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Sample records for extinct passenger pigeon

  1. Using Digital 3D Scanning to Create “Artifictions” of the Passenger Pigeon and Harelip Sucker, Two Extinct Species in Eastern North America: The Future Examines the Past

    Directory of Open Access Journals (Sweden)

    Bruce L. Manzano

    2015-12-01

    Full Text Available The Virtual Curation Laboratory at Virginia Commonwealth University created 3D representations of digital morphological models, termed “artifictions,” of several bone elements from two extinct animals, the passenger pigeon (Ectopistes migratorius Linnaeus Columbidae and the harelip sucker (Moxostoma lacerum Jordan and Brayton Catostomidae. Procuring recent comparative reference skeletons these species is extremely difficult. The creation of artifictions, 3D printed replicas of skeletal remains, aims to help researchers become familiar with the bones of harelip sucker and passenger pigeon to facilitate morphological identification of remains of these species within archaeological assemblages. Here, we discuss the two species, the techniques used to create digital topological models of individual skeletal elements, and the obstacles encountered regarding 3D printed artifictions in zooarchaeology.

  2. Extinction and spontaneous recovery of spatial behavior in pigeons.

    Science.gov (United States)

    Leising, Kenneth J; Wong, Jared; Blaisdell, Aaron P

    2015-10-01

    We investigated extinction and spontaneous recovery of spatial associations using a landmark-based appetitive search task in a touchscreen preparation with pigeons. Four visual landmarks (A, B, C, and D) were separately established as signals of a hidden reinforced target among an 8 × 7 array of potential target locations. The target was located above landmarks (LM) A and C and below B and D. After conditioning, A and B were extinguished. Responding to A and C was assessed on probe tests 2 days following extinction, whereas, B and D were tested 14 days after extinction. We observed spontaneous recovery from spatial extinction following a 14-day, but not a 2-day, postextinction retention interval. Furthermore, by plotting the spatial distribution of responding across the X and Y axes during testing, we found that spontaneous recovery of responding to the target in our task was due to enhanced spatial control (i.e., a change in the overall distribution of responses) following the long delay to testing. These results add spatial extinction and spontaneous recovery to the list of findings supporting the assertion that extinction involves new learning that attenuates the originally acquired response, and that original learning of the spatial relationship between paired events survives extinction. (PsycINFO Database Record

  3. Transient inactivation of the pigeon hippocampus or the nidopallium caudolaterale during extinction learning impairs extinction retrieval in an appetitive conditioning paradigm.

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    Lengersdorf, Daniel; Stüttgen, Maik C; Uengoer, Metin; Güntürkün, Onur

    2014-05-15

    The majority of experiments exploring context-dependent extinction learning employ Pavlovian fear conditioning in rodents. Since mechanisms of appetitive and aversive learning are known to differ at the neuronal level, we sought to investigate extinction learning in an appetitive setting. Working with pigeons, we established a within-subject ABA renewal paradigm based on Rescorla (Q J Exp Psychol 61:1793) and combined it with pharmacological interventions during extinction. From the fear conditioning literature, it is known that both prefrontal cortex and the hippocampus are core structures for context-specific extinction learning. Accordingly, we transiently inactivated the nidopallium caudolaterale (NCL, a functional analogue of mammalian prefrontal cortex) and the hippocampus in separate experiments by intracranial infusion of the sodium-channel blocker tetrodotoxin immediately before extinction training. We find that TTX in both structures non-specifically suppresses conditioned responding, as revealed by a reduction of response rate to both the extinguished conditioned stimulus and a control stimulus which remained reinforced throughout the experiment. Furthermore, TTX during extinction training impaired later extinction retrieval assessed under drug-free conditions. This was true when responding to the extinguished stimulus was assessed in the context of extinction but not when tested in the context of acquisition, although both contexts were matched with respect to their history of conditioning. These results indicate that both NCL and hippocampus are involved in extinction learning under appetitive conditions or, more specifically, in the consolidation of extinction memory, and that their contribution to extinction is context-specific.

  4. Not just passengers: pigeons, Columba livia, can learn homing routes while flying with a more experienced conspecific.

    Science.gov (United States)

    Pettit, Benjamin; Flack, Andrea; Freeman, Robin; Guilford, Tim; Biro, Dora

    2013-01-01

    For animals that travel in groups, the directional choices of conspecifics are potentially a rich source of information for spatial learning. In this study, we investigate how the opportunity to follow a locally experienced demonstrator affects route learning by pigeons over repeated homing flights. This test of social influences on navigation takes advantage of the individually distinctive routes that pigeons establish when trained alone. We found that pigeons learn routes just as effectively while flying with a partner as control pigeons do while flying alone. However, rather than learning the exact route of the demonstrator, the paired routes shifted over repeated flights, which suggests that the birds with less local experience also took an active role in the navigational task. The efficiency of the original routes was a key factor in how far they shifted, with less efficient routes undergoing the greatest changes. In this context, inefficient routes are unlikely to be maintained through repeated rounds of social transmission, and instead more efficient routes are achieved because of the interaction between social learning and information pooling.

  5. Notes on the extinct pigeon from Mauritius, Alectroenas nitidissima (Scopoli, 1786)

    NARCIS (Netherlands)

    Tuijn, P.

    1969-01-01

    The attention is called to the presence in the “Artis-Bibliotheek” of two representations of the extinct Alectroenas nitidissima and the only known description of its voice. Furthermore two pendrawings, found in a ship’s journal dating from 1601—1603 and very probably representing the same species,

  6. Manipulating pre-feed, density of reinforcement, and extinction produces disruption in the Location variation of a temporal discrimination task in pigeons.

    Science.gov (United States)

    McClure, Erin A; Saulsgiver, Kathryn A; Wynne, Clive D L

    2009-09-01

    When pharmacological and non-pharmacological agents are used to disrupt temporal discrimination, two major findings have emerged in the literature. One result reveals lateral shifts of the psychophysical curve for time due to disruptors, while the other is a decrease in accuracy for classifying short and long intervals and a flattening of the psychophysical curve. These results represent a discrepancy within the timing literature that requires clarification. The current study determined the effects of pre-feed, increased density of reinforcement during session, and extinction on the Location variation of a temporal discrimination procedure. The results showed that extinction and pre-feed (at higher levels), when presented in an acute fashion, led to right-ward shifts in the psychophysical curve. Our results, when compared to similar studies in the literature, suggest that lateral shifts are more likely to be found due to disruptors when the Location variation is being used and when procedures are less complicated.

  7. From dinosaurs to dodos: who could and should we de-extinct?

    Directory of Open Access Journals (Sweden)

    Kate Elizabeth Jones

    2014-03-01

    Full Text Available Reviving extinct species with new synthetic biology tools is as exciting an idea as it is controversial. Genomic manipulation of extinct species’ close relatives and/or cloning suitably preserved cells are the two main ways synthetic biology could be used to revive species. Discussions of where to target initial revival efforts have focused on species’ charisma (e.g. Woolly mammoth, Passenger pigeon with less emphasis on feasibility or the ecological, ethical and legal considerations. Here I discuss who we could and should de-extinct, focussing on these latter criteria. Given the current devastating anthropogenic pressures on biodiversity, I suggest that a better use of de-extinction technologies would be to focus them on preventing species extinctions by restoring populations of critically endangered species. For example, this could be through increasing population numbers through cloning or genomic manipulation to better enable susceptible species to adapt to global change or by restoring genetic diversity by reviving extinct sub-species (e.g. Quagga, Barbary lion. This idea circumvents many of the criticisms of de-extinction from conservationists, whilst retaining public interest in de-extinction.

  8. Perceptual grouping in pigeons.

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    Nagasaka, Yasuo; Hori, Koji; Osada, Yoshihisa

    2005-01-01

    Animal studies reveal that many species perceive partially occluded objects in the same way as do humans. Pigeons have been a notable exception. We re-investigated this anomaly of pigeon perception using a different approach from previous studies. With our method, we show that pigeons perceive occluded objects in the same manner as do other species. In addition, we report that pigeons can recognize perceptually transparent surfaces when the effect is induced by the same perceptual mechanisms as occlusion. These results give behavioral evidence that the perception of both occlusion and transparency is a common visual function shared by pigeons and humans, despite the structural differences between their visual systems.

  9. Viral infections in pigeons.

    Science.gov (United States)

    Marlier, D; Vindevogel, H

    2006-07-01

    This review provides a current update on the major viral diseases of the domestic pigeon (Columba livia domestica), based on scientific reports and clinical experience. Paramyxovirus 1, adenovirus, rotavirus, herpesvirus 1, poxvirus and circovirus infections are described according to common clinical signs and target tissues. Since pigeons are sometimes treated as if they were poultry, the review also summarises the common viral infections of poultry for which pigeons are considered resistant. It is hoped that the review will provide a useful reference for veterinarians and others and offer advice on the diagnosis, treatment and prevention of the major infectious diseases of pigeons.

  10. Complete mitochondrial genomes of eleven extinct or possibly extinct bird species.

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    Anmarkrud, Jarl A; Lifjeld, Jan T

    2017-03-01

    Natural history museum collections represent a vast source of ancient and historical DNA samples from extinct taxa that can be utilized by high-throughput sequencing tools to reveal novel genetic and phylogenetic information about them. Here, we report on the successful sequencing of complete mitochondrial genome sequences (mitogenomes) from eleven extinct bird species, using de novo assembly of short sequences derived from toepad samples of degraded DNA from museum specimens. For two species (the Passenger Pigeon Ectopistes migratorius and the South Island Piopio Turnagra capensis), whole mitogenomes were already available from recent studies, whereas for five others (the Great Auk Pinguinis impennis, the Imperial Woodpecker Campehilus imperialis, the Huia Heteralocha acutirostris, the Kauai Oo Moho braccathus and the South Island Kokako Callaeas cinereus), there were partial mitochondrial sequences available for comparison. For all seven species, we found sequence similarities of >98%. For the remaining four species (the Kamao Myadestes myadestinus, the Paradise Parrot Psephotellus pulcherrimus, the Ou Psittirostra psittacea and the Lesser Akialoa Akialoa obscura), there was no sequence information available for comparison, so we conducted blast searches and phylogenetic analyses to determine their phylogenetic positions and identify their closest extant relatives. These mitogenomes will be valuable for future analyses of avian phylogenetics and illustrate the importance of museum collections as repositories for genomics resources. © 2016 John Wiley & Sons Ltd.

  11. Echoic memory in pigeons

    NARCIS (Netherlands)

    C. Kretzschmar; T. Kalenscher; O. Güntürkün; C. Kaernbach

    2008-01-01

    It is unknown whether birds are able to retain the memory of purely sensory auditory information such as white noise over an extended period of time. In a Pavlovian heart rate conditioning paradigm, four pigeons were trained to associate a mild electric shock with periodic random waveforms, and no s

  12. Human infestation by pigeon fleas (Ceratophyllus columbae) from feral pigeons.

    NARCIS (Netherlands)

    Haag-Wackernagel, D; Spiewak, R.W.

    2004-01-01

    The report concerns a married couple who were repeatedly invaded by pigeon fleas (Ceratophyllus columbae) over a period of 2 months. The source of the fleas was a pair of breeding feral pigeons (Columba livia). The birds' nest was located in the attic immediately above the couple's apartment, and th

  13. [Pigeon sport and animal rights].

    Science.gov (United States)

    Warzecha, M

    2007-03-01

    To begin, a short overview of the organization and the realization of the racing pigeon sport. Some physiological facts, relevant to racing pigeons, will be touched on. Lastly, a focus on the flights, their completion and the problems involved with the, in some cases, high number of lost pigeons. The German Club of Pigeon Breeders, has made improvements but, it is certainly not enough. The topic of "City Pigeons" will be briefed. The final part deals with pertinent animal rights issues, causes of mishaps, and some rectifying possibilities, which are available to the government veterinarian. Special emphasis will be placed on the international uniformity of this issue. The lecture should prove that there is a need for every government veterinarian to become actively involved, because the described problematic has a major effect on a very large number of animals.

  14. Experimental infection of domestic pigeons with pigeon circovirus.

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    Schmidt, Volker; Schlömer, Julian; Lüken, Caroline; Johne, Reimar; Biere, Barbara; Müller, Hermann; Krautwald-Junghanns, Maria-Elisabeth

    2008-09-01

    Pigeon circovirus (PiCV) infection and young pigeon disease syndrome (YPDS), associated with high morbidity and mortality, have been recognized in young racing pigeons from large portions of Central Europe. There exist a number of data indicating that YPDS is a consequence of PiCV infection and subsequent immunosuppression. In order to prove PiCV to be one of the crucial factors of YPDS, an experimental infection with PiCV was performed under controlled conditions. Twenty-four domestic pigeons (Columba livia forma domestica) were divided into two groups with 12 pigeons each; an infection group and a control group. All birds were between their fourth to eighth week of life. Pigeons in the infection group were infected both intramuscularly and orally with PiCV purified from naturally infected birds, while pigeons in the control group received a placebo. To test a possible influence of the PiCV infection on the immune system, the animals in both groups were vaccinated simultaneously, on the same day, against PMV-1 (Lasovac plus, IDT, Dessau-Tornau, Germany). Weekly virologic testing showed a viraemic period, and excretion of the infection virus, in pigeons in the infection group. Replication of PiCV could be proved on the basis of histologic findings of multiglobular inclusion bodies, mainly observed in macrophages of the bursa of Fabricius. A PiCV, genetically distinct from the experimental virus, was detected in the control group by polymerase chain reaction (PCR) testing, but any histologic findings comparable to the infection group were absent. None of the pigeons revealed clinical signs of illness, or hints that immunosuppression had occurred, regardless of their group. The absence of stressful conditions, considered as a trigger for the development of YPDS, may be responsible for the failure of disease reproduction in our infection model.

  15. Estímulo discriminativo de extinção produzido por respostas de observação em pombos Discriminative stimulus of extinction produced by observing responses in pigeons

    Directory of Open Access Journals (Sweden)

    Gerson Yukio Tomanari

    2011-01-01

    Full Text Available Pombos privados de comida foram expostos a tentativas que podiam terminar com ou sem a apresentação de comida independentemente de qualquer resposta. Durante uma tentativa, bicadas podiam mudar a cor do disco de resposta de branco para verde (S+ ou vermelho (S- a depender do acionamento (ou não do comedouro. Em linha de base, bicadas produziam ambas as cores em intervalos médios variáveis de 15 s. Em duas condições experimentais distintas, tandem VI DRH foi empregado na produção, ora de S+, ora de S-. Resultados mostraram que o esquema tandem levou a uma diminuição geral na freqüência de estímulos discriminativos produzidos, marcadamente na de S+, mas não na de S-. Esses dados fornecem suporte para o modelo de reforçamento condicionado baseado na redução da incerteza.Food-deprived pigeons were given a series of trials in which half ended with response- independent food presentation and half without it. During a trial, pecking the key could change its color from white to green (S+ or red (S-, depending on whether food was programmed or not. In baseline conditions, pecks produced both stimuli (colors on a 15-s variable-interval schedule. In two different conditions, tandem VI DRH was applied to produce either S+ or S-. Results showed that the tandem contingency resulted in a general decrease in the discriminative stimulus production, markedly to S+, but not to S-. The findings are consistent with the uncertainty-reduction model of conditioned reinforcement.

  16. Passengers, Information, and Disruptions

    NARCIS (Netherlands)

    E. van der Hurk (Evelien)

    2015-01-01

    markdownabstract__Abstract__ Passengers traveling in public transport generate a detailed digital track record of their journey through using automated fare collection systems and carrying mobile devices. This information on passenger behavior has only recently become available to public transport

  17. Maladaptive "gambling" by pigeons.

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    Zentall, Thomas R

    2011-05-01

    When humans buy a lottery ticket or gamble at a casino they are engaging in an activity that on average leads to a loss of money. Although animals are purported to engage in optimal foraging behavior, similar sub-optimal behavior can be found in pigeons. They show a preference for an alternative that is associated with a low probability of reinforcement (e.g., one that is followed by a red hue on 20% of the trials and then reinforcement or by a green hue on 80% of the trials and then the absence of reinforcement) over an alternative that is associated with a higher probability of reinforcement (e.g., blue or yellow each of which is followed by reinforcement 50% of the time). This effect appears to result from the strong conditioned reinforcement associated with the stimulus that is always followed by reinforcement. Surprisingly, although it is experienced four times as much, the stimulus that is never followed by reinforcement does not appear to result in significant conditioned inhibition (perhaps due to the absence of observing behavior). Similarly, human gamblers tend to overvalue wins and undervalue losses. Thus, this animal model may provide a useful analog to human gambling behavior, one that is free from the influence of human culture, language, social reinforcement, and other experiential biases that may influence human gambling behavior.

  18. Coordinated Behaviour in Pigeon Flocks.

    Directory of Open Access Journals (Sweden)

    Makoto Yomosa

    Full Text Available We analysed pigeon flock flights using GPS trajectory data to reveal the most important kinematic aspects of flocking behaviour. We quantitatively investigated the internal motion of the flock based on pairwise statistics and found the following general relationships in all datasets: i the temporal order of decisions characterised by the delay between directional changes is strictly related to the spatial order characterised by the longitudinal relative position within the flock; ii during circling motion, pigeons use a mixture of two idealised and fundamentally different turning strategies, namely, parallel-path and equal-radius type turning. While pigeons tend to maintain their relative position within the flock on average, as in the parallel-path approximation, those who turn later also get behind as in the equal-radius case. Equal-radius type turning also tends to be expressed more during smaller radius turns.

  19. Phylogeny and biogeography of the imperial pigeons (Aves: Columbidae) in the Pacific Ocean.

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    Cibois, Alice; Thibault, Jean-Claude; Bonillo, Céline; Filardi, Christopher E; Pasquet, Eric

    2017-05-01

    We reconstruct the phylogeny of imperial pigeons (genus Ducula) using mitochondrial and nuclear sequence data. We evaluate the most likely biogeographic scenario for the evolution of this group that colonized many islands of the Pacific Ocean. The divergence time analysis suggests that the basal divergences within Ducula occurred more recently than in the fruit doves (genus Ptilinopus), a group that is also well diversified in Oceania. The imperial pigeons colonized the Melanesian region several times independently, and the diversification within this region led to several species in sympatry, in particular in the Bismarck archipelago. Central Polynesia was also colonized several times, first by a lineage during the Miocene that led to the large D. latrans, sister to the New Caledonian endemic D. goliath, then more recently by the widespread D. pacifica, during the Pleistocene. The phylogenetic pattern obtained with the extant Ducula species showed that the Eastern Polynesian endemics do not form a monophyletic group, with the Pacific Imperial Pigeon D. pacifica sister species with good support to the Polynesian Imperial Pigeon D. aurorae. However, the impact of recent anthropic extinctions has been important for the imperial pigeons, more than for the smaller fruit doves, suggesting that several Ducula lineages might be missing today. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Shape from Shading in Pigeons

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    Cook, Robert G.; Qadri, Muhammad A. J.; Kieres, Art; Commons-Miller, Nicholas

    2012-01-01

    Light is the origin of vision. The pattern of shading reflected from object surfaces is one of several optical features that provide fundamental information about shape and surface orientation. To understand how surface and object shading is processed by birds, six pigeons were tested with differentially illuminated convex and concave curved…

  1. Pigeon homing from unfamiliar areas

    OpenAIRE

    Wallraff, Hans G

    2014-01-01

    The conclusion that pigeons and other birds can find their way home from unfamiliar areas by means of olfactory signals is well based on a variety of experiments and supporting investigations of the chemical atmosphere. Here I argue that alternative concepts proposing other sources of geopositional information are disproved by experimental findings or, at least, are not experimentally supported and hardly realistic.

  2. Passenger Information System Simulation

    OpenAIRE

    Botha, Louis

    2015-01-01

    This thesis goes through the development process of a Passenger Information System simulator for a customer to test their route information databases on before distributing these to the rolling stock. The paper starts by describing the basic components and devices of a Mitron passenger information system and the purpose of the passenger information system simulator ordered by the customer. The paper continues by describing the initial design that was offered to the customer. The 11 ma...

  3. Divers of Passenger Demand

    OpenAIRE

    Wittmer, Andreas

    2011-01-01

    -Overview drivers of passenger demand -Driver 1: Economic growth in developing countries -Driver 2: International business travel in developed countries -Driver 3: International leisure travel in developed countries

  4. Pigeons home faster through polluted air

    OpenAIRE

    Zhongqiu Li; Franck Courchamp; Daniel T. Blumstein

    2016-01-01

    Air pollution, especially haze pollution, is creating health issues for both humans and other animals. However, remarkably little is known about how animals behaviourally respond to air pollution. We used multiple linear regression to analyse 415 pigeon races in the North China Plain, an area with considerable air pollution, and found that while the proportion of pigeons successfully homed was not influenced by air pollution, pigeons homed faster when the air was especially polluted. Our resu...

  5. Fast Passenger Tracks Network

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    China’s fast passenger tracks network consists of four parts:express rail- way with speeds between 300km/h and 350 kin/h,passenger rail lines with speeds between 200 km/h and 250 km/h,intercity high-speed railways that run

  6. Rail passengers rights

    Directory of Open Access Journals (Sweden)

    Đurđev Dušanka J.

    2016-01-01

    Full Text Available The legal framework of rail passengers rights is set out in a combination of international and European law: an international measure, the rather unwieldy Uniform Rules concerning the Contract for International Carriage of Passengers and Luggage by Rail, forming part of the Convention concerning International Carriage by Rail of 9 May 1980 (as amended by the Vilnius Protocol of 3 June 1999 ['CIV'], lays down a basic framework which is then fleshed out by more recent EU legislation, Regulation (EC No 1371/2007 on Rail Passengers ' Rights and Obligations. Regulation 1371/2007/EC on rail passenger rights and obligations sets out minimum quality standards that have to be guaranteed to all passengers on all lines. .

  7. Rethinking Extinction.

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    Dunsmoor, Joseph E; Niv, Yael; Daw, Nathaniel; Phelps, Elizabeth A

    2015-10-07

    Extinction serves as the leading theoretical framework and experimental model to describe how learned behaviors diminish through absence of anticipated reinforcement. In the past decade, extinction has moved beyond the realm of associative learning theory and behavioral experimentation in animals and has become a topic of considerable interest in the neuroscience of learning, memory, and emotion. Here, we review research and theories of extinction, both as a learning process and as a behavioral technique, and consider whether traditional understandings warrant a re-examination. We discuss the neurobiology, cognitive factors, and major computational theories, and revisit the predominant view that extinction results in new learning that interferes with expression of the original memory. Additionally, we reconsider the limitations of extinction as a technique to prevent the relapse of maladaptive behavior and discuss novel approaches, informed by contemporary theoretical advances, that augment traditional extinction methods to target and potentially alter maladaptive memories. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Rethinking Extinction

    OpenAIRE

    Dunsmoor, Joseph E.; Niv, Yael; Daw, Nathaniel; Phelps, Elizabeth A.

    2015-01-01

    Extinction serves as the leading theoretical framework and experimental model to describe how learned behaviors diminish through absence of anticipated reinforcement. In the past decade, extinction has moved beyond the realm of associative learning theory and behavioral experimentation in animals and has become a topic of considerable interest in the neuroscience of learning, memory, and emotion. Here, we review research and theories of extinction, both as a learning process and as a behavior...

  9. Pigeons' Discounting of Probabilistic and Delayed Reinforcers

    Science.gov (United States)

    Green, Leonard; Myerson, Joel; Calvert, Amanda L.

    2010-01-01

    Pigeons' discounting of probabilistic and delayed food reinforcers was studied using adjusting-amount procedures. In the probability discounting conditions, pigeons chose between an adjusting number of food pellets contingent on a single key peck and a larger, fixed number of pellets contingent on completion of a variable-ratio schedule. In the…

  10. Yield potential of pigeon pea cultivars

    Science.gov (United States)

    Yield potential of twelve vegetable pigeon pea (Cajanus cajun) cultivars was evaluated at two locations in eastern Kenya during 2012 and 2013 cropping years. Pigeon pea pod numbers, seeds per pod, seed mass, grain yield and shelling percentage were quantified in three replicated plots, arranged in a...

  11. Photoreceptor cell dysplasia in two Tippler pigeons.

    Science.gov (United States)

    Moore, P A; Munnell, J F; Martin, C L; Prasse, K W; Carmichael, K P

    2004-01-01

    Two 12-week-old Tippler pigeons were evaluated for ocular abnormalities associated with congenital blindness. The pigeons were emaciated and blind. Biomicroscopy and direct and indirect ophthalmoscopy findings of the Tippler pigeons were normal with the exception of partially dilated pupils at rest. Scotopic (blue stimuli) and photopic monocular electroretinograms were extinguished in the blind Tippler pigeons. Histological and electron microscopy studies revealed reduced numbers of rods and cones, and an absence of the double cone complex. The photoreceptor cells' outer segments were absent, and the inner segments were short and broad. The number of cell nuclei in the outer and inner nuclear layers was decreased, and the internal and external plexiform layers were reduced in width. Photoreceptor cell endfeet with developing synaptic ribbons were present in the external plexiform layer. Inflammatory cell and subretinal debris was not seen. The electroretinographic, histopathological, and ultrastructural findings of the blind Tippler pigeons support the diagnosis of a photoreceptor cell dysplasia.

  12. Extinction as discrimination: the molar view.

    Science.gov (United States)

    Baum, William M

    2012-05-01

    The traditional molecular view of behavior explains extinction as the dissipation or inhibition of strength, formerly built up by contiguous reinforcement. In obstinate opposition to this explanation was the partial-reinforcement extinction effect: a partially reinforced response extinguishes more slowly than a continuously reinforced response. It suggests instead that extinction is discrimination. Four pigeons were exposed to daily sessions in which a variable period of food delivery, produced by pecking on a variable-interval schedule, was followed by extinction. The rate of food delivery was varied over a wide range across conditions. Varying the amount of food per delivery inversely with rate of delivery kept response rate from varying excessively. The results confirmed and extended the partial-reinforcement effect; persistence of pecking and time to extinction were inversely related to rate of obtaining food. The results support the molar view of extinction, not as loss of strength of a particular discrete response, but as a transition from one allocation of time among activities to another. Although molecular theories dismiss discrimination due to repeated training and extinction as an impurity or complication, repeated cycles of availability and privation are probably typical of the environment in which most vertebrate species evolved.

  13. Folds--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the folds for the geologic and geomorphic map of the Offshore Pigeon Point map area, California. The vector data file is...

  14. Faults--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the faults for the geologic and geomorphic map of the Offshore Pigeon Point map area, California. The vector data file is...

  15. Folds--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the folds for the geologic and geomorphic map of the Offshore Pigeon Point map area, California. The vector data file is...

  16. Bathymetry--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetry and shaded-relief maps of Offshore Pigeon Point, California. The raster data file is included in...

  17. Bathymetry Hillshade--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetry and shaded-relief maps of Offshore Pigeon Point, California. The raster data file is included in...

  18. Bathymetry--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetry and shaded-relief maps of Offshore Pigeon Point, California. The raster data file is included in...

  19. Contours--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetric contours for several seafloor maps of the Offshore Pigeon Point map area, California. The vector data file is...

  20. Habitat--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the habitat map of the seafloor of the Offshore of Pigeon Point map area, California. The vector data file is included in...

  1. Bathymetry Hillshade--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetry and shaded-relief maps of Offshore Pigeon Point, California. The raster data file is included in...

  2. Faults--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the faults for the geologic and geomorphic map of the Offshore Pigeon Point map area, California. The vector data file is...

  3. Passive immunization of pigeons against trichomoniasis

    Science.gov (United States)

    Kocan, R.M.

    1970-01-01

    Nonimmune homing pigeons Columba livia were infected with the Jones' Barn strain of Trichomonas gallinae and subsequently transfused with plasma from acute or chronically infected pigeons harboring one of 3 different strains of T. gallinae. The transfusions were either a single 2 mi dose given one day after inoculation or three 1 ml doses given 0, 5, and 10 days after inoculation. Plasma from pigeons harboring any of the 3 strains was capable of passively immunizing nonimmune birds. All birds which were immunized with plasma from infected pigeons survived until killed at the end of the test period and no visceral lesions were found on necropsy but trichomonads were present in the oropharynx. All controls (untreated or transfused with normal plasma) died of visceral trichomoniasis. Immune plasma produced some lysis of trichomonads in vitro, and inhibition of motility and vacuolization occurred in some of the non-lysed organisms. The overall lytic activity in vitro affected less than 10% of the suspended trichomonads.

  4. Habitat--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the habitat map of the seafloor of the Offshore of Pigeon Point map area, California. The vector data file is included in...

  5. Effectiveness of Gel Repellents on Feral Pigeons

    Directory of Open Access Journals (Sweden)

    Birte Stock

    2013-12-01

    Full Text Available Millions of feral pigeons (Columba livia live in close association with the human population in our cities. They pose serious health risks to humans and lead to high economic loss due to damage caused to buildings. Consequently, house owners and city authorities are not willing to allow pigeons on their buildings. While various avian repellents are regularly introduced onto the market, scientific proof of efficacy is lacking. This study aimed at testing the effectiveness of two avian gel repellents and additionally examined their application from animal welfare standpoint. The gels used an alleged tactile or visual aversion of the birds, reinforced by additional sensory cues. We mounted experimental shelves with the installed repellents in a pigeon loft and observed the behavior of free-living feral pigeons towards the systems. Both gels showed a restricted, transient repellent effect, but failed to prove the claimed complete effectiveness. Additionally, the gels’ adhesive effect remains doubtful in view of animal welfare because gluing of plumage presents a risk to feral pigeons and also to other non-target birds. This study infers that both gels lack the promised complete efficacy, conflict with animal welfare concerns and are therefore not suitable for feral pigeon management in urban areas.

  6. Suboptimal choice behavior by pigeons.

    Science.gov (United States)

    Stagner, Jessica P; Zentall, Thomas R

    2010-06-01

    Contrary to the law of effect and optimal foraging theory, pigeons show suboptimal choice behavior by choosing an alternative that provides 20% reinforcement over another that provides 50% reinforcement. They choose the 20% reinforcement alternative--in which 20% of the time, that choice results in a stimulus that always predicts reinforcement, and 80% of the time, it results in another stimulus that predicts its absence--rather than the 50% reinforcement alternative, which results in one of two stimuli, each of which predicts reinforcement 50% of the time. This choice behavior may be related to suboptimal human monetary gambling behavior, because in both cases, the organism overemphasizes the infrequent occurrence of the winning event and underemphasizes the more frequent occurrence of the losing event.

  7. [The relation between resistance to change and preference in pigeons with concurrent chained schedules].

    Science.gov (United States)

    Igaki, T; Sakagami, T

    2001-06-01

    Two experiments were conducted to investigate the relation between resistance to change and preference. Four pigeons responded in concurrent chained schedules in which variable-interval (VI) 60-s schedules were arranged in the initial link. In Experiment 1, VI and fixed-interval (FI) schedules of equal mean reinforcement rates were arranged in the terminal link. Response rates were higher in the initial link leading to VI terminal link. Under the prefeeding test, the initial-link response rates leading to VI terminal link were more resistant to change than were those leading to FI terminal link, but under the extinction test there were no consistent differences between the two initial-link response rates. In Experiment 2, FI value of the terminal link was manipulated so that pigeons maintained approximately equal responding in the initial link. The two initial-link response rates showed equal resistance to change under the prefeeding and extinction tests. Thus, the data suggest that although the use of extinction as a manipulation to study resistance to change is questioned, resistance to change and preference are different measures of a single object.

  8. Experience with dynamic reinforcement rates decreases resistance to extinction.

    Science.gov (United States)

    Craig, Andrew R; Shahan, Timothy A

    2016-03-01

    The ability of organisms to detect reinforcer-rate changes in choice preparations is positively related to two factors: the magnitude of the change in rate and the frequency with which rates change. Gallistel (2012) suggested similar rate-detection processes are responsible for decreases in responding during operant extinction. Although effects of magnitude of change in reinforcer rate on resistance to extinction are well known (e.g., the partial-reinforcement-extinction effect), effects of frequency of changes in rate prior to extinction are unknown. Thus, the present experiments examined whether frequency of changes in baseline reinforcer rates impacts resistance to extinction. Pigeons pecked keys for variable-interval food under conditions where reinforcer rates were stable and where they changed within and between sessions. Overall reinforcer rates between conditions were controlled. In Experiment 1, resistance to extinction was lower following exposure to dynamic reinforcement schedules than to static schedules. Experiment 2 showed that resistance to presession feeding, a disruptor that should not involve change-detection processes, was unaffected by baseline-schedule dynamics. These findings are consistent with the suggestion that change detection contributes to extinction. We discuss implications of change-detection processes for extinction of simple and discriminated operant behavior and relate these processes to the behavioral-momentum based approach to understanding extinction.

  9. Avermectin induced autophagy in pigeon spleen tissues.

    Science.gov (United States)

    Liu, Ci; Zhao, Yanbing; Chen, Lijie; Zhang, Ziwei; Li, Ming; Li, Shu

    2015-12-05

    The level of autophagy is considered as an indicator for monitoring the toxic impact of pesticide exposure. Avermectin (AVM), a widely used insecticide, has immunotoxic effects on the pigeon spleen. The aim of this study was to investigate the status of autophagy and the expression levels of microtubule-associated protein1 light chain 3 (LC3), beclin-1, dynein, autophagy associated gene (Atg) 4B, Atg5, target of rapamycin complex 1 (TORC1) and target of rapamycin complex 2 (TORC2) in AVM-treated pigeon spleens. Eighty two-month-old pigeons were randomly divided into four groups: a control group, a low-dose group, a medium-dose group and a high-dose group, which were fed a basal diet spiked with 0, 20, 40 and 60 mg AVM/kg diet, respectively. Microscopic cellular morphology revealed a significant increase in autophagic structures in the AVM-treated groups. The expression of LC3, beclin-1, dynein, Atg4B and Atg5 increased, while mRNA levels of TORC1 and TORC2 were decreased in the AVM-treated groups relative to the control groups at 30, 60 and 90 days in the pigeon spleen. These results indicated that AVM exposure could up-regulate the level of autophagy in a dose-time-dependent manner in the pigeon spleen.

  10. 14 CFR 91.1035 - Passenger awareness.

    Science.gov (United States)

    2010-01-01

    ... require passenger compliance with lighted passenger information signs and no smoking placards, prohibit...) Use of safety belts, shoulder harnesses, and child restraint systems: Each passenger must be briefed... appropriate, that the regulations require passenger compliance with the lighted passenger information sign and...

  11. Prevalence of pigeon circovirus infections in feral pigeons in Ljubljana, Slovenia.

    Science.gov (United States)

    Krapez, Uros; Slavec, Brigita; Steyer, Adela Fratnik; Pintaric, Stefan; Dobeic, Martin; Rojs, Olga Zorman; Dovc, Alenka

    2012-06-01

    Pigeon circovirus (PiCV) was detected by real-time PCR in cloacal swabs, pharyngeal swabs, and serum samples taken from 74 feral pigeons (Columba livia var. domestica) that were caught at various locations in the city of Ljubljana, Slovenia. PiCV infections were detected in the majority of the tested birds. The highest (74.3%) detection rate was observed in the cloacal swabs and the lowest (31.1%) in serum samples. PiCV DNA was more readily detected in the cloacal swabs, pharyngeal swabs, and serum samples of birds younger than 1 yr. Molecular analysis of partial open reading frame V1 sequences showed that PiCV strains detected in feral pigeons share high nucleotide and amino acid sequence identities with PiCV strains detected in ornamental, racing, meat, and feral pigeons.

  12. Superstitious responding and reinforcement rate under concurrent variable-interval extinction schedules.

    Science.gov (United States)

    Doughty, A H.; Shahan, T A.; Lattal, K A.

    2001-04-26

    To examine superstitious responding, four pigeons key pecked under multiple concurrent variable-interval 45 s variable-interval 90 s concurrent variable-interval 90 s variable-interval 180 s schedules in the absence of a changeover delay. The two variable-interval 90 s schedules then were replaced by extinction, and key-peck responding during extinction was examined as a function of the prevailing reinforcement rate. During the first several sessions, extinction-key responding was maintained closer to baseline levels in the presence of the higher reinforcement rate, and this effect dissipated or even reversed with continued exposure to extinction. Although extinction-key responding generally decreased to near-zero levels after several sessions, in a few instances, it continued for 30 and 45 sessions. These results demonstrate how concurrent variable-interval extinction schedules can be used to investigate what often has been labeled superstitious responding.

  13. Interstellar Extinction

    Science.gov (United States)

    Gontcharov, G. A.

    2016-12-01

    This review describes our current understanding of interstellar extinction. This differ substantially from the ideas of the 20th century. With infrared surveys of hundreds of millions of stars over the entire sky, such as 2MASS, SPITZER-IRAC, and WISE, we have looked at the densest and most rarefied regions of the interstellar medium at distances of a few kpc from the Sun. Observations at infrared and microwave wavelengths, where the bulk of the interstellar dust absorbs and radiates, have brought us closer to an understanding of the distribution of the dust particles on scales of the Galaxy and the universe. We are in the midst of a scientific revolution in our understanding of the interstellar medium and dust. Progress in, and the key results of, this revolution are still difficult to predict. Nevertheless, (a) a physically justified model has been developed for the spatial distribution of absorbing material over the nearest few kiloparsecs, including the Gould belt as a dust container, which gives an accurate estimate of the extinction for any object just by its galactic coordinates. It is also clear that (b) the interstellar medium contains roughly half the mass of matter in the galactic vicinity of the solar system (the other half is made up of stars, their remnants, and dark matter) and (c) the interstellar medium and, especially, dust, differ substantially in different regions of space and deep space cannot be understood by only studying near space.

  14. Spatial context learning in pigeons (Columba livia).

    Science.gov (United States)

    Gibson, Brett M; Leber, Andrew B; Mehlman, Max L

    2015-10-01

    In a seminal paper in the cognitive sciences, Chun and Jiang (1998) described the contextual cueing paradigm in which they used artificial stimuli and showed that people became faster to locate a target when the background predicted the location of a target compared to when it did not. Here we examined contextual cueing in pigeons for the first time using artificial stimuli and procedures similar to those of Chun and Jiang. In the first test, we had pigeons search for a target among a display of seven distractors; during one condition, the position of the distractors predicted the location of the target, and in the second condition, there was no relationship between the two. In a second test, we presented the pigeons with the predictive displays from Test 1 and a second set of displays that also predicted the location of a target to see if learning about one set of predictive backgrounds disrupted learning about a second set. The pigeons were quick to acquire context-based knowledge and retain that information when faced with additional contexts. The results suggest that contextual cueing can occur for a variety of stimuli in nonhuman animals and that it may be a common mechanism for processing visual information across a wide variety of species.

  15. Getting passengers out : evacuation behaviours

    NARCIS (Netherlands)

    Boer, L.C.

    2003-01-01

    When disaster strikes, mass transportation means mass evacuation. The issue is especially urgent if, despite precautions, a train comes to a stop in a tunnel and there is a fire. Adequate behaviour of passengers is a major success factor of an evacuation. Passengers should replace their original (tr

  16. Intermodal Passenger Connectivity Database - Raw Data

    Data.gov (United States)

    Department of Transportation — The Intermodal Passenger Connectivity Database (IPCD) is a nationwide data table of passenger transportation terminals, with data on the availability of connections...

  17. Effect of a commercial paratyphus vaccine on the development of pigeon circovirus infection in young pigeons (Columba livia domestica).

    Science.gov (United States)

    Duchatel, Jean Pierre; Jauniaux, Thierry; Smyth, Joan; Habsch, Isabelle; de Bournonville, Marc; Losson, Bertrand; Todd, Danny

    2010-06-01

    Infection with pigeon circovirus (PiCV) has been associated with young pigeon disease syndrome (YPDS), which is considered to be a multifactorial disease. The factors that determine whether birds succumb to clinical disease are not known. To evaluate the potential effect of vaccination with a commercial paratyphus vaccine on the progression of PiCV infection in young pigeons, forty 6-week-old pigeons naturally infected with PiCV were randomly assigned to two equal groups. The pigeons of one group were vaccinated at 6 and 9 weeks of age, and pigeons of the second group were unvaccinated controls. Cloacal swab and blood samples collected from all the birds were tested for PiCV by polymerase chain reaction (PCR) analysis. Three weeks after the second vaccination, all pigeons were euthanatized, and tissues were collected for PiCV PCR analysis and histopathologic evaluation. No significant difference in the number of PCR-positive cloacal swab and blood samples was found between the vaccinated and control pigeons. Positive PCR results in tissue samples also were not significantly different between the groups, with 18 positive samples in vaccinated birds (90%) and 16 in control birds (80%). Characteristic botryoid inclusions were detected in more vaccinated than control pigeons, but this difference was not significant. In this study, vaccination with a commercial paratyphus vaccine was not a risk factor for development of young pigeon disease syndrome.

  18. The EU Passenger Name Record (PNR) System and Human Rights : Transferring Passenger Data or Passenger Freedom?

    NARCIS (Netherlands)

    Brouwer, E.R.

    2009-01-01

    The European Commission presented the ‘EU Passenger Name Record (PNR) system’ in 2007 as a tool in the fight against terrorism and organised crime. One of the proposed instruments of this system is the Framework Decision on the use of PNR, which provides for the storage and exchange of passenger dat

  19. Physical restraint produces rapid acquisition of the pigeon's key peck

    Science.gov (United States)

    Locurto, C. M.; Travers, Tania; Terrace, H. S.; Gibbon, John

    1980-01-01

    The acquisition and maintenance of autoshaped key pecking in pigeons was studied as a function of intertrial interval. At each of six intervals, which ranged from 12 seconds to 384 seconds, four pigeons were physically restrained during training while four other pigeons were not restrained. Restrained subjects acquired key pecking faster and with less intragroup variability at each interval. The effects of restraint were specific to acquisition and were not evident in maintained responding after five postacquisition sessions. PMID:16812175

  20. The dynamics of conditioning and extinction.

    Science.gov (United States)

    Killeen, Peter R; Sanabria, Federico; Dolgov, Igor

    2009-10-01

    Pigeons responded to intermittently reinforced classical conditioning trials with erratic bouts of responding to the conditioned stimulus. Responding depended on whether the prior trial contained a peck, food, or both. A linear persistence-learning model moved pigeons into and out of a response state, and a Weibull distribution for number of within-trial responses governed in-state pecking. Variations of trial and intertrial durations caused correlated changes in rate and probability of responding and in model parameters. A novel prediction--in the protracted absence of food, response rates can plateau above zero--was validated. The model predicted smooth acquisition functions when instantiated with the probability of food but a more accurate jagged learning curve when instantiated with trial-to-trial records of reinforcement. The Skinnerian parameter was dominant only when food could be accelerated or delayed by pecking. These experiments provide a framework for trial-by-trial accounts of conditioning and extinction that increases the information available from the data, permitting such accounts to comment more definitively on complex contemporary models of momentum and conditioning.

  1. Magnetoreception and its trigeminal mediation in the homing pigeon

    Science.gov (United States)

    Mora, Cordula V.; Davison, Michael; Martin Wild, J.; Walker, Michael M.

    2004-11-01

    Two conflicting hypotheses compete to explain how a homing pigeon can return to its loft over great distances. One proposes the use of atmospheric odours and the other the Earth's magnetic field in the `map' step of the `map and compass' hypothesis of pigeon homing. Although magnetic effects on pigeon orientation provide indirect evidence for a magnetic `map', numerous conditioning experiments have failed to demonstrate reproducible responses to magnetic fields by pigeons. This has led to suggestions that homing pigeons and other birds have no useful sensitivity to the Earth's magnetic field. Here we demonstrate that homing pigeons (Columba livia) can discriminate between the presence and absence of a magnetic anomaly in a conditioned choice experiment. This discrimination is impaired by attachment of a magnet to the cere, local anaesthesia of the upper beak area, and bilateral section of the ophthalmic branch of the trigeminal nerve, but not of the olfactory nerve. These results suggest that magnetoreception (probably magnetite-based) occurs in the upper beak area of the pigeon. Traditional methods of rendering pigeons anosmic might therefore cause simultaneous impairment of magnetoreception so that future orientation experiments will require independent evaluation of the pigeon's magnetic and olfactory systems.

  2. 14 CFR 91.517 - Passenger information.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Passenger information. 91.517 Section 91... Multiengine Airplanes and Fractional Ownership Program Aircraft § 91.517 Passenger information. (a) Except as... belts and when smoking is prohibited. (c) If passenger information signs are installed, no passenger...

  3. Robustness of flight leadership relations in pigeons

    CERN Document Server

    Flack, Andrea; Nagy, Máté; Vicsek, Tamás; Biro, Dora

    2016-01-01

    Collective animal movements produce spectacular natural phenomena that arise from simple local interactions among group members. Flocks of homing pigeons, Columba livia, provide a useful model for the study of collective motion and decision making. During homing flights, flock members are forced to resolve potentially divergent navigational preferences in order to stay together and benefit from flying in a group. Recent work has demonstrated that some individuals consistently contribute more to the movement decisions of the flock than others do, thereby generating stable hierarchical leader/follower networks. Yet, what attributes of a flying pigeon reliably predict leadership remains an open question. We examined the flexibility of an individual's hierarchical leadership rank (i.e. its ordinal position when flock members are ranked according to the average time differences with which they lead or follow others) as a function of changes in its navigational knowledge. We manipulated already established hierarch...

  4. "Good Passengers and Not Good Passengers:" Adolescent Drivers' Perceptions About Inattention and Peer Passengers.

    Science.gov (United States)

    McDonald, Catherine C; Sommers, Marilyn S

    The purpose of this qualitative focus group elicitation research study was to explore teen driver perceptions of peer passengers and driver inattention. We utilized focus groups for data collection and content analysis to analyze the data, both of which were guided by the theory of planned behavior. We conducted 7 focus groups with 30 teens, ages 16-18, licensed for ≤1year to examine attitudes, perceived behavioral control, and norms related to driving inattention and peer passengers. The sample was 50% male, mean age 17.39 (SD 0.52) with mean length of licensure 173.7days (SD 109.2). Three themes emerged: 1) "Good and not good" passengers; 2) Passengers and technology as harmful and helpful; and 3) The driver is in charge. While passengers can be a source of distraction, our participants also identified passenger behaviors that reduced risk, such as assistance with technology and guidance for directions. An understanding of teens' perceptions of peer passengers can contribute to the development of effective interventions targeting teen driver inattention. Nurses are well-positioned to contribute to these teen crash prevention efforts. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Context-dependent hierarchies in pigeons.

    Science.gov (United States)

    Nagy, Máté; Vásárhelyi, Gábor; Pettit, Benjamin; Roberts-Mariani, Isabella; Vicsek, Tamás; Biro, Dora

    2013-08-06

    Hierarchical organization is widespread in the societies of humans and other animals, both in social structure and in decision-making contexts. In the case of collective motion, the majority of case studies report that dominant individuals lead group movements, in agreement with the common conflation of the terms "dominance" and "leadership." From a theoretical perspective, if social relationships influence interactions during collective motion, then social structure could also affect leadership in large, swarm-like groups, such as fish shoals and bird flocks. Here we use computer-vision-based methods and miniature GPS tracking to study, respectively, social dominance and in-flight leader-follower relations in pigeons. In both types of behavior we find hierarchically structured networks of directed interactions. However, instead of being conflated, dominance and leadership hierarchies are completely independent of each other. Although dominance is an important aspect of variation among pigeons, correlated with aggression and access to food, our results imply that the stable leadership hierarchies in the air must be based on a different set of individual competences. In addition to confirming the existence of independent and context-specific hierarchies in pigeons, we succeed in setting out a robust, scalable method for the automated analysis of dominance relationships, and thus of social structure, applicable to many species. Our results, as well as our methods, will help to incorporate the broader context of animal social organization into the study of collective behavior.

  6. Method of stimulus combination impacts resistance to extinction.

    Science.gov (United States)

    Podlesnik, Christopher A; Bai, John Y H

    2015-07-01

    Reinforcing an alternative response in the presence of the stimuli governing a target response increases resistance to extinction of target responding, relative to training target responding on its own. Conversely, training alternative and target responses in the presence of different stimuli and combining those stimuli only decreases resistance to extinction of target responding, relative to target responding on its own. The present study assessed how different methods of combining discriminative stimuli influence resistance to extinction of responding in pigeons. As in previous studies, combining stimuli across different keys only decreased resistance to extinction of target responding relative to target responding on its own. In comparison, combining stimuli on the same key initially increased resistance to extinction of target responding, but repeated tests resulted in similar levels of responding as target responding with stimuli combined on separate keys. Moreover, greater overall reinforcement rates produced greater resistance to extinction with both methods of combining stimuli, consistent with behavioral momentum theory. These findings reveal several behavioral processes influence the outcome of combining stimuli--including perceptual processes, discriminative control by contingencies, response competition, and behavioral momentum.

  7. Resistance to extinction, generalization decrement, and conditioned reinforcement.

    Science.gov (United States)

    Dulaney, Alana E; Bell, Matthew C

    2008-06-01

    This study investigated generalization decrement during an extinction resistance-to-change test for pigeon key pecking using a two-component multiple schedule with equal variable-interval 3-min schedules and different reinforcer amounts (one component presented 2-s access to reinforcement and the other 8s). After establishing baseline responding, subjects were assigned to one of the two extinction conditions: hopper stimuli (hopper and hopper light were activated but no food was available) or Control (inactive hopper and hopper light). Responding in the 8-s component was more resistant to extinction than responding in the 2-s component, the hopper stimuli group was more resistant to extinction compared to the Control group, and an interaction between amount of reinforcement, extinction condition, and session block was present. This finding supports generalization decrement as a factor that influences resistance to extinction. Hopper-time data (the amount of time subjects spent with their heads in the hopper) were compared to resistance-to-change data in an investigation of the role of conditioned reinforcement on resistance to change.

  8. Information-seeking behavior: exploring metacognitive control in pigeons.

    Science.gov (United States)

    Castro, Leyre; Wasserman, Edward A

    2013-03-01

    Metacognitive control may occur if an organism seeks additional information when the available information for solving a problem is inadequate. Such information-seeking behavior has been documented in primates, but evidence of analogous behavior is less convincing in non-primates. In our study, we adopted a novel methodological approach. We presented pigeons with visual discriminations of varying levels of difficulty, and on special testing trials, we gave the birds the opportunity of making the discrimination easier. We initially trained pigeons on a discrimination between same and different visual arrays, each containing 12 items (low difficulty), 4 items (intermediate difficulty), or 2 items (high difficulty). We later provided an "Information" button that the pigeons could peck to increase the number of items in the arrays, thereby making the discrimination easier, plus a "Go" button which, when pecked, simply allowed the pigeons to proceed to their final discriminative response. Critically, our pigeons' choice of the "Information" button increased as the difficulty of the task increased. As well, some of our pigeons showed evidence of prompt and appropriate transfer of using the "Information" button to help them perform brand-new brightness and size discrimination tasks. Speculation as to the contents of pigeons' private mental states may be unwarranted, but our pigeons did objectively exhibit the kind of complex, flexible, and adaptive information-seeking behavior that is deemed to be involved in metacognitive control.

  9. Efficient Scheduling of Pigeons for a Constrained Delay Tolerant Application

    Directory of Open Access Journals (Sweden)

    Legand Burge

    2010-01-01

    Full Text Available Information collection in the disaster area is an important application of pigeon networks—a special type of delay tolerant networks (DTNs that borrows the ancient idea of using pigeons as the telecommunication method. The aim of this paper is to explore highly efficient scheduling strategies of pigeons for such applications. The upper bound of traffic that can be supported under the deadline constraints for the basic on-demand strategy is given through the analysis. Based on the analysis, a waiting-based packing strategy is introduced. Although the latter strategy could not change the maximum traffic rate that a pigeon can support, it improves the efficiency of a pigeon largely. The analytical results are verified by the simulations.

  10. Mechanisms of object recognition: what we have learned from pigeons.

    Science.gov (United States)

    Soto, Fabian A; Wasserman, Edward A

    2014-01-01

    Behavioral studies of object recognition in pigeons have been conducted for 50 years, yielding a large body of data. Recent work has been directed toward synthesizing this evidence and understanding the visual, associative, and cognitive mechanisms that are involved. The outcome is that pigeons are likely to be the non-primate species for which the computational mechanisms of object recognition are best understood. Here, we review this research and suggest that a core set of mechanisms for object recognition might be present in all vertebrates, including pigeons and people, making pigeons an excellent candidate model to study the neural mechanisms of object recognition. Behavioral and computational evidence suggests that error-driven learning participates in object category learning by pigeons and people, and recent neuroscientific research suggests that the basal ganglia, which are homologous in these species, may implement error-driven learning of stimulus-response associations. Furthermore, learning of abstract category representations can be observed in pigeons and other vertebrates. Finally, there is evidence that feedforward visual processing, a central mechanism in models of object recognition in the primate ventral stream, plays a role in object recognition by pigeons. We also highlight differences between pigeons and people in object recognition abilities, and propose candidate adaptive specializations which may explain them, such as holistic face processing and rule-based category learning in primates. From a modern comparative perspective, such specializations are to be expected regardless of the model species under study. The fact that we have a good idea of which aspects of object recognition differ in people and pigeons should be seen as an advantage over other animal models. From this perspective, we suggest that there is much to learn about human object recognition from studying the "simple" brains of pigeons.

  11. Response-cost punishment via token loss with pigeons.

    Science.gov (United States)

    Pietras, Cynthia J; Hackenberg, Timothy D

    2005-06-30

    Two experiments were conducted to investigate punishment via response-contingent removal of conditioned token reinforcers (response cost) with pigeons. In Experiment 1, key pecking was maintained on a two-component multiple second-order schedule of token delivery, with light emitting diodes (LEDs) serving as token reinforcers. In both components, responding produced tokens according to a random-interval 20-s schedule and exchange periods according to a variable-ratio schedule. During exchange periods, each token was exchangeable for 2.5-s access to grain. In one component, responses were conjointly punished according to fixed-ratio schedules of token removal. Response rates in this punishment component decreased to low levels while response rates in the alternate (no-punishment) component were unaffected. Responding was eliminated when it produced neither tokens nor exchange periods (Extinction), but was maintained at moderate levels when it produced tokens in the signaled absence of food reinforcement, suggesting that tokens served as effective conditioned reinforcers. In Experiment 2, the effect of the response-cost punishment contingency was separated from changes in the density of food reinforcement. This was accomplished by yoking either the number of food deliveries per component (Yoked Food) or the temporal placement of all stimulus events (tokens, exchanges, food deliveries) (Yoked Complete), from the punishment to the no-punishment component. Response rates decreased in both components, but decreased more rapidly and were generally maintained at lower levels in the punishment component than in the yoked component. In showing that the response-cost contingency had a suppressive effect on responding in addition to that produced by reductions in reinforcement density, the present results suggest that response-cost punishment shares important features with other forms of punishment.

  12. Taxonomy Icon Data: domestic pigeon [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available domestic pigeon Columba livia Chordata/Vertebrata/Aves Columba_livia_L.png Columba_livia_NL.png Columba..._livia_S.png Columba_livia_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Columba...+livia&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Columba+livia&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Col...umba+livia&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Columba+livia&t=NS ...

  13. 78 FR 38101 - Passenger Vessels Accessibility Guidelines

    Science.gov (United States)

    2013-06-25

    ... vessels. The proposed guidelines would afford these individuals equal opportunity to travel on passenger vessels for employment, transportation, public accommodation, and leisure. The proposed guidelines would... individuals equal opportunity to travel on passenger vessels for employment, transportation,...

  14. The influence of intertrial interval food on extinction and devaluation in chain schedules.

    Science.gov (United States)

    Bell, Matthew C; Goldenberg, Matthew; McDevitt, Margaret A

    2007-04-01

    The authors exposed pigeons to 2 equal 3-link chains by using variable-interval schedules of reinforcement. An intertrial interval (ITI) bisected by free food separated the chains. After baseline training, the authors presented terminal links in a successive discrimination to devalue 1 terminal link: The authors reinforced responses to 1 terminal link and extinguished responses to the other. The authors then presented full chains in extinction, except that they continued to deliver free food during the midpoint of the ITI. There were 2 principal findings. First, across all extinction conditions, responding decreased but did not extinguish. Second, when extinction testing revealed a terminal link devaluation effect in the 3rd condition, responding to the initial link was affected, but not middle-link responding. Overall, the results suggested that ITI food presentations can exert a substantial effect on responding in 3-link chain schedules, and they appear to influence both the pattern of extinction and devaluation effects.

