14,896 research outputs found

    Personal relatedness and attachment in infants of mothers with borderline personality disorder

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    The principal aim of this study was to assess personal relatedness and attachment patterns in 12-month-old infants of mothers with borderline personality disorder (BPD). We also evaluated maternal intrusive insensitivity toward the infants in semistructured play. We videotaped 10 mother-infant dyads with borderline mothers and 22 dyads where the mothers were free from psychopathology, in three different settings: a modification of Winnicott's Set Situation in which infants faced an initially unresponsive ("still-face") stranger, who subsequently tried to engage the infant in a game of give and take; the Strange Situation of Ainsworth and Wittig; and a situation in which mothers were requested to teach their infants to play with miniature figures and a toy train. In relation to a set of a priori predictions, the results revealed significant group differences as follows: (a) compared with control infants, toward the stranger the infants of mothers with BPD showed lower levels of "availability for positive engagement," lower ratings of "behavior organization and mood state," and a lower proportion of interpersonally directed looks that were positive; (b) in the Strange Situation, a higher proportion (8 out of 10) of infants of borderline mothers were categorized as Disorganized; and (c) in play, mothers with BPD were rated as more "intrusively insensitive" toward their infants. The results are discussed in relation to hypotheses concerning the interpersonal relations of women with BPD, and possible implications for their infants' development

    Energy Efficient and Reliable ARQ Scheme (ER-ACK) for Mission Critical M2M/IoT Services

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    Wireless sensor networks (WSNs) are the main infrastructure for machine to machine (M2M) and Internet of thing (IoT). Since various sophisticated M2M/IoT services have their own quality-of-service (QoS) requirements, reliable data transmission in WSNs is becoming more important. However, WSNs have strict constraints on resources due to the crowded wireless frequency, which results in high collision probability. Therefore a more efficient data delivering scheme that minimizes both the transmission delay and energy consumption is required. This paper proposes energy efficient and reliable data transmission ARQ scheme, called energy efficient and reliable ACK (ER-ACK), to minimize transmission delay and energy consumption at the same time. The proposed scheme has three aspects of advantages compared to the legacy ARQ schemes such as ACK, NACK and implicit-ACK (I-ACK). It consumes smaller energy than ACK, has smaller transmission delay than NACK, and prevents the duplicated retransmission problem of I-ACK. In addition, resource considered reliability (RCR) is suggested to quantify the improvement of the proposed scheme, and mathematical analysis of the transmission delay and energy consumption are also presented. The simulation results show that the ER-ACK scheme achieves high RCR by significantly reducing transmission delay and energy consumption

    Rigidity and volume preserving deformation on degenerate simplices

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    Given a degenerate (n+1)(n+1)-simplex in a dd-dimensional space MdM^d (Euclidean, spherical or hyperbolic space, and d≄nd\geq n), for each kk, 1≀k≀n1\leq k\leq n, Radon's theorem induces a partition of the set of kk-faces into two subsets. We prove that if the vertices of the simplex vary smoothly in MdM^d for d=nd=n, and the volumes of kk-faces in one subset are constrained only to decrease while in the other subset only to increase, then any sufficiently small motion must preserve the volumes of all kk-faces; and this property still holds in MdM^d for d≄n+1d\geq n+1 if an invariant ck−1(αk−1)c_{k-1}(\alpha^{k-1}) of the degenerate simplex has the desired sign. This answers a question posed by the author, and the proof relies on an invariant ck(ω)c_k(\omega) we discovered for any kk-stress ω\omega on a cell complex in MdM^d. We introduce a characteristic polynomial of the degenerate simplex by defining f(x)=∑i=0n+1(−1)ici(αi)xn+1−if(x)=\sum_{i=0}^{n+1}(-1)^{i}c_i(\alpha^i)x^{n+1-i}, and prove that the roots of f(x)f(x) are real for the Euclidean case. Some evidence suggests the same conjecture for the hyperbolic case.Comment: 27 pages, 2 figures. To appear in Discrete & Computational Geometr

    Dynamic selective switching in antiferromagnetically-coupled bilayers close to the spin reorientation transition

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    We have designed a bilayer synthetic antiferromagnet where the order of layer reversal can be selected by varying the sweep rate of the applied magnetic field. The system is formed by two ultra-thin ferromagnetic layers with different proximities to the spin reorientation transition, coupled antiferromagnetically using Ruderman-Kittel-Kasuya-Yosida interactions. The different dynamic magnetic reversal behavior of both layers produces a crossover in their switching fields for field rates in the kOe/s range. This effect is due to the different effective anisotropy of both layers, added to an appropriate asymmetric antiferromagnetic coupling between them. Field-rate controlled selective switching of perpendicular magnetic anisotropy layers as shown here can be exploited in sensing and memory applications.Copyright (2014) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters (volume 105: 092408) and may be found at http://scitation.aip.org/content/aip/journal/apl/105/9/10.1063/1.4895032

    Ultraviolet radiation and cyanobacteria.

