Nota sobre paleocorrentes na formação vermelha de Marco Furado (Península de Setúbal)

Empregou-se a análise de paleocorrentes, com o intuito de investigar a proveniência do material que constitui a formação vermelha de Marco Furado, descrita em trabalho anterior. Os resultados parecem confirmar as hipóteses aí postas, uma vez que apresentam certa zona da serra da Arrábida como centro emissor do mesmo material. Descreve-se também um achado de indústria lítica no mesmo depósito, o qual permite conferir-lhe um limite de idade máxima.info:eu-repo/semantics/publishedVersio

Evaluating the Neolithic expansion at both shores of the Mediterranean Sea

During the Neolithic, human populations underwent cultural and technological developments that led to an agricultural revolution. Although the population genetics and evolution of European Neolithic populations have been extensively studied, little is known regarding the Neolithic expansion in North Africa with respect to Europe. One could expect that the different environmental and geological conditions at both shores of the Mediterranean Sea could have led to contrasting expansions. In order to test this hypothesis, we compared the Neolithic expansion in Europe and North Africa accounting for possible migration between them through the Strait of Gibraltar. We analyzed the entire X chromosome of 580 individuals from 20 populations spatially distributed along the North of Africa and Europe. Next, we applied approximate Bayesian computation based on extensive spatially explicit computer simulations to select among alternative scenarios of migration through the Strait of Gibraltar and to estimate population genetics parameters in both expansions. Our results suggest that, despite being more technologically advanced, Neolithic populations did not expand faster than Paleolithic populations, which could be interpreted as a consequence of a more sedentary lifestyle. We detected reciprocal Neolithic migration between the Iberian Peninsula and North Africa through the Strait of Gibraltar. Counterintuitively, we found that the studied Neolithic expansions presented similar levels of carrying capacity and migration, and occurred at comparable speeds, suggesting a similar demic process of substitution of hunter–gatherer populations. Altogether, the Neolithic expansion through both Mediterranean shores was not so different, perhaps because these populations shared similar technical abilities and lifestyle patterns.Fundação para a Ciência e a Tecnologia | Ref. POCI-01-0145-FEDER-007274Fundação para a Ciência e a Tecnologia | Ref. SFRH/BD/97200/2013Fundação para a Ciência e a Tecnologia | Ref. IF/01262/2014Fundação para a Ciência e a Tecnologia | Ref. IF/00955/2014Ministerio de Economía y Competitividad | Ref. RYC-2015-18241Ministerio de Economía y Competitividad | Ref. CGL2013-44351-

From Bloch Oscillations to a Steady-State Current in Strongly Biased Mesoscopic Devices

It has long been known that quantum particles in a periodic lattice exhibit an oscillatory motion that is solely driven by a constant and uniform force field. In a strongly biased mesoscopic device, this would appear as an ongoing time-dependent current oscillation (a Bloch oscillation) but, even when electrons can move coherently and without scattering, a steady-state regime of charge transport (a Landauer current) have been seen to quickly emerge. Here, we theoretically investigate the non-equilibrium current dynamics of a strongly biased two-terminal mesoscopic device, in order to show that such a system can exhibit Bloch oscillations as a transient regime that relaxes into a Landauer steady-state from charge being drained into the leads. Analytical results from the one-dimensional Wannier-Stark ladder problem are combined with numerical quantum time-evolution of a tight-binding toy model with finite leads to characterize the decay times of transient Bloch oscillations and establish the conditions under which they can occur.Comment: Preliminary Version (13 pages + 12 Figures). Comments and Suggestions are Welcome

Chloride penetration into carbonated concrete

To ensure the durability of concrete structures it is necessary to understand its behaviour in the presence of aggressive agents. Carbonation and chloride action are the two leading causes of degradation in reinforced concrete structures.  Despite the combined action of these two mechanisms being a reality, there is little research on the effect of CO2 presence on the chloride behaviour in concrete. This work studies the total chlorides ingress into carbonated concrete. For this, samples with CEM I 42.5R were cast with 0.6 of water/binder ratio. After 90 days of the curing period, half of the samples were subjected to accelerated carbonation (20ºC, 55%Relative Humidity and 4%CO2) for 1 month. The other half was protected with a plastic film during the same period. Chloride immersion test, based on LNEC E390 (Portuguese specification), were performed with samples subjected to both experimental conditions. Afterwards, the depth of chlorides and CO2 penetration was evaluated. The results show that, for these conditions, the CO2 presence has a direct influence on chloride behaviour. The non-carbonated samples showed a profile with a higher amount of chloride than carbonated ones.Authors thank the foundation for science and technology (FCT) for supporting this research

Choosing the most effective pattern classification model under learning-time constraint

