Producing and imaging a thin line of He*2 molecular tracers in helium-4.

Cryogenic helium-4 has long been recognized as a useful material in fluids research. The unique properties of helium-4 in the gaseous phase and the normal liquid phase allow for the generation of turbulent flows with exceptionally high Reynolds and Rayleigh numbers. In the superfluid phase, helium-4 exhibits two-fluid hydrodynamics and possesses fascinating properties due to its quantum nature. However, studying the flows in helium-4 has been very challenging largely due to the lack of effective visualization and velocimetry techniques. In this article, we discuss the development of novel instrumentation for flow-visualization in helium based on the generation and imaging of thin lines of metastable He*2 tracer molecules. These molecular tracers are created via femtosecond-laser field-ionization of helium atoms and can be imaged using a laser-induced fluorescence technique. By observing the displacement and distortion of the tracer lines in helium, quantitative information about the flow field can be extracted. We present experimental results in the study of thermal counterflow in superfluid helium that validate the concept of this technique. We also discuss anticipated future developments of this powerful visualization technique.

Higher luteal progesterone is associated with low levels of premenstrual aggressive behavior and fatigue.

Contradictory findings show both positive and negative effect of progesterone on the premenstrual mood changes in women. Here we present the study investigating this relationship on the large sample of premenstrual women. 122 healthy, reproductive age women collected daily morning saliva samples and recorded intensity scores for the mood symptoms: irritability, anger, sadness, tearfulness, insomnia, and fatigue. Saliva samples were assayed for progesterone concentrations and mood intensity scores were used to calculate behavioral indices. Women with low Aggression/Irritability and Fatigue had consistently higher progesterone levels during the luteal phase than women with high Aggression/Irritability and Fatigue. Additionally, Aggression/Irritability and Fatigue correlated negatively with maximal progesterone value during the luteal phase. Our results demonstrated a negative effect of low progesterone level on the premenstrual mood symptoms such as aggressive behavior and fatigue in healthy reproductive age women. This supports a previously proposed model of biphasic action of progesterone metabolites on mood.

Impact of economic conditions on the secondary sex ratio in a post-communist economy.

According to the Trivers-Willard hypothesis the secondary sex ratio (SSR, the ratio of male to female newborns [M/F]) should be positively related to the parents' living conditions. This also means that if in some population parents experience environmental (e.g. economic) stress, the SSR should be relatively low. If this holds true, the fluctuations in the SSR of offspring could be one of the ways the human population reacts to environmental (and also socio-economic) changes. Although confirmed for many human populations, such a relationship was not observed in the populations living in the communist-era planned-economy countries until recently. We test the hypothesis that economic stress in Poland after the communist era is also related to the SSR decrease. Using quarterly data from the years 1995-2007 about the total number of live male (M) and female (F) newborns born in central Poland (sample size=310,532), we calculated the time series of the SSR. The quarterly economic conditions of the studied population within the period under consideration constituted the time series of the percentage change in private consumption at constant prices of the year 2000. The relationship between the SSR and the economic conditions in the analyzed 47 quarters of the year was tested with the use of the ARMA models. We have found that four quarters (one year) after the occurrence of economic stress there was a decline in the SSR. This result is consistent with the Trivers-Willard hypothesis at the population level in a modern free-trade economy of a post-communist country.

Waist-to-hip ratio versus body mass index as predictors of fitness in women.

The claim that men prefer women with low waist-to-hip ratios (WHR) has been vigorously disputed. We examine self-report data from 359 primiparous Polish women (with normal singleton births and healthy infants) and show that WHR correlates with at least one component of a woman's biological fitness (her first child's birth weight, a variable that significantly affects infant survival rates). However, a woman's Body Mass Index (BMI) is a better predictor of her child's neonatal weight in small-bodied women (<54 kg). The failure to find a preference for low WHR in some traditional populations may thus be a consequence of the fact that, even in western populations, body mass is a better predictor of fitness in those cases characterized by low maternal body weight.

Prevalence of menstrual pain in relation to the reproductive life history of women from the Mayan rural community.

BACKGROUND: The prevalence of menstrual pain in Western societies is relatively high and has been shown to be related to many factors (e.g. age, menarche age, parity, menstrual cycle regularity, cigarette smoking, dietary habits). However, less data are available for traditional societies, within which there are, presumably, not as many potentially disturbing factors that could influence menstrual symptoms as in Western societies. AIM: The study seeks to determine the prevalence of dysmenorrhoea, and the factors related to menstrual pains in women with natural fertility (i.e. without hormonal forms of contraception). SUBJECTS AND METHODS: 177 non-smoking women between 18 and 45 years of age living in one Mayan village (Yaxcaba, Yucatan, Mexico) were the subjects of this study. The method of logistic regression was used with the dichotomous dependent variable being the presence or absence of menstrual pain together with such independent variables as age, age at menarche, number of pregnancies, age when giving birth to the first child, the weight at interview and BMI. RESULTS: The general prevalence of the menstrual pains was 28%. There was only one variable influencing dysmenorrhoea, namely the age at which women give birth to their first children. Those mothers who gave birth to their first child at an earlier age (at mean age of 19.4 vs 21.1 years) had a lower prevalence of dysmenorrhoea. CONCLUSION: In the studied traditional society the main factor related to menstrual pain was the age at which woman first gave birth. It is hypothesized that an earlier start to reproductive life in some way decreases the sensitivity of the uterus to prostaglandins.

