Science.gov (United States)

This article examines relevant government policy documents on education and culture and discovers that Nigerian education authorities do not "discriminate" against art and culture in its articulation of educational policies per se, but lack of administrative machinery or political will has resulted in the deprivation of the Nigerian child in the process of creative activity in early childhood development. The article argues that lack of creative ability in our educational products is perhaps a major setback in the nation's quest for industrial and technological development. In this article a new art curriculum for elementary schools is advocated as a means of engaging the young child in order to attain functional educational skills necessary in the world of work.

Science.gov (United States)

... Accession Number : ADA111683. Title : Coherency Effects on Retinal Neural Processes (ERG) of Pseudemys. Descriptive ...

CERN Document Server

Results that contradict known physics, data manipulated, lack of vigilance by co-authors, failures in the system for scientific publication... Last September a US Committee of Enquiry unveiled one of the most serious frauds in the history of physics. Over a two year period, a young researcher at Bell Laboratories had published a large number of articles with exciting results for solid state physics, but which, alas, were fraudulent! Obviously a fraud of this magnitude is exceptional. However, it did serve to focus attention on the problem of integrity and honesty in research practices. This subject, crucial to the well-being and credibility of scientific research, will be the central theme of the lecture given by Nicholas Steneck, Professor of History at the University of Michigan. A leading expert on this issue, on which he has published extensively, he is a consultant to the Office of Research Integrity in the US, and has been closely involved in public ...

British Library Electronic Table of Contents (United Kingdom)

Research and bioethical policies are increasingly seen to facilitate, rather than to impede, scientific progress. Bioethical structures, nonetheless, often fail to account for or to shape the specific social surrounds in which scientific research is conducted. In Taiwan, a perceived shortage in human biological donations threatens to hamper stem cell research progress. This paper considers the stalled national biobank project and the lack of a reliable embryo supply for stem cell research, and suggests that one must look beyond regulatory structures in seeking explanations for such shortages. Specific aspects of Taiwan's democratization and social changes combine with problematic relations between patients and physicians to shape the terrain upon which human biologicals are given or withhe...

Energy Technology Data Exchange (ETDEWEB)

Indicators are important tools for communicating and making accessible scientific and technical information to policymakers and the general public. They therefore play an important role in transforming information into action. Worldwide, many initiatives are underway to construct indicators for a variety of purposes, including those for reporting on sustainable development. This paper briefly describes the attempts made so far, but stresses that the users of the indicators should play a greater role in indicator construction. In developing countries, a substantial lack of data has meant that specific policy formulation may develop without adequate technical input. In developed countries also, data gaps may hinder policy formulation, implementation, and evaluation. However, the development of indicators as tools to assist in the management of hazardous wastes and toxic chemicals is still in the early stages of formulation. A ...

Energy Technology Data Exchange (ETDEWEB)

Three popular imaging methods were used to carry out seismic migration from the Alberta foothills: Kirchhoff integral, reverse-time and explicit finite-difference migration methods. The imaging comparisons of reverse-time, Kirchhoff and f-x post-stack depth migration leads to the following conclusions. All of the three migration methods can provide acceptable and well-imaged intermediate results on the simplest model. Post-stack migration was not very sensitive to the accuracy of the velocity field once a reliable structural stack was available. With respect to the imaging accuracy and calculation cost, the Kirchhoff migration method seemed to be superior to reverse-time and f-x migration algorithms because its results on different kinds of velocity cases were basically kept coherent and consistent with the velocity model given by Mobil. Because of the lack of an accurate velocity field, reverse-time migration was less stable than the other two ...

Energy Technology Data Exchange (ETDEWEB)

After a four-year operation, positive results have been achieved. A community of action has been built that enhances RD and D of fuel cells in the French context. PACo is a light and flexible form of organization that supports the strategy of its members through a shared coherent vision. A right balance between cooperation and competition has been found and cross-sector and public-private synergies have been effectively exploited in its midst. This type of partnership demonstrates that it is on the way of creating value in a cost effective manner combining private and public funds. It should be underlined however that the remaining road to go is long before fuel cells become popular and commercially widespread. The time management will be critical in order to keep the momentum and find a pathway to this goal sustainable in the long run. In this process of radical innovation, PACo as any learning organization is committed to continuously look for further ...

UK PubMed Central (United Kingdom)

Purpose. To describe the characteristics of idiopathic macular holes (MH) on optical coherence tomography (OCT) and correlate OCT with clinical assessment. Design....Full Text Available

Science.gov (United States)

The HIPAA privacy rule (HIPAA) has had both positive and negative effects on the release of patient information by healthcare facilities. Although the intention of HIPAA was to protect patient privacy and to promote security and confidentiality of patient information, it has had unintended consequences for facilities. To identify some of these unintended effects, two expert panels of health information management directors from healthcare facilities participated in the nominal group technique meetings. They identified 70 barriers related to release of patient information associated with the implementation of HIPAA. The perceived biggest barriers were increases in the public's misunderstanding about release of patient information, lack of an umbrella policy or regulation defining infractions and enforcement that allows individual institutions to make their own interpretations, and challenges to health information management professionals in ...

Energy Technology Data Exchange (ETDEWEB)

Recently it was demonstrated that long-lived quantum coherence exists during excitation energy transport in photosynthesis. It is a valid question up to which length, time and mass scales quantum coherence may extend, how one may detect this coherence and what, if any, role it plays in the dynamics of the system. Here we suggest that the selectivity filter of ion channels may exhibit quantum coherence, which might be relevant for the process of ion selectivity and conduction. We show that quantum resonances could provide an alternative approach to ultrafast two-dimensional (2D) spectroscopy to probe these quantum coherences. We demonstrate that the emergence of resonances in the conduction of ion channels that are modulated periodically by time-dependent external electric fields can serve as signatures of quantum coherence in such a system. Assessments of ...

Science.gov (United States)

... MTR 93B0000095 Proposed Network Security Policy for Integrated Tactical Warning ... Proposed Network security Policy for Integrated Tactical ...

Wastenet

Labeling of organic res- taurants, cantinas, etc.

Science.gov (United States)

Basic cross site scripting attacks

Energy Technology Data Exchange (ETDEWEB)

Supracrustal rocks, although volumetrically minor, are found throughout the Archean basement of the central and northern Wind River Mountains. Detailed mapping in the Medina Mountain area suggests that at least two discrete sedimentation events are preserved. The older sequence occurs as melanosomes in a multiple deformed migmatitic gneiss. Rock types include mafic rocks (metavolcanics.), calc-silicates, iron formation and rare pelites. Although retrogression is widespread, small patches with granulite mineralogies are found preserved. The younger supracrustal sequence consists of banded amphibolites, calc-silicates, semipelitic and pelitic gneiss. These rocks form synformal structures that are up to 4 km in length. The coherent nature of these rocks and the lack of the aforementioned porphyritic dikes strongly suggests that this sequence, the Medina Mountain. Supracrustals (MMS) is considerably younger than the supracrustal rocks found in the ...

UK PubMed Central (United Kingdom)

PurposeTo describe ocular findings for a 34-year-old man with chronic solar retinopathy using high-speed ultrahigh-resolution (UHR) optical coherence tomography (OCT).Full Text Available

UK PubMed Central (United Kingdom)

Purpose.To investigate the characteristics of a spectral-domain optical coherence tomography (SD-OCT) image phenomenon known as the mirror artifact, calculate its prevalence, analyze...Full Text Available

UK PubMed Central (United Kingdom)

We present a method to make phantoms of coronary arteries for intravascular optical coherence tomography (IV-OCT). The phantoms provide a calibrated OCT response similar to the layered structure of...Full Text Available

International Nuclear Information System (INIS)

We present a simple protocol to purify a coherent-state superposition that has undergone a linear lossy channel. The scheme constitutes only a single beam splitter and a homodyne detector, and thus is experimentally feasible. In practice, a superposition of coherent states is transformed into a classical mixture of coherent states by linear loss, which is usually the dominant decoherence mechanism in optical systems. We also address the possibility of producing a larger amplitude superposition state from decohered states, and show that in most cases the decoherence of the states are amplified along with the amplitude.

Science.gov (United States)

... and flashtube. Unfortunately, we had insufficient laser intensity to use the harmonic from a KDP crystal as a monitor. This ...

CERN Document Server

We report an observation of a delayed all-optical routing/switching phenomenon based on ultraslow group velocity of light via nondegenerate four-wave mixing processes in a defected solid medium. Unlike previous demonstrations of enhanced four-wave mixing processes using the slow light effects, the present observation demonstrates a direct retrieval of the resonant Raman-pulse excited spin coherence into photon coherence through coherence conversion processes.

CERN Document Server

The Nystrom method is an efficient technique to speed up large-scale learning applications by generating low-rank approximations. Crucial to the performance of this technique is the assumption that a matrix can be well approximated by working exclusively with a subset of its columns. In this work we relate this assumption to the concept of matrix coherence and connect matrix coherence to the performance of the Nystrom method. Making use of related work in the compressed sensing and the matrix completion literature, we derive novel coherence-based bounds for the Nystrom method in the low-rank setting. We then present empirical results that corroborate these theoretical bounds. Finally, we present more general empirical results for the full-rank setting that convincingly demonstrate the ability of matrix coherence to measure the degree to which information can be extracted from a subset of columns.

International Nuclear Information System (INIS)

When energetic bunches of electrons traverse an undulator field, they can spontaneously emit radiation both coherently and incoherently. Although it has generally been assumed that undulator radiation is incoherent at wavelengths short compared to the longitudinal size of the electron bunch, several recent observations have proved this assumption false. Furthermore, the appearance of coherent radiation is often accompanied by a significant increase in radiated power. Here we report observations of strongly enhanced coherent spontaneous radiation together with direct measurements, using transition radiation techniques, of the electron distributions responsible for the coherent emission. We also report demonstrated enhancements in the predicted spontaneous radiated power by as much as 6x10"4 using electron bunch compression. copyright 1996 American Institute of Physics.

