ENVIRONMENTAL MONITORING AT GROUND ZERO AND LOWER MANHATTAN FOLLOWING THE COLLAPSE OF THE WTC

EPA Science Inventory

The U.S. EPA National Exposure Research Laboratory (NERL), in conjunction with our Regional offices, established a network of air monitoring sites to characterize ambient air concentrations of gases and particles in lower Manhattan following the collapse of the World Trade Cent...

CONCENTRATIONS AND SPECIATION OF PM AT GROUND ZERO AND LOWER MANHATTAN FOLLOWING THE COLLAPSE OF THE WTC

EPA Science Inventory

The U.S. EPA National Exposure Research Laboratory (NERL), in conjunction with our Regional offices, established a network of air monitoring sites to characterize ambient air concentrations of gases and particles in lower Manhattan following the collapse of the World Trade Cent...

CONCENTRATIONS AND COMPOSITION OF PM AT GROUND ZERO AND LOWER MANHATTAN FOLLOWING THE COLLAPSE OF THE WTC

EPA Science Inventory

The U.S. EPA National Exposure Research Laboratory (NERL), in conjunction with our Regional offices, established a network of air monitoring sites to characterize ambient air concentrations of gases and particles in lower Manhattan following the collapse of the World Trade Cent...

Newtonian semiclassical gravity in three ontological quantum theories that solve the measurement problem: Formalisms and empirical predictions

NASA Astrophysics Data System (ADS)

Derakhshani, Maaneli

In this thesis, we consider the implications of solving the quantum measurement problem for the Newtonian description of semiclassical gravity. First we review the formalism of the Newtonian description of semiclassical gravity based on standard quantum mechanics---the Schroedinger-Newton theory---and two well-established predictions that come out of it, namely, gravitational 'cat states' and gravitationally-induced wavepacket collapse. Then we review three quantum theories with 'primitive ontologies' that are well-known known to solve the measurement problem---Schroedinger's many worlds theory, the GRW collapse theory with matter density ontology, and Nelson's stochastic mechanics. We extend the formalisms of these three quantum theories to Newtonian models of semiclassical gravity and evaluate their implications for gravitational cat states and gravitational wavepacket collapse. We find that (1) Newtonian semiclassical gravity based on Schroedinger's many worlds theory is mathematically equivalent to the Schroedinger-Newton theory and makes the same predictions; (2) Newtonian semiclassical gravity based on the GRW theory differs from Schroedinger-Newton only in the use of a stochastic collapse law, but this law allows it to suppress gravitational cat states so as not to be in contradiction with experiment, while allowing for gravitational wavepacket collapse to happen as well; (3) Newtonian semiclassical gravity based on Nelson's stochastic mechanics differs significantly from Schroedinger-Newton, and does not predict gravitational cat states nor gravitational wavepacket collapse. Considering that gravitational cat states are experimentally ruled out, but gravitational wavepacket collapse is testable in the near future, this implies that only the latter two are viable theories of Newtonian semiclassical gravity and that they can be experimentally tested against each other in future molecular interferometry experiments that are anticipated to be capable of testing the gravitational wavepacket collapse prediction.

Cardiovascular risk and mortality in end-stage renal disease patients undergoing dialysis: sleep study, pulmonary function, respiratory mechanics, upper airway collapsibility, autonomic nervous activity, depression, anxiety, stress and quality of life: a prospective, double blind, randomized controlled clinical trial.

PubMed

dos Reis Santos, Israel; Danaga, Aline Roberta; de Carvalho Aguiar, Isabella; Oliveira, Ezequiel Fernandes; Dias, Ismael Souza; Urbano, Jessica Julioti; Martins, Aline Almeida; Ferraz, Leonardo Macario; Fonsêca, Nina Teixeira; Fernandes, Virgilio; Fernandes, Vinicius Alves Thomaz; Lopes, Viviane Cristina Delgado; Leitão Filho, Fernando Sérgio Studart; Nacif, Sérgio Roberto; de Carvalho, Paulo de Tarso Camillo; Sampaio, Luciana Maria Malosá; Giannasi, Lílian Christiane; Romano, Salvatore; Insalaco, Giuseppe; Araujo, Ana Karina Fachini; Dellê, Humberto; Souza, Nadia Karina Guimarães; Giannella-Neto, Daniel; Oliveira, Luis Vicente Franco

2013-10-08

Chronic kidney disease (CKD) is one of the most serious public health problems. The increasing prevalence of CKD in developed and developing countries has led to a global epidemic. The hypothesis proposed is that patients undergoing dialysis would experience a marked negative influence on physiological variables of sleep and autonomic nervous system activity, compromising quality of life. A prospective, consecutive, double blind, randomized controlled clinical trial is proposed to address the effect of dialysis on sleep, pulmonary function, respiratory mechanics, upper airway collapsibility, autonomic nervous activity, depression, anxiety, stress and quality of life in patients with CKD. The measurement protocol will include body weight (kg); height (cm); body mass index calculated as weight/height(2); circumferences (cm) of the neck, waist, and hip; heart and respiratory rates; blood pressures; Mallampati index; tonsil index; heart rate variability; maximum ventilatory pressures; negative expiratory pressure test, and polysomnography (sleep study), as well as the administration of specific questionnaires addressing sleep apnea, excessive daytime sleepiness, depression, anxiety, stress, and quality of life. CKD is a major public health problem worldwide, and its incidence has increased in part by the increased life expectancy and increasing number of cases of diabetes mellitus and hypertension. Sleep disorders are common in patients with renal insufficiency. Our hypothesis is that the weather weight gain due to volume overload observed during interdialytic period will influence the degree of collapsibility of the upper airway due to narrowing and predispose to upper airway occlusion during sleep, and to investigate the negative influences of haemodialysis in the physiological variables of sleep, and autonomic nervous system, and respiratory mechanics and thereby compromise the quality of life of patients. The protocol for this study is registered with the Brazilian Registry of Clinical Trials (ReBEC RBR-7yhr4w and World Health Organization under Universal Trial Number UTN: U1111-1127-9390 [http://www.ensaiosclinicos.gov.br/rg/RBR-7yhr4w/]).

Sensitization of Upper Airway Mechanoreceptors as a New Pharmacologic Principle to Treat Obstructive Sleep Apnea: Investigations with AVE0118 in Anesthetized Pigs

PubMed Central

Wirth, Klaus J.; Steinmeyer, Klaus; Ruetten, Hartmut

2013-01-01

Study Objectives: Drug treatment for obstructive sleep apnea (OSA) is desirable because at least 30% of patients do not tolerate continuous positive airway pressure (CPAP) treatment. The negative pressure reflex (NPR) involving superficially located mechanoreceptors in the upper airway (UA) is an important mechanism for UA patency inhibitable by topical UA anesthesia (lidocaine). The NPR may serve as a target for pharmacological intervention for a topical treatment of OSA. The objective was to determine the effect of pharmacological augmentation of the NPR on UA collapsibility. Design: We developed a model of UA collapsibility in which application of negative pressures caused UA collapses in spontaneously breathing α-chloralose-urethane anesthetized pigs as indicated by characteristic tracheal pressure and air flow changes. Setting: N/A. Patients or Participants: N/A. Interventions: N/A. Measurements and Results: The potassium channel blocker AVE0118 administered topically to the UA in doses of 1, 3, and 10 mg per nostril sensitized the NPR, shifting the mechanoreceptor response threshold for the genioglossus muscle to more positive pressures (P < 0.001; n = 6 per group) and dose-dependently inhibited UA collapsibility. Ten mg of AVE0118 prevented UA collapses against negative pressures of -150 mbar (P < 0.01) for > 4 h in all pigs, while in control pigs the UA collapsed at -50 mbar or less negative pressures. The effect of AVE0118 was abolished by UA lidocaine anesthesia. Acute intravenous administration of naloxone or acetazolamide was ineffective; paroxetine and mirtazepine were weakly effective and fluoxetine was moderately effective in line with reported clinical efficacy. Conclusion: Topical administration of AVE0118 to the UA is a promising pharmacologic approach for the treatment of OSA. Citation: Wirth KJ; Steinmeyer K; Ruetten H. Sensitization of upper airway mechanoreceptors as a new pharmacologic principle to treat obstructive sleep apnea: investigations with AVE0118 in anesthetized pigs. SLEEP 2013;36(5):699-708. PMID:23633752

Nonspherically Symmetric Collapse in Asymptotically AdS Spacetimes.

PubMed

Bantilan, Hans; Figueras, Pau; Kunesch, Markus; Romatschke, Paul

2017-11-10

We numerically simulate gravitational collapse in asymptotically anti-de Sitter spacetimes away from spherical symmetry. Starting from initial data sourced by a massless real scalar field, we solve the Einstein equations with a negative cosmological constant in five spacetime dimensions and obtain a family of nonspherically symmetric solutions, including those that form two distinct black holes on the axis. We find that these configurations collapse faster than spherically symmetric ones of the same mass and radial compactness. Similarly, they require less mass to collapse within a fixed time.

Recoverable and Programmable Collapse from Folding Pressurized Origami Cellular Solids.

PubMed

Li, S; Fang, H; Wang, K W

2016-09-09

We report a unique collapse mechanism by exploiting the negative stiffness observed in the folding of an origami solid, which consists of pressurized cells made by stacking origami sheets. Such a collapse mechanism is recoverable, since it only involves rigid folding of the origami sheets and it is programmable by pressure control and the custom design of the crease pattern. The collapse mechanism features many attractive characteristics for applications such as energy absorption. The reported results also suggest a new branch of origami study focused on its nonlinear mechanics associated with folding.

Nonspherically Symmetric Collapse in Asymptotically AdS Spacetimes

NASA Astrophysics Data System (ADS)

Bantilan, Hans; Figueras, Pau; Kunesch, Markus; Romatschke, Paul

2017-11-01

We numerically simulate gravitational collapse in asymptotically anti-de Sitter spacetimes away from spherical symmetry. Starting from initial data sourced by a massless real scalar field, we solve the Einstein equations with a negative cosmological constant in five spacetime dimensions and obtain a family of nonspherically symmetric solutions, including those that form two distinct black holes on the axis. We find that these configurations collapse faster than spherically symmetric ones of the same mass and radial compactness. Similarly, they require less mass to collapse within a fixed time.

Particle creation in (2+1) circular dust collapse

NASA Astrophysics Data System (ADS)

Gutti, Sashideep; Singh, T. P.

2007-09-01

We investigate the quantum particle creation during the circularly symmetric collapse of a 2+1 dust cloud, for the cases when the cosmological constant is either zero or negative. We derive the Ford-Parker formula for the 2+1 case, which can be used to compute the radiated quantum flux in the geometric optics approximation. It is shown that no particles are created when the collapse ends in a naked singularity, unlike in the 3+1 case. When the collapse ends in a Banados-Teitelboim-Zanelli black hole, we recover the expected Hawking radiation.

Physical properties and collapse force of according to the z-position of poly-Si pattern using nano-tribology.

PubMed

Kim, Soo In; Lee, Chang Woo

2011-02-01

Nowadays, many researchers try to measure the collapse force of fine pattern. However, most of the researches use LFM to gauge it indirectly and LFM can measure not for collapse force directly but only limited for horizontal force. Thus, nano-scratch is suggested to measure the collapse force possibly. We used poly-Si pattern on Si plate and changed the z-location of the pattern. From these experiments, the stiffness was decease as depth increase from surface and well fitted with negative exponential curve. Also, the elastic modulus was decreased. From the results, the collapse force of poly-Si nano-patterns was decreased as the depth increased over than 30% from the surface and the maximum collapse force was 26.91 microN and pattern was collapsed between poly-Si and plate.

Climate and the collapse of civilization

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

Abate, T.

1994-09-01

This article looks at the archaeological debate over two important questions: whether abrupt climate changes caused or contributed to the collapse of ancient civilizations and, if the archaeological and paleoclimatological record yields evidence to that effect, what would it mean in a world that today debates whether industrial civilization is altering Earth's climate with uncertain consequences. Areas discussed include the following: climate hints from archaeological sites; hesitations about whether climate change caused civilizations to collapse; and the interdisciplinary checks on each side.

MISR Featured Articles

Atmospheric Science Data Center

2017-09-14

... change, and ultraviolet rays. Following the World Trade Center plume  - Remote sensing helps track the drift of harmful pollutants following the World Trade Center collapse. Cloudy with a chance of Drizzle  - By analyzing ...

Environmental Roots of the Late Bronze Age Crisis

PubMed Central

Kaniewski, David; Van Campo, Elise; Guiot, Joël; Le Burel, Sabine; Otto, Thierry; Baeteman, Cecile

2013-01-01

The Late Bronze Age world of the Eastern Mediterranean, a rich linkage of Aegean, Egyptian, Syro-Palestinian, and Hittite civilizations, collapsed famously 3200 years ago and has remained one of the mysteries of the ancient world since the event’s retrieval began in the late 19th century AD/CE. Iconic Egyptian bas-reliefs and graphic hieroglyphic and cuneiform texts portray the proximate cause of the collapse as the invasions of the “Peoples-of-the-Sea” at the Nile Delta, the Turkish coast, and down into the heartlands of Syria and Palestine where armies clashed, famine-ravaged cities abandoned, and countrysides depopulated. Here we report palaeoclimate data from Cyprus for the Late Bronze Age crisis, alongside a radiocarbon-based chronology integrating both archaeological and palaeoclimate proxies, which reveal the effects of abrupt climate change-driven famine and causal linkage with the Sea People invasions in Cyprus and Syria. The statistical analysis of proximate and ultimate features of the sequential collapse reveals the relationships of climate-driven famine, sea-borne-invasion, region-wide warfare, and politico-economic collapse, in whose wake new societies and new ideologies were created. PMID:23967146

Mount St. Helens (Washington, USA) and World Trade Center (New York, USA) collapse: a fluid dynamic analogy

NASA Astrophysics Data System (ADS)

Doronzo, Domenico; de Tullio, Marco; Pascazio, Giuseppe; Dellino, Pierfrancesco

2013-04-01

When a skyscraper collapses, the non-fragmented material is rapidly deposited close to the source, whereas the fragmented counterpart is loaded turbulently in the associated currents. Indeed, on impact with the ground, collapses of volcanic columns, domes, or sectors of volcanoes generate thick deposits of coarser material, and from there on the finer material is suspended over the landscape, to be re-deposited far away in thin deposits. Here, we explore the multiphase fluid dynamic behavior of the World Trade Center (New York, USA) collapse, which on 11 September 2001 followed the fragmentation of the Twin Towers, and generated shear dusty currents. These currents had a multiphase and turbulent behavior, and resemble the volcanic flow generated during the 18 May 1980 explosive eruption of Mount St. Helens (Washington, USA), in which a sector of the volcano collapsed, then a highly mobile, multiphase turbulent current followed and heavily interacted with the surrounding landscape. This analogy allows to focus on the comparison between volcanic and skyscraper collapse. A computational fluid dynamic investigation, along with a locally refined Cartesian grid, are adopted to simulate numerically the propagation of the 11 September dusty currents in Manhattan. Results of flow dynamic pressure, the parameter of volcanic hazard, and particle deposition reveal that the pressure can locally increase up to a factor 10 because of flow-building interaction. Also, the surrounding buildings make the urban setting as of a high turbulence and exponential decay of deposit thickness.

Sequestration of vacuum energy and the end of the universe.

PubMed

Kaloper, Nemanja; Padilla, Antonio

2015-03-13

Recently, we proposed a mechanism for sequestering the standard model vacuum energy that predicts that the Universe will collapse. Here we present a simple mechanism for bringing about this collapse, employing a scalar field whose potential is linear and becomes negative, providing the negative energy density required to end the expansion. The slope of the potential is chosen to allow for the expansion to last until the current Hubble time, about 10^{10} years, to accommodate our Universe. Crucially, this choice is technically natural due to a shift symmetry. Moreover, vacuum energy sequestering selects radiatively stable initial conditions for the collapse, which guarantee that immediately before the turnaround the Universe is dominated by the linear potential which drives an epoch of accelerated expansion for at least an e fold. Thus, a single, technically natural choice for the slope ensures that the collapse is imminent and is preceded by the current stage of cosmic acceleration, giving a new answer to the "why now?"

Resilience of networks to environmental stress: From regular to random networks

NASA Astrophysics Data System (ADS)

Eom, Young-Ho

2018-04-01

Despite the huge interest in network resilience to stress, most of the studies have concentrated on internal stress damaging network structure (e.g., node removals). Here we study how networks respond to environmental stress deteriorating their external conditions. We show that, when regular networks gradually disintegrate as environmental stress increases, disordered networks can suddenly collapse at critical stress with hysteresis and vulnerability to perturbations. We demonstrate that this difference results from a trade-off between node resilience and network resilience to environmental stress. The nodes in the disordered networks can suppress their collapses due to the small-world topology of the networks but eventually collapse all together in return. Our findings indicate that some real networks can be highly resilient against environmental stress to a threshold yet extremely vulnerable to the stress above the threshold because of their small-world topology.

Smoke Plume Dispersal from the World Trade Center Disaster

NASA Image and Video Library

2006-09-06

The collapse of the World Trade Center on September 11, 2001, and the fires that followed produced a noxious smoke plume, a complex mixture of tiny airborne particles and gases as seen by NASA Terra spacecraft.

Cavitation damage prediction for spallation target vessels by assessment of acoustic vibration

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

Futakawa, Masatoshi; Kogawa, Hiroyuki; Hasegawa, Shoichi

2008-01-01

Liquid-mercury target systems for MW-class spallation neutron sources are being developed around the world. Proton beams are used to induce the spallation reaction. At the moment the proton beam hits the target, pressure waves are generated in the mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel leading to negative pressure that may cause cavitation along the vessel wall. In order to estimate the cavitation erosion, i.e. the pitting damage formed by the collapse of cavitation bubbles, off-beam tests were performed by using an electric magnetic impact testing machine (MIMTM), which can impose equivalentmore » pressure pulses in mercury. The damage potential was defined based on the relationship between the pitting damage and the time-integrated acoustic vibration induced by impact due to the bubble collapses. Additionally, the damage potential was measured in on-beam tests carried out by using the proton beam at WNR (Weapons Neutron Research) facility in Los Alamos Neutron Science Center (LANSCE). In this paper, the concept of the damage potential, the relationship between the pitting damage formation and the damage potential both in off-beam and on-beam tests is shown.« less

The World of Sports Medicine

ERIC Educational Resources Information Center

Emeagwali, N. Susan

2008-01-01

Soon, the best athletes in the world will face each other at the Summer Olympics in Beijing. Many of them will sustain injuries, or seek to prevent them, and will be thankful that among their entourages are some of the best sports medicine professionals in the world. When an athlete collapses from fatigue, or something else, there will be a group…

Bubble Proliferation in Shock Wave Lithotripsy Occurs during Inertial Collapse

NASA Astrophysics Data System (ADS)

Pishchalnikov, Yuri A.; McAteer, James A.; Pishchalnikova, Irina V.; Williams, James C.; Bailey, Michael R.; Sapozhnikov, Oleg A.

2008-06-01

In shock wave lithotripsy (SWL), firing shock pulses at slow pulse repetition frequency (0.5 Hz) is more effective at breaking kidney stones than firing shock waves (SWs) at fast rate (2 Hz). Since at fast rate the number of cavitation bubbles increases, it appears that bubble proliferation reduces the efficiency of SWL. The goal of this work was to determine the basis for bubble proliferation when SWs are delivered at fast rate. Bubbles were studied using a high-speed camera (Imacon 200). Experiments were conducted in a test tank filled with nondegassed tap water at room temperature. Acoustic pulses were generated with an electromagnetic lithotripter (DoLi-50). In the focus of the lithotripter the pulses consisted of a ˜60 MPa positive-pressure spike followed by up to -8 MPa negative-pressure tail, all with a total duration of about 7 μs. Nonlinear propagation steepened the shock front of the pulses to become sufficiently thin (˜0.03 μm) to impose differential pressure across even microscopic bubbles. High-speed camera movies showed that the SWs forced preexisting microbubbles to collapse, jet, and break up into daughter bubbles, which then grew rapidly under the negative-pressure phase of the pulse, but later coalesced to re-form a single bubble. Subsequent bubble growth was followed by inertial collapse and, usually, rebound. Most, if not all, cavitation bubbles emitted micro-jets during their first inertial collapse and re-growth. After jetting, these rebounding bubbles could regain a spherical shape before undergoing a second inertial collapse. However, either upon this second inertial collapse, or sometimes upon the first inertial collapse, the rebounding bubble emerged from the collapse as a cloud of smaller bubbles rather than a single bubble. These daughter bubbles could continue to rebound and collapse for a few cycles, but did not coalesce. These observations show that the positive-pressure phase of SWs fragments preexisting bubbles but this initial fragmentation does not yield bubble proliferation, as the daughter bubbles coalesce to reform a single bubble. Instead, bubble proliferation is the product of the subsequent inertial collapses.

Hot spaghetti: Viscous gravitational collapse

NASA Astrophysics Data System (ADS)

Müller, Berndt; Schäfer, Andreas

2018-02-01

We explore the fate of matter falling into a macroscopic Schwarzschild black hole for the simplified case of a radially collapsing thin spherical shell for which the back reaction of the geometry can be neglected. We treat the internal dynamics of the in-falling matter in the framework of viscous relativistic hydrodynamics and calculate how the internal temperature of the collapsing matter evolves as it falls toward the Schwarzschild singularity. We find that viscous hydrodynamics fails when either the dissipative radial pressure exceeds the thermal pressure and the total radial pressure becomes negative, or the time scale of variation of the tidal forces acting on the collapsing matter becomes shorter than the characteristic hydrodynamic response time.

Search for neutrinos from core-collapse supernova from the global network of detectors

NASA Astrophysics Data System (ADS)

Habig, Alec; Snews working Group

2010-01-01

The Supernova Early Warning System (SNEWS) is a cooperative effort between the world's neutrino detection experiments to spread the news that a star in our galaxy has just experienced a core-collapse event and is about to become a Type II Supernova. This project exploits the ~hours time difference between neutrinos promptly escaping the nascent supernova and photons which originate when the shock wave breaks through the stellar photosphere, to give the world a chance to get ready to observe such an exciting event at the earliest possible time. A coincidence trigger between experiments is used to eliminate potential local false alarms, allowing a rapid, automated alert.

Fluoroscopic and radiographic evaluation of tracheal collapse in dogs: 62 cases (2001-2006).

PubMed

Macready, Dawn M; Johnson, Lynelle R; Pollard, Rachel E

2007-06-15

To compare the use of radiography and fluoroscopy for detection and grading of tracheal collapse in dogs. Retrospective case series. Animals-62 dogs with tracheal collapse. For each dog, tracheal collapse was confirmed fluoroscopically and lateral cervical and thoracic radiographic views were reviewed. A board-certified radiologist (who was unaware of the dogs' clinical history) evaluated the cervical, thoracic inlet, thoracic, carinal, and main stem bronchial regions in all fluoroscopic videos and radiographic images for evidence of collapse. Cervical, thoracic inlet, thoracic, and carinal regions in both radio-graphic and fluoroscopic studies were graded for collapse (0%, 25%, 50%, 75%, or 100% decrease in diameter). Lateral cervical and thoracic radiographic images were available for 54 dogs, and inspiratory and expiratory lateral cervical and thoracic radiographic images were available for 8 dogs. For detection of tracheal collapse, assessment of radiographic views was sensitive and had the best negative predictive value in the cervical and thoracic inlet regions. Assessment of radiographic views was most specific and had the best positive predictive value in the thoracic inlet, thoracic, carina, and main stem bronchial regions. Radiography underestimated the degree of collapse in all areas. Review of inspiratory and expiratory views improved the accuracy of radiography for tracheal collapse diagnosis only slightly. Compared with fluoroscopy, radiography underestimated the frequency and degree of tracheal collapse. However, radiography appears to be useful for screening dogs with potential tracheal collapse.

The Measurement of Hot-spots in Granulated Ammonium Nitrate

NASA Astrophysics Data System (ADS)

Proud, William; Field, John

2001-06-01

Ammonium Nitrate (AN) is one of the components of the most widely used explosive in the world ammonium nitrate: fuel oil mixtures (ANFO). By itself, it is an oxygen negative explosive with a large critical diameter. Hot-spots are produced in explosives by various means including gas space collapse, localised shear or friction. If these hot-spots reach critical conditions of size, temperature and duration size reaction can grow. This deflagration stage may eventually transition to detonation. This paper describes a system and presents results where high-speed image intensified photography is used to monitor the number and growth of hot spots in granular AN under a range of different impact pressures. The results can be used in detonation codes to provide a more accurate and realistic description of the initiation process.

Correlated random walks induced by dynamical wavefunction collapse

NASA Astrophysics Data System (ADS)

Bedingham, Daniel

2015-03-01

Wavefunction collapse models modify Schrödinger's equation so that it describes the collapse of a superposition of macroscopically distinguishable states as a genuine physical process [PRA 42, 78 (1990)]. This provides a basis for the resolution of the quantum measurement problem. An additional generic consequence of the collapse mechanism is that it causes particles to exhibit a tiny random diffusive motion. Furthermore, the diffusions of two sufficiently nearby particles are positively correlated -- it is more likely that the particles diffuse in the same direction than would happen if they behaved independently [PRA 89, 032713 (2014)]. The use of this effect is proposed as an experimental test of wave function collapse models in which pairs of nanoparticles are simultaneously released from nearby traps and allowed a brief period of free fall. The random displacements of the particles are then measured. The experiment must be carried out at sufficiently low temperature and pressure for the collapse effects to dominate over the ambient environmental noise. It is argued that these constraints can be satisfied by current technologies for a large class of viable wavefunction collapse models. Work supported by the Templeton World Charity Foundation.

Collapsing glomerulopathy, the Saudi Arabian scenario

PubMed Central

Husain, Sufia

2017-01-01

Objectives: To compare the clinico-pathological features of collapsing glomerulopathy (CG) at a tertiary hospital in Saudi Arabia with the world literature. Methods: In a retrospective study, all biopsy-diagnosed cases of CG between 2004-2015 were identified and analyzed, at King Khalid University Hospital, King Saud University, Riyadh. The clinico-pathological findings along with prognosis were reviewed and compared with the reported literature. Results: Thirty-one CG patients were identified, most were adult males. All the CG cases were idiopathic, all Arabs, none HIV positive, none of African descent, and none with a history of drug abuse. The number of glomeruli with collapsing lesions per biopsy ranged from 1 to 9. Other types of FSGS lesions (not otherwise specified and perihilar) were also noted. There was extensive podocyte effacement. Upon treatment, remission (complete/partial) was noted in almost half the patients; around one fourth did not respond to treatment; and one fourth progressed to end stage kidney disease (ESKD). The median time taken to develop ESKD from the time of biopsy diagnosis was 23 months. Conclusion: The clinico-pathological and prognostic correlates of CG in Saudi Arabia are comparable with that of the world literature. The management protocol at our center is the same as that practiced in different parts of the world, and the prognosis is overall poor. PMID:28439601

InSAR Measurement of Precursor and Post-Collapse Sinkhole Subsidence

NASA Astrophysics Data System (ADS)

Holley, Rachel; McCormack, Harry; Larkin, Hayley; Wooster, Michael; Thomas, Adam

2016-08-01

Sinkholes occur across the world, often posing an obvious hazard to communities, infrastructure and the environment. Regions prone to sinkhole formation can often be identified; however prediction of exact sinkhole locations and occurrences is exceedingly difficult. This case study from Wink, in the Permian Basin of Texas, demonstrates how InSAR can measure both precursor and post-collapse deformation associated with sinkholes. ERS, ALOS PALSAR and Sentinel-1A datasets are used to show precursor signals at least nine years before sinkhole formation, and post-collapse effects continuing over several decades. The rate of deformation is variable, but reaches many tens of centimetres per year during some periods.

Regular scalar collapse

NASA Astrophysics Data System (ADS)

Lasukov, V. V.

2012-06-01

It is shown that negative Scalars can claim to be the object referred to as black holes, therefore observation of black holes means observation of Scalars. In contrast to blackholes, negative Scalars contain no singularity inside. Negative Scalars can be observed from the effect of generation of ordinary matter by the Lemaître primordial atom.

Cyprus World Trouble Spot

DTIC Science & Technology

1966-04-08

transportation, and communications. It was no more than a cadre in training when violence broke out in 1963 and the army 9 Nancy Crawshaw , "Cyprus...Government.) 10. Crawshaw , Nancy. "Cyprus; Collapse of the Zurich Agreement." The World Today, Vol. 20, Aug. 1964, pp. 338-347. 11. "Cyprus, Background

A New International Order: Proposals for Making a Better World.

ERIC Educational Resources Information Center

Suter, Keith D.

The inability of national governments to solve the world's major problems is examined, and various suggestions for solving the problems through an international government and transnational action are discussed. There are four chapters. Chapter 1 discusses changes in international relations which are resulting in a collapse of the "Old…

The Sanity of Imperial Japan: How the Threat of Extinction Simplifies the Decision for War

DTIC Science & Technology

2013-03-22

perceived its national maturation hindered by the interests of other world powers; primarily the Occidentals of Great Britain and the United States. Of...Paris Peace Conference at the end of World War I, Japan had ascended to a world power. As one of the four principal signatories to the Versailles...propelling them towards an ultimate collapse. This practice was most commonly used in China where, after World War I, Western powers were

ASSESSMENT OF DIOXIN INHALATION EXPOSURES AND POTENTIAL HEALTH IMPACTS FOLLOWING THE COLLAPSE OF THE WORLD TRADE CENTER TOWERS

EPA Science Inventory

In the days following the September 11, 2001, terrorist attack on New York City's World Trade Center (WTC) towers, EPA, other federal agencies, and New York City and New York State public health and environmental authorities initiated numerous air monitoring activities to better ...

MONITORING TOXIC ORGANIC GASES AND PARTICLES NEAR THE WORLD TRADE CENTER AFTER SEPTEMBER 11, 2001

EPA Science Inventory

The September 11, 2001 attack on the World Trade Center (WTC) resulted in an intense fire and the subsequent, complete collapse of the two main structures and adjacent buildings, as well as significant damage to many surrounding buildings within and around the WTC complex. Thi...

AIR LEVELS OF CARCINOGENIC POLYCYCLIC AROMATIC HYDROCARBONS FOLLOWING THE WORLD TRADE CENTER DISASTER

EPA Science Inventory

The catastrophic collapse of the World Trade Center (WTC) on September 11, 2001, created an immense dust cloud followed by fires that emitted soot into the air of New York City (NYC) well into December. The subsequent cleanup used diesel equipment that further polluted the air un...

Exposure and Human Health Evaluation of Airborne Pollution from the World Trade Center Disaster (External Review Draft)

EPA Science Inventory

Following the collapse of the World Trade Center towers on September 11, 2001, New York State and Federal agencies initiated numerous air monitoring activities to better understand the ongoing impact of emissions from the disaster. This report focuses on these air measurement da...

SIGAR Quarterly Report to the United States Congress

DTIC Science & Technology

2016-04-30

2016 social responsibility across public- and private- sectors around the issues of youth and women’s unemployment . This modification will increase...2015;World Bank , “Afghanistan Transport Sector ,” accessed 7/8/2013; World Bank , Afghanistan Economic Update, 4/2015, pp. 19, 23; World Bank ...stolen from Kabul Bank . Before its near-collapse in 2010, Kabul Bank had been Afghanistan’s largest private bank , distributing most civil salaries

Feeding a Dragon: Ramifications of Overreacting to China’s Relative Rise

DTIC Science & Technology

2012-06-01

remain humble by how much I still must learn in this complex world , but am confident SAASS prepared me well for the endeavor. Regarding this...Of even greater significance, economic collapse could lead to a modified world order. Can American economic overextension in the short term...economic realities and assumed risk to other missions. Chinese Perspective The progress toward economic globalization and a multi-polar world is

Foundations

NASA Astrophysics Data System (ADS)

Harteveld, Casper

A building will more likely collapse if it does not have any proper foundations. Similarly, the design philosophy of Triadic Game Design (TGD) needs to reside on solid building blocks, otherwise the concept will collapse as well. In this level I will elaborate on these building blocks. First I will explain what the general idea of TGD is. It is a design philosophy, for sure, but one which stresses that an “optimum” needs to be found in a design space constituted by three different worlds: Reality, Meaning, and Play. Additionally, these worlds need to be considered simultaneously and be treated equally. The latter requires balancing the worlds which may result in different tensions, within and between two or three of the worlds. I continue by discussing each of the worlds and showing their perspective on the field of games with a meaningful purpose. From this, we clearly see that it is feasible to think of each world and that the idea makes sense. I substantiate this further by relating the notion of player and similar approaches to this framework. This level is quite a tough pill to swallow yet essential for finishing the other levels. Do not cheat or simply skip this level, but just take a big cup of coffee or tea and start reading it.

Unexpected patterns of fisheries collapse in the world's oceans.

PubMed

Pinsky, Malin L; Jensen, Olaf P; Ricard, Daniel; Palumbi, Stephen R

2011-05-17

Understanding which species are most vulnerable to human impacts is a prerequisite for designing effective conservation strategies. Surveys of terrestrial species have suggested that large-bodied species and top predators are the most at risk, and it is commonly assumed that such patterns also apply in the ocean. However, there has been no global test of this hypothesis in the sea. We analyzed two fisheries datasets (stock assessments and landings) to determine the life-history traits of species that have suffered dramatic population collapses. Contrary to expectations, our data suggest that up to twice as many fisheries for small, low trophic-level species have collapsed compared with those for large predators. These patterns contrast with those on land, suggesting fundamental differences in the ways that industrial fisheries and land conversion affect natural communities. Even temporary collapses of small, low trophic-level fishes can have ecosystem-wide impacts by reducing food supply to larger fish, seabirds, and marine mammals.

No way out? The double-bind in seeking global prosperity along with mitigated climate change

NASA Astrophysics Data System (ADS)

Garrett, T. J.

2011-04-01

In a prior study (Garrett, 2011), I introduced a simple thermodynamics-based economic growth model. By treating civilization as a whole, it was found that the global economy's current rate of energy consumption can be tied through a constant to its current accumulation of wealth. The value of the constant is λ = 9.7 ± 0.3 milliwatts per 1990 US dollar. Here, this model is coupled to a linear formulation for the evolution of atmospheric CO2 concentrations. Despite the model's extreme simplicity, multi-decadal hindcasts of trajectories in gross world product (GWP) and CO2 agree closely with recent observations. Extending the model to the future, the model implies that the well-known IPCC SRES scenarios substantially underestimate how much CO2 levels will rise for a given level of future economic prosperity. Instead, what is shown is that, like a long-term natural disaster, future greenhouse warming should be expected to retard the real growth of wealth through inflationary pressures. Because wealth is tied to rates of energy consumption through the constant λ, it follows that dangerous climate change should be a negative feedback on CO2 emission rates, and therefore the ultimate extent of greenhouse warming. Nonetheless, if atmospheric CO2 concentrations are to remain below a "dangerous" level of 450 ppmv (Hansen et al., 2007), there will have to be some combination of an unrealistically rapid rate of energy decarbonization and a near immediate collapse of civilization wealth. Effectively, civilization is in a double-bind. If civilization does not collapse quickly this century, then CO2 levels will likely end up exceeding 1000 ppmv; but, if CO2 levels rise by this much, then the danger is that civilization will gradually tend towards collapse.

Nuclear proliferation: Will the Soviet Union's collapse spawn a new arms race

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

Griffin, R.D.

Almost 30 years ago, in the midst of the US-Soviet arms race, President John F. Kennedy warned of the danger of nuclear proliferation. Ironically, now that the Cold War is over, the prospect has become a reality. The collapse of the Soviet Union may have calmed fears of a nuclear Armageddon, but it has aroused new concerns about the spread of nuclear weapons. More than a dozen nations either have or are feverishly trying to develop nuclear arsenals, including Third World nations riven by religious and territorial disputes. If the world fails to contain the spread of nuclear-weapons technology, themore » balance of power that kept relative peace during the four decades of the Cold War may be displaced by a balance of terror.« less

China's Rural Cooperative Medical Scheme: a type of health insurance or a type of health cooperative?

PubMed

Wang, Fang; Liang, Yuan

2017-03-01

The Cooperative Medical Scheme (CMS) was popular in rural China in the 1960s and 1970s, having garnered praise from the World Bank and World Health Organization as an unprecedented example of a successful health care model in a low-income developing country. However, the CMS almost collapsed in the 1980s. Based on its historical origins and main activities, we think the CMS functioned as a health cooperative rather than a health insurance scheme. Perhaps, however, the importance to the CMS of cooperation between institutions has been overestimated. Overlooked, yet equally important, has been the cooperation between health workers and farmers to target health-related risk factors associated with agricultural work and ways of life. The 'cooperative' character of the CMS includes two aspects: cooperative institutions and cooperative behaviour. Although the CMS collapsed in China, similar schemes are flourishing elsewhere in the world. In the future, in-depth analysis of these schemes is required.

Collapse of optical wave arrested by cross-phase modulation in nonlinear metamaterials

NASA Astrophysics Data System (ADS)

Zhang, Jinggui; Li, Ying; Xiang, Yuanjiang; Lei, Dajun; Zhang, Lifu

2016-03-01

In this article, we put forward a novel strategy to realize the management of wave collapse through designing probe-pump configuration where probe wave is assumed to propagate in the positive-index region of metamaterials (MMs), while pump wave is assumed to propagate in the negative-index region. We disclose that cross-phase modulation (XPM) in MMs as a new physical mechanism that can be used to arrest the collapse of probe wave in the positive-index region by copropagating it together with pump wave in the negative-index region. Further, we observe that pump wave will evolve into a ring while probe wave will develop a side lob in the wings during the course of coupled waves propagation, different from the corresponding counterpart in the ordinary positive-index materials (OMs) where they simultaneously exhibit the catastrophic self-focusing behavior. Meanwhile, we also discuss how to control the collapse of probe wave by adjusting intensity-detuned pump wave. Our analysis is performed by directly numerically solving the coupled nonlinear Schrödinger equations, as well as using the variational approximation, both showing consistent results. The finding demonstrates XPM as a specific physical mechanism in MMs can provide us unique opportunities unattainable in OMs to manipulate self-focusing of high-power laser.

Economic assessment of the construction industry: A construction-economics nexus

NASA Astrophysics Data System (ADS)

Barber, Herbert Marion, Jr.

The purpose of this study was to conduct an economic assessment of the construction industry. More specifically, this study addresses ambiguities within the literature that are associated with the construction-economics nexus. The researcher 1) investigated the relationships between economic indicators and stock prices of U.S. construction equipment manufacturers, 2) investigated the relationships between energy production, consumption, and corruption, and 3) determined the economic effect electricity generation and electricity consumption has on economies of scale. The researcher used descriptive and inferential statistics in this study and determined that economists, researchers, policy-makers, and others should have predicted the 2007-08 world economic collapse 5-6 years prior to realization of the event given that construction indices and GDP grossly regressed from statistically acceptable trends as early as 2002 and perhaps 2000. Substantiating this claim, the effect of the cost of construction materials and labor, i.e. construction index, on GDP was significant for years leading up to the collapse (1970-2007). Additionally, it was determined that energy production and consumption are predictors of governmental corruption in some countries. In the Republic of Botswana, for example, the researcher determined that energy production and consumption statistically jointly effected governmental corruption. In addition to determining statistical effect, a model for predicting governmental corruption was developed based on energy production and consumption volumes. Also, the researcher found that electricity generation in the 25 largest world economies had a statistically significant effect on GDP. Electricity consumption also had an effect on GDP, as well, but not on other economic indicators. More importantly than the quantitative findings, the researcher concluded that the construction-economics nexus is far more complex than most policy-makers realize. As such, infrastructure spending may, or may not, be an answer to the current world economic collapse, as much more research remains to be completed by researchers to address known ambiguities within various associated findings. Until a collective agreement can be reached among researchers as to the effect that construction spending has on economic output under known, specific parameters, policy-makers should exercise extreme caution when leveraging infrastructure spending as a solution for overcoming the world economic collapse.

METROPOLITAN-SCALE TRANSPORT AND DISPERSION FROM THE NEW YORK WORLD TRADE CENTER FOLLOWING SEPTEMBER 11, 2001. PART I: AN EVALUATION OF THE CALMET METEOROLOGICAL MODEL

EPA Science Inventory

Following the collapse of the New York City World Trade Center towers on September 11, 2001, Local, State and Federal agencies initiated numerous air monitoring activities to better understand the impact of emissions from the disaster. A study of the estimated pathway that a pote...

Education, Nation-Building and Modernization after World War I: American Ideas for the Peace Conference

ERIC Educational Resources Information Center

Ment, David M.

2005-01-01

The First World War ended with the collapse of the Austro-Hungarian, Russian, German and Ottoman Empires. In planning for the peace negotiations the allied governments considered not only the European boundaries but especially the national aspirations and future development of the peoples of the Balkans, the Caucasus, the Middle East, Africa and…

AIR POLLUTION MEASUREMENTS IN THE VICINITY OF THE WORLD TRADE CENTER - SUMMARY OF MEASUREMENTS CONDUCTED BY EPA-ORD

EPA Science Inventory

The U.S. Environmental Protection Agency's Office of Research and Development (EPA-ORD) was requested by EPA's Region 2 office in New York on 9/12/01 to assist with air quality monitoring in response to the collapse of the World Trade Center. Scientists at the U.S. EPA-ORD's Nati...

Subsidence and collapse sinkholes in soluble rock: a numerical perspective

NASA Astrophysics Data System (ADS)

Kaufmann, Georg; Romanov, Douchko; Hiller, Thomas

2016-04-01

Soluble rocks such as limestone, gypsum, anhydrite, and salt are prone to subsidence and the sudden creation of collapse sinkholes. The reason for this behaviour stems from the solubility of the rock: Water percolating through fissures and bedding partings can remove material from the rock walls and thus increase the permeability of the host rock by orders of magnitudes. This process occurs on time scales of 1,000-100,000 years, resulting in enlarged fractures, voids and cavities, which then carry flow efficiently through the rock. The enlargement of sub-surface voids to the meter-size within such short times creates mechanical conditions prone to collapse. The collapse initiates at depth, but then propagates to the surface. By means of numerical modelling, we discuss the long-term evolution of secondary porosity in gypsum rocks, resulting in zones of sub-surface voids, which then become mechanically unstable and collapse. We study two real-world case scenarios, in which we can relate field observations to our numerical model: (i) A dam-site scenario, where flow around the dam caused widespread dissolution of gypsum and subsequent subsidence of the dam and a nearby highway. (ii) A natural collapse sinkhole forming as a result of freshwater inflow into a shallow anhydrite formation with rapid evolution of voids in the sub-surface.

Standard model group: Survival of the fittest

NASA Astrophysics Data System (ADS)

Nielsen, H. B.; Brene, N.

1983-09-01

The essential content of this paper is related to random dynamics. We speculate that the world seen through a sub-Planck-scale microscope has a lattice structure and that the dynamics on this lattice is almost completely random, except for the requirement that the random (plaquette) action is invariant under some "world (gauge) group". We see that the randomness may lead to spontaneous symmetry breakdown in the vacuum (spontaneous collapse) without explicit appeal to any scalar field associated with the usual Higgs mechanism. We further argue that the subgroup which survives as the end product of a possible chain of collapses is likely to have certain properties; the most important is that it has a topologically connected center. The standard group, i.e. the group of the gauge theory which combines the Salam-Weinberg model with QCD, has this property.

Materials characterization of dusts generated by the collapse of the World Trade Center

USGS Publications Warehouse

Meeker, Gregory P.; Sutley, Stephen J.; Brownfield, Isabelle; Lowers, Heather; Bern, Amy M.; Swayze, Gregg A.; Hoefen, Todd M.; Plumlee, Geoffrey S.; Clark, Roger N.; Gent, Carol A.

2009-01-01

The major inorganic components of the dusts generated from the collapse of the World Trade Center buildings on September 11, 2001 were concrete materials, gypsum, and man-made vitreous fibers. These components were likely derived from lightweight Portland cement concrete floors, gypsum wallboard, and spray-on fireproofing and ceiling tiles, respectively. All of the 36 samples collected by the USGS team had these materials as the three major inorganic components of the dust. Components found at minor and trace levels include chrysotile asbestos, lead, crystalline silica, and particles of iron and zinc oxides. Other heavy metals, such as lead, bismuth, copper, molybdenum, chromium, and nickel, were present at much lower levels occurring in a variety of chemical forms. Several of these materials have health implications based on their chemical composition, morphology, and bioaccessibility.

Translations on USSR Military Affairs, Number 1303

DTIC Science & Technology

1977-09-27

descendents of the Katyusha launcher of World War II — would be subsequently installed here. At present armament consists of only the two 57mm L/80...Sciences: "It Was the 5th Year of War ..."] [Excerpts] The eighth volume has been published of the history of World War II (Footnote) (The History of... World War II, 1939-1945. In 12 volumes. Chairman of the main editorial commission: D. F. Ustinov. Volume eight: The Collapse of the Fascist Bloc’s

The risk of collapse in abandoned mine sites: the issue of data uncertainty

NASA Astrophysics Data System (ADS)

Longoni, Laura; Papini, Monica; Brambilla, Davide; Arosio, Diego; Zanzi, Luigi

2016-04-01

Ground collapses over abandoned underground mines constitute a new environmental risk in the world. The high risk associated with subsurface voids, together with lack of knowledge of the geometric and geomechanical features of mining areas, makes abandoned underground mines one of the current challenges for countries with a long mining history. In this study, a stability analysis of Montevecchia marl mine is performed in order to validate a general approach that takes into account the poor local information and the variability of the input data. The collapse risk was evaluated through a numerical approach that, starting with some simplifying assumptions, is able to provide an overview of the collapse probability. The final results is an easy-accessible-transparent summary graph that shows the collapse probability. This approach may be useful for public administrators called upon to manage this environmental risk. The approach tries to simplify this complex problem in order to achieve a roughly risk assessment, but, since it relies on just a small amount of information, any final user should be aware that a comprehensive and detailed risk scenario can be generated only through more exhaustive investigations.

Gravitational collapse in Husain space-time for Brans-Dicke gravity theory with power-law potential

NASA Astrophysics Data System (ADS)

Rudra, Prabir; Biswas, Ritabrata; Debnath, Ujjal

2014-12-01

The motive of this work is to study gravitational collapse in Husain space-time in Brans-Dicke gravity theory. Among many scalar-tensor theories of gravity, Brans-Dicke is the simplest and the impact of it can be regulated by two parameters associated with it, namely, the Brans-Dicke parameter, ω, and the potential-scalar field dependency parameter n respectively. V. Husain's work on exact solution for null fluid collapse in 1996 has influenced many authors to follow his way to find the end-state of the homogeneous/inhomogeneous dust cloud. Vaidya's metric is used all over to follow the nature of future outgoing radial null geodesics. Detecting whether the central singularity is naked or wrapped by an event horizon, by the existence of future directed radial null geodesic emitted in past from the singularity is the basic objective. To point out the existence of positive trajectory tangent solution, both particular parametric cases (through tabular forms) and wide range contouring process have been applied. Precisely, perfect fluid's EoS satisfies a wide range of phenomena: from dust to exotic fluid like dark energy. We have used the EoS parameter k to determine the end state of collapse in different cosmological era. Our main target is to check low ω (more deviations from Einstein gravity-more Brans Dicke effect) and negative k zones. This particularly throws light on the nature of the end-state of collapse in accelerated expansion in Brans Dicke gravity. It is seen that for positive values of EoS parameter k, the collapse results in a black hole, whereas for negative values of k, naked singularity is the only outcome. It is also to be noted that "low ω" leads to the possibility of getting more naked singularities even for a non-accelerating universe.

Gravitational Collapse in Husain space-time for Brans-Dicke Gravity Theory with Power-law Potential.

NASA Astrophysics Data System (ADS)

Rudra, Prabir

2016-07-01

The motive of this work is to study gravitational collapse in Husain space-time in Brans-Dicke gravity theory. Among many scalar-tensor theories of gravity, Brans-Dicke is the simplest and the impact of it can be regulated by two parameters associated with it, namely, the Brans-Dicke parameter, ω, and the potential-scalar field dependency parameter 'n' respectively. V. Husain's work on exact solution for null fluid collapse in 1996 has influenced many authors to follow his way to find the end-state of the homogeneous/inhomogeneous dust cloud. Vaidya's metric is used all over to follow the nature of future outgoing radial null geodesics. Detecting whether the central singularity is naked or wrapped by an event horizon, by the existence of future directed radial null geodesic emitted in past from the singularity is the basic objective. To point out the existence of positive trajectory tangent solution, both particular parametric cases(through tabular forms) and wide range contouring process have been applied. Precisely, perfect fluid's equation of state satisfies a wide range of phenomena : from dust to exotic fluid like dark energy. We have used the equation of state parameter 'k' to determine the end state of collapse in different cosmological era. Our main target is to check low ω (more deviations from Einstein gravity-more Brans Dicke effect) and negative 'k' zones. This particularly throws light on the nature of the end-state of collapse in accelerated expansion in Brans Dicke gravity. It is seen that for positive values of EoS parameter 'k', the collapse results in a black hole, whereas for negative values of 'k', naked singularity is the only outcome. It is also to be noted that "low ω" leads to the possibility of getting more naked singularities even for a non-accelerating universe.

What would have happened to the ozone layer if chlorofluorocarbons (CFCs) had not been regulated?

NASA Astrophysics Data System (ADS)

Oman, L.; Newman, P. A.; Douglass, A. R.; Fleming, E. L.; Frith, S. M.; Hurwitz, M.; Kawa, S. R.; Jackman, C. H.; Krotkov, N. A.; Nash, E. R.; Nielsen, J. E.; Pawson, S.; Stolarski, R. S.; Velders, G. J.

2010-12-01

The Montreal Protocol on Substances that Deplete the Ozone Layer was negotiated in 1987 and by 2010 had been signed by all of the nations of the world. In this presentation we use a fully coupled radiation-chemical-dynamical model to simulate a future world where ozone depletion substances (ODSs) were never regulated. In this “world avoided” simulation, ODS levels increase by 3% per year. From 1980 to 2020 we find that 17% of the globally average column ozone is destroyed, and from 1980 to 2065 67% is destroyed. Severe polar depletions (e.g., the Antarctic ozone hole) become year-round rather than just seasonal. Ozone levels in the tropical lower stratosphere remain constant until about 2053 and then collapse to near zero by 2058 as a result of heterogeneous chemical processes (as currently observed in the Antarctic ozone hole). The tropical cooling that triggers the ozone collapse is caused by an increase of the tropical lower stratospheric upwelling. In response to ozone changes, ultraviolet (UV) radiation increases, tripling the erythemal (sunburn) radiation in the northern summer mid-latitudes by 2065.

Structural stability of interaction networks against negative external fields

NASA Astrophysics Data System (ADS)

Yoon, S.; Goltsev, A. V.; Mendes, J. F. F.

2018-04-01

We explore structural stability of weighted and unweighted networks of positively interacting agents against a negative external field. We study how the agents support the activity of each other to confront the negative field, which suppresses the activity of agents and can lead to collapse of the whole network. The competition between the interactions and the field shape the structure of stable states of the system. In unweighted networks (uniform interactions) the stable states have the structure of k -cores of the interaction network. The interplay between the topology and the distribution of weights (heterogeneous interactions) impacts strongly the structural stability against a negative field, especially in the case of fat-tailed distributions of weights. We show that apart from critical slowing down there is also a critical change in the system structure that precedes the network collapse. The change can serve as an early warning of the critical transition. To characterize changes of network structure we develop a method based on statistical analysis of the k -core organization and so-called "corona" clusters belonging to the k -cores.

Origin of superconductivity in KFe2As2 under positive and negative pressures and relation to other Fe-based families

NASA Astrophysics Data System (ADS)

Valenti, Roser

KFe2As2 shows an intricate behavior as a function of pressure. At ambient pressure the system is superconductor with a low critical temperature Tc=3.4 K and follows a V-shaped pressure dependence of Tc for moderate pressures with a local minimum at a pressure of 1.5 GPa. Under high pressures Pc=15 GPa, KFe2As2 exhibits a structural phase transition from a tetragonal to a collapsed tetragonal phase accompanied by a boost of the superconducting critical temperature up to 12 K. On the other hand, negative pressures realized through substitution of K by Cs or Rb decrease Tc down to 2.25K. In this talk we will discuss recent progress on the understanding of the microscopic origin of this pressure-dependent behavior by considering a combination of ab initio density functional theory with dynamical mean field theory and spin fluctuation theory calculations. We will argue that a Lifshitz transition associated with the structural collapse changes the pairing symmetry from d-wave (tetragonal) to s+/- (collapsed tetragonal) at high pressures while at ambient and negative pressures correlation effects appear to be detrimental for superconductivity. Further, we shall establish cross-links to the chalcogenide family, in particular FeSe under pressure. The Deutsche Forschungsgemeinschaft (DFG) is gratefully acknowledged for financial support.

Solvation Free Energies of Alanine Peptides: The Effect of Flexibility

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

Kokubo, Hironori; Harris, Robert C.; Asthagiri, Dilip

The electrostatic (?Gel), cavity-formation (?Gvdw), and total (?G) solvation free energies for 10 alanine peptides ranging in length (n) from 1 to 10 monomers were calculated. The free energies were computed both with xed, extended conformations of the peptides and again for some of the peptides without constraints. The solvation free energies, ?Gel, ?Gvdw, and ?G, were found to be linear in n, with the slopes of the best-fit lines being gamma_el, gamma_vdw, and gamma, respectively. Both gamma_el and gamma were negative for fixed and flexible peptides, and gamma_vdw was negative for fixed peptides. That gamma_vdw was negative was surprising,more » as experimental data on alkanes, theoretical models, and MD computations on small molecules and model systems generally suggest that gamma_vdw should be positive. A negative gamma_vdw seemingly contradicts the notion that ?Gvdw drives the initial collapse of the protein when it folds by favoring conformations with small surface areas, but when we computed ?Gvdw for the flexible peptides, thereby allowing the peptides to assume natural ensembles of more compact conformations, gamma-vdw was positive. Because most proteins do not assume extended conformations, a ?Gvdw that increases with increasing surface area may be typical for globular proteins. An alternative hypothesis is that the collapse is driven by intramolecular interactions. We show that the intramolecular van der Waal's interaction energy is more favorable for the flexible than for the extended peptides, seemingly favoring this hypothesis, but the large fluctuations in this energy may make attributing the collapse of the peptide to this intramolecular energy difficult.« less

Bushmeat hunting and extinction risk to the world's mammals

PubMed Central

Abernethy, Katharine; Betts, Matthew G.; Chapron, Guillaume; Dirzo, Rodolfo; Galetti, Mauro; Levi, Taal; Lindsey, Peter A.; Macdonald, David W.; Machovina, Brian; Peres, Carlos A.; Wallach, Arian D.

2016-01-01

Terrestrial mammals are experiencing a massive collapse in their population sizes and geographical ranges around the world, but many of the drivers, patterns and consequences of this decline remain poorly understood. Here we provide an analysis showing that bushmeat hunting for mostly food and medicinal products is driving a global crisis whereby 301 terrestrial mammal species are threatened with extinction. Nearly all of these threatened species occur in developing countries where major coexisting threats include deforestation, agricultural expansion, human encroachment and competition with livestock. The unrelenting decline of mammals suggests many vital ecological and socio-economic services that these species provide will be lost, potentially changing ecosystems irrevocably. We discuss options and current obstacles to achieving effective conservation, alongside consequences of failure to stem such anthropogenic mammalian extirpation. We propose a multi-pronged conservation strategy to help save threatened mammals from immediate extinction and avoid a collapse of food security for hundreds of millions of people. PMID:27853564

Timelike naked singularity

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

Goswami, Rituparno; Joshi, Pankaj S.; Vaz, Cenalo

We construct a class of spherically symmetric collapse models in which a naked singularity may develop as the end state of collapse. The matter distribution considered has negative radial and tangential pressures, but the weak energy condition is obeyed throughout. The singularity forms at the center of the collapsing cloud and continues to be visible for a finite time. The duration of visibility depends on the nature of energy distribution. Hence the causal structure of the resulting singularity depends on the nature of the mass function chosen for the cloud. We present a general model in which the naked singularitymore » formed is timelike, neither pointlike nor null. Our work represents a step toward clarifying the necessary conditions for the validity of the Cosmic Censorship Conjecture.« less

A novel animal model for hyperdynamic airway collapse.

PubMed

Tsukada, Hisashi; O'Donnell, Carl R; Garland, Robert; Herth, Felix; Decamp, Malcolm; Ernst, Armin

2010-12-01

Tracheobronchomalacia (TBM) is increasingly recognized as a condition associated with significant pulmonary morbidity. However, treatment is invasive and complex, and because there is no appropriate animal model, novel diagnostic and treatment strategies are difficult to evaluate. We endeavored to develop a reliable airway model to simulate hyperdynamic airway collapse in humans. Seven 20-kg male sheep were enrolled in this study. Tracheomalacia was created by submucosal resection of > 50% of the circumference of 10 consecutive cervical tracheal cartilage rings through a midline cervical incision. A silicone stent was placed in the trachea to prevent airway collapse during recovery. Tracheal collapsibility was assessed at protocol-specific time points by bronchoscopy and multidetector CT imaging while temporarily removing the stent. Esophageal pressure and flow data were collected to assess flow limitation during spontaneous breathing. All animals tolerated the surgical procedure well and were stented without complications. One sheep died at 2 weeks because of respiratory failure related to stent migration. In all sheep, near-total forced inspiratory airway collapse was observed up to 3 months postprocedure. Esophageal manometry demonstrated flow limitation associated with large negative pleural pressure swings during rapid spontaneous inhalation. Hyperdynamic airway collapse can reliably be induced with this technique. It may serve as a model for evaluation of novel diagnostic and therapeutic strategies for TBM.

Ebeye 2023: Comprehensive Capacity Development Master Plan

DTIC Science & Technology

2012-07-01

the Marshall Islands, is facing a number of challenges to include overpopulation , collapsing infrastructure, a weak school system as well as a very...several islands on Kwajalein Atoll. The atoll consists of approximately 90 islets around the largest lagoon in the world . The original agreement...of the world . With this high population density the need for proper long term planning is critical. The current conditions of the city require a

The worldwide collapse caldera database (CCDB): A tool for studying and understanding caldera processes

NASA Astrophysics Data System (ADS)

Geyer, Adelina; Marti, Joan

2015-04-01

Collapse calderas are one of the most important volcanic structures not only because of their hazard implications, but also because of their high geothermal energy potential and their association with mineral deposits of economic interest. In 2008 we presented a new general worldwide Collapse Caldera DataBase (CCDB), in order to provide a useful and accessible tool for studying and understanding caldera collapse processes. The principal aim of the CCDB is to update the current field based knowledge on calderas, merging together the existing databases and complementing them with new examples found in the bibliography, and leaving it open for the incorporation of new data from future studies. Currently, the database includes over 450 documented calderas around the world, trying to be representative enough to promote further studies and analyses. We have performed a comprehensive compilation of published field studies of collapse calderas including more than 500 references, and their information has been summarized in a database linked to a Geographical Information System (GIS) application. Thus, it is possible to visualize the selected calderas on a world map and to filter them according to different features recorded in the database (e.g. age, structure). The information recorded in the CCDB can be grouped in seven main information classes: caldera features, properties of the caldera-forming deposits, magmatic system, geodynamic setting, pre-caldera volcanism,caldera-forming eruption sequence and post-caldera activity. Additionally, we have added two extra classes. The first records the references consulted for each caldera. The second allows users to introduce comments on the caldera sample such as possible controversies concerning the caldera origin. During the last seven years, the database has been available on-line at http://www.gvb-csic.es/CCDB.htm previous registration. This year, the CCDB webpage will be updated and improved so the database content can be queried on-line. This research was partially funded by the research fellowship RYC-2012-11024.

Self-generating oscillating pressure exercise device

NASA Technical Reports Server (NTRS)

Watenpaugh, Donald E. (Inventor)

1994-01-01

An exercise device, especially suitable for zero gravity workouts, has a collapsible chamber which generates negative pressure on the lower portion of a body situated therein. The negative pressure is generated by virtue of leg, hand and shoulder interaction which contracts and expands the chamber about the person and by virtue of air flow regulation by valve action.

Environment: Language Ecology and Language Death

NASA Astrophysics Data System (ADS)

Romaine, Suzanne

Global linguistic diversity is rapidly declining. As the world becomes less linguistically diverse, it is becoming culturally less diverse as well as the world's tribes and languages are dying out or being assimilated into modern civilization because their habitats are being destroyed. At the same time the world is experiencing a substantial decline in biodiversity. The extinction of languages is part of the larger picture of near total collapse of the worldwide ecosystem, and languages are vital parts of complex local ecologies that must be supported if global biodiversity is to be maintained.

Models of collapsing and expanding anisotropic gravitating source in f( R, T) theory of gravity

NASA Astrophysics Data System (ADS)

Abbas, G.; Ahmed, Riaz

2017-07-01

In this paper, we have formulated the exact solutions of the non-static anisotropic gravitating source in f( R, T) gravity which may lead to expansion and collapse. By assuming there to be no thermal conduction in gravitating source, we have determined parametric solutions in f( R, T) gravity with a non-static spherical geometry filled using an anisotropic fluid. We have examined the ranges of the parameters for which the expansion scalar becomes negative and positive, leading to collapse and expansion, respectively. Further, using the definition of the mass function, the conditions for the trapped surface have been explored, and it has been investigated that there exists a single horizon in this case. The impact of the coupling parameter λ has been discussed in detail in both cases. For the various values of the coupling parameter λ , we have plotted the energy density, anisotropic pressure and anisotropy parameter in the cases of collapse and expansion. The physical significance of the graphs has been explained in detail.

The rise of the mesopredator

USDA-ARS?s Scientific Manuscript database

Apex predators have experienced catastrophic declines throughout the world due to human persecution and habitat loss. These collapses in top predator populations are commonly associated with dramatic increases in the abundance of smaller predators. Known as ‘mesopredator release,’ this trophic inte...

Behavioral Modulation of Infestation by Varroa destructor in Bee Colonies. Implications for Colony Stability.

