572 research outputs found

    Decreasing nighttime fears in children: a thesis ...

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    The purpose of the study was to find out if children ages 4- 5 who were experiencing nighttime fears could be taught coping behaviors to decrease their fears. Five children and their parents participated in the study. A treatment package consisting of teaching the children brave self- statements, relaxation exercises, and the introduction of a token economy was used. Results indicate a reduction in fear behavior at post treatment, and further decreases in fear related measures at follow- up

    On Fixed Beamforming in Sectored mmWave Ultra Dense Networks at 73GHz

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    We investigate the use of fixed analogue transmit beamforming for downlink communication in millimetre-wave (mmWave) band ultra-dense networks (UDNs) at 73GHz. Our simulation study is based on 3D radiation patterns using a real design of large planar antenna arrays with different horizontal beamwidths and full characterisation of interference. The effects of network densification are captured through different ratios of the number of access points (APs) to the number of users. We quantify the system\u27s performance by evaluating outage and achievable rate. The results show that users with rates around the mean benefit more from the densification than from narrowing the beamwidth, but for users with low rates, narrow beams also provide a significant increase in throughput

    Heavier alkaline‐earth catalyzed dehydrocoupling of silanes and alcohols for the synthesis of metallo‐polysilylethers

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    The dehydrocoupling of silanes and alcohols mediated by heavier alkaline-earth catalysts, [Ae{N(SiMe 3) 2} 2⋅(THF) 2] (I–III) and [Ae{CH(SiMe 3) 2} 2⋅(THF) 2], (IV–VI) (Ae=Ca, Sr, Ba) is described. Primary, secondary, and tertiary alcohols were coupled to phenylsilane or diphenylsilane, whereas tertiary silanes are less tolerant towards bulky substrates. Some control over reaction selectivity towards mono-, di-, or tri-substituted silylether products was achieved through alteration of reaction stoichiometry, conditions, and catalyst. The ferrocenyl silylether, FeCp(C 5H 4SiPh(OBn) 2) (2), was prepared and fully characterized from the ferrocenylsilane, FeCp(C 5H 4SiPhH 2) (1), and benzyl alcohol using barium catalysis. Stoichiometric experiments suggested a reaction manifold involving the formation of Ae–alkoxide and hydride species, and a series of dimeric Ae–alkoxides [(Ph 3CO)Ae(μ 2-OCPh 3)Ae(THF)] (3 a–c, Ae=Ca, Sr, Ba) were isolated and fully characterized. Mechanistic experiments suggested a complex reaction mechanism involving dimeric or polynuclear active species, whose kinetics are highly dependent on variables such as the identity and concentration of the precatalyst, silane, and alcohol. Turnover frequencies increase on descending Group 2 of the periodic table, with the barium precatalyst III displaying an apparent first-order dependence in both silane and alcohol, and an optimum catalyst loading of 3 mol % Ba, above which activity decreases. With precatalyst III in THF, ferrocene-containing poly- and oligosilylethers with ferrocene pendent to- (P1–P4) or as a constituent (P5, P6) of the main polymer chain were prepared from 1 or Fe(C 5H 4SiPhH 2) 2 (4) with diols 1,4-(HOCH 2) 2-(C 6H 4) and 1,4-(CH(CH 3)OH) 2-(C 6H 4), respectively. The resultant materials were characterized by NMR spectroscopy, gel permeation chromatography (GPC) and DOSY NMR spectroscopy, with estimated molecular weights in excess of 20,000 Da for P1 and P4. The iron centers display reversible redox behavior and thermal analysis showed P1 and P5 to be promising precursors to magnetic ceramic materials. </p

    Predicting User-Perceived Quality Ratings from Streaming Media Data

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    Abstract—Media stream quality is highly dependent on under-lying network conditions, but identifying scalable, unambiguous metrics to discern the user-perceived quality of a media stream in the face of network congestion is a challenging problem. User-perceived quality can be approximated through the use of carefully chosen application layer metrics, precluding the need to poll users directly. We discuss the use of data mining prediction techniques to analyze application layer metrics to determine user-perceived quality ratings on media streams. We show that several such prediction techniques are able to assign correct (within a small tolerance) quality ratings to streams with a high degree of accuracy. The time it takes to train and tune the predictors and perform the actual prediction are short enough to make such a strategy feasible to be executed in real time and on real computer networks. I

    Essential Questions on Suicide Bereavement and Postvention

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    During the past decades public and research interest in postvention, i.e., support for families and communities after a suicide, has increased. However, the postvention field is still facing a number of important challenges and questions. This article aims to discuss a series of essential issues on suicide bereavement and postvention, regarding the current state of the art and future developments. Who is a suicide survivor and how many suicide survivors are there? Is suicide bereavement different from other types of bereavement? What are the needs of suicide survivors and what is postvention from a clinical perspective and from a public health perspective? Can postvention be prevention? With this last question, the article concludes with a series of recommendations in order to strengthen the potential of postvention as prevention

    The molecular defect of albumin Tagliacozzo: 313 Lys → Asn

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    AbstractAlbumin Tagliacozzo is a fast-moving genetic variant of human serum albumin found in 19 unrelated families. The protein was isolated from the serum of a heterozygous healthy subject. Analysis of CNBr fragments by isoelectric focusing allowed us to localize the mutation to CNBr fragment IV (residues 299–329). This fragment was isolated on a preparative scale and subjected to tryptic digestion. Sequential analysis of the abnormal tryptic peptide, purified by RP-HPLC, revealed the variant was caused by 313 Lys → Asn substitution, probably due to a point mutation in the structural gene. The lack of a lysine residue accounts for the electrophoretic behavior of albumin Tagliacozzo
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