Science.gov (United States)

...2010-10-01 false Preferences under the Energy Policy Act. 926.7005 Section...Acquisition Regulations System DEPARTMENT OF ENERGY SOCIOECONOMIC PROGRAMS OTHER SOCIOECONOMIC...Implementation of Section 3021 of the Energy Policy Act of 1992 926.7005...

Science.gov (United States)

ICU telemedicine uses audiovisual conferencing technology to provide critical care from a remote location. Research is needed to best define the optimal use of ICU telemedicine, but efforts are hindered by methodological challenges and the lack of an organized delivery approach. We convened an interdisciplinary working group to develop a research agenda in ICU telemedicine, addressing both methodological and knowledge gaps in the field. To best inform clinical decision-making and health policy, future research should be organized around a conceptual framework that enables consistent descriptions of both the study setting and the telemedicine intervention. The framework should include standardized methods for assessing the preimplementation ICU environment and describing the telemedicine program. This framework will facilitate comparisons across studies and improve generalizability by permitting context-specific interpretation. Research based on ...

Energy Technology Data Exchange (ETDEWEB)

The Clean Air Act establishes New Source Review (NSR) programs that apply to the construction or modification of major stationary emissions sources. In 2002 and 2003, the U.S. Environmental Protection Agency revised its rules to narrow the applicability of NSR to facility renovations. Congress then mandated a National Research Council study of the effects of the rules. An electricity-sector model - the Integrated Planning Model (IPM) - was used to explore the possible effects of the equipment replacement provision (ERP), the principal NSR change that was to affect the power-generation industry. The studies focused in particular on coal-fired electricity generating units, EGUs, for two reasons. First, coal-fired EGUs are important contributors of these pollutants, accounting for approximately 70 and 20% of nations SO{sub 2} and NOx emissions in 2004, respectively. Second, the shares of total capacity of large coal-fired EGUs that lack flue-gas desulfurization to ...

Science.gov (United States)

Resources & Guides Schools Airmen Testing FAA Academy Federal Aviation Administration Web Policies & Notices Print Email | Updated: 4:46 pm ET March 2, 2011 Employment...

Science.gov (United States)

... development of SC policy within DOD, because it describes the necessary link between DOD ... strategy convolutes USG efforts to develop SC policy. ...

CERN Document Server

Composition of the Scientific Policy Committee Appointment of Two New Members by the Chairman of the Committee (J. Specht, A. Wroblewski)

Energy Technology Data Exchange (ETDEWEB)

We investigated the Raman coherence characteristics of a solid hydrogen film deposited on a sapphire substrate held at 5.3 K. Using Raman coherence prepared with two single-frequency pulsed lasers, we generated the multiorder coherent Raman sidebands in solid hydrogen film. The highorder Raman sidebands were obtained under strong pumping intensities (>= 230 MW/cm{sup 2}). The generated anti-Stokes(AS)-Raman sidebands extend from the ultraviolet (292 nm for the AS5 band) to the visible (565 nm for the AS1 band) region. The multiorder Raman sideband generation is found to be due to the parametric coupling of pump and coupling lasers. The frequency conversion efficiency from pumping beams to the first AS-Raman sideband shows a maximum (14 %) at a pumping intensity of 360 MW/cm{sup 2}. From an experiment that makes the multimode probe beam beat with the prepared Raman coherence, we found that the ...

UK PubMed Central (United Kingdom)

BackgroundPoverty, lack of female empowerment, and lack of education are major risk factors for childhood illness worldwide. Microcredit programs, by offering small loans to poor...Full Text Available

International Nuclear Information System (INIS)

We present a protocol for quantum key distribution using discrete modulation of coherent states of light. Information is encoded in the variable phase of coherent states which can be chosen from a regular discrete set ranging from binary to continuous modulation similar to phase-shift keying in classical communication. Information is decoded by simultaneous homodyne measurement of both quadratures and requires no active choice of basis. The protocol utilizes either direct or reverse reconciliation both with and without postselection. We analyze the security of the protocol and show how to enhance it by the optimal choice of all variable parameters of the quantum signal.

Energy Technology Data Exchange (ETDEWEB)

The Linac Coherent Light Source (LCLS) will be the world's first x-ray free-electron laser (FEL). To ensure the vitality of FEL lasing, a longitudinal feedback system is required together with other diagnostics. In this paper, we study the possibility of using Coherent Synchrotron Radiation (CSR) from the chicane as a diagnostic tool for bunch length feedback. Studies show that CSR is a good candidate, even for a non-Gaussian, double-horn longitudinal charge distribution as in the LCLS. We further check the possibility for detecting possible microbunching.

Science.gov (United States)

... civilian leadership. The leadership of the Marine Corps believes this represents somewhat of a benchmark for SC policy. It ...

Wastenet

Sc.Technology & Policy (M.I.T., USA) M.Sc.

Wastenet

...this page document analysis carried out during the policy development of the CRC Energy Efficiency Scheme. policy, background, carbon, reduction,...commitment, energy efficiency, CRC, Policy background Spending Review Announcement In the October 2010 Spending Review, the UK Government announced that the CRC ... Revenue from the sale of CRC allowances, totalling ٟ billion a year by 2014/15, will be used to support ... The implications of this announcement for CRC are: In order to clarify the price signal to participants and to support the public ...

KoreaScience (Korea)

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Science.gov (United States)

For coupled quantum wires and dots, tunneling effects and coherent transport for quantum computing are being studied. In 2D systems, electron-hole bilayers for exciton...

UK PubMed Central (United Kingdom)

Absolute measurements of cerebral blood flow (CBF) are an important endpoint in studies of cerebral pathophysiology. Currently no accepted method exists for in vivo longitudinal...Full Text Available

Science.gov (United States)

... of Dist SpeA tI/ __LLL5' Page 5. 3 the coherent effects on the spontaneous radiation, we calculate the pump- field-induced ...

International Nuclear Information System (INIS)

New non-collinear schemes are suggested for transverse velocity modulation of electron beams and for the generation of coherent spontaneous radiation by these transversely modulated beams. It is shown that due to the non-collinearity some orders of magnitude enhancement can be achieved for the coherent spontaneous radiation (CSR) power at both the fundamental and harmonic frequencies.

UK PubMed Central (United Kingdom)

Mechanisms underlying the release of paclitaxel (PTX) from poly(ethylene glycol)/poly(lactic-co-glycolic acid) (PEG/PLGA) blends were investigated by coherent anti-Stokes Raman scattering (CARS)...Full Text Available

International Nuclear Information System (INIS)

An analytic solution is obtained for the equations of resonance coherent SRS by neglecting the population of the final level of the Raman transition for the systems with the active-medium length that is smaller than the wavelength of the incident light. For the extended systems, a numerical solution is obtained. The energy distribution of the Stokes pulses is found. The large-scale (about 100%) fluctuations of the Stokes radiation energy were observed in the case of unsaturated amplified spontaneous emission. (nonlinear optical phenomena)

Energy Technology Data Exchange (ETDEWEB)

Visual excitation is initiated by the absorption of a photon by the 11-cis retinal chromophore bound within the pigment called rhodopsin. We have used a variety of vibrational spectroscopies to obtain information about the vibrational nuclear dynamics that lead to this efficient photochemical isomerization. The cis-trans isomerization in rhodopsin is complete in only 200 fs. The extreme speed of this process, which is consistent with the {approximately}50 fs lifetime indicated by the spontaneous emission yield, suggests that the photochemistry involves non-stationary states or vibrational coherence. Recent studies have in fact observed vibrationally coherent oscillations of the ground state photoproduct called bathorhodopsin following impulsive excitation of the rhodopsin reactant. This conclusively demonstrates that the isomerization process in rhodopsin is vibrationally coherent. These observations further suggest that ...

CERN Document Server

We report measurements for coherent rho^0 production, AuAu->AuAu rho^0, and coherent rho^0 and e^+e^- pair production accompanied by mutual nuclear Coulomb excitation, AuAu->Au*Au* rho^0 and AuAuee, in ultra-peripheral relativistic gold-gold collisions (UPC). We discuss transverse momentum, mass, and rapidity distributions. The two photon-process of e^+e^- pair production is an important probe of strong field QED because of the large coupling Z*alpha=0.6. At sqrt{s}=200GeV, the e^+e^- production cross section agrees with lowest order QED calculations. The cross sections for coherent rho^0 production at sqrt{s}=130 and 200GeV are in agreement with theoretical predictions. The calculations for both, coherent e^+e^- and rho^0 production treat nuclear excitation as independent process.

British Library Electronic Table of Contents (United Kingdom)

Environmental information has been described as central to the issues of solid waste management and disposal. This study investigated the availability and accessibility of environmental information to the solid waste policy formulators and implementors with regard to the media/channels used for disseminating environmental information to the public. A descriptive survey design was adopted for the study. A purposive sampling technique was used to select the sample and the method produced 205 respondents that consisted of 185 Policy Implementors and 20 Policy Formulators. A total of 147 cases were finally analyzed, which included 16 Policy Formulators (80% of total sample) and 131 Policy Implementors (71% of total sample). Data collected were analyzed using descriptive statistics such as perc...

Energy Technology Data Exchange (ETDEWEB)

This report presents the full texts of the allocution delivered during the colloquium on the renewable energies and the public policies. It takes stock on the strategical environment and the political will of the renewable energies, the tracks of development in France and the necessity of a law on the renewable energies. (A.L.B.)

UK PubMed Central (United Kingdom)

This article explores the effects of reimbursement and utilization control policies on utilization patterns and spending for physician and hospital outpatient services under state Medicaid programs....Full Text Available

Medline Plus

... Mission Research Local Events Advocacy Professional Resources Privacy policy Welcome Back! Use your existing or March for ... or email address Password Forgot username/password Privacy policy Welcome Back! Enter your e-mail address to ...

UK PubMed Central (United Kingdom)

"Correctional Health Care: Implications for Public Health Policy" is the first in a series of articles that examines the special health care needs of persons who are incarcerated in America's correctional...Full Text Available

International Nuclear Information System (INIS)

Both the nature of international climate policy architectures and the development and diffusion of new energy technologies could dramatically influence future costs of reducing global emissions of greenhouse gases. This paper explores the implications of interactions between technology availability and performance and international policy architectures for technology choice and the social cost of limiting atmospheric CO2 concentrations to 500 ppm by the year 2095. Key issues explored in the paper include the role of bioenergy production with CO2 capture and storage (CCS), overshoot concentration pathways, and the sensitivity of mitigation costs to policy and technology.

