Search

A discussion of health equity should be intricately examined in policy and practice discourse about the healthcare industry. This article addresses health equity with strategies to institutionalize it through policy implementation. This discourse is relevant to social work because social workers are charged with elucidating conditions that are maniacal and disadvantageous to racial groups, undocumented workers, immigrants and women. Social workers engaged in policy practice should consider how these stakeholders are excluded from health equity, because of the lack of transformative policy implementation that addresses industry practices that encourage disparity and maintain equity. This article hopes to provide a helpful view of health equity.

The self-focusing characteristic of 355 nm, 3.3 ns pulses propagating through phosphate glass samples is found to significantly change during repeated exposure. The results indicate this change is related to the formation of color centers in the material as well as the generation of a transient defect population during exposure to the laser pulses. A model is used to fit the experimental data and obtain an estimated range of values for the modified linear and nonlinear indices of refraction.

Pitch button blocking (PBB), involving attaching small pitch buttons between the back of a thin workpiece (i.e., optic) and a blocking plate, enables noncompliant convergent polishing in which the workpiece stiffness and block interface strength are maintained. This process has been optimized, and practical design criteria (number, size, and spacing of pitch buttons) have been determined both experimentally and theoretically using a thermoelastic model. The optimized PBB process has been successfully implemented on 100-265 mm sized workpieces with aspect ratios up to 45, resulting in maximum peak-to-valley heights of <|0.1| μm after blocking and polishing.

The light emission produced near the surface of fused silica following laser-induced breakdown on the exit surface was spatially and spectrally resolved. This signal is in part generated by ejected particles while traveling outside the hot ionized region. The thermal emission produced by the particles can be separated from the plasma emission near the surface and its spectral characteristics provide information on the temperature of the particles after ejection from the surface. Assuming the emission is thermal in origin, data suggest an initial average temperature on the order of at least 0.5 eV.

The transient changes in the optical properties of bulk DKDP material arising from its exposure to high temperatures and pressures associated with localized laser energy deposition are investigated. Two methods for initiation of laser-induced breakdown are used, intrinsic, involving relatively large energy deposition brought about by focusing of the laser beam to high intensities, and extrinsic, arising from more localized deposition due to the presence of pre-existing absorbing damage initiating defects. Each method leads to a very different volume of material being affected, which provides for different material thermal relaxation times to help better understand the processes involved.

Surface laser damage limits the lifetime of optics for systems guiding high fluence pulses, particularly damage in silica optics used for inertial confinement fusion-class lasers (nanosecond-scale high energy pulses at 355 nm/3.5 eV). The density of damage precursors at low fluence has been measured using large beams (1-3 cm); higher fluences cannot be measured easily since the high density of resulting damage initiation sites results in clustering. We developed automated experiments and analysis that allow us to damage test thousands of sites with small beams (10-30 µm), and automatically image the test sites to determine if laser damage occurred. We developed an analysis method that provides a rigorous connection between these small beam damage test results of damage probability versus laser pulse energy and the large beam damage results of damage precursor densities versus fluence. We find that for uncoated and coated fused silica samples, the distribution of precursors nearly flattens at very high fluences, up to 150 J/cm2, providing important constraints on the physical distribution and nature of these precursors.

Growing laser damage sites on multilayer high-reflector coatings can limit mirror performance. One of the strategies to improve laser damage resistance is to replace the growing damage sites with predesigned benign mitigation structures. By mitigating the weakest site on the optic, the large-aperture mirror will have a laser resistance comparable to the intrinsic value of the multilayer coating. To determine the optimal mitigation geometry, the finite-difference time-domain method was used to quantify the electric-field intensification within the multilayer, at the presence of different conical pits. We find that the field intensification induced by the mitigation pit is strongly dependent on the polarization and the angle of incidence (AOI) of the incoming wave. Therefore, the optimal mitigation conical pit geometry is application specific. Furthermore, our simulation also illustrates an alternative means to achieve an optimal mitigation structure by matching the cone angle of the structure with the AOI of the incoming wave, except for the p-polarized wave at a range of incident angles between 30° and 45°.