  15. Gradual extinction reduces Reinstatement

    Directory of Open Access Journals (Sweden)

    Youssef eShiban

    2015-09-01

    Full Text Available The current study investigated whether gradually reducing the frequency of aversive stimuli during extinction can prevent the return of fear. Thirty-one participants of a three-stage procedure (acquisition, extinction and a reinstatement test on day two were randomly assigned to a standard extinction (SE and gradual extinction (GE procedure. The two groups differed only in the extinction procedure. While the SE group ran through a regular extinction process without any negative events, the frequency of the aversive stimuli during the extinction phase was gradually reduced for the GE group. The unconditioned stimulus was an air blast (5 bar, 10 ms. A spider and a scorpion were used as conditioned stimuli. The outcome variables were contingency ratings and physiological measures (skin conductance response and startle response. There were no differences found between the two groups for the acquisition and extinction phases concerning contingency ratings, SCR, or startle response. Gradual extinction compared to standard extinction significantly reduced the return of fear in the reinstatement test for the startle response but not for skin conductance response or contingency ratings. This study was successful in translating the findings in rodent to humans. The results suggest that the gradual extinction process is suitable for increasing the efficacy of fear extinction.

  16. Maintenance of transferrin polymorphism in pigeons

    Energy Technology Data Exchange (ETDEWEB)

    Frelinger, J.A.

    1972-02-01

    Transferrin, a nonheme iron-binding protein, is polymorphic in most vertebrate species that have been examined. In pigeons, it is controlled by an autosomal gene, with two known codominant alleles, Tf/sup A/ and Tf/sup B/. The two alleles are found in nearly equal frequencies and the three genotypes are at Hardy-Weinberg equilibrium in all populations studied. This report shows that ovotransferrins from heterozygous females inhibit microbial growth, by use of yeast as an assay organism, better than ovetransferrins from either of the homozygous types, or those from a mixture of homozygous types. Heterozygous females hatch a larger percentage of their eggs than homozygous females. This difference is probably accounted for by the transferrin effect. The failure of the mixture of the homozygous types to act like the heterozygous type calls into question the currently accepted structure of transferrin as a monomeric protein. The greater fecundity of heterozygous females can account for the maintenance of transferrin polymorphism in pigeons.

  17. The viruses of wild pigeon droppings.

    Directory of Open Access Journals (Sweden)

    Tung Gia Phan

    Full Text Available Birds are frequent sources of emerging human infectious diseases. Viral particles were enriched from the feces of 51 wild urban pigeons (Columba livia from Hong Kong and Hungary, their nucleic acids randomly amplified and then sequenced. We identified sequences from known and novel species from the viral families Circoviridae, Parvoviridae, Picornaviridae, Reoviridae, Adenovirus, Astroviridae, and Caliciviridae (listed in decreasing number of reads, as well as plant and insect viruses likely originating from consumed food. The near full genome of a new species of a proposed parvovirus genus provisionally called Aviparvovirus contained an unusually long middle ORF showing weak similarity to an ORF of unknown function from a fowl adenovirus. Picornaviruses found in both Asia and Europe that are distantly related to the turkey megrivirus and contained a highly divergent 2A1 region were named mesiviruses. All eleven segments of a novel rotavirus subgroup related to a chicken rotavirus in group G were sequenced and phylogenetically analyzed. This study provides an initial assessment of the enteric virome in the droppings of pigeons, a feral urban species with frequent human contact.

  18. Hierarchical group dynamics in pigeon flocks.

    Science.gov (United States)

    Nagy, Máté; Akos, Zsuzsa; Biro, Dora; Vicsek, Tamás

    2010-04-08

    Animals that travel together in groups display a variety of fascinating motion patterns thought to be the result of delicate local interactions among group members. Although the most informative way of investigating and interpreting collective movement phenomena would be afforded by the collection of high-resolution spatiotemporal data from moving individuals, such data are scarce and are virtually non-existent for long-distance group motion within a natural setting because of the associated technological difficulties. Here we present results of experiments in which track logs of homing pigeons flying in flocks of up to 10 individuals have been obtained by high-resolution lightweight GPS devices and analysed using a variety of correlation functions inspired by approaches common in statistical physics. We find a well-defined hierarchy among flock members from data concerning leading roles in pairwise interactions, defined on the basis of characteristic delay times between birds' directional choices. The average spatial position of a pigeon within the flock strongly correlates with its place in the hierarchy, and birds respond more quickly to conspecifics perceived primarily through the left eye-both results revealing differential roles for birds that assume different positions with respect to flock-mates. From an evolutionary perspective, our results suggest that hierarchical organization of group flight may be more efficient than an egalitarian one, at least for those flock sizes that permit regular pairwise interactions among group members, during which leader-follower relationships are consistently manifested.

  19. 49 CFR 523.4 - Passenger automobile.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Passenger automobile. 523.4 Section 523.4... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.4 Passenger automobile. A passenger automobile is any automobile (other than an automobile capable of off-highway operation)...

  20. Commercial Passenger Fishing Vessel Fishery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains the logbook data from U.S.A. Commercial Passenger Fishing Vessels (CPFV) fishing in the U.S.A. EEZ and in waters off of Baja California, from...

  1. Is extinction forever?

    Science.gov (United States)

    Smith-Patten, Brenda D; Bridge, Eli S; Crawford, Priscilla H C; Hough, Daniel J; Kelly, Jeffrey F; Patten, Michael A

    2015-05-01

    Mistrust of science has seeped into public perception of the most fundamental aspect of conservation-extinction. The term ought to be straightforward, and yet, there is a disconnect between scientific discussion and public views. This is not a mere semantic issue, rather one of communication. Within a population dynamics context, we say that a species went locally extinct, later to document its return. Conveying our findings matters, for when we use local extinction, an essentially nonsensical phrase, rather than extirpation, which is what is meant, then we contribute to, if not create outright, a problem for public understanding of conservation, particularly as local extinction is often shortened to extinction in media sources. The public that receives the message of our research void of context and modifiers comes away with the idea that extinction is not forever or, worse for conservation as a whole, that an extinction crisis has been invented.

  2. Mortality associated with fenbendazole administration in pigeons (Columba livia).

    Science.gov (United States)

    Gozalo, Alfonso S; Schwiebert, Rebecca S; Lawson, Gregory W

    2006-11-01

    A group of 12 domestic pigeons (Columba livia domestica) was treated for capillariasis by use of fenbendazole at 30 mg/kg orally once daily for 5 d. After treatment, 8 of the 12 pigeons exhibited signs of anorexia, lethargy, and dehydration; these birds died within 2 d after the onset of clinical signs. A total of 6 birds were necropsied, and all had unremarkable gross findings. Microscopic examination of tissues revealed acute hemorrhagic enteritis, diffuse lymphoplasmacytic enteritis, small intestinal crypt necrosis, periportal lymphoplasmacytic hepatitis, bile duct hyperplasia, and renal tubular necrosis. Erythrocytes in blood samples collected from surviving birds demonstrated polychromasia compatible with a regenerative anemia. The clinical and histopathologic findings in these pigeons were consistent with recent reports of fenbendazole toxicity in domestic pigeons and other columbiform birds.

  3. BackscatterA [8101]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  4. Isopachs--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the isopachs for the Pigeon Point to South Monterey Bay, California, region. The vector data file is included in...

  5. Transgressive Contours--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the transgressive contours for the Pigeon Point to South Monterey Bay, California, region. The vector file is included in...

  6. Sediment Thickness--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the sediment-thickness map of the Pigeon Point to South Monterey Bay, California, region. The raster data file is included in...

  7. BackscatterC [SWATH]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  8. BackscatterB [7125]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  9. Age and sex determination of juvenile band-tailed pigeons

    Science.gov (United States)

    White, J.A.; Braun, C.E.

    1978-01-01

    Captive band-tailed pigeons (Columbafasciata) were studied to document progression of molts and plumages from juvenal to adult age. Immature pigeons began the post-juvenal molt at 35 days which continued up to 340 days. The only 3 plumage characters useful for identification and estimation of age were presence of juvenal lesser, middle, and greater secondary coverts, juvenal secondaries, and juvenal primaries. While juvenal primaries were still present, hatching dates could be estimated up to 252 days (N = 84). Secondary feather presence and molt stage could be used to identify juvenile pigeons for more than 340 days (N = 24). Using coloration of the crown and breast feathers, 96 percent of the immature pigeons examined (106 of 110) at 80 days of age were classified accurately as to sex.

  10. Geology and geomorphology--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the geologic and geomorphic map of the Offshore Pigeon Point map area, California. The vector data file is included in...

  11. Isopachs--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the isopachs for the Pigeon Point to South Monterey Bay, California, region. The vector data file is included in...

  12. Transgressive Contours--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the transgressive contours for the Pigeon Point to South Monterey Bay, California, region. The vector file is included in...

  13. BackscatterA [8101]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  14. Sediment Thickness--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the sediment-thickness map of the Pigeon Point to South Monterey Bay, California, region. The raster data file is included in...

  15. BackscatterB [7125]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  16. Geology and geomorphology--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the geologic and geomorphic map of the Offshore Pigeon Point map area, California. The vector data file is included in...

  17. BackscatterC [SWATH]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  18. Telemedical Advice to Long Distance Passenger Ferries

    DEFF Research Database (Denmark)

    Jensen, Olaf Chresten; Bøggild, Niels Bo; Kristensen, Søren

    consultations with passenger ferries to identify areas for possible improvements. Methods: Data from the journals for one year from Radio Medical Denmark consultations with the medical Data from the journals for one year from Radio Medical Denmark consultations with the medical responsible officers on passenger...... ferries was analysed retrospectively. Results: Two hundred and fourteen RM records, 73% among passenger and 27% among crewmember Two hundred and fourteen RM records, 73% among passenger and 27% among crewmember patients were analysed. Passenger patients were generally older and more serious ill than...

  19. Pigeons can discriminate "good" and "bad" paintings by children.

    Science.gov (United States)

    Watanabe, Shigeru

    2010-01-01

    Humans have the unique ability to create art, but non-human animals may be able to discriminate "good" art from "bad" art. In this study, I investigated whether pigeons could be trained to discriminate between paintings that had been judged by humans as either "bad" or "good". To do this, adult human observers first classified several children's paintings as either "good" (beautiful) or "bad" (ugly). Using operant conditioning procedures, pigeons were then reinforced for pecking at "good" paintings. After the pigeons learned the discrimination task, they were presented with novel pictures of both "good" and "bad" children's paintings to test whether they had successfully learned to discriminate between these two stimulus categories. The results showed that pigeons could discriminate novel "good" and "bad" paintings. Then, to determine which cues the subjects used for the discrimination, I conducted tests of the stimuli when the paintings were of reduced size or grayscale. In addition, I tested their ability to discriminate when the painting stimuli were mosaic and partial occluded. The pigeons maintained discrimination performance when the paintings were reduced in size. However, discrimination performance decreased when stimuli were presented as grayscale images or when a mosaic effect was applied to the original stimuli in order to disrupt spatial frequency. Thus, the pigeons used both color and pattern cues for their discrimination. The partial occlusion did not disrupt the discriminative behavior suggesting that the pigeons did not attend to particular parts, namely upper, lower, left or right half, of the paintings. These results suggest that the pigeons are capable of learning the concept of a stimulus class that humans name "good" pictures. The second experiment showed that pigeons learned to discriminate watercolor paintings from pastel paintings. The subjects showed generalization to novel paintings. Then, as the first experiment, size reduction test

  20. The Other Shoe: An Early Operant Conditioning Chamber for Pigeons

    OpenAIRE

    Sakagami, Takayuki; Lattal, Kennon A.

    2016-01-01

    We describe an early operant conditioning chamber fabricated by Harvard University instrument maker Ralph Gerbrands and shipped to Japan in 1952 in response to a request of Professor B. F. Skinner by Japanese psychologists. It is a rare example, perhaps the earliest still physically existing, of such a chamber for use with pigeons. Although the overall structure and many of the components are similar to contemporary pigeon chambers, several differences are noted and contrasted to evolutionary...

  1. Pigeons' discrimination of paintings by Monet and Picasso

    OpenAIRE

    Watanabe, Shigeru; Sakamoto, Junko; Wakita, Masumi

    1995-01-01

    Pigeons successfully learned to discriminate color slides of paintings by Monet and Picasso. Following this training, they discriminated novel paintings by Monet and Picasso that had never been presented during the discrimination training. Furthermore, they showed generalization from Monet's to Cezanne's and Renoir's paintings or from Picasso's to Braque's and Matisse's paintings. These results suggest that pigeons' behavior can be controlled by complex visual stimuli in ways that suggest cat...

  2. Possible routes for lead accumulation in feral pigeons (Columba livia).

    Science.gov (United States)

    Nam, Dong-Ha; Lee, Doo-Pyo

    2006-10-01

    This study examined possible routes for lead (Pb) accumulation in resident pigeons collected from rural, urban, and four industrial sites in Korea. The accumulation pattern of Pb was comparable to the study sites. The highest Pb concentration was found in the bone, followed by kidney, liver, and lung of pigeons. Highest Pb residues in bones were found in urban (Seoul), and two industrial complex areas (Busan and Ulsan), which were about 15 times higher than rural area (Duckjuk island), and followed by Ansan and Yochon industrial areas. Regional Pb variations in liver, kidney, and lung tissues were also similar pattern with the bone Pb difference. These findings indicate that Pb accumulation in tissues of pigeons may be affected by the Pb exposure in their respective habitats. Crop contents and gizzard materials were investigated as representing the ingested items. No difference of Pb concentration was observed in major foods (maize and/or wheat) of crop contents in the study sites except Busan, whereas variations of Pb levels in gizzard materials were indicative of a similar pattern with tissue Pb differences. The Pb concentration in tissues of pigeons did not correspond well to the atmospheric Pb levels. With regard to possible Pb sources, ingested items especially materials present in the gizzard are important sources for Pb contamination to pigeons because Pb-containing sources may be expected to present in roadside particles, dusts, paint chips and building flakes. However, air Pb value being low may not affect significant as the regional variations in tissues of pigeons.

  3. Complex conditional control by pigeons in a continuous virtual environment.

    Science.gov (United States)

    Qadri, Muhammad A J; Reid, Sean; Cook, Robert G

    2016-01-01

    We tested two pigeons in a continuously streaming digital environment. Using animation software that constantly presented a dynamic, three-dimensional (3D) environment, the animals were tested with a conditional object identification task. The correct object at a given time depended on the virtual context currently streaming in front of the pigeon. Pigeons were required to accurately peck correct target objects in the environment for food reward, while suppressing any pecks to intermixed distractor objects which delayed the next object's presentation. Experiment 1 established that the pigeons' discrimination of two objects could be controlled by the surface material of the digital terrain. Experiment 2 established that the pigeons' discrimination of four objects could be conjunctively controlled by both the surface material and topography of the streaming environment. These experiments indicate that pigeons can simultaneously process and use at least two context cues from a streaming environment to control their identification behavior of passing objects. These results add to the promise of testing interactive digital environments with animals to advance our understanding of cognition and behavior.

  4. Sleep deprivation in pigeons and rats using motion detection.

    Science.gov (United States)

    Newman, Sarah M; Paletz, Elliott M; Obermeyer, William H; Benca, Ruth M

    2009-10-01

    Forced sleep deprivation results in substantial behavioral and physiologic effects in mammals. The disk-over-water (DOW) method produces a syndrome characterized by increased energy expenditure and a robust preferentially rapid-eye-movement sleep rebound upon recovery or eventual death after several weeks of sleep deprivation. The DOW has been used successfully only in rats. This paper presents a method to enforce long-term controlled sleep deprivation across species and to compare its effects in rats and pigeons. A conveyor was substituted for the DOW disk. Behavior rather than electroencephalography was used to trigger arousal stimuli, as in gentle-handling deprivation. Rats and pigeons were deprived using this apparatus, and the results were compared with each other and with published reports. The physiologic consequences and recovery sleep in rats were like those published for DOW rats. Magnitude of sleep loss and recovery patterns in pigeons were similar to those seen in rats, but expected symptoms of the sleep deprivation syndrome were absent in pigeons. The use of a motion trigger allowed us to measure and, thus, to assess the quality and impact of the procedure. Prolonged and controlled sleep deprivation can be enforced using automated motion detection and a conveyor-over-water system. Pigeons and rats, deprived of sleep to the same extent, showed similar patterns of recovery sleep, but pigeons did not exhibit the hyperphagia, weight loss, and debilitation seen in rats.

  5. Pigeon visual short-term memory directly compared to primates.

    Science.gov (United States)

    Wright, Anthony A; Elmore, L Caitlin

    2016-02-01

    Three pigeons were trained to remember arrays of 2-6 colored squares and detect which of two squares had changed color to test their visual short-term memory. Procedures (e.g., stimuli, displays, viewing times, delays) were similar to those used to test monkeys and humans. Following extensive training, pigeons performed slightly better than similarly trained monkeys, but both animal species were considerably less accurate than humans with the same array sizes (2, 4 and 6 items). Pigeons and monkeys showed calculated memory capacities of one item or less, whereas humans showed a memory capacity of 2.5 items. Despite the differences in calculated memory capacities, the pigeons' memory results, like those from monkeys and humans, were all well characterized by an inverse power-law function fit to d' values for the five display sizes. This characterization provides a simple, straightforward summary of the fundamental processing of visual short-term memory (how visual short-term memory declines with memory load) that emphasizes species similarities based upon similar functional relationships. By closely matching pigeon testing parameters to those of monkeys and humans, these similar functional relationships suggest similar underlying processes of visual short-term memory in pigeons, monkeys and humans. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Hierarchical group dynamics in pigeon flocks

    CERN Document Server

    Nagy, Mate; Biro, Dora; Vicsek, Tamas; 10.1038/nature08891

    2010-01-01

    Animals that travel together in groups display a variety of fascinating motion patterns thought to be the result of delicate local interactions among group members. Although the most informative way of investigating and interpreting collective movement phenomena would be afforded by the collection of high-resolution spatiotemporal data from moving individuals, such data are scarce and are virtually non-existent for long-distance group motion within a natural setting because of the associated technological difficulties. Here we present results of experiments in which track logs of homing pigeons flying in flocks of up to 10 individuals have been obtained by high-resolution lightweight GPS devices and analyzed using a variety of correlation functions inspired by approaches common in statistical physics. We find a well-defined hierarchy among flock members from data concerning leading roles in pairwise interactions, defined on the basis of characteristic delay times between birds' directional choices. The averag...

  7. Misinformed leaders lose influence over pigeon flocks.

    Science.gov (United States)

    Watts, Isobel; Nagy, Máté; Burt de Perera, Theresa; Biro, Dora

    2016-09-01

    In animal groups where certain individuals have disproportionate influence over collective decisions, the whole group's performance may suffer if these individuals possess inaccurate information. Whether in such situations leaders can be replaced in their roles by better-informed group mates represents an important question in understanding the adaptive consequences of collective decision-making. Here, we use a clock-shifting procedure to predictably manipulate the directional error in navigational information possessed by established leaders within hierarchically structured flocks of homing pigeons (Columba livia). We demonstrate that in the majority of cases when leaders hold inaccurate information they lose their influence over the flock. In these cases, inaccurate information is filtered out through the rearrangement of hierarchical positions, preventing errors by former leaders from propagating down the hierarchy. Our study demonstrates that flexible decision-making structures can be valuable in situations where 'bad' information is introduced by otherwise influential individuals.

  8. Modern examples of extinctions

    DEFF Research Database (Denmark)

    Lövei, Gabor L

    2013-01-01

    No species lives forever, and extinction is the ultimate fate of all living species. The fossil record indicates that a recent extinction wave affecting terrestrial vertebrates was parallel with the arrival of modern humans to areas formerly uninhabited by them. These modern instances of extinction...... started at around 40,000 years ago. On continents, large mammals (especially those >50 kg body mass) were affected, while on islands, the impacts were mainly felt by birds. The causes of these extinctions are not well known but hunting, habitat alteration and the introduction of non-native species...... reasons (certain groups do not fossilize) and methodological problems (methods of excavation and identification). Consequently, we can only crudely estimate the current rate of extinction. Nonetheless, it is evident that humans generated a new mass extinction, affecting all species in all habitats, and...

  9. Modern examples of extinctions

    DEFF Research Database (Denmark)

    Lövei, Gabor L

    2013-01-01

    No species lives forever, and extinction is the ultimate fate of all living species. The fossil record indicates that a recent extinction wave affecting terrestrial vertebrates was parallel with the arrival of modern humans to areas formerly uninhabited by them. These modern instances of extinction...... started at around 40,000 years ago. On continents, large mammals (especially those >50 kg body mass) were affected, while on islands, the impacts were mainly felt by birds. The causes of these extinctions are not well known but hunting, habitat alteration and the introduction of non-native species...... are the main causes of extinction. Our knowledge about extinctions is very incomplete, due to bias in research by taxonomy (vertebrate groups are better studied), geography (northern areas have received more attention), habitat (terrestrial habitats are better known than marine ones), as well as biological...

  10. The prevalence and genetic characterization of Chlamydia psittaci from domestic and feral pigeons in Poland and the correlation between infection rate and incidence of pigeon circovirus.

    Science.gov (United States)

    Stenzel, Tomasz; Pestka, Daria; Choszcz, Dariusz

    2014-12-01

    Chlamydiosis is a zoonotic disease caused by Chlamydia psittaci that occurs in a wide range of bird species. High infection rates with C. psittaci are found in pigeons, which can act as vectors transmitting this bacterium to poultry and humans. Chlamydia shedding by pigeons is intermittent and can be activated by stressors or immunosuppression. The most common immunosuppressive factor for pigeons is a pigeon circovirus (PiCV) infection. The main aim of the study was to evaluate the prevalence of C. psittaci in Polish populations of domestic and feral pigeons (Columba livia) in the context of its correlation with PiCV infections. The second objective was to determine the genetic characteristics of Polish C. psittaci isolates. The study was conducted on 377 pigeon samples (276 domestic and 101 feral pigeons) collected from pigeons from different regions of Poland. The average prevalence of C. psittaci in the Polish pigeon population was determined at 6.8%, and it was higher in domestic than in feral pigeons. This is the first ever study to suggest a potential correlation between C. psittaci and PiCV infections, which could be attributed to the fact that there are 2 to 3 times more pigeons infected with C. psittaci and coinfected with PiCV than pigeons infected with C. psittaci alone. This trend was observed mainly in the population of sick pigeons. As many as 88.2% of isolates were recognized as belonging to genotype B, and the remaining isolates were identified as belonging to genotype E. The isolates analyzed in this study demonstrated low levels of genetic variation (96-100% homology among the isolates and in relation to reference strains). Chlamydia psittaci could be expected to spread across pigeon populations due to the high probability of mutual infections between birds and the increasing number of PiCV infections.

  11. Development of Passenger Air Carriers

    Directory of Open Access Journals (Sweden)

    Igor Diminik

    2006-09-01

    Full Text Available The work presents the development of carriers in passengerair traffic, and the focus is on the development and operationsof carriers in chartered passenger transport. After the SecondWorld War, there were only scheduled air carriers. The need formass transport of tourists resulted in the development of chartercarriers or usage of scheduled carriers under different commercialconditions acceptable for tourism. Eventually also low-costcarriers appeared and they realize an increasing share in thepassenger transport especially in the aviation developed countries.

  12. Mass extinction: a commentary

    Science.gov (United States)

    Raup, D. M.

    1987-01-01

    Four neocatastrophist claims about mass extinction are currently being debated; they are that: 1, the late Cretaceous mass extinction was caused by large body impact; 2, as many as five other major extinctions were caused by impact; 3, the timing of extinction events since the Permian is uniformly periodic; and 4, the ages of impact craters on Earth are also periodic and in phase with the extinctions. Although strongly interconnected the four claims are independent in the sense that none depends on the others. Evidence for a link between impact and extinction is strong but still needs more confirmation through bed-by-bed and laboratory studies. An important area for future research is the question of whether extinction is a continuous process, with the rate increasing at times of mass extinctions, or whether it is episodic at all scales. If the latter is shown to be generally true, then species are at risk of extinction only rarely during their existence and catastrophism, in the sense of isolated events of extreme stress, is indicated. This is line of reasoning can only be considered an hypothesis for testing. In a larger context, paleontologists may benefit from a research strategy that looks to known Solar System and Galactic phenomena for predictions about environmental effects on earth. The recent success in the recognition of Milankovitch Cycles in the late Pleistocene record is an example of the potential of this research area.

  13. Transitive inference in pigeons: measuring the associative values of Stimuli B and D.

    Science.gov (United States)

    Lazareva, Olga F; Wasserman, Edward A

    2012-03-01

    Several reinforcement-based models have been proposed to explain transitive-like behavior in nonverbal transitive inference tasks. These models assume that the initial training required for memorizing the premises produces an ordered series of associative values (A>B>C>D>E); these values can then be used to select the "transitively correct" stimulus in a novel pair (e.g., BD). Our study experimentally tested this assumption by using resistance-to-extinction and resistance-to-reinforcement techniques to obtain empirical measures of associative strength for Stimuli B and D. We first measured the associative strengths of these stimuli after completion of initial training with overlapping pairs of colored squares (A+B-, B+C-, C+D-, and D+E-) using resistance-to-extinction and resistance-to-reinforcement procedures. Next, we used massed presentations of Pair D+E- (termed bias reversal) that ought to increase the associative value of Stimulus D, and again measured the associative strengths of the stimuli. None of our experimental measures of associative strength correlated with pigeons' behavior in the BD test or with BD performance predicted by associative models either before or after bias reversal (Wynne, 1995; Siemann and Delius, 1998). These results question validity of reinforcement-based models for explaining animals' behavior in nonverbal TI tasks.

  14. Parasites of domestic pigeons (Columba livia domestica in Sebele, Gaborone, Botswana : short communication

    Directory of Open Access Journals (Sweden)

    E.Z. Mushi

    2000-07-01

    Full Text Available The following parasites were found in apparently healthy pigeons kept in Sebele: a haemoprotozoan, Haemoproteus columbae (80 %; endoparasite metazoan nematodes, Ascaridia columbae(30 % and Dispharynx spiralis(10 %; a cestode, Raillietina sp. (80 % and coccidian oocysts (40 %; 2 ectoparasites, namely the pigeon fly, Pseudolynchia canariensis (50 % and the louse, Columbicola columbae (30 %. The pigeons also had high antibody titres, (1:256 to the protozoan parasite Toxoplasma gondii (100 %. The latter infection in these domestic pigeons has public health implications.

  15. Network structure of subway passenger flows

    CERN Document Server

    Xu, Qi; Bai, Yun

    2016-01-01

    The results of transportation infrastructure network analyses have been used to analyze complex networks in a topological context. However, most modeling approaches, including those based on complex network theory, do not fully account for real-life traffic patterns and may provide an incomplete view of network functions. This study utilizes trip data obtained from the Beijing Subway System to characterize individual passenger movement patterns. A directed weighted passenger flow network was constructed from the subway infrastructure network topology by incorporating trip data. The passenger flow networks exhibit several properties that can be characterized by power-law distributions based on flow size, and log-logistic distributions based on the fraction of boarding and departing passengers. The study also characterizes the temporal patterns of in-transit and waiting passengers and provides a hierarchical clustering structure for passenger flows. This hierarchical flow organization varies in the spatial doma...

  16. Complete genome sequence of genotype VI Newcastle disease viruses isolated from pigeons in Pakistan

    Science.gov (United States)

    Two complete genome sequences of Newcastle disease virus (NDV) are described here. Virulent isolates pigeon/Pakistan/Lahore/21A/2015 and pigeon/Pakistan/Lahore/25A/2015 were obtained from racing pigeons sampled in the Pakistani province of Punjab during 2015. Phylogenetic analysis of the fusion prot...

  17. Helicopter crew/passenger vibration sensitivity -

    Science.gov (United States)

    Gabel, R.; Reed, D. A.

    1972-01-01

    Helicopter crew and passenger vibration sensitivity are presented. Pilot subjective ratings are established for discrete frequencies and the impact of combinations of harmonic frequencies is examined. A passenger long term comfort level and a short term limit are defined for discrete frequencies and compared with pilot ratings. The results show reasonable agreement between pilot and passenger. Subjective comfort levels obtained for mixed frequency environments clearly demonstrate the need for a multi-frequency criterion.

  18. A shared " passengers & goods " city logistics system

    OpenAIRE

    2012-01-01

    International audience; Many strategic planning models have been developed to help decision making in city logistics. Such models do not take into account, or very few, the flow of passengers because the considered unit does not have the same nature (a person is active and a good is passive). However, it seems fundamental to gather the goods and the passengers in one model when their respective transports interact with each other. In this context, we suggest assessing a shared passengers & go...

  19. Pigeons are Not Susceptible to Intracloacal Infection with Histomonas meleagridis

    Directory of Open Access Journals (Sweden)

    Rüdiger Hauck and Hafez M. Hafez*

    2012-10-01

    Full Text Available Histomonas meleagridis is a trichomonad parasite, which is capable to cause severe inflammations of ceca and livers in gallinaceous birds. It rarely can be satisfactorily explained, how the parasite was introduced into the flock. The role of wild birds as possible reservoir or as vectors has not been explored sufficiently. In the present study two experiments were done to determine if pigeons are susceptible to intracloacal infections with H. meleagridis and have the potential to act as vectors. In a first experiment nine racing pigeons (Columba livia forma domestica were infected intracloacally with 400,000 living histomonads. Three further pigeons were kept as contact birds. Histomonal DNA was detected in cloacal swabs until one week after infection, but reisolation was not possible. In a second experiment 24 racing pigeons were either infected intracloacally with 250,000 viable histomonads or with the same culture, which had been inactivated. Histomonal DNA was detected in cloacal swabs of both groups until five days after infection, but reisolation was not possible. In both experiments neither clinical signs nor gross lesions were observed in any bird and in the ceca no histomonal DNA was detected. It was concluded that pigeons do not act as vectors for H. meleagridis after intracloacal infection.

  20. Perception of complex motion in humans and pigeons (Columba livia).

    Science.gov (United States)

    Nankoo, Jean-François; Madan, Christopher R; Spetch, Marcia L; Wylie, Douglas R

    2014-06-01

    In the primate visual system, local motion signals are pooled to create a global motion percept. Like primates, many birds are highly dependent on vision for their survival, yet relatively little is known about motion perception in birds. We used random-dot stimuli to investigate pigeons' ability to detect complex motion (radial, rotation, and spiral) compared to humans. Our human participants had a significantly lower threshold for rotational and radial motion when compared to spiral motion. The data from the pigeons, however, showed that the pigeons were most sensitive to rotational motion and least sensitive to radial motion, while sensitivity for spiral motion was intermediate. We followed up the pigeon results with an investigation of the effect of display aperture shape for rotational motion and velocity gradient for radial motion. We found no effect of shape of the aperture on thresholds, but did observe that radial motion containing accelerating dots improved thresholds. However, this improvement did not reach the thresholds levels observed for rotational motion. In sum, our experiments demonstrate that the pooling mechanism in the pigeon motion system is most efficient for rotation.

  1. Switching hierarchical leadership mechanism in homing flight of pigeon flocks

    Science.gov (United States)

    Chen, Duxin; Vicsek, Tamás; Liu, Xiaolu; Zhou, Tao; Zhang, Hai-Tao

    2016-06-01

    To explore the fascinating inter-individual interaction mechanism governing the abundant biological grouping behaviors, more and more efforts have been devoted to collective motion investigation in recent years. Therein, bird flocking is one of the most intensively studied behaviors. A previous study (Nagy M. et al., Nature, 464 (2010) 890.) claims the existence of a well-defined hierarchical structure in pigeon flocks, which implies that a multi-layer leadership network leads to the occurrence of highly coordinated pigeon flock movements. However, in this study, by using high-resolution GPS data of homing flight of pigeon flocks, we reveal an explicit switching hierarchical mechanism underlying the group motions of pigeons. That is, a pigeon flock has a long-term leader for smooth moving trajectories, whereas the leading tenure passes to a temporary one upon sudden turns or zigzags. Therefore, the present observation helps explore more deeply into the principle of a huge volume of bird flocking dynamics. Meanwhile, from the engineering point of view, it may shed some light onto industrial multi-robot coordination and unmanned air vehicle formation control.

  2. Lomba Merpati: Place-making and Communal Signalling within Javanese Pigeon Racing.

    Directory of Open Access Journals (Sweden)

    Leyla Stevens

    2016-02-01

    Full Text Available The project, Lomba Merpati, is a series of photographs and video works documenting pigeon racing in Yogyakarta, Indonesia. Associated as a lower socio-economic class sport and tied up with expressions of Javanese masculinity, pigeon racing occupies a central position within much of the daily social activity of Javanese villages.  The project explores the significance of pigeon training grounds as communal gathering points for young men in Yogyakarta. Comprising short video and photographic portraits, the series focuses on the performative gestures enacted by pigeon fanciers as they train their pigeons for short distance sprinting.

  3. Categorization of birds, mammals, and chimeras by pigeons.

    Science.gov (United States)

    Cook, Robert G; Wright, Anthony A; Drachman, Eric E

    2013-02-01

    Identifying critical features that control categorization of complex polymorphous pictures by animals remains a challenging and important problem. Toward this goal, experiments were conducted to isolate the properties controlling the categorization of two pictorial categories by pigeons. Pigeons were trained in a go/no-go task to categorize black and white line drawings of birds and mammals. They were then tested with a variety of familiar and novel exemplars of these categories to examine the features controlling this categorization. These tests suggested the pigeons were segregating and using the principal axis of orientation of the animal figures as the primary means of discriminating each category, although other categorical and item-specific cues were likely involved. This perceptual/cognitive reduction of the categorical stimulus space to a few visual features or dimensions is likely a characteristic of this species' processing of complex pictorial discrimination problems and is a critical property for theoretical accounts of this behavior.

  4. Dissociation of Procedural and Working Memory in Pigeons (Columba livia

    Directory of Open Access Journals (Sweden)

    Walter T. Herbranson

    2016-07-01

    Full Text Available A new method was developed to concurrently investigate procedural memory and working memory in pigeons. Pigeons performed a sequence of keypecks across 3 response keys in a serial response task, with periodic choice probes for the location of a recently produced response. Procedural memory was operationally defined as decreasing response times to predictable cues in the sequence. Working memory was reflected by accurate responses to the choice probes. Changing the sequence of required keypecks to a random sequence interfered with procedural memory in the form of slowed response times, but did not prevent pigeons from effectively using working memory to remember specific cue locations. Conversely, changing exposure duration of to a cue location influenced working memory but had no effect on procedural memory. Double dissociations such as this have supported the multiple systems approach to the study of memory in cognitive psychology and neuroscience, and they encourage a similar approach in comparative psychology.

  5. Multiple cue use and integration in pigeons (Columba livia).

    Science.gov (United States)

    Legge, Eric L G; Madan, Christopher R; Spetch, Marcia L; Ludvig, Elliot A

    2016-05-01

    Encoding multiple cues can improve the accuracy and reliability of navigation and goal localization. Problems may arise, however, if one cue is displaced and provides information which conflicts with other cues. Here we investigated how pigeons cope with cue conflict by training them to locate a goal relative to two landmarks and then varying the amount of conflict between the landmarks. When the amount of conflict was small, pigeons tended to integrate both cues in their search patterns. When the amount of conflict was large, however, pigeons used information from both cues independently. This context-dependent strategy for resolving spatial cue conflict agrees with Bayes optimal calculations for using information from multiple sources.

  6. Endoscopic Vasectomy of Male Feral Pigeons (Columba livia) as a Possible Method of Population Control.

    Science.gov (United States)

    Heiderich, Elisabeth; Schildger, Bernd; Lierz, Michael

    2015-03-01

    To evaluate whether single-entry endoscopic vasectomy of male feral pigeons (Columba livia) significantly reduced fertility and would potentially be valuable for control of feral pigeon populations, 252 male feral pigeons were caught in the city of Berne and endoscopically vasectomized. In this procedure, approximately 1 cm of the deferent duct was removed bilaterally. Rapid, uneventful recoveries occurred in 94% (237/252) of the pigeons, whereas 6% (15/252) died because of complications associated with the procedure, consisting of perforation of the ureter (9/15), major hemorrhage (5/15), and respiratory arrest (1/15). Mean anesthesia time was 23±6 minutes. The vasectomized males were habituated to 2 pigeon houses together with fertile females. Another pigeon house with fertile pairs acted as control. All eggs laid were candled weekly to assess fertility. In the 2 pigeon houses with vasectomized males, the mean fertilization rate was 0.9% (5/563), while in the control pigeon house, the rate was 100% (39/39). The results indicate that endoscopic vasectomy of male feral pigeons may be a promising tool for field control of feral pigeon populations, especially in combination with other methods such as pigeon houses.

  7. Identification and Immune Functional Characterization of Pigeon TLR7

    Directory of Open Access Journals (Sweden)

    Dan Xiong

    2015-04-01

    Full Text Available Toll-like receptor 7 (TLR7 is activated by single-stranded RNA and synthetic imidazoquinoline components, and induces interferon production. In this study, we cloned the TLR7 gene from King pigeon (Columba livia. The TLR7 open reading frame is 3144 bp and encodes a 1047-amino acid protein, consisting of a canonical TLR composition with 15 leucine-rich repeats (LRRs. Amino acid-inserting modifications were found at position 15 of LRR2, LRR11, LRR13, and LRR14 and position 10 of LRR10. The tissue distribution of pigeon TLR7 suggests that immune-associated tissues, especially the spleen and liver, have high TLR7 expression. HEK293T cells transfected with pigeon TLR7 plasmid responded to the agonist R848, indicating a functional TLR7 homolog. Following R848 stimulation of pigeon peripheral blood mononuclear cells, the levels of IFN-γ, IL-6, IL-8, CCL5, and IL-10 mRNA, assessed using quantitative real-time PCR, were significantly up-regulated. After Newcastle disease virus vaccine strain LaSota inoculation and agonist R848 injection, the level of TLR7 mRNA in the spleen of pigeons increased significantly in the R848-injected group, but decreased in the LaSota-inoculated group at three day post-infection (d.p.i.. The mRNA levels of inflammatory cytokines and chemokines were significantly upregulated in both LaSota-inoculated and R848-injected groups. Triggering pigeon TLR7 leads to robust up-regulation of inflammatory cytokines and chemokines, suggesting an important role in the innate immune response.

  8. The Driving Factors of Passenger Transport

    NARCIS (Netherlands)

    De Jong, G.C.; Van de Riet, O.A.W.T.

    2008-01-01

    Over the past few decades passenger transport has grown rapidly resulting in a multitude of problems including severe traffic congestion and pollution. It is expected that passenger transport will continue to grow rapidly in the future, which will worsen the situation even further. The traditional

  9. Passenger transport and household activity patterns

    DEFF Research Database (Denmark)

    Jørgensen, Kaj

    1997-01-01

    Review of Danish passenger transport patterns and analysis of energy consumption, emissions and safety impacts for selected typical households' travelling......Review of Danish passenger transport patterns and analysis of energy consumption, emissions and safety impacts for selected typical households' travelling...

  10. Young drivers and their young passengers.

    NARCIS (Netherlands)

    2015-01-01

    More than one-third of all fatalities among car passengers occurs in the 10-24-year age group. The majority of these young passengers die in a car driven by an 18 to 24-year old. Compared with the composition of the population, these are high proportions, yet the exposure (for example in distance tr

  11. Young drivers and their young passengers.

    NARCIS (Netherlands)

    2015-01-01

    More than one-third of all fatalities among car passengers occurs in the 10-24-year age group. The majority of these young passengers die in a car driven by an 18 to 24-year old. Compared with the composition of the population, these are high proportions, yet the exposure (for example in distance

  12. Young drivers and their young passengers.

    NARCIS (Netherlands)

    2015-01-01

    More than one-third of all fatalities among car passengers occurs in the 10-24-year age group. The majority of these young passengers die in a car driven by an 18 to 24-year old. Compared with the composition of the population, these are high proportions, yet the exposure (for example in distance tr

  13. Should Passengers Be Responsible For Drunk Drivers?

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In late September, China’s Ministry of Public Security expanded its nationwide campaign against drunk driving by releasing a document suggesting that passengers sharing a car with a drunk driver be punished together with the driver and that passengers who do not prevent drunk driving be fined.

  14. Crew Management in Passenger Rail Transport

    NARCIS (Netherlands)

    E.J.W. Abbink (Erwin)

    2014-01-01

    textabstract__Abstract__ Crew management in passenger rail transport is an important factor that contributes to both the quality of service to the railway passengers and to the operational costs of the train operating company. This thesis describes how the (railway) Crew Management process can be i

  15. Prediction of Railway Passenger Traffic Volume

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The current situation of the railway passenger traffic (RPT) andthe traffic marketing is analyzed. The grey model theory is adopted to establish a prediction model for the railway passenger traffic volume (RPTV). The RPTV from 2001 to 2005 is predicted with the proposed model, and a few suggestions are put forward.

  16. 77 FR 38248 - Passenger Train Emergency Preparedness

    Science.gov (United States)

    2012-06-27

    ... Federal Railroad Administration 49 CFR Part 239 Passenger Train Emergency Preparedness AGENCY: Federal... (NPRM). SUMMARY: FRA is proposing to revise its regulations for passenger train emergency preparedness... responders during emergency situations receive initial and periodic training and are subject to operational...

  17. Train Timetable Evaluation from the Viewpoints of Passengers by Microsimulation of Train Operation and Passenger Flow

    Science.gov (United States)

    Kunimatsu, Taketoshi; Hirai, Chikara; Tomii, Norio

    In order to evaluate train timetables from passengers' points of view, it is indispensable to estimate the disutilities of passengers. This can be done by estimating the movements of passengers and trains accurately. In particular, when there are many passengers, an interaction between the passengers and trains must be considered. To this end, we have developed a microsimulation system to simulate both train operation and passengers' train choice behavior. The system can simulate train choice behaviors of more than one million passengers as well as their positions in trains. It is possible to estimate the delays caused by congestion in trains as well. The system is based on models of different attitudes of the passengers with respect to the train choice behavior, with includes the choice of the earliest train, transfer avoidance, and congestion avoidance; a passengers' train choice behavior reflects his/her preferences. We applied this system to an actual railway line in a metropolitan area and evaluated two train schedules by calculating the generalized cost that reflects each passenger's disutility in his/her experience. Through the numerical experiments, we have confirmed that the proposed method is very useful for evaluating timetables from passengers' points of view.

  18. Temporal Dynamics of Recovery from Extinction Shortly after Extinction Acquisition

    Science.gov (United States)

    Archbold, Georgina E.; Dobbek, Nick; Nader, Karim

    2013-01-01

    Evidence suggests that extinction is new learning. Memory acquisition involves both short-term memory (STM) and long-term memory (LTM) components; however, few studies have examined early phases of extinction retention. Retention of auditory fear extinction was examined at various time points. Shortly (1-4 h) after extinction acquisition…

  19. The Other Shoe: An Early Operant Conditioning Chamber for Pigeons.

    Science.gov (United States)

    Sakagami, Takayuki; Lattal, Kennon A

    2016-05-01

    We describe an early operant conditioning chamber fabricated by Harvard University instrument maker Ralph Gerbrands and shipped to Japan in 1952 in response to a request of Professor B. F. Skinner by Japanese psychologists. It is a rare example, perhaps the earliest still physically existing, of such a chamber for use with pigeons. Although the overall structure and many of the components are similar to contemporary pigeon chambers, several differences are noted and contrasted to evolutionary changes in this most important laboratory tool in the experimental analysis of behavior. The chamber also is testimony to the early internationalization of behavior analysis.

  20. ISOLATION AND DETECTION OF CRYPTOCOCCUS NEOFORMANS FROM PIGEON DROPPINGS: ISFAHAN AND IT"S SUBURBS PROVINCE PIGEON TOWERS

    Directory of Open Access Journals (Sweden)

    B NASR ISFAHANI

    2001-06-01

    Full Text Available Introduction: Cryptococcus neoformans is an encapsulated yeast like and a principle cause of morbidity and mortality in immunocompromised hosts, especially those with AIDS. At the persent, due to progressive increase in predisposing factors to cryptococcosis and proper therapy, identification of this fungus has become more important than before. The most important sources of infection are contaminated pigeon droppings and soil. Since there are many so called .Pigeon Tower" in Isfahan and it"s suburbs, we decided to isolate and identify C.neoformans from pigeon droppings collected in these towers. It is notable that these pigeon droppings are traditionally used as natural fertilizer. Methods: After preparing suspensions of droppings, we spread them onto the surface of Niger seed agar and L-DOPA containing media. The identification of isolates was established by ureas test, India ink preparation, subculturing on CMA + Tween 80 medium, growth 37°c and assimilation of carbohydrates and nitrate. GCP (Glycine- Cyclohexaamide - Phenol red medium was used for distinguishing C.neoformans Var. neoformans from C. neoformans Var. gattii. The pathogenicity of the isolates was determined in mice by intracerebral inoculation. Results: c. neoformans was isolated from 11 of 136 samples (8.1 percent. All of them were identified as c. neoformans Var. neoformans. However, five of them (45.5 percent caused disease in mice. There was no statistically significant relation between the pH of the pigeon dropping and the precence of C.neoformans. Discussion: According to the results, it seems that the actual prevalance of cryptococcosis should be more than the reported cases. Regarding the relative frequency of the yeast in "Pigeon Towers" in Esfahan, as it was shown in this study, clinicians should pay more attention to this organism and its disease, especially in patients with predisposing factors.

  1. Cloning and expression of a truncated pigeon circovirus capsid protein suitable for antibody detection in infected pigeons.

    Science.gov (United States)

    Daum, Iris; Finsterbusch, Tim; Härtle, Stefan; Göbel, Thomas W; Mankertz, Annette; Korbel, Rüdiger; Grund, Christian

    2009-04-01

    Infections with pigeon circovirus (PiCV) (also termed columbid circovirus) occur in meat and racing pigeons (Columba livia) of all ages and have been reported worldwide. A PiCV infection is associated with immunosuppression and the development of young pigeon disease syndrome. An indirect enzyme-linked immunosorbent assay (ELISA) for the detection of virus-specific serum antibody was developed for research purposes. In the absence of a method to propagate PiCV in cell culture, the assay was based on a recombinant truncated capsid protein (rCapPiCV) produced by overexpression in Escherichia coli. A 6xHis-Tag was fused to the N-terminus of the protein to facilitate purification by metal affinity chromatography and detection by anti-His antibody. PiCV-negative and PiCV-positive control sera were generated by inoculation of pigeons with tissue homogenate containing PiCV, followed by five weekly blood sample collections. Western blotting of the immune serum revealed a specific protein band of approximately 32 kDa, which was absent in the pre-immune sera. Using rCapPiCV as antigen in an indirect ELISA, PiCV-specific antibody was detected in sera of the experimentally PiCV-infected pigeons collected at 1 to 5 weeks post infection. By testing 118 field sera collected in the years 1989, 1991, 1994 and 2008 in the rCapPiCV ELISA, virus-specific antibody was detected in 89 (75%) of the sera. The results obtained demonstrate that the rCapPiCV-based indirect ELISA is able to detect PiCV-specific antibodies in pigeon sera and may be a useful tool for PiCV serodiagnosis.

  2. the role of the pigeon in the first world war

    African Journals Online (AJOL)

    plt

    dedicated naval war pigeon service supported by the national fiscus,25 a formal .... society”, as well as in the formation and resilience of identity.61. Towards .... the besieged residents.”91 .... 7 Winter, C. “Tourism, social memory and the Great War”. ... a short time: New perspectives on the Anglo-Boer War, Pretoria: Nexus.

  3. PRODUCTIVITY, REPEATABILITY OF PRODUCTIVE AND REPRODUCTIVE TRAITS OF LOCAL PIGEON

    Directory of Open Access Journals (Sweden)

    S. Darwati

    2014-10-01

    Full Text Available The purpose of this study was to know productivity and repeatability of local pigeon. Data werecollected from 124 birds that reared under intensive management. The results showed that artificial pairwas 100% and polygamy was 16% (n=62 pair of pigeon. The ration of local pigeon consisting of 50%corn+50% of commercial feed for starter broiler chicken can be applied in field. The average of eggproduction was 1.8 eggs/pair/period, egg weight was 17.7 g, fertility was 96.6%, hatching rate was 77%,embryo mortality rate was 23%, interval period from laying to hatching and suckling was 51 days, 31.4days with hatching, and 17.6 days without hatching and suckling. The day old pigeon weight ranged10.9-16.2 g. Repeatability value of productive traits was high, in which egg weight was 0.64 and day oldpigeon weight was 0.737. Repeatability of reproductive traits was low, that was fertility and hatchabilitywas 0.12 and 0.048, respectively. The squab weight increased from week 0 to 4, then decreased in theweek 5. The growth rate was highest at the week 1, then decreased from the week 2 to 5 with thenegative growth rate occur at the 5th week. The squab growth rate followed a quadratic pattern. It wasconcluded that slaughter squab selection could be done at 4th week old.

  4. Associative Symmetry by Pigeons after Few-Exemplar Training

    Science.gov (United States)

    Velasco, Saulo M.; Huziwara, Edson M.; Machado, Armando; Tomanari, Gerson Y.

    2010-01-01

    The present experiment investigated whether pigeons can show associative symmetry on a two-alternative matching-to-sample procedure. The procedure consisted of a within-subject sequence of training and testing with reinforcement, and it provided (a) exemplars of symmetrical responding, and (b) all prerequisite discriminations among test samples…

  5. An Analysis of an Autoclitic Analogue in Pigeons

    Science.gov (United States)

    Kuroda, Toshikazu; Lattal, Kennon A.; García-Penagos, Andrés

    2014-01-01

    Using a conditional discrimination procedure, pigeons were exposed to a nonverbal analogue of qualifying autoclitics such as "definitely" and "maybe." It has been suggested that these autoclitics are similar to tacts except that they are under the control of private discriminative stimuli. Instead of the conventional assumption…

  6. Metabolic products in pigeon tissues after feeding glucose

    NARCIS (Netherlands)

    Reinking, A.; Steyn-Parvé, Elizabeth P.

    1964-01-01

    [14C6]Glucose was given orally to pigeons. After 3 h, the state—other than glycogen or fatty acids—in which radioactive carbon was present in the tissues was investigated. Nearly all the radioactive material could be extracted with 5% trichloroacetic acid. Most of the label thus extracted was

  7. Three-dimensional reconstruction of the pigeon inner ear

    NARCIS (Netherlands)

    Hofman, R.; Segenhout, J. M.; Wit, H. P.

    2009-01-01

    Three-dimensional reconstructions of the inner ear of the pigeon (Columba livia domestica), from two-dimensional images, obtained with (conventional) light microscopy or orthogonal-plane fluorescence optical sectioning (OPFOS), are presented. The results are compared with available information on th

  8. Matching-to-sample abstract-concept learning by pigeons.

    Science.gov (United States)

    Bodily, Kent D; Katz, Jeffrey S; Wright, Anthony A

    2008-01-01

    Abstract concepts--rules that transcend training stimuli--have been argued to be unique to some species. Pigeons, a focus of much concept-learning research, were tested for learning a matching-to-sample abstract concept. Five pigeons were trained with three cartoon stimuli. Pigeons pecked a sample 10 times and then chose which of two simultaneously presented comparison stimuli matched the sample. After acquisition, abstract-concept learning was tested by presenting novel cartoons on 12 out of 96 trials for 4 consecutive sessions. A cycle of doubling the training set followed by retraining and novel-testing was repeated eight times, increasing the set size from 3 to 768 items. Transfer performance improved from chance (i.e., no abstract-concept learning) to a level equivalent to baseline performance (>80%) and was similar to an equivalent function for same/different abstract-concept learning. Analyses assessed the possibility that item-specific choice strategies accounted for acquisition and transfer performance. These analyses converged to rule out item-specific strategies at all but the smallest set-sizes (3-24 items). Ruling out these possibilities adds to the evidence that pigeons learned the relational abstract concept of matching-to-sample.

  9. Altered orientation and flight paths of pigeons reared on gravity anomalies: a GPS tracking study.

    Science.gov (United States)

    Blaser, Nicole; Guskov, Sergei I; Meskenaite, Virginia; Kanevskyi, Valerii A; Lipp, Hans-Peter

    2013-01-01

    The mechanisms of pigeon homing are still not understood, in particular how they determine their position at unfamiliar locations. The "gravity vector" theory holds that pigeons memorize the gravity vector at their home loft and deduct home direction and distance from the angular difference between memorized and actual gravity vector. However, the gravity vector is tilted by different densities in the earth crust leading to gravity anomalies. We predicted that pigeons reared on different gravity anomalies would show different initial orientation and also show changes in their flight path when crossing a gravity anomaly. We reared one group of pigeons in a strong gravity anomaly with a north-to-south gravity gradient, and the other group of pigeons in a normal area but on a spot with a strong local anomaly with a west-to-east gravity gradient. After training over shorter distances, pigeons were released from a gravitationally and geomagnetically normal site 50 km north in the same direction for both home lofts. As expected by the theory, the two groups of pigeons showed divergent initial orientation. In addition, some of the GPS-tracked pigeons also showed changes in their flight paths when crossing gravity anomalies. We conclude that even small local gravity anomalies at the birth place of pigeons may have the potential to bias the map sense of pigeons, while reactivity to gravity gradients during flight was variable and appeared to depend on individual navigational strategies and frequency of position updates.

  10. Altered orientation and flight paths of pigeons reared on gravity anomalies: a GPS tracking study.

    Directory of Open Access Journals (Sweden)

    Nicole Blaser

    Full Text Available The mechanisms of pigeon homing are still not understood, in particular how they determine their position at unfamiliar locations. The "gravity vector" theory holds that pigeons memorize the gravity vector at their home loft and deduct home direction and distance from the angular difference between memorized and actual gravity vector. However, the gravity vector is tilted by different densities in the earth crust leading to gravity anomalies. We predicted that pigeons reared on different gravity anomalies would show different initial orientation and also show changes in their flight path when crossing a gravity anomaly. We reared one group of pigeons in a strong gravity anomaly with a north-to-south gravity gradient, and the other group of pigeons in a normal area but on a spot with a strong local anomaly with a west-to-east gravity gradient. After training over shorter distances, pigeons were released from a gravitationally and geomagnetically normal site 50 km north in the same direction for both home lofts. As expected by the theory, the two groups of pigeons showed divergent initial orientation. In addition, some of the GPS-tracked pigeons also showed changes in their flight paths when crossing gravity anomalies. We conclude that even small local gravity anomalies at the birth place of pigeons may have the potential to bias the map sense of pigeons, while reactivity to gravity gradients during flight was variable and appeared to depend on individual navigational strategies and frequency of position updates.

  11. Occupant safety in modern passenger cars.

    Science.gov (United States)

    Fildes, B N; Vulcan, A P; Lenard, J

    1992-06-01

    A study was undertaken recently for the Federal Office of Road Safety in Australia of 150 modern vehicle crashes where at least one of the vehicle occupants was admitted to hospital. The types of injuries sustained by occupants of modern Australian passenger cars involved in road crashes (including points of contact within the vehicle) were assessed to provide direction for future improvements in occupant protection. Seat belt performance in all seating positions was of particular interest. While the limited number of cases did not permit a full and detailed statistical analysis of these data, the findings nevertheless show there is scope for improving occupant protection for drivers and passengers of modern passenger cars.

  12. Comparison of airline passenger oxygen systems.

    Science.gov (United States)

    Byrne, N J

    1995-08-01

    The principal sources of oxygen for inflight passenger use, scheduled and unscheduled, are examined. Present practices of assessment of the passenger's "fitness to fly" are described. Three partner airlines, British Airways, U.S. Air, and Qantas, catering for more than 8000 oxygen requests annually, are compared. Analysis of customer use suggests that medical oxygen requests are frequently not clinically justified. The growth in demand, for both scheduled and unscheduled use of an expensive resource, supports the need for a "recommended best practice" among carriers. Passengers with respiratory disorders who will most benefit from inflight oxygen are vulnerable either to hypoxia or asthma.

