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1

ExtraTerrestrial Intelligence  

E-print Network

SETI Search for ExtraTerrestrial Intelligence I know perfectly well that at this moment the whole, The Madwoman of Chaillot #12;Options Passive SETI: Listen Active SETI: Transmit #12;Search Strategies Suppose you find a civilization. You want to communicate. How? #12;Search Strategies There are two issues: A

Walter, Frederick M.

2

SETI: Search for ExtraTerrestrial Intelligence  

E-print Network

SETI: Search for ExtraTerrestrial Intelligence I know perfectly well that at this moment the whole, The Madwoman of Chaillot #12;Search Strategies Suppose you find a civilization. You want to communicate. How? #12;Options Passive SETI: Listen Active SETI: Transmit #12;Search Strategies There are two issues: A

Walter, Frederick M.

3

SETI [Search for ExtraTerrestrial Intelligence  

Microsoft Academic Search

Some critics of the Search for Extra-Terrestrial Intelligence (SETI) like to bolster their arguments with what they call the Fermi Paradox. Legend has it that one day at Los Alamos, shortly after the Alamogordo test (when the first atomic bomb was exploded in the desert about 50 miles northwest of this town on July 16, 1945), Enrico Fermi abruptly broke

B. M. Oliver

1994-01-01

4

The search for extra-terrestrial intelligence.  

PubMed

Modern history of the search for extra-terrestrial intelligence is reviewed. The history of radio searches is discussed, as well as the major advances that have occurred in radio searches and prospects for new instruments and search strategies. Recent recognition that searches for optical and infrared signals make sense, and the reasons for this are described, as well as the equipment and special detection methods used in optical searches. The long-range future of the search for extra-terrestrial intelligence (SETI) is discussed in the context of the history of rapid change, on the cosmic and even the human time scale, of the paradigms guiding SETI searches. This suggests that SETI searches be conducted with a very open mind. PMID:21220287

Drake, Frank

2011-02-13

5

Terrestrial Planet Formation in Extra-Solar Planetary Systems  

E-print Network

Terrestrial planets form in a series of dynamical steps from the solid component of circumstellar disks. First, km-sized planetesimals form likely via a combination of sticky collisions, turbulent concentration of solids, and gravitational collapse from micron-sized dust grains in the thin disk midplane. Second, planetesimals coalesce to form Moon- to Mars-sized protoplanets, also called "planetary embryos". Finally, full-sized terrestrial planets accrete from protoplanets and planetesimals. This final stage of accretion lasts about 10-100 Myr and is strongly affected by gravitational perturbations from any gas giant planets, which are constrained to form more quickly, during the 1-10 Myr lifetime of the gaseous component of the disk. It is during this final stage that the bulk compositions and volatile (e.g., water) contents of terrestrial planets are set, depending on their feeding zones and the amount of radial mixing that occurs. The main factors that influence terrestrial planet formation are the mass and surface density profile of the disk, and the perturbations from giant planets and binary companions if they exist. Simple accretion models predicts that low-mass stars should form small, dry planets in their habitable zones. The migration of a giant planet through a disk of rocky bodies does not completely impede terrestrial planet growth. Rather, "hot Jupiter" systems are likely to also contain exterior, very water-rich Earth-like planets, and also "hot Earths", very close-in rocky planets. Roughly one third of the known systems of extra-solar (giant) planets could allow a terrestrial planet to form in the habitable zone.

Sean N. Raymond

2008-01-16

6

Messaging to Extra-Terrestrial Intelligence  

E-print Network

Throughout the entire history of terrestrial civilization, only four projects involving transmitting of interstellar radio messages (IRMs) have yet been fully developed and realized. Nevertheless, we should understand a simple thing -- if all civilizations in the Universe are only recipients, and not message-sending civilizations, than no SETI searches make any sense. We present the theory and methodology of composing and transmitting of future IRMs.

Alexander Zaitsev

2006-10-05

7

The Terrestrial Planets Large Bodies  

E-print Network

: Greenhouse Effect: Solar heating & atmospheric cooling balance Helps determine if H2O is liquid, ice atmosphere. May have had early oceans that evaporated resulting in a Runaway Greenhouse Effect. Gravity elements. #12;The evolution of Terrestrial Planet atmospheres is driven by three primary effects

Gaudi, B. Scott

8

A Review of Extra-Terrestrial Mining Robot Concepts  

NASA Technical Reports Server (NTRS)

Outer space contains a vast amount of resources that offer virtually unlimited wealth to the humans that can access and use them for commercial purposes. One of the key technologies for harvesting these resources is robotic mining of regolith, minerals, ices and metals. The harsh environment and vast distances create challenges that are handled best by robotic machines working in collaboration with human explorers. Humans will benefit from the resources that will be mined by robots. They will visit outposts and mining camps as required for exploration, commerce and scientific research, but a continuous presence is most likely to be provided by robotic mining machines that are remotely controlled by humans. There have been a variety of extra-terrestrial robotic mining concepts proposed over the last 100 years and this paper will attempt to summarize and review concepts in the public domain (government, industry and academia) to serve as an informational resource for future mining robot developers and operators. The challenges associated with these concepts will be discussed and feasibility will be assessed. Future needs associated with commercial efforts will also be investigated.

Mueller, Robert P.; Van Susante, Paul J.

2011-01-01

9

A Review of Extra-Terrestrial Mining Concepts  

NASA Technical Reports Server (NTRS)

Outer space contains a vast amount of resources that offer virtually unlimited wealth to the humans that can access and use them for commercial purposes. One of the key technologies for harvesting these resources is robotic mining of regolith, minerals, ices and metals. The harsh environment and vast distances create challenges that are handled best by robotic machines working in collaboration with human explorers. Humans will benefit from the resources that will be mined by robots. They will visit outposts and mining camps as required for exploration, commerce and scientific research, but a continuous presence is most likely to be provided by robotic mining machines that are remotely controlled by humans. There have been a variety of extra-terrestrial robotic mining concepts proposed over the last 40 years and this paper will attempt to summarize and review concepts in the public domain (government, industry and academia) to serve as an informational resource for future mining robot developers and operators. The challenges associated with these concepts will be discussed and feasibility will be assessed. Future needs associated with commercial efforts will also be investigated.

Mueller, R. P.; van Susante, P. J.

2012-01-01

10

Applying Biomimetic Algorithms for Extra-Terrestrial Habitat Generation  

NASA Technical Reports Server (NTRS)

The objective is to simulate and optimize distributed cooperation among a network of robots tasked with cooperative excavation on an extra-terrestrial surface. Additionally to examine the concept of directed Emergence among a group of limited artificially intelligent agents. Emergence is the concept of achieving complex results from very simple rules or interactions. For example, in a termite mound each individual termite does not carry a blueprint of how to make their home in a global sense, but their interactions based strictly on local desires create a complex superstructure. Leveraging this Emergence concept applied to a simulation of cooperative agents (robots) will allow an examination of the success of non-directed group strategy achieving specific results. Specifically the simulation will be a testbed to evaluate population based robotic exploration and cooperative strategies while leveraging the evolutionary teamwork approach in the face of uncertainty about the environment and partial loss of sensors. Checking against a cost function and 'social' constraints will optimize cooperation when excavating a simulated tunnel. Agents will act locally with non-local results. The rules by which the simulated robots interact will be optimized to the simplest possible for the desired result, leveraging Emergence. Sensor malfunction and line of sight issues will be incorporated into the simulation. This approach falls under Swarm Robotics, a subset of robot control concerned with finding ways to control large groups of robots. Swarm Robotics often contains biologically inspired approaches, research comes from social insect observation but also data from among groups of herding, schooling, and flocking animals. Biomimetic algorithms applied to manned space exploration is the method under consideration for further study.

Birge, Brian

2012-01-01

11

(Astro)Physics 343 Lecture # 14: the Search for ExtraTerrestrial Intelligence  

E-print Network

(Astro)Physics 343 Lecture # 14: the Search for ExtraTerrestrial Intelligence #12 about astrobiology guide our choice of search strategy. #12; What astrobiology encompasses astronomy and detection of extraterrestrial life. Location inspired by Drake's first SETI experiment. Participants

Baker, Andrew J.

12

Reducing Extra-Terrestrial Excavation Forces with Percussion  

NASA Technical Reports Server (NTRS)

High launch costs and mission requirements drive the need for low mass excavators with mobility platforms, which in turn have little traction and excavation reaction capacity in low gravity environments. This presents the need for precursor and long term future missions with low mass robotic mining technology to perform In-Situ Resource Utilization (ISRU) tasks. This paper discusses a series of experiments that investigate the effectiveness of a percussive digging device to reduce excavation loads and thereby the mass of the excavator itself. The goal of percussive excavation is to fluidize dry regolith in front of the leading edge of the tool by mechanically separating the microscopic interlocking grains resulting in a reduced force needed to shear the soil. There are several variables involved with this technique; this experiment varied: Impact energy, frequency, and excavation speed and held constant: impact direction, depth of cut, angle of tool, and soil bulk density. The test apparatus consisted of an aluminum truss bridge with a central pivoting arm. Attached to the arm was a winch with a load cell in line that recorded the tension in the cable and therefore the excavation load. The arm could be adjusted for excavation depth which was recorded along with the arm angle relative to the bridge. A percussive mechanism and 30" wide pivoting bucket were attached at the end of the arm simulating a basic backhoe with a percussion direction tangent to the direction of . movement. Internally the mechanism used a set of die springs and barrel cam to produce the percussive blow. By changing the springs and the speed of the motor the impact energy and frequency of percussion could be varied independently. Impact energies from 11.2J to 30.5J and frequencies from 0 BPM to 700 BPM were investigated. A reduction in excavation force of as much as 51% was achieved in this experimental investigation. Smaller percussive digging implements, tested by others, have achieved a reduction of as much as 72%. This paper will examine the effects of impact energy, frequency, scaling and their effect on excavation forces in a dry granular material such as lunar regolith. The past several years have shown an increasing interest in mining space resources both for exploration and commercial enterprises. This work studied the benefits and risks of percussive excavation and preliminry results indicate that this technique may become an enabling technology for extra-terrestrial excavation of regolith and ice.

Schuler, Jason; Mueller, Robert; Smith, Drew; Nick, Andrew; Lippitt, Thomas

2012-01-01

13

Search for Extra-Terrestrial Intelligence The following is from The Sixth Book of Mathematical Games from Sci-  

E-print Network

Search for Extra-Terrestrial Intelligence The following is from The Sixth Book of Mathematical Games from Sci- entific American by Martin Gardner. Suppose you want to send a message to extra-terrestrials, American Mathematical Monthly 105 (1998) 640­650.) The following proposed message to extraterrestrials

Lee, Carl

14

Physics 343 Lecture # 14: the Search for ExtraTerrestrial Intelligence  

E-print Network

Physics 343 Lecture # 14: the Search for ExtraTerrestrial Intelligence and galactic collisions about astrobiology guide our choice of search strategy. #12; Quantifying our ignorance... UC Santa scientists met in Green Bank, WV to discuss the prospect for existence and detection of extraterrestrial

Baker, Andrew J.

15

Topographic-driven instabilities in terrestrial bodies  

NASA Astrophysics Data System (ADS)

Models of internal planetary fluid layers (core flows, subsurface oceans) commonly assume that these fluid envelopes have a spherical shape. This approximation however entails a serious restriction from the fluid dynamics point of view. Indeed, in the presence of mechanical forcings (precession, libration, nutation or tides) due to gravitational interaction with orbiting partners, boundary topography (e.g. of the core-mantle boundary) may excite flow instabilities and space-filling turbulence. These phenomena may affect heat transport and dissipation at the main order. Here, we focus on instabilities driven by longitudinal libration. Using a suite of theoretical tools and numerical simulations, we are able to discern a parameter range for which instability may be excited. We thereby consider deformations of different azimuthal order. This study gives the first numerical evidence of the tripolar instability. Furthermore, we explore the non-linear regime and investigate the amplitude as well as the dissipation of the saturated instability. Indeed, these two quantities control the torques on the solid layers and the thermal transport. Furthermore, based on this results, we address the issue of magnetic field generation associated with these flows (by induction or by dynamo process). This instability mechanism applies to both synchronized as non-synchronized bodies. As such, our results show that a tripolar instability might be present in various terrestrial bodies (Early Moon, Gallilean moons, asteroids, etc.), where it could participate in dynamo action. Simulation of a libration-driven tripolar instability in a deformed spherical fluid layer: snapshot of the velocity magnitude, where a complex 3D flow pattern is established.

Vantieghem, S.; Cebron, D.; Herreman, W.; Lacaze, L.

2013-12-01

16

Tidal Heating of Terrestrial Extra-Solar Planets and Implications for their Habitability  

E-print Network

The tidal heating of hypothetical rocky (or terrestrial) extra-solar planets spans a wide range of values depending on stellar masses and initial orbits. Tidal heating may be sufficiently large (in many cases, in excess of radiogenic heating) and long-lived to drive plate tectonics, similar to the Earth's, which may enhance the planet's habitability. In other cases, excessive tidal heating may result in Io-like planets with violent volcanism, probably rendering them unsuitable for life. On water-rich planets, tidal heating may generate sub-surface oceans analogous to Europa's with similar prospects for habitability. Tidal heating may enhance the outgassing of volatiles, contributing to the formation and replenishment of a planet's atmosphere. To address these issues, we model the tidal heating and evolution of hypothetical extra-solar terrestrial planets. The results presented here constrain the orbital and physical properties required for planets to be habitable.

Brian Jackson; Rory Barnes; Richard Greenberg

2008-08-20

17

Tidal Heating of Terrestrial Extra-Solar Planets and Implications for their Habitability  

E-print Network

The tidal heating of hypothetical rocky (or terrestrial) extra-solar planets spans a wide range of values depending on stellar masses and initial orbits. Tidal heating may be sufficiently large (in many cases, in excess of radiogenic heating) and long-lived to drive plate tectonics, similar to the Earth's, which may enhance the planet's habitability. In other cases, excessive tidal heating may result in Io-like planets with violent volcanism, probably rendering them unsuitable for life. On water-rich planets, tidal heating may generate sub-surface oceans analogous to Europa's with similar prospects for habitability. Tidal heating may enhance the outgassing of volatiles, contributing to the formation and replenishment of a planet's atmosphere. To address these issues, we model the tidal heating and evolution of hypothetical extra-solar terrestrial planets. The results presented here constrain the orbital and physical properties required for planets to be habitable.

Jackson, Brian; Greenberg, Richard

2008-01-01

18

Power optimization of an extra-terrestrial, solar-radiant stirling heat engine  

Microsoft Academic Search

The power output and thermal efficiency of a finite-time, optimized, extra-terrestrial, solar-radiant Stirling heat engine have been studied. The thermodynamic model adopted is a regenerative gas Stirling cycle coupled to a heat source and heat sink by radiant heat transfer. Both the heat source and sink are assumed to have infinite heat-capacity rates. Expressions are obtained for optimum power and

David A. Blank; Chih Wu

1995-01-01

19

Fear, pandemonium, equanimity and delight: human responses to extra-terrestrial life.  

PubMed

How will people respond to the discovery of extra-terrestrial life? Potentially useful resources for addressing this question include historical prototypes, disaster studies and survey research. Reactions will depend on the interplay of the characteristics of the newly found life, the unfolding of the discovery, the context and content of the message and human information processing as shaped by biology, culture and psychology. Pre-existing images of extra-terrestrials as god-like, demonic, or artificial will influence first impressions that may prove highly resistant to change. Most probably people will develop comprehensive images based on minimal information and assess extra-terrestrials in the same ways that they assess one another. Although it is easy to develop frightening scenarios, finding microbial life in our Solar System or intercepting a microwave transmission from many light years away are less likely to be met with adverse reactions such as fear and pandemonium than with positive reactions such as equanimity and delight. PMID:21220289

Harrison, Albert A

2011-02-13

20

Predicting what extra-terrestrials will be like: and preparing for the worst.  

PubMed

It is difficult to imagine evolution in alien biospheres operating in any manner other than Darwinian. Yet, it is also widely assumed that alien life-forms will be just that: strange, un-nerving and probably repulsive. There are two reasons for this view. First, it is assumed that the range of habitable environments available to extra-terrestrial life is far wider than on Earth. I suggest, however, that terrestrial life is close to the physical and chemical limits of life anywhere. Second, it is a neo-Darwinian orthodoxy that evolution lacks predictability; imagining what extra-terrestrial life would look like in any detail is a futile exercise. To the contrary, I suggest that the outcomes of evolution are remarkably predictable. This, however, leads us to consider two opposites, both of which should make our blood run cold. The first, and actually extremely unlikely, is that alien biospheres will be strikingly similar to our terrestrial equivalent and that in such biospheres intelligence will inevitably emerge. The reasons for this revolve around the ubiquity of evolutionary convergence, the determinate structure of the Tree of Life and molecular inherency. But if something like a human is an inevitability, why do I also claim that the first possibility is 'extremely unlikely'? Simply because the other possibility is actually the correct answer. Paradoxically, we and our biosphere are completely alone. So which is worse? Meeting ourselves or meeting nobody? PMID:21220280

Morris, Simon Conway

2011-02-13

21

Montana Evidence for Extra-Terrestrial Impact Event That Caused Ice-Age Mammal Die- Off  

NASA Astrophysics Data System (ADS)

Evidence has been found in Montana for an extra-terrestrial impact event previously documented in the States of AZ, NM, NC, and SC and in Alberta and Manitoba. A mammoth fossil site dated at 11.5 ka (C14) before present (BP) was described in 1969 as the last mammoth occurrence in Montana. The mammoth remains were found in an organic-rich layer--a black mat. The black mat contains abundant charcoal (evidence for forest fire), black carbon glass foam, plant material deposited in a pond, and unrusted iron micro-meteorites. SEM photos of iron micro-meteorites reveal fusion crusts, flow lines, and micro-impact craters--direct evidence for an extra- terrestrial origin. One 140 ?m long micro-meteorite is 96 wt.% Fe and 4% Mn. Another is 71% Fe and 29% Ti. Mammoth tusks contain rusty pits, consistent with iron micro-meteorites that were embedded and then rusted out. A sample of carbon glass in the black mat contains 62% C, 22% O, 6% Fe, 4% Ca, 4% Si, and 2% Al. At the Indian Creek Archeological Site near Townsend, MT below the cultural layers and below a 11.2 ka (C14) volcanic ash layer there are individual glass bubbles about 1 mm in diameter with micro-impact craters. The size distribution of these micro-craters resembles the size distribution of lunar craters, but at a vastly different scale. The glass contains 53% C, 33% O, 6% Ca, 4% Si, 2% Al, 1% Mg, and 0.6% K. The carbon glass and micro-meteorites suggest a comet rather a meteorite origin for the extra-terrestrial material.

Baker, D. W.; Miranda, P. J.; Gibbs, K. E.

2008-05-01

22

Chemical methods for searching for evidence of extra-terrestrial life.  

PubMed

This paper describes the chemical concepts used for the purpose of detecting life in extra-terrestrial situations. These methods, developed initially within the oil industry, have been used to determine when life began on Earth and for investigating the Moon and Mars via space missions. In the case of Mars, the Viking missions led to the realization that we had meteorites from Mars on Earth. The study of Martian meteorites in the laboratory provides tantalizing clues for life on Mars in both the ancient and recent past. Meteorite analyses led to the launch of the Beagle 2 spacecraft, which was designed to prove that life-detection results obtained on Earth were authentic and not confused by terrestrial contamination. Some suggestions are made for future work. PMID:21220284

Pillinger, Colin

2011-02-13

23

ORIGINS OF NON-MASS-DEPENDENT FRACTIONATION OF EXTRA-TERRESTRIAL OXYGEN  

SciTech Connect

The distribution of oxygen isotopes in meteorites and within the earliest solids that formed in the solar system hints that the precursors of these materials must have undergone a mass-independent process. The mass-independent process is specifically one that fractionates {sup 16}O from {sup 17}O and {sup 18}O. This chemical signature is indicative of non-equilibrium processing, which bear resemblance to some unusual terrestrial phenomenon such as fractionation of ozone in the upper Earth atmosphere. That the mass-independent fractionation of oxygen isotopes is preserved within petrological records presents planetary scientists interesting clues to the events that may have occurred during the formation of the solar system. Currently, there are several hypotheses on the origins of the oxygen isotope distribution within primitive planetary materials, which include both thermal and photochemical models. We present a new model based on a physico-chemical hypothesis for the origin of non-mass-dependent O-isotope distribution in oxygen-bearing extra-terrestrial materials, which originated from the disproportionation of CO in dark molecular clouds to create CO{sub 2} reservoirs. The disproportionation created a reservoir of heavy oxygen isotopes and could have occurred throughout the evolution of the disk. The CO{sub 2} was a carrier of the isotope anomaly in the solar nebula and we propose that non-steady-state mixing of these reservoirs with the early rock-forming materials during their formation corresponds with the birth and evolution of the solar system.

Barcena, Homar; Connolly, Harold C. [Department of Physical Sciences, Kingsborough Community College of the City University of New York, 2001 Oriental Boulevard, Brooklyn, NY 11235 (United States)

2012-08-01

24

Simulation of a Space-Based Microlensing Survey for Terrestrial Extra-Solar Planets  

E-print Network

We show that a space-based gravitational microlensing survey for terrestrial extra-solar planets is feasible in the near future, and could provide a nearly complete picture of the properties of planetary systems in our Galaxy. We present simulations of such a survey using a 1-2m aperture space telescope with a ~2 square degree field-of-view which is used to continuously monitor ~10^8 Galactic bulge main sequence stars. The microlensing techniques allows the discovery of low mass planets with high signal-to-noise, and the space mission that we have studied are sensitive to planets with masses as low as that of Mars. By targeting main sequence source stars, which can only be resolved from space, the space-based microlensing survey is able to detect enough light from the lens stars to determine the spectral type of one third of the lens stars with detected planets, including virtually all of the F, G, and K stars which comprise one quarter of the event sample. This enables the determination of the planetary masses and separations in physical units, as well as the abundance of planets as a function of stellar type and distance from the Galactic center. We show that a space-based microlensing planet search program has its highest sensitivity to planets at orbital separations of 0.7-10 AU, but it will also have significant sensitivity at larger separations and will be able to detect free-floating planets in significant numbers. This complements the planned terrestrial planet transit missions which are sensitive to terrestrial planets at separations of =planets via transits, and it is, therefore, the only proposed planet detection method that is sensitive to planets at all orbital radii.

David P. Bennett; Sun Hong Rhie

2002-02-01

25

The game of active search for extra-terrestrial intelligence: breaking the `Great Silence'  

NASA Astrophysics Data System (ADS)

The search for extra-terrestrial intelligence (SETI) has been performed principally as a one-way survey, listening of radio frequencies across the Milky Way and other galaxies. However, scientists have engaged in an active messaging only rarely. This suggests the simple rationale that if other civilizations exist and take a similar approach to ours, namely listening but not broadcasting, the result is a silent universe. A simple game theoretical model, the prisoner's dilemma, explains this situation: each player (civilization) can passively search (defect), or actively search and broadcast (cooperate). In order to maximize the payoff (or, equivalently, minimize the risks) the best strategy is not to broadcast. In fact, the active search has been opposed on the basis that it might be dangerous to expose ourselves. However, most of these ideas have not been based on objective arguments, and ignore accounting of the possible gains and losses. Thus, the question stands: should we perform an active search? I develop a game-theoretical framework where civilizations can be of different types, and explicitly apply it to a situation where societies are either interested in establishing a two-way communication or belligerent and in urge to exploit ours. The framework gives a quantitative solution (a mixed-strategy), which is how frequent we should perform the active SETI. This frequency is roughly proportional to the inverse of the risk, and can be extremely small. However, given the immense amount of stars being scanned, it supports active SETI. The model is compared with simulations, and the possible actions are evaluated through the San Marino scale, measuring the risks of messaging.

de Vladar, Harold P.

2013-01-01

26

Extra!  

NSDL National Science Digital Library

The national media watch group Fairness & Accuracy in Reporting (FAIR) was started in 1986 in order to "invigorate the First Amendment by advocating for greater diversity in the press and by scrutinizing media practices that marginalize public interest, minority and dissenting viewpoints." As part of this work, FAIR publishes Extra!, which is a monthly magazine of well-documented media criticism and commentary. The first issue was published in June 1987, and this website gives interested parties access to many of the articles that have been published over the past twenty-plus years. The magazine receives no money from advertisers or underwriters, and as such, they are able to offer less biased, objective commentary on many of key media issues. Recent articles from Extra! have included a critical assessment of PBS's flagship news show "NewsHour" and an assessment of the Sonny Bono Copyright Term Extension Act, which deals with copyright extensions on books, movies, and so on. Visitors can also browse their "Back Issues" here and sign up for their email list.

27

Examining predator-prey body size, trophic level and body mass across marine and terrestrial mammals.  

PubMed

Predator-prey relationships and trophic levels are indicators of community structure, and are important for monitoring ecosystem changes. Mammals colonized the marine environment on seven separate occasions, which resulted in differences in species' physiology, morphology and behaviour. It is likely that these changes have had a major effect upon predator-prey relationships and trophic position; however, the effect of environment is yet to be clarified. We compiled a dataset, based on the literature, to explore the relationship between body mass, trophic level and predator-prey ratio across terrestrial (n = 51) and marine (n = 56) mammals. We did not find the expected positive relationship between trophic level and body mass, but we did find that marine carnivores sit 1.3 trophic levels higher than terrestrial carnivores. Also, marine mammals are largely carnivorous and have significantly larger predator-prey ratios compared with their terrestrial counterparts. We propose that primary productivity, and its availability, is important for mammalian trophic structure and body size. Also, energy flow and community structure in the marine environment are influenced by differences in energy efficiency and increased food web stability. Enhancing our knowledge of feeding ecology in mammals has the potential to provide insights into the structure and functioning of marine and terrestrial communities. PMID:25377460

Tucker, Marlee A; Rogers, Tracey L

2014-12-22

28

Extra source implantation for suppression floating-body effect in partially depleted SOI MOSFETs  

NASA Astrophysics Data System (ADS)

Silicon-on-insulate (SOI) MOSFETs offer benefits over bulk competitors for fully isolation and smaller junction capacitance. The performance of partially depleted (PD) SOI MOSFETs, though, is not good enough. Since the body is floating, the extra holes (for nMOSFETs) in this region accumulate, causing body potential arise, which of course degrades the performance of the device. How to suppress the floating-body effect becomes critical. There are mainly two ways for the goal. One is to employ body-contact structures, and the other SiGe source/drain structures. However, the former consumes extra area, not welcomed in the state-of-the-art chips design. The latter is not compatible with the traditional CMOS technology. Finding a structure both saving area and compatible technology is the most urgent for PD SOI MOSFETs. Recently, we have developed a new structure with extra heavy boron implantation in the source region for PD SOI nMOSFETs. It consumes no extra area and is also compatible with CMOS technology. The device is found to be free of kink effect in simulation, which implies the floating-body effect is greatly suppressed. In addition, the mechanisms of the kink-free, as well as the impact of different implanting conditions are interpreted.

Chen, Jing; Luo, Jiexin; Wu, Qingqing; Chai, Zhan; Huang, Xiaolu; Wei, Xing; Wang, Xi

2012-02-01

29

Predicting Planets in Known Extra-Solar Planetary Systems III: Forming Terrestrial Planets  

E-print Network

Recent results have shown that many of the known extrasolar planetary systems contain regions which are stable for both Earth-mass and Saturn-mass planets. Here we simulate the formation of terrestrial planets in four planetary systems -- 55 Cancri, HD 38529, HD 37124, and HD 74156 -- under the assumption that these systems of giant planets are complete and that their orbits are well-determined. Assuming the giant planets formed and migrated quickly, then terrestrial planets may form from a second generation of planetesimals. In each case, Moon- to Mars-sized planetary embryos are placed in between the giant planets and evolved for 100 Myr. We find that planets form relatively easily in 55 Cnc, with masses up to 0.6 Earth masses and in some cases substantial water contents and orbits in the habitable zone. HD 38529 is likely to support an asteroid belt but no terrestrial planets of significant mass. No terrestrial planets form in HD 37124 and HD 74156, although in some cases 1-2 lone embryos survive for 100 Myr. If migration occurred later, depleting the planetesimal disk, then massive terrestrial planets are unlikely to form in any of these systems.

Sean N. Raymond; Rory Barnes; Nathan A. Kaib

2006-05-15

30

An observational signature of evolved oceans on extra-solar terrestrial planets  

E-print Network

The increase in luminosity with time of a main sequence star eventually can lead to substantial evaporation of the oceans on an orbiting terrestrial planet. Subsequently, the gas phase water in the planet's upper atmosphere can be photodissociated by stellar ultraviolet and the resulting atomic hydrogen then may be lost in a wind. This gaseous envelope may pass in front of the host star and produce tansient, detectable ultraviolet absorption in the Lyman lines in systems older than 1 Gyr.

M. Jura

2004-02-25

31

Estimating terrestrial amphibian pesticide body burden through dermal exposure  

EPA Science Inventory

Dermal exposure presents a potentially significant but understudied route for pesticide uptake in terrestrial amphibians. Our study measured dermal uptake of pesticides of varying hydrophobicity (logKow) in frogs. Amphibians were indirectly exposed to one of five pesticide active...

32

Strategic considerations in SETI, and a microwave approach. [Search for ExtraTerrestrial Intelligence  

NASA Technical Reports Server (NTRS)

Plausible options in the search for extraterrestrial intelligence (SETI), and the need to reserve a suitable portion of the EM (microwave) spectrum for SETI research, are discussed. Reasons for selection of a portion of the spectrum, specifically the 'water hole' near 1.5 GHz in the terrestrial microwave window (1-25 GHz), are presented, and competition with various emitters for that band (existing satellite downlink transmissions) is discussed. SETI search policies and options are summarized in a table. Speculative considerations guiding initial phases of the SETI pursuit are discussed.

Seeger, C. L.

1977-01-01

33

Extra-terrestrial life in the European Space Agency's Cosmic Vision plan and beyond.  

PubMed

Our exciting time allows us to contemplate the moment in the not-too-distant future when we can detect the presence of life on worlds orbiting stars other than our Sun. It will not be easy and will require the development and use of the very latest technologies. It also very probably demands deployment in space of relevant instrumentation in order to carry out these investigations. The European Space Agency has been involved in the studies and development of the required technologies for more than a decade and is currently formulating a roadmap for how to achieve the ultimate detection of signs of life as we know it on terrestrial exoplanets. The major elements of the roadmap consist of the following. First, the search for and detection of terrestrial exoplanets. Here, some progress has been made recently and is reported in this paper. Second, the more and more detailed study of the physical characteristics of such exoplanets. Finally, the search for biomarkers--indicators of biological activity--that can be observed at interstellar distances. The last is probably one of the most difficult problems ever contemplated by observational astronomy. PMID:21220282

Fridlund, Malcolm

2011-02-13

34

Unconventional phases of the alternating-spin Heisenberg chain with extra three-body exchange terms  

NASA Astrophysics Data System (ADS)

The Heisenberg chain with alternating site spins (S,?) = (1, 1/2) defines a realistic prototype model admitting extra isotropic three-body exchange terms which drive the chain into exotic quantum phases. In this paper, we focus on the non-magnetic part of the phase diagram. Based on numerical density-matrix renormalization group and exact-diagonalization calculations, we demonstrate that the nearest-neighbor three-body interaction stabilizes (i) a critical spin liquid phase described by two Gaussian conformal theories as well as (ii) a critical nematic-like phase characterized by dominant quadrupolar S-spin fluctuations. The emergence of these phases reflects some specific features of the three-body terms such as the promotion of local collinear spin configurations and the enhanced tendency towards nearest- neighbor clustering of the spins.

Ivanov, N. B.; Schnack, J.

2014-12-01

35

Warming-induced reductions in body size are greater in aquatic than terrestrial species  

PubMed Central

Most ectothermic organisms mature at smaller body sizes when reared in warmer conditions. This phenotypically plastic response, known as the “temperature-size rule” (TSR), is one of the most taxonomically widespread patterns in biology. However, the TSR remains a longstanding life-history puzzle for which no dominant driver has been found. We propose that oxygen supply plays a central role in explaining the magnitude of ectothermic temperature-size responses. Given the much lower oxygen availability and greater effort required to increase uptake in water vs. air, we predict that the TSR in aquatic organisms, especially larger species with lower surface area–body mass ratios, will be stronger than in terrestrial organisms. We performed a meta-analysis of 1,890 body mass responses to temperature in controlled experiments on 169 terrestrial, freshwater, and marine species. This reveals that the strength of the temperature-size response is greater in aquatic than terrestrial species. In animal species of ?100 mg dry mass, the temperature-size response of aquatic organisms is 10 times greater than in terrestrial organisms (?5.0% °C?1 vs. ?0.5% °C?1). Moreover, although the size response of small (<0.1 mg dry mass) aquatic and terrestrial species is similar, increases in species size cause the response to become increasingly negative in aquatic species, as predicted, but on average less negative in terrestrial species. These results support oxygen as a major driver of temperature-size responses in aquatic organisms. Further, the environment-dependent differences parallel latitudinal body size clines, and will influence predicted impacts of climate warming on food production, community structure, and food-web dynamics. PMID:23129645

Forster, Jack; Hirst, Andrew G.; Atkinson, David

2012-01-01

36

Phylogenetic comparative methods and the geographic range size – body size relationship in new world terrestrial carnivora  

Microsoft Academic Search

Most recent papers avoid describing macroecological relationships and interpreting then without a previous control of non-independence in data caused by phylogenetic patterns in data. In this paper, we analyzed the geographic range size – body size relationship for 70 species of New World terrestrial Carnivora (‘fissipeds’) using various phylogenetic comparative methods and simulation procedures to assess their statistical performance. Autocorrelation

José Alexandre Felizola Diniz-Filho; Natália Mundim Tôrres

2002-01-01

37

Wet tropospheric delay spatial variability over terrestrial water bodies  

NASA Astrophysics Data System (ADS)

Among the sources of uncertainty in radar altimetry measurements of inland water bodies is the signal delay associated with space-time variations in water vapor in the atmosphere. Over the ocean, zenith wet tropospheric path delays (PD) can be measured by satellite microwave radiometry; however, the high brightness temperature of land prevents the use of these techniques over inland waters. SAR-based Atmospheric Phase Screens can be estimated over land, but not over water bodies. Radiosonde- and GPS-based estimates of PD over land are available, yet these measurements occur at specific, sparse locations. Atmospheric models are therefore the best source of information about space-time variations in PD, where observations (e.g., from radiosonde and GPS) are incorporated via data assimilation. The upcoming Surface Water and Ocean Topography mission (SWOT) will use Interferometric Synthetic Aperture Radar (InSAR) in Ka-band, at a high incidence angle, to measure temporal variations in water elevation, slope, and extent in rivers, lakes, and reservoirs. Images will be collected over a 120-km wide swath with <100 m spatial resolution and ~1 cm height precision when averaged over a 1 km2 area, with a 21-day repeat cycle. At present, the spatial and temporal variability of PD at spatial scales relevant to the mission's inland water objectives (e.g., measurement of variations in the storage of reservoirs and lakes with spatial extent order 1 sq. km and larger) is an open question. We report the results of simulations of PD based on simulations from the Weather Research and Forecasting (WRF) numerical weather prediction model. We consider two domains within the continental U.S.: 1) the Pacific Northwest (at 4-km and 4/3-km spatial resolutions, via WRF results provided by the Northwest Modeling Consortium), and 2) sections of New Mexico, Oklahoma, and Texas (at 2.33-km spatial resolution, via simulations performed for this study). We then investigate the spatial and temporal variability of these PD values over inland water bodies, with a focus on manmade reservoirs in the Western U.S., including Anderson Ranch, Ray Hubbard, Elephant Butte, Lake Mead, and Sam Rayburn. We also assess the degree of temporal correlation between PD and water level variations and spatial correlations between PD and water extent variations.

Clark, E.; Moller, D.; Andreadis, K.; Lettenmaier, D. P.

2013-12-01

38

Elucidating differences in metal absorption efficiencies between terrestrial soft-bodied and aquatic species.  

PubMed

It is unknown whether metal absorption efficiencies in terrestrial soft-bodied species can be predicted with the same metal properties as for aquatic species. Here, we developed models for metal absorption efficiency from the dissolved phase for terrestrial worms and several aquatic species, based on 23 metal physicochemical properties. For the worms, the absorption efficiency was successfully related to 7 properties, and is best predicted with the ionic potential. Different properties (8 in total) were found to be statistically significant in regressions predicting metal absorption in aquatic species, with the covalent index being the best predictor. It is hypothesized that metal absorption by soft-bodied species in soil systems is influenced by the rate of metal supply to the membrane, while in aquatic systems accumulation is solely determined by metal affinity to membrane bound transport proteins. Our results imply that developing predictive terrestrial bioaccumulation and toxicity models for metals must consider metal interactions with soil solids. This may include desorption of a cation bound to soil solids through ion exchange, or metal release from soil surfaces involving breaking of metal-oxygen bonds. PMID:25048944

Owsianiak, Miko?aj; Veltman, Karin; Hauschild, Michael Z; Hendriks, A Jan; Steinmann, Zoran J N; Huijbregts, Mark A J

2014-10-01

39

Molecular phylogeny of selected predaceous leeches with reference to the evolution of body size and terrestrialism.  

PubMed

The phylogenetic relationships of erpobdellid leeches collected throughout Europe were investigated using newly obtained mitochondrial cytochrome c oxidase subunit I (CO-I) gene sequence data from 10 taxa. Monophyly of the five European Erpobdella species (sub-family Erpobdellinae) was supported, but a newly discovered leech, E. wuttkei Kutschera, 2004 (the smallest member of its genus, discovered in an aquarium) was only distantly related to this clade. Three members of the semiaquatic Trochetinae were included in this study. The largest European leech species discovered so far, Trocheta haskonis Grosser, 2000, was found to be a terrestrial predator that feeds on earthworms. The rare species T. haskonis is the sister taxon of T. bykowskii Gedroyc, 1913, a well-known amphibious leech. Based on a comparison of body sizes and a phylogenetic tree the evolution of terrestrialism in the family Erpobdellidae is discussed. PMID:17046348

Pfeiffer, I; Brenig, B; Kutschera, U

2005-08-01

40

LINEAR ALLOMETRIC RELATIONSHIP BETWEEN TOTAL METABOLIC ENERGY PER LIFE SPAN AND BODY MASS OF TERRESTRIAL MAMMALS IN CAPTIVITY  

Microsoft Academic Search

Summary Atanasov, A.T., 2006. Linear allometric relationship between total metabolic energy per life span and body mass of terrestrial mammals in captivity. Bulg. J. Vet. Med. , 9, No 3, 159 ?174. The bioenergetic studies on animals have shown that basal metabolic rate P (kJ\\/d), is related to the body mass M (kg) of animals as expressed by the equation:

A. T. Atanasov

2006-01-01

41

Terrestrial impact craters: Their spatial and temporal distribution and impacting bodies  

Microsoft Academic Search

The terrestrial impact record contains currently ~145 structures and includes the morphological crater types observed on the other terrestrial planets. It has, however, been severely modified by terrestrial geologic processes and is biased towards young ( 200 Ma) and large ( 20 km) impact structures on relatively well-studied cratonic areas. Nevertheless, the ground-truth data available from terrestrial impact structures have

Richard A. F. Grieve; Lauri J. Pesonen

1996-01-01

42

Body mass estimation in xenarthra: a predictive equation suitable for all quadrupedal terrestrial placentals?  

PubMed

The Magnorder Xenarthra includes strange extinct groups, like glyptodonts, similar to large armadillos, and ground sloths, terrestrial relatives of the extant tree sloths. They have created considerable paleobiological interest in the last decades; however, the ecology of most of these species is still controversial or unknown. The body mass estimation of extinct species has great importance for paleobiological reconstructions. The commonest way to estimate body mass from fossils is through linear regression. However, if the studied species does not have similar extant relatives, the allometric pattern described by the regression could differ from those shown by the extinct group. That is the case for glyptodonts and ground sloths. Thus, stepwise multiple regression were developed including extant xenarthrans (their taxonomic relatives) and ungulates (their size and ecological relatives). Cases were weighted to maximize the taxonomic evenness. Twenty-eight equations were obtained. The distribution of the percent of prediction error (%PE) was analyzed between taxonomic groups (Perissodactyla, Artiodactyla, and Xenarthra) and size groups (0-20 kg, 20-300 kg, and more than 300 kg). To assess the predictive power of the functions, equations were applied to species not included in the regression development [test set cross validation, (TSCV)]. Only five equations had a homogeneous %PE between the aforementioned groups. These were applied to five extinct species. A mean body mass of 80 kg was estimated for Propalaehoplophorus australis (Cingulata: Glyptodontidae), 594 kg for Scelidotherium leptocephalum (Phyllophaga: Mylodontidae), and 3,550.7 kg for Lestodon armatus (Phyllophaga: Mylodontidae). The high scatter of the body mass estimations obtained for Catonyx tarijensis (Phyllophaga: Mylodontidae) and Thalassocnus natans (Phyllophaga: Megatheriidae), probably due to different specializations, prevented us from predicting its body mass. Surprisingly, although obtained from ungulates and xenarthrans, these five selected equations were also able to predict the body mass of species from groups as different as rodents, carnivores, hyracoideans, or tubulidentates. This result suggests the presence of a complex common allometric pattern for all quadrupedal placentals. PMID:18655156

De Esteban-Trivigno, Soledad; Mendoza, Manuel; De Renzi, Miquel

2008-10-01

43

Body mass explains characteristic scales of habitat selection in terrestrial mammals  

PubMed Central

Niche theory in its various forms is based on those environmental factors that permit species persistence, but less work has focused on defining the extent, or size, of a species’ environment: the area that explains a species’ presence at a point in space. We proposed that this habitat extent is identifiable from a characteristic scale of habitat selection, the spatial scale at which habitat best explains species’ occurrence. We hypothesized that this scale is predicted by body size. We tested this hypothesis on 12 sympatric terrestrial mammal species in the Canadian Rocky Mountains. For each species, habitat models varied across the 20 spatial scales tested. For six species, we found a characteristic scale; this scale was explained by species’ body mass in a quadratic relationship. Habitat measured at large scales best-predicted habitat selection in both large and small species, and small scales predict habitat extent in medium-sized species. The relationship between body size and habitat selection scale implies evolutionary adaptation to landscape heterogeneity as the driver of scale-dependent habitat selection. PMID:22393519

Fisher, Jason T; Anholt, Brad; Volpe, John P

2011-01-01

44

The Galactic Exoplanet Survey Telescope: A Proposed Space-Based Microlensing Survey for Terrestrial Extra-Solar Planets  

E-print Network

We present a conceptual design for a space based Galactic Exoplanet Survey Telescope (GEST) which will use the gravitational microlensing technique to detect extra solar planets with masses as low as that of Mars at all separations >~ 1 AU. The microlensing data would be collected by a diffraction limited, wide field imaging telescope of ~ 1.5m aperture equipped with a large array of red-optimized CCD detectors. Such a system would be able to monitor $\\sim 2\\times 10^8$ stars in $\\sim 6$ square degrees of the Galactic bulge at intervals of 20-30 minutes, and it would observe $\\sim 12000$ microlensing events in three bulge seasons. If planetary systems like our own are common, GEST should be able to detect $\\sim 5000$ planets over a 2.5 year lifetime. If gas giants like Jupiter and Saturn are rare, then GEST would detect $\\sim 1300$ planets in a 2.5 year mission if we assume that most planetary systems are dominated by planets of about Neptune's' mass. Such a mission would also discover $\\sim 100$ planets of an Earth mass or smaller if such planets are common. This is a factor of $\\sim 50$ better than the most ambitious ground based programs that have been proposed. GEST will also be sensitive to planets which have been separated from their parent stars.

David P. Bennett; Sun Hong Rhie

2000-03-08

45

Syntax diagrams for body wave nomenclature, with generalizations for terrestrial planets  

NASA Astrophysics Data System (ADS)

The Apollo network on the Moon constitutes the beginning of planetary seismology. In the next few decades, we may see seismometers deployed on the Moon again, on Mars, and perhaps on other terrestrial planets or satellites. Any seismological software for computation of body wave travel times on other planets should be highly versatile and be prepared for a huge variety of velocity distributions and internal structures. A suite of trial models for a planet might, for example, contain models with and without solid inner cores. It would then be useful if the software could detect physically meaningless phase names automatically without actually carrying out any computation. It would also be useful if the program were prepared to deal with features like fully solid cores, internal oceans, and varying depths of mineralogical phase changes like the olivine-spinel transition. Syntax diagrams are a standard method to describe the syntax of programming languages. They represent a graphical way to define which letter or phrase is allowed to follow a given sequence of letters. Syntax diagrams may be stored in data structures that allow automatic evaluation of a given letter sequence. Such diagrams are presented here for a generalized body wave nomenclature. Generalizations are made to overcome earth-specific notations which incorporate discontinuity depths into phase names or to distinguish olivine transitions from ice-ice transitions (as expected on the Galilean Satellites).

Knapmeyer, M.

2003-04-01

46

Dynamics of the terrestrial planets from a large number of N-body simulations  

NASA Astrophysics Data System (ADS)

The agglomeration of planetary embryos and planetesimals was the final stage of terrestrial planet formation. This process is modeled using N-body accretion simulations, whose outcomes are tested by comparing to observed physical and chemical Solar System properties. The outcomes of these simulations are stochastic, leading to a wide range of results, which makes it difficult at times to identify the full range of possible outcomes for a given dynamic environment. We ran fifty high-resolution simulations each with Jupiter and Saturn on circular or eccentric orbits, whereas most previous studies ran an order of magnitude fewer. This allows us to better quantify the probabilities of matching various observables, including low probability events such as Mars formation, and to search for correlations between properties. We produce many good Earth analogues, which provide information about the mass evolution and provenance of the building blocks of the Earth. Most observables are weakly correlated or uncorrelated, implying that individual evolutionary stages may reflect how the system evolved even if models do not reproduce all of the Solar System's properties at the end. Thus individual N-body simulations may be used to study the chemistry of planetary accretion as particular accretion pathways may be representative of a given dynamic scenario even if that simulation fails to reproduce many of the other observed traits of the Solar System.

Fischer, Rebecca A.; Ciesla, Fred J.

2014-04-01

47

Phase diagram of the alternating-spin Heisenberg chain with extra isotropic three-body exchange interactions  

NASA Astrophysics Data System (ADS)

For the time being isotropic three-body exchange interactions are scarcely explored and mostly used as a tool for constructing various exactly solvable one-dimensional models, although, generally speaking, such competing terms in generic Heisenberg spin systems can be expected to support specific quantum effects and phases. The Heisenberg chain constructed from alternating S = 1 and ? = 1/2 site spins defines a realistic prototype model admitting extra three-body exchange terms. Based on numerical density-matrix renormalization group (DMRG) and exact diagonalization (ED) calculations, we demonstrate that the additional isotropic three-body terms stabilize a variety of partially-polarized states as well as two specific non-magnetic states including a critical spin-liquid phase controlled by two Gaussinal conformal theories as well as a critical nematic-like phase characterized by dominant quadrupolar S-spin fluctuations. Most of the established effects are related to some specific features of the three-body interaction such as the promotion of local collinear spin configurations and the enhanced tendency towards nearest-neighbor clustering of the spins. It may be expected that most of the predicted effects of the isotropic three-body interaction persist in higher space dimensions.

Ivanov, Nedko B.; Ummethum, Jörg; Schnack, Jürgen

2014-10-01

48

Influence of Water Availability during Incubation on Hatchling Size, Body Composition, Desiccation Tolerance, and Terrestrial  

E-print Network

, Desiccation Tolerance, and Terrestrial Locomotor Performance in the Snapping Turtle Chelydra serpentina incubation has been examined extensively, es- pecially in the common snapping turtle, Chelydra serpentina

Finkler, Michael S.

49

ENERGETICS AND MECHANICS OF TERRESTRIAL LOCOMOTION I. METABOLIC ENERGY CONSUMPTION AS A FUNCTION OF SPEED AND BODY SIZE IN BIRDS AND MAMMALS  

Microsoft Academic Search

SUMMARY This series of four papers investigates the link between the energetics and the mechanics of terrestrial locomotion. Two experimental variables are used throughout the study: speed and body size. Mass-specific metabolic rates of running animals can be varied by about tenfold using either variable. This first paper considers metabolic energy consumed during terrestrial locomotion. New data relating rate of

C. R. TAYLOR; N. C. HEGLUND; G. M. O. MALOIY

50

Hydrometric Area Local Authority Associated surface water bodies Associated terrestrial ecosystems  

Microsoft Academic Search

Topography This groundwater body is elongate in plan view, and includes several different topographic areas. In the south the Barrow River flows down the centre of the body from New Ross to Borris. Here the river has upland areas on both sides, the Blackstairs Mountains to the east and Brandon Hill at 575m OD to the west. North of Borris

Corballis Hill

51

Influences of limb proportions and body size on locomotor kinematics in terrestrial primates and fossil hominins.  

PubMed

During locomotion, mammalian limb postures are influenced by many factors including the animal's limb length and body mass. Polk (2002) compared the gait of similar-sized cercopithecine monkeys that differed limb proportions and found that longer-limbed monkeys usually adopt more extended joint postures than shorter-limbed monkeys in order to moderate their joint moments. Studies of primates as well as non-primate mammals that vary in body mass have demonstrated that larger animals use more extended limb postures than smaller animals. Such extended postures in larger animals increase the extensor muscle mechanical advantage and allow postures to be maintained with relatively less muscular effort (Polk, 2002; Biewener 1989). The results of these previous studies are used here to address two anthropological questions. The first concerns the postural effects of body mass and limb proportion differences between australopithecines and members of the genus Homo. That is, H. erectus and later hominins all have larger body mass and longer legs than australopithecines, and these anatomical differences suggest that Homo probably used more extended postures and probably required relatively less muscular force to resist gravity than the smaller and shorter-limbed australopithecines. The second question investigates how animals with similar size but different limb proportions differ in locomotor performance. The effects of limb proportions on gait are relevant to inferring postural and locomotor differences between Neanderthals and modern Homo sapiens which differ in their crural indices and relative limb length. This study demonstrates that primates with relatively long limbs achieve higher walking speeds while using lower stride frequencies and lower angular excursions than shorter-limbed monkeys, and these kinematic differences may allow longer-limbed taxa to locomote more efficiently than shorter-limbed species of similar mass. Such differences may also have characterized the gait of Homo sapiens in comparison to Neanderthals, but more experimental data on humans that vary in limb proportions are necessary in order to evaluate this question more thoroughly. PMID:15454335

Polk, J D

2004-10-01

52

Diet Effect Study On Terrestrial Snail Body Tissues and Shell Carbonates In Experimental Conditions: Applications To Paleoenvironments  

NASA Astrophysics Data System (ADS)

The isotopic analysis of different materials yielded original elements to understanding the ecosystems and the paleoenvironments. Although most of the studies on fossil material was interpreted through the modern conditions at the vicinity of the fossil record, no precise analysis of the impact of the diet and precipitation was carried out in order to justify such assumptions. Here we present the results of the influence of diet and water on the carbone and oxygen isotope compositions of the body tissues and shell aragonite of terrestrial mollusk shells, a particularly accurate climate indicator. Our experiment consists of individuals from hatched eggs of Helix aspersa raised in our laboratory. Three groups of snails were fed on lettuce (C3 plant), corn (C4 plant) and mixed diet (C3+C4). They were sprayed at the same time with 3 different water in order to estimate the influence of continental effect. To estimate the paleotemperature changes, the hatched snails groups were placed in three rooms adjusted automatically to different temperatures. The experimental results indicate that the d13C of the shells is a good record of the isotopic composition of the snail body tissue, and therefore a good record of diet, and the d18O a good record of precipitations in relation with temperature change.

Metref, S.; Rousseau, D.-D.; Bentaleb, I.; Labonne, M.; Vianey-Liaud, M.; Moussa, I.

53

Ultrastructural analysis of the dorsal body gland of the terrestrial snail Megalobulimus abbreviatus (Becquaert, 1948).  

