245 research outputs found
The effect of some processing conditions on the characteristics of biodegradable microspheres obtained by an emulsion solvent evaporation process
Unloaded microspheres were prepared from polyhydroxybutyrate (PHB) and polyhydroxybutyrate-co-valerate (PHB-HV) polymers using an oil-in-water emulsion solvent evaporation method. The study was conducted to evaluate how the polymer and some process parameters affect properties of the final microspheres such as particle size, superficial area, zeta potential, surface morphology and microsphere degradation. The variables included surfactant concentration in the emulsion water phase and solvent composition. From the results, it was found that the parameters affecting microsphere size the most were surfactant concentration in the emulsion water phase and solvent composition. Properties such as zeta potential, surface area and surface morphology remained pratically unchanged over the range of the processing conditions studied here.011
A giant squid architeuthis sp. (mollusca, cephalopoda) stranded on the Patagonian shore of Argentina
A female giant squid was stranded in Bustamante Bay, Argentina (45°08’S, 66°31’W), in May 1996; it was identified as Architeuthis sp. The main morphometric data are given and compared with South Atlantic Oceanrecords for this genus. Parasites found in the stomach, caecum and intestine are provisionally identified to genus
Environmental benchmarks based on ecotoxicological assessment with planktonic species might not adequately protect benthic assemblages in lotic systems
Freshwater ecosystems face widespread diffuse and point-source contamination. Species Sensitivity Distributions (SSDs) have been used as a tool to determine chemical concentration benchmarks that represent protective levels for most species in the environment. Here we used a SSD approach to assess on the adequacy of standard planktonic organisms to reflect the response of benthic communities, critically supporting the structure and function of lotic ecosystems. For the purpose, SSDs reflecting non-lethal responses of standard planktonic and selected benthic organisms were built based on EC50 values (collected in the literature or estimated following testing herein) regarding three model contaminants: potassium dichromate (PD), 3,5-dichlorophenol (DCP) and lead chloride (LC). The derived HC5 estimates were discriminatory between chemicals and the uncertainty associated with the estimate was remarkably low. The HC5 estimates with corresponding uncertainty were generally within the same order of magnitude for the three chemicals tested, with better discrimination between chemicals regarding their hazardous potential being achieved for benthic organisms: DCP was clearly less hazardous than PD, but LC tends to be as hazardous as PD and DCP (assuming the confidence interval ranges). Moreover, benthic communities were more sensitive to both DCP and PD, in this later case the HC5 being lower by more than one order of magnitude than that found for planktonic communities; for LC, confidence intervals overlapped, preventing a feasible assumption regarding differential sensitivity of the compared communities. Microphytobenthos was highlighted as the most sensitive group to the three tested chemicals in SSDs covering the benthic compartment, while SSDs with planktonic organisms did not consistently show trends in sensitivity ordering. Overall, our results suggest that protective benchmarks retrieved from SSDs built with the responses of standard planktonic organisms (which are the most commonly used for regulation purposes) do not adequately protect benthic communities.publishe
Estimation of starvation and diel variation of the RNA/DNA ratios in field-caught Sardina pilchardus larvae off the north of Spain
Simple Hardware-Efficient Long Convolutions for Sequence Modeling
State space models (SSMs) have high performance on long sequence modeling but
require sophisticated initialization techniques and specialized implementations
for high quality and runtime performance. We study whether a simple alternative
can match SSMs in performance and efficiency: directly learning long
convolutions over the sequence. We find that a key requirement to achieving
high performance is keeping the convolution kernels smooth. We find that simple
interventions--such as squashing the kernel weights--result in smooth kernels
and recover SSM performance on a range of tasks including the long range arena,
image classification, language modeling, and brain data modeling. Next, we
develop FlashButterfly, an IO-aware algorithm to improve the runtime
performance of long convolutions. FlashButterfly appeals to classic Butterfly
decompositions of the convolution to reduce GPU memory IO and increase FLOP
utilization. FlashButterfly speeds up convolutions by 2.2, and allows
us to train on Path256, a challenging task with sequence length 64K, where we
set state-of-the-art by 29.1 points while training 7.2 faster than
prior work. Lastly, we introduce an extension to FlashButterfly that learns the
coefficients of the Butterfly decomposition, increasing expressivity without
