|
|
|
1982-09-27
A flexible connector apparatus used to join two stiff non-deformable members, such as piping, is described. The apparatus is provided with one or more flexible sections or assemblies each utilizing a bellows of a rolling cuff type connected between two ridge members, with the bellows being supported by a back-up ring, such that only the curved end sections of the bellows are unsupported. Thus, the bellows can be considered as being of a tube-shaped configuration and thus have high pressure resistance. The components of the flexible apparatus are sealed or welded one to another such that it is fluid tight.
The bellows at low beta and beam stabilities
1989-11-01
The Tevatron dipoles and quadrupoles are at superconducting temperature while the low-beta insertion is at room temperature. In order to limit the heat flowing into the low temperature region, the low-beta insertion is joined to the ring through a special bellows. The beam-pipe radius is 3.7 cm corresponding to a cutoff frequency of 3.10 GHz for the monopole mode and 2.38 GHz for the dipole mode. There are approximately 32 such bellows. Each bellows has a narrow gap of about 6 mm at the beam pipe and opens up into a {approximately} 7 cm wide cavity at larger radius. The bellows ripples start at a radius of about 12 cm. We therefore expect the bellows to contribute sharp resonances below cutoff at frequency below 1 GHz. In this article, we are going to compute the longitudinal and transverse impedances and to check whether they can drive any collective instabilities of the beam bunches. 4 figs., 3 tabs.
Flow induced vibrations in metal bellows
Dynamic structural analysis and flow induced stress analysis of metal bellows in Apollo Saturn launch vehicle systems
Simulation of HOM Leakage in the PEP-II Bellows
2005-06-07
An important factor that limits the PEP-II from operating at high currents is higher-order-mode (HOM) heating of the bellows. One source of HOM heating is the formation of trapped modes at the bellows as a result of geometry variation in the vacuum chamber, for example, the masking near the central vertex chamber. Another source comes from HOMs generated upstream that leak through the gaps between the bellows fingers. Modeling the fine details of the bellows and the surrounding geometry requires the resolution and accuracy only possible with a large number of mesh points on an unstructured grid. We use the parallel finite element eigensolver Omega3P for trapped mode calculations and the S-matrix solver S3P for transmission analysis. The damping of the HOMs by the use of absorbers inside the bellows will be investigated.
Design of the ISX-B differentially pumped bellows
1977-01-01
The structural design and operational aspects of the ISX-B differentially pumped bellows assembly are discussed. The ISX-B vacuum vessel consists of two monolithic halves which are rectangular in cross section and joined together by short bellows which provide electrical resistance around the vesel in the toroidal direction. The bellows are unable to withstand atmospheric pressure and must be mounted within an outer, thick-wall vessel with the space between bellows and wall being pumped down to a partial vacuum.
Damping Higher Order Modes in the PEP-II B-Factory Vertex Bellows
2005-06-30
Higher stored currents and shorter bunch lengths are requirements for increasing luminosity in colliding storage rings. As a result, more HOM power is generated in the IP region. This HOM power propagates to sensitive components causing undesirable heating, thus becoming a limiting issue for the PEP-II B-factory. HOM field penetration through RF shielding fingers has been shown to cause heating in bellows structures. To overcome these limitations, a proposal to incorporate ceramic absorbers within the bellows cavity to damp these modes is presented. Results show that the majority of modes of interest are damped, the effectiveness depending on geometrical considerations. An optimal configuration is presented for the PEP-II B-factory IR bellows component utilizing commercial grade ceramics with consideration for heat transfer requirements.
Tokamak Fusion Test Reactor vacuum vessel: development of electrical resistance bellows
1977-01-01
The design, evolution, fabrication, and installation of the development electrical resistance bellows for the vacuum vessel of the TFTR (TOKAMAK Fusion Test Reactor) are described.
Vibration effects of the space shuttle main engine high pressure oxidizer turbopump bellows
A welded metal bellows was subjected to a series of vibration tests in a 400 psi oxygen environment to evaluate the effects of the bellows convolutes rubbing on the damper ring in the high pressure oxidizer ...
Stability of bellows used as expansion joints between superconducting magnets in accelerators
1991-01-01
For superconducting magnets, one needs many bellows for connection of various helium cooling transfer lines. There could be approximately 20,000 magnet interconnection bellows in the SSC exposed to an internal pressure. When axially compressed, internally pressurized, or insufficiently supported at their ends, bellows can become unstable, leading to gross distortion or complete failure. If several bellows are contained in a magnet assembly, failure modes might interact. If designed properly large bellows can be used to connect the large tubular shells that support the magnet iron yokes and superconducting coils and contain supercritical helium for magnet cooling. We investigate here bellows design features and end supports to insure that instabilities will not occur in the bellows pressure operating region, including some margin. A model of three superconducting accelerator magnets connected by two large bellows is analyzed in order to ascertain that support requirements are satisfied and in order to study interaction effects between the two bellows. Specific details of large and small bellows design and reliability for our application will be addressed.
1990-01-01
For superconducting magnets, one needs many bellows for connection of various helium cooling transfer lines in addition to beam tube bellows. There could be approximately 10,000 magnet interconnection bellows in the SSC exposed to an internal pressure. When axially compressed or internally pressurized, bellows can become unstable, leading to gross distortion or complete failure. If several bellows are contained in an assembly, failure modes might interact. If designed properly, large bellows can be a very feasible possibility for connecting the large tubular shells that support the magnet iron yokes and superconducting coils and contain supercritical helium for magnet cooling. We present here (1) a spring-supported bellows model, in order to develop necessary design features for bellows and end supports so that instabilities will not occur in the bellows pressure operating region, including some margin, (2) a model of three superconducting accelerator magnets connected by two large bellows, in order to ascertain that support requirements are satisfied and in order to study interaction effects between the two bellows. Reliability of bellows for our application will be stressed. 3 refs., 4 figs.
The consequences of expansion joint bellows failure
1993-08-01
Expansion joint (EJ) bellows are thin walled, flexible components of a piping system. As such, they usually are the weakest structural link in the pressure boundary from a failure probability perspective. Previously, a 360{degrees}, circumferential rupture of a bellows was conservatively assumed to cause bellows collapse due to internal pressure resulting in a double-ended guillotine break (DEGB) and the associated, large leak rate. A finite element analysis was performed to determine the structural response of a ruptured bellows and its ability to resist large opening areas and hence, large leak rates. The results show that a 360{degrees} break can lead to an opening width of up to 0.7 inch following an instantaneous rupture -- provided the equalizing rings and tie rods remain intact. This would result in an initial leak rate reduction equal to 80% of the previously assumed DEGB flow. The reduced flow rate is less than the water removal system capacity-assuring that flooding will not occur.
Consequences of expansion joint bellows rupture
1992-01-01
Expansion joints are used in piping systems to accommodate pipe deflections during service and to facilitate fitup. Typically, the expansion joint bellows is the thinnest part of the pressure boundary, bellows rupture frequencies are typically several orders of magnitude higher than pipe rupture frequencies. This paper reviews an effort to estimate the flow rates associated with bellows rupture. The Level I PRA (probabilistic risk assessment) for the Savannah River Site production reactors made the bounding assumption that bellows rupture would produce the maximum possible leakage - that of a double-ended guillotine break (DEGB). This assumption resulted in predictions of flooding of the reactor building with a high conditional probability that a Loss of Pumping Accident and core melting would follow. This paper describes analyses that were performed to develop a realistic break area and leak rate resulting from bellows rupture and therefore reduce the impact that bellows rupture can have on the estimated total core melt frequency. In the event of a 360 degree circumferential break of the bellows the resulting two sections will separate to the point where the force from the internal pressure acting to push the bellows open is just balanced by the spring force of the bellows itself. For the bellows addressed in this analysis, the equilibrium separation distance is 0.7 inches with normal pump lineup. The opening area is influenced by any initial compression or extension due to installation alignment, and by any operational displacements such as thermal expansion of the adjoining pipe. The influence of such factors is considered and the impact on the flooding rate and, hence, core melt frequency is reviewed.
Consequences of expansion joint bellows rupture
1992-11-01
Expansion joints are used in piping systems to accommodate pipe deflections during service and to facilitate fitup. Typically, the expansion joint bellows is the thinnest part of the pressure boundary, bellows rupture frequencies are typically several orders of magnitude higher than pipe rupture frequencies. This paper reviews an effort to estimate the flow rates associated with bellows rupture. The Level I PRA (probabilistic risk assessment) for the Savannah River Site production reactors made the bounding assumption that bellows rupture would produce the maximum possible leakage - that of a double-ended guillotine break (DEGB). This assumption resulted in predictions of flooding of the reactor building with a high conditional probability that a Loss of Pumping Accident and core melting would follow. This paper describes analyses that were performed to develop a realistic break area and leak rate resulting from bellows rupture and therefore reduce the impact that bellows rupture can have on the estimated total core melt frequency. In the event of a 360 degree circumferential break of the bellows the resulting two sections will separate to the point where the force from the internal pressure acting to push the bellows open is just balanced by the spring force of the bellows itself. For the bellows addressed in this analysis, the equilibrium separation distance is 0.7 inches with normal pump lineup. The opening area is influenced by any initial compression or extension due to installation alignment, and by any operational displacements such as thermal expansion of the adjoining pipe. The influence of such factors is considered and the impact on the flooding rate and, hence, core melt frequency is reviewed.
Modelling Flexible Bellows by Standard Beam Finite Elements
A procedure for modelling flexible metal bellows by the standard beam finite elements in I-DEAS Master Series 6 is presented. In spite of the geometry of the bellows being far from a beam, it is sho ... Full Text Available
Digital Repository Infrastructure Vision for European Research (DRIVER)
Failure of expansion joint tie rods -- Impact on bellows integrity
1992-01-01
Expansion joints are used in piping systems to accomodate pipe deflections during service and to facilitate fitup. Often, tie rods are employed to limit the range of axial deflection. Additional restraint against excessive displacement can be provided by the surrounding pipe and associated supports. This paper presents a methodology that was employed to estimate the consequences of tie rod failure. Of particular interest is whether tie rod failure can lead to sufficient displacement as to cause bellows rupture.
Failure of expansion joint tie rods -- Impact on bellows integrity
1992-12-31
Expansion joints are used in piping systems to accomodate pipe deflections during service and to facilitate fitup. Often, tie rods are employed to limit the range of axial deflection. Additional restraint against excessive displacement can be provided by the surrounding pipe and associated supports. This paper presents a methodology that was employed to estimate the consequences of tie rod failure. Of particular interest is whether tie rod failure can lead to sufficient displacement as to cause bellows rupture.
Optimal Pressure Regulation of the Pneumatic Ventricular Assist Device With Bellows-Type Driver
2009-01-01
Abstract The bellows-type pneumatic ventricular assist device (VAD) generates pneumatic pressure with compression of bellows instead of using an air compressor. This VAD driver has a small volume that is suitable for portable devices. However, improper pneumatic pressure setup can not only cause a lack of adequate flow generation, but also cause durability problems. In this study, a pneumatic pressure regulation system for optimal operation of the bellows-type VAD has been developed. The optimal pneumatic pressure conditions according to various afterload conditions aiming for optimal flow rates were investigated, and an afterload estimation algorithm was developed. The developed regulation system, which consists of a pressure sensor and a two-way solenoid valve, estimates the current afte...
