50 research outputs found
Målinger i troposfæren med ALOMAR RMR lidar: Temperaturmålinger med bruk av rotasjons Raman spektrum og bestemmelse av dens optiske overlap.
No full textAlomar troposfæriske lidar var ikke operativ grunnet en feil med laseren og trengte en erstatter. Den fikk en ny laser under skrivingen av denne oppgaven.
I denne oppgaven ble det prøvd en midlertidig løsning hvor RMR-lidaren på ALOMAR ble brukt for troposfæremålinger. RMR-lidaren er ustyrt med rotasjons-Raman kanaler som er brukt til å måle temperaturer i troposfæren. RMR-lidaren er konstruert for målinger i den øvre atmosfære og har derfor en ukomplett optisk overlap i tropsfæren. Den optiske overlapsfunksjonen for RMR teleskopene vil bli funnet på forskjellige metoder slik at RMR-lidaren kan bli brukt for andre målinger i troposfæringen. Overlapsfunksjonen er og blitt brukt til å sammenligne data fra RMR og den troposfæriske lidaren.The ALOMAR tropospheric lidar was not operative as the laser was damaged and needed a replacement. It got the new laser during the writing of this thesis.
In this thesis I will try to give a backup solution using the RMR-lidar for tropospheric measurements, which is also located at ALOMAR. The RMR-lidar is equipped with rotational Raman channels which will be used to calculate temperature in the troposphere.
As the RMR-lidar is built for upper atmospheric measurements the telescopes have an incomplete optical overlap in the troposphere. The optical overlap function for the RMR telescopes will be determined using different methods, such that the RMR-lidar can be used for other measurements in the troposphere. The overlap function will then briefly be used to compare data from tropospheric lidar
Målinger i troposfæren med ALOMAR RMR lidar: Temperaturmålinger med bruk av rotasjons Raman spektrum og bestemmelse av dens optiske overlap.
No full textAlomar troposfæriske lidar var ikke operativ grunnet en feil med laseren og trengte en erstatter. Den fikk en ny laser under skrivingen av denne oppgaven.
I denne oppgaven ble det prøvd en midlertidig løsning hvor RMR-lidaren på ALOMAR ble brukt for troposfæremålinger. RMR-lidaren er ustyrt med rotasjons-Raman kanaler som er brukt til å måle temperaturer i troposfæren. RMR-lidaren er konstruert for målinger i den øvre atmosfære og har derfor en ukomplett optisk overlap i tropsfæren. Den optiske overlapsfunksjonen for RMR teleskopene vil bli funnet på forskjellige metoder slik at RMR-lidaren kan bli brukt for andre målinger i troposfæringen. Overlapsfunksjonen er og blitt brukt til å sammenligne data fra RMR og den troposfæriske lidaren
Replication Data for: Hunting method affects cortisol levels in harvested mountain hares (Lepus timidus)
No full textThis dataset contains information on cortisol levels in Norwegian mountain hares (Lepus timidus) after hunting. The dataset includes cortisol level measurements from 20 hares that were hunted using dogs and 32 hares that were hunted without the use of dogs. For addittional information on georeferencing, age, concentration of other blood hormones etc contact senior author. Abstract (of article):
Direct effect of hunting on hunted individuals and populations have been well-known for a long time. However, there has recently been an increased focus also on the indirect, non-lethal effects of hunting. When approached by a possible threat such as a predator, prey releases various stress hormones into the bloodstream. Cortisol is one of these hormones and the blood concentration is an indicator of stress levels in mammals. Here we report on a study on effects of using hunting dogs versus walk-up shooting on mountain hare blood cortisol levels. We sampled 20 hares hunted using dogs and 32 control hares hunted without using dogs. On average cortisol levels in hares hunted using dogs was 44.6 ng/ml, while hares harvested without being chased by dogs was 6.8 ng/ml. Based on the blood hormone levels of this study we cannot conclude if the elevated cortisol levels we see in the hares hunted using dogs was harmful to the hares had they not been shot. However, given what is known about effects of chronic stress, we would caution against repeated chases of individual hares. The cumulative effect of stressors including hunting is likely crucial for any effects on reproduction and survival. Thus, there is a need to evaluate the long-term effects of hunting chases and other human activities on mountain hare stress hormone levels, and to investigate the long-term effect on hare behavior, space use, survival, reproduction and recruitment
Author's personal copy Decision processes in temporal discrimination
