A Survey of PAPR Techniques Based on Machine Learning.

Orthogonal Frequency Division Multiplexing (OFDM) is the modulation technology used in Fourth Generation (4G) and Fifth Generation (5G) wireless communication systems, and it will likely be essential to Sixth Generation (6G) wireless communication systems. However, OFDM introduces a high Peak to Average Power Ratio (PAPR) in the time domain due to constructive interference among multiple subcarriers, increasing the complexity and cost of the amplifiers and, consequently, the cost and complexity of 6G networks. Therefore, the development of new solutions to reduce the PAPR in OFDM systems is crucial to 6G networks. The application of Machine Learning (ML) has emerged as a promising avenue for tackling PAPR issues. Along this line, this paper presents a comprehensive review of PAPR optimization techniques with a focus on ML approaches. From this survey, it becomes clear that ML solutions offer customized optimization, effective search space navigation, and real-time adaptability. In light of the demands of evolving 6G networks, integration of ML is a necessity to propel advancements and meet increasing prerequisites. This integration not only presents possibilities for PAPR reduction but also calls for continued exploration to harness its potential and ensure efficient and reliable communication within 6G networks.

Dataset on productive functional traits at first lactation and productive longevity from a herd of 185 Montbéliarde and Holstein cows managed on a low-input mountain-area grassland farm.

The dataset available here comes from an experimental dairy cattle farm located in a mountain region in Central France, where the feeding systems are mostly pasture grazing combined with a period of indoor overwintering during the colder months. The dataset comprises individual productive and functional traits covering over 36 different variables in 185 primiparous Montbéliarde and Holstein cows, followed by data on productive longevity and reason for culling. The data was collected over a 20-year period during which animal husbandry and data collection protocols remained consistent. Potential re-users of the data are private-sector professionals, farmer associations, and researchers interested in developing statistical and mechanistic models and simulations of individual dairy cows under low-input grassland-based systems.

A Literature Survey on AI-Aided Beamforming and Beam Management for 5G and 6G Systems.

Modern wireless communication systems rely heavily on multiple antennas and their corresponding signal processing to achieve optimal performance. As 5G and 6G networks emerge, beamforming and beam management become increasingly complex due to factors such as user mobility, a higher number of antennas, and the adoption of elevated frequencies. Artificial intelligence, specifically machine learning, offers a valuable solution to mitigate this complexity and minimize the overhead associated with beam management and selection, all while maintaining system performance. Despite growing interest in AI-assisted beamforming, beam management, and selection, a comprehensive collection of datasets and benchmarks remains scarce. Furthermore, identifying the most-suitable algorithm for a given scenario remains an open question. This article aimed to provide an exhaustive survey of the subject, highlighting unresolved issues and potential directions for future developments. The discussion encompasses the architectural and signal processing aspects of contemporary beamforming, beam management, and selection. In addition, the article examines various communication challenges and their respective solutions, considering approaches such as centralized/decentralized, supervised/unsupervised, semi-supervised, active, federated, and reinforcement learning.

Emerging MIMO Technologies for 6G Networks.

The demand for wireless connectivity has grown exponentially over the last years. By 2030 there should be around 17 billion of mobile-connected devices, with monthly data traffic in the order of thousands of exabytes. Although the Fifth Generation (5G) communications systems present far more features than Fourth Generation (4G) systems, they will not be able to serve this growing demand and the requirements of innovative use cases. Therefore, Sixth Generation (6G) Networks are expected to support such massive connectivity and guarantee an increase in performance and quality of service for all users. To deal with such requirements, several technical issues need to be addressed, including novel multiple-antenna technologies. Then, this survey gives a concise review of the main emerging Multiple-Input Multiple-Output (MIMO) technologies for 6G Networks such as massive MIMO (mMIMO), extremely large MIMO (XL-MIMO), Intelligent Reflecting Surfaces (IRS), and Cell-Free mMIMO (CF-mMIMO). Moreover, we present a discussion on how some of the expected key performance indicators (KPIs) of some novel 6G Network use cases can be met with the development of each MIMO technology.

A Survey on the Impact of Intelligent Surfaces in the Terahertz Communication Channel Models.

