Phase transition and critical end point driven by an external magnetic field in asymmetric quark matter

The location of the critical end point (CEP) in the QCD phase diagram is determined under different scenarios. The effect of strangeness, isospin/charge asymmetry and an external magnetic field is investigated. The discussion is performed within the 2+1 flavor Nambu--Jona-Lasinio model with Polyakov loop. It is shown that isospin asymmetry shifts the CEP to larger baryonic chemical potentials and smaller temperatures. At large asymmetries the CEP disappears. However, a strong enough magnetic field drives the system into a first order phase transition.Comment: 7 pages, 3 figures; PRD versio

The QCD critical end point driven by an external magnetic field in asymmetric quark matter

The effect of the isospin/charge asymmetry and an external magnetic field in the location of the critical end point (CEP) in the QCD phase diagram is investigated. By using the 2+1 flavor Nambu--Jona-Lasinio model with Polyakov loop (PNJL), it is shown that the isospin asymmetry shifts the CEP to larger baryonic chemical potentials and smaller temperatures, and in the presence of a large enough isospin asymmetry the CEP disappears. Nevertheless, a sufficiently high external magnetic field can drive the system into a first order phase transition again.Comment: Contribution to the "20th Particles and Nuclei International Conference" (PANIC 14), Hamburg, Germany, 25-29 August 201

The Role of the Cephalopod Digestive Gland in the Storage and Detoxification of Marine Pollutants

COST Action FA1301 "A network for improvement of cephalopod welfare and husbandry in research, aquaculture and fisheries (CephsInAction)" The Portuguese Foundation for Science and Technology (FCT) MARE through the strategic programme (UID/MAR/04292/2013; SFRH/BD/109462/2015; IF/00265/2015) GreenTech (PTDC/MARBIO/0113/2014) FCTThe relevance of cephalopods for fisheries and even aquaculture, is raising concerns on the relationship between these molluscs and environmental stressors, from climate change to pollution. However, how these organisms cope with environmental toxicants is far less understood than for other molluscs, especially bivalves, which are frontline models in aquatic toxicology. Although, sharing the same basic body plan, cephalopods hold distinct adaptations, often unique, as they are active predators with high growth and metabolic rates. Most studies on the digestive gland, the analog to the vertebrate liver, focused on metal bioaccumulation and its relation to environmental concentrations, with indication for the involvement of special cellular structures (like spherulae) and proteins. Although the functioning of phase I and II enzymes of detoxification in molluscs is controversial, there is evidence for CYP-mediated bioactivation, albeit with lower activity than vertebrates, but this issue needs yet much research. Through novel molecular tools, toxicology-relevant genes and proteins are being unraveled, from metallothioneins to heat-shock proteins and phase II conjugation enzymes, which highlights the importance of increasing genomic annotation as paramount to understand toxicant-specific pathways. However, little is known on how organic toxicants are stored, metabolized and eliminated, albeit some evidence from biomarker approaches, particularly those related to oxidative stress, suggesting that these molluscs' digestive gland is indeed responsive to chemical aggression. Additionally, cause-effect relationships between pollutants and toxicopathic effects are little understood, thus compromising, if not the deployment of these organisms for biomonitoring, at least understanding how they are affected by anthropogenically-induced global change.publishersversionpublishe

Mineralogical and petrographic characterization of Preguiça and Vila Ruiva mines

This study was performed on the Preguiça and Vila Ruiva mines and aimed at petrographic and mineralogical characterization of various geological media. The Preguiça and Vila Ruiva mines are two examples of the different types of Zn-Pb(-Ag-Sb-Au) deposits that occur in the Ossa Morena Zone, more specifically in the Moura-Ficalho region. Both deposits are in Serra da Preguiça, Beja district, and were explored for Fe-Zn-Pb in the early 20th century and between 1960 and 1966. In Preguiça and Vila Ruiva mines, the old exploration mainly targeted supergene enrichment areas, and information available on the primary mineralisation is scarce. The geology of the Preguiça-Vila Ruiva mining area consists of carbonate rocks that are affected by significant hydrothermal alteration (dolomitization and chertification), essentially composed of dolomite, calcite, and minor ankerite. Recent studies suggest that the Preguiça and Vila Ruiva deposits correspond to very rich secondary Zn-ores located in metadolostones of Lower Cambrian age due to strong in situ oxidation and supergene enrichment processes on previous sulphide mineralisation. Rock samples were collected from the gossans and the host rocks in the spring of 2022. In addition, local soil was sampled from the first 15cm of the soil profile. All rock and soil samples collected from Preguiça and Vila Ruiva were analysed by x-ray diffraction (XRD) and the host rock specimens were further studied using a petrographic microscope. The study of the Preguiça and Vila Ruiva thin sections suggests that the host rocks correspond to dolomitic meta-limestones manly with granoblastic texture, composed of dolomite, calcite, quartz, and opaque minerals. For the Preguiça mine, XRD shows that the dolomitic metalimestone has average dolomite contents of ~30%, while Vila Ruiva shows significantly higher contents (~80%) of this mineral. The Preguiça gossan is characterized by significant amounts of willemite (~52%), quartz (~40%), and iron oxides (goethite, hematite, and minor magnetite). Accessory minerals include chalcophanite and anglesite. At Vila Ruiva, the gossan is dominated by iron oxides, manly magnetite (~33%) and minor hematite (~17%) and goethite (~12%). In this mine, mineral phases such as willemite, chalcophanite and anglesite were not identified. The soils of Vila Ruiva present slightly higher amounts of quartz and lower contents of carbonate minerals than Preguiça soils. However, smithsonite (~12%) was only identified for Vila Ruiva, while cerussite (~3%) was identified only for Preguiça. Hematite is the most abundant iron oxide in the soils of both mines. Although the results suggest some differences in the gossans mineralogy of both mines, the small number of samples analysed largely justify further investigation

