Artrópodes infestantes de plantas comercializadas em supermercados no Distrito Federal, Brasil

Many Brazilian supermarkets offer ornamental and fruit plants for sale, and many become infested by insects and other arthropods during commercialization. This work reflects the importance of knowing the pests that occur in these plants, to verify possible dissemination of these arthropods to other areas. This study was carried out with monthly visits to five supermarkets chosen at random in the Federal District, Brazil. The plants were identified and visually inspected for the presence of insects and other arthropods. The collected specimens were preserved in jars containing 70% alcohol. Their respective levels of infestation and damage were also observed and noted. Each specimen collected was identified according to specific books and keys for each taxonomic group collected. As a result, 65 plants were found to be infested with insects and mites. Of these, 48 contained sucking insects (Hemiptera) and 17 had spider mites (Tetranychus urticae Koch). Although the insects found are relatively common and have already been reported to be associated with several ornamental plants, this is the first work that records the occurrence of arthropods in ornamentals sold in commercial establishments.Os principais mercados brasileiros oferecem plantas ornamentais e frutíferas para a venda e muitas delas acabam sendo infestadas por insetos e outros artrópodes durante a comercialização. Esse trabalho reflete a importância de se conhecer as pragas que ocorrem nessas plantas, com o propósito de verificar um possível meio de disseminação desses animais para outras áreas. O presente trabalho foi realizado com visitas mensais em cinco supermercados escolhidos de forma aleatória situados no Distrito Federal, Brasil. As plantas foram identificadas e inspecionadas visualmente quanto à presença de insetos e outros artrópodes. Os espécimes coletados foram preservados em potes contendo álcool 70% e seus respectivos níveis de infestação e danos também foram observados e anotados. A identificação de cada exemplar coletado foi feita de acordo com livros e chaves específicas para cada grupo taxonômico encontrado. Como resultado, foram encontradas 65 plantas infestadas com insetos e ácaros. Destas, 48 continham insetos sugadores (Hemiptera) e 17 estavam com ácaro-rajado (Tetranychus urticae Koch). Apesar dos insetos encontrados serem relativamente comuns e já terem sido relatados associados a várias plantas ornamentais, esse é o primeiro trabalho que registra a ocorrência de artrópodes em ornamentais vendidas em estabelecimentos comerciais

Do young elite football athletes have the same strength and power characteristics as senior athletes?

An increasing number of young football athletes are competing in elite senior level competitions. However, comparison of strength, power, and speed characteristics between young elite football athletes and their senior counterparts, while controlling for anthropometric parameters, is yet to be investigated. Knee extension concentric peak torque, jump performance, and 20 m straight-line speed were compared between age groups of under 17 (U17: n = 24), under 19 (U19: n = 25), and senior (seniors: n = 19) elite, national and international level, male football athletes. Analysis of covariance was performed, with height and body mass used as covariates. No significant differences were found between age groups for knee extension concentric peak torque (p = 0.28–0.42), while an effect was observed when the covariates of height and body mass were applied (p < 0.001). Senior players had greater jump and speed performance, whereas an effect was observed only for the covariate of body mass in the 15 m and 20 m (p < 0.001) speed testing. No differences were observed between U17 and U19 groups for jump and speed performance (p = 0.26–0.46). The current study suggests that younger elite football athletes (<19 years) have lower jump and speed performance than their senior counterparts, but not for strength when height and body mass are considered as covariates. Emphasis should be on power development capacities at the late youth phase when preparing athletes for the senior competition level

TZ- VirtIO: Enabling Standardized Inter-Partition Communication in a Trustzone-Assisted Hypervisor

Virtualization technology allows the coexistence and execution of multiple operating systems on top of the same hardware platform. In the embedded systems domain, virtualization has been focused on the isolation of critical requirements like real-time, security and safety from non-critical characteristics. The strict confinement of guest partitions typically provided by virtualization does not suit the modular and inter-cooperative nature of embedded systems. The need for inter-partition communication has been addressed by multiple virtualization solutions, either to enable guest-level device para-virtualization or to ensure increased flexibility regarding cooperative partitions. However, the majority of existing approaches follow an ad hoc approach with limited to none applicability outside their solution's scope. This paper presents TZ-VirtIO, an asynchronous standardized inter-partition communication (IPC) mechanism on top of a TrustZone-assisted dual-OS hypervisor (LTZVisor). The implemented IPC uses the standard VirtIO transport layer. The experiments conducted on a physical platform show a scalable, high-bandwidth and low-overhead solution for both single-core and multi-core architectures.FCT - Fundação para a Ciência e a Tecnologia (UID/CEC/00319/2013