1994-09-01
Bellows are an integral part of the containment pressure boundary in nuclear power plants. They are used at piping penetrations to allow relative movement between piping and the containment wall, while minimizing the load imposed on the piping and wall. Piping bellows are primarily used in steel containments; however, they have received limited use in some concrete (reinforced and prestressed) containments. In a severe accident they may be subjected to pressure and temperature conditions that exceed the design values, along with a combination of axial and lateral deflections. A test program to determine the leak-tight capacity of containment penetration bellows is being conducted under the sponsorship of the US Nuclear Regulatory Commission at Sandia National Laboratories. Several different bellows geometries, representative of actual containment bellows, have been subjected to extreme deflections along with pressure and temperature loads. The bellows geometries and loading conditions are described along with the testing apparatus and procedures. A total of thirteen bellows have been tested, all in the `like-new` condition. (Additional tests are planned of bellows that have been subjected to corrosion.) The tests showed that bellows are capable of withstanding relatively large deformations, up to, or near, the point of full compression or elongation, before developing leakage. The test data is presented and discussed.
1995-10-01
Bellows are an integral part of the containment pressure boundary in nuclear power plants. They are used at piping penetrations to allow relative movement between piping and the containment wall, while minimizing the load imposed on the piping and wall. Piping bellows are primarily used in steel containments; however, they have received limited use in some concrete (reinforced and prestressed) containments. In a severe accident they may be subjected to pressure and temperature conditions that exceed the design values, along with a combination of axial and lateral deflections. A test program to determine the leak-tight capacity of containment penetration bellows is being conducted at Sandia National Laboratories under the sponsorship of the US Nuclear Regulatory Commission. Several different bellows geometries, representative of actual containment bellows, have been subjected to extreme deflections along with pressure and temperature loads. The bellows geometries and loading conditions are described along with the testing apparatus and procedures. A total of nineteen bellows have been tested. Thirteen bellows were tested in ``like-new`` condition (results reported in Volume 1), and six were tested in a corroded condition. The tests showed that bellows in ``like-new`` condition are capable of withstanding relatively large deformations, up to, or near, the point of full compression or elongation, before developing leakage, while those in a corroded condition did not perform as well, depending on the amount of corrosion. The corroded bellows test program and results are presented in this report.
Long-Term Life of Ni/Cu Bellows: Effect of Diffusion on Thermomechanical Properties
The aim of this paper is to discuss different couplings between diffusion, re- crystallisation/grain growth, strain/stress, heat transfer and thermo-mechanical behaviour of metallic materials. The und ... Full Text Available
Digital Repository Infrastructure Vision for European Research (DRIVER)
Piping instability resulting from bellows misalignment
1989-05-30
The failure of the single phase bellows and magnet test stand during quench testing of SSC dipole magnet DD0011 has led to much speculation about the inherent stability of operating SSC magnets. This note addresses the problem of instabilities resulting from both translational and angular misalignment between pipes connected by bellows in the general sense and with respect to the SSC single phase system specifically. Note that none of the instabilities referenced here result from bellows 'squirm'. Inelastic bellows failure is not within the scope of this work. The failure mode referenced here is an elastic instability. 3 refs., 7 figs.
Estimate of the contributions of bellows to the impedances and beam instabilities of the SSC
1985-07-01
Between sections of the vacuum chamber, bellows are needed to compensate for thermal expansion and transverse offsets. For beampipe made of stainless steel with a coefficient of linear expansion 19 x 10/sup -6///sup 0/C and a temperature variation of approx.316/sup 0/C, the allowance for bellows is approx.1.2% of the total length of the beampipe, if we assume that the bellows are 50% compressible. This implies 1.08 km of bellows for Design A of the SSC which has a circumference of 90 km. Such a length of bellows will certainly contribute to the longitudinal and transverse impedances of the accelerator and will therefore affect the stability of the beam. In the Reference Designs, the actual impedances of the bellows have not been calculated; only an allowance of Z/sub parallel//n = 0.05 ..cap omega.. and Z/sub perpendicular/ = 7 M..cap omega../m is made for miscellaneous discontinuities because all the bellows and pumping ports are assumed totally shielded. It is the purpose of this article to examine the actual contributions by the bellows to the longitudinal and transverse impedances assuming that they are not shielded.
1994-09-01
Containment piping penetration bellows are an integral part of the pressure boundary in steel containments in the United States (US). Their purpose is to minimize loading on the containment shell caused by differential movement between the piping and the containment. This differential movement is typically caused by thermal gradients generated during startup and shutdown of the reactor, but can be caused by earthquake, a loss-of-coolant accident (LOCA), or ``severe`` accidents. In the event of a severe accident, the bellows would be subjected to pressure, temperature, and deflection well beyond the design basis. Most bellows are installed such that they would be subjected to elevated internal pressure, elevated temperature, axial compression, and lateral deflection during a severe accident. A few bellows would be subjected to external pressure and axial elongation, as well as elevated temperature and lateral deflection. The purpose of this experimental program is to examine the potential for leakage of containment bellows during a severe accident. The test series subjects bellows to various levels and combinations of internal pressure, elevated temperature, axial compression or elongation, and lateral deformation. The experiments are being conducted in two parts. For Part 1, all bellows specimens are tested in ``like-new`` condition, without regard for the possible degrading effect of corrosion that has been observed in some containment piping bellows in the US Part I testing, which included 13 bellows tests, has been completed. The second part of the experimental program, in which bellows are subjected to simulated corrosive environments prior to testing, has just just begun. The Part I experiments have shown that bellows in ``like-new`` condition can withstand elevated temperatures and pressures along with large deformations before leaking. In most cases, the like-new bellows were fully compressed without developing any leakage.
Influence of Micro-Damage on Reliability of Cryogenic Bellows in the LHC Interconnections
2007-12-01
To achieve maximum beam energy in the LHC the accumulated length of the interconnections between LHC main magnets has been limited to around 3% of the total magnetic length in the Arcs and Dispersion Suppressors. Such a low ratio leads to a very compact design of components located in the LHC interconnections. This implies development and evolution of high intensity plastic strain fields in the stainless steel expansion bellows subjected to thermo-mechanical loads at low temperatures. These components have been optimised to ensure high reliability standards required for the LHC. Nevertheless, initial damage can occur and lead to a premature fatigue failure. For structures in which plasticity is not confined to the crack tip region, standard failure mechanics, based classically on the stress intensity factor or the strain energy density release rate, can not be used. In the present paper, a constitutive model taking into account plastic strain induced g->a' phase transformation and orthotropic ductile damage is presented. This local approach is used to predict the impact of initial imperfections on the fatigue life of thin-walled LHC bellows expansion joints.
Application of comb-type RF shield to bellows chambers and gate valves
2005-01-01
A comb-type RF shield has been applied to bellows chambers and gate valves in a chain of R and D for future high intensity accelerators. The comb-type RF shield has a structure of nested comb teeth, and has higher thermal strength and lower impedance than the conventional finger-type one. Various types of seven bellows chambers have been installed in the KEK B-Factory (KEKB) positron ring since 2003 in series. The temperature of the bellows corrugation decreased by a factor of 3-6 in most cases. No significant problem has been found in these bellows chamber up to a stored beam current of 1.8 A (1.3 mA/bunch). A circular-type gate valve with the comb-type RF shield was also installed in the positron ring in January 2005 and promising results were obtained. (author)
Experiments to evaluate behavior of containment piping bellows under severe accident conditions
1993-11-01
Bellows are an integral part of the containment pressure boundary in nuclear power plants. They are used at piping penetrations to allow relative movement between piping and the containment wall. In a severe accident they may be subjected to high pressure and temperature, and a combination of axial and lateral deflections. A test program to determine the leak-tight capacity of containment penetration bellows is being conducted at Sandia National Laboratories, Albuquerque, New Mexico. Several different bellows geometries, representative of actual containment bellows, are being subjected to extreme deflections along with pressure and temperature loads. The bellows geometries and loading conditions are described along with the testing apparatus and procedures. A total of thirteen tests have been conducted. The tests showed that withstanding relatively large bellows are capable of deformations, up to, or near, the point of full compression before developing leakage. The test data is presented and discussed.
2007-01-01
A consistent feature of Saul Bellow’s fiction is the protagonist’s encounter with one or more teaching figures. Dialogue with such individuals prompts the Bellovian protagonist to reject his current state of selfhood as inadequate and provokes him to re-form as a new person. The teacher figure offers a better self to which the protagonist is attracted; or, more frequently in Bellow, the protagonist is repelled by both his teacher and his own current state to form a new, previously unrepresented self. This thesis argues that Bellow’s self inherits and modifies the perfectionist philosophy of Ralph Waldo Emerson and Henry David Thoreau, in a literary reinterpretation that parallels Stanley Cavell’s philosophical revaluation of the American Transcendentalists. In Emerson and Thoreau, and in Cavell’s reading of perfectionism, the self is attracted onward only by a better representation of selfhood in another, while Bellow’s self may also be, and often is, provoked by a repellent other to inhabit a new form of selfhood. This thesis takes the evolution of selfhood in Bellow to be structured by travel. In The Adventures of Augie March, Augie’s movement between selves is impelled by conversation with teacher figures and paralleled by his unending journeys. In Herzog, Herzog’s self-transformations and travels are provoked by reading and writing, and by the ecstasy of loss revealed to him through apostrophic conversations with the dead and absent in a series of unsent and mental letters. Letter-writing, the provocation for Herzog’s self-perfection, becomes a form of travel in Herzog. This thesis further argues that Bellow’s travelling self is a critical response to two poles of modern subjectivity, structured by European mythologies of travel: Bellow’s fiction is critical, first, of a Hegelian, egoist mode of selfhood structured after the Odyssey; but equally critical of examples of Levinasian openness to the Other, patterned on Abraham’s exile. Bellow does not accept either the Odyssean or the Abrahamic mode of selfhood on its own, recognizing oppressive possibilities in both. Travelling selfhood in Bellow, initiated by conversation with others, both fuses and rereads Odyssean and Abrahamic constructs within a new, but perpetually unfinished American mode of selfperfection.
1983-03-08
A liquid level system employs a pair of vertically spaced sensors in a tank such as a boiler. Each sensor includes a pair of bellows. The first bellows is enclosed by a protective enclosure while the second bellows is exposed to the interior of the tank. The first bellows of the two sensors are interconnected and filled with a liquid forming substance, such as an alkali metal, which is in liquid phase at high temperatures, while the second bellows of each sensor and the enclosure for the first bellows are interconnected and filled with a second liquidforming substance, such as a metal alloy, which is essentially inert. A transducer is connected to one of the second bellows which produces an electrical output signal proportional to the difference between the pressures at the locations of the second bellows and, thus, the level of liquid in the tank.
Linear Actuator Has Long Stroke and High Resolution
... an oil bath within hermetically sealed bellows. The outer end of the bellows holds the outer end of the ball screw, thereby preventing rotation of the ball screw. Positioning is ...
Experiments on the Wavemaking of a Drifting Ship
Experiments on the Wavemaking of a Drifting Ship Full Text Available
Digital Repository Infrastructure Vision for European Research (DRIVER)
... ice that formed on the liquid-oxygen bellows running down the outside of the External Tank could break free during launch and hit this sensitive area. A Center Director s Discretionary Fund ...
Replica-based Crack Inspection
... of liquid hydrogen over gimble joint bellows, and consist of two rings each containing 38 elongated slots. In the summer of 2002, multiple cracks ranging from 0.1 inches to 0.6 inches long ...
The Dehn invariants of the Bricard octahedra
2009-01-21
We prove that the Dehn invariants of any Bricard octahedron remain constant during the flex and that the Strong Bellows Conjecture holds true for the Steffen flexible polyhedron.
Experimental and Numerical Investigations of Cryogenic Multiphase Flow
... loops. The end stacks contain metal bellows pumps, each with a volume displacement of one liter and controlled by linear stepper motors. These components can force the liquid cryogens to ...
