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Abordagem de martingais para análise assintótica do passeio aleatório do elefante / Martingale approach for asymptotic analysis of elephant random walkMiranda Neto, Milton 20 August 2018 (has links)
Neste trabalho, estudamos o passeio aleatório do elefante introduzido em (SCHUTZ; TRIMPER, 2004). Um processo estocástico não Markoviano com memória de alcance ilimitada que apresenta transição de fase. Nosso objetivo é demonstrar a convergência quase certa do passeio aleatório do elefante nos casos subcrítico e crítico. Além destes resultado, também apresentamos a demonstração do Teorema Central do Limite para ambos os regimes. Para o caso supercrítico, vamos demonstrar a convergência do passeio aleatório do elefante para uma variável aleatória não normal com base nos artigos (BAUR; BERTOIN, 2016), (BERCU, 2018) e (COLETTI; GAVA; SCHUTZ, 2017b). / In this work we study the elephant random walk introduced in (SCHUTZ; TRIMPER, 2004), a discrete time, non-Markovian stochastic process with unlimited range memory that presents phase transition. Our objective is to proof the almost sure convergence for the subcritical and critical regimes of the model. We also present a demonstration of the Central Limit Theorem for both regimes. For the supercritical regime we proof the convergence of the elephant random walk to a non-normal random variable based on the articles (BAUR; BERTOIN, 2016), (BERCU, 2018) and (COLETTI; GAVA; SCHUTZ, 2017b).
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Cinza residual da queima de biomassa do capim elefante (Pennisetum purpureum) como material pozolânico substituto do cimento Portland / Residual ash from biomass of elephant grass (Pennisetum purpureum) as pozzolanic material for partial substitution of Portland cementNakanishi, Erika Yukari 02 August 2013 (has links)
O objetivo do presente estudo foi contribuir para a viabilização do uso da cinza de capim elefante em escala laboratorial como uma pozolana ativa em substituição parcial do cimento Portland, através da obtenção e tratamento da cinza e seu estudo em pastas. O trabalho foi desenvolvido em três etapas. Na etapa 1, denominada \"Obtenção da cinza\", foi realizado o estudo das estruturas do capim elefante, que foi separado em folhas, (colmo + bainha) e planta inteira e para análise da cinza de cada parte. Observa-se na cinza que há um teor elevado principalmente, de sílica e potássio, sendo que o teor de sílica é maior na folha, enquanto o de potássio é maior no (colmo + bainha). Na etapa 2, denominada \"Tratamento da cinza\", foram realizados diferentes tratamentos químicos e térmicos no material, com o intuito de diminuir os teores dos íons alcalinos, e, com isso, aumentar a proporção de SiO2 na cinza final. Foram realizados três tratamentos, sendo T1 tratamento no capim elefante antes da queima, com solução ácida, T2 tratamento na cinza de capim elefante com água quente e T3 tratamento também na cinza com solução ácida. Pode-se observar que houve um aumento no teor de sílica nas cinzas após os tratamentos. E por fim, na etapa 3, denominada \"Estudo das pastas\", procurou-se aplicar a cinza com tratamento T3, através da caracterização das pastas. Foram produzidas cinco pastas diferentes, C (somente cimento), CC (cimento - cinza), CS (cimento - sílica ativa), CHC (hidróxido de cálcio - cinza) e CHS (hidróxido de cálcio - sílica ativa). Foram feitos estudos de caracterização dos materiais, como também ensaios para a avaliação das pastas, dentre eles, resistência à compressão e ensaios para análise da hidratação do cimento. A cinza apresentou ser um material reativo. E, para sua aplicação em pasta, pode-se notar que a resistência à compressão da pasta com 20% de cinza não diferiu significativamente da pasta produzida somente com cimento. Pela avaliação de difração de raios X (DRX), observou-se a diminuição dos picos das fases ferrita, aluminato tricálcico, belita e alita, o que é indicativo do processo da reação. Adicionalmente, pela análise de termogravimetria, constatou-se o consumo de portlandita, com o passar do tempo e a formação dos géis de CSH. Com base nos resultados obtidos nas três etapas descritas neste trabalho, pode-se concluir que a substituição parcial do cimento Portland pela cinza de capim elefante como material pozolânico é tecnicamente possível e viável. / The aim of this study was to contribute to the use of elephant grass ashes, obtained from laboratory scale, as an active pozzolan in partial replacement of Portland cement, by