Structural diversity of neuronal calcium sensor proteins and insights for activation of retinal guanylyl cyclase by GCAP1.

Neuronal calcium sensor (NCS) proteins, a sub-branch of the calmodulin superfamily, are expressed in the brain and retina where they transduce calcium signals and are genetically linked to degenerative diseases. The amino acid sequences of NCS proteins are highly conserved but their physiological functions are quite different. Retinal recoverin controls Ca(2) (+)-dependent inactivation of light-excited rhodopsin during phototransduction, guanylyl cyclase activating proteins 1 and 2 (GCAP1 and GCAP2) promote Ca(2) (+)-dependent activation of retinal guanylyl cyclases, and neuronal frequenin (NCS-1) modulates synaptic activity and neuronal secretion. Here we review the molecular structures of myristoylated forms of NCS-1, recoverin, and GCAP1 that all look very different, suggesting that the attached myristoyl group helps to refold these highly homologous proteins into different three-dimensional folds. Ca(2) (+)-binding to both recoverin and NCS-1 cause large protein conformational changes that ejects the covalently attached myristoyl group into the solvent exterior and promotes membrane targeting (Ca(2) (+)-myristoyl switch). The GCAP proteins undergo much smaller Ca(2) (+)-induced conformational changes and do not possess a Ca(2) (+)-myristoyl switch. Recent structures of GCAP1 in both its activator and Ca(2) (+)-bound inhibitory states will be discussed to understand structural determinants that control their Ca(2) (+)-dependent activation of retinal guanylyl cyclases

The genus Sipha Passerini (Hemiptera: Aphididae) in North America

Five species of the aphid genus Sipha Passerini (Hemiptera: Aphididae) are reported in North America and are reviewed herein. Of these species, three are adventive species and include: Sipha elegans del Guercio, Sipha glyceriae (Kaltenbach), and Sipha maydis Passerini. Sipha maydis was discovered in California in 2007 and now has been found in Georgia. The genus also includes two native species: Sipha agropyronensis (Gillette) and Sipha flava (Forbes). Sipha maydis can be distinguished easily from all the other species in the genus that occur in North America because it is black. All the species except S. agropyronensis have been implicated in damage to crop plants. A key to the apterae and alatae of Sipha found in North America is included

Comments on the Emergence and Persistence of Inequality in Premodern Societies

The author discusses the development and persistence of permanent inequality in human societies. He comments on an article which undertakes inequality in premodern societies and proposed that intergenerational wealth transmission is the reason for the evolution and persistence of inequality, mentioning the three categories of wealth including material, relational, and embodied

Intermittent Connectivity for Exploration in Communication-Constrained Multi-Agent Systems

Motivated by exploration of communication-constrained underground environments using robot teams, we study the problem of planning for intermittent connectivity in multi-agent systems. We propose a novel concept of information-consistency to handle situations where the plan is not initially known by all agents, and suggest an integer linear program for synthesizing information-consistent plans that also achieve auxiliary goals. Furthermore, inspired by network flow problems we propose a novel way to pose connectivity constraints that scales much better than previous methods. In the second part of the paper we apply these results in an exploration setting, and propose a clustering method that separates a large exploration problem into smaller problems that can be solved independently. We demonstrate how the resulting exploration algorithm is able to coordinate a team of ten agents to explore a large environment

