A review of the ecology, palaeontology and distribution of atlantid heteropods (Caenogastropoda: Pterotracheoidea: Atlantidae)

Fewer than 1% of marine gastropod species live a holoplanktic life. Of these, the shelled heteropods of the family Atlantidae are among the most poorly understood. The atlantids potentially make up an important part of the ocean zooplankton, composing up to 69% of shelled holoplanktic gastropods in the Late Pleistocene to Recent fossil record. They are also likely to be at high risk from current and future global changes, including anthropogenic ocean acidification. However, due to their small size (<12 mm), difficulty of sampling and complicated morphology, we still lack key information about atlantid taxonomy and ecology. This makes it difficult to understand how important they are in the ocean foodweb and how they will be affected by environmental change. Although many studies have been carried out on the atlantids, these have generally been broad and unconnected. Here, we draw together this previous research, summarizing what is currently known about atlantid taxonomy, palaeontology, ecology and biogeography, and aiming to provide a foundation for future research on this group. The data indicate complex behaviours involving seasonal and vertical migration, and demonstrate extended geographical ranges, with implications for understanding the role of atlantids in the ocean foodweb and their sensitivity to environmental changes. This review highlights the urgent need for further taxonomic research on the atlantids, including molecular analysis, and for improved sampling techniques

Gasterópodos holoplanctónicos de la costa occidental De Baja California Sur, en mayo y junio de 1984.

Se analizaron 70 muestras de plancton, recolectadas con red tipo Bongo de mayo a junio de 1984; desde el norte de Isla Cedros, hasta el sur de Bahía Magdalena y abarcando hasta 100 m.n. de la costa. Se identificaron 15 especies de gasterópodos holoplanctónicos cuyo patrón de distribución permite de limitar siete zonas, mismas que tienen influencia de aguas cálidas del Pacífico Central, aguas ecuatoriales y surgencias costeras de diferente intensidad, detectándose al sur un frente templado tropical. Se encontraron a Limacina inflata con densidades hasta de 10 859/1000 m 3, como la especie de mayor importancia en áreas oceánicas, y a Atlanta peroni, en las costeras

Distribución y abundancia de los Thecosomata (Gastropoda) recolectados con red CalVET en agosto de 1985, frente a Bahía Magdalena, Baja California Sur, México

Para valorar la utilidad de la red CalVET en estudios de zooplancton, se analiza la distribución y abundancia de los moluscos tecosomados que se recolectaron con esta red en agosto de 1985, frente a Bahía Magdalena, Baja California Sur. Las muestras se obtuvieron en lances verticales hasta 100 m de profundidad, hechos a cada 5 mn en enfilaciones perpendiculares a la costa y separadas 10 mn entre sí. Las especies identificadas fueron: Limacina inf7ata y L. trochiformis, las más frecuentes y abundantes; Creseis virgula virgula y C. v. constricta, abundantes y de distribución limitada al norte de los 25°N;Desmopterus pacificus, más abundante en aguas costeras; Clio pyramidata,escasa y dispersa y Limacina helicina y Peraclis apicifulva muy raramente. Se determinaron las asociaciones de estas especies, así como las tendencias en su distribución, encontrándose por un análisis de componentes principales, que se relacionan con la latitud, distancia a la costa, temperatura del agua a diferentes profundidades, o bien con rasgos topográficos como el borde de la plataforma continental, las bocas del complejo lagunar de bahía Magdalena, el cabo San Lázaro o el bajo Petrel

Los grupos del zooplancton de colecciones obtenidas con red CalVET en agosto de 1985 frente a la costa occidental de Baja California Sur, México

En este trabajo se analizan los grupos del zooplancton recolectados, en agosto de 1985, con red CalVET en lances verticales hechos desde profundidades entre 20 y 100 ni hasta la superficie, en aguas frente a la costa oeste de Baja California Sur. El objetivo fue determinar la utilidad de dicha red en los estudios que se desarrollan en el Centro Interdisciplinario de Ciencias Marinas (CICIMAR) sobre el zooplancton del Pacífico al noroeste de México. La red CalVET presenta diferencias de tamaño, así como de velocidad, profundidad, duración y trayectoria de arrastre, con la red Bongo empleada comunmente en estudios del zooplancton de la Corriente de California. Las muestras analizadas contienen entre 37,200 y 1,457,500 organismos/1,000 m 3, predominando los copépodos en más del 67%; le siguen eufáusidos, apendicularias, quetognatos, sifonóforos, pterópodos y taliaceos que ascienden a más del 31% y otros 12 grupos planctónicos que abarcan menos del 2%; en estas muestras también fue evidente una mayor presencia de especies de copépodos de tallas pequeñas, así como de fases tempranas de eufáusidos. El análisis de estos grupos permite detectar una tendencia a incrementar sus densidades hacia el norte y hacia la costa, registrándose las mayores al norte y al sur de Bahía Magdalena; además se encuentra que las capturas nocturnas son un poco más abundantes que las diurnas salvo para apendicularias, medusas y anfípodos y que en lances a menos de 100 m de profundidad, las densidades son casi 3 veces mayores que en los realizados a 100 m