the production and treatment of these ashes and their evaluation study into pastes. The work was developed in three steps. The step 1, entitled: \"Getting Ash\", was carried out to study the structures of elephant grass, which was separated into leaves, (stem + sheath) and the whole plant, and the ashes of each part were analyzed. It is observed that the ash has high content of silica and potassium, whereas the silica content is higher in the leaf part, while potassium is highest in the (stem + sheath) region. In step 2, entitled \"Treatment of the ash\" there were carried out different thermal and chemical treatments on the material, to reduce the concentration of alkali ions and thereby increase the proportion of SiO2 in the ash. Three treatments were carried out: T1, treatment in the elephant grass before burning, with acid solution; T2, treatment in the elephant grass ash with hot water and; T3, treatment also in the ash with acid solution. It can be observed an increase in the silica content in the ashes after of the treatments. Finally, the step 3 activities, entitled \"Study of pastes\", attempted to apply the ash with T3 treatment, by the characterization of the pastes. Five different pastes were produced, C (cement only), CC (cement - ash), CS (cement - silica fume), CHC (calcium hydroxide - ash) and CHS (calcium hydroxide - silica fume). There were made studies for the characterization of the materials, as well as, the tests for the evaluation of the pastes, such as compressive strength tests and the analyses to measure the hydration of the cement. The ash under consideration showed to be a reactive material. For its application in the paste, it can be noted that the compressive strength of the paste with 20% of the ash did not differ significantly the paste produced with only cement. For the evaluation of X-ray diffraction (XRD), it was observed a decrease of the peaks of the ferrite phases, tricalcium aluminate, alite and belite, which is indicative of the reaction process. In the thermogravimetric analysis, it was observed the consumption of portlandite, in the course of time, and the formation of the CSH. Based on the results obtained in the three steps described in this work, it can be concluded that the partial replacement of Portland cement by elephant grass ash as pozzolanic material is technically possible and viable.
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A comparative cognition perspective on the production and use of visual signals by African savannah elephants (Loxodonta africana)Smet, Anna F. January 2015 (has links)
Elephants' complex societies, well-developed communication systems, evolutionary history and close working relationship with humans make them an important species for studies of cognition but research on elephant cognition is sparse. In this thesis I aim to illuminate the social cognition involved in the interpretation and production of visual signals by African elephants (Loxodonta africana). My results are intended to contribute to the cross-species literature on social cognition and help to elucidate wild elephant social behaviour. I studied captive elephants, housed at an elephant-back safari company in Victoria Falls, and wild elephants in Hwange National Park, both in Zimbabwe. Wild elephants display a vast array of postures, actions and signals. I found that elephants recognise visual attentiveness in others when they signal silently, producing more signals when their audience can see them, and using the body and face orientation of an audience to judge their attention. When responding to typically human visual signals, elephants immediately responded correctly to deictic gestures, including variants of pointing that they were unlikely to have already experienced. These results indicate elephants' astonishing sensitivity to even subtle social cues. I found no indication that elephants reason about mental states such as false beliefs, or rationality; however, limitations of the experimental design meant I was unlikely to find such an ability even if it is present in elephants. Furthermore, I discovered that elephants have a form of referential indication in their natural communication in the wild. Elephants match their direction of attention with a type of trunk action produced by a group member. Attending to human-like signals, and interpreting them as communicative is an advantage for any animal working with humans and that ability might explain the choice of species that are ancestors of today's domestic animals.
