Morphology and dynamics of the jets of comet 67P/Churyumov-Gerasimenko: Early-phase development

Aims. The OSIRIS camera onboard the Rosetta spacecraft obtained close-up views of the dust coma of comet 67P. The jet structures can be used to trace their source regions and to examine the possible effect of gas-surface interaction. Methods. We analyzed the wide-angle images obtained in the special dust observation sequences between August and September 2014. The jet features detected in different images were compared to study their time variability. The locations of the potential source regions of some of the jets are identified by ray tracing. We used a ring-masking technique to calculate the brightness distribution of dust jets along the projected distance. Results. The jets detected between August and September 2014 mostly originated in the Hapi region. Morphological changes appeared over a timescale of several days in September. The brightness slope of the dust jets is much steeper than the background coma. This might be related to the sublimation or fragmentation of the emitted dust grains. Interaction of the expanding gas flow with the cliff walls on both sides of Hapi could lead to erosion and material down-fall to the nucleus surface.

Scientific assessment of the quality of OSIRIS images

Context. OSIRIS, the scientific imaging system onboard the ESA Rosetta spacecraft, has been imaging the nucleus of comet 67P/Churyumov-Gerasimenko and its dust and gas environment since March 2014. The images serve different scientific goals, from morphology and composition studies of the nucleus surface, to the motion and trajectories of dust grains, the general structure of the dust coma, the morphology and intensity of jets, gas distribution, mass loss, and dust and gas production rates. Aims. We present the calibration of the raw images taken by OSIRIS and address the accuracy that we can expect in our scientific results based on the accuracy of the calibration steps that we have performed. Methods. We describe the pipeline that has been developed to automatically calibrate the OSIRIS images. Through a series of steps, radiometrically calibrated and distortion corrected images are produced and can be used for scientific studies. Calibration campaigns were run on the ground before launch and throughout the years in flight to determine the parameters that are used to calibrate the images and to verify their evolution with time. We describe how these parameters were determined and we address their accuracy. Results. We provide a guideline to the level of trust that can be put into the various studies performed with OSIRIS images, based on the accuracy of the image calibration.

The origin and development of hyperammonemia following exposure to hydrazine in rabbits

Hydrazine $\rm (N\sb2H\sb4),$ an important liquid propellant and derivative chemical for pharmaceuticals and pesticides, produces coma and convulsions sometimes resulting in death. Hyperammonia was found in rabbits exposed to 18 mg/Kg of hydrazine. Results of Part One of this study of rabbits emphasize the importance of acute ammonia toxicity during the first three hours following exposure to hydrazine. At no time during this post exposure period did a significant reduction of hydrazine to ammonia occur. Therefore, the elevated blood ammonia was apparently secondary to the effects of hydrazine on metabolic pathways. Further, the results support the theory of competitive inhibition of ammonia by hydrazine and emphasize the need to monitor plasma ammonia following toxic exposure to hydrazine.^ In Part Two, urea, ammonia, CO$\sb2,$ pH, glucose, sodium, potassium, chloride and creatinine were measured for up to 4 hours following injection of 18 mg/Kg of hydrazine in each of two groups of five rabbits. One group received normal saline and the other group received 5% dextrose and water/normal saline. Hyperammonemia, minimal metabolic acidosis and hyperglycemia without increased urea were found in the rabbits receiving normal saline intravenous infusion and hydrazine injection. Hence, hypoglycemia does not appear to play a role in the development of hyperammonemia. A significant difference in the elevated ammonia levels between the two groups receiving dextrose and water/normal saline and normal saline at 1 hour occurred. There was no significant difference in the elevated ammonia levels seen between the two groups receiving dextrose and water/normal saline and normal saline at 2.5 and 4 hours. Thus at 1 hour the group receiving dextrose was able to utilize excess glucose to detoxify ammonia, while at 2.5 and 4 hours there was no significant difference in the two groups' ability to detoxify ammonia.^ Findings support the theory that hydrazine inhibits the formation of urea resulting in hyperammonemia. Results suggest that hydrazine at 18 mg/Kg, a known hypoglycemic agent, causes serious hyperammonemia without increasing urea production during hyperglycemia. These experiments support a unified theory for the toxic mechanism of action of hydrazine, i.e., the intermediary metabolic effects of hydrazine are brought about by the formation of hydrazones which encumber ATP synthesis and vitamin B$\sb6$ enzymatic reactions. ^

SEVERE HEAD TRAUMA, EMERGENCY TRANSPORT, AND PATIENT OUTCOME

Trauma and severe head injuries are important issues because they are prevalent, because they occur predominantly in the young, and because variations in clinical management may matter. Trauma is the leading cause of death for those under age 40. The focus of this head injury study is to determine if variations in time from the scene of accident to a trauma center hospital makes a difference in patient outcomes.^ A trauma registry is maintained in the Houston-Galveston area and includes all patients admitted to any one of three trauma center hospitals with mild or severe head injuries. A study cohort, derived from the Registry, includes 254 severe head injury cases, for 1980, with a Glasgow Coma Score of 8 or less.^ Multiple influences relate to patient outcomes from severe head injury. Two primary variables and four confounding variables are identified, including time to emergency room, time to intubation, patient age, severity of injury, type of injury and mode of transport to the emergency room. Regression analysis, analysis of variance, and chi-square analysis were the principal statistical methods utilized.^ Analysis indicates that within an urban setting, with a four-hour time span, variations in time to emergency room do not provide any strong influence or predictive value to patient outcome. However, data are suggestive that at longer time periods there is a negative influence on outcomes. Age is influential only when the older group (55-64) is included. Mode of transport (helicopter or ambulance) did not indicate any significant difference in outcome.^ In a multivariate regression model, outcomes are influenced primarily by severity of injury and age which explain 36% (R('2)) of variance. Inclusion of time to emergency room, time to intubation, transport mode and type injury add only 4% (R('2)) additional contribution to explaining variation in patient outcome.^ The research concludes that since the group most at risk to head trauma is the young adult male involved in automobile/motorcycle accidents, more may be gained by modifying driving habits and other preventive measures. Continuous clinical and evaluative research are required to provide updated clinical wisdom in patient management and trauma treatment protocols. A National Institute of Trauma may be required to develop a national public policy and evaluate the many medical, behavioral and social changes required to cope with the country's number 3 killer and the primary killer of young adults.^