Science.gov (United States)

Students get a background on Stem Cell technology and learn to write an effective opinion essay.

Science.gov (United States)

... The Defense Logistics Agency (DLA) is responsible for management and administration of the ... 1, Accounting and Finance Manual, and sa N ...

International Nuclear Information System (INIS)

... Labs., Albuquerque, NM (US) GENERAL AND MISCELLANEOUS data

Science.gov (United States)

This article analyzes the philosophical, sociological, and legal imperatives of including students with disabilities in ordinary schools. Some important global events that support inclusive education are discussed. The author reflects on Nigeria's newly revised National Policy on Education with its emphasis on inclusive education (2008), and the Universal Basic Education policy (1999). The article concludes with recommendations to improve the status quo.

Science.gov (United States)

...2010-10-01 2010-10-01 false Energy Policy Act target group certification...Acquisition Regulations System DEPARTMENT OF ENERGY CLAUSES AND FORMS SOLICITATION...Provisions and Clauses 952.226-73 Energy Policy Act target group...

British Library Electronic Table of Contents (United Kingdom)

The Linac Coherent Light Source [1] (LCLS) at SLAC National Accelerator Laboratory is preparing for the arrival of its first scientific users in the fall of 2009. LCLS is the world's first free-electron in the spectral range 800-8,000 eV, producing intense, sub-picosecond pulses of Xrays with very high spatial coherence. The accelerator facility has been commissioned in stages, beginning in April 2007 [2] with the injector linac and culminating in December 2008 [3] with the first transport of electrons through the complete beam path. On April 10, 2009, the LCLS Project team was rewarded for years of planning, design, construction, and checkout with a dream-come-true: as undulators were placed on the beam path one-by-one, the laser simply turned on without drama in the course of one hour [4...

CERN Document Server

Calculations relating to two experiments that demonstrate coherent control of preformed rubidium-85 molecules in a magneto-optical trap using ultrafast laser pulses are presented. In the first experiment, it is shown that pre-associated molecules in an incoherent mixture of states can be made to oscillate coherently using a single ultrafast pulse. A novel mechanism that can transfer molecular population to more deeply bound vibrational levels is used in the second. Optimal parameters of the control pulse are presented for the application of the mechanism to molecules in a magneto-optical trap. The calculations make use of an experimental determination of the initial state of molecules photoassociated by the trapping lasers in the magneto-optical trap and use shaped pulses consistent with a standard ultrafast laser system.

UK PubMed Central (United Kingdom)

Advances in molecular technologies challenge the different concepts of causality in biology, epidemiology and multistage mathematical models. The lack of integration of the different aspects of causality...Full Text Available

UK PubMed Central (United Kingdom)

Periventricular white matter injury (PWMI), is the leading cause of chronic neurologic injury among survivors of preterm birth. The hallmark of PWMI is hypomyelination and a lack of mature,...Full Text Available

UK PubMed Central (United Kingdom)

The physical demands of performing on musical instruments can cause pain, sensory loss, and lack of coordination. Five cases illustrate common problems. Knowledge of the interaction between the technique...Full Text Available

UK PubMed Central (United Kingdom)

The cause of the female urethral syndrome has previously been obscure, as it has been associated by definition with a lack of objective findings but a plethora of subjective complaints of retropubic...Full Text Available

International Nuclear Information System (INIS)

A report is given of a meeting of the Netherlands Association for Energy Legislation (NEVER), which was held in Amsterdam, Netherlands, April 2006. After the meeting a presentation was made about the report 'Government involvement in liberalised gas markets. A welfare-economic analysis of the Dutch gas-depletion policy' of the Netherlands Bureau for Economic Policy Analysis (CPB). This report analyses the welfare effects of two major components of the Dutch gas-depletion policy: the offtake guarantee for small-fields gas and the cap on production from the Groningen field. After the presentation a reaction was given to the report. Both presentations give an overview of the governmental policy and insight in the effects.

Energy Technology Data Exchange (ETDEWEB)

U.S. nuclear policy has become the target of increasing criticism during the past decade. Critics often argue that the use of nuclear weapons would be irrational, would destroy humankind, and thus could not serve any rational policy goal. Other critics point to the immortality of the use of nuclear weapons. Both groups condemn U.S. military policy. In Nuclear War, James Child considers and rejects both these lines of criticism. He argues that a policy of deterrence can be both rational and moral; that U.S. nuclear policy is, on balance, based on rational and moral foundations. Child examines near-term consequences of a nuclear war and finds them ghastly but not unthinkable or incomparable to the havoc produced by previous wars. He also analyzes long-term consequences, such as those proposed by the ''nuclear winter'' theory, and finds the fear of ...

UK PubMed Central (United Kingdom)

Meso- and submesoscales (fronts, eddies, filaments) in surface ocean flow have a crucial influence on marine ecosystems. Their dynamics partly control the foraging behavior and the displacement of marine...Full Text Available

Science.gov (United States)

We investigate the features of the spontaneous emission spectra in a coherently driven cold five-level atomic system by means of a radio frequency (rf) or microwave field driving a hyperfine transition within the ground state. It is shown that a few interesting phenomena such as spectral-line narrowing, spectral-line enhancement, spectral-line suppression, and spontaneous emission quenching can be realized by modulating the frequency and intensity of the rf-driving field in our system. In the dressed-state picture of the coupling and rf-driving fields, we find that this coherently driven atomic system has three close-lying levels so that multiple spontaneously generated coherence (SGC) arises. Our considered atomic model can be found in real atoms, such as rubidium or sodium, so a corresponding experiment can be done to observe the expected phenomena related to SGC reported by Fountoulakis et al. [Phys. Rev. A 73, 033811 ...

International Nuclear Information System (INIS)

A scheme is presented for the generation of entangled states for two cavity mirrors. In the scheme each mirror initially in a vacuum state interacts with a weak coherent field, resulting in a photon-number dependent kick. The detection of a photon leaking from the cavities collapses the two mirrors to an entangled state.

UK PubMed Central (United Kingdom)

Spike-timing-dependent plasticity (STDP), a form of Hebbian plasticity, is inherently stabilizing. Whether and how GABAergic inhibition influences STDP is not well understood. Using a model neuron driven...Full Text Available

Science.gov (United States)

Analytical method of theoretical simulation of collective hydrodynamic instabilities of intensive flows of discrete radiators, interacting with each other only through the coherent fields of their spontaneous radiation in corresponding media was suggested...

UK PubMed Central (United Kingdom)

PurposeTo determine the effects of age on global and sectoral peripapillary retinal nerve fiber layer (RNFL), macular thicknesses and optic nerve head (ONH) parameters...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Algebraic properties of the analytical model, describing electro-magnetic weak interaction with the two-level system with two-fold degenerate state are considered. The expressions for the coherent states and Green function of the system are obtained.

International Nuclear Information System (INIS)

A new kind of e-beam bunching enabling the production of coherent spontaneous emission (CSE) is proposed and considered. It is shown that an e-beam in passing through an undulator will induce CSE along with incoherent spontaneous radiation on the same wavelength if the e-beam transverse velocity is modulated with a spatial period twice as long as the radiation wavelength. Such angular modulated beams can be regarded as alternatives to conventionally density modulated beams for CSE production. Requirements for e-beams are similar in both cases.

International Nuclear Information System (INIS)

A ''coherent flucton'' nuclear model is proposed which provides for new possibilities for particle scattering studies on nuclei. It is based on the data of nuclear matter density distribution and is used for calculating the ground state energy of Fermi system terminals. The ''coherent flucton'' model is applied to the distribution of 1 GeV protons on "2"8Si, "3"2S, "4"0Ca, "4"8Ca, "5"8Ni, "2"0"8Pb nuclei. The calculations by the model agree well with experimental data.

British Library Electronic Table of Contents (United Kingdom)

Epitaxial thin films of nanotwinned face-centered cubic metals such as Cu possess an unprecedented combination of high hardness and high electrical conductivity due to the unique structure of nanometer-spaced coherent twin boundaries. Recent studies of in-situ nanoindentation in a transmission electron microscope have provided new insights on the deformation behavior of nanotwins that are reviewed here. In particular, two unit processes are highlighted: first, stress-induced migration of ?3 {112} incoherent twin boundary that leads to de-twinning of nanotwins; second, twinning dislocation can be multiplied at ?3 {111} coherent twin boundary.

Science.gov (United States)

We outline the process for determining the morphology of subsurface epithelial cell nuclei using depth-resolved light scattering measurements. The measurements are accomplished using a second generation angle-resolved low coherence interferometry system. The new system greatly improves data acquisition and analysis times compared to the initial prototype system. The calibration of the new system is demonstrated in scattering studies to determine the size distribution of polystyrene microspheres in a turbid sample. The process for determining the size of cell nuclei is discussed by analyzing measurements of basal cells in a sub-surface layer of intact, unstained epithelial tissue.

Energy Technology Data Exchange (ETDEWEB)

Objectives: To investigate optical coherence tomography consistency on foveal thickness, foveal volume, and macular volume measurements in patients with and without diffuse diabetic macular edema. Introduction: Optical coherence tomography represents an objective technique that provides cross-sectional tomographs of retinal structure in vivo. However, it is expected that poor fixation ability, as seen in diabetic macular edema, could alter its results. Several authors have discussed the reproducibility of optical coherence tomography, but only a few have addressed the topic with respect to diabetic maculopathy. Methods: The study recruited diabetic patients without clinically evident retinopathy (control group) and with diffuse macular edema (case group). Only one eye of each patient was evaluated. Five consecutive fast macular scans were taken using Ocular Coherence Tomography 3; the 6 mm macular map ...