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Manejo do nitrog?nio e emiss?o de gases de efeito estufa na produ??o de capim-elefante para bioenergia / Nitrogen management and greenhouse gases emissions in elephant grass production for bioenergyMorais, Rafael Fiusa de 22 December 2011 (has links)
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Previous issue date: 2011-12-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Elephant grass is highly efficient in dry matter accumulation and has suitable quality
parameters for energy production. The use of elephant-grass biomass depends on the energy
balance and the greenhouse gas emissions associated with management practices used for
biomass for energy production. Generally, the contribution of biological nitrogen fixation
serves less than half the crop N demand, it is necessary to replace the N removed from the
soil. N fertilization is usually recommended, however the impact on N2O emissions to
atmosphere is unknown. The aim of this study was to carry out studies to measure N fertilizer
losses in the form of ammonia volatilization and N2O emissions. Ammonia volatilization was
evaluated since it is related to indirect N2O emissions. The effects of nitrogen doses, sources
and application forms were studied, to identify the best pathway to provide nitrogen for the
crop, with less impact on N2O emissions. The N2O emissions resulting from the soil tillage
and four urea fertilizer doses (40, 80, 120 and 160 kg N ha-1) were evaluated. Different
nitrogen fertilizer sources (urea and ammonium sulfate) and urea application forms
(incorporated or surface) compared with ammonium sulfate, respectively, and green manure
were evaluated, compared to application of urea and polymer-coated urea, to evaluate the
nitrogen efficiency by the plants and soil N2O emissions. The results showed that nitrogen
fertilization is essential to reach high biomass yield of elephant grass. N2O emissions were
higher with urea application than with ammonium sulfate, with no effect on the quantity of
urea incorporated. The use of green manure resulted in higher N2O emissions compared to
urea. The NH3 volatilization losses ranged from 40 to 60% when urea was applied and 11%
with the application of ammonium sulfate. The NH3 volatilization losses were 35% lower
when urea was incorporated, resulting in higher elephant grass biomass yield. The polymercoated
urea resulted in a decrease of 6% in the NH3 volatilization losses. Nitrogen fertilizer is
essential to reach high elephant grass biomass yield, and the environmental impact caused by
this practice may be reduced by changing the source and form of the fertilizer application. / O capim-elefante est? entre as gram?neas de maior capacidade de acumula??o de mat?ria seca,
possuindo tamb?m caracter?sticas qualitativas favor?veis para a produ??o de energia. A
sustentabilidade de seu uso depende basicamente de seu balan?o energ?tico e da quantidade
de gases de efeito estufa decorrentes das pr?ticas de manejo, do cultivo e do uso de sua
biomassa. Geralmente, a contribui??o da fixa??o biol?gica de nitrog?nio atende a menos do
que metade da demanda de N da cultura, sendo necess?rio repor o N retirado do sistema. O
uso de fertilizantes nitrogenados ? a op??o mais recomendada, por?m n?o se sabe o impacto
quanto as emiss?es de N2O para a atmosfera. O objetivo geral desse estudo foi realizar
experimentos que permitissem medir as perdas de N de fertilizantes na forma de volatiliza??o
de am?nia e emiss?o de N2O. A volatiliza??o de am?nia foi avaliada por estar relacionada as
emiss?es de N2O indiretas. Tamb?m se estudaram os efeitos de doses, fontes e formas de
aplica??o de N, visando identificar a melhor forma de fornecer nitrog?nio para a cultura, com
menor impacto nas emiss?es de N2O. Foram avaliadas as emiss?es de N2O decorrentes da
etapa de preparo do solo e da aplica??o de quatro doses de nitrog?nio fertilizante na forma de
ureia (40, 80, 120 e 160 kg de N ha-1). Foram avaliadas diferentes fontes de N fertilizante
(ureia e sulfato de am?nio) e formas de aplica??o da ureia (incorporada ou a lan?o) em
compara??o com sulfato de am?nio, respectivamente, e aduba??o verde, em compara??o a
aplica??o de ureia comum e revestida com pol?meros, sobre a efici?ncia do uso do N pelas
plantas e sobre as emiss?es de N2O do solo. Os resultados mostraram que a aduba??o
nitrogenada ? essencial para alcan?ar elevadas produtividades de biomassa em capimelefante.