PubMed

The ultrastructure of the reproductive gland, dorsal body (DB), of Megalobulimus abbreviatus was analysed. Electron microscope immunohistochemistry was used to detect FMRFamide-like peptides in the nerve endings within this gland. Nerve backfilling was used in an attempt to identify the neurons involved in this innervation. In M. abbreviatus, the DB has a uniform appearance throughout their supraesophageal and subesophageal portions. Dorsal body cells have several features in common with steroid-secreting gland cells, such as the presence of many lipid droplets, numerous mitochondria with tubular cristae and a developed smooth endoplasmic reticulum cisternae. Throughout the DB in M. abbreviatus numerous axonal endings were seen to be in contact with the DB cells exhibiting a synaptic-like structure. The axon terminals contained numerous electron-dense and scanty electron-lucid vesicles. In addition, the DB nerve endings exhibited FMRFamide immunoreactive vesicles. Injection of neural tracer into the DB yielded retrograde labelling of neurons in the metacerebrum lobe of the cerebral ganglia and in the parietal ganglia of the subesophageal ganglia complex. The possibility that some of these retrograde-labelled neurons might be FMRFamide-like neurons that may represent a neural control to the DB in M. abbreviatus is discussed. PMID:20379650

Moraes, G D; Achaval, M; Dal Piva, M M; Faccioni-Heuser, M C; Wassermann, G F; Zancan, D M

2010-05-01

54

An interesting journey of an ingested needle: a case report and review of the literature on extra-abdominal migration of ingested foreign bodies.  

PubMed

Swallowed foreign bodies encounter a major problem especially in children, but fortunately they mostly do not cause any related complication and are easily passed with the stool. In this paper, an interesting journey of a needle is presented. A 20-year old female admitted to our emergency service after she had swallowed a sewing machine needle, which is initially observed in the stomach in the plain abdominal radiography. During the follow-up period, the needle traveled through bowels, and surprisingly was observed in the left lung on 10th day of the follow-up. It was removed with a thoracotomy and pneumotomy under the fluoroscopic guidance. The postoperative period was uneventful and the patient was discharged from the hospital on the day 5. We also review the literature on interesting extra-abdominal migrations of swallowing foreign bodies. PMID:21615959

Ozkan, Zeynep; Kement, Metin; Karg?, Ahmet B; Censur, Zafer; Gezen, Fazli C; Vural, Selahattin; Oncel, Mustafa

2011-01-01

55

U-Pb Composition and Shock Microstructures of In-Situ Accessory Phases Across the Vredefort Impact Structure, South Africa: A Terrestrial Analogue for Dating the Lunar Surface and Other Planetary Bodies  

NASA Astrophysics Data System (ADS)

Accessory phases (i.e. zircon, monazite) co-exist within individual samples of the Vredefort dome, with a dichotomy of U-Pb ages and microstructural evolution. Vredefort is a terrestrial analogue for complex craters on other planetary bodies.

Davis, C. L.; Moser, D. E.

2015-02-01

56

Direct Detection of Extra-Solar Comets is Possible  

E-print Network

The dust tails of comets similar to Hale-Bopp can scatter as much optical light as does the Earth. Space-based observatories such as the Terrestrial Planet Finder or Darwin that will detect extra-solar terrestrial planets also will be able to detect extra-solar comets.

M. Jura

2005-05-24

57

Dynamical Shakeup of Planetary Systems II. N-body simulations of Solar System terrestrial planet formation induced by secular resonance sweeping  

E-print Network

We revisit the "dynamical shakeup" model of Solar System terrestrial planet formation, wherein the whole process is driven by the sweeping of Jupiter's secular resonance as the gas disk is removed. Using a large number of 0.5 Gyr-long N-body simulations, we investigate the different outcomes produced by such a scenario. We confirm that in contrast to existing models, secular resonance sweeping combined with tidal damping by the disk gas can reproduce the low eccentricities and inclinations, and high radial mass concentration, of the Solar System terrestrial planets. At the same time, this also drives the final assemblage of the planets on a timescale of several tens of millions of years, an order of magnitude faster than inferred from previous numerical simulations which neglected these effects, but possibly in better agreement with timescales inferred from cosmochemical data. In addition, we find that significant delivery of water-rich material from the outer Asteroid Belt is a natural byproduct.

E. W. Thommes; M. Nagasawa; D. N. C. Lin

2008-02-05

58

On the rise of turbulent plumes: Quantitative effects of variable entrainment for submarine hydrothermal vents, terrestrial  

E-print Network

hydrothermal vents, terrestrial and extra terrestrial explosive volcanism G. Carazzo,1 E. Kaminski,1 and S: Quantitative effects of variable entrainment for submarine hydrothermal vents, terrestrial and extra terrestrial, paleo-Martian, and Venusian conditions and by submarine hydrothermal activity at mid-ocean ridges

Kaminski, Edouard

59

Searching for extra-terrestrial civilizations  

NASA Technical Reports Server (NTRS)

The probability of radio interchange with extraterrestrial civilizations is discussed. Difficulties constitute absorption, scattering, and dispersion of signals by the rarified interstellar medium as well as the deciphering of received signals and convergence of semantic concept. A cybernetic approach considers searching for signals that develop from astroengineering activities of extraterrestrial civilizations.

Gindilis, L. M.

1974-01-01

60

The Search for Extra-Terrestrial Intelligence  

NASA Astrophysics Data System (ADS)

Aliens abound on the movie screens, but in reality we are still trying to find out if we share our universe with other sentient creatures. Intelligence is very difficult to define, and impossible to directly detect over interstellar distances. Therefore, SETI, the search for extraterrestrial intelligence, is actually an attempt to detect evidence of another distant technology. If we find such evidence, we will infer the existence of intelligent technologists. For the past 36 years, the SETI community has had a very pragmatic definition of intelligence - the ability to build radio telescopes! Radio signals are not the only possible way to detect a technology across the vast distances that separate the stars, but given our own current technological state, it remains the best way.

Tarter, J.

1998-12-01

61

The Search for ExtraTerrestrial Intelligence  

Microsoft Academic Search

Aliens abound on the movie screens, but in reality we are still trying to find out if we share our universe with other sentient creatures. Intelligence is very difficult to define, and impossible to directly detect over interstellar distances. Therefore, SETI, the search for extraterrestrial intelligence, is actually an attempt to detect evidence of another distant technology. If we find

J. Tarter

1998-01-01

62

ON THE EFFECT OF GIANT PLANETS ON THE SCATTERING OF PARENT BODIES OF IRON METEORITE FROM THE TERRESTRIAL PLANET REGION INTO THE ASTEROID BELT: A CONCEPT STUDY  

SciTech Connect

In their model for the origin of the parent bodies of iron meteorites, Bottke et al. proposed differentiated planetesimals, formed in 1-2 AU during the first 1.5 Myr, as the parent bodies, and suggested that these objects and their fragments were scattered into the asteroid belt as a result of interactions with planetary embryos. Although viable, this model does not include the effect of a giant planet that might have existed or been growing in the outer regions. We present the results of a concept study where we have examined the effect of a planetary body in the orbit of Jupiter on the early scattering of planetesimals from the terrestrial region into the asteroid belt. We integrated the orbits of a large battery of planetesimals in a disk of planetary embryos and studied their evolutions for different values of the mass of the planet. Results indicate that when the mass of the planet is smaller than 10 M{sub Circled-Plus }, its effects on the interactions among planetesimals and planetary embryos are negligible. However, when the planet mass is between 10 and 50 M{sub Circled-Plus }, simulations point to a transitional regime with {approx}50 M{sub Circled-Plus} being the value for which the perturbing effect of the planet can no longer be ignored. Simulations also show that further increase of the mass of the planet strongly reduces the efficiency of the scattering of planetesimals from the terrestrial planet region into the asteroid belt. We present the results of our simulations and discuss their possible implications for the time of giant planet formation.

Haghighipour, Nader [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States); Scott, Edward R. D., E-mail: nader@ifa.hawaii.edu [Hawaii Institute for Geophysics and Planetology, University of Hawaii-Manoa, Honolulu, HI 96822 (United States)

2012-04-20

63

Enrichment of Non-Terrestrial L-Proteinogenic Amino Acids by Aqueous Alteration on the Tagish Lake Meteorite Parent Body  

NASA Technical Reports Server (NTRS)

The distribution and isotopic and enantiomeric compositions of amino acids found in three distinct fragments of the Tagish Lake C2-type carbonaceous chondrite were investigated via liquid chromatography fluorescence detection time-of-flight mass spectrometry and gas chromatography isotope ratio mass spectrometry. Large L-enantiomeric excesses (L(sub ee) approx. 43 to 59%) of the a-hydrogen aspartic and glutamic amino acids were measured in Tagish Lake, whereas alanine, another alpha-hydrogen protein amino acid, was found to be nearly racemic (D approx. L) using both techniques. Carbon isotope measurements of D- and L-aspartic acid and D- and L-alanine in Tagish Lake fall well outside of the terrestrial range and indicate that the measured aspartic acid enantioenrichment is indigenous to the meteorite. Alternate explanations for the Lexcesses of aspartic acid such as interference from other compounds present in the sample, analytical biases, or terrestrial amino acid contamination were investigated and rejected. These results can be explained by differences in the solid-solution phase behavior of aspartic acid, which can form conglomerate enantiopure solids during crystallization, and alanine, which can only form racemic crystals.

Glavin, Daniel P.; Elsila, Jamie E.; Burton, Aaron S.; Callahan, Michael P.; Dworkin, Jason P.; Herd, Christopher D. K.

2012-01-01

64

Super-long Anabiosis of Ancient Microorganisms in Ice and Terrestrial Models for Development of Methods to Search for Life on Mars, Europa and other Planetary Bodies  

NASA Technical Reports Server (NTRS)

Successful missions to Mars, Europe and other bodies of the Solar system have created a prerequisite to search for extraterrestrial life. The first attempts of microbial life detection on the Martian surface by the Viking landed missions gave no biological results. Microbiological investigations of the Martian subsurface ground ice layers seem to be more promising. It is well substantiated to consider the Antarctic ice sheet and the Antarctic and Arctic permafrost as terrestrial analogues of Martian habitats. The results of our long-standing microbiological studies of the Antarctic ice would provide the basis for detection of viable microbial cells on Mars. Our microbiological investigations of the deepest and thus most ancient strata of the Antarctic ice sheet for the first time gave evidence for the natural phenomenon of long-term anabiosis (preservation of viability and vitality for millennia years). A combination of classical microbiological methods, epifluorescence microscopy, SEM, TEM, molecular diagnostics, radioisotope labeling and other techniques made it possible for us to obtain convincing proof of the presence of pro- and eukaryotes in the Antarctic ice sheet. In this communication, we will review and discuss some critical issues related to the detection of viable microorganisms in cold terrestrial environments with regard to future searches for microbial life and/or its biological signatures on extraterrestrial objects.

Abyzov, S. S.; Duxbury, N. S.; Bobin, N. E.; Fukuchi, M.; Hoover, R. B.; Kanda, H.; Mitskevich, I. N.; Mulyukin, A. L.; Naganuma, T.; Poglazova, M. N.; Ivanov, M. V.

2007-01-01

65

Quantifying The Impact of Extra-Nasal Testing Body Sites for MRSA Colonization at the Time of Hospital or Intensive Care Unit Admission  

PubMed Central

Objective Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of healthcare-associated infections. Recent legislative mandates require nares screening for MRSA at hospital and ICU admission in many states. However, MRSA colonization at extra-nasal sites is increasingly recognized. We conducted a systematic review of the literature to identify the yield of extra-nasal testing for MRSA. Design We searched MEDLINE from January 1966 through January 2012 for articles comparing nasal and extra-nasal screening for MRSA colonization. Studies were categorized by population tested, specifically those admitted to ICUs, and those admitted to hospitals with a high prevalence (?6%) or low prevalence (<6%) of MRSA carriers. Data were extracted using a standardized instrument. Results We reviewed 4,381 abstracts and 735 manuscripts. Twenty-three manuscripts met criteria for analysis (n=39,479 patients). Extra-nasal MRSA screening increased yield by approximately one-third over nares alone. The yield was similar upon ICU admission (weighted average 33%, range 9%–69%), and hospital admission in high (weighted average 37%, range 9–86%) and low prevalence (weighted average 50%, range 0–150%) populations. Comparing individual extra nasal sites, testing the oropharynx increased MRSA detection by 21% over nares alone; rectum by 20%; wounds by 17%; and axilla by 7%. Conclusions Extra-nasal MRSA screening at hospital or ICU admission in adults will increase MRSA detection by one-third compared to nares screening alone. Findings were consistent among subpopulations examined. Extra-nasal testing may be a valuable strategy for outbreak control or in settings of persistent disease, particularly when combined with decolonization or enhanced infection prevention protocols. PMID:23295562

McKinnell, James A.; Huang, Susan S.; Eells, Samantha J.; Cui, Eric; Miller, Loren G.

2013-01-01

66

Effects of Norepinephrine and Epinephrine on Resting Membrane Potential in Body Wall Muscle Cells of Lumbricus Terrestris Eearthworm  

Microsoft Academic Search

Norepinephrine and to a lesser extent epinephrine increased the resting membrane potential of earthworm body wall muscle cells. Ouabain, phentolamine, propranolol, and replacement of Ca2+ with Mg2+ in the incubation medium abolished this effect. External 3'5'-cAMP in high concentration, dibutyryl cAMP, and dibutyryl cGMP did not induced hyperpolarization of muscle cell membranes. It was concluded that norepinephrine and epinephrine increased

E. M. Volkov; L. F. Nurullin; E. E. Nikol'skii; G. I. Blokhina

2001-01-01

67

Siderophile-element Anomalies in CK Carbonaceous Chondrites: Implications for Parent-body Aqueous Alteration and Terrestrial Weathering of Sulfides  

NASA Technical Reports Server (NTRS)

CK chondrites constitute the most oxidized anhydrous carbonaceous chondrite group; most of the Fe occurs in magnetite and in FeO-rich mafic silicates. The two observed CK falls (Karoonda and Kobe), along with thirteen relatively unweathered CK finds, have unfractionated siderophile-element abundance patterns. In contrast, a sizable fraction of CK finds (9 of 24 investigated) shows fractionated siderophile abundance patterns including low abundances of Ni, Co, Se and Au; the most extreme depletions are in Ni (0.24 of normal CK) and Au (0.14 of normal CK). This depletion pattern has not been found in other chondrite groups. Out of the 74 CK chondrites listed in the Meteoritical Bulletin Database (2006; excluded considerably paired specimens; see http://tin.er.usgs.gov/meteor/ metbull.php) we analyzed 24 and subclassified the CK chondrites in terms of their chemical composition and sulfide mineralogy: sL (siderophiles low; six samples) for large depletions in Ni, Co, Se and Au (>50% of sulfides lost); sM (siderophiles medium; two CKs) for moderately low Ni and Co abundances (sulfides are highly altered or partly lost); sH (siderophiles high; one specimen) for enrichments in Ni, Co, Se and Au; 'normal' for unfractionated samples (13 samples). The sole sH sample may have obtained additional sulfide from impact redistribution in the parent asteroid. We infer that these elements became incorporated into sulfides after asteroidal aqueous processes oxidized nebular metal; thermal metamorphism probably also played a role in their mineral siting. The siderophile losses in the SL and sM samples are mainly the result of oxidation of pentlandite, pyrite and violarite by terrestrial alteration followed by leaching of the resulting phases. Some Antarctic CK chondrites have lost most of their sulfides but retained Ni, Co, Se and Au, presumably as insoluble weathering products.

Huber, Heinz; Rubin, Alan E.; Kallemeyn, Gregory W.; Wasson, John T.

2006-01-01

68

Making More Terrestrial Planets  

Microsoft Academic Search

The results of 16 new 3D N-body simulations of the final stage of the formation of the terrestrial planets are presented. These N-body integrations begin with 150–160 lunar-to-Mars size planetary embryos, with semi-major axes 0.3

J. E. Chambers

2001-01-01

69

Terrestrial sequestration  

ScienceCinema

Terrestrial sequestration is the enhancement of CO2 uptake by plants that grow on land and in freshwater and, importantly, the enhancement of carbon storage in soils where it may remain more permanently stored. Terrestrial sequestration provides an opportunity for low-cost CO2 emissions offsets.

Charlie Byrer

2010-01-08

70

Terrestrial sequestration  

SciTech Connect

Terrestrial sequestration is the enhancement of CO2 uptake by plants that grow on land and in freshwater and, importantly, the enhancement of carbon storage in soils where it may remain more permanently stored. Terrestrial sequestration provides an opportunity for low-cost CO2 emissions offsets.

Charlie Byrer

2008-03-10

71

KINEMATIC AND ELECTROMYOGRAPHIC ANALYSIS OF THE FUNCTIONAL ROLE OF THE BODY AXIS DURING TERRESTRIAL AND AQUATIC LOCOMOTION IN THE SALAMANDER AMBYSTOMA TIGRINUM  

Microsoft Academic Search

Summary Aquatic neotenic and terrestrial metamorphosed salamanders {Ambystoma tigrinum) were videotaped simultaneously with electromyographic (EMG) recording from five epaxial myotomes along the animal's trunk during swimming in a flow tank and trotting on a treadmill to investigate axial function during aquatic and terrestrial locomotion. Neotenic and metamorphosed individuals swim using very similar axial wave patterns, despite significant differences in axial

LARRY M. FROLICH; ANDREW A. BIEWENER

1992-01-01

72

Variation of Reproductive Traits and Female Body Size in the Most Widely-Ranging Terrestrial Reptile: Testing the Effects of Reproductive Mode, Lineage, and Climate.  

PubMed

The European common lizard, Zootoca vivipara, is the most widespread terrestrial reptile in the world. It occupies almost the entire Northern Eurasia and includes four viviparous and two oviparous lineages. We analysed how female snout-vent length (SVL), clutch size (CS), hatchling mass (HM), and relative clutch mass (RCM) is associated with the reproductive mode and climate throughout the species range and across the evolutionary lineages within Z. vivipara. The studied variables were scored for 1,280 females and over 3,000 hatchlings from 44 geographically distinct study samples. Across the species range, SVL of reproductive females tends to decrease in less continental climates, whereas CS corrected for female SVL and RCM tend to decrease in climates with cool summer. Both relationships are likely to indicate direct phenotypic responses to climate. For viviparous lineages, the pattern of co-variation between female SVL, CS and HM among populations is similar to that between individual females within populations. Consistent with the hypothesis that female reproductive output is constrained by her body volume, the oviparous clade with shortest retention of eggs in utero showed highest HM, the oviparous clade with longer egg retention showed lower HM, and clades with the longest egg retention (viviparous forms) had lowest HM. Viviparous populations exhibited distinctly lower HM than the other European lacertids of similar female SVL, many of them also displaying unusually high RCM. This pattern is consistent with Winkler and Wallin's model predicting a negative evolutionary link between the total reproductive investment and allocation to individual offspring. PMID:23950617

Roitberg, Evgeny S; Kuranova, Valentina N; Bulakhova, Nina A; Orlova, Valentina F; Eplanova, Galina V; Zinenko, Oleksandr I; Shamgunova, Regina R; Hofmann, Sylvia; Yakovlev, Vladimir A

2013-01-01

73

Climate and Habitability of Terrestrial Planets around other Stars  

E-print Network

extraterrestrial intelligent life directly by looking for radio signals. The ``Search for Extra­Terrestrial@lmd.jussieu.fr). Abstract. The recent discovery of extra­solar giant planets, the quest for extraterrestrial radio Intelligence'' (SETI) programs involve sev­ eral major radio­telescopes around the world. The main SETI project

Forget, François

74

Influence of Water Availability during Incubation on Hatchling Size, Body Composition, Desiccation Tolerance, and Terrestrial Locomotor Performance in the Snapping Turtle [ITAL]Chelydra serpentina[\\/ITAL  

Microsoft Academic Search

The effects of water availability during incubation on the water contents of neonatal snapping turtles at hatching were exam- ined, along with the influence of hatchling water content on desiccation tolerance and terrestrial locomotor performance. The water contents of hatchlings from eggs incubated on wet substrates were both absolutely and proportionally greater than were those of hatchlings from eggs incubated

Michael S. Finkler

1999-01-01

75

Accretion and differentiation of the terrestrial planets with implications for the compositions of early-formed Solar System bodies and accretion  

E-print Network

of early-formed Solar System bodies and accretion of water D.C. Rubie a, , S.A. Jacobson a,b , A Science Institute, 1700 E. Ft. Lowell, Suite 106, Tucson, AZ 85719, USA d Dept. of Earth, Planetary that non-volatile ele- ments are present in Solar System (CI) relative abundances in all bodies

Nimmo, Francis

76

Accumulation of the terrestrial planets  

Microsoft Academic Search

A review is conducted of the current status of theoretical and numerical research on the accumulation of the terrestrial planets. The growth of planets is considered, taking into account the road to rapid accretion and giant protoplanets and the slow road to planetary formation by continual sweeping up of small bodies by larger ones. It is found possible to gain

G. W. Wetherill

1978-01-01

77

Influence of water availability during incubation on hatchling size, body composition, desiccation tolerance, and terrestrial locomotor performance in the snapping turtle Chelydra serpentina.  

PubMed

The effects of water availability during incubation on the water contents of neonatal snapping turtles at hatching were examined, along with the influence of hatchling water content on desiccation tolerance and terrestrial locomotor performance. The water contents of hatchlings from eggs incubated on wet substrates were both absolutely and proportionally greater than were those of hatchlings from eggs incubated on dry substrates. Hatchlings with greater water contents at hatching were able to survive longer and to lose more water before physiological performance was adversely affected by desiccation. Increased water contents in hatchlings with greater water availability during incubation may enhance survival by increasing the amount of water the animal can afford to lose before dehydration begins to adversely affect whole animal performance. PMID:10603335

Finkler, M S

1999-01-01

78

Terrestrial Planet Finder Coronagraph Observatory summary  

NASA Technical Reports Server (NTRS)

Creating an optical space telescope observatory capable of detecting and characterizing light from extra-solar terrestrial planets poses technical challenges related to extreme wavefront stability. The Terrestrial Planet Finder Coronagraph design team has been developing an observatory based on trade studies, modeling and analysis that has guided us towards design choices to enable this challenging mission. This paper will describe the current flight baseline design of the observatory and the trade studies that have been performed. The modeling and analysis of this design will be described including predicted performance and the tasks yet to be done.

Ford, Virginia; Levine-Westa, Marie; Kissila, Andy; Kwacka, Eug; Hoa, Tim; Dumonta, Phil; Lismana, Doug; Fehera, Peter; Cafferty, Terry

2005-01-01

79

Reducing Extra-Terrestrial Excavation Forces with Percussion  

NASA Technical Reports Server (NTRS)

High launch costs and mission requirements drive the need for low mass excavators with mobility platforms, which in turn have little traction and excavation reaction capacity in low gravity environments. This presents the need for precursor and long term future missions with low mass robotic mining technology to perform In-Situ Resource Utilization (ISRU) tasks. This paper discusses a series of experiments that investigate the effectiveness of a percussive digging device to reduce excavation loads and thereby the mass of the excavator itself. A percussive mechanism and 30" wide pivoting bucket were attached at the end of the arm simulating a basic backhoe with a percussion direction tangent to the direction of movement. Impact energies from 13.6J to 30.5J and frequencies from 0 BPM to 700 BPM were investigated. A reduction in excavation force of as much as 50% was achieved in this experimental investigation.

Mueller, Robert; Schuler, Jason M.; Smith, Jonathan Drew; Nick, Andrew J.; Lippitt, Thomas

2012-01-01

80

Satellite Radiotomography of Ionospheric Responces to Extra-Terrestrial Forcing  

NASA Astrophysics Data System (ADS)

Our work addresses the study of the response of the atmosphere and ionosphere to a variety of external forcing such as solar flares and particle precipitation. Particle precipitation plays important role in the system of magnetosphere-ionosphere- atmosphere coupling during geomagnetic storms. Using radio tomographic imaging of the ionosphere based on navigational satellite systems (Parus/Transit and GPS/GLONASS) we present and discuss the examples illustrating ionospheric effects caused by particle precipitations detected by DMSP satellites. It is shown that the spatial structure of corpuscular ionization in the tomographic images is qualitatively close to latitudinal distribution of the precipitating particles. The distributions of ionospheric plasma observed during strong geomagnetic disturbances and particle precipitations have multiple extrema and wave-like structures with a spatial scale ranging from a few dozens to a few hundreds of kilometers; the characteristic sizes of latitudinal variations in the corresponding corpuscular flows widely vary from a few degrees to a few dozens degrees latitude. The obtained experimental results are in good agreement with the results of the numeric modelling of the AGW generation by volumetric sources. We also present the comparison of the effects of ionization of the ionosphere by a series of intense X-class solar flares during the 23rd and 24th solar cycles based on the data of satellite navigation and augumentation systems (GPS/GLONASS and SBAS). The analysis shows that the intensity of the ionospheric effects estimated from the variations in total electron content is barely related to the intensity of the X-ray flare for the X-class events. The amplitude of variations in the ionization of the upper atmosphere is mainly controlled by the intensity of variations in solar EUV radiation, which is not always correlated to the X-Ray radiation during flares. The authors acknowledge the support of the Russian Foundation for Basic Research (grants ? 13-05-01122, 14-05-31445, 14-05-00855, 14-05-10069), grants of the President of Russian Federation (MK-2670.2014.5) and Lomonosov Moscow State University Program of Development.

Kunitsyn, Viacheslav; Padokhin, Artem; Andreeva, Elena; Tereshchenko, Evgeny; Nesterov, Ivan; Vorontsov, Artem

81

Astronomers Reveal Extinct Extra-Terrestrial Fusion Reactor  

NASA Astrophysics Data System (ADS)

An international team of astronomers, studying the left-over remnants of stars like our own Sun, have found a remarkable object where the nuclear reactor that once powered it has only just shut down. This star, the hottest known white dwarf, H1504+65, seems to have been stripped of its entire outer regions during its death throes leaving behind the core that formed its power plant. Scientists from the United Kingdom, Germany and the USA focused two of NASA's space telescopes, the Chandra X-ray Observatory and the Far Ultraviolet Spectroscopic Explorer (FUSE), onto H1504+65 to probe its composition and measure its temperature. The data revealed that the stellar surface is extremely hot, 200,000 degrees, and is virtually free of hydrogen and helium, something never before observed in any star. Instead, the surface is composed mainly of carbon and oxygen, the 'ashes' of the fusion of helium in a nuclear reactor. An important question we must answer is why has this unique star lost the hydrogen and helium, which usually hide the stellar interior from our view? Professor Martin Barstow (University of Leicester) said. 'Studying the nature of the ashes of dead stars give us important clues as to how stars like the Sun live their lives and eventually die. The nuclear waste of carbon and oxygen produced in the process are essential elements for life and are eventually recycled into interstellar space to form new stars, planets and, possibly, living beings.' Professor Klaus Werner (University of Tübingen) said. 'We realized that this star has, on astronomical time scales, only very recently shut down nuclear fusion (about a hundred years ago). We clearly see the bare, now extinct reactor that once powered a bright giant star.' Dr Jeffrey Kruk (Johns Hopkins University) said: 'Astronomers have long predicted that many stars would have carbon-oxygen cores near the end of their lives, but I never expected we would actually be able to see one. This is a wonderful opportunity to improve our understanding of the life-cycle of stars.' The Chandra X-ray data also reveal the signatures of neon, an expected by-product of helium fusion. However, a big surprise was the presence of magnesium in similar quantities. This result may provide a key to the unique composition of H1504+65 and validate theoretical predictions that, if massive enough, some stars can extend their lives by tapping yet another energy source: the fusion of carbon into magnesium. However, as magnesium can also be produced by helium fusion, proof of the theory is not yet ironclad. The final link in the puzzle would be the detection of sodium, which will require data from yet another observatory: the Hubble Space Telescope. The team has already been awarded time on the Hubble Space Telescope to search for sodium in H1504+65 next year, and will, hopefully, discover the final answer as to the origin of this unique star. This work will be published in July in the 'Astronomy & Astrophysics' journal. The Chandra X-ray Observatory and the Far Ultraviolet Spectroscopic Explorer (FUSE) were both launched into orbit by NASA in 1999. Their instruments make use of a technique called spectroscopy, which spreads the light obtained from astronomical objects into its constituent X-ray and ultraviolet 'colours', in the same way visible light is dispersed into a rainbow naturally, by water droplets in the atmosphere, or artificially, by a prism. When studied in fine detail each spectrum is a unique 'fingerprint' which tells us what elements are present and reveals the physical conditions in the object being studied. Related Internet Address http://www.ras.org.uk/index.php?option=com_content&task=view&id=673&Itemid=2

2004-06-01

82

Extra-terrestrial Life in the Milky Way Galaxy?  

NASA Astrophysics Data System (ADS)

Are we alone? Along with questions about black holes, this is one of the questions most commonly asked of astrophysicists. While the simple answer is that we don't know, logical and rational exploration of the question can be illuminating and a very good way to introduce non-scientists to the "scientific worldview." This short essay is based on a class for students not majoring in science, which I have taught for nearly forty years at the University of Texas at Austin.

Evans, Neal J.

2014-09-01

83

Extra-terrestrial nuclear power stations : transportation and operation  

E-print Network

Many challenges exist when considering nuclear power to provide electricity for bases on the Moon or Mars, including launch safety, landing safety, deployment, control, and protecting the astronauts from radiation. Examples ...

Kane, Susan Christine

2005-01-01

84

A SETI experiment. [Search for Extra Terrestrial Intelligence  

NASA Technical Reports Server (NTRS)

In order to increase the probability of contact in the search for extraterrestrial intelligence (SETI), it has been proposed to search more intensively in certain regions of the electromagnetic spectrum ('the water hole'). The present paper describes a similar narrowing of the search in the time domain. Application of this strategy results in the SETI experiments searching for signals from the Tau Ceti system late in 1986 and early in 1987, and from the Epsilon Eridani system in mid 1988.

Mclaughlin, W. I.

1986-01-01

85

Accretion and differentiation of the terrestrial planets with implications for the compositions of early-formed Solar System bodies and accretion of water  

NASA Astrophysics Data System (ADS)

In order to test accretion simulations as well as planetary differentiation scenarios, we have integrated a multistage core-mantle differentiation model with N-body accretion simulations. Impacts between embryos and planetesimals are considered to result in magma ocean formation and episodes of core formation. The core formation model combines rigorous chemical mass balance with metal-silicate element partitioning data and requires that the bulk compositions of all starting embryos and planetesimals are defined as a function of their heliocentric distances of origin. To do this, we assume that non-volatile elements are present in Solar System (CI) relative abundances in all bodies and that oxygen and H2O contents are the main compositional variables. The primary constraint on the combined model is the composition of the Earth's primitive mantle. In addition, we aim to reproduce the composition of the martian mantle and the mass fractions of the metallic cores of Earth and Mars. The model is refined by least squares minimization with up to five fitting parameters that consist of the metal-silicate equilibration pressure and 1-4 parameters that define the starting compositions of primitive bodies. This integrated model has been applied to six Grand Tack N-body accretion simulations. Investigations of a broad parameter space indicate that: (1) accretion of Earth was heterogeneous, (2) metal-silicate equilibration pressures increase as accretion progresses and are, on average, 60-70% of core-mantle boundary pressures at the time of each impact, and (3) a large fraction (70-100%) of the metal of impactor cores equilibrates with a small fraction of the silicate mantles of proto-planets during each core formation event. Results are highly sensitive to the compositional model for the primitive starting bodies and several accretion/core-formation models can thus be excluded. Acceptable fits to the Earth's mantle composition are obtained only when bodies that originated close to the Sun, at <0.9-1.2 AU, are highly reduced and those from beyond this distance are increasingly oxidized. Reasonable concentrations of H2O in Earth's mantle are obtained when bodies originating from beyond 6-7 AU contain 20 wt% water ice (icy bodies that originated between the snow line and this distance did not contribute to Earth's accretion because they were swept up by Jupiter and Saturn). In the six models examined, water is added to the Earth mainly after 60-80% of its final mass has accreted. The compositional evolution of the mantles of Venus and Mars are also constrained by the model. The FeO content of the martian mantle depends critically on the heliocentric distance at which the Mars-forming embryo originated. Finally, the Earth's core is predicted to contain 8-9 wt% silicon, 2-4 wt% oxygen and 10-60 ppm hydrogen, whereas the martian core is predicted to contain low concentrations (<1 wt%) of Si and O.

Rubie, D. C.; Jacobson, S. A.; Morbidelli, A.; O'Brien, D. P.; Young, E. D.; de Vries, J.; Nimmo, F.; Palme, H.; Frost, D. J.

2015-03-01

86

The range of validity of the two-body approximation in models of terrestrial planet accumulation. II - Gravitational cross sections and runaway accretion  

NASA Technical Reports Server (NTRS)

The validity of the two-body approximation in calculating encounters between planetesimals has been evaluated as a function of the ratio of unperturbed planetesimal velocity (with respect to a circular orbit) to mutual escape velocity when their surfaces are in contact (V/V-sub-e). Impact rates as a function of this ratio are calculated to within about 20 percent by numerical integration of the equations of motion. It is found that when the ratio is greater than 0.4 the two-body approximation is a good one. Consequences of reducing the ratio to less than 0.02 are examined. Factors leading to an optimal size for growth of planetesimals from a swarm of given eccentricity and placing a limit on the extent of runaway accretion are derived.

Wetherill, G. W.; Cox, L. P.

1985-01-01

87

Accretion and differentiation of the terrestrial planets with implications for the compositions of early-formed Solar System bodies and accretion of water  

E-print Network

In order to test planetary accretion and differentiation scenarios, we integrated a multistage core-mantle differentiation model with N-body accretion simulations. Impacts between embryos and planetesimals result in magma ocean formation and episodes of core formation. The core formation model combines rigorous chemical mass balance with metal-silicate element partitioning data. The primary constraint on the combined model is the composition of the Earth's primitive mantle, the composition of the Martian mantle, and the mass fractions of the metallic cores of Earth and Mars. The model is refined by least squares minimization with up to five fitting parameters that consist of the metal-silicate equilibrium pressure and 1-4 parameters that define the starting compositions of primitive bodies. This integrated model has been applied to 6 Grand Tack simulations. Investigations of a broad parameter space indicate that: accretion of Earth was heterogeneous, metal-silicate equilibration pressures increase as accretio...

Rubie, David C; Morbidelli, Alessandro; O'Brien, Dave P; Young, Ed D; de Vries, Jellie; Palme, Herbert; Frost, Daniel J

2014-01-01

88

Earth and the Terrestrial  

E-print Network

Earth and the Geology of the Terrestrial Planets (Bennett et al. Ch. 9) #12; Terrestrial planets Major Ideas In This Chapter #12;Terrestrial Planets (NASA) Compared to Jovian planets: ­ Smaller size or no moons ­ No rings #12;Planetary Surfaces and Interiors Terrestrial planets + Moon were similar when

Walter, Frederick M.

89

extra-curricular community..?  

E-print Network

Do your extra-curricular activities help our community..? 2012-2013 Bloom Family ScholarshipBloom Family ScholarshipBloom Family ScholarshipBloom Family Scholarship Established in 1996 by alumni Steven H://involvement.binghamton.edu and log in. Go to the "My Involvement" tab at the top of the page, then under "My Organization Memberships

Suzuki, Masatsugu

90

Physics From Extra Dimensions  

E-print Network

A brief review of the recent developments in the physics from extra dimensions is given with a focus on the effects of Kaluza-Klein excitations in the Standard Model sector. It is shown that the current accurate data on the Fermi constant and on other electro-weak parameters puts a lower bound on the scale of extra dimensions of $\\sim$ 3 TeV, and thus the observation of such dimensions lies beyond the reach of accelerators in the near future. The correction to the anomalous magnetic moment of the muon from extra dimensions is discussed and one finds that with the current limit on the scale of extra dimensions from the Fermi constant, the correction to $g_{\\mu}-2$ does not compete with the potentially large contributions from the supersymmetric electro-weak correction. The possibility of generating Kaluza-Klein excitations associated with large radius compactifications at the LHC is discussed. It is shown that if such excitations are indeed produced their resonance structure will encode information on the number of compactified dimensions as well as on the nature of the specific orbifold compactification. A brief discussion of difficulties such as rapid proton decay that one encounters in theories with large radius compactifications is given.

Pran Nath

2000-12-06

91

The Search for other Earths: limits on the giant planet orbits that allow habitable terrestrial planets to form  

E-print Network

Gas giant planets are far easier than terrestrial planets to detect around other stars, and are thought to form much more quickly than terrestrial planets. Thus, in systems with giant planets, the late stages of terrestrial planet formation are strongly affected by the giant planets' dynamical presence. Observations of giant planet orbits may therefore constrain the systems that can harbor potentially habitable, Earth-like planets. We present results of 460 N-body simulations of terrestrial accretion from a disk of Moon- to Mars-sized planetary embryos. We systematically vary the orbital semimajor axis of a Jupiter-mass giant planet between 1.6 and 6 AU, and eccentricity between 0 and 0.4. We find that for Sun-like stars, giant planets inside roughly 2.5 AU inhibit the growth of 0.3 Earth-mass planets in the habitable zone. If planets accrete water from volatile-rich embryos past 2-2.5 AU, then water-rich habitable planets can only form in systems with giant planets beyond 3.5 AU. Giant planets with significant orbital eccentricities inhibit both accretion and water delivery. The majority of the current sample of extra-solar giant planets appears unlikely to form habitable planets.

Sean N. Raymond

2006-05-04

92

Extra Credit Crossword Puzzles  

NSDL National Science Digital Library

These are two crossword puzzles that I hand out for extra credit, one for the igneous half of the course and the other for the metamorphic half. The puzzles reinforce concepts, vocabulary, and mineral formulae that we have gone over in class and labs. The students *love* them, and usually end up working on them in groups. Both puzzles were created using the Discovery Channel Puzzlemaker: http://puzzlemaker.school.discovery.com.

Jane Selverstone

93

Extra Credit Problem Set  

NSDL National Science Digital Library

This problem set was assigned at the end of the year as a way for the students to get some extra credit and to help them study for the final exam. The problem set has 3 parts: 1) Strain: finding S1 and S3, measuring angular shear, and determining coaxial vs. noncoaxial deformation, 2) Calculating surface stresses on an inclined surface, and 3) Mohr stress circles.

Sarah Brownlee

94

Extra Housepayments Effect  

NSDL National Science Digital Library

How financial institutions use the monthly mortgage payment and mortgage amortization formulas can be a confusing concept to grasp. This lesson asks students to find a current interest mortgage rate for their city and state. This rate is then applied to an Internet based mortgage calculator to discover the effect that paying extra on a monthly house payment has on total interest paid and length of the loan. A student worksheet is included in the document.

2011-01-05

95

Graviton production from extra dimensions  

E-print Network

Graviton production due to collapsing extra dimensions is studied. The momenta lying in the extra dimensions are taken into account. A $D$-dimensional background is matched to an effectively four-dimensional standard radiation dominated universe. Using observational constraints on the present gravitational wave spectrum, a bound on the maximal temperature at the beginning of the radiation era is derived. This expression depends on the number of extra dimensions, as well as on the $D$-dimensional Planck mass. Furthermore, it is found that the extra dimensions have to be large.

Kerstin E. Kunze; Mairi Sakellariadou

2002-06-21

96

Phenomenology of Extra Dimensions  

SciTech Connect

If the structure of spacetime is different than that readily observed, gravitational physics, particle physics and cosmology are all immediately affected. The physics of extra dimensions offers new insights and solutions to fundamental questions arising in these fields. Novel ideas and frameworks are continuously born and evolved. They make use of string theoretical features and tools and they may reveal if and how the 11-dimensional string theory is relevant to our four-dimensional world. We have outlined some of the experimental observations in particle and gravitational physics as well as astrophysical and cosmological considerations that can constrain or confirm these scenarios. These developing ideas and the wide interdisciplinary experimental program that is charted out to investigate them mark a renewed effort to describe the dynamics behind spacetime. We look forward to the discovery of a higher dimensional spacetime.

Hewett, J.L.; /SLAC

2006-11-07

97

Impact erosion of terrestrial planetary atmospheres  

NASA Technical Reports Server (NTRS)

I review current ideas about the nature of the planetesimals - composition, size distribution, and the planetary encounter velocity. Previous papers on accretion and erosion of planetary atmospheres as a result of multiple impacts are reviewed. Finally, the effects of blowing off a substantial fraction of the atmosphere from a terrestrial planet due to a single giant body impact are discussed.

Ahrens, Thomas J.

1992-01-01

98

Cosmology with extra dimensions  

NASA Astrophysics Data System (ADS)

We review several properties of models that include extra dimensions, focusing on aspects related to cosmology and particle physics phenomenology. The properties of effective four dimensional inflationary geometry are studied in two distinct frameworks: (i) in Kaluza-Klein (KK) compactifications and (ii) in braneworld scenarios. From numerical simulations we find that inflationary braneworlds are unstable if the scale of inflation is too large in comparison with the stabilization scale of the interbrane distance. The analysis of perturbations confirms the existence of a tachyon associated with the volume modulus of the extra dimensions both in braneworlds and KK compactifications. With the numerical program BRANECODE non-perturbative properties of braneworlds are studied. We fully understand the non-perturbative consequences of this instability. Generic attractors are (i) an increase of the interbrane distance and the formation of a naked singularity, (ii) the brane collision, and (iii) the non-linear reconfiguration of the braneworld towards a stable configuration connected with a lower scale of inflation. The most interesting features are understood analytically. In the limit of flat branes, we exactly identify the radion of a two-brane/bulk scalar field system and explore its interactions with the standard model fields located on the branes as one phenomenological consequence. This complex calculation consists of the diagonalization of the five-dimensional Einstein-Hilbert action to second order in the perturbations. Enhanced complexity in comparison to similar calculations performed for the inflaton field in four-dimensional cosmology arises due to the presence of non-trivial boundary conditions. Open questions in cosmology, such as the nature of dark energy and the low power in the quadrupole of the temperature anisotropies of the cosmic microwave background (CMB) radiation, motivate investigations beyond the standard model of cosmology. The simplest generalization of the cosmological constant is provided by a scalar field. We explore the possible dynamics of such scalar fields in the universe at late times. In particular, we focus on their impact on the temperature anisotropies of the CMB. We show that dynamical dark energy does not yield a suppression of power on the largest scales of the CMB for a wide range of potentials.

Martin, Johannes

99

Practicality of Using Oxygen Atom Emissions to Evaluate the Habitability of ExtraSolar Planets  

Microsoft Academic Search

It has previously been proposed [Akasofu, 1999] that observation of the O(1S - 1D) green line from the atmospheres of extra-solar planets might be a marker for habitability. Guidance on this question is available within our own solar system. The green line is a dominant feature in the visible terrestrial nightglow, and the ultimate origin of its mesospheric emission is

T. G. Slanger

2005-01-01

100

Mars the recording angel: Traces of extra-Martian events in polar layered terrain  

Microsoft Academic Search

The layered terrain of the Martian poles must capture evidence of past events and processes extrinsic to the Martian environment itself. These include: solar radiation and cosmic rays; impacts by comets and asteroids; meteorites from the terrestrial planets; and perhaps even traces of visits by extra-Martian intelligences. The purpose of this paper is to outline the mechanisms behind such traces,

S. Baxter

2005-01-01

101

Terrestrial Analogs to Mars  

Microsoft Academic Search

It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing. These studies include field workshops, characterization of terrestrial analog sites, instrument tests,

T. G. Farr; S. Arcone; R. W. Arvidson; V. Baker; N. G. Barlow; D. Beaty; M. S. Bell; D. D. Blankenship; N. Bridges; G. Briggs; M. Bulmer; F. Carsey; S. M. Clifford; R. A. Craddock; P. W. Dickerson; N. Duxbury; G. L. Galford; J. Garvin; J. Grant; J. R. Green; T. K. P. Gregg; E. Guinness; V. L. Hansen; M. H. Hecht; J. Holt; A. Howard; L. P. Keszthelyi; P. Lee; P. D. Lanagan; R. C. F. Lentz; D. W. Leverington; L. Marinangeli; J. E. Moersch; P. A. Morris-Smith; P. Mouginis-Mark; G. R. Olhoeft; G. G. Ori; P. Paillou; J. F. Reilly II; J. W. Rice Jr.; C. A. Robinson; M. Sheridan; K. Snook; B. J. Thomson; K. Watson; K. Williams; K. Yoshikawa

2002-01-01

102

Terrestrial Planets: Comparative Planetology  

NASA Technical Reports Server (NTRS)

Papers were presented at the 47th Annual Meteoritical Society Meeting on the Comparative planetology of Terrestrial Planets. Subject matter explored concerning terrestrial planets includes: interrelationships among planets; plaentary evolution; planetary structure; planetary composition; planetary Atmospheres; noble gases in meteorites; and planetary magnetic fields.

1985-01-01

103

TERRESTRIAL ECOSYSTEM SIMULATOR  

EPA Science Inventory

The Terrestrial Habitats Project at the Western Ecology Division (Corvallis, OR) is developing tools and databases to meet the needs of Program Office clients for assessing risks to wildlife and terrestrial ecosystems. Because habitat is a dynamic condition in real-world environm...

104

To What Extent Does Terrestrial Life ``Follow The Water''? Eriita G. Jones and Charles H. Lineweaver  

E-print Network

Table 1 for the surface P-T conditions of Solar System bodies. Figure 1 is a sketch of our main goalTo What Extent Does Terrestrial Life ``Follow The Water''? Eriita G. Jones and Charles H. Lineweaver Abstract Terrestrial life is known to require liquid water, but not all terrestrial water

Lineweaver, Charles H.

105

Neutrino and Extra World  

E-print Network

The neutrino speed measurement experiments are the continuations of the classic light speed measurement experiments have been done in range of the solar planet system (Ole Roemer, 1676), in star system (James Braidely, 1728) and, at last, on the Earth (Lois Fizeau, 1849),.... The finite light speed measurement has led to the revolution in the humanity consciousness and eventually led to a new understanding of the visible universe. In 1998-2005, we had a lot of excited discussions at CERN about the possibilities to perform the neutrino experiments to test the superluminal neutrino hypothesis and to find new phenomena beyond the SM. From one hand the idea of such experiments was associated with the hope to understand the role of the V-A- weak interactions, the quark-lepton family symmetry, the neutrino space-time properties and to observe some indications on a new vacuum structure existence outside of the Weak Scale, i.e. in the region 1/R ~ (0.1-20) TeV. From another hand the general trends of this idea has been related to the possible existence some extra space-time noncompact dimensions of the universe. In this context it would be first serious encounter with the dual conception between the physical phenomena of microcosmos and of universe. One of the main goals is to find some new space-time peculiarities and structures that might explain the formation of our visible D=(3+1)-universe with all its space-time and internal symmetries which could be only a part of a vast Universe filled with other kinds of matter. The main difficulties of such experiments related to the possible relativity principle paradoxes have been discussed.

D. S. Baranov; G. G. Volkov

2012-11-20

106

Mars: destructive and constructive processes in its crust reflecting tendencies of leveling angular momenta of tropics and extra-tropics  

Microsoft Academic Search

Mars: destructive and constructive processes in its crust reflecting tendencies of leveling angular momenta of tropics and extra-tropics. G. Kochemasov IGEM of the Russian Academy of Sciences A globular shape of rotating celestial bodies means that their tropical and extra-tropical belts have significantly different angular momenta. But such unevenness in a single body is disturbing because it increases level of

G. G. Kochemasov

2009-01-01

107

Terrestrial Impact Structures  

NASA Astrophysics Data System (ADS)

Emphasis is placed on the nature of terrestrial impact structures, the criteria for their identification, and their contribution to constraining formational processes and cratering rate estimates. The relationship of large-scale impact to Earth history is also considered.

Grieve, R. A. F.

108

Terrestrial photovoltaic measurements, 2  

NASA Technical Reports Server (NTRS)

The following major topics are discussed; (1) Terrestrial solar irradiance; (2) Solar simulation and reference cell calibration; and (3) Cell and array measurement procedures. Numerous related subtopics are also discussed within each major topic area.

1976-01-01

109

Primordial Terrestrial Xenon Revisited  

NASA Astrophysics Data System (ADS)

Xenon solar wind composition revealed by Genesis matches mathematically derived primordial terrestrial xenon with high precision, except for 136Xe and 134Xe. This can be explained by modification of fission yields in open systems.

Meshik, A. P.; Pravdivtseva, O. V.; Hohenberg, C. M.

2014-09-01

110

Terrestrial Planet Finder  

NASA Technical Reports Server (NTRS)

Integrating and testing the proposed Terrestrial Planet Finder imposes constraints on the design. Some of these will be discussed including the dimensions of existing test facilities, the effects of gravity, ambient vibrations and the size of GSE optics.

Smith, Andrew

2004-01-01

111

Terrestrial and Extraterrestrial Fullerenes  

Microsoft Academic Search

This paper reviews reports of occurrences of fullerenes in circumstellar media, interstellar media, meteorites, interplanetary dust particles (IDPs), lunar rocks, hard terrestrial rocks from Shunga (Russia), Sudbury (Canada) and Mitov (Czech Republic), coal, terrestrial sediments from the Cretaceous?Tertiary?Boundary and Permian?Triassic?Boundary, fulgurite, ink sticks, dinosaur eggs, and a tree char. The occurrences are discussed in the context of known and postulated

D. Heymann; L. W. Jenneskens; J. Jehli?ka; Carola Koper; E. J. Vlietstra

2003-01-01

112

Comparative Climatology of Terrestrial Planets  

NASA Astrophysics Data System (ADS)

Public awareness of climate change on Earth is currently very high, promoting significant interest in atmospheric processes. We are fortunate to live in an era where it is possible to study the climates of many planets, including our own, using spacecraft and groundbased observations as well as advanced computational power that allows detailed modeling. Planetary atmospheric dynamics and structure are all governed by the same basic physics. Thus differences in the input variables (such as composition, internal structure, and solar radiation) among the known planets provide a broad suite of natural laboratory settings for gaining new understanding of these physical processes and their outcomes. Diverse planetary settings provide insightful comparisons to atmospheric processes and feedbacks on Earth, allowing a greater understanding of the driving forces and external influences on our own planetary climate. They also inform us in our search for habitable environments on planets orbiting distant stars, a topic that was a focus of Exoplanets, the preceding book in the University of Arizona Press Space Sciences Series. Quite naturally, and perhaps inevitably, our fascination with climate is largely driven toward investigating the interplay between the early development of life and the presence of a suitable planetary climate. Our understanding of how habitable planets come to be begins with the worlds closest to home. Venus, Earth, and Mars differ only modestly in their mass and distance from the Sun, yet their current climates could scarcely be more divergent. Our purpose for this book is to set forth the foundations for this emerging science and to bring to the forefront our current understanding of atmospheric formation and climate evolution. Although there is significant comparison to be made to atmospheric processes on nonterrestrial planets in our solar system — the gas and ice giants — here we focus on the terrestrial planets, leaving even broader comparisons to a future volume. Our authors have taken on the task to look at climate on the terrestrial planets in the broadest sense possible — by comparing the atmospheric processes at work on the four terrestrial bodies, Earth, Venus, Mars, and Titan (Titan is included because it hosts many of the common processes), and on terrestrial planets around other stars. These processes include the interactions of shortwave and thermal radiation with the atmosphere, condensation and vaporization of volatiles, atmospheric dynamics, chemistry and aerosol formation, and the role of the surface and interior in the long-term evolution of climate. Chapters herein compare the scientific questions, analysis methods, numerical models, and spacecraft remote sensing experiments of Earth and the other terrestrial planets, emphasizing the underlying commonality of physical processes. We look to the future by identifying objectives for ongoing research and new missions. Through these pages we challenge practicing planetary scientists, and most importantly new students of any age, to find pathways and synergies for advancing the field. In Part I, Foundations, we introduce the fundamental physics of climate on terrestrial planets. Starting with the best studied planet by far, Earth, the first chapters discuss what is known and what is not known about the atmospheres and climates of the terrestrial planets of the solar system and beyond. In Part II, Greenhouse Effect and Atmospheric Dynamics, we focus on the processes that govern atmospheric motion and the role that general circulation models play in our current understanding. In Part III, Clouds and Hazes, we provide an in-depth look at the many effects of clouds and aerosols on planetary climate. Although this is a vigorous area of research in the Earth sciences, and very strongly influences climate modeling, the important role that aerosols and clouds play in the climate of all planets is not yet well constrained. This section is intended to stimulate further research on this critical subject. The study of climate involves much more than

Mackwell, Stephen J.; Simon-Miller, Amy A.; Harder, Jerald W.; Bullock, Mark A.

113

[Extra-articular elbow arthroscopy].  

