1,820 research outputs found
The Impact of Public Funds on Private R&D Investment: New Evidence from a Firm Level Innovation Study
This paper investigates the effectiveness of a public innovation policy aimed at stimulating private R&D investment. The research will examine whether public funding increases the total spending on research or merely displaces funding from private sources. The empirical analysis is based on the Community Innovation Surveydata merged with register data. It is an evaluation of whether firms receiving public funds have on average a higher R&D intensity compared to those not receiving any such support. In order to account for possible selectivity bias, and to improve comparability of firms, two different versions of a semi-parametric matching approach are employed. The two matching estimators result in somewhat different results. The Nearest Neighbour estimator is preferred to the Kernel estimator. The results support the hypothesis suggesting that there are additive effects of public R&D financing on private research expenditures, but the only beneficiaries are small firms.Research and Development/Tech Change/Emerging Technologies,
Reward prediction error and declarative memory
Learning based on reward prediction error (RPE) was originally proposed in the context of nondeclarative memory. We postulate that RPE may support declarative memory as well. Indeed, recent years have witnessed a number of independent empirical studies reporting effects of RPE on declarative memory. We provide a brief overview of these studies, identify emerging patterns, and discuss open issues such as the role of signed versus unsigned RPEs in declarative learning
Spontaneous eyeblinks during breaking continuous flash suppression are associated with increased detection times
An eyeblink has a clear effect on low-level information processing because it temporarily occludes all visual information. Recent evidence suggests that eyeblinks can also modulate higher level processes (e.g. attentional resources), and vice versa. Despite these putative effects on different levels of information processing, eyeblinks are typically neglected in vision and in consciousness research. The main aim of this study was to investigate the timing and the effect of eyeblinks in an increasingly popular paradigm in consciousness research, namely breaking continuous flash suppression (b-CFS). Results show that participants generally refrain from blinking during a trial, that is, when they need to detect a suppressed stimulus. However, when they do blink during a trial, we observed a sharp increase in suppression time. This suggests that one needs to control for blinking when comparing detection times between conditions that could elicit phasic changes in blinking.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Investigations into the influence of the acid-base-status on the incidence of claw diseases of dairy cows
Titelblatt
Inhaltsverzeichnis
1.Einleitung
2.LiteraturĂŒbersicht
3.Material und Methoden
4.Ergebnisse
5.Diskussion
6.Schlussfolgerungen
7.Zusammenfassung
8.Summary
9.Literatuverzeichnis
Danksagung, LebenslaufIm Rahmen einer Verlaufsuntersuchung wurden ein Jahr lang acht verschiedene
Milchkuhherden beobachtet. Betreffende Betriebe wurden in jeweils ca.
vierwöchigem Abstand besucht, wobei als Probanden lahme (Grad III und höher),
trockenstehende (ab vier Wochen a.p.) sowie frischgekalbte (bis vier Wochen
p.p.) KĂŒhe ausgewĂ€hlt wurden. Von sĂ€mtlichen Probanden wurden Pansensaft-,
Harn- und Blutproben genommen sowie betreffende Milchdaten betrachtet. Die
Proben wurden auf ihren SĂ€urestatus bzw. auf damit in Verbindung stehende
Parameter untersucht, um eine akute bzw. chronisch-latente Pansenazidose als
Ursache der Klauenproblematik nachzuweisen. ZusÀtzlich wurden weitere
Stoffwechselparameter, Elektrolyte, Mineralstoffe und das Vitamin B12
berĂŒcksichtigt. Zudem wurden die RegelmĂ€Ăigkeit der Klauenpflege, die
Handhabung von Pufferzugaben zur Futterration, die Anzahl bereits geleisteter
Laktationen der einzelnen Probanden, die Tage ante bzw. post partum zum
Zeitpunkt der Probenentnahme und die Abgangsdaten der im Verlauf der zwölf
