924 resultados para L1 norm


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BACKGROUND: The month of diagnosis in childhood type 1 diabetes shows seasonal variation.

OBJECTIVE: We describe the pattern and investigate if year-to-year irregularities are associated with meteorological factors using data from 50 000 children diagnosed under the age of 15 yr in 23 population-based European registries during 1989-2008.

METHODS: Tests for seasonal variation in monthly counts aggregated over the 20 yr period were performed. Time series regression was used to investigate if sunshine hour and average temperature data were predictive of the 240 monthly diagnosis counts after taking account of seasonality and long term trends.

RESULTS: Significant sinusoidal pattern was evident in all but two small centers with peaks in November to February and relative amplitudes ranging from ±11 to ±38% (median ±17%). However, most centers showed significant departures from a sinusoidal pattern. Pooling results over centers, there was significant seasonal variation in each age-group at diagnosis, with least seasonal variation in those under 5 yr. Boys showed greater seasonal variation than girls, particularly those aged 10-14 yr. There were no differences in seasonal pattern between four 5-yr sub-periods. Departures from the sinusoidal trend in monthly diagnoses in the period were significantly associated with deviations from the norm in average temperature (0.8% reduction in diagnoses per 1 °C excess) but not with sunshine hours.

CONCLUSIONS: Seasonality was consistently apparent throughout the period in all age-groups and both sexes, but girls and the under 5 s showed less marked variation. Neither sunshine hour nor average temperature data contributed in any substantial way to explaining departures from the sinusoidal pattern.

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Tiotropium is the first bronchodilator to be studied systematically in cystic fibrosis (CF). We investigated whether any intrinsic or extrinsic factors affected pharmacokinetic (PK) parameters of inhaled tiotropium delivered by Respimat® in adults and children with CF. Tiotropium PK in patients with CF was compared with that of healthy volunteers and patients with chronic obstructive pulmonary disease (COPD). This pooled analysis summarizes the PK parameters of inhaled tiotropium Respimat® across 9 early- and late-phase trials involving 27 healthy volunteers (1 trial), 409 patients with CF (3 trials), and 281 patients with COPD (5 trials). Patients with CF aged 5 to 11, 12 to 17, and ≥18 years had similar tiotropium plasma concentrations (geometric mean C0.083,ss,norm: 2.22pg/mL/μg; not determined for patients aged <5 years). The fraction excreted unchanged in the urine was 3.4-fold lower for patients aged 0.4 to <5 years than for those aged 5 to 11 years (fe0-4,ss: 1.19% vs 4.09%). Tiotropium PK parameters were similar between CF patients and COPD patients.

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We show that if E is an atomic Banach lattice with an ordercontinuous norm, A, B ∈ Lr(E) and MA,B is the operator on Lr(E) defined by MA,B(T) = AT B then ||MA,B||r = ||A||r||B||r but that there is no real α > 0 such that ||MA,B || ≥ α ||A||r||B ||r.

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We describe all two dimensional unital Riesz algebras and study representations of them in Riesz algebras of regular operators. Although our results are not complete, we do demonstrate that very varied behaviour can occur even though all these algebras can be given a Banach lattice algebra norm.

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This paper investigates the gene selection problem for microarray data with small samples and variant correlation. Most existing algorithms usually require expensive computational effort, especially under thousands of gene conditions. The main objective of this paper is to effectively select the most informative genes from microarray data, while making the computational expenses affordable. This is achieved by proposing a novel forward gene selection algorithm (FGSA). To overcome the small samples' problem, the augmented data technique is firstly employed to produce an augmented data set. Taking inspiration from other gene selection methods, the L2-norm penalty is then introduced into the recently proposed fast regression algorithm to achieve the group selection ability. Finally, by defining a proper regression context, the proposed method can be fast implemented in the software, which significantly reduces computational burden. Both computational complexity analysis and simulation results confirm the effectiveness of the proposed algorithm in comparison with other approaches

