187 research outputs found
Flower and fruit development of Parkia pendula (Fabaceae, Mimosoideae)
Parkia pendula occurs in Brazil in Amazonia and in the northeastern Atlantic Forest. In the latter, its buds, nectar, and seedpod gum are discussed to be keystone resources for the mammalian fauna. To enhance the knowledge about these important nourishment sources, the aim of this study was to detect and describe distinct phases in the flower and pod development. The study was conducted in a 306 ha forest fragment in Igarassu, Pernambuco, northeastern Brazil. Six morphometrical variables were measured weekly at five inflorescences of two individuals from September 2003 to January 2004. Eleven distinct developmental phases were identified in the 21 weeks lasting development from the very first inflorescences to mature pods and are described in detail. These phases are good predictors for the flowering and fruiting phenology of P. pendula, since they are easily distinguishable from the forest floor. Furthermore, highly synchronized abortions of inflorescences, buds, and pods were observed which support the previously assumed predator satiation defense strategy in Parkia.Parkia pendula ocorre no Brasil, tanto na Amazônia como na Mata Atlântica nordestina. Seus botões, néctar e goma da vagem são recursos chave para a mastofauna da Mata Atlântica nordestina. Para aumentar o conhecimento sobre estes importantes recursos alimentares, este estudo teve como objetivo detectar e descrever as diferentes fases de desenvolvimento de flores e frutos. Este trabalho foi realizado em um fragmento de Mata Atlântica de 306 ha em Igarassu, Pernambuco, Nordeste do Brasil. Entre setembro de 2003 e janeiro de 2004, seis variáveis morfométricas foram medidas semanalmente em cinco inflorescências de dois indivíduos. Onze fases distintas de desenvolvimento puderam ser identificadas e descritas em detalhe nas 21 semanas desde o desenvolvimento das primeiras inflorescências até as vagens maduras. Essas fases são boas preditoras da fenologia de floração e frutificação de P. pendula porque são distinguíveis facilmente do solo da floresta. Além disto, a observação de abortos sincronizados de inflorescências, botões e vagens corrobora a estratégia de defesa previamente sugerida para Parkia, de saciedade de predadores
Sleep deprivation decreases eye gaze entropy in women but not in men in a manual spacecraft docking task: indications of an adaptation of scanning strategy
INTRODUCTION
Fatigue is a pressing problem in driving, aviation, and spaceflight and represents a root cause of
15-20% of accidents in transportation operations. Changes in visual scanning efficiency have been
associated with sleep deprivation. This study investigates the effect of 24h of sleep deprivation on
scanning efficiency and spatial distribution of fixations by means of gaze entropy in a spacecraft
docking task, during which participants had to manually control a simulated spacecraft with 6 DoF.
METHODS
A counterbalanced crossover design with a sleep deprivation condition and a control condition was
used. Linear mixed models were applied to analyze the data of 61 participants between the ages of
20 and 39 years (M = 24.90, SD = 4.68) with 28 female participants. Subjective sleepiness ratings
were collected before each test session, wherein the participants conducted a sustained attention
task as well as the 6df task. During the test session, eye-tracking data was continuously recorded.
RESULTS
An interaction between sleep deprivation and gender of the participants significantly affected both
entropy measures. Female participants showed a significant decrease in gaze transition entropy (p
< .01) and stationary gaze entropy (p < .05) during sleep deprivation compared to male participants.
This suggests a reduction of scanning complexity and a more exploitative examination of the visual
scene, respectively, in response to sleepiness. A significant association between gaze transition
entropy and docking performance depending on trial difficulty was found (p < .05). Lower scanning
complexity (GTE) was linked to better performance, but only in easier trials.