increasing runtime. Using this extension, we outperform a Transformer on
WikiText103 by 0.2 PPL with 30% fewer parameters
Alternative usage of miRNA-biogenesis co-factors in plants at low temperatures
Plants use molecular mechanisms to sense temperatures, trigger quick adaptive responses and thereby cope with environmental changes. MicroRNAs (miRNAs) are key regulators of plant development under such conditions. The catalytic action of DICER LIKE 1 (DCL1), in conjunction with HYPONASTIC LEAVES 1 (HYL1) and SERRATE (SE), produces miRNAs from double-stranded RNAs. As plants lack a stable internal temperature to which enzymatic reactions could be optimized during evolution, reactions such as miRNA processing have to be adjusted to fluctuating environmental temperatures. Here, we report that with decreasing ambient temperature, the plant miRNA biogenesis machinery becomes more robust, producing miRNAs even in the absence of the key DCL1 co-factors HYL1 and SE. This reduces the morphological and reproductive defects of se and hyl1 mutants, restoring seed production. Using small RNA-sequencing and bioinformatics analyses, we have identified specific miRNAs that become HYL1/SE independent for their production in response to temperature decrease. We found that the secondary structure of primary miRNAs is key for this temperature recovery. This finding may have evolutionary implications as a potential adaptation-driving mechanism to a changing climate.Fil: RĂ©, Delfina Adela. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto de AgrobiotecnologĂa del Litoral. Universidad Nacional del Litoral. Instituto de AgrobiotecnologĂa del Litoral; ArgentinaFil: Lang, Patricia L. M.. Institut Max Planck Fuer Gesellschaft. Institut Fur Entwicklungsbiolobie. Developmental Biology; AlemaniaFil: Yones, Cristian Ariel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto de InvestigaciĂłn en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de IngenierĂa y Ciencias HĂdricas. Instituto de InvestigaciĂłn en Señales, Sistemas e Inteligencia Computacional; ArgentinaFil: Arce, AgustĂn Lucas. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto de AgrobiotecnologĂa del Litoral. Universidad Nacional del Litoral. Instituto de AgrobiotecnologĂa del Litoral; ArgentinaFil: Stegmayer, Georgina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto de InvestigaciĂłn en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de IngenierĂa y Ciencias HĂdricas. Instituto de InvestigaciĂłn en Señales, Sistemas e Inteligencia Computacional; ArgentinaFil: Milone, Diego Humberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto de InvestigaciĂłn en Señales, Sistemas e Inteligencia Computacional. Universidad Nacional del Litoral. Facultad de IngenierĂa y Ciencias HĂdricas. Instituto de InvestigaciĂłn en Señales, Sistemas e Inteligencia Computacional; ArgentinaFil: Manavella, Pablo AndrĂ©s. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto de AgrobiotecnologĂa del Litoral. Universidad Nacional del Litoral. Instituto de AgrobiotecnologĂa del Litoral; Argentin
A review on polycyclic aromatic hydrocarbons distribution in freshwater ecosystems and their toxicity to benthic fauna
Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds, found ubiquitously in all environmental compartments. PAHs are considered hazardous pollutants, being of concern to both the environmental and human health. In the aquatic environment, PAHs tend to accumulate in the sediment due to their high hydrophobicity, and thus sediments can be considered their ultimate sink. Concurrently, sediments comprise important habitats for benthic species. This raises concern over the toxic effects of PAHs to benthic communities. Despite PAHs have been the subject of several reviews, their toxicity to freshwater benthic species has not been comprehensively discussed. This review aimed to provide an overview on PAHs distribution in freshwater environments and on their toxicity to benthic fauna species. The distribution of PAHs between sediments and the overlying water column, given by the sediment-water partition coefficient, revealed that PAHs concentrations were 2 to 4 orders of magnitude higher in sediments than in water. The sediment-water partition coefficient was positively correlated to PAHs hydrophobicity. Toxicity of PAHs to benthic fauna was addressed through Species Sensitivity Distributions. The derived hazardous concentration for 5% of the species (HC5) decreased as follows: NAP (376 ÎĽg L-1) > PHE > PYR > FLT > ANT (0.854 ÎĽg L-1), varying by 3 orders of magnitude. The hazardous concentrations (HC5) to benthic species were inversely correlated to the hydrophobicity of the individual PAHs. These findings are pertinent for environmental risk assessment of these compounds. This review also identified future challenges regarding the environmental toxicity of PAHs to freshwater benthic communities, namely the need for updating the PAHs priority list and the importance of comprehensively and more realistically assess the toxicity of PAHs in combination with other stressors, both chemical and climate-related.publishe
Zymophagy, a novel selective autophagy pathway mediated by VMP1-USP9x-p62, prevents pancreatic cell death.
