Investigating Mars: Candor Chasma

NASA Image and Video Library

2018-01-09

This image shows part of western Candor and the erosion of a large mesa. Layered materials are visible throughout the image. The dark material with the linear appearance in the middle of the image are sand dunes. Sand dunes are created by wind action. At the present time, wind is the active process shaping the surface. Candor Chasma is one of the largest canyons that make up Valles Marineris. It is approximately 810 km long (503 miles) and has is divided into two regions - eastern and western Candor. Candor is located south of Ophir Chasma and north of Melas Chasma. The border with Melas Chasma contains many large landslide deposits. The floor of Candor Chasma includes a variety of landforms, including layered deposits, dunes, landslide deposits and steep sided cliffs and mesas. Many forms of erosion have shaped Chandor Chasma. There is evidence of wind and water erosion, as well as significant gravity driven mass wasting (landslides). The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 6245 Latitude: -5.77639 Longitude: 284.339 Instrument: VIS Captured: 2003-05-12 14:49 https://photojournal.jpl.nasa.gov/catalog/PIA22161

Investigating Mars: Ius Chasma

NASA Image and Video Library

2018-02-28

This VIS image shows the eastern end of Ius Chasma. The southern canyon wall is at the bottom of the image, with dark sand and sand dunes. The presence of mobile sand indicates that winds are eroding, depositing and changing the canyon floor. The rest of the image is dominated by large landslide deposits. At the top of the image are two overlapping deposits from landslides originating on the northern chasma wall. The landslide deposit on the left side of the image originate from the southern chasma wall. A landslide is a failure of slope due to gravity. They initiate due to several reasons. A lower layer of poorly cemented/resistant material may have been eroded, undermining the wall above which then collapses; earthquake seismic waves can cause the slope to collapse; and even an impact event near the canyon wall can cause collapse. As millions of tons of material fall and slide down slope a scalloped cavity forms at the upper part where the slope failure occurred. At the material speeds downhill it will pick up more of the underlying slope, increasing the volume of material entrained into the landslide. Whereas some landslides spread across the canyon floor forming lobate deposits, very large volume slope failures will completely fill the canyon floor in a large complex region of chaotic blocks. Ius Chasma is at the western end of Valles Marineris, south of Tithonium Chasma. Valles Marineris is over 4000 kilometers long, wider than the United States. Ius Chasma is almost 850 kilometers long (528 miles), 120 kilometers wide and over 8 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified

Investigating Mars: Coprates Chasma

NASA Image and Video Library

2017-10-05

Coprates Chasma is one of the numerous canyons that make up Valles Marineris. The chasma stretches for 960 km (600 miles) from Melas Chasma to the west and Capri Chasma to the east. Landslide deposits, layered materials and sand dunes cover a large portion of the chasma floor. This image is located in eastern Coprates Chasma. The plateau above the chasma is visible in this image. The cliff face is very steep, with the elevation dropping over 3 miles from the plateau to the canyon floor. Craters are relatively rare on the chasma floor, the one in this image is fairly large. The crater rim has affected winds in this region, causing the interior dunes within the crater as well as the dunes outside the crater rim. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 37804 Latitude: -14.4843 Longitude: 302.193 Instrument: VIS Captured: 2010-06-23 01:14 https://photojournal.jpl.nasa.gov/catalog/PIA21999

Investigating Mars: Coprates Chasma

NASA Image and Video Library

2017-09-29

Coprates Chasma is one of the numerous canyons that make up Valles Marineris. The chasma stretches for 960 km (600 miles) from Melas Chasma to the west and Capri Chasma to the east. Landslide deposits, layered materials and sand dunes cover a large portion of the chasma floor. This image is located in central Coprates Chasma. The floor of the chasma is covered by a complex deposit of material. This chaotic surface differs from most of the floor of the canyon and indicate a local process, perhaps a very large landslide or failure of the cliff face. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 27086 Latitude: -13.564 Longitude: 300.618 Instrument: VIS Captured: 2008-01-22 12:04 https://photojournal.jpl.nasa.gov/catalog/PIA21994

Investigating Mars: Ius Chasma

NASA Image and Video Library

2018-02-23

Continuing eastward thru central Ius Chasma, this image shows a section of chasma that is not dominated by landslide deposits. Geryon Montes, in the upper half of the image, has several visible faults, including a pair of faults that divide the uppermost ridge into two sections. Between the montes and the southern wall face is a region of sand and sand dunes. The presence of mobile sand indicates that winds are eroding, depositing and changing the canyon floor. A landslide is a failure of slope due to gravity. They initiate due to several reasons. A lower layer of poorly cemented/resistant material may have been eroded, undermining the wall above which then collapses; earthquake seismic waves can cause the slope to collapse; and even an impact event near the canyon wall can cause collapse. As millions of tons of material fall and slide down slope a scalloped cavity forms at the upper part where the slope failure occurred. At the material speeds downhill it will pick up more of the underlying slope, increasing the volume of material entrained into the landslide. Whereas some landslides spread across the canyon floor forming lobate deposits, very large volume slope failures will completely fill the canyon floor in a large complex region of chaotic blocks. Ius Chasma is at the western end of Valles Marineris, south of Tithonium Chasma. Valles Marineris is over 4000 kilometers long, wider than the United States. Ius Chasma is almost 850 kilometers long (528 miles), 120 kilometers wide and over 8 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying

Investigating Mars: Coprates Chasma

NASA Image and Video Library

2017-10-06

Coprates Chasma is one of the numerous canyons that make up Valles Marineris. The chasma stretches for 960 km (600 miles) from Melas Chasma to the west and Capri Chasma to the east. Landslide deposits, layered materials and sand dunes cover a large portion of the chasma floor. This image is located in central Coprates Chasma. The brighter materials at the bottom of the image are layered deposits. It is unknown how deep these canyon deposits were when they formed. The layering is only visible due to erosion, making it difficult to estimate the original thickness. While layered deposits can be found on the floor of Coprates Chasma, they are most commonly found along the lower elevations and at the bottom of the cliff faces in the canyon. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 51810 Latitude: -12.6848 Longitude: 295.197 Instrument: VIS Captured: 2013-08-18 22:56 https://photojournal.jpl.nasa.gov/catalog/PIA22000

Investigating Mars: Coprates Chasma

NASA Image and Video Library

2017-09-27

Coprates Chasma is one of the numerous canyons that make up Valles Marineris. The chasma stretches for 960 km (600 miles) from Melas Chasma to the west and Capri Chasma to the east. Landslide deposits, layered materials and sand dunes cover a large portion of the chasma floor. This image is located in central Coprates Chasma. The image shows multiple landslide features, which form the bright lobed shaped deposits at the bottom of the canyon cliff face (top of image). The linear grooves on the top of the large landslide deposit were formed as the material came to rest on the canyon floor. The other features on the chasma floor are layered materials that have been weathered. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 16803 Latitude: -12.5614 Longitude: 296.887 Instrument: VIS Captured: 2005-09-27 20:25 https://photojournal.jpl.nasa.gov/catalog/PIA21992

Investigating Mars: Coprates Chasma

NASA Image and Video Library

2017-10-02

Coprates Chasma is one of the numerous canyons that make up Valles Marineris. The chasma stretches for 960 km (600 miles) from Melas Chasma to the west and Capri Chasma to the east. Landslide deposits, layered materials and sand dunes cover a large portion of the chasma floor. This image is located in eastern Coprates Chasma, just east of the previous image. In this image, the lobate margins of several landslide deposits are easy to identify. This indicates the chaotic surface in yesterday's image are materials emplaced by landslides. The brighter features at the bottom of the image are layered materials. There are also dunes in the region with the layered deposits. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 33037 Latitude: -13.8409 Longitude: 301.104 Instrument: VIS Captured: 2009-05-26 13:16 https://photojournal.jpl.nasa.gov/catalog/PIA21995

Investigating Mars: Ius Chasma

NASA Image and Video Library

2018-02-27

This VIS image shows part of the eastern end of Ius Chasma. Geryon Montes are located in the bottom half of the image. Between the montes and the southern wall face is a region of sand and sand dunes. The presence of mobile sand indicates that winds are eroding, depositing and changing the canyon floor. The top of the image is dominated by a large landslide deposit. The radial surface grooves are still visible, but the region as a whole as undergone significant erosion. A landslide is a failure of slope due to gravity. They initiate due to several reasons. A lower layer of poorly cemented/resistant material may have been eroded, undermining the wall above which then collapses; earthquake seismic waves can cause the slope to collapse; and even an impact event near the canyon wall can cause collapse. As millions of tons of material fall and slide down slope a scalloped cavity forms at the upper part where the slope failure occurred. At the material speeds downhill it will pick up more of the underlying slope, increasing the volume of material entrained into the landslide. Whereas some landslides spread across the canyon floor forming lobate deposits, very large volume slope failures will completely fill the canyon floor in a large complex region of chaotic blocks. Ius Chasma is at the western end of Valles Marineris, south of Tithonium Chasma. Valles Marineris is over 4000 kilometers long, wider than the United States. Ius Chasma is almost 850 kilometers long (528 miles), 120 kilometers wide and over 8 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and

Investigating Mars: Ius Chasma

NASA Image and Video Library

2018-02-26

This VIS image shows part of eastern Ius Chasma. The lower elevations of Geryon Montes are located at the top of the image. Between the montes and the southern wall face is a region of sand and sand dunes. The presence of mobile sand indicates that winds are eroding, depositing and changing the canyon floor. The texture of the canyon floor beneath the dunes and elsewhere in the image is an indication of water, in some form, was part of the process creating the surface. There is a tongue of material emerging from the canyon wall that has steep sides, this may be a delta formed by material washing down the valley and into a body of standing water, like a lake. It may also just be a landslide deposit that has undergone extensive weathering. A landslide is a failure of slope due to gravity. They initiate due to several reasons. A lower layer of poorly cemented/resistant material may have been eroded, undermining the wall above which then collapses; earthquake seismic waves can cause the slope to collapse; and even an impact event near the canyon wall can cause collapse. As millions of tons of material fall and slide down slope a scalloped cavity forms at the upper part where the slope failure occurred. At the material speeds downhill it will pick up more of the underlying slope, increasing the volume of material entrained into the landslide. Whereas some landslides spread across the canyon floor forming lobate deposits, very large volume slope failures will completely fill the canyon floor in a large complex region of chaotic blocks. Ius Chasma is at the western end of Valles Marineris, south of Tithonium Chasma. Valles Marineris is over 4000 kilometers long, wider than the United States. Ius Chasma is almost 850 kilometers long (528 miles), 120 kilometers wide and over 8 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive

Investigating Mars: Tithonium Chasma

NASA Image and Video Library

2018-02-07

This VIS image shows part of the floor of Tithonium Chasma. Eroded materials cover most of the image. The initial formation of layered floor deposits was possibly created of air fall of dust, sand, and volcanic materials and water lain materials. The weathering of these deposits is probably by the wind. The bottom part of the image has complex, hummocky material, probably very old landslide deposits. At the top of the image is a large mound of material that has been eroded mainly by wind action. The overlapping of these surfaces indicates a long history of modication of Tithonium Chasma. Tithonium Chasma is at the western end of Valles Marineris. Valles Marineris is over 4000 kilometers long, wider than the United States. Tithonium Chasma is almost 810 kilometers long (499 miles), 50 kilometers wide and over 6 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the

Tithonium Chasma/Ius Chasma

NASA Technical Reports Server (NTRS)

1998-01-01

Banded outcrops in walls of Tithonium Chasma/Ius Chasma section of Vallis Marineris. This 4.6 x 4.3 km image (frame 1303) is centered near 6.6 degrees south, 90.4 degrees west.

Figure caption from Science Magazine

Investigating Mars: Tithonium Chasma

NASA Image and Video Library

2018-02-06

This VIS image shows part of Tithonium Chasma. The ridge visible at the top of the image is not the top of the canyon. The top of the canyon is off the image to the north. A lobate "tongue" visible between the ridge and the top of the canyon is the deposit left by a landslide event. This material is more resistant and forms the ridges extending down the canyon walls. Eroded materials cover much of the canyon floor. The initial formation of layered floor desposits was possibly created of air fall of dust, sand, and volcanic materials and water lain materials. The weathering of these deposits is probably by the wind. Loose sand and dust can be seen in other portions of this image. Tithonium Chasma is at the western end of Valles Marineris. Valles Marineris is over 4000 kilometers long, wider than the United States. Tithonium Chasma is almost 810 kilometers long (499 miles), 50 kilometers wide and over 6 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels

Investigating Mars: Melas Chasma

NASA Image and Video Library

2017-12-07

Melas Chasma is part of the largest canyon system on Mars, Valles Marineris. At only 563 km long (349 miles) it is not the longest canyon, but it is the widest. Located in the center of Valles Marineris, it has depths up to 9 km below the surrounding plains, and is the location of many large landslide deposits, as will as layered materials and sand dunes. There is evidence of both water and wind action as modes of formation for many of the interior deposits. This VIS image is located along the northern cliff face of the chasma. The linear features are large landslide surfaces. A region of sand dunes is located along the change in elevation from the cliff face at the top of the image and the floor of the canyon at the bottom of the image. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 31790 Latitude: -10.3951 Longitude: 290.141 Instrument: VIS Captured: 2009-02-12 20:47 https://photojournal.jpl.nasa.gov/catalog/PIA22137

Dunes Streaming through Hills

NASA Image and Video Library

2014-02-26

This dramatic image observed by NASA Mars Reconnaissance Orbiter shows dark rippled bodies of sand, sometimes in the form of dunes, streaming through Ganges Chasma. The floor of the canyon is covered by hills and mesas.

Investigating Mars: Tithonium Chasma

NASA Image and Video Library

2018-02-05

This VIS image shows part of the central region of Tithonium Chasma. The steep wall of the canyon is visible at the top of the image. The top of the canyon walls are layered, mostly likely by numerous volcanic flows. This material is more resistant and forms the ridges extending down the canyon walls. A large landslide deposit covers the right side of the image. An eroded mound on the floor of the canyon exists at the bottom left of the image. The initial formation of the mound was possibly created of air fall of dust, sand, and volcanic materials and water lain materials. Tithonium Chasma is at the western end of Valles Marineris. Valles Marineris is over 4000 kilometers long, wider than the United States. Tithonium Chasma is almost 810 kilometers long (499 miles), 50 kilometers wide and over 6 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the

Investigating Mars: Melas Chasma

NASA Image and Video Library

2017-12-08

Melas Chasma is part of the largest canyon system on Mars, Valles Marineris. At only 563 km long (349 miles) it is not the longest canyon, but it is the widest. Located in the center of Valles Marineris, it has depths up to 9 km below the surrounding plains, and is the location of many large landslide deposits, as will as layered materials and sand dunes. There is evidence of both water and wind action as modes of formation for many of the interior deposits. This VIS image is located along the northern side of the chasma. The linear features are on the surface of a large landslide. This region of Melas Chasma is covered by several very large landslide deposits. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 36020 Latitude: -9.09641 Longitude: 288.172 Instrument: VIS Captured: 2010-01-27 03:51 https://photojournal.jpl.nasa.gov/catalog/PIA22138

Investigating Mars: Ius Chasma

NASA Image and Video Library

2018-03-02

Ius Chasma is unique from the other chasmata of Valles Marineris in possessing mega gullies on both sides of the chasma. The largest mega gullies are located in Sinai Planum, dissecting those plains and emptying into the canyon. These mega gullies are called Louros Valles. Mega gullies are thought to be sapping channels caused by groundwater flow and erosion. The Earth analog is springs - water that flows underground and then breaches the surface creating channels. The morphology of the Mars gullies mirrors terrestrial springs. The channel is fairly uniform in width and the "head" of the channel is rounded like an amphitheater. The channel lengthens by erosion at the "head" backwards as the surface where the spring emerges is undercut. For Mars it is theorized that subsurface water would stay liquid due to underground heating. The channels in this image are parts of the two largest mega gullies. Note how every channel head is the amphitheater bowl shape. Ius Chasma is at the western end of Valles Marineris, south of Tithonium Chasma. Valles Marineris is over 4000 kilometers long, wider than the United States. Ius Chasma is almost 850 kilometers long (528 miles), 120 kilometers wide and over 8 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. There are many features that indicate flowing and standing water played a part in the chasma formation. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS

Investigating Mars: Ius Chasma

NASA Image and Video Library

2018-03-01

Ius Chasma is unique from the other chasmata of Valles Marineris in possessing mega gullies on both sides of the chasma. The largest mega gullies are located in Sinai Planum, dissecting those plains and emptying into the canyon. These mega gullies are called Louros Valles. Mega gullies are thought to be sapping channels caused by groundwater flow and erosion. The Earth analog is springs - water that flows underground and then breaches the surface creating channels. The morphology of the Mars gullies mirrors terrestrial springs. The channel is fairly uniform in width and the "head" of the channel is rounded like an amphiteater. The channel lengthens by erosion at the "head" backwards as the surface where the spring emerges is undercut. For Mars it is theorized that subsurface water would stay liquid due to underground heating. The "X" in the lower half of the image and the channel at the very bottom are parts of the two largest mega gullies. Ius Chasma is at the western end of Valles Marineris, south of Tithonium Chasma. Valles Marineris is over 4000 kilometers long, wider than the United States. Ius Chasma is almost 850 kilometers long (528 miles), 120 kilometers wide and over 8 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. There are many features that indicate flowing and standing water played a part in the chasma formation. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR

Melas Chasma - False Color

NASA Image and Video Library

2015-10-08

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. These false color images may reveal subtle variations of the surface not easily identified in a single band image. Today's false color image shows part of the floor of Melas Chasma. The dark blue region in this false color image is sand dunes. Orbit Number: 12061 Latitude: -12.2215 Longitude: 289.105 Instrument: VIS Captured: 2004-09-02 10:11 http://photojournal.jpl.nasa.gov/catalog/PIA19793

Coprates Chasma

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 21 June 2002) The Science This image covers a portion of Coprates Chasma, located near 15.5S, 57.8W, which is part of the Valles Marineris system of canyons that stretch for thousands of kilometers. This image displays clearly the contrast between bedrock, sand, and dust surfaces. The steepest slopes, such as on the canyon walls, appear to be free of the mantle of dust and sand that is nearly ubiquitous elsewhere in the image. Layering is clearly present in the bedrock unit, but it is not clear if that layering is due to sedimentary deposits or volcanic lava flows. Superimposed on the slopes is a mantle of dust in a manner that appears similar to snow covered mountains on Earth. This is because in both situations, fine-grained dry, particulate material is settling on a sloped surface. Collecting in the valleys and, in some cases, climbing up the slopes are several sand sheets. The amount of cover and the apparent thickness of these sands give some indication to the huge volume of material that is collected here. The orientation of the slip faces of the dunes in this image can be used to deduce the prevalent wind patterns in the region. In this case, the prevalent wind direction is towards the east but there are areas where the winds indicate a more complex system, perhaps indicating topographic control of the local winds. The Story The canyon walls of Coprates, the old name for the Persian River Ab-I-Diz, descend clearly at the top of this image, without being obscured by the dust that covers much of this region. Coprates Chasma is part of Valles Marineris, the largest canyon system in the solar system. In addition to the hard bedrock and dust, sand dunes also appear on the floor of the canyon. They almost look as though they've been raked by a Zen gardener, but the eastward-blowing wind is really responsible for their rows. Scientists can tell the direction of the wind by looking at the slip faces of the dunes -- that is, by identifying the steep

Ganges Features

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Context image for PIA03285 Ganges Features

This image shows part of Ganges Chasma. Several landslides occur at the top of the image, while dunes and canyon floor deposits are visible at the bottom of the image.

Image information: VIS instrument. Latitude -6.8N, Longitude 312.2E. 17 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Ganges Landslide

NASA Technical Reports Server (NTRS)

2006-01-01

[figure removed for brevity, see original site] Context image for PIA03681 Ganges Landslide

Two large landslides dominate this image of part of Ganges Chasma. The eroded surface of an old landslide covers the north half of the image, while a more recent landslide occurs to the south.

Image information: VIS instrument. Latitude -6.7N, Longitude 310.4E. 17 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Investigating Mars: Tithonium Chasma

NASA Image and Video Library

2018-02-16

In this VIS image of Tithonium Chasma both sides of the chasma are visible. In this narrow and deep part of the chasma exist both large, chaotic block landslide deposits with smaller lobate shaped landslide deposits on top. Tithonium Chasma has numerous large landslide deposits. The resistant material of the plateau surface forms the linear ridges of the canyon wall. Large landslides have changed the walls and floor of the canyon. A landslide is a failure of slope due to gravity. They initiate due to several reasons. A lower layer of poorly cemented/resistant material may have been eroded, undermining the wall above which then collapses; earth quake seismic waves can cause the slope to collapse; and even an impact event near the canyon wall can cause collapse. As millions of tons of material fall and slide down slope a scalloped cavity forms at the upper part where the slope failure occurred. At the material speeds downhill it will pick up more of the underlying slope, increasing the volume of material entrained into the landslide. Whereas some landslides spread across the canyon floor forming lobate deposits, very large volume slope failures will completely fill the canyon floor in a large complex region of chaotic blocks. Tithonium Chasma is at the western end of Valles Marineris. Valles Marineris is over 4000 kilometers long, wider than the United States. Tithonium Chasma is almost 810 kilometers long (499 miles), 50 kilometers wide and over 6 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. The Odyssey spacecraft has

Melas Chasma

NASA Image and Video Library

2010-04-19

Melas Chasma is the central portion of Valles Marineris. This image taken by NASA 2001 Mars Odyssey shows a small portion of the floor of Melas Chasma, including layered deposits and wind eroded and deposited materials.

Characterization of Sulfate Minerals in Juventae Chasma from CRISM images

NASA Astrophysics Data System (ADS)

Parente, M.; Bishop, J. L.; Noe Dobrea, E.; Calvin, W.; Roach, L.; Murchie, S.

2007-12-01

We are investigating the mineralogy of the Juventae Chasma region that lies north-east of Valles Marineris. The OMEGA investigation on the Mars Express spacecraft identified sulfates in the light-toned outcrops inside Juventae Chasma (Gendrin et al 2005). In particular they observed spectral features attributed to gypsum and kieserite in the mound labelled B by Catling et al (2006). This study analyzed the geomorphology using MOC, MOLA, TES and THEMIS data and formulated hypotheses on the formation of light-toned layered outcrops labeled A to D from the South-West to the North rim of Juventae Chasma. The order of magnitude increase in spatial resolution of the CRISM instrument on Mars Reconnaissance Orbiter over OMEGA is used here to assess mineralogic diversity and to analyze stratigraphic relationships between the mounds and the surrounding Chasma walls. CRISM data show evidence for diagnostic sulfate absorptions in a few locations. These are consistent with monohydrated sulfates such as kieserite and szomolnokite as well as polyhydrated sulfates such as starkeyite. The strongest occurrences of sulfates appear at the location occupied by the light-toned outcrops, in particular mound "A". A mobile basaltic sand sheet covers much of the chasma floor. Patches of olivine and pyroxene are observed in the chasma wall rock but require further spectroscopic study to assess their extent and stratigraphic relationship with the mounds. The detection of sulfate bands in the exposed light-toned material in the mounds, which date back to late - noachian / early hesperian (Catling et al. 2006), indicates the presence of an early acidic environment in the Chasma and probable evaporitic processes. The "sulfate" layered mounds present evidence of high erosion and in some regions of exhumation from the west wall of the chasma and the hummochy terrains in the north, as visible from ConText Imager (CTX) and HiRISE data. References: Gendrin A., et al.(2005). Science, 307, 1587

Ganges River Delta, Bangladesh, India

NASA Image and Video Library

1994-11-14

The Ganges River Delta is the largest inter-tidal delta in the world. With its extensive mangrove mud flats, swamp vegetation and sand dunes, it is characteristic of many tropical and subtropical coasts. As seen in this photograph, the tributaries and distributaries of the Ganges and Brahmaputra Rivers deposit huge amounts of silt and clay that create a shifting maze of waterways and islands in the Bay of Bengal.

Investigating Mars: Ius Chasma

NASA Image and Video Library

2018-02-19

Continuing eastward along Ius Chasma, this image shows the eastern section of the large landslide deposit seen in yesterday's post. A landslide is a failure of slope due to gravity. They initiate due to several reasons. A lower layer of poorly cemented/resistant material may have been eroded, undermining the wall above which then collapses; earth quake seismic waves can cause the slope to collapse; and even an impact event near the canyon wall can cause collapse. As millions of tons of material fall and slide down slope a scalloped cavity forms at the upper part where the slope failure occurred. At the material speeds downhill it will pick up more of the underlying slope, increasing the volume of material entrained into the landslide. Whereas some landslides spread across the canyon floor forming lobate deposits, very large volume slope failures will completely fill the canyon floor in a large complex region of chaotic blocks. Ius Chasma is at the western end of Valles Marineris, south of Tithonium Chasma. Valles Marineris is over 4000 kilometers long, wider than the United States. Ius Chasma is almost 850 kilometers long (528 miles), 120 kilometers wide and over 8 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. There are many features that indicate flowing and standing water played a part in the chasma formation. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has

Investigating Mars: Ius Chasma

NASA Image and Video Library

2018-02-20

Continuing eastward along Ius Chasma, this section of the canyon floor has been completely filled by blocky deposits from large volume landslides. A landslide is a failure of slope due to gravity. They initiate due to several reasons. A lower layer of poorly cemented/resistant material may have been eroded, undermining the wall above which then collapses; earth quake seismic waves can cause the slope to collapse; and even an impact event near the canyon wall can cause collapse. As millions of tons of material fall and slide down slope a scalloped cavity forms at the upper part where the slope failure occurred. At the material speeds downhill it will pick up more of the underlying slope, increasing the volume of material entrained into the landslide. Whereas some landslides spread across the canyon floor forming lobate deposits, very large volume slope failures will completely fill the canyon floor in a large complex region of chaotic blocks. Ius Chasma is at the western end of Valles Marineris, south of Tithonium Chasma. Valles Marineris is over 4000 kilometers long, wider than the United States. Ius Chasma is almost 850 kilometers long (528 miles), 120 kilometers wide and over 8 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. There are many features that indicate flowing and standing water played a part in the chasma formation. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR

Investigating Mars: Melas Chasma

NASA Image and Video Library

2017-11-27

Melas Chasma is part of the largest canyon system on Mars, Valles Marineris. At only 563 km long (349 miles) it is not the longest canyon, but it is the widest. Located in the center of Valles Marineris, it has depths up to 9 km from the surrounding plains, and is the location of many large landslide deposits, as will as layered materials and sand dunes. There is evidence of both water and wind action as modes of formation for many of the interior deposits. This VIS image shows layered materials and sand dunes. The image is located on the mid elevations on the south side of the canyon. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 10838 Latitude: -12.7865 Longitude: 288.837 Instrument: VIS Captured: 2004-05-24 17:32 https://photojournal.jpl.nasa.gov/catalog/PIA22128

Windblown Sand in West Candor

NASA Technical Reports Server (NTRS)

2004-01-01

23 December 2003

West Candor Chasma, a part of the vast Valles Marineris trough system, is known for its layered sedimentary rock outcrops. It is less known for dark fields of windblown sand, but that is what occurs in the north-central part of the chasm. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image, obtained in December 2003, shows the interplay of dark, wind-blown sand with buttes and mesas of layered rock in west Candor Chasma. Dark streamers of sand point toward the east/southeast (right/lower right), indicating that dominant winds blow from the west. This picture is located near 5.2oS, 75.7oW, and covers an area 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

Investigating Mars: Tithonium Chasma

NASA Image and Video Library

2018-02-08

Tithonium Chasma has numerous large landslide deposits. At the bottom of this VIS image is the high plateau between Tithonium Chasma and Ius Chasma (off the bottom of the frame). The resistant material of the plateau surface forms the linear ridges of the canyon wall. Erosion of the walls cover the lower slopes. Large landslides have changed the walls and floor of the canyon. A landslide is a failure of slope due to gravity. They initiate due to several reasons. A lower layer of poorly cemented/resistant material may have been eroded, undermining the wall above which then collapses; earth quake seismic waves can cause the slope to collapse; and even an impact event near the canyon wall can cause collapse. As millions of tons of material fall and slide down slope a scalloped cavity forms at the upper part where the slope failure occurred. At the material speeds downhill it will pick up more of the underlying slope, increasing the volume of material entrained into the landslide. As the landslide material reaches the canyon bottom it spreads out and eventually comes to rest. The edge of the deposit is lobate, and may be affected by running up against pre-existing features on the canyon floor. Most Martian landslide have radial grooves on the slide surface. Tithonium Chasma is at the western end of Valles Marineris. Valles Marineris is over 4000 kilometers long, wider than the United States. Tithonium Chasma is almost 810 kilometers long (499 miles), 50 kilometers wide and over 6 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered

Investigating Mars: Melas Chasma

NASA Image and Video Library

2017-11-30

Melas Chasma is part of the largest canyon system on Mars, Valles Marineris. At only 563 km long (349 miles) it is not the longest canyon, but it is the widest. Located in the center of Valles Marineris, it has depths up to 9 km below the surrounding plains, and is the location of many large landslide deposits, as will as layered materials and sand dunes. There is evidence of both water and wind action as modes of formation for many of the interior deposits. Today's image of the southern section of the canyon shows a large region of sand dunes. The presence of dunes indicates wind action as the most recent geologic process modifying the canyon. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 18513 Latitude: -12.752 Longitude: 288.597 Instrument: VIS Captured: 2006-02-15 15:24 https://photojournal.jpl.nasa.gov/catalog/PIA22131

Investigating Mars: Candor Chasma

NASA Image and Video Library

2018-01-10

This image shows part of eastern Candor Chasma. At the bottom of the image is the steep cliff between the upper surface elevation and the depths of Candor Chasma. The small lobate feature at the base of the cliff in the bottom of the image is a landslide deposit formed by failure of the cliff face and gravitational downslope movement of the material. Candor Chasma is one of the largest canyons that make up Valles Marineris. It is approximately 810 km long (503 miles) and has is divided into two regions - eastern and western Candor. Candor is located south of Ophir Chasma and north of Melas Chasma. The border with Melas Chasma contains many large landslide deposits. The floor of Candor Chasma includes a variety of landforms, including layered deposits, dunes, landslide deposits and steep sided cliffs and mesas. Many forms of erosion have shaped Chandor Chasma. There is evidence of wind and water erosion, as well as significant gravity driven mass wasting (landslides). The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 8916 Latitude: -7.95016 Longitude: 293.509 Instrument: VIS Captured: 2003-12-18 11:38 https://photojournal.jpl.nasa.gov/catalog/PIA22162

Layers and Fractures in Ophir Chasma

NASA Image and Video Library

2015-11-05

Ophir Chasma forms the northern portion of Valles Marineris, and this image from NASA Mars Reconnaissance Orbiter spacecraft features a small part of its wall and floor. The wall rock shows many sedimentary layers and the floor is covered with wind-blown ridges, which are intermediate in size between sand ripples and sand dunes. Rocks protruding on the floor could be volcanic intrusions of once-molten magma that have pushed aside the surrounding sedimentary layers and "froze" in place. Images like this can help geologists study the formation mechanisms of large tectonic systems like Valles Marineris. (The word "tectonics" does not mean the same thing as "plate tectonics." Tectonics simply refers to large stresses and strains in a planet's crust. Plate tectonics is the main type of tectonics that Earth has; Mars does not have plate tectonics.) http://photojournal.jpl.nasa.gov/catalog/PIA20044

Investigating Mars: Melas Chasma

NASA Image and Video Library

2017-12-01

Melas Chasma is part of the largest canyon system on Mars, Valles Marineris. At only 563 km long (349 miles) it is not the longest canyon, but it is the widest. Located in the center of Valles Marineris, it has depths up to 9 km below the surrounding plains, and is the location of many large landslide deposits, as will as layered materials and sand dunes. There is evidence of both water and wind action as modes of formation for many of the interior deposits. Today's image covers part of the floor of the canyon. At the top of the image is one of the many hills found on the floor in this region. The linear grooved surface is part of a landslide deposit. Melas Chasma has many large landslide regions. Landslide deposits often have grooved surfaces with the grooves parallel to the direction of movement as the slide occurred. The ends of the landslide typically have a lobate edge, and will flow around large preexisting landforms. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 19112 Latitude: -11.1675 Longitude: 289.748 Instrument: VIS Captured: 2006-04-05 23:00 https://photojournal.jpl.nasa.gov/catalog/PIA22132

Investigating Mars: Ius Chasma

NASA Image and Video Library

2018-02-22

Chasma is almost 850 kilometers long (528 miles), 120 kilometers wide and over 8 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. There are many features that indicate flowing and standing water played a part in the chasma formation. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 26151 Latitude: -7.12079 Longitude: 275.703 Instrument: VIS Captured: 2007-11-06 12:17 https://photojournal.jpl.nasa.gov/catalog/PIA22280

Investigating Mars: Ius Chasma

NASA Image and Video Library

2018-02-19

surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. There are many features that indicate flowing and standing water played a part in the chasma formation. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 8792 Latitude: -6.69222 Longitude: 270.88 Instrument: VIS Captured: 2003-12-08 06:35 https://photojournal.jpl.nasa.gov/catalog/PIA22277

Investigating Mars: Candor Chasma

NASA Image and Video Library

2018-01-11

This image shows part of eastern Candor Chasma. At the top of the image is the steep cliff between the upper surface elevation and the depths of Candor Chasma. The bottom of the image is the cliff side of a large mesa. The two cliff faces have very different appearances. The cliff face between the top of the canyon and the bottom is likely layers of volcanic flows from the nearby Tharsis volcanoes. The mesa, however, is probably layers of sediments deposited in the canyon from wind, water and gravity driven erosion and deposition. These layered materials are much more easily eroded than the solid rock of the canyon sides. Candor Chasma is one of the largest canyons that make up Valles Marineris. It is approximately 810 km long (503 miles) and has is divided into two regions - eastern and western Candor. Candor is located south of Ophir Chasma and north of Melas Chasma. The border with Melas Chasma contains many large landslide deposits. The floor of Candor Chasma includes a variety of landforms, including layered deposits, dunes, landslide deposits and steep sided cliffs and mesas. Many forms of erosion have shaped Chandor Chasma. There is evidence of wind and water erosion, as well as significant gravity driven mass wasting (landslides). The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the

Investigating Mars: Candor Chasma

NASA Image and Video Library

2018-01-08

Candor Chasma is one of the largest canyons that make up Valles Marineris. It is approximately 810 km long (503 miles) and has is divided into two regions - eastern and western Candor. Candor is located south of Ophir Chasma and north of Melas Chasma. The border with Melas Chasma contains many large landslide deposits. The floor of Candor Chasma includes a variety of landforms, including layered deposits, dunes, landslide deposits and steep sided cliffs and mesas. Many forms of erosion have shaped Chandor Chasma. There is evidence of wind and water erosion, as well as significant gravity driven mass wasting (landslides). This image shows part of western Candor and the erosion of a large mesa. Layered materials are visible throughout the image and small dunes exist in several places. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 4360 Latitude: -6.08522 Longitude: 284.85 Instrument: VIS Captured: 2002-12-08 10:51 https://photojournal.jpl.nasa.gov/catalog/PIA22160

Investigating Mars: Candor Chasma

NASA Image and Video Library

2018-01-16

This VIS image shows part of the border between Chandor and Melas Chasmata. The entire image is landslide deposits. It is very common for landslides to develop linear surface grooves that parallel the direction of flow. Candor Chasma is one of the largest canyons that make up Valles Marineris. It is approximately 810 km long (503 miles) and has is divided into two regions - eastern and western Candor. Candor is located south of Ophir Chasma and north of Melas Chasma. The border with Melas Chasma contains many large landslide deposits. The floor of Candor Chasma includes a variety of landforms, including layered deposits, dunes, landslide deposits and steep sided cliffs and mesas. Many forms of erosion have shaped Chandor Chasma. There is evidence of wind and water erosion, as well as significant gravity driven mass wasting (landslides). The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 17003 Latitude: -8.20616 Longitude: 288.108 Instrument: VIS Captured: 2005-10-14 07:36 https://photojournal.jpl.nasa.gov/catalog/PIA22167

Investigating Mars: Hebes Chasma

NASA Image and Video Library

2017-08-14

This image shows the part of the southern cliff face of Hebes Chasma a the bottom of the image. At the top of the image is part of the large mesa located in the center of the chasma. Hebes Chasma is an enclosed basin not connected to Valles Marineris. The cliff faces of the chasma itself and the interior mesa appear quite different, which may provided information on how the chasma and the mesa formed. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 10052 Latitude: -1.5441 Longitude: 283.71 Instrument: VIS Captured: 2004-03-21 00:22 https://photojournal.jpl.nasa.gov/catalog/PIA21809

Investigating Mars: Tithonium Chasma

NASA Image and Video Library

2018-02-13

This VIS image of Tithonium Chasma shows the canyon wall at the top of the frame, a series of landslide deposits in the middle, and an eroded mound of materials at the bottom. The mound has been eroded, most likely by wind action. Tithonium Chasma has numerous large landslide deposits. The resistant material of the plateau surface forms the linear ridges of the canyon wall. Large landslides have changed the walls and floor of the canyon. A landslide is a failure of slope due to gravity. They initiate due to several reasons. A lower layer of poorly cemented/resistant material may have been eroded, undermining the wall above which then collapses; earth quake seismic waves can cause the slope to collapse; and even an impact event near the canyon wall can cause collapse. As millions of tons of material fall and slide down slope a scalloped cavity forms at the upper part where the slope failure occurred. At the material speeds downhill it will pick up more of the underlying slope, increasing the volume of material entrained into the landslide. Whereas some landslides spread across the canyon floor forming lobate deposits, very large volume slope failures will completely fill the canyon floor in a large complex region of chaotic blocks. Tithonium Chasma is at the western end of Valles Marineris. Valles Marineris is over 4000 kilometers long, wider than the United States. Tithonium Chasma is almost 810 kilometers long (499 miles), 50 kilometers wide and over 6 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. The Odyssey

Floor of Juventae Chasma

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 30 May 2002) Juventae Chasma is an enormous box canyon (250 km X 100 km) which opens to the north and forms the outflow channel Maja Vallis. Most Martian outflow channels such as Maja, Kasei, and Ares Valles begin at point sources such as box canyons and chaotic terrain and then flow unconfined into a basin region. This image captures a portion of the western floor of Juventae Chasma and shows a wide variety of landforms. Conical hills, mesas, buttes and plateaus of layered material dominate this scene and seem to be 'swimming' in vast sand sheets. The conical hills have a spur and gully topography associated with them while the flat topped buttes and mesas do not. This may be indicative of different materials that compose each of these landforms or it could be that the flat-topped layer has been completely eroded off of the conical hills thereby exposing a different rock type. Both the conical hills and flat-topped buttes and mesas have extensive scree slopes (heaps of eroded rock and debris). Ripples, which are inferred to be dunes, can also be seen amongst the hills. No impact craters can be seen in this image, indicating that the erosion and transport of material down the canyon wall and across the floor is occurring at a relatively rapid rate, so that any craters that form are rapidly buried or eroded.

Investigating Mars: Candor Chasma

NASA Image and Video Library

2018-01-15

This THEMIS image shows part of western Candor Chasma. Near the bottom of the image is an impact crater. Impact craters are relatively rare within all the canyons of Valles Marineris. The lack of craters may be due to the relative young age of the canyon system - younger surfaces on Mars have fewer craters than older surfaces. Another factor is that the high rate of erosion and deposition within the canyon erodes the ejecta blanket and fills in the crater, effectively removing the crater over time. Candor Chasma is one of the largest canyons that make up Valles Marineris. It is approximately 810 km long (503 miles) and has is divided into two regions - eastern and western Candor. Candor is located south of Ophir Chasma and north of Melas Chasma. The border with Melas Chasma contains many large landslide deposits. The floor of Candor Chasma includes a variety of landforms, including layered deposits, dunes, landslide deposits and steep sided cliffs and mesas. Many forms of erosion have shaped Chandor Chasma. There is evidence of wind and water erosion, as well as significant gravity driven mass wasting (landslides). The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit

Investigating Mars: Candor Chasma

NASA Image and Video Library

2018-01-19

This image shows part of eastern Candor Chasma. At the top of the image is the steep cliff between the upper surface elevation and the depths of Candor Chasma. The bottom of the image is the cliff side of a large mesa. The two cliff faces have very different appearances. The cliff face between the top of the canyon and the bottom is likely layers of volcanic flows from the nearby Tharsis volcanoes. The mesa, however, is probably layers of sediments deposited in the canyon from wind, water and gravity driven erosion and deposition. These layered materials are much more easily eroded than the solid rock of the canyon sides. There is a landslide that originate from the northern cliff face and ran out into the canyon floor, visible as the lobate "tongue" at the right near the center of the image. Candor Chasma is one of the largest canyons that make up Valles Marineris. It is approximately 810 km long (503 miles) and has is divided into two regions - eastern and western Candor. Candor is located south of Ophir Chasma and north of Melas Chasma. The border with Melas Chasma contains many large landslide deposits. The floor of Candor Chasma includes a variety of landforms, including layered deposits, dunes, landslide deposits and steep sided cliffs and mesas. Many forms of erosion have shaped Chandor Chasma. There is evidence of wind and water erosion, as well as significant gravity driven mass wasting (landslides). The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north

East Candor Chasma

NASA Technical Reports Server (NTRS)

1997-01-01

During its examination of Mars, the Viking 1 spacecraft returned images of Valles Marineris, a huge canyon system 5,000 km long, up to 240 km wide, and 6.5 km deep, whose connected chasma or valleys may have formed from a combination of erosional collapse and structural activity. The view shows east Candor Chasma, one of the connected valleys of Valles Marineris; north toward top of frame; for scale, the impact crater in upper right corner is 15 km (9 miles) wide. The image, centered at latitude 7.5 degrees S., longitude 67.5 degrees, is a composite of Viking 1 Orbiter high-resolution (about 80 m/pixel or picture element) images in black and white and low-resolution (about 250 m/pixel) images in color. The Viking 1 craft landed on Mars in July of 1976.

East Candor Chasma occupies the eastern part of the large west-northwest-trending trough of Candor Chasma. This section is about 150 km wide. East Candor Chasma is bordered on the north and south by walled cliffs, most likely faults. The walls may have been dissected by landslides forming reentrants; one area on the north wall shows what appears to be landslide debris. Both walls show spur-and-gully morphology and smooth sections. In the lower part of the image northwest-trending, linear depressions on the plateau are younger graben or fault valleys that cut the south wall.

Material central to the chasma shows layering in places and has been locally eroded by the wind to form flutes and ridges. These interior layered deposits have curvilinear reentrants carved into them, and in one locale a lobe flows away from the top of the interior deposit. The lobe may be mass-wasting deposits due to collapse of older interior deposits (Lucchitta, 1996, LPSC XXVII abs., p. 779- 780); this controversial idea requires that the older layered deposits were saturated with ice, perhaps from former lakes, and that young volcanism and/or tectonism melted the ice and made the material flow.

Coprates Chasma

NASA Technical Reports Server (NTRS)

1998-01-01

Mars Orbiter Camera (MOC) image of a 10 km by 12 km area of Coprates Chasma (14.7 degrees S, 55.8 degrees W), a ridge with a flat upper surface in the center of Coprates Chasma, which is part of the 6000-km-long Valles Marineris. Rock layers are visible just below the ridge. The gray scale (4.8 m/pixel) MOC image was combined with a Viking Orbiter color view of the same area. The faults of a graben offset beds on the slope to the left.

Figure caption from Science Magazine

Investigating Mars: Tithonium Chasma

NASA Image and Video Library

2018-02-14

dust and sand have modified the canyon floor, both creating and modifying layered materials. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 26775 Latitude: -4.54217 Longitude: 274.121 Instrument: VIS Captured: 2007-12-27 21:24 https://photojournal.jpl.nasa.gov/catalog/PIA22274

Melas Chasma, Day and Night.

NASA Technical Reports Server (NTRS)

2002-01-01

This image is a mosaic of day and night infrared images of Melas Chasma taken by the camera system on NASA's Mars Odyssey spacecraft. The daytime temperature images are shown in black and white, superimposed on the martian topography. A single nighttime temperature image is superimposed in color. The daytime temperatures range from approximately -35 degrees Celsius (-31 degrees Fahrenheit) in black to -5 degrees Celsius (23 degrees Fahrenheit) in white. Overlapping landslides and individual layers in the walls of Melas Chasma can be seen in this image. The landslides flowed over 100 kilometers (62 miles) across the floor of Melas Chasma, producing deposits with ridges and grooves of alternating warm and cold materials that can still be seen. The temperature differences in the daytime images are due primarily to lighting effects, where sunlit slopes are warm (bright) and shadowed slopes are cool (dark). The nighttime temperature differences are due to differences in the abundance of rocky materials that retain their heat at night and stay relatively warm (red). Fine grained dust and sand (blue) cools off more rapidly at night. These images were acquired using the thermal infrared imaging system infrared Band 9, centered at 12.6 micrometers.

Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the 2001 Mars Odyssey mission for NASA's Office of Space Science in Washington, D.C. Investigators at Arizona State University in Tempe, the University of Arizona in Tucson and NASA's Johnson Space Center, Houston, operate the science instruments. Additional science partners are located at the Russian Aviation and Space Agency and at Los Alamos National Laboratories, New Mexico. Lockheed Martin Astronautics, Denver, is the prime contractor for the project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL. Aviation and Space Agency and at Los Alamos National

East Candor Chasma

NASA Image and Video Library

1998-06-08

During its examination of Mars, NASA's Viking 1 spacecraft returned images of Valles Marineris, a huge canyon system 5,000 km long, up to 240 km wide, and 6.5 km deep, whose connected chasma or valleys may have formed from a combination of erosional collapse and structural activity. The view shows east Candor Chasma, one of the connected valleys of Valles Marineris; north toward top of frame; for scale, the impact crater in upper right corner is 15 km (9 miles) wide. The image, centered at latitude 7.5 degrees S., longitude 67.5 degrees, is a composite of Viking 1 Orbiter high-resolution (about 80 m/pixel or picture element) images in black and white and low-resolution (about 250 m/pixel) images in color. The Viking 1 craft landed on Mars in July of 1976. East Candor Chasma occupies the eastern part of the large west-northwest-trending trough of Candor Chasma. This section is about 150 km wide. East Candor Chasma is bordered on the north and south by walled cliffs, most likely faults. The walls may have been dissected by landslides forming reentrants; one area on the north wall shows what appears to be landslide debris. Both walls show spur-and-gully morphology and smooth sections. In the lower part of the image northwest-trending, linear depressions on the plateau are younger graben or fault valleys that cut the south wall. Material central to the chasma shows layering in places and has been locally eroded by the wind to form flutes and ridges. These interior layered deposits have curvilinear reentrants carved into them, and in one locale a lobe flows away from the top of the interior deposit. The lobe may be mass-wasting deposits due to collapse of older interior deposits (Lucchitta, 1996, LPSC XXVII abs., p. 779- 780); this controversial idea requires that the older layered deposits were saturated with ice, perhaps from former lakes, and that young volcanism and/or tectonism melted the ice and made the material flow. http

Double Mantle Plume Upwelling—A Possible Formation Mechanism of Beta Plateau and Devana Chasma,Venus

NASA Astrophysics Data System (ADS)

Ding, N.

2009-12-01

Ning Ding,Zuoxun Zeng,China University of Geosciences,Wuhan,430074,China NingDing.eagle@gmail.com Introduction:Venus represents a‘one plate planet’[1],and the uplift,fractures and volcanism in Beta Regio on Venus are considered to be formed by lithosphere uplift driven by a hot plume[2]. Based on the double peaking saddle landform,we suggest the tectonic pattern of double mantle plume upwelling to interpret the formation mechanism of Beta Plateau and Devana Chasma.We take a physical modeling to validate this possibility. Model:There is no ductile shear in Venus[3],so we use quartz sands to simulate the crust of Venus.We use two wood stickes 1.5cm in diameter rising from the rubber canvas slowly and straight till about half of the model,then falling down slowly and straight.The base is a hard rubber plate,in the center of which,there are two holes 3cm in diameter,and the distance between them is 5cm.The holes are covered by rubber canvas.We use the quartz sands in colours of white, red and black with particle size of 70 mess as the model materials. Result:Fig.1:At the beginning of the wood stickes upwelling,only fine radial cracks are formed above the upwelling from central to outside.With the upwelling continue,surface energy of the fine radial cracks increase and make the cracks unstable,finally,the fine radial cracks connect each other and form a fracture zone.And then the two mantle plume downwelling,the fracture zone is developed to form a chasma at the end. Fig.2:The four profiles all form reverse faults outside and normal faults inside.But the difference is the faults in the middle of the chasma goes deeper than others.It is the pattern of Beta Plateau where the tectonic rising is cut by Devana Chasma zone in the topographic features. Fig.3:From the tow fig., we can see two points similar:a.the elevation is high and distribution area is large around the area of two upwelling and it is high around the area of chasma,but the distribution area is small

Investigating Mars: Tithonium Chasma

NASA Image and Video Library

2018-02-09

Tithonium Chasma has numerous large landslide deposits. The resistant material of the plateau surface forms the linear ridges of the canyon wall. Large landslides have changed the walls and floor of the canyon. A landslide is a failure of slope due to gravity. They initiate due to several reasons. A lower layer of poorly cemented/resistant material may have been eroded, undermining the wall above which then collapses; earth quake seismic waves can cause the slope to collapse; and even an impact event near the canyon wall can cause collapse. As millions of tons of material fall and slide down slope a scalloped cavity forms at the upper part where the slope failure occurred. At the material speeds downhill it will pick up more of the underlying slope, increasing the volume of material entrained into the landslide. Whereas some landslides spread across the canyon floor forming lobate deposits, very large volume slope failures will completely fill the canyon floor in a large complex region of chaotic blocks. This VIS image shows the result of this type of landslide. Tithonium Chasma is at the western end of Valles Marineris. Valles Marineris is over 4000 kilometers long, wider than the United States. Tithonium Chasma is almost 810 kilometers long (499 miles), 50 kilometers wide and over 6 kilometers deep. In comparison, the Grand Canyon in Arizona is about 175 kilometers long, 30 kilometers wide, and only 2 kilometers deep. The canyons of Valles Marineris were formed by extensive fracturing and pulling apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR

Investigating Mars: Melas Chasma

NASA Image and Video Library

2017-11-28

Melas Chasma is part of the largest canyon system on Mars, Valles Marineris. At only 563 km long (349 miles) it is not the longest canyon, but it is the widest. Located in the center of Valles Marineris, it has depths up to 9 km below the surrounding plains, and is the location of many large landslide deposits, as will as layered materials and sand dunes. There is evidence of both water and wind action as modes of formation for many of the interior deposits. This VIS image highlights the extent of layered materials within the canyon. The image is located on the mid elevations on the south side of the canyon. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 10813 Latitude: -13.1037 Longitude: 289.967 Instrument: VIS Captured: 2004-05-22 16:09 https://photojournal.jpl.nasa.gov/catalog/PIA22129

Headward growth of chasmata by volatile outbursts, collapse, and drainage: Evidence from ganges chaos, Mars

USGS Publications Warehouse

Rodriguez, J.A.P.; Kargel, J.; Crown, D.A.; Bleamaster, L. F.; Tanaka, K.L.; Baker, V.; Miyamoto, H.; Dohm, J.M.; Sasaki, S.; Komatsu, G.

