64 research outputs found

    Sex differences in feeding visit rates in Northern Wheatears Oenanthe oenanthe

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    Abstract The Northern Wheatear (Oenanthe oenanthe) is a small insectivorous passerine bird living in open landscapes. Both parents feed the brood of approximately five chicks, but little is known about how each sex allocates their feeding effort. In this study I investigate feeding nest visit differences between male and female Northern Wheatears relative to the age of the chicks, the number of chicks and the quality of the territory for 17 pairs from 2008-2010. Data were collected using automated data loggers to record nest visitation rates during chick feeding, and the sex was determined from nest video cameras. I also examine if the parents’ rate of feeding visits changes over the nestling period. The predictions were that: (1) the male would visit relatively more when the chicks were young compared to the female, and that these roles would reverse (i.e. the female would become the parent with most feeding visits) when the chicks grew older; (2) any differences between the feeding rates of parents would be smaller for larger broods; (3) any differences between the feeding rates of parents would be relatively small when the quality of the territory was low; and (4) parents would increase their rate of feeding visits as the chicks grew. The predictions are based on the theory of resource limitation. I found some support for differences in feeding nest visits between the sexes. The male had a greater share of feeding visits when the chicks were young and a smaller share when the chicks were older. There was no difference between the male and the female in their feeding visit rates with varying numbers of young. The quality of the territory had a small effect on the sexes’ feeding visits, but only when the age of the chicks was added to the analysis. The rate of feeding visits was higher when the chicks were older. This study is the first to provide information on wheatear behaviour in the nest relative to its sex and should outline the basis of future research on sex differences in the Northern Wheatear.Sammanfattning StenskvĂ€ttan (Oenanthe oenanthe) Ă€r en liten insektsĂ€tande tĂ€tting som lever i öppna landskap. BĂ„da förĂ€ldrar matar kullen pĂ„ ca fem ungar, men kunskapen om hur könen fördelar sina anstrĂ€ngningar Ă€r liten. I den hĂ€r studien undersöker jag skillnader i matningsfrekvens mellan hane och hona av stenskvĂ€tta i förhĂ„llande till ungarnas Ă„lder, deras antal och kvaliteten pĂ„ reviret hos 17 par under 2008 till 2010. Data samlades in med en automatiserad datalogger för att registrera bobesöksfrekvens medan ungarna matas, och den matande förĂ€lderns kön bestĂ€mdes frĂ„n filmer av boet. Jag undersökte ocksĂ„ om förĂ€ldrarnas matningsfrekvens Ă€ndras under tiden ungarna Ă€r i boet. Jag antog att: (1) hanen skulle mata oftare relativt honan nĂ€r ungarna Ă€r smĂ„, och att rollerna skulle bli ombytta (d.v.s. honan skulle bli förĂ€ldern med högst matningsfrekvens) nĂ€r ungarna blivit Ă€ldre; (2) skillnader i matningsfrekvens mellan förĂ€ldrarna skulle vara mindre ju fler ungar det Ă€r i boet; (3) skillnader i matningsfrekvens mellan förĂ€ldrarna skulle vara relativt liten nĂ€r kvaliteten pĂ„ reviret var lĂ„g; och (4) förĂ€ldrarna skulle öka matningsfrekvensen allteftersom ungarna vĂ€xte. Antagandena Ă€r baserade pĂ„ teorin om begrĂ€nsade resurser. Jag fann visst stöd för skillnader i matningsfrekvens mellan könen. Hanen hade en större del av matningen nĂ€r ungarna var smĂ„ men det var ingen skillnad nĂ€r ungarna var större. Det var ingen skillnad mellan hane och hona med varierande antal ungar. Kvaliteten pĂ„ reviret hade en liten effekt pĂ„ könens matningsfrekvens, men bara nĂ€r ungarnas Ă„lder togs med i analysen. Matningsfrekvensen var högre för Ă€ldre ungar Ă€n för yngre. Den hĂ€r studien Ă€r den första att förse information om hur stenskvĂ€ttor beter sig i boet i förhĂ„llande till dess kön och bör utgöra grunden för framtida forskning pĂ„ könsskillnader hos stenskvĂ€tta