The problematic behaviors of teenagers and the subsequent negative consequences are extensive and well documented: unwanted pregnancy, substance abuse, violent behavior, depression, and social and psychological consequences of unemployment. In this article, the authors review an approach that uses a cooperative learning, empirically based intervention that employs peers as teachers. This intervention of choice is Teams-Games-Tournaments (TGT), a paradigm backed by five decades of empirical support. The application of TGT in preventive health programs incorporates elements in common with other prevention programs that are based on a public health orientation and constitute the essential components of health education, that is, skills training and practice in applying skills. The TGT intervention supports the idea that children and adolescents from various socioeconomic classes, between the ages of 8 and 18 and in classrooms or groups ranging in size from 4 to 17 members, can work together for one another. TGT has been applied successfully in such diverse areas as adolescent development, sexuality education, psychoactive substance abuse education, anger control, coping with depression and suicide, nutrition, comprehensive employment preparation, and family intervention. This article reviews the extensive research on TGT using examples of successful projects in substance abuse, violence, and nutrition. Issues are raised that relate to the implementation of preventive health strategies for adolescents, including cognitive aspects, social and family networks, and intervention components.

The optical damage threshold of indentation-induced flaws on fused silica surfaces was explored. Mechanical flaws were characterized by laser damage testing, as well as by optical, secondary electron, and photoluminescence microscopy. Localized polishing, chemical leaching, and the control of indentation morphology were used to isolate the structural features that limit optical damage. A thin defect layer on fracture surfaces, including those smaller than the wavelength of visible light, was found to be the dominant source of laser damage initiation during illumination with 355 nm, 3 ns laser pulses. Little evidence was found that either displaced or densified material or fluence intensification plays a significant role in optical damage at fluences >35 J/cm(2). Elimination of the defect layer was shown to increase the overall damage performance of fused silica optics.

Laser-induced damage at near operational laser excitation conditions can limit the performance of potassium dihydrogen phosphate (KH(2)PO(4), or KDP) and its deuterated analog (DKDP) which are currently the only nonlinear optical materials suitable for use in large-aperture laser systems. This process has been attributed to pre-existing damage precursors that were incorporated or formed during growth that have not yet been identified. In this work, we present a novel experimental approach to probe the electronic structure of the damage precursors. The results are modeled assuming a multi-level electronic structure that includes a bottleneck for 532 nm excitation. This model reproduces our experimental observations as well as other well-documented behaviors of laser damage in KDP crystals. Comparison of the electronic structure of known defects in KDP with this model allows for identification of a specific class that we postulate may be the constituent defects in the damage precursors. The experimental results also provide evidence regarding the physical parameters affecting the ability of individual damage precursors to initiate damage, such as their size and defect density; these parameters were found to vary significantly between KDP materials that exhibit different damage performance characteristics.

We report on the material response during the cooling phase in bulk fused silica following localized energy deposition via laser-induced breakdown.We use a time-resolved microscope system to acquire images of the region of energy deposition at delay times covering the entire timeline of events. In addition, this system is configured to perform pump-and-probe damage testing measurements to investigate the evolution of the transient absorption of the modified material. The main features of a damage site are established at approximately 30 ns after the pump pulse, i.e. cracks reach their final size within this time frame. The results reveal that the cracks and melted core exhibit a transient absorption up until about 300 ns and 200 micros delay times, respectively, and suggest that the melted region returns to solid phase at approximately 70 ms delay., ((c) 2010 Optical Society of America.)

The initiation of laser damage within optical coatings can be better understood by electric-field modeling of coating defects. The result of this modeling shows that light intensification as large as 24x can occur owing to these coating defects. Light intensification tends to increase with inclusion diameter. Defects irradiated over a range of incident angles from 0 to 60 deg tend to have a higher light intensification at a 45 deg incidence. Irradiation wavelength has a significant effect on light intensification within the defect and the multilayer. Finally, shallow, or in the case of 45 deg irradiation, deeply embedded inclusions tend to have the highest light intensification.

Optical breakdown by femtosecond and nanosecond laser pulses in transparent dielectrics produces an ionized region of dense plasma confined within the bulk of the material. This ionized region is responsible for broadband radiation that accompanies the breakdown process. Spectroscopic measurements of the accompanying light have been used to show that, depending on the laser parameters, the spectra may originate from plasma-induced second-harmonic generation, supercontinuum generation, or thermal emission by the plasma. By monitoring the emission from the ionized region, one can ascertain the predominant breakdown mechanism and the morphology of the damage region.

No statistician, social scientist or tarot card reader is needed to attest that the gap between the rich and poor in America is increasing. Further, most Americans don't care that much about it. There are also more rich people today living in the U.S. and there are more people living in poverty. Between 2000 and 2002, the number of Americans living in poverty increased by nearly 3 million to 34.6 million. Of these, 12% (or about one half a million persons) are living extreme poverty and many are children, with 16.7% likely to be poor (National Association of Social Workers, 2003).