Terahertz (THz) band will play an important role in enabling sixth generation (6G) envisioned applications. Compared with lower frequency signals, THz waves are severely attenuated by the atmosphere temperature, pressure, and humidity. Thus, designing a THz communication system must take into account how to circumvent or diminish those issues to achieve a sufficient quality of service. Different solutions are being analyzed: intelligent communication environments, ubiquitous artificial intelligence, extensive network automation, and dynamic spectrum access, among others. This survey focuses on the benefits of integrating intelligent surfaces (ISs) and THz communication systems by providing an overview of IS in wireless communications with the scanning of the recent developments, a description of the architecture, and an explanation of the operation. The survey also covers THz channel models, differentiating them based on deterministic and statistical channel modeling. The IS-aided THz channels are elucidated at the end of the survey. Finally, discussions and research directions are given to help enrich the IS field of research and guide the reader through open issues.

Análise do delay e perfil de acometimento de pacientes com infarto agudo do miocárdio admitidos em um Serviço de Cardiologia / Analysis of delay and involvement profile of acute myocardial infarction patients admitted to a Cardiology Service

Introdução: A doença cardíaca isquêmica é a principal causa de morbi/mortalidade no Brasil. O sucesso da terapêutica é inversamente proporcional ao tempo de admissão, diagnóstico e tratamento. Este trabalho teve como objetivo avaliar o tempo entre o início dos sintomas de um infarto agudo do miocárdio e a procura no atendimento médico, além do perfil dos pacientes. Métodos: Estudo observacional, retrospectivo, descritivo, com coleta de dados secundários e abordagem quantitativa. Resultados: Foram analisados 238 prontuários, 76,5%, homens e 23,5%, mulheres. A média de idade foi de 61,74 ± 11,45 anos, com maior acometimento entre 55-65 anos (35,3%). Os pacientes se apresentaram, em sua maioria, com delta T de 2 a 6 horas (47,3%), sendo que 20% das mulheres se apresentaram com um delta T >24h (vs 7,4% dos homens), e 34% das mulheres (vs 50,9%) apresentaram delta T entre 2 e 6h (p= 0,049). Dos pacientes com delta T <2h, 75% estavam a < 10km (p= 0,001). Nos pacientes com tempo <2h, a trombólise foi realizada em 10% e, nos casos com >12h, o tratamento de escolha foi o conservador, sem terapia de reperfusão específica (38,8%) (p=0,001). Conclusão: Os pacientes mais prevalentes foram homens com média de 63 anos. Distância menor que 10 km e o sexo masculino (nos tempos de apresentação maiores do que 2 horas) foram fatores de apresentação precoce. A idade não se associou a atraso no atendimento.

Introduction: Ischemic heart disease is the main cause of morbidity and mortality in Brazil. Therapeutic success is inversely proportional to time to admission, diagnosis, and treatment. This study aimed to evaluate the time from start of acute myocardial symptoms to search for medical care, in addition to investigate patients' profile. Methods: This is a quantitative, descriptive, observational, retrospective study of secondary data. Results: A total of 238 medical records were analyzed, of which 76.5% belonged to men and 23.5% to women. Mean age was 61.74 ± 11.45 years, and the most affected age group was 55-65 years (35.3%). Most patients had a delta T from 2 to 6 hours (47.3%), 20% of women had a delta T >24h (vs. 7.4% of men), and 34% of women (vs. 50.9%) had a delta T from 2 to 6 hours (p= 0.049). Of patients with a delta T <2h, 75% were < 10km distant from hospital care (p= 0,001). Thrombolysis was performed in 10% of patients with time of presentation <2h, and, in cases with time of presentation>12h, the treatment of choice was conservative, with no specific reperfusion therapy (38.8%) (p=0.001). Conclusion: There was a high prevalence of male patients with mean age of 63 years. Distance from hospital below 10 km and male sex (in times of presentation greater than 2 hours) were factors of early presentation. Age was not associated with delayed care.