Monate lahmgehenden Tiere ĂŒber den Zeitraum der Probenentnahme hinaus
festgehalten. Die Lahmheitsinzidenz lag bei 36,5%. Die KlauensohlengeschwĂŒre
dominierten mit einem Prozentsatz von 46,9, gefolgt vom Klauenabszess (26,5%)
und der Klauenrehe (12,2%). KĂŒhe mit einmal pro Jahr gepflegten Klauen wiesen
eine nur geringfĂŒgig niedere Lahmheitsinzidenz auf als nicht routinemĂ€Ăig
klauengepflegte Tiere. In den acht untersuchten Betrieben konnte keine
Korrelation zwischen der eventuellen Einflussgrösse ïżœPufferzugabe zum Futter'
und einer im weiteren Verlauf der Laktation auftretenden Lahmheit festgestellt
werden. Die Lahmheitsinzidenz korrelierte signifikant mit steigendem Alter der
MilchkĂŒhe. Mehr als 40% der lahmen KĂŒhe verlieĂen die Herde innerhalb der
ersten zwölf Monate nach Feststellung der Lahmheit, ĂŒber 20% bereits innerhalb
der ersten sechs Monate. BezĂŒglich der Pansensaft-pH-Werte ist weder bei den
trockenstehenden noch bei den frischgekalbten und im weiteren Verlauf lahmen
KĂŒhen eine statistische AuffĂ€lligkeit zu verzeichnen gewesen. Ebenso verhielt
es sich fĂŒr die KĂŒhe, die speziell ein KlauensohlengeschwĂŒr entwickelten. Nach
Auswertung der Harnparameter der trockenstehenden KĂŒhe in Verbindung mit einer
spÀter auftretenden Lahmheit ergaben sich keine Signifikanzen. Die
Milchparameter verblieben statistisch unauffĂ€llig. BezĂŒglich der
blutchemischen Parameter fielen sowohl fĂŒr die frischgekalbten KĂŒhe, die im
weiteren Verlauf der Laktation eine Lahmheit entwickelten, als auch fĂŒr die
KĂŒhe ,die speziell ein KlauensohlengeschwĂŒr entwickelten, Signifikanzen im
Bereich der Ă-HydroxybuttersĂ€ure in Form einer Erhöhung der Werte auf (p=0,007
bzw. p=0,000). Die Faktoren, die fĂŒr die untersuchten Betriebe offensichtlich
eine wichtige Rolle spielen und zu optimieren sind, sind eine routinemĂ€Ăig
professionelle Klauenpflege und eine verbesserte Anpassung des
Energiehaushaltes der einzelnen MilchkĂŒhe an die peripartale Phase. AuĂerdem
sind die Haltungsbedingungen bezĂŒglich des Kuhkomforts zu ĂŒberdenken. Dies
gilt auch im besonderen MaĂe fĂŒr die Nachzucht der Herde.Within the scope of a longitudinal study, eight different dairy cow herds were
observed over the course of twelve months. The relevant dairy farms were
visited every four weeks. Selected test specimens were lame cows (3rd degree
and above), non-lactating (dry) cows (up to four weeks a.p.) and recently
calved cows (up to four weeks p.p.). Ruminal fluid, urine, and blood samples
were taken from all test specimens and milk data from the most recent milk
control examination was collected. The samples were predominantly examined for
acidity status and the related parameters in order to establish an acute or
chronic latent ruminal acidosis as the cause for the claw problems. In
addition, further metabolic parameters, electrolytes, minerals and vitamin B12
were taken into account. Furthermore, claw trimming and the use of buffer
additions to the feed, the number of past lactation periods of each test
specimen ,the number of days ante or post partum at the time of sampling and
the loss data of lame animals during the course of the twelve month-long study
were recorded for each herd. The lameness incidence was 36.5 %. In terms of
ascertained diagnoses, the sole ulcer dominated with 46.9%, followed by the
foot abscess (26.5%) and laminitis (12.2%). The influencing variable "claw
trimming" was notable because cows which received treatment once annually had
an only somewhat lower incidence than those which did not receive regular claw
trimming. No correlation could be made in the eight examined dairy farms
between the potential influencing variable "buffer additions" and lameness
occurring later during lactation. The lameness incidence correlated
significantly with increased age of the dairy cows. More than 40% of the lame
cows left the herd within the first twelve months following the determined
lameness; more than 20% left within the first six months. With regard to the
ruminal fluid pH level, no further statistical distinction was made in the dry
cows or in the recently calved cows or in the cows which became lame later.