PubMed

Extra-articular elbow arthroscopy has to be considered as the evolution of the elbow surgery to a mini invasive endoscopically assisted surgery developed by the recent advance of the elbow arthroscopy. Various pathologies, such as lateral epicondylitis, ulnar nerve entrapment, distal Biceps tendon rupture, synovial cysts, or olecranon bursitis have been treated arthroscopically. Extra-articular pathologies can be treated through an intra-articular endoscopic approach. The true endoscopic extra-articular technique is proced through a real anatomical space or inside a space of work created de novo by the surgeon. The difficulty of using endoscopy in extra-articular pathologies of the elbow is related to the vasculo-nervous structures sourrounding the articulation wich are directly subject to potential injury. Elbow extra-articular endoscopy must be considered as a difficult and sometimes dangerous procedure reserved to experimented elbow arthroscopic surgeons. Those techniques are yet to demonstrate their superiority in term of results and security compare to the open techniques. PMID:17361882

Lenoble, E

2006-11-01

114

Mon. Not. R. Astron. Soc. (2010) doi:10.1111/j.1365-2966.2010.17027.x The interplay of chaos between the terrestrial and giant planets  

E-print Network

between the terrestrial and giant planets Wayne B. Hayes,1,2 Anton V. Malykh1 and Christopher M. Danforth3 the four inner terrestrial planets and several post-Newtonian corrections such as general relativity at the isolated five-body system of the Sun + four terrestrial planets, then the terrestrial planets alone show

Danforth, Chris

2010-01-01

115

Collider searches for extra dimensions  

SciTech Connect

Searches for extra spatial dimensions remain among the most popular new directions in our quest for physics beyond the Standard Model. High-energy collider experiments of the current decade should be able to find an ultimate answer to the question of their existence in a variety of models. Until the start of the LHC in a few years, the Tevatron will remain the key player in this quest. In this paper, we review the most recent results from the Tevatron on searches for large, TeV{sup -1}-size, and Randall-Sundrum extra spatial dimensions, which have reached a new level of sensitivity and currently probe the parameter space beyond the existing constraints. While no evidence for the existence of extra dimensions has been found so far, an exciting discovery might be just steps away.

Landsberg, Greg; /Brown U.

2004-12-01

116

The debris disk - terrestrial planet connection  

NASA Astrophysics Data System (ADS)

The eccentric orbits of the known extrasolar giant planets provide evidence that most planet-forming environments undergo violent dynamical instabilities. Here, we numerically simulate the impact of giant planet instabilities on planetary systems as a whole. We find that populations of inner rocky and outer icy bodies are both shaped by the giant planet dynamics and are naturally correlated. Strong instabilities - those with very eccentric surviving giant planets - completely clear out their inner and outer regions. In contrast, systems with stable or low-mass giant planets form terrestrial planets in their inner regions and outer icy bodies produce dust that is observable as debris disks at mid-infrared wavelengths. Fifteen to twenty percent of old stars are observed to have bright debris disks (at ? ~ 70?m) and we predict that these signpost dynamically calm environments that should contain terrestrial planets.

Raymond, Sean N.; Armitage, Philip J.; Moro-Martín, Amaya; Booth, Mark; Wyatt, Mark C.; Armstrong, John C.; Mandell, Avi M.; Selsis, Franck

2011-11-01

117

Terrestrial atmosphere, water and astrobiology  

NASA Astrophysics Data System (ADS)

Primitive life, defined as a chemical system capable to transfer its molecular information via self-replication and also capable to evolve, originated about 4 billion years ago from the processing of organic molecules by liquid water. Terrestrial atmosphere played a key role in the process by allowing the permanent presence of liquid water and by participating in the production of carbon-based molecules. Water molecules exhibit specific properties mainly due to a dense network of hydrogen bonds. The carbon-based molecules were either home made in the atmosphere and/or in submarine hydrothermal systems or delivered by meteorites and micrometeorites. The search for possible places beyond the earth where the trilogy atmosphere/water/life could exist is the main objective of astrobiology. Within the Solar System, exploration missions are dedicated to Mars, Europa, Titan and the icy bodies. The discovery of several hundreds of extrasolar planets opens the quest to the whole Milky Way.

Brack, A.; Coradini, M.

2010-12-01

118

Contrasting coloration in terrestrial mammals  

PubMed Central

Here I survey, collate and synthesize contrasting coloration in 5000 species of terrestrial mammals focusing on black and white pelage. After briefly reviewing alternative functional hypotheses for coloration in mammals, I examine nine colour patterns and combinations on different areas of the body and for each mammalian taxon to try to identify the most likely evolutionary drivers of contrasting coloration. Aposematism and perhaps conspecific signalling are the most consistent explanations for black and white pelage in mammals; background matching may explain white pelage. Evidence for contrasting coloration is being involved in crypsis through pattern blending, disruptive coloration or serving other functions, such as signalling dominance, lures, reducing eye glare or in temperature regulation has barely moved beyond anecdotal stages of investigation. Sexual dichromatism is limited in this taxon and its basis is unclear. Astonishingly, the functional significance of pelage coloration in most large charismatic black and white mammals that were new to science 150 years ago still remains a mystery. PMID:18990666

Caro, Tim

2008-01-01

119

Experimental Tribulus terrestris poisoning in goats  

Microsoft Academic Search

Seven, 1–2-year-old native goats were fed dried Tribulus terrestris from Sabzevar district of Khorasan province for 8 weeks. Two goats showed clinical signs of toxicity including weight loss, depression, ruminal stasis, icterus and elevation of body temperature. Haematological and biochemical trails revealed a declining of packed cell volume (PCV) and plasma total protein and elevation of total and direct bilirubin,

M. R. Aslani; A. R. Movassaghi; M. Mohri; V. Ebrahim-pour; A. N. Mohebi

2004-01-01

120

The effect of type I migration on the formation of terrestrial planets in hot-Jupiter systems  

E-print Network

Context: Our previous models of a giant planet migrating through an inner protoplanet/planetesimal disk find that the giant shepherds a portion of the material it encounters into interior orbits, whilst scattering the rest into external orbits. Scattering tends to dominate, leaving behind abundant material that can accrete into terrestrial planets. Aims: We add to the possible realism of our model by simulating type I migration forces which cause an inward drift, and strong eccentricity and inclination damping of protoplanetary bodies. This extra dissipation might be expected to enhance shepherding at the expense of scattering, possibly modifying our previous conclusions. Methods: We employ an N-body code that is linked to a viscous gas disk algorithm capable of simulating: gas accretion onto the central star; gap formation in the vicinity of the giant planet; type II migration of the giant planet; type I migration of protoplanets; and the effect of gas drag on planetesimals. We use the code to re-run three scenarios from a previous work where type I migration was not included. Results: The additional dissipation introduced by type I migration enhances the inward shepherding of material but does not severely reduce scattering. We find that > 50% of the solids disk material still survives the migration in scattered exterior orbits: most of it well placed to complete terrestrial planet formation at terrestrial planets can form in the habitable zones of hot-Jupiter systems and hot-Earths and hot-Neptunes may also be present. These systems should be targets of future planet search missions.

Martyn J. Fogg; Richard P. Nelson

2007-07-18

121

Pedagogical Introduction to Extra Dimensions  

Microsoft Academic Search

Extra dimensions provide a new window on a number of problems faced by the Standard Model. The following provides an introduction to this very broad subject aimed at experimental graduate students and post-docs based on a lecture given at the 2004 SLAC Summer Institute.

Thomas G. Rizzo

2004-01-01

122

Origin of the 'Extra Entropy'  

NASA Technical Reports Server (NTRS)

I will discuss how one can determine the origin of the 'extra entropy' in groups and clusters and the feedback needed in models of galaxy formation. I will stress the use of x-ray spectroscopy and imaging and the critical value that Con-X has in this regard.

Mushotzky, R.

2008-01-01

123

Body Fluids Monitor  

NASA Technical Reports Server (NTRS)

Method and apparatus are described for determining volumes of body fluids in a subject using bioelectrical response spectroscopy. The human body is represented using an electrical circuit. Intra-cellular water is represented by a resistor in series with a capacitor; extra-cellular water is represented by a resistor in series with two parallel inductors. The parallel inductors represent the resistance due to vascular fluids. An alternating, low amperage, multifrequency signal is applied to determine a subject's impedance and resistance. From these data, statistical regression is used to determine a 1% impedance where the subject's impedance changes by no more than 1% over a 25 kHz interval. Circuit component, of the human body circuit are determined based on the 1% impedance. Equations for calculating total body water, extra-cellular water, total blood volume, and plasma volume are developed based on the circuit components.

Siconolfi, Steven F. (Inventor)

2000-01-01

124

Collider Phenomenology of Extra Dimensions  

SciTech Connect

In recent years there has been much interest in the possibility that there exist more spacetime dimensions than the usual four. Models of particle physics beyond the Standard Model that incorporate these extra dimensions can solve the gauge hierarchy problem and explain why the fermion masses a spread over many orders of magnitude. In this thesis we explore several possibilities for models with extra dimensions. First we examine constraints on the proposal of Arkani-Hamed and Schmaltz that the Standard Model fermions are localized to different positions in an extra dimension, thereby generating the hierarchy in fermion masses. We find strong constraints on the compactification scale of such models arising from flavor-changing neutral currents. Next we investigate the phenomenology of the Randall-Sundrum model, where the hierarchy between the electroweak and Planck scales is generated by the warping in a five-dimensional anti-de Sitter space. In particular, we investigate the ''Higgsless'' model of electroweak symmetry breaking due to Csaki et. al., where the Higgs has been decoupled from the spectrum by taking its vacuum expectation value to infinity. We find that this model produces many distinctive features at the LHC. However, we also find that it is strongly constrained by precision electroweak observables and the requirement that gauge-boson scattering be perturbative. We then examine the model with a finite vacuum expectation value, and find that there are observable shifts to the Higgs scalar properties. Finally, in the original large extra dimension scenario of Arkani-Hamed, Dimopoulos, and Dvali, the hierarchy problem is solved by allowing gravity to propagate in a large extra dimensional volume, while the Standard Model fields are confined to 4 dimensions. We consider the case where there are a large number of extra dimensions (n {approx} 20). This model can solve the hierarchy problem without introducing a exponentially large radii for the extra dimensions, and represents a scenario that is difficult to obtain in string theory. We show that, if this scenario holds, the number of dimensions can be constrained to be larger than the number predicted by critical string theory. Searching for signals of many dimensions is then an important test of whether string theory is a good description of quantum gravity.

Lillie, Benjamin Huntington; /Stanford U., Phys. Dept. /SLAC

2006-03-10

125

GLOBAL TERRESTRIAL CARBON CYCLE  

EPA Science Inventory

There is great uncertainty with regard to the future role of the terrestrial biosphere in the global carbon cycle, arising from both an inadequate understanding of current pools and fluxes as well as the potential effects of rising atmospheric concentrations of CO, on natural eco...

126

[Bites by terrestrial vertebrates].  

PubMed

Bites by terrestrial vertebrates, reptiles or mammals, represent a special risk in tropical regions. Envenomation is possible by a few lizards and many snakes. For mammals, tissular destructions due to the bite can be severe. Whatever is the offending animal, bites can further become infected by transmitted viruses or bacteria. PMID:10992781

Henry, F; Martalo, O; Claessens, N; Piérard, G E

2000-06-01

127

Terrestrial planet formation  

PubMed Central

Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (?106 y), followed by planetesimals to embryos (lunar to Mars-sized objects; few × 106 y), and finally embryos to planets (107–108 y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

Righter, K.; O’Brien, D. P.

2011-01-01

128

Terrestrials Dwarf Planets  

E-print Network

Terrestrials Gas Giants Ice Giants Dwarf Planets The Solar System #12;Neptune Uranus Saturn Jupiter Density: 3900 ­ 5500 kg m-3 #12;Jupiter 318 ME 5.2 AU Uranus 15 ME 19.6 AUSaturn 95 ME 9.5 AU Neptune 17 3.88 RE Uranus Neptune Uranus and Neptune are Ice Giants made mostly of ices with thin Hydrogen

Gaudi, B. Scott

129

Terrestrial cosmic rays  

Microsoft Academic Search

This paper reviews the basic physics of those cosmic rays which can affect terrestrial electronics. Cosmic rays at sea level consist mostly of neutrons, protons, pions, muons, electrons, and photons. The particles which cause significant soft fails in electronics are those particles with the strong interaction: neutrons, protons, and pions. At sea level, about 95% of these particles are neutrons.

James F. Ziegler

1996-01-01

130

Terrestrial photovoltaic measurement procedures  

NASA Technical Reports Server (NTRS)

Procedures for obtaining cell and array current-voltage measurements both outdoors in natural sunlight and indoors in simulated sunlight are presented. A description of the necessary apparatus and equipment is given for the calibration and use of reference solar cells. Some comments relating to concentration cell measurements, and a revised terrestrial solar spectrum for use in theoretical calculations, are included.

1977-01-01

131

The Terrestrial Planet Finder  

Microsoft Academic Search

The Terrestrial Planet Finder (TPF) is a space-based astronomical telescope that will combine high sensitivity and spatial resolution to detect and characterize ~150 planetary systems within 15 pc of our Sun. In a five-year mission, currently expected to commence in 2012, TPF will look for the atmospheric signatures of life using the methods of planetary spectroscopy. This is only possible

Peter R. Lawson

2001-01-01

132

J. Field Ornithol. 84(1):112, 2013 DOI: 10.1111/jofo.12000 Microhabitat associations of terrestrial insectivorous  

E-print Network

of terrestrial insectivorous birds in Amazonian rainforest and second-growth forests Jeffrey A. Stratford1. Across the Neotropics, small-bodied terrestrial insectivores are sensitive to forest fragmentation characterized habitat at sites where nine species of terrestrial insectivores were observed foraging, as well

Stouffer, Phil

133

Search for Extra Dimensions at CDF  

SciTech Connect

This poster, presented at the 2006 Duke Hadron Collider Symposium, presents the results from searches for large extra dimensions, as proposed by Arkani-Hamed, Dimopoulos and Dvali (ADD), and Randall-Sundrum (RS) model warped extra dimensions, at CDF.

Wynne, Sara-Madge; /Liverpool U.

2007-08-01

134

Cosmology in theories with extra dimensions  

SciTech Connect

Some possible cosmological effects of the existence of extra compact dimensions are discussed. Particular attention is given to the possibility that extra dimensions might naturally lead to an inflationary Universe scenario.

Kolb, E.W.

1985-01-01

135

Radiologic manifestations of extra-cardiac complications of infective endocarditis  

Microsoft Academic Search

Infective endocarditis (IE) is a disease with high morbidity and a mortality rate of 9–30%, even with appropriate diagnosis\\u000a and therapy. Septic emboli, caused by IE, can affect any organ or tissue in the body with an arterial supply and occur in\\u000a 12–40% of IE cases. The most common extra-cardiac organ system involved in IE is the central nervous system.

Teran W. Colen; Martin Gunn; Erin Cook; Theodore Dubinsky

2008-01-01

136

Volcanic ash - Terrestrial versus extraterrestrial  

NASA Technical Reports Server (NTRS)

A principal difference between terrestrial and extraterrestrial lavas may consist in the greater ability of terrestrial lavas to form thin films (like those of soap bubbles) and hence foams. It would follow that, in place of the pumice and spiny shards found in terrestrial volcanic ash, an extraterrestrial ash should contain minute spherules. This hypothesis may help to explain lunar microspherules.

Okeefe, J. A.

1976-01-01

137

Arsenic Speciation of Terrestrial Invertebrates  

Microsoft Academic Search

The distribution and chemical form (speciation) of arsenic in terrestrial food chains determines both the amount of arsenic available to higher organisms, and the toxicity of this metalloid in affected ecosystems. Invertebrates are part of complex terrestrial food webs. This paper provides arsenic concentrations and arsenic speciation profiles for eight orders of terrestrial invertebrates collected at three historical gold mine

Maeve M. Moriarty; Iris Koch; Robert A. Gordon; Kenneth J. Reimer

2009-01-01

138

Perirenal extra-adrenal myelolipoma  

PubMed Central

Myelolipomas are rare tumors consisting of both adipose and hematopoietic tissue and are typically found within the adrenal gland. Extra-adrenal involvement is rare, especially those tumors involving the perirenal space and collecting system. We report a case of a patient with an incidentally discovered perirenal mass that was initially concerning for a retroperitoneal liposarcoma. Following surgical resection and pathological analysis, the lesion was found to be an extra-adrenal myelolipoma. This case report and review of the literature demonstrates the importance of the proper work-up and management of perirenal lipoma variants while addressing the issues of tissue biopsy, surgical intervention, and pre- and post-operative surveillance. PMID:25032203

Hajiran, Ali; Morley, Chad; Jansen, Robert; Kandzari, Stanley; Bacaj, Patrick; Zaslau, Stanley; Cardinal, Jon

2014-01-01

139

The Physics of Extra Dimensions  

NASA Astrophysics Data System (ADS)

Lowering the string scale in the TeV region provides a theoretical framework for solving the mass hierarchy problem and unifying all interactions. The apparent weakness of gravity can then be accounted by the existence of large internal dimensions, in the submillimeter region, and transverse to a braneworld where our universe must be con?ned. I review the main properties of this scenario and its implications for observations at both particle colliders, and in non-accelerator gravity experiments. Such e?ects are for instance the production of Kaluza-Klein resonances, graviton emission in the bulk of extra dimensions, and a radical change of gravitational forces in the submillimeter range. I also discuss the warped case and localization of gravity in the presence of in?nite size extra dimensions.

Antoniadis, Ignatios

140

Extra-articular hip endoscopy  

PubMed Central

The aim of this review is to evaluate the current available literature evidencing on peri-articular hip endoscopy (the third compartment). A comprehensive approach has been set on reports dealing with endoscopic surgery for recalcitrant trochanteric bursitis, snapping hip (or coxa-saltans; external and internal), gluteus medius and minimus tears and endoscopy (or arthroscopy) after total hip arthroplasty. This information can be used to trigger further research, innovation and education in extra-articular hip endoscopy. PMID:23610664

Verhelst, L.; Guevara, V.; De Schepper, J.; Van Melkebeek, J.; Pattyn, C.; Audenaert, E. A.

2012-01-01

141

Warping the universal extra dimensions  

SciTech Connect

We develop the necessary ingredients for the construction of realistic models with warped universal extra dimensions. Our investigations are based on the seven-dimensional (7D) spacetime AdS{sub 5}xT{sup 2}/Z{sub 2} and we derive the Kaluza-Klein (KK) spectra for gravitons, bulk vectors, and the TeV brane localized Higgs boson. We show that, starting with a massive 7D fermion, one may obtain a single chiral massless mode whose profile is readily localized towards the Planck or TeV brane. This allows one to place the standard model fermions in the bulk and construct models of flavor as in Randall-Sundrum models. Our solution also admits the familiar KK parity of models with universal extra dimensions so that the lightest odd KK state is stable and may be a dark matter candidate. As an additional feature the AdS{sub 5} warping ensures that the excited modes on the torus, including the dark matter candidate, appear at TeV energies (as is usually assumed in models with universal extra dimensions) even though the Planck scale sets the dimensions for the torus.

McDonald, Kristian L. [Theory Group, TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T2A3 (Canada)

2009-07-15

142

Extra-articular Snapping Hip  

PubMed Central

Context: Snapping hip, or coxa saltans, is a vague term used to describe palpable or auditory snapping with hip movements. As increasing attention is paid to intra-articular hip pathologies such as acetabular labral tears, it is important to be able to identify and understand the extra-articular causes of snapping hip. Evidence Acquisition: The search terms snapping hip and coxa sultans were used in PubMed to locate suitable studies of any publication date (ending date, November 2008). Results: Extra-articular snapping may be caused laterally by the iliotibial band or anteriorly by the iliopsoas tendon. Snapping of the iliopsoas tendon usually requires contraction of the hip flexors and may be difficult to differentiate from intra-articular causes of snapping. Dynamic ultrasound can help detect abrupt tendon translation during movement, noninvasively supporting the diagnosis of extra-articular snapping hip. The majority of cases of snapping hip resolve with conservative treatment, which includes avoidance of aggravating activities, stretching, and anti-inflammatory medication. In recalcitrant cases, surgery to lengthen the iliotibial band or the iliopsoas tendon has produced symptom relief but may result in prolonged weakness. Conclusions: In treating active patients with snapping soft tissues around the hip, clinicians should recognize that the majority of cases resolve without surgical intervention, while being mindful of the potential for concomitant intra-articular and internal snapping hips. PMID:23015936

2010-01-01

143

Obliquity evolution of extrasolar terrestrial planets  

E-print Network

We have investigated the obliquity evolution of terrestrial planets in habitable zones (at ~ 1AU) in extrasolar planetary systems, due to tidal interactions with their satellite and host star with wide varieties of satellite-to-planet mass ratio and initial obliquity, through numerical calculations and analytical arguments. The obliquity, the angle between planetary spin axis and its orbit normal, of a terrestrial planet is one of the key factors in determining the planetary surface environments. A recent scenario of terrestrial planet accretion implies that giant impacts of Mars-sized bodies determine the planetary spin and form satellites. With isotropic giant impacts, tilted spins are more likely to be produced than straight ones and satellites with various mass are formed. However, most of previous studies have focused on a particular case of the Earth-Moon systems or the two-body planar problem. We numerically integrated the evolution of planetary spin and a satellite orbit with various satellite mass and initial obliquity. We found that in the case of initially tiled spins, the satellite's orbit migrates outward until the orbit reaches the critical radius ~ 10-20 planetary radii, but then the migration is reversed to inward one with large-amplitude oscillation. The satellite eventually falls onto the planetary surface or it is captured at the synchronous state at several planetary radii. With the results of numerical integration and analytical arguments, we identified the parameter regions of qualitatively different evolution.

Keiko Atobe; Shigeru Ida

2006-11-21

144

The Terrestrial Planet Finder and Darwin Missions  

NASA Technical Reports Server (NTRS)

Both in the United States and in Europe, teams of scientists and engineers are exploring the feasibility of the Terrestrial Planet Finder (TPF) and Darwin missions, which are designed to search for Earth-like planets in the habitable zone of nearby stars. In the US, the TPF Science Working Group is studying four options - small (4m by 6 m primary mirror) and large (4m by 10 m primary mirror) coronagraphs for planet detection at visible wavelengths, and structurally connected and free-flyer interferometers at thermal infrared wavelengths. The US TPF-SWG is charged with selecting an option for NASA by the end of 2006. In Europe the Darwin Terrestrial Exo-planet Advisory Team (TE- SAT) is exploring the free-flyer interferometer option only at this time. I will discuss the vurtures and difficulties of detecting and characterizing extra-solar planets in both wavelength regions as well as some of the technical challenges and progress in the past year.

Danchi, William C.

2004-01-01

145

NAAP ExtraSolar Planets 1/10 ExtraSolar Planets Student Guide  

E-print Network

Name: NAAP ­ ExtraSolar Planets 1/10 ExtraSolar Planets ­ Student Guide Background Material, Center of Mass, and ExtraSolar Planet Detection. Question 1: Label the positions on the star's orbit be moving. #12;NAAP ­ ExtraSolar Planets 2/10 Part I: Exoplanet Radial Velocity Simulator Introduction Open

Farritor, Shane

146

How Do I Get Rid of Extra Skin After Weight Loss?  

MedlinePLUS

... Weight Loss? KidsHealth > Teens > Q&A > Body Image & Self-Esteem > How Do I Get Rid of Extra Skin ... Parents MORE ON THIS TOPIC Body Image and Self-Esteem Stretch Marks Why Exercise Is Wise Staying at ...

147

Terrestrial Planet Formation in Binary Star Systems  

NASA Technical Reports Server (NTRS)

Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around one or both components of various young close binary star systems. If planets form at the right places within such disks, they can remain dynamically stable for very long times. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. 2002, A.J., 576, 982); giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The planetary systems formed around close binaries with stellar apastron distances less than or equal to 0.2 AU with small stellar eccentricities are very similar to those formed in the Sun-Jupiter-Saturn, whereas planetary systems formed around binaries with larger maximum separations tend to be sparser, with fewer planets, especially interior to 1 AU. Likewise, when the binary periastron exceeds 10 AU, terrestrial planets can form over essentially the entire range of orbits allowed for single stars with Jupiter-like planets, although fewer terrestrial planets tend to form within high eccentricity binary systems. As the binary periastron decreases, the radial extent of the terrestrial planet systems is reduced accordingly. When the periastron is 5 AU, the formation of Earth-like planets near 1 AU is compromised.

Lissauer, J. J.; Quintana, E. V.; Adams, F. C.; Chambers, J. E.

2006-01-01

148

Are extra-pair males different from cuckolded males? A case study and a meta-analytic examination.  

PubMed

Traditional models for female extra-pair matings assume that females benefit indirectly from extra-pair mating behaviour. Under these so-called adaptive models, extra-pair males are hypothesized to have more compatible genotypes, larger body size, exaggerated ornaments or to be older than cuckolded males. Alternatively, ('nonadaptive') models that consider female extra-pair matings to be a by-product posit that female extra-pair mating can be maintained even if there is no benefit to females. This could happen if, for example, males gained fitness benefits from extra-pair mating, while female and male extra-pair mating behaviours were genetically correlated. Extra-pair males are also expected to be older and larger if this improves their ability to convince or coerce females to mate. We investigated whether a female's extra-pair mates differed from her cuckolded mate in both genetic and phenotypic traits by analysing data from an insular house sparrow population. We found that extra-pair males were older than cuckolded males, consistent with both models. However, in contrast to the expectations from from adaptive models, extra-pair and cuckolded males were of similar genetic relatedness, and hence expected compatibility, with the female, and had comparable body size and secondary sexual traits. We also updated previous meta-analyses examining differences between extra-pair and cuckolded males. The meta-analytic results matched results from our house sparrow case study. Although we cannot completely exclude indirect benefits for females, nonadaptive models may better explain female extra-pair matings. These neglected alternative models deserve more research attention, and this should improve our understanding of the evolution of mating systems. PMID:25706253

Hsu, Yu-Hsun; Schroeder, Julia; Winney, Isabel; Burke, Terry; Nakagawa, Shinichi

2015-04-01

149

Terrestrial planet formation from a truncated disk -- The 'Grand Tack'  

NASA Astrophysics Data System (ADS)

A new terrestrial planet formation model (Walsh et al., 2011) explores the effects of a two-stage, inward-then-outward migration of Jupiter and Saturn, as found in numerous hydrodynamical simulations of giant planet formation (Masset & Snellgrove 2001, Morbidelli & Crida 2007, Pierens & Nelson 2008, Pierens & Raymond 2011). The inward migration of Jupiter truncates the disk of planetesimals and embryos in the terrestrial planet region. Subsequent accretion in that region then forms the terrestrial planets, in particular it produces the correct Earth/Mars mass ratio, which has been difficult to reproduce in simulations with a self-consistent set of initial conditions (see, eg. Raymond et al. 2009, Hansen 2009). Additionally, the outward migration of the giant planets populates the asteroid belt with distinct populations of bodies, with the inner belt filled by bodies originating inside of 3 AU, and the outer belt filled with bodies originating from beyond the giant planets. This differs from previous models of terrestrial planet formation due to the early radial mixing of material due to the giant planet's substantial migration. Specifically, the assumption that the current radial distribution of material in the inner Solar System is reflective of the primordial distribution of material in that region is no longer necessary. We will discuss the implications of this model in relation to previous models of terrestrial planet formation as well as available chemical and isotopic constraints.

Walsh, K. J.; Morbidelli, A.; Raymond, S.; O'Brien, D. P.; Mandell, A. M.

2012-12-01

150

Holography, Entropy and Extra Dimensions  

E-print Network

We show that higher dimensional models (brane worlds) in which the scale of quantum gravity $M_*$ is much smaller than the apparent scale $M_P \\sim 10^{19}$ GeV are in conflict with bounds arising from holography and black hole entropy. The thermodynamic entropy of astrophysical black holes and sub-horizon volumes during big bang nucleosynthesis exceed the relevant bounds unless $M_* > 10^{(4-6)}$ TeV, so a hierarchy relative to the weak scale is unavoidable. We discuss the implications for extra dimensions as well as holography.

Deog Ki Hong; Stephen D. H. Hsu

2004-04-30

151

Extra-solar Oort cloud encounters and planetary impact rates  

SciTech Connect

Upper limits are estimated to the number density of extra-solar Oort clouds (ESOC) through which the solar system might pass and to the probable number of attendant planetary impacts by comets. All stars are assumed to have Oort clouds. The model is based on the observed stellar spatial density and the ratio of the total number density to the observed number density. It is estimated that 486 close stellar passages and 12,160 ESOC encounters may have occurred. Each encounter would have produced a shower of hyperbolic comets, with the results of 1-3 ESOC impacts with the earth. It is concluded that the great majority of terrestrial cratering events by comets have and will come from solar Oort cloud comets. 19 references.

Stern, A.

1987-01-01

152

Antarctic terrestrial ecosystems  

SciTech Connect

The Maritime and Continental Antarctic terrestrial ecosystems are considered in the context of environmental impacts - habitat destruction, alien introductions, and pollution. Four types of pollution are considered: nutrients, radionuclides, inert materials, and noxious chemicals. Their ability to recover from perturbation is discussed in the light of present scientific knowledge, and the methods used to control impacts are reviewed. It is concluded that techniques of waste disposal are still inadequate, adequate training in environmental and conservation principles for Antarctic personnel in many countries is lacking, and scientific investigations may be a much more serious threat than tourism to the integrity of these ecosystems. Some priorities crucial to future management are suggested.

Walton, D.W.H.

1987-01-01

153

Solar terrestrial observatory  

NASA Technical Reports Server (NTRS)

Eight basic solar-terrestrial scientific objectives that benefit from the Shuttle/Platform approach and a program of measurements for each are discussed. The objectives are to understand: (1) solar variability, (2) wave-particle processes, (3) magnetosphere-ionosphere mass transport, (4) the global electric circuit, (5) upper atmospheric dynamics, (6) middle atmospheric chemistry and energetics, (7) lower atmospheric turbidity, and (8) planetary atmospheric waves. A two stage approach to a multidisciplinary payload is developed: an initial STO, that uses a single platform in a low-Earth orbit, and an advanced STO that uses two platforms in differing orbits.

1981-01-01

154

Terrestrialization, miniaturization and rates of diversification in African frogs (Anura: Phrynobatrachidae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Terrestrialization, the evolution of non-aquatic oviposition, and miniaturization, the evolution of tiny adult body size, have been identified as a key features in the evolution of modern amphibians. This study examines anuran terrestrialization and miniaturization in a phylogenetic context to deter...

155

E1.5-0032-02 SEARCHING FOR LIFE WITH THE TERRESTRIAL PLANET  

E-print Network

) on a variety of solar system bodies, including Mars, certain "hospitable" moons of the outer planets1 E1.5-0032-02 SEARCHING FOR LIFE WITH THE TERRESTRIAL PLANET FINDER: LAGRANGE POINT OPTIONS. The Terrestrial Planet Finder (TPF) is one of the key missions in NASA's Astronomical Search for Origins

Politècnica de Catalunya, Universitat

156

Bergmann's rule and the terrestrial caecilian Schistometopum thomense (Amphibia: Gymnophiona: Caeciliidae)  

Microsoft Academic Search

Question: Do caecilians follow Bergmann's rule? Hypothesis: Bergmann's rule explains the wide variation in body sizes found among populations of the terrestrial caecilian Schistometopum thomense. Field site: This is a range-wide study incorporating most terrestrial habitats throughout the island of São Tomé in the Gulf of Guinea. Methods: We performed morphological measurements on 95 museum specimens and 187 field-collected individuals

G. John Measey; Stefan Van Dongen

2006-01-01

157

Terrestrial Planet Growth in Circumbinary Disks  

NASA Technical Reports Server (NTRS)

We examine the accuulation of terrestrial from circumbinary disks surrounding pairs of stars with masses of either 0.5 solar masses each or 0.8 and 0.2 solar masses and orbital separations of 0.05 AU to 0.4 AU by performing numerical simulations of the late stages of planetary growth. Initial disks contain about 2.6 Earth masses of lunar to Mars-sized bodies orbiting within 2 AU of the center of mass of the system, plus giant planets with masses and orbits analogous to those of Jupiter and Saturn. We also performed simulations using analogous disks orbiting single 1 solar mass stars. The dynamics of planetary growth is quite chaotic because the gravitational perturbations resulting from close approaches greatly amplify differences in orbits. Thus, several simulations of each configuration were run with very slightly different initial conditions to enable us to distinguish systematic effects resulting from differences in the binary orbit (or differences of the initial orbits of the bodies within the disk) from pseudo-random variability in outcomes resulting from chaos. Most runs simulated 200 million years of evolution. At least one terrestrial planet remained at the end of each run; one simulation produced 6 terrestrial planets in a configuration that appears to be quite stable. The systems that formed around stars with binary apastron separations of less than 0.2 AU contained on average slightly more planets than those that formed around single stars, with the outermost planet typically orbiting at a greater distance from the system barycenter. Greater stellar separations tended to result in fewer planets, with the inner planet orbiting farther from the stars. More eccentric binaries have a more pronounced effect for the same apastron distance. The statistical distribution of final systems is not sensitive to moderate differences in the initial eccentricities of the bodies in the disk.

Lissauer, J. J.; Quintana, E. V.

2006-01-01

158

Earth and Terrestrial Planet Formation  

E-print Network

The growth and composition of Earth is a direct consequence of planet formation throughout the Solar System. We discuss the known history of the Solar System, the proposed stages of growth and how the early stages of planet formation may be dominated by pebble growth processes. Pebbles are small bodies whose strong interactions with the nebula gas lead to remarkable new accretion mechanisms for the formation of planetesimals and the growth of planetary embryos. Many of the popular models for the later stages of planet formation are presented. The classical models with the giant planets on fixed orbits are not consistent with the known history of the Solar System, fail to create a high Earth/Mars mass ratio, and, in many cases, are also internally inconsistent. The successful Grand Tack model creates a small Mars, a wet Earth, a realistic asteroid belt and the mass-orbit structure of the terrestrial planets. In the Grand Tack scenario, growth curves for Earth most closely match a Weibull model. The feeding zon...

Jacobson, Seth A

2015-01-01

159

Solar structure and terrestrial weather  

NASA Technical Reports Server (NTRS)

The possibility that solar activity has discernible effects on terrestrial weather is considered. Research involving correlation of weather conditions with solar and geomagnetic activity is discussed.

Wilcox, J. M.

1976-01-01

160

Terrestrial Locomotion in Penguins: It Costs More to Waddle  

Microsoft Academic Search

The energetic cost for walking is relatively higher for penguins than for other birds or for quadrupeds of similar body mass. The morphology of penguins seems to represent a compromise between aquatic and terrestrial locomotion wherein both energy economy and speed suffer when the birds move on land.

Berry Pinshow; Michael A. Fedak; Knut Schmidt-Nielsen

1977-01-01

161

Extra Chance Generalized Hybrid Monte Carlo  

NASA Astrophysics Data System (ADS)

We study a method, Extra Chance Generalized Hybrid Monte Carlo, to avoid rejections in the Hybrid Monte Carlo method and related algorithms. In the spirit of delayed rejection, whenever a rejection would occur, extra work is done to find a fresh proposal that, hopefully, may be accepted. We present experiments that clearly indicate that the additional work per sample carried out in the extra chance approach clearly pays in terms of the quality of the samples generated.

Campos, Cédric M.; Sanz-Serna, J. M.

2015-01-01

162

SOLAR PHYSICS AND TERRESTRIAL EFFECTS Solar-Terrestrial Interactions  

E-print Network

SOLAR PHYSICS AND TERRESTRIAL EFFECTS Chapter 4 Chapter 4 Solar-Terrestrial Interactions from the charged particles that reach the planet steadily as part of the solar wind and the much it will be deflected into a circular or spiral path by the Lorentz Force. Most charged particles in the solar wind

Mojzsis, Stephen J.

163

The Lunar Inclination as a Monitor of Late Stage Terrestrial Accretion  

NASA Astrophysics Data System (ADS)

We have identified a mechanism that can naturally reproduce the lunar orbital excitation and sets direct constraints on the number and mass of remnant bodies in the terrestrial planet region at the time of the Moon-forming giant impact.

Pahlevan, K.; Morbidelli, A.

2015-02-01

164

1, 167193, 2004 Terrestrial carbon  

E-print Network

BGD 1, 167­193, 2004 Terrestrial carbon budget at country-scale I. A. Janssens et al. Title Page Biogeosciences Discussions is the access reviewed discussion forum of Biogeosciences The carbon budget.janssens@ua.ac.be) 167 #12;BGD 1, 167­193, 2004 Terrestrial carbon budget at country-scale I. A. Janssens et al. Title

Paris-Sud XI, Université de

165

Terrestrial Planet Atmospheres and Biosignatures  

Microsoft Academic Search

The search for terrestrial exoplanets - rocky worlds in orbit around stars other than the Sun - is one of humanity's most exciting science goals. The discovery of super Earths, terrestrial planets more massive than Earth, has opened a new era in exoplanet science, confirming the basic idea that our solar system is not the only planetary system to harbor

V. Meadows; S. Seager

2010-01-01

166

Terrestrial Planet Geophysics  

NASA Astrophysics Data System (ADS)

Terrestrial planet geophysics beyond our home sphere had its start arguably in the early 1960s, with Keith Runcorn contending that the second-degree shape of the Moon is due to convection and Mariner 2 flying past Venus and detecting no planetary magnetic field. Within a decade, in situ surface geophysical measurements were carried out on the Moon with the Apollo program, portions of the lunar magnetic and gravity fields were mapped, and Jack Lorell and his colleagues at JPL were producing spherical harmonic gravity field models for Mars using tracking data from Mariner 9, the first spacecraft to orbit another planet. Moreover, Mariner 10 discovered a planetary magnetic field at Mercury, and a young Sean Solomon was using geological evidence of surface contraction to constrain the thermal evolution of the innermost planet. In situ geophysical experiments (such as seismic networks) were essentially never carried out after Apollo, although they were sometimes planned just beyond the believability horizon in planetary mission queues. Over the last three decades, the discipline of terrestrial planet geophysics has matured, making the most out of orbital magnetic and gravity field data, altimetric measurements of surface topography, and the integration of geochemical information. Powerful constraints are provided by tectonic and volcanic information gleaned from surface images, and the engagement of geologists in geophysical exercises is actually quite useful. Accompanying these endeavors, modeling techniques, largely adopted from the Earth Science community, have become increasingly sophisticated and have been greatly enhanced by the dramatic increase in computing power over the last two decades. The future looks bright with exciting new data sets emerging from the MESSENGER mission to Mercury, the promise of the GRAIL gravity mission to the Moon, and the re-emergence of Venus as a worthy target for exploration. Who knows? With the unflagging optimism and persistence of a few diehards, we may eventually have a seismic and heat flow network on Mars.

Phillips, R. J.

2008-12-01

167

Physics of Extra Dimensions Final Report  

SciTech Connect

We provide the final report for Csaba Csaki's OJI project on "Physics of extra dimensions". It includes the summary of results of higgsless electroweak symmetry breaking, gauge-higgs unification, AdS/QCD and holographic technicolor, and chiral lattice theories from warped extra dimensions.

Csaba Csaki

2007-12-19

168

Solar system constraints on a Rindler-type extra-acceleration from modified gravity at large distances  

SciTech Connect

We analytically work out the orbital effects caused by a Rindler-type extra-acceleration A{sub Rin} which naturally arises in some recent models of modified gravity at large distances. In particular, we focus on the perturbations induced by it on the two-body range ? and range-rate ?-dot which are commonly used in satellite and planetary investigations as primary observable quantities. The constraints obtained for A{sub Rin} by comparing our calculations with the currently available range and range-rate residuals for some of the major bodies of the solar system, obtained without explicitly modeling A{sub Rin}, are 1–2 × 10{sup ?13} m s{sup ?2} (Mercury and Venus), 1 × 10{sup ?14} m s{sup ?2} (Saturn), 1 × 10{sup ?15} m s{sup ?2} (Mars), while for a terrestrial Rindler acceleration we have an upper bound of 5 × 10{sup ?16} m s{sup ?2} (Moon). The constraints inferred from the planets' range and range-rate residuals are confirmed also by the latest empirical determinations of the corrections ?dot varpi to the usual Newtonian/Einsteinian secular precessions of the planetary longitudes of perihelia varpi: moreover, the Earth yields A{sub Rin} ? 7 × 10{sup ?16} m s{sup ?2}. Another approach which could be followed consists of taking into account A{sub Rin} in re-processing all the available data sets with accordingly modified dynamical models, and estimating a dedicated solve-for parameter explicitly accounting for it. Anyway, such a method is time-consuming. A preliminary analysis likely performed in such a way by a different author yields A ? 8 × 10{sup ?14} m s{sup ?2} at Mars' distance and A ? 1 × 10{sup ?14} m s{sup ?2} at Saturn's distance. The method adopted here can be easily and straightforwardly extended to other long-range modified models of gravity as well.

Iorio, L., E-mail: lorenzo.iorio@libero.it [Ministero dell'Istruzione, dell'Università e della Ricerca (M.I.U.R.), Fellow of the Royal Astronomical Society (F.R.A.S.), viale Unità d'Italia 68, 70125 Bari (Italy)

2011-05-01

169

Planetary habitability: lessons learned from terrestrial analogues  

NASA Astrophysics Data System (ADS)

Terrestrial analogue studies underpin almost all planetary missions and their use is essential in the exploration of our Solar system and in assessing the habitability of other worlds. Their value relies on the similarity of the analogue to its target, either in terms of their mineralogical or geochemical context, or current physical or chemical environmental conditions. Such analogue sites offer critical ground-truthing for astrobiological studies on the habitability of different environmental parameter sets, the biological mechanisms for survival in extreme environments and the preservation potential and detectability of biosignatures. The 33 analogue sites discussed in this review have been selected on the basis of their congruence to particular extraterrestrial locations. Terrestrial field sites that have been used most often in the literature, as well as some lesser known ones which require greater study, are incorporated to inform on the astrobiological potential of Venus, Mars, Europa, Enceladus and Titan. For example, the possibility of an aerial habitable zone on Venus has been hypothesized based on studies of life at high-altitudes in the terrestrial atmosphere. We also demonstrate why many different terrestrial analogue sites are required to satisfactorily assess the habitability of the changing environmental conditions throughout Martian history, and recommend particular sites for different epochs or potential niches. Finally, habitable zones within the aqueous environments of the icy moons of Europa and Enceladus and potentially in the hydrocarbon lakes of Titan are discussed and suitable analogue sites proposed. It is clear from this review that a number of terrestrial analogue sites can be applied to multiple planetary bodies, thereby increasing their value for astrobiological exploration. For each analogue site considered here, we summarize the pertinent physiochemical environmental features they offer and critically assess the fidelity with which they emulate their intended target locale. We also outline key issues associated with the existing documentation of analogue research and the constraints this has on the efficiency of discoveries in this field. This review thus highlights the need for a global open access database for planetary analogues.

Preston, Louisa J.; Dartnell, Lewis R.

2014-01-01

170

Utility terrestrial biodiversity issues  

SciTech Connect

Results from a survey of power utility biologists indicate that terrestrial biodiversity is considered a major issued by only a few utilities; however, a majority believe it may be a future issue. Over half of the respondents indicated that their company is involved in some management for biodiversity, and nearly all feel that it should be a goal for resource management. Only a few utilities are funding biodiversity research, but a majority felt more research was needed. Generally, larger utilities with extensive land holdings had greater opportunities and resources for biodiversity management. Biodiversity will most likely be a concern with transmission rights-of-way construction and maintenance, endangered species issues and general land resource management, including mining reclamation and hydro relicensing commitments. Over half of the companies surveyed have established voluntary partnerships with management groups, and biodiversity is a goal in nearly all the joint projects. Endangered species management and protection, prevention of forest fragmentation, wetland protection, and habitat creation and protection are the most common partnerships involving utility companies. Common management practices and unique approaches are presented, along with details of the survey. 4 refs.

Breece, G.A. [Southern Company, Atlanta, GA (United States); Ward, B.J. [Carolina Power and Light Company, Raleigh, NC (United States)

1996-11-01

171

Metabolic assessments during extra-vehicular activity.  

PubMed

Extra-vehicular activity (EVA) has a significant role during extended space flights. It demonstrates that humans can survive and perform useful work outside the Orbital Space Stations (OSS) while wearing protective space suits (SS). When the International Space Station 'Alpha' (ISSA) is fully operational, EVA assembly, installation, maintenance and repair operations will become an everyday repetitive work activity in space. It needs new ergonomic evaluation of the work/rest schedule for an increasing of the labor amount per EVA hour. The metabolism assessment is a helpful method to control the productivity of the EVA astronaut and to optimize the work/rest regime. Three following methods were used in Russia to estimate real-time metabolic rates during EVA: 1. Oxygen consumption, computed from the pressure drop in a high pressure bottle per unit time (with actual thermodynamic oxygen properties under high pressure and oxygen leakage taken into account). 2. Carbon dioxide production, computed from CO2 concentration at the contaminant control cartridge and gas flow rate in the life support subsystem closed loop (nominal mode) or gas leakage in the SS open loop (emergency mode). 3. Heat removal, computed from the difference between the temperatures of coolant water or gas and its flow rate in a unit of time (with assumed humidity and wet oxygen state taken into account). Comparison of heat removal values with metabolic rates enables us to determine the thermal balance during an operative medical control of EVA at "Salyut-6", "Salyut-7" and "Mir" OSS. Complex analysis of metabolism, body temperature and heat rate supports a differential diagnosis between emotional and thermal components of stress during EVA. It gives a prognosis of human homeostasis during EVA. Available information has been acquired into an EVA data base which is an effective tool for ergonomical optimization. PMID:11541598

Osipov YuYu; Spichkov, A N; Filipenkov, S N

1998-01-01

172

Metabolic assessments during extra-vehicular activity  

NASA Astrophysics Data System (ADS)

Extra-vehicular activity (EVA) has a significant role during extended space flights. It demonstrates that humans can survive and perform useful work outside the Orbital Space Stations (OSS) while wearing protective space suits (SS). When the International Space Station 'Alpha'(ISSA) is fully operational, EVA assembly, installation, maintenance and repair operations will become an everyday repetitive work activity in space. It needs new ergonomic evaluation of the work/rest schedule for an increasing of the labor amount per EVA hour. The metabolism assessment is a helpful method to control the productivity of the EVA astronaut and to optimize the work/rest regime. Three following methods were used in Russia to estimate real-time metabolic rates during EVA: 1. Oxygen consumption, computed from the pressure drop in a high pressure bottle per unit time (with actual thermodynamic oxygen properties under high pressure and oxygen leakage taken into account). 2. Carbon dioxide production, computed from CO 2 concentration at the contaminant control cartridge and gas flow rate in the life support subsystem closed loop (nominal mode) or gas leakage in the SS open loop (emergency mode). 3. Heat removal, computed from the difference between the temperatures of coolant water or gas and its flow rate in a unit of time (with assumed humidity and wet oxygen state taken into account). Comparison of heat removal values with metabolic rates enables us to determine the thermal balance during an operative medical control of EVA at "Salyut-6", "Salyut-7" and "Mir" OSS. Complex analysis of metabolism, body temperature and heat rate supports a differential diagnosis between emotional and thermal components of stress during EVA. It gives a prognosis of human homeostasis during EVA. Available information has been acquired into an EVA data base which is an effective tool for ergonomical optimization.

Osipov, Yu. Yu.; Spichkov, A. N.; Filipenkov, S. N.

173

Contaminant Exposure in Terrestrial Vertebrates  

EPA Science Inventory

Manuscript is a critical review of the state of the science for quantifying exposures of terrestrial wildlife species to chemical contamination. It describes the unique aspects of birds, mammals, reptiles, amphibians and threatened and endangered species. Fate and transport of ...

174

USING TERRESTRIAL PLANTS IN BIOMONITORING  

EPA Science Inventory

Terrestrial plants have been used as monitors of environmental pollutants since at least the beginning of this century & have recently received attention in response to the need for ecological assessments at hazardous waste sites & monitoring pesticide damage to nontarget plants....

175

Radiocarbon dating of terrestrial carbonates  

USGS Publications Warehouse

Terrestrial carbonates encompass a wide range of materials that potentially could be used for radiocarbon (14C) dating. Biogenic carbonates, including shells and tests of terrestrial and aquatic gastropods, bivalves, ostracodes, and foraminifera, are preserved in a variety of late Quaternary deposits and may be suitable for 14C dating. Primary calcareous deposits (marls, tufa, speleothems) and secondary carbonates (rhizoliths, fracture fill, soil carbonate) may also be targeted for dating when conditions are favorable. This chapter discusses issues that are commonly encountered in 14C dating of terrestrial carbonates, including isotopic disequilibrium and open-system behavior, as well as methods used to determine the reliability of ages derived from these materials. Recent methodological advancements that may improve the accuracy and precision of 14C ages of terrestrial carbonates are also highlighted.

Pigati, Jeffrey S.

2014-01-01

176

GEOLogic: Terrestrial and Jovian Planets  

NSDL National Science Digital Library

In this two-part example, students are given clues about properties about the terrestrial and Jovian planets respectively and asked to match up the planet with the correct equatorial radius, mean orbital velocity, and period of rotation.

Laura Guertin

177

PIL B v3 11/1/11 USE OF EXTRA SAMPLES FOR RESEARCH PURPOSES  

E-print Network

. In addition, healthcare professionals need to study tissue or fluids as part of their training. How. One of our team will go through the information sheet with you and answer any questions you have to patients in the future. What happens to the extra samples taken? A healthcare professional may remove body

178

HYDROTHERMAL VENT COMPLEXES AND THE SEARCH FOR EXTRA-TERRESTRIAL WATER. H. Svensen1  

E-print Network

. They comprise up to 7 km deep pipe structures filled with brecciated sedimentary rocks (Fig. 1). Some also con is generally inferred from particular sedimentary structures using an Earth analogy. We present the ex- tra's) are identified in major sedimentary basins in Europe and Africa, directly linked to the presence of water

Mazzini, Adriano

179

ELF and VLF observations of ionospheric disturbances caused by extra-terrestrial origin  

NASA Astrophysics Data System (ADS)

Very Low Frequency (VLF) radio wave propagates within the Earth-ionosphere waveguide, and hence measurement of the VLF amplitude and phase can be utilized to study physics of phenomena taking place in the lower ionosphere below about 100 km. Observation of Extremely Low Frequency (ELF) radio wave is also a powerful tool to investigate ionospheric phenomena such as lightning. Here we present ELF and VLF observations of ionospheric disturbances caused by extraterrestrial phenomena. Cosmological Gamma-ray bursts has already been known as the origin of ionospheric disturbances. In addition to this, "magnetar" flares has also been recognized to affect the Earth's ionosphere. Ordinary neutron stars possess magnetic fields of about 10^12 Gauss, while magnetars are considered to have extremely strong magnetic fields of about 10^15 G. Some of the magnetars emit short-duration (~0.1 s) gamma-ray bursts repeatedly in active phases, thereby they are named as "Soft Gamma-ray Repeaters (SGRs)". As rare events, SGRs emit exceptionally bright gamma-ray flares "giant flares", whose peak fluxes exceed those of X-class large solar flares by several order of magnitudes. Recent sensitive measurement of ELF and VLF radio waves can observe ionospheric disturbances caused by these short-repeated and giant flares. Namely, we have found that transient ELF radio wave and Schumann resonance were caused by SGR giant flares in 2004. The emission mechanism is still unclear, but similarity of nuclear detonation in 1960's might give some hints to unveil the emission mechanism. Interesting application of VLF measurement of magnetar flare is that we can deduce the gamma-ray spectrum from VLF data. Intensive astronomical X-ray and gamma-ray observations have been performed by satellites in space using very sensitive detectors. Since SGR giant flare emits huge X-ray/gamma-ray flux, such sensitive detectors are affected by severe saturation problems and precise measurement is very difficult. In my presentation, we present how we deduce the photon spectrum from the VLF data. Using Monte Carlo method, we modeled ionization of lower ionosphere, and obtained altitude profile of electron number density. We then utilized Finite-Difference Time Domain (FDTD) method to simulate VLF propagation. The altitude profile and simulated amplitude change differs depending on the energy spectrum. Therefore, by comparing simulation results with the observation, we can infer the source spectrum as an inverse problem.

Tanaka, Y.; Hayakawa, M.; Hobara, Y.; Raulin, J.; Takahashi, Y.; Sato, M.; Terasawa, T.

