Chaotic communication based on the particle-in-a-box electronic circuit

A secure communication system based on the error-feedback synchronization of the electronic model of the particle-in-a-box system is proposed. This circuit allows a robust and simple electronic emulation of the mechanical behavior of the collisions of a particle inside a box, exhibiting rich chaotic behavior. The required nonlinearity to emulate the box walls is implemented in a simple way when compared with other analog electronic chaotic circuits. A master/slave synchronization of two circuits exhibiting a rich chaotic behavior demonstrates the potentiality of this system to secure communication. In this system, binary data stream information modulates the bifurcation parameter of the particle-in-a-box electronic circuit in the transmitter. In the receiver circuit, this parameter is estimated using Pecora-Carroll synchronization and error-feedback synchronization. The performance of the demodulation process is verified through the eye pattern technique applied on the recovered bit stream. During the demodulation process, the error-feedback synchronization presented better performance compared with the Pecora-Carroll synchronization. The application of the particle-in-a-box electronic circuit in a secure communication system is demonstrated.

A reference business process for ecological niche modelling

Ecological niche modelling combines species occurrence points with environmental raster layers in order to obtain models for describing the probabilistic distribution of species. The process to generate an ecological niche model is complex. It requires dealing with a large amount of data, use of different software packages for data conversion, for model generation and for different types of processing and analyses, among other functionalities. A software platform that integrates all requirements under a single and seamless interface would be very helpful for users. Furthermore, since biodiversity modelling is constantly evolving, new requirements are constantly being added in terms of functions, algorithms and data formats. This evolution must be accompanied by any software intended to be used in this area. In this scenario, a Service-Oriented Architecture (SOA) is an appropriate choice for designing such systems. According to SOA best practices and methodologies, the design of a reference business process must be performed prior to the architecture definition. The purpose is to understand the complexities of the process (business process in this context refers to the ecological niche modelling problem) and to design an architecture able to offer a comprehensive solution, called a reference architecture, that can be further detailed when implementing specific systems. This paper presents a reference business process for ecological niche modelling, as part of a major work focused on the definition of a reference architecture based on SOA concepts that will be used to evolve the openModeller software package for species modelling. The basic steps that are performed while developing a model are described, highlighting important aspects, based on the knowledge of modelling experts. In order to illustrate the steps defined for the process, an experiment was developed, modelling the distribution of Ouratea spectabilis (Mart.) Engl. (Ochnaceae) using openModeller. As a consequence of the knowledge gained with this work, many desirable improvements on the modelling software packages have been identified and are presented. Also, a discussion on the potential for large-scale experimentation in ecological niche modelling is provided, highlighting opportunities for research. The results obtained are very important for those involved in the development of modelling tools and systems, for requirement analysis and to provide insight on new features and trends for this category of systems. They can also be very helpful for beginners in modelling research, who can use the process and the experiment example as a guide to this complex activity. (c) 2008 Elsevier B.V. All rights reserved.

Novel blue emitters based on pi-conjugated block copolymers

A series of new phenyl-based conjugated copolymers has been synthesized and investigated by vibrational and photoluminescence spectroscopy (PL). The materials are: poly( 1,4-phenylene-alt-3,6-pyridazine) (COP-PIR), poly(9,9-dioctylfluorene)-co-quaterphenylene (COP-PPP) and poly[(1,4-phenylene-alt-3,6-pyridazine)-co-(1,4-phenylene-alt-9,9-dioctylfluorene)] (COP-PIR-FLUOR), with 3.5% of fluorene. COP-PPP and COP-PIR-FLUOR have high fluorescence quantum yields in solution. Infrared and Raman spectra were used to check the chemical structure of the compounds. The copolymers exhibit blue emission ranging front 2.8 to 3.6 eV when excited at E(exc)=4.13 eV. Stokes-shift Values were estimated on pristine samples in their condensed state from steady-state PL-emission and PL-excitation spectra. They suggest a difference in the torsional angle between the molecular configuration of the polymer blocks at the absorption and PL transitions and also in the photoexcitation diffusion. Additionally, the time-resolved PL of these materials has been investigated by using 100 fs laser pulses at E(exc)=4.64 eV and a streak camera. Results show very fast biexponential kinetics for the two fluorene-based polymers with decay times below 300 ps indicating both intramolecular, fast radiative recombination and migration of photogenerated electron-hole pairs. By contrast, the PL of COP-PIR is less intense and longer lived, indicating that excitons are confined to the chains in this polymer. (C) 2008 Elsevier B.V. All rights reserved.

