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Applicability of certain environmental variables for modeling the potential distribution of selected centipede species
Full text linkModeliranje distribucije vrst vključuje široko paleto metodoloških pristopov in programskih orodij.
V naši raziskavi smo z različnimi modeli preverjali vplive okoljskih spremenljivk na geografsko distribucijo
strig (Chilopoda). Iz podatkovne baze CHILOBIO, ki združuje informacije o najdbah strig na območju
Slovenije, smo izbrali primerno izpolnjene zapise, ki so bili rezultat talnih vzorčenj z vzorčnimi valji. Za
kanonično korespondenčno analizo smo zbrali podatke o 18 najštevilčnejših vrstah na 29 vzorčnih lokacijah
na območju Kočevske regije. Za izvedbo dveh generaliziranih linearnih modelov in modela, ki je bil izveden
v okviru Bayesove statistike, smo uporabili podatke o prisotnostih vrste Sigibius anici na 73 vzorčnih
lokacijah na območju Slovenije. Podatki o prisotnostih vrste so bili binarnega in kvantitativnega tipa, kjer smo
z upoštevanjem števila vzorčnih enot na lokaciji dodali informacijo o vzorčnem naporu. Pred izvedbo
modelov smo nabor okoljskih spremenljivk omejili s testiranjem korelacijskih odnosov med njimi ter z
uporabo avtomatiziranih postopkov. Za kanonično korelacijsko analizo (CCA) smo izbrali
spremenljivke:nadmorsko višino, teksturo tal, vsebnostjo organske snovi v zgornjem horizontu tal ter
osončenostjo ob poletnem solsticijuza ostale modele pa le prve tri od naštetih. Na ordinacijskih diagramih
CCA so na gradientih okoljskih spremenljivk izmed preračunanih optimumov za posamezne vrste strig so
opazno izstopali le nekateri. Optimumi večine ostalih vrst so bili zbrani v izhodiščnem območju diagrama, za
kar je možnih več razlag. Rezultati ostalih treh modelov za vrsto Sigibius anici so nakazovali na slabo
ujemanje modela s podatki. Izmed uporabljenih okoljskih spremenljivk smo v generaliziranem linearnem
modelu (GLM) kot statistično pomembno določili le spremenljivko z vsebnostjo organske snovi v zgornjem
horizontu tal. Ocene napovedi modelov (AUC) so se gibale okoli vrednosti 0,5, kar pomeni, da so bile
napovedi vseh modelov blizu naključnim. Neuspešne napovedi modelov so lahko rezultat različnih virov
podatkovnega šuma. V našem primeru so potencialni viri šuma nenatančno izračunane gostote osebkov,
kršenje predpostavke o naključnosti vzorčenja in neustrezna ločljivost okoljskih spremenljivk, zaradi katere
so pogoji na lokacijah vzorčenj nenatančno izraženi.Species distribution modeling includes a variety of methodological approaches and software tools. In
our research we used various models to test the influence of some environmental variables on the
geographical distribution of centipedes (Chilopoda). We collected the centipede presence data from the
CHILOBIO database that consists of information about centipede findings in the area of Slovenia. The data
we used were gathered with a common soil sampling method with the use of sampling cylinders. We used
data of 18 most numerous centipede species from 29 sampling locations in the area of Kočevje region to
perform a canonical correspondence analysis (CCA). Furtherly we preformed two generalized linear models
(GLM) and a model preformed in the framework of Bayesian statistic. We used presence data for centipede
species Sigibius anici from 73 sampling locations throughout Slovenia. The presence data was binary and
quantitative, where we took into account the sampling effort expressed as number of sampling units on a
particular location. We tested the environmental variables for possible correlations before we used them in the
models and we made a selection of the most influential variables with an automated selection protocols. We
used variables as: terrain elevation, soil texture, content of organic matter in the topmost soil horizont and
terrain insolation in summer solstice to execute CCA and only the first three variables listed to perform the
other three models. The CCA ordination diagrams showed outlying of some species optimums for the chosen
environmental gradients. However, the optimums for the most of the species were located at the center of the
diagram, which can be due to various reasons. The results of Sigibius anici presence data modeling showed
poor model fit. Among the three of the variables used in the GLM only the variable with, content of organic
matter in the topmost soil horizont showed statistical significance. The model prediction estimates (AUC)
were around 0,5, which means that the predictions were close to random. Unsuccessful model predictions
could be due to some sources of data noise. In our case the most potential noises were: unprecisely calculated
population densities, violation of predisposition about sampling randomness and inadequate resolution of
environmental variables that failed to precisely express the conditions on the sampling locations
Electro-responsive hydrogels and their applications
