Some properties of two Nambu--Jona-Lasinio -type models with inputs from lattice QCD

We investigate the phase diagram of the so-called Polyakov--Nambu--Jona-Lasinio (PNJL) model at finite temperature and nonzero chemical potential. The calculations are performed in the light and strange quark sectors ($u$, $d$, $s$), which includes the 't Hooft instanton induced interaction term that breaks the axial symmetry, and the quarks are coupled to the (spatially constant) temporal background gauge field. On one hand, a special attention is payed to the critical end point (CEP). The strength of the flavor-mixing interaction alters the CEP location, since when it becomes weaker the CEP moves to low temperatures and can even disappear. On the other hand, we also explore the connection between QCD, a nonlocal Nambu--Jona-Lasinio type model and the Landau gauge gluon propagator. Possible links between the quenched gluon propagator and low energy hadronic phenomenology are investigated.Comment: Contribution to the International Meeting "Excited QCD", Peniche, Portugal, 06 - 12 May 201

Tools for online collaboration: do they contribute to improve teamwork?

In the last decades, the fast growth of Information and Communication Technologies changed our way to communicate and share information. Traditional groups or teams frequently give way to virtual teams, working with tools for online collaboration. Interaction between persons geographically dispersed has become easier. However, the use of new collaboration tools can also bring many challenges. Some technologies, like e-mail, can create delays on reply or even misunderstandings, case the message is not well understood by the recipient. Can these new technologies improve the productivity and enhance the creativity between group members, improving also their confidence and motivation? Although virtual teams have a high capacity to adapt to constant market changes, personal interactions are still important, mainly to clarify tasks and goals. The main purpose of this study is to understand how tools for online collaboration may improve the productivity (and enhance creativity) in teamwork. This study was conducted through an internet platform and the survey was hosted online by SurveyMonkey.com. We intended to verify, among other questions, what users think about different collaboration tools, how often they use these tools, and how they perceive these technologies as adequate ways to communicate, to work with, and to improve productivity. Findings show that e-mail is the most used tool, and personal contact is still more important for teamwork than any tools for online collaboration. Our results contribute to perceive in what extent collaboration tools are indeed an asset or a barrier in teamwork.info:eu-repo/semantics/publishedVersio

Response surface design to study the influence of inoculum, particle size and inoculum to substrate ratio on the methane production from Ulex sp.

Ulex europaeus is one of the world worst invaders vegetal species and its suitability for biogas production is significant. The effect of three factors affecting the Biochemical Methane Potential (BMP, expressed as volume of CH4 per mass of volatile solids of waste) and the biodegradability rate (k, expressed in volume of CH4 per mass of VS and time) of U. europaeus was assessed by a Central Composite Face Centred Design. The BMP varied from 153 L kg1 to 308 L kg1. Inoculum to substrate ratio (ISR) and the type of inoculum had high influence on the final results. k varied from 14 L kg1 d1 to 49 L kg1 d1. The conditions that simultaneously maximized the BMP and k were an inoculum consisting in 55% (v) of granular sludge and 45 % (v) of suspended sludge from a sludge digester, an ISR of 4 g g1, and a particle size of 1.9 mm. Considering the average biomass production in shrub land areas, the potential energy production from U. europaeus is estimated in (36.9 ± 19.3) GJ ha1 yr1. For example, in Europe, a maximum energy supply of 7 EJ yr1 could be achieved from potentially harvestable shrub land areas.The authors acknowledge the financial support of the Portuguese Science Foundation (FCT) and European Social Fund (ESF, POPH-QREN) through the grant given to José Carlos Costa (SFRH/BDP/48962/2008), and through the project FCOMP-01-0124-FEDER-027914 (PTDC/AAG-TEC/3048/2012), financed by FEDER through COMPETE e Programa Operacional Factores de Competitividade; and FCT Strategic Project PEst-OE/EQB/LA0023/2013, the FCT Project RECI/BBB-EBI/0179/2012 and the Project “BioEnv e Biotechnology and Bioengineering for a sustainable world”, REF. NORTE-07-0124-FEDER-000048, co-funded by the Programa Operacional Regional do Norte (ON.2 e O Novo Norte), QREN, FEDER

How to develop financial applications with game features in e-banking?

As for Gamification, it is about business software with game characteristics, understanding the software development process will improve the practices, and will more than likely, improve the business itself (make it more efficient, effective, and less costly and mainly collect a positive influence from the customers). This study aims to develop a framework that provides the mechanisms to ensure that the software will have game characteristic and that clients will recognize it as Gamification. Our results show that the five-step framework proposal applied to the Gamification project management on this study, the Spiral development model, and the group discussion results into a positive effect on customers and e-business. The spiral development methodology used for the development of this application showed to be the appropriated for this type of project. The tests with discussion-groups proved to be a key "tool" to identify and adapt the game characteristics that has led to the improvement of customer perception of socialness, usefulness ease of use, enjoyment and ease of use that probed to have a strong positive impact on the intention to use the game.info:eu-repo/semantics/acceptedVersio

Design of experiments to assess pre-treatment and co-digestion strategies that optimize biogas production from macroalgae Gracilaria vermiculophylla