A new technique to control brushless motor for blood pump application

This article presents a back-electromotive force (BEMF)-based technique of detection for sensorless brushless direct current motor (BLDCM) drivers. The BLDCM has been chosen as the energy converter in rotary or pulsatile blood pumps that use electrical motors for pumping. However, in order to operate properly, the BLDCM driver needs to know the shaft position. Usually, that information is obtained through a set of Hall sensors assembled close to the rotor and connected to the electronic controller by wires. Sometimes, a large distance between the motor and controller makes the system susceptible to interference on the sensor signal because of winding current switching. Thus, the goal of the sensorless technique presented in this study is to avoid this problem. First, the operation of BLDCM was evaluated on the electronic simulator PSpice. Then, a BEMF detector circuitry was assembled in our laboratories. For the tests, a sensor-dependent system was assembled where the direct comparison between the Hall sensors signals and the detected signals was performed. The obtained results showed that the output sensorless detector signals are very similar to the Hall signals at speeds of more than 2500 rpm. Therefore, the sensorless technique is recommended as a responsible or redundant system to be used in rotary blood pumps.

Cardiovascular Simulator Improvement: Pressure Versus Volume Loop Assessment

This article presents improvement on a physical cardiovascular simulator (PCS) system. Intraventricular pressure versus intraventricular volume (PxV) loop was obtained to evaluate performance of a pulsatile chamber mimicking the human left ventricle. PxV loop shows heart contractility and is normally used to evaluate heart performance. In many heart diseases, the stroke volume decreases because of low heart contractility. This pathological situation must be simulated by the PCS in order to evaluate the assistance provided by a ventricular assist device (VAD). The PCS system is automatically controlled by a computer and is an auxiliary tool for VAD control strategies development. This PCS system is according to a Windkessel model where lumped parameters are used for cardiovascular system analysis. Peripheral resistance, arteries compliance, and fluid inertance are simulated. The simulator has an actuator with a roller screw and brushless direct current motor, and the stroke volume is regulated by the actuator displacement. Internal pressure and volume measurements are monitored to obtain the PxV loop. Left chamber internal pressure is directly obtained by pressure transducer; however, internal volume has been obtained indirectly by using a linear variable differential transformer, which senses the diaphragm displacement. Correlations between the internal volume and diaphragm position are made. LabVIEW integrates these signals and shows the pressure versus internal volume loop. The results that have been obtained from the PCS system show PxV loops at different ventricle elastances, making possible the simulation of pathological situations. A preliminary test with a pulsatile VAD attached to PCS system was made.

Oral lesions in 166 patients with cutaneous psoriasis: A controlled study

Objectives. This study was aimed to test if the frequency of oral lesions bears statistical correlation or not with the condition of cutaneous psoriasis. Study design. Two groups were examined, one made up of 166 patients with skin psoriasis and the other with the same number of individuals with a negative history of skin diseases (control group), matched by age, race, and sex. Patients with psoriasis were grouped according to their having localized or generalized forms of the disease. The oral mucosa was thoroughly examined in both groups. Data were analyzed using chi-square test, Fisher`s test, the odds ratio (OR) with a 95% confidence interval (CI), and the Ryan-Holm step-down Bonferroni procedure. The overall significance was set at P <= 0.05. Results. The oral lesions significantly associated with psoriasis were fissured tongue (FT, OR=2.7; 95% CI: 1.3-5.6), and geographic tongue (GT, OR=5.0; 95% CI: 1.5-16.8). Other factors analyzed, such as topical and/or systemic medication for treatment of psoriasis versus nontreated patients, and localized versus generalized forms of psoriasis presented no statistical association with the frequency of FT or GT lesions (P > 0.05). Conclusions. Patients with psoriasis presented no specific oral lesion different from those seen in the control group. Although further investigation is warranted to establish whether or not either FT or GT can be characterized as an oral expression of psoriasis, the present investigation did find for both these types of lesions that the frequency of each bore a statistically significant relation with the presence of cutaneous psoriasis.

