MM Algorithms for Geometric and Signomial Programming

This paper derives new algorithms for signomial programming, a generalization of geometric programming. The algorithms are based on a generic principle for optimization called the MM algorithm. In this setting, one can apply the geometric-arithmetic mean inequality and a supporting hyperplane inequality to create a surrogate function with parameters separated. Thus, unconstrained signomial programming reduces to a sequence of one-dimensional minimization problems. Simple examples demonstrate that the MM algorithm derived can converge to a boundary point or to one point of a continuum of minimum points. Conditions under which the minimum point is unique or occurs in the interior of parameter space are proved for geometric programming. Convergence to an interior point occurs at a linear rate. Finally, the MM framework easily accommodates equality and inequality constraints of signomial type. For the most important special case, constrained quadratic programming, the MM algorithm involves very simple updates.Comment: 16 pages, 1 figur

Interictal epileptiform discharges have an independent association with cognitive impairment in children with lesional epilepsy

OBJECTIVES: The relative contribution of interictal epileptiform discharges (IEDs) to cognitive dysfunction in comparison with the underlying brain pathology is not yet understood in children with lesional focal epilepsy. METHODS: The current study investigated the association of IEDs with intellectual functioning in 103 children with medication-resistant focal epilepsy. Hierarchical multiple regression analyses were used to determine the independent contribution of IED features on intellectual functioning, after controlling for effects of lesional pathology, epilepsy duration, and medication. Exploratory analyses were conducted for language and memory scores as well as academic skills available in a subset of participants. RESULTS: The results reveal that IEDs have a negative association with IQ with independent, additive effects documented for frequent and bilaterally distributed IEDs as well as discharge enhancement in sleep. Left-lateralized IEDs had a prominent effect on verbal intelligence, in excess of the influence of left-sided brain pathology. These effects extended to other cognitive functions, most prominently for sleep-enhanced IEDs to be associated with deficits in expressive and receptive language, reading, spelling and numerical skills. SIGNIFICANCE: Overall, IED effects on cognition were of a magnitude similar to lesional influences or drug effects (topiramate use). This study demonstrates an association between IEDs and cognitive dysfunction, independent of the underlying focal brain pathology

Pneumococcal capsular polysaccharide immunity in the elderly.

Immunity against pneumococcal infections is impaired in older people, and current vaccines are poorly protective against pneumococcal disease in this population. Naturally-acquired immunity against pneumococcal capsular polysaccharides develops during childhood and is robust in young adults, but deteriorates with advanced age. In particular, antibody levels and function are reduced in older people. Pneumococcal vaccines are recommended for people over 65 years of age. However, the benefits of polysaccharide and protein-conjugated vaccines in this population are small, due to both serotype replacement and incomplete protection against vaccine-serotype pneumococcal disease. In this review we overview the immune mechanisms by which naturally-acquired and vaccine-induced pneumococcal capsular polysaccharide immunity declines with age, including altered colonization dynamics, reduced opsonic activity of antibodies (particularly IgM) and impaired mucosal immunity

Quality of care assessment for people with multimorbidity.

Multimorbidity, the simultaneous presence of multiple health conditions in an individual, is an increasingly common phenomenon globally. The systematic assessment of the quality of care delivered to people with multimorbidity will be key to informing the organization of services for meeting their complex needs. Yet, current assessments tend to focus on single conditions and do not capture the complex processes that are required for providing care for people with multimorbidity. We conducted a scoping review on quality of care and multimorbidity in selected databases in June 2018 and identified 87 documents as eligible for review, predominantly original research and reviews from North America, Europe and Australasia and mostly frequently related to primary care settings. We synthesized data qualitatively in terms of perceived challenges, evidence and proposed metrics. Findings reveal that the association between quality of care and multimorbidity is complex and depends on the conditions involved (quality appears to be higher for those with concordant conditions, and lower in the presence of discordant conditions) and the approach used for measuring quality (quality appears to be higher in people with multimorbidity when measured using condition/drug-specific process or intermediate outcome indicators, and worse when using patient-centred reports of experiences of care). People with discordant multimorbidity may be disadvantaged by current approaches to quality assessment, particularly when they are linked to financial incentives. A better understanding of models of care that best meet the needs of this group is needed for developing appropriate quality assessment frameworks. Capturing patient preferences and values and incorporate patients' voices in the form of patient-reported experiences and outcomes of care will be critical towards the achievement of high-performing health systems that are responsive to the needs of people with multimorbidity