Energy Technology Data Exchange (ETDEWEB)

Renewable Energy Technologies (RETS) have over the years become an integral part of the energy supply chain in most developed countries. Recent projections show that 13.5% of the world's primary energy supply comes from renewable and this figure has an aggregated annual growth rate of 16%. Wind has the highest annual growth rate of 22% while the least annual growth rate of 2% is for hydropower. The main push for renewable like wind in the OECD countries are environmental concerns and the business aspect in power generation. The situation is however completely different in Africa, where the thrust for RETs is developmental based. Although the continent has abundant renewable energy resources like solar, biomass, wind and hydro potential, they have remained largely unexploited. Several efforts have been made to help African countries like Zimbabwe to exploit such resources. The main objectives of this country study included review of Zimbabwe's development of past RETs, ...

Energy Technology Data Exchange (ETDEWEB)

National environmental policies have international repercussions: Thus the question arises as to how environmental policy should be designed in order to cope with international environmental problems in an efficient way. These topics were discussed in a conference held at the Kiel Institute of World Economics on July 5-6, 1990. The conference papers and comments are presented in this volume. Environmental scarcity has important international aspects. First, national environmental endowment and policy influence competitiveness and trade. Second, transfrontier pollution is a specific issue. Third, global environmental problems require a solution. This classification of the international aspects of the environmental issue provides the outline of the book. (orig./HSCH).

British Library Electronic Table of Contents (United Kingdom)

This article presents a linear-analytical case study on the development of ICT within the educational systems of Chile and South Korea. Through a comprehensive meta-data analysis and bibliographic review, we collected information on both educational systems and their ICT adoption policies. Key differences necessary to understand how both countries have developed their educational systems by integrating ICT were analyzed, including the educational system structure, the organization of state entities responsible for educational ICT, cultural characteristics, the creation of policies regarding ICT in education, and the effectiveness of such policies for the expansion of infrastructure and the ICT curriculum integration. We analyze these key differences in order to understand two cases of ICT ...

British Library Electronic Table of Contents (United Kingdom)

I formulate a model in which money coexists with equity shares on a risky aggregate endowment. Agents can use equity as a means of payment, so shocks to equity prices translate into aggregate liquidity shocks that disrupt the mechanism of exchange. I characterize a family of optimal monetary policies and find that the resulting equity prices are independent of monetary considerations. I also study a perturbation of the family of optimal policies that targets a positive constant nominal interest rate and find that in this case the real equity return includes a liquidity return that depends on monetary considerations.

Science.gov (United States)

... 3122.01A, Joint Operation Planning and Execution System (JOPES) Volume I, Planning Policies and Procedures (Sept. 29, 2006) and CJCSM ...

International Nuclear Information System (INIS)

Enhancing transport sustainability is the password of national, European, and international policies. The development of innovative solutions is ranging from bio fuels to transport analysis models, materials, traction technologies, mobility management, freight villages.

Science.gov (United States)

... PDOD on region- wide SC policy and initiatives, and would liaise with their COCOM colleagues (including the embedded ...

Science.gov (United States)

... terminals, popular tourist spots, political rallies, and subway ... Dynamic scheduling of a two-class queue with ... Stochastic Processes 2nd ed. Wiley. ...

Science.gov (United States)

we have a colloquium scheduled. Computing: register your machine and check our network security and visitor computer policies. For Our Information: Once arranged, please let us...

Science.gov (United States)

may experience difficulty opening the Facebook page due to current HHS policy and network security that blocks access to the site. Site Map - Contact Us - Linking to USPHS.gov -...

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...policy issues global warming global climate change ? there's a famous hockey ...global warming the greatest hopes for betray them and kind of forgotten ...

UK PubMed Central (United Kingdom)

The obligations of organisations associated with policy formation and implementation of international mass public health programmes are explored. Lines of responsibility are considered to become unclear...Full Text Available

Science.gov (United States)

The Global Warming International Center (GWIC) is the international body disseminating information on global warming science and policy, serving both governamental, non-governamental ... ...

British Library Electronic Table of Contents (United Kingdom)

The approval (2003) and enforcement (2005) of a smoking ban in Italy have been viewed by many as an unexpectedly successful example of policy change. The present paper, by applying a processualist approach, concentrates on two policy cycles between 2000 and 2005. These had opposing outcomes: an incomplete decisional stage and an authoritative decision, enforced two years later. Through the analysis of the different phases of agenda setting, alternative specification and decision making, we have compared the quality of participation of policy entrepreneurs in the two cycles, their political strategies and, in these, the relevance of issue image. The case allows us to direct the attention of scholars and practitioners to an early phase of the policy implementation process - which we have nam...

Science.gov (United States)

Government policies that encourage exploitation--in particular excessive logging and clearing for ranches and farms--are largely to blame for the accelerating destruction of tropical forests. This paper surveys the problem in detail and briefly recommends potential solutions.

UK PubMed Central (United Kingdom)

SUMMARYIncreasingly multiple outcomes are collected in order to characterize treatment effectiveness or to evaluate the impact of large policy initiatives. Often the multiple...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This paper uses selection criteria from various models in a bounds testing approach to cointegration to estimate the price and income elasticities of demand for total petroleum products (gasoline and diesel) and gasoline share in total products in Indonesia. The results suggest that both total products and gasoline share estimates are more responsive to changes in income than changes in the real price of petroleum products. These results have important policy implications as they suggest that policy makers may need to use market-based pricing policies and other policies such as public enlightenment in addition to regulations like minimum energy efficiency standards to promote efficiency and conservation and curb the rising consumption of petroleum products in Indonesia. (author)

UK PubMed Central (United Kingdom)

BackgroundThe evaluation of interventions and policies designed to promote resilience, and research to understand the determinants and associations, require reliable and valid measures...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Recently there has been growth, in interest in non-equilibrium interaction of half-period long optical pulses with matter. To date the optical pulses have been produced by chopping out a half-period long segment from a longer pulse using a semiconductor switch driven by a femtosecond laser. In this paper we present new methods for producing tunable ultra-short optical pulses as short as half an optical period using a free-electron laser driven by electron bunches with a duration a fraction of an optical period. Two different methods relying on the production of coherent spontaneous emission will be described. In the first method we show that when a train of ultra-short optical pulses as short as one half period. We present calculations which show that the small signal gain is unimportant in the early stages of radiation build up in the cavity when the startup process is dominated by coherent spontaneous emission. To support our proposed method ...

Energy Technology Data Exchange (ETDEWEB)

The development of modern techniques for the cooling and the manipulation of atoms in recent years, and the possibility to create Bose-Einstein condensates and degenerate Fermi gases and to load them into regular optical lattices or disordered optical potentials, has evoked new interest for the disorder-induced localization of ultra-cold atoms. This work studies the transport properties of matter waves in disordered optical potentials, which are also known as speckle potentials. The effect of correlated disorder on localization is first studied numerically in the framework of the Anderson model. The relevant transport parameters in the configuration average over many different realizations of the speckle potential are then determined analytically, using self-consistent diagrammatic perturbation techniques. This allows to make predictions for a possible experimental observation of coherent transport phenomena for cold atoms in speckle potentials. Of particular ...

International Nuclear Information System (INIS)

A model for coherent fluctuations of the nuclear density including all nucleons in the fluctuation movement is formulated. The wave function of the flucton satisfies a Schroedinger-type equation in which the role of potential energy is played by the energy of the nuclear matter for the A nucleons. The appearance of high-momentum components in the one-particle momentum distribution is related to the volume fluctuations of the density. These fluctuations are supposed to be of coherent nature, i.e. all nucleons are involved in the motion. An explicit expression for the momentum distribution of the nucleons in "1"2C and "1"8"1Ta nuclei is obtained and compared with the phenomenological momentum distribution as well as with the results given by the model of a non-relativistic harmonic oscillator and by the Dirac equation in the self-consistent model. The differential cross-section of 1 GeV proton scattering by the "2"8Si, "3"2S, "4"0Ca, "4"8Ca, ...

UK PubMed Central (United Kingdom)

BackgroundMany studies have evaluated the accuracy of dipstick tests as rapid detectors of bacteriuria and urinary tract infections (UTI). The lack of an adequate explanation for...Full Text Available

UK PubMed Central (United Kingdom)

OBJECTIVE--To assess the accuracy of the ten questions screen as a measure of childhood disability for epidemiologic studies in populations lacking resources for professional assessment of children's...Full Text Available

UK PubMed Central (United Kingdom)

Patients with Alport syndrome progressively lose renal function as a result of defective type IV collagen in their glomerular basement membrane. In mice lacking the α3 chain of type IV collagen...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundThere is a lack of studies considering social disparity in oral health emanating from adolescents in low-income countries. This study aimed to assess socio-demographic...Full Text Available

UK PubMed Central (United Kingdom)

During a study of the health status of children in rural Nigerian communities a gross lack of fit was observed between the sample and the growth attainment standards derived from local longitudinal...Full Text Available

UK PubMed Central (United Kingdom)

Development of mouse models representing human spontaneous ovarian cancer has been hampered by the lack of understanding of the etiology of this very complex disease. Mouse models representing the different...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundThe lack of adequate randomized clinical trials (RCT) has hindered identification of new therapies that are safe and effective for patients with primary focal segmental...Full Text Available

UK PubMed Central (United Kingdom)

Various hypotheses have been proposed to explain the molecule processes of sarcomere assembly, partially due to the lack of systematic genetic studies of sarcomeric genes in an in vivo...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A mechanistic understanding of fracture in human bone is critical to predicting fracture risk associated with age and disease. Despite extensive work, a mechanistic framework for describing how the underlying microstructure affects the failure mode in bone is lacking.

Energy Technology Data Exchange (ETDEWEB)

This study examines some radiation accidents occurred in the past. This information has been systematically assessed to get global lessons. The experience feedback shows that the most of accidents happened in certain conditions. These conditions can be distributed in four categories: 1- perception and vigilance in occupation: accidental exposure happened by lack of vigilance in details and lack of vigilance and perception; 2- procedures: accidental exposure happened following a lack of procedures or control that were not enough complete, not enough documented or not completely implemented; 3- training and understanding: accidental exposures happened because the personnel was not enough qualified and educated, did not get the general training nor the the necessary specialized training; 4- liabilities: accidental exposures happened following lacks and ambiguity in the definition of functions of the ...