Poly(ethylene glycol) decorated poly(methylmethacrylate) nanoparticles for protein adsorption

Poly(ethylene glycol) decorated poly( methyl methacrylate) particles were synthesized by means of emulsion polymerization using poly(ethylene glycol) sorbitan monolaurate (Tween-20) as surfactant. PMMA/PEG particles presented mean diameter (195 +/- 15) nm, indicating narrow size distribution. The adsorption behavior of bovine serum albumin (BSA) and concanavalin A (ConA) onto PMMA/PEG particles was investigated by means of spectrophotometry. Adsorption isotherms obtained for BSA onto PMMA/PEG particles fitted well sigmoidal function, which is typical for multilayer adsorption. Con A adsorbed irreversibly onto PMMA/PEG particles. The efficiency of ConA covered particles to induce dengue virus quick agglutination was evaluated. (C) 2010 Elsevier B.V. All rights reserved.

Mechanical behavior of prosthesis in Toucan beak (Ramphastos toco)

The purpose of this study is to characterize the structure of the beak of Toco Toucan (Ramphastos toco) and to investigate means for arresting fractures in the rhinotheca using acrylic resin. The structure of the rhamphastid bill has been described as a sandwich structured composite having a thin exterior comprised of keratin and a thick foam core constructed of mineralized collagenous rods (trabeculae). The keratinous rhamphotheca consists of superposed polygonal scales (approximately 50 pm in diameter and 1 mu m in thickness). In order to simulate the orientation of loading to which the beak is subjected during exertion of bite force, for example, we conducted flexure tests on the dorso-ventral axis of the maxilla. The initially intact (without induced fracture) beak fractured in the central portion when subjected to a force of 270 N, at a displacement of 23 mm. The location of this fracture served as a reference for the fractures induced in other beaks tested. The second beak was fractured and repaired by applying resin on both lateral surfaces. The repaired maxilla sustained a force of 70 N with 6.5 mm deflection. The third maxilla was repaired similarly except that it was conditioned in acid for 60s prior to fixation with resin. It resisted a force of up to 63 N at 6 mm of deflection. The experimental results were compared with finite element calculations for unfractured beak in bending configuration. The repaired specimens were found to have strength equal to only one third of the intact beak. Finite element simulations allow visualization of how the beak system (sandwich shell and cellular core) sustains high flexural strength. (C) 2010 Elsevier B.V. All rights reserved.

LH surge in Nelore cows (Bos indicus), after induced estrus or after ovarian superestimulation

