NEOTROPICAL FRESHWATER FISHES: A dataset of occurrence and abundance of freshwater fishes in the Neotropics

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.

Diversidade de peixes de tributários do reservatório de Chavantes, PR, bacia do alto rio Paraná

http://dx.doi.org/10.5007/2175-7925.2016v29n2p33A distribuição e abundância das espécies de peixes de riacho podem ser influenciadas por características ambientais relacionadas ao meio aquático e às suas margens. O objetivo do presente trabalho foi inventariar a fauna de peixes dos riachos da Cruz, Taquaruçu e Taquaruçu II, localizados na bacia do rio Paranapanema, analisando parâmetros de diversidade da ictiofauna e associando-os com variáveis abióticas. Foram coletados 4.956 exemplares, distribuídos em 27 espécies, com predominância de Characiformes e Siluriformes. A largura, a profundidade e a floresta ripária foram as variáveis ambientais que melhor explicaram a diversidade de espécies encontrada no riacho Taquaruçu II, enquanto a dominância de espécies nos riachos da Cruz e Taquaruçu pode refletir os impactos antrópicos presentes nestes ambientes, como alto grau de erosão das margens. A maior similaridade da ictiofauna entre os riachos da Cruz e Taquaruçu pode estar relacionada com suas conectividades hidrológicas. A condutividade elétrica e a largura dos riachos foram as variáveis abióticas que mais se correlacionaram com a abundância e diversidade de espécies nos riachos amostrados. Os resultados do presente estudo demonstram a importância da conservação dos ecossistemas aquáticos para a manutenção da diversidade de peixes, além de alertar para o efeito de impactos antropogênicos sobre a ictiofauna.

Searching chaos and coherent structures in the atmospheric turbulence above the Amazon forest

In this work, the possible chaotic nature of the atmospheric turbulence above a densely forested area in the Amazon region is investigated. To this end, we use high-resolution temperature data obtained during a micrometeorological measurement campaign in the Brazilian Amazonia. Estimates of the correlation dimension (D(2)=3.50+/-0.05) and of the largest Lyapunov exponent (lambda(1)=0.050+/-0.002) suggest the existence of chaos in the atmospheric boundary layer. Our findings indicate that this low-dimensional chaotic dynamics is associated with the presence of the coherent structures within the boundary layer right above the canopy top and not with the atmospheric turbulence per se, as previously claimed.

High-dimensional interior crisis in the Kuramoto-Sivashinsky equation

An investigation of interior crisis of high dimensions in an extended spatiotemporal system exemplified by the Kuramoto-Sivashinsky equation is reported. It is shown that unstable periodic orbits and their associated invariant manifolds in the Poincaré hyperplane can effectively characterize the global bifurcation dynamics of high-dimensional systems.

Reported chronic insomnia is independent of poor sleep as measured by electroencephalography

OBJECTIVE

Several behavioral, physiological, and subjective variables were examined in subjects reporting chronic insomnia (IN group) and subjects with no complaint of insomnia (NC group) to determine factors predictive of poor sleep as measured by electroencephalography (EEG sleep).

METHODS

A total of 177 subjects (121 in the IN group and 56 in the NC group) were evaluated on the basis of EEG sleep, subjective sleep, sleepiness, performance, mood, personality, and metabolic parameters during a 36-hour laboratory stay.

RESULTS

Equal percentages of subjects in each group had 0, 1, or 2 nights of poor EEG sleep, indicating that the IN group was not more likely to have impaired sleep in the laboratory. Results of the Minnesota Multiphasic Personality Inventory showed that subjects in the IN group had more pathological personality profiles, and results of laboratory studies showed that these subjects had worse mood ratings, less subjective sleepiness, poorer memory performance, and longer midafternoon sleep latencies. Subjects in the IN group also rated their laboratory sleep as poorer in quality with more time awake after sleep onset and longer sleep latencies, but no differences in EEG sleep were observed. Poor nights of EEG sleep were associated with being male, increasing age, and a history of more time awake after sleep onset; among the laboratory tests, poor EEG sleep was associated with worse mood ratings, poorer memory performance, longer sleep latencies (as indicated by higher scores on the Multiple Sleep Latency Test), higher sleep/wake ratios for metabolic parameters, lower ratings of sleep quality, and longer perceived sleep latencies.