    SmÄskalig utsÀdesproduktion

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    The economic situation in the Swedish agricultural industry is currently experiencing a development towards larger units. This progress occurs simultaneously as farmers in cooperation more frequently make investments to decrease risk exposure and to improve the financial result. The purpose with this thesis is to study which advantages and problems a group of farmers experience after a common investment in a small-scale seed production. The aim with this investment is to increase the level of vertical integration in their respective agricultural firms and the results will be analyzed from an economic point of view. At present, the farmers are all seed producers with considerable cultivation areas. They experience that the co it of inputs are getting higher and higher. Further refining the goods produced means that the farmers produce certified seed in a common plant, for own use and for sale. The thesis is based on interviews with six farmers. Three of them belong to the group "Refiners" and the other three are called "Buyers". Common for all six is that they all have good knowledge about seed industry and the problems involved in seed production. The study also aims to show what economic incentives that occur when farmers cooperate with each other when investing to increase the level of vertical integration, as well as analyze the problems that arise. The theoretical framework is based on the agent theory which describes problems in a common organizational structure. Problems considered are the decision-maker problem, portfolio problem, horizon problem and finally the control problem. The results obtained in the study show that large volumes are required to reach good profitability when producing certified seed. The price of seed and grain on the market also plays a key role for the final result. It is also important that the farmers have a good understanding of what the refining industry asks for. Furthermore, a good relationship to the customers is of importance to create a long-term profitability.Den ekonomiska situationen i det svenska lantbruket leder till en utveckling mot allt större enheter samtidigt som lantbrukare i samverkan ofta genomför investeringar för att minska riskexponeringen och förbĂ€ttra det ekonomiska resultatet. Denna studie avser att studera de ekonomiska fördelar och problem som en grupp lantbrukare möter dĂ„ de via en gemensam investering i smĂ„skalig utsĂ€desproduktion strĂ€var efter att öka graden av en vertikal integration i sina lantbruksföretag. I dagslĂ€get Ă€r de spannmĂ„lsodlare med betydande arealer som upplever att insatsvarorna blir en allt större kostnadspost. VidareförĂ€dlingen i deras fall innebĂ€r att lantbrukarna producerar certifierat utsĂ€de i en gemensam anlĂ€ggning för eget bruk och för försĂ€ljning. Studien grundar pĂ„ intervjuer med sex lantbrukare. Tre stycken av dem tillhör den grupp som i studien benĂ€mns ”förĂ€dlare” och de tre övriga benĂ€mns ”köpare”. Gemensamt för samtliga Ă€r att de har stor kunskap om spannmĂ„lsbranschen och goda insikter i problematiken kring produktionen av utsĂ€de. Studien har för avsikt att dels visa vilka ekonomiska incitament som uppstĂ„r dĂ„ lantbrukare samverkar via en investering i en vertikalt integreration, dels att analysera de olika problem som uppstĂ„r. Arbetets teoretiska referensram grundas pĂ„ agentteorin. Teorin beskriver de olika agentproblem som kan uppstĂ„ i en gemensam organisatorisk struktur. De problem som beaktas Ă€r beslutsfattarproblemet, portföljproblemet, horisontproblemet samt kontrollproblemet. Studien visar att det krĂ€vs stora volymer för att nĂ„ god lönsamhet vid produktionen av certifierat utsĂ€de. Dessutom Ă€r en god relation till kunderna vĂ€sentlig för att fĂ„ en lĂ„ngsiktig lönsamhet. Priset pĂ„ utsĂ€de och spannmĂ„l i handeln har stor betydelse för det ekonomiska resultatet. Det Ă€r Ă€ven vĂ€sentligt att lantbrukarna har en god uppfattning om vilka sorter förĂ€dlingsindustrin efterfrĂ„gar

    StyrelsesammansÀttning - och dess inverkan pÄ företagets prestation

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    Uppsatsens syfte Àr att söka klarlÀgga om olika styrelseutformning, med avseende pÄ sex bestÀmda faktorer, pÄverkar företagets prestation och om det gÄr att genom statistisk analys fastslÄ om dessa faktorer utgör en mÀtbar pÄverkan pÄ prestationen. Faktorererna utgörs av styrelsemedlemmarnas kön, genomsnittÄlder, andel utlÀndska ledamöter i styrelsen som pÄ ett direkt sett utgör oilka kategorier av styrelsemedlemmar. Dessutom har uppsatsen sett pÄ effekten av styrelsens storlek och ledamöternas eventuella beroende. Dessa faktorer har jÀmförts med ett prestationsmÄtt som utgjorts av företagets vÀrdeförÀndring pÄ börsen, korrigerat med respektive branschindex. JÀmförelsen har gjorts över fem Är, med hjÀlp av regressionsanalys. Resultatet ger vid handen att förhÄllandevis liten signifikans erhÄlls vid mÀtningarna. Det Àr sÄledes svÄrt att dra nÄgra lÄngtgÄende slutsatser angÄende en optimal styrelseutforming enligt undersökningen. Vissa slutsatser kan dras betrÀffande styrelsens storlek, vilket ligger vÀl i linje med tidigare forskning

