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Excess illumination damages the photosynthetic apparatus with severe implications with regard to plant productivity. Unlike model organisms, the growth of Chlorella ohadii, isolated from desert soil crust, remains unchanged and photosynthetic O2 evolution increases, even when exposed to irradiation twice that of maximal sunlight. Spectroscopic, biochemical and molecular approaches were applied to uncover the mechanisms involved. D1 protein in photosystem II (PSII) is barely degraded, even when exposed to antibiotics that prevent its replenishment. Measurements of various PSII parameters indicate that this complex functions differently from that in model organisms and suggest that C. ohadii activates a nonradiative electron recombination route which minimizes singlet oxygen formation and the resulting photoinhibition. The light-harvesting antenna is very small and carotene composition is hardly affected by excess illumination. Instead of succumbing to photodamage, C. ohadii activates additional means to dissipate excess light energy. It undergoes major structural, compositional and physiological changes, leading to a large rise in photosynthetic rate, lipids and carbohydrate content and inorganic carbon cycling. The ability of C. ohadii to avoid photodamage relies on a modified function of PSII and the dissipation of excess reductants downstream of the photosynthetic reaction centers. The biotechnological potential as a gene source for crop plant improvement is self-evident.

Abstract Biological soil crusts (BSCs) are found in drylands, cover ∼12% of the Earth's surface in arid and semi-arid lands and their destruction is considered an important promoter of desertification. These crusts are formed by the adhesion of soil particles to polysaccharides excreted mostly by filamentous cyanobacteria, which are the pioneers and main primary producers in BSCs. Desert BSCs survive in one of the harshest environments on Earth, and are exposed to daily fluctuations of extreme conditions. The cyanobacteria inhabiting these habitats must precisely read the changing conditions and predict, for example, the forthcoming desiccation. Moreover, they evolved a comprehensive regulation of multiple adaptation strategies to enhance their stress tolerance. Here, we focus on what distinguishes cyanobacteria able to revive after dehydration from those that cannot. While important progress has been made in our understanding of physiological, biochemical and omics aspects, clarification of the sensing, signal transduction and responses enabling desiccation tolerance are just emerging. We plot the trajectory of current research and open questions ranging from general strategies and regulatory adaptations in the hydration/desiccation cycle, to recent advances in our understanding of photosynthetic adaptation. The acquired knowledge provides new insights to mitigate desertification and improve plant productivity under drought conditions. Cyanobacteria inhabiting desert biological soil crusts, one of the harshest environments on Earth, have evolved mechanisms for predicting, sensing, signal transduction and cellular responses enabling their vegetative cells to cope with daily hydration/desiccation cycles and extreme conditions.

Cyanobacteria occur worldwide but play an important role in the formation and primary activity of biological soil crusts (BSCs) in arid and semi-arid ecosystems. The cyanobacterial diversity in BSCs of the northwest Negev desert of Israel was surveyed at three fixed sampling stations situated along a precipitation gradient in the years 2010 to 2012. The three stations also are characterized by marked differences in soil features such as soil carbon, nitrogen, or electrical conductivity. The cyanobacterial biodiversity was analyzed by sequencing inserts of clone libraries harboring partial 16S rRNA gene sequences obtained with cyanobacteria-specific primers. Filamentous, non-diazotrophic strains (subsection III), particularly Microcoleuslike, dominated the cyanobacterial community (30 % proportion) in all years. Specific cyanobacterial groups showed increased (e.g., Chroococcidiopsis, Leptolyngbya, and Nostoc strains) or decreased (e.g., unicellular strains belonging to the subsection I and Scytonema strains) abundances with declining water availability at the most arid, southern station, whereas many cyanobacterial strains were frequently found in the soils of all three stations. The cyanobacterial diversity at the three sampling stations appears dependent on the available precipitation, whereas the differences in soil chemistry were of lower importance.

Biological soil crusts (BSCs) fulfil numerous ecological functions in arid and semiarid areas. Cyanobacteria are important BSC organisms, which are responsible for carbon fixation, N2 fixation and binding of soil via extracellular polysaccharides. The cyanobacterial populations were characterised in different sampling plots established in three experimental stations along a rainfall gradient within NW Negev Desert, Israel. Cyanobacterial crust thickness and osmolyte accumulation therein decreased in plots with lower moisture. The cyanobacterial population structure also changed in different plots. We observed an increase of subsection III cyanobacteria such as Microcoleus spp. and Leptolyngbya spp. and a decreasing proportion of strains belonging to subsections I and IV in drier areas on the rainfall gradient. This population shift was also observed in the sampling plots, which were situated at various relief positions within the sand dune experimental sites. We also characterised the cyanobacterial populations within mechanically disturbed plots. After 4 years, they reached between 80% and 50% of the control populations in the northernmost and southern stations, respectively. Our results suggest that the cyanobacterial population is sensitive not only to macroscale factors but may also be subject to local climate variations and that 4 years was insufficient for complete recovery of the cyanobacterial population.