PubMed

de Figueiró Santos, Joyce; Coelho, Flávio Codeço; Bliman, Pierre-Alexandre

2016-01-01

Colony Collapse Disorder (CCD) has become a global problem for beekeepers and for the crops that depend on bee pollination. While many factors are known to increase the risk of colony collapse, the ectoparasitic mite Varroa destructor is considered to be the most serious one. Although this mite is unlikely to cause the collapse of hives itself, it is the vector for many viral diseases which are among the likely causes for Colony Collapse Disorder. The effects of V. destructor infestation differ from one part of the world to another, with greater morbidity and higher colony losses in European honey bees (EHB) in Europe, Asia and North America. Although this mite has been present in Brazil for many years, there have been no reports of colony losses amongst Africanized Honey Bees (AHB). Studies carried out in Mexico have highlighted different behavioral responses by the AHB to the presence of the mite, notably as far as grooming and hygienic behavior are concerned. Could these explain why the AHB are less susceptible to Colony Collapse Disorder? In order to answer this question, we have developed a mathematical model of the infestation dynamics to analyze the role of resistance behavior by bees in the overall health of the colony, and as a consequence, its ability to face epidemiological challenges.

Report by Jacques Delors, Chairman of the International Commission on Education for the Twenty-First Century, First Session (Paris, France, March 2-4, 1993).

ERIC Educational Resources Information Center

Delors, Jacques

In this paper the chairman of the International Commission on Education for the Twenty-First Century reviewed commission discussions on education in the 21st century. The growing interdependence of the modern world is discussed including the results of the U.S. economic ideology of the Ronald Reagan era on the world economy, and the collapse of…

Fishing amplifies forage fish population collapses.

PubMed

Essington, Timothy E; Moriarty, Pamela E; Froehlich, Halley E; Hodgson, Emma E; Koehn, Laura E; Oken, Kiva L; Siple, Margaret C; Stawitz, Christine C

2015-05-26

Forage fish support the largest fisheries in the world but also play key roles in marine food webs by transferring energy from plankton to upper trophic-level predators, such as large fish, seabirds, and marine mammals. Fishing can, thereby, have far reaching consequences on marine food webs unless safeguards are in place to avoid depleting forage fish to dangerously low levels, where dependent predators are most vulnerable. However, disentangling the contributions of fishing vs. natural processes on population dynamics has been difficult because of the sensitivity of these stocks to environmental conditions. Here, we overcome this difficulty by collating population time series for forage fish populations that account for nearly two-thirds of global catch of forage fish to identify the fingerprint of fisheries on their population dynamics. Forage fish population collapses shared a set of common and unique characteristics: high fishing pressure for several years before collapse, a sharp drop in natural population productivity, and a lagged response to reduce fishing pressure. Lagged response to natural productivity declines can sharply amplify the magnitude of naturally occurring population fluctuations. Finally, we show that the magnitude and frequency of collapses are greater than expected from natural productivity characteristics and therefore, likely attributed to fishing. The durations of collapses, however, were not different from those expected based on natural productivity shifts. A risk-based management scheme that reduces fishing when populations become scarce would protect forage fish and their predators from collapse with little effect on long-term average catches.

Kepler Beyond Planets: Finding Exploding Stars (Type Ia Supernova from a White Dwarf Stealing Matter)

NASA Image and Video Library

2018-03-26

This frame from an animation shows a gigantic star exploding in a "core collapse" supernova. As atoms fuse inside the star, eventually the star can't support its own weight anymore. Gravity makes the star collapse on itself. Core collapse supernovae are called type Ib, Ic, or II depending on the chemical elements present. Stellar explosions forge and distribute materials that make up the world in which we live, and also hold clues to how fast the universe is expanding. By understanding supernovae, scientists can unlock mysteries that are key to what we are made of and the fate of our universe. But to get the full picture, scientists must observe supernovae from a variety of perspectives, especially in the first moments of the explosion. That's really difficult -- there's no telling when or where a supernova might happen next. An animation is available at https://photojournal.jpl.nasa.gov/catalog/PIA22352

Report: Survey of Air Quality Information Related to the World Trade Center Collapse

EPA Pesticide Factsheets

Report #2003-P-00014, September 26, 2003. Overall, the majority of respondents wanted more information regarding outdoor and indoor air quality, wanted this information in a more timely manner, and did not believe the information they received.

Non-singular Brans-Dicke collapse in deformed phase space

NASA Astrophysics Data System (ADS)

Rasouli, S. M. M.; Ziaie, A. H.; Jalalzadeh, S.; Moniz, P. V.

2016-12-01

We study the collapse process of a homogeneous perfect fluid (in FLRW background) with a barotropic equation of state in Brans-Dicke (BD) theory in the presence of phase space deformation effects. Such a deformation is introduced as a particular type of non-commutativity between phase space coordinates. For the commutative case, it has been shown in the literature (Scheel, 1995), that the dust collapse in BD theory leads to the formation of a spacetime singularity which is covered by an event horizon. In comparison to general relativity (GR), the authors concluded that the final state of black holes in BD theory is identical to the GR case but differs from GR during the dynamical evolution of the collapse process. However, the presence of non-commutative effects influences the dynamics of the collapse scenario and consequently a non-singular evolution is developed in the sense that a bounce emerges at a minimum radius, after which an expanding phase begins. Such a behavior is observed for positive values of the BD coupling parameter. For large positive values of the BD coupling parameter, when non-commutative effects are present, the dynamics of collapse process differs from the GR case. Finally, we show that for negative values of the BD coupling parameter, the singularity is replaced by an oscillatory bounce occurring at a finite time, with the frequency of oscillation and amplitude being damped at late times.

Postural Effects on Pharyngeal Protective Reflex Mechanisms

PubMed Central

Malhotra, Atul; Trinder, John; Fogel, Robert; Stanchina, Michael; Patel, Sanjay R.; Schory, Karen; Kleverlaan, Darci; White, David P.

2012-01-01

Study Objectives Pharyngeal muscle dilators are important in obstructive sleep apnea pathogenesis because the failure of protective reflexes involving these muscles yields pharyngeal collapse. Conflicting results exist in the literature regarding the responsiveness of these muscles during stable non-rapid eye movement sleep. However, variations in posture in previous studies may have influenced these findings. We hypothesized that tongue protruder muscles are maximally responsive to negative pressure pulses during supine sleep, when posterior tongue displacement yields pharyngeal occlusion. Design We studied all subjects in the supine and lateral postures during wakefulness and stable non-rapid eye movement sleep by measuring genioglossus and tensor palatini electromyograms during basal breathing and following negative pressure pulses. Setting Upper-airway physiology laboratory of Sleep Medicine Division, Brigham and Women’s Hospital. Subjects/Participants 17 normal subjects. Measurements and Results We observed an increase in genioglossal responsiveness to negative pressure pulses in sleep as compared to wakefulness in supine subjects (3.9 percentage of maximum [%max] ± 1.1 vs 4.4 %max ± 1.0) but a decrease in the lateral decubitus position (4.1 %max ± 1.0 vs 1.5 %max ± 0.4), the interaction effect being significant. Despite this augmented reflex, collapsibility, as measured during negative pressure pulses, increased more while subjects were in the supine position as compared with the lateral decubitus position. While the interaction between wake-sleep state and position was also significant for the tensor palatini, the effect was weaker than for genioglossus, although, for tensor palatini, baseline activity was markedly reduced during non-rapid eye movement sleep as compared with wakefulness. Conclusions We conclude that body posture does have an important impact on genioglossal responsiveness to negative pressure pulses during non-rapid eye movement sleep. We speculate that this mechanism works to prevent pharyngeal occlusion when the upper airway is most vulnerable to collapse eg, during supine sleep. PMID:15532204

Shock-induced nanobubble collapse and its applications

NASA Astrophysics Data System (ADS)

Vedadi, Mohammad Hossein

The shock-induced collapse of nanobubbles in water is investigated using molecular dynamics simulations based on a reactive force field. Monitoring the collapse of a cavitation nanobubble, we observe a focused nanojet at the onset of bubble shrinkage and a water hammer shock wave upon bubble collapse. The nanojet length scales linearly with the nanobubble radius, as observed in experiments on micron-to-millimeter size bubbles. The shock induces dramatic structural changes, including an ice-VII-like structural motif at a particle velocity of approximately 1 km/s. The incipient ice VII formation and the calculated Hugoniot curve are in good agreement with experimental results. Moreover, a substantial number of positive and negative ions appear when the nanojet hits the distal side of the nanobubble and the water hammer shock forms. Furthermore, two promising applications of shock-induced nanobubble collapse have been explored. Our simulations of poration in lipid bilayers due to shock-induced collapse of nanobubbles reveal penetration of nanojets into lipid bilayers. The nanojet impact generates shear flow of water on bilayer leaflets and pressure gradients across them, which transiently enhance the bilayer permeability by creating nanopores through which water molecules translocate across the bilayer. The effects of nanobubble size and temperature on the porosity of lipid bilayers are examined. Finally, the shock-induced collapse of CO2-filled nanobubbles in water is investigated. The energetic nanojet and high-pressure water hammer shock formed during and after collapse of the nanobubble trigger mechano-chemical H2O-CO2 reactions, some of which lead to splitting of water molecules. The dominant pathways through which splitting of water molecules occur are identified.

When the world collapses: changed worldview and social reconstruction in a traumatized community

PubMed Central

Biruski, Dinka Corkalo; Ajdukovic, Dean; Stanic, Ajana Löw

2014-01-01

Background Traumatic experience can affect the individual's basic beliefs about the world as a predictable and safe place. One of the cornerstones in recovery from trauma is reestablishment of safety, connectedness, and the shattered schema of a worldview. Objective This study explored the role of negatively changed worldview in the relationship between war-related traumatization and readiness for social reconstruction of intergroup relations in a post-conflict community measured by three processes: intergroup rapprochement, rebuilding trust, and need for apology. It was hypothesized that more traumatized people are less supportive of social reconstruction and that this relationship is mediated by the changed worldview. Method The study included a community random sample of 333 adults in the city of Vukovar, Croatia, that was most devastated during the 1991–1995 war. Six instruments were administered: Stressful Events Scale, Impact of Event Scale-Revised, Changed Worldview Scale, and three scales measuring the post-conflict social reconstruction processes: Intergroup Rapprochement, Intergroup Trust and Need for Apology. Results Mediation analyses showed that the worldview change fully mediated between traumatization and all three aspects of social reconstruction. Conclusions In a population exposed to war traumatization the worldview change mediates post-conflict social recovery of community relations. PMID:25279101

PHYSICAL CHARACTERISTICS AND HEALTH EFFECTS OF AEROSOLS FROM COLLAPSED BUILDINGS

EPA Science Inventory

Airborne pollutants can rise to extreme levels when large buildings fall down. The terrorist attack on New York's World Trade Center (WTC) towers caused the release of an enormous quantity of pulverized building materials and combustion products into the local environment. Partic...

The potential behavioral and economic impacts of widespread HMG-CoA reductase inhibitor (statin) use.

PubMed

Gendle, Mathew H

2016-12-01

Dyslipidemia is a common pathology throughout the industrialized world, and HMG-CoA reductase inhibitors (statins) are often administered to treat elevated lipid levels. Substantial concern has been raised regarding the aggressive clinical lowering of cholesterol, particularly in light of a growing body of research linking low circulating lipid levels with negative behavioral outcomes in both human samples and non-human primate models. In 2009, Goldstein and colleagues tentatively speculated that the greed, impulsiveness, and lack of foresight that lead to the worldwide economic collapse in 2007-2008 could have been caused (in part) by depressed population cholesterol levels resulting from the widespread use of statins by workers in the financial services industry. This paper reviews the literature that links low circulating lipid levels with neurobehavioral dysfunction, develops Goldstein and colleagues' initial speculation into a formal hypothesis, and proposes several specific studies that could rigorously empirically evaluate this hypothesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Search for water and life's building blocks in the universe: A summary

NASA Astrophysics Data System (ADS)

Bergin, Edwin A.

Water and organics need to be supplied to terrestrial worlds like our own to provide the essential compounds required for the origin of life. These molecules form initially during the earliest stages of stellar birth, are supplied by collapse to the planet-forming disk predominantly as ice, and may undergo significant processing during this collapse and within large planetesimals that are heated via radioactive decay. Water and organic carriers can be quite volatile, thus their survival as ices within rocks is not preordained. In this focus meeting our goal is to bring together astronomers, cosmochemists, planetary scientists, chemical physicists, and spectroscopists who each explore individual aspects of this problem. In this summary we discuss some of the main themes that appeared in the meeting. Ultimately, cross-field collaboration is needed to provide greater understanding of the likelihood that terrestrial worlds form with these key compounds readily available on their surfaces - and are hence habitable if present at the right distance from the star.

Formation of collapsed tetragonal phase in EuCo₂As₂ under high pressure.

PubMed

Bishop, Matthew; Uhoya, Walter; Tsoi, Georgiy; Vohra, Yogesh K; Sefat, Athena S; Sales, Brian C

2010-10-27

The structural properties of EuCo₂As₂ have been studied up to 35 GPa, through the use of x-ray diffraction in a diamond anvil cell at a synchrotron source. At ambient conditions, EuCo₂As₂ ) (I4/mmm) has a tetragonal lattice structure with a bulk modulus of 48 ± 4 GPa. With the application of pressure, the a axis exhibits negative compressibility with a concurrent sharp decrease in c-axis length. The anomalous compressibility of the a axis continues until 4.7 GPa, at which point the structure undergoes a second-order phase transition to a collapsed tetragonal (CT) state with a bulk modulus of 111 ± 2 GPa. We found a strong correlation between the ambient pressure volume of 122 parents of superconductors and the corresponding tetragonal to collapsed tetragonal phase transition pressures.

SOCIOECONOMIC CHANGE AND HOMICIDE IN A TRANSITIONAL SOCIETY

PubMed Central

Pridemore, William Alex; Kim, Sang-Weon

2008-01-01

Durkheim argued that rapid social change would produce anomic conditions which, in turn, would lead to increases in criminal and deviant behavior. Russia provides a unique opportunity to test this theory given the large-scale fundamental socioeconomic changes occurring in the nation. Russian homicide rates more than doubled in the years following the dissolution of the Soviet Union and are now among the highest in the world. The pace and effects of the socioeconomic transition vary widely throughout Russia, however, as do rates of and changes in violent crime. In this study, we took advantage of the unique natural experiment of the collapse of the Soviet Union to examine the association between socioeconomic change and homicide. We measured the negative effects of socioeconomic change by creating an index of changes in population size, unemployment, privatization, and foreign investment. Using data from Russian regions (n = 78) and controlling for other structural covariates, regression results indicated that regions that more strongly experienced the negative effects of socioeconomic change were regions where homicide rates increased the most between 1991 and 2000. Further analysis of the individual components of this index revealed that regions with greater increases in (1) unemployment experienced greater increases in homicide rates and (2) privatization experienced smaller increases in homicide rates. PMID:19043617

Thermal dependence of cardiac function in arctic fish: implications of a warming world.

PubMed

Franklin, Craig E; Farrell, Anthony P; Altimiras, Jordi; Axelsson, Michael

2013-11-15

With the Arctic experiencing one of the greatest and most rapid increases in sea temperatures in modern time, predicting how Arctic marine organisms will respond to elevated temperatures has become crucial for conservation biology. Here, we examined the thermal sensitivity of cardiorespiratory performance for three closely related species of sculpins that inhabit the Arctic waters, two of which, Gymnocanthus tricuspis and Myoxocephalus scorpioides, have adapted to a restricted range within the Arctic, whereas the third species, Myoxocephalus scorpius, has a wider distribution. We tested the hypothesis that the fish restricted to Arctic cold waters would show reduced cardiorespiratory scope in response to an increase in temperature, as compared with the more eurythermal M. scorpius. As expected from their biogeography, M. scorpioides and G. tricuspis maximised cardiorespiratory performance at temperatures between 1 and 4°C, whereas M. scorpius maximised performance over a wider range of temperatures (1-10°C). Furthermore, factorial scope for cardiac output collapsed at elevated temperature for the two high-latitude species, negatively impacting their ability to support aerobically driven metabolic processes. Consequently, these results concurred with our hypothesis, suggesting that the sculpin species restricted to the Arctic are likely to be negatively impacted by increases in ocean temperatures.

Estimating structural collapse fragility of generic building typologies using expert judgment

USGS Publications Warehouse

Jaiswal, Kishor; Wald, David J.; Perkins, David M.; Aspinall, Willy P.; Kiremidjian, Anne S.

2014-01-01

The structured expert elicitation process proposed by Cooke (1991), hereafter referred to as Cooke's approach, is applied for the first time in the realm of structural collapse-fragility assessment for selected generic construction types. Cooke's approach works on the principle of objective calibration scoring of judgments couple with hypothesis testing used in classical statistics. The performance-based scoring system reflects the combined measure of an expert's informativeness about variables in the problem are under consideration, and their ability to enumerate, in a statistically accurate way through expressing their true beliefs, the quantitative uncertainties associated with their assessments. We summarize the findings of an expert elicitation workshop in which a dozen earthquake-engineering professionals from around the world were engaged to estimate seismic collapse fragility for generic construction types. Development of seismic collapse fragility-functions was accomplished by combining their judgments using weights derived from Cooke's method. Although substantial effort was needed to elicit the inputs of these experts successfully, we anticipate that the elicitation strategy described here will gain momentum in a wide variety of earthquake seismology and engineering hazard and risk analyses where physical model and data limitations are inherent and objective professional judgment can fill gaps.

Estimating structural collapse fragility of generic building typologies using expert judgment

USGS Publications Warehouse

Jaiswal, Kishor S.; Wald, D.J.; Perkins, D.; Aspinall, W.P.; Kiremidjian, Anne S.; Deodatis, George; Ellingwood, Bruce R.; Frangopol, Dan M.

2014-01-01

The structured expert elicitation process proposed by Cooke (1991), hereafter referred to as Cooke’s approach, is applied for the first time in the realm of structural collapse-fragility assessment for selected generic construction types. Cooke’s approach works on the principle of objective calibration scoring of judgments coupled with hypothesis testing used in classical statistics. The performance-based scoring system reflects the combined measure of an expert’s informativeness about variables in the problem area under consideration, and their ability to enumerate, in a statistically accurate way through expressing their true beliefs, the quantitative uncertainties associated with their assessments. We summarize the findings of an expert elicitation workshop in which a dozen earthquake-engineering professionals from around the world were engaged to estimate seismic collapse fragility for generic construction types. Development of seismic collapse fragility functions was accomplished by combining their judgments using weights derived from Cooke’s method. Although substantial effort was needed to elicit the inputs of these experts successfully, we anticipate that the elicitation strategy described here will gain momentum in a wide variety of earthquake seismology and engineering hazard and risk analyses where physical model and data limitations are inherent and objective professional judgment can fill gaps.

Parametric analysis of lava dome-collapse events and pyroclastic deposits at Shiveluch volcano, Kamchatka, using visible and infrared satellite data

NASA Astrophysics Data System (ADS)

Krippner, Janine B.; Belousov, Alexander B.; Belousova, Marina G.; Ramsey, Michael S.

2018-04-01

For the years 2001 to 2013 of the ongoing eruption of Shiveluch volcano, a combination of different satellite remote sensing data are used to investigate the dome-collapse events and the resulting pyroclastic deposits. Shiveluch volcano in Kamchatka, Russia, is one of the world's most active dome-building volcanoes, which has produced some of the largest known historical block-and-ash flows (BAFs). Globally, quantitative data for deposits resulting from such large and long-lived dome-forming eruptions, especially like those at Shiveluch, are scarce. We use Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) thermal infrared (TIR), shortwave infrared (SWIR), and visible-near infrared (VNIR) data to analyze the dome-collapse scars and BAF deposits that were formed during eruptions and collapse events in 2001, 2004, 2005, 2007, 2009, 2010, and two events in 2013. These events produced flows with runout distances of as far as 19 km from the dome, and with aerial extents of as much as 22.3 km2. Over the 12 years of this period of investigation, there is no trend in deposit area or runout distances of the flows through time. However, two potentially predictive features are apparent in our data set: 1) the largest dome-collapse events occurred when the dome exceeded a relative height (from dome base to top) of 500 m; 2) collapses were preceded by thermal anomalies in six of the cases in which ASTER data were available, although the areal extent of these precursory thermal areas did not generally match the size of the collapse events as indicated by scar area (volumes are available for three collapse events). Linking the deposit distribution to the area, location, and temperature profiles of the dome-collapse scars provides a basis for determining similar future hazards at Shiveluch and at other dome-forming volcanoes. Because of these factors, we suggest that volcanic hazard analysis and mitigation at volcanoes with similar BAF emplacement behavior may be improved with detailed, synoptic studies, especially when it is possible to access and interpret appropriate remote sensing data in near-real time.

Non-singular Brans–Dicke collapse in deformed phase space

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

Rasouli, S.M.M., E-mail: mrasouli@ubi.pt; Centro de Matemática e Aplicações; Physics Group, Qazvin Branch, Islamic Azad University, Qazvin

2016-12-15

We study the collapse process of a homogeneous perfect fluid (in FLRW background) with a barotropic equation of state in Brans–Dicke (BD) theory in the presence of phase space deformation effects. Such a deformation is introduced as a particular type of non-commutativity between phase space coordinates. For the commutative case, it has been shown in the literature (Scheel, 1995), that the dust collapse in BD theory leads to the formation of a spacetime singularity which is covered by an event horizon. In comparison to general relativity (GR), the authors concluded that the final state of black holes in BD theorymore » is identical to the GR case but differs from GR during the dynamical evolution of the collapse process. However, the presence of non-commutative effects influences the dynamics of the collapse scenario and consequently a non-singular evolution is developed in the sense that a bounce emerges at a minimum radius, after which an expanding phase begins. Such a behavior is observed for positive values of the BD coupling parameter. For large positive values of the BD coupling parameter, when non-commutative effects are present, the dynamics of collapse process differs from the GR case. Finally, we show that for negative values of the BD coupling parameter, the singularity is replaced by an oscillatory bounce occurring at a finite time, with the frequency of oscillation and amplitude being damped at late times.« less

Destruction of the World Trade Center Towers. Lessons Learned from an Environmental Health Disaster.

PubMed

Reibman, Joan; Levy-Carrick, Nomi; Miles, Terry; Flynn, Kimberly; Hughes, Catherine; Crane, Michael; Lucchini, Roberto G

2016-05-01

The assault and subsequent collapse of the World Trade Center towers in New York City on September 11, 2001 (9/11), released more than a million tons of debris and dust into the surrounding area, engulfing rescue workers as they rushed to aid those who worked in the towers, and the thousands of nearby civilians and children who were forced to flee. In December 2015, almost 15 years after the attack, and 5 years after first enactment, Congress reauthorized the James Zadroga 9/11 Health and Compensation Act, a law designed to respond to the adverse health effects of the disaster. This reauthorization affords an opportunity to review human inhalation exposure science in relation to the World Trade Center collapse. In this Special Article, we compile observations regarding the collective medical response to the environmental health disaster with a focus on efforts to address the adverse health effects experienced by nearby community members including local residents and workers. We also analyze approaches to understanding the potential for health risk, characterization of hazardous materials, identification of populations at risk, and shortfalls in the medical response on behalf of the local community. Our overarching goal is to communicate lessons learned from the World Trade Center experience that may be applicable to communities affected by future environmental health disasters. The World Trade Center story demonstrates that communities lacking advocacy and preexisting health infrastructures are uniquely vulnerable to health disasters. Medical and public health personnel need to compensate for these vulnerabilities to mitigate long-term illness and suffering.

Destruction of the World Trade Center Towers. Lessons Learned from an Environmental Health Disaster

PubMed Central

Levy-Carrick, Nomi; Miles, Terry; Flynn, Kimberly; Hughes, Catherine; Crane, Michael; Lucchini, Roberto G.

2016-01-01

The assault and subsequent collapse of the World Trade Center towers in New York City on September 11, 2001 (9/11), released more than a million tons of debris and dust into the surrounding area, engulfing rescue workers as they rushed to aid those who worked in the towers, and the thousands of nearby civilians and children who were forced to flee. In December 2015, almost 15 years after the attack, and 5 years after first enactment, Congress reauthorized the James Zadroga 9/11 Health and Compensation Act, a law designed to respond to the adverse health effects of the disaster. This reauthorization affords an opportunity to review human inhalation exposure science in relation to the World Trade Center collapse. In this Special Article, we compile observations regarding the collective medical response to the environmental health disaster with a focus on efforts to address the adverse health effects experienced by nearby community members including local residents and workers. We also analyze approaches to understanding the potential for health risk, characterization of hazardous materials, identification of populations at risk, and shortfalls in the medical response on behalf of the local community. Our overarching goal is to communicate lessons learned from the World Trade Center experience that may be applicable to communities affected by future environmental health disasters. The World Trade Center story demonstrates that communities lacking advocacy and preexisting health infrastructures are uniquely vulnerable to health disasters. Medical and public health personnel need to compensate for these vulnerabilities to mitigate long-term illness and suffering. PMID:26872108

ENVIRONMENTAL RESEARCH IN RESPONSE TO 9/11 AND HOMELAND SECURITY

EPA Science Inventory

The terrorist attacks on September 11, 2001 resulted in a disaster unlike any other on U.S. soil. The collapse of the World Trade Center (WTC) towers and the underground fires that burned for months required the efforts of numerous Federal, State and local agencies as well as uni...

The Political Geography of Europe: 1900-2000 A.D.

ERIC Educational Resources Information Center

Blouet, Brian W.

1996-01-01

Traces the often chaotic restructuring of European national boundaries from before World War I to after the collapse of the Soviet Union. Offers a concise and interesting overview of the political, economic, and military events that shaped modern Europe. Includes seven detailed maps showing shifting boundaries and alliances. (MJP)

MODELING AIR POLLUTION FROM THE COLLAPSE OF THE WORLD TRADE CENTER AND ASSESSING THE POTENTIAL IMPACTS ON HUMAN EXPOSURE

EPA Science Inventory

The US EPA National Exposure Research Laboratory (NERL) and the Environmental and Occupational Health Sciences Institute (EOHSI) have been working together under a University Partnership Agreement to develop improved methods for human exposure modeling. This partnership was ongo...

Parametric interaction and spatial collapse of beam-driven Langmuir waves in the solar wind. [upstream of Jupiter bow shock

NASA Technical Reports Server (NTRS)

Gurnett, D. A.; Maggs, J. E.; Gallagher, D. L.; Kurth, W. S.; Scarf, F. L.

1981-01-01

Observations are presented of the parametric decay and spatial collapse of Langmuir waves driven by an electron beam streaming into the solar wind from the Jovian bow shock. Long wavelength Langmuir waves upstream of the bow shock are effectively converted into short wavelength waves no longer in resonance with the beam. The conversion is shown to be the result of a nonlinear interaction involving the beam-driven pump, a sideband emission, and a low level of ion-acoustic turbulence. The beam-driven Langmuir wave emission breaks up into a complex sideband structure with both positive and negative Doppler shifts. In some cases, the sideband emission consists of isolated wave packets with very short duration bursts, which are very intense and are thought to consist of envelope solitons which have collapsed to spatial scales of only a few Debye lengths.

Single-World Theory of the Extended Wigner's Friend Experiment

NASA Astrophysics Data System (ADS)

Sudbery, Anthony

2017-05-01

Frauchiger and Renner have recently claimed to prove that "Single-world interpretations of quantum theory cannot be self-consistent". This is contradicted by a construction due to Bell, inspired by Bohmian mechanics, which shows that any quantum system can be modelled in such a way that there is only one "world" at any time, but the predictions of quantum theory are reproduced. This Bell-Bohmian theory is applied to the experiment proposed by Frauchiger and Renner, and their argument is critically examined. It is concluded that it is their version of "standard quantum theory", incorporating state vector collapse upon measurement, that is not self-consistent.

Collapsing health care in Serbia and Montenegro.

PubMed Central

Black, M E

1993-01-01

Serbia and Montenegro together form the Federal Republic of Yugoslavia. As well as the Serb majority this includes the mixed province of Vojvodina, the mainly Albanian population in Kosovo, and the large Muslim minority in Sandzak. Since the start of war in 1991 the attention and sympathies of the world have focused on Bosnia and Croatia. The United Nations imposed economic sanctions on the federal republic in 1992, although in theory medical supplies and aid are exempt. The economy has now collapsed under the triple burden of war, loss of trade between the republics, and UN sanctions. A major public health catastrophe is unfolding in the federal republic. Images p1135-a p1136-a PMID:8251816

Sequential megafaunal collapse in the North Pacific Ocean: An ongoing legacy of industrial whaling?

USGS Publications Warehouse

Springer, A.M.; Estes, J.A.; Van Vliet, Gus B.; Williams, T.M.; Doak, D.F.; Danner, E.M.; Forney, K.A.; Pfister, B.

2003-01-01

Populations of seals, sea lions, and sea otters have sequentially collapsed over large areas of the northern North Pacific Ocean and southern Bering Sea during the last several decades. A bottom-up nutritional limitation mechanism induced by physical oceanographic change or competition with fisheries was long thought to be largely responsible for these declines. The current weight of evidence is more consistent with top-down forcing. Increased predation by killer whales probably drove the sea otter collapse and may have been responsible for the earlier pinniped declines as well. We propose that decimation of the great whales by post-World War II industrial whaling caused the great whales' foremost natural predators, killer whales, to begin feeding more intensively on the smaller marine mammals, thus "fishing-down" this element of the marine food web. The timing of these events, information on the abundance, diet, and foraging behavior of both predators and prey, and feasibility analyses based on demographic and energetic modeling are all consistent with this hypothesis.

Sequential megafaunal collapse in the North Pacific Ocean: An ongoing legacy of industrial whaling?

PubMed Central

Springer, A. M.; Estes, J. A.; van Vliet, G. B.; Williams, T. M.; Doak, D. F.; Danner, E. M.; Forney, K. A.; Pfister, B.

2003-01-01

Populations of seals, sea lions, and sea otters have sequentially collapsed over large areas of the northern North Pacific Ocean and southern Bering Sea during the last several decades. A bottom-up nutritional limitation mechanism induced by physical oceanographic change or competition with fisheries was long thought to be largely responsible for these declines. The current weight of evidence is more consistent with top-down forcing. Increased predation by killer whales probably drove the sea otter collapse and may have been responsible for the earlier pinniped declines as well. We propose that decimation of the great whales by post-World War II industrial whaling caused the great whales' foremost natural predators, killer whales, to begin feeding more intensively on the smaller marine mammals, thus “fishing-down” this element of the marine food web. The timing of these events, information on the abundance, diet, and foraging behavior of both predators and prey, and feasibility analyses based on demographic and energetic modeling are all consistent with this hypothesis. PMID:14526101

Negative life events and life satisfaction in university students: Belief in a just world as a mediator and moderator.

PubMed

Tian, Xunlong

2016-11-01

A cross-sectional study was conducted to explore the role of belief in a just world between negative life events and life satisfaction. The results revealed that two dimensions of belief in a just world played partial mediating roles between negative life events and life satisfaction. Moreover, belief in a just world was also a moderator between negative life events and life satisfaction that mitigates the adverse effects of negative life events. In conclusion, these results suggest that belief in a just world could be both a mediator and a moderator between negative life events and life satisfaction.

Holistic screening of collapsing honey bee colonies in Spain: a case study.

PubMed

Cepero, Almudena; Ravoet, Jorgen; Gómez-Moracho, Tamara; Bernal, José Luis; Del Nozal, Maria J; Bartolomé, Carolina; Maside, Xulio; Meana, Aránzazu; González-Porto, Amelia V; de Graaf, Dirk C; Martín-Hernández, Raquel; Higes, Mariano

2014-09-15

Here we present a holistic screening of collapsing colonies from three professional apiaries in Spain. Colonies with typical honey bee depopulation symptoms were selected for multiple possible factors to reveal the causes of collapse. Omnipresent were Nosema ceranae and Lake Sinai Virus. Moderate prevalences were found for Black Queen Cell Virus and trypanosomatids, whereas Deformed Wing Virus, Aphid Lethal Paralysis Virus strain Brookings and neogregarines were rarely detected. Other viruses, Nosema apis, Acarapis woodi and Varroa destructor were not detected. Palinologic study of pollen demonstrated that all colonies were foraging on wild vegetation. Consequently, the pesticide residue analysis was negative for neonicotinoids. The genetic analysis of trypanosomatids GAPDH gene, showed that there is a large genetic distance between Crithidia mellificae ATCC30254, an authenticated cell strain since 1974, and the rest of the presumed C. mellificae sequences obtained in our study or published. This means that the latter group corresponds to a highly differentiated taxon that should be renamed accordingly. The results of this study demonstrate that the drivers of colony collapse may differ between geographic regions with different environmental conditions, or with different beekeeping and agricultural practices. The role of other pathogens in colony collapse has to bee studied in future, especially trypanosomatids and neogregarines. Beside their pathological effect on honey bees, classification and taxonomy of these protozoan parasites should also be clarified.

When You Wish upon a Star It Makes a Difference Who You Are: Children's Culture and the Wonderful World of Disney.

ERIC Educational Resources Information Center

Giroux, Henry A.

1995-01-01

The boundaries between entertainment, education, and commercialization collapse through Disney's reach into diverse spheres of everyday life. Disney's "innocence" is a promotional mask covering its aggressive marketing techniques and influence in transforming children into active consumers. Although Disney's films are joyous and…

Whither the Heavy Forces in the Post-Containment World

DTIC Science & Technology

1990-04-20

Japan (50,500), Philippines (17,300) and Panama (10,700).1 The European forces will be reduced by the Conventional Forces in Europe (CFE) treaty,2 by a... tardy in responding. This would be particularly damaging if the integrity of some major oil fields were at stake or if the collapse of a friendly

PERSISTENT ORGANIC POLLUTANTS IN DUSTS THAT SETTLED AT INDOOR AND OUTDOOR LOCATIONS IN LOWER MANHATTAN AFTER 11 SEPTEMBER, 2001

EPA Science Inventory

During the initial days that followed the explosion and collapse of the World Trade Center (WTC) on September 11th, 2001, fourteen bulk samples of settled dusts were collected at locations surrounding the epicenter of the disaster, and analyzed for persistent organic pollutants, ...

Black Elite: The New Market for Highly Educated Black Americans.

ERIC Educational Resources Information Center

Freeman, Richard B.

This examination of the collapse in traditional discriminatory patterns in the market for highly qualified black Americans documents the World War II gain of college trained and related high level black workers, investigates the response of black college students and qualified personnel to the new market setting, and explores the factors that…

Building Collaboration through Project-Based Theater Design

ERIC Educational Resources Information Center

Basarab, Heather

2012-01-01

With the economic collapse of 2008, there has been a dramatic increase in government emphasis on the value of science and technology-based study in the nation's high schools as a means for the United States to remain competitive in the world economic market. Financial, political and societal support for the hard sciences, coupled with…

Viscous-enstrophy scaling law for Navier-Stokes reconnection

NASA Astrophysics Data System (ADS)

Kerr, Robert M.

2017-11-01

Simulations of perturbed, helical trefoil vortex knots and anti-parallel vortices find ν-independent collapse of temporally scaled (√{ ν} Z) - 1 / 2, Z enstrophy, between when the loops first touch at tΓ, and when reconnection ends at tx for the viscosity ν varying by 256. Due to mathematical bounds upon higher-order norms, this collapse requires that the domain increase as ν decreases, possibly to allow large-scale negative helicity to grow as compensation for small-scale positive helicity and enstrophy growth. This mechanism could be a step towards explaining how smooth solutions of the Navier-Stokes can generate finite-energy dissipation in a finite time as ν -> 0 .

New Insights into Passive Margin Development from a Global Deep Seismic Reflection Dataset

NASA Astrophysics Data System (ADS)

Bellingham, Paul; Pindell, James; Graham, Rod; Horn, Brian

2014-05-01

The kinematic and dynamic evolution of the world's passive margins is still poorly understood. Yet the need to replace reserves, a high oil price and advances in drilling technology have pushed the international oil and gas industry to explore in the deep and ultra-deep waters of the continental margins. To support this exploration and help understand these margins, ION-GXT has acquired, processed and interpreted BasinSPAN surveys across many of the world's passive margins. Observations from these data lead us to consider the modes of subsidence and uplift at both volcanic and non-volcanic margins. At non-volcanic margins, it appears that frequently much of the subsidence post-dates major rifting and is not thermal in origin. Rather the subsidence is associated with extensional displacement on a major fault or shear zone running at least as deep as the continental Moho. We believe that the subsidence is structural and is probably associated with the pinching out (boudinage) of the Lower Crust so that the Upper crust effectively collapses onto the mantle. Eventually this will lead to the exhumation of the sub-continental mantle at the sea bed. Volcanic margins present more complex challenges both in terms of imaging and interpretation. The addition of volcanic and plutonic material into the system and dynamic effects all impact subsidence and uplift. However, we will show some fundamental observations regarding the kinematic development of volcanic margins and especially SDRs which demonstate that the process of collapse and the development of shear zones within and below the crust are also in existence at this type of margin. A model is presented of 'magma welds' whereby packages of SDRs collapse onto an emerging sub-crustal shear zone and it is this collapse which creates the commonly observed SDR geometry. Examples will be shown from East India, Newfoundland, Brazil, Argentina and the Gulf of Mexico.

Does the World Health Organization histological classification predict outcomes after thymomectomy? Results of a multicentre study on 750 patients.

PubMed

Guerrera, Francesco; Rendina, Erino Angelo; Venuta, Federico; Margaritora, Stefano; Ciccone, Anna Maria; Novellis, Pierluigi; Novero, Domenico; Anile, Marco; Bora, Giulia; Rena, Ottavio; Casadio, Caterina; Mussi, Alfredo; Evangelista, Andrea; Ruffini, Enrico; Lucchi, Marco; Filosso, Pier Luigi

2015-07-01

The World Health Organization (WHO) thymoma histological classification clinical value remains a controversy. In this study, we evaluated its prognostic significance in patients with thymoma treated with radical intent. Six high-volume Italian Thoracic Surgery Institutions collaborated with their own retrospective anonymized datasets. Demographic, clinical, pathological and treatment data were examined. A WHO histological classification (WHO-HC) collapsed scheme (A/AB and B1/B2 types merged) was proposed and compared with the traditional one. Predictors of survival were assessed using a Cox model with shared frailty. Competing-risk regression models were performed to identify the association between individual factors and freedom from recurrence. Between 1990 and 2011, 750 thymomas were operated on in participating centres. Myasthenia gravis was observed in 363 (48%) patients. A complete resection was achieved in 676 (91%) cases. One hundred and nine patients (15%) had a WHO-HC A type, 166 (22%) AB, 179 (24%) B1, 158 (21%) B2 and 135 (18%) B3. The rate of 5-year OS and cumulative incidence of recurrence for all cases was 91% and 0.11, respectively. Five-year survival rates by WHO-HC in the collapsed scheme were A/AB 93%, early-B 90% and advanced-B 85%. Masaoka stage only was demonstrated to be an independent predictor for survival and recurrence. The WHO-collapsed scheme showed a trend in influencing recurrence overall survival development (hazard ratio: 1.32; P = 0.16). Our results show evidence of lack of significance by WHO-HC in influencing prognosis, even though the proposed collapsed scheme revealed a fair stratification of risk to relapses and better correlation with patients' clinical characteristics. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Volume-based characterization of postocclusion surge.

PubMed

Zacharias, Jaime; Zacharias, Sergio

2005-10-01

To propose an alternative method to characterize postocclusion surge using a collapsible artificial anterior chamber to replace the currently used rigid anterior chamber model. Fundación Oftamológica Los Andes, Santiago, Chile. The distal end of a phacoemulsification handpiece was placed inside a compliant artificial anterior chamber. Digital recordings of chamber pressure, chamber volume, inflow, and outflow were performed during occlusion break of the phacoemulsification tip. The occlusion break profile of 2 different consoles was compared. Occlusion break while using a rigid anterior chamber model produced a simultaneous increase of chamber inflow and outflow. In the rigid chamber model, pressure decreased sharply, reaching negative pressure values. Alternatively, with the collapsible chamber model, a delay was observed in the inflow that occurs to compensate the outflow surge. Also, the chamber pressure drop was smaller in magnitude, never undershooting below atmospheric pressure into negative values. Using 500 mm Hg as vacuum limit, the Infiniti System (Alcon) performed better that the Legacy (Alcon), showing an 18% reduction in peak volume variation. The collapsible anterior chamber model provides a more realistic representation of the postocclusion surge events that occur in the real eye during cataract surgery. Peak volume fluctuation (mL), half volume recovery time(s), and volume fluctuation integral value (mL x s) are proposed as realistic indicators to characterize the postocclusion surge performance. These indicators show that the Infiniti System has a better postocclusion surge behavior than the Legacy System.

Collapse, environment, and society

PubMed Central

2012-01-01

Historical collapse of ancient states poses intriguing social-ecological questions, as well as potential applications to global change and contemporary strategies for sustainability. Five Old World case studies are developed to identify interactive inputs, triggers, and feedbacks in devolution. Collapse is multicausal and rarely abrupt. Political simplification undermines traditional structures of authority to favor militarization, whereas disintegration is preconditioned or triggered by acute stress (insecurity, environmental or economic crises, famine), with breakdown accompanied or followed by demographic decline. Undue attention to stressors risks underestimating the intricate interplay of environmental, political, and sociocultural resilience in limiting the damages of collapse or in facilitating reconstruction. The conceptual model emphasizes resilience, as well as the historical roles of leaders, elites, and ideology. However, a historical model cannot simply be applied to contemporary problems of sustainability without adjustment for cumulative information and increasing possibilities for popular participation. Between the 14th and 18th centuries, Western Europe responded to environmental crises by innovation and intensification; such modernization was decentralized, protracted, flexible, and broadly based. Much of the current alarmist literature that claims to draw from historical experience is poorly focused, simplistic, and unhelpful. It fails to appreciate that resilience and readaptation depend on identified options, improved understanding, cultural solidarity, enlightened leadership, and opportunities for participation and fresh ideas. PMID:22371579

Abrupt climatic changes as triggering mechanisms of massive volcanic collapses: examples from Mexico (Invited)

NASA Astrophysics Data System (ADS)

Capra, L.

2010-12-01

Climate changes have been considered to be a triggering mechanism for large magmatic eruptions. However they can also trigger volcanic collapses, phenomena that cause the destruction of the entire sector of a volcano, including its summit. During the past 30 ka, major volcanic collapses occurred just after main glacial peaks that ended with a rapid deglaciation. Glacial debuttressing, load discharge and fluid circulation coupled with the post-glacial increase of humidity and heavy rains can activate the failure of unstable edifices. Looking at the synchronicity of the maximum glaciations during the late Pleistocene and Holocene in the northern and southern hemispheres it is evident that several volcanic collapses are absent during a glacial climax, but start immediately after it during a period of rapid retreat. Several examples can be detected around the world and Mexico is not an exception. The 28 ka Nevado de Toluca volcanic collapse occurred during an intraglacial stage, under humid conditions as evidenced by paleoclimatic studies on lacustrine sediments of the area. The debris avalanche deposit associated to this event clearly shows evidence of a large amount of water into the mass previous to the failure that enhanced its mobility. It also contains peculiar, plastically deformed, m-sized fragment of lacustrine sediments eroded from glacial berms. The 17 ka BP collapse of the Colima Volcano corresponds to the initial stage of glacial retreat in Mexico after the Last Glacial Maximum (22-17.5ka). Also in this case the depositional sequence reflects high humidity conditions with voluminous debris flow containing a large amount logs left by pine trees. The occurrence of cohesive debris flows originating from the failure of a volcanic edifice can also reflect the climatic conditions, indicating important hydrothermal alteration and fluid circulation from ice-melting at an ice-capped volcano, as observed for example at the Pico de Orizaba volcano for the Tetelzingo lahar, which collapse occurred after the Terminal Glacial (15-11 ka). Furthermore, significant global warming can be responsible for the collapse of ice-capped unstable volcanoes, an unpredictable hazard that in few minutes can bury inhabited areas.

Fistula Isolation and the Use of Negative Pressure to Promote Wound Healing: A Case Study.

PubMed

Reider, Kersten E

A 54-year-old morbidly obese woman with a small bowel obstruction and large ventral hernia was admitted to hospital. She underwent an exploratory laparotomy, lysis of adhesions, and ventral hernia repair with mesh placement. She subsequently developed an enteroatmospheric fistula; several months of hospital care was required to effectively manage the wound and contain effluent from the fistula. Several approaches were used to manage output from the fistula during her hospital course. She was initially discharged to a skilled nursing facility where a fistula management pouch was used for several months to encompass the wound and contain effluent, but this method ultimately proved ineffective. The fistula was then isolated using a collapsible enteroatmospheric fistula isolation device and an ostomy appliance to contain effluent. The application of the collapsible enteroatmospheric fistula isolation and effluent containment devices in conjunction with negative-pressure wound therapy produced positive patient outcomes; it improved patient satisfaction with fistula management, promoted wound healing, and diminished cost.

GENASIS: General Astrophysical Simulation System. I. Refinable Mesh and Nonrelativistic Hydrodynamics

NASA Astrophysics Data System (ADS)

Cardall, Christian Y.; Budiardja, Reuben D.; Endeve, Eirik; Mezzacappa, Anthony

2014-02-01

GenASiS (General Astrophysical Simulation System) is a new code being developed initially and primarily, though by no means exclusively, for the simulation of core-collapse supernovae on the world's leading capability supercomputers. This paper—the first in a series—demonstrates a centrally refined coordinate patch suitable for gravitational collapse and documents methods for compressible nonrelativistic hydrodynamics. We benchmark the hydrodynamics capabilities of GenASiS against many standard test problems; the results illustrate the basic competence of our implementation, demonstrate the strengths and limitations of the HLLC relative to the HLL Riemann solver in a number of interesting cases, and provide preliminary indications of the code's ability to scale and to function with cell-by-cell fixed-mesh refinement.

29 CFR 1915.1001 - Asbestos.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ACM from straight runs of piping and elbows and other connections with the following specifications... or other device used to prevent collapse of bag during removal shall run continually during the... pressure glove box systems. Negative pressure glove boxes may be used to remove ACM or PACM from pipe runs...

29 CFR 1915.1001 - Asbestos.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ACM from straight runs of piping and elbows and other connections with the following specifications... or other device used to prevent collapse of bag during removal shall run continually during the... pressure glove box systems. Negative pressure glove boxes may be used to remove ACM or PACM from pipe runs...

29 CFR 1915.1001 - Asbestos.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ACM from straight runs of piping and elbows and other connections with the following specifications... or other device used to prevent collapse of bag during removal shall run continually during the... pressure glove box systems. Negative pressure glove boxes may be used to remove ACM or PACM from pipe runs...

29 CFR 1915.1001 - Asbestos.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ACM from straight runs of piping and elbows and other connections with the following specifications... or other device used to prevent collapse of bag during removal shall run continually during the... pressure glove box systems. Negative pressure glove boxes may be used to remove ACM or PACM from pipe runs...

29 CFR 1915.1001 - Asbestos.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ACM from straight runs of piping and elbows and other connections with the following specifications... or other device used to prevent collapse of bag during removal shall run continually during the... pressure glove box systems. Negative pressure glove boxes may be used to remove ACM or PACM from pipe runs...

Tourism's collapse puts Gambian women at risk.

PubMed

Coker, M S

1995-06-01

Despite efforts of the Gambian government, which established a ministry in 1981 that would tackle gender issues, improve women's health, and promote empowerment, women are underrepresented in government and business, and 84% are illiterate. Child mortality is among the highest in Africa; 134 children per 1000 die before their fifth birthday. In the mid-1980s austerity measures adopted by the World Bank and IMF left the ministry without funds. Rice and vegetable production, the main source of income for women, fell in the 1990s. In 1994, paddy production dropped 23% from the previous year; this was due to a lack of technical and financial assistance. The collapse of tourism with Capt. Yahya Jammeh's seizure of power has put prostitutes catering to tourists out of work, but women who have lost jobs in the hotel industry may be pushed into local prostitution to survive. The impact of this on the HIV/AIDS epidemic is unclear. Although Gambia is one of the world's most aid-dependent countries (more than a quarter of the GNP before the coup), corruption and mismanagement in the nongovernmental sector is widespread. The director of the Women in Development Programme, a $15m World Bank project, was forced to resign over allegations of fraud. The political process sidelines women; only village chiefs, who are traditionally men, are allowed to vote when new heads are elected.

Scientific triumphalism and learning from facts: bacteriology and the "Spanish flu" challenge of 1918.

PubMed

Tognotti, Eugenia

2003-04-01

The devastating influenza pandemic known as 'Spanish flu', which killed at least 20 million people all over the world in 1918, was responsible for the first bitter blow inflicted on triumphant bacteriology, fortified by the series of resounding successes achieved in identifying the pathogenic agents of terrible diseases such as anthrax, cholera, tuberculosis, plague, and syphilis. Over-confidence and the idea, born of the Pasteur revolution, that every infectious disease was caused by a bacterium, had led the scientific community to accept the theory put forward by the German bacteriologist, Richard Pfeiffer, who, in 1892, believed he had identified the pathogenic influenza agent in a bacterium, Haemophilus influenzae. But, while the most appalling epidemic ever to sweep through the world since the 'Black Death' of the 1300s was still raging, the scientific community had to admit that influenza originated not from a microbe, but from a virus. This article aims to reconstruct the enlightening and little-known cultured/scientific events and issues of the dramatic crisis that bacteriology experienced in the autumn of 1918, with the consequent simultaneous collapse of both the 'Pfeiffer doctrine' on the microbial origin of influenza and the illusion of a world free of infectious diseases. This was an illusion destined to surface again at the end of the century and collapse with the advent of AIDS.

PERSISTENT ORGANIC POLLUTANTS IN DUSTS THAT SETTLED AT INDOOR AND OUTDOOR LOCATIONS IN LOWER MANHATTAN AFTER 11 SEPTEMBER 2001

EPA Science Inventory

The explosion and collapse of the World Trade Center (WTC) was a catastrophic event that produced an aerosol impacting many workers, residents and commuters during the first few days after September 11th, 2001. During the initial days that followed, fourteen bulk samples of the...

The Economics of Government and the Fall of Rome

ERIC Educational Resources Information Center

Ferrarini, Tawni Hunt

2013-01-01

Most world history books feature the successes of the Roman Empire during the first and second centuries. During the third and fourth centuries, they turn to the events leading up to the empire's collapse. Explanations of the Roman Empire's decline and fall often cite external military threats, governmental failure and instability,…

Young People in an Economic Downturn. Longitudinal Surveys of Australian Youth. Briefing Paper 23

ERIC Educational Resources Information Center

Anlezark, Alison

2011-01-01

Following the collapse of the US investment bank Lehmann Brothers in September 2008, the world economy began a downward spiral, with many countries falling into recession. Australia experienced significant stock market losses and unemployment rates began to climb. This briefing paper considers how young people fared in previous downturns and…

The Battle for the History Books: Who Won the Cold War?

ERIC Educational Resources Information Center

Meyerson, Adam

1990-01-01

Discusses liberal and conservative foreign policy contributions to the end of the Cold War, as marked by the rapid liberalization of Eastern Europe and the Soviet Union. Emphasizes that the collapse of the Soviet empire occurred at the end of a decade of sustained conservative government in every major country of the Western world. (FMW)

KSC-2014-3810

NASA Image and Video Library

2014-09-11

Cape Canaveral, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, the American flag is at half-mast after a ceremony commemorating the 13th anniversary of 9/11 that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Photo credit: Jim Grossmann

KSC-2014-3804

NASA Image and Video Library

2014-09-11

Cape Canaveral, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel pause for a moment of silence during a ceremony commemorating the 13th anniversary of 9/11 at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Photo credit: Jim Grossmann

KSC-2014-3803

NASA Image and Video Library

2014-09-11

Cape Canaveral, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel pause for a moment of silence during a ceremony commemorating the 13th anniversary of 9/11 at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Photo credit: Jim Grossmann

Mechanical properties of gypsum board at elevated temperatures

Treesearch

S.M. Cramer; O.M. Friday; R.H. White; G. Sriprutkiat

2003-01-01

Gypsum board is a common fire barrier used in house and general building construction. Recently, evaluation of the collapses of the World Trade Center Towers highlighted the potential role and failure of gypsum board in containing the fires and resisting damage. The use of gypsum board as primary fire protection of light-flame wood or steel construction is ubiquitous....

Acute High-level Exposure to WTC Particles Alters Expression of Genes Associated with Oxidative Stress and Immune Function in the Lung

EPA Science Inventory

Abstract First responders (FR) present at Ground Zero in the first 72 h after the World Trade Center (WTC) collapsed have progressively exhibited significant respiratory injuries. The few toxicology studies performed to date evaluated effects from just fine(< 2.5 um) WTC dusts; n...

Will Graduating Year Accountancy Students Cheat in Examination? A Malaysian Case

ERIC Educational Resources Information Center

Abu Bakar, Nur Barizah; Ismail, Suhaiza; Mamat, Suaniza

2010-01-01

Due to a series of high profile accounting scandals and corporate collapses such as Enron, World.Com and Andersen, ethical conduct has been widely recognized as a crucial element in accounting profession and education. The growing concern over the ethics of professionals has also called for more academic research into this critical area. Our study…

Biomonitoring of chemical exposure among New York City firefighters responding to the World Trade Center fire and collapse.

PubMed

Edelman, Philip; Osterloh, John; Pirkle, James; Caudill, Sam P; Grainger, James; Jones, Robert; Blount, Ben; Calafat, Antonia; Turner, Wayman; Feldman, Debra; Baron, Sherry; Bernard, Bruce; Lushniak, Boris D; Kelly, Kerry; Prezant, David

2003-12-01

The collapse of the World Trade Center (WTC) on 11 September 2001 exposed New York City firefighters to smoke and dust of unprecedented magnitude and duration. The chemicals and the concentrations produced from any fire are difficult to predict, but estimates of internal dose exposures can be assessed by the biological monitoring of blood and urine. We analyzed blood and urine specimens obtained from 321 firefighters responding to the WTC fires and collapse for 110 potentially fire-related chemicals. Controls consisted of 47 firefighters not present at the WTC. Sampling occurred 3 weeks after 11 September, while fires were still burning. When reference or background ranges were available, most chemical concentrations were found to be generally low and not outside these ranges. Compared with controls, the exposed firefighters showed significant differences in adjusted geometric means for six of the chemicals and significantly greater detection rates for an additional three. Arrival time was a significant predictor variable for four chemicals. Special Operations Command firefighters (n = 95), compared with other responding WTC firefighters (n = 226), had differences in concentrations or detection rate for 14 of the chemicals. Values for the Special Operations Command firefighters were also significantly different from the control group values for these same chemicals and for two additional chemicals. Generally, the chemical concentrations in the other firefighter group were not different from those of controls. Biomonitoring was used to characterize firefighter exposure at the WTC disaster. Although some of the chemicals analyzed showed statistically significant differences, these differences were generally small.

Naked singularities as particle accelerators. II

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

Patil, Mandar; Joshi, Pankaj S.; Malafarina, Daniele

We generalize here our earlier results on particle acceleration by naked singularities. We showed recently [M. Patil and P. S. Joshi, Phys. Rev. D 82, 104049 (2010).] that the naked singularities that form due to the gravitational collapse of massive stars provide a suitable environment where particles could get accelerated and collide at arbitrarily high center-of-mass energies. However, we focused there only on the spherically symmetric gravitational collapse models, which were also assumed to be self-similar. In this paper, we broaden and generalize the result to all gravitational collapse models leading to the formation of a naked singularity as themore » final state of collapse, evolving from a regular initial data, without making any prior restrictive assumptions about the spacetime symmetries such as above. We show that, when the particles interact and collide near the Cauchy horizon, the energy of collision in the center-of-mass frame will be arbitrarily high, thus offering a window to the Planck scale physics. We also consider the issue of various possible physical mechanisms of generation of such very high-energy particles from the vicinity of naked singularity. We then construct a model of gravitational collapse to a timelike naked singularity to demonstrate the working of these ideas, where the pressure is allowed to be negative, but the energy conditions are respected. We show that a finite amount of mass-energy density has to be necessarily radiated away from the vicinity of the naked singularity as the collapse evolves. Therefore, the nature of naked singularities, both at the classical and quantum level, could play an important role in the process of particle acceleration, explaining the occurrence of highly energetic outgoing particles in the vicinity of the Cauchy horizon that participate in extreme high-energy collisions.« less

Scanning the parameter space of collapsing rotating thin shells

NASA Astrophysics Data System (ADS)

Rocha, Jorge V.; Santarelli, Raphael

2018-06-01

We present results of a comprehensive study of collapsing and bouncing thin shells with rotation, framing it in the context of the weak cosmic censorship conjecture. The analysis is based on a formalism developed specifically for higher odd dimensions that is able to describe the dynamics of collapsing rotating shells exactly. We analyse and classify a plethora of shell trajectories in asymptotically flat spacetimes. The parameters varied include the shell’s mass and angular momentum, its radial velocity at infinity, the (linear) equation-of-state parameter and the spacetime dimensionality. We find that plunges of rotating shells into black holes never produce naked singularities, as long as the matter shell obeys the weak energy condition, and so respects cosmic censorship. This applies to collapses of dust shells starting from rest or with a finite velocity at infinity. Not even shells with a negative isotropic pressure component (i.e. tension) lead to the formation of naked singularities, as long as the weak energy condition is satisfied. Endowing the shells with a positive isotropic pressure component allows for the existence of bouncing trajectories satisfying the dominant energy condition and fully contained outside rotating black holes. Otherwise any turning point occurs always inside the horizon. These results are based on strong numerical evidence from scans of numerous sections in the large parameter space available to these collapsing shells. The generalisation of the radial equation of motion to a polytropic equation-of-state for the matter shell is also included in an appendix.

The challenge for Cuba.

PubMed Central

Claudio, L

1999-01-01

The restrictions of a U.S. trade embargo and the collapse of the Soviet Union marked the beginning of a period of extreme economic hardship in Cuba. Economic adversity has had tremendous effects, both positive and negative, on all aspects of life on the Island, including environmental and public health. PMID:10210701

All together now: Analogies between chimera state collapses and epileptic seizures

NASA Astrophysics Data System (ADS)

Andrzejak, Ralph G.; Rummel, Christian; Mormann, Florian; Schindler, Kaspar

2016-03-01

Conceptually and structurally simple mathematical models of coupled oscillator networks can show a rich variety of complex dynamics, providing fundamental insights into many real-world phenomena. A recent and not yet fully understood example is the collapse of coexisting synchronous and asynchronous oscillations into a globally synchronous motion found in networks of identical oscillators. Here we show that this sudden collapse is promoted by a further decrease of synchronization, rather than by critically high synchronization. This strikingly counterintuitive mechanism can be found also in nature, as we demonstrate on epileptic seizures in humans. Analyzing spatiotemporal correlation profiles derived from intracranial electroencephalographic recordings (EEG) of seizures in epilepsy patients, we found a pronounced decrease of correlation at the seizure onsets. Applying our findings in a closed-loop control scheme to models of coupled oscillators in chimera states, we succeed in both provoking and preventing outbreaks of global synchronization. Our findings not only advance the understanding of networks of coupled dynamics but can open new ways to control them, thus offering a vast range of potential new applications.

Jim Peters' collapse in the 1954 Vancouver Empire Games marathon.

PubMed

Noakes, Tim; Mekler, Jackie; Pedoe, Dan Tunstall

2008-08-01

On 7 August 1954, the world 42 km marathon record holder, Jim Peters, collapsed repeatedly during the final 385 metres of the British Empire and Commonwealth Games marathon held in Vancouver, Canada. It has been assumed that Peters collapsed from heatstroke because he ran too fast and did not drink during the race, which was held in windless, cloudless conditions with a dry-bulb temperature of 28 degrees C. Hospital records made available to us indicate that Peters might not have suffered from exertional heatstroke, which classically produces a rectal temperature > 42 degrees C, cerebral effects and, usually, a fatal outcome without vigorous active cooling. Although Peters was unconscious on admission to hospital approximately 60 minutes after he was removed from the race, his rectal temperature was 39.4 degrees C and he recovered fully, even though he was managed conservatively and not actively cooled. We propose that Peters' collapse was more likely due to a combination of hyperthermia-induced fatigue which caused him to stop running; exercise-associated postural hypotension as a result of a low peripheral vascular resistance immediately he stopped running; and combined cerebral effects of hyperthermia, hypertonic hypernatraemia associated with dehydration, and perhaps undiagnosed hypoglycaemia. But none of these conditions should cause prolonged unconsciousness, raising the possibility that Peters might have suffered from a transient encephalopathy, the exact nature of which is not understood.

a Uav Based 3-D Positioning Framework for Detecting Locations of Buried Persons in Collapsed Disaster Area

NASA Astrophysics Data System (ADS)

Moon, H.; Kim, C.; Lee, W.

2016-06-01

Regarding spatial location positioning, indoor location positioning theories based on wireless communication techniques such as Wi-Fi, beacon, UWB and Bluetooth has widely been developing across the world. These techniques are mainly focusing on spatial location detection of customers using fixed wireless APs and unique Tags in the indoor environment. Besides, since existing detection equipment and techniques using ultrasound or sound etc. to detect buried persons and identify survival status for them cause 2nd damages on the collapsed debris for rescuers. In addition, it might take time to check the buried persons. However, the collapsed disaster sites should consider both outdoor and indoor environments because empty spaces under collapsed debris exists. In order to detect buried persons from the empty spaces, we should collect wireless signals with Wi-Fi from their mobile phone. Basically, the Wi-Fi signal measure 2-D location. However, since the buried persons have Z value with burial depth, we also should collect barometer sensor data from their mobile phones in order to measure Z values according to weather conditions. Specially, for quick accessibility to the disaster area, a drone (UAV; Unmanned Arial Vehicle) system, which is equipped with a wireless detection module, was introduced. Using these framework, this study aims to provide the rescuers with effective rescue information by calculating 3-D location for buried persons based on the wireless and barometer sensor fusion.

Dynamics and Collapse in a Power System Model with Voltage Variation: The Damping Effect.

PubMed

Ma, Jinpeng; Sun, Yong; Yuan, Xiaoming; Kurths, Jürgen; Zhan, Meng

2016-01-01

Complex nonlinear phenomena are investigated in a basic power system model of the single-machine-infinite-bus (SMIB) with a synchronous generator modeled by a classical third-order differential equation including both angle dynamics and voltage dynamics, the so-called flux decay equation. In contrast, for the second-order differential equation considering the angle dynamics only, it is the classical swing equation. Similarities and differences of the dynamics generated between the third-order model and the second-order one are studied. We mainly find that, for positive damping, these two models show quite similar behavior, namely, stable fixed point, stable limit cycle, and their coexistence for different parameters. However, for negative damping, the second-order system can only collapse, whereas for the third-order model, more complicated behavior may happen, such as stable fixed point, limit cycle, quasi-periodicity, and chaos. Interesting partial collapse phenomena for angle instability only and not for voltage instability are also found here, including collapse from quasi-periodicity and from chaos etc. These findings not only provide a basic physical picture for power system dynamics in the third-order model incorporating voltage dynamics, but also enable us a deeper understanding of the complex dynamical behavior and even leading to a design of oscillation damping in electric power systems.