    Differential actions of m and n cholinergic agonists on the brainstem activating system

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    The differential actions of i.v. arecoline and nicotine were determined on neocortical and limbic system EEG activation in acute rostral and caudal midbrain transected cats. All animals were prepared under diethyl ether anesthesia and after surgery, paralyzed with decamethonium and maintained on artificial respiration. The peripheral effects of these cholinergic agonists were reduced by methyl atropine (250 [mu]g/kg ) and/or trimethidinium (1 mg/kg) pretreatment.In the caudal midbrain transected preparation, nicotine (20-40 [mu]g/kg) induced marked EEG activation in both the neocortex and hippocampus. After bilateral lesions of the midbrain reticular formation in the same preparation, EEG activation was not observed with nicotine in doses up to 100 [mu]g/kg. The EEG effects of nicotine were blocked by atropine (1 mg/kg) and mecamylamine (1 mg/kg) but not trimethidinium (1 mg/kg). In the rostral midbrain transected preparation no EEG activation was noted with nicotine in doses up to 100 [mu]g/kg. Sporadic sharp waves appeared in the hippocampus with the larger doses indicating a convulsant site of action above the level of transection.Arecoline induced dissociation of the EEG in the hippocampus and neocortex in doses of 20-40 [mu]g/kg in the rostral midbrain transected cat. Marked hippocampal slow "arousal" waves with no desynchronization of the neocortical EEG were seen. These effects of arecoline were blocked by atropine. In the caudal midbrain preparation, even after bilateral lesions of the midbrain reticular formation which blocked nicotine activation, arecoline (20-40 [mu]g/kg) still induced hippocampal slow `arousal' waves without neocortical desynchronization. With doses of 100 [mu]g/kg of arecoline both neocortical and hippocampal EEG activation was noted.It is concluded that the site of nicotine on the rostral forebrain activating system is located primarily in the midbrain reticular formation, whereas arecoline acts on the midbrain reticular formation as well as above the level of the mesencephalon.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33004/1/0000388.pd

    Autonomous Path Following Using Convolutional Networks

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    Autonomous vehicles have many application possibilities within many different fields like rescue missions, exploring foreign environments or unmanned vehicles etc. For such system to navigate in a safe manner, high requirements of reliability and security must be fulfilled. This master's thesis explores the possibility to use the machine learning algorithm convolutional network on a robotic platform for autonomous path following. The only input to predict the steering signal is a monochromatic image taken by a camera mounted on the robotic car pointing in the steering direction. The convolutional network will learn from demonstrations in a supervised manner. In this thesis three different preprocessing options are evaluated. The evaluation is based on the quadratic error and the number of correctly predicted classes. The results show that the convolutional network has no problem of learning a correct behaviour and scores good result when evaluated on similar data that it has been trained on. The results also show that the preprocessing options are not enough to ensure that the system is environment dependent

    La necesidad de legislar la informaciĂłn a familias que esperan un hijo con sĂ­ndrome de Down

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    Desde hace ya algĂșn tiempo tanto los profesionales como las asociaciones demandan planes de actuaciĂłn que humanicen la forma en que los padres reciben la noticia pre y/o posnatal de la existencia de un niño con sĂ­ndrome de Down. Del modo de transmitir esta noticia pueden depender decisiones relevantes, como la toma de decisiĂłn sobre la continuaciĂłn o interrupciĂłn del embarazo

    La necesidad de legislar la informaciĂłn a familias que esperan un hijo con sĂ­ndrome de Down

    No full text
    Desde hace ya algĂșn tiempo tanto los profesionales como las asociaciones demandan planes de actuaciĂłn que humanicen la forma en que los padres reciben la noticia pre y/o posnatal de la existencia de un niño con sĂ­ndrome de Down. Del modo de transmitir esta noticia pueden depender decisiones relevantes, como la toma de decisiĂłn sobre la continuaciĂłn o interrupciĂłn del embarazo
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