Population ageing in the Caribbean: a four country study

Includes bibliography

Disability in the Caribbean. A study of four countries: a socio-demographic analysis of the disabled

Includes bibliography

Chemical and biological characterization of four new linear cationic α-helical peptides from the venoms of two solitary eumenine wasps

Four novel peptides were isolated from the venoms of the solitary eumenine wasps Eumenes rubrofemoratus and Eumenes fraterculus. Their sequences were determined by MALDI-TOF/TOF (matrix assisted laser desorption/ionization time-of-flight mass spectrometry) analysis, Edman degradation and solid-phase synthesis. Two of them, eumenitin-R (LNLKGLIKKVASLLN) and eumenitin-F (LNLKGLFKKVASLLT), are highly homologous to eumenitin, an antimicrobial peptide from a solitary eumenine wasp, whereas the other two, EMP-ER (FDIMGLIKKVAGAL-NH 2) and EMP-EF (FDVMGIIKKIAGAL-NH 2), are similar to eumenine mastoparan-AF (EMP-AF), a mast cell degranulating peptide from a solitary eumenine wasp. These sequences have the characteristic features of linear cationic cytolytic peptides; rich in hydrophobic and basic amino acids with no disulfide bond, and accordingly, they can be predicted to adopt an amphipathic α-helix secondary structure. In fact, the CD (circular dichroism) spectra of these peptides showed significant α-helical conformation content in the presence of TFE (trifluoroethanol), SDS (sodium dodecylsulfate) and asolectin vesicles. In the biological evaluation, all the peptides exhibited a significant broad-spectrum antimicrobial activity, and moderate mast cell degranulation and leishmanicidal activities, but showed virtually no hemolytic activity. © 2011 Elsevier Ltd.

3-D Space Vector PWM implementation for Four-Leg Voltage Source Inverter

The Space Vector PWM implementation and operation for a Four-leg Voltage Source Inverter (VSI) is detailed and discussed in this paper. Although less common, four-leg VSIs are a viable solution for situations where neutral connection is necessary, including Active Power Filter applications. This topology presents advantages regarding the VSI DC link and capacitance, which make it useful for high power devices. Theory, implementation and simulations are also discussed in this paper. © 2011 IEEE.

Comparative analysis for reactive energy measurement methodologies, under non-sinusoidal conditions in three-phase four-wire circuits

This paper presents some methodologies for reactive energy measurement, considering three modern power theories that are suitable for three-phase four-wire non-sinusoidal and unbalanced circuits. The theories were applied in some profiles collected in electrical distribution systems which have real characteristics for voltages and currents measured by commercial reactive energy meters. The experimental results are presented in order to analyze the accuracy of the methodologies, considering the standard IEEE 1459-2010 as a reference. Finally, for additional comparisons, the theories will be confronted with the modern Yokogawa WT3000 energy meter and three samples of a commercial energy meter through an experimental setup. © 2011 IEEE.

Envejecimiento: cuatro facetas de una sociedad para todas las edades = Ageing: four dimensions of a society for all ages

Incluye Bibliografía

Networked control system for the guidance of a four-wheel steering agricultural robotic platform

A current trend in the agricultural area is the development of mobile robots and autonomous vehicles for precision agriculture (PA). One of the major challenges in the design of these robots is the development of the electronic architecture for the control of the devices. In a joint project among research institutions and a private company in Brazil a multifunctional robotic platform for information acquisition in PA is being designed. This platform has as main characteristics four-wheel propulsion and independent steering, adjustable width, span of 1,80m in height, diesel engine, hydraulic system, and a CAN-based networked control system (NCS). This paper presents a NCS solution for the platform guidance by the four-wheel hydraulic steering distributed control. The control strategy, centered on the robot manipulators control theory, is based on the difference between the desired and actual position and considering the angular speed of the wheels. The results demonstrate that the NCS was simple and efficient, providing suitable steering performance for the platform guidance. Even though the simplicity of the NCS solution developed, it also overcame some verified control challenges in the robot guidance system design such as the hydraulic system delay, nonlinearities in the steering actuators, and inertia in the steering system due the friction of different terrains. Copyright © 2012 Eduardo Pacincia Godoy et al.