CONCLUSIONS

A history of chronic insomnia does not predict poor EEG sleep. Both chronic insomnia and poor EEG sleep are associated independently with dysphoria, hyperarousal, diminished waking function, and negative subjective sleep quality. Separate arousal and sleep systems are posited to account for these results.

Work schedule and task factors in upper-extremity fatigue

We tested the combined effects of work schedule and task factors on upper-extremity fatigue in the laboratory during 8-h and 12-h shift schedules. Participants performed a simulated manual assembly task at three repetition rates and three torque loads and self-adjusted their work cycle duration to maintain fatigue at moderate levels. Work cycle durations decreased with increases in both load level and repetition rate. Fatigue was observed more quickly with increasing time on shifts and during night shifts compared with day shifts. Work schedule effects were most apparent at lighter workloads, with minimal differences at higher workloads. The highest fatigue levels were observed during 12-h night shifts, with similar levels reached by the end of both the week of 8-h night shifts and the week of 12-h day shifts. Overall durations were 20%-30% shorter than in previous short-term studies, which was likely a result of the more realistic work schedules used in this study. Results from this study could be applied to the design of work-rest schedules for manual tasks involving the upper extremities.

Rescheduling a three shift system at a steel rolling mill: effects of a one hour delay of shift starting times on sleep and alertness in younger and older workers

OBJECTIVE

To evaluate a new work schedule at a Finnish steel mill with special attention to effects on older workers. The schedule was designed to improve sleep before the morning shift, and alertness during the morning shift, by delaying shift start and end times.

METHODS

Evaluation was by a shiftwork health and safety questionnaire, recordings of work-rest-sleep cycles with activity monitors worn on the wrist, daily diaries, and on site computerised testing of fatigue and alertness by the NIOSH fatigue test battery.

RESULTS

The one hour delay in shift starting times improved sleep before the morning shift, and improved waking fatigue, sleepiness, and performance during the morning shift. Evening and night shift sleep and fatigue or sleepiness, however, were affected negatively by the new work schedule, but the results for those shifts were less consistent across the various measures. Despite the improvements, most workers were not satisfied with the new schedule because of social concerns. Few interactions of age with the new work schedule were found, suggesting that the effects of the work schedule were uniform across age groups.

CONCLUSION

A change of as little as one hour in shift starting times can improve morning shift sleep and alertness, but there are trade offs from these improvements in terms of night shift effects and social considerations. It seems, then, that optimal shift start and end times for an entire organisation are difficult to institute on a wide scale. Tailoring shift schedules to subgroups within an organisation is suggested.

Extended workshifts and excessive fatigue

Studies of overtime have pointed to fatigue as a potential factor producing, for example, a three-fold increase in accident rate after 16 h of work, increases in back injuries, hospital outbreaks of bacterial infection, or nuclear-power plant safety compromises. Fatigue has been measured more directly in studies of scheduled long workshifts, where performance decrements in both work-related tasks and laboratory-type behavioural tests have been observed, and significant loss of sleep and increases in subjective sleepiness have been reported. Analyses of accidents or injuries during scheduled extended workshifts, however, have produced equivocal results. Factors which could compound the fatiguing effects of extended workshifts, such as workload, noise, chemical exposure, or duties and responsibilities outside of the workplace, rarely have been studied systematically. It is concluded that extended workshift schedules should be instituted cautiously and evaluated carefully, with appropriate attention given to staffing levels, workload, job rotation, environmental exposures, emergency contingencies, rest breaks, commuting time, and social or domestic responsibilities.