2013-05-01

180

Meteorological and extra-terrestrial causes of the daily variation of cosmic ray intensity  

Microsoft Academic Search

Summary  The daily variations of total cosmic ray intensity and the intensities of meson and electron components have been studied\\u000a at Alimedabad with vertical geiger counter telescopes. The influence of meteorological factors on these variations has been\\u000a examined, and it has been found that appropriate barometric coefficients for correcting the cosmic ray intensities can be\\u000a obtained from a consideration of the

V. Sarabhai; U. D. Desai; R. P. Kane

1953-01-01

181

Search for Extra-Terrestrial planets: The DARWIN mission - Target Stars and Array Architectures  

E-print Network

The DARWIN mission is an Infrared free flying interferometer mission based on the new technique of nulling interferometry. Its main objective is to detect and characterize other Earth-like planets, analyze the composition of their atmospheres and their capability to sustain life, as we know it. DARWIN is currently in definition phase. This PhD work that has been undertaken within the DARWIN team at the European Space Agency (ESA) addresses two crucial aspects of the mission. Firstly, a DARWIN target star list has been established that includes characteristics of the target star sample that will be critical for final mission design, such as, luminosity, distance, spectral classification, stellar variability, multiplicity, location and radius of the star. Constrains were applied as set by planet evolution theory and mission architecture. Secondly, a number of alternative mission architectures have been evaluated on the basis of interferometer response as a function of wavelength, achievable modulation efficiency, number of telescopes and starlight rejection capabilities. The study has shown that the core mission goals should be achievable with a lower level of complexity as compared to the current baseline configuration.

Lisa Kaltenegger

2005-04-22

182

Theoretical Studies of the Extra-terrestrial Chemistry of Biogenic Elements and Compounds  

NASA Technical Reports Server (NTRS)

Results are presented on the following:(A) Ab initio quantum chemical studies of reactions in astrophysical ices.Theoretical electronic structure calculations were used to investigate reactions between formaldehyde (H2CO) and both hydrogen cyanide (HCN) and isocyanide (HNC) in search of other favorable reactions such as ammonia-formaldehyde addition, which was found in a recent theoretical study to be strongly enhanced when it occurs within cold ices.The present study examines further reactions between this product and H2CO in ices.(B) Heterogeneous hydrogenation of CO and H2CO on icy grain mantles.Formaldehyde (H2CO) and methanol (CH30H) are thought to be produced in the interstellar medium by the successive hydrogenation of carbon monoxide (CO) on grain surfaces. In the gas phase, the steps in which H adds to CO and H2CO possess modest barriers and are too inefficient to account for the observed abundances. Recent laboratory work has confirmed that formaldehyde and methanol are formed when H atoms are deposited on CO ice at 12 K. The present study employed ab initio quantum chemical calculations to investigate the impact of water ice on the sequential hydrogenation of CO.(C) Ice-bound condensed-phase reactions involving formic acid (HCOOH), methylenimine (CH2NH), hydrogen cyanide (HCN), hydrogen isocyanide (HNC), and ammonia ( 3) were investigated in order to characterize possible pathways to larger organic species that are efficient at the cold temperatures prevalent in cometary nuclei and the interstellar medium. (D) Pathways to glycine and other amino acids in ultraviolet-irradiated ices determined via quantum chemical modeling.(E) Photoionization in ultraviolet processing of astrophysical ice analogs at cryogenic temperatures.

Woon, David E.

2003-01-01

183

Combustion of Metals in Reduced-Gravity and Extra Terrestrial Environments  

NASA Technical Reports Server (NTRS)

The combustion of metals is a field with important practical applications in rocket propellants, high-temperature flames, and material synthesis. Also, the safe operation of metal containers in high-pressure oxygen systems and with cryogenic fuels and oxidizers remains an important concern in industry. The increasing use of metallic components in spacecraft and space structures has also raised concerns about their flammability properties and fire suppression mechanisms. In addition, recent efforts to embark on unmanned and manned planetary exploration, such as on Mars, have also renewed the interest in metal/carbon-dioxide combustion as an effective in situ resource utilization technology. In spite of these practical applications, the understanding of the combustion properties of metals remains far behind that of the most commonly used fuels such as hydrocarbons. The lack of understanding is due to the many problems unique to metal- oxidizer reactions such as: low-temperature surface oxidation prior to ignition, heterogeneous reactions, very high combustion temperatures, product condensation, high emissivity of products, and multi-phase interactions. Very few analytical models (all neglecting the influence of gravity) have been developed to predict the burning characteristics and the flame structure details. Several experimental studies attempting to validate these models have used small metal particles to recreate gravity-free conditions. The high emissivity of the flames, rapid reaction, and intermittent explosions experienced by these particles have made the gathering of any useful information on burning rates and flame structure very difficult. The use of a reduced gravity environment is needed to clarify some of the complex interactions among the phenomena described above. First, the elimination of the intrusive buoyant flows that plague all combustion phenomena is of paramount importance in metal reactions due to the much higher temperatures reached during combustion. Second, a low-gravity environment is absolutely essential to remove the destructive effect of gravity on the shape of a molten metal droplet in order to study a spherically symmetric condition with large bulk samples. The larger size of the spherical metal droplet and the longer burning times available in reduced gravity extend the spatial and temporal dimensions to permit careful probing of the flame structure and dynamics. Third, the influence of the radiative heat transfer from the solid oxides can be studied more carefully by generating a stagnant spherical shell of condensed products undisturbed by buoyancy.

Branch, M.C.; Abbud-Madrid, A.; Daily, J. W.

1999-01-01

184

Sliding GAIT Algorithm for the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE)  

NASA Technical Reports Server (NTRS)

The design of a surface robotic system typically involves a trade between the traverse speed of a wheeled rover and the terrain-negotiating capabilities of a multi-legged walker. The ATHLETE mobility system, with both articulated limbs and wheels, is uniquely capable of both driving and walking, and has the flexibility to employ additional hybrid mobility modes. This paper introduces the Sliding Gait, an intermediate mobility algorithm faster than walking with better terrain-handling capabilities than wheeled mobility.

Townsend, Julie; Biesiadecki, Jeffrey

2012-01-01

185

Fish out of water: terrestrial jumping by fully aquatic fishes.  

PubMed

Many teleosts that live at the water's edge will voluntarily strand themselves to evade predators or escape poor conditions-this behavior has been repeatedly observed in the field for killifishes (Cyprinodontiformes). Although most killifishes are considered fully aquatic and possess no obvious morphological specializations to facilitate terrestrial locomotion, individuals from several different species have been observed moving across land via a "tail flip" behavior that generates a terrestrial jump. Like aquatic fast starts, terrestrial jumps are produced by high-curvature lateral flexion of the body (stage one), followed by contralateral flexion of the posterior body (stage two). Here, terrestrial jumps and aquatic fast starts are quantified for two littoral teleosts: Gambusia affinis (a killifish, Cyprinodontiformes) and Danio rerio (a small carp, Cypriniformes) to determine if the tail flip is produced by other (non-killifish) teleosts and to test the null hypothesis that the tail flip is a fast start behavior, performed on land. Both Danio and Gambusia produce tail flip-driven terrestrial jumps, which are kinematically distinct from aquatic escapes and characterized by (1) a prolonged stage one, during which the fish bends, lifting and rolling the center of mass over the caudal peduncle, and (2) a relatively brief stage two, wherein the caudal peduncle pushes against the substrate to launch the fish into the aerial phase. The ability of these fully aquatic fishes to employ the same structure to produce distinct kinematic patterns in disparate environments suggests that a new behavior has evolved to facilitate movement on land and that anatomical novelty is not a prerequisite for effective terrestrial locomotion. PMID:21972177

Gibb, Alice C; Ashley-Ross, Miriam A; Pace, Cinnamon M; Long, John H

2011-12-01

186

Workshop on Oxygen in the Terrestrial Planets  

NASA Technical Reports Server (NTRS)

This volume contains abstracts that have been accepted for presentation at the Workshop on Oxygen in the Terrestrial Planets, July 20-23,2004, Santa Fe, New Mexico. The contents include: 1) Experimental Constraints on Oxygen and Other Light Element Partitioning During Planetary Core Formation; 2) In Situ Determination of Fe(3+)/SigmaFe of Spinels by Electron Microprobe: An Evaluation of the Flank Method; 3) The Effect of Oxygen Fugacity on Large-Strain Deformation and Recrystallization of Olivine; 4) Plagioclase-Liquid Trace Element Oxygen Barometry and Oxygen Behaviour in Closed and Open System Magmatic Processes; 5) Core Formation in the Earth: Constraints from Ni and Co; 6) Oxygen Isotopic Compositions of the Terrestrial Planets; 7) The Effect of Oxygen Fugacity on Electrical Conduction of Olivine and Implications for Earth s Mantle; 8) Redox Chemical Diffusion in Silicate Melts: The Impact of the Semiconductor Condition; 9) Ultra-High Temperature Effects in Earth s Magma Ocean: Pt and W Partitioning; 10) Terrestrial Oxygen and Hydrogen Isotope Variations: Primordial Values, Systematics, Subsolidus Effects, Planetary Comparisons, and the Role of Water; 11) Redox State of the Moon s Interior; 12) How did the Terrestrial Planets Acquire Their Water?; 13) Molecular Oxygen Mixing Ratio and Its Seasonal Variability in the Martian Atmosphere; 14) Exchange Between the Atmosphere and the Regolith of Mars: Discussion of Oxygen and Sulfur Isotope Evidence; 15) Oxygen and Hydrogen Isotope Systematics of Atmospheric Water Vapor and Meteoric Waters: Evidence from North Texas; 16) Implications of Isotopic and Redox Heterogeneities in Silicate Reservoirs on Mars; 17) Oxygen Isotopic Variation of the Terrestrial Planets; 18) Redox Exchanges in Hydrous Magma; 19) Hydrothermal Systems on Terrestrial Planets: Lessons from Earth; 20) Oxygen in Martian Meteorites: A Review of Results from Mineral Equilibria Oxybarometers; 21) Non-Linear Fractionation of Oxygen Isotopes Implanted in Lunar Metal Grains: Solar, Lunar or Terrestrial Origin? 22) Isotopic Zoning in the Inner Solar System; 23) Redox Conditions on Small Bodies; 24) Determining the Oxygen Fugacity of Lunar Pyroclastic Glasses Using Vanadium Valence - An Update; 25) Mantle Redox Evolution and the Rise of Atmospheric O2; 26) Variation of Kd for Fe-Mg Exchange Between Olivine and Melt for Compositions Ranging from Alkaline Basalt to Rhyolite; 27) Determining the Partial Pressure of Oxygen (PO,) in Solutions on Mars; 28) The Influence of Oxygen Environment on Kinetic Properties of Silicate Rocks and Minerals; 29) Redox Evolution of Magmatic Systems; 30) The Constancy of Upper Mantlefo, Through Time Inferred from V/Sc Ratios in Basalts: Implications for the Rise in Atmospheric 0 2; 31) Nitrogen Solubility in Basaltic Melt. Effects of Oxygen Fugacity, Melt Composition and Gas Speciation; 32) Oxygen Isotope Anomalies in the Atmospheres of Earth and Mars; 33) The Effect of Oxygen Fugacity on Interdiffusion of Iron and Magnesium in Magnesiowiistite 34) The Calibration of the Pyroxene Eu-Oxybarometer for the Martian Meteorites; 35) The Europium Oxybarometer: Power and Pitfalls; 36) Oxygen Fugacity of the Martian Mantle from PigeoniteMelt Partitioning of Samarium, Europium and Gadolinium; 37) Oxidation-Reduction Processes on the Moon: Experimental Verification of Graphite Oxidation in the Apollo 17 Orange Glasses; 38) Oxygen and Core Formation in the Earth; 39) Geologic Record of the Atmospheric Sulfur Chemistry Before the Oxygenation of the Early Earth s Atmosphere; 40) Comparative Planetary Mineralogy: V/(CrCAl) Systematics in Chromite as an Indicator of Relative Oxygen Fugacity; 41) How Well do Sulfur Isotopes Constrain Oxygen Abundance in the Ancient Atmospheres? 42) Experimental Constraints on the Oxygen Isotope (O-18/ O-16) Fractionation in the Ice vapor and Adsorbant vapor Systems of CO2 at Conditions Relevant to the Surface of Mars; 43) Micro-XANES Measurements on Experimental Spinels andhe Oxidation State of Vanadium in Spinel-Melt Pairs; 44) Testing the Magma Ocean Hypothesis Using

2004-01-01

187

Scalar field localization on deformed extra space  

E-print Network

Field localization on 2-dim extra space is considered in the framework of f(R) gravity. It is shown that an interference of local matter energy distribution and a metric of the extra space form a point-like defect - 4-dim brane. The energy-momentum of the brane depends on initial conditions that could lead to the cosmological $\\Lambda$ term being arbitrarily small.

Rubin, Sergey G

2015-01-01

188

Topological interactions in warped extra dimensions  

Microsoft Academic Search

Topological interactions will be generated in theories with compact extra dimensions where fermionic chiral zero modes have\\u000a different localizations. This is the case in many warped extra dimension models where the right-handed top quark is typically\\u000a localized away from the left-handed one. Using deconstruction techniques, we study the topological interactions in these models.\\u000a These interactions appear as trilinear and quadrilinear

Yang Bai; Gustavo Burdman; Christopher T. Hill

2010-01-01

189

Editorial: Focus on Extra Space Dimensions  

NASA Astrophysics Data System (ADS)

Experiments at the Large Hadron Collider (LHC) have just started. In addition to verifying the Standard Model (SM) of particle physics, these experiments will probe a new energy frontier and test extensions of the SM. The existence of extra dimensions is one of the most attractive possibilities for physics beyond the SM. This focus issue contains a collection of articles addressing both theoretical and phenomenological aspects of extra-dimensional models. Focus on Extra Space Dimensions Contents Minimal universal extra dimensions in CalcHEP/CompHEP AseshKrishna Datta, Kyoungchul Kong and Konstantin T Matchev Disordered extra dimensions Karim Benakli Codimension-2 brane-bulk matching: examples from six and ten dimensions Allan Bayntun, C P Burgess and Leo van Nierop Gauge threshold corrections in warped geometry Kiwoon Choi, Ian-Woo Kim and Chang Sub Shin Holographic methods and gauge-Higgs unification in flat extra dimensions Marco Serone Soft-wall stabilization Joan A Cabrer, Gero von Gersdorff and Mariano Quirós Warped five-dimensional models: phenomenological status and experimental prospects Hooman Davoudiasl, Shrihari Gopalakrishna, Eduardo Pontón and José Santiago

Agashe, Kaustubh; Pomarol, Alex

2010-07-01

190

Grazers: biocatalysts of terrestrial silica cycling  

PubMed Central

Silica is well known for its role as inducible defence mechanism countering herbivore attack, mainly through precipitation of opaline, biogenic silica (BSi) bodies (phytoliths) in plant epidermal tissues. Even though grazing strongly interacts with other element cycles, its impact on terrestrial silica cycling has never been thoroughly considered. Here, BSi content of ingested grass, hay and faeces of large herbivores was quantified by performing multiple chemical extraction procedures for BSi, allowing the assessment of chemical reactivity. Dissolution experiments with grass and faeces were carried out to measure direct availability of BSi for dissolution. Average BSi and readily soluble silica numbers were higher in faeces as compared with grass or hay, and differences between herbivores could be related to distinct digestive strategies. Reactivity and dissolvability of BSi increases after digestion, mainly due to degradation of organic matrices, resulting in higher silica turnover rates and mobilization potential from terrestrial to aquatic ecosystems in non-grazed versus grazed pasture systems (2 versus 20 kg Si ha?1 y?1). Our results suggest a crucial yet currently unexplored role of herbivores in determining silica export from land to ocean, where its availability is linked to eutrophication events and carbon sequestration through C–Si diatom interactions. PMID:24107532

Vandevenne, Floor Ina; Barão, Ana Lúcia; Schoelynck, Jonas; Smis, Adriaan; Ryken, Nick; Van Damme, Stefan; Meire, Patrick; Struyf, Eric

2013-01-01

191

Extra-oral halitosis: an overview.  

PubMed

Halitosis can be subdivided into intra-oral and extra-oral halitosis, depending on the place where it originates. Most reports now agree that the most frequent sources of halitosis exist within the oral cavity and include bacterial reservoirs such as the dorsum of the tongue, saliva and periodontal pockets, where anaerobic bacteria degrade sulfur-containing amino acids to produce the foul smelling volatile sulfur compounds (VSCs), especially hydrogen sulfide (H(2)S) and methyl mercaptan (CH(3)SH). Tongue coating is considered to be the most important source of VSCs. Oral malodor can now be treated effectively. Special attention in this overview is given to extra-oral halitosis. Extra-oral halitosis can be subdivided into non-blood-borne halitosis, such as halitosis from the upper respiratory tract including the nose and from the lower respiratory tract, and blood-borne halitosis. The majority of patients with extra-oral halitosis have blood-borne halitosis. Blood-borne halitosis is also frequently caused by odorous VSCs, in particular dimethyl sulfide (CH3SCH3). Extra-oral halitosis, covering about 5-10% of all cases of halitosis, might be a manifestation of a serious disease for which treatment is much more complicated than for intra-oral halitosis. It is therefore of utmost importance to differentiate between intra-oral and extra-oral halitosis. Differences between intra-oral and extra-oral halitosis are discussed extensively. The importance of applying odor characterization of various odorants in halitosis research is also highlighted in this article. The use of the odor index, odor threshold values and simulation of bad breath samples is explained. PMID:21386205

Tangerman, A; Winkel, E G

2010-03-01

192

A numerical simulation of the formation of the terrestrial planets  

Microsoft Academic Search

A numerical simulation of the accumulation of the terrestrial planets was performed, starting with 200 lunar-size planetesimals distributed uniformly in a plane; these were placed in circular orbits around the sun between 0.5 and 1.5 AU, with the aim that they would form Venus and earth by inelastic collisions. The rule was that when two bodies physically collided, they coalesced

M. Lecar; S. J. Aarseth

1986-01-01

193

Terrestrial ecosystems and climatic change  

SciTech Connect

The structure and function of terrestrial ecosystems depend on climate, and in turn, ecosystems influence atmospheric composition and climate. A comprehensive, global model of terrestrial ecosystem dynamics is needed. A hierarchical approach appears advisable given currently available concepts, data, and formalisms. The organization of models can be based on the temporal scales involved. A rapidly responding model describes the processes associated with photosynthesis, including carbon, moisture, and heat exchange with the atmosphere. An intermediate model handles subannual variations that are closely associated with allocation and seasonal changes in productivity and decomposition. A slow response model describes plant growth and succession with associated element cycling over decades and centuries. These three levels of terrestrial models are linked through common specifications of environmental conditions and constrain each other. 58 refs.

Emanuel, W.R. (Oak Ridge National Lab., TN (USA)); Schimel, D.S. (Colorado State Univ., Fort Collins, CO (USA). Natural Resources Ecology Lab.)

1990-01-01

194

Utilization of the terrestrial cyanobacteria  

NASA Astrophysics Data System (ADS)

The terrestrial, N _{2}-fixing cyanobacterium, Nostoc commune has expected to utilize for agriculture, food and terraforming cause of its extracellular polysaccharide, desiccation tolerance and nitrogen fixation. Previously, the first author indicated that desiccation related genes were analyzed and the suggested that the genes were related to nitrogen fixation and metabolisms. In this report, we suggest possibility of agriculture, using the cyanobacterium. Further, we also found radioactive compounds accumulated N. commune (cyanobacterium) in Fukushima, Japan after nuclear accident. Thus, it is investigated to decontaminate radioactive compounds from the surface soil by the cyanobacterium and showed to accumulate radioactive compounds using the cyanobacterium. We will discuss utilization of terrestrial cyanobacteria under closed environment. Keyword: Desiccation, terrestrial cyanobacteria, bioremediation, agriculture

Katoh, Hiroshi; Tomita-Yokotani, Kaori; Furukawa, Jun; Kimura, Shunta; Yokoshima, Mika; Yamaguchi, Yuji; Takenaka, Hiroyuki

195

Groundwater and Terrestrial Water Storage  

NASA Technical Reports Server (NTRS)

Groundwater is a vital resource and also a dynamic component of the water cycle. Unconfined aquifer storage is less responsive to short term weather conditions than the near surface terrestrial water storage (TWS) components (soil moisture, surface water, and snow). However, save for the permanently frozen regions, it typically exhibits a larger range of variability over multi-annual periods than the other components. Groundwater is poorly monitored at the global scale, but terrestrial water storage (TWS) change data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission are a reasonable proxy for unconfined groundwater at climatic scales.

Rodell, Matthew; Chambers, Don P.; Famiglietti, James S.

2012-01-01

196

Adapting the GISS Climate GCM to Model Extra-Solar Climate Regimes  

NASA Astrophysics Data System (ADS)

Hundreds of extra-solar planets have been discovered by NASA's Kepler mission, some potentially habitable, most exhibiting extremes in climate beyond current modeling experience. Zero-order assessment of the stellar type and the planet's distance from the star serves to identify the ballpark of whether silicon dioxide is likely to be in gaseous or liquid phase in the planet's atmosphere, or a part of the solid planetary ground surface. A lot of first-order modeling would involve assessing the chemical limitations to establish the likely chemical composition of the planetary atmosphere. For a more detailed analysis of the prevailing climate on an extra-solar planet a 3-D global climate model would be required. We begin the Extra-Solar Climate Model development by starting the with GISS Climate GCM by having key model parameters be expressed in physics based terms rather than Earth specific parameters. Examples of such key parameters are: the Planet's mass and radius, mass and composition of the atmosphere, Star-Planet distance, rotation rate and orbital parameters, stellar spectral distribution, land topography, and land-ocean distribution. These are parameters that are more or less straight forward to redefine for extra-solar conditions that are not greatly different for what may be considered as the ';habitable' zone. We present extreme climate simulations ranging from snowball Earth conditions to near-runaway greenhouse conditions. The objective of this modeling study is the development of a more physically based climate model that will be adaptable for assessing habitable climate regimes on newly discovered extra-solar planets, and will also facilitate the study terrestrial climate system analysis in paleoclimate applications.

Lacis, A. A.

2013-12-01

197

A Thermal Graviton Background from Extra Dimensions  

E-print Network

Inflationary cosmology predicts a low-amplitude graviton background across a wide range of frequencies. This Letter shows that if one or more extra dimensions exist, the graviton background may have a thermal spectrum instead, dependent on the fundamental scale of the extra dimensions. The energy density is shown to be significant enough that it can affect nucleosynthesis in a substantial way. The possibility of direct detection of a thermal graviton background using the 21-cm hydrogen line is discussed. Alternative explanations for the creation of a thermal graviton background are also examined.

E. R. Siegel; J. N. Fry

2005-04-05

198

Statistical analysis for extra galactic exoplanets  

NASA Astrophysics Data System (ADS)

We present the first statistical analysis on extra galactic stars that could host an exoplanet. We analyze the photometric data of the Ursa Minor Dwarf Spheroidal galaxy, taken by the Isaac Newton Group of Telescopes (INT) and we calculate the probability to detect a planetary transit , based on the stellar characteristics of the statistical sample and the transit detection probability distribution. Our goal is to determine how many possible planets could be detected in the galaxy and therefore create the first catalogue of extra galactic exoplanet host star candidates for future space missions.

Karpouzas, K.

2013-09-01

199

Microscopic Primordial Black Holes and Extra Dimensions  

SciTech Connect

We examine the production and evolution of microscopic black holes in the early universe in the large extra dimensions scenario. We demonstrate that, unlike in the standard four-dimensional cosmology, in large extra dimensions absorption of matter from the primordial plasma by the black holes is significant and can lead to rapid growth of the black hole mass density. This effect can be used to constrain the conditions present in the very early universe. We demonstrate that this constraint is applicable in regions of parameter space not excluded by existing bounds.

Conley, John A.; Wizansky, Tommer

2006-11-15

200

NewsHour Extra: Addressing Health Mysteries  

NSDL National Science Digital Library

In this PBS NewsHour Extra lesson plan, students take an in-depth look at the SARS epidemic, with a particular focus on pan-national public health administration. A NewsHour interview with Dr. David Heyman, Director for Communicable Diseases at the World Health Organization (WHO), forms the basis of the exercise (video, audio, and transcript available). A NewsHour Extra story on SARS provides additional material. The site also offers ideas for homework and extension activities, each designed to help students explore and understand the process by which organizations like WHO tackle new disease outbreaks.

Dufour, Joanne.

201

Terrestrial atmosphere, water and astrobiology  

Microsoft Academic Search

Primitive life, defined as a chemical system capable to transfer its molecular information via self-replication and also capable to evolve, originated about 4 billion years ago from the processing of organic molecules by liquid water. Terrestrial atmosphere played a key role in the process by allowing the permanent presence of liquid water and by participating in the production of carbon-based

A. Brack; M. Coradini

2010-01-01

202

Scientist Using Terrestrial Lidar Equipment  

USGS Multimedia Gallery

Chris Soulard using the Terrestrial Lidar to scan study area in the Grand Canyon-Parashant National Monument, AZ.  Note the bag of ice on the equipment.  High temperates can cause equipment to overheat, requiring scientists to be creative in protecting equipment....

203

Carbon dioxide and terrestrial ecosystems  

Microsoft Academic Search

This book is a summary of the current research which addresses the effects of elevated carbon dioxide on terrestrial ecosystems and an identification of significant unresolved issues. Chapters address the carbon dioxide effects on trees and forests, unmanaged herbaceous ecosystems, and crops. Included are experimental studies, conceptual models, general mathematical models, dynamic simulation models.

G. W. Koch; H. A. Mooney

1996-01-01

204

Solar Variability and Terrestrial Climate  

NASA Astrophysics Data System (ADS)

The thermal conditions on Planet Earth are primarily the function of the energy in- put from the Sun. The variations in climate on Planet Earth is, however, primarily the function of the redistribution and reorganisation of the internal terrestrial heat balance. Solar variability may affect terrestrial climate (1) by direct changes in irradiance, a fac- tor, however, which is known to be very small, (2) by the solar wind interaction with the geomagnetic field increasing and decreasing the shielding capacity to infalling cosmic-ray, which is known to affect the formation of clouds thereby also affecting global terrestrial climat, and (3) by the solar wind interaction with the geomagnetic field leading to changes in the EarthSs rate of rotation which affect ocean and atmo- sphere circulation thereby also affecting global climate (and sea level). INTAS Project 97-301008 concerns the interaction between geomagnetic field changes and global climatic changes. No doubts, we see important links between externally and internally driven changes in the EarthSs geomagnetic field and changes in terrestrial climate.

Mörner, N.-A.

205

Ionospheres of the terrestrial planets  

Microsoft Academic Search

The theory and observations relating to the ionospheres of the terrestrial planets Venus, the earth and Mars are reviewed. Emphasis is placed on comparing the basic differences and similarities between the planetary ionospheres. The review covers the plasma and electric-magnetic field environments that surround the planets, the theory leading to the creation and transport of ionization in the ionspheres, the

R. W. Schunk; A. F. Nagy

1980-01-01

206

Gigantism, temperature and metabolic rate in terrestrial poikilotherms  

PubMed Central

The mechanisms dictating upper limits to animal body size are not well understood. We have analysed body length data for the largest representatives of 24 taxa of terrestrial poikilotherms from tropical, temperate and polar environments. We find that poikilothermic giants on land become two–three times shorter per each 10 degrees of decrease in ambient temperature. We quantify that this diminution of maximum body size accurately compensates the drop of metabolic rate dictated by lower temperature. This supports the idea that the upper limit to body size within each taxon can be set by a temperature-independent critical minimum value of mass-specific metabolic rate, a fall below which is not compatible with successful biological performance. PMID:16191647

Makarieva, Anastassia M; Gorshkov, Victor G; Li, Bai-Lian

2005-01-01

207

CARBON DIOXIDE SEQUESTRATION IN TERRESTRIAL ECOSYSTEMS  

EPA Science Inventory

The terrestrial biosphere plays a prominent role in the global carbon (C) cycle. errestrial ecosystems are currently accumulating C and it appears feasible to manage existing terrestrial (forest, agronomic, desert) ecosystems to maintain or increase C storage. orest ecosystems ca...

208

Formation of the terrestrial planets from planetesimals  

NASA Technical Reports Server (NTRS)

Formation of the terrestrial planets from planetesimals is discussed. The following subject areas are covered: (1) formation of the original planetesimals; (2) growth of planetesimals into planetary embryos; and (3) growth of runaway planetary embryos into terrestrial planets.

Wetherill, George W.

1991-01-01

209

The Oldest Caseid Synapsid from the Late Pennsylvanian of Kansas, and the Evolution of Herbivory in Terrestrial Vertebrates  

PubMed Central

The origin and early evolution of amniotes (fully terrestrial vertebrates) led to major changes in the structure and hierarchy of terrestrial ecosystems. The first appearance of herbivores played a pivotal role in this transformation. After an early bifurcation into Reptilia and Synapsida (including mammals) 315 Ma, synapsids dominated Paleozoic terrestrial vertebrate communities, with the herbivorous caseids representing the largest vertebrates on land. Eocasea martini gen. et sp. nov., a small carnivorous caseid from the Late Carboniferous, extends significantly the fossil record of Caseidae, and permits the first clade-based study of the origin and initial evolution of herbivory in terrestrial tetrapods. Our results demonstrate for the first time that large caseid herbivores evolved from small, non-herbivorous caseids. This pattern is mirrored by three other clades, documenting multiple, independent, but temporally staggered origins of herbivory and increase in body size among early terrestrial tetrapods, leading to patterns consistent with modern terrestrial ecosystem. PMID:24739998

Reisz, Robert R.; Fröbisch, Jörg

2014-01-01

210

Jan 23 Terrestrial Forest Biomes of the World Terrestrial Forest Biomes of the World  

E-print Network

Jan 23 Terrestrial Forest Biomes of the World #12;Terrestrial Forest Biomes of the World Chapin et al. 2011. Fig 2.24 #12;Terrestrial Forest Biomes of the World Chapin et al. 2011. Fig 2.24 Biome Wildlife Fund Terrestrial Biomes and Biogeographic Realms of the World #12;Climate Controls on Biomes

Hansen, Andrew J.

211

Dissolved Organic Carbon in Terrestrial Ecosystems: Synthesis  

E-print Network

to aquatic ecosystems. De- spite their importance for terrestrial and aquatic biogeochemistry, these fluxes fluxes associated with primary productivity or heterotro- phic respirations in terrestrial systems (for transport from terrestrial environments repre- sents a substantial component of the ecosystem C balance

Neff, Jason

212

The Economic Potential of Terrestrial Impact Craters  

Microsoft Academic Search

Like concentrations of economic resources, terrestrial impact structures are the result of relatively rare geologic events. Economic resources occur in a number of terrestrial impact structures. After providing a context by briefly summarizing the salient points of the terrestrial impact record and the characteristics of impact craters, the relationship between impact craters and economic resources is explored. Approximately 25% of

R. A. F. Grieve; V. L. Masaitis

1994-01-01

213

Graviton Cosmology in Universal Extra Dimensions  

E-print Network

In models of universal extra dimensions, gravity and all standard model fields propagate in the extra dimensions. Previous studies of such models have concentrated on the Kaluza-Klein (KK) partners of standard model particles. Here we determine the properties of the KK gravitons and explore their cosmological implications. We find the lifetimes of decays to KK gravitons, of relevance for the viability of KK gravitons as dark matter. We then discuss the primordial production of KK gravitons after reheating. The existence of a tower of KK graviton states makes such production extremely efficient: for reheat temperature T_RH and d extra dimensions, the energy density stored in gravitons scales as T_RH^{2+3d/2}. Overclosure and Big Bang nucleosynthesis therefore stringently constrain T_RH in all universal extra dimension scenarios. At the same time, there is a window of reheat temperatures low enough to avoid these constraints and high enough to generate the desired thermal relic density for KK WIMP and superWIMP dark matter.

Jonathan L. Feng; Arvind Rajaraman; Fumihiro Takayama

2003-07-31

214

Alternating extra medullary plasmacytoma of maxilla.  

PubMed

Plasmatytomas of maxilla are rare lesions. Alternating plasmacytoma of maxilla is still rare. A case of maxillary extra medullary plasmacytoma is reported in a patient, who presented with same lesion in the opposite maxillary sinus within one year of initial presentation. On review of available literature we could not find bilateral medullary plasmacytoma involving both maxilla one after another. PMID:23120048

Minhas, R S; Mohindroo, N K; Mohan, C; Sarma, M L

2004-04-01

215

Black hole evaporation and compact extra dimensions  

Microsoft Academic Search

We study the evaporation of black holes in space-times with extra dimensions of size L by employing the microcanonical picture of Hawking's radiation. We show that the luminosity is greatly damped when the horizon becomes smaller than L and black holes born with an initial size smaller than L are almost stable. This effect is due to the strong dependence

Roberto Casadio; Benjamin Harms

2001-01-01

216

Black hole evaporation and large extra dimensions  

Microsoft Academic Search

We study the evaporation of black holes in space-times with extra dimensions of size L. We first obtain a potential which describes the expected behaviors of very large and very small black holes and then show that a (first order) phase transition, possibly signaled by an outburst of energy, occurs in the system when the horizon shrinks below L from

Roberto Casadio; Benjamin Harms

2000-01-01

217

The Delta4 extra performance architecture (XPA)  

Microsoft Academic Search

The design of an extra performance architecture for Delta-4, which explicitly supports the requirements of real-time systems with respect to throughput and response, is presented. The Delta-4 approach to fault tolerance is based on the replication of software components on distinct host computers using a range of different replication strategies. The problems of replicate divergence are discussed, and a solution

P. A. Barret; A. M. Hilborne; P. G. Bond; D. T. Seaton; P. Verissimo; L. Rodrigues; N. A. Speirs

1990-01-01

218

The formation of terrestrial planets  

NASA Astrophysics Data System (ADS)

Previous numerical simulations of the process of formation of the terrestrial planets led to results which typically have two problems: (i) the final orbits of the planets are too eccentric and inclined relative to the real orbits of the terrestrial planet system and (ii) the planets form too slowly with respect to the time indicated by the Hf-W chronometer for the Earth-Moon system. It is usually thought that these problems are due to the fact that the simulations do not account for a population of small planetesimals carrying cumulatively a mass comparable to the mass of the planetary embryos. We have done new simulations, starting with a system of 25 Mars-mass embryos initially distributed from 0.5 to 4 AU, embedded in a disk of 2.5 Earth masses of planetesimals, modeled with 1,000 individual equal-mass particles. We have performed 8 simulations. 4 simulations assumed Jupiter and Saturn initially on their current orbits, while the remaining 4 simulations assumed that the two giant planets had circular orbits, consistent with the `Nice model' on the origin of the late heavy bombardment (Gomes et al., 2005) and on the giant planets' orbital architecture (Tsiganis et al., 2005). The simulations starting with Jupiter on an eccentric orbit lead to the formation of a system of terrestrial planets whose angular momentum deficit is 7 times smaller than that obtained in previous simulations (Chambers, 2001), whereas the formation timescale is three times shorter. This confirms that the dynamical friction exerted by planetesimals onto the forming planets is an essential ingredient in terrestrial planet formation. Interestingly, the final terrestrial planets achieved in these simulations are dynamically colder than the real terrestrial planets. The simulations starting with Jupiter on a circular orbit still produce planets which are slightly too dynamically excited (by about 50%) and which form too slowly (by a factor of 2). These problems are expected to disappear in future simulations modeling the planetesimal disk with a larger number of particles, or accounting for the regeneration of planetesimals during giant collisions among embryos. A main difference between the planets formed in the eccentric Jupiter case with respect to the circular Jupiter case is that the former do not acquire a significant amount of mass from beyond 2.5 AU. These planets are therefore expected to be more deficient in water, possibly too dry with respect to the Earth.

Morbidelli, A.; O'Brien, D.

219

Global Climate Models of the Terrestrial Planets  

NASA Astrophysics Data System (ADS)

On the basis of the global climate models (GCMs) originally developed for Earth, several teams around the world have been able to develop GCMs for the atmospheres of the other terrestrial bodies in our solar system: Venus, Mars, Titan, Triton, and Pluto. In spite of the apparent complexity of climate systems and meteorology, GCMs are based on a limited number of equations. In practice, relatively complete climate simulators can be developed by combining a few components such as a dynamical core, a radiative transfer solver, a parameterization of turbulence and convection, a thermal ground model, and a volatile phase change code, possibly completed by a few specific schemes. It can be shown that many of these GCM components are "universal" so that we can envisage building realistic climate models for any kind of terrestrial planets and atmospheres that we can imagine. Such a tool is useful for conducting scientific investigations on the possible climates of terrestrial extrasolar planets, or to study past environments in the solar system. The ambition behind the development of GCMs is high: The ultimate goal is to build numerical simulators based only on universal physical or chemical equations, yet able to reproduce or predict all the available observations on a given planet, without any ad hoc forcing. In other words, we aim to virtually create in our computers planets that "behave" exactly like the actual planets themselves. In reality, of course, nature is always more complex than expected, but we learn a lot in the process. In this chapter we detail some lessons learned in the solar system: In many cases, GCMs work. They have been able to simulate many aspects of planetary climates without difficulty. In some cases, however, problems have been encountered, sometimes simply because a key process has been forgotten in the model or is not yet correctly parameterized, but also because sometimes the climate regime seems to be result of a subtle balance between processes that remain highly model sensitive, or are the subject of positive feedback and unstability. In any case, building virtual planets with GCMs, in light of the observations obtained by spacecraft or from Earth, is a true scientific endeavor that can teach us a lot about the complex nature of climate systems.

Forget, F.; Lebonnois, S.

220

A comparative analysis of dispersal syndromes in terrestrial and semi-terrestrial animals.  

PubMed

Dispersal, the behaviour ensuring gene flow, tends to covary with a number of morphological, ecological and behavioural traits. While species-specific dispersal behaviours are the product of each species' unique evolutionary history, there may be distinct interspecific patterns of covariation between dispersal and other traits ('dispersal syndromes') due to their shared evolutionary history or shared environments. Using dispersal, phylogeny and trait data for 15 terrestrial and semi-terrestrial animal Orders (> 700 species), we tested for the existence and consistency of dispersal syndromes across species. At this taxonomic scale, dispersal increased linearly with body size in omnivores, but decreased above a critical length in herbivores and carnivores. Species life history and ecology significantly influenced patterns of covariation, with higher phylogenetic signal of dispersal in aerial dispersers compared with ground dwellers and stronger evidence for dispersal syndromes in aerial dispersers and ectotherms, compared with ground dwellers and endotherms. Our results highlight the complex role of dispersal in the evolution of species life-history strategies: good dispersal ability was consistently associated with high fecundity and survival, and in aerial dispersers it was associated with early maturation. We discuss the consequences of these findings for species evolution and range shifts in response to future climate change. PMID:24915998

Stevens, Virginie M; Whitmee, Sarah; Le Galliard, Jean-François; Clobert, Jean; Böhning-Gaese, Katrin; Bonte, Dries; Brändle, Martin; Matthias Dehling, D; Hof, Christian; Trochet, Audrey; Baguette, Michel

2014-08-01

221

Alien Terrestrial Invertebrates of Europe  

Microsoft Academic Search

Unlike other groups of animals and plants, no checklist of alien terrestrial invertebrates was available in any of the European\\u000a countries until recently. Since 2002, such checklists were successively provided by Austria (Essl and Rabitsch 2002), Germany\\u000a (Geiter et al. 2002), the Czech Republic (Šefrová and Lašt? vka 2005), Scandinavia (NOBANIS 2007), the United Kingdom (Hill\\u000a et al. 2005), Switzerland

Alain Roques; Wolfgang Rabitsch; Jean-Yves Rasplus; Carlos Lopez-Vaamonde; Wolfgang Nentwig; Marc Kenis

222

NASA's Terrestrial Planet Finder Missions  

NASA Technical Reports Server (NTRS)

NASA has decided to move forward with two complementary Terrestrial Planet Finder (TPF) missions, a visible coronagraph and an infrared formation flying interferometer. These missions are major missions in the NASA Office of Space Science Origins Theme. The primary science objectives of the TPF missions are to search for, detect, and characterize planets and planetary systems beyond our own Solar System, including specifically Earth-like planets.

Coulter, Daniel R.

2004-01-01

223

The Role of Giant Planets in Terrestrial Planet Formation  

NASA Astrophysics Data System (ADS)

The dynamical structure of the outer planetary system has played a critical role in determining the sizes, numbers, and habitability of the terrestrial planets. In 1996, Wetherill showed that the presence of Jupiter affects the masses of planets in the Habitable Zone of the Sun. In addition, in our solar system the giant planets control the dynamics of most of Earth's impactors, which consist of objects from the asteroid belt, the Kuiper belt, the scattered comet disk, and the Oort cloud. At early times, these impactors may have been responsible for supplying the Earth with a significant fraction of its water, organics, and atmospheric volatiles. At later times, they are responsible for causing at least some mass extinctions. Recent observations have demonstrated that giant planet configurations can show startling variations from system to system. (Although the searches for extra-solar planets have yet to reveal anything about what `typical systems' are like due to strong observational biases.) The question therefore naturally arises: What kind of outer planetary systems can support habitable terrestrial planets? The Exobiology Program is funding us to undertake the first comprehensive study of the coupling between outer solar system architectures and inner solar system habitability. The first stage of this program was to construct a wide range of outer planetary systems. The results of this work can be found at www.boulder.swri.edu/ hal/diversity.html. Here we present a preliminary report on simulations of the formation of terrestrial planets in two of these synthetic outer planetary systems. The first contains 5 planets; three of which lie between 3.7 and 11AU and have a combined mass of 2600 Earth-masses ( 8 Jupiter-masses). The second system contains 7 planets between 4 and 35AU; the largest of which is only 26 Earth-masses ( 1.5 Neptune masses).

Levison, H. F.; Duncan, M. J.; Agnor, C. B.

2000-05-01

224

Arsenic Speciation of Terrestrial Invertebrates  

SciTech Connect

The distribution and chemical form (speciation) of arsenic in terrestrial food chains determines both the amount of arsenic available to higher organisms, and the toxicity of this metalloid in affected ecosystems. Invertebrates are part of complex terrestrial food webs. This paper provides arsenic concentrations and arsenic speciation profiles for eight orders of terrestrial invertebrates collected at three historical gold mine sites and one background site in Nova Scotia, Canada. Total arsenic concentrations, determined by inductively coupled plasma mass spectrometry (ICP-MS), were dependent upon the classification of invertebrate. Arsenic species were determined by high-performance liquid chromatography (HPLC) ICP-MS and X-ray absorption spectroscopy (XAS). Invertebrates were found by HPLC ICP-MS to contain predominantly arsenite and arsenate in methanol/water extracts, while XAS revealed that most arsenic is bound to sulfur in vivo. Examination of the spatial distribution of arsenic within an ant tissue highlighted the differences between exogenous and endogenous arsenic, as well as the extent to which arsenic is transformed upon ingestion. Similar arsenic speciation patterns for invertebrate groups were observed across sites. Trace amounts of arsenobetaine and arsenocholine were identified in slugs, ants, and spiders.

Moriarty, M.M.; Koch, I.; Gordon, R.A.; Reimer, K.J. ((Simon)); ((Royal))

2009-07-01

225

Natural organobromine in terrestrial ecosystems  

NASA Astrophysics Data System (ADS)

Recent studies have shown that bromine undergoes biogeochemical cycling involving natural formation and degradation of organobromine compounds in marine systems. In the terrestrial environment, where background bromine levels tend to be low, the biogeochemistry of this element remains largely unexamined. We traced the path of bromine through plant growth, senescence, and decay of leaf litter on the forest floor. Using sensitive X-ray spectroscopic techniques, we show that all bromine in humified plant material, organic-rich surface soils, and isolated humic substances is bonded to carbon. Analysis of bromide-enriched plants suggests that bromide absorbed by the growing plants ultimately converts to organobromine when the plant litter decays. Application of isolated chloroperoxidase, a halogenating enzyme, to healthy plant material results in extensive bromination, with organobromine formed preferentially over organochlorine. The relative ease of bromide oxidation appears to promote biogeochemical transformations of Br from inorganic to organic forms, leading to its incorporation into soil organic matter through enzymatic processes related to plant litter decomposition. In combination with low concentration and susceptibility to leaching and plant uptake, natural bromination processes lead to the exhaustion of inorganic bromide in surface soils, making organic matter a reservoir of bromine in the terrestrial environment. This study provides the first detailed look into the terrestrial bromine cycle and lays the foundation for future studies of natural organobromine degradation, which may shed light on the fate of anthropogenic organobromine pollutants in the soil environment.

Leri, Alessandra C.; Myneni, Satish C. B.

2012-01-01

226

Arsenic speciation of terrestrial invertebrates.  

PubMed

The distribution and chemical form (speciation) of arsenic in terrestrial food chains determines both the amount of arsenic available to higher organisms, and the toxicity of this metalloid in affected ecosystems. Invertebrates are part of complex terrestrial food webs. This paper provides arsenic concentrations and arsenic speciation profiles for eight orders of terrestrial invertebrates collected at three historical gold mine sites and one background site in Nova Scotia, Canada. Total arsenic concentrations, determined by inductively coupled plasma mass spectrometry (ICP-MS), were dependent upon the classification of invertebrate. Arsenic species were determined by high-performance liquid chromatography (HPLC) ICP-MS and X-ray absorption spectroscopy (XAS). Invertebrates were found by HPLC ICP-MS to contain predominantly arsenite and arsenate in methanol/water extracts, while XAS revealed that most arsenic is bound to sulfur in vivo. Examination of the spatial distribution of arsenic within an ant tissue highlighted the differences between exogenous and endogenous arsenic, as well as the extent to which arsenic is transformed upon ingestion. Similar arsenic speciation patterns for invertebrate groups were observed across sites. Trace amounts of arsenobetaine and arsenocholine were identified in slugs, ants, and spiders. PMID:19673270

Moriarty, Maeve M; Koch, Iris; Gordon, Robert A; Reimer, Kenneth J

2009-07-01

227

Reduction and identification for hybrid dynamical models of terrestrial locomotion  

NASA Astrophysics Data System (ADS)

The study of terrestrial locomotion has compelling applications ranging from design of legged robots to development of novel prosthetic devices. From a first-principles perspective, the dynamics of legged locomotion seem overwhelmingly complex as nonlinear rigid body dynamics couple to a granular substrate through viscoelastic limbs. However, a surfeit of empirical data demonstrates that animals use a small fraction of their available degrees-of-freedom during locomotion on regular terrain, suggesting that a reduced-order model can accurately describe the dynamical variation observed during steady-state locomotion. Exploiting this emergent phenomena has the potential to dramatically simplify design and control of micro-scale legged robots. We propose a paradigm for studying dynamic terrestrial locomotion using empirically-validated reduced{order models.

Burden, Samuel A.; Sastry, S. Shankar

2013-06-01

228

FORMATION OF THE TERRESTRIAL PLANETS FROM A NARROW ANNULUS  

SciTech Connect

We show that the assembly of the solar system terrestrial planets can be successfully modeled with all of the mass initially confined to a narrow annulus between 0.7 and 1.0 AU. With this configuration, analogs of Mercury and Mars often form from the collisional evolution of material diffusing out of the annulus under the scattering of the forming Earth and Venus analogs. The final systems also possess eccentricities and inclinations that match the observations, without recourse to dynamical friction from remnant small body populations. Finally, the characteristic assembly timescale for Earth analogs is rapid in this model and consistent with cosmochemical models based on the {sup 182}Hf-{sup 182}W isotopes. The agreement between this model and the observations suggests that terrestrial planet systems may also be formed in 'planet traps', as has been proposed recently for the cores of giant planets in our solar system and others.

Hansen, Brad M. S., E-mail: hansen@astro.ucla.ed [Department of Physics and Astronomy, and Institute of Geophysics and Planetary Physics, University of California Los Angeles, Los Angeles, CA 90095 (United States)

2009-09-20

229

The dynamical stability of extra-solar planets in binary systems  

Microsoft Academic Search

The question about dynamical stability of extra-solar planets is considered in the frame of the general three-body problem, i.e. a planet in the binary system revolves around one of the components. The distance between the star's components is much longer than between the orbiting star and the planet. In the differential equations with regard to the eccentricity and the argument

N. A. Solovaya; E. M. Pittich

2004-01-01

230

Effects of Type I Migration on Terrestrial Planet Formation  

E-print Network

Planetary embryos embedded in a gas disc suffer a decay in semimajor axis -- type I migration -- due to the asymmetric torques produced by the interior and exterior wakes raised by the body (Goldreich & Tremaine 1980; Ward 1986). This presents a challenge for standard oligarchic approaches to forming the terrestrial planets (Kokubo & Ida 1998) as the timescale to grow the progenitor objects near 1 AU is longer than that for them to decay into the Sun. In this paper we investigate the middle and late stages of oligarchic growth using both semi-analytic methods (based upon Thommes et al. 2003) and N-body integrations, and vary gas properties such as dissipation timescale in different models of the protoplanetary disc. We conclude that even for near-nominal migration efficiencies and gas dissipation timescales of ~1 Myr it is possible to maintain sufficient mass in the terrestrial region to form Earth and Venus if the disc mass is enhanced by factors of ~2-4 over the minimum mass model. The resulting configurations differ in several ways from the initial conditions used in previous simulations of the final stages of terrestrial accretion (e.g. Chambers 2001), chiefly in (1) larger inter-embryo spacings, (2) larger embryo masses, and (3) up to ~0.4 Earth masses of material left in the form of planetesimals when the gas vanishes. The systems we produce are reasonably stable for ~100 Myr and therefore require an external source to stir up the embryos sufficiently to produce final systems resembling the terrestrial planets.

D. S. McNeil; M. J. Duncan; H. F. Levison

2005-10-10

231

Extra-hepatic metabolism of midazolam.  

PubMed Central

Six patients received 10 mg of midazolam intravenously during the anhepatic period of liver transplantation. Arterial blood was sampled during this time and for a similar period following revascularisation. The plasma was analysed using gas chromatography and electron capture detection (GC-ECD) for midazolam alpha-hydroxymidazolam and alpha-hydroxymidazolam glucuronide. Five of the six patients had small but significant concentrations of metabolites detected during the anhepatic period, demonstrating the presence of extra-hepatic sites of metabolism for this drug. The remaining patient had plasma concentrations of metabolites below the lower limit of detection (2 micrograms l-1). This may represent a pharmacogenetic abnormality or a temporary failure of midazolam metabolism secondary to the patients illness affecting the extra-hepatic sites of metabolism. PMID:2667600

Park, G R; Manara, A R; Dawling, S

1989-01-01

232

Extra dimensions, orthopositronium decay, and stellar cooling  

E-print Network

In a class of extra dimensional models with a warped metric and a single brane the photon can be localized on the brane by gravity only. An intriguing feature of these models is the possibility of the photon escaping into the extra dimensions. The search for this effect has motivated the present round of precision orthopositronium decay experiments. We point out that in this framework a photon in plasma should be metastable. We consider the astrophysical consequences of this observation, in particular, what it implies for the plasmon decay rate in globular cluster stars and for the core-collapse supernova cooling rate. The resulting bounds on the model parameter exceed the possible reach of orthopositronium experiments by many orders of magnitude.

Alexander Friedland; Maurizio Giannotti

2007-09-14

233

Stellar evolution and large extra dimensions  

E-print Network

We discuss in detail the information on large extra dimensions which can be derived in the framework of stellar evolution theory and observation. The main effect of large extra dimensions arises from the production of the Kaluza-Klein (KK) excitations of the graviton. The KK-graviton and matter interactions are of gravitational strength, so the KK states never become thermalized and always freely escape. In this paper we first pay attention to the sun. Production of KK gravitons is incompatible with helioseismic constraints unless the 4+n dimensional Planck mass M_s exceeds 300 Gev/c^2. Next we show that stellar structures in their advanced phase of H burning evolution put much more severe constraints, M_s > 3-4 TeV/c^2, improving on current laboratory lower limits.

S. Cassisi; V. Castellani; S. Degl'Innocenti G. Fiorentini; B. Ricci

2000-02-08

234

Who Does Extra-Credit Work in Introductory Science Courses?  

ERIC Educational Resources Information Center

On the first day of classes, 81% of students in an introductory biology course claimed that they would submit extra-credit work if given the opportunity. When given two chances for extra-credit work, fewer than one-fourth of students submitted one or both assignments. Students who submitted extra-credit work were more likely to attend class,…

Moore, Randy

2005-01-01

235

The distal forelimb musculature in aquatic and terrestrial turtles: phylogeny or environmental constraints?  