The design of the Latin American Documentation System (DOCPAL); a report on the first four months

Includes bibliography

Export processing in the Caribbean: lessons from four case studies

Includes bibliography

Tjon Lines and Scaling Limit in Four-Body Systems

The fixed-slope correlation between tetramer and trimer binding energies, observed by Tjon in the context of nuclear physics, is mainly a manifestation of the dominance of the two-nucleon force in the nuclear potential, which makes the four-body scale on the order of the three-body one. In a more general four-boson case, the correlation between tetramer and trimer binding energies has a non-fixed slope, which expresses the dependence on the new scale. The associated scaling function generates a family of Tjon lines. This conclusion relies on a recent study with weakly-bound four identical bosons, within a renormalized zero-range Faddeev-Yakubovsky formalism. © 2012 Springer-Verlag.

Universality in Four-Boson Systems

We report recent advances on the study of universal weakly bound four-boson states from the solutions of the Faddeev-Yakubovsky equations with zero-range two-body interactions. In particular, we present the correlation between the energies of successive tetramers between two neighbor Efimov trimers and compare it to recent finite range potential model calculations. We provide further results on the large momentum structure of the tetramer wave function, where the four-body scale, introduced in the regularization procedure of the bound state equations in momentum space, is clearly manifested. The results we are presenting confirm a previous conjecture on a four-body scaling behavior, which is independent of the three-body one. We show that the correlation between the positions of two successive resonant four-boson recombination peaks are consistent with recent data, as well as with recent calculations close to the unitary limit. Systematic deviations suggest the relevance of range corrections. © 2012 Springer-Verlag.

Frequency of reported European ancestry among multiple sclerosis patients from four cities in the southern and southeastern regions of Brazil

Recent reports on the prevalence of multiple sclerosis (MS) have described discrepancies between the rates in cities in the northeastern and southeastern regions of Brazil, representing a north-south gradient. European immigrants settled in southeastern and southern Brazil at the beginning of the twentieth century. In this study, we report the frequency of European ancestors among Brazilian MS patients in four cities in the southern and southeastern regions of Brazil. Methods: A total of 652 consecutive patients with confirmed MS diagnoses seen at four centers in Belo Horizonte, Ribeirão Preto, Londrina and Santos were asked about the origin of their ancestors, going back three generations. Results: 287 (44%) reported Italian ancestry, 211 (32%) reported that all ancestors were born in Brazil, 49 (7.5%) had Portuguese ancestry and 70 (10%) had Spanish ancestry. The patients in Belo Horizonte and Londrina reported higher proportions of Italian ancestry than the proportions estimated for the populations of their respective States. Conclusion: Brazil has a north-south gradient of 0.91/100,000 per degree of latitude, which is higher than the gradient for Latin America. Since the largest immigrant group that settled in southern and southeastern Brazil was from Italy, it is possible that Italian immigration was one of the factors that have contributed toward increasing the prevalence of MS in these regions. © 2013 Elsevier B.V. All rights reserved.

Determination of the Real Influence of the Addition of Four Thickening Agents in Creams Using Rheological Measurements

This study aimed to characterize different emulsions obtained by the addition of four thickening agents, using rheological measurements, beyond analyzing the emulsions by polarized light microscopy looking for liquid crystals on them. The addition of these four thickening agents did not modify the base emulsion rheology, only an improvement in the sensory of the formulation was verified. The polarized light microscopy showed the formation of liquid crystalline structures in all the formulations, thus, the thickening agents did not influence in this parameter too. However, the emulsions could be considered appropriated for cosmetic purposes, probably being highly physically stable. © 2013 Copyright Taylor and Francis Group, LLC.

A prospective study on implants installed with flapless-guided surgery using the all-on-four concept in the mandible

Aim: Clinical data are scarce on flapless-guided surgery in the mandible using the all-on-four concept. In addition, limited documentation exists on the latter under immediate loading conditions with a pre-fabricated implant bridge. The aim was to provide detailed documentation focusing on clinical and radiographic outcome and complications. Material and methods: Sixteen systemically healthy non-smoking patients (10 women, 6 men, average age 59 years) with sufficient bone volume in the mandible were operated via flapless-guided surgery using the all-on-four concept. Clinical and radiographic data and complications were registered at 3, 6 and 12 months. Results: The overall implant survival rate was 90% with a trend for higher failure of short implants (P = 0.098). The mean bone level after 12 months of function was 0.83 mm with a maximum of 1.07 mm. Technical complications were common (15/16 patients). These mainly related to a misfit between the pre-fabricated prosthesis and abutment(s) (13/16 patients). Conclusion: If immediate loading of implants is pursued fabrication of the implant bridge should be based on actual impression of the implants at the time of surgery and not on their virtual position. © 2011 John Wiley & Sons A/S.