Metastability versus collapse following a quench in attractive Bose-Einstein condensates

NASA Astrophysics Data System (ADS)

Golde, Jake; Ruhl, Joanna; Olshanii, Maxim; Dunjko, Vanja; Datta, Sumita; Malomed, Boris A.

2018-05-01

We consider a Bose-Einstein condensate (BEC) with attractive two-body interactions in a cigar-shaped trap, initially prepared in its ground state for a given negative scattering length, which is quenched to a larger absolute value of the scattering length. Using the mean-field approximation, we compute numerically, for an experimentally relevant range of aspect ratios and initial strengths of the coupling, two critical values of quench. One corresponds to the weakest attraction strength, the quench to which causes the system to collapse before completing even a single return from the narrow configuration (pericenter) in its breathing cycle. The other is a similar critical point for the occurrence of collapse before completing two returns. In the latter case, we also compute the limiting value, as we keep increasing the strength of the postquench attraction towards its critical value, of the time interval between the first two pericenters. We also use a Gaussian variational model to estimate the critical quenched attraction strength below which the system is stable against the collapse for long times. These time intervals and critical attraction strengths, apart from being fundamental properties of nonlinear dynamics of self-attractive BECs, may provide clues to the design of upcoming experiments that are trying to create robust BEC breathers.

Fragmentation inside atomic cooling haloes exposed to Lyman-Werner radiation

NASA Astrophysics Data System (ADS)

Regan, John A.; Downes, Turlough P.

2018-04-01

Supermassive stars born in pristine environments in the early Universe hold the promise of being the seeds for the supermassive black holes observed as high redshift quasars shortly after the epoch of reionisation. H2 suppression is thought to be crucial in order to negate normal Population III star formation and allow high accretion rates to drive the formation of supermassive stars. Only in the cases where vigorous fragmentation is avoided will a monolithic collapse be successful, giving rise to a single massive central object. We investigate the number of fragmentation sites formed in collapsing atomic cooling haloes subject to various levels of background Lyman-Werner flux. The background Lyman-Werner flux manipulates the chemical properties of the gas in the collapsing halo by destroying H2. We find that only when the collapsing gas cloud shifts from the molecular to the atomic cooling regime is the degree of fragmentation suppressed. In our particular case, we find that this occurs above a critical Lyman-Werner background of J ˜ 10 J21. The important criterion being the transition to the atomic cooling regime rather than the actual value of J, which will vary locally. Once the temperature of the gas exceeds T ≳ 104 K and the gas transitions to atomic line cooling, then vigorous fragmentation is strongly suppressed.

Urban/rural interface: Governing the chaos

NASA Astrophysics Data System (ADS)

Ferreira, António

2016-04-01

Cities have become recently the home for more than half of the world's population. Cities are often seen as ecological systems just a short step away from collapse [Newman 2006]. Being a human construction, cities disrupt the natural cycles and the patterns of temporal and spatial distribution of environmental and ecological processes. Urbanization produces ruptures in biota, water, energy and nutrients connectivity that can lead to an enhanced exposure to disruptive events that hamper the wellbeing and the resilience of urban communities in a global change context. An important issue in what concerns urban sprawl is the interface between the urban and the rural territories. Being an extremely dynamic landscape, and assuring some quality of life and buffering some of the pervasive negative impacts of urban areas in terms of disrupting the function of the natural ecosystems, in limit situations this interface can act as a conveyor belt of catastrophic events originated in the rural world, into the urban space. The Coimbra 2005 wildfire is a fine example of how a poorly managed urban/rural interface can put populations in danger, by allowing the fire to spread towards the urban green infrastructure, burning houses in the process. Major river flows that flood urban areas are also good examples of the lack of management and planning can result in the loss of assets and even put in danger human lives. This presentation reviews the impact of extreme events and the transmission from the urban to the rural worlds, but also from the rural to the urban territories, and establishes the need to govern risk at various levels and using the full range of governance tools.

Comments on "International Development Perspectives for the 90s".

PubMed

Klein, L R

1991-01-01

Comments on the UN paper on the Development Decade of the 1980s and the next decade of the 1990s by Gamani Corea are presented. Corea's statements about the future are considered fair, but negative and lacking in quantitative input. As an econometrician and a quantitative economist, the author feels that the shortterm and mediumterm economic prospects are that 1988 was a good year, 1989 all right, and 1990 was recessionary for some countries. Recovery is anticipated by 1992. The Gulf crisis of 1990-91 caused fluctuations in energy prices and uncertainty or fear in people, which is hoped to be transitory and without major impact on economic matters. Positive expansion in the world economy after 1992 is anticipated, in spite of the recessions in the UK and some Nordic countries. Western Europe slowed, but the advent of the Single Market is favorable to an upswing. The Asia/Pacific arena is strong, and achievements in South Korea are considerable. Mexico, Venezuela, Colombia, and Chile are promising. Other economic problems in Latin America are only temporary. South Asia has done well. The Middle East and North Africa may have more lasting consequences of the Gulf war. Sub-Saharan Africa is in trouble with the race between population growth and food supplies, and negative or near zero growth rates/capita. Developing countries are experiencing severe recessionary adjustment periods in world economic malaise. With the collapse of socialism, there is no viable "Second World," and there are industrialized and developing countries. Eastern Europe and the USSR have a skilled population with the potential for producing world class goods and services. Primary commodity markets are expected to rise again which will strengthen export earnings in the developing world. Macroeconomic visions of hope are based on contingencies: financial fragility, issues related to the Gulf crisis, poor financial conditions in the US and to a certain extent in Japan and other financial centers. Trade negotiations in the Uruguay Round are in difficulty, which restricts free trade, and dilutes strong and vigorous activity which helps development. The economic restructuring of Europe is moving more slowly, but the Arms race is still extant in Third World countries such as Iraq. Price stabilization efforts may be futile attempts when underlying behavior patterns of production and consumption take over. Europe is the primary growth area. The Peace Dividend has been reduced because of Iraq's postures. South/South trade may be an option for developing countries. There is potential for expansion in e.g., and electronics, medical care, telecommunications, bioengineering, metallurgy, software construction. Technology and economics and international cooperation and coordination are hopeful prospects for the future.

Supernova signatures of neutrino mass ordering

NASA Astrophysics Data System (ADS)

Scholberg, Kate

2018-01-01

A suite of detectors around the world is poised to measure the flavor-energy-time evolution of the ten-second burst of neutrinos from a core-collapse supernova occurring in the Milky Way or nearby. Next-generation detectors to be built in the next decade will have enhanced flavor sensitivity and statistics. Not only will the observation of this burst allow us to peer inside the dense matter of the extreme event and learn about the collapse processes and the birth of the remnant, but the neutrinos will bring information about neutrino properties themselves. This review surveys some of the physical signatures that the currently-unknown neutrino mass pattern will imprint on the observed neutrino events at Earth, emphasizing the most robust and least model-dependent signatures of mass ordering.

ENVIRONMENTAL CFD SIMULATION AND VISUALIZATION: EXAMPLES IN SUPPORT OF THE RECONSTRUCTION OF THE SMOKE/DUST PLUME FROM THE WORLD TRADE CENTER SITE FOLLOWING THE EVENTS OF SEPTEMBER 11, 2001

EPA Science Inventory

The Poster will present the process of Computational Fluid Dynamics (CFD) simulations through examples supporting the reconstruction of the smoke/dust plumes following the collapse of the WTC towers on September 11, 2001.

Understanding the pathway of toxic air polluta...

The Origins of the Transformation of the Defense Language Program

ERIC Educational Resources Information Center

Raugh, Harold E., Jr.

2006-01-01

The horrific events of 11 September 2001, when four hijacked jetliners crashed into and collapsed the twin-towered World Trade Center in New York, slammed into the Pentagon, and nose-dived into a field in rural Pennsylvania (ostensibly on a mission to destroy the U.S. Capitol or the White House), have been indelibly etched into the nation's…

Ethics Education in the Australian Accounting Curriculum: A Longitudinal Study Examining Barriers and Enablers

ERIC Educational Resources Information Center

Dellaportas, Steven; Kanapathippillai, Sutharson; Khan, Arifur; Leung, Philomena

2014-01-01

The increasing significance of ethics in the accounting profession is evidenced by the seminal events that witnessed the collapse of major corporations (e.g. Enron and WorldCom); regulatory interventions (e.g. Sarbanes-Oxley Act in the USA and the CLERP 9 Act in Australia); and calls for increased ethics interventions in the accounting curriculum.…

CHARACTERIZATION OF THE DUST/SMOKE AEROSOL THAT SETTLED EAST OF THE WORLD TRADE CENTER (WTC) IN LOWER MANHATTAN AFTER THE COLLAPSE OF THE WTC SEPTEMBER 11, 2001. (R827351)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

A computerized, self-administered questionnaire to evaluate posttraumatic stress among firefighters after the World Trade Center collapse.

PubMed

Corrigan, Malachy; McWilliams, Rita; Kelly, Kerry J; Niles, Justin; Cammarata, Claire; Jones, Kristina; Wartenberg, Daniel; Hallman, William K; Kipen, Howard M; Glass, Lara; Schorr, John K; Feirstein, Ira; Prezant, David J

2009-11-01

We sought to determine the frequency of psychological symptoms and elevated posttraumatic stress disorder (PTSD) risk among New York City firefighters after the World Trade Center (WTC) attack and whether these measures were associated with Counseling Services Unit (CSU) use or mental health-related medical leave over the first 2.5 years after the attack. Shortly after the WTC attack, a computerized, binary-response screening questionnaire was administered. Exposure assessment included WTC arrival time and "loss of a co-worker while working at the collapse." We determined elevated PTSD risk using thresholds derived from Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, and a sensitivity-specificity analysis. Of 8487 participants, 76% reported at least 1 symptom, 1016 (12%) met criteria for elevated PTSD risk, and 2389 (28%) self-referred to the CSU, a 5-fold increase from before the attack. Higher scores were associated with CSU use, functional job impairment, and mental health-related medical leave. Exposure-response gradients were significant for all outcomes. This screening tool effectively identified elevated PTSD risk, higher CSU use, and functional impairment among firefighters and therefore may be useful in allocating scarce postdisaster mental health resources.

Investigation of Seismic Waves from Non-Natural Sources: A Case Study for Building Collapse and Surface Explosion

NASA Astrophysics Data System (ADS)

Houng, S.; Hong, T.

2013-12-01

The nature and excitation mechanism of incidents or non-natural events have been widely investigated using seismological techniques. With introduction of dense seismic networks, small-sized non-natural events such as building collapse and chemical explosions are well recorded. Two representative non-natural seismic sources are investigated. A 5-story building in South Korea, Sampoong department store, was collapsed in June 25, 1995, causing casualty of 1445. This accident is known to be the second deadliest non-terror-related building collapse in the world. The event was well recorded by a local station in ~ 9 km away. P and S waves were recorded weak, while monotonic Rayleigh waves were observed well. The origin time is determined using surface-wave arrival time. The magnitude of event is determined to be 1.2, which coincides with a theoretical estimate based on the mass and volume of building. Synthetic waveforms are modeled for various combinations of velocity structures and source time functions, which allow us to constrain the process of building collapse. It appears that the building was collapsed once within a couple of seconds. We also investigate a M2.1 chemical explosion at a fertilizer plant in Texas on April 18, 2013. It was reported that more than one hundred people were dead or injured by the explosion. Seismic waveforms for nearby stations are collected from Incorporated Research Institution of Seismology (IRIS). The event was well recorded at stations in ~500 km away from the source. Strong acoustic signals were observed at stations in a certain great-circle direction. This observation suggests preferential propagation of acoustic waves depending on atmospheric environment. Waveform cross-correlation, spectral analysis and waveform modeling are applied to understand the source physics. We discuss the nature of source and source excitation mechanism.

A study of earthquake-induced building detection by object oriented classification approach

NASA Astrophysics Data System (ADS)

Sabuncu, Asli; Damla Uca Avci, Zehra; Sunar, Filiz

2017-04-01

Among the natural hazards, earthquakes are the most destructive disasters and cause huge loss of lives, heavily infrastructure damages and great financial losses every year all around the world. According to the statistics about the earthquakes, more than a million earthquakes occur which is equal to two earthquakes per minute in the world. Natural disasters have brought more than 780.000 deaths approximately % 60 of all mortality is due to the earthquakes after 2001. A great earthquake took place at 38.75 N 43.36 E in the eastern part of Turkey in Van Province on On October 23th, 2011. 604 people died and about 4000 buildings seriously damaged and collapsed after this earthquake. In recent years, the use of object oriented classification approach based on different object features, such as spectral, textural, shape and spatial information, has gained importance and became widespread for the classification of high-resolution satellite images and orthophotos. The motivation of this study is to detect the collapsed buildings and debris areas after the earthquake by using very high-resolution satellite images and orthophotos with the object oriented classification and also see how well remote sensing technology was carried out in determining the collapsed buildings. In this study, two different land surfaces were selected as homogenous and heterogeneous case study areas. In the first step of application, multi-resolution segmentation was applied and optimum parameters were selected to obtain the objects in each area after testing different color/shape and compactness/smoothness values. In the next step, two different classification approaches, namely "supervised" and "unsupervised" approaches were applied and their classification performances were compared. Object-based Image Analysis (OBIA) was performed using e-Cognition software.

Going South: Analysis of an Historic Project Engineering Failure

NASA Technical Reports Server (NTRS)

Scott, John H.

2009-01-01

NASA's successful conduct of the Apollo Program greatly enhanced the prestige of the United States and remains broadly accepted as America's gift to all Mankind. NASA's accomplishments continue to amaze the world. With the Vision for Space Exploration (VSE) Americans once again tasked NASA to carry out a project that is expected to provide inspiration and economic stimulus to the United States and to the world. In preparation NASA has thoroughly examined space program precedents. There is, however, another precedent which has not been examined in this context but whose scope and environment in many ways parallel the VSE. This project was initiated by a team that had, ten years before, successfully completed an effort that, at a cost of $173 billion (in 2008 dollars), had pushed the envelope of technology, brought economic growth, established their country as the world leader in engineering, and been broadly accepted as that country's gift to all Mankind. The new project was again inspired by popular desire to enhance national prestige and make yet another major contribution to Humanity. This effort was predicted to require eight years and $156 billion (2008 dollars). However, after nine years and expenditures of 96% beyond the baseline, the project collapsed amid bankruptcy, political scandal, and criminal prosecution. This paper applies current project management metrics, such as earned value analysis, to review the strategic decisions in this historic failure and describe its ultimate collapse. Key mistakes are identified, and lessons are drawn which may prove useful in guiding the VSE.

Going South: Lessons from an Historic Project Failure

NASA Technical Reports Server (NTRS)

Scott, John H.

2009-01-01

NASA's successful conduct of the Apollo Program greatly enhanced the prestige of the United States and remains broadly accepted as America's gift to all Mankind. NASA's accomplishments continue to amaze the world. With the Vision for Space Exploration (VSE) Americans once again tasked NASA to carry out a project that is expected to provide inspiration and economic stimulus to the United States and to the world. In preparation NASA has thoroughly examined space program precedents. There is, however, another precedent which has not been examined in this context but whose scope and environment in many ways parallel the VSE. This project was initiated by a team that had, ten years before, successfully completed an effort that, at a cost of $151 billion (2008 values), had pushed the envelope of technology, brought economic growth, established their country as the world leader in engineering, and been broadly accepted as their country s gift to Mankind. The new project was again inspired by popular desire to enhance national prestige and make yet another major contribution to Humanity. The new effort was predicted to require eight years and $156 billion (2008 values). However, after eight years and expenditures of 80% beyond the baseline, the project collapsed amid bankruptcy, political scandal, and criminal prosecution. This paper applies current aerospace project metrics, such as earned value analysis, to review the strategic decisions in this historic failure and describe its ultimate collapse. Key mistakes are identified, and lessons are drawn which may prove useful in guiding the VSE.

What would have happened to the ozone layer if chlorofluorocarbons (CFCs) had not been regulated?

NASA Astrophysics Data System (ADS)

Newman, P. A.; Oman, L. D.; Douglass, A. R.; Fleming, E. L.; Frith, S. M.; Hurwitz, M. M.; Kawa, S. R.; Jackman, C. H.; Krotkov, N. A.; Nash, E. R.; Nielsen, J. E.; Pawson, S.; Stolarski, R. S.; Velders, G. J.

2008-12-01

Ozone depletion by chlorofluorocarbons (CFCs) was first proposed by Molina and Rowland in their 1974 Nature paper. Since that time, the scientific connection between ozone losses and CFCs and other ozone depleting substances (ODSs) has been firmly established with laboratory measurements, atmospheric observations, and modeling research. The nations of the world implemented the Montreal Protocol (and amendments) which stopped ODS production in 1992. In this presentation we use a fully coupled radiation- chemical-dynamical model to simulate a future world where ODSs were never regulated and ODS production grew at an annual rate of 3%. In this "world avoided" simulation, 17% of the globally average column ozone is destroyed by 2020, and 67% is destroyed by 2065 in comparison to 1980. Large ozone depletions in the polar region become year-round rather than just seasonal as is currently observed in the Antarctic ozone hole. Very large temperature decreases are observed in response to circulation changes and decreased shortwave radiation absorption by ozone. Ozone levels in the tropical lower stratosphere remain constant until about 2053 and then collapse to near zero by 2058 as a result of heterogeneous chemical processes (as currently observed in the Antarctic ozone hole). The tropical cooling that triggers the ozone collapse is caused by an increase of the tropical upwelling. In response to ozone changes, ultraviolet (UV) radiation increases, tripling the erythemal (sunburn) radiation in the northern summer mid-latitudes by 2065.

Numerical relativity beyond astrophysics.

PubMed

Garfinkle, David

2017-01-01

Though the main applications of computer simulations in relativity are to astrophysical systems such as black holes and neutron stars, nonetheless there are important applications of numerical methods to the investigation of general relativity as a fundamental theory of the nature of space and time. This paper gives an overview of some of these applications. In particular we cover (i) investigations of the properties of spacetime singularities such as those that occur in the interior of black holes and in big bang cosmology. (ii) investigations of critical behavior at the threshold of black hole formation in gravitational collapse. (iii) investigations inspired by string theory, in particular analogs of black holes in more than 4 spacetime dimensions and gravitational collapse in spacetimes with a negative cosmological constant.

Evolution of geodesic congruences in a gravitationally collapsing scalar field background

NASA Astrophysics Data System (ADS)

Shaikh, Rajibul; Kar, Sayan; DasGupta, Anirvan

2014-12-01

The evolution of timelike geodesic congruences in a spherically symmetric, nonstatic, inhomogeneous spacetime representing gravitational collapse of a massless scalar field is studied. We delineate how initial values of the expansion, rotation, and shear of a congruence, as well as the spacetime curvature, influence the global behavior and focusing properties of a family of trajectories. Under specific conditions, the expansion scalar is shown to exhibit a finite jump (from negative to positive value) before focusing eventually occurs. This nonmonotonic behavior of the expansion, observed in our numerical work, is successfully explained through an analysis of the equation for the expansion. Finally, we bring out the role of the metric parameters (related to nonstaticity and spatial inhomogeneity) in shaping the overall behavior of geodesic congruences.

Current collapse in tunneling transport through benzene.

PubMed

Hettler, M H; Wenzel, W; Wegewijs, M R; Schoeller, H

2003-02-21

We investigate the electrical transport through a system of benzene coupled to metal electrodes by electron tunneling. Using electronic structure calculations, a semiquantitative model for the pi electrons of the benzene is derived that includes general two-body interactions. After exact diagonalization of the benzene model the transport is computed using perturbation theory for weak electrode-benzene coupling (golden rule approximation). We include the effect of an applied electric field on the molecular states, as well as radiative relaxation. We predict a current collapse and strong negative differential conductance due to a "blocking" state when the electrode is coupled to the para-position of benzene. In contrast, for coupling to the meta-position, a series of steps in the I-V curve is found.

Numerical relativity beyond astrophysics

NASA Astrophysics Data System (ADS)

Garfinkle, David

2017-01-01

Though the main applications of computer simulations in relativity are to astrophysical systems such as black holes and neutron stars, nonetheless there are important applications of numerical methods to the investigation of general relativity as a fundamental theory of the nature of space and time. This paper gives an overview of some of these applications. In particular we cover (i) investigations of the properties of spacetime singularities such as those that occur in the interior of black holes and in big bang cosmology. (ii) investigations of critical behavior at the threshold of black hole formation in gravitational collapse. (iii) investigations inspired by string theory, in particular analogs of black holes in more than 4 spacetime dimensions and gravitational collapse in spacetimes with a negative cosmological constant.

Control of the filamentation distance and pattern in long-range atmospheric propagation

NASA Astrophysics Data System (ADS)

Eisenmann, Shmuel; Louzon, Einat; Katzir, Yiftach; Palchan, Tala; Zigler, Arie; Sivan, Yonatan; Fibich, Gadi

2007-03-01

We use the double-lens setup [10, 11] to achieve a 20-fold delay of the filamentation distance of non-chirped 120 fs pulses propagating in air, from 16m to 330m. At 330m, the collapsing pulse is sufficiently powerful to create plasma filaments. We also show that the scatter of the filaments at 330m can be significantly reduced by tilting the second lens. To the best of our knowledge, this is the longest distance reported in the Literature at which plasma filaments were created and controlled. Finally, we show that the peak power at the onset of collapse is significantly higher with the double-lens setup, compared with the standard negative chirping approach.

[Coral reefs in the face of ecological threats of XXI century].

PubMed

Tkachenko, K S

2015-01-01

To date, more than a quarter of tropical coral reefs of the World Ocean are believed to be totally de- stroyed. Given the present rates of reefs degradation, this value may be doubled in the nearest 30 years. For the essential part of coastal community, the destruction of coral ecosystems implies the loss of the major food sources, natural protection from storms, and significant (if not the only) revenue from exploi- tation of reefs especially in tourism industry. Finally, the disappearance of low-laying coral islands may threat the local communities by deprivation of living space. Global negative effects include temperature anomalies of sea surface waters and an increase of atmospheric CO2 concentration leading to ocean acidification. Local negative effects are related to in- crease of sedimentation and eutrophication, cyclone and storm passes, coral diseases, chemical pollution, mechanical destruction of corals by humans, anthropogenic depletion of functional groups of fish and invertebrates. An entire set of responses of coral ecosystems to stressful factors on the levels of both separate taxa and ecosystem is discussed. An analysis of published data suggests that with high probability the tropical coral communities will come to collapse stage by the middle of the current century at more than 50% of the area of their biogeographic range, especially in the regions of dense human population. At the most optimistic scenario, complex effect of reviewed negative factors will result in coral ecosystems main- taining in some areas. However, after global transformations, these ecosystems will be dominated by the most resistant taxa, mainly massive and encrusting forms of long-lived species with low growth rates and high competitive ability. Among such taxa, Poritidae demonstrates the highest adaptive capability. At the most pessimistic scenario, scleractinian communities will be replaced by alternative communities of macroalgae and non-calcareous anthozoans.

Certificate of Online Learning and Teaching (COLT) at the University of Hawaii: A Horse of Another Color for Earning College Credits

ERIC Educational Resources Information Center

Menchaca, Michael P.; Hoffman, Ellen S.

2013-01-01

Current conventional wisdom may perceive that higher education is outdated and maybe even likely to collapse. Online education is often predicted to replace brick-and-mortar campuses with systems providing students access to world-class learning via smartphones and tablets. Many private and commercial ventures are embracing such concepts. However,…

Literacies of (Post)Socialist Childhood: Alternative Readings of Socialist Upbringings and Neoliberal Futures

ERIC Educational Resources Information Center

Mead, Michael A.; Silova, Iveta

2013-01-01

In the former Soviet Union, the upbringing of children in the spirit of Marxist-Leninist values was central to the project of societal transformation. More than 20 years after the collapse of the Soviet Union, it is important to understand how the education of young children in this region has changed in response to a world rapidly globalising and…

KSC-2014-3809

NASA Image and Video Library

2014-09-11

Cape Canaveral, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel gathered near the 9/11 memorial after a ceremony commemorating the 13th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Photo credit: Jim Grossmann

University Learning in Times of Crisis: The Role of IT

ERIC Educational Resources Information Center

Todorova, Nelly; Bjorn-Andersen, Niels

2011-01-01

When the physical world of the University of Canterbury in Christchurch collapsed in a 6.3 magnitude earthquake at 12.51 pm on 22 February 2011, IT in general and the online learning platform, in particular, gave a second life from day one. It worked, but it was not an easy task. The university was able to salvage the semester and keep the…

Tsunamis generated by eruptions from mount st. Augustine volcano, alaska.

PubMed

Kienle, J; Kowalik, Z; Murty, T S

1987-06-12

During an eruption of the Alaskan volcano Mount St. Augustine in the spring of 1986, there was concern about the possibility that a tsunami might be generated by the collapse of a portion of the volcano into the shallow water of Cook Inlet. A similar edifice collapse of the volcano and ensuing sea wave occurred during an eruption in 1883. Other sea waves resulting in great loss of life and property have been generated by the eruption of coastal volcanos around the world. Although Mount St. Augustine remained intact during this eruptive cycle, a possible recurrence of the 1883 events spurred a numerical simulation of the 1883 sea wave. This simulation, which yielded a forecast of potential wave heights and travel times, was based on a method that could be applied generally to other coastal volcanos.

Ukrainian Youth Development: Music and Creativity, a Route to Youth Betterment

ERIC Educational Resources Information Center

Eckstrom, Erika

2007-01-01

In north-eastern Ukraine, the collapse of the Soviet Union has caused a heavy economic depression. This has forced workers to migrate abroad, leaving young children and teenagers back home. Without adult supervision and influence, these young people are left without direction. Open to negative influences such as alcohol and drugs, they are at a…

Quantum chemical study on the stability of honeybee queen pheromone against atmospheric factors.

PubMed

Shi, Rongwei; Liu, Fanglin

2016-06-01

The managed honeybee, Apis mellifera, has been experienced a puzzling event, termed as colony collapse disorder (CCD), in which worker bees abruptly disappear from their hives. Potential factors include parasites, pesticides, malnutrition, and environmental stresses. However, so far, no definitive relationship has been established between specific causal factors and CCD events. Here we theoretically test whether atmospheric environment could disturb the chemical communication between the queen and their workers in a colony. A quantum chemistry method has been used to investigate for the stability of the component of A. mellifera queen mandibular pheromone (QMP), (E)-9-keto-2-decenoic acid (9-ODA), against atmospheric water and free radicals. The results show that 9-ODA is less likely to react with water due to the high barrier heights (~36.5 kcal · mol(-1)) and very low reaction rates. However, it can easily react with triplet oxygen and hydroxyl radicals because of low or negative energy barriers. Thus, the atmospheric free radicals may disturb the chemical communication between the queen and their daughters in a colony. Our pilot study provides new insight for the cause of CCD, which has been reported throughout the world.

Income and poverty in a developing economy

NASA Astrophysics Data System (ADS)

Chattopadhyay, A. K.; Ackland, G. J.; Mallick, S. K.

2010-09-01

We present a stochastic agent-based model for the distribution of personal incomes in a developing economy. We start with the assumption that incomes are determined both by individual labour and by stochastic effects of trading and investment. The income from personal effort alone is distributed about a mean, while the income from trade, which may be positive or negative, is proportional to the trader's income. These assumptions lead to a Langevin model with multiplicative noise, from which we derive a Fokker-Planck (FP) equation for the income probability density function (IPDF) and its variation in time. We find that high earners have a power law income distribution while the low-income groups have a Levy IPDF. Comparing our analysis with the Indian survey data (obtained from the world bank website: http://go.worldbank.org/SWGZB45DN0) taken over many years we obtain a near-perfect data collapse onto our model's equilibrium IPDF. Using survey data to relate the IPDF to actual food consumption we define a poverty index (Sen A. K., Econometrica., 44 (1976) 219; Kakwani N. C., Econometrica, 48 (1980) 437), which is consistent with traditional indices, but independent of an arbitrarily chosen "poverty line" and therefore less susceptible to manipulation.

The wealth, health and wellbeing of Ireland's older people before and during the economic crisis.

PubMed

Barrett, A; O'Sullivan, V

2014-07-03

The economic crisis of 2008/9 was felt more acutely in Ireland relative to elsewhere and culminated in the international bailout in 2010. Given the economic collapse, Ireland provides an ideal case-study of the link between wealth collapses and movements in variables such as health and well-being. Using nationally-representative samples of older people collected before and during the crisis, we show that mean net assets fell by 45 percent between 2006/7 and 2012/13. In spite of this massive fall in wealth, measures of health and well-being remained broadly unchanged. However, expectations about future living standards became less optimistic. The results tend to support the findings of other recent studies that recessions do not have widespread negative effects on health and well-being.

Linear feedback stabilization of a dispersively monitored qubit

NASA Astrophysics Data System (ADS)

Patti, Taylor Lee; Chantasri, Areeya; García-Pintos, Luis Pedro; Jordan, Andrew N.; Dressel, Justin

2017-08-01

The state of a continuously monitored qubit evolves stochastically, exhibiting competition between coherent Hamiltonian dynamics and diffusive partial collapse dynamics that follow the measurement record. We couple these distinct types of dynamics together by linearly feeding the collected record for dispersive energy measurements directly back into a coherent Rabi drive amplitude. Such feedback turns the competition cooperative and effectively stabilizes the qubit state near a target state. We derive the conditions for obtaining such dispersive state stabilization and verify the stabilization conditions numerically. We include common experimental nonidealities, such as energy decay, environmental dephasing, detector efficiency, and feedback delay, and show that the feedback delay has the most significant negative effect on the feedback protocol. Setting the measurement collapse time scale to be long compared to the feedback delay yields the best stabilization.

Interaction of Intense Short Laser Pulses with Air and Dielectric Materials

NASA Astrophysics Data System (ADS)

Eisenmann, S.; Katzir, Y.; Zigler, A.; Fibich, G.; Louzon, E.; Ehrlich, Y.; Henis, Z.; Pecker, S.; Fisher, D.; Fraenkel, M.

A study of the propagation of intense short laser pulses in air and the interaction of these pulses with distant targets is described. It is shown that the beam filamentation pattern can be controlled by introducing beam astigmatism. In addition, it is demonstrated that the collapse distance of intense femtosecond laser beams scales as P-1/2 for input powers that are moderately above the critical power for self focusing, and that at higher powers the collapse distance scales as P-1. Related to the interaction of intense short pulses with distant targets, it is measured that the threshold fluence for optical damage in wide gap materials is lower by up to 20% for negatively chirped pulses than for positively chirped, at pulse durations ranging from 60 fs to 1 ps.

Introduction. Progress in astronomy: from gravitational waves to space weather.

PubMed

Thompson, J Michael T

2008-12-13

This brief paper introduces and reviews the 'visions of the future' articles prepared by leading young scientists throughout the world for the first of two Christmas 2008 Triennial issues of Phil. Trans. R. Soc. A, devoted, respectively, to astronomy and Earth science. Contributions in astronomy include the very topical gamma-ray bursts, new ideas on stellar collapse and the unusual atmospheres of synchronized planets orbiting nearby stars.

The Power of Film to Educate and Miseducate Pre-Service Teachers: A Phenomenological Analysis of "Hidalgo" and Cultural Representation of Muslims Post 9/11

ERIC Educational Resources Information Center

Fontaine, Haroldo A.

2010-01-01

In this article, the author considers three of today's pre-service teachers who have each watched the World Trade Center towers collapse on broadcast television, viewed the film "Hidalgo," and participated in subsequent interviews regarding the movie. Specifically, the author wants to examine the extent to which the pre-service teachers in this…

The Italian Expedition in the Russian Campaign 1941-43: A Pronounced Failure

DTIC Science & Technology

This monograph investigates the Italian Expedition in the Russian campaign during the Second World War from an operational perspective. It seeks to...identify those factors relevant for practicing operational art that caused the collapse of the Italian forces in 1943. Specifically, the monograph ...commands. The conclusion of the monograph depicts several lessons for current and future operational planners. The latter have to be ready to properly frame

The Haunted Inkbottle: Problems of Artistic Communication in Modernism

DTIC Science & Technology

1989-07-07

Whether an artist relates his consciousness to his world--and ultimately to his audience--through physical , intellectual, or spiritual means is the crucial...to his audience--through physical , intellectual, or spiritual means is the crucial factor determining the success or failure of the artist in reaching...the point of physical collapse. Donald Spoto, however, in his biography of the playwright, remarks that company "employment records show that he did

A Computerized, Self-Administered Questionnaire to Evaluate Posttraumatic Stress Among Firefighters After the World Trade Center Collapse

PubMed Central

Corrigan, Malachy; McWilliams, Rita; Kelly, Kerry J.; Niles, Justin; Cammarata, Claire; Jones, Kristina; Wartenberg, Daniel; Hallman, William K.; Kipen, Howard M.; Glass, Lara; Schorr, John K.; Feirstein, Ira

2009-01-01

Objectives. We sought to determine the frequency of psychological symptoms and elevated posttraumatic stress disorder (PTSD) risk among New York City firefighters after the World Trade Center (WTC) attack and whether these measures were associated with Counseling Services Unit (CSU) use or mental health–related medical leave over the first 2.5 years after the attack. Methods. Shortly after the WTC attack, a computerized, binary-response screening questionnaire was administered. Exposure assessment included WTC arrival time and “loss of a co-worker while working at the collapse.” We determined elevated PTSD risk using thresholds derived from Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, and a sensitivity-specificity analysis. Results. Of 8487 participants, 76% reported at least 1 symptom, 1016 (12%) met criteria for elevated PTSD risk, and 2389 (28%) self-referred to the CSU, a 5-fold increase from before the attack. Higher scores were associated with CSU use, functional job impairment, and mental health–related medical leave. Exposure–response gradients were significant for all outcomes. Conclusions. This screening tool effectively identified elevated PTSD risk, higher CSU use, and functional impairment among firefighters and therefore may be useful in allocating scarce postdisaster mental health resources. PMID:19890176

Summary of the development of a signature for detection of residual dust from collapse of the World Trade Center buildings

PubMed Central

Lowers, Heather A; Meeker, Gregory P; Lioy, Paul J; Lippmann, Morton

2014-01-01

The collapse of the World Trade Center (WTC) towers on September 11, 2001, caused lower Manhattan and adjacent areas to be covered in millimeters to centimeters of dust. WTC dust penetrated into indoor spaces, and public health concerns remain regarding exposure to possible residual dust in the affected areas. The goal of the studies outlined in this review was to determine which, if any, components of the bulk WTC dust are sufficiently above typical background dust levels in New York City to develop an analytical method to screen for the component(s). Components of the <150-µm-size fraction of the dust are gypsum, phases compatible with crushed concrete, man-made vitreous fibers (MMVFs), silica, lead, chrysotile asbestos, and other materials. Slag wool was the most common WTC MMVF, whereas soda-lime glass and rock wool were minor to trace constituents. Most background samples also contained gypsum, phases compatible with concrete, and MMVF. However, the proportions of the various MMVF in background samples are typically unlike those characteristic of bulk WTC dust. Results indicate that slag wool can be used as a signature marker to identify areas that contain potential residual WTC dust contamination at concentrations that are less than average background levels for the material. PMID:18478046

Prevalence of tidal expiratory flow limitation in preschool children with and without respiratory symptoms: application of the negative expiratory pressure (NEP) method.

PubMed

JIRICKOVA, A; SULC, J; POHUNEK, P; KITTNAR, O; DOHNALOVA, A; KOFRANEK, J

2009-01-01

Negative expiratory pressure (NEP) applied at the mouth during tidal expiration provides a non-invasive method for detecting expiratory flow limitation. Forty-two children were studied, i.e. 25 children with different respiratory symptoms (R) and 17 without any respiratory symptoms (NR). Children were examined without any sedation. A preset NEP of -5 cm H(2)O was applied; its duration did not exceed duration of tidal expiration. A significance of FL was judged by determining of a flow-limited range (in % of tidal volume). FL was found in 48 % children of R group. No patient of the NR group elicited FL (P<0.001 R vs. NR). The frequency of upper airway collapses was higher in R group (12 children) than in NR group (5 children). In conclusion, a high frequency of tidal FL in the R group was found, while it was not present in NR group. A relatively high frequency of expiratory upper airway collapses was found in both groups, but it did not differ significantly. NEP method represents a reasonable approach for tidal flow limitation testing in non-sedated preschool children.

Spectroscopic and x-ray diffraction analyses of asbestos in the World Trade Center dust:

USGS Publications Warehouse

Swayze, Gregg A.; Clark, Roger N.; Sutley, Stephen J.; Hoefen, Todd M.; Plumlee, Geoffrey S.; Meeker, Gregory P.; Brownfield, Isabelle; Livo, Keith E.; Morath, Laurie C.

2009-01-01

On September 17 and 18, 2001, samples of settled dust and airfall debris were collected from 34 sites within a 1-km radius of the WTC collapse site, including a sample from an indoor location unaffected by rainfall, and samples of insulation from two steel beams at Ground Zero. Laboratory spectral and x-ray diffraction analyses of the field samples detected trace levels of serpentine minerals, including chrysotile asbestos, in about two-thirds of the dust samples at concentrations at or below ~1 wt%. One sample of a beam coating material contained up to 20 wt% chrysotile asbestos. Analyses indicate that trace levels of chrysotile were distributed with the dust radially to distances greater than 0.75 km from Ground Zero. The chrysotile content of the dust is variable and may indicate that chrysotile asbestos was not distributed uniformly during the three collapse events.

Attack tolerance of correlated time-varying social networks with well-defined communities

NASA Astrophysics Data System (ADS)

Sur, Souvik; Ganguly, Niloy; Mukherjee, Animesh

2015-02-01

In this paper, we investigate the efficiency and the robustness of information transmission for real-world social networks, modeled as time-varying instances, under targeted attack in shorter time spans. We observe that these quantities are markedly higher than that of the randomized versions of the considered networks. An important factor that drives this efficiency or robustness is the presence of short-time correlations across the network instances which we quantify by a novel metric the-edge emergence factor, denoted as ξ. We find that standard targeted attacks are not effective in collapsing this network structure. Remarkably, if the hourly community structures of the temporal network instances are attacked with the largest size community attacked first, the second largest next and so on, the network soon collapses. This behavior, we show is an outcome of the fact that the edge emergence factor bears a strong positive correlation with the size ordered community structures.

Stabilisation and humanitarian access in a collapsed state: the Somali case.

PubMed

Menkhaus, Ken

2010-10-01

Somalia today is the site of three major threats: the world's worst humanitarian crisis; the longest-running instance of complete state collapse; and a robust jihadist movement with links to Al-Qa'ida. External state-building, counter-terrorism and humanitarian policies responding to these threats have worked at cross-purposes. State-building efforts that insist humanitarian relief be channelled through the nascent state in order to build its legitimacy and capacity undermine humanitarian neutrality when the state is a party to a civil war. Counter-terrorism policies that seek to ensure that no aid benefits terrorist groups have the net effect of criminalising relief operations in countries where poor security precludes effective accountability. This paper argues that tensions between stabilisation and humanitarian goals in contemporary Somalia reflect a long history of politicisation of humanitarian operations in the country. © 2010 The Author(s). Journal compilation © Overseas Development Institute, 2010.

SNEWS The SuperNova Early Warning System

NASA Astrophysics Data System (ADS)

SNEWS Group

2005-06-01

SNEWS is a cooperative effort between the world's neutrino detection experiments to spread the news that a star in our galaxy has just experienced a core-collapse and is about to be seen as a Supernova. This project exploits the ˜hours time difference between neutrinos promptly escaping the nascent supernova and photons originating when the shock wave breaks through the stellar photosphere, to give the world a chance to get ready to observe such an exciting event at the earliest possible time. A coincidence trigger between experiments is used to eliminate potential local false alarms, allowing a rapid, automated alert. SNEWS is currently operational and ready, and this poster presents the procedures in use.

Method and apparatus for simulating gravitational forces on a living organism

NASA Technical Reports Server (NTRS)

Thornton, W. E. (Inventor)

1983-01-01

A method and apparatus for simulating gravitational forces on a living organism wherein a series of negative pressures are externally applied to successive length-wise sections of a lower limb of the organism. The pressures decreasing progressively with distance of said limb sections from the heart of the organism. A casing defines a chamber adapted to contain the limb of the organism and is rigidified to resist collapse upon the application of negative pressures to the interior of the chamber. Seals extend inwardly from the casing for effective engagement with the limb of the organism and, in cooperation with the limb, subdivide the chamber into a plurality of compartments each in negative pressure communicating relation with the limb.

Steady finite-Reynolds-number flows in three-dimensional collapsible tubes

NASA Astrophysics Data System (ADS)

Hazel, Andrew L.; Heil, Matthias

2003-07-01

A fully coupled finite-element method is used to investigate the steady flow of a viscous fluid through a thin-walled elastic tube mounted between two rigid tubes. The steady three-dimensional Navier Stokes equations are solved simultaneously with the equations of geometrically nonlinear Kirchhoff Love shell theory. If the transmural (internal minus external) pressure acting on the tube is sufficiently negative then the tube buckles non-axisymmetrically and the subsequent large deformations lead to a strong interaction between the fluid and solid mechanics. The main effect of fluid inertia on the macroscopic behaviour of the system is due to the Bernoulli effect, which induces an additional local pressure drop when the tube buckles and its cross-sectional area is reduced. Thus, the tube collapses more strongly than it would in the absence of fluid inertia. Typical tube shapes and flow fields are presented. In strongly collapsed tubes, at finite values of the Reynolds number, two ’jets‘ develop downstream of the region of strongest collapse and persist for considerable axial distances. For sufficiently high values of the Reynolds number, these jets impact upon the sidewalls and spread azimuthally. The consequent azimuthal transport of momentum dramatically changes the axial velocity profiles, which become approximately uTheta-shaped when the flow enters the rigid downstream pipe. Further convection of momentum causes the development of a ring-shaped velocity profile before the ultimate return to a parabolic profile far downstream.

The origin of mean arterial and jugular venous blood pressures in giraffes.

PubMed

Mitchell, Graham; Maloney, Shane K; Mitchell, Duncan; Keegan, D James

2006-07-01

Using a mechanical model of the giraffe neck and head circulation consisting of a rigid, ascending, 'carotid' limb, a 'cranial' circulation that could be rigid or collapsible, and a descending, 'jugular' limb that also could be rigid or collapsible, we have analyzed the origin of the high arterial and venous pressures in giraffe, and whether blood flow is assisted by a siphon. When the tubes were rigid and the 'jugular' limb exit was lower than the 'carotid' limb entrance a siphon operated, 'carotid' hydrostatic pressures became more negative, and flow was 3.3 l min(-1) but ceased when the 'cranial' and 'jugular' limbs were collapsible or when the 'jugular' limb was opened to the atmosphere. Pumping water through the model produced positive pressures in the 'carotid' limb similar to those found in giraffe. Applying an external 'tissue' pressure to the 'jugular' tube during pump flow produced the typical pressures found in the jugular vein in giraffe. Constriction of the lowest, 'jugular cuff', portion of the 'jugular' limb showed that the cuff may augment the orthostatic reflex during head raising. Except when all tubes were rigid, pressures were unaffected by a siphon. We conclude that mean arterial blood pressure in giraffes is a consequence of the hydrostatic pressure generated by the column of blood in the neck, that tissue pressure around the collapsible jugular vein produces the known jugular pressures, and that a siphon does not assist flow through the cranial circulation.

Pressure-jump small-angle x-ray scattering detected kinetics of staphylococcal nuclease folding.

PubMed Central

Woenckhaus, J; Köhling, R; Thiyagarajan, P; Littrell, K C; Seifert, S; Royer, C A; Winter, R

2001-01-01

The kinetics of chain disruption and collapse of staphylococcal nuclease after positive or negative pressure jumps was monitored by real-time small-angle x-ray scattering under pressure. We used this method to probe the overall conformation of the protein by measuring its radius of gyration and pair-distance-distribution function p(r) which are sensitive to the spatial extent and shape of the particle. At all pressures and temperatures tested, the relaxation profiles were well described by a single exponential function. No fast collapse was observed, indicating that the rate limiting step for chain collapse is the same as that for secondary and tertiary structure formation. Whereas refolding at low pressures occurred in a few seconds, at high pressures the relaxation was quite slow, approximately 1 h, due to a large positive activation volume for the rate-limiting step for chain collapse. A large increase in the system volume upon folding implies significant dehydration of the transition state and a high degree of similarity in terms of the packing density between the native and transition states in this system. This study of the time-dependence of the tertiary structure in pressure-induced folding/unfolding reactions demonstrates that novel information about the nature of protein folding transitions and transition states can be obtained from a combination of small-angle x-ray scattering using high intensity synchrotron radiation with the high pressure perturbation technique. PMID:11222312

Could a Mathematics Student Have Prevented the Collapse of the Atlanto-Scandian Herring?

ERIC Educational Resources Information Center

Sigurdsson, Thorir

2006-01-01

Herring in the ocean between Iceland and Norway was one of the largest fish stocks in the world until the fishery crashed in the late 1960s. The catch in 1971 was only 20 thousand metric tons in contrast with the record of 2 million tons in 1966 and the spawning stock declined from 10 million tons to 10 thousand tons in 20 years. After 25 years of…

The ROK Army’s Role When North Korea Collapses Without a War with the ROK

DTIC Science & Technology

2001-02-01

produced large amounts of biological and chemical weapons. In addition, North Korea continues to develop nuclear weapons and missile technology and export...process. 6. Security and safe disposal of WMD. This includes research, production and storage facilities for nuclear, biological and chemical weapons...Publishers, 1989. Naisbitt, John . Megatrends Asia: Eight Asian Megatrends That Are Reshaping Our World, New York: Simon and Schuster. 1996. The New

KSC-2014-3800

NASA Image and Video Library

2014-09-11

Cape Canaveral, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, the 9/11 memorial is shown before a ceremony held by Kennedy’s Fire and Rescue personnel. Kennedy Fire and Rescue Services commemorated the 13th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Photo credit: Jim Grossmann

KSC-2014-3801

NASA Image and Video Library

2014-09-11

Cape Canaveral, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, the 9/11 memorial emblem is shown during a ceremony held by Kennedy’s Fire and Rescue personnel. Kennedy Fire and Rescue Services commemorated the 13th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Photo credit: Jim Grossmann

Cuba Adrift in a Postcommunist World

DTIC Science & Technology

1992-01-01

Union’s collapse. Once the embargo is dismantled and U.S. business interests develop a stake in Cuba, reimp -tion of the embargo would become virtually ...34zero option" this year- a virtual cut-off of imports from the former Soviet Union, forcing them to endure even greater austerity, privations, and...black market and underground capitalist activities, but also crimes of violence that were virtually unheard of in the past. As a consequence, the

Robust Intelligence (RI) Under Uncertainty: Mathematical Foundations of Autonomous Hybrid (Human-Machine-Robot) Teams, Organizations and Systems

DTIC Science & Technology

2013-01-01

seeds of chaos. Stability and internal peace bring prosperity; prosperity causes population increase. Demographic growth leads to overpopulation ... overpopulation causes lower wages, higher land rents, and falling per-capita incomes … [Eventually, the] collapse of order brings … famine, war...one of the most innovative, competitive and largest firms in the world (e.g., Investors Business Daily, 2000, 10/31; Bloomberg’s Businessweek, 2001, 9

Conceptual design proposal: HUGO global range/mobility transport aircraft

NASA Technical Reports Server (NTRS)

Johnston, Tom; Perretta, Dave; Mcbane, Doug; Morin, Greg; Thomas, Greg; Woodward, Joe; Gulakowski, Steve

1993-01-01

With the collapse of the former Soviet Union and the emergence of the United Nations actively pursuing a peace keeping role in world affairs, the United States has been forced into a position as the world's leading peace enforcer. It is still a very dangerous world with seemingly never ending ideological, territorial, and economic disputes requiring the U.S. to maintain a credible deterrent posture in this uncertain environment. This has created an urgent need to rapidly transport large numbers of troops and equipment from the continental United States (CONUS) to any potential world trouble spot by means of a global range/mobility transport aircraft. The most recent examples being Operation Desert Shield/Storm and Operation Restore Hope. To meet this challenge head-on, a request for proposal (RFP) was developed and incorporated into the 1992/1993 AIAA/McDonnell Douglas Corporation Graduate Team Aircraft Design Competition. The RFP calls for the conceptual design and justification of a large aircraft capable of power projecting a significant military force without surface transportation reliance.

Cod Collapse and the Climate in the North Atlantic

NASA Astrophysics Data System (ADS)

Meng, K. C.; Oremus, K. L.; Gaines, S.

2014-12-01

Effective fisheries management requires forecasting population changes. We find a negative relationship between the North Atlantic Oscillation (NAO) index and subsequently surveyed biomass and catch of Atlantic cod, Gadus morhua, off the New England coast. A 1-unit NAO increase is associated with a 17% decrease in surveyed biomass of age-1 cod the following year. This relationship persists as the cod mature, such that observed NAO can be used to forecast future adult biomass. We also document that an NAO event lowers catch for up to 15 years afterward. In contrast to forecasts by existing stock assessment models, our NAO-driven statistical model successfully hindcasts the recent collapse of New England cod fisheries following strong NAO events in 2007 and 2008 (see figure). This finding can serve as a template for forecasting other fisheries affected by climatic conditions.

Negative-tone development of photoresists in environmentally friendly silicone fluids

NASA Astrophysics Data System (ADS)

Ouyang, Christine Y.; Lee, Jin-Kyun; Ober, Christopher K.

2012-03-01

The large amount of organic solvents and chemicals that are used in today's microelectronic fabrication process can lead to environmental, health and safety hazards. It is therefore necessary to design new materials and new processes to reduce the environmental impact of the lithographic process. In addition, as the feature sizes decrease, other issues such as pattern collapse, which is related to the undesirable high surface tension of the developers and rinse liquids, can occur and limit the resolution. In order to solve these issues, silicone fluids are chosen as alternative developing solvents in this paper. Silicone fluids, also known as linear methyl siloxanes, are a class of mild, non-polar solvents that are non-toxic, not ozone-depleting, and contribute little to global warming. They are considered as promising developers because of their environmental-friendliness and their unique physical properties such as low viscosity and low surface tension. Recently, there have been emerging interests in negative-tone development (NTD) due to its better ability in printing contact holes and trenches. It is also found that the performance of negative-tone development is closely related to the developing solvents. Silicone fluids are thus promising developers for NTD because of their non-polar nature and high contrast negative-tone images are expected with chemical amplification photoresists due to the high chemical contrast of chemical amplification. We have previously shown some successful NTD with conventional photoresists such as ESCAP in silicone fluids. In this paper, another commercially available TOK resist was utilized to study the NTD process in silicone fluids. Because small and non-polar molecules are intrinsically soluble in silicone fluids, we have designed a molecular glass resist for silicone fluids. Due to the low surface tension of silicone fluids, we are able achieve high aspect-ratio, high-resolution patterns without pattern collapse.

Response to a combination of oxygen and a hypnotic as treatment for obstructive sleep apnoea is predicted by a patient's therapeutic CPAP requirement.

PubMed

Landry, Shane A; Joosten, Simon A; Sands, Scott A; White, David P; Malhotra, Atul; Wellman, Andrew; Hamilton, Garun S; Edwards, Bradley A

2017-08-01

Upper airway collapsibility predicts the response to several non-continuous positive airway pressure (CPAP) interventions for obstructive sleep apnoea (OSA). Measures of upper airway collapsibility cannot be easily performed in a clinical context; however, a patient's therapeutic CPAP requirement may serve as a surrogate measure of collapsibility. The present work aimed to compare the predictive use of CPAP level with detailed physiological measures of collapsibility. Therapeutic CPAP levels and gold-standard pharyngeal collapsibility measures (passive pharyngeal critical closing pressure (P crit ) and ventilation at CPAP level of 0 cmH 2 O (V passive )) were retrospectively analysed from a randomized controlled trial (n = 20) comparing the combination of oxygen and eszopiclone (treatment) versus placebo/air control. Responders (9/20) to treatment were defined as those who exhibited a 50% reduction in apnoea/hypopnoea index (AHI) plus an AHI<15 events/h on-therapy. Responders to treatment had a lower therapeutic CPAP requirement compared with non-responders (6.6 (5.4-8.1)  cmH 2 O vs 8.9 (8.4-10.4) cmH 2 O, P = 0.007), consistent with their reduced collapsibility (lower P crit , P = 0.017, higher V passive P = 0.025). Therapeutic CPAP level provided the highest predictive accuracy for differentiating responders from non-responders (area under the curve (AUC) = 0.86 ± 0.9, 95% CI: 0.68-1.00, P = 0.007). However, both P crit (AUC = 0.83 ± 0.11, 95% CI: 0.62-1.00, P = 0.017) and V passive (AUC = 0.77 ± 0.12, 95% CI: 0.53-1.00, P = 0.44) performed well, and the difference in AUC for these three metrics was not statistically different. A therapeutic CPAP level ≤8 cmH 2 O provided 78% sensitivity and 82% specificity (positive predictive value = 78%, negative predictive value = 82%) for predicting a response to these therapies. Therapeutic CPAP requirement, as a surrogate measure of pharyngeal collapsibility, predicts the response to non-anatomical therapy (oxygen and eszopiclone) for OSA. © 2017 Asian Pacific Society of Respirology.

Korean Unification and United States Security Alternatives in Northeast Asia

DTIC Science & Technology

1993-06-01

subterfuge or the failure of the respective government to deal effectively with political, social, or economic crises as they develop . Such a collapse would...revolutionary power will suffer a fundamental defeat, and the American invaders will run more rampant, and have negative effects for the entire Far East.46 In...100 C. KOREA AND NORTHEAST ASIA IN THE GLOBAL CONTEXT ......... 102 VII. CONCLUSION

[Latin America and the crisis (points for the balance of a decade)].

PubMed

Lopez Maya, M

1990-01-01

The decade of the 1980s was catastrophic for the countries of Latin America because of profound transformations in the world economy, which started in the 1970s, the wilting of the state development programs that were imposed after World War II, and the collapse of socialism with the incipient transition to market economies. The crisis started because of the erosion of the world economic system as constituted under the Bretton Woods agreement; the drastic drop in the economic growth of market economies; the increased costs of living and the deterioration of the environment; the decrease in industrial capacity; and the emergence of transnationalization of production. In Latin America, the economic models that had been in place without solving underdevelopment became even more obsolete (import substitution, internal trade, and the role of the state). The crisis of socialism and the rapprochement of eastern European countries to western Europe also affected Latin America (e.g., Germany cancelled 30 mine exploration projects in Bolivia due to investments in East Germany). The structural readjustment policies of the International Monetary Fund and the World Bank resulted in currency devaluations, redistribution of government funds, elimination of various subsidies, reduction of public debt and social expenditures, reduction of public employment, and payment of external debt. The result was more inflation (in Bolivia, Brazil, Peru, and Argentina, inflation rates were 683.7%, 157.1%, 100.1%, and 326.2%, respectively, between 1980 and 1986), unemployment, and poverty in the lost decade of the 1980s. After 1982, state expenditures on roads, education, hospitals, and nutrition declined by 40% in Mexico. Even though most countries returned to democracy in the region, this was at the cost of the increased role of the military and the transnationals. The grand parties collapsed and in Venezuela, Mexico, and Colombia authoritarian tendencies survived into the 1970s degrading democracy. The states' socioeconomic regulatory role has to be redefined.

3-D Waveform Modeling of the 11 September 2001 World Trade Center Collapse Events in New York City

NASA Astrophysics Data System (ADS)

Yoo, S.; Rhie, J.; Kim, W.

2010-12-01

The seismic signals from collapse of the twin towers of World Trade Center (WTC), NYC were well recorded by the seismographic stations in the northeastern United States. The building collapse can be represented by a vertical single force which does not generate tangential component seismic signals during the source process. The waveforms recorded by the Basking Ridge, NJ (BRNJ) station located due west of the WTC site show that the amplitude on tangential component is negligible and indicates that a vertical single force assumption is valid and the velocity structure is more or less homogeneous along the propagation path. However, 3-component seismograms recorded at Palisades, NY (PAL), which is located 33.8 km due north of the WTC site along the Hudson River (azimuth = 15.2°), show abnormal features. The amplitude on tangential component is larger than on vertical- or on radial-component. This observation may be attributable to the complex energy conversion between Rayleigh and Love waves due to the strong low velocity anomaly associated with unconsolidated sediments under the Hudson River. To test the effects of the low velocity anomaly on the enhanced amplitude in tangential component, we developed a 3D velocity model by considering local geology such as unconsolidated sediment layer, Palisades sill, Triassic sandstone, and crystalline basement and simulated waveforms at PAL. The preliminary synthetic results show that 3D velocity structure can significantly enhance the amplitude in tangential component but it is not as large as the observation. Although a more precise 3D model is required to better explain the observations, our results confirm that the low velocity layer under the Hudson River can enhance the amplitude in tangential component at PAL. This result suggests that a good understanding of the amplitude enhancements for specific event-site pairs may be important to evaluate seismic hazard of metropolitan New York City.

Cultural responses to climate change during the late Holocene.

PubMed

deMenocal, P B

2001-04-27

Modern complex societies exhibit marked resilience to interannual-to- decadal droughts, but cultural responses to multidecadal-to-multicentury droughts can only be addressed by integrating detailed archaeological and paleoclimatic records. Four case studies drawn from New and Old World civilizations document societal responses to prolonged drought, including population dislocations, urban abandonment, and state collapse. Further study of past cultural adaptations to persistent climate change may provide valuable perspective on possible responses of modern societies to future climate change.

From Easter Island to coated coronary stents: a remarkable saga.

PubMed

Cantwell, John D

2008-01-01

Easter Island, even though it's in the middle of nowhere, is indeed a piece of the continent, as John Donne alluded to. In addition to contributing rapamycin to the medical field, the island is an example to the whole world of the consequences of affluent lifestyles, tribal wars, and ignorance of ecology. Jared Diamond expressed these thoughts best in his book, "Collapse:" The parallels between Easter Island and the whole modern world are chillingly obvious... All countries on earth today share resources and affect each other just as did Easter's dozen clans. Polynesian Easter Island was as isolated in the Pacific Ocean as the Earth is today in space. People see the collapse of Easter Island 's society as a metaphor; a worst-case scenario, for what may lie ahead for us in our own future. Some veteran Easter Island archaeologists like Claudio Cristina feel that Diamond's views are overly simplistic, commenting that he only spent a week on the island (versus 30 years for Cristina). Predatory Polynesian rats, earthquakes, tsunamis, variations in rainfall, diseases introduced by European sailing ships, could all have contributed to the near-demise of Easter Island. Tribal wars certainly didn't help, nor did slave-raiding parties from Peru. Only the eyes of the moai (Fig. 5) have seen it all, but the statues remain silent, as they have for over 1,000 years.

Exposure and Human Health Evaluation of Airborne Pollution ...

EPA Pesticide Factsheets

Following the collapse of the World Trade Center towers on September 11, 2001, New York State and Federal agencies initiated numerous air monitoring activities to better understand the ongoing impact of emissions from the disaster. This report focuses on these air measurement data, evaluating them in terms of what is typical for New York City or general urban background and interpreting it with regard to the potential for human health consequences. The report does not evaluate exposures possibly faced by rescue or clean-up workers and briefly discusses past and current indoor monitoring efforts. The analysis in this report supports three general findings: 1) Persons exposed to the extremely high levels of ambient particulate matter and its components during the collapse of the World Trade Center towers and for several hours afterwards were likely to be at risk for immediate acute (and possibly chronic) respiratory and other types (e.g., cardiovascular) of symptoms. 2) The first measurements of some of the contaminants were on September 14, while other contaminants were not measured until September 23. Available data suggest that the concentrations within and near Ground Zero were likely to be highest in the few days following September 11. Because there are only limited data on these critical few days, exposures and potential health impacts cannot be evaluated with certainty for this time period. 3) Except for exposures on September 11 and possibly d

The Supernova Early Warning System (SNEWS)

NASA Astrophysics Data System (ADS)

Habig, A.; SNEWS Collaboration

2005-05-01

SNEWS is a cooperative effort between the world's neutrino detection experiments to spread the news that a star in our galaxy has just experienced a core-collapse event and is about to become a Type-II Supernova. This project exploits the ˜hours time difference between neutrinos promptly escaping the nascent supernova and photons which originate when the shock wave breaks through the stellar photosphere, to give the world a chance to get ready to observe such an exciting event at the earliest possible time. A coincidence trigger between experiments is used to eliminate potential local false alarms, allowing a rapid, automated alert. SNEWS is currently operational and ready, and this poster presents the procedures in use. SNEWS work is supported by NSF collaborative grant #0302166.

Issues and strategies in the DNA identification of World Trade Center victims.

PubMed

Brenner, C H; Weir, B S

2003-05-01

Identification of the nearly 3000 victims of the World Trade Center attack, represented by about 15,000 body parts, rests heavily on DNA. Reference DNA profiles are often from relatives rather than from the deceased themselves. With so large a set of victims, coincidental similarities between non-relatives abound. Therefore considerable care is necessary to succeed in correlating references with correct victims while avoiding spurious assignments. Typically multiple relatives are necessary to establish the identity of a victim. We describe a 3-stage paradigm--collapse, screen, test--to organize the work of sorting out the identities. Inter alia we present a simple and general formula for the likelihood ratio governing practically any potential relationship between two DNA profiles.

World-size global markets lead to economic instability.

PubMed

Louzoun, Yoram; Solomon, Sorin; Goldenberg, Jacob; Mazursky, David

2003-01-01

Economic and cultural globalization is one of the most important processes humankind has been undergoing lately. This process is assumed to be leading the world into a wealthy society with a better life. However, the current trend of globalization is not unprecedented in human history, and has had some severe consequences in the past. By applying a quantitative analysis through a microscopic representation we show that globalization, besides being unfair (with respect to wealth distribution), is also unstable and potentially dangerous as one event may lead to a collapse of the system. It is proposed that the optimal solution in controlling the unwanted aspects and enhancing the advantageous ones lies in limiting competition to large subregions, rather than making it worldwide.

ASSESSMENT OF DIOXIN INHALATION EXPOSURES AND ...

