A perda de grupos funcionais em comunidades virtuais: efeito das interações entre espécies e grupos funcionais

High levels of local, regional, and global extinctions has progressively simplified communities in terms of both species and ecosystem functioning. Theoretical models demonstrated that the degree of functional redundancy determines the rates of functional group loss in response to species extinctions. Here, we improve the theoretical predictions by incorporating in the model interactions between species and between functional groups. In this study, we tested the effect of different scenarios of interspecific interactions and effects between functional groups on the resistance to loss of community functional groups. Virtual communities have been built with different distribution patterns of species in functional groups, both with high and low evenness. A matrix A was created to represent the net effect of interspecific interactions among all species, representing nesting patterns, modularity, sensitive species, and dominant species. Moreover, a second matrix B was created to represent the interactions between functional groups, also exhibiting different patterns. The extinction probability of each species was calculated based on community species richness and by the intensity of the interspecific interactions that act upon it and group to which it belongs. In the model, successive extinctions decrease the community species richness, the degree of functional redundancy and, consequently, the number of functional groups that remain in the system. For each scenario of functional redundancy, A, and B, we ran 1000 simulations to generate an average functional extinction curve. Different model assumptions were able to generate remarkable variation on functional extinction curves. More extreme variations occurred when the matrix A and B caused a higher heterogeneity in the species extinction probability. Scenarios with sensitive species, positive or negative, showed a greater variation than the scenarios with dominant species. Nested interactions showed greater variation than scenarios where the interactions were in modules. Communities with maximal functional evenness can only be destabilized by the interactions between species and functional groups. In contrast, communities with low functional evenness can have its resistance either increased or decreased by the interactions. The concentration of positive interactions in low redundancy groups or negative interactions in high redundancy groups was able to decrease the functional extinction rates. In contrast, the concentration of negative interactions in low redundancy groups or positive interactions in high redundancy groups was able to increase the functional extinction rates. This model shows results that are relevant for species priorization in ecosystem conservation and restoration

Infra-estrutura para avaliação e testes de protocolos sociais de comunicação em ambientes tridimencionais compartilhados

The advent of the Internet stimulated the appearance of several services. An example is the communication ones present in the users day-by-day. Services as chat and e-mail reach an increasing number of users. This fact is turning the Net a powerful communication medium. The following work explores the use of communication conventional services into the Net infrastructure. We introduce the concept of communication social protocols applied to a shared virtual environment. We argue that communication tools have to be adapted to the Internet potentialities. To do that, we approach some theories of the Communication area and its applicability in a virtual environment context. We define multi-agent architecture to support the offer of these services, as well as, a software and hardware platform to support the accomplishment of experiments using Mixed Reality. Finally, we present the obtained results, experiments and products

Análise de desempenho de sistemas distribuídos de grande porte na plataforma Java

The lava Platform is increasing1y being adopted in the development of distributed sys¬tems with higb user demando This kind of application is more complex because it needs beyond attending the functional requirements, to fulfil1 the pre-established performance parameters. This work makes a study on the Java Vutual Machine (JVM), approaching its intemal aspects and exploring the garbage collection strategies existing in the literature and used by the NM. It also presents a set of tools that helps in the job of optimizing applications and others that help in the monitoring of applications in the production envi¬ronment. Doe to the great amount of technologies that aim to solve problems which are common to the application layer, it becomes difficult to choose the one with best time response and less memory usage. This work presents a brief introduction to each one of tbe possible technologies and realize comparative tests through a statistical analysis of the response time and garbage collection activity random variables. The obtained results supply engineers and managers with a subside to decide which technologies to use in large applications through the knowledge of how they behave in their environments and the amount of resources that they consume. The relation between the productivity of the technology and its performance is also considered ao important factor in this choice

Um sistema para simular o comportamento de bancos trifásicos de reguladores de tensão usados em sistemas de distribuição de energia elétrica

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Desenvolvimento e testes de software de um receptor de GPS para uso espacial

Spacecraft move with high speeds and suffer abrupt changes in acceleration. So, an onboard GPS receiver could calculate navigation solutions if the Doppler effect is taken into consideration during the satellite signals acquisition and tracking. Thus, for the receiver subject to such dynamic cope these shifts in the frequency signal, resulting from this effect, it is imperative to adjust its acquisition bandwidth and increase its tracking loop to a higher order. This paper presents the changes in the GPS Orion s software, an open architecture receiver produced by GEC Plessey Semiconductors, nowadays Zarlink, in order to make it able to generate navigation fix for vehicle under high dynamics, especially Low Earth Orbit satellites. GPS Architect development system, sold by the same company, supported the modifications. Furthermore, it presents GPS Monitor Aerospace s characteristics, a computational tool developed for monitoring navigation fix calculated by the GPS receiver, through graphics. Although it was not possible to simulate the software modifications implemented in the receiver in high dynamics, it was observed that the receiver worked in stationary tests, verified also in the new interface. This work also presents the results of GPS Receiver for Aerospace Applications experiment, achieved with the receiver s participation in a suborbital mission, Operation Maracati 2, in December 2010, using a digital second order carrier tracking loop. Despite an incident moments before the launch have hindered the effective navigation of the receiver, it was observed that the experiment worked properly, acquiring new satellites and tracking them during the VSB-30 rocket flight.

