5,431 research outputs found

    Geomorphological insight into changing tectonic regime, Pasinler Basin, Turkey

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    The Pasinler Basin, in the East Anatolian Contractional Province, features a suite of geomorphological zones, visible in the field, air photographs and Landsat and SRTM DEM imagery. These zones reflect past and current tectonically influenced processes. Collins et al: Geomorphological insight into changing tectonic regime, Pasinler Basin, Turkey. 2 of 26 Remnants of the Erzurum-Kars plateau representing Mio-Pliocene volcanism, associated with transtensional tectonics, have been modified by two stages of drainage development: an earlier, shallow valley network, which was modified following uplift and tilting to form the present system characterised by deep narrow valleys that supply alluvial fan complexes. These fans discharge onto the present, aggradation-dominated basin floor. Initial normal faulting induced massive slope failures on the basin’s northern margin. This extensional phase within the basin was reversed by the Late Pleistocene, with thrust faults modifying and producing landforms, and affecting sediment sequences, along both the north and south basin margins. The shift from a transtensional regime and associated volcanism to normal faulting in the Pliocene-Early Pleistocene, and then to the present compression-dominated regime appears to correspond with regional tectonic changes resulting from collision of the Arabian microplate and the subsequent westward movement of the Anatolian microplate

    Colloquy

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    At present, our system of criminal law administration has a considerable Rube Goldberg quality to it. Once the system decides to imprison a particular defendant--if we except from the generalization the couple of states that recently changed their laws in fundamental respects--the judge naturally asks himself what will happen when this man goes to prison. The answer is that the convicted offender will sit in prison for as long as the parole board wants him to. The judge must next consider whether any constraints exist on the parole board\u27s decisions on when to release people from prison. In a third of the statutory sentences the judge can specify that the defendant must remain imprisoned for up to one third or one half of the time to which he is sentenced. The question then becomes how long the judge wants a particular defendant to stay in prison. He knows that a nine-year sentence will mean minimum parole eligibility after three years,and that the parole board releases prisoners on their first eligibility date in eighty-five percent of the cases. Therefore, judges purpose-fully inflate sentences to discount for their knowledge that the parole board decreases the sentences which a judge imposes

    Out of the Shadows: A Young Woman\u27s Journey from Hiding to Celebrating her Identity

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    In April 2019 the UK government reported that little progress had been made to remedy social outcomes inequality between Roma and the wider population, recommending further recognition of Roma, for example in census data, to enable identification of Roma, their needs, and how to meet those needs. In this article we present an account of one Roma woman’s journey from hiding her identity to celebrating it. We expose five critical incidents that challenge and mould her sense of identity and career aspiration, with insights into her hopes and dreams as she reflects upon the barriers she faces and attempts to overcome. The narrative enhances understanding of the intersection of experience and ethnic identity formation, Marcella’s (pseudonym) case study emerges verbatim through quotes; we do not alter or correct her English. In our exploration, we follow the six classical steps recommended in case study analysis (Yin, 2009) and ground some of the key analytical concepts in Goffman’s theories of stigma (1963) and theatrical performances in everyday life. We conclude by identifying key parallels in her experience, relevant regardless of socioeconomic status to further debate on the nature of internalised shame, stigma, and class

    Treatment of malignant tumors of the skull base with multi-session radiosurgery

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    <p>Abstract</p> <p>Objective</p> <p>Malignant tumors that involve the skull base pose significant challenges to the clinician because of the proximity of critical neurovascular structures and limited effectiveness of surgical resection without major morbidity. The purpose of this study was to evaluate the efficacy and safety of multi-session radiosurgery in patients with malignancies of the skull base.</p> <p>Methods</p> <p>Clinical and radiographic data for 37 patients treated with image-guided, multi-session radiosurgery between January 2002 and December 2007 were reviewed retrospectively. Lesions were classified according to involvement with the bones of the base of the skull and proximity to the cranial nerves.</p> <p>Results</p> <p>Our cohort consisted of 37 patients. Six patients with follow-up periods less than four weeks were eliminated from statistical consideration, thus leaving the data from 31 patients to be analyzed. The median follow-up was 37 weeks. Ten patients (32%) were alive at the end of the follow-up period. At last follow-up, or the time of death from systemic disease, tumor regression or stable local disease was observed in 23 lesions, representing an overall tumor control rate of 74%. For the remainder of lesions, the median time to progression was 24 weeks. The median progression-free survival was 230 weeks. The median overall survival was 39 weeks. In the absence of tumor progression, there were no cranial nerve, brainstem or vascular complications referable specifically to CyberKnife<sup>® </sup>radiosurgery.</p> <p>Conclusion</p> <p>Our experience suggests that multi-session radiosurgery for the treatment of malignant skull base tumors is comparable to other radiosurgical techniques in progression-free survival, local tumor control, and adverse effects.</p

    Signal Propagation in Feedforward Neuronal Networks with Unreliable Synapses

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    In this paper, we systematically investigate both the synfire propagation and firing rate propagation in feedforward neuronal network coupled in an all-to-all fashion. In contrast to most earlier work, where only reliable synaptic connections are considered, we mainly examine the effects of unreliable synapses on both types of neural activity propagation in this work. We first study networks composed of purely excitatory neurons. Our results show that both the successful transmission probability and excitatory synaptic strength largely influence the propagation of these two types of neural activities, and better tuning of these synaptic parameters makes the considered network support stable signal propagation. It is also found that noise has significant but different impacts on these two types of propagation. The additive Gaussian white noise has the tendency to reduce the precision of the synfire activity, whereas noise with appropriate intensity can enhance the performance of firing rate propagation. Further simulations indicate that the propagation dynamics of the considered neuronal network is not simply determined by the average amount of received neurotransmitter for each neuron in a time instant, but also largely influenced by the stochastic effect of neurotransmitter release. Second, we compare our results with those obtained in corresponding feedforward neuronal networks connected with reliable synapses but in a random coupling fashion. We confirm that some differences can be observed in these two different feedforward neuronal network models. Finally, we study the signal propagation in feedforward neuronal networks consisting of both excitatory and inhibitory neurons, and demonstrate that inhibition also plays an important role in signal propagation in the considered networks.Comment: 33pages, 16 figures; Journal of Computational Neuroscience (published
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