As emiss?es de N2O foram maiores com a utiliza??o da ureia do que com a
utiliza??o do sulfato de am?nio, n?o havendo efeito da incorpora??o da ureia. A utiliza??o da
aduba??o verde acarretou em maiores emiss?es de N2O quando comparada a ureia. As perdas
por volatiliza??o de NH3 variaram entre 40 a 60% do N aplicado na forma de ureia, e de 11%
quando se utilizou sulfato de am?nio. As perdas por volatiliza??o de NH3 foram 35% menores
quando a ureia foi enterrada, o que acarretou maiores ganhos de produtividade pelo capimelefante.
A ureia revestida com pol?meros acarretou em diminui??o de 6 % das perdas por
volatiliza??o de NH3. A utiliza??o do fertilizante nitrogenado ? essencial para alcan?ar
elevadas produtividades de biomassa do capim-elefante, e o impacto ambiental causado por
essa pr?tica pode ser reduzido em fun??o da fonte e da forma de aplica??o do fertilizante.
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An Evaluation of Deterrent Methods Utilized to Prevent Crop Raiding by African Elephants (Loxodonta Africana) in the Kasigau Wildlife Corridor, KenyaVon Hagen, Rebecca Lynn 01 July 2018 (has links)
Escalating human elephant conflict (HEC) continues to be a contributing factor
towards elephant decline, and crop raiding is the most common form of negative
human-elephant interactions. For communities that cannot reverse or prevent crop
raiding, it is necessary to contain HEC events through deterrent measures. Few
deterrent measures exist that combine practicality and affordability while also
preventing habituation by elephants. This project focused on comparing the efficacy of
deterrent methods to assess which was the most successful at preventing elephants
from entering crops in the farming community of Sasenyi, Kenya. In this paired-control
study, four deterrent methods were evaluated: acacia fences, chili-pepper fences, a
new metal strip fence, and a combination of a chili and metal strip fence. Of the over
400 visits by elephants to individual fields containing crops recorded during two field
seasons, elephants entered farmer fields in the experimental area on 33 occasions
(<10%). Analysis of incidents when elephants approached at less than 50 m revealed
that the chili + metal fence and the metal fence were significantly more effective than
no deterrent. Following further verification of its effectiveness, this new deterrent
method could be a powerful new tool to alleviate elephant crop raiding and reduce HEC.
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Analysis and Classification of Sounds Produced by Asian Elephants (Elephas Maximus)Glaeser, Sharon Stuart 01 January 2009 (has links)
Relatively little is known about the vocal repertoire of Asian elephants (Elephas maximus), and a categorization of basic call types and modifications of these call types by quantitative acoustic parameters is needed to examine acoustic variability within and among call types, to examine individuality, to determine communicative function of calls via playback, to compare species and populations, and to develop rigorous call recognition algorithms for monitoring populations.
This study defines an acoustic repertoire of Asian elephants based on acoustic parameters, compares repertoire usage among groups and individuals, and validates structural distinction among call types through comparison of manual and automated classification methods. Recordings were made of captive elephants at the Oregon Zoo in Portland, OR, USA, and of domesticated elephants in Thailand. Acoustic and behavioral data were collected in a variety of social contexts and environmental noise conditions. Calls were classified using perceptual aural cues plus visual inspection of spectrograms, then acoustic features were measured, then automated classification was run. The final repertoire was defined by six basic call types (Bark, Roar, Rumble, Bark, Squeal, Squeal, and Trumpet), five call combinations and modifications with these basic calls forming their constituent parts (Roar-Rumble, Squeal-Squeak, Squeak train, Squeak-Bark, and Trumpet-Roar), and the Blow. Given the consistency of classifications results for calls from geographically and socially disparate subject groups, it seems possible that automated call detection algorithms could be developed for acoustic monitoring of Asian elephants.