No full textThis article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. The processing dynamics underlying temporal decisions and the response times they generate have received little attention in the study of interval timing. In contrast, models of other simple forms of decision making have been extensively investigated using response times, leading to a substantial disconnect between temporal and non-temporal decision theories. An overarching decision-theoretic framework that encompasses existing, non-temporal decision models may, however, account both for interval timing itself and for time-based decision-making. We sought evidence for this framework in the temporal discrimination performance of humans tested on the temporal bisection task. In this task, participants retrospectively categorized experienced stimulus durations as short or long based on their perceived similarity to two, remembered reference durations and were rewarded only for correct categorization of these references. Our analysis of choice proportions and response times suggests that a two-stage, sequential diffusion process, parameterized to maximize earned rewards, can account for salient patterns of bisection performance. The first diffusion stage times intervals by accumulating an endogenously noisy clock signal; the second stage makes decisions about the first-stage temporal representation by accumulating first-stage evidence corrupted by endogenous noise. Reward-maximization requires that the second-stage accumulation rate and starting point be based on the state of the first-stage timer at the end of the stimulus duration, and that estimates of non-decision-related delays should decrease as a function of stimulus duration. Results are in accord with these predictions and thus support an extension of the drift-diffusion model of static decision making to the domain of interval timing and temporal decisions
Eduard Zander Abenteurer, Naturforscher, Maler, Architekt und Handwerker in Äthiopien – Eine Biographie
No full textThough Eduard Zander’s original sketchbook with drawings in pen and ink – showing the remote Simen Mountain area – is still preserved in London, his adventuresome life and his scientific and artistic work as a biologist, architect or artisan is scarcely known in 19th century Ethiopian history. In the present article the author makes an attempt at Zander’s biography, adding the missing links and correcting the errors of his few predecessors; furthermore, he tries to produce recently dicovered source-material in an updated form
Effects of Temperature and pH on Recombinant Thaumatin II Production by Pichia pastoris
No full textThe sweet protein thaumatin is emerging as a promising sugar replacer in the market today, especially in the food and beverage sector. Rising demand for its production necessitates the large-scale extraction of this protein from its natural plant source, which can be limited in terms of raw material availability and production costs. Using a recombinant production technique via a yeast platform, specifically, Pichia pastoris, is more promising to achieve the product economically while maintaining batch-to-batch consistency. However, the bioproduction of recombinant proteins requires the identification of optimal process variables, constituting the maximal yield of the product of interest. These variables have a direct effect on the growth of the host organism and the secretion levels of the recombinant protein. In this study, two important environmental factors, pH, and temperature were assessed by cultivating P. pastoris in shake flasks to understand their influence on growth and the production levels of thaumatin II protein. The results from the pH study indicate that P. pastoris attained a higher viable cell density and secretion of protein at pH 6.0 compared to 5.0 when grown at 30 °C. Furthermore, within the three levels of temperatures investigated when grown at pH 6.0, the protein levels were the highest at 30 °C compared to 20 and 25 °C, whereas 25 °C exhibited the highest viable cell density. Interestingly, the trend observed from the qualitative effects of temperature and pH occurred in all the media that was investigated. These results broaden our understanding of how pH and temperature adjustment during P. pastoris cultivation aid in enhancing the production yields of thaumatin II prior to optimising the fed batch bioreactor operation.sponsorship: This research was funded by the KU Leuven Research Fund through project C24/18/046 and by the Research Foundation Flanders (FWO) through project G0B4121N. Author Simen Akkermans was funded by the Research Foundation Flanders (FWO), grant number 1224620N. (KU Leuven Research Fund|C24/18/046, Research Foundation Flanders (FWO)|1224620N, Research Foundation Flanders (FWO)|G0B4121N)status: Publishe
Lithic technological responses to Late Pleistocene glacial cycling at Pinnacle Point Site 5-6, South Africa