2006-01-01

The nature and significance of collapse processes in Capri, Eos, and Ganges Chasmata remain poorly understood. Using Ganges Chasma as a type locality, these chasmata are interpreted to be the result of clustering and assimilation of multiple chaotic terrains, which primarily formed by localized depressurization-induced or thermally-triggered dissociation of buried gas clathrate hydrates and explosive eruption of gas-saturated ground water. Such crustal destabilization could have been triggered by (1) deep fracture propagation from the Martian surface, (2) magmatic intrusions and associated heating and inflation-induced terrain fracturing, and/or (3) climatic thaw and thinning/weakening of the permafrost over the clathrate and gas-rich groundwater zones. Volume increases associated with release of gases contributed to the xpulsion of groundwater and fluidized sediments at the surface, thereby carving the higher outflow channels peripheral to the chasmata and the lower outflow channel floors of the chasmata and outflow channels. Copyright 2006 by the American Geophysical Union.

West Candor Chasma

NASA Technical Reports Server (NTRS)

1996-01-01

During its examination of Mars, the Viking 1 spacecraft returned images of Valles Marineris, a huge canyon system 5,000 km long, up to 240 km wide, and 6.5 km deep, whose connected chasma or valleys may have formed from a combination of erosional collapse and structural activity. The view shows west Candor Chasma, one of the connected valleys of Valles Marineris; north toward top of frame. The image is a composite of Viking high-resolution (about 80 m/pixel or picture element) images in black and white and low resolution (about 250 m/pixel) images in color. The Viking 1 craft landed on Mars in July of 1976. West Candor Chasma occupies the westernmost part of the large west-northwest-trending trough of Candor Chasma. This section is about 150 km wide. West Candor Chasma is bordered on the north and south by straight-walled cliffs, most likely faults, and on its west by two segments of north-northeast-trending cliffs. The north wall is dissected by landslide scars forming reentrants filled with landslide debris. The south wall shows spur-and-gully morphology and smooth sections. The high-standing central mesa, informally dubbed Red Mesa has several curvilinear reentrants carved into the caprock, whose anomalously colored layers were interpreted to be caused by young hydrothermal alteration products (Geissler et al., 1993, Icarus, v. 106, p. 380-391). Light-colored lobes flow away from the top of the interior stack and then flow around and embay the same layered stack from which they originated. One of these apparent flow features is composed of at least two or perhaps even three huge, superposed, vaguely layered, very rugged, light-colored lobes as much as 100 km long, 20 km wide, and over 2 km thick. The layered deposits below the caprock also merge with a chaotic material that has local lobate fronts and overlaps landslide deposits. Hummocky material, similar in hue to wall rock, fills the southwestern-most region of west Candor Chasma and is perhaps as much as 3

Investigating Mars: Melas Chasma

NASA Image and Video Library

2017-12-05

Melas Chasma is part of the largest canyon system on Mars, Valles Marineris. At only 563 km long (349 miles) it is not the longest canyon, but it is the widest. Located in the center of Valles Marineris, it has depths up to 9 km below the surrounding plains, and is the location of many large landslide deposits, as will as layered materials and sand dunes. There is evidence of both water and wind action as modes of formation for many of the interior deposits. Today's image is just a bit further to the west of yesterday's. Here there are no dunes, but extensive outcrops of layered material. It is possible that these layered deposits were formed by sediments settling in a lake. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 4335 Latitude: -10.3718 Longitude: 285.195 Instrument: VIS Captured: 2002-12-06 09:30 https://photojournal.jpl.nasa.gov/catalog/PIA22135

Investigating Mars: Melas Chasma

NASA Image and Video Library

2017-12-06

Melas Chasma is part of the largest canyon system on Mars, Valles Marineris. At only 563 km long (349 miles) it is not the longest canyon, but it is the widest. Located in the center of Valles Marineris, it has depths up to 9 km below the surrounding plains, and is the location of many large landslide deposits, as will as layered materials and sand dunes. There is evidence of both water and wind action as modes of formation for many of the interior deposits. This VIS image is located right at the edge of the canyon with the surrounding plains - the flat area at the bottom of the image. Some small landslide deposits are visible originating at the cliff side. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 26762 Latitude: -13.4233 Longitude: 287.973 Instrument: VIS Captured: 2007-12-26 19:46 https://photojournal.jpl.nasa.gov/catalog/PIA22136

Investigating Mars: Melas Chasma

NASA Image and Video Library

2017-11-29

Melas Chasma is part of the largest canyon system on Mars, Valles Marineris. At only 563 km long (349 miles) it is not the longest canyon, but it is the widest. Located in the center of Valles Marineris, it has depths up to 9 km below the surrounding plains, and is the location of many large landslide deposits, as will as layered materials and sand dunes. There is evidence of both water and wind action as modes of formation for many of the interior deposits. This VIS image shows part of a large ridge of material near the south central part the canyon. The roughest looking material is the top of the ridge. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 16741 Latitude: -10.6629 Longitude: 285.637 Instrument: VIS Captured: 2005-09-22 17:54 https://photojournal.jpl.nasa.gov/catalog/PIA22130

Investigating Mars: Melas Chasma

NASA Image and Video Library

2017-12-04

Melas Chasma is part of the largest canyon system on Mars, Valles Marineris. At only 563 km long (349 miles) it is not the longest canyon, but it is the widest. Located in the center of Valles Marineris, it has depths up to 9 km below the surrounding plains, and is the location of many large landslide deposits, as will as layered materials and sand dunes. There is evidence of both water and wind action as modes of formation for many of the interior deposits. Today's image contains a large region of dunes between the canyon cliff face and the large ridge of material at the mid-elevation of the canyon. Fine materials have been concentrated into the dunes. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 26525 Latitude: -11.3125 Longitude: 285.57 Instrument: VIS Captured: 2007-12-07 07:23 https://photojournal.jpl.nasa.gov/catalog/PIA22134

A secondary origin for the central plateau of Hebes Chasma

NASA Technical Reports Server (NTRS)

Peterson, C.

1982-01-01

Hebes Chasma, one of the northern members of the Valles Marineris, can be divided into three physiographic provinces; chasma walls, chasma floor, and central plateau. Theories of origin of the 5-kilometer-high central plateau include (1) the plateau is an eroded remnant of the surrounding plains, and (2) the plateau is a secondary feature deposited after formation of the chasma. A secondary eolian or pyroclastic origin best explains the morphology of the plateau. The chasma probably formed by collapse of a pre-existing graben that was widened by landslides and subsequently filled with eolian or pyroclastic material. Continued mass wasting isolated the plateau from the chasma walls. The enclosed nature of Hebes Chasma may have inhibited eolian erosion and transport within the trough, so that the relatively fresh appearance of the plateau has been preserved.

Melas Chasma

NASA Image and Video Library

2016-12-05

Today's VIS image shows part of the canyon wall of Melas Chasma. Orbit Number: 65682 Latitude: -9.38343 Longitude: 289.417 Instrument: VIS Captured: 2016-10-04 02:52 http://photojournal.jpl.nasa.gov/catalog/PIA21181

Investigating Mars: Tithonium Chasma

NASA Image and Video Library

2018-02-12

walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 19200 Latitude: -4.54491 Longitude: 272.164 Instrument: VIS Captured: 2006-04-13 04:51

Candor Chasma

NASA Technical Reports Server (NTRS)

1998-01-01

Complex central deposits in the floor of the Candor Chasma section of Vallis Marineris. This 3.3 x 3.1 km image (frame 8405) is centered near 6.7 degrees south, 75.4 degrees west.

Figure caption from Science Magazine

Sedimentary Deposits within Ius Chasma

NASA Image and Video Library

2015-07-15

Sedimentary deposits are common within Valles Marineris. Most larger chasmata contain kilometer-thick light-toned layered deposits composed of sulfates. However, some of the chasmata, like Ius Chasma shown in this image from NASA Mars Reconnaissance Orbiter, lack these deposits or have much thinner deposits. The light-toned deposits in Ius Chasma are observed both along the floor and inner wallrock materials. Some of the light-toned deposits appear to post-date formation of the chasma floor, whereas other deposits appear to lie beneath wallrock materials, indicating they are older. By examining the stratigraphy using digital terrain models and 3D images, it should be possible to decipher the relative ages of the different geologic units. CRISM data may also provide insight into the mineralogy, which will tell scientists about the aqueous conditions that emplaced the light-toned deposits. http://photojournal.jpl.nasa.gov/catalog/PIA19855

Hydrated mineral stratigraphy of Ius Chasma, Valles Marineris

USGS Publications Warehouse

Roach, L.H.; Mustard, J.F.; Swayze, G.; Milliken, R.E.; Bishop, J.L.; Murchie, S.L.; Lichtenberg, K.

2010-01-01

New high-resolution spectral and morphologic imaging of deposits on walls and floor of Ius Chasma extend previous geomorphic mapping, and permit a new interpretation of aqueous processes that occurred during the development of Valles Marineris. We identify hydrated mineralogy based on visible-near infrared (VNIR) absorptions. We map the extents of these units with CRISM spectral data as well as morphologies in CTX and HiRISE imagery. Three cross-sections across Ius Chasma illustrate the interpreted mineral stratigraphy. Multiple episodes formed and transported hydrated minerals within Ius Chasma. Polyhydrated sulfate and kieserite are found within a closed basin at the lowest elevations in the chasma. They may have been precipitates in a closed basin or diagenetically altered after deposition. Fluvial or aeolian processes then deposited layered Fe/Mg smectite and hydrated silicate on the chasma floor, postdating the sulfates. The smectite apparently was weathered out of Noachian-age wallrock and transported to the depositional sites. The overlying hydrated silicate is interpreted to be an acid-leached phyllosilicate transformed from the underlying smectite unit, or a smectite/jarosite mixture. The finely layered smectite and massive hydrated silicate units have an erosional unconformity between them, that marks a change in surface water chemistry. Landslides transported large blocks of wallrock, some altered to contain Fe/Mg smectite, to the chasma floor. After the last episode of normal faulting and subsequent landslides, opal was transported short distances into the chasma from a few m-thick light-toned layer near the top of the wallrock, by sapping channels in Louros Valles. Alternatively, the material was transported into the chasma and then altered to opal. The superposition of different types of hydrated minerals and the different fluvial morphologies of the units containing them indicate sequential, distinct aqueous environments, characterized by alkaline

Investigating Mars: Tithonium Chasma

NASA Image and Video Library

2018-02-15

apart of the crust during the uplift of the vast Tharsis plateau. Landslides have enlarged the canyon walls and created deposits on the canyon floor. Weathering of the surface and influx of dust and sand have modified the canyon floor, both creating and modifying layered materials. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 71,000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 35746 Latitude: -4.47838 Longitude: 272.133 Instrument: VIS Captured: 2010-01-04 14:22 https://photojournal.jpl.nasa.gov/catalog/PIA22275

Bullying and gangs.

PubMed

White, Rob; Mason, Ron

2012-01-01

Although bullying is associated with gangs, questions arise as to whether bullying, as such, takes place within gangs. To provide a critical analysis of bullying as this pertains to youth gangs and especially to violence within gangs, and as applied to the behaviour of individual gang members. Young men between 12 and 25 years of age. Review of relevant literature with a view to theorising the nature of the relationship between bullying and violence within a youth gang context. Bullying is associated with the reasons why individuals join gangs and with gang-related behaviour, but the violence within a gang is of a different character than that usually described by the term bullying. Bullying has implications for related and/or subsequent types of street violence, but is less relevant for descriptions of violence within a youth gang context as such.

Youth Gangs: An Overview. Juvenile Justice Bulletin. Youth Gang Series.

ERIC Educational Resources Information Center

Howell, James C.

1998-01-01

This bulletin provides an overview of the problems that youth gangs pose. It pinpoints the differences between youth gangs and adult criminal organizations and examines the risk factors that lead to youth gang membership. Some promising strategies being used to curb youth gang involvement are reviewed. The proliferation of youth gangs since 1980…

Hebes Chasma #1

NASA Technical Reports Server (NTRS)

1998-01-01

Complex variations in dune forms within Hebes Chasma. This northern subframe image, frame 3506, is a 2.3 x 3.6 km area centered near 0.6 degrees south, 76.3 degrees west.

Figure caption from Science Magazine

Hebes Chasma #2

NASA Technical Reports Server (NTRS)

1998-01-01

Complex variations in dune forms within Hebes Chasma. This southern subframe image, frame 3506, is a 2.3 x 3.6 km area centered near 0.8 degrees south, 76.3 degrees west

Figure caption from Science Magazine

Melas Chasma Deposits

NASA Image and Video Library

2003-01-09

Erosion of the interior layered deposits of Melas Chasma, part of the huge Valles Marineris canyon system, has produced cliffs with examples of spur and gulley morphology and exposures of finely layered sediments, as seen in this NASA Mars Odyssey image.

Candor Chasma Mesa

NASA Image and Video Library

2003-01-09

In this image from NASA Mars Odyssey, a mantling layer of sediment slumps off the edge of a mesa in Candor Chasma producing a ragged pattern of erosion that hints at the presence of a volatile component mixed in with the sediment.

Candor Chasma - Massive (non-layered) material expos

NASA Technical Reports Server (NTRS)

1998-01-01

potential to reveal information about the early history and evolution of the red planet. The MOC Science Team is continuing to examine the wealth of new data and planning for new Valles Marineris targets once the Mapping Phase of the Mars Global Surveyor mission commences in March 1999.

This image: Massive (non-layered) material exposed in central Candor Chasma. MOC image 25205 subframe shown at 11.7 meters (38.4 feet) per pixel resolution. Image shows the southern tip of a massive 'interior deposit' that points like a giant tongue from Ophir Chasma (to the north) down into the center of Candor Chasma. The ridged and grooved bright unit is the 'interior deposit'. South of this ridged unit is a low elevation surface mantled by dark dunes and sand. Image covers an area approximately 5.7 by 5.7 kilometers (3.5 x 3.5 miles). North is approximately up, illumination is from the lower right. Image 25205 was obtained during Mars Global Surveyor's 252nd orbit at 2:45 p.m. (PDT) on April 20, 1998.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

Ophir Chasma - False Color

NASA Image and Video Library

2016-04-28

The THEMIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image from NASA 2001 Mars Odyssey spacecraft shows part of Ophir Chasma.

Mass wasting features in Juventae Chasma, Mars

NASA Astrophysics Data System (ADS)

Sarkar, Ranjan; Singh, Pragya; Porwal, Alok; Ganesh, Indujaa

2016-07-01

Introduction : We report mass-wasting features preserved as debris aprons from Juventae Chasma. Diverse lines of evidence and associated geomorphological features indicate that fluidized ice or water within the wall rocks of the chasma could be responsible for mobilizing the debris. Description : The distinctive features of the landslides in Juvenate Chasma are: (1) lack of a well-defined crown or a clear-cut section at their point of origin and instead the presence of amphitheatre-headed tributary canyons; (2) absence of slump blocks; (3) overlapping of debris aprons; (4) a variety of surface textures from fresh and grooved to degraded and chaotic; (5) rounded lobes of debris aprons; (6) large variation of sizes from small lumps (~0.52 m2) to large tongue shaped ones (~ 80 m2); (7) smaller average size of landslides as compared to other chasmas; and (8) occasional preservation of fresh surficial features indicating recent emplacement. Discussion : Amphitheatre-headed tributary canyons, which are formed due to ground water sapping, indicate that the same was responsible for wall-section collapse, although a structural control cannot be completely ruled out. The emplacement of the mass wasting features preferentially at the mouths of amphitheatre-headed tributary canyons along with the rounded flow fronts of the debris suggest fluids may have played a vital role in their emplacement. The mass-wasting features in Juventae Chasma are unique compared to other landslides in Valles Marineris despite commonalities such as the radial furrows, fan-shaped outlines, overlapping aprons and overtopped obstacles. The unique set of features and close association with amphitheatre-headed tributary canyons imply that the trigger of the landslides was not structural or tectonic but possibly weakness imparted by the presence of water or ice in the pore-spaces of the wall. Craters with fluidized ejecta blankets and scalloped depressions in the surrounding plateau also support this

Coprates Chasma - False Color

NASA Image and Video Library

2015-01-08

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image from NASA 2001 Mars Odyssey spacecraft shows part of Coprates Chasma.

Coprates Chasma - False Color

NASA Image and Video Library

2016-03-11

The THEMIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This image from NASA 2001 Mars Odyssey spacecraft shows part of the floor of Coprates Chasma.

Coprates Chasma - False Color

NASA Image and Video Library

2015-01-01

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image from NASA 2001 Mars Odyssey spacecraft shows part of Coprates Chasma.

Light-Toned Layers in Tithonium Chasma

NASA Image and Video Library

2015-08-12

Tithonium Chasma is a part of Valles Marineris, the largest canyon in the Solar System. If Valles Marineris was located on Earth, at more than 4,000 kilometers long and 200 kilometers wide, it would span across almost the entire United States. Tithonium Chasma is approximately 800 kilometers long. A "chasma," as defined by the International Astronomical Union, is an elongate, steep-sided depression. The walls of canyons often contain bedrock exposing numerous layers. In some regions, light-toned layered deposits erode faster than the darker-toned ones. The layered deposits in the canyons are of great interest to scientists, as these exposures may shed light on past water activity on Mars. The CRISM instrument on MRO indicates the presence of sulfates, hydrated sulfates, and iron oxides in Tithonium Chasma. Because sulfates generally form from water, the light-toned sulfate rich deposits in the canyons may contain traces of ancient life. The mid-section of this image is an excellent example of the numerous layered deposits, known as interior layered deposits. The exact nature of their formation is still unclear. However, some layered regions display parallelism between strata while other regions are more chaotic, possibly due to past tectonic activity. Lobe-shaped deposits are associated with depositional morphologies, considered indicative of possible periglacial activity. Overall, the morphological and lithological features we see today are the result of numerous geological processes, indicating that Mars experienced a diverse and more active geological past. http://photojournal.jpl.nasa.gov/catalog/PIA19868

Coprates Chasma - False Color

NASA Image and Video Library

2014-12-10

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image captured by NASA 2001 Mars Odyssey spacecraft shows part of Coprates Chasma.

Hebes Chasma - False Color

NASA Image and Video Library

2014-12-08

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image captured by NASA 2001 Mars Odyssey spacecraft shows part of Hebes Chasma.

Melas Chasma - False Color

NASA Image and Video Library

2014-12-09

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image captured by NASA 2001 Mars Odyssey spacecraft shows part of Melas Chasma.

Coprates Chasma - False Color

NASA Image and Video Library

2014-12-11

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image captured by NASA 2001 Mars Odyssey spacecraft shows part of Coprates Chasma.

Eos Chasma - False Color

NASA Image and Video Library

2014-12-16

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image from NASA 2001 Mars Odyssey spacecraft shows part of of Eos Chasma.

Pargo Chasma and its relationship to global tectonics

NASA Technical Reports Server (NTRS)

Ghail, R. C.

1993-01-01

Pargo Chasma was first identified on Pioneer Venus data as a 10,000 km long lineation extending from Atla Regio in the north terminating in the plains south of Phoebe Regio. More recent Magellan data have revealed this feature to be one of the longest chains of coronae so far identified on the planet. Stofan et al have identified 60 coronae and 2 related features associated with this chain; other estimates differ according to the classification scheme adopted, for example Head et al. identify only 29 coronae but 43 arachnoids in the same region. This highlights one of the major problems associated with the preliminary mapping of the Magellan data: there has been an emphasis on identifying particular features on Venus without a universally accepted scheme to classify those features. Nevertheless, Pargo Chasma is clearly identified as a major tectonic belt of global significance. Together with the Artemis-Atla-Beta tectonic zone and the Beta-Phoebe rift belt, Pargo Chasma defines a region on Venus with an unusually high concentration of tectonic and volcanic features. Thus, an understanding of the processes involved in the formation of Pargo Chasma may lend significant insight into the evolution of the region and the planet as a whole. I have produced a detailed 1 to 10 million scale map of Pargo Chasma and the surrounding area from preliminary USGS controlled mosaiced image maps of Venus constructed from Magellan data. In view of the problems highlighted above in relation the efforts already made at identifying a particular set of features I have mapped the region purely on the basis of the geomorphology visible in the magellan data without any attempt at identifying a particular set or class of features. Thus, the map produced distinguishes between areas of different brightness and texture. This has the advantage of highlighting the tectonic fabric of Pargo Chasma and clearly illustrates the close inter-relationship between individual coronae and the surrounding

Becoming a Gang Member: Youth Life and Gang Youth

ERIC Educational Resources Information Center

Morch, Sven; Andersen, Helle

2012-01-01

The purpose of this paper is to develop a framework for understanding the growth in youth gangs and gang behaviour. The paper builds on a youth theory perspective and describes how the social conditions work with or are against the young individual in such a way that gangs seem to be an option or an answer for some young people when faced with…

Investigating Mars: Hebes Chasma

NASA Image and Video Library

2017-08-17

The large mesa in the center of Hebes Chasma dominates this image. The top of the mesa is at the center of the image, with the cliff faces to the top and bottom of the image. The layering of the mesa is most easily identified in the lower part of the image. The long linear depression on the northern face indicate that wind action played a large part in eroding the mesa. Hebes Chasma is an enclosed basin not connected to Valles Marineris. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 15281 Latitude: -1.13682 Longitude: 283.509 Instrument: VIS Captured: 2005-05-25 12:52 https://photojournal.jpl.nasa.gov/catalog/PIA21812

Eolian Features Provide a Glimpse of Candor Chasma Mineralology

NASA Technical Reports Server (NTRS)

2008-01-01

This image of Candor Chasma's eastern end was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at 0655 UTC (2:55 a.m. EDT) on March 24, 2007. CRISM's image captured 544 colors covering 0.36-3.92 micrometers, and shows features as small as 100 meters (330 feet) across. The region covered is roughly 10 kilometers (6.2 miles) at its narrowest point. Designed to look for a variety of materials on the walls and floor of Candor Chasma, this CRISM observation is somewhat unique in that it is extended along an extended path across the chasma floor to capture extra territory at the expense of spatial resolution.

Candor Chasma is a deep, elongated, steep-sided depression some 813 kilometers (505 miles) in length. It is one of two large chasmata that make up the northern end of the Valles Marineris system. The top image, which illustrates the long path CRISM's cameras scanned to extend the observation in the along-track direction, shows the CRISM image on top of a mosaic of images from the Thermal Emission Imaging System (THEMIS) on Mars Odyssey. The lower two false-color images offer a glimpse of the topography and mineralogy contained within this large chasma. These views were constructed by draping the CRISM images over topography, and viewing the surface in perspective from the northeast. The southern part of CRISM's swath (to the left) covers interior layered deposits along with low ridges (far left) that are an erosional remnant of the chasma wall. The northern end (to the right) reveals the older, eroded chasma wall material, as well as the chasma floor. White lines in the images represent gaps in the data due to the stretching of the image.

The erosive Martian wind appears to have removed dust and debris covering monohydrated sulfate-rich mineral deposits (bright green). Wind-abraded ridges of layered sediments (image center) reveal these deposits more readily, while ridges to the north and south also appear to retain more of a

Melas Chasma, Day and Night.

NASA Image and Video Library

2002-12-07

This image is a mosaic of day and night infrared images of Melas Chasma taken by NASA Mars Odyssey spacecraft. The daytime temperature images are shown in black and white, superimposed on the Martian topography.

Differentiating Gang Members, Gang Affiliates, and Violent Men on Their Psychiatric Morbidity and Traumatic Experiences.

PubMed

Wood, Jane L; Kallis, Constantinos; Coid, Jeremy W

2017-01-01

Little is known about the differences between gang members and gang affiliates-or those individuals who associate with gangs but are not gang members. Even less is known about how these groups compare with other violent populations. This study examined how gang members, gang affiliates, and violent men compare on mental health symptoms and traumatic experiences. Data included a sample of 1,539 adult males, aged 19 to 34 years, taken from an earlier survey conducted in the United Kingdom. Participants provided informed consent before completing questionnaires and were paid £5 for participation. Logistic regression analyses were conducted to compare participants' symptoms of psychiatric morbidity and traumatic event exposure. Findings showed that, compared to violent men and gang affiliates, gang members had experienced more severe violence, sexual assaults, and suffered more serious/life-threatening injuries. Compared to violent men, gang members and gang affiliates had made more suicide attempts; had self-harmed more frequently; and had experienced more domestic violence, violence at work, homelessness, stalking, and bankruptcy. Findings further showed a decreasing gradient from gang members to gang affiliates to violent men in symptom levels of anxiety, antisocial personality disorder, pathological gambling, stalking others, and drug and/or alcohol dependence. Depression symptoms were similar across groups. The identified relationship between gang membership, affiliation, and adverse mental health indicates that mental health in gang membership deserves more research attention. Findings also indicate that criminal justice strategies need to consider gang members' mental health more fully, if gang membership is to be appropriately addressed and reduced.

Gangs in America.

ERIC Educational Resources Information Center

Huff, C. Ronald, Ed.

This book comprised of theories and findings from researchers concerning youth gangs in the United States, is organized into the following five parts: (1) Sociological and Anthropological Perspectives on the Gang and the Community; (2) Defining and Measuring Gang Violence; (3) Diffusion, Diversity, and Drugs; (4) Assessing the Changing Knowledge…

DIFFERENT STROKES FOR DIFFERENT GANGS? AN ANALYSIS OF CAPITAL AMONG LATINO AND ASIAN GANG MEMBERS

PubMed Central

PIH, KAY KEI-HO; DE LA ROSA, MARIO; RUGH, DOUGLAS; MAO, KUORAY

2009-01-01

Gang activity and membership were noted to be significantly related to financial rewards. As such, gang membership and gang activity should also be understood from an economic perspective. In this article, Pierre Bourdieu's framework of capital is used to analyze two separate samples of Latino and Asian gang members. Stark contrasts in socioeconomic backgrounds are recorded among the two samples of gang members, and gang membership and activities are also noticeably dissimilar. Accessibility to economic, cultural, and social capital is argued to affect gang membership and activities. The results suggest that the availability of legitimate and illegitimate capital greatly affects the trajectory and the length of gang involvement. Also, gangs provide significant material and social capital for the respondents of the study. PMID:19578563

Gangs and Schools.

ERIC Educational Resources Information Center

Arthur, Richard; Erickson, Edsel

This book explores the U.S. gang problem, based on the author's 35 years of experience as a high school and junior high school teacher, principal, and community organizer in Oakland and Los Angeles (California). Chapters discuss the subculture of gang worlds, reasons why youth are attracted to gangs, how educators can reach out to students, the…

Gangs in Central America

DTIC Science & Technology

2007-08-02

Societal stigmas against gangs and gang- deportees from the United States have made the process of leaving a gang extremely difficult. A recent...often unwilling to hire them. Tattooed former gang members, especially returning deportees from the United States who are often native English...recipients of deportees on a per capita basis. For all Central American countries, with the exception of Panama, those deported on criminal grounds

Gangs in Central America

DTIC Science & Technology

2008-10-17

livelihood, and protection. Societal Stigmas. Societal stigmas against gangs and gang- deportees from the United States have made the process of leaving...Ex-gang members report that employers are often unwilling to hire them. Tattooed former gang members, especially returning deportees from the United...American countries, with the exception of Panama, have a lower percentage of criminal deportees than the regional average. For example, criminal

Origin of collapsed pits and branched valleys surrounding the Ius chasma on Mars

NASA Astrophysics Data System (ADS)

Vamshi, G. T.; Martha, T. R.; Vinod Kumar, K.

2014-11-01

Chasma is a deep, elongated and steep sided depression on planetary surfaces. Several hypothesis have been proposed regarding the origin of chasma. In this study, we analysed morphological features in north and south of Ius chasma. Collapsed pits and branched valleys alongwith craters are prominent morphological features surrounding Ius Chasma, which forms the western part of the well known Valles Marineris chasma system on Martian surface. Analysis of images from the High Resolution Stereo Camera (HRSC) in ESA's Mars Express (MEX) with a spatial resolution of 10 m shows linear arrangement of pits north of the Ius chasma. These pits were initially developed along existing narrow linear valleys parallel to Valles Merineris and are conical in shape unlike flat floored impact craters found adjacent to them. The width of conical pits ranges 1-10 km and depth ranges 1-2 km. With more subsidence, size of individual pits increased gradually and finally coalesced together to create a large depression forming a prominent linear valley. Arrangement of pits in this particular fashion can be attributed to collapse of the surface due to l arge hollows created in the subsurface because of the withdrawal of either magma or dry ice. Branched valleys which are prominent morphologic features south of the Ius chasma could have been formed due to groundwater sapping mechanism as proposed by previous researchers. Episodic release of groundwater in large quantity to the surface could have resulted in surface runoff creating V-shaped valleys, which were later modified into U-shaped valleys due to mass wasting and lack of continued surface runoff.

Geologic Mapping of the Devana Chasma (V-29) Quadrangle, Venus

NASA Technical Reports Server (NTRS)

Tandberg, E. R.; Bleamaster, L. F., III

2010-01-01

The Devana Chasma quadrangle (V-29; 0-25degN/270-300degE) is situated over the northeastern apex of the Beta-Atla-Themis (BAT) province and includes the southern half of Beta Regio, the northern and transitional segments of the Devana Chasma complex, the northern reaches of Phoebe Regio, Hyndla Regio, and Nedolya Tesserae, and several smaller volcano-tectonic centers and impact craters.

The Gang Intervention Handbook.

ERIC Educational Resources Information Center

Goldstein, Arnold P., Ed.; Huff, C. Ronald, Ed.

This book provides overviews and evaluations of current juvenile-gang-intervention programs and recommends approaches that have been effective in both prevention and rehabilitation. Its three parts, composed of individual essays, examine patterns of ganging and gang intervention, explore the value of psychology-based interventions, and discuss the…

Urban Street Gang Enforcement.

ERIC Educational Resources Information Center

Institute for Law and Justice, Inc., Alexandria, VA.

Strategies to enhance prosecution of gang-related crimes are presented, with a focus on enforcement and prosecution targeting urban street gangs. The model programs introduced offer strategies largely based on the practical experiences of agencies that participated in a demonstration program, the Urban Street Gang Drug Trafficking Enforcement…

Gangs: The Origins and Impact of Contemporary Youth Gangs in the United States.

ERIC Educational Resources Information Center

Cummings, Scott, Ed.; Monti, Daniel J., Ed.

This book presents papers from some leading social scientists and scholars who examine the contemporary contours of America's gang problem. New material is provided on wilding (i.e., running amok for no specific reason) gangs, migration and drug trafficking, and public education disruption. Other topics involve organization of gangs, their social…

Melas Chasma - False Color

NASA Image and Video Library

2015-02-27

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. This false color image from NASA 2001 Mars Odyssey spacecraft shows part of Melas Chasma. Orbit Number: 4622 Latitude: -12.797 Longitude: 288.629 Instrument: VIS Captured: 2002-12-30 00:28 http://photojournal.jpl.nasa.gov/catalog/PIA19218

Long Range View of Melas Chasma

NASA Image and Video Library

2002-12-07

This image is a mosaic of day and night infrared images of Melas Chasma taken by NASA Mars Odyssey spacecraft. The daytime temperatures range from approximately -35 degrees Celsius -31 degrees Fahrenheit to -5 degrees Celsius 23 degrees Fahrenheit.

Structural geology of Amazonian-aged layered sedimentary deposits in southwest Candor Chasma, Mars

USGS Publications Warehouse

Okubo, C.H.

2010-01-01

The structural geology of an outcropping of layered sedimentary deposits in southwest Candor Chasma is mapped using two adjacent high-resolution (1 m/pixel) HiRISE digital elevation models and orthoimagery. Analysis of these structural data yields new insight into the depositional and deformational history of these deposits. Bedding in non-deformed areas generally dips toward the center of west Candor Chasma, suggesting that these deposits are basin-filling sediments. Numerous kilometer-scale faults and folds characterize the deformation here. Normal faults of the requisite orientation and length for chasma-related faulting are not observed, indicating that the local sediments accumulated after chasma formation had largely ceased in this area. The cause of the observed deformation is attributed to landsliding within these sedimentary deposits. Observed crosscutting relationships indicate that a population of sub-vertical joints are the youngest deformational structures in the area. The distribution of strain amongst these joints, and an apparently youthful infill of sediment, suggests that these fractures have been active in the recent past. The source of the driving stress acting on these joints has yet to be fully constrained, but the joint orientations are consistent with minor subsidence within west Candor Chasma.

Mars Odyssey All Stars: Chasma Boreale

NASA Image and Video Library

2010-12-09

Chasma Boreale is a long, flat-floored valley that cuts deep into Mars north polar icecap. This image is part of an All Star set marking the occasion of NASA Mars Odyssey as the longest-working Mars spacecraft in history.

Possible Sulfate Deposits in West Melas Chasma

NASA Image and Video Library

2016-05-04

Melas Chasma is the widest segment of Valles Marineris, the largest canyon in the Solar System as seen by Mars Reconnaissance Orbiter spacecraft. In this region, hydrated sulfate salts have been detected.

Modern-Day Youth Gangs. OJJDP, Juvenile Justice Bulletin.

ERIC Educational Resources Information Center

Howell, James C.; Egley, Arlen, Jr.; Gleason, Debra K.

This report draws on data from the 1996 and 1998 National Youth Gang Surveys to compare the characteristics of gangs and gang members in jurisdictions with later onset of gang problems with those of gangs and gang members with earlier onset of gang problems. The survey asked respondents from law enforcement agencies to describe when gangs began to…

Gangs in Central America

DTIC Science & Technology

2008-03-27

deportees from the United States have made the process of leaving a gang extremely difficult. A recent State Department report on youth gangs in El...gang members, especially returning deportees from the United States who are often native English speakers, have had the most difficulty finding...with the exception of Panama, have a much lower percentage of criminal deportees than the regional average of 39%. For example, criminal deportees

Gangs a Suburban Problem Too! "Taking the Gang Threat Seriously."

ERIC Educational Resources Information Center

Stabile, Michael J.

Gangs are no longer the exclusive problem of large metropolitan areas. Suburban schools and communities are now vulnerable, and the problem is spreading. To combat the problem, it is essential to overcome denial in the school and community. The case study of Chris, a junior high school student, exemplifies suburban youth gang members.…

Responding to Gangs: Evaluation and Research.

ERIC Educational Resources Information Center

Reed, Winifred L., Ed.; Decker, Scott H., Ed.

This collection of papers presents a representative selection of the National Institute of Justice's portfolio of gang-related research. The 10 papers are: (1) "A Decade of Gang Research: Findings of the National Institute of Justice Gang Portfolio" (Scott H. Decker); (2) "The Evolution of Street Gangs: An Examination of Form and…

Cults as Gangs.

ERIC Educational Resources Information Center

Cantrell, Mary Lynn

1992-01-01

Considers cults as gangs, but also distinguishes cults from gangs by the cult's reference to and insistence on allegiance to single higher authority, usually spirit figure or spiritual leader. Examines Satanism, identifies Satanic holidays and symbols, and describes characteristics of cult-influenced youth. Includes list of organizations and books…

Melas Chasma - False Color

NASA Image and Video Library

2017-07-13

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. These false color images may reveal subtle variations of the surface not easily identified in a single band image. Today's false color image shows part of Melas Chasma. Orbit Number: 59750 Latitude: -10.5452 Longitude: 290.307 Instrument: VIS Captured: 2015-06-03 12:33 https://photojournal.jpl.nasa.gov/catalog/PIA21705

Melas Chasma - False Color

NASA Image and Video Library

2015-08-21

The THEMIS VIS camera contains 5 filters. The data from different filters can be combined in multiple ways to create a false color image. These false color images may reveal subtle variations of the surface not easily identified in a single band image. Today's false color image shows part of Melas Chasma. Orbit Number: 10289 Latitude: -9.9472 Longitude: 285.933 Instrument: VIS Captured: 2004-04-09 12:43 http://photojournal.jpl.nasa.gov/catalog/PIA19756

Confronting youth gangs in the intensive care unit.

PubMed

Akiyama, Cliff

2015-01-01

Youth gang violence has continued its upward trend nationwide. It was once thought that gangs convened only in selected areas, which left churches, schools, and hospitals as "neutral" territory. Unfortunately, this is a fallacy. The results of gang violence pour into hospitals and into intensive care units regularly. The media portrays California as having a gang violence problem; however, throughout the United States, gang violence has risen more than 35% in the past year. Youth gang violence continues to rise dramatically with more and more of our youth deciding to join gangs each day. Sadly, every state has gangs, and the problem is getting much worse in areas that would never have thought about gangs a year ago. These "new generation" of gang members is younger, much more violent, and staying in the gang longer. Gangs are not just an urban problem. Gang activity is a suburban and rural problem too. There are more than 25 500 gangs in the United States, with a total gang membership of 850 000. Ninety-four percent of gang members are male and 6% are female. The ethnic composition nationwide includes 47% Latino, 31% African American, 13% White, 7% Asian, and 2% "mixed," according to the Office of Juvenile Justice and Delinquency Prevention of the U.S. Department of Justice. As a result of the ongoing proliferation of youth street gangs in our communities, it is imperative that critical care nurses and others involved with the direct care become educated about how to identify gang members, their activities, and understand their motivations. Such education and knowledge will help provide solutions to families and the youth themselves, help eradicate the problem of gang violence, and keep health care professionals safe.

Drug use and treatment success among gang and non-gang members in El Salvador: a prospective cohort study

PubMed Central

2013-01-01

Background This article focuses on examining drug abuse treatment (DAT) in El Salvador highlighting gang vs. non-gang membership differences in drug use and treatment outcomes. Methods Cross-sectional and prospective cohort designs were employed to examine the study aims. The 19 centers that met the study’s inclusion criteria of one year or less in planned treatment offered varying treatment services: individual, group, family, and vocational therapy, dual diagnosis treatment, psychological testing, 12-step program, and outreach and re-entry aftercare. Most directors describe their treatment approach as “spiritual.” Data were collected from 625 patients, directors, and staff from the 19 centers at baseline, of which 34 patients were former gang members. Seventy-two percent (72%) of the former patients (448) were re-interviewed six-months after leaving treatment and 48% were randomly tested for drug use. Results Eighty-nine percent (89%) of the DAT patients at baseline were classified as heavy alcohol users and 40% were using illegal drugs, i.e., crack, marijuana, cocaine, tranquilizers, opiates, and amphetamines. There were large decreases after treatment in heavy alcohol and illegal drug use, crime, and gang related risk activities. Gang members reported illegal drug use, crime, and gang related risk activity more than non-gang members, yet only 5% of the study participants were gang members; further, positive change in treatment outcomes among gang members were the same or larger as compared to non-gang members. Conclusions Alcohol use is the drug of choice among DAT patients in El Salvador with gang member patients having used illegal drugs more than non-gang members. The study shows that DAT centers successfully reduced the use of illegal drugs and alcohol among gang and non-gang members. Although our study could not include a control group, we believe that the DAT treatment centers in El Salvador contributed to producing this treatment success among

Gang Membership and Pathways to Maladaptive Parenting

PubMed Central

Augustyn, Megan Bears; Thornberry, Terence P.; Krohn, Marvin D.

2014-01-01

A limited amount of research examines the short-term consequences of gang membership. Rarer, though, is the examination of more distal consequences of gang membership. This is unfortunate because it understates the true detrimental effect of gang membership across the life course, as well as the effects it may have on children of former gang members. Using data from the Rochester Youth Development Study, this work investigates the impact of gang membership in adolescence (ages 12-18) on a particularly problematic style of parenting, child maltreatment. Using discrete time survival analysis, this study finds that gang membership increases the likelihood of child maltreatment and this relationship is mediated by the more proximal outcomes of gang membership during adolescence, precocious transitions to adulthood. PMID:24883000

Finding Street Gang Members on Twitter.

PubMed

Balasuriya, Lakshika; Wijeratne, Sanjaya; Doran, Derek; Sheth, Amit

2016-08-01

Most street gang members use Twitter to intimidate others, to present outrageous images and statements to the world, and to share recent illegal activities. Their tweets may thus be useful to law enforcement agencies to discover clues about recent crimes or to anticipate ones that may occur. Finding these posts, however, requires a method to discover gang member Twitter profiles. This is a challenging task since gang members represent a very small population of the 320 million Twitter users. This paper studies the problem of automatically finding gang members on Twitter. It outlines a process to curate one of the largest sets of verifiable gang member profiles that have ever been studied. A review of these profiles establishes differences in the language, images, YouTube links, and emojis gang members use compared to the rest of the Twitter population. Features from this review are used to train a series of supervised classifiers. Our classifier achieves a promising F 1 score with a low false positive rate.

Venus - 3D Perspective View of Latona Corona and Dali Chasma

NASA Technical Reports Server (NTRS)

1992-01-01

This computer-generated perspective view of Latona Corona and Dali Chasma on Venus shows Magellan radar data superimposed on topography. The view is from the northeast and vertical exaggeration is 10 times. Exaggeration of relief is a common tool scientists use to detect relationships between structure (i.e. faults and fractures) and topography. Latona Corona, a circular feature approximately 1,000 kilometers (620 miles) in diameter whose eastern half is shown at the left of the image, has a relatively smooth, radar-bright raised rim. Bright lines or fractures within the corona appear to radiate away from its center toward the rim. The rest of the bright fractures in the area are associated with the relatively deep (approximately 3 kilometers or 1.9 miles) troughs of Dali Chasma. The Dali and Diana Chasma system consist of deep troughs that extend for 7,400 kilometers (4,588 miles) and are very distinct features on Venus. Those chasma connect the Ovda and Thetis highlands with the large volcanoes at Atla Regio and thus are considered to be the 'Scorpion Tail' of Aphrodite Terra. The broad, curving scarp resembles some of Earth's subduction zones where crustal plates are pushed over each other. The radar-bright surface at the highest elevation along the scarp is similar to surfaces in other elevated regions where some metallic mineral such as pyrite (fool's gold) may occur on the surface.

Highlights of the 2007 National Youth Gang Survey

ERIC Educational Resources Information Center

Egley, Jr., Arlen; O'Donnell, Christina E.

2009-01-01

This report presents findings from the 2007 National Youth Gang Survey. Data on the number of gangs, gang members, and gang-related homicides in larger cities, suburban counties, smaller cities, and rural counties are provided to accurately reflect youth gang activity in the United States. Based on survey results, it is estimated that nearly 3,550…

Gang Involvement and Membership among Homeless and Runaway Youth.

ERIC Educational Resources Information Center

Yoder, Kevin A.; Whitbeck, Les B.; Hoyt, Dan R.

2003-01-01

Assessed the extent of gang involvement among homeless and runaway youth, comparing gang members, gang-involved youth (not members), and non-gang youth on several dimensions. Interview data indicated that 15.4 percent of the youth were gang members and 32.2 percent were involved in gangs. These youth reported more family problems and school…

Gang homicides - five U.S. cities, 2003-2008.

PubMed

2012-01-27

Gang homicides account for a substantial proportion of homicides among youths in some U.S. cities; however, few surveillance systems collect data with the level of detail necessary to gang homicide prevention strategies. To compare characteristics of gang homicides with nongang homicides, CDC analyzed 2003-2008 data from the National Violent Death Reporting System (NVDRS) for five cities with high levels of gang homicide. This report describes the results of that analysis, which indicated that, consistent with similar previous research, a higher proportion of gang homicides than other homicides involved young adults and adolescents, racial and ethnic minorities, and males. Additionally, the proportion of gang homicides resulting from drug trade/use or with other crimes in progress was consistently low in the five cities, ranging from zero to 25%. Furthermore, this report found that gang homicides were more likely to occur with firearms and in public places, which suggests that gang homicides are quick, retaliatory reactions to ongoing gang-related conflict. These findings provide evidence for the need to prevent gang involvement early in adolescence and to increase youths' capacity to resolve conflict nonviolently.

Finding Street Gang Members on Twitter

PubMed Central

Balasuriya, Lakshika; Wijeratne, Sanjaya; Doran, Derek; Sheth, Amit

2017-01-01

Most street gang members use Twitter to intimidate others, to present outrageous images and statements to the world, and to share recent illegal activities. Their tweets may thus be useful to law enforcement agencies to discover clues about recent crimes or to anticipate ones that may occur. Finding these posts, however, requires a method to discover gang member Twitter profiles. This is a challenging task since gang members represent a very small population of the 320 million Twitter users. This paper studies the problem of automatically finding gang members on Twitter. It outlines a process to curate one of the largest sets of verifiable gang member profiles that have ever been studied. A review of these profiles establishes differences in the language, images, YouTube links, and emojis gang members use compared to the rest of the Twitter population. Features from this review are used to train a series of supervised classifiers. Our classifier achieves a promising F1 score with a low false positive rate. PMID:28713880

Automatic gang graffiti recognition and interpretation

NASA Astrophysics Data System (ADS)

Parra, Albert; Boutin, Mireille; Delp, Edward J.

2017-09-01

One of the roles of emergency first responders (e.g., police and fire departments) is to prevent and protect against events that can jeopardize the safety and well-being of a community. In the case of criminal gang activity, tools are needed for finding, documenting, and taking the necessary actions to mitigate the problem or issue. We describe an integrated mobile-based system capable of using location-based services, combined with image analysis, to track and analyze gang activity through the acquisition, indexing, and recognition of gang graffiti images. This approach uses image analysis methods for color recognition, image segmentation, and image retrieval and classification. A database of gang graffiti images is described that includes not only the images but also metadata related to the images, such as date and time, geoposition, gang, gang member, colors, and symbols. The user can then query the data in a useful manner. We have implemented these features both as applications for Android and iOS hand-held devices and as a web-based interface.

Gang Membership, Drug Selling, and Violence in Neighborhood Context

PubMed Central

Bellair, Paul E.; McNulty, Thomas L.

2014-01-01

A prominent perspective in the gang literature suggests that gang member involvement in drug selling does not necessarily increase violent behavior. In addition it is unclear from previous research whether neighborhood disadvantage strengthens that relationship. We address those issues by testing hypotheses regarding the confluence of neighborhood disadvantage, gang membership, drug selling, and violent behavior. A three-level hierarchical model is estimated from the first five waves of the 1997 National Longitudinal Survey of Youth, matched with block-group characteristics from the 2000 U.S. Census. Results indicate that (1) gang members who sell drugs are significantly more violent than gang members that don’t sell drugs and drug sellers that don’t belong to gangs; (2) drug sellers that don’t belong to gangs and gang members who don’t sell drugs engage in comparable levels of violence; and (3) an increase in neighborhood disadvantaged intensifies the effect of gang membership on violence, especially among gang members that sell drugs. PMID:25429188

Homicidal Events Among Mexican American Street Gangs

PubMed Central

Valdez, Avelardo; Cepeda, Alice; Kaplan, Charles

2010-01-01

This article examines the complexity of street gang homicides and focuses on situational factors that lead to gang members’ susceptibility to this violent behavior within the context of a disadvantaged minority community. This study is based on an analysis of 28 homicides involving Mexican American gang members. The absence of immigrant youth involvement in these types of violent crimes is discussed. Findings demonstrate how locally embedded social processes associated with specific gang types, ecology, drugs, circumstances, and motives unfold into homicidal events. These findings may contribute to the development of street-based social programs focused on gang mediation, dispute resolution, and crisis intervention. PMID:21218188

The process of desistance among core ex-gang members.

PubMed

Berger, Rony; Abu-Raiya, Hisham; Heineberg, Yotam; Zimbardo, Philip

2017-01-01

Research has established robust links between gang membership, delinquency, violence and victimization. Yet studies examining the process of gang desistance in general and that of core gang members in particular, are quite rare. The current study aims to identify factors associated with desistance of core gang members as well as describe the nature of the process that these "formers" have undergone. Thirty-nine core ex-gang members (80% males and 20% females) from the San Francisco Bay area and Los Angeles, with an average length of 11.6-years gang membership, were interviewed regarding their involvement in the gang and the desistance process. A systematic qualitative analysis based on grounded theory methodology was mainly utilized. We found that the decision to leave the gang is a result of a combination of push (e.g., personal and vicarious victimization, burnout of gang lifestyle, disillusionment by the gang) and pull (e.g., parenthood, family responsibilities, religious and cultural awakening) factors that evolved over time. Push factors were more dominant in this domain. We also found that while male core ex-gang members tended to leave the gang more frequently because of push factors, female ex-gang members were more inclined to desist due to pull factors. Our analysis also showed that core gang members shared a general pattern of the desistance process comprising of the following 5 stages: triggering, contemplation, exploration, exiting and maintenance. Based on these results, we outlined stage-specific recommendations for agents of societal change to help in facilitating the desistance of core gang members. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

The transitional depositional environment and sequence stratigraphy of Chasma Boreale

NASA Astrophysics Data System (ADS)

Brothers, S. C.; Kocurek, G.

2018-07-01

The depositional system within Chasma Boreale is unique in that it contains active aeolian environments, expressed as dune fields, and active cryosphere environments, present as layered ice deposits, as well as environments that transition between these. This work presents a new analysis of the Chasma Boreale sediment system that creates an interpretative framework addressing: (a) controls on the balance between aeolian and cryospheric processes in the modern depositional system, (b) the stratigraphic architecture of related sedimentary deposits, and (c) processes of sediment accumulation and preservation. Images from Context Camera (CTX; 6 m/pixel) are used to classify and map sedimentary environments, surfaces, and deposits on the reentrant floor, to refine the established geologic map of the reentrant, and to infer the stratigraphic record of the accumulation from Chasma Boreale's depositional system. A spectrum of sedimentary environments occurring between those dominated by aeolian and by cryospheric processes are identified. Through time, the boundaries of these sedimentary environments have shifted, resulting in complex lateral changes in the configuration of sedimentary environments on the reentrant's floor. Vertically, the stratigraphic record is characterized by the punctuation of sandy aeolian deposits by icy surfaces that indicate episodes of ice growth that preserve underlying deposits, resulting in accumulation. Stabilized icy surfaces occur at multiple vertical (temporal) scales and lateral extents, suggesting the influence of both regional climate change due to allogenic forcing, as well as autogenic dynamics within the transitional system. These observations demonstrate that the Chasma Boreale accumulation can be interpreted in an aeolian sequence stratigraphic framework. This work contributes the first detailed description of the processes forming polar aeolian sequences, with an emphasis on the competing and complementary dynamics between aeolian

Gangs in Schools. Breaking Up Is Hard To Do.

ERIC Educational Resources Information Center

National School Safety Center, Malibu, CA.

This handbook offers the latest information on gangs and practical advice on preventing or reducing gang encroachment in schools. Gang experts believe that establishing codes of conduct, diligent awareness of gang rivalries, prevention courses, and community and parental involvement can make an impact in keeping gangs away from campus. Chapter 1,…

Evidence for triple-junction rifting focussed on local magmatic centres along Parga Chasma, Venus

NASA Astrophysics Data System (ADS)

Graff, J. R.; Ernst, R. E.; Samson, C.

2018-05-01

Parga Chasma is a discontinuous rift system marking the southern boundary of the Beta-Atla-Themis (BAT) region on Venus. Along a 1500 km section of Parga Chasma, detailed mapping of Magellan Synthetic Aperture Radar images has revealed 5 coronae, 11 local rift zones distinct from a regional extension pattern, and 47 graben-fissure systems with radiating (28), linear (12) and circumferential (7) geometries. The magmatic centres of these graben-fissure systems typically coincide with coronae or large volcanoes, although a few lack any central magmatic or tectonic feature (i.e. are cryptic). Some of the magmatic centres are interpreted as the foci of triple-junction rifting that form the 11 local rift zones. Cross-cutting relationships between graben-fissure systems and local rift faults reveal synchronous formation, implying a genetic association. Additionally, cross-cutting relationships show that local rifting events postdate the regional extension along Parga Chasma, further indicating multiple stages of rifting. Evidence for multiple centres of younger magmatism and local rifting against a background of regional extension provides an explanation for the discontinuous morphology of Parga Chasma. Examination of the Atlantic Rift System (prior to ocean opening) on Earth provides an analogue to the rift morphologies observed on Venus.

Geology of the V28 Quadrangle: Hecate Chasma, Venus

NASA Technical Reports Server (NTRS)

Stofan, E. R.; Guest, J. E.; Brian, A. W.