Análise do delay e perfil de acometimento de pacientes com infarto agudo do miocárdio admitidos em um Serviço de Cardiologia / Analysis of delay and involvement profile of acute myocardial infarction patients admitted to a Cardiology Service

Introdução: A doença cardíaca isquêmica é a principal causa de morbi/mortalidade no Brasil. O sucesso da terapêutica é inversamente proporcional ao tempo de admissão, diagnóstico e tratamento. Este trabalho teve como objetivo avaliar o tempo entre o início dos sintomas de um infarto agudo do miocárdio e a procura no atendimento médico, além do perfil dos pacientes. Métodos: Estudo observacional, retrospectivo, descritivo, com coleta de dados secundários e abordagem quantitativa. Resultados: Foram analisados 238 prontuários, 76,5%, homens e 23,5%, mulheres. A média de idade foi de 61,74 ± 11,45 anos, com maior acometimento entre 55-65 anos (35,3%). Os pacientes se apresentaram, em sua maioria, com delta T de 2 a 6 horas (47,3%), sendo que 20% das mulheres se apresentaram com um delta T >24h (vs 7,4% dos homens), e 34% das mulheres (vs 50,9%) apresentaram delta T entre 2 e 6h (p= 0,049). Dos pacientes com delta T <2h, 75% estavam a < 10km (p= 0,001). Nos pacientes com tempo <2h, a trombólise foi realizada em 10% e, nos casos com >12h, o tratamento de escolha foi o conservador, sem terapia de reperfusão específica (38,8%) (p=0,001). Conclusão: Os pacientes mais prevalentes foram homens com média de 63 anos. Distância menor que 10 km e o sexo masculino (nos tempos de apresentação maiores do que 2 horas) foram fatores de apresentação precoce. A idade não se associou a atraso no atendimento.

Introduction: Ischemic heart disease is the main cause of morbidity and mortality in Brazil. Therapeutic success is inversely proportional to time to admission, diagnosis, and treatment. This study aimed to evaluate the time from start of acute myocardial symptoms to search for medical care, in addition to investigate patients' profile. Methods: This is a quantitative, descriptive, observational, retrospective study of secondary data. Results: A total of 238 medical records were analyzed, of which 76.5% belonged to men and 23.5% to women. Mean age was 61.74 ± 11.45 years, and the most affected age group was 55-65 years (35.3%). Most patients had a delta T from 2 to 6 hours (47.3%), 20% of women had a delta T >24h (vs. 7.4% of men), and 34% of women (vs. 50.9%) had a delta T from 2 to 6 hours (p= 0.049). Of patients with a delta T <2h, 75% were < 10km distant from hospital care (p= 0,001). Thrombolysis was performed in 10% of patients with time of presentation <2h, and, in cases with time of presentation >12h, the treatment of choice was conservative, with no specific reperfusion therapy (38.8%) (p=0.001). Conclusion: There was a high prevalence of male patients with mean age of 63 years. Distance from hospital below 10 km and male sex (in times of presentation greater than 2 hours) were factors of early presentation. Age was not associated with delayed care.

Deploying an NFV-Based Experimentation Scenario for 5G Solutions in Underserved Areas.

Presently, a significant part of the world population does not have Internet access. The fifth-generation cellular network technology evolution (5G) is focused on reducing latency, increasing the available bandwidth, and enhancing network performance. However, researchers and companies have not invested enough effort into the deployment of the Internet in remote/rural/undeveloped areas for different techno-economic reasons. This article presents the result of a collaboration between Brazil and the European Union, introducing the steps designed to create a fully operational experimentation scenario with the main purpose of integrating the different achievements of the H2020 5G-RANGE project so that they can be trialed together into a 5G networking use case. The scenario encompasses (i) a novel radio access network that targets a bandwidth of 100 Mb/s in a cell radius of 50 km, and (ii) a network of Small Unmanned Aerial Vehicles (SUAV). This set of SUAVs is NFV-enabled, on top of which Virtual Network Functions (VNF) can be automatically deployed to support occasional network communications beyond the boundaries of the 5G-RANGE radio cells. The whole deployment implies the use of a virtual private overlay network enabling the preliminary validation of the scenario components from their respective remote locations, and simplifying their subsequent integration into a single local demonstrator, the configuration of the required GRE/IPSec tunnels, the integration of the new 5G-RANGE physical, MAC and network layer components and the overall validation with voice and data services.