CONCLUSION
Sleep deprivation leads to alterations of gaze behavior in female participants, possibly as an
adaptive reaction during a critical operational task. Women reduce their visual scanning
complexity, a change that was associated with better performance in easy trials. Future research
needs to identify optimal entropy ranges for specific docking maneuvers to guide docking training
and inform strategies to mitigate the impact of fatigu
BMJ Open
INTRODUCTION: Worldwide, 2 million patients aged 18-50 years suffer a stroke each year, and this number is increasing. Knowledge about global distribution of risk factors and aetiologies, and information about prognosis and optimal secondary prevention in young stroke patients are limited. This limits evidence-based treatment and hampers the provision of appropriate information regarding the causes of stroke, risk factors and prognosis of young stroke patients. METHODS AND ANALYSIS: The Global Outcome Assessment Life-long after stroke in young adults (GOAL) initiative aims to perform a global individual patient data meta-analysis with existing data from young stroke cohorts worldwide. All patients aged 18-50 years with ischaemic stroke or intracerebral haemorrhage will be included. Outcomes will be the distribution of stroke aetiology and (vascular) risk factors, functional outcome after stroke, risk of recurrent vascular events and death and finally the use of secondary prevention. Subgroup analyses will be made based on age, gender, aetiology, ethnicity and climate of residence. ETHICS AND DISSEMINATION: Ethical approval for the GOAL study has already been obtained from the Medical Review Ethics Committee region Arnhem-Nijmegen. Additionally and when necessary, approval will also be obtained from national or local institutional review boards in the participating centres. When needed, a standardised data transfer agreement will be provided for participating centres. We plan dissemination of our results in peer-reviewed international scientific journals and through conference presentations. We expect that the results of this unique study will lead to better understanding of worldwide differences in risk factors, causes and outcome of young stroke patients
The Osteology of the Basal Archosauromorph Tasmaniosaurus triassicus from the Lower Triassic of Tasmania, Australia
Proterosuchidae are the most taxonomically diverse archosauromorph reptiles sampled in the immediate aftermath of the Permo-Triassic mass extinction and represent the earliest radiation of Archosauriformes (archosaurs and closely related species). Proterosuchids are potentially represented by approximately 15 nominal species collected from South Africa, China, Russia, Australia and India, but the taxonomic content of the group is currently in a state of flux because of the poor anatomic and systematic information available for several of its putative members. Here, the putative proterosuchid Tasmaniosaurus triassicus from the Lower Triassic of Hobart, Tasmania (Australia),is redescribed. The holotype and currently only known specimen includes cranial and postcranial remains and the revision of this material sheds new light on the anatomy of the animal, including new data on the cranial endocast. Several bones are re-identified or reinterpreted, contrasting with the descriptions of previous authors. The new information provided here shows that Tasmaniosaurus closely resembles the South African proterosuchid Proterosuchus, but it differed in the presence of, for example, a slightly downturned premaxilla, a shorter anterior process of maxilla, and a diamond-shaped anterior end of interclavicle. Previous claims for the presence of gut contents in the holotype of Tasmaniosaurus are considered ambiguous. The description of the cranial endocast of Tasmaniosaurus provides for the first time information about the anatomy of this region in proterosuchids. The cranial endocast preserves possibly part of the vomero-nasal (= Jacobson's) system laterally to the olfactory bulbs. Previous claims of the absence of the vomero-nasal organs in archosaurs, which is suggested by the extant phylogenetic bracket, are questioned because its absence in both clades of extant archosaurs seems to be directly related with the independent acquisition of a non-ground living mode of life
Biological Earth observation with animal sensors.
Space-based tracking technology using low-cost miniature tags is now delivering data on fine-scale animal movement at near-global scale. Linked with remotely sensed environmental data, this offers a biological lens on habitat integrity and connectivity for conservation and human health; a global network of animal sentinels of environmen-tal change
Gifted children with ADHD: how are they different from non-gifted children with ADHD?
The present study focused on inattention and hyperactivity/impulsivity differences of gifted children with and without attention deficit-hyperactivity disorder (ADHD). Based on clinical assessment utilizing the Anxiety Disorders Interview Schedule for Children (ADISC-IV) and the Wechsler Intelligence Scale for Children—Fourth Edition, attendees of a public outpatient child service (boys = 359, girls = 148), with mean age 10.60 years (SD = 3.08 years), were allocated into four groups: ADHD (N = 350), gifted (N = 15), gifted/ADHD (N = 18), and clinical controls (N = 124). The Strengths and Weaknesses of ADHD-Symptoms and Normal Behavior Scale dimensionally assessed inattention and hyperactivity/impulsivity variations. Compared to the gifted/ADHD group, the ADHD group had higher scores for inattention and comparable scores for hyperactivity/impulsivity. For most symptoms, the ADHD groups (gifted or not) rated higher than the non-ADHD groups (control and gifted without ADHD). Findings appeared to indicate that (i) ADHD is a valid diagnosis among children who are gifted, (ii) gifted children might tend to be less inattentive than non-gifted ADHD children, and (iii) ADHD-gifted children appear to differ from the non-ADHD-gifted children with regard to specific hyperactive and impulsive behaviors. The practical implication of these findings is that clinicians may wish to focus on these symptoms when diagnosing ADHD among children with high intelligence
A next-generation liquid xenon observatory for dark matter and neutrino physics
The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector
A Next-Generation Liquid Xenon Observatory for Dark Matter and Neutrino Physics
The nature of dark matter and properties of neutrinos are among the mostpressing issues in contemporary particle physics. The dual-phase xenontime-projection chamber is the leading technology to cover the availableparameter space for Weakly Interacting Massive Particles (WIMPs), whilefeaturing extensive sensitivity to many alternative dark matter candidates.These detectors can also study neutrinos through neutrinoless double-beta decayand through a variety of astrophysical sources. A next-generation xenon-baseddetector will therefore be a true multi-purpose observatory to significantlyadvance particle physics, nuclear physics, astrophysics, solar physics, andcosmology. This review article presents the science cases for such a detector.<br
A next-generation liquid xenon observatory for dark matter and neutrino physics
The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector
- …