Major results from the first plasma campaign of the Wendelstein 7-X stellarator

\u3cp\u3eAfter completing the main construction phase of Wendelstein 7-X (W7-X) and successfully commissioning the device, first plasma operation started at the end of 2015. Integral commissioning of plasma start-up and operation using electron cyclotron resonance heating (ECRH) and an extensive set of plasma diagnostics have been completed, allowing initial physics studies during the first operational campaign. Both in helium and hydrogen, plasma breakdown was easily achieved. Gaining experience with plasma vessel conditioning, discharge lengths could be extended gradually. Eventually, discharges lasted up to 6 s, reaching an injected energy of 4 MJ, which is twice the limit originally agreed for the limiter configuration employed during the first operational campaign. At power levels of 4 MW central electron densities reached 3 10\u3csup\u3e19\u3c/sup\u3e m\u3csup\u3e-3\u3c/sup\u3e, central electron temperatures reached values of 7 keV and ion temperatures reached just above 2 keV. Important physics studies during this first operational phase include a first assessment of power balance and energy confinement, ECRH power deposition experiments, 2nd harmonic O-mode ECRH using multi-pass absorption, and current drive experiments using electron cyclotron current drive. As in many plasma discharges the electron temperature exceeds the ion temperature significantly, these plasmas are governed by core electron root confinement showing a strong positive electric field in the plasma centre.\u3c/p\u3

Candida bloodstream infections in intensive care units: analysis of the extended prevalence of infection in intensive care unit study

Item does not contain fulltextOBJECTIVES: To provide a global, up-to-date picture of the prevalence, treatment, and outcomes of Candida bloodstream infections in intensive care unit patients and compare Candida with bacterial bloodstream infection. DESIGN: A retrospective analysis of the Extended Prevalence of Infection in the ICU Study (EPIC II). Demographic, physiological, infection-related and therapeutic data were collected. Patients were grouped as having Candida, Gram-positive, Gram-negative, and combined Candida/bacterial bloodstream infection. Outcome data were assessed at intensive care unit and hospital discharge. SETTING: EPIC II included 1265 intensive care units in 76 countries. PATIENTS: Patients in participating intensive care units on study day. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Of the 14,414 patients in EPIC II, 99 patients had Candida bloodstream infections for a prevalence of 6.9 per 1000 patients. Sixty-one patients had candidemia alone and 38 patients had combined bloodstream infections. Candida albicans (n = 70) was the predominant species. Primary therapy included monotherapy with fluconazole (n = 39), caspofungin (n = 16), and a polyene-based product (n = 12). Combination therapy was infrequently used (n = 10). Compared with patients with Gram-positive (n = 420) and Gram-negative (n = 264) bloodstream infections, patients with candidemia were more likely to have solid tumors (p < .05) and appeared to have been in an intensive care unit longer (14 days [range, 5-25 days], 8 days [range, 3-20 days], and 10 days [range, 2-23 days], respectively), but this difference was not statistically significant. Severity of illness and organ dysfunction scores were similar between groups. Patients with Candida bloodstream infections, compared with patients with Gram-positive and Gram-negative bloodstream infections, had the greatest crude intensive care unit mortality rates (42.6%, 25.3%, and 29.1%, respectively) and longer intensive care unit lengths of stay (median [interquartile range]) (33 days [18-44], 20 days [9-43], and 21 days [8-46], respectively); however, these differences were not statistically significant. CONCLUSION: Candidemia remains a significant problem in intensive care units patients. In the EPIC II population, Candida albicans was the most common organism and fluconazole remained the predominant antifungal agent used. Candida bloodstream infections are associated with high intensive care unit and hospital mortality rates and resource use