Landscape science: a Russian geographical tradition

The Russian geographical tradition of landscape science (landshaftovedenie) is analyzed with particular reference to its initiator, Lev Semenovich Berg (1876-1950). The differences between prevailing Russian and Western concepts of landscape in geography are discussed, and their common origins in German geographical thought in the late nineteenth and early twentieth centuries are delineated. It is argued that the principal differences are accounted for by a number of factors, of which Russia's own distinctive tradition in environmental science deriving from the work of V. V. Dokuchaev (1846-1903), the activities of certain key individuals (such as Berg and C. O. Sauer), and the very different social and political circumstances in different parts of the world appear to be the most significant. At the same time it is noted that neither in Russia nor in the West have geographers succeeded in specifying an agreed and unproblematic understanding of landscape, or more broadly in promoting a common geographical conception of human-environment relationships. In light of such uncertainties, the latter part of the article argues for closer international links between the variant landscape traditions in geography as an important contribution to the quest for sustainability

THERMOELECTRIC PROPERTIES OF HOT-PRESSED p-TYPE Mg2Si0.3Sn0.7 SOLID SOLUTION

It is shown that thermoelectric energy conversion which gives the possibility for utilizing a low potential heat is one of the ways for adoption of energy-saving technologies; and semiconductor materials with p-type and n-type conductivities having high thermoelectric figure of merit are necessary for operation of thermoelectric generators. The paper deals with possibility of usage of the p-Mg2Si0.3Sn0.7 solid solution (with a nanostructured modification) as a couple for the well studied thermoelectric material based on n-Mg2Si-Mg2Sn. A technological scheme for fabrication of heavily doped Mg2Si0.3Sn0.7 solid solution of p-type by hot pressing from nanopowder is developed. The given technology has made it possible to reduce duration of a homogeneous material fabrication and has improved its physical and chemical properties. The samples were made by three ways: direct fusion for polycrystals fabrication; hot pressing from microparticles; nanostructuring, i.e. hot pressing from nanoparticles. By X-ray diffraction it is shown that sizes of structural elements in the fabricated samples are about 40 nm. The probe technique is used for measurement of electric conductivity and Seebeck coefficient. The stationary absolute method is used for measurement of thermal conductivity. Thermoelectric figure of merit is defined by measured values of kinetic coefficients in the temperatures range of 77 – 800 K. It was demonstrated, that electric conductivity, Seebeck coefficient and the power factor do not depend practically on a way of solid solution preparation. Thermal conductivity of samples pressed from nanoparticles has appeared to be higher, than of samples, obtained by direct fusion; i.e. in this case nanostructuring has not led to increase of thermoelectric figure of merit. The conclusion is drawn, that polycrystalline semiconductor Mg2Si0.3Sn0.7 can be used as a p-branch for a thermoelectric generator though nanostructuring has not led to the figure of merit growth. The assumption is made, that thermoelectric figure of merit improvement can be expected at the further reduction of the nanograins size

Development of Cheaper Embryo Vitrification Device Using the Minimum Volume Method

[EN] This study was designed to compare the efficiency of the Cryotop and Calibrated plastic inoculation loop (CPIL) devices for vitrification of rabbit embryos on in vitro development and implantation rate, offspring rate at birth and embryonic and fetal losses. CPIL is a simple tool used mainly by microbiologists to retrieve an inoculum from a culture of microorganisms. In experiment 1, embryos were vitrified using a Cryotop device and a CPIL device. There were no significant differences in hatched/hatching blastocyst stage rates after 48 h of culture among the vitrified groups (62±4.7% and 62±4.9%, respectively); however, the rates were significantly lower (P<0.05) than those of the fresh group (95±3.4%). In experiment 2, vitrified embryos were transferred using laparoscopic technique. The number of implanted embryos was estimated by laparoscopy as number of implantation sites at day 14 of gestation. At birth, total offspring were recorded. Embryonic and fetal losses were calculated as the difference between implanted embryos and embryos transferred and total born at birth and implanted embryos, respectively. The rate of implantation and development to term was similar between both vitrification devices (56±7.2% and 50±6.8% for implantation rate and 40±7.1% and 35±6.5% for offspring rate at birth); but significantly lower than in the fresh group (78±6.6% for implantation rate and 70±7.2% for offspring rate at birth, P<0.05). Likewise, embryonic losses were similar between both vitrification devices (44±7.2% and 50±6.8%), but significantly higher than in the fresh group (23±6.6%, P < 0.05). However, fetal losses were similar between groups (10±4.4%, 15±4.8% and 8±4.2%, for vitrified, Cryotop or CPIL and fresh, respectively). These results indicate that the CPIL device is as effective as the Cryotop device for vitrification of rabbit embryos, but at a cost of 0.05 per device.This research was supported by the projects Spanish Research project AGL2014-53405-C2-1-P Comision Interministerial de Ciencia y Tecnologia (FMJ, JSV) and Generalitat Valenciana research program (Prometeo II 2014/036, JSV, FMJ).Marco Jiménez, F.; Jiménez Trigos, ME.; Almela-Miralles, V.; Vicente Antón, JS. (2016). Development of Cheaper Embryo Vitrification Device Using the Minimum Volume Method. PLoS ONE. 11(2):1-9. https://doi.org/10.1371/journal.pone.0148661S1911

Study of qualitative and quantitative indicators of the spermatogenesis for determination of the effectiveness of cryopreservation

Semen or spermatozoa cryopreservation (commonly called sperm banking) is a procedure to preserve sperm cells. Semen can be used successfully indefinitely after cryopreservation and might be stored successfully over 20 years. It can be used for sperm donation where the recipient wants the treatment in a different time or place, or as a means of preserving fertility for men undergoing vasectomy or treatments that may compromise their fertility, such as chemotherapy, radiation therapy or surgery. However, before the cryopreservation, it is necessary to check the parameters of the ejaculate and treat the sperm in a special container (a small in diameter plastic box with information about the patient) to increase the concentration of spermatozoa. Put the container for storage into Dewar tube. In some cases, cryopreservation might worsen the quality of the ejaculate. After freezing, the mobility and morphology of the sperm can deteriorate. Thus, it is desirable to carry out freezing in test conditions to determine the need for the frozen material. Especially when spouses plan to use additional fertilization programs, this approach should be taken into account, since cryopreservation might cause a spontaneous change in the program of intracytoplasmic vaccination of the spouse. One of the methodological problems of cryopreservation is poor quality of the ejaculate, i.e. when freezing spermatozoa, their activity and function deteriorate from the norm. This reduces the possibility of using them in the future for artificial insemination. Results of the experiment show that cryof preservation is possible only in specialized centers with the highest professional standards