Napping at home and alertness on the job in rotating shift workers

Conditions surrounding self-selected napping and its association with waking function were examined in a quasi-experimental study at two worksites with workers on 8- and 12-hour rotating shifts. Nap frequency, sleep quantity, quality and timing were determined from daily questionnaires, and performance/alertness during the workshift was assessed with on-site computerized testing. Results indicated that most napping occurred prior to the first night shift of the week. Napping prior to the first shift supplemented an apparently adequate quantity of main sleep, whereas napping during the workweek compensated for a reduced quantity of main sleep. Sleep quality was rated higher on no-nap days than on nap days and higher prior to the first shift than during the workweek. These results generally support a compensatory view of napping. Worksite performance/alertness testing, however, indicated diminished alertness during the shift on nap days compared to no-nap days, which was not consistent with a compensatory view of napping. Decreased alertness on nap days may have been associated with poorer sleep quality or with differences in circadian rhythm adaptation on those days.

Psychophysical determinants of stress in sustained attention

To date, research on the stress of sustained attention tasks has not explored the extent to which such stress is determined by the psychophysical aspects of the monitored display. In the present study, the effects of the sensory modality of signals (audition and vision) and the background event rate (5 and 40 events/min) on task-induced stress were examined in a vigilance situation. Critical signals for detection were slight changes in stimulus duration. Stress was indexed by motor restlessness and subjective reports of fatigue. Restlessness and subjective fatigue increased dramatically across a 50-min watch in all conditions. Stress effects were most notable in the case of visual monitoring but were unrelated to variations in event rate. Hence, from a psychophysical perspective, the stress of sustained attention seems to be identified more specifically with the sensory modality of signals than with the event rate context in which they appear.

Performance and alertness on 8 h and 12 h rotating shifts at a natural gas utility

An 8 h/5-7 day shift schedule was compared with a newly instituted 12 h/2-4 day schedule in this, our second worksite study of extended workshifts. Workers completed a performance/alertness test battery, and a questionnaire on sleep patterns and other personal habits, 2-4 times a week on all shifts. After 10 months adaptation to the 12 h shift schedule, there were decrements in performance/alertness attributable to the extra 4 h on the extended shift. There were also reductions in sleep across the workweek which were most apparent on 12 h night shifts. The results are consistent with our first worksite study of 12 h shifts and indicate extra caution should be exercised when scheduling critical activities for extended workshifts, especially extended night shifts.

Demand transitions and sustained attention

A recent report by the National Research Council (Huey & Wickens, 1993) has identified transitions in task demand as an important dimension for study in vigilance research. This experiment tested the possibility that the effects of such transitions follow a relatively simple psychophysical rule--they are characterized by contrast effects. Transitions in task demand were achieved by shifting subjects from single-task to dual-task monitoring and vice versa. These transitions produced changes in subjects' sensing and decision-making functions that were far more intricate than simple contrast effects. The demand transition issue offers a complex research challenge on both basic and applied levels and warrants further investigation.

Intervention factors for promoting adjustment to nightwork and shiftwork

This chapter reviews a broad range of factors that, if controlled, might promote adaptation to nightwork, shiftwork, and extended workshifts. Systematic study has begun in four of the areas reported here: work schedule design, napping, bright light stimulation, and drugs. Physical activity, ambient temperature, diet, and individual behaviors have been studied only superficially.

Shiftwork effects on social and family life

Advantages and disadvantages of different work schedules--fixed days, fixed afternoons, fixed nights, and rotating shifts--are reviewed in terms of social satisfaction and adjustment for the worker and his or her family. The chapter also calls for new studies assessing the impact of changes in the complexion of the workforce and composition of the American family on shiftworker satisfaction.

Sleep and performance in young adults and older normals and insomniacs during acute sleep loss and recovery

Many changes occur in sleep as a function of aging, but it is not known whether these changes result in sleep being less restorative. To examine the sleep restorative process, groups of 12 normal young adults and 12 normal and 12 insomniac male subjects, age 55-71, were totally sleep deprived for 64 hours and then allowed recovery sleep. Response speed, immediate recall, sleepiness, and body temperature were tested at approximately 2300, 0115, 0330, 0530 and 0800 during baseline, sleep loss, and recovery nights. Significant group (age or insomnia) by sleep loss condition interactions were found for reaction time and immediate recall performance measures. Similar significant interactions were found for oral temperature and all EEG sleep variables except total time in bed, percent stage 1, and percent REM. It was concluded that performance recovery following sleep loss was no slower in older subjects than in younger subjects despite very different recovery sleep stage parameters. This implied that aging effects on sleep are developmental rather than degenerative.