2000-01-01

The Hecate Chasma Quadrangle (V28), mapped at 1:5,000,000 scale, extends from 0-25 N and 240-270 Longitude. The quadrangle has thirteen impact craters, several large volcanoes, many coronae, three chasmata, and northern Hinemoa Planitia.

Melas Chasma in IR Color

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

Released August 11, 2004 This image shows two representations of the same infra-red image over Melas Chasma. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations.

There is a distinct purple/blue layer present in the northern wall of the Chasma. Although this layer likely has a composition different than the surrounding areas, it is difficult to interpret its specific composition due to the high variability of sunlit and shaded surfaces in this area, which cause a wide range of temperatures to be present within each pixel of the image. It is possible that this layer has a unique composition due to differences in the volcanic or sedimentary environment at the time that the rock formed, or it could be a layer of magma injected between two previously existing rock layers. Another possibility is that the wall is mostly covered by dust and debris, and this portion contains the only exposed bedrock. The light blue colors present in many other areas of the Chasma are due to water ice clouds.

Image information: IR instrument. Latitude -8.9, Longitude 282 East (78 West). 100 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey

The Minerals of Candor Chasma

NASA Technical Reports Server (NTRS)

2008-01-01

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) took this image of sulfate- and pyroxene-containing deposits in the Candor Chasma region of Mars at 0747 UTC (2:47 a.m. EST) on December 2, 2006, near 6.7 degrees south latitude, 75.8 degrees west longitude. The image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 40 meters (132 feet) across. The image is about 10 kilometers (6.2 miles) wide at its narrowest point.

Candor Chasma is a deep, elongated, steep-sided depression some 813 kilometers (505 miles) long. It is one of two large chasmata that make up the northern end of the Valles Marineris system.

The top panel in the montage above illustrates the location of CRISM data on a mosaic taken by the Mars Odyssey spacecraft's Thermal Emission Imaging System (THEMIS). CRISM data cover an area centered on the southwestern part of Candor Chasma, where highland crust was depressed by faulting and buried by a kilometers-thick stack of layered deposits.

The bottom two images are views of CRISM data. The lower left image is an infrared false color image, while at lower right is a spectral image that illustrates the distribution of sulfates in the layered deposits, the olivine and pyroxene that make up the faulted highland crust, and high-calcium pyroxene in the highland crust.

The northern part of CRISM's data swath covers interior deposits formed after the canyon floor was faulted and depressed. This lighter region in the infrared image at lower left exhibits the spectral signatures of sulfates (blues) in the CRISM spectral image at lower right. The southern end of CRISM's data reveals volcanic minerals (pyroxene and olivine) that make up the older, underlying highland crust. The strongest signature comes from the common diopside-hedenbergite series of pyroxenes a group of silicate materials rich in iron, magnesium, and calcium.

CRISM is one of six science instruments on NASA's Mars

Gang youth, substance use, and drug normalization

PubMed Central

Sanders, Bill

2014-01-01

Gang membership is an indicator of chronic substance use.1 Evidence from North America and Europe indicates that gang youth, in comparison to their non-gang peers, are more likely to report alcohol and illicit drug use (Bendixen, Endresen, & Olweus, 2006; Gatti, Tremblay, Vitaro, & McDuff, 2005; Gordon, et al., 2004; Hall, Thornberry, & Lizotte, 2006; Sharp, Aldridge, & Medina, 2006). Qualitative studies focusing specifically on gang members have also noted high frequencies of lifetime rates of use for a variety of illegal substances (De La Rosa, Rugh, & Rice, 2006; Hagedorn, Torres, & Giglio, 1998; Hunt, Jo-Laidler, & Evans, 2002; Mata et al., 2002; Valdez, Kaplan, & Cepeda, 2006). Gang youth, however, have differential attitudes towards the use of various illegal drugs. Marijuana, for instance, has remained a staple within gang culture, but the use of other drugs has been heavily stigmatized, especially heroin, methamphetamine, and crack cocaine (MacKenzie, Hunt, & Joe-Laidler, 2005; Moore, 1978; Taylor, 1990; Waldorf, 1993). Perspectives with good explanatory power should be flexible enough to elucidate these distinctions regarding illicit substance use patterns and preferences. PMID:25221432

Coprates Chasma Landslide

NASA Technical Reports Server (NTRS)

2002-01-01

[figure removed for brevity, see original site]

Coprates Chasma comprises the central portion of the Valles Marineris canyon system complex. This image of the southern wall of Coprates Chasma contains a landslide deposit with dunes over portions of slide. Landslides have very characteristic morphologies on Earth, which they also display on Mars. These morphologies include a distinctive escarpment at the uppermost part of the landslide--called a head scarp (seen at the bottom of this image), a down-dropped block of material below that escarpment that dropped almost vertically, and a deposit of debris that moved away from the escarpment at high speed. In this example, the wall rock displayed in the upper part of the cliff contains spurs and chutes created by differing amounts of erosion. The actual landslide deposit is delineated by its fan-shape and lobate margins. The dunes subsequently marched upon the landslide deposit.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a

Gang Activity on Campus: A Crisis Response Case Study

ERIC Educational Resources Information Center

Shaw, Mahauganee; Meaney, Sarah

2015-01-01

This case study challenges readers to consider a contemporary issue for campus threat assessment and emergency preparedness: gang presence on college campuses. A body of research examining the presence of gangs and gang activity on college campuses has developed, revealing that gangs pose a viable threat for institutions of higher education. The…

Possible Juventae Chasma subice volcanic eruptions and Maja Valles ice outburst floods on Mars: Implications of Mars Global surveyor crater densities, geomorphology, and topography

USGS Publications Warehouse

Chapman, M.G.; Gudmundsson, M.T.; Russell, A.J.; Hare, T.M.

2003-01-01

This article discusses image, topographic, and spectral data from the Mars Global Surveyor (MGS) mission that provide new information concerning the surface age, geomorphology, and topography of the Juventae Chasma/Maja Valles system. Our study utilizes data from two instruments on board MGS: images from the Mars Orbiter Camera (MOC) and topography from the Mars Orbiter Laser Altimeter (MOLA). Within Maja Valles we can now observe depositional bars with megaripples that unequivocally show catastrophic floods occurred in the channel. Viking impact crater densities indicated the chasma and channel floor areas were all one age (late Hesperian to Amazonian); however, MOC data indicate a marked difference in densities of small craters between Juventae Chasma, Maja Valles, and the channel debouchment area in Chryse Planitia basin. Although other processes may contribute to crater variability, young resurfacing events in the chasma and episodes of recent erosion at Maja Valles channel head may possibly account for the disparate crater densities along the chasma/channel system. Relatively young volcanic eruptions may have contributed to resurfacing; as in Juventae Chasma, a small possible volcanic cone of young dark material is observed. MOC data also indicate previously unknown interior layered deposit mounds in the chasma that indicate at least two periods of mound formation. Finally, MOLA topography shows that the entire floor of the chasma lies at the same elevation as the channel debouchment area in Chryse basin, resulting in a 3-km-high barrier to water flow out of the chasma. Blocked ponded water would rapidly freeze in the current (and likely past) climate of Mars. For catastrophic flow to occur in Maja Valles, some process is required to melt ice and induce floods out of the chasma. We suggest subice volcanic eruption and calculate estimates of water discharges and volumes that these eruptions might have produced.

Insurgency in the Hood: Understanding Insurgencies Through Urban Gangs

DTIC Science & Technology

2006-06-01

bond between the members of the social network . 50 Wiktorowitz, 10. 51 Gang membership, Delinquent Peers and...38 3. Control and Selective Incentives .............39 a. Social Network Theory ...................41 b. Physical...the gang makes them feel like they are part of a family.”26 The gang also provides peers for socialization . The gang can provide identity

Interior Layered Deposits on Mars: Insights from elevation, image- and spectral data of Ganges Mensa

NASA Astrophysics Data System (ADS)

Sowe, M.; Roach, L. H.; Hauber, E.; Jaumann, R.; Mustard, J. L.; Neukum, G.

2008-09-01

sulfate (PHS) features are observed in the light-toned material while the dark dunes on top and in grooves show clinopyroxene (HCP). The mineralogy might correlate with the steepness of the slopes observed by [8,10] for kieserite being exposed in steeper parts and polyhydrated sulfates in less steep parts. As the ILD is composed of alternating steep and less steep parts, less steep parts may possibly exhibit polyhydrated sulfates that are covered by windblown material. We observe a higher thermal inertia in the lower, fresh eroded kieserite unit (400-600 SI) than in the upper unit that shows polyhydrated sulfate features (300- 500 SI) which is not coincident to observations in West Candor Chasma ILD [11] but may be due to weak PHS signal or hydration state of PHS. The same is observed comparing kieserite exposed on steep exposures and PHS [12] in Capri Chasma. ILDs observed in other regions ILDs have various morphologies. They often appear as mounds or hills. Massive cap rock at their top and layering in lower parts is also very common. Material enclosing chaotic structures, terrace-like appearances, and knobs are visible. Varying surfaces (knobby, rough, fractured, grooved, cap rock) are widespread as well as talus exhibited on steep slopes. Yardangs and flutes on their surface as well as dunes located in surface fractures indicate that the material is highly affected by wind erosion and therefore weakly consolidated. The contact between ILD and chaotic terrain often is covered by dusty and/or fine-grained material, but few MOC-images [9] show the stratigraphic position of ILDs superposing chaotic terrain, and indicating a younger age. Layering is observed at different elevations at MOCscale reaching from -4.6 km up to -1 km, but mostly between -4.5 km up to -3 km and is absent in upper parts that are mostly cap rock. The vertical thickness of layered material is high in Ganges Mensa and low in other regions of Ganges or the chaotic terrains, e.g. Arsinoes. We

Gangs and a global sociological imagination

PubMed Central

Fraser, Alistair; Hagedorn, John M

2016-01-01

Across the globe, the phenomenon of youth gangs has become an important and sensitive public issue. In this context, an increasing level of research attention has focused on the development of universalized definitions of gangs in a global context. In this article, we argue that this search for similarity has resulted in a failure to recognize and understand difference. Drawing on an alternative methodology we call a ‘global exchange’, this article suggests three concepts—homologies of habitus, vectors of difference and transnational reflexivity—that seek to re-engage the sociological imagination in the study of gangs and globalization. PMID:29503595

Gangs and a global sociological imagination.

PubMed

Fraser, Alistair; Hagedorn, John M

2018-02-01

Across the globe, the phenomenon of youth gangs has become an important and sensitive public issue. In this context, an increasing level of research attention has focused on the development of universalized definitions of gangs in a global context. In this article, we argue that this search for similarity has resulted in a failure to recognize and understand difference. Drawing on an alternative methodology we call a 'global exchange', this article suggests three concepts-homologies of habitus, vectors of difference and transnational reflexivity-that seek to re-engage the sociological imagination in the study of gangs and globalization.

The Impact of Gang Formation on Local Patterns of Crime

ERIC Educational Resources Information Center

Tita, George; Ridgeway, Greg

2007-01-01

Research has demonstrated that even after controlling for individual level attributes, individuals who join gangs commit more crimes than do nongang members. Furthermore, the offending level of gang members is higher when they report being active members of the gang. Therefore, gang membership clearly facilitates offending above and beyond…

Gang Prevention: An Overview of Research and Programs. Juvenile Justice Bulletin

ERIC Educational Resources Information Center

Howell, James C.

2010-01-01

This bulletin presents research on why youth join gangs and how a community can build gang prevention and intervention services. The author summarizes recent literature on gang formation and identifies promising and effective programs for gang prevention. The following are some key findings: (1) Youth join gangs for protection, enjoyment, respect,…

Potential MER Landing Site in Melas Chasma

NASA Technical Reports Server (NTRS)

Weitz, C. M.; Parker, Timothy J.; Anderson, F. Scott

2001-01-01

We have selected one area in Valles Marineris as a potential landing site for the Mars Exploration Rover (MER) mission. After 30 years of analyses, the formation of the Valles Marineris system of troughs and its associated deposits still remains an enigma. Understanding all aspects of the Valles Marineris would significantly contribute to deciphering the internal and external history of Mars. A landing site within Melas Chasma could provide insight into both the formation of Valles Marineris and the composition and origin of the interior layered deposits (ILDs). The ILDs have been proposed as: (1) sedimentary deposits formed in lakes mass wasted material from the walls; (3) remnants of the wall rock; (4) carbonate deposits; (5) aeolian deposits; and (6) volcanic. More recently, Malin and Edgett suggest that the fine-scale, rhythmic layering seen in the interior deposits, as well as other layered deposits in craters, supports a sedimentary origin. Because an understanding of the formation of Valles Marineris and its interior deposits is so important to deciphering the history of Mars, we have proposed a landing site for the MER mission on an exposure of interior deposits in western Melas Chasma. Either MER-A and MER-B could land at this same location.

Predicting early adolescent gang involvement from middle school adaptation.

PubMed

Dishion, Thomas J; Nelson, Sarah E; Yasui, Miwa

2005-03-01

This study examined the role of adaptation in the first year of middle school (Grade 6, age 11) to affiliation with gangs by the last year of middle school (Grade 8, age 13). The sample consisted of 714 European American (EA) and African American (AA) boys and girls. Specifically, academic grades, reports of antisocial behavior, and peer relations in 6th grade were used to predict multiple measures of gang involvement by 8th grade. The multiple measures of gang involvement included self-, peer, teacher, and counselor reports. Unexpectedly, self-report measures of gang involvement did not correlate highly with peer and school staff reports. The results, however, were similar for other and self-report measures of gang involvement. Mean level analyses revealed statistically reliable differences in 8th-grade gang involvement as a function of the youth gender and ethnicity. Structural equation prediction models revealed that peer nominations of rejection, acceptance, academic failure, and antisocial behavior were predictive of gang involvement for most youth. These findings suggest that the youth level of problem behavior and the school ecology (e.g., peer rejection, school failure) require attention in the design of interventions to prevent the formation of gangs among high-risk young adolescents.

Working Together To Erase Gangs in Our Schools.

ERIC Educational Resources Information Center

National Consortium on Alternatives for Youth at Risk, Inc., Sarasota, FL.

A common misconception about gangs is that they resemble past images of motorcycle riders. Society is now faced with what are called "hybrid" gangs whose members are usually 14 to 16 years of age, who dress conservatively, who display subtle gang identifiers, and who are motivated by a combination of profit and poor family life. This…

Gangs, My Town and the Nation.

ERIC Educational Resources Information Center

Randolph, Norman; Erickson, Edsel

The nature of youth gangs is explored, with suggestions for gang prevention and intervention. The emphasis is on organizing citizens, especially at the neighborhood level, to affect all community institutions. Suggestions are offered for citizens' groups to look at critical areas in schooling, incarceration, law enforcement, community programs,…

Extending Social Learning Theory to Explain Victimization Among Gang and Ex-Gang Offenders.

PubMed

Gagnon, Analisa

2018-03-01

This study is among the first to extend and test social learning theory's ability to understand property and violent victimization. It specifically tests whether aspects of definitions, differential reinforcement, and differential association/modeling can explain the three types of victimization of gang members: actual experience, perception of likelihood, and fear. The sample consists of over 300 male and female gang members incarcerated in jails throughout Florida. The results show that all three types of victimization can be explained by the three aspects of social learning theory.

The Youth Gangs, Drugs, and Violence Connection. Juvenile Justice Bulletin.

ERIC Educational Resources Information Center

Howell, James C.; Decker, Scott H.

This bulletin addresses questions about the interrelatedness of youth gangs, drugs, and violent crime, discussing whether drug trafficking is a main cause of violence in youth gangs or only a correlate, and noting whether there are other important sources of gang violence. Section 1 presents a historical overview of gang drug use and trafficking,…

Teaching Responsibility to Gang-Affiliated Youths

ERIC Educational Resources Information Center

Buckle, Michael E.; Walsh, David S.

2013-01-01

Teaching youths who affiliate with a gang can be a daunting task. Risk factors for gang membership often compound across life domains and affect pro-social connectedness, cause feelings of marginalization, and hinder life-skill development. Sports and physical activities that are structured within a positive youth-development framework provide an…

Neighborhood Variation in Gang Member Concentrations

ERIC Educational Resources Information Center

Katz, Charles M.; Schnebly, Stephen M.

2011-01-01

This study examines the relationship between neighborhood structure, violent crime, and concentrations of gang members at the neighborhood level. We rely on official police gang list data, police crime data, and two waves of decennial census data characterizing the socioeconomic and demographic conditions of 93 neighborhoods in Mesa, Arizona.…

Female Gang Members: A Profile of Aggression and Victimization.

ERIC Educational Resources Information Center

Molidor, Christian E.

1996-01-01

Most gang membership research studies males; few examine the etiology of female gang membership. Presents themes of female gang membership gathered from interviews with 15 young women. Examines demographic material, family structure, initiation rites, and criminal behaviors. Explores implications for social work practice and research. (FC)

Hidden behind the gunfire: young women's experiences of gang-related violence.

PubMed

Medina, Juanjo; Ralphs, Robert; Aldridge, Judith

2012-06-01

This article uses data from a 3-year multisite ethnographic research study of gangs within an English city, to explore the different ways that "gang culture" shapes the victimization experiences and everyday lives of (young) women. Victims of lethal gang violence in Research City are almost exclusively young men, rendering invisible the ways in which gangs have an impact on the lives of women living in neighborhoods with a gang presence. The article also discusses how the adoption of a transdisciplinary approach could be useful in developing a holistic picture of the impact of gang-related violence on the lives of women.

Gang warfare: the medical repercussions.

PubMed

Song, D H; Naude, G P; Gilmore, D A; Bongard, F

1996-05-01

Gang related violence in Los Angeles County has increased, with homicides increasing from 205 in 1982 to 803 in 1992. This study examines the medical and financial consequences of such violence on a level I trauma center. Of 856 gunshot injuries over a 29-month period, 272 were gang related. There were 55 pediatric and 217 adult patients. Eighty-nine percent were male and 11% were female. Trauma Score averaged 14.7 +/- 3.1, Glasgow Coma Scale average score was 13.7 +/- 3.4, and the mean Injury Severity Score was 10.8 +/- 14. Twenty-two percent of the gunshots were to the head and neck, 20% to the chest, 20% to the abdomen, 6% had a peripheral vascular injury, and 33% sustained an extremity musculoskeletal injury. Emergency surgery was performed on 43%, including laparotomy 58 (49%), craniotomy 16 (13%), laparoscopy 14 (12%), vascular procedures 10 (8%), orthopedic procedures 6 (5%), head and neck endoscopies 4 (3%), thoracotomies 2 (2%), and 10 (8%) unspecified. There were 25 deaths (9%), primarily caused by head injuries and exsanguinating hemorrhage. Eighty-six percent entered the hospital during the hours of minimal staffing that preempted the use of facilities for other emergent patients. Charges totaled $4,828,828 (emergency room, surgical procedures, intensive care, and surgical ward stay) which equated to $5,550 per patient per day. Fifty-eight percent had no third party reimbursement, 22% had Medi-Cal, and 20% had medical insurance. Because of dismal reimbursement rates, the costs of gang violence are passed on to the tax payer. The cost of gang related violence cannot be derived from hospital charges only, because death, disability, and pain are not entered into the calculation. Education, increased social programs, and strict criminal justice laws and enforcement may decrease gang related violence and the drain it has on financial and medical resources.

2000 Survey of Youth Gangs in Indian Country. NYGC Fact Sheet.

ERIC Educational Resources Information Center

Major, Aline K.; Egley, Arlen, Jr.

In 2001, the National Youth Gang Center conducted a survey of youth gangs in Indian country. Three hundred of the 577 federally recognized tribal communities responded to the survey. Twenty-three percent of Indian communities reported active youth gangs during 2000. The extent of the gang problem varied considerably among communities, with many…

Ganges River Delta

NASA Technical Reports Server (NTRS)

2002-01-01

The Ganges River forms an extensive delta where it empties into the Bay of Bengal. The delta is largely covered with a swamp forest known as the Sunderbans, which is home to the Royal Bengal Tiger. It is also home to most of Bangladesh, one of the world's most densely populated countries. Roughly 120 million people live on the Ganges Delta under threat of repeated catastrophic floods due to heavy runoff of meltwater from the Himalayas, and due to the intense rainfall during the monsoon season. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on February 28, 2000. This is a false-color composite image made using green, infrared, and blue wavelengths. Image provided by the USGS EROS Data Center Satellite Systems Branch

U.S. Juvenile Arrests: Gang Membership, Social Class, and Labeling Effects

ERIC Educational Resources Information Center

Tapia, Mike

2011-01-01

This study addresses the link between gang membership and arrest frequency, exploring the Gang x Socioeconomic status interaction on those arrests. Notoriously poor, delinquent, and often well-known to police, America's gang youth should have very high odds of arrest. Yet it is unclear whether mere membership in a gang increases the risk of arrest…

Integrating seepage heterogeneity with the use of ganged seepage meters

USGS Publications Warehouse

Rosenberry, D.O.

2005-01-01

The usefulness of standard half-barrel seepage meters for measurement of fluxes between groundwater, and surface water is limited by the small bed area that each measurement represents and the relatively large associated labor costs. Standard half-barrel cylinders were ganged together to allow one measurement of the summed seepage through all of the meters, reducing labor cost and increasing the representative area of measurement. Comparisons of ganged versus individual-meter measurements at two lakes, under both inseepage and outseepage conditions, indicate little loss of efficiency resulting from routing seepage water through the ganging system. Differences between summed and ganged seepage rates were not significant for all but the fastest rates of seepage. At flow rates greater than about 250 mL min-1, ganged values were as low as 80% of summed values. Ganged-meter head losses also were calculated to determine their significance relative to hydraulic-head gradients measured at the field sites. The calculated reduction in hydraulic gradient beneath the seepage meters was significant only for the largest measured seepage rates. A calibration tank was used to determine single-meter and ganged-meter efficiencies compared to known seepage rates. Single-cylinder seepage meters required an average correction factor of 1.05 to convert measured to actual values, whereas the ganged measurements made in the tank required a larger correction factor of 1.14. Although manual measurements were used in these tests, the concept of ganging seepage cylinders also would be useful when used in conjunction with automated flowmeters. ?? 2005, by the American Society of Limnology and Oceanography, Inc.

Juventae Chasma and Maja Valles, Mars: Further Evidence for Multiple Flooding Events

NASA Astrophysics Data System (ADS)

Gross, C.; Wendt, L.; Dumke, A.; Neukum, G.

2009-04-01

Introduction: In this study we investigate the age relationship of Juventae Chasma to the adjacent Maja Valles in order to gain a feasible explanation for the formation and evolution of rhythmic light-toned layered deposits (LLD). In this first step, we use impact crater size-frequency distributions for dating the planetary surface in the regions of interest. Juventae Chasma is located at the northern side of the Valles Marineris and stretches for approximately 150 km east-west and 250 km north-south. The basin floor shows a depth of 5 km and more below the surrounding surface. To the north lies the adjacent Maja Valles, a 50 km to 150 km wide channel extending for 1600 km northward and discharging into the Chryse Planitia plains. Various investigations of several authors have been carried out on this subject in the past, but the formation of the LLD in Juventae Chasma is still poorly understood. The formation theories range from a volcanic origin [1], lake deposits, delta deposits [2] to spring deposits [3]. A very different hypothesis for the formation of the sulfates is deposition from airfall. This could happen as dry deposition from the atmosphere or in co-precipitation with icy materials such as snow crystals or dust particles. This phenomenon is observed at the poles of Mars, where rhythmic layerings occur showing high similarities to the sulfate deposits in Juventae Chasma. The light-toned materials in the chasma show a spectral signature indicative of kieserite in the outcrops A, C and D and in the lower part of B, whereas the upper part of B was described as gypsum [4]. Wendt et al. [5] identified different mineral assemblages in the cap rock of mount B, using the CRISM instrument and the Multiple-Endmember Linear Spectral Unmixing Model (MELSUM). HRSC DTM: The Digital Terrain Model (DTM ) mosaic (see Fig. 1) was derived from 11 HRSC orbits at approximately -7° S to 8° N and 295° to 301° E with a ground resolution of 100 m per pixel and an ortho

Highlights of the 2011 National Youth Gang Survey

MedlinePlus

... Administrator Highlights of the 2011 National Youth Gang Survey Arlen Egley, Jr., and James C. Howell This ... 2010 to 1,824 in 2011. About the Survey Since 1996, the National Gang Center, through the ...

Convention versus deviance: moral agency in adolescent gang members’ decision making

PubMed Central

Dickson-Gomez, Julia; Pacella, Maria; Broaddus, Michelle; Quinn, Katherine; Galletly, Carol; Rivas, Justin

2017-01-01

Background Adolescent gang members are a source of concern due to their involvement in criminal activity, violence, substance use and high-risk sexual behaviors. Adolescent gang theories hypothesize that social institutions, including the family and school, fail to meet the needs of adolescents who therefore feel less attachment to these institutions and find an unconventional institution (i.e. the gang) to meet these needs through the gang. Objectives In this paper we will examine the extent to which social disorganization and social control theories, in particular the rejection of conventional norms and aspirations, match adolescents subjective reasons for their decisions and their future aspirations. Methods Between 2012 and 2013, we conducted in-depth interviews with 58 gang members between the ages of 14 to 19. Interviews were coded for key themes using the constant comparison method. Results Social disorganization and social control theories have both value and limitations in explaining reasons why adolescents join gangs and engage in criminal behaviors. Participants saw many of their aspirations blocked by negative school experiences and limited economic opportunities. Gangs provided a social organization in which to sell drugs. However, gang members did not reject conventional norms and aspirations. Rather, they view themselves as making decisions to survive in the present while recognizing that these strategies will not continue to work in the future. Conclusions: Gang members value education and aspire to obtain legal employment. Thus, interventions to help adolescent gang members with the immediate financial pressures that lead them to sell drugs may be particularly effective. PMID:28010161

MEXICAN AMERICAN YOUTH AND ADULT PRISON GANGS IN A CHANGING HEROIN MARKET

PubMed Central

Valdez, Avelardo

2010-01-01

This article focuses on the interaction between the larger community’s drug markets and youth and adult prison gangs, and the process that leads to specific adverse consequences both to the youth gangs as organizations, and to individual members. Described is the emergence of a restructured heroin market dominated by an adult prison gang. A major consequence of this was the increasing use of heroin among Mexican American gang members and their transformation from autonomous youth gangs to extensions of the adult prison gangs or their demise. Data was collected from 160 members of 26 Mexican American youth gangs and key informants in San Antonio. Findings focus on organizational rules, drug market transformations, consequences on members, and the impact of heroin on the gang’s organization. Discussed is how the dominance of prison gangs is related to the increased incarceration and recidivism rates of Mexican Americans and declining economic opportunities for urban minorities. PMID:21614143

Geology of a Proposed MER Landing Site in Western Melas Chasma

NASA Technical Reports Server (NTRS)

Weitz, C. M.; Parker, T. J.; Anderson, F. S.; Grant, J. A.

2002-01-01

A proposed landing site for the Mars Exploration Rover (MER) has been identified in western Melas Chasma. The landing ellipse contains a blocky, bright deposit which we propose formed as a landslide, perhaps beneath a former lake. Additional information is contained in the original extended abstract.

Melas Materials

NASA Image and Video Library

2006-05-01

This MOC image shows dark sand dunes superposed on layered, light-toned outcrops -- interpreted to be sedimentary rocks -- in Melas Chasma. Melas Chasma is part of the enormous Valles Marineris trough system

Evidences of early aqueous Mars: Implications on the origin of branched valleys in the Ius Chasma, Mars

NASA Astrophysics Data System (ADS)

Martha, Tapas R.; Jain, Nirmala; Vamshi, Gasiganti T.; Vinod Kumar, K.

2017-11-01

This study shows results of morphological and spectroscopic analyses of Ius Chasma and its southern branched valleys using Orbiter datasets such as Mars Reconnaissance Orbiter (MRO)-Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), High Resolution Imaging Science Experiment (MRO-HiRISE) and digital terrain model (HRSC-DTM). Result of the spectral analysis reveals presence of hydrated minerals such as opal, nontronite and vermiculite in the floor and wall rock areas Ius Chasma indicating alteration of parent rock in an water rich environment of early Mars. Topographic gradient and morphological evidences such as V-shaped valleys with theatre shaped stubby channels, dendritic drainage and river piracy indicate that these valleys were initially developed by surface runoff due to episodic floods and further expanded due to groundwater sapping controlled by faults and fractures. Minerals formed by aqueous alteration during valley formation and their intricate association with different morphological domains suggest that surface runoff played a key role in the development of branched valleys south of Ius Chasma on Mars.

Layered Outcrops of Far West Candor Chasma

NASA Technical Reports Server (NTRS)

2000-01-01

[figure removed for brevity, see original site]

Images from Mariner 9 in 1972 revealed that some of the mesas and mounds found within the chasms of the martian 'Grand Canyon'--the Valles Marineris--have layers in them. Speculations as to the origin of these interior layered materials ranged from volcanic ash deposits to sediments laid down in lakes that could have partially filled the Vallis Marineris troughs, much as lakes now occupy portions of the rift valleys of eastern Africa. The proposal that the Valles Marineris once hosted deep martian lakes led to additional speculation as to the prospects for finding fossil evidence of martian life.

Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images have ten or more times better resolution than the Mariner 9 and Viking orbiter images taken in the 1970s. MOC images have indeed confirmed the presence of layered outcrops within the Valles Marineris. They have also shown places previously not suspected to have layered rock, and they have shown that these materials might not have formed in the Valles Marineris, but were instead deposited in craters that were subsequently buried long before the chasms opened up (see discussion below). The layered rock is now visible because of faulting and erosion.

The high resolution picture shown here (B, above right) was the first image received by MOC scientists that began to hint at a larger story of layered sedimentary rock on Mars. The picture shows a 1.5 km by 2.9 km (0.9 mi by 1.8 mi) area in far southwestern Candor Chasma (A, above left) that was--based on Mariner 9 and Viking orbiter images--not previously expected to exhibit layers. The MOC image reveals that the floor of western Candor Chasma at this location is indeed layered. What is most striking about the picture is the large number and uniformity of the layers, or beds. There are over 100 beds in this area, and each has about the same thickness (estimated to be about 10 meters (11 yards) thick). Each layer

Long-term consequences of adolescent gang membership for adult functioning.

PubMed

Gilman, Amanda B; Hill, Karl G; Hawkins, J David

2014-05-01

We examined the possible public health consequences of adolescent gang membership for adult functioning. Data were drawn from the Seattle Social Development Project, a longitudinal study focusing on the development of positive and problem outcomes. Using propensity score matching and logistic regression analyses, we assessed the effects of adolescent gang membership on illegal behavior, educational and occupational attainment, and physical and mental health at the ages of 27, 30, and 33 years. In comparison with their nongang peers, who had been matched on 23 confounding risk variables known to be related to selection into gang membership, those who had joined a gang in adolescence had poorer outcomes in multiple areas of adult functioning, including higher rates of self-reported crime, receipt of illegal income, incarceration, drug abuse or dependence, poor general health, and welfare receipt and lower rates of high school graduation. The finding that adolescent gang membership has significant consequences in adulthood beyond criminal behavior indicates the public health importance of the development of effective gang prevention programs.

Layers and a Dust Devil in Melas Chasma

NASA Technical Reports Server (NTRS)

2000-01-01

One of the earliest observations made by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) was that the upper crust of the planet appears to be layered to considerable depth. This was especially apparent, early in the mission, in the walls of the Valles Marineris chasms. However, layered mesas and mounds within the Valles Marineris troughs were recognized all the way back in 1972 with Mariner 9 images. The MOC image presented here shows many tens of layers of several meters (yards) thickness in the walls of a mesa in southern Melas Chasma in Valles Marineris. Erosion by mass wasting--landslides--has exposed these layers and created the dark fan-shaped deposits seen near the middle of the image. The floor of Melas Chasma is dark and covered with many parallel ridges and grooves (lower 1/3 of image). In the lower left corner of the picture, a bright, circular dust devil can be seen casting a columnar shadow toward the left. This image, illuminated by sunlight from the right/lower right, covers an area 3 kilometers (1.9 miles) wide and 8.2 kilometers (5.1 miles) long. The scene is located near 10.1oS, 74.4oW and was acquired on July 11, 1999. North is toward the lower left.

Complex Sulfate Deposits in Coprates Chasma

NASA Technical Reports Server (NTRS)

2008-01-01

This image of layered sulfate-containing deposits in the Coprates Chasma region of Mars was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at 1827UTC (1:27 p.m. EST) on December 12, 2006 near 10.2 degrees south latitude, 68.8 degrees west longitude. The image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 40 meters (132 feet) across. The image is about 11 kilometers (6.8 miles) wide at its narrowest point.

Coprates Chasma forms part of the backbone of the Valles Marineris canyon system. It extends approximately east-west for roughly 966 kilometers (600 miles), and is one of the larger chasmata in the Valles Marineris system.

The top panel in the montage above shows the location of the CRISM image on a mosaic taken by the Mars Odyssey spacecraft's Thermal Emission Imaging System (THEMIS). The CRISM data covers an area centered on a knob near the chasma's northern wall.

The center left image, an infrared false color image, shows the knob's layered morphology. The center right image unveils the mineralogical signatures of some of those layers, with yellow representing monohydrated sulfates (sulfates with one water molecule incorporated into each molecule of the mineral) and purple representing polyhydrated sulfates (sulfates with multiple waters per mineral molecule).

The lower two images are renderings of data draped over topography with 3 times vertical exaggeration. These images provide a view of the topography and reveal how the sulfate deposits relate to that topography. Darker polyhydrated sulfates (purple) lie along the knob's western flank. Brighter, monohydrated sulfates (yellow) appear to be superimposed on polyhydrated sulfate deposits in the southwest corner of the image. These coarsely banded deposits continue along the southeast side of the knob.

There are two possible explanations for the compositional banding of these sulfates. The first is deposition of

Colorful Bedrock Exposed in a Landslide Scarp

NASA Image and Video Library

2016-12-07

The steep walls of Valles Marineris sometimes fail, creating giant landslides. This provides a clean exposure of the underlying bedrock. This image of the north wall of Ganges Chasma reveals bedrock with diverse colors and textures, representing different geologic units. http://photojournal.jpl.nasa.gov/catalog/PIA21217

Monoamine oxidase A genotype is associated with gang membership and weapon use.

PubMed

Beaver, Kevin M; DeLisi, Matt; Vaughn, Michael G; Barnes, J C

2010-01-01

A functional polymorphism in the promoter region of the monoamine oxidase A (MAOA) gene has been found to be associated with a broad range of antisocial phenotypes, including physical violence. At the same time, it is well known that gang members represent some of the most serious violent offenders. Even so, no research has ever examined the association between MAOA and gang membership. The aim of this study is to examine the association between MAOA and gang membership and between MAOA and weapon use. We examined the effects of MAOA by using a molecular genetic association research design. A nonclinical sample was used in this study. Participants were drawn from the National Longitudinal Study of Adolescent Health (1155 females, 1041 males). The outcome measures of this study are gang membership and weapon use. The low MAOA activity alleles conferred an increased risk of joining a gang and using a weapon in a fight for males but not for females. Moreover, among male gang members, those who used weapons in a fight were more likely to have a low MAOA activity allele when compared with male gang members who do not use weapons in a fight. Male carriers of low MAOA activity alleles are at risk for becoming a gang member and, once a gang member, are at risk for using weapons in a fight. Copyright 2010 Elsevier Inc. All rights reserved.

Western Candor Chasma, Valles Marineris

NASA Technical Reports Server (NTRS)

1998-01-01

One of the most striking discoveries of the Mars Global Surveyor mission has been the identification of thousands of meters/feet of layers within the wall rock of the enormous martian canyon system, Valles Marineris.

Valles Marineris was first observed in 1972 by the Mariner 9 spacecraft, from which the troughs get their name: Valles--valleys, Marineris--Mariner.

Some hints of layering in both the canyon walls and within some deposits on the canyon floors were seen in Mariner 9 and Viking orbiter images from the 1970s. The Mars Orbiter Camera on board Mars Global Surveyor has been examining these layers at much higher resolution than was available previously.

MOC images led to the realization that there are layers in the walls that go down to great depths. An example of the wall rock layers can be seen in MOC image 8403, shown above (C).

MOC images also reveal amazing layered outcrops on the floors of some of the Valles Marineris canyons. Particularly noteworthy is MOC image 23304 (D, above), which shows extensive, horizontally-bedded layers exposed in buttes and mesas on the floor of western Candor Chasma. These layered rocks might be the same material as is exposed in the chasm walls (as in 8403--C, above), or they might be rocks that formed by deposition (from water, wind, and/or volcanism) long after Candor Chasma opened up.

In addition to layered materials in the walls and on the floors of the Valles Marineris system, MOC images are helping to refine our classification of geologic features that occur within the canyons. For example, MOC image 25205 (E, above), shows the southern tip of a massive, tongue-shaped massif (a mountainous ridge) that was previously identified as a layered deposit. However, this MOC image does not show layering. The material has been sculpted by wind and mass-wasting--downslope movement of debris--but no obvious layers were exposed by these processes.

Valles Marineris a fascinating region on Mars that holds much

Combating Gangs: Federal Agencies Have Implemented a Central American Gang Strategy, but Could Strengthen Oversight and Measurement of Efforts. Report to Congressional Requesters. GAO-10-395

ERIC Educational Resources Information Center

Larence, Eileen R.

2010-01-01

Thousands of gang members in the United States belong to gangs such as MS-13 and 18th Street that are also active in Central American countries. Federal entities with responsibilities for addressing Central American gangs include the National Security Council (NSC); the Departments of Homeland Security (DHS), Justice (DOJ), and State; and the U.S.…

Moving beyond Labels: Approaching Gang Involvement through Behavior.

ERIC Educational Resources Information Center

Crowley, Carolyn L.; Lavery, Barbara; Siegel, Alexander W.; Cousins, Jennifer H.

This study examined the specific nature of the relationship between involvement in various risk-taking behaviors and levels of gang involvement. Forty-nine high school students, 24 girls and 25 boys, ages 14 to 18, from a rural Texas community, completed a gang involvement questionnaire and the Risk Inventory and Perception Scale during individual…

Awareness of Deaf Sign Language and Gang Signs.

ERIC Educational Resources Information Center

Smith, Cynthia; Morgan, Robert L.

There have been increasing incidents of innocent people who use American Sign Language (ASL) or another form of sign language being victimized by gang violence due to misinterpretation of ASL hand formations. ASL is familiar to learners with a variety of disabilities, particularly those in the deaf community. The problem is that gang members have…

Gang Youth, Substance Use Patterns, and Drug Normalization

ERIC Educational Resources Information Center

Sanders, Bill

2012-01-01

Gang membership is an indicator of chronic illicit substance use and such patterns of use may have a normalized character. Using epidemiological and qualitative data collected between 2006 and 2007, this manuscript examines the drug normalization thesis among a small sample (n=60) of gang youth aged 16-25 years from Los Angeles. Overall, while…

Sexual risk, substance use, mental health, and trauma experiences of gang-involved homeless youth.

PubMed

Petering, Robin

2016-04-01

This study examined the associations of sexual risk behaviors, substance use, mental health, and trauma with varying levels of gang involvement in a sample of Los Angeles-based homeless youths. Data were collected from 505 homeless youths who self-reported various health information and whether they have ever identified as or been closely affiliated with a gang member. Multivariable logistic regression assessed associations of lifetime gang involvement with risk taking behaviors and negative health outcomes. Results revealed seventeen percent of youths have ever identified as a gang member and 46% as gang affiliated. Both gang members and affiliates were at greater risk of many negative behaviors than non-gang involved youths. Gang members and affiliates were more likely to report recent methamphetamine use, cocaine use, chronic marijuana use, having sex while intoxicated, and symptoms of depression, symptoms of posttraumatic stress disorder. They were also more likely to have experienced childhood sexual abuse and witnessing family violence. Gang members were more likely to ever attempt suicide, experience recent partner violence, and report physical abuse during childhood. Results suggest that lifetime gang involvement is related to a trajectory of negative outcomes and amplified risk for youths experiencing homelessness. Additionally, being closely connected to a gang member appears to have just as much as an impact on risk as personally identifying as a gang member. Given the lack of knowledge regarding the intersection between youth homelessness and gang involvement, future research is needed to inform policies and programs that can address the specific needs of this population. Copyright © 2016 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

In Gangs We Trust: A Close-Up of the New Induction.

ERIC Educational Resources Information Center

Blankstein, Alan Meredith; Sandoval, Gilbert "Sandy"

1998-01-01

Explains how the needs children are trying to meet through gang involvement are the same ones that societies meet with rites of passage. Although gang rituals are antisocial, the needs they meet for youth are healthy. Offers several strategies that can be used when working with youth involved in gangs. Urges educators to help youth develop…

Childhood adversity and the continued exposure to trauma and violence among adolescent gang members

PubMed Central

Quinn, Katherine; Pacella, Maria L.; Dickson-Gomez, Julia; Nydegger, Liesl A.

2017-01-01

This study examines experiences of childhood adversity, trauma, and violence among adolescent gang members prior to and during adolescent gang involvement to better understand the effects of violence and trauma on gang members. We conducted 58 qualitative semi-structured interviews with members of six adolescent gangs. Data was analyzed using thematic content analysis and the constant comparative method in MAXQDA. Findings revealed that frequent and ongoing exposure to neighborhood violence and personal and familial trauma led many youth to normalize experiences of violence. Furthermore, although they believed gangs would offer protection and social support, gang membership led to additional exposure to violence and trauma and bleak future expectations. Interventions for adolescent gang members should address the complex childhoods and cumulative traumatic experiences of these adolescents. PMID:28262961

Gangs, clubs, and alcohol: The effect of organizational membership on adolescent drinking behavior.

PubMed

Suh, Chan S; Brashears, Matthew E; Genkin, Michael

2016-07-01

How does adolescent organizational membership in general, and simultaneous membership in distinct types of organizations in particular, impact drinking behavior? While past studies have focused either on the learning effect of involvement with gangs or on the constraining influence of conventional organizations on adolescent problem behavior, we explore the possibility that conventional school clubs can serve as socializing opportunities for existing gang members to engage in drinking behavior with non-gang club members. Using the Add Health data, we show that gang members drink more often, and engage in more binge drinking, than non-members. More importantly, individuals who are members of both gangs and school clubs drink alcohol at greater levels than those who are solely involved in gangs. In addition, non-gang adolescents who are co-members with gang members in the same school club are more likely to drink alcohol than non-members. This result has important implications for understanding the role of organizations in adolescent behavior and suggests that the study of delinquent behaviors would benefit from devoting more attention to individuals who bridge distinct types of organizations. Copyright © 2016 Elsevier Inc. All rights reserved.

Delinquency Among Members of Hong Kong Youth Street Gangs: The Role of the Organizational Structures of Gangs and Triad Affiliations.

PubMed

Chui, Wing Hong; Khiatani, Paul Vinod

2018-07-01

This study explores the importance of organizational structures and formal affiliations with the Hong Kong triads to delinquency among youth street gang members in Hong Kong. More specifically, this study examines the relative importance of the number of organizational structures and triad affiliation to patterns of delinquency in a sample of active members of youth street gangs ( N = 201). With the aid of outreach social workers, a convenience sampling method was used to recruit a gender-balanced sample of at-risk youths. Logistic regression analysis of the survey data that was gathered indicated that formal affiliation to Hong Kong triads and the presence of organizational structures significantly increased the odds of delinquency (independently of each other). Suggestions for future research on gang membership and delinquency, with particular reference to the Asian context, are provided.

Large impacts and tectonism: the relative ages of the basin Odysseus and Ithaca Chasma on Saturn's icy moon Tethys

NASA Astrophysics Data System (ADS)

Wagner, Roland; Stephan, Katrin; Schmedemann, Nico; Roatsch, Thomas; Kersten, Elke; Neukum, Gerhard; Denk, Tilmann; Porco, Carolyn C.

2014-05-01

Large impact events forming craters of basin size (> 200 - 300 km in diameter) on planets, asteroids or planetary satellites can cause intense tectonic deformation on their surfaces, indicated by concentric and/or radial troughs or ridges [e.g., 1]. Recently, sets of parallel grooves on asteroid (4) Vesta have been discussed to be the result of impact-related deformation in connection with basin-forming events on Vesta's south polar area [2]. On Saturn's mid-sized icy satellites Tethys, 1072 km in diameter, major landforms are the 445 km large impact basin Odysseus and the huge graben system of Ithaca Chasma which were first imaged during the Voyager encounters in 1980 and 1981 [3][4]. Ithaca Chasma is a ~100 km wide terraced trough. It has been discussed that Ithaca Chasma could be the result of structural deformation caused by the impact event that created Odysseus [4][5]. Preliminary mapping and crater counts using Cassini ISS imaging data on Odysseus and Ithaca Chasma, however, infer that this has not been the case [6]. Cassini VIMS spectral data show that Ithaca Chasma has less ice compared to Odysseus which supports this finding that it is older than the basin [7]. Major problems to exactly define the stratigraphic position of Ithaca Chasma with respect to the basin Odysseus are (1) that only those craters are allowed to be used for crater counts which clearly superimpose the tectonic structures (e.g., the terraced scarps) across the chasm, and (2) further geologic processes that affected the chasm interior caused obliteration of craters which results in lower crater frequencies. Our preliminary crater counts [6] were carried out on lower-resolution Cassini imaging data. During Cassini's orbital tour since July 2004, the ISS cameras have provided almost complete global image coverage of Tethys at resolutions of 100 - 300 m/pxl. In this work we present results from our ongoing studies on Tethys' geology, based on these new imaging data, primarily focused on

Can the Jamaican Security Forces Successfully Reduce the Violent Impact of Gangs?

DTIC Science & Technology

2012-12-14

movements in the form of local gangs, youth gangs and juvenile delinquents . In between these two extremes are other gangs of varied forms, composition and......others that are based on youth delinquency . Certainly, an operational unit by itself would not have the time during an ongoing operation to begin the

Gang Membership and Drug Involvement: Untangling the Complex Relationship

ERIC Educational Resources Information Center

Bjerregaard, Beth

2010-01-01

Previous research has consistently demonstrated a relationship between gang membership and involvement in illegal substances. In addition, researchers have noted that gang members are frequently more heavily involved in drug sales, which often lead to increases in violent behaviors. Most of this research, however, is either cross-sectional or…

Spectral Mapping of Interior Layered Deposits of Western Candor Chasma by CRISM

NASA Astrophysics Data System (ADS)

Murchie, S.; Roach, L.; Milliken, R.; Seelos, F.; Wiseman, S.; Humm, D.; Mustard, J.; Bibring, J.; CRISM Team

2007-12-01

Western Candor Chasma contains a 3 km-thick sequence of interior layered deposits (ILDs) that may have been emplaced by sedimentary deposition subsequent to formation of Valles Marineris. Proposed genetic mechanisms include subaerial fluvial deposition or volcanism, accumulation of airfall dust, lacustrine evaporite precipitation, hydrovolcanism, or alternatively deep erosion of the chasma wall materials. Observations by the Mars Express/OMEGA spectrometer showed that the ILDs contain both monohydrated and polyhydrated sulfates in close spatial association with fine-grained ferric oxides having distinctive visible-infrared absorptions (Gendrin et al. 2005a,b). In general, OMEGA data also suggest that monohydrated sulfates are associated with steeper slopes and higher albedos than are polyhydrated sulfates (Mangold 2006). CRISM has observed the ILDs in western Candor using both its 200 m/pixel global mapping mode and targeted observations at 20 or 40 m/pixel. CRISM data show spatial heterogeneity in spectral properties to the spatial resolution limit of the instrument. Both monohydrated sulfates (indicated by 2130- and 2400-nm absorptions) and polyhydrated sulfates (indicated by 1450-, 1940-, and 2420-nm absorptions) are evident at all elevations in the ILDs. Polyhydrate signatures occur on intermediate-albedo, relatively intact exposures of stratified material and are rare, but not absent, in nearby erosional debris. Typically the polyhydrate outcrops are low-sloped and form erosion-resistant cap rocks. The monohydrated sulfate also occurs in intermediate- to high-albedo outcrops, but is more commonly distributed as dark, erosional debris on ledges and in depressions that has been modified by wind to form dunes. Only in rare cases can the dark debris be associated with a discrete, dark source layer. The erosional debris exhibits enhancements in sulfate absorptions as well as in 530-, 660-, and 860- to 900-nm absorptions due to ferric iron minerals; different debris

Melas Chasma Landslide

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Context image for PIA03041 Dunes in Darwin Crater

The landslide in the center of this image occurred in the Melas Chasma region of Valles Marineris.

Image information: VIS instrument. Latitude 11S, Longitude 292.6E. 17 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Comparison of glue-line quality between gang edging and straight-line ripping

Treesearch

Charles J. Gatchell; James R. Olson; James R. Olson

1986-01-01

Gang edging with a dip-chain fed gang ripsaw produces gluing surfaces equal to those from a straight-line ripsaw in yellow-poplar (Liriodendron tulipifera) and red oak (Quercus rubra). Special care in gluing red oak was needed to get shear strengths equal to solid wood values. However, the strength comparisons between sawing methods showed no differences between gang...

Chasma Boreale in the North Polar Region

NASA Technical Reports Server (NTRS)

2006-01-01

This images shows a Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) full-resolution 'targeted image' of the edge of Mars' north polar cap. The region in the image, Chasma Boreale, is a valley several kilometers or miles deep that cuts about 400 kilometers (about 250 miles) into the edge of the cap.

This image was acquired at 0851 UTC (4:51 a.m. EDT) on Oct. 1, 2006, near 84.6 degrees north latitude, 3.6 degrees east longitude. It covers an area about 13 kilometers (8 miles) long and, at the narrowest point, about 9 kilometers (5.6 miles) wide. At the center of the image the spatial resolution is as good as 18 meters (60 feet) per pixel. The image was taken in 544 colors covering wavelengths of 0.36 to 3.92 micrometers. Two renderings of the data are shown here, both draped over topography without vertical exaggeration, and then viewed from a perspective diagonally above the site. The top view is an approximately true-color representation. The bottom view, constructed from infrared wavelengths, shows strength of the spectral signature of ice. Brighter areas are rich in ice, and dark areas have little ice.

The polar cap has long been recognized to contain layers composed of dust and ice, and hence has been named the polar layered deposit. This sits atop an underlying 'basal unit.' The upper part of the basal unit is dark at visible wavelengths and steeply sloped, whereas the lower part of the basal unit is brighter, redder, and layered like the polar layered deposits. The chasma floor is cratered, and in the foreground it is covered by dunes that are outliers of a north polar sand sea that surrounds the polar cap. The polar layered deposits and the basal unit form a steeply sloping scarp about 1.1 kilometers (0.7 miles) high.

CRISM's image of this region shows a number of previously unrecognized characteristics of the polar layered deposits and the basal unit. First, the ice-rich polar layered deposits exhibit coherent banding both at

Hematite-Rich Deposits in Capri Chasma

NASA Image and Video Library

2016-12-14

Capri Chasma is located in the eastern portion of the Valles Marineris canyon system, the largest known canyon system in the Solar System. Deeply incised canyons such as this are excellent targets for studying the Martian crust, as the walls may reveal many distinct types of bedrock. This section of the canyon was targeted by HiRISE based on a previous spectral detection of hematite-rich deposits in the area. Hematite, a common iron-oxide mineral, was first identified here by the Mars Global Surveyor Thermal Emission Spectrometer (TES). In this TES image, red pixels indicate higher abundances of hematite, while the blue and green pixels represent different types of volcanic rocks (e.g., basalt). Hematite in the Meridiani Planum region was also detected with the TES instrument (which we can see with the bright red spot on the Global TES mineral map). As a consequence, Meridiani Planum was the first landing site selected on Mars due to the spectral detection of a mineral that may have formed in the presence of liquid water. Shortly after landing, the Opportunity rover detected the presence of hematite in the form of concretions called "blueberries." The blueberries are found in association with layers of sulfate salt-rich rocks. The salts are hypothesized to have formed through the raising and lowering of the groundwater table. During one such an event, the rock altered to form the hematite-rich blueberries. As the rock was eroded away, the more resistant hematite-rich blueberries were plucked out and concentrated on the plains as a "lag" deposit. Martian blueberries are observed to be scattered across the plains of Meridiani along Opportunity's traverse from Eagle Crater to Endeavor Crater, where Opportunity continues to explore after its mission began over 10 years ago. This infrared-color image close-up highlights what is possibly the hematite-rich deposits nestled between different types of bedrock terraces in Capri Chasma. The bluish terrace is likely volcanic

Geologic Mapping of the Juno Chasma Quadrangle, Venus: Establishing the Relation Between Rifting and Volcanism

NASA Technical Reports Server (NTRS)

Senske, D. A.

