Generalized bond order parameters to characterize transient crystals.

Higher order parameters in the hard disk fluid are computed to investigate the number, the lifetime, and size of transient crystal nuclei in the pre-freezing phase. The methodology introduces further neighbor shells bond orientational order parameters and coarse-grains the correlation functions needed for the evaluation of the stress autocorrelation function for the viscosity. We successfully reproduce results by the previous collision method for the pair orientational correlation function, but some two orders of magnitude faster. This speed-up allows calculating the time dependent four body orientational correlation between two different pairs of particles as a function of their separation, needed to characterize the size of the transient crystals. The result is that the slow decay of the stress autocorrelation function near freezing is due to a large number of rather small crystal nuclei lasting long enough to lead to the molasses tail.

Instability in pipe flow.

The long-puzzling, unphysical result that linear stability analyses lead to no transition in pipe flow, even at infinite Reynolds number, is ascribed to the use of stick boundary conditions, because they ignore the amplitude variations associated with the roughness of the wall. Once that length scale is introduced (here, crudely, through a corrugated pipe), linear stability analyses lead to stable vortex formation at low Reynolds number above a finite amplitude of the corrugation and unsteady flow at a higher Reynolds number, where indications are that the vortex dislodges. Remarkably, extrapolation to infinite Reynolds number of both of these transitions leads to a finite and nearly identical value of the amplitude, implying that below this amplitude, the vortex cannot form because the wall is too smooth and, hence, stick boundary results prevail.

Modulation of the satiating effect of amylin by central ghrelin, leptin and insulin.

Amylin is a pancreatic hormone that is considered to be a satiating signal acting on neurons of the area postrema (AP) in the hindbrain. The adiposity signals leptin and insulin act in the hypothalamus to influence feeding. They also enhance the hindbrain's responsivity to satiating signals, e.g. cholecystokinin (CCK). The orexigenic hormone ghrelin is thought to use the same hypothalamic pathways as leptin and insulin, with opposite actions on feeding behaviour. In fact, CCK and ghrelin also seem to interact in the control of feeding. Because CCK's anorectic effect depends on endogenous amylin, the aim of this study was therefore to evaluate a possible functional interaction between amylin and these hormones on short-term food intake in rats. The experiments were performed with male Wistar rats. Intracerebroventricular injection (i3vt) of an orexigenic dose of ghrelin (5 ng/5 microl) reduced but did not completely reverse the intraperitoneal amylin (5 microg/kg)-induced inhibition of food intake. In comparison, administration of a sub-threshold dose of ghrelin (3 ng/5 microl) did not affect the anorexigenic action of peripheral amylin. Leptin administered into the third ventricle (i3vt; 3.5 microg/5 microl) and intraperitoneal amylin (5 microg/kg) synergistically reduced food intake in chow-fed rats. I3vt insulin, administered at a sub-threshold dose (0.5 mU/5 microl), significantly enhanced the response to peripheral amylin. These results indicate that the lipostatic signals leptin and insulin may synergize with amylin to reduce food intake. In contrast, under the conditions tested, the orexigenic hormone ghrelin does not seem to influence the feeding response to peripheral amylin.

[Neuroleptics in the newspaper. A mass media analysis]. / Neuroleptika in der Zeitung. Eine Medienanalyse.

OBJECTIVE: Neuroleptic drugs have a dubious public reputation. Many people consider them obnoxious, even in schizophrenia. METHOD: 10 annual editions of six German language opinion leading newspapers are analysed. RESULTS: Only in one of 35 articles neuroleptics are judged positive, in 27 negative. They are seen close to violence and restriction, as punishment or even as torture, as paralyzing or even as "torturetherapy". Informations in the articles are scarce. Most of the articles cover the fields of medicine or psychiatry or of forensics. CONCLUSION: Apart from the negative attitude the extremely low number of articles on neuroleptics is the most outstanding result of our study.

[Tranquilizers in the newspaper. An media analysis]. / Tranquilizer in der Zeitung. Eine Medienanalyse.

