. Relief shown pictorially. Includes also illustrations.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: This map of the county of Cornwall, in the island of Jamaica; laid down from the papers, under the direction of, Henry Moore, Esqr., His Majesty's Lieutenant Governor, and Commander in Chief of that island, in the years 1756, 57, 58, 59, 60 & 61, & from a great number of actual surveys performed by the publishers is humbly inscribed by his lordship's most obedient & humble servants, Thos. Craskell, engineer, Jas. Simpson, surveyor. It was published by D. Fournier in 1763. Scale [ca. 1:95,000]. This layer is image 1 of 4 total images of the four sheet source map, representing the southwest portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Jamaica Grid projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as towns, villages, and other human settlements, roads, parish boundaries, drainage, selected buildings and names of landowners, ground cover, shoreline features, shoals, channels, anchorage points, and more.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: This map of the county of Cornwall, in the island of Jamaica; laid down from the papers, under the direction of, Henry Moore, Esqr., His Majesty's Lieutenant Governor, and Commander in Chief of that island, in the years 1756, 57, 58, 59, 60 & 61, & from a great number of actual surveys performed by the publishers is humbly inscribed by his lordship's most obedient & humble servants, Thos. Craskell, engineer, Jas. Simpson, surveyor. It was published by D. Fournier in 1763. Scale [ca. 1:95,000]. This layer is image 2 of 4 total images of the four sheet source map, representing the southeast portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Jamaica Grid projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as towns, villages, and other human settlements, roads, parish boundaries, drainage, selected buildings and names of landowners, ground cover, shoreline features, shoals, channels, anchorage points, and more.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: This map of the county of Cornwall, in the island of Jamaica; laid down from the papers, under the direction of, Henry Moore, Esqr., His Majesty's Lieutenant Governor, and Commander in Chief of that island, in the years 1756, 57, 58, 59, 60 & 61, & from a great number of actual surveys performed by the publishers is humbly inscribed by his lordship's most obedient & humble servants, Thos. Craskell, engineer, Jas. Simpson, surveyor. It was published by D. Fournier in 1763. Scale [ca. 1:95,000]. This layer is image 3 of 4 total images of the four sheet source map, representing the northeast portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Jamaica Grid projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as towns, villages, and other human settlements, roads, parish boundaries, drainage, selected buildings and names of landowners, ground cover, shoreline features, shoals, channels, anchorage points, and more.This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic paper map entitled: This map of the county of Cornwall, in the island of Jamaica; laid down from the papers, under the direction of, Henry Moore, Esqr., His Majesty's Lieutenant Governor, and Commander in Chief of that island, in the years 1756, 57, 58, 59, 60 & 61, & from a great number of actual surveys performed by the publishers is humbly inscribed by his lordship's most obedient & humble servants, Thos. Craskell, engineer, Jas. Simpson, surveyor. It was published by D. Fournier in 1763. Scale [ca. 1:95,000]. This layer is image 4 of 4 total images of the four sheet source map, representing the northwest portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Jamaica Grid projected coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as towns, villages, and other human settlements, roads, parish boundaries, drainage, selected buildings and names of landowners, ground cover, shoreline features, shoals, channels, anchorage points, and more. This layer is part of a selection of digitally scanned and georeferenced historic maps from the Harvard Map Collection. These maps typically portray both natural and manmade features. The selection represents a range of originators, ground condition dates, scales, and map purposes.