On the Aging Dynamics in an Immune Network Model

Recently we have used a cellular automata model which describes the dynamics of a multi-connected network to reproduce the refractory behavior and aging effects obtained in immunization experiments performed with mice when subjected to multiple perturbations. In this paper we investigate the similarities between the aging dynamics observed in this multi-connected network and the one observed in glassy systems, by using the usual tools applied to analyze the latter. An interesting feature we show here is that the model reproduces the biological aspects observed in the experiments during the long transient time it takes to reach the stationary state. Depending on the initial conditions, and without any perturbation, the system may reach one of a family of long-period attractors. The pertrubations may drive the system from its natural attractor to other attractors of the same family. We discuss the different roles played by the small random perturbations (noise) and by the large periodic perturbations (immunizations)

Young adults' preferences and satisfaction levels in Duty-free shopping in airports

This study aims to explore and understand what young adults’ duty free shoppers (18-26 years old) want and are getting from travel retail shopping on airport environments and to evaluate their satisfaction levels with the service. It has important managerial contributions since it is an important target in a fast growing market. An online survey was conducted with 188 young adults and its results show that young adults’ are somewhat satisfied with the overall service on duty free stores mainly in what concerns quality of the products and physical evidence of the stores. Results also show that the majority of buyers within this segment are price driven and strongly influenced by promotions associated with price reductions, and do not seem very satisfied with respect to that. Keywords: Youn

The pressor effect of angiotensin-(1-7) in the rat rostral ventrolateral medulla involves multiple peripheral mechanisms

OBJECTIVE: In the present study, the peripheral mechanism that mediates the pressor effect of angiotensin-(1-7) in the rostral ventrolateral medulla was investigated. METHOD: Angiotensin-(1-7) (25 pmol) was bilaterally microinjected in the rostral ventrolateral medulla near the ventral surface in urethane-anesthetized male Wistar rats that were untreated or treated (intravenously) with effective doses of selective autonomic receptor antagonists (atenolol, prazosin, methyl-atropine, and hexamethonium) or a vasopressin V1 receptor antagonist [d(CH2)5 -Tyr(Me)-AVP] given alone or in combination. RESULTS: Unexpectedly, the pressor response produced by angiotensin-(1-7) (16 ± 2 mmHg, n = 12), which was not associated with significant changes in heart rate, was not significantly altered by peripheral treatment with prazosin, the vasopressin V1 receptor antagonist, hexamethonium or methyl-atropine. Similar results were obtained in experiments that tested the association of prazosin and atenolol; methyl-atropine and the vasopressin V1 antagonist or methyl-atropine and prazosin. Peripheral treatment with the combination of prazosin, atenolol and the vasopressin V1 antagonist abolished the pressor effect of glutamate; however, this treatment produced only a small decrease in the pressor effect of angiotensin-(1-7) at the rostral ventrolateral medulla. The combination of hexamethonium with the vasopressin V1 receptor antagonist or the combination of prazosin, atenolol, the vasopressin V1 receptor antagonist and methyl-atropine was effective in blocking the effect of angiotensin-(1-7) at the rostral ventrolateral medulla. CONCLUSION: These results indicate that angiotensin-(1-7) triggers a complex pressor response at the rostral ventrolateral medulla that involves an increase in sympathetic tonus, release of vasopressin and possibly the inhibition of a vasodilatory mechanism

Immunization and Aging: a Learning Process in the Immune Network

The immune system can be thought as a complex network of different interacting elements. A cellular automaton, defined in shape-space, was recently shown to exhibit self-regulation and complex behavior and is, therefore, a good candidate to model the immune system. Using this model to simulate a real immune system we find good agreement with recent experiments on mice. The model exhibits the experimentally observed refractory behavior of the immune system under multiple antigen presentations as well as loss of its plasticity caused by aging.Comment: 4 latex pages, 3 postscript figures attached. To be published in Physical Review Letters (Tentatively scheduled for 5th Oct. issue