Reconfiguración de los modos de vida : Un estudio de los procesos de socialización de las familias de origen campesina en Huánuco, Perú

Esta pesquisa tem como objetivo central analisar os processos de socializaçao vivenciados por duas geraçoes de famílias peruanas, especificamente,os processos detransmissao e aquisiçao de valores, práticas culturais e políticas, enfatizandoos modos de relacionamento coma escola, a família e otrabalho. Os núcleos familiares de origem campesina migraram da zona rural para a periferia da cidade a partir de 1980, devido ao conflito armado caracterizado pelas açoes de violência entre o Estado, representado pelo exército, e o Sendero Luminoso. Trata-se, portanto, de grupos familiares que migraram em funçao da violência e da pobreza, que os determinava na regiao rural e encontraram na cidade condiçoes de vida e trabalho também marcados pela pobreza, acrescidas de todas as dificuldades de adaptaçao ao mundo urbano. Assim, esta pesquisa visa entender os processos de socializaçao que mediaram essa transformaçao. Para tanto, trata-se de umainvestigaçaode caráter qualitativo, queutilizou como principal técnicade coleta de dados, entrevistas de caráter biográfico, pensadas como histórias de vida, além obviamente da observaçao da comunidade em questao

Reconfiguración de los modos de vida : Un estudio de los procesos de socialización de las familias de origen campesina en Huánuco, Perú

Esta pesquisa tem como objetivo central analisar os processos de socializaçao vivenciados por duas geraçoes de famílias peruanas, especificamente,os processos detransmissao e aquisiçao de valores, práticas culturais e políticas, enfatizandoos modos de relacionamento coma escola, a família e otrabalho. Os núcleos familiares de origem campesina migraram da zona rural para a periferia da cidade a partir de 1980, devido ao conflito armado caracterizado pelas açoes de violência entre o Estado, representado pelo exército, e o Sendero Luminoso. Trata-se, portanto, de grupos familiares que migraram em funçao da violência e da pobreza, que os determinava na regiao rural e encontraram na cidade condiçoes de vida e trabalho também marcados pela pobreza, acrescidas de todas as dificuldades de adaptaçao ao mundo urbano. Assim, esta pesquisa visa entender os processos de socializaçao que mediaram essa transformaçao. Para tanto, trata-se de umainvestigaçaode caráter qualitativo, queutilizou como principal técnicade coleta de dados, entrevistas de caráter biográfico, pensadas como histórias de vida, além obviamente da observaçao da comunidade em questao

Reconfiguración de los modos de vida : Un estudio de los procesos de socialización de las familias de origen campesina en Huánuco, Perú

Esta pesquisa tem como objetivo central analisar os processos de socializaçao vivenciados por duas geraçoes de famílias peruanas, especificamente,os processos detransmissao e aquisiçao de valores, práticas culturais e políticas, enfatizandoos modos de relacionamento coma escola, a família e otrabalho. Os núcleos familiares de origem campesina migraram da zona rural para a periferia da cidade a partir de 1980, devido ao conflito armado caracterizado pelas açoes de violência entre o Estado, representado pelo exército, e o Sendero Luminoso. Trata-se, portanto, de grupos familiares que migraram em funçao da violência e da pobreza, que os determinava na regiao rural e encontraram na cidade condiçoes de vida e trabalho também marcados pela pobreza, acrescidas de todas as dificuldades de adaptaçao ao mundo urbano. Assim, esta pesquisa visa entender os processos de socializaçao que mediaram essa transformaçao. Para tanto, trata-se de umainvestigaçaode caráter qualitativo, queutilizou como principal técnicade coleta de dados, entrevistas de caráter biográfico, pensadas como histórias de vida, além obviamente da observaçao da comunidade em questao

Annual response of two Mediterranean azooxanthellate temperate corals to low-pH and high-temperature conditions

Ocean acidification (OA) and warming related to the anthropogenic increase in atmospheric CO2 have been shown to have detrimental effects on several marine organisms, especially those with calcium carbonate structures such as corals. In this study, we evaluate the response of two Mediterranean shallow-water azooxanthellate corals to the projected pH and seawater temperature (ST) scenarios for the end of this century. The colonial coral Astroides calycularis and the solitary Leptopsammia pruvoti were grown in aquaria over a year under two fixed pH conditions, control (8.05 pHT units) and low (7.72 pHT units), and simulating two annual ST cycles, natural and high (+3 °C). The organic matter (OM), lipid and protein content of the tissue and the skeletal microdensity of A. calycularis were not affected by the stress conditions (low pH, high ST), but the species exhibited a mean 25 % decrease in calcification rate at high-ST conditions at the end of the warm period and a mean 10 % increase in skeletal porosity under the acidified treatment after a full year cycle. Conversely, an absence of effects on calcification and skeletal microdensity of L. pruvoti exposed to low-pH and high-ST treatments contrasted with a significant decrease in the OM, lipid and protein content of the tissue at high-ST conditions and a 13 % mean increase in the skeletal porosity under low-pH conditions following a full year of exposure. This species-specific response suggests that different internal self-regulation strategies for energy reallocation may allow certain shallow-water azooxanthellate corals to cope more successfully than others with global environmental changes.