PubMed Central

We compared the muscular anatomy of the distal front limb in terrestrial and aquatic chelonians to test whether observed differences between the two groups are associated with their divergent lifestyles and locomotor modes. Given the different use of the forelimb in the two environments (body support and propulsion on land vs. mainly propulsion in water) we expected that: (1) aquatic and terrestrial turtles would show differences in their muscular anatomy, with aquatic species having more individualized muscle bundles to allow for the complex forearm movements observed during swimming, and (2) that terrestrial turtles would have more robust muscles to support their body weight against gravity. To address these questions, we examined the forelimb myology and associated tissues in six aquatic or semi-aquatic turtles (Phyrnops hilarii, Podocnemis unifilis, Trachemys scripta, Sacalia bealei, Cuora amboinensis and Mauremys caspica) and six terrestrial or semi-terrestrial turtles (Geochelone chilensis, Testudo graeca, Cuora galbinifrons, Glyptemys insculpta, Terrapene carolina and Rhinoclemmys pulcherrima). This paper describes the general structure of the forelimb musculature in all species, and quantifies muscle masses in those species with more than five specimens available (Ph. hilarii, Po. unifilis and Ge. chilensis). The general structure of the forelimb muscles in the strictly terrestrial species Ge. chilensis and Tes. graeca was found to be notably different from the pattern of the aquatic and semi-aquatic species examined, showing a distinct fusion of the different muscular bodies. Ter. carolina also show a distinctly terrestrial pattern, but a less extensive tendon development. R. pulcherrima and Gl. insculpta were found to be morphologically intermediate; in the geoemydids the strictly terrestrial bauplan never appears. Quantitative differences in the robustness or mass of the distal forelimb muscles were also observed for the species investigated, supporting our prediction that the extensor muscles are more robust in terrestrial turtles. However, in contrast to our expectations, not only the extensor muscles of the distal forelimb (which are crucial in providing both body support and propulsion), but all muscles acting around the wrist were found to be heavier in terrestrial turtles. PMID:19172731

Abdala, Virginia; Manzano, Adriana S; Herrel, Anthony

2008-01-01

236

Extra gauge symmetries in BHT gravity  

E-print Network

We study the canonical structure of the Bergshoeff-Hohm-Townsend massive gravity, linearized around a maximally symmetric background. At the critical point in the space of parameters, defined by $\\Lambda_0/m^2=-1$, we discover an extra gauge symmetry, which reflects the existence of the partially massless mode. The number of the Lagrangian degrees of freedom is found to be 1. We show that the canonical structure of the theory at the critical point is unstable under linearization.

M. Blagojevi?; B. Cvetkovi?

2011-04-04

237

Extra gauge symmetries in BHT gravity  

NASA Astrophysics Data System (ADS)

We study the canonical structure of the Bergshoeff-Hohm-Townsend massive gravity, linearized around a maximally symmetric background. At the critical point in the space of parameters, defined by ? 0/ m 2 = -1, we discover an extra gauge symmetry, which reflects the existence of the partially massless mode. The number of the Lagrangian degrees of freedom is found to be 1. We show that the canonical structure of the theory at the critical point is unstable under linearization.

Blagojevi?, M.; Cvetkovi?, B.

2011-03-01

238

Extra gauge symmetries in BHT gravity  

E-print Network

We study the canonical structure of the Bergshoeff-Hohm-Townsend massive gravity, linearized around a maximally symmetric background. At the critical point in the space of parameters, defined by $\\Lambda_0/m^2=-1$, we discover an extra gauge symmetry, which reflects the existence of the partially massless mode. The number of the Lagrangian degrees of freedom is found to be 1. We show that the canonical structure of the theory at the critical point is unstable under linearization.

Blagojevi?, M

2011-01-01

239

Kinks, extra dimensions, and gravitational waves  

SciTech Connect

We investigate in detail the gravitational wave signal from kinks on cosmic (super)strings, including the kinematical effects from the internal extra dimensions. We find that the signal is suppressed, however, the effect is less significant that that for cusps. Combined with the greater incidence of kinks on (super)strings, it is likely that the kink signal offers the better chance for detection of cosmic (super)strings.

O'Callaghan, Eimear; Gregory, Ruth, E-mail: r.a.w.gregory@durham.ac.uk [Institute for Particle Physics Phenomenology and Centre for Particle Theory, Durham University, South Road, Durham, DH1 3LE (United Kingdom)

2011-03-01

240

Metastable gravitons and infinite volume extra dimensions  

Microsoft Academic Search

We address the issue of whether extra dimensions could have an infinite volume and yet reproduce the effects of observable four-dimensional gravity on a brane. There is no normalizable zero-mode graviton in this case, nevertheless correct Newton's law can be obtained by exchanging bulk gravitons. This can be interpreted as an exchange of a single metastable 4D graviton. Such theories

G. Dvali; G. Gabadadze; M. Porrati

2000-01-01

241

Extra-corporeal shock wave lithotripsy.  

PubMed Central

Extra-corporeal shock wave lithotripsy (ESWL) has proved to be a revolutionary advance in the treatment of renal stone disease. It, itself, is non-invasive but may necessitate or be used as an adjunct to more invasive auxiliary procedures. The basic principles of lithotripsy, the clinical experience thus far and probable future applications are discussed. Images Figure 2 Figure 4 Figure 5 Figure 7 Figure 8 PMID:3330235

Pemberton, J.

1987-01-01

242

Dimensional reduction without continuous extra dimensions  

SciTech Connect

We describe a novel approach to dimensional reduction in classical field theory. Inspired by ideas from noncommutative geometry, we introduce extended algebras of differential forms over space-time, generalized exterior derivatives, and generalized connections associated with the 'geometry' of space-times with discrete extra dimensions. We apply our formalism to theories of gauge- and gravitational fields and find natural geometrical origins for an axion- and a dilaton field, as well as a Higgs field.

Chamseddine, Ali H. [American University of Beirut, Physics Department, Beirut, Lebanon and I.H.E.S. F-91440 Bures-sur-Yvette (France)] [American University of Beirut, Physics Department, Beirut, Lebanon and I.H.E.S. F-91440 Bures-sur-Yvette (France); Froehlich, J.; Schubnel, B. [ETHZ, Mathematics and Physics Departments, Zuerich (Switzerland)] [ETHZ, Mathematics and Physics Departments, Zuerich (Switzerland); Wyler, D. [Institute of Theoretical Physics, University of Zuerich (Switzerland)] [Institute of Theoretical Physics, University of Zuerich (Switzerland)

2013-01-15

243

Extra Large Temporal Tunnel Cataract Extraction [ETCE  

PubMed Central

Purpose: To determine the outcomes of extra large temporal sclero-corneal tunnel incision Cataract Surgery. Materials and Methods: This consecutive case series of eyes undergoing temporal tunnel cataract extraction with tunnel length of 8 to 10 mm was identified retrospectively. Surgical procedure details, follow up, complications, visual and astigmatic outcomes at 6wks were recorded and analysed. Results: Ninety six eyes with extra large tunnel incision were identified for analysis from a dataset of 670 manual small incision cataract surgery cases. 58% eyes had NO5 or denser cataracts. Intraoperative complications included, tunnel related problems (1 eye, 1.04%), bleeding into Anterior Chamber (10 eyes, 10.4%), Posterior Capsular Rent (2 eyes, 2.1%). Early postoperative complications included striate keratopathy (7 eyes, 7.3%). The mean Best Corrected Visual Acuity was 6/7.5 (0.1 logMAR) and 98% cases had Best Corrected Visual Acuity of 6/12 (0.3 logMAR) or better at 6wk. The aggregate Surgically Induced Astigmatism was 0.32D at 850. Conclusion: Extra Large Tunnel of length 8 to 10 mm can be self sealing with low SIA. The complication rates and visual outcomes of ETCE are comparable to those of conventional MSICS. This method can be valuable in complicated cases and during learning period. PMID:25386505

U., Vivekanand

2014-01-01

244

Noncommutative Inspired Black Holes in Extra Dimensions  

SciTech Connect

In a recent string theory motivated paper, Nicolini, Smailagic and Spallucci (NSS) presented an interesting model for a noncommutative inspired, Schwarzschild-like black hole solution in 4-dimensions. The essential effect of having noncommutative co-ordinates in this approach is to smear out matter distributions on a scale associated with the turn-on of noncommutativity which was taken to be near the 4-d Planck mass. In particular, NSS assumed that this smearing was essentially Gaussian. This energy scale is sufficiently large that in 4-d such effects may remain invisible indefinitely. Extra dimensional models which attempt to address the gauge hierarchy problem, however, allow for the possibility that the effective fundamental scale may not be far from {approx} 1 TeV, an energy regime that will soon be probed by experiments at both the LHC and ILC. In this paper we generalize the NSS model to the case where flat, toroidally compactified extra dimensions are accessible at the TeV-scale and examine the resulting modifications in black hole properties due to the existence of noncommutativity. We show that while many of the noncommutativity-induced black hole features found in 4-d by NSS persist, in some cases there can be significant modifications due the presence of extra dimensions. We also demonstrate that the essential features of this approach are not particularly sensitive to the Gaussian nature of the smearing assumed by NSS.

Rizzo, Thomas G.

2006-06-07

245

Standard Model scales from warped extra dimensions  

E-print Network

If in the Randall and Sundrum RS1 model the inverse of the compactification radius, the AdS curvature scale, and the five and four-dimensional Planck scales are equal in size, as is natural, then the warp factor at the location of the low energy brane is of value 1/pi. So that all scales derive from locations in the space, we identify the extra dimension with the infinite covering space of the S1/Z2 orbifold. The extra dimension is then essentially a series of connected line intervals, punctuated by branes. Scales on successive branes in the extra dimension descend from Planck scale in a geometric sequence of common ratio 1/pi. Evidence is provided for such a sequence within the spectrum of particle masses, and of a second geometric sequence, of common ratio 2/pi, which suggests that the AdS spacetime is six-dimensional and doubly warped. The scales of the Standard Model lie at coincident levels within the two sequences. A third sequence, of common ratio 1/e, provides a symmetrical framework for the Standard Model and points to a warped product spacetime.

Bernard Riley

2008-08-31

246

Moon and Terrestrial Planets: Unresolved Questions  

NASA Astrophysics Data System (ADS)

Human exploration during Apollo began the documentation of the evolution of the Moon and of its importance in understanding the origin and evolution of the terrestrial planets. This revolution in planetary geology continues as a vigorous and vibrant arena for discovery and debate for new generations of geoscientists. Although much has been learned and, indeed, resolved in lunar science, we are left with major questions unresolved. One fundamental question is that of the origin of the Moon. A large consensus has developed in the planetary science community that the Moon was created by the "giant impact" of a Mars-sized asteroid on the Earth after the accretion of the Earth was largely complete and differentiation had begun. A minority, however, questions this consensus hypothesis because of increasing indications that the lower mantle of the Moon may be largely undifferentiated. If the issue of the high angular momentum of the Earth-Moon system can be resolved through new modeling studies, then capture of a co-orbiting planetesimal may be an important alternative to a "giant impact". Another important question, particularly in consideration of the terrestrial and Martian surface environments during the first 0.8 billion years of Earth history, is the impact record of that period as recorded on the Moon. Again, a large consensus has developed that the 50 or so large and very large impact basins identified on the Moon were created over a very short "cataclysm" between about 3.9 and 3.8 billion years ago. Here also, a minority suggests that this period of large basin formation, although distinct in lunar history, took place over several hundred million years and that the apparent cataclysm is an artifact of sampling the effects of the last few basin-forming impacts. Either way, a previously unavailable source of impactors appeared somewhere in the solar system and greatly affected terrestrial environments at the time the precursors to life were appearing on Earth. Additional unresolved questions raised by lunar exploration and study include 1) the effect of chondritic proto-cores on the timing of core formation in the terrestrial planets, 2) the number of extremely large basin-forming events (lunar diameters >2000 km) and the potential for proto-continents being formed by the differentiation of their melt sheets on water-rich planets, 3) effect of clays produced by the weathering of the debris and glass produced by pervasive asteroid and cometary impacts, 4) the many details of the differentiation of magma oceans, and 5) the processes governing the evolution of the lunar regolith. Finally, there is the question of when humans shall return to the Moon. On the one hand, the use of this unique and accessible planetary body as a scientific resource has barely begun. On the other hand, the Helium-3 fusion energy resources and deep space travel consumables that remain untapped in the lunar regolith hardly can be ignored in the face of human and environmental challenges on Earth and the species' desire to go to Mars. On both hands, it is time we took another walk on the Moon. 30 years going on 40 is long enough to think about what once was possible.

Schmitt, H. H.

2002-12-01

247

About Tagish Lake as a Potential Parent Body for Polar Micrometeorites; Clues from their Hydrogen Isotopic Compositions  

NASA Technical Reports Server (NTRS)

The origin of the Antarctic micrometeorites (AMMs) is still a matter of debate. Their closest meteoritic counterparts are the C2 chondrites, but the match is not perfect, and the parent body(ies) of the AMMs is(are) still to be identified. Tagish Lake is a new meteorite fall which bears similarity with CI1 and CM2 chondrites, but is distinct from both. Based on the mineralogy of phyllosilicates, Noguchi et al. proposed that the phyllosilicate-rich AMMs and the Tagish Lake meteorites could derive from similar asteroids. The hydrogen isotopic compositions of extra-terrestrial samples can be used to get some insight on their origin. The D/H ratios of AMMs and of Tagish Lake have been measured, but using different analytical techniques. They are therefore not directly comparable. We performed additional hydrogen isotopic analyses of fragments of Tagish Lake using the same experimental setup previously used for the measurement of the hydrogen isotopic composition of AMMs. In this work, we could also analyze separately both lithologies of Tagish Lake (carbonate-poor and -rich). The distributions of delta D values measured in the two lithologies of Tagish Lake are very similar, indicating that fluids with similar hydrogen isotopic compositions altered the meteorite on the parent body for the two lithologies. Yet, the hydrogen isotopic composition of Tagish Lake is different from that of AMMs, suggesting that they do not derive from the same parent body.

Engrand, C.; Gounelle, M.; Zolensky, M. E.; Duprat, J.

2003-01-01

248

Irreversible evolution of the terrestrial planets (geological and petrological data)  

NASA Astrophysics Data System (ADS)

Abstract Comparative studying of tectonomagmatic evolution of the Earth and the Moon shows that cardinal irreversible change in character of tectonomagmatic processes occurred at middle stages of their evolution; very likely such changes took place on other terrestrial planets (Venus, Mars and Mercury). As a result, primordial crusts of the planets were in considerable degree replaced by secondary basaltic ones. The established succession of events on the Earth could be provided by a combination of two independent factors: (1) it was originally heterogeneous and 2) its downward heating was followed by the cooling of its outer shells. As a result the primary iron core material was long time remained untouched and was involved into global tectonomagmatic processes at ca. 2.4-2.3 Ga. We concluded about a similar scenario for the evolution of Moon and other terrestrial planets. Tectonomagmatic evolution of the terrestrial planets (Earth, Venus, Mars, Mercury and Moon) was studied. What did major stages of their irreversible evolution occur before they turned into "dead" stone balls? We discuss these problems on examples of the Earth and the Moon, which evolution studied the best. According to modern views, after accretion of these bodies, magma oceans of some hundreds km deep appeared on their surface. According to Jeffries [1], solidification of large molted bodies, because of the difference between adiabatic gradient in silicate melts (0.3oC/km) and gradient of their melting points (3oC/km), could be going only upwards, from the bottom to the surface. As a result a powerful crystallizing differentiation of the oceans' magmas occurred with accumulation of the most low-melting components to the surface. Due to different deep of the magma oceans on the Earth and the Moon, the primordial crusts on these bodies were rather different: sialic on the Earth and basic (anorthosite) on the Moon.

Sharkov, E.; Bogatikov, O.

2008-09-01

249

ExtraSolar Planets Finding Extrasolar Planets. I  

E-print Network

systems have been found. No terrestrial planets are yet known (smallest: 7.5M) The COROT and KEPLER missions are designed to find terrestrial planets using transits Hot Jupiters predominate around young in the Galaxy Hot Jupiters may indicate very different systems We can't say much about terrestrial planets yet

Walter, Frederick M.

250

Accumulation of the Terrestrial Planets  

NASA Technical Reports Server (NTRS)

The validity of the two body approximation in calculations of planetary growth is examined. Use of this approximation is essential to practical 3 dimensional simulations of planetary growth. With regard to gravitational perturbations, the changes in semimajor axis, eccentricity, and inclination resulting from close planetesimal encounters (near 1 A.U.) out to 10 Tisserand sphere of influence radii were calculated by two and three dimensional numerical integration. These were compared with the results of treating the encounter as a two body problem, as is customary in Monte Carlo calculations of orbital evolution and in numerical and analytical studies of planetary accumulation. It is found that for values of (V/V sub e) approx. 0.35 (V = relative velocity, V = escape velocity of largest body), the two body approximation fails to describe the outcome of individual encounters. In this low velocity region, the two body gravitational focusing cross section is no longer valid.

Wetherill, G. W.

1985-01-01

251

Variable Extra Dimensional Spacetime and Solution to Initial Singularity Paradox of Our Universe From Extra Dimensions  

E-print Network

Considering a n-dimensional general spacetime, we deduce its 4-dimensional Einstein equation and Friedman equations, and discover a general dual relation between the scale factor $a(t)$ of our universe and the scale factor $B(t)$ of extra dimensions. Based on the dual relation equation, predictions of shrinking of extra dimensions and free of singularity problem of our universe are given. Therefore, solution to initial singularity paradox of our universe is achieved. Because the dual relation is general, this Letter discovers that it is just the extra dimensional shrinking contribution that results in our universe's expanding in terms of the dual relation in the bulk space, and actually the dual relation is deduced doesn't depend on the 4-dimensional matter concrete Lagrangian, these are key important for a lot of future relative investigations.

Yong-Chang Huang; LiuJi Li

2015-01-18

252

Effects of Planetesimal Dynamics on the Formation of Terrestrial Planets  

E-print Network

Formation of terrestrial planets by agglomeration of planetesimals in protoplanetary disks sensitively depends on the velocity evolution of planetesimals. We describe a novel semi-analytical approach to the treatment of planetesimal dynamics incorporating the gravitational scattering by massive protoplanetary bodies. Using this method we confirm that planets grow very slowly in the outer Solar System if gravitational scattering is the only process determining planetesimal velocities, making it hard for giant planets to acquire their massive gaseous envelopes within less than 10 Myr. We put forward several possibilities for alleviating this problem.

Roman R. Rafikov

2003-10-14

253

Cadaver decomposition in terrestrial ecosystems  

NASA Astrophysics Data System (ADS)

A dead mammal (i.e. cadaver) is a high quality resource (narrow carbon:nitrogen ratio, high water content) that releases an intense, localised pulse of carbon and nutrients into the soil upon decomposition. Despite the fact that as much as 5,000 kg of cadaver can be introduced to a square kilometre of terrestrial ecosystem each year, cadaver decomposition remains a neglected microsere. Here we review the processes associated with the introduction of cadaver-derived carbon and nutrients into soil from forensic and ecological settings to show that cadaver decomposition can have a greater, albeit localised, effect on belowground ecology than plant and faecal resources. Cadaveric materials are rapidly introduced to belowground floral and faunal communities, which results in the formation of a highly concentrated island of fertility, or cadaver decomposition island (CDI). CDIs are associated with increased soil microbial biomass, microbial activity (C mineralisation) and nematode abundance. Each CDI is an ephemeral natural disturbance that, in addition to releasing energy and nutrients to the wider ecosystem, acts as a hub by receiving these materials in the form of dead insects, exuvia and puparia, faecal matter (from scavengers, grazers and predators) and feathers (from avian scavengers and predators). As such, CDIs contribute to landscape heterogeneity. Furthermore, CDIs are a specialised habitat for a number of flies, beetles and pioneer vegetation, which enhances biodiversity in terrestrial ecosystems.

Carter, David O.; Yellowlees, David; Tibbett, Mark

2007-01-01

254

Cadaver decomposition in terrestrial ecosystems.  

PubMed

A dead mammal (i.e. cadaver) is a high quality resource (narrow carbon:nitrogen ratio, high water content) that releases an intense, localised pulse of carbon and nutrients into the soil upon decomposition. Despite the fact that as much as 5,000 kg of cadaver can be introduced to a square kilometre of terrestrial ecosystem each year, cadaver decomposition remains a neglected microsere. Here we review the processes associated with the introduction of cadaver-derived carbon and nutrients into soil from forensic and ecological settings to show that cadaver decomposition can have a greater, albeit localised, effect on belowground ecology than plant and faecal resources. Cadaveric materials are rapidly introduced to belowground floral and faunal communities, which results in the formation of a highly concentrated island of fertility, or cadaver decomposition island (CDI). CDIs are associated with increased soil microbial biomass, microbial activity (C mineralisation) and nematode abundance. Each CDI is an ephemeral natural disturbance that, in addition to releasing energy and nutrients to the wider ecosystem, acts as a hub by receiving these materials in the form of dead insects, exuvia and puparia, faecal matter (from scavengers, grazers and predators) and feathers (from avian scavengers and predators). As such, CDIs contribute to landscape heterogeneity. Furthermore, CDIs are a specialised habitat for a number of flies, beetles and pioneer vegetation, which enhances biodiversity in terrestrial ecosystems. PMID:17091303

Carter, David O; Yellowlees, David; Tibbett, Mark

2007-01-01

255

The Laboratory for Terrestrial Physics  

NASA Technical Reports Server (NTRS)

The Laboratory for Terrestrial Physics is dedicated to the advancement of knowledge in Earth and planetary science, by conducting innovative research using space technology. The Laboratory's mission and activities support the work and new initiatives at NASA's Goddard Space Flight Center (GSFC). The Laboratory's success contributes to the Earth Science Directorate as a national resource for studies of Earth from Space. The Laboratory is part of the Earth Science Directorate based at the GSFC in Greenbelt, MD. The Directorate itself is comprised of the Global Change Data Center (GCDC), the Space Data and Computing Division (SDCD), and four science Laboratories, including Laboratory for Terrestrial Physics, Laboratory for Atmospheres, and Laboratory for Hydrospheric Processes all in Greenbelt, MD. The fourth research organization, Goddard Institute for Space Studies (GISS), is in New York, NY. Relevant to NASA's Strategic Plan, the Laboratory ensures that all work undertaken and completed is within the vision of GSFC. The philosophy of the Laboratory is to balance the completion of near term goals, while building on the Laboratory's achievements as a foundation for the scientific challenges in the future.

2003-01-01

256

Dietary characterization of terrestrial mammals.  

PubMed

Understanding the feeding behaviour of the species that make up any ecosystem is essential for designing further research. Mammals have been studied intensively, but the criteria used for classifying their diets are far from being standardized. We built a database summarizing the dietary preferences of terrestrial mammals using published data regarding their stomach contents. We performed multivariate analyses in order to set up a standardized classification scheme. Ideally, food consumption percentages should be used instead of qualitative classifications. However, when highly detailed information is not available we propose classifying animals based on their main feeding resources. They should be classified as generalists when none of the feeding resources constitute over 50% of the diet. The term 'omnivore' should be avoided because it does not communicate all the complexity inherent to food choice. Moreover, the so-called omnivore diets actually involve several distinctive adaptations. Our dataset shows that terrestrial mammals are generally highly specialized and that some degree of food mixing may even be required for most species. PMID:25009067

Pineda-Munoz, Silvia; Alroy, John

2014-08-22

257

Dietary characterization of terrestrial mammals  

PubMed Central

Understanding the feeding behaviour of the species that make up any ecosystem is essential for designing further research. Mammals have been studied intensively, but the criteria used for classifying their diets are far from being standardized. We built a database summarizing the dietary preferences of terrestrial mammals using published data regarding their stomach contents. We performed multivariate analyses in order to set up a standardized classification scheme. Ideally, food consumption percentages should be used instead of qualitative classifications. However, when highly detailed information is not available we propose classifying animals based on their main feeding resources. They should be classified as generalists when none of the feeding resources constitute over 50% of the diet. The term ‘omnivore’ should be avoided because it does not communicate all the complexity inherent to food choice. Moreover, the so-called omnivore diets actually involve several distinctive adaptations. Our dataset shows that terrestrial mammals are generally highly specialized and that some degree of food mixing may even be required for most species. PMID:25009067

Pineda-Munoz, Silvia; Alroy, John

2014-01-01

258

Internal Representation and Memory Formation of Odor Preference Based on Oscillatory Activities in a Terrestrial Slug  

ERIC Educational Resources Information Center

The terrestrial slug "Limax" exhibits a highly developed ability to learn odors with a small nervous system. When a fluorescent dye, Lucifer Yellow (LY), is injected into the slug's body cavity after odor-taste associative conditioning, a group of neurons in the procerebral (PC) lobe, an olfactory center of the slug, is labeled by LY. We examined…

Sekiguchi, Tatsuhiko; Furudate, Hiroyuki; Kimura, Tetsuya

2010-01-01

259

Simple Non-Coriolis Treatments for Explaining Terrestrial East-West Deflections  

ERIC Educational Resources Information Center

Presents two simple methods of calculating the respective terrestrial westward and eastward displacements of a vertically projected and a perpendicularly dropped body which give due emphasis to physical principles, including Kepler's law, conservation of angular momentum, and nonrotating coordinate system with origin at the earth's center. (CC)

Wild, John F.

1973-01-01

260

Lack of Evidence for 3\\/4 Scaling of Metabolism in Terrestrial Plants  

Microsoft Academic Search

Scaling, as the translation of information across spatial, temporal, and organizational scales, is essential to predictions and understanding in all sciences and has become a central issue in ecology. A large body of theoretical and empirical evidence concerning allometric scaling in terrestrial individual plants and plant communities has been constructed around the fractal volume-filling theory of West, Brown, and Enquist

Hai-Tao LI; Xing-Guo HAN; Jian-Guo WU

2005-01-01

261

The Manicouagan impact structure as a terrestrial analogue site for lunar and martian planetary science  

Microsoft Academic Search

The 90 km diameter, late Triassic Manicouagan impact structure of Québec, Canada, is a well-preserved, undeformed complex crater possessing an anorthositic central uplift and a 55 km diameter melt sheet. As such, it provides a valuable terrestrial analogue for impact structures developed on other planetary bodies, especially the Moon and Mars, which are currently the focus of exploration initiatives. The

John G. Spray; Lucy M. Thompson; Marc B. Biren; Catherine O'Connell-Cooper

2010-01-01

262

The Manicouagan impact structure as a terrestrial analogue site for lunar and martian planetary science  

Microsoft Academic Search

The 90km diameter, late Triassic Manicouagan impact structure of Québec, Canada, is a well-preserved, undeformed complex crater possessing an anorthositic central uplift and a 55km diameter melt sheet. As such, it provides a valuable terrestrial analogue for impact structures developed on other planetary bodies, especially the Moon and Mars, which are currently the focus of exploration initiatives. The scientific value

John G. Spray; Lucy M. Thompson; Marc B. Biren; Catherine O’Connell-Cooper

2010-01-01

263

A multiparameter wearable physiologic monitoring system for space and terrestrial applications  

Microsoft Academic Search

A novel, unobtrusive and wearable, multiparameter ambulatory physiologic monitoring system for space and terrestrial applications, termed LifeGuard, is presented. The core element is a wearable monitor, the crew physiologic observation device (CPOD), that provides the capability to continuously record two standard electrocardiogram leads, respiration rate via impedance plethysmography, heart rate, hemoglobin oxygen saturation, ambient or body temperature, three axes of

Carsten W. Mundt; Kevin N. Montgomery; Usen E. Udoh; Valerie N. Barker; Guillaume C. Thonier; Arnaud M. Tellier; Robert D. Ricks; Robert B. Darling; Yvonne D. Cagle; Nathalie A. Cabrol; Stephen J. Ruoss; Judith L. Swain; John W. Hines; Gregory T. A. Kovacs

2005-01-01

264

The Effect of Tidal Interaction with a Gas Disk on Formation of Terrestrial Planets  

Microsoft Academic Search

We have performed N-body simulation on final accretion stage of terrestrial planets, including the effect of damping of eccentricity and inclination caused by tidal interaction with a remnant gas disk. As a result of runway and oligarchic accretion, about 20 Mars-sized protoplanets would be formed in nearly circular orbits with orbital separation of several to ten Hill radius. The orbits

Junko Kominami; Shigeru Ida

2002-01-01

265

Occurrence of giant impacts during the growth of the terrestrial planets  

Microsoft Academic Search

Three dimensional Monte Carlo simulations of the accumulation of the terrestrial planets in the absence of gas drag produced results that are in general agreement with the number and distribution of the present planets. The accumulation process appears to be characterized by impact of bodies as large as three times the mass of Mars at velocities of about 9 kilometers

G. W. WETHERILL

1985-01-01

266

Dynamical Stability of Terrestrial Mass Planets in and around the Habitable Zones of Single Planet Systems  

Microsoft Academic Search

We discuss the dynamical stability of hypothetical terrestrial mass planets (1 -10 Earth masses) in the habitable zone (HZ) of systems which have an additional massive planet. We consider arbitrary masses and orbits, which cover the range of observed planetary system architectures. We determine stability through N-body simulations which we compare to the analytic \\

Ravi Kumar Kopparapu; R. Barnes

2010-01-01

267

Dynamical stability of terrestrial mass planets in and around the habitable zones of single planet systems  

Microsoft Academic Search

We discuss the dynamical stability of hypothetical terrestrial mass planets (1 -10 Earth masses) in the habitable zone (HZ) of systems which have an additional massive planet. We consider arbitrary masses and orbits, which cover the range of observed planetary system architectures. We determine stability through N-body simulations which we compare to the analytic \\

R. Kopparapu; R. Barnes

2009-01-01

268

Peatland geoengineering: an alternative approach to terrestrial carbon sequestration.  

PubMed

Terrestrial and oceanic ecosystems contribute almost equally to the sequestration of ca 50 per cent of anthropogenic CO(2) emissions, and already play a role in minimizing our impact on Earth's climate. On land, the majority of the sequestered carbon enters soil carbon stores. Almost one-third of that soil carbon can be found in peatlands, an area covering just 2-3% of the Earth's landmass. Peatlands are thus well established as powerful agents of carbon capture and storage; the preservation of archaeological artefacts, such as ancient bog bodies, further attest to their exceptional preservative properties. Peatlands have higher carbon storage densities per unit ecosystem area than either the oceans or dry terrestrial systems. However, despite attempts over a number of years at enhancing carbon capture in the oceans or in land-based afforestation schemes, no attempt has yet been made to optimize peatland carbon storage capacity or even to harness peatlands to store externally captured carbon. Recent studies suggest that peatland carbon sequestration is due to the inhibitory effects of phenolic compounds that create an 'enzymic latch' on decomposition. Here, we propose to harness that mechanism in a series of peatland geoengineering strategies whereby molecular, biogeochemical, agronomical and afforestation approaches increase carbon capture and long-term sequestration in peat-forming terrestrial ecosystems. PMID:22869805

Freeman, Christopher; Fenner, Nathalie; Shirsat, Anil H

2012-09-13

269

Lunar and Terrestrial Planet Formation in the Grand Tack Scenario  

E-print Network

We present conclusions from a large number of N-body simulations of the giant impact phase of terrestrial planet formation. We focus on new results obtained from the recently proposed Grand Tack model, which couples the gas-driven migration of giant planets to the accretion of the terrestrial planets. The giant impact phase follows the oligarchic growth phase, which builds a bi-modal mass distribution within the disc of embryos and planetesimals. By varying the ratio of the total mass in the embryo population to the total mass in the planetesimal population and the mass of the individual embryos, we explore how different disc conditions control the final planets. The total mass ratio of embryos to planetesimals controls the timing of the last giant (Moon forming) impact and its violence. The initial embryo mass sets the size of the lunar impactor and the growth rate of Mars. After comparing our simulated outcomes with the actual orbits of the terrestrial planets (angular momentum deficit, mass concentration) ...

Jacobson, Seth A

2014-01-01

270

Thrash, flip, or jump: the behavioral and functional continuum of terrestrial locomotion in teleost fishes.  

PubMed

Moving on land versus in water imposes dramatically different requirements on the musculoskeletal system. Although many limbed vertebrates, such as salamanders and prehistoric tetrapodomorphs, have an axial system specialized for aquatic locomotion and an appendicular system adapted for terrestrial locomotion, diverse extant teleosts use the axial musculoskeletal system (body plus caudal fin) to move in these two physically disparate environments. In fact, teleost fishes living at the water's edge demonstrate diversity in natural history that is reflected in a variety of terrestrial behaviors: (1) species that have only incidental contact with land (such as largemouth bass, Micropterus) will repeatedly thrash, which can roll an individual downhill, but cannot produce effective overland movements, (2) species that have occasional contact with land (like Gambusia, the mosquitofish, which evade predators by stranding themselves) will produce directed terrestrial movement via a tail-flip jump, and (3) species that spend more than half of their lives on land (like the mudskipper, Periopthalmus) will produce a prone-jump, a behavior that allows the fish to anticipate where it will land at the end of the flight phase. Both tail-flip and prone jumps are characterized by a two-phase movement consisting of body flexion followed by extension-a movement pattern that is markedly similar to the aquatic fast-start. Convergence in kinematic pattern between effective terrestrial behaviors and aquatic fast starts suggests that jumps are an exaptation of a neuromuscular system that powers unsteady escape behaviors in the water. Despite such evidence that terrestrial behaviors evolved from an ancestral behavior that is ubiquitous among teleosts, some teleosts are unable to move effectively on land-possibly due to morphological trade-offs, wherein specialization for one environment comes at a cost to performance in the other. Indeed, upon emergence onto land, gravity places an increased mechanical load on the body, which may limit the maximum size of fish that can produce terrestrial locomotion via jumping. In addition, effective terrestrial locomotor performance may require a restructuring of the musculoskeletal system that directly conflicts with the low-drag, fusiform body shape that enhances steady swimming performance. Such biomechanical trade-offs may constrain which teleost species are able to make the evolutionary transition to life on land. Here, we synthesize the current knowledge of intermittent terrestrial locomotion in teleosts and demonstrate that extant fishes represent an important model system for elucidating fundamental evolutionary mechanisms and defining the physiological constraints that must be overcome to permit life in both the aquatic and terrestrial realms. PMID:23704366

Gibb, Alice C; Ashley-Ross, Miriam A; Hsieh, S Tonia

2013-08-01

271

Large Extra Dimension and Dark Matter Detection  

SciTech Connect

If our space has the large extra dimensions as proposed by Arkani-Hamed, Dimopoulos and Dvali (ADD), then gravity would start to deviate from Newtonian gravity and be greatly enhanced in sub-millimeter scales. Here we show that in the ADD scenario, gravity could play an important role (compared to the weak interaction) in the interactions between dark matter particles and the electron. We find that for typical WIMP dark matter, such dark matter-electron 'gravitational' scattering cross section may be much larger than the dark matter-nucleon cross section constrained by current dark matter experiments.

Qin Bo [National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China); Starkman, Glenn D. [Department of Physics, Case Western Reserve University, Cleveland, OH 44106-7079 (United States); Silk, Joseph [Astrophysics Department, University of Oxford, Oxford OX1 3RH (United Kingdom)

2008-01-03

272

Extra-Credit Problems in Space Science  

NSDL National Science Digital Library

These activities comprise a series of 20 practical math applications in space science. Students looking for additional challenges in math and physical science can use these as extra credit. The problems are authentic glimpses of modern engineering issues that arise in designing satellites to work in space. Each word problem has background information providing insight into the basic phenomena of the sun-Earth system, specifically space weather. The one-page assignments are accompanied by one-page teachers guides with answer keys.

2007-01-01

273

Extra Dimensions: A View from the Top  

E-print Network

In models with compact extra dimensions, where the Standard Model fields are confined to a 3+1 dimensional hyperplane, the $t \\bar t$ production cross-section at a hadron collider can receive significant contributions from multiple exchange of KK modes of the graviton. These are carefully computed in the well-known ADD and RS scenarios, taking the energy dependence of the sum over graviton propagators into account. Using data from Run-I of the Tevatron, 95% C.L. bounds on the parameter space of both models are derived. For Run-II of the Tevatron and LHC, discovery limits are estimated.

Smaragda Lola; Prakash Mathews; Sreerup Raychaudhuri; K. Sridhar

2000-10-18

274

Mars: destruction of the tropical belt and building up extra tropics is a physical requirement of angular momentum equilibration between zones with different distances to the rotation axis  

NASA Astrophysics Data System (ADS)

Often observed a sensible difference in appearance and structure between tropical and extra-t ropical zones of various heavenly bodies including rocky and gas planets, satellites and Sun (Fig. 6) compels to look for a common reason of such phenomenon [1-3]. All bodies rotate and their spherical shape makes zones at different lat itudes to have differing angular momenta as a distance to the rotation axis diminishes gradually from the equator to the poles (Fig. 1) (this is felt particularly when one launches rockets into space -preferable cheaper launches are from the equatorial regions - Kourou in the French Guyana is better than Baikonur in Kazakhstan). One of remarkable changes occurs at tropics. As a total rotating planetary body tends to have angular momenta of its tectonic blocks equilibrated it starts mechanisms leveling this basic physical property. At tropical zones (bulged also due to the rotation ellipsoid) the outer shell - crust as a consequence tends to be destroyed, sunk, subsided and shrunk; a density of crust material changes; the atmosphere reacts changing chemistry and structure; in terrestrial anthroposphere man looses its mass and stature (well known pygmioidness process). Ext ratropical belts, on the contrary, tend to add material and increase radius. Thus, a body tends to be like a cucumber but mighty gravity always makes it globular. According to the Le Chatelier rule mechanisms with opposing tendencies also begin to act. However, traces of this cosmic "struggle" very often are seen on surfaces of heavenly bodies as structurally distinguished tropical and extra-t ropical zones (Fig. 1, 6) [1-3]. At Mars the widespread "enigmatic" chaotic and fretted terrains at the highland-lowland boundary could be considered as traces of the crust destruction along the wide tropical belt (Fig. 2-4). A system of hillocks and their relics, mesas, ridges, cliffs and separating them depressions or plains (deep up to 1-2 km) is controlled by a crosscutting tectonics or makes a complicated mix (Fig. 3, 4). Prevailing subsidence here is characteristic. The depressions were used and additionally sculptured by moving ices and flowing waters in the past of martian geologic history. On the contrary, wide extra -tropical belts of pedestal craters with broad effusions of fluid-rich material (Fig. 5) obviously help to mend defective momentum. A comparison with Earth is to the point. There also the wide planetary long tropical zone is marked by destruction of the crust. It is demonstrated by development of numerous islands of the Malay Archipelago (the Sunda Isls., Maluku Isls., Philippines) between the Southeastern Asia and Australia. In Africa and South America huge depressions of the Congo and Amazon Rivers develop where the Archean crust is subsided to depths of more than 2 km. In the Pacific along the equator numerous islands of Micronesia occur (massive corals mark subsiding basaltic summits). Subsidence of the basaltic oceanic crust is followed by an intensive folding and faulting of basalt and sedimentary layers as a larger mass must be held by a smaller space (a planetary radius is diminishing). The central Atlantic is very demonstrative in this sense suffering huge transform fault zones being replaced by more quite tectonics to the north and south where basaltic effusions (plateau-basalts) form large provinces. This addition of dense basalts to the upper crust level helps to increase angular momentum of the extra-t ropical blocks. Recent results from the DAWN mission show that the mini-planet Vesta also has the same structurally deformed equatorial belt. But at Vesta the equatorial belt is subsided and faulted (broken by tight series of parallel grabens) having been squeezed into smaller space because of diminishing planetary radius (Fig. 6) Thus, Mars, as other planetary bodies, suffers a fundamental re-building of its wide topical zone (supertectonics) as a necessary natural response to the angular momentum adjustment (equilibrat ion) of its different latitude belts (tropics and extra-tropics). Th

Kochemasov, G. G.

2012-09-01

275

Energetic Strategies of Terrestrial Vertebrates  

NSDL National Science Digital Library

This laboratory exercise investigates the difference in metabolic response of representative endotherms (mice) and ectotherms (green anoles) to temperature changes and ecological consequences are studied through behavior and preferred body temperature in a temperature gradient.

Kathy Winnett-Murray (Hope College; )

2000-01-01

276

Pathological Bodies  

E-print Network

of the Modern Body: Sexuality and Society in the Nineteenthof the Modern Body: Sexuality and Society in the Nineteenthsexuality, human “nature,” racial difference, disease, and our own destructive impulses give birth to society’

Wagner, Corinna

2013-01-01

277

Body Image  

MedlinePLUS

... Body dysmorphic disorder (BDD) Eating disorders Anorexia nervosa Binge eating disorder Bulimia nervosa Over-exercising Pregnancy and body ... our Mental health section. Fact sheets Anorexia nervosa Binge eating disorder Bulimia nervosa Cosmetics and your health Depression ...

278

The influence of load carrying on the energetics and kinematics of terrestrial locomotion in a diving bird  

PubMed Central

Summary The application of artificial loads to mammals and birds has been used to provide insight into the mechanics and energetic cost of terrestrial locomotion. However, only two species of bird have previously been used in loading experiments, the cursorial guinea fowl (Numida meleagris) and the locomotor-generalist barnacle goose (Branta leucopsis). Here, using respirometry and treadmill locomotion, we investigate the energetic cost of carrying trunk loads in a diving bird, the tufted duck (Aythya fuligula). Attachment of back loads equivalent to 10% and 20% of body mass increased the metabolic rate during locomotion (7.94% and 15.92%, respectively) while sternal loads of 5% and 10% had a greater proportional effect than the back loads (metabolic rate increased by 7.19% and 13.99%, respectively). No effect on locomotor kinematics was detected during any load carrying experiments. These results concur with previous reports of load carrying economy in birds, in that there is a less than proportional relationship between increasing load and metabolic rate (found previously in guinea fowl), while application of sternal loads causes an approximate doubling of metabolic rate compared to back loads (reported in an earlier study of barnacle geese). The increase in cost when carrying sternal loads may result from having to move this extra mass dorso-ventrally during respiration. Disparity in load carrying economy between species may arise from anatomical and physiological adaptations to different forms of locomotion, such as the varying uncinate process morphology and hindlimb tendon development in goose, guinea fowl and duck. PMID:24244861

Tickle, Peter G.; Lean, Samantha C.; Rose, Kayleigh A. R.; Wadugodapitiya, Avanti P.; Codd, Jonathan R.

2013-01-01

279

The influence of load carrying on the energetics and kinematics of terrestrial locomotion in a diving bird.  

PubMed

The application of artificial loads to mammals and birds has been used to provide insight into the mechanics and energetic cost of terrestrial locomotion. However, only two species of bird have previously been used in loading experiments, the cursorial guinea fowl (Numida meleagris) and the locomotor-generalist barnacle goose (Branta leucopsis). Here, using respirometry and treadmill locomotion, we investigate the energetic cost of carrying trunk loads in a diving bird, the tufted duck (Aythya fuligula). Attachment of back loads equivalent to 10% and 20% of body mass increased the metabolic rate during locomotion (7.94% and 15.92%, respectively) while sternal loads of 5% and 10% had a greater proportional effect than the back loads (metabolic rate increased by 7.19% and 13.99%, respectively). No effect on locomotor kinematics was detected during any load carrying experiments. These results concur with previous reports of load carrying economy in birds, in that there is a less than proportional relationship between increasing load and metabolic rate (found previously in guinea fowl), while application of sternal loads causes an approximate doubling of metabolic rate compared to back loads (reported in an earlier study of barnacle geese). The increase in cost when carrying sternal loads may result from having to move this extra mass dorso-ventrally during respiration. Disparity in load carrying economy between species may arise from anatomical and physiological adaptations to different forms of locomotion, such as the varying uncinate process morphology and hindlimb tendon development in goose, guinea fowl and duck. PMID:24244861

Tickle, Peter G; Lean, Samantha C; Rose, Kayleigh A R; Wadugodapitiya, Avanti P; Codd, Jonathan R

2013-01-01

280

Terrestrial Mammals of the Riparian Corridor  

E-print Network

Terrestrial Mammals of the Riparian Corridor in Big Bend National Park1 William J. Boeer and David J. Schmidly2 Abstract.--Thirty species of terrestrial mammals inhabit riparian habitats in Big and Peromyscus leucopus). Compared to the other major plant communities in BBNP, the rodent fauna of the riparian

281

Aerospace Power Technology for Potential Terrestrial Applications  

NASA Technical Reports Server (NTRS)

Aerospace technology that is being developed for space and aeronautical applications has great potential for providing technical advances for terrestrial power systems. Some recent accomplishments arising from activities being pursued at the National Aeronautics and Space Administration (NASA) Centers is described in this paper. Possible terrestrial applications of the new aerospace technology are also discussed.

Lyons, Valerie J.

2012-01-01

282

Automatic building modeling from terrestrial laser scanning  

E-print Network

hard to recover 3D building structures from 2D image. Recent studies ([2] [6]) show that laser scanning imagery, airborne and terrestrial laser scanning give explicit 3D information, which enables the rapidAutomatic building modeling from terrestrial laser scanning Shi Pu International Institute for Geo

Pu, Shi

283

Abundance of Terrestrial Planets by Microlensing  

E-print Network

Terrestrial planets may be detected using the gravitational microlensing technique. This was demonstrated in the high magnification event MACHO-98-BLG-35. Observing strategies aimed at measuring the abundance of terrestrial planets are discussed, using both existing telescopes and planned telescopes.

Philip Yock

2000-04-04

284

Flavor Structure of Warped Extra Dimension Models  

SciTech Connect

We recently showed, in hep-ph/0406101, that warped extra dimensional models with bulk custodial symmetry and few TeV KK masses lead to striking signals at B-factories. In this paper, using a spurion analysis, we systematically study the flavor structure of models that belong to the above class. In particular we find that the profiles of the zero modes, which are similar in all these models, essentially control the underlying flavor structure. This implies that our results are robust and model independent in this class of models. We discuss in detail the origin of the signals in B-physics. We also briefly study other NP signatures that arise in rare K decays (K {yields} {pi}{nu}{nu}), in rare top decays [t {yields} c{gamma}(Z, gluon)] and the possibility of CP asymmetries in D{sup 0} decays to CP eigenstates such as K{sub s}{pi}{sup 0} and others. Finally we demonstrate that with light KK masses, {approx} 3 TeV, the above class of models with anarchic 5D Yukawas has a ''CP problem'' since contributions to the neutron electric dipole moment are roughly 20 times larger than the current experimental bound. Using AdS/CFT correspondence, these extra-dimensional models are dual to a purely 4D strongly coupled conformal Higgs sector thus enhancing their appeal.

Agashe, Kaustubh; Perez, Gilad; Soni, Amarjit

2004-08-10

285

Accelerating Universe from Extra Spatial Dimension  

E-print Network

We present a simple higher dimensional FRW type of model where the acceleration is apparently caused by the presence of the extra dimensions. Assuming an ansatz in the form of the deceleration parameter we get a class of solutions some of which shows the desirable feature of dimensional reduction as well as reasonably good physical properties of matter. Interestingly we do not have to invoke an extraneous scalar field or a cosmological constant to account for this acceleration. One argues that the terms containing the higher dimensional metric coefficients produces an extra negative pressure that apparently drives the inflation of the 4D space with an accelerating phase. It is further found that in line with the physical requirements our model admits of a decelerating phase in the early era along with an accelerating phase at present.Further the models asymptotically mimic a steady state type of universe although it starts from a big type of singularity. Correspondence to Wesson's induced matter theory is also briefly discussed and in line with it it is argued that the terms containing the higher dimensional metric coefficients apparently creates a negative pressure which drives the inflation of the 3-space with an accelerating phase.

S. Chatterjee; A. Banerjee; Y. Z. Zhang

2005-09-28

286

Accelerating Universe from Extra Spatial Dimension  

E-print Network

We present a simple higher dimensional FRW type of model where the acceleration is apparently caused by the presence of the extra dimensions. Assuming an ansatz in the form of the deceleration parameter we get a class of solutions some of which shows the desirable feature of dimensional reduction as well as reasonably good physical properties of matter. Interestingly we do not have to invoke an extraneous scalar field or a cosmological constant to account for this acceleration. One argues that the terms containing the higher dimensional metric coefficients produces an extra negative pressure that apparently drives the inflation of the 4D space with an accelerating phase. It is further found that in line with the physical requirements our model admits of a decelerating phase in the early era along with an accelerating phase at present.Further the models asymptotically mimic a steady state type of universe although it starts from a big type of singularity. Correspondence to Wesson's induced matter theory is als...

Chatterjee, S; Zhang, Y Z

2006-01-01

287

Accelerating Universe from Extra Spatial Dimension  

NASA Astrophysics Data System (ADS)

We present a simple higher dimensional FRW-type of model where the acceleration is apparently caused by the presence of the extra dimensions. Assuming an ansatz in the form of the deceleration parameter, we get a class of solutions some of which shows the desirable feature of dimensional reduction as well as reasonably good physical properties of matter. Interestingly we do not have to invoke an extraneous scalar field or a cosmological constant to account for this acceleration. One argues that the terms containing the higher dimensional metric coefficients produces an extra negative pressure that apparently drives the inflation of the 4D space with an accelerating phase. It is further found that in line with the physical requirements our model admits of a decelerating phase in the early era along with an accelerating phase at present. Further the models asymptotically mimic a steady-state-type of universe although it starts from a big-bang-type of singularity. Correspondence to Wesson's induced matter theory is also briefly discussed and, in line with it, it is argued that the terms containing the higher dimensional metric coefficients apparently creates a negative pressure which drives the inflation of the 3-space with an accelerating phase.

Chatterjee, S.; Banerjee, A.; Zhang, Y. Z.

288

Warped Extra Dimensional Benchmarks for Snowmass 2013  

E-print Network

The framework of a warped extra dimension with the Standard Model (SM) fields propagating in it is a very well-motivated extension of the SM since it can address both the Planck-weak and flavor hierarchy problems of the SM. We consider signals at the 14 and 33 TeV large hadron collider (LHC) resulting from the direct production of the new particles in this framework, i.e.,Kaluza-Klein (KK) excitations of the SM particles. We focus on spin-1 (gauge boson) and spin-2 (graviton) KK particles and their decays to top/bottom quarks (flavor-conserving) and W/Z and Higgs bosons, in particular. We propose two benchmarks for this purpose, with the right-handed (RH) or LH top quark, respectively, being localized very close to the TeV end of the extra dimension. We present some new results at the 14 TeV (with 300 fb$^-1$ and 3000 fb$^-1$) and 33 TeV LHC. We find that the prospects for discovery of these particles are quite promising, especially at the high-luminosity upgrade.

Kaustubh Agashe; Oleg Antipin; Mihailo Backovi?; Aaron Effron; Alex Emerman; Johannes Erdmann; Tobias Golling; Shrihari Gopalakrishna; Tuomas Hapola; Shih-Chieh Hsu; José Juknevich; Seung J. Lee; Tanumoy Mandal; August Miller; Edward Moyse; Tuhin Subhra Mukherjee; Chris Pollard; Soumya Sadhukhan; Daniel Whiteson; Stephane Willocq

2013-09-30

289

Search for extra-solar planets  

NASA Astrophysics Data System (ADS)

A number of different observational techniques are used today for the detection of planets beyond our solar system. Most of them are indirect methods, based on dynamical or photometric effects induced by the planet and measured on the parent star. The most successful technique so far has been the Doppler (radial-velocity) method, based on precise measurements of small variations in the radial velocity of the parent star. About one hundred extra-solar planets have been discovered by this technique. Other methods are based on astrometric measurements, direct imaging, photometry, interferometry and gravitational microlensing. Some of these techniques are already able to produce positive results, but many of them are future projects needing more advanced instrumentation. In this paper the most important techniques for extra-solar planet detection will be reviewed and their results summarized. In the second part, two different projects carried out at Mt John University Observatory, Lake Tekapo, New Zealand will be presented, both involved in planet hunting. One is the HERCULES radial-velocity programme and the other is the MOA microlensing project.

Skuljan, J.

2003-10-01

290

The EXTraS project: Exploring the X-ray Transient and variable Sky  

NASA Astrophysics Data System (ADS)

Modern X-ray observatories can yield unique insights into time domain astrophysics. Indeed, a huge amount of information is already stored - and largely unexploited - in data archives. The EXTraS project will harvest the hitherto unexplored temporal domain information buried in the serendipitous data collected by the European Photon Imaging Camera (EPIC) instrument onboard the ESA XMM-Newton mission since its launch. This will include a search for fast transients, missed by standard image analysis, and a search and characterization of variability (both periodic and aperiodic) in hundreds of thousands of sources spanning more than nine orders of magnitude in time scale (from <1 s to >10 yr) and six orders of magnitude in flux (from 10^{-9} to 10^{-15} erg cm^{-2} s^{-1} in 0.2-12 keV). X-ray results will be complemented by multiwavelength characterization of new discoveries. Phenomenological classification of variable sources will also be performed. Our final catalogue and results will be made available to the community, together with new analysis tools, at the end of the project (late 2016). EXTraS is funded within the EU/FP7-Cooperation Space framework and is carried out by a collaboration including INAF (Italy), IUSS (Italy), CNR/IMATI (Italy), University of Leicester (UK), MPE (Germany) and ECAP (Germany).