Considering, that there is limited information about the preovulatory LH surge in Zebu Cattle (Bos indicus). the purpose of the present work was to assess the LH surge in Nelore cows during the estrous cycle and after ovarian superestimulation of ovarian follicular development with FSH. This information is particularly important to improve superovulatory protocols associated with fixed-time artificial insemination. Nelore cows (n = 12) had their estrus synchronized with all intravaginal device containing progesterone (CIDR-B (R)) associated with estradiol benzoate administration (EB, 2.5 mg, i.m., Day 0). Eight days later all animals were treated with PGF2 alpha (Day 8) in the morning (8:00 h) and at night, when CIDR devices were removed (20:00 11). Starting 38 h after the first PGF2 alpha injection, blood sampling and ovarian ultrasonography took place every 4 h, during 37 consecutive hours. Frequent handling may have resulted in a stress-induced suppression of LH secretion resulting in only 3 of 12 cows having ovulations at 46.7 +/- 4.9 and 72.3 +/- 3.8 h, respectively, after removal of CIDR-B. Thirty days later, the same animals received the described hormonal treatment associated with FSH (Folltropin (R) total dose = 200 mg) administered twice a day, during 4 consecutive days, starting on Day 5. Thirty-six hours after the first injection of PGF2 alpha, to minimize stress. only seven blood samples were collected at 4 h interval each. and ultrasonography was performed every 12 h until ovulation. In 11 of 12 cows (92%) the LH surge and ovulation were observed 34.6 +/- 1.6 and 59.5 +/- 1.9 h. respectively. after removal of progesterone source. The maximum values for LH in those animals were 19.0 +/- 2.6 ng/ml (mean +/- S.E.M.). It is concluded that, in Nelore COWS submitted to a ovarian superstimulation Protocol, the LH surge occurs approximately 35 It after removal of intravaginal device containing progesterone, and approximately 12h before the LH surge observed after an induced estrus without ovarian superstimulation (C) 2008 Elsevier B.V. All rights reserved.

Perception or synthesized voice quality in connected speech by Cantonese speakers

Perceptual voice analysis is a subjective process. However, despite reports of varying degrees of intrajudge and interjudge reliability, it is widely used in clinical voice evaluation. One of the ways to improve the reliability of this procedure is to provide judges with signals as external standards so that comparison can be made in relation to these anchor signals. The present study used a Klatt speech synthesizer to create a set of speech signals with varying degree of three different voice qualities based on a Cantonese sentence. The primary objective of the study was to determine whether different abnormal voice qualities could be synthesized using the built-in synthesis parameters using a perceptual study. The second objective was to determine the relationship between acoustic characteristics of the synthesized signals and perceptual judgment. Twenty Cantonese-speaking speech pathologists with at least three years of clinical experience in perceptual voice evaluation were asked to undertake two tasks. The first was to decide whether the voice quality of the synthesized signals was normal or not. The second was to decide whether the abnormal signals should be described as rough, breathy, or vocal fry. The results showed that signals generated with a small degree of aspiration noise were perceived as breathiness while signals with a small degree of flutter or double pulsing were perceived as roughness. When the flutter or double pulsing increased further, tremor and vocal fry, rather than roughness, were perceived. Furthermore, the amount of aspiration noise, flutter, or double pulsing required for male voice stimuli was different from that required for the female voice stimuli with a similar level of perceptual breathiness and roughness. These findings showed that changes in perceived vocal quality could be achieved by systematic modifications of synthesis parameters. This opens up the possibility of using synthesized voice signals as external standards or anchors to improve the reliability of clinical perceptual voice evaluation. (C) 2002 Acoustical Society of America.

Organizational responses to a changing aid environment: the German Agency for Technical Cooperation (GTZ)

As a major European donor, German government development assistance faces a series of challenges. Recent political changes have raised expectations for demonstrable health outcomes as a result of German development assistance; there has been a deepened commitment to collaboration with other bilateral and multilateral donors; and partner countries are increasingly open to new approaches to development. German development assistance also reflects a new ethos of partnership and the shift to programmatic and sector based development approaches. At the same time, its particular organizational structure and administrative framework highlight the extent of structural and systems reforms required of donors by changing development relationships, and the tensions created in responding to these. This paper examines organizational changes within the German Agency for Technical Cooperation (Deutsche Gesellschaft fur Technische Zusammenarbeit) (GTZ), aimed at increasing its Regional, Sectoral, Managerial and Process competence as they affect health and related sectors. These include the decentralization of GTZ, the trend to integration of projects, the increasing focus on policy and health systems reform, increased inter-sectoral collaboration, changes in recruitment and training, new perspectives in planning and evaluation and the introduction of a quality management programme. Copyright (C) 2002 John Wiley Sons, Ltd.