EPA Pesticide Factsheets

In the days following the September 11, 2001, terrorist attack on New York City's World Trade Center (WTC) towers, EPA, other federal agencies, and New York City and New York State public health and environmental authorities initiated numerous air monitoring activities to better understand the ongoing impact of emissions from that disaster. Using these data, EPA conducted an inhalation exposure and human health risk assessment. The overall evaluation focused on particulate matter, metals, polychlorinated biphenyls, dioxin-like compounds, asbestos, and volatile organic compounds. This paper reports on the analysis of dioxin-like compounds only.Lorber, M. 2003. Assessment of Dioxin Inhalation Exposures and Potential Health Impacts Following the Collapse of the World Trade Center Towers. Organohalogen Compounds 63 (no page numbers). journal article

Buckling of Elastomeric Beams Enables Actuation of Soft Machines

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

Yang, Dian; Mosadegh, Bobak; Ainla, Alar

2015-09-21

Soft, pneumatic actuators that buckle when interior pressure is less than exterior provide a new mechanism of actuation. Upon application of negative pneumatic pressure, elastic beam elements in these actuators undergo reversible, cooperative collapse, and generate a rotational motion. These actuators are inexpensive to fabricate, lightweight, easy to control, and safe to operate. They can be used in devices that manipulate objects, locomote, or interact cooperatively with humans.

Constant proportion harvest policies: dynamic implications in the Pacific halibut and Atlantic cod fisheries.

PubMed

Yakubu, Abdul-Aziz; Li, Nianpeng; Conrad, Jon M; Zeeman, Mary-Lou

2011-07-01

Overfishing, pollution and other environmental factors have greatly reduced commercially valuable stocks of fish. In a 2006 Science article, a group of ecologists and economists warned that the world may run out of seafood from natural stocks if overfishing continues at current rates. In this paper, we explore the interaction between a constant proportion harvest policy and recruitment dynamics. We examine the discrete-time constant proportion harvest policy discussed in Ang et al. (2009) and then expand the framework to include stock-recruitment functions that are compensatory and overcompensatory, both with and without the Allee effect. We focus on constant proportion policies (CPPs). CPPs have the potential to stabilize complex overcompensatory stock dynamics, with or without the Allee effect, provided the rates of harvest stay below a threshold. If that threshold is exceeded, CPPs are known to result in the sudden collapse of a fish stock when stock recruitment exhibits the Allee effect. In case studies, we analyze CPPs as they might be applied to Gulf of Alaska Pacific halibut fishery and the Georges Bank Atlantic cod fishery based on harvest rates from 1975 to 2007. The best fit models suggest that, under high fishing mortalities, the halibut fishery is vulnerable to sudden population collapse while the cod fishery is vulnerable to steady decline to zero. The models also suggest that CPP with mean harvesting levels from the last 30 years can be effective at preventing collapse in the halibut fishery, but these same policies would lead to steady decline to zero in the Atlantic cod fishery. We observe that the likelihood of collapse in both fisheries increases with increased stochasticity (for example, weather variability) as predicted by models of global climate change. Copyright © 2011 Elsevier Inc. All rights reserved.

Use of laboratory geophysical and geotechnical investigation methods to characterize gypsum rich soils

NASA Astrophysics Data System (ADS)

Bhamidipati, Raghava A.

Gypsum rich soils are found in many parts of the world, particularly in arid and semi-arid regions. Most gypsum occurs in the form of evaporites, which are minerals that precipitate out of water due to a high rate of evaporation and a high mineral concentration. Gypsum rich soils make good foundation material under dry conditions but pose major engineering hazards when exposed to water. Gypsum acts as a weak cementing material and has a moderate solubility of about 2.5 g/liter. The dissolution of gypsum causes the soils to undergo unpredictable collapse settlement leading to severe structural damages. The damages incur heavy financial losses every year. The objective of this research was to use geophysical methods such as free-free resonant column testing and electrical resistivity testing to characterize gypsum rich soils based on the shear wave velocity and electrical resistivity values. The geophysical testing methods could provide quick, non-intrusive and cost-effective methodologies to screen sites known to contain gypsum deposits. Reconstituted specimens of ground gypsum and quartz sand were prepared in the laboratory with varying amounts of gypsum and tested. Additionally geotechnical tests such as direct shear strength tests and consolidation tests were conducted to estimate the shear strength parameters (drained friction angle and cohesion) and the collapse potential of the soils. The effect of gypsum content on the geophysical and geotechnical parameters of soil was of particular interest. It was found that gypsum content had an influence on the shear wave velocity but had minimal effect on electrical resistivity. The collapsibility and friction angle of the soil increased with increase in gypsum. The information derived from the geophysical and geotechnical tests was used to develop statistical design equations and correlations to estimate gypsum content and soil collapse potential.

Was Miyakejima undergoing subsidence before the 2000 caldera collapse? JERS1 InSAR results: 1992-1998

NASA Astrophysics Data System (ADS)

Furuya, M.

2003-12-01

Miyakejima volcano is a basaltic strato volcano island on the eastern edge of the Philippine Sea Plate, and was undergoing a number of eruption activities over the past centuries. In July-August 2000, the Miyakejima volcano underwent a caldera collapse, prompting many modern geodetic and geophysical measurements (e.g., Geshi et al. 2002; Furuya et al. 2003). The observation results on the pre-caldera-collapse stages are, however, limitted. Were there any precursory secular subsidence before the collapse? Though Miyazaki (1990) reported a secular subsidence at the Miyakejima, using leveling technique, there are no documented reports, to my knowledge, which employed radar interferometry to examine the ground displacements at Miyakejima. Here I will report on the results derived from the radar interferometry at Miyakejima volcano. I chose JERS-1 data (L-band HH) for the analysis, so that I could get rid of the loss of coherence; most of the Miyakejima is covered with vegetation. To remove the topographic fringes as well as to re-estimate the spatial baseline data (Rosen et al. 1996), I employed 10-meter resolution digital elevation map derived by Geographical Survey Institute, Japan. I could generate 24 differential interferograms at the time of writing this text. However, I do not yet recognize any significant "signals" that can be discriminated with the atmospheric "noise". There appears to be no specific subsidence pattern, which are detected in a number of other volcanos in the world (e.g., Lu et al. 2002; Yarai et al. 2002; Okuyama et al. 2002). I am going to show a stacked interferogram like that in Fujiwara et al. (1998) and to examine the existence of volcanic signals.

Cardiorespiratory interactions and blood flow generation during cardiac arrest and other states of low blood flow.

PubMed

Sigurdsson, Gardar; Yannopoulos, Demetris; McKnite, Scott H; Lurie, Keith G

2003-06-01

Recent advances in cardiopulmonary resuscitation have shed light on the importance of cardiorespiratory interactions during shock and cardiac arrest. This review focuses on recently published studies that evaluate factors that determine preload during chest compression, methods that can augment preload, and the detrimental effects of hyperventilation and interrupting chest compressions. Refilling of the ventricles, so-called ventricular preload, is diminished during cardiovascular collapse and resuscitation from cardiac arrest. In light of the potential detrimental effects and challenges of large-volume fluid resuscitations, other methods have increasing importance. During cardiac arrest, active decompression of the chest and impedance of inspiratory airflow during the recoil of the chest work by increasing negative intrathoracic pressure and, hence, increase refilling of the ventricles and increase cardiac preload, with improvement in survival. Conversely, increased frequency of ventilation has detrimental effects on coronary perfusion pressure and survival rates in cardiac arrest and severe shock. Prolonged interruption of chest compressions for delivering single-rescuer ventilation or analyzing rhythm before shock delivery is associated with decreased survival rate. Cardiorespiratory interactions are of profound importance in states of cardiovascular collapse in which increased negative intrathoracic pressure during decompression of the chest has a favorable effect and increased intrathoracic pressure with ventilation has a detrimental effect on survival rate.

Reductions in Circulating Endocannabinoid Levels in Individuals with Post-Traumatic Stress Disorder Following Exposure to the World Trade Center Attacks

PubMed Central

Hill, Matthew N.; Bierer, Linda M.; Makotkine, Iouri; Golier, Julia A.; Galea, Sandro; McEwen, Bruce S.; Hillard, Cecilia J.; Yehuda, Rachel

2013-01-01

Endocannabinoid (eCB) signaling has been identified as a modulator of adaptation to stress, and is integral to basal and stress-induced glucocorticoid regulation. Furthermore, interactions between eCBs and glucocorticoids have been shown to be necessary for the regulation of emotional memories, suggesting that eCB function may relate to the development of post-traumatic stress disorder (PTSD). To examine this, plasma eCBs were measured in a sample (n=46) drawn from a population-based cohort selected for physical proximity to the World Trade Center (WTC) at the time of the 9/11 attacks. Participants received a structured diagnostic interview and were grouped according to whether they met diagnostic criteria for PTSD (no PTSD, n=22; lifetime diagnosis of PTSD = 24). eCB content (2-arachidonoylglycerol (2-AG) and anandamide (AEA)) and cortisol were measured from 8 a.m. plasma samples. Circulating 2-AG content was significantly reduced among individuals meeting diagnostic criteria for PTSD. The effect of reduced 2-AG content in PTSD remained significant after controlling for the stress of exposure to the WTC collapse, gender, depression and alcohol abuse. There were no significant group differences for AEA or cortisol levels; however, across the whole sample AEA levels positively correlated with circulating cortisol, and AEA levels exhibited a negative relationship with the degree of intrusive symptoms within the PTSD sample. This report shows that PTSD is associated with a reduction in circulating levels of the eCB 2-AG. Given the role of 2-AG in the regulation of the stress response, these data support the hypothesis that deficient eCB signaling may be a component of the glucocorticoid dysregulation associated with PTSD. The negative association between AEA levels and intrusive symptoms is consistent with animal data indicating that reductions in AEA promote retention of aversive emotional memories. Future work will aim to replicate these findings and extend their relevance to clinical pathophysiology, as well as to neuroendocrine and molecular markers of PTSD. PMID:24035186

Optical mapping of prefrontal brain connectivity and activation during emotion anticipation.

PubMed

Wang, Meng-Yun; Lu, Feng-Mei; Hu, Zhishan; Zhang, Juan; Yuan, Zhen

2018-09-17

Accumulated neuroimaging evidence shows that the dorsal lateral prefrontal cortex (dlPFC) is activated during emotion anticipation. The aim of this work is to examine the brain connectivity and activation differences in dlPFC between the positive, neutral and negative emotion anticipation by using functional near-infrared spectroscopy (fNIRS). The hemodynamic responses were first assessed for all subjects during the performance of various emotion anticipation tasks. And then small-world analysis was performed, in which the small-world network indicators including the clustering coefficient, average path length, average node degree, and measure of small-world index were calculated for the functional brain networks associated with the positive, neutral and negative emotion anticipation, respectively. We discovered that compared to negative and neutral emotion anticipation, the positive one exhibited enhanced brain activation in the left dlPFC. Although the functional brain networks for the three emotion anticipation cases manifested the small-world properties regarding the clustering coefficient, average path length, average node degree, and measure of small-world index, the positive one showed significantly higher clustering coefficient and shorter average path length than those from the neutral and negative cases. Consequently, the small-world network indicators and brain activation in dlPPC were able to distinguish well between the positive, neutral and negative emotion anticipation. Copyright © 2018 Elsevier B.V. All rights reserved.

Operation Enduring Freedom. Joint Center for Operational Analysis Journal, Volume 11, Issue 3, Fall 2009

DTIC Science & Technology

2009-01-01

began a period known as the Great Game , which was a century and a half long competition for Afghanistan by Britain and Russia. Each of the countries...It is yet to be determined whether or not the United States is capable of sustaining initial success, or if the Great Game will continue...showed Malik Noorafzal video footage of the World Trade Center towers collapsing. He had never seen this and it made a deep impression. He had heard

Bellerophon

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

Lingerfelt, Eric J; Messer, II, Otis E

2017-01-02

The Bellerophon software system supports CHIMERA, a production-level HPC application that simulates the evolution of core-collapse supernovae. Bellerophon enables CHIMERA's geographically dispersed team of collaborators to perform job monitoring and real-time data analysis from multiple supercomputing resources, including platforms at OLCF, NERSC, and NICS. Its multi-tier architecture provides an encapsulated, end-to-end software solution that enables the CHIMERA team to quickly and easily access highly customizable animated and static views of results from anywhere in the world via a cross-platform desktop application.

Operating Below Crush Depth: The Formation, Evolution, and Collapse of the Imperial Japanese Navy Submarine Force in World War II

DTIC Science & Technology

2011-06-10

Subamrine, Medium) LCDR Lieutenant Commander LT Lieutenant NM Nautical Mile RADM Rear Admiral ST Sen- Taka (Submarine, High Speed) STo Sen-Toku...Special Submarine) STS Sen- Taka -Sho (Submarine, High Speed(Victory)) USS United States Ship VADM Vice Admiral 1 CHAPTER 1 INTRODUCTION On...Kirai-Sen meaning Mine-Layer, KT for Kai-Toku-Chu meaning Medium, Special Submarine, ST for Sen- Taka meaning Submarine, High speed, STo for Sen Toku

KSC-2014-3807

NASA Image and Video Library

2014-09-11

Cape Canaveral, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel salute or stand at attention as the American flag is raised during a ceremony held by Kennedy’s Fire and Rescue personnel. Kennedy Fire and Rescue Services commemorated the 13th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Photo credit: Jim Grossmann

KSC-2014-3806

NASA Image and Video Library

2014-09-11

Cape Canaveral, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel stand at attention as the American flag is raised during a ceremony held by Kennedy’s Fire and Rescue personnel. Kennedy Fire and Rescue Services commemorated the 13th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Photo credit: Jim Grossmann

KSC-2014-3808

NASA Image and Video Library

2014-09-11

Cape Canaveral, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel salute or stand at attention as the American flag is raised during a ceremony held by Kennedy’s Fire and Rescue personnel. Kennedy Fire and Rescue Services commemorated the 13th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Photo credit: Jim Grossmann

KSC-2014-3805

NASA Image and Video Library

2014-09-11

Cape Canaveral, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Gabe Wingard and Steve Dudgeon, both with NASA's Protective Services, fold the commemorative flag during a ceremony held by Kennedy’s Fire and Rescue personnel. Kennedy Fire and Rescue Services commemorated the 13th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Photo credit: Jim Grossmann

Unfinished Business: A Framework for Peace in the Great Lakes (Africa Security Brief, Number 21, July 2012)

DTIC Science & Technology

2012-07-01

where they are levied with fees and re-exported, often by lo- cal businesses. This has become a significant source of economic activity and growth ...Policies for Growth with a Focus on Household Enterprises, Rwanda Economic Update 2 nd Edition, (Washington, DC: World Bank, November 2011), 3. 9 Ivan...extended instability has also led to a collapse of basic social services and economic activ- ity in parts of the Democratic Republic of the Congo

Aberrant Notch1-dependent effects on glomerular parietal epithelial cells promotes collapsing focal segmental glomerulosclerosis with progressive podocyte loss.

PubMed

Ueno, Toshiharu; Kobayashi, Namiko; Nakayama, Makiko; Takashima, Yasutoshi; Ohse, Takamoto; Pastan, Ira; Pippin, Jeffrey W; Shankland, Stuart J; Uesugi, Noriko; Matsusaka, Taiji; Nagata, Michio

2013-06-01

Collapsing focal segmental glomerulosclerosis (cFSGS) is a progressive kidney disease characterized by glomerular collapse with epithelial hyperplasia. Here we used a transgenic mouse model of cFSGS with immunotoxin-induced podocyte-specific injury to determine the role for Notch signaling in its pathogenesis. The mice exhibited progressive loss of podocytes and severe proteinuria concomitant with histological features of cFSGS. Hyperplastic epithelium was negative for genetic podocyte tags, but positive for the parietal epithelial cell marker claudin-1, and expressed Notch1, Jagged1, and Hes1 mRNA and protein. Enhanced Notch mRNA expression induced by transforming growth factor-β1 in cultured parietal epithelial cells was associated with mesenchymal markers (α-smooth muscle actin, vimentin, and Snail1). Notch inhibition in vitro suppressed these phenotypic transcripts and Notch-dependent cell migration. Moreover, Notch inhibition in vivo significantly decreased parietal epithelial cell lesions but worsened proteinuria and histopathology in our cFSGS model. Thus, aberrant Notch1-mediated parietal epithelial cell migration with phenotypic changes appears to underlie the pathogenesis of cFSGS. Parietal epithelial cell hyperplasia may also represent an adaptive response to compensate for a disrupted filtration barrier with progressive podocyte loss.

The habitat disruption induces immune-suppression and oxidative stress in honey bees

PubMed Central

Morimoto, Tomomi; Kojima, Yuriko; Toki, Taku; Komeda, Yayoi; Yoshiyama, Mikio; Kimura, Kiyoshi; Nirasawa, Keijiro; Kadowaki, Tatsuhiko

2011-01-01

The honey bee is a major insect used for pollination of many commercial crops worldwide. Although the use of honey bees for pollination can disrupt the habitat, the effects on their physiology have never been determined. Recently, honey bee colonies have often collapsed when introduced in greenhouses for pollination in Japan. Thus, suppressing colony collapses and maintaining the number of worker bees in the colonies is essential for successful long-term pollination in greenhouses and recycling of honey bee colonies. To understand the physiological states of honey bees used for long-term pollination in greenhouses, we characterized their gene expression profiles by microarray. We found that the greenhouse environment changes the gene expression profiles and induces immune-suppression and oxidative stress in honey bees. In fact, the increase of the number of Nosema microsporidia and protein carbonyl content was observed in honey bees during pollination in greenhouses. Thus, honey bee colonies are likely to collapse during pollination in greenhouses when heavily infested with pathogens. Degradation of honey bee habitat by changing the outside environment of the colony, during pollination services for example, imposes negative impacts on honey bees. Thus, worldwide use of honey bees for crop pollination in general could be one of reasons for the decline of managed honey bee colonies. PMID:22393496

3-D explosions: a meditation on rotation (and magnetic fields)

NASA Astrophysics Data System (ADS)

Wheeler, J. C.

This is the text of an introduction to a workshop on asymmetric explosions held in Austin in June, 2003. The great progress in supernova research over thirty-odd years is briefly reviewed. The context in which the meeting was called is then summarized. The theoretical success of the intrinsically multidimensional delayed detonation paradigm in explaining the nature of Type Ia supernovae coupled with new techniques of observations in the near IR and with spectropolarimetry promise great advances in understanding binary progenitors, the explosion physics, and the ever more accurate application to cosmology. Spectropolarimetry has also revealed the strongly asymmetric nature of core collapse and given valuable perspectives on the supernova - gamma-ray burst connection. The capability of the magneto-rotational instability to rapidly create strong toroidal magnetic fields in the core collapse ambiance is outlined. This physics may be the precursor to driving MHD jets that play a role in asymmetric supernovae. Welcome to the brave new world of three-dimensional explosions!

Detection of hazardous cavities with combined geophysical methods

NASA Astrophysics Data System (ADS)

Hegymegi, Cs.; Nyari, Zs.; Pattantyus-Abraham, M.

2003-04-01

Unknown near-surface cavities often cause problems for municipal communities all over the world. This is the situation in Hungary in many towns and villages, too. Inhabitants and owners of real estates (houses, cottages, lands) are responsible for the safety and stability of their properties. The safety of public sites belongs to the local municipal community. Both (the owner and the community) are interested in preventing accidents. Near-surface cavities (unknown caves or earlier built and forgotten cellars) usually can be easily detected by surface geophysical methods. Traditional and recently developed measuring techniques in seismics, geoelectrics and georadar are suitable for economical investigation of hazardous, potentially collapsing cavities, prior to excavation and reinforcement. This poster will show some example for detection of cellars and caves being dangerous for civil population because of possible collapse under public sites (road, yard, playground, agricultural territory, etc.). The applied and presented methods are ground penetrating radar, seismic surface tomography and analysis of single traces, geoelectric 2D and 3D resistivity profiling. Technology and processing procedure will be presented.

Area collapse algorithm computing new curve of 2D geometric objects

NASA Astrophysics Data System (ADS)

Buczek, Michał Mateusz

2017-06-01

The processing of cartographic data demands human involvement. Up-to-date algorithms try to automate a part of this process. The goal is to obtain a digital model, or additional information about shape and topology of input geometric objects. A topological skeleton is one of the most important tools in the branch of science called shape analysis. It represents topological and geometrical characteristics of input data. Its plot depends on using algorithms such as medial axis, skeletonization, erosion, thinning, area collapse and many others. Area collapse, also known as dimension change, replaces input data with lower-dimensional geometric objects like, for example, a polygon with a polygonal chain, a line segment with a point. The goal of this paper is to introduce a new algorithm for the automatic calculation of polygonal chains representing a 2D polygon. The output is entirely contained within the area of the input polygon, and it has a linear plot without branches. The computational process is automatic and repeatable. The requirements of input data are discussed. The author analyzes results based on the method of computing ends of output polygonal chains. Additional methods to improve results are explored. The algorithm was tested on real-world cartographic data received from BDOT/GESUT databases, and on point clouds from laser scanning. An implementation for computing hatching of embankment is described.

Space Inside a Liquid Sphere Transforms into De Sitter Space by Hilbert Radius

NASA Astrophysics Data System (ADS)

Rabounski, Dmitri; Borissova, Larissa

2010-04-01

Consider space inside a sphere of incompressible liquid, and space surrounding a mass-point. Metrics of the spaces were deduced in 1916 by Karl Schwarzschild. 1) Our calculation shows that a liquid sphere can be in the state of gravitational collapse (g00 = 0) only if its mass and radius are close to those of the Universe (M = 8.7x10^55 g, a = 1.3x10^28 cm). However if the same mass is presented as a mass-point, the radius of collapse rg (Hilbert radius) is many orders lesser: g00 = 0 realizes in a mass-point's space by other conditions. 2) We considered a liquid sphere whose radius meets, formally, the Hilbert radius of a mass-point bearing the same mass: a = rg, however the liquid sphere is not a collapser (see above). We show that in this case the metric of the liquid sphere's internal space can be represented as de Sitter's space metric, wherein λ = 3/a^2 > 0: physical vacuum (due to the λ-term) is the same as the field of an ideal liquid where ρ0 < 0 and p = -ρ0 c^2 > 0 (the mirror world liquid). The gravitational redshift inside the sphere is produced by the non-Newtonian force of repulsion (which is due to the λ-term, λ = 3/a^2 > 0); it is also calculated.

Using eDNA to detect the distribution and density of invasive crayfish in the Honghe-Hani rice terrace World Heritage site

PubMed Central

Yang, Chunyan; Wang, Lin; Wang, Wenzhi; Zhao, Guigang; Geng, Yupeng; Yu, Douglas W.

2017-01-01

The Honghe-Hani landscape in China is a UNESCO World Natural Heritage site due to the beauty of its thousands of rice terraces, but these structures are in danger from the invasive crayfish Procambarus clarkii. Crayfish dig nest holes, which collapse terrace walls and destroy rice production. Under the current control strategy, farmers self-report crayfish and are issued pesticide, but this strategy is not expected to eradicate the crayfish nor to prevent their spread since farmers are not able to detect small numbers of crayfish. Thus, we tested whether environmental DNA (eDNA) from paddy-water samples could provide a sensitive detection method. In an aquarium experiment, Real-time Quantitative polymerase chain reaction (qPCR) successfully detected crayfish, even at a simulated density of one crayfish per average-sized paddy (with one false negative). In a field test, we tested eDNA and bottle traps against direct counts of crayfish. eDNA successfully detected crayfish in all 25 paddies where crayfish were observed and in none of the 7 paddies where crayfish were absent. Bottle-trapping was successful in only 68% of the crayfish-present paddies. eDNA concentrations also correlated positively with crayfish counts. In sum, these results suggest that single samples of eDNA are able to detect small crayfish populations, but not perfectly. Thus, we conclude that a program of repeated eDNA sampling is now feasible and likely reliable for measuring crayfish geographic range and for detecting new invasion fronts in the Honghe Hani landscape, which would inform regional control efforts and help to prevent the further spread of this invasive crayfish. PMID:28505200

Using eDNA to detect the distribution and density of invasive crayfish in the Honghe-Hani rice terrace World Heritage site.

PubMed

Cai, Wang; Ma, Zhuxin; Yang, Chunyan; Wang, Lin; Wang, Wenzhi; Zhao, Guigang; Geng, Yupeng; Yu, Douglas W

2017-01-01

The Honghe-Hani landscape in China is a UNESCO World Natural Heritage site due to the beauty of its thousands of rice terraces, but these structures are in danger from the invasive crayfish Procambarus clarkii. Crayfish dig nest holes, which collapse terrace walls and destroy rice production. Under the current control strategy, farmers self-report crayfish and are issued pesticide, but this strategy is not expected to eradicate the crayfish nor to prevent their spread since farmers are not able to detect small numbers of crayfish. Thus, we tested whether environmental DNA (eDNA) from paddy-water samples could provide a sensitive detection method. In an aquarium experiment, Real-time Quantitative polymerase chain reaction (qPCR) successfully detected crayfish, even at a simulated density of one crayfish per average-sized paddy (with one false negative). In a field test, we tested eDNA and bottle traps against direct counts of crayfish. eDNA successfully detected crayfish in all 25 paddies where crayfish were observed and in none of the 7 paddies where crayfish were absent. Bottle-trapping was successful in only 68% of the crayfish-present paddies. eDNA concentrations also correlated positively with crayfish counts. In sum, these results suggest that single samples of eDNA are able to detect small crayfish populations, but not perfectly. Thus, we conclude that a program of repeated eDNA sampling is now feasible and likely reliable for measuring crayfish geographic range and for detecting new invasion fronts in the Honghe Hani landscape, which would inform regional control efforts and help to prevent the further spread of this invasive crayfish.

Pyroclastic density currents at Etna volcano, Italy: The 11 February 2014 case study

NASA Astrophysics Data System (ADS)

Andronico, Daniele; Di Roberto, Alessio; De Beni, Emanuela; Behncke, Boris; Bertagnini, Antonella; Del Carlo, Paola; Pompilio, Massimo

2018-05-01

On 11 February 2014, a considerable volume (0.82 to 1.29 × 106 m3) of unstable and hot rocks detached from the lower-eastern flank of the New Southeast Crater (NSEC) at Mt. Etna, producing a pyroclastic density current (PDC). This event was by far the most extensive ever recorded at Mt. Etna since 1999 and has attracted the attention of the scientific community and civil protection to this type of volcanic phenomena, usually occurring without any clear volcanological precursor and especially toward the mechanisms which led to the crater collapse, the PDC flow dynamics and the related volcanic hazard. We present here the results of the investigation carried out on the 11 February 2014 collapse and PDC events; data were obtained through a multidisciplinary approach which includes the analysis of photograph, images from visible and thermal surveillance cameras, and the detailed stratigraphic, textural and petrographic investigations of the PDC deposits. Results suggest that the collapse and consequent PDC was the result of a progressive thermal and mechanical weakening of the cone by repeated surges of magma passing through it during the eruptive activity prior to the 11 February 2014 events, as well as pervasive heating and corrosion by volcanic gas. The collapse of the lower portion of the NSEC was followed by the formation of a relatively hot (up to 750 °C) dense flow which travelled about 2.3 km from the source, stopping shortly after the break of the slope and emplacing the main body of the deposit which ranges between 0.39 and 0.92 × 106 m3. This flow was accompanied a relatively hot cloud of fine ash that dispersed over a wider area. The results presented may contribute to the understanding of this very complex type of volcanic phenomena at Mt. Etna and in similar volcanic settings of the world. In addition, results will lay the basis for the modeling of crater collapse and relative PDC events and consequently for the planning of hazard assessment strategies aimed at reducing the potential risks to scientists and tens of thousands of tourists visiting Etna's summit areas every year.

Combined Effect of Ocean Acidification and Seawater Freshening: Response of Pteropod Swimming Behavior

NASA Astrophysics Data System (ADS)

Manno, C.; Morata, N.; Primicerio, R.

2012-12-01

Increasing anthropogenic carbon dioxide emissions induce ocean acidification. Pteropods, the main planktonic producers of aragonite in the worlds' oceans, may be particularly vulnerable to changes in sea water chemistry. The negative effects are expected to be most severe at high-latitudes, where natural carbonate ion concentrations are low. In this study we investigated the combined effects of ocean acidification and freshening on Limacina retroversa, the dominant pteropod in sub polar areas. Living Limacina retroversa, collected in Northern Norwegian Sea, were exposed to four different pH values ranging from the pre-industrial level to the forecasted end of century ocean acidification scenario. Since over the past half-century the Norwegian Sea has experienced a progressive freshening with time, each pH level was combined with a salinity gradient. Survival, shell degradation and swimming behavior were investigated. Mortality was strongly affected only when both pH and salinity reduced simultaneously. The combined effects of lower salinity and lower pH also affected negatively the ability of pteropods to swim where they decreasing the locomotory speed upwards and increasing the wing beats. Results suggest that, the extra energy cost due to maintaining of body fluids and to avoid sinking (in low salinity scenario) combined with the extra energy cost necessary to counteract the dissolution (in high pCO2 scenario), exceeds the available energy budget of this organism and then pteropods change in swimming behavior and begin to collapse. Since Limacina retroversa play an important role in the transport of carbonates to the deep oceans these findings have significant implications for the mechanisms influencing the inorganic carbon cycle in the sub-polar area.

Predictors of specialist avifaunal decline in coastal marshes.

PubMed

Correll, Maureen D; Wiest, Whitney A; Hodgman, Thomas P; Shriver, W Gregory; Elphick, Chris S; McGill, Brian J; O'Brien, Kathleen M; Olsen, Brian J

2017-02-01

Coastal marshes are one of the world's most productive ecosystems. Consequently, they have been heavily used by humans for centuries, resulting in ecosystem loss. Direct human modifications such as road crossings and ditches and climatic stressors such as sea-level rise and extreme storm events have the potential to further degrade the quantity and quality of marsh along coastlines. We used an 18-year marsh-bird database to generate population trends for 5 avian species (Rallus crepitans, Tringa semipalmata semipalmata, Ammodramus nelsonii subvirgatus, Ammodramus caudacutus, and Ammodramus maritimus) that breed almost exclusively in tidal marshes, and are potentially vulnerable to marsh degradation and loss as a result of anthropogenic change. We generated community and species trends across 3 spatial scales and explored possible drivers of the changes we observed, including marsh ditching, tidal restriction through road crossings, local rates of sea-level rise, and potential for extreme flooding events. The specialist community showed negative trends in tidally restricted marshes (-2.4% annually from 1998 to 2012) but was stable in unrestricted marshes across the same period. At the species level, we found negative population trends in 3 of the 5 specialist species, ranging from -4.2% to 9.0% annually. We suggest that tidal restriction may accelerate degradation of tidal marsh resilience to sea-level rise by limiting sediment supply necessary for marsh accretion, resulting in specialist habitat loss in tidally restricted marshes. Based on our findings, we predict a collapse of the global population of Saltmarsh Sparrows (A. caudacutus) within the next 50 years and suggest that immediate conservation action is needed to prevent extinction of this species. We also suggest mitigation actions to restore sediment supply to coastal marshes to help sustain this ecosystem into the future. © 2016 Society for Conservation Biology.

Inorganic chemical composition and chemical reactivity of settled dust generated by the World Trade Center building collapse: Chapter 12

USGS Publications Warehouse

Plumlee, Geoffrey S.; Hageman, Philip L.; Lamothe, Paul J.; Ziegler, Thomas L.; Meeker, Gregory P.; Theodorakos, Peter M.; Brownfield, Isabelle; Adams, Monique G.; Swayze, Gregg A.; Hoefen, Todd M.; Taggart, Joseph E.; Clark, Roger N.; Wilson, S.; Sutley, Stephen J.

2009-01-01

Samples of dust deposited around lower Manhattan by the September 11, 2001, World Trade Center (WTC) collapse have inorganic chemical compositions that result in part from the variable chemical contributions of concrete, gypsum wallboard, glass fibers, window glass, and other materials contained in the buildings. The dust deposits were also modified chemically by variable interactions with rain water or water used in street washing and fire fighting. Chemical leach tests using deionized water as the extraction fluid show the dust samples can be quite alkaline, due primarily to reactions with calcium hydroxide in concrete particles. Calcium and sulfate are the most soluble components in the dust, but many other elements are also readily leached, including metals such as Al, Sb, Mo Cr, Cu, and Zn. Indoor dust samples produce leachates with higher pH, alkalinity, and dissolved solids than outdoor dust samples, suggesting most outdoor dust had reacted with water and atmospheric carbon dioxide prior to sample collection. Leach tests using simulated lung fluids as the extracting fluid suggest that the dust might also be quite reactive in fluids lining the respiratory tract, resulting in dissolution of some particles and possible precipitation of new phases such as phosphates, carbonates, and silicates. Results of these chemical characterization studies can be used by health scientists as they continue to track and interpret health effects resulting from the short-term exposure to the initial dust cloud and the longer-term exposure to dusts resuspended during cleanup.

Comparisons of the dust/smoke particulate that settled inside the surrounding buildings and outside on the streets of southern New York City after the collapse of the World Trade Center, September 11, 2001.

PubMed

Yiin, Lih-Ming; Millette, James R; Vette, Alan; Ilacqua, Vito; Quan, Chunli; Gorczynski, John; Kendall, Michaela; Chen, Lung Chi; Weisel, Clifford P; Buckley, Brian; Yang, Ill; Lioy, Paul J

2004-05-01

The collapse of the World Trade Center (WTC) on September 11, 2001, generated large amounts of dust and smoke that settled in the surrounding indoor and outdoor environments in southern Manhattan. Sixteen dust samples were collected from undisturbed locations inside two uncleaned buildings that were adjacent to Ground Zero. These samples were analyzed for morphology, metals, and organic compounds, and the results were compared with the previously reported outdoor WTC dust/smoke results. We also analyzed seven additional dust samples provided by residents in the local neighborhoods. The morphologic analyses showed that the indoor WTC dust/smoke samples were similar to the outdoor WTC dust/smoke samples in composition and characteristics but with more than 50% mass in the <53-microm size fraction. This was in contrast to the outdoor samples that contained >50% of mass above >53 microm. Elemental analyses also showed the similarities, but at lower concentrations. Organic compounds present in the outdoor samples were also detected in the indoor samples. Conversely, the resident-provided convenience dust samples were different from either the WTC indoor or outdoor samples in composition and pH, indicating that they were not WTC-affected locations. In summary, the indoor dust/smoke was similar in concentration to the outdoor dust/smoke but had a greater percentage of mass <53 microm in diameter.

Subsurface architecture of a strike-slip collapse structure: insights from Ilopango caldera, El Salvador

NASA Astrophysics Data System (ADS)

Saxby, Jennifer; Gottsmann, Joachim; Cashman, Katherine; Gutierrez, Eduardo

2016-04-01

While most calderas are created by roof collapse along ring-like faults into an emptying magma reservoir during a large and violent explosive eruption, an additional condition for caldera formation may be tectonically induced extensional stresses. Here we provide geophysical insights into the shallow sub-volcanic plumbing system of a collapse caldera in a major strike-slip tectonic setting by inverting Bouguer gravity data from the Ilopango caldera in El Salvador. Despite a long history of catastrophic eruptions with the most recent in 500 A.D., the internal architecture of the caldera has not been investigated, although studies of the most recent eruption have not identified the ring faults commonly associated with caldera collapse. The gravity data show that low-density material aligned along the principal stress orientations of the El Salvador Fault Zone (ESFZ) forms a pronounced gravity low beneath the caldera. Extending to around 6 km depth, the low density structure likely maps a complex stacked shallow plumbing system composed of magmatic and fractured hydrothermal reservoirs. A substantial volume of the plumbing system must be composed of a vapour phase to explain the modeled negative density contrasts. We use these constraints to map the possible multi-phase parameter space contributing to the subsurface architecture of the caldera and propose that the local extension along the complex ESFZ controls accumulation, ascent and eruption of magma at Ilopango. The data further suggest that future eruptions at Ilopango could be facilitated by rapid rise of magma along conjugate fault damage zones through a mechanically weak crust under tension. This may explain the absence of clear ring fault structures at the caldera.

Cardiorespiratory collapse at high temperature in swimming adult sockeye salmon

PubMed Central

Eliason, Erika J.; Clark, Timothy D.; Hinch, Scott G.; Farrell, Anthony P.

2013-01-01

Elevated summer river temperatures are associated with high in-river mortality in adult sockeye salmon (Oncorhynchus nerka) during their once-in-a-lifetime spawning migration up the Fraser River (British Columbia, Canada). However, the mechanisms underlying the decrease in whole-animal performance and cardiorespiratory collapse above optimal temperatures for aerobic scope (Topt) remain elusive for aquatic ectotherms. This is in part because all the relevant cardiorespiratory variables have rarely been measured directly and simultaneously during exercise at supra-optimal temperatures. Using the oxygen- and capacity-limited thermal tolerance hypothesis as a framework, this study simultaneously and directly measured oxygen consumption rate (MO2), cardiac output , heart rate (fH), and cardiac stroke volume (Vs), as well as arterial and venous blood oxygen status in adult sockeye salmon swimming at temperatures that bracketed Topt to elucidate possible limitations in oxygen uptake into the blood or internal delivery through the oxygen cascade. Above Topt, the decline in MO2max and aerobic scope was best explained by a cardiac limitation, triggered by reduced scope for fH. The highest test temperatures were characterized by a negative scope for fH, dramatic decreases in maximal and maximal Vs, and cardiac dysrhythmias. In contrast, arterial blood oxygen content and partial pressure were almost insensitive to supra-optimal temperature, suggesting that oxygen delivery to and uptake by the gill were not a limiting factor. We propose that the high-temperature-induced en route mortality in migrating sockeye salmon may be at least partly attributed to physiological limitations in aerobic performance due to cardiac collapse via insufficient scope for fH. Furthermore, this improved mechanistic understanding of cardiorespiratory collapse at high temperature is likely to have broader application to other salmonids and perhaps other aquatic ectotherms. PMID:27293592

Cardiorespiratory collapse at high temperature in swimming adult sockeye salmon.

PubMed

Eliason, Erika J; Clark, Timothy D; Hinch, Scott G; Farrell, Anthony P

2013-01-01

Elevated summer river temperatures are associated with high in-river mortality in adult sockeye salmon (Oncorhynchus nerka) during their once-in-a-lifetime spawning migration up the Fraser River (British Columbia, Canada). However, the mechanisms underlying the decrease in whole-animal performance and cardiorespiratory collapse above optimal temperatures for aerobic scope (T opt) remain elusive for aquatic ectotherms. This is in part because all the relevant cardiorespiratory variables have rarely been measured directly and simultaneously during exercise at supra-optimal temperatures. Using the oxygen- and capacity-limited thermal tolerance hypothesis as a framework, this study simultaneously and directly measured oxygen consumption rate (MO2), cardiac output [Formula: see text], heart rate (f H), and cardiac stroke volume (V s), as well as arterial and venous blood oxygen status in adult sockeye salmon swimming at temperatures that bracketed T opt to elucidate possible limitations in oxygen uptake into the blood or internal delivery through the oxygen cascade. Above T opt, the decline in MO2max and aerobic scope was best explained by a cardiac limitation, triggered by reduced scope for f H. The highest test temperatures were characterized by a negative scope for f H, dramatic decreases in maximal [Formula: see text] and maximal V s, and cardiac dysrhythmias. In contrast, arterial blood oxygen content and partial pressure were almost insensitive to supra-optimal temperature, suggesting that oxygen delivery to and uptake by the gill were not a limiting factor. We propose that the high-temperature-induced en route mortality in migrating sockeye salmon may be at least partly attributed to physiological limitations in aerobic performance due to cardiac collapse via insufficient scope for f H. Furthermore, this improved mechanistic understanding of cardiorespiratory collapse at high temperature is likely to have broader application to other salmonids and perhaps other aquatic ectotherms.

Soil Atterberg limits of different weathering profiles of the collapsing gullies in the hilly granitic region of southern China

NASA Astrophysics Data System (ADS)

Deng, Yusong; Cai, Chongfa; Xia, Dong; Ding, Shuwen; Chen, Jiazhou; Wang, Tianwei

2017-04-01

Collapsing gullies are one of the most serious soil erosion problems in the tropical and subtropical areas of southern China. However, few studies have been performed on the relationship of soil Atterberg limits with soil profiles of the collapsing gullies. Soil Atterberg limits, which include plastic limit and liquid limit, have been proposed as indicators for soil vulnerability to degradation. Here, the soil Atterberg limits within different weathering profiles and their relationships with soil physicochemical properties were investigated by characterizing four collapsing gullies in four counties in the hilly granitic region of southern China. The results showed that with the fall of weathering degree, there was a sharp decrease in plastic limit, liquid limit, plasticity index, soil organic matter, cation exchange capacity and free iron oxide. Additionally, there was a gradual increase in liquidity index, a sharp increase in particle density and bulk density followed by a slight decline, a decrease in the finer soil particles, a noticeable decline in the clay contents, and a considerable increase in the gravel and sand contents. The plastic limit varied from 19.43 to 35.93 % in TC, 19.51 to 33.82 % in GX, 19.32 to 35.58 % in AX and 18.91 to 36.56 % in WH, while the liquid limit varied from 30.91 to 62.68 % in TC, 30.89 to 57.70 % in GX, 32.48 to 65.71 % in AX and 30.77 to 62.70 % in WH, respectively. The soil Atterberg limits in the sandy soil layers and detritus layers were lower than those in the surface layers and red soil layers, which results in higher vulnerability of the sandy soil layers and detritus layers to erosion and finally the formation of the collapsing gully. The regression analyses showed that soil Atterberg limits had significant and positive correlation with SOM, clay content, cationic exchange capacity and Fed, significant and negative correlation with sand content and no obvious correlation with other properties. The results of this study revealed that soil Atterberg limits are an informative indicator to reflect the weathering degree of different weathering profiles of the collapsing gullies in the hilly granitic region.

Parents' job insecurity affects children's grade performance through the indirect effects of beliefs in an unjust world and negative mood.

PubMed

Barling, J; Mendelson, M B

1999-10-01

The authors postulated a model in which children's perceptions of their parents' job insecurity indirectly affect their grade performance through the effects of beliefs in an unjust world and negative mood. A total of 127 undergraduate students (55 male, 72 female) completed questionnaires on their perceptions of their parents' job insecurity and their own beliefs in an unjust world and negative mood. The parents reported on their own job insecurity. In addition, students provided their course grades from the previous semester 3 months after completing the questionnaires. Support for the proposed model was provided using LISREL 8.

Threats, rewards, and attention deployment in anxious youth and adults: An eye tracking study.

PubMed

Shechner, Tomer; Jarcho, Johanna M; Wong, Stuart; Leibenluft, Ellen; Pine, Daniel S; Nelson, Eric E

2017-01-01

The current study examines anxiety and age associations with attention allocation and physiological response to threats and rewards. Twenty-two healthy-adults, 20 anxious-adults, 26 healthy-youth, and 19 anxious-youth completed two eye-tracking tasks. In the Visual Scene Task (VST), participants' fixations were recorded while they viewed a central neutral image flanked by two threatening or two rewarding stimuli. In the Negative Words Task (NWT), physiological response was measured by means of pupil diameter change while negative and neutral words were presented. For both tasks, no interaction was found between anxiety and age-group. In the VST, anxious participants avoided the threatening images when groups were collapsed across age. Similarly, adults but not adolescents avoided the threatening images when collapsed across anxiety. No differences were found for rewarding images. In NWT, all subjects demonstrated increase in pupil dilation after word presentation. Only main effect of age emerged with stronger pupil dilation in adults than children. Finally, maximum pupil change was correlated with threat avoidance bias in the scene task. Gaze patterns and pupil dilation show that anxiety and age are associated with attention allocation to threats. The relations between attention and autonomic arousal point to a complex interaction between bottom-up and top-down processes as they relate to attention allocation. Copyright © 2015 Elsevier B.V. All rights reserved.

Similarity to the Self Affects Memory for Impressions of Others in Younger and Older Adults

PubMed Central

Park, Jung M.; Gutchess, Angela H.

2015-01-01

Objectives. Similarity to the self has been shown to affect memory for impressions in younger adults, suggesting a self-reference effect in person memory. Because older adults show comparable self-reference effects, but prioritize memory for positive over negative information relative to young adults, we examined age differences in self-similarity effects on memory for positive and negative impressions. Method. Younger and older adults formed positive and negative impressions of others differing in the degree of similarity to the self (high, medium, low). Results. For positive impressions, both groups showed enhanced memory for self-similar others relative to dissimilar others, whereas for negative impressions, memory was poorer for those similar to the self. When collapsed across similarity to the self, younger adults remembered negative impressions better than older adults, but interestingly, older adults exhibited a trend for better memory for the positive impressions. Discussion. Results suggest that self-reference effects in impression memory are preserved with age and that older adults exhibit positivity effects in person memory consistent with previous findings. PMID:24389124

Surface tension and negative pressure interior of a non-singular ‘black hole’

NASA Astrophysics Data System (ADS)

Mazur, Pawel O.; Mottola, Emil

2015-11-01

The constant density interior Schwarzschild solution for a static, spherically symmetric collapsed star has a divergent pressure when its radius R≤slant \\frac{9}{8}{R}s=\\frac{9}{4}{GM}. We show that this divergence is integrable, and induces a non-isotropic transverse stress with a finite redshifted surface tension on a spherical surface of radius {R}0=3R\\sqrt{1-\\frac{8}{9}\\frac{R }{{R}s}}. For r\\lt {R}0 the interior Schwarzschild solution exhibits negative pressure. When R={R}s, the surface is localized at the Schwarzschild radius itself, {R}0={R}s, and the solution has constant negative pressure p=-\\bar{ρ } everywhere in the interior r\\lt {R}s, thereby describing a gravitational condensate star, a fully collapsed non-singular state already inherent in and predicted by classical general relativity. The redshifted surface tension of the condensate star surface is given by {τ }s={{Δ }}κ /8π G, where {{Δ }}κ ={κ }+-{κ }-=2{κ }+=1/{R}s is the difference of equal and opposite surface gravities between the exterior and interior Schwarzschild solutions. The First Law, {{d}}M={{d}}{E}V+{τ }s {{d}}A is recognized as a purely mechanical classical relation at zero temperature and zero entropy, describing the volume energy and surface energy change respectively. The Schwarzschild time t of such a non-singular gravitational condensate star is a global time, fully consistent with unitary time evolution in quantum theory. A clear observational test of gravitational condensate stars with a physical surface versus black holes is the discrete surface modes of oscillation which should be detectable by their gravitational wave signatures.

Prediction of the wetting-induced collapse behaviour using the soil-water characteristic curve

NASA Astrophysics Data System (ADS)

Xie, Wan-Li; Li, Ping; Vanapalli, Sai K.; Wang, Jia-Ding

2018-01-01

Collapsible soils go through three distinct phases in response to matric suction decrease during wetting: pre-collapse phase, collapse phase and post-collapse phase. It is reasonable and conservative to consider a strain path that includes a pre-collapse phase in which constant volume is maintained and a collapse phase that extends to the final matric suction to be experienced by collapsible soils during wetting. Upon this assumption, a method is proposed for predicting the collapse behaviour due to wetting. To use the proposed method, two parameters, critical suction and collapse rate, are required. The former is the suction value below which significant collapse deformations take place in response to matric suction decease, and the later is the rate at which void ratio reduces with matric suction in the collapse phase. The value of critical suction can be estimated from the water-entry value taking account of both the microstructure characteristics and collapse mechanism of fine-grained collapsible soils; the wetting soil-water characteristic curve thus can be used as a tool. Five sets of data of wetting tests on both compacted and natural collapsible soils reported in the literature were used to validate the proposed method. The critical suction values were estimated from the water-entry value with parameter a that is suggested to vary between 0.10 and 0.25 for compacted soils and to be lower for natural collapsible soils. The results of a field permeation test in collapsible loess soils were also used to validate the proposed method. The relatively good agreement between the measured and estimated collapse deformations suggests that the proposed method can provide reasonable prediction of the collapse behaviour due to wetting.

Entanglement entropy production in gravitational collapse: covariant regularization and solvable models

NASA Astrophysics Data System (ADS)

Bianchi, Eugenio; De Lorenzo, Tommaso; Smerlak, Matteo

2015-06-01

We study the dynamics of vacuum entanglement in the process of gravitational collapse and subsequent black hole evaporation. In the first part of the paper, we introduce a covariant regularization of entanglement entropy tailored to curved spacetimes; this regularization allows us to propose precise definitions for the concepts of black hole "exterior entropy" and "radiation entropy." For a Vaidya model of collapse we find results consistent with the standard thermodynamic properties of Hawking radiation. In the second part of the paper, we compute the vacuum entanglement entropy of various spherically-symmetric spacetimes of interest, including the nonsingular black hole model of Bardeen, Hayward, Frolov and Rovelli-Vidotto and the "black hole fireworks" model of Haggard-Rovelli. We discuss specifically the role of event and trapping horizons in connection with the behavior of the radiation entropy at future null infinity. We observe in particular that ( i) in the presence of an event horizon the radiation entropy diverges at the end of the evaporation process, ( ii) in models of nonsingular evaporation (with a trapped region but no event horizon) the generalized second law holds only at early times and is violated in the "purifying" phase, ( iii) at late times the radiation entropy can become negative (i.e. the radiation can be less correlated than the vacuum) before going back to zero leading to an up-down-up behavior for the Page curve of a unitarily evaporating black hole.

An organic record of terrestrial ecosystem collapse and recovery at the Triassic-Jurassic boundary in East Greenland

NASA Astrophysics Data System (ADS)

Williford, Kenneth H.; Grice, Kliti; Holman, Alexander; McElwain, Jennifer C.

2014-02-01

Terrestrial ecosystem collapse at the end of the Triassic Period coincided with a major mass extinction in the marine realm and has been linked to increasing atmospheric carbon dioxide, global warming, and fire activity. Extractable hydrocarbons in samples from the fluvial Triassic-Jurassic boundary section at Astartekløft, East Greenland were analyzed to investigate the molecular and isotopic organic record of biotic and environmental change during this event. Carbon isotopic compositions of individual plant wax lipids show a >4‰ negative excursion coinciding with peak extinction and a further decrease of 2‰ coinciding with peak pCO2 as estimated from the stomatal indices of fossil Gingkoales. An increase of ˜30‰ in the hydrogen isotopic compositions of the same plant wax lipids coincides with ecosystem collapse, suggesting that the biotic crisis was accompanied by strong hydrologic change. Concentrations of polycyclic aromatic hydrocarbons related to combustion also increase together with abrupt plant diversity loss and peak with fossil charcoal abundance and maximum plant turnover, supporting the role of fire in terrestrial extinctions. Anomalously high concentrations of a monoaromatic diterpenoid related to gymnosperm resin derivatives (and similar to dehydroabietane) occur uniquely in samples from the boundary bed, indicating that environmental stress factors leading to peak plant extinction stimulated increased resin production, and that plant resin derivatives may be effective biomarkers of terrestrial ecosystem stress.

KSC-2012-4918

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – A new 9/11 memorial was dedicated in front of Fire Station 1 at NASA’s Kennedy Space Center in Florida. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

Entrepreneurial proliferation: Russia`s nuclear industry suits the buyers market. Master`s thesis

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

Whalen, T.D.; Williams, A.R.

1995-06-01

The Soviet Union collapsed in December 1991, bringing an end to four decades of the Cold War. A system of tight centralized controls has given way to chaotic freedom and un-managed, entrepreneurial capitalism. Of immediate concern to most world leaders has been the control and safety of over 30,000 Soviet nuclear weapons. After 1991, the Soviet, centralized system of management lost one key structural element: a reliable `human factor` for nuclear material control. The Soviet systems for physical security and material control are still in place in the nuclear inheritor states - Russia, Ukraine, Khazakhnstan, and Belarus - but theymore » do not restrain or regulate their nuclear industry. In the chaos created by the Soviet collapse, the nonproliferation regime may not adequately temper the supply of the nuclear materials of the new inheritor states. This could permit organizations or states seeking nuclear weapons easier access to fissile materials. New initiatives such as the United States Cooperative Threat Reduction program, which draws upon U.S. technology and expertise to help the NIS solve these complex problems, are short-tern tactics. At present there are no strategies which address the long-tern root problems caused by the Soviet collapse.This thesis demonstrates the extent of the nuclear control problems in Russia. Specifically, we examine physical security, material control and accounting regulation and enforcement, and criminal actions. It reveals that the current lack of internal controls make access to nuclear materials easier for aspiring nuclear weapons States.« less

Pathogenesis of varroosis at the level of the honey bee (Apis mellifera) colony.

PubMed

Wegener, J; Ruhnke, H; Scheller, K; Mispagel, S; Knollmann, U; Kamp, G; Bienefeld, K

2016-01-01

The parasitic mite Varroa destructor, in interaction with different viruses, is the main cause of honey bee colony mortality in most parts of the world. Here we studied how effects of individual-level parasitization are reflected by the bee colony as a whole. We measured disease progression in an apiary of 24 hives with differing degree of mite infestation, and investigated its relationship to 28 biometrical, physiological and biochemical indicators. In early summer, when the most heavily infested colonies already showed reduced growth, an elevated ratio of brood to bees, as well as a strong presence of phenoloxidase/prophenoloxidase in hive bees were found to be predictors of the time of colony collapse. One month later, the learning performance of worker bees as well as the activity of glucose oxidase measured from head extracts were significantly linked to the timing of colony collapse. Colonies at the brink of collapse were characterized by reduced weight of winter bees and a strong increase in their relative body water content. Our data confirm the importance of the immune system, known from studies of individually-infested bees, for the pathogenesis of varroosis at colony level. However, they also show that single-bee effects cannot always be extrapolated to the colony as a whole. This fact, together with the prominent role of colony-level factors like the ratio between brood and bees for disease progression, stress the importance of the superorganismal dimension of Varroa research. Copyright © 2016 Elsevier Ltd. All rights reserved.

Near-surface, marine seismic-reflection data defines potential hydrogeologic confinement bypass in a tertiary carbonate aquifer, southeastern Florida

USGS Publications Warehouse

Cunningham, Kevin J.; Walker, Cameron; Westcott, Richard L.

2012-01-01

Approximately 210 km of near-surface, high-frequency, marine seismic-reflection data were acquired on the southeastern part of the Florida Platform between 2007 and 2011. Many high-resolution, seismic-reflection profiles, interpretable to a depth of about 730 m, were collected on the shallow-marine shelf of southeastern Florida in water as shallow as 1 m. Landward of the present-day shelf-margin slope, these data image middle Eocene to Pleistocene strata and Paleocene to Pleistocene strata on the Miami Terrace. This high-resolution data set provides an opportunity to evaluate geologic structures that cut across confining units of the Paleocene to Oligocene-age carbonate rocks that form the Floridan aquifer system.Seismic profiles image two structural systems, tectonic faults and karst collapse structures, which breach confining beds in the Floridan aquifer system. Both structural systems may serve as pathways for vertical groundwater flow across relatively low-permeability carbonate strata that separate zones of regionally extensive high-permeability rocks in the Floridan aquifer system. The tectonic faults occur as normal and reverse faults, and collapse-related faults have normal throw. The most common fault occurrence delineated on the reflection profiles is associated with karst collapse structures. These high-frequency seismic data are providing high quality structural analogs to unprecedented depths on the southeastern Florida Platform. The analogs can be used for assessment of confinement of other carbonate aquifers and the sealing potential of deeper carbonate rocks associated with reservoirs around the world.

Interferometrically enhanced sub-terahertz picosecond imaging utilizing a miniature collapsing-field-domain source

NASA Astrophysics Data System (ADS)

Vainshtein, Sergey N.; Duan, Guoyong; Mikhnev, Valeri A.; Zemlyakov, Valery E.; Egorkin, Vladimir I.; Kalyuzhnyy, Nikolay A.; Maleev, Nikolai A.; Näpänkangas, Juha; Sequeiros, Roberto Blanco; Kostamovaara, Juha T.

2018-05-01

Progress in terahertz spectroscopy and imaging is mostly associated with femtosecond laser-driven systems, while solid-state sources, mainly sub-millimetre integrated circuits, are still in an early development phase. As simple and cost-efficient an emitter as a Gunn oscillator could cause a breakthrough in the field, provided its frequency limitations could be overcome. Proposed here is an application of the recently discovered collapsing field domains effect that permits sub-THz oscillations in sub-micron semiconductor layers thanks to nanometer-scale powerfully ionizing domains arising due to negative differential mobility in extreme fields. This shifts the frequency limit by an order of magnitude relative to the conventional Gunn effect. Our first miniature picosecond pulsed sources cover the 100-200 GHz band and promise milliwatts up to ˜500 GHz. Thanks to the method of interferometrically enhanced time-domain imaging proposed here and the low single-shot jitter of ˜1 ps, our simple imaging system provides sufficient time-domain imaging contrast for fresh-tissue terahertz histology.

Pre-Hispanic agricultural decline prior to the Spanish Conquest in southern Central America

NASA Astrophysics Data System (ADS)

Taylor, Zachary P.; Horn, Sally P.; Finkelstein, David B.

2013-08-01

Archeological and paleoenvironmental records from southern Central America attribute population collapse to the Spanish Conquest about 500 years ago. Paleoclimate records from the circum-Caribbean have shown evidence of severe, regional droughts that contributed to the collapse of the Mayan Civilization, but there are few records of these droughts in southern Central America and no records of their effects on prehistoric populations in the region. Here we present a high-resolution lake sediment record of prehistoric agricultural activities using bulk sediment stable carbon isotopes from Laguna Zoncho, Costa Rica. We find isotopic evidence that agriculture was nearly absent from the watershed approximately 220 years prior to the Spanish arrival in Costa Rica and identify two distinct periods of agricultural decline, 1150-970 and 860-640 cal yr BP, which correspond to severe droughts in central Mexico. We attribute decreases in agriculture to a weakened Central American monsoon, which would have shortened the growing season at Laguna Zoncho, reduced crop yields, and negatively affected prehistoric populations.

The effect of a disastrous flood on the quality of life in Dongting lake area in China.

PubMed

Tan, H Z; Luo, Y J; Wen, S W; Liu, A Z; Li, S Q; Yang, T B; Sun, Z Q

2004-01-01

We carried out an epidemiological study to assess the impact of flood on the quality of life (QOL) of residents in the affected areas in China. We used a natural experiment approach, randomly selected 494 adults from 18 villages, which suffered from flooding as a result of embankments collapsing, 473 adults from 16 villages, which suffered from, soaked flood, and 773 adults from 11 villages without flood (control group). We used the Generic QOL Inventory-74 (GQOLI-74), social support scale, and questionnaires to assess the QOL of all study participants. The QOL was significantly poorer in soaked group (58.4) and (especially) in collapsed group (55.1) than in control group (59.5, p<0.001). Adjustment for potential confounding factors did not change the results. The impact of flood on QOL was stronger among farmers, seniors, persons with introvert personality, and residents with adverse life-events, whereas social support and extrovert personalities offset the negative impact of flood on QOL.

A mineralogical and granulometric study of Cayambe volcano debris avalanche deposit

NASA Astrophysics Data System (ADS)

Detienne, M.; Delmelle, P.; Guevara, A.; Samaniego, P.; Bustillos, J.; Sonnet, P.; Opfergelt, S.

2013-12-01

Volcano flank/sector collapse represents one of the most catastrophic volcanic hazards. Various volcanic and non-volcanic processes are known to decrease the stability of a volcanic cone, eventually precipitating its gravitational failure. Among them, hydrothermal alteration of volcanic rocks leading to clay mineral formation is recognized as having a large negative impact on rock strength properties. Furthermore, the presence of hydrothermal clays in the collapsing mass influences the behavior of the associated volcanic debris avalanche. In particular, clay-containing debris avalanches seem to travel farther and spread more widely than avalanches of similar volume but which do not incorporate hydrothermally-altered materials. However, the relationship between hydrothermal alteration, flank collapse and debris avalanche behavior is not well understood. The objective of this study is to better determine the volume and composition of hydrothermal clay minerals in the poorly characterized debris avalanche deposit (DAD) of Cayambe composite volcano, located in a densely populated area ~70 km northeast of Quito, Ecuador. Cayambe DAD originated from a sector collapse, which occurred less than 200 ka ago. The DAD is 10-20 m thick and has an estimated total volume of ~0.85 Km3. The H/L ratio (where H is the vertical drop and L is the travel distance of the avalanche) for Cayambe DAD is ~0.095, suggesting a high mobility. In the medial-distal zone, at 9-20 km from its source, the DAD consists of an unstratified and unsorted matrix supporting millimetric to metric clasts. It has a matrix facies (i.e. rich in particles < 2 mm) enriched in hydrothermally-altered materials. Preliminary results of granulometry measurements indicate that the matrix corresponds to ~55 wt.% of the deposit and suggest that the DAD behaved as a cohesive debris flow. Analysis of 13 matrix samples reveals a large variability in particle size distribution. This may reflect poor mixing of the collapsed material during transport. The clay fraction content in the matrix ranges from 15 to 30 wt.%, and does not show a relationship with the sample position in the DAD. Mineralogical determinations are in progress and will be presented.

Cascade-based attacks on complex networks

NASA Astrophysics Data System (ADS)

Motter, Adilson E.; Lai, Ying-Cheng

2002-12-01

We live in a modern world supported by large, complex networks. Examples range from financial markets to communication and transportation systems. In many realistic situations the flow of physical quantities in the network, as characterized by the loads on nodes, is important. We show that for such networks where loads can redistribute among the nodes, intentional attacks can lead to a cascade of overload failures, which can in turn cause the entire or a substantial part of the network to collapse. This is relevant for real-world networks that possess a highly heterogeneous distribution of loads, such as the Internet and power grids. We demonstrate that the heterogeneity of these networks makes them particularly vulnerable to attacks in that a large-scale cascade may be triggered by disabling a single key node. This brings obvious concerns on the security of such systems.

Testing collapse models by a thermometer

NASA Astrophysics Data System (ADS)

Bahrami, M.

2018-05-01

Collapse models postulate that space is filled with a collapse noise field, inducing quantum Brownian motions, which are dominant during the measurement, thus causing collapse of the wave function. An important manifestation of the collapse noise field, if any, is thermal energy generation, thus disturbing the temperature profile of a system. The experimental investigation of a collapse-driven heating effect has provided, so far, the most promising test of collapse models against standard quantum theory. In this paper, we calculate the collapse-driven heat generation for a three-dimensional multi-atomic Bravais lattice by solving stochastic Heisenberg equations. We perform our calculation for the mass-proportional continuous spontaneous localization collapse model with nonwhite noise. We obtain the temperature distribution of a sphere under stationary-state and insulated surface conditions. However, the exact quantification of the collapse-driven heat-generation effect highly depends on the actual value of cutoff in the collapse noise spectrum.