DESIGN AND OPERATING EXPERIENCE ON LASER CAVITY IN A VACUUM OF 10-10 TORR
The length of the A.C.O. storage ring laser is 5.50 meters, on each side of the undulator is a vacuum system monted with bellows in which the laser cavity mirrors are placed. The mechanical feed thoug ... Full Text Available
Digital Repository Infrastructure Vision for European Research (DRIVER)
The attractiveness of three trap types to Bemisia tabaci (Gennadius) B-biotype (= Bemisia argentifolii Bellows & Perring) and Eretmocerus mundus Mercet adult was compared in two choice experiments in ... Full Text Available
Digital Repository Infrastructure Vision for European Research (DRIVER)
A method to determine methylmethacrylate in air.
1988-01-01
To determine the air concentrations of methylmethacrylate monomer and thus obtain information about the safety in the operating theater, a methylmethacrylate Dräger tube was used in connection with a bellows pump. This method gives an instantly readable value correlated with more complicated gas chromatographic measurements.
Flexible suspensions with a hexagonal equator
2009-05-25
We construct a flexible (non immersed) suspension with a hexagonal equator in Euclidean 3-space and study its properties related to the Strong Bellows Conjecture which reads as follows: if an immersed polyhedron $\Cal P$ in Euclidean 3-space is obtained from another immersed polyhedron $\Cal Q$ by a continuous flex then $\Cal P$ and $\Cal Q$ are scissors congruent.
2008-01-01
The (p, rho, T, x) properties for left bracexNH3 + (1 - x)H2Oright brace with x = (0.1048, 0.2046, 0.3807, 0.5565, 0.7008, 0.8010, 0.9102, and 1.0000) in the compressed liquid phase were measured by means of a metal-bellows variable volumometer at temperatures of (450 and 500) K and pressures from (10 to 200) MPa. The volume fraction purities of the ammonia used in the measurements were 0.99999. The water employed was deionised, distilled, and degassed to 3.0 approx = 10-4 Pa by freeze-thaw cycling with liquid nitrogen before use. In order to carry out these measurements at higher ranges of temperature (above T = 450 K) and pressure (up to p = 200 MPa), we have implemented several reconstructions to the apparatus, including the replacement of the sample cell containing the metal-bellows, and the ... >>
Response Specificity to Advertisement Vocalization in the Chinese Alligator (Alligator sinensis)
2009-01-01
Abstract Stringency in the identification of conspecific call properties is essential among sympatric species to ensure conspecific mating, as the risk of improper recognition and heterospecific mating is high. In this study we investigated the basic signal structure required for intraspecies communication in the Chinese alligator (Alligator sinensis), a species that has no relatives living in sympatry, by playback of signals modified in the temporal (truncating original bellows with first 1/4, 1/2, 3/4 or last 1/4, 1/2, 3/4 portion) or frequency domain (with low- or high-pass filters at frequencies 100, 250, 500 and 1000 Hz), or by reversal of natural bellows. The playback experiments revealed that relatively large modifications in bellow temporal or frequency structure failed to impair C...
2009-02-19
$$bAll replacement magnets required for Sectors 3-4, 1-2 and 6-7 have now been cryostated. Work is continuing to cryostat six additional spare dipoles as a precautionary measure. In the tunnel work is well underway to open the W bellows - the large bellows between the magnets - in order to start cutting and welding work for installation of the new pressure release ports. In Sector 3-4 the campaign to repair the damaged ‘QRL jumpers’ is going ahead. The QRL line is the network of cryogenics piping that distributes the liquid helium throughout the tunnel. Every 100 m the distribution line is connected to the magnets through pipes known as ‘jumpers’. During the incident in Sector 3-4 last September, four ‘jumpers’ were damaged. One has now been completely repaired and the remaining three jumpers are currently being repaired and should be completed at a rate of one per week. The replacement magnet for the faulty dipole removed from Sector 1-2 has now been installed in the tunnel. Surveyors have checked the alignment and the interconnection work has already started.
Stereo-photogrammetric mapping of tooth replicas incorporating texture
2005-01-01
Commercial digital photogrammetric software has been applied to convergent stereoscopic photography of human tooth replicas prepared to exhibit optical texture resulting in successful generation of 3D coordinate data. Tooth replicas were imaged using a semi-metric 35 mm camera and f = 100 mm macro lens on extension bellows. Model precision was within acceptable limits of 12 μm or better for manual target matching and 21 μm or better for automatic image matching. Further improvement in optical texture is required to achieve automatic image matching precision comparable to that of manual target matching. Small errors in interior orientation parameters attributed to instability in the bellows as well as small errors in the relative orientation resulted in some systematic errors. The use of a fixed camera lens system is expected to reduce these errors. When combined with commercially available, moderately priced, digital SLR cameras this brings 3D model generation closer to everyday clinical dental practice.
Development of foil charge stripping system for RCS of J-PARC
2005-01-01
We have designed the charge stripping device for 3-GeV RCS of J-PARC. This device consists of 3 parts. The H- beam from linac is converted into H+ beam by the first stripping foil. The H0 and H- beam not converted by the first stripping foil is converted into H+ beam by the second and the third stripping foils. The driving mechanism is operated by the transfer-rod. By using these devices, it results in the length of about 2/3 and lightening, compared with system used bellows. (author)
Erotic Literature in Nineteenth-Century Bali
2002-01-01
Two nineteenth-century Balinese genres in which the erotic predominates are epic kakawin poetry and tutur (religious manuals) on sexual yoga. The article points to the strong intertextual links between these diverse genres. Through their focus on practical sexual matters and on the pursuit of sexual pleasure as integral to spiritual growth, tutur and kakawin also offer insight into notions of gender and sexuality in nineteenth-century Bali.
DAFNE Interaction Regions upgrade
2008-03-11
DAFNE, the Frascati F-factory, has recently completed experimental runs for the three main detectors, KLOE, FINUDA and DEAR achieving 1.6x10E+32 cm-2s-1 peak and 10 pb-1 daily integrated luminosities. Improving these results by a significant factor requires changing the collision scheme. For this reason, in view of the SIDDHARTA detector installation, relevant modifications of the machine have been realized, aimed at implementing a new collision scheme based on a large Piwinski angle and crab-waist, together with several other hardware modifications involving injection kickers, bellows and beam pipe sections.
Vacuum system - how to get ready for beam ?
During the incident of sector 3-4, the two beam vacuum sectors of 2.8 km each and four insulation vacuum sectors i.e. 750 m were vented to atmospheric pressure. Besides the mechanical damages of the nested bellows and plug-in-modules due to the mouvement of the cold masses under the helium pressure, soot and debris of superinsulation were spread inside the beam and insulation vacua. The presentation will cover the extend of the damage from Q6R3 till Q6L4. The strategy deployed to repair, to clean and to qualify the damaged vacuum systems will be discussed. Scheduling and compatibilty with beam operation issues will be also adressed.
The short interconnect length between the LHC superconducting magnets required the development of an optimised RF shielded bellows module, with a low impedance combined with compensation for large thermal displacements and alignment lateral offsets. Each bellows is shielded by slender copper-beryllium fingers working as preloaded beams in order to provide a constant force at the sliding contact. Unless the sliding friction and some geometrical parameters of the fingers are kept within a limited range, a large irreversible lateral deflection towards the vacuum chamber axis may occur and eventually block the beam aperture. The finite element analysis presented here simulates this failure mechanism, providing a complete understanding of the finger behaviour as well as the influence of the various design parameters. An implicit nonlinear two-dimensional model integrating friction on the sliding contacts, geometrical non-linearity and plasticity was implemented in a first stage. The design was then verified through the whole working range using an explicit formulation, which overcame the instabilities resulting from the sudden release of internal energy stored in the finger.
2009-01-01
For the operation of accelerators it is important that motions in the vacuum occur. The here produced diploma thesis deals with the possibility to perform thes motions with piezocrystal motors in order to abandon wear-susceptible membrane bellows. For this studies have been performed, which should show for which it is useful to apply a piezocrystal motor. Limits are shown, advances and disadvantages are weighted in the thesis. Construction with with subsequent test of a tandem facility and an outlook on possible future concepts form the main content
War and local collective action in Sierra Leone
2009-01-01
We study the brutal 1991-2002 Sierra Leone civil war using nationally representative household data on conflict experiences, postwar economic outcomes, local politics and collective action. Individuals whose households directly experienced more intense war violence are robustly more likely to attend community meetings, more likely to join local political and community groups, and more likely to vote. Tests using prewar controls and alternative samples suggest that selection into victimization is unlikely to be driving the results. More speculatively, the findings could help partially explain the rapid postwar political and economic recoveries observed in Sierra Leone and after several other recent African civil wars.
Proton pump inhibitors: actions and reactions
2009-01-01
Proton pump inhibitors are the second most commonly prescribed drug class in the United States. The increased utilization of PPIs parallels the rising incidence of reflux disease. Owing to their clinical efficacy and relative lack of tachyphylaxis, PPIs have largely displaced H-2 receptor antagonists in the treatment of acid peptic disorders. The elevation of intragastric pH and subsequent alterations of gastric physiology induced by PPIs may yield undesired effects within the upper GI tract. The ubiquity of the various types of H+, K+-ATPase could also contribute to non-gastric effects. PPIs may influence physiology in other ways, such as inducing transepithelial leak.
Chemical sensing underclothing system for testing PPE
2009-01-01
Personal protective equipment (PPE) when worn is subjected to pressure differentials across the garment due to ambient wind flow, by body movement and breathing creating the bellows effect, which may force hazardous chemicals vapor or aerosol through the closures, joints, outlet valves and/or clothing protective fabric. Thus the design, fit, size or improper donning of the protective garment will influence chemical-agent penetration. In order to determine penetration of chemical-protective garments by chemical vapor or aerosol, it is necessary to test the entire suit system, including seams, closures, outlet valves and areas of transition with other protective equipment, that is, at the ankles, waist, wrists, neck etc. In order to identify penetration of chemical vapor or aerosol through protective assembly, the Man-in-Simulant Test (MIST) with passive adsorptive ... >>
2007-01-01
Female koalas (Phascolarctos cinereus) exhibit both homosexual and heterosexual interactions in captivity, even though only heterosexual copulations have been observed in the wild. A key component of sexual interaction is the acoustic bellow, which is produced by males in the wild and both females and males in captivity. We recorded events in both homosexual and heterosexual interactions in a captive koala population, and vocalisations during and outside these interactions. A total of 43 homosexual and 15 heterosexual interactions were recorded in female koalas and were found to have the same principle components following presentation of the mounting male or female to the female: a short delay from neckbite to thrusting, a thrusting phase, followed by a pause and finally jerking behaviour. Thrusting and jerking phases were longest and were of approximately equal length. The delay from neckbite to thrusting, the thrusting phase and the jerking phase were shorter in homosexual than heterosexual mountings, which may relate to the absence of penile intromission and ejaculation. Female koalas exhibited characteristic oestrous and rejection vocalisations that may attract partners or result in them being rejected. The female post-mating calls and calls outside oestrus were longest, followed by female oestrous bellows and male calls, with female rejection calls being the shortest. Rejection calls were higher frequency than the oestrous calls, in particular rejection of a female. Following separation of bellow acoustics into a grunt and a shorter inhalation component, female bellows could be successfully discriminated from male bellows for 64% of the grunt phases, and 71% of the inhalation phases (P < 0.001). Most of the variation between individuals was in the duration, rather than the harmonic range, starting or mean frequency, which were similar for both homosexual and heterosexual copulations. It is concluded that homosexual and heterosexual interactions in female koalas contain the same behavioural components, and similar accompanying vocalisations, although the duration of the different components is specific to the gender and stage of copulation. (c) 2006 Elsevier B.V. All rights reserved.
Tropes, Materiality, and Ritual Embodiment of African Iron Smelting Furnaces as Human Figures
2009-01-01
The largest baked clay figure in Africa is an iron smelting furnace. Clay breasts, vaginal openings, testicle-like bellows, and penis-like blow pipes are part of a culturally constructed reproductive system using the female body and parts of the male anatomy. Ritual embodiments using potent tropes, body gestures, and sounds transform furnaces into human bodies. Anthropological representations have long examined only female fecundity and misrepresented reproductive processes such as menses. Thick description of ritual expressions, however, sheds new light on previously dichotomous categories of male and female in iron smelting and creates a more complete understanding of the materiality of the female body in baked clay furnaces.