  13. Hybridization and extinction.

    Science.gov (United States)

    Todesco, Marco; Pascual, Mariana A; Owens, Gregory L; Ostevik, Katherine L; Moyers, Brook T; Hübner, Sariel; Heredia, Sylvia M; Hahn, Min A; Caseys, Celine; Bock, Dan G; Rieseberg, Loren H

    2016-08-01

    Hybridization may drive rare taxa to extinction through genetic swamping, where the rare form is replaced by hybrids, or by demographic swamping, where population growth rates are reduced due to the wasteful production of maladaptive hybrids. Conversely, hybridization may rescue the viability of small, inbred populations. Understanding the factors that contribute to destructive versus constructive outcomes of hybridization is key to managing conservation concerns. Here, we survey the literature for studies of hybridization and extinction to identify the ecological, evolutionary, and genetic factors that critically affect extinction risk through hybridization. We find that while extinction risk is highly situation dependent, genetic swamping is much more frequent than demographic swamping. In addition, human involvement is associated with increased risk and high reproductive isolation with reduced risk. Although climate change is predicted to increase the risk of hybridization-induced extinction, we find little empirical support for this prediction. Similarly, theoretical and experimental studies imply that genetic rescue through hybridization may be equally or more probable than demographic swamping, but our literature survey failed to support this claim. We conclude that halting the introduction of hybridization-prone exotics and restoring mature and diverse habitats that are resistant to hybrid establishment should be management priorities.

  14. 49 CFR 523.5 - Non-passenger automobile.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Non-passenger automobile. 523.5 Section 523.5... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION VEHICLE CLASSIFICATION § 523.5 Non-passenger automobile. A non-passenger automobile means an automobile that is not a passenger automobile or a work truck and...

  15. A comparative infection study of pigeon and avian paramyxovirus type 1 viruses in pigeons: Evaluation of clinical signs, virus shedding and seroconversion

    NARCIS (Netherlands)

    Dortmans, J.C.F.M.; Koch, G.; Rottier, P.J.M.; Peeters, B.P.H.

    2011-01-01

    The pathogenesis of pigeon paramyxovirus type 1 (PPMV-1) isolate AV324/96 and of its recombinant derivative, rgAV324, was studied in pigeons. For comparison, the virulent chicken virus FL-Herts, which is a recombinant derivative of strain Herts/33, was also included. After inoculation by the combine

  16. Modeling and Optimization of Collaborative Passenger Control in Urban Rail Stations under Mass Passenger Flow

    Directory of Open Access Journals (Sweden)

    Lili Wang

    2015-01-01

    Full Text Available With the rapid development of urban rail transit, the phenomenon of outburst passenger flows flocking to stations is occurring much more frequently. Passenger flow control is one of the main methods used to ensure passengers’ safety. While most previous studies have only focused on control measures inside the target station, ignoring the collaboration between stops, this paper puts emphasis on joint passenger control methods during the occurrence of large passenger flows. To provide a theoretic description for the problem under consideration, an integer programming model is built, based on the analysis of passenger delay and the processes by which passengers alight and board. Taking average passenger delay as the objective, the proposed model aims to disperse the pressure of oversaturated stations into others, achieving the optimal state for the entire line. The model is verified using a case study and the results show that restricted access measures taken collaboratively by stations produce less delay and faster evacuation. Finally, a sensitivity analysis is conducted, from which we find that the departure interval and maximum conveying capacity of the train affect passenger delay markedly in the process of passenger control and infer that control measures should be taken at stations near to the one experiencing an emergency.

  17. 14 CFR 136.7 - Passenger briefings.

    Science.gov (United States)

    2010-01-01

    ... AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS COMMERCIAL AIR TOURS AND NATIONAL PARKS AIR TOUR MANAGEMENT National Air Tour Safety Standards § 136.7 Passenger briefings. (a)...

  18. 76 FR 23109 - Enhancing Airline Passenger Protections

    Science.gov (United States)

    2011-04-25

    ... in this pilot project to discover the best ways to use Web 2.0 and social networking technologies to... negative an impact on international passengers as they were already planning on spending a...

  19. Optimal boarding method for airline passengers

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Jason H.; /Fermilab

    2008-02-01

    Using a Markov Chain Monte Carlo optimization algorithm and a computer simulation, I find the passenger ordering which minimizes the time required to board the passengers onto an airplane. The model that I employ assumes that the time that a passenger requires to load his or her luggage is the dominant contribution to the time needed to completely fill the aircraft. The optimal boarding strategy may reduce the time required to board and airplane by over a factor of four and possibly more depending upon the dimensions of the aircraft. I explore some features of the optimal boarding method and discuss practical modifications to the optimal. Finally, I mention some of the benefits that could come from implementing an improved passenger boarding scheme.

  20. Ecological model of extinctions

    CERN Document Server

    Abramson, G

    1997-01-01

    We present numerical results based on a simplified ecological system in evolution, showing features of extinction similar to that claimed for the biosystem on Earth. In the model each species consists of a population in interaction with the others, that reproduces and evolves in time. Each species is simultaneously a predator and a prey in a food chain. Mutations that change the interactions are supposed to occur randomly at a low rate. Extinctions of populations result naturally from the predator-prey dynamics. The model is not pinned in a fitness variable, and natural selection arises from the dynamics.

  1. Lactobacillus agilis is an important component of the pigeon crop flora.

    Science.gov (United States)

    Baele, M; Devriese, L A; Haesebrouck, F

    2001-09-01

    To examine the presence of lactic acid bacteria (LAB: enterococci, streptococci and lactobacilli) in the pigeon crop. The crops of 10 pigeons were sampled and inoculated on agar plates for isolation of streptococci, enterococci and lactobacilli. The isolates were identified using tDNA-PCR. Lactobacillus agilis, a species described in 1981 from municipal sewage, was the dominant component in eight of these pigeon crop sacs. A Lactobacillus species related to L. fermentum and L. mucosae but probably not belonging to one of these species was isolated from five birds. Three pigeons carried Enterococcus cecorum. Minor species found were E. columbae, E. faecalis, E. hirae, L. johnsonii, L. salivarius, and Streptococcus gallolyticus. A description is given of the phenotypic characteristics of the L. agilis pigeon strains. L. agilis is found to be the main component of the LAB flora in the pigeon crop.

  2. Approaches to Czech Passenger Railway Market Liberalisation

    OpenAIRE

    Tomeš Zdeněk; Jandová Monika

    2016-01-01

    Competition on the Czech railway passenger market has been developing recently. It is possible to distinguish two types of competition – unregulated competition (competition on the market) and regulated competition (competition for the market). Competition on the market is present on the Prague–Ostrava route and competition for the market has been applied in a few public tenders for subsidised services. However, the substantial part of the Czech railway passenger market has remained closed an...

  3. Discovering Family Groups in Passenger Social Networks

    Institute of Scientific and Technical Information of China (English)

    万怀宇; 王志伟; 林友芳; 贾旭光; 周元炜

    2015-01-01

    People usually travel together with others in groups for different purposes, such as family members for visiting relatives, colleagues for business, friends for sightseeing and so on. Especially, the family groups, as a kind of the most com-mon consumer units, have a considerable scale in the field of passenger transportation market. Accurately identifying family groups can help the carriers to provide passengers with personalized travel services and precise product recommendation. This paper studies the problem of finding family groups in the field of civil aviation and proposes a family group detection method based on passenger social networks. First of all, we construct passenger social networks based on their co-travel behaviors extracted from the historical travel records; secondly, we use a collective classification algorithm to classify the social relationships between passengers into family or non-family relationship groups; finally, we employ a weighted com-munity detection algorithm to find family groups, which takes the relationship classification results as the weights of edges. Experimental results on a real dataset of passenger travel records in the field of civil aviation demonstrate that our method can effectively find family groups from historical travel records.

  4. Level of service at airport passenger terminals

    Directory of Open Access Journals (Sweden)

    Tasić Tamara D.

    2016-01-01

    Full Text Available Airport terminals are designed by level of service standards which are regulated by International Air Transport Association (IATA. Level of service offered to passengers, regarding to the primary processes, is not necessarily equivalent to the level of service perceived by them. The fact that passengers spending longer times in terminals makes the secondary processes more important in passenger experience. Aiming to improving airport attractiveness, and business success, passenger perception is approached by paying close attention. This paper discusses the two aspects of level of service. Concept of level of service used in air traffic industry with purpose of designing and planning of passenger terminal is derived from the Highway Capacity Manual. Subject of the paper regards last changes which have been introduced during 2014. Second part of the paper explains the needs of examining and analyzing passenger perception from the management point of view, and gives overview of methods which are conducted during researches. Similarities and differences are shown among measurements of level of service and perceived level of service, including the importance of these aspects mutual complementing.

  5. Presumed "prefrontal cortex" lesions in pigeons : effects on visual discrimination performance

    OpenAIRE

    Aldavert-Vera, Laura; Costa-Miserachs, David; Divac, Ivan; Delius, Juan

    1999-01-01

    The posterodorsolateral neostriatum (PDLNS) in pigeons may be an equivalent of the prefrontal cortex (PFC) in mammals. Here we report that lesions of this brain region in pigeons have a detrimental effect on various learned visual discriminations. Pigeons with lesions of the overlying area corticoidea dorsolateralis (CDL) served as controls. Both the postoperative re-learning to criterion of a preoperatively learned simultaneous double visual mirror pattern discrimination and the learning of ...

  6. GROWTH, INSTABILITY AND FORECASTING OF PIGEON PEA, CHICKPEA AND FIELD PEA PULSE PRODUCTION IN BANGLADESH

    OpenAIRE

    Rahman, Niaz Md. Farhat; Imam, M. F.

    2008-01-01

    The study tried to find out the appropriate models using latest model selection criteria that could describe the best growth pattern of pigeon pea, chickpea and field pea pulse production. The study also tried to measure the instability, growth rates of pigeon pea, chickpea and field pea pulse production and to determine the efficient time series models, to forecast the future pigeon pea, chickpea and field pea pulse production in Bangladesh. Forecasting attempts have been made to achieve the...

  7. Alcohol Fuel in Passenger Car

    Directory of Open Access Journals (Sweden)

    Adam Polcar

    2016-01-01

    Full Text Available The present article studies the effects of combustion of high-percentage mixture of bioethanol and gasoline on the output parameters of a passenger car engine. The car engine has not been structurally modified for the combustion of fuels with higher ethanol content. The mixture used consisted of E85 summer blend and Natural 95 gasoline in a ratio of 50:50. The parameters monitored during the experiment included the air-fuel ratio in exhaust gasses, the power output and torque of the engine and also the specific energy consumption and efficiency of the engine. As is apparent from the results, E85+N95 (50:50 mixture combustion results in lean-burn (λ > 1 due to the presence of oxygen in bioethanol. The lean-burn led to a slight decrease in torque and power output of the engine. However, due to the positive physicochemical properties of bioethanol, the decrease has not been as significant as would normally be expected from the measured air-fuel ratio. These findings are further confirmed by the calculated energy required to produce 1 kWh of energy, and by the higher efficiency of the engine during the combustion of a 50% bioethanol mixture.

  8. Context, Learning, and Extinction

    Science.gov (United States)

    Gershman, Samuel J.; Blei, David M.; Niv, Yael

    2010-01-01

    A. Redish et al. (2007) proposed a reinforcement learning model of context-dependent learning and extinction in conditioning experiments, using the idea of "state classification" to categorize new observations into states. In the current article, the authors propose an interpretation of this idea in terms of normative statistical inference. They…

  9. Unexpectedly many extinct hominins.

    Science.gov (United States)

    Bokma, Folmer; van den Brink, Valentijn; Stadler, Tanja

    2012-09-01

    Recent studies indicate that Neanderthal and Denisova hominins may have been separate species, while debate continues on the status of Homo floresiensis. The decade-long debate between "splitters," who recognize over 20 hominin species, and "lumpers," who maintain that all these fossils belong to just a few lineages, illustrates that we do not know how many extinct hominin species to expect. Here, we present probability distributions for the number of speciation events and the number of contemporary species along a branch of a phylogeny. With estimates of hominin speciation and extincton rates, we then show that the expected total number of extinct hominin species is 8, but may be as high as 27. We also show that it is highly unlikely that three very recent species disappeared due to natural, background extinction. This may indicate that human-like remains are too easily considered distinct species. Otherwise, the evidence suggesting that Neanderthal and the Denisova hominin represent distinct species implies a recent wave of extinctions, ostensibly driven by the only survivor, H. sapiens. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  10. Training reinforcement rates, resistance to extinction, and the role of context in reinstatement.

    Science.gov (United States)

    Miranda-Dukoski, Ludmila; Bensemann, Joshua; Podlesnik, Christopher A

    2016-03-01

    Behavior reduced as a consequence of extinction or intervention can relapse. According to behavioral momentum theory, the extent to which behavior persists and relapses once it has been eliminated depends on the relative training reinforcement rate among discriminative stimuli. In addition, studies of context renewal reveal that relapse depends on the similarity between the training stimulus context and the test stimulus context following disruption by extinction. In the present experiments with pigeons, we arranged different reinforcement rates in the presence of distinct discriminative stimuli across components of a multiple schedule. Following extinction, we attempted to reinstate responding in the presence of those target components with response-independent food presentations. Importantly, we arranged the reinstating food presentations either within the target components or in separate components, either paired with extinction (Experiment 1) or reinforcement (Experiment 2) during baseline. Reinstatement increased with greater training reinforcement rates when the reinstating food presentations were arranged in the target components and the separate components paired with reinforcement during training. Reinstatement was smaller and was not systematically related to training reinforcement rates in the target components when reinstating food presentation occurred in separate components paired with extinction. These findings suggest that relapse depends on the history of reinforcement associated with the discriminative stimuli in which the relapse-inducing event occurs.

  11. Effect of Hygromycin-B on pigeons (Columba livia) with and without Trichomonas gallinae

    Science.gov (United States)

    Kocan, R.M.

    1972-01-01

    Hygromycin-B was administered in varied quantities to pigeons harboring nonvirulent Trichomonas gallinae and to pigeons free of T. gallinae. Both groups responded identically with large yellow caseous lesions in the upper digestive tract which superficially resembled canker (trichomoniasis). No mycotic association with the lesions could be established in either .group from sections stained with periodic acid-Schiff. The lesions observed in Hygromycin-B-treated pigeons were concluded to be the direct result of the drug on the mucosa of the pigeon's upper digestive tract.

  12. Ecology: Dynamics of Indirect Extinction.

    Science.gov (United States)

    Montoya, Jose M

    2015-12-01

    The experimental identification of the mechanism by which extinctions of predators trigger further predator extinctions emphasizes the role of indirect effects between species in disturbed ecosystems. It also has deep consequences for the hidden magnitude of the current biodiversity crisis.

  13. Mathematical modelling and research of passenger flows in marine passenger port

    Directory of Open Access Journals (Sweden)

    Vladimir A. Fetisov

    2017-03-01

    Full Text Available Modern passenger terminals are characterized by dynamic processes variability, diverse options consideration, taking into account the criteria of safety, reliability analysis and the continuous research of passenger processing. For any modern marine passenger terminal it is necessary to use the tool to simulate passenger flows. In this way it is possible to obtain the analytical information and use it for decision-making when solving the problem of the amount of personnel required for passenger services.in line with the original ship arrival schedule, to solve problems of forecasting groups at the terminal. Of particular relevance is the choice of the mathematical transport model and the practical conditions for the implementation of the model in the real terminal operation. In this article the analysis technique of simulation-based terminal services, provides a mathematical model of passenger movement inside the terminal. Also, the conditions of implementation of the transportation model during the operation of marine passenger terminal are examined. The object of the research is the marine Passenger Port of St. Petersburg "Marine Facade". The paper discusses advantages of using such systems and their introduction in the early stages of operation of the terminal. In addition, the conclusion about the effectiveness of such systems for the analysis of the correctness of internal space of the marine terminal. The study represents an example of analytical information used for the forecast of the terminal operations, the analysis of the workload and efficiency of the organization of the marine terminal.

  14. Mass Extinctions Past and Present.

    Science.gov (United States)

    Allmon, Warren Douglas

    1987-01-01

    Discusses some parallels that seem to exist between mass extinction recognizable in the geologic record and the impending extinction of a significant proportion of the earth's species due largely to tropical deforestation. Describes some recent theories of causal factors and periodicities in mass extinction. (Author/TW)

  15. Evaluation of Pigeon Pea Lines for Biological Soil Decompaction

    Directory of Open Access Journals (Sweden)

    Rodolfo Godoy

    2009-01-01

    Full Text Available Soil decompaction is generally achieved through mechanical cultivation practices; however biological processes can significantly add to this process through root growth, development, and later senescence. This study was carried out in Piracicaba, SP, Brazil and had the purpose of selecting, among forty one pure pigeon pea lines, the most efficient genotypes that promote soil decompaction by roots penetrating compacted soil layers. Utilizing artificially compacted 30 mm high soil blocks, in a series of experiments, these lines were compared to the cultivar Fava Larga taken as a standard. Three lines were preliminarily selected out of the initial group, and afterwards, in more detailed screenings by monitoring soil resistance to penetration and also evaluating the behavior of Tanzania grass plants seeded after pigeon pea, two of them, g5-94 and g8-95, were selected as possessing the most fit root system to penetrate compacted soil layers.

  16. PIGEON PEA (Cajanus cajan AN ALTERNATIVE IN THE FOOD INDUSTRY

    Directory of Open Access Journals (Sweden)

    Carmen Lucia Navarro V

    2014-12-01

    Full Text Available Due to the current situation of inadequate nutrition in the population of many countries, including Colombia. Search sources rich in proteins and low-cost alternatives. The pigeon pea (Cajanus cajan is an important legume that contain a mo derate amount of protein, calories, vitamins and minerals, its use in foods is limited by the presence of anti-nutritional factors, which can be reduced or eliminated through the use of treatments. The proteins have functional properties that can be take advantage in meat, dairy and bakery products. The purpose of this review is to present an overview of the skills nutritional and functional properties of pigeon pea application opportunities in various applications in the food industry.

  17. Esophagitis and enteritis caused by herpesvirus in pigeons.

    Directory of Open Access Journals (Sweden)

    Egobol, L.

    2002-01-01

    Full Text Available The pigeon squabs, aged 5-26 day-old, showed clinical signs of dullness, anorexia, indigestion, reten-tion of feed in crop, progressive emaciation then died. The morbidity rate and mortality rate were 7.14% (50/700. The adult pigeons did not show any signs of disease. From pathological finding, pharyngitis, esophagitis were found with diphtheritic membrane covering necrotic ulcers on the mucosa of pharynx, esophagus and crop. From histopathological findings, esophagitis with epithelial hyperplasia and sloughed, lamina propria mucosa edema with lymphoid cells infiltration were found in duodenum and jejunum. The intranuclear inclusion body, Cowdry type A, was found in epithelial mucosa of esophagus, enterocyte of jejunum and lymphoid cells in spleen. FA test to duck virus enteritis and inoculation to ducklings showed negative results. Electron microscopic study revealed electron dense core sized 146-167 nm., which was identified as herpesvirus.

  18. Reciprocal relationships in collective flights of homing pigeons

    CERN Document Server

    Xu, Xiao-Ke; Small, Michael

    2011-01-01

    Collective motion of bird flocks can be explained via the hypothesis of many wrongs, and/or, a structured leadership mechanism. In pigeons, previous studies have shown that there is a well-defined hierarchical structure and certain specific individuals occupy more dominant positions --- suggesting that leadership by the few individuals drives the behavior of the collective. Conversely, by analyzing the same data-sets, we uncover a more egalitarian mechanism. We show that both reciprocal relationships and a stratified hierarchical leadership are important and necessary in the collective movements of pigeon flocks. Rather than birds adopting either exclusive averaging or leadership strategies, our experimental results show that it is an integrated combination of both compromise and leadership which drives the group's movement decisions.

  19. Self-control in pigeons under the Mischel paradigm

    Science.gov (United States)

    Grosch, James; Neuringer, Allen

    1981-01-01

    Walter Mischel studied self-control in preschool children in the following manner: if the child waited for an interval to end, he or she received the more preferred of two reinforcers; if the child responded to terminate the interval by ringing a bell, the less preferred reinforcer was given. We used an analogous procedure to study self-control in pigeons: if the bird waited for a trial to end, it received the more preferred reinforcer; if the bird terminated the trial by pecking a key, the less preferred reinforcer was given. We explored the effects on self-control of a number of variables analogous to those studied by Mischel and co-workers, e.g., presence versus absence of reinforcers, of alternative responses, and of stimuli during the wait interval; prior experience of the subjects; and test paradigm. The results obtained with pigeons paralleled the results obtained by Mischel with human children. PMID:16812197

  20. Substitution effects in a generalized token economy with pigeons.

    Science.gov (United States)

    Andrade, Leonardo F; Hackenberg, Timothy D

    2017-01-01

    Pigeons made repeated choices between earning and exchanging reinforcer-specific tokens (green tokens exchangeable for food, red tokens exchangeable for water) and reinforcer-general tokens (white tokens exchangeable for food or water) in a closed token economy. Food and green food tokens could be earned on one panel; water and red water tokens could be earned on a second panel; white generalized tokens could be earned on either panel. Responses on one key produced tokens according to a fixed-ratio schedule, whereas responses on a second key produced exchange periods, during which all previously earned tokens could be exchanged for the appropriate commodity. Most conditions were conducted in a closed economy, and pigeons distributed their token allocation in ways that permitted food and water consumption. When the price of all tokens was equal and low, most pigeons preferred the generalized tokens. When token-production prices were manipulated, pigeons reduced production of the tokens that increased in price while increasing production of the generalized tokens that remained at a fixed price. The latter is consistent with a substitution effect: Generalized tokens increased and were exchanged for the more expensive reinforcer. When food and water were made freely available outside the session, token production and exchange was sharply reduced but was not eliminated, even in conditions when it no longer produced tokens. The results join with other recent data in showing sustained generalized functions of token reinforcers, and demonstrate the utility of token-economic methods for assessing demand for and substitution among multiple commodities in a laboratory context.

  1. When one hemisphere takes control: metacontrol in pigeons (Columba livia.

    Directory of Open Access Journals (Sweden)

    Ruth Adam

    Full Text Available BACKGROUND: Vertebrate brains are composed of two hemispheres that receive input, compute, and interact to form a unified response. How the partially different processes of both hemispheres are integrated to create a single output is largely unknown. In some cases one hemisphere takes charge of the response selection--a process known as metacontrol. Thus far, this phenomenon has only been shown in a handful of studies with primates, mostly conducted in humans. Metacontrol, however, is even more relevant for animals like birds with laterally placed eyes and complete chiasmatic decussation since visual input to the hemispheres is largely different. METHODOLOGY/PRINCIPAL FINDINGS: Homing pigeons (Columba livia were trained with a color discrimination task. Each hemisphere was trained with a different color pair and therefore had a different experience. Subsequently, the pigeons were binocularly examined with two additional stimuli that combined the positive color of one hemisphere with a negative color that had been shown to the other, omitting the availability of a coherent solution and confronting the pigeons with a conflicting situation. Some of the pigeons responded to both stimuli, indicating that none of the hemispheres dominated the overall preference. Some birds, however, responded primarily to one of the conflicting stimuli, showing that they based their choice on the left- or right-monocularly learned color pair, indicating hemispheric metacontrol. CONCLUSIONS/SIGNIFICANCE: We could demonstrate for the first time that metacontrol is a widespread phenomenon that also exists in birds, and thus in principle requires no corpus callosum. Our results are closely similar to those in humans: monocular performance was higher than binocular one and animals displayed different modes of hemispheric dominance. Thus, metacontrol is a dynamic and widely distributed process that possibly constitutes a requirement for all animals with a bipartite brain to

  2. Necrotizing hepatitis in a domestic pigeon (Columba livia).

    Science.gov (United States)

    Himmel, L; O'Connor, M; Premanandan, C

    2014-11-01

    An adult male domestic pigeon (Columba livia) was presented for necropsy following natural death after a period of chronic weight loss and severe intestinal ascariasis. Histopathologic examination of the liver found moderate to marked, multifocal necrotizing hepatitis with large, basophilic intranuclear inclusion bodies. Transmission electron microscopy of affected hepatocytes demonstrated numerous intra- and perinuclear icosahedral virions arranged in a lattice structure, consistent with adenoviral infection.

  3. Contingency adduction of “symbolic aggression” by pigeons

    OpenAIRE

    Andronis, Paul Thomas; Layng, T.V. Joe; Goldiamond, Israel

    1997-01-01

    This study addressed the question: Can novel social behavior arise even though the organism has had no explicit training in that particular social pattern? Seven pigeons were trained individually to peck keys for brief access to food. Four of these birds were also trained to peck two “switching keys” which, at first, raised or lowered the requirements on their own food keys. Later, these switching keys no longer affected an animal's own requirements, but raised or lowered the requirements imp...

  4. Geochemistry and hydrology of perched groundwater springs: assessing elevated uranium concentrations at Pigeon Spring relative to nearby Pigeon Mine, Arizona (USA)

    Science.gov (United States)

    Beisner, Kimberly R.; Paretti, Nicholas; Tillman, Fred; Naftz, David L.; Bills, Donald; Walton-Day, Katie; Gallegos, Tanya J.

    2017-01-01

    The processes that affect water chemistry as the water flows from recharge areas through breccia-pipe uranium deposits in the Grand Canyon region of the southwestern United States are not well understood. Pigeon Spring had elevated uranium in 1982 (44 μg/L), compared to other perched springs (2.7–18 μg/L), prior to mining operations at the nearby Pigeon Mine. Perched groundwater springs in an area around the Pigeon Mine were sampled between 2009 and 2015 and compared with material from the Pigeon Mine to better understand the geochemistry and hydrology of the area. Two general groups of perched groundwater springs were identified from this study; one group is characterized by calcium sulfate type water, low uranium activity ratio 234U/238U (UAR) values, and a mixture of water with some component of modern water, and the other group by calcium-magnesium sulfate type water, higher UAR values, and radiocarbon ages indicating recharge on the order of several thousand years ago. Multivariate statistical principal components analysis of Pigeon Mine and spring samples indicate Cu, Pb, As, Mn, and Cd concentrations distinguished mining-related leachates from perched groundwater springs. The groundwater potentiometric surface indicates that perched groundwater at Pigeon Mine would likely flow toward the northwest away from Pigeon Spring. The geochemical analysis of the water, sediment and rock samples collected from the Snake Gulch area indicate that the elevated uranium at Pigeon Spring is likely related to a natural source of uranium upgradient from the spring and not likely related to the Pigeon Mine.

  5. Geochemistry and hydrology of perched groundwater springs: assessing elevated uranium concentrations at Pigeon Spring relative to nearby Pigeon Mine, Arizona (USA)

    Science.gov (United States)

    Beisner, Kimberly R.; Paretti, Nicholas V.; Tillman, Fred D.; Naftz, David L.; Bills, Donald J.; Walton-Day, Katie; Gallegos, Tanya J.

    2017-03-01

    The processes that affect water chemistry as the water flows from recharge areas through breccia-pipe uranium deposits in the Grand Canyon region of the southwestern United States are not well understood. Pigeon Spring had elevated uranium in 1982 (44 μg/L), compared to other perched springs (2.7-18 μg/L), prior to mining operations at the nearby Pigeon Mine. Perched groundwater springs in an area around the Pigeon Mine were sampled between 2009 and 2015 and compared with material from the Pigeon Mine to better understand the geochemistry and hydrology of the area. Two general groups of perched groundwater springs were identified from this study; one group is characterized by calcium sulfate type water, low uranium activity ratio 234U/238U (UAR) values, and a mixture of water with some component of modern water, and the other group by calcium-magnesium sulfate type water, higher UAR values, and radiocarbon ages indicating recharge on the order of several thousand years ago. Multivariate statistical principal components analysis of Pigeon Mine and spring samples indicate Cu, Pb, As, Mn, and Cd concentrations distinguished mining-related leachates from perched groundwater springs. The groundwater potentiometric surface indicates that perched groundwater at Pigeon Mine would likely flow toward the northwest away from Pigeon Spring. The geochemical analysis of the water, sediment and rock samples collected from the Snake Gulch area indicate that the elevated uranium at Pigeon Spring is likely related to a natural source of uranium upgradient from the spring and not likely related to the Pigeon Mine.

  6. Geochemistry and hydrology of perched groundwater springs: assessing elevated uranium concentrations at Pigeon Spring relative to nearby Pigeon Mine, Arizona (USA)

    Science.gov (United States)

    Beisner, Kimberly R.; Paretti, Nicholas V.; Tillman, Fred D.; Naftz, David L.; Bills, Donald J.; Walton-Day, Katie; Gallegos, Tanya J.

    2016-11-01

    The processes that affect water chemistry as the water flows from recharge areas through breccia-pipe uranium deposits in the Grand Canyon region of the southwestern United States are not well understood. Pigeon Spring had elevated uranium in 1982 (44 μg/L), compared to other perched springs (2.7-18 μg/L), prior to mining operations at the nearby Pigeon Mine. Perched groundwater springs in an area around the Pigeon Mine were sampled between 2009 and 2015 and compared with material from the Pigeon Mine to better understand the geochemistry and hydrology of the area. Two general groups of perched groundwater springs were identified from this study; one group is characterized by calcium sulfate type water, low uranium activity ratio 234U/238U (UAR) values, and a mixture of water with some component of modern water, and the other group by calcium-magnesium sulfate type water, higher UAR values, and radiocarbon ages indicating recharge on the order of several thousand years ago. Multivariate statistical principal components analysis of Pigeon Mine and spring samples indicate Cu, Pb, As, Mn, and Cd concentrations distinguished mining-related leachates from perched groundwater springs. The groundwater potentiometric surface indicates that perched groundwater at Pigeon Mine would likely flow toward the northwest away from Pigeon Spring. The geochemical analysis of the water, sediment and rock samples collected from the Snake Gulch area indicate that the elevated uranium at Pigeon Spring is likely related to a natural source of uranium upgradient from the spring and not likely related to the Pigeon Mine.

  7. Mathematical analysis of the navigational process in homing pigeons.

    Science.gov (United States)

    Schiffner, Ingo; Baumeister, Johann; Wiltschko, Roswitha

    2011-12-21

    In a novel approach based on the principles of dynamic systems theory, we analyzed the tracks of pigeons recorded with the help of miniaturized GPS recorders. Using the method of time lag embedding, we calculated the largest Lyapunov exponent to determine the system's predictability and the correlation dimension to estimate the number of factors involved. A low Lyapunov exponent around 0.02, which proved to be rather constant over all calculations, indicates that the navigational process is almost deterministic. In the distribution of the correlation dimension estimates we found three distinctive peaks, at 3.3, 3.7 and 4.2, indicating that avian navigation is a complex multi-dimensional process, involving at least four or five independent factors. Additional factors, as indicated by an increase in the correlation dimension, seem to be included as the pigeons approach their home loft. This increase in correlation dimension and its fractal nature suggest that the various navigational factors can be included as required and weighted independently. Neither the correlation dimension nor the Lyapunov exponent is affected by increasing familiarity of the pigeons with the terrain. This suggests that the navigational strategy is stable with the same process controlling the flight across familiar as well as unfamiliar terrain.

  8. Detection and discrimination of complex sounds by pigeons (Columba livia).

    Science.gov (United States)

    Cook, Robert G; Qadri, Muhammad A J; Oliveira, Ryan

    2016-02-01

    Auditory scene analysis is the process by which sounds are separated and identified from each other and from the background to make functional auditory objects. One challenge in making these psychological units is that complex sounds often continuously differ in composition over their duration. Here we examined the acoustic basis of complex sound processing in four pigeons by evaluating their performance in an ongoing same/different (S/D) task. This provided an opportunity to investigate avian auditory processing in a non-vocal learning, non-songbird. These pigeons were already successfully discriminating 18.5 s sequences of all different 1.5 s sounds (ABCD…) from sequences of one sound repeating (AAAA…, BBBB…, etc.) in a go/no-go procedure. The stimuli for these same/different sequences consisted of 504 tonal sounds (36 chromatic notes×14 different instruments), 36 pure tones, and 72 complex sounds. Not all of these sounds were equally effective in supporting S/D discrimination. As identified by a stepwise regression modeling of ten acoustic properties, tonal and complex sounds with intermediate levels of acoustic content tended to support better discrimination. The results suggest that pigeons have the auditory and cognitive capabilities to recognize and group continuously changing sound elements into larger functional units that can serve to differentiate long sequences of same and different sounds.

  9. Personality and morphological traits affect pigeon survival from raptor attacks.

    Science.gov (United States)

    Santos, Carlos D; Cramer, Julia F; Pârâu, Liviu G; Miranda, Ana C; Wikelski, Martin; Dechmann, Dina K N

    2015-10-22

    Personality traits have recently been shown to impact fitness in different animal species, potentially making them similarly relevant drivers as morphological and life history traits along the evolutionary pathways of organisms. Predation is a major force of natural selection through its deterministic effects on individual survival, but how predation pressure has helped to shape personality trait selection, especially in free-ranging animals, remains poorly understood. We used high-precision GPS tracking to follow whole flocks of homing pigeons (Columba livia) with known personalities and morphology during homing flights where they were severely predated by raptors. This allowed us to determine how the personality and morphology traits of pigeons may affect their risk of being predated by raptors. Our survival model showed that individual pigeons, which were more tolerant to human approach, slower to escape from a confined environment, more resistant to human handling, with larger tarsi, and with lighter plumage, were more likely to be predated by raptors. We provide rare empirical evidence that the personality of prey influences their risk of being predated under free-ranging circumstances.

  10. Two-level leader-follower organization in pigeon flocks

    Science.gov (United States)

    Chen, Zhiyong; Zhang, Hai-Tao; Chen, Xi; Chen, Duxin; Zhou, Tao

    2015-10-01

    The most attractive trait of collective animal behavior is the emergence of highly ordered structures (Cavagna A., Giardina I. and Ginelli F., Phys. Rev. Lett., 110 (2013) 168107). It has been conjectured that the interaction mechanism in pigeon flock dynamics follows a hierarchical leader-follower influential network (Nagy M., Ákos Z., Biro D. and Vicsek T., Nature, 464 (2010) 890). In this paper, a new observation is reported that shows that pigeon flocks actually adopt a much simpler two-level interactive network composed of one leader and some followers. By statistically analyzing the same experimental dataset, we show that for a certain period of time a sole leader determines the motion of the flock while the remaining birds are all followers directly copying the leader's direction with specific time delays. This simple two-level despotic organization is expected to save both motional energy and communication cost, while retaining agility and robustness of the whole group. From an evolutionary perspective, our results suggest that a two-level organization of group flight may be more efficient than a multilevel topology for small pigeon flocks.

  11. Less means more for pigeons but not always.

    Science.gov (United States)

    Zentall, Thomas R; Laude, Jennifer R; Case, Jacob P; Daniels, Carter W

    2014-12-01

    When humans are asked to judge the value of a set of objects of excellent quality, they often give this set higher value than those same objects with the addition of some of lesser quality. This is an example of the affect heuristic, often referred to as the less-is-more effect. Monkeys and dogs, too, have shown this suboptimal effect. But in the present experiments, normally hungry pigeons chose optimally: a preferred food plus a less-preferred food over a more-preferred food alone. In Experiment 2, however, pigeons on a less-restricted diet showed the suboptimal less-is-more effect. Choice on control trials indicated that the effect did not result from the novelty of two food items versus one. The effect in the less-food-restricted pigeons appears to result from the devaluation of the combination of the food items by the presence of the less-preferred food item. The reversal of the effect under greater food restriction may occur because, as motivation increases, the value of the less-preferred food increases faster than the value of the more-preferred food, thus decreasing the difference in value between the two foods.

  12. Modeling passenger flows in public transport stations

    Directory of Open Access Journals (Sweden)

    Cem Kırlangıçoğlu

    2015-06-01

    Full Text Available There are many architectural design parameters for public transport stations which include urban and station level studies. Each station must be designed in accordance with the basic passenger requirements such as accessibility, safety, comfort, satisfaction and etc. Circulation spaces must be formed and sized to meet the minimum movement needs of passengers. For an underground station; main entrance region, position of gates, location and number of turnstiles, escalators, stairs, ramps, passageways, intermediate concourses and platforms must be arranged to minimize walking distances and to prevent congestion. In this study, circulation of passengers is simulated in a quantitatively verifiable manner, taking into account how individuals interact with each other and with the physical obstacles in their environment in a metro station. Virtual experiments are performed to see the continuity and density of pedestrian flow at different levels of Haram Area East Metro Station of the first metro line of Madinah Al-Munawwarah, Saudi Arabia. According to the predictions, more than 40.000 passengers are expected to use this station in one hour after a Friday prayer during Ramadan period in the year of 2040. That means a critically high travel demand and it is really significant to design the most convenient underground station for these passengers to fulfil the necessary requirements.

  13. Neuronal circuits of fear extinction.

    Science.gov (United States)

    Herry, Cyril; Ferraguti, Francesco; Singewald, Nicolas; Letzkus, Johannes J; Ehrlich, Ingrid; Lüthi, Andreas

    2010-02-01

    Fear extinction is a form of inhibitory learning that allows for the adaptive control of conditioned fear responses. Although fear extinction is an active learning process that eventually leads to the formation of a consolidated extinction memory, it is a fragile behavioural state. Fear responses can recover spontaneously or subsequent to environmental influences, such as context changes or stress. Understanding the neuronal substrates of fear extinction is of tremendous clinical relevance, as extinction is the cornerstone of psychological therapy of several anxiety disorders and because the relapse of maladaptative fear and anxiety is a major clinical problem. Recent research has begun to shed light on the molecular and cellular processes underlying fear extinction. In particular, the acquisition, consolidation and expression of extinction memories are thought to be mediated by highly specific neuronal circuits embedded in a large-scale brain network including the amygdala, prefrontal cortex, hippocampus and brain stem. Moreover, recent findings indicate that the neuronal circuitry of extinction is developmentally regulated. Here, we review emerging concepts of the neuronal circuitry of fear extinction, and highlight novel findings suggesting that the fragile phenomenon of extinction can be converted into a permanent erasure of fear memories. Finally, we discuss how research on genetic animal models of impaired extinction can further our understanding of the molecular and genetic bases of human anxiety disorders.

  14. Genomic diversity and evolution of the head crest in the rock pigeon

    DEFF Research Database (Denmark)

    Shapiro, Michael D.; Kronenberg, Zev; Li, Cai;

    2013-01-01

    The geographic origins of breeds and the genetic basis of variation within the widely distributed and phenotypically diverse domestic rock pigeon (Columba livia) remain largely unknown. We generated a rock pigeon reference genome and additional genome sequences representing domestic and feral pop...

  15. [The experimental investigations upon the influence of ocular fixation on habituation of postural reflexes in pigeon].

    Science.gov (United States)

    Kaźmierczak, H

    1994-01-01

    The subject of investigation was the influence of ocular fixation on acquisition of habituation in experimental rotatory test in pigeons. The habituation training was performed in the three difference conditions: with full ocular fixation, fixation partly reduced and fixation excluded. Author confirmed that habituation with fixation excluded gave the best results of habituation of postural reflexes and head nystagmus in pigeons in rotatory training.

  16. Ontogeny and localization of γ-crystallin antigen in the developing pigeon (Columba livia) lens

    NARCIS (Netherlands)

    Brahma, S.K.; Rabaey, M.; Doorenmaalen, W.J. van

    Ontogeny and localization of the lens γ-crystallin antigen were investigated in the embryonic and post-embryonic pigeon lenses by the indirect immunofluorescence with antiserum from rabbit immunized with isolated pigeon lens γ-crystallin. The results show that γ-crystallin appears for the first time

  17. Newcastle disease B1 vaccine strain in wild rock pigeons in Atlanta, Georgia

    Science.gov (United States)

    From June to October of 2012, samples were collected from wild Rock Pigeons (Columba livia) in urban neighborhoods of Atlanta, Georgia to ascertain the prevalence of pigeon paramyxovirus serotype-1 (PPMV-1). PPMV-1 strains are a subset of avian paramyxovirus serotype-1 (APMV-1) commonly isolated fro...

  18. Ontogeny and localization of γ-crystallin antigen in the developing pigeon (Columba livia) lens

    NARCIS (Netherlands)

    Brahma, S.K.; Rabaey, M.; Doorenmaalen, W.J. van

    1972-01-01

    Ontogeny and localization of the lens γ-crystallin antigen were investigated in the embryonic and post-embryonic pigeon lenses by the indirect immunofluorescence with antiserum from rabbit immunized with isolated pigeon lens γ-crystallin. The results show that γ-crystallin appears for the first time

  19. Blood characteristics, microbial and gastrointestinal parasites of street pigeons (Columba Livia in Owerri Imo State, Nigeria

    Directory of Open Access Journals (Sweden)

    M. N. Opara

    2012-07-01

    Full Text Available The study was conducted to determine the haematological and biochemical indices and the naturally occurring haemo and gastrointestinal microbes of 150 matured street pigeons in Owerri, Imo State, Nigeria. The PCV, WBC, MCV, MCH and total bilirubin values of the female pigeons were significantly (p0.05 between the two group. Out of 150 street pigeons examined for prevalence of parasites, 70 (46.70% of them were infected with gastro-intestinal parasites of which 30 (42.93% were males and 40 (57.1% were females. Four gastro-intestinal parasites were identified with Trichomonas sp. giving the highest prevalence rate (42%, followed by Eimeria sp. (28%, and whereas Coccidia sp. and Ascaridia sp. returned the least with each having the prevalence rate of (14%. Results of haemo -parasitological examination of thin blood smears revealed haematozoa of two genera: Haemoproteus sp. which was more common gave a prevalence rate of 40 (66% for the male and 70 (87% for the female pigeons. Plasmodium sp. with prevalence of 20 (33% and 10 (12% in male and female pigeons respectively. Fecal cultures recorded high growth of bacterial organisms, of which Proteus sp. returned 50 (83% and Enterococcus sp. returned 10 (16%. In totality, 40% of the pigeons had bacterial infections. In conclusion, the prevalence of gastrointestinal and haemoparasites in street pigeons in Owerri, Imo State, Nigeria. However, these parasites did not cause any visible deleterious effects in the blood parameters of the pigeons examined.

  20. Pre-lithification structures, deformation mechanisms, and fabric ellipsoids in slumped turbidites from the Pigeon Point Formation, California

    Science.gov (United States)

    Paterson, Scott R.; Tobisch, Othmar T.

    1993-06-01

    Paterson, S.R. and Tobisch, O.T. 1993. Pre-lithification structures, deformation mechanisms, and fabric ellipsoids in slumped turbidites from the Pigeon Point Formation, California. Tectonophysics, 222: 135-149. Quantitative fabric, structural, and microstructural analyses of pre-lithification folds, foliations, and lineations formed by slumping of turbidite sequences in the Cretaceous Pigeon Point Formation, California, provide a useful comparison with strain and microstructures developed in lithified and tectonically deformed turbidites. Our results indicate the following: (1) multiple generations of folds, cleavages, and lineations can develop prior to any post-lithification tectonic deformation (2) individual grains in sandstones have variable axial ratios, but the ratios and orientations of large populations of grains define fabric ellipsoids with small axial ratios ( ave. = 1.25:1.13:1) (3) phyllosilicate grains define moderate flattening fabrics (reflecting 20-40% shortening or volume loss), with the intensity of alignment partly controlled by the percent of quartz and feldspar grains (4) the fabric ellipsoids in sand-rich layers largely reflect deposition and slumping: pre- and post-slump compactions did not occur, in sand-rich units but did align clay particles in mud-siltstone units, and (5) intra-grain microstructures in quartz and feldspar (e.g., undulose extinction, subgrains) are inherited or recycled features rather than representing effects of post-lithification strains. Our data also suggest that prelithification slumping occurred by pervasive grain rotation and grain boundary sliding in saturated sands with some local movement of material along bedding horizons. A likely model for the folding and associated fabrics is that buckling and fold-hinge flattening drove fluid expulsion, which in turn caused local grain-scale realignment, transposition of bedding, and the development of an axial planar cleavage in the hinge zones. Continued fluid flow was

  1. High Prevalence and Genetic Diversity of Campylobacter jejuni in Wild Crows and Pigeons.

    Science.gov (United States)

    Ramonaitė, Sigita; Novoslavskij, Aleksandr; Zakarienė, Gintarė; Aksomaitienė, Jurgita; Malakauskas, Mindaugas

    2015-11-01

    The occurrence, seasonal variation and genetic diversity of Campylobacter spp. in pigeons and crows over a 1-year period were evaluated. Campylobacter spp. were isolated from 166 (34.6 %) out of 480 wild bird faecal samples. The occurrence of Campylobacter spp. in faecal samples was higher among crows (39.2 %) than pigeons (30.0 %), (P Campylobacter jejuni was the most common species detected among wild bird faecal samples (98.2 %). Meanwhile, Campylobacter coli prevalence in wild bird faecal samples was low-6 %. The Simpson's diversity index of C. jejuni flaA RFLP types was lower in pigeons (D = 0.88) compared with C. jejuni isolates detected in crows (D = 0.97). Obtained results revealed that C. jejuni are widely prevalent among crows and pigeons, indicating these wild birds as potential infection sources to humans. Further studies are required to determine crows and pigeons role in zoonotic transmission of Campylobacter.

  2. Hypothetical superparamagnetic magnetometer in a pigeon's upper beak probably does not work.

    Science.gov (United States)

    Jandačka, Petr; Alexa, Petr; Pištora, Jaromír; Trojková, Jana

    2013-04-01

    We reanalysed the role of superparamagnetic magnetite clusters observed in a pigeon's upper beak to decide if this matter can be a component of some sort of pigeon magnetometer for Earth orientation. We investigated the mutual interaction of the magnetite clusters induced by the geomagnetic field. The force sensitivity of the hypothetical magnetometer in a pigeon's upper beak was estimated considering the previously presented threshold magnetic sensitivity of pigeons, measured in electrophysiological and behavioural investigations. The typical intercluster magnetic force seems to be 10(-19)N well above the threshold magnetic sensitivity. To strengthen our results, we measured the magnetic susceptibility of superparamagnetic magnetite using a vibrating sample magnetometer. Finally we performed theoretical kinematic analysis of the motion of magnetite clusters in cell plasma. The results indicate that magnetite clusters, constituted by superparamagnetic nanoparticles and observed in a pigeon's upper beak, may not be a component of a measuring system providing the magnetic map.

  3. The complete mitochondrial genome of the ice pigeon (Columba livia breed ice).

    Science.gov (United States)

    Zhang, Rui-Hua; He, Wen-Xiao

    2015-02-01

    The ice pigeon is a breed of fancy pigeon developed over many years of selective breeding. In the present work, we report the complete mitochondrial genome sequence of ice pigeon for the first time. The total length of the mitogenome was 17,236 bp with the base composition of 30.2% for A, 24.0% for T, 31.9% for C, and 13.9% for G and an A-T (54.2 %)-rich feature was detected. It harbored 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and 1 non-coding control region (D-loop region). The arrangement of all genes was identical to the typical mitochondrial genomes of pigeon. The complete mitochondrial genome sequence of ice pigeon would serve as an important data set of the germplasm resources for further study.

  4. The complete mitochondrial genome of the Fancy Pigeon, Columba livia (Columbiformes: Columbidae).

    Science.gov (United States)

    Zhang, Rui-Hua; Xu, Ming-Ju; Wang, Cun-Lian; Xu, Tong; Wei, Dong; Liu, Bao-Jian; Wang, Guo-Hua

    2015-02-01

    The fancy pigeons are domesticated varieties of the rock pigeon developed over many years of selective breeding. In the present work, we report the complete mitochondrial genome sequence of fancy pigeon for the first time. The total length of the mitogenome was 17,233 bp with the base composition of 30.1% for A, 24.0% for T, 31.9% for C, and 14.0% for G and an A-T (54.2 %)-rich feature was detected. It harbored 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and 1 non-coding control region (D-loop region). The arrangement of all genes was identical to the typical mitochondrial genomes of pigeon. The complete mitochondrial genome sequence of fancy pigeon would serve as an important data set of the germplasm resources for further study.

  5. Molecular characterization of Cryptosporidium spp. in domestic pigeons (Columba livia domestica) in Guangdong Province, Southern China.

    Science.gov (United States)

    Li, Juan; Lin, Xuhui; Zhang, Longxian; Qi, Nanshan; Liao, Shenquan; Lv, Minna; Wu, Caiyan; Sun, Mingfei

    2015-06-01

    To investigate the prevalence and assess the zoonotic transmission burden of Cryptosporidium species in domestic pigeons in Guangdong Province, Southern China, 244 fecal samples were collected from four pigeon breeding farms between June 2012 and March 2013. Cryptosporidium oocysts were purified by Sheather's sugar flotation technique and characterized by DNA sequencing of small subunit ribosomal RNA (SSU rRNA) gene. Cryptosporidium species were determined by comparison of sequences with corresponding Cryptosporidium sequences in GenBank and phylogenetic analysis using neighbor-joining (NJ) in MEGA5.2. The overall prevalence of Cryptosporidium infection in domestic pigeons in Guangdong Province was 0.82% (2/244). Two Cryptosporidium species, namely Cryptosporidium baileyi and Cryptosporidium meleagridis, were identified in Huizhou and Chaozhou farm, respectively. These findings confirmed the existence of C. meleagridis infection in domestic pigeons in China for the first time and provided base-line information for further studies to evaluate the public health risk from pigeon to human.

  6. Characterization of the complete mitochondrial genome of the king pigeon (Columba livia breed king).

    Science.gov (United States)

    Zhang, Rui-Hua; He, Wen-Xiao; Xu, Tong

    2015-06-01

    The king pigeon is a breed of pigeon developed over many years of selective breeding primarily as a utility breed. In the present work, we report the complete mitochondrial genome sequence of king pigeon for the first time. The total length of the mitogenome was 17,221 bp with the base composition of 30.14% for A, 24.05% for T, 31.82% for C, and 13.99% for G and an A-T (54.22 %)-rich feature was detected. It harbored 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and one non-coding control region (D-loop region). The arrangement of all genes was identical to the typical mitochondrial genomes of pigeon. The complete mitochondrial genome sequence of king pigeon would serve as an important data set of the germplasm resources for further study.

  7. THE PROBLEMS OF PASSENGER TRANSPORTATIONS IN AN INTERNATIONAL COMMUNICATION

    Directory of Open Access Journals (Sweden)

    Yu. S. Barash

    2010-05-01

    Full Text Available The basic aspects of international passenger transportations in Ukraine are represented. The analysis of present situation in these transportations is carried out. Some variants of solving the problems of passenger transportations in an international communication are considered.

  8. Economic Impact of Cruise Ship Passengers in Bar Harbor, Maine

    OpenAIRE

    Gabe, Todd; Lynch, Colleen; McConnon, James; Allen, Thomas

    2003-01-01

    This report examines the economic impact of cruise ship passengers in Bar Harbor, Maine. In 2002, 64 cruise ships docked in Bar Harbor carrying about 120,000 passengers and crewmembers. The analysis presented in the report is based on 1,080 passenger surveys conducted between August and October of 2002. Economic impact figures are based on a total of 97,190 passengers, which is the capacity of the 64 cruise ships that were scheduled to visit Bar Harbor in 2002.

  9. The Impact of Deoxynivalenol on Pigeon Health: Occurrence in Feed, Toxicokinetics and Interaction with Salmonellosis

    Science.gov (United States)

    Devreese, Mathias; Broekaert, Nathan; Verbrugghe, Elin; De Saeger, Sarah; Audenaert, Kris; Haesebrouck, Freddy; Pasmans, Frank; Ducatelle, Richard; Croubels, Siska; Martel, An

    2016-01-01

    Seed-based pigeon diets could be expected to result in exposure of pigeons to mycotoxins such as deoxynivalenol (DON). Ingestion of low to moderate contamination levels of DON may impair intestinal health, immune function and/or pathogen fitness, resulting in altered host-pathogen interactions and thus different outcome of infections. Here we demonstrate that DON was one of the most frequently detected mycotoxins in seed-based racing pigeons feed, contaminating 5 out of 10 samples (range 177–1,466 μg/kg). Subsequently, a toxicokinetic analysis revealed a low absolute oral bioavailability (F) of DON in pigeons (30.4%), which is comparable to other avian species. Furthermore, semi-quantitative analysis using high-resolution mass spectrometry revealed that DON-3α-sulphate is the major metabolite of DON in pigeons after intravenous as well as oral administration. Following ingestion of DON contaminated feed, the intestinal epithelial cells are exposed to significant DON concentrations which eventually may affect intestinal translocation and colonization of bacteria. Feeding pigeons a DON contaminated diet resulted in an increased percentage of pigeons shedding Salmonella compared to birds fed control diet, 87 ± 17% versus 74 ± 13%, respectively. However, no impact of DON was observed on the Salmonella induced disease signs, organ lesions, faecal and organ Salmonella counts. The presented risk assessment indicates that pigeons are frequently exposed to mycotoxins such as DON, which can affect the outcome of a Salmonella infection. The increasing number of pigeons shedding Salmonella suggests that DON can promote the spread of the bacterium within pigeon populations. PMID:27997572

  10. A magnetic pulse does not affect homing pigeon navigation: a GPS tracking experiment.

    Science.gov (United States)

    Holland, Richard; Filannino, Caterina; Gagliardo, Anna

    2013-06-15

    The cues by which homing pigeons are able to return to a home loft after displacement to unfamiliar release sites remain debated. A number of experiments in which migratory birds have been treated with a magnetic pulse have produced a disruption in their orientation, which argues that a ferrimagnetic sense is used for navigation in birds. One previous experiment has also indicated an effect of magnetic pulses on homing pigeon navigation, although with inconsistent results. Previous studies have shown that some magnetic-related information is transmitted by the trigeminal nerve to the brain in some bird species, including the homing pigeon. The function of this information is still unclear. It has been suggested that this information is important for navigation. Previous studies with trigeminal nerve lesioned homing pigeons have clearly shown that the lack of trigeminally mediated information, even if magnetic, is not crucial for homing performance. However, this result does not completely exclude the possibility that other ferrimagnetic receptors in the homing pigeon play a role in navigation. Additionally, recent studies on homing pigeons suggested the existence of a ferrimagnetic sense in a novel location presumably located in the inner ear (lagena). In the present study, we tested whether any ferrimagnetic magnetoreceptors, irrespective of their location in the bird's head, are involved in pigeons' homing. To do this, we treated homing pigeons with a strong magnetic pulse before release, tracked birds with GPS loggers and analyzed whether this treatment affected homing performance. In the single previous magnetic pulse experiment on homing pigeons, only initial orientation at a release site was considered and the results were inconsistent. We observed no effect of the magnetic pulse at any of the sites used on initial orientation, homing performance, tortuosity or track efficiency, which does not support a role for the ferrimagnetic sense in homing pigeon

  11. 49 CFR 541.5 - Requirements for passenger motor vehicles.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Requirements for passenger motor vehicles. 541.5... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR VEHICLE THEFT PREVENTION STANDARD § 541.5 Requirements for passenger motor vehicles. (a) Each passenger motor vehicle subject...

  12. 14 CFR 135.113 - Passenger occupancy of pilot seat.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Passenger occupancy of pilot seat. 135.113... Operations § 135.113 Passenger occupancy of pilot seat. No certificate holder may operate an aircraft type certificated after October 15, 1971, that has a passenger seating configuration, excluding any pilot seat,...

  13. Rescheduling of Railway Rolling Stock with Dynamic Passenger Flows

    NARCIS (Netherlands)

    L.G. Kroon (Leo); G. Maróti (Gábor); L.K. Nielsen (Lars Kjaer)

    2010-01-01

    textabstractTraditional rolling stock rescheduling applications either treat passengers as static objects whose influence on the system is unchanged in a disrupted situation, or they treat passenger behavior as a given input. In case of disruptions however, we may expect the flow of passengers to

  14. Modelling expected train passenger delays on large scale railway networks

    DEFF Research Database (Denmark)

    Landex, Alex; Nielsen, Otto Anker

    2006-01-01

    Forecasts of regularity for railway systems have traditionally – if at all – been computed for trains, not for passengers. Relatively recently it has become possible to model and evaluate the actual passenger delays by a passenger regularity model for the operation already carried out. First...