De Luca, A.; D'Agostino, D.; Haberl, F.; Tiengo, A.; Watson, M.; Wilms, J.

2014-07-01

291

Can polar bears use terrestrial foods to offset lost ice-based hunting opportunities?  

USGS Publications Warehouse

Increased land use by polar bears (Ursus maritimus) due to climate-change-induced reduction of their sea-ice habitat illustrates the impact of climate change on species distributions and the difficulty of conserving a large, highly specialized carnivore in the face of this global threat. Some authors have suggested that terrestrial food consumption by polar bears will help them withstand sea-ice loss as they are forced to spend increasing amounts of time on land. Here, we evaluate the nutritional needs of polar bears as well as the physiological and environmental constraints that shape their use of terrestrial ecosystems. Only small numbers of polar bears have been documented consuming terrestrial foods even in modest quantities. Over much of the polar bear's range, limited terrestrial food availability supports only low densities of much smaller, resident brown bears (Ursus arctos), which use low-quality resources more efficiently and may compete with polar bears in these areas. Where consumption of terrestrial foods has been documented, polar bear body condition and survival rates have declined even as land use has increased. Thus far, observed consumption of terrestrial food by polar bears has been insufficient to offset lost ice-based hunting opportunities but can have ecological consequences for other species. Warming-induced loss of sea ice remains the primary threat faced by polar bears.

Rode, Karyn D.; Robbins, Charles T.; Nelson, Lynne; Amstrup, Steven C.

2015-01-01

292

Terrestrial gamma-ray flashes  

NASA Astrophysics Data System (ADS)

Lightning and thunderstorm systems in general have been recently recognized as powerful particle accelerators, capable of producing electrons, positrons, gamma-rays and neutrons with energies as high as several tens of MeV. In fact, these natural systems turn out to be the highest energy and most efficient natural particle accelerators on Earth. Terrestrial Gamma-ray Flashes (TGFs) are millisecond long, very intense bursts of gamma-rays and are one of the most intriguing manifestation of these natural accelerators. Only three currently operative missions are capable of detecting TGFs from space: the RHESSI, Fermi and AGILE satellites. In this paper we review the characteristics of TGFs, including energy spectrum, timing structure, beam geometry and correlation with lightning, and the basic principles of the associated production models. Then we focus on the recent AGILE discoveries concerning the high energy extension of the TGF spectrum up to 100 MeV, which is difficult to reconcile with current theoretical models.

Marisaldi, Martino; Fuschino, Fabio; Labanti, Claudio; Tavani, Marco; Argan, Andrea; Del Monte, Ettore; Longo, Francesco; Barbiellini, Guido; Giuliani, Andrea; Trois, Alessio; Bulgarelli, Andrea; Gianotti, Fulvio; Trifoglio, Massimo

2013-08-01

293

Phytopharmacological overview of Tribulus terrestris  

PubMed Central

Tribulus terrestris (family Zygophyllaceae), commonly known as Gokshur or Gokharu or puncture vine, has been used for a long time in both the Indian and Chinese systems of medicine for treatment of various kinds of diseases. Its various parts contain a variety of chemical constituents which are medicinally important, such as flavonoids, flavonol glycosides, steroidal saponins, and alkaloids. It has diuretic, aphrodisiac, antiurolithic, immunomodulatory, antidiabetic, absorption enhancing, hypolipidemic, cardiotonic, central nervous system, hepatoprotective, anti-inflammatory, analgesic, antispasmodic, anticancer, antibacterial, anthelmintic, larvicidal, and anticariogenic activities. For the last few decades or so, extensive research work has been done to prove its biological activities and the pharmacology of its extracts. The aim of this review is to create a database for further investigations of the discovered phytochemical and pharmacological properties of this plant to promote research. This will help in confirmation of its traditional use along with its value-added utility, eventually leading to higher revenues from the plant. PMID:24600195

Chhatre, Saurabh; Nesari, Tanuja; Somani, Gauresh; Kanchan, Divya; Sathaye, Sadhana

2014-01-01

294

Line following terrestrial insect biobots.  

PubMed

The present day technology falls short in offering centimeter scale mobile robots that can function effectively under unknown and dynamic environmental conditions. Insects, on the other hand, exhibit an unmatched ability to navigate through a wide variety of environments and overcome perturbations by successfully maintaining control and stability. In this study, we use neural stimulation systems to wirelessly navigate cockroaches to follow lines to enable terrestrial insect biobots. We also propose a system-on-chip based ZigBee enabled wireless neurostimulation backpack system with on-board tissue-electrode bioelectrical coupling verification. Such a capability ensures an electrochemically safe stimulation and avoids irreversible damage to the interface which is often misinterpreted as habituation of the insect to the applied stimulation. PMID:23366056

Latif, Tahmid; Bozkurt, Alper

2012-01-01

295

Methane production in terrestrial arthropods.  

PubMed Central

We have screened more than 110 representatives of the different taxa of terrestrial arthropods for methane production in order to obtain additional information about the origins of biogenic methane. Methanogenic bacteria occur in the hindguts of nearly all tropical representatives of millipedes (Diplopoda), cockroaches (Blattaria), termites (Isoptera), and scarab beetles (Scarabaeidae), while such methanogens are absent from 66 other arthropod species investigated. Three types of symbiosis were found: in the first type, the arthropod's hindgut is colonized by free methanogenic bacteria; in the second type, methanogens are closely associated with chitinous structures formed by the host's hindgut; the third type is mediated by intestinal anaerobic protists with intracellular methanogens. Such symbiotic associations are likely to be a characteristic property of the particular taxon. Since these taxa represent many families with thousands of species, the world populations of methane-producing arthropods constitute an enormous biomass. We show that arthropod symbionts can contribute substantially to atmospheric methane. Images PMID:8202505

Hackstein, J H; Stumm, C K

1994-01-01

296

Terrestrial Ages of Antarctic Meteorites- Update 1999  

NASA Technical Reports Server (NTRS)

We are continuing our ongoing study of cosmogenic nuclides in Antarctic meteorites. In addition to the studies of exposure histories of meteorites, we study terrestrial ages and pairing of Antarctic meteorites and desert meteorites. Terrestrial ages of Antarctic meteorites provide information on meteorite accumulation mechanisms, mean weathering lifetimes, and influx rates. The determination of Cl-36(half-life=3.01 x 10(exp 5) y) terrestrial ages is one of our long-term on-going projects, however, in many instances neither Cl-36 or C-14 (5,730 y) yields an accurate terrestrial age. Using Ca-14 (1.04 x 10(exp 5) y) for terrestrial age determinations solves this problem by filling the c,ap in half-life between 14-C and Cl-36 ages. We are now applying the new Ca-41- Cl-36 terrestrial age method as well as the Cl-36-Be-10 method to Antarctic meteorites. Our measurements and C-14 terrestrial age determinations by the University of Arizona group are always complementary. We have measured Cl-36 in over 270 Antarctic meteorites since our previous compilation of terrestrial ages. Since a large number of meteorites have been recovered from many different icefields in Antarctica, we continue to survey the trends of terrestrial ages for different icefields. We have also measured detailed terrestrial ages vs. sample locations for Allan Hills, Elephant Moraine, and Lewis Cliff Icefields, where meteorites have been found with very long ages. The updated histograms of terrestrial ages of meteorites from the Allan Hills Main Icefield and Lewis Cliff Icefield are shown. These figures include C-14 ages obtained by the University of Arizona group. Pairs of meteorites are shown as one object for which the age is the average of all members of the same fall. The width of the bars represents 70,000 years, which was a typical uncertainty for Cl-36 ages. We reduced the uncertainty of terrestrial age determinations to approx. 40,000 years by using pairs of nuclides such as Ca-41-Cl-36 or Cl-36-Be-10. Meteorites found at the Allan Hills Icefields are much older than any other meteorites. The terrestrial ages cover a wide range and are as old as 2 My. Many of the Lewis Cliff meteorites are as old as the Allan Hills meteorites. So far, no clear correlation has been found between the terrestrial ages and the locations of the Lewis Cliff meteorites.

Nishiizumi, Kunihiko; Welten, K. C.; Caffee, Marc W.

1999-01-01

297

Extreme Terrestrial Gamma ray Events  

NASA Astrophysics Data System (ADS)

Terrestrial gamma ray flashes were first discovered by the Compton GRO observatory and such event have been observed later on-board Rhessi satellite and more recently by the Fermi and Agile missions. These events are believed to be associated with the thunderstorm activity in the lower atmosphere. When observed from the satellite instruments, the observed time structure. Shows short milliseconds bursts probably due to lightning discharges , however an other type of long bursts with a duration of a few seconds to a few minutes have been observed only in the lower atmosphere. Such behaviour is natural as the upward moving photons go through a large atmospheric depth several 100 gms which will affect both the time structure and the spectral nature as the thunderstorms normally originate only in the lower troposphere just above the convective boundary layer. We report the observations of extreme terrestrial gamma ray events with time duration ~150-250 min observed during the thunderstorm activity in Hyderabad South, India. At 17.3o lat. and 78.6o long., Hyderabad is located in the convergence zone with high level of thunderstorm activity during the monsoon period. Spectral data suggest a continuum flux of the gamma ray from 100 keV to 10 MeV for hours. Temporal characteristics studied with time resolution of 100 microsec do not show any excess power density at any frequency. The data suggest that unlike gamma ray flashes which are generated just during the lightening flash, large electric field disturbances during long thunderstorm activity may lead to large flux of accelerated particles, which emit continuum gamma rays flux.

Manchanda, R. K.; Kamble, Nilima

2012-07-01

298

A Spherical Aerial Terrestrial Robot  

NASA Astrophysics Data System (ADS)

This thesis focuses on the design of a novel, ultra-lightweight spherical aerial terrestrial robot (ATR). The ATR has the ability to fly through the air or roll on the ground, for applications that include search and rescue, mapping, surveillance, environmental sensing, and entertainment. The design centers around a micro-quadcopter encased in a lightweight spherical exoskeleton that can rotate about the quadcopter. The spherical exoskeleton offers agile ground locomotion while maintaining characteristics of a basic aerial robot in flying mode. A model of the system dynamics for both modes of locomotion is presented and utilized in simulations to generate potential trajectories for aerial and terrestrial locomotion. Details of the quadcopter and exoskeleton design and fabrication are discussed, including the robot's turning characteristic over ground and the spring-steel exoskeleton with carbon fiber axle. The capabilities of the ATR are experimentally tested and are in good agreement with model-simulated performance. An energy analysis is presented to validate the overall efficiency of the robot in both modes of locomotion. Experimentally-supported estimates show that the ATR can roll along the ground for over 12 minutes and cover the distance of 1.7 km, or it can fly for 4.82 minutes and travel 469 m, on a single 350 mAh battery. Compared to a traditional flying-only robot, the ATR traveling over the same distance in rolling mode is 2.63-times more efficient, and in flying mode the system is only 39 percent less efficient. Experimental results also demonstrate the ATR's transition from rolling to flying mode.

Dudley, Christopher J.

299

Insignificant solar-terrestrial triggering of earthquakes  

USGS Publications Warehouse

We examine the claim that solar-terrestrial interaction, as measured by sunspots, solar wind velocity, and geomagnetic activity, might play a role in triggering earthquakes. We count the number of earthquakes having magnitudes that exceed chosen thresholds in calendar years, months, and days, and we order these counts by the corresponding rank of annual, monthly, and daily averages of the solar-terrestrial variables. We measure the statistical significance of the difference between the earthquake-number distributions below and above the median of the solar-terrestrial averages by ?2 and Student's t tests. Across a range of earthquake magnitude thresholds, we find no consistent and statistically significant distributional differences. We also introduce time lags between the solar-terrestrial variables and the number of earthquakes, but again no statistically significant distributional difference is found. We cannot reject the null hypothesis of no solar-terrestrial triggering of earthquakes.

Love, Jeffrey J.; Thomas, Jeremy N.

2013-01-01

300

[Helicobacter pylori infection as a cause of extra-digestive diseases: myth or reality?].  

PubMed

The persistent inflammation of the stomach induced by Helicobacter pylori infection can have consequences on the rest of the body. In the last few years, many studies have been performed on the implication of H. pylori in the pathogenesis of extra-gastric diseases attempting to establish if this association is real. Many diseases may be associated with H. pylori, e.g. vascular diseases, autoimmune diseases, skin diseases, sideropenic anemia, diabetes, Parkinson disease, and bronchiectasis. The number of important studies revealing such associations suggests that pathogenic mechanisms may link this infection with many diseases of unknown etiology. Unfortunately, the quality of the studies performed is not homogeneous, and more rigorous investigations are required to show whether a causal link exists between H. pylori infection and the pathogenic processes of these extra-digestive diseases. PMID:12700503

Richy, Frédérique; Mégraud, Francis

2003-03-01

301

Astronomers Report Discovery of New Extra-solar Planets: Four Reports  

NSDL National Science Digital Library

If you are feeling alone in the universe, this news from 2000 of the search for new planets might inspire you. This account is from the popular space science Website, Space.com. It chronicles the latest detection of at least nine possible planetary bodies orbiting stars outside of our solar system. The text includes a discussion of how detection of wobble behavior is used in the search for extra-solar planets and plans for future planet hunts. This site also features links to Websites of the observatories involved in extra-solar planet detection, related Space.com stories, a diagram of Doppler shift due to stellar wobble and a table of the nine planet candidates's size and distance from Earth.

Weinstock, Maia.

2000-01-01

302

Studying silicate-ice bodies in the Solar System  

Microsoft Academic Search

Evolution of Small Silicate-Ice Bodies in the Solar System; Winthrop, Washington, 6-8 August 2010; Interest is growing in a class of small bodies in the solar system, some of which are believed to be the building blocks of the terrestrial planets. These include Ceres, Vesta, Pallas, the icy satellites, and some solid objects farther out in the solar system. Many

Thomas B. McCord; Julie C. Castillo-Rogez

2011-01-01

303

Scaling of the hydrostatic skeleton in the earthworm Lumbricus terrestris.  

PubMed

The structural and functional consequences of changes in size or scale have been well studied in animals with rigid skeletons, but relatively little is known about scale effects in animals with hydrostatic skeletons. We used glycol methacrylate histology and microscopy to examine the scaling of mechanically important morphological features of the earthworm Lumbricus terrestris over an ontogenetic size range from 0.03 to 12.89 g. We found that L. terrestris becomes disproportionately longer and thinner as it grows. This increase in the length to diameter ratio with size means that, when normalized for mass, adult worms gain ~117% mechanical advantage during radial expansion, compared with hatchling worms. We also found that the cross-sectional area of the longitudinal musculature scales as body mass to the ~0.6 power across segments, which is significantly lower than the 0.66 power predicted by isometry. The cross-sectional area of the circular musculature, however, scales as body mass to the ~0.8 power across segments, which is significantly higher than predicted by isometry. By modeling the interaction of muscle cross-sectional area and mechanical advantage, we calculate that the force output generated during both circular and longitudinal muscle contraction scales near isometry. We hypothesize that the allometric scaling of earthworms may reflect changes in soil properties and burrowing mechanics with size. PMID:24871920

Kurth, Jessica A; Kier, William M

2014-06-01

304

Background exposure rates of terrestrial wildlife in England and Wales.  

PubMed

It has been suggested that, when assessing radiation impacts on non-human biota, estimated dose rates due to anthropogenically released radionuclides should be put in context by comparison to dose rates from natural background radiation. In order to make these comparisons, we need data on the activity concentrations of naturally occurring radionuclides in environmental media and organisms of interest. This paper presents the results of a study to determine the exposure of terrestrial organisms in England and Wales to naturally occurring radionuclides, specifically (40)K, (238)U series and (232)Th series radionuclides. Whole-body activity concentrations for the reference animals and plants (RAPs) as proposed by the ICRP have been collated from literature review, data archives and a targeted sampling campaign. Data specifically for the proposed RAP are sparse. Soil activity concentrations have been derived from an extensive geochemical survey of the UK. Unweighted and weighted absorbed dose rates were estimated using the ERICA Tool. Mean total weighted whole-body absorbed dose rates estimated for the selected terrestrial organisms was in the range 6.9 x 10(-2) to 6.1 x 10(-1) microGy h(-1). PMID:18440107

Beresford, N A; Barnett, C L; Jones, D G; Wood, M D; Appleton, J D; Breward, N; Copplestone, D

2008-09-01

305

The extra-resonances of metamaterials in terahertz  

Microsoft Academic Search

Some new resonances (extra-resonances) are observed in the simulations of metamaterials in terahertz band. Utilizing the parameter energy balance, the existence of the extra-resonance has been proved. The extra-resonance is found can be affected by the structure of metamaterials and the thickness of the slab. An improved LC model with the consideration of the substrate slab is presented for metamaterials.

Yunsong Xie; Huaiwu Zhang; Qiye Wen; Yingli Liu; Yuanxun Li; Jian Guan

2008-01-01

306

MATE GUARDING AND EXTRA-PAIR PATERNITY IN NORTHERN CARDINALS  

Microsoft Academic Search

We studied patterns of mate guarding and paternity in 21 pairs of Northern Cardinals (Cardinalis cardinalis) nesting in~central_Kentucky. DbJA fingerprinting revealed that five of 37 nestlinas (13.5%) resulted from extra-pair fertilizations (EPFs). Of 19 broods sampled, three (16%)-bad at least one extra-pair young. Although our observations of male cardinals making extra-territorial movements suggest that some males in the population may

DAVID F. WESTNEAT

307

Chemical impurity produces extra compound eyes and heads in crickets  

SciTech Connect

A chemical impurity isolated from commercially purchased acridine causes cricket embryos to develop extra compound eyes, branched antennae, extra antennae, and extra heads. Purified acridine does not produce similar duplications of cricket heads or head structures nor do the substituted acridines proflavine, acriflavine, or acridine orange. A dose-response relation exists such that the number and severity of abnormalities increase with increasing concentration of the teratogen.

Walton, B.T.

1981-04-03

308

Extra-Axial Medulloblastoma in the Cerebellar Hemisphere  

PubMed Central

Extra-axial medulloblastoma is a rare phenomenon. We report a case in a 5-year-old boy who presented with nausea, vomiting, and gait disturbance. He was treated with total removal of the tumor. This is the first case of an extra-axially located medulloblastoma occurring in the cerebellar hemisphere posteriolateral to the cerebellopontine angle in Korea. Although the extra-axial occurrence of medulloblastoma is rare, it should be considered in the differential diagnosis of extra-axial lesions of the posterior fossa in children. PMID:25237434

Chung, Eui Jin

2014-01-01

309

Behavioral correlates of extra-pair copulation in Indri indri.  

PubMed

Active pursuit of extra-pair mating has been reported for Indri indri, the socially monogamous largest living lemur. This study, conducted in a mountain rainforest in eastern Madagascar, presents the first evidence for extra-pair mating of indri and discusses the alternative mating strategy and alteration of the social, territorial, spatial, and vocal behavior of the adult female of a group of wild indris. Further studies may investigate whether extra-pair copulation is an attempt to breed with a partner of superior quality and thus lead to extra-pair paternity. If so, it could potentially play a role in maintaining genetic variability within a population. PMID:23921557

Bonadonna, Giovanna; Torti, Valeria; Randrianarison, Rose Marie; Martinet, Nicole; Gamba, Marco; Giacoma, Cristina

2014-01-01

310

Body Weight and Body Image  

Microsoft Academic Search

HEALTH ISSUE: Body weight is of physical and psychological importance to Canadian women; it is associated with health status, physical activity, body image, and self-esteem. Although the problems associated with overweight and obesity are indeed serious, there are also problems connected to being underweight. Weight prejudice and the dieting industry intensify body image concerns for Canadian women and can have

Marion P. Olmsted; Traci McFarlane

2004-01-01

311

Gamma ray lines from a universal extra dimension  

SciTech Connect

Indirect Dark Matter searches are based on the observation of secondary particles produced by the annihilation or decay of Dark Matter. Among them, gamma-rays are perhaps the most promising messengers, as they do not suffer deflection or absorption on Galactic scales, so their observation would directly reveal the position and the energy spectrum of the emitting source. Here, we study the detailed gamma-ray energy spectrum of Kaluza-Klein Dark Matter in a theory with 5 Universal Extra Dimensions. We focus in particular on the two body annihilation of Dark Matter particles into a photon and another particle, which produces monochromatic photons, resulting in a line in the energy spectrum of gamma rays. Previous calculations in the context of the five dimensional UED model have computed the line signal from annihilations into ??, but we extend these results to include ?Z and ?H final states. We find that these spectral lines are subdominant compared to the predicted ?? signal, but they would be important as follow-up signals in the event of the observation of the ?? line, in order to distinguish the 5d UED model from other theoretical scenarios.

Bertone, Gianfranco [Institut for Theoretical Physics, Univ. of Zürich, Winterthurerst. 190, 8057 Zürich CH (Switzerland); Jackson, C. B. [Department of Physics, University of Texas at Arlington, Arlington, TX 76019 (United States); Shaughnessy, Gabe [High Energy Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Tait, Tim M.P. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Vallinotto, Alberto, E-mail: G.Bertone@uva.nl, E-mail: cbjackson@uta.edu, E-mail: gshau@hep.wisc.edu, E-mail: ttait@uci.edu, E-mail: avallino@gmail.com [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

2012-03-01

312

Gamma ray lines from a universal extra dimension  

SciTech Connect

Indirect Dark Matter searches are based on the observation of secondary particles produced by the annihilation or decay of Dark Matter. Among them, gamma-rays are perhaps the most promising messengers, as they do not suffer deflection or absorption on Galactic scales, so their observation would directly reveal the position and the energy spectrum of the emitting source. Here, we study the detailed gamma-ray energy spectrum of Kaluza--Klein Dark Matter in a theory with 5 Universal Extra Dimensions. We focus in particular on the two body annihilation of Dark Matter particles into a photon and another particle, which produces monochromatic photons, resulting in a line in the energy spectrum of gamma rays. Previous calculations in the context of the five dimensional UED model have computed the line signal from annihilations into \\gamma \\gamma, but we extend these results to include \\gamma Z and \\gamma H final states. We find that these spectral lines are subdominant compared to the predicted \\gamma \\gamma signal, but they would be important as follow-up signals in the event of the observation of the \\gamma \\gamma line, in order to distinguish the 5d UED model from other theoretical scenarios.

Bertone, Gianfranco; Jackson, C.B.; Shaughnessy, Gabe; Tait, Tim M.P.; Vallinotto, Alberto

2012-03-01

313

FORMATION OF TERRESTRIAL PLANETS FROM PROTOPLANETS UNDER A REALISTIC ACCRETION CONDITION  

SciTech Connect

The final stage of terrestrial planet formation is known as the giant impact stage where protoplanets collide with one another to form planets. So far this stage has been mainly investigated by N-body simulations with an assumption of perfect accretion in which all collisions lead to accretion. However, this assumption breaks for collisions with high velocity and/or a large impact parameter. We derive an accretion condition for protoplanet collisions in terms of impact velocity and angle and masses of colliding bodies, from the results of numerical collision experiments. For the first time, we adopt this realistic accretion condition in N-body simulations of terrestrial planet formation from protoplanets. We compare the results with those with perfect accretion and show how the accretion condition affects terrestrial planet formation. We find that in the realistic accretion model about half of collisions do not lead to accretion. However, the final number, mass, orbital elements, and even growth timescale of planets are barely affected by the accretion condition. For the standard protoplanetary disk model, typically two Earth-sized planets form in the terrestrial planet region over about 10{sup 8} yr in both realistic and perfect accretion models. We also find that for the realistic accretion model, the spin angular velocity is about 30% smaller than that for the perfect accretion model, which is as large as the critical spin angular velocity for rotational instability. The spin angular velocity and obliquity obey Gaussian and isotropic distributions, respectively, independently of the accretion condition.

Kokubo, Eiichiro [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo 181-8588 (Japan); Genda, Hidenori [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Ookayama, Meguro, Tokyo 152-8551 (Japan)], E-mail: kokubo@th.nao.ac.jp, E-mail: genda@geo.titech.ac.jp

2010-05-01

314

Modeling Terrestrial Gamma-Ray Flashes  

NASA Astrophysics Data System (ADS)

Upward positive intra-cloud (IC) lightning may drive the large-scale electric fields inside thunderclouds above the relativistic feedback threshold, causing the production of relativistic runaway electron avalanches (RREAs) to become self-sustaining through the generation of backward propagating runaway positrons and back-scattered x-rays. This causes the number of runaway electrons, and the resulting x-ray and gamma-ray emission, to grow exponentially until ionization causes the electric field to discharge, bringing the field below the relativistic feedback threshold again and causing the number of runaway electrons to decline. A new transport code is presented that models runaway electron avalanche growth along with the positron and x-ray feedback processes. Specifically, the model includes the production, propagation, diffusion and avalanche multiplication of runaway electrons, the production and propagation of x-rays and gamma-rays, and the production, propagation and annihilation of runaway positrons. In the model, the large scale electric fields are calculated self-consistently from the charge motion of the drifting low-energy electrons and ions, produced from the ionization of air by the runaway electrons, including 2 and 3-body electron attachment and recombination. Simulation results will be presented that show that when relativistic feedback is taken into account, bright gamma-ray flashes are a natural consequence of upward +IC lightning propagating in large scale thundercloud fields. Furthermore, these flashes have the same time structures, intensities, current-moments, and energy spectra as the terrestrial gamma-ray flashes (TGFs) measured by the RHESSI and Fermi spacecraft.

Dwyer, J. R.

2011-12-01

315

Black hole evaporation and compact extra dimensions  

SciTech Connect

We study the evaporation of black holes in space-times with extra dimensions of size L by employing the microcanonical picture of Hawking's radiation. We show that the luminosity is greatly damped when the horizon becomes smaller than L and black holes born with an initial size smaller than L are almost stable. This effect is due to the strong dependence of both the occupation number density of Hawking quanta and the greybody factor of a black hole on the dimensionality of space. Although the picture of what happens when the horizon shrinks to a size L is still incomplete, we argue that there might occur an outburst of energy which leaves a quasistable remnant.

Casadio, Roberto; Harms, Benjamin

2001-07-15

316

Electromagnetic Casimir energy with extra dimensions  

SciTech Connect

We calculate the energy-momentum tensor due to electromagnetic vacuum fluctuations between two parallel hyperplanes in more than four dimensions, considering both metallic and MIT boundary conditions. Using the axial gauge, the problem can be mapped upon the corresponding problem with a massless, scalar field satisfying, respectively, Dirichlet or Neumann boundary conditions. The pressure between the plates is constant while the energy density is found to diverge at the boundaries when there are extra dimensions. This can be related to the fact that Maxwell theory is then no longer conformally invariant. A similar behavior is known for the scalar field where a constant energy density consistent with the pressure can be obtained by improving the energy-momentum tensor with the Huggins term. This is not possible for the Maxwell field. However, the change in the energy-momentum tensor with distance between boundaries is finite in all cases.

Alnes, H.; Ravndal, F.; Wehus, I. K.; Olaussen, K. [Department of Physics, University of Oslo, N-0316 Oslo (Norway); Department of Physics, NTNU, N-7491 Trondheim (Norway)

2006-11-15

317

Integrated Estimates of Global Terrestrial Carbon Sequestration  

SciTech Connect

Assessing the contribution of terrestrial carbon sequestration to international climate change mitigation requires integration across scientific and disciplinary boundaries. As part of a scenario analysis for the US Climate Change Technology Program, measurements and geographic data were used to develop terrestrial carbon sequestration estimates for agricultural soil carbon, reforestation and pasture management. These estimates were then applied in the MiniCAM integrated assessment model to evaluate mitigation strategies within policy and technology scenarios aimed at achieving atmospheric CO2 stabilization by 2100. Adoption of terrestrial sequestration practices is based on competition for land and economic markets for carbon. Terrestrial sequestration reach a peak combined rate of 0.5 to 0.7 Gt carbon yr-1 in mid-century with contributions from agricultural soil (0.21 Gt carbon yr-1), reforestation (0.31 Gt carbon yr-1) and pasture (0.15 Gt carbon yr-1). Sequestration rates vary over time period and with different technology and policy scenarios. The combined contribution of terrestrial sequestration over the next century ranges from 31 to 41 GtC. The contribution of terrestrial sequestration to mitigation is highest early in the century, reaching up to 20% of total carbon mitigation. This analysis provides insight into the behavior of terrestrial carbon mitigation options in the presence and absence of climate change mitigation policies.

Thomson, Allison M.; Izaurralde, R Cesar; Smith, Steven J.; Clarke, Leon E.

2008-02-01

318

Periareolar Extra-Glandular Breast Augmentation  

PubMed Central

BACKGROUND Breast augmentation is the most frequent procedure performed according to the 2009 Quick Facts report of the American Society of Plastic Surgeons. This study presents the periareolar extra-glandular breast augmentation. METHODS From 2004 to 2010 among 32 female patients, peri-areolar incision was performed for breast augmentation. Dissection was performed in subcutaneous plane towards the inferior pole to reach the inframammary fold and was continued in the upwards direction in the subglandular plane to create a pocket. Once the implant of desired size was in place, three sutures fixed the inframammary fold. The skin incision was closed using 4-0 non-absorbable suture. RESULTS The mean age of patients was 30.7 years and the average incision length was 5.8 cm. 59.4% of patients had an implant size of more than 305 ml and less than 10% of patients had drains which were removed the next morning. All patients were followed regularly and no case of implant infection or removal was seen and only 2 patients had slight stretched scars. In one patient, the implant was high riding and no case of the capsular contracture was noticed. Changes in sensation were noted in 21.9% patients at 3 month interval which was reduced to 6.3% at 6 months interval. Similarly no case of rippling or other visible deformity was noted. CONCLUSION The extra-glandular periareolar approach for the breast augmentation can be a good option with few side-effects even it is associated with a higher level of surgical expertise. PMID:25489511

Mohmand, Muhammad Humayun; Ahmad, Muhammad

2013-01-01

319

Brane Stabilization and Regionality of Extra Dimensions  

E-print Network

Extra dimensions are a common feature of beyond the Standard Model physics. In a braneworld scenario, local physics on the brane can depend strongly on the brane's location within the bulk. Generically, the relevant properties of the bulk manifold for the physics on/of the brane are neither local nor global, but depend on the structure of finite regions of the bulk, even for locally homogeneous and isotropic bulk geometries. In a recent work, various mechanisms (in a braneworld context) were considered to stabilize the location of a brane within bulk spaces of non-trivial topology. In this work we elaborate on and generalize that work by considering additional bulk and brane dimensionalities as well as different boundary conditions on the bulk scalar field that provides a Casimir force on the brane, providing further insight on this effect. In D=2+1 (D=5+1) we consider both local and global contributions to the effective potential of a 1-brane (4-brane) wrapped around both the 2-dimensional hyperbolic horn and Euclidean cone, which are used as toy models of an extra-dimensional manifold. We calculate the total energy due to brane tension and elastic energy (extrinsic curvature) as well as that due to the Casimir energy of a bulk scalar satisfying both Dirchlet and Neumann boundary conditions on the brane. In some cases stable minima of the potential are found that result from the competition of at least two of the contributions. Generically, any one of these effects may be sufficient when the bulk space has less symmetry than the manifolds considered here. We highlight the importance of the Casimir effect for the purpose of brane stabilization.

David M. Jacobs; Glenn D. Starkman; Andrew J. Tolley

2014-10-19

320

Solar-Terrestrial Weather Relations.  

NASA Astrophysics Data System (ADS)

The factors mitigating against a short term response of tropospheric circulation systems, of the type claimed by Wilcox et al. (1974), to solar activity are reviewed. The dilemma posed by Wilcox's analyses may be resolved by following Hines in making a clear distinction between cause and effect and thereby allowing that the troposphere itself may actively participate in creating the observed signal. A variant of Wilcox's Vorticity Area Index is suggested. This variant allows us to critically examine the conclusions of Williams (1978) and Williams and Gerety (1980) concerning the significance of the correlation claimed by Wilcox et al. Their conclusions are thereby reversed, with the result being a confirmation of the idea introduced by Halevy (1978) concerning the candidacy of baroclinic instability for providing a means by which the troposphere might participate in producing the solar-terrestrial weather correlation. A sequence of simple one-dimensional linear dynamical models are analysed in order to directly test this hypothesis. It is first demonstrated through analysis of the wave mechanics of barotropic instability that such disturbances are not inevitably trapped in the vicinity of the shear maximum. The barotropic problem supports a sequence of long wavelength radiating modes through the mechanism of critical level overreflection. A similar detailed analysis of more complicated one-dimensional baroclinic instability problems establishes a similar modal structure in that the fundamental "Charney" mode is inevitably accompanied in realistic models by a sequence of resonant undertones which are generally referred to as Green modes. If there were a mechanism by which the Green modes could be made growth-rate competitive with the Charney modes then their evolution in the troposphere could be strongly affected by direct solar influence on the upper stratosphere and mesosphere and we would have the basis of an explicit model of the mechanism by which the correlation between solar and terrestrial weather is established. Several attempts to effect such an increase of importance of the Green modes are discussed, no one of which is completely satisfactory but each of which is suggestive of avenues worthy of further investigation.

Halevy, Itamar

321

Solar-terrestrial models and application software  

NASA Technical Reports Server (NTRS)

The empirical models related to solar-terrestrial sciences are listed and described which are available in the form of computer programs. Also included are programs that use one or more of these models for application specific purposes. The entries are grouped according to the region of the solar-terrestrial environment to which they belong and according to the parameter which they describe. Regions considered include the ionosphere, atmosphere, magnetosphere, planets, interplanetary space, and heliosphere. Also provided is the information on the accessibility for solar-terrestrial models to specify the magnetic and solar activity conditions.

Bilitza, Dieter

1990-01-01

322

Solar Terrestrial Physics: Present and Future  

NASA Technical Reports Server (NTRS)

The following topics relating to solar-terrestrial interactions are considered: (1) reconnection of magnetic fields; (2) particle acceleration; (3) solar magnetic flux; (4) magnetohydrodynamic waves and turbulence in the Sun and interplanetary medium; (5) coupling of the solar wind to the magnetosphere; (6) coronal transients; (7) the connection between the magnetosphere and ionosphere; (8) substorms in the magnetosphere; (9) solar flares and the solar terrestrial environment; (10) shock waves in the solar terrestrial environment; (11) plasma transport and convection at high latitudes; and (12) high latitude ionospheric structure.

Butler, D. M. (editor); Papadopoulos, K. (editor)

1984-01-01

323

Where did Terrestrial Life Begin?  

Microsoft Academic Search

DR. MACFIE'S letter (NATURE, January 26, p. 107) accepts the common idea that the surface of the earth was formerly very hot-an assumption which is probably not well founded. If the earth was formed by accumulation of meteoric matter, it began its existence as a cold body the interior of which afterwards became heated by condensation, aided by atomic disintegration,

F. J. Allen

1922-01-01

324

Extra Solar Planetary Imaging Coronagraph and Science Requirements for the James Webb Telescope Observatory  

NASA Technical Reports Server (NTRS)

1) Extra solar planetary imaging coronagraph. Direct detection and characterization of Jovian planets, and other gas giants, in orbit around nearby stars is a necessary precursor to Terrestrial Planet Finder 0 in order to estimate the probability of Terrestrial planets in our stellar neighborhood. Ground based indirect methods are biased towards large close in Jovian planets in solar systems unlikely io harbor Earthlike planets. Thus to estimate the relative abundances of terrestrial planets and to determine optimal observing strategies for TPF a pathfinder mission would be desired. The Extra-Solar Planetary Imaging Coronagraph (EPIC) is such a pathfinder mission. Upto 83 stellar systems are accessible with a 1.5 meter unobscured telescope and coronagraph combination located at the Earth-Sun L2 point. Incorporating radiometric and angular resolution considerations show that Jovians could be directly detected (5 sigma) in the 0.5 - 1.0 micron band outside of an inner working distance of 5/D with integration times of -10 - 100 hours per observation. The primary considerations for a planet imager are optical wavefront quality due to manufacturing, alignment, structural and thermal considerations. pointing stability and control, and manufacturability of coronagraphic masks and stops to increase the planetary-to- stellar contrast and mitigate against straylight. Previously proposed coronagraphic concepts are driven to extreme tolerances. however. we have developed and studied a mission, telescope and coronagraphic detection concept, which is achievable in the time frame of a Discovery class NASA mission. 2) Science requirements for the James Webb Space Telescope observatory. The James Webb Space Observatory (JWST) is an infrared observatory, which will be launched in 201 1 to an orbit at L2. JWST is a segmented, 18 mirror segment telescope with a diameter of 6.5 meters, and a clear aperture of 25 mA2. The telescope is designed to conduct imaging and spectroscopic observations from 0.6-27 microns. The primary mirror find and understand predicted first light objects, observe galaxies back to their earliest precursors so that we can understand their growth and evolution, unravel the birth and early evolution of stars and planetary systems, and study planetary systems and the origins of life. In this paper we discuss the science goals for JWST in the context of the performance requirements they levy on the observatory.

Clampin, Mark

2004-01-01

325

Body Parts  

NSDL National Science Digital Library

In this online game, learners test their knowledge of human anatomy. Learners are presented a mystery image of a body part and use their mouse to select the proper body part from a full size anatomical model (known as "Jerome"). Learners try to match all 10 body parts correctly. Use this activity to review human anatomy and/or introduce learners to the use of anatomical models.

National Museum of American History, Smithsonian Institution

2012-06-26

326

Black Body  

Microsoft Academic Search

A black body was first defined by Gustav R. Kirchhoff (1824–87) in 1859 as an object that absorbs all radiation falling upon\\u000a it. Such a conception of an ideal black body was crucial for understanding heat radiation and its laws. Since a completely\\u000a black body does not exist in nature, it had to be constructed. Kirchhoff had already suggested that

Dieter Hoffmann

327

Perfusion Imaging in Pusher Syndrome to Investigate the Neural Substrates Involved in Controlling Upright Body Position  

Microsoft Academic Search

Brain damage may induce a dysfunction of upright body position termed “pusher syndrome”. Patients with such disorder suffer from an alteration of their sense of body verticality. They experience their body as oriented upright when actually tilted nearly 20 degrees to the ipsilesional side. Pusher syndrome typically is associated with posterior thalamic stroke; less frequently with extra-thalamic lesions. This argued

Luca Francesco Ticini; Uwe Klose; Thomas Nägele; Hans-Otto Karnath; Christoph Kleinschnitz

2009-01-01

328

Body Piercing  

PubMed Central

OBJECTIVE To review the current information on medical complications, psychological implications, and legislative issues related to body piercing, a largely unregulated industry in the United States. METHODS We conducted a MEDLINE search of English language articles from 1966 until May 1998 using the search terms “body piercing” and “ear piercing.” Bibliographies of these references were reviewed for additional citations. We also conducted an Internet search for “body piercing” on the World Wide Web. MAIN RESULTS: In this manuscript, we review the available body piercing literature. We conclude that body piercing is an increasingly common practice in the United States, that this practice carries substantial risk of morbidity, and that most body piercing in the United States is being performed by unlicensed, unregulated individuals. Primary care physicians are seeing growing numbers of patients with body pierces. Practitioners must be able to recognize, treat, and counsel patients on body piercing complications and be alert to associated psychological conditions in patients who undergo body piercing. PMID:10354260

Koenig, Laura M; Carnes, Molly

1999-01-01

329

Terrestrial Energy Storage SPS Systems  

NASA Technical Reports Server (NTRS)

Terrestrial energy storage systems for the SSP system were evaluated that could maintain the 1.2 GW power level during periods of brief outages from the solar powered satellite (SPS). Short-term outages of ten minutes and long-term outages up to four hours have been identified as "typical" cases where the ground-based energy storage system would be required to supply power to the grid. These brief interruptions in transmission could result from performing maintenance on the solar power satellite or from safety considerations necessitating the power beam be turned off. For example, one situation would be to allow for the safe passage of airplanes through the space occupied by the beam. Under these conditions, the energy storage system needs to be capable of storing 200 MW-hrs and 4.8 GW-hrs, respectively. The types of energy storage systems to be considered include compressed air energy storage, inertial energy storage, electrochemical energy storage, superconducting magnetic energy storage, and pumped hydro energy storage. For each of these technologies, the state-of-the-art in terms of energy and power densities were identified as well as the potential for scaling to the size systems required by the SSP system. Other issues addressed included the performance, life expectancy, cost, and necessary infrastructure and site locations for the various storage technologies.

Brandhorst, Henry W., Jr.

1998-01-01

330

Steroidal saponins from Tribulus terrestris.  

PubMed

Sixteen steroidal saponins, including seven previously unreported compounds, were isolated from Tribulus terrestris. The structures of the saponins were established using 1D and 2D NMR spectroscopy, mass spectrometry, and chemical methods. They were identified as: 26-O-?-d-glucopyranosyl-(25R)-furost-4-en-2?,3?,22?,26-tetrol-12-one (terrestrinin C), 26-O-?-d-glucopyranosyl-(25R)-furost-4-en-22?,26-diol-3,12-dione (terrestrinin D), 26-O-?-d-glucopyranosyl-(25S)-furost-4-en-22?,26-diol-3,6,12-trione (terrestrinin E), 26-O-?-d-glucopyranosyl-(25R)-5?-furostan-3?,22?,26-triol-12-one (terrestrinin F), 26-O-?-d-glucopyranosyl-(25R)-furost-4-en-12?,22?,26-triol-3-one (terrestrinin G), 26-O-?-d-glucopyranosyl-(1?6)-?-d-glucopyranosyl-(25R)-furost-4-en-22?,26-diol-3,12-dione (terrestrinin H), and 24-O-?-d-glucopyranosyl-(25S)-5?-spirostan-3?,24?-diol-12-one-3-O-?-d-glucopyranosyl-(1?4)-?-d-galactopyranoside (terrestrinin I). The isolated compounds were evaluated for their platelet aggregation activities. Three of the known saponins exhibited strong effects on the induction of platelet aggregation. PMID:25172515

Kang, Li-Ping; Wu, Ke-Lei; Yu, He-Shui; Pang, Xu; Liu, Jie; Han, Li-Feng; Zhang, Jie; Zhao, Yang; Xiong, Cheng-Qi; Song, Xin-Bo; Liu, Chao; Cong, Yu-Wen; Ma, Bai-Ping

2014-11-01

331

Bibliography of terrestrial impact structures  

NASA Technical Reports Server (NTRS)

This bibliography lists 105 terrestrial impact structures, of which 12 are proven structures, that is, structures associated with meteorites, and 93 are probable. Of the 93 probable structures, 18 are known to contain rocks with meteoritic components or to be enriched in meteoritic signature-elements, both of which enhance their probability of having originated by impact. Many of the structures investigated in the USSR to date are subsurface features that are completely or partly buried by sedimentary rocks. At least 16 buried impact structures have already been identified in North America and Europe. No proven nor probable submarine impact structure rising above the ocean floor is presently known; none has been found in Antarctica or Greenland. An attempt has been made to cite for each impact structure all literature published prior to mid-1983. The structures are presented in alphabetical order by continent, and their geographic distribution is indicated on a sketch map of each continent in which they occur. They are also listed tables in: (1) alphabetical order, (2) order of increasing latitude, (3) order of decreasing diameter, and (4) order of increasing geologic age.

Grolier, M. J.

1985-01-01

332

Terrestrial Mobile Mapping: photogrammetric simulator  

NASA Astrophysics Data System (ADS)

Nowadays many types of sensors are used for terrestrial mobile mapping (TMM): IMU, odometers, GNSS, cameras, etc., and it is essential to understand how these sensors can improve the solution in terms of precision, accuracy and reliability. TMM issues are characterized by many variables: vehicle trajectory, the height of the buildings and the distance between them, traffic conditions, the presence or absence of trees, the level of illumination, etc. The aim of this study is to determine how photogrammetric measurements can improve the quality of TMM solution at least concerning magnitude and error propagation when there is no GNSS signal (for example in an urban canyon). Another purpose of the study was to determine the most suitable design project for a specific relief in order to obtain the best possible photogrammetric results. By analyzing the error propagation in the various components of relative orientation along the trajectory and considering a sequence of images characterized by an overlap varying between 60 to 90% and the same number of tie points, results were obtained which confirmed the reliability of the data produced by the simulator. These results are shown in this paper.

Taglioretti, C.; Manzino, A. M.

2014-08-01

333

Terrestrial Planet Finder: science overview  

NASA Technical Reports Server (NTRS)

The Terrestrial Planet Finder (TPF) seeks to revolutionize our understanding of humanity's place in the universe - by searching for Earth-like planets using reflected light, or thermal emission in the mid-infrared. Direct detection implies that TPF must separate planet light from glare of the nearby star, a technical challenge which has only in recent years been recognized as surmountable. TPF will obtain a low-resolution spectra of each planets it detects, providing some of its basic physical characteristics and its main atmospheric constituents, thereby allowing us to assess the likelihood that habitable conditions exist there. NASA has decided the scientific importance of this research is so high that TPF will be pursued as two complementary space observatories: a visible-light coronagraph and a mid-infrared formation flying interferometer. The combination of spectra from both wavebands is much more valuable than either taken separately, and it will allow a much fuller understanding of the wide diversity of planetary atmospheres that may be expected to exist. Measurements across a broad wavelength range will yield not only physical properties such as size and albedo, but will also serve as the foundations of a reliable and robust assessment of habitability and the presence of life.

Unwin, Stephen C.; Beichman, C. A.

2004-01-01

334

Terrestrial cooling and solar variability  

NASA Technical Reports Server (NTRS)

Observational evidence from surface temperature records is presented and discussed which suggests a significant cooling trend over the Northern Hemisphere from 1940 to the present. This cooling trend is associated with an increase of the latitudinal gradient of temperature and the lapse rate, as predicted by climate models with decreased solar input and feedback mechanisms. Evidence suggests that four of these 80- to 100-year cycles of global surface temperature fluctuation may have occurred, and in succession, from 1600 to the present. Interpretation of sunspot activity were used to infer a direct thermal response of terrestrial temperature to solar variability on the time scale of the Gleissberg cycle (90 years, an amplitude of the 11-year cycles). A physical link between the sunspot activity and the solar parameter is hypothesized. Observations of sensible heat flux by stationary planetary waves and transient eddies, as well as general circulation modeling results of these processes, were examined from the viewpoint of the hypothesis of cooling due to reduced insolation.

Agee, E. M.

1982-01-01

335

Tightly integrated sensor-based terrestrial LiDAR georeferencing  

NASA Astrophysics Data System (ADS)

Georeferencing of terrestrial LiDAR scanning data is typically performed by using scanner target points occupying control points in the project area. This necessitates intensive field labor and extra, often cumbersome equipment. A method for georeferencing scan data using two GPS antennas firmly mounted on the optical head of a LiDAR scanner has been developed. By adding a dual GPS antenna apparatus to the scanner setup, thereby supplanting the use of multiple ground control points scattered throughout the project, we mitigate not only the problems associated with georeferencing but also induce a more efficient set up procedure while maintaining a practical level of precision. This study is an extension of the dual GPS antenna method by creating a process for a simultaneous network adjustment of multiple scanner stations. By exploiting additional sensor information from a scanner-mounted camera and point cloud matching techniques, an integrated adjustment of observations from this sensor suite is developed. Further, the technique is tested on two distinct data sets. The testing consists of comparison with conventional techniques and different combinations of the novel, more autonomous methods. Analysis includes the investigation of precision, accuracy, efficiency, and conditioning under different configurations of the system. The test results indicate that centimeter-level accuracy at a scanner-point distance of 40 meters can be achieved using only imagery and scanner-mounted GPS data, and that under certain circumstances, the autonomous methods were able to approach the same level of precision as the conventional data-driven method.

Wilkinson, Benjamin E.

336

Imaging exo-solar planetary systems with Terrestrial Planet Finder  

NASA Astrophysics Data System (ADS)

The concept of building a space based telescope capable of directly imaging extra-solar planetary systems has been in existence for more than a decade. While the basic ideas of how such an instrument might work have already been discussed in the literature, specific details of the design have not been addressed that will enable a telescope of this class to be functionally realized. A straw man configuration of the instrument is examined here for its ability to acquire data of sufficient informational content and quality to produce images and spectra of distant planetary systems and to find what technical problems arise from analyzing the interferograms it delivers. Computer programs that simulate the signals expected to be produced by a structurally connected instrument (SCI) version of Terrestrial Planet Finder (TPF) and reconstruct images from those signals will be presented along with programs that extract planetary parameters. An abbreviated radiometric performance analysis will also be provided that will assist astronomers in designing an appropriate mission.

Eatchel, Andrew Lynn

337

20 CFR 332.4 - Restrictions in extra service.  

Code of Federal Regulations, 2012 CFR

...be considered to exist in rotating extra board, pool, or chain gang service when there is in effect an arrangement between the...arrangement is such that an employee in extra board, pool, or chain gang service gets the equivalent of full-time work, his lack...

2012-04-01

338

20 CFR 332.4 - Restrictions in extra service.  

Code of Federal Regulations, 2010 CFR

...be considered to exist in rotating extra board, pool, or chain gang service when there is in effect an arrangement between the...arrangement is such that an employee in extra board, pool, or chain gang service gets the equivalent of full-time work, his lack...

2010-04-01

339

20 CFR 332.4 - Restrictions in extra service.  

Code of Federal Regulations, 2011 CFR

...be considered to exist in rotating extra board, pool, or chain gang service when there is in effect an arrangement between the...arrangement is such that an employee in extra board, pool, or chain gang service gets the equivalent of full-time work, his lack...

2011-04-01

340

20 CFR 332.4 - Restrictions in extra service.  

Code of Federal Regulations, 2014 CFR

...be considered to exist in rotating extra board, pool, or chain gang service when there is in effect an arrangement between the...arrangement is such that an employee in extra board, pool, or chain gang service gets the equivalent of full-time work, his lack...

2014-04-01

341

20 CFR 332.4 - Restrictions in extra service.  

Code of Federal Regulations, 2013 CFR

...be considered to exist in rotating extra board, pool, or chain gang service when there is in effect an arrangement between the...arrangement is such that an employee in extra board, pool, or chain gang service gets the equivalent of full-time work, his lack...

2013-04-01

342

19 CFR 151.64 - Extra copy of entry summary.  

Code of Federal Regulations, 2012 CFR

...CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.64 Extra copy of entry summary. One extra copy of the entry summary covering wool or hair subject to duty at a rate per clean kilogram shall be filed in...

2012-04-01

343

19 CFR 151.64 - Extra copy of entry summary.  

Code of Federal Regulations, 2014 CFR

...CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.64 Extra copy of entry summary. One extra copy of the entry summary covering wool or hair subject to duty at a rate per clean kilogram shall be filed in...

2014-04-01

344

19 CFR 151.64 - Extra copy of entry summary.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.64 Extra copy of entry summary. One extra copy of the entry summary covering wool or hair subject to duty at a rate per clean kilogram shall be filed in...

2013-04-01

345

7 CFR 51.300 - U.S. Extra Fancy.  

Code of Federal Regulations, 2013 CFR

... United States Standards for Grades of Apples Grades § 51.300 U.S. Extra... “U.S. Extra Fancy” consists of apples of one variety (except when more...visible water core, and broken skins. The apples are also free from injury caused...

2013-01-01

346

7 CFR 51.300 - U.S. Extra Fancy.  

Code of Federal Regulations, 2011 CFR

... United States Standards for Grades of Apples Grades § 51.300 U.S. Extra... “U.S. Extra Fancy” consists of apples of one variety (except when more...visible water core, and broken skins. The apples are also free from injury caused...

2011-01-01

347

7 CFR 51.300 - U.S. Extra Fancy.  

Code of Federal Regulations, 2014 CFR

... United States Standards for Grades of Apples Grades § 51.300 U.S. Extra... “U.S. Extra Fancy” consists of apples of one variety (except when more...visible water core, and broken skins. The apples are also free from injury caused...

2014-01-01

348

7 CFR 51.300 - U.S. Extra Fancy.  

Code of Federal Regulations, 2010 CFR

... United States Standards for Grades of Apples Grades § 51.300 U.S. Extra... “U.S. Extra Fancy” consists of apples of one variety (except when more...visible water core, and broken skins. The apples are also free from injury caused...

2010-01-01

349

7 CFR 51.300 - U.S. Extra Fancy.  

Code of Federal Regulations, 2012 CFR

... United States Standards for Grades of Apples Grades § 51.300 U.S. Extra... “U.S. Extra Fancy” consists of apples of one variety (except when more...visible water core, and broken skins. The apples are also free from injury caused...

2012-01-01

350

19 CFR 151.64 - Extra copy of entry summary.  

Code of Federal Regulations, 2010 CFR

...CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.64 Extra copy of entry summary. One extra copy of the entry summary covering wool or hair subject to duty at a rate per clean kilogram shall be filed in...

