O uso de Internet para a distribuição de fluxos de vídeo tem se mostrado uma tendência atual e traz consigo grandes desafios. O alicerce sobre qual a Internet está fundamentada, comutação por pacotes e arquitetura cliente-servidor, não proporciona as melhores condições para este tipo de serviço. A arquitetura P2P (peer-to-peer) vem sendo considerada como infraestrutura para a distribuição de fluxos de vídeo na Internet. A idéia básica da distribuição de vídeo com o suporte de P2P é a de que os vários nós integrantes da rede sobreposta distribuem e encaminham pedaços de vídeo de forma cooperativa, dividindo as tarefas, e colocando à disposição da rede seus recursos locais. Dentro deste contexto, é importante investigar o que ocorre com a qualidade do serviço de distribuição de vídeo quando a infraestrutura provida pelas redes P2P é contaminada por nós que não estejam dispostos a cooperar, já que a base desta arquitetura é a cooperação. Neste trabalho, inicialmente é feito um estudo para verificar o quanto a presença de nós não-cooperativos pode afetar a qualidade da aplicação de distribuição de fluxo de vídeo em uma rede P2P. Com base nos resultados obtidos, é proposto um mecanismo de incentivo à cooperação para que seja garantida uma boa qualidade de vídeo aos nós cooperativos e alguma punição aos nós não-cooperativos. Os testes e avaliações foram realizados utilizando-se o simulador PeerSim. / Using the Internet for video stream is becoming a trend, but it brings many challenges. The foundation upon which the Internet is based, packet switching and client-server architecture, is not suitable for this type of service. P2P (peer to peer) architecture is being considered as an infrastructure for video streams on the Internet. The basic idea is that the several members of the overlay network cooperate in the task of distributing and fowarding video chunks, making available their local resources to the network. Within this context, it is important to investigate what happens to the quality of service of the video distribution when the infrastructure provided by the P2P network is contaminated with free-riding nodes, which are not willing to cooperate, since the basis of this architecture is cooperation. In this work, study is initially carried out to check how the presence of uncooperative nodes can affect the quality of the distribution application of video streaming on a P2P network. Based on these results, a mechanism is proposed to encourage cooperation in order to be guaranteed a video with good quality to the cooperative nodes and some punishment for those uncooperative. The tests and evaluations were performed using the PeerSim simulator.

La connaissance des conditions psychosociologiques dans lesquelles les entrepreneurs décident de la fin de leur carrière renvoie à des enjeux particulièrement cruciaux pour les chercheurs et les praticiens du conseil. Les conséquences de l’arrêt de l’activité entrepreneuriale sont en effet notables à la fois aux plans individuel, macro-économique car liés à la problématique de la cession-transmission de l’entreprise et sociaux au regard des emplois à préserver (Detienne, 2010). La finalité générale de cette thèse était d’éclairer les facteurs psychosociologiques complexes qui sous-tendent la décision du départ à la retraite dans la population des dirigeants propriétaires. Pour ce faire, le présent travail doctoral visait deux objectifs majeurs. Le premier était de développer un inventaire fiable permettant l’analyse précise de la nature et de la structure des raisons conduisant les entrepreneurs à prendre la décision de mettre fin à leur carrière professionnelle. Trois études distinctes portant sur 442 participants au total ont permis la création et la validation de l’Inventaire des Raisons du Processus Décisionnel du départ à la Retraite des Entrepreneurs (IRPDRE), à partir du modèle Push Pull Anti-push Anti-pull de Mullet, Dej, Lemaire, Raïff, & Barthorpe (2000). Le second objectif visé dans l’étude 4 portait sur le test auprès d’un échantillon de 271 participants d’un modèle des déterminants individuels de la perception des raisons sous-tendant le processus décisionnel de l’arrêt de la carrière chez les entrepreneurs. Cette modélisation incluait également l’examen des liens entre l’évaluation des diverses raisons et l’intention de partir à la retraite des entrepreneurs. Au final, les résultats obtenus dans ce programme de recherches ont permis de proposer un outil multidimensionnel fiable permettant d’évaluer finement la perception complexe des facteurs psychosociologiques à l’origine de