OBJECTIVE: For the public the image of psychopharmacological drugs is identical with that of minor tranquilizers. The way of describing and portraying these drugs in the media therefore is of general interest. METHOD: Ten annual volumes of six German language opinion leading daily and weekly papers which exist on CD-Rom in full text editions are screened for the key word "minor tranquilizer". The articles identified are analyzed formally quantatively and qualitatively. RESULTS: The ten annual volumes analyzed contained 45 articles in which tranquilizers were mentioned (4.5 per annual volume). The key words were found in all sections of the papers, most often, however, in the cultural section, followed by the science section. Regarding the themes medicine and law were in the first position (one third), but society, arts and culture and politics contained even more articles dealing with the key word minor tranquilizer. For fifth of the articles only mentioned the key word. Only once minor tranquilizers are the main topic of the article. Tranquilizers are valued negatively ten times as often as they are valued positively. In two fifth of the articles the term is employed as a metaphor. Even in this context minor tranquilizers are valued negatively (10:1). CONCLUSIONS: Three fourth of the articles, employing the term in the non metaphorical way, deal with abuse and dependency. The public image of minor tranquilizers in the media is mainly characterized by their potency to cause dependency.

A telephone intervention to reduce fatigue and symptom distress in mothers with difficult infants in the community.

The purpose of this study was to test the effectiveness of a telephone intervention to reduce fatigue and the resulting symptom distress of mothers in Iceland who reported having a behaviourally difficult infant of 2-3 months of age. A sample of 78 mothers who reached distress criteria of depressive symptoms and parental stress was selected and randomly allocated in a controlled experimental study. In a brief intervention both maternal distress and infant difficulty were discussed. Results indicate a significant (P < 0.001) intervention effect on fatigue and its side-effects. It is concluded that intervention by telephone can be effective with fatigued mothers caring for a difficult infant.

[Electroconvulsive therapy and defibrillation in the paper. An analysis of the media]. / Die Elektrokrampftherapie und die Defibrillation in der Zeitung. Eine Medienanalyse.

In our study on Psychiatry, Mass Media and Public Opinion we made a content analysis of newspaper reports on ECT and electric defibrillation. We traced only few special articles on the subject in the 1994 and 1995 CD-Rom versions of the "Der Spiegel", The "Frankfurter Allgemeine Zeitung" (FAZ), the "Neue Zürcher Zeitung" (NZZ) and the "Berliner Tageszeitung" (taz), although the word "Elektroschock" was employed 118 times. Even in high standard newspapers the style of language becomes special when they deal with ECT. The articles are strongly biased and lack informations. In contrast to Defibrillation ECT is not generally accepted. Referring to ECT horror pictures of past psychiatry are cited. The language used is biased and discriminative. Referring to Defibrillation technical details are described and the language is neutral. The social representation of ECT is completely negative.

[Schizophrenia in the "New Zurich Newspaper". A media analysis]. / Schizophrenie in der "Neuen Zürcher Zeitung". Eine Medienanalyse.

Social representations of mental illness and psychiatry are largely influenced by mass media. This study explores the use of the term "schizophrenia" in the Swiss newspaper NZZ in 1994 and 1995, the text of which is available on CD-ROM. In 31% of the cases the term is used figuratively, i.e. as a metaphor. When used as a name of an illness, it reflects contradictory connotations: schizophrenics as mentally ill offenders or criminal in the local columns, schizophrenics featuring as creative writers or artists in the cultural columns. Information on schizophrenia as disease is rare. If it does occur, reporting is rather sociopsychiatric than neurobiological.

[Electroconvulsive therapy, electroshock and shock therapy in the newspaper]. / Elektrokrampftherapie, Elektroschock und Schocktherapie in der Zeitung.

Newspapers reports on ECT are extremely biased. A quantitative analysis of four German and Swiss papers demonstrates impressingly the change of meaning of synonymous terms like "Elektroschock" and "Schocktherapie" which refer to torture and brutal reforms of Eastern European communist economies.

Comparison of hemagglutination and solid phase titration methods for determination of critical prenatal antibody titers.

The hemagglutination (HA) tube method is the standard method for determination of antibody titer in prenatal samples. Most facilities use a titer between 8 and 32 as their definition of a critical value when amniocentesis may be considered. This study determined if there is a relationship between the results of HA tube and solid phase (SP) titers performed on the same sample. Forty-six paired samples containing known antibody were titrated by both HA tube and SP methods and the results subjected to data analysis. We conclude that there is a strong correlation between HA tube and SP methods in titer end points; i.e., SP was greater than or equal to HA in every case. In addition, the appropriate critical SP titer is 64, which is at least equivalent to an HA critical titer of 16.

