Age structure and static life tables of the endangered Juniperus phoenicea L. in North Sinai Mountains, Egypt:implication for conservation

Studying the population ecology of endangered plants provides important baseline information for its monitoring and conservation.Juniperus phoenicea L.is an endangered species in arid ecosystems in Africa and the Middle East.The static life tables,survival curve and age structure of J.phoenicea populations from two mountains in North Sinai,Egypt(Gabal(G.)El-Halal and G.El-Maghara)were investigated.In each mountain,fifteen plots were selected,and field measurements such as stand density,tree height,and crown diameter were conducted.Moreover,44 trees were cored and crossdated according to standard dendrochronological procedures.The results showed that the tree ages ranged from 50 to 262 years at G.El-Halal and 96 to431 years at G.El-Maghara.Mature J.phoenicea individuals dominated the study area,with only a few individuals being younger than 100 years.Moreover,seedling recruitment was extremely limited.Since the studied J.phoenicea populations showed high mortality rates among both old and young individuals,there is an imminent need for establishing a conservation program to prevent its extinction in the future.Therefore,management and conservation efforts should be made to minimize human disturbance and protect the relic habitats of this endangered species at its southern distribution limits in Africa.

Influence of Superplasticizers on Early Age Drying Shrinkage of Cement Paste with the Same Consistency

The influence of superplasticizer（SP） on the early age drying shrinkage of cement paste with the same consistency was investigated. To conduct the test, which lasted for 72 hours, three paste mixtures were used for comparison. The 72 hours early age drying shrinkage staring from the initial setting time was measured by a clock gauge. The pore size distribution was measured by Mercury Intrusion Method. The surface tension of capillary simulation liquid and mass loss of paste were also measured. The experimental results showed that the addition of SP increased the early drying shrinkage greatly. The ratios of water evaporation and the total free water in mixtures added with SPs showed great differences. SPs fined the capillary pores of paste, and the volume of pore with diameter within 50 nm was well consistent with shrinkage rate. The addition of SPs did not raise the capillary liquid surface tension. It showed that with the volume of pore with diameter within 50 nm and the ratio of water evaporation and the total free water a tolerable shrinkage result of paste added with SP could be predicted, and the elastic modulus could have an influence on the early shrinkage. These results have never been proposed before.

Perioperative chemotherapy for advanced gastric cancer - results from a tertiary-care hospital in Germany

BACKGROUND Neoadjuvant/perioperative chemotherapy is the recommended treatment for advanced stages of gastric cancer(>T2,N+)before tumour resection in many European guidelines.However,there is no consensus as to whether perioperative chemotherapy is as effective in distal as in proximal tumours,in addition to a relevant uncertainty concerning appropriate treatment modalities for elderly patients.AIM To investigate the role of perioperative chemotherapy in advanced gastric cancer in patients from a German tertiary clinic with respect to efficacy,localisation,and age.METHODS We performed a retrospective analysis of 158 patients from our clinic with adenocarcinoma of the stomach or the gastroesophageal junction who underwent resection between 2008 and 2016.The data were evaluated particularly in relation to patient age,tumour site,and perioperative therapy.RESULTS Administration of perioperative chemotherapy did not lead to a significant survival advantage in our study population.The 5-year survival rates were 40%for patients who received perioperative chemotherapy and 29%for the group without perioperative chemotherapy(P=0.125).Our patients were on average distinctly older than patients in most of the published randomised controlled trials.Patients elder than 75 years received perioperative chemotherapy far less frequently.Patients with a proximal tumour received perioperative chemotherapy much more often.CONCLUSION This analysis reconfirms our previous data concerning the effectiveness of perioperative chemotherapy for advanced gastric cancer.There is reasonable doubt that the quality of the existing randomized controlled trials is sufficient to generally justify perioperative chemotherapy in patients with advanced gastric cancer independent of tumour localization or age.