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Predicting Parturition in a Long-Gestating Species: Behavioral and Hormonal Indicators in the Asian Elephant (Elephas maximus)Velonis, Heather Kelly 08 June 2017 (has links)
Captive populations of Asian elephants (Elephas maximus) in North America are not self-sustaining, and increasing reproductive success within captive populations is a high priority. The ability to accurately predict parturition can have a direct impact on elephant welfare. Elephants in captivity often require significant preparation and management throughout the birthing process, and complications during labor and delivery can necessitate immediate intervention, including stillbirth, protracted labor, maternal aggression towards a newborn calf, and dystocia. Being able to predict when parturition will commence can ensure appropriate staff is available and adequate monitoring is performed. Routine endocrine sampling can be used to predict parturition in Asian elephants, with a drop in progesterone (P4) to baseline levels signaling parturition in 2-5 days. However, we determined this method is not without limitations, and it is not used in all institutions that house elephants. As changes in hormones regulate and alter behaviors, we investigated behavioral indicators as an additional management tool for predicting parturition, a time of drastic hormone changes. We conducted a study of five pregnancies in Asian elephants at the Oregon Zoo, U.S.A, and Taronga Zoo, Australia, between 2008 and 2012.
In Chapter 2, I evaluated progesterone (P4) and cortisol levels across three time periods: Baseline; Pre, (the week preceding the drop in P4); and Post, (the period after the P4 drop). Levels of P4 were significantly lower, and levels of cortisol were significantly higher in the days just prior to parturition. I found considerable intra- and inter-individual variation in both endocrine profiles, which can make endocrine assessments difficult to interpret in real time.
In Chapter 3, I investigated whether behaviors in the preparturition period could be predictive of impending parturition in the Asian elephant. ANOVA results indicated a significant difference in the amount of time that elephants spent walking backwards across three time periods (F(2) = 3.723, p = 0.033), with the behavior increasing as parturition approached. These results were supported by a non-parametric Kruskal- Wallis. Using a generalized linear mixed model (GLMM), I found that as P4 levels decrease, walking backwards behavior significantly increases.
In Chapter 4, I evaluated investigative trunk behaviors, or "trunk checks", directed towards the temporal gland near the ear, mammary glands, vulva and anus of the pregnant dam. Investigative behaviors included both self-directed behaviors and those sent from herd mates towards the pregnant dam. Self-directed behaviors are most likely associated with physical changes in the pregnant dam, such as using the trunk to pull on swollen teats. Other-directed behaviors may stem from chemo-sensory signaling or other types of communication between herd mates, such as detecting changes in progesterone or cortisol. I ran GLMM and found that four trunk-check behaviors varied significantly with P4 and/or cortisol profiles. These were: self-checks of mammary glands increased with decreasing P4 levels; herd-mate-checks of mammary glands increased with decreasing P4 levels; self-checks of vulva increased with decreasing P4 levels and increasing cortisol levels; herd-mate-checks of anus increased with increasing cortisol levels.
In Chapter 5, I evaluated activity budget behaviors in the pregnant elephants. Generalized comparisons were made to published activity budgets of typical captive Asian elephants. I report that activity budgets are within the range of normal activity, though I note a high level of inter-individual variation. In addition, I compared two sampling techniques, including one-zero and instantaneous sampling, that were used for activity budget data collection. I discuss the different results obtained by each sampling technique.
These results are a very promising indication that behaviors, including walking backwards and multiple trunk-check behaviors, are changing over time or with parturition-related hormone profiles. We recommend that keepers, veterinary staff, and other observers that are familiar with the regular behavioral repertoire of a pregnant female should pay close attention to these highlighted behaviors. Keeping track of these behaviors, especially in conjunction with P4 and cortisol tracking, can help staff refine existing windows of expected parturition.
