1,285 research outputs found

    Arms tracing: perspectives on control, traffic and use of illegal weapons in Colombia

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    The publication reports on an extensive research endeavour to screen small arms stockpiles that were seized from illicit non-state actors in Colombia in the course of the past 5 years. It determines the proportion of these arms that are of European Union origin and reconstructs these arms flows 'upstream', so as to assess whether and to what extent these arms have been subject to unauthorized re-exports by states that obtained the arms legally from European Union member states

    Rastreo de Armas: Perspectivas sobre control, tráfico y uso de armas ilegales en Colombia

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    The publication reports on an extensive research endeavour to screen small arms stockpiles that were seized from illicit non-state actors in Colombia in the course of the past 5 years. It determines the proportion of these arms that are of European Union origin and reconstructs these arms flows 'upstream', so as to assess whether and to what extent these arms have been subject to unauthorized re-exports by states that obtained the arms legally from European Union member states

    Three-dimensional printed polycaprolactone-microcrystalline cellulose scaffolds

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    Microcrystalline cellulose (MCC) is proposed in this study as an additive in polycaprolactone (PCL) matrices to obtain three-dimensional (3D) printed scaffolds with improved mechanical and biological properties. Improving the mechanical behavior and the biological performance of polycaprolactone-based scaffolds allows to increase the potential of these structures for bone tissue engineering. Different groups of samples were evaluated in order to analyze the effect of the additive in the properties of the PCL matrix. The concentrations of MCC in the groups of samples were 0, 2, 5, and 10% (w/w). These combinations were subjected to a thermogravimetric analysis in order to evaluate the influence of the additive in the thermal properties of the composites. 3D printed scaffolds were manufactured with a commercial 3D printer based on fused deposition modelling. The operation conditions have been established in order to obtain scaffolds with a 0/90° pattern with pore sizes between 450 and 500 µm and porosity values between 50 and 60%. The mechanical properties of these structures were measured in the compression and flexural modes. The scaffolds containing 2 and 5% MCC have higher flexural and compression elastic modulus, although those containing 10% do not show this reinforcement effect. On the other hand, the proliferation of sheep bone marrow cells on the proposed scaffolds was evaluated over 8 days. The results show that the proliferation is significantly better (p < 0.05) on the group of samples containing 2% MCC. Therefore, these scaffolds (PCL:MCC 98:2) have suitable properties to be further evaluated for bone tissue engineering applications

    The Parental Concerns Questionnaire: A Brief Screening Instrument for Potentially Severe Behavior Problems in Infants and Toddlers At-Risk for Developmental Delays

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    The Parental Concerns Questionnaire (PCQ) was designed as a parent-interview screening instrument for young children with developmental concerns at risk for potentially severe behavior problems (SBDs). Parents of 262 young children (4 to 48 months) answered to the 15 dichotomous PCQ items interviewed by trained staff. Cluster analysis for items revealed three item clusters, which we labeled Developmental/Social (8 items), Biomedical (3 items), and Behavior Problems (3 items). This paper discussed primarily the Behavior Problems cluster, with items referring to self-injurious, aggressive, and destructive behaviors. Parents' concerns about behavior problems were high, with item-endorsements of the Behavior Problems cluster ranging from 41.8 % to 68.8 %. The Behavior Problems cluster was significantly correlated with all three subscales of the Behavior Problems Inventory (BPI-01), with select subscales of the Aberrant Behavior Checklist (ABC), and with the Repetitive Behavior Scale-Revised (RBS-R) providing some evidence for concurrent validity. Sensitivity and specificity data were computed for the three PCQ items as well as for the cluster score in comparison with the BPI-01, ABC, and RBS-R showing strong sensitivity. The PCQ Behavior Problems cluster is a useful screening checklist with high sensitivity for potential SBDs in young children at-risk for developmental delays

    Neutron-proton bremsstrahlung from intermediate energy heavy-ion reactions as a probe of the nuclear symmetry energy?

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    Hard photons from neutron-proton bremsstrahlung in intermediate energy heavy-ion reactions are examined as a potential probe of the nuclear symmetry energy within a transport model. Effects of the symmetry energy on the yields and spectra of hard photons are found to be generally smaller than those due to the currently existing uncertainties of both the in-medium nucleon-nucleon cross sections and the photon production probability in the elementary process pnpnγpn\to pn\gamma. Very interestingly, nevertheless, the ratio of hard photon spectra R1/2(γ)R_{1/2}(\gamma) from two reactions using isotopes of the same element is not only approximately independent of these uncertainties but also quite sensitive to the symmetry energy. For the head-on reactions of 132Sn+124Sn^{132}Sn+^{124}Sn and 112Sn+112Sn^{112}Sn+^{112}Sn at Ebeam/A=50E_{beam}/A=50 MeV, for example, the R1/2(γ)R_{1/2}(\gamma) displays a rise up to 15% when the symmetry energy is reduced by about 20% at ρ=1.3ρ0\rho=1.3\rho_0 which is the maximum density reached in these reactions.Comment: Added new results in Fig. 6 and new references [27.28]. Phys. Lett. B in pres