Evolution of proto-neutron stars with quarks.

PubMed

Pons, J A; Steiner, A W; Prakash, M; Lattimer, J M

2001-06-04

Neutrino fluxes from proto-neutron stars with and without quarks are studied. Observable differences become apparent after 10-20 s of evolution. Sufficiently massive stars containing negatively charged, strongly interacting, particles collapse to black holes during the first minute of evolution. Since the neutrino flux vanishes when a black hole forms, this is the most obvious signal that quarks (or other types of strange matter) have appeared. The metastability time scales for stars with quarks are intermediate between those containing hyperons and kaon condensates.

Turquoise Artifact from Teotihuacan

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

Spence, Michael W.; Harbottle, Garman; Weigand, Phil C.

1999-07-01

Turquoise artifacts appeared sporadically in Mesoamerica as early as the Formative period (Merry de Morales 1987:100, Figure 8.4; Weigand 1989:43). Most occurrences, however, postdate the collapse of Teotihuacan. In the Late Classic and Postclassic periods increasing quantities are found, often in the form of elaborate mosaics, in a wide variety of contexts in central, west and northwest Mexico. Neutron activation analysis has determined that much of this turquoise derives from sources in the southwestern United States (Weigand et al. 1977; Harbottle and Weigand 1992; Weigand and Harbottle 1993). Teotihuacan played a major role in Mesoamerica during the Terminal Formative andmore » Early-Middle Classic periods. It was the dominant power in central Mexico from about the time of Christ to its collapse at about A.D. 650 (Millon 1988, 1992; Cowgill 1996). Throughout this period goods flowed into Teotihuacan from many parts of the Mesoamerican world. Despite this widespread economic interaction, only two pieces of turquoise have been recovered in the city. In the following pages, the context and implications of one of these finds will be examined.« less

Bargaining over an international water resource based on cooperative game theory concepts

NASA Astrophysics Data System (ADS)

Madani, K.; Gholizadeh, S.

2011-12-01

Prior the collapse of the Soviet Union in 1991, Caspian Sea was peacefully shared by Iran and the USSR, based on the two historic treaties between Iran (Persia) and Russia. Collapse of the USSR gave birth to one of the world's serious conflicts over international water resources. Since then, the five littoral states of the Caspian Sea, namely Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan have been negotiating over finding an appropriate allocation scheme for sharing the sea and its valuable energy and environmental resources. Although several solution methods have been proposed, the negotiating parties have been unsuccessful in developing a compromise solution. A range of bargaining solutions are used here to show how cooperative game theory can be used to develop fair and efficient allocation schemes to resolve the Caspian Sea conflict. It is also examined how the negotiators may use their powers to change their shares from the Caspian Sea resources. Finally, the stability of the suggested game theoretic solutions are tested to find the solution which is more acceptable by the negotiating parties.

Evidence for faulting related to dissociation of gas hydrate and release of methane off the southeastern United States

USGS Publications Warehouse

Dillon, William P.; Danforth, W.W.; Hutchinson, D.R.; Drury, R.M.; Taylor, M.H.; Booth, J.S.

1998-01-01

This paper is part of the special publication Gas hydrates: relevance to world margin stability and climatic change (eds J.P. Henriet and J. Mienert). An irregular, faulted, collapse depression about 38 x 18 km in extent is located on the crest of the Blake Ridge offshore from the south- eastern United States. Faults disrupt the sea floor and terminate or sole out about 40-500 m below the sea floor at the base of the gas hydrate stable zone, which is identified from the location of the bottom simulating reflection (BSR). Normal faults are common but reverse faults and folds also are widespread. Folds commonly convert upward into faults. Sediment diapirs and deposits of sediments that were erupted onto the sea floor are also present. Sea-floor depressions at faults may represent locations of liquid/gas vents. The collapse was probably caused by overpressures and by the decoupling of the overlying sediments by gassy muds that existed just beneath the zone of gas hydrate stability.

What Would Have Happened to the Ozone Layer if Chlorofluorocarbons (CFCs) had not been Regulated?

NASA Technical Reports Server (NTRS)

Newman, Paul A.; Oman, L. D.; Douglass, A. R.; Fleming, E. L.; Frith, S. M.; Hurwitz, M. M.; Kawa, S. R.; Jackman, C. H.; Krotkov, N. A.; Nash, E. R.;

Clinical deterioration in pediatric asthmatic patients after September 11, 2001.

PubMed

Szema, Anthony M; Khedkar, Meera; Maloney, Patrick F; Takach, Patricia A; Nickels, Michael S; Patel, Harshit; Modugno, Francesmary; Tso, Alan Y; Lin, Deborah H

2004-03-01

New York City residents were exposed to a variety of inhaled substances after the collapse of the World Trade Center. Exposure to these substances might lead to an increase in asthma severity, with residential distance from Ground Zero predictive of the degree of change. We sought to assess the effect of the World Trade Center collapse on local pediatric asthmatic patients. We retrospectively reviewed the charts of 205 pediatric patients with established asthma from a clinic in lower Manhattan's Chinatown. Clinical data were obtained for the year before and the year after September 11, 2001. Measurements included numbers of visits, asthma medication prescriptions, oral corticosteroid prescriptions, weekly doses of rescue inhaler, and peak expiratory flow rates. Residential zip codes were used to compare the asthma severity of patients living within and beyond a 5-mile radius of Ground Zero. After September 11, 2001, these children had more asthma-related clinic visits (P = .002) and received more prescriptions for asthma medications (P = .018). No significant differences in oral steroid or rescue inhaler use were noted. Those living within 5 miles had more clinic visits after September 11, 2001 (P = .013); the increase in clinic visits for patients living more than 5 miles from Ground Zero was not significant. Mean percent predicted peak expiratory flow rates decreased solely for those patients living within 5 miles of Ground Zero during the 3 months after September 11, 2001. Asthma severity worsened after September 11, 2001, in pediatric asthmatic patients living near Ground Zero. Residential proximity to Ground Zero was predictive of the degree of decrease in asthma health.

Further support for the role of dysfunctional attitudes in models of real-world functioning in schizophrenia.

PubMed

Horan, William P; Rassovsky, Yuri; Kern, Robert S; Lee, Junghee; Wynn, Jonathan K; Green, Michael F

2010-06-01

According to A.T. Beck and colleagues' cognitive formulation of poor functioning in schizophrenia, maladaptive cognitive appraisals play a key role in the expression and persistence of negative symptoms and associated real-world functioning deficits. They provided initial support for this model by showing that dysfunctional attitudes are elevated in schizophrenia and account for significant variance in negative symptoms and subjective quality of life. The current study used structural equation modeling to further evaluate the contribution of dysfunctional attitudes to outcome in schizophrenia. One hundred eleven outpatients and 67 healthy controls completed a Dysfunctional Attitudes Scale, and patients completed a competence measure of functional capacity, clinical ratings of negative symptoms, and interview-based ratings of real-world functioning. Patients reported higher defeatist performance beliefs than controls and these were significantly related to lower functional capacity, higher negative symptoms, and worse community functioning. Consistent with Beck and colleagues' formulation, modeling analyses indicated a significant indirect pathway from functional capacity-->dysfunctional attitudes-->negative symptoms-->real-world functioning. These findings support the value of dysfunctional attitudes for understanding the determinants of outcome in schizophrenia and suggest that therapeutic interventions targeting these attitudes may facilitate functional recovery. (c) 2009 Elsevier Ltd. All rights reserved.

Transport and Microphysics of Aerosols Released by Collapse and Fire of the World Trade Center on September 11, 2001 as Observed by AERONET and MISR

NASA Astrophysics Data System (ADS)

Stenchikov, G. L.; Diner, D.; Kahn, R.; Smirnov, A.; Holben, B.

2005-12-01

Atmospheric pollution has been studied intensively during the last several decades for its impact on climate, visibility, atmospheric chemistry, and public health. Here we consider the aftermath of the catastrophic aerosol release produced by the collapse of the World Trade Center (WTC) in New York City (NYC) on September 11, 2001. The north and south WTC buildings were attacked at 0846 EDT and 0903 EDT, respectively, on September 11, 2001. The collapse of the WTC South Tower at 0959 EDT followed by the crash of the North Tower at 1029 EDT instantaneously pulverized a vast amount of building material, that was reduced to dust and smoke in nearby streets and the atmosphere above. The remains of the WTC complex covered a 16-acre area known as Ground Zero. Intensive combustion continued until September 14, with temperatures occasionally exceeding 1000 C, producing a steady, elevated source of hazardous gases and aerosols. A detailed spatial and temporal description of the pollution fields' evolution is needed to fully understand their environmental and health impact, but many existing in situ aerosol monitoring stations in the vicinity of the WTC were completely plugged with dust immediately after the collapse. However, the aerosol plume was remotely sensed from the ground and from space. Here we combine numerical modeling of micrometeorological fields and pollution transport using the RAMS/HYPACT modeling system with AERONET and MISR retrievals, to realistically reconstruct plume evolution. AERONET collected plume data in NYC from the roof of the Goddard Institute for Space Studies (GISS) in Upper Manhattan. In NYC, aerosol optical depth was rather low until 1800 UTC on September 12; then it increased to ~0.3 (at 440 nm) by 2130 UTC. On September 13, the optical depth was slightly elevated in the morning and increased further beginning at 1700 UTC, reaching ~0.30 by 2000-2200 UTC. The angstrom exponent increased from 1.8 on September 12 to 2.2 in the late afternoon on September 13. MISR viewed the WTC on September 12 at 1603 UTC when the plume blew southwest, reporting the plume altitude to be about 1500 m, and the regionally averaged optical depth to be 0.1 (at 558 nm), with the corresponding angstrom exponent ranging from 1.23 to 1.43. The aerosol retrievals from ground- and space-based instruments provide important constrains for our plume simulations. We were able to calculate relatively accurately the plume height, directionality, and timing. Comparison of calculated and observed column aerosol loading provided by AERONET allowed us to more reliably evaluate the magnitude of the aerosol source on September 12 and 13, 2001.

Depression and embodiment: phenomenological reflections on motility, affectivity, and transcendence.

PubMed

Aho, Kevin A

2013-11-01

This paper integrates personal narratives with the methods of phenomenology in order to draw some general conclusions about 'what it means' and 'what it feels like' to be depressed. The analysis has three parts. First, it explores the ways in which depression disrupts everyday experiences of spatial orientation and motility. This disruption makes it difficult for the person to move and perform basic functional tasks, resulting in a collapse or contraction of the life-world. Second, it illustrates how depression creates a situational atmosphere of emotional indifference that reduces the person's ability to qualitatively distinguish what matters in his or her life because nothing stands out as significant or important anymore. In this regard, depression is distinct from other feelings because it is not directed towards particular objects or situations but to the world as a whole. Finally, the paper examines how depression diminishes the possibility for 'self-creation' or 'self-making'. Restricted by the illness, depression becomes something of a destiny, preventing the person from being open and free to access a range of alternative self-interpretations, identities, and possible ways of being-in-the-world.

Trust, Protocol, Gender, and Power in Interwar British Biomedical Research: Kathleen Chevassut and the “Germ” of Multiple Sclerosis

PubMed Central

Casper, Stephen T.

2011-01-01

In March 1930, reports of the discovery of an organism causative of multiple sclerosis circulated in the British press. At the same time, news of a therapeutically efficacious vaccine also reached the ears of neurologists and patients afflicted with the debilitating degenerative disease. It was soon shown that no organism had been discovered. The events leading up to this ultimately painful episode reveal many of the central problems created when social conventions and a sense of decorum scripted received understanding of good scientific practice rather than actual regulatory frameworks. In the absence of such frameworks, few means were present to censor inappropriate scientific conduct. This story thus provides a window into an emergent world of state-sponsored biomedical research; a world where recrimination, gossip, misogyny, uncertainty, exaggeration, and dreams and delusions of scientific and therapeutic progress were collapsed together. PMID:20478897

Collapse of the world's largest herbivores.

PubMed

Ripple, William J; Newsome, Thomas M; Wolf, Christopher; Dirzo, Rodolfo; Everatt, Kristoffer T; Galetti, Mauro; Hayward, Matt W; Kerley, Graham I H; Levi, Taal; Lindsey, Peter A; Macdonald, David W; Malhi, Yadvinder; Painter, Luke E; Sandom, Christopher J; Terborgh, John; Van Valkenburgh, Blaire

2015-05-01

Large wild herbivores are crucial to ecosystems and human societies. We highlight the 74 largest terrestrial herbivore species on Earth (body mass ≥100 kg), the threats they face, their important and often overlooked ecosystem effects, and the conservation efforts needed to save them and their predators from extinction. Large herbivores are generally facing dramatic population declines and range contractions, such that ~60% are threatened with extinction. Nearly all threatened species are in developing countries, where major threats include hunting, land-use change, and resource depression by livestock. Loss of large herbivores can have cascading effects on other species including large carnivores, scavengers, mesoherbivores, small mammals, and ecological processes involving vegetation, hydrology, nutrient cycling, and fire regimes. The rate of large herbivore decline suggests that ever-larger swaths of the world will soon lack many of the vital ecological services these animals provide, resulting in enormous ecological and social costs.

Supplemental Carbon Dioxide Stabilizes the Upper Airway in Volunteers Anesthetized with Propofol.

PubMed

Ruscic, Katarina Jennifer; Bøgh Stokholm, Janne; Patlak, Johann; Deng, Hao; Simons, Jeroen Cedric Peter; Houle, Timothy; Peters, Jürgen; Eikermann, Matthias

2018-05-10

Propofol impairs upper airway dilator muscle tone and increases upper airway collapsibility. Preclinical studies show that carbon dioxide decreases propofol-mediated respiratory depression. We studied whether elevation of end-tidal carbon dioxide (PETCO2) via carbon dioxide insufflation reverses the airway collapsibility (primary hypothesis) and impaired genioglossus muscle electromyogram that accompany propofol anesthesia. We present a prespecified, secondary analysis of previously published experiments in 12 volunteers breathing via a high-flow respiratory circuit used to control upper airway pressure under propofol anesthesia at two levels, with the deep level titrated to suppression of motor response. Ventilation, mask pressure, negative pharyngeal pressure, upper airway closing pressure, genioglossus electromyogram, bispectral index, and change in end-expiratory lung volume were measured as a function of elevation of PETCO2 above baseline and depth of propofol anesthesia. PETCO2 augmentation dose-dependently lowered upper airway closing pressure with a decrease of 3.1 cm H2O (95% CI, 2.2 to 3.9; P < 0.001) under deep anesthesia, indicating improved upper airway stability. In parallel, the phasic genioglossus electromyogram increased by 28% (23 to 34; P < 0.001). We found that genioglossus electromyogram activity was a significant modifier of the effect of PETCO2 elevation on closing pressure (P = 0.005 for interaction term). Upper airway collapsibility induced by propofol anesthesia can be reversed in a dose-dependent manner by insufflation of supplemental carbon dioxide. This effect is at least partly mediated by increased genioglossus muscle activity.

The effect of job loss on body weight during an economic collapse.

PubMed

Jónsdóttir, Sif; Ásgeirsdóttir, Tinna Laufey

2014-07-01

Studies on the relationship between unemployment and body weight show a positive relationship between Body Mass Index (BMI) and unemployment at the individual level, while aggregate unemployment is negatively related to a population's average BMI. The aim of this study was to examine the relationship between job loss and changes in body weight following the Icelandic economic collapse of 2008. The analysis relies on a health and lifestyle survey "Heilsa og líðan", carried out by The Public Health Institute of Iceland in the years 2007 and 2009. The sample is a stratified random sample of 9,807 Icelanders between the ages of 18 and 79, with a net response rate of 42.1% for individuals responding in both waves. A linear regression model was used when estimating the relationship between job loss following the economic collapse and changes in body weight. Family income and mental health were explored as mediators. Point estimates indicated that both men and women gain less weight in the event of a job loss relative to those who retained their employment. The coefficients of job loss were only statistically significant for females, but not in the male population. The results from all three models were inconsistent with results from other studies where job loss has been found to increase body weight. However, body weight has been shown to be procyclical, and the fact that the data used were gathered during a severe economic downturn might separate these results from earlier findings.

Collapsing glomerulopathy in a young woman with APOL1 risk alleles following acute parvovirus B19 infection: a case report investigation.

PubMed

Besse, Whitney; Mansour, Sherry; Jatwani, Karan; Nast, Cynthia C; Brewster, Ursula C

2016-09-06

Collapsing Glomerulopathy (CG), also known as the collapsing variant of Focal Segmental Glomerulosclerosis (FSGS), is distinct in both its clinical severity and its pathophysiologic characteristics from other forms of FSGS. This lesion occurs disproportionally in patients carrying two APOL1 risk alleles, and is the classic histologic lesion resulting from Human Immunodeficiency Virus (HIV) infection of podocytes. Other viral infections, including parvovirus B19, and drugs such as interferon that perturb the immune system, have also been associated with CG. Despite significant advances, explaining such genetic and immune/infectious associations with causative mechanisms and supporting evidence has proven challenging. We report the case of a healthy (HIV-negative) pregnant 36 year-old Caribbean-American woman who presented with nephrotic syndrome and fetal demise in the setting of acute parvovirus B19 infection. A series of three renal biopsies and rapid clinical course showed progression from significant podocyte injury with mild light microscopy findings to classic viral-associated CG to ESRD in less than 3 months. Genetic analysis revealed two APOL1 G1 risk alleles. This is the first published case report of CG in the setting of acute parvovirus infection in a patient with two APOL1 risk allelles, and parvoviral proteins identified in renal epithelium on kidney biopsy. These findings support the causative role of parvovirus B19 infection in the development of CG on the background of APOL1 genetic risk.

Reversible Deformation of Transfusion Tracheids in Taxus baccata Is Associated with a Reversible Decrease in Leaf Hydraulic Conductance1[OPEN

PubMed Central

Zhang, Yong-Jiang; Rockwell, Fulton E.; Wheeler, James K.; Holbrook, N. Michele

2014-01-01

Declines in leaf hydraulic conductance (Kleaf) with increasing water stress have been attributed to cavitation of the leaf xylem. However, in the leaves of conifers, the reversible collapse of transfusion tracheids may provide an alternative explanation. Using Taxus baccata, a conifer species without resin, we developed a modified rehydration technique that allows the separation of declines in Kleaf into two components: one reversible and one irreversible upon relaxation of water potential to −1 MPa. We surveyed leaves at a range of water potentials for evidence of cavitation using cryo-scanning electron microscopy and quantified dehydration-induced structural changes in transfusion tracheids by cryo-fluorescence microscopy. Irreversible declines in Kleaf did not occur until leaf water potentials were more negative than −3 MPa. Declines in Kleaf between −2 and −3 MPa were reversible and accompanied by the collapse of transfusion tracheids, as evidenced by cryo-fluorescence microscopy. Based on cryo-scanning electron microscopy, cavitation of either transfusion or xylem tracheids did not contribute to declines in Kleaf in the reversible range. Moreover, the deformation of transfusion tracheids was quickly reversible, thus acting as a circuit breaker regulating the flux of water through the leaf vasculature. As transfusion tissue is present in all gymnosperms, the reversible collapse of transfusion tracheids may be a general mechanism in this group for the protection of leaf xylem from excessive loads generated in the living leaf tissue. PMID:24948828

Leadership as a predictor of stigma and practical barriers toward receiving mental health treatment: a multilevel approach.

PubMed

Britt, Thomas W; Wright, Kathleen M; Moore, Dewayne

2012-02-01

The present research examined positive and negative leadership behaviors as predictors of stigma and practical barriers to mental health treatment. Soldiers completed measures of noncommissioned officer (NCO) and officer leadership, stigma, and practical barriers to getting mental health treatment at 2, 3, and 4 months following a 15-month deployment to Afghanistan. The results revealed that positive and negative NCO and officer leader behaviors were predictive of overall stigma and barriers to care (collapsed across the three time periods), with only NCO positive and negative behaviors being uniquely predictive of stigma when included in the same model with officer behaviors. In addition, negative and positive NCO leader behaviors were predictive of stigma within participants over the course of the three month time period, and positive NCO leader behaviors were inversely related to practical barriers to mental health treatment within participants across the same time period. The results are discussed in terms of how different leader behaviors may be linked to different factors influencing a soldier's decision to seek mental health treatment.

Interpretation of Quantum Mechanics. A view of our universe

NASA Astrophysics Data System (ADS)

Lindgren, Ingvar

2009-10-01

The interpretation of quantum mechanics has been disputed ever since the advent of the theory in the 1920's. Famous are the discussions over long time between Einstein and Bohr. Einstein refused to accept the so-called Copenhagen interpretation, where the wave function collapses at a measurement and where the outcome of the measurement is essentially accidental (``God does not play dice''). Alternative interpretations have appeared, but the Copenhagen school has dominated the thoughts throughout the decades. One interesting interpretation was formulated in 1957 by Hugh Everett at Princeton, a student of John Wheeler, which abandons the wave-function collapse. In this model the universe is governed entirely by the Schrödinger equation, which does not allow for any collapse. In Everett's model after a measurement the wave function is separated into different branches that do not interact. This model was left unnoticed for long time until Bryce DeWitt took it up in 1970 and termed it ``Many-Worlds Interpretation'', a term that in some sense is misleading. Everett's model is incomplete, and it was later supplemented by the theory of decoherence, which explains how the different branches decouple as a result of the interaction with the environment. This extended model has in recent years gained increased respect, and some believe that it is the only model made available so far that is fully consistent with quantum mechanics. This interpretation can also shed some light on the development of the universe and, in particular, on the so-called Anthropic principle, which puts human beings at the center of the development.

Global warming transforms coral reef assemblages.

PubMed

Hughes, Terry P; Kerry, James T; Baird, Andrew H; Connolly, Sean R; Dietzel, Andreas; Eakin, C Mark; Heron, Scott F; Hoey, Andrew S; Hoogenboom, Mia O; Liu, Gang; McWilliam, Michael J; Pears, Rachel J; Pratchett, Morgan S; Skirving, William J; Stella, Jessica S; Torda, Gergely

2018-04-01

Global warming is rapidly emerging as a universal threat to ecological integrity and function, highlighting the urgent need for a better understanding of the impact of heat exposure on the resilience of ecosystems and the people who depend on them 1 . Here we show that in the aftermath of the record-breaking marine heatwave on the Great Barrier Reef in 2016 2 , corals began to die immediately on reefs where the accumulated heat exposure exceeded a critical threshold of degree heating weeks, which was 3-4 °C-weeks. After eight months, an exposure of 6 °C-weeks or more drove an unprecedented, regional-scale shift in the composition of coral assemblages, reflecting markedly divergent responses to heat stress by different taxa. Fast-growing staghorn and tabular corals suffered a catastrophic die-off, transforming the three-dimensionality and ecological functioning of 29% of the 3,863 reefs comprising the world's largest coral reef system. Our study bridges the gap between the theory and practice of assessing the risk of ecosystem collapse, under the emerging framework for the International Union for Conservation of Nature (IUCN) Red List of Ecosystems 3 , by rigorously defining both the initial and collapsed states, identifying the major driver of change, and establishing quantitative collapse thresholds. The increasing prevalence of post-bleaching mass mortality of corals represents a radical shift in the disturbance regimes of tropical reefs, both adding to and far exceeding the influence of recurrent cyclones and other local pulse events, presenting a fundamental challenge to the long-term future of these iconic ecosystems.

KSC-2014-3802

NASA Image and Video Library

2014-09-11

Cape Canaveral, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Kennedy Space Center Fire Chief Richard Anderson, center and Commander of the Honor Guard James Dumont, left, share emotional words at the 9/11 memorial during a ceremony held by Kennedy’s Fire and Rescue personnel. Behind the pair are members of NASA's Protective Services. Kennedy Fire and Rescue Services commemorated the 13th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Photo credit: Jim Grossmann

Utility of Lava Tubes on Other Worlds

NASA Technical Reports Server (NTRS)

Walden, Bryce E.; Billings, T. L.; York, Cheryl Lynn; Gillett, S. L.; Herbert, M. V.

1998-01-01

On Mars, as on Earth, lava tubes are found in the extensive lava fields associated with shield volcanism. Lunar lava-tube traces are located near mare-highland boundaries, giving access to a variety of minerals and other resources, including steep slopes, prominent heights for local area communications and observation, large-surface areas in shade, and abundant basalt plains suitable for landing sites, mass-drivers, surface transportation, regolith harvesting, and other uses. Methods for detecting lava tubes include visual observations of collapse trenches and skylights, ground-penetrating radar, gravimetry, magnetometry, seismography, atmospheric effects, laser, lidar, infrared, and human or robotic exploration.

KSC-2012-4919

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – NASA Kennedy Space Center’s Director Robert Cabana participates in a 9/11 memorial dedication in front of Fire Station 1 at Kennedy in Florida. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4929

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel salute or stand at attention during the 9/11 memorial dedication ceremony. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4927

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel pause for a moment of silence during the 9/11 memorial dedication ceremony. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4920

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – NASA Kennedy Space Center’s Fire and Rescue personnel stand at attention during a 9/11 memorial dedication ceremony in front of Fire Station 1 at Kennedy in Florida. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4937

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel gathered near the new 9/11 memorial after the dedication ceremony. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4921

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – NASA Kennedy Space Center’s Fire and Rescue personnel stand at attention during a 9/11 memorial dedication ceremony in front of Fire Station 1 at Kennedy in Florida. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4931

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel salute during the 9/11 memorial dedication ceremony. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

Russian scientists save American secrets

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

Sagdeev, R.

1993-05-01

Many have feared that the collapse of the Soviet Union has created new opportunities for would-be nuclear proliferators. Until recently, those dangers have seemed mainly theoretical. However, the former Soviet world was recently on the brink of breaching the Nuclear Non-Proliferation Treaty (NPT) from an unexpected corner -- the KGB. This article discusses the irony that a move to publicize Russia's files on early Soviet espionage activities in the United States would originate from the KGB. It is of note that a publication of such secrets could have been useful to countries currently trying to develop a basic nuclear bomb.

Identifying the History and Logic of Negative, Ambivalent, and Positive Responses to Literature: A Case-Study Analysis of Cultural Models

ERIC Educational Resources Information Center

Thein, Amanda Haertling

2009-01-01

This paper begins with the assumption that the interpretive practices people acquire in social worlds often transfer to their stances toward and interpretations of worlds encountered in literature (Beach, Thein, & Parks, 2007). The goal of this paper is to identify the history and logic behind one student's negative, ambivalent, and positive…

Negative Experiences as Learning Trigger: A Play Experience Empirical Research on a Game for Social Change Case Study

ERIC Educational Resources Information Center

Mariani, Ilaria; Gandolfi, Enrico

2016-01-01

This study shows the results gathered from 141 subjects playing the persuasive urban game "A Hostile World" via a post-game-experience quantitative questionnaire. The aim is to problematize and deepen the role of negative emotions (e.g., frustration, rage)--explicitly fostered by "A Hostile World" to increase empathy toward…

Effects of Cascaded Voltage Collapse and Protection of Many Induction Machine Loads upon Load Characteristics Viewed from Bulk Transmission System

NASA Astrophysics Data System (ADS)

Kumano, Teruhisa

As known well, two of the fundamental processes which give rise to voltage collapse in power systems are the on load tap changers of transformers and dynamic characteristics of loads such as induction machines. It has been well established that, comparing among these two, the former makes slower collapse while the latter makes faster. However, in realistic situations, the load level of each induction machine is not uniform and it is well expected that only a part of loads collapses first, followed by collapse process of each load which did not go into instability during the preceding collapses. In such situations the over all equivalent collapse behavior viewed from bulk transmission level becomes somewhat different from the simple collapse driven by one aggregated induction machine. This paper studies the process of cascaded voltage collapse among many induction machines by time simulation, where load distribution on a feeder line is modeled by several hundreds of induction machines and static impedance loads. It is shown that in some cases voltage collapse really cascades among induction machines, where the macroscopic load dynamics viewed from upper voltage level makes slower collapse than expected by the aggregated load model. Also shown is the effects of machine protection of induction machines, which also makes slower collapse.

Is the “ecological and economic approach for the restoration of collapsed gullies” in Southern China really economic?

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

Wang, Chengchao; Zhang, Yaoqi; Xu, Yecheng

Collapsed gully erosion constantly plagues the sustainability of rural areas in China. To control collapsed gully erosion, an ecological and economic approach, which uses tree plantation to gain economic benefits and control soil erosion, has been widely applied by local governments in Southern China. However, little is known about the economic feasibility of this new method. The objective of this study was to determine the effectiveness and economic benefits of the new method. Based on a case study in Changting County, Southeast China, two farms were selected to represent a timber tree plantation and a fruit tree plantation, respectively. Themore » Annual Capital Capitalization Method and Return on Investment (ROI) were selected to conduct cost-benefit analysis. In contrast to previous studies, we found that the new approach was far from economic. The value of the newly-built forestland in Sanzhou Village and Tufang Village is 2738 RMB ha -1 and 5477 RMB ha -1, respectively, which are extremely lower than the costs of ecological restoration. Meanwhile, the annual ROI is –3.60% and –8.90%, respectively, which is negative and also far poorer than the average value of forestry in China. The costs of conservation were substantially over the related economic benefits, and the investors would suffer from greater loss if they invested more in the conservation. Low-cost terraces with timber trees had less economic loss compared with the costly terraces with fruit tree plantation. Moreover, the cost efficiency of the new approaches in soil conservation was also greatly poorer than the conventional method. The costs of conserving one ton soil per year for conventional method, new method for planting timber trees, and planting fruit trees were 164 RMB, 696 RMB, and 11,664 RMB, respectively. Therefore, the new collapsed gully erosion control methods are uneconomic and unsuitable to be widely carried out in China in the near future.« less

Is the “ecological and economic approach for the restoration of collapsed gullies” in Southern China really economic?

DOE PAGES

Wang, Chengchao; Zhang, Yaoqi; Xu, Yecheng; ...

2015-07-31

Collapsed gully erosion constantly plagues the sustainability of rural areas in China. To control collapsed gully erosion, an ecological and economic approach, which uses tree plantation to gain economic benefits and control soil erosion, has been widely applied by local governments in Southern China. However, little is known about the economic feasibility of this new method. The objective of this study was to determine the effectiveness and economic benefits of the new method. Based on a case study in Changting County, Southeast China, two farms were selected to represent a timber tree plantation and a fruit tree plantation, respectively. Themore » Annual Capital Capitalization Method and Return on Investment (ROI) were selected to conduct cost-benefit analysis. In contrast to previous studies, we found that the new approach was far from economic. The value of the newly-built forestland in Sanzhou Village and Tufang Village is 2738 RMB ha -1 and 5477 RMB ha -1, respectively, which are extremely lower than the costs of ecological restoration. Meanwhile, the annual ROI is –3.60% and –8.90%, respectively, which is negative and also far poorer than the average value of forestry in China. The costs of conservation were substantially over the related economic benefits, and the investors would suffer from greater loss if they invested more in the conservation. Low-cost terraces with timber trees had less economic loss compared with the costly terraces with fruit tree plantation. Moreover, the cost efficiency of the new approaches in soil conservation was also greatly poorer than the conventional method. The costs of conserving one ton soil per year for conventional method, new method for planting timber trees, and planting fruit trees were 164 RMB, 696 RMB, and 11,664 RMB, respectively. Therefore, the new collapsed gully erosion control methods are uneconomic and unsuitable to be widely carried out in China in the near future.« less

Gravitational Waves from Gravitational Collapse.

PubMed

Fryer, Chris L; New, Kimberly C B

2011-01-01

Gravitational-wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion-induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars. Supplementary material is available for this article at 10.12942/lrr-2011-1.

Dynamic Control of Collapse in a Vortex Airy Beam

PubMed Central

Chen, Rui-Pin; Chew, Khian-Hooi; He, Sailing

2013-01-01

Here we study systematically the self-focusing dynamics and collapse of vortex Airy optical beams in a Kerr medium. The collapse is suppressed compared to a non-vortex Airy beam in a Kerr medium due to the existence of vortex fields. The locations of collapse depend sensitively on the initial power, vortex order, and modulation parameters. The collapse may occur in a position where the initial field is nearly zero, while no collapse appears in the region where the initial field is mainly distributed. Compared with a non-vortex Airy beam, the collapse of a vortex Airy beam can occur at a position away from the area of the initial field distribution. Our study shows the possibility of controlling and manipulating the collapse, especially the precise position of collapse, by purposely choosing appropriate initial power, vortex order or modulation parameters of a vortex Airy beam. PMID:23518858

Observations of the collapses and rebounds of millimeter-sized lithotripsy bubbles

PubMed Central

Kreider, Wayne; Crum, Lawrence A.; Bailey, Michael R.; Sapozhnikov, Oleg A.

2011-01-01

Bubbles excited by lithotripter shock waves undergo a prolonged growth followed by an inertial collapse and rebounds. In addition to the relevance for clinical lithotripsy treatments, such bubbles can be used to study the mechanics of inertial collapses. In particular, both phase change and diffusion among vapor and noncondensable gas molecules inside the bubble are known to alter the collapse dynamics of individual bubbles. Accordingly, the role of heat and mass transport during inertial collapses is explored by experimentally observing the collapses and rebounds of lithotripsy bubbles for water temperatures ranging from 20 to 60 °C and dissolved gas concentrations from 10 to 85% of saturation. Bubble responses were characterized through high-speed photography and acoustic measurements that identified the timing of individual bubble collapses. Maximum bubble diameters before and after collapse were estimated and the corresponding ratio of volumes was used to estimate the fraction of energy retained by the bubble through collapse. The rebounds demonstrated statistically significant dependencies on both dissolved gas concentration and temperature. In many observations, liquid jets indicating asymmetric bubble collapses were visible. Bubble rebounds were sensitive to these asymmetries primarily for water conditions corresponding to the most dissipative collapses. PMID:22088027

High-resolution simulations of cylindrical void collapse in energetic materials: Effect of primary and secondary collapse on initiation thresholds

NASA Astrophysics Data System (ADS)

Rai, Nirmal Kumar; Schmidt, Martin J.; Udaykumar, H. S.

2017-04-01

Void collapse in energetic materials leads to hot spot formation and enhanced sensitivity. Much recent work has been directed towards simulation of collapse-generated reactive hot spots. The resolution of voids in calculations to date has varied as have the resulting predictions of hot spot intensity. Here we determine the required resolution for reliable cylindrical void collapse calculations leading to initiation of chemical reactions. High-resolution simulations of collapse provide new insights into the mechanism of hot spot generation. It is found that initiation can occur in two different modes depending on the loading intensity: Either the initiation occurs due to jet impact at the first collapse instant or it can occur at secondary lobes at the periphery of the collapsed void. A key observation is that secondary lobe collapse leads to large local temperatures that initiate reactions. This is due to a combination of a strong blast wave from the site of primary void collapse and strong colliding jets and vortical flows generated during the collapse of the secondary lobes. The secondary lobe collapse results in a significant lowering of the predicted threshold for ignition of the energetic material. The results suggest that mesoscale simulations of void fields may suffer from significant uncertainty in threshold predictions because unresolved calculations cannot capture the secondary lobe collapse phenomenon. The implications of this uncertainty for mesoscale simulations are discussed in this paper.

Measurement of venous compliance (8-IML-1)

NASA Technical Reports Server (NTRS)

Thirsk, R. B.

1992-01-01

The prime objective of this International Microgravity Laboratory (IML-1) investigation is to measure the bulk compliance (distensibility) of the veins in the lower leg before, during, and after spaceflight. It is of particular interest whether venous compliance over the range of both positive and negative transmural pressures (various states of venous distention and collapse) changes throughout the duration of spaceflight. Information concerning the occurrence and character of compliance changes could have implications for the design of improved antigravity suits and further the understanding of inflight and postflight venous hemodynamics.

Conflict, famine and the arms trade.

PubMed

Judd, F

1995-01-01

Armed conflict has had horrendous humanitarian effects, causing 22 million deaths, over 80 per cent of them civilian, since 1945 and resulting today in 19 million refugees and 24 million displaced persons. War results in economic collapse, and high levels of military spending decrease regional stability. Benefits to the producers are limited or negative and developed countries should diversify away from arms production. There is a need for greater awareness in the developed countries, an end to the secrecy besetting the arms trade, and restructuring of the industry. A Code of Conduct governing arms exports is proposed.

Positive and Negative Feedbacks and Free-Scale Pattern Distribution in Rural-Population Dynamics

PubMed Central

Alados, Concepción L.; Errea, Paz; Gartzia, Maite; Saiz, Hugo; Escós, Juan

2014-01-01

Depopulation of rural areas is a widespread phenomenon that has occurred in most industrialized countries, and has contributed significantly to a reduction in the productivity of agro-ecological resources. In this study, we identified the main trends in the dynamics of rural populations in the Central Pyrenees in the 20th C and early 21st C, and used density independent and density dependent models and identified the main factors that have influenced the dynamics. In addition, we investigated the change in the power law distribution of population size in those periods. Populations exhibited density-dependent positive feedback between 1960 and 2010, and a long-term positive correlation between agricultural activity and population size, which has resulted in a free-scale population distribution that has been disrupted by the collapse of the traditional agricultural society and by emigration to the industrialized cities. We concluded that complex socio-ecological systems that have strong feedback mechanisms can contribute to disruptive population collapses, which can be identified by changes in the pattern of population distribution. PMID:25474704

Financial market response to extreme events indicating climatic change

NASA Astrophysics Data System (ADS)

Anttila-Hughes, J. K.

2016-05-01

A variety of recent extreme climatic events are considered to be strong evidence that the climate is warming, but these incremental advances in certainty often seem ignored by non-scientists. I identify two unusual types of events that are considered to be evidence of climate change, announcements by NASA that the global annual average temperature has set a new record, and the sudden collapse of major polar ice shelves, and then conduct an event study to test whether news of these events changes investors' valuation of energy companies, a subset of firms whose future performance is closely tied to climate change. I find evidence that both classes of events have influenced energy stock prices since the 1990s, with record temperature announcements on average associated with negative returns and ice shelf collapses associated with positive returns. I identify a variety of plausible mechanisms that may be driving these differential responses, discuss implications for energy markets' views on long-term regulatory risk, and conclude that investors not only pay attention to scientifically significant climate events, but discriminate between signals carrying different information about the nature of climatic change.

Macroion induced dehydration of weak polyelectrolyte brushes

NASA Astrophysics Data System (ADS)

Zheng, Zhongli; Zhu, Y. Elaine

2014-03-01

The interaction of macroions, including polyelectrolytes, DNAs, and proteins, with polymer and cellular surfaces is critically related to many biomolecular activities, such as protein adsorption and DNA hybridization at probe surfaces. In an experimental approach to examine the macroion electrostatic interaction with a polymer surface while minimizing the long-debated hydrophobic interaction, we study the interaction of molybdenum-based inorganic polyoxometalate (POM) nanoclusters carrying 42 negative charges as model hydrophilic macroions with surface-tethered poly-2-vinylpyridine (P2VP) brushes immersed in aqueous solutions. By AFM, QCM, and contact goniometer, we have observed the collapse of P2VP chains by adding POM macroions at a constant pH. Surprisingly, added POM macroions can cause the shift of swollen-to-collapse transition pH to a lower value, in contrast to the shift to high pH value by adding simple monovalent salts. At sufficiently high POM concentration, a stable POM-P2VP composite layer, showing little dependence on solution pH and additional salts, can be formed, suggesting a simple route to construct meso-porous polymer membranes.

Collapse of the surface dusty plasma waves under the plasma-beam instability

NASA Astrophysics Data System (ADS)

Grimalsky, Volodymyr; Kotsarenko, Anatoliy; Koshevaya, Svetlana; Escobedo-A., Jesus

2017-12-01

The nonlinear dynamics of the dusty plasma-dusty beam instability is investigated in the dusty plasma waveguides bounded by dielectrics. The dusty plasma includes the positive ions as the light component and the negative dust as the heavy component. A beam of dust particles moves along the waveguide. The set of hydrodynamic equations for the dust and beam particles, namely, the continuity equations and the equations for the momentum jointly with the Poisson one are used. The Boltzmann distribution is used for the ions. The electric and hydrodynamic boundary conditions are applied at the interfaces. The simulations have demonstrated that the dusty sound waves of small amplitudes are the subject to amplification with a high increment due to the convective instability, even when the concentration of the beam particles is ≤0.1 of the uniform dust concentration. The amplification very rapidly transits to the regime of strong surface nonlinearity, and near the interfaces the variations of the dust concentration reach extremely high values, where the collapse of the beam dust component occurs.

Fate of inflation and the natural reduction of vacuum energy

NASA Astrophysics Data System (ADS)

Nakamichi, Akika; Morikawa, Masahiro

2014-04-01

In the standard cosmology, an artificial fine tuning of the potential is inevitable for vanishing cosmological constant, though slow-rolling uniform scalar field easily causes cosmic inflation. We focus on the general fact that any potential with negative region can temporally halt the cosmic expansion at the end of inflation, where the field tends to diverge. This violent evolution naturally causes particle production and strong instability of the uniform configuration of the fields. Decaying of this uniform scalar field would leave vanishing cosmological constant as well as locally collapsed objects. The universe then continues to evolve into the standard Freedman model. We study the detail of the instability, based on the linear analysis, and the subsequent fate of the scalar field, based on the non-linear numerical analysis. The collapsed scalar field would easily exceed the Kaup limiting mass and forms primordial black holes, which may play an important role in galaxy formation in later stages of cosmic expansion. We systematically describe the above scenario by identifying the scalar field as the boson field condensation (BEC) and the inflation as the process of phase transition of them.

Effects of Nonlinear Inhomogeneity on the Cosmic Expansion with Numerical Relativity.

PubMed

Bentivegna, Eloisa; Bruni, Marco

2016-06-24

We construct a three-dimensional, fully relativistic numerical model of a universe filled with an inhomogeneous pressureless fluid, starting from initial data that represent a perturbation of the Einstein-de Sitter model. We then measure the departure of the average expansion rate with respect to this homogeneous and isotropic reference model, comparing local quantities to the predictions of linear perturbation theory. We find that collapsing perturbations reach the turnaround point much earlier than expected from the reference spherical top-hat collapse model and that the local deviation of the expansion rate from the homogeneous one can be as high as 28% at an underdensity, for an initial density contrast of 10^{-2}. We then study, for the first time, the exact behavior of the backreaction term Q_{D}. We find that, for small values of the initial perturbations, this term exhibits a 1/a scaling, and that it is negative with a linearly growing absolute value for larger perturbation amplitudes, thereby contributing to an overall deceleration of the expansion. Its magnitude, on the other hand, remains very small even for relatively large perturbations.

Mercury Cavitation Phenomenon in Pulsed Spallation Neutron Sources

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

Futakawa, Masatoshi; Naoe, Takashi; Kawai, Masayoshi

2008-06-24

Innovative researches will be performed at Materials and Life Science Experimental Facility in J-PARC, in which a mercury target system will be installed as MW-class pulse spallation neutron sources. Proton beams will be injected into mercury target to induce the spallation reaction. At the moment the intense proton beam hits the target, pressure waves are generated in the mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel leading to negative pressure that may cause cavitation along the vessel wall. Localized impacts by micro-jets and/or shock waves which are caused by cavitation bubble collapse imposemore » pitting damage on the vessel wall. The pitting damage which degrades the structural integrity of target vessels is a crucial issue for high power mercury targets. Micro-gas-bubbles injection into mercury may be useful to mitigate the pressure wave and the pitting damage. The visualization of cavitation-bubble and gas-bubble collapse behaviors was carried out by using a high-speed video camera. The differences between them are recognized.« less

Hydrostatic pressure effects on the structural and electronicproperties of carbon nanotubes

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

Capaz,Rodrigo B.; Spataru, Catalin D.; Tangney, Paul

2004-03-15

We study the structural and electronic properties ofisolated single-wall carbon nanotubes (SWNTs) under hydrostatic pressureusing a combination of theoretical techniques: continuum elasticitymodels, classical molecular dynamics simulations, tight-bindingelectronic structure methods, and first-principles total energycalculations within the density-functional and pseudopotentialframeworks. For pressures below a certain critica pressure Pc, the SWNTs'structure remains cylindrical and the Kohn-Sham energy gaps ofsemiconducting SWNTs have either positive or negative pressurecoefficients depending on the value of (n,m) with a distinct "family" (ofthe same n-m) behavior. The diameter and chirality dependence of thepressure coefficients can be described by a simple analytical expression.At Pc, molecular-dynamics simulations predict that isolated SWNTsmore » undergoa pressure-induced symmetry-breaking transformation from a cylindricalshape to a collapsed geometry. This transition is described by a simpleelastic model as arising from the competition between the bond-bendingand PV terms in the enthalpy. The good agreement between calculated andexperimental values of Pc provides a strong support to the "collapse"interpretation of the experimental transitions in bundles.« less

ARTD1/PARP1 negatively regulates glycolysis by inhibiting hexokinase 1 independent of NAD+ depletion

PubMed Central

Fouquerel, Elise; Goellner, Eva M.; Yu, Zhongxun; Gagné, Jean-Philippe; de Moura, Michelle Barbi; Feinstein, Tim; Wheeler, David; Redpath, Philip; Li, Jianfeng; Romero, Guillermo; Migaud, Marie; Van Houten, Bennett; Poirier, Guy G.; Sobol, Robert W.

2014-01-01

Summary ARTD1 (PARP1) is a key enzyme involved in DNA repair by synthesizing poly(ADP-ribose) (PAR) in response to strand breaks and plays an important role in cell death following excessive DNA damage. ARTD1-induced cell death is associated with NAD+ depletion and ATP loss, however the molecular mechanism of ARTD1-mediated energy collapse remains elusive. Using real-time metabolic measurements, we directly compared the effects of ARTD1 activation and direct NAD+ depletion. We found that ARTD1-mediated PAR synthesis, but not direct NAD+ depletion, resulted in a block to glycolysis and ATP loss. We then established a proteomics based PAR-interactome after DNA damage and identified hexokinase 1 (HK1) as a PAR binding protein. HK1 activity is suppressed following nuclear ARTD1 activation and binding by PAR. These findings help explain how prolonged activation of ARTD1 triggers energy collapse and cell death, revealing new insight on the importance of nucleus to mitochondria communication via ARTD1 activation. PMID:25220464

Extending Femtosecond Filamentation of High Power Laser Propagating in the Atmosphere

NASA Astrophysics Data System (ADS)

Eisenmann, Shmuel; Sivan, Yonatan; Fibich, Gadi; Zigler, Arie

2008-06-01

We show experimentally for ultrashort laser pulses propagating in air, that the filamentation distance of intense laser pulses in the atmosphere can be extended and controlled with a simple double-lens setup. Using this method we were able to achieve a 20-fold delay of the filamentation distance of non-chirped 120 fs pulses propagating in air, from 16 m to 330 m. At 330 m, the collapsing pulse is sufficiently powerful to create plasma filaments. We also show that the scatter of the filaments at 330 m can be significantly reduced by tilting the second lens. We derive a simple formula for the filamentation distance, and confirm its agreement with the experimental results. We also observe that delaying the onset of filamentation increases the filament length. To the best of our knowledge, this is the longest distance reported in the literature at which plasma filaments were created and controlled. Finally, we show that the peak power at the onset of collapse is significantly higher with the double-lens setup, compared with the standard negative chirping approach.

Alveolar derecruitment and collapse induration as crucial mechanisms in lung injury and fibrosis.

PubMed

Lutz, Dennis; Gazdhar, Amiq; Lopez-Rodriguez, Elena; Ruppert, Clemens; Mahavadi, Poornima; Günther, Andreas; Klepetko, Walter; Bates, Jason H; Smith, Bradford; Geiser, Thomas; Ochs, Matthias; Knudsen, Lars

2015-02-01

Idiopathic pulmonary fibrosis (IPF) and bleomycin-induced pulmonary fibrosis are associated with surfactant system dysfunction, alveolar collapse (derecruitment), and collapse induration (irreversible collapse). These events play undefined roles in the loss of lung function. The purpose of this study was to quantify how surfactant inactivation, alveolar collapse, and collapse induration lead to degradation of lung function. Design-based stereology and invasive pulmonary function tests were performed 1, 3, 7, and 14 days after intratracheal bleomycin-instillation in rats. The number and size of open alveoli was correlated to mechanical properties. Active surfactant subtypes declined by Day 1, associated with a progressive alveolar derecruitment and a decrease in compliance. Alveolar epithelial damage was more pronounced in closed alveoli compared with ventilated alveoli. Collapse induration occurred on Day 7 and Day 14 as indicated by collapsed alveoli overgrown by a hyperplastic alveolar epithelium. This pathophysiology was also observed for the first time in human IPF lung explants. Before the onset of collapse induration, distal airspaces were easily recruited, and lung elastance could be kept low after recruitment by positive end-expiratory pressure (PEEP). At later time points, the recruitable fraction of the lung was reduced by collapse induration, causing elastance to be elevated at high levels of PEEP. Surfactant inactivation leading to alveolar collapse and subsequent collapse induration might be the primary pathway for the loss of alveoli in this animal model. Loss of alveoli is highly correlated with the degradation of lung function. Our ultrastructural observations suggest that collapse induration is important in human IPF.

Delineation of a collapse feature in a noisy environment using a multichannel surface wave technique

USGS Publications Warehouse

Xia, J.; Chen, C.; Li, P.H.; Lewis, M.J.

2004-01-01

A collapse developed at Calvert Cliffs Nuclear Power Plant, Maryland, in early 2001. The location of the collapse was over a groundwater drainage system pipe buried at an elevation of +0??9 m (reference is to Chesapeake Bay level). The cause of the collapse was a subsurface drain pipe that collapsed because of saltwater corrosion of the corrugated metal pipe. The inflow/outflow of sea water and groundwater flow caused soil to be removed from the area where the pipe collapsed. To prevent damage to nearby structures, the collapse was quickly filled with uncompacted sand and gravel (???36000 kg). However, the plant had an immediate need to determine whether more underground voids existed. A high-frequency multichannel surface-wave survey technique was conducted to define the zone affected by the collapse. Although the surface-wave survey at Calvert Cliffs Nuclear Power Plant was conducted at a noise level 50-100 times higher than the normal environment for a shallow seismic survey, the shear (S)-wave velocity field calculated from surface-wave data delineated a possible zone affected by the collapse. The S-wave velocity field showed chimney-shaped low-velocity anomalies that were directly related to the collapse. Based on S-wave velocity field maps, a potential zone affected by the collapse was tentatively defined.

The origins of dragon-kings and their occurrence in society

NASA Astrophysics Data System (ADS)

Malkov, Artemy; Zinkina, Julia; Korotayev, Andrey

2012-11-01

A society is a medium with a complex structure of one-to-one relations between people. Those could be relations between friends, wife-husband relationships, relations between business partners, and so on. At a certain level of analysis, a society can be regarded as a gigantic maze constituted of one-to-one relationships between people. From a physical standpoint it can be considered as a highly porous medium. Such media are widely known for their outstanding properties and effects like self-organized criticality, percolation, power-law distribution of network cluster sizes, etc. In these media supercritical events, referred to as dragon-kings, may occur in two cases: when increasing stress is applied to a system (self-organized criticality scenario) or when increasing conductivity of a system is observed (percolation scenario). In social applications the first scenario is typical for negative effects: crises, wars, revolutions, financial breakdowns, state collapses, etc. The second scenario is more typical for positive effects like emergence of cities, growth of firms, population blow-ups, economic miracles, technology diffusion, social network formation, etc. If both conditions (increasing stress and increasing conductivity) are observed together, then absolutely miraculous dragon-king effects can occur that involve most human society. Historical examples of this effect are the emergence of the Mongol Empire, world religions, World War II, and the explosive proliferation of global internet services. This article describes these two scenarios in detail beginning with an overview of historical dragon-king events and phenomena starting from the early human history till the last decades and concluding with an analysis of their possible near future consequences on our global society. Thus we demonstrate that in social systems dragon-king is not a random outlier unexplainable by power-law statistics, but a natural effect. It is a very large cluster in a porous percolation medium. It occurs as a result of changes in external conditions, such as supercritical load, increase in system elements’ sensitivity, or system connectivity growth.

Collapse of Corroded Pipelines under Combined Tension and External Pressure

PubMed Central

Ye, Hao; Yan, Sunting; Jin, Zhijiang

2016-01-01

In this work, collapse of corroded pipeline under combined external pressure and tension is investigated through numerical method. Axially uniform corrosion with symmetric imperfections is firstly considered. After verifying with existing experimental results, the finite element model is used to study the effect of tension on collapse pressure. An extensive parametric study is carried out using Python script and FORTRAN subroutine to investigate the influence of geometric parameters on the collapse behavior under combined loads. The results are used to develop an empirical equation for estimating the collapse pressure under tension. In addition, the effects of loading path, initial imperfection length, yielding anisotropy and corrosion defect length on the collapse behavior are also investigated. It is found that tension has a significant influence on collapse pressure of corroded pipelines. Loading path and anisotropic yielding are also important factors affecting the collapse behavior. For pipelines with relatively long corrosion defect, axially uniform corrosion models could be used to estimate the collapse pressure. PMID:27111544

Comparing solvophobic and multivalent induced collapse in polyelectrolyte brushes

DOE PAGES

Jackson, Nicholas E.; Brettmann, Blair K.; Vishwanath, Venkatram; ...

2017-02-03

Here, coarse-grained molecular dynamics enhanced by free-energy sampling methods is used to examine the roles of solvophobicity and multivalent salts on polyelectrolyte brush collapse. Specifically, we demonstrate that while ostensibly similar, solvophobic collapsed brushes and multivalent-ion collapsed brushes exhibit distinct mechanistic and structural features. Notably, multivalent-induced heterogeneous brush collapse is observed under good solvent polymer backbone conditions, demonstrating that the mechanism of multivalent collapse is not contingent upon a solvophobic backbone. Umbrella sampling of the potential of mean-force (PMF) between two individual brush strands confirms this analysis, revealing starkly different PMFs under solvophobic and multivalent conditions, suggesting the role ofmore » multivalent “bridging” as the discriminating feature in trivalent collapse. Structurally, multivalent ions show a propensity for nucleating order within collapsed brushes, whereas poor-solvent collapsed brushes are more disordered; this difference is traced to the existence of a metastable PMF minimum for poor solvent conditions, and a global PMF minimum for trivalent systems, under experimentally relevant conditions.« less

Comparing solvophobic and multivalent induced collapse in polyelectrolyte brushes

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

Jackson, Nicholas E.; Brettmann, Blair K.; Vishwanath, Venkatram

Here, coarse-grained molecular dynamics enhanced by free-energy sampling methods is used to examine the roles of solvophobicity and multivalent salts on polyelectrolyte brush collapse. Specifically, we demonstrate that while ostensibly similar, solvophobic collapsed brushes and multivalent-ion collapsed brushes exhibit distinct mechanistic and structural features. Notably, multivalent-induced heterogeneous brush collapse is observed under good solvent polymer backbone conditions, demonstrating that the mechanism of multivalent collapse is not contingent upon a solvophobic backbone. Umbrella sampling of the potential of mean-force (PMF) between two individual brush strands confirms this analysis, revealing starkly different PMFs under solvophobic and multivalent conditions, suggesting the role ofmore » multivalent “bridging” as the discriminating feature in trivalent collapse. Structurally, multivalent ions show a propensity for nucleating order within collapsed brushes, whereas poor-solvent collapsed brushes are more disordered; this difference is traced to the existence of a metastable PMF minimum for poor solvent conditions, and a global PMF minimum for trivalent systems, under experimentally relevant conditions.« less

Computed tomography of lobar collapse: 2. Collapse in the absence of endobronchial obstruction

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

Naidich, D.P.; McCauley, D.I.; Khouri, N.F.

1983-10-01

The computed tomographic appearance of collapse without endobronchial obstruction is reviewed. These 57 cases were classified by the etiology of collapse. The largest group consisted of 29 patients with passive atelectasis, i.e., collapse secondary to fluid, air, or both in the pleural space. Twenty-three of 29 proved secondary to malignant pleural disease. Computed tomography accurately predicted a malignant etiology in 22 of 23 cases. The second largest group of patients had lobar collapse secondary to cicatrization from chronic inflammation. In all cases the underlying etiology was tuberculosis. Radiation caused adhesive atelectasis in six patients secondary to a lack of productionmore » of surfactant. In each case a sharp line of demarcation could be defined between normal and abnormal collapsed pulmonary parenchyma. Three cases of unchecked tumor growth caused a peripheral form of collapse (replacement atelectasis). This form of collapse was characterized by an absence of endobronchial obstruction and extensive tumor not delineated by the normal boundaries of the pulmonary lobes.« less

A potential link among biogenic amines-based pesticides, learning and memory, and colony collapse disorder: a unique hypothesis.

PubMed

Farooqui, Tahira

2013-01-01

Pesticides are substances that have been widely used throughout the world to kill, repel, or control organisms such as certain forms of plants or animals considered as pests. Depending on their type, dose, and persistence in the environment, they can have impact even on non-target species such as beneficial insects (honeybees) in different ways, including reduction in their survival rate and interference with their reproduction process. Honeybee Apis mellifera is a major pollinator and has substantial economical and ecological values. Colony collapse disorder (CCD) is a mysterious phenomenon in which adult honeybee workers suddenly abandon from their hives, leaving behind food, brood, and queen. It is lately drawing a lot of attention due to pollination crisis as well as global agriculture and medical demands. If the problem of CCD is not resolved soon enough, this could have a major impact on food industry affecting world's economy a big time. Causes of CCD are not known. In this overview, I discuss CCD, biogenic amines-based-pesticides (neonicotinoids and formamidines), and their disruptive effects on biogenic amine signaling causing olfactory dysfunction in honeybees. According to my hypothesis, chronic exposure of biogenic amines-based-pesticides to honeybee foragers in hives and agricultural fields can disrupt neural cholinergic and octopaminergic signaling. Abnormality in biogenic amines-mediated neuronal signaling impairs their olfactory learning and memory, therefore foragers do not return to their hive - a possible cause of CCD. This overview is an attempt to discuss a hypothetical link among biogenic amines-based pesticides, olfactory learning and memory, and CCD. Copyright © 2012 Elsevier Ltd. All rights reserved.

Chapter A. The Loma Prieta, California, Earthquake of October 17, 1989 - Lifelines

USGS Publications Warehouse

Schiff, Anshel J.

1998-01-01

To the general public who had their televisions tuned to watch the World Series, the 1989 Loma Prieta earthquake was a lifelines earthquake. It was the images seen around the world of the collapsed Cypress Street viaduct, with the frantic and heroic efforts to pull survivors from the structure that was billowing smoke; the collapsed section of the San Francisco-Oakland Bay Bridge and subsequent home video of a car plunging off the open span; and the spectacular fire in the Marina District of San Francisco fed by a broken gasline. To many of the residents of the San Francisco Bay region, the relation of lifelines to the earthquake was characterized by sitting in the dark because of power outage, the inability to make telephone calls because of network congestion, and the slow and snarled traffic. Had the public been aware of the actions of the engineers and tradespeople working for the utilities and other lifeline organizations on the emergency response and restoration of lifelines, the lifeline characteristics of this earthquake would have been even more significant. Unobserved by the public were the warlike devastation in several electrical-power substations, the 13 miles of gas-distribution lines that had to be replaced in several communities, and the more than 1,200 leaks and breaks in water mains and service connections that had to be excavated and repaired. Like the 1971 San Fernando, Calif., earthquake, which was a seminal event for activity to improve the earthquake performance of lifelines, the 1989 Loma Prieta earthquake demonstrated that the tasks of preparing lifelines in 'earthquake country' were incomplete-indeed, new lessons had to be learned.

Scientific foundations for an IUCN Red List of ecosystems.

PubMed

Keith, David A; Rodríguez, Jon Paul; Rodríguez-Clark, Kathryn M; Nicholson, Emily; Aapala, Kaisu; Alonso, Alfonso; Asmussen, Marianne; Bachman, Steven; Basset, Alberto; Barrow, Edmund G; Benson, John S; Bishop, Melanie J; Bonifacio, Ronald; Brooks, Thomas M; Burgman, Mark A; Comer, Patrick; Comín, Francisco A; Essl, Franz; Faber-Langendoen, Don; Fairweather, Peter G; Holdaway, Robert J; Jennings, Michael; Kingsford, Richard T; Lester, Rebecca E; Mac Nally, Ralph; McCarthy, Michael A; Moat, Justin; Oliveira-Miranda, María A; Pisanu, Phil; Poulin, Brigitte; Regan, Tracey J; Riecken, Uwe; Spalding, Mark D; Zambrano-Martínez, Sergio

2013-01-01

An understanding of risks to biodiversity is needed for planning action to slow current rates of decline and secure ecosystem services for future human use. Although the IUCN Red List criteria provide an effective assessment protocol for species, a standard global assessment of risks to higher levels of biodiversity is currently limited. In 2008, IUCN initiated development of risk assessment criteria to support a global Red List of ecosystems. We present a new conceptual model for ecosystem risk assessment founded on a synthesis of relevant ecological theories. To support the model, we review key elements of ecosystem definition and introduce the concept of ecosystem collapse, an analogue of species extinction. The model identifies four distributional and functional symptoms of ecosystem risk as a basis for assessment criteria: A) rates of decline in ecosystem distribution; B) restricted distributions with continuing declines or threats; C) rates of environmental (abiotic) degradation; and D) rates of disruption to biotic processes. A fifth criterion, E) quantitative estimates of the risk of ecosystem collapse, enables integrated assessment of multiple processes and provides a conceptual anchor for the other criteria. We present the theoretical rationale for the construction and interpretation of each criterion. The assessment protocol and threat categories mirror those of the IUCN Red List of species. A trial of the protocol on terrestrial, subterranean, freshwater and marine ecosystems from around the world shows that its concepts are workable and its outcomes are robust, that required data are available, and that results are consistent with assessments carried out by local experts and authorities. The new protocol provides a consistent, practical and theoretically grounded framework for establishing a systematic Red List of the world's ecosystems. This will complement the Red List of species and strengthen global capacity to report on and monitor the status of biodiversity.

History of internal fixation with plates (part 2): new developments after World War II; compressing plates and locked plates.