An inchworm mobile robot using electromagnetic linear actuator
2009-01-01
The capability of motion is one of the important aspects for a micro-robot to fulfill its given tasks. Micro-autonomous systems usually require large force, large displacement and less power consumption. Among different actuation schemes, electromagnetic actuator shows the benefit in a combination of force, displacement and cost effective control. A bristle-based inchworm mobile robot using a short stroke electromagnetic linear actuator is described in the paper. The main body and movable unit of the robot are joined by using a sealed bellows and the bristle legs are designed so that it can operate both on plane surfaces and in liquid. The actuator designed for the robot is a tubular type linear machine with an overall size of 7x10mm. The key dimensions of the actuator were determined thro...
2008-01-01
Tore supra (TS) in vessel components represent a unique combination of metals in the hydraulic circuit. Different materials, e.g. stainless steel, copper alloys, nickel, etc., were joined together by fusion welding, brazing and friction. Since the operation and baking temperature of all in vessel components has been defined to be set at 230 deg. C/40 bars a special water chemistry of the cooling water loop was suggested in order to prevent eventual water leaks due to corrosion at relative high temperatures and pressures in tubes, bellows, coils and coolant plant ancillary equipments. Following experiences with water chemistry in Pressurised Water Reactors, an all volatile chemical treatment (AVT) has been defined for the cooling water quality of TS. Since then, a simplified static (no fluid circulation) corrosion test program at relatively high temperature and pressure ... >>
Development of Tc-99 Characterization Approach for the Portsmouth Gaseous Diffusion Plant
2006-01-01
A methodology to non-invasively characterize the Tc-99 inside the equipment at the Portsmouth Gaseous Diffusion Plant was developed. The sensitivity of the approach was examined through critical benchmarking measurements and computer simulations. From comparison of these measurements and computer simulations, uncertainties in the methodology were established. The study results have shown that, given simplified geometries of pipe wall and deposit materials, the Tc-99 Bremsstrahlung can be used to characterize the level of contamination of Tc-99 in a uranium deposit assuming uniform distribution of Tc-99 in the deposit. The sensitivity of the approach is adequate to address worker safety limits based on calculations from the derived air concentrations. It is anticipated that the technique will be most successful in thin-walled containers, such as aluminum bellows ... >>
2008-01-01
In the present study, the effect of disruptions on beryllium has been studied. Disruptions are simulated in the electron beam facility JUDITH by high energetic pulses of up to 250 MJ/m2. Under these loads, the beryllium surface may roughen combined with the forming of cracks. During the experiments, a special problem arises from the fact that during the neutron irradiation beryllium transmutes to tritium. This tritium is bound in the beryllium matrix, but during the heating of the samples, the tritium may be set free and through the vacuum pump it may be released to the environment. In order to avoid and to quantify this release of tritium, a special tritium trap has been constructed. In this tritium trap the gas is pumped by means of a metal bellows pump through a catalyst tube filled with copper oxide. At a temperature of 300 deg. C, the tritium is oxidized to HTO. This HTO is ... >>
2009-01-01
Abstract Trap cropping, though promising, has had little evaluation in greenhouses. This study evaluated eggplant, Solanum melongena L. (Solanaceae), as a trap crop for two whitefly species, Trialeurodes vaporariorum (Westwood) and Bemisia argentifolii Bellows &Perring (both Hemiptera: Aleyrodidae), on greenhouse poinsettia, Euphorbia pulcherrima Willd. ex Koltz (Euphorbiaceae). Because the two whitefly species co-occur in greenhouses, a common trap crop for both whiteflies is desirable. When adults were provided a choice between eggplant and poinsettia in a cage, 60% of B. argentifolii and 98% of T. vaporariorum were observed on eggplant after 3 days. However, when adults were given eggplant after first settling on poinsettia, only 38% of B. argentifolii were later found on eggplant, wher...
2009-01-01
Microdeletion at chromosomal position 15q13.3 has been described in intellectual disability, autism spectrum disorders, schizophrenia and recently in idiopathic generalized epilepsy (IGE). Using independent IGE cohorts, we first aimed to confirm the association of 15q13.3 deletions and IGE. We then set out to determine the relative occurrence of sporadic and familial cases and to examine the likelihood of having seizures for individuals with the microdeletion in familial cases. The 15q13.3 microdeletion was identified in 7 of 539 (1.3%) unrelated cases of IGE using quantitative PCR or SNP arrays and confirmed by array comparative genomic hybridization analysis using probes specific to the 15q13.3 region. The inheritance of this lesion was tracked using family studies. Of the seven microdel...
Success in the pipeline for CMS
2008-06-19
$$bThe very heart of any LHC experiment is not a pixel detector, nor a vertex locator but a beam pipe. It is the site of each collision and the boundary where the accelerator and experiment meet. As an element of complex design and manufacture the CMS beam pipe was fifteen years in the making and finally fully installed on Tuesday 10 June. Watch the video! End cap beam pipe installation in the CMS detector. Central beam pipe installation.The compensation modules were the final pieces to take their places in the cavern at Point 5: "These are like bellows," says Wolfram Zeuner, Deputy Technical Co-ordinator for CMS. "They allow us to compensate for the change in length when we heat or cool the beam pipe. And they are the very last elements; beam pipe installation, which began last year, is now complete." The beam pipe is neither too fragile nor too bulky, but just right to satisfy the conflicting needs of the machine and detector. "For the machine the thicker the better because if it were to break that would halt the entire LHC," explains Patrick Lepeule, the engineer responsible for the pipe’s design and installation. "And the beam has such high energy that instability of the vacuum is a real concern." On top of this, a more solid pipe gives better electrical conductivity. However, the detector has very different priorities: "For CMS the ideal pipe is a transparent wall that particles can pass through without interacting. The experiment wants no material, no support, and virtually nothing at the collision point! We had to work through all these requirements and in the end there was a compromise," says Patrick. Designers of the CMS beam pipe also faced the additional challenge of creating a pipe that would allow for full opening of the detector. The compromise is a complex beam pipe made of sections of varying thickness and materials. For two metres either side of the interaction point the pipe is incredibly thin yet vacuum-tight, made from 0.8 mm of beryllium, a metal of low atomic number and weighing under 1.5kg. Beyond that for 18 metres on each side and widening towards the ends, are more solid sections of stainless steel, good for welding, assembly and precision alignment. Happy seeing the designs come to fruition, Patrick praises the installation team: "Nothing would have been possible without the availability and the professionalism of the team." "We all certainly had a few sleepless nights," adds Wolfram. "But beam pipe building is an art as well as a science, so it was worth it. This is a great achievement for all." The task of a beam pipe may seem simple but it is in fact a beautifully precise piece of machinery running through the very heart of another. (A full version of this article is available in the 9 June issue of the ‘CMS Times’).
2007-11-15
$$bTen years after the beginning of the project, the LHCb’s delicate VELO detector has been successfully installed in its final position. At the end of October, the very fragile VELO detector was carefully inserted into its vacuum tank. LHCb’s most fragile detector, the VELO, has been successfully installed in its final position. The first half was gently slid into place on 30 October and the second half followed on 31 October. For the LHCb collaboration, installing the Vertex Locator (VELO) detector into the VELO tank underground in the experimental cavern at CERN has been a challenging task. The VELO is a precise particle-tracking detector that surrounds the proton-proton collision point inside the LHCb experiment. At its heart are 84 half-moon shaped silicon sensors, each one connected to its electronics. The sensors, which are grouped in pairs to make a total of 42 modules, were constructed at Liverpool University. They will play a crucial role in detecting b quarks, the particles that will help to explain why matter and antimatter behave so differently. As it is placed extremely close to the beam line, the VELO must be radiation-hard and very precise in taking measurements. It will have to take trigger decisions about once per millisecond in order to select the interesting interactions that the LHCb experiment is designed to study at the LHC. "This is a defining moment for the VELO team," said Paula Collins, LHCb-VELO project leader. "For this to work we need all of the experts from the VELO side, as well as the mechanical and electrical experts for the LHC vacuum. There will be plenty of pumping down from atmospheric pressure and venting to bring the pressure up again, during which we will have to protect the silicon sensors and their fragile encapsulating foil. In order to have the ability to pick out the signal B decays from the background we also need to precisely align the two retractable halves during the insertion." The two halves, each consisting of 21 modules, were transported from their assembly room in Meyrin to the experimental site with a suite of custom-made lifting devices and transport trolleys, equipped with strong shock absorbers. They were then turned and inserted sideways into the VELO vacuum tank. Custom-made bellows were constructed which enable the VELO to retract to 35 mm and then move back to its original position of just 5 mm from the beam line. This flexibility is crucial during the stabilizing of the LHC beam. The silicon sensors measure the location of the beam and help to centre the VELO around it. The VELO is a unique detector that comprises a 110 cm section of the beam pipe. An aluminum sheet just 0.3 mm thick provides a shield between the silicon modules and the primary beam vacuum. This corrugated "foil", constructed by NIKHEF and the free University (Amsterdam), is designed with ridges which allow the two halves to overlap each other. There is not more than 1mm of leeway to the silicon modules. "It was very tricky, because we were blindly sliding in the detector," said Eddy Jans, VELO installation coordinator, "and as these modules are so fragile, we could have damaged them all and not realized it right away." Happily the verification procedures carried out on the silicon modules after installation indicated that no damage had occurred. The VELO project has been ongoing for the past 10 years. This milestone marks the moment at which the construction phase of the project has been brought successfully to fruition. As Collins sums up, "the VELO is now in place for physics".