We describe a GIS-based real-time system for emergency response and management of air pollution accidents in an urban area. The system architecture emphasises the integration of meteorological, chemical and GIS data, dispersion modeling, decision-making and geo-spatial visualization. The threat zones, unsafe areas and safe traffic routes are obtained using an improved Gaussian plume model with a decision-making module and then exported to the Google Earth browser via “kml” file format. Several simulation scenarios were conducted and verified for notable industrial sites in Montenegro using recorded meteorological data. The results demonstrate that emergency response authorities can use the proposed methodology and system as a cost effective and accurate support tool in case of industrial or deliberate air pollution incidents.

The development of a simple and low-cost portable weighing microlysimeter that makes use of a load cell for automated recording and for studying daily dew formation, rate of accumulation, and subsequent evaporation in arid or semiarid regions during rainless seasons is presented. The sampling cup is 3.5 cm deep, with the load cell itself situated at 20-cm depth to minimize temperature effects. The device was tested in a sand dune experimental station situated near Nizzana, northwest Negev Desert, Israel, during which extensive micrometeorological measurements were collected. One microlysimeter was placed in a playa and a second was installed on the stabilized midslope of an adjacent linear sand dune. To assess the performance of the load cell microlysimeters (LCM), one pair of manual microlysimeters was installed next to each LCM. A third pair was installed at a point between the LCMs and a fourth pair above the midslope LCM. Sixteen overnight measurements were carried out within a 6-week period. The LCM could measure dew with an error of ±0.02 mm. The daily dew variation in the samples during the 16 overnight measurements ranged up to 0.2 mm on stable dune slopes but up to 0.4 mm on the playa. This difference is attributed to the playa’s high silt and clay content and salinity. Dew formation and accumulation were found to occur long before the soil-surface temperature reached the dewpoint temperature of the air. The cost of building this microlysimeter, excluding labor, is about $175 (U.S.).

Sheikh Raed Salah, head of the movement's northern branch, has been quoted in press reports as calling the Torah and Talmud \"heretical,\" evil works that no Muslim can tolerate. He reached this conclusion after surveying \"Jewish religious literature\" in the space of a few hours. His tirade against the Bible was, of course, a pretext for vilifying Judaism and denying the Jews any historical connection with Jerusalem, especially the Temple Mount. Sir, - I am saddened to see Israel looking more and more like a country for anyone but the Jewish people. Here we have the non- Jews complaining about the dig near the Wailing Wall. When Muslims destroy all the stuff they dig up around you to make room for their place of worship, you do not hear such an outcry. Muslims are destroying anything that is not related to their religion, but the Jews have been very, very careful to preserve everything they dig up. In 2004 I co-supervised Alon Gross in developing a portable fog and dew collector for camping and hiking for his final year design project at the Teachers College of Technology, Tel Aviv. His work won a 5,000-euro first prize in the 2004 Saint-Etienne Metropole Design international competition, held in France, on the theme of \"Travel in a Sustainable World.\" His portable dew collector was in the form of an inverted pyramid.

Sir, - Re \"Birthright slams Masa for wasteful duplication of efforts\" (July 5): I was surprised to see a gulf growing between Taglit-birthright and Masa. The impression one gets from the current dispute is that Taglit-birthright views Masa as an interloper in the field of bringing young Jews to Israel. The Alisa Flatow Memorial Fund has been providing scholarship assistance to college-age men and women seeking to study Judaism in Israel since 1996. Named in memory of my daughter who was murdered by Palestinian Islamic Jihad while she was a student in Israel, the fund has helped about 100 students over the past 10 years to attend yeshivot, seminaries and other institutions throughout Israel. Let's face it, Taglit-birthright, Masa, and even a small program such as Alisa's have room to operate simultaneously and work toward their common goal - creating a generation of Jews who know who they are, and imparting an appreciation of the State of Israel and of what Judaism is all about.

OF ALL the Hasmonean rulers, Antigonus produced the most impressive coins. Prof. Ya'acov Meshorer of the Israel Museum describes the menora coin in his book, Ancient Jewish Coinage, as one of the most outstanding pieces of Jewish coinage ever struck. One must realize that most of the menoras depicted in ancient Jewish art, whether on artefacts, such as glass, pottery or gems, or as pieces of architecture, or in mosaics of ancient synagogues, date from the later Roman and Byzantine periods (200-636 CE). The original menoras of the Temple destroyed in 70 CE could not have been seen by these artists. Accordingly, this coin represents one of the few designs prepared by an artist who may actually have based it on a prototype seen in the Temple. Over the generations, the menora has become a prominent symbol in Jewish art. Though the Michelin company may inadvertently have taken Israel off the map, one British geographer is certainly trying to place Israel right back onto it - and with a vengeance. A recent issue of the academic periodical, GeoJournal (vol. 19/2, pp. 99-111), contains an article by Dr. G. Rowley of the Geography Department of the University of Sheffield, England. It is entitled, \"Developing perspectives upon the areal extent of Israel: An outline evaluation.\"