Group a streptococcal serotypes isolated from healthy schoolchildren in iran

Serotypes of group A streptococci are still a major cause of pharyngitis and some post-infectious sequelae such as rheumatic fever. As part of the worldwide effort to clarify the epidemiological pattern of group A streptococci in different countries, the present study was conducted to assess the prevalence of Streptococcus pyogenes serotypes in Iran. A total of 1588 throat swabs were taken from healthy school children in the city of Gorgan during February and March 1999. Of those isolates, 175 resulted positive for group A streptococci. The distribution pattern was similar for girls and boys, with 10.8 and 11.2, respectively. Urban school children showed a higher rate of colonization compared to those in rural areas. Serotyping was performed on 65 of the positive isolates using standard techniques, and only 21 (32) were M-type isolates. Their profiles fell into four types with M1 predominating, which could reflect the presence of rheumatic fever in the region. However, when isolates were challenged for T-antigen types, nearly all were positive (94). The pattern of T types was diverse (18 types), with the most common T types being T1 (26), TB3264 (15), TB\1-19 & B\25\1-19 (9.2) and T2 & 2\28 (7.7). When isolates were tested for opacity factor, only 23 (35) were positive while 34 (52) responded to the serum opacity reaction test. Although the number of isolates in this study was not sufficient to make any epidemiological conclusions, the scarcity of serotyping studies in Iran could render these data useful for future attempts to develop a streptococcal vaccine

A review of size and geometrical factors influencing resonant frequencies in metamaterials

Although metamaterials and so-called left-handed media have originated from theoretical considerations, it is only by their practical fabrication and the measurement of their properties that they have gained credibility and can fulfil the potential of their predicted properties. In this review we consider some of the more generally applicable fabrication methods and changes in geometry as they have progressed, exhibiting resonant frequencies ranging from radio waves to the visible optical region

Corinth Excavations Archaeological Manual

“The publication of the Corinth Excavation Manual offers us a unique view into real-life archaeological practice on one of the most important Classical sites in the Mediterranean.” Adam Rabinowitz, Associate Professor and Assistant Director, Institute of Classical Archaeology, University of Texas, Austin The Corinth Excavations Archaeological Manual is the first major field manual published from an American excavation in Greece and among a very small number of manuals published from the Eastern Mediterranean in the last generation. The appearance of this book is timely, however, as there is a growing interest in field methods and the history of excavation practices throughout the discipline of archaeology. Moreover, Corinth Excavations has long held a special place in American archaeology in Greece as the primary training excavation for graduate students associated with the American School of Classical Studies at Athens. As a result, the field manual has had a particular influence among American excavators and projects in Greece, among Mediterranean archaeologists, and in archaeology classrooms. Published as a technical field manual, an archival document, and a key statement of practice from a major excavation, the Corinth Excavations Archaeological Manual presents a guide for daily procedures at the Corinth Excavations, a complete record of documentation forms used in the field, and a practical glimpse into the functioning of a complex, major, project. The manual is a landmark text appropriate for the university student, the scholar of methodology, and the working field archaeologist. “The Corinth manual has grown over the years into a comprehensive and authoritative guide to open-area, stratigraphic excavation, covering everything from excavation of pits, wells, and robbing trenches to the removal of deposits to inventorying objects in the museum. ” David Pettegrew, Associate Professor, Messiah College and author of The Isthmus of Corinth (2016). All of the authors have worked on the excavations at Corinth in various capacities. This manual was developed under the directorship of Dr. Guy Sanders by former field directors Alicia Carter Johnson and Dr. Sarah James. Additional contributions come from past and present Corinth staff including assistant director Dr. Ioulia Tzonou-Herbst, architect James Herbst, conservator Nicol Anastasatou, and archaeologist Katerina Ragkou. The authors would also like to recognize the contributions of the many students from the American School of Classical Studies at Athens who offered valuable feedback on earlier versions of this manual over the past 10 years.https://commons.und.edu/press-books/1005/thumbnail.jp

Crop and Soil Productivity Response to Corn Residue Removal: A Literature Review

Society is facing three related issues: over-reliance on imported fuel, increasing levels of greenhouse gases in the atmosphere, and producing sufficient food for a growing world population. The U.S. Department of Energy and private enterprise are developing technology necessary to use high-cellulose feedstock, such as crop residues, for ethanol production. Corn (Zea mays L.) residue can provide about 1.7 times more C than barley (Hordeum vulgare L.), oat (Avena sativa L.), sorghum [Sorghum bicolor (L.) Moench], soybean [Glycine max L.) Merr.], sunflower (Helianthus annuus L.), and wheat (Triticum aestivum L.) residues based on production levels. Removal of crop residue from the field must be balanced against impacting the environment (soil erosion), maintaining soil organic matter levels, and pre- serving or enhancing productivity. Our objective is to summarize published works for potential impacts of wide-scale, corn stover collection on corn production capacity in Corn Belt soils. We address the issue crop yield (sustainability) and related soil processes directly. However, scarcity of data requires us to deal with the issue of greenhouse gases indirectly and by inference. All ramifications of new management practices and crop uses must be explored and evaluated fully before industry is established. Our conclusion is that within limits, corn stover can be harvested for ethanol production to provide a renewable, domestic source of energy that reduces greenhouse gases. Recommendation for removal rates will vary based on regional yield, climatic conditions, and cultural practices. Agronomists are challenged to develop a procedure (tool) for recommending maximum permissible removal rates that ensure sustained soil productivity

Mid-Miocene cooling and the extinction of tundra in continental Antarctica

A major obstacle in understanding the evolution of Cenozoic climate has been the lack of well dated terrestrial evidence from high-latitude, glaciated regions. Here, we report the discovery of exceptionally well preserved fossils of lacustrine and terrestrial organisms from the McMurdo Dry Valleys sector of the Transantarctic Mountains for which we have established a precise radiometric chronology. The fossils, which include diatoms, palynomorphs, mosses, ostracodes, and insects, represent the last vestige of a tundra community that inhabited the mountains before stepped cooling that first brought a full polar climate to Antarctica. Paleoecological analyses, 40Ar/39Ar analyses of associated ash fall, and climate inferences from glaciological modeling together suggest that mean summer temperatures in the region cooled by at least 8°C between 14.07 ± 0.05 Ma and 13.85 ± 0.03 Ma. These results provide novel constraints for the timing and amplitude of middle-Miocene cooling in Antarctica and reveal the ecological legacy of this global climate transition