No full textabstract: There are multiple hypotheses for human responses to glacial cycling in the Late Pleistocene, including changes in population size, interconnectedness, and mobility. Lithic technological analysis informs us of human responses to environmental change because lithic assemblage characteristics are a reflection of raw material transport, reduction, and discard behaviors that depend on hunter-gatherer social and economic decisions. Pinnacle Point Site 5–6 (PP5-6), Western Cape, South Africa is an ideal locality for examining the influence of glacial cycling on early modern human behaviors because it preserves a long sequence spanning marine isotope stages (MIS) 5, 4, and 3 and is associated with robust records of paleoenvironmental change. The analysis presented here addresses the question, what, if any, lithic assemblage traits at PP5-6 represent changing behavioral responses to the MIS 5-4-3 interglacial-glacial cycle? It statistically evaluates changes in 93 traits with no a priori assumptions about which traits may significantly associate with MIS. In contrast to other studies that claim that there is little relationship between broad-scale patterns of climate change and lithic technology, we identified the following characteristics that are associated with MIS 4: increased use of quartz, increased evidence for outcrop sources of quartzite and silcrete, increased evidence for earlier stages of reduction in silcrete, evidence for increased flaking efficiency in all raw material types, and changes in tool types and function for silcrete. Based on these results, we suggest that foragers responded to MIS 4 glacial environmental conditions at PP5-6 with increased population or group sizes, ‘place provisioning’, longer and/or more intense site occupations, and decreased residential mobility. Several other traits, including silcrete frequency, do not exhibit an association with MIS. Backed pieces, once they appear in the PP5-6 record during MIS 4, persist through MIS 3. Changing paleoenvironments explain some, but not all temporal technological variability at PP5-6.The article is published at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.017405
Multiple resonances of a moving oscillating surface disturbance on a shear current
No full textauthor post print, available June 201
Authorship Identification of Research Papers
No full textAuthorship identification is a technique used to identify anonymous documents by identifying and extracting an authors stylometric features. The focus of this thesis is to apply an authorship identification technique, classification, to a set of research papers to determine the authorship. We go through theory and previous work of authorship identification before we present the implemented system. In the end, we perform two separate experiments and discuss their results.
The experiments show good results in specific cases, and we achieve an accuracy of 100% in the best case. The algorithms used are support vector machines, artificial neural networks, decision trees, random forests and the k-nearest neighbor. In our experiments support vector machines and artificial neural network had the best performance while decision trees performed worst.
Based on our results we propose caution when applying authorship identification before or after having performed a double-blind review, or for an author to use authorship identification to acquire an unbiased review of a research paper. Even though we state that authorship identification should be used with caution, it is still a great tool and gives a general idea of finding the authorship of an anonymous document
Authorship Identification of Research Papers
No full textAuthorship identification is a technique used to identify anonymous documents by identifying and extracting an authors stylometric features. The focus of this thesis is to apply an authorship identification technique, classification, to a set of research papers to determine the authorship. We go through theory and previous work of authorship identification before we present the implemented system. In the end, we perform two separate experiments and discuss their results.
The experiments show good results in specific cases, and we achieve an accuracy of 100% in the best case. The algorithms used are support vector machines, artificial neural networks, decision trees, random forests and the k-nearest neighbor. In our experiments support vector machines and artificial neural network had the best performance while decision trees performed worst.
Based on our results we propose caution when applying authorship identification before or after having performed a double-blind review, or for an author to use authorship identification to acquire an unbiased review of a research paper. Even though we state that authorship identification should be used with caution, it is still a great tool and gives a general idea of finding the authorship of an anonymous document
