Quantum Baker Maps for Spiraling Chaotic Motion

We define a coupling of two baker maps through a pi/2 rotation both in position and in momentum. The classical trajectories thus exhibit spiraling, or loxodromic motion, which is only possible for conservative maps of at least two degrees of freedom. This loxodromic baker map is still hyperbolic, that is, fully chaotic. Quantization of this map follows on similar lines to other generalized baker maps. It is found that the eigenvalue spectrum for quantum loxodromic baker map is far removed from those of the canonical random matrix ensembles. An investigation of the symmetries of the loxodromic baker map reveals the cause of this deviation from the Bohigas-Giannoni-Schmit conjecture

Trace elements accumulation in the sea lamprey along the major hydrographic basins of Portugal

Trace elements accumulation in the sea lamprey along the major hydrographic basins of Portuga

Real-time rheology of actively growing bacteria

The population growth of a Staphylococcus aureus culture, an active colloidal system of spherical cells, was followed by rheological measurements, under steady-state and oscillatory shear flows. We observed a rich viscoelastic behavior as a consequence of the bacteria activity, namely, of their multiplication and density-dependent aggregation properties. In the early stages of growth (lag and exponential phases), the viscosity increases by about a factor of 20, presenting several drops and full recoveries. This allows us to evoke the existence of a percolation phenomenon. Remarkably, as the bacteria reach their late phase of development, in which the population stabilizes, the viscosity returns close to its initial value. Most probably, this is caused by a change in the bacteria physiological activity and in particular, by the decrease of their adhesion properties. The viscous and elastic moduli exhibit power-law behaviors compatible with the "soft glassy materials" model, whose exponents are dependent on the bacteria growth stage. DOI: 10.1103/PhysRevE.87.030701

Rheo-NMR velocimetry characterisation of PBLG/m-cresol

NMR spectroscopy was used to characterise the velocity profile in nematic solutions of poly(gamma-benzyl-L-glutamate) (PBLG) in m-cresol during the application of a simple shear-flow at constant shear-rate values. In this study, the rheo-NMR technique was used that allows an insight over the fluid dynamics during the application of a shear flow in the presence of an external magnetic field, in a perpendicular direction to the shear gradient. Using this Magnetic Resonance Imaging (MRI) based technique, the velocity profile developed inside the system is accessed.info:eu-repo/semantics/publishedVersio

JC virus in the pathogenesis of colorectal cancer, an etiological agent or another component in a multistep process?

JCV infection occurs early in childhood and last throughout life. JCV has been associated to colorectal cancer and might contribute to the cancer phenotype by several mechanisms. Among JCV proteins, particularly two of them, large T-antigen and agnoprotein, can interfere with cell cycle control and genomic instability mechanisms, but other viral proteins might also contribute to the process. Part of viral DNA sequences are detected in carcinoma lesions, but less frequently in adenomas, and not in the normal surrounding tissue, suggesting they are integrated in the host cell genome and these integrations have been selected; in addition viral integration can cause a gene, or chromosomal damage. The inflammatory infiltration caused by a local chronic viral infection in the intestine can contribute to the selection and expansion of a tumor prone cell in a cytokine rich microenvironment. JCV may not be the cause of colorectal cancer, but it can be a relevant risk factor and able to facilitate progression at one or several stages in tumor progression. JCV transient effects might lead to selective expansion of tumor cells. Since there is not a direct cause and effect relationship, JCV infection may be an alternative to low frequency cancer predisposition genes

Three new cryptic species of the lamprey genus Lampetra Bonnaterre, 1788 (Petromyzontiformes: Petromyzontidae) from the Iberian Peninsula.

The Iberian Peninsula is a repository for biodiversity, presenting high levels of endemism in both plants and animals. In this peninsular region, brook lampreys confined to small, isolated river basins evolved in allopatry giving rise to evolutionary lineages, as revealed by mitochondrial DNA markers. For a better understanding of the taxonomic status and relationships of Iberian populations of the genus Lampetra, we combined previous data from genetics and morphological analysis (assessed here), and describe three new species of the lamprey genus Lampetra Bonnaterre, 1788 in Portugal. In this region L. planeri actually represent a complex of cryptic species, each having smaller geographic ranges than L. planeri, and consequently, greater vulnerability to extinction. The description of Lampetra alavariensis sp. nov. is based on 36 specimens collected on Ribeira de Mangas, a tributary of river Esmoriz, in Northern Portugal. Lampetra auremensis sp. nov. is described on the basis of 31 specimens collected on Ribeira do Olival, a small tributary of river Nabão (Tagus basin). Finally, Lampetra lusitanica sp. nov. is described based on 38 specimens from Ribeira da Marateca, Sado river basin, the southernmost distribution of the genus Lampetra. The recognition of these new species will contribute to the conservation of these already imperilled taxa and will help prevent the extinction of three important evolutionary lineages