2010-04-01

351

19 CFR 151.64 - Extra copy of entry summary.  

Code of Federal Regulations, 2011 CFR

...CONTINUED) EXAMINATION, SAMPLING, AND TESTING OF MERCHANDISE Wool and Hair § 151.64 Extra copy of entry summary. One extra copy of the entry summary covering wool or hair subject to duty at a rate per clean kilogram shall be filed in...

2011-04-01

352

Quantifying inbreeding avoidance through extra-pair reproduction.  

PubMed

Extra-pair reproduction is widely hypothesized to allow females to avoid inbreeding with related socially paired males. Consequently, numerous field studies have tested the key predictions that extra-pair offspring are less inbred than females' alternative within-pair offspring, and that the probability of extra-pair reproduction increases with a female's relatedness to her socially paired male. However, such studies rarely measure inbreeding or relatedness sufficiently precisely to detect subtle effects, or consider biases stemming from failure to observe inbred offspring that die during early development. Analyses of multigenerational song sparrow (Melospiza melodia) pedigree data showed that most females had opportunity to increase or decrease the coefficient of inbreeding of their offspring through extra-pair reproduction with neighboring males. In practice, observed extra-pair offspring had lower inbreeding coefficients than females' within-pair offspring on average, while the probability of extra-pair reproduction increased substantially with the coefficient of kinship between a female and her socially paired male. However, simulations showed that such effects could simply reflect bias stemming from inbreeding depression in early offspring survival. The null hypothesis that extra-pair reproduction is random with respect to kinship therefore cannot be definitively rejected in song sparrows, and existing general evidence that females avoid inbreeding through extra-pair reproduction requires reevaluation given such biases. PMID:25346331

Reid, Jane M; Arcese, Peter; Keller, Lukas F; Germain, Ryan R; Duthie, A Bradley; Losdat, Sylvain; Wolak, Matthew E; Nietlisbach, Pirmin

2015-01-01

353

Quantifying inbreeding avoidance through extra-pair reproduction  

PubMed Central

Extra-pair reproduction is widely hypothesized to allow females to avoid inbreeding with related socially paired males. Consequently, numerous field studies have tested the key predictions that extra-pair offspring are less inbred than females’ alternative within-pair offspring, and that the probability of extra-pair reproduction increases with a female's relatedness to her socially paired male. However, such studies rarely measure inbreeding or relatedness sufficiently precisely to detect subtle effects, or consider biases stemming from failure to observe inbred offspring that die during early development. Analyses of multigenerational song sparrow (Melospiza melodia) pedigree data showed that most females had opportunity to increase or decrease the coefficient of inbreeding of their offspring through extra-pair reproduction with neighboring males. In practice, observed extra-pair offspring had lower inbreeding coefficients than females’ within-pair offspring on average, while the probability of extra-pair reproduction increased substantially with the coefficient of kinship between a female and her socially paired male. However, simulations showed that such effects could simply reflect bias stemming from inbreeding depression in early offspring survival. The null hypothesis that extra-pair reproduction is random with respect to kinship therefore cannot be definitively rejected in song sparrows, and existing general evidence that females avoid inbreeding through extra-pair reproduction requires reevaluation given such biases. PMID:25346331

Reid, Jane M; Arcese, Peter; Keller, Lukas F; Germain, Ryan R; Duthie, A Bradley; Losdat, Sylvain; Wolak, Matthew E; Nietlisbach, Pirmin

2015-01-01

354

The Geology of the Terrestrial Planets  

NASA Technical Reports Server (NTRS)

The geologic history of the terrestrial planets is outlined in light of recent exploration and the revolution in geologic thinking. Among the topics considered are planet formation; planetary craters, basins, and general surface characteristics; tectonics; planetary atmospheres; and volcanism.

Carr, M. H. (editor); Saunders, R. S.; Strom, R. G.; Wilhelms, D. E.

1984-01-01

355

The development of early terrestrial ecosystems  

E-print Network

In this review of terrestrialization by plants and animals in the early Phanerozoic, the classical idea of a major mid-Palaeozoic event is discarded in favour of gradual colonization over a long time period. Four phases ...

Selden, Paul A.; Edwards, Dianne

1993-01-01

356

Data Base of Terrestrial Impact Structures  

NSDL National Science Digital Library

Database of Terrestrial Impact Structures leads to Natural Resources Canada's interactive global database of impact structures, complete with photographs and summary information. For those interested in learning more about Impact Craters, this is a fine starting point.

1997-01-01

357

DEVELOPMENT OF SCALING CRITERIA FOR TERRESTRIAL MICROCOSMS  

EPA Science Inventory

Theoretical developments based on heat and moisture transfer in soil lead to dimensionless numbers that describe important processes taking place in a terrestrial microcosm. These numbers provide preliminary scientific criteria for scaling the results from microcosms both as a me...

358

AIR POLLUTION EFFECTS ON TERRESTRIAL ECOSYSTEMS  

EPA Science Inventory

This report presents information on the effects of ozone, nitrogen oxides, sulfur oxides, particulate matter, and acidic disposition on terrestrial ecosystems. A brief explanation of ecosystem dynamics is presented to provide a framework for discussion of air pollutant effects. D...

359

Recommended architectures for the Terrestrial Planet Finder  

NASA Technical Reports Server (NTRS)

The primary conclusion from an intensive, two year period of study is that with suitable technology investment, starting now, a mission to detect terrestrial planets around nearby stars could be launched within a decade.

Beichman, C.

2004-01-01

360

Space Vehicle Terrestrial Environment Design Requirements Guidelines  

NASA Technical Reports Server (NTRS)

The terrestrial environment is an important driver of space vehicle structural, control, and thermal system design. NASA is currently in the process of producing an update to an earlier Terrestrial Environment Guidelines for Aerospace Vehicle Design and Development Handbook. This paper addresses the contents of this updated handbook, with special emphasis on new material being included in the areas of atmospheric thermodynamic models, wind dynamics, atmospheric composition, atmospheric electricity, cloud phenomena, atmospheric extremes, and sea state. In addition, the respective engineering design elements are discussed relative to terrestrial environment inputs that require consideration. Specific lessons learned that have contributed to the advancements made in the application and awareness of terrestrial environment inputs for aerospace engineering applications are presented.

Johnson, Dale L.; Keller, Vernon W.; Vaughan, William W.

2006-01-01

361

Global Change and the Terrestrial Biosphere  

SciTech Connect

Terrestrial ecosystems sustain life on Earth through the production of food, fuel, fiber, clean air, and naturally purified water. But how will agriculture and ecosystems be affected by global change? Rogers describes the impact of projected climate change on the terrestrial biosphere and explains why plants are not just passive respondents to global change, but play an important role in determining the rate of change.

Alistair Rogers

2009-04-22

362

Update on terrestrial ages of Antarctic meteorites  

SciTech Connect

Terrestrial ages of Antarctic meteorites are one of the few parameters that will help us to understand the meteorite concentration mechanism on blue-ice fields. Traditionally, terrestrial ages were determined on the basis of {sup 36}Cl in the metal phase, which has an uncertainty of about 70 ky. For young meteorites (< 40 ky), the terrestrial age is usually and most accurately determined using {sup 14}C in the stone phase. In recent years two methods have been developed which are independent of shielding effects, the {sup 10}Be-{sup 36}Cl/{sup 10}Be method and the {sup 41}Ca/{sup 36}Cl method. These methods have reduced the typical uncertainties in terrestrial ages by a factor of 2, to about 30 ky. The {sup 10}Be-{sup 36}Cl/{sup 10}Be method is quite dependent on the exposure age, which is unknown for most Antarctic meteorites. The authors therefore also attempt to use the relation between {sup 26}Al and {sup 36}Cl/{sup 26}Al to derive a terrestrial age less dependent on the exposure age. The authors have measured the concentrations of cosmogenic {sup 10}Be, {sup 26}Al and {sup 36}Cl in the metal phase of {approximately} 70 Antarctic meteorites, from more than 10 different ice-fields, including many new ones. They then discuss the trends in terrestrial ages of meteorites from different ice-fields.

Welten, K C; Nishiizumi, K; Caffee, M W

2000-01-14

363

Possible climates on terrestrial exoplanets.  

PubMed

What kind of environment may exist on terrestrial planets around other stars? In spite of the lack of direct observations, it may not be premature to speculate on exoplanetary climates, for instance, to optimize future telescopic observations or to assess the probability of habitable worlds. To begin with, climate primarily depends on (i) the atmospheric composition and the volatile inventory; (ii) the incident stellar flux; and (iii) the tidal evolution of the planetary spin, which can notably lock a planet with a permanent night side. The atmospheric composition and mass depends on complex processes, which are difficult to model: origins of volatiles, atmospheric escape, geochemistry, photochemistry, etc. We discuss physical constraints, which can help us to speculate on the possible type of atmosphere, depending on the planet size, its final distance for its star and the star type. Assuming that the atmosphere is known, the possible climates can be explored using global climate models analogous to the ones developed to simulate the Earth as well as the other telluric atmospheres in the solar system. Our experience with Mars, Titan and Venus suggests that realistic climate simulators can be developed by combining components, such as a 'dynamical core', a radiative transfer solver, a parametrization of subgrid-scale turbulence and convection, a thermal ground model and a volatile phase change code. On this basis, we can aspire to build reliable climate predictors for exoplanets. However, whatever the accuracy of the models, predicting the actual climate regime on a specific planet will remain challenging because climate systems are affected by strong positive feedbacks. They can drive planets with very similar forcing and volatile inventory to completely different states. For instance, the coupling among temperature, volatile phase changes and radiative properties results in instabilities, such as runaway glaciations and runaway greenhouse effect. PMID:24664919

Forget, F; Leconte, J

2014-04-28

364

Phosphatidylcholine composition of pulmonary surfactant from terrestrial and marine diving mammals.  

PubMed

Marine mammals are repeatedly exposed to elevated extra-thoracic pressure and alveolar collapse during diving and readily experience alveolar expansion upon inhalation - a unique capability as compared to terrestrial mammals. How marine mammal lungs overcome the challenges of frequent alveolar collapse and recruitment remains unknown. Recent studies indicate that pinniped lung surfactant has more anti-adhesive components compared to terrestrial mammals, which would aid in alveolar opening. However, pulmonary surfactant composition has not yet been investigated in odontocetes, whose physiology and diving behavior differ from pinnipeds. The aim of this study was to investigate the phosphatidylcholine (PC) composition of lung surfactants from various marine mammals and compare these to a terrestrial mammal. We found an increase in anti-adhesive PC species in harp seal (Pagophilus groenlandicus) and California sea lion (Zalophus californianus) compared to dog (Canus lupus familiaris), as well as an increase in the fluidizing PCs 16:0/14:0 and 16:0/16:1 in pinnipeds compared to odontocetes. The harbor porpoise (a representative of the odontocetes) did not have higher levels of fluidizing PCs compared to dog. Our preliminary results support previous findings that pinnipeds may have adapted unique surfactant compositions that allow them to dive at high pressures for extended periods without adverse effects. Future studies will need to investigate the differences in other surfactant components to fully assess the surfactant composition in odontocetes. PMID:25812797

Gutierrez, Danielle B; Fahlman, Andreas; Gardner, Manuela; Kleinhenz, Danielle; Piscitelli, Marina; Raverty, Stephen; Haulena, Martin; Zimba, Paul V

2015-06-01

365

DNA Barcoding Reveals Cryptic Diversity in Lumbricus terrestris L., 1758 (Clitellata): Resurrection of L. herculeus (Savigny, 1826)  

PubMed Central

The widely studied and invasive earthworm, Lumbricus terrestris L., 1758 has been the subject of nomenclatural debate for many years. However these disputes were not based on suspicions of heterogeneity, but rather on the descriptions and nomenclatural acts associated with the species name. Large numbers of DNA barcode sequences of the cytochrome oxidase I obtained for nominal L. terrestris and six congeneric species reveal that there are two distinct lineages within nominal L. terrestris. One of those lineages contains the Swedish population from which the name-bearing specimen of L. terrestris was obtained. The other contains the population from which the syntype series of Enterion herculeum Savigny, 1826 was collected. In both cases modern and old representatives yielded barcode sequences allowing us to clearly establish that these are two distinct species, as different from one another as any other pair of congeners in our data set. The two are morphologically indistinguishable, except by overlapping size-related characters. We have designated a new neotype for L. terrestris. The newly designated neotype and a syntype of L. herculeus yielded DNA adequate for sequencing part of the cytochrome oxidase I gene (COI). The sequence data make possible the objective determination of the identities of earthworms morphologically identical to L. terrestris and L. herculeus, regardless of body size and segment number. Past work on nominal L. terrestris could have been on either or both species, although L. herculeus has yet to be found outside of Europe. PMID:21206917

James, Samuel W.; Porco, David; Decaëns, Thibaud; Richard, Benoit; Rougerie, Rodolphe; Erséus, Christer

2010-01-01

366

Derivation of transfer parameters for use within the ERICA Tool and the default concentration ratios for terrestrial biota.  

PubMed

An ability to predict radionuclide activity concentrations in biota is a requirement of any method assessing the exposure of biota to ionising radiation. Within the ERICA Tool fresh weight whole-body activity concentrations in organisms are estimated using concentration ratios (the ratio of the activity concentration in the organism to the activity concentration in an environmental media). This paper describes the methodology used to derive the default terrestrial ecosystem concentration ratio database available within the ERICA Tool and provides details of the provenance of each value for terrestrial reference organisms. As the ERICA Tool considers 13 terrestrial reference organisms and the radioisotopes of 31 elements, a total of 403 concentration ratios were required for terrestrial reference organisms. Of these, 129 could be derived from literature review. The approaches taken for selecting the remaining values are described. These included, for example, assuming values for similar reference organisms and/or biogeochemically similar elements, and various simple modelling approaches. PMID:18406022

Beresford, N A; Barnett, C L; Howard, B J; Scott, W A; Brown, J E; Copplestone, D

2008-09-01

367

Higgs production in a warped extra dimension  

NASA Astrophysics Data System (ADS)

Measurements of the Higgs-boson production cross section at the LHC are an important tool for studying electroweak symmetry breaking at the quantum level, since the main production mechanism gg ? h is loop-suppressed in the Standard Model (SM). Higgs production in extra-dimensional extensions of the SM is sensitive to the Kaluza-Klein (KK) excitations of the quarks, which can be exchanged as virtual particles in the loop. In the context of the minimal Randall-Sundrum (RS) model with bulk fields and a brane-localized Higgs sector, we derive closed analytical expressions for the gluon-gluon fusion process, finding that the effect of the infinite tower of virtual KK states can be described in terms of a simple function of the fundamental (5D) Yukawa matrices. Given a specific RS model, this will allow one to easily constrain the parameter space, once a Higgs signal has been established. We explain that discrepancies between existing calculations of Higgs production in RS models are related to the non-commutativity of two limits: taking the number of KK states to infinity and removing the regulator on the Higgs-boson profile, which is required in an intermediate step to make the relevant overlap integrals well defined. Even though the one-loop gg ? h amplitude is finite in RS scenarios with a brane-localized Higgs sector, it is important to introduce a consistent ultraviolet regulator in order to obtain the correct result.

Carena, Marcela; Casagrande, Sandro; Goertz, Florian; Haisch, Ulrich; Neubert, Matthias

2012-08-01

368

LHC Signals from Warped Extra Dimensions  

SciTech Connect

We study production of Kaluza-Klein gluons (KKG) at the Large Hadron Collider (LHC) in the framework of a warped extra dimension with the Standard Model (SM) fields propagating in the bulk. We show that the detection of KK gluon is challenging since its production is suppressed by small couplings to the proton's constituents. Moreover, the KK gluon decaysmostly to top pairs due to an enhanced coupling and hence is broad. Nevertheless, we demonstrate that for MKKG<~;; 4 TeV, 100 fb-1 of data at the LHC can provide discovery of the KK gluon. We utilize a sizeable left-right polarization asymmetry from the KK gluon resonance to maximize the signal significance, and we explore the novel feature of extremely highly energetic"top-jets." We briefly discuss how the detection of electroweak gauge KK states (Z/W) faces a similar challenge since their leptonic decays ("golden" modes) are suppressed. Our analysis suggests that other frameworks, for example little Higgs, which rely on UV completion via strong dynamics might face similar challenges, namely (1) Suppressed production rates for the new particles (such as Z'), due to their"lightfermion-phobic" nature, and (2) Difficulties in detection since the new particles are broad and decay predominantly to third generation quarks and longitudinal gauge bosons.

Agashe, K.; Belyaev, A.; Krupovnickas, T.; Perez, G.; Virzi, J.

2006-12-06

369

Syncyclons or solitonic signals from extra dimensions  

SciTech Connect

This paper reports that in theories where space-time is a direct product of Minkowski space (M{sup 4}) and a d-dimensional compact space (K{sup d}), there can exist topological solitons that simultaneously wind around R{sup 3} (or R{sup 2} or R{sup 1}) in M{sup 4} and the compact dimensions. A paradigmatic nongravitational example of such co-winding solitons is furnished by Yang-Mills theory defined on M{sup 4} {times} S{sup 1}. Point-like, string-like and sheet-like solitons can be identified by transcribing and generalizing the procedure used to construct the periodic instanton (caloron) solutions. Asymptotically the classical point-like objects have non-Abelian magnetic dipole fields together with a non-Abelian scalar potential while the color electric charge is zero. However quantization of collective coordinates associated with zero modes and coupling to fermions can radically change these quantum numbers due to fermion number fractionalization and its non-Abelian generalization. Interpreting the YM group as color (or the electroweak SU(2) group) and assuming that an extra circular dimension exists thus implies the existence of topologically stable solitonic objects which carry baryon (Lepton) number and a mass O(1/g{sup 2} R), where R is the radius of the compact dimension.

Aulakh, C.S. (Inst. of Physics, Sachivalya Marg, Bhubhaneshwar (IN))

1992-07-30

370

Extra dimensions and atomic transition frequencies  

E-print Network

New unification theories predict Large Extra Dimensions (LEDs). If that is the case, gravity would be stronger at short ranges than what Newtonian gravity predicts. LEDs could also have effects at atomic level. In this paper we propose a new method to constrain the size of gravity-only LEDs by analyzing how these LEDs modify the energy of the atomic transitions 1s-2s and 2s-2p (Lamb shift), for the particular case of the hydrogen and muonium atoms. We estimate these effects by using Bethe's non-relativistic treatment of Lamb shift. For the particular case of three LEDs, which may be a candidate to explain the interaction mechanism of dark matter particles, we have found that current knowledge in atomic spectroscopy could constrain their sizes to be less than 10 * 10^(-6) m. Although our contributions do not reach the sensitivity given by SN1987a, they are still slightly better than recent constraints given by Inverse Square Law tests of Eot-Wash group at Washington University, which gave R3 < 36.6 * 10^(-6) m.

Li zhigang; Wei-Tou Ni; Antonio Pulido Paton

2007-06-27

371

Gravitational instantons, extra dimensions and form fields  

E-print Network

A broad class of higher dimensional instanton solutions are found for a theory which contains gravity, a scalar field and antisymmetric tensor fields of arbitrary rank. The metric used, a warp product of an arbitrary number of any compact Einstein manifolds, includes many of great interest in particle physics and cosmology. For example 4D FRW universes with additional dimensions compactified on a Calabi-Yau three fold, a torus, a compact hyperbolic manifold or a sphere are all included. It is shown that the solution of this form which dominates the Hartle Hawking path integral is always a higher dimensional generalisation of a Hawking Turok instanton when the potential of the scalar field is such that these instantons can exist. On continuation to Lorentzian signature such instantons give rise to a spacetime in which all of the spatial dimensions are of equal size and where the spatial topology is that of a sphere. The extra dimensions are thus not hidden. In the case where the potential for the scalar field is generated solely by a dilatonic coupling to the form fields we find no integrable instantons at all. In particular we find no integrable solutions of the type under consideration for the supergravity theories which are the low energy effective field theories of superstrings.

J. A. Gray; E. J. Copeland

2001-02-15

372

STS-109 Extra Vehicular Activity (EVA)  

NASA Technical Reports Server (NTRS)

Inside the Space Shuttle Columbia's cabin, astronaut Nancy J. Currie, mission specialist, controlled the Remote Manipulator System (RMS) on the crew cabin's aft flight deck to assist fellow astronauts during the STS-109 mission Extra Vehicular Activities (EVA). The RMS was used to capture the telescope and secure it into Columbia's cargo bay. The Space Shuttle Columbia STS-109 mission lifted off March 1, 2002 with goals of repairing and upgrading the Hubble Space Telescope (HST). The Marshall Space Flight Center in Huntsville, Alabama had the responsibility for the design, development, and construction of the HST, which is the most powerful and sophisticated telescope ever built. STS-109 upgrades to the HST included: replacement of the solar array panels; replacement of the power control unit (PCU); replacement of the Faint Object Camera (FOC) with a new advanced camera for Surveys (ACS); and installation of the experimental cooling system for the Hubble's Near-Infrared Camera and Multi-object Spectrometer (NICMOS), which had been dormant since January 1999 when its original coolant ran out. Lasting 10 days, 22 hours, and 11 minutes, the STS-109 mission was the 108th flight overall in NASA's Space Shuttle Program.

2002-01-01

373

Influence of Tribulus terrestris on testicular enzyme in fresh water ornamental fish Poecilia latipinna.  

PubMed

The influence of Tribulus terrestris on the activities of testicular enzyme in Poecilia latipinna was assessed in lieu of reproductive manipulation. Different concentrations of (100, 150, 200, 250, and 300 mg) Tribulus terrestris extract and of a control were tested for testicular activity of enzymes in Poecilia latipinna for 2 months. The testis and liver were homogenized separately in 0.1 mol/l potassium phosphate buffer (0.1 mol/l, pH 7.2). The crude homogenate was centrifuged, and supernatant obtained was used as an enzyme extract for determination of activities. The activities of testicular functional enzyme ALP, ACP, SDH, LDH, and G6PDH levels were changed to different extent in treated groups compared with that of the control. The total body weight and testis weight were increased with the Tribulus terrestris-treated fish (Poecilia latipinna). These results suggest that Tribulus terrestris induced the testicular enzyme activity that may aid in the male reproductive functions. It is discernible from the present study that Tribulus terrestris has the inducing effect on reproductive system of Poecilia latipinna. PMID:21424528

Kavitha, P; Subramanian, P

2011-12-01

374

Lunar and terrestrial planet formation in the Grand Tack scenario  

NASA Astrophysics Data System (ADS)

We present conclusions from a large number of N-body simulations of the giant impact phase of terrestrial planet formation. We focus on new results obtained from the recently proposed Grand Tack model, which couples the gas-driven migration of giant planets to the accretion of the terrestrial planets. The giant impact phase follows the oligarchic growth phase, which builds a bi-modal mass distribution within the disc of embryos and planetesimals. By varying the ratio of the total mass in the embryo population to the total mass in the planetesimal population and the mass of the individual embryos, we explore how different disc conditions control the final planets. The total mass ratio of embryos to planetesimals controls the timing of the last giant (Moon forming) impact and its violence. The initial embryo mass sets the size of the lunar impactor and the growth rate of Mars. After comparing our simulated outcomes with the actual orbits of the terrestrial planets (angular momentum deficit, mass concentration) and taking into account independent geochemical constraints on the mass accreted by the Earth after the Moon forming event and on the timescale for the growth of Mars, we conclude that the protoplanetary disc at the beginning of the giant impact phase must have had most of its mass in Mars-sized embryos and only a small fraction of the total disc mass in the planetesimal population. From this, we infer that the Moon forming event occurred between ˜60 and ˜130 My after the formation of the first solids, and was caused most likely by an object with a mass similar to that of Mars.

Jacobson, S. A.; Morbidelli, A.

2014-09-01

375

Lunar and terrestrial planet formation in the Grand Tack scenario.  

PubMed

We present conclusions from a large number of N-body simulations of the giant impact phase of terrestrial planet formation. We focus on new results obtained from the recently proposed Grand Tack model, which couples the gas-driven migration of giant planets to the accretion of the terrestrial planets. The giant impact phase follows the oligarchic growth phase, which builds a bi-modal mass distribution within the disc of embryos and planetesimals. By varying the ratio of the total mass in the embryo population to the total mass in the planetesimal population and the mass of the individual embryos, we explore how different disc conditions control the final planets. The total mass ratio of embryos to planetesimals controls the timing of the last giant (Moon-forming) impact and its violence. The initial embryo mass sets the size of the lunar impactor and the growth rate of Mars. After comparing our simulated outcomes with the actual orbits of the terrestrial planets (angular momentum deficit, mass concentration) and taking into account independent geochemical constraints on the mass accreted by the Earth after the Moon-forming event and on the time scale for the growth of Mars, we conclude that the protoplanetary disc at the beginning of the giant impact phase must have had most of its mass in Mars-sized embryos and only a small fraction of the total disc mass in the planetesimal population. From this, we infer that the Moon-forming event occurred between approximately 60 and approximately 130?Myr after the formation of the first solids and was caused most likely by an object with a mass similar to that of Mars. PMID:25114304

Jacobson, S A; Morbidelli, A

2014-09-13

376

Visible Body  

NSDL National Science Digital Library

The human body is an intricate, and often mysterious, place. With today's technology, however, many websites and apps provide entry into this fascinating world. Visible Body is one of the more compelling avenues for exploration. While there are paid products on the site, some of the content is available at no charge. Visitors can look over the Human Anatomy Atlas, which contains a range of visualizations that allow users to explore body systems in exquisite detail. For a small fee, users may access the other specific areas of the site, which include Digestive Anatomy, Respiratory Anatomy, and Reproductive & Urinary Anatomy.

377

Terrestrialization, Miniaturization and Rates of Diversification in African Puddle Frogs (Anura: Phrynobatrachidae)  

PubMed Central

Terrestrialization, the evolution of non-aquatic oviposition, and miniaturization, the evolution of tiny adult body size, are recurring trends in amphibian evolution, but the relationships among the traits that characterize these phenomena are not well understood. Furthermore, these traits have been identified as possible “key innovations” that are predicted to increase rates of speciation in those lineages in which they evolve. We examine terrestrialization and miniaturization in sub-Saharan puddle frogs (Phrynobatrachidae) in a phylogenetic context to investigate the relationship between adaptation and diversification through time. We use relative dating techniques to ascertain if character trait shifts are associated with increased diversification rates, and we evaluate the likelihood that a single temporal event can explain the evolution of those traits. Results indicate alternate reproductive modes evolved independently in Phrynobatrachus at least seven times, including terrestrial deposition of eggs and terrestrial, non-feeding larvae. These shifts towards alternate reproductive modes are not linked to a common temporal event. Contrary to the “key innovations” hypothesis, clades that exhibit alternate reproductive modes have lower diversification rates than those that deposit eggs aquatically. Adult habitat, pedal webbing and body size have no effect on diversification rates. Though these traits putatively identified as key innovations for Phrynobatrachus do not seem to be associated with increased speciation rates, they may still provide opportunities to extend into new niches, thus increasing overall diversity. PMID:22509392

Zimkus, Breda M.; Lawson, Lucinda; Loader, Simon P.; Hanken, James

2012-01-01

378

Trace element and isotope geochemistry of Cretaceous-Tertiary boundary sediments: identification of extra-terrestrial and volcanic components  

NASA Technical Reports Server (NTRS)

Trace element and stable isotope analyses were performed on a series of sediment samples crossing the Cretaceous-Tertiary (K-T) boundary from critical sections at Aumaya and Sopelano, Spain. The aim is to possibly distinguish extraterrestrial vs. volcanic or authigenic concentration of platinum group and other elements in K-T boundary transitional sediments. These sediments also have been shown to contain evidence for step-wise extinction of several groups of marine invertebrates, associated with negative oxygen and carbon isotope excursions occurring during the last million years of the Cretaceous. These isotope excursions have been interpreted to indicate major changes in ocean thermal regime, circulation, and ecosystems that may be related to multiple events during latest Cretaceous time. Results to date on the petrographic and geochemical analyses of the Late Cretaceous and Early Paleocene sediments indicate that diagenesis has obviously affected the trace element geochemistry and stable isotope compositions at Zumaya. Mineralogical and geochemical analysis of K-T boundary sediments at Zumaya suggest that a substantial fraction of anomalous trace elements in the boundary marl are present in specific mineral phases. Platinum and nickel grains perhaps represent the first direct evidence of siderophile-rich minerals at the boundary. The presence of spinels and Ni-rich particles as inclusions in aluminosilicate spherules from Zumaya suggests an original, non-diagenetic origin for the spherules. Similar spherules from southern Spain (Caravaca), show a strong marine authigenic overprint. This research represents a new approach in trying to directly identify the sedimentary mineral components that are responsible for the trace element concentrations associated with the K-T boundary.

Margolis, S. V.; Doehne, E. F.

1988-01-01

379

The decoding problem: do we need to search for extra terrestrial intelligence in order to search for extraterrestrial intelligence?  

Microsoft Academic Search

There is a widespread and perhaps uncritically accepted assumption on the part of SETI researchers and popularizers that we could tell what an ETI might be trying to tell us. We raise difficulties for this assumption. If the assumption is abandoned, a lot follows. We might even be able to argue, in a novel way, that SETI will be utterly

Neil W. Tennant

1993-01-01

380

Distinct Roles for Hematopoietic and Extra-Hematopoietic Sphingosine Kinase-1 in Inflammatory Bowel Disease  

PubMed Central

Sphingosine kinase 1 (SK1), one of two SK enzymes, is highly regulated and has been shown to act as a focal point for the action of many growth factors and cytokines. SK1 leads to generation of sphingosine-1-phosphate (S1P) and potentially the activation of S1P receptors to mediate biologic effects. Our previous studies implicated SK1/S1P in the regulation of inflammatory processes, specifically in inflammatory bowel disease (IBD). These studies were conducted using a total body knockout mouse for SK1 and were unable to determine the source of SK1/S1P (hematopoietic or extra-hematopoietic) involved in the inflammatory responses. Therefore, bone marrow transplants were performed with wild-type (WT) and SK1-/- mice and colitis induced with dextran sulfate sodium (DSS). Irrespective of the source of SK1/S1P, bone marrow or tissue, DSS induced colitis in all mice; however, mice lacking SK1 in both hematopoietic and extra-hematopoietic compartments exhibited decreased crypt damage. Systemic inflammation was assessed, and mice with WT bone marrow demonstrated significant neutrophilia in response to DSS. In the local inflammatory response, mice lacking SK1/S1P in either bone marrow or tissue exhibited decreased induction of cytokines and less activation of STAT3 (signal transducer and activator of transcription 3). Interestingly, we determined that extra-hematopoietic SK1 is necessary for the induction of cyclooxygenase 2 (COX2) in colon epithelium in response to DSS-induced colitis. Taken together our data suggest that hematopoietic-derived SK1/S1P regulates specific aspects of the systemic inflammatory response, while extra-hematopoietic SK1 in the colon epithelium is necessary for the autocrine induction of COX2 in DSS-induced colitis. PMID:25460165

Snider, Ashley J.; Ali, Wahida H.; Sticca, Jonathan A.; Coant, Nicolas; Ghaleb, Amr M.; Kawamori, Toshihiko; Yang, Vincent W.; Hannun, Yusuf A.; Obeid, Lina M.

2014-01-01

381

Terrestrial teleconnections link global rivers  

NASA Astrophysics Data System (ADS)

We present analyses of river discharge data from across the world, which we used to identify links between annual river flow regimes across different continents. Our hypothesis was that, as atmospheric processes are subject to large-scale teleconnection patterns, and because these atmospheric processes are inherently linked to precipitation regimes across the world, there should be identifiable links between river flow regimes driven by these atmospheric processes. We used discharge data from the Global Runoff Data Centre (GRDC) to identify cross-correlations (and accounted for serial dependence) between 23 of the world's largest river basins where overlapping data were available over a period of 12 years or more: two in South America; five in Africa; one in Australasia; five in North America and ten in Eurasia. The selected river basins drain approximately a third of the Earth's landmass at their furthest downstream gauging station. Where significant cross-correlations were found, we compared these to known patterns associated with the ENSO and NAO teleconnections. In total, 85 of the 253 possible correlations were deemed significant at p<0.05, this reduced to 36 at p<0.01 and 21 at p<0.001. Of the significant correlations (p<0.05), 22 were classified as strong (r ?× 0.5), 45 as moderate (×0.5< r ?×0.25) and 18 as weak (×0.25< r >0). We compared these significant cross-correlations with known atmospheric teleconnection patterns, and while these were consistent for the majority of cases, we found a number of significant correlations that are inconsistent with the anticipated effects of known atmospheric teleconnections. Our results provide new insight into the inter-continental links between global river systems and the way in which these are controlled by large-scale atmospheric processes. We suggest this may be useful for global industries, such as insurers or aid agencies, who seek to understand correlations between the magnitudes of extreme events across different regions of the world. For the former, this may enable more efficient management of global liabilities, for the latter it may enable better logistical planning of disaster relief requirements. Aside from these practical applications, the results also suggest teleconnections exist between terrestrial, as well as ocean and atmospheric water systems.

O'Loughlin, F.; Howden, N. J.; Woods, R. A.; Bates, P. D.

2013-12-01

382

Groundwater and Terrestrial Water Storage  

NASA Technical Reports Server (NTRS)

Most people think of groundwater as a resource, but it is also a useful indicator of climate variability and human impacts on the environment. Groundwater storage varies slowly relative to other non-frozen components of the water cycle, encapsulating long period variations and trends in surface meteorology. On seasonal to interannual timescales, groundwater is as dynamic as soil moisture, and it has been shown that groundwater storage changes have contributed to sea level variations. Groundwater monitoring well measurements are too sporadic and poorly assembled outside of the United States and a few other nations to permit direct global assessment of groundwater variability. However, observational estimates of terrestrial water storage (TWS) variations from the GRACE satellites largely represent groundwater storage variations on an interannual basis, save for high latitude/altitude (dominated by snow and ice) and wet tropical (surface water) regions. A figure maps changes in mean annual TWS from 2009 to 2010, based on GRACE, reflecting hydroclimatic conditions in 2010. Severe droughts impacted Russia and the Amazon, and drier than normal weather also affected the Indochinese peninsula, parts of central and southern Africa, and western Australia. Groundwater depletion continued in northern India, while heavy rains in California helped to replenish aquifers that have been depleted by drought and withdrawals for irrigation, though they are still below normal levels. Droughts in northern Argentina and western China similarly abated. Wet weather raised aquifer levels broadly across western Europe. Rains in eastern Australia caused flooding to the north and helped to mitigate a decade long drought in the south. Significant reductions in TWS seen in the coast of Alaska and the Patagonian Andes represent ongoing glacier melt, not groundwater depletion. Figures plot time series of zonal mean and global GRACE derived non-seasonal TWS anomalies (deviation from the mean of each month of the year) excluding Greenland and Antarctica. The two figures show that 2010 was the driest year since 2003. The drought in the Amazon was largely responsible, but an excess of water in 2009 seems to have buffered that drought to some extent. The drying trend in the 25-55 deg S zone is a combination of Patagonian glacier melt and drought in parts of Australia.

Rodell, Matthew; Chambers, Don P.; Famiglietti, James S.

2011-01-01

383

Cytomorphologic spectrum in aspirates of extra-adrenal paraganglioma  

PubMed Central

Background: Paraganglioma is a rare tumor arising from clusters of neuroendocrine cells in association with sympathetic and parasympathetic nervous system. It poses a diagnostic challenge because of its widespread anatomic distribution, subtle clinical manifestations, and a variety of morphologic patterns. Aim: The aim of this study is to have an insight into the diverse morphologic spectrum of extra-adrenal paraganglioma (EAP). Materials and Methods: A retrospective analysis of seven cytologically diagnosed cases of EAP over a period of 10 years was performed. There were five superficial swellings and two deep seated retroperitoneal masses. The superficial swellings were aspirated directly, and the retroperitoneal masses were aspirated under ultrasound guidance using 22-gauge lumbar puncture needle fitted to a 10 mL syringe. Smears were reviewed for cellularity, pattern, cell shape, cytoplasm, nuclear features, and background. Results: The age of patients ranged from 25 to 75 years; four patients were males and three were females. Sites involved were carotid body region (four cases), para-pharyngeal space (one case) and para-aortic region (two cases). All the cases yielded hemorrhagic material on fine-needle aspiration. Smears showed scattered and clusters of cells and loosely cohesive acini of tumor cells. Cells were round to polygonal with pleomorphic nuclei, granular chromatin, inconspicuous nucleoli, and moderate to abundant cytoplasm containing fine pink granules and vacuolations. The cases were confirmed on radiology and histopathology. Conclusion: The cytologic features in EAP along with pertinent clinicoradiologic findings help in making an accurate preoperative diagnosis of an otherwise rare tumor. PMID:25210234

Handa, Uma; Kundu, Reetu; Mohan, Harsh

2014-01-01

384

7 CFR 457.105 - Extra long staple cotton crop insurance provisions.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Extra long staple cotton crop insurance provisions. 457.105...REGULATIONS § 457.105 Extra long staple cotton crop insurance provisions. The extra long staple cotton crop insurance provisions for the...

2013-01-01

385

Body Swatter  

NSDL National Science Digital Library

Students work in cooperative groups to research and write questions for an active game designed to review the major organs of the systems of the human body (digestive, respiratory, circulatory, and excretory system).

2013-02-15

386

Body Systems  

NSDL National Science Digital Library

What are the parts and functions of the different systems in the body? Circulatory System Watch the Circulatory System and the Heart video. Complete one of the Circulatory System quizzes. Excretory System Label the parts of the excretory system. Respiratory System Quiz Complete respiratory system quiz to review parts. Skeletal System Label each part of the skeletal system. Vocabulary Review Change the settings to only include body system terms and play Hangman to review new vocabulary. ...

2011-11-02

387

Canonical Extra Mixing in Low-Mass Red Giants  

NASA Astrophysics Data System (ADS)

We have used the latest observational data on the evolutionary variations of the surface chemical composition in low-mass metal-poor stars, both in the field and in globular clusters, to constrain the basic properties of extra mixing in upper red giant branch (RGB) stars. Two different models of extra mixing have been incorporated into a stellar evolution code: a parametrical diffusion model and a model with rotation-induced turbulent diffusion. Application of the first model to the interpretation of the observed variations of the surface abundances of Li, C, and N and of the isotopic ratio 12C/13C in field stars has revealed that, for the majority of upper RGB stars, the depth and rate of extra mixing do not appear to vary appreciably from star to star. Furthermore, comparisons of our calculations with the results obtained by other authors show that at least the extra mixing depth does not seem to depend strongly on metallicity. Therefore, we propose to call this universal nonconvective mixing process ``canonical extra mixing.'' We also put forward the hypothesis that some of the upper RGB stars may be experiencing ``enhanced extra mixing,'' which is much faster (by a factor of ~100) and somewhat deeper than canonical extra mixing. This could explain the phenomenon of Li-rich giants. Enhanced extra mixing could also contribute to the O-Na and Mg-Al anticorrelations that are seen in some globular cluster red giants. A possible mechanism of extra mixing in upper RGB stars may be turbulent diffusion or/and meridional circulation induced by rotation. In this case, enhanced extra mixing requires rotational velocities that are ~10 times as fast as those that are sufficient for the occurrence of canonical extra mixing. Observations do not exclude this possibility because (1) the dispersion in the surface rotational velocities of field Li-rich giants span a range of a factor of ~10 and (2) the extremely fast rotation of blue horizontal branch stars in globular clusters may require that their RGB precursors had been spun up appreciably by an external source. Star-to-star abundance variations in globular clusters may well have been produced as the result of both evolutionary and primordial processes. In the primordial scenario, the nuclearly processed material that is accreted by low-mass main-sequence stars may have originated primarily in earlier generations of massive asymptotic giant branch stars that had undergone hot bottom burning of their envelopes and partly in mass-losing upper RGB stars that had been just a bit more massive than the present-day main-sequence turnoff stars and had experienced extra mixing in the past.

Denissenkov, Pavel A.; VandenBerg, Don A.

2003-08-01

388

Female house wrens (Troglodytes aedon) increase the size, but not immunocompetence, of their offspring through extra-pair mating.  

PubMed

House wrens are typically socially monogamous, but frequently engage in extra-pair matings leading to multisired broods. Because females do not appear to acquire direct material benefits from their extra-pair mates, we tested the hypothesis that female house wrens derive indirect genetic benefits, such as enhanced immunocompetence (cutaneous immune activity, humoral immunity, and plasma bactericidal activity) and condition (size and haematoserological traits) for their offspring, by mating polyandrously. We predicted that extra-pair young (EPY) should show greater immune responsiveness and better body condition than their within-pair maternal half-siblings (WPY). Contrary to our prediction, WPY had higher cutaneous immune activity than their EPY brood-mates in two of three years, and EPY and WPY did not differ in measures of innate and humoral immunity. WPY also had higher albumin to gamma-globulin ratios than EPY; however, they were not in better condition based on other measures. EPY had consistently longer tarsi (a measure of long-bone size) than their WPY half-siblings, suggesting that females engage in extra-pair copulations with larger males. The benefits of large structural size in the study population is unknown, but based on evidence from other passerines, we suggest that structural size may be an important fitness-related trait in house wrens. We conclude that our results are not consistent with the hypothesis that females gain immune-related benefits for their offspring by engaging in extra-pair matings. Further study of the fitness consequences of differences in tarsus length is needed to determine whether females acquire size-related benefits for their offspring from extra-pair mates. PMID:18662223

Forsman, Anna M; Vogel, Laura A; Sakaluk, Scott K; Johnson, Bonnie G; Masters, Brian S; Johnson, L Scott; Thompson, Charles F

2008-08-01

389

Girls and war: an extra vulnerability.  

PubMed

It is no longer possible to consider the raping of girls as an isolated atrocity of war. In Uganda, guerrilla forces have kidnapped 6000-10,000 children and have forced the "most desirable" girls to become "wives" of warlords. Girls who manage to escape are deeply traumatized and suffer ill health as well as possible social ostracism. In refugee camps, recognition that adolescent girls face special risks of rape and of engaging in the informal prostitution that may expose them to HIV/AIDS has led to the introduction of new measures to increase female security. Families in refugee camps in Burundi and Somalia protect female honor by submitting their daughters to very early marriage, which also abuses the girls' rights. Girls conscripted to military groups are forced to transport materials, cook, or help loot villages. In conditions of war, even girls who remain at home protected by their families must assume extra responsibilities, especially if men go off to fight leaving women with the agricultural and livestock burdens. Girls will be the first children withdrawn from school to help keep the household afloat. Girls and women are also expected to tend those wounded by the very war that destroys the health care services that are vital to meet women's reproductive needs. Efforts are being made to identify rape as a specific war crime, and these efforts should be extended to the kidnapping and forced recruitment of children into combat roles. Moral codes must be reestablished, even if they are only nominal at present. PMID:12321764

Black, M

1998-01-01

390

Error bounds from extra precise iterative refinement  

SciTech Connect

We present the design and testing of an algorithm for iterative refinement of the solution of linear equations, where the residual is computed with extra precision. This algorithm was originally proposed in the 1960s [6, 22] as a means to compute very accurate solutions to all but the most ill-conditioned linear systems of equations. However two obstacles have until now prevented its adoption in standard subroutine libraries like LAPACK: (1) There was no standard way to access the higher precision arithmetic needed to compute residuals, and (2) it was unclear how to compute a reliable error bound for the computed solution. The completion of the new BLAS Technical Forum Standard [5] has recently removed the first obstacle. To overcome the second obstacle, we show how a single application of iterative refinement can be used to compute an error bound in any norm at small cost, and use this to compute both an error bound in the usual infinity norm, and a componentwise relative error bound. We report extensive test results on over 6.2 million matrices of dimension 5, 10, 100, and 1000. As long as a normwise (resp. componentwise) condition number computed by the algorithm is less than 1/max{l_brace}10,{radical}n{r_brace} {var_epsilon}{sub w}, the computed normwise (resp. componentwise) error bound is at most 2 max{l_brace}10,{radical}n{r_brace} {center_dot} {var_epsilon}{sub w}, and indeed bounds the true error. Here, n is the matrix dimension and w is single precision roundoff error. For worse conditioned problems, we get similarly small correct error bounds in over 89.4% of cases.

Demmel, James; Hida, Yozo; Kahan, William; Li, Xiaoye S.; Mukherjee, Soni; Riedy, E. Jason

2005-02-07

391

Lorentz Violation in Warped Extra Dimensions  

SciTech Connect

Higher dimensional theories which address some of the problematic issues of the Standard Model(SM) naturally involve some form of D = 4 + n-dimensional Lorentz invariance violation (LIV). In such models the fundamental physics which leads to, e.g., field localization, orbifolding, the existence of brane terms and the compactification process all can introduce LIV in the higher dimensional theory while still preserving 4-d Lorentz invariance. In this paper, attempting to capture some of this physics, we extend our previous analysis of LIV in 5-d UED-type models to those with 5- d warped extra dimensions. To be specific, we employ the 5-d analog of the SM Extension of Kostelecky et al. which incorporates a complete set of operators arising from spontaneous LIV. We show that while the response of the bulk scalar, fermion and gauge fields to the addition of LIV operators in warped models is qualitatively similar to what happens in the flat 5-d UED case, the gravity sector of these models reacts very differently than in flat space. Specifically, we show that LIV in this warped case leads to a non-zero bulk mass for the 5-d graviton and so the would-be zero mode, which we identify as the usual 4-d graviton, must necessarily become massive. The origin of this mass term is the simultaneous existence of the constant non-zero AdS{sub 5} curvature and the loss of general co-ordinate invariance via LIV in the 5-d theory. Thus warped 5-d models with LIV in the gravity sector are not phenomenologically viable.

Rizzo, Thomas G.; /SLAC

2011-08-11

392

Predictability of the terrestrial carbon cycle.  

PubMed

Terrestrial ecosystems sequester roughly 30% of anthropogenic carbon emission. However this estimate has not been directly deduced from studies of terrestrial ecosystems themselves, but inferred from atmospheric and oceanic data. This raises a question: to what extent is the terrestrial carbon cycle intrinsically predictable? In this paper, we investigated fundamental properties of the terrestrial carbon cycle, examined its intrinsic predictability, and proposed a suite of future research directions to improve empirical understanding and model predictive ability. Specifically, we isolated endogenous internal processes of the terrestrial carbon cycle from exogenous forcing variables. The internal processes share five fundamental properties (i.e., compartmentalization, carbon input through photosynthesis, partitioning among pools, donor pool-dominant transfers, and the first-order decay) among all types of ecosystems on the Earth. The five properties together result in an emergent constraint on predictability of various carbon cycle components in response to five classes of exogenous forcing. Future observational and experimental research should be focused on those less predictive components while modeling research needs to improve model predictive ability for those highly predictive components. We argue that an understanding of predictability should provide guidance on future observational, experimental and modeling research. PMID:25327167

Luo, Yiqi; Keenan, Trevor F; Smith, Matthew

2015-05-01

393

Terrestrial Planet Formation Around Close Binary Stars  

NASA Technical Reports Server (NTRS)

Most stars reside in multiple star systems; however, virtually all models of planetary growth have assumed an isolated single star. Numerical simulations of the collapse of molecular cloud cores to form binary stars suggest that disks will form within such systems. Observations indirectly suggest disk material around one or both components within young binary star systems. If planets form at the right places within such circumstellar disks, they can remain in stable orbits within the binary star systems for eons. We are simulating the late stages of growth of terrestrial planets around close binary stars, using a new, ultrafast, symplectic integrator that we have developed for this purpose. The sum of the masses of the two stars is one solar mass, and the initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and in the Alpha Centauri wide binary star system. Giant planets &are included in the simulations, as they are in most simulations of the late stages of terrestrial planet accumulation in our Solar System. When the stars travel on a circular orbit with semimajor axis of up to 0.1 AU about their mutual center of mass, the planetary embryos grow into a system of terrestrial planets that is statistically identical to those formed about single stars, but a larger semimajor axis and/or a significantly eccentric binary orbit can lead to significantly more dynamically hot terrestrial planet systems.

Lissauer, Jack J.; Quintana, Elisa V.

2003-01-01

394

BOOK REVIEW: Black Holes, Cosmology and Extra Dimensions Black Holes, Cosmology and Extra Dimensions  

NASA Astrophysics Data System (ADS)

The book Black holes, Cosmology and Extra Dimensions written by Kirill A Bronnikov and Sergey G Rubin has been published recently by World Scientific Publishing Company. The authors are well known experts in gravity and cosmology. The book is a monograph, a considerable part of which is based on the original work of the authors. Their original point of view on some of the problems makes the book quite interesting, covering a variety of important topics of the modern theory of gravity, astrophysics and cosmology. It consists of 11 chapters which are organized in three parts. The book starts with an introduction, where the authors briefly discuss the main ideas of General Relativity, giving some historical remarks on its development and application to cosmology, and mentioning some more recent subjects such as brane worlds, f(R)-theories and gravity in higher dimensions. Part I of the book is called 'Gravity'. Chapters two and three are devoted to the Einstein equations and their spherical symmetric black hole solutions. This material is quite standard and can be found in practically any book on General Relativity. A brief summary of the Kerr metric and black hole thermodynamics are given in chapter four. The main part of this chapter is devoted to spherically symmetric black holes in non-Einstein gravity (with scalar and phantom fields), black holes with regular interior, and black holes in brane worlds. Chapters five and six are mainly dedicated to wormholes and the problem of their stability. Part II (Cosmology) starts with discussion of the Friedmann-Robertson-Walker and de Sitter solutions of the Einstein equations and their properties. It follows by describing a `big picture' of the modern cosmology (inflation, post-inflationary reheating, the radiation-dominated and matter-dominated states, and modern stage of the (secondary) inflation). The authors explain how the inflation models allow one to solve many of the long-standing problems of cosmology, such as flatness of the Universe, the horizon problem and isotropy of cosmological microwave background. All this material is covered in chapter seven. Chapter eight contains brief discussion of several popular inflation models. Chapter nine is devoted to the problem of the large-scale structure formation from initial quantum vacuum fluctuation during the inflation and the spectrum of the density fluctuations. It also contains remarks on the baryonic asymmetry of the Universe, baryogenesis and primordial black holes. Part III covers the material on extra dimensions. It describes how Einstein gravity is modified in the presence of one or more additional spatial dimensions and how these extra dimensions are compactified in the Kaluza-Klein scheme. The authors also discuss how extra dimensions may affect low energy physics. They present examples of higher-dimensional generalizations of the gravity with higher-in-curvature corrections and discuss a possible mechanism of self-stabilization of an extra space. A considerable part of the chapter 10 is devoted to cosmological models with extra dimensions. In particular, the authors discuss how extra dimensions can modify 'standard' inflation models. At the end of this chapter they make several remarks on a possible relation of the value of fundamental constants in our universe with the existence of extra dimensions. Finally, in chapter 11 they demonstrate that several observable properties of the Universe are closely related with the special value of the fundamental physical constants and their fine tuning. They give interesting examples of such fine tuning and summarize many other cases. The book ends with discussion of a so-called 'cascade birth of universes in multidimensional spaces' model, proposed by one of the authors. As is evident from this brief summary of topics presented in the book, many interesting areas of modern gravity and cosmology are covered. However, since the subject is so wide, this inevitably implies that the selection of the topics and level of their presentation in many cases reflects the authors' own pre

Frolov, Valeri P.

2013-10-01

395

Global calibration of terrestrial reference cells and errors involved in using different irradiance monitoring techniques  

NASA Technical Reports Server (NTRS)

The feasibility of global calibration of terrestrial reference cells is discussed. A simple, accurate 'secondary' calibration technique based on ratios of test to reference cell currents measured in natural sunlight is described. Different techniques for monitoring incident irradiance during solar cell performance measurements are also examined and assessed, including the techniques of black-body detectors, calibrated reference cells, and the convolution of spectral response with solar irradiance.

Curtis, H. B.

1980-01-01

396

Adrenal and Extra-adrenal Myelolipomas - A Comparative Case Report  

PubMed Central

Myelolipoma is an uncommon benign tumour composed of mature fat tissue and haematopoietic elements and is most commonly found in the adrenal gland. We report a case, which was discovered incidentally on chest X-ray, of a rare occurrence of multifocal extra-adrenal myelolipoma in the thoracic paravertebral region. This was further investigated with multi-detector computed tomography and magnetic resonance imaging. The presumed diagnosis, of extra-adrenal myelolipoma, was histologically confirmed via tissue sample obtained by computed tomography guided biopsy. We compare the adrenal and extra-adrenal entities from the perspective of published literature and also review the cases, published in Pubmed, of extra-adrenal myelolipomas in order to summarize the different locations of this lesion. PMID:24967008

Hakim, Arsany; Rozeik, Christoph

2014-01-01

397

Is dark matter an extra-dimensional effect?  