PubMed

Hernigou, Philippe; Pariat, Jacques

2017-07-01

The first techniques of operative fracture with plates were developed in the 19th century. In fact, at the beginning these methods consisted of an open reduction of the fracture usually followed by a very unstable fixation. As a consequence, the fracture had to be opened with a real risk of (sometimes lethal) infection, and due to unstable fixation, protection with a cast was often necessary. During the period between World Wars I and II, plates for fracture fixation developed with great variety. It became increasingly recognised that, because a fracture of a long bone normally heals with minimal resorption at the bone ends, this may result in slight shortening and collapse, so a very rigid plate might prevent such collapse. However, as a consequence, delayed healing was observed unless the patient was lucky enough to have the plate break. One way of dealing with this was to use a slotted plate in which the screws could move axially, but the really important advance was recognition of the role of compression. After the first description of compression by Danis with a "coapteur", Bagby and Müller with the AO improved the technique of compression. The classic dynamic compression plates from the 1970s were the key to a very rigid fixation, leading to primary bone healing. Nevertheless, the use of strong plates resulted in delayed union and the osteoporosis, cancellous bone, comminution, and/or pathological bone resulted in some failures due to insufficient stability. Finally, new devices represented by locking plates increased the stability, contributing to the principles of a more biological osteosynthesis while giving enough stability to allow immediate full weight bearing in some patients.

A case study of the response of the magnetosphere to changes in the interplanetary medium

NASA Technical Reports Server (NTRS)

Rostoker, G.; Baumjohann, W.; Russell, C. T.

1983-01-01

A detailed analysis of world-wide ground based magnetometer data is presented, together with information on the plasma and magnetic field properties of the interplanetary medium and magnetosheath obtained from the ISEE 1 and 2 and IMP 8 spacecraft. The event concerned exhibited an interval of relatively stable southward IMF followed by a sharp northward turning. It is pointed out that during the interval of southward IMF there were occasional transient northward turnings with significant substorm expansive phase activity appearing to be triggered by these transient northward turnings. The final northward turning of the IMF was linked with an episode of strong magnetospheric substorm expansive phase activity after which the level of high latitude magnetic activity declined to a low level. Evidence is presented indicating that the driven system auroral electrojets begin to decay at the time of the northward turning of the IMF, even as the substorm expansive phase activity is initiated in the midnight sector. The collapse of the substorm current wedge during the final decay of high latitude activity is described in some detail, and it is shown that this collapse occurs progressively from east to west in a series of impulsive episodes.

Using multiple lines of evidence to assess the risk of ecosystem collapse

PubMed Central

Regan, Tracey J.; Dinh, Minh Ngoc; Ferrari, Renata; Keith, David A.; Lester, Rebecca; Mouillot, David; Murray, Nicholas J.; Nguyen, Hoang Anh; Nicholson, Emily

2017-01-01

Effective ecosystem risk assessment relies on a conceptual understanding of ecosystem dynamics and the synthesis of multiple lines of evidence. Risk assessment protocols and ecosystem models integrate limited observational data with threat scenarios, making them valuable tools for monitoring ecosystem status and diagnosing key mechanisms of decline to be addressed by management. We applied the IUCN Red List of Ecosystems criteria to quantify the risk of collapse of the Meso-American Reef, a unique ecosystem containing the second longest barrier reef in the world. We collated a wide array of empirical data (field and remotely sensed), and used a stochastic ecosystem model to backcast past ecosystem dynamics, as well as forecast future ecosystem dynamics under 11 scenarios of threat. The ecosystem is at high risk from mass bleaching in the coming decades, with compounding effects of ocean acidification, hurricanes, pollution and fishing. The overall status of the ecosystem is Critically Endangered (plausibly Vulnerable to Critically Endangered), with notable differences among Red List criteria and data types in detecting the most severe symptoms of risk. Our case study provides a template for assessing risks to coral reefs and for further application of ecosystem models in risk assessment. PMID:28931744

Environmental predictors of pre-European deforestation on Pacific islands.

PubMed

Rolett, Barry; Diamond, Jared

2004-09-23

Some Pacific island societies, such as those of Easter Island and Mangareva, inadvertently contributed to their own collapse by causing massive deforestation. Others retained forest cover and survived. How can those fateful differences be explained? Although the answers undoubtedly involve both different cultural responses of peoples and different susceptibilities of environments, how can one determine which environmental factors predispose towards deforestation and which towards replacement of native trees with useful introduced tree species? Here we code European-contact conditions and nine environmental variables for 81 sites on 69 Pacific islands from Yap in the west to Easter in the east, and from Hawaii in the north to New Zealand in the south. We thereby detect statistical decreases in deforestation and/or forest replacement with island rainfall, elevation, area, volcanic ash fallout, Asian dust transport and makatea terrain (uplifted reef), and increases with latitude, age and isolation. Comparative analyses of deforestation therefore lend themselves to much more detailed interpretations than previously possible. These results might be relevant to similar deforestation-associated collapses (for example, Fertile Crescent, Maya and Anasazi) or the lack thereof (Japan and highland New Guinea) elsewhere in the world.

Policies and Livestock Systems Driving Brucellosis Re-emergence in Kazakhstan.

PubMed

Beauvais, Wendy; Coker, Richard; Nurtazina, Gulzhan; Guitian, Javier

2017-06-01

Brucellosis is a considerable public health and economic burden in many areas of the world including sub-Saharan Africa, the Middle East and former USSR countries. The collapse of the USSR has been cited as a driver for re-emergence of diseases including brucellosis, and human incidence rates in the former Soviet republics have been estimated as high as 88 per 100,000 per year. The aim of this paper is to examine the historical trends in brucellosis in Kazakhstan and to explore how livestock systems, veterinary services and control policies may have influenced them. In conclusion, a brucellosis epidemic most likely began before the collapse of the USSR and high livestock densities may have played an important role. Changes to the livestock systems in Kazakhstan, as well as other factors, are likely to have an impact on the success of brucellosis policies in the future. Incentives and practicalities of different policies in smallholder settings should be considered. However, the lack of reliable estimates of brucellosis prevalence and difficulties in understanding exactly how policy is being applied in Kazakhstan, which is a vast country with low population density, prevent firm conclusions from being drawn.

Environmental change and the conversion of permanently frozen ground to wetlands

NASA Astrophysics Data System (ADS)

Neumann, R. B.; Moorberg, C.; Turner, J.; Wong, A.; Waldrop, M. P.; Euskirchen, E. S.; Edgar, C.; Turetsky, M. R.

2017-12-01

Much of the land around the arctic is permanently frozen, even in the summer. However, because the world is getting warmer, this frozen ground, known as permafrost, is thawing. When permafrost thaws, the ground collapses and sinks, and often a wetland forms within the collapsed area. This conversion of a permanently frozen landscape to a wetland changes the exchange of greenhouse gases between the land and atmosphere, which can, in turn, impact global temperatures and environmental conditions. Wetlands pull carbon dioxide out of the atmosphere because they support the growth of many plants. This uptake of atmospheric carbon dioxide by wetlands helps reduce global warming. However, wetlands also release methane into the atmosphere, which is a potent greenhouse gas — more potent than carbon dioxide. The net effect on global temperatures and environmental conditions depends on the balance between wetland uptake of atmospheric carbon dioxide and release of methane. We are measuring the exchange of these two greenhouse gases between the land and atmosphere in a wetland that formed after permafrost thawed so we can know how global temperatures and environmental conditions will change as northern landscapes continue to thaw.

Considerable MHC Diversity Suggests That the Functional Extinction of Baiji Is Not Related to Population Genetic Collapse

PubMed Central

Xu, Shixia; Ju, Jianfeng; Zhou, Xuming; Wang, Lian; Zhou, Kaiya; Yang, Guang

2012-01-01

To further extend our understanding of the mechanism causing the current nearly extinct status of the baiji (Lipotes vexillifer), one of the most critically endangered species in the world, genetic diversity at the major histocompatibility complex (MHC) class II DRB locus was investigated in the baiji. Nine highly divergent DRB alleles were identified in 17 samples, with an average of 28.4 (13.2%) nucleotide difference and 16.7 (23.5%) amino acid difference between alleles. The unexpectedly high levels of DRB allelic diversity in the baiji may partly be attributable to its evolutionary adaptations to the freshwater environment which is regarded to have a higher parasite diversity compared to the marine environment. In addition, balancing selection was found to be the main mechanisms in generating sequence diversity at baiji DRB gene. Considerable sequence variation at the adaptive MHC genes despite of significant loss of neutral genetic variation in baiji genome might suggest that intense selection has overpowered random genetic drift as the main evolutionary forces, which further suggested that the critically endangered or nearly extinct status of the baiji is not an outcome of genetic collapse. PMID:22272349

Using multiple lines of evidence to assess the risk of ecosystem collapse.

PubMed

Bland, Lucie M; Regan, Tracey J; Dinh, Minh Ngoc; Ferrari, Renata; Keith, David A; Lester, Rebecca; Mouillot, David; Murray, Nicholas J; Nguyen, Hoang Anh; Nicholson, Emily

2017-09-27

Effective ecosystem risk assessment relies on a conceptual understanding of ecosystem dynamics and the synthesis of multiple lines of evidence. Risk assessment protocols and ecosystem models integrate limited observational data with threat scenarios, making them valuable tools for monitoring ecosystem status and diagnosing key mechanisms of decline to be addressed by management. We applied the IUCN Red List of Ecosystems criteria to quantify the risk of collapse of the Meso-American Reef, a unique ecosystem containing the second longest barrier reef in the world. We collated a wide array of empirical data (field and remotely sensed), and used a stochastic ecosystem model to backcast past ecosystem dynamics, as well as forecast future ecosystem dynamics under 11 scenarios of threat. The ecosystem is at high risk from mass bleaching in the coming decades, with compounding effects of ocean acidification, hurricanes, pollution and fishing. The overall status of the ecosystem is Critically Endangered (plausibly Vulnerable to Critically Endangered), with notable differences among Red List criteria and data types in detecting the most severe symptoms of risk. Our case study provides a template for assessing risks to coral reefs and for further application of ecosystem models in risk assessment. © 2017 The Authors.

New York City Department of Health response to terrorist attack, September 11, 2001.

PubMed

2001-09-28

In response to two jet aircraft crashing into and causing the collapse of the 110-storied World Trade Center (WTC) towers and the subsequent destruction of nearby portions of lower Manhattan, the New York City Department of Health (NYCDOH) immediately activated its emergency response protocol, including the mobilization of an Emergency Operations Center. Surveillance, clinical, environmental, sheltering, laboratory, management information systems, and operations were among the preestablished emergency committees. Because of its proximity to the WTC site, an emergency clinic was established at NYCDOH for triage and treatment of injured persons. NYCDOH focused its initial efforts on assessing the public health and medical impact of the attack and the resources needed to respond to it such as the care and management of large numbers of persons injured or killed by the crash; subsequent fire and building collapse; the health and safety of rescue workers; the environmental health risks (e.g., asbestos, smoke, dust, or chemical inhalation); other illnesses related to the disruption of the physical infrastructure (e.g., waterborne and foodborne diseases); and mental health concerns. Despite the evacuation and relocation of NYCDOH's headquarters, the department continued essential public health services, including death registration.

Debris avalanches and slumps on the margins of volcanic domes on Venus: Characteristics of deposits

NASA Technical Reports Server (NTRS)

Bulmer, M. H.; Guest, J. E.; Beretan, K.; Michaels, Gregory A.; Saunders, R. Stephen

1992-01-01

Modified volcanic domes, referred to as collapsed margin domes, have diameters greater than those of terrestrial domes and were therefore thought to have no suitable terrestrial analogue. Comparison of the collapsed debris using the Magellan SAR images with volcanic debris avalanches on Earth has revealed morphological similarities. Some volcanic features identified on the seafloor from sonar images have diameters similar to those on Venus and also display scalloped margins, indicating modification by collapse. Examination of the SAR images of collapsed dome features reveals a number of distinct morphologies to the collapsed masses. Ten examples of collapsed margin domes displaying a range of differing morphologies and collapsed masses have been selected and examined.

Earthquakes as collapse precursors at the Han-sur-Lesse Cave in the Belgian Ardennes

NASA Astrophysics Data System (ADS)

Camelbeeck, Thierry; Quinif, Yves; Verheyden, Sophie; Vanneste, Kris; Knuts, Elisabeth

2018-05-01

Collapse activation is an ongoing process in the evolution of karstic networks related to the weakening of cave vaults. Because collapses are infrequent, few have been directly observed, making it challenging to evaluate the role of external processes in their initiation and triggering. Here, we study the two most recent collapses in the Dôme chamber of the Han-sur-Lesse Cave (Belgian Ardenne) that occurred on or shortly after 3rd December 1828 and between the 13th and 14th of March 1984. Because of the low probability that the two earthquakes that generated the strongest ground motions in Han-sur-Lesse since 1800, on 23rd February 1828 (Mw = 5.1 in Central Belgium) and 8th November 1983 (Mw = 4.8 in Liège) occurred by coincidence less than one year before these collapses, we suggest that the collapses are related to these earthquakes. We argue that the earthquakes accelerated the cave vault instability, leading to the collapses by the action of other factors weakening the host rock. In particular, the 1828 collapse was likely triggered by a smaller Mw = 4.2 nearby earthquake. The 1984 collapse followed two months of heavy rainfall that would have increased water infiltration and pressure in the rock mass favoring destabilization of the cave ceiling. Lamina counting of a stalagmite growing on the 1828 debris dates the collapse at 1826 ± 9 CE, demonstrating the possibility of dating previous collapses with a few years of uncertainty. Furthermore, our study opens new perspectives for studying collapses and their chronology both in the Han-sur-Lesse Cave and in other karstic networks. We suggest that earthquake activity could play a stronger role than previously thought in initiating cave collapses.

Real-world and trial-based cost-effectiveness analysis of bevacizumab in HER2-negative metastatic breast cancer patients: a study of the Southeast Netherlands Breast Cancer Consortium.

PubMed

van Kampen, R J W; Ramaekers, B L T; Lobbezoo, D J A; de Boer, M; Dercksen, M W; van den Berkmortel, F; Smilde, T J; van de Wouw, A J; Peters, F P J; van Riel, J M G; Peters, N A J B; Tjan-Heijnen, V C G; Joore, M A

2017-07-01

The aim of our analysis was to assess the real-world cost-effectiveness of bevacizumab in addition to taxane treatment versus taxane monotherapy for HER2-negative metastatic breast cancer compared with the cost-effectiveness based on the efficacy results from a trial. A state transition model was built to estimate costs, life years (LYs) and quality-adjusted life years (QALYs) for both treatments. Two scenarios were examined: a real-world scenario and a trial-based scenario in which transition probabilities were primarily based on a real-world cohort study and the E2100 trial, respectively. In both scenarios, costs and utility parameter estimates were extracted from the real-world cohort study. Moreover, the Dutch health care perspective was adopted. In both the real-world and trial scenarios, bevacizumab-taxane is more expensive (incremental costs of €56,213 and €52,750, respectively) and more effective (incremental QALYs of 0.362 and 0.189, respectively) than taxane monotherapy. In the real-world scenario, bevacizumab-taxane compared to taxane monotherapy led to an incremental cost-effectiveness ratio (ICER) of €155,261 per QALY gained. In the trial scenario, the ICER amounted to €278,711 per QALY gained. According to the Dutch informal threshold, bevacizumab in addition to taxane treatment was not considered cost-effective for HER2-negative metastatic breast cancer both in a real-world and in a trial scenario. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultrastructure of Lymphocystis Virus

PubMed Central

Zwillenberg, Lutz O.; Wolf, Ken

1968-01-01

Lymphocystis virus obtained from bluegills (Lepomis macrochirus) was cultured in the permanent bluegill cell line BF-2 and examined by electron microscopy in ultrathin sections of cell cultures and in negative-contrast preparations from cells and from centrifuged culture medium. According to negative-contrast preparations, the icosahedral virions have an overall diameter close to but not exceeding 300 mμ. Delicate filaments seem to issue from the vertices. In collapsed virions, an ordered array of morphological units was seen. Positively contrasted virions in ultrathin sections show a shell with three dark (heavy metal-stained) layers alternating with and separated by two clear layers. The acquisition of an additional outer membrane during release from the cell, as found in African swine fever virus, was never seen. Morphologically, lymphocystis virus is considered to be closely related to Tipula iridescent virus. Images PMID:4986903

The timing and intensity of column collapse during explosive volcanic eruptions

NASA Astrophysics Data System (ADS)

Carazzo, Guillaume; Kaminski, Edouard; Tait, Stephen

2015-02-01

Volcanic columns produced by explosive eruptions commonly reach, at some stage, a collapse regime with associated pyroclastic density currents propagating on the ground. The threshold conditions for the entrance into this regime are mainly controlled by the mass flux and exsolved gas content at the source. However, column collapse is often partial and the controls on the fraction of total mass flux that feeds the pyroclastic density currents, defined here as the intensity of collapse, are unknown. To better understand this regime, we use a new experimental apparatus reproducing at laboratory scale the convecting and collapsing behavior of hot particle-laden air jets. We validate the predictions of a 1D theoretical model for the entrance into the regime of partial collapse. Furthermore, we show that where a buoyant plume and a collapsing fountain coexist, the intensity of collapse can be predicted by a universal scaling relationship. We find that the intensity of collapse in the partial collapse regime is controlled by magma gas content and temperature, and always exceeds 40%, independent of peak mass flux and total erupted volume. The comparison between our theoretical predictions and a set of geological data on historic and pre-historic explosive eruptions shows that the model can be used to predict both the onset and intensity of column collapse, hence it can be used for rapid assessment of volcanic hazards notably ash dispersal during eruptive crises.

Heating- and pressure-induced transformations in amorphous and hexagonal ice: A computer simulation study using the TIP4P/2005 model

NASA Astrophysics Data System (ADS)

Engstler, Justin; Giovambattista, Nicolas

2017-08-01

We characterize the phase behavior of glassy water by performing extensive out-of-equilibrium molecular dynamics simulations using the TIP4P/2005 water model. Specifically, we study (i) the pressure-induced transformations between low-density (LDA) and high-density amorphous ice (HDA), (ii) the pressure-induced amorphization (PIA) of hexagonal ice (Ih), (iii) the heating-induced LDA-to-HDA transformation at high pressures, (iv) the heating-induced HDA-to-LDA transformation at low and negative pressures, (v) the glass transition temperatures of LDA and HDA as a function of pressure, and (vi) the limit of stability of LDA upon isobaric heating and isothermal decompression (at negative pressures). These transformations are studied systematically, over a wide range of temperatures and pressures, allowing us to construct a P-T phase diagram for glassy TIP4P/2005 water. Our results are in qualitative agreement with experimental observations and with the P-T phase diagram obtained for glassy ST2 water that exhibits a liquid-liquid phase transition and critical point. We also discuss the mechanism for PIA of ice Ih and show that this is a two-step process where first, the hydrogen-bond network (HBN) is distorted and then the HBN abruptly collapses. Remarkably, the collapse of the HB in ice Ih occurs when the average molecular orientations order, a measure of the tetrahedrality of the HBN, is of the same order as in LDA, suggesting a common mechanism for the LDA-to-HDA and Ih-to-HDA transformations.

Heating- and pressure-induced transformations in amorphous and hexagonal ice: A computer simulation study using the TIP4P/2005 model.

PubMed

Engstler, Justin; Giovambattista, Nicolas

2017-08-21

We characterize the phase behavior of glassy water by performing extensive out-of-equilibrium molecular dynamics simulations using the TIP4P/2005 water model. Specifically, we study (i) the pressure-induced transformations between low-density (LDA) and high-density amorphous ice (HDA), (ii) the pressure-induced amorphization (PIA) of hexagonal ice (I h ), (iii) the heating-induced LDA-to-HDA transformation at high pressures, (iv) the heating-induced HDA-to-LDA transformation at low and negative pressures, (v) the glass transition temperatures of LDA and HDA as a function of pressure, and (vi) the limit of stability of LDA upon isobaric heating and isothermal decompression (at negative pressures). These transformations are studied systematically, over a wide range of temperatures and pressures, allowing us to construct a P-T phase diagram for glassy TIP4P/2005 water. Our results are in qualitative agreement with experimental observations and with the P-T phase diagram obtained for glassy ST2 water that exhibits a liquid-liquid phase transition and critical point. We also discuss the mechanism for PIA of ice I h and show that this is a two-step process where first, the hydrogen-bond network (HBN) is distorted and then the HBN abruptly collapses. Remarkably, the collapse of the HB in ice I h occurs when the average molecular orientations order, a measure of the tetrahedrality of the HBN, is of the same order as in LDA, suggesting a common mechanism for the LDA-to-HDA and I h -to-HDA transformations.

Wave-Wave Coupling and Disasters: The 1985 Mexico Earthquake and the 2001 WTC Collapse

NASA Astrophysics Data System (ADS)

Lomnitz, C.

2002-12-01

Wave-wave coupling occurs in the presence of weak nonlinearity. It can generate quite dramatic, unexpected effects. In the 1985 earthquake disaster in Mexico City more than 400 high-rise buildings collapsed on soft ground with a loss of life of around 10,000. The emergence of a large, monochromatic, coherent ground wave was an unforeseen factor. Linear modeling failed to reproduce the main features of this signal including the prominent spectral peak close to the resonant frequency of the high-rise buildings, and an extremely long time duration (more than five minutes). The signal was apparently due to coupling of a fundamental Rayleigh mode to the quarter-wavelength shear resonance in the surface mud layer through their common frequency at 0.4 Hz. An additional unexpected feature was the low attenuation of these modes in the mud layer, and the presence of prograde particle motion. Prograde rotation, though not necessarily caused by nonlinear effects, will couple with structural modes of vibration that tend to destabilize a tall building, much like a tall ship in ocean waves. Such unanticipated features may play a critical role in earthquake disasters on soft ground. A related case is the World Trade Center disaster of 11 September 2001, which was presumed to be due to gradual heat softening of steel girders. If so, the Twin Towers should have leaned over sideways but actually the collapse occurred vertically and quite suddenly. A likely alternative is coupling between a fireball caused by a phase transition between low- and high-oxygen consumption modes in burning jet fuel: (low-oxygen) 2CnH2n+2 + (n+1)O2 = nC2 + (2n+2)H2O, (1) (high-oxygen) 2CnH2n+2 + (3n+1)O2 = 2nCO2 + (2n+2)H2O, (2) and a pressure pulse propagating vertically inside the tubular structure. The pulse would have taken out the concrete floors, thus initiating collapse by implosion of the structural shell. Linear thinking may fail to anticipate coupling, and thus appropriate preventive measures may not be provided.

Exploring the links between volcano flank collapse and magma evolution: Fogo oceanic shield volcano, Cape Verde

NASA Astrophysics Data System (ADS)

Cornu, Melodie-Neige; Paris, Raphael; Doucelance, Regis; Bachelery, Patrick; Guillou, Hervé

2017-04-01

Mass wasting of oceanic shield volcanoes is largely documented through the recognition of collapse scars and submarine debris fans. However, it is actually difficult to infer the mechanisms controlling volcano flank failures that potentially imply tens to hundreds of km3. Studies coupling detailed petrological and geochemical analyses of eruptive products hold clues for better understanding the relationships between magma sources, the plumbing system, and flank instability. Our study aims at tracking potential variations of magma source, storage and transport beneath Fogo shield volcano (Cape Verde) before and after its major flank collapse. We also provide a geochronological framework of this magmatic evolution through new radiometric ages (K-Ar and Ar-Ar) of both pre-collapse and post-collapse lavas. The central part of Fogo volcanic edifice is truncated by an 8 km-wide caldera opened to the East, corresponding to the scar of the last flank collapse (Monte Amarelo collapse, Late Pleistocene, 150 km3). Lavas sampled at the base of the scar (the so-called Bordeira) yielded ages between 158 and 136 ka. The age of the collapse is constrained between 68 ka (youngest lava flow cut by the collapse scar) and 59 ka (oldest lava flow overlapping the scar). The collapse walls display a complex structural, intrusive and eruptive history. Undersaturated volcanism (SiO2<43%) is surprisingly dominated by explosive products such as ignimbrites, with 4 major explosive episodes representing half of the volume of the central edifice. This explosive record onshore is correlated with the offshore record of mafic tephra and turbidites (Eisele et al., 2015). Major elements analyses indicate that the pre-collapse lavas are significantly less differentiated than post-collapse lavas, with a peak of alkalis at the collapse. Rare-earth elements concentration decreases with time, with a notable positive anomaly before the collapse. The evolution of the isotopic ratios (Sr, Nd and Pb) through time displays unusual V-shaped profiles centered around the collapse. The occurrence of the Monte Amarelo collapse is thus not disconnected from the magmatic evolution, both at the crustal and mantellic levels. Our results also point out the importance and relative frequency of explosive eruptions of undersaturated magmas at Fogo volcano.

Modelling shoal margin collapses and their morphodynamic effect on channels and shoals in a sandy estuary

NASA Astrophysics Data System (ADS)

van Dijk, W. M.; Mastbergen, D. R.; Van der Werf, J. J.; Leuven, J.; Kleinhans, M. G.

2017-12-01

Channel bank failure and collapses of shoal margins due to flow slides have been recorded in Dutch estuaries for the past 200 years. The effects of these collapses on the morphodynamics of estuaries are unknown, but could potentially increase the dynamics of channel-shoal interactions by causing perturbations of up to a million cubic meters per event, which could impact habitats and navigability. The processes of shoal margin collapses are currently not included in numerical morphodynamic models. The objectives of this study are to investigate where shoal margins collapses typically occur, what their dimensions are, and to model how shoal margin collapses affect the morphodynamics at the channel-shoal scale. We identified 300 shoal margin collapses from bathymetry data of the Western Scheldt estuary for the period 1959-2015, and found that the shape of a shoal margin collapse is well represented by 1/3 of an ellipsoid, and that its volume has a log-normal distribution with an average of 100,000 m3. We implemented a parameterization for shoal margin collapses and tested their effects on morphodynamics in a Delft3D numerical model schematization of the Western Scheldt estuary. Three sets of scenarios were analyzed for near-field morphodynamics and far-field effects on flow pattern and channel-bar morphology: 1) an observed single shoal margin collapse of 2014, 2) collapses on various locations that are susceptible to collapses, and 3) our novel stochastic model producing collapses over a time span of a decade. Results show that single shoal margin collapses only affect the local dynamics in longitudinal direction and dampen out within a year when the collapse is small. When larger disturbances reach the seaward or landward sill at tidal channel junctions over a longer time span, the bed elevation at the sill increases on average and decrease the hydraulic geometry of the channel junctions. The extent of far-field effects is sensitive to the grain-size of the deposit, where finer sediments are transported further away. The location of the deposit across the channel matters for disturbing the region around the collapse, where sediment transport is highest for the strongest residual current. These results imply that disturbances caused by dredging and dumping may likewise affect the dynamics of channel junctions.

Collapsing cavities in reactive and nonreactive media

NASA Astrophysics Data System (ADS)

Bourne, Neil K.; Field, John E.

1991-04-01

This paper presents results of a high-speed photographic study of cavities collapsed asymmetrically by shocks of strengths in the range 0.26 GPa to 3.5 GPa. Two-dimensional collapses of cavity configurations punched into a 12% by weight gelatine in water sheet, and an ammonium nitrate/sodium nitrate (AN/SN) emulsion explosive were photographed using schlieren optics. The single cavity collapses were characterized by the velocity of the liquid jet formed by the upstream wall as it was accelerated by the shock and by the time taken for the cavity to collapse. The shock pressure did not qualitatively affect the collapse behaviour but jet velocities were found to exceed incident shock velocities at higher pressures. The more violent collapses induced light emission from the compressed gas in the cavity. When an array of cavities collapsed, a wave, characterized by the particle velocity in the medium, the cavity diameter and the inter-cavity spacing, was found to run through the array. When such an array was created within an emulsion explosive, ignition of the reactive matrix occurred ahead of the collapse wave when the incident shock was strong.

Limacina retroversa's response to combined effects of ocean acidification and sea water freshening

NASA Astrophysics Data System (ADS)

Manno, C.; Morata, N.; Primicerio, R.

2012-11-01

Anthropogenic carbon dioxide emissions induce ocean acidification, thereby reducing carbonate ion concentration, which may affect the ability of calcifying organisms to build shells. Pteropods, the main planktonic producers of aragonite in the worlds' oceans, may be particularly vulnerable to changes in sea water chemistry. The negative effects are expected to be most severe at high-latitudes, where natural carbonate ion concentrations are low. In this study we investigated the combined effects of ocean acidification and freshening on Limacina retroversa, the dominant pteropod in sub polar areas. Living L. retroversa, collected in Northern Norwegian Sea, were exposed to four different pH values ranging from the pre-industrial level to the forecasted end of century ocean acidification scenario. Since over the past half-century the Norwegian Sea has experienced a progressive freshening with time, each pH level was combined with a salinity gradient in two factorial, randomized experiments investigating shell degradation, swimming behavior and survival. In addition, to investigate shell degradation without any physiologic influence, one perturbation experiments using only shells of dead pteropods was performed. Lower pH reduced shell mass whereas shell dissolution increased with pCO2. Interestingly, shells of dead organisms had a higher degree of dissolution than shells of living individuals. Mortality of Limacina retroversa was strongly affected only when both pH and salinity reduced simultaneously. The combined effects of lower salinity and lower pH also affected negatively the ability of pteropods to swim upwards. Results suggest that the energy cost of maintaining ion balance and avoiding sinking (in low salinity scenario) combined with the extra energy cost necessary to counteract shell dissolution (in high pCO2 scenario), exceed the available energy budget of this organism causing the pteropods to change swimming behavior and begin to collapse. Since L. retroversa play an important role in the transport of carbonates to the deep oceans these findings have significant implications for the mechanisms influencing the inorganic carbon cycle in the sub-polar area.

KSC-2012-4933

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel salute as the American flag is raised during the 9/11 memorial dedication ceremony. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4922

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel stand at attention as Kennedy Director Robert Cabana, at right, participates in a 9/11 memorial dedication at Fire Station 1. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4928

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel salute or stand at attention during a flag folding ceremony at the 9/11 memorial dedication ceremony. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4923

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel stand at attention as Kennedy Director Robert Cabana, at right, participates in a 9/11 memorial dedication at Fire Station 1. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4936

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, a horseless carriage in memory of firefighters lost on 9/11 is on display during the 9/11 memorial dedication ceremony. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4930

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel salute as the American flag is raised during the 9/11 memorial dedication ceremony. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4925

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel stand at attention as Kennedy Director Robert Cabana participates in a 9/11 memorial dedication at Fire Station 1. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4934

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel salute or stand at attention as the American flag is raised during the 9/11 memorial dedication ceremony. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4924

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel stand at attention as Kennedy Director Robert Cabana, at right, participates in a 9/11 memorial dedication at Fire Station 1. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4932

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, Fire and Rescue personnel salute as the American flag is raised during the 9/11 memorial dedication ceremony. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

KSC-2012-4926

NASA Image and Video Library

2012-09-11

CAPE CANAVERAL, Fla. – At Fire Station 1 at NASA’s Kennedy Space Center in Florida, a new 9/11 memorial was dedicated during a ceremony held by Kennedy’s Fire and Rescue personnel. Kennedy Fire and Rescue Services commemorated the 11th anniversary of 9/11 with a ceremony that included a minute of silence at 10:28 a.m., which was the moment of collapse of the north tower of the World Trade Center. Kennedy center-wide emergency units dispatched by Fire Control engaged in one-minute sirens, the new memorial was dedicated and the Honor Guard performed a flag-folding ceremony. Photo credit: NASA/Dimitri Gerondidakis

Numerical simulations of non-spherical bubble collapse.

PubMed

Johnsen, Eric; Colonius, Tim

2009-06-01

A high-order accurate shock- and interface-capturing scheme is used to simulate the collapse of a gas bubble in water. In order to better understand the damage caused by collapsing bubbles, the dynamics of the shock-induced and Rayleigh collapse of a bubble near a planar rigid surface and in a free field are analysed. Collapse times, bubble displacements, interfacial velocities and surface pressures are quantified as a function of the pressure ratio driving the collapse and of the initial bubble stand-off distance from the wall; these quantities are compared to the available theory and experiments and show good agreement with the data for both the bubble dynamics and the propagation of the shock emitted upon the collapse. Non-spherical collapse involves the formation of a re-entrant jet directed towards the wall or in the direction of propagation of the incoming shock. In shock-induced collapse, very high jet velocities can be achieved, and the finite time for shock propagation through the bubble may be non-negligible compared to the collapse time for the pressure ratios of interest. Several types of shock waves are generated during the collapse, including precursor and water-hammer shocks that arise from the re-entrant jet formation and its impact upon the distal side of the bubble, respectively. The water-hammer shock can generate very high pressures on the wall, far exceeding those from the incident shock. The potential damage to the neighbouring surface is quantified by measuring the wall pressure. The range of stand-off distances and the surface area for which amplification of the incident shock due to bubble collapse occurs is determined.

Numerical simulations of non-spherical bubble collapse

PubMed Central

JOHNSEN, ERIC; COLONIUS, TIM

2009-01-01

A high-order accurate shock- and interface-capturing scheme is used to simulate the collapse of a gas bubble in water. In order to better understand the damage caused by collapsing bubbles, the dynamics of the shock-induced and Rayleigh collapse of a bubble near a planar rigid surface and in a free field are analysed. Collapse times, bubble displacements, interfacial velocities and surface pressures are quantified as a function of the pressure ratio driving the collapse and of the initial bubble stand-off distance from the wall; these quantities are compared to the available theory and experiments and show good agreement with the data for both the bubble dynamics and the propagation of the shock emitted upon the collapse. Non-spherical collapse involves the formation of a re-entrant jet directed towards the wall or in the direction of propagation of the incoming shock. In shock-induced collapse, very high jet velocities can be achieved, and the finite time for shock propagation through the bubble may be non-negligible compared to the collapse time for the pressure ratios of interest. Several types of shock waves are generated during the collapse, including precursor and water-hammer shocks that arise from the re-entrant jet formation and its impact upon the distal side of the bubble, respectively. The water-hammer shock can generate very high pressures on the wall, far exceeding those from the incident shock. The potential damage to the neighbouring surface is quantified by measuring the wall pressure. The range of stand-off distances and the surface area for which amplification of the incident shock due to bubble collapse occurs is determined. PMID:19756233

A path model investigation of neurocognition, theory of mind, social competence, negative symptoms and real-world functioning in schizophrenia.

PubMed

Couture, Shannon M; Granholm, Eric L; Fish, Scott C

2011-02-01

Problems in real-world functioning are pervasive in schizophrenia and much recent effort has been devoted to uncovering factors which contribute to poor functioning. The goal of this study was to examine the role of four such factors: social cognition (theory of mind), neurocognition, negative symptoms, and functional capacity (social competence). 178 individuals with schizophrenia or schizoaffective disorder completed measures of theory of mind, neurocognition, negative symptoms, social competence, and self-reported functioning. Path models sought to determine the relationships among these variables. Theory of mind as indexed by the Hinting Task partially mediated the relationship between neurocognition and social competence, and negative symptoms and social competence demonstrated significant direct paths with self-reported functioning. Study results suggest theory of mind serves as an important mediator in addition to previously investigated social cognitive domains of emotional and social perception. The current study also highlights the need to determine variables which mediate the relationship between functional capacity and real-world functioning. Copyright © 2010 Elsevier B.V. All rights reserved.

A Simple Model for Human and Nature Interaction

NASA Astrophysics Data System (ADS)

Motesharrei, S.; Rivas, J.; Kalnay, E.

2012-12-01

There are widespread concerns that current trends in population and resource-use are unsustainable, but the possibilities of an overshoot and collapse remain unclear and controversial. Collapses of civilizations have occurred many times in the past 5000 years, often followed by centuries of economic, intellectual, and population decline. Many different natural and social phenomena have been invoked to explain specific collapses, but a general explanation remains elusive. Two important features seem to appear across societies that have collapsed: Ecological Strain and Economic Stratification. Our new model (Human And Nature DYnamics, HANDY) has just four equations that describe the evolution of Elites, Commoners, Nature, and Wealth. Mechanisms leading to collapse are discussed and the measure "Carrying Capacity" is developed and defined. The model shows that societal collapse can happen due to either one of two independent factors: (1) over-consumption of natural resources, and/or (2) deep inequity between Elites and Commoners. The model also portrays two distinct types of collapse: (i) collapse followed by recovery of nature, and (ii) full collapse. The model suggests that the estimation of Carrying Capacity is a practical means for early detection of a collapse. Collapse can be avoided, and population can reach a sustainable equilibrium, if the rate of depletion of nature is reduced to a sustainable level, and if resources are distributed in a reasonably equitable fashion.; A type-ii (full) collapse is shown in this figure. With high inequality and high depletion, societies are doomed to collapse. Wealth starts to decrease when population rises above the carrying capacity. The large gap between carrying capacity and its maximum is a result of depletion factor being much larger than the sustainable limit. ; It is possible to overshoot, oscillate, and eventually converge to an equilibrium, even in an inequitable society. However, it requires policies that control birth rates and inequality. Additionally, depletion (production) must be kept within a reasonable range.

Volcano collapse promoted by progressive strength reduction: New data from Mount St. Helens

USGS Publications Warehouse

Reid, Mark E.; Keith, Terry E.C.; Kayen, Robert E.; Iverson, Neal R.; Iverson, Richard M.; Brien, Dianne

2010-01-01

Rock shear strength plays a fundamental role in volcano flank collapse, yet pertinent data from modern collapse surfaces are rare. Using samples collected from the inferred failure surface of the massive 1980 collapse of Mount St. Helens (MSH), we determined rock shear strength via laboratory tests designed to mimic conditions in the pre-collapse edifice. We observed that the 1980 failure shear surfaces formed primarily in pervasively shattered older dome rocks; failure was not localized in sloping volcanic strata or in weak, hydrothermally altered rocks. Our test results show that rock shear strength under large confining stresses is reduced ∼20% as a result of large quasi-static shear strain, as preceded the 1980 collapse of MSH. Using quasi-3D slope-stability modeling, we demonstrate that this mechanical weakening could have provoked edifice collapse, even in the absence of transiently elevated pore-fluid pressures or earthquake ground shaking. Progressive strength reduction could promote collapses at other volcanic edifices.

Mortality among World Trade Center Rescue and Recovery Workers, 2002 – 2011

PubMed Central

Stein, Cheryl R; Wallenstein, Sylvan; Shapiro, Moshe; Hashim, Dana; Moline, Jacqueline M; Udasin, Iris; Crane, Michael A; Luft, Benjamin J; Lucchini, Roberto G; Holden, William L

2015-01-01

Background Rescue and recovery workers responding to the 2001 collapse of the World Trade Center (WTC) sustained exposures to toxic chemicals and have elevated rates of multiple morbidities. Methods Using data from the World Trade Center Health Program and the National Death Index for 2002 – 2011, we examined standardized mortality ratios (SMR) and proportional cancer mortality ratios (PCMR) with indirect standardization for age, sex, race, and calendar year to the U.S. general population, as well as associations between WTC-related environmental exposures and all-cause mortality. Results We identified 330 deaths among 28,918 responders (SMR 0.43, 95% CI 0.39 – 0.48). No cause-specific SMRs were meaningfully elevated. PCMRs were elevated for neoplasms of lymphatic and hematopoietic tissue (PCMR 1.76, 95% CI 1.06 – 2.75). Mortality hazard ratios showed no linear trend with exposure. Conclusions Consistent with a healthy worker effect, all-cause mortality among responders was not elevated. There was no clear association between intensity and duration of exposure and mortality. Surveillance is needed to monitor the proportionally higher cancer mortality attributed to lymphatic/hematopoietic neoplasms. PMID:26727695

From Space Archeology to Serving the World Today: A 20-Year Journey from the Jungles of Guatemala to a Network of Satellite Remote Sensing Facilities Around the World

NASA Astrophysics Data System (ADS)

Irwin, Daniel

2016-06-01

Earth observing satellites provide a 21st century capability to detect unrecorded archeological sites that are often invisible to the naked eye. This information can be used to understand issues in human settlement, environmental interaction, and the impact of climate change to past cultures. Archeologists want to know how ancient people successfully adapted to their environment and what factors may have led to their collapse or disappearance. Some cultures overextended the capacity of their landscape, causing destructive environmental effects which led to their demise. To avoid repeating mistakes of the past and adapt to challenges today, NASA and the US Agency for International Development (USAID)-- in partnership with leading regional organizations around the world--have implemented SERVIR. SERVIR is a joint development initiative to help countries use information provided by Earth observing satellites and geospatial technologies for managing climate risks and land use. SERVIR is improving awareness, increasing access to information, and supporting analysis to help people in Africa, Hindu Kush-Himalaya, Lower Mekong, and Mesoamerica manage challenges in the areas of food security, water resources, land use change, and natural disasters.

On the Organisation of World Ships and Other Gigascale Interstellar Space Exploration Projects

NASA Astrophysics Data System (ADS)

Ceyssens, F.; Driesen, M.; Wouters, K.

The development and deployment of world ships or other feats of interstellar exploration will without doubt require orders of magnitude more resources than needed for current or past megaprojects (Apollo, Iter, LHC,...). Question is how enough resources for such gigaprojects can be found in a scenario assuming limited, moderate economic growth throughout the next centuries, i.e. without human population and productivity continuing to grow exponentially, and without extreme events such as economic collapse or singularity.Three defining features of gigascale space projects are identified, which should be recognized to the fullest: their almost absolute nonprofit character, their massive cost in terms of time and resources and their non-urgency leading to procrastina- tion. It will be argued that the best chance of getting a world ship or another interstellar project started in this generation is to establish an international network of non governmental organizations (NGOs) focused on private and public fundraising for interstellar exploration and supporting a bottom-up societal movement, similar to e.g. the WWF. It will be shown that this path can reduce the massive barriers to entry as well as the level of governmental support needed.

Historical time-recessive recombinant nucleotidal gene transfer

NASA Astrophysics Data System (ADS)

Norton, Michael A.

2013-10-01

Whether conscious of it or not, physicist Tim Berners-Lee basically applied principle of a nuclear chain reaction to electron transport, a remarkable outcome being the world wide web. On a less dense exponential than the nucleus, but still by out of control design (1999), the flow of electrons with high symmetry (hypertext) brought about astonishing new insights to the field. No one in the author's sphere of influence, including the author, ever learned or taught that such chain reactions have a time-recessive trajectory, such that key significant moments in the new science had impact not only the world at present, but on scale overlapping with ancestors. Dr. Chuck Darwin learned man indeed did arise in Africa (brown toastmasters); author suggests his creed ``survival of the fittest'' in post-20th century hindsight, for man initialized nuclear energy in Eurasia (white toastmasters), and nearly brought the world to collapse by dropping nuclear weapons on humans in Asia (yellow toastmasters), be best updated ``survival of the most communicative.'' If true, this informs that the measure of the appended science's power is as equally as important as the measure of its speed, ergo, there really is no energy crisis.

Investigating collapse structures in oceanic islands using magnetotelluric surveys: The case of Fogo Island in Cape Verde

NASA Astrophysics Data System (ADS)

Martínez-Moreno, F. J.; Monteiro Santos, F. A.; Madeira, J.; Pous, J.; Bernardo, I.; Soares, A.; Esteves, M.; Adão, F.; Ribeiro, J.; Mata, J.; Brum da Silveira, A.

2018-05-01

One of the most remarkable natural events on Earth are the large lateral flank collapses of oceanic volcanoes, involving volumes of rock exceeding tens of km3. These collapses are relatively frequent in recent geological times as supported by evidence found in the geomorphology of volcanic island edifices and associated debris flows deposited on the proximal ocean floor. The Island of Fogo in the Cape Verde archipelago is one of the most active and prominent oceanic volcanoes on Earth. The island has an average diameter of 25 km and reaches a maximum elevation of 2829 m above sea level (m a.s.l.) at Pico do Fogo, a young stratovolcano located within a summit depression open eastward due to a large lateral flank collapse. The sudden collapse of the eastern flank of Fogo Island produced a megatsunami 73 ky ago. The limits of the flank collapse were deduced as well from geomorphologic markers within the island. The headwall of the collapse scar is interpreted as either being located beneath the post-collapse volcanic infill of the summit depression or located further west, corresponding to the Bordeira wall that partially surrounds it. The magnetotelluric (MT) method provides a depth distribution of the ground resistivity obtained by the simultaneous measurement of the natural variations of the electric and magnetic field of the Earth. Two N-S magnetotelluric profiles were acquired across the collapsed area to determine its geometry and boundaries. The acquired MT data allowed the determination of the limits of the collapsed area more accurately as well as its morphology at depth and thickness of the post-collapse infill. According to the newly obtained MT data and the bathymetry of the eastern submarine flank of Fogo, the volume involved in the flank collapse is estimated in 110 km3. This volume -the first calculated onshore- stands between the previously published more conservative and excessive calculations -offshore- that were exclusively based in geomorphic evidence. The model for the summit depression proposing two caldera collapses preceding the collapse of the eastern flank of Fogo is supported by the MT data.

Metal matrix composites: History, status, factors and future

NASA Astrophysics Data System (ADS)

Cyriac, Ajith James

The history, status, and future of metal matrix composites are presented by evaluating the progression of available literature through time. The trends that existed and issues that still prevail are discussed and a prediction of the future for MMCs is presented. The factors that govern the performance of metal matrix composites are also discussed. In many developed countries and in several developing countries there exists continued interest in MMCs. Researchers tried numerous combinations of matrices and reinforcements since work strictly on MMCs began in the 1950s. This led to developments for aerospace and defense applications, but resultant commercial applications were limited. The introduction of ceramic whiskers as reinforcement and the development of 'in-situ' eutectics in the 1960s aided high temperature applications in aircraft engines. In the late 1970s the automobile industries started to take MMCs seriously. In the last 20 years, MMCs evolved from laboratories to a class of materials with numerous applications and commercial markets. After the collapse of the Berlin Wall, prevailing order in the world changed drastically. This effect was evident in the progression of metal matrix composites. The internet connected the world like never before and tremendous information was available for researchers around the world. Globalization and the internet resulted in the transformation of the world to a more level playing field, and this effect is evident in the nature and source of research on metal matrix composites happening around the world.

Global water dynamics: issues for the 21st century.

PubMed

Simonovic, Slobodan P

2002-01-01

The WorldWater system dynamics model has been developed for modeling the global world water balance and capturing the dynamic character of the main variables affecting water availability and use in the future. Despite not being a novel approach, system dynamics offers a new way of addressing complex systems. WorldWater simulations are clearly demonstrating the strong feedback relation between water availability and different aspects of world development. Results of numerous simulations are contradictory to the assumption made by many global modelers that water is not an issue on the global scale. Two major observations can be made from early simulations: (a) the use of clean water for dilution and transport of wastewater, if not dealt with in other ways, imposes a major stress on the global world water balance; and (b) water use by different sectors is demonstrating quite different dynamics than predicted by classical forecasting tools and other water-models. Inherent linkages between water quantity and quality sectors with food, industry, persistent pollution, technology, and non-renewable resources sectors of the model create shoot and collapse behavior in water use dynamics. This paper discusses a number of different water-related scenarios and their implications on the global water balance. In particular, two extreme scenarios (business as usual - named "Chaos", and unlimited desalination - named "Ocean") are presented in the paper. Based on the conclusions derived from these two extreme cases a set of more moderate and realistic scenarios (named "Conservation") is proposed and their consequences on the global water balance are evaluated.

Regular Numbers and Mathematical Worlds

ERIC Educational Resources Information Center

Whitacre, Ian; Bouhjar, Khalid; Bishop, Jessica Pierson; Philipp, Randolph; Schappelle, Bonnie P.

2016-01-01

Rather than describing the challenges of integer learning in terms of a transition from positive to negative numbers, we have arrived at a different perspective: We view students as inhabiting distinct mathematical worlds consisting of particular types of numbers (as construed by the students). These worlds distinguish and illuminate students'…

Collapse Causes Analysis and Numerical Simulation for a Rigid Frame Multiple Arch Bridge

NASA Astrophysics Data System (ADS)

Zuo, XinDai

2018-03-01

Following the collapse accident of Baihe Bridge, the author built a plane model of the whole bridge firstly and analyzed the carrying capacity of the structure for a 170-tons lorry load. Then the author built a spatial finite element model which can accurately simulate the bridge collapse course. The collapse course was simulated and the accident scene was reproduced. Spatial analysis showed rotational stiffness of the pier bottom had a large influence on the collapse from of the superstructures. The conclusion was that the170 tons lorry load and multiple arch bridge design were the important factors leading to collapse.

PREFACE: Collapse Calderas Workshop

NASA Astrophysics Data System (ADS)

Gottsmann, Jo; Aguirre-Diaz, Gerardo

2008-10-01

Caldera-formation is one of the most awe-inspiring and powerful displays of nature's force. Resultant deposits may cover vast areas and significantly alter the immediate topography. Post-collapse activity may include resurgence, unrest, intra-caldera volcanism and potentially the start of a new magmatic cycle, perhaps eventually leading to renewed collapse. Since volcanoes and their eruptions are the surface manifestation of magmatic processes, calderas provide key insights into the generation and evolution of large-volume silicic magma bodies in the Earth's crust. Despite their potentially ferocious nature, calderas play a crucial role in modern society's life. Collapse calderas host essential economic deposits and supply power for many via the exploitation of geothermal reservoirs, and thus receive considerable scientific, economic and industrial attention. Calderas also attract millions of visitors world-wide with their spectacular scenic displays. To build on the outcomes of the 2005 calderas workshop in Tenerife (Spain) and to assess the most recent advances on caldera research, a follow-up meeting was proposed to be held in Mexico in 2008. This abstract volume presents contributions to the 2nd Calderas Workshop held at Hotel Misión La Muralla, Querétaro, Mexico, 19-25 October 2008. The title of the workshop `Reconstructing the evolution of collapse calderas: Magma storage, mobilisation and eruption' set the theme for five days of presentations and discussions, both at the venue as well as during visits to the surrounding calderas of Amealco, Amazcala and Huichapan. The multi-disciplinary workshop was attended by more than 40 scientist from North, Central and South America, Europe, Australia and Asia. Contributions covered five thematic topics: geology, geochemistry/petrology, structural analysis/modelling, geophysics, and hazards. The workshop was generously supported by the International Association of Volcanology and the Chemistry of The Earth's Interior (IAVCEI), the International Union of Geodesy and Geophysics (IUGG), the Universidad Nacional Autónoma de México (UNAM) through the Coordinación de la Investigación Científica, the Institute of Physics Publishing services, the Consejo Nacional de Ciencia y Tecnología de Querétaro (CONCYTEQ). The workshop represented the key activity of the IAVCEI Commission on Collapse Calderas in 2008. We, the workshop organizers, would like to express our gratitude to all workshop participants, the staff of Misión La Muralla, the Centro de Geociencias of UNAM for administrative and logistic support, to Adelina Geyer for web support, to María Inés Rojano for organization of logistics, the Universidad Autónoma de San Luis Potosí for logistics support, the Comisiòn Nacional de Electricidad for authorizing a visit to Los Azufres geothermal field, and to all sponsors that provided financial support. We expect these proceedings to stimulate further fruitful discussions, which we hope will be continued at a future meeting. Jo Gottsmann and Gerardo Aguirre-Diaz October 2008

Centrifuge tests on simulation of the ''cookie cutter'' mechanism of chimney collapse into underground openings: Final report

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

Kutter, B.L.; Chang, Ging-Song

The underground testing of nuclear devices causes the formation of large underground cavities which eventually may be filled by rubble and soil falling from the roof of the cavity. The zone of collapsing soil progresses upward toward the ground surface to form a ''chimney.'' The mechanisms of chimney collapse are important to understand for two important reasons. (1) A devastating and sudden propagation of the collapse may result in the formation of a surface crater which may threaten personnel and equipment in the vicinity of the crater. (2) Different collapse patterns are known to occur in the field and somemore » of these collapse patterns are known to be associated with leakage of radioactive wastes to the ground surface. A number of centrifuge tests were conducted by Kutter et al. (1988), to study the collapse of cavities in uniform dry sands. In these materials, the chimney collapse patterns were found to involve continuous, smoothly varying shear strain patterns in the chimney. The pattern of collapse in one of the tests is shown in figure 1. Figure 1a shows the surface crater that formed on the ground surface due to the collapse of a 6 inch diameter cavity buried 18'' beneath the ground surface. This result was obtained by draining fluid out of a 6'' rubber bag while the centrifuge was spinning at 11 g.« less

Exploding and Imaging of Electron Bubbles in Liquid Helium

NASA Astrophysics Data System (ADS)

Yadav, Neha; Vadakkumbatt, Vaisakh; Maris, Humphrey J.; Ghosh, Ambarish

2017-06-01

An electron bubble in liquid helium-4 under the saturated vapor pressure becomes unstable and explodes if the pressure becomes more negative than -1.9 bars. In this paper, we use focused ultrasound to explode electron bubbles. We then image at 30,000 frames per second the growth and subsequent collapse of the bubbles. We find that bubbles can grow to as large as 1 mm in diameter within 2 ms after the cavitation event. We examine the relation between the maximum size of the bubble and the lifetime and find good agreement with the experimental results.

Not All Emotions Are Created Equal: The Negativity Bias in Social-Emotional Development

ERIC Educational Resources Information Center

Vaish, Amrisha; Grossman, Tobias; Woodward, Amanda

2008-01-01

There is ample empirical evidence for an asymmetry in the way that adults use positive versus negative information to make sense of their world; specifically, across an array of psychological situations and tasks, adults display a negativity bias, or the propensity to attend to, learn from, and use negative information far more than positive…

26 CFR 1.341-1 - Collapsible corporations; in general.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 26 Internal Revenue 4 2014-04-01 2014-04-01 false Collapsible corporations; in general. 1.341-1... TAX (CONTINUED) INCOME TAXES (CONTINUED) Collapsible Corporations; Foreign Personal Holding Companies § 1.341-1 Collapsible corporations; in general. Subject to the limitations contained in § 1.341-4 and...

26 CFR 1.341-1 - Collapsible corporations; in general.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 4 2010-04-01 2010-04-01 false Collapsible corporations; in general. 1.341-1... TAX (CONTINUED) INCOME TAXES Collapsible Corporations; Foreign Personal Holding Companies § 1.341-1 Collapsible corporations; in general. Subject to the limitations contained in § 1.341-4 and the exceptions...

26 CFR 1.341-1 - Collapsible corporations; in general.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 4 2013-04-01 2013-04-01 false Collapsible corporations; in general. 1.341-1... TAX (CONTINUED) INCOME TAXES (CONTINUED) Collapsible Corporations; Foreign Personal Holding Companies § 1.341-1 Collapsible corporations; in general. Subject to the limitations contained in § 1.341-4 and...

26 CFR 1.341-1 - Collapsible corporations; in general.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 4 2011-04-01 2011-04-01 false Collapsible corporations; in general. 1.341-1... TAX (CONTINUED) INCOME TAXES Collapsible Corporations; Foreign Personal Holding Companies § 1.341-1 Collapsible corporations; in general. Subject to the limitations contained in § 1.341-4 and the exceptions...

26 CFR 1.341-1 - Collapsible corporations; in general.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 4 2012-04-01 2012-04-01 false Collapsible corporations; in general. 1.341-1... TAX (CONTINUED) INCOME TAXES (Continued) Collapsible Corporations; Foreign Personal Holding Companies § 1.341-1 Collapsible corporations; in general. Subject to the limitations contained in § 1.341-4 and...

Lessons Learned from the University of Virginia's Balcony Collapse.

ERIC Educational Resources Information Center

Dillman, Robert P.; Klingel, Jay W.

2002-01-01

Discusses the 1997 collapse of a balcony on a historic building at the University of Virginia, which resulted in a death and several injuries. Explores the balcony structure and cause of the collapse, any possibly preventative measures, and the resolution of legal proceedings resulting from the collapse. (EV)

Coping Self-Efficacy Mediates the Effects of Negative Cognitions on Posttraumatic Distress

PubMed Central

Cieslak, Roman; Benight, Charles C.; Lehman, Victoria Caden

2008-01-01

Although cognitive distortions have predicted posttraumatic distress after various types of traumatic events, the mechanisms through which cognitive distortions influence posttraumatic distress remain unclear. We hypothesized that coping self-efficacy, the belief in one’s own ability to manage posttraumatic recovery demands, would operate as a mediator between negative cognitions (about self, about the world, and self-blame beliefs) and posttraumatic distress. In the cross-sectional Study 1, data collected among 66 adult female victims of child sexual abuse indicated that coping self-efficacy mediated the effects of negative cognitions about self and about the world on posttraumatic distress. The same pattern of results was found in a longitudinal Study 2, conducted among 70 survivors of motor vehicle accidents. Coping self-efficacy measured at 1 month after the trauma mediated the effects of 7-day negative cognitions about self and about the world on 3-month posttraumatic distress. In both studies self-blame was not related to posttraumatic distress and the effect of self-blame on posttraumatic distress was not mediated by coping self-efficacy. The results provide insight into a mechanism through which negative cognitions may affect posttraumatic distress and highlight the potential importance of interventions aimed at enhancing coping self-efficacy beliefs. PMID:18456241

On peaceful coexistence: is the collapse postulate incompatible with relativity?

NASA Astrophysics Data System (ADS)

Myrvold, Wayne C.

In this paper, it is argued that the prima facie conflict between special relativity and the quantum-mechanical collapse postulate is only apparent, and that the seemingly incompatible accounts of entangled systems undergoing collapse yielded by different reference frames can be regarded as no more than differing accounts of the same processes and events. Attention to the transformation properties of quantum-mechanical states undergoing unitary, non-collapse evolution points the way to a treatment of collapse evolution consistent with the demands of relativity.

Why do naked singularities form in gravitational collapse? II

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

Joshi, Pankaj S.; Goswami, Rituparno; Dadhich, Naresh

We examine physical features that could lead to formation of a naked singularity rather than black hole, as end state of spherical collapse. Generalizing earlier results on dust collapse to general type I matter fields, it is shown that collapse always creates black hole if shear vanishes or density is homogeneous. It follows that nonzero shear is a necessary condition for singularity to be visible to external observers, when trapped surface formation is delayed by shearing forces or inhomogeneity within the collapsing cloud.

The Mars imperative: Species survival and inspiring a globalized culture

NASA Astrophysics Data System (ADS)

Barker, Donald C.

2015-02-01

Humanity has crossed a unique technological threshold enabling self-guided survival, a first in the history of life on Earth. From a human perspective the Earth may be considered as a single interconnected ecosystem, and given our tenuous understanding and control over the environment as well as our own behaviors, ever-looming specters of social collapse or even extinction dictate enacting immediate off-world diversification and self-preservation efforts. Herein, Mars is touted as the most tenable and sustainable location in which to initiate such permanent diversification. Scientific curiosity alone cannot initiate nor drive such off-world settlement and concerted impetus and public support for such an endeavor is shown to be constrained by human attention span. Lastly, the initial act of settlement uniquely serves as humanities greatest globally inspiring self-initiated endeavor, a tangible benefit capable of inspiring generations, connecting cultures and motivating college enrollments and career path choices in science, technology, engineering and math (STEM) in a manner similar to the dawn of human space exploration.

Critical tipping point distinguishing two types of transitions in modular network structures

NASA Astrophysics Data System (ADS)

Shai, Saray; Kenett, Dror Y.; Kenett, Yoed N.; Faust, Miriam; Dobson, Simon; Havlin, Shlomo

2015-12-01

Modularity is a key organizing principle in real-world large-scale complex networks. The relatively sparse interactions between modules are critical to the functionality of the system and are often the first to fail. We model such failures as site percolation targeting interconnected nodes, those connecting between modules. We find, using percolation theory and simulations, that they lead to a "tipping point" between two distinct regimes. In one regime, removal of interconnected nodes fragments the modules internally and causes the system to collapse. In contrast, in the other regime, while only attacking a small fraction of nodes, the modules remain but become disconnected, breaking the entire system. We show that networks with broader degree distribution might be highly vulnerable to such attacks since only few nodes are needed to interconnect the modules, consequently putting the entire system at high risk. Our model has the potential to shed light on many real-world phenomena, and we briefly consider its implications on recent advances in the understanding of several neurocognitive processes and diseases.

Head and neck cancers associated with exposure to the September 11, 2001 World Trade Center terrorist attacks.

PubMed

Leeman, Jonathan E; McBride, Sean M; Spielsinger, Daniel; Sherman, Eric J; Wong, Richard; Riaz, Nadeem; Lee, Nancy Y; Tsai, Chiaojung Jillian

2018-06-15

Exposure at the World Trade Center (WTC) terrorist collapse site on September 11, 2001 has been associated with increased cancer risk, though observational studies have identified very few cases of head and neck cancer (HNC) in exposed individuals. Eighty seven patients were identified who presented to our institution with HNC diagnosed from 2002 to 2017 who reported WTC exposure. The annual number and proportion of WTC-exposed HNC patients has been steadily increasing since 2002, with most cancers developing >10 years following the event. Furthermore, WTC-exposed patients with human papillomavirus (HPV)-positive OPC experienced significantly inferior outcomes compared with non-WTC exposed patients with HPV+ OPC (disease free survival 80.1% vs. 65.6% at 4 years, p = 0.04). This single institution study cannot establish evidence of exposure-mediated causation but higher recurrence rates in the WTC-exposed HPV+ OPC population suggest a treatment refractory tumor biology and possible exposure synergism with HPV-mediated oncogenesis. © 2018 UICC.

Increased natural mortality at low abundance can generate an Allee effect in a marine fish.

PubMed

Kuparinen, Anna; Hutchings, Jeffrey A

2014-10-01

Negative density-dependent regulation of population dynamics promotes population growth at low abundance and is therefore vital for recovery following depletion. Inversely, any process that reduces the compensatory density-dependence of population growth can negatively affect recovery. Here, we show that increased adult mortality at low abundance can reverse compensatory population dynamics into its opposite-a demographic Allee effect. Northwest Atlantic cod (Gadus morhua) stocks collapsed dramatically in the early 1990s and have since shown little sign of recovery. Many experienced dramatic increases in natural mortality, ostensibly attributable in some populations to increased predation by seals. Our findings show that increased natural mortality of a magnitude observed for overfished cod stocks has been more than sufficient to fundamentally alter the dynamics of density-dependent population regulation. The demographic Allee effect generated by these changes can slow down or even impede the recovery of depleted populations even in the absence of fishing.

Rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) syndrome may have a hypothalamus-periaqueductal gray localization.

