A non-expensive bidimensional kinematic balance assessment can detect early postural instability in people with Parkinson's disease.

Background: Postural instability is a debilitating cardinal symptom of Parkinson's disease (PD). Its onset marks a pivotal milestone in PD when balance impairment results in disability in many activities of daily living. Early detection of postural instability by non-expensive tools that can be widely used in clinical practice is a key factor in the prevention of falls in widespread population and their negative consequences. Objective: This study aimed to investigate the effectiveness of a two-dimensional balance assessment to identify the decline in postural control associated with PD progression. Methods: This study recruited 55 people with PD, of which 37 were men. Eleven participants were in stage I, twenty-three in stage II, and twenty-one in stage III. According to the Hoehn and Yahr (H&Y) rating scale, three clinical balance tests (Timed Up and Go test, Balance Evaluation Systems Test, and Push and Release test) were carried out in addition to a static stance test recorded by a two-dimensional movement analysis software. Based on kinematic variables generated by the software, a Postural Instability Index (PII) was created, allowing a comparison between its results and those obtained by clinical tests. Results: There were differences between sociodemographic variables directly related to PD evolution. Although all tests were correlated with H&Y stages, only the PII was able to differentiate the first three stages of disease evolution (H&Y I and II: p = 0.03; H&Y I and III: p = 0.00001; H&Y II and III: p = 0.02). Other clinical tests were able to differentiate only people in the moderate PD stage (H&Y III). Conclusion: Based on the PII index, it was possible to differentiate the postural control decline among the first three stages of PD evolution. This study offers a promising possibility of a low-cost, early identification of subtle changes in postural control in people with PD in clinical practice.

Comparison of disability level between Early and Late Onset Parkinson's Disease using WHODAS 2.

Background: Parkinson's disease (PD) is a degenerative neurological disorder that usually affects people over the age of 60. However, 10%-20% of patients have an early onset of PD (EOPD). Objectives: To compare disability levels according to the World Health Organization Disability Assessment Schedule 2.0 (WHODAS-2) between people with EOPD and those with late-onset PD (LOPD). Methods: We conducted a cross-sectional study with 95 EOPD patients (mean-age 44.51 ± 4.63, H&Y 1.93 ± 0.93) and 255 LOPD patients (mean-age 63.01 ± 7.99, H&Y 2.02 ± 0.95). Demographic information, clinical characteristics, cognitive evaluation by Telephone-Montreal-Cognitive-Assessment (T-MoCA), functionality self-evaluation by WHODAS-2 and the Unified-Parkinson's-Disease-Rating-Scale (MDS-UPDRS), parts I and II, were documented for each patient by an individual remote interview. Results: Analysis showed a statistically significant difference between EOPD and LOPD in two domains of WHODAS-2 only: cognition (Z-adjusted = 2.60; p-value adjusted <0.009) and activities of daily living related to work/school (Z-adjusted = 2.34; p-value adjusted <0.01). T-MoCA scores confirmed more impaired cognition capacity in LOPD (Z-adjusted = 2.42; p-value adjusted <0.01). The two groups had no significant differences in levodopa daily dosage, Hoehn and Yahr (H&Y) stages, disease time duration, and MDS-UPDRS I and II scores. Conclusion: People living with EOPD face similar disability levels as those with LOPD, except for cognition, where LOPD patients exhibited higher levels of disability than EOPD and for work activities where the EOPD exhibited higher levels of disability than LODP. These results highlight the challenges faced by people with EOPD in interacting with society and living with the disease for a longer time. The WHODAS-2 can be a useful tool to assess disability and tailor interventions for people with PD of different age groups.

A non-expensive bidimensional assessment can detect subtle alterations in gait performance in people in the early stages of Parkinson's disease.

Background: Gait is one of the activities most affected by the symptoms of Parkinson's disease and may show a linear decline as the disease progresses. Early assessment of its performance through clinically relevant tests is a key factor in designing efficient therapeutic plans and procedures, which can be enhanced using simple and low-cost technological instruments. Objective: To investigate the effectiveness of a two-dimensional gait assessment to identify the decline in gait performance associated with Parkinson's disease progression. Methods: One hundred and seventeen people with Parkinson's disease, classified between early and intermediate stages, performed three clinical gait tests (Timed Up and Go, Dynamic Gait Index, and item 29 of the Unified Parkinson's Disease Rating Scale), in addition to a six-meter gait test recorded by a two-dimensional movement analysis software. Based on variables generated by the software, a gait performance index was created, allowing a comparison between its results with the results obtained by clinical tests. Results: There were differences between sociodemographic variables directly related to the evolution of Parkinson's disease. Compared to clinical tests, the index proposed to analyze gait showed greater sensitivity and was able to differentiate the first three stages of disease evolution (Hoehn and Yahr I and II: p = 0.03; Hoehn and Yahr I and III: p = 0.00001; Hoehn and Yahr II and III: p = 0.02). Conclusion: Based on the index provided by a two-dimensional movement analysis software that uses kinematic gait variables, it was possible to differentiate the gait performance decline among the three first stages of Parkinson's disease evolution. This study offers a promising possibility of early identification of subtle changes in an essential function of people with Parkinson's disease.