Intermolecular interactions in aqueous binary mixtures of non-electrolytes
1995-01-01
The density and shear viscosity of mixtures of tert-Butyl alcohol (ButOH) and tert-Butylamine (ButNH2) with water have been determined for various temperatures (288.15 K to 318.15 K for H2O+ButOH and 288.15 K to 308.15 K for H2O+ButNH2) over the whole composition range. Excess molar volumes and apparent molar volumes of the components of each system were calculated from the density data. In both systems the apparent molar volume of the organic component passes through a minimum in the water-rich region. Both systems exhibit large negative excess molar volumes which are essentially independent of temperature at all compositions. The two systems show pronounced maxima in their shear viscosity isotherms. The empirical solvent polarity parameters ENR and ET for the solvatochromic compounds Nile Red and pyridinium-N-phenoxide betaine respectively, have been determined as a function of composition for water + tert-Butyl alcohol and water + tert-Butylamine binary mixtures, over the whole composition range at 298.15 K. For both systems the two parameters vary with composition in a strongly nonlinear fashion, and the polarity of the mixture decreases with increasing proportion of the organic cosolvent. The nonlinear variation of the polarity parameters is attributed to water-cosolvent hydrophobic interactions at low cosolvent contents, and hydrogen bonding interactions at higher cosolvent contents. Permittivity and refractive index have also been measured at 298.15 K for both systems, and both properties are strongly nonlinear functions of composition. The self-diffusion coefficients of water and of the organic component have been measured for H2O+t-butyl alcohol and H2O+t-butylamine mixtures over the whole composition range at 301.15 K, using the NMR spin-echo technique. In the water-rich region below 20 mole % of cosolvent, the self-diffusion coefficients of both components for each binary solvent system decrease rapidly with increasing cosolvent content. In cosolvent-rich mixtures with more than 50 mole % cosolvent, motions of water are evidently strongly correlated with those of cosolvent molecules. The semiempirical equation proposed by Albright relating the shear viscosity of a mixture to the diffusion coefficients of its components successfully predicts the general shape of the viscosity curve for each binary system. For the composition region above 50 mole % cosolvent the Albright equation gives calculated viscosities which agree well with observed values, but in the water-rich region there are significant deviations between the observed and calculated viscosities. Volume ratios have been measured with a bellows volumometer for t-Butylamine and six water + t-Butylamine mixtures at 278.15, 288.15, 298.15 and 313.15 K, at pressures up to about 200 MPa or at a lower pressure slightly below the freezing pressure at the temperature of measurement. From densities measured at 0.1 MPa together with the volume ratios at higher pressures, excess molar volumes, and isothermal compressibilities have been evaluated. The compressibility is a relatively simple function of pressure, temperature, and composition. Hydroxyl-proton chemical shifts for water and t-Butyl alcohol in water + t-Butyl alcohol mixtures with ≥8 mol% t-Butyl alcohol, and the averaged hydroxyl and amino proton chemical shift for water + t-Butylamine mixtures, have been determined at 200 MHz for four temperatures (263.15, 278.15, 298.15 and 313.15 K) as a function of composition. Further measurements have been made for water + t-Butyl alcohol + t-Butylamine ternary mixtures at 310.15 K over the complete mole fraction range at 60 MHz. Variations in solvent composition have little effect on the resonance for the methyl protons of the cosolvent, but the signal for the hydroxylic protons is substantially influenced. The water proton resonance initially shifts to higher frequencies (low fields) as the cosolvent is added to water, and the shift to higher frequency in the water proton resonance induced by the hydrophobic cosolvent is strongly temperature dependent, the effect being greatly enhanced at lower temperatures. As the proportion of cosolvent increases the hydroxyl proton signals in the water + t-Butyl alcohol system and the averaged proton signal in water + t-Butylamine mixtures shift to lower frequency (high field). Raman and FT-IR absorption spectra of aqueous t-Butyl alcohol and t-Butylamine in the region of O-H and NH2 stretching and bending modes have been measured at 298.15 K as a function of organic cosolvent concentration in the whole cosolvent mole fraction region. Vibrational intensities of some bands show definite trends with varying concentrations of the solutions. In the concentration dependence study unusual linewidth changes of certain bands were observed. Conductivities, densities and viscosity B-coefficients from the Jones-Dole equation were determined for NaI, KI, Bu4NI, LiCl and KCl at 298.15 K in various mixtures of water with t-Butyl alcohol and t-Butylamine. The limiting molar conductances and the corresponding Walden products have been computed. Values of the partial molar volumes of the electrolytes at infinite dilution in the various solvent mixtures were obtained from the density measurements.
Pointwise Convergence of Ergodic Averages in Orlicz Spaces
2009-02-27
We show that for each Orlicz space properly contained in L^q, where 1 is less than or equal to q, there is a sequence along which the ergodic averages converge for functions in the Orlicz space, but diverge for all f in L^q. This extends the work of K. Reinhold, who, building on the work of A. Bellow, constructed a sequence for which the averages converge a.e. for every f in L^p, p>1, but diverge for some f in L^1. Our method, introduced by Bellow and extended by Reinhold and M. Wierdl, is perturbation.
Yet another step in the completion of the Large Hadron Collider was taken yesterday morning, as the final element of the Compact Muon Solenoid was lowered nearly 100 meters bellow ground. After more than eight years of work at the world's most powerful particle accelerator, scientists hope that they will be able to start initial experiments with the LHC until the end of this year.
A pneumatic power harvesting ankle-foot orthosis to prevent foot-drop
Full Text Available.BackgroundA self-contained, self-controlled, pneumatic power harvesting ankle-foot orthosis (PhAFO) to manage foot-drop was developed and tested. Foot-drop is due to a disruption of the motor control pathway and may occur in numerous pathologies such as stroke, spinal cord injury, multiple sclerosis, and cerebral palsy. The objectives for the prototype PhAFO are to provide toe clearance during swing, permit free ankle motion during stance, and harvest the needed power with an underfoot bellow pump pressurized during the stance phase of walking.MethodsThe PhAFO was constructed from a two-part (tibia and foot) carbon composite structure with an articulating ankle joint. Ankle motion control was accomplished through a cam-follower locking mechanism actuated via a pneumatic circuit connected to the bellow pump and embedded in the foam sole. Biomechanical performance of the prototype orthosis was assessed during multiple trials of treadmill walking of an able-bodied control subject (n = 1). Motion capture and pressure measurements were used to investigate the effect of the PhAFO on lower limb joint behavior and the capacity of the bellow pump to repeatedly generate the required pneumatic pressure for toe clearance.ResultsToe clearance during swing was successfully achieved during all trials; average clearance 44 ± 5 mm. Free ankle motion was observed during stance and plantarflexion was blocked during swing. In addition, the bellow component repeatedly generated an average of 169 kPa per step of pressure during ten minutes of walking.ConclusionThis study demonstrated that fluid power could be harvested with a pneumatic circuit built into an AFO, and used to operate an actuated cam-lock mechanism that controls ankle-foot motion at specific periods of the gait cycle.
Infrared behaviour of propagator and quark confinement
2009-02-10
The propagator of confined quarks is calculated for timelike momenta by transforming Minkowski Greens functions to the Temporal Euclidean space. Based on the framework of the Schwinger-Dyson equations the QCD quark propagator is obtained in two approximations which differ by assuming behaviour of gluon propagator. In both studied cases we get universal result for the light quarks: The quark mass function becomes complex bellow expected perturbative threshold, the obtained absolute value of the infrared mass is $M\simeq \Lambda_{QCD} $ with the infrared phase $\simeq {\pi\over 2}$. Permanent confinement of quarks is maintained by generation of the complex mass function which prevents a real pole in the propagator. We will show that timelike dynamical Chiral Symmetry Breaking (CSB) solution is already approximately but non-trivially determined by the solution of gap equation in the standard Euclidean space.
The role of Stellar Feedback in the formation of galactic disks and bulges in a LCDM Universe
2007-10-10
Although supernova explosions and stellar winds happens at scales bellow 100 pc, they affect the interstellar medium(ISM) and galaxy formation. We use cosmological N-body+Hydrodynamics simulations of galaxy formation, as well as simulations of the ISM to study the effect of stellar feedback on galactic scales. Stellar feedback maintains gas with temperatures above a million degrees. This gas fills bubbles, super-bubbles and chimneys. Our model of feedback, in which 10%-30% of the feedback energy is coming from runaway stars, reproduces this hot gas only if the resolution is better than 50 pc. This is 10 times better than the typical resolution in cosmological simulations of galaxy formation. Only with this resolution, the effect of stellar feedback in galaxy formation is resolved without any assumption about sub-resolution physics. Stellar feedback can regulate the formation of bulges and can shape the inner parts of the rotation curve.
Piecewise Analytic Subactions for Analytic Dynamics
2009-04-23
We consider a piecewise analytic expanding map f: [0,1]-> [0,1] of degree d which preserves orientation, and an analytic positive potential g: [0,1] -> R. We address the analysis of the following problem: for a given analytic potential beta log g, where beta is a real constant, it is well known that there exists a real analytic (with a complex analytic extension to a small complex neighborhood of [0,1]) eigenfunction phi_beta for the Ruelle operator. One can ask: what happen with the function phi_beta, when beta goes to infinity. The domain of analyticity can change with beta. The correct question should be: is 1/ beta log phi_beta analytic in the limit, when beta goes to infinity ? Under a uniqueness assumption, this limit, when beta goes to infinity, is in fact a calibrated subaction V (see bellow definition). We show here that under certain conditions and for a certain class of generic potentials this continuous function is piecewise analytic (but not analytic). In a few examples one can get that the subaction is analytic (we need at least to assume that the maximizing probability has support in a unique fixed point).
A Ruelle Operator for continuous time Markov Chains
2008-03-18
We consider a generalization of the Ruelle theorem for the case of continuous time problems. We present a result which we believe is important for future use in problems in Mathematical Physics related to $C^*$-Algebras We consider a finite state set $S$ and a stationary continuous time Markov Chain $X_t$, $t\geq 0$, taking values on $S$. We denote by $\Omega$ the set of paths $w$ taking values on $S$ (the elements $w$ are locally constant with left and right limits and are also right continuous on $t$). We consider an infinitesimal generator $L$ and a stationary vector $p_0$. We denote by $P$ the associated probability on ($\Omega, {\cal B}$). All functions $f$ we consider bellow are in the set ${\cal L}^\infty (P)$. From the probability $P$ we define a Ruelle operator ${\cal L}^t, t\geq 0$, acting on functions $f:\Omega \to \mathbb{R}$ of ${\cal L}^\infty (P)$. Given $V:\Omega \to \mathbb{R}$, such that is constant in sets of the form $\{X_0=c\}$, we define a modified Ruelle operator $\tilde{{\cal L}}_V^t, t\geq 0$. We are able to show the existence of an eigenfunction $u$ and an eigen-probability $\nu_V$ on $\Omega$ associated to $\tilde{{\cal L}}^t_V, t\geq 0$. We also show the following property for the probability $\nu_V$: for any integrable $g\in {\cal L}^\infty (P)$ and any real and positive $t quation generalize, for the continuous time Markov Chain, a similar one for discrete time systems (and which is quite important for understanding the KMS states of certain $C^*$-algebras).
On the decoupling solution for pinch technique gluon propagator
2009-06-17
Within a simple Ansatz for gluon propagator and using perturbatively gauge invariant pinch-technique for Schwinger-Dyson equation, the upper limit on the effective gluon mass is derived. We calculated scheme invariant running coupling, which in order to be well defined, gives the upper limit on the gluon mass. The gluon mass cannot be larger then fraction of the QCD mass scale $\Lambda$, it is bounded by maximal the possible value $m/\Lambda\simeq 0.18$. For larger mass we get singular running coupling with Landau singularity situated bellow threshold $4m$, for $m$ between $0.18\Lambda $ and $0.34\Lambda$ it is located in the timelike regime, for larger $m$, $m>0.34\Lambda$ the singularity is gradually moving into the spacelike regime. Corresponding infrared value $\alpha(0)$ can be adjusted to settle chiral symmetry breaking when quarks are considered. For larger possible $m$, $m=0.18\Lambda$ the corresponding value is $\alpha(0)\simeq0.8$ and it is non-monotonous in the timelike low $q^2$. The model we use here is the same as considered in \cite{cornwall2009}, however we have arrived to a completely different conclusion, e.g we argue that there is no lower but upper limit on the gluon mass. The analyticity required by Kallen-Lehmann representation is not achieved for any value of $m$ since this is actually the inverse of the coupling and not the coupling itself which satisfies certain form of dispersion relation.
Power Games. "Blue Remembered Hills" by Dennis Potter. Brink Productions. [review]
2000-01-01
In this Brink Productions version, director John O’ Hare has shown that the play works every bit as well on stage as it does in the Forest of Dean . Co-designed by O’Hare and Justin Pennington the set has a stylised mound at centre stage which is given vegetation by sprays of greens and browns from lighting designer Mark Pennington. There is a pool at the edge of the stage where luckless victims get periodic dunkings, ropes hang like lianas waiting for Tarzan swoops, while at the back, at mezzanine level, is the hayloft where the eventual tragedy unfolds. As ever, Brink has gathered an able team. William Allert as Willie and Syd Brisbane as Peter have the daunting task of establishing much of the initial detail. When Audrey, portrayed with fierce energy by Lizzie Falkland, and Rebecca Havey’s seductively manipulative Angela, play mothers and fathers with Donald, they echo the abrasive language of their own parents- the men bellowing orders, the women argumentative and scolding. No sooner has one game dissolved into sulking and tears then another combination reconvenes. After Peter has been beaten by John, staunchly represented by David Mealor, he reasserts himself against Donald (an inventive Justin Ractliffe) using his hated nickname, Donald Duck. Potter shows the teasing to be as relentless as it is arbitrary and cruel.
