scholarly journals Gadfly petrels use knowledge of the windscape, not memorized foraging patches, to optimize foraging trips on ocean-wide scales

2020 ◽  
Vol 287 (1918) ◽  
pp. 20191775 ◽  
Author(s):  
Francesco Ventura ◽  
José Pedro Granadeiro ◽  
Oliver Padget ◽  
Paulo Catry
Keyword(s):  
A Priori ◽  
Regional Scale ◽  
Foraging Strategy ◽  
Gps Tracking ◽  
Flight Behaviour ◽  
Dynamic Soaring ◽  
Soaring Flight ◽  
Wind Regimes ◽  
Fine Tune

Seabirds must often travel vast distances to exploit heterogeneously distributed oceanic resources, but how routes and destinations of foraging trips are optimized remains poorly understood. Among the seabirds, gadfly petrels ( Pterodroma spp.) are supremely adapted for making efficient use of wind energy in dynamic soaring flight. We used GPS tracking data to investigate the role of wind in the flight behaviour and foraging strategy of the Desertas petrel, Pterodroma deserta . We found that rather than visiting foraging hotspots, Desertas petrels maximize prey encounter by covering some of the longest distances known in any animal in a single foraging trip (up to 12 000 km) over deep, pelagic waters. Petrels flew with consistent crosswind (relative wind angle 60°), close to that which maximizes their groundspeed. By combining state–space modelling with a series of comparisons to simulated foraging trips (reshuffled-random, rotated, time-shifted, reversed), we show that this resulted in trajectories that were close to the fastest possible, given the location and time. This wind use is thus consistent both with birds using current winds to fine-tune their routes and, impressively, with an a priori knowledge of predictable regional-scale wind regimes, facilitating efficient flight over great distances before returning to the home colony.

Role of inherited structures and magmatism in North Tanzania from high resolution teleseismic P and S body-wave tomographies.

2021 ◽  
Author(s):  
Stéphanie Gautier ◽  
Adeline Clutier ◽  
Christel Tiberi ◽  
Fleurice Parat ◽  
Benoit Gibert ◽  
...  
Keyword(s):  
Body Wave ◽  
A Priori ◽  
Regional Scale ◽  
Velocity Model ◽  
S Wave ◽  
Fine Grid ◽  
Local Tomography ◽  
The North ◽  
Velocity Anomalies

<p>The North Tanzanian Divergence (NTD) is a zone of rift initiation. Its surface expression results from interactions between deep-mantle (mantle plume), lithospheric (inherited rheology and stratification, melting...) and crustal (dyke propagation, fault activation...) processes. However, the role of each process on the observed surface activity is still debated, because highly difficult to decorrelate.</p><p>We recently carried out a study to obtain enhanced P and S-wave tomography, from the surface down to 150-200 km depth. The particularity of our method consists in its initial velocity model. It is composed of a 1D IASP91 regional velocity model in which we inserted an a priori 3D crustal velocity model with a fine grid. This crustal model was deduced from an independent local tomography inversion.</p><p>The P and S images obtained, resulting from the teleseismic inversion of this hybrid method, show strong contrasted velocity anomalies: from 10 % of P (Vp) and S velocity (Vs) variation on the craton, to -17 % below the rift axis. The anomalies locations are consistent with the surface geology (rifting basin, border faults, volcanoes). At a regional scale, the strongest velocity contrasts correspond to the lithospheric inherited structure (Tanzanian craton and Proterozoic belts) boundaries, which control the propagation of the rift. In particular, the Masai cratonic block, south of the NTD, is inferred to have a strong influence in the rift evolution. The transition from the North-South axial valley into three diverging rift arms (Eyasi, Natron-Manyara and Pangani) is likely due to the change in rheology and to the presence of magma along inherited sutures between the craton and the mobile belts.</p><p>However, interrogations about the role of the thermal changes, the melt/fluid presence and the mantle composition in the NTD on these velocity anomalies still remain. To distinguish which parameters are acting in the rift, we realize a Vp/Vs ratio map. With this new data, and in the light of parallel petrological studies, we interpret the Vp/Vs anomalies in term of gas and/or melt concentration zones.</p>

scholarly journals Parametric Jensen-Shannon Statistical Complexity and Its Applications on Full-Scale Compartment Fire Data

