22,893 research outputs found

    Quantifying “Transitional” Soil Behaviour

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    The last decade has seen an increasing amount of research on so called “transitional” soils that are characterised by incomplete convergence to unique normal compression lines and/or critical state lines in simple laboratory tests. This topic has often provoked reaction, perhaps because some have seen it as a challenge to critical state frameworks of soil behaviour. A particular issue is whether incomplete testing or other test defects might cause such an apparent behaviour. Confusion around the topic has not been helped by the wide range of degrees of convergence seen for different materials and differences seen between convergence in compression and shearing. This paper proposes a unifying means of plotting laboratory test data from such soils that will hopefully provide a rational framework for such discussions, since it makes explicit the degree of convergence towards unique volumetric states for different forms of loading. Data are examined for three “transitional” soils. The results show that bringing about convergence for these soils would require strains beyond those that may easily be applied and that the lack of convergence cannot solely be an artefact of test defects. Plastic volumetric strain was found to cause much faster convergence than plastic shear strain

    Antimicrobial activity of essential oils of Lamiaceae aromatic spices towards sheep mastitis-causing Staphylococcus aureus and Staphylococcus epidermidis

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    Mastitis in ewes is responsible for massive economic losses. Antibiotics are routinely used for mastitis control but its excessive use leads to development of antibiotic resistance with deleterious outcomes both for animal and public health. Essential oils (EOs) show antibacterial proprieties and no resistance has been reported after prolonged exposure; however their efficacy depends on their chemical composition. In this study EOs chemical composition from four autochthonous aromatic herbs, from Alentejo region, southern Portugal, Calamintha nepeta subsp. nepeta, Lavandula stoechas subsp. luisieri, Rosmarinus oficinalis and Thymus mastichina was accessed. EOs of R. officinalis showed predominance in monoterpene hydrocarbons (63%) whereas EOs of T. mastichina, L. luisieri and C. nepeta were rich in oxygenated monoterpenes (71-95%). The antimicrobial activity of selected EOs was investigated towards Staphylococcus aureus (n= 24) and Staphylococcus epidermidis isolates (n= 24) from ovine mastitic milk origin. Results of disk diffusion assay revealed that C. nepeta, L. stoechas and T. mastichina EOs are highly active against both S. aureus and S. epidermidis strains, whereas R. officinalis EO is highly active against S. aureus strains but inactive against several S. epidermidis isolates. EOs concentration causing bacterial growth inhibition ranged from 500 to 4,000 µg mL-1 in liquid microassays

    Iguais ou diferentes? Cuidados de saúde materno-infantil a uma população de imigrantes

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    Os concelhos de Amadora e Sintra constituem um território de fortes características de identidade na Área Metropolitana de Lisboa que resultam, entre outros aspectos, da elevada densidade populacional (sobretudo Amadora), do marcado crescimento na última década (sobr etudo Sintra, onde a população residente aumentou cerca de 40% entre 1991 e 2001) e, principalmente, da sua diversidade social, cultural e étnica. D e facto, a proporção de imigrantes nestes concelhos atinge um dos v alores mais elevados do país. A equidade na pr estação de cuidados tem sido demonstrada como factor de r edução das disparidades na saúde que determina a morbilidade e a mortalidade decorrentes da assimetria das populações. Na Unidade de Saúde D (Hospital Fernando Fonseca e 9 Centr os de Saúde da Amadora e Sintra), não tinha ainda sido desenvolvida uma investigação científica estruturada sobre os níveis de saúde e o acesso e utilização dos serviços e que sustentem políticas ajustadas às vulnerabilidades deste grupo. Este conhecimento possibilita a reorganização dos serviços de cuidados de saúde e é fundamental para (r e)pensar processos de planeamento e modelos de inter venção que culminem numa integração de sucesso para o século XXI.info:eu-repo/semantics/publishedVersio

    Preclinical modeling of chronic inhibition of the Parkinson's disease associated kinase LRRK2 reveals altered function of the endolysosomal system in vivo

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    The most common mutation in the Leucine-rich repeat kinase 2 gene (LRRK2), G2019S, causes familial Parkinson's Disease (PD) and renders the encoded protein kinase hyperactive. While targeting LRRK2 activity is currently being tested in clinical trials as a therapeutic avenue for PD, to date, the molecular effects of chronic LRRK2 inhibition have not yet been examined in vivo. We evaluated the utility of newly available phospho-antibodies for Rab substrates and LRRK2 autophosphorylation to examine the pharmacodynamic response to treatment with the potent and specific LRRK2 inhibitor, MLi-2, in brain and peripheral tissue in G2019S LRRK2 knock-in mice. We report higher sensitivity of LRRK2 autophosphorylation to MLi-2 treatment and slower recovery in washout conditions compared to Rab GTPases phosphorylation, and we identify pS106 Rab12 as a robust readout of downstream LRRK2 activity across tissues. The downstream effects of long-term chronic LRRK2 inhibition in vivo were evaluated in G2019S LRRK2 knock-in mice by phospho- and total proteomic analyses following an in-diet administration of MLi-2 for 10 weeks. We observed significant alterations in endolysosomal and trafficking pathways in the kidney that were sensitive to MLi-2 treatment and were validated biochemically. Furthermore, a subtle but distinct biochemical signature affecting mitochondrial proteins was observed in brain tissue in the same animals that, again, was reverted by kinase inhibition. Proteomic analysis in the lung did not detect any major pathway of dysregulation that would be indicative of pulmonary impairment. This is the first study to examine the molecular underpinnings of chronic LRRK2 inhibition in a preclinical in vivo PD model and highlights cellular processes that may be influenced by therapeutic strategies aimed at restoring LRRK2 physiological activity in PD patients