la prise de décision du désengagement professionnel des entrepreneurs. Ils ont aussi conduit à une meilleure compréhension des différences interindividuelles lors de la prise de décision de fin de carrière dans cette population. / Understanding the psychosociological conditions of entrepreneurs’ decisions to retire is an important issue for researchers and practitioners. Indeed, the consequences of entrepreneurs’ decisions to retire are important at three levels: individual, macroeconomic in that their retirement is linked to the disposal and transfer of their business, and social in that it affects employment (Detienne, 2010). The overall purpose of this doctoral research was to analyze the psychosociological factors underlying the retirement decision in this specific population. The study had two main objectives. The first was to provide researchers and practitioners with an original and reliable self-report questionnaire to assess the nature and form of the reasons underlying the retirement decision process. Three studies, with a total of 442 participants, were conducted to develop and validate the Reasons for Entrepreneurs’ Retirement Decision Inventory (RERDI), based on the Push Pull Antipush Anti-pull view (Mullet, Dej, Lemaire, Raïff, & Barthorpe, 2000). A fourth study involving 271 participants was carried out to achieve the second objective, which was to test a model of individual determinants of the reasons underlying the retirement decision process. This model also examined the relationships between the evaluation of the reasons and the intention to retire. Finally, the results of these studies allow us to propose a multidimensional and reliable tool to assess in detail the complex perception of the psychosociological factors underlying entrepreneurs’ decisions to retire. The results also provide a better understanding of interindividual differences in this retirement decision.

O uso de Internet para a distribuição de fluxos de vídeo tem se mostrado uma tendência atual e traz consigo grandes desafios. O alicerce sobre qual a Internet está fundamentada, comutação por pacotes e arquitetura cliente-servidor, não proporciona as melhores condições para este tipo de serviço. A arquitetura P2P (peer-to-peer) vem sendo considerada como infraestrutura para a distribuição de fluxos de vídeo na Internet. A idéia básica da distribuição de vídeo com o suporte de P2P é a de que os vários nós integrantes da rede sobreposta distribuem e encaminham pedaços de vídeo de forma cooperativa, dividindo as tarefas, e colocando à disposição da rede seus recursos locais. Dentro deste contexto, é importante investigar o que ocorre com a qualidade do serviço de distribuição de vídeo quando a infraestrutura provida pelas redes P2P é contaminada por nós que não estejam dispostos a cooperar, já que a base desta arquitetura é a cooperação. Neste trabalho, inicialmente é feito um estudo para verificar o quanto a presença de nós não-cooperativos pode afetar a qualidade da aplicação de distribuição de fluxo de vídeo em uma rede P2P. Com base nos resultados obtidos, é proposto um mecanismo de incentivo à cooperação para que seja garantida uma boa qualidade de vídeo aos nós cooperativos e alguma punição aos nós não-cooperativos. Os testes e avaliações foram realizados utilizando-se o simulador PeerSim. / Using the Internet for video stream is becoming a trend, but it brings many challenges. The foundation upon which the Internet is based, packet switching and client-server architecture, is not suitable for this type of service. P2P (peer to peer) architecture is being considered as an infrastructure for video streams on the Internet. The basic idea is that the several members of the overlay network cooperate in the task of distributing and fowarding video chunks, making available their local resources to the network. Within this context, it is important to investigate what happens to the quality of service of the video distribution when the infrastructure provided by the P2P network is contaminated with free-riding nodes, which are not willing to cooperate, since the basis of this architecture is cooperation. In this work, study is initially carried out to check how the presence of uncooperative nodes can affect the quality of the distribution application of video streaming on a P2P network. Based on these results, a mechanism is proposed to encourage cooperation in order to be guaranteed a video with good quality to the cooperative nodes and some punishment for those uncooperative. The tests and evaluations were performed using the PeerSim simulator.