Gravito-magnetic instabilities in anisotropically expanding fluids
2008-06-27
Gravitational instabilities in a magnetized Friedman - Robertson - Walker (FRW) Universe, in which the magnetic field was assumed to be too weak to destroy the isotropy of the model, are known and have been studied in the past. Accordingly, it became evident that the external magnetic field disfavors the perturbations' growth, suppressing the corresponding rate by an amount proportional to its strength. However, the spatial isotropy of the FRW Universe is not compatible with the presence of large-scale magnetic fields. Therefore, in this article we use the general-relativistic (GR) version of the (linearized) perturbed magnetohydrodynamic equations with and without resistivity, to discuss a generalized Jeans criterion and the potential formation of density condensations within a class of homogeneous and anisotropically expanding, self-gravitating, magnetized fluids in curved space-time. We find that, for a wide variety of anisotropic cosmological models, gravito-magnetic instabilities can lead to sub-horizonal, magnetized condensations. In the non-resistive case, the power spectrum of the unstable cosmological perturbations suggests that most of the power is concentrated on large scales (small k), very close to the horizon. On the other hand, in a resistive medium, the critical wave-numbers so obtained, exhibit a delicate dependence on resistivity, resulting in the reduction of the corresponding Jeans lengths to smaller scales (well bellow the horizon) than the non-resistive ones, while increasing the range of cosmological models which admit such an instability.
doi:10.1016/j.amepre.2007.09.012
State-of-the Science Statements produced by these Con-ferences are disseminated widely to healthcare practi-tioners, policymakers, patients, the media, and the general public. Since the program?s inception in 1977, NIH has held more than 130 such Conferences.
The views expressed in this article are those of the authors and do not reflect the official policy of the Department of the Army, Department of the Navy, the Department of Defense, or the United States...Full Text Available
Full Text Available.The views expressed in this article are those of the authors and do not reflect the official policy of the Department of the Army, Department of the Navy, the Department of Defense, or the United States Government.We are military service members (or employees of the US Government). This work was prepared as part of our official duties. Title 17 U.S.C. 105 provides that “Copyright protection under this title is not available for any work of the United States Government.” Title 17 U.S.C. 101 defines a US Government work as a work prepared by a military service member or employee of the US Government as part of that person's official duties.Warfare-related torso/abdominal wounds are often unique and complex and can pose a significant reconstructive challenge. The objective of this manuscript is to report the unique and successful management of a complex warfare-related abdominal wound. A dermal regenerate template in combination with negative pressure wound therapy was used to reconstitute lateral abdominal wall integrity after radical debridement and control of a necrotizing soft tissue infection of the torso. Adjunctive continuous negative pressure (vacuum assisted closure) therapy was used to provide external coverage and encourage the formation of granulation tissue. With this combination therapy, torso wound size decreased in surface area by 82% and the underlying musculofascial defect decreased by 64%. Neovascularization of a 55-cm2 acellular dermal graft was achieved as evidenced by surface granulation and complete survival of a partial-thickness skin graft. In our patient with a complex war injury, advanced tissue replacement techniques and negative pressure wound therapy resulted in a decreased abdominal wall defect, a restoration of abdominal wall integrity/domain, and allowed for concurrent surgical treatment of complex intra-abdominal injuries.
Uncinate Process Length in Birds Scales with Resting Metabolic Rate
Full Text Available.A fundamental function of the respiratory system is the supply of oxygen to meet metabolic demand. Morphological constraints on the supply of oxygen, such as the structure of the lung, have previously been studied in birds. Recent research has shown that uncinate processes (UP) are important respiratory structures in birds, facilitating inspiratory and expiratory movements of the ribs and sternum. Uncinate process length (UPL) is important for determining the mechanical advantage for these respiratory movements. Here we report on the relationship between UPL, body size, metabolic demand and locomotor specialisation in birds. UPL was found to scale isometrically with body mass. Process length is greatest in specialist diving birds, shortest in walking birds and intermediate length in all others relative to body size. Examination of the interaction between the length of the UP and metabolic demand indicated that, relative to body size, species with high metabolic rates have corresponding elongated UP. We propose that elongated UP confer an advantage on the supply of oxygen, perhaps by improving the mechanical advantage and reducing the energetic cost of movements of the ribs and sternum.
Uncinate Process Length in Birds Scales with Resting Metabolic Rate
A fundamental function of the respiratory system is the supply of oxygen to meet metabolic demand. Morphological constraints on the supply of oxygen, such as the structure of the lung, have previously...Full Text Available
The Role of Specific Tomato Volatiles in Tomato-Whitefly Interaction1[W][OA]
2009-10-01
Full Text Available.Bemisia tabaci (whitefly) infestations and the subsequent transfer of viruses are the cause of severe losses in crop production and horticultural practice. To improve biological control of B. tabaci, we investigated repellent properties of plant-produced semiochemicals. The mix of headspace volatiles, collected from naturally repellent wild tomato accessions, influenced B. tabaci initial choice behavior, indicating a role for plant semiochemicals in locating host plants. A collection of wild tomato accessions and introgression lines (Solanum pennellii LA716 × Solanum lycopersicum ‘Moneyberg’) were extensively screened for attractiveness to B. tabaci, and their headspace profiles were determined by means of gas chromatography-mass spectrometry. Correlation analysis revealed that several terpenoids were putatively involved in tomato-whitefly interactions. Several of these candidate compounds conferred repellence to otherwise attractive tomato plants when applied to the plant's branches on paper cards. The sesquiterpenes zingiberene and curcumene and the monoterpenes p-cymene, α-terpinene, and α-phellandrene had the strongest effects in free-choice bioassays. These terpenes also elicited a response of receptors on the insect's antennae as determined by electroantennography. Conversely, the monoterpene β-myrcene showed no activity in both assays. B. tabaci apparently uses, besides visual cues, specific plant volatile cues for the initial selection of a host. Altering whitefly choice behavior by manipulation of the terpenoid composition of the host headspace may therefore be feasible.
The Role of Specific Tomato Volatiles in Tomato-Whitefly Interaction1[W][OA]
2009-10-01
Bemisia tabaci (whitefly) infestations and the subsequent transfer of viruses are the cause of severe losses in crop production and horticultural practice. To improve biological control...Full Text Available
The Control of Environmental Tobacco Smoke: A Policy Review
2009-02-01
Full Text Available.According to World Health Organisation figures, 30% of all cancer deaths, 20% of all coronary heart diseases and strokes and 80% of all chronic obstructive pulmonary disease are caused by cigarette smoking. Environmental Tobacco Smoke (ETS) exposure has also been shown to be associated with disease and premature death in non-smokers. In response to this environmental health issue, several countries have brought about a smoking ban policy in public places and in the workplace. Countries such as the U.S., France, Italy, Ireland, Malta, the Netherlands, Sweden, Scotland, Spain, and England have all introduced policies aimed at reducing the population exposure to ETS. Several investigations have monitored the effectiveness of these smoking ban policies in terms of ETS concentrations, human health and smoking prevalence, while others have also investigated a number of alternatives to smoking ban policy measures. This paper reviews the state of the art in research, carried out in the field of ETS, smoking bans and Tobacco Control to date and highlights the need for future research in the area.
The Control of Environmental Tobacco Smoke: A Policy Review
2009-02-01
According to World Health Organisation figures, 30% of all cancer deaths, 20% of all coronary heart diseases and strokes and 80% of all chronic obstructive pulmonary disease are caused by cigarette...Full Text Available
Safety design features of the KLT-40S
2009-01-01
The KLT-40S is a modular reactor unit developed for a pilot floating nuclear cogeneration plant (PATES, in Russian), currently under construction in Severodvinsk, the Russian Federation. The KLT-40S nuclear installation belongs to a class of pressurized water reactors. The KLT-40S reactor unit is shown. Major specifications of the KLT-40S nuclear installation are given. A detailed design description of a floating NPP with KLT-40S reactor installations is provided. The main design features of the KLT-40S are the following: - Modular design of reactor unit: the reactor, the steam generators (SGs) and the main coolant pumps (MCPs) are connected with short nozzles, without using long pipelines. - Four-loop reactor cooling system with forced and natural convection of the coolant in the primary circuit. - Leaktight primary circuit with canned motor pumps and leaktight ... >>
Réalisation d'un caisson hermétique pour essais dynamiques
Un nouveau dispositif d'essais dynamiques sous vide ou sous atmosphère contrôlée a été réalisé. Cet ensemble est monté sur le bâti d'une machine hydropulse de 2 500 daN et de 100 mm de course. L'étanc ... Full Text Available
Digital Repository Infrastructure Vision for European Research (DRIVER)
Réalisation d'un caisson hermétique pour essais dynamiques
Un nouveau dispositif d'essais dynamiques sous vide ou sous atmosphère contrôlée a été réalisé. Cet ensemble est monté sur le bâti d'une machine hydropulse de 2 500 daN et de 100 mm de course. L'étanc ... Full Text Available
Digital Repository Infrastructure Vision for European Research (DRIVER)
Respiratory Self-Gating for Free-Breathing Abdominal Phase-Contrast Blood Flow Measurements
2009-04-01
PurposeTo demonstrate the feasibility of using a free-breathing (FB) respiratory self-gated (RSG) approach for abdominal phase-contrast (PC) blood flow measurements.Full Text Available
Respiratory Self-Gating for Free-Breathing Abdominal Phase-Contrast Blood Flow Measurements
2009-04-01
Full Text Available.PurposeTo demonstrate the feasibility of using a free-breathing (FB) respiratory self-gated (RSG) approach for abdominal phase-contrast (PC) blood flow measurements.Materials and MethodsPC-MRI flow measurements were performed within the right renal artery, common hepatic artery and main portal vein during breath-hold (BH) and FB with both signal averaging and RSG in eight healthy volunteers. Resultant images were qualitatively scored by two independent reviewers blinded to acquisition techniques. Blood flow volume and cross-sectional vessel size measurements were compared for three techniques.ResultsThe overall efficiency for the RSG-PC sequence was 38.9% ± 4.7%. Images acquired with RSG effectively mitigated respiratory motion artifacts which were clearly evident within FB signal averaged images. RSG produced similar image quality to that of BH techniques (p > 0.146) and resulted in similar vessel size measurements (p = 0.694). Flow results for both FB RSG and signal averaged reconstructions correlated well with BH flow measurements (r = 0.97 and 0.92, p < 0.001). However, only RSG methods demonstrated excellent absolute agreement with BH-PC flow measurements (p = 0.600) with signal averaged methods resulting in significant overestimations.ConclusionRSG methods can limit respiratory motion artifacts to reduce flow measurement inaccuracies during free-breathing PC measurements in the abdomen.
2009-06-01
Kihlstrom (2005) has recently called attention to the need for prospective longitudinal studies of dissociation. The present study assesses quality of...Full Text Available
2009-06-01
Full Text Available.Kihlstrom (2005) has recently called attention to the need for prospective longitudinal studies of dissociation. The present study assesses quality of early care and childhood trauma as predictors of dissociation in a sample of fifty-six low income young adults followed from infancy to age 19. Dissociation was assessed with the Dissociative Experiences Scale; quality of early care was assessed by observer ratings of mother-infant interaction at home and in the lab; and childhood trauma was indexed by state-documented maltreatment, self-report, and interviewer ratings of participants’ narratives. Regression analysis indicated that dissociation in young adulthood was significantly predicted by observed lack of parental responsiveness in infancy, while childhood verbal abuse was the only type of trauma that added to the prediction of dissociation. Implications are discussed in the context of previous prospective work also pointing to the important contribution of parental emotional unresponsiveness in the development of dissociation.
