Productivity of most improved major food crops showed stagnation in the past decades. As human population is projected to reach 9-10 billion by the end of the 21st century, agricultural productivity must be increased to ensure their demands. Photosynthetic capacity is the basic process underlying primary biological productivity in green plants and enhancing it might lead to increasing potential of the crop yields. Several approaches may improve the photosynthetic capacity, including integrated systems management, in order to close wide gaps between actual farmer’s and the optimum obtainable yield. Conventional and molecular genetic improvement to increase leaf net photosynthesis (P N) are viable approaches, which have been recently shown in few crops. Bioengineering the more efficient CC4 into C3 system is another ambitious approach that is currently being applied to the C3 rice crop. Two under-researched, yet old important crops native to the tropic Americas (i.e., the CC4 amaranths and the C3-CC4 intermediate cassava), have shown high potential P N, high productivity, high water use efficiency, and tolerance to heat and drought stresses. These physiological traits make them suitable for future agricultural systems, particularly in a globally warming climate. Work on crop canopy photosynthesis included that on flowering genes, which control formation and decline of the canopy photosynthetic activity, have contributed to the climate change research effort. The plant breeders need to select for higher P N to enhance the yield and crop tolerance to environmental stresses. The plant science instructors, and researchers, for various reasons, need to focus more on tropical species and to use the research, highlighted here, as an example of how to increase their yields., M. A. El-Sharkawy., and Obsahuje seznam literatury
While observational studies led to the assumption that water or moisture (W/M) is a prerequisite for diapause development, the experimental research indicates rather the opposite: usually W/M is needed as late as for the post-diapause resumption of morphogenesis. Recent examples for this type of regulation of dormancy are given: Eggs of the tettigoniid Stictophaula armata, eggs of the grasshopper Oedaleus senegalensis, adults of the bruchid Bruchidius atrolineatus, adults of the endomychid Stenotarsus subtilis (= S. rotundus). In the late diapause of the noctuid Busseola fusca and in eggs of the chrysomelid Homichloda barkeri, moisture is assumed to be the diapause terminating cue. Fall in temperature is assumed decisive for termination of pupal diapause in the saturniid Schausiella santarosensis, although the effect of intense rain after a long dry period has not yet been excluded. Effects of intense changes in environmental conditions and of gradual decrease in diapause intensity with time have often been neglected.
Very high pressure is required to generate hard faeces - 5-10 atmospheres. This is much more than can be supplied by the mechanical force from the muscular wall of the colon. Osmotic pressure (at least 200 mOsm) can generate the necessary suction forces required to consolidate faeces. The colon has a hypertonic absórbate (net above plasma - 500 mOsm) in uiuo. Fluorescence imaging of perifused rat descending colonic mucosa shows high steady state Na+ concentrations (600 mM) in the intercryptal extracellular space and low [Na + ] present in the crypt lumen. This [Na + ] distribution generates an osmotic pressure gradient across the crypt luminal wall resulting in a fluid inflow into the crypt lumen. Direct observation using confocal fluorescence microscopy of FITC dextran (mol. wt. 10 000) shows that there is concentration polarisation of the dextran in the upper 30 % of the crypt lumen. The time course and steady state distribution of concentration polarisation of fluorescent dyes within the crypt lumen permit an estimation of the fluid convection rate along the length of the crypt lumen. This is sufficient to account for the majority of fluid absorption by the colon. Observation of the suction force on agarose gels by rat descending colon in vivo shows that the colon generates up to 4 000 cm H2O suction pressure on the stiff gels, this is accompanied by a hypertonic absórbate from the gels of 800 mOsm. Disruption of the colonic musoca by bile salts reduces the suction pressure to about 40 cm H2O.
The Institute of Archaeology of Academy of Sciences of the Czech Republic in Brno organized in the days of 24.- 25.9.2012 in the town of Hodonín a colloquium "Usus aquarum - Water and Water Structures in the LIfe of the Early Middle Ages Societies of the Central Europe" within the conference series "Internationale Tagungen in Mikulčice". Since the deditors obtained for the planned proceedings of papers in the 10. volume of publication series "Internationale Tagungen in Mikulčice" only 5 papers, these papers were relocated into the journal Synopsis of researches and published here in the block following this introduciton. This is a brief report on the colloquium - its course, aim, programme, etc., Lumír Poláček., and Obsahuje seznam literatury
Water-borne transmission of the coccidium Cryptosporidium parvum Tyzzer, 1912 is frequently responsible for outbreaks of human cryptosporidiosis. One of the most important was reported in 1993 in Milwaukee in the United States, where 403,000 cases were recorded. The determination of the percentage of oocysts excystated is the first step in evaluating their viability, but it alone is not sufficient. This percentage depended on the conditions of storage and also the presence of oxidant or disinfectent agents in water. The percentage of excystation is not always related to viability. Therefore, determination of the viability of excysted sporozoites by determining their infectivity for enterocytic Caco2 cell lines in culture provides information essential for evaluating the risk of contaminated drinking water.
Voda je velmi důležitou složkou podílející se prakticky na všech důležitých vlastnostech zemědělských produktů, potravin a biologických objektů. Mezi těmito vlastnostmi hrají důležitou úlohu vlastnosti mechanické včetně vlastností viskoelastických. Tyto vlastnosti jsou ovlivňovány zejména teplotou a deformační rychlostí, v nichž voda hraje významnou "plastifikační“ úlohu. Byly vytvořeny relativně jednoduché modely pro deformaci měkkých homogenních látek a charakter teorií spojených s těmito modely je diskutován v této práci. Vliv obsahu vody je navíc strukturně a koncentračně závislý. Všechny tyto vlastnosti jsou nejlépe vyjádřeny sorpčními izotermami., Jiří Blahovec., and Obsahuje seznam literatury
To, že naši předkové zařadili vodu mezi jeden ze živlů, určitě nebyl omyl. Voda je jistě mocnou silou spoluutvářející geologickou tvář naší planety. Hýbe národy, pokud jí není dost, nebo se stává geopolitikou, pokud si vědci dovolí předpovědět růst hladiny oceánů. Přes všechnu kreativitu a představivost lidského ducha je právě voda tou neodmyslitelnou podmínkou samotné existence jakékoli formy života. Má však ještě jeden, téměř až poetický rozměr - šálí nás svou zdánlivou obyčejností. Při pohledu na zamrzlé jezero nás ani nenapadne, že je něco špatně, že "normální kapalina" při přechodu do pevné fáze svou hustotu zvýší a neútěšně klesá ke dnu. Anomálie vody se nám staly normálními a normálním se nám stalo, že je pořád neumíme uspokojivě vysvětlit. To se nám však nedávno podařilo alespoň částečně napravit., Certainly it was not a mistake, that our ancestors included water among one of the classical elements. Water is a powerful force, forming the geological face of out planet. It changes nations if there is a shortage on it, or enters geopolitics when scientists dare to predict the rise in ocean levels. Despite all the creativity and imagination of the human spirit, water is the one condition needed for the existence of any form of life. Moreover, it has another poetic dimension, where it deceives us with its apparent ordinariness. Looking at a frozen lake, it doesn‘t even occur to us that there is something wrong that when a "normal liquid" is transitioning into the solid phase its density rises, and therefore falls relenlessly to the bottom. Water anomalies have become normal to us, and in fact we still cannot explain them sufficiently. However, we have recently managed to, at least partially, correct this., Michal Duška., and Obsahuje bibliografické odkazy