  15. Simulating disturbances and modelling expected train passenger delays

    DEFF Research Database (Denmark)

    Landex, Alex; Nielsen, Otto Anker

    2006-01-01

    Forecasts of regularity for railway systems have traditionally – if at all – been computed for trains, not for passengers. It has only relatively recently become possible to model and evaluate the actual passenger delays. This paper describes how it is possible to use a passenger regularity model...

  16. Extinction Events Can Accelerate Evolution

    DEFF Research Database (Denmark)

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific......Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate...... evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending...

  17. Extinction events can accelerate evolution.

    Directory of Open Access Journals (Sweden)

    Joel Lehman

    Full Text Available Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific in the long term.

  18. Extinction Events Can Accelerate Evolution

    Science.gov (United States)

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    Extinction events impact the trajectory of biological evolution significantly. They are often viewed as upheavals to the evolutionary process. In contrast, this paper supports the hypothesis that although they are unpredictably destructive, extinction events may in the long term accelerate evolution by increasing evolvability. In particular, if extinction events extinguish indiscriminately many ways of life, indirectly they may select for the ability to expand rapidly through vacated niches. Lineages with such an ability are more likely to persist through multiple extinctions. Lending computational support for this hypothesis, this paper shows how increased evolvability will result from simulated extinction events in two computational models of evolved behavior. The conclusion is that although they are destructive in the short term, extinction events may make evolution more prolific in the long term. PMID:26266804

  19. A Passenger Travel Demand Model for Copenhagen

    DEFF Research Database (Denmark)

    Overgård, Christian Hansen; Jovicic, Goran

    2003-01-01

    The passenger travel model for Copenhagen is a state-of-practice nested logit model in which the sub-models - i.e. generation, distribution and mode choice models - are connected via measure of accessibility. The model includes in its structure a large set of explanatory variables at all three...

  20. 75 FR 36300 - Enhancing Airline Passenger Protections

    Science.gov (United States)

    2010-06-25

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Office of the Secretary 14 CFR Parts 234, 244, 250,253, 259, and 399 RIN 2105-AD92 Enhancing Airline... Airline Passenger Protections (75 FR 32318), which, among other things, solicits comment, without...

  1. Serviceability of passenger trains during acquisition projects

    NARCIS (Netherlands)

    Parada Puig, Jorge Eduardo

    2015-01-01

    Acquiring assets that can be serviced cost effectively is a fundamental goal during large acquisition projects at NS, the largest railway company in the Netherlands. Buying passenger trains and providing their required services requires important strategic decisions involving both the trains and the

  2. Disruption Management in Passenger Railway Transportation

    DEFF Research Database (Denmark)

    Groth, Julie Jespersen; Potthoff, Daniel; Clausen, Jens

    2009-01-01

    This paper deals with disruption management in passenger railway transportation. In the disruption management process, many actors belonging to different organizations play a role. In this paper we therefore describe the process itself and the roles of the different actors. Furthermore, we discuss...

  3. Serviceability of passenger trains during acquisition projects

    NARCIS (Netherlands)

    Parada Puig, J.E.

    2015-01-01

    Acquiring assets that can be serviced cost effectively is a fundamental goal during large acquisition projects at NS, the largest railway company in the Netherlands. Buying passenger trains and providing their required services requires important strategic decisions involving both the trains and

  4. Polyandry prevents extinction.

    Science.gov (United States)

    Price, Tom A R; Hurst, Greg D D; Wedell, Nina

    2010-03-09

    Females of most animal species are polyandrous, with individual females usually mating with more than one male. However, the ubiquity of polyandry remains enigmatic because of the potentially high costs to females of multiple mating. Current theory to account for the high prevalence of polyandry largely focuses on its benefits to individual females. There are also higher-level explanations for the high incidence of polyandry-polyandrous clades may speciate more rapidly. Here we test the hypothesis that polyandry may also reduce population extinction risk. We demonstrate that mating with multiple males protects populations of the fruit fly Drosophila pseudoobscura against extinction caused by a "selfish" sex-ratio-distorting element. Thus, the frequency of female multiple mating in nature may be associated not only with individual benefits to females of this behavior but also with increased persistence over time of polyandrous species and populations. Furthermore, we show that female remating behavior can determine the frequency of sex-ratio distorters in populations. This may also be true for many other selfish genetic elements in natural populations.

  5. Avian toxoplasmosis: experimental infection of chicken and pigeon.

    Science.gov (United States)

    Biancifiori, F; Rondini, C; Grelloni, V; Frescura, T

    1986-01-01

    Two groups of 13 new-laying hens each were infected by crop-route with 5000 and 50,000 infective oocysts of T. gondii. Four groups of 5 pigeons each were inoculated by crop-route with 50, 500, 1000 and 5000 infective oocysts. To each group of infected birds suitable controls were added. Hens from the experiment with 5000 infective oocysts were apparently resistant to the infection and they had no clinical signs in the succeeding 40 days p.i. Hens from the experiment with 50,000 infective oocysts showed an egg-drop and mortality in embryonated eggs, especially during the first 2 weeks p.i. Isolation of the parasite was unsuccessfully attempted from 720 embryonated eggs, produced by infected groups, and tested on various days p.i. and at different stages of infection. The parasite was isolated from the brain, heart, liver, spleen and lung of infected birds 7 and 15 days p.i.; 40 days p.i. it was evident only in brain and heart. IgG onset and mean course were monitored by ELISA and high titers were reached by both groups. Pigeons from groups 500, 1000 and 5000 developed rapidly progressive clinical signs as diarrhea, trembling, incoordination, torticollis and death. They had enlargement of liver and spleen and focal necrosis, nodular features in the crop. Pigeons from expt 50 had no clinical signs in spite of the presence of the parasite in their organs for over 45 days p.i. Parasite was isolated from brain, heart, liver, spleen, lung, kidney, crop and muscles from all infected groups. Histopathological and ultrastructural features revealed the presence of multiplying tachizoites even within cells of the crop. Seroconversion, as monitored by ELISA, was recorded in all infected groups although high ELISA-titres were never reached. One of the negative controls from expt 5000 developed specific antibodies but the parasite was not isolated from its organs.

  6. Route following and the pigeon's familiar area map.

    Science.gov (United States)

    Guilford, Tim; Biro, Dora

    2014-01-15

    Homing pigeons (Columba livia) have been the central model of avian navigation research for many decades, but only more recently has research extended into understanding their mechanisms of orientation in the familiar area. The discovery (facilitated by GPS tracking) that pigeons gradually acquire with experience individually idiosyncratic routes home to which they remain faithful on repeated releases, even if displaced off-route, has helped uncover the fundamental role of familiar visual landmarks in the avian familiar area map. We evaluate the robustness and generality of the route-following phenomenon by examining extant studies in depth, including the single published counter-example, providing a detailed comparison of route efficiencies, flight corridor widths and fidelity. We combine this analysis with a review of inferences that can be drawn from other experimental approaches to understanding the nature of familiar area orientation in pigeons, including experiments on landmark recognition, and response to clock-shift, to build the first detailed picture of how bird orientation develops with experience of the familiar area. We articulate alternative hypotheses for how guidance might be controlled during route following, concluding that although much remains unknown, the details of route following strongly support a pilotage interpretation. Predictable patterns of efficiency increase, but limited to the local route, typical corridor widths of 100-200 m, high-fidelity pinch-points on route, attraction to landscape edges, and a robustness to clock-shift procedures, all demonstrate that birds can associatively acquire a map of their familiar area guided (at least partially) by direct visual control from memorised local landscape features.

  7. Stress-induced core temperature changes in pigeons (Columba livia).

    Science.gov (United States)

    Bittencourt, Myla de Aguiar; Melleu, Fernando Falkenburger; Marino-Neto, José

    2015-02-01

    Changes in body temperature are significant physiological consequences of stressful stimuli in mammals and birds. Pigeons (Columba livia) prosper in (potentially) stressful urban environments and are common subjects in neurobehavioral studies; however, the thermal responses to stress stimuli by pigeons are poorly known. Here, we describe acute changes in the telemetrically recorded celomatic (core) temperature (Tc) in pigeons given a variety of potentially stressful stimuli, including transfer to a novel cage (ExC) leading to visual isolation from conspecifics, the presence of the experimenter (ExpR), gentle handling (H), sham intracelomatic injections (SI), and the induction of the tonic immobility (TI) response. Transfer to the ExC cage provoked short-lived hyperthermia (10-20 min) followed by a long-lasting and substantial decrease in Tc, which returned to baseline levels 2 h after the start of the test. After a 2-hour stay in the ExC, the other potentially stressful stimuli evoked only weak, marginally significant hyperthermic (ExpR, IT) or hypothermic (SI) responses. Stimuli delivered 26 h after transfer to the ExC induced definite and intense increases in Tc (ExpR, H) or hypothermic responses (SI). These Tc changes appear to be unrelated to modifications in general activity (as measured via telemetrically recorded actimetric data). Repeated testing failed to affect the hypothermic responses to the transference to the ExC, even after nine trials and at 1- or 8-day intervals, suggesting that the social (visual) isolation from conspecifics may be a strong and poorly controllable stimulus in this species. The present data indicated that stress-induced changes in Tc may be a consistent and reliable physiological parameter of stress but that they may also show stressor type-, direction- and species-specific attributes.

  8. Respiratory water loss in free-flying pigeons.

    Science.gov (United States)

    Michaeli, G; Pinshow, B

    2001-11-01

    We assessed respiratory and cutaneous water loss in trained tippler pigeons (Columba livia) both at rest and in free flight. In resting pigeons, exhaled air temperature T(ex) increased with ambient air temperature T(a) (T(ex)=16.3+0.705T(a)) between 15 degrees C and 30 degrees C, while tidal volume V(T) (V(T)=4.7+/-1.0 ml, mean +/- S.D. at standard temperature and pressure dry) and breathing frequency f(R) (f(R)=0.46+/-0.06 breaths s(-1)) were independent of T(a). Respiratory water loss, RWL, was constant over the range of T(a) (RWL=1.2+/-0.4 mg g(-1) h(-1)) used. In flying pigeons, T(ex) increased with T(a) (T(ex)=25.8+0.34T(a)), while f(R) was independent of T(a) (f(R)=5.6+/-1.4 breaths s(-1)) between 8.8 degrees C and 27 degrees C. Breathing frequency varied intermittently between 2 and 8 breaths s(-1) during flight and was not always synchronized with wing-beat frequency. RWL was independent of air temperature (RWL=9.2+/-2.9 mg g(-1) h(-1)), but decreased with increasing inspired air water vapor density (rho(in)) (RWL=12.5-0.362rho(in)), whereas cutaneous water loss, CWL, increased with air temperature (CWL=10.122+0.898T(a)), but was independent of rho(in). RWL was 25.7-32.2 %, while CWL was 67.8-74.3 % of the total evaporative water loss. The data indicate that pigeons have more efficient countercurrent heat exchange in their anterior respiratory passages when at rest than in flight, allowing them to recover more water at rest at lower air temperatures. When evaporative water loss increases in flight, especially at high T(a), the major component is cutaneous rather than respiratory, possibly brought about by reducing the skin water vapor diffusion resistance. Because of the tight restrictions imposed by gas exchange in flight, the amount of water potentially lost through respiration is limited.

  9. Modeling and Simulation of Virtual Clay Pigeon shooter Training System

    Directory of Open Access Journals (Sweden)

    Jin Yanxia

    2013-10-01

    Full Text Available As a popular sports event, clay pigeon uses real guns and bullets as its tools. To improve the training effect, reduce its cost and danger, the development of a real-time interactive and perceptive virtual training system by using simulation technology becomes urgent. This system uses Visual C++、Vega、Creator as its development platform to conduct modeling and simulation of clay pigeon’s and grapeshot ‘s flying path and the collision effect of the two objects.  

  10. Spontaneous Atherosclerosis in Free-Living Pigeons in Mosul Area, Iraq

    Directory of Open Access Journals (Sweden)

    Hahfidh I. Al-Sadi* and Ashraf K. Abdullah

    2011-04-01

    Full Text Available The purpose of this study was to investigate for the first time the prevalence and pathology of spontaneous atherosclerosis in free – living pigeons in Mosul, Iraq. A hundred apparently healthy, 1-1.5 year old both sex pigeons of local breed free – living used. Effects of factors such as weight, sex, age and health status on prevalence of the condition were also studied. Prevalence of naturally occurring atherosclerosis was 10%. Grossly, the heart was hypertrophied and of firm consistency, aorta and coronary arteries were prominent and cordlike with thickened walls. Microscopically, lipid – laden "foam cells" were seen throughout the thickened tunica media and intima. Damage of the elastic lamellae and hypertrophy of the smooth muscle cells were also noted. Spontaneous atherosclerosis occurred more frequently in old pigeons. No effect was found for sex, weight, and health status of the pigeons on prevalence and pathology of spontaneous atherosclerosis. It was concluded that spontaneous atherosclerosis is fairly common in local pigeons and it occurred more commonly in old pigeons. Sex, weight, and health status of the pigeons did not constitute risk factors for the occurrence of spontaneous atherosclerosis.

  11. Detection of Neospora caninum-DNA in brain tissues from pigeons in Changchun, Jilin (China).

    Science.gov (United States)

    Du, Ling; Yang, Dongsheng; Zhai, Tao; Gong, Pengtao; Zhang, Xichen; Li, Jianhua

    2015-11-30

    Neospora caninum is an intracellular protozoan infecting many domestic and wild animals. The domestic chicken (Gallus domesticus) and the sparrow (Passer domesticus) are known as natural intermediate hosts of N. caninum, whereas the role of other birds such as pigeons is still unclear. In the present study, pigeon brain tissues collected in Jilin of China were screened by N. caninum specific-nested PCR to determine whether pigeons functioned as the natural intermediate hosts of N. caninum. The prevalences of N. caninum DNA and Toxoplasma gondii DNA among the brain samples were 30% (63/210) and 13.33% (28/210), respectively. One brain sample was co-infected with N. caninum and T. gondii in naturally infected pigeon. Of the 63 positive samples 42 could be assigned to the NC-PR genotype, 10 to the NC-1 genotypes and 5, 3 and 3 respectively to the each of the three new genotypes identified, indicating genetic polymorphism of N. caninum in pigeons in Jilin of China. The present study expanded the list of intermediate hosts of N. caninum to include pigeons which suggests that pigeons are involved in the transmission of the N. caninum.

  12. Reducing the availability of food to control feral pigeons: changes in population size and composition.

    Science.gov (United States)

    Senar, Juan C; Montalvo, Tomás; Pascual, Jordi; Peracho, Victor

    2017-02-01

    As feeding by humans is one of the main food resources to pigeons (Columba livia), there is general agreement that public education that aims to reduce the food base may be the most feasible way to reduce pigeon abundance. However, except for the classic example of Basel, the method has rarely been tested or implemented. We provide results from a 1 year study in the city of Barcelona where we tested the effect of public education on pigeon population abundance and composition. The quantity of food provided by people to pigeons was significantly reduced during the study. Feral pigeon density was reduced by 40% in the two experimental districts, but no variation was detected in the control district. Detailed analyses in one of the districts showed that the reduction was mainly related to the reduction in food availability but not to culling. Pigeons captured at the end of the experiment were larger than at the start of the study, but body condition was reduced. Results show the effectiveness of public information to manage feral pigeon populations in a large city, and that control operations can exert important selection pressure on the population, leading to changes in population composition. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  13. Introducing cultivated trees into the wild: Wood pigeons as dispersers of domestic olive seeds

    Science.gov (United States)

    Perea, Ramón; Gutiérrez-Galán, Alejandro

    2016-02-01

    Animals may disperse cultivated trees outside the agricultural land, favoring the naturalization or, even, the invasiveness of domestic plants. However, the ecological and conservation implications of new or unexplored mutualisms between cultivated trees and wild animals are still far from clear. Here, we examine the possible role of an expanding and, locally, overabundant pigeon species (Columba palumbus) as an effective disperser of domestic olive trees (Olea europaea), a widespread cultivated tree, considered a naturalized and invasive species in many areas of the world. By analyzing crop and gizzard content we found that olive fruits were an important food item for pigeons in late winter and spring. A proportion of 40.3% pigeons consumed olive seeds, with an average consumption of 7.8 seeds per pigeon and day. Additionally, most seed sizes (up to 0.7 g) passed undamaged through the gut and were dispersed from cultivated olive orchards to areas covered by protected Mediterranean vegetation, recording minimal dispersal distances of 1.8-7.4 km. Greenhouse experiments showed that seeds dispersed by pigeons significantly favored the germination and establishment in comparison to non-ingested seeds. The ability of pigeons to effectively disperse domestic olive seeds may facilitate the introduction of cultivated olive trees into natural systems, including highly-protected wild olive woodlands. We recommend harvesting ornamental olive trees to reduce both pigeon overpopulation and the spread of artificially selected trees into the natural environment.

  14. Genotypic and pathotypic characterization of Newcastle disease virus isolated from racing pigeons in China.

    Science.gov (United States)

    Liu, Mengda; Qu, Yajin; Wang, Fangkun; Liu, Sidang; Sun, Honglei

    2015-07-01

    A Newcastle disease virus (NDV) isolated from an outbreak in racing pigeons in China was characterized in this study. Complete gene of the NDV isolate was sequenced and phylogenetic analysis. Pathogenicity experiment was carried out in pigeons, chickens, and ducks. Phylogenetic analysis revealed that the strain clustered with the Class II viruses, has highly phylogenetically similar to NDV strains isolated from pigeons in China, but was distant from the viruses prevalence in chickens and vaccine strains used in China. The deduced amino acid sequence of the cleavage site of the fusion (F) protein confirmed that the isolate contained the virulent motif (112)RRQKRF(117) at the cleavage site, but it caused no appearance disease in chickens and ducks. However, the isolate had virulence in pigeons, resulting in severe nervous signs and highly mortality. Pigeons were considered as a potential source of NDV infection and disease for commercial poultry flocks. Therefore, new vaccines to prevent the NDV infection in the pigeon flocks should be developed as soon as possible, and strict biosecurity measures should be taken to reduce the risk of pigeon Newcastle disease outbreaks.

  15. Pigeons' (Columba livia) hierarchical organization of local and global cues in touch screen tasks.

    Science.gov (United States)

    Legge, Eric L G; Spetch, Marcia L; Batty, Emily R

    2009-02-01

    Redundant encoding of local and global spatial cues is a common occurrence in many species. However, preferential use of the each type of cue seems to vary across species and tasks. In the current study, pigeons (Columba livia) were trained in three experiments on a touch screen task which included redundant local positional cues and global spatial cues. Specifically, pigeons were required to choose the middle out of three choice squares, such that the position within the array provided local information and the location on the screen provided global information. In Experiment 1, pigeons were trained and tested on vertically aligned arrays. In Experiment 2, pigeons were trained and tested on horizontally aligned arrays, and in Experiment 3, pigeons were trained and tested with vertical, horizontal and diagonally aligned arrays. The results indicate that preference for cue type depends upon the type of spatial information being encoded. Specifically, on vertical and diagonally aligned arrays, pigeons preferred global cues, whereas on horizontally aligned arrays, pigeons preferred local cues.

  16. PREVALENCE OF TRICHOMONIASIS IN DOMESTIC AND WILD PIGEONS AND ITS EFFECTS ON HEMATOLOGICAL PARAMETERS

    Directory of Open Access Journals (Sweden)

    M. H. SALEEM, M. S. KHAN, A. S. CHAUDRY AND H. A. SAMAD

    2008-06-01

    Full Text Available The present study was conducted to determine the prevalence of trichomoniasis and its effect on some blood parameters in pigeons. A total of 100 samples from the pigeons (50 wild and 50 domestic were collected during the months of March and April 2005. Higher prevalence (P<0.05 was recorded in wild pigeons (60% than in domestic pigeon (26%. The overall prevalence recorded was 43%, being non significantly higher in April (56% than in March (30%. In infected pigeons, there was significant (P<0.05 decrease in hemoglobin concentration number of monocytes packed cell volume, body weight, than healthy birds. Likewise, the values of total leukocyte count, lymphocytes and eosinophils were higher significantly (P<0.05 in infected pigeons than the healthy ones. While, no significant difference was observed for heterophils count when infected and healthy birds were compared. It was concluded that trichomonad infection is quite common in wild, as well as in domestic, pigeons under the prevailing cage system.

  17. Cardiorespiratory responses to shivering in vagotomized pigeons during normoxia and hypoxia.

    Science.gov (United States)

    Gleeson, M; Barnas, G M; Rautenberg, W

    1986-12-01

    We measured respiratory, cardiovascular and blood gas responses to shivering during normoxia and hypoxia in five bilaterally, cervically vagotomized pigeons and compared these data with those previously reported in pigeons with intact vagi (Gleeson et al. 1986). Such neural section in birds denervates, among other receptors, the carotid bodies and intrapulmonary chemoreceptors. Normoxic breathing frequency (fR) and ventilation (VE) were decreased after vagotomy. Intact pigeons showed increases in oxygen consumption (VO2), tidal volume (VT), fR and VE during shivering. Vagotomized pigeons showed similar though slightly smaller increases in fR, VO2 and VE during shivering, but VT did not change. Normoxic heart rate was greater after vagotomy and was increased during shivering as in intact pigeons. Mean arterial blood pressure (MBPa) and stroke volume were not affected by vagotomy or shivering. At the onset of shivering both intact and vagotomized pigeons exhibited immediate increases in ventilation and heart rate. Exposure of vagotomized pigeons to hypoxic gas (fractional inspired oxygen concentration, FIO2 = 0.12) during cooling completely abolished shivering electromyogram (EMG) activity. In contrast, shivering in intact pigeons was not completely inhibited until the FIO2 fell below 0.10. We conclude that bilateral, cervical vagotomy in the pigeon causes hypoventilation and tachycardia during normoxia, but that these denervated birds are still able to rapidly effect cardiorespiratory adjustments to shivering. It is suggested that these responses are mediated mainly via afferent feedback from the shivering muscles. Hypoxia inhibits shivering in both intact and vagotomized birds and the mechanism is probably related to the reduced O2 delivery to the central structures that integrate thermoregulatory demand and coordinate appropriate responses.

  18. [Polymorphism and phene geography of the blue rock pigeon in Europe].

    Science.gov (United States)

    Obukhova, N Iu

    2007-05-01

    The variation of blue rock pigeon plumage color has been studied in 192 settlements of Europe. As in earlier studies, six color phenotypes have been distinguished, the main of which are blue, intermediate and melanistic. The phenotype frequency distribution patterns in urban and rural landscapes have been determined. Pigeon populations with increased density are the most melanistic. Rural populations are less melanistic than urban ones. The frequency of birds with aberrant plumage colors varies randomly and is increased in some localities. The phenotypic structure of synanthropic populations of the blue rock pigeon in Europe displays a latitudinal gradient.

  19. Thermochemical characterization of pigeon pea stalk for its efficient utilization as an energy source

    Energy Technology Data Exchange (ETDEWEB)

    Katyal, S.K.; Iyer, P.V.R.

    2000-05-01

    Pigeon pea stalk is a widely available biomass species in India. In this article the potential use of pigeon pea stalk as a fuel source through thermochemical conversion methods such as combustion, gasification, and pyrolysis has been investigated through experimentation using a thermogravimetric analyzer and pilot-plant-scale equipment. It has been proposed that pigeon pea stalks can be effectively utilized in two ways. The first is to pyrolyze the material to produce value-added products such as char, tar, and fuel gas. The second alternative is to partially pyrolyze the material to remove tar-forming volatiles, followed by gasification of reactive char to generate producer gas.

  20. A real-time PCR assay for the detection of atypical strains of Chlamydiaceae from pigeons.

    Directory of Open Access Journals (Sweden)

    Aleksandar Zocevic

    Full Text Available Recent evidence of the occurrence of atypical Chlamydiaceae strains in pigeons, different from the established Chlamydiaceae, requires the development of a specific and rapid detection tool to investigate their prevalence and significance. Here is described a new real-time PCR assay that allows specific detection of atypical Chlamydiaceae from pigeons. The assay has been used to assess the dissemination of these strains in field samples collected from Parisian pigeon populations in 2009. The results suggest a limited dissemination compared to the usually higher prevalence of Chlamydia psittaci that is the main species associated with avian chlamydiosis.

  1. Measuring Extinction with ALE

    Science.gov (United States)

    Zimmer, Peter C.; McGraw, J. T.; Gimmestad, G. G.; Roberts, D.; Stewart, J.; Smith, J.; Fitch, J.

    2007-12-01

    ALE (Astronomical LIDAR for Extinction) is deployed at the University of New Mexico's (UNM) Campus Observatory in Albuquerque, NM. It has begun a year-long testing phase prior deployment at McDonald Observatory in support of the CCD/Transit Instrument II (CTI-II). ALE is designed to produce a high-precision measurement of atmospheric absorption and scattering above the observatory site every ten minutes of every moderately clear night. LIDAR (LIght Detection And Ranging) is the VIS/UV/IR analog of radar, using a laser, telescope and time-gated photodetector instead of a radio transmitter, dish and receiver. In the case of ALE -- an elastic backscatter LIDAR -- 20ns-long, eye-safe laser pulses are launched 2500 times per second from a 0.32m transmitting telescope co-mounted with a 50mm short-range receiver on an alt-az mounted 0.67m long-range receiver. Photons from the laser pulse are scattered and absorbed as the pulse propagates through the atmosphere, a portion of which are scattered into the field of view of the short- and long-range receiver telescopes and detected by a photomultiplier. The properties of a given volume of atmosphere along the LIDAR path are inferred from both the altitude-resolved backscatter signal as well as the attenuation of backscatter signal from altitudes above it. We present ALE profiles from the commissioning phase and demonstrate some of the astronomically interesting atmospheric information that can be gleaned from these data, including, but not limited to, total line-of-sight extinction. This project is funded by NSF Grant 0421087.

  2. [Cloning of pigeon invariant chain (Ii) gene by RACE].

    Science.gov (United States)

    Liu, Gang; Zhong, Da-Lian; Liu, Xue-Lan; Yu, Wei-Yi

    2008-01-01

    In order to compare the structure and function of pigeon invariant chain (pIi) gene with other avian's, pIi gene was cloned using a method of RACE (Rapid Amplification of cDNA Ends). Firstly, according to high conservative nucleotide sequence of homologous fragment in avian invariant chain (Ii) gene, a pair of degenerated primer was designed, and a special DNA fragment was gained from pigeon spleen cell RNA by PCR. Then based on the sequence of gained DNA fragment, some new primers were designed, and the 3'terminal and the 5'terminal of pIi gene were cloned by RACE respectively. Finally a complete cDNA of pIi was to extend with newly designed primer by PCR. The product was identified by electrophresis and sequence analysis. The results of sequencing indicate that pIi gene is 1,050 bp in length (GenBank No. AY904337), which includes an open reading frame of 633 bp encoding a precursor protein with 211 amino acid residues. In comparison with the nucleotide sequences of other species' Ii genes, pIi is similar to chicken's, showing an overall identity of 82.8 with chicken and over 52.0 with human and other mammalian animals. In addition, some amino acid residues in Ii molecule manifest extremely conservative among animals, which suggests that they could have an important biological function.

  3. Preference for 50% reinforcement over 75% reinforcement by pigeons.

    Science.gov (United States)

    Gipson, Cassandra D; Alessandri, Jérôme J D; Miller, Holly C; Zentall, Thomas R

    2009-11-01

    When pigeons are given a choice between an initial-link alternative that results in either a terminal-link stimulus correlated with 100% reinforcement or a stimulus correlated with 0% reinforcement (overall 50% reinforcement) and another initial-link alternative that always results in a terminal-link stimulus correlated with 100% reinforcement, some pigeons show a preference for the initial-link alternative correlated with 50% reinforcement. Using this procedure, in Experiment 1, we found a relatively modest preference for 100% over 50% reinforcement. In Experiment 2, we decreased the reinforcement density for the second initial-link alternative to 75% and found a significant preference for the 50% reinforcement initial-link alternative. It may be that this "maladaptive" behavior results from a positive contrast between the expectation of reinforcement correlated with the 50% reinforcement initial-link alternative and the terminal-link stimulus correlated with 100% reinforcement. But apparently, the complementary negative contrast does not develop between the expectation of reinforcement correlated with the 50% reinforcement initial-link alternative and the terminal-link stimulus correlated with 0% reinforcement that often follow. Such paradoxical choice may account for certain human appetitive risk-taking behavior (e.g., gambling) as well.

  4. Functional organization of telencephalic visual association fields in pigeons.

    Science.gov (United States)

    Stacho, Martin; Ströckens, Felix; Xiao, Qian; Güntürkün, Onur

    2016-04-15

    Birds show remarkable visual abilities that surpass most of our visual psychophysiological abilities. In this study, we investigated visual associative areas of the tectofugal visual system in pigeons. Similar to the condition in mammals, ascending visual pathways in birds are subdivided into parallel form/color vs. motion streams at the thalamic and primary telencephalic level. However, we know practically nothing about the functional organization of those telencephalic areas that receive input from the primary visual telencephalic fields. The current study therefore had two objectives: first, to reveal whether these visual associative areas of the tectofugal system are activated during visual discrimination tasks; second, to test whether separated form/color vs. motion pathways can be discerned among these association fields. To this end, we trained pigeons to discriminate either form/color or motion stimuli and used the immediate early gene protein ZENK to capture the activity of the visual associative areas during the task. We could indeed identify several visual associative telencephalic structures by activity pattern changes during discriminations. However, none of these areas displayed a difference between form/color vs. motion sessions. The presence of such a distinction in thalamo-telencephalic, but not in further downstream visual association areas opens the possibility that these separate streams converge very early in birds, which possibly minimizes long-range connections due to the evolutionary pressure toward miniaturized brains.

  5. Genetic parameters of body weight and prolificacy in pigeons

    Directory of Open Access Journals (Sweden)

    Beaumont Catherine

    2000-07-01

    Full Text Available Abstract Genetic parameters of body weight at weaning and of prolificacy were estimated in three commercial lines of pigeons selected by BLUP (Best Linear Unbiased Prediction on both traits. The model of analysis took into account the direct genetic effects for both traits and the effect of parental permanent environment for body weight. Depending on the line considered, body weight varied from 556.7 g to 647.6 g and prolificacy ranged from 12.5 to 16.8 pigeons weaned per couple of parents per year. Heritability of body weight was high, varying between 0.46 and 0.60, and permanent environment was responsible for 6% to 9% of the total variability. On the contrary, prolificacy was poorly heritable (0.04 to 0.12. They were highly and negatively correlated (-0.77 to -0.82. Body weight showed significant genetic trends in lines B and C. No significant genetic difference could be observed between males and females for both traits.

  6. Dissemination of Salmonella enteritidis by experimentally-infected pigeons

    Directory of Open Access Journals (Sweden)

    ÁH Albuquerque

    2013-09-01

    Full Text Available Two groups of domestic pigeons (Columba livia were experimentally infected orally with doses of 9.5 x10(7 and 9.5 x10(9 CFU/mL (group A and B, respectively of a Salmonella Enteritidis (SE strain isolated from chickens. None of the used doses caused mortality of the inoculated birds; however, the pathogen was successfully recovered from the liver and spleen of group B birds on day 7 post-inoculation (dpi. Pathogen shedding, as evaluated through cloacal swabs, occurred in both groups until the 14th day of observation (p <0.05. Among all fecal samples collected from group B (n=4, three different birds shed the pathogen in their feces, out of which two were positive on 3 dpi and one on 7 dpi. The same number of fecal samples was evaluated in group A and only one bird shed the pathogen, on 7 and 14 dpi. The concentration of the microorganism in the feces was lower in group A than any sample from Group B. Salmonella Enteritidis isolated from chickens, when inoculated in pigeons, may be recovered from feces, cloacal swabs and organs, and these birds may contaminate poultry causing economic losses as well as posing a risk to the public health.

  7. Temporal and contextual consistency of leadership in homing pigeon flocks.

    Directory of Open Access Journals (Sweden)

    Carlos D Santos

    Full Text Available Organized flight of homing pigeons (Columba livia was previously shown to rely on simple leadership rules between flock mates, yet the stability of this social structuring over time and across different contexts remains unclear. We quantified the repeatability of leadership-based flock structures within a flight and across multiple flights conducted with the same animals. We compared two contexts of flock composition: flocks of birds of the same age and flight experience; and, flocks of birds of different ages and flight experience. All flocks displayed consistent leadership-based structures over time, showing that individuals have stable roles in the navigational decisions of the flock. However, flocks of balanced age and flight experience exhibited reduced leadership stability, indicating that these factors promote flock structuring. Our study empirically demonstrates that leadership and followership are consistent behaviours in homing pigeon flocks, but such consistency is affected by the heterogeneity of individual flight experiences and/or age. Similar evidence from other species suggests leadership as an important mechanism for coordinated motion in small groups of animals with strong social bonds.

  8. Speed Determines Leadership and Leadership Determines Learning during Pigeon Flocking.

    Science.gov (United States)

    Pettit, Benjamin; Ákos, Zsuzsa; Vicsek, Tamás; Biro, Dora

    2015-12-01

    A key question in collective behavior is how individual differences structure animal groups, affect the flow of information, and give some group members greater weight in decisions. Depending on what factors contribute to leadership, despotic decisions could either improve decision accuracy or interfere with swarm intelligence. The mechanisms behind leadership are therefore important for understanding its functional significance. In this study, we compared pigeons' relative influence over flock direction to their solo flight characteristics. A pigeon's degree of leadership was predicted by its ground speeds from earlier solo flights, but not by the straightness of its previous solo route. By testing the birds individually after a series of flock flights, we found that leaders had learned straighter homing routes than followers, as we would expect if followers attended less to the landscape and more to conspecifics. We repeated the experiment from three homing sites using multiple independent flocks and found individual consistency in leadership and speed. Our results suggest that the leadership hierarchies observed in previous studies could arise from differences in the birds' typical speeds. Rather than reflecting social preferences that optimize group decisions, leadership may be an inevitable consequence of heterogeneous flight characteristics within self-organized flocks. We also found that leaders learn faster and become better navigators, even if leadership is not initially due to navigational ability. The roles that individuals fall into during collective motion might therefore have far-reaching effects on how they learn about the environment and use social information.

  9. The end-Permian mass extinction: A complex, multicausal extinction

    Science.gov (United States)

    Erwin, D. H.

    1994-01-01

    The end-Permian mass extinction was the most extensive in the history of life and remains one of the most complex. Understanding its causes is particularly important because it anchors the putative 26-m.y. pattern of periodic extinction. However, there is no good evidence for an impact and this extinction appears to be more complex than others, involving at least three phases. The first began with the onset of a marine regression during the Late Permian and resulting elimination of most marine basins, reduction in habitat area, and increased climatic instability; the first pulse of tetrapod extinctions occurred in South Africa at this time. The second phase involved increased regression in many areas (although apparently not in South China) and heightened climatic instability and environmental degradation. Release of gas hydrates, oxidation of marine carbon, and the eruption of the Siberian flood basalts occurred during this phase. The final phase of the extinction episode began with the earliest Triassic marine regression and destruction of nearshore continental habitats. Some evidence suggests oceanic anoxia may have developed during the final phase of the extinction, although it appears to have been insufficient to the sole cause of the extinction.

  10. Functional similarities between pigeon 'milk' and mammalian milk: induction of immune gene expression and modification of the microbiota.

    Directory of Open Access Journals (Sweden)

    Meagan J Gillespie

    Full Text Available Pigeon 'milk' and mammalian milk have functional similarities in terms of nutritional benefit and delivery of immunoglobulins to the young. Mammalian milk has been clearly shown to aid in the development of the immune system and microbiota of the young, but similar effects have not yet been attributed to pigeon 'milk'. Therefore, using a chicken model, we investigated the effect of pigeon 'milk' on immune gene expression in the Gut Associated Lymphoid Tissue (GALT and on the composition of the caecal microbiota. Chickens fed pigeon 'milk' had a faster rate of growth and a better feed conversion ratio than control chickens. There was significantly enhanced expression of immune-related gene pathways and interferon-stimulated genes in the GALT of pigeon 'milk'-fed chickens. These pathways include the innate immune response, regulation of cytokine production and regulation of B cell activation and proliferation. The caecal microbiota of pigeon 'milk'-fed chickens was significantly more diverse than control chickens, and appears to be affected by prebiotics in pigeon 'milk', as well as being directly seeded by bacteria present in pigeon 'milk'. Our results demonstrate that pigeon 'milk' has further modes of action which make it functionally similar to mammalian milk. We hypothesise that pigeon 'lactation' and mammalian lactation evolved independently but resulted in similarly functional products.

  11. Functional Extinctions of Species in Ecological Networks

    OpenAIRE

    Säterberg, Torbjörn

    2016-01-01

    Current rates of extinctions are estimated to be around 1000 times higher than background rates that would occur without anthropogenic impacts. These extinction rates refer to the traditional view of extinctions, i.e. numerical extinctions. This thesis is about another type of extinctions: functional extinctions. Those occur when the abundance of a species is too small to uphold the species’ ecologically interactive role. I have taken a theoretical approach and used dynamical models to invest...

  12. Approaches to Czech Passenger Railway Market Liberalisation

    Directory of Open Access Journals (Sweden)

    Tomeš Zdeněk

    2016-02-01

    Full Text Available Competition on the Czech railway passenger market has been developing recently. It is possible to distinguish two types of competition – unregulated competition (competition on the market and regulated competition (competition for the market. Competition on the market is present on the Prague–Ostrava route and competition for the market has been applied in a few public tenders for subsidised services. However, the substantial part of the Czech railway passenger market has remained closed and there is a question how to proceed with the competition development – whether to promote competition on the market or competition for the market. Based on European and modelling experience, there is an argument for more competition for the market.

  13. Validating the passenger traffic model for Copenhagen

    DEFF Research Database (Denmark)

    Overgård, Christian Hansen; VUK, Goran

    2006-01-01

    The paper presents a comprehensive validation procedure for the passenger traffic model for Copenhagen based on external data from the Danish national travel survey and traffic counts. The model was validated for the years 2000 to 2004, with 2004 being of particular interest because the Copenhagen...... Metro became operational in autumn 2002. We observed that forecasts from the demand sub-models agree well with the data from the 2000 national travel survey, with the mode choice forecasts in particular being a good match with the observed modal split. The results of the 2000 car assignment model...... matched the observed traffic better than those of the transit assignment model. With respect to the metro forecasts, the model over-predicts metro passenger flows by 10% to 50%. The wide range of findings from the project resulted in two actions. First, a project was started in January 2005 to upgrade...

  14. Serviceability of passenger trains during acquisition projects

    OpenAIRE

    Parada Puig, J.E.

    2015-01-01

    Acquiring assets that can be serviced cost effectively is a fundamental goal during large acquisition projects at NS, the largest railway company in the Netherlands. Buying passenger trains and providing their required services requires important strategic decisions involving both the trains and their technical service system. This thesis studies how serviceability is considered during acquisition projects in practice, and explores means to support decisions that intend to improve serviceabil...

  15. Mass Extinctions in Earth's History

    Science.gov (United States)

    Ward, P. D.

    2002-12-01

    Mass extinctions are short intervals of elevated species death. Possible causes of Earth's mass extinctions are both external (astronomical) and internal (tectonic and biotic changes from planetary mechanisms). Paleontologists have identified five "major" mass extinctions (>50 die-off in less than a million years) and more than 20 other minor events over the past 550 million years. Earlier major extinction events undoubtedly also occurred, but we have no fossil record; these were probably associated with, for example, the early heavy bombardment that cleared out the solar system, the advent of oxygen in the atmosphere, and various "snowball Earth" events. Mass extinctions are viewed as both destructive (species death ) and constructive, in that they allow evolutionary innovation in the wake of species disappearances. From an astrobiological perspective, mass extinctions must be considered as able both to reduce biodiversity and even potentially end life on any planet. Of the five major mass extinctions identified on Earth, only one (the Cretaceous/Tertiary event 65 million years ago that famously killed off the dinosaurs ) is unambiguously related to the impact of an asteroid or comet ( 10-km diameter). The Permian/Triassic (250 Myr ago) and Triassic/Jurassic (202 Myr ago) events are now the center of debate between those favoring impact and those suggesting large volume flooding by basaltic lavas. The final two events, Ordovician (440 Myr ago) and Devonian (370 Myr ago) have no accepted causal mechanisms.

  16. The learning of fear extinction.

    Science.gov (United States)

    Furini, Cristiane; Myskiw, Jociane; Izquierdo, Ivan

    2014-11-01

    Recent work on the extinction of fear-motivated learning places emphasis on its putative circuitry and on its modulation. Extinction is the learned inhibition of retrieval of previously acquired responses. Fear extinction is used as a major component of exposure therapy in the treatment of fear memories such as those of the posttraumatic stress disorder (PTSD). It is initiated and maintained by interactions between the hippocampus, basolateral amygdala and ventromedial prefrontal cortex, which involve feedback regulation of the latter by the other two areas. Fear extinction depends on NMDA receptor activation. It is positively modulated by d-serine acting on the glycine site of NMDA receptors and blocked by AP5 (2-amino-5-phosphono propionate) in the three structures. In addition, histamine acting on H2 receptors and endocannabinoids acting on CB1 receptors in the three brain areas mentioned, and muscarinic cholinergic fibers from the medial septum to hippocampal CA1 positively modulate fear extinction. Importantly, fear extinction can be made state-dependent on circulating epinephrine, which may play a role in situations of stress. Exposure to a novel experience can strongly enhance the consolidation of fear extinction through a synaptic tagging and capture mechanism; this may be useful in the therapy of states caused by fear memory like PTSD.

  17. Estimating the surface area of birds: using the homing pigeon (Columba livia as a model

    Directory of Open Access Journals (Sweden)

    Cristina R. Perez

    2014-05-01

    Full Text Available Estimation of the surface area of the avian body is valuable for thermoregulation and metabolism studies as well as for assessing exposure to oil and other surface-active organic pollutants from a spill. The use of frozen carcasses for surface area estimations prevents the ability to modify the posture of the bird. The surface area of six live homing pigeons in the fully extended flight position was estimated using a noninvasive method. An equation was derived to estimate the total surface area of a pigeon based on its body weight. A pigeon's surface area in the fully extended flight position is approximately 4 times larger than the surface area of a pigeon in the perching position. The surface area of a bird is dependent on its physical position, and, therefore, the fully extended flight position exhibits the maximum area of a bird and should be considered the true surface area of a bird.

  18. Homing behavior of hippocampus and parahippocampus lesioned pigeons following short-distance releases.

    Science.gov (United States)

    Bingman, V P; Mench, J A

    1990-11-30

    The avian hippocampal formation has been proposed to play a critical role in the neural regulation of a navigational system used by homing pigeons to locate their loft once in the familiar area near home. In support of this hypothesis, the homing performance of pigeons with target lesions of either the hippocampus or parahippocampus was found to be impaired compared to controls following releases of about 10 km. Further, radio tracking revealed that the in-flight behavior of the hippocampal lesioned homing pigeons was characterized by numerous direction changes and generally poor orientation with respect to the home loft. The results identify a local navigational impairment on the part of the hippocampal lesioned pigeons in the vicinity of the loft where landmark cues are thought to be important. Additionally, target lesions of the hippocampus or parahippocampus were found to be similarly effective in causing homing deficits.

  19. Pigeon interaction mode switch-based UAV distributed flocking control under obstacle environments.

    Science.gov (United States)

    Qiu, Huaxin; Duan, Haibin

    2017-07-28

    Unmanned aerial vehicle (UAV) flocking control is a serious and challenging problem due to local interactions and changing environments. In this paper, a pigeon flocking model and a pigeon coordinated obstacle-avoiding model are proposed based on a behavior that pigeon flocks will switch between hierarchical and egalitarian interaction mode at different flight phases. Owning to the similarity between bird flocks and UAV swarms in essence, a distributed flocking control algorithm based on the proposed pigeon flocking and coordinated obstacle-avoiding models is designed to coordinate a heterogeneous UAV swarm to fly though obstacle environments with few informed individuals. The comparative simulation results are elaborated to show the feasibility, validity and superiority of our proposed algorithm. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Breeding and feeding ecology of pigeon guillemots (Cepphus columba) at Naked Island, Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report covers the breeding and feeding ecology of the pigeon guillemot at Naked Island, Alaska, as well as surveys of the Naked Island complex. Methods...

  1. Mycoplasma columbinum Isolated From a Racing Pigeon ( Columba livia ) With Arthritis.

    Science.gov (United States)

    Hellebuyck, Tom; Garmyn, An; De Cooman, Lien; Boyen, Filip; Pasmans, Frank; Martel, An

    2014-09-01

    A juvenile racing pigeon ( Columba livia ) was presented with drooping of the wing and inability to fly. On physical examination, the right shoulder joint was swollen. The pigeon was euthanatized and submitted for necropsy. An excessive amount of fibrin was present in the canalis triosseus with severe arthritis of the affected shoulder joint. A pure growth of Mycoplasma-like colonies was obtained on microbiological culture of the shoulder joint. A 16S ribosomal RNA gene-specific polymerase chain reaction assay was performed on the isolate and revealed 100% similarity with Mycoplasma columbinum . Although infectious arthritis in homing pigeons is primarily associated with paratyphoid and Streptococcus gallolyticus infection, clinical practitioners should consider the potential role of Mycoplasma columbinum in arthritis in pigeons.

  2. The complete mitochondrial genome of the Jacobin pigeon (Columba livia breed Jacobin).

    Science.gov (United States)

    He, Wen-Xiao; Jia, Jin-Feng

    2015-06-01

    The Jacobin is a breed of fancy pigeon developed over many years of selective breeding that originated in Asia. In the present work, we report the complete mitochondrial genome sequence of Jacobin pigeon for the first time. The total length of the mitogenome was 17,245 bp with the base composition of 30.18% for A, 23.98% for T, 31.88% for C, and 13.96% for G and an A-T (54.17 %)-rich feature was detected. It harbored 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and 1 non-coding control region. The arrangement of all genes was identical to the typical mitochondrial genomes of pigeon. The complete mitochondrial genome sequence of Jacobin pigeon would serve as an important data set of the germplasm resources for further study.

  3. CLINICO-PATHOLOGICAL OBSERVATIONS OF PIGEONS (COLUMBA LIVIA SUFFERING FROM NEWCASTLE DISEASE

    Directory of Open Access Journals (Sweden)

    S. Shaheen, A. D. Anjum and F. Rizvi

    2005-01-01

    Full Text Available A survey was conducted to study clinical signs, gross and histopathological lesions in pigeons with naturally occurring Newcastle disease. For this purpose, 30 pigeon lofts were visited. Among these, 14 lofts showed clinical signs of Newcastle disease, including mainly greenish white mucoid diarrhoea and nervous signs with high morbidity and mortality. Postmortem examination of affected birds showed lesions mainly in brain, liver, kidneys and spleen. Amongst various organs, kidneys were more frequently involved. Histopathological changes were also observed in lungs, liver, kidneys, brain and spleen. The results showed that the Newcastle disease virus was widespread in pigeons locally and caused heavy mortality. No preventive measures or vaccination is being adopted by pigeon fanciers to control the disease.

  4. Estimating the surface area of birds: using the homing pigeon (Columba livia) as a model.

    Science.gov (United States)

    Perez, Cristina R; Moye, John K; Pritsos, Chris A

    2014-05-08

    Estimation of the surface area of the avian body is valuable for thermoregulation and metabolism studies as well as for assessing exposure to oil and other surface-active organic pollutants from a spill. The use of frozen carcasses for surface area estimations prevents the ability to modify the posture of the bird. The surface area of six live homing pigeons in the fully extended flight position was estimated using a noninvasive method. An equation was derived to estimate the total surface area of a pigeon based on its body weight. A pigeon's surface area in the fully extended flight position is approximately 4 times larger than the surface area of a pigeon in the perching position. The surface area of a bird is dependent on its physical position, and, therefore, the fully extended flight position exhibits the maximum area of a bird and should be considered the true surface area of a bird.

  5. Mitochondrial genome sequence of Egyptian swift Rock Pigeon (Columba livia breed Egyptian swift).

    Science.gov (United States)

    Li, Chun-Hong; Shi, Wei; Shi, Wan-Yu

    2015-06-01

    The Egyptian swift Rock Pigeon is a breed of fancy pigeon developed over many years of selective breeding. In this work, we report the complete mitochondrial genome sequence of Egyptian swift Rock Pigeon. The total length of the mitogenome was 17,239 bp and its overall base composition was estimated to be 30.2% for A, 24.0% for T, 31.9% for C and 13.9% for G, indicating an A-T (54.2%)-rich feature in the mitogenome. It contained the typical structure of 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and a non-coding control region (D-loop region). The complete mitochondrial genome sequence of Egyptian swift Rock Pigeon would serve as an important data set of the germplasm resources for further study.

  6. Invasion of Flukes of the Echinostomatidae Family in Racing Pigeon ( Columba livia var. domestica) Lofts.

    Science.gov (United States)

    Ledwoń, Aleksandra; Dolka, Beata; Piasecki, Tomasz; Dolka, Izabella; Szeleszczuk, Piotr

    2016-06-01

    Over 4 years, only two known cases of fluke invasions were diagnosed in racing pigeons ( Columba livia ) originating from different regions of Poland. In both cases, the invasion was characterized by a very high mortality (approximately 70%), and the source of the infestation was snails of the Lymnaeidae family eaten by pigeons. Fluke invasions in pigeons are extremely rare and to date have not been described in Poland. Therefore, the occurrence of the symptoms of hemorrhagic diarrhea and sudden deaths of either adult pigeons or nestlings were suspected to be associated with poisoning. Autopsy revealed an invasion of flukes causing hemorrhagic enteritis. Renal failure and spleen atrophy were also found in the birds. Using molecular biology techniques, infestation with the fluke Echinostoma revolutum was determined in the second case.

  7. Helminth-bacteria interaction in the gut of domestic pigeon Columba livia domestica.

    Science.gov (United States)

    Biswal, Debraj; Nandi, Anadi Prasad; Chatterjee, Soumendranath

    2016-03-01

    The present paper is an attempt to study the interaction between the helminth parasite and bacteria residing in the gut of domestic pigeon, Columba livia domestica. Biochemical and molecular characterization of the gut bacterial isolate were done and the isolate was identified as Staphylococcus sp. DB1 (JX442510). The interaction of Staphylococcus sp. with Cotugnia cuneata, an intestinal helminth parasite of domestic pigeon was studied on the basis of the difference between 'mean worm burden' of antibiotic treated infected pigeons and infected pigeons without any antibiotic treatment. The ANOVA and Tukey tests of the data obtained showed that antibiotic treatment reduced the mean worm burden significantly. The biochemical properties of Staphylococcus sp. DB1 (JX442510) also showed a mutualistic relationship with the physiology of C. cuneata.

  8. Waiting time before release increases the motivation to home in homing pigeons (Columba livia)

    National Research Council Canada - National Science Library

    Dell'Ariccia, Gaia; Costantini, David; Dell'Omo, Giacomo; Lipp, Hans-Peter

    2009-01-01

    .... Quite often, the last pigeons disappear straightforward from the release site. The question is whether this reflects improved orientation because of prolonged exposure to the release place or whether it reflects increased homing motivation...

  9. The role of contingencies and “principles of behavioral variation” in pigeons' pecking

    OpenAIRE

    Fenner, Douglas

    1980-01-01

    Staddon and Simmelhag's proposal that behavior is produced by “principles of behavioral variation” instead of contingencies of reinforcement was tested in two experiments. In the first experiment pigeons were exposed to either a fixed-interval schedule of response-contingent reinforcement, an autoshaping schedule of stimulus-contingent reinforcement, or a fixed-time schedule of noncontingent reinforcement. Pigeons exposed to contingent reinforcement came to peck more rapidly than those expose...

  10. Intra-annual patterns in adult band-tailed pigeon survival estimates

    Science.gov (United States)

    Casazza, Michael L.; Coates, Peter S.; Overton, Cory T.; Howe, Kristy H.

    2015-01-01

    Context: The band-tailed pigeon (Patagioenas fasciata) is a migratory species occurring in western North America with low recruitment potential and populations that have declined an average of 2.4% per year since the 1960s. Investigations into band-tailed pigeon demographic rates date back to the early 1900s, and existing annual survival rate estimates were derived in the 1970s using band return data.

  11. Pigeons with ablated pyriform cortex home from familiar but not from unfamiliar sites.

    OpenAIRE

    Papi, F; Casini, G.

    1990-01-01

    Homing behavior was tested in pigeons (Columba livia) after removing a portion of the ventrolateral telencephalon, which receives extensive projections from the olfactory bulb and is comparable with the mammalian pyriform cortex. Ablated pigeons show unaffected cardiac responses to odorous stimuli but altered homing behavior. After the operation, the birds were trained by repeated flock releases along with control birds from a site 40 km from the loft. After being released singly from this fa...

  12. Effect of a single free food presentation on extinction responding in a multiple schedule.

    Science.gov (United States)

    Reiss, Adam J; Bell, Matthew C

    2016-09-01

    The present study was designed to assess the effect of a single, response-independent food presentation on responding during extinction. Using a two-component multiple schedule, we examined differences in pigeons' extinction responding resulting from a single response-independent food presentation occurring at the beginning of the experimental session (30-s prior to the beginning of the first component). One component presented reinforcement according to a variable interval 45-s schedule and the second presented reinforcement according to a variable interval 180-s schedule. After establishing stable baseline responding we extinguished responding. We systematically manipulated the presence or absence of a single 3-s free food presentation using the food hopper that occurred 30-s prior to the presentation of the first component. We found the single free food presentation increased persistence of responding in extinction. This finding is inconsistent with behavioral momentum theory inasmuch as it assigns a response disruptive role to food presentations occurring outside of the context of the target operant.

  13. [Air transport biomechanical risk: reduced mobility passengers' handling].

    Science.gov (United States)

    Draicchio, F; Campoli, G; Silvetti, A; Badellino, E; Forzano, F; Ranavolo, A; Iavicoli, S; Campagna, G; Raffaele, G; Gismondi, M

    2012-01-01

    As the airport traffic increases there is a continuous increase of passengers with different motor disabilities. Disabled passenger's assistance causes a biomechanical overload in airport workers. Some disabled passengers are classified by IATA as WCHC (wheel chair in cabin or Charlie). Our study, was performed in one of the most important Italian airport on Charlie passengers (about 10% of all assistances). We identified four critical points: 1) wheelchair and baggage moving (unstable load), 2) inclined ramps with worker's backwards steps and braked wheelchair to prevent passenger tipping or falling, 3) transfer from standard wheelchair to bicycle wheelchair, specifically designed for the aisle; 4.) transfer from bicycle wheelchair to aircraft seat. The last two points required sometimes to lift passengers over the armrest and positioning them on a window side seat, causing a serious increase of biomechanical load. For each critical point we have proposed technical and organizational measures to reduce airport worker's biomechanical risk.

  14. Global Positioning System-Based Stimulation for Robo-Pigeons in Open Space

    Directory of Open Access Journals (Sweden)

    Junqing Yang

    2017-08-01

    Full Text Available An evaluation method is described that will enable researchers to study fight control characteristics of robo-pigeons in fully open space. It is not limited by the experimental environment and overcomes environmental interference with flight control in small experimental spaces using a compact system. The system consists of two components: a global positioning system (GPS-based stimulator with dimensions of 38 mm × 26 mm × 8 mm and a weight of 18 g that can easily be carried by a pigeon as a backpack and a PC-based program developed in Virtual C++. The GPS-based stimulator generates variable stimulation and automatically records the GPS data and stimulus parameters. The PC-based program analyzes the recorded data and displays the flight trajectory of the tested robo-pigeon on a digital map. This method enables quick and clear evaluation of the flight control characteristics of a robo-pigeon in open space based on its visual trajectory, as well as further optimization of the microelectric stimulation parameters to improve the design of robo-pigeons. The functional effectiveness of the method was investigated and verified by performing flight control experiments using a robo-pigeon in open space.

  15. Flight performance energetics and water turnovers of Tippler Pigeons with a harness and doorsal load

    Science.gov (United States)

    Gessaman, James A.; Workman, Gar W.; Fuller, Mark R.