Can the sex of the second child be predicted by the birth-weight of the first child?

The reproduction costs to a human mother are different if she has a son as opposed to a daughter. According to the Trivers-Willard hypothesis, evolution should promote those females who, having the ability to invest in the more expensive sex, are also able to adjust the sex of their offspring accordingly. It is therefore possible that a mother's biological condition (which is also connected with her reproductive potential), as measured by the neonatal weight of her first child, can be a good predictor of the second child's sex. From data for 227 healthy mothers from Wroclaw (Poland) we show that the probability of giving birth to a boy in the second pregnancy is higher after a relatively heavier first-born child (ANOVA, F(1,225)=3.79, P<0.053). This relationship, however, is only significant after a first-born daughter (F(1,117)=9.66, P<0.002) and not after a first-born boy. Some possible explanations of the fact that only the birth-weight of a first-born daughter--and not a son--can be a good predictor of the secondary sex ratio are also discussed.

Insulin Lispro in pregnancy--retrospective analysis of 33 cases and matched controls.

AIMS/HYPOTHESIS: To evaluate if the application of Lispro insulin in pregnancy increases the risk for malformations or unusual pregnancy courses. METHODS: Diabetes specialists were contacted in Germany and Austria and asked to report women with diabetes who had been treated with Lispro during pregnancy. Furthermore they were asked to report another pregnant diabetic woman treated with regular insulin with similar HbA1c and age for each Lispro case. Following data were requested: age, first HbA1c in pregnancy and time of analysis, start and duration of Lispro treatment, ultrasound examination, chorionic villi biopsy, amniocentesis, unusual pregnancy courses, standard examination of the new-born for any malformation. Two-sided 95% confidence limits (95%-CI) for risk differences of proportions of malformations or unusual pregnancy courses were calculated. RESULTS: 33 pregnant diabetic women with Lispro and 27 with regular insulin treatment were analysed (mean age 28.3 years (17-41)and 30.1 (19-40); mean HbA1c 6.9% (4.5-10.7) and 6.8% (4.7-9.8), respectively). There were four malformations or unusual pregnancy course (spontaneous abortion; elective interruption because of multiple malformations; heart malformations and hyaline membrane syndrom; premature birth) in the Lispro and one malformation (dyplastic hip) in the regular insulin group. Risk differences in proportions of malformation or unusual pregnancy courses were 8% (95%-CI: - 5% to 21%). CONCLUSIONS/INTERPRETATION: Risk differences for malformations or unusual pregnancy courses were not higher in the insulin Lispro group compared to the controls. However, we observed four malformations or unusual pregnancy courses in the Lispro group. A case-control study is suggested to get a precise risk estimate.

Impact of market value on human mate choice decisions.

Mate choice strategies are a process of negotiation in which individuals make bids that are constrained by their status in the market place. Humans provide an unusual perspective on this because we can measure their explicitly expressed preferences before they are forced to make any choices. We use advertisements placed in newspaper personal columns to examine, first, the extent to which evolutionary considerations affect the level of competition (or market value) during the reproductively active period of people's lives and, second, the extent to which market value influences individual's willingness to make strong demands of prospective mates. We show that female market value is determined principally by women's fecundity (and, to a lesser extent, reproductive value), while male market value is determined by men's earning potential and the risk of future pairbond termination (the conjoint probability that the male will either die or divorce his partner during the next 20 years). We then show that these selection preferences strongly influence the levels of demands that men and women make of prospective partners (although older males tend to overestimate their market value).

The influence of steady magnetic fields on the mouse hippocampal evoked potentials in vitro.

Direct current-generated EM fields modulated evoked potentials recorded from hippocampal slices. Both the synaptic efficiency represented by the slope of EPSP and the number of activated pyramidal cells represented by the population spike were modified by EM fields. While the weak EM fields (2-3 mT) exerted a biphasic effect observed as a transient small depression followed by a long-lasting amplification of the potentials, stronger EM fields (8-10 mT) depressed these potentials. This depression could be partially reversed by increasing the strength of the stimulation. It is suggested that EM-induced fluctuations in the intracellular Ca2+ concentration are responsible for the observed effect.