    Furthering the Application of Machine Learning to the Prediction of Oceanic Plankton Biomass

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    The Plankton Prediction System (PPS) is a joint project between the Computer Science and Zoology departments of the University of Cape Town. Its purpose is to research and develop machine-learning software capable of predicting the level and distribution of subsurface oceanic chlorophyll, given related data. In so doing the PPS provides marine biologists with valuable information that would otherwise be both time-consuming and expensive to retrieve. The work outlined in this paper furthers earlier research [9] by Fenn, Curtis and Oberholzer and, as well as addressing a few shortcomings, expands upon a number of topics that demanded closer investigation. The following five items were chosen by the 2006 project team as core research areas: 1. The production of a more structured and coherent set of data from which to perform predictions. 2. The effect of various clustering algorithms on depth profile data. 3. The use of a dynamic Bayesian network to incorporate the effect of time on chlorophyll predictions. 4. The use of topic maps as a means to dynamically display the relationship between data. 5. A greater degree of accompanying documentation and modular design. It is best to think of the work outlined in this paper as three stages in a pipeline. The first stage, preprocessing, is responsible for the integration of all the raw data from a number of different sources. After integration, the data is further discretized through a clustering process, which reduces its complexity. The second stage, prediction, is responsible for training a Dynamic Bayesian Network (DBN) with the clustered data produced in the preprocessing stage. Once training is complete, absent sub-surface chlorophyll data is inferred from the resultant network. The final stage in the PPS pipeline concerns itself with the visualization of the results obtained from both the preprocessing and prediction stages. Technologies, such as Topic Maps and hypergraphs are implemented to create a dynamic view of the relationship between data. Moreover, inference results are rendered as colour rasters for viewing within the web-based PPS interface

    Fabric characterisation in transitional soils

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    A “transitional” mode of soil behaviour implies that dense and loose samples do not converge towards the same volumes within the strains and stresses applied by simple oedometer and triaxial tests. As this behaviour involves soils with different gradings and mineralogies (e.g. gap graded, well graded and/or mixed mineralogies), identifying the factors responsible is difficult. Nevertheless, it has been previously speculated that strong forms of fabric that are difficult to break down as strains and stresses are applied, might be the common cause. This paper aims at investigating some elements of fabric at the microscale of transitional soils. A gap graded and two well graded mixtures with large amounts of non-plastic fines were investigated by oedometer and triaxial tests. As it would be difficult to identify experimentally many commonly used elements of fabric in these soils, e.g. the contact network, mercury intrusion porosimetry (MIP) was used as a first step to characterise the evolution of pore size distributions (PSDs) of dense and loose samples undergoing the same stress paths, using the PSDs as a proxy of fabric. Multi-directional bender element testing was performed to confirm the isotropy of the elastic stiffness, from which it might be inferred that the fabric is also isotropic. Statistical parameters of the PSDs were calculated, the changes of which were related to the evolution of macroscale void ratios. The robust fabrics causing lack of convergence were characterised by a complex evolution of the PSDs, the initial differences of which could not be erased during conventional testing. This work also provided a simple method to examine the fabric of particularly well graded or gap graded materials, for which other techniques, such as CT or SEM, could not reveal the multi- scale nature of the fabric

    Stiff person syndrome presenting with sudden onset of shortness of breath and difficulty moving the right arm: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>First described in 1956, stiff person syndrome is characterized by episodes of slowly progressive stiffness and rigidity in both the paraspinal and limb muscles. Although considered a rare disorder, stiff person syndrome is likely to be under-diagnosed due to a general lack of awareness of the disease in the medical community.</p> <p>Case presentation</p> <p>A 27-year-old Hispanic woman presented to our emergency department with a sudden onset of shortness of breath and difficulty moving her right arm. Her physical examination was remarkable in that her abdomen was firm to palpation and her right upper extremity was rigid on passive and active ranges of motion. Her right fingers were clenched in a fist. Her electromyography findings were consistent with stiff person syndrome in the right clinical setting. Stiff person syndrome is confirmed by testing for the anti-glutamic acid decarboxylase antibody. Her test for this was positive.</p> <p>Conclusion</p> <p>Stiff person syndrome may not be a common condition. However, if disregarded in the differential diagnosis, it can lead to several unnecessary tests being carried out causing a delay in treatment. This case report reveals some of the characteristic features of stiff person syndrome with an atypical presentation.</p
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