Submitted by Morgana Silva (morgana_linhares@yahoo.com.br) on 2016-07-26T18:10:50Z No. of bitstreams: 1 arquivototal.pdf: 2752063 bytes, checksum: 886fc73f7f66099f1e033937798f6b7e (MD5) / Made available in DSpace on 2016-07-26T18:10:50Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2752063 bytes, checksum: 886fc73f7f66099f1e033937798f6b7e (MD5) Previous issue date: 2016-02-29 / This paper presents a block diagram modeling of a grid-independent photovoltaic power generation system, including the steps of DC regulation, voltage inversion, and control system based on dynamic simulations in Simulink / Matlab® exclusively using the built-in blocks available in its library. A well-known technique in literature called MPPT (maximum power point tracking) was used for tracking the maximum power of the photovoltaic generation. However, the control that was used to maintain a constant output voltage of the Push-Pull is based on a method that is similar to the MPPT, which configures a novelty of this research. The integration of modeling the entire PV system with these control systems is carried out in Simulink for investigaton and production of simulation results. An experimental platform that includes an emulator of photovoltaic panels, a 1 kW Push-Pull converter, a three-phase inverter with three arms and a hydraulic load constituided by a motor-pump was built in the laboratory. The experimental results corroborate the methodology that was used. / Este trabalho apresenta uma modelagem em diagramação de blocos de um sistema de geração de energia fotovoltaico isolado, incluindo as etapas de regulação CC, inversão de tensão e sistema de controle com base em simulações dinâmicas no ambiente Simulink/Matlab® utilizando, exclusivamente, os blocos built-in disponíveis em sua biblioteca. Uma técnica bem conhecida na literatura foi utilizada para o rastreio da máxima potência da geração fotovoltaica. No entanto, o controle utilizado para manter a tensão de saída constante do Push-Pull é baseado num método similar ao do rastreio da máxima potência, o que configura uma novidade deste trabalho. A integração da modelagem de todo o sistema fotovoltaico com estes sistemas de controle é realizada no ambiente Simulink para averiguação e produção dos resultados de simulação. Uma plataforma experimental que inclui um emulador de painéis fotovoltaicos, um Push-Pull de 1 kW de potência, um inversor trifásico de três braços e uma carga hidráulica constituída por um motobomba foi construída em laboratório. Os resultados experimentais corroboram a metodologia utilizada.

Les processus microbiens ont une importance déterminante dans la dynamique des processus réactifs dans les eaux souterraines. La compréhension de la variabilité spatiale et temporelle de ces phénomènes, et le développement de méthodes expérimentales de terrain, ouvrent de nouveaux champs de recherches et d'applications allant de la remédiation des aquifères contaminés à la compréhension des grands cycles biogéochimiques naturels. Dans le premier volet de cette thèse nous présentons des observations de terrain permettant de comprendre le rôle des fractures sur la formation d'un ''hotspot'' d'activité microbienne en profondeur. Du fait de leur forte réactivité, ces ''hotspots'' peuvent dominer la dynamique biogéochimique des milieux souterrains, malgré leur faible extension spatiale. Nous avons ainsi analyser les conditions de formation d'un tapis microbien par des bactéries ferro-oxydantes à 60 mètres de profondeur sur l'observatoire de Ploemeur (réseau H+) alors que ces phénomènes ont été observé jusqu'à présent en surface. Les résultats de cette étude montrent que des circulations hétérogènes, liées à la structure des milieux fracturés, créent des zones mélanges entre des eaux riches en fer et des eaux oxygénées, à l'origine de ce hotspot microbien. Le deuxième volet de ce travail de thèse a été consacré au développement d'une méthode innovante pour la mesure en continu de l'activité microbienne dans les eaux souterraines. La méthode est basée sur l'utilisation de la Fluoréscéine DiAcétate (FDA) dont le produit de réaction peut être mesuré en continu par un fluorimètre