Comparative analysis of hydraulic refrigeration and mechanical vapour compression water cooling technologies in designing a technical system for oysters conservation.

The phenomenon of summer mortality in Pacific oysters cultures also occurs in Brazilian crops, with predominance in the adult phase, generating significant losses for local producers. In the search for a technological solution to mitigate its effects, the mechanical vapour compression and hydraulic refrigeration concepts are evaluated as two proposed cooling technologies. The comparative analysis carried out with numeric simulations indicated that the hydraulic cooling system presents disadvantages regarding both the size of the compression column and the energy efficiency, compared to the mechanical vapour compression cycle. By computing only the compression power, a COP value of 6.9 results for the MVCS at TCOND = 29.5 oC and TEVAP = 7.2 oC, while for HRS the COP value is around 3.1 for identical conditions. Results from the analysis contradict former publications, but are consistent with recent findings reported in literature.

Multiband 5G NR system with photonic-assisted RF amplification.

We propose and report the implementation of a multiband and photonically amplified fifth-generation (5G) new radio (NR) system based on radio over fiber technology and four-wave mixing (FWM) nonlinear effect. A piece of highly nonlinear fiber has been employed to stimulate FWM, which enables photonics-assisted RF amplification up to millimeter waves. Experimental results demonstrate a uniform and stable 15 dB ultra-wideband gain for 4G and three 5G signals in the frequency range from 780 MHz to 26 GHz, coexisting in the transport network. The obtained digital performance has efficiently met the Third-Generation Partnership Project requirements, demonstrating the applicability of the proposed approach for using fiber-optic links to distribute and jointly amplify 4G and 5G signals in the optical domain.

Health and Safety at Work: Analysis from the Brazilian Documentary Film Flesh and Bone.

BACKGROUND: The objective of this article is to make some analysis on the process of work and accidents occurring in slaughterhouses, evidenced in the Brazilian documentary film called Flesh and Bone. As such, it was necessary to discuss an alternative theoretical concept in relation to theories about health and safety at work. This alternative discussion focuses on the concepts of biopower and biopolitics. METHODS: The use of audiovisual elements in research is not new, and there is already a branch of studies with methodological and epistemological variations. The Brazilian documentary Flesh and Bone was the basis for the research. The analysis of this documentary will be carried out from two complementary perspectives: "textual analysis" and "discourse analysis." RESULTS: Flesh and Bone presents problems related to health and safety at work in slaughterhouses because of the constant exposure of workers to knives, saws, and other sharp instruments in the workplace. The results show that in favor of higher production levels, increased overseas market sales, and stricter quality controls, some manufacturers resort to various practices that often result in serious injuries, disposal, and health damages to workers. CONCLUSION: Flesh and Bone, by itself, makes this explicit in the form of denunciation based on the situation of these workers. What it does not make clear is that, in the context of biopolitics, the actions aimed at solving these problems or even reducing the negative impacts for this group of workers, are not efficient enough to change such practices.

Combined Pre-Distortion and Censoring for Bandwidth-Efficient and Energy-Efficient Fusion of Spectrum Sensing Information.

This paper describes a novel scheme for the fusion of spectrum sensing information in cooperative spectrum sensing for cognitive radio applications. The scheme combines a spectrum-efficient, pre-distortion-based fusion strategy with an energy-efficient censoring-based fusion strategy to achieve the combined effect of reduction in bandwidth and power consumption during the transmissions of the local decisions to the fusion center. Expressions for computing the key performance metrics of the spectrum sensing of the proposed scheme are derived and validated by means of computer simulations. An extensive analysis of the overall energy efficiency is made, along with comparisons with reference strategies proposed in the literature. It is demonstrated that the proposed fusion scheme can outperform the energy efficiency attained by these reference strategies. Moreover, it attains approximately the same global decision performance of the best among these strategies.

Reduction of ammonia emissions from dairy cattle cubicle houses via improved management- or design-based strategies: A modeling approach.