Leaf-cutting ants' critical and voluntary thermal limits show complex responses to size, heating rates, hydration level, and humidity.

Thermal variation has complex effects on organisms and they respond to these effects through combined behavioral and physiological mechanisms. However, it is less clear how these traits combine in response to changes in body condition (e.g., size, hydration) and environmental factors that surround the heating process (e.g., relative humidity, start temperatures, heating rates). We tested whether these body conditions and environmental factors influence sequentially measured Voluntary Thermal Maxima (VTmax) and Critical Thermal Maxima, (CTmax) in leaf-cutting ants (Atta sexdens rubropilosa, Forel, 1908). VTmax and CTmax reacted differently to changes in body size and relative humidity, but exhibited similar responses to hydration level, start temperature, and heating rate. Strikingly, the VTmax of average-sized workers was closer to their CTmax than the VTmax of their smaller and bigger sisters, suggesting foragers maintain normal behavior at higher temperatures than sister ants that usually perform tasks within the colony. Previous experiments based on hot plate designs might overestimate ants' CTmax. VTmax and CTmax may respond concomitantly or not to temperature rises, depending on body condition and environmental factors.

Seasonal variation in fatigue indicators in Brazilian civil aviation crew rosters.

BACKGROUND: Analyzing, understanding and managing fatigue risk in aviation is relevant for flight safety and to reduce human error. OBJECTIVE: To analyze probable levels of fatigue among a convenience sample of Brazilian civil aviation pilots and flight attendants and to develop appropriate methods and indicators to quantify potential fatigue risk in critical phases of flight (landings and takeoffs). METHODS: Data were obtained from flight rosters voluntarily and anonymously fed to a digital platform. Rosters were analyzed with software SAFTE-FAST, which considers homeostatic process and circadian cycles related to attention and wakefulness and sleep inertia. RESULTS: The rosters for January (n=248), May (n=259) and July (n=261) 2018 were associated with incidence of 77, 54 and 77% respectively of least one event of minimal effectiveness (<77%) during critical phases of flight. The distribution of minimal effectiveness and hazard area during critical phases of flight exhibited significant seasonal oscillation upon comparing the results for January and July relative to May 2018 (p<0.001). CONCLUSION: Relative likelihood of fatigue was high in the crew rosters, with significant seasonal oscillation of minimal effectiveness and hazard area in critical phases of flight. These results point to the need for improved roster management since prescriptive rules were insufficient to mitigate risk.

INTRODUÇÃO: Métodos de análise, compreensão e gerenciamento do risco da fadiga na aviação representam tópicos de interesse para a segurança de voo e mitigação de falhas humanas. OBJETIVO: Avaliar o provável nível de fadiga em uma amostra de conveniência de pilotos e comissários de voo da aviação regular brasileira, propondo metodologia e indicadores apropriados para a quantificação da potencial exposição ao risco da fadiga durante as fases críticas de voo (pousos e decolagens). MÉTODOS: Os dados foram obtidos por envio espontâneo e anônimo das escalas de voo para uma plataforma, sendo estas analisadas com o software Sleep, Activity, Fatigue, and Task Effectiveness / Fatigue Avoidance Scheduling Tool (SAFTE-FAST), que leva em conta o processo homeostático, os ritmos circadianos associados à atenção e vigília e a inércia do sono. RESULTADOS: As escalas dos meses de janeiro (n=248), maio (n=259) e julho (n=261) de 2018 tiveram incidência de 77, 54 e 77% de ao menos um evento com efetividade mínima nas fases críticas abaixo de 77%, respectivamente. As distribuições de efetividades mínimas e áreas de risco nas fases críticas apresentaram oscilação sazonal significativa, comparando os meses de janeiro ou julho com maio de 2018 (p<0,001). CONCLUSÕES: O estudo apontou probabilidade relativa elevada de fadiga nas escalas dos aeronautas, assim como oscilações sazonais significativas nas distribuições de efetividade mínima e aérea de risco nas fases críticas. Esses resultados indicam a necessidade de um melhor gerenciamento das escalas, visto que os limites prescritivos vigentes à época não foram suficientes para a mitigação dos riscos.