PubMed

Chow, Cristelle; Fortier, Marielle Valerie; Das, Lena; Menon, Anuradha P; Vasanwala, Rashida; Lam, Joyce C M; Ng, Zhi Min; Ling, Simon Robert; Chan, Derrick W S; Choong, Chew Thye; Liew, Wendy K M; Thomas, Terrence

2015-05-01

Anatomical localization of the rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) syndrome has proved elusive. Most patients had neuroimaging after cardiorespiratory collapse, revealing a range of ischemic lesions. A 15-year-old obese boy with an acute febrile encephalopathy had hypoventilation, autonomic dysfunction, visual hallucinations, hyperekplexia, and disordered body temperature, and saltwater regulation. These features describe the ROHHAD syndrome. Cerebrospinal fluid analysis showed pleocytosis, elevated neopterins, and oligoclonal bands, and serology for systemic and antineuronal antibodies was negative. He improved after receiving intravenous steroids, immunoglobulins, and long-term mycophenolate. Screening for neural crest tumors was negative. Magnetic resonance imaging of the brain early in his illness showed focal inflammation in the periaqueductal gray matter and hypothalamus. This unique localization explains almost all symptoms of this rare autoimmune encephalitis. Copyright © 2015 Elsevier Inc. All rights reserved.

A 110-ms pulsar, with negative period derivative, in the globular cluster M15

NASA Technical Reports Server (NTRS)

Wolszczan, A.; Kulkarni, S. R.; Middleditch, J.; Backer, D. C.; Fruchter, A. S.; Dewey, R. J.

1989-01-01

The discovery of a 110-ms pulsar, PSR2127+11, in the globular cluster M15, is reported. The results of nine months of timing measurements place the new pulsar about 2 arcsec from the center of the cluster, and indicate that it is not a member of a close binary system. The measured negative value of the period derivative is probably the result of the pulsar being bodily accelerated in our direction by the gravitational field of the collapsed core of M15. This apparently overwhelms a positive contribution to the period derivative due to magnetic braking. Although the pulsar has an unexpectedly long period, it is argued that it belongs to the class of 'recycled' pulsars, which have been spun up by accretion in a binary system. The subsequent loss of the pulsar's companion is probably due to disruption of the system by close encounters with other stars.

Origami-inspired, on-demand deployable and collapsible mechanical metamaterials with tunable stiffness

NASA Astrophysics Data System (ADS)

Zhai, Zirui; Wang, Yong; Jiang, Hanqing

2018-03-01

Origami has been employed to build deployable mechanical metamaterials through folding and unfolding along the crease lines. Deployable metamaterials are usually flexible, particularly along their deploying and collapsing directions, which unfortunately in many cases leads to an unstable deployed state, i.e., small perturbations may collapse the structure along the same deployment path. Here we create an origami-inspired mechanical metamaterial with on-demand deployability and selective collapsibility through energy analysis. This metamaterial has autonomous deployability from the collapsed state and can be selectively collapsed along two different paths, embodying low stiffness for one path and substantially high stiffness for another path. The created mechanical metamaterial yields load-bearing capability in the deployed direction while possessing great deployability and collapsibility. The principle in this work can be utilized to design and create versatile origami-inspired mechanical metamaterials that can find many applications.

Explosively driven hypervelocity launcher: Second-stage augmentation techniques

NASA Technical Reports Server (NTRS)

Baum, D. W.

1973-01-01

The results are described of a continuing study aimed at developing a two-stage explosively driven hypervelocity launcher capable of achieving projectile velocities between 15 and 20 km/sec. The testing and evaluation of a new cylindrical impact technique for collapsing the barrel of two-stage launcher are reported. Previous two-stage launchers have been limited in ultimate performance by incomplete barrel collapse behind the projectile. The cylindrical impact technique explosively collapses a steel tube concentric with and surrounding the barrel of the launcher. The impact of the tube on the barrel produces extremely high stresses which cause the barrel to collapse. The collapse rate can be adjusted by appropriate variation of the explosive charge and tubing parameters. Launcher experiments demonstrated that the technique did achieve complete barrel collapse and form a second-stage piston. However, jetting occurred in the barrel collapse process and was responsible for severe projectile damage.

Origami-inspired, on-demand deployable and collapsible mechanical metamaterials with tunable stiffness.

PubMed

Zhai, Zirui; Wang, Yong; Jiang, Hanqing

2018-02-27

Origami has been employed to build deployable mechanical metamaterials through folding and unfolding along the crease lines. Deployable metamaterials are usually flexible, particularly along their deploying and collapsing directions, which unfortunately in many cases leads to an unstable deployed state, i.e., small perturbations may collapse the structure along the same deployment path. Here we create an origami-inspired mechanical metamaterial with on-demand deployability and selective collapsibility through energy analysis. This metamaterial has autonomous deployability from the collapsed state and can be selectively collapsed along two different paths, embodying low stiffness for one path and substantially high stiffness for another path. The created mechanical metamaterial yields load-bearing capability in the deployed direction while possessing great deployability and collapsibility. The principle in this work can be utilized to design and create versatile origami-inspired mechanical metamaterials that can find many applications. Copyright © 2018 the Author(s). Published by PNAS.

Origami-inspired, on-demand deployable and collapsible mechanical metamaterials with tunable stiffness

PubMed Central

Zhai, Zirui; Wang, Yong

2018-01-01

Origami has been employed to build deployable mechanical metamaterials through folding and unfolding along the crease lines. Deployable metamaterials are usually flexible, particularly along their deploying and collapsing directions, which unfortunately in many cases leads to an unstable deployed state, i.e., small perturbations may collapse the structure along the same deployment path. Here we create an origami-inspired mechanical metamaterial with on-demand deployability and selective collapsibility through energy analysis. This metamaterial has autonomous deployability from the collapsed state and can be selectively collapsed along two different paths, embodying low stiffness for one path and substantially high stiffness for another path. The created mechanical metamaterial yields load-bearing capability in the deployed direction while possessing great deployability and collapsibility. The principle in this work can be utilized to design and create versatile origami-inspired mechanical metamaterials that can find many applications. PMID:29440441

Kinematic fingerprint of core-collapsed globular clusters

NASA Astrophysics Data System (ADS)

Bianchini, P.; Webb, J. J.; Sills, A.; Vesperini, E.

2018-03-01

Dynamical evolution drives globular clusters towards core collapse, which strongly shapes their internal properties. Diagnostics of core collapse have so far been based on photometry only, namely on the study of the concentration of the density profiles. Here, we present a new method to robustly identify core-collapsed clusters based on the study of their stellar kinematics. We introduce the kinematic concentration parameter, ck, the ratio between the global and local degree of energy equipartition reached by a cluster, and show through extensive direct N-body simulations that clusters approaching core collapse and in the post-core collapse phase are strictly characterized by ck > 1. The kinematic concentration provides a suitable diagnostic to identify core-collapsed clusters, independent from any other previous methods based on photometry. We also explore the effects of incomplete radial and stellar mass coverage on the calculation of ck and find that our method can be applied to state-of-art kinematic data sets.

How Fast is Collapse of Proteins During Folding?

NASA Astrophysics Data System (ADS)

Chahine, J.; Onuchic, J. N.; Socci, N. D.

1998-03-01

Recent experiments in fast folding proteins are now starting to address the question of how fast is collapse relative to the total folding time. Using minimalist models, we are able to investigate the way in which different scenarios of folding can arise depending on the interplay between the collapse order parameter and the order parameter sensitive to specific tertiary contacts. Most of our earlier studies have focused on the limit that collapse is very fast compared to the total folding time. In this work we focus on the opposite limit, i.e., at the folding temperature, collapse and folding occurs simultaneously. The folding mechanism becomes very different in this limit. Particularly, the non-specific collapse transition, that occurs at temperatures higher than the folding temperature for the fast collapse limit, now occurs between the folding and the glass temperature. We show how this transition can be identified and its consequences for the folding kinetics.

Dynamic water patterns change the stability of the collapsed filter conformation of the KcsA K+ channel

PubMed Central

2017-01-01

The selectivity filter of the KcsA K+ channel has two typical conformations—the conductive and the collapsed conformations, respectively. The transition from the conductive to the collapsed filter conformation can represent the process of inactivation that depends on many environmental factors. Water molecules permeating behind the filter can influence the collapsed filter stability. Here we perform the molecular dynamics simulations to study the stability of the collapsed filter of the KcsA K+ channel under the different water patterns. We find that the water patterns are dynamic behind the collapsed filter and the filter stability increases with the increasing number of water molecules. In addition, the stability increases significantly when water molecules distribute uniformly behind the four monomeric filter chains, and the stability is compromised if water molecules only cluster behind one or two adjacent filter chains. The altered filter stabilities thus suggest that the collapsed filter can inactivate gradually under the dynamic water patterns. We also demonstrate how the different water patterns affect the filter recovery from the collapsed conformation. PMID:29049423

Dynamic water patterns change the stability of the collapsed filter conformation of the KcsA K+ channel.

PubMed

Wu, Di

2017-01-01

The selectivity filter of the KcsA K+ channel has two typical conformations-the conductive and the collapsed conformations, respectively. The transition from the conductive to the collapsed filter conformation can represent the process of inactivation that depends on many environmental factors. Water molecules permeating behind the filter can influence the collapsed filter stability. Here we perform the molecular dynamics simulations to study the stability of the collapsed filter of the KcsA K+ channel under the different water patterns. We find that the water patterns are dynamic behind the collapsed filter and the filter stability increases with the increasing number of water molecules. In addition, the stability increases significantly when water molecules distribute uniformly behind the four monomeric filter chains, and the stability is compromised if water molecules only cluster behind one or two adjacent filter chains. The altered filter stabilities thus suggest that the collapsed filter can inactivate gradually under the dynamic water patterns. We also demonstrate how the different water patterns affect the filter recovery from the collapsed conformation.

Numeric simulation of relativistic stellar core collapse and the formation of Reissner-Nordstroem black holes

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

Ghezzi, Cristian R.; Letelier, Patricio S.

2007-01-15

The time evolution of a set of 22M{sub {center_dot}} unstable charged stars that collapse is computed integrating the Einstein-Maxwell equations. The model simulates the collapse of a spherical star that had exhausted its nuclear fuel and has or acquires a net electric charge in its core while collapsing. When the charge-to-mass ratio is Q/{radical}(G)M{>=}1, the star does not collapse but spreads. On the other hand, a different physical behavior is observed with a charge-to-mass ratio of 1>Q/{radical}(G)M>0.1. In this case, the collapsing matter forms a bubble enclosing a lower density core. We discuss an immediate astrophysical consequence of these resultsmore » that is a more efficient neutrino trapping during the stellar collapse and an alternative mechanism for powerful supernova explosions. The outer space-time of the star is the Reissner-Nordstroem solution that matches smoothly with our interior numerical solution; thus the collapsing models form Reissner-Nordstroem black holes.« less

Effects of international football matches on ambulance call profiles and volumes during the 2006 World Cup.

PubMed

Deakin, Charles D; Thompson, Fizz; Gibson, Caroline; Green, Mark

2007-06-01

Prompt ambulance attendance is aimed at improving patient care. With finite resources struggling to meet performance targets, unforeseen demand precludes the ability to tailor resources to cope with increased call volumes, and can have a marked detrimental effect on performance and hence patient care. The effects of the 2006 World Cup football matches on call volumes and profiles were analysed to understand how public events can influence demands on the ambulance service. All emergency calls to the Hampshire Ambulance Service NHS Trust (currently the Hampshire Division of South Central Ambulance Service, Winchester, UK) during the first weekend of the 2006 World Cup football matches were analysed by call volume and classification of call (call type). On the day of the first football match, call volume was over 50% higher than that on a typical Saturday, with distinct peaks before and after the inaugural match. Call profile analysis showed increases in alcohol-related emergencies, including collapse, unconsciousness, assault and road traffic accidents. The increase in assaults was particularly marked at the end of each match and increased again into the late evening. A detailed mapping of call volumes and profiles during the World Cup football shows a significant increase in overall emergency calls, mostly alcohol related. Mapping of limited resources to these patterns will allow improved responses to emergency calls.

Effects of international football matches on ambulance call profiles and volumes during the 2006 World Cup

PubMed Central

Deakin, Charles D; Thompson, Fizz; Gibson, Caroline; Green, Mark

2007-01-01

Background Prompt ambulance attendance is aimed at improving patient care. With finite resources struggling to meet performance targets, unforeseen demand precludes the ability to tailor resources to cope with increased call volumes, and can have a marked detrimental effect on performance and hence patient care. The effects of the 2006 World Cup football matches on call volumes and profiles were analysed to understand how public events can influence demands on the ambulance service. Methods All emergency calls to the Hampshire Ambulance Service NHS Trust (currently the Hampshire Division of South Central Ambulance Service, Winchester, UK) during the first weekend of the 2006 World Cup football matches were analysed by call volume and classification of call (call type). Results On the day of the first football match, call volume was over 50% higher than that on a typical Saturday, with distinct peaks before and after the inaugural match. Call profile analysis showed increases in alcohol‐related emergencies, including collapse, unconsciousness, assault and road traffic accidents. The increase in assaults was particularly marked at the end of each match and increased again into the late evening. Conclusion A detailed mapping of call volumes and profiles during the World Cup football shows a significant increase in overall emergency calls, mostly alcohol related. Mapping of limited resources to these patterns will allow improved responses to emergency calls. PMID:17513536

The effect of giant flank collapses on magma pathways and location of volcanic vents

NASA Astrophysics Data System (ADS)

Maccaferri, Francesco; Richter, Nicole; Walter, Thomas

2017-04-01

Flank collapses have been identified at tall volcanoes and ocean islands worldwide. They are recurrent processes, significantly contributing to the morphological and structural evolution of volcanic edifices, and they often occur in interaction with magmatic activity. Moreover, it has been observed that the intrusion pathways and eruption's sites often differ before and after flank collapses. While it is understood that dyke intrusions might destabilise a volcano flank, and a moving flank might create the space needed for further intrusions, the effect of collapses on the magma pathways has been rarely addressed. Here we use a boundary element model for dyke propagation to study the effect of the stress redistribution due to a flank collapse on the location of eruptive vents. We use our model to simulate the path of magmatic intrusion after the collapse of the eastern flank of Fogo Volcano, Cabe Verde. We find that the competition between loading stress due to the volcanic edifice and unloading due to the collapse of a flank favours magmatic activity to cluster within the collapse scar, displaced with respect to the pre-collapse volcanic centre. Our results are compared with geomorphological observations at Fogo Island and are discussed in the general context of the long-term evolution intraplate volcanic ocean islands worldwide.

Late Cenozoic regional collapse due to evaporite flow and Dissolution in the Carbondale Collapse Center, West-Central Colorado

USGS Publications Warehouse

Kirkham, R.M.; Streufert, R.K.; Budahn, J.R.; Kunk, Michael J.; Perry, W.J.

2001-01-01

Dissolution and flow of Pennsylvanian evaporitic rocks in west-central Colorado created the Carbondale Collapse Center, a 450 mi2 structural depression with about 4,000 ft of vertical collapse during the late Cenozoic. This paper describes evidence of collapse in the lower Roaring Fork River valley. Both the lateral extent and amount of vertical collapse is constrained by deformed upper Cenozoic volcanic rocks that have been correlated using field mapping, 40Ar/39Ar geochronology, geochemistry, and paleomagnetism. The Carbondale Collapse Center is one of at least two contiguous areas that have experienced major evaporite tectonism during the late Cenozoic. Historic sinkholes, deformed Holocene deposits, and modern high-salinity loads in the rivers and thermal springs indicate the collapse process continues today. Flow of evaporitic rocks is an important element in the collapse process, and during initial stages of collapse it was probably the primary causative mechanism. Dissolution, however, is the ultimate means by which evaporite is removed from the collapse area. As the Roaring Fork River began to rapidly down-cut through a broad volcanic plateau during the late Miocene, the underlying evaporite beds were subjected to differential overburden pressures. The evaporitic rocks flowed from beneath the upland areas where overburden pressures remained high, toward the Roaring Fork River Valley where the pressures were much lower. Along the valley the evaporitic rocks rose upward, sometimes as diapirs, forming or enhancing a valley anticline in bedrock and locally upwarping Pleistocene terraces. Wherever the evaporites encountered relatively fresh ground water, they were dissolved, forming underground voids into which overlying bedrock and surficial deposits subsided. The saline ground water eventually discharged to streams and rivers through thermal springs and by seepage into alluvial aquifers.

A History of Collapse Factor Modeling and Empirical Data for Cryogenic Propellant Tanks

NASA Technical Reports Server (NTRS)

deQuay, Laurence; Hodge, B. Keith

2010-01-01

One of the major technical problems associated with cryogenic liquid propellant systems used to supply rocket engines and their subassemblies and components is the phenomenon of propellant tank pressurant and ullage gas collapse. This collapse is mainly caused by heat transfer from ullage gas to tank walls and interfacing propellant, which are both at temperatures well below those of this gas. Mass transfer between ullage gas and cryogenic propellant can also occur and have minor to significant secondary effects that can increase or decrease ullage gas collapse. Pressurant gas is supplied into cryogenic propellant tanks in order to initially pressurize these tanks and then maintain required pressures as propellant is expelled from these tanks. The net effect of pressurant and ullage gas collapse is increased total mass and mass flow rate requirements of pressurant gases. For flight vehicles this leads to significant and undesirable weight penalties. For rocket engine component and subassembly ground test facilities this results in significantly increased facility hardware, construction, and operational costs. "Collapse Factor" is a parameter used to quantify the pressurant and ullage gas collapse. Accurate prediction of collapse factors, through analytical methods and modeling tools, and collection and evaluation of collapse factor data has evolved over the years since the start of space exploration programs in the 1950 s. Through the years, numerous documents have been published to preserve results of studies associated with the collapse factor phenomenon. This paper presents a summary and selected details of prior literature that document the aforementioned studies. Additionally other literature that present studies and results of heat and mass transfer processes, related to or providing important insights or analytical methods for the studies of collapse factor, are presented.

Atlantic freshwater balance in the hysteresis of the meridional overturning circulation

NASA Astrophysics Data System (ADS)

Gregory, J. M.; Saenko, O. A.

2003-04-01

We have studied the hysteresis behaviour of the Atlantic meridional overturning circulation (AMO) in the UVic climate model, which comprises an ocean GCM coupled to an energy-moisture balance atmosphere model and a dynamic-thermodynamic sea ice model, all with a resolution of 3.6x1.8 degrees. As with some other models, we find that a slowly increasing freshwater flux applied to the north Atlantic causes the AMO to collapse rapidly when it passes a threshold, and that it returns equally quickly when the freshwater forcing falls below a negative freshwater flux threshold. During the collapse, the Atlantic becomes less saline because of the import of about 80 Sv yr of freshwater by the ocean across 30S; during the switch-on this freshwater is exported again. These abrupt import and export of freshwater at 30S of the Atlantic are associated with, respectively, the appearance and disappearance of a shallower reverse overturning circulation south of the Equator. Qualitatively similar hysteresis behaviour, with the same salinity flip-flop, can be produced by an internal transfer of water within the Atlantic from low to high latitudes, with no net freshwater forcing input north of 30S.

Habitat collapse due to overgrazing threatens turtle conservation in marine protected areas.

PubMed

Christianen, Marjolijn J A; Herman, Peter M J; Bouma, Tjeerd J; Lamers, Leon P M; van Katwijk, Marieke M; van der Heide, Tjisse; Mumby, Peter J; Silliman, Brian R; Engelhard, Sarah L; van de Kerk, Madelon; Kiswara, Wawan; van de Koppel, Johan

2014-02-22

Marine protected areas (MPAs) are key tools for combatting the global overexploitation of endangered species. The prevailing paradigm is that MPAs are beneficial in helping to restore ecosystems to more 'natural' conditions. However, MPAs may have unintended negative effects when increasing densities of protected species exert destructive effects on their habitat. Here, we report on severe seagrass degradation in a decade-old MPA where hyper-abundant green turtles adopted a previously undescribed below-ground foraging strategy. By digging for and consuming rhizomes and roots, turtles create abundant bare gaps, thereby enhancing erosion and reducing seagrass regrowth. A fully parametrized model reveals that the ecosystem is approaching a tipping point, where consumption overwhelms regrowth, which could potentially lead to complete collapse of the seagrass habitat. Seagrass recovery will not ensue unless turtle density is reduced to nearly zero, eliminating the MPA's value as a turtle reserve. Our results reveal an unrecognized, yet imminent threat to MPAs, as sea turtle densities are increasing at major nesting sites and the decline of seagrass habitat forces turtles to concentrate on the remaining meadows inside reserves. This emphasizes the need for policy and management approaches that consider the interactions of protected species with their habitat.

Evolution of bubble clouds induced by pulsed cavitational ultrasound therapy - histotripsy.

PubMed

Xu, Zhen; Raghavan, M; Hall, T L; Mycek, M-A; Fowlkes, J B

2008-05-01

Mechanical tissue fractionation can be achieved using successive, high-intensity ultrasound pulses in a process termed histotripsy. Histotripsy has many potential clinical applications where noninvasive tissue removal is desired. The primary mechanism for histotripsy is believed to be cavitation. Using fast-gated imaging, this paper studies the evolution of a cavitating bubble cloud induced by a histotripsy pulse (10 and 14 cycles) at peak negative pressures exceeding 21MPa. Bubble clouds are generated inside a gelatin phantom and at a tissue-water interface, representing two situations encountered clinically. In both environments, the imaging results show that the bubble clouds share the same evolutionary trend. The bubble cloud and individual bubbles in the cloud were generated by the first cycle of the pulse, grew with each cycle during the pulse, and continued to grow and collapsed several hundred microseconds after the pulse. For example, the bubbles started under 10 microm, grew to 50 microm during the pulse, and continued to grow 100 microm after the pulse. The results also suggest that the bubble clouds generated in the two environments differ in growth and collapse duration, void fraction, shape, and size. This study furthers our understanding of the dynamics of bubble clouds induced by histotripsy.

Habitat collapse due to overgrazing threatens turtle conservation in marine protected areas

PubMed Central

Christianen, Marjolijn J. A.; Herman, Peter M. J.; Bouma, Tjeerd J.; Lamers, Leon P. M.; van Katwijk, Marieke M.; van der Heide, Tjisse; Mumby, Peter J.; Silliman, Brian R.; Engelhard, Sarah L.; van de Kerk, Madelon; Kiswara, Wawan; van de Koppel, Johan

2014-01-01

Marine protected areas (MPAs) are key tools for combatting the global overexploitation of endangered species. The prevailing paradigm is that MPAs are beneficial in helping to restore ecosystems to more ‘natural’ conditions. However, MPAs may have unintended negative effects when increasing densities of protected species exert destructive effects on their habitat. Here, we report on severe seagrass degradation in a decade-old MPA where hyper-abundant green turtles adopted a previously undescribed below-ground foraging strategy. By digging for and consuming rhizomes and roots, turtles create abundant bare gaps, thereby enhancing erosion and reducing seagrass regrowth. A fully parametrized model reveals that the ecosystem is approaching a tipping point, where consumption overwhelms regrowth, which could potentially lead to complete collapse of the seagrass habitat. Seagrass recovery will not ensue unless turtle density is reduced to nearly zero, eliminating the MPA's value as a turtle reserve. Our results reveal an unrecognized, yet imminent threat to MPAs, as sea turtle densities are increasing at major nesting sites and the decline of seagrass habitat forces turtles to concentrate on the remaining meadows inside reserves. This emphasizes the need for policy and management approaches that consider the interactions of protected species with their habitat. PMID:24403341

Elastic Properties across the y→α Volume Collapse in Cerium versus Pressure and Temperature

DOE PAGES

Lipp, M. J.; Jenei, Zs.; Cynn, H.; ...

2017-10-31

Here, the longitudinal and transverse sound speeds, c L and c T, of polycrystalline cerium were measured isothermally vs pressure up to the critical temperature across the iso-structural γ-α volume collapse (VC) phase transition. We deduce values for the adiabatic bulk modulus BS, the shear modulus G = ρc T 2, the Poisson’s ratio ν and the Debye temperature, θ D(p). We find that the elastic constant C 12 is solely responsible for the decrease of B S with pressure towards the VC at RT. With increasing temperature, the lattice contribution ΔS vib(γ→α) to the total entropy change across themore » VC decreases more rapidly to zero than the total entropy itself suggesting that another mechanism, possibly disorder, assists in stabilizing the γ-phase entropically against the α-phase. Also, with increasing temperature, the Poisson’s ratio becomes negative near the VC transition, meaning that cerium metal takes on auxetic characteristics over a small pressure range. At the critical point the Poisson’s ratio ought to be -1, since the isothermal bulk modulus vanishes and the shear modulus remains nonzero.« less

Elastic Properties across the y→α Volume Collapse in Cerium versus Pressure and Temperature

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

Lipp, M. J.; Jenei, Zs.; Cynn, H.

Here, the longitudinal and transverse sound speeds, c L and c T, of polycrystalline cerium were measured isothermally vs pressure up to the critical temperature across the iso-structural γ-α volume collapse (VC) phase transition. We deduce values for the adiabatic bulk modulus BS, the shear modulus G = ρc T 2, the Poisson’s ratio ν and the Debye temperature, θ D(p). We find that the elastic constant C 12 is solely responsible for the decrease of B S with pressure towards the VC at RT. With increasing temperature, the lattice contribution ΔS vib(γ→α) to the total entropy change across themore » VC decreases more rapidly to zero than the total entropy itself suggesting that another mechanism, possibly disorder, assists in stabilizing the γ-phase entropically against the α-phase. Also, with increasing temperature, the Poisson’s ratio becomes negative near the VC transition, meaning that cerium metal takes on auxetic characteristics over a small pressure range. At the critical point the Poisson’s ratio ought to be -1, since the isothermal bulk modulus vanishes and the shear modulus remains nonzero.« less

Ponzi scheme diffusion in complex networks

NASA Astrophysics Data System (ADS)

Zhu, Anding; Fu, Peihua; Zhang, Qinghe; Chen, Zhenyue

2017-08-01

Ponzi schemes taking the form of Internet-based financial schemes have been negatively affecting China's economy for the last two years. Because there is currently a lack of modeling research on Ponzi scheme diffusion within social networks yet, we develop a potential-investor-divestor (PID) model to investigate the diffusion dynamics of Ponzi scheme in both homogeneous and inhomogeneous networks. Our simulation study of artificial and real Facebook social networks shows that the structure of investor networks does indeed affect the characteristics of dynamics. Both the average degree of distribution and the power-law degree of distribution will reduce the spreading critical threshold and will speed up the rate of diffusion. A high speed of diffusion is the key to alleviating the interest burden and improving the financial outcomes for the Ponzi scheme operator. The zero-crossing point of fund flux function we introduce proves to be a feasible index for reflecting the fast-worsening situation of fiscal instability and predicting the forthcoming collapse. The faster the scheme diffuses, the higher a peak it will reach and the sooner it will collapse. We should keep a vigilant eye on the harm of Ponzi scheme diffusion through modern social networks.

The Cretaceous-Tertiary boundary marine extinction and global primary productivity collapse

NASA Technical Reports Server (NTRS)

Zachos, J. C.; Arthus, M. A.; Dean, W. E.

1988-01-01

The extinction of marine phyto-and zoo-plankton across the K-T boundary has been well documented. Such an event may have resulted in decreased photosynthetic fixation of carbon in surface waters and a collapse of the food chain in the marine biosphere. Because the vertical and horizontal distribution of the carbon isotopic composition of total dissolved carton (TDC) in the modern ocean is controlled by the transfer of organic carbon from the surface to deep reservoirs, it follows that a major disruption of the marine biosphere would have had a major effect on the distribution of carbon isotopes in the ocean. Negative carbon isotope excursions have been identified at many marine K-T boundary sequences worldwide and are interpreted as a signal of decreased oceanic primary productivity. However, the magnitude, duration and consequences of this productivity crisis have been poorly constrained. On the basis of planktonic and benthic calcareous microfossil carbon isotope and other geochemical data from DSDP Site 577 located on the Shatsky Rise in the north-central Pacific, as well as other sites, researchers have been able to provide a reasonable estimate of the duration and magnitude of this event.

Hydrostatic collapse research in support of the Oman India gas pipeline

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

Stark, P.R.; McKeehan, D.S.

1995-12-01

This paper provides a summary of the collapse test program conducted as part of the technical development for the Ultra Deep Oman to India Pipeline. The paper describes the motivation for conducting the collapse test program, outlines the test objectives and procedures, presents the results obtained, and draws conclusions on the factors affecting collapse resistance.

Catastrophic volcanic collapse: relation to hydrothermal processes.

PubMed

López, D L; Williams, S N

1993-06-18

Catastrophic volcanic collapse, without precursory magmatic activity, is characteristic of many volcanic disasters. The extent and locations of hydrothermal discharges at Nevado del Ruiz volcano, Colombia, suggest that at many volcanoes collapse may result from the interactions between hydrothermal fluids and the volcanic edifice. Rock dissolution and hydrothermal mineral alteration, combined with physical triggers such as earth-quakes, can produce volcanic collapse. Hot spring water compositions, residence times, and flow paths through faults were used to model potential collapse at Ruiz. Caldera dimensions, deposits, and alteration mineral volumes are consistent with parameters observed at other volcanoes.

The Safety and efficacy of a new self-expandable intratracheal nitinol stent for the tracheal collapse in dogs

PubMed Central

Kim, Joon-young; Han, Hyun-jung; Yun, Hun-young; Lee, Bora; Jang, Ha-young; Eom, Ki-dong; Park, Hee-myung

2008-01-01

To evaluate the potential utility of a self-expandable intratracheal nitinol stent with flared ends for the treatment of tracheal collapse in dogs, endotracheal stenting therapy was performed under fluoroscopic guidance in four dogs with severe tracheal collapse. During the 4 to 7 month follow-up, after stent implantation, clinical signs, including dyspnea and respiratory distress, dramatically improved in all dogs. The radiographs showed that the implanted stents improved the tracheal collapse, and there were no side effects such as collapse, shortening or migration of the stents. In conclusion, the self-expandable intratracheal nitinol stents provided adequate stability to the trachea and were effective for attenuating the clinical signs associated with severe tracheal collapse. PMID:18296893

The absence of horizon in black-hole formation

NASA Astrophysics Data System (ADS)

Ho, Pei-Ming

2016-08-01

With the back-reaction of Hawking radiation taken into consideration, the work of Kawai, Matsuo and Yokokura [1] has shown that, under a few assumptions, the collapse of matter does not lead to event horizon nor apparent horizon. In this paper, we relax their assumptions and elaborate on the space-time geometry of a generic collapsing body with spherical symmetry. The geometry outside the collapsing sphere is found to be approximated by the geometry outside the white-hole horizon, hence the collapsing matter remains outside the Schwarzschild radius. As particles in Hawking radiation are created in the vicinity of the collapsing matter, the information loss paradox is alleviated. Assuming that the collapsing body evaporates within finite time, there is no event horizon.

Granular Silo collapse: an experimental study

NASA Astrophysics Data System (ADS)

Clement, Eric; Gutierriez, Gustavo; Boltenhagen, Philippe; Lanuza, Jose

2008-03-01

We present an experimental work that develop some basic insight into the pre-buckling behavior and the buckling transition toward plastic collapse of a granular silo. We study different patterns of deformation generated on thin paper cylindrical shells during granular discharge. We study the collapse threshold for different bed height, flow rates and grain sizes. We compare the patterns that appear during the discharge of spherical beads, with those obtained in the axially compressed cylindrical shells. When the height of the granular column is close to the collapse threshold, we describe a ladder like pattern that rises around the cylinder surface in a spiral path of diamond shaped localizations, and develops into a plastic collapsing fold that grows around the collapsing silo.

Emotional Reactivity and Regulation in Anxious and Non-anxious Youth: A Cell-Phone Ecological Momentary Assessment Study

PubMed Central

Tan, Patricia Z.; Forbes, Erika E.; Dahl, Ronald E.; Ryan, Neal D.; Siegle, Greg J.; Ladouceur, Cecile D.; Silk, Jennifer S.

2011-01-01

Background Reviews have highlighted anxious youths’ affective disturbances, specifically, elevated negative emotions and reliance on ineffective emotion regulation strategies. However, no study has examined anxious youth’s emotional reactivity and regulation in real-world contexts. Methods This study utilized an ecological momentary assessment approach to compare real-world emotional experiences of 65 youth with generalized anxiety disorder, social anxiety disorder, or social phobia (ANX) and 65 age-matched healthy controls (CON), ages 9–13 years. Results Hierarchical linear models revealed that ANX reported higher levels of average past-hour peak intensity of nervous, sad, and upset emotions than CON youth but similar levels during momentary reports of current emotion. As expected, ANX youth reported more frequent physiological reactions in response to a negative event; however there were no group differences in how frequently they used cognitive-behavioral strategies. Avoidance, distraction, and problem-solving were associated with the down-regulation of all negative emotions except nervousness for both ANX and CON youth; however, group differences emerged for acceptance, rumination, and physiological responding. Conclusions In real-world contexts, ANX youth do not report higher levels of momentary negative emotions but do report heightened negative emotions in response to challenging events. Moreover, ANX youth report no differences in how frequently they use adaptive regulatory strategies but are more likely to have physiological responses to challenging events. They are also less effective at using some strategies to down-regulate negative emotion than CON youth. PMID:22176136

Abrupt climate change around 4 ka BP: Role of the Thermohaline circulation as indicated by a GCM experiment

NASA Astrophysics Data System (ADS)

Wang, Shaowu; Zhou, Tianjun; Cai, Jingning; Zhu, Jinhong; Xie, Zhihui; Gong, Daoyi

2004-04-01

A great deal of palaeoenvironmental and palaeoclimatic evidence suggests that a predominant temperature drop and an aridification occurred at ca. 4.0 ka BP. Palaeoclimate studies in China support this dedution. The collapse of ancient civilizations at ca. 4.0 ka BP in the Nile Valley and Mesopotamia has been attributed to climate-induced aridification. A widespread alternation of the ancient cultures was also found in China at ca. 4.0 ka BP in concert with the collapse of the civilizations in the Old World. Palaeoclimatic studies indicate that the abrupt climate change at 4.0 ka BP is one of the realizations of the cold phase in millennial scale climate oscillations, which may be related to the modulation of the Thermohaline Circulation (THC) over the Atlantic Ocean. Therefore, this study conducts a numerical experiment of a GCM with SST forcing to simulate the impact of the weakening of the THC. Results show a drop in temperature from North Europe, the northern middle East Asia, and northern East Asia and a significant reduction of precipitation in East Africa, the Middle East, the Indian Peninsula, and the Yellow River Valley. This seems to support the idea that coldness and aridification at ca. 4.0 ka BP was caused by the weakening of the THC.

What's on Your Mind? Conversation Topics Chosen by People With Degenerative Cognitive-Linguistic Disorders for Communication Boards

PubMed Central

Daniels, Darlene; Ettinger, Olivia; Mooney, Aimee; Noethe, Glory; Rowland, Charity

2015-01-01

Purpose Conversational topics chosen by a group of adults with degenerative cognitive-linguistic disorders for personalized communication board development were examined. The patient-generated themes commonly selected are presented to guide treatment planning and communication board development. Method Communication boards were created for 109 adults as part of a larger research project. One autobiographical topic that each participant would enjoy discussing multiple times was represented on each communication board with 16 pictures and word labels. For this review, topics were collapsed into general themes through a consensus process and examined by gender and age. Results Sixty unique conversational topics were identified from 109 participants and collapsed into 9 general themes: Hobbies, Family, Travel, Work, Home/Places I've Lived, Sports/Fitness, Religion, Animals, and World War II. Age and gender produced variations in themes chosen, though no significance in rank orders was found across groups. Conclusions Topics selected by adults with degenerative cognitive-linguistic disorders for communication boards resemble common conversational adult themes and do not center around basic needs or medical issues. Differences in gender and age for topic selection tend to be based on traditional roles. These general themes should be used when creating personalized communication boards for those who benefit from conversational aids. PMID:25835511

Rural to Urban Population Density Scaling of Crime and Property Transactions in English and Welsh Parliamentary Constituencies.

PubMed

Hanley, Quentin S; Lewis, Dan; Ribeiro, Haroldo V

2016-01-01

Urban population scaling of resource use, creativity metrics, and human behaviors has been widely studied. These studies have not looked in detail at the full range of human environments which represent a continuum from the most rural to heavily urban. We examined monthly police crime reports and property transaction values across all 573 Parliamentary Constituencies in England and Wales, finding that scaling models based on population density provided a far superior framework to traditional population scaling. We found four types of scaling: i) non-urban scaling in which a single power law explained the relationship between the metrics and population density from the most rural to heavily urban environments, ii) accelerated scaling in which high population density was associated with an increase in the power-law exponent, iii) inhibited scaling where the urban environment resulted in a reduction in the power-law exponent but remained positive, and iv) collapsed scaling where transition to the high density environment resulted in a negative scaling exponent. Urban scaling transitions, when observed, took place universally between 10 and 70 people per hectare. This study significantly refines our understanding of urban scaling, making clear that some of what has been previously ascribed to urban environments may simply be the high density portion of non-urban scaling. It also makes clear that some metrics undergo specific transitions in urban environments and these transitions can include negative scaling exponents indicative of collapse. This study gives promise of far more sophisticated scale adjusted metrics and indicates that studies of urban scaling represent a high density subsection of overall scaling relationships which continue into rural environments.

Systemic and intensifying drought induces collapse and replacement of native fishes: a time-series approach

NASA Astrophysics Data System (ADS)

Ruhi, A.; Olden, J. D.; Sabo, J. L.

2015-12-01

In the American Southwest, hydrologic drought has become a new normal as a result of increasing human appropriation of freshwater resources and increased aridity associated with global warming. Although drought has often been touted to threaten freshwater biodiversity, connecting drought to extinction risk of highly-imperiled faunas remains a challenge. Here we combine time-series methods from signal processing and econometrics to analyze a spatially comprehensive and long-term dataset to link discharge variation and community abundance of fish across the American Southwest. This novel time series framework identifies ongoing trends in daily discharge anomalies across the Southwest, quantifies the effect of the historical hydrologic drivers on fish community abundance, and allows us to simulate species trajectories and range-wide risk of decline (quasiextinction) under scenarios of future climate. Spectral anomalies are declining over the last 30 years in at least a quarter of the stream gaging stations across the American Southwest and these anomalies are robust predictors of historical abundance of native and non-native fishes. Quasiextinction probabilities are high (>50 %) for nearly ¾ of the native species across several large river basins in the same region; and the negative trend in annual anomalies increases quasiextinction risk for native but reduces this risk for non-native fishes. These findings suggest that ongoing drought is causing range-wide collapse and replacement of native fish faunas, and that this homogenization of western fish faunas will continue given the prevailing negative trend in discharge anomalies. Additionally, this combination of methods can be applied elsewhere as long as environmental and biological long-term time-series data are available. Collectively, these methods allow identifying the link between hydroclimatic forcing and ecological responses and thus may help anticipating the potential impacts of ongoing and future hydrologic extremes in freshwater ecosystems.

Rural to Urban Population Density Scaling of Crime and Property Transactions in English and Welsh Parliamentary Constituencies

PubMed Central

Hanley, Quentin S.; Lewis, Dan; Ribeiro, Haroldo V.

2016-01-01

Urban population scaling of resource use, creativity metrics, and human behaviors has been widely studied. These studies have not looked in detail at the full range of human environments which represent a continuum from the most rural to heavily urban. We examined monthly police crime reports and property transaction values across all 573 Parliamentary Constituencies in England and Wales, finding that scaling models based on population density provided a far superior framework to traditional population scaling. We found four types of scaling: i) non-urban scaling in which a single power law explained the relationship between the metrics and population density from the most rural to heavily urban environments, ii) accelerated scaling in which high population density was associated with an increase in the power-law exponent, iii) inhibited scaling where the urban environment resulted in a reduction in the power-law exponent but remained positive, and iv) collapsed scaling where transition to the high density environment resulted in a negative scaling exponent. Urban scaling transitions, when observed, took place universally between 10 and 70 people per hectare. This study significantly refines our understanding of urban scaling, making clear that some of what has been previously ascribed to urban environments may simply be the high density portion of non-urban scaling. It also makes clear that some metrics undergo specific transitions in urban environments and these transitions can include negative scaling exponents indicative of collapse. This study gives promise of far more sophisticated scale adjusted metrics and indicates that studies of urban scaling represent a high density subsection of overall scaling relationships which continue into rural environments. PMID:26886219

Feeding group responses of a Neotropical termite assemblage to rain forest fragmentation.

PubMed

Davies, Richard G

2002-10-01

Biomass collapse and its associated microclimatic stresses within recently isolated rain forest fragments may negatively affect species diversity of most resident taxa. However, for some decomposer organisms, increased resource availability via accompanying tree die-off may effect positive responses, at least for a time, with implications for rates of nutrient cycling and greenhouse gas release. This study investigates the early effects of forest fragmentation on a Neotropical termite assemblage. Numbers of encounters (surrogate for relative abundance) and species richness of wood and leaf-litter feeders, soil feeders, and the whole assemblage, were studied across true forest islands and mainland sites at a hydroelectric reservoir in French Guiana. Results showed no overall effect of fragmentation on either total termite encounters or species richness. However, numbers of encounters and species richness of wood and leaf-litter feeders showed positive responses to forest fragmentation. By contrast, soil feeders showed a negative response for numbers of encounters and no significant effect for species richness. Environmental data suggest that increased tree die-off, and other edge effects associated with biomass collapse, were underway at the time of sampling. Resulting increase in resource availability may therefore explain the positive influence on wood and leaf-litter feeders. A possible decrease in predation pressure from ants with decrease in island size was not tested for, but was a likely effect of the flooded matrix habitat. Fragmentation effects on soil feeder encounters may be due to the energetic and microclimatic constraints of feeding lower down the humification gradient of termite food substrates, but were not sufficient to affect species richness. The patterns revealed suggest that rates of wood decomposition following tree die-off, and of soil nutrient cycling, under different rain forest fragmentation scenarios, merit further study.

Trazodone increases the respiratory arousal threshold in patients with obstructive sleep apnea and a low arousal threshold.

PubMed

Eckert, Danny J; Malhotra, Atul; Wellman, Andrew; White, David P

2014-04-01

The effect of common sedatives on upper airway physiology and breathing during sleep in obstructive sleep apnea (OSA) has been minimally studied. Conceptually, certain sedatives may worsen OSA in some patients. However, sleep and breathing could improve with certain sedatives in patients with OSA with a low respiratory arousal threshold. This study aimed to test the hypothesis that trazodone increases the respiratory arousal threshold in patients with OSA and a low arousal threshold. Secondary aims were to examine the effects of trazodone on upper airway dilator muscle activity, upper airway collapsibility, and breathing during sleep. Patients were studied on 4 separate nights according to a within-subjects cross-over design. Sleep physiology laboratory. Seven patients with OSA and a low respiratory arousal threshold. In-laboratory polysomnograms were obtained at baseline and after 100 mg of trazodone was administered, followed by detailed overnight physiology experiments under the same conditions. During physiology studies, continuous positive airway pressure was transiently lowered to measure arousal threshold (negative epiglottic pressure prior to arousal), dilator muscle activity (genioglossus and tensor palatini), and upper airway collapsibility (Pcrit). Trazodone increased the respiratory arousal threshold by 32 ± 6% (-11.5 ± 1.4 versus -15.3 ± 2.2 cmH2O, P < 0.01) but did not alter the apnea-hypopnea index (39 ± 12 versus 39 ± 11 events/h sleep, P = 0.94). Dilator muscle activity and Pcrit also did not systematically change with trazodone. Trazodone increases the respiratory arousal threshold in patients with obstructive sleep apnea and a low arousal threshold without major impairment in dilator muscle activity or upper airway collapsibility. However, the magnitude of change in arousal threshold was insufficient to overcome the compromised upper airway anatomy in these patients.

Ex vivo tracheomalacia model with 3D-printed external tracheal splint.

PubMed

Kaye, Rachel; Goldstein, Todd; Aronowitz, Danielle; Grande, Daniel A; Zeltsman, David; Smith, Lee P

2017-04-01

To design and evaluate an ex vivo model of tracheomalacia with and without a three-dimensional (3D)-printed external tracheal splint. Prospective, ex vivo animal trial. Three groups of ex vivo porcine tracheas were used: 1) control (unmanipulated trachea), 2) tracheomalacia (tracheal rings partially incised and crushed), and 3) splinted tracheomalacia (external custom tracheal splint fitted onto group 2 trachea). Each end of an ex vivo trachea was sealed with a custom-designed and 3D-printed cap; a transducer was placed through one end to measure the pressure inside the trachea. Although the negative pressure was applied to the tracheal lumen, the tracheal wall collapse was measured externally and internally using a bronchoscope. Each group had at least three recorded trials. Tracheal diameter was evaluated using ImageJ software (National Institutes of Health, Bethesda, MD) and was averaged between two raters. Average tracheal occlusion percentage was compared using Student t test. The average occlusion was 31% for group 1, 87.4% for group 2, and 20% for group 3. Significant differences were found between the control and tracheomalacia groups (P < 0.01) and the tracheomalacia and splinted tracheomalacia groups (P < 0.01). There was no significant difference between the control and splinted tracheomalacia groups (P = 0.13). Applied pressure was plotted against occlusion and regression line slope differed between the tracheomalacia (0.91) and control (0.12) or splinted tracheomalacia (0.39) groups. We demonstrate the potential for an ex vivo tracheomalacia model to reproduce airway collapse and show that this collapse can be treated successfully with a 3D-printed external splint. These results are promising and justify further studies. N/A. Laryngoscope, 127:950-955, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

PLAN2D - A PROGRAM FOR ELASTO-PLASTIC ANALYSIS OF PLANAR FRAMES

NASA Technical Reports Server (NTRS)

Lawrence, C.

1994-01-01

PLAN2D is a FORTRAN computer program for the plastic analysis of planar rigid frame structures. Given a structure and loading pattern as input, PLAN2D calculates the ultimate load that the structure can sustain before collapse. Element moments and plastic hinge rotations are calculated for the ultimate load. The location of hinges required for a collapse mechanism to form are also determined. The program proceeds in an iterative series of linear elastic analyses. After each iteration the resulting elastic moments in each member are compared to the reserve plastic moment capacity of that member. The member or members that have moments closest to their reserve capacity will determine the minimum load factor and the site where the next hinge is to be inserted. Next, hinges are inserted and the structural stiffness matrix is reformulated. This cycle is repeated until the structure becomes unstable. At this point the ultimate collapse load is calculated by accumulating the minimum load factor from each previous iteration and multiplying them by the original input loads. PLAN2D is based on the program STAN, originally written by Dr. E.L. Wilson at U.C. Berkeley. PLAN2D has several limitations: 1) Although PLAN2D will detect unloading of hinges it does not contain the capability to remove hinges; 2) PLAN2D does not allow the user to input different positive and negative moment capacities and 3) PLAN2D does not consider the interaction between axial and plastic moment capacity. Axial yielding and buckling is ignored as is the reduction in moment capacity due to axial load. PLAN2D is written in FORTRAN and is machine independent. It has been tested on an IBM PC and a DEC MicroVAX. The program was developed in 1988.

Simulation and analysis of collapsing vapor-bubble clusters with special emphasis on potentially erosive impact loads at walls

NASA Astrophysics Data System (ADS)

Ogloblina, Daria; Schmidt, Steffen J.; Adams, Nikolaus A.

2018-06-01

Cavitation is a process where a liquid evaporates due to a pressure drop and re-condenses violently. Noise, material erosion and altered system dynamics characterize for such a process for which shock waves, rarefaction waves and vapor generation are typical phenomena. The current paper presents novel results for collapsing vapour-bubble clusters in a liquid environment close to a wall obtained by computational fluid mechanics (CFD) simulations. The driving pressure initially is 10 MPa in the liquid. Computations are carried out by using a fully compressible single-fluid flow model in combination with a conservative finite volume method (FVM). The investigated bubble clusters (referred to as "clouds") differ by their initial vapor volume fractions, initial stand-off distances to the wall and by initial bubble radii. The effects of collapse focusing due to bubble-bubble interaction are analysed by investigating the intensities and positions of individual bubble collapses, as well as by the resulting shock-induced pressure field at the wall. Stronger interaction of the bubbles leads to an intensification of the collapse strength for individual bubbles, collapse focusing towards the center of the cloud and enhanced re-evaporation. The obtained results reveal collapse features which are common for all cases, as well as case-specific differences during collapse-rebound cycles. Simultaneous measurements of maximum pressures at the wall and within the flow field and of the vapor volume evolution show that not only the primary collapse but also subsequent collapses are potentially relevant for erosion.

The role of bank collapse on tidal creek ontogeny: A novel process-based model for bank retreat

NASA Astrophysics Data System (ADS)

Gong, Zheng; Zhao, Kun; Zhang, Changkuan; Dai, Weiqi; Coco, Giovanni; Zhou, Zeng

2018-06-01

Bank retreat in coastal tidal flats plays a primary role on the planimetric shape of tidal creeks and is commonly driven by both flow-induced bank erosion and gravity-induced bank collapse. However, existing modelling studies largely focus on bank erosion and overlook bank collapse. We build a bank retreat model coupling hydrodynamics, bank erosion and bank collapse. To simulate the process of bank collapse, a stress-deformation model is utilized to calculate the stress variation of bank soil after bank erosion, and the Mohr-Coulomb failure criterion is then applied to evaluate the stability of the tidal creek bank. Results show that the bank failure process can be categorized into three stages, i.e., shear failure at the bank toe (stage I), tensile failure on the bank top (stage II), and sectional cracking from the bank top to the toe (stage III). With only bank erosion, the planimetric shapes of tidal creeks are funneled due to the gradually seaward increasing discharge. In contrast to bank erosion, bank collapse is discontinuous, and the contribution of bank collapse to bank retreat can reach 85%, highlighting that the expansion of tidal creeks can be dominated by bank collapse process. The planimetric shapes of tidal creeks are funneled with a much faster expansion rate when bank collapse is considered. Overall, this study makes a further step toward more physical and realistic simulation of bank retreat in estuarine and coastal settings and the developed bank collapse module can be readily included in other morphodynamic models.

A mixed helium-oxygen shell in some core-collapse supernova progenitors

NASA Astrophysics Data System (ADS)

Gofman, Roni Anna; Gilkis, Avishai; Soker, Noam

2018-04-01

We evolve models of rotating massive stars up to the stage of iron core collapse using the MESA code and find a shell with a mixed composition of primarily helium and oxygen in some cases. In the parameter space of initial masses of 13-40M⊙ and initial rotation velocities of 0-450 kms-1 that we investigate, we find a mixed helium-oxygen (He-O) shell with a significant total He-O mass and with a helium to oxygen mass ratio in the range of 0.5-2 only for a small fraction of the models. While the shell formation due to mixing is instigated by rotation, the pre-collapse rotation rate is not very high. The fraction of models with a shell of He-O composition required for an energetic collapse-induced thermonuclear explosion is small, as is the fraction of models with high specific angular momentum, which can aid the thermonuclear explosion by retarding the collapse. Our results suggest that the collapse-induced thermonuclear explosion mechanism that was revisited recently can account for at most a small fraction of core-collapse supernovae. The presence of such a mixed He-O shell still might have some implications for core-collapse supernovae, such as some nucleosynthesis processes when jets are present, or might result in peculiar sub-luminous core-collapse supernovae.

Characterization of DNA condensates induced by poly(ethylene oxide) and polylysine.

PubMed Central

Laemmli, U K

1975-01-01

High-molecular-weight DNA is known to collapse into very compact particles in a salt solution containing polymers like poly(ethylene oxide) [(EO)n] or polyacrylate. The biological relevance of this phenomenon is suggested by our recent finding that high concentrations of the highly acidic internal peptides found in the mature T4 bacteriophage head, as well as poly(glutamic acid) and poly(aspartic acid), can collapse DNA in a similar manner. The structure of DNAs collapsed by various methods has been studied with electron microscope. We find (EO)n collapses T4 or T7 bacteriophage DNA into compact particles only slightly larger than the size of the T4 and T7 head, respectively. In contrast, polylysine collapses DNA into different types of structures. Double-stranded DNA collapsed with (EO)n is cut by the single-strand specific Neurospora crassa endonuclease (EC 3.1.4.21) into small fragments. Extensive digestion only occurs above the critical concentration of polymer required for DNA collapse, demonstrating the (EO)n-collapsed DNA contains enzyme-vulnerable regions (probably at each fold), which are preferentially attacked. The size of the DNA fragments produced by limit-digestion with the nuclease ranges between 200 and 400 base pairs when DNA is collapsed by (EO)n. Only fragments of DNA which are larger than 600 base pairs are cut by the endonuclease in (EO)n-containing solution. Images PMID:1060108

A mixed helium-oxygen shell in some core-collapse supernova progenitors

NASA Astrophysics Data System (ADS)

Gofman, Roni Anna; Gilkis, Avishai; Soker, Noam

2018-07-01

We evolve models of rotating massive stars up to the stage of iron core collapse using the MESA code and find a shell with a mixed composition of primarily helium and oxygen in some cases. In the parameter space of initial masses of 13-40 M⊙ and initial rotation velocities of 0-450 km s-1 that we investigate, we find a mixed helium-oxygen (He-O) shell with a significant total He-O mass and with a helium to oxygen mass ratio in the range of 0.5-2 only for a small fraction of the models. While the shell formation due to mixing is instigated by rotation, the pre-collapse rotation rate is not very high. The fraction of models with a shell of He-O composition required for an energetic collapse-induced thermonuclear explosion is small, as is the fraction of models with high specific angular momentum, which can aid the thermonuclear explosion by retarding the collapse. Our results suggest that the collapse-induced thermonuclear explosion mechanism that was revisited recently can account for at most a small fraction of core-collapse supernovae. The presence of such a mixed He-O shell still might have some implications for core-collapse supernovae, such as some nucleosynthesis processes when jets are present, or might result in peculiar sub-luminous core-collapse supernovae.

Entropies of negative incomes, Pareto-distributed loss, and financial crises.

PubMed

Gao, Jianbo; Hu, Jing; Mao, Xiang; Zhou, Mi; Gurbaxani, Brian; Lin, Johnny

2011-01-01

Health monitoring of world economy is an important issue, especially in a time of profound economic difficulty world-wide. The most important aspect of health monitoring is to accurately predict economic downturns. To gain insights into how economic crises develop, we present two metrics, positive and negative income entropy and distribution analysis, to analyze the collective "spatial" and temporal dynamics of companies in nine sectors of the world economy over a 19 year period from 1990-2008. These metrics provide accurate predictive skill with a very low false-positive rate in predicting downturns. The new metrics also provide evidence of phase transition-like behavior prior to the onset of recessions. Such a transition occurs when negative pretax incomes prior to or during economic recessions transition from a thin-tailed exponential distribution to the higher entropy Pareto distribution, and develop even heavier tails than those of the positive pretax incomes. These features propagate from the crisis initiating sector of the economy to other sectors.

Gravitational Collapse with Heat Flux and Gravitational Waves

NASA Astrophysics Data System (ADS)

Ahmad, Zahid; Ahmed, Qazi Zahoor; Awan, Abdul Sami

2013-10-01

In this paper, we investigated the cylindrical gravitational collapse with heat flux by considering the appropriate geometry of the interior and exterior spacetimes. For this purpose, we matched collapsing fluid to an exterior containing gravitational waves.The effects of heat flux on gravitational collapse are investigated and matched with the results obtained by Herrera and Santos (Class. Quantum Gravity 22:2407, 2005).

Can agricultural groundwater economies collapse? An inquiry into the pathways of four groundwater economies under threat

NASA Astrophysics Data System (ADS)

Petit, Olivier; Kuper, Marcel; López-Gunn, Elena; Rinaudo, Jean-Daniel; Daoudi, Ali; Lejars, Caroline

2017-09-01

The aim of this paper is to investigate the notion of collapse of agricultural groundwater economies using the adaptive-cycle analytical framework. This framework was applied to four case studies in southern Europe and North Africa to question and discuss the dynamics of agricultural groundwater economies. In two case studies (Saiss in Morocco and Clain basin in France), the imminent physical or socio-economic collapse was a major concern for stakeholders and the early signs of collapse led to re-organization of the groundwater economy. In the other two cases (Biskra in Algeria and Almeria in Spain), collapse was either not yet a concern or had been temporarily resolved through increased efficiency and access to additional water resources. This comparative analysis shows the importance of taking the early signs of collapse into account. These signs can be either related to resource depletion or to environmental and socio-economic impacts. Beyond these four case studies, the large number of groundwater economies under threat in (semi-)arid areas should present a warning regarding their possible collapse. Collapse can have severe and irreversible consequences in some cases, but it can also mean new opportunities and changes.

Collapse susceptibility mapping in karstified gypsum terrain (Sivas basin - Turkey) by conditional probability, logistic regression, artificial neural network models

NASA Astrophysics Data System (ADS)

Yilmaz, Isik; Keskin, Inan; Marschalko, Marian; Bednarik, Martin

2010-05-01

This study compares the GIS based collapse susceptibility mapping methods such as; conditional probability (CP), logistic regression (LR) and artificial neural networks (ANN) applied in gypsum rock masses in Sivas basin (Turkey). Digital Elevation Model (DEM) was first constructed using GIS software. Collapse-related factors, directly or indirectly related to the causes of collapse occurrence, such as distance from faults, slope angle and aspect, topographical elevation, distance from drainage, topographic wetness index- TWI, stream power index- SPI, Normalized Difference Vegetation Index (NDVI) by means of vegetation cover, distance from roads and settlements were used in the collapse susceptibility analyses. In the last stage of the analyses, collapse susceptibility maps were produced from CP, LR and ANN models, and they were then compared by means of their validations. Area Under Curve (AUC) values obtained from all three methodologies showed that the map obtained from ANN model looks like more accurate than the other models, and the results also showed that the artificial neural networks is a usefull tool in preparation of collapse susceptibility map and highly compatible with GIS operating features. Key words: Collapse; doline; susceptibility map; gypsum; GIS; conditional probability; logistic regression; artificial neural networks.

Nanomaterials under extreme environments: A study of structural and dynamic properties using reactive molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Shekhar, Adarsh

Nanotechnology is becoming increasingly important with the continuing advances in experimental techniques. As researchers around the world are trying to expand the current understanding of the behavior of materials at the atomistic scale, the limited resolution of equipment, both in terms of time and space, act as roadblocks to a comprehensive study. Numerical methods, in general and molecular dynamics, in particular act as able compliment to the experiments in our quest for understanding material behavior. In this research work, large scale molecular dynamics simulations to gain insight into the mechano-chemical behavior under extreme conditions of a variety of systems with many real world applications. The body of this work is divided into three parts, each covering a particular system: 1) Aggregates of aluminum nanoparticles are good solid fuel due to high flame propagation rates. Multi-million atom molecular dynamics simulations reveal the mechanism underlying higher reaction rate in a chain of aluminum nanoparticles as compared to an isolated nanoparticle. This is due to the penetration of hot atoms from reacting nanoparticles to an adjacent, unreacted nanoparticle, which brings in external heat and initiates exothermic oxidation reactions. 2) Cavitation bubbles readily occur in fluids subjected to rapid changes in pressure. We use billion-atom reactive molecular dynamics simulations on a 163,840-processor BlueGene/P supercomputer to investigate chemical and mechanical damages caused by shock-induced collapse of nanobubbles in water near amorphous silica. Collapse of an empty nanobubble generates high-speed nanojet, resulting in the formation of a pit on the surface. The pit contains a large number of silanol groups and its volume is found to be directly proportional to the volume of the nanobubble. The gas-filled bubbles undergo partial collapse and consequently the damage on the silica surface is mitigated. 3) The structure and dynamics of water confined in nanoporous silica are different from that of bulk water, and insight into the properties of confined water is important for our understanding of many geological and biological processes. Nanoporous silica has a wide range of technological applications because it is easy to tune the size of pores and their morphologies and to functionalize pore surfaces with a variety of molecular moieties. Nanoporous silica is used in catalysis, chromatography, anticorrosion coatings, desalination membranes, and as drug delivery vehicles. We use reactive molecular dynamics to study the structure and dynamics of nanoconfined water between 100 and 300 K

Assessment of inhalation exposures and potential health risks to the general population that resulted from the collapse of the World Trade Center towers.

PubMed

Lorber, Matthew; Gibb, Herman; Grant, Lester; Pinto, Joseph; Pleil, Joachim; Cleverly, David

2007-10-01

In the days following the collapse of the World Trade Center (WTC) towers on September 11, 2001 (9/11), the U.S. Environmental Protection Agency (EPA) initiated numerous air monitoring activities to better understand the ongoing impact of emissions from that disaster. Using these data, EPA conducted an inhalation exposure and human health risk assessment to the general population. This assessment does not address exposures and potential impacts that could have occurred to rescue workers, firefighters, and other site workers, nor does it address exposures that could have occurred in the indoor environment. Contaminants evaluated include particulate matter (PM), metals, polychlorinated biphenyls, dioxins, asbestos, volatile organic compounds, particle-bound polycyclic aromatic hydrocarbons, silica, and synthetic vitreous fibers (SVFs). This evaluation yielded three principal findings. (1) Persons exposed to extremely high levels of ambient PM and its components, SVFs, and other contaminants during the collapse of the WTC towers, and for several hours afterward, were likely to be at risk for acute and potentially chronic respiratory effects. (2) Available data suggest that contaminant concentrations within and near ground zero (GZ) remained significantly elevated above background levels for a few days after 9/11. Because only limited data on these critical few days were available, exposures and potential health impacts could not be evaluated with certainty for this time period. (3) Except for inhalation exposures that may have occurred on 9/11 and a few days afterward, the ambient air concentration data suggest that persons in the general population were unlikely to suffer short-term or long-term adverse health effects caused by inhalation exposures. While this analysis by EPA evaluated the potential for health impacts based on measured air concentrations, epidemiological studies conducted by organizations other than EPA have attempted to identify actual impacts. Such studies have identified respiratory effects in worker and general populations, and developmental effects in newborns whose mothers were near GZ on 9/11 or shortly thereafter. While researchers are not able to identify specific times and even exactly which contaminants are the cause of these effects, they have nonetheless concluded that exposure to WTC contaminants (and/or maternal stress, in the case of developmental effects) resulted in these effects, and have identified the time period including 9/11 itself and the days and few weeks afterward as a period of most concern based on high concentrations of key pollutants in the air and dust.

The effect of giant lateral collapses on magma pathways and the location of volcanism.