Given the current scarcity of empirical data on ammonia (NH3) emissions from dairy cattle under different management-based mitigation techniques, a modeling approach to assess potential NH3 emission reduction factors is needed. This paper introduces a process-based model that estimates NH3 emission reduction factors for a dairy cattle barn featuring single or multiple management-based NH3 emission mitigation techniques, as compared to another barn, to which no mitigation measure is applied. The model accounts for the following emission mitigation measures: (a) floor scraping, (b) floor type, (c) floor flushing with water and (d) indoor acidification of manure. Model sensitivity analysis indicated that manure acidification was the most efficient NH3 emission reduction technique. A fair agreement was observed between reduction factors from the model and empirical estimates found in the literature. We propose a list of combinations of techniques that achieve the largest reductions. In order of efficiency, they are: (a) floor scraping combined with manure acidification (reduction efficiency 44-49%); (b) solid floor combined with scraping and flushing (reduction efficiency 21-27%); (c) floor scraping combined with flushing and (d) floor scraping alone (reduction efficiency 17-22%). The model is currently being used to advise the Flemish Government (Belgium), on the performance of certain NH3 emission reduction systems for dairy barns in Flanders.

Wind tunnel study of ammonia transfer from a manure pit fitted with a dairy cattle slatted floor.

In dairy cattle systems, most of the feces and urine go to the pit. At the manure pit level, mass transfer of NH3 ([Formula: see text]) has many factors, but practical difficulties hamper a controlled field evaluation. In this study, we propose a methodology for the determination of an alternative, more practical, pit transfer coefficient of NH3 (PTC), and compare it with [Formula: see text] determined from other scientific studies. The aims of this research study were: (1) to develop a wind tunnel set-up which mimics air flow patterns between the slats and above a clean section of a slatted floor section, featuring an aqueous NH3-emitting solution; and (2) to assess how air velocity, turbulence intensity, NH3 concentration ([NH3]) and PTC are influenced by inlet airflow ventilation rate (VR) forced deflection of the air above the slats into the manure pit through varying the deflection angle (DA) of a deflection panel and varying pit headspace height (HH). Main conclusions were: (1) the calculated PTC values presented a good fit to the power function of the air speed near the slats (u) (p < .001) while the average PTC (0.0039 m s(-1)) was comparable to [Formula: see text] values obtained from other studies, by remaining within the range of average values of 0.0015-0.0043 m s(-1); (2) VR and DA significantly impacted [NH3] profiles and PTC (p < .001) and (3) changing slurry pit from 0.10 to 0.90 m HH did not significantly impact [NH3] or PTC (p = .756 and p = .854, respectively).

NDIR Gas Sensor for Spatial Monitoring of Carbon Dioxide Concentrations in Naturally Ventilated Livestock Buildings.

The tracer gas ratio method, using CO2 as natural tracer, has been suggested as a pragmatic option to measure emissions from naturally ventilated (NV) barns without the need to directly estimate the ventilation rate. The aim of this research was to assess the performance of a low-cost Non-Dispersive Infra-Red (NDIR) sensor for intensive spatial field monitoring of CO2 concentrations in a NV dairy cow house. This was achieved by comparing NDIR sensors with two commonly applied methods, a Photo-Acoustic Spectroscope (PAS) Gas Monitor and an Open-Path laser (OP-laser). First, calibrations for the NDIR sensors were obtained in the laboratory. Then, the NDIR sensors were placed in a dairy cow barn for comparison with the PAS and OP-laser methods. The main conclusions were: (a) in order to represent the overall barn CO2 concentration of the dairy cow barn, the number of NDIR sensors to be accounted for average concentration calculation was dependent on barn length and on barn area occupation; and (b) the NDIR CO2 sensors are suitable for multi-point monitoring of CO2 concentrations in NV livestock barns, being a feasible alternative for the PAS and the OP-laser methods to monitor single-point or averaged spatial CO2 concentrations in livestock barns.