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Nowadays, large datasets are common and demand faster and more effective pattern analysis techniques. However, methodologies to compare classifiers usually do not take into account the learning-time constraints required by applications. This work presents a methodology to compare classifiers with respect to their ability to learn from classification errors on a large learning set, within a given time limit. Faster techniques may acquire more training samples, but only when they are more effective will they achieve higher performance on unseen testing sets. We demonstrate this result using several techniques, multiple datasets, and typical learning-time limits required by applications.Nowadays, large datasets are common and demand faster and more effective pattern analysis techniques. However, methodologies to compare classifiers usually do not take into account the learning-time constraints required by applications. This work presentsCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFUNDECT - FUNDAÇÃO DE APOIO AO DESENVOLVIMENTO DConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq [303182/2011-3, 477692/2012-5, 552559/2010-5, 481556/2009-5, 303673/2010-9, 470571/2013-6, 306166/2014-3, 311140/2014-9]CAPES [01-P-01965/2012]FAPESP [2011/14058-5, 2012/18768-0, 2007/52015-0, 2013/20387-7, 2014/16250-9]311140/2014-9; 303182/2011-3; 477692/2012-5; 552559/2010-5; 481556/2009-5; 303673/2010-9; 303182/2011-3; 470571/2013-6; 306166/2014-301-P-01965/20122011/14058-5, 2012/18768-0; 2007/52015-0; 2013/20387-7; 2014/16250-9sem informaçã

Impact of D0-D0bar mixing on the experimental determination of gamma

Several methods have been devised to measure the weak phase gamma using decays of the type B+- --> D K+-, where it is assumed that there is no mixing in the D0-D0bar system. However, when using these methods to uncover new physics, one must entertain the real possibility that the measurements are affected by new physics effects in the D0-D0bar system. We show that even values of x_D and/or y_D around 10^{-2} can have a significant impact in the measurement of sin^2{gamma}. We discuss the errors incurred in neglecting this effect, how the effect can be checked, and how to include it in the analysis.Comment: 18 pages, Latex with epsfig, 8 figure

Novel 3-hydroxy-4-pyridinonato oxidovanadium(IV) complexes to investigate structure/activity relationships

A previous evaluation of the insulin-like activity of three 3-hydroxy-4-pyridinonato oxidovanadium(IV) complexes raised questions about structure/activity relationships, namely the influence of the hydrophilic/lipophilic balance of the complex and the capacity of the ligand to stabilize the +4 oxidation state of vanadium ion, on achieving an positive effect. To address these questions, we synthesized six new oxidovanadium(IV) complexes with variable hydrophilic/lipophilic balance, obtained by introducing different substituents on the nitrogen atom, and used two 3-hydroxy-4-pyrones as starting reagents to provide methyl and ethyl groups in the ortho position of the ring. For the new and previously reported complexes, we studied the oxidation–reduction properties and insulin-like activity in terms of inhibitory effect on Free fatty acid (FFA) release in isolated rat adipocytes. The results obtained show that only one of the complexes, Bis(3-hydroxy-1(H)-2-methyl-4-pyridonato)oxidovanadium(IV), VO(mpp)2, exhibits a significantly greater capacity to inhibit FFA release than VOSO4 and consequently is worthy to be considered for further studies. The establishment of structure activity relationships was not attainable but this study brings new information about the influence of some properties of the compounds on the achievement of an insulin-like effect. The results reveal that: (i) the oxidation–reduction cycles of the complexes are identical; (ii) the presence of more lipophilic substituents on the nitrogen atom does not enhance insulin-like properties; (iii) a high solubility in water proved to be not sufficient for a positive activity in inhibiting FFA release; (iv) a small molecular size may be an important property for reaching the right targets.info:eu-repo/semantics/publishedVersio

Low-cost/high-precision smart power supply for data loggers

This paper presents a low-cost/high-precision smart power supply for application on data loggers. The microprocessor unit is the brain of the system and manages the events and was optimized to provide electrical energy to the electronic devices under normal operation and under the presence of disruptive events. The measurements showed that when switching either from battery to AC or from AC to battery, neither caused the shutdown of the power supply nor affected the behavior of the power supply. The power supply was able to charge 80% of the battery on a fast recharge of 1 h and the remaining 20% on a slow recharge of 2 h. The current allocated to the battery did not affect the operation of the power supply. The tests also showed that the power supply was able to transmit relevant information about its operation to external computers through a serial connection. This information includes the voltages at the battery and at the output of the voltage regulators, the voltage level of the AC network, the level of the battery charge and if it was being recharged, the current being drained, the internal temperatures at two locations (one measured on the resistor that limits battery charge and another measured on the output diode of the regulators), and whether the cooling system is being used. The total cost of this smart power supply is less than $150, demonstrating good potential for its popularization.This work was partially supported by FCT national funds, under the national support to R&D units grant, through the reference project UIDB/04436/2020 and UIDP/04436/2020. This research was also partially supported by the FAPESP agency (Fundação de Amparo à Pesquisa do Estado de São Paulo) through the project with the reference 2019/05248-7. Professor João Paulo Carmo was support by a PQ scholarship with the reference CNPq 304312/2020-7

A estação arqueológica das Boucinhas, Regueira, Vitorino de Piães, Ponte de Lima (Norte de Portugal)

Publicam-se os resultados das sondagens arqueológicas realizadas no povoado da Idade do Bronze da Boucinha, em Vitorino de Piães, Ponte de Lima.Projeto FCT: The Entre-Douro-e-Minho landscape since middle of 3rd to the end of 2nd millenia BC.info:eu-repo/semantics/publishedVersio

What can we learn from a measurement of sin(2 beta + gamma)?

The constraints on the value of the CKM phase gamma that may be achieved by prospective measurements of sin(2 beta) and sin(2 beta + gamma) are discussed. Significant constraints require quite small errors, and may depend on assumptions about strong phases. The measurement of sin(2 beta + gamma) combined with other experiments could provide valuable limits on new physics in Bd-Bdbar mixing.Comment: 10 pages, 7 figures, RevTex 4, uses amsmath and graphic