Interplay between quantum shells and orientation in quasifission.

The quasifission mechanism hinders fusion in heavy systems through breakup within zeptoseconds into two fragments with partial mass equilibration. Its dependence on the structure of both the collision partners and the final fragments is a key question. Our original approach is to combine an experimental measurement of the fragments' mass-angle correlations in (40)Ca+(238)U with microscopic quantum calculations. We demonstrate an unexpected interplay between the orientation of the prolate deformed (238)U with quantum shell effects in the fragments. In particular, calculations show that only collisions with the tip of (238)U produce quasifission fragments in the magic Z=82 region, while collisions with the side are the only ones that may result in fusion.

Predominant time scales in fission processes in reactions of S, Ti and Ni with W: zeptosecond versus attosecond.

The inhibition of fusion by quasifission is crucial in limiting the formation of superheavy elements in collisions of heavy nuclei. Time scales of ∼10(-18) s inferred for fissionlike events from recent crystal blocking measurements were interpreted to show either that quasifission itself is slower than previously believed, or that the fraction of slow fusion-fission is higher than expected. New measurements of mass-angle distributions for (48)Ti and (64)Ni bombarding W targets show that in these reactions quasifission is the dominant process, typically occurring before the system formed after contact has made a single rotation, corresponding to time scales of ≤10(-20) s.

A multicentre evaluation of the Elecsys® HIV Duo assay.

BACKGROUND: Fourth generation HIV assays, which detect both HIV p24 antigen and HIV antibodies are widely used in HIV screening. The combination of markers enables the fourth generation assays to shorten the window of detection, which is important in real-world testing scenarios. The Elecsys® HIV Duo assay is a fourth generation assay, which provides an overall result based on both the detection of the p24 antigen and HIV antibodies, and lists the sub-results for the antibody and antigen units. OBJECTIVES AND STUDY DESIGN: The performance of the Elecsys® HIV Duo assay was assessed at five international centres and compared with other available fourth generation assays. RESULTS: The specificity of the Elecsys® HIV Duo assay in 13,328 blood donor samples was 99.87% (95% confidence interval [CI] 99.80-99.93) and was 100% (95% CI 99.63-100) in 1000 routine diagnostic samples. Sensitivity was assessed in 139 seroconversion panels; the Elecsys® HIV Duo assay detected a greater number of positive samples/number of bleeds compared with other assays investigated. An individual analysis of those seroconversion panels also shows that the Elecsys® HIV Duo assay compared to other fourth generation assays detected HIV up to 2 days earlier than other assays. The Elecsys® HIV Duo assay also detected 125/130 'early seroconversion' samples assessed, which was greater than the number detected with comparator fourth generation assays. CONCLUSION: These results indicate that the Elecsys® HIV Duo assay is appropriate for use in the diagnosis of HIV and for screening of blood donations and is sensitive for the early detection of HIV.

Glycerol-induced positional nystagmus in human beings.

Direction-changing nystagmus has been seen after the ingestion of ethanol in both animals and man. The direction of the nystagmus is dependent upon the position of the head and is thus called Positional Alcohol Nystagmus (PAN). This article provides information about positionally dependent, direction-changing nystagmus in human beings after the ingestion of glycerol (1.5 g/kg). Electronystagmographic recordings were made and serum glycerol levels were repeatedly determined over a period of 7 hours. The resulting data compliment earlier work done with ethanol. These data provide support for a buoyancy hypothesis to explain positional nystagmus after ingestion of water-soluble molecules with differing specific gravities.

Evaluation of the anti-microbial and anti-inflammatory activities of the medicinal plants Dodonaea viscosa, Rumex nervosus and Rumex abyssinicus.

The crude extracts of the leaves of Dodonaea viscosa and Rumex nervosus as well as of the root of Rumex abyssinicus were tested for anti-microbial and anti-inflammatory activities. It was observed that the three plants possess antibacterial activity against Streptococcus pyogenes and Staphylococcus aureus and strong activity against Coxsackie virus B3 and influenza A virus. In contrast, none of them exhibited anti-fungal activity. The anti-inflammatory activity test results verified that only R. abyssinicus inhibited the synthesis of prostaglandin (PG) E(2).