Os sentidos e significados no trabalho de controlador de tráfego aéreo / The senses and meanings in the work of air traffic controller

O objetivo neste artigo foi compreender os sentidos e significados no trabalho de controlador de tráfego aéreo, elucidando sua importância para a segurança da população brasileira e considerando o destaque que a profissão recebeu na mídia a partir do problema do "apagão aéreo" no Brasil. Para tanto, de início, houve a necessidade de aprofundar algumas discussões teóricas sobre sentidos e significados do trabalho, com a intenção de entender aspectos relativos a esses conceitos. Após essas considerações teóricas, foi elucidado o percurso metodológico, destacando a modalidade de pesquisa, a maneira como foi executada, os sujeitos e o método de análise dos dados. Com esse percurso, foi possível, no tópico seguinte, entender os sentidos e significados do trabalho para os controladores entrevistados. Como conclusão, ficou evidente que, na profissão de controlador de tráfego aéreo, há, por exemplo, compatibilidade entre os anseios dos profissionais e as exigências da função.(AU)

The objective in this paper was to understand the senses and meanings in the work of air traffic controller, explaining its importance to the safety of the population and considering the emphasis that the profession has received in the media on the "air blackout" problem in Brazil. Therefore, initially, there was a need for some further theoretical discussions on senses and meanings of the work, with the intention to understand aspects relative to these concepts. After these theoretical considerations, methodological approach was elucidated, highlighting the research mode, the way it was performed, the subject and the method of data analysis. With this route, it was possible, in the next section, to understand the senses and meanings of work for the controllers interviewed. In conclusion, it was evident that, in the profession of air traffic controller, there are, for example, the compatibility between the aspirations of professionals and job requirements.(AU)

Os sentidos e significados no trabalho de controlador de tráfego aéreo / The senses and meanings in the work of air traffic controller

O objetivo neste artigo foi compreender os sentidos e significados no trabalho de controlador de tráfego aéreo, elucidando sua importância para a segurança da população brasileira e considerando o destaque que a profissão recebeu na mídia a partir do problema do "apagão aéreo" no Brasil. Para tanto, de início, houve a necessidade de aprofundar algumas discussões teóricas sobre sentidos e significados do trabalho, com a intenção de entender aspectos relativos a esses conceitos. Após essas considerações teóricas, foi elucidado o percurso metodológico, destacando a modalidade de pesquisa, a maneira como foi executada, os sujeitos e o método de análise dos dados. Com esse percurso, foi possível, no tópico seguinte, entender os sentidos e significados do trabalho para os controladores entrevistados. Como conclusão, ficou evidente que, na profissão de controlador de tráfego aéreo, há, por exemplo, compatibilidade entre os anseios dos profissionais e as exigências da função.

The objective in this paper was to understand the senses and meanings in the work of air traffic controller, explaining its importance to the safety of the population and considering the emphasis that the profession has received in the media on the "air blackout" problem in Brazil. Therefore, initially, there was a need for some further theoretical discussions on senses and meanings of the work, with the intention to understand aspects relative to these concepts. After these theoretical considerations, methodological approach was elucidated, highlighting the research mode, the way it was performed, the subject and the method of data analysis. With this route, it was possible, in the next section, to understand the senses and meanings of work for the controllers interviewed. In conclusion, it was evident that, in the profession of air traffic controller, there are, for example, the compatibility between the aspirations of professionals and job requirements.

Glow-to-arc transition events in H2-Ar direct current pulsed plasma: automated measurement of current and voltage.

The glow-to-arc transition phenomena (arcing) observed in plasma reactors used in materials processing was studied through the arcs characteristic current and voltage waveforms. In order to capture these arcs signals, a LABVIEW™ based automated instrumentation system (ARCVIEW) was developed, including the integration of an oscilloscope equipped with proper current and voltage probes. The system also allows capturing the process parameters at the arc occurrence moments, which were used to map the arcs events conditions. Experiments in H(2)-Ar DC pulsed plasma returned signals data from 215 arcs events, which were analyzed through software routines. According to the results, an anti-arcing system should react in the time order of few microseconds to prevent most of the damage caused by the undesired arcing phenomena.

[Influence of reproductive factors in the clinical and laboratory parameters of rheumatoid arthritis]. / Influência de fatores reprodutivos sobre parâmetros clínicos e laboratoriais da artrite reumatoide.