PubMed

Maccaferri, Francesco; Richter, Nicole; Walter, Thomas R

2017-10-23

Flank instability and lateral collapse are recurrent processes during the structural evolution of volcanic edifices, and they affect and are affected by magmatic activity. It is known that dyke intrusions have the potential to destabilise the flanks of a volcano, and that lateral collapses may change the style of volcanism and the arrangement of shallow dykes. However, the effect of a large lateral collapse on the location of a new eruptive centre remains unclear. Here, we use a numerical approach to simulate the pathways of magmatic intrusions underneath the volcanic edifice, after the stress redistribution resulting from a large lateral collapse. Our simulations are quantitatively validated against the observations at Fogo volcano, Cabo Verde. The results reveal that a lateral collapse can trigger a significant deflection of deep magma pathways in the crust, favouring the formation of a new eruptive centre within the collapse embayment. Our results have implications for the long-term evolution of intraplate volcanic ocean islands.

Four tails problems for dynamical collapse theories

NASA Astrophysics Data System (ADS)

McQueen, Kelvin J.

2015-02-01

The primary quantum mechanical equation of motion entails that measurements typically do not have determinate outcomes, but result in superpositions of all possible outcomes. Dynamical collapse theories (e.g. GRW) supplement this equation with a stochastic Gaussian collapse function, intended to collapse the superposition of outcomes into one outcome. But the Gaussian collapses are imperfect in a way that leaves the superpositions intact. This is the tails problem. There are several ways of making this problem more precise. But many authors dismiss the problem without considering the more severe formulations. Here I distinguish four distinct tails problems. The first (bare tails problem) and second (structured tails problem) exist in the literature. I argue that while the first is a pseudo-problem, the second has not been adequately addressed. The third (multiverse tails problem) reformulates the second to account for recently discovered dynamical consequences of collapse. Finally the fourth (tails problem dilemma) shows that solving the third by replacing the Gaussian with a non-Gaussian collapse function introduces new conflict with relativity theory.

Long gamma-ray bursts and core-collapse supernovae have different environments.

PubMed

Fruchter, A S; Levan, A J; Strolger, L; Vreeswijk, P M; Thorsett, S E; Bersier, D; Burud, I; Castro Cerón, J M; Castro-Tirado, A J; Conselice, C; Dahlen, T; Ferguson, H C; Fynbo, J P U; Garnavich, P M; Gibbons, R A; Gorosabel, J; Gull, T R; Hjorth, J; Holland, S T; Kouveliotou, C; Levay, Z; Livio, M; Metzger, M R; Nugent, P E; Petro, L; Pian, E; Rhoads, J E; Riess, A G; Sahu, K C; Smette, A; Tanvir, N R; Wijers, R A M J; Woosley, S E

2006-05-25

When massive stars exhaust their fuel, they collapse and often produce the extraordinarily bright explosions known as core-collapse supernovae. On occasion, this stellar collapse also powers an even more brilliant relativistic explosion known as a long-duration gamma-ray burst. One would then expect that these long gamma-ray bursts and core-collapse supernovae should be found in similar galactic environments. Here we show that this expectation is wrong. We find that the gamma-ray bursts are far more concentrated in the very brightest regions of their host galaxies than are the core-collapse supernovae. Furthermore, the host galaxies of the long gamma-ray bursts are significantly fainter and more irregular than the hosts of the core-collapse supernovae. Together these results suggest that long-duration gamma-ray bursts are associated with the most extremely massive stars and may be restricted to galaxies of limited chemical evolution. Our results directly imply that long gamma-ray bursts are relatively rare in galaxies such as our own Milky Way.

Dynamics of bubble collapse under vessel confinement in 2D hydrodynamic experiments

NASA Astrophysics Data System (ADS)

Shpuntova, Galina; Austin, Joanna

2013-11-01

One trauma mechanism in biomedical treatment techniques based on the application of cumulative pressure pulses generated either externally (as in shock-wave lithotripsy) or internally (by laser-induced plasma) is the collapse of voids. However, prediction of void-collapse driven tissue damage is a challenging problem, involving complex and dynamic thermomechanical processes in a heterogeneous material. We carry out a series of model experiments to investigate the hydrodynamic processes of voids collapsing under dynamic loading in configurations designed to model cavitation with vessel confinement. The baseline case of void collapse near a single interface is also examined. Thin sheets of tissue-surrogate polymer materials with varying acoustic impedance are used to create one or two parallel material interfaces near the void. Shadowgraph photography and two-color, single-frame particle image velocimetry quantify bubble collapse dynamics including jetting, interface dynamics and penetration, and the response of the surrounding material. Research supported by NSF Award #0954769, ``CAREER: Dynamics and damage of void collapse in biological materials under stress wave loading.''

CO 2-fluxing collapses metal mobility in magmatic vapour

DOE PAGES

van Hinsberg, V. J.; Berlo, K.; Migdisov, A. A.; ...

2016-05-18

Magmatic systems host many types of ore deposits, including world-class deposits of copper and gold. Magmas are commonly an important source of metals and ore-forming fluids in these systems. In many magmatic-hydrothermal systems, low-density aqueous fluids, or vapours, are significant metal carriers. Such vapours are water-dominated shallowly, but fluxing of CO 2-rich vapour exsolved from deeper magma is now recognised as ubiquitous during open-system magma degassing. Furthermore, we show that such CO 2-fluxing leads to a sharp drop in element solubility, up to a factor of 10,000 for Cu, and thereby provides a highly efficient, but as yet unrecognised mechanismmore » for metal deposition.« less

Astronomy at the dawn of the Renaissance. Proceedings. Symposium, Liège (Belgium), 23 - 24 Jul 1997, as part of the 20th International Congress of History of Science.

NASA Astrophysics Data System (ADS)

Mercier, R.

1998-05-01

Recent investigations of the astronomical work of the Byzantine Platonist George Gemistus Plethon provided the motivation, for Plethon's work encapsulated to many of the cross-currents flowing in astronomy in the early fifteenth century. At a time when the Byzantine world was in a state of collapse, and perhaps for that reason was more susceptible to foreign influence, Plethon drew not only on Ptolemy, but on the Greek Persian Syntaxis, and on al-Bāttani mediated through Hebrew. Both Plethon and his star pupil Cardinal Bessarion were great benefactors of scholarship, science, and philosophy in Renaissance Italy.

Collapse characteristics of hydroformed tubes

NASA Astrophysics Data System (ADS)

Kim, Young-Suk; Lee, Young-Moon; Kim, Cheol; Hwang, Sang-Moo

2002-07-01

Tube hydroforming technology (THF) has been extensively applied to auto-body structural members such as the engine cradle and side member in order to meet the urgent need for vehicle weight and cost reduction as well as high quality for collision accidents. In this paper, the mechanical properties for hydroformed tubes with various bulging strians under the plane strain mode are experimentally investigated. Axial compression tests for hydroformed tubes are performed to investigate the collapse load and collapse absorption capacity through the collapse load-displacement curves. Moreover, the collapse absorption capacities are compared and discussed among as-received, hydroformed, and press formed tubes. Results demonstrate that the hydroformed tubes show higher collapse absorption capability in comparison with the as-received tube and the press formed tube because of its high yield strength due to strain hardening.

Spherical collapse in chameleon models

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

Brax, Ph.; Rosenfeld, R.; Steer, D.A., E-mail: brax@spht.saclay.cea.fr, E-mail: rosenfel@ift.unesp.br, E-mail: daniele.steer@apc.univ-paris7.fr

2010-08-01

We study the gravitational collapse of an overdensity of nonrelativistic matter under the action of gravity and a chameleon scalar field. We show that the spherical collapse model is modified by the presence of a chameleon field. In particular, we find that even though the chameleon effects can be potentially large at small scales, for a large enough initial size of the inhomogeneity the collapsing region possesses a thin shell that shields the modification of gravity induced by the chameleon field, recovering the standard gravity results. We analyse the behaviour of a collapsing shell in a cosmological setting in themore » presence of a thin shell and find that, in contrast to the usual case, the critical density for collapse in principle depends on the initial comoving size of the inhomogeneity.« less

Variation of the temperature coefficient of collapse field in bismuth-based bubble garnets

NASA Technical Reports Server (NTRS)

Fratello, V. J.; Pierce, R. D.; Brandle, C. D.

1985-01-01

An approximation to the collapse-field formula is used to show its dependence on magnetization and wall energy and the effect of additions of Gd, Sm, and Eu on 1-micron Bi:YIG bubble materials. The collapse field, magnetization, and wall energy are fitted to quadratic functions of temperature from -50 to 150 C. It is shown that the addition of the various classes of rare earths reduces the temperature derivative of the collapse field in Bi:YIG. Gd influences the collapse field through the magnetization, Sm affects it through the domain wall energy, and Eu does both. The singular magnetic properties of Eu result in the most nearly constant temperature dependence of the collapse field and the best match to a barium-ferrite bias magnite.

Protostellar collapse in a self-gravitating sheet

NASA Technical Reports Server (NTRS)

Hartmann, Lee; Boss, Alan; Calvet, Nuria; Whitney, Barbara

1994-01-01

We present preliminary calculations of protostellar cloud collapse starting from an isothermal, self-gravitating gaseous layer in hydrostatic equilibrium. This gravitationally unstable layer collapses into a flattened or toroidal density distribution, even in the absence of rotation or magnetic fields. We suggest that the flat infalling envelope recently observed in HL Tau by Hayashi et al.is the result of collapse from an initially nonspherical layer. We also speculate that the later evolution of such a flattened, collapsing envelope can produce a structure similar to the 'flared disk' invoked by Kenyon and Hartmann to explain the infrared excesses of many T Tauri stars.

Atomistic modeling of shock-induced void collapse in copper

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

Davila, L P; Erhart, P; Bringa, E M

2005-03-09

Nonequilibrium molecular dynamics (MD) simulations show that shock-induced void collapse in copper occurs by emission of shear loops. These loops carry away the vacancies which comprise the void. The growth of the loops continues even after they collide and form sessile junctions, creating a hardened region around the collapsing void. The scenario seen in our simulations differs from current models that assume that prismatic loop emission is responsible for void collapse. We propose a new dislocation-based model that gives excellent agreement with the stress threshold found in the MD simulations for void collapse as a function of void radius.

Beliefs in an Unjust World: Mediating Ethnicity-Related Stressors and Psychological Functioning.

PubMed

Liang, Christopher T H; Molenaar, Carin M

2016-06-01

Racism is negatively associated with health. Explorations of cognitive reactions, such as beliefs in an unjust world (BUW), are needed to understand the associations between both perceived discrimination and own-group conformity pressures (OGCPS) and reduced psychological well-being. With a sample of 215 ethnic minority individuals, this study used structural equation modeling to explore BUW's mediating role between the two aforementioned forms of ethnicity-related stressors (ERS), anger rumination, and negative affect. ERS were directly positively associated with BUW, anger rumination, and negative affect. BUW were directly and positively associated with both anger rumination and negative affect. Finally, BUW significantly mediated the direct relationships between both ethnicity-related stressors and anger rumination and negative affect. Although addressing racism and OGCPS at a systemic level (e.g., policy, prejudice prevention) is needed to reduce ERS, these findings suggest that BUW is one point of possible clinical intervention for individuals who have experienced these stressors. © 2016 Wiley Periodicals, Inc.

No Robust Association between Static Markers of Testosterone and Facets of Socio-Economic Decision Making

PubMed Central

Kaltwasser, Laura; Mikac, Una; Buško, Vesna; Hildebrandt, Andrea

2017-01-01

Digit ratio (2D:4D) and facial width-to-height ratio (WHR) are supposedly static indicators of testosterone exposition during prenatal and pubertal lifetime, respectively. Both measures have been linked to aggressive and assertive behavior in laboratory economic games, as well as in real world scenarios. Most of the research—often limited to male subjects—considers the associations between these behaviors, traits, and hormonal markers separately for 2D:4D and WHR. Reported associations are weak and volatile. In the present study we had independent raters assess 2D:4D and WHR in a sample of N = 175 participants who played the ultimatum game (UG). Respondent behavior in UG captures the tendency to reject unfair offers (negative reciprocity). If unfair UG offers are seen as provocations, then individuals with stronger testosterone exposition may be more prone to reject such offers. Economists argue that negative reciprocity reflects altruistic punishment, since the rejecting individual is sacrificing own resources. However, recent studies suggest that self-interest, in terms of status defense plays a substantial role in decisions to reject unfair offers. We also assessed social preferences by social value orientation and assertiveness via self-report. By applying structural equation modeling we estimated the latent level association of 2D:4D and WHR with negative reciprocity, assertiveness and prosociality in both sexes. Results revealed no robust association between any of the trait measures and hormonal markers. The measures of 2D:4D and WHR were not related with each other. Multigroup models based on sex suggested invariance of factor loadings allowing to compare hormone-behavior relationships of females and males. Only when collapsing across sex greater WHR was weakly associated with assertiveness, suggesting that individuals with wider faces tend to express greater status defense. Only the right hand 2D:4D was weakly associated with prosocial behavior, indicating that individuals with lower prenatal testosterone exposure are more cooperative. Rejection behavior in UG was not related with 2D:4D nor WHR in any of the models. There were also no curvilinear associations between 2D:4D and prosociality as theorized in the literature. Our results suggest that previous studies over-estimated the role of static markers of testosterone in accounting for aggression and competition behavior in males. PMID:29326567

No Robust Association between Static Markers of Testosterone and Facets of Socio-Economic Decision Making.

PubMed

Kaltwasser, Laura; Mikac, Una; Buško, Vesna; Hildebrandt, Andrea

2017-01-01

Digit ratio (2D:4D) and facial width-to-height ratio (WHR) are supposedly static indicators of testosterone exposition during prenatal and pubertal lifetime, respectively. Both measures have been linked to aggressive and assertive behavior in laboratory economic games, as well as in real world scenarios. Most of the research-often limited to male subjects-considers the associations between these behaviors, traits, and hormonal markers separately for 2D:4D and WHR. Reported associations are weak and volatile. In the present study we had independent raters assess 2D:4D and WHR in a sample of N = 175 participants who played the ultimatum game (UG). Respondent behavior in UG captures the tendency to reject unfair offers (negative reciprocity). If unfair UG offers are seen as provocations, then individuals with stronger testosterone exposition may be more prone to reject such offers. Economists argue that negative reciprocity reflects altruistic punishment, since the rejecting individual is sacrificing own resources. However, recent studies suggest that self-interest, in terms of status defense plays a substantial role in decisions to reject unfair offers. We also assessed social preferences by social value orientation and assertiveness via self-report. By applying structural equation modeling we estimated the latent level association of 2D:4D and WHR with negative reciprocity, assertiveness and prosociality in both sexes. Results revealed no robust association between any of the trait measures and hormonal markers. The measures of 2D:4D and WHR were not related with each other. Multigroup models based on sex suggested invariance of factor loadings allowing to compare hormone-behavior relationships of females and males. Only when collapsing across sex greater WHR was weakly associated with assertiveness, suggesting that individuals with wider faces tend to express greater status defense. Only the right hand 2D:4D was weakly associated with prosocial behavior, indicating that individuals with lower prenatal testosterone exposure are more cooperative. Rejection behavior in UG was not related with 2D:4D nor WHR in any of the models. There were also no curvilinear associations between 2D:4D and prosociality as theorized in the literature. Our results suggest that previous studies over-estimated the role of static markers of testosterone in accounting for aggression and competition behavior in males.

Creating a Global Building Inventory for Earthquake Loss Assessment and Risk Management

USGS Publications Warehouse

Jaiswal, Kishor; Wald, David J.

2008-01-01

Earthquakes have claimed approximately 8 million lives over the last 2,000 years (Dunbar, Lockridge and others, 1992) and fatality rates are likely to continue to rise with increased population and urbanizations of global settlements especially in developing countries. More than 75% of earthquake-related human casualties are caused by the collapse of buildings or structures (Coburn and Spence, 2002). It is disheartening to note that large fractions of the world's population still reside in informal, poorly-constructed & non-engineered dwellings which have high susceptibility to collapse during earthquakes. Moreover, with increasing urbanization half of world's population now lives in urban areas (United Nations, 2001), and half of these urban centers are located in earthquake-prone regions (Bilham, 2004). The poor performance of most building stocks during earthquakes remains a primary societal concern. However, despite this dark history and bleaker future trends, there are no comprehensive global building inventories of sufficient quality and coverage to adequately address and characterize future earthquake losses. Such an inventory is vital both for earthquake loss mitigation and for earthquake disaster response purposes. While the latter purpose is the motivation of this work, we hope that the global building inventory database described herein will find widespread use for other mitigation efforts as well. For a real-time earthquake impact alert system, such as U.S. Geological Survey's (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER), (Wald, Earle and others, 2006), we seek to rapidly evaluate potential casualties associated with earthquake ground shaking for any region of the world. The casualty estimation is based primarily on (1) rapid estimation of the ground shaking hazard, (2) aggregating the population exposure within different building types, and (3) estimating the casualties from the collapse of vulnerable buildings. Thus, the contribution of building stock, its relative vulnerability, and distribution are vital components for determining the extent of casualties during an earthquake. It is evident from large deadly historical earthquakes that the distribution of vulnerable structures and their occupancy level during an earthquake control the severity of human losses. For example, though the number of strong earthquakes in California is comparable to that of Iran, the total earthquake-related casualties in California during the last 100 years are dramatically lower than the casualties from several individual Iranian earthquakes. The relatively low casualties count in California is attributed mainly to the fact that more than 90 percent of the building stock in California is made of wood and is designed to withstand moderate to large earthquakes (Kircher, Seligson and others, 2006). In contrast, the 80 percent adobe and or non-engineered masonry building stock with poor lateral load resisting systems in Iran succumbs even for moderate levels of ground shaking. Consequently, the heavy death toll for the 2003 Bam, Iran earthquake, which claimed 31,828 lives (Ghafory-Ashtiany and Mousavi, 2005), is directly attributable to such poorly resistant construction, and future events will produce comparable losses unless practices change. Similarly, multistory, precast-concrete framed buildings caused heavy casualties in the 1988 Spitak, Armenia earthquake (Bertero, 1989); weaker masonry and reinforced-concrete framed construction designed for gravity loads with soft first stories dominated losses in the Bhuj, India earthquake of 2001 (Madabhushi and Haigh, 2005); and adobe and weak masonry dwellings in Peru controlled the death toll in the Peru earthquake of 2007 (Taucer, J. and others, 2007). Spence (2007) after conducting a brief survey of most lethal earthquakes since 1960 found that building collapses remains a major cause of earthquake mortality and unreinforced masonry buildings are one of the mos

Negation in context: Evidence from the visual world paradigm.

PubMed

Orenes, Isabel; Moxey, Linda; Scheepers, Christoph; Santamaría, Carlos

2016-01-01

Literature assumes that negation is more difficult to understand than affirmation, but this might depend on the pragmatic context. The goal of this paper is to show that pragmatic knowledge modulates the unfolding processing of negation due to the previous activation of the negated situation. To test this, we used the visual world paradigm. In this task, we presented affirmative (e.g., her dad was rich) and negative sentences (e.g., her dad was not poor) while viewing two images of the affirmed and denied entities. The critical sentence in each item was preceded by one of three types of contexts: an inconsistent context (e.g., She supposed that her dad had little savings) that activates the negated situation (a poor man), a consistent context (e.g., She supposed that her dad had enough savings) that activates the actual situation (a rich man), or a neutral context (e.g., her dad lived on the other side of town) that activates neither of the two models previously suggested. The results corroborated our hypothesis. Pragmatics is implicated in the unfolding processing of negation. We found an increase in fixations on the target compared to the baseline for negative sentences at 800 ms in the neutral context, 600 ms in the inconsistent context, and 1450 ms in the consistent context. Thus, when the negated situation has been previously introduced via an inconsistent context, negation is facilitated.

Model for quantum effects in stellar collapse

NASA Astrophysics Data System (ADS)

Arderucio-Costa, Bruno; Unruh, William G.

2018-01-01

We present a simple model for stellar collapse and evaluate the quantum mechanical stress-energy tensor to argue that quantum effects do not play an important role for the collapse of astrophysical objects.

Reversible collapse of insoluble monolayers: new insights on the influence of the anisotropic line tension of the domain.

PubMed

González-Delgado, Antonio M; Pérez-Morales, Marta; Giner-Casares, Juan J; Muñoz, Eulogia; Martín-Romero, María T; Camacho, Luis

2009-10-08

In this paper, we study the collapse of a mixed insoluble monolayer formed by a cationic matrix, dioctadecyl-dimethylammonium bromide (DOMA), and a tetra-anionic porphyrin, tetrakis(4-sulfonatophenyl)porphyrin (TSPP), in a molar ratio TSPP/DOMA = 1:4. During the collapse of this system, we visualized the formation of circular domains consisting exclusively of trilayer, although the domains coalescence was not observed. The coexistence of trilayer and monolayer at the final step of the collapse cannot be interpreted exclusively in terms of a thermodynamic phase equilibrium, intervening as an additional factor the anisotropic line tension of the domain. A high line tension implies a high resistance to the domain deformation, and the anisotropy of the line tension implies the lack of coalescence between these domains, which has been experimentally observed by Brewster angle microscopy for us. Under these circumstances, the domains of collapsed material could enclose monolayer regions where the local surface pressure drops thus stopping the collapse process. The collapse of the TSPP/DOMA system is reversible, that is, the return of the three-dimensional material to the monolayer fits into a simple kinetics according to the nucleation-growth-collision theory. As for the collapse, the reverse process is also affected by the line tension of the domains. This paper relates the high line tension and the anisotropic line tension of a given domains with the reversible nature of the collapse process.

Numerical investigation of trichel pulse of negative corona discharge in N2-O2 mixture

NASA Astrophysics Data System (ADS)

Xia, Qing; Zhang, Yu; Jiang, Zhaorui; Wang, Ronggang; Ouyang, Jiting

2017-12-01

Trichel pulse of negative corona discharge in atmospheric air is investigated numerically using a 2D fluid model. The model consists of a hyperbolic cathode tip and a plane anode, and considers 11 kinds of particles and the most important interactions among them. The spatio-temporal evolution of charged species and the electric field are evaluated during the pulse process. During the pulse rising edge, the positive ions accumulate ahead of the tip forming the temporal cathode sheath, significantly enhancing the local field. In the pulse decay edge, the temporal sheath collapses and the discharge falls back to a low-current mode. In the pulse interval, the discharge does not cease but sustains weakly until the next pulse. The location of the temporal sheath is independent of the averaged value during the Trichel pulse regime and also the same with that in a normal glow regime, which determines a nearly constant pulse rising time at given configurations. However, a smaller tip radius will lead to their decrease. The effect of negative ions on the pulse process is studied by adjusting the attachment rates. It indicates that the negative ions are actually not necessary in the Trichel pulse process, but will influence the pulse waveform significantly.

Spacetime Curvature and Higgs Stability after Inflation.

PubMed

Herranen, M; Markkanen, T; Nurmi, S; Rajantie, A

2015-12-11

We investigate the dynamics of the Higgs field at the end of inflation in the minimal scenario consisting of an inflaton field coupled to the standard model only through the nonminimal gravitational coupling ξ of the Higgs field. Such a coupling is required by renormalization of the standard model in curved space, and in the current scenario also by vacuum stability during high-scale inflation. We find that for ξ≳1, rapidly changing spacetime curvature at the end of inflation leads to significant production of Higgs particles, potentially triggering a transition to a negative-energy Planck scale vacuum state and causing an immediate collapse of the Universe.

Proton Gradient-Driven Nickel Uptake by Vacuolar Membrane Vesicles of Saccharomyces cerevisiae

PubMed Central

Nishimura, Ken; Igarashi, Kazuei; Kakinuma, Yoshimi

1998-01-01

A vacuolar H+-ATPase-negative mutant of Saccharomyces cerevisiae was highly sensitive to nickel ion. Accumulation of nickel ion in the cells of this mutant of less than 60% of the value for the parent strain arrested growth, suggesting a role for this ATPase in sequestering nickel ion into vacuoles. An artificially imposed pH gradient (interior acid) induced transient nickel ion uptake by vacuolar membrane vesicles, which was inhibited by collapse of the pH difference but not of the membrane potential. Nickel ion transport into vacuoles in a pH gradient-dependent manner is thus important for its detoxification in yeast. PMID:9537401

Vacuum-assisted closure as a surgical assistant in life-threatening necrotizing fasciitis in children

PubMed Central

Al-Subhi, FS; Zuker, RM; Cole, WG

2010-01-01

Necrotizing fasciitis is a severe soft tissue infection that can involve skin, subcutaneous fat, fascia and muscle. It can result in devastating sequelae including tissue necrosis, sepsis, toxic shock syndrome, cardiopulmonary collapse and death. To control rapidly spreading necrosis, early diagnosis and aggressive surgical treatment with extensive radical debridement of the affected areas is necessary, as well as systemic administration of broad-spectrum antimicrobials and, very often, intensive care support. The subatmospheric negative pressure dressing has been previously used in acute and complex wounds management. The concept of using vacuum-assisted closure dressing as another management component is presented in the current article. PMID:22131841

The Kavar(D) dominant female-sterile mutations of Drosophila reveal a role for the maternally provided alpha-tubulin4 isoform in cleavage spindle maintenance and elongation.

PubMed

Venkei, Zsolt; Szabad, János

2005-06-01

The dominant-negative female-sterile Kavar(D) mutations and their revertant kavar(r) alleles identify the alphaTubulin67C gene of Drosophila melanogaster, which codes for the maternally provided alpha-tubulin(4) isoform. The mutations result in the formation of monopolar, collapsed spindles (each with two nearby centrosomes, a tassel of microtubules and overcondensed chromosomes), thus revealing a novel function for alpha-tubulin(4) in spindle maintenance and elongation. Molecular features of the two Kavar(D) alleles and a kavar(null) allele are described and models for their actions are discussed.

The Brittleness and Chemical Stability of Optimized Geopolymer Composites

PubMed Central

Steinerova, Michaela; Matulova, Lenka; Vermach, Pavel; Kotas, Jindrich

2017-01-01

Geopolymers are known as high strength and durable construction materials but have a brittle fracture. In practice, this results in a sudden collapse at ultimate load, without any chance of preventing the breakdown of parts or of withstanding the stress for some time. Glass fiber usage as a total anisotropic shape acting as a compact structure component should hinder the fracture mechanism. The optimized compositions in this study led to a significant reinforcement, especially in the case of flexural strength, but also in terms of the compressive strength and notch toughness. The positive and negative influence of the fibers on the complex composite properties provided chemical stability. PMID:28772756

The Brittleness and Chemical Stability of Optimized Geopolymer Composites.

PubMed

Steinerova, Michaela; Matulova, Lenka; Vermach, Pavel; Kotas, Jindrich

2017-04-09

Geopolymers are known as high strength and durable construction materials but have a brittle fracture. In practice, this results in a sudden collapse at ultimate load, without any chance of preventing the breakdown of parts or of withstanding the stress for some time. Glass fiber usage as a total anisotropic shape acting as a compact structure component should hinder the fracture mechanism. The optimized compositions in this study led to a significant reinforcement, especially in the case of flexural strength, but also in terms of the compressive strength and notch toughness. The positive and negative influence of the fibers on the complex composite properties provided chemical stability.

Void collapse under distributed dynamic loading near material interfaces

NASA Astrophysics Data System (ADS)

Shpuntova, Galina; Austin, Joanna

2012-11-01

Collapsing voids cause significant damage in diverse applications from biomedicine to underwater propulsion to explosives. While shock-induced void collapse has been studied extensively, less attention has been devoted to stress wave loading, which will occur instead if there are mechanisms for wave attenuation or if the impact velocity is relatively low. A set of dynamic experiments was carried out in a model experimental setup to investigate the effect of acoustic heterogeneities in the surrounding medium on void collapse. Two tissue-surrogate polymer materials of varying acoustic properties were used to create flowfield geometries involving a boundary and a void. A stress wave, generated by projectile impact, triggered void collapse in the gelatinous polymer medium. When the length scales of features in the flow field were on the same order of magnitude as the stress wave length scale, the presence of the boundary was found to affect the void collapse process relative to collapse in the absence of a boundary. This effect was quantified for a range of geometries and impact conditions using a two-color, single-frame particle image velocimetry technique. Research supported by NSF Award #0954769, ``CAREER: Dynamics and damage of void collapse in biological materials under stress wave loading'' with Prof. Henning Winter as Program Manager.

An assessment on the use of bivariate, multivariate and soft computing techniques for collapse susceptibility in GIS environ

NASA Astrophysics Data System (ADS)

Yilmaz, Işik; Marschalko, Marian; Bednarik, Martin

2013-04-01

The paper presented herein compares and discusses the use of bivariate, multivariate and soft computing techniques for collapse susceptibility modelling. Conditional probability (CP), logistic regression (LR) and artificial neural networks (ANN) models representing the bivariate, multivariate and soft computing techniques were used in GIS based collapse susceptibility mapping in an area from Sivas basin (Turkey). Collapse-related factors, directly or indirectly related to the causes of collapse occurrence, such as distance from faults, slope angle and aspect, topographical elevation, distance from drainage, topographic wetness index (TWI), stream power index (SPI), Normalized Difference Vegetation Index (NDVI) by means of vegetation cover, distance from roads and settlements were used in the collapse susceptibility analyses. In the last stage of the analyses, collapse susceptibility maps were produced from the models, and they were then compared by means of their validations. However, Area Under Curve (AUC) values obtained from all three models showed that the map obtained from soft computing (ANN) model looks like more accurate than the other models, accuracies of all three models can be evaluated relatively similar. The results also showed that the conditional probability is an essential method in preparation of collapse susceptibility map and highly compatible with GIS operating features.

Words Apart, Worlds Apart: Peritexts from Islamized Translations of World Classics in Children's Literature

ERIC Educational Resources Information Center

Kansu-Yetkiner, Neslihan

2014-01-01

This article examines the political polarization between Republicans and Islamists in Turkey as reflected in the peritexts of recent translations of world children's literature. This is reflected in terms of van Dijk's notions of an us vs them binarism, where a positive in-group is opposed to a negative out-group representation. In this way, the…

Identification and behavior of collapsible soils : [technical summary].

DOT National Transportation Integrated Search

2011-01-01

Collapsible soils are susceptible to large volumetric strains when they become saturated. Numerous soil types : fall in the general category of collapsible soils, including : loess, a well-known aeolian deposit, present throughout : most of Indiana. ...

Monitoring crater-wall collapse at active volcanoes: a study of the 12 January 2013 event at Stromboli

NASA Astrophysics Data System (ADS)

Calvari, Sonia; Intrieri, Emanuele; Di Traglia, Federico; Bonaccorso, Alessandro; Casagli, Nicola; Cristaldi, Antonio

2016-05-01

Crater-wall collapses are fairly frequent at active volcanoes and they are normally studied through the analysis of their deposits. In this paper, we present an analysis of the 12 January 2013 crater-wall collapse occurring at Stromboli volcano, investigated by means of a monitoring network comprising visible and infrared webcams and a Ground-Based Interferometric Synthetic Aperture Radar. The network revealed the triggering mechanisms of the collapse, which are comparable to the events that heralded the previous effusive eruptions in 1985, 2002, 2007 and 2014. The collapse occurred during a period of inflation of the summit cone and was preceded by increasing explosive activity and the enlargement of the crater. Weakness of the crater wall, increasing magmastatic pressure within the upper conduit induced by ascending magma and mechanical erosion caused by vent opening at the base of the crater wall and by lava fingering, are considered responsible for triggering the collapse on 12 January 2013 at Stromboli. We suggest that the combination of these factors might be a general mechanism to generate crater-wall collapse at active volcanoes.

Experimental study of shock-driven cavity collapse with a single-stage gas gun driver

NASA Astrophysics Data System (ADS)

Anderson, Phillip; Betney, Matthew; Doyle, Hugo; Hawker, Nicholas; Roy, Ronald

2014-10-01

This paper explores experimental studies of shock-driven cavity collapse using a single-stage gas gun. Shocks of up to 1 GPa are generated in a hydrogel with the impact of a planar-faced projectile (50 mm dia.). Within the hydrogel, a pre-formed cavity (5 mm dia.) is cast, which is collapsed by the interaction with the shockwave. The basic collapse process involves the formation of a high-speed transverse jet and then a second collapse phase driven from jet impact. Single-shot multi-frame schlieren imaging is used to show the position and timing of optical emission in relation to the collapse hydrodynamics. Further, temporally and spectrally-resolved measurements of the optical emission are made through simultaneous use of multiple band-passed PMTs and an integrating spectrometer. This reveals three distinct pulses of emission possessing different frequency content. The first corresponds to the trapping of gas during jet impact; the second and third correspond to the further inertial collapse of the now toroidal cavity. Plasma models are used to provide the first indication of the temperature of these inertially confined plasmas.

Volcano collapse promoted by hydrothermal alteration and edifice shape, Mount Rainier, Washington

USGS Publications Warehouse

Reid, M.E.; Sisson, T.W.; Brien, D.L.

2001-01-01

Catastrophic collapses of steep volcano flanks threaten many populated regions, and understanding factors that promote collapse could save lives and property. Large collapses of hydrothermally altered parts of Mount Rainier have generated far-traveled debris flows; future flows would threaten densely populated parts of the Puget Sound region. We evaluate edifice collapse hazards at Mount Rainier using a new three-dimensional slope stability method incorporating detailed geologic mapping and subsurface geophysical imaging to determine distributions of strong (fresh) and weak (altered) rock. Quantitative three-dimensional slope stability calculations reveal that sizeable flank collapse (>0.1 km3) is promoted by voluminous, weak, hydrothermally altered rock situated high on steep slopes. These conditions exist only on Mount Rainier's upper west slope, consistent with the Holocene debris-flow history. Widespread alteration on lower flanks or concealed in regions of gentle slope high on the edifice does not greatly facilitate collapse. Our quantitative stability assessment method can also provide useful hazard predictions using reconnaissance geologic information and is a potentially rapid and inexpensive new tool for aiding volcano hazard assessments.

Does Pressure Accentuate General Relativistic Gravitational Collapse and Formation of Trapped Surfaces?

NASA Astrophysics Data System (ADS)

Mitra, Abhas

2013-04-01

It is widely believed that though pressure resists gravitational collapse in Newtonian gravity, it aids the same in general relativity (GR) so that GR collapse should eventually be similar to the monotonous free fall case. But we show that, even in the context of radiationless adiabatic collapse of a perfect fluid, pressure tends to resist GR collapse in a manner which is more pronounced than the corresponding Newtonian case and formation of trapped surfaces is inhibited. In fact there are many works which show such collapse to rebound or become oscillatory implying a tug of war between attractive gravity and repulsive pressure gradient. Furthermore, for an imperfect fluid, the resistive effect of pressure could be significant due to likely dramatic increase of tangential pressure beyond the "photon sphere." Indeed, with inclusion of tangential pressure, in principle, there can be static objects with surface gravitational redshift z → ∞. Therefore, pressure can certainly oppose gravitational contraction in GR in a significant manner in contradiction to the idea of Roger Penrose that GR continued collapse must be unstoppable.

Early warning signals of Atlantic Meridional Overturning Circulation collapse in a fully coupled climate model

NASA Astrophysics Data System (ADS)

Boulton, Chris A.; Allison, Lesley C.; Lenton, Timothy M.

2014-12-01

The Atlantic Meridional Overturning Circulation (AMOC) exhibits two stable states in models of varying complexity. Shifts between alternative AMOC states are thought to have played a role in past abrupt climate changes, but the proximity of the climate system to a threshold for future AMOC collapse is unknown. Generic early warning signals of critical slowing down before AMOC collapse have been found in climate models of low and intermediate complexity. Here we show that early warning signals of AMOC collapse are present in a fully coupled atmosphere-ocean general circulation model, subject to a freshwater hosing experiment. The statistical significance of signals of increasing lag-1 autocorrelation and variance vary with latitude. They give up to 250 years warning before AMOC collapse, after ~550 years of monitoring. Future work is needed to clarify suggested dynamical mechanisms driving critical slowing down as the AMOC collapse is approached.

Early warning signals of Atlantic Meridional Overturning Circulation collapse in a fully coupled climate model

PubMed Central

Boulton, Chris A.; Allison, Lesley C.; Lenton, Timothy M.

2014-01-01

The Atlantic Meridional Overturning Circulation (AMOC) exhibits two stable states in models of varying complexity. Shifts between alternative AMOC states are thought to have played a role in past abrupt climate changes, but the proximity of the climate system to a threshold for future AMOC collapse is unknown. Generic early warning signals of critical slowing down before AMOC collapse have been found in climate models of low and intermediate complexity. Here we show that early warning signals of AMOC collapse are present in a fully coupled atmosphere-ocean general circulation model, subject to a freshwater hosing experiment. The statistical significance of signals of increasing lag-1 autocorrelation and variance vary with latitude. They give up to 250 years warning before AMOC collapse, after ~550 years of monitoring. Future work is needed to clarify suggested dynamical mechanisms driving critical slowing down as the AMOC collapse is approached. PMID:25482065

Early warning signals of Atlantic Meridional Overturning Circulation collapse in a fully coupled climate model.

PubMed

Boulton, Chris A; Allison, Lesley C; Lenton, Timothy M

2014-12-08

The Atlantic Meridional Overturning Circulation (AMOC) exhibits two stable states in models of varying complexity. Shifts between alternative AMOC states are thought to have played a role in past abrupt climate changes, but the proximity of the climate system to a threshold for future AMOC collapse is unknown. Generic early warning signals of critical slowing down before AMOC collapse have been found in climate models of low and intermediate complexity. Here we show that early warning signals of AMOC collapse are present in a fully coupled atmosphere-ocean general circulation model, subject to a freshwater hosing experiment. The statistical significance of signals of increasing lag-1 autocorrelation and variance vary with latitude. They give up to 250 years warning before AMOC collapse, after ~550 years of monitoring. Future work is needed to clarify suggested dynamical mechanisms driving critical slowing down as the AMOC collapse is approached.

Wetting dynamics of a collapsing fluid hole

NASA Astrophysics Data System (ADS)

Bostwick, J. B.; Dijksman, J. A.; Shearer, M.

2017-01-01

The collapse dynamics of an axisymmetric fluid cavity that wets the bottom of a rotating bucket bound by vertical sidewalls are studied. Lubrication theory is applied to the governing field equations for the thin film to yield an evolution equation that captures the effect of capillary, gravitational, and centrifugal forces on this converging flow. The focus is on the quasistatic spreading regime, whereby contact-line motion is governed by a constitutive law relating the contact-angle to the contact-line speed. Surface tension forces dominate the collapse dynamics for small holes with the collapse time appearing as a power law whose exponent compares favorably to experiments in the literature. Gravity accelerates the collapse process. Volume dependence is predicted and compared with experiment. Centrifugal forces slow the collapse process and lead to complex dynamics characterized by stalled spreading behavior that separates the large and small hole asymptotic regimes.

Gradual caldera collapse at Bárdarbunga volcano, Iceland, regulated by lateral magma outflow.

PubMed

Gudmundsson, Magnús T; Jónsdóttir, Kristín; Hooper, Andrew; Holohan, Eoghan P; Halldórsson, Sæmundur A; Ófeigsson, Benedikt G; Cesca, Simone; Vogfjörd, Kristín S; Sigmundsson, Freysteinn; Högnadóttir, Thórdís; Einarsson, Páll; Sigmarsson, Olgeir; Jarosch, Alexander H; Jónasson, Kristján; Magnússon, Eyjólfur; Hreinsdóttir, Sigrún; Bagnardi, Marco; Parks, Michelle M; Hjörleifsdóttir, Vala; Pálsson, Finnur; Walter, Thomas R; Schöpfer, Martin P J; Heimann, Sebastian; Reynolds, Hannah I; Dumont, Stéphanie; Bali, Eniko; Gudfinnsson, Gudmundur H; Dahm, Torsten; Roberts, Matthew J; Hensch, Martin; Belart, Joaquín M C; Spaans, Karsten; Jakobsson, Sigurdur; Gudmundsson, Gunnar B; Fridriksdóttir, Hildur M; Drouin, Vincent; Dürig, Tobias; Aðalgeirsdóttir, Guðfinna; Riishuus, Morten S; Pedersen, Gro B M; van Boeckel, Tayo; Oddsson, Björn; Pfeffer, Melissa A; Barsotti, Sara; Bergsson, Baldur; Donovan, Amy; Burton, Mike R; Aiuppa, Alessandro

2016-07-15

Large volcanic eruptions on Earth commonly occur with a collapse of the roof of a crustal magma reservoir, forming a caldera. Only a few such collapses occur per century, and the lack of detailed observations has obscured insight into the mechanical interplay between collapse and eruption. We use multiparameter geophysical and geochemical data to show that the 110-square-kilometer and 65-meter-deep collapse of Bárdarbunga caldera in 2014-2015 was initiated through withdrawal of magma, and lateral migration through a 48-kilometers-long dike, from a 12-kilometers deep reservoir. Interaction between the pressure exerted by the subsiding reservoir roof and the physical properties of the subsurface flow path explain the gradual, near-exponential decline of both collapse rate and the intensity of the 180-day-long eruption. Copyright © 2016, American Association for the Advancement of Science.

Earth's Volcanoes and their Eruptions; the 3rd edition of the Smithsonian Institution's Volcanoes of the World

NASA Astrophysics Data System (ADS)

Siebert, L.; Simkin, T.; Kimberly, P.

2010-12-01

The 3rd edition of the Smithsonian Institution’s Volcanoes of the World incorporates data on the world’s volcanoes and their eruptions compiled since 1968 by the Institution’s Global Volcanism Program (GVP). Published this Fall jointly by the Smithsonian and the University of California Press, it supplements data from the 1994 2nd edition and includes new data on the number of people living in proximity to volcanoes, the dominant rock lithologies at each volcano, Holocene caldera-forming eruptions, and preliminary lists of Pleistocene volcanoes and large-volume Pleistocene eruptions. The 3rd edition contains data on nearly 1550 volcanoes of known or possible Holocene age, including chronologies, characteristics, and magnitudes for >10,400 Holocene eruptions. The standard 20 eruptive characteristics of the IAVCEI volcano catalog series have been modified to include dated vertical edifice collapse events due to magma chamber evacuation following large-volume explosive eruptions or mafic lava effusion, and lateral sector collapse. Data from previous editions of Volcanoes of the World are also supplemented by listings of up to the 5 most dominant lithologies at each volcano, along with data on population living within 5, 10, 30, and 100 km radii of each volcano or volcanic field. Population data indicate that the most populated regions also contain the most frequently active volcanoes. Eruption data document lava and tephra volumes and Volcanic Explosivity Index (VEI) assignments for >7800 eruptions. Interpretation of VRF data has led to documentation of global eruption rates and the power law relationship between magnitude and frequency of volcanic eruptions. Data with volcanic hazards implications include those on fatalities and evacuations and the rate at which eruptions reach their climax. In recognition of the hazards implications of potential resumption of activity at pre-Holocene volcanoes, the 3rd edition includes very preliminary lists of Pleistocene volcanoes and large-volume Pleistocene eruptions, the latter in collaboration with the VOGRIPA project of Steve Sparks and colleagues. The GVP volcano and eruption data derive both from the retrospective perspective of the volcanological and other literature and documentation of contemporary eruptions and volcanic unrest in the Smithsonian’s monthly bulletin and Weekly Volcanic Activity Reports compiled since 2000 in collaboration with the USGS.

Collapsable seal member

DOEpatents

Sherrell, Dennis L.

1990-01-01

A hollow, collapsable seal member normally disposed in a natural expanded state offering fail-safe pressure sealing against a seating surface and adapted to be evacuated by a vacuum force for collapsing the seal member to disengage the same from said seating surface.

Collapsable seal member

DOEpatents

Sherrell, D.L.

1983-12-08

A hollow, collapsable seal member normally disposed in a natural expanded state offering fail-safe pressure sealing against a seating surface and adapted to be evacuated by a vacuum force for collapsing the seal member to disengage the same from said seating surface.

The research of collapsibility test and FEA of collapse deformation in loess collapsible under overburden pressure

NASA Astrophysics Data System (ADS)

yu, Zhang; hui, Li; guibo, Bao; wuyu, Zhang; ningshan, Jiang; xiaoyun, Yang

2018-05-01

The collapsibility test in field may have huge error with computed results[1-4]. The writer gave a compare between single-line and double-line method and then compared with the field’s result. The writer’s purpose is to reduce the error of measured value to computed value and propose a way to decrease the error through consider the matric suction’s influence to unsaturated soil in using finite element analysis, field test was completed to verify the reasonability of this method and get some regulate of development of collapse deformation and supply some calculation basis of engineering design and forecast in emergency situation.

Gravitational collapse and the vacuum energy

NASA Astrophysics Data System (ADS)

Campos, M.

2014-03-01

To explain the accelerated expansion of the universe, models with interacting dark components (dark energy and dark matter) have been considered recently in the literature. Generally, the dark energy component is physically interpreted as the vacuum energy of the all fields that fill the universe. As the other side of the same coin, the influence of the vacuum energy on the gravitational collapse is of great interest. We study such collapse adopting different parameterizations for the evolution of the vacuum energy. We discuss the homogeneous collapsing star fluid, that interacts with a vacuum energy component, using the stiff matter case as example. We conclude this work with a discussion of the Cahill-McVittie mass for the collapsed object.

Inherently unstable networks collapse to a critical point

NASA Astrophysics Data System (ADS)

Sheinman, M.; Sharma, A.; Alvarado, J.; Koenderink, G. H.; MacKintosh, F. C.

2015-07-01

Nonequilibrium systems that are driven or drive themselves towards a critical point have been studied for almost three decades. Here we present a minimalist example of such a system, motivated by experiments on collapsing active elastic networks. Our model of an unstable elastic network exhibits a collapse towards a critical point from any macroscopically connected initial configuration. Taking into account steric interactions within the network, the model qualitatively and quantitatively reproduces results of the experiments on collapsing active gels.

Inter-plume aerodynamics for gasoline spray collapse

DOE PAGES

Sphicas, Panos; Pickett, Lyle M.; Skeen, Scott A.; ...

2017-11-10

The collapse or merging of individual plumes of direct-injection gasoline injectors is of fundamental importance to engine performance because of its impact on fuel–air mixing. But, the mechanisms of spray collapse are not fully understood and are difficult to predict. The purpose of this work is to study the aerodynamics in the inter-spray region, which can potentially lead to plume collapse. High-speed (100 kHz) particle image velocimetry is applied along a plane between plumes to observe the full temporal evolution of plume interaction and potential collapse, resolved for individual injection events. Supporting information along a line of sight is obtainedmore » using simultaneous diffused back illumination and Mie-scatter techniques. Experiments are performed under simulated engine conditions using a symmetric eight-hole injector in a high-temperature, high-pressure vessel at the “Spray G” operating conditions of the engine combustion network. Indicators of plume interaction and collapse include changes in counter-flow recirculation of ambient gas toward the injector along the axis of the injector or in the inter-plume region between plumes. Furthermore, the effect of ambient temperature and gas density on the inter-plume aerodynamics and the subsequent plume collapse are assessed. Increasing ambient temperature or density, with enhanced vaporization and momentum exchange, accelerates the plume interaction. Plume direction progressively shifts toward the injector axis with time, demonstrating that the plume interaction and collapse are inherently transient.« less

Inter-plume aerodynamics for gasoline spray collapse

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

Sphicas, Panos; Pickett, Lyle M.; Skeen, Scott A.

The collapse or merging of individual plumes of direct-injection gasoline injectors is of fundamental importance to engine performance because of its impact on fuel–air mixing. But, the mechanisms of spray collapse are not fully understood and are difficult to predict. The purpose of this work is to study the aerodynamics in the inter-spray region, which can potentially lead to plume collapse. High-speed (100 kHz) particle image velocimetry is applied along a plane between plumes to observe the full temporal evolution of plume interaction and potential collapse, resolved for individual injection events. Supporting information along a line of sight is obtainedmore » using simultaneous diffused back illumination and Mie-scatter techniques. Experiments are performed under simulated engine conditions using a symmetric eight-hole injector in a high-temperature, high-pressure vessel at the “Spray G” operating conditions of the engine combustion network. Indicators of plume interaction and collapse include changes in counter-flow recirculation of ambient gas toward the injector along the axis of the injector or in the inter-plume region between plumes. Furthermore, the effect of ambient temperature and gas density on the inter-plume aerodynamics and the subsequent plume collapse are assessed. Increasing ambient temperature or density, with enhanced vaporization and momentum exchange, accelerates the plume interaction. Plume direction progressively shifts toward the injector axis with time, demonstrating that the plume interaction and collapse are inherently transient.« less

Ontogenesis of the collapsed layer during haustorium development in the root hemi-parasite Santalum album Linn.

PubMed

Yang, X; Zhang, X; Teixeira da Silva, J A; Liang, K; Deng, R; Ma, G

2014-01-01

The structure and development of collapsed layers of the haustorium were studied in Santalum album Linn. Through light and transmission electron microscopy, it was shown that the collapsed layers originated from starch-containing cells when the haustorium developed an internal gland, thickened gradually and ultimately developed into the mantle, which, combined with the sucker, buckled the host root. We report on the presence of inter-collapsed layers for the first time. These layers develop after penetration into the host and are located between the intrusive tissues and the vascular meristematic region, gradually linking the collapsed layers and remains around the sucker. The proliferation of cells in the meristematic region and the 'host tropism' of cortical layers contribute to pressure within the haustorium and result in development of the collapsed layers. Besides, starch-containing cells that turn into collapsed layers are vulnerable to pressure as they lack a large vacuole, have uneven cell wall thickness and a loose cell arrangement. We proposed that the functions of collapsed layers are to efficiently assure that cell inclusion and energy concentrate at the inner meristematic region and are recycled to affect penetration, reinforce the physical connection between the sandalwood haustorium and host root, and supply space for haustorial development. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

Challenges in fitting a hearing aid to a severely collapsed ear canal and mixed hearing loss.

PubMed

Oeding, Kristi; Valente, Michael; Chole, Richard

2012-04-01

Collapsed ear canals typically occur when an outside force, such as a headset for audiometric testing, is present. However, when a collapsed ear canal occurs without external pressure, this creates a challenge not only for performing audiometric testing but also for coupling a hearing aid to the ear canal. This case report highlights the challenges associated with fitting a hearing aid on a patient with a severe anterior-posterior collapsed ear canal with a mixed hearing loss. A 67-yr-old female originally presented to Washington University in St. Louis School of Medicine in 1996 with a long-standing history of bilateral otosclerosis. She had chronic ear infections in the right ear and a severely collapsed ear canal in the left ear and was fit with a bone anchored hearing aid (BAHA®) on the right side in 2003. However, benefit from the BAHA started to decrease due to changes in hearing, and a different hearing solution was needed. It was proposed that a hearing aid be fit to her collapsed left ear canal; however, trying to couple a hearing aid to the collapsed ear canal required unique noncustom earmold solutions. This case study highlights some of the obstacles and potential solutions for coupling a hearing aid to a severely collapsed ear canal. American Academy of Audiology.

Scale-free gravitational collapse as the origin of ρ ˜ r-2 density profile - a possible role of turbulence in regulating gravitational collapse

NASA Astrophysics Data System (ADS)

Li, Guang-Xing

2018-03-01

Astrophysical systems, such as clumps that form star clusters share a density profile that is close to ρ ˜ r-2. We prove analytically this density profile is the result of the scale-free nature of the gravitational collapse. Therefore, it should emerge in many different situations as long as gravity is dominating the evolution for a period that is comparable or longer than the free-fall time, and this does not necessarily imply an isothermal model, as many have previously believed. To describe the collapse process, we construct a model called the turbulence-regulated gravitational collapse model, where turbulence is sustained by accretion and dissipates in roughly a crossing time. We demonstrate that a ρ ˜ r-2 profile emerges due to the scale-free nature the system. In this particular case, the rate of gravitational collapse is regulated by the rate at which turbulence dissipates the kinetic energy such that the infall speed can be 20-50% of the free-fall speed(which also depends on the interpretation of the crossing time based on simulations of driven turbulence). These predictions are consistent with existing observations, which suggests that these clumps are in the stage of turbulence-regulated gravitational collapse. Our analysis provides a unified description of gravitational collapse in different environments.

Quality of Care and the Burden of Two Cultures: When the World of the Nurse's Aide Enters the World of the Nursing Home.

ERIC Educational Resources Information Center

Tellis-Nayak, V.; Tellis-Nayak, Mary

1989-01-01

Used ethnographic data to examine personal and work worlds of nurse's aides. Concludes that, because nursing home's institutional culture often adds to adversity of their personal life, nurse's aides move between the two milieus in self-perpetuating negative cycle, carrying to bedside of elderly residents the affective and psychological burden…

Visualizing the Histotripsy Process: Bubble Cloud-Cancer Cell Interactions in a Tissue-Mimicking Environment.

PubMed

Vlaisavljevich, Eli; Maxwell, Adam; Mancia, Lauren; Johnsen, Eric; Cain, Charles; Xu, Zhen

2016-10-01

Histotripsy is a non-invasive ultrasonic ablation method that uses cavitation to mechanically fractionate tissue into acellular debris. With a sufficient number of pulses, histotripsy can completely fractionate tissue into a liquid-appearing homogenate with no cellular structures. The location, shape and size of lesion formation closely match those of the cavitation cloud. Previous work has led to the hypothesis that the rapid expansion and collapse of histotripsy bubbles fractionate tissue by inducing large stress and strain on the tissue structures immediately adjacent to the bubbles. In the work described here, the histotripsy bulk tissue fractionation process is visualized at the cellular level for the first time using a custom-built 2-MHz transducer incorporated into a microscope stage. A layer of breast cancer cells were cultured within an optically transparent fibrin-based gel phantom to mimic cells inside a 3-D extracellular matrix. To test the hypothesis, the cellular response to single and multiple histotripsy pulses was investigated using high-speed optical imaging. Bubbles were always generated in the extracellular space, and significant cell displacement/deformation was observed for cells directly adjacent to the bubble during both bubble expansion and collapse. The largest displacements were observed during collapse for cells immediately adjacent to the bubble, with cells moving more than 150-300 μm in less than 100 μs. Cells often underwent multiple large deformations (>150% strain) over multiple pulses, resulting in the bisection of cells multiple times before complete removal. To provide theoretical support to the experimental observations, a numerical simulation was conducted using a single-bubble model, which indicated that histotripsy exerts the largest strains and cell displacements in the regions immediately adjacent to the bubble. The experimental and simulation results support our hypothesis, which helps to explain the formation of the sharp lesions formed in histotripsy therapy localized to the regions directly exposed to the bubbles. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Acoustic Behavior of Halobacterium salinarum Gas Vesicles in the High-Frequency Range: Experiments and Modeling.

PubMed

Cherin, Emmanuel; Melis, Johan M; Bourdeau, Raymond W; Yin, Melissa; Kochmann, Dennis M; Foster, F Stuart; Shapiro, Mikhail G

2017-05-01

Gas vesicles (GVs) are a new and unique class of biologically derived ultrasound contrast agents with sub-micron size whose acoustic properties have not been fully elucidated. In this study, we investigated the acoustic collapse pressure and behavior of Halobacterium salinarum gas vesicles at transmit center frequencies ranging from 12.5 to 27.5 MHz. The acoustic collapse pressure was found to be above 550 kPa at all frequencies, nine-fold higher than the critical pressure observed under hydrostatic conditions. We illustrate that gas vesicles behave non-linearly when exposed to ultrasound at incident pressure ranging from 160 kPa to the collapse pressure and generate second harmonic amplitudes of -2 to -6 dB below the fundamental in media with viscosities ranging from 0.89 to 8 mPa·s. Simulations performed using a Rayleigh-Plesset-type model accounting for buckling and a dynamic finite-element analysis suggest that buckling is the mechanism behind the generation of harmonics. We found good agreement between the level of second harmonic relative to the fundamental measured at 20 MHz and the Rayleigh-Plesset model predictions. Finite-element simulations extended these findings to a non-spherical geometry, confirmed that the acoustic buckling pressure corresponds to the critical pressure under hydrostatic conditions and support the hypothesis of limited gas flow across the GV shell during the compression phase in the frequency range investigated. From simulations, estimates of GV bandwidth-limited scattering indicate that a single GV has a scattering cross section comparable to that of a red blood cell. These findings will inform the development of GV-based contrast agents and pulse sequences to optimize their detection with ultrasound. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Gravitational Failures of Lava Domes at Intersections With Tectonic Faults: Examples from Tatun Volcanic Group, Northern Taiwan

NASA Astrophysics Data System (ADS)

Belousova, M.; Belousov, A.; Chen, C.

2009-12-01

The dominantly andesitic Tatun Volcanic Group of Northern Taiwan was formed during the Pleistocene - Early Holocene. The volcanoes are represented by lava domes of moderate sizes: heights up to 350 m (absolute altitudes 800 - 1120 m a.s.l.), base diameters up to 1.5 km, and volumes up to 0.3 km3. Many of the domes have broad, shallow horseshoe-shaped scars (0.5-1.0 km across) formed by gravitational collapses. Field examination revealed deposits of collapses of volcanoes Datun, Cising, Siaoguanyin, Cigu, and Dajianhou. The largest of the collapses (V ~ 0.1 km3) occurred at Mt. Datun. The collapse formed a typical debris avalanche deposit composed mainly of block facies. The avalanche traveled a distance L ~ 5 km, dropped a height H ~ 1 km, and was moderately mobile H/L ~ 0.2. The age of the collapse is > 24,000 yrs because the related debris avalanche deposit is covered by a younger debris avalanche deposit of Siaoguanyin volcano containing charcoal having calibrated 14C age 22,600-23,780 BP. The Siaoguanyin debris avalanche deposit (V~ 0.02 km3; L ~ 6 km; H ~ 1 km; H/L ~ 0.16) is composed of massive, very coarse-grained, fines-poor, gravelly material represented predominantly by very dense, dark-grey andesite. The avalanche was hot during deposition; material of a lava dome which had no time to cool down completely after extrusion was involved into the collapse. The avalanche speed was 40 m/s at a distance 5 km from the source, basing on 80 m of the avalanche run-up. The latest (calibrated age 6000-6080 BP) large-scale collapse (V~0.05 km3, H/L ~ 0.25) occurred at Mt. Cising in the form of numerous retrogressive landslide blocks, which did not transform into a long runout debris avalanche. The leading snout of the landslide traveled 2.0 km, while rear slide blocks traveled only several hundred meters and stopped near the landslide source. Its maximum dropped height is only ~0.5 km. A former lava coulee, which was involved in the collapse, underwent weak disintegration: material of the collapse is represented by big boulders with few fine grained matrix. Collapses of Cigu and Dajianhou volcanoes had the smallest volumes, ~ 0.01 km3, and their character is transitional to large rockfalls. The studied collapses occurred after the volcanoes had stopped erupting, and thus were not triggered by volcanic activity. Hydrothermally altered rocks do not compose significant parts of the studied debris avalanches, although hydrothermal fields are common in the scars of the collapses. Probably weakening of mechanical properties of the volcanic edifices due to hydrothermal alteration did not play a key role in the studied collapses, but elevated fluid pressure and hydrothermal alteration in the foundations of the volcanoes might have had some role. Scars of the collapses are located on intersections of the edifices with active tectonic faults of NNE-SSW and/or W-E strike, which are expressed in relief and clearly visible on space images. Thus, the collapsed parts of the volcanic edifices were detached by tectonic motions, and the collapses were possibly triggered by seismic activity.

Collapsing lattice animals and lattice trees in two dimensions

NASA Astrophysics Data System (ADS)

Hsu, Hsiao-Ping; Grassberger, Peter

2005-06-01

We present high statistics simulations of weighted lattice bond animals and lattice trees on the square lattice, with fugacities for each non-bonded contact and for each bond between two neighbouring monomers. The simulations are performed using a newly developed sequential sampling method with resampling, very similar to the pruned-enriched Rosenbluth method (PERM) used for linear chain polymers. We determine with high precision the line of second-order transitions from an extended to a collapsed phase in the resulting two-dimensional phase diagram. This line includes critical bond percolation as a multicritical point, and we verify that this point divides the line into different universality classes. One of them corresponds to the collapse driven by contacts and includes the collapse of (weakly embeddable) trees. There is some evidence that the other is subdivided again into two parts with different universality classes. One of these (at the far side from collapsing trees) is bond driven and is represented by the Derrida-Herrmann model of animals having bonds only (no contacts). Between the critical percolation point and this bond-driven collapse seems to be an intermediate regime, whose other end point is a multicritical point P* where a transition line between two collapsed phases (one bond driven and the other contact driven) sparks off. This point P* seems to be attractive (in the renormalization group sense) from the side of the intermediate regime, so there are four universality classes on the transition line (collapsing trees, critical percolation, intermediate regime, and Derrida-Herrmann). We obtain very precise estimates for all critical exponents for collapsing trees. It is already harder to estimate the critical exponents for the intermediate regime. Finally, it is very difficult to obtain with our method good estimates of the critical parameters of the Derrida-Herrmann universality class. As regards the bond-driven to contact-driven transition in the collapsed phase, we have some evidence for its existence and rough location, but no precise estimates of critical exponents.

Costa Rica's Chain of laterally collapsed volcanoes.

NASA Astrophysics Data System (ADS)

Duarte, E.; Fernandez, E.

2007-05-01

From the NW extreme to the SW end of Costa Rica's volcanic backbone, a number of laterally collapsed volcanoes can be observed. Due to several factors, attention has been given to active volcanoes disregarding the importance of collapsed features in terms of assessing volcanic hazards for future generations around inhabited volcanoes. In several cases the typical horseshoe shape amphitheater-like depression can be easily observed. In other cases due to erosion, vegetation, topography, seismic activity or drastic weather such characteristics are not easily recognized. In the order mentioned above appear: Orosi-Cacao, Miravalles, Platanar, Congo, Von Frantzius, Cacho Negro and Turrialba volcanoes. Due to limited studies on these structures it is unknown if sector collapse occurred in one or several phases. Furthermore, in the few studied cases no evidence has been found to relate collapses to actual eruptive episodes. Detailed studies on the deposits and materials composing dome-like shapes will shed light on unsolved questions about petrological and chemical composition. Volume, form and distance traveled by deposits are part of the questions surrounding most of these collapsed volcanoes. Although most of these mentioned structures are extinct, at least Irazú volcano (active volcano) has faced partial lateral collapses recently. It did presented strombolian activity in the early 60s. Collapse scars show on the NW flank show important mass removal in historic and prehistoric times. Moreover, in 1994 a minor hydrothermal explosion provoked the weakening of a deeply altered wall that holds a crater lake (150m diameter, 2.6x106 ). A poster will depict images of the collapsed volcanoes named above with mayor descriptive characteristics. It will also focus on the importance of deeper studies to assess the collapse potential of Irazú volcano with related consequences. Finally, this initiative will invite researchers interested in such topic to join future studies in these Costarrican volcanoes.