Redes neurais artificiais no ambiente de redes industriais foundation fieldbus usando blocos funcionais padrões

Industrial automation networks is in focus and is gradually replacing older architectures of systems used in automation world. Among existing automation networks, most prominent standard is the Foundation Fieldbus (FF). This particular standard was chosen for the development of this work thanks to its complete application layer specification and its user interface, organized as function blocks and that allows interoperability among different vendors' devices. Nowadays, one of most seeked solutions on industrial automation are the indirect measurements, that consist in infering a value from measures of other sensors. This can be made through implementation of the so-called software sensors. One of the most used tools in this project and in sensor implementation are artificial neural networks. The absence of a standard solution to implement neural networks in FF environment makes impossible the development of a field-indirect-measurement project, besides other projects involving neural networks, unless a closed proprietary solution is used, which dos not guarantee interoperability among network devices, specially if those are from different vendors. In order to keep the interoperability, this work's goal is develop a solution that implements artificial neural networks in Foundation Fieldbus industrial network environment, based on standard function blocks. Along the work, some results of the solution's implementation are also presented

Estratégia de escalonamento de controladores PID baseado em regras Fuzzy para redes industriais foundation fieldbus usando blocos padrões

The main objective of work is to show procedures to implement intelligent control strategies. This strategies are based on fuzzy scheduling of PID controllers, by using only standard function blocks of this technology. Then, the standardization of Foundation Fieldbus is kept. It was developed an environment to do the necessary tests, it validates the propose. This environment is hybrid, it has a real module (the fieldbus) and a simulated module (the process), although the control signals and measurement are real. Then, it is possible to develop controllers projects. In this work, a fuzzy supervisor was developed to schedule a network of PID controller for a non-linear plant. Analyzing its performance results to the control and regulation problem

Sistema inteligente para detecção de manchas de óleo na superfície marinha através de imagens de SAR

Oil spill on the sea, accidental or not, generates enormous negative consequences for the affected area. The damages are ambient and economic, mainly with the proximity of these spots of preservation areas and/or coastal zones. The development of automatic techniques for identification of oil spots on the sea surface, captured through Radar images, assist in a complete monitoring of the oceans and seas. However spots of different origins can be visualized in this type of imaging, which is a very difficult task. The system proposed in this work, based on techniques of digital image processing and artificial neural network, has the objective to identify the analyzed spot and to discern between oil and other generating phenomena of spot. Tests in functional blocks that compose the proposed system allow the implementation of different algorithms, as well as its detailed and prompt analysis. The algorithms of digital image processing (speckle filtering and gradient), as well as classifier algorithms (Multilayer Perceptron, Radial Basis Function, Support Vector Machine and Committe Machine) are presented and commented.The final performance of the system, with different kind of classifiers, is presented by ROC curve. The true positive rates are considered agreed with the literature about oil slick detection through SAR images presents

Acelaração do universo e criação gravitacional de matéria escura fria: novos modelos e testes observacionais