2008-01-01

To understand the spatial and temporal relations between tectonic and volcanic processes on Venus, the Juno Chasma region is mapped. Geologic units are used to establish regional stratigraphic relations and the timing between rifting and volcanism.

Prevalence of Clonorchis sinensis Metacercariae in Fish from Water Systems of Seomjin-gang (River).

PubMed

Sohn, Woon-Mok; Na, Byoung-Kuk; Cho, Shin-Hyeong; Park, Mi-Yeoun; Kim, Cheon-Hyeon; Hwang, Min-Ah; No, Kyeong-Woo; Yoon, Ki-Bok; Lim, Hyun-Cheol

2017-06-01

The prevalence of Clonorchis sinensis metacercariae ( Cs Mc) was examined in freshwater fish from the water systems of Seomjin-gang (River), the Republic of Korea. Total 1,604 fish from 7 local sites of Seomjin-gang were examined by artificial digestion methods. The metacercariae of C. sinensis were detected in 102 (39.8%) out of 256 fish (14 species) from the upper reaches of Seomjin-gang, i.e., Osucheon (22.3% in 6 fish species) in Imsil-gun, and Seomjin-gang (63.9% in 9 fish species) in Sunchang-gun, Jeollabuk-do. Their average density was 9.0 per infected fish. They were also found in 132 (48.0%) out of 275 fish (12 spp.) from the middle reaches of Seomjin-gang, i.e., Songdaecheon (58.9% in 4 fish species) in Namwon-si, Jeollabuk-do, and Seomjin-gang (45.2% in 10 fish species) in Gokseong-gun, Jeollanam-do. Their average density was 21.0 per infected fish. Cs Mc were detected in 77 (56.6%) out of 136 fish (11 species) from the lower reaches of Seomjin-gang, i.e., Seomjin-gang (73.3% in 11 fish species) in Gurye-gun, Jeollanam-do, and Namsancheon (8.6% in 1 fish species) in Hadong-gun, Gyeongsangnam-do. Their average density was 64.9 per infected fish. The metacercariae of Metorchis orientalis were also detected in 6 fish species from 4 sites of Seomjin-gang. Conclusively, it has been confirmed that Cs Mc are more or less prevalent in fish from some water systems of Seomjin-gang in Korea.

Prevalence of Clonorchis sinensis Metacercariae in Fish from Water Systems of Seomjin-gang (River)

PubMed Central

Sohn, Woon-Mok; Na, Byoung-Kuk; Cho, Shin-Hyeong; Park, Mi-Yeoun; Kim, Cheon-Hyeon; Hwang, Min-Ah; No, Kyeong-Woo; Yoon, Ki-Bok; Lim, Hyun-Cheol

2017-01-01

The prevalence of Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fish from the water systems of Seomjin-gang (River), the Republic of Korea. Total 1,604 fish from 7 local sites of Seomjin-gang were examined by artificial digestion methods. The metacercariae of C. sinensis were detected in 102 (39.8%) out of 256 fish (14 species) from the upper reaches of Seomjin-gang, i.e., Osucheon (22.3% in 6 fish species) in Imsil-gun, and Seomjin-gang (63.9% in 9 fish species) in Sunchang-gun, Jeollabuk-do. Their average density was 9.0 per infected fish. They were also found in 132 (48.0%) out of 275 fish (12 spp.) from the middle reaches of Seomjin-gang, i.e., Songdaecheon (58.9% in 4 fish species) in Namwon-si, Jeollabuk-do, and Seomjin-gang (45.2% in 10 fish species) in Gokseong-gun, Jeollanam-do. Their average density was 21.0 per infected fish. CsMc were detected in 77 (56.6%) out of 136 fish (11 species) from the lower reaches of Seomjin-gang, i.e., Seomjin-gang (73.3% in 11 fish species) in Gurye-gun, Jeollanam-do, and Namsancheon (8.6% in 1 fish species) in Hadong-gun, Gyeongsangnam-do. Their average density was 64.9 per infected fish. The metacercariae of Metorchis orientalis were also detected in 6 fish species from 4 sites of Seomjin-gang. Conclusively, it has been confirmed that CsMc are more or less prevalent in fish from some water systems of Seomjin-gang in Korea. PMID:28719955

Risk and Protective Factors Associated with Gang Involvement among Urban African American Adolescents.

ERIC Educational Resources Information Center

Li, Xiaoming; Stanton, Bonita; Pack, Robert; Harris, Carole; Cottrell, Lesley; Burns, James

2002-01-01

Analyzed data about urban African American youth to explore whether differences in exposure to violence, resilience, and distress symptoms between gang members and nonmembers resulted from risk behaviors in which youths participated or from gang membership itself. Results indicated that gang membership itself related to increased risk and…

Highlights of the 2012 National Youth Gang Survey. Juvenile Justice Fact Sheet

ERIC Educational Resources Information Center

Egley, Arlen, Jr.; Howell, James C.; Harris, Meena

2014-01-01

This fact sheet provides an overview of the nation's gang problem and summarizes findings from the 2012 survey. Of the 2,538 survey recipients, 2,199 (87 percent) responded to the survey. In 2012, there were an estimated 30,700 gangs (an increase from 29,900 in 2011) and 850,000 gang members (an increase from 782,500 in 2011) throughout 3,100…

Adolescents, gangs, and perceptions of safety, parental engagement, and peer pressure.

PubMed

Kelly, Sarah E; Anderson, Debra G

2012-10-01

Adolescents are exposed to various forms of gang violence, and such exposure has led them to feel unsafe in their neighborhood and have differing interactions with their parents and peers. This qualitative study explored adolescents', parents', and community center employees' perceptions of adolescents' interaction with their neighborhood, family, and peers. Three themes emerged from the data: Most adolescents reported that the community center provided a safe environment for them; parental engagement influenced adolescents' experiences with gangs; and adolescents were subjected to peer pressure in order to belong. Exposure to gang violence can leave an impression on adolescents and affect their mental health, but neighborhood safety and relationships with parents and peers can influence adolescents' exposure to gang violence. Recommendations regarding the use of health care professionals at community centers are proposed. Copyright 2012, SLACK Incorporated.

Identification and spatial distribution of light-toned deposits enriched in Al-phyllosilicates on the plateaus around Valles Marineris, Mars

NASA Astrophysics Data System (ADS)

Le Deit, L.; Flahaut, J.; Quantin, C.; Allemand, P.

2009-12-01

The plateaus around Valles Marineris consist in series of mafic rocks suggested to be flood basalts (McEwen et al., 1998), lavas interbedded with sediments (Malin and Edgett, 2000), layered intrusive rocks (Williams et al., 2003), or lava flows dated from the Noachian to the late Hesperian epochs (Scott and Carr, 1978). Recent studies show the occurrence of light layered deposits of hundred meters thick cropping out on plateaus near Ius Chasma, Melas Chasma, Candor Chasma, Juventae Chasma and Ganges Chasma deposited during the Hesperian epoch by fluvio-lacustrine processes (Weitz et al., 2009), or by air-fall processes (Le Deit et al., 2009). These layered deposits are enriched in hydrated minerals including opaline silica (Milliken et al., 2008), hydroxylated ferric sulfates (Bishop et al., 2009), and possibly Al-rich phyllosilicates (Le Deit et al., 2009). We identified another type of formation corresponding to light-toned massive deposits cropping out around Valles Marineris. It appears that these light-toned deposits are associated to bright, rough, and highly cratered terrains, located beneath a dark and thin capping unit. Previous studies report the occurrence of phyllosilicates on few locations around Valles Marineris based on OMEGA data analyses (Gondet et al., 2007; Carter et al., 2009). The analysis of CRISM data show that the light-toned deposits are associated with spectra displaying absorption bands at 1.4 μm, 1.9 μm, and a narrow band at 2.2 μm. These spectral characteristics are consistent with the presence of Al-rich phyllosilicates such as montmorillonite, or illite in the light-toned deposits. They constitute dozens of outcrops located on the plateaus south and east of Coprates Chasma and Capri Chasma, and west of Ganges Chasma. All outcrops investigated so far are present over Noachian terrains mapped as the unit Npl2 by Scott and Tanaka (1986), and Witbeck et al. (1991). These light-toned deposits could result from in situ aqueous alteration

Lithium isotope behaviour during weathering in the Ganges Alluvial Plain

NASA Astrophysics Data System (ADS)

Pogge von Strandmann, Philip A. E.; Frings, Patrick J.; Murphy, Melissa J.

2017-02-01

The Ganges river system is responsible for the transportation of a large flux of dissolved materials derived from Himalayan weathering to the oceans. Silicate weathering-driven cooling resulting from uplift of the Himalayas has been proposed to be a key player in Cenozoic climate variation. This study has analysed Li isotope (δ7Li) ratios from over 50 Ganges river waters and sediments, in order to trace silicate weathering processes. Sediments have δ7Li of ∼0‰, identical to bulk continental crust, however suspended sediment depth profiles do not display variations associated with grain size that have been observed in other large river systems. Dissolved δ7Li are low (∼11‰) in the Ganges headwaters, but reach a constant value of 21 ± 1.6‰ within a relatively short distance downstream, which is then maintained for almost 2000 km to the Ganges mouth. Given that Li isotopes are controlled by the ratio of primary mineral dissolution to secondary mineral formation, this suggests that the Ganges floodplain is at steady-state in terms of these processes for most of its length. Low δ7Li in the mountainous regions suggest silicate weathering is therefore at its most congruent where uplift and fresh silicate exposure rates are high. However, there is no correlation between δ7Li and the silicate weathering rate in these rivers, suggesting that Li isotopes cannot be used as a weathering-rate tracer, although they do inform on weathering congruency and intensity. The close-to-constant δ7Li values for the final 2000 km of Ganges flow also suggest that once the size of the alluvial plain reached more than ∼500 km (the flow distance after which riverine δ7Li stops varying), the Ganges exerted little influence on the changing Cenozoic seawater δ7Li, because riverine δ7Li attained a near steady-state composition.

Geographical influences of an emerging network of gang rivalries

NASA Astrophysics Data System (ADS)

Hegemann, Rachel A.; Smith, Laura M.; Barbaro, Alethea B. T.; Bertozzi, Andrea L.; Reid, Shannon E.; Tita, George E.

2011-10-01

We propose an agent-based model to simulate the creation of street gang rivalries. The movement dynamics of agents are coupled to an evolving network of gang rivalries, which is determined by previous interactions among agents in the system. Basic gang data, geographic information, and behavioral dynamics suggested by the criminology literature are integrated into the model. The major highways, rivers, and the locations of gangs’ centers of activity influence the agents’ motion. We use a policing division of the Los Angeles Police Department as a case study to test our model. We apply common metrics from graph theory to analyze our model, comparing networks produced by our simulations and an instance of a Geographical Threshold Graph to the existing network from the criminology literature.

Reconsidering Hispanic Gang Membership and Acculturation in a Multivariate Context

ERIC Educational Resources Information Center

Miller, Holly Ventura; Barnes, J. C.; Hartley, Richard D.

2011-01-01

Previous qualitative research has suggested that Hispanic gang membership is linked to the process of acculturation. Specifically, studies have indicated that those who are less assimilated into mainstream American or "Anglo" society are at greater risk for joining gangs. Building on these observations, this study examines the relationship between…

Candor Chasma Mesa

NASA Technical Reports Server (NTRS)

2003-01-01

[figure removed for brevity, see original site]

A mantling layer of sediment slumps off the edge of a mesa in Candor Chasma producing a ragged pattern of erosion that hints at the presence of a volatile component mixed in with the sediment.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Image information: VIS instrument. Latitude -6.7, Longitude 286.4 East (73.6 West). 19 meter/pixel resolution.

Estimating the effect of gang membership on nonviolent and violent delinquency: a counterfactual analysis.

PubMed

Barnes, J C; Beaver, Kevin M; Miller, J Mitchell

2010-01-01

This study reconsiders the well-known link between gang membership and criminal involvement. Recently developed analytical techniques enabled the approximation of an experimental design to determine whether gang members, after being matched with similarly situated nongang members, exhibited greater involvement in nonviolent and violent delinquency. Findings indicated that while gang membership is a function of self-selection, selection effects alone do not account for the greater involvement in delinquency exhibited by gang members. After propensity score matching was employed, gang members maintained a greater involvement in both nonviolent and violent delinquency when measured cross-sectionally, but only violent delinquency when measured longitudinally. Additional analyses using inverse probability of treatment weights reaffirmed these conclusions. © 2010 Wiley-Liss, Inc.

Victory Junction Gang Camp

ERIC Educational Resources Information Center

Shell, Ryan

2007-01-01

This article describes the Victory Junction Gang Camp, a not-for-profit, NASCAR-themed camp for children with chronic medical conditions that serves 24 different disease groups. The mission of the camp is to give children life-changing camping experiences that are exciting, fun, and empowering in a safe and medically sound environment. While doing…

A Statewide Study of Gang Membership in California Secondary Schools

ERIC Educational Resources Information Center

Estrada, Joey Nuñez, Jr.; Gilreath, Tamika D.; Astor, Ron Avi; Benbenishty, Rami

2016-01-01

To date, there is a paucity of empirical evidence that examines gang membership in schools. Using statewide data of 7th-, 9th-, and 11th-grade students from California, this study focuses on the prevalence of gang membership by county, region, ethnicity, and grade level. Bivariate and multivariate logistic regression analyses were employed with…

Educators' Perspectives Regarding Youth Gang Activity and Prevention Efforts

ERIC Educational Resources Information Center

Fussy, Brooklyne

2017-01-01

Decreasing gang activity in inner city neighborhoods is an essential component to reducing violence and improving our society as a whole. This study was conducted to help generate awareness and a better understanding as to how schools can be best utilized as a protective factor against youth gang activity. The participants consisted of 6 educators…

Serious Delinquency and Gang Participation: Combining and Specializing in Drug Selling, Theft and Violence

PubMed Central

Gordon, Rachel A.; Rowe, Hillary L.; Pardini, Dustin; Loeber, Rolf; White, Helene Raskin; Farrington, David P.

2014-01-01

Using Pittsburgh Youth Study data, we examined the extent to which over 600 gang members and non-gang involved young men specialized in drug selling, serious theft, or serious violence or engaged simultaneously in these serious delinquent behaviors, throughout the 1990s. We found that the increase in delinquency associated with gang membership was concentrated in two combinations: serious violence and drug selling; serious violence, drug selling, and serious theft. Several covariates were similarly associated with multi-type serious delinquency and gang membership (age, historical time, Black race, and residential mobility), suggesting that these behaviors may share common developmental, familial, and contextual risks. We encourage future research to further examine the association of gang membership with engagement in particular configurations of serious delinquency. PMID:24954999

Serious Delinquency and Gang Participation: Combining and Specializing in Drug Selling, Theft and Violence.

PubMed

Gordon, Rachel A; Rowe, Hillary L; Pardini, Dustin; Loeber, Rolf; White, Helene Raskin; Farrington, David P

2014-06-01

Using Pittsburgh Youth Study data, we examined the extent to which over 600 gang members and non-gang involved young men specialized in drug selling, serious theft, or serious violence or engaged simultaneously in these serious delinquent behaviors, throughout the 1990s. We found that the increase in delinquency associated with gang membership was concentrated in two combinations: serious violence and drug selling; serious violence, drug selling, and serious theft. Several covariates were similarly associated with multi-type serious delinquency and gang membership (age, historical time, Black race, and residential mobility), suggesting that these behaviors may share common developmental, familial, and contextual risks. We encourage future research to further examine the association of gang membership with engagement in particular configurations of serious delinquency.

Associations between school violence, military connection, and gang membership in California secondary schools.

PubMed

Estrada, Joey Nuñez; Gilreath, Tamika D; Sanchez, Cathia Y; Astor, Ron Avi

2017-01-01

Recent studies have found that military-connected students confront many challenges-such as secondary traumatization-that may stem from a parent's deployment and frequent relocations. It is possible that multiple moves and deployments of family service members are associated with military-connected students' gang membership and involvement with school violence behaviors. In this study, a total of 13,484 students completed the core and military modules of the California Healthy Kids Survey. Logistic regressions examined the odds of a student being a member of a gang given their grade, gender, race/ethnicity, school violence behaviors, military-connectedness, changes in schools, and familial deployments. Results indicated that of the nearly 8% of students sampled who reported being in a gang, those with a parent or sibling currently serving in the military reported a higher prevalence rate of gang membership than students with no military connection. Students who reported being in fights or carrying weapons to school were at least twice more likely to be a gang member than students who reported not having been in fights or carrying weapons. Changing schools 4 or more times in a 5-year period and experiencing at least 1 familial deployment were also associated with an increased likelihood of gang membership. The findings of this study offer incentive to further explicate the gang and school violence experiences of military-connected students. This study supports schools in understanding the characteristics of the military-connected students and families they serve so they can implement appropriate interventions to curb gang and school violence behaviors. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Murder by structure: dominance relations and the social structure of gang homicide.

PubMed

Papachristos, Andrew V

2009-07-01

Most sociological theories consider murder an outcome of the differential distribution of individual, neighborhood, or social characteristics. And while such studies explain variation in aggregate homicide rates, they do not explain the social order of murder, that is, who kills whom, when, where, and for what reason. This article argues that gang murder is best understood not by searching for its individual determinants but by examining the social networks of action and reaction that create it. In short, the social structure of gang murder is defined by the manner in which social networks are constructed and by people's placement in them. The author uses a network approach and incident-level homicide records to recreate and analyze the structure of gang murders in Chicago. Findings demonstrate that individual murders between gangs create an institutionalized network of group conflict, net of any individual's participation or motive. Within this network, murders spread through an epidemic-like process of social contagion as gangs evaluate the highly visible actions of others in their local networks and negotiate dominance considerations that arise during violent incidents.

Sand-Venting in the M5.7 Earthquake 3 Jan 2017 and in the Much Larger Penultimate Liquefaction Event with their Sedimentary Setting in an Upstream Valley of the Ganges-Brahmaputra Delta: Implications for Earthquake Hazard

NASA Astrophysics Data System (ADS)

McHugh, C.; Seeber, L.; Akhter, S. H.; Schenck, R. J.; Steckler, M. S.; Kumar, B.; Rajapara, H.; Shovon, A. K.; Singhvi, A. K.

2017-12-01

The Ganges-Brahmaputra Delta (GBD) is near the cusp between Sunda subduction and Himalayan collision. Abundant water and fertile sediment support a huge population, but large earthquakes along these broad convergence boundaries have repeatedly caused widespread liquefaction and destruction. The 3 Jan 2017 M5.7 32 km deep (USGS) Ambassa (Tripura, India) earthquake accommodated down-dip extension of the Indian slab where it subducts eastward from the GBD below Burma. This is typical for current seismicity below and east of the GBD, although much larger and shallower thrust earthquakes are anticipated based on GPS. Generally, reported effects in the broad mesoseismal area seem consistent with hypocenter depth and the assigned max MMI V (USGS), but we found surprisingly intense damage and many liquefaction sites in the alluvial northern portion of the Dolai valley in Bangladesh, 36 km NNW of the epicenter. We trenched three liquefaction sites and completed a profile of ten 50m deep wells across the 5 km wide alluvial valley. Fluvial channel sands alternate with overbank silt/clay and organic clay layers suggesting frequent changes in river course, consistent with rapid post glacial sea-level rise, transgression, high-stand aggradation and differential tectonic uplift. The Dolai is one of several short low-relief synclinal valleys in the fold belt draining northward into the Sylhet Basin (NE part of the GBD) where they meet westward drainage richer in sediment. Rapid aggradation by this cross-drainage may have a damming effect and account for the current lacustrine/marshy conditions characteristic of the northern end of these synclinal valleys. Organic rich beds derived from such conditions could encourage overpressure and raise liquefaction potential. The 1.5 m deep trenches revealed fractures and clastic dykes <15 mm wide that fed the 2017 sand vents. Their orientations were N-S, subparallel to the valley and nearby river-banks and at high angle to the fold axes

LA's Gang-Busters--Lessons Learned.

ERIC Educational Resources Information Center

Harper, Suzanne

1989-01-01

Regarded as the nation's gang violence capital, Los Angeles' politicians and law enforcement and school administrators are using knowledge from lost battles to win the war. Solutions include targeting younger children, teaching self-esteem and communication skills, as well as organizing group graffiti cleanups. (SI)

“GETTING HIGH AND GETTING BY”: DIMENSIONS OF DRUG SELLING BEHAVIORS AMONG AMERICAN MEXICAN GANG MEMBERS IN SOUTH TEXAS

PubMed Central

Valdez, Avelardo; Sifaneck, Stephen J.

2010-01-01

This article discerns the role that Mexican American gang members play in drug markets, and the relationship between gang members’drug use and drug selling in South Texas. A four-part typology based on the two dimensions of gang type and gang member emerged from this qualitative analysis of 160 male gang members: Homeboys, Hustlers, Slangers, and Ballers. Major findings include the following: (1) many gang members are user/sellers and are not profit-oriented dealers, (2) gangs commonly do extend “protection” to drug-selling members, and (3) proximity to Mexican drug markets, adult prison gangs, and criminal family members may play important roles in whether these gang members have access and the profit potential to actually deal drugs. This research contributes to our complex intersections between gangs, drug using, and drug selling. PMID:21218191

Developmental Pathways of Youth Gang Membership: A Structural Test of the Social Development Model

PubMed Central

Hill, Karl G.; Gilman, Amanda B.; Howell, James C.; Catalano, Richard F.; Hawkins, J. David

2017-01-01

As a result of nearly 40 years of research using a risk and protective factor approach, much is known about the predictors of gang onset. Little theoretical work, however, has been done to situate this approach to studying gang membership within a more comprehensive developmental model. Using structural equation modeling techniques, the current study is the first to test the capacity of the social development model (SDM) to predict the developmental pathways that increase and decrease the likelihood of gang membership. Results suggest that the SDM provides a good accounting of the social developmental processes at age 13 that are predictive of later gang membership. These findings support the promotion of a theoretical understanding of gang membership that specifies both pro- and antisocial developmental pathways. Additionally, as the SDM is intended as a model that can guide preventive intervention, results also hold practical utility for designing strategies that can be implemented in early adolescence to address the likelihood of later gang involvement. Three key preventive intervention points to address gang membership are discussed, including promoting efforts to enhance social skills, increasing the availability of prosocial opportunities and rewarding engagement in these opportunities, and reducing antisocial socialization experiences throughout the middle- and high school years. PMID:29403146

Gangs: Straight Talk, Straight Up. A Practical Guide for Teachers, Parents, and the Community.

ERIC Educational Resources Information Center

Jensen, Mary M.; Yerington, Philip C.

This book is written about youth gangs with the aim of educating teachers and administrators, parents, and others who work with youth. The main emphasis is on gang identifiers and positive behavior management strategies and crisis intervention techniques that can be used in schools and the home. Section 1, "Youth Gangs Past and Present," provides…

The role of delinquency, proactive aggression, psychopathy and behavioral school engagement in reported youth gang membership.

PubMed

Ang, Rebecca P; Huan, Vivien S; Chan, Wei Teng; Cheong, Siew Ann; Leaw, Jia Ning

2015-06-01

Given the robust positive association between gangs and crime, a better understanding of factors related to reported youth gang membership is critical and especially since youth in gangs are a universal concern. The present study investigated the role of delinquency, proactive aggression, psychopathy and behavioral school engagement in reported youth gang membership using a large sample of 1027 Singapore adolescents. Results from logistic regression showed that delinquency, proactive aggression, and behavioral school engagement were statistically significant risk factors for reported youth gang membership, and that psychopathy was not related to reported gang membership. Implications for prevention and intervention work with respect to youth gang membership were discussed. In particular, strengthening students' engagement with school and meaningful school-related activities and developing supportive teacher-student relationships are particularly important in working with young people with respect to prevention work. Additionally, the present study's theoretical and empirical contributions were also discussed. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Youth Violence: Gangs on Main Street, USA. Issues in Brief.

ERIC Educational Resources Information Center

Hamner, Carole J.

This report profiles the issue of youth violence: the history of its appearance in U.S. culture, the recent escalation of gang activity in U.S. communities, and the strategies put forth in smaller cities to meet this challenge. The report notes that there has been an explosion of gang violence in the United States that has been fostered by a…

Gang Membership and Subsequent Engagement into a Drug Free Therapeutic Community

ERIC Educational Resources Information Center

Widlitz, Michelle; Dermatis, Helen; Galanter, Marc; Bunt, Gregory

2007-01-01

The purpose of the present study was to assess the relationship of history of gang involvement to engagement in Therapeutic Community (TC) treatment. Residents (N = 222) at two Daytop facilities completed a survey assessing sociodemographic characteristics, prior gang involvement and multiple aspects of TC functioning. Residents with prior gang…

Eos Chasma Landslides

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site]

This VIS image shows several landslides within Eos Chasma. Many very large landslides have occurred within different portions of Valles Marineris. Note where the northern wall has failed in a upside-down bowl shape, releasing the material that formed the landslide deposit.

Image information: VIS instrument. Latitude -8, Longitude 318.6 East (41.4 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Teenagers, Clothes, and Gang Violence.

ERIC Educational Resources Information Center

Burke, Jim

1991-01-01

A California English teacher explores the school safety issue for both innercity and suburban high schools students. Wearing certain sports team jackets can place kids in danger; girls degrade themselves by keeping gang members' drugs and guns in their lockers. Schools can help reclaim the "Great Disconnected" by developing…

Gang membership and substance use: guilt as a gendered causal pathway

PubMed Central

Coffman, Donna L.; Melde, Chris; Esbensen, Finn-Aage

2014-01-01

Objectives We examine whether anticipated guilt for substance use is a gendered mechanism underlying the noted enhancement effect of gang membership on illegal drug use. We also demonstrate a method for making stronger causal inferences when assessing mediation in the presence of moderation and time-varying confounding. Methods We estimate a series of inverse propensity weighted models to obtain unbiased estimates of mediation in the presence of confounding of the exposure (i.e., gang membership) and mediator (i.e., anticipated guilt) using three waves of data from a multi-site panel study of a law-related education program for youth (N=1,113). Results The onset of gang membership significantly decreased anticipated substance use guilt among both male and female respondents. This reduction was significantly associated with increased frequency of substance use only for female respondents, however, suggesting that gender moderates the mechanism through which gang membership influences substance use. Conclusions Criminologists are often concerned with identifying causal pathways for antisocial and/or delinquent behavior, but confounders of the exposure, mediator, and outcome often interfere with efforts to assess mediation. Many new approaches have been proposed for strengthening causal inference for mediation effects. After controlling for confounding using inverse propensity weighting, our results suggest that interventions aimed at reducing substance use by current and former female gang members should focus on the normative aspects of these behaviors. PMID:26190954

Gang membership and substance use: guilt as a gendered causal pathway.

PubMed

Coffman, Donna L; Melde, Chris; Esbensen, Finn-Aage

2015-03-01

We examine whether anticipated guilt for substance use is a gendered mechanism underlying the noted enhancement effect of gang membership on illegal drug use. We also demonstrate a method for making stronger causal inferences when assessing mediation in the presence of moderation and time-varying confounding. We estimate a series of inverse propensity weighted models to obtain unbiased estimates of mediation in the presence of confounding of the exposure (i.e., gang membership) and mediator (i.e., anticipated guilt) using three waves of data from a multi-site panel study of a law-related education program for youth ( N =1,113). The onset of gang membership significantly decreased anticipated substance use guilt among both male and female respondents. This reduction was significantly associated with increased frequency of substance use only for female respondents, however, suggesting that gender moderates the mechanism through which gang membership influences substance use. Criminologists are often concerned with identifying causal pathways for antisocial and/or delinquent behavior, but confounders of the exposure, mediator, and outcome often interfere with efforts to assess mediation. Many new approaches have been proposed for strengthening causal inference for mediation effects. After controlling for confounding using inverse propensity weighting, our results suggest that interventions aimed at reducing substance use by current and former female gang members should focus on the normative aspects of these behaviors.

Scarp within Chasma Boreale

NASA Technical Reports Server (NTRS)

2006-01-01

This HiRISE image is of the north polar layered deposits (PLD) and underlying units exposed along the margins of Chasma Boreale. Chasma Boreale is the largest trough in the north PLD, thought to have formed due to outflow of water from underneath the polar cap, or due to winds blowing off the polar cap, or a combination of both. At the top and left of the image, the bright area with uniform striping is the gently sloping surface of the PLD. In the middle of the image this surface drops off in a steeper scarp, or cliff. At the top of this cliff we see the bright PLD in a side view, or cross-section. From these two perspectives of the PLD it is evident that the PLD are a stack of roughly horizontal layers. The gently sloping top surface cuts through the vertical sequence of layers at a low angle, apparently stretching the layers out horizontally and thus revealing details of the brightness and texture of individual layers. The surface of the PLD on the scarp is also criss-crossed by fine scale fractures. The layers of the PLD are probably composed of differing proportions of ice and dust, believed to be related to the climate conditions at the time they were deposited. In this way, sequences of polar layers are records of past climates on Mars, as ice cores from terrestrial ice sheets hold evidence of past climates on Earth. Further down the scarp in the center of the image the bright layers give way suddenly to a much darker section where a few layers are visible intermittently amongst aprons of dark material. The darkest material, with a smooth surface suggestive of loose grains, is thought to be sandy because similar exposures elsewhere show it to be formed into dunes by the wind. An intermediate-toned material also appears to form aprons draped over layers in the scarp, but its surface contains lobate structures that appear hardened into place and its edges are more abrupt in places, suggesting it may contain some ice or other cementing agent that makes it

Understanding Gang Membership and Crime Victimization among Jail Inmates: Testing the Effects of Self-Control

ERIC Educational Resources Information Center

Fox, Kathleen A.; Lane, Jodi; Akers, Ronald L.

2013-01-01

Although previous research has examined factors related to gang membership and offending, research on the relationship between gangs and victimization is limited. The present study builds on previous research and examines gang membership, victimization, and self-control among 2,414 jail inmates. Results from self-report surveys indicate that gang…

Gang membership of California middle school students: behaviors and attitudes as mediators of school violence.

PubMed

Estrada, Joey Nuñez; Gilreath, Tamika D; Astor, Ron Avi; Benbenishty, Rami

2013-08-01

Empirical evidence examining how risk and protective behaviors may possibly mediate the association between gang membership and school violence is limited. This study utilizes a statewide representative sample of 152 023 Latino, Black and White seventh graders from California to examine a theoretical model of how school risk (e.g. truancy, school substance use and risky peer approval) and protective (e.g. connectedness, support and safety) behaviors and attitudes mediate the effects of gang membership on school violence behaviors. The dataset was collected in the 2005-2006 and 2006-2007 academic school years using the ongoing large-scale California Healthy Kids Survey conducted by WestEd for the State of California. Approximately 9.5% of the sample considered themselves to be a member of a gang. The findings indicate that school risk behaviors and attitudes mediate the association between gang membership and school violence behaviors. Although the direct negative association between gang membership and school violence perpetration is weak, the positive indirect effect mediated by school risks behaviors and attitudes is strong. This indicates that when gang members engage in school risk behaviors, they are much more likely to be school violence perpetrators. Implications for further research, theory and practice for both gang and school violence researchers are discussed.

Reviving the Ganges Water Machine: potential

NASA Astrophysics Data System (ADS)

Amarasinghe, Upali Ananda; Muthuwatta, Lal; Surinaidu, Lagudu; Anand, Sumit; Jain, Sharad Kumar

2016-03-01

The Ganges River basin faces severe water challenges related to a mismatch between supply and demand. Although the basin has abundant surface water and groundwater resources, the seasonal monsoon causes a mismatch between supply and demand as well as flooding. Water availability and flood potential is high during the 3-4 months (June-September) of the monsoon season. Yet, the highest demands occur during the 8-9 months (October-May) of the non-monsoon period. Addressing this mismatch, which is likely to increase with increasing demand, requires substantial additional storage for both flood reduction and improvements in water supply. Due to hydrogeological, environmental, and social constraints, expansion of surface storage in the Ganges River basin is problematic. A range of interventions that focus more on the use of subsurface storage (SSS), and on the acceleration of surface-subsurface water exchange, has long been known as the Ganges Water Machine (GWM). The approach of the GWM for providing such SSS is through additional pumping and depleting of the groundwater resources prior to the onset of the monsoon season and recharging the SSS through monsoon surface runoff. An important condition for creating such SSS is the degree of unmet water demand. The paper shows that the potential unmet water demand ranging from 59 to 124 Bm3 year-1 exists under two different irrigation water use scenarios: (i) to increase irrigation in the Rabi (November-March) and hot weather (April-May) seasons in India, and the Aman (July-November) and Boro (December-May) seasons in Bangladesh, to the entire irrigable area, and (ii) to provide irrigation to Rabi and the hot weather season in India and the Aman and Boro seasons in Bangladesh to the entire cropped area. However, the potential for realizing the unmet irrigation demand is high only in 7 sub-basins in the northern and eastern parts, is moderate to low in 11 sub-basins in the middle, and has little or no potential in 4 sub

Risk Behaviors Among Young Mexican American Gang-Associated Females: Sexual Relations, Partying, Substance Use, and Crime

PubMed Central

Cepeda, Alice; Valdez, Avelardo

2010-01-01

This research focuses on young Mexican American girls who are not formal gang members yet participate in street-based activities of male gangs and engage in risk behaviors. These females comprise a larger proportion associated with male gangs in inner-city neighborhoods than actual female gang members. Using a qualitative design, the article presents a typology of Mexican American females that reveals a hierarchy based on exposure to four risk-related activities: sexual relations, partying, substance use, and crime. Findings illustrate how outcomes associated with these activities vary according to the girl’s relationship to the male gang and status within the community. Also, regardless of their relationship to the gang, participation in these activities resulted in different degrees of negative outcomes. The study concludes that problems associated with these females must go beyond being viewed as individual problems but rather seen within the social, cultural, and economic conditions of their environment. PMID:21218177

Gang Involvement among Immigrant and Refugee Youth: A Developmental Ecological Systems Approach

ERIC Educational Resources Information Center

Goodrum, Nada M.; Chan, Wing Yi; Latzman, Robert D.

2015-01-01

Immigrant and refugee youth are at elevated risk for joining gangs, which, in turn, is associated with a host of maladaptive outcomes. Previous literature on risk and protective factors for immigrant and refugee youth gang involvement has been inconclusive. Applying a developmental ecological systems approach, this study investigated contextual…

Deposits along the Northern Wall of Melas Chasma

NASA Image and Video Library

2016-10-05

It has been known since the 1970s when the Viking orbiters took pictures of Mars that there are large (i.e., several kilometers-thick) mounds of light-toned deposits within the central portion of Valles Marineris. More recent higher resolution images of Mars, including this image of Melas Chasma, show that the wall rocks of Valles Mariners also contain similar, albeit thinner, light-toned deposits. Spectral data from the CRISM instrument indicate that the larger mounds are composed of sulfates. Some of the wall rock deposits are also made up of sulfates, but others contain clays or mixtures of several kinds of hydrated materials, suggesting that multiple aqueous processes, perhaps at different times within Valles Marineris, formed the variety of deposits we now observe. http://photojournal.jpl.nasa.gov/catalog/PIA21102

Any of them will do: In-group identification, out-group entitativity, and gang membership as predictors of group-based retribution.

PubMed

Vasquez, Eduardo A; Wenborne, Lisa; Peers, Madeline; Alleyne, Emma; Ellis, Kirsty

2015-05-01

In non-gang populations, the degree of identification with an in-group and perceptions of out-group entitativity, the perception of an out-group as bonded or unified, are important contributors to group-based aggression or vicarious retribution. The link between these factors and group-based aggression, however, has not been examined in the context of street gangs. The current study assessed the relationship among in-group identification, perceptions of out-group entitativity, and the willingness to retaliate against members of rival groups who did not themselves attack the in-group among juvenile gang and non-gang members in London. Our results showed the predicted membership (gang/non-gang) × in-group identification × entitativity interaction. Decomposition of the three-way interaction by membership revealed a significant identification × entitativity interaction for gang, but not for non-gang members. More specifically, gang members who identify more strongly with their gang and perceived a rival group as high on entitativity were more willing to retaliate against any of them. In addition, entitativity was a significant predictor of group-based aggression after controlling for gender, in-group identification, and gang membership. Our results are consistent with socio-psychological theories of group-based aggression and support the proposal that such theories are applicable for understanding gang-related violence. Aggr. Behav. 41:242-252, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Geometric comparison of deep-seated gravitational spereading features on Mars (Coprates Chasma, Valles Marineris) and Earth (Ornak, Tatra Mountains)

NASA Astrophysics Data System (ADS)

Kromuszczyńska, O.; Mège, D.

2014-04-01

Uphill-facing normal faults scarps and crestal grabens, which are characteristic of deep-seated gravitational spreading (DSGS) of topographic ridges, are described in Coprates Chasma in Valles Marineris, Mars, and Ornak ridge and compared. The vertical offset of normal faults in the Martian instances varies from 40 to 1000 meters, with an average of 300 meters. The terrestrial faults offset is between few teens of centimeters up to 34 meters with an average of 10 meters. The values of horizontal displacement in Coprates Chasma vary from 10 to 680 meters, and at Ornak are in a range between 1 and 20 meters. Such difference corresponds with the difference of ridges scale and is due to the topographic gradient which is one order of magnitude higher on Mars than on Earth.

Canadian Female Gang Inmates: Risk, Needs, and the Potential for Prison Rehabilitation

ERIC Educational Resources Information Center

Scott, Terri-Lynne; Ruddell, Rick

2011-01-01

A comparison of the characteristics of 337 Canadian adult female gang offenders with a matched sample of women offenders showed that they were more likely to have been sentenced for violent offenses, had a greater number of prior youth and criminal convictions, and served prior terms of incarceration. Gang members were also assessed as having…

The Impact of Location Alteration on School Attendance of Chicano Gang Members.

ERIC Educational Resources Information Center

Hunsaker, Alan C.

The study examined whether a change in school site affected the school attendance of 13 male Chicano gang members, 13 to 18 years of age, admitted to a community-based delinquency and gang violence prevention project. Since an active Alternative Studies Program, designed for students with special learning problems or for working students, already…

[Violent youth gangs in Madrid: socialization and culturalization].

PubMed

Martín, María Jesús; Martínez, José Manuel; Rosa, Alberto

2009-08-01

This study explores the subject of youth involved in violent groups or gangs, with the goal of further understanding the indoctrination, socialization, and culturalization processes undergone by youth involved in group violence or gangs. Furthermore, to examine the dynamics between peer pressure and other social factors (dating relationships, work, family, etc.) within the theoretical framework of the theories of primary socialization and differential socialization. A qualitative analysis of 40 interviews of youth belonging to violent gangs/groups. According to the theories of primary socialization and differential socialization, over socialization by the violent group and under socialization by all other social entities can be assumed. Regarding parental supervision and support, three family types were clearly associated with the problem of youth violence. The distinct or unified social identity of the violent youth, as well as their individual self esteem and self image, formed a combination of processes whose relevance was highly predictive. Lastly, an accurate indicator of how these youth mature is their support network-perceived, absolute, and relative (distributed among the various influencing forces). The study clearly outlines the need for re-imposing fundamental philosophical epistemology and methodologies on social forces of this kind, incorporating elements key to the postmodern, constructionist, and opposing perspectives.

Mars Orbiter Camera High Resolution Images: Some Results From The First 6 Weeks In Orbit

NASA Technical Reports Server (NTRS)

1997-01-01

The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images acquired shortly after orbit insertion were relatively poor in both resolution and image quality. This poor performance was solely the result of low sunlight conditions and the relative distance to the planet, both of which have been progressively improving over the past six weeks. Some of the better images are used here (see PIA01021 through PIA01029) to illustrate how the MOC images provide substantially better views of the martian surface than have ever been recorded previously from orbit.

This U.S. Geological Survey shaded relief map provides an overall context for the MGS MOC images of the Tithonium/Ius Chasma, Ganges Chasma, and Schiaparelli Crater. Closeup images of the Tithonium/Ius Chasma area are visible in PIA01021 through PIA01023. Closeups of Ganges Chasma are available as PIA01027 through PIA01029, and Schiaparelli Crater is shown in PIA01024 through PIA01026. The Mars Pathfinder landing site is shown to the north of the sites of the MGS images.

Launched on November 7, 1996, Mars Global Surveyor entered Mars orbit on Thursday, September 11, 1997. The original mission plan called for using friction with the planet's atmosphere to reduce the orbital energy, leading to a two-year mapping mission from close, circular orbit (beginning in March 1998). Owing to difficulties with one of the two solar panels, aerobraking was suspended in mid-October and resumed in November 8. Many of the original objectives of the mission, and in particular those of the camera, are likely to be accomplished as the mission progresses.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from

Who Needs Enemies with Friends like These? The Importance of Place for Young People Living in Known Gang Areas

ERIC Educational Resources Information Center

Ralphs, Robert; Medina, Juanjo; Aldridge, Judith

2009-01-01

Despite a growing concern about gangs in Britain, academic research that focuses on gangs remains scarce. Drawing on data from the ESRC-funded ethnographic research YOGEC (Youth Gangs in an English City) project, this paper explores the negotiation of space and place by young people living in inner-city areas affected by gangs. Using a combination…

A Phenomenological Study with Youth Gang Members: Results and Implications for School Counselors.

ERIC Educational Resources Information Center

Omizo, Michael M.; Omizo, Sharon A.; Honda, Marianne R.

1997-01-01

Using a phenomenological model, examines eight male adolescents' perceptions of their gang membership. Interviews revealed such themes as self-esteem, a sense of belonging, and protection. Outlines implications for school counselors when working with gang members individually, in groups, with families, or during school interventions. (RJM)

Geologic map of the Artemis Chasma quadrangle (V-48), Venus

USGS Publications Warehouse

Bannister, Roger A.; Hansen, Vicki L.

2010-01-01

Artemis, named for the Greek goddess of the hunt, represents an approximately 2,600 km diameter circular feature on Venus, and it may represent the largest circular structure in our solar system. Artemis, which lies between the rugged highlands of Aphrodite Terra to the north and relatively smooth lowlands to the south, includes an interior topographic high surrounded by the 2,100-km-diameter, 25- to 200-km-wide, 1- to 2-km-deep circular trough, called Artemis Chasma, and an outer rise that grades outward into the surrounding lowland. Although several other chasmata exist in the area and globally, other chasmata have generally linear trends that lack the distinctive circular pattern of Artemis Chasma. The enigmatic nature of Artemis has perplexed researchers since Artemis Chasma was first identified in Pioneer Venus data. Although Venus' surface abounds with circular to quasi-circular features at a variety of scales, including from smallest to largest diameter features: small shield edifices (>1 km), large volcanic edifices (100-1,000 km), impact craters (1-270 km), coronae (60-1,010 km), volcanic rises and crustal plateaus (~1,500-2,500 km), Artemis defies classification into any of these groups. Artemis dwarfs Venus' largest impact crater, Mead (~280 km diameter); Artemis also lacks the basin topography, multiple ring structures, and central peak expected for large impact basins. Topographically, Artemis resembles some Venusian coronae; however Artemis is an order of magnitude larger than the average corona (200 km) and about twice the size of Heng-O Corona (which is 1,010 km in diameter), the largest of Venusian coronae. In map view Artemis' size and shape resemble volcanic rises and crustal plateaus; however, both of these classes of features differ topographically from Artemis. Volcanic rises and crustal plateaus form broad domical regions, and steep-sided regions with flat tops, respectively; furthermore, neither rises nor plateaus include circular troughs

Young Mother (in the) Hood: Gang Girls’ Negotiation of New Identities

PubMed Central

Moloney, Molly; Joe-Laidler, Karen; McKenzie, Kathleen

2010-01-01

This article examines the experiences of young women in street gangs who become mothers. Drawing on qualitative interviews with 65 young women in the San Francisco, CA, Bay Area, we examine their narratives about the transition to motherhood. In particular, we focus on the ways these young women negotiate femininities and attempt to reconcile their identities as young mothers and gang girls—both stigmatized identities. For many of the young women, motherhood entails a retreat from the street and a renewed emphasis on time spent in the home. While many receive (financial and childcare) support from their families, this also often means a diminution of the autonomy they experienced while more heavily involved in the gang. Issues of respect and respectability remain important for the young women, but the dimensions on which these are based change. PMID:21116461

Individual and Familial Characteristics of Youths Involved in Street Corner Gangs in Singapore.

ERIC Educational Resources Information Center

Kee, C.; Sim, K.; Teoh, J.; Tian, C. S.; Ng, K. H.

2003-01-01

Study compares 36 youths involved in street corner gangs in Singapore with 91 age-matched controls on measures of self-esteem, aggression, dysfunctional parenting and parent-adolescent communication. Results revealed that gang youths had lower self-esteem and higher levels of aggression than controls. Findings diverge from anticipated familial…

Spectral and stratigraphic mapping of hydrated minerals associated with interior layered deposits near the southern wall of Melas Chasma, Mars

NASA Astrophysics Data System (ADS)

Liu, Yang; Goudge, Timothy A.; Catalano, Jeffrey G.; Wang, Alian

2018-03-01

Orbital remote sensing data acquired from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard Mars Reconnaissance Orbiter (MRO), in conjunction with other datasets, are used to perform detailed spectral and stratigraphic analyses over a portion of south Melas Chasma, Mars. The Discrete Ordinate Radiative Transfer (DISORT) model is used to retrieve atmospherically corrected single scattering albedos from CRISM I/F data for mineral identification. A sequence of interbedded poly- and monohydrated sulfates associated with interior layered deposits (ILDs) is identified and mapped. Analyses from laboratory experiments and spectral unmixing of CRISM hyperspectral data support the hypothesis of precipitation and dehydration of multiple inputs of complex Mg-Ca-Fe-SO4-Cl brines. In this scenario, the early precipitated Mg sulfates could dehydrate into monohydrated sulfate due to catalytic effects, and the later-precipitated Mg sulfates from the late-stage "clean" brine could terminate their dehydration at mid-degree of hydration to form a polyhydrated sulfate layer due to depletion of the catalytic species (e.g., Ca, Fe, and Cl). Distinct jarosite-bearing units are identified stratigraphically above the hydrated sulfate deposits. These are hypothesized to have formed either by oxidation of a fluid containing Fe(II) and SO4, or by leaching of soluble phases from precursor intermixed jarosite-Mg sulfate units that may have formed during the later stages of deposition of the hydrated sulfate sequence. Results from stratigraphic analysis of the ILDs show that the layers have a consistent northward dip towards the interior of the Melas Chasma basin, a mean dip angle of ∼6°, and neighboring strata that are approximately parallel. These strata are interpreted as initially sub-horizontal layers of a subaqueous, sedimentary evaporite deposits that underwent post-depositional tilting from slumping into the Melas Chasma basin. The interbedded hydrated sulfate

Reasons and Remedies for Gangs and Delinquency among School Age Children. Literature Review.

ERIC Educational Resources Information Center

Sloan, David L.

Some of the common characteristics associated with juveniles who become involved in gang activities are identified. Programs that attempt to alleviate the situations that lead to gang involvement and programs that deal with juvenile delinquents are discussed. The history of the juvenile justice system is also traced. Characteristics that can…

Cognitive and Social Influences on Gang Involvement among Delinquents in Three Chinese Cities

ERIC Educational Resources Information Center

Ngai, Ngan-pun; Cheung, Chau-kiu; Ngai, Steven Sek-Yum

2007-01-01

Inasmuch as research has held the increase in youth gang activities responsible for the escalating level of crime and delinquency in Chinese societies, ascertaining risk or protective factors of gang involvement among Chinese youths is crucial. The factors include those associated with social control, social learning, and cognitive development. To…

“Get Off Me”: Perceptions of Disrespectful Police Behavior among Ethnic Minority Youth Gang Members

PubMed Central

Novich, Madeleine; Hunt, Geoffrey

2018-01-01

Recent media accounts have highlighted issues of use and abuse of police force and policing practices targeted at ethnic minorities within inner city areas. To date, little research has focused specifically on the experiences and perceptions of youth gang members in dealing with police. Using data from 253 in-depth interviews with ethnic minority San Francisco-based youth gang members, we examine perceptions of respectful and disrespectful police behavior. Premised on a procedural justice model (Tyler, 2006), we explore how frequently disrespectful police behavior is reported and how these negative experiences shape gang members’ attitudes towards the police more generally. We refine our investigation by comparing adverse encounters to examples in which gang members are treated respectfully. Using a data-driven inductive and qualitative theory testing deductive approach, our data revealed that male and female gang members regularly experience disrespectful police behavior in terms of physical and verbal abuse. Our findings indicate that these exchanges contribute to negative attitudes, fear, and distrust of police, while respectful interactions are meaningful and can contribute to positive attitudes towards officers. PMID:29910539

Western Candor Chasma - Layers exposed near the middle

NASA Technical Reports Server (NTRS)

1998-01-01

One of the most striking discoveries of the Mars Global Surveyor mission has been the identification of thousands of meters/feet of layers within the wall rock of the enormous martian canyon system, Valles Marineris.

Valles Marineris was first observed in 1972 by the Mariner 9 spacecraft, from which the troughs get their name: Valles--valleys, Marineris--Mariner.

Some hints of layering in both the canyon walls and within some deposits on the canyon floors were seen in Mariner 9 and Viking orbiter images from the 1970s. The Mars Orbiter Camera on board Mars Global Surveyor has been examining these layers at much higher resolution than was available previously.

MOC images led to the realization that there are layers in the walls that go down to great depths. An example of the wall rock layers can be seen in MOC image 8403, shown above (C).

MOC images also reveal amazing layered outcrops on the floors of some of the Valles Marineris canyons. Particularly noteworthy is MOC image 23304 (D, above), which shows extensive, horizontally-bedded layers exposed in buttes and mesas on the floor of western Candor Chasma. These layered rocks might be the same material as is exposed in the chasm walls (as in 8403--C, above), or they might be rocks that formed by deposition (from water, wind, and/or volcanism) long after Candor Chasma opened up.

In addition to layered materials in the walls and on the floors of the Valles Marineris system, MOC images are helping to refine our classification of geologic features that occur within the canyons. For example, MOC image 25205 (E, above), shows the southern tip of a massive, tongue-shaped massif (a mountainous ridge) that was previously identified as a layered deposit. However, this MOC image does not show layering. The material has been sculpted by wind and mass-wasting--downslope movement of debris--but no obvious layers were exposed by these processes.

Valles Marineris a fascinating region on Mars that holds much

Gangkill: An Exploratory Empirical Assessment of Gang Membership, Homicide Offending, and Prison Misconduct

ERIC Educational Resources Information Center

Drury, Alan J.; DeLisi, Matt

2011-01-01

Extant research indicates that inmates with street gang history are prone for prison misconduct but that inmates convicted of homicide offenses are less likely to be noncompliant. No research has explored the interaction between street gang history and homicide offending. Based on official infraction data from 1,005 inmates selected from the…

Acculturative Stress and Gang Involvement among Latinos: U.S.-Born versus Immigrant Youth

ERIC Educational Resources Information Center

Barrett, Alice N.; Kuperminc, Gabriel P.; Lewis, Kelly M.