Sleep stages, auditory arousal threshold, and body temperature as predictors of behavior upon awakening

Attempts to demonstrate sleep stage effects on waking behavior have been equivocal at best. The present study provided a more sensitive approach to this problem by assessing performance and subjective alertness at repeated awakenings across baseline sleep and across recovery sleep following 40 and 64 hours of sleep deprivation. These behaviors were then compared to changes in EEG sleep, body temperature, and auditory threshold within these nights. Comparison of means between baseline and recovery sleep indicated that the behavioral variables were generally more sensitive than sleep stages to different amounts of prior wakefulness. Multiple regression analyses revealed no consistent covariation between behavior and any sleep stage which was independent of the correlations among the sleep stages themselves. Thus, distinct functions for specific sleep stages were not apparent from the comparison of means or the regression analyses. However, significant positive covariations were obtained between body temperature and performance, and auditory threshold and sleepiness. Significant negative covariations were obtained between body temperature and sleepiness, and auditory threshold and performance. From these results it was concluded that the most reliable predictors of behavior upon awakening were: the amount of wakefulness prior to sleep, the total amount of accrued sleep, circadian time as indexed by body temperature, and depth of sleep.

The relationship of sleep and anxiety in anxious subjects

The present study provided polysomnographic corroboration of the frequently reported relationship between anxiety and subjective sleep disturbance. When compared to normals, anxious individuals were found to have significantly less sleep period time, total sleep time, percent stage REM and percent stage 4; shorter latency to stage REM; and greater percent stage 1. Partial correlations (holding depression constant) showed significant positive relationships between anxiety rating and number of awakenings, latency to stage 1, and percent stage 2. A significant negative relationship was found between anxiety and percent stage 4, and a nonsignificant negative trend was found between anxiety and latency to stage REM. Overall there was a tendency toward less sleep and lighter sleep in subjects with anxiety, thus validating subjective reports. The decreased latency to stage REM and its negative relation to anxiety, raised the possibility that this variable may not be specifically indicative of depression.

[Quantification of diphtheria antibodies in guinea pigs. I. Persistence of serum antibody-levels in animals inoculated with a dose of diphtheria toxoid]

Foi estudado o comportamento da cinética de anticorpogénese em cobaias inoculadas com uma dose de toxóide diftérico precipitado pelo alúmen. Paralelamente, foi estudada a dinâmica da imunidade passiva naturalmente transmitida aos filhotes. Em cobaias vacinadas com uma dose de antígeno, foi verificado que a síntese de antitoxina diftérica persiste, em títulos detectáveis, até 36 meses após. Os anticorpos transferidos, passivamente, da mãe vacinada para os filhotes atingiram, nestes, concentrações plasmáticas superiores, sendo que a imunidade perdurou em títulos detectáveis até cerca de três meses de idade dos mesmos.

Effects of afternoon naps on physiological variables performance and self-reported activation

Fluctuations in physiological variables resulting from naps and the relationship of these to previously studies changes in performance and subjective activation associated with napping were examined. The subjects were eighteen healthy male university students who habitually slept 1/2-2 hr in the afternoon. Measurements were obtained of our physiological variables, from a continuous 10-min auditory reaction time task and two factors of an Activation. Deactivation Adjective Checklist 20 min before and after a control condition and two electroencephalographically recorded afternoons of sleep. The experimental conditions comprised a 2-hr period of wakefulness, a 1/2 hr nap from 4.35-5.05 p.m., and a 2-hr nap from 3.05-5.05 p.m. Following each sleep treatment, when compared with the control condition, there were statistically significant shifts of improved reaction time performance, and elevated activation as reflected by the two self-report scales, inceased EEG frequency, heart rate, and electrodermal responses. The shifts of increased behavioral efficiency, subjective and physiological activation were approximately equivalent in extent between 2-hr and 1/2-hr naps. These findings indicate that besides the previously reported facilitation by naps of performance and mood, physiological activation is increased following accustomed episodes of afternoon sleep.