Recent astronomical observations (involving supernovae type Ia, cosmic background radiation anisotropy and galaxy clusters probes) have provided strong evidence that the observed universe is described by an accelerating, flat model whose space-time properties can be represented by the FriedmannRobertsonWalker (FRW) metric. However, the nature of the substance or mechanism behind the current cosmic acceleration remains unknown and its determination constitutes a challenging problem for modern cosmology. In the general relativistic description, an accelerat ing regime is usually obtained by assuming the existence of an exotic energy component endowed with negative pressure, called dark energy, which is usually represented by a cosmological constant ¤ associated to the vacuum energy density. All observational data available so far are in good agreement with the concordance cosmic ¤CDM model. Nevertheless, such models are plagued with several problems thereby inspiring many authors to propose alternative candidates in the relativistic context. In this thesis, a new kind of accelerating flat model with no dark energy and fully dominated by cold dark matter (CDM) is proposed. The number of CDM particles is not conserved and the present accelerating stage is a consequence of the negative pressure describing the irreversible process of gravitational particle creation. In order to have a transition from a decelerating to an accelerating regime at low redshifts, the matter creation rate proposed here depends on 2 parameters (y and ߯): the first one identifies a constant term of the order of H0 and the second one describes a time variation proportional to he Hubble parameter H(t). In this scenario, H0 does not need to be small in order to solve the age problem and the transition happens even if there is no matter creation during the radiation and part of the matter dominated phase (when the ß term is negligible). Like in flat ACDM scenarios, the dimming of distant type Ia supernovae can be fitted with just one free parameter, and the coincidence problem plaguing the models driven by the cosmological constant. ACDM is absent. The limits endowed with with the existence of the quasar APM 08279+5255, located at z = 3:91 and with an estimated ages between 2 and 3 Gyr are also investigated. In the simplest case (ß = 0), the model is compatible with the existence of the quasar for y > 0:56 whether the age of the quasar is 2.0 Gyr. For 3 Gyr the limit derived is y > 0:72. New limits for the formation redshift of the quasar are also established

Testes cinemáticos em cosmologia com decaimento do vácuo

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Análise em conjunta de testes cosmológicos

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Efeitos imediatos da eletroestimulação nervosa transcutânea e crioterapia na espasticidade e na atividade eletromiográfica de sujeitos hemiparéticos

Cerebrovascular accident (CVA) is a term used to characterize an ischemic or hemorrhagic vascular injury, which has got as main clinic manifestations, the motor and reflex function disturbance. In the first stage there is flaccidity and loss of voluntary movements that afterwards is substituted by mass patterns and spasticity. The spasticity brings with itself functional deficits and can generate negative impacts in various motor patterns. The aim of this research was to investigate the hyperreflexia and identify the immediate effects of transcutaneous nervous stimulation (TENS) and cryotherapy in the spasticity and electromyographic activity of hemiparetic subjects. The study is characterized as an almost experimental type, in which were selected, to compose the sample, 16 patients of both sex with CVA sequel. These individuals were evaluated by collecting the amplitude peak to peak and H reflex latency, Motor response (M response) in solear muscle and the electromyography (EMG) of the injured and healthy legs anterior tibial muscles. In the injured limb the evaluations occurred in different days for cryotherapy, TENS and control, in two moments, before and after the interventions. The healthy limb was evaluated one single time to serve as baseline, for comparison with the injured limb. It was used an statistic analysis, the t paired student test to identify the H reflex differences, latency and EMG of the injured and healthy limbs and to compare the results before and after the recourses application. The ANOVA for related samples was used to identify the differences among the recourses used. It was attributed for the statistic tests a significance level of 5%. The amplitude peak to peak of normalized maximum H reflex through the maximum motor response (Hmax/Mmax), showed itself significantly increased in the injured limb (p=0.0245). The H reflex latency was presented reduced in the injured limb (p=0, 0375). The electromyographic activity was showed decreased in the injured limb (p< 0.0001). After the TENS there was a Hmáx/Mmáx ratio decrease (0.60±0.16 versus 0.49.±0.18; P = 0.0006). Nonetheless, Just after the cryotherapy application there was an increase of Hmáx/Mmáx ratio (0.58 ± 0,15 to 0.77 ± 0.13, P=0,0007) and increase of signal latency (30.41 ± 1.87 versus 33.24 ± 2.19; P=0.0001). The electromyographic activity wasn t altered significantly by any resource. It was met statistic significant differences when the Hmáx/Mmáx P<0.0001) ratio and H reflex latency (P<0.0001) were compared between the post TENS, cryotherapy and control. One can conclude that the TENS can be used to spasticity immediate reduction, and that the cryotherapy can increase the hyperreflexia state in spastic patients. Nonetheless, the spasticity decrease or increase didn t provoke lectromyographic activity change in the muscle that is opponent to the spastic one

Tradução, adaptação cultural e propriedades psicométricas da versão brasileira do Short-Form of the Mobility Assessment Tool (MAT-sf)

