Secular changes in body formation of greek students

Anthropometric dimensions of 1520 students of Biology at University of Athens in Greece were analysed to determine secular changes of height and body proportions during a 20 year period. Since, 1970, means of standing height, subischial length, and cormic index have been increased, although the rate of increase from 1986 to 1990 has been rather slow. On the contrary the mean sitting height is stable, and cormic/ subischial index have been declined during the same period. There are no data for comparing this sample with the general population, but we suppose that these changes in the body formation is common as a result of the modern way of life.     

Natural vs. mariculture induced variability in nutrients and plankton in the eastern Mediterranean

The water column in three Mediterranean fish farms was investigated in terms of physical, chemical and biological characteristics. A significant increase in concentrations of phosphate and ammonium was detected within the cages over the control site in one of the farms but without any significant effect on chlorophyll concentration. Analysis of variation within the data set identified location and season as the major factors of variability in most of the variables examined except phosphate and ammonium for which variability induced by fish farming seemed to be of major importance. Plankton abundance for the major taxonomic groups (diatoms, flagellates, dinoflagellates and ciliates), microplankton species diversity and community structure were also determined by the effects of season and location rather than by fish farming.     

The ancient minoans of crete: A biodistance study

The study of cranial material is an important source of information for biological reconstruction of past human populations. Such cranial data used for solving prehistoric problems (Buikstra et al, 1990). Cranial samples from the prehistoric population of Crete were studied to try to answer an archaeological problem (the hypothesis of the Mycenean invasion in the island during Late Bronze Age period). Historical and archaeological evidence suggests that Myceneans invaded Crete after the destroy caused by the eruption of the Thera Volcano (15^th century b.C.). The samples were analysed by Discriminant Analysis, and classification factor was the Era. It is concluded that: a) It is not abvious an entry of another population during the transitional period between NL/MM, because there is a common morphometric pattern, and b) the entrance and installation of the Myceneans during the Late Minoan period is possible because a different morphometric pattern was found. This last conclusion is in accordance with the archaeological evidence.     

Muscle co-activation around the knee in drop jumping using the co-contraction index.

The purpose of this study was to examine the co-activation of the rectus femoris (RF) and biceps femoris (BF) during drop jumping exercises using the co-contraction index (CI). Ten trained male long jumpers performed drop jumps from 20 cm (DJ20), 40 cm (DJ40) and 60 cm (DJ60) on a force platform. Surface electromyographic (EMG) activity of the RF and BF, vertical ground reaction force data and knee joint angular displacement and angular velocities were recorded and normalized as percentage of maximum isometric values. The CI was calculated for the pre-contact, braking and propulsive phases of the jump using four methods: (1) by dividing the double integrated antagonistic activity by the sum of the RF and BF EMG; (2) by finding the amount of overlap between the linear envelopes of the agonist and antagonist muscles and dividing by the number of data points; (3) by calculating the co-contraction at any instant point of time; and (4) by dividing the BF integrated activity by the total registered muscle activity around the knee. The CI ranged from 13.03+/-9.33 to 70.80+/-25.81%, depending on the estimation method used. A two-way analysis of variance (ANOVA) indicated that the CI was not affected by drop jumping height (p>0.05) while it was significantly higher (p<0.05) in the pre-contact phase compared to the braking and propulsion phases. The CI can be useful when examining muscle co-activation using EMG measurements in drop jumps. However, the conclusions on muscle co-activation depend on the equation used to estimate CI and therefore a commonly accepted method is necessary.     

Characterization of purified leaf cytosolic pyruvate kinase from the C4 plant Cynodon dactylon

Cytosolic pyruvate kinase (EC 2.7.1.40) from leaves of the C₄ plant Cynodon dactylon (L.) Pers. was purified 56-fold to apparent homogeneity by polyethylene glycol fractionation and column chromatography including Q-Sepharose anion exchanger, ADP-Agarose and gel filtration. Nondenaturing PAGE of the final preparation resulted in a single protein band that co-migrated with the pyruvate kinase activity. Gel filtration and SDS-PAGE (± DTT) showed that this enzyme has a molecular mass of 200 kDa and is a homotetramer with a subunit molecular mass of 50 kDa. The subunits are not associated to each other with S-S bonds. The enzyme has a pH optimum of 6.2 and is heat stable. Typical Michaelis-Menten kinetics was obtained for both substrates, PEP and ADP, with K_m values of 64 and 235 μ M , respectively. Initial velocity studies indicated a sequential binding of the substrates to the enzyme.     

Geographical differentiation of cephalometric data of a nomadic isolated Hellenic population (Sarakatsani)

The scientific value of isolated human populations is important for the understanding of ethnic formation, or for micro-evolution. The population of Sarakatsani in HELLAS was nomadic up to 10–15 years ago. It may still be considered as nomadic since it migrates during winter and summer. We studied three Sarakatsanic groups, geographically isolated in Epirus, Central Macedonia and Peloponessos. Nine cephalometric variables were measured and subjected to Discriminant Function Analysis (DFA) and Analysis of Variance (ANOVA). The latter showed that 55% of the variables indicate a statistically significant difference. The former showed that only the Peloponesean population is well differentiated. The groups from Epirus and Macedonia differentiated between them less, compared to the Peloponesean group.