95 research outputs found

    Gathering Abundance: An Exploration of Urban Foraging Practices in Toronto

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    This paper explores different urban foraging practices within Toronto aiming to understand the motivations for foraging within an urban centre, how this is enacted, and how the context of Toronto affects this practice. As an emerging field of study, there are few articles directly about urban foraging, but a wide body of literature which informs the topic. Seventeen semi-structured interviews were conducted, two with land managers, three with land managers/foragers, and twelve with foragers while walking through greenspaces in Toronto. The themes that emerged from the interviews were those of forager identity, environmental stewardship, (re)connection from nature, and private property, laws and transgression. Through foraging practices in the city people are able to interact with public greenspaces, and become participants within ecological and social communities. Eating weedy species and distinctions between native and introduced species heavily influence foraging practice. The embodied process of this work through harvesting and utilizing the plant materials creates a strong sense of connection to local seasonal cycles and food systems. Decisions to transgress bylaws are grounded in different notions of the role of nature and public spaces in the city. There is the potential for foraging practices to be part of sustainable and dynamic urban ecologies

    AN INFORMATION DATA BASE OF GEODETIC SERVICES ENGINEERING INVESTMENTS - THE IDEA OF DATA ORGANISATION

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    The goal of the project, being run by the Institute of Applied Geodesy of the Warsaw University of Technology, is to create a prototype database of building structures, which are typical from the point of view of the tasks of engineering geodesy.The database is expected to be available through the Internet and is planned to be filled with the information collected from surveying companies, which would like to present their realizations both from owners and users of engineering structures.Examples of modern solutions in the area of geodetic services for engineering investments realization is supposed to create a base for changes in the methods of teaching and presenting these issues at the Faculty of Geodesy and Cartography of the Warsaw University of Technology and at other Faculties interested in such problems

    Increased apoptosis of peripheral blood mononuclear cells in patients with perennial allergic asthma/rhinitis: relation to serum markers of apoptosis.

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    BACKGROUND: The goal of our study was to examine spontaneous and stimulated apoptosis of peripheral blood MNC from allergic patients, sensitized to Der p I antigen as compared to cells from non-atopic subjects. Furthermore we aimed to investigate which populations of mononuclear cells (lymphocytes, monocytes) undergo the apoptosis and to determine relations between apoptosis and serum levels of sFas/APO-1, ICE/caspase-1 or TNF-alpha. METHODS: The study included 17 patients with perennial, allergic asthma and/or allergic rhinitis [6 male and 11 female; mean age 29,5 years; (range 15-49)]. Apoptosis was assessed by fluorescence technique and confirmed by flow-cytometric method and DNA ladder. Serum levels of sFas, ICE/caspase-1 or TNF-alpha were determined by immunoassays (ELISA). RESULTS: Apoptotic index of unfractionated mononuclear cells (MNC) and lymphocytes (but not monocytes) were significantly higher in allergic patients as compared to non-allergic subjects after 48 and 72 hours of culture (p<0.05). Incubation of cells with ConA (10 microg/ml) resulted in a significant increase in the proportion of apoptotic cells in all populations once the apoptotic index for MNC and lymphocytes (but not monocytes) was again significantly higher in allergic as compared to non-allergic subjects after 24, 48 and 72 hour of culture. In allergic patients, mean serum sFas level, was significantly lower then in non-allergic group (mean value 624.8 pg/ml +/- 25.67 versus 802.0 pg/ml +/- 31.91; p = 0.003) and in both groups sFas level correlated inversely with apoptosis of MNC. The mean ICE/caspase-1 concentration was significantly higher in sera of allergic patients as compared to non-allergic group (mean value 27.71 pg/ml +/- 3.79 vs 23.54 pg/ml respectively; p<0.01). ICE/caspase-1 levels in allergic patients correlated with apoptotic index of mononuclear cells (r = 0.57; p<0.001). CONCLUSIONS: An increased spontaneous and mitogen-induced apoptosis of MNC from peripheral blood of atopic patients as well as different serum levels of sFas and ICE/caspase-1 correlating with apoptosis, suggest different regulation of apoptotic process in peripheral blood mononuclear cells of patients with allergic asthma and/or rhinitis

    Intrinsic membrane properties determine hippocampal differential firing pattern in vivo in anesthetized rats