de terrain. Après avoir testé et validé les protocoles sur des solutions enzymatiques et des eaux naturelles en laboratoire, nous avons mis en œuvre cette technique sur le terrain au cours d'expériences de traçages réactifs. Un modèle cinétique nous a permis d'approcher les résultats obtenus en laboratoire, et de comparer nos résultats de terrain aux calibrations effectuées in vitro. Cette méthode ouvre ainsi de nouvelles perspectives pour la caractérisation des processus biogéochimiques sur le terrain. / Microbial processes play a key role in controlling biogeochemical reactivity in groundwater. The understanding of the spatial and temporal variability of these phenomena and the development of novel experimental field methods, has opened new fields of research and applications, ranging from groundwater remediation to understanding of global biochemical cycles. In the first part of this thesis, we present field observations providing new insights on the role of fractures in the formation of a hotspot of microbial activity. Because of their large reactivity, these hotspots can dominate the biogeochemical dynamics of subsurface systems, despite their small spatial extent. We have thus analyzed the conditions for the formation of a microbial mat composed of iron-oxidizing bacteria at 60 meters depth in the Ploemeur fractured rock observatory (H+ network) while these phenomena are usually observed at the surface. These results show that heterogeneous flowpaths, linked to the structure of fractured media, create mixing zones between iron rich water and oxygen rich water, at the origin of the microbial hotspot. The second part of this work was devoted to the development of a novel method for a continuous measurement of microbial activity in groundwater. The method is based on the use of Fluorescein DiAcetate (FDA) whose product of reaction can be measured continuously by a field fluorimeter. After testing and validating protocols in the lab on enzymatic solutions and natural water, we have implemented this technic in the field in reactive tracer test experiments. A kinetic model allowed us to interpret the lab results, and to compare them to the field kinetics. This method thus opens new perspectives for the characterization of biogeochemical processes in the field.

Au sein des écosystèmes, les Composés Organiques Volatils (COVs) émis par les plantes jouent un rôle majeur dans les interactions trophiques. Ces signaux olfactifs vont renseigner les insectes phytophages sur la présence de leurs hôtes mais permettent aussi de recruter les ennemis naturels. Il a été montré que certains de ces composés pouvaient être utilisés pour manipuler le comportement des insectes phytophages s’attaquant aux cultures. La stratégie push-pull, vise à combiner des stimuli positifs et négatifs pour un insecte ravageur afin de le repousser d’une culture tout en l’attirant sur une plante piège implantée en périphérie du champ où il pourra être contrôlé. L’objectif de cette thèse est d’améliorer notre compréhension et nos connaissances sur la manipulation de la communication chimique entre les plantes et les insectes phytophages à l’aide de COVs de synthèse et de préférence d’hôte afin de mettre en place sur le terrain une stratégie de type push-pull pour protéger une culture de la mouche du chou (Delia radicum). Dans un premier chapitre, nous montrons que dans un système push-pull composé (i) de diffuseur de diméthyldisulfure DMDS (composante push) et (ii) d’une bordure de choux chinois supplémenté avec de l’acétate d’hexenyl (Z-3-HAC) (composante pull), il est possible de modifier fortement le comportement d’oviposition de D. radicum sans impacter de façon négative ses principaux ennemis naturels. Les limites agronomiques et d’utilisation du DMDS atteintes, nous avons recherché d’autres COVs ayant un effet répulsif. Lors d’une seconde expérimentation en push-pull, l’eucalyptol (1-8 cinéol) à permis de réduire le nombre de pupes de D. radicum retrouvées aux pieds des plants de brocoli de 60%. Suite à ce résultat encourageant, nous avons qualifié au laboratoire l’effet inhibiteur de ce monoterpène sur l’oviposition de la mouche du chou et