Laser-induced damage in wide band-gap optical materials is the result of material modifications arising from extreme conditions occurring during this process. The material absorbs energy from the laser pulse and produces an ionized region that gives rise to broadband emission. By performing a time-resolved investigation of this emission, we demonstrate both that it is blackbody in nature and that it provides the first direct measurement of the localized temperature of the material during and following laser damage initiation for various optical materials. For excitation using nanosecond laser pulses, the plasma, when confined in the bulk, is in thermal equilibrium with the lattice. These results allow for a detailed characterization of temperature, pressure, and electron densities occurring during laser-induced damage.

Laser-induced pinpoint bulk damage of deuterated potassium dihydrogen phosphate at 351 nm is shown to depend on the propagation direction relative to the crystallographic axes and on growth temperature in addition to the previously reported dependence on continuous filtration. Pulse-length scaling is also consistent with earlier reports. The leading hypothesis for the cause of pinpoint damage is absorbing nanoparticle impurities, and our results are consistent with but not conclusive for that model. Advances in technology have led to greatly improved damage resistance.

Ablation characteristics of ultrashort laser pulses were investigated for pulse durations in the range of 130 fs-10 ps. Tissue samples used in the study were dental hard tissue (dentin) and water. We observed differences in ablation crater morphology for craters generated with pulse durations in the 130 fs-1 ps and the 5 ps-10 ps range. For the water experiment, the surface ablation and subsequent propagation of stress waves were monitored using Mach-Zehnder interferometry. For 130 fs-1 ps, energy is deposited on the surface while for longer pulses the beam penetrates into the sample. Both studies indicate that a transition occurs between 1 and 5 ps.

Public policy affects health and social services organizations. Senior management has a responsibility to prevent inappropriate demands of stakeholders from predominating and to influence the outcome of public policy to the benefit of their organization through the strategic issues management process. This article presents a public policy issue life cycle model, life-cycle stages and suggested strategies, paths issues can take in the life cycle, and factors that affect issue paths. An understanding of these dynamics can aid senior managers in shaping and changing public policy issues and lessening external environment threats to their organization.

Light intensity modulations caused by opaque obstacles (e.g., dust) on silica lenses in high-power lasers often enhance the potential for laser-induced damage. To study this effect, particles (10-250 mum) with various shapes were sputter deposited on the input surface and irradiated with a 3-ns laser beam at 355 nm. Although a clean silica surface damages at fluences above 15 J/cm(2), a surface contaminated with particles can damage below 11.5 J/cm(2). A pattern that conforms to the shape of the input surface particle is printed on the output surface. Repetitive illumination resulted in catastrophic drilling of the optic. The damage pattern correlated with an interference image of the particle before irradiation. The image shows that the incident beam undergoes phase (and amplitude) modulations after it passes around the particle. We modeled the experiments by calculating the light intensity distribution behind an obscuration by use of Fresnel diffraction theory. The comparison between calculated light intensity distribution and the output surface damage pattern showed good agreement. The model was then used to predict the increased damage vulnerability that results from intensity modulations as a function of particle size, shape, and lens thickness. The predictions provide the basis for optics cleanliness specifications on the National Ignition Facility to reduce the likelihood of optical damage.

In light of new welfare reforms, it is essential that public welfare workers move individuals from welfare to work in an expedient fashion. Client alcohol and/or drug use/abuse is one barrier that may inhibit this process. The following study (N = 93) administered both the Hudson Index of Alcohol Involvement, the Hudson Index of Drug Involvement (rapid assessment instruments) and the Miller Substance Abuse Subtly Screening Inventory (SASSI) to public welfare and Child Protection system clients. Results indicated that the two rapid assessment measures strongly correlated with the advanced, commonly used SASSI measure. It is suggested that public welfare workers should institute these rapid assessment instruments at intake to screen clients for alcohol and drug use/abuse. When indicated, the client could then be referred to the appropriate agency for further assessment and treatment, to better prepare them for employment as mandated by new welfare reforms. The rapid assessment instruments were found to be shorter than the SASSI, easily administered, and able to detect alcohol and/or drug use/abuse effectively and efficiently in these populations.

