Postsettlement growth of two estuarine crab species, Chasmagnathus granulata and Cyrtograpsus angulatus (Crustacea, Decapoda, Grapsidae): laboratory and field observations

The estuarine grapsid crabs Chasmagnathus granulata and Cyrtograpsus angulatus belong to the most typical and dominant inhabitants of brackish coastal lagoons in southeastern South America. In a combined laboratory and field investigation of juvenile growth, we measured the increase in body size in these species under controlled conditions as well as in field experiments (in Mar Chiquita lagoon, Argentina), seasonal changes in size frequency distribution of a natural population, and growth related changes in selected morphometric traits of male and female juveniles (relations between carapace width, carapace length, propodus height and length of the cheliped, and pleon width). At 24°C, Cy. angulatus grew faster than Ch. granulata; it reached the crab-9 instar (C9; 13 mm carapace width) after 92 days, while Ch. granulata required 107 days to reach the C8 instar (7.4 mm). At 12°C, growth ceased in both species. The pleon begins to show sexual differences in the C5 (Cy. angulatus) and C8 instar (Ch. granulata), respectively, while the chelae differentiate earlier in Ch. granulata than in Cy. angulatus (in C4 vs C6). In the field, growth was maximal in summer, and was generally faster than in laboratory cultures. However, there is great individual variability in size (about 25% even in the first crab instar) and in size increments at ecdysis, increasing throughout juvenile growth. Our data indicate that, in the field, small-scale and short-term variations in feeding conditions, temperature, and salinity account for an extremely high degree of variability in the absolute and relative rates of growth as well as in the time to sexual differentiation

Do presumptions of negligence incentivize optimal precautions?

In most jurisdictions, the burden of producing evidence on a contested issue traditionally falls on plaintiffs. In a tort claim, this de facto creates a presumption of non-negligence in favor of injurers. Some legal systems in Europe placed renewed attention on “presumed liability” rules, which instead create a presumption of negligence against injurers. In this paper, we analyze the effects of alternative legal presumptions on parties’ care incentives in the presence of discovery errors. Differently from what was suggested in prior research, we show that legal presumptions do affect primary behavior: presuming that the injurer was (not) negligent strengthens (weakens) his care incentives in situations where the plaintiff faces probatory difficulties. We analyze how these effects should inform the choice of evidence regimes to improve the robustness of liability rules, and to minimize the dilutive effect of imperfect discovery on individuals’ care incentives

Resonant optical control of the structural distortions that drive ultrafast demagnetization in Cr2_2O3_3

We study how the color and polarization of ultrashort pulses of visible light can be used to control the demagnetization processes of the antiferromagnetic insulator Cr$_2$O$_3$. We utilize time-resolved second harmonic generation (SHG) to probe how changes in the magnetic and structural state evolve in time. We show that, varying the pump photon-energy to excite either localized transitions within the Cr or charge transfer states, leads to markedly different dynamics. Through a full polarization analysis of the SHG signal, symmetry considerations and density functional theory calculations, we show that, in the non-equilibrium state, SHG is sensitive to {\em both} lattice displacements and changes to the magnetic order, which allows us to conclude that different excited states couple to phonon modes of different symmetries. Furthermore, the spin-scattering rate depends on the induced distortion, enabling us to control the timescale for the demagnetization process. Our results suggest that selective photoexcitation of antiferromagnetic insulators allows fast and efficient manipulation of their magnetic state.Comment: 7 pages, 5 figure

Desarrollo larvario de Pilumnoides hassleri (Decapoda: Brachyura: Pilumnoididae) cultivado en laboratorio, con una revisión de la sistematica de Pilumnoididae utilizando caracteres larvarios