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Den Avvikande Individen: Identitet och Samspel : En analys av The Elephant Man och MaskKarlsson, Maria January 2013 (has links)
Många individer är inte accepterade i samhället på grund av att de avviker. Detta är ett stort problem då de riskerar utanförskap och sämre livskvalitet. Vad jag därmed kommer att studera i denna uppsats är hur avvikande individer bemöts i samhället och hur de svarar på detta bemötande. De filmer som jag kommer att utgå ifrån i analysen är The Elephant Man (1980) av David Lynch och Mask (1985) av Peter Bogdanovich. Jag kommer sedan att använda mig av socialpsykologin som teori för att kunna analysera hur och varför detta sker. Då jag tolkar de scener jag valt ut kommer jag att använda mig av Hermeneutiken som vetenskaplig metod. I mitt arbete har jag kommit fram till att den avvikande individen bemöts olika i samhället beroende på de människor som bor där och vilken tid filmen skildrar. Vissa människor väljer att se individen utifrån kognitivt igenkännande, andra väljer genom socialt igenkännande. De kan se på den avvikande individen vara genom rädsla men också genom sympati, altruism. Dessa baseras i sin tur på de sociala normer som skapas i de samhällsgrupper som existerar. Den avvikande individens jag-identitet kan därmed påverkas negativt av andra människors handlingar. De väljer att svara på detta på olika sätt, antingen genom att försöka dölja sig, eller genom att stå emot och kämpa. De intar dock roller eller mimicry för att passa in.
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The Role Volunteer Tourism Plays in Conservation: A Case Study of the Elephant Nature Park, Chiang Mai, ThailandRattan, Jasveen January 2009 (has links)
This study examined the role volunteer tourism played in the conservation of elephants in Chiang Mai, Thailand. A case study was conducted to determine whether volunteer tourism at the Elephant Nature Park (ENP) had an effect on elephant conservation. Specifically, this study looked at how volunteer tourism and the ENP had an impact on: non-volunteer tourists, elephants, the local economy, and government policy. Mixed methods were used to attain the data in this study. Self-administered questionnaires were created to determine the impact volunteer tourism had on non-volunteer tourists. Results showed an increase in non-volunteer tourists’ awareness of elephant tourism, volunteer tourism and elephant conservation during the time they spent at the park. Self-administered questionnaires were also used to determine whether members of the local community felt they were receiving economic or social benefits from volunteer tourism and the ENP. The data showed that community participants felt they were receiving both economic and social benefits but their responses varied depending on sex, age, and how long they had lived in the region. Semi-structured interviews were also conducted to determine the role the ENP had on the conservation of elephants in Thailand and government policy. Interviewees consisted of experts in the industry who were knowledgeable about elephant tourism, volunteer tourism, and the ENP. The data indicated that the ENP created awareness about elephant conservation issues with non-volunteer tourists, volunteers, the community, and government officials. However, the ENP did not have any measureable effect on government policy. The model of volunteer tourism utilized by the Elephant Nature Park has been shown to be effective in conserving the domestic elephant and in creating awareness about domestic elephant conservation issues in Thailand.
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Fodertillgång och stereotypa beteenden under natten hos Asiatisk elefant (Elephas maximus)Olby, Sara January 2011 (has links)
Animals in zoos live in more barren environments than their conspecifics in nature. In nature, elephants spend more than 75 % of the day foraging and have been observed lying down two hours during night. Stereotypies are common in many different species in zoos. Stereotypic behaviors may constitute up to 50 % of the daily activity budget of zoo elephants. Modern zoos try to reduce stereotypic behaviors by means of environmental enrichment. Three elephant cows at Kolmårdens Djurpark were observed during night to map their nocturnal behaviors and see how they changed with feeding enrichment. The elephants were lying down on their sides 25 % of the time observed. With feeding enrichment offered in the morning, the stereotypies was reduced in one individual from 43 % to 13 % (P<0.01) and the foraging was increased in two individuals from 45 % to 80 % (P<0.01) and from 45 % to 64 % (P<0.05). Increased food access increased foraging behavior and as environmental enrichment was able to reduce the stereotypic behaviors in these Asian elephant.
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