64 research outputs found
Sex differences in feeding visit rates in Northern Wheatears Oenanthe oenanthe
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 parentsâ 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 sexesâ 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
StenskvÀttan (Oenanthe oenanthe) Àr en liten insektsÀtande tÀtting som lever i öppna landskap. BÄda förÀldrar matar kullen pÄ ca fem ungar, men kunskapen om hur könen fördelar sina anstrÀngningar Àr liten.
I den hÀr studien undersöker jag skillnader i matningsfrekvens mellan hane och hona av stenskvÀtta i förhÄllande till ungarnas Älder, deras antal och kvaliteten pÄ 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 förÀlderns kön bestÀmdes frÄn filmer av boet. Jag undersökte ocksÄ om förÀldrarnas matningsfrekvens Àndras under tiden ungarna Àr i boet.
Jag antog att: (1) hanen skulle mata oftare relativt honan nÀr ungarna Àr smÄ, och att rollerna skulle bli ombytta (d.v.s. honan skulle bli förÀldern med högst matningsfrekvens) nÀr ungarna blivit Àldre; (2) skillnader i matningsfrekvens mellan förÀldrarna skulle vara mindre ju fler ungar det Àr i boet; (3) skillnader i matningsfrekvens mellan förÀldrarna skulle vara relativt liten nÀr kvaliteten pÄ reviret var lÄg; och (4) förÀldrarna skulle öka matningsfrekvensen allteftersom ungarna vÀxte. Antagandena Àr baserade pÄ teorin om begrÀnsade resurser.
Jag fann visst stöd för skillnader i matningsfrekvens mellan könen. Hanen hade en större del av matningen nÀr ungarna var smÄ men det var ingen skillnad nÀr ungarna var större. Det var ingen skillnad mellan hane och hona med varierande antal ungar. Kvaliteten pÄ reviret hade en liten effekt pÄ könens matningsfrekvens, men bara nÀr ungarnas Älder togs med i analysen. Matningsfrekvensen var högre för Àldre ungar Àn för yngre.
Den hÀr studien Àr den första att förse information om hur stenskvÀttor beter sig i boet i förhÄllande till dess kön och bör utgöra grunden för framtida forskning pÄ könsskillnader hos stenskvÀtta
SmÄskalig utsÀdesproduktion
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 förbÀttra det ekonomiska resultatet.
Denna studie avser att studera de ekonomiska fördelar och problem som en grupp
lantbrukare möter dÄ de via en gemensam investering i smÄskalig utsÀdesproduktion
strÀvar efter att öka graden av en vertikal integration i sina lantbruksföretag. I
dagslÀget Àr de spannmÄlsodlare med betydande arealer som upplever att
insatsvarorna blir en allt större kostnadspost. VidareförÀdlingen i deras fall innebÀr
att lantbrukarna producerar certifierat utsÀde i en gemensam anlÀggning för eget
bruk och för försÀljning.
Studien grundar pÄ intervjuer med sex lantbrukare. Tre stycken av dem tillhör den
grupp som i studien benĂ€mns âförĂ€dlareâ och de tre övriga benĂ€mns âköpareâ.
Gemensamt för samtliga Àr att de har stor kunskap om spannmÄlsbranschen och
goda insikter i problematiken kring produktionen av utsÀde.
Studien har för avsikt att dels visa vilka ekonomiska incitament som uppstÄr dÄ
lantbrukare samverkar via en investering i en vertikalt integreration, dels att
analysera de olika problem som uppstÄr. Arbetets teoretiska referensram grundas pÄ
agentteorin. Teorin beskriver de olika agentproblem som kan uppstÄ i en gemensam
organisatorisk struktur. De problem som beaktas Àr beslutsfattarproblemet,
portföljproblemet, horisontproblemet samt kontrollproblemet.
Studien visar att det krÀvs stora volymer för att nÄ god lönsamhet vid produktionen
av certifierat utsÀde. Dessutom Àr en god relation till kunderna vÀsentlig för att fÄ en
lÄngsiktig lönsamhet. Priset pÄ utsÀde och spannmÄl i handeln har stor betydelse för
det ekonomiska resultatet. Det Àr Àven vÀsentligt att lantbrukarna har en god
uppfattning om vilka sorter förÀdlingsindustrin efterfrÄgar
StyrelsesammansÀttning - och dess inverkan pÄ företagets prestation
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
ELECTROENCEPHALOGRAPHIC AND BEHAVIORAL AROUSAL EFFECTS OF SMALL DOSES OF NICOTINE: A NEUROPSYCHOPHARMACOLOGICAL STUDY *
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75488/1/j.1749-6632.1967.tb13726.x.pd
Differential actions of m and n cholinergic agonists on the brainstem activating system
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
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
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
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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