植物叶片厚度日变化规律数学模型的研究

为了实现对植物生长状态的精确控制,本文对植物的可观测性进行了研究．首先, 运用工业计量的先进方法研制了适合植物叶片精密测量的仪器,用该仪器对二种花卉植物进行了 6个月以上的监测,获得了所监测植物的短周期变化规律,从而证实了植物叶片厚度的“可测量性”．该变化规律的峰值发生在中午,成为研究的重点．对峰值期建立了具有微分形式的数学模型,该模型可为后续的控制研究提供重要的理论依据．     

Oldest art or symbolic expressions in North America? Pleistocene modified bones and a human remain at Sima de las Golondrinas cave,Zacatecas, Mexico

The discovery of Pleistocene human presence at Chiquihuite Cave (state of Zacatecas, Mexico) dating to, or even before, the Last Glacial Maximum (LGM, over 18,000 years ago), prompted the search for another cave site in the same region, where the implications of Chiquihuite could be tested and corroborated in a second context. In January 2020, we started work at Sima de las Golondrinas (“Chasm of Swallows”), a cavern in the Zuloaga mountains. Excavation unit X-20 focused on an older profile left behind by unknown early-20th-century explorers. Previous radiocarbon dating of three charcoal-rich deposits had indicated the stratigraphy contained deposits ranging in age from the Terminal LGM to the Middle Holocene. The short-timed excavation revealed the stratigraphic sequence had been slowly deposited in an aquatic environment, when the cave was partly inundated for thousands of years, until the Holocene. Preliminary palynological studies confirmed the presence of water and nearby lakes, matching the paleoenvironmental reconstructions from Chiquihuite, 100 km away. Excavation X-20 yielded no lithic tools or stone raw materials, but an abundance of zoo-archaeological materials, yet without the presence of traditional megafauna. Some specimens present human modifications in the form of butchery-related cut marks, but also engravings possibly related to early symbolic behaviors. Here, we present a selection of eight bones of elevated archaeological importance. One of them is an ischium bone belonging to a young Homo sp. individual, dating to the Early Holocene. The other seven are modified bones coming from layers dating between the Terminal LGM and Younger Dryas. They belonged to white-tailed deer (Odocoileus virginianus), mountain bighorn sheep (Ovis canadensis), and American pronghorn (Antilocapra americana). The assemblage includes four human-modified animal phalanges, with symbolic expression substrates. Two of them were found in levels older than 16,000 years, and may well represent some of the oldest forms of art in the Americas.     

How do babies know their friends and foes?

The study of infant social cognition is the study of how human infants acquire information about people. By examining infants’ sensory abilities and the stimulus characteristics of people, research can determine what information is available to infants from their social world. We can then consider what social environments are appropriate for infants of different ages. This paper examines the sociocognitive competencies of human infants during the first 6 months of their lives and asks how these competencies are functional in the daily social ecology of the human infant. Select examples of research with other species are used to illustrate how the adaptive significance of sociocognitive abilities could be more fruitfully explored in studies of human infancy. Lonnie R. Sherrod is Vice President for Program at the William T. Grant Foundation. Formerly, he was Assistant Dean at the Graduate Faculty of the New School for Social Research and before that, Staff Associate at the Social Science Research Council. He received a Ph.D. in Developmental Psychology from Yale University in 1978, an M.A. in Biology from the University of Rochester in 1974; and a B.A. in Zoology and Psychology from Duke University in 1972. He has taught at New York University and the New School and has published numerous articles and edited volumes on infant social cognition, on adolescence, and on child development from a life-span and biosocial perspective. Examples includeInfant Social Cognition (1981), edited with Michael Lamb;The Life Course and Human Development: Multidisciplinary Perspectives (1986), edited with Aage B. Sorensen and Franz E. Weinert; and “Changes in Children’s Social Lives and the Development of Social Understanding” authored with Judith Dunn (1988), in E.M. Hetherington, M. Perlmutter, and R. Lerner (eds).,Child Development in Life-Span Perspective.     

Functional Exploration of Chaperonin (HSP60/10) Family Genes and their Abiotic Stress-induced Expression Patterns in Sorghum bicolor

Background Sorghum, the C4 dry-land cereal, important for food, fodder, feed and fuel, is a model crop for abiotic stress tolerance with smaller genome size, genetic diversity, and bio-energy traits. The heat shock proteins/chaperonin 60s (HSP60/Cpn60s) assist the plastid proteins, and participate in the folding and aggregation of proteins. However, the functions of HSP60s in abiotic stress tolerance in Sorghum remain unclear.MethodsGenome-wide screening and in silico characterization of SbHSP60s were carried out along with tissue and stress-specific expression analysis.ResultsA total of 36 HSP60 genes were identified in Sorghum bicolor. They were subdivided into 2 groups, the HSP60 and HSP10 co-chaperonins encoded by 30 and 6 genes, respectively. The genes are distributed on all the chromosomes, chromosome 1 being the hot spot with 9 genes. All the HSP60s were found hydrophilic and highly unstable. The HSP60 genes showed a large number of introns, the majority of them with more than 10. Among the 12 paralogs, only 1 was tandem and the remaining 11 segmental, indicating their role in the expansion of SbHSP60s. Majority of the SbHSP60 genes expressed uniformly in leaf while a moderate expression was observed in the root tissues, with the highest expression displayed by SbHSP60-1. From expression analysis, SbHSP60-3 for drought, SbHSP60-9 for salt, SbHSP60-9 and 24 for heat and SbHSP60-3, 9 and SbHSP10-2 have been found implicated for cold stress tolerance and appeared as the key regulatory genes.ConclusionThis work paves the way for the utilization of chaperonin family genes for achieving abiotic stress tolerance in plants.