Anisotropic surface melting in lyotropic cubic crystals: part 2: facet-by-facet melting at Ia3d/vapor interfaces.

From experiments with metal crystals, in the vicinity of their crystal/liquid/vapor triple points, it is known that melting of crystals starts on their surfaces and is anisotropic. Recently, we have shown that anisotropic surface melting occurs also in lyotropic systems. In our previous paper (Eur. Phys. J. E 19, 223 (2006)), we have focused on the case of poor faceting at the Pn3m/L1 interface in C12EO2/water binary mixtures. There anisotropic melting occurs in the vicinity of a Pn3m/L3/L1 triple point. In the present paper, we focus on the opposite case of a rich devil's-staircase-type faceting at Ia3d/vapor interfaces in monoolein/water and phytantriol/water mixtures. We show that anisotropic surface melting takes place in these systems in a narrow humidity range close to the Ia3d-L2 transition. As whole (hkl) sets of facets disappear one after another when the transition is approached, surface melting occurs in a facet-by-facet type.

Anisotropic surface melting in lyotropic cubic crystals. Part 1: Pn3m/L1 interface, poor faceting.

From experiments with ice or metal crystals, in the vicinity of their crystal/liquid/vapor triple points, it is known that melting of crystals starts on their surfaces and is anisotropic. It is shown here by direct observations under an optical microscope that this anisotropic surface melting phenomenon occurs also in lyotropic systems. In the case of C12EO2/water mixture, it takes place in the vicinity of the peritectic Pn3m/L3/L1 triple point. Above the peritectic triple point, where the Pn3m and L1 phases coexist in the bulk, the surface of a Pn3m-in-L1 crystal is composed of (111)-type facets surrounded by rough surfaces. The angular junction suggests that rough surfaces are wet by a L3-like layer while facets stay "dry". This is analogous to the pre-melting at rough surfaces in solid crystals. Upon cooling below the peritectic triple point, where L3 and L1 phases coexist in the bulk, a thick layer of the L3 phase grows from the pre-melted, rough Pn3m/L1 interface. Simultaneously, facets stay dry and their radius decreases. In this tri-phasic configuration, stable in a narrow temperature range, the L3/L1 and L3/Pn3m interfaces have shapes of constant mean curvature surfaces having common borders: edges of facets.

Correlated strength in the nuclear spectral function.

We have carried out an (e,e'p) experiment at high momentum transfer and in parallel kinematics to measure the strength of the nuclear spectral function S(k,E) at high nucleon momenta k and large removal energies E. This strength is related to the presence of short-range and tensor correlations, and was known hitherto only indirectly and with considerable uncertainty from the lack of strength in the independent-particle region. This experiment locates by direct measurement the correlated strength predicted by theory.

Soft fermi surfaces and breakdown of Fermi-liquid behavior.

Electron-electron interactions can induce Fermi surface deformations which break the point-group symmetry of the lattice structure of the system. In the vicinity of such a "Pomeranchuk instability" the Fermi surface is easily deformed by anisotropic perturbations, and exhibits enhanced collective fluctuations. We show that critical Fermi surface fluctuations near a d-wave Pomeranchuk instability in two dimensions lead to large anisotropic decay rates for single-particle excitations, which destroy Fermi-liquid behavior over the whole surface except at the Brillouin zone diagonal.

Measurement of the electric form factor of the neutron through d-->(e-->,e(')n)p at Q2 = 0.5 (GeV/c)(2).

We report the first measurement using a solid polarized target of the neutron electric form factor G(n)(E) via d-->(e-->,e(')n)p. G(n)(E) was determined from the beam-target asymmetry in the scattering of longitudinally polarized electrons from polarized deuterated ammonia ( 15ND3). The measurement was performed in Hall C at Thomas Jefferson National Accelerator Facility in quasifree kinematics with the target polarization perpendicular to the momentum transfer. The electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle segmented detector. We find G(n)(E) = 0.04632+/-0.00616(stat)+/-0.00341(syst) at Q2 = 0.495 (GeV/c)(2).

Measurement of the recoil polarization in the p(e-->, e'p-->)pi(0) reaction at the Delta(1232) resonance.

The recoil proton polarization has been measured in the p(e-->,e'p-->)pi(0) reaction in parallel kinematics around W = 1232 MeV, Q2 = 0.121 (GeV/c)2, and epsilon = 0.718 using the polarized cw electron beam of the Mainz Microtron. All three proton polarization components, Px/P(e) = (-11.4+/-1.3+/-1.4)%, P(y) = (-43.1+/-1.3+/-2.2)%, and P(z)/P(e) = (56.2+/-1.5+/-2.6)%, could be measured simultaneously. The Coulomb quadrupole to magnetic dipole ratio, CMR = (-6.4+/-0.7(stat)+/-0.8(syst))%, was determined from Px in the framework of the Mainz Unitary Isobar Model. The consistency among the reduced polarizations and the extraction of the ratio of longitudinal-to-transverse response is discussed.

Devil's staircase-type faceting of a cubic lyotropic liquid crystal

The faceting of monocrystals of the lyotropic cubic liquid crystals in equilibrium with a humid atmosphere is observed. Experiments reveal the presence of more than 60 different types of facets on the surface of a spherical crystal of radius R = 1 mm. The devil's staircase type of faceting has been predicted theoretically when the interaction between steps on the crystal surface is repulsive.

The five-factor model of personality: findings in males with spinal cord injury.