The genus Pilumnoides is an interesting taxon because its systematic position, based on adult characters, remains unclear. These xanthoid crabs have been related to the Carpiliidae, Goneplacidae and Eriphioidea. P. hassleri A. Milne Edwards, 1880 lives in Brazilian, Uruguayan and Argentinian coasts as far south as the Magellan Strait (southwestern Atlantic). Larvae of P. hassleri from females collected in the harbour of Mar del Plata were reared in the laboratory from zoea I to megalopa and the first larval stage, and described. The species passed through 5 zoeal stages and a megalopa. Larval characters were compared with the previous description of larvae from the southeastern Pacific species P. perlatus and with species of Carpilius, Goneplax and Eriphia in order to review the relationships between these taxa.El género Pilumnoides es un taxón interesante dado que su posición sistemática, basada en caracteres adultos, permanece poco clara. Estos cangrejos xantoideos han sido relacionados con las familias Carpiliidae, Goneplacidae y Eriphioidea. P. hassleri A. Milne Edwards, 1880 vive en las costas de Brasil, Uruguay y Argentina hasta el Estrecho de Magallanes (Atlántico Sudoccidental). Se cultivaron larvas de P. hassleri, provenientes de hembras colectadas en el puerto de Mar del Plata, desde la zoea Ihasta la megalopa y el primer estadio de cangrejo, y posteriormente se describieron. La especie pasa por 5 estadios de zoea y una megalopa. Las características larvarias se compararon con descripciones previas de larvas de P. perlatus del Pacífico Suroriental, y con especies de Carpilius, Goneplax y Eriphia con el objetivo de rever las relaciones entre estos taxa

Brain metastases: an overview

So far brain metastases represent a critical stage of a disease course and the frequency is increasing over the years. The treatment of brain metastases should be individualized for each patient: in case of single brain metastasis, surgery or radiosurgery should be considered as first options of treatment; in case of multiple lesions, whole-brain radiotherapy is the standard of care in association with systemic therapy or surgery/radiosurgery. Chemotherapy should be considered when surgery or radiation therapy are not possible. In the last decades, TKIs or monoclonal antibodies have shown increase in overall response rate and overall survival in Phase II-III trials. The aim of this paper is to make an overview of the current approaches in management of patients with brain metastases

Uso de hábitat, crecimiento relativo y talla de madurez, calculada mediante diferentes modelos, del cangrejo violeta Platyxanthus crenulatus (Decapoda: Brachyura)

We describe the most noteworthy changes occurring during the post-metamorphic phase in both sexes of the purple stone crab Platyxanthus crenulatus. Spatial structure of the populations by size and early changes in colour pattern and relative growth of chelae suggest an ontogenic migration from intertidal to deeper waters. Before reaching maturity and laying eggs, females undergo a tight sequence of morpho-physiologic changes over a narrow size range (44-64 mm carapace width [CW]). In contrast, males undergo two main phases related to sexual maturity. Early in their lives, they develop sperm and accelerate the relative growth of the chelae (35-45 mm CW). Morphologic maturity of males comes later, when relative growth rate reaches the maximum and decelerate (65-70 mm CW). Adult males are larger and develop conspicuously largest chelae than females. Morphometric analyses were performed by two different techniques: the traditional procedure, which describes relative growth relationships as power functions; and an alternative, smoothing spline–based model that is non-dependent on previous assumptions. The results of the alternative analysis were coherent with other reproductive indicators and ancillary observations, allowing a more comprehensive understanding of the relative growth. We provide supporting material containing the respective script written in R program to be used freely in future studies.Se describen los eventos más remarcables durante la ontogenia de la fase post-metamórfica del cangrejo violeta de las rocas Platyxanthus crenulatus. Las poblaciones estudiadas aparecen estructuradas por talla, lo que sumado a cambios tempranos en el patrón de coloración y en la tasa de crecimiento relativo de las quelas de ambos sexos, sugiere la existencia de una migración ontogénica desde el intermareal hacia aguas más profundas. Antes de alcanzar la madurez y extruir huevos, las hembras atraviesan una serie de cambios morfo-fisiológicos en un rango de tallas estrecho (44-64 mm). En contraste los machos muestran dos fases bien diferenciadas en relación a la madurez sexual. Tempranamente desarrollan esperma y aceleran el crecimiento relativo de las pinzas (35-45 mm). La madurez morfológica se alcanza posteriormente cuando la tasa de crecimiento relativo alcanza su máximo y comienza a desacelerarse (65-70 mm). Los machos adultos son más grandes y tienen quelas de mayor tamaño que las de las hembras. Los análisis morfométricos fueron realizados aplicando paralelamente dos técnicas diferentes: el procedimiento tradicional, que describe al crecimiento relativo como una función potencial, y un método alternativo, no dependiente de supuestos a priori, basados en splines. Los resultados del análisis alternativo fueron coherentes con los demás indicadores reproductivos y observaciones auxiliares permitiendo una comprensión más amplia del crecimiento relativo. Se adjuntan los comandos necesarios para aplicar ambos métodos libremente usando el programa R

