111,992 research outputs found
The role of niche breadth, resource availability and range position on the life history of butterflies
No full textWe analysed the relationship between three life history characteristics
(mobility, length of flight period and body size) and niche breadth
(larval host plant specificity and adult habitat breadth), resource
availability (distribution and abundance of host plants) and range
position (distance between the northernmost distribution record and
southernmost point of Finland) of the butterfly fauna of Finland. The
data is based on literature and questionnaires. Often in across species
studies phylogeny may create spurious relationships between life-history
and ecological variables. We took the phylogenetic relatedness of
butterfly species into account by analysing the data with
phylogenetically independent contrasts (CAIC method). Butterfly mobility
was positively related to the niche breadth, resource availability and
range position. The length of the flight period was negatively related
to the range position, indicating that the species at the northern edge
of their distribution range have shorter flight period than species
which are further way from the range edge. After controlling for the
phylogenetic relatedness we found no significant correlations between
body size and niche breadth, resource availability or range position. We
suggest that the relationship between the length of the flight period
and range position may arise as a consequence of lower hatching
asynchrony in edge species as a result of lower environmental variance
in larval growth conditions. Our results on the mobility suggest that
there is selection pressure towards lower migration rate in species that
have restricted niche breadth, low resource availability and in species
that are on the northern edge of their geographical distribution range.
In such species, selection against mobile individuals is likely to
result from the decreased probability of finding another habitat patch
suitable for egg laying
author-bios-SRD-19-0063.R1 – Supplemental material for The Network Structure of Police Misconduct
No full textSupplemental material, author-bios-SRD-19-0063.R1 for The Network Structure of Police Misconduct by George Wood, Daria Roithmayr and Andrew V. Papachristos in Socius</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
Negative density-distribution relationship in butterflies
No full textBackground.
Because "laws of nature" do not exist in ecology, much of the foundations of community ecology rely on broad statistical generalisations. One of the strongest generalisations is the positive relationship between density and distribution within a given taxonomic assemblage; that is, locally abundant species are more widespread than locally sparse species. Several mechanisms have been proposed to create this positive relationship, and the testing of these mechanisms is attracting increasing attention.
Results.
We report a strong, but counterintuitive, negative relationship between density and distribution in the butterfly fauna of Finland. With an exceptionally comprehensive data set (data includes all 95 resident species in Finland and over 1.5 million individuals), we have been able to submit several of the mechanisms to powerful direct empirical testing. Without exception, we failed to find evidence for the proposed mechanisms creating a positive density-distribution relationship. On the contrary, we found that many of the mechanisms are equally able to generate a negative relationship.
Conclusion.
We suggest that one important determinant of density-distribution relationships is the geographical location of the study: on the edge of a distribution range, suitable habitat patches are likely to be more isolated than in the core of the range. In such a situation, only the largest and best quality patches are likely to be occupied, and these by definition can support a relatively dense population leading to a negative density-distribution relationship. Finally, we conclude that generalizations about the positive density-distribution relationship should be made more cautiously.peerReviewe
HARVESTING STRATEGIES IN A FISH STOCK DOMINATED BY LOW-FREQUENCY VARIABILITY: THE NORWEGIAN SPRING-SPAWNING HERRING (CLUPEA HARENGUS)
No full textHeavy positively autocorrelated natural fluctuations in a fisheries stock level are problematic for fisheries management, and collapses in the stock dynamics are difficult to avoid. In this paper, we compare three different harvesting strategies (proportional harvesting, threshold harvesting, and proportional threshold harvesting) in an autocorrelated and heavily fluctuating fishery — the Norwegian spring-spawning herring (Clupea harengus) — in terms of risk of quasi-extinction, average annual yield, and coefficient of variation of the yield. Contrary to general expectations, we found that the three strategies produce comparable yields and risks of quasi-extinction. The only observable difference was slightly higher yield and variation in the proportional threshold strategy when the yield is optimized. Thus, it remains an open question as how to characterize the circumstances when it is particularly needful to apply threshold levels in harvest policies.Resource /Energy Economics and Policy,
Infective prey leads to a partial role reversal in a predator-prey interaction
No full textAn infective prey has the potential to infect, kill and consume its predator. Such a prey-predator relationship fundamentally differs from the predator-prey interaction because the prey can directly profit from the predator as a growth resource. Here we present a population dynamics model of partial role reversal in the predator-prey interaction of two species, the bottom dwelling marine deposit feeder sea cucumber Apostichopus japonicus and an important food source for the sea cucumber but potentially infective bacterium Vibrio splendidus. We analyse the effects of different parameters, e.g. infectivity and grazing rate, on the population sizes. We show that relative population sizes of the sea cucumber and V. Splendidus may switch with increasing infectivity. We also show that in the partial role reversal interaction the infective prey may benefit from the presence of the predator such that the population size may exceed the value of the carrying capacity of the prey in the absence of the predator. We also analysed the conditions for species extinction. The extinction of the prey, V. splendidus, may occur when its growth rate is low, or in the absence of infectivity. The extinction of the predator, A. japonicus, may follow if either the infectivity of the prey is high or a moderately infective prey is abundant. We conclude that partial role reversal is an undervalued subject in predator-prey studies.Peer reviewe
