Physical learning environments' supportiveness to innovative pedagogies: students' and teachers' experiences.

Research into the relationship between innovative physical learning environments (PLEs) and innovative psychosocial learning environments (PSLEs) indicates that it must be understood as a network of relationships between multiple psychosocial and physical aspects. Actors shape this network by attaching meanings to these aspects and their relationships in a continuous process of gaining and exchanging experiences. This study used a psychosocial-physical, relational approach for exploring teachers' and students' experiences with six innovative PLEs in a higher educational institute, with the application of a psychosocial-physical relationship (PPR) framework. This framework, which brings together the multitude of PLE and PSLE aspects, was used to map and analyse teachers' and students' experiences that were gathered in focus group interviews. The PPR framework proved useful in analysing the results and comparing them with previous research. Previously-identified relationships were confirmed, clarified, and nuanced. The results underline the importance of the attunement of system aspects to pedagogical and spatial changes, and of a psychosocial-physical relational approach in designing and implementing new learning environments, including the involvement of actors in the discourse within and between the different system levels. Interventions can be less invasive, resistance to processes could be reduced, and innovative PLEs could be used more effectively.

A chromatin-associated kinesin-related protein required for normal mitotic chromosome segregation in Drosophila.

The tiovivo (tio) gene of Drosophila encodes a kinesin-related protein, KLP38B, that colocalizes with condensed chromatin during cell division. Wild-type function of the tio gene product KLP38B is required for normal chromosome segregation during mitosis. Mitotic cells in tio larval brains displayed circular mitotic figures, increased ploidy, and abnormal anaphase figures. KLP38B mRNA is maternally provided and expressed in cells about to undergo division. We propose that KLP38B, perhaps redundantly with other chromosome-associated microtubule motor proteins, contributes to interactions between chromosome arms and microtubules important for establishing bipolar attachment of chromosomes and assembly of stable bipolar spindles.

Sex steroids do not alter melatonin secretion in the human.

It is unclear whether sex steroids influence melatonin secretion in the human. In an attempt to find an answer to this important question 36 women within an age range of 19 to 40 years were studied within a 3-month period under the following conditions: natural menstrual cycle, ovulation induction with gonadotrophins, early pregnancy, and intake of monophasic or triphasic oral contraceptives. Except in the case of pregnancy, repeated measurements in the same individual were done because of the well-known large inter-individual variations in melatonin secretion. Melatonin concentration was measured in plasma samples obtained at 4-hourly intervals in a 24 h period and < 200 lux for all subjects studied. No consistent change in melatonin blood concentrations was demonstrated in response to the varying endogenous or exogenous concentrations of sex steroids. These observations suggest that circadian melatonin secretion is not significantly modulated by sex steroids.

PIP: The pineal gland hormone, melatonin, has been increasingly thought to play a significant role in the ovarian cycle. Though the evidence is unclear, some research suggests a pineal gland-ovary connection based on melatonin production during different phases in the ovarian cycle. This article reports the findings of a study on the effects of endogenous and exogenous sex steroids on melatonin secretion. 36 German women were studied over a 3-month summer period. This timing was intended to minimize the effects of seasonal influences on the women. Blood was taken every 4 hours (a total of 7 blood samples per day). Four groups were studied: women with natural menstrual cycles; 10-week pregnant women; women being treated with human menopausal/human chorionic gonadotropin; and women using phasic oral contraceptives. Melatonin was extracted from blood by using Bond Elut reverse-phase C18 columns. Statistical analysis included normal distribution, non-parametric analysis, and standard statistical analysis methods. No consistent change in melatonin blood levels was found in response to the varying endogenous and exogenous sex steroid levels. These findings suggest that circadian melatonin secretion is not modulated by sex steroids in a significant way.

Dodeca satellite: a conserved G+C-rich satellite from the centromeric heterochromatin of Drosophila melanogaster.

To identify sequences from the centromeric region, we have constructed a Drosophila melanogaster yeast artificial chromosome (YAC) library and screened it with purified DNA from the minichromosome Dp(1;f)1187 derived from the X chromosome. We describe the structure of one clone isolated in this way. This YAC is structurally unstable and contains tandemly repeated G+C-rich 11-mer and 12-mer units, which we call dodeca satellite. Most of this satellite is located near the centromere of an autosome. Cross-hybridizing sequences are found in the genomes of organisms as distant as Arabidopsis thaliana and Homo sapiens.

Melatonin and the ovulatory luteinizing hormone surge.

A newly developed 125I-radioimmunoassay allows for the accurate determination of physiological concentrations of plasma melatonin. Melatonin secretion does not change significantly on the day before and the day of the luteinizing hormone (LH) surge when compared with the early follicular phase. In addition, it was confirmed that the beginning of the LH surge frequently occurs in the morning and is associated with low melatonin values (six of nine women). Supraphysiological melatonin concentrations did not decrease the midcycle LH secretion in four women studied.

Isolation of mesoderm-specific genes expressed in the Drosophila embryo.

Tissue differentiation during embryonic development involves activation of specific genes. To isolate genes selectively expressed in mesoderm and nervous system in the Drosophila embryo, we have screened a cDNA library with molecular probes enriched in specific gene sequences from both tissues. In this way, we have isolated six mesoderm-specific genes, as demonstrated by in situ hybridization to embryo sections. Two of these genes, expressed during muscle differentiation, are described here for the first time. These genes have been localized in the 17A region of the first chromosome and in the 60A region of the second chromosome, respectively. No neural-specific genes were identified using this approach, most probably because of the low sensitivity of detection methods which combine filter hybridization techniques with the use of complex probes.

Two-dimensional protein analysis at high resolution on a microscale.

Proteins from small amounts of biological material are separated at high resolution by micro two-dimensional gel electrophoresis. Under nonequilibrium conditions, proteins are focused in 10-microliters capillaries and separated on ultrathin slab gels. Our device allows simultaneous focusing of up to 10 samples which can be processed in the second dimension on a single gel. Several hundred protein spots from less than a total of 300 ng of protein are resolved on an area the size of a postage stamp. A single spot containing less than 10 pg of protein or 1 cpm can be detected by silver staining or autoradiography, respectively. Our system allows inexpensive, simultaneous, rapid analysis of proteins when only a limited amount of biological material is available for investigation. A detailed description of the equipment, the methods, and the characteristics of this microanalysis are presented.