2013-01-01

Gang involvement is an increasing issue among Latino youth, yet nuanced research on its potential causes is scarce. Quantitative and qualitative data were used to explore links between acculturative stress and gang involvement among immigrant and U.S.-born Latino middle school students (N = 199). Regression analyses showed that U.S.-born youths…

The Gang's All Here: Grammar Goes Global for Purdue, Unisa and Adelaide University

ERIC Educational Resources Information Center

Duff, Andrea; Spangenberg, Brady; Carter, Susanna; Miller, Julia

2010-01-01

The University of South Australia and Purdue University (Indiana) launched the "Grammar Gang Blog" in June 2008, as a collaborative forum for talking about language. The blog reaches a far-flung community of learners from Australia to the United States, Brisbane to Bangalore and Ghana to Germany. The Grammar Gang--where Owls meet…

Understanding the Black Box of Gang Organization: Implications for Involvement in Violent Crime, Drug Sales, and Violent Victimization

ERIC Educational Resources Information Center

Decker, Scott H.; Katz, Charles M.; Webb, Vincent J.

2008-01-01

This article examines the influence of gang organization on several behavioral measures. Using interview data from juvenile detention facilities in three Arizona sites, this article examines the relationship between gang organizational structure and involvement in violent crime, drug sales, victimization, and arrest. The gang literature suggests…

Alcohol and Drug Use among Gang Members: Experiences of Adolescents Who Attend School

ERIC Educational Resources Information Center

Swahn, Monica H.; Bossarte, Robert M.; West, Bethany; Topalli, Volkan

2010-01-01

Background: Problems related to gangs have been noted in large cities and in many schools across the United States. This study examined the patterns of alcohol, drug use, and related exposures among male and female high school students who were gang members. Methods: Analyses were based on the Youth Violence Survey, conducted in 2004, and…

Hydraulic Actuator for Ganged Control Rods

NASA Technical Reports Server (NTRS)

Thompson, D. C.; Robey, R. M.

1986-01-01

Hydraulic actuator moves several nuclear-reactor control rods in unison. Electromagnetic pump pushes liquid lithium against ends of control rods, forcing them out of or into nuclear reactor. Color arrows show lithium flow for reactor startup and operation. Flow reversed for shutdown. Conceived for use aboard spacecraft, actuator principle applied to terrestrial hydraulic machinery involving motion of ganged rods.

Gangs, Marginalised Youth and Social Capital

ERIC Educational Resources Information Center

Deuchar, Ross

2009-01-01

Adolescents are routinely demonised by politicians and the media.Ross Deuchar's compelling research into the views of some of the toughest--youths who are growing up in socially deprived urban areas of Glasgow in Scotland--reveals the true facts. They talked to him about their lives, gang culture and territorialiity and he passes on their words…

Man-made climatic changes in the Ganges basin

NASA Astrophysics Data System (ADS)

Adel, Miah M.

2002-06-01

Climate data pertaining to the Ganges basin in Bangladesh were analysed to find any climatic changes in the wake of the upstream water diversion by the Farakka Barrage. Whereas the diversions have been continuing from at least 30 international rivers upstream of Bangladesh, the diversion from the Ganges is the best known and has a wider coverage than all other diversions. The diversion reduced the Ganges' discharge through the delta by about 60% from a pre-diversion average value of 1932 m3 s-1, decreased water availability in flood plains, ponds, canals, and ditches by about 50%, dropped the groundwater table, and caused changes in surface features. It took about 5 years of diversions beyond the test run year of 1975 for the environment to react to set 1981 as the baseline year. During the post-baseline era: (1) heating degree days and cooling degree days were respectively 1.33 and 1.44 times more than their counterparts during the pre-baseline era; (2) the summertime and wintertime average temperatures were respectively 1 °C more and 0.5 °C less than the corresponding values during the pre-baseline era; (3) the mode 32 °C of summertime maximum temperatures was 1 °C higher and occurred 414 times more, and the mode 25 °C of wintertime temperature was 1 °C less and occurred 17 times less than the corresponding quantities during the pre-baseline era; (4) the average value of maximum relative humidity has increased by more than 2% and that of minimum relative humidity has dropped by the same amount; (5) the mode 95% and 70% of maximum and minimum relative humidity values have occurred 1322 times and 84 times more respectively than their pre-baseline counterparts; and (6) the frequency for 100 mm or more rainfall and the monthly average rainfalls have dropped by about 50% and 30% respectively. The solution to the climatic changes lies in the restoration of the virgin Ganges flow, dredging of the Ganges and its distributaries to remove shoals and siltation, and re

Potential 2001 Landing Sites in Melas Chasma, Mars

NASA Technical Reports Server (NTRS)

Weitz, C. M.; Lucchitta, B. K.; Chapman, M. G.

1999-01-01

We have selected four areas in Valles Marineris as potential landing sites for the 2001 mission. After 20 years of analyses, the formation of the Valles Marineris system of troughs and its associated deposits still has not been sufficiently explained. They could have formed by collapse, as tectonic grabens, or in two stages involving ancestral collapse basins later cut by grabens. Understanding all aspects of the Valles Marineris, in particular the interior layered deposits, would significantly contribute to deciphering the internal and external history of Mars. The deposits have been postulated to be remnants of wall rock, lacustrine deposits, mass wasting deposits, eolian deposits, carbonate deposits, or volcanic deposits. Because an understanding of the formation of Valles Marineris and its interior deposits is so important to deciphering the history of Mars, we have proposed landing sites for the 2001 mission on flat shelves of interior deposits in Melas Chasma.

Closer to Guns: the Role of Street Gangs in Facilitating Access to Illegal Firearms.

PubMed

Roberto, Elizabeth; Braga, Anthony A; Papachristos, Andrew V

2018-05-09

Criminal offenders often turn to social networks to gain access to firearms, yet we know little about how networks facilitate access to firearms. This study conducts a network analysis of a co-offending network for the City of Chicago to determine how close any offender may be to a firearm. We use arrest data to recreate the co-offending network of all individuals who were arrested with at least one other person over an eight-year period. We then use data on guns recovered by the police to measure potential network pathways of any individual to known firearms. We test the hypothesis that gangs facilitate access to firearms and the extent to which such access relates to gunshot injury among gang members. Findings reveal that gang membership reduces the potential network distance (how close someone is) to known firearms by 20% or more, and regression results indicate that the closer gang members are to guns, the greater their risk of gunshot victimization.

Coprates Chasma Landslides in IR

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site]

Today's daytime IR image is of a portion of Coprates Chasma, part of Valles Marineris. As with yesterday's image, this image shows multiple large landslides.

Image information: IR instrument. Latitude -8.2, Longitude 300.2 East (59.8 West). 100 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Comparing the Criminal Behavior of Youth Gangs and At-Risk Youths. Research in Brief.

ERIC Educational Resources Information Center

Huff, C. Ronald

A study was conducted to compare the criminal behavior of gang members and nongang at-risk youths in four urban and suburban communities, Denver (Colorado), Aurora (Colorado), Broward County (Florida), and Cleveland (Ohio). The first three communities were emergent, rather than chronic, gang environments, but in Cleveland, information on gangs…

Can Education Play a Role in the Prevention of Youth Gangs in Indian Country? One Tribe's Approach. ERIC Digest.

ERIC Educational Resources Information Center

Hernandez, Arturo

Traditionally an urban problem, gang involvement is growing on Native American reservations. This digest examines common factors in gang development and one tribe's response through a Native-centric education and juvenile justice system. The sum of handicaps associated with gang involvement has been termed "multiple marginality," and…

Dataset on Investigating the role of onsite learning in the optimisation of craft gang's productivity in the construction industry.

PubMed

Ugulu, Rex Asibuodu; Allen, Stephen

2017-12-01

The data presented in this article is an original data on "Investigating the role of onsite learning in the optimisation of craft gang's productivity in the construction industry". This article describes the constraints influencing craft gang's productivity and the influence of onsite learning on the blockwork craft gang's productivity. It also presented the method of data collection, using a semi-structured interview and an observation method to collect data from construction organisations. We provided statistics on the top most important constraints affecting the craft gang's productivity using 3-D Bar charts. In addition, we computed the correlation coefficients and the regression model on the influence of onsite learning on craft gang's productivity using the man-hour as the dependent variable. The relationship between blockwork inputs and cycle numbers was determined at 5% significance level. Finally, we presented data information on the application of the learning curve theory using the unit straight-line model equations and computed the learning rate of the observed craft gang's blockwork repetitive work.

"Deterrability" among Gang and Nongang Juvenile Offenders: Are Gang Members More (or Less) Deterrable than Other Juvenile Offenders?

ERIC Educational Resources Information Center

Maxson, Cheryl L.; Matsuda, Kristy N.; Hennigan, Karen

2011-01-01

This study investigates the effect of the threat of legal sanctions on intentions to commit three types of offenses with a representative sample of 744 officially adjudicated youth with varying histories of offenses and gang involvement. In a departure from previous research, the authors find small severity effects for property crimes that are not…

Stemming the Growth: Exploring the Risk Factors in Group Membership in Domestic Street Gangs and Foreign Terrorist Organizations

DTIC Science & Technology

2015-09-01

attempt to explain gang membership and offending and delinquent behavior. New CVE program developers may be able to use these same theories to help...outcome in question—in this case, gang membership. Gang research scholars have discovered a multitude of risk factors that are statistically linked...and offending and delinquent behavior, including cultural diffusion, differential association, social disorganization and strain theory. CVE program

Drug-scene familiarity and exposure to gang violence among residents in a rural farming community in Baja California, Mexico

PubMed Central

Volkmann, Tyson; Fraga, Miguel A.; Brodine, Stephanie K.; Iñiguez-Stevens, Esmeralda; Cepeda, Alice; Elder, John P.; Garfein, Richard S.

2012-01-01

We examined drug-scene familiarity and exposure to gang violence among residents of a migrant farming community in rural Baja California, Mexico. In October 2010, 164 members of a single colonia (community) underwent an interviewer-administered survey to assess ‘exposure to gang violence’ and ‘drug-scene familiarity’, as well as other health indicators. Logistic regression was used to identify correlates of exposure to gang violence. Overall, 20% of participants were male, the median age was 27 years, 24% spoke an indigenous language, 42% reported exposure to gang violence, and 39% reported drug-scene familiarity. Factors independently associated with exposure to gang violence included being younger (AOR=0.80 per 5-year increase, 95% CI=0.67–0.96), living in the community longer (AOR=1.47 per 5-year increase, 95% CI=1.11–1.72), higher educational attainment (AOR=1.70 per 5-year increase, 95% CI=1.07–1.12), and drug-scene familiarity (AOR=5.10, 95%CI=2.39–10.89). Exposure to gang violence was very common in this community and was associated with drug-scene familiarity, suggesting a close relationship between drugs and gang violence in this rural community. In a region characterised by mass migration from poorer parts of Mexico, where drugs and gangs have not been previously reported, emerging social harms may affect these communities unless interventions are implemented. PMID:23072623

The effect of urban street gang densities on small area homicide incidence in a large metropolitan county, 1994-2002.

PubMed

Robinson, Paul L; Boscardin, W John; George, Sheba M; Teklehaimanot, Senait; Heslin, Kevin C; Bluthenthal, Ricky N

2009-07-01

The presence of street gangs has been hypothesized as influencing overall levels of violence in urban communities through a process of gun-drug diffusion and cross-type homicide. This effect is said to act independently of other known correlates of violence, i.e., neighborhood poverty. To test this hypothesis, we independently assessed the impact of population exposure to local street gang densities on 8-year homicide rates in small areas of Los Angeles County, California. Homicide data from the Los Angeles County Coroners Office were analyzed with original field survey data on street gang locations, while controlling for the established covariates of community homicide rates. Bivariate and multivariate regression analyses explicated strong relationships between homicide rates, gang density, race/ethnicity, and socioeconomic structure. Street gang densities alone had cumulative effects on small area homicide rates. Local gang densities, along with high school dropout rates, high unemployment rates, racial and ethnic concentration, and higher population densities, together explained 90% of the variation in local 8-year homicide rates. Several other commonly considered covariates were insignificant in the model. Urban environments with higher densities of street gangs exhibited higher overall homicide rates, independent of other community covariates of homicide. The unique nature of street gang killings and their greater potential to influence future local rates of violence suggests that more direct public health interventions are needed alongside traditional criminal justice mechanisms to combat urban violence and homicides.

Life-Course Events, Social Networks, and the Emergence of Violence among Female Gang Members

ERIC Educational Resources Information Center

Fleisher, Mark S.; Krienert, Jessie L.

2004-01-01

Using data gathered from a multi-year field study, this article identifies specific life-course events shared by gang-affiliated women. Gangs emerge as a cultural adaptation or pro-social community response to poverty and racial isolation. Through the use of a social-network approach, data show that violence dramatically increases in the period…

A modified predator-prey model for the interaction of police and gangs.

PubMed

Sooknanan, J; Bhatt, B; Comissiong, D M G

2016-09-01

A modified predator-prey model with transmissible disease in both the predator and prey species is proposed and analysed, with infected prey being more vulnerable to predation and infected predators hunting at a reduced rate. Here, the predators are the police and the prey the gang members. In this system, we examine whether police control of gangs is possible. The system is analysed with the help of stability analyses and numerical simulations. The system has five steady states-four of which involve no core gang members and one in which all the populations coexist. Thresholds are identified which determine when the predator and prey populations survive and when the disease remains endemic. For parameter values where the spread of disease among the police officers is greater than the death of the police officers, the diseased predator population survives, when it would otherwise become extinct.

A modified predator–prey model for the interaction of police and gangs

PubMed Central

Sooknanan, J.; Bhatt, B.

2016-01-01

A modified predator–prey model with transmissible disease in both the predator and prey species is proposed and analysed, with infected prey being more vulnerable to predation and infected predators hunting at a reduced rate. Here, the predators are the police and the prey the gang members. In this system, we examine whether police control of gangs is possible. The system is analysed with the help of stability analyses and numerical simulations. The system has five steady states—four of which involve no core gang members and one in which all the populations coexist. Thresholds are identified which determine when the predator and prey populations survive and when the disease remains endemic. For parameter values where the spread of disease among the police officers is greater than the death of the police officers, the diseased predator population survives, when it would otherwise become extinct. PMID:27703682

Mono- and Polyhydrated Sulfates in Tithonium Chasma

NASA Technical Reports Server (NTRS)

2008-01-01

This image of sulfate-containing deposits in Tithonium Chasma was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at 1538 UTC (11:38 a.m. EDT) on August 31, 2007 near 5.22 degrees south latitude, 270.48 degrees east longitude. CRISM's image was taken in 544 colors covering 0.36-3.92 micrometers, and shows features as small as 40 meters (132 feet) across. The region covered is just over 10 kilometers (6.2 miles) wide at its narrowest point.

Tithonium Chasma lies at the western end of the Valles Marineris canyon system. It extends approximately east-west for roughly 810 kilometers (503 miles), varies in width from approximately 10 to 110 kilometers (6 to 68 miles), and cuts into the Martian surface to a maximum depth of roughly 6 kilometers (4 miles).

The top panel in the montage above shows the location of the CRISM image on a mosaic taken by the Mars Odyssey spacecraft's Thermal Emission Imaging System (THEMIS). The CRISM data covers an area centered on a ridge of erosion-resistant rock.

The center left image, an infrared false color image, reveals banded, light-colored material draped on the ridge. The center right image unveils the mineralogical composition of the area, with yellow representing monohydrated sulfates (sulfates with one water molecule incorporated into each molecule of the mineral) and purple polyhydrated sulfates (sulfates with multiple waters per mineral molecule).

The lower two images are renderings of data draped over topography with 7 times vertical exaggeration. These images provide a view of the topography and reveal how the sulfate deposits both cover and flank the ridge. Brighter, monohydrated sulfate (yellow) deposits revealed in the lower right image lies along the ridge's northwest side and fall off into a small valley or depression, while darker polyhydrated sulfates (purple) lie along the ridge's northeast flank. A deposit of both mono- and polyhydrated sulfates spanning the ridge

[Rape by 2 assaillants and gang rape in Montreal].

PubMed

Lamontagne, Y; Boyer, R; Lamontagne, C; Giroux, J

1984-11-01

A survey was conducted in 230 cases of rape and rape attempts heard in the Judicial District of Montreal between January 1975 and May 1978. Data were compiled from the 30 assaults including two or more assaillants. Results show that in cases of rape committed by two men the aggressors are older than gang rapists, meet the victim mainly in her flat or in a bar, and rape her in her own home, in a car or a hotel. In these cases, voyeurism seems to be an important factor since, most of the time, rape is committed by only one of the two aggressors. On the other hand, gang rapists are younger, meet the victim in public places, on the street or when she is hitch-hiking and attack her in one of the aggressors' house, in public places or on the street. Exhibitionism seems more present in this group of rapists. For both groups the victims are mainly single, younger than the aggressors and have diverse occupations. Finally, regarding the legal outcome half of the subjects were liberated or acquitted in both groups. Rape committed by two men had never been studied or compared with gang rape up until now. Results of this survey show dynamic and demographic differences between these two groups of sexual delinquents.

Street Gangs Are Big Business--And Growing.

ERIC Educational Resources Information Center

Harrington-Lueker, Donna

1990-01-01

Highlights findings from a study by Irving Spergel of gang activity in 45 cities. Ronald Stephen, executive director of the National School Safety Center, cites an increase in drug-marketing and violence and advises educators to be aware of what is going on, establish rapport with community groups, and enlist the support of students. (MLF)

Interagency Collaboration with High-Risk Gang Youth.

ERIC Educational Resources Information Center

Okamoto, Scott K.

This article describes the results of a study on interagency collaboration required to make major systemic changes in order to address the needs of emotionally and behaviorally disturbed youth. Interviews were conducted with practitioners from a cross-section of agencies that worked with high-risk gang youth. The intent was to examine both the…

Gangs of Chicago: Perceptions of crime and its effect on the recreation behavior of Latino residents in urban communities

Treesearch

Monika Stodolska; Juan Carlos Acevedo; Kimberly J. Shinew

2009-01-01

Perception of safety is an important factor affecting the leisure behavior of Latinos residing in urban neighborhoods. Yet research on how fear of crime and fear of gangs in particular affect leisure of ethnic and racial minorities is underdeveloped. The objectives of this study are to examine how gangs operate in recreation spaces in Latino neighborhoods, how gangs...

Substance Abuse among Juvenile Delinquents and Gang Members. Prevention Research Update Number Six, Spring 1990.

ERIC Educational Resources Information Center

Pollard, John A.; Austin, Gregory A.

There is a strong statistical correlation between delinquency activity level and the level of alcohol and other drug (AOD) use in adolescents. A strong association between drug use, drug trafficking, and youth gangs has also emerged. However, several important questions concerning the relationship of delinquency, gang membership, and AOD use…

THE PATH AND PROMISE OF FATHERHOOD FOR GANG MEMBERS

PubMed Central

Moloney, Molly; MacKenzie, Kathleen; Hunt, Geoffrey; Joe-Laidler, Karen

2009-01-01

While an increase in research on criminal desistance has occurred in recent years, little research has been applied to the gang field. Using qualitative interview data, this article examines fatherhood as a potential turning point in the lives of 91 gang members in the San Francisco Bay Area. Fatherhood initiated important subjective and affective transformations that led to changes in outlook, priorities and future orientation. However, these subjective changes were not sufficient unless accompanied by two additional features: first, changes in the amount of time spent on the streets and, second, an ability to support oneself or one’s family with legal income. Though fatherhood is no panacea, becoming a father did act as an important turning point toward desistance and motivator for change for some. PMID:20046970

Geologic map of the Hecate Chasma quadrangle (V-28), Venus

USGS Publications Warehouse

Stofan, Ellen R.; Guest, John E.; Brian, Antony W.

2012-01-01

The overall topography of V–28 consists of plains located slightly below mean planetary radius (MPR, 6051.84). The lowest regions are found in the rift trough (3.3 m below MPR), and the highest along the rift rim (4.3 km above MPR). The regions that are the roughest at Magellan radar wavelengths in the quadrangle occur along Hecate Chasma (root mean square [rms] slopes >10°), with most regions being relatively smooth (roughnesses comparable to the average Venus surface value of 2.84°). Emissivity values in the quadrangle are typical of most venusian plains regions, with a range in values for the quadrangle of 0.68–0.91. The highest emissivity values in the quadrangle lie at the highest elevations in the quadrangle (corona rims and interiors).

Literacy and Advocacy in Adolescent Family, Gang, School, and Juvenile Court Communities: "Crip 4 Life"

ERIC Educational Resources Information Center

Smith, Debra; Whitmore, Kathryn F.

2006-01-01

The goal of this book is to encourage educators and researchers to understand the complexities of adolescent gang members' lives in order to rethink their assumptions about these students in school. The particular objective is to situate four gang members as literate, caring students from loving families whose identities and literacy keep them on…

Multiculturalism as a Policy for Disarming Gang Violence in Communities at Large and in Schools.

ERIC Educational Resources Information Center

Clark, Christine; Jenkins, Morris

Those who try to deal with violence in U.S. communities and schools have tended to concentrate on suppression of violence, rather than real prevention, particularly as violence is associated with youth gangs. This discussion focuses on multiculturalism as a policy for reducing gang violence, rather than strategies that have been used to deal with…

Brief Report: Do Delinquency and Community Violence Exposure Explain Internalizing Problems in Early Adolescent Gang Members?

ERIC Educational Resources Information Center

Madan, Anjana; Mrug, Sylvie; Windle, Michael

2011-01-01

Adolescent gang members are at higher risk for internalizing problems as well as exposure to community violence and delinquency. This study examined whether gang membership in early adolescence is associated with internalizing problems (depression, anxiety, and suicidal behavior) and whether these associations are mediated by delinquency and…

Morphology and geology of the ILD in Capri/Eos Chasma (Mars) from visible and infrared data

NASA Astrophysics Data System (ADS)

Flahaut, Jessica; Quantin, Cathy; Allemand, Pascal; Thomas, Pierre

2010-05-01

Layered deposits have been observed in different locations at the surface of Mars, as crater floors and canyons systems. Their high interest relies in the fact they imply dynamical conditions in their deposition medium. Indeed, in opposition to most of the rocks of the martian surface, which have a volcanic origin, bright layered deposits seems to be sedimentary outcrops. Capri Chasma, a canyon located at the outlet of Valles Marineris, exhibits such deposits called Interior Layered Deposits (ILD). A large array of visible and infrared spacecraft data were used to build a Geographic Information System (GIS). We added HiRiSE images, from the recent MRO mission, which offer a spatial resolution of 25 cm per pixel. It allowed the mapping and the analysis of morphologies in the canyon. We highlighted that the ILD are several kilometers thick and flat-top stratified deposits. They overlap the chaotic floor. They are surrounded and cut by several flow features that imply that liquid water was still acting after the formation of these stratified deposits. The density of crater on the floor of Capri Chasma was quantified. The current topography was aged to 3 Gyr. All these morphological information allow us to suggest a plausible geological history for Capri Chasma. We propose that the Interior Layered Deposits have formed during the Hesperian, during or after the opening of the canyon. Some observations argue that water discharges have happened at several times before and just after the formation of the ILD. Liquid water must have played a major role in the formation of these deposits after 3.5 Gyr, implying that it was present in surface at least locally and temporarily. If this can be applied to ILD in others canyons of Valles Marineris, it would imply that liquid water was stable in surface or sub-surface during the Hesperian. Or in the actual conditions, with a cold and dry martian surface, long-term standing water bodies are not possible. Thus we suggest that either

Target Transformation Constrained Sparse Unmixing (ttcsu) Algorithm for Retrieving Hydrous Minerals on Mars: Application to Southwest Melas Chasma

NASA Astrophysics Data System (ADS)

Lin, H.; Zhang, X.; Wu, X.; Tarnas, J. D.; Mustard, J. F.

2018-04-01

Quantitative analysis of hydrated minerals from hyperspectral remote sensing data is fundamental for understanding Martian geologic process. Because of the difficulties for selecting endmembers from hyperspectral images, a sparse unmixing algorithm has been proposed to be applied to CRISM data on Mars. However, it's challenge when the endmember library increases dramatically. Here, we proposed a new methodology termed Target Transformation Constrained Sparse Unmixing (TTCSU) to accurately detect hydrous minerals on Mars. A new version of target transformation technique proposed in our recent work was used to obtain the potential detections from CRISM data. Sparse unmixing constrained with these detections as prior information was applied to CRISM single-scattering albedo images, which were calculated using a Hapke radiative transfer model. This methodology increases success rate of the automatic endmember selection of sparse unmixing and could get more accurate abundances. CRISM images with well analyzed in Southwest Melas Chasma was used to validate our methodology in this study. The sulfates jarosite was detected from Southwest Melas Chasma, the distribution is consistent with previous work and the abundance is comparable. More validations will be done in our future work.

Understanding Violence in Contemporary and Earlier Gangs: An Exploratory Application of the Theory of Reasoned Action.

ERIC Educational Resources Information Center

Evans, Judy P.; Taylor, Jerome

1995-01-01

Reviews the theory of reasoned action to demonstrate how it can be applied to understanding gang violence, and illustrates its potential applicability to a pilot sample of 30 contemporary and 18 earlier gangs living in a large metropolitan community. Results indicate this theory has been helpful in explaining higher levels of violence in…

Evaluation and Evolution of the Gang Resistance Education and Training (G.R.E.A.T.) Program

ERIC Educational Resources Information Center

Esbensen, Finn-Aage; Peterson, Dana; Taylor, Terrance J.; Freng, Adrienne; Osgood, D. Wayne; Carson, Dena C.; Matsuda, Kristy N.

2011-01-01

The Gang Resistance Education and Training (G.R.E.A.T.) program is a gang- and delinquency-prevention program delivered by law enforcement officers within a school setting. Originally designed in 1991 by Phoenix-area law enforcement agencies to address local needs, the program quickly spread across the United States. In this article, we describe…

Contribution of Sediment Compaction/Loading to the Ganges-Bangladesh Delta Subsidence

NASA Astrophysics Data System (ADS)

Karpytchev, Mikhail; Krien, Yann; Ballu, Valerie; Becker, Melanie; Calmant, Stephane; Spada, Giorgio; Guo, Junyi; Khan, Zahirul; Shum, Ck

2016-04-01

A pronounced spatial variability characterizes the subsidence/uplift rates in the Ganges-Bangladesh delta estimated from both sediment cores and modern geodetic techniques. The large variability of the subsidence rates suggests an interplay of different natural and anthropogenic processes including tectonics, sediment loading and sediment compaction, groundwater extaction among many others drivers of the delta vertical land movements.In this study, we focus on estimating the subsidence rates due to the sediments transported by the Ganges-Brahmaputra since the last 18 000 years. The delta subsidence induced by the sediment loading and the resulting sea level changes are modelled by the TABOO and SELEN software (Spada, 2003; Stocchi and Spada, 2007) in the framework of a gravitationally self-consistent Earth model. The loading history was obtained from available sediment cores and from the isopach map of Goodbread and Kuehl (2000). The results demonstrate that the delta loading enhanced by the Holocene sedimention can be responsable for a regular subsidence across the Ganges-Brahmaputra delta with an amplitude of 1-5 mm/yr along the Bengal coast. These estimates demonstrate that the contribution of the Holocene as well as modern sediment loading should be taken into account in climate change mitigation politicy for Bangladesh.

Gender Norms and Age-Disparate Sexual Relationships as Predictors of Intimate Partner Violence, Sexual Violence, and Risky Sex among Adolescent Gang Members.

PubMed

Nydegger, Liesl A; DiFranceisco, Wayne; Quinn, Katherine; Dickson-Gomez, Julia

2017-04-01

Unequal gender norms and age-disparate sexual relationships can lead to power imbalances and are also associated with intimate partner violence (IPV), sexual coercion and violence, and sexual risk behaviors. The present study examined these variables from both victim and perpetrator perspectives among adolescent gang members. Age-disparate sexual relationships were defined as sex partners 5 or more years older among female participants and 5 or more years younger among male participants. Participants were recruited from a mid-sized Midwestern city and completed a 60-90-min audio computer-assisted self-interview in a community-based setting. Participants in this study included 107 female gang members (68 % African-American, 19 % Latina; mean age, 17.6) and 169 male gang members (62 % African-American, 28 % Latino; mean age, 17.7). As hypothesized, endorsing unequal gender norms toward women was significantly related to IPV victimization among female participants and perpetration among male participants, and engagement in group sex in the past month among both female and male participants (ps < 0.05). Additionally, unequal gender norms were significantly related to male participants' perpetrating rape (p < 0.05). As hypothesized, female gang members who had been in age-disparate sexual relationships were significantly more likely to have experienced more IPV and report being raped and males gang members who had age-disparate sexual relationships were significantly more likely to perpetrate IPV in the past year and perpetrate rape (ps < 0.05). Age-disparate sexual relationships were also significantly related to being gang raped among female gang members and participating in a gang rape among male gang members, and engaging in group sex among both female and male gang members (ps < 0.05). Female participants who had been in age-disparate sexual relationships were more likely to have been pregnant (ps < 0.05). It is essential for researchers and

Gang Membership, School Violence, and the Mediating Effects of Risk and Protective Behaviors in California High Schools

ERIC Educational Resources Information Center

Estrada, Joey Nuñez, Jr.; Gilreath, Tamika D.; Astor, Ron Avi; Benbenishty, Rami

2014-01-01

There is insufficient empirical evidence exploring associations between gang membership and school violence behaviors. Using a sample of 272,863 high school students, this study employs a structural equation model to examine how school risk and protective behaviors and attitudes mediate effects of gang members' involvement with school violence…

Gangs and Guerrillas: Ideas from Counterinsurgency and Counterterrorism

DTIC Science & Technology

2011-03-01

13. SUPPLEMENTARY NOTES 14. ABSTRACT In a discussion at the Naval Postgraduate School in Monterey, California, it became apparent that there were...Lieutenant Commander, US Navy, Masters Student in the Defense Analysis Department, Naval Postgraduate School Hy Rothstein, Senior Lecturer, Defense...NPS-DA-11-001 NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA GANGS AND GUERRILLAS: Ideas from Counterinsurgency And Counterterrorism Edited

Candor Exposed

NASA Image and Video Library

2006-05-19

This MOC image shows outcrops of light-toned rock, interpreted to be sedimentary in origin, in east Candor Chasma. The exposures of light-toned rock are separated by areas of windblown ripples and dark sand

Enabling Prosecutors To Address Drug, Gang, and Youth Violence. Juvenile Accountability Incentive Block Grants (JAIBG) Program Bulletin.

ERIC Educational Resources Information Center

Gramckow, Heike P.; Tompkins, Elena

This bulletin offers data on recent trends in juvenile violence, juvenile drug offenses, and gang-related juvenile offending, and describes prosecutorial responses to such offenses. Examples of promising prosecutor-led programs combating the illicit use of guns, violence, drugs, and gangs are also provided. These examples provide a range of ideas…

Dual Trajectories of Gang Affiliation and Delinquent Peer Association during Adolescence: An Examination of Long-Term Offending Outcomes

PubMed Central

Krohn, Marvin D.

2018-01-01

Prior research has demonstrated that both adolescent gang affiliation and perceived delinquent peer association are important predictors of individual offending. A crucial question is whether and how youth gang affiliation contributes to a spectrum of criminal acts above and beyond the influence of associating with delinquent peers. Using 14 waves of data from the Rochester Youth Developmental Study, an ongoing longitudinal panel study aimed at understanding the causes and consequences of delinquency and drug use in an urban sample of adolescents, the current study employs a relatively new modeling technique—dual trajectory analysis—to illustrate the dynamic relationship between these two measures among 666 male youth. The results suggest that the two measures, while overlapping, may constitute distinct concepts that operate in different ways. The most convincing evidence of gang effects, above and beyond the influence of perceived peer delinquency, is for violent behavior and by extension police arrest. Our findings contribute to developmental research and provide information that informs future gang control efforts. PMID:26748922

Geologic Map of the Diana Chasma Quadrangle (V-37), Venus

USGS Publications Warehouse

Hansen, V.L.; DeShon, H.R.

2002-01-01

Diana Chasma quadrangle hosts some of the steepest topography on Venus. Altimetry measurements range from -2.5 to 4.7 km (0.0 = mean planetary radius), with a surface mean of 0.6 km. Fractures and faults within the central fracture/rift zone create large blocks of down-dropped material, especially along the east-central edge of the map area. The Dali and Diana chasmata display slopes of >30°, the steepest and deepest trenches on Venus. Both chasmata host landslide deposits presumably sourced from the steep chasmata walls. The tessera inlier, coronae, and ridge belts sit topographically above Rusalka and Zhibek planitiae. Rusalka Planitia topography describes broad undulations having northwest-trending ridges spaced ~200 km apart. The most distinctive ridge, Vetsorgo Dorsum, centered at 6.5° S., 163° E., is a Class I ridge belt owing to its simple arch morphology. The central interior of Markham crater sits topographically lower than the surrounding region, which slopes downward to the east.

Light-Toned Bedrock Along Cracks as Evidence of Fluid Alteration

NASA Image and Video Library

2007-02-15

This enhanced-color image from the HiRISE camera on NASA Mars Reconnaissance Orbiter shows a landscape of sand dunes and buttes among a background of light-toned bands and dark-toned bands in the Candor Chasma region

Clinical Issues in the Treatment of Chicano Male Gang Youth.

ERIC Educational Resources Information Center

Belitz, Jerald; Valdez, Diana

1994-01-01

Critical factors in the behavior of Chicano gang youth are family disintegration, cultural dissolution, abusive family relationships, and histories of interpersonal violence. Specific treatment modalities (individual, family, group) are discussed, and the importance of a multimodal approach is emphasized. Case studies highlight family dynamics and…

Commitment language and homework completion in a behavioral employment program for gang-affiliated youth.

PubMed

Smith, Caitlin; Huey, Stanley J; McDaniel, Dawn D

2015-05-01

Research with substance-abusing samples suggests that eliciting commitment language during treatment may improve motivation to change, increase treatment engagement, and promote positive treatment outcomes. However, the relationship between in-session client language and treatment success is not well-understood for youth offender populations. This study evaluated the relationship between commitment language, treatment engagement (i.e., homework completion), and weekly employment outcomes for six gang-affiliated juvenile offenders participating in an employment counseling intervention. Weekly counseling sessions were audio-recorded, transcribed, and coded for commitment language strength. Multilevel models were fit to the data to examine the relationship between commitment language and counseling homework or employment outcomes within participants over time. Commitment language strength predicted subsequent homework completion but not weekly employment. These findings imply that gang-affiliated delinquent youth who express motivation to change during employment counseling will be more likely to comply with counselor-initiated homework. Further research on counselor techniques for promoting commitment language among juvenile gang offenders is needed. © The Author(s) 2013.

Prioritizing parts from cutting bills when gang-ripping first

Treesearch

R. Edward Thomas

1996-01-01

Computer optimization of gang-rip-first processing is a difficult problem when working with specific cutting bills. Interactions among board grade and size, arbor setup, and part sizes and quantities greatly complicate the decision making process. Cutting the wrong parts at any moment will mean that more board footage will be required to meet the bill. Using the ROugh...

Mediating the Maltreatment-Delinquency Relationship: The Role of Triad Gang Membership.

PubMed

Chui, Wing Hong; Khiatani, Paul Vinod

2018-02-01

The primary aim of this article is to examine the role of triad affiliation in mediating the relationship between child maltreatment (neglect, punishment, emotional abuse, and sexual abuse) and delinquency among active young gang members in Hong Kong. A sample of 177 gang members aged 12 to 24 was recruited to complete a questionnaire with the assistance of a youth outreach social work team. Neglect was identified as the most common form of maltreatment, followed by emotional abuse, punishment, and sexual abuse. Mediation analyses confirmed that triad affiliation acts as a mediating variable in the child maltreatment-delinquency relationship, except in cases of sexual abuse. Only the relationship between punishment and delinquency was found to be fully mediated by triad affiliation; partial mediation effects were found for neglect and emotional abuse. Recommendations for child protection and youth workers are provided.

Yield comparisons from floating blade and fixed arbor gang ripsaws when processing boards before and after crook removal

Treesearch

Charles J. Gatchell; Charles J. Gatchell

1991-01-01

Gang-ripping technology that uses a movable (floating) outer blade to eliminate unusable edgings is described, including new tenn1nology for identifying preferred and minimally acceptable strip widths. Because of the large amount of salvage required to achieve total yields, floating blade gang ripping is not recommended for boards with crook. With crook removed by...

Mission Impossible? Social Work Practice with Black Urban Youth Gangs.

ERIC Educational Resources Information Center

Fox, Jerry R.

1985-01-01

Describes the adaptation of social work practice skills to serve black urban youth gangs. Presents a model for practice which respects youths' right to self-determination and community needs. Model stages discussed include contact, rapport, setting goals, assigning roles, procuring resources, and evaluation. Model applicability is suggested. (NRB)

"American" Abjection: "Chicanos," Gangs, and Mexican/Migrant Transnationality in Chicago

ERIC Educational Resources Information Center

De Genova, Nicholas

2008-01-01

Crime and street violence often evoke racialized discourses about urban space. In this ethnographic research in Chicago, however, the disdain that many Mexican migrants articulated about street gangs principally concerned issues "internal" to the Mexican/Chicano community, notably a profound ambivalence about U.S.-born Mexicans and a…

Development of seasonal flow outlook model for Ganges-Brahmaputra Basins in Bangladesh

NASA Astrophysics Data System (ADS)

Hossain, Sazzad; Haque Khan, Raihanul; Gautum, Dilip Kumar; Karmaker, Ripon; Hossain, Amirul

2016-10-01

Bangladesh is crisscrossed by the branches and tributaries of three main river systems, the Ganges, Bramaputra and Meghna (GBM). The temporal variation of water availability of those rivers has an impact on the different water usages such as irrigation, urban water supply, hydropower generation, navigation etc. Thus, seasonal flow outlook can play important role in various aspects of water management. The Flood Forecasting and Warning Center (FFWC) in Bangladesh provides short term and medium term flood forecast, and there is a wide demand from end-users about seasonal flow outlook for agricultural purposes. The objective of this study is to develop a seasonal flow outlook model in Bangladesh based on rainfall forecast. It uses European Centre for Medium-Range Weather Forecasts (ECMWF) seasonal precipitation, temperature forecast to simulate HYDROMAD hydrological model. Present study is limited for Ganges and Brahmaputra River Basins. ARIMA correction is applied to correct the model error. The performance of the model is evaluated using coefficient of determination (R2) and Nash-Sutcliffe Efficiency (NSE). The model result shows good performance with R2 value of 0.78 and NSE of 0.61 for the Brahmaputra River Basin, and R2 value of 0.72 and NSE of 0.59 for the Ganges River Basin for the period of May to July 2015. The result of the study indicates strong potential to make seasonal outlook to be operationalized.

Frost-covered dunes

NASA Technical Reports Server (NTRS)

1999-01-01

MOC image of dunes in Chasma Boreale, a giant trough in the north polar cap. This September 1998 view shows dark sand emergent from beneath a veneer of bright frost left over from the northern winter that ended in July 1998.

Leaving Gangs Behind to Live Parables of Kinship.

PubMed

Steiner, Mary Ann

2016-07-01

Fr. Gregory Boyle, SJ, founder and executive director of Homeboy Industries in Los Angeles, can move an audience to tears. He doesn't get that result with the distressing accounts of individuals whose gang activities sank them to harrowing depths. He does it with simple descriptions of how some of those men and women manage to climb rungs of unconditional love to return to their rightful place in the eyes of God.

Bedrock and structural geologic maps of eastern Candor Sulci, western Ceti Mensa, and southeastern Ceti Mensa, Candor Chasma, Valles Marineris region of Mars

USGS Publications Warehouse

Okubo, Chris H.; Gaither, Tenielle A.

2017-05-12

This map product contains a set of three 1:18,000-scale maps showing the geology and structure of study areas in the western Candor Chasma region of Valles Marineris, Mars. These maps are part of an informal series of large-scale maps and map-based topical studies aimed at refining current understanding of the geologic history of western Candor Chasma. The map bases consist of digital elevation models and orthorectified images derived from High Resolution Imaging Science Experiment (HiRISE) data. These maps are accompanied by geologic cross sections, colorized elevation maps, and cutouts of HiRISE images showing key superposition relations. Also included in this product is a Correlation of Map Units that integrates units across all three map areas, as well as an integrated Description of Map Units and an integrated Explanation of Map Symbols. The maps were assembled using ArcGIS software produced by Environmental Systems Research Institute (http://www.esri.com). The ArcGIS projects and databases associated with each map are included online as supplemental data.

Motivations for Gang Membership in Lagos, Nigeria: Challenge and Resilience

ERIC Educational Resources Information Center

Salaam, Abeeb Olufemi

2011-01-01

The current study explores the major challenges (in the form of risk factors) that may influence unemployed youths' involvement in gang and criminal activity in Lagos, Nigeria. A combination of techniques (e.g., oral, in-depth interviews, and questionnaires) were used for the data collection. The computed outcomes establish some of the major…

Functions of Aggression and Delinquency: The Moderating Role of Parent Criminality and Friends' Gang Membership.

PubMed

Ang, Rebecca P; Huan, Vivien S; Li, Xiang; Chan, Wei Teng

2016-03-02

This study examined the relationships between two functions of aggression (i.e., reactive and proactive) and delinquency, including the moderating effects of parent criminality and friends' gang membership, in a sample of 1,027 Singaporean adolescents from Grade 7 to Grade 9, with age ranging from 12 to 19 years (M = 14.10, SD = 1.15). Findings suggested that both reactive aggression and proactive aggression significantly and positively predicted delinquency (after controlling for proactive aggression and reactive aggression, respectively), with proactive aggression being a stronger predictor. Friends' gang membership was found to moderate the relationship between reactive aggression and delinquency, and proactive aggression and delinquency, with stronger moderator effects for the latter. Those who were aggressive proactively and who had friends in a gang appear to be impacted most negatively with respect to delinquency. Parent criminality did not moderate these relationships. These findings highlight the need to effectively address the issues of child and adolescent aggression. Also, developing positive peer relations early is crucial for delinquency prevention. © The Author(s) 2016.

Toe of Ganges Chasma Landslide ( 8.0 S, 44.4W)

NASA Technical Reports Server (NTRS)

2001-01-01

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows shear striations, dark dunes banked up against the toe of the slide and over-riding light-toned ripples and boulders on surface of slide. These features can be used to determine quantitative aspects of surface processes.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

Designing a fixed-blade gang ripsaw arbor with a pencil

Treesearch

Charles J. Gatchell; Charles J. Gatchell

1996-01-01

This paper presents a step-by-step procedure for designing the "best" sequence of saw spacings for a fixed-blade gang ripsaw arbor. Using the information contained in a cutting bill and knowledge of the lumber width distributions to be processed, thousands of possible saw spacing sequences can be reduced to a few good ones.

Detecting Long-term Trend of Water Quality Indices of Dong-gang River, Taiwan Using Quantile Regression

NASA Astrophysics Data System (ADS)

Yang, D.; Shiau, J.

2013-12-01

ABSTRACT BODY: Abstract Surface water quality is an essential issue in water-supply for human uses and sustaining healthy ecosystem of rivers. However, water quality of rivers is easily influenced by anthropogenic activities such as urban development and wastewater disposal. Long-term monitoring of water quality can assess whether water quality of rivers deteriorates or not. Taiwan is a population-dense area and heavily depends on surface water for domestic, industrial, and agricultural uses. Dong-gang River is one of major resources in southern Taiwan for agricultural requirements. The water-quality data of four monitoring stations of the Dong-gang River for the period of 2000-2012 are selected for trend analysis. The parameters used to characterize water quality of rivers include biochemical oxygen demand (BOD), dissolved oxygen (DO), suspended solids (SS), and ammonia nitrogen (NH3-N). These four water-quality parameters are integrated into an index called river pollution index (RPI) to indicate the pollution level of rivers. Although widely used non-parametric Mann-Kendall test and linear regression exhibit computational efficiency to identify trends of water-quality indices, limitations of such approaches include sensitive to outliers and estimations of conditional mean only. Quantile regression, capable of identifying changes over time of any percentile values, is employed in this study to detect long-term trend of water-quality indices for the Dong-gang River located in southern Taiwan. The results show that Dong-gang River 4 stations from 2000 to 2012 monthly long-term trends in water quality.To analyze s Dong-gang River long-term water quality trends and pollution characteristics. The results showed that the bridge measuring ammonia Long-dong, BOD5 measure in that station on a downward trend, DO, and SS is on the rise, River Pollution Index (RPI) on a downward trend. The results form Chau-Jhou station also ahowed simialar trends .more and more near the

Assessing School-Based Gang Prevention Efforts in Urban Centers: Are These Programs Reaching Those Students Who May Benefit the Most?

ERIC Educational Resources Information Center

Rodriguez, Hector

2009-01-01

In recent years, schools have become a focal point for general delinquency and gang prevention programs for a variety of reasons. One premise behind this approach is that schools can serve as ideal settings for providing delinquency and intervention services because youths spend so much time there. School-based gang prevention efforts are supposed…

Small Town Insurgency: The Struggle for Information Dominance to Reduce Gang Violence

DTIC Science & Technology

2010-12-01

focuses on the importance of information dominance , there has been little research into component factors that might either promote, or inhibit, the... information dominance with respect to a counter-gang strategy. Through comparative analysis, our research suggests that improving relationships between

Associations Between Long-Term Gang Membership and Informal Social Control Processes, Drug Use, and Delinquent Behavior Among Mexican American Youth

PubMed Central

Cepeda, Alice; Saint Onge, Jarron M.; Nowotny, Kathryn M.; Valdez, Avelardo

2018-01-01

Research has found that among juveniles weak ties to informal social control entities such as parents, school, and conventional peers increase the probability of the initiation and continuation of deviant behaviors such as drug use and crime. Given the weak ties of formal social control mechanisms in highly disadvantaged communities, informal social control mechanisms are often an important deterrent that reduce or moderate engagement in deviant behaviors among serious and persistent offenders. This analysis examines the association between long-term gang membership and adolescent informal social control processes, drug use, and delinquency. This research is based on data from a study of 160 Mexican American male gang members between the ages of 16 and 20. Findings suggest that among gang members in this context, commonly studied informal control mechanisms such as the family and schools do not function to deter long-term gang membership that is associated with serious criminal and violent behavior and drug use. The implications for future research on desistance or continuation of antisocial behavior across the life course are discussed. PMID:25979430

Air Pollution Over the Ganges Basin and Northwest Bay of Bengal in the Early Postmonsoon Season Based on NASA MERRAero Data

NASA Technical Reports Server (NTRS)

Kishcha, Pavel; Da Silva, Arlindo M.; Starobinets, Boris; Alpert, Pinhas

2014-01-01

The MERRA Aerosol Reanalysis (MERRAero) has been recently developed at NASA's Global Modeling Assimilation Office. This reanalysis is based on a version of the Goddard Earth Observing System-5 (GEOS-5) model radiatively coupled with Goddard Chemistry, Aerosol, Radiation, and Transport aerosols, and it includes assimilation of bias-corrected aerosol optical thickness (AOT) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on both Terra and Aqua satellites. In October over the period 2002-2009, MERRAero showed that AOT was lower over the east of the Ganges basin than over the northwest of the Ganges basin: this was despite the fact that the east of the Ganges basin should have produced higher anthropogenic aerosol emissions because of higher population density, increased industrial output, and transportation. This is evidence that higher aerosol emissions do not always correspond to higher AOT over the areas where the effects of meteorological factors on AOT dominate those of aerosol emissions. MODIS AOT assimilation was essential for correcting modeled AOT mainly over the northwest of the Ganges basin, where AOT increments were maximal. Over the east of the Ganges basin and northwest Bay of Bengal (BoB), AOT increments were low and MODIS AOT assimilation did not contribute significantly to modeled AOT. Our analysis showed that increasing AOT trends over northwest BoB (exceeding those over the east of the Ganges basin) were reproduced by GEOS-5, not because of MODIS AOT assimilation butmainly because of the model capability of reproducing meteorological factors contributing to AOT trends. Moreover, vertically integrated aerosol mass flux was sensitive to wind convergence causing aerosol accumulation over northwest BoB.

City Life and Delinquency-Victimization, Fear of Crime and Gang Membership.

ERIC Educational Resources Information Center

Savitz, Leonard D.; And Others

Over 500 black and 500 white boys born in 1957 and attending Philadelphia schools were interviewed along with their mothers. The data were analyzed to discover how educational aspirations, social values, quality of life, fear of crime, victimization, family structure, father-son interaction, social attachments, and gang affiliation affected the…

Peace in the Streets: Breaking the Cycle of Gang Violence.

ERIC Educational Resources Information Center

Hernandez, Arturo

This book describes the experiences of an inexperienced young teacher who, with the support of parents and teenagers in a Los Angeles (California) neighborhood, created a one-room schoolhouse and began to teach 30 gang members, ranging in age from 13 to nearly 20. He had no teaching credentials or college degree and the school had a tiny budget,…

Does gang ripping hold the potential for higher clear cutting yields

Treesearch

Hiram Hallock; Pamela Giese

1980-01-01

Cutting yields from gang ripping hardwood lumber graded by the National Hardwood Lumber Association standard grades are determined using the technique of mathematical modeling. The lumber used is the same as that in an earlier mathematically modeled determination of cutting yields from traditional rough mill procedures. Mechanical cutting factors such as kerf, cutting...

The Evolution of Juventae Chasma, Valles Marineris, Mars: Progressive Collapse and Sedimentation

NASA Astrophysics Data System (ADS)

Fueten, F.; Novakovic, N.; Stesky, R.; Flahaut, J.; Hauber, E.; Rossi, A. P.

2017-11-01

Juventae Chasma is an isolated chasm located north of the interconnected chasms within Valles Marineris. It contains four separate interior layered deposit (ILD) mounds. We have combined layer measurements, as well as mineralogical data of the mounds with topographic data of the remaining chasm and the surrounding plateau. Our observations indicate that the chasm underwent a complex geological history. We suggest that individual ILD mounds are not contemporaneous with each other and a series of progressive collapses enlarged an initially smaller chasm to its current shape. ILDs were deposited in a lacustrine setting, and the time of ILD deposition was limited. Basin collapse and chasm enlargement continued beyond the time of ILD deposition and thus were not driven by sediment load. Glacial processes appear to have played a role in the late, postlacustrine history of the chasm. We present a simplified model that highlights some of the complexity of the chasm evolution, but acknowledge that the true history is undoubtedly more complicated.

Diverse Deposits in Melas Chasma

NASA Image and Video Library

2015-07-29

This scene captured by NASA Mars Reconnaissance Orbiter includes chaotic deposits with a wide range of colors. The deposits are distinctive with both unique colors and small-scale textures such as fracture patterns. These are probably sedimentary rocks, transported and deposited in water or air. The original layers may have been jumbled in a landslide. Dark or reddish sand dunes cover some of the bedrock. http://photojournal.jpl.nasa.gov/catalog/PIA19860

“It’s like we’re just renting over here”: The Pervasive Experiences of Discrimination of Filipino Immigrant Youth Gang Members in Hawai’i

PubMed Central

Kim, Su Yeong; Benner, Aprile D.; Takushi, Rena Mae Nalani; Ongbongan, Kathleen; Dennerlein, Donna; Spencer, Deborah K.