Sazonalidade de indicadores de fadiga nas escalas de trabalho dos aeronautas da aviação regular brasileira / Seasonal variation in fatigue indicators in Brazilian civil aviation crew rosters

Introdução: Métodos de análise, compreensão e gerenciamento do risco da fadiga na aviação representam tópicos de interesse para a segurança de voo e mitigação de falhas humanas. Objetivo: Avaliar o provável nível de fadiga em uma amostra de conveniência de pilotos e comissários de voo da aviação regular brasileira, propondo metodologia e indicadores apropriados para a quantificação da potencial exposição ao risco da fadiga durante as fases críticas de voo (pousos e decolagens). Métodos: Os dados foram obtidos por envio espontâneo e anônimo das escalas de voo para uma plataforma, sendo estas analisadas com o software Sleep, Activity, Fatigue, and Task Effectiveness / Fatigue Avoidance Scheduling Tool (SAFTE-FAST), que leva em conta o processo homeostático, os ritmos circadianos associados à atenção e vigília e a inércia do sono. Resultados: As escalas dos meses de janeiro (n=248), maio (n=259) e julho (n=261) de 2018 tiveram incidência de 77, 54 e 77% de ao menos um evento com efetividade mínima nas fases críticas abaixo de 77%, respectivamente. As distribuições de efetividades mínimas e áreas de risco nas fases críticas apresentaram oscilação sazonal significativa, comparando os meses de janeiro ou julho com maio de 2018 (p<0,001). Conclusões: O estudo apontou probabilidade relativa elevada de fadiga nas escalas dos aeronautas, assim como oscilações sazonais significativas nas distribuições de efetividade mínima e aérea de risco nas fases críticas. Esses resultados indicam a necessidade de um melhor gerenciamento das escalas, visto que os limites prescritivos vigentes à época não foram suficientes para a mitigação dos riscos.

Background: Analyzing, understanding and managing fatigue risk in aviation is relevant for flight safety and to reduce human error. Objective: To analyze probable levels of fatigue among a convenience sample of Brazilian civil aviation pilots and flight attendants and to develop appropriate methods and indicators to quantify potential fatigue risk in critical phases of flight (landings and takeoffs). Methods: Data were obtained from flight rosters voluntarily and anonymously fed to a digital platform. Rosters were analyzed with software SAFTEFAST, which considers homeostatic process and circadian cycles related to attention and wakefulness and sleep inertia. Results: The rosters for January (n=248), May (n=259) and July (n=261) 2018 were associated with incidence of 77, 54 and 77% respectively of least one event of minimal effectiveness (<77%) during critical phases of flight. The distribution of minimal effectiveness and hazard area during critical phases of flight exhibited significant seasonal oscillation upon comparing the results for January and July relative to May 2018 (p<0.001). Conclusion: Relative likelihood of fatigue was high in the crew rosters, with significant seasonal oscillation of minimal effectiveness and hazard area in critical phases of flight. These results point to the need for improved roster management since prescriptive rules were insufficient to mitigate risk.

Two castes sizes of leafcutter ants in task partitioning in foraging activity / Participação de dois tamanhos de castas de operárias de formigas cortadeiras no particionamento de tarefas da atividade de forrageamento

ABSTRACT: Task partitioning in eusocial animals is most likely an evolutionary adaptation that optimizes the efficiency of the colony to grow and reproduce. It was investigated indirect task partitioning in two castes sizes; this involves task partitioning in which the material transported is not transferred directly from one individual to another, but where it is dropped by one ant to be picked up by another. In two separate approaches, it was confirmed previous results pertaining to leaf caching activities among Atta colombica with task partitioning activities involving leaf dropping among Atta sexdens rubropilosa , in which there is a correlation between the size of an individual ant and the leaf fragment it transports. It was also suggested that this correlation exists only in individual ants that cut and transport (CaT) the same fragment to the nest. When task partitioning occurs and individual ants transporting (T) leaf fragments cut by other ants, the correlation becomes looser or disappears. We also observed that CaT ants are smaller than T ants.