    1991-01-01

    We measured carbon dioxide production and water efflux of 12 tippler pigeons (Columba spp.) during seven experimental flights using the doubly labeled water (DLW) method. Prior to the experiment birds were randomly assigned to one of two groups. One group flew as controls (no load or harness) on all seven flights. The other group wore a harness on two flights, a dorsal load/harness package (weighing about 5% of a birda??s mass) on two flights, and they were without a load in three flights. Plight duration of pigeons with only a harness and with a dorsal load/harness package was 21 and 26% less, respectively, than the controls. Pigeons wearing a harness, or wearing a dorsal load/harness package lost water 50-90%, and 57-100% faster, respectively, than control pigeons. The mean CO, production of pigeons wearing a harness or a load/harness package was not significantly different than pigeons without a harness or load. The small sample sizes and large variability in DLW measurements precluded a good test of the energetic cost of flying with a harness and dorsal load.

  16. Flight performance, energetics and water turnover of tippler pigeons with a harness and dorsal load

    Science.gov (United States)

    Gessaman, J.A.; Workman, G.W.; Fuller, M.R.

    1991-01-01

    We measured carbon dioxide production and water efflux of 12 tippler pigeons (Columba spp.) during seven experimental flights using the doubly labeled water (DLW) method. Prior to the experiment birds were randomly assigned to one of two groups. One group flew as controls (no load or harness) on all seven flights. The other group wore a harness on two flights, a dorsal load/harness package (weighing about 5% of a bird's mass) on two flights, and they were without a load in three flights. Flight duration of pigeons with only a harness and with a dorsal load/harness package was 21 and 26% less, respectively, than the controls. Pigeons wearing a harness, or wearing a dorsal load/harness package lost water 50-90%, and 57-100% faster, respectively, than control pigeons. The mean CO2 production of pigeons wearing a harness or a load/harness package was not significantly different than pigeons without a harness or load. The small sample sizes and large variability in DLW measuremets precluded a good test of the energetic cost of flying with a harness and dorsal load.

  17. Tracking pigeons in a magnetic anomaly and in magnetically "quiet" terrain

    Science.gov (United States)

    Schiffner, Ingo; Fuhrmann, Patrick; Wiltschko, Roswitha

    2011-07-01

    Pigeons were released at two sites of equal distance from the loft, one within a magnetic anomaly, the other in magnetically quiet terrain, and their tracks were recorded with the help of GPS receivers. A comparison of the beginning of the tracks revealed striking differences: within the anomaly, the initial phase lasted longer, and the distance flown was longer, with the pigeons' headings considerably farther from the home direction. During the following departure phase, the birds were well homeward oriented at the magnetically quiet site, whereas they continued to be disoriented within the anomaly. Comparing the tracks in the anomaly with the underlying magnetic contours shows considerable differences between individuals, without a common pattern emerging. The differences in magnetic intensity along the pigeons' path do not differ from a random distribution of intensity differences around the release site, indicating that the magnetic contours do not directly affect the pigeons' routes. Within the anomaly, pigeons take longer until their flights are oriented, but 5 km from the release point, the birds, still within the anomaly, are also significantly oriented in the home direction. These findings support the assumption that magnetically anomalous conditions initially interfere with the pigeons' navigational processes, with birds showing rather individual responses in their attempts to overcome these problems.

  18. Cue salience influences the use of height cues in reorientation in pigeons (Columba livia).

    Science.gov (United States)

    Du, Yu; Mahdi, Nuha; Paul, Breanne; Spetch, Marcia L

    2016-07-01

    Although orienting ability has been examined with numerous types of cues, most research has focused only on cues from the horizontal plane. The current study investigated pigeons' use of wall height, a vertical cue, in an open-field task and compared it with their use of horizontal cues. Pigeons were trained to locate food in 2 diagonal corners of a rectangular enclosure with 2 opposite high walls as height cues. Before each trial, pigeons were rotated to disorient them. In training, pigeons could use either the horizontal cues from the rectangular enclosure or the height information from the walls to locate the food. In testing, the apparatus was modified to provide (a) horizontal cues only, (b) height cues only, and (c) both height and horizontal cues in conflict. In Experiment 1 the lower and high walls, respectively, were 40 and 80 cm, whereas in Experiment 2 they were made more perceptually salient by shortening them to 20 and 40 cm. Pigeons accurately located the goal corners with horizontal cues alone in both experiments, but they searched accurately with height cues alone only in Experiment 2. When the height cues conflicted with horizontal cues, pigeons preferred the horizontal cues over the height cues in Experiment 1 but not in Experiment 2, suggesting that perceptual salience influences the relative weighting of cues. (PsycINFO Database Record

  19. Age-related spatial working memory deficits in homing pigeons (Columba livia).

    Science.gov (United States)

    Coppola, Vincent J; Hough, Gerald; Bingman, Verner P

    2014-12-01

    The hippocampus is particularly susceptible to age-related degeneration that, like hippocampal lesions, is thought to lead to age-related decline in spatial memory and navigation. Lesions to the avian hippocampal formation (HF) also result in impaired spatial memory and navigation, but the relationship between aging and HF-dependent spatial cognition is unknown. To investigate possible age-related decline in avian spatial cognition, the current study investigated spatial working memory performance in older homing pigeons (10+ years of age). Pigeons completed a behavioral procedure nearly identical to the delayed spatial, win-shift procedure in a modified radial arm maze that has been previously used to study spatial working memory in rats and pigeons. The results revealed that the older pigeons required a greater number of choices to task completion and were less accurate with their first 4 choices as compared to younger pigeons (1-2 years of age). In addition, older pigeons were more likely to adopt a stereotyped sampling strategy, which explained in part their impaired performance. To the best of our knowledge, this study is the first to demonstrate an age-related impairment of HF-dependent, spatial memory in birds. Implications and future directions of the findings are discussed.

  20. Functional Similarities between Pigeon ‘Milk’ and Mammalian Milk: Induction of Immune Gene Expression and Modification of the Microbiota

    OpenAIRE

    Gillespie, Meagan J; Dragana Stanley; Honglei Chen; Donald, John A.; Nicholas, Kevin R.; Robert J Moore; Crowley, Tamsyn M

    2012-01-01

    Pigeon 'milk' and mammalian milk have functional similarities in terms of nutritional benefit and delivery of immunoglobulins to the young. Mammalian milk has been clearly shown to aid in the development of the immune system and microbiota of the young, but similar effects have not yet been attributed to pigeon 'milk'. Therefore, using a chicken model, we investigated the effect of pigeon 'milk' on immune gene expression in the Gut Associated Lymphoid Tissue (GALT) and on the composition of t...

  1. The Simultaneous Vehicle Scheduling and Passenger Service Problem

    DEFF Research Database (Denmark)

    Petersen, Hanne Løhmann; Larsen, Allan; Madsen, Oli B.G.

    Passengers using public transport systems often experience waiting times when transferring between two scheduled services. We propose a planning approach which seeks to obtain a favorable trade-off between the conflicting objectives passenger service and operating cost, by allowing some moderate...... by the express-bus network in the Greater Copenhagen Area. The results are encouraging and indicate a potential decrease of passenger waiting times in the network of 10-20%, with the vehicle scheduling costs remaining largely unaffected....

  2. August Passenger and Cargo Numbers Set New Highs

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ Passenger and cargo numbers set new highs in August, the second consecutive month that both areas of operation at Dragonair posted record figures. The airline flew 444,498 passengers in August to record its third consecutive monthly record. The number was 7.7%higher than in July, with travel in both months driven by holiday traffic. August 15 saw a new daily mark set, with 17,220passengers carried on the day.

  3. The Sixth Great Mass Extinction

    Science.gov (United States)

    Wagler, Ron

    2012-01-01

    Five past great mass extinctions have occurred during Earth's history. Humanity is currently in the midst of a sixth, human-induced great mass extinction of plant and animal life (e.g., Alroy 2008; Jackson 2008; Lewis 2006; McDaniel and Borton 2002; Rockstrom et al. 2009; Rohr et al. 2008; Steffen, Crutzen, and McNeill 2007; Thomas et al. 2004;…

  4. Refractive sectors in the visual field of the pigeon eye.

    Science.gov (United States)

    Fitzke, F W; Hayes, B P; Hodos, W; Holden, A L; Low, J C

    1985-12-01

    Scheiner's principle has been used in electroretinographic optometry to refract the photoreceptor plane in different regions of the visual field of the pigeon eye. Along the horizon and in the upper visual field the eye is emmetropic, or nearly so. Below the horizon the eye becomes progressively more myopic at more negative elevations, refractive state falling to -5D at -90 deg. Lower field myopia is not an artifact of oblique astigmatism, nor of an aberration symmetrical about the optical axis. It is suggested that lower field myopia is a biological adaptation suited to keep the photoreceptors in the upper retina conjugate with the ground. Refractive state below the horizon can be fitted with a sine function by varying a parameter H (eye-ground height). The value of H agrees well with directly measured eye-ground height.

  5. Iridescence in the neck feathers of domestic pigeons

    Science.gov (United States)

    Yin, Haiwei; Shi, Lei; Sha, Jing; Li, Yizhou; Qin, Youhua; Dong, Biqin; Meyer, Serge; Liu, Xiaohan; Zhao, Li; Zi, Jian

    2006-11-01

    We conducted structural characterizations, reflection measurements, and theoretical simulations on the iridescent green and purple neck feathers of domestic pigeons (Columba livia domestica). We found that both green and purple barbules are composed of an outer keratin cortex layer surrounding a medullary layer. The thickness of the keratin cortex layer shows a distinct difference between green and purple barbules. Green barbules vary colors from green to purple with the observing angle changed from normal to oblique, while purple barbules from purple to green in an opposite way. Both the experimental and theoretical results suggest that structural colors in green and purple neck feathers should originate from the interference in the top keratin cortex layer, while the structure beyond acts as a poor mirror.

  6. Incidence of gastrointestinal parasitism of captive wild pigeons at Nagpur

    Directory of Open Access Journals (Sweden)

    A. T. Borghare

    Full Text Available Present study was planned to investigate the helminthic infection in captive wild pigeons (Columba livia at Maharajbagh Zoo Nagpur. All the 30 samples examined were found positive either with single or mixed helminthic infections. The result showed that the incidence of Capillaria sp, Ascaridia sp and  Hetarakis sp. were 56.66%, 76.66%, 16.66% respectively. Mixed parasitic infection was recorded in around 17 samples with either Ascaridia sp. and Capillaria sp or with Ascaridia sp. and Heterakis sp. One of 30 samples examined were found with the cysts of Balantidium coli. [Vet World 2009; 2(9.000: 343-

  7. Extinction, relapse, and behavioral momentum.

    Science.gov (United States)

    Podlesnik, Christopher A; Shahan, Timothy A

    2010-05-01

    Previous experiments on behavioral momentum have shown that relative resistance to extinction of operant behavior in the presence of a discriminative stimulus depends upon the baseline rate or magnitude of reinforcement associated with that stimulus (i.e., the Pavlovian stimulus-reinforcer relation). Recently, we have shown that relapse of operant behavior in reinstatement, resurgence, and context renewal preparations also is a function of baseline stimulus-reinforcer relations. In this paper we present new data examining the role of baseline stimulus-reinforcer relations on resistance to extinction and relapse using a variety of baseline training conditions and relapse operations. Furthermore, we evaluate the adequacy of a behavioral momentum based model in accounting for the results. The model suggests that relapse occurs as a result of a decrease in the disruptive impact of extinction precipitated by a change in circumstances associated with extinction, and that the degree of relapse is a function of the pre-extinction baseline Pavlovian stimulus-reinforcer relation. Across experiments, relative resistance to extinction and relapse were greater in the presence of stimuli associated with more favorable conditions of reinforcement and were positively related to one another. In addition, the model did a good job in accounting for these effects. Thus, behavioral momentum theory may provide a useful quantitative approach for characterizing how differential reinforcement conditions contribute to relapse of operant behavior.

  8. The pigeon (Columba livia) model of spontaneous atherosclerosis.

    Science.gov (United States)

    Anderson, J L; Smith, S C; Taylor, R L

    2014-11-01

    Multiple animal models have been employed to study human atherosclerosis, the principal cause of mortality in the United States. Each model has individual advantages related to specific pathologies. Initiation, the earliest disease phase, is best modeled by the White Carneau (WC-As) pigeon. Atherosclerosis develops spontaneously in the WC-As without either external manipulation or known risk factors. Furthermore, susceptibility is caused by a single gene defect inherited in an autosomal recessive manner. The Show Racer (SR-Ar) pigeon is resistant to atherosclerosis. Breed differences in the biochemistry and metabolism of celiac foci cells have been described. For example, WC-As have lower oxidative metabolism but higher amounts of chondroitin-6-sulfate and nonesterified fatty acids compared with SR-Ar. Gene expression in aortic smooth muscle cells was compared between breeds using representational difference analysis and microarray analysis. Energy metabolism and cellular phenotype were the chief gene expression differences. Glycolysis and synthetic cell types were related to the WC-As but oxidative metabolism and contractile cell types were related to the SR-Ar. Rosiglitazone, a PPARγ agonist, blocked RNA binding motif (RBMS1) expression in WC-As cells. The drug may act through the c-myc oncogene as RBMS1 is a c-myc target. Proteomic tests of aortic smooth muscle cells supported greater glycosylation in the WC-As and a transforming growth factor β effect in SR-Ar. Unoxidized fatty acids build up in WC-As cells because of their metabolic deficiency, ultimately preventing the contractile phenotype in these cells. The single gene responsible for the disease is likely regulatory in nature.

  9. Implementing Composite Superstructures in Large Passenger Ships

    DEFF Research Database (Denmark)

    Karatzas, Vasileios; Berggreen, Christian; Jensen, Jørgen Juncher;

    2015-01-01

    This study focuses on the structural response of the part of the superstructure of a RoPax ferry that has been redesigned using composite materials. The composite superstructure is presented and subsequently compared to the existing steel design considering different loading conditions by the use...... of FE modelling.Results indicate that it is not the structural response of the superstructure that inhibits the implementation of composites in the superstructures of large passenger ships but the complicated design procedure and the acceptance of such solutions by the regulatory bodies....

  10. Telemedical Advice to Long Distance Passenger Ferries

    DEFF Research Database (Denmark)

    Jensen, Olaf Chresten; Bøggild, Niels Bo; Kristensen, Søren

    with morphine. The NSAID drugs were supplied from the other passengers. Among the patients with visceral pain 1 was treated with NSAID and 22 with opioids. Of the 23 patients treated with opioids, 19 had sublingual Buprenorphine, 3 morphine injections and 1 used his personal codeine tablets. No problems were...... reported from resorption of the Buprenorphine resoriblets, which therefore seemed to work well. At least 77 patients would have benefited from use of non-steroid anti-inflammatory drugs. Conclusions: The paramedical assistance and the medicine chest content were considered insufficient in The paramedical...

  11. Thermal Transgressions and Phanerozoic Extinctions

    Science.gov (United States)

    Worsley, T. R.; Kidder, D. L.

    2007-12-01

    A number of significant Phanerozoic extinctions are associated with marine transgressions that were probably driven by rapid ocean warming. The conditions associated with what we call thermal transgressions are extremely stressful to life on Earth. The Earth system setting associated with end-Permian extinction exemplifies an end-member case of our model. The conditions favoring extreme warmth and sea-level increases driven by thermal expansion are also conducive to changes in ocean circulation that foster widespread anoxia and sulfidic subsurface ocean waters. Equable climates are characterized by reduced wind shear and weak surface ocean circulation. Late Permian and Early Triassic thermohaline circulation differs considerably from today's world, with minimal polar sinking and intensified mid-latitude sinking that delivers sulfate from shallow evaporative areas to deeper water where it is reduced to sulfide. Reduced nutrient input to oceans from land at many of the extinction intervals results from diminished silicate weathering and weakened delivery of iron via eolian dust. The falloff in iron-bearing dust leads to minimal nitrate production, weakening food webs and rendering faunas and floras more susceptible to extinction when stressed. Factors such as heat, anoxia, ocean acidification, hypercapnia, and hydrogen sulfide poisoning would significantly affect these biotas. Intervals of tectonic quiescence set up preconditions favoring extinctions. Reductions in chemical silicate weathering lead to carbon dioxide buildup, oxygen drawdown, nutrient depletion, wind and ocean current abatement, long-term global warming, and ocean acidification. The effects of extinction triggers such as large igneous provinces, bolide impacts, and episodes of sudden methane release are more potent against the backdrop of our proposed preconditions. Extinctions that have characteristics we call for in the thermal transgressions include the Early Cambrian Sinsk event, as well as

  12. Non-seatbelt use and associated factors among passengers.

    Science.gov (United States)

    Han, Guang-Ming

    2017-06-01

    Seatbelt use is the most effective way to save lives and reduce severe injuries. However, the percentage of non-seatbelt use is still high among drivers and passengers. Although the factors related to non-seatbelt use among drivers have been widely studied, the factors associated with non-seatbelt use among passengers have not been well documented. In addition, recent surveys showed that the driver's attitude has a significant impact on the passenger's seatbelt use. However, the lower response rate and less accurate of self-reported seatbelt use in survey studies, especially among participants who had a high level perception of penalty for non-seatbelt use. Therefore, we examined the association between passenger's seatbelt use and driver's seatbelt use with a statewide injury surveillance system. 36,012 passengers who were involved in motor vehicle crashes (MVC) in 2004-2013 were included in this study. Our results showed that if a driver wore a seatbelt, 92.6% of his/her passengers also wore seatbelts while if a driver did not wear a seatbelt, only 19.1% of his/her passengers wore seatbelts. Compared to the passenger whose driver wore a seatbelt, the passenger had a significantly higher probability of non-seatbelt use (odds ratio = 46.7; 95% confidence intervals, 42.7-51.1) if his/her driver did not wear a seatbelt. The driver has the greatest influence on the passenger's seatbelt use. The findings will provide important information for future public health practices to increase seatbelt use at the highest possible rate for passengers, such as educational interventions for drivers and seatbelt reminders use.

  13. 75 FR 7599 - Notice of Public Hearing; Passenger Vessel Financial Responsibility

    Science.gov (United States)

    2010-02-22

    ... Notice of Public Hearing; Passenger Vessel Financial Responsibility AGENCY: Federal Maritime Commission... Passenger Vessel Financial Responsibility Program. DATES: The due date for submitting a request to... make presentations concerning the Commission's passenger vessel financial responsibility program. The...

  14. Cardiorespiratory parameters in the awake pigeon and during anaesthesia with isoflurane.

    Science.gov (United States)

    Botman, Julie; Dugdale, Alex; Gabriel, Fabien; Vandeweerd, Jean-Michel

    2016-01-01

    To determine baseline cardiovascular and respiratory variables in the awake pigeon, and to assess those variables during anaesthesia at the individual minimal anaesthetic concentration (MAC) of isoflurane during spontaneous breathing. Prospective, experimental trial. Seven healthy adult pigeons weighing a mean ± standard deviation (SD) of 438 ± 38 g. Heart rate (HR), heart rhythm, respiratory rate (fR), end-expired carbon dioxide tension (Pe'CO2), indirect systolic arterial pressure (SAP) and cloacal temperature (T) were measured in birds in the awake state (after acclimatization to handling). Two weeks later, the pigeons were anaesthetized with isoflurane in order to determine their MAC and evaluate the same cardiovascular and respiratory variables during a further 40 minutes of isoflurane anaesthesia. In the awake pigeon, mean ± SD HR, SAP, fR, Pe'CO2 and T were, respectively, 155 ± 28 beats minute(-1), 155 ± 21 mmHg, 34 ± 6 breaths minute(-1), 38 ± 8 mmHg (5.1 ± 1.1 kPa) and 41.8 ± 0.5 °C. Mean isoflurane MAC was 1.8 ± 0.4%. During maintenance of anaesthesia at MAC, although no significant decreases between values obtained in the awake and anaesthetized states emerged in HR or respiratory rate, significant decreases in SAP and cloacal temperature and an increase in Pe'CO2 were observed. No arrhythmia was identified in awake pigeons, whereas second- and third-degree atrioventricular blocks occurred under isoflurane. Isoflurane MAC in pigeons appeared to be higher than in other avian species. Isoflurane anaesthesia in pigeons resulted in hypercapnia, hypotension, mild hypothermia and second- and third-degree atrioventricular blocks. © 2015 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

  15. Scale-dependent associations of Band-tailed Pigeon counts at mineral sites

    Science.gov (United States)

    Overton, Cory T.; Casazza, Michael L.; Coates, Peter S.

    2010-01-01

    The abundance of Band-tailed Pigeons (Patagioenas fasciata monilis) has declined substantially from historic numbers along the Pacific Coast. Identification of patterns and causative factors of this decline are hampered because habitat use data are limited, and temporal and spatial variability patterns associated with population indices are not known. Furthermore, counts are influenced not only by pigeon abundance but also by rate of visitation to mineral sites, which may not be consistent. To address these issues, we conducted mineral site counts during 2001 and 2002 at 20 locations from 4 regions in the Pacific Northwest, including central Oregon and western Washington, USA, and British Columbia, Canada. We developed inference models that consisted of environmental factors and spatial characteristics at multiple spatial scales. Based on information theory, we compared models within a final set that included variables measured at 3 spatial scales (0.03 ha, 3.14 ha, and 7850 ha). Pigeon counts increased from central Oregon through northern Oregon and decreased into British Columbia. After accounting for this spatial pattern, we found that pigeon counts increased 12% ± 2.7 with a 10% increase in the amount of deciduous forested area within 100 m from a mineral site. Also, distance from the mineral site of interest to the nearest known mineral site was positively related to pigeon counts. These findings provide direction for future research focusing on understanding the relationships between indices of relative abundance and complete counts (censuses) of pigeon populations by identifying habitat characteristics that might influence visitation rates. Furthermore, our results suggest that spatial arrangement of mineral sites influences Band-tailed Pigeon counts and the populations which those counts represent.

  16. Comparative cophylogenetics of Australian phabine pigeons and doves (Aves: Columbidae) and their feather lice (Insecta: Phthiraptera)

    Science.gov (United States)

    Sweet, Andrew D.; Chesser, R. Terry; Johnson, Kevin P.

    2017-01-01

    Host–parasite coevolutionary histories can differ among multiple groups of parasites associated with the same group of hosts. For example, parasitic wing and body lice (Insecta: Phthiraptera) of New World pigeons and doves (Aves: Columbidae) differ in their cophylogenetic patterns, with body lice exhibiting higher phylogenetic congruence with their hosts than wing lice. In this study, we focus on the wing and body lice of Australian phabine pigeons and doves to determine whether the patterns in New World pigeons and doves are consistent with those of pigeons and doves from other regions. Using molecular sequence data for most phabine species and their lice, we estimated phylogenetic trees for all three groups (pigeons and doves, wing lice and body lice), and compared the phabine (host) tree with both parasite trees using multiple cophylogenetic methods. We found a pattern opposite to that found for New World pigeons and doves, with Australian wing lice showing congruence with their hosts, and body lice exhibiting a lack of congruence. There are no documented records of hippoboscid flies associated with Australian phabines, thus these lice may lack the opportunity to disperse among host species by attaching to hippoboscid flies (phoresis), which could explain these patterns. However, additional sampling for flies is needed to confirm this hypothesis. Large differences in body size among phabine pigeons and doves may also help to explain the congruence of the wing lice with their hosts. It may be more difficult for wing lice than body lice to switch among hosts that vary more dramatically in size. The results from this study highlight how host–parasite coevolutionary histories can vary by region, and how local factors can shape the relationship.

  17. [Effects of the environment on health of feral pigeons (Columba livia)].

    Science.gov (United States)

    Schreiber, Tim; Kamphausen, Ludger; Haag-Wackernagel, Daniel

    2015-01-01

    We examined 80 feral pigeons and their fecal samples from two feral pigeon lofts of the "Pigeon Action of Basel" (Switzerland) for different pathogens. The tested material harbored four pathogenic agents transmissible to humans (Chlamydia spp., Salmonella spec., Campylobacter jejuni, Cryptococcus neoformans) In addition several pathogens were found which are no zoonotic agents but potentially pathogenic for the pigeons themselves, such as Trichomonas gallinae, coccidia, helminths, ectoparasites and fungi. The number of pathogens and parasites detected in the fecal samples varied significantly between the two localities. The pigeons of the two investigated breeding flocks differed in nutritional status and the incidence of two species of feather lice, Columbicola columbae and Campanulotes bidentatus compar. The prevalence of Trichomonas gallinae between juveniles and adults was not significantly different but juveniles exhibited significantly heavier infestation if infected. Individuals with a good nutritional status tend to show heavier infestation with Trichomonas gallinae compared to birds with moderate or poor nutritional status. Birds with a poor nutritional status tend to suffer from a heavier infestation with the feather louse C. columbae, and birds with a good nutritional status show significant heavier infestation with C. bidentatus compar. It was remarkable that one of the two investigated breeding populations almost gave up its breeding activity for two years because of the loss of its familiar food source. Nevertheless, this population showed a better nutritional status than the population without restrictions in the acquisition of food. This fact could be interpreted by the existence of a biological control mechanism for suppression of the reproduction in degraded environmental conditions to ensure the survival of the adults. If this assumption is correct, the feeding of feral pigeons by animal lovers possibly causes impairment of pigeon's health in

  18. Defensive behaviors and prosencephalic neurogenesis in pigeons (Columba livia) are affected by environmental enrichment in adulthood.

    Science.gov (United States)

    Melleu, F F; Pinheiro, M V; Lino-de-Oliveira, C; Marino-Neto, J

    2016-05-01

    Neurogenesis in the adult brain appears to be phylogenetically conserved across the animal kingdom. In pigeons and other adult non-oscine birds, immature neurons are observed in several prosencephalic areas, suggesting that neurogenesis may participate in the control of different behaviors. The mechanisms controlling neurogenesis and its relevance to defensive behaviors in non-oscine birds remain elusive. Herein, the contribution of the environment to behavior and neurogenesis of pigeons was investigated. Adult pigeons (Columba livia, n = 6/group), housed in standard (SE) or enriched environment (EE) for 42 days, were exposed to an unfamiliar environment (UE) followed by presentation to a novel object (NO). Video recordings of UE+NO tests were analyzed and scored for latency, duration and frequency of angular head movements, peeping, grooming, immobility and locomotion. Twenty-four hours later, pigeons were submitted to the tonic immobility test (TI) and number of trials for TI and TI duration were scored, followed by euthanasia 2 h later. Brains were immunohistochemically processed to reveal doublecortin (DCX), a marker for newborn neurons. Compared to those housed in SE, the pigeons housed in EE responded to a NO with more immobility. In addition, the pigeons housed in EE presented longer TI, more DCX-immunoreactive (DCX-ir) cells in the hippocampus and fewer DCX-ir cells in the lateral striatum than those housed in SE. There was no correlation between the number of DCX-ir cells and the scores of immobility in behavioral tests. Together, these data suggest that enrichment favored behavioral inhibition and neurogenesis in the adult pigeons through different, parallel mechanisms.

  19. Video surveillance of passengers with mug shots

    Science.gov (United States)

    Hsu, Ming Kai; Lee, Ting N.; Szu, Harold

    2010-04-01

    The authority officer relies on facial mug-shots to spot suspects among crowds. Passing through a check point, the facial displays and printouts operate in low resolution fixed poses. Thus, a databases-cuing video is recommended for real-time surveillance with Aided-Target Recognition (AiTR) prompting the inspector taking a closer second look at a specific passenger. Taking advantage of commercial available Face Detection System on Chips (SOC) at 0.04sec, we develop a fast and smart algorithm to sort facial poses among passengers. We can increase the overlapping POFs (pixels on faces) in matching mug shots at arbitrary poses with sorted facial poses. Lemma: We define the long exposure as time average of facial poses and the short exposure as single facial pose in a frame of video in 30 Hz. The fiduciary triangle is defined among two eyes and nose-top. Theorem Self-Reference Matched Filtering (Szu et al. Opt Comm. 1980; JOSA, 1982) to Facial-Pose: If we replace the desirable output of Weiner filter as the long exposure, then the filter can select a short exposure as the normal view. Corollary: Given a short exposure as normal view, the fiduciary triangle can decide all poses from left-to-right and top-to-down.

  20. Cardiovascular emergencies in cruise ship passengers.

    Science.gov (United States)

    Novaro, Gian M; Bush, Howard S; Fromkin, Kenneth R; Shen, Michael Y; Helguera, Marcelo; Pinski, Sergio L; Asher, Craig R

    2010-01-15

    More than 10 million people, many elderly and likely to harbor cardiovascular (CV) disease, embark on cruise ship travel worldwide every year. The clinical presentation and outcome of CV emergencies presenting during cruise ship travel remain largely unknown. Our department provides contracted cardiology consultations to several large cruise lines. We prospectively maintained a registry of all such consultations during a 2-year period. One hundred consecutive patients were identified (age 66 +/- 14 years, range 18 to 90, 76% men). The most common symptom was chest pain (50%). The most common diagnosis was acute coronary syndrome (58%; ST elevation in 21% and non-ST elevation in 37%). On-board mortality was 3%. Overall, 73% of patients required hospital triage. Of the 25 patients triaged to our institution, 17 underwent a revascularization procedure. One patient died. Ten percent of patients had cardiac symptoms in the days or weeks before boarding; all required hospital triage. Access to a baseline electrocardiogram would have been clinically useful in 23% of cases. In conclusion, CV emergencies, such as acute coronary syndrome and heart failure, are not uncommon on cruise ships. They are often serious, requiring hospital triage and coronary revascularization. A pretravel medical evaluation is recommended for passengers with a cardiac history or a high-risk profile. Passengers should be encouraged to bring a copy of their electrocardiogram on board if abnormal. Cruise lines should establish mechanisms for prompt consultation and triage.

  1. Route planning for airport personnel transporting passengers with reduced mobility

    DEFF Research Database (Denmark)

    Reinhardt, Line Blander; Clausen, Tommy; Pisinger, David

    Major airports have an average throughput of more than 100,000 passengers per day, some of which will need special assistance. The largest airports have a daily average throughput of more than 500 passengers with reduced mobility. A significant number of people and busses are assigned to provide ...

  2. Energy scenarios for European passenger transport in the year 2030

    NARCIS (Netherlands)

    Rienstra, S.A.; Smokers, R.T.M.; Nijkamp, P.

    2000-01-01

    In this paper four energy scenarios for Westy-European passenger transport are developed. To start with, the present transport system as a base-line case is described and analysed. Next, for each scenario we sketch how the passenger transport system may look like in terms of the use of various

  3. Child Passenger Safety (A Cup of Health with CDC)

    Centers for Disease Control (CDC) Podcasts

    2016-09-29

    Proper installation and use of car seats and booster seats for child passengers can save their lives. CDC recommends drivers ensure children are always buckled up. In this podcast, Bethany West discusses how to keep young passengers as safe as possible.  Created: 9/29/2016 by MMWR.   Date Released: 9/29/2016.

  4. CONCEPTUAL APPROACHES TO CREATE CONTROL MECHANISM BY PASSENGER COMMUTATION SERVICES

    Directory of Open Access Journals (Sweden)

    V. O. Zadoya

    2010-11-01

    Full Text Available In the article the basic approaches of improving a management mechanism for passenger suburban railway transportations are considered, and the classification of reformation models for passenger suburban railway transportations depending on scales, degree of independence, department subordination and amount of proprietors of future company is offered.

  5. Flexible connections in PESP models for cyclic passenger railway timetabling

    NARCIS (Netherlands)

    L.G. Kroon (Leo); L.W.P. Peeters (Leon); J.C. Wagenaar (Joris); R.A. Zuidwijk (Rob)

    2014-01-01

    textabstractIn this paper we describe how rolling stock and passenger connections in a cyclic railway timetable can be modeled in a flexible way within the model for the Periodic Event-Scheduling Problem (PESP). Usually, PESP models assume that the constraints for rolling stock or passenger connecti

  6. Energy scenarios for European passenger transport in the year 2030

    NARCIS (Netherlands)

    Rienstra, S.A.; Smokers, R.T.M.; Nijkamp, P.

    2000-01-01

    In this paper four energy scenarios for Westy-European passenger transport are developed. To start with, the present transport system as a base-line case is described and analysed. Next, for each scenario we sketch how the passenger transport system may look like in terms of the use of various exist

  7. The extinction of the dinosaurs.

    Science.gov (United States)

    Brusatte, Stephen L; Butler, Richard J; Barrett, Paul M; Carrano, Matthew T; Evans, David C; Lloyd, Graeme T; Mannion, Philip D; Norell, Mark A; Peppe, Daniel J; Upchurch, Paul; Williamson, Thomas E

    2015-05-01

    Non-avian dinosaurs went extinct 66 million years ago, geologically coincident with the impact of a large bolide (comet or asteroid) during an interval of massive volcanic eruptions and changes in temperature and sea level. There has long been fervent debate about how these events affected dinosaurs. We review a wealth of new data accumulated over the past two decades, provide updated and novel analyses of long-term dinosaur diversity trends during the latest Cretaceous, and discuss an emerging consensus on the extinction's tempo and causes. Little support exists for a global, long-term decline across non-avian dinosaur diversity prior to their extinction at the end of the Cretaceous. However, restructuring of latest Cretaceous dinosaur faunas in North America led to reduced diversity of large-bodied herbivores, perhaps making communities more susceptible to cascading extinctions. The abruptness of the dinosaur extinction suggests a key role for the bolide impact, although the coarseness of the fossil record makes testing the effects of Deccan volcanism difficult.

  8. Measuring Galactic Extinction A Test

    CERN Document Server

    Arce, H G; Arce, Hector G.; Goodman, Alyssa A.

    1999-01-01

    We test the recently published all-sky reddening map of Schlegel, Finkbeiner & Davis (1998 [SFD]) using the extinction study of a region in the Taurus dark cloud complex by Arce & Goodman (1999 [AG]). In their study, AG use four different techniques to measure the amount and structure of the extinction toward Taurus, and all four techniques agree very well. Thus we believe that the AG results are a truthful representation of the extinction in the region and can be used to test the reliability of the SFD reddening map. The results of our test show that the SFD all-sky reddening map, which is based on data from COBE/DIRBE and IRAS/ISSA, overestimates the reddening by a factor of 1.3 to 1.5 in regions of smooth extinction with A_V > 0.5 mag. In some regions of steep extinction gradients the SFD map underestimates the reddening value, probably due to its low spatial resolution. We expect that the astronomical community will be using the SFD reddening map extensively. We offer this Letter as a cautionary n...

  9. Multiobjective Gate Assignment Based on Passenger Walking Distance and Fairness

    Directory of Open Access Journals (Sweden)

    Yu Jiang

    2013-01-01

    Full Text Available Passenger walking distance is an important index of the airport service quality. How to shorten the walking distance and balance the airlines' service quality is the focus of much research on airport gate assignment problems. According to the problems of airport passenger service quality, an optimization gate assignment model is established. The gate assignment model is based on minimizing the total walking distance of all passengers and balancing the average walking distance of passengers among different airlines. Lingo is used in the simulation of a large airport gate assignment. Test results show that the optimization model can reduce the average walking distance of passenger effectively, improve the number of flights assigned to gate, balance airline service quality, and enhance the overall service level of airports and airlines. The model provides reference for the airport gate preassignment.

  10. Manikin families representing obese airline passengers in the US.

    Science.gov (United States)

    Park, Hanjun; Park, Woojin; Kim, Yongkang

    2014-01-01

    Aircraft passenger spaces designed without proper anthropometric analyses can create serious problems for obese passengers, including: possible denial of boarding, excessive body pressures and contact stresses, postural fixity and related health hazards, and increased risks of emergency evacuation failure. In order to help address the obese passenger's accommodation issues, this study developed male and female manikin families that represent obese US airline passengers. Anthropometric data of obese individuals obtained from the CAESAR anthropometric database were analyzed through PCA-based factor analyses. For each gender, a 99% enclosure cuboid was constructed, and a small set of manikins was defined on the basis of each enclosure cuboid. Digital human models (articulated human figures) representing the manikins were created using a human CAD software program. The manikin families were utilized to develop design recommendations for selected aircraft seat dimensions. The manikin families presented in this study would greatly facilitate anthropometrically accommodating large airline passengers.

  11. Telemedical advice to long-distance passenger ferries

    DEFF Research Database (Denmark)

    Jensen, Olaf C; Bo Bøggild, Niels; Kristensen, Søren

    2005-01-01

    BACKGROUND: Radio medical (RM) advice for seafarers and traveling passengers is important and can be crucial for the optimal medical treatment on board ships. The aim of this study was to analyze the data from consultations with passenger ferries to identify areas for possible improvements. METHODS......: Data from the journals for 1 year from Radio Medical Denmark consultations with the medical officers on passenger ferries were analyzed retrospectively. RESULTS: Two hundred fourteen RM records, 73% pertaining to passengers and 27% for crew members, were analyzed. Passenger patients were generally...... complaints, and more than half of these involved severe or considerable pain. Only acetaminophen (paracetamol) and opioids were in the ferry medicine chest. At least 77 patients would have benefited from use of nonsteroidal anti-inflammatory drugs. CONCLUSIONS: The paramedical assistance and the medicine...

  12. The atmospheric extinction of light

    CERN Document Server

    Hughes, Stephen W; Powell, Sean; Carroll, Joshua

    2015-01-01

    An experiment is described that enables students to understand the properties of atmospheric extinction due to Rayleigh scattering. The experiment requires the use of red, green and blue lasers attached to a travelling microscope or similar device. The laser beams are passed through an artificial atmosphere, made from milky water, at varying depths, before impinging on either a light meter or a photodiode integral to a Picotech Dr. DAQ ADC. A plot of measured spectral intensity verses depth reveals the contribution Rayleigh scattering has to the extinction coefficient. For the experiment with the light meter, the extinction coefficients for red, green and blue light in the milky sample of water were 0.27, 0.36 and 0.47 cm^-1 respectively and 0.032, 0.037 and 0.092 cm^-1 for the Picotech Dr. DAQ ADC.

  13. Infectious Disease, Endangerment, and Extinction

    Directory of Open Access Journals (Sweden)

    Ross D. E. MacPhee

    2013-01-01

    Full Text Available Infectious disease, especially virulent infectious disease, is commonly regarded as a cause of fluctuation or decline in biological populations. However, it is not generally considered as a primary factor in causing the actual endangerment or extinction of species. We review here the known historical examples in which disease has, or has been assumed to have had, a major deleterious impact on animal species, including extinction, and highlight some recent cases in which disease is the chief suspect in causing the outright endangerment of particular species. We conclude that the role of disease in historical extinctions at the population or species level may have been underestimated. Recent methodological breakthroughs may lead to a better understanding of the past and present roles of infectious disease in influencing population fitness and other parameters.

  14. Mass extinctions and supernova explosions

    CERN Document Server

    Korschinek, Gunther

    2016-01-01

    A nearby supernova (SN) explosion could have negatively influenced life on Earth, maybe even been responsible for mass extinctions. Mass extinction poses a significant extinction of numerous species on Earth, as recorded in the paleontologic, paleoclimatic, and geological record of our planet. Depending on the distance between the Sun and the SN, different types of threats have to be considered, such as ozone depletion on Earth, causing increased exposure to the Sun's ultraviolet radiation, or the direct exposure of lethal x-rays. Another indirect effect is cloud formation, induced by cosmic rays in the atmosphere which result in a drop in the Earth's temperature, causing major glaciations of the Earth. The discovery of highly intensive gamma ray bursts (GRBs), which could be connected to SNe, initiated further discussions on possible life-threatening events in Earth's history. The probability that GRBs hit the Earth is very low. Nevertheless, a past interaction of Earth with GRBs and/or SNe cannot be exclude...

  15. Extinction debt on oceanic islands

    DEFF Research Database (Denmark)

    Triantis, Kostas A.; Borges, Paulo A. V.; Ladle, Richard J.

    2010-01-01

    Habitat destruction is the leading cause of species extinctions. However, there is typically a time-lag between the reduction in habitat area and the eventual disappearance of the remnant populations. These "surviving but ultimately doomed" species represent an extinction debt. Calculating...... the magnitude of such future extinction events has been hampered by potentially inaccurate assumptions about the slope of species-area relationships, which are habitat- and taxon-specific. We overcome this challenge by applying a method that uses the historical sequence of deforestation in the Azorean Islands...... in the last 45 yr, despite the extensive sampling effort, offer support to the predictions made. We argue that immediate action to restore and expand native forest habitat is required to avert the loss of numerous endemic species in the near future...

  16. Habituation, latent inhibition, and extinction.

    Science.gov (United States)

    Jordan, Wesley P; Todd, Travis P; Bucci, David J; Leaton, Robert N

    2015-06-01

    In two conditioned suppression experiments with a latent inhibition (LI) design, we measured the habituation of rats in preexposure, their LI during conditioning, and then extinction over days. In the first experiment, lick suppression, the preexposed group (PE) showed a significant initial unconditioned response (UR) to the target stimulus and significant long-term habituation (LTH) of that response over days. The significant difference between the PE and nonpreexposed (NPE) groups on the first conditioning trial was due solely to the difference in their URs to the conditioned stimulus (CS)-a habituated response (PE) and an unhabituated response (NPE). In the second experiment, bar-press suppression, little UR to the target stimulus was apparent during preexposure, and no detectable LTH. Thus, there was no difference between the PE and NPE groups on the first conditioning trial. Whether the UR to the CS confounds the interpretation of LI (Exp. 1) or not (Exp. 2) can only be known if the UR is measured. In both experiments, LI was observed in acquisition. Also in both experiments, rats that were preexposed and then conditioned to asymptote were significantly more resistant to extinction than were the rats not preexposed. This result contrasts with the consistently reported finding that preexposure either produces less resistance to extinction or has no effect on extinction. The effect of stimulus preexposure survived conditioning to asymptote and was reflected directly in extinction. These two experiments provide a cautionary procedural note for LI experiments and have shown an unexpected extinction effect that may provide new insights into the interpretation of LI.

  17. Histological and global gene expression analysis of the 'lactating' pigeon crop

    Directory of Open Access Journals (Sweden)

    Nicholas Kevin R

    2011-09-01

    Full Text Available Abstract Background Both male and female pigeons have the ability to produce a nutrient solution in their crop for the nourishment of their young. The production of the nutrient solution has been likened to lactation in mammals, and hence the product has been called pigeon 'milk'. It has been shown that pigeon 'milk' is essential for growth and development of the pigeon squab, and without it they fail to thrive. Studies have investigated the nutritional value of pigeon 'milk' but very little else is known about what it is or how it is produced. This study aimed to gain insight into the process by studying gene expression in the 'lactating' crop. Results Macroscopic comparison of 'lactating' and non-'lactating' crop reveals that the 'lactating' crop is enlarged and thickened with two very obvious lateral lobes that contain discrete rice-shaped pellets of pigeon 'milk'. This was characterised histologically by an increase in the number and depth of rete pegs extending from the basal layer of the epithelium to the lamina propria, and extensive proliferation and folding of the germinal layer into the superficial epithelium. A global gene expression profile comparison between 'lactating' crop and non-'lactating' crop showed that 542 genes are up-regulated in the 'lactating' crop, and 639 genes are down-regulated. Pathway analysis revealed that genes up-regulated in 'lactating' crop were involved in the proliferation of melanocytes, extracellular matrix-receptor interaction, the adherens junction and the wingless (wnt signalling pathway. Gene ontology analysis showed that antioxidant response and microtubule transport were enriched in 'lactating' crop. Conclusions There is a hyperplastic response in the pigeon crop epithelium during 'lactation' that leads to localised cellular stress and expression of antioxidant protein-encoding genes. The differentiated, cornified cells that form the pigeon 'milk' are of keratinocyte lineage and contain

  18. Pigeon RIG-I Function in Innate Immunity against H9N2 IAV and IBDV

    Directory of Open Access Journals (Sweden)

    Wenping Xu

    2015-07-01

    Full Text Available Retinoic acid-inducible gene I (RIG-I, a cytosolic pattern recognition receptor (PRR, can sense various RNA viruses, including the avian influenza virus (AIV and infectious bursal disease virus (IBDV, and trigger the innate immune response. Previous studies have shown that mammalian RIG-I (human and mice and waterfowl RIG-I (ducks and geese are essential for type I interferon (IFN synthesis during AIV infection. Like ducks, pigeons are also susceptible to infection but are ineffective propagators and disseminators of AIVs, i.e., “dead end” hosts for AIVs and even highly pathogenic avian influenza (HPAI. Consequently, we sought to identify pigeon RIG-I and investigate its roles in the detection of A/Chicken/Shandong/ZB/2007 (H9N2 (ZB07, Gansu/Tianshui (IBDV TS and Beijing/CJ/1980 (IBDV CJ-801 strains in chicken DF-1 fibroblasts or human 293T cells. Pigeon mRNA encoding the putative pigeon RIG-I analogs was identified. The exogenous expression of enhanced green fluorescence protein (EGFP-tagged pigeon RIG-I and caspase activation and recruitment domains (CARDs, strongly induced antiviral gene (IFN-β, Mx, and PKR mRNA synthesis, decreased viral gene (M gene and VP2 mRNA expression, and reduced the viral titers of ZB07 and IBDV TS/CJ-801 virus strains in chicken DF-1 cells, but not in 293T cells. We also compared the antiviral abilities of RIG-I proteins from waterfowl (duck and goose and pigeon. Our data indicated that waterfowl RIG-I are more effective in the induction of antiviral genes and the repression of ZB07 and IBDV TS/CJ-801 strain replication than pigeon RIG-I. Furthermore, chicken melanoma differentiation associated gene 5(MDA5/ mitochondrial antiviral signaling (MAVS silencing combined with RIG-I transfection suggested that pigeon RIG-I can restore the antiviral response in MDA5-silenced DF-1 cells but not in MAVS-silenced DF-1 cells. In conclusion, these results demonstrated that pigeon RIG-I and CARDs have a strong antiviral

  19. Functions of innate and acquired immune system are reduced in domestic pigeons (Columba livia domestica) given a low protein diet.

    Science.gov (United States)

    Mabuchi, Yuko; Frankel, Theresa L

    2016-03-01

    Racing pigeons are exposed to and act as carriers of diseases. Dietary protein requirement for their maintenance has not been determined experimentally despite their being domesticated for over 7000 years. A maintenance nitrogen (protein) requirement (MNR) for pigeons was determined in a balance study using diets containing 6, 10 and 14% crude protein (CP). Then, the effects of feeding the diets were investigated to determine whether they were adequate to sustain innate and acquired immune functions. Nitrogen intake from the 6% CP diet was sufficient to maintain nitrogen balance and body weight in pigeons. However, the immune functions of phagocytosis, oxidative burst and lymphocyte proliferation in pigeons fed this diet were reduced compared with those fed 10 and 14% CP diets. Pigeons given the 6 and 10% CP diets had lower antibody titres following inoculation against Newcastle disease (ND) than those on the 14% CP diet. A confounding factor found on autopsy was the presence of intestinal parasites in some of the pigeons given the 6 and 10% CP diets; however, none of the pigeons used to measure MNR or acquired immunity to ND were infested with parasites. In conclusion, neither the 6 nor 10% CP diets adequately sustained acquired immune function of pigeons.

  20. Class I Integron and β-lactamase encoding genes of multidrug resistance Salmonella isolated from pigeons and their environments.

    Science.gov (United States)

    Yousef, S; Mamdouh, R

    2016-12-30

    Seroprevalence of Salmonella spp. was investigated in pigeon and its surrounding environment of Sharkia province, Egypt. Samples were randomly collected from fifty freshly dead squabs, forty freshly dead adults pigeons, sixty diseased adult pigeons and 100 apparently healthy adult pigeons. Bacterial isolates were tested for their susceptibility to 17 different antimicrobial discs, by using the disc diffusion method. The bacterial isolates were tested for Class I and β-lactamase encoding genes by using PCR. In vitro sensitivity of all Salmonella isolates were completely resistant to Streptomycin, Amoxicillin, clavulanic acid, Amoxicillin, Ampicillin and Ceftazidime (100%). Class1 integron were characterized in 70% Salmonella isolates from squabs, 42.9 % in adult pigeons and 14.3% in pigeon environment which confer their resistance to streptomycin and ampicillin. Meanwhile TEM-1 β-lactamase was characterized in 20% of tested Salmonella isolates from squabs including S. Entertidis, 42.9% of tested Salmonella isolates from adult pigeons including S. Entertidis which confer their resistance to cephalosporin and not detected in all isolates from pigeons environments. In conclusion TEM-1 β-lactamase was characterized in 20% of Salmonella isolates from squabs while Class1 integron was characterized in 70% Salmonella isolates from squabs.

  1. Extinction risk of soil biota.

    Science.gov (United States)

    Veresoglou, Stavros D; Halley, John M; Rillig, Matthias C

    2015-11-23

    No species lives on earth forever. Knowing when and why species go extinct is crucial for a complete understanding of the consequences of anthropogenic activity, and its impact on ecosystem functioning. Even though soil biota play a key role in maintaining the functioning of ecosystems, the vast majority of existing studies focus on aboveground organisms. Many questions about the fate of belowground organisms remain open, so the combined effort of theorists and applied ecologists is needed in the ongoing development of soil extinction ecology.

  2. Interstellar Grains: Effect of Inclusions on Extinction

    CERN Document Server

    Katyal, Nisha; Vaidya, D B

    2011-01-01

    A composite dust grain model which simultaneously explains the observed interstellar extinction, polarization, IR emission and the abundance constraints, is required. We present a composite grain model, which is made up of a host silicate oblate spheroid and graphite inclusions. The interstellar extinction curve is evaluated in the spectral region 3.4-0.1$\\mu m$ using the extinction efficiencies of the composite spheroidal grains for three axial ratios. Extinction curves are computed using the discrete dipole approximation (DDA). The model curves are subsequently compared with the average observed interstellar extinction curve and with an extinction curve derived from the IUE catalogue data.

  3. Interstellar grains: Effect of inclusions on extinction

    Science.gov (United States)

    Katyal, N.; Gupta, R.; Vaidya, D. B.

    2011-10-01

    A composite dust grain model which simultaneously explains the observed interstellar extinction, polarization, IR emission and the abundance constraints, is required. We present a composite grain model, which is made up of a host silicate oblate spheroid and graphite inclusions. The interstellar extinction curve is evaluated in the spectral region 3.4-0.1 μm using the extinction efficiencies of composite spheroidal grains for three axial ratios. Extinction curves are computed using the discrete dipole approximation (DDA). The model curves are subsequently compared with the average observed interstellar extinction curve and with an extinction curve derived from the IUE catalogue data.

  4. The potential of pigeons as surrogate observers in medical image perception studies

    Science.gov (United States)

    Krupinski, Elizabeth A.; Levenson, Richard M.; Navarro, Victor; Wasserman, Edward A.

    2016-03-01

    Assessment of medical image quality and how changes in image appearance impact performance are critical but assessment can be expensive and time-consuming. Could an animal (pigeon) observer with well-known visual skills and documented ability to distinguish complex visual stimuli serve as a surrogate for the human observer? Using sets of whole slide pathology (WSI) and mammographic images we trained pigeons (cohorts of 4) to detect and/or classify lesions in medical images. Standard training methods were used. A chamber equipped with a 15' display with a resistive touchscreen was used to display the images and record responses (pecks). Pigeon pellets were dispensed for correct responses. The pigeons readily learned to distinguish benign from malignant breast cancer histopathology in WSI (mean % correct responses rose 50% to 85% over 15 days) and generalized readily from 4X to 10X and 20X magnifications; to detect microcalcifications (mean % correct responses rose 50% to over 85% over 25 days); to distinguish benign from malignant breast masses (3 of 4 birds learned this task to around 80% and 60% over 10 days); and ignore compression artifacts in WSI (performance with uncompressed slides averaged 95% correct; 15:1 and 27:1 compression slides averaged 92% and 90% correct). Pigeons models may help us better understand medical image perception and may be useful in quality assessment by serving as surrogate observers for certain types of studies.

  5. DEVELOPMENT AND PERFORMANCE EVALUATION OF TRACTOR FRONT MOUNTED PIGEON PEA STEM CUTTER

    Directory of Open Access Journals (Sweden)

    Atul R. Dange

    2010-07-01

    Full Text Available Pigeon pea or tur (Cajanus cajan L. Mills. is one of the important pulse crops of India and ranks second to chickpea in area and production. Traditionally the harvesting of pigeon pea is done manually by sickle, which demands considerable amount of labour, drudgery, time and cost to harvest, which reflects on total production cost of the crop. In view of this a tractor operated front mounted pigeon pea stem cutter was developed and being front mounted implement it facilitated better visibility and control to operator. The power was transmitted from pto to gear box. Arrangement of hydraulic cylinder and hydraulic motor was provided on the equipment to facilitate the height of cut and to rotate the conveyer belt. During comparative performance evaluation of developed equipment, the average cutting efficiency and field capacity was found 96.30 % and 0.176 ha/hr respectively. There was increase in fuel consumption and plant damage with increase in speed of operation. The average operation cost of newly developed tractor operated front mounted pigeon pea stem cutter was 64.71% less as compared with manual harvesting of pigeon pea crop. The time saved was almost 1/3rd to that of manual harvesting.

  6. Molecular identification of Cryptosporidium spp. in seagulls, pigeons, dogs, and cats in Thailand.

    Science.gov (United States)

    Koompapong, Khuanchai; Mori, Hirotake; Thammasonthijarern, Nipa; Prasertbun, Rapeepun; Pintong, Ai-rada; Popruk, Supaluk; Rojekittikhun, Wichit; Chaisiri, Kittipong; Sukthana, Yaowalark; Mahittikorn, Aongart

    2014-01-01

    Zoonotic Cryptosporidium spp., particularly C. meleagridis, C. canis, and C. felis, are enteric protozoa responsible for major public health concerns around the world. To determine the spread of this parasite in Thailand, we conducted molecular identification of Cryptosporidium spp. from animal samples around the country, by collecting and investigating the feces of seagulls (Chroicocephalus brunnicephalus and Chroicocephalus ridibundus), domestic pigeons (Columba livia domestica), dogs, and cats. Seagull and pigeon samples were collected at the seaside and on the riverside to evaluate their potential for waterborne transmission. Ten pigeon samples were combined into one set, and a total of seven sets were collected. Seventy seagull samples were combined into one set, and a total of 13 sets were collected. In addition, 111 dog samples were collected from cattle farms, and 95 dog and 80 cat samples were collected from a temple. We identified C. meleagridis in pigeons, Cryptosporidium avian genotype III in seagulls, C. canis in dogs, and C. felis in cats. In the temple, the prevalence was 2.1% (2/95) for dogs and 2.5% (2/80) for cats. No Cryptosporidium was found in dog samples from cattle farms. These are the first findings of C. meleagridis in domestic pigeons, and Cryptosporidium avian genotype III in seagulls. Our study invites further molecular epidemiological investigations of Cryptosporidium in these animals and their environment to evaluate the public health risk in Thailand.

  7. Perceptual strategies of pigeons to detect a rotational centre--a hint for star compass learning?

    Directory of Open Access Journals (Sweden)

    Bianca Alert

    Full Text Available Birds can rely on a variety of cues for orientation during migration and homing. Celestial rotation provides the key information for the development of a functioning star and/or sun compass. This celestial compass seems to be the primary reference for calibrating the other orientation systems including the magnetic compass. Thus, detection of the celestial rotational axis is crucial for bird orientation. Here, we use operant conditioning to demonstrate that homing pigeons can principally learn to detect a rotational centre in a rotating dot pattern and we examine their behavioural response strategies in a series of experiments. Initially, most pigeons applied a strategy based on local stimulus information such as movement characteristics of single dots. One pigeon seemed to immediately ignore eccentric stationary dots. After special training, all pigeons could shift their attention to more global cues, which implies that pigeons can learn the concept of a rotational axis. In our experiments, the ability to precisely locate the rotational centre was strongly dependent on the rotational velocity of the dot pattern and it crashed at velocities that were still much faster than natural celestial rotation. We therefore suggest that the axis of the very slow, natural, celestial rotation could be perceived by birds through the movement itself, but that a time-delayed pattern comparison should also be considered as a very likely alternative strategy.