en avons conclu qu’il permet de masquer le bouquet de COVs attractif d’un hôte. L’efficacité de la composante push étant fortement liée à la diffusion des COVs, nous avons ensuite testé au laboratoire et sur le terrain un nouveau type de diffuseur à base de cires végétales, permettant d’émettre l’eucalyptol de manière passive mais régulière pendant plusieurs semaines. L’étude réalisée montre le fort potentiel du diffuseur qui est à la fois bon marché, facile d’utilisation et fiable en terme de diffusion, permettant ainsi d’envisager son utilisation dans des stratégies de lutte intégrée à grande échelle. Parallèlement à l’étude de la composante push, nous avons cherché à améliorer l’efficacité de la composante pull. Le chou chinois (Brassica rapa) permet grâce à sa forte attractivité de capter et détourner la pression de phytophagie de la culture d’intérêt. Nous montrons qu’au sein de sa grande diversité, certaines variétés comme Richi (appartenant à la sous espèce pekinensis) sont préférentiellement attaqué par la mouche du chou, ce qui en fait de bons candidats au développement d’une composante pull efficace. A la lumière de la bibliographie et de nos résultats, nous proposons une réflexion générale sur le système étudié. Ainsi, nous concluons que, au moins dans le cas de la mouche du chou, les COVs ne peuvent probablement pas être les seuls outils considérés dans le développement d’une stratégie push-pull. / Within ecosystems, Volatile Organic Compounds (VOCs) emitted by plants play a major role in trophic interactions. These olfactive signals will inform phytophagous insects about the presence of their hosts, but they also allow to recruit their natural enemies. It has been shown that some of these compounds could be used to manipulate the behaviour of insect crop pests. The push-pull strategy aims at combining positive and negative stimuli to push a pest out of a crop and lure it into a trap crop located in the periphery of the field, where it can be controlled. The objective of this thesis is to improve our understanding and our knowledge on the manipulation of chemical communication between plants and phytophagous insects, using synthetic VOCs and host preference as tools, to protect a crop against the cabbage root fly (Delia radicum). In a first chapter, we show that in a push-pull made of (i) DMDS dispensers as a push component and (ii) chinese cabbage strips supplemented with hexényl acetate (Z-3-HAC) as a pull component, it is possible to strongly reduce oviposition behaviour in D. radicum without impacting its natural enemies. Agronomic limits to the use of DMDS led us to search for other repulsive VOCs. In a second push-pull field experiment, using eucalyptol (1-8 cinéol), reduced by 60% the number of D. radicum pupae produced in the crop. This encouraging result led us to characterize the inhibition effect of this monoterpene in the lab and concluded that it allows to mask the attractive blend of VOCs released by the host. The efficiency of the push component being strongly linked to that of the VOC diffusion, we have then tested both in the laboratory and in the field a new kind of dispenser made of vegetal waxes, allowing to diffuse eucalyptol passively but regularly during several weeks. This study shows the good potential of this device, which is affordable, easy to use and reliable in terms of diffusion, in integrated pest management strategies at a large scale. In parallel of our studies on the push component, we have also sought to increase the efficiency of the pull component. Thanks to its strong attractivity toward D. radicum, Chinese cabbage (Brassica rapa), allows to divert pest pressure from the cash crop. We show that within its important genetic diversity, some cultivars such as Richi (of the pekinensis subspecies) are preferentially attacked by D. radicum, which makes them good candidates to develop an efficient pull component. Using both the literature and our own results, we finally propose a general discussion on the system studied. We conclude that, at least in the case of the cabbage root fly, VOCs are probably not the sole tools to consider when trying to develop a push-pull strategy.