UK PubMed Central (United Kingdom)

Dysregulation of the alternative pathway of complement activation, caused by mutations or polymorphisms in the genes encoding factor H, membrane co-factor protein, factor I or factor B, is associated...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundChildhood is a high risk time for ultraviolet induced skin damage as this age group has more time and opportunity to be outdoors in the sun. Children in Africa with the...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundApolipoprotein E (ApoE), a cholesterol carrier associated with atherosclerosis, is a major risk factor for Alzheimer's disease (AD). The low-density lipoprotein receptor...Full Text Available

UK PubMed Central (United Kingdom)

Disruption of circadian rhythms may be involved in the pathophysiology of psychiatric disorders, including drug addiction. Recently, we detected the significant association between prokineticin 2 receptor...Full Text Available

UK PubMed Central (United Kingdom)

BACKGROUND: Although the importance of lymphatic function is well recognized, the lack of real-time imaging modalities limits our understanding of its role in many diseases. In a phase...Full Text Available

UK PubMed Central (United Kingdom)

Purpose of reviewSevere congenital neutropenia (SCN) is a primary immunodeficiency in which lack of neutrophils causes inadequate innate immune host response to bacterial...Full Text Available

UK PubMed Central (United Kingdom)

DNA double-strand breaks (DSBs) are generally accepted to be the most biologically significant lesion by which ionizing radiation causes cancer and hereditary disease. However, no information on the...Full Text Available

UK PubMed Central (United Kingdom)

Current methods of detecting confidentiality breaches in electronic medical record systems are inadequate, partially due to the lack of necessary information at the point of audit trail analysis. In...Full Text Available

UK PubMed Central (United Kingdom)

Carney-Stratakis syndrome, an inherited condition predisposing affected individuals to gastrointestinal stromal tumor (GIST) and paraganglioma, is caused by germline mutations in succinate dehydrogenase...Full Text Available

UK PubMed Central (United Kingdom)

IntroductionAutologous chondrocyte transplantation (ACT) is a routine technique to regenerate focal cartilage lesions. However, patients with osteoarthritis (OA) are lacking an appropriate...Full Text Available

UK PubMed Central (United Kingdom)

Scoping studies have been used across a range of disciplines for a wide variety of purposes. However, their value is increasingly limited by a lack of definition and clarity of purpose. The UK's Service...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundMany commercial banana varieties lack sources of resistance to pests and diseases, as a consequence of sterility and narrow genetic background. Fertile wild relatives,...Full Text Available

UK PubMed Central (United Kingdom)

BackgroundClassification systems may be useful to direct more aggressive treatment to cancer patients with a relatively poor prognosis. The definition of 'poor prognosis' often lacks...Full Text Available

Science.gov (United States)

The chemist and pharmacologist Fritz Hauschild developed the sympathomimetic agent Pervitin (metamphetamin) in the 1930s. Not only because of the abuse of the stimulant during the Second World War ("pilot's chocolate") it is one of the most controversial substances in drug history. Nearly forgotten are Hauschild's contributions to build up the drug system in the GDR. Although he was a convinced communist, the skilful pharmacologist gave very early warning of the imminent lack of innovation in the GDR pharmaceutical industry. A letter which he addressed to the Minister of Health, Max Sefrin (born 1913), did not lack explicitness. PMID:15997840

British Library Electronic Table of Contents (United Kingdom)

AbstractObjective To review studies investigating the brain correlates of unawareness of cognitive and behavioural symptoms in people with dementia. Design A detailed search of the literature was conducted to include all the peer-reviewed studies published in English aimed at identifying the structural or functional brain correspondents of unawareness in dementia patients. Their results were interpreted in relation to the methodological differences in terms of type of dementia studied, the protocol adopted to measure lack of awareness, the imaging techniques employed, the experimental designs and statistical analyses performed. Results Eighteen studies undertaken to explore the functional and structural correlates of unawareness of cognitive symptoms in dementia were identified. Although t...

Energy Technology Data Exchange (ETDEWEB)

Energy sector is relatively easy to evaluate economically. There have existed reliable statistics on energy systems and consumption and the planning has been based on them. However the environmental factors have been integrated into the Danish energy policy first in the nineties, and the new socio-economic evaluations have to take the pollution abatement measures into account. (EG)

UK PubMed Central (United Kingdom)

Introduction:Exposure to secondhand smoke causes premature death and disease in non-smokers and indoor smoke-free policies have become increasingly prevalent worldwide. Although...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The aim of this report is to show how Energetic Planning and Territorial Policy should be working together for a better integration of Renewable Energies into Region. This Integration should to contemplate social, economic and environmental aspects of the territory. The report has been classified into 7 items: planning, energetic scenarios, technology transfer for Renewable Energies dissemination, barriers for this dissemination, environmental aspects, European Union Policy and Decision Support Systems (and specially GIS). (Author) 54 refs.

Energy Technology Data Exchange (ETDEWEB)

Designing efficient policies for curbing greenhouse gas (GHG) emissions is of particular interest for todays policy makers, in view of global climate change threats. This paper analyses the options Switzerland has for curbing its CO{sub 2} emissions. Using MARKAL and MARKAL-NACRO models, it investigates, in particular effects of national and international carbon taxes. (author) 3 figs., 1 tab., 6 refs.

Wastenet

...Older Siblings by Adriaan R Soetevent & Peter Kooreman 392-415 Vocational Training and Gender: Wages and Occupational Mobility among Young Workers by Bernd Fitzenberger & Astrid Kunze 416-438 Gender Role Attitudes and the Labour-market Outcomes of Women across OECD Countries by Nicole M Fortin 439-461 Gender, Time Use, and Public Policy over ...

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... Hale, Markku Kulmala, 373.43 EUR; 225.00 USD; 276.00 GBP... Light Scattering Media Optics Alexander A. Kokhanovsky 159.00 USD; 123.00 EUR; 103.50 GBP... More Journals » MAGAZINES & JOURNALS Water Policy - Official Journal of the World... Water Policy publishes reviews, research papers... ...

British Library Electronic Table of Contents (United Kingdom)

Abstract In this paper, the effect of several turbulence parameters during various flow conditions in Owens Valley, educed from coherent Doppler lidar data have been studied. Radial velocity structure functions are processed to estimate the turbulent kinetic energy (TKE) dissipation rate, integral length scale and velocity variance, assuming a theoretical model for isotropic wind fields. Corrections for turbulence measurements have been considered to address the complications due to inherent volumetric averaging of radial velocity over each range gate, noise of the lidar data, and the assumptions required to estimate effects of smaller scales of motion on turbulence quantities. Using data from the Terrain-induced Rotor Experiment (T-REX) in April-May 2006, vertical profiles of wind and tur...

Science.gov (United States)

The excess energy of several III-V and II-VI strained-layer semiconductor superlattices ({ital AC}){sub {ital p}}(BC){sub p} is studied as a function of the repeat period {ital p} and orientation {bold G}=(001), (110), (111), and (201), using first-principles calculations. We discover a number of universal features, including the predicted instability for nearly all {ital p}'s and {bold G}'s with respect to {ital bulk} disproportionation, the identification of chalcopyrite as a metastable ordered structure, and the stability of all thin {ital epitaxial} (110) and (201) and most common-anion (001) superlattices relative to coherent phase separation.

Energy Technology Data Exchange (ETDEWEB)

The Linac Coherent Light Source (LCLS) will be the world's first x-ray free-electron laser (FEL). To ensure the vitality of FEL lasing, it is critical to preserve the high quality of the electron beam during acceleration and compression. The peak current and final energy are very sensitive to system jitter. To minimize this sensitivity, a longitudinal feedback system on the bunch length and energy is required, together with other diagnostics and feedback systems (e.g., on transverse phase space). Here, we describe a simulation framework, which includes a realistic jitter model for the LCLS accelerator system, the RF acceleration, structure wakefield, and second order optics. Simulation results show that to meet the tight requirements set by the FEL, such a longitudinal feedback system is mandatory.

International Nuclear Information System (INIS)

In a seeded high-gain free-electron laser (FEL), where a coherent laser pulse interacts with an ultrarelativistic electron beam, the seed laser pulse can be frequency chirped, and the electron beam can be energy chirped. Besides these two chirps, the FEL interaction introduces an intrinsic frequency chirp in the FEL even if the above-mentioned two chirps are absent. We examine the interplay of these three chirps. The problem is formulated as an initial value problem and solved via a Green function approach. Besides the chirp evolution, we also give analytical expressions for the pulse duration and bandwidth of the FEL, which remains fully longitudinally coherent in the high-gain exponential growth regime. Because the chirps are normally introduced for a final compression of the FEL pulse, some conceptual issues are discussed. We show that to get a short pulse duration, an energy chirp in the electron beam is important.

Energy Technology Data Exchange (ETDEWEB)

The coherent flucton model is applied to the description of some basic nuclear properties, such as: ground state energies, bond energies, nucleon momentum spectra, and nuclear density distributions. It is shown that the momentum distributions of the nucleons coincide with the Fermi distribution for small momenta and exhibit a well pronounced high energy ''tail'', thus providing inclusive reactions of pi-meson generations in kinematically forbidden areas at nucleon-nucleon collisions. Analytical expressions for the bond energy and nuclear density distribution are derived. An agreement with the experimentally obtained data is achieved. The model features are discussed referring to the processes, characterized mainly by the geometric and dynamic properties of the nuclei, as well as by nuclear density distribution. In particular, ion-ion scattering processes at high energy are considered.

International Nuclear Information System (INIS)

We obtain and investigate the regular eigenfunctions of simple differential operators xr dr+1/dxr+1, r = 1, 2, ..., with the eigenvalues equal to 1. With the help of these eigenfunctions, we construct a non-unitary analogue of a boson displacement operator which will be acting on the vacuum. In this way, we generate collective quantum states of the Fock space which are normalized and equipped with the resolution of unity with the positive weight functions that we obtain explicitly. These states are thus coherent states in the sense of Klauder. They span the truncated Fock space without first r lowest-lying basis states: |0), |1), ..., |r - 1). These states are squeezed, sub-Poissonian in nature and reminiscent of photon-added states in Agarwal and Tara (1991 Phys. Rev. A 43 492).