Inspecting zircon populations of the Iberian Pyrite Belt: tracking the Cadomian record of the South Portuguese Zone

AIMS OF THE MEETING: The scientific sessions will be focused on the Pan-African and Cadomian Orogenies recorded in North Africa and western Europe across the Ediacaran Cambrian transition and its bearing in the assembly and demise of Pannotia. Contributions dealing with structural, magmatic, provenance sources, palaeomagnetic, sedimentary, chronostratigraphic and radiometric constraints are particularly welcome. ORGANIZING COMMITTEE: J. Javier Álvaro, Instituto de Geociencias (CSIC-UCM), Spain Martim Chichorro, Universidade Nova de Lisboa, Portugal Gabriel Gutiérrez-Alonso, Universidad de Salamanca.ABSTRACT: The palaeogeographic location of the southernmost zone of the Iberian Massif, the South Portuguese Zone (SPZ), prior to the amalgamation of Pangaea is still a matter of debate. In this work, we attempt to track its palaeogeographic setting during the final stages of the Cadomian Cycle.info:eu-repo/semantics/publishedVersio

Aboriginal Women Against Violence Project Evaluation Report

In 2008 Joan Harrison’s Support Services for Women received funding under the National Community Crime Prevention Programme (NCCPP) in relation to the Aboriginal Women Against Violence Project. The overall aim of the project was ‘to address family violence in Aboriginal and Torres Strait Islander communities in Liverpool and Campbelltown areas’ (Attorney General’s Funding schedule). The project identified two specific strategies to achieve this general aim: to train local Aboriginal and Torres Strait Islander women to become trainer, mentors and advocates in their own communities;to establish an Aboriginal Women Against Violence Committee. This evaluation reports on the agreed outcomes identified in the funding agreement as well as identifying broader lessons arising from the project in relation to addressing violence in Aboriginal and Torres Strait Islander communities.Joan Harrison’s Support Services for Wome

Superficial sedimentary stocks and sources of carbon and nitrogen in coastal vegetated assemblages along a flow gradient

Coastal vegetated ecosystems are major organic carbon (OC) and total nitrogen (TN) sinks, but the mechanisms that regulate their spatial variability need to be better understood. Here we assessed how superficial sedimentary OC and TN within intertidal vegetated assemblages (saltmarsh and seagrass) vary along a flow gradient, which is a major driver of sediment grain size, and thus of organic matter (OM) content. A significant relationship between flow current velocity and OC and TN stocks in the seagrass was found, but not in the saltmarsh. OC and TN stocks of the saltmarsh were larger than the seagrass, even though that habitat experiences shorter hydroperiods. Mixing models revealed that OM sources also varied along the flow gradient within the seagrass, but not in the saltmarsh, showing increasing contributions of microphytobenthos (17-32%) and decreasing contributions of POM (45-35%). As well, OM sources varied vertically as microphytobenthos contribution was highest at the higher intertidal saltmarsh (48%), but not POM (39%). Macroalgae, seagrass and saltmarsh showed low contributions. Local trade-offs between flow current velocities, hydroperiod and structural complexity of vegetation must be considered, at both horizontal and vertical (elevation) spatial dimensions, for better estimates of blue carbon and nitrogen in coastal ecosystems.Foundation of Science and Technology of Portugal (FCT) PTDC/MAR-EST/3223/2014 UID/Multi/04326/2013 FCT UID/MAR/00350/2018 SFRH/BPD/119344/2016info:eu-repo/semantics/publishedVersio

Vertical intertidal variation of organic matter stocks and patterns of sediment deposition in a mesotidal coastal wetland