    Identification of children who may benefit from self-hypnosis at a pediatric pulmonary center

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    BACKGROUND: Emotional difficulties can trigger respiratory symptoms. Thus, children presenting with respiratory complaints may benefit from a psychological intervention. The purpose of this study was to define the proportion of patients referred to a Pediatric Pulmonary Center who may benefit from instruction in self-hypnosis, as a psychological intervention. METHODS: A retrospective chart review was conducted for all newly referred patients to the SUNY Upstate Medical University Pediatric Pulmonary Center during an 18 month period beginning January 1, 2000. Patients were offered hypnosis if they presented with symptoms or signs suggestive of psychological difficulties. Hypnosis was taught in one or two 15–45 minute sessions by a pediatric pulmonologist. RESULTS: Of 725 new referrals, 424 were 0–5 years old, 193 were 6–11 years old, and 108 were 12–18 years old. Diagnoses of anxiety, habit cough, or vocal cord dysfunction accounted for 1% of the 0–5 year olds, 20% of the 6–11 year olds, and 31% of the 12–18 year olds. Hypnotherapy was offered to 1% of 0–5 year olds, 36% of 6–11 year olds, and 55% of 12–18 year olds. Of 81 patients who received instruction in self-hypnosis for anxiety, cough, chest pain, dyspnea, or inspiratory difficulties, 75% returned for follow-up, and among the returning patients 95% reported improvement or resolution of their symptoms. CONCLUSION: A large number of patients referred to a Pediatric Pulmonary Center appeared to benefit from instruction in self-hypnosis, which can be taught easily as a psychological intervention

    The low level of debris disk activity at the time of the Late Heavy Bombardment: a Spitzer study of Praesepe

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    We present 24 micron photometry of the intermediate-age open cluster Praesepe. We assemble a catalog of 193 probable cluster members that are detected in optical databases, the Two Micron All Sky Survey (2MASS), and at 24 micron, within an area of ~ 2.47 square degrees. Mid-IR excesses indicating debris disks are found for one early-type and for three solar-type stars. Corrections for sampling statistics yield a 24 micron excess fraction (debris disk fraction) of 6.5 +- 4.1% for luminous and 1.9 +- 1.2% for solar-type stars. The incidence of excesses is in agreement with the decay trend of debris disks as a function of age observed for other cluster and field stars. The values also agree with those for older stars, indicating that debris generation in the zones that emit at 24 micron falls to the older 1-10 Gyr field star sample value by roughly 750 Myr. We discuss our results in the context of previous observations of excess fractions for early- and solar-type stars. We show that solar-type stars lose their debris disk 24 micron excesses on a shorter timescale than early-type stars. Simplistic Monte Carlo models suggest that, during the first Gyr of their evolution, up to 15-30% of solar-type stars might undergo an orbital realignment of giant planets such as the one thought to have led to the Late Heavy Bombardment, if the length of the bombardment episode is similar to the one thought to have happened in our Solar System. In the Appendix, we determine the cluster's parameters via boostrap Monte Carlo isochrone fitting, yielding an age of 757 Myr (+- 36 Myr at 1 sigma confidence) and a distance of 179 pc (+- 2 pc at 1 sigma confidence), not allowing for systematic errors.Comment: 22 pages, 14 figures, 9 tables, emulateapj format; Accepted for publication in The Astrophysical Journa

    The generalized Hamiltonian model for the shafting transient analysis of the hydro turbine generating sets.

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    yesTraditional rotor dynamics mainly focuses on the steady- state behavior of the rotor and shafting. However, for systems such as hydro turbine generating sets (HTGS) where the control and regulation is frequently applied, the shafting safety and stabilization in transient state is then a key factor. The shafting transient state inevitably involves multiparameter domain, multifield coupling, and coupling dynamics. In this paper, the relative value form of the Lagrange function and its equations have been established by defining the base value system of the shafting. Takingthe rotation angle and the angular speed of the shafting as a link, the shafting lateral vibration and generator equations are integrated into the framework of generalized Hamiltonian system. The generalized Hamiltonian control model is thus established. To make the model more general, additional forces of the shafting are taken as the input excitation in proposed model. The control system of the HTGS can be easily connected with the shafting model to form the whole simulation system of the HTGS. It is expected that this study will build a foundation for the coupling dynamics theory using the generalized Hamiltonian theory to investigate coupling dynamic mechanism among the shafting vibration, transient of hydro turbine generating sets, and additional forces of the shafting.National Natural Science Foundation of China under Grant Nos. 51179079 and 5083900
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