Observation of second-harmonic generation induced by pure spin currents

Extensive efforts are currently being devoted to developing a new electronic technology, called spintronics, where the spin of electrons is explored to carry information. [1,2] Several techniques have been developed to generate pure spin currents in many materials and structures. [3-10] However, there is still no method available that can be used to directly detect pure spin currents, which carry no net charge current and no net magnetization. Currently, studies of pure spin currents rely on measuring the induced spin accumulation with optical techniques [5, 11-13] or spin-valve configurations. [14-17] However, the spin accumulation does not directly reflect the spatial distribution or temporal dynamics of the pure spin current, and therefore cannot monitor the pure spin current in a real-time and real-space fashion. This imposes severe constraints on research in this field. Here we demonstrate a second-order nonlinear optical effect of the pure spin current. We show that such a nonlinear optical effect, which has never been explored before, can be used for the non-invasive, non-destructive, and real-time imaging of pure spin currents. Since this detection scheme does not rely on optical resonances, it can be generally applied in a wide range of materials with different electronic bandstructures. Furthermore, the control of nonlinear optical properties of materials with pure spin currents may have potential applications in photonics integrated with spintronics.Comment: 19 pages, 3 figures, supplementary discussion adde

Molecular pathogenesis of proliferative verrucous leukoplakia: a systematic review

Proliferative verrucous leukoplakia (PVL) is a potentially premalignant lesion that undergoes malignant transformation in over 40% of cases. Its clinical homogeneity suggests that a single or a small number of molecular pathogenic pathways may exist. Using the Cochrane protocol for systematic reviews, we have looked at the reported evidence of the molecular aetiology and pathogenesis of PVL and compared it with that of conventional oral epithelial dysplasia (OED). Of the 43 papers studied, 19 met the inclusion criteria including 13 proteins assayed in 344 tissues, and genes investigated were TP53, p14ARF, and p16INK4A. In all studies the research objectives were defined and outcomes were clearly stated. This review has shown that the transformation of PVL does not follow the same pathway as that of OED. There was weak evidence to suggest possible correlations between DNA aneuploidy, loss of heterozygosity at locus 9p21, and specific expression of Mcm (mini chromosome maintenance) protein, to transformation of PVL. To show important or distinct pathways of this condition, further studies are needed to access the somatic genomic alterations that are found in malignancies

Theoretical and Phenomenological Constraints on Form Factors for Radiative and Semi-Leptonic B-Meson Decays

We study transition form factors for radiative and rare semi-leptonic B-meson decays into light pseudoscalar or vector mesons, combining theoretical constraints and phenomenological information from Lattice QCD, light-cone sum rules, and dispersive bounds. We pay particular attention to form factor parameterisations which are based on the so-called series expansion, and study the related systematic uncertainties on a quantitative level. In this context, we also provide the NLO corrections to the correlation function between two flavour-changing tensor currents, which enters the unitarity constraints for the coefficients in the series expansion.Comment: 52 pages; v2: normalization error in (29ff.) corrected, conclusion about relevance of unitarity bounds modified; form factor fits unaffected; references added; v3: discussion on truncation of series expansion added, matches version to be published in JHEP; v4: corrected typos in Tables 5 and

Second law, entropy production, and reversibility in thermodynamics of information

We present a pedagogical review of the fundamental concepts in thermodynamics of information, by focusing on the second law of thermodynamics and the entropy production. Especially, we discuss the relationship among thermodynamic reversibility, logical reversibility, and heat emission in the context of the Landauer principle and clarify that these three concepts are fundamentally distinct to each other. We also discuss thermodynamics of measurement and feedback control by Maxwell's demon. We clarify that the demon and the second law are indeed consistent in the measurement and the feedback processes individually, by including the mutual information to the entropy production.Comment: 43 pages, 10 figures. As a chapter of: G. Snider et al. (eds.), "Energy Limits in Computation: A Review of Landauer's Principle, Theory and Experiments

Analytic Continuation of Liouville Theory

Correlation functions in Liouville theory are meromorphic functions of the Liouville momenta, as is shown explicitly by the DOZZ formula for the three-point function on the sphere. In a certain physical region, where a real classical solution exists, the semiclassical limit of the DOZZ formula is known to agree with what one would expect from the action of the classical solution. In this paper, we ask what happens outside of this physical region. Perhaps surprisingly we find that, while in some range of the Liouville momenta the semiclassical limit is associated to complex saddle points, in general Liouville's equations do not have enough complex-valued solutions to account for the semiclassical behavior. For a full picture, we either must include "solutions" of Liouville's equations in which the Liouville field is multivalued (as well as being complex-valued), or else we can reformulate Liouville theory as a Chern-Simons theory in three dimensions, in which the requisite solutions exist in a more conventional sense. We also study the case of "timelike" Liouville theory, where we show that a proposal of Al. B. Zamolodchikov for the exact three-point function on the sphere can be computed by the original Liouville path integral evaluated on a new integration cycle.Comment: 86 pages plus appendices, 9 figures, minor typos fixed, references added, more discussion of the literature adde