2009-01-01

Researchers, service providers, and policymakers must uncover and better understand the issues facing youths in Asian gangs in order to most effectively intervene with appropriate policies and programs. The present investigation sampled young male Filipino gang members in Hawai’i. Thematic analyses of the focus group data challenge the commonly held view of racial harmony in Hawai’i. It appears that racial and social discrimination from peers and authority figures propel Filipino boys to seek out gang membership as a way to protect themselves from being targets of oppression. PMID:19946383

Disturbance of the inclined inserting-type sand fence to wind-sand flow fields and its sand control characteristics

NASA Astrophysics Data System (ADS)

Cheng, Jian-jun; Lei, Jia-qiang; Li, Sheng-yu; Wang, Hai-feng

2016-06-01

The inclined inserting-type sand fence is a novel sand retaining wall adopted along the Lanxin High-Speed Railway II in Xinjiang for controlling and blocking sand movement. To verify the effectiveness of the new fence structure for sand prevention, a wind tunnel test was used for flow field test simulation of the sand fence. The results indicate that the inclined inserting-type sand fence was able to deflect the flow of the sand and was able to easily form an upward slant acceleration zone on the leeward side of the sand fence. As shown by the percentage change in sand collection rates on the windward side and the leeward side of the sand fence, the sand flux per unit area at 4 m height in the slant upward direction increased on the leeward side of the inclined inserting-type sand fence. By comparing the flow fields, this site is an acceleration zone, which also reaffirms the correspondence of wind-sand flow fields with the spatial distribution characteristic of the wind-carried sand motion. The field sand collection data indicates that under the effects of the inclined inserting-type sand fence, the sandy air currents passing in front and behind the sand fence not only changed in quality, but the grain composition and particle size also significantly changed, suggesting that the inclined inserting-type sand fence has a sorting and filtering effect on the sandy air currents that passed through. The fence retained coarse particulates on the windward side and fine particulates within the shade of the wind on the leeward side.

An Adapted Brief Strategic Family Therapy for Gang-Affiliated Mexican American Adolescents

ERIC Educational Resources Information Center

Valdez, Avelardo; Cepeda, Alice; Parrish, Danielle; Horowitz, Rosalind; Kaplan, Charles

2013-01-01

Objective: This study assessed the effectiveness of an adapted Brief Strategic Family Therapy (BSFT) intervention for gang-affiliated Mexican American adolescents and their parents. Methods: A total of 200 adolescents and their family caregivers were randomized to either a treatment or a control condition. Outcomes included adolescent substance…

Impact of a Comprehensive Whole Child Intervention and Prevention Program among Youths at Risk of Gang Involvement and Other Forms of Delinquency

ERIC Educational Resources Information Center

Koffman, Stephen; Ray, Alice; Berg, Sarah; Covington, Larry; Albarran, Nadine M.; Vasquez, Max

2009-01-01

Youths in gang-ridden neighborhoods are at risk for trauma-related mental health disorders, which are early indicators of likely school failure and delinquency. Such youths rarely seek out services for these problems. The Juvenile Intervention and Prevention Program (JIPP), a school-based gang intervention and prevention program in Los Angeles,…

School Dress Codes v. The First Amendment: Ganging up on Student Attire.

ERIC Educational Resources Information Center

Jahn, Karon L.

Do school dress codes written with the specific purpose of limiting individual dress preferences, including dress associated with gangs, infringe on speech freedoms granted by the First Amendment of the U.S. Constitution? Although the Supreme Court has extended its protection of political speech to nonverbal acts of communication, it has…

Findings from the Evaluation of OJJDP's Gang Reduction Program. Juvenile Justice Bulletin

ERIC Educational Resources Information Center

Cahill, Meagan; Hayeslip, David

2010-01-01

This bulletin draws on findings from an independent evaluation, conducted by the Urban Institute, of the Gang Reduction Program's (GRP) Impact in Los Angeles, California; Milwaukee, Wisconsin; North Miami Beach, Florida; and Richmond, Virginia, to examine how effectively these sites implemented the program. Following are some of the authors' key…

The Challenges of Gangs and Youth Violence in the Schools. Fourth CCBD Mini-Library Series: Addressing the Diverse Needs of Children and Youth with Emotional/Behavioral Disorders--Programs That Work.

ERIC Educational Resources Information Center

Grant, Sharon H.; Van Acker, Richard

Review of the current knowledge concerning youth violence and gang behavior considers risk factors for violence and gang formation, functions served by violence and gang membership, and strategies that have been empirically validated to be either beneficial or ineffective. Following an introductory chapter, the first chapter looks at the nature of…

Bioaccumulation profiles of polychlorinated biphenyl congeners and organochlorine pesticides in Ganges River dolphins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Senthilkumar, K.; Kannan, K.; Sinha, R.K.

1999-07-01

Isomer-specific concentrations of polychlorinated biphenyls (PCBs) including non-, mono-, and di-ortho-substituted congeners, DDT and its metabolites, hexachlorocyclohexane (HCH) isomers, chlordane compounds, and hexachlorobenzene (HCB) were determined in river dolphin blubber and prey fishes collected during 1993 through 1996 from the River Ganges in India. Concentrations of organochlorines were also measured in the milk and liver of dolphins, benthic invertebrates, and sediments. The DDTs and PCBs were the predominant compounds found in dolphin tissues and fish that comprise the diet of dolphins. Concentrations of DDTs and PCBs in the blubber of dolphins were in the range of 30 to 120 andmore » 1.5 to 25 {micro}g/g, lipid weight, respectively. Penta- and hexachlorobiphenyls collectively accounted for 68 to 80% of the total PCB concentrations in river dolphins. Hexachlorobiphenyl congener 138 (2.2{prime}, 3,4,4{prime},5{prime}-) was the most abundant in dolphin blubber and prey fishes. The isomer/congener pattern of PCBs and organchlorine pesticides suggested that there is less metabolism due to cytochrome P450 enzymes in Ganges river dolphins than in marine or terrestrial mammals. The mean 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs) estimated in river dolphin blubber was greater than those that can cause adverse effects in mink. Comparison of organochlorine concentrations in river dolphins with those of the values reported for samples analyzed during 1988 through 1992 suggested that the contamination by these compounds has increased in the River Ganges.« less

Coupled changes in sand grain size and sand transport driven by changes in the upstream supply of sand in the Colorado River: relative importance of changes in bed-sand grain size and bed-sand area

USGS Publications Warehouse

Topping, D.J.; Rubin, D.M.; Melis, T.S.

2007-01-01

Sand transport in the Colorado River in Marble and Grand canyons was naturally limited by the upstream supply of sand. Prior to the 1963 closure of Glen Canyon Dam, the river exhibited the following four effects of sand supply limitation: (1) hysteresis in sediment concentration, (2) hysteresis in sediment grain size coupled to the hysteresis in sediment concentration, (3) production of inversely graded flood deposits, and (4) development or modification of a lag between the time of a flood peak and the time of either maximum or minimum (depending on reach geometry) bed elevation. Construction and operation of the dam has enhanced the degree to which the first two of these four effects are evident, and has not affected the degree to which the last two effects of sand supply limitation are evident in the Colorado River in Marble and Grand canyons. The first three of the effects involve coupled changes in suspended-sand concentration and grain size that are controlled by changes in the upstream supply of sand. During tributary floods, sand on the bed of the Colorado River fines; this causes the suspended sand to fine and the suspended-sand concentration to increase, even when the discharge of water remains constant. Subsequently, the bed is winnowed of finer sand, the suspended sand coarsens, and the suspended-sand concentration decreases independently of discharge. Also associated with these changes in sand supply are changes in the fraction of the bed that is covered by sand. Thus, suspended-sand concentration in the Colorado River is likely regulated by both changes in the bed-sand grain size and changes in the bed-sand area. A physically based flow and suspended-sediment transport model is developed, tested, and applied to data from the Colorado River to evaluate the relative importance of changes in the bed-sand grain size and changes in the bed-sand area in regulating suspended-sand concentration. Although the model was developed using approximations for steady

Numerical slope stability simulations of chasma walls in Valles Marineris/Mars using a distinct element method (dem).

NASA Astrophysics Data System (ADS)

Imre, B.

2003-04-01

NUMERICAL SLOPE STABILITY SIMULATIONS OF CHASMA WALLS IN VALLES MARINERIS/MARS USING A DISTINCT ELEMENT METHOD (DEM). B. Imre (1) (1) German Aerospace Center, Berlin Adlershof, bernd.imre@gmx.net The 8- to 10-km depths of Valles Marineris (VM) offer excellent views into the upper Martian crust. Layering, fracturing, lithology, stratigraphy and the content of volatiles have influenced the evolution of the Valles Marineris wallslopes. But these parameters also reflect the development of VM and its wall slopes. The scope of this work is to gain understanding in these parameters by back-simulating the development of wall slopes. For that purpose, the two dimensional Particle Flow Code PFC2D has been chosen (ITASCA, version 2.00-103). PFC2D is a distinct element code for numerical modelling of movements and interactions of assemblies of arbitrarily sized circular particles. Particles may be bonded together to represent a solid material. Movements of particles are unlimited. That is of importance because results of open systems with numerous unknown variables are non-unique and therefore highly path dependent. This DEM allows the simulation of whole development paths of VM walls what makes confirmation of the model more complete (e.g. Oreskes et al., Science 263, 1994). To reduce the number of unknown variables a proper (that means as simple as possible) field-site had to be selected. The northern wall of eastern Candor Chasma has been chosen. This wall is up to 8-km high and represents a significant outcrop of the upper Martian crust. It is quite uncomplex, well-aligned and of simple morphology. Currently the work on the model is at the stage of performing the parameter study. Results will be presented via poster by the EGS-Meeting.

Occurrence of Organic Contaminants in Lower Reaches of River Ganges, India

NASA Astrophysics Data System (ADS)

Dutta Gupta, S.; Bhattacharya, A.; Mukherjee, A.; Bhattacharya, J.

2016-12-01

The Gangetic plain of eastern India has been long known as the "bread basket" of the Indian subcontinent. However, indiscriminate use of pesticides in the agricultural fields is to increase crop production. These resulted to increased vulnerability of pesticide pollution of the hydrological systems of the area, potentially exposing to significant human health consequences. Our present study delineate pesticides occurrence in lower Ganges in West Bengal. The major organic contaminants regularly detected in the studied reaches of the Ganges belong to wide range of herbicides and insecticides, which especially include organochlorides and organophosphates such as Aldrin, Alachlor, Lindane, Malathion, Chlorpyrifos and Methyl parathion. Results show Alachlor and Malathion were the most abundant organic contaminant in the river. Among the other pesticides, one of the most venomous substances, Malathion has been noticed from the last year insecticide screening study. The mean concentration of river water Malathion was found to be 5 times higher than the maximum concentration limit (MCL). Presence of Malathion or its derivative Malaoxon in river water is suspected to be caused by agricultural run-off and it showed a good correlation with river water chlorine concentrations.

The Likelihood of Collaboration Between Central American Transnational Gangs and Terrorist Organizations

DTIC Science & Technology

2007-03-01

As Rolando Gamez, a resident of Escuintla – a town 28 miles southwest of the capital, Guatemala City – maintains, "This is a war and the gang...Director of Investigations in El Salvador, Douglas Omar Garcia Fumes, agrees, "They continue to operate even after they’re arrested. Orders to kill are

Assessment of Environmental Flows for the Rivers of Western Ganges Delta with Special Reference to Indian Sundarban

NASA Astrophysics Data System (ADS)

Bhadra, T.; Hazra, S.; Ghosh, S.; Barman, B. C.

2016-12-01

The Indian Sundarban, situated on the western tide-dominated part of the Ganges delta was formed by the sedimentation of the Ganges and its tributaries. Freshwater is a scarce resource in the Sundarban though it is traversed by rivers. Most of the rivers of Western Ganges Delta, which used to nourish the Sundarban, have become defunct with the passage of time. To ensure sustainable flow and to enhance the flow-dependent ecosystem services in this region, assessment of environmental flows within the system is required. A pilot assessment of environment flows, supported by IUCN has been carried out in some specific river reaches of Western Ganges Delta under the present study. The holistic Building Block Methodology (BBM) has been modified and used for the assessment of environmental flows. In the modified BBM, three distinctive blocks namely Hydro-Morphology, Ecology and Socio-Economy have been selected and indicators like Ganges Dolphin (Platanista gangetica), Sundari tree (Heritiera fomes) and Hilsa fish (Tenualosa ilisha) etc. have been determined to assess the environmental flows. As the discharge data of the selected rivers are restricted in the public domain, the SWAT model has been run to generate the discharge data of the classified rivers. The Hydraulic model, HEC-RAS has been calibrated in the selected River reaches to assess the habitat availability and its changes for indicator species under different flow condition. The study reveals that River Bhagirathi-Hugli requires 150-427 cumec additional water in monsoon and 850-1127 cumec additional water in post-monsoon months for Hilsa migration, whereas 327-486 cumec additional water in pre-monsoon and dry season and 227-386 cumec additional water in post-monsoon months are required for Dolphin movement. Flow requirement of river Ichhamati has also been estimated under the present study. The total required flow for the Sundarban ecosystem to reduce the salinity level from 30ppt to 14ppt during the dry and pre

Natural Selection in a Bangladeshi Population from the Cholera-Endemic Ganges River Delta

PubMed Central

Karlsson, Elinor K.; Harris, Jason B.; Tabrizi, Shervin; Rahman, Atiqur; Shlyakhter, Ilya; Patterson, Nick; O'Dushlaine, Colm; Schaffner, Stephen F.; Gupta, Sameer; Chowdhury, Fahima; Sheikh, Alaullah; Shin, Ok Sarah; Ellis, Crystal; Becker, Christine E.; Stuart, Lynda M.; Calderwood, Stephen B.; Ryan, Edward T.; Qadri, Firdausi; Sabeti, Pardis C.; LaRocque, Regina C.

2015-01-01

As an ancient disease with high fatality, cholera has likely exerted strong selective pressure on affected human populations. We performed a genome-wide study of natural selection in a population from the Ganges River Delta, the historic geographic epicenter of cholera. We identified 305 candidate selected regions using the Composite of Multiple Signals (CMS) method. The regions were enriched for potassium channel genes involved in cyclic AMP-mediated chloride secretion and for components of the innate immune system involved in NF-κB signaling. We demonstrate that a number of these strongly selected genes are associated with cholera susceptibility in two separate cohorts. We further identify repeated examples of selection and association in an NF-kB / inflammasome-dependent pathway that is activated in vitro by Vibrio cholerae. Our findings shed light on the genetic basis of cholera resistance in a population from the Ganges River Delta and present a promising approach for identifying genetic factors influencing susceptibility to infectious diseases. PMID:23825302

Evaluation of Durability Parameters of Concrete with Manufacture Sand and River Sand

NASA Astrophysics Data System (ADS)

Sangoju, Bhaskar; Ramesh, G.; Bharatkumar, B. H.; Ramanjaneyulu, K.

2017-09-01

Most of the states in our country have banned sand quarrying from the river beds, causing a scarcity of natural river sand for the construction sector. Manufacture sand (M-sand) is one of the alternate solutions to replace the river sand (R-sand) in concrete. The main aim of the present study is to evaluate the durability parameters of concrete with M-sand when compared to that of concrete with R-sand. Corrosion of reinforcement is one of the main deteriorating mechanisms of reinforced concrete due to the ingress of chloride ions or carbon-di-oxide. For comparative evaluation of durability parameters, accelerated tests such as Rapid Chloride Permeability Test, Rapid Chloride Migration Test and accelerated carbonation test were carried out on specimens of R-sand and M-sand. All tests were carried out after 90 days of casting. Test results reveal that the durability parameters of the concrete with M-sand in chloride induced environment is relatively better than that of concrete with R-sand and hence is recommended to use M-sand as a replacement to R-sand.

Sand transportation and reverse patterns over leeward face of sand dune

NASA Astrophysics Data System (ADS)

Jiang, Hong; Dun, Hongchao; Tong, Ding; Huang, Ning

2017-04-01

Sand saltation has complex interactions with turbulent flow and dune form. Most models of wind-blown sand consider ideal circumstances such as steady wind velocity and a flat surface, and the bulk of data on wind flow and sand transport over an individual dune has focused mostly on the influence of dune shape or inter-dune space on the wind flow, neglecting the effect of morphology on sand saltation, particularly airflow and sand transportation over the leeward slope. Wind flow structures over the leeward slope of sand dunes have a fundamental influence on the organization of sand dunes. In order to understand sand dune dynamics, lee face airflow and sediment transportation should be paid more attention. Previous field observations could not measure turbulent flow structure well because of the limited observation points and the influence of experiment structure on wind field. In addition, the reverse sand particles over leeward face could not be collected by sand trap in field. Numerous field observations could not measure turbulent flow structure because of the limited observation points and the influence of experimental structures on the wind field. In addition, the reverse transport of sand particles over leeward face could not be collected by sand traps in field. Therefore, this paper aims to investigate the turbulent flow structure and sand transport pattern over the leeward slope. A numerical model of sand saltation over slope terrain is constructed, which also considers the coupling effects between air flow and sand particles. The large eddy simulation method is used to model turbulent flow. Sand transport is simulated by tracking the trajectory of each sand particle. The results show that terrain significantly alters the turbulent air flow structure and wind-blown sand movement, especially over the leeward slope. Here, mass flux increases initially and then decreases with height in the reversed flow region in the direction of wind flow, and the mass flux

Countering Gang Violence: What Small Town Communities Can Learn from the US Military

DTIC Science & Technology

2011-05-03

city is also home to two of the most notorious Hispanic gangs operating in the US. The Nuestra Familia and the Mexican Mafia have approximately 11...within Salinas until all communities are capable of self-policing. Critical to this mission will be Salinas‟ ability to actually „connect‟ with the

The effects of self-control, gang membership, and parental attachment/identification on police contacts among Latino and African American youths.

PubMed

Flexon, Jamie L; Greenleaf, Richard G; Lurigio, Arthur J

2012-04-01

This study assessed the correlates of self-control and police contact in a sample of Chicago public high school students. The investigation examined the effects of parental attachment/identification, family structure, and peer association on self-control and the effects of parental attachment/identification, family structure, peer association, and self-control on police contact. Differences between African American and Latino youth on the predictors of the two dependent measures were tested in separate regression models. Weak parental attachment/identification and gang affiliation (peer association) predicted low self-control among all students. Among African American youth, only weak maternal attachment/identification predicted low self-control; both weak maternal attachment/identification and gang affiliation predicted low self-control among Latino youth. Gang affiliation predicted police stops (delinquency) among African Americans but not among Latinos. However, both African American and Latino students with lower self-control were more likely to be stopped by the police than those with higher self-control.

Deportation of Gang Members: Sub-Optimal Solution for Both America and Mexico

DTIC Science & Technology

2011-10-28

Back the Streets 36 James C. Howell. “Gang prevention: An Overview of Research and Programs”, Office of Juvenile Justice and Delinquency ...55 U.S. Department of Justice, Office of Justice and Juvenile Delinquency Prevention, Boston Strategy To Prevent Youth Violence... Delinquency Prevention, U.S. Department of Justice, Juvenile Justice Bulletin, December 2010, https://www.ncjrs.gov/pdffiles1/ojjdp/231116.pdf

Advantages of Group Therapy for Adolescent Participants in the Same Gang Rape

ERIC Educational Resources Information Center

Etgar, Talia; Prager, Keren Ganot

2009-01-01

This paper deals with the issue of including in the same therapeutic group in a prison setting two (or more) young people who participated in the same gang rape. We provide a background for group therapy with adolescent sex offenders and point out the characteristics of group rape. In addition, we describe the uniqueness of working in a prison as…

Predicting sexual coercion in early adulthood: The transaction among maltreatment, gang affiliation, and adolescent socialization of coercive relationship norms.

PubMed

Ha, Thao; Kim, Hanjoe; Christopher, Caroline; Caruthers, Allison; Dishion, Thomas J

2016-08-01

This study tested a transactional hypothesis predicting early adult sexual coercion from family maltreatment, early adolescent gang affiliation, and socialization of adolescent friendships that support coercive relationship norms. The longitudinal study of a community sample of 998 11-year-olds was intensively assessed in early and middle adolescence and followed to 23-24 years of age. At age 16-17 youth were videotaped with a friend, and their interactions were coded for coercive relationship talk. Structural equation modeling revealed that maltreatment predicted gang affiliation during early adolescence. Both maltreatment and gang affiliation strongly predicted adolescent sexual promiscuity and coercive relationship norms with friends at age 16-17 years. Adolescent sexual promiscuity, however, did not predict sexual coercion in early adulthood. In contrast, higher levels of observed coercive relationship talk with a friend predicted sexual coercion in early adulthood for both males and females. These findings suggest that peers have a socialization function in the development of norms prognostic of sexual coercion, and the need to consider peers in the promotion of healthy relationships.

Clicking in shallow rivers: short-range echolocation of Irrawaddy and Ganges River dolphins in a shallow, acoustically complex habitat.

PubMed

Jensen, Frants H; Rocco, Alice; Mansur, Rubaiyat M; Smith, Brian D; Janik, Vincent M; Madsen, Peter T

2013-01-01

Toothed whales (Cetacea, odontoceti) use biosonar to navigate their environment and to find and catch prey. All studied toothed whale species have evolved highly directional, high-amplitude ultrasonic clicks suited for long-range echolocation of prey in open water. Little is known about the biosonar signals of toothed whale species inhabiting freshwater habitats such as endangered river dolphins. To address the evolutionary pressures shaping the echolocation signal parameters of non-marine toothed whales, we investigated the biosonar source parameters of Ganges river dolphins (Platanista gangetica gangetica) and Irrawaddy dolphins (Orcaella brevirostris) within the river systems of the Sundarban mangrove forest. Both Ganges and Irrawaddy dolphins produced echolocation clicks with a high repetition rate and low source level compared to marine species. Irrawaddy dolphins, inhabiting coastal and riverine habitats, produced a mean source level of 195 dB (max 203 dB) re 1 µPapp whereas Ganges river dolphins, living exclusively upriver, produced a mean source level of 184 dB (max 191) re 1 µPapp. These source levels are 1-2 orders of magnitude lower than those of similar sized marine delphinids and may reflect an adaptation to a shallow, acoustically complex freshwater habitat with high reverberation and acoustic clutter. The centroid frequency of Ganges river dolphin clicks are an octave lower than predicted from scaling, but with an estimated beamwidth comparable to that of porpoises. The unique bony maxillary crests found in the Platanista forehead may help achieve a higher directionality than expected using clicks nearly an octave lower than similar sized odontocetes.

Clicking in Shallow Rivers: Short-Range Echolocation of Irrawaddy and Ganges River Dolphins in a Shallow, Acoustically Complex Habitat

PubMed Central

Jensen, Frants H.; Rocco, Alice; Mansur, Rubaiyat M.; Smith, Brian D.; Janik, Vincent M.; Madsen, Peter T.

2013-01-01

Toothed whales (Cetacea, odontoceti) use biosonar to navigate their environment and to find and catch prey. All studied toothed whale species have evolved highly directional, high-amplitude ultrasonic clicks suited for long-range echolocation of prey in open water. Little is known about the biosonar signals of toothed whale species inhabiting freshwater habitats such as endangered river dolphins. To address the evolutionary pressures shaping the echolocation signal parameters of non-marine toothed whales, we investigated the biosonar source parameters of Ganges river dolphins (Platanista gangetica gangetica) and Irrawaddy dolphins (Orcaella brevirostris) within the river systems of the Sundarban mangrove forest. Both Ganges and Irrawaddy dolphins produced echolocation clicks with a high repetition rate and low source level compared to marine species. Irrawaddy dolphins, inhabiting coastal and riverine habitats, produced a mean source level of 195 dB (max 203 dB) re 1 µPapp whereas Ganges river dolphins, living exclusively upriver, produced a mean source level of 184 dB (max 191) re 1 µPapp. These source levels are 1–2 orders of magnitude lower than those of similar sized marine delphinids and may reflect an adaptation to a shallow, acoustically complex freshwater habitat with high reverberation and acoustic clutter. The centroid frequency of Ganges river dolphin clicks are an octave lower than predicted from scaling, but with an estimated beamwidth comparable to that of porpoises. The unique bony maxillary crests found in the Platanista forehead may help achieve a higher directionality than expected using clicks nearly an octave lower than similar sized odontocetes. PMID:23573197

Water resources management in the Ganges Basin: a comparison of three strategies for conjunctive use of groundwater and surface water

USGS Publications Warehouse

Khan, Mahfuzur R.; Voss, Clifford I.; Yu, Winston; Michael, Holly A.

2014-01-01

The most difficult water resources management challenge in the Ganges Basin is the imbalance between water demand and seasonal availability. More than 80 % of the annual flow in the Ganges River occurs during the 4-month monsoon, resulting in widespread flooding. During the rest of the year, irrigation, navigation, and ecosystems suffer because of water scarcity. Storage of monsoonal flow for utilization during the dry season is one approach to mitigating these problems. Three conjunctive use management strategies involving subsurface water storage are evaluated in this study: Ganges Water Machine (GWM), Pumping Along Canals (PAC), and Distributed Pumping and Recharge (DPR). Numerical models are used to determine the efficacy of these strategies. Results for the Indian State of Uttar Pradesh (UP) indicate that these strategies create seasonal subsurface storage from 6 to 37 % of the yearly average monsoonal flow in the Ganges exiting UP over the considered range of conditions. This has clear implications for flood reduction, and each strategy has the potential to provide irrigation water and to reduce soil waterlogging. However, GWM and PAC require significant public investment in infrastructure and management, as well as major shifts in existing water use practices; these also involve spatially-concentrated pumping, which may induce land subsidence. DPR also requires investment and management, but the distributed pumping is less costly and can be more easily implemented via adaptation of existing water use practices in the basin.

Basin in the West Candor Chasma Layered Deposits

NASA Image and Video Library

2013-08-21

This basin in Ceti Mensa, as seen by by NASA Mars Reconnaissance Orbiter, exposes concentric rings in the sedimentary layers. Dark sand ripples and textures in the bedrock suggesting wind scouring are also apparent.

Implications of agricultural land use change to ecosystem services in the Ganges delta.

PubMed

Islam, G M Tarekul; Islam, A K M Saiful; Shopan, Ahsan Azhar; Rahman, Md Munsur; Lázár, Attila N; Mukhopadhyay, Anirban

2015-09-15

Ecosystems provide the basis for human civilization and natural capital for green economy and sustainable development. Ecosystem services may range from crops, fish, freshwater to those that are harder to see such as erosion regulation, carbon sequestration, and pest control. Land use changes have been identified as the main sources of coastal and marine pollution in Bangladesh. This paper explores the temporal variation of agricultural land use change and its implications with ecosystem services in the Ganges delta. With time agricultural lands have been decreased and wetlands have been increased at a very high rate mainly due to the growing popularity of saltwater shrimp farming. In a span of 28 years, the agricultural lands have been reduced by approximately 50%, while the wetlands have been increased by over 500%. A large portion (nearly 40%) of the study area is covered by the Sundarbans which remained almost constant which can be attributed to the strict regulatory intervention to preserve the Sundarbans. The settlement & others land use type has also been increased to nearly 5%. There is a gradual uptrend of shrimp and fish production in the study area. The findings suggest that there are significant linkages between agricultural land use change and ecosystem services in the Ganges delta in Bangladesh. The continuous decline of agricultural land (due to salinization) and an increase of wetland have been attributed to the conversion of agricultural land into shrimp farming in the study area. Such land use change requires significant capital, therefore, only investors and wealthier land owners can get the higher profit from the land conversion while the poor people is left with the environmental consequences that affect their long-term lives and livelihood. An environmental management plan is proposed for sustainable land use in the Ganges delta in Bangladesh. Copyright © 2014 Elsevier Ltd. All rights reserved.

Principals' Leadership Behaviors in Gang-Impacted High Schools and Their Effects on Pupil Climate.

ERIC Educational Resources Information Center

Schwartz, Audrey J.

Although viable leadership models for schools with differing social contexts are in great demand, empirical studies of high school principals have not produced consistent results. This paper summarizes part of a larger project designed to identify leadership behaviors of principals in "gang-impacted" and other secondary schools. The…

Benchmarking wide swath altimetry-based river discharge estimation algorithms for the Ganges river system

NASA Astrophysics Data System (ADS)

Bonnema, Matthew G.; Sikder, Safat; Hossain, Faisal; Durand, Michael; Gleason, Colin J.; Bjerklie, David M.

2016-04-01

The objective of this study is to compare the effectiveness of three algorithms that estimate discharge from remotely sensed observables (river width, water surface height, and water surface slope) in anticipation of the forthcoming NASA/CNES Surface Water and Ocean Topography (SWOT) mission. SWOT promises to provide these measurements simultaneously, and the river discharge algorithms included here are designed to work with these data. Two algorithms were built around Manning's equation, the Metropolis Manning (MetroMan) method, and the Mean Flow and Geomorphology (MFG) method, and one approach uses hydraulic geometry to estimate discharge, the at-many-stations hydraulic geometry (AMHG) method. A well-calibrated and ground-truthed hydrodynamic model of the Ganges river system (HEC-RAS) was used as reference for three rivers from the Ganges River Delta: the main stem of Ganges, the Arial-Khan, and the Mohananda Rivers. The high seasonal variability of these rivers due to the Monsoon presented a unique opportunity to thoroughly assess the discharge algorithms in light of typical monsoon regime rivers. It was found that the MFG method provides the most accurate discharge estimations in most cases, with an average relative root-mean-squared error (RRMSE) across all three reaches of 35.5%. It is followed closely by the Metropolis Manning algorithm, with an average RRMSE of 51.5%. However, the MFG method's reliance on knowledge of prior river discharge limits its application on ungauged rivers. In terms of input data requirement at ungauged regions with no prior records, the Metropolis Manning algorithm provides a more practical alternative over a region that is lacking in historical observations as the algorithm requires less ancillary data. The AMHG algorithm, while requiring the least prior river data, provided the least accurate discharge measurements with an average wet and dry season RRMSE of 79.8% and 119.1%, respectively, across all rivers studied. This poor

Drugs, Gangs, Transnational Organized Crime and Malgoverened Spaces in the Americas

DTIC Science & Technology

2015-01-01

3 Drugs, Gangs, Transnational Organized Crime and “Malgoverened Spaces” in the Americas R. Evan Ellis1 During the spring of 2014, the U.S. media...and Washington politics were briefly dominated by the crisis of thousands of children from Central America detained at the Mexican border as they... Americas have received increasing attention as threats to both the U.S. and the region.3 Many good analy- ses have been done of the phenomenon of

Differential heating in the Indian Ocean differentially modulates precipitation in the Ganges and Brahmaputra basins

USGS Publications Warehouse

Pervez, Md Shahriar; Henebry, Geoffrey M.

2016-01-01

Indo-Pacific sea surface temperature dynamics play a prominent role in Asian summer monsoon variability. Two interactive climate modes of the Indo-Pacific—the El Niño/Southern Oscillation (ENSO) and the Indian Ocean dipole mode—modulate the amount of precipitation over India, in addition to precipitation over Africa, Indonesia, and Australia. However, this modulation is not spatially uniform. The precipitation in southern India is strongly forced by the Indian Ocean dipole mode and ENSO. In contrast, across northern India, encompassing the Ganges and Brahmaputra basins, the climate mode influence on precipitation is much less. Understanding the forcing of precipitation in these river basins is vital for food security and ecosystem services for over half a billion people. Using 28 years of remote sensing observations, we demonstrate that (i) the tropical west-east differential heating in the Indian Ocean influences the Ganges precipitation and (ii) the north-south differential heating in the Indian Ocean influences the Brahmaputra precipitation. The El Niño phase induces warming in the warm pool of the Indian Ocean and exerts more influence on Ganges precipitation than Brahmaputra precipitation. The analyses indicate that both the magnitude and position of the sea surface temperature anomalies in the Indian Ocean are important drivers for precipitation dynamics that can be effectively summarized using two new indices, one tuned for each basin. These new indices have the potential to aid forecasting of drought and flooding, to contextualize land cover and land use change, and to assess the regional impacts of climate change.

Coffeyville, Kansas: The Town That Stopped the Dalton Gang. Teaching with Historic Places.

ERIC Educational Resources Information Center

Hunter, Kathleen

By 1890 the legendary outlaws of the 1870s and 1880s were mostly dead or in prison. When Luther Perkins erected his new bank building in Coffeyville, Kansas, a bank robbery was the farthest thing from his mind. But the Dalton cousins, former Coffeyville residents, were interested in the bank because they wanted to outdo the James gang by using the…

Industrial sand and gravel

USGS Publications Warehouse

Dolley, T.P.

2011-01-01

Domestic production of industrial sand and gravel in 2010 was about 26.5 Mt (29.2 million st), a 6-percent increased from 2009. Certain end uses of industrial sand and gravel, such as sand for container glass, golf course sand, recreational sand, specialty glass and water filtration, showed increased demand in 2010.

Assessing regional climate simulations of the last 30 years (1982-2012) over Ganges-Brahmaputra-Meghna River Basin

NASA Astrophysics Data System (ADS)

Khandu; Awange, Joseph L.; Anyah, Richard; Kuhn, Michael; Fukuda, Yoichi

2017-10-01

The Ganges-Brahmaputra-Meghna (GBM) River Basin presents a spatially diverse hydrological regime due to it's complex topography and escalating demand for freshwater resources. This presents a big challenge in applying the current state-of-the-art regional climate models (RCMs) for climate change impact studies in the GBM River Basin. In this study, several RCM simulations generated by RegCM4.4 and PRECIS are assessed for their seasonal and interannual variations, onset/withdrawal of the Indian monsoon, and long-term trends in precipitation and temperature from 1982 to 2012. The results indicate that in general, RegCM4.4 and PRECIS simulations appear to reasonably reproduce the mean seasonal distribution of precipitation and temperature across the GBM River Basin, although the two RCMs are integrated over a different domain size. On average, the RegCM4.4 simulations overestimate monsoon precipitation by {˜ }26 and {˜ }5% in the Ganges and Brahmaputra-Meghna River Basin, respectively, while PRECIS simulations underestimate (overestimate) the same by {˜ }7% ({˜ }16%). Both RegCM4.4 and PRECIS simulations indicate an intense cold bias (up to 10° C) in the Himalayas, and are generally stronger in the RegCM4.4 simulations. Additionally, they tend to produce high precipitation between April and May in the Ganges (RegCM4.4 simulations) and Brahmaputra-Meghna (PRECIS simulations) River Basins, resulting in early onset of the Indian monsoon in the Ganges River Basin. PRECIS simulations exhibit a delayed monsoon withdrawal in the Brahmaputra-Meghna River Basin. Despite large spatial variations in onset and withdrawal periods across the GBM River Basin, the basin-averaged results agree reasonably well with the observed periods. Although global climate model (GCM) driven simulations are generally poor in representing the interannual variability of precipitation and winter temperature variations, they tend to agree well with observed precipitation anomalies when driven by

Soil Gas Sample Handling: Evaluation of Water Removal and Sample Ganging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fritz, Brad G.; Abrecht, David G.; Hayes, James C.

2016-10-31

Soil gas sampling is currently conducted in support of Nuclear Test Ban treaty verification. Soil gas samples are collected and analyzed for isotopes of interest. Some issues that can impact sampling and analysis of these samples are excess moisture and sample processing time. Here we discuss three potential improvements to the current sampling protocol; a desiccant for water removal, use of molecular sieve to remove CO 2 from the sample during collection, and a ganging manifold to allow composite analysis of multiple samples.

Human Services Students' Attitudes toward Working with an Inner-City Gang Member: The Case of Alphonse.

ERIC Educational Resources Information Center

Ancis, Julie R.; Burke, Mary C.

1997-01-01

Investigates the attitudes of 91 human service counseling students toward working with an inner-city gang member. Results reveal qualitative differences in students' self-perceived ability to work with this client. Presents implications for human service education and training. (MKA)

Evolution of the P/Shoemaker-Levy 9 Gang

NASA Image and Video Library

1998-05-02

This series of eight NASA Hubble Space Telescope "snapshots" shows the evolution of the P-Q complex, also called the "gang of four" region, of comet P/Shoemaker-Levy 9. The eight individual frames chronicle changes in the comet during the 12 months before colliding with Jupiter. The sequence shows that the relative separations of the various cometary fragments, thought to range in size from about 500 meters to almost 4 km (2.5 miles) across, changed dramatically over this period. The apparent separation of Q1 and Q2 was only about 1100 kilometers (680 miles) on 1 July 1993 and increased to 28,000 kilometers (17,400 miles) by 20 July 1994. http://photojournal.jpl.nasa.gov/catalog/PIA01264

Affiliation with Antisocial Crowds and Psychosocial Outcomes in a Gang-Impacted Urban Middle School

ERIC Educational Resources Information Center

Schwartz, David; Hopmeyer, Andrea; Luo, Tana; Ross, Alexandra C.; Fischer, Jesse

2017-01-01

This longitudinal study examined the psychosocial adjustment of adolescents who affiliate with antisocial crowds in a gang-impacted urban environment. We followed 405 adolescents (219 boys, 186 girls; average age of 11.51 years, SD = 0.61; 84% Latino, 9% Asian, and 7% other or unclassified) for one academic year. These youth attended a middle…

Submarine sand ridges and sand waves in the eastern part of the China Sea

NASA Astrophysics Data System (ADS)

Wu, Ziyin; Li, Shoujun; Shang, Jihong; Zhou, Jieqiong; Zhao, Dineng; Liang, Yuyang

2016-04-01

Integrated with multi-beam and single-beam echo sounding data, as well as historical bathymetric data, submarine bathymetric maps of the eastern part of the China Sea, including the Bohai Sea, Huanghai Sea, and East China Sea, are constructed to systematically study submarine sand ridges and sand waves in the eastern part of the China Sea, combined with high-resolution seismic, sub-bottom profile and borehole data. Submarine sand ridges are extraordinarily developed in the eastern part of the China Sea, and 7 sand ridge areas can be divided from north to south, that is, the Laotieshan Channel sand ridge area in the Bohai Sea, the Korea Bay sand ridge area in the southern Huanghai Sea, the sand ridge area in the eastern Huanghai islands and the Huanghai Troughs, the Jianggang sand ridge area in the western Huanghai Sea, the sand ridge area in the East China Sea shelf, and the sand ridge and sand wave area in the Taiwan Strait and Taiwan Banks. The distribution area of the sand ridges and sand waves covers more than 450,000 km2, wherein ~10,000 km2 in the Bohai Bay, ~200,000 km2 in the Huanghai Sea, ~200,000 km2 in the East China Sea shelf, and ~40,000 km2 in the Taiwan Strait and Taiwan Banks, respectively. The great mass of sand ridges are distributed within water depth of 5-160 m, with a total length of over 160 km and a main width of 5-10 km. The inner structure of the sand ridges presents features of high-angle inclined beddings, with main lithology of sands, sand-mud alternations partly visible, and a small number of mud cores. Dating results indicate that the sand ridges in the eastern part of the China Sea are mainly developed in the Holocene. Sea-level variation dominates the sand ridge evolution in the eastern part of the China Sea since the LGM, and the sand ridges developed in the area of < 60m water depth are appeared in bad activity, meanwhile sand ridges with good activity are still developed in large scale.

Fecal indicators in sand, sand contact, and risk of enteric illness among beachgoers

PubMed Central

Heaney, Christopher D.; Sams, Elizabeth; Dufour, Alfred P.; Brenner, Kristen P.; Haugland, Richard A.; Chern, Eunice; Wing, Steve; Marshall, Stephen; Love, David C.; Serre, Marc; Noble, Rachel; Wade, Timothy J.

2011-01-01

Background Beach sand can harbor fecal indicator organisms and pathogens, but enteric illness risk associated with sand contact remains unclear. Methods In 2007, visitors at two recreational marine beaches were asked on the day of their visit about sand contact. Ten to 12 days later, participants answered questions about health symptoms since the visit. F+ coliphage, Enterococcus, Bacteroidales, fecal Bacteroides, and Clostridium spp. in wet sand were measured using culture and molecular methods. Results We analyzed 144 wet sand samples and completed 4,999 interviews. Adjusted odds ratios (aORs) were computed, comparing those in the highest tertile of fecal indicator exposure with those who reported no sand contact. Among those digging in sand compared with those not digging in sand, a molecular measure of Enterococcus spp. (calibrator cell equivalents/g) in sand was positively associated with gastrointestinal (GI) illness (aOR = 2.0 [95% confidence interval (CI) = 1.2–3.2]) and diarrhea (2.4 [1.4–4.2]). Among those buried in sand, point estimates were greater for GI illness (3.3 [1.3–7.9]) and diarrhea (4.9 [1.8–13]). Positive associations were also observed for culture-based Enterococcus (colony-forming units/g) with GI illness (aOR digging = 1.7 [1.1–2.7]) and diarrhea (2.1 [1.3–3.4]). Associations were not found among non-swimmers with sand exposure. Conclusions We observed a positive relationship between sand contact activities and enteric illness as a function of concentrations of fecal microbial pollution in beach sand. PMID:22157306

Combating Gangs: Better Coordination and Performance Measurement Would Help Clarify Roles of Federal Agencies and Strengthen Assessment of Efforts. Report to the Ranking Member, Committee on Oversight and Government Reform, House of Representatives. GAO-09-708

ERIC Educational Resources Information Center

US Government Accountability Office, 2009

2009-01-01

The Department of Justice (DOJ) estimates that the United States has about a million gang members. While state and local agencies have primary responsibility for combating gang crime, the federal government has key roles to enforce laws and help fund programs to provide alternatives to gang membership for at-risk youth. GAO was asked to examine…

Climatic variation and runoff from partially-glacierised Himalayan tributary basins of the Ganges.

PubMed

Collins, David N; Davenport, Joshua L; Stoffel, Markus

2013-12-01

Climate records for locations across the southern slope of the Himalaya between 77°E and 91°E were selected together with discharge measurements from gauging stations on rivers draining partially-glacierised basins tributary to the Ganges, with a view to assessing impacts of climatic fluctuations on year-to-year variations of runoff during a sustained period of glacier decline. The aims were to describe temporal patterns of variation of glaciologically- and hydrologically-relevant climatic variables and of river flows from basins with differing percentages of ice-cover. Monthly precipitation and air temperature records, starting in the mid-nineteenth century at high elevation sites and minimising data gaps, were selected from stations in the Global Historical Climatology Network and CRUTEM3. Discharge data availability was limited to post 1960 for stations in Nepal and at Khab in the adjacent Sutlej basin. Strengths of climate-runoff relationships were assessed by correlation between overlapping portions of annual data records. Summer monsoon precipitation dominates runoff across the central Himalaya. Flow in tributaries of the Ganges in Nepal fluctuated from year to year but the general background level of flow was usually maintained from the 1960s to 2000s. Flow in the Sutlej, however, declined by 32% between the 1970s and 1990s, reflecting substantially reduced summer precipitation. Over the north-west Ganges-upper Sutlej area, monsoon precipitation declined by 30-40% from the 1960s to 2000s. Mean May-September air temperatures along the southern slope of the central Himalayas dipped from the 1960s, after a long period of slow warming or sustained temperatures, before rising rapidly from the mid-1970s so that in the 2000s summer air temperatures reached those achieved in earlier warmer periods. There are few measurements of runoff from highly-glacierised Himalayan headwater basins; runoff from one of which, Langtang Khola, was less than that of the monsoon

Industrial sand and gravel

USGS Publications Warehouse

Dolley, T.P.

2012-01-01

Domestic production of industrial sand and gravel in 2011 was about 30 Mt (33 million st), increasing slightly compared with 2010. Some important end uses for industrial sand and gravel include abrasives, filtration, foundry, glassmaking, hydraulic fracturing sand (frac sand) and silicon metal applications.

Bullies, Gangs, Drugs, and School: Understanding the Overlap and the Role of Ethnicity and Urbanicity

ERIC Educational Resources Information Center

Bradshaw, Catherine P.; Waasdorp, Tracy Evian; Goldweber, Asha; Johnson, Sarah Lindstrom

2013-01-01

Recent media attention has increased interest in behavioral, mental health, and academic correlates of involvement in bullying. Yet, there has not been much interest in investigating the co-occurrence of other health-risk behaviors, such as gang membership, weapon carrying, and substance use. The potential influence of contextual factors, such as…

Public School Uniforms: Effect on Perceptions of Gang Presence, School Climate, and Student Self-Perceptions.

ERIC Educational Resources Information Center

Wade, Kathleen Kiley; Stafford, Mary E.

2003-01-01

Examined the relationship between public school uniforms and student self-worth and student and staff perceptions of gang presence and school climate. Surveys of middle school students and teachers indicated that although students' perceptions did not vary across uniform policy, teachers from schools with uniform policies perceived lower levels of…

Flood Risk Assessment and Forecasting for the Ganges-Brahmaputra-Meghna River Basins

NASA Astrophysics Data System (ADS)

Hopson, T. M.; Priya, S.; Young, W.; Avasthi, A.; Clayton, T. D.; Brakenridge, G. R.; Birkett, C. M.; Riddle, E. E.; Broman, D.; Boehnert, J.; Sampson, K. M.; Kettner, A.; Singh, D.

2017-12-01

During the 2017 South Asia monsoon, torrential rains and catastrophic floods affected more than 45 million people, including 16 million children, across the Ganges-Brahmaputra-Meghna (GBM) basins. The basin is recognized as one of the world's most disaster-prone regions, with severe floods occurring almost annually causing extreme loss of life and property. In light of this vulnerability, the World Bank and collaborators have contributed toward reducing future flood impacts through recent developments to improve operational preparedness for such events, as well as efforts in more general preparedness and resilience building through planning based on detailed risk assessments. With respect to improved event-specific flood preparedness through operational warnings, we discuss a new forecasting system that provides probability-based flood forecasts developed for more than 85 GBM locations. Forecasts are available online, along with near-real-time data maps of rainfall (predicted and actual) and river levels. The new system uses multiple data sets and multiple models to enhance forecasting skill, and provides improved forecasts up to 16 days in advance of the arrival of high waters. These longer lead times provide the opportunity to save both lives and livelihoods. With sufficient advance notice, for example, farmers can harvest a threatened rice crop or move vulnerable livestock to higher ground. Importantly, the forecasts not only predict future water levels but indicate the level of confidence in each forecast. Knowing whether the probability of a danger-level flood is 10 percent or 90 percent helps people to decide what, if any, action to take. With respect to efforts in general preparedness and resilience building, we also present a recent flood risk assessment, and how it provides, for the first time, a numbers-based view of the impacts of different size floods across the Ganges basin. The findings help identify priority areas for tackling flood risks (for

Dunes in Nectaris Montes

NASA Image and Video Library

2018-05-14

This image from NASA's Mars Reconnaissance Orbiter (MRO) shows some of these on the slopes of Nectaris Montes within Coprates Chasma. Sand dunes in Valles Marineris can be impressive in size, with steep slopes that seem to climb and descend. The brighter bedforms are inactive while the bigger dunes move over the landscape, burying and exhuming the surface. https://photojournal.jpl.nasa.gov/catalog/PIA22455

Industrial sand and gravel

USGS Publications Warehouse

Dolley, T.P.

2013-01-01

Domestic production of industrial sand and gravel in 2012 was about 49.5 Mt (55 million st), increasing 13 percent compared with that of 2011. Some important end uses for industrial sand and gravel include abrasives, filtration, foundry, glassmaking, hydraulic fracturing sand (frac sand) and silicon metal applications.

Morphology and composition of the surface of Mars: Mars Odyssey THEMIS results.

PubMed

Christensen, Philip R; Bandfield, Joshua L; Bell, James F; Gorelick, Noel; Hamilton, Victoria E; Ivanov, Anton; Jakosky, Bruce M; Kieffer, Hugh H; Lane, Melissa D; Malin, Michael C; McConnochie, Timothy; McEwen, Alfred S; McSween, Harry Y; Mehall, Greg L; Moersch, Jeffery E; Nealson, Kenneth H; Rice, James W; Richardson, Mark I; Ruff, Steven W; Smith, Michael D; Titus, Timothy N; Wyatt, Michael B

2003-06-27

The Thermal Emission Imaging System (THEMIS) on Mars Odyssey has produced infrared to visible wavelength images of the martian surface that show lithologically distinct layers with variable thickness, implying temporal changes in the processes or environments during or after their formation. Kilometer-scale exposures of bedrock are observed; elsewhere airfall dust completely mantles the surface over thousands of square kilometers. Mars has compositional variations at 100-meter scales, for example, an exposure of olivine-rich basalt in the walls of Ganges Chasma. Thermally distinct ejecta facies occur around some craters with variations associated with crater age. Polar observations have identified temporal patches of water frost in the north polar cap. No thermal signatures associated with endogenic heat sources have been identified.

Morphology and composition of the surface of Mars: Mars Odyssey THEMIS results

USGS Publications Warehouse

Christensen, P.R.; Bandfield, J.L.; Bell, J.F.; Gorelick, N.; Hamilton, V.E.; Ivanov, A.; Jakosky, B.M.; Kieffer, H.H.; Lane, M.D.; Malin, M.C.; McConnochie, T.; McEwen, A.S.; McSween, H.Y.; Mehall, G.L.; Moersch, J.E.; Nealson, K.H.; Rice, J. W.; Richardson, M.I.; Ruff, S.W.; Smith, M.D.; Titus, T.N.; Wyatt, M.B.

2003-01-01

The Thermal Emission Imaging System (THEMIS) on Mars Odyssey has produced infrared to visible wavelength images of the martian surface that show lithologically distinct layers with variable thickness, implying temporal changes in the processes or environments during or after their formation. Kilometer-scale exposures of bedrock are observed; elsewhere airfall dust completely mantles the surface over thousands of square kilometers. Mars has compositional variations at 100-meter scales, for example, an exposure of olivine-rich basalt in the walls of Ganges Chasma. Thermally distinct ejecta facies occur around some craters with variations associated with crater age. Polar observations have identified temporal patches of water frost in the north polar cap. No thermal signatures associated with endogenic heat sources have been identified.

Ethnic Identity and Offending Trajectories among Mexican American Juvenile Offenders: Gang Membership and Psychosocial Maturity

ERIC Educational Resources Information Center

Knight, George P.; Losoya, Sandra H.; Cho, Young Il; Chassin, Laurie; Williams, Joanna Lee; Cota-Robles, Sonia

2012-01-01

We examined the association of joint trajectories of ethnic identity and criminal offending to psychosocial maturity, gang membership, and Mexican American affiliation among 300 Mexican American male juvenile offenders from ages 14 to 22. There were two low-offending groups: one was the highest in ethnic identity and changing slightly with age and…

Broadband Scattering from Sand and Sand/Mud Sediments with Extensive Environmental Characterization

DTIC Science & Technology

2015-09-30

1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Broadband Scattering from Sand and Sand/ Mud Sediments...TERM GOALS To model the effects of volume heterogeneities, both discrete and continuous, in scattering from sand and mud sediments. A better...IMP2 has been used extensively during TREX13 and BayEx14 to measure the porosity in both sand and mud sediments. Analysis of this recent data inspired a

Paradoxical Outcomes in an Educational Drama about Gang Rape: Ethical Responsibilities of Practitioners and Educators

ERIC Educational Resources Information Center

Gesser-Edelsburg, Anat

2005-01-01

Educational drama has been embraced as a promising way to address sensitive and highly-charged issues among youth. An Israeli drama, "Backyard Games", about gang rape, based on an actual case in a kibbutz [a communal settlement] called Shomrat, is considered the definitive work on the subject in Israeli theatre. Written by Edna Mazya and…

Sand Filter Technology

DTIC Science & Technology

2016-08-01

Approved for public release: distribution unlimited TDS-NAVFAC-EXWC-PW-1604 Aug 2016 Sand Filter Technology This report summarizes the...findings from a demonstration of sand filter technology to determine whether the technology will save energy with a simple payback within the...EXWC) performed the evaluation at the Naval Air Station Lemoore, CA. The two year evaluation period began with one year of sand filter operation

Threshold for sand mobility on Mars calibrated from seasonal variations of sand flux.