E-print Network

We investigate the possibility that the observed behavior of test particles outside galaxies, which is usually explained by assuming the presence of dark matter, is the result of the dynamical evolution of particles in higher dimensional space-times. Hence, dark matter may be a direct consequence of the presence of an extra force, generated by the presence of extra-dimensions, which modifies the dynamic law of motion, but does not change the intrinsic properties of the particles, like, for example, the mass (inertia). We discuss in some detail several possible particular forms for the extra force, and the acceleration law of the particles is derived. Therefore, the constancy of the galactic rotation curves may be considered as an empirical evidence for the existence of the extra dimensions.

M. E. Kahil; T. Harko

2009-03-26

398

7. LESLIE WICKMAN, EVA (EXTRA VEHICULAR ACTIVITIES) SPECIALIST, IN SPACE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. LESLIE WICKMAN, EVA (EXTRA VEHICULAR ACTIVITIES) SPECIALIST, IN SPACE SUIT AFTER TESTING IN NEUTRAL BUOYANCY TANK. AVERAGE COST OF SUIT IS $1,000,000. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

399

Water on Small Solar System Bodies  

Microsoft Academic Search

\\u000a When examining the outer parts of the solar system water becomes more and more abundant. The water reservoir on the Erath\\u000a and other terrestrial planets might have been supplied by the impact of these objects in the heavy bombardment phase of the\\u000a early solar system evolution. Water on small solar system bodies such as asteroids, comets, objects in the Kuiper

Arnold Hanslmeier

400

Terrestrial impact melt rocks and glasses  

NASA Astrophysics Data System (ADS)

The effects of meteorite and comet impact on Earth are rock brecciation, the formation of shock metamorphic features, rock melting, and the formation of impact structures, i.e. simple craters, complex craters, and multi-ring basins. Large events, such as the 65-Ma Chicxulub impact, are believed to have had catastrophic environmental effects that profoundly influenced the development of life on Earth. In this review, an attempt is made to summarize some of the voluminous literature on impact melting, one important aspect of planetary impact, provide some comments on this process, and to make suggestions for future research. The products of impact melting are glasses, impact melt rocks, and pseudotachylites. Our treatise deals mainly with the geological setting, petrography, and major-element chemistry of melt rocks and glasses. Impact glasses, in several petrographic aspects, are similar to volcanic glasses, but they are associated with shock metamorphosed mineral and rock fragments and, in places, with siderophile element anomalies suggestive of meteoritic contamination. They are found in allogenic breccia deposits within (fall-back 'suevite') and outside (fall-out 'suevite') impact craters and, as spherules, in distal ejecta. Large events, such as the K/T boundary Chicxulub impact, are responsible for the formation of worldwide ejecta horizons which are associated with siderophile element anomalies and shock metamorphosed mineral and rock debris. Impact glasses have a bulk chemical composition that is homogeneous but exemptions to this rule are common. On a microscopic scale, however, impact glasses are commonly strikingly heterogeneous. Tektites are glasses ejected from craters over large distances. They are characterized by very low water and volatile contents and element abundances and ratios that are evidence that tektites formed by melting of upper crustal, sedimentary rocks. Four tektite strewn-fields are known, three of which can be tied to specific impact craters. Impact melt rocks form sheets, lenses, and dike-like bodies within or beneath allogenic fallback breccia deposits in the impact crater and possibly on crater terraces and flanks. Dikes of impact melt rocks also intrude the rocks of the crater floor. They commonly contain shock metamorphosed target rock and mineral fragments in various stages of assimilation and are glassy or fine- to coarse-grained. Chemically, they are strikingly homogeneous, but as with impact glasses, exemptions to this rule do exist. Large and thick melt bodies, such as the Sudbury Igneous Complex (SIC), are differentiated or may represent a combination of impact melt rocks sensu-strictu and impact-triggered, deep-crustal melts. A concerted, multidisciplinary approach to future research on impact melting and on other aspects of meteorite and comet impact is advocated. Impact models are models only and uncritical reliance on their validity will not lead to a better understanding of impact processes—especially of melting, excavation, and deposition of allogenic breccias and the spatial position of breccias in relation to sheets and lenses of melt rocks within the crater. Impact-triggered pressure-release melting of target rocks beneath the excavation cavity may be responsible for the existence of melt rocks beneath the impact melt rocks sensu-strictu. This controversial idea needs to be tested by a re-evaluation of existing data and models, be they based on field or laboratory research. Only a relatively small number of terrestrial impact structures has been investigated in sufficient detail as it relates to geological and geophysical mapping. In this review, we summarize observations made on impact melt rocks and impact glasses in a number of North American (Brent, Haughton, Manicouagan, New Quebec, Sudbury, Wanapitei, all in Canada), Asian (Popigai, Russia; Zhamanshin, Kazakhstan), two South African structures (Morokweng and Vredefort), the Henbury crater field of Australia, and one European crater (Ries, Germany). Our tables listing major-element chemical compositions of impact

Dressler, B. O.; Reimold, W. U.

2001-12-01

401

Comparative planetology: Significance for terrestrial geology  

NASA Technical Reports Server (NTRS)

The crustal evolution of the terrestrial planets increase in complexity and duration with increasing size and mass of the planet. The lunar and mercurian surfaces are largely the result of intense, post-differentiation impact bombardment and subsequent volcanic filling of major impact basins. Mars, being larger, has evolved further: crustal uplifts, rifting, and shield volcanoes have begun to modify its largely Moon-like surface. The Earth is the large end-number of this sequence, where modern plate tectonic processes have erased the earlier lunar and martian type of surfaces. Fundamental problems of the origin of terrestrial continents, ocean basins, and plate tectonics are now addressed within the context of the evolutionary pattern of the terrestrial planets.

Frey, H. V.; Lowman, P. D., R.

1978-01-01

402

Planetary geology and terrestrial analogs in Asia  

NASA Astrophysics Data System (ADS)

2011 PERC Planetary Geology Field Symposium;Kitakyushu City, Japan, 5-6 November 2011 In spite of the extremely diverse geological settings that exist in Asia, relatively little attention has previously been paid to this region in terms of terrestrial analog studies for planetary application. Asia is emerging as a major center of studies in planetary geology, but no attempt had been made in the past to organize a broadly based meeting that would allow planetary geologists in Asia to meet with ones from more advanced centers, such as the United States and Europe, and that would include the participation of many geologists working primarily on terrestrial research. The Planetary Exploration Research Center (PERC) of the Chiba Institute of Technology hosted the first planetary geology field symposium in Asia to present results from recent planetary geology studies and to exchange ideas regarding terrestrial analogs (http://www.perc.it-chiba.ac.jp/meetings/pgfs2011/index.html).

Komatsu, Goro; Namiki, Noriyuki

2012-04-01

403

A Possible Aeronomy of Extrasolar Terrestrial Planets  

E-print Network

Terrestrial planetary systems may exist around nearby stars as the Earth-sized counterparts to the many giant planets already discovered within the solar neighborhood. In this chapter we first discuss the numerous techniques which have been suggested to search for extrasolar terrestrial planets. We then focus on the expected results from that technique in which an orbiting telescope or interferometer is used to obtain a visible or infrared spectrum of a planet, without contamination from the parent star. We show examples of such spectra for selected cases: the present Earth, the Neoproterozoic (snowball) Earth, a methane-rich Earth, and the present Mars and Venus. We conclude by discussing the implications of such spectra for the detection of life on an extrasolar terrestrial planet.

W. A. Traub; K. W. Jucks

2002-05-22

404

Body Image  

NSDL National Science Digital Library

Whether you feel flabby or fit depends on your brain as well as your waistline. This according to neurologist Henrik Ehrsson and his colleagues at University College, London. They stimulated the nerves in volunteers' bodies in a way that tricked them into feeling like their waistlines were shrinking. The illusion activated a part of the subjects' brains called the posterior parietal cortex, which integrates sensory signals from all over the body. The nerve stimulation for each person was the same, yet some experienced the shrinking sensation more strongly--and they had more activity in this part of the brain. That suggests that two people who have identical bodies might experience their body image differently. This may lead to a better understanding of anorexia and other body-image disorders. This Science Update also contains in text format details of the research, which leads to these findings presented in the Science Update podcast. It also offers links to the other podcasts topics and resources for further inquiry.

American Association for the Advancement of Science (; )

2006-01-02

405

[On mistakes in contemporary literatures of extra points in China].  

PubMed

Contemporary literatures which are taken as the base of literature study of extra points are insufficient and lack of reliability. The foundation of study is very weak. Based on abundant firsthand materials, analyses are made on the major problems of confounded names and locations, unclear quotation and source of reference in the study of contemporary literatures of extra points. Meanwhile, methods and way of thinking for solving the above mentioned problems are discussed in this article as well. PMID:23967640

Huang, Long-Xiang; Huang, You-Min

2013-06-01

406

Modified Newtonian Dynamics as an extra dimensional effect  

E-print Network

Modified Newtonian dynamics can be considered as an effect derived from a squeezable extra dimension space. The third law of Newtonian dynamics can be managed to remain valid in the 5-space. The critical acceleration parameter $a_0$ appears naturally as the bulk acceleration that has to do with the expanding universe in this setup. A simple toy model is presented in this Letter to show that consistent theory can be built with the help of the extra dimensional space.

W. F. Kao

2006-03-13

407

Fatigue Properties of Carburized Extra-fine Ni Steels  

Microsoft Academic Search

High compressibility Ni-Mo steels are leading candidate materials for high density PM steel gears. Recently developed admixed Ni-Mo steels containing extra-fine Ni powder limit the formation of soft Ni-rich austenitic phases thought to be detrimental for contact fatigue performance of PM steels. FLN2-4405 mixes containing both standard (STD Ni) and extra-fine Ni (XF Ni) powder were compacted into Charpy bars

T. F. Stephenson

408

Responses of terrestrial aridity to global warming  

NASA Astrophysics Data System (ADS)

The dryness of terrestrial climate can be measured by the ratio of annual precipitation (P) to potential evapotranspiration (PET), where the latter represents the evaporative demand of the atmosphere, which depends on the surface air temperature, relative humidity, wind speed, and available energy. This study examines how the terrestrial mean aridity responds to global warming in terms of P/PET using the Coupled Model Intercomparison Project phase 5 transient CO2 increase to 2 × CO2 simulations. We show that the (percentage) increase (rate) in P averaged over land is ~1.7%/°C ocean mean surface air temperature increase, while the increase in PET is 5.3%/°C, leading to a decrease in P/PET (i.e., a drier terrestrial climate) by ~3.4%/°C. Noting a similar rate of percentage increase in P over land to that in evaporation (E) over ocean, we propose a framework for examining the change in P/PET, in which we compare the change in PET over land and E over ocean, both expressed using the Penman-Monteith formula. We show that a drier terrestrial climate is caused by (i) enhanced land warming relative to the ocean, (ii) a decrease in relative humidity over land but an increase over ocean, (iii) part of increase in net downward surface radiation going into the deep ocean, and (iv) different responses of PET over land and E over ocean for given changes in atmospheric conditions (largely associated with changes in temperatures). The relative contributions to the change in terrestrial mean aridity from these four factors are about 35%, 35%, 15%, and 15%, respectively. The slight slowdown of the surface wind over both land and ocean has little impact on the terrestrial mean aridity.

Fu, Qiang; Feng, Song

2014-07-01

409

Terrestrial ecosystem regulation of interannual variability in atmospheric CO2  

NASA Astrophysics Data System (ADS)

Linking interannual variability in the global carbon dioxide, CO2, growth rate to its ecological and physical drivers may provide a means to improve predictions of long-term carbon-climate feedbacks. Many studies have attributed variability in the global CO2 record to a single factor, such as temperature, drought, or fire, or have asserted a combination of controls using complex ecosystem models. The evolving temporal and spatial structure of atmospheric CO2 may enable a more effective attribution of these processes, but has not been used systematically for this purpose. Here we simulated the fingerprints that terrestrial fluxes of carbon originating from temperature and drought stress and biomass burning imprint on the latitudinal and temporal distribution atmospheric CO2 for the 1997-2009 period using the GEOS-Chem atmospheric model. In general, temperature, precipitation, and drought signatures were highly correlated across different latitude bands, indicating that no single factor was the dominant mechanism explaining most of the CO2 variability. Fires had a unique signature, particularly in the northern hemisphere as a consequence of large events in the boreal forest during 1998, 2004, and 2008. Statistical models that combined these factors were able to explain between 20% and 40% of the CO2 variability in the northern hemisphere and 40-50% in the southern hemisphere. Net ecosystem exchange fluxes from the tropics, temperature, precipitation, and drought time series explained a considerable amount of flux variability in the NH and SH extra-tropics. Fires accounted for 25% to 30% of the total modeled variability in the NH (north of 23N) with this amount decreasing to about 20% in the SH (south of 23S). We also examined results from CMIP5 coupled Earth System Models to quantify patterns of variability in atmospheric CO2 originating from terrestrial ecosystems. We compared the variations correlated with temperature and precipitation variability to estimate the apparent climate sensitivity over the historical period, and examined the implications for long term carbon storage as climate changes. The results from these generalized simulations show that accounting for the latitudinal variability in atmospheric CO2 as well as the time-lag from transport facilitates a better relationship between fluxes and observed variations.

Keppel-Aleks, G.; Randerson, J. T.; Mu, M.; Doney, S. C.; van der Werf, G.; Collatz, G. J.; Morton, D. C.

2013-12-01

410

Body Imaging  

NASA Technical Reports Server (NTRS)

The high-tech art of digital signal processing (DSP) was pioneered at NASA's Jet Propulsion Laboratory (JPL) in the mid-1960s for use in the Apollo Lunar Landing Program. Designed to computer enhance pictures of the Moon, this technology became the basis for the Landsat Earth resources satellites and subsequently has been incorporated into a broad range of Earthbound medical and diagnostic tools. DSP is employed in advanced body imaging techniques including Computer-Aided Tomography, also known as CT and CATScan, and Magnetic Resonance Imaging (MRI). CT images are collected by irradiating a thin slice of the body with a fan-shaped x-ray beam from a number of directions around the body's perimeter. A tomographic (slice-like) picture is reconstructed from these multiple views by a computer. MRI employs a magnetic field and radio waves, rather than x-rays, to create images. In this photograph, a patient undergoes an open MRI.

2001-01-01

411

Body Imaging  

NASA Technical Reports Server (NTRS)

The high-tech art of digital signal processing (DSP) was pioneered at NASA's Jet Propulsion Laboratory (JPL) in the mid-1960s for use in the Apollo Lunar Landing Program. Designed to computer enhance pictures of the Moon, this technology became the basis for the Landsat Earth resources satellites and subsequently has been incorporated into a broad range of Earthbound medical and diagnostic tools. DSP is employed in advanced body imaging techniques including Computer-Aided Tomography, also known as CT and CATScan, and Magnetic Resonance Imaging (MRI). CT images are collected by irradiating a thin slice of the body with a fan-shaped x-ray beam from a number of directions around the body's perimeter. A tomographic (slice-like) picture is reconstructed from these multiple views by a computer. MRI employs a magnetic field and radio waves, rather than x-rays, to create images.

2001-01-01

412

Extra-Pair Mating and Evolution of Cooperative Neighbourhoods  

PubMed Central

A striking but unexplained pattern in biology is the promiscuous mating behaviour in socially monogamous species. Although females commonly solicit extra-pair copulations, the adaptive reason has remained elusive. We use evolutionary modelling of breeding ecology to show that females benefit because extra-pair paternity incentivizes males to shift focus from a single brood towards the entire neighbourhood, as they are likely to have offspring there. Male-male cooperation towards public goods and dear enemy effects of reduced territorial aggression evolve from selfish interests, and lead to safer and more productive neighbourhoods. The mechanism provides adaptive explanations for the common empirical observations that females engage in extra-pair copulations, that neighbours dominate as extra-pair sires, and that extra-pair mating correlates with predation mortality and breeding density. The models predict cooperative behaviours at breeding sites where males cooperate more towards public goods than females. Where maternity certainty makes females care for offspring at home, paternity uncertainty and a potential for offspring in several broods make males invest in communal benefits and public goods. The models further predict that benefits of extra-pair mating affect whole nests or neighbourhoods, and that cuckolding males are often cuckolded themselves. Derived from ecological mechanisms, these new perspectives point towards the evolution of sociality in birds, with relevance also for mammals and primates including humans. PMID:24987839

Eliassen, Sigrunn; Jørgensen, Christian

2014-01-01

413

Extra-pair mating and evolution of cooperative neighbourhoods.  

PubMed

A striking but unexplained pattern in biology is the promiscuous mating behaviour in socially monogamous species. Although females commonly solicit extra-pair copulations, the adaptive reason has remained elusive. We use evolutionary modelling of breeding ecology to show that females benefit because extra-pair paternity incentivizes males to shift focus from a single brood towards the entire neighbourhood, as they are likely to have offspring there. Male-male cooperation towards public goods and dear enemy effects of reduced territorial aggression evolve from selfish interests, and lead to safer and more productive neighbourhoods. The mechanism provides adaptive explanations for the common empirical observations that females engage in extra-pair copulations, that neighbours dominate as extra-pair sires, and that extra-pair mating correlates with predation mortality and breeding density. The models predict cooperative behaviours at breeding sites where males cooperate more towards public goods than females. Where maternity certainty makes females care for offspring at home, paternity uncertainty and a potential for offspring in several broods make males invest in communal benefits and public goods. The models further predict that benefits of extra-pair mating affect whole nests or neighbourhoods, and that cuckolding males are often cuckolded themselves. Derived from ecological mechanisms, these new perspectives point towards the evolution of sociality in birds, with relevance also for mammals and primates including humans. PMID:24987839

Eliassen, Sigrunn; Jørgensen, Christian

2014-01-01

414

Magnetic reconnection in the terrestrial magnetosphere  

SciTech Connect

An overview is given of quantitative comparisons between measured phenomena in the terrestrial magnetosphere thought to be associated with magnetic reconnection, and related theoretical predictions based on Petschek's simple model. Although such a comparison cannot be comprehensive because of the extended nature of the process and the relatively few in situ multipoint measurements made to date, the agreement is impressive where comparisons have been possible. This result leaves little doubt that magnetic reconnection does indeed occur in the terrestrial magnetosphere. The maximum reconnection rate, expressed in terms of the inflow Mach number, M/sub A/, is measured to be M/sub A/ = 0.2 +- 0.1.

Feldman, W.C.

1984-01-01

415

Tectonic Evolution of the Terrestrial Planets  

NASA Technical Reports Server (NTRS)

The NASA Planetary Geology and Geophysics Program supported a wide range of work on the geophysical evolution of the terrestrial planets during the period 1 April 1997 - 30 September 2001. We here provide highlights of the research carried out under this grant over the final year of the award, and we include a full listing of publications and scientific meeting presentations supported by this project. Throughout the grant period, our group consisted of the Principal Investigator and several Postdoctoral Associates, all at the Department of Terrestrial Magnetism (DTM) of the Carnegie Institution of Washington.

Solomon, Sean C.; Senski, David G. (Technical Monitor)

2002-01-01

416

Solar-Terrestrial Science Strategy Workshop  

NASA Technical Reports Server (NTRS)

The conclusions and recommendations reached at the Solar Terrestrial Science Strategy Workshop are summarized. The charter given to this diverse group was: (1) to establish the level of scientific understanding to be accomplished with the completion of the current and near term worldwide programs; (2) identify the significant scientific questions to be answered by future solar terrestrial programs, and the programs required to answer these questions; and (3) map out a program strategy, taking into consideration currently perceived space capabilities and constraints, to accomplish the identified program.

Banks, Peter M. (editor); Roberts, William T. (editor); Kropp, Jack (editor)

1989-01-01

417

Body Imaging  

NASA Technical Reports Server (NTRS)

Magnetic Resonance Imaging (MRI) and Computer-aided Tomography (CT) images are often complementary. In most cases, MRI is good for viewing soft tissue but not bone, while CT images are good for bone but not always good for soft tissue discrimination. Physicians and engineers in the Department of Radiology at the University of Michigan Hospitals are developing a technique for combining the best features of MRI and CT scans to increase the accuracy of discriminating one type of body tissue from another. One of their research tools is a computer program called HICAP. The program can be used to distinguish between healthy and diseased tissue in body images.

1990-01-01

418

Evolution of the terrestrial planets (geological and petrological data)  

NASA Astrophysics Data System (ADS)

How the terrestrial solid planetary bodies were developed? What major stages of their irreversible evolution took place before they turned into "dead" stone balls? We discuss these problems on examples of the Earth and the Moon, which evolution studied the best. According to modern views, after accretion of these bodies, magma oceans of some hundreds km deep appeared on their surface. According to Jeffries (1929), solidification of large molted bodies, because of the difference between adiabatic gradient in silicate melts (0.3oC/km) and gradient of their melting points (3oC/km), could be going only upwards, from the bottom to the surface. As a result a powerful crystallizing differentiation of the oceans' magmas took place with accumulation of the most low-melting components to the surface. Due to different deep of the oceans on the Moon and the Earth, the primordial crusts on these bodies were rather different: mafic on the Moon and sialic on the Earth. Geological evolution of the Earth began 4 Ga ago from appearance of Archean granite-greenstone terranes (GGT) and divided them granulite belts. Mantle-derived magmatism of high-Mg komatiite-basaltic series was located in greenstone belts, which formed irregular network within GGTs and composed 10-15 The sharp change of the magmatic activity with appearance in global scale of geochemical-enriched Fe-Ti picrites and basalts occurred in interval 2.3-2.0 Ga ago. Such melts was typical for Phanerozoic within-plate magmatism and linked with thermochemical mantle plumes of the second generation, which ascended from the liquid core-mantle boundary (CMB). It was followed by plate tectonic appearance 2 Ga ago and from this particular time such tectonic regime has existed till now. From this particular time, ancient Earth's continental crust began to involved in subduction processes and interchange by secondary oceanic crust which forms about 70Where this geochemical-enriched material was conserved and how it was activated? We suggest that such situation could be possible only in case when (1) accretion of the Earth was heterogeneous, and (2) warming of the Earth occurred downwards, from surface to core. It was, probably, a result of moving inwards a wave of deformations, accompanied by emission of heat. At the first stage the wave went through depleted (in result of directed solidification of magma ocean) mantle and led to appearance of mantle superplumes of the first generation. At the second stage it reached iron core, melted it, which led to appearance of mantle supeplumes of the second generation (thermochemical), enriched in fluids, Fe, Ti, alcalies, incompatible elements, etc. Material of such superplumes could rich more shallow levels and led to active interactions of their extended heads with solid lithosphere, which caused changing of tectonic activity character. We suggest that terrestrial planets were developed at the same, but shortened scenario, and more quick. At the Moon the earliest magmatism of highlands were close to terrestrial early Paleoproterozoic SHMS and at the boundary 3.9-3.8 Ga ago was changed by maria magmatism, close in composition to MORB and OIB. By analogy with the Earth, we suggest that maria magmatism was linked with ascending of thermochemical superplumes, generated at the lunar CMB, when it's liquid iron core was yet existed. Ancient planums on Mars and tesseras at the Venus among vast planides, composed by basaltic flows can also evidence about two stages of their development. Judging on absence of magnetic field, their liquid cores ("energetic hearts") are of no consequence and they are dead bodies now. Work was supported by grant RFBR 07-05-00496

Sharkov, Evgenii

419

Domain with Noncompactified Extra Dimensions in Multidimensional Universe with Compactified Extra Dimensions  

E-print Network

It is supposed that in our Universe with compactified extra dimensions (ED) the domains exist with noncompactified ED. Such domain can be a wormhole-like solution in multidimensional gravity (MD), located between two null surfaces. With the availability of compactification mechanism this MD domain can be joined on null surfaces with two black holes filled by gauge field. Solution of this kind in MD gravity on the principal bundle with structural group SU(3) is obtained. This solution is wormhole-like object located between two null surfaces $ds^2=0$. In some sense these solutions are dual to black holes: they are statical spherically symmetric solutions under null surfaces whereas black holes are statical spherically symmetric solutions outside of event horizon.

V. D. Dzhunushaliev

1997-12-16

420

Body Circulation  

NSDL National Science Digital Library

Students are introduced to the circulatory system, the heart, and blood flow in the human body. Through guided pre-reading, during-reading and post-reading activities, students learn about the circulatory system's parts, functions and disorders, as well as engineering medical solutions. By cultivating literacy practices as presented in this lesson, students can improve their scientific and technological literacy.

Integrated Teaching and Learning Program,

421

Body Levers.  

ERIC Educational Resources Information Center

Explains how the muscle and bone arrangement of the human body can be used in teaching the principles of simple machines. Presents an activity that investigates the lever system of the forearm. Includes background information on levers and suggests questions for classroom discussion. (ML)

Chiappetta, Eugene L.

1987-01-01

422

Evolution of the structure of iron meteorites under terrestrial climate  

NASA Astrophysics Data System (ADS)

Introduction: Meteoritic iron is affected by many factors in terrestrial conditions. First of all, abundance of water induces an oxidization process. Despite rather high nickel concentration in meteoritic iron, rust is forming on a surface of extraterrestrial matter. But also transformation processes occur inside meteorites at rather low climatic temperatures (0.15 of the melting temperature). Such reaction has been observed for the first time in the Bilibino meteorite [1]. Experiments: Structural changes in kamacite were investigated in ancient iron meteorite falls (Aliskerovo IIIAB, Bilibino IIAB). All of them demonstrate uncompleted recrystallization. Polished sections were analyzed using inverted optical microscope Axiovert 40 MAT and SEM SIGMA VP with EDS and EBSD units. Results: Different percentage of recrystallization was found in Aliskerovo and Bilibino meteorites. 4 % of the section surface in Aliskerovo is occupied by recrystallization products. This value for Bilibino is equal to 80 %. It was noticed that recrystallization started from the kamacite-rhabdite boundaries in the Bilibino meteorite and from the kamacite-schreibersite boundaries in the Aliskerovo meteorite. There are strongly-etched sites in the recrystallized zones. One can suggest that these sites are traces of former boundaries. It is possible to think that the boundaries were moving with jumps because of the position of these sites in the recrystallized zone. Also it was noticed that there is a net of cracks before the recrystallization reaction front. A possible reason for this phenomenon is a wedge of extra material which generates an elastic stress field in the vicinity of the grain boundary [2]. All these phenomena can be explained using the Kirkendall effect on the grain boundary: the boundary shift is the result of the different concentrations of vacancies between the boundary sides.

Yakovlev, G.; Grokhovsky, V.

2014-07-01

423

Terrestrial ecosystem feedbacks to global climate change  

Microsoft Academic Search

Anthropogenic greenhouse gases are expected to induce changes in global climate that can alter ecosystems in ways that, in turn, may further affect climate. Such climate-ecosystem interactions can generate either positive or negative feedbacks to the climate system, thereby either enhancing or diminishing the magnitude of global climate change. Important terrestrial feedback mechanisms include COâ fertilization (negative feedbacks), carbon storage

Daniel A. Lashof; Benjamin J. DeAngelo; Scott R. Saleska; John Harte

1997-01-01

424

APPLICATION OF TERRESTRIAL LASER SCANNING FOR SHIPBUILDING  

Microsoft Academic Search

Recently, a laser scanner technology has been receiving more attention. Nowadays use of terrestrial laser scanners (TLS) is continuously increasing. This technique offers the possibility of measuring millions of points within short period of time. Thus, it is possible to record complete 3D objects efficiently. In this communication the process followed to model the hull and the deck of the

K. Biskup; P. Arias; H. Lorenzo; J. Armesto

2007-01-01

425

Using observational data to evaluate global terrestrial  

E-print Network

to model land-atmosphere carbon exchange #12;Terrestrial Biospheric Models Well-informed Carbon cycle #12;Models Well-informed Carbon cycle projections Input data Initial conditions Parameter values Atmosphere Coupled Land Models Coupled carbon-climate models disagree on the continued strength of the net

426

Carbohydrate formation in rewetted terrestrial cyanobacteria  

Microsoft Academic Search

In the terrestrial cyanobacterium Nostoc commune Vauch. formation of carbohydrate polymers was measured upon rewetting the mats in a light-dark regime. To discriminate between carbohydrates of different physiological function, total carbohydrate was determined as anthrone-reactive material (ARM) and storage carbohydrate (glycogen) assayed by an enzymic test. In the dry thalli glycogen was found to represent less than one tenth of

A. Ernst; T.-W. Chen; P. Böger

1987-01-01

427

The geophysical signature of terrestrial impact craters  

Microsoft Academic Search

Terrestrial impact craters are examined in terms of their geophysical characteristics which can be used to identify additional impact craters. The geophysical signatures examined include the circular gravity low which is modeled for the cases of bowl-shaped and complex craters. The size of the gravity anomaly for both types of craters is established and modeled with known morphometric parameters of

M. Pilkington; R. A. F. Grieve

1992-01-01

428

Widespread genetic exchange among terrestrial bacteriophages  

E-print Network

Widespread genetic exchange among terrestrial bacteriophages Olin K. Silander*§ , Daniel M October 27, 2005 (received for review April 15, 2005) Bacteriophages are the most numerous entities Microbes are the most numerous entities in the biosphere, and viruses that infect bacteria (bacteriophages

Hartl, Daniel L.

429

Ammonia transport by terrestrial and aquatic insects  

Microsoft Academic Search

Ammonia, an end product from amino acid and nucleic acid metabolism, is highly toxic for most animals. This review will provide an update on nitrogen metabolism in terrestrial and aquatic insects with emphasis on ammonia generation and transport.Aspects that will be discussed include metabolic pathways of nitrogenous compounds, the origin of ammonia and other nitrogenous waste products, ammonia toxicity, putative

Dirk Weihrauch; Andrew Donini; Michael J. O’Donnell

430

Modelling the Eccentricities of the Terrestrial Planets  

Microsoft Academic Search

Numerical models of late-stage planet formation have successfully reproduced a number of the observed characteristics of the terrestrial planets. However, understanding the origin of their orbital eccentricities remains a problem. Earth and Venus currently have very low orbital eccentricities: roughly 0.03 when averaged over long timescales. In general, numerical simulations of planetary accretion produce Earth analogues with significantly larger eccentricities,

J. Chambers

2003-01-01

431

Neutron production in terrestrial gamma ray flashes  

Microsoft Academic Search

Terrestrial gamma ray flashes (TGFs) are brief bursts of photons with energies up to 20 MeV typically observed in association with lightning. Such energetic photons may undergo photonuclear reactions with nontrivial cross section in the vicinity of the giant dipole resonance. Pulses of neutrons have been observed experimentally in coincidence with lightning, suggesting such reactions are observable. We present simulations

B. E. Carlson; N. G. Lehtinen

2010-01-01

432

First RHESSI terrestrial gamma ray flash catalog  

Microsoft Academic Search

We present a summary of data from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) terrestrial gamma ray flash (TGF) catalog. We describe the RHESSI search algorithm and discuss its limitations due to its design emphasis on cleanliness rather than completeness. This search algorithm has identified 820 TGFs between March of 2002 and February of 2008. Radiation damage to

B. W. Grefenstette; D. M. Smith; B. J. Hazelton; L. I. Lopez

2009-01-01

433

Terrestrial Accretion from the Solar Wind  

Microsoft Academic Search

MR. HARRISON has raised a number of important issues which can only be answered tentatively at the present time. Presumably the oxygen is liberated from terrestrial rocks by solar ultra-violet radiation, and an estimate of the mean quantum efficiency of this photochemical process should be readily obtainable in the laboratory, by irradiation of outgassed rock samples in an evacuated chamber,

C. M. de. Turville

1961-01-01

434

Some Studies of Terrestrial Impact Cratering Rate  

Microsoft Academic Search

In 1984, a 28.4 Myr periodicity was detected in the ages of terrestrial impact craters and a 26 Myr periodicity in the epochs of mass extinctions of species. Periodic comet showers from the Oort cloud seemed to cause catastrophic events linked to mass extinctions of species. Our first study revealed that the only significant detected periodicity is the ``human signal''

L. Jetsu

2011-01-01

435

UV-B EFFECTS ON TERRESTRIAL ECOSYSTEMS  

EPA Science Inventory

Dpeletion of stratospheric O3 layer should result in enhanced levels of ultraviolet-B (UV-B) radiation at the earth's surface compared to present, with potentially damaging effects on biological systems. his paper briefly summarizes some key findings for UV-B effects on terrestri...

436

Terrestrial solar cells —present and future  

Microsoft Academic Search

In this paper the principles of operation of various types of solar cell are described. Progress in photovoltaics is traced through the development of the monocrystalline silicon cell for space applications where the emphasis is upon reliability and power\\/weight ratio, to terrestrial cells where the emphasis is upon low-cost production. The role of other contenders such as polycrystalline silicon, amorphous

B. T. Debney; J. R. Knight

1978-01-01

437

Dinosaurs and the Cretaceous Terrestrial Revolution  

E-print Network

Dinosaurs and the Cretaceous Terrestrial Revolution Graeme T. Lloyd1,*, Katie E. Davis2 , Davide of dinosaurs reached its highest peak during the mid- and Late Cretaceous, the 50 Myr that preceded their extinction, and yet this explosion of dinosaur diversity may be explained largely by sampling bias. It has

Benton, Michael

438

MICROBIAL ECOLOGY OF THE TERRESTRIAL SUBSURFACE  

EPA Science Inventory

A current view is presented of the microbial ecology of the terrestrial subsurface by considering primarily the ecology of shallow aquifer sediments. The properties of the aquifer sediments and groundwater determine their ability to support microbial life and control the abundanc...

439

Connecting terrestrial to celestial reference frames  

NASA Astrophysics Data System (ADS)

In this paper we outline several problems related to the realization of the international celestial and terrestrial reference frames - the ICRF and ITRF - at the millimeter level of accuracy, with emphasis on ICRF issues. We consider here the current status of the ICRF, the interrelationship between the ICRF and ITRF, and considerations for future ICRF realizations.

Malkin, Z.

2015-03-01

440

ESTUARINE WETLANDS (CHAPTER: TERRESTRIAL VEGETATION OF CALIFORNIA)  

Technology Transfer Automated Retrieval System (TEKTRAN)

This chapter on estuarine wetlands is a peer-reviewed contribution to the 3rd edition of Terrestrial Vegetation of California (editors: M.G. Barbour, T. Keeler-Wolf, and A. Schoenherr, University of California Press). The objective of the chapter is to describe the distribution, floristic compositi...

441

Internal structure of massive terrestrial planets  

Microsoft Academic Search

Planetary formation models predict the existence of massive terrestrial planets and experiments are now being designed that should succeed in discovering them and measuring their masses and radii. We calculate internal structures of planets with one to ten times the mass of the Earth (Super-Earths) to obtain scaling laws for total radius, mantle thickness, core size and average density as

Diana Valencia; Richard J. O'Connell; Dimitar D. Sasselov

2006-01-01

442

Subsolidus convective cooling histories of terrestrial planets  

Microsoft Academic Search

The subsolidus convective cooling histories of terrestrial planets evolving from hot initial states are investigated quantitatively. A simple analytic model simulating average heat flux from a vigorously convecting mantle and incorporating a mantle viscosity proportional to mantle temperature and a lithosphere which thickens as the planet cools is employed. Heat flux from the convecting mantle is calculated on the basis

G. Schubert; P. Cassen; R. E. Young

1979-01-01

443

Terrestrial Planet Formation in the ? Centauri System  

Microsoft Academic Search

We examine the late stages of terrestrial planet formation around each star in theCentauri A and ? Centauri B binary system. Each integration begins with a '' bimodal '' mass distribution of 14 large embryos embedded in a disk of smaller planetesimals orbiting one of the stars. These initial conditions were chosen because when they are used in simulations about

Elisa V. Quintana; Jack J. Lissauer; John E. Chambers; Martin J. Duncan

2002-01-01

444

High efficiency, long life terrestrial solar panel  

NASA Technical Reports Server (NTRS)

The design of a high efficiency, long life terrestrial module was completed. It utilized 256 rectangular, high efficiency solar cells to achieve high packing density and electrical output. Tooling for the fabrication of solar cells was in house and evaluation of the cell performance was begun. Based on the power output analysis, the goal of a 13% efficiency module was achievable.

Chao, T.; Khemthong, S.; Ling, R.; Olah, S.

1977-01-01

445

One common structural peculiarity of the Solar system bodies including the star, planets, satellites and resulting from their globes rotation  

NASA Astrophysics Data System (ADS)

Often observed a sensible difference in appearance and structure between tropical and extra-tropical zones of various heavenly bodies including rocky and gas planets, satellites and Sun compels to look for a common reason of such phenomenon. All bodies rotate and their spherical shape makes zones at different latitudes to have differing angular momenta as a distance to the rotation axis diminishes gradually from the equator to the poles (this is felt particularly when one launches rockets into space -preferable more cheap launches are from the equatorial regions - Kourou is better than Baikonur). One of remarkable changes occurs at tropics. As a single rotating planetary body tends to have angular momenta of its tectonic blocks equilibrated it starts mechanisms leveling this basic physical property. At tropical zones (bulged also due to the rotation ellipsoid) the outer shell - crust as a consequence tends to be destroyed, sunk, subsided and shrunk; a density of crust material changes; the atmosphere reacts changing chemistry and structure; in terrestrial anthroposphere man looses its mass and stature. But according to the Le Chatelier rule mechanisms with an opposing tendency also begin to act. At Earth the wide planetary long tropical zone is marked by destruction of the crust. It is demonstrated by development of numerous islands of the Malay Archipelago (the Sunda Isls., Maluku Isls, Philippines) between the Southeastern Asia and Australia. In Africa and South America huge depressions of the Congo and Amazon Rivers develops where the Archean crust is subsided to depths of more than 2 km. In the Pacific along the equator numerous islands of Micronesia occur. Subsidence of the basaltic oceanic crust is followed by an intensive folding and faulting of basalt and sedimentary layers (Fig. 1) as a larger mass must be held by a smaller space (a planetary radius is diminished). The central Atlantic is very demonstrative in this sense suffering huge transform fault zones changing to more quite tectonics to the north and south where basaltic effusions form large provinces. This addition of dense basalts to the crust plays to increasing angular momentum of the extra-tropical blocks. At Mars the widespread enigmatic chaotic and fretted terrains at the highland-lowland boundary could be considered as traces of the crust destruction along the wide tropical belt. A system of hillocks and their relics and separating them depressions is controlled by a crosscutting tectonics. Prevailing subsidence here is characteristic. At Saturn a wide tropical zone usually has higher albedo than extra-tropical ones. Relatively heavier methane clouds in the H-He atmosphere are absent around the equator and concentrated on the higher latitudes (Fig. 2). In the tropical zone of Titan the darker methane lowlands (Fig. 3) are normally rippled in at least two directions with spacing a few km to 20 km (such forms erroneously are taken as dunes) (Fig. 4). This subsidence rippling gradually is replaced by smooth surfaces of dark basins (possibly liquid methane) at the higher northern and at lesser degree southern latitudes. This planetary pattern (Fig. 3, 4) is comparable with a behavior of the basalt floor of terrestrial oceans. On Iapetus the wide equatorial zone of the bright trailing hemisphere is distinguished by relatively numerous craters with darkened floors (Fig. 5). This terrain connects both flanks of the dark leading hemisphere and is a continuation of its equatorial bulge (a squeezed out feature as a result of the dark hemisphere subsidence). Thus looks tending subside and disintegrate tropical terrain on the uplifted bright hemisphere. Around the Tethys' equator there is a band of slightly darker surface material (Fig. 6). It may be an area of less contaminated ice and ice with a different structure than ice at higher latitudes as think Cassini scientists. If it is coarser-grained (more loosely packed) and purer then the equatorial region tends to be less dense diminishing its angular momentum. A crosscutting wave rippling producing chains of

Kochemasov, , G. G.

2008-09-01

446

Leaf element concentrations of terrestrial plants across China are  

E-print Network

with leaf elements responsible for cell structure and enzymes. Main conclusions Leaf element concentrationsRESEARCH PAPER Leaf element concentrations of terrestrial plants across China are influenced cycles of terrestrial eco- systems are strongly affected by leaf element concentrations. Understanding

Slik, Ferry

447

EENY-220 Terrestrial Amphipods or “Lawn Shrimp ” (Crustacea:  

E-print Network

Amphipods comprise an order of crustacea, shrimp-like in form, which contains mostly marine and freshwater forms. While some species are terrestrial, they still require moist habitats. These terrestrial species are sometimes referred to

Amphipoda Talitridae; Thomas R. Fasulo

448

The Role of Extra-Credit Assignments in the Teaching of World Languages  

ERIC Educational Resources Information Center

The granting of extra credit is a hotly debated topic in all fields of education. Teachers are reluctant to offer extra credit for fear of inflating grades, but students are persistent in their demands for extra-credit points to which they have become accustomed. This article considers extra-credit assignments in the teaching of world languages.…

Alley, David

2011-01-01

449

The coevolution of circumperineal color and terrestriality.  

PubMed

Old World monkeys (Cercopithecoidea) are unusual among primates for the high percentage of species exhibiting circumperineal coloration, as well as the large percentage of highly terrestrial species. Kingdon [1974, 1980] suggested that circumperineal skin coloration is functionally related to terrestriality, but this hypothesis has not been tested. From the literature, we collected data on habitat use (terrestrial/arboreal) and circumperineal coloration (present/absent) for 78 species. Indeed, among the 78 species surveyed here, 75% of them fall into either the category of colored circumperineals with terrestrial lifestyle, or of uncolored circumperineals with arboreal lifestyle (?(2) (1)?=?19.550, P?terrestrial ecology. Am. J. Primatol. 77:547-557, 2015. © 2015 Wiley Periodicals, Inc. PMID:25612177

Pampush, James D; Cramer, Jennifer D

2015-05-01

450

Terrestrial Planet Formation in Binary Star Systems  

E-print Network

A binary star system is the most common result of the star formation process, and binary companions can disrupt both the formation of terrestrial planets and their long term prospects for stability. We present results from a large set of numerical simulations of the final stages of terrestrial planet formation - from Moon- to Mars-sized planetary embryos to planets - in main-sequence binary star systems. We examine planetary accretion around both stars ('P-type' circumbinary orbits) or individual stars ('S-type' orbits) in binary systems, including terrestrial planet formation around each star in Alpha Centauri AB, the closest binary star system to the Sun. For comparison, we also simulate planetary growth from the same initial disk placed in the Sun-Jupiter-Saturn system and also around the Sun with neither giant planets nor a stellar companion perturbing the system. Our simulations show that giant and stellar companions not only truncate the disk, but hasten the accretion process by stirring up the planetary embryos to higher eccentricities and inclinations. Terrestrial planets similar to those in our Solar System formed around individual stars in simulations with the binary periastron (closest approach) greater than about 5 AU. Terrestrial planet growth within circumbinary disks was uninhibited around inner binary star systems with binary apastrons (maximum separation) less than ~0.2 AU. Results from our simulations can be scaled for different stellar and disk parameters. Approximately 50 - 60% of binary star systems - from contact binaries to separations of nearly a parsec - satisfy these constraints. Given that the galaxy contains more than 100 billion star systems, a large number of systems remain habitable based on the dynamic considerations of this research.

Elisa V. Quintana; Jack J. Lissauer

2007-05-23

451

Aerodynamic Analysis of Tektites and Their Parent Bodies  

NASA Technical Reports Server (NTRS)

Experiment and analysis indicate that the button-type australites were derived from glassy spheres which entered or re-entered the atmosphere as cold solid bodies; in case of average-size specimens, the entry direction was nearly horizontal and the entry speed between 6.5 and 11.2 km/sec. Terrestrial origin of such spheres is impossible because of extremely high deceleration rates at low altitudes. The limited extension of the strewn fields rules out extraterrestrial origin of clusters of such spheres because of stability considerations for clusters in space. However, tektites may have been released as liquid droplets from glassy parent bodies ablating in the atmosphere of the earth. The australites then have skipped together with the parent body in order to re-enter as cold spheres. Terrestrial origin of a parent body would require an extremely violent natural event. Ablation analysis shows that fusion of opaque siliceous stone into glass by aerodynamic heating is impossible.

Adams, E. W.; Huffaker, R. M.

1962-01-01

452

Peering into Terrestrial Planet Formation: New Studies of Young Debris Disks  

NASA Astrophysics Data System (ADS)

Young debris disks are an excellent tool for studying last stages of terrestrial planet formation. During this stage, planetesimals in the disk might deliver volatiles such as water to the still-forming terrestrial planets. Though these planetesimals are undetectable, the dust in the disk provides clues to the location and composition of their parent bodies. I will discuss my work studying dust in young debris disks (10-30 Myrs-old) in the infrared and sub-millimeter with the Herschel Space Observatory as part of the Herschel GASPS team. We found that there is a lot of scatter in disk properties between disks of the same age, but there appears to be a trend between the stellar and disk temperatures. I will also discuss our detailed modeling of one well-studied debris disk, HD32297. Spectral energy distribution modeling indicates the presence of comet-like grains in the outer disk of HD32297, suggesting the presence of water rich planetesimals that can deliver water to terrestrial planets. HST STIS spectra of this disk show a red color that may be indicative of organic material. Together, these studies help paint a more complete picture of the last stages of terrestrial planet formation in young debris disks.

Donaldson, Jessica; Roberge, A.; Herschel GASPS Team

2014-01-01

453

A potential mechanism for allometric trabecular bone scaling in terrestrial mammals.  

PubMed

Trabecular bone microstructural parameters, including trabecular thickness, spacing, and number, have been reported to scale with animal size with negative allometry, whereas bone volume fraction is animal size-invariant in terrestrial mammals. As for the majority of scaling patterns described in animals, its underlying mechanism is unknown. However, it has also been found that osteocyte density is inversely related to animal size, possibly adapted to metabolic rate, which shows a negative relationship as well. In addition, the signalling reach of osteocytes is limited by the extent of the lacuno-canalicular network, depending on trabecular dimensions and thus also on animal size. Here we propose animal size-dependent variations in osteocyte density and their signalling influence distance as a potential mechanism for negative allometric trabecular bone scaling in terrestrial mammals. Using an established and tested computational model of bone modelling and remodelling, we run simulations with different osteocyte densities and influence distances mimicking six terrestrial mammals covering a large range of body masses. Simulated trabecular structures revealed negative allometric scaling for trabecular thickness, spacing, and number, constant bone volume fraction, and bone turnover rates inversely related to animal size. These results are in agreement with previous observations supporting our proposal of osteocyte density and influence distance variation as a potential mechanism for negative allometric trabecular bone scaling in terrestrial mammals. The inverse relationship between bone turnover rates and animal size further indicates that trabecular bone scaling may be linked to metabolic rather than mechanical adaptations. PMID:25655770

Christen, Patrik; Ito, Keita; van Rietbergen, Bert

2015-03-01

454

Oligarchic and giant impact growth of terrestrial planets in the presence of gas giant planet migration  

E-print Network

We present the results of N--body simulations which examine the effect that gas giant planet migration has on the formation of terrestrial planets. The models incorporate a 0.5 Jupiter mass planet undergoing type II migration through an inner protoplanet--planetesimal disk, with gas drag included. Each model is initiated with the inner disk being at successively increased levels of maturity, so that it is undergoing either oligarchic or giant impact style growth as the gas giant migrates. In all cases, a large fraction of the disk mass survives the passage of the giant, either by accreting into massive terrestrial planets shepherded inward of the giant, or by being scattered into external orbits. Shepherding is favored in younger disks where there is strong dynamical friction from planetesimals and gas drag is more influential, whereas scattering dominates in more mature disks where dissipation is weaker. In each scenario, sufficient mass is scattered outward to provide for the eventual accretion of a set of terrestrial planets in external orbits, including within the system's habitable zone. An interesting result is the generation of massive, short period, terrestrial planets from compacted material pushed ahead of the giant. These planets are reminiscent of the short period Neptune mass planets discovered recently, suggesting that such `hot Neptunes' could form locally as a by-product of giant planet migration.

Martyn J. Fogg; Richard P. Nelson

2005-07-07

455

Orbital Evolution of Extra-Solar Giant Planets  

NASA Astrophysics Data System (ADS)

The recent discoveries (Mayor and Queloz, 1995; Marcy and Butler, 1996; Butler and Marcy, 1996) of extra-solar giant planets (EGPs) at small heliocentric distances have prompted questions about the formation, evolution, and migration of these EGPs. The location of several EGPs at much less than 1 AU from their primaries has proved to be particularly problematic. Since it is thought that EGPs do not form that close to their primaries (Guillot et al., 1996), a reasonable conclusion is that these close companions formed elsewhere in their solar systems and subsequently moved to their present small heliocentric distances. Jupiter-style planetary formation is thought to initiate at the ice line ( ~ several AU) (Boss, 1995), with possible subsequent inward migration (Lin and Papaloizou, 1986). But how can a massive body stop its inward migration before crashing into its star? We investigate the orbital evolution of an EGP with our fully implicit numerical model. Inward migration is caused by angular momentum exchange between the planet and disk (Takeuchi et al., 1996, Lin and Papaloizou, 1986). After the planet has migrated to much less than 1 AU, its inward motion can be halted by outward torques due to tides (Lin et al., 1996) and due to angular momentum exchange from Roche lobe overflow and mass loss (Benz et al., 1990). EGPs may stably survive, some at new, smaller masses, at small heliocentric distances for greater than 10(7) years, by which time the disk has dissipated (Zuckerman et al., 1995) and the torques have nearly vanished. This mechanism may explain the presence of EGPs at small heliocentric distances. References: Benz et al., 1990, Ap. J., 348, 647. Boss, 1995, Science, 267, 360. Butler and Marcy, 1996, Ap. J., 464, L153. Guillot et al., 1996, Ap. J., 459, L35. Lin et al., 1996, Nature, 380, 606. Lin and Papaloizou, 1986, Ap. J., 309, 846. Marcy and Butler, 1996, Ap. J., 464, L147. Mayor and Queloz, 1995, Nature, 378, 355. Takeuchi et al., 1996, Ap. J., 460, 832. Zuckerman et al., 1995, Nature, 373, 494. Acknowledgement: This work is supported in part under an NSF Graduate Research Fellowship.

Trilling, D. E.; Benz, W.; Guillot, T.; Lunine, J. I.

1996-09-01

456

The Behaviour ofIodine in the Terrestrial Environment.  

E-print Network

The Behaviour ofIodine in the Terrestrial Environment. An Investigation of the Possible Roskilde, Denmark Febtuary 1990 #12;1 Risø-M-2851 THE BEHAVIOUR OF IODINE IN THE TERRESTRIAL ENVIRONMENT influence the migration behaviour of iodine in the terrestrial environment. It is stated that the organic

457

Terrestrial manganese-53 --A new monitor of Earth surface processes  

E-print Network

Terrestrial manganese-53 -- A new monitor of Earth surface processes Joerg M. Schaefer a,, Thomas of the terrestrial cosmogenic radionuclide manganese-53 (T1/2 =3.7 Ma) measured in thirteen samples from nine dolerite surfaces in the Dry Valleys, Antarctica. The terrestrial manganese-53 concentrations correlate

Winckler, Gisela

458

Carbon Metabolism of the Terrestrial Biosphere: A Multitechnique Approach  

E-print Network

and validate terrestrial biospheric models. An iteration and reit- eration of top-down and bottom-up approaches: 10.1007/s100210000014 ECOSYSTEMS 2000 Springer-Verlag 115 #12;INTRODUCTION The world's terrestrialCOMMENTARY Carbon Metabolism of the Terrestrial Biosphere: A Multitechnique Approach for Improved

Ehleringer, Jim

459

Tuesday, March 14, 2006 TERRESTRIAL PLANET FORMATION AND DIFFERENTIATION  

E-print Network

Tuesday, March 14, 2006 TERRESTRIAL PLANET FORMATION AND DIFFERENTIATION 1:30 p.m. Marina Plaza, and water condenses at terrestrial planet formation region. Then, planetesimals mainly composed of ice. 2:00 p.m. O'Brien D. P. * Morbidelli A. Levison H. F. Simulations of Terrestrial Planet Formation

Rathbun, Julie A.

460

Interferometer Architecture Trade Studies for the Terrestrial Planet Finder Mission  

E-print Network

Interferometer Architecture Trade Studies for the Terrestrial Planet Finder Mission by Brian J #12;2 #12;Interferometer Architecture Trade Studies for the Terrestrial Planet Finder Mission by Brian and then used to conduct trade studies for NASA's Terrestrial Planet Finder (TPF) Mission. A software tool