Energy Technology Data Exchange (ETDEWEB)

We propose and analyze a novel regenerative amplifier free electron laser (FEL) to produce fully coherent x-ray pulses. The method makes use of narrow-bandwidth Bragg crystals to form an x-ray feedback loop around a relatively short undulator. Self-amplified spontaneous emission (SASE) from the leading electron bunch in a bunch train is spectrally filtered by the Bragg reflectors and is brought back to the beginning of the undulator to interact repeatedly with subsequent bunches in the bunch train. The FEL interaction with these short bunches not only amplifies the radiation intensity but also broadens its spectrum, allowing for effective transmission of the x-rays outside the crystal bandwidth. The spectral brightness of these x-ray pulses is about two to three orders of magnitude higher than that from a single-pass SASE FEL.

International Nuclear Information System (INIS)

Coherent Smith-Purcell radiation, emitted from short-bunched electrons passing by a lamellar-type grating of aluminum, has been observed in the millimeter wave region. The energy of the electrons is either 42 MeV when they are accelerated by an L-band linear accelerator or 150 MeV accelerated by an S-band one. The intensity of the radiation is proportional to the square of the beam current. The radiation is linearly polarized, and the electric vector of the radiation is in the plane defined by the observing point and the beam trajectory. The intensity decreases with the beam height, i.e. the distance of the beam from the surface of the grating, in accordance with the modified Bessel function of zeroth order. copyright 1996 American Institute of Physics.

CERN Document Server

We present a single solid-state laser system to cool, coherently manipulate and detect $^{25}$Mg$^+$ ions. Coherent manipulation is accomplished by coupling two hyperfine ground state levels using a pair of far-detuned Raman laser beams. Resonant light for Doppler cooling and detection is derived from the same laser source by means of an electro-optic modulator, generating a sideband which is resonant with the atomic transition. We demonstrate ground-state cooling of one of the vibrational modes of the ion in the trap using resolved-sideband cooling. The cooling performance is studied and discussed by observing the temporal evolution of Raman-stimulated sideband transitions. The setup is a major simplification over existing state-of-the-art systems, typically involving up to three separate laser sources.

Energy Technology Data Exchange (ETDEWEB)

The report examines the scientific progress which has been made over the past years on the climate change issue. It examines shifts in emphasis on climate change debates and the implications of scientific uncertainty for the policy maker. Information on the impact of climate on various sectors, such as agriculture and coastal zones is also provided, as well as a case study on the UK. Regional impacts of climate change and associated economic implications are considered. The report also documents some different considerations for a climate change policy in the context of the latest meeting of contracting parties to the Un Framework Convention on Climate Change, held in Kyoto in December 1997. The report is divided into five sections: Introduction; Scientific progress; Climate change policy - the dilemma with implementation; Summary and conclusions; Summary of Kyoto`s results. 146 refs., 4 figs., 14 tabs., 2 apps.

International Nuclear Information System (INIS)

The method of inversion of the eigenvalue problem previously developped for nuclei with axial symmetry is extended to asymmetric equilibrium shapes. This new approach to the asymmetric rotator model is applied to the odd-mass Iridium isotopes. A satisfactory and coherent description of the observed energy spectra is obtained, especially for the lighter isotopes. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Microscopic non-energy weighted sum-rules for the total rates of the neutrinoless ..mu..-e conversion process are constructed in the frame of the shell model for closed shell nuclei. For non-closed shell nuclei the relevant rates were obtained by interpolation. Also the contribution of the coherent process to the total ..mu..-e conversion rate is calculated and discussed.

International Nuclear Information System (INIS)

We report the homodyne detection of phase modulation sidebands induced on a laser beam by a coherently bunched electron beam. This provides a sensitive and nonperturbing measurement of complex Fourier time series components of the electron density. A proof-of-principle measurement of the microwave frequency component of electron density in a crossed-field device, which agrees well with a calculation of the same quantity, is reported.

International Nuclear Information System (INIS)

This review briefly describes current efforts to develop superradiant sources of coherent radiation for the sub-nanometer range of wavelenghs, using nuclear rather than the atomic or molecular transitions that are stimulated in existing lasers. First the radiative (including Raman) interactions of nuclei with those of atoms and molecules are compared; then the present status of research on the fundamental problems involved in stimulating nuclear gamma radiation is described. (author). 20 refs.; 2 figs.

Science.gov (United States)

Spike-timing-dependent plasticity (STDP), a form of Hebbian plasticity, is inherently stabilizing. Whether and how GABAergic inhibition influences STDP is not well understood. Using a model neuron driven by converging inputs modifiable by STDP, we determined that a sufficient level of inhibition was critical to ensure that temporal coherence (correlation among presynaptic spike times) of synaptic inputs, rather than initial strength or number of inputs within a pathway, controlled postsynaptic spike timing. Inhibition exerted this effect by preferentially reducing synaptic efficacy, the ability of inputs to evoke postsynaptic action potentials, of the less coherent inputs. In visual cortical slices, inhibition potently reduced synaptic efficacy at ages during but not before the critical period of ocular dominance (OD) plasticity. Whole-cell recordings revealed that the amplitude of unitary IPSCs from parvalbumin positive (Pv+) interneurons to ...

British Library Electronic Table of Contents (United Kingdom)

Abstract This article advocates that some form of personal immortality is not only taught in F.D.E. Schleiermacher's Glaubenslehre but is also necessary for the coherence of the same work. The combination of a naturalized account of redemption, a commitment to universal salvation and the realist observation that some never know Christ in this life causes Schleiermacher to posit a certain but content-free afterlife to account for the discrepancy.

International Nuclear Information System (INIS)

This paper discusses the concept of controllable subspace for open quantum dynamical systems. It is constructively demonstrated that combining structural features of decoherence-free subspaces with the ability to perform open-loop coherent control on open quantum systems will allow decoherence-free subspaces to be controllable. This is in contrast to the observation that open quantum dynamical systems are not open-loop controllable. To a certain extent, this paper gives an alternative control theoretical interpretation on why decoherence-free subspaces can be useful for quantum computation.

International Nuclear Information System (INIS)

The subject of quantum optics has undergone considerable development in the last twenty-five years. Spurred by the invention of the laser, the theoretical understanding of the coherence and statistical properties of optical beams has now attained a stage of maturity where it is possible to treat different kinds of light sources. Over approximately the latter half of this period of development in quantum optics, the free-electron laser (FEL) has been developed to the point where it is now regarded as a tunable light source of considerable versatility, with prospects of producing radiation over a wide range of wavelengths at large levels of power. Since the basic mechanism for radiation gain in an FEL can be understood in classical terms, much of the literature on the subject does not need to venture outside the domain of classical physics. However, it is natural that the coherence and statistical properties of photon beams produced by FEL's ...

British Library Electronic Table of Contents (United Kingdom)

The prevention of subscriber churn through customer retention is a core issue of Customer Relationship Management (CRM). By minimizing customer churn a company maximizes its profit. This paper proposes a hybridized architecture to deal with customer retention problems. It does so not only through predicting churn probability but also by proposing retention policies. The architecture works in two modes: learning and usage.In the learning mode, the churn model learner seeks potential associations from the subscriber database. This historical information is used to form a churn model. This mode also calls for a policy model constructor to use the attributes identified in the churn model to divide all `churners' into distinct groups. The policy model constructor is also responsible for develop...

British Library Electronic Table of Contents (United Kingdom)

From its inception in 1977, the U.S. Department of Energy (DOE) has been responsible for maintaining the nations nuclear stockpile, leading the country in terms of basic research, setting national energy goals, and managing thousands of individual programs. Despite these gains, however, the DOE research and development (R&D) model does not appear to offer the nation an optimal strategy for assessing long-term energy challenges. American energy policy continues to face constraints related to three "Is": inconsistency, incrementalism, and inadequacy. An overly rigid management structure and loss of mission within the DOE continues to plague its programs and create inconsistencies in terms of a national energy policy. Various layers of stove-piping within and between the DOE and national labo...

International Nuclear Information System (INIS)

Full text.The electric energy demand in Lebanon is estimated to grow at an average of 3-5% per year for the coming 10 years. Such an increase in energy demand is problematic for Lebanon since its economy is almost totally dependent on imported fuel which contributes to 97% of the overall energy requirements. Solar water heaters (SWH) are regarded as the most important element in a long term energy conservation and management strategy for this country, but their promotion is a national issue requiring the participation of many stake holders and decision makers. Additionally, the success of solar energy penetration into the existing energy market is constrained by many factors such as technical and financial limitations, decision criteria and policy instruments. This paper will explore the feasibility of SWH, and will work out, using the Analytic Hierarchy Process technique, a policy to ensure a large scale diffusion of SWH in the energy market

Energy Technology Data Exchange (ETDEWEB)

There is a clear incentive, therefore, for early consideration of the measures required to meet noise and vibration standards. The platform or rig owner and the operator are jointly responsible for agreeing a noise and vibration control policy and approach at the conceptual design stage, and for then passing on their requirements to the engineering design teams. The engineering design teams and acoustic and vibration specialists for their part need to use all their skill and judgement to apply that policy to the intensely complex job of designing and fabricating topsides facilities. With these concerns as background, UEG started, and has nearly completed, a two-phase study to provide detailed guidance to project managers and designers to assist them to develop appropriate policy and procedures and to help them put those procedures into practice. This paper describes the development of UEG's study, its application ...

Science.gov (United States)

... s the matter with Kansas?Legislative debates over stem cell research in Kansas and MassachusettsBonnie StabileSchool of Public Policy, ... examines the contextual factors shaping legislative debates affec...

