AFM of metallic nano-particles and nano-structures in heavily irradiated NaCl

AFM investigations are reported for heavily, electron irradiated NaCl crystals in ultra high vacuum (UHV) in the non-contact mode with an UHV AFM/STM Omicron system. To avoid chemical reactions between the radiolytic Na and oxygen and water, the irradiated samples were cleaved and prepared for the experiments in UHV. At the surface of freshly cleaved samples, we have observed sodium nano-precipitates with shapes, which depend on the irradiation dose and the volume fraction of the radiolytic Na. It appears that the nano-structures consist of (i) isolated nano-particles, (ii) more or less random aggregates of these particles, (iii) fractally shaped networks and (iv) ‘‘fabrics’’ consisting of bundles of Quasi-1D arrays forming polymeric networks of nano-particles. Almost independent of the concentration of the metallic Na in the samples the size of the individual nano-particles is in the range 1–3 nm. Our new AFM results are fully in line with our CESR and previous Raman scattering results.

Path Tracking Controller of Quadruped Robot for Obstacle Avoidance Using Potential Functions Method

This paper proposes a tracking controller for obstacle avoidance of a quadruped robot using potential functions method. The followings are done for this task. At first, a ceiling-mounted camera system is installed for image processing. The goal point and obstacles are separated and recognized by a color recognition method. Second, a path planning algorithm using potential functions method is proposed to generate the path to avoid obstacles and to plan a path for the quadruped robot to reach from start point to goal point. Third, a quadruped robot is chosen as the mobile platform for this study and the kinematic model for the robot is presented. Fourth, a tracking controller is designed for the quadruped robot to track the trajectory based on the backstepping method using Lyapunov function. Finally, the simulation results are presented to show the effectiveness of the proposed trajectory planning algorithm and the tracking controller. [Keywords— Path tracking; back stepping; obstacles avoidance; potential functions; quadruped robot]

Effect of fiber orientation on shape and stability of air-water interface on submerged superhydrophobic electrospun thin coatings

To better understand the role of fiber orientation on the stability of superhydrophobicelectrospun coatings under hydrostaticpressures, an integro-differential equation is developed from the balance of forces across the air–water interface between the fibers. This equation is solved numerically for a series of superhydrophobicelectrospun coatings comprised of random and orthogonal fiber orientations to obtain the exact 3D shape of the air–water interface as a function of hydrostaticpressure. More important, this information is used to predict the pressure at which the coatings start to transition from the Cassie state to the Wenzel state, i.e., the so-called critical transition pressure. Our results indicate that coatings composed of orthogonal fibers can withstand higher elevated hydrostaticpressures than those made up of randomly orientated fibers. Our results also prove that thin superhydrophobic coatings can better resist the elevated pressures. The modeling methodology presented here can be used to design nanofibrous superhydrophobic coatings for underwater applications

Necessary Condition Hypotheses in Operations Management

Purpose – To show that necessary condition hypotheses are important in operations management, and to present a consistent methodology for building and testing them. Necessary condition hypotheses (“X is necessary for Y”) express conditions that must be present in order to have a desired outcome (e.g. “success”), and to prevent guaranteed failure. These hypotheses differ fundamentally from the common co-variational hypotheses (“more X results in more Y”) and require another methodology for building and testing them. Design/methodology/approach – Reviewing operations management literature for versions of necessary condition hypotheses. Combining previous theoretical and methodological work into a comprehensive and consistent methodology for building and testing such hypotheses. Findings – Necessary condition statements are common in operations management, but current formulations are not precise, and methods used for building and testing them are not always adequate. Outline of the methodology of Necessary Condition Analysis (NCA) consisting of two stepwise methodological approaches, one for building and one for testing necessary conditions. Originality/value – Because necessary condition statements are common in operations management, using methodologies that can build and test such hypotheses contributes to the advancement of operations management research and theory

Continuation rates of alpha-blockers mono-therapy in adult men, prescribed by urologists or general practitioners:A pharmacy-based study

PURPOSE: α-Blockers are commonly used for the treatment of male lower urinary tract symptoms (LUTS). The Dutch GP guideline on male LUTS contains an advice to discontinue treatment after 3-6 months of successful treatment. The guideline for urologists does not support this advice. It is unclear if these differences lead to other patterns of (dis)continuation of α-blockers. We aim to study continuation rates of α-blockers, prescribed by a urologist or a general practitioner (GP), and to predict discontinuation after 1 year. METHODS: We conducted a retrospective inception cohort study on prescription patterns of α-blockers among Dutch men between 2006 and 2014, using the IADB.nl pharmacy prescription database from the University of Groningen. We selected men aged 30 years or older with a first α-blocker prescription between 2006 and 2013, and analysed continuation of prescriptions. RESULTS: The database included 12,191 individual patients with at least one α-blocker prescriptions from a urologist (44.5%) or a GP (55.5%). The median treatment period for patients who started in the GPs office was 210 days, compared to 150 days for patients with a prescription from a urologist. Of all patients, 60.3% (GP prescriptions) and 66.1% (urologists' prescriptions) had discontinued treatment (Chi-square p < 0.001). Discontinuation rates were age dependent with higher rates in the youngest age groups. CONCLUSION: In this study, the discontinuation rate 1 year after the initiation of treatment was high. Although Dutch GP's and urologist's guidelines differ with respect to a discontinuation advice, we could not find clinically relevant difference in (temporary) discontinuation rates