Mass production of event simulations for the BaBar experiment using the Grid

The BaBar experiment has been taking data since 1999, investigating the violation of charge and parity (CP) symmetry in the field of High Energy Physics. Event simulation is an intensive computing task, due to the complexity of the algorithm based on the Monte Carlo method implemented using the GEANT engine. The simulation input data are stored in ROOT format, they are classified into two categories: conditions data for describing the detector status when data are recorded, and background triggers data for including the noise signal necessary to obtain a realistic simulation. In order to satisfy these requirements, in the traditional BaBar computing model events are distributed over several sites involved in the collaboration where each site manager centrally manages a private farm dedicated to simulation production. The new grid approach applied to the BaBar production framework is discussed along with the schema adopted for data deployment via Xrootd/Scalla servers, including data management using grid middleware on distributed storage facilities spread over the INFN-GRID network. A comparison between the two models is provided, describing also the custom applications developed for performing the whole production task on the grid and showing the results achieved

Diferencias interpoblacionales en el ciclo reproductivo femenino del cangrejo estuárico Chasmagnathus granulatus Dana, 1851 (Brachyura: Grapsoidea: Varunidae) del Atlántico sudoccidental

The female reproductive biology of Chasmagnathus granulatus Dana, a semiterrestrial burrowing crab endemic to the southwestern Atlantic, was compared in two contrasting coastal habitats: San Antonio (SA, marine) and Mar Chiquita (MC, estuarial). Mature females were collected monthly for 1.5 years and the ovarian cycle was described using a qualitative scale. Gonadosomatic (GSI) and hepatosomatic (HSI) indexes were calculated. The highest GSI and HSI occurred early in the reproductive season in SA and during the non-reproductive season in MC. The beginning and duration of the reproductive season also differed between populations: it started later and was shorter in SA. In MC, secondary vitellogenesis continued when the reproductive season had finished, and the ovaries remained fully developed throughout the non-reproductive season (winter). Therefore, females of MC were ready to lay eggs as soon as spring environmental conditions appeared. However, SA females did not attain a fully developed ovary during winter. A limited food supply would restrict the available energy to complete secondary vitellogenesis at the end of the reproductive season in SA, after the last spawning. Thus, the vitellogenic cycle should be completed in the following spring, causing a delay in the beginning of the reproductive period. In addition, the higher temperature amplitude may cause the reproductive period in SA to end early.La biología reproductiva de las hembras de Chasmagnathus granulatus Dana, un cangrejo semiterrestre y excavador endémico del Atlántico Sudoccidental, fue comparada entre dos localidades costeras con regímenes ambientales contrastantes: San Antonio (SA, marino) y Mar Chiquita (MC, estuarial). Hembras maduras fueron recolectadas mensualmente por 1.5 años y el ciclo ovárico fue descrito usando una escala cualitativa. Los índices gonadosomático (GSI) y hepatosomático (HSI) fueron calculados. Los mayores valores de GSI y HSI tuvieron lugar al inicio de la estación reproductiva en SA, y durante la estación no reproductiva en MC. El inicio y duración de la estación reproductiva también difirieron entre las poblaciones: ésta comenzó más tarde y fue más corta en SA. En MC, la vitelogénesis secundaria continuó cuando la estación reproductiva había finalizado, y el ovario permaneció desarrollado durante la estación no reproductiva (invierno). En consecuencia, las hembras de MC estaban listas para poner sus huevos tan pronto como aparecieron las condiciones ambientales de primavera. Por el contrario, las hembras de SA no alcanzaron un completo desarrollo del ovario durante el invierno. Un suministro limitado de alimento restringiría la energía disponible para completar la vitelogénesis secundaria al final de la estación reproductiva en SA, después de la última puesta. De ese modo, el ciclo vitelogénico debió completarse en la primavera siguiente, provocando un retraso en el comienzo de la estación reproductiva. Adicionalmente, la mayor amplitud térmica provocaría que la estación reproductiva finalice más temprano en SA

Diagnosis of occult tuberculosis in hematological malignancy by enumeration of antigen-specific T cells.

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