  8. Olfactory lateralization in homing pigeons: a GPS study on birds released with unilateral olfactory inputs.

    Science.gov (United States)

    Gagliardo, Anna; Filannino, Caterina; Ioalè, Paolo; Pecchia, Tommaso; Wikelski, Martin; Vallortigara, Giorgio

    2011-02-15

    A large body of evidence has shown that pigeons rely on an olfactory-based navigational map when homing from unfamiliar locations. Previous studies on pigeons released with one nostril occluded highlighted an asymmetry in favour of the right nostril, particularly concerning the initial orientation performance of naïve birds. Nevertheless, all pigeons experiencing only unilateral olfactory input showed impaired homing, regardless of the side of the occluded nostril. So far this phenomenon has been documented only by observing the birds' vanishing bearings. In the present work we recorded the flight tracks of pigeons with previous homing experience equipped with a GPS data logger and released from an unfamiliar location with the right or the left nostril occluded. The analysis of the tracks revealed that the flight path of the birds with the right nostril occluded was more tortuous than that of unmanipulated controls. Moreover, the pigeons smelling with the left nostril interrupted their journey significantly more frequently and displayed more exploratory activity than the control birds, e.g. during flights around a stopover site. These data suggest a more important involvement of the right olfactory system in processing the olfactory information needed for the operation of the navigational map.

  9. Perceptual strategies of pigeons to detect a rotational centre--a hint for star compass learning?

    Science.gov (United States)

    Alert, Bianca; Michalik, Andreas; Helduser, Sascha; Mouritsen, Henrik; Güntürkün, Onur

    2015-01-01

    Birds can rely on a variety of cues for orientation during migration and homing. Celestial rotation provides the key information for the development of a functioning star and/or sun compass. This celestial compass seems to be the primary reference for calibrating the other orientation systems including the magnetic compass. Thus, detection of the celestial rotational axis is crucial for bird orientation. Here, we use operant conditioning to demonstrate that homing pigeons can principally learn to detect a rotational centre in a rotating dot pattern and we examine their behavioural response strategies in a series of experiments. Initially, most pigeons applied a strategy based on local stimulus information such as movement characteristics of single dots. One pigeon seemed to immediately ignore eccentric stationary dots. After special training, all pigeons could shift their attention to more global cues, which implies that pigeons can learn the concept of a rotational axis. In our experiments, the ability to precisely locate the rotational centre was strongly dependent on the rotational velocity of the dot pattern and it crashed at velocities that were still much faster than natural celestial rotation. We therefore suggest that the axis of the very slow, natural, celestial rotation could be perceived by birds through the movement itself, but that a time-delayed pattern comparison should also be considered as a very likely alternative strategy.

  10. Pigeons (Columba livia) fail to connect dots in learning biological motion.

    Science.gov (United States)

    Yamamoto, Eriko; Goto, Kazuhiro; Watanabe, Shigeru

    2015-09-01

    Biological motion point-light displays provide a powerful method for studying motion perception. Nonhuman animals are capable of discriminating point-light displays, but it remains unknown how they perceive biological motion in these displays. We trained two groups of pigeons to discriminate video stimuli using two different classification rules. The motion-congruent group was trained to discriminate full-detail and corresponding point-light displays of pigeons from full-detail and point-light displays of humans. The motion-incongruent group was trained to discriminate full-detail pigeons and point-light humans from the other displays. Both groups acquired the discrimination. When tested with novel displays, pigeons showed good transfer of learning. Transfer was poorest with the point-light displays in the motion-congruent group. The results indicate that the pigeons failed to make the connection between the full-detail displays and their point-light counterparts even when the common motion was available as a cue.

  11. Physiological and hormonal aspects in female domestic pigeons (Columba livia) associated with breeding stage and experience.

    Science.gov (United States)

    Dong, X Y; Zhang, M; Jia, Y X; Zou, X T

    2013-10-01

    The present study examined the changes in serum biochemical values, hormone profiles and ovary prolactin receptor (PRLR) gene expression occurring in female domestic pigeons (Columba livia) under different breeding status and experience. The egg-laying pigeons had lower calcium, total protein, albumin, prolactin levels and higher oestrogen levels than those of incubating birds (p < 0.05). First-time breeders had higher (p < 0.05) progesterone levels and lower (p < 0.05) prolactin levels than that of experienced ones. The levels of oestrogen and follicle-stimulating hormone (FSH) increased with age (p < 0.05). The very old birds showed a pronounced increase (p < 0.05) in PRL, FSH and progesterone and a little decrease in oestrogen. Serum prolactin level was not correlated with the ovary PRLR mRNA expression pattern among all the pigeons. Results showed that serum physiological profile of female pigeons was correlated with breeding status, whereas reproductive hormone levels were correlated with advancing breeding experience. It was concluded that female pigeons had a good ability of recovering from nutrient loss after each breeding attempts, and the degradation of reproductive performance might be attributed to changes in the endocrine system.

  12. Magnetic field-driven induction of ZENK in the trigeminal system of pigeons (Columba livia).

    Science.gov (United States)

    Lefeldt, Nele; Heyers, Dominik; Schneider, Nils-Lasse; Engels, Svenja; Elbers, Dana; Mouritsen, Henrik

    2014-11-01

    Magnetoreception remains one of the few unsolved mysteries in sensory biology. The upper beak, which is innervated by the ophthalmic branch of the trigeminal nerve (V1), has been suggested to contain magnetic sensors based on ferromagnetic structures. Recently, its existence in pigeons has been seriously challenged by studies suggesting that the previously described iron-accumulations are macrophages, not magnetosensitive nerve endings. This raised the fundamental question of whether V1 is involved in magnetoreception in pigeons at all. We exposed pigeons to either a constantly changing magnetic field (CMF), to a zero magnetic field providing no magnetic information, or to CMF conditions after V1 was cut bilaterally. Using immediate early genes as a marker of neuronal responsiveness, we report that the trigeminal brainstem nuclei of pigeons, which receive V1 input, are activated under CMF conditions and that this neuronal activation disappears if the magnetic stimuli are removed or if V1 is cut. Our data suggest that the trigeminal system in pigeons is involved in processing magnetic field information and that V1 transmits this information from currently unknown, V1-associated magnetosensors to the brain.

  13. Molecular identification of Cryptosporidium spp. in seagulls, pigeons, dogs, and cats in Thailand

    Directory of Open Access Journals (Sweden)

    Koompapong Khuanchai

    2014-01-01

    Full Text Available Zoonotic Cryptosporidium spp., particularly C. meleagridis, C. canis, and C. felis, are enteric protozoa responsible for major public health concerns around the world. To determine the spread of this parasite in Thailand, we conducted molecular identification of Cryptosporidium spp. from animal samples around the country, by collecting and investigating the feces of seagulls (Chroicocephalus brunnicephalus and Chroicocephalus ridibundus, domestic pigeons (Columba livia domestica, dogs, and cats. Seagull and pigeon samples were collected at the seaside and on the riverside to evaluate their potential for waterborne transmission. Ten pigeon samples were combined into one set, and a total of seven sets were collected. Seventy seagull samples were combined into one set, and a total of 13 sets were collected. In addition, 111 dog samples were collected from cattle farms, and 95 dog and 80 cat samples were collected from a temple. We identified C. meleagridis in pigeons, Cryptosporidium avian genotype III in seagulls, C. canis in dogs, and C. felis in cats. In the temple, the prevalence was 2.1% (2/95 for dogs and 2.5% (2/80 for cats. No Cryptosporidium was found in dog samples from cattle farms. These are the first findings of C. meleagridis in domestic pigeons, and Cryptosporidium avian genotype III in seagulls. Our study invites further molecular epidemiological investigations of Cryptosporidium in these animals and their environment to evaluate the public health risk in Thailand.

  14. Narrowing down the conditions for extinction of Pavlovian feature-positive discriminations in humans.

    Science.gov (United States)

    van Vooren, Priya R; Franssen, Mathijs; Beckers, Tom; Hermans, Dirk; Baeyens, Frank

    2012-12-01

    The aim of this study was to delineate the minimal conditions for extinction of Pavlovian modulation in humans. Previous experiments at our lab showed that, after X-- A+/A- acquisition training, X- trials did not extinguish differential X-- A+/A- responding, while X-- A- trials did. Additionally, X-- A- extinction training seemed only to extinguish differential X-- A+/A- responding, while leaving differential responding on a concurrently trained Y [Symbol: see text] B+/B- discrimination intact. It thus seemed that the X-- A+/A- discrimination can only be extinguished by X-- A- extinction trials. (Rescorla, Journal of Experimental Psychology: Animal Behavior Processes 12, 16-24, 1986), on the other hand, found that the minimal conditions for extinction were broader in pigeons: Namely, he found that an acquired X-- A+/A- discrimination could be extinguished by presenting the original feature X in combination with a different target (B) that was minimally trained as an exciter. We thus wanted to examine whether this was also the case in humans. We found that nonreinforced X-- B- presentations did not abolish discriminative X-- A/A responding when target B was a nonreinforced stimulus. Nonreinforced X-- B- trials did extinguish the X-- A+/A- discrimination when target B had previously been trained as a target for modulation (X-- B+/B- or Y [Symbol: see text] B+/B- training) or as a reinforced exciter (B+). Our results thusf parallel and extend those in nonhuman animals (Rescorla, Journal of Experimental Psychology: Animal Behavior Processes 12, 16-24, 1986).

  15. Afferent innervation of the utricular macula in pigeons

    Science.gov (United States)

    Si, Xiaohong; Zakir, Mridha Md; Dickman, J. David

    2003-01-01

    Biotinylated dextran amine (BDA) was used to retrogradely label afferents innervating the utricular macula in adult pigeons. The pigeon utriclar macula consists of a large rectangular-shaped neuroepithelium with a dorsally curved anterior edge and an extended medioposterior tail. The macula could be demarcated into several regions based on cytoarchitectural differences. The striola occupied 30% of the macula and contained a large density of type I hair cells with fewer type II hair cells. Medial and lateral extrastriola zones were located outside the striola and contained only type II hair cells. A six- to eight-cell-wide band of type II hair cells existed near the center of the striola. The reversal line marked by the morphological polarization of hair cells coursed throughout the epithelium, near the peripheral margin, and through the center of the type II band. Calyx afferents innervated type I hair cells with calyceal terminals that contained between 2 and 15 receptor cells. Calyx afferents were located only in the striola region, exclusive of the type II band, had small total fiber innervation areas and low innervation densities. Dimorph afferents innervated both type I and type II hair cells with calyceal and bouton terminals and were primarily located in the striola region. Dimorph afferents had smaller calyceal terminals with few type I hair cells, extended fiber branches with bouton terminals and larger innervation areas. Bouton afferents innervated only type II hair cells in the extrastriola and type II band regions. Bouton afferents innervating the type II band had smaller terminal fields with fewer bouton terminals and smaller innervation areas than fibers located in the extrastriolar zones. Bouton afferents had the most bouton terminals on the longest fibers, the largest innervation areas with the highest innervation densities of all afferents. Among all afferents, smaller terminal innervation fields were observed in the striola and large fields were

  16. Is passenger vehicle incompatibility still a problem?

    Science.gov (United States)

    Teoh, Eric R; Nolan, Joseph M

    2012-01-01

    Passenger cars often are at a disadvantage when colliding with light trucks (sport utility vehicles [SUVs] and pickups) due to differences in mass, vehicle structural alignment, and stiffness. In 2003, vehicle manufacturers agreed to voluntary measures to improve compatibility, especially in front-to-front and front-to-side crashes, with full adherence to be achieved by September 2009. This study examined whether fatality rates are consistent with the expected benefit of this agreement. Analyses examined 2 death rates for 1- to 4-year-old passenger vehicles during 2000-2001 and 2008-2009 in the United States: occupant deaths per million registered vehicle years in these vehicles and deaths in other cars that collided with these vehicles in 2-vehicle crashes per million registered vehicle years. These rates were computed for each study period and for cars/minivans (referred to as cars), SUVs, and pickups by curb weight (in 500-pound increments). The latter death rate, referred to as the car crash partner death rate, also was computed for front-to-front crashes and front-to-side crashes where the front of the 1- to 4-year-old vehicle struck the side of the partner car. In both study periods, occupant death rates generally decreased for each vehicle type both with increasing curb weight and over time. SUVs experienced the greatest declines compared with cars and pickups. This is due in part to the early fitment of electronic stability control in SUVs, which drastically reduced the incidence of single-vehicle rollover crashes. Pickups had the highest death rates in both study periods. Car crash partner death rates generally declined over time for all vehicle categories but more steeply for SUVs and pickups colliding with cars than for cars colliding with cars. In fact, the car crash partner death rates for SUVs and cars were nearly identical during 2008-2009, suggesting that the voluntary design changes for compatibility have been effective. Car crash partner death

  17. Relevance and treatment of coccidiosis in domestic pigeons (Columba livia forma domestica) with particular emphasis on toltrazuril.

    Science.gov (United States)

    Krautwald-Junghanns, Maria-Elisabeth; Zebisch, Ralph; Schmidt, Volker

    2009-03-01

    Coccidia are common pathogenic parasites in pigeons (Columba livia). Coccidiosis is most commonly seen in young pigeons and only rarely in adult birds. Infections in domestic pigeons are typically mixed and commonly include Eimeria columbarum and Eimeria labbeana. The reported prevalence of infection is 5.1%-71.9%, and worldwide mortality in juvenile pigeons varies from 5% to 70%, with most deaths occurring in the third and fourth month of life. This article summarizes the life cycle of E. columbarum and E. labbeana, the route of transmission, and the common clinical and pathologic signs of coccidiosis. Chemotherapeutic options discussed include amprolium, sulfonamides, clazuril, and toltrazuril. Reasons to use toltrazuril include the growing resistance against other drugs, such as sulfonamides and amprolium, the extended effectiveness compared with other substances, for example, clazuril, and the ability of pigeons to develop immunity during treatment.

  18. A 3-dimensional digital atlas of the ascending sensory and the descending motor systems in the pigeon brain.

    Science.gov (United States)

    Güntürkün, Onur; Verhoye, Marleen; De Groof, Geert; Van der Linden, Annemie

    2013-01-01

    Pigeons are classic animal models for learning, memory, and cognition. The majority of the current understanding about avian neurobiology outside of the domain of the song system has been established using pigeons. Since MRI represents an increasingly relevant tool for comparative neuroscience, a 3-dimensional MRI-based atlas of the pigeon brain becomes essential. Using multiple imaging protocols, we delineated diverse ascending sensory and descending motor systems as well as the hippocampal formation. This pigeon brain atlas can easily be used to determine the stereotactic location of identified neural structures at any angle of the head. In addition, the atlas is useful to find the optimal angle of sectioning for slice experiments, stereotactic injections and electrophysiological recordings. This pigeon brain atlas is freely available for the scientific community.

  19. Endangered and Extinct Radioactivity

    Science.gov (United States)

    Leising, M. D.

    1993-07-01

    Gamma ray spectroscopy holds great promise for probing nucleosynthesis in individual nucleosynthesis events, via observations of short-lived radioactivity, and for measuring global galactic nucleosynthesis today with detections of longer-lived radioactivity. Many of the astrophysical issues addressed by these observations are precisely those that must be understood in order to interpret observations of extinct radioactivity in meteorites. It was somewhat surprising that the former case was realized first for a Type II supernova, when both 56Co [1] and 57Co [2] were detected in SN 1987A. These provide unprecedented constraints on models of Type II explosions. Live 26Al in the galaxy might come from Type II supernovae and their progenitors, and if this is eventually shown to be the case, can constrain massive star evolution, supernova nucleosynthesis, the galactic Type II supernova rate, and even models of the chemical evolution of the galaxy [3]. Titanium-44 is produced primarily in the alpha-rich freezeout from nuclear statistical equilibrium, possibly in Type Ia [4] and almost certainly in Type II supernovae [5]. The galactic recurrence time of these events is comparable to the 44Ti lifetime, so we expect to be able to see at most a few otherwise unseen 44Ti remnants at any given time. No such remnants have been detected yet [6]. Very simple arguments lead to the expectation that about 4 x 10^-4 M(sub)solar mass of 44Ca are produced per century. The product of the supernova frequency times the 44Ti yield per event must equal this number. Even assuming that only the latest event would be seen, rates in excess of 2 century^-1 are ruled out at >=99% confidence by the gamma ray limits. Only rates less than 0.3 century^-1 are acceptable at >5% confidence, and this means that the yield per event must be >10^-3 M(sub)solar mass to produce the requisite 44Ca. Rates this low are incompatible with current estimates for Type II supernovae and yields this high are also very

  20. Swiss fuel cell passenger and pleasure boats

    Energy Technology Data Exchange (ETDEWEB)

    Affolter, J.-F.

    2000-07-01

    This paper published by the University of Applied Science in Yverdon-les-Bains, Switzerland, looks at the development of electrically driven small boats that are powered by fuel cells. The various implementations of the test boats are described. Starting with a 100-watt PEM fuel cell built by the Paul Scherrer Institute (PSI) and the University of Applied Science in Solothurn, Switzerland, for educational purposes, a small pedal-boat was electrified. The paper describes the development of four further prototypes and introduces a new project for a 6-passenger leisure boat powered by a 2 kW PEFC fuel cell. Apart from the fuel cells, various other components such as propellers and control electronics are discussed as are the remaining problems still to be solved before the cells and boats can be marketed. Since they were carried out at a technical university, these projects are said to have provided an excellent way of teaching new technologies to students.

  1. Inferring Passenger Type from Commuter Eigentravel Matrices

    CERN Document Server

    Legara, Erika Fille

    2015-01-01

    A sufficient knowledge of the demographics of a commuting public is essential in formulating and implementing more targeted transportation policies, as commuters exhibit different ways of traveling. With the advent of the Automated Fare Collection system (AFC), probing the travel patterns of commuters has become less invasive and more accessible. Consequently, numerous transport studies related to human mobility have shown that these observed patterns allow one to pair individuals with locations and/or activities at certain times of the day. However, classifying commuters using their travel signatures is yet to be thoroughly examined. Here, we contribute to the literature by demonstrating a procedure to characterize passenger types (Adult, Child/Student, and Senior Citizen) based on their three-month travel patterns taken from a smart fare card system. We first establish a method to construct distinct commuter matrices, which we refer to as eigentravel matrices, that capture the characteristic travel routines...

  2. Disruption Management in Passenger Railway Transportation

    DEFF Research Database (Denmark)

    Groth, Julie Jespersen; Potthoff, Daniel; Clausen, Jens

    2009-01-01

    This paper deals with disruption management in passenger railway transportation. In the disruption management process, many actors belonging to different organizations play a role. In this paper we therefore describe the process itself and the roles of the different actors. Furthermore, we discuss...... the three main subproblems in railway disruption management: timetable adjustment, and rolling stock and crew re-scheduling. Next to a general description of these problems, we give an overview of the existing literature and we present some details of the specific situations at DSB S-tog and NS....... These are the railway operators in the suburban area of Copenhagen, Denmark, and on the main railway lines in The Netherlands, respectively. Finally, we address the integration of the re-scheduling processes of the timetable, and the resources rolling stock and crew....

  3. Disruption Management in Passenger Railway Transportation

    DEFF Research Database (Denmark)

    Jespersen-Groth, Julie; Potthoff, Daniel; Clausen, Jens

    This paper deals with disruption management in passenger railway transportation. In the disruption management process, many actors belonging to different organizations play a role. In this paper we therefore describe the process itself and the roles of the different actors. Furthermore, we discuss...... the three main subproblems in railway disruption management: timetable adjustment, and rolling stock and crew re-scheduling. Next to a general description of these problems, we give an overview of the existing literature and we present some details of the specific situations at DSB S-tog and NS....... These are the railway operators in the suburban area of Copenhagen, Denmark, and on the main railway lines in the Netherlands, respectively. Since not much research has been carried out yet on Operations Research models for disruption management in the railway context, models and techniques that have been developed...

  4. A model of mass extinction

    CERN Document Server

    Newman, M E J

    1997-01-01

    A number of authors have in recent years proposed that the processes of macroevolution may give rise to self-organized critical phenomena which could have a significant effect on the dynamics of ecosystems. In particular it has been suggested that mass extinction may arise through a purely biotic mechanism as the result of so-called coevolutionary avalanches. In this paper we first explore the empirical evidence which has been put forward in favor of this conclusion. The data center principally around the existence of power-law functional forms in the distribution of the sizes of extinction events and other quantities. We then propose a new mathematical model of mass extinction which does not rely on coevolutionary effects and in which extinction is caused entirely by the action of environmental stresses on species. In combination with a simple model of species adaptation we show that this process can account for all the observed data without the need to invoke coevolution and critical processes. The model al...

  5. Extinction debt on oceanic islands

    DEFF Research Database (Denmark)

    Triantis, K.A.; Borges, Paulo A. V.; Ladle, R.J.;

    2010-01-01

    the magnitude of such future extinction events has been hampered by potentially inaccurate assumptions about the slope of species-area relationships, which are habitat- and taxon-specific. We overcome this challenge by applying a method that uses the historical sequence of deforestation in the Azorean Islands...

  6. Change detection and change blindness in pigeons (Columba livia).

    Science.gov (United States)

    Herbranson, Walter T; Trinh, Yvan T; Xi, Patricia M; Arand, Mark P; Barker, Michael S K; Pratt, Theodore H

    2014-05-01

    Change blindness is a phenomenon in which even obvious details in a visual scene change without being noticed. Although change blindness has been studied extensively in humans, we do not yet know if it is a phenomenon that also occurs in other animals. Thus, investigation of change blindness in a nonhuman species may prove to be valuable by beginning to provide some insight into its ultimate causes. Pigeons learned a change detection task in which pecks to the location of a change in a sequence of stimulus displays were reinforced. They were worse at detecting changes if the stimulus displays were separated by a brief interstimulus interval, during which the display was blank, and this primary result matches the general pattern seen in previous studies of change blindness in humans. A second experiment attempted to identify specific stimulus characteristics that most reliably produced a failure to detect changes. Change detection was more difficult when interstimulus intervals were longer and when the change was iterated fewer times.

  7. The contribution of monocular depth cues to scene perception by pigeons.

    Science.gov (United States)

    Cavoto, Brian R; Cook, Robert G

    2006-07-01

    The contributions of different monocular depth cues to performance of a scene perception task were investigated in 4 pigeons. They discriminated the sequential depth ordering of three geometric objects in computer-rendered scenes. The orderings of these objects were specified by the combined presence or absence of the pictorial cues of relative density, occlusion, and relative size. In Phase 1, the pigeons learned the task as a direct function of the number of cues present. The three monocular cues contributed equally to the discrimination. Phase 2 established that differential shading on the objects provided an additional discriminative cue. These results suggest that the pigeon visual system is sensitive to many of the same monocular depth cues that are known to be used by humans. The theoretical implications for a comparative psychology of picture processing are considered.

  8. Pigeons use low rather than high spatial frequency information to make visual category discriminations.

    Science.gov (United States)

    Lea, Stephen E G; De Filippo, Guido; Dakin, Ruth; Meier, Christina

    2013-10-01

    Pigeons were trained to discriminate photographs of cat faces from dog faces. They were then presented with test stimuli involving high- and low-pass spatial frequency filtering. Discrimination was maintained with both types of filtered stimuli, though it was increasingly impaired the more information was filtered out, and high-pass filtering impaired discrimination more than low-pass filtering. The pigeons were then exposed to hybrid stimuli in which high-pass filtered dog faces were combined with low-pass filtered cat faces, and vice versa. Response to hybrid stimuli was determined more by the low spatial frequency content than by the high-frequency content, whereas humans viewing the same stimuli at corresponding viewing distance respond more strongly to the high-frequency content. These results are unexpected given that, compared with humans, pigeons' behavior tends to be controlled by the local details of visual stimuli rather than their global appearance.

  9. A robo-pigeon based on an innovative multi-mode telestimulation system.

    Science.gov (United States)

    Yang, Junqing; Huai, Ruituo; Wang, Hui; Lv, Changzhi; Su, Xuecheng

    2015-01-01

    In this paper, we describe a new multi-mode telestimulation system for brain-microstimulation for the navigation of a robo-pigeon, a new type of bio-robot based on Brain-Computer Interface (BCI) techniques. The multi-mode telestimulation system overcomes neuron adaptation that was a key shortcoming of the previous single-mode stimulation by the use of non-steady TTL biphasic pulses accomplished by randomly alternating pulse modes. To improve efficiency, a new behavior model ("virtual fear") is proposed and applied to the robo-pigeon. Unlike the previous "virtual reward" model, the "virtual fear" behavior model does not require special training. The performance and effectiveness of the system to alleviate the adaptation of neurons was verified by a robo-pigeon navigation test, simultaneously confirming the practicality of the "virtual fear" behavioral model.

  10. An age-related deficit in spatial-feature reference memory in homing pigeons (Columba livia).

    Science.gov (United States)

    Coppola, Vincent J; Flaim, Mary E; Carney, Samantha N; Bingman, Verner P

    2015-03-01

    Age-related memory decline in mammals has been well documented. By contrast, very little is known about memory decline in birds as they age. In the current study we trained younger and older homing pigeons on a reference memory task in which a goal location could be encoded by spatial and feature cues. Consistent with a previous working memory study, the results revealed impaired acquisition of combined spatial-feature reference memory in older compared to younger pigeons. Following memory acquisition, we used cue-conflict probe trials to provide an initial assessment of possible age-related differences in cue preference. Both younger and older pigeons displayed a similarly modest preference for feature over spatial cues.

  11. The complete mitochondrial genome of the Feral Rock Pigeon (Columba livia breed feral).

    Science.gov (United States)

    Li, Chun-Hong; Liu, Fang; Wang, Li

    2014-10-01

    Abstract In the present work, we report the complete mitochondrial genome sequence of feral rock pigeon for the first time. The total length of the mitogenome was 17,239 bp with the base composition of 30.3% for A, 24.0% for T, 31.9% for C, and 13.8% for G and an A-T (54.3 %)-rich feature was detected. It harbored 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and 1 non-coding control region (D-loop region). The arrangement of all genes was identical to the typical mitochondrial genomes of pigeon. The complete mitochondrial genome sequence of feral rock pigeon would serve as an important data set of the germplasm resources for further study.

  12. An outbreak of toxoplasmosis in an aviary collection of Nicobar pigeons (Caloenas nicobaria : clinical communication

    Directory of Open Access Journals (Sweden)

    R.D. Last

    2008-05-01

    Full Text Available Three out of 10 Nicobar pigeons (Caloenas nicobaria in an aviary collection in South Africa were found dead with no presenting clinical symptoms. Histological examination of formalin-fixed tissues from all these birds revealed necrotic foci in various visceral organs (liver, spleen, heart, kidney and lungs, plus diffuse pulmonary congestion and oedema with vasculitis. Numerous protozoal tachyzoites were present in all organs and there was strong positive immunohistochemical (IHC labelling of these organisms for Toxoplasma gondii. Pathology was consistent with acute systemic toxoplasmosis as a consequence of oocyst ingestion. Feral cats were known to be a problem at the facility. Clinical toxoplasmosis is rarely reported in pigeons and this is believed to be the 1st report of toxoplasmosis in Nicobar pigeons.

  13. When good pigeons make bad decisions: Choice with probabilistic delays and outcomes.

    Science.gov (United States)

    Pisklak, Jeffrey M; McDevitt, Margaret A; Dunn, Roger M; Spetch, Marcia L

    2015-11-01

    Pigeons chose between an (optimal) alternative that sometimes provided food after a 10-s delay and other times after a 40-s delay and another (suboptimal) alternative that sometimes provided food after 10 s but other times no food after 40 s. When outcomes were not signaled during the delays, pigeons strongly preferred the optimal alternative. When outcomes were signaled, choices of the suboptimal alternative increased and most pigeons preferred the alternative that provided no food after the long delay despite the cost in terms of obtained food. The pattern of results was similar whether the short delays occurred on 25% or 50% of the trials. Shortening the 40-s delay to food sharply reduced suboptimal choices, but shortening the delay to no food had little effect. The results suggest that a signaled delay to no food does not punish responding in probabilistic choice procedures. The findings are discussed in terms of conditioned reinforcement by signals for good news.

  14. Interstellar Extinction by Spheroidal Dust Grains

    OpenAIRE

    Gupta, Ranjan; Mukai, Tadashi; Vaidya, D. B.; Sen, Asoke K.; Okada, Yasuhiko

    2005-01-01

    Observations of interstellar extinction and polarization indicate that the interstellar medium consists of aligned non-spherical dust grains which show variation in the interstellar extinction curve for wavelengths ranging from NIR to UV. To model the extinction and polarization, one cannot use the Mie theory which assumes the grains as solid spheres. We have used a T-matrix based method for computing the extinction efficiencies of spheroidal silicate and graphite grains of different shapes (...

  15. Passenger Flow Forecast Algorithm for Urban Rail Transit

    Directory of Open Access Journals (Sweden)

    Li Shao Wei

    2013-09-01

    Full Text Available To exactly forecast the urban rail transit passenger flow, a multi-level model combining neural network and Kalman filter was proposed. Firstly, ELAN neural network model was introduced to implement a preliminary forecast of the passenger flow. Then the Kalman filter was used to correct the preliminary forecast results, so as to further improve the accuracy. Finally, in order to validate the proposed model, the passenger flow in Shanghai subway transport hub was observed and simulated. Experimental results showed that the proposed multi-level model reduced error by about 0.8% and had better actual effect compared with any single algorithm.

  16. The Simultaneous Vehicle Scheduling and Passenger Service Problem

    DEFF Research Database (Denmark)

    Petersen, Hanne Løhmann; Larsen, Allan; Madsen, Oli B.G.;

    2013-01-01

    , by modifying the timetable. The planning approach is referred to as the simultaneous vehicle scheduling and passenger service problem (SVSPSP). The SVSPSP is modelled as an integer programming problem and solved using a large neighborhood search metaheuristic. The proposed framework is tested on data inspired......Passengers using public transport systems often experience waiting times when transferring between two scheduled services. In this paper we propose a planning approach that seeks to obtain a favourable trade-off between the two contrasting objectives, passenger service and operating cost...

  17. Generalization of the disruptive effects of alternative stimuli when combined with target stimuli in extinction.

    Science.gov (United States)

    Podlesnik, Christopher A; Miranda-Dukoski, Ludmila; Jonas Chan, C K; Bland, Vikki J; Bai, John Y H

    2017-09-01

    Differential-reinforcement treatments reduce target problem behavior in the short term but at the expense of making it more persistent long term. Basic and translational research based on behavioral momentum theory suggests that combining features of stimuli governing an alternative response with the stimuli governing target responding could make target responding less persistent. However, changes to the alternative stimulus context when combining alternative and target stimuli could diminish the effectiveness of the alternative stimulus in reducing target responding. In an animal model with pigeons, the present study reinforced responding in the presence of target and alternative stimuli. When combining the alternative and target stimuli during extinction, we altered the alternative stimulus through changes in line orientation. We found that (1) combining alternative and target stimuli in extinction more effectively decreased target responding than presenting the target stimulus on its own; (2) combining these stimuli was more effective in decreasing target responding trained with lower reinforcement rates; and (3) changing the alternative stimulus reduced its effectiveness when it was combined with the target stimulus. Therefore, changing alternative stimuli (e.g., therapist, clinical setting) during behavioral treatments that combine alternative and target stimuli could reduce the effectiveness of those treatments in disrupting problem behavior. © 2017 Society for the Experimental Analysis of Behavior.

  18. Further Evidence of Auditory Extinction in Aphasia

    Science.gov (United States)

    Marshall, Rebecca Shisler; Basilakos, Alexandra; Love-Myers, Kim

    2013-01-01

    Purpose: Preliminary research ( Shisler, 2005) suggests that auditory extinction in individuals with aphasia (IWA) may be connected to binding and attention. In this study, the authors expanded on previous findings on auditory extinction to determine the source of extinction deficits in IWA. Method: Seventeen IWA (M[subscript age] = 53.19 years)…

  19. Determining Extinction Ratio Of A Laser Diode

    Science.gov (United States)

    Unger, Glenn L.

    1992-01-01

    Improved technique to determine extinction ratio of pulsed laser diode based partly on definition of extinction ratio applicable to nonideal laser pulses. Heretofore, determinations involved assumption of ideal laser pulses, and neglected optical power from background light. Because power fluctuates during real pulse, more realistic to define extinction ratio in terms of energy obtained.

  20. Hunting and conservation of forest pigeons in São Tomé (West Africa)

    OpenAIRE

    Carvalho, Mariana Bastos

    2015-01-01

    Doutoramento em Biologia - Instituto Superior de Agronomia On the island of São Tomé, four endemic species of fruit pigeons are hunted as food and/or as an economic resource. This thesis intended to collect and analyze the baseline data required for the management of pigeons, which take into account their importance as a resource but also their overall conservation value. For this, I used a combination of biological and social sampling methods. The results show that harvest of endemic pige...

  1. Effects of hormonal priming on seed germination of pigeon pea under cadmium stress.

    Science.gov (United States)

    Sneideris, Larissa C; Gavassi, Marina A; Campos, Marcelo L; D'Amico-Damião, Victor; Carvalho, Rogério F

    2015-09-01

    In this work we investigated whether priming with auxin, cytokinin, gibberellin, abscisic acid and ethylene, alters the physiological responses of seeds of pigeon pea germinated under water and cadmium stress. Seeds treated with water or non-treated seeds were used as control. Although compared to non-treated seeds we found that the hormone treatments improve the germination of pigeon pea under cadmium stress, however, these treatments did not differ from water. However, we also observed a trend of tolerance to the effects of cadmium in the presence of ethylene, suggesting that the use of this hormone may be an efficient method to overcome seed germination under metal stress.

  2. Regulation of bile duct motility by vagus and sympathetic nerves in the pigeon.

    Directory of Open Access Journals (Sweden)

    Neya,Toshiaki

    1990-04-01

    Full Text Available Effects of stimulation of the vagus and sympathetic nerves on bile duct peristalses were studied in pigeons anesthetized with urethane. Vagus stimulation increased the frequency of peristalses. Atropine, hexamethonium and tetrodotoxin abolished this excitatory effect. After atropine, inhibition of peristalses sensitive to tetrodotoxin was produced. Stimulation of sympathetic area in the spinal cord inhibited peristalses. Propranolol converted this effect into an excitatory one, which was abolished by phentolamine. The results suggest that vagal and sympathetic innervations of the bile duct in pigeons are similar to those of the sphincter of Oddi in mammalian species.

  3. Changes of endolymphatic pressure in the semicircular canal of pigeon by caloric stimulation

    Science.gov (United States)

    Wada, Y.; Suzuki, H.; Watanabe, S.

    1994-08-01

    It gets into difficult to explain the mechanism of caloric nystagmus only by convection theory from results of microgravity experiments. One of the other theories is an occurrence of a relative volume change due to a temperature change. Since the volume change must lead to a pressure change after caloric stimulation, we tried to measure the ampulla pressure of the horizontal semicircular canal in pigeons (Columba livia) using an improved servo micropipette system. The main result was that the ampulla pressure increased by cooling and decreased by heating. The changes of the ampulla pressure depended on the temperature change but were not influenced by the pigeon's head position.

  4. Effects of hormonal priming on seed germination of pigeon pea under cadmium stress

    Directory of Open Access Journals (Sweden)

    LARISSA C. SNEIDERIS

    2015-09-01

    Full Text Available In this work we investigated whether priming with auxin, cytokinin, gibberellin, abscisic acid and ethylene, alters the physiological responses of seeds of pigeon pea germinated under water and cadmium stress. Seeds treated with water or non-treated seeds were used as control. Although compared to non-treated seeds we found that the hormone treatments improve the germination of pigeon pea under cadmium stress, however, these treatments did not differ from water. However, we also observed a trend of tolerance to the effects of cadmium in the presence of ethylene, suggesting that the use of this hormone may be an efficient method to overcome seed germination under metal stress.

  5. 75 FR 42115 - Agency Information Collection Activities: Passenger and Crew Manifest

    Science.gov (United States)

    2010-07-20

    ... concerning the Passenger and Crew Manifest (Advance Passenger Information System-APIS). This request for... Manifest (Advance Passenger Information System-APIS). OMB Number: 1651-0088. Form Number: None. Abstract: The Advance Passenger Information System (APIS) is an automated method in which U.S. Customs and...

  6. 78 FR 55279 - Agency Information Collection Activities: Passenger and Crew Manifest

    Science.gov (United States)

    2013-09-10

    ... the Passenger and Crew Manifest (Advance Passenger Information System). This request for comment is... Manifest (Advance Passenger Information System) OMB Number: 1651-0088 Form Number: None Abstract: The Advance Passenger Information System (APIS) is an automated method in which U.S. Customs and Border...

  7. Biological and Phylogenetic Characterization of Pigeon Paramyxovirus Serotype 1 Circulating in Wild North American Pigeons and Doves▿

    Science.gov (United States)

    Kim, L. Mia; King, Daniel J.; Guzman, Hilda; Tesh, Robert B.; da Rosa, Amelia P. A. Travassos; Bueno, Rudy; Dennett, James A.; Afonso, Claudio L.

    2008-01-01

    As part of West Nile virus surveillance programs in Rhode Island and eastern Texas between 2000 and 2007, brain tissue was collected from 5,608 dead birds representing 21 avian orders found in public places or reported by homeowners. Fifteen Newcastle disease virus isolates were recovered only from birds of the order Columbiformes and were positively identified by the USDA-validated real-time reverse transcription-PCR assay targeting the matrix gene and more specifically as pigeon paramyxovirus serotype 1 (PPMV-1) by hemagglutinin inhibition with monoclonal antibodies. Based upon partial genomic sequencing and phylogenetic analysis, the newly isolated viruses represent a distinct sublineage within class II genotype VIb. All of the viruses (15/15) were classified as virulent based upon their fusion cleavage site motif (112RRKKRF117) and intracerebral pathogenicity indices of >0.7 (ranging from 0.98 to1.35); however, these viruses escaped detection by the fusion gene-based real-time PCR test for virulence. Modifications introduced to the probe site of the fusion gene-based assay allowed rapid virulence detection within this distinct sublineage. PMID:18716227

  8. The provision of on street passenger information via real time passenger information; a case study of Dublin

    OpenAIRE

    Caulfield, Brian; O'MAHONY, MARGARET MARY

    2004-01-01

    PUBLISHED In June 2001 Dublin Bus introduced a real time passenger information (RTPI) system on the first of its eleven quality bus corridors (QBC), on the Lucan QBC. The introduction is part of a three-year pilot programme called 'Q-time', which was established to test RTPI on three QBCs before deciding on the roll out of the system across the Dublin Bus network. This system displays, passenger information with regard to the estimated wait time on passenger information displays at bus sto...

  9. The usability of passenger delay models in socio-economic analysis

    DEFF Research Database (Denmark)

    Thorhauge, Mikkel

    The following paper discusses how a passenger delay model can be used in socio-economic calculations. At present passenger delays are often omitted in the modeling phase and therefore not included in the analysis. By using a passenger delay model passenger delays can be included in a cost......-benefit analysis. Including passenger delays in the cost-benefit analysis will increase the level of details and thereby improve the accuracy of socio-economic analysis. In this paper the third generation passenger delay model is used. This model is the newest and most detailed passenger delay model created so far....... The main problem when including passenger delays is to determine the value of time for passenger delays and how to include the delays in a socio-economic analysis. This is due to the fact that passenger delays are not defined unambiguously. In general, delays can occur on different parts of a journey...

  10. Development of Extinction Imagers for the Determination of Atmospheric Optical Extinction

    Science.gov (United States)

    2014-08-01

    extinction coefficient > 0.4 km" ), the transmissometer tends to report higher values than the MSI. There are two possible reasons for this behavior ...REPORT TYPE Final Report 4. TITLE AND SUBTITLE Development of Extinction Imagers for the Determination of Atmospheric Optical Extinction 6. AUTHOR...further develop Extinction Imagers for use in the ocean environment, and to extend the capabilities into the Short Wave IR (SWIR). Extinction Imaging

  11. Safety on Passenger Ferries from Catering Crew's Perspective

    National Research Council Canada - National Science Library

    Ljung, M; Oudhuis, Margareata

    2016-01-01

    ... staff’s experiences and perceptions of safety practice on board passenger ferries. The methods are semi-structured interviews and a qualitative content analysis of official documents and research articles. Results...

  12. Some issues of passenger choice of suburban transport mode

    Directory of Open Access Journals (Sweden)

    Тetyana М. Grigorova

    2015-06-01

    Full Text Available In this article the passenger choice of transport mode for moving to suburban is discussed. The analysis of methods of Transport Management in suburban transportation showed that they did not fully take into account the effect of the transport process parameters on the passenger choice of transport mode for travel. The aim of research is to determine the value of the factors that influence passenger choice of suburban transport. The study was conducted on the basis of passenger survey on the factors affecting the choice of transport mode, and the importance of these factors. Kendall's coefficient of concordance its statistical significance were used to evaluate the consistency of expert opinion. The main factors for choosing the mode of suburban transport are identified. The identified factors can then be used in determining selection patterns of suburban transport mode.

  13. Just-in-Time Information Delivery System for Passenger Assistance

    National Research Council Canada - National Science Library

    NOZUE, Michiko; OZAKI, Naoya; TSUCHIYA, Ryuji

    2006-01-01

    ... and integrate them to make their travel decisions. We first provide a brief overview of an intermodal passenger support system called "CyberGuide," then propose an intelligent and just-in-time information retrieval agent that takes into consideration...

  14. Violence Against Drivers and Conductors in the Road Passenger ...

    African Journals Online (AJOL)

    Test

    increased likelihood of exposure to workplace violence in the road passenger transport ..... content and administration; understanding ethical issues, such as respect for privacy while .... Statistical significance was assumed at a p-value < 0.05.

  15. Fuzzy Temporal Logic Based Railway Passenger Flow Forecast Model

    Science.gov (United States)

    Dou, Fei; Jia, Limin; Wang, Li; Xu, Jie; Huang, Yakun

    2014-01-01

    Passenger flow forecast is of essential importance to the organization of railway transportation and is one of the most important basics for the decision-making on transportation pattern and train operation planning. Passenger flow of high-speed railway features the quasi-periodic variations in a short time and complex nonlinear fluctuation because of existence of many influencing factors. In this study, a fuzzy temporal logic based passenger flow forecast model (FTLPFFM) is presented based on fuzzy logic relationship recognition techniques that predicts the short-term passenger flow for high-speed railway, and the forecast accuracy is also significantly improved. An applied case that uses the real-world data illustrates the precision and accuracy of FTLPFFM. For this applied case, the proposed model performs better than the k-nearest neighbor (KNN) and autoregressive integrated moving average (ARIMA) models. PMID:25431586

  16. Fuzzy temporal logic based railway passenger flow forecast model.

    Science.gov (United States)

    Dou, Fei; Jia, Limin; Wang, Li; Xu, Jie; Huang, Yakun

    2014-01-01

    Passenger flow forecast is of essential importance to the organization of railway transportation and is one of the most important basics for the decision-making on transportation pattern and train operation planning. Passenger flow of high-speed railway features the quasi-periodic variations in a short time and complex nonlinear fluctuation because of existence of many influencing factors. In this study, a fuzzy temporal logic based passenger flow forecast model (FTLPFFM) is presented based on fuzzy logic relationship recognition techniques that predicts the short-term passenger flow for high-speed railway, and the forecast accuracy is also significantly improved. An applied case that uses the real-world data illustrates the precision and accuracy of FTLPFFM. For this applied case, the proposed model performs better than the k-nearest neighbor (KNN) and autoregressive integrated moving average (ARIMA) models.

  17. Environmental Performance Evaluation of Ro-Ro Passenger Ferry Transportation

    DEFF Research Database (Denmark)

    Kristensen, Hans Otto Holmegaard; Hagemeister, Constantin

    2012-01-01

    With increasing focus on the environmental performance of different transport modes (for example trucks, trains, ships and aircraft) it is of utmost importance that the different transport modes are compared on an equal basis so that the environmental impact, defined as energy demand and....../or emissions per transport unit, is related to the same unit for the different transport forms. For Ro-Ro passenger ferries it can be difficult to find a suitable common transport unit, as they often transport a mix of cargo, such as passengers, passenger cars, trucks, lorries, busses and other rolling...... transport units. In this paper a method for determination of a common transport unit for Ro-Ro passenger ships will be described....

  18. Equilibrium analysis of mixed passengers in urban railway network

    Institute of Scientific and Technical Information of China (English)

    张璐; 吴建军; 孙会君

    2016-01-01

    A model is proposed to describe the passengers’ route choice behaviors in urban railway traffic with stochastic link capacity degradation by considering two types of demand, sensitive and insensitive passenger. The insensitive passengers choose their route without paying much attention to congestion. To the contrary, sensitive passengers who consider route congestion choose travel route based on generalized cost. An equilibrium state is given by variational inequalities in terms of travel generalized cost, which is represented by the combinations of mean and variance of total travel time. The diagonalization algorithm is given to solve this programming. Results show that insensitive passengers have large effects on the path choice than sensitive ones, especially for the larger demand.

  19. Bus Passenger Recognition and Track of Video Sequence

    Directory of Open Access Journals (Sweden)

    Donghua Zhou

    2013-06-01

    Full Text Available Study on bus passenger recognition and track of video sequence is a research aiming at realizing making a statistics on passenger flow volume of bus, which not only helps traffic services center rationally schedule vehicles, but also can avoid overload. The system makes machine vision technology and digital image processing technique applied in customer counting of bus. The key questions in the study include effective collection of video image, effective extraction of moving object in sequence images, recognition of moving targets, trace and count of moving objects. The paper makes deep analysis on relevant technology from the perspective of the theory and practical application of the algorithm, and the study makes achievements. The theoretical algorithm for the study on bus passenger recognition and track of video sequence is distinctive. The practical experiments indicate that the system can satisfy the real-time requirements, and can accurately make statistics on the number of passengers, which has great application value.

  20. Complete transection of the trunk of passengers in car accidents.

    Science.gov (United States)

    Nadjem, H; Ropohl, D

    1996-06-01

    Traumatic amputation of extremities and complete severance of the trunk have been reported in extra-urban collisions between passenger cars and pedestrians at collision speeds of > 80-100 km/h (50-62 mi/h). In car passengers, such extreme types of injuries are very rare. Two cases are presented in which the cars had a lateral collision with road trees near the right B column (column between front and back door), as a result of which the car was torn into two parts just in front of the rear axle near the back seats. Under these circumstances, the trunk of the back passenger on the side of the collision was completely severed. Both accidents happened in left-hand bends and the speed of collisions amounted to 120 and 180 km/h (74 and 111 mi/h), respectively. All passengers were flung out of the cars.

  1. Antioxidation, angiotensin converting enzyme inhibition activity, nattokinase, and antihypertension of Bacillus subtilis (natto-fermented pigeon pea

    Directory of Open Access Journals (Sweden)

    Bao-Hong Lee

    2015-12-01

    Full Text Available Because of the high incidence of cardiovascular diseases in Asian countries, traditional fermented foods from Asia have been increasingly investigated for antiatherosclerotic effects. This study investigated the production of nattokinase, a serine fibrinolytic enzyme, in pigeon pea by Bacillus subtilis fermentation. B. subtilis 14714, B. subtilis 14715, B. subtilis 14716, and B. subtilis 14718 were employed to produce nattokinase. The highest nattokinase activity in pigeon pea was obtained using B. subtilis 14715 fermentation for 32 hours. In addition, the levels of antioxidants (phenolics and flavonoids and angiotensin converting enzyme inhibitory activity were increased in B. subtilis 14715-fermented pigeon pea, compared with those in nonfermented pigeon pea. In an animal model, we found that both water extracts of pigeon pea (100 mg/kg body weight and water extracts of B. subtilis-fermented pigeon pea (100 mg/kg body weight significantly improved systolic blood pressure (21 mmHg and diastolic blood pressure (30 mmHg in spontaneously hypertensive rats. These results suggest that Bacillus-fermented pigeon pea has benefits for cardiovascular health and can be developed as a new dietary supplement or functional food that prevents hypertension.

  2. Antioxidation, angiotensin converting enzyme inhibition activity, nattokinase, and antihypertension of Bacillus subtilis (natto)-fermented pigeon pea.

    Science.gov (United States)

    Lee, Bao-Hong; Lai, Yi-Syuan; Wu, She-Ching

    2015-12-01

    Because of the high incidence of cardiovascular diseases in Asian countries, traditional fermented foods from Asia have been increasingly investigated for antiatherosclerotic effects. This study investigated the production of nattokinase, a serine fibrinolytic enzyme, in pigeon pea by Bacillus subtilis fermentation. B. subtilis 14714, B. subtilis 14715, B. subtilis 14716, and B. subtilis 14718 were employed to produce nattokinase. The highest nattokinase activity in pigeon pea was obtained using B. subtilis 14715 fermentation for 32 hours. In addition, the levels of antioxidants (phenolics and flavonoids) and angiotensin converting enzyme inhibitory activity were increased in B. subtilis 14715-fermented pigeon pea, compared with those in nonfermented pigeon pea. In an animal model, we found that both water extracts of pigeon pea (100 mg/kg body weight) and water extracts of B. subtilis-fermented pigeon pea (100 mg/kg body weight) significantly improved systolic blood pressure (21 mmHg) and diastolic blood pressure (30 mmHg) in spontaneously hypertensive rats. These results suggest that Bacillus-fermented pigeon pea has benefits for cardiovascular health and can be developed as a new dietary supplement or functional food that prevents hypertension. Copyright © 2015. Published by Elsevier B.V.

  3. Chlamydia psittaci genotype B in a pigeon (Columba livia) inhabiting a public place in San José, Costa Rica.

    Science.gov (United States)

    Dolz, G; Solórzano-Morales, Á; Angelova, L; Tien, C; Fonseca, L; Bonilla, M C

    2013-01-01

    Human chlamydiosis is a zoonotic disease of avian origin caused by Chlamydia psittaci. The highest infection rates have been detected in parrots (Psittacidae) and pigeons (Columbiformes), the latter most frequently carry the genotypes B and E. These genotypes have been shown to also infect humans. Because pigeons (Columba livia) cohabit with humans in urban areas, C. psittaci present in the dust from dry feces of infected pigeons may be transmitted by inhalation and represent a significant public health problem. Between 2012 and 2013 a total of 120 fecal samples were collected from pigeons at four public places (Plaza de la Cultura, Parque Morazán, Parque Central de Guadalupe, Plaza de las Garantías Sociales) in San José, Costa Rica. A nested polymerase chain reaction (PCR) was used to amplify a region of the outer membrane protein A gene of C. psittaci. Only one sample was positive in PCR and the positive sample was further subjected to sequencing and genotyping. Sequencing identified this sample as C. psittaci genotype B. This study is the first report to show the presence of this organism in pigeons of Costa Rica, and shows that the infected pigeons may represent a significant risk for humans who visit public places that are inhabited by pigeons.

  4. Chlamydia psittaci genotype B in a pigeon (Columba livia inhabiting a public place in San José, Costa Rica

    Directory of Open Access Journals (Sweden)

    G. Dolz

    2013-12-01

    Full Text Available Human chlamydiosis is a zoonotic disease of avian origin caused by Chlamydia psittaci. The highest infection rates have been detected in parrots (Psittacidae and pigeons (Columbiformes, the latter most frequently carry the genotypes B and E. These genotypes have been shown to also infect humans. Because pigeons (Columba livia cohabit with humans in urban areas, C. psittaci present in the dust from dry feces of infected pigeons may be transmitted by inhalation and represent a significant public health problem. Between 2012 and 2013 a total of 120 fecal samples were collected from pigeons at four public places (Plaza de la Cultura, Parque Morazán, Parque Central de Guadalupe, Plaza de las Garantías Sociales in San José, Costa Rica. A nested polymerase chain reaction (PCR was used to amplify a region of the outer membrane protein A gene of C. psittaci. Only one sample was positive in PCR and the positive sample was further subjected to sequencing and genotyping. Sequencing identified this sample as C. psittaci genotype B. This study is the first report to show the presence of this organism in pigeons of Costa Rica, and shows that the infected pigeons may represent a significant risk for humans who visit public places that are inhabited by pigeons.

  5. Prevalence and Pathology of Trichomoniasis in Free AND#8211; Living Urban Pigeons in the City of Mosul, Iraq

    Directory of Open Access Journals (Sweden)

    Hafidh I. Al- Sadi and Aws Z. Hamodi

    2011-02-01

    Full Text Available The present study was undertaken to determine the prevalence of trichomoniasis and its pathology in pigeons. A total of 100 free living urban pigeons were collected during the months August and September 2007. The overall prevalence was 16%. In infected pigeons, yellowish – white masses of caseous necrotic material were seen grossly in the oral cavity, esophagus, crop, and proventiculus. Pale to yellow necrotic areas were noted in the liver. Multiple foci of caseous necrosis were seen microscopically in the oral mucosa together with heavy infiltration of inflammatory cells (mainly heterophils. Foci of necrotic inflammation were seen in the liver and there was thickening of the lining mucosa of the esophagus due to extensive infiltration of heterophils. Collections of necrotic material were seen in the mucosa and submucosa of the esophagus. Infection occurred more frequently in young than in adult pigeons. A higher prevalence of the infection was noted in male than in female pigeons. In all of the infected pigeons, trichomoniasis occured in the absence of apparent secondary disease. It was concluded that trichomonad infection is fairly common in free living urban pigeons in the city of Mosul, Iraq. [Veterinary World 2011; 4(1.000: 12-14

  6. Neanderthal extinction by competitive exclusion.

    Directory of Open Access Journals (Sweden)

    William E Banks

    Full Text Available BACKGROUND: Despite a long history of investigation, considerable debate revolves around whether Neanderthals became extinct because of climate change or competition with anatomically modern humans (AMH. METHODOLOGY/PRINCIPAL FINDINGS: We apply a new methodology integrating archaeological and chronological data with high-resolution paleoclimatic simulations to define eco-cultural niches associated with Neanderthal and AMH adaptive systems during alternating cold and mild phases of Marine Isotope Stage 3. Our results indicate that Neanderthals and AMH exploited similar niches, and may have continued to do so in the absence of contact. CONCLUSIONS/SIGNIFICANCE: The southerly contraction of Neanderthal range in southwestern Europe during Greenland Interstadial 8 was not due to climate change or a change in adaptation, but rather concurrent AMH geographic expansion appears to have produced competition that led to Neanderthal extinction.

  7. Exploring co-extinction correlates

    DEFF Research Database (Denmark)

    Carpaneto, Giuseppe Maria; Mazziotta, Adriano; Pittino, Riccardo

    2011-01-01

    Co-extinction is a recurring topic in conservation biology. Quantification of co-extinction has been generally restricted to parasite-host, predator-prey and herbivore-host plant interactions. The loss of detritivorous insects upon the depletion of herbivore mammals has been poorly explored. Here...... of scarab beetle communities. Rarefaction curves estimated that a 50% reduction in the number of sample units where squirrel faecal pellets are the only available food resource accounts for a reduction of 28% of all the scarab species, and of 24% of the squirrel-linked species. The current decline of ground...... that the conservation of ground squirrels and their affiliate scarab species may be ensured by a moderate livestock grazing, owing to the higher ecological success of these rodents in the presence of large herbivores keeping low the grass cover. © 2011 Springer Science+Business Media B.V....

  8. Epidemiological survey of zoonotic pathogens in feral pigeons (Columba livia var. domestica) and sympatric zoo species in Southern Spain.

    Science.gov (United States)

    Cano-Terriza, David; Guerra, Rafael; Lecollinet, Sylvie; Cerdà-Cuéllar, Marta; Cabezón, Oscar; Almería, Sonia; García-Bocanegra, Ignacio

    2015-12-01

    A cross-sectional study was carried out to determine the prevalence of pathogenic zoonotic agents (flaviviruses, avian influenza viruses (AIVs), Salmonella spp. and Toxoplasma gondii) in feral pigeons and sympatric zoo animals from Córdoba (Southern Spain) between 2013 and 2014. Antibodies against flaviviruses were detected in 7.8% out of 142 (CI95%: 3.7-11.8) pigeons, and 8.2% of 49 (CI95%: 0.9-15.4) of zoo animals tested. Antibodies with specificity against West Nile virus (WNV) and Usutu virus (USUV) were confirmed both in pigeons and in zoo birds. Even though seropositivity to AIVs was not detected in any of the analyzed pigeons, 17.9% of 28 (CI95%: 3.7-32.0) zoo birds tested showed positive results. Salmonella spp. was not isolated in any of 152 fecal samples collected from pigeons, while 6.8% of 44 zoo animals were positive. Antibodies against T. gondii were found in 9.2% of 142 (CI95%: 4.8-13.6) feral pigeons and 26.9% of 108 (CI95%: 19.6-34.1) zoo animals. This is the first study on flaviviruses and T. gondii in feral pigeons and captive zoo species in Spain. Antibodies against WNV and USUV detected in non-migratory pigeons and captive zoo animals indicate local circulation of these emerging pathogens in the study area. T. gondii was widespread in species analyzed. This finding could be of importance for Public Health and Conservation of endangered species present in zoo parks. Pigeons and zoo animals may be included as sentinel species for monitoring zoonotic pathogens in urban areas.