The State of the Art in Tag Ontologies: A Semantic Model for Tagging and Folksonomies

There is a growing interest on how we represent and share tagging data for the purpose of collaborative tagging systems. Conventional tags, however, are not naturally suited for collaborative processes. Being free-text keywords, they are exposed to linguistic variations like case (upper vs lower), grammatical number (singular vs. plural) as well as human typing errors. Additionally, tags depend on the personal views of the world by individual users, and are not normalized for synonymy, morphology or any other mapping. The bottom line of the problem is that tags have no semantics whatsoever. Moreover, even if a user gives some semantics to a tag while using or viewing it, this meaning is not automatically shared with computers since it’s not defined in a machine-readable way. With tagging systems increasing in popularity each day, the evolution of this technology is hindered by this problem. In this paper we discuss approaches to represent tagging activities at a semantic level. We present criteria for the comparison of existing tag ontologies and discuss their strengths and weaknesses in relation to these criteria

Determinants of excessive weight gain after the initiation of insulin therapy in type 2 diabetes mellitus:Retrospective inception cohort study (ZODIAC 60)

AIMS: To explore determinants of excessive weight gain after initiation of insulin therapy in type 2 diabetes mellitus (T2DM), in particular variables identified in the pre-insulin phase.METHODS: We performed a retrospective observational intervention cohort study, by means of a new user design/ inception cohort concerning n = 5086 patients. We studied determinants of excessive weight gain (5 kg or more) in the first year after initiation of insulin therapy, using both visualization and logistic regression analysis with subsequent receiver operation characteristic (ROC) analyses. Potential determinants pre-, at- and post-insulin initiation were included.RESULTS: One out of 10 patients (10.0%) gained 5 kg weight or more. The earliest determinants of excessive weight gain were weight change (inversely) and HbA1c change in the two years prior to insulin therapy (p &lt; 0.001). Patients that lost weight parallel with HbA1c rise in the two-years pre-insulin, showed the most pronounced weight gain. Of these patients, roughly one out of five (20.3%) gained 5 kg weight or more.CONCLUSIONS: Clinicians and patients should be alert for excessive weight gain after initiation of insulin, in the case of weight loss prior to insulin therapy initiation, particularly with increasing and prolonged high HbA1c at (and after) insulin initiation.</p

AGN Black Hole Masses and Bolometric Luminosities

Black hole mass, along with mass accretion rate, is a fundamental property of active galactic nuclei. Black hole mass sets an approximate upper limit to AGN energetics via the Eddington limit. We collect and compare all AGN black hole mass estimates from the literature; these 177 masses are mostly based on the virial assumption for the broad emission lines, with the broad-line region size determined from either reverberation mapping or optical luminosity. We introduce 200 additional black hole mass estimates based on properties of the host galaxy bulges, using either the observed stellar velocity dispersion or using the fundamental plane relation to infer $\sigma$; these methods assume that AGN hosts are normal galaxies. We compare 36 cases for which black hole mass has been generated by different methods and find, for individual objects, a scatter as high as a couple of orders of magnitude. The less direct the method, the larger the discrepancy with other estimates, probably due to the large scatter in the underlying correlations assumed. Using published fluxes, we calculate bolometric luminosities for 234 AGNs and investigate the relation between black hole mass and luminosity. In contrast to other studies, we find no significant correlation of black hole mass with luminosity, other than those induced by circular reasoning in the estimation of black hole mass. The Eddington limit defines an approximate upper envelope to the distribution of luminosities, but the lower envelope depends entirely on the sample of AGN included. For any given black hole mass, there is a range in Eddington ratio of up to three orders of magnitude.Comment: 43 pages with 10 figures. Accepted for publication in Ap

Course of body weight before and after the initiation of insulin therapy in type 2 diabetes mellitus:Retrospective inception cohort study (ZODIAC 58)

Aims: The aim of this study was to explore the effect of insulin treatment initiation on weight by taking weight change prior to initiation into account. Materials and methods: We performed an observational retrospective inception cohort study, concerning Dutch primary care. We identified all patients that initiated insulin treatment (n = 7967) and individually matched patients with a reference patient (n = 5213 pairs). We obtained estimated mean weight changes in the five years prior to five years post insulin therapy. We applied linear regression analysis on weight change in the first year after insulin therapy (T0 to T+1), with matched group as primary determinant adjusted for pre-insulin weight change and additional covariates. Results: Estimated mean weight increased in the five consecutive years prior to insulin therapy (-0.23 kg in year T-5 to T-4, 0.01 kg in year T-4 to T-3, 0.07 kg in year T-3 to T-2, 0.24 kg in year T-2 to T-1, and 0.46 kg in year T-1 to T0) and continued to increase in the first year after, that is T0 to T+1, at a slightly lower rate (0.31 ± 3.9 kg). Pre-insulin weight change had the highest explained variance and was inversely and independently associated with weight change (p < .001). Starting insulin was associated with weight increase, independent of pre-insulin weight change (β-adjusted 1.228, p < .001). Stratification revealed that despite having a more or less similar baseline BMI, patients with substantial weight increase showed higher estimated mean BMI's followed by weight loss pre-insulin. In matched references, estimated mean weight changes were negative in all years concerning the study period, indicating consistent weight loss. Conclusions: Initiation of insulin therapy was independently associated with weight increase; however, overall effect on weight was small and subject to substantial variation. Pre-insulin weight change is identified as a relatively strong inverse determinant of weight change after insulin initiation