Hypothalamic release of atrial natriuretic factor and beta-endorphin into rat hypophysial portal plasma: relationship to oestrous cycle and effects of hypophysectomy.

The release of beta-endorphin and atrial natriuretic factor (ANF) into hypophysial portal plasma was investigated in male and female Wistar rats. The principal aim of the study was to investigate the possible role of beta-endorphin and ANF in the hypothalamic control of LH and prolactin secretion. In male rats, anaesthetized with urethane, the concentrations of beta-endorphin in portal blood collected immediately after hypophysectomy were within the same range as those in peripheral plasma. Furthermore, electrical stimulation of the median eminence did not increase the portal plasma concentrations of beta-endorphin. In female rats, anaesthetized with alphaxalone, the portal plasma concentrations in long-term (6-8 weeks) or acutely hypophysectomized rats were significantly greater than those in peripheral plasma. In acutely hypophysectomized female rats the concentrations and contents of beta-endorphin in portal plasma collected at 10.00-11.30 h of pro-oestrus were significantly (approximately sixfold) greater than at dioestrus or at 20.00-21.00 h of pro-oestrus, but these changes were not consistently seen in all experiments. In female rats in which the pituitary gland was not removed for portal blood collection, portal plasma contents of ANF remained unchanged throughout the day of pro-oestrus, suggesting that it is unlikely that ANF is involved in the spontaneous LH or prolactin surge. The effects of ovarian steroids on the secretion of hypothalamic ANF and beta-endorphin were determined by measuring the portal plasma concentration of ANF and beta-endorphin on the morning of presumptive pro-oestrus in rats ovariectomized 24 h previously and injected with either oil or oestradial benzoate (OB). Portal plasma contents of ANF were significantly lower in OB- compared with oil-treated rats, suggesting that oestradiol inhibits ANF release into rat hypophysial portal plasma. In contrast, there were no significant between-group differences in the content or concentration of beta-endorphin in portal plasma. Thus, the increased beta-endorphin in the portal plasma of some of the intact animals during the morning of pro-oestrus is not due to the preovulatory surge of oestradiol-17 beta. The output of beta-endorphin into portal blood in long-term hypophysectomized rats was lower than in dioestrous or pro-oestrous rats in which the pituitary gland was removed immediately before portal blood collection.(ABSTRACT TRUNCATED AT 400 WORDS)

Immunoreactive ACTH, beta-endorphin, and cortisol levels in plasma following spinal manipulative therapy.

This study examines the possibility of a humorally mediated analgesic response to spinal manipulative therapy by determination of plasma levels of beta-endorphin, adrenocorticotropic hormone (ACTH), and cortisol before and after intervention. Forty male subjects (20 symptomatic, 20 asymptomatic) were allocated into four equal groups. Two treatment groups were given spinal manipulative therapy, and two groups underwent a sham procedure. Blood samples were taken via indwelling butterfly needles pre- and postintervention in all four groups, and levels of immunoreactive ACTH, immunoreactive beta-endorphin, and cortisol determined by radioimmunoassay. No differences in ACTH or beta-endorphin were found between sham and treated groups, or between pre- and postintervention in any group; cortisol levels fell over the course of the study in all groups. The findings thus appear to exclude a humoral role for beta-endorphin in mediating the analgesic response to spinal manipulative therapy; in addition, they suggest that such therapy is not a stressor that activates the hypothalamo-pituitary-adrenal axis.

Determination of bovine lymphocyte responses to extracted proteins of Brucella abortus by using protein immunoblotting.

Isolation and identification of Brucella antigenic determinants important to cellular responses have been difficult. In this study, bovine peripheral blood mononuclear (PBM) cells from cattle vaccinated with Brucella abortus 19 proliferated to extracted bacterial proteins blotted onto nitrocellulose. Proteins were extracted from gamma-irradiated B. abortus 19 with a sodium dodecyl sulfate extraction buffer. The extracted proteins were separated electrophoretically by sodium dodecyl sulfate-polyacrylamide gel electrophoresis prior to electroblotting onto nitrocellulose. Nitrocellulose sections corresponding to individual lanes of the gel (containing all separated proteins) were then cultured with the PBM cells. Primary and secondary stimulation responses of the PBM cells with the whole protein blots were similar kinetically to the responses of the PBM cells stimulated with whole irradiated B. abortus 19 or with whole irradiated B. abortus 19 blotted onto nitrocellulose. Although lipopolysaccharide was determined to be associated with the extracted proteins and transferred onto the blots, the lipopolysaccharide did not stimulate cellular proliferation, as indicated by the antigen-specific secondary responses. Stimulating PBM cells with portions of the blot containing high (greater than 45,000)-, medium (25,000 to 45,000)- or low (25,000)-molecular-weight proteins demonstrated that the responding cells were specific only to the proteins of corresponding molecular weights. These results indicate that cellular responses to individual proteins can be studied without cloning the bacterial genes or purifying the individual proteins.