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This paper considers the value of a normative account of the relationship between agents and institutions for contemporary efforts to explain ever more complex and disorganized forms of social life. The character of social institutions, as they relate to practices, agents and norms, is explored through an engagement with the common claim that family life has been deinstitutionalized. The paper argues that a normative rather than empirical definition of institutions avoids a false distinction between institutions and practices. Drawing on ideas of social freedom and creative action from critical theory, the changes in family life are explained not as an effect of deinstitutionalization, but as a shift from an organized to a disorganized institutional type. This is understood as a response to changes in the wider normative structure, as a norm of individual freedom has undermined the legitimacy of the organized patriarchal nuclear family, with gender ascribed roles and associated duties. Contemporary motherhood is drawn on to illustrate the value of analysing the dynamic interactions between institutions, roles and practices for capturing both the complexity and the patterned quality of social experience.

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Back pain is a common complaint in pregnancy, affecting approximately two-thirds of pregnant women [Pennick and Lidle, 2013]. This can lead to increased disability, affecting daily activities and cause absence from work. Evidence-based recommendations can be made for the use of exercise as an effective conservative treatment for the relief of back pain in pregnancy [Benten et al, 2014]. This poster explores the background to back pain in pregnancy and the advice women should be offered in relation to exercise to help normalise their pregnancy experience and enhance wellbeing.

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It is estimated that the cost of treating women and their infants with smoking related problems is up to £87.5 million each year (ASH, 2013). Whilst these statistics depict a major problem for the National Health Service, they challenge midwives to become change agents within this health promotion area. A desired outcome from The Maternity Strategy for Northern Ireland (DHSSPSNI, 2012) includes giving every baby and family the best start in life. Assisting women to stop smoking before conception, could help to achieve this outcome and provide opportunities for a greater start in life following birth.

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Breastfeeding rates in Northern Ireland are substantially lower in Northern Ireland compared to the rest of the United Kingdom (McAndrew et al, 2012). Midwives carry a responsibility within their health promotion activities to reiterate the benefits of breastfeeding and support women to make empowered decisions with regard to feeding their baby. This poster explores some of the challenges faced by midwives in relation to supporting women to make empowered choices and explores how midwives can help normalise breastfeeding within the clinical practice setting

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Co-Sleeping and bed sharing are considered the social norm for approximately 90% of the world's population, with two-thirds of the world's cultures habitually practicing mother-infant co-sleeping on the same bed. Although international studies show that the practice of co-sleeping is common, it is controversial in the public health community, as many consider it a significant risk for Sudden Infant Death Syndrome (SIDS), accounting for 50% of SIDS deaths in the UK. The report offers an international review of the evidence and provides important debates and critical knowledge for both health professionals, parents and all those organisations working to support the safety of infants in their first perinatal year.

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High gene flow is considered the norm for most marine organisms and is expected to limit their ability to adapt to local environments. Few studies have directly compared the patterns of differentiation at neutral and selected gene loci in marine organisms. We analysed a transcriptome-derived panel of 281 SNPs in Atlantic herring (Clupea harengus), a highly migratory small pelagic fish, for elucidating neutral and selected genetic variation among populations and to identify candidate genes for environmental adaptation. We analysed 607 individuals from 18 spawning locations in the northeast Atlantic, including two temperature clines (5-12 °C) and two salinity clines (5-35‰). By combining genome scan and landscape genetic analyses, four genetically distinct groups of herring were identified: Baltic Sea, Baltic-North Sea transition area, North Sea/British Isles and North Atlantic; notably, samples exhibited divergent clustering patterns for neutral and selected loci. We found statistically strong evidence for divergent selection at 16 outlier loci on a global scale, and significant correlations with temperature and salinity at nine loci. On regional scales, we identified two outlier loci with parallel patterns across temperature clines and five loci associated with temperature in the North Sea/North Atlantic. Likewise, we found seven replicated outliers, of which five were significantly associated with low salinity across both salinity clines. Our results reveal a complex pattern of varying spatial genetic variation among outlier loci, likely reflecting adaptations to local environments. In addition to disclosing the fine scale of local adaptation in a highly vagile species, our data emphasize the need to preserve functionally important biodiversity.

