Observations of Extremely Cool Stars

As one part of a program of infrared astronomy carried on at the California Institute of Technology, a survey of the sky in two infrared spectral ranges, 0.68-0.92 μand 2.01- 2.41 μ, is being carried out. The motivation for such a survey is to obtain an unbiased census of objects that emit in the 2.0-2.5-μ atmospheric window; this will, of course, include many ordinary stars, but it might also reveal many potentially interesting objects that would not be included in an a priori selection of objects to be measured. In fact, a number of strikingly red stars have already been found. Since most of these "superred" stars occur in the Milky Way, interstellar reddening may be of some consequence; but in at least a few cases the stars seem to be intrinsically extremely red. These preliminary results seem of sufficient interest to merit brief description at this time

Collective and single cell behavior in epithelial contact inhibition

Control of cell proliferation is a fundamental aspect of tissue physiology central to morphogenesis, wound healing and cancer. Although many of the molecular genetic factors are now known, the system level regulation of growth is still poorly understood. A simple form of inhibition of cell proliferation is encountered in vitro in normally differentiating epithelial cell cultures and is known as "contact inhibition". The study presented here provides a quantitative characterization of contact inhibition dynamics on tissue-wide and single cell levels. Using long-term tracking of cultured MDCK cells we demonstrate that inhibition of cell division in a confluent monolayer follows inhibition of cell motility and sets in when mechanical constraint on local expansion causes divisions to reduce cell area. We quantify cell motility and cell cycle statistics in the low density confluent regime and their change across the transition to epithelial morphology which occurs with increasing cell density. We then study the dynamics of cell area distribution arising through reductive division, determine the average mitotic rate as a function of cell size and demonstrate that complete arrest of mitosis occurs when cell area falls below a critical value. We also present a simple computational model of growth mechanics which captures all aspects of the observed behavior. Our measurements and analysis show that contact inhibition is a consequence of mechanical interaction and constraint rather than interfacial contact alone, and define quantitative phenotypes that can guide future studies of molecular mechanisms underlying contact inhibition

The Military Rule in Ecuador: Policies and Politics of Authoritarian Rule

It should be borne in mind that this study is part of a collective undertaking that examines military institutions under conservative authoritarian rule. Its preoccupations have included the impact of the military on economic policy and regime performance; military linkages with civilian interest groups; and the functioning of the military power structure. For organizational convenience, most of this paper will be devoted to two major sections. The first will focus primarily on policy, with attention to decision making and regime performance. The second will examine more directly issues of politics, embracing the place of the military in society and the evolution of ties with major interest groups. Before moving into these discussions, however, further background is appropriate. Certainly the institutional evolution of the Ecuadorean military prior to the 1970s is mandatory. Moreover, at least a few words about the significance and implications of regimes may be in order

Genetic imaging of the association of oxytocin receptor gene (OXTR) polymorphisms with positive maternal parenting

Background: Well-validated models of maternal behavior in small-brain mammals posit a central role of oxytocin in parenting, by reducing stress and enhancing the reward value of social interactions with offspring. In contrast, human studies are only beginning to gain insights into how oxytocin modulates maternal behavior and affiliation. Methods: To explore associations between oxytocin receptor genes and maternal parenting behavior in humans, we conducted a genetic imaging study of women selected to exhibit a wide range of observed parenting when their children were 4-6 years old. Results: In response to child stimuli during functional magnetic resonance imaging (fMRI), hemodynamic responses in brain regions that mediate affect, reward, and social behavior were significantly correlated with observed positive parenting. Furthermore, single nucleotide polymorphisms (SNPs) (rs53576 and rs1042778) in the gene encoding the oxytocin receptor were significantly associated with both positive parenting and hemodynamic responses to child stimuli in orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and hippocampus. Conclusions: These findings contribute to the emerging literature on the role of oxytocin in human social behavior and support the feasibility of tracing biological pathways from genes to neural regions to positive maternal parenting behaviors in humans using genetic imaging methods. © 2014 Michalska, Decety, Liu, Chen, Martz, Jacob, Hipwell, Lee, Chronis-Tuscano, Waldman and Lahey

Precision engineering of micrometer and nanometer droplets for ultrasound imaging and therapy

The medical community has interest in improving techniques such as occlusion, therapeutics and imaging through the use of liquid perfluorocarbon droplets. The ability to create a monodispersed population of liquid perfluorocarbon droplets would have the added advantage of uniform acoustic activation parameters. A microfluidic device with a flow-focusing orifice allowed for uniform production of perfluoropentane droplets in the micron and submicron diameter range. These droplets are able to be stored for over two weeks while retaining distribution characteristics. The observed activation of the droplets shows the acoustic threshold as a function of droplet diameter with little variability. Results showed that microfluidic technology with a pressure controlled flow regulator will allow for greater manufacturing control of phase-change perfluorocarbons in the micron and sub-micron size range for acoustic droplet vaporization applications