Thermalization through Hagedorn states - the importance of multiparticle collisions

Quick chemical equilibration times of hadrons within a hadron gas are explained dynamically using Hagedorn states, which drive particles into equilibrium close to the critical temperature. Within this scheme master equations are employed for the chemical equilibration of various hadronic particles like (strange) baryon and antibaryons. A comparison of the Hagedorn model to recent lattice results is made and it is found that for both Tc =176 MeV and Tc=196 MeV, the hadrons can reach chemical equilibrium almost immediately, well before the chemical freeze-out temperatures found in thermal fits for a hadron gas without Hagedorn states.Comment: 8 pages, 3 figures, talk presented at the International Conference on Strangeness in Quark Matter, Buzios, Rio de Janeiro, Brazil, Sept. 27 - Oct. 2, 200

Prirnary gold rnineralisations in north of Portugal: some reflexions

[Resumo] Desde tempos pré-romanos que jazigos primários de ouro no norte de Portugal tem sido alvo de explora~6es de maior ou menor envergadura. Os jazigos sao do tipo filoniano e podem ser dominantemente quartzosos ou mais complexos. Os fi16es, sao sub-verticais e com direc~6es que se distribuem por vários grupos, ocorrem em diferentes contextos geológicos e espacialmente associados a zonas de cisalhamento dúctil (D3). Porém embora as estruturas filonianas estejam instaladas em fracturas, na su maioria relacionadas com D3 o essencial do seu preenchimento é mais tardio e sofreu diversos episódios de deforma~ao frágil. Com base nas associa~6es minerais presentes é possivel definir, do ponto de vista quimico-mineralógico, tres tipos principais de mineraliza95es. O ouro e o electrum tem, no essencial, urna expressao tardia, nomeadamente em rela~ao aos sulfuretos principais apresentando-se em fracturas, nos limites intergranulares e em cavidades destes minerais e do quartzo. As similitudes das diferentes ocorrencias no que respeita asua estrutura, textura e mineralogia principal sugere urna única época metalogénica aurífera. A existencia de exemplos em que fi16es cortam quer granitos biotiticos tardi-tectónicos (Grovelas), quer metas-sedimentos do Estefaniano B-C (Valongo) leva-nos a considerá-los como pós-D3 o que é corroborado pelo facto de existir, na maioria dos casos, urna associa~ao espacial estreita também com falhas tardias NIOE a N40E (D4). Apesar de se considerar que o essencial da deposi~ao da mineraliza~aoaurífera é tardia ela resultou de um processo langa como o comprova a complexidade das associa~6es quimico-mineralógicas definidas.[Abstract] Since pre-roman times primary gold ore deposits in north of Portugal have been more or less exploited. The deposits belong, essentially, to the vein type and they can be dominantly quartzic or even more complexo Veins are subvertical and with several groups of directions, occurring in different geological settings and spatial1y associated to ductil shear zones (D3). However, although the veins structures are placed in fractures, mosdy related to D3 (intrawestephalian in age) , the essential of the vein fil1ing is posterior and suffered several episodes of fragil deformation. Based on the mineral associations present, it is possible to define, three types of mineralisations on the chemical-mineralogical point of view. Gold and electrum have, in its éssential, a late expression, special1y on what concerns the main sulphides occurring in fractures in intergranular limits and in cavities of these minerals and quartz. The similarities of the different occurrences concerning their structure, texture and mineralogy suggest an unique gold metal10genic epoch. The existence of cases in which veins crosscut both late-tectonic biotite granites (Grovelas) and metasediments of Stephanian B-C age (Valongo) leads us to consider them as postD3, which is stressed by the existance of a close spatial association with late faults stricking NIOE to N40E (D4). Alt~ough the essential of gold deposition in considered to be later in time, it carne out from a long during process, proved by the complexity of the defined chemical-mineralogical associations

Particle Ratios and the QCD Critical Temperature

We show how the measured particle ratios at RHIC can be used to provide non-trivial information about the critical temperature of the QCD phase transition. This is obtained by including the effects of highly massive Hagedorn resonances on statistical models, which are used to describe hadronic yields. Hagedorn states are relevant close to $T_c$ and have been shown to decrease $\eta/s$ to the KSS limit and allow for quick chemical equilibrium times in dynamical calculations of hadrons. The inclusion of Hagedorn states creates a dependence of the thermal fits on the Hagedorn temperature, $T_H$, which is assumed to be equal to $T_c$, and leads to an overall improvement of thermal fits. We find that for Au+Au collisions at RHIC at $\sqrt{s_{NN}}=200$ GeV the best square fit measure, $\chi^2$, occurs at $T_c \sim 176$ MeV and produces a chemical freeze-out temperature of 170.4 MeV and a baryon chemical potential of 27.8 MeV.Comment: 6 pages, 2 figures, talk presented at the International Conference on Strangeness in Quark Matter, Buzios, Rio de Janeiro, Brazil, Sept. 27 - oct. 2, 200

Emerging (Bio)Sensing Technology for Assessing and Monitoring Freshwater Contamination - Methods and Applications

Ecological Water Quality - Water Treatment and ReuseWater is life and its preservation is not only a moral obligation but also a legal requirement. By 2030, global demands will exceed more than 40 % the existing resources and more than a third of the world's population will have to deal with water shortages (European Environmental Agency [EEA], 2010). Climate change effects on water resources will not help. Efforts are being made throughout Europe towards a reduced and efficient water use and prevention of any further deterioration of the quality of water (Eurostat, European Comission [EC], 2010). The Water Framework Directive (EC, 2000) lays down provisions for monitoring, assessing and classifying water quality. Supporting this, the Drinking Water sets standards for 48 microbiological and chemical parameters that must be monitored and tested regularly (EC, 1998). The Bathing Water Directive also sets concentration limits for microbiological pollutants in inland and coastal bathing waters (EC, 2006), addressing risks from algae and cyanobacteria contamination and faecal contamination, requiring immediate action, including the provision of information to the public, to prevent exposure. With these directives, among others, the European Union [EU] expects to offer its citizens, by 2015, fresh and coastal waters of good quality