An RNA gene expressed during cortical development evolved rapidly in humans

The developmental and evolutionary mechanisms behind the emergence of human-specific brain features remain largely unknown. However, the recent ability to compare our genome to that of our closest relative, the chimpanzee, provides new avenues to link genetic and phenotypic changes in the evolution of the human brain. We devised a ranking of regions in the human genome that show significant evolutionary acceleration. Here we report that the most dramatic of these 'human accelerated regions', HAR1, is part of a novel RNA gene (HAR1F) that is expressed specifically in Cajal-Retzius neurons in the developing human neocortex from 7 to 19 gestational weeks, a crucial period for cortical neuron specification and migration. HAR1F is co-expressed with reelin, a product of Cajal-Retzius neurons that is of fundamental importance in specifying the six-layer structure of the human cortex. HAR1 and the other human accelerated regions provide new candidates in the search for uniquely human biology.     

Is a pyrene-like molecular ion the cause of the 4,430-angstroms diffuse interstellar absorption band?

The diffuse interstellar bands (DIBs), ubiquitous absorption features in astronomical spectra, have been known since early this century and now number more than a hundred. Ranging from 4,400 angstroms to the near infrared, they differ markedly in depth, width and shape, making the concept of a single carrier unlikely. Whether they are due to gas or grains is not settled, but recent results suggest that the DIB carriers are quite separate from the grains that cause visual extinction. Among molecular candidates the polycyclic aromatic hydrocarbons (PAHs) have been proposed as the possible carriers of some of the DIBs, and we present here laboratory measurements of the optical spectrum of the pyrene cation C16H10+ in neon and argon matrices. The strongest absorption feature falls at 4,435 +/- 5 angstroms in the argon matrix and 4,395 +/- 5 angstroms in the neon matrix, both close to the strong 4,430-angstroms DIB. If this or a related pyrene-like species is responsible for this particular band, it must account for 0.2% of all cosmic carbon. The ion also shows an intense but puzzling broad continuum, extending from the ultraviolet to the visible, similar to what is seen in the naphthalene cation and perhaps therefore a common feature of all PAH cations. This may provide an explanation of how PAHs convert a large fraction of interstellar radiation from ultraviolet and visible wavelengths down to the infrared.     

How New Individuals Behave in a Heterogeneous Community: A Computational Approach to Norm Assimilation Using Agent-Based Systems

Heterogeneous community entails a number of social groups that adopt similar/different social norms. In such community, new individuals who join a new social group should be able to decide with which group they could assimilate based on their capabilities/values/manners. Otherwise, they would be penalized by other members in the group for violating some norms which they cannot comply.Using this approach, software agents would have better reasoning in simulating human society. In this paper, the authors propose a norms assimilation theory, in which a new agent attempts to assimilate with a social group's norms. This theory builds an approach to norm assimilation, analyzes the cases for an agent to decide to assimilate with a social group and develops a mathematical model to measure the assimilation cost and the agent's ability. The approach is developed based on the agent's internal belief about its ability and desire, and its external belief about the cost of assimilating with a number of social groups. The significance of this research is two-fold. Firstly, the study paves the way to future design of intelligent systems, i.e., software agents or robots, to closely mimic human social interactions.Secondly, the norm assimilation using agent-based system could be potentially utilized to simulate some social issues such as immigrants, new students, expatriate etc. The experiments that have been conducted demonstrate that an agent in the domain is able to calculate the assimilation cost and decide which social group to join.     

Zinc sulphate induces sterility in the cotton leafwormSpodoptera littoralis boisduval

Zusammenfassung Eine subletale Konzentration von 0,3% Zinksulfat im Larven-Nährmedium der BaumwolleuleSpodoptera littoralis ergibt morphologisch und im Verhalten normale Falter, die jedoch vollkommen steril sind und zudem eine stark reduzierte Fekundität aufweisen.

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I am indebted to Mrs.El-Sharaby for her help during this work.     

Giberellic acid andβ-sitosterol as sterilants of the cotton leaf wormSpodoptera littoralis boisduval

Zusammenfassung Wird Gibberellinsäure und Sitosterol der Larven-Diät vonSpodoptera littoralis zugegeben, so kommt es zu deutlicher Sterilität bei den ausgebrüteten Motten und zu einer Beeinflussung der Dauer ihrer Entwicklungsphase.     

Evidence of phagostimulants in cotton leaves eliciting feeding ofSpodoptera littoralis bois

Zusammenfassung Baumwollblätter enthalten mindestens eine volatile und eine nicht volatile (unverseifbare) lipophile Komponente. Diese wirken auf Larven vonSpodoptera littoralis attraktiv und stimulieren das Fressen.     

Engraftment of connexin 43-expressing cells prevents post-infarct arrhythmia

Ventricular tachyarrhythmias are the main cause of sudden death in patients after myocardial infarction. Here we show that transplantation of embryonic cardiomyocytes (eCMs) in myocardial infarcts protects against the induction of ventricular tachycardia (VT) in mice. Engraftment of eCMs, but not skeletal myoblasts (SMs), bone marrow cells or cardiac myofibroblasts, markedly decreased the incidence of VT induced by in vivo pacing. eCM engraftment results in improved electrical coupling between the surrounding myocardium and the infarct region, and Ca2+ signals from engrafted eCMs expressing a genetically encoded Ca2+ indicator could be entrained during sinoatrial cardiac activation in vivo. eCM grafts also increased conduction velocity and decreased the incidence of conduction block within the infarct. VT protection is critically dependent on expression of the gap-junction protein connexin 43 (Cx43; also known as Gja1): SMs genetically engineered to express Cx43 conferred a similar protection to that of eCMs against induced VT. Thus, engraftment of Cx43-expressing myocytes has the potential to reduce life-threatening post-infarct arrhythmias through the augmentation of intercellular coupling, suggesting autologous strategies for cardiac cell-based therapy.