Autophagy has recently elicited significant attention as a mechanism that either protects or promotes cell death, although different autophagy pathways, and the cellular context in which they occur, remain to be elucidated. We report a thorough cellular and biochemical characterization of a novel selective autophagy that works as a protective cell response. This new selective autophagy is activated in pancreatic acinar cells during pancreatitis-induced vesicular transport alteration to sequester and degrade potentially deleterious activated zymogen granules. We have coined the term “zymophagy” to refer to this process. The autophagy-related protein VMP1, the ubiquitin-protease USP9x, and the ubiquitin-binding protein p62 mediate zymophagy. Moreover, VMP1 interacts with USP9x, indicating that there is a close cooperation between the autophagy pathway and the ubiquitin recognition machinery required for selective autophagosome formation. Zymophagy is activated by experimental pancreatitis in genetically engineered mice and cultured pancreatic acinar cells and by acute pancreatitis in humans. Furthermore, zymophagy has pathophysiological relevance by controlling pancreatitis-induced intracellular zymogen activation and helping to prevent cell death. Together, these data reveal a novel selective form of autophagy mediated by the VMP1-USP9x-p62 pathway, as a cellular protective response.Fil: Grasso, Daniel Hector. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de Ciencias BiolĂłgicas. Cátedra de FisiopatologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Ropolo, Alejandro Javier. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de Ciencias BiolĂłgicas. Cátedra de FisiopatologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Lo RĂ©, Andrea Emilia. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de Ciencias BiolĂłgicas. Cátedra de FisiopatologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Boggio, VerĂłnica. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de Ciencias BiolĂłgicas. Cátedra de FisiopatologĂa; ArgentinaFil: Molejon, Maria Ines. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de Ciencias BiolĂłgicas. Cátedra de FisiopatologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Iovanna, Juan L.. Inserm; FranciaFil: Gonzalez, Claudio D.. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de Ciencias BiolĂłgicas. Cátedra de FisiopatologĂa; ArgentinaFil: Urrutia, RaĂşl. Mayo Clinic; Estados UnidosFil: Vaccaro, Maria Ines. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂmica. Departamento de Ciencias BiolĂłgicas. Cátedra de FisiopatologĂa; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
A mosaic of induced and non-induced branches promotes variation in leaf traits, predation and insect herbivore assemblages in canopy trees
Forest canopies are complex and highly diverse environments. Their diversity is
affected by pronounced gradients in abiotic and biotic conditions, including variation
in leaf chemistry. We hypothesised that branch-localised
defence induction
and vertical stratification in mature oaks constitute sources of chemical variation
that extend across trophic levels. To test this, we combined manipulation of plant
defences, predation monitoring, food-choice
trials with herbivores and sampling of
herbivore assemblages. Both induction and vertical stratification affected branch
chemistry, but the effect of induction was stronger. Induction increased predation
in the canopy and reduced herbivory in bioassays. The effects of increased predation
affected herbivore assemblages by decreasing their abundance, and indirectly,
their richness. In turn, we show that there are multiple factors contributing to
variation across canopies. Branch-localised
induction, variation between tree individuals
and predation may be the ones with particularly strong effects on diverse
assemblages of insects in temperate forests
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