The purpose of this study was to identify common personality traits in males with traumatic spinal cord injury (SCI). One hundred and five participants with SCI completed the NEO Personality Inventory (NEO-PI). The participants averaged 41.1 years of age and 17.9 years since injury onset. Compared with the NEO-PI normative sample, the SCI sample scored significantly lower on the Conscientiousness factor and the Activity and Assertiveness facet scales. They scored significantly higher on the Excitement-Seeking scale. These results suggest that males with SCI are less determined, have lower energy levels, are socially retiring, and that they tend to seek stimulation. These findings may reflect the contribution of both preinjury personality traits and adaptation to the limitations imposed by SCI.

Management of impairment, disability, and handicap due to multiple sclerosis.

In this article, we update management measures for patients with multiple sclerosis (MS) that can improve or prevent impairment, disability, and handicap and include those factors that a primary-care physician can implement or facilitate. The medical literature since 1989 was reviewed. Although new drug trials hold promise to decrease impairment from MS, well-coordinated interdisciplinary care to minimize disability and handicap most profoundly affect the quality of life for patients with MS. MS is usually not severely disabling, and appropriately timed intervention can prevent secondary impairment and reduce disability and handicap. Pharmacologic, physical, and psychosocial issues--ranging from spasticity, pain, weakness, and tremor to neurogenic bowel management and sexuality--are addressed. General wellness measures remain important. The influence of the Americans With Disabilities Act is discussed, and specific adaptive equipment and social resources are outlined. The ultimate goals of management of patients with MS are functional independence and efficient use of medical and community resources: a focus on "ability" rather than "disability." Although impairment can limit function, wellness and adjustment have no boundaries.

Quality of life after surgical treatment of cancer of the larynx.

The purpose of the study was to assess the quality of life of patients after surgical treatment for cancer of the larynx. Three groups of patients were identified according to surgical treatment: total laryngectomy, 111 patients; near-total laryngectomy, 38 patients; and partial laryngectomy, 23 patients. The impact of successful surgical treatment on their life roles was analyzed in terms of work, activities, familial and spousal relationships, sexuality, and psychologic features such as stress and anxiety. Two questionnaires were used; the Psychosocial Adjustment to Illness Scale (PAIS) and the Mayo Clinic Postlaryngectomy Questionnaire. With the PAIS questionnaire, no difference was found in role adjustment between the total laryngectomy and near-total laryngectomy groups, with one exception. In the work domain, the total laryngectomy patients who were working had better adjustment than the near-total laryngectomy patients. The overall adjustment of both groups was less favorable than that of a comparison group of patients with nonlaryngeal cancer. The patients who had the classic conservation operations adjusted in all domains more favorably than the patients with permanent tracheostomas. The partial operation patients adjusted better than the nonlaryngeal cancer patients. We conclude that the stoma has a negative impact on adjustment postoperatively and that it may have a more serious impact on life adjustment than voice alteration. Further investigation and standardization of measurement tools are needed.

Clinical engineering program productivity and measurements.

The health care delivery system is undergoing evolutionary changes that are also affecting Clinical Engineering. The integration of engineering and the life sciences created an industry whose "product" must be quality patient care. The utilization of technologies in the clinical environment is perpetually growing, and has created a need for professional technical management. The present changing environment requires Clinical Engineers to become effective leaders and efficient managers. The efficient consumption of an organization's resources is dependent on its managers' abilities to assess and optimize their operations under dynamic conditions. This paper describes some means for monitoring the clinical engineering department "output" and for measuring and reporting the relative changes in output, thus enhancing progress toward achievement of established goals. The tools and techniques offered here are not an end in themselves, but are rather a part of the process of maximizing productivity with a commitment to program output quality.

Substance abuse policies in rehabilitation medicine departments.

A 27-item substance abuse questionnaire covering attitudes, beliefs, and policies was sent to the directors or other representatives of the 68 physical medicine and rehabilitation training programs in the United States. Anonymity of the respondents was guaranteed. Respondents representing 52 programs (76%) from 20 states participated. Almost all respondents were physicians; most were rehabilitation unit directors, directors of residency training, or department chairpersons. The average size of the rehabilitation units was 46 beds. Four important findings are emphasized. First, 73% of respondents were concerned about alcohol or drug (A/D) problems in their patients, but only 52% supported routine A/D screening for all patients. Importantly, only 25% routinely screened all patients. Second, 90% supported guidelines prohibiting A/D use in the rehabilitation unit, but only 65% had a prohibition policy and only 45% had written guidelines. More than 50% of the respondents stated that there were appropriate reasons for ordering alcohol for an inpatient. Third, 92% supported immediate intervention for inpatients found to have A/D problems, but only 55% routinely provided access to drug counselors. Fourth, 75% were in favor of drug abuse education for patients and staff, but only 29% provided education to patients and 22% to staff. The results suggest that the problems of A/D abuse in the physically disabled have yet to be adequately recognized and addressed by workers in rehabilitation medicine.

Effect of videotape replay on the quality and accuracy of student self-evaluation.

This study was designed to determine the effect of videotape replay on the quality and accuracy of student self-evaluation. Thirty-two junior physical therapy students were asked to perform a clinical skill and to assess their performances using the Performance Evaluation Form (PEF) designed for this study. The students in the Experimental Group assessed their performances after viewing a videotape replay. Students in the Control Group assessed their performances without viewing videotape replays. Faculty judges used the PEF to rate each student's performance. The instructor and student ratings were compared to determine the accuracy of student ratings. In addition, two faculty judges used a scale designed for this study to rate the degree of quality of each student's self-evaluation. No significant differences were found between the Experimental Group and the Control Group on either of the variables tested. The data gathered in this study indicated that videotape replay lacks value in enhancing self-assessment when evaluation immediately follows the performance of a skill. Further study is indicated.