PURPOSE: To study if rheumatoid arthritis (RA) is influenced by age at menarche, number of pregnancies and reproductive life span. METHODS: This was a cross-sectional and retrospective study of medical records of 247 RA patients. We collected data on menarche, menopause, number of pregnancies, autoantibodies, serositis, rheumatoid nodules, and functional index of Steinbrocker. Association studies were done using the Student t and Mann-Whitney tests and correlation was determined by the Pearsonand Spearman tests. The level of significance adopted was 5%. RESULTS: The mean age at diagnosis of RA was 43.2±14.1 years, the median age at menarche was 13 years and the median number of pregnancies was 3. Rheumatoid factor was present in 63.9% of the patients, 20% had antinuclear factor, 8.8% rheumatoid nodules, 2.8% had pleural effusion, and 2.4% had pericarditis. The Steinbrocker functional index showed that 45.6% had a score of 1, 40.8% a score of 2, 3 score of 9.1, and 4.3% a score of 4. We found an inverse correlation between the number of pregnancies and age at onset of RA (p CONCLUSION: A precocious menarche and brief reproductive life indicate a poor prognosis regarding pleurisy. A larger number of pregnancies and late menopause show a protective effect, delaying the onset of the disease.

Influência de fatores reprodutivos sobre parâmetros clínicos e laboratoriais da artrite reumatoide / Influence of reproductive factors in the clinical and laboratory parameters of rheumatoid arthritis

OBJETIVO: Estudar se a artrite reumatoide (AR) sofre influências de idade de menarca, número de gestações e tempo de vida reprodutiva. MÉTODOS: Estudo transversal e retrospectivo dos prontuários de 247 pacientes com AR, cujos dados sobre menarca, menopausa, número de gestações, autoanticorpos, serosites, nódulos reumatoides e índice funcional de Steinbrocker foram coletados. Os estudos de associação foram feitos pelos testes t de Student e Mann Whitney; os de correlação, pelos testes de Pearson e de Spearman. A significância adotada foi de 5 por cento. RESULTADOS: A idade média de diagnóstico da AR foi de 43,2±14,1 anos, a idade mediana da menarca de 13 anos e o número mediano de gestações foi de 3. Em 63,9 por cento existia fator reumatoide; o fator antinuclear em 20 por cento; os nódulos reumatoides em 8,8 por cento; derrame pleural em 2,8 por cento e pericardite em 2,4 por cento. O índice funcional de Steinbrocker mostrou que 45,6 por cento tinham escore 1; 40,8 por cento o escore 2; 9,1 por cento o escore 3 e 4,3 por cento o escore 4. Encontrou-se correlação inversa entre a quantidade de gestações e idade de surgimento da AR (p CONCLUSÃO: A precocidade da menarca e brevidade da vida reprodutiva indicam pior prognóstico, já que se relacionam com pleurites. A maior quantidade de gestações e menopausa tardia mostram efeito protetor, retardando o aparecimento da doença.

PURPOSE: To study if rheumatoid arthritis (RA) is influenced by age at menarche, number of pregnancies and reproductive life span. METHODS: This was a cross-sectional and retrospective study of medical records of 247 RA patients. We collected data on menarche, menopause, number of pregnancies, autoantibodies, serositis, rheumatoid nodules, and functional index of Steinbrocker. Association studies were done using the Student t and Mann-Whitney tests and correlation was determined by the Pearsonand Spearman tests. The level of significance adopted was 5 percent. RESULTS: The mean age at diagnosis of RA was 43.2±14.1 years, the median age at menarche was 13 years and the median number of pregnancies was 3. Rheumatoid factor was present in 63.9 percent of the patients, 20 percent had antinuclear factor, 8.8 percent rheumatoid nodules, 2.8 percent had pleural effusion, and 2.4 percent had pericarditis. The Steinbrocker functional index showed that 45.6 percent had a score of 1, 40.8 percent a score of 2, 3 score of 9.1, and 4.3 percent a score of 4. We found an inverse correlation between the number of pregnancies and age at onset of RA (p CONCLUSION: A precocious menarche and brief reproductive life indicate a poor prognosis regarding pleurisy. A larger number of pregnancies and late menopause show a protective effect, delaying the onset of the disease.