Uncertainty on multi-objective optimization problems

In general, parameters in multi-objective optimization are assumed as deterministic with no uncertainty. However, uncertainty in the parameters can affect both variable and objective spaces. The corresponding Pareto optimal fronts, resulting from the disturbed problem, define a cloud of curves. In this work, the main objective is to study the resulting cloud of curves in order to identify regions of more robustness and, therefore, to assist the decision making process. Preliminary results, for a very limited set of problems, show that the resulting cloud of curves exhibits regions of less variation, which are, therefore, more robust to parameter uncertainty.The authors would like to thank FCT - Fundacao para a Ciencia e a Tecnologia (Portuguese Foundation for Science and Technology) that supported in part this work

Stochastic algorithms assessment using performance profiles

Optimization with stochastic algorithms has become a relevant approach, specially, in problems with complex search spaces. Due to the stochastic nature of these algorithms, the assessment and comparison is not straightforward. Several performance measures have been proposed to overcome this difficulty. In this work, the use of performance profiles and an analysis integrating a trade-off between accuracy and precision are carried out for the comparison of two stochastic algorithms. Traditionally, performance profiles are used to compare deterministic algorithms. This methodology is applied in the comparison of two stochastic algorithms - genetic algorithms and simulated annealing. The results highlight the advantages and drawbacks of the proposed assessment.The authors would like to thank FCT - Fundacao para a Ciencia e a Tecnologia (Portuguese Foundation for Science and Technology) that supported in part this wor

A Transcriptomic Approach to the Recruitment of Venom Proteins in a Marine Annelid

CEECIND/02699/2017The growing number of known venomous marine invertebrates indicates that chemical warfare plays an important role in adapting to diversified ecological niches, even though it remains unclear how toxins fit into the evolutionary history of these animals. Our case study, the Polychaeta Eulalia sp., is an intertidal predator that secretes toxins. Whole-transcriptome sequencing revealed proteinaceous toxins secreted by cells in the proboscis and delivered by mucus. Toxins and accompanying enzymes promote permeabilization, coagulation impairment and the blocking of the neuromuscular activity of prey upon which the worm feeds by sucking pieces of live flesh. The main neurotoxins ("phyllotoxins") were found to be cysteine-rich proteins, a class of substances ubiquitous among venomous animals. Some toxins were phylogenetically related to Polychaeta, Mollusca or more ancient groups, such as Cnidaria. Some toxins may have evolved from non-toxin homologs that were recruited without the reduction in molecular mass and increased specificity of other invertebrate toxins. By analyzing the phylogeny of toxin mixtures, we show that Polychaeta is uniquely positioned in the evolution of animal venoms. Indeed, the phylogenetic models of mixed or individual toxins do not follow the expected eumetazoan tree-of-life and highlight that the recruitment of gene products for a role in venom systems is complex.publishersversionpublishe

Evolutionary Insights into IL17A in Lagomorphs

In leporids, IL17A had been implicated in the host defense against extracellular pathogens, such as Francisella tularensis that infects hares and rabbits and causes the zoonotic disease tularemia. Here, we studied IL17A from five lagomorphs, European rabbit, pygmy rabbit, brush rabbit, European brown hare, and American pika. We observed that this protein is highly conserved between these species, with a similarity of 97-99% in leporids and ~88% between leporids and American pika. The exon/intron structure, N-glycosylation sites, and cysteine residues are conserved between lagomorphs. However, at codon 88, one of the interaction sites between IL17A and its receptor IL17RA, there is an Arg>Pro mutation that only occurs in European rabbit and European brown hare. This could induce critical alterations in the IL17A structure and conformation and consequently modify its function. The differences observed between leporids and humans or rodents might also represent important alterations in protein structure and function. In addition, as for other interleukins, IL17A sequences of human and European rabbit are more closely related than the sequences of human and mouse or European rabbit and mouse. This study gives further support to the hypothesis that European rabbit might be a more suitable animal model for studies on human IL17.FCT and North Portugal Regional Operational Programme 2007/2013 (ON.2) grants supported this work

Simulation of Delamination Propagation in Composites Under High-Cycle Fatigue by Means of Cohesive-Zone Models

A damage model for the simulation of delamination propagation under high-cycle fatigue loading is proposed. The basis for the formulation is a cohesive law that links fracture and damage mechanics to establish the evolution of the damage variable in terms of the crack growth rate dA/dN. The damage state is obtained as a function of the loading conditions as well as the experimentally-determined coefficients of the Paris Law crack propagation rates for the material. It is shown that by using the constitutive fatigue damage model in a structural analysis, experimental results can be reproduced without the need of additional model-specific curve-fitting parameters

Simulation of Delamination Under High Cycle Fatigue in Composite Materials Using Cohesive Models

A new thermodynamically consistent damage model is proposed for the simulation of high-cycle fatigue crack growth. The basis for the formulation is an interfacial degradation law that links Fracture Mechanics and Damage Mechanics to relate the evolution of the damage variable, d, with the crack growth rate da/dN. The damage state is a function of the loading conditions (R and (Delta)G) as well as the experimentally-determined crack growth rates for the material. The formulation ensures that the experimental results can be reproduced by the analysis without the need of additional adjustment parameters