Unraveling one billion years of geological evolution of the southeastern Amazonia Craton from detrital zircon analyses

Despite representing one of the largest cratons on Earth,the early geological evolution of the Amazonia Craton remains poorly known due to relatively poor exposure and because younger metamorphic and tectonic events have obscured initial information.In this study,we investigated the sedimentary archives of the Carajás Basin to unravel the early geological evolution of the southeastern Amazonia Craton.The Carajás Basin contains sedimentary rocks that were deposited throughout a long period spanning more than one billion years from the Mesoarchean to the Paleoproterozoic.The oldest archives preserved in this basin consist of a few ca.3.6 Ga detrital zircon grains showing that the geological roots of the Amazonia Craton were already formed by the Eoarchean.During the Paleoarchean or the early Mesoarchean(<3.1 Ga),the Carajás Basin was large and rigid enough to sustain the formation and preservation of the Rio Novo Group greenstone belt.Later,during the Neoarchean,at ca.2.7 Ga,the southeastern Amazonia Craton witnessed the emplacement of the Parauapebas Large Igneous Province(LIP)that probably covered a large part of the craton and was associated with the deposition of some of the world largest iron formations.The emplacement of this LIP immediately preceded a period of continental extension that formed a rift infilled first by iron formations followed by terrigenous sediments.This major change of sedimentary regime might have been controlled by the regional tectonic evolution of the Amazonia Craton and its emergence above sea-level.During the Paleoproterozoic,at ca.2.1 Ga,the Rio Fresco Group,consisting of terrigenous sediments from the interior of the Amazonia Craton,was deposited in the Carajás Basin.At that time,the Amazonian lithosphere could have either underwent thermal subsidence forming a large intracratonic basin or could have been deformed by long wavelength flexures that induced the formation of basins and swells throughout the craton under the influence of the growing Transamazonian mountain belt.

Molecular analysis of bacterial community in the tap water with different water ages of a drinking water distribution system

Bacterial community in the drinking water distribution system （DWDS） was regulated by multiple environmental factors, many of which varied as a function of water age. In this study, four water samples with different water ages, including finished water （FW, 0 d） and tap water （TW） [TWI （1 d）, TW2（2 d） and TW3（3 d）], were collected along with the mains of a practical DWDS, and the bacterial community was investigated by high-throughput sequencing technique. Results indicated that the residual chlorine declined with the increase of water age, accompanied by the increase of dissolved organic matter, total bacteria counts and bacterial diversity （Shannon）. For bacterial community composition, although Proteobacteria phylum （84.12%-97.6%） and Alphaproteobacteria class （67.42c/,~93.09%） kept dominate, an evident regular was observed at the order level. In detail, the relative abundance of most of other residual orders increased with different degrees from the start to the end of the DWDS, while a downward trend was uniquely observed in terms of Rhizobiales, who was inferred to be chlorine-resistant and be helpful for inhibiting pipes corrosion. Moreover, some OTUs were found to be closely related with species possessing pathogenicity and chlorine-resistant ability, so it was recommended that the use of agents other than chlorine or agents that can act synergically with chlorine should be developed for drinking water disinfection. This paper revealed bacterial community variations along the mains of the DWDS and the result was helpful for understanding bacterial ecology in the DWDS.

Aging and Migration： Micro and Macro Evidence from China

Post-reform China has been experiencing two major demographic changes： an increasingly aging population and an extraordinary surge of rural-urban migrants. The question we ask is： are these two demographic changes related？ If yes, then, how？ The standard view in the migration literature is that the older the migrant, the lower the likelihood of migration. This paper proposes a simple theory of temporary migration for unskilled labor to fit the context of China Motivated by our model, we then use both cross-sectional micro data and panel macro data to examine the potential impacts of aging on migration. We find that shifts in China＇s age distribution have generated significant changes in the country＇s migration patterns： migration will shift to closer provinces （probably switching from interprovincial migration to intra-provincial migration） and will concentrate to a few destination provinces.