117 research outputs found
Retrospective: Adjusting Contaminant Concentrations in Bird Eggs to Account for Moisture and Lipid Loss During Their Incubation
By the 1960s, research and monitoring efforts on chlorinated
pesticide residues in tissues of wildlife were well
underway in North America and Europe. Conservationists
and natural resource managers were attempting to resolve
whether pesticide exposure and accumulated residues were
related to population declines in several species of predatory
and scavenging birds (e.g., bald eagle Haliaeetus
leucocephalus, peregrine falcon Falco peregrinus, brown
pelican Pelecanus occidentalis and osprey Pandion haliaetus).
The avian egg was a favored sampling matrix even
before the realization that eggshell thinning was linked to
population declines (Ratcliffe 1967; Hickey and Anderson
1968) and that the concentration of p,pâ-DDE in an egg was
associated with the shell thinning phenomenon (e.g., Blus
et al. 1972; Wiemeyer et al. 1988). The necessity for
making wet-weight concentration adjustments to account
for natural moisture loss during incubation of viable eggs
was realized. Correction for the more dramatic moisture
loss in non-viable decaying eggs was recognized as being
paramount. For example, the âDDT residues in osprey
eggs were reported to vary by as much as eightfold without
accounting for moisture loss adjustments (Stickel et al.
1965). In the absence of adjusting concentrations to the
fresh wet-weight that was present at the time of egg laying,
the uncorrected values exaggerated contaminant concentrations,
yielding artifactual results and ultimately incorrect
conclusions. The adjustment to fresh wet-weight concentration
is equally important for many other persistent
contaminants including PCBs, dioxins, furans, and brominated
diphenyl ethers
Movement primitives with multiple phase parameters
Movement primitives are concise movement representations that can be learned from human demonstrations, support generalization to novel situations and modulate the speed of execution of movements. The speed modulation mechanisms proposed so far are limited though, allowing only for uniform speed modulation or coupling changes in speed to local measurements of forces, torques or other quantities. Those approaches are not enough when dealing with general velocity constraints. We present a movement primitive formulation that can be used to non-uniformly adapt the speed of execution of a movement in order to satisfy a given constraint, while maintaining similarity in shape to the original trajectory. We present results using a 4-DoF robot arm in a minigolf setup
Education can improve the negative perception of a threatened long-lived scavenging bird, the Andean condor
Human-wildlife conflicts currently represent one of the main conservation problems for wildlife species around the world. Vultures have serious conservation concerns, many of which are related to people's adverse perception about them due to the belief that they prey on livestock. Our aim was to assess local perception and the factors influencing people's perception of the largest scavenging bird in South America, the Andean condor. For this, we interviewed 112 people from Valle FĂ©rtil, San Juan province, a rural area of central west Argentina. Overall, people in the area mostly have an elementary education, and their most important activity is livestock rearing. The results showed that, in general, most people perceive the Andean condor as an injurious species and, in fact, some people recognize that they still kill condors. We identified two major factors that affect this perception, the education level of villagers and their relationship with livestock ranching. Our study suggests that conservation of condors and other similar scavengers depends on education programs designed to change the negative perception people have about them. Such programs should be particularly focused on ranchers since they are the ones who have the worst perception of these scavengers. We suggest that highlighting the central ecological role of scavengers and recovering their cultural value would be fundamental to reverse their persecution and their negative perception by people.Fil: Cailly Arnulphi, VerĂłnica BeatrĂz. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas FĂsicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Lambertucci, Sergio Agustin. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Borghi, Carlos Eduardo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas FĂsicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; Argentin
Participatory game prototyping â balancing domain content and playability in a serious game design for the energy transition
Game design mostly engages future players as users and testers, whereas in the field of serious game design, approaches involving players more substantially are slowly emerging. This paper documents the participatory prototyping process of Energy Safari, a serious game for the energy transition in the Province of Groningen, and reports on the differences of the contributions made to the game development by separate groups of stakeholders. Each group contributed the most to the game elements that are most relevant to their interests. Overall, this study points to the potential of participatory game prototyping as a method to develop serious games that are balanced both in terms of domain content and playability, are meaningful for future players, and well embedded in the local context