RESUMO: Particionamento de tarefas em animais eusociais é provavelmente uma adaptação evolutiva, que otimiza a eficiência de forrageio da colônia, gerando maior capacidade de crescimento e reprodução. Nós investigamos o particionamento indireto de tarefas, com o envolvimento de castas de dois tamanhos distintos. Assim, o material coletado por uma formiga não era transportado diretamente ao ninho, nem transferido diretamente de um indivíduo para outro, mas sim descartado por uma formiga e coletado por outra. Em duas abordagens distintas, nós confirmamos em Atta sexdens rubropilosa resultados anteriores relativos à ocorrência deste particionamento indireto de tarefas, observado em Atta colombica . Mostramos também que, assim como em Atta colombica , há uma correlação entre os tamanhos da formiga e do fragmento de folha transportado quando esta corta e transporta este fragmento ao ninho (CaT). Mais ainda, confirmamos em Atta sexdens que, quando o particionamento de tarefas ocorre e as formigas apenas transportam o fragmento de folhas (T) cortadas por outras formigas, a correlação desaparece. Nós também descrevemos que as formigas CaT são menores do que as T.

Parkinson's disease progression: implicit acquisition, cognitive and motor impairments, and medication effects.

Parkinson's disease (PD) symptoms have been collectively ascribed to malfunctioning of dopamine-related nigro-striatal and cortico-striatal loops. However, some doubts about this proposition are raised by controversies about the temporal progression of the impairments, and whether they are concomitant or not. The present study consists of a systematic revision of literature data on both functional PD impairments and dopaminergic medication effects in order to draw a coherent picture about the disease progression. It was done in terms of an explanatory model for the disruption of implicit knowledge acquisition, motor and cognitive impairments, and the effects of dopaminergic medication on these functions. Cognitive impairments arise at early stages of PD and stabilizes while disruption of implicit knowledge acquisition and motor impairments, are still in progression; additionally, dopaminergic medication reduces motor impairments and increases disruption of implicit knowledge acquisition. Since this model revealed consistency and plausibility when confronted with data of others studies not included in model's formulation, it may turn out to be a useful tool for understanding the multifaceted characteristics of PD.

Ants can learn to forage on one-way trails.

The trails formed by many ant species between nest and food source are two-way roads on which outgoing and returning workers meet and touch each other all along. The way to get back home, after grasping a food load, is to take the same route on which they have arrived from the nest. In many species such trails are chemically marked by pheromones providing orientation cues for the ants to find their way. Other species rely on their vision and use landmarks as cues. We have developed a method to stop foraging ants from shuttling on two-way trails. The only way to forage is to take two separate roads, as they cannot go back on their steps after arriving at the food or at the nest. The condition qualifies as a problem because all their orientation cues -- chemical, visual or any other -- are disrupted, as all of them cannot but lead the ants back to the route on which they arrived. We have found that workers of the leaf-cutting ant Atta sexdens rubropilosa can solve the problem. They could not only find the alternative way, but also used the unidirectional traffic system to forage effectively. We suggest that their ability is an evolutionary consequence of the need to deal with environmental irregularities that cannot be negotiated by means of excessively stereotyped behavior, and that it is but an example of a widespread phenomenon. We also suggest that our method can be adapted to other species, invertebrate and vertebrate, in the study of orientation, memory, perception, learning and communication.

A construçäo da atençäo a partir da memória / Building attention from memory

Os processos que levam à seleçäo de certas categorias de informaçäo para processamento preferencial, que caracterizam a atençäo, dependem näo apenas da história prévia do sistema selecionador, isto é, suas memórias, como também de expectativas geradas com base em memórias sobre regularidades passadas e planos de açäo. Defende-se neste trabalho que a associaçäo conceitual envolvendo memória e atençäo é vantajosa pois permite oferecer explicaçöes parcimoniosas sobre diversos fenômeros revelados em estudos sobre atençäo, além de gerar previsöes testáveis sobre os efeitos da experiência prévia no desempenho em testes de atençäo. Apresenta-se aqui um modelo sobre a influência de memórias (representadas por vias facilitadas no sistema nervoso) na atividade da rede nervosa e nos processos atencionais durante o desempenho de determinados tipos de tarefas

[Building attention from memory]. / A construção da atenção a partir da memória.

The processes that lead to the selection of information for additional processing, which characterizes attention, depend upon previous experiences and expectancies generated in the light of stored past experiences regularities and plans for action. It is proposed that conceptual association between memory and attention brings advantages for explaining a diversity of attentional phenomena and allow to generate testable predictions relating past experiences and performance in tests for attention. A model is presented relating the trained neural network (memories) and attention during performance of behavioral tasks.