UK PubMed Central (United Kingdom)

Man-made endocrine-disrupting chemicals (EDCs) present a threat to biodiversity, even in remote areas. To date, numerous wildlife species have been affected by EDCs in the environment, but it is likely...Full Text Available

UK PubMed Central (United Kingdom)

In a "nutrition transition", the consumption of foods high in fats and sweeteners is increasing throughout the developing world. The transition, implicated in the rapid rise of obesity and diet-related...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This study compares the attitudes of academic and government wetlands scientists about wetlands science and policy. Analysis of one thousand seven hundred responses to Delphi-type questions posed to twenty California scientists on a wide range of issues about California coastal wetlands found significant differences between academic and government scientists about wetlands definitions, threats to wetlands, wetlands policies, wetlands health, and wetlands mitigation strategies. These differences were consistent with descriptive models of political sociology developed by D. Price and C.P. Snow and with normative models of the philosophy of science developed in the renaissance by F. Bacon and R. Descartes. Characteristics, preferences, and personality attributes consistent with group functions and roles have been described in these models. These findings have serious implications for policy. When academic and government ...

UK PubMed Central (United Kingdom)

Invasive species are increasingly becoming a policy priority. This has spurred researchers and managers to try to estimate the risk of invasion. Conceptually, invasions are dependent both on the receiving...Full Text Available

Wastenet

... The main goal was the analysis of the Environmental Kuznets Curve hypothesis for the Czech Republic. A paper by Bruha and Scasny, accepted to the European Society of Ecological Economics, ( Lisbon June 2005), analyses driving forces (including economic policy) on ...

UK PubMed Central (United Kingdom)

The proliferation of stem cell research, conflated with its ethical and moral implications, has led governments to attempt regulation of both the science and funding of stem cells. Due to a diversity...Full Text Available

UK PubMed Central (United Kingdom)

IntroductionResearch is an essential tool in facing the challenges of scaling up interventions and improving access to services. As in many other countries, the translation of research...Full Text Available

UK PubMed Central (United Kingdom)

During the 1920s and 1930s, a number of physicians created model premature infant stations in select hospitals, arguing that medicine could successfully treat premature infants, most of whom could be...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A short survey of the energy situation in Iran is given with the aid of some interesting figures. Following remarks on the national and international energy policy, the developments regarding individual energy sources and electricity production are described.

Energy Technology Data Exchange (ETDEWEB)

This paper examines the global impacts of a policy that internalizes the external costs (related to air pollution damage, excluding climate costs) of electricity generation using a combined energy systems and macroeconomic model. Starting point are estimates of the monetary damage costs for SO{sub 2}, NOX, and PM per kWh electricity generated, taking into account the fuel type, sulfur content, removal technology, generation efficiency, and population density. Internalizing these externalities implies that clean and advanced technologies increase their share in global electricity production. Particularly, advanced coal power plants, natural gas combined cycles, natural gas fuel cells, wind and biomass technologies gain significant market shares at the expense of traditional coal- and gas-fired plants. Global carbon dioxide emissions are lowered by 3% to 5%. Sulfur dioxide emissions drop significantly below the already low level. The policy ...

UK PubMed Central (United Kingdom)

BackgroundThe prevalence of tobacco use among individuals with mental illness remains a serious public health concern. Tobacco control has received little attention in community...Full Text Available

UK PubMed Central (United Kingdom)

Policies and regulations in the current health care environment have impacted the manner in which patient data - especially protected health information (PHI) - are handled in the clinical and...Full Text Available

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... (restricted)] 24-53 Cyclicality of Fiscal Policy in Oil-Producing Countries by E. Gurvich & E. Vakulenko & P. Krivenko [Downloadable! (restricted)] 54-75 Russian Energy Efficiency Potential by I. Bashmakov [Downloadable! (restricted)] 76-94 Outlook and ...

Energy Technology Data Exchange (ETDEWEB)

The problems of introducing renewable energy systems into communities having meagre resources are analysed. Topics covered include financial and economic barriers, subsidies and bank policy. It is concluded that without satisfactory financing mechanisms, renewable energies are unlikely to be widespread in the developing world. (UK)

UK PubMed Central (United Kingdom)

Drawing on published tobacco document research and related sources, this article applies Farnsworth and Holden's conceptual framework for the analysis of corporate power and corporate involvement...Full Text Available

CERN Document Server

This paper addresses the problem of fair equilibrium selection in graphical games. Our approach is based on the data structure called the {\\em best response policy}, which was proposed by Kearns et al. \\cite{kls} as a way to represent all Nash equilibria of a graphical game. In \\cite{egg}, it was shown that the best response policy has polynomial size as long as the underlying graph is a path. In this paper, we show that if the underlying graph is a bounded-degree tree and the best response policy has polynomial size then there is an efficient algorithm which constructs a Nash equilibrium that guarantees certain payoffs to all participants. Another attractive solution concept is a Nash equilibrium that maximizes the social welfare. We show that, while exactly computing the latter is infeasible (we prove that solving this problem may involve algebraic numbers of an arbitrarily high degree), there exists an FPTAS for ...

UK PubMed Central (United Kingdom)

Objective: The paper describes the information needs of a state public health agency, compares needs to its library's collection, and evaluates collection development policy accordingly.Methods:...Full Text Available

Science.gov (United States)

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

UK PubMed Central (United Kingdom)

BackgroundThe composition of habitual diets is associated with adverse or protective effects on aspects of health. Consequently, UK public health policy strongly advocates dietary...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The search for alternative fuels and new fuel resources is a top priority for Turkey, as is the case in the majority of countries throughout the world. The fuel policies pursued by governmental or civil authorities are of key importance in the success of alternative fuel use, especially for widespread and efficient use. Following the 1973 petroleum crisis, many users in Turkey, especially in transportation sector, searched for alternative fuels and forms of transportation. Gasoline engines were replaced with diesel engines between the mid-1970s and mid-1980s. In addition, natural gas was introduced to the Turkish market for heating in the early 1990s. Liquid petroleum gas was put into use in the mid-1990s, and bio-diesel was introduced into the market for transportation in 2003. However, after long periods of indifference governmental action, guidance and fuel policies were so weak that they did not make sense. Entrepreneurs and users ...

Science.gov (United States)

... (4) MP club. (5) MP working dogs. (6) Deadly force. (§ 632...security duties. (e) Use MP working dogs in accordance with the provisions...dog. (2) Before releasing a military dog for attack, give a...

International Nuclear Information System (INIS)

Design and procurement of equipment for nuclear power plant took place in late 1970's. A large number of originally installed equipment is obsolete. The manufacturer's do not support their products or have discontinued their production due to technological evolutions or lack of product demand. Lack of spares affects the performance of obsolete equipment and has a negative impact on plant safety and plant production. A proactive approach to address obsolescence is necessary to ensure critical spares are always available when needed. This is an ongoing effort and requires a program to be in place to resolve immediate and longterm issues. A cross-functional team with adequate external exposure is needed to administer the obsolescence program. CANDU utilities and CANDU Owners Group(COG) has taken initiatives to identify lack of equipment spares in the members' plant. The equipment replacement information collected from each ...

Energy Technology Data Exchange (ETDEWEB)

One of the most important goals of the Italian survey, initiated in 1989, was to promote ad hoc policies to reduce radon exposure of the population. In the survey a statistical representative sample of 5000 dwellings was chosen; two six-month measurements were made of the indoor radon concentration, in combination with one six-month measurement of gamma exposure. The results of the radon concentration measurements are reported here: they refer to 80% of the sample. The annual mean value was 81.5Bq.m{sup -3}, which is higher than that reported for other industrialised countries. (author).

International Nuclear Information System (INIS)

The section on environmental impacts covers global environmental concerns and air pollution. Energy systems includes the following: alternative fuels; co-generation; fossil fuels; mechanical thermal storage; fission/fusion; thermal management; electric and hybrid vehicles. The section on renewable energy sources includes biomass, hydrogen, and solar. This volume also contains separate sections for stirling cycles, policy issues, and new technologies for energy utilization. Separate abstracts were prepared for 150 papers of this volume.

Energy Technology Data Exchange (ETDEWEB)

This paper presents a framework for creating a common spatial canvass that can bring together considerations of resource availability, infrastructure reliability, and development costs while strategizing renewable energy investment. We describe the underlying models and methodologies that annotate an investment plan for potential sites over a time-period with costs and constraints which may be imposed on distance from infrastructure, system impact on infrastructure, and policy incentives. The framework is intended as an enabler for visualization, optimization and decision making across diverse dimensions while searching for lucrative investment-plans.

Energy Technology Data Exchange (ETDEWEB)

The fusion breeder is a fusion reactor designed with special blankets to maximize the transmutation by 14 MeV neutrons of uranium-238 to plutonium or thorium to uranium-233 for use as a fuel for fission reactors. Breeding fissile fuels has not been a goal of the US fusion energy program. This paper suggests it is time for a policy change to make the fusion breeder a goal of the US fusion program and the US nuclear energy program. The purpose of this paper is to suggest this policy change be made and tell why it should be made, and to outline specific research and development goals so that the fusion breeder will be developed in time to meet fissile fuel needs.

International Nuclear Information System (INIS)

High-voltage transmission lines can pose an environmental problem, especially in countries where the electricity production is at a distance from the demand location. Planning, construction, and operation of high voltage transmission lines should be conducted within a comprehensive environmental policy, which may include assessment of visual impact, landscape and wildlife protection, and reduction of health risks. This paper reviews the environmental policies and action in planning, construction, and operation as developed by the utilities members of the Union Internationale des Producteurs et Distributeurs d'Energie Electrique (UNIPEDE). The paper also presents a brief outline of the health issues associated with the effects of electromagnetic fields to humans.

Energy Technology Data Exchange (ETDEWEB)

Due mainly to competitive pressures, the practice of offering electric and telephone service under contracts or special tariffs negotiated individually between a utility and its customers has increased in importance in recent years. Moreover, the practice is likely to become still more widespread in the future. This creates questions of public policy that are of interest to regulators and ratepayers alike such as how to supervise the practice, how to encourage utilities to compete while preventing cross-subsidization and anticompetitive behavior, and how the practice will ultimately affect utilities and ratepayers. This report sheds light on the topic by describing approaches that have been taken by the various regulatory commissions and by providing a framework for analyzing such contractors.