Partitioning clustering algorithms for protein sequence data sets
Full Text Available.BackgroundGenome-sequencing projects are currently producing an enormous amount of new sequences and cause the rapid increasing of protein sequence databases. The unsupervised classification of these data into functional groups or families, clustering, has become one of the principal research objectives in structural and functional genomics. Computer programs to automatically and accurately classify sequences into families become a necessity. A significant number of methods have addressed the clustering of protein sequences and most of them can be categorized in three major groups: hierarchical, graph-based and partitioning methods. Among the various sequence clustering methods in literature, hierarchical and graph-based approaches have been widely used. Although partitioning clustering techniques are extremely used in other fields, few applications have been found in the field of protein sequence clustering. It is not fully demonstrated if partitioning methods can be applied to protein sequence data and if these methods can be efficient compared to the published clustering methods.MethodsWe developed four partitioning clustering approaches using Smith-Waterman local-alignment algorithm to determine pair-wise similarities of sequences. Four different sets of protein sequences were used as evaluation data sets for the proposed methods.ResultsWe show that these methods outperform several other published clustering methods in terms of correctly predicting a classifier and especially in terms of the correctness of the provided prediction. The software is available to academic users from the authors upon request.
Partitioning clustering algorithms for protein sequence data sets
BackgroundGenome-sequencing projects are currently producing an enormous amount of new sequences and cause the rapid increasing of protein sequence databases. The unsupervised classification...Full Text Available
New study confirms process leading to disorder causing male characteristics in women
Ovarian stimulation of male steroids is the culprit behind polycystic ovary syndrome.
2009-03-01
Full Text Available.Advanced valvular lesions often contain ectopic mesenchymal tissues, which may be elaborated by an unidentified multipotent progenitor subpopulation within the valve interstitium. The identity, frequency, and differentiation potential of the putative progenitor subpopulation are unknown. The objectives of this study were to determine whether valve interstitial cells (VICs) contain a subpopulation of multipotent mesenchymal progenitor cells, to measure the frequencies of the mesenchymal progenitors and osteoprogenitors, and to characterize the osteoprogenitor subpopulation because of its potential role in calcific aortic valve disease. The multilineage potential of freshly isolated and subcultured porcine aortic VICs was tested in vitro. Progenitor frequencies and self-renewal capacity were determined by limiting dilution and colony-forming unit assays. VICs were inducible to osteogenic, adipogenic, chondrogenic, and myofibrogenic lineages. Osteogenic differentiation was also observed in situ in sclerotic porcine leaflets. Primary VICs had strikingly high frequencies of mesenchymal progenitors (48.0 ± 5.7%) and osteoprogenitors (44.1 ± 12.0%). High frequencies were maintained for up to six population doublings, but decreased after nine population doublings to 28.2 ± 9.9% and 5.8 ± 1.3%, for mesenchymal progenitors and osteoprogenitors, respectively. We further identified the putative osteoprogenitor subpopulation as morphologically distinct cells that occur at high frequency, self-renew, and elaborate bone matrix from single cells. These findings demonstrate that the aortic valve is rich in a mesenchyma l progenitor cell population that has strong potential to contribute to valve calcification.
2009-03-01
Advanced valvular lesions often contain ectopic mesenchymal tissues, which may be elaborated by an unidentified multipotent progenitor subpopulation within the valve interstitium. The identity, frequency,...Full Text Available
Four tourist destinations named best worldwide
Conservation International (CI) and National Geographic Traveler magazine announced today the winners of the 2004 World Legacy Award, given to environmental and social leaders in tourism. The award will be presented to ...
Explaining Adherence Success in Sub-Saharan Africa: An Ethnographic Study
2009-01-01
Full Text Available.BackgroundIndividuals living with HIV/AIDS in sub-Saharan Africa generally take more than 90% of prescribed doses of antiretroviral therapy (ART). This number exceeds the levels of adherence observed in North America and dispels early scale-up concerns that adherence would be inadequate in settings of extreme poverty. This paper offers an explanation and theoretical model of ART adherence success based on the results of an ethnographic study in three sub-Saharan African countries.Methods and FindingsDeterminants of ART adherence for HIV-infected persons in sub-Saharan Africa were examined with ethnographic research methods. 414 in-person interviews were carried out with 252 persons taking ART, their treatment partners, and health care professionals at HIV treatment sites in Jos, Nigeria; Dar es Salaam, Tanzania; and Mbarara, Uganda. 136 field observations of clinic activities were also conducted. Data were examined using category construction and interpretive approaches to analysis. Findings indicate that individuals taking ART routinely overcome economic obstacles to ART adherence through a number of deliberate strategies aimed at prioritizing adherence: borrowing and “begging” transport funds, making “impossible choices” to allocate resources in favor of treatment, and “doing without.” Prioritization of adherence is accomplished through resources and help made available by treatment partners, other family members and friends, and health care providers. Helpers expect adherence and make their expectations known, creating a responsibility on the part of patients to adhere. Patients adhere to promote good will on the part of helpers, thereby ensuring help will be available when future needs arise.ConclusionAdherence success in sub-Saharan Africa can be explained as a means of fulfilling social responsibilities and thus preserving social capital in essential relationships.
Explaining Adherence Success in Sub-Saharan Africa: An Ethnographic Study
2009-01-01
BackgroundIndividuals living with HIV/AIDS in sub-Saharan Africa generally take more than 90% of prescribed doses of antiretroviral therapy (ART). This number exceeds...Full Text Available
Exigências Térmicas de Bemisia tabaci (Genn.) Biótipo B (Hemiptera: Aleyrodidae)
2002-07-01
Full Text Available
2009-09-01
Substance use outcomes were examined for 351 youth participating in a randomized controlled trial designed to assess the efficacy of a school-based multimodal universal preventive intervention,...Full Text Available
2009-09-01
Full Text Available.Substance use outcomes were examined for 351 youth participating in a randomized controlled trial designed to assess the efficacy of a school-based multimodal universal preventive intervention, Linking the Interests of Families and Teachers (LIFT). Frequency of any use of tobacco, alcohol, and other drugs was assessed via self-report from grades 5 through 12. Latent variable growth models specified average levels, linear, and accelerated growth. The LIFT intervention had a significant effect on reducing the rate of growth in use of tobacco and illicit drugs, particularly for girls, and had an overall impact on average levels of use of tobacco, alcohol, and illicit drugs. Average tobacco use reductions were mediated by increases in family problem solving. The intervention obtained significant indirect effects on growth in substance use through intervention effects on reduced playground aggression and increased family problem solving. The intervention was also associated with roughly a 10% reduced risk in initiating tobacco and alcohol use. Implications for future studies of multimodal preventive interventions are discussed.
Full Text Available.BackgroundEpidemiological research into the role of traffic pollution on chronic respiratory and allergic disease has focused primarily on children. Studies in adults, in particular those based on objective outcomes such as bronchial hyperresponsiveness, skin sensitisation, and lung function, are limited.MethodsWe have used an existing cohort of 2644 adults aged 18–70 living in Nottingham, UK, for whom baseline health and demographic data were collected in 1991 and computed two markers of exposure to traffic: distance between the home and nearest main road and modelled outdoor nitrogen dioxide (NO2) concentration at the home location. Using multiple regression techniques, we analysed cross-sectional associations with bronchial hyperresponsiveness, FEV1, spirometry-defined COPD, skin test positivity, total IgE and questionnaire-reported wheeze, asthma, eczema and hayfever in 2599 subjects, and longitudinal associations with decline in FEV1 in 1329 subjects followed-up nine years later in 2000.ResultsThere were no significant cross-sectional associations between home proximity to the roadside or NO2 level on any of the outcomes studied (adjusted OR of bronchial hyperresponsiveness in relation to living ≤150 m vs >150 m from a road = 0.92, 95% CI 0.68 to 1.24). Furthermore, neither exposure was associated with a significantly greater decline in FEV1 over time (adjusted mean difference in ΔFEV1 for living ≤150 m vs >150 m of a road = 10.03 ml, 95% CI, -33.98 to 54.04).ConclusionThis study found no evidence to suggest that living in close proximity to traffic is a major determinant of asthma, allergic disease or COPD in adults.
BackgroundEpidemiological research into the role of traffic pollution on chronic respiratory and allergic disease has focused primarily on children. Studies in adults, in particular...Full Text Available
Distribuição vertical e setorial das ninfas de mosca-branca nas folhas do meloeiro
2003-01-01
Full Text Available
2009-05-15
SummaryChromosome segregation and the repair of DNA double-strand breaks (DSBs) require cohesin, the protein complex that mediates sister chromatid cohesion. Cohesion requires...Full Text Available
2009-05-15
Full Text Available.SummaryChromosome segregation and the repair of DNA double-strand breaks (DSBs) require cohesin, the protein complex that mediates sister chromatid cohesion. Cohesion requires both a chromatin binding step and a subsequent tethering step called cohesion generation. Here we provide insight into how cohesion generation is restricted to S phase but can be activated in G2/M by a DSB in budding yeast. We show that Wpl1p inhibits cohesion in G2/M. A DSB counteracts Wpl1p and stimulates cohesion generation by first inducing the phosphorylation of the Mcd1p subunit of cohesin. This phosphorylation activates Eco1p-dependent acetylation of Mcd1p, which in turn antagonizes Wpl1p. Previous studies show that Eco1p antagonizes Wpl1p in S phase by acetylating the Smc3p subunit of cohesin. We show that Mcd1p and Smc3p acetylation antagonize Wpl1p only in their proper context. Thus, Eco1p antagonizes Wpl1p in distinct ways to modulate cohesion generation during the cell cycle and after DNA damage.
Development of semi-remote handling system of vacuum flange
2006-01-01
The residual radiation level of the J-PARC 50 GeV synchrotron will be rather high at the injection, extraction, and collimator sections. To reduce the radiation dose of workers, a 'semi-remote' handling system of vacuum flange is being developed for devices in the high radiation sections. It enables us to couple/decouple vacuum flanges 'semi-remotely'. The present status of development is described in this paper. (author)
Desensitization to dyspnea in COPD with specificity for exercise training mode
2009-01-01
Patients with chronic obstructive pulmonary disease (COPD) exhibit improved exercise capacity after physical training due to reconditioning and improved ventilatory efficiency. Other possible effects...Full Text Available
Desensitization to dyspnea in COPD with specificity for exercise training mode
2009-01-01
Full Text Available.Patients with chronic obstructive pulmonary disease (COPD) exhibit improved exercise capacity after physical training due to reconditioning and improved ventilatory efficiency. Other possible effects are improved ventilatory muscle function and desensitization to dyspnea. We compared general physical training (GPT), consisting of walking and stair climbing exercises, with inspiratory muscle training (IMT), consisting of targeted breathing through inspiratory resistances, in two groups with severe COPD. Seven subjects; age 60 (8) years, forced expiratory volume in one second (FEV1) 0.84 (0.35) L, arterial oxygen tension (PaO2) 11.1 (0.8) kPa, arterial carbon dioxide tension (PaCO2) 4.9 (0.3) kPa, had GPT and nine subjects; age 60 (9) years, FEV1 0.83 (0.31) L, PaO2 10.4 (0.8) kPa, PaCO2 4.4 (0.5) kPa had IMT. Each group trained daily for 30 minutes for eight weeks and 70% of the sessions were supervised. Six minute walking distance increased in both groups: 32 m (6.9% P < 0.05) with GPT and 23 m (4.8%; P < 0.05) with IMT but significant improvements in symptom-limited incremental cycle exercise performance were not detected. Breathlessness by visual analog scale was reduced following 6-minute walks after GPT (P < 0.05) but not after IMT. Following maximal incremental tests, breathlessness scores were unchanged for both groups. COPD patients performing regular physical exercise report reductions in breathlessness which are specific to the exercise training mode.
Bundling 2 low-cost heart drugs prevents heart attack and stroke in large, diverse ..