  9. Combustion characteristics of coal and refuse from passenger trains.

    Science.gov (United States)

    Fu-min, Ren; Feng, Yue; Ming, Gao; Min, Yu

    2010-07-01

    Refuse from passenger trains is becoming a significant issue with the development of the Chinese railway. Co-firing is regarded as a promising thermal technology, both environmentally and economically, in reducing the quantity of refuse. The co-firing property of passenger train refuse with coal, however, may differ due to the differences in the composition of the refuse. In the present study, combustion properties of refuse from passenger train samples and the mixture of refuse with coal were studied in a tube furnace. Thermo analysis methods, such as thermogravimetry (TG), differential scanning calorimetry (DSC), differential thermal analysis (DTA) and derivative thermogravimetry (DTG) analyses were employed to evaluate combustion performance. We found that the mixture of passenger train refuse and coal at a ratio of 1:1 has a lower ignition and burnout temperature than the coal-only sample. Moreover, refuse from railway passenger trains has more reactive combustion properties than the coal-only sample, and the addition of railway passenger train refuse to coal can promote the reactivity of coal.

  10. Natural infections with Pigeon Paramyxovirus-1: Pathologic changes in Eurasian collared-doves (Streptopelia decaocto) and rock pigeons (Columba livia) in the USA: Data

    Science.gov (United States)

    Isidoro-Ayza, Marcos; Lankton, Julia S.; Knowles, Susan N.; Ip, Hon S.; White, C. LeAnn

    2017-01-01

    We reviewed pathological findings and to a lesser extent epidemiological data from 70 free-ranging columbiforms naturally infected with Pigeon paramyxovirus-1 (PPMV-1) from 25 different PPMV-1 mortality events in columbiforms in the USA. In a subset of 17 birds from 10 of the studied outbreaks, we carried out immunohistochemistry targeting PPMV-1 nucleoprotein to determine the tissue distribution of the virus.

  11. Types of solutions improving passenger transport interconnectivity

    Directory of Open Access Journals (Sweden)

    Monika BĄK

    2012-01-01

    Full Text Available The objective of the paper is to present different types of solutions which could improve interconnectivity of passenger transport especially within interconnections between long and short transport distance. The topic has particular relevance at the European level because the European transport networks’ role as integrated international networks is compromised by poor interconnectivity and because the next generation of European transport policies will have to be sensitive to the differences between short, medium and long-term transport markets and the market advantages of each transport mode. In this context, a realistic assessment of intermodal opportunities is a key ingredient to future policy development.Effective interconnection requires the provision of integrated networks and services which are attractive to potential users and this is likely to require co-operation between a range of authorities and providers in the public and private sectors and may necessitate a wider vision than might otherwise prevail.The paper is based on the results of the project realised by the team of the University of Gdansk in the EU funded 7 Framework Programme - INTERCONNECT (Interconnection between short- and long-distance transport networks with partners in the UK, Germany, Denmark, Poland, Spain and Italy. Different types of solutions will be summarized in the paper including e.g. local link infrastructure solutions, improved local public transport services, improvements at the interchange, solutions involving improved procedures for check-in or luggage transfer & documentation, pricing and ticketing solutions, solutions involving marketing, information and sales.

  12. Energy Chain Analysis of Passenger Car Transport

    Directory of Open Access Journals (Sweden)

    Hans Jakob Walnum

    2011-02-01

    Full Text Available Transport makes up 20 percent of the World’s energy use; in OECD countries this has exceeded 30 percent. The International Energy Agency (IEA estimates that the global energy consumption will increase by 2.1 percent annually, a growth rate that is higher than for any other sector. The high energy consumption means that transportation accounts for nearly 30 percent of CO2 emission in OECD countries and is also one of the main sources of regional and local air pollution. In this article, we analyze energy consumption and greenhouse gas emissions from passenger car transport using an energy chain analysis. The energy chain analysis consists of three parts: the net direct energy use, the energy required for vehicle propulsion; the gross direct chain, which includes the net direct energy consumption plus the energy required to produce it; and, finally, the indirect energy chain, which includes the energy consumption for production, maintenance and operation of infrastructure plus manufacturing of the vehicle itself. In addition to energy consumption, we also analyze emissions of greenhouse gases measured by CO2-equivalents. We look at the trade-offs between energy use and greenhouse gas emissions to see whether some drivetrains and fuels perform favourable on both indicators. Except for the case of electric cars, where hydropower is the only energy source in the Norwegian context, no single car scores favourably on both energy consumption and greenhouse gas emissions.

  13. Cavity Attenuated Phase Shift (CAPS) Method for Airborne Aerosol Light Extinction Measurement: Instrument Validation and First Results from Field Deployment

    Science.gov (United States)

    Petzold, A.; Perim de Faria, J.; Berg, M.; Bundke, U.; Freedman, A.

    2015-12-01

    Monitoring the direct impact of aerosol particles on climate requires the continuous measurement of aerosol optical parameters like the aerosol extinction coefficient on a regular basis. Remote sensing and ground-based networks are well in place (e.g., AERONET, ACTRIS), whereas the regular in situ measurement of vertical profiles of atmospheric aerosol optical properties remains still an important challenge in quantifying climate change. The European Research Infrastructure IAGOS (In-service Aircraft for a Global Observing System; www.iagos.org) responds to the increasing requests for long-term, routine in situ observational data by using commercial passenger aircraft as measurement platform. However, scientific instrumentation for the measurement of atmospheric constituents requires major modifications before being deployable aboard in-service passenger aircraft. Recently, a compact and robust family of optical instruments based on the cavity attenuated phase shift (CAPS) technique has become available for measuring aerosol light extinction. While this technique was successfully deployed for ground-based atmospheric measurements under various conditions, its suitability for operation aboard aircraft in the free and upper free troposphere still has to be demonstrated. In this work, the modifications of a CAPS PMex instrument for measuring aerosol light extinction on aircraft, the results from subsequent laboratory tests for evaluating the modified instrument prototype, and first results from a field deployment aboard a research aircraft will be covered. In laboratory studies, the instrument showed excellent agreement (deviation < 5%) with theoretical values calculated from Rayleigh scattering cross-sections, when operated on pressurized air and CO2 at ambient and low pressure (~200 hPa). For monodisperse and polydisperse aerosols, reference aerosol extinction coefficients were calculated from measured size distributions and agreed with the CAPS PMex instrument

  14. Detection of Chlamydophila psittaci from pigeons by polymerase chain reaction in Ahvaz

    Directory of Open Access Journals (Sweden)

    Masoud Ghorbanpoor

    2015-10-01

    Full Text Available Background and Objective: Chlamydophila psittaci is a lethal bacterium that causes endemic avian chlamydiosis, and respiratory psittacosis. Laboratory diagnosis of Chlamydophila psittaci is difficult by culture. This study was design to investigate the presence of Chlamydophila psittaci in collected pharyngeal swabs from asyptomatic pigeons by PCR.Materials and Methods: Pharyngeal samples from pigeons with no symptoms of disease (n=280 were collected during hot and cold seasons in different parts of Ahvaz. DNA was extracted from specimens and subjected to PCR targeting pmp genes and 16s-23s rRNA intergenic spacer of Cp. psittaci and chlamydiales specific primers.Results: Of 280 samples 2 (0.7% harbor were positive for chlamydiales (16s-23s intergenic spacer and Cp. psittaci specific genes (pmp gene.Conclusions: In this research the pigeons were asymptomatic carriers for Cp. psittaci in their respiratory discharges. These results suggest that Cp. psittaci infection of human can occur in very close and continuous contact with pigeons.

  15. Depth to Transition--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the depth-to-transition map of the Pigeon Point to South Monterey Bay, California, region. The raster data file is included in...

  16. Utilization of Decorticated Pigeon Pea (Cajanus cajan L. With Wheat (Triticum aestivum Flours in Bread Making

    Directory of Open Access Journals (Sweden)

    H.A. Hassan

    2011-12-01

    Full Text Available The objectives of this study were to investigate the use of decorticated pigeon pea flour in the development of protein rich - bread, suitable for general and specific nutritional purposes and to study the effect of incorporation of pigeon pea flour on the sensory evaluation and quality of bread produced. Decorticated Pigeon Pea Flour (DPPF was incorporated with wheat flour (WF 72% Ext. to replace 0, 5, 10, 15, 20 and 25% of the wheat flour for bread making. Proximate composition, falling number, gluten quality and quantity, tannins and phytic acid were determined for the flour blends (Composite flour. Bread proximate composition, sensory evaluation and specific volume were determined as well. Decortication of pigeon pea led to decrease in moisture, ash, tannins and phytic acid and increase in the protein and carbohydrates contents. The falling number (alpha amylase activity significantly increased over the control with the increasing level of DPPF. There were also significant reduction (p#0.05 on gluten quantity (wet and dry gluten and quality (gluten index. No significant differences were found in bread specific volume up to 10% addition of DPPF. The protein, ash, fat contents and calorific values for the bread were significantly increased (p#0.05 with incorporation of DPPF. Increasing levels of the replacement of DPPF resulted in a decrease in the organoleptic quality of the bread. The bread containing up to 15% DPPF was found to be the best in overall acceptability.

  17. Age-Dependent Neurogenesis and Neuron Numbers within the Olfactory Bulb and Hippocampus of Homing Pigeons

    Science.gov (United States)

    Meskenaite, Virginia; Krackow, Sven; Lipp, Hans-Peter

    2016-01-01

    Many birds are supreme long-distance navigators that develop their navigational ability in the first months after fledgling but update the memorized environmental information needed for navigation also later in life. We studied the extent of juvenile and adult neurogenesis that could provide such age-related plasticity in brain regions known to mediate different mechanisms of pigeon homing: the olfactory bulb (OB), and the triangular area of the hippocampal formation (HP tr). Newly generated neurons (visualized by doublecortin, DCX) and mature neurons were counted stereologically in 35 pigeon brains ranging from 1 to 168 months of age. At the age of 1 month, both areas showed maximal proportions of DCX positive neurons, which rapidly declined during the first year of life. In the OB, the number of DCX-positive periglomerular neurons declined further over time, but the number of mature periglomerular cells appeared unchanged. In the hippocampus, the proportion of DCX-positive neurons showed a similar decline yet to a lesser extent. Remarkably, in the triangular area of the hippocampus, the oldest birds showed nearly twice the number of neurons as compared to young adult pigeons, suggesting that adult born neurons in these regions expanded the local circuitry even in aged birds. This increase might reflect navigational experience and, possibly, expanded spatial memory. On the other hand, the decrease of juvenile neurons in the aging OB without adding new circuitry might be related to the improved attachment to the loft characterizing adult and old pigeons. PMID:27445724

  18. Cultivar preference and sensory evaluation of vegetable pigeon pea (Cajanus cajan) in Eastern Kenya

    Science.gov (United States)

    Preference and acceptability of twelve vegetable pigeon pea genotypes of medium maturity was evaluated in Eastern Kenya based on six seed cultivar parameters of color, appearance, taste, odor, tenderness and overall seed acceptability. The sensory characteristics were scored by consumers and farmers...

  19. A family with extrinsic allergic alveolitis caused by wild city pigeons: A case report

    NARCIS (Netherlands)

    G.J. du Marchie Sarvaas; P.J.F.M. Merkus (Peter); J.C. de Jongste (Johan)

    2000-01-01

    textabstractWe describe a family in which the mother died of unresolved lung disease and whose 5 children, some of whom had previous signs of asthma, were subsequently affected by extrinsic allergic alveolitis caused by contact with wild city pigeon antigens. The children received

  20. Discrimination of complex human behavior by pigeons (Columba livia and humans.

    Directory of Open Access Journals (Sweden)

    Muhammad A J Qadri

    Full Text Available The cognitive and neural mechanisms for recognizing and categorizing behavior are not well understood in non-human animals. In the current experiments, pigeons and humans learned to categorize two non-repeating, complex human behaviors ("martial arts" vs. "Indian dance". Using multiple video exemplars of a digital human model, pigeons discriminated these behaviors in a go/no-go task and humans in a choice task. Experiment 1 found that pigeons already experienced with discriminating the locomotive actions of digital animals acquired the discrimination more rapidly when action information was available than when only pose information was available. Experiments 2 and 3 found this same dynamic superiority effect with naïve pigeons and human participants. Both species used the same combination of immediately available static pose information and more slowly perceived dynamic action cues to discriminate the behavioral categories. Theories based on generalized visual mechanisms, as opposed to embodied, species-specific action networks, offer a parsimonious account of how these different animals recognize behavior across and within species.

  1. Sub-Optimal Choice by Pigeons: Failure to Support the Allais Paradox

    Science.gov (United States)

    Zentall, Thomas R.; Stagner, Jessica P.

    2011-01-01

    Pigeons show a preference for an alternative that provides them with discriminative stimuli (sometimes a stimulus that predicts reinforcement and at other times a stimulus that predicts the absence of reinforcement) over an alternative that provides them with nondiscriminative stimuli, even if the nondiscriminative stimulus alternative is…

  2. Fast- and slow-exploring pigeons differ in how they use previously learned rules.

    Science.gov (United States)

    Guillette, L M; Baron, D M; Sturdy, C B; Spetch, M L

    2017-01-01

    Several studies report a correlation between exploratory behaviour and performance on tests of cognitive ability. Exploration may influence learning because less exploratory animals are less likely to come in contact with to-be-learned stimuli. Alternatively, the way information available in the environment is processed could influence the rate of exploration. Pigeons are one of the most-studied species used to examine the mechanisms underlying cognitive abilities, but have not been used to examine the relationship between these abilities and animal personality. Here, twelve pigeons were first tested in a novel environment to assess repeatability in exploratory behaviour. Pigeons were then trained to discriminate between two visual stimuli: lines oriented at 90° (vertical, the S+) and 135° (the S-). After training pigeons underwent generalization testing with ten additional visual line orientation stimuli. We found exploratory behaviour was related to generalization performance: fast-explorers had steeper generalization gradients compared to slow-explorers. This effect was only seen in the direction towards the S-. These results suggest that birds with different exploratory styles differ in how they use previously learned information. Further testing is needed to confirm which cue(s) (S+ or S-) control the behaviour of fast-explorers. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Effects of Pre-Trial Response Requirements on Self-Control Choices by Rats and Pigeons

    Science.gov (United States)

    Mazur, James E.

    2012-01-01

    Parallel experiments with rats and pigeons examined whether the size of a pre-trial ratio requirement would affect choices in a self-control situation. In different conditions, either 1 response or 40 responses were required before each trial. In the first half of each experiment, an adjusting-ratio schedule was used, in which subjects could…

  4. Following the sun: a mathematical analysis of the tracks of clock-shifted homing pigeons.

    Science.gov (United States)

    Schiffner, Ingo; Siegmund, Bettina; Wiltschko, Roswitha

    2014-08-01

    We analysed the tracks of clock-shifted pigeons from six releases to determine how they cope with the conflict between their sun compass and other navigational cues. Time-lag embedding was used to calculate the short-term correlation dimension, a parameter that reflects the complexity of the navigational system, and with it, the number of factors involved. Initially, while pigeons were still at the release site, the short-term correlation dimension was low; it increased as the birds left the site, indicating that the birds were now actively navigating. Clock-shifted pigeons showed more scatter than the control birds, and their short-term correlation dimension became significantly smaller than that of the controls, remaining lower until the experimental birds reached their loft. This difference was small, but consistent, and suggests a different rating and ranking of the navigational cues. Clock-shifted pigeons do not seem to simply ignore the information from their manipulated sun compass altogether, but appear to merely downgrade it in favour of other cues, like their magnetic compass. This is supported by the observation that the final part of the tracks still showed a small deviation in the expected direction, indicating an effect of clock-shifting until the end of the homing flight.

  5. Model validation through long-term promising sustainable maize/pigeon pea residue management in Malawi

    NARCIS (Netherlands)

    Mwale, C.D.; Kabambe, V.H.; Sakale, W.D.; Giller, K.E.; Kauwa, A.A.; Ligowe, I.; Kamalongo, D.

    2013-01-01

    In the 2005/2006 season, the Model Validation Through Long-Term Promising Sustainable Maize/Pigeon Pea Residue Management experiment was in the 11th year at Chitedze and Chitala, and in the 8th year at Makoka and Zombwe. The experiment was a split-plot design with cropping system as the main plot an

  6. Characterization of Newcastle disease virus isolates recovered from pigeons in the territory of the Russian Federation

    Science.gov (United States)

    Newcastle disease (ND) is a continual problem for the poultry industry with synanthropic birds representing one of the possible reservoirs of infection. Outbreaks of ND are regularly confirmed among pigeons in different regions of the Russian Federation. The spread of Newcastle disease virus (NDV) a...

  7. Effects of avermectin on immune function and oxidative stress in the pigeon spleen.

    Science.gov (United States)

    Liu, Ci; Li, Ming; Cao, Ye; Qu, Jian-Ping; Zhang, Zi-Wei; Xu, Shi-Wen; Li, Shu

    2014-03-05

    Avermectin (AVM) is a pesticide that can accumulate in the environment through spray-drift, runoff or field drainage. Residues of AVM or its metabolites in livestock feces have toxic effects on non-target aquatic and terrestrial organisms. In this study, changes in oxidative stress and immunity in pigeon spleen tissues were detected after subchronic exposure to AVM for 30, 60, and 90 days. In pigeon spleen, the activities of total anti-oxidation capability (T-AOC), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) decreased significantly, whereas the levels of malondialdehyde (MDA), protein carbonyl (PCO), and DNA-protein crosslink (DPC) coefficients increased. Additionally, obvious ultrastructure alterations were observed. These results indicated that AVM induced oxidative stress and damaged the normal structure of spleen cells. The exposure to AVM could lead to increases in the mRNA levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and interleukin-4 (IL-4), as well as a decrease in the mRNA level of interferon-γ (IFN-γ), in a dose-time-dependent manner in pigeon spleen. The results imply that AVM induces immunosuppression in the spleen tissue of pigeons. The information presented in this study may be helpful for understanding the mechanism of AVM-induced immunotoxicity in birds.

  8. Characterization of five fungal endophytes producing Cajaninstilbene acid isolated from pigeon pea [Cajanus cajan (L. Millsp].

    Directory of Open Access Journals (Sweden)

    Yuan Gao

    Full Text Available Five fungal endophytes (K4, K5, K6, K9, K14 producing Cajaninstilbene acid (CSA, 3-hydroxy-4-prenyl-5-methoxystilbene-2-carboxylic acid were isolated from the roots of pigeon pea [Cajanus cajan (L. Millsp.]. CSA is responsible for the prominent pharmacological activities in pigeon pea. The amount of CSA in culture solution varied among the five fungal endophytes. K4 produced the highest levels of CSA (1037.13 µg/L among the endophytes tested after incubation for five days. Both morphological characteristics and molecular methods were used for species identification of fungal endophytes. The five endophytic isolates were characterized by analyzing the internal transcribed spacer (ITS rRNA and β-tubulin genes. The K4, K5, K9 and K14 strains isolated from pigeon pea roots were found to be closely related to the species Fusarium oxysporum. K6 was identified as Neonectria macrodidym. The present study is the first report on the isolation and identification of fungal endophytes producing CSA in pigeon pea. The study also provides a scientific base for large scale production of CSA.

  9. A Kinect-based system for automatic recording of some pigeon behaviors.

    Science.gov (United States)

    Lyons, Damian M; MacDonall, James S; Cunningham, Kelly M

    2015-12-01

    Contact switches and touch screens are the state of the art for recording pigeons' pecking behavior. Recording other behavior, however, requires a different sensor for each behavior, and some behaviors cannot easily be recorded. We present a flexible and inexpensive image-based approach to detecting and counting pigeon behaviors that is based on the Kinect sensor from Microsoft. Although the system is as easy to set up and use as the standard approaches, it is more flexible because it can record behaviors in addition to key pecking. In this article, we show how both the fast, fine motion of key pecking and the gross body activity of feeding can be measured. Five pigeons were trained to peck at a lighted contact switch, a pigeon key, to obtain food reward. The timing of the pecks and the food reward signals were recorded in a log file using standard equipment. The Kinect-based system, called BehaviorWatch, also measured the pecking and feeding behavior and generated a different log file. For key pecking, BehaviorWatch had an average sensitivity of 95% and a precision of 91%, which were very similar to the pecking measurements from the standard equipment. For detecting feeding activity, BehaviorWatch had a sensitivity of 95% and a precision of 97%. These results allow us to demonstrate that an advantage of the Kinect-based approach is that it can also be reliably used to measure activity other than key pecking.

  10. Genetic characterization of coagulase-positive staphylococci isolated from healthy pigeons.

    Science.gov (United States)

    Kizerwetter-Świda, M; Chrobak-Chmiel, D; Rzewuska, M; Antosiewicz, A; Dolka, B; Ledwoń, A; Czujkowska, A; Binek, M

    2015-01-01

    Coagulase-positive staphylococci (CoPS) are opportunistic veterinary pathogens, of which Staphylococcus aureus, S. delphini and S. intermedius can be isolated from pigeons. The biochemical identification of S. delphini and S. intermedius isolates may be incorrect, because of their phenotypic similarity. The purpose of the present study was to isolate and identify CoPS from domestic and feral pigeons and to determine their genetic relatedness by PFGE. A total number of 31 isolates of CoPS were obtained, 15 were identified as S. delphini group B, six as S. aureus, four as S. delphini group A, three as S. intermedius and three as S. schleiferi subsp. coagulans. The results indicate that S. delphini group B is the predominant CoPS species among pigeons studied. PFGE restriction patterns of S. delphini group A and S. delphini group B form separate clusters, demonstrating their genetic heterogeneity. Indistinguishable or very similar PFGE patterns observed among S. delphini group B isolates from domestic and feral pigeons confirm the possibility of CoPS transmission between these birds.

  11. Serial learning with a wild card by pigeons (Columba livia): effect of list length.

    Science.gov (United States)

    Terrace, H S; Chen, S; Newman, A B

    1995-06-01

    Pigeons (Columba livia) learned 3-, 4- or 5-item lists prior to subset and wild card tests. On the latter, a novel item replaced 1 of the list items. Pigeons who learned 3-item lists responded accurately on all subset pairs (AB, BC, and AC) and on all types of 3-item wild card trials (WBC, AWC, & ABW). Pigeons who learned 4- and 5-item lists responded at chance levels of accuracy on all subsets that did not contain a start or an end item (BC, BD, & CD, respectively, on 4- and 5-item subset tests). On wild card trials, they exceeded chance levels of performance only when the wild card replaced the last item (ABCW & ABCDW trials). Monkeys (Cebus apella) trained to produce a 5-item list perform accurately on all subsets and wild cards. (M. R. D'Amato & M. Colombo, 1988, 1989). These differences provide strong evidence that pigeons and monkeys form qualitatively different representations of lists containing four or more items.

  12. Alterations in the Helicoverpa armigera midgut digestive physiology after ingestion of pigeon pea inducible leucine aminopeptidase.

    Directory of Open Access Journals (Sweden)

    Purushottam R Lomate

    Full Text Available Jasmonate inducible plant leucine aminopeptidase (LAP is proposed to serve as direct defense in the insect midgut. However, exact functions of inducible plant LAPs in the insect midgut remain to be estimated. In the present investigation, we report the direct defensive role of pigeon pea inducible LAP in the midgut of Helicoverpa armigera (Lepidoptera: Noctuidae and responses of midgut soluble aminopeptidases and serine proteinases upon LAP ingestion. Larval growth and survival was significantly reduced on the diets supplemented with pigeon pea LAP. Aminopeptidase activities in larvae remain unaltered in presence or absence of inducible LAP in the diet. On the contrary, serine proteinase activities were significantly decreased in the larvae reared on pigeon pea LAP containing diet as compared to larvae fed on diet without LAP. Our data suggest that pigeon pea inducible LAP is responsible for the degradation of midgut serine proteinases upon ingestion. Reduction in the aminopeptidase activity with LpNA in the H. armigera larvae was compensated with an induction of aminopeptidase activity with ApNA. Our findings could be helpful to further dissect the roles of plant inducible LAPs in the direct plant defense against herbivory.

  13. Differential magnetic field effects on heart rate and nociception in anosmic pigeons.

    Science.gov (United States)

    Del Seppia, Cristina; Mencacci, Resi; Luschi, Paolo; Varanini, Maurizio; Ghione, Sergio

    2012-05-01

    Several studies have shown that exposure to altered magnetic fields affects nociception by suppressing stress-induced hypoalgesia, and that this effect is reduced or abolished if the treatment is performed in the absence of light. This raises the question as to whether other sources of sensory stimuli may also modulate these magnetic effects. We investigated the possible role of olfaction in the magnetically induced effects on sensitivity to nociceptive stimuli and heart rate (HR) in restraint-stressed homing pigeons exposed to an Earth-strength, irregularly varying (<1 Hz) magnetic field. The magnetic treatment decreased the nociceptive threshold in normally smelling birds and an opposite effect was observed in birds made anosmic by nostril plugging. Conversely, no differential effect of olfactory deprivation was observed on HR, which was reduced by the magnetic treatment both in smelling and anosmic pigeons. The findings highlight an important role of olfactory environmental information in the mediation of magnetic effects on nociception, although the data cannot be interpreted unambiguously because of the lack of an additional control group of olfactory-deprived, non-magnetically exposed pigeons. The differential effects on a pigeon's sensitivity to nociceptive stimulus and HR additionally indicate that the magnetic stimuli affect nociception and the cardiovascular system in different ways.

  14. Depth to Transition--Pigeon Point to South Monterey Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the depth-to-transition map of the Pigeon Point to South Monterey Bay, California, region. The raster data file is included in...

  15. A family with extrinsic allergic alveolitis caused by wild city pigeons: A case report

    NARCIS (Netherlands)

    G.J. du Marchie Sarvaas; P.J.F.M. Merkus (Peter); J.C. de Jongste (Johan)

    2000-01-01

    textabstractWe describe a family in which the mother died of unresolved lung disease and whose 5 children, some of whom had previous signs of asthma, were subsequently affected by extrinsic allergic alveolitis caused by contact with wild city pigeon antigens. The children received

  16. Extensive Training Is Insufficient to Produce the Work-Ethic Effect in Pigeons

    Science.gov (United States)

    Vasconcelos, Marco; Urcuioli, Peter J.

    2009-01-01

    Zentall and Singer (2007a) hypothesized that our failure to replicate the work-ethic effect in pigeons (Vasconcelos, Urcuioli, & Lionello-DeNolf, 2007) was due to insufficient overtraining following acquisition of the high- and low-effort discriminations. We tested this hypothesis using the original work-ethic procedure (Experiment 1) and one…

  17. Characterization of five fungal endophytes producing Cajaninstilbene acid isolated from pigeon pea [Cajanus cajan (L.) Millsp].

    Science.gov (United States)

    Gao, Yuan; Zhao, Jin Tong; Zu, Yuan Gang; Fu, Yu Jie; Wang, Wei; Luo, Meng; Efferth, Thomas

    2011-01-01

    Five fungal endophytes (K4, K5, K6, K9, K14) producing Cajaninstilbene acid (CSA, 3-hydroxy-4-prenyl-5-methoxystilbene-2-carboxylic acid) were isolated from the roots of pigeon pea [Cajanus cajan (L.) Millsp.]. CSA is responsible for the prominent pharmacological activities in pigeon pea. The amount of CSA in culture solution varied among the five fungal endophytes. K4 produced the highest levels of CSA (1037.13 µg/L) among the endophytes tested after incubation for five days. Both morphological characteristics and molecular methods were used for species identification of fungal endophytes. The five endophytic isolates were characterized by analyzing the internal transcribed spacer (ITS) rRNA and β-tubulin genes. The K4, K5, K9 and K14 strains isolated from pigeon pea roots were found to be closely related to the species Fusarium oxysporum. K6 was identified as Neonectria macrodidym. The present study is the first report on the isolation and identification of fungal endophytes producing CSA in pigeon pea. The study also provides a scientific base for large scale production of CSA.

  18. Photopic spectral sensitivities of the red and the yellow field of the pigeon retina

    NARCIS (Netherlands)

    Wortel, J.F.; Wubbels, R.J.; Nuboer, J.F.W.

    1984-01-01

    The spectral sensitivities of the red field and the yellow field in the retina of the homing pigeon (Columba Livia) were determined on the basis of ERG responses. Between 450 and 550 nm the relative spectral sensitivity of the yellow field turned out to be higher than that of the red field. The resu

  19. Pigeon's (Columba livia) paradoxical preference for the suboptimal alternative in a complex foraging task.

    Science.gov (United States)

    Zentall, Thomas R; Case, Jacob P; Luong, Jasmine

    2016-05-01

    Recent research has examined a task in which choice of 1 alternative A provides reinforcement and in addition, allows access to alternative B that also provides reinforcement. However, although initial choice of B also provides reinforcement, it does not also allow access to A. Thus, optimal performance would be to always choose A. Curiously, Salwiczek et al. (2012) reported that adult wrasse (cleaner) fish mastered this task within 50 trials, whereas monkeys and apes had great difficulty with it. The authors attributed the species differences to ecological differences in the species foraging experiences. However, Pepperberg and Hartsfield (2014) found that parrots too learned this task. In Experiment 1, using the manual presentation of stimuli, we found that pigeons actually showed a reliable preference for B, the suboptimal alternative. In Experiment 2, we replicated the suboptimal preference using an automated version of the task. We hypothesized that the pigeons may have been basing their preference on the frequency of reinforcement associated with each alternative (initially, all trials ended with choice of B, whereas only half of the trials involved choice of A). In Experiment 3, we tested the hypothesis that the pigeons' preference was influenced by the frequency of reinforcements associated with A and B. Thus, when the pigeon chose A, we replaced B with C, so reinforcement occurred to B only when they chose it first. With this procedure we found that B was no longer preferred over A. Thus, the data supported our hypothesis. (PsycINFO Database Record

  20. Change blindness in pigeons (Columba livia): the effects of change salience and timing.

    Science.gov (United States)

    Herbranson, Walter T

    2015-01-01

    Change blindness is a well-established phenomenon in humans, in which plainly visible changes in the environment go unnoticed. Recently a parallel change blindness phenomenon has been demonstrated in pigeons. The reported experiment follows up on this finding by investigating whether change salience affects change blindness in pigeons the same way it affects change blindness in humans. Birds viewed alternating displays of randomly generated lines back-projected onto three response keys, with one or more line features on a single key differing between consecutive displays. Change salience was manipulated by varying the number of line features that changed on the critical response key. Results indicated that change blindness is reduced if a change is made more salient, and this matches previous human results. Furthermore, accuracy patterns indicate that pigeons' effective search area expanded over the course of a trial to encompass a larger portion of the stimulus environment. Thus, the data indicate two important aspects of temporal cognition. First, the timing of a change has a profound influence on whether or not that change will be perceived. Second, pigeons appear to engage in a serial search for changes, in which additional time is required to search additional locations.

  1. Pathologic findings in racing pigeons (Columba livia domestica) with "young bird sickness".

    Science.gov (United States)

    Scullion, Francis T; Scullion, Mary Geraldine

    2007-03-01

    "Young bird sickness" is a term used by racing pigeon fanciers to describe a condition that has occurred regularly in recent years and affects pigeons (Columba livia domestica) in their first year of life. It is characterized by slow crop emptying, regurgitation, diarrhea, weight loss, poor performance, and occasionally death. Little scientific information is known about this syndrome to differentiate it from other diseases that occur in young pigeons. In this study, 1 bird from each of 9 lofts where "young bird sickness" was reported was euthanatized for cytologic and postmortem examination. Lesions of the lymphoreticular system, alimentary tract, and respiratory system were the most common findings. Lesions of the lymphoreticular system were present in all birds examined, and 3 birds had histopathologic findings consistent with circovirus infection. Combinations of protozoal, fungal, and mixed bacterial infections were associated with ingluvitis in 7 birds and enteritis in 6 birds. Pneumonitis was found in 5 birds that tested positive for Chlamydophila by polymerase chain reaction. Although "young bird sickness" appears to be a multifactorial condition, a pattern of lesions that involved the lymphoreticular, gastrointestinal, and respiratory systems was evident, whereas diseases of other organ systems were uncommon. These findings suggest that "young bird sickness" may have a common etiology, and circovirus infection is proposed as a possible initiating cause of this syndrome in young racing pigeons in Northern Ireland.

  2. Delay-Amount Tradeoffs in Choices by Pigeons and Rats: Hyperbolic versus Exponential Discounting

    Science.gov (United States)

    Mazur, James E.; Biondi, Dawn R.

    2009-01-01

    An adjusting-delay procedure was used to study the choices of pigeons and rats when both delay and amount of reinforcement were varied. In different conditions, the choice alternatives included one versus two reinforcers, one versus three reinforcers, and three versus two reinforcers. The delay to one alternative (the standard alternative) was…

  3. Flexible motor adjustment of pecking with an artificially extended bill in crows but not in pigeons

    Science.gov (United States)

    Matsui, Hiroshi

    2017-01-01

    The dextrous foraging skills of primates, including humans, are underpinned by flexible vision-guided control of the arms/hands and even tools as body-part extensions. This capacity involves a visuomotor conversion process that transfers the locations of the hands/arms and a target in retinal coordinates into body coordinates to generate a reaching/grasping movement and to correct online. Similar capacities have evolved in birds, such as tool use in corvids and finches, which represents the flexible motor control of extended body parts. However, the flexibility of avian head-reaching and bill-grasping with body-part extensions remains poorly understood. This study comparatively investigated the flexibility of pecking with an artificially extended bill in crows and pigeons. Pecking performance and kinematics were examined when the bill extension was attached, and after its removal. The bill extension deteriorated pecking in pigeons in both performance and kinematics over 10 days. After the bill removal, pigeons started bill-grasping earlier, indicating motor adaptation to the bill extension. Contrastingly, pecking in crows was deteriorated transiently with the bill extension, but was recovered by adjusting pecking at closer distances, suggesting a quick adjustment to the bill extension. These results indicate flexible visuomotor control to extended body parts in crows but not in pigeons. PMID:28386435

  4. Waiting time before release increases the motivation to home in homing pigeons (Columba livia).

    Science.gov (United States)

    Dell'Ariccia, Gaia; Costantini, David; Dell'Omo, Giacomo; Lipp, Hans-Peter

    2009-10-01

    When performing homing experiments with individual releases, pigeons have to wait in a transport box for a certain amount of time before being released and hence perceive the departure of companions. Quite often, the last pigeons disappear straightforward from the release site. The question is whether this reflects improved orientation because of prolonged exposure to the release place or whether it reflects increased homing motivation. By releasing pigeons from a familiar site, we investigated the effects of the time spent at the release site on homing performance, recording pigeons' flights with GPS loggers. Our results show that, despite individual peculiarities of flight patterns, the waiting time at release site had a positive effect on homing speed and time, and reduced the time spent circling around the release point. However, the overall path efficiency as derived from GPS tracking was not influenced. These results suggest that a longer waiting time before release improves homing performance and this is related not only to increased navigational abilities but also to increased homing motivation.

  5. Concept learning without differential reinforcement in pigeons by means of contextual cueing.

    Science.gov (United States)

    Couto, Kalliu C; Navarro, Victor M; Smith, Tatiana R; Wasserman, Edward A

    2016-04-01

    How supervision is arranged can affect the way that humans learn concepts. Yet very little is known about the role that supervision plays in nonhuman concept learning. Prior research in pigeon concept learning has commonly used differential response-reinforcer procedures (involving high-level supervision) to support reliable discrimination and generalization involving from 4 to 16 concurrently presented photographic categories. In the present project, we used contextual cueing, a nondifferential reinforcement procedure (involving low-level supervision), to investigate concept learning in pigeons. We found that pigeons were faster to peck a target stimulus when 8 members from each of 4 categories of black-and-white photographs-dogs, trees, shoes, and keys-correctly cued its location than when they did not. This faster detection of the target also generalized to 4 untrained members from each of the 4 photographic categories. Our results thus pass the prime behavioral tests of conceptualization and suggest that high-level supervision is unnecessary to support concept learning in pigeons.

  6. Screening for several potential pathogens in feral pigeons (Columba livia in Madrid

    Directory of Open Access Journals (Sweden)

    Ballesteros Carlos

    2010-06-01

    Full Text Available Abstract Background Pathogens with the zoonotic potential to infect humans, such as Campylobacter jejuni, Campylobacter coli and Chlamydophila psittaci, can be found in feral pigeons (Columba livia. Given the high density of these birds in the public parks and gardens of most cities, they may pose a direct threat to public health. Methods A total of 118 pigeons were captured in three samplings carried out in 2006-2007 in public parks and gardens in Madrid, Spain. Standard haematological and morphological analyses were carried out on the pigeons. PCR was used to screen for the presence of Campylobacter jejuni, C. coli and Chlamydophila psittaci. Positive samples were confirmed by DNA sequencing. Results The analyses demonstrated a high prevalence of Chlamydophila psittaci (52.6% and Campylobacter jejuni (69.1% among the birds captured. In contrast, Campylobacter coli was rarely detected (1.1%. Conclusions Pigeons in Madrid can carry Chlamydophila psittaci and Campylobacter jejuni. They may be asymptomatic or subclinical carriers of both pathogens.

  7. DEVELOPMENT OF PIGEON PEA INOCULATED WITH RHIZOBIUM ISOLATED FROM COWPEA TRAP HOST PLANTS

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    SALOMÃO LIMA GUIMARÃES

    2016-01-01

    Full Text Available Pigeon pea is an important protein source grown in several tropical and sub - tropical countries, and is considered a multi - purpose plant that is resistant to the conditions of the Brazilian Cerrado. Among the possible uses for cowpea, its use as a green manure, increasing soil nitrogen content through the association with diazotrophic bacteria, generically known as rhizobia, is noteworthy. The present work aimed to evaluate the efficiency of Rhizobium strains isolated from cowpea plants in the development of pigeon peas cultured in Red Latosol. The experiment was conducted in a greenhouse, using a completely randomized design with seven treatments and four replications. Treatments consisted of inoculation with four Rhizobium strains (MT8, MT15, MT16, and MT23 and one commercial inoculant comprising Bradyrhizobium spp. strains BR 2801 and BR 2003. There were two controls, one absolute (without inoculation or nitrogen fertilization and the other with nitrogen fertilization. Each experimental plot consisted of an 8 - dm 3 vase containing three plants. Analyzed variables included plant height, SPAD index, number and dry weight of nodules, and shoot and root dry masses. Pigeon peas responded significantly to inoculation treatment, since all the plants inoculated with Rhizobium strains isolated from cowpea strains showed results similar to plants in the nitrogen control and commercial inoculant treatments. This demonstrates a favorable plant – bacteria interaction, which can be utilized as an alternative nitrogen source for pigeon peas.

  8. Biological control of fusarial wilt of pigeon pea by Bacillus brevis.

    Science.gov (United States)

    Bapat, S; Shah, A K

    2000-02-01

    A virulent strain of pigeon pea wilt pathogen was isolated from wilted pigeon pea plants and was identified as Fusarium oxysporum f. sp. udum. Many bacterial cultures showing antagonism to the pathogen were isolated from various ecological niches. When tested under pot and field conditions, development of fusarial wilt symptoms was prevented in pigeon pea seeds treated with one such antagonist, Bacillus brevis. A formulation of B. brevis with vermiculite as a carrier had a shelf life of at least 6 months. Bacillus brevis produced an extracellular antagonistic substance which induced swelling of the pathogen's hyphal tips, and cells were bulbous and swollen with shrunken and granulated cytoplasm. The antagonistic substance also inhibited germination of conidia, and was fungicidal to the vegetative mycelia of the pathogen. Comparison of the properties of our antagonistic substance with that of known antibiotics produced by B. brevis suggests that our antagonistic substance is a novel compound. The observations reported here indicate that this strain of B. brevis may have potential as a biocontrol agent against fusarial wilt in pigeon pea.

  9. The ethics of reviving long extinct species.

    Science.gov (United States)

    Sandler, Ronald

    2014-04-01

    There now appears to be a plausible pathway for reviving species that have been extinct for several decades, centuries, or even millennia. I conducted an ethical analysis of de-extinction of long extinct species. I assessed several possible ethical considerations in favor of pursuing de-extinction: that it is a matter of justice; that it would reestablish lost value; that it would create new value; and that society needs it as a conservation last resort. I also assessed several possible ethical arguments against pursuing de-extinction: that it is unnatural; that it could cause animal suffering; that it could be ecologically problematic or detrimental to human health; and that it is hubristic. There are reasons in favor of reviving long extinct species, and it can be ethically acceptable to do so. However, the reasons in favor of pursuing de-extinction do not have to do with its usefulness in species conservation; rather, they concern the status of revived species as scientific and technological achievements, and it would be ethically problematic to promote de-extinction as a significant conservation strategy, because it does not prevent species extinctions, does not address the causes of extinction, and could be detrimental to some species conservation efforts. Moreover, humanity does not have a responsibility or obligation to pursue de-extinction of long extinct species, and reviving them does not address any urgent problem. Therefore, legitimate ecological, political, animal welfare, legal, or human health concerns associated with a de-extinction (and reintroduction) must be thoroughly addressed for it to be ethically acceptable. © 2013 Society for Conservation Biology.

  10. Isolation, histopathology and antibiogram of Escherichia coli from pigeons (Columba livia

    Directory of Open Access Journals (Sweden)

    Pankaj Dutta

    2013-04-01

    Full Text Available Aim: To know the prevalence of antibiotic resistant Escherichia coli among dead and/or diarrhoic pigeons in and around greater Guwahati. Materials and Methods: Samples were cultured from dead and/or diarrhoic pigeons and identification was done by standard methods. The sensitivity of the isolated E.coli strains to 15 antibiotics of human and veterinary use was also determined. Organs from those dead birds from which E.coli were recovered were processed according to the routine procedure for histopathological studies. Results: Out of 150 pigeons subjected to microbiological investigation, 91(60.67 % samples were found positive for E. coli.The most frequently occurring serotypes were O157 (9.89%, followed by O68, O121 (7.69%, O9, O75, O131 (5.49%, O2, O13, O22 (3.30%. Antibiogram investigation of the isolates revealed that 91isolates (100% exhibited resistance against Ampicillin followed by Nitro-furantoin (73.62%, Tetracycline (65.93 %, Oxytetracycline (62.63 % and Streptomycin (61.54. Gross changes of some birds showed fibrinous pericarditis and perihepatitis and coligranuloma in different organs like liver and serosal surface of intestine. Microscopically, severe congestion and haemorrhages in different organs such as liver, kidney, lung and intestine. In some cases thick layer of fibrinous exudates with large number of heterophills over the surface of liver and heart with early degenerative changes as well as focal necrosis. Conclusion: The result of this study suggests that antimicrobial-resistant pathogenic E.coli is present in pigeons in and around greater Guwahati. Surveillance programs may be introduced to monitor antimicrobial resistance of pathogenic E.coli in pigeons in and around greater guwahati. [Vet World 2013; 6(2.000: 91-94

  11. Effects of sodium valproate and carbamazepine on food competition aggression in pigeons

    Directory of Open Access Journals (Sweden)

    C. Fachinelli

    2007-06-01

    Full Text Available Valproate and carbamazepine (CAR have been proposed as adjunct alternatives for the control of aggression in psychiatric patients, although no definite conclusions have been reached. We examined the effects of these drugs on food competition offensive aggression and other behaviors in high- and low-aggression food-restricted pigeons. These were divided into pairs containing previously ranked high-aggression (N = 10 pairs and low-aggression females (N = 10 pairs. In Experiment 1, a pigeon in each pair of high- and low-aggression subjects was treated daily with an oral dose of sodium valproate (50 mg kg-1 mL saline-1 for 15 days. The other animal received the vehicle. On days 1, 7, and 15, food competition trials (10 min were performed 60 min after treatment. In Experiment 2, one pigeon in each pair was treated daily with an oral dose of CAR (20 mg kg-1 mL saline-1 for 15 days. Each pair was submitted to a food competition trial on days 1, 7, and 15 of treatment. Valproate (15 days of treatment selectively decreased the time spent in offensive aggression (control: 102.7 ± 9.3 vs valproate: 32.7 ± 9.2 s; P < 0.001, ANOVA-2-TAU of high-aggression pigeons. This was also the case for 7 and 15 days of CAR treatment (control: 131.5 ± 8.9 vs CAR: 60.4 ± 5.3, P < 0.01, and control: 122.7 ± 7.1 vs CAR: 39.1 ± 5.2; P < 0.001, ANOVA-2-TAU, respectively. Thus, the two anticonvulsive drugs have a similar effect on food competition aggression in pigeons.

  12. Manipulation of primary sex ratio in birds: lessons from the homing pigeon (Columba livia domestica).

    Science.gov (United States)

    Goerlich-Jansson, Vivian C; Müller, Martina S; Groothuis, Ton G G

    2013-12-01

    Across various animal taxa not only the secondary sex ratio but also the primary sex ratio (at conception) shows significant deviations from the expected equal proportions of sons and daughters. Birds are especially intriguing to study this phenomenon as avian females are the heterogametic sex (ZW); therefore sex determination might be under direct control of the mother. Avian sex ratios vary in relation to environmental or maternal condition, which can also affect the production of maternal steroids that in turn are involved in reproduction and accumulate in the developing follicle before meiosis. As the proximate mechanisms underlying biased primary sex ratio are largely elusive, we explored how, and to what extent, maternal steroid hormones may be involved in affecting primary or secondary sex ratio in clutches of various species of pigeons. First we demonstrated a clear case of seasonal change in sex ratio in first eggs both in the Rock Pigeon (Columba livia) and in a related species, the Wood Pigeon (Columba palumbus), both producing clutches of two eggs. In the Homing Pigeon (Columba livia domestica), domesticated from the Rock Pigeon, testosterone treatment of breeding females induced a clear male bias, while corticosterone induced a female bias in first eggs and we argue that this is in line with sex allocation theory. We next analyzed treatment effects on follicle formation, yolk mass, and yolk hormones, the latter both pre- and post-ovulatory, in order to test a diversity of potential mechanisms related to both primary and secondary sex ratio manipulation. We conclude that maternal plasma hormone levels may affect several pre-ovulatory mechanisms affecting primary sex ratio, whereas egg hormones are probably involved in secondary sex ratio manipulation only.

  13. The antitrichomonal efficacy of garlic and metronidazole against Trichomonas gallinae infecting domestic pigeons.

    Science.gov (United States)

    Seddiek, Sh A; El-Shorbagy, Mohamed M; Khater, Hanem F; Ali, Ali M

    2014-04-01

    Trichomonas gallinae is the causative agent of canker in pigeon. This work was carried out to investigate in the vitro and in vivo efficacy of aqueous water extract of garlic (AGE) on the growth of T. gallinae infecting pigeons compared to those of metronidazole (MTZ). MTZ and AGE were added, at different concentrations, to glucose-serum broth medium containing 1 × 10(4) trophozoites/ml. In the in vivo experiment, 48 squabs were grouped into four groups. The first group (gr. I) was not infected and not treated. Each squab of the other group was infected with 1 × 10(4) trophozoites. The second group (gr. II) was infected and not treated. On day 0, the third group (gr. III) was treated with MTZ (50 mg/kg BW) and the fourth group (gr. IV) was treated with AGE (200 mg/kg BW) for seven successive days in drinking water. In vitro study revealed that the MLC, 24, 48, and 72 h post treatment were 50, 25, and 12.5 μg/ml, respectively, for MTZ and 75, 50, and 50 mg/ml, respectively, for AGE. Garlic (200 mg/kg BW) had the highest antitrichomonal effect and shortened course of treatment of pigeons from 7 days in gr. III to 5 days. Squabs in gr. II suffered from macrocytic hypochromic anemia, whereas squabs in grs. III and IV showed normal blood pictures. Serum total protein, albumin, and globulin were increased, whereas AST, ALT, and the total cholesterol were decreased in grs. III and IV when compared to those of gr. II. Pigeons protected with AGE showed increased body weight and reduced mortality percentage than the other groups. Our results indicated that garlic may be a promising phytotherapeutic agent for protection against trichomoniasis in pigeons.

  14. Dual-pathogen etiology of avian trichomonosis in a declining band-tailed pigeon population.

    Science.gov (United States)

    Girard, Yvette A; Rogers, Krysta H; Woods, Leslie W; Chouicha, Nadira; Miller, Woutrina A; Johnson, Christine K

    2014-06-01

    The Pacific Coast band-tailed pigeon (Patagioenas fasciata monilis) is a migratory game bird of North America that is at risk for population decline. Epidemics of avian trichomonosis caused by upper digestive tract infection with Trichomonas spp. protozoa in these and other doves and pigeons of the United States are sporadic, but can involve tens of thousands of birds in a single event. Herein, we analyze the role of trichomonosis in band-tailed pigeon mortality and relate spatial, temporal and demographic patterns of parasite transmission to the genetic background of the infecting organism. Infections were most common in adult birds and prevalence was high in band-tailed pigeons sampled at mortality events (96%) and rehabilitation centers (36%) compared to those that were hunter-killed (11%) or live-caught (4%). During non-epidemic periods, animals were primarily infected with T. gallinae Fe-hydrogenase subtype A2, and were less often infected with either T. gallinae subtype A1 (the British finch epidemic strain), T. stableri n. sp. (a T. vaginalis-like species), or Tritrichomonas blagburni n. sp.-like organisms. Birds sampled during multiple epidemics in California were only infected with T. gallinae subtype A2 and T. stableri. The non-clonal etiology of avian trichomonosis outbreaks in band-tailed pigeons and the risk of spill-over to raptor and passerine species highlights the need for additional studies that clarify the host range and evolutionary relationships between strains of Trichomonas spp. in regions of trichomonosis endemicity. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Aircraft passenger comfort experience: underlying factors and differentiation from discomfort.

    Science.gov (United States)

    Ahmadpour, Naseem; Robert, Jean-Marc; Lindgaard, Gitte

    2016-01-01

    Previous studies defined passengers' comfort based on their concerns during the flight and a set of eight experiential factors such as 'peace of mind', 'physical wellbeing', 'pleasure', etc. One Objective of this paper was to determine whether the factors underlying the passengers' experience of comfort differ from those of discomfort. Another objective was to cross-validate those factors. In the first study, respondents provided written reports of flight comfort and discomfort experiences separately and gave ratings on the impact of the eight factors on each experience. Follow up interviews were also conducted. Significant difference was found between comfort and discomfort ratings for two factors of 'pleasure', denoted by one's concern for stimulation, ambience and exceeded expectations, and 'physical wellbeing' characterized in terms of bodily support and energy. However, there were no significant differences between the comfort and discomfort ratings on the other six factors. The evidence does not support the proposition that passenger comfort and discomfort are underline by different sets of factors. It is therefore suggested that the evaluation of overall passenger comfort experience, as a whole, employ one spectrum ranging from extreme comfort to discomfort. In study two, a pool of comfort descriptors was collected. Those that were less relevant to passenger comfort were eliminated in a number of steps. Factor analysis was used to classify the remaining descriptors, using respondents' ratings on their potential impact on passenger comfort. Seven factors corresponded to the pre-determined passenger comfort factors from previous research, validating those with an exception of 'proxemics' (concerning one's privacy and control over their situation) but it was argued that this is due to the nature of the factor itself, which is context dependent and generally perceived unconsciously.

  16. Passenger Rail Service Comfortability in Kuala Lumpur Urban Transit System

    Directory of Open Access Journals (Sweden)

    Nordin Noor Hafiza

    2016-01-01

    Full Text Available Rail transit transportation system is among the public transportation network in Kuala Lumpur City. Some important elements in establishing this system are ticket price, operation cost, maintenance implications, service quality and passenger’s comfortability. The level of passenger’s comfortability in the coach is important to be considered by the relevant authorities and system operators in order to provide comfort and safety to passengers. The objective this research is to study some parameters that impact the comfortability of passengers and to obtain feedbacks from passengers for different rail transit system. Site observations were conducted to obtain data such as noise, vibration, speed and coach layouts which will be verified by using the passenger feedback outcomes. The research will be focused in and around the Kuala Lumpur City for the duration of 10 months. Four rail transit systems were being considered, i.e. Train Type A (LRA, Train Type B (LRB, Train Type C (MRL and Train Type D (CTR. Data parameters obtained from field observations were conducted in the rail coaches during actual operation using apparatus among others the sound level meter (SLM, vibration analyzer (VA and the global positioning system (GPS. Questionnaires were prepared as passenger feedback instrument, focusing on the level of comfortability in rail coaches. The outcomes of these analyses showed that CTR was the best and most comfortable coach, followed by LRA, LRB and MRL. Using the passenger feedbacks (MBP it was also found that the ranking values for the railway transit system using Rail Coach Comfortability (RCC is RCC (MBP were the same as the outcomes using the RCC (parameters. In conclusion, it was found that this research has successfully determined the level of comfortability as determined in its aim and objectives. From this research, it is hoped that the relevant authorities will continue to find ways to enhance the comfortability and safety of its

  17. Acute, fatal Sarcocystis calchasi-associated hepatitis in Roller pigeons (Columbia livia f. dom.) at Philadelphia Zoo

    Science.gov (United States)

    Four Roller pigeons (Columba livia f. dom.) at the Philadelphia Zoo died suddenly. Necropsy examination revealed macroscopic hepatitis. Microscopically, the predominant lesions were in liver, characterized with necrosis and mixed cell inflammatory response. Sarcocystis calchasi-like schizonts and fr...

  18. A lesson in defining "extinct"

    OpenAIRE

    Asimow, Paul D.

    2014-01-01

    Toni Feder’s Issues and Events news item about the High-Altitude Water Cherenkov Gamma-Ray Observatory under construction in Mexico ( Physics Today, October 2013, page 22) begins by describing the site as “nestled at 4100 m on the slopes of Sierra Negra, an extinct volcano.” However, as the picture accompanying her piece or a cursory examination in Google Earth makes clear, the site is not on the slopes of Sierra Negra. It sits in the saddle between Sierra Negra and its much larger companion ...

  19. Econometric Forecasting Models for Air Traffic Passenger of Indonesia

    Directory of Open Access Journals (Sweden)

    Viktor Suryan

    2017-01-01

    Full Text Available One of the major benefits of the air transport services operating in bigger countries is the fact that they provide a vital social economic linkage. This study is an attempt to establish the determinants of the passenger air traffic in Indonesia. The main objective of the study is to determine the economic variables that affect the number of airline passengers using the econometrics model of projection with an emphasis on the use of panel data and to determine the economic variables that affect the number of airline passengers using the econometrics model of projection with an emphasis on the use of time series data. This research also predicts the upcoming number of air traffic passenger until 2030. Air transportation and the economic activity in a country are interdependent. This work first uses the data at the country level and then at the selected airport level for review. The methodology used in this study has adopted the study for both normal regression and panel data regression techniques. Once all these steps are performed, the final equation is taken up for the forecast of the passenger inflow data in the Indonesian airports. To forecast the same, the forecasted numbers of the GDP (Gross Domestic Product and population (independent variables were chosen as a part of the literature review exercise are used. The result of this study shows the GDP per capita have significant related to a number of passengers which the elasticity 2.23 (time-series data and 1.889 for panel data. The exchange rate variable is unrelated to a number of passengers as shown in the value of elasticity. In addition, the total of population gives small value for the elasticity. Moreover, the number of passengers is also affected by the dummy variable (deregulation. With three scenarios: low, medium and high for GDP per capita, the percentage of growth for total number of air traffic passenger from the year 2015 to 2030 is 199.3%, 205.7%, and 320.9% respectively.