Nor could such a statistical distinction be made with regard to cows which
developed a sole ulcer. Upon analysis of the urine parameter of the dry cows
in connection with a later occurring lameness, no significances resulted. The
milk parameters remained statistically insignificant. With regard to the
chemical parameters of the blood, significant increases appeared in the
Ă-hydroxybutyric acid values for the recently calved cows that developed a
lameness later during lactation, as well as for cows that specifically
developed a sole ulcer (p=0.007 p=0.000). The factors which obviously play an
important roll for the farms examined and could possibly be optimized are
routine professional claw trimming and an improved adaptation of the energy
needs of each dairy cow to the peripartal phase. In addition, the housing
conditions with regard to cow comfort should be reconsidered, in particular
for the offspring of the herd
Efficient computation of rank probabilities in posets
As the title of this work indicates, the central theme in this work is the computation of rank probabilities of posets. Since the probability space consists of the set of all linear extensions of a given poset equipped with the uniform probability measure, in first instance we develop algorithms to explore this probability space efficiently. We consider in particular the problem of counting the number of linear extensions and the ability to generate extensions uniformly at random. Algorithms based on the lattice of ideals representation of a poset are developed.
Since a weak order extension of a poset can be regarded as an order on the equivalence classes of a partition of the given poset not contradicting the underlying order, and thus as a generalization of the concept of a linear extension, algorithms are developed to count and generate weak order extensions uniformly at random as well. However, in order to reduce the inherent complexity of the problem, the cardinalities of the equivalence classes is fixed a priori. Due to the exponential nature of these algorithms this approach is still not always feasible, forcing one to resort to approximative algorithms if this is the case. It is well known that Markov chain Monte Carlo methods can be used to generate linear extensions uniformly at random, but no such approaches have been used to generate weak order extensions. Therefore, an algorithm that can be used to sample weak order extensions uniformly at random is introduced.
A monotone assignment of labels to objects from a poset corresponds to the choice of a weak order extension of the poset. Since the random monotone assignment of such labels is a step in the generation process of random monotone data sets, the ability to generate random weak order extensions clearly is of great importance. The contributions from this part therefore prove useful in e.g. the field of supervised classification, where a need for synthetic random monotone data sets is present.
The second part focuses on the ranking of the elements of a partially ordered set. Algorithms for the computation of the (mutual) rank probabilities that avoid having to enumerate all linear extensions are suggested and applied to a real-world data set containing pollution data of several regions in Baden-WĂŒrttemberg (Germany). With the emergence of several initiatives aimed at protecting the environment like the REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) project of the European Union, the need for objective methods to rank chemicals, regions, etc. on the basis of several criteria still increases. Additionally, an interesting relation between the mutual rank probabilities and the average rank probabilities is proven.
The third and last part studies the transitivity properties of the mutual rank probabilities and the closely related linear extension majority cycles or LEM cycles for short. The type of transitivity is translated into the cycle-transitivity framework, which has been tailor-made for characterizing transitivity of reciprocal relations, and is proven to be situated between strong stochastic transitivity and a new type of transitivity called delta*-transitivity. It is shown that the latter type is situated between strong stochastic transitivity and a kind of product transitivity. Furthermore, theoretical upper bounds for the minimum cutting level to avoid LEM cycles are found. Cutting levels for posets on up to 13 elements are obtained experimentally and a theoretic lower bound for the cutting level to avoid LEM cycles of length 4 is computed.
The research presented in this work has been published in international peer-reviewed journals and has been presented on international conferences. A Java implementation of several of the algorithms presented in this work, as well as binary files containing all posets on up to 13 elements with LEM cycles, can be downloaded from the website http://www.kermit.ugent.be
A revised polytomous key for the identification of species of the genus Xiphinema Cobb, 1913 (Nematoda : Longidoridae) with exclusion of the X. americanum-group : supplement 1
Description of Xiphinema thorneanum n. sp. and observations on some species of the genus (Nemata : Longidoridae)
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