PubMed

Ayoub, F; Avouac, J-P; Newman, C E; Richardson, M I; Lucas, A; Leprince, S; Bridges, N T

2014-09-30

Coupling between surface winds and saltation is a fundamental factor governing geological activity and climate on Mars. Saltation of sand is crucial for both erosion of the surface and dust lifting into the atmosphere. Wind tunnel experiments along with measurements from surface meteorology stations and modelling of wind speeds suggest that winds should only rarely move sand on Mars. However, evidence for currently active dune migration has recently accumulated. Crucially, the frequency of sand-moving events and the implied threshold wind stresses for saltation have remained unknown. Here we present detailed measurements of Nili Patera dune field based on High Resolution Imaging Science Experiment images, demonstrating that sand motion occurs daily throughout much of the year and that the resulting sand flux is strongly seasonal. Analysis of the seasonal sand flux variation suggests an effective threshold for sand motion for application to large-scale model wind fields (1-100 km scale) of τ(s)=0.01±0.0015 N m(-2).

Saltation of Non-Spherical Sand Particles

PubMed Central

Wang, Zhengshi; Ren, Shan; Huang, Ning

2014-01-01

Saltation is an important geological process and the primary source of atmospheric mineral dust aerosols. Unfortunately, no studies to date have been able to precisely reproduce the saltation process because of the simplified theoretical models used. For example, sand particles in most of the existing wind sand movement models are considered to be spherical, the effects of the sand shape on the structure of the wind sand flow are rarely studied, and the effect of mid-air collision is usually neglected. In fact, sand grains are rarely round in natural environments. In this paper, we first analyzed the drag coefficients, drag forces, and starting friction wind speeds of sand grains with different shapes in the saltation process, then established a sand saltation model that considers the coupling effect between wind and the sand grains, the effect of the mid-air collision of sand grains, and the effect of the sand grain shape. Based on this model, the saltation process and sand transport rate of non-spherical sand particles were simulated. The results show that the sand shape has a significant impact on the saltation process; for the same wind speed, the sand transport rates varied for different shapes of sand grains by as much as several-fold. Therefore, sand shape is one of the important factors affecting wind-sand movement. PMID:25170614

Global sand trade is paving the way for a tragedy of the sand commons

NASA Astrophysics Data System (ADS)

Torres, A.; Brandt, J.; Lear, K.; Liu, J.

2016-12-01

In the first 40 years of the 21st century, planet Earth is highly likely to experience more urban land expansion than in all of history, an increase in transportation infrastructure by more than a third, and a great variety of land reclamation projects. While scientists are beginning to quantify the deep imprint of human infrastructure on biodiversity at large scales, its off-site impacts and linkages to sand mining and trade have been largely ignored. Sand is the most widely used building material in the world. With an ever-increasing demand for this resource, sand is being extracted at rates that far exceed its replenishment, and is becoming increasingly scarce. This has already led to conflicts around the world and will likely lead to a "tragedy of the sand commons" if sustainable sand mining and trade cannot be achieved. We investigate the environmental and socioeconomic interactions over large distances (telecouplings) of infrastructure development and sand mining and trade across diverse systems through transdisciplinary research and the recently proposed telecoupling framework. Our research is generating a thorough understanding of the telecouplings driven by an increasing demand for sand. In particular, we address three main research questions: 1) Where are the conflicts related to sand mining occurring?; 2) What are the major "sending" and "receiving" systems of sand?; and 3) What are the main components (e.g. causes, effects, agents, etc.) of telecoupled systems involving sand mining and trade? Our results highlight the role of global sand trade as a driver of environmental degradation that threatens the integrity of natural systems and their capacity to deliver key ecosystem services. In addition, infrastructure development and sand mining and trade have important implications for other sustainability challenges such as over-fishing and global warming. This knowledge will help to identify opportunities and tools to better promote a more sustainable use

Chain Gang-The Chemistry of Polymers (edited by Mickey Sarquis)

NASA Astrophysics Data System (ADS)

Collard, David M.

1999-01-01

Science in Our World, Vol. 5. Mickey Sarquis, series editor. Terrific Science Press: Middletown, OH, 1995. xiv + 149 pp. ISBN 1-883822-13-0. Spiral-bound, $13.95. Our familiarity with plastics makes polymers ideal examples of chemicals for discussion in K-12 science classes. Most importantly, polymers can be used as examples of chemicals that are safe to handle and of obvious use to society. The structures of polymers are easily represented by a number of models. These simple models go a long way in explaining the familiar physical properties of plastics. However, the introduction of polymers in the classroom relies on the availability of teaching material, experiments, and demonstrations that illustrate concepts in the current science curriculum. Chain Gang-The Chemistry of Polymers, one of the Science in Our World series published by the Center for Chemical Education at Miami University-Middletown (Ohio), will serve as a great resource for teachers interested in providing their students with a series of activities that can be related to their everyday experiences with these ubiquitous chemicals. After a brief introduction to some basic concepts, the book presents a series of 23 experiments. The collection of experiments presented here spans illustrations of chemistry, physical properties, analysis, and processing. Each experiment is recommended as either a hands-on activity or demonstration for various grade levels. A guide for the teacher suggests how the experiment can be used to illustrate topics in the science curriculum. The materials required for each activity are listed in detail, with quantities and sources (all materials are available from Flinn Scientific or hardware stores). There are detailed instructions for preparation of each experiment and how to introduce the experiment to students, and step-by-step instructions for activity. Very importantly, safety and disposal issues are clearly presented. Suggestions for cross-curriculum integration are also

The Etiology of Female Juvenile Delinquency and Gang Membership: A Test of Psychological and Social Structural Explanations.

ERIC Educational Resources Information Center

Bowker, Lee H.; Klein, Malcolm W.

1983-01-01

Examined female delinquency and gang membership in 122 black female juveniles using data from the 1960s. Concluded that racism, sexism, poverty, and limited opportunity are more important predictors of delinquency than personality and family relationships. Relationships with girl friends were more significant predictors than heterosexual…

Effect on water resources from upstream water diversion in the Ganges basin.

PubMed

Adel, M M

2001-01-01

Bangladesh faces at least 30 upstream water diversion constructions of which Farakka Barrage is the major one. The effects of Farakka Barrage on water resources, socioeconomy, and culture have been investigated downstream in the basins of the Ganges and its distributaries. A diversion of up to 60% of the Ganges water over 25 yr has caused (i) reduction of water in surface water resources, (ii) increased dependence on ground water, (iii) destruction of the breeding and raising grounds for 109 species of Gangetic fishes and other aquatic species and amphibians, (iv) increased malnutrition, (v) deficiency in soil organic matter content, (vi) change in the agricultural practices, (vii) eradication of inland navigable routes, (viii) outbreak of waterborne diseases, (ix) loss of professions, and (x) obstruction to religious observances and pastimes. Further, arsenopyrites buried in the prebarrage water table have come in contact with air and formed water-soluble compounds of arsenic. Inadequate recharging of ground water hinders the natural cleansing of arsenic, and threatens about 75,000,000 lives who are likely to use water contaminated with up to 2 mg/L of arsenic. Furthermore, the depletion of surface water resources has caused environmental heating and cooling effects. Apart from these effects, sudden releases of water by the barrage during the flood season cause devestating floods. In consideration of such a heavy toll for the areas downstream, strict international rules have to be laid down to preserve the riparian ecosystems.

Ius Chasma by Day and Night

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site]

Released 18 June 2004 This pair of images shows part of Ius Chasma.

Day/Night Infrared Pairs

The image pairs presented focus on a single surface feature as seen in both the daytime and nighttime by the infrared THEMIS camera. The nighttime image (right) has been rotated 180 degrees to place north at the top.

Infrared image interpretation

Daytime: Infrared images taken during the daytime exhibit both the morphological and thermophysical properties of the surface of Mars. Morphologic details are visible due to the effect of sun-facing slopes receiving more energy than antisun-facing slopes. This creates a warm (bright) slope and cool (dark) slope appearance that mimics the light and shadows of a visible wavelength image. Thermophysical properties are seen in that dust heats up more quickly than rocks. Thus dusty areas are bright and rocky areas are dark.

Nighttime: Infrared images taken during the nighttime exhibit only the thermophysical properties of the surface of Mars. The effect of sun-facing versus non-sun-facing energy dissipates quickly at night. Thermophysical effects dominate as different surfaces cool at different rates through the nighttime hours. Rocks cool slowly, and are therefore relatively bright at night (remember that rocks are dark during the day). Dust and other fine grained materials cool very quickly and are dark in nighttime infrared images.

Image information: IR instrument. Latitude -1, Longitude 276 East (84 West). 100 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the

Flexible Strategies for Coping with Rainfall Variability: Seasonal Adjustments in Cropped Area in the Ganges Basin

PubMed Central

Siderius, Christian; Biemans, Hester; van Walsum, Paul E. V.; van Ierland, Ekko C.; Kabat, Pavel; Hellegers, Petra J. G. J.

2016-01-01

One of the main manifestations of climate change will be increased rainfall variability. How to deal with this in agriculture will be a major societal challenge. In this paper we explore flexibility in land use, through deliberate seasonal adjustments in cropped area, as a specific strategy for coping with rainfall variability. Such adjustments are not incorporated in hydro-meteorological crop models commonly used for food security analyses. Our paper contributes to the literature by making a comprehensive model assessment of inter-annual variability in crop production, including both variations in crop yield and cropped area. The Ganges basin is used as a case study. First, we assessed the contribution of cropped area variability to overall variability in rice and wheat production by applying hierarchical partitioning on time-series of agricultural statistics. We then introduced cropped area as an endogenous decision variable in a hydro-economic optimization model (WaterWise), coupled to a hydrology-vegetation model (LPJmL), and analyzed to what extent its performance in the estimation of inter-annual variability in crop production improved. From the statistics, we found that in the period 1999–2009 seasonal adjustment in cropped area can explain almost 50% of variability in wheat production and 40% of variability in rice production in the Indian part of the Ganges basin. Our improved model was well capable of mimicking existing variability at different spatial aggregation levels, especially for wheat. The value of flexibility, i.e. the foregone costs of choosing not to crop in years when water is scarce, was quantified at 4% of gross margin of wheat in the Indian part of the Ganges basin and as high as 34% of gross margin of wheat in the drought-prone state of Rajasthan. We argue that flexibility in land use is an important coping strategy to rainfall variability in water stressed regions. PMID:26934389

The Role of Professional School Counselors in Working with Students in Gangs: A Grounded Theory Study

ERIC Educational Resources Information Center

Barrow, Jennifer Cahoon

2011-01-01

The purpose of this study was to propose a grounded theory that contributed to the understanding of the professional school counselor's role at the secondary school level in working with students in gangs. The study explored the role of the professional school counselor from the first person perspective of the professional school counselor and…

Reviving the "Ganges Water Machine": where and how much?

NASA Astrophysics Data System (ADS)

Muthuwatta, Lal; Amarasinghe, Upali A.; Sood, Aditya; Surinaidu, Lagudu

2017-05-01

Runoff generated in the monsoon months in the upstream parts of the Ganges River basin (GRB) contributes substantially to downstream floods, while water shortages in the dry months affect agricultural production in the basin. This paper examines the potential for subsurface storage (SSS) in the Ganges basin to mitigate floods in the downstream areas and increase the availability of water during drier months. The Soil and Water Assessment Tool (SWAT) is used to estimate sub-basin water availability. The water availability estimated is then compared with the sub-basin-wise unmet water demand for agriculture. Hydrological analysis reveals that some of the unmet water demand in the sub-basin can be met provided it is possible to capture the runoff in sub-surface storage during the monsoon season (June to September). Some of the groundwater recharge is returned to the stream as baseflow and has the potential to increase dry season river flows. To examine the impacts of groundwater recharge on flood inundation and flows in the dry season (October to May), two groundwater recharge scenarios are tested in the Ramganga sub-basin. Increasing groundwater recharge by 35 and 65 % of the current level would increase the baseflow during the dry season by 1.46 billion m3 (34.5 % of the baseline) and 3.01 billion m3 (71.3 % of the baseline), respectively. Analysis of pumping scenarios indicates that 80 000 to 112 000 ha of additional wheat area can be irrigated in the Ramganga sub-basin by additional SSS without reducing the current baseflow volumes. Augmenting SSS reduces the peak flow and flood inundated areas in Ramganga (by up to 13.0 % for the 65 % scenario compared to the baseline), indicating the effectiveness of SSS in reducing areas inundated under floods in the sub-basin. However, this may not be sufficient to effectively control the flood in the downstream areas of the GRB, such as in the state of Bihar (prone to floods), which receives a total flow of 277 billion

Nature of distribution of mercury in the sediments of the river Yamuna (tributary of the Ganges), India.

PubMed

Subramanian, V; Madhavan, N; Saxena, Rajinder; Lundin, Lars-Christer

2003-06-01

Suspended Particulate Matter (SPM), surface (bed sediments) and short length cores of sediments collected from the largest tributary of the river Ganges, namely the river Yamuna, were analysed for total mercury as well as its fractionation in various size and chemical sites in the sediments following standard procedures. Also, attempts were made to determine the vertical distribution in sediments in relation to the recent timescale of a few decades. Our observations indicate that the SPM in general showed higher levels of total mercury compared to the surface sediments while at places the enhancement could be by a factor of 10, say around 25 microg g(-1) in the downstream region that integrates the industrial midstream and agricultural downstream terrain near its confluence with the Ganges. Surface sediments in the upstream direction near the Himalayan foothills and SPM in the lower reaches showed significant high Index of Geoaccumulation (Igeo) as defined by Müller. Size fractionation studies indicate that the finer fraction preferentially showed higher levels of mercury while in the lower reaches of the river, the total mercury is equitably distributed among all size fractions. The proportion of the residual fraction of mercury in relation to mobile fractions, in general decreases downstream towards its confluence with the Ganges river. In sediment cores, the vertical distribution show systematic peaks of mercury indicating that addition of this toxic metal to the aquatic system is in direct proportion to the increase in various types of human activities such as thermal power plants, land use changes (urbanisation) in the midstream region and intensive fertiliser application in lower reaches of this vast river basin.

Ganges Valley Aerosol Experiment (GVAX) Final Campaign Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kotamarthi, VR

2013-12-01

In general, the Indian Summer Monsoon (ISM) as well as the and the tropical monsoon climate is influenced by a wide range of factors. Under various climate change scenarios, temperatures over land and into the mid troposphere are expected to increase, intensifying the summer pressure gradient differential between land and ocean and thus strengthening the ISM. However, increasing aerosol concentration, air pollution, and deforestation result in changes to surface albedo and insolation, potentially leading to low monsoon rainfall. Clear evidence points to increasing aerosol concentrations over the Indian subcontinent with time, and several hypotheses regarding the effect on monsoons havemore » been offered. The Ganges Valley Aerosol Experiment (GVAX) field study aimed to provide critical data to address these hypotheses and contribute to developing better parameterizations for tropical clouds, convection, and aerosol-cloud interactions. The primary science questions for the mission were as follows:« less

Experimental investigation of cephapirin adsorption to quartz filter sands and dune sands

NASA Astrophysics Data System (ADS)

Peterson, Jonathan W.; O'Meara, Theresa A.; Seymour, Michael D.

2008-08-01

Batch experiments were performed to investigate cephapirin (a widely used veterinary antibiotic) adsorption on various size sands of low total organic carbon content (0.08-0.36 wt%). In the aqueous concentration range investigated (11-112 μmol/L cephapirin), adsorption to nearly pure quartz filter sands (0.50-3.35 mm diameter) is low. Isotherms are S-shaped and most display a region of minimum adsorption, where decreased adsorption occurs with increasing solution concentration, followed by increased adsorption at higher concentrations. Cephapirin adsorption to quartz-rich, feldspar-bearing dune sands (0.06-0.35 mm diameter), and the smallest quartz filter sand investigated (0.43-0.50 mm), can be described by linear sorption isotherms over the range of concentrations investigated. Distribution coefficients ( K d) range from 0.94 to 3.45 L/kg. No systematic relationship exists between grain size and amount of adsorption for any of the sands investigated. Cephapirin adsorption is positively correlated to the feldspar ratio (K-feldspar/(albite + Ca-plagioclase). Feldspar-ratio normalization of distribution coefficients was more effective than organic carbon normalization at reducing variability of K d values in the dune sands investigated.

Sand pulses and sand patches on the Colorado River in Grand Canyon

USGS Publications Warehouse

Grams, Paul E.; Buscombe, Daniel; Topping, David; Mueller, Erich R.

2017-01-01

Alluvial sandbars occur in lateral recirculation zones (eddies) along the Colorado River in Grand Canyon National Park (Schmidt, 1990). Resource managers periodically release controlled floods from the upstream Glen Canyon Dam to rebuild these bars (Grams et al., 2015), which erode during fluctuating dam releases, and by hillslope runoff and wind deflation (Hazel et al., 2010). Because the dam blocks upstream sediment, episodic floods from tributaries provide the only supply to replace eroded sand; and much of this sand originates from a single tributary (Topping et al., 2000). Here, we present new evidence for the downstream translation of the sand component of these sediment inputs as discontinuous sand pulses. Improved understanding of the behaviour of these sand pulses may be used to adjust the timing, magnitude, and duration of controlled floods to maximize potential for deposition on sandbars in different segments of the 450 km-long Grand Canyon.

Monitoring Sand Sheets and Dunes

NASA Image and Video Library

2017-06-12

NASA's Mars Reconnaissance Orbiter (MRO) captured this crater featuring sand dunes and sand sheets on its floor. What are sand sheets? Snow fall on Earth is a good example of sand sheets: when it snows, the ground gets blanketed with up to a few meters of snow. The snow mantles the ground and "mimics" the underlying topography. Sand sheets likewise mantle the ground as a relatively thin deposit. This kind of environment has been monitored by HiRISE since 2007 to look for movement in the ripples covering the dunes and sheets. This is how scientists who study wind-blown sand can track the amount of sand moving through the area and possibly where the sand came from. Using the present environment is crucial to understanding the past: sand dunes, sheets, and ripples sometimes become preserved as sandstone and contain clues as to how they were deposited The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 25 centimeters (9.8 inches) per pixel (with 1 x 1 binning); objects on the order of 75 centimeters (29.5 inches) across are resolved.] North is up. https://photojournal.jpl.nasa.gov/catalog/PIA21757

Altitude of the top of the Sparta Sand and Memphis Sand in three areas of Arkansas

USGS Publications Warehouse

Pugh, Aaron L.; Westerfield, Paul W.; Gonthier, Gerard; Poynter, David T.

1998-01-01

The Sparta Sand and Memphis Sand form the second most productive aquifer in Arkansas. The Sparta Sand and Memphis Sand range in thick- ness from 0 to 900 feet, consisting of fine- to medium-grained sands interbedded with layers of silt, clay, shale, and minor amounts of lignite. Within the three areas of interest, the top surface of the Sparta Sand and Memphis Sand dips regionally east and southeast towards the axis of the Mississippi Embayment syncline and Desha Basin. Local variations in the top surface may be attributed to a combination of continued development of structural features, differential compaction, localized faulting, and erosion of the surface prior to subsequent inundation and deposition of younger sediments.

Youth Violence and Gangs. Hearing on the Status of the Juvenile Justice System in America, Focusing on Activities of Youth Gangs and Their Access to Guns, and How Programs Can Help Prevent the Violence Associated with Youth Gangs, before the Subcommittee on Juvenile Justice of the Committee on the Judiciary. United States Senate, One Hundred Second Congress, First Session, (November 26, 1991).

ERIC Educational Resources Information Center

Congress of the U.S., Washington, DC. Senate Committee on the Judiciary.

The text of a Senate hearing on the status of youth gangs and their access to guns, and of violence prevention programs is provided in this document. Statements from Senators Herbert Kohl, Paul Simon, and Dennis DeConcini are presented. Testimony and prepared statements from these witnesses is included: (1) James Gabarino, president, Erikson…

Fecal indicators in sand, sand contact, and risk of enteric illness among beach-goers

EPA Science Inventory

BACKGROUND: Beach sand can harbor fecal indicator organisms and pathogens, but enteric illness risk associated with sand contact remains unclear. METHODS: In 2007, visitors at 2 recreational marine beaches were asked on the day of their visit about sand contact. Ten to 12 days...

Quantifying widespread aqueous surface weathering on Mars: The plateaus south of Coprates Chasma

NASA Astrophysics Data System (ADS)

Loizeau, D.; Quantin-Nataf, C.; Carter, J.; Flahaut, J.; Thollot, P.; Lozac'h, L.; Millot, C.

2018-03-01

Pedogenesis has been previously proposed on the plateaus around Coprates Chasma, Valles Marineris to explain the presence of widespread clay sequences with Al-clays and possible hydrated silica over Fe/Mg-clays on the surface of the plateaus (Le Deit et al., 2012; Carter et al., 2015). We use previous observations together with new MRO targeted observations and DEMs to constrain the extent and thickness of the plateau clay unit: the Al-clay unit is less than 3 m thick, likely ∼1 m, while the Fe/Mg-clays underneath are few tens of meters thick. We also refine the age of alteration by retrieving crater retention ages of the altered plateau and of later deposits: the observed clay sequence was created by surface pedogenesis between model ages of 4.1 Ga and 3.75 Ga. Using a leaching model from Zolotov and Mironenko (2016), we estimate the quantity of atmospheric precipitations needed to create such a clay sequence, that strongly depends on the chemistry of the precipitating fluid. A few hundreds of meters of cumulated precipitations of highly acidic fluids could explain the observed clay sequence, consistent with estimates based on late Noachian valley erosion for example (Rosenberg and Head, 2015). We show finally that the maximum quantity of sulfates potentially formed during this surface weathering event can only contribute minimally to the volume of sulfates deposited in Valles Marineris.

Increased Waterborne blaNDM-1 Resistance Gene Abundances Associated with Seasonal Human Pilgrimages to the Upper Ganges River

PubMed Central

2014-01-01

Antibiotic resistance (AR) is often rooted in inappropriate antibiotic use, but poor water quality and inadequate sanitation exacerbate the problem, especially in emerging countries. An example is increasing multi-AR due to mobile carbapenemases, such as NDM-1 protein (coded by blaNDM-1 genes), which can produce extreme drug-resistant phenotypes. In 2010, NDM-1 positive isolates and blaNDM-1 genes were detected in surface waters across Delhi and have since been detected across the urban world. However, little is known about blaNDM-1 levels in more pristine locations, such as the headwaters of the Upper Ganges River. This area is of particular interest because it receives massive numbers of visitors during seasonal pilgrimages in May/June, including visitors from urban India. Here we quantified blaNDM-1 abundances, other AR genes (ARG), and coliform bacteria in sediments and water column samples from seven sites in the Rishikesh-Haridwar region of the Upper Ganges and five sites on the Yamuna River in Delhi to contrast blaNDM-1 levels and water quality conditions between season and region. Water quality in the Yamuna was very poor (e.g., anoxia at all sites), and blaNDM-1 abundances were high across sites in water (5.4 ± 0.4 log(blaNDM-1·mL–1); 95% confidence interval) and sediment (6.3 ± 0.7 log(blaNDM-1·mg–1)) samples from both seasons. In contrast, water column blaNDM-1 abundances were very low across all sites in the Upper Ganges in February (2.1 ± 0.6 log(blaNDM-1·mL–1)), and water quality was good (e.g., near saturation oxygen). However, per capita blaNDM-1 levels were 20 times greater in June in the Ganges water column relative to February, and blaNDM-1 levels significantly correlated with fecal coliform levels (r = 0.61; p = 0.007). Given that waste management infrastructure is limited in Rishikesh-Haridwar, data imply blaNDM-1 levels are higher in visitor’s wastes than local residents, which results in seasonally higher blaNDM-1 levels in the

Scarcity of Fresh Water Resources in the Ganges Delta of Bangladesh

NASA Astrophysics Data System (ADS)

Murshed, S. B.; Kaluarachchi, J. J.

2017-12-01

The Ganges Delta in Bangladesh is a classical example of water insecurity in a transboundary river basin where limitations in quantity, quality and timing of available water is producing disastrous conditions. Two opposite extreme water conditions, i.e., fresh water scarcity and floods are common in this region during dry and wet seasons, respectively. The purpose of this study is to manage fresh water requirement of people and environment considering the seasonal availability of surface water (SW) and ground water (GW). SW availability was analyzed by incoming stream flow including the effects of upstream water diversion, rainfall, temperature, evapotranspiration (ET). Flow duration curves (FDC), and rainfall and temperature elasticity are used to assess the change of incoming upstream flow. Groundwater data were collected from 285 piezometers and monitoring wells established by Bangladesh water development board. Variation of groundwater depth shows major withdrawals of GW are mostly concentrated in the north part of the study area. Irrigation is the largest sector of off-stream (irrigation, industrial and domestic) water use which occupies 82% SW and 17% GW of total water consumption. Although domestic water use is entirely depend on GW but arsenic pollution is limiting the GW use. FDC depicts a substantial difference between high flow threshold (20%) and low flow threshold (70%) in the Bangladesh part of Ganges River. A large variation of around 83% is observed for instream water volume between wet and dry seasons. The reduction of upstream fresh water flow increased the extent and intensity of salinity intrusion. Presently GW is also contaminated by saline water. This fresh water scarcity is reducing the livelihood options considerably and indirectly forcing population migration from the delta region. This study provides insight to the changes in hydrology and limitations to freshwater availability enabling better formulation of water resources management in

Industrial sand and gravel

USGS Publications Warehouse

Dolley, T.P.

2006-01-01

In 2005, domestic production of industrial sand and gravel was about 31 Mt, a 5% increase from 2004. This increase was bouyed by robust construction and petroleum sectors of the US economy. Based on estimated world production figures, the United States was the world's leading producer and consumer of industrial sand and gravel. In the short term, local shortages of industrial sand and gravel will continue to increase.

[Environmental toxicity of waste foundry sand].

PubMed

Zhang, Hai-Feng; Wang, Yu-Jue; Wang, Jin-Lin; Huang, Tian-You; Xiong, Ying

2013-03-01

The metal leaching characteristics and volatile organic compounds (VOCs) of five different types of waste foundry sands were analyzed with the toxicity characteristic leaching procedure (TCLP) and head space-gas chromatography (HS-GC). Microtox and soil dehydrogenase activity (DHA) tests were then used to evaluate the bio-effects of these waste sands. The results showed that due to the different metals poured and casting materials used to make the sand molds, there was significant difference among the five waste foundry sands in the compositions and concentrations of metal and organic pollutants. The concentrations of Fe in the leachates of iron and steel casting waste foundry sand exceeded the maximal allowable concentrations specified in the National Standard of Drinking Water Quality, whereas the As concentration in the leachate of aluminum casting waste foundry sand exceeded the standard. The five waste foundry sands had quite different compositions and levels of VOCs, which resulted in different levels of inhibition effects on the luminescent bacteria (30% and 95%). Additionally, the soil DHA tests suggested that metal pollutants in waste foundry sands may inhibit the soil microbial activity, whereas organics in the sands may slightly promote the microbial activity. The results of this study indicated that the waste foundry sands may pose considerable threat to the environment when improperly disposed.

Compressive behavior of fine sand.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Bradley E.; Kabir, Md. E.; Song, Bo

2010-04-01

The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trendsmore » were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.« less

Spatial and seasonal responses of precipitation in the Ganges and Brahmaputra river basins to ENSO and Indian Ocean dipole modes: implications for flooding and drought

USGS Publications Warehouse

Pervez, Md Shahriar; Henebry, Geoffry M.

2015-01-01

We evaluated the spatial and seasonal responses of precipitation in the Ganges and Brahmaputra basins as modulated by the El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) modes using Global Precipitation Climatology Centre (GPCC) full data reanalysis of monthly global land-surface precipitation data from 1901 to 2010 with a spatial resolution of 0.5° × 0.5°. The GPCC monthly total precipitation climatology targeting the period 1951–2000 was used to compute gridded monthly anomalies for the entire time period. The gridded monthly anomalies were averaged for the years influenced by combinations of climate modes. Occurrences of El Niño alone significantly reduce (88% of the long-term average (LTA)) precipitation during the monsoon months in the western and southeastern Ganges Basin. In contrast, occurrences of La Niña and co-occurrences of La Niña and negative IOD events significantly enhance (110 and 109% of LTA in the Ganges and Brahmaputra Basin, respectively) precipitation across both basins. When El Niño co-occurs with positive IOD events, the impacts of El Niño on the basins' precipitation diminishes. When there is no active ENSO or IOD events (occurring in 41 out of 110 years), precipitation remains below average (95% of LTA) in the agriculturally intensive areas of Haryana, Uttar Pradesh, Rajasthan, Madhya Pradesh, and Western Nepal in the Ganges Basin, whereas precipitation remains average to above average (104% of LTA) across the Brahmaputra Basin. This pattern implies that a regular water deficit is likely, especially in the Ganges Basin, with implications for the agriculture sector due to its reliance on consistent rainfall for successful production. Historically, major droughts occurred during El Niño and co-occurrences of El Niño and positive IOD events, while major flooding occurred during La Niña and co-occurrences of La Niña and negative IOD events in the basins. This observational analysis will facilitate well

Sand Volcano Following Earthquake

NASA Technical Reports Server (NTRS)

1989-01-01

Sand boil or sand volcano measuring 2 m (6.6 ft.) in length erupted in median of Interstate Highway 80 west of the Bay Bridge toll plaza when ground shaking transformed loose water-saturated deposit of subsurface sand into a sand-water slurry (liquefaction) in the October 17, 1989, Loma Prieta earthquake. Vented sand contains marine-shell fragments. Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. Mechanics of Granular Materials (MGM) experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (Credit: J.C. Tinsley, U.S. Geological Survey)

Canaries in the coal mine: Interpersonal violence, gang violence, and violent extremism through a public health prevention lens.

PubMed

Eisenman, David P; Flavahan, Louise

2017-08-01

This paper asks what programmes and policies for preventing violent extremism (also called 'countering violent extremism', or CVE) can learn from the public health violence prevention field. The general answer is that addressing violent extremism within the wider domain of public health violence prevention connects the effort to a relevant field of research, evidence-based policy and programming, and a broader population reach. This answer is reached by examining conceptual alignments between the two fields at both the case-level and the theoretical level. To address extremist violence within the wider reach of violence prevention, having a shared model is seen as a first step. The World Health Organization uses the social-ecological framework for assessing the risk and protective factors for violence and developing effective public-health based programmes. This study illustrates how this model has been used for gang violence prevention and explores overlaps between gang violence prevention and preventing violent extremism. Finally, it provides policy and programme recommendations to align CVE with public health violence prevention.

Industrial sand and gravel

USGS Publications Warehouse

Dolley, T.P.

2010-01-01

Domestic production of industrial sand and gravel in 2009 was about 27 Mt (30 million st), declining by 10 percent compared with 2008. Certain end uses of industrial sand and gravel, such as foundry and glassmaking sand, may have declined by a factor greater than 10 percent in 2009. U.S. apparent consumption was 24.7 Mt (27.2 million st) in 2009, down by 10 percent from the previous year, and imports declined to 83 kt (91,000 st).

A High Resolution Look at Black Sand Particles from Sand Dunes of Saudi Arabia Using Electron Microscopy

NASA Astrophysics Data System (ADS)

Hussain, M. M.; Aburizaiza, O. S.; Siddique, A.; Hershey, D. L.; Guerrieri, D. A.; Qurashi, J.; Abbass, M.; Blake, D. R.; Khwaja, H. A.

2013-12-01

Particulate air pollution is a problem of health concern. The microscopic make-up of different varieties of sand particles found and collected at a sand dune site in Badr, Saudi Arabia has been determined. Primary emphasis is given to the use of multiple high resolution electron microscopy (viz., Scanning Electron Microscopy with Energy Dispersive X-ray spectrometry (SEM/EDS) and Laser Scanning Microscopy (LSM)) to study the morphologies, emission source types, size, and elemental composition of the particles, and to evaluate the presence of ';coatings or contaminants' adsorbed or carried on by the black sand particles. White sand contains natural coarse particles associated with wind-blown releases from crustal surfaces, weathering of an igneous/metamorphic rock source, and volcanic activities. Silicates (alumino-silicates) and quartz (clear, milky, rose) dominate white sand and rest appears to contain calcite, olivine, feldspar, and magnetite. Black sand particles exhibit very different morphologies and microstructures (surface roughness) compared with white sand and volcanic ash. Morphological analyses have shown that the black sand contain ultrafine particles. Black sand is strongly magnetic, which indicates the mineral magnetite (strongly magnetic) or elemental iron. Iron, C, O, Ti, Si, V, and S particles dominate the black sand. Natural and anthropogenic sources have been implicated for the observed particles. Analysis revealed that the surface of white sand particles is mainly covered with the fine particles. It is known that emissions from combustion contain carbon soot and other contaminants that are easily absorbed by soil particles during a long-range transport.

Microbial strengthening of loose sand.

PubMed

Banagan, B L; Wertheim, B M; Roth, M J S; Caslake, L F

2010-08-01

To test whether the addition of Flavobacterium johnsoniae could increase the strength of saturated Ottawa 30 sand. A box model was built that simulates groundwater-like flow through a main sand compartment. Strength tests were performed at seven locations and at two depths, 10.8 and 20.3 cm below the top of the tank, using a vane shear device before and after the addition of bacteria. After the addition of Fl. johnsoniae, sand samples were obtained from multiple sampling ports on the vertical sides of the box model. The presence of a bacterial biofilm was confirmed by staining these sand samples with SYTO-9 and Alexa Fluor 633 and viewing with a confocal microscope. The average shear strength increases after the addition of Fl. johnsoniae were 15.2-87.5%, depending on the experimental conditions. Flavobacterium johnsoniae caused a statistically significant increase in the strength of saturated Ottawa 30 sand. Biofilm-forming bacteria can increase the shear strength of saturated sand. The addition of biofilm-forming bacteria to a building site may be an alternate method to mitigate the effects of liquefaction.

Relationships with Adults as Predictors of Substance Use, Gang Involvement, and Threats to Safety among Disadvantaged Urban High-School Adolescents

ERIC Educational Resources Information Center

Ryan, Linda G.; Miller-Loessi, Karen; Nieri, Tanya

2007-01-01

Using a resilience framework, the authors examined the protective effects of parental support, self-disclosure to parents, parent-initiated monitoring of adolescent behavior, and relationships with school personnel on three critical problems of adolescents: substance use, gang involvement, and perceived threats to safety at school. The sample…

Model study of the impacts of future climate change on the hydrology of Ganges-Brahmaputra-Meghna (GBM) basin

NASA Astrophysics Data System (ADS)

Masood, M.; Yeh, P. J.-F.; Hanasaki, N.; Takeuchi, K.

2014-06-01

The intensity, duration, and geographic extent of floods in Bangladesh mostly depend on the combined influences of three river systems, Ganges, Brahmaputra and Meghna (GBM). In addition, climate change is likely to have significant effects on the hydrology and water resources of the GBM basins and might ultimately lead to more serious floods in Bangladesh. However, the assessment of climate change impacts on basin-scale hydrology by using well-constrained hydrologic modelling has rarely been conducted for GBM basins due to the lack of data for model calibration and validation. In this study, a macro-scale hydrologic model H08 has been applied regionally over the basin at a relatively fine grid resolution (10 km) by integrating the fine-resolution (~0.5 km) DEM data for accurate river networks delineation. The model has been calibrated via analyzing model parameter sensitivity and validated based on a long-term observed daily streamflow data. The impact of climate change on not only the runoff, but also the basin-scale hydrology including evapotranspiration, soil moisture and net radiation have been assessed in this study through three time-slice experiments; present-day (1979-2003), near-future (2015-2039) and far-future (2075-2099) periods. Results shows that, by the end of 21st century (a) the entire GBM basin is projected to be warmed by ~3°C (b) the changes of mean precipitation are projected to be +14.0, +10.4, and +15.2%, and the changes of mean runoff to be +14, +15, and +18% in the Brahmaputra, Ganges and Meghna basin respectively (c) evapotranspiration is predicted to increase significantly for the entire GBM basins (Brahmaputra: +14.4%, Ganges: +9.4%, Meghna: +8.8%) due to increased net radiation (Brahmaputra: +6%, Ganges: +5.9%, Meghna: +3.3%) as well as warmer air temperature. Changes of hydrologic variables will be larger in dry season (November-April) than that in wet season (May-October). Amongst three basins, Meghna shows the largest hydrological

Epidemiological criminology: drug use among African American gang members.

PubMed

Lanier, Mark M; Pack, Robert P; Akers, Timothy A

2010-01-01

Epidemiological methods and public health theories can be tied to theories of crime and delinquency and used to create evidence-based policy. Interdisciplinary theoretical approaches to existing, and emerging, public health and criminal justice problems hold great promise. Differential association theory postulates that close association with delinquent peers leads to an increase in deviant activities such as illicit drug use. Social cognitive theory postulates that health behavior change is driven by the interaction of (a) cognitive states that support a health outcome, (b) the social and contextual environment, (c) and individual action. Combined, these theories can be applied to drug eradication programs as well as other health and crime issues. Focus groups and interviews were performed to identify rates of illicit substance use among incarcerated African American adolescent male gang members and nongang members. The policy recommendations illustrate the convergence of criminological and epidemiological theory under the new paradigm of epidemiological criminology or ''EpiCrim.''

Sand Waves in Tidal Channels

DTIC Science & Technology

2007-01-01

sincerely thank Steven Borgeld, from Humboldt State University, for providing the grain size data for the Humboldt Entrance Channel. iv SAND...Wave Characteristics at Moriches Inlet... 182 APPENDIX VII – Sediment Data , Humboldt Entrance Channel, CA ........................... 186 References...waves may be limited by wave action, sand supply, and dredging activity. Bathymetric data collected at Humboldt Inlet, California, show sand waves

Evaluation of sand fills.

DOT National Transportation Integrated Search

1973-11-01

A popular construction technique in south Louisiana for many years has been the use of river sand to establish foundations for highways. The abundance of river sand and the need for it in excavation backfill operations across Louisiana's marshlands h...

China Dust and Sand

Atmospheric Science Data Center

2013-04-16

... article title:  Dust and Sand Sweep Over Northeast China     View Larger Image ... these views of the dust and sand that swept over northeast China on March 10, 2004. Information on the height of the dust and an ...

Spatial and seasonal responses of precipitation in the Ganges and Brahmaputra river basins to ENSO and Indian Ocean dipole modes: implications for flooding and drought

NASA Astrophysics Data System (ADS)

Pervez, M. S.; Henebry, G. M.

2014-02-01

We evaluated the spatial and temporal responses of precipitation in the basins as modulated by the El Niño Southern Oscillation (ENSO) and Indian Ocean (IO) dipole modes using observed precipitation records at 43 stations across the Ganges and Brahmaputra basins from 1982 to 2010. Daily observed precipitation records were extracted from Global Surface Summary of the Day dataset and spatial and monthly anomalies were computed. The anomalies were averaged for the years influenced by climate modes combinations. Occurrences of El Niño alone significantly reduced (60% and 88% of baseline in the Ganges and Brahmaputra basins, respectively) precipitation during the monsoon months in the northwestern and central Ganges basin and across the Brahmaputra basin. In contrast, co-occurrence of La Niña and a positive IO dipole mode significantly enhanced (135% and 160% of baseline, respectively) precipitation across both basins. During the co-occurrence of neutral phases in both climate modes (occurring 13 out of 28 yr), precipitation remained below average to average in the agriculturally extensive areas of Haryana, Uttar Pradesh, Bihar, eastern Nepal, and the Rajshahi district in Bangladesh in the Ganges basin and northern Bangladesh, Meghalaya, Assam, and Arunachal Pradesh in the Brahmaputra basin. This pattern implies that a regular water deficit is likely in these areas with implications for the agriculture sector due to its reliance on consistent rainfall for successful production. Major flooding and drought occurred as a consequence of the interactive effects of the ENSO and IO dipole modes, with the sole exception of extreme precipitation and flooding during El Niño events. This observational analysis will facilitate well informed decision making in minimizing natural hazard risks and climate impacts on agriculture, and supports development of strategies ensuring optimized use of water resources in best management practice under changing climate.

Faecal indicator bacteria enumeration in beach sand: a comparison study of extraction methods in medium to coarse sands.

PubMed

Boehm, A B; Griffith, J; McGee, C; Edge, T A; Solo-Gabriele, H M; Whitman, R; Cao, Y; Getrich, M; Jay, J A; Ferguson, D; Goodwin, K D; Lee, C M; Madison, M; Weisberg, S B

2009-11-01

The absence of standardized methods for quantifying faecal indicator bacteria (FIB) in sand hinders comparison of results across studies. The purpose of the study was to compare methods for extraction of faecal bacteria from sands and recommend a standardized extraction technique. Twenty-two methods of extracting enterococci and Escherichia coli from sand were evaluated, including multiple permutations of hand shaking, mechanical shaking, blending, sonication, number of rinses, settling time, eluant-to-sand ratio, eluant composition, prefiltration and type of decantation. Tests were performed on sands from California, Florida and Lake Michigan. Most extraction parameters did not significantly affect bacterial enumeration. anova revealed significant effects of eluant composition and blending; with both sodium metaphosphate buffer and blending producing reduced counts. The simplest extraction method that produced the highest FIB recoveries consisted of 2 min of hand shaking in phosphate-buffered saline or deionized water, a 30-s settling time, one-rinse step and a 10 : 1 eluant volume to sand weight ratio. This result was consistent across the sand compositions tested in this study but could vary for other sand types. Method standardization will improve the understanding of how sands affect surface water quality.

Early Childhood: Discovery through Sand Play.

ERIC Educational Resources Information Center

McIntyre, Margaret

1982-01-01

Suggestions are given for using sand play to teach science related vocabulary and concepts to preschool and primary age children by using dry sand, wet sand, different sizes and shapes of spoons and containers, sieves, and funnels. (DC)

Asbestos in play sand

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langer, A.M.; Nolan, R.P.

1987-04-02

A letter in the New England Journal of Medicine (Oct. 2 issue) stated that a carbonate sand marketed in New Jersey was contaminated with 2 to 4 percent tremolite asbestos. The authors were called on by one of the federal agencies to repeat the analysis of this sand, specifically for its asbestos content. The sand was pulverized and immersed in oils with known refractive indexes, and the predominant amphibole was characterized by polarized light microscopy. The optical characteristics were noted, and the indexes of refraction were measured and found to be consistent with tremolite. On the basis of optical characterization,more » the authors concluded that all the tremolite visualized with light microscopy consisted of large, single cleavage fragments and was not asbestiform. They used the technique of x-ray diffraction, as did the author of the original report, which showed the presence of an amphibole mineral (probably tremolite) in the carbonate sand. The technique was not used, and cannot be used, to distinguish between the tremolite habits (asbestiform or nonasbestiform). An acid-insoluble residue, recovered from the carbonate sand, was examined by analytic electron microscopy. The tremolite grains were observed to consist of single untwinned, crystalline fragments. Few defects were noted. Selected area electron diffraction nets were indicative of fragments lying near or at the common amphibole cleavage plane. These characteristics are consistent with cleavage fragments and not asbestos. Aspect ratios reflected short particles (less than 5.1). On the basis of their examination of the carbonate play sand, they conclude that it did not contain tremolite asbestos.« less

Comparison of buried sand ridges and regressive sand ridges on the outer shelf of the East China Sea

NASA Astrophysics Data System (ADS)

Wu, Ziyin; Jin, Xianglong; Zhou, Jieqiong; Zhao, Dineng; Shang, Jihong; Li, Shoujun; Cao, Zhenyi; Liang, Yuyang

2017-06-01

Based on multi-beam echo soundings and high-resolution single-channel seismic profiles, linear sand ridges in U14 and U2 on the East China Sea (ECS) shelf are identified and compared in detail. Linear sand ridges in U14 are buried sand ridges, which are 90 m below the seafloor. It is presumed that these buried sand ridges belong to the transgressive systems tract (TST) formed 320-200 ka ago and that their top interface is the maximal flooding surface (MFS). Linear sand ridges in U2 are regressive sand ridges. It is presumed that these buried sand ridges belong to the TST of the last glacial maximum (LGM) and that their top interface is the MFS of the LGM. Four sub-stage sand ridges of U2 are discerned from the high-resolution single-channel seismic profile and four strikes of regressive sand ridges are distinguished from the submarine topographic map based on the multi-beam echo soundings. These multi-stage and multi-strike linear sand ridges are the response of, and evidence for, the evolution of submarine topography with respect to sea-level fluctuations since the LGM. Although the difference in the age of formation between U14 and U2 is 200 ka and their sequences are 90 m apart, the general strikes of the sand ridges are similar. This indicates that the basic configuration of tidal waves on the ECS shelf has been stable for the last 200 ka. A basic evolutionary model of the strata of the ECS shelf is proposed, in which sea-level change is the controlling factor. During the sea-level change of about 100 ka, five to six strata are developed and the sand ridges develop in the TST. A similar story of the evolution of paleo-topography on the ECS shelf has been repeated during the last 300 ka.

Azimuthal Structure of the Sand Erg that Encircles the North Polar Water-Ice Cap

NASA Astrophysics Data System (ADS)

Teodoro, L. A.; Elphic, R. C.; Eke, V. R.; Feldman, W. C.; Maurice, S.; Pathare, A.

2011-12-01

The sand erg that completely encircles the perennial water-ice cap that covers the Martian north geographic pole displays considerable azimuthal structure as seen in visible and near-IR images. Much of this structure is associated with the terminations of the many steep troughs that cut spiral the approximately 3 km thick polar ice cap. Other contributions come from the katabatic winds that spill over steep-sided edges of the cap, such as what bounds the largest set of dunes that comprise Olympia Undae. During the spring and summer months when these winds initiate from the higher altitudes that contain sublimating CO2 ice, which is very cold and dry, heat adiabatically when they compress as they lose altitude. These winds should then remove H2O moisture from the uppermost layer of the sand dunes that are directly in their path. Two likely locations where this desiccation may occur preferentially is at the termination of Chasma Boreale and the ice cap at Olympia Undae. We will search for this effect by sharpening the spatial structure of the epithermal neutron counting rates measured at northern high latitudes using the Mars Odyssey Neutron Spectrometer (MONS). The epithermal range of neutron energies is nearly uniquely sensitive to the hydrogen content of surface soils, which should likely be in the form of H2O/OH molecules/radicals. We therefore convert epithermal counting rates in terms of Water-Equivalent-Hydrogen, WEH. However, MONS counting-rate data have a FWHM of ~550 km., which is sufficiently broad to prevent a close association of WEH variability with images of geological features. In this study, we reduce spurious features in the instrument smeared neutron counting rates through deconvolution. We choose the PIXON numerical deconvolution technique for this purpose. This technique uses a statistical approach (Pina 2001, Eke 2001), which is capable of removing spurious features in the data in the presence of noise. We have previously carried out a detailed

The use of Papuan iron sand and river sand for fine aggregate in mortar for nuclear radiation shield application

NASA Astrophysics Data System (ADS)

Dahlan, K.; Haryati, E.; Aninam, Y. S.

2018-03-01

This study explores the effect of fine aggregate on mortar properties and its application as a nuclear shield. This study was based on a hypothesis that the types of aggregate applied as radiation shield determined the level of its effectiveness on preventing nuclear radiation. There are two types and sources of fine aggregate that was used as main ingredients for mortar production in this research, namely iron sand and river sand. Both types of sand were derived from the respective regions of Sarmi and Jayapura, Papua. The results showed that the mortar materials that were produced with the iron sand provided better results in dispelling radiation than that of river sand. The compressive strength of fine aggregate from the iron sand was 21.62 MPa, while the compressive strength of the river sand was 16.8 MPa. Measuring the attenuation coefficient of material, we found that the largest aggregated value of mortar with fine iron sand reached 0.0863 / cm. On the other hand, the smallest HVT (Half Value Thickness) was obtained from the iron sand mortar, at 8.03 cm.

Faecal indicator bacteria enumeration in beach sand: A comparison study of extraction methods in medium to coarse sands

USGS Publications Warehouse

Boehm, A.B.; Griffith, J.; McGee, C.; Edge, T.A.; Solo-Gabriele, H. M.; Whitman, R.; Cao, Y.; Getrich, M.; Jay, J.A.; Ferguson, D.; Goodwin, K.D.; Lee, C.M.; Madison, M.; Weisberg, S.B.

2009-01-01

Aims: The absence of standardized methods for quantifying faecal indicator bacteria (FIB) in sand hinders comparison of results across studies. The purpose of the study was to compare methods for extraction of faecal bacteria from sands and recommend a standardized extraction technique. Methods and Results: Twenty-two methods of extracting enterococci and Escherichia coli from sand were evaluated, including multiple permutations of hand shaking, mechanical shaking, blending, sonication, number of rinses, settling time, eluant-to-sand ratio, eluant composition, prefiltration and type of decantation. Tests were performed on sands from California, Florida and Lake Michigan. Most extraction parameters did not significantly affect bacterial enumeration. anova revealed significant effects of eluant composition and blending; with both sodium metaphosphate buffer and blending producing reduced counts. Conclusions: The simplest extraction method that produced the highest FIB recoveries consisted of 2 min of hand shaking in phosphate-buffered saline or deionized water, a 30-s settling time, one-rinse step and a 10 : 1 eluant volume to sand weight ratio. This result was consistent across the sand compositions tested in this study but could vary for other sand types. Significance and Impact of the Study: Method standardization will improve the understanding of how sands affect surface water quality. ?? 2009 The Society for Applied Microbiology.

Sand-wave movement on Little Georges Bank

USGS Publications Warehouse

Twichell, David C.

1983-01-01

A 1-x-1.5-km area on Little Georges Bank (centered at 41?08?N., 68?04?W.) was mapped three times during a ten-month period by sidescan sonar and echo-sounding techniques to assess the morphology and mobility of sand waves on Georges Bank. Sand-wave amplitudes in the survey area ranged from 1-11 m although most were 5-7 m. Wavelengths were not constant as the crests were sinuous and in places, even bifurcated. The sand waves are asymmetrical with their steepest sides facing northwest; however, gradients of their steep sides mostly are 4?-10? which is well below the angle of repose for sand in water. Sand waves tended to have greater relief and a sharper asymmetry during the survey in September than during those in June or April. During the survey period the sand waves moved but the direction and rate of motion was variable. Even along an individual sand wave some parts moved as much as 60 m between surveys while other parts apparently remained stationary. The sand waves were asymmetrical, but movement was not consistently in the direction that the steep sides faced. Along the same sand wave, parts moved to the northwest while other parts moved to the southeast. Despite the complex pattern of sand motion, the mean displacement of the sand waves was below the resolution of the survey technique; to resolve it, a longer survey is needed.

Towards a National Gang Strategy: A Meta-Policy Analysis of Leadership, Learning, and Organizational Change within the Law Enforcement Context

ERIC Educational Resources Information Center

Richards, Maurice V.

2010-01-01

This study examines the process of change within law enforcement, focusing on the leadership, learning, and organizational change required to reduce crime, violence, and social disruption caused by criminal street gangs. The study tests the viability, results, and implications of a new policing model, the trans-jurisdictional task force, through…

METHOD OF PROCESSING MONAZITE SAND

DOEpatents

Calkins, G.D.

1957-10-29

A method is given for the pretreatment of monazite sand with sodium hydroxide. When momazite sand is reacted with sodium hydroxide, the thorium, uranium, and rare earths are converted to water-insoluble hydrous oxides; but in the case of uranium, the precipitate compound may at least partly consist of a slightly soluble uranate. According to the patent, monazite sand is treated with an excess of aqueous sodium hydroxide solution, and the insoluble compounds of thorium, uranium, and the rare earths are separated from the aqueous solution. This solution is then concentrated causing sodium phosphate to crystallize out. The crystals are removed from the remaining solution, and the solution is recycled for reaction with a mew supply of momazite sand.

Drive-by shootings by violent street gangs in Los Angeles: a five-year review from 1989 to 1993.