The Management of High Seas Fisheries
No full textA new and acute management problem, now the focus of a major U.N. conference, has arisen in recent years in international fisheries. The problem concerns the management of transboundary fishery resources, in the form of resources to be found in both the coastal state EEZ and the adjacent high seas. The resources are commonly referred to as "straddling" stocks. This article provides a preliminary exploration of the management issue. It reviews the historical and legal background and asks how far the now well developed economic analysis of the management of transboundary fishery resources in the form of resources "shared" by two or more coastal states will take us in examining this second and more recent transboundary fishery management problem. The answer is a very limited distance only. The article concludes by pointing to questions arising from this resource management issue demanding further research.Transboundary fishery resources, straddling stocks, theory of dynamic games, Environmental Economics and Policy, Public Economics,
Využití sociálních médií v B2B prodeji
No full textTato diplomová práce se zabývá tím, jak mohou B2B obchodníci využívat sociální média v prodeji. Na základě systematické rešerše literatury, autor zjistil, že akademici, zkoumající danou problematiku, navrhují další výzkum, a to: v kterých konkrétních krocích se dají využít sociální média v prodeji (Salo, 2017). Autor se na základě toho rozhodl zjistit, jaké sociální sítě, různé technologie a pluginy se dají využít v B2B prodeji - tzv. social sellingu. Social selling se v této práci týká primárně procesu akvizice a okrajově péčí o stávající zákazníky. Autor si vybral kvalitativní průzkum pomocí 10 hloubkových polo-strukturovaných rozhovorů, aby odhalil jak, která sociální média to jsou, tak i motivaci prodejců, proč tato média používat/nepoužívat. Aby autor dodržel správnost vyhodnocení výsledků, data byla analyzována pomocí Tématické analýzy, která v této studii vykrystalizovala 2 hlavní strategické přístupy v social sellingu. Tyto přístupy (tzv. Push a Pull strategie) obsahují praktické příklady a konkrétní aktivity, které mohou prodejci využívat v každodenní praxi. Tyto výsledky jsou prezentovány s důrazem na praktičnost a jednoduchost implementace. Tvoří proto hlavní přínos autorovo výzkumu. V poslední části autor zmiňuje výzvy a manažerská doporučení, které mohou obchodníci využít v každodenním pracovním životě.This diploma thesis focuses on social media usage in B2B sales. Based on the systematic literature review conducted by the author, he has found out that recent researchers (Salo, 2017) suggest further research in the area of how and in which sales phase should various social networking sites, technologies and plugins used. To further fill this research gap, author decided to identify these social media and their usage among B2B salespeople in the so-called social selling process. The social selling process in this thesis applies mainly to acquiring new prospects and tangentially to taking care of existing clients (follow-up step). Author has chosen a qualitative research method via conducting 10 in-depth semi-structured interviews to reveal these instruments as well as motivation of a sales person on why to use social media in the selling process. The collected data was analyzed using Thematic analysis to ensure the right procedure and to identify main themes which crystalized into 2 main strategic approaches in social selling. These approaches (Push and Pull) include practical examples of concrete activities which sales people can use in their daily jobs and are presented with focus on practicality and ease of implementation. These also form the main contribution of author`s research. In the last part, author mentions challenges in social selling and recommended managerial implications for salesforce
TeX v jednoduchém unixovém prostředí
No full textsummary:Při ladění TeXového dokumentu potřebujeme mnohokrát opakovaně pouštět TeX, podívat se, jak dopadl výsledek v prohlížeči DVI nebo PDF souboru, mrknout na výpis TeXu na terminálu, podívat se případně do logu a celou činnost opakovat. V tomto článku je ukázáno, jak tuto práci dělá autor článku. Proces "editor-TeX-kuk" je zde podporován jednoduchými unixovými nástroji: bashovým skriptem texloop, který si autor pro tyto účely vytvořil, dále terminálem Xterm a jednoduchým editorem, který umí navázat na klávesovou zkratku spuštění příkazu v systému. Čtenář se zde může inspirovat a přizpůsobit tyto nástroje svým vlastním potřebám. V článku je popsána funkce skriptu texloop, dále je neformálně rozveden dlouholetý vývoj autorova vztahu k textovým editorům a konečně je zde uvedena konfigurace terminálu Xterm, aby vyhovoval českému prostředí jak v kódování ISO-8859-2, tak v kódování UTF-8. Pro kódování UTF-8 si v závěru článku vygenerujeme TeXový formát csplain.summary:By debugging a TeX document it is necessary many times repeatedly to run TeX, to look for the result in DVI or PDF file, to gander the TeX output on the terminal, or eventually to have a look in the log-file, and all that action to repeat. In the paper it is show, how this work is made by author. The process '‘'editor-TeX-look' is supported by simple Unix tools: bash script texloop, created by author for these purposes, Xterm terminal and a simple editor, which is able to link to the shortcut key the activation of a system command. The reader could be inspired with the solution and to adapt these tools to his/her own needs. In the paper the function of the texloop script is described, and further the longstanding evolution of the author's relation to text editors is informal elaborated and finally a configuration of Xterm terminal, suitable for the czech environment with both ISO-8859-2 and UTF-8 encoding is introduced. For UTF-8 encoding the TeX format csplain is generated at the end of the paper
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