Der Gründung von neuen Unternehmen wird seit einigen Jahren sowohl von Wissenschaftlern als auch von Politikern eine wachsende Aufmerksamkeit zuteil. So sind diese überzeugt, dass die Gründungsaktivität einen positiven Beitrag für die wirtschaftliche Entwicklung eines Landes leistet. Schon aus dieser Überzeugung heraus werden in Deutschland Gründungen mit unterschiedlichsten Unterstützungsleistungen gefördert. Einerseits werden z. B. mittels Gründungszuschuss und Einstiegsgeld Gründungen aus Arbeitslosigkeit unterstützt mit dem hauptsächlichen Ziel, die Arbeitslosigkeit der betreffenden Person zu beenden oder zu vermeiden (vgl. Sozialgesetzbuch Drittes Buch - Arbeitsförderung - § 57 und Sozialgesetzbuch Zweites Buch - Grundsicherung für Arbeitsuchende - § 29). Andererseits fördert der Staat beispielsweise mittels der EXIST-Programme innovative Gründungen bzw. Gründungen aus Hochschulen und Forschungseinrichtungen, von denen auch erwartet wird, dass sie in größerem Umfang Arbeitsplätze schaffen, Effizienz sicherstellen, den Strukturwandel beschleunigen, für mehr Vielfalt am Markt sorgen und nicht zuletzt den Wettbewerb steigern und damit das Wachstum einer Volkswirtschaft vorantreiben. Sicherlich sind aber von den meisten Gründungen keine „Wachstumswunder“ zu erwarten, vor allem nicht von Gründungen aus Arbeitslosigkeit. Ein Großteil der Gründer sichert mit der Selbstständigkeit nur das jeweils eigene Einkommen. Viele Gründungen bleiben klein, schaffen keine oder kaum Arbeitsplätze und tragen nur in äußerst geringem Maße zum Wachstum einer Volkswirtschaft bei. Ein erstes Ziel dieser Arbeit ist es, Gründungen aus Beschäftigung und Gründungen aus Arbeitslosigkeit miteinander zu vergleichen, denn beide Gründungsalternativen müssten sich im Hinblick auf ihre Motivation und ihren Erfolg deutlich voneinander unterscheiden. Nur sehr wenige Studien zum Gründungsgeschehen differenzieren nach dem der Selbstständigkeit vorangegangenen Erwerbs- bzw. Nichterwerbsstatus, obwohl bereits zu diesem Zeitpunkt Unterschiede im Entscheidungsverhalten zwischen arbeitslosen und beschäftigten Personen vorliegen. Während, rein monetär betrachtet, Beschäftigte nur zwischen ihrem jetzigen Einkommen und dem zukünftig erwarteten Einkommen aus der Selbstständigkeit entscheiden müssen, besteht für Arbeitslose die Wahl zwischen Einkommen aus einer möglichen abhängigen Beschäftigung, Einkommen aus einer eventuellen Selbstständigkeit oder weiterer Arbeitslosigkeit. Bezüglich des Erfolges sind Gründungen aus Beschäftigung vermutlich stärker darauf ausgelegt, zu wachsen und Arbeitsmöglichkeiten für andere Personen zu schaffen als Gründungen aus Arbeitslosigkeit, bei denen die Existenzsicherung des Gründers vorrangig sein dürfte. Ein weiteres, zweites Ziel der Arbeit besteht darin die bisherige empirische Evidenz zum Gründungsgeschehen zu erweitern, zu validieren bzw. zu verifizieren, indem Modelle der räumlichen Ökonometrie zur Analyse des regionalen Gründungsgeschehens genutzt werden. Ein solcher Schritt fehlt in bereits vorhandenen Studien ganz oder die Einbeziehung räumlicher Effekte erfolgt nur indirekt und unvollständig, was die erzielten Ergebnisse verzerren kann. Allein durch die Beobachtung und Kommunikation mit anderen Gründern im näheren Umfeld oder durch Netzwerke und Cluster dürften regionale Effekte entstehen, die das eigene Gründungsvorhaben beeinflussen. Um diese beiden Ziele zu verfolgen, gliedert sich die Arbeit in vier einzeln für sich lesbare Kapitel, für die in den nachfolgenden Abschnitten die jeweils detaillierten Forschungsschwerpunkte beschrieben sind. Die Analysen zur Gründungsaktivität aus Beschäftigung und aus Arbeitslosigkeit umfassen dabei vor allem die regionale Ebene (Kapitel 2 und Kapitel 3) berücksichtigen aber auch die individuelle Dimension (Kapitel 5). Während in den ersten beiden Kapiteln der Gründungszeitpunkt interessiert, widmen sich die beiden anschließenden Kapitel den direkten Beschäftigungswirkungen, d. h. der Entwicklung der Beschäftigung in der Gründung selbst bzw. dem Erfolg, der von Gründungen allgemein (Kapitel 4) und speziell von Gründungen aus Arbeitslosigkeit zu erwarten ist (Kapitel 5).