Wastenet

... Biogas: The green gas? | EurActiv Biogas has become an attractive alternative source of energy in Europe as the renewable fuel ...Graduate Programme Research Analyst Junior Consultant Training Coordinator Post an EU job Biogas: The green gas? Published: 09 April 2010 |...Updated: 06 July 2010 Biogas has become an attractive alternative source of energy in Europe as the renewable fuel serves several policy priorities, ranging from ... Policy Summary Biogas is a renewable energy source that can be used for heating or electricity production. If compressed, it can ...

British Library Electronic Table of Contents (United Kingdom)

The Maritime Transportation Security Act of 2002 amended the Deepwater Port Act of 1974 to permit the construction of offshore liquefied natural gas (LNG) terminals. Terminals with environmentally destructive open-loop regasification systems were quickly approved in the Gulf of Mexico. This study analyzed the political methods of the George W. Bush administration to determine how it developed offshore LNG. Findings showed that the Bush administration worked closely with the energy industry to promote national energy security and limited the role of certain federal and state agencies through a centralized policy process.

DEFF Research Database (Denmark)

Now, more than ever, there are serious health concerns for obese and overweight children. Schools are the perfect setting for children to learn, and this influence can play an important role in preventing children from becoming obese and overweight. The study concerns the behaviors of Health Promoting School (HPS) according to a broad definition of HPS in World Health Organization (WHO), or dependent on schools own health promoting policies. The purpose of study research is to examine whether promoting physical activity among the children at schools in relation to a school health policy such as Food and Nutrition Policy (FNP). This was determined through the comparisons between the FNP based schools and non policy based schools. The study undertook surveys among school food coordinators in the selected Danish primary schools through a web-based questionnaire. The questions in the survey were more ...

British Library Electronic Table of Contents (United Kingdom)

SummaryThis paper evaluates the status of digitization in 30 Nigerian university libraries with a view to identifying the status, progress, prospects and challenges to digitize library materials and form the basis of providing a roadmap to successful execution of digitization projects. The study assessed the status of digitization of past question papers, theses and dissertations in Nigerian university libraries from May to September 2006 through a self-administered questionnaire, site visits and interviews. It was found that, though there are automation services in those universities, there is no digitization of these materials mentioned in the surveyed institutions. The major obstacles militating against digitizing in the university libraries include lack of funds, lack of appropriate fa...

British Library Electronic Table of Contents (United Kingdom)

BACKGROUND: Calibration by inverse modelling was performed with the MACRO transport and fate model using long-term (>10 years) drainflow and isoproturon (IPU) data from western France. Two lack-of-fit (LOF) indices were used to control the inverse modelling: sum of squares (SS) and an alternative statistic called the vertical-horizontal distance integrator (VHDI), which is designed to account for offsets in observed and predicted arrival times of peak IPU concentration. With these data, SS was artificially inflated because it is limited to comparison of predicted and observed IPU concentrations that are concurrent in time. The LOFs were used along with the index of agreement (d) and the correlation coefficient (r) to ascertain the fit of the calibrated models. RESULTS: Predicted arrival ti...

CERN Document Server

The mean-field pictures based on the standard time-dependent variational approach have widely been used in the study of nonlinear many-boson systems such as the Bose-Hubbard model. The mean-field schemes relevant to Gutzwiller-like trial states $|F>$, number-preserving states $|\\xi >$ and Glauber-like trial states $|Z>$ are compared to evidence the specific properties of such schemes. After deriving the Hamiltonian picture relevant to $|Z>$ from that based on $|F>$, the latter is shown to exhibit a Poisson algebra equipped with a Weyl-Heisenberg subalgebra which preludes to the $|Z>$-based picture. Then states $|Z>$ are shown to be a superposition of $\\cal N$-boson states $|\\xi>$ and the similarities/differences of the $|Z>$-based and $|\\xi>$-based pictures are discussed. Finally, after proving that the simple, symmetric state $|\\xi>$ indeed corresponds to a SU(M) coherent state, a dual version of states $|Z>$ and ...

International Nuclear Information System (INIS)

Particularly high coherence of the x-ray beam is associated, on the ID19 beamline at ESRF, with the small angular size of the source as seen from a point of the sample (0.1-1 #mu#rad). This feature makes the imaging of phase objects extremely simple, by using a 'propagation' technique. The physical principle involved is Fresnel diffraction. Phase imaging is being simultaneously developed as a technique and used as a tool to investigate light natural or artificial materials introducing phase variations across the transmitted x-ray beam. They include polymers, wood, crystals, alloys, composites or ceramics, exhibiting inclusions, holes, cracks, ... . 'Tomographic' three-dimensional reconstruction can be performed with a filtered back-projection algorithm either on the images processed as in attenuation tomography, or on the phase maps retrieved from the images with a reconstruction procedure similar to that used for electron microscopy. The combination of diffraction ...

International Nuclear Information System (INIS)

We describe a camera to record coherent scattering patterns with a soft-x-ray free-electron laser (FEL). The camera consists of a laterally graded multilayer mirror, which reflects the diffraction pattern onto a CCD detector. The mirror acts as a bandpass filter for both the wavelength and the angle, which isolates the desired scattering pattern from nonsample scattering or incoherent emission from the sample. The mirror also solves the particular problem of the extreme intensity of the FEL pulses, which are focused to greater than 10"1"4 W/cm"2. The strong undiffracted pulse passes through a hole in the mirror and propagates onto a beam dump at a distance behind the instrument rather than interacting with a beam stop placed near the CCD. The camera concept is extendable for the full range of the fundamental wavelength of the free electron laser in Hamburg (FLASH) FEL (i.e., between 6 and 60 nm) and into the water window. We have fabricated and tested various ...

International Nuclear Information System (INIS)

There is growing interest in the generation and characterization of femtosecond and subfemtosecond pulses from linac-based free-electron lasers (FELs). In this report, following the method of Ricci and Smith (Phys. Rev. ST Accel. Beams 3, 032801 (2000)), we investigate the measurement of the longitudinal bunch profile of an ultrashort electron bunch produced by these FELs. We show that this method can be applied in a straightforward manner at x-ray FEL facilities such as the Linac Coherent Light Source by slightly adjusting the second bunch compressor followed by running the bunch on an rf zero-crossing phase of the final linac. We find that the linac wakefield strongly perturbs the measurement, and through analysis show that it can be compensated in a simple way. We demonstrate the effectiveness of this method and wakefield compensation through numerical simulations, including effects of coherent synchrotron radiation and longitudinal space ...

International Nuclear Information System (INIS)

The 1.04 GeV-proton elastic scattering from "4"0Ca is studied in the framework of the coherent density fluctuation model (CDFM). The calculations are carried out in the Glauber theoretical scheme with three different charge densities. It is shown that: i) the account of the flucton correlations leads to results considerably different from those obtained in the independent particle Glauber approach (IPGA); ii) in contrast to the case of IPGA the use of a more realistic density improves the agreement of CDPM-results with the experimental data. (orig.).

Science.gov (United States)

The phase space beam analyzer is a measurement instrument that is applied in laser technology to perform analyses of the spatial and angular distribution of rays. We are interested in this instrument as a means to characterize non-coherent light sources. In this context, a closer look at the tolerances of this optical instrument was considered useful. Having a so-called quadrupole lens as a key element, the phase space beam analyzer is a device that features anamorphic optical properties. To describe these anamorphic properties, recurrence was made to a description by extended ray-transfer matrices. This formalism allows for an analysis of the alignment tolerances of the phase space beam analyzer and facilitates a study of the sensitivities of the instrument. The analysis is complemented using numerical ray tracing.

Energy Technology Data Exchange (ETDEWEB)

The relaxation oscillation of the amplified spontaneous radiation pulses emitted from a single-mirror Cu/CuBr laser has been observed for the first time and the experimental characteristics of the relaxation oscillation were obtained. In addition, the spatial and temporal distributions of the light pulse intensity of the amplified spontaneous radiation were also measured and found to be comparatively and uniform. The spatial coherence of the amplified spontaneous radiation was found to be better than that of the laser with the same lasant.

Energy Technology Data Exchange (ETDEWEB)

Recent experimental results indicate a dominance of fundamental NN..-->..NN..pi.. processes in near-threshold nuclear pion production. Such two-nucleon processes are revealed in part by distinct polarization effects characterizing both weak (ground state) and strong, highly selective, maximal J coupling transitions for the (p,..pi../sup -/) reaction. For (p,..pi../sup +/), where several NN processes can contribute coherently, analyzing power data suggest a means of distinguishing the contributions from different fundamental NN..-->..NN..pi.. isospin channels.

CERN Document Server

Constrained quantum dynamics is used to propose a nonlinear dynamical equation for pure states of a generalized coarse-grained system. The relevant constraint is given either by the generalized purity or by the generalized invariant fluctuation, and the coarse-grained pure states correspond to the generalized coherent i.e. generalized nonentangled states. Open system model of the coarse-graining is discussed. It is shown that in this model and in the weak coupling limit the constrained dynamical equations coincide with an equation for pointer states, based on Hilbert-Schmidt distance, that was previously suggested in the context of the decoherence theory.

Energy Technology Data Exchange (ETDEWEB)

In the early days of Moessbauer spectroscopy, it was demonstrated that coherent scattering of photons emitted by a Moessbauer source can be observed. In spite of the fact that scattering experiments could give information not accessible by the absorption method, they are not widely used. The reasons for this are, on the one hand, experimental difficulties, and on the other hand, the form of the samples, which should be large single crystals in most cases. In this work, we present a Moessbauer diffraction measurement on polycrystalline bcc iron where these problems have been overcome. We demonstrate that using the kinematical theory of gamma-ray diffraction, useful information on the relative orientation of the crystallographic axis to the hyperfine field directions can be subtracted. (orig.)

Energy Technology Data Exchange (ETDEWEB)

High-T/sub c/ superconductivity is due to the action of two mechanisms: (1) plasmon mechanism, i.e., exchange of two-dimensional (2-D) plasmons and (2) strong electron--phonon coupling. The low dimensionality and the small value of the carrier concentration make the plasmon mechanism favorable. The small value of the coherence length leads to a unique opportunity to observe a multigap structure. The proximity effect can be used in order to increase T/sub c/ of A-15 compounds.