The azimuthal dependence of third-order and cascaded second-order nonlinear coupling was used to measure the relative contributions of each to direct third-harmonic generation in beta-barium borate. This permitted the measurement of the values of tensor elements chi(3)(10) , chi(3)(11) , and chi(3)(16) relative to the known chi(2)(ij) . Finally, conversion efficiencies to 3 omega of up to 6% were achieved with a femtosecond chirped-pulse amplification laser with 200 GW/cm(2) in collimated beams.

An iterative algorithm for constructing fully continuous phase screens for tailoring far-field intensity profiles is presented. The algorithm is robust, stable, and, if run properly, maintains the continuous nature of the phase throughout the iterative process. The iterative procedure is applied to generate continuous phase screens to produce a 12th-power super-Gaussian far-field intensity profile.

We have constructed an optical parametric oscillator to generate 75-ps near-transform-limited pulses with wavelengths tunable about 1.053 µm for use in pump-probe studies of self-focusing. The singly resonant oscillator uses a Brewster-cut LiB(3)O(5) crystal that is oriented for type-II phase matching and synchronously pumped by the amplified and frequency-tripled pulse trains from a mode-locked and Q-switched Nd:YLP laser. An intracavity Pockels cell is used to switch out single 0.5-MW pulses at rates of 1 to 10 Hz. The design, construction, and performance of the oscillator are discussed. Measured performance is compared with design predictions and with detailed numerical simulations.

We demonstrate accurate modeling of ultrawide-angle beam propagation in homogeneous media by Lanczos orthogonalization for acceptable longitudinal step sizes. Accuracy is determined by comparison with solutions to the Helmholtz equation obtained by a band-limited Fourier series method.

The numerical scheme for solving the Helmholtz equation, based on the Lanczos orthogonalization scheme, is generalized so that it can be applied to media with space-dependent absorption or gain profiles.

Employing a time-dependent model with counterpropagating beams and saturable gain, we calculate the degree of coherence for a range of x-ray lasers. From these results we infer a scaling law that can be used to estimate the degree of coherence of a general class of x-ray lasers.

This article builds on a previous publication and presents additional information on how cost effectiveness analysis may be used by policy and decision-makers in human service organizations (HSO's). It presents a brief history of the use of cost effectiveness analysis to demonstrate its efficacy in assisting policy makers in a variety of fields. It then comparatively describes two of the best known cost effective methods--cost benefit analysis (CBA) and cost effective analysis (CEA), and argues that the latter is the more appropriate method to be used to effect policy decisions in HSO's. The discussion centres around refining the limitations of the CEA method and proposes a simple model for use in this regard. Recommendations and implications are directed toward managers, administrators and decision-makers of HSO's. Finally, the article is attempting to fill a distinct void in the literature in this field and also suggests the use of more meaningful policy formulation and analyses methods in HSO's.

An accurate numerical method is described for solving the Helmholtz equation for a general class of optical fibers. The method yields detailed information about the spatial and angular properties of the propagating beam as well as the modal propagation constants for the fiber. The method is applied to a practical graded-index fiber under the assumptions of both coherent and incoherent illumination. A spectral analysis of the calculated field shows that leaky modes are lost and steady-state propagating conditions are established over a propagation distance of a fraction of a meter.

We describe a spectral method for solving the paraxial wave equation in cylindrical geometry that is based on expansion of the exponential evolution operator in a Taylor series and use of fast Fourier transforms to evaluate derivatives. A fourth-order expansion gives excellent agreement with a two-transverse-dimensional split-operator calculation at a fraction of the cost in computation time per z step and at a considerable savings in storage.

A new computational method for unloaded optical resonators is developed based on the discrete Fourier analysis of information generated by repeated iterations of the optical field corresponding to transits between reflectors. The method is a straightforward extension of the propagating beam method developed earlier for optical fibers for extracting modal properties from numerical solutions to the paraxial scalar wave equation. The method requires computation of a field correlation function, whose Fourier transform reveals the eigenmodes as resonant peaks. Analysis of the location and breadth of these peaks determines the resonator eigenvalues. When the eigenvalues are known, additional discrete Fourier transforms of the field are used to generate the mode eigenfunctions. This new method makes possible the unambiguous identification and accurate characterization of the entire spectrum of transverse resonator modes.

This article describes how decision-makers may use a relatively simple cost-effectiveness analysis (CEA) method in policy formulation in human service organizations. The main contention of this article is that decision-makers need to know how to better effect policy decisions based on quantitative data. CEA is a decision-making tool which has been used sparingly in human service organizations, even though it is considered to be extremely useful in developing rational, cost-effective programs for the future. The paper describes the CEA model in a sequential step-by-step fashion and discusses its analytic processes and how it measures the costs and effects of human service programs. The conclusions and recommendations are targeted at decision-makers in human service organizations and stress the importance of obtaining accurate, reliable and useful cost-effectiveness data.