  20. Extinction by the long dielectric needles

    CERN Document Server

    Cherkas, Nadejda L

    2016-01-01

    Electromagnetic wave extinction by the very long but finite dielectric needle is compared with that by the infinite dielectric cylinder for an oblique incidence of the electromagnetic wave. It is shown that the renormalized Hankel functions without the logarithmic terms should be used for the calculation of the extinction per unit length of the infinite dielectric cylinder to apply it for extinction calculations by the finite dielectric cylinder.

  1. Resistance to extinction and behavioral momentum

    OpenAIRE

    Nevin, John A.

    2012-01-01

    In the metaphor of behavioral momentum, reinforcement is assumed to strengthen discriminated operant behavior in the sense of increasing its resistance to disruption, and extinction is viewed as disruption by contingency termination and reinforcer omission. In multiple schedules of intermittent reinforcement, resistance to extinction is an increasing function of reinforcer rate, consistent with a model based on the momentum metaphor. The partial-reinforcement extinction effect, which opposes ...

  2. Mass Extinctions vs. Uniformitarianism in Biological Evolution

    OpenAIRE

    Bak, Per; Paczuski, Maya

    1996-01-01

    It is usually believed that Darwin's theory leads to a smooth gradual evolution, so that mass extinctions must be caused by external shocks. However, it has recently been argued that mass extinctions arise from the intrinsic dynamics of Darwinian evolution. Species become extinct when swept by intermittent avalanches propagating through the global ecology. These ideas are made concrete through studies of simple mathematical models of coevolving species. The models exhibit self-organized criti...

  3. Extinction Maps in the WFAU Archives

    CERN Document Server

    Cross, Nicholas

    2015-01-01

    A brief set of notes about the database design for 3D maps of dust extinction in the WFAU Archives, which support data from UKIRT-WFCAM, VISTA and VST. The notes also detail typical use cases, such as getting colour-excesses, extinction-corrections, spectral energy distributions and colour-magnitude diagrams and demonstrate the SQL queries to return data, along with examples from VVV DR2 with bulge extinction maps from Chen et al. (2013).

  4. The Astronomical Pulse of Global Extinction Events

    Directory of Open Access Journals (Sweden)

    David F.V. Lewis

    2006-01-01

    Full Text Available The linkage between astronomical cycles and the periodicity of mass extinctions is reviewed and discussed. In particular, the apparent 26 million year cycle of global extinctions may be related to the motion of the solar system around the galaxy, especially perpendicular to the galactic plane. The potential relevance of Milankovitch cycles is also explored in the light of current evidence for the possible causes of extinction events over a geological timescale.

  5. The astronomical pulse of global extinction events.

    Science.gov (United States)

    Lewis, David F V; Dorne, Jean-Lou C M

    2006-06-23

    The linkage between astronomical cycles and the periodicity of mass extinctions is reviewed and discussed. In particular, the apparent 26 million year cycle of global extinctions may be related to the motion of the solar system around the galaxy, especially perpendicular to the galactic plane. The potential relevance of Milankovitch cycles is also explored in the light of current evidence for the possible causes of extinction events over a geological timescale.

  6. Isolation and characterization of Ornithobacterium rhinotracheale in the commercial turkey, quail flocks and domestic pigeons by bacteriological and molecular methods

    Directory of Open Access Journals (Sweden)

    Banani, M.

    2011-12-01

    Full Text Available Ornithobacterium rhinotracheale (ORT is a respiratory pathogen which has been isolated throughout the world from numerous bird species. The present study was designed to isolate and characterize the ORT from domestic turkeys, quails and pigeons. For this purpose, 250 samples from each bird species (turkey, quail and pigeon with or without respiratory signs were tested by taking of tracheal swabs. In addition, respiratory tissue samples (tracheal and lung, from 250 slaughtered turkeys, 50 slaughtered quails and 100dead pigeons were also subjected to culture for ORT as tracheal swabs. Respiratory tissues were also tested for bacterial DNA by using polymerase chain reaction (PCR. In general, 30 isolates including 4 isolates from turkeys, 3 isolates from quails and 23 isolates from pigeons were identified as ORT by bacteriologicalmethod and then confirmed by PCR. Bacterial DNA was detected in 20%, 50% and 35% of respiratory tissues in turkeys, quails and pigeons respectively. Five ORT isolates from pigeon and all four isolates from turkey showed smaller colony size, while other isolates had larger colonies when cultured in blood agar. Fifty percent of the isolates with larger colony but none of the isolates with small colony size could agglutinate red blood cells (RBCs. All of the isolates were sensitive to danofloxacin and chloramphenicolwhile more than 90% of pigeon isolates were resistant to ampicillin. All of turkey and quail and 30% of pigeon isolates were resistant to tetracycline. Our ORT isolates showed high identity (98%- 100% insequence of 16S rRNA gene to related data in GeneBank.

  7. Parasite distribution and early-stage encephalitis in Sarcocystis calchasi infections in domestic pigeons (Columba livia f. domestica).

    Science.gov (United States)

    Maier, Kristina; Olias, Philipp; Enderlein, Dirk; Klopfleisch, Robert; Mayr, Sylvia L; Gruber, Achim D; Lierz, Michael

    2015-01-01

    Pigeon protozoal encephalitis is a biphasic, neurologic disease of domestic pigeons (Columba livia f. domestica) caused by the apicomplexan parasite Sarcocystis calchasi. Despite severe inflammatory lesions of the brain, associated parasitic stages have only rarely been identified and the cause of the lesions is still unclear. The aim of this study was therefore to characterize the tissue distribution of S. calchasi within pigeons between the two clinical phases and during the occurrence of neurological signs. For this purpose, a semi-quantitative real-time polymerase chain reaction (PCR) was developed. Forty-five domestic pigeons were infected orally (via a cannula into the crop) with 200 S. calchasi sporocysts and euthanized in groups of three pigeons at intervals of 2 to 10 days over a period of 61 days. Tissue samples including brain and skeletal muscle were examined by histology, immunohistochemistry, and PCR. Schizonts were detected in the liver of one pigeon at day 10 post infection. A mild encephalitis was detected at day 20 post infection, around 4 weeks before the onset of neurological signs. At the same time, immature sarcocysts were present in the skeletal muscle. In seven pigeons a few sarcocysts were identified in the brain, but not associated with any lesion. These results suggest that the encephalitis is induced at a very early stage of the S. calchasi lifecycle rather than in the chronic phase of pigeon protozoal encephalitis. Despite the increasing severity of lesions in the central nervous system, the amount of sarcocysts did not increase. This supports the hypothesis of a delayed-type hypersensitivity response as the cause of the encephalitis. The study also demonstrated that S. calchasi DNA is detectable in tissues negative by histological methods, indicating a higher sensitivity of the real-time PCR.

  8. Airline policy for passengers requiring supplemental in-flight oxygen.

    Science.gov (United States)

    Walker, Jacqueline; Kelly, Paul T; Beckert, Lutz

    2009-05-01

    The aim of this study was to investigate the current Australian/New Zealand airline policy on supplemental in-flight oxygen for passengers with lung disease. Fifty-four commercial airlines servicing international routes were surveyed. Information was gathered from airline call centres and web sites. The survey documented individual airline policy on in-flight oxygen delivery, approval schemes, equipment and cost. Of the 54 airlines contacted, 43 (81%) were able to support passengers requiring in-flight oxygen. The majority (88%) of airlines provided a cylinder for passengers to use. Airline policy for calculating the cost of in-flight oxygen differed considerably between carriers. Six (14%) airlines supplied oxygen to passengers free of charge; however, three of these airlines charged for an extra seat. Fifteen airlines (35%) charged on the basis of oxygen supplied, that is, per cylinder. Fourteen airlines (33%) had a flat rate charge per sector. This study confirmed that most airlines can accommodate passengers requiring supplemental oxygen. However, the findings highlight inconsistencies in airline policies and substantial cost differences for supplemental in-flight oxygen. We advocate an industry standardization of policy and cost of in-flight oxygen.

  9. Convenient Airports: Point of View of the Passengers

    Science.gov (United States)

    Magri, Adival Aparecido, Jr.; Alves, Claudio Jorge Pinto

    2003-01-01

    The competition among airlines or among airports aiming at to increase the demand for its services has been more and more incited. Knowledge the perception of the users for the offered services means to meet the customer's needs and expectations in order either to keep the customer, and therefore keep a significant advantage over competitors. The passenger of the air transportation wants rapidity, security and convenience. Convenience can be translated by comfort that the passenger wants for the price that he can pay. In this paper had been identified. as a result of a survey achieved in six Brazilian airports during 2002, the best indicators in the passenger's perception. These indicators among any others were listed m the handbook of Airports Council International (ACI). Distinctive perceptions were observed among passengers with different travel motivations. This survey had been carried through in the airports of Brasilia, Porto Alegre, Salvador. Fortaleza, Curitiba and Bel6m. Considering this survey we can identified the most attractive airport among them. This work is a way to help improve quality of service, in particular, m these six airports of the Brazilian network. The results should be published and made available to all the parties concerned (airport authority, airlines and service providers) and should lead to corrective action when the passenger is not satisfied with the service.

  10. Mass extinctions vs. uniformitarianism in biological evolution

    Energy Technology Data Exchange (ETDEWEB)

    Bak, P.; Paczuski, M.

    1995-12-31

    It is usually believed that Darwin`s theory leads to a smooth gradual evolution, so that mass extinctions must be caused by external shocks. However, it has recently been argued that mass extinctions arise from the intrinsic dynamics of Darwinian evolution. Species become extinct when swept by intermittent avalanches propagating through the global ecology. These ideas are made concrete through studies of simple mathematical models of co-evolving species. The models exhibit self-organized criticality and describe some general features of the extinction pattern in the fossil record.

  11. Enhancing Divergent Search through Extinction Events

    DEFF Research Database (Denmark)

    Lehman, Joel; Miikkulainen, Risto

    2015-01-01

    A challenge in evolutionary computation is to create representations as evolvable as those in natural evolution. This paper hypothesizes that extinction events, i.e. mass extinctions, can significantly increase evolvability, but only when combined with a divergent search algorithm, i.e. a search...... for the capacity to evolve. This hypothesis is tested through experiments in two evolutionary robotics domains. The results show that combining extinction events with divergent search increases evolvability, while combining them with convergent search offers no similar benefit. The conclusion is that extinction...

  12. Secondary extinction in Pavlovian fear conditioning.

    Science.gov (United States)

    Vurbic, Drina; Bouton, Mark E

    2011-09-01

    Pavlov (1927/1960) reported that following the conditioning of several stimuli, extinction of one conditioned stimulus (CS) attenuated responding to others that had not undergone direct extinction. However, this secondary extinction effect has not been widely replicated in the contemporary literature. In three conditioned suppression experiments with rats, we further explored the phenomenon. In Experiment 1, we asked whether secondary extinction is more likely to occur with target CSs that have themselves undergone some prior extinction. A robust secondary extinction effect was obtained with a nonextinguished target CS. Experiment 2 showed that extinction of one CS was sufficient to reduce renewal of a second CS when it was tested in a neutral (nonextinction) context. In Experiment 3, secondary extinction was observed in groups that initially received intermixed conditioning trials with the target and nontarget CSs, but not in groups that received conditioning of the two CSs in separate sessions. The results are consistent with the hypothesis that CSs must be associated with a common temporal context during conditioning for secondary extinction to occur.

  13. Dust Extinction in Compact Planetary Nebulae

    OpenAIRE

    Lee, TH; Kwok, S.

    2005-01-01

    The effects of dust extinction on the departure from axisymmetry in the morphology of planetary nebulae (PNs) are investigated through a comparison of the radio free-free emission and hydrogen recombination line images. The dust extinction maps from five compact PNs are derived using high-resolution (̃0"1) Hα and radio maps of the HST and VLA. These extinction maps are then analyzed by an ellipsoidal shell ionization model including the effects of dust extinction to infer the nebulae's intrin...

  14. Climate predictors of late quaternary extinctions

    DEFF Research Database (Denmark)

    Nogués-Bravo, David; Ohlemüller, Ralf; Batra, Persaram

    2010-01-01

    Between 50,000 and 3,000 years before present (BP) 65% of mammal genera weighing over 44 kg went extinct, together with a lower proportion of small mammals. Why species went extinct in such large numbers is hotly debated. One of the arguments proposes that climate changes underlie Late Quaternary...... extinctions, but global quantitative evidence for this hypothesis is still lacking. We test the potential role of global climate change on the extinction of mammals during the Late Quaternary. Our results suggest that continents with the highest climate footprint values, in other words, with climate changes...

  15. Long-term maintenance of immediate or delayed extinction is determined by the extinction-test interval

    OpenAIRE

    Johnson, Justin S.; Escobar, Martha; Kimble, Whitney L.

    2010-01-01

    Short acquisition-extinction intervals (immediate extinction) can lead to either more or less spontaneous recovery than long acquisition-extinction intervals (delayed extinction). Using rat subjects, we observed less spontaneous recovery following immediate than delayed extinction (Experiment 1). However, this was the case only if a relatively long extinction-test interval was used; a relatively short extinction-test interval yielded the opposite result (Experiment 2). Previous data appear co...

  16. Quality evaluation of stiff porridges prepared from Irish potato (Solanum tuberosum) and pigeon pea (Cajanus cajan) starch blends.

    Science.gov (United States)

    Abu, Joseph Oneh; Enyinnaya, Chinma Chiemela; James, Samaila; Okeleke, Ezinne

    2012-06-01

    Quality attributes of stiff porridges prepared from Irish potato and pigeon pea starch blends were studied. Starches were extracted from Irish potato and pigeon pea using a wet extraction method. Various ratios of the starches were mixed and analyzed for chemical, functional and pasting properties. The starch blends were then prepared into stiff porridges for sensory evaluation using a 20-man sensory panel. Substitution of Irish potato starch with pigeon pea starch led to increases in protein (0.15 to 1.2%), fat (0.26 to 0.56%) and ash (0.30 to 0.69%) while the amylose content of the starch blends decreased (from 23.8 to 18.4%) respectively. Functional properties such as bulk density (0.75 to 0.60 g/cm(3)), water absorption capacity (3.1 to 2.6 g water/ g sample) and dispersibility (58.6 to 42.7%) decreased significantly (P stiff porridges were not adversely affected by pigeon pea starch inclusion. Therefore it should be possible to incorporate up to 50% of low digestible pigeon pea starch into Irish potato starch from legumes such as pigeon pea as alternatives to cassava starch in the preparation of stiff porridges. Such porridges made from Irish potato and legume starches could provide additional incentive for individuals requiring decreased and or slow starch digestibility such as diabetics.

  17. Occurrence of Bacterial and Viral Pathogens in Common and Noninvasive Diagnostic Sampling from Parrots and Racing Pigeons in Slovenia.

    Science.gov (United States)

    Dovč, Alenka; Jereb, Gregor; Krapež, Uroš; Gregurić-Gračner, Gordana; Pintarič, Štefan; Slavec, Brigita; Knific, Renata Lindtner; Kastelic, Marjan; Kvapil, Pavel; Mićunović, Jasna; Vadnjal, Stanka; Ocepek, Matjaž; Zadravec, Marko; Zorman-Rojs, Olga

    2016-06-01

    Airborne pathogens can cause infections within parrot (Psittaciformes) and pigeon (Columbiformes) holdings and, in the case of zoonoses, can even spread to humans. Air sampling is a useful, noninvasive method which can enhance the common sampling methods for detection of microorganisms in bird flocks. In this study, fecal and air samples were taken from four parrot holdings. Additionally, cloacal and oropharyngeal swabs as well as air samples were taken from 15 racing pigeon holdings. Parrots were examined for psittacine beak and feather disease virus (PBFDV), proventricular dilatation disease virus (PDDV), adenoviruses (AdVs), avian paramyxovirus type-1 (APMV-1), avian influenza virus (AIV), Chlamydia psittaci (CP), and Mycobacterium avium complex (MAC). MAC and AdVs were detected in three parrot holdings, CP was detected in two parrot holdings, and PBFDV and PDDV were each detected in one parrot holding. Pigeons were examined for the pigeon circovirus (PiCV), AdVs, and CP; PiCV and AdVs were detected in all investigated pigeon holdings and CP was detected in five pigeon holdings.

  18. Prevalence of Trichomonas spp. in domestic pigeons in Shandong Province, China, and genotyping by restriction fragment length polymorphism.

    Science.gov (United States)

    Jiang, Xiyue; Sun, Jingjing; Wang, Fangkun; Li, Hongmei; Zhao, Xiaomin

    2016-05-01

    Oropharyngeal swabs (n = 609) were collected randomly from 80,000 domestic pigeons (Columba livia domestica) on five pigeon farms and at one pigeon slaughterhouse in Shandong Province, China, from September 2012 to July 2013. Trichomonas spp. were detected in 206/609 (33.8%) samples. The prevalence was 14.9-31.1%, depending on different levels of sanitation and management, and was 4.8% in nestling pigeons, 13.6% in breeding pigeons and 35.2% in adolescent pigeons. Trichomonas gallinae genotypes A and B, and Trichomonas tenax-like isolates were identified by PCR-restriction fragment length polymorphism (RFLP) analysis and sequencing of the 5.8S rDNA-internal transcribed spacer (ITS) regions. RFLP analysis with the restriction enzyme BsiEI generated different RFLP band patterns between T. gallinae and T.tenax-like isolates. When BsiEI RFLP analysis was combined with HaeIII RFLP analysis, all infection types of T. gallinae and T.tenax-like isolates could be identified. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Conditioned discrimination of magnetic inclination in a spatial-orientation arena task by homing pigeons (Columba livia).

    Science.gov (United States)

    Mora, Cordula V; Acerbi, Merissa L; Bingman, Verner P

    2014-12-01

    It has been well established that homing pigeons are able to use the Earth's magnetic field to obtain directional information when returning to their loft and that their magnetic compass is based, at least in part, on the perception of magnetic inclination. Magnetic inclination has also been hypothesized in pigeons and other long-distance navigators, such as sea turtles, to play a role providing positional information as part of a map. Here we developed a behavioral paradigm which allows us to condition homing pigeons to discriminate magnetic inclination cues in a spatial-orientation arena task. Six homing pigeons were required to discriminate in a circular arena between feeders located either in a zone with a close to 0 deg inclination cue or in a zone with a rapidly changing inclination cue (-3 deg to +85 deg when approaching the feeder and +85 deg to -3 deg when moving away from the feeder) to obtain a food reward. The pigeons consistently performed this task above chance level. Control experiments, during which the coils were turned off or the current was running anti-parallel through the double-wound coil system, confirmed that no alternative cues were used by the birds in the discrimination task. The results show that homing pigeons can be conditioned to discriminate differences in magnetic field inclination, enabling investigation into the peripheral and central neural processing of geomagnetic inclination under controlled laboratory conditions.

  20. Effect of pigeon pea (Cajanus cajan L.) on high-fat diet-induced hypercholesterolemia in hamsters.

    Science.gov (United States)

    Dai, Fan-Jhen; Hsu, Wei-Hsuan; Huang, Jan-Jeng; Wu, She-Ching

    2013-03-01

    Obesity is associated with increased systemic and airway oxidative stress, which may result from a combination of adipokine imbalance and antioxidant defenses reduction. Obesity-mediated oxidative stress plays an important role in the pathogenesis of dyslipidemia, vascular disease, and nonalcoholic hepatic steatosis. The antidyslipidemic activity of pigeon pea were evaluated by high-fat diet (HFD) hamsters model, in which the level of high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), total cholesterol (TC), and total triglyceride (TG) were examined. We found that pigeon pea administration promoted cholesterol converting to bile acid in HFD-induced hamsters, thereby exerting hypolipidemic activity. In the statistical results, pigeon pea significantly increased hepatic carnitine palmitoyltransferase-1 (CPT-1), LDL receptor, and cholesterol 7α-hydroxylase (also known as cytochrome P450 7A1, CYP7A1) expression to attenuate dyslipidemia in HFD-fed hamsters; and markedly elevated antioxidant enzymes in the liver of HFD-induced hamsters, further alleviating lipid peroxidation. These effects may attribute to pigeon pea contained large of unsaturated fatty acids (UFA; C18:2) and phytosterol (β-sitosterol, campesterol, and stigmasterol). Moreover, the effects of pigeon pea on dyslipidemia were greater than β-sitosterol administration (4%), suggesting that phytosterone in pigeon pea could prevent metabolic syndrome.

  1. Free choice feeding of whole grains in meat-type pigeons: 1. effect on performance, carcass traits and organ development.

    Science.gov (United States)

    Xie, P; Jiang, X-Y; Bu, Z; Fu, S-Y; Zhang, S-Y; Tang, Q-P

    2016-10-11

    The effects of 5 different feeding systems on the performance, carcass traits and organ development were studied in pigeon squabs. The 5 treatments were (1) whole grains of maize, pea and wheat plus concentrate feed; (2)whole grains of maize and wheat plus concentrate feed (CWC); (3) whole grains of maize and pea plus concentrate feed; (4)whole grain of maize plus concentrate feed (CC); and (5) compound feed (CF). Feed intake of parent pigeons increased significantly from 0 to 21 d and it was higher in the CF treatment. Body weight of squabs in the CWC treatment was the highest among the 5 treatments in 4 weeks. Body weight losses of parental pigeons during the rearing period were not significantly different among the 5 treatments. Protein intake in CC and CWC treatments was lower than that of the other three treatments. The CWC treatment had the highest daily weight gain and the lowest feed conversion ratio. Treatments were statistically similar in the relative weight of carcass, breast and thigh. CF had the lower relative weight of abdominal fat. Relative weight of gizzard in the CF treatment was significantly lower than that of CWC. It was concluded that the application of free choice feeding of whole grains of maize and wheat plus concentrate feed increased the body weight of 28-d-old pigeon squabs and decreased the feed conversion rate of parent pigeons. This feeding strategy could be commercially interesting in meat-type pigeon production.

  2. Extinction-Optimized Volume Illumination.

    Science.gov (United States)

    Ament, Marco; Zirr, Tobias; Dachsbacher, Carsten

    2016-05-16

    We present a novel method to optimize the attenuation of light for the single scattering model in direct volume rendering. A common problem of single scattering is the high dynamic range between lit and shadowed regions due to the exponential attenuation of light along a ray. Moreover, light is often attenuated too strong between a sample point and the camera, hampering the visibility of important features. Our algorithm employs an importance function to selectively illuminate important structures and make them visible from the camera. With the importance function, more light can be transmitted to the features of interest, while contextual structures cast shadows which provide visual cues for perception of depth. At the same time, more scattered light is transmitted from the sample point to the camera to improve the primary visibility of important features. We formulate a minimization problem that automatically determines the extinction along a view or shadow ray to obtain a good balance between sufficient transmittance and attenuation. In contrast to previous approaches, we do not require a computationally expensive solution of a global optimization, but instead provide a closed-form solution for each sampled extinction value along a view or shadow ray and thus achieve interactive performance.

  3. Phylogenetic Clustering of Origination and Extinction across the Late Ordovician Mass Extinction.

    Directory of Open Access Journals (Sweden)

    Andrew Z Krug

    Full Text Available Mass extinctions can have dramatic effects on the trajectory of life, but in some cases the effects can be relatively small even when extinction rates are high. For example, the Late Ordovician mass extinction is the second most severe in terms of the proportion of genera eliminated, yet is noted for the lack of ecological consequences and shifts in clade dominance. By comparison, the end-Cretaceous mass extinction was less severe but eliminated several major clades while some rare surviving clades diversified in the Paleogene. This disconnect may be better understood by incorporating the phylogenetic relatedness of taxa into studies of mass extinctions, as the factors driving extinction and recovery are thought to be phylogenetically conserved and should therefore promote both origination and extinction of closely related taxa. Here, we test whether there was phylogenetic selectivity in extinction and origination using brachiopod genera from the Middle Ordovician through the Devonian. Using an index of taxonomic clustering (RCL as a proxy for phylogenetic clustering, we find that A both extinctions and originations shift from taxonomically random or weakly clustered within families in the Ordovician to strongly clustered in the Silurian and Devonian, beginning with the recovery following the Late Ordovician mass extinction, and B the Late Ordovician mass extinction was itself only weakly clustered. Both results stand in stark contrast to Cretaceous-Cenozoic bivalves, which showed significant levels of taxonomic clustering of extinctions in the Cretaceous, including strong clustering in the mass extinction, but taxonomically random extinctions in the Cenozoic. The contrasting patterns between the Late Ordovician and end-Cretaceous events suggest a complex relationship between the phylogenetic selectivity of mass extinctions and the long-term phylogenetic signal in origination and extinction patterns.

  4. Selectivity of terrestrial gastropod extinctions on an oceanic archipelago and insights into the anthropogenic extinction process

    OpenAIRE

    Chiba, Satoshi; Roy, Kaustuv

    2011-01-01

    Anthropogenic impacts have led to widespread extinctions of species on oceanic islands but the nature of many of these extinctions remains poorly known. Here we investigate extinction selectivities of terrestrial gastropods from the Ogasawara archipelago in the northwest Pacific, where anthropogenic threats have changed over time, shifting primarily from the effects of habitat loss to predation by a variety of different predators. Across all of the islands, extinct species had significantly s...

  5. 49 CFR 536.9 - Use of credits with regard to the domestically manufactured passenger automobile minimum standard.

    Science.gov (United States)

    2010-10-01

    ... manufactured passenger automobile minimum standard. 536.9 Section 536.9 Transportation Other Regulations... domestically manufactured passenger automobile minimum standard. (a) Each manufacturer is responsible for..., the domestically manufactured passenger automobile compliance category credit excess or shortfall...

  6. Timing of extinction relative to acquisition: A parametric analysis of fear extinction in humans

    NARCIS (Netherlands)

    Norrholm, S.D.; Vervliet, B.; Jovanovic, T.; Boshoven, W.; Myers, K.M.; Davis, M.; Rothbaum, B.O.; Duncan, E.J.

    2008-01-01

    Fear extinction is a reduction in conditioned fear following repeated exposure to the feared cue in the absence of any aversive event. Extinguished fear often reappears after extinction through spontaneous recovery. Animal studies suggest that spontaneous recovery can be abolished if extinction occu

  7. Constraints on Enhanced Extinction Resulting from Extinction Treatment in the Presence of an Added Excitor

    Science.gov (United States)

    Urcelay, Gonzalo P.; Lipatova, Olga; Miller, Ralph R.

    2009-01-01

    Three Pavlovian fear conditioning experiments with rats as subjects explored the effect of extinction in the presence of a concurrent excitor. Our aim was to explore this particular treatment, documented in previous studies to deepen extinction, with novel control groups to shed light on the processes involved in extinction. Relative to subjects…

  8. Safety climate and safety behavior in the passenger ferry context.

    Science.gov (United States)

    Lu, Chin-Shan; Yang, Chung-Shan

    2011-01-01

    This research empirically evaluates safety climate and safety behavior in the passenger ferry context. Using survey data collected from 155 respondents working for passenger ferry companies in Taiwan, hierarchical regression analysis was used to examine the effects of safety climate on self-reported safety behaviors. Confirmatory factor analysis identified five main dimensions of safety climate as measured on a passenger ferry safety climate scale: safety policy, safety motivation, emergency preparedness, safety training, and safety communication. Further, safety training and emergency preparedness were found to positively affect self-reported safety behaviors with respect to safety compliance and safety participation. The study also revealed positive associations among respondents' age, ferry capacity, and safety compliance. Implications of the study findings for increasing safety in ferry operations and their contribution to the development of safety management are discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Dynamics of Air Passenger Transportation in Eastern Romania

    Directory of Open Access Journals (Sweden)

    Dan Păuna

    2013-10-01

    Full Text Available The concept of an air route mile is, of course, entirely different from that of a road or rail route mile. An air route is a direct service between two cities. The too-rapid development of the air route system must inevitably result in an average intensity of operations on the route, and this means the frequencies are low or high, or the airplanes used are profitable or unprofitable. The purpose of this paper is to emphasize air passenger dynamics in Romania and to calculate specific indicators regarding this calculation for the airports in eastern Romania in 2011t., this, because the air passenger featurea indicator passenger – kilometer, starting with 2009 no longer calculate for aviation and shipping.

  10. Dynamic Pricing for Airline Revenue Management under Passenger Mental Accounting

    Directory of Open Access Journals (Sweden)

    Yusheng Hu

    2015-01-01

    Full Text Available Mental accounting is a far-reaching concept, which is often used to explain various kinds of irrational behaviors in human decision making process. This paper investigates dynamic pricing problems for single-flight and multiple flights settings, respectively, where passengers may be affected by mental accounting. We analyze dynamic pricing problems by means of the dynamic programming method and obtain the optimal pricing strategies. Further, we analytically show that the passenger mental accounting depth has a positive effect on the flight’s expected revenue for the single flight and numerically illustrate that the passenger mental accounting depth has a positive effect on the optimal prices for the multiple flights.

  11. Host cytokine responses of pigeons infected with highly pathogenic Thai avian influenza viruses of subtype H5N1 isolated from wild birds.

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Hayashi

    Full Text Available Highly pathogenic avian influenza virus (HPAIV of the H5N1 subtype has been reported to infect pigeons asymptomatically or induce mild symptoms. However, host immune responses of pigeons inoculated with HPAIVs have not been well documented. To assess host responses of pigeons against HPAIV infection, we compared lethality, viral distribution and mRNA expression of immune related genes of pigeons infected with two HPAIVs (A/Pigeon/Thailand/VSMU-7-NPT/2004; Pigeon04 and A/Tree sparrow/Ratchaburi/VSMU-16-RBR/2005; T.sparrow05 isolated from wild birds in Thailand. The survival experiment showed that 25% of pigeons died within 2 weeks after the inoculation of two HPAIVs or medium only, suggesting that these viruses did not cause lethal infection in pigeons. Pigeon04 replicated in the lungs more efficiently than T.sparrow05 and spread to multiple extrapulmonary organs such as the brain, spleen, liver, kidney and rectum on days 2, 5 and 9 post infection. No severe lesion was observed in the lungs infected with Pigeon04 as well as T.sparrow05 throughout the collection periods. Encephalitis was occasionally observed in Pigeon04- or T.sparrow05-infected brain, the severity, however was mostly mild. To analyze the expression of immune-related genes in the infected pigeons, we established a quantitative real-time PCR analysis for 14 genes of pigeons. On day 2 post infection, Pigeon04 induced mRNA expression of Mx1, PKR and OAS to a greater extent than T.sparrow05 in the lungs, however their expressions were not up-regulated concomitantly on day 5 post infection when the peak viral replication was observed. Expressions of TLR3, IFNα, IL6, IL8 and CCL5 in the lungs following infection with the two HPAIVs were low. In sum, Pigeon04 exhibited efficient replication in the lungs compared to T.sparrow05, but did not induce excessive host cytokine expressions. Our study has provided the first insight into host immune responses of pigeons against HPAIV infection.

  12. Passenger Perspectives in Railway Timetabling: A Literature Review

    DEFF Research Database (Denmark)

    Jensen, Jens Parbo; Nielsen, Otto Anker; Prato, Carlo Giacomo

    2016-01-01

    their emphasis on passengers to the consideration of transfer maintenance. Clearly, passengers’ travel behaviour is far more complex and multi-faceted and thus several other aspects should be considered, as becoming more and more evident from passenger surveys. The current literature review starts by looking...... at the parameters that railway optimisation/planning studies are focused on and the key performance indicators that impact railway planning. The attention then turns to the parameters influencing passengers’ perceptions and travel experiences. Finally, the review proposes guidelines on how to reduce the gap between...

  13. Estimating passenger numbers in trains using existing weighing capabilities

    DEFF Research Database (Denmark)

    Nielsen, Bo Friis; Frølich, Laura; Nielsen, Otto Anker

    2013-01-01

    in estimates of total numbers of passengers propagate along train runs. Counting errors in manual and electronic counting systems are typically flow-dependent, making uncertainty a function of volume. This paper presents a new counting technique that exploits the weighing systems installed in most modern...... trains to control braking. This technique makes passenger counting cheaper and ensures a complete sample. The paper compares numbers estimated by this technique with manual counts and counts from an infrared system in trains in urban Copenhagen. It shows that the weighing system provides more accurate...

  14. Real-Time Mass Passenger Transport Network Optimization Problems

    OpenAIRE

    2005-01-01

    The aim of Real-Time Mass Transport Vehicle Routing Problem (MTVRP) is to find a solution to route n vehicles in real time to pick up and deliver m passengers. This problem is described in the context of flexible large-scale mass transportation options that use new technologies for communication among passengers and vehicles. The solution of such a problem is relevant to future transportation options involving large scale real-time routing of shared-ride fleet transit vehicles. However, the g...

  15. 75 FR 16564 - High-Speed Intercity Passenger Rail (HSIPR) Program

    Science.gov (United States)

    2010-04-01

    ... intercity passenger rail ridership growth. In the FY 2010 DOT Appropriations Act, Congress built upon the..., maintenance of equipment, transportation (train movement), passenger traffic and services (marketing... corridor program to promote economic development, including contributions to a sustainable...

  16. 75 FR 22675 - Notice of Passenger Facility Charge (PFC) Approvals and Disapprovals

    Science.gov (United States)

    2010-04-29

    .... Terminal restroom design. Terminal restroom remodel. Terminal elevator upgrades. Terminal flight... passenger loading bridge. PFC consultation. Passenger terminal remodeling. Pavement management system.... Rehabilitation of taxilane K-1. Design and implement noise mitigation measures. Brief Description of...

  17. 78 FR 76382 - Notice of Passenger Facility Charge (PFC) Approvals and Disapprovals

    Science.gov (United States)

    2013-12-17

    ... firefighting personnel. Acquire Americans with Disabilities Act passenger boarding ramp. Install common use flight information system. DECISION DATE: May 13, 2013. FOR FURTHER INFORMATION CONTACT: Neil Kumar, San... Federal Aviation Administration Notice of Passenger Facility Charge (PFC) Approvals and Disapprovals...

  18. 78 FR 73876 - Agency Information Collection Activities: Passenger and Crew Manifest

    Science.gov (United States)

    2013-12-09

    ... about passengers and crew onboard inbound and outbound international flights before their arrival in or... Total Annual Burden Hours: 307,245. Estimated Costs: $68,361,719. Commercial Airline Passengers...

  19. Long-Term Maintenance of Immediate or Delayed Extinction Is Determined by the Extinction-Test Interval

    Science.gov (United States)

    Johnson, Justin S.; Escobar, Martha; Kimble, Whitney L.

    2010-01-01

    Short acquisition-extinction intervals (immediate extinction) can lead to either more or less spontaneous recovery than long acquisition-extinction intervals (delayed extinction). Using rat subjects, we observed less spontaneous recovery following immediate than delayed extinction (Experiment 1). However, this was the case only if a relatively…

  20. Extinction-Induced Variability in Human Behavior

    Science.gov (United States)

    Kinloch, Jennifer M.; Foster, T. Mary; McEwan, James S. A.

    2009-01-01

    Participants earned points by pressing a computer space bar (Experiment 1) or forming rectangles on the screen with the mouse (Experiment 2) under differential-reinforcement-of-low-rate schedules, followed by extinction. Variability in interresponse time (the contingent dimension) increased during extinction, as for Morgan and Lee (1996);…

  1. Periodicity of extinction: A 1988 update

    Science.gov (United States)

    Sepkowski, J. John, Jr.

    1988-01-01

    The hypothesis that events of mass extinction recur periodically at approximately 26 my intervals is an empirical claim based on analysis of data from the fossil record. The hypothesis has become closely linked with catastrophism because several events in the periodic series are associated with evidence of extraterrestrial impacts, and terrestrial forcing mechanisms with long, periodic recurrences are not easily conceived. Astronomical mechanisms that have been hypothesized include undetected solar companions and solar oscillation about the galactic plane, which induce comet showers and result in impacts on Earth at regular intervals. Because these mechanisms are speculative, they have been the subject of considerable controversy, as has the hypothesis of periodicity of extinction. In response to criticisms and uncertainties, a data base was developed on times of extinction of marine animal genera. A time series is given and analyzed with 49 sample points for the per-genus extinction rate from the Late Permian to the Recent. An unexpected pattern in the data is the uniformity of magnitude of many of the periodic extinction events. Observations suggest that the sequence of extinction events might be the result of two sets of mechanisms: a periodic forcing that normally induces only moderate amounts of extinction, and independent incidents or catastrophes that, when coincident with the periodic forcing, amplify its signal and produce major-mass extinctions.

  2. Can Parallelingualism Save Norwegian from Extinction?

    Science.gov (United States)

    Linn, Andrew R.

    2010-01-01

    Language extinction is one of the most pressing issues in linguistics today, and the literature is full of discussion about how to combat it. Statements that Norwegian is amongst the languages that are already extinct are merely examples of a widespread tendency in the literature towards erroneous information about Norwegian. Nonetheless, there is…

  3. Current extinction rates of reptiles and amphibians.

    Science.gov (United States)

    Alroy, John

    2015-10-20

    There is broad concern that a mass extinction of amphibians and reptiles is now underway. Here I apply an extremely conservative Bayesian method to estimate the number of recent amphibian and squamate extinctions in nine important tropical and subtropical regions. The data stem from a combination of museum collection databases and published site surveys. The method computes an extinction probability for each species by considering its sighting frequency and last sighting date. It infers hardly any extinction when collection dates are randomized and it provides underestimates when artificial extinction events are imposed. The method also appears to be insensitive to trends in sampling; therefore, the counts it provides are absolute minimums. Extinctions or severe population crashes have accumulated steadily since the 1970s and 1980s, and at least 3.1% of frog species have already disappeared. Based on these data and this conservative method, the best estimate of the global grand total is roughly 200 extinctions. Consistent with previous results, frog losses are heavy in Latin America, which has been greatly affected by the pathogenic chytrid fungus Batrachochytrium dendrobatidis. Extinction rates are now four orders-of-magnitude higher than background, and at least another 6.9% of all frog species may be lost within the next century, even if there is no acceleration in the growth of environmental threats.

  4. Synchronous extinction of North America's Pleistocene mammals

    Science.gov (United States)

    Faith, J. Tyler; Surovell, Todd A.

    2009-12-01

    The late Pleistocene witnessed the extinction of 35 genera of North American mammals. The last appearance dates of 16 of these genera securely fall between 12,000 and 10,000 radiocarbon years ago (≈13,800-11,400 calendar years B.P.), although whether the absence of fossil occurrences for the remaining 19 genera from this time interval is the result of sampling error or temporally staggered extinctions is unclear. Analysis of the chronology of extinctions suggests that sampling error can explain the absence of terminal Pleistocene last appearance dates for the remaining 19 genera. The extinction chronology of North American Pleistocene mammals therefore can be characterized as a synchronous event that took place 12,000-10,000 radiocarbon years B.P. Results favor an extinction mechanism that is capable of wiping out up to 35 genera across a continent in a geologic instant.

  5. Mass extinction in poorly known taxa.

    Science.gov (United States)

    Régnier, Claire; Achaz, Guillaume; Lambert, Amaury; Cowie, Robert H; Bouchet, Philippe; Fontaine, Benoît

    2015-06-23

    Since the 1980s, many have suggested we are in the midst of a massive extinction crisis, yet only 799 (0.04%) of the 1.9 million known recent species are recorded as extinct, questioning the reality of the crisis. This low figure is due to the fact that the status of very few invertebrates, which represent the bulk of biodiversity, have been evaluated. Here we show, based on extrapolation from a random sample of land snail species via two independent approaches, that we may already have lost 7% (130,000 extinctions) of the species on Earth. However, this loss is masked by the emphasis on terrestrial vertebrates, the target of most conservation actions. Projections of species extinction rates are controversial because invertebrates are essentially excluded from these scenarios. Invertebrates can and must be assessed if we are to obtain a more realistic picture of the sixth extinction crisis.

  6. External fixation to correct tarsal-metatarsal fracture in rock pigeon (Columba livia

    Directory of Open Access Journals (Sweden)

    Leandro Almeida Rui

    Full Text Available ABSTRACT Orthopedic conditions, such as bone fractures, are very common in avian medicine. External fixators have been considered the gold standard for birds, since they allow early movement of the limbs and minimal invasive surgery. Fractures in several bones have been successfully treated in pigeons. However, to the best of our knowledge, this case represents the first report of successful surgical repair of tarsal-metatarsal fracture in rock pigeon. External fixator was made with four 24G catheters, being inserted manually proximal and distal to the fracture and connected with polymerizable acrylic. Radiographic consolidation of fracture was observed 60 days post-surgery and anti-inflammatory and antibiotic protocols were successful on avoiding pain and infection during surgery and bone healing.

  7. Genomic diversity and evolution of the head crest in the rock pigeon

    Science.gov (United States)

    Shapiro, Michael D.; Kronenberg, Zev; Li, Cai; Domyan, Eric T.; Pan, Hailin; Campbell, Michael; Tan, Hao; Huff, Chad D.; Hu, Haofu; Vickrey, Anna I.; Nielsen, Sandra C.A.; Stringham, Sydney A.; Hu, Hao; Willerslev, Eske; Gilbert, M. Thomas P.; Yandell, Mark; Zhang, Guojie; Wang, Jun

    2013-01-01

    The geographic origins of breeds and genetic basis of variation within the widely distributed and phenotypically diverse domestic rock pigeon (Columba livia) remain largely unknown. We generated a rock pigeon reference genome and additional genome sequences representing domestic and feral populations. We find evidence for the origins of major breed groups in the Middle East, and contributions from a racing breed to North American feral populations. We identify EphB2 as a strong candidate for the derived head crest phenotype shared by numerous breeds, an important trait in mate selection in many avian species. We also find evidence that this trait evolved just once and spread throughout the species, and that the crest originates early in development by the localized molecular reversal of feather bud polarity. PMID:23371554

  8. Gravity anomalies without geomagnetic disturbances interfere with pigeon homing--a GPS tracking study.

    Science.gov (United States)

    Blaser, Nicole; Guskov, Sergei I; Entin, Vladimir A; Wolfer, David P; Kanevskyi, Valeryi A; Lipp, Hans-Peter

    2014-11-15

    The gravity vector theory postulates that birds determine their position to set a home course by comparing the memorized gravity vector at the home loft with the local gravity vector at the release site, and that they should adjust their flight course to the gravity anomalies encountered. As gravity anomalies are often intermingled with geomagnetic anomalies, we released experienced pigeons from the center of a strong circular gravity anomaly (25 km diameter) not associated with magnetic anomalies and from a geophysical control site, equidistant from the home loft (91 km). After crossing the border zone of the anomaly--expected to be most critical for pigeon navigation--they dispersed significantly more than control birds, except for those having met a gravity anomaly en route. These data increase the credibility of the gravity vector hypothesis. © 2014. Published by The Company of Biologists Ltd.

  9. The reduction of heat production in exercising pigeons after L-carnitine supplementation.

    Science.gov (United States)

    Janssens, G P; Buyse, J; Seynaeve, M; Decuypere, E; De Wilde, R

    1998-04-01

    Four groups (CS,CR,PS,PR) of nine trained male racing pigeons were deprived of feed for 1 d and then subjected to a respiration chamber test in order to study the effect of oral 1-carnitine supplementation on the energy metabolism during flight. One week before, groups CS and CR were orally supplemented with 90 mg of 1-carnitine daily, whereas PS and PR were given a placebo. Groups CS and PS underwent flight simulation by electrostimulation of the breast muscles. Flight simulation increased heat production, kept respiratory quotient from decreasing, decreased thyroxine levels, and increased weight loss. L-Carnitine decreased the rise in heat production during electrostimulation but did not influence respiratory quotient, weight loss, or thyroid hormones. L-Carnitine supplementation in pigeons improves fatty acid combustion efficiency during heavy exercise.

  10. Enhanced specific antibody response to bovine serum albumin in pigeons due to L-carnitine supplementation.

    Science.gov (United States)

    Janssens, G P; Mast, J; Goddeeris, B M; Cox, E; Hesta, M; De Wilde, R O

    2000-09-01

    1. Thirty adult female pigeons (Columba livia domestica) were randomly divided into 3 equal groups; the 1st and 2nd groups were immunised with bovine serum albumin (BSA) at 0 and 20 d, the 2nd group also received 1 g L-carnitine per litre of drinking water from -5 to 25 d post-immunisation (dpi) and the 3rd group, a control group, received neither treatment. 2. Body weights and serum samples were taken at 0, 5, 10, 15, 20, 25, 30 and 35 dpi. 3. Both BSA-specific IgG and IgM responses were enhanced by about 10% by L-carnitine supplementation. 4. L-carnitine supplemented pigeons showed a higher water consumption. Body weight loss during the onset of the immune response showed a slight tendency to be counteracted by L-carnitine supplementation. 5. The impact of L-carnitine on resistance and resilience to an immunological challenge is discussed.

  11. Frequency of endophytic fungi isolated from Dendrobium crumenatum (Pigeon orchid and antimicrobial activity

    Directory of Open Access Journals (Sweden)

    WIBOWO MANGUNWARDOYO

    2012-01-01

    Full Text Available Mangunwardoyo W, Suciatmih, Gandjar I. 2012. Frequency of endophytic fungi isolated from Dendrobium crumenatum (Pigeon orchid and antimicrobial activity. Biodiversitas 13: 34-39. The aims of this research was to isolate and study the frequency of endophytic fungi from roots, bulbous, stems, and leaves of Dendrobium crumenatum Sw. (pigeon orchid collected from Tanah Baru housing area, Bogor Botanical Garden, and Herbarium Bogoriense; and to assess for antimicrobial activity against Candida albicans ATCC 2091, Candida tropicalis LIPIMC 203, Escherichia coli ATCC 25922, Bacillus subtilis ATCC 6633 and Staphylococcus aureus ATCC 25923. Twelve species of endophytic fungi were identified from 60 samples obtained from D. crumenatum. Guignardia endophyllicola (anamorph: Phyllosticta capitalensis were the dominant endophytic fungi. Screening of the anti-microorganism activity of the endophytic fungi revealed that Fusarium nivale inhibited C albicans and C. tropicalis. All specimens did not inhibit B. subtilis, E. coli, and S. aureus.

  12. Characterization of Pigeon Paramyxoviruses (Newcastle disease virus) Isolated in Kazakhstan in 2005

    Institute of Scientific and Technical Information of China (English)

    Andrey Bogoyavlenskiy; Vladimir Berezin; Alexey Prilipov; Eugeniy Usachev; Ilya Korotetskiy; Irina Zaitceva; Aydyn Kydyrmanov; Marat Sayatov

    2012-01-01

    Isolates of Newcastle disease virus (NDV) from deceased wild and domestic pigeons in Kazakhstan were obtained from the Almaty region during 2005 and were genotypically analyzed by using reverse transcription polymerase chain reaction (RT-PCR) with primers specific to the viral fusion (F) protein gene.Part of the amplified F protein DNA product (nucleotide sequence 47-422) and the deduced amino acid sequenceswere compared phylogenetically with those from strains previously reported in other geographic regions.Phylogenetic analysis indicated that the Kazakhstanian pigeon paramyxovirus type 1 (PPMV-1) isolates belong to genotype Ⅵ or 4bii.To our knowledge,this is the first reported Ⅵ isolates that possess the sequences of 112 GKRQKR116* F117 within the F0 protein.The information is fundamental to improving the efficiency of control strategies and vaccine development for NDV.

  13. Histopathological changes in the upper digestive tract of pigeons infected with Hadjelia truncata.

    Science.gov (United States)

    Oryan, Ahmad; Rakhshandehroo, Ehsan; Kamali, S Amir; Taebi Pour, Mohammad Jafar

    2016-09-01

    Thirty-five pigeons from ten different farms in Fars area, southern Iran were submitted for post mortem inspection. Based on the clinical observations and gross pathological examinations, all the birds showed severe weight loss, diarrhea and to some extent ventricular enlargement. Furthermore, all the cases demonstrated large numbers of nematodes attached to the mucosa and submucosa of the ventriculus. Parasitological examinations revealed that the recovered parasites were Hadjelia truncata. The histopathological changes showed necrosis of the mucosal cells with moderate infiltration of lymphocytes, macrophages, heterophils and eosinophils in the lamina properia and muscularis mucosa in the infected animals. Based on the parasitological and pathological findings it can be concluded that the nematode H. truncate could be assigned as a pathogenic agent in the upper tract of pigeons.

  14. Bárány's theory is right, but incomplete. An experimental study in pigeons.

    Science.gov (United States)

    Wit, H P; Spoelstra, H A; Segenhout, J M

    1990-01-01

    The horizontal semicircular canal in pigeons was thermally stimulated with a miniature Peltier-element device. Sound evoked electric responses from the vestibular organ were modulated by the caloric stimulus. Experiments were performed under minimal influence of gravity, (horizontal canals in horizontal plane), and with the pigeons head tilted forwards or backwards. On the basis of the results it was concluded that the influence of gravity can be described by Bárány's convection theory. Extra effects are, however, present and they are most probably partly of mechanical origin (fluid expansion) and partly due to a direct influence of temperature on the vestibular receptors. Further experiments are needed to investigate the origin of these extra effects in more detail.

  15. Avian pox in white-tailed laurel-pigeons from the Canary Islands.

    Science.gov (United States)

    Manuel Medina, Félix; Adolfo Ramírez, Gustavo; Hernández, Antonio

    2004-04-01

    Two diseased young white-tailed laurel-pigeons (Columba junoniae), an endemic and endangered species of the Canary Islands (Spain), were found in La Palma. They were very depressed and had severe cutaneous yellowish nodular lesions in feathered and unfeathered areas on the bodies of both birds. Necropsy and histopathologic analyses were conducted. The presence of epidermal hypertrophy and hyperplasia in cutaneous lesions, as well as several acidophilic intracytoplasmic inclusions in affected epithelial cells (Bollinger bodies), confirmed avian poxvirus infection. This is the first report of avian pox in whitetailed laurel-pigeons or in any other free-ranging bird in the Canaries, and it might indicate that other threatened birds of the Canarian Archipelago may be affected by this viral disease.

  16. Group decisions and individual differences: route fidelity predicts flight leadership in homing pigeons (Columba livia).

    Science.gov (United States)

    Freeman, Robin; Mann, Richard; Guilford, Tim; Biro, Dora

    2011-02-23

    How social-living animals make collective decisions is currently the subject of intense scientific interest, with increasing focus on the role of individual variation within the group. Previously, we demonstrated that during paired flight in homing pigeons, a fully transitive leadership hierarchy emerges as birds are forced to choose between their own and their partner's habitual routes. This stable hierarchy suggests a role for individual differences mediating leadership decisions within homing pigeon pairs. What these differences are, however, has remained elusive. Using novel quantitative techniques to analyse habitual route structure, we show here that leadership can be predicted from prior route-following fidelity. Birds that are more faithful to their own route when homing alone are more likely to emerge as leaders when homing socially. We discuss how this fidelity may relate to the leadership phenomenon, and propose that leadership may emerge from the interplay between individual route confidence and the dynamics of paired flight.

  17. Potential of Pigeon Creek, San Salvador, Bahamas, as Nursery Habitat for Juvenile Reef Fish

    Directory of Open Access Journals (Sweden)

    Conboy, Ian Christopher

    2011-10-01

    Full Text Available This project assessed the significance of Pigeon Creek, San Salvador, Bahamas as a nursery habitat for coral reef fishes. Pigeon Creek’s perimeter is lined with mangrove and limestone bedrock. The bottom is sand or seagrass and ranges in depth from exposed at low tide to a 3-m deep, tide-scoured channel. In June 2006 and January 2007, fish were counted and their maturity was recorded while sampling 112 of 309 possible 50-m transects along the perimeter of the Pigeon Creek. Excluding silversides (Atherinidae, 52% of fish counted, six families each comprised >1% of the total abundance (Scaridae/parrotfishes, 35.3%; Lutjanidae/snappers, 23.9%; Haemulidae/grunts, 21.0%; Gerreidae/mojarras, 8.5%; Pomacentridae/damselfishes, 6.1%; Labridae/wrasses, 2.4%. There were few differences in effort-adjusted counts among habitats (mangrove, bedrock, mixed, sections (north, middle, southwest and seasons (summer 2006 and winter 2007. Red Mangrove (Rhizophora mangle, covering 68% of the perimeter was where 62% of the fish were counted. Snappers, grunts and parrotfishes are important food fishes and significant families in terms of reef ecology around San Salvador. Mangrove was the most important habitat for snappers and grunts; bedrock was most important for parrotfishes. The southwest section was important for snappers, grunts and parrotfishes, the north section for grunts and parrotfishes, and the middle section for snappers. Among the non-silverside fish counted, 91.2% were juveniles. These results suggest that Pigeon Creek is an important nursery for the coral reefs surrounding San Salvador and should be protected from potential disturbances.

  18. Variance in prey abundance influences time budgets of breeding seabirds: Evidence from pigeon guillemots Cepphus columba

    Science.gov (United States)

    Litzow, Michael A.; Piatt, J.F.

    2003-01-01

    We use data on pigeon guillemots Cepphus columba to test the hypothesis that discretionary time in breeding seabirds is correlated with variance in prey abundance. We measured the amount of time that guillemots spent at the colony before delivering fish to chicks ("resting time") in relation to fish abundance as measured by beach seines and bottom trawls. Radio telemetry showed that resting time was inversely correlated with time spent diving for fish during foraging trips (r = -0.95). Pigeon guillemots fed their chicks either Pacific sand lance Ammodytes hexapterus, a schooling midwater fish, which exhibited high interannual variance in abundance (CV = 181%), or a variety of non-schooling demersal fishes, which were less variable in abundance (average CV = 111%). Average resting times were 46% higher at colonies where schooling prey dominated the diet. Individuals at these colonies reduced resting times 32% during years of low food abundance, but did not reduce meal delivery rates. In contrast, individuals feeding on non-schooling fishes did not reduce resting times during low food years, but did reduce meal delivery rates by 27%. Interannual variance in resting times was greater for the schooling group than for the non-schooling group. We conclude from these differences that time allocation in pigeon guillemots is more flexible when variable schooling prey dominate diets. Resting times were also 27% lower for individuals feeding two-chick rather than one-chick broods. The combined effects of diet and brood size on adult time budgets may help to explain higher rates of brood reduction for pigeon guillemot chicks fed non-schooling fishes.

  19. [The influence of experimental hemispherectomy and hemicerebellectomy on the acquisition and retention of habituation in pigeon].

    Science.gov (United States)

    Kaźmierczak, H

    1995-01-01

    The subject of investigation was the analysis of the acquisition and retention of the vestibular habituation in pigeons after hemispherectomy or hemicerebellectomy. The habituation training was performed using rotatory test. The frequency of head nystagmus and postural reflexes were examined before and after acquisition of habituation and some days later, for evaluation of retention. Our results suggests that hemispherectomy does not inhibit acquisition of habituation but retention of this phenomenon is shorter at that time. The hemicerebellectomy makes impossible the vestibular habituation.

  20. Pigeons (Columba livia) as Trainable Observers of Pathology and Radiology Breast Cancer Images

    Science.gov (United States)

    Levenson, Richard M.; Krupinski, Elizabeth A.; Navarro, Victor M.; Wasserman, Edward A.

    2015-01-01

    Pathologists and radiologists spend years acquiring and refining their medically essential visual skills, so it is of considerable interest to understand how this process actually unfolds and what image features and properties are critical for accurate diagnostic performance. Key insights into human behavioral tasks can often be obtained by using appropriate animal models. We report here that pigeons (Columba livia)—which share many visual system properties with humans—can serve as promising surrogate observers of medical images, a capability not previously documented. The birds proved to have a remarkable ability to distinguish benign from malignant human breast histopathology after training with differential food reinforcement; even more importantly, the pigeons were able to generalize what they had learned when confronted with novel image sets. The birds’ histological accuracy, like that of humans, was modestly affected by the presence or absence of color as well as by degrees of image compression, but these impacts could be ameliorated with further training. Turning to radiology, the birds proved to be similarly capable of detecting cancer-relevant microcalcifications on mammogram images. However, when given a different (and for humans quite difficult) task—namely, classification of suspicious mammographic densities (masses)—the pigeons proved to be capable only of image memorization and were unable to successfully generalize when shown novel examples. The birds’ successes and difficulties suggest that pigeons are well-suited to help us better understand human medical image perception, and may also prove useful in performance assessment and development of medical imaging hardware, image processing, and image analysis tools. PMID:26581091