Tidal coastal wetlands, common home to seagrass and salt marshes, are relevant carbon sinks due to their high capacity to accumulate and store organic carbon in their sediments. Recent studies demonstrated that the spatial variability of this organic carbon within the same wetland system can be significant. Some of the environmental drivers of this spatial variability remain understudied and the selection of the most relevant ones can be context dependent. Here we investigated the role of bed elevation, hydrodynamics, and habitat type (salt marsh and seagrass) on the organic matter (OM) net deposition-resuspension rate and superficial sedimentary stocks (top 5 cm) at the tidal wetlands of the Ria Formosa, a mesotidal coastal lagoon in South Portugal. Results showed that two vectors of spatial variation need to be considered to describe the intertidal sedimentary OM stocks: the bed elevation that imposes a decrease of the hydroperiod and thus the change of habitat from the lower seagrass Z. noltei to the upper saltmarsh S. maritimus, and the horizontal spatial variation along the secondary channels of the lagoon that imposes a decrease in the current flow velocity magnitude. The multiple linear regression analyses, using data from 40 sampling points, explained 59% of the variation of the superficial sedimentary stocks of OM in salt marshes and seagrasses of the Ria Formosa lagoon and revealed that stocks generally decrease with elevation, yet with variation among sites and habitats. It was also found that the decrease of the OM net deposition-resuspension rate with bed elevation was exponential. Our study emphasizes the importance of considering multiple environmental drivers and spatial variation for regional estimations of organic matter (and organic carbon) sedimentary stocks in coastal wetlands.info:eu-repo/semantics/publishedVersio

Carbon and nitrogen stocks and burial rates in intertidal vegetated habitats of a Mesotidal coastal lagoon

Coastal vegetated ecosystems such as saltmarshes and seagrasses are important sinks of organic carbon (OC) and total nitrogen (TN), with large global and local variability, driven by the confluence of many physical and ecological factors. Here we show that sedimentary OC and TN stocks of intertidal saltmarsh (Sporobolus maritimus) and seagrass (Zostera noltei) habitats increased between two- and fourfold along a decreasing flow velocity gradient in Ria Formosa lagoon (south Portugal). A similar twofold increase was also observed for OC and TN burial rates of S. maritimus and of almost one order of magnitude for Z. noltei. Stable isotope mixing models identify allochthonous particulate organic matter as the main source to the sedimentary pools in both habitats (39–68%). This is the second estimate of OC stocks and the first of OC burial rates in Z. noltei, a small, fast-growing species that is widely distributed in Europe (41,000 ha) and which area is presently expanding (8600 ha in 2000s). Its wide range of OC stocks (29–99 Mg ha-1 ) and burial rates (15–122 g m2 y-1 ) observed in Ria Formosa highlight the importance of investigating the drivers of such variability to develop global blue carbon models. The TN stocks (7–11 Mg ha-1 ) and burial rates (2–4 g m-2 y-1 ) of Z. noltei were generally higher than seagrasses elsewhere. The OC and TN stocks (29–101 and 3–11 Mg ha-1 , respectively) and burial rates (19–39 and 3–5 g m-2 y-1 ) in S. maritimus saltmarshes are generally lower than those located in estuaries subjected to larger accumulation of terrestrial organic matter.DL57/2016/CP1361/CT0002; MinECo, MDM2015-0552info:eu-repo/semantics/publishedVersio

Purification, crystallization and preliminary X-ray diffraction analysis of the seryl-tRNA synthetase from Candida albicans

The seryl-tRNA synthetase (SerRS) from Candida albicans exists naturally as two isoforms resulting from ambiguity in the natural genetic code. Both enzymes were crystallized by the sitting-drop vapour-diffusion method using 3.2-3.4 M ammonium sulfate as precipitant. The crystals belonged to the hexagonal space group P6(1)22 and contained one monomer per asymmetric unit, despite the synthetase existing as a homodimer (with a molecular weight of ∼116 kDa) in solution. Diffraction data were collected to 2.0 Å resolution at a synchrotron source and the crystal structures of unliganded SerRS and of its complexes with ATP and with a seryl-adenylate analogue were solved by molecular replacement. The structure of C. albicans SerRS represents the first reported structure of a eukaryotic cytoplasmic SerRS.publishe