Symmetry ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 22
Author(s):  
Flavia-Corina Mitroi-Symeonidis ◽  
Ion Anghel ◽  
Nicușor Minculete
Keyword(s):  
A Priori ◽  
Permutation Entropy ◽  
Compartment Fire ◽  
Symmetric Duality ◽  
Essential Step ◽  
Statistical Complexity ◽  
Theoretical Assumptions ◽  
Parametric Version ◽  
Fine Tune

The order/disorder characteristics of a compartment fire are researched based on experimental data. From our analysis performed by new, pioneering methods, we claim that the parametric Jensen-Shannon complexity can be successfully used to detect unusual data, and that one can use it also as a means to perform relevant analysis of fire experiments. Thoroughly comparing the performance of different algorithms (known as permutation entropy and two-length permutation entropy) to extract the probability distribution is an essential step. We discuss some of the theoretical assumptions behind each step and stress that the role of the parameter is to fine-tune the results of the Jensen-Shannon statistical complexity. Note that the Jensen-Shannon statistical complexity is symmetric, while its parametric version displays a symmetric duality due to the a priori probabilities used.

scholarly journals Understanding Determinants of Hunting Trip Productivity in an Arctic Community

2021 ◽  
Vol 5 ◽  
Author(s):  
Angus W. Naylor ◽  
Tristan Pearce ◽  
James D. Ford ◽  
David Fawcett ◽  
Peter Collings ◽  
...  
Keyword(s):  
Linear Regression ◽  
Regression Model ◽  
Linear Regression Model ◽  
Tracking System ◽  
A Priori ◽  
Gps Tracking ◽  
Annual Productivity ◽  
Heating Fuel ◽  
Main Variable

We examine factors underlying hunting productivity among Inuit in Ulukhaktok, Northwest Territories, Canada. Specifically, we focus on the role of gasoline use as the main variable of interest—commonly cited as a crucial determinant of hunting participation. Over the course of 12 months, 10 hunters recorded their on-the-land activities using a GPS tracking system, participatory mapping sessions, and bi-weekly interviews. A multivariable linear regression model (MvLRM) was applied to assess whether factors such as consumables used (i.e. heating fuel, gasoline, oil, food), distances traveled, or the number of companions on a trip were associated with the mass of edible foods returned to the community. Results indicate that, despite being positively associated with hunting trip productivity when assessed through a univariable linear regression model, gasoline is not a statistically significant determinant of standalone trip yield when adjusting for other variables in a multivariable linear regression. Instead, factors relating to seasonality, number of companions, and days on the land emerged as more significant and substantive drivers of productivity while out on the land. The findings do not suggest that access to, or the availability of, gasoline does not affect whether a hunting trip commences or is planned, nor that an increase in the amount of gasoline available to a hunter might increase the frequency of trips (and therefore annual productivity). Rather, this work demonstrates that the volume of gasoline used by harvesters on standalone hunting trips represent a poor a priori predictor of the edible weight that harvesters are likely to return to the community.

Collection of Ego-Centered Network Data with Computer-Assisted Interviews

Methodology ◽  
2006 ◽  
Vol 2 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Joachim Gerich ◽  
Roland Lehner
Keyword(s):  
Survey Methods ◽  
A Priori ◽  
Dynamic Structure ◽  
Computer Assisted ◽  
Network Data ◽  
Great Effort ◽  
Self Administration ◽  
Face To Face ◽  
Full Network

Although ego-centered network data provide information that is limited in various ways as compared with full network data, an ego-centered design can be used without the need for a priori and researcher-defined network borders. Moreover, ego-centered network data can be obtained with traditional survey methods. However, due to the dynamic structure of the questionnaires involved, a great effort is required on the part of either respondents (with self-administration) or interviewers (with face-to-face interviews). As an alternative, we will show the advantages of using CASI (computer-assisted self-administered interview) methods for the collection of ego-centered network data as applied in a study on the role of social networks in substance use among college students.

