7,896 research outputs found
Measuring the Regional Economic Response to Hurricane Katrina
Naturkatastrophe; Sturm; Makroökonomischer Einfluss; USA
Dune field pattern formation and recent transporting winds in the Olympia Undae Dune Field, north polar region of Mars
High-Resolution Imaging Science Experiment (HiRISE) imagery of the central Olympia Undae Dune Field in the north polar region of Mars shows a reticulate dune pattern consisting of two sets of nearly orthogonal dune crestlines, with apparent slipfaces on the primary crests, ubiquitous wind ripples, areas of coarse-grained wind ripples, and deflated interdune areas. Geomorphic evidence and dune field pattern analysis of dune crest length, spacing, defect density, and orientation indicates that the pattern is complex, representing two constructional generations of dunes. The oldest and best-organized generation forms the primary crestlines and is transverse to circumpolar easterly winds. Gross bed form-normal analysis of the younger pattern of crestlines indicates that it emerged with both circumpolar easterly winds and NE winds and is reworking the older pattern. Mapping of secondary flow fields over the dunes indicates that the most recent transporting winds were from the NE. The younger pattern appears to represent an influx of sediment to the dune field associated with the development of the Olympia Cavi reentrant, with NE katabatic winds channeling through the reentrant. A model of the pattern reformation based upon the reconstructed primary winds and resulting secondary flow fields shows that the development of the secondary pattern is controlled by the boundary condition of the older dune topography
Disaster Loses in the Developing World: Evidence from the August 1999 Earthquake in Turkey
The purpose of this study is to investigate the impacts of a natural disaster on a developing country’s economy. In that sense, we look at the impact of August 1999 earthquake in Turkey on two important macroeconomic indicators of the Turkish economy (Real Output and Employment) with recovery policies followed by the government and international donors. Our results indicate that the earthquake had a significant immediate negative impact on both output and employment growth in Turkey. While output growth reverted back to its predisaster pattern after the initial shock, employment growth did not recover. The earthquake had both a short run and long run influence on the Turkish economy. This study will develop understanding of the possible effects of future earthquakes. Also, it will help the Turkish Government evaluate already-applied mitigation measures (like Turkish Catastrophe Insurance Pool etc.) and guide the preparation for forthcoming disasters since scientists have reached a consensus that a major earthquake is expected in Istanbul.
Dosimetric impact of gastrointestinal air column in radiation treatment of pancreatic cancer
OBJECTIVE:
Dosimetric evaluation of air column in gastrointestinal (GI) structures in intensity modulated radiation therapy (IMRT) of pancreatic cancer.
METHODS:
Nine sequential patients were retrospectively chosen for dosimetric analysis of air column in the GI apparatus in pancreatic cancer using cone beam CT (CBCT). The four-dimensional CT (4DCT) was used for target and organs at risk (OARs) and non-coplanar IMRT was used for treatment. Once a week, these patients underwent CBCT for air filling, isocentre verification and dose calculations retrospectively.
RESULTS:
Abdominal air column variation was as great as ±80% between weekly CBCT and 4DCT. Even with such a large air column in the treatment path for pancreatic cancer, changes in anteroposterior dimension were minimal (2.8%). Using IMRT, variations in air column did not correlate dosimetrically with large changes in target volume. An average dosimetric deviation of mere -3.3% and a maximum of -5.5% was observed.