Evaluation of the release profiles of flavonoids from topical formulations of the crude extract of the leaves of Dodonea viscosa (Sapindaceae).

Quercetin and isorhamnetin are found in adequately large concentrations in the plant Dodonea viscosa (Sapindaceae). Plants that contain flavonoids are effective in the topical treatment of skin or mucous membrane inflammation. In this study, the release profiles of quercetin and isorhamnetin from hydrophilic, amphiphilic and lipophilic creams of the crude extract of Dodonea viscosa were determined using a multilayer membrane system. The results revealed that the hydrophilic cream provided the highest rate of release of both flavonoids while there was practically no release from the lipophilic cream. The hydrophilic cream may, therefore, serve most in delivering flavonoids to a diseased skin.

Two distinct quasifission modes in the 32S + 232Th reaction.

Comprehensive fission measurements, including mass-angle distributions, for the reaction of 32S with the prolate deformed nucleus 232Th at near-barrier energies show two distinct components in both mass and angle; surprisingly, both have characteristics of quasifission. Their relative probabilities vary rapidly with the ratio of the beam energy to the capture barrier, suggesting a relationship with deformation aligned (sub-barrier), or antialigned (above-barrier), configurations at contact.

Disentangling effects of nuclear structure in heavy element formation.

Forming the same heavy compound nucleus with different isotopes of the projectile and target elements allows nuclear structure effects in the entrance channel (resulting in static deformation) and in the dinuclear system to be disentangled. Using three isotopes of Ti and W, forming 232Cm, with measurement spanning the capture barrier energies, alignment of the heavy prolate deformed nucleus is shown to be the main reason for the broadening of the mass distribution of the quasifission fragments as the beam energy is reduced. The complex, consistently evolving mass-angle correlations that are observed carry more information than the integrated mass or angular distributions, and should severely test models of quasifission.

Isospin symmetry of odd-odd mirror nuclei: identification of excited states in N=Z-2 48Mn.

Excited states have been observed in the N=Z-2 odd-odd nucleus 48Mn for the first time. Through comparison with the structure of 48V, a first high-spin study of an odd-odd mirror pair has been achieved. Differences between the T=1 analogue states in this pair have been interpreted in terms of Coulomb effects, with the aid of shell-model calculations in the full pf valence space. Unlike other mirror pairs, the energy differences have been interpreted almost entirely as due to a monopole effect associated with smooth changes in radius (or deformation) as a function of angular momentum. In addition, the large energy shift between analogue negative-parity states is interpreted in terms of the electromagnetic spin-orbit interaction in nuclei.

South Dakota solo practitioners' opinions about medicare.

The Federal government has embarked upon a strategy designed to contain or reduce costs associated with the Medicare system. This strategy has had the twin goals of reducing hospital costs for the Medicare program and also reducing payments to physicians. More emphasis has been placed on the hospital costs, but physician costs are also being attacked. The Medicare system projects that about one out of eight hospitals across the country will soon be closed. How do South Dakota physicians feel about these changes being imposed by Medicare? One hundred and three solo practitioners were polled and the results strongly suggest that South Dakota's hospitals are at considerable risk of closing. The Medicare position of wanting to close hospitals is in direct opposition to the state policy of wishing to provide medical practitioners and hospitals to smaller towns.

Medicare is closing smaller hospitals.

A previous article by the author reported responses to individual questions from a survey sent to solo practitioners in South Dakota. The survey responses were noted to have some correlations which have been extracted for this article. These correlations reveal a systematic bias against small town hospitals and small town doctors by the Medicare rules and the application of those rules. It appears that Medicare is acting vigorously to fulfill a prediction made by the head of the Health Care Financing Administration to close one out of eight hospitals in the United States. It further appears that almost all of the hospitals being closed are small hospitals which have lower costs. In this situation, small towns will have difficulty in attracting and keeping physicians.

Vascular hemodynamics: deep rooted misconceptions misnomers.