Disrupted Salience and Cingulo-Opercular Network Connectivity During Impaired Rapid Instructed Task Learning in Schizophrenia

2021 ◽  
pp. 216770262095934
Author(s):  
Julia M. Sheffield ◽  
Holger Mohr ◽  
Hannes Ruge ◽  
Deanna M. Barch
Keyword(s):  
A Priori ◽  
Network Connectivity ◽  
Task Learning ◽  
Human Ability ◽  
Functional Brain Networks ◽  
Task Goals ◽  
Multivariate Pattern ◽  
And Control ◽  
Goal Directed Behavior

Rapid instructed task learning (RITL) is the uniquely human ability to transform task information into goal-directed behavior without relying on trial-and-error learning. RITL is a core cognitive process supported by functional brain networks. In patients with schizophrenia, RITL ability is impaired, but the role of functional network connectivity in these RITL deficits is unknown. We investigated task-based connectivity of eight a priori network pairs in participants with schizophrenia ( n = 29) and control participants ( n = 31) during the performance of an RITL task. Multivariate pattern analysis was used to determine which network connectivity patterns predicted diagnostic group. Of all network pairs, only the connectivity between the cingulo-opercular network (CON) and salience network (SAN) during learning classified patients and control participants with significant accuracy (80%). CON-SAN connectivity during learning was significantly associated with task performance in participants with schizophrenia. These findings suggest that impaired interactions between identification of salient stimuli and maintenance of task goals contributes to RITL deficits in participants with schizophrenia.

scholarly journals EpCAM promotes endosomal modulation of the cortical RhoA zone for epithelial organization

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cécile Gaston ◽  
Simon De Beco ◽  
Bryant Doss ◽  
Meng Pan ◽  
Estelle Gauquelin ◽  
...  
Keyword(s):  
Cell Shape ◽  
Specific Protein ◽  
Cell Polarization ◽  
Stress Fiber ◽  
Fiber Formation ◽  
Endosomal Trafficking ◽  
Transient Zone ◽  
And Behavior ◽  
Fine Tune

AbstractAt the basis of cell shape and behavior, the organization of actomyosin and its ability to generate forces are widely studied. However, the precise regulation of this contractile network in space and time is unclear. Here, we study the role of the epithelial-specific protein EpCAM, a contractility modulator, in cell shape and motility. We show that EpCAM is required for stress fiber generation and front-rear polarity acquisition at the single cell level. In fact, EpCAM participates in the remodeling of a transient zone of active RhoA at the cortex of spreading epithelial cells. EpCAM and RhoA route together through the Rab35/EHD1 fast recycling pathway. This endosomal pathway spatially organizes GTP-RhoA to fine tune the activity of actomyosin resulting in polarized cell shape and development of intracellular stiffness and traction forces. Impairment of GTP-RhoA endosomal trafficking either by silencing EpCAM or by expressing Rab35/EHD1 mutants prevents proper myosin-II activity, stress fiber formation and ultimately cell polarization. Collectively, this work shows that the coupling between co-trafficking of EpCAM and RhoA, and actomyosin rearrangement is pivotal for cell spreading, and advances our understanding of how biochemical and mechanical properties promote cell plasticity.

scholarly journals The Role of Global Appearance of Omnidirectional Images in Relative Distance and Orientation Retrieval

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3327
Author(s):  
Vicente Román ◽  
Luis Payá ◽  
Adrián Peidró ◽  
Mónica Ballesta ◽  
Oscar Reinoso
Keyword(s):  
Mobile Robotics ◽  
A Priori ◽  
Computational Cost ◽  
Relevant Information ◽  
Local Features ◽  
New Family ◽  
Lighting Conditions ◽  
Omnidirectional Images ◽  
Great Development

Over the last few years, mobile robotics has experienced a great development thanks to the wide variety of problems that can be solved with this technology. An autonomous mobile robot must be able to operate in a priori unknown environments, planning its trajectory and navigating to the required target points. With this aim, it is crucial solving the mapping and localization problems with accuracy and acceptable computational cost. The use of omnidirectional vision systems has emerged as a robust choice thanks to the big quantity of information they can extract from the environment. The images must be processed to obtain relevant information that permits solving robustly the mapping and localization problems. The classical frameworks to address this problem are based on the extraction, description and tracking of local features or landmarks. However, more recently, a new family of methods has emerged as a robust alternative in mobile robotics. It consists of describing each image as a whole, what leads to conceptually simpler algorithms. While methods based on local features have been extensively studied and compared in the literature, those based on global appearance still merit a deep study to uncover their performance. In this work, a comparative evaluation of six global-appearance description techniques in localization tasks is carried out, both in terms of accuracy and computational cost. Some sets of images captured in a real environment are used with this aim, including some typical phenomena such as changes in lighting conditions, visual aliasing, partial occlusions and noise.