Objectives: to translate and assess the psychometric properties of the Brazilian short-form of the Mobility Assessment Tool (MAT-sf) in Brazilians community elderly. Methds: the 12 items MAT-sf went through the process of translation and back translation into Portuguese of the Brazil, considering the semantic and cultural adaptation. In a sample of 150 aged 65-74 years living in the community, the instrument's psychometric properties were evaluated by analysis of convergent and construct validity and test-retest reliability. The main outcomes measures used for validation included in the battery of tests of physical ability, self-repor measures of functional limitations, health, depression, cognitive and sex. The test-retest reliability of the instrument was assessed using the intra-class correlation coefficient (ICC), 40 subjects were reassessed after an interval of 14 days of assessment. Results: the concurrent validity for the MAT-sf was evidenced by significant correlations with SPPB (r = 0,53), number of functional limitations (r = -0,62) and depressive symptoms (r = -0,45). The construct validity of the instrument was measured by gradual and significant increase of the MAT-sf scores with high levels of physical performance and with positive self-reported health, also found that MAT-sf scores were statistically differents according to sex. The variation in MAT-sf scores (R2 = 0,41) was explained by SPPB, number of limitations for activities of daily life and depressive symptoms. High values for test-retest reliability was evidencend by ICC = 0,94, 95% CI = 0,90 0,97. Conclusions: the Brazilian version of the short-form of the Mobility Assessment Tool has values of validity and reliability to ensure its use in elderly populations living in communities

Associação entre polimorfismos funcionais nos genes da MMP-7 e MMP-9 e o perfil clinicopatológico do carcinoma epidermóide de língua

Matrix metalloproteinase-7 (MMP-7) and -9 (MMP-9) modulate important functions strictly related to the development, invasion and metastasis of several human cancers among them the squamous cell carcinoma of the tongue (SCCT). However, individual genetic factors such as the functional single nucleotide polymorphisms (SNPs) influence the pattern of protein expression of these MMPs and thus may be related to the variability observed in the clinical behavior of patients with SCCT. In this context, the present cross-sectional study aimed to evaluate the association between the frequency of the functional SNPs MMP-7 -181 A/G and MMP-9 -1562 C/T and the clinical (age, gender and metastasis) and pathological (malignancy histological grading and immunohistochemistry expression) features of SCCT cases. Genotyping of these SNPs were performed by PCR-RFLP on DNA samples from 71 cases of SCCT and 60 individuals without cancer who constitute the control group. Among the results of this research, it was observed that the frequency of the polymorphic alleles MMP-7 -181 G and MMP-9 -1562 T in SCCT patients was 28% and 12%, respectively, and the frequency of the heterozygotes A/G (PR = 2.00; p < 0.001) and C/T (PR = 1.54; p = 0.014) were significantly higher in the patient group than in the controls. The prevalence of patients carrying the combination of SNPs studied was significantly associated with SCCT cases (PR = 2.00; p = 0.011) and metastasis (PR = 2.00; p < 0.001). Furthermore, with the frequency of SNPs analyzed, the age, gender, histological grading and immunoreactivity of MMP-7 and MMP-9 formed clinical and pathological parameters relevant to the identification of population subgroups more related to the development of SCCT and metastasis. Based on these results, it is suggested that the protein expression levels of MMP-7 and -9 substantially influence the balance between their pro- and anticancer biological functions and hence the clinicopathological profile of the squamous cell carcinoma of the tongue

Diferenças funcionais das regiões hipocampais na formação da memória do tipo o quê", "quando" e "onde" em ratos

Episodic memory refers to the recollection of what, where and when a specific event occurred. Hippocampus is a key structure in this type of memory. Computational models suggest that the dentate gyrus (DG) and the CA3 hippocampal subregions are involved in pattern separation and the rapid acquisition of episodic memories, while CA1 is involved in memory consolidation. However there are few studies with animal models that access simultaneously the aspects ‗what-where-when . Recently, an object recognition episodic-like memory task in rodents was proposed. This task consists of two sample trials and a test phase. In sample trial one, the rat is exposed to four copies of an object. In sample trial two, one hour later, the rat is exposed to four copies of a different object. In the test phase, 1 h later, two copies of each of the objects previously used are presented. One copy of the object used in sample trial one is located in a different place, and therefore it is expected to be the most explored object.However, the short retention delay of the task narrows its applications. This study verifies if this task can be evoked after 24h and whether the pharmacological inactivation of the DG/CA3 and CA1 subregions could differentially impair the acquisition of the task described. Validation of the task with a longer interval (24h) was accomplished (animals showed spatiotemporal object discrimination and scopolamine (1 mg/kg, ip) injected pos-training impaired performance). Afterwards, the GABA agonist muscimol, (0,250 μg/μl; volume = 0,5 μl) or saline were injected in the hippocampal subregions fifteen minutes before training. Pre-training inactivation of the DG/CA3 subregions impaired the spatial discrimination of the objects (‗where ), while the temporal discrimination (‗when ) was preserved. Rats treated with muscimol in the CA1 subregion explored all the objects equally well, irrespective of place or presentation time. Our results corroborate the computational models that postulate a role for DG/CA3 in spatial pattern separation, and a role for CA1 in the consolidation process of different mnemonic episodes