Towards a trustZone-assisted hypervisor for real-time embedded systems

Virtualization technology starts becoming more and more widespread in the embedded space. The penalties incurred by standard software-based virtualization is pushing research towards hardware-assisted solutions. Among the existing commercial off-the-shelf technologies for secure virtualization, ARM TrustZone is attracting particular attention. However, it is often seen with some scepticism due to the dual-OS limitation of existing state-of-the-art solutions. This letter presents the implementation of a TrustZone-based hypervisor for real-time embedded systems, which allows multiple RTOS partitions on the same hardware platform. The results demonstrate that virtualization overhead is less than 2 percent for a 10 milliseconds guest-switching rate, and the system remains deterministic. This work goes beyond related work by implementing a TrustZone-assisted solution that allows the execution of an arbitrary number of guest OSes while providing the foundation to drive next generation of secure virtualization solutions for resource-constrained embedded devices.This work has been supported by COMPETE: POCI-01-0145- FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia – (grant SFRH/BD/91530/2012 and UID/CEC/00319/2013)

HcM-FreeRTOS: hardware-centric FreeRTOS for ARM Multicore

Migration to multicore is inevitable. To harness the potential of this technology, embedded system designers need to have available operating systems (OSes) with built-in capabilities for multicore hardware. When designed to meet real-time requirements, multicore SMP (Symmetric Multiprocessing) OSes not only face the inherent problem of concurrent access to shared kernel resources, but still suffer from a bifid priority space, dictated by the co-existence of threads and interrupts.This work in progress paper presents the offloading of the FreeRTOS kernel components to a commercial-off-the-shelf (COTS) multicore hardware. The ARM Generic Interrupt Controller (GIC) is exploited to implement a multicore hardware centric version of the FreeRTOS that not only solves the priority inversion problem, but also removes the need of internal software synchronization points. Promising preliminary results on performance and determinism are presented, and the research roadmap is discussed.Sandro Pinto is supported by FCT - Fundação para a Ciência e Tecnologia (grant SFRH/BD/91530/2012). This work has been supported by FCT - Fundação para a Ciência e Tecnologia within the Project Scope: PEst-UID/CEC/00319/2013

Exploiting Template Metaprogramming to customize an object-oriented operating system

Nowadays, the growing complexity of embedded systems demands for configurability, variability and reuse. Conditional compilation and object-orientation are two of the most applied approaches in the management of system variability. While the former increases the code management complexity, the latter leverages the needed modularity and adaptability to simplify the development of reusable and customizable software at the expense of performance and memory penalty. This paper shows how C++ TMP (Template Metaprogramming) can be applied to manage the variability of an object-oriented operating system and at the same time get ride out of the performance and memory footprint overhead. In doing so, it will be statically generated only the desired functionalities, thus ensuring that code is optimized and adjusted to application requirements and hardware resources.Fundação para a Ciência e a Tecnologia (FCT

An improved public key cryptographic algorithm based on chebyshev polynomials and RSA

Due to its very desirable properties, Chebyshev polynomials are often used in the design of public key cryptographic systems. This paper discretizes the Chebyshev mapping, generalizes the properties of Chebyshev polynomials, and proposes an improved public key encryption algorithm based on Chebyshev chaotic mapping and RSA, i.e., CRPKC −Ki. This algorithm introduces alternative multiplication coefficients Ki, the selection of which is determined by the size of Tr(Td(x))mod N = Td(Tr(x))mod N, and the specific value selection rules are shared secrets among participants, overcoming the shortcomings of previous schemes. In the key generation and encryption/decryption stages, more complex intermediate processes are used to achieve higher algorithm complexity, making the algorithm more robust against ordinary attacks. The algorithm is also compared with other RSA-based algorithms to demonstrate its effectiveness in terms of performance and security