Pregnancies in women with diabetic nephropathy: long-term outcome for mother and child.

In order to improve the basis upon which to advise women with diabetic nephropathy about pregnancy, we studied the effect of diabetic nephropathy on the course of pregnancy, perinatal outcome, infant development and long-term outcome of the mothers. All pregnancies of women with diabetic nephropathy (defined as proteinuria > 400 mg/day (n = 26), creatinine clearance < 80 ml/min and hypertension in the first trimester (n = 10)) followed at our centre from 1982 to 1992 were identified (34 White class F and 2 White class T) and the women and their children re-examined in the spring 1993. From the first to the third trimester the percentage of women with proteinuria over 3 g/day increased from 14 to 53% and those treated with antihypertensive medication from 53 to 97%. There were no intrauterine or perinatal deaths, but one child died suddenly 4 weeks postpartum. Of 36 newborns (gestational week at birth 36(3), birth weight 2384(834) g)), 11 were born before week 34 and 8 had respiratory distress syndrome. Renal function in the first trimester, diastolic blood pressure in the third trimester and an HbA1c above normal were predictive of gestational age at delivery and low birth weight (stepwise regression analysis). At follow up of the children (n = 35, age 4.5 (0.4-10) years) the majority (n = 27) were normally developed but seven had psychomotor retardation (four of them major). One child had a severe motor retardation due to a congenital anomaly. At follow up, 21 of the 29 mothers had preserved renal function (creatinine 1.3 (0.8-4.3) mg/dl and 8 had developed end stage renal disease and required dialysis (2 of whom were White class T) within 3 (1-9) years postpartum.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of extraction and nonextraction orthodontic treatment on brachyfacial and dolichofacial growth patterns.

The effects of extraction and nonextraction orthodontic treatment mechanics on patients with dolichofacial and brachyfacial growth patterns between one and two standard deviations were studied. Groups underwent treatment of either nonextraction or extraction of four premolars with the appropriate mechanics for the facial type. Changes in the facial axis and correlation between maxillary molar movement and facial axis change were measured. A positive correlation was found between the amount of anteroposterior movement of the upper molar and change in the facial axis in brachyfacial and dolichofacial patients undergoing nonextraction treatment. A weak correlation was found in the extraction treatment groups. No statistically significant difference was found in the facial axis change among any of the groups studied, regardless of facial type or plan of treatment. There were indications of a more severe opening of the facial axis (Ba-Na plane to constructed gnathion) with greater degrees of maxillary molar distal movement in both facial patterns studied.

Natural course of remission in IDDM during 1st yr after diagnosis.

OBJECTIVE: To describe the natural course of clinical remission in insulin-dependent diabetes mellitus (IDDM) when insulin dose is minimized without loss of target glycemia and to identify factors that predict clinical remission. RESEARCH DESIGN AND METHODS: Ninety-five patients, who were placebo-treated control subjects in the Canadian-European multicenter randomized trial of cyclosporin A in recent-onset IDDM, were studied. RESULTS: The mean insulin dose decreased during the first months after diagnosis, with a nadir at 3 mo, when 27% of the patients did not require insulin to maintain target glycemia. At 1 yr, 10% of patients still did not need insulin. Patients not receiving insulin who had glycosylated hemoglobin within the normal range were called remitters. Mean basal and glucagon-stimulated C-peptide values were significantly (P less than 0.025) higher in remitters than nonremitters at the start of the study. Therefore, all patients were divided into those with values above the mean stimulated C-peptide (0.4 nM) and those with values below the mean at entry. The probability of entering a remission with a stimulated C-peptide greater than 0.4 nM was 10 times as high (P less than 0.05) as for those with a stimulated C-peptide below this level. Surprisingly, the beginning and end of the remission were associated with neither major changes in C-peptide levels nor islet cell antibody and insulin-antibody titer. A more rapid loss of stimulated C-peptide occurred in patients who lacked HLA-DR3 and -DR4 (P less than 0.05 at mo 9). CONCLUSIONS: This study shows a higher spontaneous clinical remission rate than expected during the 1st yr after diagnosis. Preserved beta-cell function at entry predicts a greater chance of entering a remission, and a more rapid loss of beta-cell function was seen in patients without HLA-DR3 and -DR4.

Computer ray tracing speeds.

The results of measuring the ray trace speed and compilation speed of thirty-nine computers in fifty-seven configurations, ranging from personal computers to super computers, are described. A correlation of ray trace speed has been made with the LINPACK benchmark which allows the ray trace speed to be estimated using LINPACK performance data. The results indicate that the latest generation of workstations, using CPUs based on RISC (Reduced Instruction Set Computer) technology, are as fast or faster than mainframe computers in compute-bound situations.