The propagating beam method generates solutions for the electric field in a graded-index optical fiber that emphasize beam characteristics rather than modal properties. Through Fourier analysis with respect to axial distance z, these solutions can be made to yield such mode properties as the propagation constants beta(n), the mode group delays partial differentialbeta(n)/ partial differentialomega, and the mode eigenfunctions. The propagating beam method has been applied to a detailed study of two index profiles with finite thickness cladding: an axisymmetric power-law (alpha = 1.85) profile both without and with an on-axis dip. In nine successive computer runs, eighty-five and eighty-four bound or guided modes were excited and characterized for the two respective profiles. The mode group delays near cutoff for both profiles show large deviation from those derived with the WKB method. In addition, sets of almost degenerate modes near cutoff show large differences in group delay. Modes with low azimuthal quantum number are strongly perturbed by the central dip. It is found that rms pulse dispersion is quite sensitive to the inclusion or exclusion of modes near cutoff, but that frequency response bandwidth is not. This leads to the conclusion that fiber bandwidth cannot be accurately inferred from rms pulse dispersion and may explain why broadband multimode fibers exist dispite strong perturbation of the modes near cutoff.

The theory of optical fibers has been concerned mainly with propagation in lossless waveguides. Although real fibers are composed of core materials with extremely small absorption coefficients, they may have claddings and jackets with substantially higher losses. These components can in turn selectively attenuate certain higher-order guided modes. The propagating beam method utilizes configuration space solutions to a scalar wave equation to generate the mode propagation constants and eigenfunctions for a general class of weakly guiding fibers. This method has now been generalized to treat fibers with absorbing components such as claddings and jackets. It is now possible to compute with this generalized method both the mode attenuation coefficients and mode eigenfunctions for such fibers. Results are given for planar and circularly symmetric waveguides with lossy claddings and jackets.

The propagating beam method utilizes discrete Fourier transforms for generating configuration-space solutions to optical waveguide problems without reference to modes. The propagating beam method can also give a complete description of the field in terms of modes by a Fourier analysis with respect to axial distance of the computed fields. Earlier work dealt with the accurate determination of mode propagation constants and group delays. In this paper the method is extended to the computation of mode eigenfunctions. The method is efficient, allowing generation of a large number of eigenfunctions from a single propagation run. Computations for parabolic-index profiles show excellent agreement between analytic and numerically generated eigenfunctions.

The current federal narcotic detoxification policy, limiting such treatment to 21 d, is analyzed with respect to its impact on the success rate for complete withdrawal. Data are drawn from an historical review of American Medical Association statements on narcotic addiction and a review of empirical data on short- and long-term detoxification. The 3-week limit is shown to interfere with achieving successful detoxification rates, although it continues to guide federal detoxification policy. Empirical evidence supports long-term detoxification that recognizes other factors as also having a therapeutic effect. It is time to revise the current federal policy to more accurately reflect the progress made in long-term care.

Methods are developed for extracting from a numerical propagating-beam solution of a scalar wave equation the information necessary to compute the impulse-response function and the pulse dispersion for a multimode graded-index fiber. It is shown that the scalar Helmholtz equation and the parabolic wave equation have the same set of eigenfunctions in common and that the eigenvalues for the two equations are simply related. Thus one can work exclusively with the simpler parabolic equation. Both the mode eigenvalues (propagation constants) and mode weights, which are necessary for determining the impulse response, can be obtained with high accuracy from a numerical Fourier transform of the complex field-correlation function by the use of digital-filtering techniques. It is shown how a solution obtained in the absence of profile dispersion can be simply corrected for the presence of profile dispersion. In an illustrative example a gradedindex fiber with a central dip in its profile is considered.

The analogy between optics and quantum mechanics is exploited by considering a 2-D quantum system whose Schroedinger equation is closely related to the wave equation for light propagation in an optical fiber. From this viewpoint, Marcatili's condition for minimal-dispersion-refractive-index profiles, and the Olshansky- Keck formula for rms pulse spreading in an alpha-profile fiber may be derived without recourse to the WKB approximation. Besides affording physical insight into these results, the present approach points out a possible limitation in their application to real fibers.