Erroneous concepts about vascular hemodynamics are widespread, notably as regards the effect of gravity on blood flow. Vascular pressure at any point is equal to the sum of two pressures of entirely different origins: (1) pressure caused by the pumping action of the heart ('cardiodynamic' pressure which is vital for circulation) and (2) pressure due to gravity acting on the blood ('gravitational' or hydrostatic pressure which plays no direct role in blood flow). Gravity neither helps nor hinders circulation because of the U tube or siphon principle. The gravitational energy of the column of blood in arteries is balanced exactly by the gravitational energy of the column in veins and vice versa. Thus, contrary to common belief, gravity does not hinder blood flow to the head in the upright position, nor does it hinder venous return from the dependent parts of the body. For this reason, in Poiseuille's equation, perfusion pressure should exclude gravitational pressure. Postural effects on circulation result from the distension vessels (particulary veins) subsequent to changes in gravitational pressure of blood.

Involuntary ankle oscillations from normal subjects.

Spectral analysis of ankle tremor records obtained from normal seated subjects during continuous elevation of the heel for 10-45 min revealed that the root-mean-square (rms) displacement amplitude of the tremor increased from minimum values of about 4 micronm to values as large as 4,000 micronm. Associated with this increase in the displacement amplitude was a systematic decrease in the tremor frequency from values of 7-8 Hz to values of 5-6 Hz. Spectral analysis of demodulated soleus EMG records indicated that the rms value of this EMG (calculated at the tremor frequency) and the rms displacement of the tremor are related by a power function, with the rms value of the EMG increasing over a range of about 4-40 micronV as the tremor displacement increased from about 4 to 4,000 micronm. The negative relation between frequency and rms displacement amplitude values for postural ankle tremor was similar to that found previously for postural hand tremor.

Properties of the pyramidal tract neuron system within the precentral wrist and hand area of primate motor cortex.

1. To obtain basic anatomical data that will be useful in interpreting the results of studies of primate pyramidal tract neurons (PTNs), extracellular, single-unit recording techniques were used to determine a number of the properties of the PTN population within the electrically defined, precentral wrist zone of the monkey's motor cortex. 2. Recordings were obtained from a total of 1,375 antidromically identified PT and corticospinal tract (CST) cells. A mathematical model was then used to correct the statistics of the sample for variations in the probability of unit detection, which arise from variations in neuronal size and extracellular field dimensions. 3. Both the experimentally observed and theoretically corrected results suggest that the PT projection from this cortical zone is derived principally from slowly conducting, and presumably small to medium-sized cells (an estimated 85% of the resident PTN population). 4. Both the fast and slow cell subpopulations were found to be concentrated within cortical layer V, where they tend to congregate in small, mixed clusters of 2 to 5 neurons. Estimates of the total packing density of PTNs within layer V of this cortical zone suggest that they account for only 10-20% of the neurons within this major efferent layer. 5. 70% of the slow and 82% of the fast PT neurons within this cortical area were found to send their axons into the contralateral, lateral corticospinal tract. Thus, in futur functional studies of PTNs in this cortical area, it can be assumed that three of every four neurons will in fact influence segmental cells of one category or another directly. 6. Extensive data are also presented on the incidence of axon collateral branching from PT and CST cells to the red nucleus, the medial medullary reticular formation and the cuneate nucleus. 7. Some general implications of these findings for the design of future functional studies of anatomically identified motor cortex cell systems are then discussed.

Effective charges in the fp shell.

Following the heavy-ion fusion-evaporation reaction 32S+24Mg at 95 MeV beam energy the lifetimes of analogue states in the T(z)=+/-1/2 A=51 mirror nuclei 51Fe and 51Mn have been measured using the Cologne plunger device coupled to the GASP gamma-ray spectrometer. The deduced B(E2;27/2(-)-->23/2(-)) values afford a unique opportunity to probe isoscalar and isovector polarization charges and to derive effective proton and neutron charges, epsilon(p) and epsilon(n), in the fp shell. A comparison between the experimental results and several different large-scale shell-model calculations yields epsilon(p) approximately 1.15e and epsilon(n) approximately 0.80e.