A design of experiments was applied to evaluate different strategies to enhance the methane yield of macroalgae Gracilaria vermiculophylla. Biochemical Methane Potential (BMP) of G. vermiculophylla after physical pre-treatment (washing and maceration) reached 481 ± 9 L CH4 kg−1 VS, corresponding to a methane yield of 79 ± 2%. No significant effects were achieved in the BMP after thermochemical pre-treatment, although the seaweeds solubilisation increased up to 44%. Co-digestion with glycerol or sewage sludge has proved to be effective for increasing the methane production. Addition of 2% glycerol (w:w) increased the BMP by 18%, achieving almost complete methanation of the substrate (96 ± 3%). Co-digestion of seaweed and secondary sludge (15:85%, TS/TS) increased the BMP by 25% (605 ± 4 L CH4 kg−1 VS) compared to the seaweed individual digestion.The authors acknowledge the financial support of the Portuguese Science Foundation (FCT) and European Social Fund (ESF, POPH-QREN) through the grant given to Jose Carlos Costa (SFRH/BDP/48962/2008), and through the projects: FCOMP-01-0124-FEDER-027914 (PTDC/AAG-TEC/3048/2012), financed by FEDER through COMPETE - Programa Operacional Factores de Competitividade; and FCT Strategic Project PEst- OE/EQB/LA0023/2013, the FCT Project RECI/BBB-EBI/0179/2012 and the Project "BioEnv Biotechnology and Bioengineering for a sustainable world'', REF. NORTE-07-0124-FEDER-000048, co-funded by the Programa Operacional Regional do Norte (ON. 2 - O Novo Norte), QREN, FEDER. We would like to thank Dr. Rui Pereira (Algaplus), for providing the seaweed samples

Optimization of biogas production from Sargassum sp. using a design of experiments to assess the co-digestion with glycerol and waste frying oil

A Design of Experiments was adopted to assess the optimal conditions for methane production from the macroalgae Sargassum sp. co-digested with glycerol (Gly) and waste frying oil (WFO). Three variables were tested:% total solids of algae (%TSSargassumsp.), co-substrate concentration (gGly/WFO L-1); and, co-substrate type (Gly or WFO). The Biochemical Methane Potential (BMP) of Sargassum sp. was 181±1 L CH4 kg-1 COD. The co-digestion with Gly and WFO increased the BMP by 56% and 46%, respectively. The methane production rate (k), showed similar behaviour as the BMP, increasing 38% and 19% with Gly and WFO, respectively. The higher BMP (283±18 L CH4 kg-1 COD) and k (65.9±2.1 L CH4 kg-1 COD d-1) was obtained in the assay with 0.5% TS and 3.0 gGly L-1. Co-digestion with glycerol or WFO is a promising process to enhance the BMP from the macroalgae Sargassum sp.The authors acknowledge the financial support of the Portuguese Science Foundation (FCT) and European Social Fund (ESF, POPH-QREN) through the grant given to JoseCarlos Costa (SFRH/BDP/48962/2008), and through the project FCOMP-01-0124FEDER-027914 (PTDC/AAG-TEC/3048/2012), financed by FEDER through COMPETE -Programa Operacional Factores de Competitividade; and FCT Strategic Project PEst-OE/EQB/LA0023/2013, the FCT Project RECI/BBB-EBI/0179/2012 and the Project "BioEnv - Biotechnology and Bioengineering for a sustainable world'', REF. NORTE-07-0124-FEDER-000048, co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER

Influence of inoculum, particle size and inoculum-substrate ratio on CH4 production from Ulex sp.

The performance of Anaerobic Digestion (AD) of solids wastes is affected by several factors. Most of them are related to each other. Currently, publish studies about AD only care about the individual influence of these variables, discarding possible interaction. A response surface experimental design was used to determine the most important variables and possible interactions – influence of inoculum type (anaerobic suspended sludge and granula sludge), Ulex sp. particle diameter (dp) and inoculum to substrate ratio (ISR) – on the Biochemical Methane Potential (BMP) and the maximum initial methane production rate (k). BMP and k of Ulex sp. varied between 153-308 L CH4 kg-1 VS and 14-49 L CH4 kg-1 VS d-1, respectively. Higher ISR and a mixture of granular and suspended sludge had a positive effect on the biodegradability of waste. A dp of 1.85 mm were defined as the optimal condition to simultaneously maximize the BMP and k

Evaluation of different strategies to maximize biogas production from algae

Seaweeds (macroalgae) are a promising substrate for biogas production due to the high percentage of carbohydrates and high growth rate. Therefore, the biogas produced from the anaerobic digestion of seaweeds is a sustainable and renewable alternative source of bioenergy. Seaweeds are available in coastal areas and may also be produced in aquacultures. This work presents results of the biochemical methane potential (BMP) of the wild seaweed, Gracilaria vermiculophylla, as well as the effect of physical and thermochemical pre-treatments on their biodegradability. The codigestion with glycerol and sewage sludge was also studied. The BMP of G. vermiculophylla after a physical pre-treatment (washing and maceration) reached 481±9 L CH4 kg-1 VS, corresponding to a methane yield of 79±2%. Regarding the thermochemical pre-treatments, it was found that the increase of temperature (from 20 to 90ºC), NaOH concentration (from 0.1 to 0.5 g NaOH per g TS) and pressure (from 1 to 6 bar) caused an increase in the seaweeds solubilisation up to 44%. However, the subsequent methane production was not increased as expected, although a faster methane production rate was observed. The co-digestion of G. vermiculophylla with glycerol or sewage sludge has proved to be quite effective for increasing the methane production. Addition of 2% glycerol (w:w) increased the methane production by 18% (599±16 L CH4 kg-1 VS) and methane yield by 22%, achieving almost complete substrate methanation. Moreover, the codigestion of seaweed and secondary sludge (15:85%, TS/TS) caused an increase of 25% in the BMP (605 ± 4 L CH4 kg-1 VS), relatively to the individual digestion of algae. The addition of glycerol in this assay did not cause significant improvements