CONCLUSION:
CBCT revealed large air column in GI structures; however, its impact is minimal for target coverage. Because of the inherent advantage of segmentation in IMRT, where only a small fraction of a given beam passes through the air column, this technique might have an advantage over 3DCRT in treating upper GI malignancies where the daily air column can have significant impact. Advances in knowledge: Radiation treatment of pancreatic cancer has significant challenges due to positioning, imaging of soft tissues and variability of air column in bowels. The dosimetric impact of variable air column is retrospectively studied using CBCT. Even though, the volume of air column changes by ± 80%, its dosimetric impact in IMRT is minimum
A Bayesian Updating Framework for Simulating Marine Energy Converter Drive Train Reliability
This is the author accepted manuscript. The final version is available from METSINTRODUCTION: Accurately quantifying and assessing the reliability of Marine Energy Converters (MEC’s) is critical for the successful commercialization of the industry. Without improvements in reliability and hence reductions in operation & maintenance (O&M) costs, the industry will struggle to reach competitive Levelised Cost of Energy (LCoE). At present, due to the nascent stage of the industry and commercial sensitivities there is very little reliability field data available. This presents an issue: how can the reliability of MEC devices be accurately assessed and predicted with a lack of specific reliability data? [...]The support of the ETI and RCUK Energy Program funding for IDCORE (EP/J500847/1) is gratefully acknowledged
Distinct information critically distinguishes judgments of face familiarity and identity
Accurately determining the familiarity of another and correctly establishing their identity are vital social skills. A considerable body of work has explored their perceptual and neural underpinnings and debate remains regarding whether they are dissociable, i.e., separable parts of a dual process, or different aspects of a common retrieval process. Less is known about the specific visual information that guides familiarity judgments and how this compares to the information used to identify a face by name. Here we sought to establish the critical information underlying participants’ judgments of facial familiarity and identification. We created a new standardized stimulus set comprising 6 personally familiar and 12 unfamiliar faces and applied the Bubbles reverse-correlation methodology to establish the information driving correct performance in each task. Results revealed that markedly different information underlies familiarity and identity judgments. When categorizing familiarity, participants relied more upon lower spatial-frequency, broad facial cues (eye and face shape) than when categorizing identity, which relied on fine details in the internal features (eyes and mouth). These results provide novel evidence of qualitatively distinct information use in familiarity and identification judgments and emphasize the importance of considering the task set for participants and their processing strategy when investigating face recognition
Loop quantum cosmology of Bianchi type IX models
The loop quantum cosmology "improved dynamics" of the Bianchi type IX model
are studied. The action of the Hamiltonian constraint operator is obtained via
techniques developed for the Bianchi type I and type II models, no new input is
required. It is shown that the big bang and big crunch singularities are
resolved by quantum gravity effects. We also present the effective equations
which provide modifications to the classical equations of motion due to quantum
geometry effects.Comment: 20 page
Disaster Loses in the Developing World: Evidence from the August 1999 Earthquake in Turkey
The purpose of this study is to investigate the impacts of a natural disaster on a developing countrys economy. In that sense, we look at the impact of August 1999 earthquake in Turkey on two important macroeconomic indicators of the Turkish economy (Real Output and Employment) with recovery policies followed by the government and international donors. Our results indicate that the earthquake had a significant immediate negative impact on both output and employment growth in Turkey. While output growth reverted back to its predisaster pattern after the initial shock, employment growth did not recover. The earthquake had both a short run and long run influence on the Turkish economy. This study will develop understanding of the possible effects of future earthquakes. Also, it will help the Turkish Government evaluate already-applied mitigation measures (like Turkish Catastrophe Insurance Pool etc.) and guide the preparation for forthcoming disasters since scientists have reached a consensus that a major earthquake is expected in Istanbul
Sediment Sorting and Rounding in a Basaltic Glacio-Fluvio-Aeolian Environment: hrisjkull Glacier, Iceland
Sediments and sedimentary rocks preserve a rich history of environment and climate. Identifying these signals requires an understanding of the physical and chemical processes that have affected sedimentary deposits [1]. Such processes include sorting and rounding during transport and chemical alteration through weathering and diagenesis. Although these processes have long been studied in quartz-dominated sedimentary systems [2], a lack of studies of basaltic sedimentary systems limits our interpretations of the environment and climate where mafic source rocks dominate, such as on Mars [3,4]. As part of the SAND-E: Semi-Autonomous Navigation for Detrital Environments project [5], which uses robotic operations to examine physical and chemical changes to sediments in basaltic glacio-fluvialaeolian environments, this research studies changes in sorting and rounding of fluvial-aeolian sediments along a glacier-proximal-to-glacier-distal transect in the outwash-plain of the risjkull glacier in SW Iceland (Fig. 1
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