A new Kaiser Permanente study found that bundling two generic, low-cost drugs -- a cholesterol-lowering statin and a blood pressure-lowering drug -- and giving daily doses to 68,560 people with diabetes or heart disease ...
In Nature plants are constantly challenged by a variety of environmental stresses that could lead to disruptions in cellular homeostasis. Programmed cell death (PCD) is a fundamental cellular process...Full Text Available
Full Text Available.In Nature plants are constantly challenged by a variety of environmental stresses that could lead to disruptions in cellular homeostasis. Programmed cell death (PCD) is a fundamental cellular process that is often associated with defense responses to pathogens, during development and in response to abiotic stresses in fungi, animals and plants. Although there are many characteristics shared between different types of PCD events, it remains unknown whether a common mechanism drives various types of PCD in eukaryotes. One candidate regulator for such a mechanism is Bax Inhibitor-1 (BI-1), an evolutionary conserved, endoplasmic reticulum (ER)-resident protein that represents an ancient cell death regulator that potentially regulates PCD in all eukaryotes. Recent findings strongly suggested that BI-1 plays an important role in the conserved ER stress response pathway to modulate cell death induction in response to multiple types of cell death signals. As ER stress signaling pathways has been suggested to play important roles not only in the control of ER homeostasis but also in other biological processes such as the response to pathogens and abiotic stress in plants, BI-1 might function to control the convergence point that modulates the level of the “pro-survival and pro-death” signals under multiple stress conditions.
Assembling the Marine Metagenome, One Cell at a Time
The difficulty associated with the cultivation of most microorganisms and the complexity of natural microbial assemblages, such as marine plankton or human microbiome, hinder genome reconstruction of...Full Text Available
Assembling the Marine Metagenome, One Cell at a Time
Full Text Available.The difficulty associated with the cultivation of most microorganisms and the complexity of natural microbial assemblages, such as marine plankton or human microbiome, hinder genome reconstruction of representative taxa using cultivation or metagenomic approaches. Here we used an alternative, single cell sequencing approach to obtain high-quality genome assemblies of two uncultured, numerically significant marine microorganisms. We employed fluorescence-activated cell sorting and multiple displacement amplification to obtain hundreds of micrograms of genomic DNA from individual, uncultured cells of two marine flavobacteria from the Gulf of Maine that were phylogenetically distant from existing cultured strains. Shotgun sequencing and genome finishing yielded 1.9 Mbp in 17 contigs and 1.5 Mbp in 21 contigs for the two flavobacteria, with estimated genome recoveries of about 91% and 78%, respectively. Only 0.24% of the assembling sequences were contaminants and were removed from further analysis using rigorous quality control. In contrast to all cultured strains of marine flavobacteria, the two single cell genomes were excellent Global Ocean Sampling (GOS) metagenome fragment recruiters, demonstrating their numerical significance in the ocean. The geographic distribution of GOS recruits along the Northwest Atlantic coast coincided with ocean surface currents. Metabolic reconstruction indicated diverse potential energy sources, including biopolymer degradation, proteorhodopsin photometabolism, and hydrogen oxidation. Compared to cultured relatives, the two uncultured flavobacteria have small genome sizes, few non-coding nucleotides, and few paralogous genes, suggesting adaptations to narrow ecological niches. These features may have contributed to the abundance of the two taxa in specific regions of the ocean, and may have hindered their cultivation. We demonstrate the power of single cell DNA sequencing to generate reference genomes of uncultured taxa from a complex microbial community of marine bacterioplankton. A combination of single cell genomics and metagenomics enabled us to analyze the genome content, metabolic adaptations, and biogeography of these taxa.
Analysis of small bubbles in glass by glow discharge-Time-of-flight mass spectrometry
2009-01-01
The chemical reactions occurring during the glass manufacturing processes can give rise to small bubbles, damaging the required glass properties. To avoid eventual bubbles formation, the chemical composition of the bubbles should be known to trace back the gas sources and take appropriate corrective actions. Mass spectrometry is a most adequate detection technique for such purpose due to its ability to provide the required information in a short time. Analysis of these small bubbles in glass requires a system incorporating a very small volume (for a fast evacuation of the entire line and low dilution of the analytes) and a fast mass analyser allowing the quasi-simultaneous detection of the whole spectral interval of interest, such as a time-of-flight mass spectrometer (TOFMS). In this work...
Acoustic communication in crocodilians: from behaviour to brain
2009-01-01
ABSTRACT Crocodilians and birds are the modern representatives of Phylum Archosauria. Although there have been recent advances in our understanding of the phylogeny and ecology of ancient archosaurs like dinosaurs, it still remains a challenge to obtain reliable information about their behaviour. The comparative study of birds and crocodiles represents one approach to this interesting problem. One of their shared behavioural features is the use of acoustic communication, especially in the context of parental care. Although considerable data are available for birds, information concerning crocodilians is limited. The aim of this review is to summarize current knowledge about acoustic communication in crocodilians, from sound production to hearing processes, and to stimulate research in this...
Acetaldehyde and hexanaldehyde from cultured white cells
Full Text Available.BackgroundNoninvasive detection of innate immune function such as the accumulation of neutrophils remains a challenge in many areas of clinical medicine. We hypothesized that granulocytes could generate volatile organic compounds.MethodsTo begin to test this, we developed a bioreactor and analytical GC-MS system to accurately identify and quantify gases in trace concentrations (parts per billion) emitted solely from cell/media culture. A human promyelocytic leukemia cell line, HL60, frequently used to assess neutrophil function, was grown in serum-free medium.ResultsHL60 cells released acetaldehyde and hexanaldehyde in a time-dependent manner. The mean ± SD concentration of acetaldehyde in the headspace above the cultured cells following 4-, 24- and 48-h incubation was 157 ± 13 ppbv, 490 ± 99 ppbv, 698 ± 87 ppbv. For hexanaldehyde these values were 1 ± 0.3 ppbv, 8 ± 2 ppbv, and 11 ± 2 ppbv. In addition, our experimental system permitted us to identify confounding trace gas contaminants such as styrene.ConclusionThis study demonstrates that human immune cells known to mimic the function of innate immune cells, like neutrophils, produce volatile gases that can be measured in vitro in trace amounts.
Acetaldehyde and hexanaldehyde from cultured white cells
BackgroundNoninvasive detection of innate immune function such as the accumulation of neutrophils remains a challenge in many areas of clinical medicine. We hypothesized that granulocytes...Full Text Available
2009-05-06
Full Text Available.Activity-dependent plasticity occurs throughout the CNS. However, investigations of skill acquisition usually focus on cortex. To expand the focus, we analyzed in humans the development of operantly conditioned H-reflex change, a simple motor skill that develops gradually and involves plasticity in both the brain and the spinal cord. Each person completed 6 baseline and 24 conditioning sessions over 10 weeks. In each conditioning session, the soleus H-reflex was measured while the subject was or was not asked to increase (HRup subjects) or decrease (HRdown subjects) it. When the subject was asked to change H-reflex size, immediate visual feedback indicated whether a size criterion had been satisfied. Over the 24 conditioning sessions, H-reflex size gradually increased in 6 of 8 HRup subjects and decreased in 8 of 9 HRdown subjects, resulting in final sizes of 140(±12)% and 69(±6)% of baseline size, respectively. The final H-reflex change was the sum of within-session (i.e., task-dependent) adaptation and across-session (i.e., long-term) change. Task-dependent adaptation appeared within 4–6 sessions and persisted thereafter, averaging +13% in HRup subjects and −15% in HRdown subjects. In contrast, long-term change began after 10 sessions and increased gradually thereafter, reaching +27% in HRup subjects and −16% in HRdown subjects. Thus, the acquisition of H-reflex conditioning consists of two phenomena – task-dependent adaptation and long-term change – that together constitute the new motor skill. In combination with previous data, this new finding further elucidates the interaction of plasticity in brain and spinal cord that underlies the acquisition and maintenance of motor skills.
2009-05-06
Activity-dependent plasticity occurs throughout the CNS. However, investigations of skill acquisition usually focus on cortex. To expand the focus, we analyzed in humans the development of operantly...Full Text Available
A retrospective analysis of health systems in Denmark and Kaiser Permanente
2008-01-01
ABSTRACT: BACKGROUND: To inform Danish health care reform efforts, we compared health care system inputs and performance and assessed the usefulness of these comparisons for informing policy. METHODS: Retrospective analysis of secondary data in the Danish Health Care System (DHS) with 5.3 million citizens and the Kaiser Permanente integrated delivery system (KP) with 6.1 million members in California. We used secondary data to compare population characteristics, professional staff, delivery structure, utilisation and quality measures, and direct costs. We adjusted the cost data to increase comparability. RESULTS: A higher percentage of KP patients had chronic conditions than did patients in the DHS: 6.3% vs. 2.8% (diabetes) and 19% vs. 8.5% (hypertension), respectively. KP had fewer total physicians and staff compared to DHS, with134 physicians/100,000 individuals versus 311 physicians/100,000 individuals. KP physicians are salaried employees; in contrast, DHS primary care physicians own and run their practices, remunerated by a mixture of capitation and fee-for-service payments, while most specialists are employed at largely public hospitals. Hospitalisation rates and lengths of stay (LOS) were lower in KP, with mean acute admission LOS of 3.9 days versus 6.0 days in the DHS, and, for stroke admissions, 4.2 days versus 23 days. Screening rates also differed: 93% of KP members with diabetes received retinal screening; only 46% of patients in the DHS with diabetes did. Per capita operating expenditures were PPP$1,951 (KP) and PPP $1,845 (DHS). CONCLUSION: Compared to the DHS, KP had a population with more documented disease and higher operating costs, while employing fewer physicians and resources like hospital beds. Observed quality measures also appear higher in KP. However, simple comparisons between health care systems may have limited value without detailed information on mechanisms underlying differences or identifying translatable care improvement strategies. We suggest items for more in-depth analyses that could improve the interpretability of findings and help identify lessons that can be transferred.
A pneumatic power harvesting ankle-foot orthosis to prevent foot-drop
BackgroundA self-contained, self-controlled, pneumatic power harvesting ankle-foot orthosis (PhAFO) to manage foot-drop was developed and tested. Foot-drop is due to a disruption...Full Text Available
A decade of user operation on the macromolecular crystallography MAD beamline ID14-4 at the ESRF
2009-11-01
ID14-4 at the ESRF is the first tunable undulator-based macromolecular crystallography beamline that can celebrate a decade of user service. During this time ID14-4 has not only been instrumental in...Full Text Available
A decade of user operation on the macromolecular crystallography MAD beamline ID14-4 at the ESRF
2009-11-01
Full Text Available.ID14-4 at the ESRF is the first tunable undulator-based macromolecular crystallography beamline that can celebrate a decade of user service. During this time ID14-4 has not only been instrumental in the determination of the structures of biologically important molecules but has also contributed significantly to the development of various instruments, novel data collection schemes and pioneering radiation damage studies on biological samples. Here, the evolution of ID14-4 over the last decade is presented, and some of the major improvements that were carried out in order to maintain its status as one of the most productive macromolecular crystallography beamlines are highlighted. The experimental hutch has been upgraded to accommodate a high-precision diffractometer, a sample changer and a large CCD detector. More recently, the optical hutch has been refurbished in order to improve the X-ray beam quality on ID14-4 and to incorporate the most modern and robust optical elements used at other ESRF beamlines. These new optical elements will be described and their effect on beam stability discussed. These studies may be useful in the design, construction and maintenance of future X-ray beamlines for macromolecular crystallography and indeed other applications, such as those planned for the ESRF upgrade.
Website Policies and Important Links Comments
 |
 |
 |
WorldWideScience.org is maintained by the
U.S. Department of Energy's
Office of Scientific and Technical Information as the Operating Agent
for the WorldWideScience Alliance.