scholarly journals Visualization approaches to support healthy aging: A systematic review

2016 ◽  
Vol 23 (3) ◽  
pp. 600 ◽  
Author(s):  
Uba Backonja ◽  
Nai-Ching Chi ◽  
Yong Choi ◽  
Amanda K Hall ◽  
Thai Le ◽  
...  
Keyword(s):  
Older Adults ◽  
Health Behaviors ◽  
Healthy Aging ◽  
A Priori ◽  
Aging In Place ◽  
Future Research ◽  
Health Technologies ◽  
Data Visualizations ◽  
Informatics Tools

Background: Health technologies have the potential to support the growing number of older adults who are aging in place. Many tools include visualizations (data visualizations, visualizations of physical representations). However, the role of visualizations in supporting aging in place remains largely unexplored.Objective: To synthesize and identify gaps in the literature evaluating visualizations (data visualizations and visualizations of physical representations), for informatics tools to support healthy aging.Methods: We conducted a search in CINAHL, Embase, Engineering Village, PsycINFO, PubMed, and Web of Science using a priori defined terms for publications in English describing community-based studies evaluating visualizations used by adults aged ≥65 years.Results: Six out of the identified 251 publications were eligible. Most studies were user studies and varied methodological quality. Three visualizations of virtual representations supported performing at-home exercises. Participants found visual representations either (a) helpful, motivational, and supported their understanding of their health behaviors or (b) not an improvement over alternatives. Three data visualizations supported understanding of one’s health. Participants were able to interpret data visualizations that used precise data and encodings that were more concrete better than those that did not provide precision or were abstract. Participants found data visualizations helpful in understanding their overall health and granular data.Conclusions: Studies we identified used visualizations to promote engagement in exercises or understandings of one’s health. Future research could overcome methodological limitations of studies we identified to develop visualizations that older adults could use with ease and accuracy to support their health behaviors and decision-making.

scholarly journals Surveying Potential Vectors of Apple Proliferation Phytoplasma: Faunistic Analysis and Infection Status of Selected Auchenorrhyncha Species

Insects ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 12
Author(s):  
Stefanie Fischnaller ◽  
Martin Parth ◽  
Manuel Messner ◽  
Robert Stocker ◽  
Christine Kerschbamer ◽  
...  
Keyword(s):  
New Records ◽  
Regional Scale ◽  
Insect Vectors ◽  
Infection Status ◽  
Apple Proliferation ◽  
Population Densities ◽  
South Tyrol ◽  
Candidatus Phytoplasma Mali ◽  
Cacopsylla Melanoneura

Apple proliferation (AP) is one of the economically most important diseases in European apple cultivation. The disease is caused by the cell-wall-less bacterium ’ Candidatus Phytoplasma mali’, which is transmitted by Cacopsylla picta (Foerster) and Cacopsylla melanoneura (Foerster) (Hemiptera: Psylloidea). In South Tyrol (Italy), severe outbreaks were documented since the 1990s. Infestation rates of AP do not always correlate with the population densities of the confirmed vectors, implying the presence of other, so far unknown, hemipterian vectors. By elucidating the species community of Auchenorrhyncha (Insecta: Hemiptera) at a regional scale, more than 31,000 specimens were captured in South Tyrolean apple orchards. The occurrence of 95 species was confirmed, whereas fourteen species are new records for this territory. Based on the faunistical data, more than 3600 individuals out of 25 species were analyzed using quantitative PCR to assess the presence of AP phytoplasma. The pathogen was sporadically detected in some individuals of different species, for example in Stictocephala bisonia Kopp and Yonk (Hemiptera: Membracidae). However, the concentration of phytoplasma was much lower than in infected C. picta and C. melanoneura captured in the same region, confirming the role of the latter mentioned psyllids as the main insect vectors of AP- phytoplasma in South Tyrol.

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