1,720,986 research outputs found
A Visual Guide to General Chemistry Topics
Get PDFUsing some of the most frequently asked questions during General and Essentials of Chemistry tutoring sessions, this compilation of illustrated worksheets and concept maps was assembled. Left black and white, the pages of this booklet are meant to help facilitate student interaction with their own notes, allowing them to color code, fill in, and annotate whatever they see fit. In bringing material that is typically presented to students via textbook or plain text in a way that is illustrated and creative, it helps to reach the visual side of students’ brains and allow them to see connections that they might otherwise not. The pages in this booklet are meant to be used both as standalone pages, and as a compiled book. Suggested use of the pages include “whiting out” portions of pages, allowing students to fill them in themselves, or giving the pages to students after lecture has occurred, allowing the pages to act as a visual review of important concepts. Additionally, students should be encouraged to make their own “visual notes”
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
The Effects of Hydroperiod on the Head Morphology of Long-Toed Salamanders (Ambystoma macrodactylum)
Get PDFPhenotypic plasticity has been observed in many organisms from mammals to plants. In particular amphibians are susceptible to plasticity before metamorphosis. Hydroperiod (the amount oftime water is present in a pond) is a significant factor in amphibian development. It has been indicated to cause phenotypic plasticity in the head morphology of salamanders. Cannibalistic and typical head morphologies have been recorded in the long-toed salamander Ambystoma macrodactylum. Larval salamanders in both short and long hydroperiod ponds were observed using macro-photography. Geometric morphometries was then used to analyze head shapes. The two sites were sampled throughout the summer of 2003 to view if there was a morphological difference between larval salamanders in long and short hydroperiod ponds. The larval salamanders exhibited typical and non-typical morphologies depending on hydroperiod
Analysis of Antimicrobial Peptide Efficacy Against Chytridiomycosis from Skin Secretions of Columbia Spotted Frogs (Lithobates luteiventris)
Get PDFAmphibian populations have been declining in size in recent years. A major contributing factor to this decline is the fungal disease chytridiomycosis. Chytridiomycosis occurs when the zoospores of the fungus Batrachochytrium dendrobatidis (Bd) imbed into amphibian skin and disrupt the homeostatic functions the skin provides, leading to death in most amphibians. Amphibian skin can produce antimicrobial peptides (AMPs) that inhibit Bd infection. The goal of this experiment was to determine whether or not the amount and type of AMPs a frog produces affect its ability to defend against chytridiomycosis. Columbia spotted frogs were chosen as a model organism because they vary in susceptibility to the disease, yet their populations have not been drastically affected by the fungus. Skin secretion samples were collected from ten Columbia spotted frogs at four different locations in western Montana (40 samples total). The protein concentration for each sample was determined using a micro BCS assay. The minimal inhibitory concentrations (MICs) were determined using 96 well plate growth inhibition assays. In the assay, a set of ten protein dilutions from each frog (ranging from 100-1000 ?g/mL) were used. The Bd was grown in each dilution and growth was measured after four days as the change in absorbance measured at 492 nm. Infection load of frogs was determined using Quantitative PCR analysis. From the data collected, there was no statistically significant correlation between the MIC and infection load
Biochemical Analysis of Insect Camouflage in Manduca sexta, the Tobacco Hornworm
Get PDFManduca sexta (Tobacco Hornworm) larvae exhibit diet-induced adaptation, demonstrating green coloration in their natural environment but becoming a pale blue when placed on a lab diet lacking plant material. I hypothesized that the color change observed in the Tobacco Hornworm was induced by the dietary intake of a plant pigment of orange or yellow color (specifically ?-carotene). The pigment ?-carotene is highly hydrophobic, so I hypothesized that it was traveling to the skin via a lipoprotein transport pathway. Hornworms were reared and then bled to extract hemolymph. Ultracentrifugation was used to float out the lipoproteins from the hemolymph. Lipoprotein isolation was confirmed by gel electrophoresis. The lipoproteins isolated from plant-fed insects did indeed contain a bright yellow pigment. UV-visible spectroscopy supported ?-carotene as the pigment being carried by the lipoproteins and responsible for inducing the insect’s color change
The Effects of Hydroperiod on the Morphology of the Long-Toed Salamander Ambystoma macrodactylum
Get PDFThis study was conducted to determine whether salamander larvae of Ambystoma macrodactylum growing in short hydroperiod ponds develop a cannibalistic morphology while those growing in a long hydroperiod pond develop a typical morphology. Hand and dip net capturing techniques were used to collect the larvae. They were then preserved in formalin and stored in 95% ethanol solution. Six measurements were then taken: snout-vent length, head width at gills, head width at eyes, head width at jaws, head length, and interocular width. Snout-vent-length was then scaled to the other measurements to determine differences in body shape. Using an ANOVA statistical test, these shape measurements were compared to determine if morphology of salamander larvae differ between the two sites. Results showed that there was a significant difference in morphology for all measurements except snout-vent length to interocular width. While the body morphologies from the two sites were different, the morphology from the short hydroperiod pond was not cannibalistic. Possible explanations for this include genetics, density, and diet
Biogeographic origin of the Hawaiian pteridophyte, Diplopterygiutn pinnatum, (Gleicheniaceae) as assessed by phylogenetic analysis of atpfi and trnG-R chloroplast DNA regions
Get PDFDespite the fact that pteridophytes, commonly known as ferns, account for a large percentage of Hawaii’s vascular plants, few studies have been conducted to determine their biogeographical origins. This study aimed to determine an origin and a pathway of dispersal for the endemic Hawaiian fern, Diplopterygium pinnatum (Gleicheniaceae). Molecular and evolutionary phylogenetic analysis was employed using obtained chloroplast DNA sequences from the gene atpfi and the genes and noncoding spacer region trnG-R. Combined analysis with trnL-F and rbcL sequences from another study was also performed. Taking into account conclusions from a previous study, two possible origins and dispersal mechanisms were considered. The first hypothesis was that D. pinnatum originated in the Indo-Pacific region and was dispersed through spores in the Pacific jetstream. The second hypothesis was that D. pinnatum was dispersed to Hawaii via ITCZ/Hadley Cell Shift from an origin somewhere in the Austral region of the Pacific Ocean. Maximum likelihood and maximum parsimony trees produced similar relationships with similar bootstrap support. However, this study failed to differentiate between the two hypotheses and therefore the most likely origin and dispersal mechanism could not be determined
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