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    Cyanobacteria are the dominant photosynthetic prokaryotes from an ecological, economical, or evolutionary perspective, and depend on solar energy to conduct their normal life processes. However, the marked increase in solar ultraviolet radiation (UVR) caused by the continuous depletion of the stratospheric ozone shield has fueled serious concerns about the ecological consequences for all living organisms, including cyanobacteria. UV-B radiation can damage cellular DNA and several physiological and biochemical processes in cyanobacterial cells, either directly, through its interaction with certain biomolecules that absorb in the UV range, or indirectly, with the oxidative stress exerted by reactive oxygen species. However, cyanobacteria have a long history of survival on Earth, and they predate the existence of the present ozone shield. To withstand the detrimental effects of solar UVR, these prokaryotes have evolved several lines of defense and various tolerance mechanisms, including avoidance, antioxidant production, DNA repair, protein resynthesis, programmed cell death, and the synthesis of UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin. This study critically reviews the current information on the effects of UVR on several physiological and biochemical processes of cyanobacteria and the various tolerance mechanisms they have developed. Genomic insights into the biosynthesis of MAAs and scytonemin and recent advances in our understanding of the roles of exopolysaccharides and heat shock proteins in photoprotection are also discussed

    Symbolic play in congenitally blind children

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    There is controversy over the existence and nature of blind children's limitations in symbolic play. In this study we tested 13 5- to 9-year-old congenitally blind children for the ability to symbolize when an adult provided scaffolding for their play. The blind children were selected on the basis that they did not have the syndrome of autism, and they comprised two groups matched for age (MA) and verbal ability on the Wechsler Intelligence Scale for Children who contrasted in their ability to engage in social relations. We also tested a group of sighted children who were MA matched with the more socially able blind children. On the basis of an hypothesis about the social-developmental sources of symbolic play deficits in congenitally blind children, we predicted differences between the socially able and socially impaired groups of blind children in the following respects: the attribution of symbolic meanings to play materials, the ascription of individual roles to play figures, and the anchorage of play in the scenario as presented by the adult. The results accorded with these predictions. Whereas the more socially able blind children showed symbolic play that was very similar to that of sighted children, the MA- and IQ-matched socially impaired blind children were limited in the three aspects of their play. On the other hand, even the socially impaired children showed instances of symbolizing. The findings suggest a way to reconcile conflicting reports of symbolic play deficits in young blind children, and may be relevant for explaining the association between autism and congenital blindness

    The role of brand loyalty and social media in e-commerce interfaces: survey results and implications for user interfaces

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    This paper explores the role of brand loyalty and social media in e-commerce interfaces. A survey consisting of 118 respondents was contacted to address the questions relating to online shopping and brand loyalty. Link between the frequency of access and time spent on an e-commerce user interface, and brand loyalty, gender and age profile differences, and the role of social media to branding and on-line shopping was analyzed. It was found that online loyalty differs from offline loyalty and loyalty also differed across genders, showing men were more loyal than women when shopping online. Information shared about products on social media by friends and family played an important role in purchase decision making. Website interface and ease of navigation were also key aspects for online shopping. The research concluded with recommendations to create multimodal websites which are more interactive and targeted so customer experience is enhanced and loyalty is achieved through the use of interactivity and social media

    A robust soliton ratchet using combined antiferromagnetic and ferromagnetic interlayer couplings

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    A sharp magnetic soliton can be created and propagated in a vertical ratchet structure based on magnetic layers with out-of-plane anisotropy using a combination of antiferromagnetic and ferromagnetic interlayer couplings. This allows the use of identical magnetic layers in the stack, which simplifies the implementation of the ratchet compared to schemes which use alternating layer thicknesses. The ratchet behavior is analyzed using an Ising-macrospin approximation and conditions are derived for the propagation of a soliton, which is demonstrated experimentally. Values extracted from the experimental data for the coercivities and interlayer couplings show significant variation, which demonstrates the robustness of the soliton propagation.This research was funded by the European Community under the Seventh Framework Program ERC Contract No. 247368: 3SPIN. R.L. acknowledges support from the Netherlands Organization for Scientific Research (VENI 68047428). A.F.-P. acknowledges an EPSRC Early Career fellowship and support from the Winton Programme for the Physics of Sustainability.This is the author accepted manuscript. The final version is available from AIP via http://dx.doi.org/10.1063/1.491401

    Globular Cluster Distance Determinations

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    The present status of the distance scale to Galactic globular clusters is reviewed. Six distance determination techniques which are deemed to be most reliable are discussed in depth. These different techniques are used to calibrate the absolute magnitude of the RR Lyrae stars. The various calibrations fall into three groups. Main sequence fitting using Hipparcos parallaxes, theoretical HB models and the RR Lyrae in the LMC all favor a bright calibration, implying a `long' globular cluster distance scale. White dwarf fitting and the astrometric distances yield a somewhat fainter RR Lyrae calibration, while the statistical parallax solution yields faint RR Lyrae stars implying a `short' distance scale to globular clusters. Various secondary distance indicators discussed all favor the long distance scale. The `long' and `short' distance scales differ by (0.31+/-0.16) mag. Averaging together all of the different distance determinations yields Mv(RR) = (0.23+/-0.04)([Fe/H] + 1.6) + (0.56+/-0.12) mag.Comment: Invited review article to appear in: `Post-Hipparcos Cosmic Candles', A. Heck & F. Caputo (Eds), Kluwer Academic Publ., Dordrecht, in pres
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