Modelling the impact of toxic and disturbance stress on white-tailed eagle (Haliaeetus albicilla) populations
Several studies have related breeding success and survival of sea eagles to toxic or non-toxic stress separately. In the present investigation, we analysed single and combined impacts of both toxic and disturbance stress on populations of white-tailed eagle (Haliaeetus albicilla), using an analytical single-species model. Chemical and eco(toxico)logical data reported from laboratory and field studies were used to parameterise and validate the model. The model was applied to assess the impact of âPCB, DDE and disturbance stress on the white-tailed eagle population in The Netherlands. Disturbance stress was incorporated through a 1.6% reduction in survival and a 10â50% reduction in reproduction. âPCB contamination from 1950 up to 1987 was found to be too high to allow the return of white-tailed eagle as a breeding species in that period. âPCB and population trends simulated for 2006â2050 suggest that future population growth is still reduced. Disturbance stress resulted in a reduced population development. The combination of both toxic and disturbance stress varied from a slower population development to a catastrophical reduction in population size, where the main cause was attributed to the reduction in reproduction of 50%. Application of the model was restricted by the current lack of quantitative doseâresponse relationships between non-toxic stress and survival and reproduction. Nevertheless, the model provides a first step towards integrating and quantifying the impacts of multiple stressors on white-tailed eagle populations
Retrospective: Adjusting Contaminant Concentrations in Bird Eggs to Account for Moisture and Lipid Loss During Their Incubation
By the 1960s, research and monitoring efforts on chlorinated
pesticide residues in tissues of wildlife were well
underway in North America and Europe. Conservationists
and natural resource managers were attempting to resolve
whether pesticide exposure and accumulated residues were
related to population declines in several species of predatory
and scavenging birds (e.g., bald eagle Haliaeetus
leucocephalus, peregrine falcon Falco peregrinus, brown
pelican Pelecanus occidentalis and osprey Pandion haliaetus).
The avian egg was a favored sampling matrix even
before the realization that eggshell thinning was linked to
population declines (Ratcliffe 1967; Hickey and Anderson
1968) and that the concentration of p,pâ-DDE in an egg was
associated with the shell thinning phenomenon (e.g., Blus
et al. 1972; Wiemeyer et al. 1988). The necessity for
making wet-weight concentration adjustments to account
for natural moisture loss during incubation of viable eggs
was realized. Correction for the more dramatic moisture
loss in non-viable decaying eggs was recognized as being
paramount. For example, the âDDT residues in osprey
eggs were reported to vary by as much as eightfold without
accounting for moisture loss adjustments (Stickel et al.
1965). In the absence of adjusting concentrations to the
fresh wet-weight that was present at the time of egg laying,
the uncorrected values exaggerated contaminant concentrations,
yielding artifactual results and ultimately incorrect
conclusions. The adjustment to fresh wet-weight concentration
is equally important for many other persistent
contaminants including PCBs, dioxins, furans, and brominated
diphenyl ethers
Predicting Short-Term HR Response to Varying Training Loads Using Exponential Equations
Aim of this study was to test whether a monoexponential formula is appropriate
to analyze and predict individual responses to the change of load bouts online
during training. Therefore, 234 heart rate (HR) data sets obtained from extensive
interval protocols of four participants during a twelve-week training intervention
on a bike ergometer were analyzed. First, HR for each interval was approximated
using a monoexponential formula. HR at onset of exercise (HRstart), HR induced
by load (HRsteady) and the slope of HR (c) were analyzed. Furthermore, a
calculation routine incrementally predicted HRsteady using measured HR data after
onset of exercise. Validity of original and approximated data sets were very high
(rÂČ =0.962, SD =0.025; Max =0.991, Min =0.702). HRstart was significantly
different between all participants (one exception). HRsteady was similar in all
participants. Parameter c was independent of the duration of intervention and
intervals regarding one training session but was significantly different in all
participants (one exception). Final HR was correctly predicted on average after
58.8 s (SD = 34.77, Max =150 s, Min =30 s) based on a difference criteria of less
than 5 bpm. In 3 participants, HRsteady was predicted correctly in 142 out of 175
courses (81.1%)
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