PubMed

Huston, H R; Anglin, D; Eckstein, M

1996-04-01

To determine trends in the numbers of drive-by shootings, individuals shot at, innocent bystanders shot at, and homicides by drive-by shootings in the city of Los Angeles from 1989 to 1993. A retrospective analysis of police records was performed for all gang-related drive-by shootings that occurred in the city of Los Angeles between 1989 and 1993. From 1989 to 1993, there were 6,327 drive-by shootings, 9,053 people shot at, and 590 homicides. There was an increase in drive-by shootings, people shot at, and homicides between 1989 and 1991, followed by a decrease between 1991 and 1993. The case fatality ratio of individuals killed to individuals shot at increased from 1989 to 1993 (p = 0.0011). Forty-seven percent of the people shot at, and 23% of the homicide victims, were innocent bystanders. Drive-by shootings are a major public health problem in Los Angeles. While the rate of drive-by shootings decreased in 1992 and 1993, the proportion of fatal cases increased. To prevent drive-by shootings, the root causes of violent street gang formation must be addressed.

A study of global sand seas

USGS Publications Warehouse

McKee, Edwin D.

1979-01-01

The birth of the idea that led to this publication on "Global Sand Seas" dates back to the late 1920's. At that time I was engaged in a study of the Coconino Sandstone of Arizona's Grand Canyon. Considerable controversy existed then as to whether this sandstone was a subaqueous deposit or was composed of wind-formed dunes. It became apparent that definitive literature was sparse or lacking on types of dunes, global distribution of these types, the mechanics of their development, the precise nature of their internal structure of cross-stratificiation, and the relation of wind systems to these sand forms. Especially lacking were data on criteria that could confidently be used in the recognition of ancient dunes. The common denominator in this publication is eolian sand bodies. Although the book is concerned primarily with desert sand seas, the subject matter is not restricted to deserts; it includes many references to deposits of coastal sand and to sand bodies in humid climates. Nor does the book deal exclusively with dunes, which, according to most definitions, involve mounds or hills. Many references are made to sand sheets, sand stringers, and other types of sand deposits that have no prominent topographic expression. All sand bodies accumulated by the action of wind are discussed. Chapters A-J of this publication are primarily topical. Chapters cover the grain texture, the color, and the structure of modern dunes and other eolian sands. Special treatment is given to the relation of wind data to dune interpretation, the evolution of form in current-deposited sand bodies as determined from experimental studies, and the discriminant analysis technique for differentiating between coastal and inland desert sands. This topical part of the publication also includes an analysis of criteria used in ancient deposits to interpret their eolian genesis and a consideration of economic application of the principles described, including a discussion of potentials and problems

Fresh Exposures of Fe-Allophane/Opal in Association with Channels and Debris Aprons in Coprates Chasma, Mars

NASA Astrophysics Data System (ADS)

Weitz, C. M.; Bishop, J. L.; Baker, L.; Berman, D. C.

2014-04-01

We have discovered relatively fresh deposits of a hydrated, amorphous material resembling Fe-rich allophane or opal along the wallrock slopes in Coprates Chasma, Mars (Fig. 1). The deposits appear similar to numerous mass wasting flows and debris aprons visible along the wallrock slopes. It is only with the aid of CRISM visible and near-infrared reflectance spectral data that these deposits appear distinct. Spectra extracted from the deposits exhibit broad absorptions at 1.42, 1.94, and ~2.25 μm. These broad absorptions and peaks shifted to longer wavelengths relative to spectra of allophane and opal are most consistent with Fe-allophane/opal produced synthetically in the laboratory. The three absorptions, especially the 1.4 μm, are very strong relative to most martian hydrated spectra, suggesting high water content that is relatively fresh and has not altered or lost water since formation/exposure. The confinement and concentration of Fe-allophane/opal into channels suggests that there was movement downslope, but the channels may have formed previously and could have been used as a conduit by the younger Fe-allophane/opal debris.

Numerical simulation of wind-sand movement in the reversed flow region of a sand dune with a bridge built downstream.

PubMed

He, Wei; Huang, Ning; Xu, Bin; Wang, Wenbo

2018-04-23

A bridge built inside the reversed flow region of a sand dune will change the characteristics of wind-sand movement in this region. The Reynolds-averaged Navier-Stokes simulation and discrete particle tracing are used to simulate the wind-sand movement around a sand dune with a bridge built inside the reversed region. Three cases with different bridge positions are studied. The results show that 1) compared with the isolated dune case, a tall bridge built at the leeward toe leads to an increase in the deposition rate on the leeward slope and a longer reversed flow region downstream of the sand dune; meanwhile, the high speed of crosswind on the bridge indicates that some measures should be taken to protect trains from strong crosswind; 2) a low bridge at the leeward toe has little effect on the sand deposition and reversed flow region of the dune; however, low sand transport rate and crosswind speed on the bridge show that anti-crosswind/sand measures should be taken according to the actual situation and 3) a low bridge on the leeward slope has little effect on the length of reversed flow region, however, high crosswind speed and sand flux on the bridge reveal the need of anti-crosswind/sand measures on the bridge. Moreover, the bridges in the reversed flow region increase the sand flux near the leeward crest; as a result, the moving patterns of the sand dune are changed.

Sand dune tracking from satellite laser altimetry

NASA Astrophysics Data System (ADS)

Dabboor, Mohammed

Substantial problems arise from sand movement in arid and semi-arid countries. Sand poses a threat to infrastructure, agricultural and urban areas. These issues are caused by the encroachment of sand on roads and railway tracks, farmland, towns and villages, and airports, to name a few. Sand movement highly depends on geomorphology including vegetation cover, shape and height of the terrain, and grain size of the sand. However, wind direction and speed are the most important factors that affect efficient sand movement. The direction of the movement depends on the main direction of the wind, but it has been shown that a minimum wind speed is required, e.g. wind gusts, to initiate sand transport. This fact prevents a simple calculation of sand transport from conventional wind data as wind records rarely contain sub-minute intervals masking out any wind gusts. An alternative of predicting sand transport is the direct observation of sand advance by in situ measurements or via satellite. Until recently, satellite imagery was the only means to compare dune shape and position for predicting dune migration over several years. In 2003, the NASA laser altimetry mission ICESat became operational and monitors elevations over all surface types including sand dunes with an accuracy of about 10-20 cm. In this study, ICESat observations from repeat tracks (tracks overlapping eachother within 50 m) are used to derive sand dune advance and direction. The method employs a correlation of the elevation profiles over several dunes and was sucessfully validated with synthetic data. The accuracy of this method is 5 meters of dune advance. One of the most active areas exhibiting sand and dune movement is the area of the Arabian Peninsula. Approximately one-third of the Arabian Peninsula is covered by sand dunes. Different wind regimes (Shamal, Kaus) cause sand dune movement in the selected study area in the eastern part of the Arabian Peninsula between 20-25 degrees North and 45-55 degrees

Lazy river on Mars: Ring-shaped fluvial channel discovered north of Capri Chasma

NASA Astrophysics Data System (ADS)

Thomson, B. J.

2017-12-01

Many features on Mars are strange, but some are stranger than others. Fluvial features on Mars come in several basic flavors: branching valley networks, massive outflow channels, and possibly presently active recurring slope lineae. Here, we identify a small, valley network-like channel segment whose planform appearance traces out a nearly complete circle. One of the key tenants of hydrogeology and plumbing is that "stuff flows downhill." A seemingly circular loop implies a gross violation of the downhill flow rule, akin to a visual claim of perpetual motion. This M.C. Escher-inspired landform is located at 6.45°S, 39.70°W inside Innsbruck crater, a 59-km diameter impact structure that is just north of Capri Chasma. A close inspection reveals that the loop is not 100% continuous; there is a slight break on the western side of the loop. The pair of channels on either side of this gap terminate abruptly. These appear to be points of origin rather than termini, although admittedly the direction(s) of flow within the channel segments are difficult to constrain uniquely. The overall morphology of this near-circular channel system implies a local source limited both in duration and volume. Assuming that the fluid involved was water, the volume of water was sufficient for incipient erosion of the terrain, but not sufficient to have ponded or continued to flow. Here, the combined infiltration and evaporation rates must have been sufficiently large such that a breakout flow did not occur.

Critical state of sand matrix soils.

PubMed

Marto, Aminaton; Tan, Choy Soon; Makhtar, Ahmad Mahir; Kung Leong, Tiong

2014-01-01

The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, λ, and Γ. The range of the value of M, λ, and Γ is 0.803-0.998, 0.144-0.248, and 1.727-2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated.

Sand Sources Near Athabasca Valles

NASA Image and Video Library

2014-10-29

This image captured by NASA Mars Reconnaissance Orbiter shows a small channel cutting into young volcanic lavas in a region where massive catastrophic flooding took place in the relatively recent past. The Athabasca Valles region includes a vast lava flow, thought to be the youngest on Mars, with even younger outflow channels that were carved by running water. The source of the water is believed to be the Cerberus Fossae valleys to the north, which may have penetrated to an over-pressurized aquifer in the subsurface. Nowadays, erosion by gravity, wind, and frost gradually wears down the rims of the outflow channels. In this scene, we see dark materials along the channel rim that were probably exposed by this erosion. The dark materials are less red than the surrounding surface and so they appear blue in this enhanced color picture. Viewed close up, the dark materials show ripples that suggest they are made up of mobile sand. It is possible that this sand originated elsewhere and simply collected where we see it today, but the fact that sand is not found elsewhere in the scene suggest to us that it is eroding out of the volcanic layers at the retreating rim of the channel. Sand sources are important because mobile sand grains have only a limited lifetime, wearing down and chipping apart each time they impact the surface. Erosion of the volcanic materials in this region may provide sands to replace those that are destroyed. Few such sand sources have so far been identified on Mars. http://photojournal.jpl.nasa.gov/catalog/PIA18889

Earth-like sand fluxes on Mars.

PubMed

Bridges, N T; Ayoub, F; Avouac, J-P; Leprince, S; Lucas, A; Mattson, S

2012-05-09

Strong and sustained winds on Mars have been considered rare, on the basis of surface meteorology measurements and global circulation models, raising the question of whether the abundant dunes and evidence for wind erosion seen on the planet are a current process. Recent studies showed sand activity, but could not determine whether entire dunes were moving--implying large sand fluxes--or whether more localized and surficial changes had occurred. Here we present measurements of the migration rate of sand ripples and dune lee fronts at the Nili Patera dune field. We show that the dunes are near steady state, with their entire volumes composed of mobile sand. The dunes have unexpectedly high sand fluxes, similar, for example, to those in Victoria Valley, Antarctica, implying that rates of landscape modification on Mars and Earth are similar.

Chryse Outflow Channel

NASA Image and Video Library

1998-06-08

A color image of the south Chryse basin Valles Marineris outflow channels on Mars; north toward top. The scene shows on the southwest corner the chaotic terrain of the east part of Valles Marineris and two of its related canyons: Eos and Capri Chasmata (south to north). Ganges Chasma lies directly north. The chaos in the southern part of the image gives rise to several outflow channels, Shalbatana, Simud, Tiu, and Ares Valles (left to right), that drained north into the Chryse basin. The mouth of Ares Valles is the site of the Mars Pathfinder lander. This image is a composite of NASA's Viking medium-resolution images in black and white and low-resolution images in color. The image extends from latitude 20 degrees S. to 20 degrees N. and from longitude 15 degrees to 53 degrees; Mercator projection. http://photojournal.jpl.nasa.gov/catalog/PIA00418

Modeling surficial sand and gravel deposits

USGS Publications Warehouse

Bliss, J.D.; Page, N.J.

1994-01-01

Mineral-deposit models are an integral part of quantitative mineral-resource assessment. As the focus of mineral-deposit modeling has moved from metals to industrial minerals, procedure has been modified and may be sufficient to model surficial sand and gravel deposits. Sand and gravel models are needed to assess resource-supply analyses for planning future development and renewal of infrastructure. Successful modeling of sand and gravel deposits must address (1) deposit volumes and geometries, (2) sizes of fragments within the deposits, (3) physical characteristics of the material, and (4) chemical composition and chemical reactivity of the material. Several models of sand and gravel volumes and geometries have been prepared and suggest the following: Sand and gravel deposits in alluvial fans have a median volume of 35 million m3. Deposits in all other geologic settings have a median volume of 5.4 million m3, a median area of 120 ha, and a median thickness of 4 m. The area of a sand and gravel deposit can be predicted from volume using a regression model (log [area (ha)] =1.47+0.79 log [volume (million m3)]). In similar fashion, the volume of a sand and gravel deposit can be predicted from area using the regression (log [volume (million m3)]=-1.45+1.07 log [area (ha)]). Classifying deposits by fragment size can be done using models of the percentage of sand, gravel, and silt within deposits. A classification scheme based on fragment size is sufficiently general to be applied anywhere. ?? 1994 Oxford University Press.

Ocean Sand, Bahamas

NASA Image and Video Library

2011-04-20

NASA image acquired January 17, 2001 Though the above image may resemble a new age painting straight out of an art gallery in Venice Beach, California, it is in fact a satellite image of the sands and seaweed in the Bahamas. The image was taken by the Enhanced Thematic Mapper plus (ETM+) instrument aboard the Landsat 7 satellite. Tides and ocean currents in the Bahamas sculpted the sand and seaweed beds into these multicolored, fluted patterns in much the same way that winds sculpted the vast sand dunes in the Sahara Desert. Image courtesy Serge Andrefouet, University of South Florida Instrument: Landsat 7 - ETM+ Credit: NASA/GSFC/Landsat NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Join us on Facebook

Drought Characteristics Based on the Retrieved Paleoprecipitation in Indus and Ganges River Basins

NASA Astrophysics Data System (ADS)

Davtalabsabet, R.; Wang, D.; Zhu, T.; Ringler, C.

2014-12-01

Indus and Ganges River basins (IGRB), which cover the major parts of India, Nepal, Bangladesh and Pakistan, are considered as the most important socio-economic regions in South Asia. IGRB support the food security of hundreds of millions people in South Asia. The food production in IGRB strictly relies on the magnitude and spatiotemporal pattern of monsoon precipitation. Due to severe drought during the last decades and food production failure in IGRB, several studies have focused on understanding the main drivers for south Asia monsoon failures and drought characteristics based on the historical data. However, the period of available historical data is not enough to address the full characteristic of drought under a changing climate. In this study, an inverse Palmer Drought Severity Index (PDSI) model is developed to retrieve the paleoprecipitation back to 700 years in the region, taking the inputs of available soil water capacity, temperature, and previous reconstructed PDSI based on tree-ring analysis at 2.5 degree resolution. Based on the retrieved paleoprecipitation, drought frequency and intensity are quantified for two periods of 1300-1899 (the reconstruction period) and 1900-2010 (the instrumental period). Previous studies have shown that in IGRB, a severe drought occurs when the annual precipitation deficit, compared with the long-term average precipitation, is greater than 10%. Climatic drought frequency is calculated as the percentage of years with predefined severe droughts. Drought intensity is defined as the average precipitation deficit during all of the years identified as severe droughts. Results show that the drought frequency, as well as the spatial extent, has significantly increased from the reconstruction period to the instrumental period. The drought frequency in the Indus River basin is higher than that in the Ganges River basin. Several mega-droughts are identified during the reconstruction period.

Hydroclimatic sustainability assessment of changing climate on cholera in the Ganges-Brahmaputra basin

NASA Astrophysics Data System (ADS)

Nasr-Azadani, Fariborz; Khan, Rakibul; Rahimikollu, Javad; Unnikrishnan, Avinash; Akanda, Ali; Alam, Munirul; Huq, Anwar; Jutla, Antarpreet; Colwell, Rita

2017-10-01

The association of cholera and climate has been extensively documented. However, determining the effects of changing climate on the occurrence of disease remains a challenge. Bimodal peaks of cholera in Bengal Delta are hypothesized to be linked to asymmetric flow of the Ganges and Brahmaputra rivers. Spring cholera is related to intrusion of bacteria-laden coastal seawater during low flow seasons, while autumn cholera results from cross-contamination of water resources when high flows in the rivers cause massive inundation. Coarse resolution of General Circulation Model (GCM) output (usually at 100 - 300 km)cannot be used to evaluate variability at the local scale(10-20 km),hence the goal of this study was to develop a framework that could be used to understand impacts of climate change on occurrence of cholera. Instead of a traditional approach of downscaling precipitation, streamflow of the two rivers was directly linked to GCM outputs, achieving reasonable accuracy (R2 = 0.89 for the Ganges and R2 = 0.91 for the Brahmaputra)using machine learning algorithms (Support Vector Regression-Particle Swarm Optimization). Copula methods were used to determine probabilistic risks of cholera under several discharge conditions. Key results, using model outputs from ECHAM5, GFDL, andHadCM3for A1B and A2 scenarios, suggest that the combined low flow of the two rivers may increase in the future, with high flows increasing for first half of this century, decreasing thereafter. Spring and autumn cholera, assuming societal conditions remain constant e.g., at the current rate, may decrease. However significant shifts were noted in the magnitude of river discharge suggesting that cholera dynamics of the delta may well demonstrate an uncertain predictable pattern of occurrence over the next century.

Critical State of Sand Matrix Soils

PubMed Central

Marto, Aminaton; Tan, Choy Soon; Makhtar, Ahmad Mahir; Kung Leong, Tiong

2014-01-01

The Critical State Soil Mechanic (CSSM) is a globally recognised framework while the critical states for sand and clay are both well established. Nevertheless, the development of the critical state of sand matrix soils is lacking. This paper discusses the development of critical state lines and corresponding critical state parameters for the investigated material, sand matrix soils using sand-kaolin mixtures. The output of this paper can be used as an interpretation framework for the research on liquefaction susceptibility of sand matrix soils in the future. The strain controlled triaxial test apparatus was used to provide the monotonic loading onto the reconstituted soil specimens. All tested soils were subjected to isotropic consolidation and sheared under undrained condition until critical state was ascertain. Based on the results of 32 test specimens, the critical state lines for eight different sand matrix soils were developed together with the corresponding values of critical state parameters, M, λ, and Γ. The range of the value of M, λ, and Γ is 0.803–0.998, 0.144–0.248, and 1.727–2.279, respectively. These values are comparable to the critical state parameters of river sand and kaolin clay. However, the relationship between fines percentages and these critical state parameters is too scattered to be correlated. PMID:24757417

High temperature thermal energy storage in moving sand

NASA Technical Reports Server (NTRS)

Turner, R. H.; Awaya, H. I.

1978-01-01

Several high-temperature (to 500 C) heat-storage systems using sand as the storage medium are described. The advantages of sand as a storage medium include low cost for sand, widespread availability, non-toxicity, non-degradation characteristics, easy containment, and safety. The systems considered include: stationary sand with closely spaced tubes throughout the volume, the use of a fluidized bed, use of conveyor belt transporter, and the use of a blower rapid transport system. For a stationary sand bed, very close spacing of heat transfer tubes throughout the volume is required, manifesting as high power related system cost. The suggestion of moving sand past or around pipes is intended to reduce the power related costs at the penalty of added system complexity. Preliminary system cost estimates are offered. These rough calculations indicate that mobile sand heat storage systems cost less than the stationary sand approach.

Load capacity, failure mode and design criteria investigation of sand jacks : full scale load testing of sand jacks.

DOT National Transportation Integrated Search

2008-12-01

A sand-jack is a sand filled container used as a component of cast-in-place bridge false-work. The sand filler facilitates the removal of the false-work by allowing slow and controlled lowering of the bracing that has become wedged beneath the new br...

Simple stochastic cellular automaton model for starved beds and implications about formation of sand topographic features in terms of sand flux

NASA Astrophysics Data System (ADS)

Endo, Noritaka

2016-12-01

A simple stochastic cellular automaton model is proposed for simulating bedload transport, especially for cases with a low transport rate and where available sediments are very sparse on substrates in a subaqueous system. Numerical simulations show that the bed type changes from sheet flow through sand patches to ripples as the amount of sand increases; this is consistent with observations in flume experiments and in the field. Without changes in external conditions, the sand flux calculated for a given amount of sand decreases over time as bedforms develop from a flat bed. This appears to be inconsistent with the general understanding that sand flux remains unchanged under the constant-fluid condition, but it is consistent with the previous experimental data. For areas of low sand abundance, the sand flux versus sand amount (flux-density relation) in the simulation shows a single peak with an abrupt decrease, followed by a long tail; this is very similar to the flux-density relation seen in automobile traffic flow. This pattern (the relation between segments of the curve and the corresponding bed states) suggests that sand sheets, sand patches, and sand ripples correspond respectively to the free-flow phase, congested phase, and jam phase of traffic flows. This implies that sand topographic features on starved beds are determined by the degree of interference between sand particles. Although the present study deals with simple cases only, this can provide a simplified but effective modeling of the more complicated sediment transport processes controlled by interference due to contact between grains, such as the pulsatory migration of grain-size bimodal mixtures with repetition of clustering and scattering.

Cytotoxicity of yellow sand in lung epithelial cells.

PubMed

Kim, Y H; Kim, K S; Kwak, N J; Lee, K H; Kweon, S A; Lim, Y

2003-02-01

The present study was carried out to observe the cytotoxicity of yellow sand in comparison with silica and titanium dioxide in a rat alveolar type II cell line (RLE-6TN). Yellow sand (China Loess) was obtained from the loess layer in the Gunsu Province of China. The mean particle diameter of yellow sand was about 0.003 +/- 0.001 mm. Major elements of yellow sand were Si(27.7 +/- 0.6%), Al(6.01 +/- 0.17%), and Ca(5.83 +/- 0.23%) in that order. Silica and yellow sand significantly decreased cell viability and increased [Ca2+]i. All three particles increased the generation of H2O2. TiO2 did not change Fenton activity, while silica induced a slight increase of Fenton activity. In contrast, yellow sand induced a significant increase of Fenton activity. Silica, yellow sand and TiO2 induced significant nitrite formations in RLE-6TN cells. Silica showed the highest increase in nitrite formation, while yellow sand induced the least formation of nitrite. Silica and yellow sand increased the release of TNF-a. Based on these results, we suggest that yellow sand can induce cytotoxicity in RLE-6TN cells and reactive oxygen species, Fenton activity and reactive nitrogen species might be involved in this toxicity.

Analysis of an evaporitic dome in eastern Tithonium Chasma (Mars): the result of diapirism processes?

NASA Astrophysics Data System (ADS)

Davide, Baioni; Forese Carlo, Wezel

2010-05-01

The Tithonium Chasma (TC) is the northern trench of the western troughs of Valles Marineris (Mars). In the easternmost part of the canyon system a mountain displaying dome shape morphology is located. The mineralogical characteristics of the dome have been indicated by the OMEGA image spectrometer data that mapped it as a sulphate deposit (OMEGA data orbit 531_3). Studies on the spectral characteristic absorptions for the hydrated magnesium sulphates carried out on the deposits within the Tithonium Chasma, showed the mineralogical components displayed by the dome in detail. According to these results the dome shows clear signatures of kieserite (Mg SO4.H2O), an evaporitic mineral also found on the Earth. Further studies carried out on the characteristics and the genesis of Kieserite both on Mars and on the Earth showed that the dome can not be constituted entirely by kieserite alone but probably it might be constituted also by the same salts that on the Earth alter to kieserite, such as, carnallite, kainite and halite. In this work we investigated in great detail the surface features of the dome located in the eastern part of TC, with the aim to try to determine its nature and origin. The morphological features of the dome have been investigated through the integrate analysis of HiRISE, HRSC, MOC and THEMIS data, while the morphometric characteristics have been measured on a topographic map (50 m contours lines) built using HRSC and MOLA data. The observation of the dome surface highlights features created by fluvio-erosional and solutional processes. The dome appears to be characterized by deep gully morphology displaying a radial system that develops from the margins of the summit plateau. The solutional surface is characterized by landforms typical of the karst morphology such as, karren, dolines and collapse dolines. Depositional forms displaying periglacial rock glacier features can be seen at the foot of the slopes, while they seem to be lacking along the

Analysis of wind-blown sand movement over transverse dunes.

PubMed

Jiang, Hong; Huang, Ning; Zhu, Yuanjian

2014-12-01

Wind-blown sand movement often occurs in a very complicated desert environment where sand dunes and ripples are the basic forms. However, most current studies on the theoretic and numerical models of wind-blown sand movement only consider ideal conditions such as steady wind velocity, flat sand surface, etc. In fact, the windward slope gradient plays a great role in the lift-off and sand particle saltation. In this paper, we propose a numerical model for the coupling effect between wind flow and saltating sand particles to simulate wind-blown sand movement over the slope surface and use the SIMPLE algorithm to calculate wind flow and simulate sands transport by tracking sand particle trajectories. We furthermore compare the result of numerical simulation with wind tunnel experiments. These results prove that sand particles have obvious effect on wind flow, especially that over the leeward slope. This study is a preliminary study on windblown sand movement in a complex terrain, and is of significance in the control of dust storms and land desertification.

Analysis of Wind-blown Sand Movement over Transverse Dunes

PubMed Central

Jiang, Hong; Huang, Ning; Zhu, Yuanjian

2014-01-01

Wind-blown sand movement often occurs in a very complicated desert environment where sand dunes and ripples are the basic forms. However, most current studies on the theoretic and numerical models of wind-blown sand movement only consider ideal conditions such as steady wind velocity, flat sand surface, etc. In fact, the windward slope gradient plays a great role in the lift-off and sand particle saltation. In this paper, we propose a numerical model for the coupling effect between wind flow and saltating sand particles to simulate wind-blown sand movement over the slope surface and use the SIMPLE algorithm to calculate wind flow and simulate sands transport by tracking sand particle trajectories. We furthermore compare the result of numerical simulation with wind tunnel experiments. These results prove that sand particles have obvious effect on wind flow, especially that over the leeward slope. This study is a preliminary study on windblown sand movement in a complex terrain, and is of significance in the control of dust storms and land desertification. PMID:25434372

Influence of a Reclaimed Sand Addition to Moulding Sand with Furan Resin on Its Impact on the Environment.

PubMed

Holtzer, Mariusz; Dańko, Rafał; Kmita, Angelika

Metalcasting involves having a molten metal poured in a hollow mould to produce metal objects. These moulds are generally made of sand and are chemically bonded, clay-bonded, or even unbounded. There are many binder systems used. Binders based on furfuryl resins constitute currently the highest fraction in the binders no-bake group. Moulding sand, after knocking out the cast, is partially reclaimed, and the remaining part, known as waste foundry sand is used or stored outside the foundry. In this case, the environment hazardous organic compounds and metals can be leached from the moulding sand, thus causing pollution of water and soil. Also during the casting moulds with molten metal, they emit pyrolysis gases containing many different compounds, often dangerous from the BTEX and PAH group, which has adverse impacts on the environment and workers. The article presents the results of research on the impact of the regenerate addition to the moulding sand matrix on emitted gases and the degree of threat to the environment due to leaching of hazardous components. Therefore, for the total assessment of the moulding sands harmfulness, it is necessary to perform investigations concerning the dangerous substances elution into the environment during their management and storage, as well as investigations concerning emissions of hazardous substances (especially from the BTEX and PAHs group) during moulds pouring, cooling, and casting knocking out. Both kinds of investigations indicated that reclaimed sand additions to moulding sands have significantly negative influence on the environment and working conditions.

Northern Sand Sea

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site]

Our topic for the weeks of April 4 and April 11 is dunes on Mars. We will look at the north polar sand sea and at isolated dune fields at lower latitudes. Sand seas on Earth are often called 'ergs,' an Arabic name for dune field. A sand sea differs from a dune field in two ways: 1) a sand sea has a large regional extent, and 2) the individual dunes are large in size and complex in form.

This VIS image was taken at 82 degrees North latitude during Northern spring. The image is completely dominated by dunes. In sand seas, it is very common for a single type of dune to occur, and for a single predominate wind to control the alignment of the dunes.

Image information: VIS instrument. Latitude 82.2, Longitude 152.5 East (207.5 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Sands at Gusev Crater, Mars

NASA Astrophysics Data System (ADS)

Cabrol, Nathalie A.; Herkenhoff, Kenneth; Knoll, Andrew H.; Farmer, Jack; Arvidson, Raymond; Grin, Edmond; Li, Ronxing; Fenton, Lori; Cohen, Barbara; Bell, James F.; Aileen Yingst, R.

2014-05-01

Processes, environments, and the energy associated with the transport and deposition of sand at Gusev Crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions. Bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the Spirit rover as it crossed the plains and went into the Columbia Hills. Fine-to-medium sand is ubiquitous in ripples and wind drifts. Most distributions show excess fine material, consistent with a predominance of wind erosion over the last 3.8 billion years. Negative skewness at West Valley is explained by the removal of fine sand during active erosion, or alternatively, by excess accumulation of coarse sand from a local source. The coarse to very coarse sand particles of ripple armors in the basaltic plains have a unique combination of size and shape. Their distribution display significant changes in their statistical moments within the ~400 m that separate the Columbia Memorial Station from Bonneville Crater. Results are consistent with aeolian and/or impact deposition, while the elongated and rounded shape of the grains forming the ripples, as well as their direction of origin, could point to Ma'adim Vallis as a possible source. For smaller particles on the traverse, our findings confirm that aeolian processes have dominated over impact and other processes to produce sands with the observed size and shape patterns across a spectrum of geologic (e.g., ripples and plains soils) and aerographic settings (e.g., wind shadows).

Sands at Gusev Crater, Mars

USGS Publications Warehouse

Cabrol, Nathalie A.; Herkenhoff, Kenneth E.; Knoll, Andrew H.; Farmer, Jack D.; Arvidson, Raymond E.; Grin, E.A.; Li, Ron; Fenton, Lori; Cohen, B.; Bell, J.F.; Yingst, R. Aileen

2014-01-01

Processes, environments, and the energy associated with the transport and deposition of sand at Gusev Crater are characterized at the microscopic scale through the comparison of statistical moments for particle size and shape distributions. Bivariate and factor analyses define distinct textural groups at 51 sites along the traverse completed by the Spirit rover as it crossed the plains and went into the Columbia Hills. Fine-to-medium sand is ubiquitous in ripples and wind drifts. Most distributions show excess fine material, consistent with a predominance of wind erosion over the last 3.8 billion years. Negative skewness at West Valley is explained by the removal of fine sand during active erosion, or alternatively, by excess accumulation of coarse sand from a local source. The coarse to very coarse sand particles of ripple armors in the basaltic plains have a unique combination of size and shape. Their distribution display significant changes in their statistical moments within the ~400 m that separate the Columbia Memorial Station from Bonneville Crater. Results are consistent with aeolian and/or impact deposition, while the elongated and rounded shape of the grains forming the ripples, as well as their direction of origin, could point to Ma'adim Vallis as a possible source. For smaller particles on the traverse, our findings confirm that aeolian processes have dominated over impact and other processes to produce sands with the observed size and shape patterns across a spectrum of geologic (e.g., ripples and plains soils) and aerographic settings (e.g., wind shadows).

Mineral resource of the month: industrial sand and gravel

USGS Publications Warehouse

Dolley, Thomas

2007-01-01

With many diverse uses, industrial sand and gravel, also known as silica sand, is one of the most important nonmetallic minerals in the world. Industrial sand and gravel is a mining industry term used for sands that have a very high percentage of silicon dioxide, or greater than 95 percent quartz. Deposits of industrial sand and gravel can be found virtually everywhere on Earth, but are less widespread than deposits of common construction sand and gravel. Industrial sand and gravel is distinctive in grain size, hardness, inertness and resistance to high temperature and chemical action. Beverage containers, fiberglass insulation, fiber-optic cables and light bulbs are just some of today’s many products produced from industrial sand and gravel.

Projections of the Ganges-Brahmaputra precipitation: downscaled from GCM predictors

USGS Publications Warehouse

Pervez, Md Shahriar; Henebry, Geoffrey M.

2014-01-01

Downscaling Global Climate Model (GCM) projections of future climate is critical for impact studies. Downscaling enables use of GCM experiments for regional scale impact studies by generating regionally specific forecasts connecting global scale predictions and regional scale dynamics. We employed the Statistical Downscaling Model (SDSM) to downscale 21st century precipitation for two data-sparse hydrologically challenging river basins in South Asia—the Ganges and the Brahmaputra. We used CGCM3.1 by Canadian Center for Climate Modeling and Analysis version 3.1 predictors in downscaling the precipitation. Downscaling was performed on the basis of established relationships between historical Global Summary of Day observed precipitation records from 43 stations and National Center for Environmental Prediction re-analysis large scale atmospheric predictors. Although the selection of predictors was challenging during the set-up of SDSM, they were found to be indicative of important physical forcings in the basins. The precipitation of both basins was largely influenced by geopotential height: the Ganges precipitation was modulated by the U component of the wind and specific humidity at 500 and 1000 h Pa pressure levels; whereas, the Brahmaputra precipitation was modulated by the V component of the wind at 850 and 1000 h Pa pressure levels. The evaluation of the SDSM performance indicated that model accuracy for reproducing precipitation at the monthly scale was acceptable, but at the daily scale the model inadequately simulated some daily extreme precipitation events. Therefore, while the downscaled precipitation may not be the suitable input to analyze future extreme flooding or drought events, it could be adequate for analysis of future freshwater availability. Analysis of the CGCM3.1 downscaled precipitation projection with respect to observed precipitation reveals that the precipitation regime in each basin may be significantly impacted by climate change

Predicting Gang Fight Participation in a General Youth Sample via the HEW Youth Development Model's Community Program Impact Scales, Age, and Sex.

ERIC Educational Resources Information Center

Truckenmiller, James L.

The accurate prediction of violence has been in the spotlight of critical concern in recent years. To investigate the relative predictive power of peer pressure, youth perceived negative labeling, youth perceived access to educational and occupational roles, social alienation, self-esteem, sex, and age with regard to gang fight participation…

Full scale load testing of sand-jacks.

DOT National Transportation Integrated Search

2006-06-01

A sand-jack is a sand filled container used as a component of cast-in-place bridge false-work. The sand filler facilitates the removal of the false-work by allowing slow and controlled lowering of the bracing that has become wedged beneath the new br...

Study on sand particles creep model and open pit mine landslide mechanism caused by sand fatigue liquefaction

NASA Astrophysics Data System (ADS)

Du, Dong-Ning; Wang, Lai-Gui; Zhang, Xiang-Dong; Zhang, Shu-Kun

2017-06-01

The sand particles in the sand - rock composite slope of the open pit mine occurs creep deformation and fatigue liquefaction under the action of vehicle load vibration and hydraulic gradient, which causes landslide geological disasters and it destroys the surface environment. To reveal the mechanism, a mechanics model based on the model considering the soil structural change with a new “plastic hinge” element is developed, to improve its constitutive and creep curve equations. Data from sand creep experiments are used to identify the parameters in the model and to validate the model. The results show that the mechanical model can describe the rotation progress between the sand particles, disclose the negative acceleration creep deformation stage during the third phase, and require fewer parameters while maintaining accuracy. It provides a new creep model considering rotation to analyze sand creep mechanism, which provides a theoretical basis for revealing the open pit mine landslide mechanism induced by creep deformation and fatigue liquefaction of sandy soil.

Use of sand wave habitats by silver hake

USGS Publications Warehouse

Auster, P.J.; Lindholm, J.; Schaub, S.; Funnell, G.; Kaufman, L.S.; Valentine, P.C.

2003-01-01

Silver hake Merluccius bilinearis are common members of fish communities in sand wave habitats on Georges Bank and on Stellwagen Bank in the Gulf of Maine. Observations of fish size v. sand wave period showed that silver hake are not randomly distributed within sand wave landscapes. Regression analyses showed a significant positive relationship between sand wave period and fish length. Correlation coefficients, however, were low, suggesting other interactions with sand wave morphology, the range of current velocities, and available prey may also influence their distribution. Direct contact with sand wave habitats varied over diel periods, with more fish resting on the seafloor during daytime than at night. Social foraging, in the form of polarized groups of fish swimming in linear formations during crepuscular and daytime periods, was also observed. Sand wave habitats may provide shelter from current flows and mediate fish-prey interactions. ?? 2003 The Fisheries Society of the British Isles.

Blending foundry sands with soil: Effect on dehydrogenase activity.

PubMed

Dungan, Robert S; Kukier, Urzsula; Lee, Brad

2006-03-15

Each year U.S. foundries landfill several million tons of sand that can no longer be used to make metalcasting molds and cores. A possible use for these materials is as an ingredient in manufactured soils; however, potentially harmful metals and resin binders (used to make cores) may adversely impact the soil microbial community. In this study, the dehydrogenase activity (DHA) of soil amended with molding sand (clay-coated sand known as "green sand") or core sands at 10%, 30%, and 50% (dry wt.) was determined. The green sands were obtained from iron, aluminum, and brass foundries; the core sands were made with phenol-formaldehyde or furfuryl alcohol based resins. Overall, incremental additions of these sands resulted in a decrease in the DHA which lasted throughout the 12-week experimental period. A brass green sand, which contained high concentrations of Cu, Pb, and Zn, severely impacted the DHA. By week 12 no DHA was detected in the 30% and 50% treatments. In contrast, the DHA in soil amended with an aluminum green sand was 2.1 times higher (all blending ratios), on average, at week 4 and 1.4 times greater (30% and 50% treatments only) than the controls by week 12. In core sand-amended soil, the DHA results were similar to soils amended with aluminum and iron green sands. Increased activity in some treatments may be a result of the soil microorganisms utilizing the core resins as a carbon source. The DHA assay is a sensitive indicator of environmental stress caused by foundry sand constituents and may be useful to assess which foundry sands are suitable for beneficial use in the environment.

Complexity confers stability: Climate variability, vegetation response and sand transport on longitudinal sand dunes in Australia's deserts

NASA Astrophysics Data System (ADS)

Hesse, Paul P.; Telfer, Matt W.; Farebrother, Will

2017-04-01

The relationship between antecedent precipitation, vegetation cover and sand movement on sand dunes in the Simpson and Strzelecki Deserts was investigated by repeated (up to four) surveys of dune crest plots (≈25 × 25 m) over a drought cycle (2002-2012) in both winter (low wind) and spring (high wind). Vegetation varied dramatically between surveys on vegetated and active dune crests. Indices of sand movement had significant correlations with vegetation cover: the depth of loose sand has a strong inverse relationship with crust (cyanobacterial and/or physical) while the area covered by ripples has a strong inverse relationship with the areal cover of vascular plants. However, the relationship between antecedent rainfall and vegetation cover was found to be complex. We tentatively identify two thresholds; (1) >10 mm of rainfall in the preceding 90 days leads to rapid and near total cover of crust and/or small plants <50 cm tall, and (2) >400 mm of rainfall in the preceding three years leads to higher cover of persistent and longer-lived plants >50 cm tall. These thresholds were used to predict days of low vegetation cover on dune crests. The combination of seasonality of predicted bare-crest days, potential sand drift and resultant sand drift direction explains observed patterns of sand drift on these dunes. The complex vegetation and highly variable rainfall regime confer meta-stability on the dunes through the range of responses to different intervals of antecedent rainfall and non-linear growth responses. This suggests that the geomorphic response of dunes to climate variation is complex and non-linear.

Sand wave fields beneath the Loop Current, Gulf of Mexico: Reworking of fan sands

USGS Publications Warehouse

Kenyon, Neil H.; Akhmetzhanov, A.M.; Twichell, D.C.

2002-01-01

Extensive fields of large barchan-like sand waves and longitudinal sand ribbons have been mapped by deep-towed SeaMARC IA sidescan sonar on part of the middle and lower Mississippi Fan that lies in about 3200 m of water. The area is beneath the strongly flowing Loop Current. The bedforms have not been adequately sampled but probably consist of winnowed siliciclastic-foraminiferal sands. The size (about 200 m from wingtip to wingtip) and shape of the large barchans is consistent with a previously observed peak current speed of 30 cm/s, measured 25 m above the seabed. The types of small-scale bedforms and the scoured surfaces of chemical crusts, seen on nearby bottom photographs, indicate that near-bed currents in excess of 30 cm/s may sometimes occur. At the time of the survey the sand transport direction was to the northwest, in the opposite direction to the Loop Current but consistent with there being a deep boundary current along the foot of the Florida Escarpment. Some reworking of the underlying sandy turbidites and debris flow deposits is apparent on the sidescan sonar records. Reworking by deep-sea currents, resulting in erosion and in deposits characterised by coarsening upwards structures and cross-bedding, is a process that has been proposed for sand found in cores in shallower parts of the Gulf of Mexico. This process is more widespread than hitherto supposed. 

Experimental study of optimal self compacting concrete with spent foundry sand as partial replacement for M-sand using Taguchi approach

NASA Astrophysics Data System (ADS)

Nirmala, D. B.; Raviraj, S.

2016-06-01

This paper presents the application of Taguchi approach to obtain optimal mix proportion for Self Compacting Concrete (SCC) containing spent foundry sand and M-sand. Spent foundry sand is used as a partial replacement for M-sand. The SCC mix has seven control factors namely, Coarse aggregate, M-sand with Spent Foundry sand, Cement, Fly ash, Water, Super plasticizer and Viscosity modifying agent. Modified Nan Su method is used to proportion the initial SCC mix. L18 (21×37) Orthogonal Arrays (OA) with the seven control factors having 3 levels is used in Taguchi approach which resulted in 18 SCC mix proportions. All mixtures are extensively tested both in fresh and hardened states to verify whether they meet the practical and technical requirements of SCC. The quality characteristics considering "Nominal the better" situation is applied to the test results to arrive at the optimal SCC mix proportion. Test results indicate that the optimal mix satisfies the requirements of fresh and hardened properties of SCC. The study reveals the feasibility of using spent foundry sand as a partial replacement of M-sand in SCC and also that Taguchi method is a reliable tool to arrive at optimal mix proportion of SCC.

Murzuk Sand Sea, Sahara Desert, Libya, Africa

NASA Image and Video Library

1993-01-19

STS054-152-189 (13-19 Jan. 1993) --- This near-vertical color photograph shows the very diverse landscape that is part of the great Sahara Desert of north Africa. Specifically, the vast expanse of sand dunes, located in the extreme southwestern corner of Libya, is known as the Murzuk Sand Sea. Close inspection of this photograph shows the agricultural village of Murzuk as evidenced by the numerous center pivot irrigation patterns at the edge of the Murzuk Sand Sea. The very rugged, dissected terrain to the west of this sand sea is the eastern tip of the Tassili N'ajjer Mountains and the Tadrart Plateau that are in neighboring Algeria. Several smaller areas of sand dunes are interspersed between the major areas of rock outcrops. The photograph was taken with a Linhof camera.

Invasive plants on disturbed Korean sand dunes

NASA Astrophysics Data System (ADS)

Kim, Kee Dae

2005-01-01

The sand dunes in coastal regions of South Korea are important ecosystems because of their small size, the rare species found in this habitat, and the beautiful landscapes they create. This study investigated the current vegetative status of sand dunes on three representative coasts of the Korean peninsula, and on the coasts of Cheju Island, and assessed the conditions caused by invasive plants. The relationships between the degree of invasion and 14 environmental variables were studied. Plots of sand dunes along line transects perpendicular to the coastal lines were established to estimate vegetative species coverage. TWINSPAN (Two-Way Indicator Species Analysis), CCA (Canonical Correspondence Analysis), and DCCA (Detrended Canonical Correspondence Analysis) were performed to classify communities on sand dunes and assess species composition variation. Carex kobomugi, Elymus mollis, and Vitex rotundifolia were found to be the dominant species plotted on the east, the west, and the peripheral coasts of Cheju Island, respectively. Vegetation on the south coast was totally extinct. The 19 communities, including representative C. kobomugi, C. kobomugi- Ixeris repens, C. kobomugi- Oenothera biennis, E. mollis, Lolium multiflorum- Calystegia soldanella, and V. rotundifolia- C. kobomugi, were all classified according to TWINSPAN. Oenothera biennis and L. multiflorum were exotics observed within these native communities. CCA showed that invasive native and exotic species distribution was segregated significantly, according to disturbance level, exotic species number, gravel, sand and silt contents, as well as vegetation size. It further revealed that human disturbance can strongly favor the settlement of invasive and exotic species. Restoration options to reduce exotic plants in the South Korean sand dune areas were found to be the introduction of native plant species from one sand dune into other sand dune areas, prohibition of building and the introduction of exotic

Characteristics of SCC with Fly Ash and Manufactured Sand

NASA Astrophysics Data System (ADS)

Praveen Kumar, K.; Radhakrishna

2016-09-01

Self compacting concrete (SCC) of M40 grade was designed. The binder in SCC consists of OPC and fly ash in the ratio of 65:35. River sand was replaced by manufactured sand (M-sand) at replacement levels of 20,40,60,80 and 100%. An attempt was made to evaluate the workability and strength characteristics of self compacting concrete with river sand and manufactured sand as fine aggregates. For each replacement level, constant workability was maintained by varying the dosage of superplasticizer. T50 flow time, V Funnel time, V-funnel T5 time as well as compressive, split tensile and flexural strength of SCC were found at each replacement level of M-sand. They were compared to SCC with river sand. Results indicate favourable use of M-sand in preparation of Self Compacting Concrete.

Science Learning in the Sand.

ERIC Educational Resources Information Center

Sexton, Ursula

1997-01-01

Presents activities that allow students to think about the Earth in a contextual manner and become familiar with constructive and destructive processes as they relate to sand - its origins, cyclical processes, and yielding of new products. Explores the bigger idea with a developmentally appropriate study of water, rocks, sand, physical phenomena,…

Documenting the global impacts of beach sand mining

NASA Astrophysics Data System (ADS)

Young, R.; Griffith, A.

2009-04-01

For centuries, beach sand has been mined for use as aggregate in concrete, for heavy minerals, and for construction fill. The global extent and impact of this phenomenon has gone relatively unnoticed by academics, NGOs, and major news sources. Most reports of sand mining activities are found at the very local scale (if the mining is ever documented at all). Yet, sand mining in many localities has resulted in the complete destruction of beach (and related) ecosystems along with severe impacts to coastal protection and tourism. The Program for the Study of Developed Shorelines at Western Carolina University and Beachcare.org have initiated the construction of a global database of beach sand mining activities. The database is being built through a combination of site visits and through the data mining of media resources, peer reviewed papers, and reports from private and governmental entities. Currently, we have documented sand mining in 35 countries on 6 continents representing the removal of millions of cubic meters of sand. Problems extend from Asia where critical infrastructure has been disrupted by sand mining to the Caribbean where policy reform has swiftly followed a highly publicized theft of sand. The Program for the Study of Developed Shorelines recently observed extensive sand mining in Morocco at the regional scale. Tens of kilometers of beach have been stripped of sand and the mining continues southward reducing hope of a thriving tourism-based economy. Problems caused by beach sand mining include: destruction of natural beaches and the ecosystems they protect (e.g. dunes, wetlands), habitat loss for globally important species (e.g. turtles, shorebirds), destruction of nearshore marine ecosystems, increased shoreline erosion rates, reduced protection from storms, tsunamis, and wave events, and economic losses through tourist abandonment and loss of coastal aesthetics. The threats posed by sand mining are made even more critical given the prospect of a

Advanced Techniques for Simulating the Behavior of Sand

NASA Astrophysics Data System (ADS)

Clothier, M.; Bailey, M.

2009-12-01

Computer graphics and visualization techniques continue to provide untapped research opportunities, particularly when working with earth science disciplines. Through collaboration with the Oregon Space Grant and IGERT Ecosystem Informatics programs we are developing new techniques for simulating sand. In addition, through collaboration with the Oregon Space Grant, we’ve been communicating with the Jet Propulsion Laboratory (JPL) to exchange ideas and gain feedback on our work. More specifically, JPL’s DARTS Laboratory specializes in planetary vehicle simulation, such as the Mars rovers. This simulation utilizes a virtual "sand box" to test how planetary rovers respond to different terrains while traversing them. Unfortunately, this simulation is unable to fully mimic the harsh, sandy environments of those found on Mars. Ideally, these simulations should allow a rover to interact with the sand beneath it, particularly for different sand granularities and densities. In particular, there may be situations where a rover may become stuck in sand due to lack of friction between the sand and wheels. In fact, in May 2009, the Spirit rover became stuck in the Martian sand and has provided additional motivation for this research. In order to develop a new sand simulation model, high performance computing will play a very important role in this work. More specifically, graphics processing units (GPUs) are useful due to their ability to run general purpose algorithms and ability to perform massively parallel computations. In prior research, simulating vast quantities of sand has been difficult to compute in real-time due to the computational complexity of many colliding particles. With the use of GPUs however, each particle collision will be parallelized, allowing for a dramatic performance increase. In addition, spatial partitioning will also provide a speed boost as this will help limit the number of particle collision calculations. However, since the goal of this

Insights into the sand fly saliva: Blood-feeding and immune interactions between sand flies, hosts, and Leishmania.

PubMed

Lestinova, Tereza; Rohousova, Iva; Sima, Michal; de Oliveira, Camila I; Volf, Petr

2017-07-01

Leishmaniases are parasitic diseases present worldwide that are transmitted to the vertebrate host by the bite of an infected sand fly during a blood feeding. Phlebotomine sand flies inoculate into the mammalian host Leishmania parasites embedded in promastigote secretory gel (PSG) with saliva, which is composed of a diverse group of molecules with pharmacological and immunomodulatory properties. In this review, we focus on 3 main aspects of sand fly salivary molecules: (1) structure and composition of salivary glands, including the properties of salivary molecules related to hemostasis and blood feeding, (2) immunomodulatory properties of salivary molecules and the diverse impacts of these molecules on leishmaniasis, ranging from disease exacerbation to vaccine development, and (3) use of salivary molecules for field applications, including monitoring host exposure to sand flies and the risk of Leishmania transmission. Studies showed interesting differences between salivary proteins of Phlebotomus and Lutzomyia species, however, no data were ever published on salivary proteins of Sergentomyia species. In the last 15 years, numerous studies have characterized sand fly salivary proteins and, in parallel, have addressed the impact of such molecules on the biology of the host-sand fly-parasite interaction. The results obtained shall pave the way for the development of field-application tools that could contribute to the management of leishmaniasis in endemic areas.

The Lived Experiences of Single Hispanic Mothers Raising Gang-Affiliated Male Youth Released from Texas Juvenile Justice Department State Facilities: A Phenomenological Study

ERIC Educational Resources Information Center

Rodriguez-Almendarez, Ruby

2013-01-01

Purpose of the Study: The purpose of this transcendental phenomenological study (Moustakas, 1994) was to describe the experiences that single Hispanic mothers of gang-affiliated male juveniles face during their sons' reentry process after being released from a Texas Juvenile Justice Department state facility. Methods: After an extensive review of…

Recognizing interactions among lumber grading rules, gang-ripping technology, and industry needs could increase the use of No.2 Common lumber

Treesearch

Charles J. Gatchell; Charles J. Gatchell

1989-01-01

Recognizing the interactions among lumber grading rules, gang-ripping technology, and the parts needs of the furniture and cabinet industries could increase the use of No. 2 Common lumber as a raw material. The minimum piece size used in establishing the No.2 Common grade is 3 inches by 2 feet. Industry often needs shorter and narrower pieces than this. No.2 Common...

Treating tar sands formations with karsted zones

DOEpatents

Vinegar, Harold J.; Karanikas, John Michael

2010-03-09

Methods for treating a tar sands formation are described herein. The tar sands formation may have one or more karsted zones. Methods may include providing heat from one or more heaters to one or more karsted zones of the tar sands formation to mobilize fluids in the formation. At least some of the mobilized fluids may be produced from the formation.

Behavior of plastic sand confinement grids

DOT National Transportation Integrated Search

1986-01-01

The concept of improving the load carrying ability of unbound aggregates, particularly sand, by lateral confinement has been investigated for some time. Extensive full-scale testing of the trafficability of confined beach sand pavement layers has bee...

The physics of wind-blown sand and dust

NASA Astrophysics Data System (ADS)

Kok, Jasper F.; Parteli, Eric J. R.; Michaels, Timothy I.; Karam, Diana Bou

2012-10-01

The transport of sand and dust by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This paper presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.