Rheology of living cells

The mechanical behavior of living cells, during planktonic growth, has been thoroughly explored combining common biological techniques with rheology and rheo-imaging measurements. Under a shear flow, bacterial cultures of Staphylococcus aureus revealed a complex and rich rheological behavior not usually accessed in biological studies. In particular, in stationary shear flow, the viscosity increased during the exponential phase and returned close to its initial value at the late phase of growth, accompanied by the stabilization of the bacterial population. In oscillatory flow, the elastic and viscous moduli exhibited power-law behaviors whose exponents are dependent on the bacteria growth stage, and can be associated to a Soft Glassy Material behavior. These behaviors were framed in a microscopic model that suggests the formation of a dynamic web-like structure, where specific aggregation phenomena may occur, depending on growth stage and cell density. Furthermore, systematic measurements combining optical density and dry weight techniques presented new evidences, which confirmed that the observed cell aggregation patterns developed during growth, under shear, can not only be cell density dependent.info:eu-repo/semantics/publishedVersio

Validation of wireless sensors for psychophysiological studies

James One (MindProber Labs) is a wireless psychophysiological device comprising two sensors: one measuring electrodermal activity (EDA), the other photoplethysmography (PPG). This paper reports the validation of James One's EDA sensor by comparing its signal against a research grade polygraph. Twenty participants were instructed to perform breathing exercises to elicit the modulation of EDA and heart rate, while the physiological signal was captured simultaneously on James One and a Biopac MP36. The resulting EDA and PPG records collected from both systems were comprehensively compared. Results suggest that James One captures EDA signal with a quality comparable to a research grade equipment, this constituting a reliable means of capturing data while minimizing setup time and intrusiveness.P.S.M. was supported by an FCT fellowship grant (PhD-iHES program) with the reference PDE/BDE/113601/2015

Developments in fish telemetry

Freshwater and marine ecosystems continue to be the focus of significant environmental change associated with an expanding human population and a rapidly changing climate. Many organisms within these environments, and fish in particular, are susceptible to increasing pressures, ranging from exploitation to modifications and loss of habitat. In order to manage and conserve these populations and protect biodiversity, these resources must be managed in a sympathetic and responsible manner. One biological tool that is progressively at the cutting edge of aquatic conservation is telemetry, which is increasingly being used by scientists to investigate fundamental aspects of animal biology in order to conserve and manage natural resources. The Sixth Conference on Fish Telemetry held in Europe was organised by the University of Evora and the Institute of Oceanography of the Faculty of Sciences of the University of Lisbon in June 2005. The Conference attracted 162 delegates from 25 countries stimulating a multidisciplinary approach to problem solving and further promoting technological development and innovation in the field of wildlife telemetry. The Conference provided an excellent forum for scientists and engineers to exchange views and to disseminate information on recent developments in order to support and provide the scientific basis for the sustainable management of aquatic resources. At the conference 74 oral and 56 poster contributions presented, and after review by members of the editorial board, 26 manuscripts were selected for inclusion within these proceedings. The selected papers are organised into four sections: (1) Human Impacts and Fisheries; (2) Migration and Behaviour; (3) Species Conservation and Habitat Rehabilitation; (4) Methodology and New Technology. We would like to thank the support of two institutions for the organization of the Conference, the University of Évora and the Institute of Oceanography (Faculty of Sciences, University of Lisbon), as well as the sponsorship of Administração do Porto de Sines, Ambassade de France au Portugal, Bacalhôa wines of Portugal, British Council (Portugal), Câmara Municipal de Sesimbra, Direccão-Geral das Pescas e Aquicultura, Fundação Luso-Americana, Fundação para a Ciência e a Tecnologia, Instituto da Água, Instituto de Turismo de Portugal, Instituto Italiano di Cultura Lisboa, Oceaná rio de Lisboa, and Região de Turismo da Costa Azul. We would also like to thank the members of the Conference Secretariat, Scientific and Organizing Committees, and all the attendees for contributing directly or indirectly to the success of this event. Special thanks go to 68 independent referees for helping to peer-review and select the manuscripts for the proceedings