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Context. The magnetic activity of planet-hosting stars is an importantfactor for estimating the atmospheric stability of close-in exoplanetsand the age of their host stars. It has long been speculated thatclose-in exoplanets can influence the stellar activity level. However,testing for tidal or magnetic interaction effects in samples ofplanet-hosting stars is difficult because stellar activity hindersexoplanet detection, so that stellar samples with detected exoplanetsshow a bias toward low activity for small exoplanets.

Aims: Weaim to test whether exoplanets in close orbits influence the stellarrotation and magnetic activity of their host stars.

Methods: Wedeveloped a novel approach to test for systematic activity-enhancementsin planet-hosting stars. We use wide (several 100 AU) binary systems inwhich one of the stellar components is known to have an exoplanet, whilethe second stellar component does not have a detected planet andtherefore acts as a negative control. We use the stellar coronal X-rayemission as an observational proxy for magnetic activity and analyzeobservations performed with Chandra and XMM-Newton.

Results: Wefind that in two systems for which strong tidal interaction can beexpected the planet-hosting primary displays a much higher magneticactivity level than the planet-free secondary. In three systems forwhich weaker tidal interaction can be expected the activity levels ofthe two stellar components agree with each other.

Conclusions:Our observations indicate that the presence of Hot Jupiters may inhibitthe spin-down of host stars with thick outer convective layers. Possiblecauses for this effect include a transfer of angular momentum from theplanetary orbit to the stellar rotation through tidal interaction, ordifferences during the early evolution of the system, where the hoststar may decouple from the protoplanetary disk early because of a gapopened by the forming Hot Jupiter.

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A multiuser dual-hop relaying system over mixed radio frequency/free-space optical (RF/FSO) links is investigated. Specifically, the system consists of m single-antenna sources, a relay node equipped with n≥ m receive antennas and a single photo-aperture transmitter, and one destination equipped with a single photo-detector. RF links are used for the simultaneous data transmission from multiple sources to the relay. The relay operates under the decode-and-forward protocol and utilizes the popular V-BLAST technique by successively decoding each user's transmitted stream. Two common norm-based orderings are adopted, i.e., the streams are decoded in an ascending or a descending order. After V-BLAST, the relay retransmits the decoded information to the destination via a point-to-point FSO link in m consecutive timeslots. Analytical expressions for the end-to-end outage probability and average symbol error probability of each user are derived, while closed-form asymptotic expressions are also presented. Capitalizing on the derived results, some engineering insights are manifested, such as the coding and diversity gain of each user, the impact of the pointing error displacement on the FSO link and the V-BLAST ordering effectiveness at the relay.

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Purpose:
Social norms influence eating behavior, but little is known about their role in portion size-related behavior. This study
explored the role of social eating norms in Denmark (DK) and the Island of Ireland (IOI) in relation to portion size-related
behavior.

Methods:
In a survey DK (n=1063) and IOI (n=1012) respondents rated social eating norms (11 items) and portion size-related behavior
(3 items) on a 7-point scale (1=strongly disagree to 7=strongly agree). The 3 items relate to: 1) anticipating how
much will be eaten at the beginning of a meal, 2) clearing the plate, and 3) clearing the plate even when full. Sociodemographics
and eating attitudes (e.g. cognitive restraint) were measured as background variables

Results:
Two social eating factors were identified: The ‘limit intake’ norm (6 items) and the ‘plate cleaning’ norm (3 items). The
DK participants reported stronger ‘limit intake’ norms and weaker ‘plate cleaning’ norms than IOI. In both countries
females reported stronger ‘limit intake’ norms while males reported stronger ‘plate cleaning’ norms. In DK, age was
positively correlated with both social eating norm factors. The ‘limit intake’ norm had stronger association with anticipating
how much will be eaten at the beginning of a meal, but the ‘plate cleaning’ norm had stronger association with
clearing the plate. Only the ‘plate cleaning’ norm was associated with clearing the plate even when full.

Conclusions:
The social eating norms vary significantly between countries and genders. The ‘limit intake’ and ‘plate cleaning’ norms
play a role in consumers’ reported portion size-related behavior.