The rhetoric of sector-wide approaches for health development

The past decade has witnessed an increasing concerns over the effectiveness of project-based development assistance and the promotion of sector-wide approaches (SWAps) to health as a means to increase donor collaboration, consolidate local management of resources and undertake the policy and systems reform necessary to achieve a greater impact on health issues. The concept has gained the support of both the World Bank and the World Health Organisation, as well as key bilateral donors, and dominates current initiatives in development assistance for health. This paper examines the proposal of SWAps as rhetoric, and seeks to understand how that rhetoric functions, despite the variable application of its constituent elements and the range of contexts in which it operates. (C) 2002 Elsevier Science Ltd. All rights reserved.

The pyramidal cell of the sensorimotor cortex of the macaque monkey: Phenotypic variation

Recent studies have revealed striking differences in pyramidal cell structure among cortical regions involved in the processing of different functional modalities. For example, cells involved in visual processing show systematic variation, increasing in morphological complexity with rostral progression from V1 through extrastriate areas. Differences have also been identified between pyramidal cells in somatosensory, motor and prefrontal cortex, but the extent to which the pyramidal cell phenotype may vary between these functionally related cortical regions remains unknown. In the present study we investigated the structure of layer III pyramidal cells in somatosensory and motor areas 3b, 4, 5, 6 and 7b of the macaque monkey. Cells were intracellularly injected in fixed, flat-mounted cortical slices and analysed for morphometric parameters. The size of the basal dendritic arbours, the number of their branches and their spine density were found to vary systematically between areas. Namely, we found a trend for increasing complexity in dendritic arbour structure through areas 3b, 5 and 7b. A similar trend occurred through areas 4 and 6. The differences in arbour structure may determine the number of inputs received by neurons and may thus be an important factor in determining function at the cellular and systems level.

Perceptions of evidence-based practice: A survey of Australian occupational therapists

Evidence-based practice (EBP) requires clinicians to access, appraise and integrate research literature with clinical experience and clients' perspectives. Currently, little is known about occupational therapists' attitudes to EBP, their perception of implementation barriers or their educational needs. A questionnaire reflecting these issues was sent to a proportionate random sample of 1491 members of the national professional occupational therapy association, OT AUSTRALIA. The questionnaire was completed by 649 (44%) participants. Occupational therapists were positive about EBP with most (96%) agreeing that EBP is important to occupational therapy. Although 56% used research to make clinical decisions, more relied on clinical experience (96%), information from continuing education (82%) and colleagues (80%). Lack of time, evidence and skills were identified as the main barriers to the implementation of EBP. Over half (52%) expressed strong interest in EBP skills training, and most (80%) indicated an interest in the availability of brief summaries of evidence. Targeted educational initiatives, resources and systems are needed to support EBP in occupational therapy.

Organiza????es virtuais no setor p??blico: uma nova abordagem

?? crescente o envolvimento de organiza????es p??blicas e privadas com alian??as e parcerias. No novo cen??rio colaborativo, uma nova abordagem para o planejamento das organiza????es precisa ser desenvolvida, com especial aten????o para o setor p??blico, em cujo ambiente a escassez de recursos pode ser total ou parcialmente suprida pela cria????o ou incremento de redes entre organiza????es e sistemas. A nova abordagem para a coordena????o interorganizacional no ??mbito do planejamento governamental pode resultar em algum tipo de ???organiza????o virtual??? para o setor p??blico, ?? semelhan??a do que j?? ocorre no setor privado. O artigo destaca a import??ncia da reflex??o sobre as implica????es e possibilidades que os conceitos relativos a organiza????es virtuais podem trazer para a coordena????o interorganizacional no ??mbito do planejamento governamental, de forma a contribuir para incrementar a efetividade da a????o de governo, por meio de ambiente informacional cooperativo. Aspectos como cultura organizacional, poder e controle, fronteiras e estruturas organizacionais, confian??a e gest??o cooperativa da informa????o dever??o ser observados no contexto do planejamento governamental, caso se pretenda evoluir na aplica????o do conceito de organiza????es virtuais no setor p??blico