29 research outputs found
Reproductive biology of the spotback skate Atlantoraja castelnaui in the south-west Atlantic Ocean
This study provides information on the reproduction of spotback skate Atlantoraja castelnaui. A total of 232 individuals (119 females and 113 males) were obtained from surveys carried out between 2003 and 2006, from the south-west Atlantic Ocean, between 34 and 42° S and <50 m deep; another 514 specimens (241 females and 273 males) were obtained between 2005 and 2007 from commercial fishery operations carried out in the same area and landings in the port of Mar del Plata, Argentina. Males ranged from 185 to 1250 mm total length (L T) and females from 243 to 1368 mm L T. Length at maturity was estimated to be 980 mm for males and 1089 mm L T for females. Lack of variation of testis mass together with the continuous production of mature spermatocyst and spermatozoa in deferent ducts suggested that males can reproduce throughout the year. Females reproduced year-round with peaks of reproductive activity an integral part of a continuous cycle. This conclusion is corroborated by the seasonal variation of ovaries, oviducal gland and the occurrence of females with eggs in the uterus throughout the year. Results from this study indicate that A. castelnaui is very susceptible to fishery pressure.Fil: Colonello, J. C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Garcia, Mirta Lidia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Lasta, C.. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Menni, Roberto Carlos. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico Zoología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin
WIRED: World Wide Web Interactive Remote Event Display
WIRED is a framework, written in Java, to build High Energy Physics event displays that can be used across the network. To guarantee portability across all platforms, WIRED is implemented in the Java language and uses the Swing user interface component set. It can be used as a stand-alone application or as an applet inside a WWW browser. The graphical user interface allows for multiple views and for multiple controls acting on those views. A detector tree control is available to toggle the visibility of parts of the events and detector geometry. XML (Extensible Markup Language), RMI (Remote Method Invocation) and CORBA loaders can be used to load event data as well as geometry data, and to connect to FORTRAN, C, C++ and Java reconstruction programs. Non-linear and non-Cartesian projections (e.g. fish-eye, rho-phi, rho-Z, phi-Z) provide special views to get a better understanding of events. WIRED has grown to be a framework in use and under development in several HEP experiments (ATLAS, CHORUS, DELPHI, LHCb, BaBar, D0 and ZEUS). WIRED event displays have also proven to be useful to explain High Energy Physics to the general public. Both CERN, in its travelling exhibition and MicroCosm, and RAL, during its open days, have displays set up
Mating with Stressed Males Increases the Fitness of Ant Queens
BACKGROUND: According to sexual conflict theory, males can increase their own fitness by transferring substances during copulation that increase the short-term fecundity of their mating partners at the cost of the future life expectancy and re-mating capability of the latter. In contrast, sexual cooperation is expected in social insects. Mating indeed positively affects life span and fecundity of young queens of the male-polymorphic ant Cardiocondyla obscurior, even though males neither provide nuptial gifts nor any other care but leave their mates immediately after copulation and die shortly thereafter. PRINCIPAL FINDINGS: Here, we show that mating with winged disperser males has a significantly stronger impact on life span and reproductive success of young queens of C. obscurior than mating with wingless fighter males. CONCLUSIONS: Winged males are reared mostly under stressful environmental conditions, which force young queens to disperse and found their own societies independently. In contrast, queens that mate with wingless males under favourable conditions usually start reproducing in the safety of the established maternal nest. Our study suggests that males of C. obscurior have evolved mechanisms to posthumously assist young queens during colony founding under adverse ecological conditions
Annual fecundity assessment for the Rio skate Rioraja agassizi (chondrichthyes: arhynchobatidae) endemic to a neotropical area (Southeastern Brazil)
Seasonal and Long-Term Changes in Relative Abundance of Bull Sharks from a Tourist Shark Feeding Site in Fiji
Shark tourism has become increasingly popular, but remains controversial because
of major concerns originating from the need of tour operators to use bait or
chum to reliably attract sharks. We used direct underwater sampling to document
changes in bull shark Carcharhinus leucas relative abundance at
the Shark Reef Marine Reserve, a shark feeding site in Fiji, and the
reproductive cycle of the species in Fijian waters. Between 2003 and 2009, the
total number of C. leucas counted on each day ranged from 0 to
40. Whereas the number of C. leucas counted at the feeding site
increased over the years, shark numbers decreased over the course of a calendar
year with fewest animals counted in November. Externally visible reproductive
status information indicates that the species' seasonal departure from the
feeding site may be related to reproductive activity
Mating plugs in polyandrous giants: Which sex produces them, when, how and why?
10.1371/journal.pone.0040939PLoS ONE77