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    The hippocampus plays a key role in learning and memory. Previous studies suggested that the main types of principal neurons, dentate gyrus granule cells (GCs), CA3 pyramidal neurons, and CA1 pyramidal neurons, differ in their activity pattern, with sparse firing in GCs and more frequent firing in CA3 and CA1 pyramidal neurons. It has been assumed but never shown that such different activity may be caused by differential synaptic excitation. To test this hypothesis, we performed high-resolution whole-cell patch-clamp recordings in anesthetized rats in vivo. In contrast to previous in vitro data, both CA3 and CA1 pyramidal neurons fired action potentials spontaneously, with a frequency of ∼3–6 Hz, whereas GCs were silent. Furthermore, both CA3 and CA1 cells primarily fired in bursts. To determine the underlying mechanisms, we quantitatively assessed the frequency of spontaneous excitatory synaptic input, the passive membrane properties, and the active membrane characteristics. Surprisingly, GCs showed comparable synaptic excitation to CA3 and CA1 cells and the highest ratio of excitation versus hyperpolarizing inhibition. Thus, differential synaptic excitation is not responsible for differences in firing. Moreover, the three types of hippocampal neurons markedly differed in their passive properties. While GCs showed the most negative membrane potential, CA3 pyramidal neurons had the highest input resistance and the slowest membrane time constant. The three types of neurons also differed in the active membrane characteristics. GCs showed the highest action potential threshold, but displayed the largest gain of the input-output curves. In conclusion, our results reveal that differential firing of the three main types of hippocampal principal neurons in vivo is not primarily caused by differences in the characteristics of the synaptic input, but by the distinct properties of synaptic integration and input-output transformation

    Proper Layering Is Important for Precisely Timed Activation of Hippocampal Mossy Cells

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    The mammalian cortex exhibits a laminated structure that may underlie optimal synaptic connectivity and support temporally precise activation of neurons. In ‘reeler' mice, the lack of the extracellular matrix protein Reelin leads to abnormal positioning of cortical neurons and disrupted layering. To address how these structural changes impact neuronal function, we combined electrophysiological and neuroanatomical techniques to investigate the synaptic activation of hippocampal mossy cells (MCs), the cell type that integrates the output of dentate gyrus granule cells (GCs). While somatodendritic domains of wild-type (WT) MCs were confined to the hilus, the somata and dendrites of reeler MCs were often found in the molecular layer, where the perforant path (PP) terminates. Most reeler MCs received aberrant monosynaptic excitatory input from the PP, whereas the disynaptic input to MCs via GCs was decreased and inhibition was increased. In contrast to the uniform disynaptic discharge of WT MCs, many reeler cells discharged with short, monosynaptic latencies, while others fired with long latencies over a broad temporal window in response to PP activation. Thus, disturbed lamination results in aberrant synaptic connectivity and altered timing of action potential generation. These results highlight the importance of a layered cortical structure for information processin

    Deuteron production in central Pb + Pb collisions at 158-A-GeV

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    Experimental results on deuteron emission from central Pb+Pb collisions (E_beam=158A GeV, fixed target), obtained by NA49 at the CERN SPS accelerator, are presented. The transverse mass m_t distribution was measured near mid-rapidity (2.0<y<2.5) in the range of 0<m_t-m_0<0.9 GeV/c2 (0<p_t<2.0 GeV/c) for the 4% most central collisions. An exponential fit gives an inverse slope T_d=(450ą30) MeV and a yield dN_d/dy=0.34ą0.03. The coalescence factor B2(m_t=m_0)=(3.5ą1.0)ˇ10^4 GeV^2 and its m_t-dependence are determined and discussed in terms of a model that includes the collective expansion of the source created in a collision. The derived Gaussian size parameter R_G of the emission volume is consistent with earlier HBT results on the source of pion emission

    Hadronic Expansion Dynamics in Central Pb+Pb Collisions at 158 GeV per Nucleon

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    Two-particle correlation functions of negative hadrons over wide phase space, and transverse mass spectra of negative hadrons and deuterons near mid-rapidity have been measured in central Pb+Pb collisions at 158 GeV per nucleon by the NA49 experiment at the CERN SPS. A novel Coulomb correction procedure for the negative two-particle correlations is employed making use of the measured oppositely charged particle correlation. Within an expanding source scenario these results are used to extract the dynamic characteristics of the hadronic source, resolving the ambiguities between the temperature and transverse expansion velocity of the source, that are unavoidable when single and two particle spectra are analysed separately. The source shape, the total duration of the source expansion, the duration of particle emission, the freeze-out temperature and the longitudinal and transverse expansion velocities are deduced

    The NA49 large acceptance hadron detector

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    The NA49 detector is a wide acceptance spectrometer for the study of hadron production in p+p, p+A, and A+A collisions at the CERN SPS. The main components are 4 large volume TPCs for tracking and particle identification via dE/dxdE/dx. TOF scintillator arrays complement particle identification. Calorimeters for transverse energy determination and triggering, a detector for centrality selection in p+A collisions, and beam definition detectors complete the set-up. A description of all detector components is given with emphasis on new technical realizations. Performance and operational experience are discussed in particular with respect to the high track density environment of central Pb+Pb collisions
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