4,985 research outputs found
Communication Enhancement Through Quantum Coherent Control of Channels in an Indefinite Causal-order Scenario
In quantum Shannon theory, transmission of information is enhanced by quantum
features. Up to very recently, the trajectories of transmission remained fully
classical. Recently, a new paradigm was proposed by playing quantum tricks on
two completely depolarizing quantum channels i.e. using coherent control in
space or time of the two quantum channels. We extend here this control to the
transmission of information through a network of an arbitrary number of
channels with arbitrary individual capacity i.e. information preservation
characteristics in the case of indefinite causal order. We propose a formalism
to assess information transmission in the most general case of channels in
an indefinite causal order scenario yielding the output of such transmission.
Then we explicitly derive the quantum switch output and the associated Holevo
limit of the information transmission for , as a function of all
involved parameters. We find in the case that the transmission of
information for three channels is twice of transmission of the two channel case
when a full superposition of all possible causal orders is used
Error rate analysis of M-PSK with magnitude modulation envelope control
Magnitude modulation (MM) envelope control is an efficient way of reducing the peak-to-average power ratio (PAPR) of single-carrier (SC) signals and improves an SC system's overall power efficiency. However, MM techniques reduce the PAPR at the cost of introducing distortion, highlighting a need to characterise the symbol error rate (SER) performance loss due to MM. This reported work focuses on the M-PSK case. An exact probability density function (PDF) based on the generalised extreme value distribution is proposed to model the statistical distribution of MM factors generated by MM techniques applied to SC constant amplitude constellations. By considering MM distortion as a form of fading, it is shown that this PDF may be used to derive an accurate union bound of the SER of M-PSK transmission on the additive white Gaussian channel channel when using MM envelope control
Confinement-induced vitrification in polyethylene terephthalate
9 págs.; 5 figs.; 1 app; PACS number s : 61.82.Pv, 61.82.Rx, 64.70.Pf, 05.20. y; Erratum Phys. Rev. B 79, 019903 (2009)Dynamic mechanical thermal analysis performed on cold-drawn polyethylene terephthalate (PET), cold crystallized (annealed) in the temperature interval 100-140°C, reveals the presence of marginally glassy domains above the annealing temperature Ta. This suggests that the thermodynamic force driving crystallization causes the structural arrest of some noncrystalline domains. The latter thus need a temperature higher than Ta to completely defreeze. Differential scanning calorimetry supports this point of view. Analogous investigations on unoriented PET, cold crystallized in the same conditions, do not show the same peculiarities; thus, chain orientation is relevant to vitrification. This phenomenology is first cast in the language of thermodynamics by introducing an excess chemical potential δμ describing the presence of structural constraints in the amorphous domains and the effect of chain orientation. For a first test of this picture, the orientation contribution to δμ is calculated by means of the Gaussian chain model (this implicitly assumes that δμ is related to the density fluctuations). The resulting expression is then used to discuss the structural differences between cold-drawn and unoriented PET samples reported in the literature. © 2007 The American Physical Society.Peer Reviewe
Benefits from using an ankle-foot orthosis in children with myelomeningocele
Myelomeningocele (MMC) or spina bifida is a defect of the neural tube in which the spinal cord, its envelopes (meninges), and vertebral arches develop abnormally in the beginning of gestation, and owing to this failure of closure there appear a series of congenital defects and associated comorbidies, impairing in several aspects the functioning of the life of children with MMC. The congenital clubfoot has been found the most common orthopaedic anomaly in patientswith MMC. The ankle-foot orthosis (AFO) is an orthopaedic device commonly used by these children to minimize the sequelae caused by this anomaly. Objective: Identify the functional benefits brought about by the use of the AFO to children with MMC, as reported by their guardians. Method: Descriptive, transversal study. Convenience sample consisting of 25 guardians of children with MMC who were using/had used an AFO. Results: Eighty percent of the guardians have reported at least one benefit brought about by the use of theAFO, among them: improvement in foot position (68%), foot growth (40%), improvement in foot balance (32%), and balance sitting position (15%). Conclusion: The use of the AFO by children with MMC can provide several benefits reported by their guardians.
Analysis of the dyscalculia with the implementation of a design workshop in CATIA in a primary school in Puebla
In a rural context primary school where a pilot program of full-time schools was promoted and taking into account the component of the new curricular autonomy model 2017. A design and automation workshop was implemented using CATIA software, with the aim of demonstrating that primary students can overcome deficiencies in mathematical skills such as dyscalculia. The workshop was conducted with ten students between six and twelve years' old who, due to their rural context, have little contact with technology. For the realization of this workshop, a survey was carried out for the parents and for the children where the full acceptance of the workshop was manifested. In the same way, the participation of the Technological University of Puebla (UTP) was carried out through mechatronic engineering, which was in charge of teaching the workshop, through the management according to the new educational model. The CATIA software visibly favored students' mathematical skills when designing a march, in addition to reducing school absenteeism and generating a product (wooden tractor) that has more significant benefits than the famous Japanese toy. The evaluation of the project was registered in rubrics in a span of three phases. The end of the whole process we concluded that, due to its low cost, it is possible to implement this workshop in all federal and state primaries regardless of their context and also that any child can operate the calculation using CATIA. With this last observation, we demonstrate that dyscalculia is a myth
Endocannabinoid System and Psychiatry: In Search of a Neurobiological Basis for Detrimental and Potential Therapeutic Effects
Public concern on mental health has noticeably increased given the high prevalence of neuropsychiatric disorders. Cognition and emotionality are the most affected functions in neuropsychiatric disorders, i.e., anxiety disorders, depression, and schizophrenia. In this review, most relevant literature on the role of the endocannabinoid (eCB) system in neuropsychiatric disorders will be presented. Evidence from clinical and animal studies is provided for the participation of CB1 and CB2 receptors (CB1R and CB2R) in the above mentioned neuropsychiatric disorders. CBRs are crucial in some of the emotional and cognitive impairments reported, although more research is required to understand the specific role of the eCB system in neuropsychiatric disorders. Cannabidiol (CBD), the main non-psychotropic component of the Cannabis sativa plant, has shown therapeutic potential in several neuropsychiatric disorders. Although further studies are needed, recent studies indicate that CBD therapeutic effects may partially depend on facilitation of eCB-mediated neurotransmission. Last but not least, this review includes recent findings on the role of the eCB system in eating disorders. A deregulation of the eCB system has been proposed to be in the bases of several neuropsychiatric disorders, including eating disorders. Cannabis consumption has been related to the appearance of psychotic symptoms and schizophrenia. In contrast, the pharmacological manipulation of this eCB system has been proposed as a potential strategy for the treatment of anxiety disorders, depression, and anorexia nervosa. In conclusion, the eCB system plays a critical role in psychiatry; however, detrimental consequences of manipulating this endogenous system cannot be underestimated over the potential and promising perspectives of its therapeutic manipulation
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