6,436 research outputs found
The Influence of oral environment on diet choices in goats: a focus on saliva protein composition
There is ample evidence that ruminants are capable of making choices between
different foods that provide a more balanced diet that would be obtained by eating at
random. In the particular case of goats, they occupy a diversity of habitats and different
breeds present variability of feeding behaviors resultant from adaptations to the existent
plant species. In their food search activity, individuals are faced with variable amounts of
plant secondary metabolites (PSMs), which may present some toxic and anti-nutritional
effects depending on the individual’s ability to deal with it.
The oral cavity has a key role in the recognition and decision processes of ingestion
or rejection. In this chapter we will first consider how goats identify foods and behave
according to the food items available. Focus will be done on the importance of taste sense
in this process and the information available on the main structures involved in taste
detection and perception in goats will be reviewed. In a second section we will focus on
the characteristics of goat’s saliva, particularly in terms of their protein composition,
presenting results obtained by our research team
Correction to: Northerly wind trends along the Portuguese marine coast since 1950
All figure captions are not accurate. Also, there is a repeated error in most figures because the vertical scales incorrectly show Wind Strenght instead of Wind Strength and in Fig. 4 (mid-panel) 2003 instead of 2004.info:eu-repo/semantics/publishedVersio
Accretion and activity on the post-common-envelope binary RR~Cae
Current scenarios for the evolution of interacting close binaries - such as
cataclysmic variables (CVs) - rely mainly on our understanding of low-mass star
angular momentum loss (AML) mechanisms. The coupling of stellar wind with its
magnetic field, i.e., magnetic braking, is the most promising mechanism to
drive AML in these stars. There are basically two properties driving magnetic
braking: the stellar magnetic field and the stellar wind. Understanding the
mechanisms that drive AML therefore requires a comprehensive understanding of
these two properties. RRCae is a well-known nearby (d=20pc) eclipsing DA+M
binary with an orbital period of P=7.29h. The system harbors a metal-rich cool
white dwarf (WD) and a highly active M-dwarf locked in synchronous rotation.
The metallicity of the WD suggests that wind accretion is taking place, which
provides a good opportunity to obtain the mass-loss rate of the M-dwarf
component. We analyzed multi-epoch time-resolved high-resolution spectra of
RRCae in search for traces of magnetic activity and accretion. We selected a
number of well-known activity indicators and studied their short and long-term
behavior. Indirect-imaging tomographic techniques were also applied to provide
the surface brightness distribution of the magnetically active M-dwarf, and
reveals a polar feature similar to those observed in fast-rotating solar-type
stars. The blue part of the spectrum was modeled using a atmosphere model to
constrain the WD properties and its metal enrichment. The latter was used to
improve the determination of the mass-accretion rate from the M-dwarf wind. The
presence of metals in the WD spectrum suggests that this component arises from
accretion of the M-dwarf wind. A model fit to the WD gives Teff=(7260+/-250)K
and logg=(7.8+/-0.1) dex with a metallicity of =(-2.8+/-0.1)dex,
and a mass-accretion rate of dotMacc=(7+/-2)x1e-16Msun/yr.Comment: 14 pages, 7 Figures, 6 Table
Globalization trends and regional development - dynamics of FDI and human capital flows
This is a post-peer-review, pre-copyedit version of an article published in [European Journal of Development Research]. The definitive publisher-authenticated version [European Journal of Development Research 26, 160-161 (January 2014)] is available online at: http://www.palgravejournals.com/ejdr/journal/v26/n1/full/ejdr201354a.htmlApparently rendered irrelevant by globalization, regions have been rediscovered as a force in economic and social development by both scholars and policymakers. Localized inter-personal ties and networks are seen as important resources (Woolcock and Narayan, 2000), and the local supply of entrepreneurs has emerged as a key determinant of future economic growth (Chatterji et al, 2013)
Mutual information rate and bounds for it
The amount of information exchanged per unit of time between two nodes in a
dynamical network or between two data sets is a powerful concept for analysing
complex systems. This quantity, known as the mutual information rate (MIR), is
calculated from the mutual information, which is rigorously defined only for
random systems. Moreover, the definition of mutual information is based on
probabilities of significant events. This work offers a simple alternative way
to calculate the MIR in dynamical (deterministic) networks or between two data
sets (not fully deterministic), and to calculate its upper and lower bounds
without having to calculate probabilities, but rather in terms of well known
and well defined quantities in dynamical systems. As possible applications of
our bounds, we study the relationship between synchronisation and the exchange
of information in a system of two coupled maps and in experimental networks of
coupled oscillators
The impact of the cytoskeleton dynamics on immune responses
Immune cells are susceptible to a variety of external stimuli that triggers cell surface receptors, leading to activation of intracellular proteins and changes in the actin cytoskeleton. The Rho-GTPases are a family of proteins that regulate several aspects of actin polymerization. They take part in an intricate network of other proteins and can therefore have a direct or indirect role in several cell functions.
In this study I aimed to define the role of the Rho-GTPases Cdc42 and Rac2, as well as the effector proteins WASp and N-WASp in the adaptive immune system.
In paper I the aim was to dissect the particular contribution of WASp-deficiency to the induction of skin pathology in Wiskott-Aldrich syndrome patients, using mouse models. Our study showed that WASp-deficient dendritic cells accumulate in the skin; were able to induce an increase in cross-presentation of exogenous antigen and therefore increased CD8+ T cell proliferation and activation in vivo and in vitro. This was caused by increased expression of Rac2 in the cytoplasm, which regulates the phagosomal pH and promotes loading of antigen on MHC class I molecules.
In paper II we aimed to understand the role of Cdc42 for B cell activation using a mouse where we deleted Cdc42 conditionally in mature B cells. Mice with Cdc42-deficient B cells showed reduced marginal zone and follicular B cell numbers. Immunized mice had reduced germinal center B cells associated with reduced specific antibody titers in serum. In vitro assays revealed less spreading on antibody-coated surfaces and a skewed CD4+ T cell activation towards more production of IFN and less IL-2.
In paper III we studied the combined contribution of WASp and N-WASp deficiency in B cells. A WASp KO mouse where N-WASp was conditionally deleted only in B cells (cDKO) was used. Compared to WT and WASp KO mice, the cDKO mouse had a large reduction in marginal zone B cells as well as decreased marginal zone B cell precursors and follicular B cells. B cells in cDKO mice also failed to mount a specific antibody response to both T- dependent and T-independent antigens with reduced specific antibody titers, together with decreased antigen uptake by marginal zone B cells and transportation to the follicle.
In paper IV we investigated the effect of the hyperactive mutated WASp, found in X-linked neutropenia patients, on murine B and T cells. XLN-WASp mutations induced increased polymerized actin in both T and B cells. We detected reduced spreading but normal chemotaxis toward specific chemokines by both cell types. We also observed reduced proliferation of B cells but not T cells and increased apoptosis of both cell types in vitro. The latter is probably due to increased genomic instability in B and T cells as observed by a FISH-telomere assay.
Altogether, this study shows that Rho GTPases and their effector proteins are crucial for correct cell function and the cellular and humoral immune responses. Notably, the phenotypic severity can be increased by depletion of closely related intracellular proteins suggesting the existence of compensatory mechanisms and overlapping roles. The characterization of the Rho GTPases function may contribute to more precise interventions and therapeutic success
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