Plasmodium berghei malaria: effect of acute phase serum on immunity generated in rats by infection and by vaccination.

Acute phase serum (APS) given at the time of challenge with Plasmodium berghei inhibited the generation to immunity to the infecting plasmodia. Administered with a single dose of vaccine, it inhibited induction of immunity by the vaccine. Three weekly doses, the last given two weeks before infection, induced immunity. Administration of vaccine simultaneously with infection neither aggravated nor ameliorated the infection. These results indicate that the effect of administration of APS on immunity generated by immunization or infection is dose- and time-dependent. The depression of immunity induced by this serum is thus temporary, the host finally overcoming the depression and responding to the plasmodial antigen in the serum. The interaction of vaccine and infection observed indicates that the introduction of vaccine is not detrimental to the individual incubating infection; rather, the vaccine is rendered useless, the reducing the aggregate benefit of the immunization to the group.

Quantum monte carlo.

An outline of a random walk computational method for solving the Schrödinger equation for many interacting particles is given, together with a survey of results achieved so far and of applications that remain to be explored. Monte Carlo simulations can be used to calculate accurately the bulk properties of the light elements hydrogen, helium, and lithium as well as the properties of the isolated atoms and of molecules made up from these elements. It is now possible to make reliable predictions of the behavior of these substances under experimentally difficult conditions, such as high pressure, and of properties that are difficult to measure experimentally, such as the momentum distribution in superfluid helium. For chemical systems, the stochastic method has a number of advantages over the widely used variational approach to determine ground-state properties, namely fast convergence to the exact result within objectively established error bounds.

Phase separation in mixtures of ionized iron in a hydrogen plasma.

The accuracy of the hypernetted chain theory for mixtures of iron nuclei and protons in a charge-neutralizing background is demonstrated by comparison with molecular dynamics calculations. Near critical conditions the Debye-Hückel approximation fails to converge, even with second-order concentration corrections. The critical conditions, determined by assuming a uniform electron gas background, have a critical temperature more than a factor of 2 lower than present estimates of interior solar conditions. Qualitative arguments are made that including the polarization of the electron gas background would not change this result significantly and thus phase separation of iron in the interior of the sun is unlikely.

Dielectric constant of atomic fluids with variable polarizability.

The Clausius-Mossotti function for the dielectric constant is expanded in terms of single atom and pair polarizabilities, leading to contributions that depend on both the trace and the anisotropy of the pair-polarizability tensor. The short-range contribution of the anisotropic part to the pair polarizabilities has previously been obtained empirically from light scattering experiments, whereas the trace contribution is now empirically determined by comparison to dielectric experiments. For helium, the short-range trace part agrees well with electronic structure calculations, whereas for argon qualitative agreement is achieved.

Relation between the local field at large distances from a charge or dipole and the dielectric constant.

The local field at large distances from a charged or dipolar impurity in a nonpolar polarizable fluid is related to the dielectric constant of the medium. The predicted local field agrees accurately with molecular dynamics results. In contrast, the usual continuum theory prediction is only accurate to first order in the polarizability and leads to serious error for realistic values of the polarizability. At smaller distances these relations cannot be used to define a physically reasonable local dielectric constant and consequently the local field is more satisfactorily described in terms of a screening function.

Aluminum-26 in pacific sediment: implications.

Aluminum-26 has been detected in a sample of sediment from the South Pacific. The disintegration rate of 0.8 disintegration per minute per kilogram of dry sediment is considerably higher than that expected from cosmic-ray spallation of atmospheric argon; it appears to result mainly from accretion of activity induced in interplanetary dust by solar-flare particles. This finding is in keeping with Wasson's published estimates regarding the magnitude of this effect, and confirms the order-of-magnitude correctness of the solar-particle flux and terrestrial accretion rate of interplanetary dust used in that calculation.