Purpose: The purpose of this study is to increase the understanding of what makes Swedish millennials follow and unfollow influencers on Instagram.   Metod: This study had a deductive and qualitative approach and has collected data through twelve semi-structured interviews.   Conclusion: This study concludes that millennials mainly follow influencers on Instagram to get inspiration for their own lives. One of the most common reasons why millennials are unfollowing influncers on Instagram is that influencers tend to publish too much content, which leads to information overload. Millennials also unfollow influencers due to the fact that their posts no longer appeal to them because they changed preferences or because influencers shift the focus of their content. This study also concluded that there is nothing that inhibits a millennial from unfollowing an influencer on Instagram other than the fact that it takes a little bit of effort to visit the account and press the unfollow button. / Syfte: Syftet är att öka förståelsen för vad som får svenska millennials att följa respektive avfölja influencers påInstagram. Metod: Den här studien har haft en deduktiv och kvalitativ karaktär och har samlat in data genom tolv semi-strukturerade intervjuer. Slutsats: Den här studien drar slutsatsen av att millennials främst följer influencers på Instagram för att få inspiration till sina egna liv. En av de vanligaste orsakernatill att millennials avföljer influncers på Instagram äratt influencerstenderar att publicera för mycket inlägg vilket leder till en informationsöverbelastning.Millennials avföljer också influencers för att deras inlägg inte längre tilltalar dem på grund av att de bytt preferenser eller att influencers bytt inriktning på sitt innehåll. Den här studien drar också slutsatsen att det finns egentligen inget som hämmar en millennial från att avfölja en influencer på Instagram annat än att de upplever det som tids-och energikrävande att gå in och avfölja.

High-dose verbenone, verbenone plus nonhost volatiles (NHVs), and both semiochemicals in combination with aggregant-baited funnel traps were tested for stand- level protection against mountain pine beetle attack for two consecutive years (2004-2005) at three seral high elevation whitebark pine sites in the Greater Yellowstone Ecosystem. In 2004, two 0.25-hectare treatments comprised of 25 high-dose verbenone pouches or verbenone pouches combined with single baited funnel traps were tested in a push-pull strategy. In 2005, 25 high-dose verbenone and 25 NHV pouches, or verbenone and NHV in combination with baited funnel trap clusters were tested. In both years, treatments were compared to 0.25-hectare control plots with no semiochemicals or funnel traps. The proportion of trees attacked by mountain pine beetle in treated plots was significantly reduced, when compared to control plots, at only one site treated with verbenone in 2004, and at only one site in 2005. High-dose verbenone alone, verbenone and NHVs, and both semiochemicals combined with baited funnel traps in a push-pull strategy did not consistently reduce the proportion of mountain pine beetle attacked trees relative to control plots. No covariates tested, including stand density, beetle population size, or tree size were consistently significant in explaining proportion of trees attacked.

Labor mobility in the rural area of Mainland China plays recently an important role in its economic development process. And this enormous and inexpensive labor attracts foreign investments, including Taiwanese investment, to enter Mainland China¡¦s market, and, further, drives economic development of Asia-Pacific Region. However, from the viewpoint of Rural-Urban Dualism theory, on the social level, rural labors can not take part in political life, and preserve their rights. Thus, they become ¡§Silent Class¡¨ in the Chinese urban society. On the economic level, serious public security problems derivative from labor disputes and conflicts, and it attracts highly concerns of Central of Chinese Communist Party (CCP), and issues ¡§Constructing Harmonious Community and Well-Off Society¡¨; and on the social level, continued expanding poverty gap, social rejection, and prejudice cause deep impact on those labors. This studying focus on the changing steps of supply and demand of rural labor, in order to discuss the developmental trend of transferring process of rural labor form past to present, even to the future. Therefore, this essay concentrates on the changing mobility of rural labor in some aspects, for example regions, identifications, careers, and life forms, and political, social economic, cultural, policy/urbanization, and market/occupation connections between rural and urban area. The Result of studying is, Central of CCP has 3 ways to solve problems beneath the surface of rural labor and urbanization: 1. Accelerating transferring process of rural surplus labor with economic development strategy; 2. Upgrading skill standard of rural labor, to guarantee employment; 3. Promoting and enlarging domestic consume, to constrain inflation. At the same time, the capability of labor unions should be reinforced and the organized degree of rural labor should be improved. Hoping that, they are able to play a more active role to protect rights of rural labors.