Depression and Empathy Predict Emotion-Modulated Startle Reactivity

Research supports varied patterns of emotion-modulated startle (EMS) reactivity among depressed individuals. The purpose of this study was to examine whether these varied patterns can be explained by depression, empathic tendencies, and emotional stimuli. The EMS paradigm is a well-validated measure of emotion-modulated reactivity in which the magnitude of startle reflexes in reaction to acoustic stimuli are recorded while participants view pleasant, neutral, and negative images (Lang, Bradley, & Cuthbert, 1990). Young adults (N = 120; Mage = 19.54, SD = 1.41; 75% female) completed self-report rating scales of depression symptoms and cognitive and affective empathic tendencies and the EMS paradigm. Individuals with low depression, regardless of their cognitive (hp2 = .44 and .47) and affective empathic tendencies (hp2 = .49 and .36), and individuals with high depression and high cognitive and affective empathic tendencies (hp2 = .23, .46, respectively) exhibited the typical linear EMS reactivity pattern of increasing startle reflex magnitude from pleasant to neutral to unpleasant images. In contrast, individuals with high depression along with low cognitive and affective empathic tendencies exhibited blunted EMS reactivity patterns (hp2 = .000, .04, respectively). These findings indicate blunted EMS reactivity patterns only in depressed individuals who have low cognitive and affective empathic tendencies and are likely disengaged from emotional stimuli, thus suggesting variability among depressed individuals in motivational states that prime or inhibit the startle reflex

A marine reservoir effect ΔR value for Kitandach, in Prince Rupert Harbour, British Columbia, Canada

Prince Rupert Harbour (PRH), on the north Pacific Coast of British Columbia, contains at least 157 shell middens, of which 66 are known villages, in an area of approximately 180 km. These sites span the last 9500 yr and in some cases are immense, exceeding 20,000 m surface area and several meters in depth. Recent archaeological research in PRH has become increasingly reliant on radiocarbon dates from marine shell for developing chronologies. However, this is problematic as the local marine reservoir effect (MRE) remains poorly understood in the region. To account for the MRE and to better date the Harbour’s sites, we propose a ΔR of 273 ± 38 for the PRH area, based on our work at the site of Kitandach (GbTo-34), a massive shell midden-village centrally located within the Harbour. We followed the multiple paired sample approach for samples from speci fic contexts and ensured contemporaneity within the groups of marine and terrestrial materials by statistically assessing for outliers using the χ2 test. Taking together, the results for this and previous studies, it appears the MRE was fairly constant over the past 5000 yr

The myth ofa population explosion in yamerican society

Desde hace unos años, el público norteamericano está sometido a un verdadero bombardeo propagandista de argumentos antinatalistas, llamamientos emocionales y «slogans» publicitarios sobre el llamado «problema» de,1 crecimiento demográfico en Estados Unidos. Al mismo tiempo, numerosos «expertos» y muchas organizaciones sociales intentan buscar «soluciones» a es'e «problema», para evitar una catástrofe demográfica en el futuro. Estas «soluciones» muchas veces son radicales y carecen de realismo, desde los contraceptivos para los menores de edad hasta el aborto generalizado para todos. En este artículo los autores demuestran, científicamente, la falacia de los planteamientos apocalípticos y antinatalistas en cuanto al caso de Estados Unidos. Lo más importante en la historia demográfica de este países el hecho de que las tasas de fertilidad han ido bajando de forma drástica desde 1800; en la actualidad, la tasa de natalidad está a nivel de reemplazo, y los pronósticos de cara al futuro inmediato indican que eI proceso de declive va a continuar. Este fenómeno se debe a una combinación de factores -un mayor número de mujeres solteras, incorporadas en el trabajo profesional; un incremento de matrimonios tardíos; el cambio de mentalidad con respecto a las familias numerosas- que hacen suponer que la sociedad norteamericana no camina hacia el desastre demográfico, sino hacia un vacío demográfíco. Además, e·1 argumento malthusiano no corresponde a la realidad, y no encuentra apoyo estadísticamente. El impacto del descenso continuo de la fertilidad se sentirá en el futuro no lejano de forma muy negativa, especialmente en las categorías de edad dependientes (menos de 15 y más de 65 años de edad), y llevará consigo problemas socioeconómicos y demográficos graves. Por otra parte, los argumentos sobre la e'scasez de alimentos, las altas densidades de población, la contaminación del medio ambiente, etc., carecen de validez científica y de realismo. Por lo tanto, en Estados Unidos, los abogados de la «explosión demográfica» actúan no sólo en un vacío factual, sino también en un vacío intelectual. Sus argumentos, aunque estén cargados de ruido y de emoción, carecen de sentido común y por tanto defienden una posición mítica