1,074 research outputs found

    Improvements in vortex flow control design to increase sewer network flood resistance

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    Copyright © 2013 IWA7th International Conference on Sewer Processes and Networks (SPN7), Sheffield, UK, 28-30 August 2013Flow controls are used within the water industry to manage the flow through sewer networks by attenuating flows at convenient or critical locations. Many sewer networks, regardless whether the systems have a flow control installed, are predicted to become stressed in the future due to the effects of climate change, population growth and urbanisation. This issue is compounded by the age of the Britain’s sewerage infrastructure as well as the cost and difficulty of replacing and upgrading the infrastructure. Statutory ‘Catchment Flood Management Plans’ have been introduced within the United Kingdom to tackle this issue by better understanding the flow path of flood water on a catchment scale. This paper discusses a method to maximise the use of the current sewerage infrastructure by installing flow controls, meaning a greater volume of the sewer network can be used for stormwater storage. This paper continues by describing a method of increasing a sewer network’s flood resistance by using vortex flow controls with a lower design flow-rate compared to an orifice plate. This paper then concludes by describing three case studies demonstrating the use vortex flow controls when retrofitting sewer networks as well as the impact of implementing the retrofit design method.EPSRCSTREAM IDCHydro Internationa

    The Rho GDI Rdi1 regulates Rho GTPases by distinct mechanisms

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    © 2008 by The American Society for Cell Biology. Under the License and Publishing Agreement, authors grant to the general public, effective two months after publication of (i.e.,. the appearance of) the edited manuscript in an online issue of MBoC, the nonexclusive right to copy, distribute, or display the manuscript subject to the terms of the Creative Commons–Noncommercial–Share Alike 3.0 Unported license (http://creativecommons.org/licenses/by-nc-sa/3.0).The small guanosine triphosphate (GTP)-binding proteins of the Rho family are implicated in various cell functions, including establishment and maintenance of cell polarity. Activity of Rho guanosine triphosphatases (GTPases) is not only regulated by guanine nucleotide exchange factors and GTPase-activating proteins but also by guanine nucleotide dissociation inhibitors (GDIs). These proteins have the ability to extract Rho proteins from membranes and keep them in an inactive cytosolic complex. Here, we show that Rdi1, the sole Rho GDI of the yeast Saccharomyces cerevisiae, contributes to pseudohyphal growth and mitotic exit. Rdi1 interacts only with Cdc42, Rho1, and Rho4, and it regulates these Rho GTPases by distinct mechanisms. Binding between Rdi1 and Cdc42 as well as Rho1 is modulated by the Cdc42 effector and p21-activated kinase Cla4. After membrane extraction mediated by Rdi1, Rho4 is degraded by a novel mechanism, which includes the glycogen synthase kinase 3β homologue Ygk3, vacuolar proteases, and the proteasome. Together, these results indicate that Rdi1 uses distinct modes of regulation for different Rho GTPases.Deutsche Forschungsgemeinschaf

    Antiferromagnetic Order Induced by an Applied Magnetic Field in a High-Temperature Superconductor

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    One view of the cuprate high-transition temperature (high-Tc) superconductors is that they are conventional superconductors where the pairing occurs between weakly interacting quasiparticles, which stand in one-to-one correspondence with the electrons in ordinary metals - although the theory has to be pushed to its limit. An alternative view is that the electrons organize into collective textures (e.g. charge and spin stripes) which cannot be mapped onto the electrons in ordinary metals. The phase diagram, a complex function of various parameters (temperature, doping and magnetic field), should then be approached using quantum field theories of objects such as textures and strings, rather than point-like electrons. In an external magnetic field, magnetic flux penetrates type-II superconductors via vortices, each carrying one flux quantum. The vortices form lattices of resistive material embedded in the non-resistive superconductor and can reveal the nature of the ground state - e.g. a conventional metal or an ordered, striped phase - which would have appeared had superconductivity not intervened. Knowledge of this ground state clearly provides the most appropriate starting point for a pairing theory. Here we report that for one high-Tc superconductor, the applied field which imposes the vortex lattice, also induces antiferromagnetic order. Ordinary quasiparticle pictures cannot account for the nearly field-independent antiferromagnetic transition temperature revealed by our measurements

    Selection of an ideal mesh size for the cracking unit of a palm kernel processing plant

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    One of the main problems associated with cracking of palm nut is the mixture of small Tenera and the big Dura variety nuts. In general, low yield of about 40% is obtained from cracking the mixture of Dura-Tenera nuts. In cracking the mixture, most of the Tenera nuts are not cracked when a large sieve size is used. When the sieve size is small, the Dura kernels get broken, thereby affecting the quality of the processed kernel oil. Hence the objective of this work was to develop a model for selecting a suitable sieve size that can be used to crack the nut in order to increase productivity and also improve the quality of the palm kernel oil. Series of experiments carried out confirmed the need for separation of nuts before cracking and also the need to select an ideal sieve size for each type of nut. In conclusion, it was established that separating the two nut varieties before cracking led to a significant (p< 0.01) increase in cracking efficiency of up to about 90% thereby increasing the productivity by 40% and making an economic gain of GH¢ 1.07 (US$0.98, October, 2008) per every 50 kg nut processed