No full textHidrogeli so funkcionalni materiali, primerni za uporabo na vrsto področjih zaradi svojih dobrih lastnosti in biokompatibilnosti. Zadnje čase je pozornost usmerjena tudi v raziskovanje in pripravo elektro-odzivnih hidrogelov predvsem na osnovi biopolimerov. V diplomski nalogi so predstavljeni primeri elektro-odzivnih hidrogelov in njihova potencialna uporaba. V okviru eksperimentalnega dela so bile pripravljene različne mešanice hidrogelov iz nanoceluloznih vlaken in prevodnih dodatkov na osnovi ogljika. Na podlagi električnih meritev smo hidrogelom določili specifično električno upornost in prevodnost ter ugotovili, da z dodajanjem grafenskih nanoploščic in reduciranega grafen oksida znatno povišamo električno prevodnost hidrogela. Hidrogel z dodanimi grafenskimi nanoploščicami se je izkazal za najbolj prevodnega.Hydrogels are functional materials suitable for a wide range of applications due to their good properties and biocompatibility. Recently, attention has also been focused on the research and preparation of electro-responsive hydrogels, mainly based on biopolymers. The diploma thesis presents examples of electro-responsive hydrogels and their potential applications. As part of the experimental work different mixtures of nanocellulose hydrogels and carbon-based conductive additives were prepared. Based on electrical measurements, we determined the specific electrical resistivity and conductivity of the hydrogels and acknowledged that the addition of graphene nanoplatelets and reduced graphene oxide significantly increased the electrical conductivity of the hydrogels. The hydrogel with added graphene nanoplatelets proved to be the most conductive
Characterization of microplastics using methods for determining morphology and particle size distribution
No full textMikroplastika so delci plastike manjši od 1 mm in se v okolju pojavljajo v raznoraznih barvah, oblikah in velikostih. Magistrsko delo se osredotoča predvsem na karakterizacijo različnih vzorcev mikroplastike z metodami za določevanje morfologije in porazdelitve velikosti delcev. Karakterizacija morfologije površine delcev, oblike in velikosti je še posebej pomembna pri napovedovanju vpliva mikroplastike na ekosistem. Ker je toksičnost mikroplastike v veliki meri odvisna od velikosti delcev, smo se v magistrskem delu osredotočali na opis in uporabo metod za določevanje velikosti in porazdelitve velikosti delcev. V okviru eksperimentalnega dela smo okarakterizirali različne vzorce mikroplastike z metodami za določevanje morfologije in porazdelitve velikosti delcev. Eksperimentalni del je zajemal vzorčenje vseh vzorcev mikroplastike z metodo četrtinjenja, pripravo vzorcev za analizo in primerjavo dobljenih rezultatov. Uporabili smo metode kot so vrstična elektronska mikroskopija, optična mikroskopija s pripadajočo programsko opremo in laserska difrakcija. V raziskavah so bili uporabljeni vzorci polietilena, mikroplastike iz avtomobilskih pnevmatik in biorazgradljiv P3HB. Vrstično elektronsko mikroskopijo smo uporabili za opis morfologije in oblike delcev MP. Z optično mikroskopijo in lasersko difrakcijo pa smo pridobili podatke o velikosti in porazdelitvi delcev. Na podlagi eksperimentalnega dela in rezultatov smo ugotovili, da se kot najbolj primerna metoda za določevanje velikosti delcev izkaže laserska difrakcija v mokrem, saj z njo lahko določimo velikosti delcev raznoraznim tipom vzorca in ker je hitra metoda. S primerjavo metod smo ugotovili, da dajejo zelo podobne rezultate za vzorca polietilena in avtomobilskih pnevmatik, kar kaže na zanesljivost uporabljenih metod. Še boljšo reprezentativnost in uporabnost rezultatov dobimo, če združimo ugotovitve vseh omenjenih metod ter z njihovo pomočjo pojasnimo obnašanje mikroplastike v okolju.Microplastics are plastic particles smaller than 1 mm that occur in the environment in various colours, shapes and sizes. This master thesis is primarily focused on the characterization of different microplastic samples using methods to determine particle morphology and size distribution. The characterization of the surface morphology, shape and size of the particles is particularly important for predicting the impact of microplastics on the ecosystem. Since the toxicity of microplastics is largely dependent on particle size, the focus of this work is on the description and application of methods for determining particle size and size distribution. In the experimental part, various microplastic samples were characterized using methods to determine morphology and size distribution. The experimental work included the sampling of all microplastic samples using the quartering method, sample preparation for analysis and comparison of the results obtained. Methods such as scanning electron microscopy (SEM), optical microscopy with appropriate software and laser diffraction were used. The research included samples of polyethylene, microplastics from car tires and biodegradable P3HB. Scanning electron microscopy was used to describe the morphology and shape of the microplastic particles. Data on particle size and distribution were obtained by optical microscopy and laser diffraction. Based on the experimental work and results, wet laser diffraction was found to be the most suitable method for determining particle size, as it can be used to measure particle size in different sample types and is a fast method. The comparison of the methods showed that they give very similar results for the polyethylene and car tire samples, which indicates the reliability of the methods used. Even better results are obtained when all methods can be applied to a single sample, which provides greater reliability as the methods complement each other
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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