    “We now have a patient and not a criminal” : An exploratory study of judges and lawyers’ views on suicide attempters and the law in Ghana

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    This study explored the views of judges and lawyers of the superior courts of Ghana on the law criminalizing attempted suicide. Qualitative data were collected from 12 experienced legal practitioners of the superior courts (five judges and seven lawyers) using a semi-structured interview schedule. Thematic analysis of the data yielded three main perspectives: In defence of the Law, Advocating a Repeal, and Pro-Health Orientation. Although exploratory, the findings of this study offer cues for stepping up suicide literacy and advocacy programmes toward either a repeal of the law or a reform

    Effects Of Cutting Parameters On Acoustic Emission Signal Response During Drilling Of Laminated Composites Using Factorial Design Method

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    Factorial design has been used to study the effect of cutting parameters on acoustic emission signal response during the drilling of composite laminates. Experimental design is a strategy of planning, conducting, analyzing and interpreting experiments so that sound and valid conclusion can be drawn efficiently, and economically. In this study, effects of cutting speed, feed rate and tool diameter on the acoustic emission signal response are investigated using acoustic emission\'s energy, amplitude, root mean square and frequency responses and 23 factorial design for drilling operation. Cutting tests were performed under dry conditions. Calculated effects, standard errors at 95% confidence level, and models governing the acoustic emission response to the cutting conditions have been generated from the acoustic emission signal responses. The results revealed that, acoustic energy response has significant effects due to the cutting parameters. Hence a model can be established to relate the acoustic emission\'s energy response and the cutting parameters, and as a result monitor and control the area of delamination during the drilling process.Journal of Science & Technology (Ghana) Vol. 27 (2) 2007: pp. 98-10

    Aberrant iPSC-derived human astrocytes in Alzheimer's disease

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    The pathological potential of human astroglia in Alzheimer's disease (AD) was analysed in vitro using induced pluripotent stem cell (iPSC) technology. Here, we report development of a human iPSC-derived astrocyte model created from healthy individuals and patients with either early-onset familial AD (FAD) or the late-onset sporadic form of AD (SAD). Our chemically-defined and highly efficient model provides >95% homogeneous populations of human astrocytes within 30 days of differentiation from cortical neural progenitor cells (NPCs). All astrocytes expressed functional markers including; glial fibrillary acidic protein (GFAP), excitatory amino acid transporter 1 (EAAT1), S100B and glutamine synthetase (GS) comparable to that of adult astrocytes in vivo. However, induced astrocytes derived from both SAD and FAD patients exhibit a pronounced pathological phenotype, with a significantly less complex morphological appearance, overall atrophic profiles, and abnormal localisation of key functional astroglial markers. Furthermore, NPCs derived from identical patients did not show any differences, therefore, validating that remodelled astroglia are not as a result of defective neuronal intermediates. This work not only presents a novel model to study the mechanisms of human astrocytes in vitro, but also provides an ideal platform for further interrogation of early astroglial cell-autonomous events in AD and the possibility of identification of novel therapeutic targets for the treatment of AD

    Insights Into Auditory Cortex Dynamics From Non-invasive Brain Stimulation

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    Non-invasive brain stimulation (NIBS) has been widely used as a research tool to modulate cortical excitability of motor as well as non-motor areas, including auditory or language-related areas. NIBS, especially transcranial magnetic stimulation (TMS) and transcranial direct current stimulation, have also been used in clinical settings, with however variable therapeutic outcome, highlighting the need to better understand the mechanisms underlying NIBS techniques. TMS was initially used to address causality between specific brain areas and related behavior, such as language production, providing non-invasive alternatives to lesion studies. Recent literature however suggests that the relationship is not as straightforward as originally thought, and that TMS can show both linear and non-linear modulation of brain responses, highlighting complex network dynamics. In particular, in the last decade, NIBS studies have enabled further advances in our understanding of auditory processing and its underlying functional organization. For instance, NIBS studies showed that even when only one auditory cortex is stimulated unilaterally, bilateral modulation may result, thereby highlighting the influence of functional connectivity between auditory cortices. Additional neuromodulation techniques such as transcranial alternating current stimulation or transcranial random noise stimulation have been used to target frequency-specific neural oscillations of the auditory cortex, thereby providing further insight into modulation of auditory functions. All these NIBS techniques offer different perspectives into the function and organization of auditory cortex. However, further research should be carried out to assess the mode of action and long-term effects of NIBS to optimize their use in clinical settings

    Police views of suicidal persons and the law criminalizing attempted suicide in Ghana: A qualitative study with policy implications

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    The penal code of Ghana condemns suicide attempt. The present study sought to explore the views of the police on persons who attempt suicide and the law criminalizing the act. Qualitative in-depth interviews were used to explore the views of 18 officers of the Ghana Police Service. Data were analyzed using thematic analysis technique. Findings showed that the police officers profiled suicide attempters as needy, enigmatic, ignorant, and blameworthy. Majority (n = 14) of them disagreed with the law and suggested a repeal, whereas only four of them agreed with the law. Regardless of their positions on criminalization, they showed an inclination to help, rather than arrest, when confronted with such persons in line of their duty. Educating the police on suicidal behavior may help to deepen their understanding and help improve the way they handle suicidal persons. This may also strengthen police suicide prevention gatekeeping obligations
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